Inhibitor GW9662 Research Articles

Nuciferine improves cardiac function in mice subjected to myocardial ischemia/reperfusion injury by upregulating PPAR-γ

Ischemic heart disease and myocardial infarction contribute to the leading cause of death in worldwide. The prevention and management of myocardial ischemia/reperfusion (I/R) injury is an essential part of coronary heart disease surgery and is becoming a major clinical problem in the treatment of ischemic heart disease. Nuciferine has potent anti-inflammatory and antioxidative stress effects, but its role in myocardial ischemia-reperfusion (I/R) is unclear. In this study, we found that nuciferine could reduce the myocardial infarct size in a mouse myocardial ischemia-reperfusion model and improve cardiac function. Furthermore, nuciferine could effectively inhibit hypoxia and reoxygenation (H/R) stimulated apoptosis of primary mouse cardiomyocytes. In addition, nuciferine significantly reduced the level of oxidative stress. The peroxisome proliferator-activated receptor gamma (PPAR-γ) inhibitor GW9662 could reverse the protective effect of nuciferine on cardiomyocytes. These results indicate that nuciferine can inhibit the apoptosis of cardiomyocytes by upregulating PPAR-γ and reducing the I/R-induced myocardial injury in mice.

Nephropathy 1st inhibits renal fibrosis by activating the PPARγ signaling pathway.

Renal fibrosis is a manifestation of kidney injury. Nephropathy 1st is a traditional Chinese herbal medicine that has been used as a therapy for kidney disease, but the underlying mechanisms remain elusive. The aim of this study was to investigate the role and underlying mechanisms of Nephropathy 1st on the progression of kidney disease. In the present study, unilateral ureteral obstruction was performed to establish the renal fibrosis rat model. By hematoxylin-eosin staining and immunohistochemical staining analysis, the severity of renal fibrosis was evaluated in vivo. Serum creatinine (CREA) and urea nitrogen (BUN) were measured by ELISA. The expression levels of Col-I, FN, PPARγ, and Klotho were measured by Western blot in rat NRK-49F cells and in fibrotic rats. GW9662 was used to inhibit PPARγ signaling. Metabonomic analysis showed metabolic differences among groups. Nephropathy 1st administration alleviated the progression of rat renal fibrosis and reduced serum creatinine (Scr) and BUN levels. Mechanistically, Nephropathy 1st promoted the expression of PPARγ and thus activated PPARγ signaling, thereby reducing the pro-fibrotic phenotypes of fibroblasts. The therapeutic effect of Nephropathy 1st was abrogated by the PPARγ inhibitor GW9662. Moreover, Nephropathy 1st normalized the dysregulated lipid metabolism in renal fibrosis rats. In conclusion, Nephropathy 1st alleviates renal fibrosis development in a PPARγ-dependent manner.

Epoxyeicosatrienoic Acids Inhibit the Activation of Murine Fibroblasts by Blocking the TGF-β1-Smad2/3 Signaling in a PPARγ-Dependent Manner.

Background Epoxyeicosatrienoic acids (EETs), the metabolite of arachidonic acid by cytochrome P450 (CYP), reportedly serve as a vital endogenous protective factor in several chronic diseases. EETs are metabolized by soluble epoxide hydrolase (sEH). We have observed that prophylactic blocking sEH alleviates bleomycin- (BLM-) induced pulmonary fibrosis (PF) in mice. However, the underlying mechanism and therapeutic effects of EETs on PF remain elusive. Objective In this study, we investigated the effect of CYP2J2/EETs on the activation of murine fibroblasts and their mechanisms. Results we found that administration of the sEH inhibitor (TPPU) 7 days after the BLM injection also reversed the morphology changes and collagen deposition in the lungs of BLM-treated mice, attenuating PF. Fibroblast activation is regarded as a critical role of PF. Therefore, we investigated the effects of EETs on the proliferation and differentiation of murine fibroblasts. Results showed that the overexpression of CYP2J2 reduced the cell proliferation and the expressions of α-SMA and PCNA induced by transforming growth factor- (TGF-) β1 in murine fibroblasts. Then, we found that EETs inhibited the proliferation and differentiation of TGF-β1-treated-NIH3T3 cells and primary murine fibroblasts. Mechanistically, we found that 14,15-EET disrupted the phosphorylation of Smad2/3 murine fibroblasts by activating PPARγ, which was completely abolished by a PPARγ inhibitor GW9662. Conclusion our study shows that EETs inhibit the activation of murine fibroblasts by blocking the TGF-β1-Smad2/3 signaling in a PPARγ-dependent manner. Regulating CYP2J2-EET-sEH metabolic pathway may be a potential therapeutic option in PF.

