PPAR-α inhibits DHEA-induced ferroptosis in granulosa cells through upregulation of FADS2.

BACKGROUND: Polycystic ovary syndrome (PCOS), a prevalent endocrine disorder among women of reproductive age, is characterized by disturbances in hormone levels and ovarian dysfunction. Ferroptosis, a unique form of regulated cell death characterized by iron-dependent lipid peroxidation. Emerging evidence indicates that ferroptosis may have a significant role in the pathogenesis of PCOS, highlighting the importance of studying this mechanism to better understand the disorder and potentially develop novel therapeutic interventions. METHODS: To create an in vivo PCOS model, mice were injected with dehydroepiandrosterone (DHEA) and the success of the model was confirmed through further assessments. Ferroptosis levels were evaluated through detecting ferroptosis-related indicators. Ferroptosis-related genes were found through bioinformatic analysis and identified by experiments. An in vitro PCOS model was also established using DHEA treated KGN cells. The molecular binding relationship was confirmed using a chromatin immunoprecipitation (ChIP) assay. RESULTS: In PCOS model, various ferroptosis-related indicators such as MDA, Fe2+, and lipid ROS showed an increase, while GSH, GPX4, and TFR1 exhibited a decrease. These findings indicate an elevated level of ferroptosis in the PCOS model. The ferroptosis-related gene FADS2 was identified and validated. FADS2 and PPAR-α were shown to be highly expressed in ovarian tissue and primary granulosa cells (GCs) of PCOS mice. Furthermore, the overexpression of both FADS2 and PPAR-α in KGN cells effectively suppressed the DHEA-induced increase in ferroptosis-related indicators (MDA, Fe2+, and lipid ROS) and the decrease in GSH, GPX4, and TFR1 levels. The ferroptosis agonist erastin reversed the suppressive effect, suggesting the involvement of ferroptosis in this process. Additionally, the FADS2 inhibitor SC26196 was found to inhibit the effect of PPAR-α on ferroptosis. Moreover, the binding of PPAR-α to the FADS2 promoter region was predicted and confirmed. This indicates the regulatory relationship between PPAR-α and FADS2 in the context of ferroptosis. CONCLUSIONS: Our study indicates that PPAR-α may have an inhibitory effect on DHEA-induced ferroptosis in GCs by enhancing the expression of FADS2. This discovery provides valuable insights into the pathophysiology and potential therapeutic targets for PCOS.

MicroRNA-144-3p Inhibits Host Lipid Catabolism and Autophagy by Targeting PPARα and ABCA1 During Mycobacterium Tuberculosis Infection.

MicroRNA-mediated metabolic reprogramming recently has been identified as an important strategy for Mycobacterium tuberculosis (Mtb) to evade host immune responses. However, it is unknown what role microRNA-144-3p (miR-144-3p) plays in cellular metabolism during Mtb infection. Here, we report the meaning of miR-144-3p-mediated lipid accumulation for Mtb-macrophage interplay. Mtb infection was shown to upregulate the expression of miR-144-3p in macrophages. By targeting peroxisome proliferator-activated receptor α (PPARα) and ATP-binding cassette transporter A1 (ABCA1), miR-144-3p overexpression promoted lipid accumulation and bacterial survival in Mtb-infected macrophages, while miR-144-3p inhibition had the opposite effect. Furthermore, reprogramming of host lipid metabolism by miR-144-3p suppressed autophagy in response to Mtb infection. Our findings uncover that miR-144-3p regulates host metabolism and immune responses to Mtb by targeting PPARα and ABCA1, suggesting a potential host-directed tuberculosis therapy by targeting the interface of miRNA and lipid metabolism.

[Gualou Xiebai Banxia Decoction treats type 2 diabetes mellitus combined with acute myocardial infarction via chemerin/ CMKLR1/PPARα signaling pathway].

