Receptor Gamma Research Articles

OroxylinA exerts anticancer effects on human ovarian cancer cells via the PPARγ‑dependent reversal of the progesterone receptor membrane component 1/2 expression profile.

Ovarian cancer is the most lethal gynecological cancer worldwide. To date, the therapeutic approaches available for the treatment of ovarian cancer are still very limited. The present study first demonstrated that the Chinese herb, Oroxylin A, exerts inhibitory effects on both the migratory ability and viability of ovarian cancer cells. Notably, the inhibitory effects of the drug occurred in a dose‑dependent manner. Oroxylin A only inhibited cell migration at the lower dose, whereas it induced early or late apoptosis at the middle or higher doses, respectively. Mechanistically, Oroxylin A increased peroxisome proliferator‑activated receptor gamma (PPARγ) expression and altered the expression profile of progesterone receptor membrane component (PGRMC)1/2. Notably, PPARγ was revealed to play a central role in Oroxylin A‑mediated anticancer activity. The silencing of PPARγ significantly abrogated Oroxylin A‑induced apoptotic cell death and restored the expression profile of the PGRMC1/2 family in ovarian cancer cells. Collectively, the present study revealed that Oroxylin A exerted marked anticancer effects against ovarian cancer in vitro. Thus, Oroxylin A may have potential for use as a complementary therapy in the treatment of ovarian cancer.

A putative role for the aryl hydrocarbon receptor (AHR) gene in a patient with cyclical Cushing\u2019s disease

BackgroundApart from PRKAR1A mutations in a subset of cyclical Cushing’s syndrome due to primary pigmented nodular adrenocortical disease, the molecular basis of cyclical Cushing’s syndrome has not been investigated. We speculated that cyclical Cushing’s syndrome may be due to mutations in the clock genes that govern circadian rhythms, including the hypothalamic-pituitary-adrenal axis.Case presentationA 47-year-old man presented with mass effects from a sellar lesion. He was ultimately diagnosed with cyclical Cushing’s disease due to a giant corticotrophinoma. We performed whole exome sequencing of germline and tumour DNA, SNP array of tumour DNA and tumour immunohistochemistry in order to detect variants in candidate circadian/pituitary-associated genes. We identified a rare germline missense variant in the aryl hydrocarbon receptor (AHR) gene, which has previously been indirectly linked to pituitary tumorigenesis and clock system disruption. The AHR variant was found in a highly conserved site involved in phosphorylation. It was predicted to be damaging by multiple in silico tools and AHR tumour immunohistochemistry demonstrated loss of the normal nuclear staining pattern, suggestive of an inactivating mutation. We also found a novel, damaging germline missense variant in the retinoid X receptor gamma (RXRG) gene, multiple somatic chromosomal gains (including AHR), and a somatic mutational signature consistent with oncogenesis that may have acted synergistically with the AHR variant.ConclusionsThis is the first report of an AHR variant with predicted pathogenicity in the pituitary adenoma setting. Our preliminary data suggest that the highly conserved AHR gene may represent a link between pituitary tumorigenesis, the hypothalamic-pituitary-adrenal axis and the clock system. Further research may indicate a role for the gene in the development of cyclical Cushing’s disease.

PPARγ Deficiency in Carbon Nanotube-elicited Granulomatous Inflammation Promotes a Th17 Response to a Microbial Antigen

