Peroxisome Proliferator-activated Receptor Gene Research Articles

Comprehensive analysis of peroxisome proliferator-activated receptors to predict the drug resistance, immune microenvironment, and prognosis in stomach adenocarcinomas.

Peroxisome proliferator-activated receptors (PPARs) exert multiple functions in the initiation and progression of stomach adenocarcinomas (STAD). This study analyzed the relationship between PPARs and the immune status, molecular mutations, and drug therapy in STAD. The expression profiles of three PPAR genes (PPARA, PPARD and PPARG) were downloaded from The Cancer Genome Atlas (TCGA) dataset to analyze their expression patterns across pan-cancer. The associations between PPARs and clinicopathologic features, prognosis, tumor microenvironment, genome mutation and drug sensitivity were also explored. Co-expression between two PPAR genes was calculated using Pearson analysis. Regulatory pathways of PPARs were scored using gene set variation analysis (GSVA) package. Quantitative real-time polymerase chain reaction (qRT-PCR), Western blot, Cell Counting Kit-8 (CCK-8) assay and transwell assay were conducted to analyze the expression and function of the PPAR genes in STAD cell lines (AGS and SGC7901 cells). PPARA, PPARD and PPARG were more abnormally expressed in STAD samples and cell lines when compared to most of 32 type cancers in TCGA. In STAD, the expression of PPARD was higher in Grade 3+4 and male patients, while that of PPARG was higher in patient with Grade 3+4 and age > 60. Patients in high-PPARA expression group tended to have longer survival time. Co-expression analysis revealed 6 genes significantly correlated with the three PPAR genes in STAD. Single-sample GSEA (ssGSEA) showed that the three PPAR genes were enriched in 23 pathways, including MITOTIC_SPINDLE, MYC_TARGETS_V1, E2F_TARGETS and were closely correlated with immune cells, including NK_cells_resting, T_cells_CD4_memory_resting, and macrophages_M0. Immune checkpoint genes (CD274, SIGLEC15) were abnormally expressed between high-PPAR expression and low-PPAR expression groups. TTN, MUC16, FAT2 and ANK3 genes had a high mutation frequency in both high-PPARA/PPARG and low-PPARA/PPARG expression group. Fourteen and two PPARA/PPARD drugs were identified to be able to effectively treat patients in high-PPARA/PPARG and low-PPARA/PPARG expression groups, respectively. We also found that the chemotherapy drug Vinorelbine was positively correlated with the three PPAR genes, showing the potential of Vinorelbine to serve as a treatment drug for STAD. Furthermore, cell experiments demonstrated that PPARG had higher expression in AGS and SGC7901 cells, and that inhibiting PPARG suppressed the viability, migration and invasion of AGS and SGC7901 cells. The current results confirmed that the three PPAR genes (PPARA, PPARD and PPARG) affected STAD development through mediating immune microenvironment and genome mutation.

Inhibition of Sodium-Glucose Cotransporter-2 during Serum Deprivation Increases Hepatic Gluconeogenesis via the AMPK/AKT/FOXO Signaling Pathway.

Sodium-dependent glucose cotransporter 2 (SGLT2) mediates glucose reabsorption in the renal proximal tubules, and SGLT2 inhibitors are used as therapeutic agents for treating type 2 diabetes mellitus. This study aimed to elucidate the effects and mechanisms of SGLT2 inhibition on hepatic glucose metabolism in both serum deprivation and serum supplementation states. Huh7 cells were treated with the SGLT2 inhibitors empagliflozin and dapagliflozin to examine the effect of SGLT2 on hepatic glucose uptake. To examine the modulation of glucose metabolism by SGLT2 inhibition under serum deprivation and serum supplementation conditions, HepG2 cells were transfected with SGLT2 small interfering RNA (siRNA), cultured in serum-free Dulbecco's modified Eagle's medium for 16 hours, and then cultured in media supplemented with or without 10% fetal bovine serum for 8 hours. SGLT2 inhibitors dose-dependently decreased hepatic glucose uptake. Serum deprivation increased the expression levels of the gluconeogenesis genes peroxisome proliferator-activated receptor gamma co-activator 1 alpha (PGC-1α), glucose 6-phosphatase (G6pase), and phosphoenolpyruvate carboxykinase (PEPCK), and their expression levels during serum deprivation were further increased in cells transfected with SGLT2 siRNA. SGLT2 inhibition by siRNA during serum deprivation induces nuclear localization of the transcription factor forkhead box class O 1 (FOXO1), decreases nuclear phosphorylated-AKT (p-AKT), and p-FOXO1 protein expression, and increases phosphorylated-adenosine monophosphate-activated protein kinase (p-AMPK) protein expression. However, treatment with the AMPK inhibitor, compound C, reversed the reduction in the protein expression levels of nuclear p- AKT and p-FOXO1 and decreased the protein expression levels of p-AMPK and PEPCK in cells transfected with SGLT2 siRNA during serum deprivation. These data show that SGLT2 mediates glucose uptake in hepatocytes and that SGLT2 inhibition during serum deprivation increases gluconeogenesis via the AMPK/AKT/FOXO1 signaling pathway.

MicroRNAs targeting peroxisome proliferator-activated receptor (PPAR) gene are differentially expressed in low birth weight placentae

IntroductionPeroxisome proliferator-activated receptors (PPARs) are activated by natural ligands like fatty acids and influence placental angiogenesis and pregnancy outcome. However, the underlying molecular mechanisms are not clear. This study aims to investigate the association of maternal and placental fatty acid levels with DNA methylation and microRNA regulation of PPARs in the placentae of women delivering low birth weight (LBW) babies. MethodsThis study includes 100 women delivering normal birth weight (NBW) baby and 70 women delivering LBW baby. Maternal and placental fatty acids levels were estimated by gas chromatograph. Gene promoter methylation and mRNA expression of PPARs was analyzed using Epitect Methyl-II PCR assay kit and RT-PCR respectively. Expression of miRNAs targeting PPAR mRNA were analyzed using a Qiagen miRCURY LNA PCR Array on RT-PCR. ResultsPlacental docosahexaenoic acid (DHA) levels and placental mRNA expression of PPARα and PPARγ were lower (p < 0.05 for all) in the LBW group. Differential expression of miRNAs (upregulated miR-33a-5p and miR-22-5p; downregulated miR-301a-5p, miR-518d-5p, miR-27b-5p, miR-106a-5p, miR-21-5p, miR-548d-5p, miR-17-5p and miR-20a-5p) (p < 0.05 for all) was observed in the LBW group. Maternal and placental polyunsaturated fatty acids and total omega-3 fatty acids were positively associated while saturated fatty acids were negatively associated with expression of miRNAs (p < 0.05 for all). Placental expression of miRNAs were positively associated with birth weight (p < 0.05 for all). DiscussionOur data suggests that maternal fatty acid status is associated with changes in the placental expression of miRNAs targeting PPAR gene in women delivering LBW babies.

Prognostic biomarkers in and selection of surgical patients with hepatocellular carcinoma.