This study aims to investigate the effects of Gualou Xiebai Banxia Decoction(GXBD) on type 2 diabetes mellitus(T2DM) combined with acute myocardial infarction(AMI) in rats via chemerin/chemokine-like receptor 1(CMKLR1)/peroxisome proliferator-activated receptor α(PPARα) signaling pathway, and to explore the mechanism of GXBD in alleviating glucose and lipid metabolism disorders. The SD rats were randomized into control, model, positive control, and low-and high-dose GXBD groups. The rat model of T2DM was established by administration with high-fat emulsion(HFE) by gavage and intraperitoneal injection with streptozotocin, and then coronary artery ligation was performed to induce AMI. The control and model groups were administrated with the equal volume of normal saline, and other groups were administrated with corresponding drugs by gavage. Changes in relevant metabolic indicators were assessed by ELISA and biochemical assays, and the protein levels of chemerin, CMKLR1, and PPARα in the liver, abdominal fat, and heart were determined by Western blot. The results showed that GXBD alleviated the myocardial damage and reduced the levels of blood lipids, myocardial enzymes, and inflammatory cytokines, while it did not lead to significant changes in blood glucose. Compared with the model group, GXBD down-regulated the expression of chemerin in peripheral blood and up-regulated the expression of cyclic adenosine monophosphate(cAMP) and protein kinase A(PKA) in the liver. After treatment with GXBD, the protein levels of chemerin and CMKLR1 in the liver, abdominal fat, and heart were down-regulated, while the protein levels of PPARα in the liver and abdominal fat were up-regulated. In conclusion, GXBD significantly ameliorated the disorders of glycolipid metabolism in the T2DM-AMI model by regulating the chemerin/CMKLR1/PPARα signaling pathway to exert a protective effect on the damaged myocardium. This study provides a theoretical basis for further clinical study of GXBD against T2DM-AMI and is a manifestation of TCM treatment of phlegm and turbidity causing obstruction at the protein level.

Loss of lncRNA LINC01056 leads to sorafenib resistance in HCC.

BACKGROUND AND AIMS: Sorafenib is a major nonsurgical option for patients with advanced hepatocellular carcinoma (HCC); however, its clinical efficacy is largely undermined by the acquisition of resistance. The aim of this study was to identify the key lncRNA involved in the regulation of the sorafenib response in HCC. MATERIALS AND METHODS: A clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) single-guide RNA (sgRNA) synergistic activation mediator (SAM)-pooled lncRNA library was applied to screen for the key lncRNA regulated by sorafenib treatment. The role of the identified lncRNA in mediating the sorafenib response in HCC was examined in vitro and in vivo. The underlying mechanism was delineated by proteomic analysis. The clinical significance of the expression of the identified lncRNA was evaluated by multiplex immunostaining on a human HCC microtissue array. RESULTS: CRISPR/Cas9 lncRNA library screening revealed that Linc01056 was among the most downregulated lncRNAs in sorafenib-resistant HCC cells. Knockdown of Linc01056 reduced the sensitivity of HCC cells to sorafenib, suppressing apoptosis in vitro and promoting tumour growth in mice in vivo. Proteomic analysis revealed that Linc01056 knockdown in sorafenib-treated HCC cells induced genes related to fatty acid oxidation (FAO) while repressing glycolysis-associated genes, leading to a metabolic switch favouring higher intracellular energy production. FAO inhibition in HCC cells with Linc01056 knockdown significantly restored sensitivity to sorafenib. Mechanistically, we determined that PPARα is the critical molecule governing the metabolic switch upon Linc01056 knockdown in HCC cells and indeed, PPARα inhibition restored the sorafenib response in HCC cells in vitro and HCC tumours in vivo. Clinically, Linc01056 expression predicted optimal overall and progression-free survival outcomes in HCC patients and predicted a better sorafenib response. Linc01056 expression indicated a low FAO level in HCC. CONCLUSION: Our study identified Linc01056 as a critical epigenetic regulator and potential therapeutic target in the regulation of the sorafenib response in HCC.

Hepatitis B virus X protein promotes tumor glycolysis by downregulating lncRNA OIP5-AS1/HKDC1 in HCC.

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related mortality worldwide, with Hepatitis B virus (HBV) infection being the leading cause. This study aims to investigate the role of HBV in HCC pathogenesis involving glucose metabolism. Long non-coding RNA (lncRNA) OIP5-AS1 was significantly downregulated in HBV-positive HCC patients, and its low expression indicated a poor prognosis. This lncRNA was primarily localized in the cytoplasm, acting as a tumor suppressor. HBV protein X (HBx) repressed OIP5-AS1 expression by inhibiting a ligand-activated transcriptional factor peroxisome proliferator-activated receptor α (PPARα). Furthermore, mechanistic studies revealed that OIP5-AS1 inhibited tumor growth by suppressing Hexokinase domain component 1 (HKDC1)-mediated glycolysis. The expression of HKDC1 could be enhanced by transcriptional factor sterol regulatory element-binding protein 1 (SREBP1). OIP5-AS1 facilitated the ubiquitination and degradation of SREBP1 to suppress HKDC1 transcription, which inhibited glycolysis. The results suggest that lncRNA OIP5-AS1 plays an anti-oncogenic role in HBV-positive HCC via the HBx/OIP5-AS1/HKDC1 axis, providing a promising diagnostic marker and therapeutic target for HBV-positive HCC patients.

