PPARγ Expression Research Articles

Curcumin Modulates the Differential Effects of Fructose and High-Fat Diet on Renal Damage, Inflammation, Fibrosis, and Lipid Metabolism.

Dyslipidemia and obesity hypercaloric diet-induced lead to kidney damage. We investigated the effect of curcumin on the expression of proteins related to inflammation, fibrosis, fatty acids metabolism, kidney damage, and morphological changes in the kidneys of mice hypercaloric diets-fed. Groups of 5-week-old C57BL/6 mice (n=6) were formed: Control (C), High-fructose diet (F), Highfructose diet and curcumin (F+Cur), High-fat diet (HFD), High-fat diet and curcumin (HFD+Cur), High-fat diet and fructose (HFD+F), High-fat diet, fructose and curcumin (HFD+F+Cur), treated for 16 weeks with 30% (w/v) fructose, 60% (w/w) fat and 0.75% (w/w) curcumin. Kidneys were obtained for histomorphological and Western Blot analysis. Curcumin prevented TNF-α overexpression in the F and HFD+F groups. VLCAD expression was higher in the F, HFD, and HFD+F groups. PPARγ expression was lower in the F+Cur, HFD+Cur, and HFD+F+Cur groups. Curcumin prevented overexpression of CPT1 and KIM1 in the HFD+F and HFD groups. Curcumin prevented morphological lesions, fibrosis, and lipid deposition that were hypercaloric diet-induced. Chronic consumption of hypercaloric diets causes inflammation, fibrosis, and lipid deposition in the kidney. It is suggested that curcumin prevents renal structural damage, limits tissue lipid deposition, and differentially modulates renal injury depending on diet composition in mice fed high-fat and/or high-fructose diets.

Preliminary study of the role of histone deacetylase (HDAC) in steroid-induced avascular necrosis of the femoral head induced by BMSC adipogenic differentiation

Our previous research revealed a close association between the acetylation of peroxisome proliferator-activated receptor γ (PPARγ) histone H3K27 and the adipogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). We preliminarily explored the epigenetic mechanism of steroid-induced avascular necrosis of the femoral head (SANFH) development, but the specific histone deacetylase (HDAC) involved in this regulatory process remains unknown. In this study, we combined cell, animal, and clinical specimen experiments to screen for specific HDAC genes that could regulate BMSC adipogenic differentiation and to explore their roles. The results showed that dexamethasone (DEX) significantly exacerbated the imbalance between the adipogenic and osteogenic differentiation of BMSCs, and there were differences in HDAC expression in the adipogenic differentiation cell models, with histone deacetylase 10 (HDAC10) showing the most significant decrease in expression. Subsequent use of a chromatin immunoprecipitation assay kit and quantitative polymerase chain reaction (ChIP‒qPCR) revealed a decrease in HDAC10 expression at predicted potential sites within the PPARγ promoter, indicating a significant decrease in HDAC10 enrichment in the PPARγ promoter region of BMSCs, thereby promoting sustained PPARγ expression. Additionally, immunohistochemistry of samples collected from mice and humans with SANFH and normal femoral heads revealed an imbalance between adipogenic and osteogenic differentiation in the necrotic area of femoral heads, with a significant decrease in the relative expression of HDAC10 in the necrotic area of femoral heads with SANFH. In summary, we speculate that HDAC10 affects the progression of SANFH by regulating BMSC adipogenic differentiation, a process possibly related to PPARγ histone acetylation. These findings provide a promising direction for the treatment of SANFH.Graphical abstract

Study on the Mechanism of Guizhi Fuling Decoction in Treating Hyperlipidemia Based on Network Pharmacology and Experimental Methods

Background Hyperlipidemia, caused by abnormal lipid metabolism, has become a significant health concern, especially in younger populations. While statins are commonly used for treatment, they often cause severe side effects with long-term use, leading to increased interest in finding natural alternatives. Purpose This study aimed to investigate how Guizhi Fuling Decoction (GZFL) treats hyperlipidemia using network pharmacology and experimental validation. Materials and Methods Network pharmacology analyzed GZFL’s active components, targets, and treatment mechanisms for hyperlipidemia. Hyperlipidemia rat and high-fat cell models were established. Experimental validation included enzyme-linked immunosorbent assay, Western blot, quantitative polymerase chain reaction, Oil Red O staining, and other methods. Statistical analysis was performed using one-way analysis of variance followed by Tukey’s post hoc test for multiple comparisons. Pearson correlation analysis was used to identify correlations between key protein expressions and lipid levels. Results GZFL comprises 85 active components and targets 218 proteins. Hyperlipidemia involves 3,852 targets, with 175 overlapping targets. Key targets included estrogen receptor 1, prostaglandin-endoperoxide synthase 2, interleukin-6 (IL-6), protein kinase B (AKT) 1, tumor necrosis factor, interleukin-1 beta, peroxisome proliferator-activated receptor gamma (PPARG), tumor protein p53 (TP53), and fructo oligosaccharide (FOS). Major active components were quercetin, phytosterols, kaempferol, and baicalein. Enrichment analysis highlighted processes like lipopolysaccharide response and lipid signaling pathways. Animal studies showed GZFL significantly reduced serum total cholesterol, triglycerides, and low-density lipoprotein cholesterol levels, and increased apolipoprotein A1 ( p < 0.05). Western blot indicated that GZFL influenced AKT, TP53, IL-6, PPARγ expression, and mRNA levels in the phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) pathway ( p < 0.01). Serum pharmacology experiments demonstrated GZFL-medicated serum reduced lipid droplet formation in high-fat cell models. Conclusion GZFL contains multiple pharmacologically active components, such as quercetin, phytosterols, and kaempferol, which can influence lipid metabolism. It may exert its effects by regulating proteins like AKT, TP53, IL-6, and PPARγ, participating in lipid and atherosclerosis signaling pathways and the PI3K/AKT/mTOR pathway.