Molecular mechanism of benign biliary stricture inhibition by rosiglitazone-activated peroxisome proliferator-activated receptor gamma.

The aim of this study was to investigate whether rosiglitazone-activated peroxisome proliferator-activated receptor gamma can inhibit the occurrence of benign biliary stricture and further elucidate the relevant molecular signaling mechanism. The primary cultured rat biliary fibroblasts following experiments were performed using within the fifth generation cells, which were separated from the bile ducts of Sprague-Dawley rats. The primary cultured rat biliary fibroblasts were co-cultured with 10 ng/mL transforming growth factor-beta 1 for stimulating collagen formation. Competent cells were transfected with siRNA that specifically target Smad3 or connective tissue growth factor to inhibit the expression of the corresponding proteins. The cells were incubated with 10 μmol/L rosiglitazone to activate peroxisome proliferator-activated receptor gamma. The cells were incubated with 10 μmol/L GW9662 in the pretreatment session to inactivate peroxisome proliferator-activated receptor gamma. ELISA was used to determine the levels of connective tissue growth factor and type I collagen in the cell supernatant. Western blotting was used to detect the levels of intracellular p-Smad3/t-Smad3. Rosiglitazone-activated peroxisome proliferator-activated receptor gamma inhibited the secretion of type I collagen induced by transforming growth factor-beta 1. Peroxisome proliferator-activated receptor gamma inhibitor GW9662 could significantly reverse the rosiglitazone-triggered inhibition of transforming growth factor-beta 1-induced type I collagen secretion by suppressing peroxisome proliferator-activated receptor gamma activation (p<0.01). Furthermore, we also found that the activation of peroxisome proliferator-activated receptor gamma was accompanied by the inhibition of transforming growth factor-beta 1-induced Smad3 phosphorylation (p<0.01), increased connective tissue growth factor expression (p<0.01), and production of type I collagen (p<0.01), all of which effects elicited by rosiglitazone could be reversed by peroxisome proliferator-activated receptor gamma inhibitor GW9662. Peroxisome proliferator-activated receptor gamma activated by rosiglitazone inhibits the transforming growth factor-beta1 -induced phosphorylation of Smad3 and the increased connective tissue growth factor expression as well as inhibits the secretion of type I collagen in biliary fibroblasts.

Activation of PPARγ Protects Obese Mice from Acute Lung Injury by Inhibiting Endoplasmic Reticulum Stress and Promoting Mitochondrial Biogenesis.

Objective Obesity-induced endoplasmic reticulum (ER) stress plays a role in increased susceptibility to acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). The activation of peroxisome proliferator-activated receptor-γ (PPARγ) is associated with lung protection and is effective in ameliorating ER stress and mitochondrial dysfunction. The aim of this study was to investigate the expression of PPARγ in the lung tissues of obese mice and explore whether the PPARγ-dependent pathway could mediate decreased ALI/ARDS by regulating ER stress and mitochondrial biogenesis. Methods We determined PPARγ expression in the lung tissues of normal and obese mice. ALI models of alveolar epithelial cells and of obese mice were used and treated with either PPARγ activator rosiglitazone (RSG) or PPARγ inhibitor GW9662. Lung tissue and cell samples were collected to assess lung inflammation and apoptosis, and ER stress and mitochondrial biogenesis were detected. Results PPARγ expression was significantly decreased in the lung tissue of obese mice compared with that in normal mice. Both in vivo and in vitro studies have shown that activation of PPARγ leads to reduced expression of the ER stress marker proteins 78-kDa glucose-regulated protein (GRP78), C/EBP homologous protein (CHOP), and Caspase12. Conversely, expression of the mitochondrial biogenesis-related proteins peroxisome proliferator-activated receptor γ coactivator 1 (PGC-1α), nuclear respiratory factor-1 (NRF-1), and mitochondrial transcription factor A (TFAM) increased. Furthermore, activation of PPARγ is associated with decreased levels of lung inflammation and epithelial apoptosis and increased expression of adiponectin (APN) and mitofusin2 (MFN2). GW9662 bound to PPARγ and blocked its transcriptional activity and then diminished the protective effect of PPARγ on lung tissues. Conclusions PPARγ activation exerts anti-inflammation effects in alveolar epithelia by alleviating ER stress and promoting mitochondrial biogenesis. Therefore, lower levels of PPARγ in the lung tissues of obese mice may lead to an increased susceptibility to ALI.

