GPR30 Research Articles

G-protein-coupled receptor 41 in cardiomyocytes: Effect of butyrate on intracellular Ca2+ and sarcomere shortening.

G-protein-coupled receptor 41 (GPR41) is a Gαi-coupled receptor activated by short-chain fatty acids (SCFAs). Here, we tested that GPR41 is also expressed in cardiomyocytes and exerts a direct negative inotropic effect when activated by SCFA butyrate. Primary cardiomyocytes were isolated from wild-type (WT) and GPR41 knockout (GPR41-/-) adult mice and intracellular Ca2+ concentration and cell shortening were measured using the IonOptix system. RNA localization (RNAScope), quantitative real-time polymerase chain reaction (qRT-PCR), immunofluorescence staining, and western blot were used to examine the expression of GPR41 in adult primary cardiomyocytes of WT and GPR41-/- mice. The effect of butyrate on shortening and intracellular Ca2+ transient via GPR41 was also tested in cardiomyocytes. We demonstrated for the first time the presence of GPR41s on cardiomyocytes. Butyrate dose-dependently decreased cell shortening and the amplitude of intracellular Ca2+ transients in cardiomyocytes from WT but not GPR41-/- mice. In WT cardiomyocytes, butyrate decreased caffeine-mediated amplitudes of intracellular Ca2+ transients from the sarcoplasmic reticulum (SR). Moreover, the inhibitory effects of butyrate on cell shortening and intracellular Ca2+ were pertussis toxin (PTX)-sensitive. Finally, butyrate decreased the activity of sarcoendoplasmic reticulum Ca2+-ATPase (SERCA) and cellular 3'-5'-cyclic adenosine monophosphate (cAMP) content. In conclusion, GPR41 is expressed on cardiomyocytes. Butyrate, a known GPR41 agonist, reduces cardiomyocyte shortening and intracellular Ca2+ transient via decreasing Ca2+ content in the SR by inhibiting SERCA activity in a PTX-dependent manner. These findings establish that GPR41 is directly activated by SCFAs to decrease contraction and intracellular Ca2+ transient, highlighting the potential inhibitory role of GPR41 in cardiomyocytes.

Attenuation of Hypertension and protection of vascular inflammation in hyperaldosteronism: GPER1 as potential therapeutic candidate when MR antagonist is less satisfying?

Hyperaldosteronism is an endocrine disorder leading to persistent and severe hypertension. G protein-coupled estrogen receptor 1(GPER1) is regarded as a potential receptor of aldosterone (ALDO). This study aimed to investigate the effects of GPER1 on aldosterone (ALDO)-induced hypertension and inflammation in mice. GPER1-knockout (KO) and wild-type (WT) C57BL/6j mice were divided into control (CON, normal saline treatment), ALDO (subcutaneous injections of 600 g/kg/d ALDO), and ALDO + eplerenone (EPL) (subcutaneous injections of 600 g/kg/d ALDO and 100 mg/kg/d EPL) groups (n = 5 per group). Fourteen days after drug administration, the heart rate and tail blood pressure of the mice in the different groups were measured. S100A8 and IL-1β protein expression in arterial tissues were detected by western blotting, NLRP3 expression was assessed using immunofluorescence, and CD68 expression was investigated using immunohistochemistry. GPER1 deficiency alleviated ALDO-induced diastolic blood pressure (P< 0.05). In addition, the protein expression levels of IL-1β, S100A8, and CD68 showed significant decreases in the arterial tissues of GPER1-KO mice after combination treatment with ALDO and EPL (all P < 0.05). We discovered attenuation of hypertension and vascular inflammation of GPER1 KO mice only on the basis of mineralocorticoid receptor (MR) blocking. Collectively, our study indicates that GPER1 might become a therapeutic target of hyperaldosteronism in controlling the residual risk of cardiovascular disease when MR antagonist alone is not satisfying.