Reversal of insulin resistance to combat type 2 diabetes mellitus by newer thiazolidinedione's in fructose induced insulin resistant rats

In our pursuit of discovering new antidiabetic agents to manage type 2 diabetes mellitus (T2DM), our approach aimed to identify the bioactive feature/pharmacophore responsible for PPAR-γ expression, as it is accountable for the glucose homeostasis and lipid metabolism. This was achieved by pharmacophore model generation, screening of rationally designed newer thiazolidinedione's library, identifying synthesizing and characterizing the top ten molecules (5a-5j) for their (Invitro &invivo) antidiabetic activity. Preliminary screening of all the ligands by Invitro glucose uptake assay in L6 myotubes (skeletal muscle cell line of rats) revealed compound 5b and 5f stimulated the glucose uptake with 79.29 ± 1.02 % and 74.58 ± 1.02 % respectively compared to pioglitazone with 82.36 ± 0.98 %. This was validated by PPAR-γ TF expression assay, which highlighted a dose dependent increase in transactivation of PPAR-γ. These compounds 5b and 5f were evaluated in fructose induced insulin resistance rat model. Where the treatment with 5b and 5f markedly increased the exogenous clearance of glucose and exogenous insulin via OGTT and ITT respectively, also improved the glucose utilization by significantly increasing content of glycogen and uptake of glucose in rat hemidiaphragm and reversed insulin resistance. Likewise a significant decreased in the VLDL and triglyceride levels was seen in 5b and 5f treated groups compared to insulin resistant (IR) group. It improved glycogenesis by catabolism of glucose and maintained glycaemic control. Similarly it had marked action on enzymatic oxidative biomarkers. Compound 5b displayed better, improved T1/2 (half-life) of 4.21 h and Kel (elimination constant) of 0.381 was noticed in comparison to compound 5f indicating the pharmacokinetic profile. Insilico studies like DFT calculations refined the geometry of 5b and 5f ligands, docking and molecular simulation provided the insights in binding affinity, dynamic behaviour and stability of ligands in PPAR-γ ligand binding domain. MM/GBSA provided the energetics of 5b and 5f in binding pocket. Finally network pharmacology identified ADIPOQ (adiponectin), NR1C3 (PPAR-γ), SLC2A4 (GLUT4), and LEP (leptin) proteins associate with compound 5b and 5f and enriched in Adipocytokine pathway, and PPAR-γ signaling pathway.

Rifaximin alleviates MCD diet-induced NASH in mice by restoring the gut microbiota and intestinal barrier

AimsDue to the increasing global incidence rate of nonalcoholic steatohepatitis (NASH) combined with the lack of effective treatment methods for this disease, there is an urgent need to find new treatment strategies. The aim of this study was to investigate the efficacy of rifaximin in preventing and treating NASH and the related mechanism. Materials and methodsA NASH model was constructed by feeding male C57BL/6 mice a methionine-choline-deficient (MCD) diet for 4 weeks. Rifaximin was administered for 1 week before MCD diet feeding or during the last week of MCD diet feeding to investigate its preventive or therapeutic effects. Liver pathology, hepatic enzyme levels and metabolic indices were measured to evaluate the effects of rifaximin on NASH. Intestinal barrier integrity was measured via the Ussing chamber system and western blotting. 16S rDNA sequencing was conducted to investigate the fecal microbiota composition. Western blotting was performed to evaluate peroxisome proliferator activated receptor (PPAR)α and PPARγ protein levels. Key findingsRifaximin effectively alleviated MCD diet-induced NASH. The microbiota composition in MCD diet-fed mice was significantly altered, and intestinal barrier integrity was disrupted. Dysbiosis and intestinal barrier dysfunction were reversed by rifaximin. In addition, rifaximin modulated PPARα and PPARγ expression in the liver. SignificanceRifaximin effectively alleviated MCD diet-induced NASH by restoring the gut microbiota and reversing intestinal barrier dysfunction, suggesting that rifaximin treatment is a new approach for preventing and treating NASH.