Magnolol limits NFκB-dependent inflammation by targeting PPARγ relieving retinal ischemia/reperfusion injury

BackgroundGlaucoma is the leading cause of irreversible blindness in the world. Elevated intraocular pressure (IOP) is recognized as one of the most critical factors, but the loss of retinal ganglia cells (RGCs) often persists when IOP is controlled. Recently, a large number of studies focus on the inflammatory and immune responses in the occurrence and development of glaucoma. Magnolol (MAG), the principal ingredient of magnoliae officinalis cortex, has anti-inflammatory effects, but its role and mechanism in retinal protection need to be further studied. MethodsThe neurodegeneration of retina in mice model following ischemia/reperfusion (IR) injury was evaluated by immunohistochemistry, hematoxylin and eosin (H&E) staining and electroretinography (ERG). The inflammation-regulatory effect of MAG was detected by quantitative RT-PCR, western blot, and immunohistochemistry. Peroxisome proliferator-activated receptor-γ (PPARγ) inhibitor assays by H&E staining and western blot were used to test the target and mechanism pathway of MAG. ResultsWe found MAG relieved IR-induced retinal damages and inflammation. Further studies revealed MAG alleviated nuclear factor kappa B (NFκB)-dependent inflammatory process by preserving the expression of NFκB inhibitor alpha (IκBα), and it modulated microglia polarization after IR injury. PPARγ was a primary target of MAG, and treatment with PPARγ inhibitor GW9662 attenuated the neuroprotective and anti-inflammatory effects of MAG. ConclusionsOur findings revealed that MAG inhibits NFκB-dependent inflammatory processes by elevating PPARγ in mice retinas to achieve its neuroprotective role following IR, which suggesting that MAG could be developed to a novel anti-inflammatory therapeutic agent for relieving the progression of glaucoma.

Arisaema heterophyllum Blume Monomer Stigmasterol Targets PPARγ and Inhibits the Viability and Tumorigenicity of Lung Adenocarcinoma Cells NCI-H1975.

To clarify the regulatory effect and molecular mechanism of Arisaema heterophyllum Blume (AhBl) monomer stigmasterol on lung adenocarcinoma in human lung adenocarcinoma cells NCI-H1975 cultured in vitro and in nude mice. Oil red O staining, free fatty acid detection, adenosine triphosphate (ATP), and NADPH were applied to elucidate the regulatory effect of stigmasterol on the energy metabolism of NCI-H1975 cells. Simultaneously, colony formation assay and nude mouse tumorigenesis were performed to clarify the underlying mechanisms of stigmasterol on the proliferation and tumorigenesis of NCI-H1975 cells. Furthermore, peroxisome proliferator-activated receptor gamma (PPARγ) inhibitor GW9662 was supplemented to determine the expression changes of cyclins to clarify the regulation mechanism of stigmasterol. The results revealed that stigmasterol administration markedly inhibited the viability but promoted lipid deposition of NCI-H1975 cells. Meanwhile, the reduction of cell energy metabolism affected cell proliferation and colony formation. qPCR and western blot assays indicated that stigmasterol played a role in regulating the expression of cyclins and PPARγ signaling pathway proteins. Nude mouse tumorigenesis suggested that tumor size and weight in the stigmasterol-treated group were apparently lower as compared with the control group. Tumor tissue cells developed varying degrees of degeneration and large areas of ischemic necrosis presented in the central and peripheral cells. Immunohistochemistry results revealed that Ki67 expression in the stigmasterol group was substantially inhibited, while PPARγ expression was greatly elevated as compared with the control. GW9662 could mediate the inhibitory effect of stigmasterol on NCI-H1975 cells. The current study demonstrated that stigmasterol targeted PPARγ and inhibited the viability and tumorigenicity of lung adenocarcinoma cells NCI-H1975.

Lipid Messenger Phosphatidylinositol-4,5-Bisphosphate Is Increased by Both PPARα Activators and Inhibitors: Relevance for Intestinal Cell Differentiation.

Simple SummaryFibrates, such as fenofibrate, are widely used drugs for dyslipidaemia treatment. It is known that they activate peroxisome proliferator-activated receptor α (PPARα) which serves as a lipid sensor in the organism. This article addresses how activators and inhibitor of the PPARα could affect differentiation of intestinal cells. Carcinogenesis is a disruption of normal differentiation process and colorectal carcinoma is the third most common cancer in terms of incidence, but the secondp in terms of mortality. One of the important signalling pathways in intestinal cell differentiation as well as carcinogenesis is PI3K/Akt/PTEN. We showed that PPARα activators as well as inhibitor affected the levels of one member of this pathway called phosphatidylinositol-4,5-bisphosphate. This molecule is important for formation of microvilli, the essential structures of fully differentiated intestinal cells.We investigated the effects of PPARα activators fenofibrate and WY-14643 as well as the PPARα inhibitor GW6471 on the PI3K/Akt/PTEN pathway of intestinal cell differentiation. Our previous study showed that all these compounds increased the expression of villin, a specific marker of intestinal cell differentiation in HT-29 and Caco2 cells. Our current results confirmed the central role of lipid messenger phosphatidylinositol-4,5-bisphosphate (PIP2), a known player in brush border formation, in mediating the effects of tested PPARα ligands. Although all tested compounds increased its levels, surprisingly, each of them affected different PIP2-metabolizing enzymes, especially the levels of PIP5K1C and PTEN. Moreover, we found a positive relationship between the expression of PPARα itself and PIP2 as well as PIP5K1C. By contrast, PPARα was negatively correlated with PTEN. However, the expression of antigens of interest was independent of PPARα subcellular localization, suggesting that it is not directly involved in their regulation. In colorectal carcinoma tissues we found a decrease in PTEN expression, which was accompanied by a change in its subcellular localization. This change was also observed for the regulatory subunit of PI3K. Taken together, our data revealed that fenofibrate, WY-14643, and GW6471 affected different members of the PI3K/Akt/PTEN pathway. However, these effects were PPARα-independent.