Molecular Mechanisms of Fucoxanthin in Alleviating Lipid Deposition in Metabolic Associated Fatty Liver Disease.

Metabolic-associated fatty liver disease (MAFLD) is witnessing a global surge; however, it still lacks effective pharmacological interventions. Fucoxanthin, a natural bioactive metabolite derived from marine brown algae, exhibits promising pharmacological functions, particularly in ameliorating metabolic disorders. However, the mechanisms underlying its therapeutic efficacy in addressing MAFLD remain elusive. Our present findings indicated that fucoxanthin significantly alleviated palmitic acid (PA)-induced hepatic lipid deposition in vitro and obesity-induced hepatic steatosis in ob/ob mice. Moreover, at both the protein and transcriptional levels, fucoxanthin effectively increased the expression of PPARα and CPT1 (involved in fatty acid oxidation) and suppressed FASN and SREBP1c (associated with lipogenesis) in both PA-induced HepG2 cells and hepatic tissues in ob/ob mice. This modulation was accompanied by the activation of AMPK. The capacity of fucoxanthin to improve hepatic lipid deposition was significantly attenuated when utilizing the AMPK inhibitor or siRNA-mediated AMPK silencing. Mechanistically, fucoxanthin activates AMPK, subsequently regulating the KEAP1/Nrf2/ARE signaling pathway to exert antioxidative effects and stimulating the PGC1α/NRF1 axis to enhance mitochondrial biogenesis. These collective actions contribute to fucoxanthin's amelioration of hepatic steatosis induced by metabolic perturbations. These findings offer valuable insights into the prospective utilization of fucoxanthin as a therapeutic strategy for managing MAFLD.

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

Background: 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. Methods: 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). Results: 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. Conclusions: The current results confirmed that the three PPAR genes (PPARA, PPARD and PPARG) affected STAD development through mediating immune microenvironment and genome mutation.

Tyrosol regulates hepatic lipid metabolism in high-fat diet-induced NAFLD mice.

This study aimed to elucidate the effect of tyrosol (TYR) on the amelioration of nonalcoholic fatty liver disease (NAFLD). Male C57BL/6J mice were fed a low-fat diet (LFD), a high-fat diet (HFD), or a HFD supplemented with 0.025% (w/w) TYR (TYR) for 16 weeks. Following a 16-week intervention, the TYR cohort exhibited diminished final body weight and hepatic lipid accumulation, compared to HFD fed mice. Liver metabolomics analysis revealed that TYR increased the hepatic levels of spermidine, taurine, linoleic acid, malic acid and eicosapentaenoic acid (EPA), indicating the beneficial effect of TYR on lipid homeostasis. Using molecular docking analysis and the luciferase assay, we found that TYR acts as a ligand and binds with peroxisome proliferator-activated receptor-α (PPARα), which plays a pivotal role in the modulation of hepatic lipid metabolism, thereby activating the transcription of downstream genes. Our results suggest that TYR alleviates NAFLD in HFD-fed mice probably by the modulation of the PPARα signaling pathway.

Assessment of the mode of action of perchloroethylene-induced mouse liver tumors.

Perchloroethylene (PCE) is used as a solvent and chemical intermediate. Following chronic inhalation exposure, PCE selectively induced liver tumors in mice. Understanding the mode of action (MOA) for PCE carcinogenesis in mice is important in defining its possible human cancer risk. The proposed MOA is based on the extensive examination of the peer-reviewed studies that have assessed the mouse liver effects of PCE and its major oxidative metabolite trichloroacetic acid (TCA). Similar to PCE, TCA has also been demonstrated to liver tumors selectively in mice following chronic exposure. The Key Events (KE) of the proposed PCE MOA involve oxidative metabolism of PCE to TCA [KE 1]; activation of the peroxisome proliferator-activated receptor alpha (PPARα) [KE 2]; alteration in hepatic gene expression including cell growth pathways [KE 3]; increase in cell proliferation [KE 4]; selective clonal expansion of hepatic preneoplastic foci [KE 5]; and formation of hepatic neoplasms [KE 6]. The scientific evidence supporting the PPARα MOA for PCE is strong and satisfies the requirements for a MOA analysis. The PPARα liver tumor MOA in rodents has been demonstrated not to occur in humans; thus, human liver cancer risk to PCE is not likely.

SIRT6 activates PPARα to improve doxorubicin-induced myocardial cell aging and damage.