Chronic metabolic effects of novel gut-oriented small-molecule GPR119 agonists in diet-induced obese mice

The pharmacological activation of G-protein coupled receptor-119 (GPR119) modulates glucose, energy, and hepatic lipid homeostasis in type-2 diabetes (T2D). We developed synthetic small-molecule GPR119 agonists targeting gastrointestinal receptors. This study investigates the chronic metabolic effects of lead candidates, ps297 and ps318, individually and in combination with sitagliptin, a dipeptidyl peptidase-IV (DPP-IV) inhibitor, in high-fat diet (HFD)-induced obese (DIO) mice. In a 10-week dose-escalation protocol, DIO mice were orally treated with the investigational agents alone (10–90 mg/kg/day) and in combination with sitagliptin (20 mg/kg/day). Weekly body weight, food intake, and random blood glucose levels were monitored during the treatment phase. Post-treatment, an intraperitoneal glucose tolerance test (ipGTT), estimation of plasma biomarkers and haematological assessment were conducted. The treatment’s effect on hepatic steatosis was studied by estimating liver biomarkers and histological examinations. Ten-week sitagliptin combination therapy with the investigational entities restored incretins, insulin, and other metabolic hormonal secretions, accompanied by improved glucose homeostasis and retarded weight gain. Interestingly, monotherapy with investigational agents improved liver health by reducing liver weight, liver enzymes, and inflammation. Hepatic effects were further enhanced by co-administration of sitagliptin, evident by amelioration in hepatic steatosis endpoints such as liver weight, plasma liver enzyme concentrations, hepatic triglycerides (TG), total cholesterol (CHO), hydroxyproline content, and cytokine levels. Histopathological investigations confirmed regression in hepatic steatosis in the combination groups. These findings demonstrate the therapeutic potential of novel gut-oriented GPR119 agonists in combination with a DPP-IV inhibitor to ameliorate metabolic dysfunction-associated steatohepatitis (MASH), warranting further mechanistic investigations.

Abstract 4117657: Targeting GPR39 for Hypoxia-induced Pulmonary Hypertension in Mice

Background: Primary pulmonary arterial hypertension (PAH) is a disease affecting young subjects. It has very poor prognosis and optimal treatment is not available. 15-hydroxyeicosatetraenoic acid (15-HETE), a potent vasoconstrictor, has been implicated in the pathogenesis of PAH. Elevated levels of 15-HETE have been shown to be associated with worse prognosis in patients with PAH. Oral ingestion of 15-HETE leads to development of PAH in rodents. We recently showed that 15-HETE is the endogenous agonist for the G-protein coupled receptor 39 (GPR39) present in vascular smooth muscle cells. Hypothesis: We, therefore, hypothesized that global deletion of GPR39 (knock-out [KO] mice) would protect from PAH by removing the receptor through which 15-HETE causes vasoconstriction. Methods: Accordingly, 13 wild-type (WT) and 16 KO mice were placed in a hypoxia chamber (10% O 2 ). Litter-mate controls (7 WT and 13 KO) were subjected to normoxia (room air, 21% O 2 ). At the end of 4 weeks heart rate as well as aortic and right ventricular (RV) pressures were measured (latter using micromanometer-tipped catheter), and the animals were then euthanized for measurement of RV wall thickness and RV size from which RV wall stress was calculated. Results: Heart rate and systolic blood pressure were not different between the 4 groups . WT hypoxic animals developed PAH with peak RV systolic pressures (RVSP) being significantly higher than normoxic WT and hypoxic WT and hypoxic KO mice. (Figure 1) Similar results were noted for RV end-diastolic pressure (Figure 2) and RV wall stress (Figure 3). Conclusions: By deleting GPR39, the target for 15-HETE, we were able to prevent hypoxia induced PAH and RV dysfunction. Pharmacological inhibition of GPR39 may open new frontiers in the treatment of PAH.

Cardioprotection and neurobehavioral impact of swimming training in ovariectomized rats.

Cardiovascular (CV) disease is the major cause of mortality. Estrogens (E) exert multiple CV and neuroprotective effects. During menopause, CV and cognitive pathologies increase dramatically. At present, it is known that E exert many of their beneficial effects through the G protein-coupled estrogen receptor (GPER). Exercise reduces the risk of developing CV diseases. Sodium/proton exchanger (NHE-1) is overexpressed in ovariectomized (OVX) rats, probably due to the increase in reactive oxidative species (ROS). Insulin-like growth factor 1 (IGF-1), the main humoral mediator of exercise, inhibits the NHE-1. We aim to explore the subcellular mechanisms involved in the heart and brain impact of physiological exercise in OVX rats. We speculate that physical training, via IGF-1, prevents the increase in ROS, improving heart and brain physiological functions during menopause. Exercise diminished cardiac ROS production and increased catalase (CAT) activity in OVX rats. In concordance, IGF-1 treatment reduces brain ROS, surely contributing to the improvement in brain behavior. Moreover, the aerobic routine was able to prevent, and IGF-1 therapy to revert, NHE-1 hyperactivity in OVX rats. Finally, our results confirm the proposed signaling pathway as IGF-1/PI3K-AKT/NO. Surprisingly, GPER inhibitor (G36) was able to abolish the IGF-1 effect, suggesting that directly or indirectly GPER is part of the IGF-1 pathway. We propose that IGF-1 is the main responsible for the protective effect of aerobic training both in the heart and brain in OVX rats. Moreover, we showed that not only it is possible to prevent but also to revert the menopause-induced NHE-1 hyperactivity by exercise/IGF-1 cascade.