Human Neural Stem Cell Secretome Inhibits Lipopolysaccharide-Induced Neuroinflammation Through Modulating Microglia Polarization by Activating Peroxisome Proliferator-Activated Receptor Gamma

Neuroinflammation is one of the typical events in multiple neurodegenerative diseases, whereas microglia are the critical participants in the pathogenesis of neuroinflammation. Several studies suggest that neural stem cells (NSCs) present immunomodulatory benefits due to their paracrine products, which contain mounting trophic factors. In the current study, the anti-inflammatory effects of NSC secretome (NSC-S) on lipopolysaccharide (LPS)-induced neuroinflammatory models were evaluated in vivo and the underlying mechanism was further investigated in vitro. It was revealed that NSC-S significantly attenuated the severity of LPS-induced behavior disorders and inflammatory response in mice. In vitro studies found that NSC-S significantly promoted the polarization of microglia from proinflammatory M1 to anti-inflammatory M2 phenotype, and reduced the production of proinflammatory cytokines, whereas elevated anti-inflammatory cytokines in BV2 cells. NSC-S promoted peroxisome proliferator-activated receptor gamma (PPAR-γ) pathway activation. However, these effects of NSC-S were abrogated by PPAR-γ inhibitor GW9662. Notably, the fatty acid-binding protein 5 (FABP5) in NSC-S may mediate PPAR-γ activation and inflammation remission. In summary, NSC-S promotes the regression of LPS-induced microglia-mediated inflammation through the PPAR-γ pathway. This function might be achieved through FABP5.

Resveratrol blocks retrotransposition of LINE-1 through PPAR α and sirtuin-6

The retroelement long interspersed element-1 (LINE-1 or L1) comprises about 17% of the human genome. L1 retrotransposition is known to cause genomic instability and related disorders, and resveratrol suppresses this retrotransposition; however, the underlying mechanism is still not elucidated. Recent observations showed that low-molecular-weight compounds might induce L1 retrotransposition through unknown mechanisms. This study aimed to determine polyphenol resveratrol (RV)’s effect on L1-RTP (retrotransposition) in somatic cells. Surprisingly, RV completely blocked L1-RTP. Experiments using the PPARα inhibitor GW6471 or siRNA-mediated PPARα depletion showed that RV-mediated L1-RTP’s inhibition depended on peroxisome proliferator-activated receptor α (PPARα). We demonstrated that RV inhibits p38 and cAMP response element binding protein phosphorylation, which are involved in MAPK signaling, and the L1-ORF1 protein’s chromatin recruitment. Furthermore, RV increased the expression of sirtuin-6 (SIRT6), which inhibited the activation of L1. The sirtuins family, SIRT1, SIRT6, and SIRT7, but not SIRT3, are involved in RV-mediated inhibition of L1-RTP. Overall, our findings suggest that RV directly modulates PPARα-mediated L1-RTP in somatic cells and that MAPK signaling interacts with SIRT6 closely and may play a role in preventing human diseases such as cancer.

Hydrogen sulfide alleviates particulate matter-induced emphysema and airway inflammation by suppressing ferroptosis