The Sirtuins family, formally known as the Silent Information Regulator Factors, constitutes a highly conserved group of histone deacetylases. Recent studies have illuminated SIRT6's role in doxorubicin (DOX)-induced oxidative stress and apoptosis within myocardial cells. Nevertheless, the extent of SIRT6's impact on DOX-triggered myocardial cell aging and damage remains uncertain, with the associated mechanisms yet to be fully understood. In our research, we examined the influence of SIRT6 on DOX-induced cardiomyocyte senescence using ß-galactosidase and γ-H2AX staining. Additionally, we gauged the mRNA expression of senescence-associated genes, namely p16, p21, and p53, through Real-time PCR. Employing ELISA assay kits, MDA, and total SOD activity assay kits, we measured inflammatory factors TNF-α, IL-6, and IL-1ß, alongside oxidative stress-related indicators. The results unequivocally indicated that SIRT6 overexpression robustly inhibited DOX-induced cardiomyocyte senescence. Furthermore, we established that SIRT6 overexpression suppressed the inflammatory response and oxidative stress induced by DOX in cardiomyocytes. Conversely, silencing SIRT6 exacerbated DOX-induced cardiomyocyte injury. Our investigations further unveiled that SIRT6 upregulated the expression of genes CD36, CPT1, LCAD, MCAD associated with fatty acid oxidation through its interaction with PPARα, thereby exerting anti-aging effects. In vivo, the overexpression of SIRT6 was observed to restore DOX-induced declines in EF and FS to normal levels in mice. Echocardiography and HE staining revealed the restoration of cardiomyocyte alignment, affording protection against DOX-induced myocardial senescence and injury. The findings from this study suggest that SIRT6 holds significant promise as a therapeutic target for mitigating DOX-induced cardiomyopathy.

Anti-steatotic effects of PPAR-alpha and gamma involve gut-liver axis modulation in high-fat diet-fed mice.

AIM: To evaluate the effects of PPARα and PPARγ activation (alone or in combination) on the gut-liver axis, emphasizing the integrity of the intestinal barrier and hepatic steatosis in mice fed a high saturated fat diet. METHODS: Male C57BL/6J were fed a control diet (C) or a high-fat diet (HF) for ten weeks. Then, a four-week treatment started: HF-α (WY14643), HF-γ (low-dose pioglitazone), and HF-αγ (combination). RESULTS: The HF caused overweight, insulin resistance, impaired gut-liver axis, and marked hepatic steatosis. Treatments reduced body mass, improved glucose homeostasis, and restored the gut microbiota diversity and intestinal barrier gene expression. Treatments also lowered the plasma lipopolysaccharide concentrations and favored beta-oxidation genes, reducing macrophage infiltration and steatosis in the liver. CONCLUSION: Treatment with PPAR agonists modulated the gut microbiota and rescued the integrity of the intestinal barrier, alleviating hepatic steatosis. These results show that these agonists can contribute to metabolic-associated fatty liver disease treatment.

Sodium butyrate alleviates free fatty acid-induced steatosis in primary chicken hepatocytes via the AMPK/PPARα pathway.

Fatty liver hemorrhagic syndrome (FLHS) is a prevalent metabolic disorder observed in egg-laying hens, characterized by fatty deposits and cellular steatosis in the liver. Our preliminary investigations have revealed a marked decrease in the concentration of butyric acid in the FLHS strain of laying hens. It has been established that sodium butyrate (NaB) protects against metabolic disorders. However, the underlying mechanism by which butyrate modulates hepato-lipid metabolism to a great extent remains unexplored. In this study, we constructed an isolated in vitro model of chicken primary hepatocytes to induce hepatic steatosis by free fatty acids (FFA). Our results demonstrate that treatment with NaB effectively mitigated FFA-induced hepatic steatosis in chicken hepatocytes by inhibiting lipid accumulation, downregulating the mRNA expression of lipo-synthesis-related genes (sterol regulatory element binding transcription factor 1 (SREBF1), acetyl-CoA carboxylase 1(ACC1), fatty acid synthase (FASN), stearoyl-CoA desaturase 1 (SCD1), liver X receptor α (LXRα), 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR)) (P < 0.05), and upregulating the mRNA and protein expression of AMP-activated protein kinase α1 (AMPKα1), peroxisome proliferator-activated receptor α (PPARα), and carnitine palmitoyl-transferase 1A (CPT1A) (P < 0.05). Moreover, AMPK and PPARα inhibitors (Compound C (Comp C) and GW6471, respectively) reversed the protective effects of NaB against FFA-induced hepatic steatosis by blocking the AMPK/PPARα pathway, leading to lipid droplet accumulation and triglyceride (TG) contents in chicken primary hepatocytes. With these findings, NaB can alleviate hepatocyte lipoatrophy injury by activating the AMPK/PPARα pathway, promoting fatty acid oxidation, and reducing lipid synthesis in chicken hepatocytes, potentially being able to provide new ideas for the treatment of FLHS.

