Vaticanol C, a resveratrol tetramer, activates PPARα and PPARβ/δ in vitro and in vivo

Chemical basis of pregnane X receptor activators in the herbal supplement Gancao (licorice)

Because AMPKα2 is a critical signal in the regulation of muscle metabolism, we sought to determine if muscle AMPKα2 deletion would exacerbate the loss of insulin sensitivity, induced by high fat diet (HFD), as it pertains to the regulation of fatty acid (FA) metabolism. Male C57BL/6 mice (8–12 wks), wild‐type (WT) or dominant negative (DN) AMPKα2 in heart and skeletal muscle, were fed control diet (CD; 12%fat) or HFD (60%fat). After 6 wks, hindlimbs of CD (n=10) and HFD (n=10) mice were perfused (550μM palmitate, 6mM glucose, [1‐14C]palmitate) ±450μU insulin (IS). CD (n=8) and HFD (n=8) muscles were used for basal protein expression. In CD, AMPKα2 deletion did not affect basal FA uptake (FAU), but it increased basal FA oxidation (FAO) by 81% and α2 deletion prevented the IS increase in FAU and decrease in FAO. HFD abolished the IS increase in FAU and decrease in FAO in WT. In HFD, α2 deletion increased basal FAU by 139% (P<0.05) but did not affect IS FAU nor FAO (P>0.05). IS SIRT1 activity was higher in HFD‐DN than HFD‐WT (P<0.05). Neither DN nor HFD affected PGC1α content. HFD increased (P<0.05) PTP1b, SIRT1, and CD36 content and α2 deletion prevented the HFD‐induced increases in PTP1b and SIRT1. In HFD, α2 deletion decreased (P<0.05) CPT1 content. These data show that AMPKα2 may be more critical for the regulation of FAU and FAO under basal than IS conditions and that it affects CPT1, PTP1b, and SIRT1 content and IS SIRT1 activity with HFD.

Nonalcoholic fatty liver disease (NAFLD) is one of the main liver diseases today, and may progress to steatohepatitis, cirrhosis, and hepatocellular carcinoma. Some studies have shown the beneficial effects of aerobic exercise on reversing NAFLD. To verify whether chronic aerobic exercise improves the insulin resistance, liver inflammation, and steatohepatitis caused by a high fat diet (HF) and whether PPARα is involved in these actions. C57BL6 wild type (WT) and PPAR-α knockout (KO) mice were fed with a standard diet (SD) or HF during 12 weeks; the HF mice were trained on a treadmill during the last 8 weeks. Serum glucose and insulin tolerances, serum levels of aspartate aminotransferase, hepatic content of triacylglycerol, cytokines, gene expression, and protein expression were evaluated in all animals. Chronic exposure to HF diet increased triacylglycerol accumulation in the liver, leading to NAFLD, increased aminotransferase in the serum, increased peripheral insulin resistance, and higher adiposity index. Exercise reduced all these parameters in both animal genotypes. The liver lipid accumulation was not associated with inflammation; trained KO mice, however, presented a huge inflammatory response that was probably caused by a decrease in PPAR-γ expression. We conclude that exercise improved the damage caused by a HF independently of PPARα, apparently by a peripheral fatty acid oxidation in the skeletal muscle. We also found that the absence of PPARα together with exercise leads to a decrease in PPAR-γ and a huge inflammatory response. J. Cell. Physiol. 232: 1008-1019, 2017. © 2016 Wiley Periodicals, Inc.

Characterization of a selective inverse agonist for estrogen related receptor α as a potential agent for breast cancer

Metabolic syndrome is a lifestyle-related disease caused by high nutrient condition and lack of exercise. The insulin resistance due to obesity has attracted attention as an underlying mechanism of metabolic syndrome. Insulin resistance refers to reduced insulin sensitivity in insulin target tissues. In this case, in order to maintain normal blood glucose levels, a compensatory large amount of insulin is released, leading to the occurrence of hyperinsulinemia. Taurine is widely distributed in animal tissues. Although it is not involved in protein synthesis, taurine plays an important role in maintaining the body's physiological function. In this experiment, insulin resistance model was induced by high fat and high sugar diet. Two percent taurine was added in drinking water to explore the mechanism of taurine in insulin resistance and to provide theoretical basis for using taurine to improve insulin resistance. The result showed that high-fat and high-sugar diet could decrease insulin sensitivity, and taurine could improve it by oral glucose tolerance test. Moreover, serum TG, TC were higher, while HDL-C in rats fed with high sugar and high fat diet was lower than normal rats, the changes of which can be significantly relieved by 2% taurine administration. mRNA and protein expressions of IRS1, and GLUT4 which were significantly changed by high sugar and high fat diet can also be regulated by 2% taurine. The results indicated that taurine can improve insulin sensitivity through remediating lipid metabolism disorder and regulating the expressions of IRS and GLUT4.