The Faculty of Health and Medical Sciences at the University of Copenhagen has accepted this dissertation for public defence for the doctoral degree in medicine, Copenhagen, January 10, 2023 Bente Merete Stallknecht, Head of Faculty Assessment committee Chair Professor Susanne Dam Poulsen, University of Copenhagen Opponents Professor Pål-Dag Line, University of Oslo Professor Christian Toso, University of Geneva Chair of the defence ceremony Professor Kirsten Grønbæk, University of Copenhagen The defense took place on February 14, 2023 at 14:00 CET at Rigshospitalet, Auditorium 2, Blegdamsvej 9, 2100 Copenhagen Ø This thesis summarizes a significant part of the research that I carried out from 2015 to 2020 alongside my surgical specialization. Since defending my PhD in 2013, my research area of interest has shifted towards liver surgery and transplantation, in particular prognostic aspects related to malignancy. The complexity of liver surgery, including anatomy, technique and medical aspects has always sparked my interest. The work in this thesis has paved the way for the current and future area of interest of my research group at Department of Surgery and Transplantation, Rigshospitalet. I would like to express my deepest appreciation to Allan Rasmussen for inspiration and guidance. Allan introduced me to this specific field of research and to many important research partners in Rigshospitalet, Denmark and Scandinavia. I would like to thank Jens Hillingsø and all of my wonderful colleagues at Department of Surgery and Transplantation, Rigshospitalet for their support and for offering me the opportunity to carry out my research. I would also like to thank the collaborators on the studies for their excellent work and important scientific inputs. These include: Andreas Rostved, Carina Lund Sørensen, Peter Nørgaard Larsen and Nicolai Schultz, Department of Surgery and Transplantation, Rigshospitalet; Jakob Burcharth and Jacob Rosenberg, Department of Surgery, Herlev Hospital; Jane Preuss Hasselby and Gro Linno Willemoe, Department of Pathology, Rigshospitalet; Jan-Michael Kugler, Institute for Molecular and Cellular Medicine, Panum Institute; Christina Westmose Yde, Lise Ahlborn and Finn Cillius Nielsen, Center for Genomic Medicine, Rigshospitalet; Claus Lindbjerg Andersen and Tenna Henriksen, Department for Molecular Medicine (MOMA), Aarhus University Hospital/Skejby; Kristoffer Rohrberg, Phase 1 Unit, Department of Oncology, Rigshospitalet; Lau Caspar Thygesen, National Institute of Public Health, University of Southern Denmark; and the European Liver and Intestine Transplant Association (ELITA) study group. Thanks to my research group for daily inspiration, good discussions and laughs (Delal Akdag, Jeanett Klubien, Lucas Knøfler og Sophie Nordkild). This work was financially supported by the Harboe foundation, the Risom foundation and the Dagmar Marchall foundation, for which I am grateful. Finally, I would like to thank my wife Line for her tremendous support over the many years where my research mostly has been conducted in my spare time. Thanks to my three children for filling me with love each day and thanks to my mother and my brother for continuous support. A special thanks to my father who passed away in the fall. He was always proud, supportive and encouraging. Hans-Christian PommergaardMD, DMSc, PhDDepartment of Surgery and TransplantationRigshospitalet, University of Copenhagen Charlottenlund, January 2023 Pommergaard HC, Burcharth J, Rosenberg J, Rasmussen A. Serologic and molecular biomarkers for recurrence of hepatocellular carcinoma after liver transplantation: a systematic review and meta-analysis. Transplant Rev (Orlando). 2016 Jul;30(3):171–7. Pommergaard HC, Hasselby JP, Willemoe GL, Ralbovska A, Rostved AA, Rasmussen A, Schultz NA, Hillingsø J, Larsen PN, Kugler JM. Peroxisome proliferator-activated receptor activity correlates with poor survival in patients resected for hepatocellular carcinoma. J Hepatobiliary Pancreat Sci. 2021 Apr;28(4):327–35. Pommergaard HC, Rasmussen A, Hillingsø J, Kugler JM. Aldehyde dehydrogenase expression may be a prognostic biomarker and associated with liver cirrhosis in patients resected for hepatocellular carcinoma. Surg Oncol. 2021 Nov 23;40:101677. Pommergaard HC, Yde CW, Ahlborn LB, Andersen CL, Henriksen TV, Hasselby JP, Rostved AA, Sørensen CL, Rohrberg KS, Nielsen FC, Rasmussen A. Personalized circulating tumour DNA in patients with hepatocellular carcinoma: a pilot study. Mol Biol Rep. 2021 Nov 22. Pommergaard HC, Rostved AA, Adam R, Thygesen LC, Salizzoni M, Gómez Bravo MA, Cherqui D, Filipponi F, Boudjema K, Mazzaferro V, Soubrane O, García-Valdecasas JC, Prous JF, Pinna AD, O'Grady J, Karam V, Duvoux C, Rasmussen A. Vascular invasion and survival after liver transplantation for hepatocellular carcinoma: a study from the European Liver Transplant Registry. HPB (Oxford). 2018 Aug;20(8):768–75. Pommergaard HC, Rostved AA, Adam R, Thygesen LC, Salizzoni M, Gómez Bravo MA, Cherqui D, De Simone P, Boudjema K, Mazzaferro V, Soubrane O, García-Valdecasas JC, Fabregat Prous J, Pinna AD, O'Grady J, Karam V, Duvoux C, Rasmussen A. Locoregional treatments before liver transplantation for hepatocellular carcinoma: a study from the European Liver Transplant Registry. Transpl Int. 2018 May;31(5):531–9. Pommergaard HC, Rostved AA, Adam R, Rasmussen A, Salizzoni M, Gómez Bravo MA, Cherqui D, De Simone P, Houssel-Debry P, Mazzaferro V, Soubrane O, García-Valdecasas JC, Prous JF, Pinna AD, O'Grady J, Karam V, Duvoux C, Thygesen LC. Mortality after transplantation for hepatocellular carcinoma: a study from the European Liver Transplant Registry. Liver Cancer. 2020 Aug;9(4):455–67. Hepatocellular carcinoma (HCC) is the sixth most common cancer and the fourth leading cause of cancer deaths globally with increasing incidence. In most cases, HCC develops as a result of an underlying chronic liver disease. The stage at the time of diagnosis is closely correlated with prognosis with a 5-year survival of more than 70% for patients with early-stage HCC. These patients are generally suitable for curative treatment, such as resection, ablation or liver transplantation. In contrast, 5-year survival may be as low as 5% for patients in advanced stages of the disease. Due to organ shortage and the risk of mortality for patients on the waiting list for liver transplantation, survival in patients undergoing transplantation due to HCC should be comparable to those with benign indications. However, there is an ongoing debate concerning the best criteria for the selection of patients with HCC for transplantation, as the current criteria may rule out patients with a good prognosis. Liver resection may be performed in patients with HCC in non-cirrhotic livers and cirrhotic livers with preserved liver function. However, careful selection of patients is crucial due to high recurrence risk (>50%) and severe complications in >10% of liver resections for HCC. The aims of this thesis were to identify prognostic biomarkers in and improve the selection of patients undergoing transplantation and resection for HCC, respectively. Yet another aim was to improve upon the existing early detection of recurrence. The seven studies included in this thesis provided novel insights into prognostic biomarkers and selection of surgical patients with HCC. Firstly, the literature was reviewed regarding biomarkers to detect recurrence after transplantation for HCC. Next, two novel tumour-related prognostic biomarkers were identified and the applicability of circulating tumour DNA (ctDNA) was evaluated. Moreover, using data from the European Liver Transplant Registry (ELTR), vascular invasion and locoregional treatment were identified as important prognostic markers. Lastly, using propensity score calibration, prognostic differences between HCC in cirrhotic and non-cirrhotic livers were clarified. The studies included in this thesis add important knowledge towards better selection of patients for transplantation and resection of HCC, respectively. In future guidelines, alpha-fetoprotein, radiological markers of vascular invasion and response to locoregional treatment may be included in selection criteria for transplantation of patients with HCC. In addition, the novel biomarkers identified may add important prognostic information and improve the selection of patients. For resected patients, a proper balance between survival benefit and risk of recurrence and complications may be ensured. For transplanted patients, optimized selection means that the utility of donor organs is maximized by more accurately selecting patients with favourable tumour biologies. Hepatocellulært karcinom (HCC) er den sjette mest almindelige kræftsygdom og den fjerde hyppigste årsag til kræftdødsfald globalt med stigende forekomst. I de fleste tilfælde udvikler HCC sig som følge af en underliggende kronisk leversygdom. Stadie på diagnosetidspunktet er tæt korreleret med prognose med femårs overlevelse på mere end 70% hos patienter med HCC i tidligt stadium. Disse patienter kan generelt modtage kurativt intenderet behandling, såsom resektion, ablation eller levertransplantation. I modsætning hertil kan femårs overlevelse være helt ned til 5% hos patienter med fremskredne stadier. På grund af organmangel og død på venteliste til levertransplantation bør overlevelse hos patienter der transplanteres for HCC være sammenlignelig med overlevelse for benigne indikationer. Der er aktuelt debat om de bedste kriterier til at selektere patienter med HCC til transplantation, da nuværende kriterier udelukker visse patienter med en god prognose. Leverresektion kan udføres hos patienter med HCC i en ikke-cirrotisk lever eller i en cirrotisk lever med bevaret leverfunktion. Imidlertid er omhyggelig udvælgelse af patienter afgørende på grund af en høj risiko for recidiv (>50%) og alvorlige komplikationer i >10% af leverresektioner for HCC. Formålet