Mechanism of Action of the Plateau-Adapted Gene PPARA in COPD.

Chronic obstructive pulmonary disease (COPD) is a complex respiratory disorder influenced by various factors and involving multiple genes. Respiratory dysfunction in COPD patients leads to hypoxia, resulting in limited oxygen uptake. Peroxisome proliferator-activated receptor alpha (PPARA) is a plateau-adapted gene that regulates respiratory function in populations adapted to high-altitude areas through multiple pathways. Interestingly, PPARA expression is higher in long-term inhabiting Tibetan populations that have adapted to the plateau environment. However, in patients with COPD, the expression of PPARA is downregulated, leading to dysregulation of the hypoxia-inducible factor pathway. Moreover, abnormal PPARA expression in lung epithelial cells triggers inflammatory responses, oxidative stress, and disrupted lipid metabolism, thereby exacerbating disease progression. Thus, this paper explored the mechanism underlying the role of plateau-adapted PPARA in COPD, providing essential theoretical insights into the treatment and prevention of COPD in high-altitude regions.

Chaihu Guizhi Ganjiang Decoction attenuates nonalcoholic steatohepatitis by enhancing intestinal barrier integrity and ameliorating PPARα mediated lipotoxicity.

BACKGROUND: Nonalcoholic steatohepatitis (NASH) is a prominent cause of liver-related death that poses a threat to global health and is characterized by severe hepatic steatosis, lobular inflammation, and ballooning degeneration. To date, no Food and Drug Administration-approved medicine is commercially available. The Chaihu Guizhi Ganjiang Decoction (CGGD) shows potential curative effects on regulation of blood lipids and blood glucose, mitigation of organism inflammation, and amelioration of hepatic function. However, the overall regulatory mechanisms underlying its effects on NASH remain unclear. PURPOSE: This study aimed to investigate the efficiency of CGGD on methionine- and choline-deficient (MCD)-induced NASH and unravel its underlying mechanisms. METHODS: A NASH model of SD rats was established using an MCD diet for 8 weeks, and the efficacy of CGGD was evaluated based on hepatic lipid accumulation, inflammatory response, and fibrosis. The effects of CGGD on the intestinal barrier, metabolic profile, and differentially expressed genes (DEGs) profile were analyzed by integrating gut microbiota, metabolomics, and transcriptome sequencing to elucidate its mechanisms of action. RESULTS: In MCD-induced NASH rats, pathological staining demonstrated that CGGD alleviated lipid accumulation, inflammatory cell infiltration, and fibrosis in the hepatic tissue. After CGGD administration, liver index, liver weight, serum alanine aminotransferase (ALT), and aspartate aminotransferase (AST) contents, liver triglycerides (TG), and free fatty acids (FFAs) were decreased, meanwhile, it down-regulated the level of proinflammatory mediators (TNF-α, IL-6, IL-1ß, MCP-1), and up-regulated the level of anti-inflammatory factors (IL-4, IL-10), and the expression of liver fibrosis markers TGFß, Acta2, Col1a1 and Col1a2 were weakened. Mechanistically, CGGD treatment altered the diversity of intestinal flora, as evidenced by the depletion of Allobaculum, Blautia, norank_f_Erysipelotrichaceae, and enrichment of the probiotic genera Roseburia, Lactobacillus, Lachnoclostridium, etc. The colonic histopathological results indicated that the gut barrier damage recovered in the CGGD treatment group, and the expression levels of colonic short-chain fatty acids (SCFAs)-specific receptors FFAR2, FFAR3, and tight junction (TJs) proteins ZO-1, Occludin, Claudin-1 were increased compared with those in the model group. Further metabolomic and transcriptomic analyses suggested that CGGD mitigated the lipotoxicity caused by glycerophospholipid and eicosanoid metabolism disorders by decreasing the levels of PLA2G4A, LPCAT1, COX2, and LOX5. In addition, CGGD could activate the inhibitory lipotoxic transcription factor PPARα, regulate the proteins of FABP1, APOC2, APOA2, and LPL to promote fatty acid catabolism, and suppress the TLR4/MyD88/NFκB pathway to attenuate NASH. CONCLUSION: Our study demonstrated that CGGD improved steatosis, inflammation, and fibrosis on NASH through enhancing intestinal barrier integrity and alleviating PPARα mediated lipotoxicity, which makes it an attractive candidate for potential new strategies for NASH prevention and treatment.