BackgroundRedox imbalance is an vital mechanism for COPD. At present, insufficient researches have been conducted on the protective effect of hydrogen sulfide (H2S) on PM-induced COPD. However, whether H2S exerts the anti-injury role by blocking ferroptosis and restoring redox equilibrium remain to be investigated. MethodsHuman lung tissue samples were collected for IHC staining, and the expressions of Nrf2, ferritinophagy- and ferroptosis-related proteins were observed. The WT C57BL/6 and Nrf2 knockout mice models were established with PM(200 μg per mouse). NaHS(Exogenous H2S) was injected intraperitoneally 30 min in advance. Twenty-nine days later, mice lung tissues were evaluated by HE's and PERLS-DAB's staining. Meanwhile, inflammation and oxidative stress indicators and iron levels were assessed by corresponding ELISA kit. Related protein expressions were detected through Western blot. BEAS-2B cells with or without H2S were exposed to PM2.5 for 36 h. Cell viability, mitochondrial morphology, inflammatory cytokines, antioxidant factors, iron levels, autophagic flux and the levels of ROS, LIP ROS, MitoROS, MMP, as well as related protein expressions were detected by specific methods, respectively. In addition, V5-Nrf2, Nrf2 siRNA, Nrf2 inhibitor ML385, PPAR-γ inhibitor GW9662, autophagy inhibitor CQ, iron chelator DFO and ferroptosis inhibitor Fer-1 were used to verify the target signaling pathways. ResultsWe found that the expressions of LIP ROS, ROS, COX2, MDA and other oxidative factors increased, while the antioxidant markers GPX4, GSH and GSH-Px significantly decreased, as well as active iron accumulation in COPD patients, PM-exposured WT and Nrf2-KO mice models and PM2.5-mediated cell models. NaHS pretreatment markedly inhibited PM-induced emphysema and airway inflammation by alleviating ferroptotic changes in vivo and vitro. With the use of V5-Nrf2 overexpression plasmid, Nrf2 siRNA and pathway inhibitors, we found NaHS activates the expressions of Nrf2 and PPAR-γ, and inhibites ferritinophagy makers LC3B, NCOA4 and FTH1 in BEAS-2B cells. Moreover, the anti-ferroptotic effect of NaHS was further verified to be related to the activation of Nrf2 signal in MEF cells. ConclusionThis research suggested that H2S alleviated PM-induced emphysema and airway inflammation via restoring redox balance and inhibiting ferroptosis through regulating Nrf2-PPAR-ferritinophagy signaling pathway.

Quercetin Impedes Th17 Cell Differentiation to Mitigate Arthritis Involving PPARγ-Driven Transactivation of SOCS3 and Redistribution Corepressor SMRT from PPARγ to STAT3.

Quercetin (QU) is one of the most abundant flavonoids in plants and has attracted the attention of researchers because of its remarkable antirheumatoid arthritis (RA) effects and extremely low adverse reactions. However, the underlying mechanism needs further study. Flow cytometry, immunofluorescence, enzyme linked immunosorbent assay （ELISA）, and quantitative real-time polymerase chain reaction （qRT-PCR） reveal the obvious inhibitory effects of QU on Th17 cell differentiation in arthritic mice. More importantly, QU markedly limits the development of Th17 cell polarization, which is virtually compromised by the treatment with peroxisome proliferator activated receptor γ (PPARγ) inhibitor GW9662 and knockdown of PPARγ. Additionally, molecular dynamics simulation and immunofluorescence exhibit QU directly binds to PPARγ and increases PPARγ nuclear translocation. Besides, QU confers its moderation effect on suppressor of cytokine signaling protein (SOCS3)/signal transducer and activator of transcription 3 (STAT3) axis partially depending on PPARγ. Furthermore, coimmunoprecipitation shows QU redistributes the corepressor silencing mediator for retinoid and thyroid-hormone receptors (SMRT) from PPARγ to STAT3. Finally, the inhibition of Th17 response and the antiarthritic effect of QU are nullified by GW9662 treatment in arthritic mice. QU targets PPARγ and consequently inhibits Th17 cell differentiation by dual inhibitory activity of STAT3 to exert antiarthritic effect. The findings facilitate its development and put forth a stage for uncovering the mechanism of other naturally occurring compounds with chemical structures similar to QU.

Short-term treatment with zingerone ameliorates dextran sulfate sodium-induced mouse experimental colitis.

Ulcerative colitis (UC) is a relapsing and chronic inflammatory disease of the gastrointestinal tract, which seriously threatens human health. Zingerone (ZO) has been proven to be effective for many diseases. The purpose of this study is to investigate the protective effects and potential mechanisms of ZO extracted from ginger on dextran sulfate sodium (DSS)-induced mouse ulcerative colitis (UC). The results showed that ZO alleviated the weight loss of UC model mice, reduced the disease activity index scores, and inhibited the shortening of colon length. ZO also improved DSS-induced pathological changes in colon tissue and inhibited the secretion of pro-inflammatory cytokines in colon and mesenteric lymph nodes. Further mechanism analysis found that ZO inhibited DSS-induced nuclear factor-κB pathway activation, and regulated peroxisome proliferator-activated receptor γ (PPARγ) expression. To further explore whether PPARγ was involved in the anti-UC effect of ZO, PPARγ inhibitor GW9662 was used. Although ZO also showed a protective effect on GW9662-treated colitis mice, the protective role was significantly weakened. Importantly, the administration of GW9662 significantly aggravated UC compared with the ZO + DSS group. In addition, we preliminarily found that ZO had the effects of inhibiting DSS-induced oxidative stress, maintaining intestinal barrier, and inhibiting the content of LPS and the population of Escherichia coli. These results indicated that supplementation with ZO might be a new dietary strategy for the treatment of UC. © 2022 Society of Chemical Industry.