Cystathionine-γ-lyase contributes to tamoxifen resistance, and the compound I194496 alleviates this effect by inhibiting the PPARγ/ACSL1/STAT3 signalling pathway in oestrogen receptor-positive breast cancer

Tamoxifen (TAM) resistance is a major challenge in treating oestrogen receptor-positive (ER+) breast cancers. It is possible that the H2S synthase cystathionine-γ-lyase (CSE), which has been previously shown to promote tumour growth and metastasis in other cancer cells, is involved in this resistance. Therefore, we investigated CSE's role and potential mechanisms in TAM-resistant breast cancer cells. First, we examined the effect of CSE expression on TAM sensitivity and resistance in MCF7 (breast cancer) cells. The findings revealed that CSE was directly associated with TAM sensitivity and involved in TAM resistance in ER+ breast cancer cells, indicating that it may be useful as a biomarker. Next, we wanted to determine the molecular mechanism of CSE's role in TAM resistance. Using cell migration, co-immunoprecipitation, western blotting, and cell viability assays, we determined that the CSE/H2S system can affect the expression of PPARγ by promoting the sulfhydrylation of PPARγ, which regulates the transcriptional activity of ACSL1. ACSL1, in turn, influences STAT3 activation by affecting the phosphorylation, palmitoylation and dimerization of STAT3, ultimately leading to the development of TAM resistance in breast cancer. Finally, we examined the effect of CSE inhibitors on reducing drug resistance to determine whether CSE may be used as a biomarker of TAM resistance. We observed that the novel CSE inhibitor I194496 can reverse TAM resistance in TAM-resistant breast cancer via targeting the PPARγ/ACSL1/STAT3 signalling pathway. Overall, our data indicate that CSE may serve as a biomarker of TAM resistance and that the CSE inhibitor I194496 is a promising candidate for combating TAM resistance.

MicroRNA-34a and promoter methylation contribute to peroxisome proliferator-activated receptor gamma gene expression in patients with type 2 diabetes

AimsThis study aimed to investigate the roles of DNA methylation and miR-34a in the regulation of peroxisome proliferator-activated receptor gamma (PPARγ) in patients with type 2 diabetes (T2D). MethodsWe investigated the methylation status of four regions of the PPARγ promoter and PPARγ expression in a panel of 84 T2D patients using methylation-specific PCR (MSP) and RT-qPCR, respectively. Moreover, we quantified DNA methyltransferases (DNMTs) expression and global DNA methylation levels by RT-qPCR and ELISA, respectively. We measured the expression levels of miR-34a and protein expression of PPARγ by stem-loop RT-qPCR and ELISA, respectively. ResultsWe found significant DNA hypermethylation in the R2 and R3 regions of the PPARγ promoter in people with diabetes. Functionally, this was associated with a significant reduction in PPARγ expression. In addition, we observed a significant increase in 5-methylcytosine levels in people with diabetes. A marked increase in circulating miR-34a in the early stages of T2D (up to 10 years) and a significant decrease in circulating miR-34a with increasing diabetes duration from 10 years after the onset of diabetes. Interestingly, upregulation of DNA methyltransferases 1 (DNMT1), DNMT3A, and DNMT3B was observed in people with diabetes, and the average expression of DNMTs was negatively correlated with circulating miR-34a levels. In contrast, the serum protein level of PPARγ, a direct target of miR-34a, increased considerably with diabetes duration and showed a negative correlation with circulating miR-34a, cholesterol, triglyceride, and low-density lipoprotein. ConclusionPPARγ promoter hypermethylation and miR-34a upregulation are associated with T2D pathogenesis through PPARγ dysregulation.

Integrative microbiomics, proteomics and lipidomics studies unraveled the preventive mechanism of Shouhui Tongbian Capsules on cerebral ischemic stroke injury