BackgroundThe pathological consequences of interaction between environmental carbon pollutants and microbial antigens have not been fully explored. We developed a murine model of multi-wall carbon nanotube (MWCNT)-elicited granulomatous disease which bears a striking resemblance to sarcoidosis, a human granulomatous disease. Because of reports describing lymphocyte reactivity to mycobacterial antigens in sarcoidosis patients, we hypothesized that addition of mycobacterial antigen (ESAT-6) to MWCNT might elicit activation in T cells.MethodsMacrophage-specific peroxisome-proliferator-activated receptor gamma (PPARγ) knock out (KO) mice were studied along with wild-type mice because our previous report indicated PPARγ deficiency in sarcoidosis alveolar macrophages. MWCNT+ESAT-6 were instilled into mice. Controls received vehicle (surfactant-PBS) or ESAT-6 and were evaluated 60 days post-instillation. As noted in our recent publication, lung tissues from PPARγ KO mice instilled with MWCNT+ESAT-6 yielded more intensive pathophysiology, with elevated fibrosisResultsInspection of mediastinal lymph nodes (MLN) revealed no granulomas but deposition of MWCNT. MLN cell counts were higher in PPARγ KO than in wild-type instilled with MWCNT+ESAT-6. Moreover, the CD4:CD8 T cell ratio, a major clinical metric for human disease, was increased in PPARγ KO mice. Bronchoalveolar lavage (BAL) cells from PPARγ KO mice instilled with MWCNT+ESAT-6 displayed increased Th17 cell markers (RORγt, IL-17A, CCR6) which associate with elevated fibrosis.ConclusionThese findings suggest that PPARγ deficiency in macrophages may promote ESAT-6-associated T cell activation in the lung, and that the MWCNT+ESAT-6 model may offer new insights into pathways of lymphocyte-mediated sarcoidosis histopathology.

Transthyretin Maintains Muscle Homeostasis Through the Novel Shuttle Pathway of Thyroid Hormones During Myoblast Differentiation.

Skeletal muscle, the largest part of the total body mass, influences energy and protein metabolism as well as maintaining homeostasis. Herein, we demonstrate that during murine muscle satellite cell and myoblast differentiation, transthyretin (TTR) can exocytose via exosomes and enter cells as TTR- thyroxine (T4) complex, which consecutively induces the intracellular triiodothyronine (T3) level, followed by T3 secretion out of the cell through the exosomes. The decrease in T3 with the TTR level in 26-week-old mouse muscle, compared to that in 16-week-old muscle, suggests an association of TTR with old muscle. Subsequent studies, including microarray analysis, demonstrated that T3-regulated genes, such as FNDC5 (Fibronectin type III domain containing 5, irisin) and RXRγ (Retinoid X receptor gamma), are influenced by TTR knockdown, implying that thyroid hormones and TTR coordinate with each other with respect to muscle growth and development. These results suggest that, in addition to utilizing T4, skeletal muscle also distributes generated T3 to other tissues and has a vital role in sensing the intracellular T4 level. Furthermore, the results of TTR function with T4 in differentiation will be highly useful in the strategic development of novel therapeutics related to muscle homeostasis and regeneration.

Restoration of myocellular copper-trafficking proteins and mitochondrial copper enzymes repairs cardiac function in rats with diabetes-evoked heart failure.

Diabetes impairs systemic copper regulation, and acts as a major independent risk factor for heart failure (HF) wherein mitochondrial dysfunction is a key pathogenic process. Here we asked whether diabetes might alter mitochondrial structure/function and thus impair cardiac performance by damaging myocellular pathways that mediate cell-copper homeostasis. We measured activity of major mitochondria-resident copper-enzymes cytochrome c oxidase (mt-Cco) and superoxide dismutase 1 (mt-Sod1); expression of three main mitochondrial copper-chaperones [Cco copper chaperone 17 (Cox17), Cox11, and mitochondria-resident copper chaperone for Sod1 (mt-Ccs)]; of copper-dependent Cco-assembly protein Sco1; and regulation of mitochondrial biogenesis, in left-ventricular (LV) tissue from groups of non-diabetic-control, untreated-diabetic, and divalent-copper-selective chelator-treated diabetic rats. Diabetes impaired LV pump function; ∼halved LV-copper levels; substantively decreased myocellular expression of copper chaperones, and enzymatic activity of mt-Cco and mt-Sod1. Divalent-copper chelation with triethylenetetramine improved cardiac pump function, restored levels of myocardial copper, the copper chaperones, and Sco1; and enzymatic activity of mt-Cco and mt-Sod1. Copper chelation also restored expression of the key mitochondrial biogenesis regulator, peroxisome-proliferator-activated receptor gamma co-activator-1α (Pgc-1α). This study shows for the first time that altered myocardial copper-trafficking is a key pathogenic process in diabetes-evoked HF. We also describe a novel therapeutic effect of divalent-copper-selective chelation, namely restoration of myocellular copper trafficking, which is thus revealed as a potentially tractable target for novel pharmacological intervention to improve cardiac function.