Alpha-Asaronol Alleviates Dysmyelination by Enhancing Glutamate Transport Through the Activation of PPARγ-GLT-1 Signaling in Hypoxia-Ischemia Neonatal Rats.

Preterm white matter injury (PWMI) is the most common form of brain damage in premature infants caused by hypoxia-ischemia (HI), inflammation, or excitotoxicity. It is characterized by oligodendrocyte precursor cell (OPC) differentiation disorder and dysmyelination. Our previous study confirmed that alpha-asarone (α-asaronol), a major compound isolated from the Chinese medicinal herb Acorus gramineus by our lab, could alleviate neuronal overexcitation and improve the cognitive function of aged rats. In the present study, we investigated the effect and mechanism of α-asaronol on myelination in a rat model of PWMI induced by HI. Notably, α-asaronol promoted OPC differentiation and myelination in the corpus callosum of PWMI rats. Meanwhile, the concentration of glutamate was significantly decreased, and the levels of PPARγ and glutamate transporter 1 (GLT-1) were increased by α-asaronol treatment. In vitro, it was also confirmed that α-asaronol increased GLT-1 expression and recruitment of the PPARγ coactivator PCG-1a in astrocytes under oxygen and glucose deprivation (OGD) conditions. The PPARγ inhibitor GW9662 significantly reversed the effect of α-asaronol on GLT-1 expression and PCG-1a recruitment. Interestingly, the conditioned medium from α-asaronol-treated astrocytes decreased the number of OPCs and increased the number of mature oligodendrocytes. These results suggest that α-asaronol can promote OPC differentiation and relieve dysmyelination by regulating glutamate levels via astrocyte PPARγ-GLT-1 signaling. Although whether α-asaronol binds to PPARγ directly or indirectly is not investigated here, this study still indicates that α-asaronol may be a promising small molecular drug for the treatment of myelin-related diseases.

Curcumin attenuates inflammation of Macrophage-derived foam cells treated with Poly-L-lactic acid degradation via PPAR\u03b3 signaling pathway

Poly-L-lactic acid (PLLA) is considered to be a promising candidate material for biodegradable vascular scaffolds (BVS) in percutaneous coronary intervention (PCI). But, PLLA-BVS also faces the challenge of thrombosis (ST) and in-stent restenosis (ISR) caused by in-stent neo-atherosclerosis (ISNA) associated with inflammatory reactions in macrophage-derived foam cells. Our previous studies have confirmed that curcumin alleviates PLLA-induced injury and inflammation in vascular endothelial cells, but it remains unclear whether curcumin can alleviate the effect of inflammatory reactions in macrophage-derived foam cells while treated with degraded product of PLLA. In this study, PLLA-BVS was implanted in the porcine coronary artery to examine increased macrophages and inflammatory cytokines such as NF-κb and TNF-α by histology and immunohistochemistry. In vitro, macrophage-derived foam cells were induced by Ox-LDL and observed by Oil Red Staining. Foam cells were treated with pre-degraded PLLA powder, curcumin and PPARγ inhibitor GW9662, and the expression of IL-6, IL-10, TNF-α, NF-κb, PLA2 and PPARγ were investigated by ELISA or RT-qPCR. This study demonstrated that the macrophages and inflammatory factors increased after PLLA-BVS implantation in vivo, and foam cells derived from macrophages promoted inflammation by products of PLLA degradation in vitro. This present study was found that the inflammation of foam cells at the microenvironment of PLLA degraded products were significantly increased, and curcumin can attenuate the inflammation caused by the PLLA degradation via PPARγ signal pathway. In addition, curcumin should be further studied experimentally in vivo experiments on animal models as a potential therapeutic to reduce ISNA of PLLA-BVS.Graphical abstract

Esculentoside A alleviates cognitive deficits and amyloid pathology through peroxisome proliferator-activated receptor γ-dependent mechanism in an Alzheimer's disease model