med denne disputats var at identificere prognostiske biomarkører og forbedre selektion af patienter til henholdsvis transplantation og resektion for HCC. Desuden var målet at forbedre tidlig identifikation af recidiv. De syv studier inkluderet i denne disputats giver ny indsigt i prognostiske biomarkører og selektion af kirurgiske patienter med HCC. Eksisterende biomarkører for recidiv efter transplantation for HCC blev systematisk undersøgt. Dernæst blev to nye tumorrelaterede prognostiske biomarkører identificeret, og anvendeligheden af cirkulerende tumor-DNA (ctDNA) blev evalueret. Ved hjælp af data fra European Liver Transplant Registry (ELTR) blev mikrovaskulær invasion og lokalbehandling af HCC identificeret som vigtige prognostiske markører. Endelig blev prognostiske forskelle mellem HCC i cirrotisk og ikke-cirrotisk lever afklaret ved hjælp af propensity score kalibrering. Studierne inkluderet i denne disputats tilfører vigtig viden til bedre selektion af patienter til henholdsvis transplantation og resektion af HCC. I fremtidige retningslinjer kan alfa-føto protein, radiologiske markører for microvaskulær invasion og respons på lokalbehandling muligvis inkluderes i selektionskriterier for transplantation af HCC. Derudover kan de nye identificerede biomarkører tilføje vigtig prognostisk information og forbedre udvælgelsen af patienter. For resecerede patienter kan der skabes en balance mellem overlevelsesgevinst og risiko for recidiv og komplikationer. For transplanterede patienter betyder optimeret selektion, at udnyttelse af donororganer maksimeres ved mere præcis udvælgelse patienter med en gunstig tumorbiologi. Hepatocellular carcinoma (HCC) is the sixth most common cancer and the fourth leading cause of cancer deaths globally with increasing incidence. HCC represents 75–85% of primary liver cancers and has a strong male predominance, both regarding incidence and mortality [1, 2]. In 70–90% of cases, HCC arises in patients with cirrhotic livers [3, 4]. Approximately one-third of patients with cirrhosis will develop HCC in their lifetime (1–8% annual incidence) [5, 6]. On a global level, hepatitis B virus (HBV) is the primary cause of HCC (33%), followed by alcohol (30%), hepatitis C virus (HCV) (21%) and other aetiologies (16%) [2]. Most deaths due to HCC occur in Asia, and the primary cause is endemic HBV infections. However, the incidence of HCC is rising in Western countries as a result of the increasing prevalence of non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH) and alcohol-related liver disease [7]. HCC seems to be less frequent in patients with alcoholic and NASH cirrhosis than in patients with viral hepatitis [6, 8]. However, the annual incidence of HCC in patients with NASH is 1–2%, and it is estimated that 6 million people in the United States alone have NASH [9] and that obesity and/or diabetes accounts for approximately 37% of the HCC cases [10]. Current guidelines suggest that patients with cirrhosis (Child-Pugh A/B and Child-Pugh C (awaiting transplantation)) and non-cirrhotic HBV patients with intermediate or high risk of HCC should undergo surveillance for HCC with abdominal ultrasound every 6 months [11]. This modality has a limited sensitivity (45%) for the detection of HCC [12], which may be reduced further by obesity and cirrhosis [13]. However, evidence suggests that surveillance improves the identification of HCC at an early stage and hence the chances of curative treatment and survival [14]. Patients with early-stage HCC are generally suitable for curative treatments, such as resection, ablation or liver transplantation. In contrast, patients with advanced-stage disease are typically only offered palliative oncologic treatment or the best supportive care. Patients with intermediate-stage disease may be offered chemo-embolization [15]. Consequently, the stage at the time of diagnosis is closely correlated with the prognosis with a 5-year survival of more than 70% for patients with early-stage HCC compared with only 5% for patients in advanced stages of the disease [11, 16]. In most centres, a multidisciplinary approach is adopted with treatment allocation based on the stage of the disease, using, for example, the Barcelona Clinic Liver Cancer (BCLC) classification [17]. A contemporary approach includes treatment stage migration, wherein a patient with a specific disease stage not suited for the first-line treatment may be allocated a treatment recommended for a different disease stage [18-20]. The concepts are integrated with the 2022 BCLC guideline update [15] (Fig. 1). With evidence suggesting that prognosis is related to first-line treatment irrespective of tumour stage, an alternative approach has been suggested [21]. In the concept of therapeutic hierarchy (Fig. 2), treatments are decided independent of stage and hierarchical use of available therapies according to their specific survival benefit [22]. Previously, sorafenib was the only available systemic treatment. It is associated with significant adverse events and only minor survival benefits [23]. Based on the evidence from phase III trials, several additional systemic therapies have been approved including atezolizumab plus bevacizumab, lenvatinib, regorafenib, cabozantinib and ramucirumab [24]. Moreover, trials are now evaluating combination therapies. According to the 2022 guideline update from BCLC, Atezolizumab-Bevacizumab/Durvalumab-Tremelimumab is now recommended as first-line systemic treatment [15] (Fig. 1). Hepatocellular carcinoma may be diagnosed solely based on imaging using the Liver Imaging Reporting and Data System (LI-RADS) [25], thereby eliminating the need for preoperative histological diagnosis by tumour biopsy. LI-RADS is valid in patients with high-risk of developing HCC, namely patients with cirrhosis, chronic HBV and current or prior HCC. However, LI-RADS may not be applied in patients without these risk factors, in patients under 18 years of age and in those with cirrhosis due to a vascular disorder or congenital hepatic fibrosis [25]. Moreover, a recent study showed that LI-RADS may be valid in a larger proportion of patients with an increased risk of HCC than previously considered [26]. However, biopsy in patients without increased risk, including patients with non-cirrhotic livers, is still needed to confirm diagnosis. Due to organ shortage and the risk of mortality for patients on waiting list for liver transplantation, survival in patients undergoing transplantation due to HCC should be comparable to those with benign indications [27]. However, there is an ongoing debate concerning the best criteria for selection of patients with HCC for transplantation. Some argue that the current criteria may rule out patients with a good prognosis [28]. Thus, better selection criteria are needed. Patients with HCC in a non-cirrhotic liver without macrovascular invasion or extra-hepatic spread may undergo curative liver resection. Liver resection may also be performed in patients with HCC in a cirrhotic liver with preserved liver function, no portal hypertension and sufficient volume of the future liver remnant (FLR) [11]. Careful selection of patients is essential due to a high recurrence risk (>50%) [29] and severe complications in >10% of liver resections for HCC. Age, model for end-stage liver disease (MELD) score, liver stiffness and serum albumin were independent predictors of complications [30], while portal hypertension, extend of resection, MELD score, bilirubin and indocyanine green (ICG) clearance were associated with the risk of postoperative liver failure [31-33]. However, knowledge of cancer-related prognostic biomarkers is lacking. To optimize the selection of patients who will benefit from a high-risk surgical procedure, prognostic biomarkers are needed. Furthermore, as liver disease may not be easily diagnosed in some patients, additional biomarkers to identify high-risk patients, for example, with fibrosis/cirrhosis may be useful [34]. However, so far, no prognostic biomarkers have been widely accepted in clinical practice. Early identification of recurrence after surgical treatment may be associated with better prognosis [29]. Imaging studies currently used for follow-up may be insufficient for smaller lesions (<2 cm) [35, 36]. Thus, tools for early detection of recurrence are needed. Hypothesis 1 was investigated by conducting a systematic review and a meta-analysis using the PubMed and Scopus databases on studies investigating biomarkers for recurrence of HCC after liver transplantation. Hypotheses 2 and 3 were investigated using tissue stored in the Danish Cancer Biobank from patients undergoing liver resection for HCC at Rigshospitalet, Denmark between 2014 and 2018. Hypothesis 4 was investigated by evaluating the detection of ctDNA in blood preoperatively in a prospective pilot study in patients undergoing liver resection for HCC at Rigshospitalet, Denmark in 2018 and 2019. Hypotheses 5, 6 and 7 were investigated using data from the European Liver Transplant Registry (ELTR) for the period from 1990 to 2016, where pre-, peri- and postoperative data from 174 liver transplantation centres in 28 European countries have been collected, including data on tumour characteristics and locoregional treatment in patients with HCC. Regarding liver transplantation, donor livers are scarce with substantial mortality of patients in waiting lists [37]. Thus, the prognosis for recipients transplanted for HCC should be comparable to that of benign indications to justify transplantation [27]. Current selection criteria, based on the size and number of HCC, are insufficient, as they may rule out patients with good prognosis despite being outside the established criteria [28]. Inclusion of biomarkers in the selection criteria may improve the selection of patients for liver transplantation for HCC. However, except for alpha-fetoprotein (AFP), no biomarkers are included in the existing