Clinical Factors and Cellular Responses of In Situ Human Alveolar Bone-Derived Mesenchymal Stromal Cells Associated With Early Periimplant Marginal Bone Loss: A Prospective Cohort Pilot Study.

To investigate clinical factors and cellular responses of in situ human alveolar bone-derived mesenchymal stromal cells involved in early periimplant marginal bone loss. Thirty-seven completely or partially edentulous patients were enrolled in this study. Periapical radiographs were taken at the time of implant surgery, at 3-month follow-up, and at 1-year follow-up. Univariate analysis and multiple logistic regression were performed to investigate the associations between marginal bone loss and study variables. The mRNA expression levels of 21 bone-remodeling- and tissue-healing-associated genes were analyzed by subgroup. Thirty-one patients with 98 implants were followed. The incidence and mean amount of bone loss were higher for overdentures than for other prosthesis and higher for the maxilla than for the mandible. The bone loss group showed lower mRNA expression levels of runt-related transcription factor-2, bone morphogenetic protein-2, and peroxisome proliferator-activated receptor gamma-2 and higher receptor activator of NKκB ligand/osteoprotegerin (RANKL/OPG) ratio. Within the limitations of the study, certain genes involved in bone remodeling (runt-related transcription factor-2 [Runx-2], bone morphogenetic protein-2 [BMP-2], and peroxisome proliferator-activated receptor gamma-2 [PPARγ-2]) and RANKL/OPG are correlated with early periimplant bone loss, with the type of suprastructure and the involved jaw being significant clinical factors.

Retinoid X receptor gamma (RXRG) is an independent prognostic biomarker in ER-positive invasive breast cancer

BackgroundRetinoid X Receptor Gamma (RXRG) is a member of the nuclear receptor superfamily and plays a role in tumour suppression. This study aims to explore the prognostic significance of RXRG in breast cancer.MethodsPrimary breast cancer tissue microarrays (n = 923) were immuno-stained for RXRG protein and correlated with clinicopathological features, and patient outcome.ResultsNuclear RXRG expression was significantly associated with smaller tumour size (p = 0.036), lower grade (p < 0.001), lobular histology (p = 0.016), lower Nottingham Prognostic Index (p = 0.04) and longer breast cancer-specific survival (p < 0.001), and longer time to distant metastasis (p = 0.002). RXRG expression showed positive association with oestrogen receptor (ER)-related biomarkers: GATA3, FOXA1, STAT3 and MED7 (all p < 0.001) and a negative correlation with the Ki67 proliferation marker. Multivariate analysis demonstrated RXRG protein as an independent predictor of longer breast cancer-specific survival and distant metastasis-free survival. In the external validation cohorts, RXRG expression was associated with improved patients’ outcome (p = 0.025). In ER-positive tumours, high expression of RXRG was associated with better patient outcome regardless of adjuvant systemic therapy. ER signalling pathway was the top predicted master regulator of RXRG protein expression (p = 0.005).ConclusionThis study provides evidence for the prognostic value of RXRG in breast cancer particularly the ER-positive tumours.

The Expression of CNS-Specific PPARGC1A Transcripts Is Regulated by Hypoxia and a Variable GT Repeat Polymorphism

PPARGC1A encodes a transcriptional co-activator also termed peroxisome proliferator-activated receptor (PPAR) gamma coactivator 1-alpha (PGC-1α) which orchestrates multiple transcriptional programs. We have recently identified CNS-specific transcripts that are initiated far upstream of the reference gene (RG) promoter. The regulation of these isoforms may be relevant, as experimental and genetic studies implicated the PPARGC1A locus in neurodegenerative diseases. We therefore studied cis- and trans-regulatory elements activating the CNS promoter in comparison to the RG promoter in human neuronal cell lines. A naturally occurring variable guanidine thymidine (GT) repeat polymorphism within a microsatellite region in the proximal CNS promoter increases promoter activity in neuronal cell lines. Both the RG and the CNS promoters are activated by ESRRA, and the PGC-1α isoforms co-activate ESRRA on their own promoters suggesting an autoregulatory feedback loop. The proximal CNS, but not the RG, promoter is induced by FOXA2 and co-activated by PGC-1α resulting in robust activation. Furthermore, the CNS, but not the RG, promoter is targeted by the canonical hypoxia response involving HIF1A. Importantly, the transactivation by HIF1A is modulated by the size of the GT polymorphism. Increased expression of CNS-specific transcripts in response to hypoxia was observed in an established rat model, while RG transcripts encoding the full-length reference protein were not increased. These results suggest a role of the CNS region of the PPARGC1A locus in ischemia and warrant further studies in humans as the activity of the CNS promoter as well as its induction by hypoxia is subject to inter-individual variability due to the GT polymorphism.