Estrogen Regulates Ca2+ to Promote Mitochondrial Function Through G-Protein-Coupled Estrogen Receptors During Oocyte Maturation.

Estrogen is a steroid hormone that plays a key role in regulating many physiological processes, such as follicle activation and development and oocyte maturation in mammals. Ca2+ is crucial in oogenesis, oocyte maturation, ovulation, and fertilization. However, the mechanism by which estrogen regulates Ca2+ during oocyte maturation in mice has not been reported. This study revealed that Ca2+ levels in oocytes significantly increase during the 4-12 h period in vitro. Oocytes treated with 0.1 µM estrogen and 1 µM G1, a G-protein-coupled estrogen receptor (GPER) agonist, showed significantly increased Ca2+ levels, while treatment with 1 µM G15, an antagonist of GPER, significantly decreased Ca2+ levels. Notably, estrogen regulates Ca2+ in oocytes through the GPER pathway and promotes the expression of the Ca2+-producing protein EPAC1. In addition, estrogen alleviates the inhibitory effect of the Ca2+ chelator BAPTA-AM during oocyte maturation by promoting Ca2+ production. Furthermore, estrogen can promote the expression of the mitochondrial generation-associated protein SIRT1 through the GPER pathway, alleviate mitochondrial oxidative damage caused by BAPTA-AM, and restore the mitochondrial membrane potential level. Collectively, this study demonstrates that estrogen can regulate Ca2+ through the GPER-EPAC1 pathway and promote the expression of SIRT1, which promotes oocyte mitochondrial function during oocyte maturation.

Effect of Diosgenin in Suppressing Viability and Promoting Apoptosis of Human Prostate Cancer Cells: An Interplay with the G Protein-Coupled Oestrogen Receptor?

Diosgenin is a phytosteroid sapogenin with reported antitumoral activity. Despite the evidence indicating a lower incidence of prostate cancer (PCa) associated with a higher consumption of phytosteroids and the beneficial role of these compounds, only a few studies have investigated the effects of diosgenin in PCa, and its mechanisms of action remain to be disclosed. The present study investigated the effect of diosgenin in modulating PCa cell fate and glycolytic metabolism and explored its potential interplay with G protein-coupled oestrogen receptor (GPER). Non-neoplastic (PNT1A) and neoplastic (LNCaP, DU145, and PC3) human prostate cell lines were stimulated with diosgenin in the presence or absence of the GPER agonist G1 and upon GPER knockdown. Diosgenin decreased the cell viability, as indicated by the MTT assay results, which also demonstrated that castrate-resistant PCa cells were the most sensitive to treatment (PC3 > DU145 > LNCaP > PNT1A; IC50 values of 14.02, 23.21, 56.12, and 66.10 µM, respectively). Apoptosis was enhanced in diosgenin-treated cells, based on the increased caspase-3-like activity, underpinned by the altered expression of apoptosis regulators evaluated by Western blot analysis, which indicated the activation of the extrinsic pathway. Exposure to diosgenin also altered glucose metabolism. Overall, the effects of diosgenin were potentiated in the presence of G1. Moreover, diosgenin treatment augmented GPER expression, and the knockdown of the GPER gene suppressed the proapoptotic effects of diosgenin in PC3 cells. Our results support the antitumorigenic role of diosgenin and its interest in PCa therapy, alone or in combination with G1, mainly targeting the more aggressive stages of the disease.

Targeting GPR39 in structure-based drug discovery reduces Ang II-induced hypertension.