BackgroundAlzheimer's disease (AD) is characterized clinically by cognitive deficits and pathologically by amyloid-β (Aβ) deposition and tau aggregation, as well as the brain atrophy. Esculentoside A (EsA), a neuroprotective saponin, is isolated from Phytolacca esculenta and shows potent health-promoting effects in a variety of experimental models. However, there are minimal reports on the effects of EsA on triple transgenic AD mice. PurposeThe current research aimed at investigating the protective effects and underlying mechanisms of EsA on the mitigation of cognitive deficits and pathology in triple transgenic AD mice. MethodsTriple transgenic AD mice (3 × Tg-AD) of 8 months old received intraperitoneal treatment of 5 or 10 mg/kg EsA for 8 consecutive weeks. Morris water maze test and open field test were made to evaluate the cognitive function and degree of anxiety of the mice. Liquid chromatography with tandem mass spectrometry analysis was performed to characterize and to quantify EsA in the blood and brain of mice. Immunofluorescence assay and Western blot were adopted to measure the levels of peroxisome proliferator-activated receptor gamma (PPARγ) and key proteins in Aβ pathology, ER stress- and apoptosis-associated pathways. The combination of EsA with PPARγ were theoretically calculated by molecular docking programs and experimentally confirmed by the bio-layer interferometry technology. ResultsSupplemental EsA could improve the cognitive deficits of 3 × Tg-AD mice. EsA penetrated the brain-blood barrier to exert a strong effect on AD mice, evidenced as decreasing Aβ generation, reducing the degrees of oxidative and ER stress, and mitigating neuronal apoptosis through the increase of PPARγ expression. In the culture of primary neurons, addition of PPARγ inhibitor GW9662 eliminated the effects of EsA on AD pathologies. Direct combination of EsA with PPARγ were demonstrated by molecular docking programs and bio-layer interferometry technology. ConclusionsFor the first time, these outcomes revealed that EsA could penetrate the brain-blood barrier to exert a strong effect on ameliorating cognitive deficits in 3 × Tg-AD mice and exert neuroprotective effects toward AD pathology via PPARγ-dependent mechanism.

Heme Oxygenase-1 Inhibits the Proliferation of Hepatic Stellate Cells by Activating PPARγ and Suppressing NF-κB.

Background Hepatic stellate cells (HSCs) are reported to play significant roles in the development of liver fibrosis. Heme oxygenase-1 (HO-1) is a key rate-limiting enzyme, which could decrease collagen synthesis and liver damage. Nevertheless, it was yet elusive towards the function and mechanism of HO-1. Methods An HO-1 inducer Hemin or an HO-1 inhibitor ZnPP-IX was used to treat the activated HSC-T6, respectively. MTT assay was adopted to detect cell proliferation. Immunocytochemical staining was employed to test the levels of alpha-smooth muscle actin (α-SMA), peroxisome proliferator-activated receptor-γ (PPARγ), and nuclear factor-kappa B (NF-kappa B) levels in HSC-T6. HO-1, PPARγ, and NF-κB expression levels were measured by qRT-PCR and Western blotting. ELISA was then used to detect the levels of transforming growth factor- (TGF-) beta 1 (TGF-β1), interleukin-6 (IL-6), serum hyaluronic acid (HA), and serum type III procollagen aminopeptide (PIIIP). Results HSC-T6 proliferation was inhibited in Hemin-treated HSCs. The levels of α-SMA, HA, and PIIIP and the production of ECM were lower in Hemin-treated HSCs, whereas those could be rescued by ZnPP-IX. NF-κB activation was decreased, but PPARγ expression was increased after HO-1 upregulation. Furthermore, the levels of TGF-β1 and IL-6, which were downstream of activated NF-κB in HSC-T6, were reduced. The PPAR-specific inhibitor GW9662 could block those mentioned effects. Conclusions Our data demonstrated that HO-1 induction could inhibit HSC proliferation and activation by regulating PPARγ expression and NF-κB activation directly or indirectly, which makes it a promising therapeutic target for liver fibrosis.

The Study of Yin-Chen-Hao-Tang Preventing and Treating Alcoholic Fatty Liver Disease through PPAR Signaling Pathway Based on Network Pharmacology and RNA-Seq Transcriptomics.