CD24 negativity reprograms mitochondrial metabolism to PPARα and NF-κB-driven fatty acid ß-oxidation in triple-negative breast cancer.

CD24 is a well-characterized breast cancer (BC) stem cell (BCSC) marker. Primary breast tumor cells having CD24-negativity together with CD44-positivity is known to maintain high metastatic potential. However, the functional role of CD24 gene in triple-negative BC (TNBC), an aggressive subtype of BC, is not well understood. While the significance of CD24 in regulating immune pathways is well recognized in previous studies, the significance of CD24 low expression in onco-signaling and metabolic rewiring is largely unknown. Using CD24 knock-down and over-expression TNBC models, our in vitro and in vivo analysis suggest that CD24 is a tumor suppressor in metastatic TNBC. Comprehensive in silico gene expression analysis of breast tumors followed by lipidomic and metabolomic analyses of CD24-modulated cells revealed that CD24 negativity induces mitochondrial oxidative phosphorylation and reprograms TNBC metabolism toward the fatty acid beta-oxidation (FAO) pathway. CD24 silencing activates PPARα-mediated regulation of FAO in TNBC cells. Further analysis using reverse-phase protein array and its validation using CD24-modulated TNBC cells and xenograft models nominated CD24-NF-κB-CPT1A signaling pathway as the central regulatory mechanism of CD24-mediated FAO activity. Overall, our study proposes a novel role of CD24 in metabolic reprogramming that can open new avenues for the treatment strategies for patients with metastatic TNBC.

Cornelian Cherry (Cornus mas L.) Fruit Extract Lowers SREBP-1c and C/EBPα in Liver and Alters Various PPAR-α, PPAR-γ, LXR-α Target Genes in Cholesterol-Rich Diet Rabbit Model.

Cornelian cherry (Cornus mas L.) fruits, abundant in iridoids and anthocyanins, are natural products with proven beneficial impacts on the functions of the cardiovascular system and the liver. This study aims to assess and compare whether and to what extent two different doses of resin-purified cornelian cherry extract (10 mg/kg b.w. or 50 mg/kg b.w.) applied in a cholesterol-rich diet rabbit model affect the levels of sterol regulatory element-binding protein 1c (SREBP-1c) and CCAAT/enhancer binding protein α (C/EBPα), and various liver X receptor-α (LXR-α), peroxisome proliferator-activated receptor-α (PPAR-α), and peroxisome proliferator-activated receptor-γ (PPAR-γ) target genes. Moreover, the aim is to evaluate the resistive index (RI) of common carotid arteries (CCAs) and aortas, and histopathological changes in CCAs. For this purpose, the levels of SREBP-1c, C/EBPα, ATP-binding cassette transporter A1 (ABCA1), ATP-binding cassette transporter G1 (ABCG1), fatty acid synthase (FAS), endothelial lipase (LIPG), carnitine palmitoyltransferase 1A (CPT1A), and adiponectin receptor 2 (AdipoR2) in liver tissue were measured. Also, the levels of lipoprotein lipase (LPL), visceral adipose tissue-derived serine protease inhibitor (Vaspin), and retinol-binding protein 4 (RBP4) in visceral adipose tissue were measured. The RI of CCAs and aortas, and histopathological changes in CCAs, were indicated. The oral administration of the cornelian cherry extract decreased the SREBP-1c and C/EBPα in both doses. The dose of 10 mg/kg b.w. increased ABCA1 and decreased FAS, CPT1A, and RBP4, and the dose of 50 mg/kg b.w. enhanced ABCG1 and AdipoR2. Mitigations in atheromatous changes in rabbits' CCAs were also observed. The obtained outcomes were compared to the results of our previous works. The beneficial results confirm that cornelian cherry fruit extract may constitute a potentially effective product in the prevention and treatment of obesity-related disorders.

Distinct bile acid alterations in response to a single administration of PFOA and PFDA in mice.