This study provides insight into therapy for lung cancer, establishing p-Cresol (p-C) as an inhibitor of Pyruvate Dehydrogenase Kinase 3 (PDK3). PDK3 is critical in cancer metabolism by regulating the pyruvate dehydrogenase complex, shifting cellular energy production towards glycolysis, and promoting tumor growth and survival under hypoxic conditions. In this study, we have used computational and experimental approaches. Molecular docking reveals that p-C occupies PDK3’s binding pocket and forms interactions with key residues, especially Asp 287. Molecular dynamic simulation (MD) studies showed that p-C induced minimum alterations in PDK3, suggesting the structural stability of the PDK3-p-C complex. A fluorescence-based binding study demonstrated the binding of p-C to PDK3 with a binding constant of 3.8 × 108 M−1, indicating excellent binding affinity. Cell-based enzyme assay revealed significant inhibition of PDK3 by p-C, establishing it as a PDK3 inhibitor. Moreover, cellular assays also demonstrated significant inhibition of PDK3 activity and tumor progression. This study provides a promising therapeutic avenue for improving lung cancer treatment outcomes by targeting PDK3. Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-25246-3.

Introduction: Despite the success of anti-PD1/PDL1 therapies, only a small fraction of patients benefit from these checkpoint inhibitors (CPIs). Novel approaches to improve outcomes for patients who are resistant to current CPIs are needed. PVRIG is expressed on CD4+ and CD8+ T cells, NKT and NK cells. PVRIG binds with high affinity with its ligand PVRL2, which is expressed on tumor cells and some myeloid cells. The PVRIG-PVRL2 axis exerts an inhibitory effect on the cytotoxic activity of lymphocytes. Bispecific antibodies that exhibit dual blockade of PD1 and PVRIG provide a promising strategy to enhance anti-tumor immune response. Methods: An anti-PD1 mAb was identified from PD1 KO mice immunized with PD1-ECD-Fc and screened by our proprietary H3 (High-throughput, High-content and High-efficiency) platform. An anti-PVRIG mAb was identified from rats immunized with recombinant PVRIG-ECD-Fc and screened by the H3 platform. Both anti-PD1 and anti-PVRIG antibodies were humanized, and the anti-PD1 scFv was fused to the N-terminus of the heavy chain of the anti-PD1 antibody via a flexible linker. The binding activities and affinities were evaluated by ELISA, FACS and SPR, and the ligand blocking activities were measured by ELISA and FACS. Cell-based reporter assays were used to evaluate the functions of the anti-PD1 and anti-PVRIG mAbs alone and the bispecific antibody. In addition, the activity of the bispecific antibody to reverse PD1 and PVRIG mediated suppression of CMV pp65495-503 antigen specific CD8+ T-cell cytotoxicity was evaluated. Results: BSI-507, an anti-PD1xanti-PVRIG bispecific antibody demonstrated comparable activity to the parental anti-PD1 antibody regarding PD1 binding and PD1/PDL1 blocking. It also exhibited comparable activity to the parental anti-PVRIG antibody in PVRIG binding and PVRIG/PVRL2 blocking. Based on cell-based reporter assays, BSI-507 was able to reverse either PD1 or PVRIG mediated T-cell suppression and exhibited comparable potency to the parental antibodies. BSI-507 was also able to show enhanced reversal of both PD1 and PVRIG mediated T-cell suppression, much better than anti-PD1 or anti-PVRIG alone. In addition, BSI-507 showed the ability to reverse PD1 and PVRIG mediated suppression of CMV pp65495-503 antigen specific CD8+ T-cell cytotoxicity, stronger than either the anti-PD1 or anti-PVRIG monoclonal antibody. Summary: BSI-507 is a first-in-class anti-PD1xanti-PVRIG bispecific antibody for dual blockade of PD-1 and PVRIG pathways to enhance reversal of T cell inhibition. BSI-507 demonstrates favorable biophysical and functional characteristics, supporting the initiation of development activities including manufacturing and IND-enabling studies. Citation Format: Zeyu Peng, Xiaodong F. Liu, Hongyan Li, Wenwen Dai, Jinyu Liu, Xiaoyao Hao, Shukai Xia, Qun Lv, Hugh M. Davis, Mingjiu Chen, Mark Z. Ma. BSI-507, a first-in-class bispecific antibody targeting PD1 and PVRIG for cancer immunotherapy. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6367.