selection criteria for transplantation due to HCC. Surgical resection for HCC may be a high-risk procedure, especially in patients with cirrhosis, with a substantial risk of recurrence [11] and complications, including liver failure [30]. Prognostic biomarkers may improve the selection of patients who will benefit from a surgery and also provide more precise preoperative information to them. Currently, tumour burden, liver function and performance score are used to select patients for surgical resection [15]. Thus, biomarkers may be used in conjunction with these criteria to determine the optimal treatment strategy. Currently, no biomarkers have been widely incorporated into clinical practice. A prognostic biomarker may be defined as a factor indicating the likelihood of a future recurrence, progression or death in a population [38]. For the purpose of this thesis, a prognostic biomarker was defined as a blood or tumour marker associated with prognosis not currently included in standard diagnostic workups. A vast amount of research has been conducted in an effort to identify clinically useful biomarkers in patients with HCC. However, relatively less effort has gone into the validation of positive results. In an attempt to gain an overview of the level of evidence, directions for the design of studies and the possibilities for clinical implementation, a systematic review and a meta-analysis were conducted in Study I. PubMed and Scopus databases were searched up to the year 2016 to identify observational studies investigating blood-borne or tumour markers for recurrence of HCC after liver transplantation. Meta-analyses were performed in biomarkers investigated in multiple studies with sufficient homogeneity. Meta-analysis was omitted when heterogeneity was above 75% as assessed by the I2 test. The generic inverse variance method was utilized to incorporate adjusted hazard ratio (HR) estimates from individual studies. This was applied to adjust for confounding in individual studies. Alpha-fetoprotein was investigated in 49 studies of which 17 studies were included in the meta-analysis. These studies were defined by using a pre-transplant AFP >400 NT/mL as cut-off [39-55]. The pooled estimate (HR) regarding risk of recurrence was 2.69 [2.08–3.47], with an acceptable heterogeneity of 46% (Fig. 3). However, the funnel plot indicated a risk of publication bias with a lack of smaller negative studies. Des-gamma-carboxy prothrombin (DCP/PIVKA) was investigated in seven studies. Four studies [45, 48, 57, 58] with comparable outcome definition and cut-off levels (PIVKA level >100–400 mAU/mL) were included in a meta-analysis with an HR of 5.99 [3.27–10.98] regarding the risk of recurrence. Heterogeneity of the four studies was 0% (Fig. 4). Neutrophil to lymphocyte ratio (NLR) was found to be associated with recurrence in four studies [59-62]. However, a meta-analysis was not conducted due to the high heterogeneity (>75%) between the studies. Moreover, circulating DNA – particularly single nucleotide polymorphisms rs894151 and rs12438080 – was found to be associated with recurrence in one of the studies [63]. Following protein markers in HCC tumours has been shown to be associated with recurrence: anti-Ki67 [64], calpain small subunit 1 (Capn4) [65], CD34 antigen [66], CD147 [67], NDRG1 [68], cadherins [64], x-linked inhibitor of apoptosis protein-associated factor 1 (XAF1) [69], hepatocyte nuclear factor 1 (HNF1) [70] and hippo cell signal pathway [71]. Enzymes were investigated in four studies. Two of them investigated matrix metalloproteinases (MMPs) measured in tumour [67, 72]. In a meta-analysis, there was no association with recurrence with an HR of 2.12 [0.21–21.43], with a high heterogeneity of 74% (Fig. 5). However, MMP measured in adjacent stromal tissue may be associated with recurrence [67]. In two additional studies, histone deacetylases (HDACs) [73] and O-GlcNAcylation [52] were associated with recurrence. Micro-RNA in tumour was associated with recurrence in four studies [41, 44, 54, 74]. Moreover, long noncoding RNAs, in particular, HOTAIR in tumour [50] and MALAT-1 [75], were associated with recurrence. DNA/genes associated with recurrence included CIMP [76], MACC1 [42, 51], and cell-cycle genes pRb and p16 [77]. Lastly, allelic imbalance in microsatellites was associated with recurrence in a meta-analysis with two studies and an HR of 13.49 [3.17–57.30] and 0% heterogeneity [78, 79] (Fig. 6). The majority of biomarkers were only investigated in a single study, and results have not been validated. The included studies considered different types of aetiology for HCC, and patients may therefore not be comparable. Moreover, outcome definition differed between the studies. For meta-analyses, there was an insufficient number of studies for meaningful evaluation of publication bias by means of funnel plots, except for AFP where a lack of smaller negative studies suggested a risk of publication bias. Since the publication of Study I in 2016, additional studies have been published on biomarkers for recurrence after liver transplantation for HCC. Thus, an updated literature search was performed. Regarding blood-borne biomarkers, platelet-to-lymphocyte ratio (PLR), controlling nutritional status (CONUT) and the prognostic nutritional index (PNI) were associated with recurrence [80]. Serum homocysteine was associated with recurrence in recipients with AFP-negative disease [81]. Moreover, markers of angiogenesis and inflammation (plasma VEGFR1, VEGF and VEGF-C) and circulating exosomal miR-92b were associated with recurrence [82, 83]. Regarding tumour tissue biomarkers, increased LGALS3 and LGALS3BP gene and protein expression were associated with recurrence [84]. In addition, TP53 mutations, high fractional allelic loss, hypomethylation of 8 tumour suppressors and absence of CTNNB1 mutations were of prognostic significance [85]. Lastly, tumour evolutionary distance by genome-wide single-nucleotide polymorphism genotyping was associated with recurrence and validated in a replication cohort [86]. As in liver transplant recipients, AFP is the most commonly evaluated biomarker after liver resection for HCC. However, only 10–20% of early-stage HCC patients present with abnormal AFP, which may be correlated with an aggressive HCC type (e.g., S2 class, epithelial cell adhesion molecule (EpCAM) positive) [87-89]. Moreover, AFP has low accuracy, as elevated AFP in patients with cirrhosis may reflect viral hepatitis and background liver disease in addition to HCC development [90]. Despite these limitations, AFP level was associated with recurrence with results externally validated in international cohorts [91, 92]. Furthermore, AFP level at recurrence predicted survival [93]. The following additional blood-borne biomarkers were associated with recurrence after resection for HCC: DCP [94], albumin-bilirubin score [91], circulating EpCAM positive tumour cells [95], preoperative CRP [96], preoperative neutrophil-to-lymphocyte ratio [97] and ratio of postoperative to preoperative circulating levels of cancer stem cell (CSC) markers K19 and CD44 [98]. Peroxisome proliferator-activated receptors (PPARs) are ligand-dependent nuclear receptors that regulate lipid metabolism and transduce metabolic and nutritional signals into transcriptional responses [99-101]. The association between PPAR and the development of HCC is not fully understood, and studies are somewhat conflicting. Moreover, the relationship may depend on context and species [102]. In some studies, high PPAR activity seems beneficial. Thus, it may reduce tumour growth via anti-inflammatory mechanisms [103], improve liver function [104] and resolve NASH [105]. As opposed to this, studies suggested unwanted consequences of PPAR activation, such as the induction of HCC due to regulation of the cell cycle [106] or formation of steatosis [107]. However, the prognostic importance in patients with HCC has not been investigated in a clinical setting. In Study II, we presented the results of RNA sequencing of HCC and non-tumour liver tissue in 52 patients undergoing liver resection. Based on the expression of PPAR target genes in heat maps (Fig. 7), we identified a group of patients (cancer cluster 3) with decreased overall survival (3-year overall survival of 48.6% vs 81.7% amongst controls, Fig. 8). The correlation remained significant in multivariate analysis adjusted for age, cirrhosis, microvascular invasion, number of tumours and resection margins (Table 1). Furthermore, we found that PPAR expression in non-tumour liver tissue was correlated with cirrhosis. In an earlier study using publicly available data from The Cancer Genome Atlas (TCGA), it was found that patients with HCC and low PPAR activity in tumour had significantly reduced overall survival [109]. However, in that study, PPAR activity from tumour tissue in patients with HCC was compared with liver tissue from healthy patients. Moreover, in a large study, PPAR expression evaluated with immunohistochemistry was correlated with shorter survival [110]. While immunohistochemistry may be a good surrogate for PPAR activity, transcriptome analysis allows a more direct evaluation of activity, as PPAR requires ligands and co-receptors to regulate gene expression [111]. In a phase 2 trial, patients with NASH were randomized to receive Lanifibranor, a PPAR agonist or a placebo [112]. Patients in the treatment arm receiving 1200 mg daily had reduced disease activity measured by the steatosis, activity and fibrosis [SAF] scoring system without the worsening of fibrosis. This suggested a possible clinical implication of PPAR not confined to HCC. Together with the correlation between PPAR and cirrhosis found in Study II, these findings may reflect that PPAR activity is important for liver cell homoeostasis. To our knowledge, Study II was the first clinical study to establish the prognostic value of PPAR gene activit

