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Biomolecules Aug 2023The number of patients with nonalcoholic fatty liver disease (NAFLD)/nonalcoholic steatohepatitis (NASH) is increasing globally and is raising serious concerns regarding... (Review)
Review
The number of patients with nonalcoholic fatty liver disease (NAFLD)/nonalcoholic steatohepatitis (NASH) is increasing globally and is raising serious concerns regarding the increasing medical and economic burden incurred for their treatment. The progression of NASH to more severe conditions such as cirrhosis and hepatocellular carcinoma requires liver transplantation to avoid death. Therefore, therapeutic intervention is required in the NASH stage, although no therapeutic drugs are currently available for this. Several anti-NASH candidate drugs have been developed that enable treatment via the modulation of distinct signaling cascades and include a series of drugs targeting peroxisome proliferator-activated receptor (PPAR) subtypes (PPARα/δ/γ) that are considered to be attractive because they can regulate both systemic lipid metabolism and inflammation. Multiple PPAR dual/pan agonists have been developed but only a few of them have been evaluated in clinical trials for NAFLD/NASH. Herein, we review the current clinical trial status and future prospects of PPAR-targeted drugs for treating NAFLD/NASH. In addition, we summarize our recent findings on the binding modes and the potencies/efficacies of several candidate PPAR dual/pan agonists to estimate their therapeutic potentials against NASH. Considering that the development of numerous PPAR dual/pan agonists has been abandoned because of their serious side effects, we also propose a repositioning of the already approved, safety-proven PPAR-targeted drugs against NAFLD/NASH.
Topics: Humans; Carcinoma, Hepatocellular; Drug-Related Side Effects and Adverse Reactions; Hypoglycemic Agents; Liver Neoplasms; Non-alcoholic Fatty Liver Disease; PPAR alpha; Clinical Trials as Topic
PubMed: 37627329
DOI: 10.3390/biom13081264 -
Acta Biochimica Et Biophysica Sinica Aug 2023Mounting evidence demonstrates that hydrogen sulfide (H S) promotes anti-inflammatory molecules and inhibits pro-inflammatory cytokines in endothelial cells (ECs). This...
Mounting evidence demonstrates that hydrogen sulfide (H S) promotes anti-inflammatory molecules and inhibits pro-inflammatory cytokines in endothelial cells (ECs). This study aims to investigate the favorable action of H S on endothelial function in senescence by inhibiting the production of inflammatory molecules. Senescent ECs exhibit a reduction in H S, endothelial nitric oxide synthase (eNOS) and peroxisome proliferator-activated receptor δ (PPARδ), coupled with increased inflammatory molecules, sodium glucose transporter type 2 (SGLT2) and phosphorylation of STAT3, which could be reversed by the administration of a slow but sustained release agent of H S, GYY4137. Decreased production of eNOS and upregulated p-STAT3 and SGLT2 levels in senescent ECs are reversed by replenishment of the SGLT2 inhibitor EMPA and the PPARδ agonist GW501516. The PPARδ antagonist GSK0660 attenuates eNOS expression and increases the production of p-STAT3 and SGLT2. However, supplementation with GYY4137 has no beneficial effect on GSK0660-treated ECs. GYY4137, GW501516 and EMPA preserve endothelial-dependent relaxation (EDR) in D-gal-treated aortae, while GSK0660 destroys aortic relaxation even with GYY4137 supplementation. In summary, senescent ECs manifest aggravated the expressions of the inflammatory molecules SGLT2 and p-STAT3 and decreased the productions of PPARδ, eNOS and CSE. H S ameliorates endothelial dysfunction through the anti-inflammatory effect of the PPARδ/SGLT2/p-STAT3 signaling pathway in senescent ECs and may be a potential therapeutic target for anti-ageing treatment.
Topics: Humans; Endothelial Cells; PPAR delta; Hydrogen Sulfide; Sodium-Glucose Transporter 2; Inflammation; STAT3 Transcription Factor
PubMed: 37587757
DOI: 10.3724/abbs.2023156 -
Gastric Cancer : Official Journal of... Nov 2023Peroxisome proliferator-activated receptor delta (PPARδ) promotes inflammation and carcinogenesis in many organs, but the underlying mechanisms remains elusive. In...