EGFR/ErbB Inhibition Promotes OPC Maturation up to Axon Engagement by Co-Regulating PIP2 and MBP.

Remyelination in the adult brain relies on the reactivation of the Neuronal Precursor Cell (NPC) niche and differentiation into Oligodendrocyte Precursor Cells (OPCs) as well as on OPC maturation into myelinating oligodendrocytes (OLs). These two distinct phases in OL development are defined by transcriptional and morphological changes. How this differentiation program is controlled remains unclear. We used two drugs that stimulate myelin basic protein (MBP) expression (Clobetasol and Gefitinib) alone or combined with epidermal growth factor receptor (EGFR) or Retinoid X Receptor gamma (RXRγ) gene silencing to decode the receptor signaling required for OPC differentiation in myelinating OLs. Electrospun polystyrene (PS) microfibers were used as synthetic axons to study drug efficacy on fiber engagement. We show that EGFR inhibition per se stimulates MBP expression and increases Clobetasol efficacy in OPC differentiation. Consistent with this, Clobetasol and Gefitinib co-treatment, by co-regulating RXRγ, MBP and phosphatidylinositol 4,5-bisphosphate (PIP2) levels, maximizes synthetic axon engagement. Conversely, RXRγ gene silencing reduces the ability of the drugs to promote MBP expression. This work provides a view of how EGFR/ErbB inhibition controls OPC differentiation and indicates the combination of Clobetasol and Gefitinib as a potent remyelination-enhancing treatment.

Circulating miR-130 and its target PPAR-γ may be potential biomarkers in patients of coronary artery disease with type 2 diabetes mellitus.

BackgroundPatients of coronary artery disease (CAD) with type 2 diabetes mellitus (DM2) show increased mortality risk than CAD patients without DM2, while few biomarkers can be used to discriminate them.MethodsFifty‐nine patients of CAD with DM2 (DM2‐CAD group), 79 patients of CAD without DM2 (CAD group), and 63 healthy control subjects were recruited. Circulating miR‐130 (miR‐130a and miR‐130b) and PPAR‐γ (peroxisome proliferator‐activated receptor gamma) were measured and their Pearson correlation was analyzed. 3′ UTR binding prediction and luciferase assay were used to determine the target relationship between miR‐130 and PPAR‐γ. Receiver operating characteristics (ROC) analysis was performed to test the discrimination ability of miR‐130 between DM2‐CAD and CAD groups.ResultsmiR‐130a and miR‐130b showed decreased expression in DM2‐CAD group when compared with the CAD group and health control. Both bioinformatics and luciferase assays showed that miR‐130 could bind the 3′ UTR of PPAR‐γ. Furthermore, miR‐130 negatively correlated with PPAR‐γ in both CAD and DM2‐CAD group in Pearson's coefficient analysis. Both miR‐130a and miR‐130b were able to discriminate DM2‐CAD group from CAD group and control subjects.ConclusionCirculating miR‐130 may regulate the expression of PPAR‐γ and can be used as a biomarker to discriminate DM2‐CAD from CAD.

PGC-1α, a potential therapeutic target against kidney aging.