The Influence of FAM13A and PPAR-γ2 Gene Polymorphisms on the Metabolic State of Postmenopausal Women

Recently, we have observed two significant pandemics caused by communicable (COVID-19) and non-communicable factors (obesity). Obesity is related to a specific genetic background and characterized by immunogenetic features, such as low-grade systemic inflammation. The specific genetic variants include the presence of polymorphism of the Peroxisome Proliferator-Activated Receptors gene (PPAR-γ2; Pro12Ala, rs1801282, and C1431T, rs3856806 polymorphisms), β-adrenergic receptor gene (3β-AR; Trp64Arg, rs4994), and Family With Sequence Similarity 13 Member A gene (FAM13A; rs1903003, rs7671167, rs2869967). This study aimed to analyze the genetic background, body fat distribution, and hypertension risk in obese metabolically healthy postmenopausal women (n = 229, including 105 lean and 124 obese subjects). Each patient underwent anthropometric and genetic evaluations. The study has shown that the highest value of BMI was associated with visceral fat distribution. The analysis of particular genotypes has revealed no differences between lean and obese women except for FAM13A rs1903003 (CC), which was more prevalent in lean patients. The co-existence of the PPAR-γ2 C1431C variant with other FAM13A gene polymorphisms [rs1903003(TT) or rs7671167(TT), or rs2869967(CC)] was related to higher BMI values and visceral fat distribution (WHR > 0.85). The co-association of FAM13A rs1903003 (CC) and 3β-AR Trp64Arg was associated with higher values of systolic (SBP) and diastolic blood pressure (DBP). We conclude that the co-existence of FAM13A variants with C1413C polymorphism of the PPAR-γ2 gene is responsible for body fat amount and distribution.