The endothelium-dependent vascular injury, a primary pathological feature of angiotensin II (Ang II)-induced hypertension. This study aimed to explore the role and underlying mechanisms of G protein-coupled receptor 39 (GPR39) in the pathogenesis of Ang II-induced hypertension. For in vivo studies, GPR39 knockout (KO) mice (C57BL/6 J, male) were generated and administered Ang II for 4 weeks. GPR39 expression was upregulated in the aorta of hypertensive patients and mice. The ablation of GPR39 mitigated vascular fibrosis, augmented endothelium-dependent vasodilation, and inhibited endothelial inflammation, oxidative stress, and apoptosis in mice. Additionally, GPR39 KO decreased NOD-like receptor protein 3 (Nlrp3) gene expression in Ang II-stimulated endothelial cells. Notably, Nlrp3 activation counteracted the therapeutic benefits of GPR39 KO. We identified the potential ligand of GPR39 using structure-based high throughput virtual screening (HTVS) and validated its antihypertensive function in vitro and in vivo. The small molecule ligand Z1780628919 of GPR39 can also reduce Ang II-induced hypertension and improve vascular function. GPR39 KO and the small molecule ligand Z1780628919 potentially downregulates Nlrp3, thereby mitigating vascular fibrosis, endothelial inflammation, oxidative stress, and apoptosis. This effect contributes to the alleviation of Ang II-induced hypertension and the rectification of vascular dysfunctions. These findings suggest new avenues for therapeutic intervention.

GPR55 antagonist CID16020046 suppresses DNCB-induced atopic dermatitis-like symptoms by suppressing Th1/Th2/Th17 populations in mice

G protein-coupled receptor 55 (GPR55) is a lipid-sensing receptor that plays a role as an immune mediator and is primarily upregulated during immune cell activation. There is a lack of knowledge about the role of GPR55 in allergic inflammatory diseases such as atopic dermatitis. The purpose of this study was to investigate the role of GPR55 through the use of its antagonist, CID16020046, in an atopic dermatitis mouse model. It was found that BALB/c mice develop lesions similar to those associated with atopic dermatitis following sensitization and repeated exposure to 1-chloro-2,4-dinitrobenzene (DNCB). It was found that CID16020046 (1 mg/kg, i. p.) alleviated the atopic dermatitis-like symptoms as well as immune dysregulation caused by DNCB. Based on histopathological analysis, CID16020046 reduced ear thickening and mast cell counts in the dermis. CID16020046 decreased DNCB-induced increases in serum IgE levels, as measured using enzyme-linked immunosorbent assays. A significant reduction in lymph node hypertrophy was also observed with CID16020046 as well as significant reductions in CD4+ T helper 1 (Th1), Th2, and Th17 cells in the lymph nodes. As a result of the administration of CID16020046, cytokines of Th1 (IFN-γ), Th2 (IL-4 and IL-13), and Th17 (IL-17 A) types were also reduced in the skin and lymph nodes. In conclusion, blocking GPR55 alleviates DNCB-induced atopic dermatitis-like symptoms, suggesting that GPR55 is a potential therapeutic target for allergic inflammatory diseases via immunoregulation.

Copy Number Variation and Selection Signal: Exploring the Domestication History and Phenotype Differences Between Duroc and the Chinese Native Ningxiang Pigs.

The Ningxiang pig, one of the well-known Chinese native pig breeds, has the advantages of tender meat, high intramuscular fat (IMF) content, and roughage tolerance, compared to the commercial lean pig breeds. The genetic basis for complex traits in Ningxiang pigs has been previously studied through other genetic markers, such as Single Nucleotide Polymorphism (SNP), while the characteristics of copy number variation (CNV) and the selection signal have not been investigated yet. In this study, GGP 50 k genotyping data of 2242 Ningxiang pigs (NX) and 1137 Duroc pigs (Duroc) were involved in CNV atlas construction and selection signals identification. Annotations of genes and quantitative trait locus (QTLs) were performed on the target candidate regions, as follows: (1) 162 CNVs were detected in Ningxiang pigs, while 326 CNVs were detected in Duroc pigs, and there are 21 copy number variation regions (CNVRs) shared between them; (2) The CNVRs of Duroc are more abundant, with 192 CNVRs, accounting for 1.61% of the entire genome, while those of Ningxiang pigs only have 98 CNVRs, accounting for 0.49%; (3) The QTLs annotated on CNVs and selected regions of Ningxiang pigs were mainly associated with meat quality and fertility. In contrast, the Duroc QTLs' notes relate primarily to the carcass and immunity, and explain why they have a higher slaughter rate and immunity; (4) There is a presence of high-frequency acquired CNVs, specifically in Ningxiang pigs, with 24 genes significantly enriched in the sensory receptor-related pathway in this region; (5) Based on the CNVs atlas, candidate genes such as 3 inositol 1,4,5-triphosphate receptor, type 3 (ITPR3), forkhead box protein K2 (FOXK2), G-protein coupled estrogen receptor 1 (GPER1), Glyceraldehyde 3-phosphate dehydrogenase (GAPDH), triosephosphate isomerase 1 (TPI1), and other candidate genes related to fat deposition and differentiation were screened. In general, this study improved our knowledge about copy number variation and selection signal information of Ningxiang pigs, which can not only further explain the genetic differences between Chinese native and Western commercial pig breeds, but also provide new materials for the analysis of the genetic basis of complex traits.