Ethnopharmacological relevanceCerebral ischemic stroke (CIS) is one of the most important factors leading to death and disability, which seriously threaten the survival and health of patients. The intentional flora and its derived metabolites are demonstrated to play vital roles in the physiology and onset of CIS. Shouhui Tongbian Capsules (SHTB), a Traditional Chinese Medicine, could regulate gut microbiota and metabolites. Study has found that SHTB has protective effect on CIS, but the mechanism is still unclear. Aim of studyThis study was designed to evaluate the preventive effects and the mechanism of SHTB on CIS injury. Materials and methodsThe rats were pretreated with SHTB for 5 days, then the middle cerebral artery occlusion/reperfusion (MCAO/R) was established. Neurological deficit score, TTC staining, brain water content, H&E and Nissl staining were preformed to evaluate the preventive effects of SHTB on CIS. The Occludin and ZO-1 were analyzed to evaluate the blood-brain barrier (BBB). 16S rDNA sequencing and LC-ESI-MS/MS-based metabolomics profiling were performed to analyze the gut microbiota composition and short chain fatty acids (SCFAs) profile in gut. Serum lipopolysaccharide specific IgA antibody (LPS-SIgA) and diamine oxidase (DAO), as well as colon Claudin 5 and ZO-1 were analyzed to evaluate the intestinal barrier. Proteomics was used to evaluated the proteins profile in brain. Lipidomics were used to evaluate the brain SCFAs as well as medium and long chain fatty acids (MCFAs and LCFAs). Malondialdehyde (MDA), Total Superoxide dismutase (T-SOD), Glutathione (GSH), Glutathione peroxidase (GSH-Px), Catalase (CAT) and reactive oxygen species (ROS) were assayed to evaluate the oxidative stress in brain. Western blot was performed to evaluate the expression of PPARγ, Nrf2, SLC3A2, SCL7A11, GPX4, ACSL4 and LOX. ResultsSHTB prevented rats from MCAO/R injury, which was confirmed by lower cerebral infarct rate, brain water content, neurological deficit score and nissl body loss, and improved brain pathology. Meanwhile, SHTB upregulated the expression of ZO-1 and Occludin to maintain the integrity of BBB. 16S rDNA sequencing and LC-ESI-MS/MS-based targeted metabolomics found that SHTB increased the abundance of gut microbiota, regulated the numbers of intestinal bacteria to increase the production of Acetic acid, Propionic acid, and Butyric acid, as well as decrease the production of Valeric acid and Hexanoic acid in the gut. Meanwhile, SHTB improved the intestinal barrier by upregulating the protein levels of Claudin 5 and ZO-1, which was confirmed by low concentrations of LPS-SIgA and DAO in serum. Multi omics and spearman correlation analysis indicated that SHTB regulated the abundance of Escherichia-Shigella and Lactobacillus to increase Acetic acid, Propionic acid, and Butyric acid to induce the expression of PPARγ, thereby regulating fatty acid metabolism and degradation, improving lipid metabolism disorders, downregulating lipid oxidative stress, inhibiting ferroptosis, and alleviating brain injury. ConclusionThis study confirmed that SHTB improved the disturbance of fatty acid metabolism in brain tissue by regulating gut microbiota and the production of fecal SCFAs to inhibit ferroptosis caused by lipid oxidative stress and prevent CIS injury, which provided a potential candidate drug for the prevention of CIS.

SUN1 inhibits osteogenesis and promotes adipogenesis of human adipose-derived stem cells by regulating α-tubulin and CD36 expression.

Sad and UNC84 domain 1 (SUN1) is a kind of nuclear envelope protein with established involvement in cellular processes, including nuclear motility and meiosis. SUN1 plays an intriguing role in human adipose-derived stem cells (hASCs) differentiation; however, this role remains largely undefined. This study was undertaken to investigate the role of SUN1 in hASCs differentiation, as well as its underlying mechanisms. Employing siRNAs, we selectively downregulated SUN1 and CD36 expression. Microtubules were depolymerized using nocodazole, and PPARγ was activated using rosiglitazone. Western blotting was performed to quantify SUN1, PPARγ, α-tubulin, CD36, OPN, and adiponectin protein expression levels. Alkaline phosphatase and Oil red O staining were used to assess osteogenesis and adipogenesis, respectively. Downregulated SUN1 expression increased osteogenesis and decreased adipogenesis in hASCs, concomitant with upregulated α-tubulin expression and downregulated CD36 expression, alongside reduced nuclear localization of PPARγ. Microtubule depolymerization increased CD36 expression. Rescue experiments indicated that microtubule depolymerization counteracted the downregulated SUN1-induced phenotypic changes. This study demonstrates that SUN1 influences the differentiation of hASCs towards osteogenic and adipogenic lineages, indicating its essential role in cell fate.

PPARγ/ETV2 axis regulates endothelial-to-mesenchymal transition in pulmonary hypertension.

Endothelial-to-mesenchymal transition (EndoMT) plays an important role in pulmonary hypertension (PH) but the molecular mechanisms regulating EndoMT remain to be defined. We demonstrate that the axis of the transcription factors PPARγ (Peroxisome Proliferator-Activated Receptor gamma) and ETV2 (ETS variant 2) play important roles in the pathogenesis of PH. Decreased levels of the expression of PPARγ and ETV2 along with reduced endothelial and increased EndoMT markers are consistently observed in lungs and pulmonary artery endothelial cells (PAECs) of idiopathic pulmonary arterial hypertension patients, in hypoxia-exposed mouse lungs, human PAECs, and in induced-EndoMT cells. Etv2 +/- mice spontaneously developed PH and right ventricular hypertrophy (RVH), associated with increased EndoMT markers and decreased EC markers. Interestingly, chronic hypoxia exacerbated right ventricular systolic pressure and RVH in Etv2 +/- mice. PPARγ transcriptionally activates the ETV2 promoter. Consistently, while mice overexpressing endothelial PPARγ increases the expression of ETV2 and endothelial markers with reduced EndoMT markers, endothelial PPARγ KO mice show decreased ETV2 expression and enhanced EndoMT markers. Inducible overexpression of ETV2 under induced-EndoMT cell model reduces number of cells with mesenchymal morphology and decreases expression of mesenchymal markers with increased EC makers, compared to control. Therefore, our study suggests that PPARγ-ETV2 signaling regulates PH pathogenesis through EndoMT.