Per- and polyfluoroalkyl substances (PFASs), a group of synthetic chemicals that were once widely used for industrial purposes and in consumer products, are widely found in the environment and in human blood due to their extraordinary resistance to degradation. Once inside the body, PFASs can activate nuclear receptors such as PPARα and CAR. The present study aimed to investigate the impact of perfluorooctanoic acid (PFOA) and perfluorodecanoic acid (PFDA) on liver structure and functions, as well as bile acid homeostasis in mice. A single administration of 0.1 mmole/kg of PFDA, not PFOA, elevated serum ALT and bilirubin levels and caused cholestasis in WT mice. PFDA increased total and various bile acid species in serum but decreased them in the liver. Furthermore, in mouse livers, PFDA, not PFOA, down-regulated mRNA expression of uptake transporters (Ntcp, Oatp1a1, 1a4, 1b2, and 2b1) but induced efflux transporters (Bcrp, Mdr2, and Mrp2-4). In addition, PFDA, not PFOA, decreased Cyp7a1, 7b1, 8b1, and 27a1 mRNA expression in mouse livers with concomitant hepatic accumulation of cholesterol. In contrast, in PPARα-null mice, PFDA did not increase serum ALT, bilirubin, or total bile acids, but produced prominent hepatosteatosis; and the observed PFDA-induced expression changes of transporters and Cyps in WT mice were largely attenuated or abolished. In CAR-null mice, the observed PFDA-induced bile acid alterations in WT mice were mostly sustained. These results indicate that, at the dose employed, PFDA has more negative effects than PFOA on liver function. PPARα appears to play a major role in mediating most of PFDA-induced effects, which were absent or attenuated in PPARα-null mice. Lack of PPARα, however, exacerbated hepatic steatosis. Our findings indicate separated roles of PPARα in mediating the adaptive responses to PFDA: protective against hepatosteatosis but exacerbating cholestasis.

GenX analogs exposure induced greater hepatotoxicity than GenX mainly via activation of PPARα pathway while caused hepatomegaly in the absence of PPARα in female mice.

Despite their use as substitutes for perfluorooctanoic acid, the potential toxicities of hexafluoropropylene oxide dimer acid (HFPO-DA, commercial name: GenX) and its analogs (PFDMOHxA, PFDMO2HpA, and PFDMO2OA) remain poorly understood. To assess the hepatotoxicity of these chemicals on females, each chemical was orally administered to female C57BL/6 mice at the dosage of 0.5 mg/kg/d for 28 d. The contribution of peroxisome proliferator-activated receptors (PPARα and γ) and other nuclear receptors involving in these toxic effects of GenX and its analogs were identified by employing two PPAR knockout mice (PPARα-/- and PPARγΔHep) in this study. Results showed that the hepatotoxicity of these chemicals increased in the order of GenX < PFDMOHxA < PFDMO2HpA < PFDMO2OA. The increases of relative liver weight and liver injury markers were significantly much lower in PPARα-/- mice than in PPARα+/+ mice after GenX analog exposure, while no significant differences were observed between PPARγΔHep and its corresponding wildtype groups (PPARγF/F mice), indicating that GenX analog induce hepatotoxicity mainly via PPARα instead of PPARγ. The PPARα-dependent complement pathways were inhibited in PFDMO2HpA and PFDMO2OA exposed PPARα+/+ mice, which might be responsible for the observed liver inflammation. In PPARα-/- mice, hepatomegaly and increased liver lipid content were observed in PFDMO2HpA and PFDMO2OA treated groups. The activated pregnane X receptor (PXR) and constitutive activated receptor (CAR) pathways in the liver of PPARα-/- mice, which were highlighted by bioinformatics analysis, provided a reasonable explanation for hepatomegaly in the absence of PPARα. Our results indicate that GenX analogs could induce more serious hepatotoxicity than GenX whether there is a PPARα receptor or not. These chemicals, especially PFDMO2HpA and PFDMO2OA, may not be appropriate PFOA alternatives.

Fenofibrate alleviates NAFLD by enhancing the PPARα/PGC-1α signaling pathway coupling mitochondrial function.