Intricate roles of estrogen and estrogen receptors in digestive system cancers: a systematic review.

Gender disparities are evident across different types of digestive system cancers, which are typically characterized by a lower incidence and mortality rate in females compared to males. This finding suggests a potential protective role of female steroid hormones, particularly estrogen, in the development of these cancers. Estrogen is a well-known sex hormone that not only regulates the reproductive system but also exerts diverse effects on non-reproductive organs mediated through interactions with estrogen receptors (ERs), including the classic (ERα and ERβ) and non-traditional ERs [G protein-coupled estrogen receptor (GPER)]. Recent advances have contributed to our comprehension of the mechanisms underlying ERs in digestive system cancers. In this comprehensive review we summarize the current understanding of the intricate roles played by estrogen and ERs in the major types of digestive system cancers, including hepatocellular, pancreatic, esophageal, gastric, and colorectal carcinoma. Furthermore, we discuss the potential molecular mechanisms underlying ERα, ERβ, and GPER effects, and propose perspectives on innovative therapies and preventive measures targeting the pathways regulated by estrogen and ERs. The roles of estrogen and ERs in digestive system cancers are complicated and depend on the cell type and tissue involved. Additionally, deciphering the intricate roles of estrogen, ERs, and the associated signaling pathways may guide the discovery of novel and tailored therapeutic and preventive strategies for digestive system cancers, eventually improving the care and clinical outcomes for the substantial number of individuals worldwide affected by these malignancies.

Structure of G protein-coupled receptor GPR1 bound to full-length chemerin adipokine reveals a chemokine-like reverse binding mode.

Chemerin is an adipokine with chemotactic activity to a subset of leukocytes. Chemerin binds to 3 G protein-coupled receptors, including chemokine-like receptor 1 (CMKLR1), G protein-coupled receptor 1 (GPR1), and C-C chemokine receptor-like 2 (CCRL2). Here, we report that GPR1 is capable of Gi signaling when stimulated with full-length chemerin or its C-terminal nonapeptide (C9, YFPGQFAFS). We present high-resolution cryo-EM structures of Gi-coupled GPR1 bound to full-length chemerin and to the C9 peptide, respectively. C9 insertion into the transmembrane (TM) binding pocket is both necessary and sufficient for GPR1 signaling, whereas the full-length chemerin uses its bulky N-terminal core for interaction with a β-strand located at the N-terminus of GPR1. This interaction involves multiple β-strands of full-length chemerin, forming a β-sheet that serves as a "lid" for the TM binding pocket and is energetically expensive to remove as indicated by molecular dynamics simulations with free energy landscape analysis. Combining results from functional assays, our structural model explains why C9 is an activating peptide at GPR1 and how the full-length chemerin uses a "two-site" model for enhanced interaction with GPR1.

Structural Basis for Chemerin Recognition and Signaling Through Its Receptors.