Oxysterol-binding protein-like 3 is a novel target gene of peroxisome proliferator-activated receptor γ in fatty liver disease

Oxysterol-binding protein-like 3 (OSBPL3) plays a key role in the development of fatty liver disease. Herein, we found that OSBPL3 is highly expressed in the fatty liver of humans and mice. Although high expression of Osbpl3 was observed in the fatty liver of type 2 diabetic ob/ob mice, liver-specific Pparg knockout ameliorated this increase in these mice. Moreover, high hepatic Osbpl3 expression was observed in other mice models of fatty liver disease, such as leptin receptor-mutant db/db and alcohol-fed mice. Analysis of the human liver transcriptome data revealed that hepatic OSBPL3 expression is higher in patients with advanced non-alcoholic fatty liver disease (NAFLD) when compared to those with mild NAFLD. Reporter and electrophoretic mobility shift assays showed that PPARγ positively regulates Osbpl3 transcription by binding to the two functional PPARγ-responsive elements present in the 5′ upstream region. Overall, our results indicate that Osbpl3 is a novel PPARγ target in the fatty liver.

Fibroblast growth factor 21 as a potential master regulator in metabolic disorders.

FGF21 is an endocrine hormone that controls key metabolic processes and induces the synthesis of glucose transporters, resulting in increased glucose absorption levels in fat cells. It is expressed in multiple metabolically active organs and tissues. FGF21 is also a powerful regulator of glucose homeostasis as a direct downregulating gene of peroxisome proliferator-activated receptor (PPAR), which plays a role in regulating the activity of glucose and lipids. Attempts were made to understand various aspects related to FGF21, including properties like receptor binding and genomic linkage map, along with the information about the genes that function in the upregulation of FGF21 and how it, directly and indirectly, downregulates the genes that are vital in various metabolic pathways. Furthermore, various gene regulatory analyses on the specific gene concerning unique micro RNAs and long non-coding RNAs that target FGF21 and alter its functioning along with single-nucleotide polymorphisms (SNPs) were observed, that are the common cause of cell dysregulation, leading to different metabolic diseases and pathogenesis of cancer. Unique protein-protein interaction and cross talk between FGF21 and PPARγ shed light on their combined role in metabolic disorder-related regulatory activities. Its potential and unique role as an effective biomarker for various cardiovascular and metabolic disorders have also been highlighted. This study attempts to highlight the pleiotropic role of FGF21 activity following its overexpression and inhibition of cascades that results in the induction of obesity from diet and simultaneously signals adipocytes to absorb glucose and decrease triglyceride and blood sugar levels in diabetic models (after administration), rendering it a promising treatment for several metabolic and cardiovascular disorders.

The Influence of the Differentiation of Genes Encoding Peroxisome Proliferator-Activated Receptors and Their Coactivators on Nutrient and Energy Metabolism.

Genetic components may play an important role in the regulation of nutrient and energy metabolism. In the presence of specific genetic variants, metabolic dysregulation may occur, especially in relation to the processes of digestion, assimilation, and the physiological utilization of nutrients supplied to the body, as well as the regulation of various metabolic pathways and the balance of metabolic changes, which may consequently affect the effectiveness of applied reduction diets and weight loss after training. There are many well-documented studies showing that the presence of certain polymorphic variants in some genes can be associated with specific changes in nutrient and energy metabolism, and consequently, with more or less desirable effects of applied caloric reduction and/or exercise intervention. This systematic review focused on the role of genes encoding peroxisome proliferator-activated receptors (PPARs) and their coactivators in nutrient and energy metabolism. The literature review prepared showed that there is a link between the presence of specific alleles described at different polymorphic points in PPAR genes and various human body characteristics that are crucial for the efficacy of nutritional and/or exercise interventions. Genetic analysis can be a valuable element that complements the work of a dietitian or trainer, allowing for the planning of a personalized diet or training that makes the best use of the innate metabolic characteristics of the person who is the subject of their interventions.

Fingolimod treatment modulates PPARγ and CD36 gene expression in women with multiple sclerosis.

Fingolimod is an oral immunomodulatory drug used in the treatment of multiple sclerosis (MS) that may change lipid metabolism. Peroxisome proliferator-activated receptors (PPAR) are transcription factors that regulate lipoprotein metabolism and immune functions and have been implicated in the pathophysiology of MS. CD36 is a scavenger receptor whose transcription is PPAR regulated. The objective of this study was to evaluate whether fingolimod treatment modifies PPAR and CD36 gene expression as part of its action mechanisms. Serum lipoprotein profiles and PPAR and CD36 gene expression levels in peripheral leukocytes were analysed in 17 female MS patients before and at 6 and 12 months after fingolimod treatment initiation. Clinical data during the follow-up period of treatment were obtained. We found that fingolimod treatment increased HDL-Cholesterol and Apolipoprotein E levels and leukocyte PPARγ and CD36 gene expression. No correlations were found between lipid levels and variations in PPARγ and CD36 gene expression. PPARγ and CD36 variations were significantly correlated during therapy and in patients free of relapse and stable disease. Our results suggest that PPARγ and CD36-mediated processes may contribute to the mechanisms of action of fingolimod in MS. Further studies are required to explore the relation of the PPARγ/CD36 pathway to the clinical efficacy of the drug and its involvement in the pathogenesis of the disease.

Genome-wide identification and expression of the peroxisome proliferator-activated receptor gene family in the Tibetan highland fish Gymnocypris przewalskii.

Peroxisome proliferator-activated receptor (PPAR) plays an important role in the regulation of lipid metabolism and has been widely identified in diverse species. Gymnocypris przewalskii is a native fish of the Qinghai Tibetan Plateau that survives in a chronically cold environment. In the current study, we conducted genome-wide identification of PPAR genes, revealing the existence of seven PPARs in the G. przewalskii genome. Collinearity was observed between two copies of PPARαb and PPARγ in G. przewalskii, suggesting that the additional copy might be gained through whole genome duplication. Both phylogenetic and multiple sequence alignment analyses indicated that PPARs in G. przewalskii were conserved with teleosts. The cold treatment (10°C and 4°C) led to the developmental delay of G. przewalskii embryos. Continuous expression of PPARs was observed during the embryonic development of G. przewalskii under normal and cold conditions, with significantly different transcriptional patterns. These results indicated that PPARs participated in the embryonic development of G. przewalskii, and were involved in the cold response during development. The current study proposed a potential role of PPARs in the cold response in the embryonic development of G. przewalskii, which shed light on understanding cold adaptation in Tibetan highland fish.