Aging is defined as changes in an organism over time. The proportion of the aged population is markedly increasing worldwide. The kidney, as an essential organ with a high energy requirement, is one of the most susceptible organs to aging. It is involved in glucose metabolism via gluconeogenesis, glucose filtration and reabsorption, and glucose utilization. Proximal tubular epithelial cells (PTECs) depend on lipid metabolism to meet the high demand for ATP. Recent studies have shown that aging‐related kidney dysfunction is highly associated with metabolic changes in the kidney. Peroxisome proliferator‐activated receptor gamma coactivator‐1 alpha (PGC‐1α), a transcriptional coactivator, plays a major role in the regulation of mitochondrial biogenesis, peroxisomal biogenesis, and glucose and lipid metabolism. PGC‐1α is abundant in tissues, including kidney PTECs, which demand high energy. Many in vitro and in vivo studies have demonstrated that the activation of PGC‐1α by genetic or pharmacological intervention prevents telomere shortening and aging‐related changes in the skeletal muscle, heart, and brain. The activation of PGC‐1α can also prevent kidney dysfunction in various kidney diseases. Therefore, a better understanding of the effect of PGC‐1α activation in various organs on aging and kidney diseases may unveil a potential therapeutic strategy against kidney aging.

Correlations of PPARα and PPARγ expressions with 1H-MRS quantified hepatic fat content in pups of rats that experienced intrauterine growth restriction

Background: Proton magnetic resonance spectroscopy (1H-MRS) measurement of hepatic fat content in intrauterine growth restriction rats has rarely been reported. This study was to explore the association of peroxisome proliferator-activated receptor alpha and gamma (PPARα and PPARγ) expression with 1H-MRS quantified hepatic fat content in offspring of rats that experienced intrauterine growth restriction (IUGR).Methods and findings: IUGR was established by feeding a low-protein diet to female rats during pregnancy. Male pups of IUGR rats were weighed, liver tissues were collected at the ages of 1 day and 1, 3, 8 and 12 weeks post birth. Visceral adipose tissues (VATs) were collected at 3, 8, and 12 weeks post birth. Male pups also received conventional magnetic resonance imaging and 1H-MRS using a 3.0 T whole-body MR scanner at 3, 8, and 12 weeks post birth. The peak area ratios in the MR spectra were calculated to determine hepatic lipid content. The expression of PPARα protein was detected by Western blot. The expression of PPARα mRNA was measured by real-time quantitative PCR. Significantly lower PPARα protein and mRNA expression were observed in liver tissues of male pups of IUGR rats at 1 day and 1, 3, 8, and 12 weeks post birth compared to male pups of control rats. In contrast, significantly higher PPARγ protein and mRNA expression were observed in VATs of male pups of IUGR rats at 3, 8, and 12 weeks post birth compared to male pups of control rats. PPARα protein and mRNA expression in the liver negatively correlated with the hepatic fat content (r = −0.611, −0.607, respectively), whereas PPARγ protein and mRNA expression in VATs positively correlated with the hepatic fat content (r = 0.659, 0.668, respectively).Conclusion: 1H-MRS allows noninvasive assessment of hepatic fat content in rats. PPARα protein and mRNA expression were significantly decreased in the livers of rats, whereas PPARγ protein and mRNA expression was significantly increased in VATs in pups of IUGR rats.

ESRRG promoter hypermethylation as a diagnostic and prognostic biomarker in laryngeal squamous cell carcinoma.

BackgroundEstrogen‐related receptor gamma (ESRRG) has been identified as a tumor suppressor gene in several cancers. We aimed to evaluate ESRRG promoter methylation in laryngeal squamous cell carcinoma (LSCC) and its relative clinical value in LSCC.MethodsBisulfite pyrosequencing assays were performed on 91 pairs of tumor and paracancer tissues from LSCC patients in China. The diagnostic value and overall survival (OS) were analyzed descriptively by receiver operating characteristic (ROC) curves and the Kaplan‐Meier methods, respectively.ResultsThe ESRRG promoter was more frequently hypermethylated in tumor tissues than in adjacent tissues (P < 0.01). ESRRG promoter methylation was significantly increased in advanced T stage tumors (P < 0.01) and advanced clinical stage patients (P < 0.01). Moreover, the area under the ROC curve (AUC) value (0.81) indicated high discrimination accuracy. Furthermore, ESRRG hypermethylation was associated with poor OS, as confirmed by Kaplan‐Meier survival curves (P < 0.01).ConclusionOur study indicated that ESRRG promoter hypermethylation contributed to LSCC‐related risks, primarily tumor progression and survival prognosis, in patients. ESRRG promoter methylation could, therefore, be a diagnostic and prognostic biomarker in LSCC.