Chemerin is a chemotactic adipokine that participates in a multitude of physiological processes, including adipogenesis, leukocyte chemotaxis, and neuroinflammation. Chemerin exerts biological functions through binding to one or more of its G protein-coupled receptors (GPCRs), namely chemokine-like receptor 1 (CMKLR1), G protein-coupled receptor 1 (GPR1), and CC-motif receptor-like 2 (CCRL2). Of these receptors, CMKLR1 and GPR1 have been confirmed as signaling receptors of chemerin, whereas CCRL2 serves as a chemerin-binding protein without transmembrane signaling. High-resolution structures of two chemerin receptors are now available thanks to recent advancements in structure biology. This review focuses on the structural perspectives of the chemerin receptors with an emphasis on the structure-activity correlation, including key components of the two receptors for ligand recognition and conformational changes induced by chemerin and its derivative peptides for G protein activation. There are also comparisons between the two chemerin receptors and selected GPCRs with peptide ligands for better appreciation of the shared and distinct features of the chemerin receptors in ligand recognition and transmembrane signaling, and in the evolution of this subclass of GPCRs.

High glucose combined with lipopolysaccharide stimulation inhibits cell proliferation and migration of human HaCaT keratinocytes by impacting redox homeostasis and activating the polyol pathway.

High glucose level and chronic inflammation are characteristic features of diabetic cutaneous wounds. Keratinocytes make up the epidermis and play an important role in skin repair. However, metabolomic changes of keratinocytes in chronic diabetic ulcers have not been fully studied. This study used high levels of glucose combined with lipopolysaccharide to treat human HaCaT keratinocytes. Untargeted metabolomic combined with colorimetric assays were used to explore the changes of keratinocyte metabolites and related metabolic pathways caused by high glucose and lipopolysaccharide. Results demonstrated that high glucose combined with lipopolysaccharide treatment increased intracellular reactive oxygen species and impaired proliferation and migration of keratinocytes. Untargeted metabolomics analysis identified a total of 273 differential metabolites. Redox metabolism associated metabolites were largely altered. Reduced nicotinamide adenine dinucleotide, gamma-glutamylcysteine, superoxide dismutase activity and SOD2 gene expression were significantly upregulated while nicotinamide adenine dinucleotide, glutathione, glutathione peroxidase, several types of lysophosphatidylcholine, lysophosphatidylinositol, and GPR55 gene expression were downregulated. Alterations of glutathione and nicotinamide adenine dinucleotide were verified by colorimetric assays. For the first time, high glucose and LPS were observed to boost the levels of fructose, aldose reductase and sorbitol dehydrogenase of the polyol pathway in HaCaT cells. Further treatment of HaCaT with fructose leading to inhibition of cell proliferation and migration. Our data suggest high glucose combined with lipopolysaccharide significantly altered redox homeostasis associated metabolites and activate the polyol pathway in keratinocytes to impact cell proliferation and migration, providing new strategies for the treatment of chronic diabetic ulcers.

Effects of moxibustion in improving synovitis in adjuvant arthritis rats by regulating synovial GPR43 and peripheral blood Th17/Treg balance

To observe the effects of moxibustion on G protein-coupled receptor 43 (GPR43) and helper T cell 17 (Th17)/regulatory T cell (Treg) balance in rats with adjuvant arthritis (AA), so as to investigate the partial mechanism of moxibustion therapy on rheumatoid arthritis (RA). A total of 24 Wistar rats were randomly divided into a normal group, a model group and a moxibustion group, with 8 rats in each group. The AA rat model was replicated using wind, cold and moisture environmental factors + Freund's complete adjuvant (CFA) injection method. In the moxibustion group, moxibustion was performed on bilateral "Zusanli" (ST36) and "Shenshu" (BL23) for 20 min/time, once daily, for 21 d. The changes of joint swelling degree (JSD) and arthritis index (AI) were observed in each group of rats. Transmission electron microscopy and HE staining were used to examine changes in the cellular structure of the ankle joint synovial tissue in each group. Western blot analysis was employed to detect the expression levels of GPR43 in the synovial tissue of the ankle joints. Flow cytometry was used to measure the percentages of Treg and Th17 in peripheral blood. ELISA was used to determine the contents of interleukin-10 (IL-10) and transforming growth factor-β 1 (TGF-β1) in serum. Compared with the normal group, the JSD and AI in the model group increased before and after treatment (P<0.01), with significant synovial pathological and ultrastruct ural injury observed. Additionally, compared with the normal group, the expression of GPR43 in the synovial tissue decreased (P<0.01), the Treg percentage in peripheral blood decreased (P<0.01) and the Th17 percentage increased (P<0.01), serum IL-10 and TGF-β1 contents decreased in the model group (P<0.01). Compared with the model group, the moxibustion group exhibited a significant reduction in JSD and AI after treatment (P<0.01), the degree of pathological and ultrastruct ural damage in the synovium decreased, the expression of GPR43 in the synovial tissue increased (P<0.05), the Treg percentage in peripheral blood increased (P<0.01) and the Th17 percentage decreased (P<0.01), serum IL-10 and TGF-β1 contents increased (P<0.01). The relative expression of GPR43 in synovial tissue was positively correlated with the percentage of Treg in peripheral blood (r=0.967, P<0.01). Moxibustion can significantly improve the inflammatory response in the synovial membrane of AA rats. The mechanism may be related to moxibustion restoring the Th17/Treg balance through regulating GPR43.