Retracted: Peroxisome Proliferator-Activated Receptor Gene Knockout Promotes Podocyte Injury in Diabetic Mice.

[This retracts the article DOI: 10.1155/2022/9018379.].

Genetic Mechanism of Tissue-Specific Expression of PPAR Genes in Turbot (Scophthalmus maximus) at Different Temperatures.

In this study, we used PCR to measure the levels of the peroxisome proliferator activated receptor genes PPARα1, PPARα2, PPARβ, and PPARγ in the intestine, liver, gill, heart, kidney, brain, muscle, spleen, skin, and stomach of turbot (Scophthalmus maximus) cultured under different temperature conditions (14, 20, 23, 25, and 28 °C). We used split-split-plot (SSP) analysis of variance, additive main effects and multiplicative interaction (AMMI) analysis, and genotype main effects and genotype × environment interaction (GGE) biplot analysis to evaluate the genotype × tissue interaction effects on gene expression. The results of the SSP analysis of variance showed that temperature and tissue × gene have highly significant (p < 0.01) effect on the expression of S. maximus PPAR genes. The AMMI analysis results revealed that the expression of PPAR genes at the appropriate temperature (14 °C) mainly depended on genotype × tissue interaction and tissue effects. Under stress temperatures, genotype effects, tissue effects, and genotype × tissue interaction, all had significant effects on the expression of PPAR genes. The contribution of the genotype effect slowly increased with increasing temperature; it increased faster at 20 °C and then slowly declined at 25 °C. The contribution of the tissue effect slowly increased from 14 to 20 °C, where it sharply decreased, and then it stabilized after a slight fluctuation. The contribution of the genotype × tissue interaction effect showed a fluctuating upward trend throughout the experiment, and it had a significant impact on PPAR gene expression. The key temperature at which the three effects changed was 20 °C, indicating that it is the limit temperature for active lipid metabolism under high-temperature stress. The GGE biplot analysis results showed that under suitable water temperature, the expression difference of PPAR genes in the liver was the largest; at 20 and 23 °C, the expression difference in the gill was the largest; and at 25 and 28 °C, the expression difference in the brain was the largest. Overall, our results suggest that the mechanism responsible for PPAR gene expression under the three high temperatures (23, 25, and 28 °C) was relatively consistent, but it differed from that at 20 °C.

Peroxisome Proliferator-Activated Receptor Gene Knockout Promotes Podocyte Injury in Diabetic Mice

Objective To investigate the effects of peroxisome proliferator-activated receptor (PPARγ) expression on renal podocyte in diabetic mice by conditionally knockout mouse PPARγ gene. Methods Wild-type C57BL mice and PPARγ gene knockout mice were used as research objects to establish the diabetic mouse model, which was divided into normal control group (NC group), normal glucose PPARγ gene knockout group (NK group), diabetic wild-type group (DM group), and diabetic PPARγ gene knockout group (DK group), with 8 mice in each group. After 16 weeks, the mice were sacrificed for renal tissue collection. Morphological changes of renal tissue were observed by HE and Masson staining, and ultrastructure of renal tissue was observed by transmission electron microscope. Protein expressions of PPARγ, podocin, nephrin, collagen IV, and fibronectin (FN) in renal tissues were detected by immunohistochemistry and Western blot, and mRNA changes of PPARγ, podocin, and nephrin in renal tissues were detected by qRT-PCR. Results Compared with the NC group, the protein and mRNA expressions of PPARγ, podocin, and nephrin decreased in the kidney tissue of mice in the DM group, while the protein expressions of collagen IV and FN increased. The expression of various proteins in kidney tissues of the DK group was consistent with that of the DM group, and the difference was more obvious. The expression of PPARγ protein and mRNA decreased in the NK group, while the expression of podocin, nephrin protein and mRNA, collagen IV, and FN protein showed no significant difference. Conclusion In diabetic renal tissue, the loss of PPARγ can aggravate podocellular damage and thus promote the occurrence of diabetic renal fibrosis. Increasing the expression of PPARγ may effectively relieve renal podocyte impairment in diabetic patients, which can be used for the treatment of diabetic nephropathy.

Effects of active, inactive, and derivatives of Akkermansia muciniphila on the expression of the endocannabinoid system and PPARs genes

This study aimed to investigate the effects of active and heat-inactivated forms of Akkermansia muciniphila, bacterium-derived outer membrane vesicles (OMVs), and cell-free supernatant on the transcription of endocannabinoid system (ECS) members, including cannabinoid receptors 1 and 2 (CB1 and CB2), fatty acid amide hydrolase (FAAH), and peroxisome proliferator-activated receptors (PPARs) genes (i.e., α, β/δ, and δ) in Caco-2 and HepG-2 cell lines. After the inoculation of A. muciniphila in brain heart infusion enriched medium, OMVs and cell-free supernatant were extracted. For the investigation of the effects of bacteria and its derivatives on the expression of ECS and PPARs genes, the aforementioned cells were treated by active and heat-inactivated bacteria, OMVs, and cell-free supernatant. Quantitative real-time polymerase chain reaction analysis revealed that both forms of the bacterium, bacterial-derived OMVs, and cell-free supernatant could affect the expression of CB1, CB2, FAAH, and PPARs genes (i.e., α, β/δ, and δ) significantly (P < 0.05). Considering the engagement of the aforementioned genes in metabolic pathways, it might be suggested that both forms of the bacterium, OMVs, and cell-free supernatant might have the potential to serve as a probiotic, paraprobiotic, and postbiotic candidate to prevent obesity, metabolic disorders, and liver diseases.

Molecular-genetic characteristics of patients with diabetes mellitus. Vestsi Natsyyanal’nai akademii navuk Belarusi

The article discusses the prospects for studying polymorphic variants of peroxisome proliferator-activated receptor genes (PPARs) of three types (PPARα, PPARδ, and PPARγ) in diabetes mellitus (DM), taking into account their key role in the regulation of energy homeostasis, production of pro-inflammatory cytokines, and lipid characteristics and glycemia control. The main emphasis is on the use of screening methods for testing patients for carriage of single nucleotide polymorphisms (SNPs) in order to improve approaches to identifying risk groups for the formation of DM and associated diseases, and subsequent personification of corrective measures. The clinical, laboratory and molecular genetic characteristics of groups of patients with type 1 and 2 diabetes, healthy volunteers are presented. The prevalence of SNPs in the genes of receptors activated by the peroxisome proliferator in patients with DM was studied in comparison with the control group. Among the evaluated SNPs of the rs135551 gene, PPARA showed the clearest association with the presence of DM. Four variants of haplotypes highly associated with DM1 and DM2 were identified. The expediency of further clarification of the clinical and genetic heterogeneity of cases of diabetes within the DM1 and DM2 groups is discussed. The prospects of this direction for the development of preventive technologies in diabetology, long-term epidemiological molecular genetic screenings are assessed.

Screening and functional validation of lipid metabolism-related lncRNA-46546 based on the transcriptome analysis of early embryonic muscle tissue in chicken.