We investigated in rats fed a purified diet for 2 and 4 months whether wine drinking was associated with the rebound effect on thrombin-induced platelet aggregation observed after alcohol withdrawal. With 6% ethanol drinking or its equivalent in red or white wine, platelet aggregation was reduced similarly by 70% when the animals drank the alcoholic beverages up to the venipuncture. Depriving the rats of alcoholic beverages for 18 hours was associated with an increase in the platelet response of 124% in those receiving 6% ethanol, of 46% with white wine but a decrease of 59% in those with red wine. The protective effect of red wine on platelets could be reproduced by tannins (procyanidins) extracted from grape seeds or red wine and added to 6% ethanol, but not by glycerol or wine without alcohol. That was related to inhibition of the alcohol-induced lipid peroxidation as shown by the lowering of conjugated dienes, lipid peroxides, and the increase in vitamin E in plasma. Owing to tannins, the platelets of rats drinking red wine did not exhibit the rebound effect observed hours after alcohol drinking, eventually associated with sudden death and stroke in humans.

BackgroundThe role of vitamin D in obesity and diabetes is debated. Obese and/or diabetic patients have elevated levels of free fatty acids, increased susceptibility to gastrointestinal symptoms and are suggested to have altered vitamin D balance. The enteric nervous system is pivotal in regulating gastrointestinal activity and high fat diet (HFD) has been shown to cause loss of enteric neurons in ileum and colon. This study investigates the effect of vitamin D on HFD- and palmitic acid-induced enteric neuronal loss in vivo and in vitro.MethodsMice were fed either a normal diet (ND) or HFD supplemented with varying levels of vitamin D (from 0x to 20x normal vitamin D level) for 19 weeks. Ileum and colon were analyzed for neuronal numbers and remodeling. Primary cultures of myenteric neurons from mouse small intestine were treated with palmitic acid (4x10-4M) and/or 1α,25-hydroxy-vitamin D3 (VD, 10-11- 10-7M) with or without modulators of lipid metabolism and VD pathways. Cultures were analyzed by immunocyto- and histochemical methods.ResultsVitamin D supplementation had no effect on enteric neuronal survival in the ND group. HFD caused substantial loss of myenteric neurons in ileum and colon. Vitamin D supplementation between 0-2x normal had no effect on HFD-induced neuronal loss. Supplementation with 20x normal, prevented the HFD-induced neuronal loss. In vitro supplementation of VD prevented the palmitic acid-induced neuronal loss. The VD receptor (VDR) was not identified in enteric neurons. Enteric glia expressed the alternative VD receptor, protein disulphide isomerase family A member 3 (PDIA3), but PDIA3 was not found to mediate the VD response in vitro. Inhibition of peroxisome proliferator-activated receptor gamma (PPARγ) and immune neutralization of isocitrate lyase prevented the VD mediated neuroprotection to palmitic acid exposure.ConclusionsResults show that VD protect enteric neurons against HFD and palmitic acid induced neuronal loss. The mechanism behind is suggested to be through activation of PPARγ leading to improved neuronal peroxisome function and metabolism of neuronal lipid intermediates.

Farnesoid X receptors (FXR) are bile acid receptors that play roles in lipid, glucose, and energy homeostasis. Synthetic FXR-specific agonists have been developed for treating nonalcoholic fatty liver disease (NAFLD) patients. However, the detailed mechanism remains unclear. To investigate the effects of FXR on NAFLD and the possible mechanism, FXR-null mice were fed either a normal or a high-fat diet. The FXR-null mice developed hepatomegaly, steatosis, accumulation of lipid droplets in liver cells, glucose metabolism disorder, and elevated serum lipid levels. Transcriptomic results showed increased expression of key lipid synthesis and glucose metabolism-related proteins. We focused on pyruvate dehydrogenase kinase 4 (PDK4), a key enzyme involved in the regulation of glucose and fatty acid (FA) metabolism and homeostasis. Subsequently, we confirmed an increase in PDK4 expression in FXR knockout cells. Moreover, inhibition of PDK4 expression alleviated lipid accumulation in hepatocytes caused by FXR deficiency in vivo and in vitro. Our results identify FXR as a nuclear transcription factor that regulates glucose and lipid metabolism balance through PDK4, providing further insights into the mechanism of FXR agonists in the treatment of metabolic diseases.