PPARγ/ETV2 Regulate Endothelial‐to‐Mesenchymal Transition in the Hypoxia/Sugen Rat Model of Pulmonary Hypertension

RationalePulmonary hypertension (PH) is a chronic cardiopulmonary disorder that causes significant morbidity and mortality. Endothelial‐to‐mesenchymal transition(EndoMT) plays an important role in initiation and progression of PH, suggesting that EndoMT may be a novel and effective therapeutic target in PH. However, the molecular mechanisms regulating EndoMT and how they promote PH remains largely unknown. Our lab and others have established the importance of peroxisome proliferator‐activated receptor gamma (PPARγ) in PH. Our studies indicate that PPARγ regulates the transcription factor, ETS variant 2 (ETV2), which is in dispensable for cardiovascular system development and serves as a master regulator for endothelial cell generation and function. Thus, we hypothesize that the PPARγ/ETV2 axis regulates EndoMT in PH.MethodsMale Sprague Dawley rats received a single injection of Sugen 5416 (SU, 20 mg/kg) followed by exposure to 3 weeks of hypoxia (10% O2) or normoxia(NOR, 21% O2) followed an additional 2 weeks of NOR. Right ventricular systolic pressure (RVSP)and right ventricular hypertrophy (RVH) were measured to confirm PH. To further examine the functional significance of ETV2 in PH, we measured RVSP and RVH in ETV2+/− mice. Levels of EndoMT markers in lungs of HYP/SU rats or ETV2+/− mice were compared to NOR/SU rats or wild‐typemice using qRT‐PCR and Western blot analysis. An ETV2 promoter activity assay was used to determine if PPARγ transcriptionally regulates ETV2 expression. Further, to determine if PPARg or ETV2 signaling regulates the levels of EndoMT markers, PPARγ or ETV2 loss or gain of function strategies were employed. To model in vivo EndoMT in PH, induced‐EndoMT (i‐EndoMT) cells were induced by treating human pulmonaryartery endothelial cells (HPAECs) with IL1β, TNFα, and TGFβ, and then examined functional alterations using collagen cell contraction and wound healing assays.ResultsAs expected, HYP/SU treatment and ETV2+/− mice resulted in PH. HYP/SU treatment and ETV2+/− mice also increased lung levels of mesenchymal markers, including desmin, TGFβ1, SLUG, and αSMA. Luciferase‐promoter assays showed that PPARγ transcriptionally activates the ETV2 promoter. HPAECs lost cobblestone morphology to a more elongeted, spindle‐shaped myofibroblastic cell morphology, indication the activation of EndoMT. I‐EndoMT cells significantly enhanced basal cellular contraction and migratory response compared with HPAECs. Levels of PPARγ and ETV2 were decreased in i‐EndoMT cells whereas markers of EndoMT were increased. Importantly, knockdown of PPARγ or ETV2 in HPAEC increased levels of EndoMT markers whereas overexpression of PPARγ/ETV2 axis led to reduced expression of EndoMT markers.ConclusionsCollectively, these studies establish that the PPARγ/ETV2 axis contributes to regulation of EndoMT and maythere by participate in the pathogenesis of PH. These findings suggest novel molecular pathways involved in EndoMT and PH pathogenesis that merit further exploration.Support or Funding InformationNIH HL102167 (RLS and CMH), NIH HL119291 (CP), and NIH HL133053 (BYK).This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Structural mechanism of corepressor‐selective inverse agonism of the nuclear receptor PPARγ