MNAM enhances Blautia abundance and modulates Th17/Treg balance to alleviate diabetes in T2DM mice

This study investigated the therapeutic effects of N1-Methylnicotinamide (MNAM), a metabolic derivative, on T2DM mice induced by a high-fat diet and streptozotocin (STZ), focusing on its impact on the gut microbiome and immune modulation. MNAM significantly reduced hyperglycemia and enhanced insulin secretion, effects that were dependent on the presence of gut microbiota. It also mitigated STZ-induced weight loss and improved islet cell morphology, reducing islet cell mortality and increasing insulin (INS) levels. Flow cytometry analysis showed a decrease in T helper 17 cells (Th17) and an increase in Treg cells after MNAM treatment, corresponding to the upregulation of Treg markers [interleukin (IL)-10, forkhead box P3 (FOXP3)] and downregulation of Th17 markers [IL17A, RAR-related orphan receptor gamma (RORγt)]. Additionally, MNAM raised anti-inflammatory IL-10 levels while reducing pro-inflammatory cytokines [IL-17α, tumor necrosis factor (TNF-α), IL-6]. Microbiome analysis revealed decreased diversity and increased Blautia abundance post-MNAM administration. Treatment with Blautia not only reversed diabetes indicators but also modulated the Th17/Treg balance and reduced inflammation, with its metabolite sodium acetate mimicking these effects through the G protein-coupled receptor 43 (GPR43) pathway. These findings suggest that MNAM’s mitigation of diabetes operates through modulation of the gut microbiota and immune regulation, highlighting Blautia and its metabolite as potential therapeutic agents and providing a theoretical foundation for novel treatment strategies in T2DM.

Omega-3 polyunsaturated fatty acids alleviate hyperuricemic nephropathy by inhibiting renal pyroptosis through GPR120

Hyperuricemic nephropathy (HN) is characterized by increased serum uric acid levels that incite renal inflammation. While omega-3 polyunsaturated fatty acids (PUFAs) are known for their anti-inflammatory properties, their impact on HN remains unclear. This study explored the effects of omega-3 PUFAs, specifically docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), on HN. Using a mouse model induced by adenine and potassium oxonate, we treated HN mice with DHA, EPA, or both for four weeks. The results showed that omega-3 PUFAs significantly reduced serum uric acid levels and improved kidney function, with DHA, EPA, and their combination showing similar efficacy. Transcriptome sequencing and further analysis revealed that these fatty acids alleviate renal pyroptosis by reducing key markers such as NOD-like receptor pyrin containing 3 (NLRP3), cleaved gasdermin-D, caspase-1, and interleukin-1β. To further investigate the underlying mechanism, we focused on G-protein coupled receptor 120 (GPR120), a receptor activated by DHA. The use of a GPR120 antagonist (AH7614) partially blocked DHA’s effects, while the agonist (TUG891) mimicked its anti-pyroptotic actions. Co-immunoprecipitation assays showed that DHA activates GPR120, leading to its internalization and interaction with β-arrestin2, ultimately inhibiting NLRP3 inflammasome formation and reducing inflammation. Overall, omega-3 PUFAs, particularly through GPR120 activation, appear to protect against renal inflammation in HN by modulating the NLRP3/caspase-1/GSDMD pathway.