The nicotinamide adenine dinucleotide (NAD(+))-dependent deacetylase SIRT1 is a major metabolic regulator activated by energy stresses such as fasting or calorie restriction. SIRT1 activation during fasting not only relies on the increase in the NAD(+)/NADH ratio caused by energy deprivation but also involves an upregulation of SIRT1 mRNA and protein levels in various metabolic tissues. We demonstrate that SIRT1 expression is controlled systemically by the activation of the cyclic AMP response-element-binding protein upon low nutrient availability. Conversely, in the absence of energetic stress, the carbohydrate response-element-binding protein represses the expression of SIRT1. Altogether, these results demonstrate that SIRT1 expression is tightly controlled at the transcriptional level by nutrient availability and further underscore that SIRT1 is a crucial metabolic checkpoint connecting the energetic status with transcriptional programmes.

Metabolic dysfunction–associated steatohepatitis (MASH) is increasing worldwide along with the obesity epidemic. However, there are limited treatments. Fibroblast growth factor (FGF)19 and its mouse ortholog FGF15, act as hormones to repress bile acid synthesis and increase energy expenditure. Activation of peroxisome proliferator–activated receptor (PPAR)α increases fatty acid oxidation in hepatocytes. However, a combined role of FGF19/15 with activation of PPARα in the treatment of MASH is unknown. Wild-type and Fgf15 transgenic (Fgf15 Tg) mice were fed a high-fat diet (HFD) to induce MASH, then a PPARα agonist was subsequently administered to a subcohort of HFD groups to study the synergistic effect of Fgf15 overexpression and PPARα activation. HFD feeding diminished glucose tolerance and increased liver fat accumulation in both wild-type and Fgf15 Tg mice. However, Fgf15 Tg mice demonstrated resistance to weight gain, displayed improved glucose tolerance, and attenuated liver steatosis. Fgf15 overexpression alone reduced liver injury and the expression of genes involved in inflammation and fibrosis. The activation of PPARα, both individually and in conjunction with FGF15 overexpression, led to weight loss and reduced liver steatosis. However, the combined approach with PPARα activation and FGF15 overexpression resulted in an increase in liver injury and upregulation of gene expression associated with inflammation and fibrosis. In summary, Overexpression of FGF15 alone, with or without a combined activation of PPARα, effectively reduces hepatic steatosis. However, the combined treatment leads to increased oxidative stress and ductular reactions, indicating a complex interplay in the pathogenesis of MASH.Significance StatementFibroblast growth factor (FGF)15 overexpression and peroxisome proliferator–activated receptor (PPAR)α activation ameliorates high-fat diet–induced hepatic steatosis. Combined PPARα activation and FGF15 overexpression exacerbated high-fat diet–induced liver injury and inflammation. Overexpression of FGF15 alone or combination with PPARα activation induced antioxidant response and ductular reactions.

ABSTRACTBackgroundA significant increase in mitochondrial fatty acid oxidation (FAO) is now increasingly recognized as one of the metabolic alterations in diabetic cardiomyopathy (DCM). However, the molecular mechanisms underlying mitochondrial FAO impairment in DCM remain to be fully elucidated.MethodsA type 2 diabetes (T2D) mouse model was established by a combination of high‐fat diet (HFD) and streptozotocin (STZ) injection. Neonatal rat cardiomyocytes were treated with high glucose (HG) and palmitic acid (HP) to simulate diabetic cardiac injury. Gain‐ and loss‐of‐function approaches and RNA sequencing were utilized to investigate the role and mechanism of 2,4‐dienoyl‐CoA reductase 1 (Decr1) in DCM.ResultsBy integrating the genomic data available in the Gene Expression Omnibus (GEO) with DCM rodents, we found that the transcriptional level of Decr1 was consistently upregulated in DCM (+255% for diabetic heart, p < 0.0001; +281% for diabetic cells, p < 0.0001). Cardiomyocytes‐specific knockdown of Decr1 preserved cardiac function (+41% for EF, p < 0.0001; +24% for FS, p = 0.0052), inhibited cardiac hypertrophy (−34%, p < 0.0001), fibrosis (−69%, p < 0.0001), apoptosis (−56%, p < 0.0001) and oxidative damage (−59%, p < 0.0001) in DCM mice, while cardiomyocytes‐specific overexpression of Decr1 aggravated DCM (−28% for EF, p = 0.0347; −17% for FS, p = 0.0014). Deletion of Decr1 prevented high glucose/palmitate (HG/HP)‐induced hypertrophy (−22%, p = 0.0006), mitochondrial dysfunction and apoptosis (−74%, p < 0.0001) in cultured cardiomyocytes. Furthermore, RNA sequencing and functional analysis showed that Decr1 interacted with and upregulated pyruvate dehydrogenase kinase 4 (PDK4) in injured cardiomyocytes, and overexpression of PDK4 eliminated the benefits of Decr1 downregulation in DCM (−20% for EF, p = 0.0071; −28% for FS, p = 0.0022). Mechanistically, PDK4 acted as a kinase that induced phosphorylation and mitochondrial translocation of HDAC3. In the mitochondria, HDAC3 mediated the deacetylation of dehydrogenase trifunctional multienzyme complex α subunit (HADHA), contributing to excessive mitochondrial FAO and subsequent cardiac injury. From a screening of 256 natural products, we identified Atranorin and Kurarinone as potential inhibitors of Decr1, both demonstrating protective effects against DCM (Atranorin, +21% for EF, p = 0.0134; +24% for FS, p = 0.0006; Kurarinone, +20% for EF, p = 0.0183; +27% for FS, p = 0.0001).ConclusionsOur study delineates a molecular mechanism by which Decr1 potentiated higher mitochondrial lipid oxidation and cardiac damage by enhancing HADHA deacetylation through the PDK4/HDAC3 signalling pathway.