BACKGROUND
Peroxisome proliferator-activated receptor delta (PPARδ) promotes inflammation and carcinogenesis in many organs, but the underlying mechanisms remains elusive. In stomachs, PPARδ significantly increases chemokine Ccl20 expression in gastric epithelial cells while inducing gastric adenocarcinoma (GAC). CCR6 is the sole receptor of CCL20. Here, we examine the role of PPARδ-mediated Ccl20/Ccr6 signaling in GAC carcinogenesis and investigate the underlying mechanisms.
METHODS
The effects of PPARδ inhibition by its specific antagonist GSK3787 on GAC were examined in the mice with villin-promoter-driven PPARδ overexpression (Ppard). RNAscope Duplex Assays were used to measure Ccl20 and Ccr6 levels in stomachs and spleens. Subsets of stomach-infiltrating immune cells were measured via flow cytometry or immunostaining in Ppard mice fed GSK3787 or control diet. A panel of 13 optimized proinflammatory chemokines in mouse sera were quantified by an enzyme-linked immunosorbent assay.
RESULTS
GSK3787 significantly suppressed GAC carcinogenesis in Ppard mice. PPARδ increased Ccl20 level to chemoattract Ccr6 immunosuppressive cells, including tumor-associated macrophages, myeloid-derived suppressor cells and T regulatory cells, but decreased CD8 T cells in gastric tissues. GSK3787 suppressed PPARδ-induced gastric immunosuppression by inhibiting Ccl20/Ccr6 axis. Furthermore, Ccl20 protein levels increased in sera of Ppard mice starting at the age preceding gastric tumor development and further increased with GAC progression as the mice aged. GSK3787 decreased the PPARδ-upregulated Ccl20 levels in sera of the mice.
CONCLUSIONS
PPARδ dysregulation of Ccl20/Ccr6 axis promotes GAC carcinogenesis by remodeling gastric tumor microenvironment. CCL20 might be a potential biomarker for the early detection and progression of GAC.
Topics: Humans; Animals; Mice; Chemokine CCL20; PPAR delta; Stomach Neoplasms; CD8-Positive T-Lymphocytes; Tumor Microenvironment; Carcinogenesis; Adenocarcinoma; Receptors, CCR6
PubMed: 37572185
DOI: 10.1007/s10120-023-01418-w -
International Journal of Molecular... Jul 2023Obesity is defined as a dampness-heat syndrome in traditional Chinese medicine. Coptidis Rhizoma is an herb used to clear heat and eliminate dampness in obesity and its...
Obesity is defined as a dampness-heat syndrome in traditional Chinese medicine. Coptidis Rhizoma is an herb used to clear heat and eliminate dampness in obesity and its complications. Berberine (BBR), the main active compound in Coptidis Rhizoma, shows anti-obesity effects. Peroxisome proliferator-activated receptors (PPARs) are a group of nuclear receptor proteins that regulate the expression of genes involved in energy metabolism, lipid metabolism, inflammation, and adipogenesis. However, whether PPARs are involved in the anti-obesity effect of BBR remains unclear. As such, the aim of this study was to elucidate the role of PPARs in BBR treatment on obesity and the underlying molecular mechanisms. Our data showed that BBR produced a dose-dependent regulation of the levels of PPARγ and PPARδ but not PPARα. The results of gene silencing and specific antagonist treatment demonstrated that PPARδ is key to the effect of BBR. In 3T3L1 preadipocytes, BBR reduced lipid accumulation; in high-fat-diet (HFD)-induced obese mice, BBR reduced weight gain and white adipose tissue mass and corrected the disturbed biochemical parameters, including lipid levels and inflammatory and oxidative markers. Both the in vitro and in vivo efficacies of BBR were reversed by the presence of a specific antagonist of PPARδ. The results of a mechanistic study revealed that BBR could activate PPARδ in both 3T3L1 cells and HFD mice, as evidenced by the significant upregulation of PPARδ endogenous downstream genes. After activating by BBR, the transcriptional functions of PPARδ were invoked, exhibiting negative regulation of CCAAT/enhancer-binding protein α (Cebpα) and Pparγ promoters and positive mediation of heme oxygenase-1 (Ho-1) promoter. In summary, this is the first report of a novel anti-obesity mechanism of BBR, which was achieved through the PPARδ-dependent reduction in lipid accumulation.