Effect of Siegesbeckia glabrescens Extract on Foam Cell Formation in THP-1 Macrophages.

The accumulation of cholesterol-bearing macrophage foam cells in the initial stages of atherosclerosis serves as a characteristic feature of atherosclerotic lesions. The inhibitory effect of Siegesbeckia glabrescens, a species of flowering plant in the Asteraceae family, on foam cell formation in THP-1 macrophages has not yet been elucidated. In this study, we explored the effect of S. glabrescens ethanol extract (SGEE) and hot water extract (SGWE) on foam cell formation via co-treatment with oxidized low density lipoprotein (ox-LDL) and lipopolysaccharide (LPS), mimicking the occurrence of atherosclerosis in vitro, and studied the regulation of its underlying mechanisms. THP-1 cells differentiated by PMA (1 μM) for 48 h were subsequently treated with/without SGWE and SGEE for 48 h. THP-1 macrophages were treated with ox-LDL (20 μg/mL) and LPS (500 ng/mL) for 24 h. Treatment with ox-LDL and LPS for 24 h enhanced the lipid accumulation in foam cells compared to in untreated cells, as determined by oil red O staining. In contrast, SGWE and SGEE treatment inhibited lipid accumulation in foam cells. Both extracts significantly upregulated ABCA1, LXRα, and PPARγ expression in ox-LDL- and LPS-treated cells (P<0.05). Moreover, both SGWE and SGEE decreased LOX-1, CD36, and SR-A1 expression. The co-treatment of ox-LDL and LPS increased NF-κB, COX-2, and pro-inflammatory activation and expression compared with untreated cells. However, this increase suppressed NF-κB, COX-2, and pro-inflammatory expression by SGWE and SGEE. The results indicated that both extracts can partially inhibit foam cell formation and contribute to protective effects by suppressing cholesterol accumulation during the onset of atherosclerosis.

Sodium Hypochlorite (NaClO) Disturbed Lipid Metabolism in Larval Zebrafish (Danio rerio), as Revealed by Lipidomics and Transcriptomics Analyses.

Sodium hypochlorite (NaClO) has been widely utilized since the initial outbreak of coronavirus disease (COVID-19). The widespread use of NaClO means that it can directly enter aquatic ecosystems through wastewater discharge. In this study, we analyzed the expression of PPAR-γ, FAS, and ACC1, which significantly increased in larval zebrafish following exposure to 300 μg/L NaClO for 7 days. Additionally, we examined the effects of high concentrations of NaClO on zebrafish through non-targeted lipidomics and transcriptomics. A total of 44 characteristic lipid molecules were identified using non-targeted lipidomics; an absolute quantitative analysis revealed that the contents of these subclasses of lipids decreased significantly following exposure to 300 μg/L NaClO for 7 days. The levels of triglyceride (TG), phosphatidylethanolamines (PE), and diglyceride (DG) were particularly affected. Transcriptomic analysis revealed that exposure to 300 μg/L NaClO could significantly disrupt global gene transcription in larval zebrafish. Interestingly, more than 700 differentially expressed genes (DEGs) were identified, primarily associated with lipid metabolism and glycometabolism pathways. Overall, our study provided new insights into the toxicological effects of chlorine-containing disinfectants in aquatic organisms.

New stilbenes from Cajanus cajan inhibit adipogenesis in 3T3-L1 adipocytes through down-regulation of PPARγ

Two new stilbenes, denominated Cajanotone B (CAB) and Cajanotone C (CAC), were isolated from the leaves of Cajanus cajan. In this study, the structures of CAB and CAC were unambiguously elucidated by a combination of various spectral methods. Both compounds significantly inhibited the adipogenesis in 3T3-L1 adipocytes by reducing the lipid accumulation, triglyceride content and FFA secretion. CAB and CAC also substantially inhibit the mRNA expression of HSL, ATGL, C/EBPα and PPARγ as deciphered based by RT-PCR assay. Down-regulation of PPAR is believed to be the primary mechanism underlying which CAB and CAC inhibited adipogenic differentiation because the lipid-promoting activity of PPAR agonists can be counteracted by these compounds. The molecular interaction between CAB/CAC and PPARγ was revealed with the help of molecular docking. Taken together, CAB and CAC could serve as new lead compounds with the potential to speed up the development of novel lipid-lowering and weight-control therapies.