G-protein–coupled estrogen receptor 30 regulation of signaling downstream of protein kinase Cε mediates sex dimorphism in hyaluronan-induced antihyperalgesia

Abstract High molecular weight hyaluronan (HMWH) inhibits hyperalgesia induced by diverse pronociceptive inflammatory mediators and their second messengers, in rats of both sexes. However, the hyperalgesia induced by ligands at 3 pattern recognition receptors, lipopolysaccharide (a toll-like receptor 4 agonist), lipoteichoic acid (a toll-like receptor 2/6 agonist), and nigericin (a NOD-like receptor family, pyrin domain containing 3 activator), and oxaliplatin and paclitaxel chemotherapy–induced peripheral neuropathy are only attenuated in males. After gonadectomy or intrathecal administration of an antisense to G-protein–coupled estrogen receptor 30 (GPER) mRNA, HMWH produces antihyperalgesia in females. In nociceptors cultured from rats that had been treated with oxaliplatin, HMWH reverses nociceptor sensitization from male and GPER antisense–treated female, but not from gonad intact females. G-protein–coupled estrogen receptor–dependent sex dimorphism for HMWH-induced antihyperalgesia was also observed for the prolongation of prostaglandin E2 (PGE2)-induced hyperalgesia in primed nociceptors. While in primed rats, HMWH inhibits early, protein kinase A-dependent hyperalgesia, 30 minutes post PGE2 injection, in both sexes; measured 4 hours post-PGE2, HMWH inhibits the protein kinase Cε (PKCε)-dependent prolongation of PGE2 hyperalgesia only in males and GPER antisense–treated females. In females, hyperalgesia induced by PKCε agonist, ψεRACK, in control but not in primed nociceptors, was inhibited by HMWH. Inhibitors of 2 GPER second messengers, extracellular-regulated kinase 1/2 and nonreceptor tyrosine kinase, also unmasked HMWH antihyperalgesia in females with oxaliplatin chemotherapy–induced peripheral neuropathy, a condition in which nociceptors are primed as well as sensitized. Our results support GPER-dependent sex dimorphism in HMWH-induced antihyperalgesia for pain induced by pattern recognition receptor agonists, and chronic inflammatory and neuropathic pain, mediated by changes in signaling downstream of PKCε in primed nociceptors.

GPR30 Agonist G1 Mitigates Sepsis-Induced Cardiac Dysfunction by Inhibiting ACE2/c-FOS-Mediated Necroptosis in Female Mice.

Sepsis is a severe inflammatory syndrome with high mortality and morbidity. Sepsis-induced myocardial dysfunction (SIMD) is a common cause of death in sepsis. The female sex is less susceptible to sepsis-related organ dysfunction, although the underlying mechanism of this sex difference remains unclear. This study explored the role of estrogen receptor G protein-coupled estrogen receptor 30 (GPR30) in septic cardiac dysfunction. Results from the present study indicated that GPR30 activation by the G1 agonist protected female mouse hearts against SIMD exposed to lipopolysaccharides. However, this beneficial effect was absent in female ACE2-knockout mice, as demonstrated by poorer cardiac contractility, myocardial injury, and necroptosis. We also demonstrated that the Stat6 transcription factor induced ace2 transcription by enhancing its promoter activity under GPR30 activation in septic hearts. The adenovirus-mediated inhibition of ACE2 targeting c-FOS expression reversed the deterioration, restored cardiac function, and improved survival in female ACE2-knockout mice. These results demonstrate the essential role of GPR30/STAT6/ACE2/c-FOS-mediated necroptosis in G1-mediated protection and provide novel insight into the pathogenesis of sepsis-related organ damage.

A computational and machine learning approach to identify GPR40-targeting agonists for neurodegenerative disease treatment.

The G protein-coupled receptor 40 (GPR40) is known to exert a significant influence on neurogenesis and neurodevelopment within the central nervous system of both humans and rodents. Research findings indicate that the activation of GPR40 by an agonist has been observed to promote the proliferation and viability of hypothalamus cells in the human body. The objective of the present study is to discover new agonist compounds for the GPR40 protein through the utilization of machine learning and pharmacophore-based screening techniques, in conjunction with other computational methodologies such as docking, molecular dynamics simulations, free energy calculations, and investigations of the free energy landscape. In the course of our investigation, we successfully identified five unreported agonist compounds that exhibit robust docking score, displayed stability in ligand RMSD and consistent hydrogen bonding with the receptor in the MD trajectories. Free energy calculations were observed to be higher than control molecule. The measured binding affinities of compounds namely 1, 3, 4, 6 and 10 were -13.9, -13.5, -13.4, -12.9, and -12.1 Kcal/mol, respectively. The identified molecular agonist that has been found can be assessed in terms of its therapeutic efficacy in the treatment of neurological diseases.