Background Alcoholic fatty liver disease (AFLD) is the first stage of the alcoholic liver disease course. Yin-Chen-Hao-Tang (YCHT) has a good clinical effect on the treatment of AFLD, but its molecular mechanism has not been elucidated. In this study, we tried to explore the molecular mechanism of YCHT in improving hepatocyte steatosis in AFLD mice through network pharmacology and RNA sequencing (RNA-Seq) transcriptomics. Methods Network pharmacological methods were used to analyze the potential therapeutic signaling pathways and targets of YCHT on AFLD. Then, the AFLD mice model was induced and YCHT was administered concurrently. Liver injury was measured by serum alanine aminotransferase (ALT) activity and liver tissue H&E staining, and liver steatosis was determined by serum triglyceride (TG) level and liver tissue Oil Red staining. The molecular mechanism of YCHT on prevention and treatment of mice AFLD was investigated according to the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of the differential expression genes data obtained by liver tissue RNA-Seq. Finally, ethanol-induced AFLD AML12 hepatocyte model was established, YCHT with or without PPARα agonist pemafibrate or PPARγ inhibitor GW9662 was administered, Nile Red fluorescent staining was used to evaluate steatosis levels in AML12 hepatocytes, and qRT-PCR was used to detect PPARα and PPARγ gene expression. Results The results of network pharmacology analysis showed that YCHT may exert its pharmacological effect on AFLD through 312 potential targets which are involved in many signaling pathways including the PPAR signaling pathway. AFLD mice experiments results showed that YCHT markedly decreased mice serum ALT activity and serum TG levels. YCHT also significantly improved alcohol-induced hepatic injury and steatosis in mice livers. Furthermore, KEGG pathway enrichment results of RNA-Seq showed that the PPAR signaling pathway should be the most relevant pathway of YCHT in the prevention and treatment of AFLD. AFLD hepatocyte model experiment results showed that YCHT could remarkably reduce hepatocyte steatosis through reducing PPARγ expression and increasing PPARα expression. Conclusions Our study discovered that PPARγ and PPARα are the key targets and the PPAR signaling pathway is the main signaling pathway for YCHT to prevent and treat AFLD.

PPARα/γ signaling pathways are involved in Chlamydia pneumoniae-induced foam cell formation via upregulation of SR-A1 and ACAT1 and downregulation of ABCA1/G1

Chlamydia pneumoniae (Cpn) has been reported to be involved in the pathogenesis of early atherosclerosis by inducing macrophage-derived foam cell formation in the presence of low-density lipoprotein (LDL). However, the biochemical mechanisms underlying Cpn-induced foam cell formation are still not fully elucidated. The present study showed that in LDL-treated THP-1-derived macrophages, Cpn not only upregulated the expression of scavenger receptor A1 (SR-A1) and acyl-coenzyme A: cholesterol acyltransferase 1 (ACAT1), but it also downregulated the expression of ATP binding cassette transporters (ABCA1 and ABCG1) at both the mRNA and protein levels. These processes facilitated cholesterol accumulation and promoted macrophage-derived foam cell formation. Treatment with the peroxisome proliferator-activated receptor (PPAR)-γ agonist rosiglitazone or the PPARα agonist fenofibrate decreased the number of foam cells induced by Cpn, while the PPARγ antagonist GW9662, the PPARα antagonist MK886, or PPARα/γ siRNAs enhanced the effect of Cpn on foam cell formation and gene expression of SR-A1, ACAT1, and ABCA1/G1. Moreover, the PPARγ agonist rosiglitazone reversed the downregulation of CD36 by Cpn, while PPARγ siRNA and the PPARγ inhibitor GW9662 further suppressed CD36 expression. However, the PPARα agonist, inhibitor, and siRNA all showed no effect on CD36 expression. In conclusion, the PPARα and PPARγ pathways are both involved in Cpn-induced macrophage-derived foam cell formation by upregulating SR-A1 and ACAT1 and downregulating ABCA1/G1 expression.

Moracin D induces apoptosis in prostate cancer cells via activation of PPAR gamma/PKC delta and inhibition of PKC alpha.

Herein, apoptotic mechanism of Moracin D was explored in prostate cancer cells in association with peroxisome proliferator-activated receptor gamma (PPAR-γ)-related signaling involved in lipid metabolism. Moracin D augmented cytotoxicity and sub G1 population in PC3 and DU145 prostate cancer cells, while DU145 cells were more susceptible to Moracin D than PC3 cells. Moracin D attenuated the expression of caspase-3, poly (ADP-ribose) polymerase (PARP), B-cell lymphoma 2 (Bcl-2), and B-cell lymphoma-extra-large (Bcl-xL) in DU145 cells. Consistently, Moracin D significantly augmented the number of terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive cells in DU145 cells. Interestingly, Moracin D activated PPAR-γ and phospho-protein kinase C delta (p-PKC-δ) and inhibited phospho-protein kinase C alpha (p-PKC-α) in DU145 cells. Furthermore, STRING bioinformatic analysis reveals that PPAR-γ interacts with nuclear factor-κB (NF-κB) that binds to PKC-α/PKC-δ or protein kinase B (AKT) or extracellular signal-regulated kinase (ERK). Indeed, Moracin D decreased phosphorylation of NF-κB, ERK, and AKT in DU145 cells. Conversely, PPAR-γ inhibitor GW9662 reduced the apoptotic ability of Moracin D to activate caspase 3 and PARP in DU145 cells. Taken together, these findings provide a novel insight that activation of PPAR-γ/p-PKC-δ and inhibition of p-PKC-α are critically involved in Moracin D-induced apoptosis in DU145 prostate cancer cells.