Ultra-high pressure assisted extraction of polysaccharide from Bangia fusco-purpurea: Structure and in vitro hypolipidemic activity

The structure and in vitro hypolipidemic activity of Bangia fusco-purpurea polysaccharide (BFP) assisted extracted with ultra-high pressure (UHP) at 100–600 MPa were studied. Compared to native BFP, UHP assisted extracted BFP had a more loose network structure with higher total sugar and uronic acid contents while less molecular weight (p < 0.05). Moreover, UHP assisted extraction significantly improved the in vitro hypolipidemic and antioxidant activity of BFP. Especially at 400 MPa UHP, the cholesterol adsorption and antioxidant capacities of BFP were increased by approximately 38.02 % and 11.69 %–32.29 %, respectively. BFP with UHP assisted extraction could alleviate oleic acid-induced lipid accumulation and lipid oxidation in HepG2 cells more effectively by activating the AMPK signaling pathway as well as inhibiting PPARγ expression, which was much related with its reduced molecular weight and loose network structure. The findings indicated that UHP assisted extracted BFP has better potential to develop natural hypolipidemic agent.

Effects of chronic intermittent hypoxia and reoxygenation on insulin resistance and skeletal muscle miR-27a-3p/PPARγ/IRS1/PI3K/AKT expressions in rats

To investigate the effects of chronic intermittent hypoxia (CIH) and reoxygenation on insulin resistance (IR) and expressions of miR-27a-3p/PPARγ/IRS1/PI3K/AKT in rat skeletal muscle. GEO database was used for screening the differentially expressed miRNAs in CIH, and their target genes were subjected to GO and KEGG enrichment analysis followed by construction of the miRNA-mRNA-pathway regulatory network using Cytoscape. In the animal experiment, 48 male SD rats were randomly divided into normoxia group and CIH group (8 weeks of CIH followed by 4 weeks of normoxic recovery). Blood and skeletal muscle samples were collected at baseline, 8 weeks, and 12 weeks to evaluate the changes in fasting blood glucose (FBG) and fasting insulin (FINS) levels and muscular pathology. RT-qPCR and Western blotting were used to detect the changes in the expressions of miR-27a-3p, PPARγ, GLUT4, IRS1, p-IRS1, PI3K, p-AKT and AKT in the muscular tissues. No muscular miRNA datasets for CIH were available in GEO database, from which only a kidney-related dataset (GSE202480) was obtained, based on which a total of 165 differentially expressed miRNAs were identified. GO/KEGG analysis suggested that these miRNAs were involved in muscular regulation and insulin signaling. The miRNA-mRNA-pathway network highlighted miR-27a-3p as a crucial regulator in the PPAR and PI3K/AKT pathway. In the animal experiment, the rats subjected to CIH for 8 weeks showed significantly increased FBG, FINS, HOMA-IR, and PPARγ levels, loose muscle fiber arrangement, decreased cross-sectional area of the muscle fibers, and lowered expressions of miR-27a-3p, p-IRS1/IRS1, PI3K, and p-AKT/AKT in the skeletal muscles. CIH increases IR, causes skeletal muscle pathology, downregulates miR-27a-3p expression, upregulates PPARγ expression, and inhibits IRS1/PI3K/AKT insulin signaling in the skeletal muscles of rats, and these changes can be reversed by reoxygenation. MiR-27a-3p may participate in CIH-induced IR by modulating the PPAR γ/IRS1/PI3K/AKT signaling pathway.

Knock-out of CD73 delays the onset of HR-negative breast cancer by reprogramming lipid metabolism and is associated with increased tumor mutational burden

ObjectiveCD73 (ecto-5′-nucleotidase, NT5E), a cell-surface enzyme converting 5′-AMP to adenosine, is crucial for cancer progression. However, its role in the tumorigenesis process remains mostly obscure. We aimed to demonstrate CD73's role in breast cancer (BC) tumorigenesis through metabolic rewiring of fatty acid metabolism, a process recently indicated to be regulated by BC major prognostic markers, hormone receptors (HR) for estrogen (ER), and progesterone (PR). MethodsA murine model of chemically induced mammary gland tumorigenesis was applied to analyze CD73 knock-out (KO)-induced changes at the transcriptome (RNA-seq), proteome (IHC, WB), and lipidome (GC-EI-MS) levels. CD73 KO-induced changes were correlated with scRNA-seq and bulk RNA-seq data for human breast tissues and BCs from public collections and confirmed at the proteome level with IHC or WB analysis of BC tissue microarrays and cell lines. ResultsCD73 KO delayed the onset of HR/PR-negative mammary tumors in a murine model. This delay correlated with increased expression of genes related to biosynthesis and β-oxidation of fatty acids (FAs) in the CD73 KO group at the initiation stage. STRING analysis based on RNA-seq data indicated an interplay between CD73 KO, up-regulated expression of PR-coding gene, and DEGs involved in FA metabolism, with PPARγ, a main regulator of FA synthesis, as a main connective node. In epithelial cells of mammary glands, PPARγ expression correlated with CD73 at the RNA level. With cancer progression, CD73 KO increased the levels of PUFAn3/6 (polyunsaturated omega 3/6 FAs), known ligands of PPARγ and target for lipid peroxidation, which may lead to oxidative DNA damage. It correlated with the downregulation of genes involved in cellular stress response (Mlh1, Gsta3), PR–or CD73-dependent changes in the intracellular ROS levels and expression or activation of proteins involved in DNA repair or oxidative stress response in mammary tumor or human BC cell lines, increased tumor mutational burden (TMB) and genomic instability markers in CD73 low HR-negative human BCs, and the prolonged onset of tumors in the CD73 KO HR/PR-negative group. ConclusionsCD73 has a significant role in tumorigenesis driving the reprogramming of lipid metabolism through the regulatory loop with PR and PPARγ in epithelial cells of mammary glands. Low CD73 expression/CD73 KO might enhance mutational burden by disrupting this regulatory loop, delaying the onset of HR-negative tumors. Our results support combining therapy targeting the CD73-adenosine axis and tumor lipidome against HR-negative tumors, especially at their earliest developmental stage.