Topics: Animals; Mice; PPAR delta; Berberine; Drugs, Chinese Herbal; PPAR gamma; Obesity; Lipids; Lipid Metabolism
PubMed: 37511356
DOI: 10.3390/ijms241411600 -
International Journal of Molecular... Jul 2023Transforming growth factor-β (TGF-β)/Smad3 signaling has been shown to play important roles in fibrotic and inflammatory diseases. However, the role of Smad3 in...
Transforming growth factor-β (TGF-β)/Smad3 signaling has been shown to play important roles in fibrotic and inflammatory diseases. However, the role of Smad3 in dyslipidemia and non-alcoholic fatty liver disease (NAFLD) in type 2 diabetes remains unclear, and whether targeting Smad3 has a therapeutic effect on these metabolic abnormalities remains unexplored. These topics were investigated in this study in Smad3 knockout (KO)- mice and by treating mice with a Smad3-specific inhibitor SIS3. Compared to Smad3 wild-type (WT)- mice, Smad3 KO- mice were protected against dyslipidemia and NAFLD. Similarly, treatment of mice with SIS3 at week 4 before the onset of type 2 diabetes until week 12 was capable of lowering blood glucose levels and improving diabetic dyslipidemia and NAFLD. In addition, using RNA-sequencing, the potential Smad3-target genes related to lipid metabolism was identified in the liver tissues of Smad3 KO/WT mice, and the regulatory mechanisms were investigated. Mechanistically, we uncovered that Smad3 targeted peroxisome proliferator-activated receptor delta (PPARδ) to induce dyslipidemia and NAFLD in mice, which was improved by genetically deleting and pharmacologically inhibiting Smad3.
Topics: Animals; Mice; Diabetes Mellitus, Type 2; Liver; Mice, Inbred C57BL; Mice, Inbred Strains; Mice, Knockout; Non-alcoholic Fatty Liver Disease; PPAR delta; Smad3 Protein
PubMed: 37511155
DOI: 10.3390/ijms241411396 -
Molecular Psychiatry Oct 2023Peroxisome proliferator-activated receptors (PPARs) are a family of nuclear receptors that regulate gene expression. Δ-tetrahydrocannabinol (Δ-THC) is a PPARγ agonist...
Peroxisome proliferator-activated receptors (PPARs) are a family of nuclear receptors that regulate gene expression. Δ-tetrahydrocannabinol (Δ-THC) is a PPARγ agonist and some endocannabinoids are natural activators of PPARα and PPARγ. However, little is known regarding their cellular distributions in the brain and functional roles in cannabinoid action. Here, we first used RNAscope in situ hybridization and immunohistochemistry assays to examine the cellular distributions of PPARα and PPARγ expression in the mouse brain. We found that PPARα and PPARγ are expressed in ~70% of midbrain dopamine (DA) neurons. In the amygdala, PPARα is expressed in ~60% of glutamatergic neurons, while PPARγ is expressed in ~60% of GABA neurons. However, no PPARα/γ signal was detected in GABA neurons in the nucleus accumbens. We then used a series of behavioral assays to determine the functional roles of PPARα/γ in the CNS effects of Δ-THC. We found that optogenetic stimulation of midbrain DA neurons was rewarding as assessed by optical intracranial self-stimulation (oICSS) in DAT-cre mice. Δ-THC and a PPARγ (but not PPARα) agonist dose-dependently inhibited oICSS. Pretreatment with PPARα or PPARγ antagonists attenuated the Δ-THC-induced reduction in oICSS and Δ-THC-induced anxiogenic effects. In addition, a PPARγ agonist increased, while PPARα or PPARγ antagonists decreased open-field locomotion. Pretreatment with PPARα or PPARγ antagonists potentiated Δ-THC-induced hypoactivity and catalepsy but failed to alter Δ-THC-induced analgesia, hypothermia and immobility. These findings provide the first anatomical and functional evidence supporting an important role of PPARα/γ in DA-dependent behavior and cannabinoid action.