The structural mechanisms affording ligand‐induced activation of nuclear receptor transcription factor peroxisome proliferator‐activated receptor gamma (PPARγ) are well understood; however, it remains poorly understood how to design transcriptionally repressive PPARγ inverse agonists. We discovered that a simple phenyl‐to‐pyridyl substitution between two common covalent orthosteric ligands targeting PPARγ converts a transcriptionally neutral antagonist into a corepressor‐selective inverse agonist. Using X‐ray crystallography, molecular dynamics simulations, NMR spectroscopy, and mutagenesis coupled to activity assays, we discovered that hydrogen bond formation with Arg288 is essential for corepressor‐selective inverse agonism. For one corepressor‐selective inverse agonist, NMR spectroscopy revealed that PPARγ exchanges between two long‐lived conformations, including a conformation that prepopulates a corepressor‐bound state that primes PPARγ for high affinity corepressor binding. We also determined the crystal structure of corepressor‐bound PPARγ, which reveals several unique conformational features compared to the well studied active conformation. Our findings define new structural features for repressing PPARγ transcription with ligands.Support or Funding InformationThis work was supported by National Institutes of Health (NIH) grants R01DK101871, F32DK108442; and American Heart Association (AHA) award 16POST27780018 (RB)This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Changes in Adipose Tissue Physiology during the First Two Weeks Post‐hatch in Chicks from Lines Selected for Low or High Body Weight

Chickens from lines selected for low or high body weight from a common foundation population differ in appetite and adiposity; however, mechanisms associated with the predisposition to becoming obese are unclear. The objective of this study was thus to evaluate developmental changes in depot‐specific adipose tissue during the first 14 days post‐hatch. The subcutaneous (SQ), clavicular (CL) and abdominal (AB) adipose depots were collected for histological and mRNA expression measurements from chicks of each line on day of hatch, day 4 and day 14 post‐hatch. Results showed that low line chicks had decreased SQ fat mass on a body weight basis with reduced adipocyte size from day of hatch to day 4 and increased body weight and fat mass with unchanged adipocyte size from day 4 to day 14 post‐hatch. High line chicks had increased body weight throughout the first 14 days post‐hatch, and increased fat mass in all three depots with significantly enlarged adipocytes in AB from day 4 to day 14 post‐hatch. Meanwhile, mRNA expression of CCAAT/enhancer‐binding protein alpha, neuropeptide Y and peroxisome proliferator‐activated receptor gamma, which are involved in adipogenesis, as well as acyl‐CoA dehydrogenase, long chain, which catalyzes fatty acid oxidation, had different expression patterns among depots between lines at different ages. From day of hatch to day 4 post‐hatch, low line chicks mobilized SQ fat and replenished the reservoir mainly through hyperplasia, whereas in the high line there was dependency on both hyperplasia and hypertrophy to maintain adipocyte size and depot mass. From day 4 to day 14, adipose tissue catabolism and adipogenesis slowed down in both lines. While the fat depot mass and adipocyte size were stable in the low line, there was rapid accumulation of fat in CL and AB regions of high line. Chicks predisposed to be anorexic or obese display different fat development patterns during the early post‐hatch period.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

PPARγ inhibition regulates the cell cycle, proliferation and motility of bladder cancer cells.

Peroxisome proliferator‐activated receptor gamma (PPARγ) is a member of the nuclear receptor family of ligand‐activated transcription factors and plays an important role in regulating cell proliferation, inflammation and lipid and glucose homeostasis. Our results revealed that PPARγ was up‐regulated in human bladder cancer (BCa) tissues both at transcriptional and translational levels. Moreover, down‐regulation of PPARγ mRNA or inhibition of PPARγ function (using GW9662, antagonist of PPARγ) could significantly suppress the proliferation of BCa cells. Furthermore, the cell cycle arrested in G0/G1 phase was also induced by the down‐regulated PPARγ possibly through AKT‐mediated up‐regulation of p21/p27, whereas no significant transformation of apoptosis was observed. In addition, knockdown or inhibition of PPARγ might reduce the invasion and migration of BCa cells by affecting epithelial‐mesenchymal transition‐related proteins through AKT/GSK3β signalling pathway. Additionally, in vivo studies showed that BCa cell proliferation was significantly suppressed by GW9662. In conclusion, our results indicated that PPARγ might be crucial for BCa tumorigenesis by interfering with the motility and viability of BCa cells.

Anti-adipogenesis and antioxidative defense status of a crude extract of 'Kalasin 2' peanut sprouts in 3T3-L1 mouse adipocytes.