Erythropoietin regulates osteoclast formation via up-regulating PPARγ expression

Erythropoietin (EPO), expressed in red blood progenitor cells, primarily regulates erythropoiesis by binding to its receptor. Besides anemia, recent studies have identified new therapeutic indications for EPO that are not connected to red blood cell formation. Elevated EPO levels harm bone homeostasis in adult organisms and are associated with increased osteoclast; however, the underlying molecular mechanisms remain unclear. This study demonstrated that EPO enhanced osteoclast differentiation and bone resorption in vitro. We showed that EPO promoted osteoclast formation by up-regulating PPARγ expression through activating the Jak2/ERK signaling pathway. Consistently, PPARγ antagonists rescued the hyperactivation of osteoclasts due to EPO, while PPARγ agonists reversed the EMP9-mediated decrease in osteoclast differentiation. Further, exposing female mice to EPO for two months led to a decrease in bone mass and increased osteoclast numbers. The present results suggested that EPO promotes osteoclastogenesis by regulating the Jak2/ERK/ PPARγ signaling pathway. From a clinical perspective, the risk of compromised bone health should be considered when using EPO to treat anemia in post-operative patients with intertrochanteric fractures of the femur, as it could significantly impact the patient’s recovery and quality of life.

Yanghe Decoction promotes ferroptosis through PPARγ-dependent autophagy to inhibit the malignant progression of triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a heterogeneous subtype of breast cancer that displays highly aggressive with poor prognosis. Yanghe Decoction (YHD) has been used in the treatment of breast cancer for many years. We aimed to explore the effects of YHD on the malignant phenotypes of MDA-MB-231 cells and the potential mechanism related to PPARγ, autophagy and ferroptosis. The serum of rat containing different concentrations of YHD were collected to culture MDA-MB-231 cells. Cell viability and proliferation were assessed by the CCK-8 assay and EDU staining. Wound healing- and transwell assays were used to detect the capacities of MDA-MB-231 cell migration and invasion. Additionally, the levels of lipid peroxidation, Fe2+ and the expression of ferroptosis-related proteins were evaluated. The expression of PPARγ and autophagy-related proteins was assessed using immunofluorescence staining or western blot assay. Then, the PPARγ inhibitor (GW9662), autophagy inhibitor (3-MA) and autophagy inducer (rapamycin; Rap) were used to further study the potential mechanism of YHD on TNBC. Results indicated that contained-YHD serum significantly decreased the viability, proliferation, migration and invasion of TNBC cells. Moreover, YHD promoted lipid peroxidation level, elevated Fe2+ content and downregulated GPX4, SLC7A11 and SLC3A2 expression. Besides, autophagy was induced and PPARγ was upregulated by YHD in MDA-MB-231 cells. Furthermore, GW9662 alleviated the impacts of YHD on autophagy of MDA-MB-231 cells. Rap reversed the effects of GW9662 on lipid peroxidation, ferroptosis, proliferation, migration and invasion of MDA-MB-231 cells. 3-MA had the similar effects to GW9662. Collectively, YHD suppressed the malignant progression of MDA-MB-231 cells by inducing ferroptosis through PPARγ-dependent autophagy.

Empagliflozin Attenuates Pulmonary Arterial Remodeling Through Peroxisome Proliferator-Activated Receptor Gamma Activation.