Topics: Mice; Animals; PPAR alpha; Dopamine; Cannabinoids; PPAR gamma; Dronabinol; Dopaminergic Neurons; Mesencephalon
PubMed: 37479780
DOI: 10.1038/s41380-023-02182-0 -
Scientific Reports Jul 2023There is great interest on medium chain fatty acids (MCFA) for cardiovascular health. We explored the effects of MCFA on the expression of lipid metabolism and...
There is great interest on medium chain fatty acids (MCFA) for cardiovascular health. We explored the effects of MCFA on the expression of lipid metabolism and inflammatory genes in macrophages, and the extent to which they were mediated by the nuclear receptor peroxisome proliferator-activated receptor beta/delta (PPAR β/δ). J774A.1 murine macrophages were exposed to octanoate or decanoate as MCFA, a long-chain fatty acid control (palmitate), or the PPAR β/δ agonist GW501516, with or without lipopolysaccharide (LPS) stimulation, and with or without an siRNA-induced knockdown of PPAR β/δ. MCFA increased the expression of Plin2, encoding a lipid-droplet associated protein with anti-inflammatory effects in macrophages, in a partially PPAR β/δ-dependent manner. Both MCFA stimulated expression of the cholesterol efflux pump ABCA1, more pronouncedly under LPS stimulation and in the absence of PPAR β/δ. Octanoate stimulated the expression of Pltp, encoding a phospholipid transfer protein that aids ABCA1 in cellular lipid efflux. Only palmitate increased expression of the proinflammatory genes Il6, Tnf, Nos2 and Mmp9. Non-stimulated macrophages exposed to MCFA showed less internalization of fluorescently labeled lipoproteins. MCFA influenced the transcriptional responses of macrophages favoring cholesterol efflux and a less inflammatory response compared to palmitate. These effects were partially mediated by PPAR β/δ.
Topics: Mice; Animals; PPAR delta; PPAR-beta; Caprylates; Cell Line; Lipopolysaccharides; Macrophages; Fatty Acids; Cholesterol; Palmitates
PubMed: 37463952
DOI: 10.1038/s41598-023-38700-x -
Cell Reports Jul 2023Relapse of acute myeloid leukemia (AML) remains a significant concern due to persistent leukemia-initiating stem cells (LICs) that are typically not targeted by most...
Relapse of acute myeloid leukemia (AML) remains a significant concern due to persistent leukemia-initiating stem cells (LICs) that are typically not targeted by most existing therapies. Using a murine AML model, human AML cell lines, and patient samples, we show that AML LICs are sensitive to endogenous and exogenous cyclopentenone prostaglandin-J (CyPG), Δ-PGJ, and 15d-PGJ, which are increased upon dietary selenium supplementation via the cyclooxygenase-hematopoietic PGD synthase pathway. CyPGs are endogenous ligands for peroxisome proliferator-activated receptor gamma and GPR44 (CRTH2; PTGDR2). Deletion of GPR44 in a mouse model of AML exacerbated the disease suggesting that GPR44 activation mediates selenium-mediated apoptosis of LICs. Transcriptomic analysis of GPR44 LICs indicated that GPR44 activation by CyPGs suppressed KRAS-mediated MAPK and PI3K/AKT/mTOR signaling pathways, to enhance apoptosis. Our studies show the role of GPR44, providing mechanistic underpinnings of the chemopreventive and chemotherapeutic properties of selenium and CyPGs in AML.