The aim of this study was to investigate the effects of extracts from germinated (GPE) and non-germinated peanuts (NGPE) on adipogenesis and oxidative status in normal and oxidative-stress-induced 3T3-L1 mouse adipocytes. The treated cells were analysed for cell growth, lipid accumulation, levels of intracellular reactive oxygen species (ROS), and the expression levels of mRNAs and proteins related to adipogenesis and antioxidative defense systems. The results indicated that an extract from peanuts made 9 days after germination (9GPE) reduced lipid contents and mRNA expression of adipogenesis-related genes to a greater extent than an extract from peanuts made 1-day after germination (1GPE) or from NGPE, respectively. In oxidative-stress-induced adipocytes, 9GPE decreased ROS levels, lipid content, and the protein expression of peroxisome-proliferator-activated receptor gamma, and also increased the protein expression of antioxidants. These results illustrate the anti-adipogenic capacity and oxidative status improvement achievable with GPE, and that it could be used as a putative therapeutic agent in the prevention of and (or) treatment of obesity and diseases associated with oxidative stress.

Protective Function of Mitogen-Activated Protein Kinase Phosphatase 5 in Aging- and Diet-Induced Hepatic Steatosis and Steatohepatitis.

Nonalcoholic fatty liver disease is currently the most common liver disease and is a leading cause of liver‐related morbidity and mortality. However, its pathogenesis remains largely unclear. We previously showed that mice deficient in mitogen‐activated protein kinase (MAPK) phosphatase 5 (MKP5) spontaneously developed insulin resistance and glucose intolerance, which are associated with visceral obesity and adipose tissue inflammation. In this study, we discovered that mice deficient in MKP5 developed more severe hepatic steatosis and steatohepatitis with age or with feeding on a high‐fat diet (HFD) compared to wild‐type (WT) mice, and this was associated with increased expression of proinflammatory cytokines and collagen genes. Increased p38 activation in MKP5 knockout (KO) liver compared to that in WT liver was detected, which contributed to increased expression of lipid droplet‐associated protein cell death‐inducing DFF45‐like effector A (CIDEA) and CIDEC/fat‐specific protein 27 but not CIDEB through activating transcription factor 2 (ATF2). In addition, MKP5 KO liver had higher peroxisome proliferator‐activated receptor gamma (PPARγ) expression compared with WT liver. On the other hand, overexpression of MKP5 or inhibition of p38 activation in hepatocytes resulted in reduced expression of PPARγ. Inhibition of p38 resulted in alleviation of hepatic steatosis in KO liver in response to HFD feeding, and this was associated with reduced expression of CIDEA, CIDEC, and proinflammatory cytokines. Conclusion: MKP5 prevents the development of nonalcoholic steatohepatitis by suppressing p38–ATF2 and p38–PPARγ to reduce hepatic lipid accumulation, inflammation, and fibrosis.

Rational Design and Synthesis of Reversible Covalent PPARγ Antagonistic Ligands Inhibiting Ser273 Phosphorylation

AbstractPeroxisome proliferator‐activated receptor gamma (PPARγ) has been a major therapeutic target for the treatment of type 2 diabetes. However, the use of PPARγ‐targeting drugs such as rosiglitazone and pioglitazone has significantly declined due to adverse effects caused by their classical transcriptional agonism. Meanwhile, blocking the obesity‐induced phosphorylation of PPARγ at Ser273 by Cdk5 has been proposed as the key to developing insulin‐sensitizing effects of PPARγ‐targeting drugs. In this study, we rationally designed and synthesized selective PPARγ phosphorylation inhibitor through a crystal structure‐based approach. During this process, we observed a distinct degradation pattern of the anilinic cyanoacrylamide moiety via the spontaneous retro‐aldol reaction. Thus, we developed a novel reversible covalent inhibitor of PPARγ phosphorylation, SB1495, containing aliphatic cyano‐acrylamide, through systematic structural modification, in silico docking studies, time‐dependent monitoring of stability in aqueous media, and in vitro kinase assay. We also demonstrated its inhibitory activity on PPARγ phosphorylation without classical transactivation in a cellular system as well as in an animal model.