The study was conducted to screen differentially expressed long noncoding RNA (lncRNA) in chickens by high-throughput sequencing and explore its mechanism of action on intramuscular fat deposition. Herein, Rose crown and Cbb broiler chicken embryo breast and leg muscle lncRNA and mRNA expression profiles were constructed by RNA sequencing. A total of 96 and 42 differentially expressed lncRNAs were obtained in Rose crown vs Cobb broiler chicken breast and leg muscle, respectively. lncRNA-ENSGALT00000046546, with high interspecific variability and a potential regulatory role in lipid metabolism, and its predicted downstream target gene 1-acylglycerol-3-phosphate-O-acyltransferase 2 (AGPAT2), were selected for further study on the preadipocytes. lncRNA-46546 overexpression in chicken preadipocyte 2 cells significantly increased (p<0.01) the expression levels of AGPAT2 and its downstream genes diacylglycerol acyltransferase 1 and diacylglycerol acyltransferase 2 and those of the fat metabolism-related genes peroxisome proliferator-activated receptor γ, CCAAT/enhancer binding protein α, fatty acid synthase, sterol regulatory element-binding transcription factor 1, and fatty acid binding protein 4. The lipid droplet concentration was higher in the overexpression group than in the control cells, and the triglyceride content in cells and medium was also significantly increased (p<0.01). This study preliminarily concludes that lncRNA-46546 may promote intramuscular fat deposition in chickens, laying a foundation for the study of lncRNAs in chicken early embryonic development and fat deposition.

Oxysterol-Binding Protein-Like 3 is a Novel Target Gene of Peroxisome Proliferator-Activated Receptor γ In Fatty Liver Disease

Oxysterol-Binding Protein-Like 3 is a Novel Target Gene of Peroxisome Proliferator-Activated Receptor γ In Fatty Liver Disease

Therapeutic Targeting of PPAR Signaling in Cancer Treatment-Related Lymphedema

Lymphedema secondary to cancer treatment affects up to 1 in 5 cancer survivors. It is an irreversible late normal tissue toxicity characterized by swelling and scar formation (fibrosis) of the affected limb with physical and psychosocial health consequences for patients. Recent evidence reveals changes in peroxisome proliferator-activated receptor (PPAR) signaling as an underlying pathology of this disease. PPAR agonists have demonstrated therapeutic benefit in other fibrotic conditions; their role in lymphedema, however, remains unclear.In this study, RNA-sequencing of human and murine tissues with and without lymphedema was performed. Samples included: human lymphedema (n = 4), human normal tissue control (n = 5, matched for demographics and cancer history), murine lymphedema (n = 12), and murine control (n = 9). Pathway enrichment analysis was performed. An in vitro model of lymphedema fibrosis using cultured transforming growth factor beta (TGFβ)-stimulated fibroblasts and an in vivo model of lymphedema using a murine surgical model of tail lymphedema were utilized to evaluate the effects of PPAR agonists on gene expression and fibrotic protein expression (pro-collagen Iα1, collagen) in lymphedema compared to controls.RNA-sequencing of tissue from human and murine lymphedema and control subjects identified that suppression of PPAR signaling was a hallmark of lymphedema fibrosis on pathway enrichment analysis (FDR < 0.01). In the murine model, PPAR signaling gene expression changes co-occurred with fibrotic deposition beginning as early as two weeks after lymphedema development, and continued for at least 35 weeks. Treatment of TGFβ-stimulated fibroblasts with a PPAR agonist resulted in an increase in expression of PPAR genes and suppression of COL1α1 gene expression (n≥9 per group, q < 0.05) as well as reduction in the secretion of fibrotic proteins: pro-collagen Iα1 on ELISA (n≥8 per group, P < 0.0001) and collagen I on Western blotting. PPAR agonist treatment of the murine model of lymphedema resulted in a significant reduction in lymphedema fibrosis as measured by trichrome collagen staining (n≥4 per group, P < 0.05).These data, for the first time, demonstrated the value of upregulating PPAR signaling to treat lymphedema. For this condition, which to date, has no cure, repurposing PPAR agonists for lymphedema treatment is a highly promising therapeutic opportunity, which warrants further investigation.

[Analysis of sepsis-related genes through weighted gene co-expression network].

To identify the Key genes in the development of sepsis through Weighted Gene Co-Expression Network Analysis (WGCNA). The gene expression dataset GSE154918 was downloaded from the public database Gene Expression Omnibus (GEO) database, which containes data from 105 microarrays of 40 control cases, 12 cases of asymptomatic infection, 39 cases of sepsis, and 14 cases of follow-up sepsis. The R software was used to screen out differentially expressed genes (DEG) in sepsis, and the Distributed Access View Integrated Database (DAVID), SEARCH TOOL FOR RETRIEVAL OF INTERACTING NEIGHBOURING GENES (STRING) and visualization software Cytoscape were used to perform gene function and pathway enrichment analysis, Protein-protein interaction (PPI) network analysis and key gene analysis to screen out the key genes in the development of sepsis. Forty-six candidate genes were obtained by WGCNA and combined with DEG expression analysis, and these 46 genes were analyzed by gene ontology (GO) and Kyoto City Encyclopedia of Genes and Genomes (KEGG) pathway enrichment to obtain gene functions and involved signaling pathways. The PPI network was further constructed using the STRING database, and 5 key genes were selected by the PPI network visualization software Cytoscape, including the mast cell expressed membrane protein 1 gene (MCEMP1), the S100 calcium-binding protein A12 gene (S100A12), the adipokine resistance factor gene (RETN), the c-type lectin structural domain family 4 member gene (CLEC4D), and peroxisome proliferator-activated receptor gene (PPARG), and differential expression analysis of each of these 5 genes showed that the expression levels of the above 5 genes were significantly upregulated in sepsis patients compared with healthy controls. In this study, 5 key genes related to sepsis were screened by constructing WGCNA method, which may be potential candidate targets related to sepsis diagnosis and treatment.

Paternal trans-fatty acid and vitamin E diet affects rat offspring's semen quality and PPARs expression.

Trans-fatty acids (TFAs) consumption has created concerns regarding male/female reproductive system. However, the effects of TFA in paternal diet on offspring's reproduction have not been addressed. The purpose of this study is to investigate the effects of rat paternal TFAs and vitamin E consumption on offspring's sperm quality and expression pattern of peroxisome proliferator-activated receptors (PPARs) in testis tissues. Forty adult male rats were randomly divided into four groups: Control diet (C); Control diet plus TFA (CTH); diet supplemented with vitamin E (E) and a diet containing vitamin E and TFA (ETH). Mother rats had normal diet during gestation period. Three offspring from each group were chosen randomly and their testicular samples were collected, and sperm parameters were measured by CASA. Our results indicate that feeding fathers with TFA can negatively affect offspring's sperm concentration and motility, while consumption of vitamin E can improve these parameters (p<.05). The paternal diet containing TFA down-regulated the expression of PPARβ and PPARγ genes, whereas vitamin E-containing diet up-regulated the transcription of PPAR genes. In conclusion, TFA intake in paternal diet may have negative effects on reproductive system of the offspring while vitamin E may not diminish these effects.