BACKGROUND: To comprehend the influences of fenofibrate on hepatic lipid accumulation and mitochondrial function-related signaling pathways in mice with non-alcoholic fatty liver disease (NAFLD) secondary to high-fat diets together with free fatty acids-influenced HepG2 cells model. MATERIALS AND METHODS: A random allocation of male 6-week C57BL/6J mice into three groups was done, including controls, model (14 weeks of a high-fat diet), and fenofibrate [similar to the model one with administered 0.04 g/(kg.d) fenofibrate by gavage at 11 weeks for 4 weeks] groups, which contained 10 mice each. This study verified NAFLD pathogenesis via mitochondrial functions in hepatic pathological abnormalities, liver index and weight, body weight, serum biochemical indexes, oxidative stress indicators, mitochondrial function indexes, and related signaling pathways. The effect of fenofibrate intervention was investigated in NAFLD model mice. In vitro, four groups based on HepG2 cells were generated, including controls, the FFA model (1.5 mmol/L FFA incubation for 24 h), LV-PGC-1α intervention (similar to the FFA model one after PPARGC1A lentivirus transfection), and LV control intervention (similar to the FFA model one after negative control lentivirus transfection) groups. The study investigated the mechanism of PGC-1α related to lipid decomposition and mitochondrial biosynthesis by Oil red O staining, colorimetry and western blot. RESULTS: In vivo experiments, a high-fat diet achieved remarkable changes regarding liver weight, liver index, serum biochemical indicators, oxidative stress indicators, liver pathological changes, mitochondrial function indicators, and body weight of the NAFLD model mice while fenofibrate improved the objective indicators. In the HepG2 cells model, the lipid accumulation increased significantly within the FFA model group, together with aggravated hepatocytic damage and boosted oxidative stress levels. Moreover, FFA induced excessive mitosis into fragmented in mitochondrial morphology, ATP content in cells decreased, mtDNA replication fold decreased, the expression of lipid decomposition protein PPARα reduced, mitochondrial biosynthesis related protein PGC-1α, NRF-1 and TFAM decreased. PGC-1α overexpression inhibited lipid deposition by improving mitochondrial biosynthesis and lipid decomposition. CONCLUSION: Fenofibrate up-regulated PPARα/PGC-1α signaling pathway, promoted mitochondrial ß-oxidation, reduced oxidative stress damage and lipid accumulation of liver. PGC-1α overexpression enhanced mitochondrial biosynthesis and ATP production, and reduced HepG2 intracellular accumulation of lipids and oxidative stress.

PPARα is one of the key targets for dendrobine to improve hepatic steatosis in NAFLD.

ETHNOPHARMACOLOGICAL RELEVANCE: Dendrobium nobile Lindl. (DNL) is a traditional Chinese ethnobotanical herb. Dendrobine (DNE) has been designated as a quality indicator for DNL in the Chinese Pharmacopoeia. DNE exhibits various pharmacological activities, including the reduction of blood lipids, regulation of blood sugar levels, as well as anti-inflammatory and antioxidant properties. AIM OF THE STUDY: The objective of this study is to explore the impact of DNE on lipid degeneration in nonalcoholic fatty liver disease (NAFLD) liver cells and elucidate its specific mechanism. The findings aim to offer theoretical support for the development of drugs related to DNL. MATERIALS AND METHODS: We utilized male C57BL/6J mice, aged 6 weeks old, to establish a NAFLD model. This model allowed us to assess the impact of DNE on liver pathology and lipid levels in NAFLD mice. We investigated the mechanism of DNE's regulation of lipid metabolism through RNA-seq analysis. Furthermore, a NAFLD model was established using HepG2 cells to further evaluate the impact of DNE on the pathological changes of NAFLD liver cells. The potential mechanism of DNE's improvement was rapidly elucidated using HT-qPCR technology. These results were subsequently validated using mouse liver samples. Following the in vitro activation or inhibition of PPARα function, we observed changes in DNE's ability to ameliorate pathological changes in NAFLD hepatocytes. This mechanism was further verified through RT-qPCR and Western blot analysis. RESULTS: DNE demonstrated a capacity to enhance serum TC, TG, and liver TG levels in mice, concurrently mitigating liver lipid degeneration. RNA-seq analysis unveiled that DNE primarily modulates the expression of genes related to metabolic pathways in mouse liver. Utilizing HT-qPCR technology, it was observed that DNE markedly regulates the expression of genes associated with the PPAR signaling pathway in liver cells. Consistency was observed in the in vivo data, where DNE significantly up-regulated the expression of PPARα mRNA and its protein level in mouse liver. Additionally, the expression of fatty acid metabolism-related genes (ACOX1, CPT2, HMGCS2, LPL), regulated by PPARα, was significantly elevated following DNE treatment. In vitro experiments further demonstrated that DNE notably ameliorated lipid deposition, peroxidation, and inflammation levels in NAFLD hepatocytes, particularly when administered in conjunction with fenofibrate. Notably, the PPARα inhibitor GW6471 attenuated these effects of DNE. CONCLUSIONS: In summary, DNE exerts its influence on the expression of genes associated with downstream fat metabolism by regulating PPARα. This regulatory mechanism enhances liver lipid metabolism, mitigates lipid degeneration in hepatocytes, and ultimately ameliorates the pathological changes in NAFLD hepatocytes.