Topics: Humans; Mice; Animals; Phosphatidylinositol 3-Kinases; Selenium; Leukemia, Myeloid, Acute; Signal Transduction; Cell Line
PubMed: 37459233
DOI: 10.1016/j.celrep.2023.112794 -
ELife Jul 2023Decidualization is a process in which endometrial stromal fibroblasts differentiate into specialized secretory decidual cells and essential for the successful...
Decidualization is a process in which endometrial stromal fibroblasts differentiate into specialized secretory decidual cells and essential for the successful establishment of pregnancy. The underlying mechanism during decidualization still remains poorly defined. Because decidualization and fibroblast activation share similar characteristics, this study was to examine whether fibroblast activation is involved in decidualization. In our study, fibroblast activation-related markers are obviously detected in pregnant decidua and under in vitro decidualization. ACTIVIN A secreted under fibroblast activation promotes in vitro decidualization. We showed that arachidonic acid released from uterine luminal epithelium can induce fibroblast activation and decidualization through PGI and its nuclear receptor PPARδ. Based on the significant difference of fibroblast activation-related markers between pregnant and pseudopregnant mice, we found that embryo-derived TNF promotes CPLA phosphorylation and arachidonic acid release from luminal epithelium. Fibroblast activation is also detected under human in vitro decidualization. Similar arachidonic acid-PGI-PPARδ-ACTIVIN A pathway is conserved in human endometrium. Collectively, our data indicate that embryo-derived TNF promotes CPLA phosphorylation and arachidonic acid release from luminal epithelium to induce fibroblast activation and decidualization.
Topics: Pregnancy; Female; Humans; Animals; Mice; Decidua; PPAR delta; Arachidonic Acid; Endometrium; Fibroblasts; Stromal Cells
PubMed: 37458359
DOI: 10.7554/eLife.82970 -
Kidney International Reports Jul 2023Peroxisome proliferator-activated receptor δ (PPARδ) plays a central role in modulating mitochondrial function in ischemia-reperfusion injury. The novel PPARδ...
INTRODUCTION
Peroxisome proliferator-activated receptor δ (PPARδ) plays a central role in modulating mitochondrial function in ischemia-reperfusion injury. The novel PPARδ modulator, ASP1128, was evaluated.
METHODS
A randomized, double-blind, placebo-controlled, biomarker assignment-driven, multicenter study was performed in adult patients at risk for acute kidney injury (AKI) following cardiac surgery, examining efficacy and safety of a 3-day, once-daily intravenous dose of 100 mg ASP1128 versus placebo (1:1). AKI risk was based on clinical characteristics and postoperative urinary biomarker (TIMP2)•(IGFBP7). The primary end point was the proportion of patients with AKI based on serum creatinine within 72 hours postsurgery (AKI-SCr72h). Secondary endpoints included the composite end point of major adverse kidney events (MAKE: death, renal replacement therapy, and/or ≥25% reduction of estimated glomerular filtration rate [eGFR]) at days 30 and 90).
RESULTS
A total of 150 patients were randomized and received study medication (81 placebo, 69 ASP1128). Rates of AKI-SCr72h were 21.0% and 24.6% in the placebo and ASP1128 arms, respectively ( = 0.595). Rates of moderate/severe AKI (stage 2/3 AKI-SCr and/or stage 3 AKI-urinary output criteria) within 72 hours postsurgery were 19.8% and 23.2%, respectively ( = 0.609). MAKE occurred within 30 days in 11.1% and 13.0% in the placebo and ASP1128 arms ( = 0.717), respectively; and within 90 days in 9.9% and 15.9% in the placebo and ASP1128 arms ( = 0.266), respectively. No safety issues were identified with ASP1128 treatment, but rates of postoperative atrial fibrillation were lower (11.6%) than in the placebo group (29.6%).
CONCLUSION
ASP1128 was safe and well-tolerated in patients at risk for AKI following cardiac surgery, but it did not show efficacy in renal endpoints.
PubMed: 37441472
DOI: 10.1016/j.ekir.2023.04.004