The loss of peroxisome proliferator-activated receptor gamma (PPARγ) exacerbates pulmonary arterial hypertension (PAH), while its upregulation reduces cell proliferation and vascular remodeling, thereby decreasing PAH severity. SGLT2 inhibitors, developed for type 2 diabetes, might also affect signal transduction in addition to modulating sodium-glucose cotransporters. Pulmonary arterial smooth muscle cells (PASMCs) isolated from patients with idiopathic pulmonary arterial hypertension (IPAH) were treated with three SGLT2 inhibitors, canagliflozin (Cana), dapagliflozin (Dapa), and empagliflozin (Empa), to investigate their antiproliferative effects. To assess the impact of Empa on PPARγ, luciferase reporter assays and siRNA-mediated PPARγ knockdown were employed to examine regulation of the γ-secretase complex and its downstream target Notch3. Therapy involving daily administration of Empa was initiated 21 days after inducing hypoxia-induced PAH in mice. Empa exhibited significant antiproliferative effects on fast-growing IPAH PASMCs. Empa activated PPARγ to prevent formation of the γ-secretase complex, with specific impacts on presenilin enhancer 2 (PEN2), which plays a crucial role in maintaining γ-secretase complex stability, thereby inhibiting Notch3. Similar results were obtained in lung tissue of chronically hypoxic mice. Empa attenuated pulmonary arterial remodeling and right ventricle hypertrophy in a hypoxic PAH mouse model. Moreover, PPARγ expression was significantly decreased and PEN2, and Notch3 levels were increased in lung tissue from PAH patients compared with non-PAH lung tissue. Empa reverses vascular remodeling by activating PPARγ to suppress the γ-secretase-Notch3 axis. We propose Empa as a PPARγ activator and potential therapeutic for PAH.

298 Botanicals reduce osteoarthritic-like inflammation influencing the endocannabinoid system in vitro

Abstract Osteoarthritis (OA) is a prevalent joint disease in dogs. Botanicals (BOT) interacting with the endocannabinoid system (ECS) can reduce pain, inflammation, and other OA-related processes, and could become potential treatments for pets. This study investigates various BOT in vitro for their potential to reduce OA-like inflammation, oxidative stress, and apoptosis, and influence the expression of ECS enzymes or receptors. Capsicum oleoresin (10% capsaicinoids) at 100 ppm, cinnamaldehyde at 5 ppm, turmeric extract (95% curcuminoids) at 10 ppm, and eugenol at 10 ppm were selected for their documented ability to interact with the ECS and used as treatments. The efficacy of these BOT was assessed by pre-treating human chondrosarcoma cells (SW1353 - ATCC HTB-94) with BOT for 2 h before exposure to interleukin (IL)1β and tumor necrosis factor (TNF) α for 24 h. Following the challenge, the cells and supernatants were collected. Then, qPCR on selected markers and IL8 quantification with ELISA were conducted. Additionally, to assess antioxidant and anti-apoptotic capabilities, BOT-treated cells were exposed to menadione for 1 h to measure reactive oxygen species (ROS) and for 6 h to induce apoptosis and evaluate chondrocyte viability. Data were analyzed using one-way ANOVA with Tukey’s multiple comparisons (n = 3; P &amp;lt; 0.05) and reported in this work compared against the positive control. Under inflammatory conditions, SW1353 cells exhibited a significant increase in IL6 (234-fold; P = 0.0333) and IL8 (4,500-fold; P = 0.0395) expression, and MMP1 (13-fold, P = 0.0052), MMP3 (40-fold; P = 0.0474), and MMP13 (26-fold; P = 0.0260) expression. Among the different BOTs, only cinnamaldehyde effectively countered IL6 and IL8 upregulation, reducing their expression to 0 for IL6 and by 4,400-fold for IL8 (P = 0.0086). Additionally, it reduced MMP3 by 40-fold (P = 0.0242) and MMP13 by 24-fold (P = 0.0275), while eugenol significantly reduced MMP3 by 36-fold (P = 0.0250). Only cinnamaldehyde significantly decreased IL8 secretion by 86% (P &amp;lt; 0.0001), and all tested botanicals reduced chondrocyte apoptosis (P &amp;lt; 0.0001). Eugenol and turmeric extract exhibited significant antioxidant effects, reducing ROS levels by 70% compared with the positive control (P &amp;lt; 0.05). Concerning ECS response to the inflammatory challenge, MAGL levels increased by 4.2-fold (P = 0.0253), with cinnamaldehyde significantly reducing its mRNA expression by 4-fold (P = 0.0078). PPAR-γ expression showed a numerical decrease of 0.7-fold under inflammatory conditions, but cinnamaldehyde and capsicum oleoresin upregulated its mRNA expression by 2.3-fold (P = 0.0162) and 1.3-fold (P = 0.0006), respectively. Cinnamaldehyde also reduced DAGLα expression by 0.3-fold (P = 0.0079), and upregulated CBR2 and NRF2 mRNA expression by 7-fold (P &amp;lt; 0.0001) and 1.6-fold (P = 0.0295) respectively, while other botanicals had no effects. In conclusion, the tested BOTs displayed promising properties to mitigate OA in vitro, with cinnamaldehyde proving to be the most promising one. These findings suggest the potential of BOT active on ECS as a novel treatment for canine OA, prompting further in vivo research for comprehensive characterization.