Failing heart loses its metabolic flexibility, relying increasingly on glucose as its preferential substrate and decreasing fatty acid oxidation (FAO). Peroxisome proliferator-activated receptor α (PPAR-α) is a key regulator of this substrate shift. However, its role during heart failure is complex and remains unclear. Recent studies reported that heart failure develops in the heart of myosin heavy chain-PPAR-α transgenic mice in a manner similar to that of diabetic cardiomyopathy, whereas cardiac dysfunction is enhanced in PPAR-α knockout mice in response to chronic pressure overload. We created a pressure-overload heart failure model in mice through transverse aortic constriction (TAC) and activated PPAR-α during heart failure using an inducible transgenic model. After 8 wk of TAC, left ventricular (LV) function had decreased with the reduction of PPAR-α expression in wild-type mice. We examined the effect of PPAR-α induction during heart failure using the Tet-Off system. Eight weeks after the TAC operation, LV construction was preserved significantly by PPAR-α induction with an increase in PPAR-α-targeted genes related to fatty acid metabolism. The increase of expression of fibrosis-related genes was significantly attenuated by PPAR-α induction. Metabolic rates measured by isolated heart perfusions showed a reduction in FAO and glucose oxidation in TAC hearts, but the rate of FAO preserved significantly owing to the induction of PPAR-α. Myocardial high-energy phosphates were significantly preserved by PPAR-α induction. These results suggest that PPAR-α activation during pressure-overloaded heart failure improved myocardial function and energetics. Thus activating PPAR-α and modulation of FAO could be a promising therapeutic strategy for heart failure.NEW & NOTEWORTHY The present study demonstrates the role of PPAR-α activation in the early stage of heart failure using an inducible transgenic mouse model. Induction of PPAR-α preserved heart function, and myocardial energetics. Activating PPAR-α and modulation of fatty acid oxidation could be a promising therapeutic strategy for heart failure.

Ethanol in alcoholic beverages is a known carcinogen, but its association with aggressive prostate cancer (APC) is uncertain. Recent studies have shown a modest increase in risk of APC associated with heavy alcohol intake while association for beverage types remain inconsistent. Using a case-control design and self-administered questionnaire, we examined the association between APC (high grade and/or advanced stage) and frequency and quantity of alcohol intake 2 years prior to enrolment. Furthermore, we delineated the relationships for beverage-specific intakes of beer, red wine, white wine and spirits. The study included 1282 APC cases and 951 controls. Beer intake frequency of ⩾5 days per week was associated with increased risk compared with no beer intake (odds ratio=1.66, 95% confidence interval: 1.12-2.48) whereas wine was protective at all frequencies of consumption compared with those with no wine intake. For every 10 g per week ethanol intake from beer increase, the odds of advanced PC rose by 3% (OR=1.03, 95% CI: 1.02-1.05). No such increased risk was observed for red or white wine while a marginal dose-response relationship was found for spirits (OR=1.03, 95% CI: 0.99-1.07). Heavy beer and possibly spirits consumption is associated with increased risk while no dose-response relationship was found for red or white wine. Wine drinkers at all frequencies have a decreased risk of APC compared with those who did not drink wine.