High glucose-induced endothelial STING activation inhibits diabetic wound healing through impairment of angiogenesis.

Chronic hyperglycemia-induced impairment of angiogenesis is important in diabetic foot ulcer (DFU). Additionally, the stimulator of interferon gene (STING), which is a key protein in innate immunity, mediates palmitic acid-induced lipotoxicity in metabolic diseases through oxidative stress-induced STING activation. However, the role of STING in DFU is unknown. In this study, we established a DFU mouse model with streptozotocin (STZ) injection and found that the expression of STING was significantly increased in the vascular endothelial cells of wound tissues from diabetic patients and in the STZ-induced diabetic mouse model. We further established high glucose (HG)-induced endothelial dysfunction with rat vascular endothelial cells and found that the expression of STING was also increased by high-glucose treatment. Moreover, the STING inhibitor, C176, promoted diabetic wound healing, whereas the STING activator, DMXAA, inhibited diabetic wound healing. Consistently, STING inhibition reversed the HG-induced reduction of CD31 and vascular endothelial growth factor (VEGF), inhibited apoptosis, and promoted migration of endothelial cells. Notably, DMXAA treatment alone was sufficient to induce endothelial cell dysfunction as a high-glucose treatment. Mechanistically, STING mediated HG-induced vascular endothelial cell dysfunction by activating the interferon regulatory factor 3/nuclear factor kappa B pathway. In conclusion, our study reveals an endothelial STING activation-mediated molecular mechanism in the pathogenesis of DFU and identifies STING as a novel potential therapeutic target for DFU.

The role of oxidative stress in diabetes mellitus-induced vascular endothelial dysfunction.

Diabetes mellitus is a metabolic disease characterized by long-term hyperglycaemia, which leads to microangiopathy and macroangiopathy and ultimately increases the mortality of diabetic patients. Endothelial dysfunction, which has been recognized as a key factor in the pathogenesis of diabetic microangiopathy and macroangiopathy, is characterized by a reduction in NO bioavailability. Oxidative stress, which is the main pathogenic factor in diabetes, is one of the major triggers of endothelial dysfunction through the reduction in NO. In this review, we summarize the four sources of ROS in the diabetic vasculature and the underlying molecular mechanisms by which the pathogenic factors hyperglycaemia, hyperlipidaemia, adipokines and insulin resistance induce oxidative stress in endothelial cells in the context of diabetes. In addition, we discuss oxidative stress-targeted interventions, including hypoglycaemic drugs, antioxidants and lifestyle interventions, and their effects on diabetes-induced endothelial dysfunction. In summary, our review provides comprehensive insight into the roles of oxidative stress in diabetes-induced endothelial dysfunction.

Hyperglycemia-induced STING signaling activation leads to aortic endothelial injury in diabetes.

Hyperglycaemia-induced endothelial dysfunction is a key factor in the pathogenesis of diabetic microangiopathy and macroangiopathy. STING, which is a newly discovered regulator of innate immunity, has also been reported to play an important role in various metabolic diseases. However, the role of STING in diabetes-induced endothelial cell dysfunction is unknown. In this study, we established a diabetic macroangiopathy mouse model by streptozotocin (STZ) injection combined with high-fat diet (HFD) feeding and a glucotoxicity cell model in high glucose (HG)-treated rat aortic endothelial cells (RAECs). We found that STING expression was specifically increased in the endothelial cells of diabetic arteries, as well as in HG-treated RAECs. Moreover, genetic deletion of STING significantly ameliorated diabetes-induced endothelial cell dysfunction and apoptosis in vivo. Likewise, STING inhibition by C-176 reversed HG-induced migration dysfunction and apoptosis in RAECs, whereas STING activation by DMXAA resulted in migration dysfunction and apoptosis. Mechanistically, hyperglycaemia-induced oxidative stress promoted endothelial mitochondrial dysfunction and mtDNA release, which subsequently activated the cGAS-STING system and the cGAS-STING-dependent IRF3/NF-kB pathway, ultimately resulting in inflammation and apoptosis. In conclusion, our study identified a novel role of STING in diabetes-induced aortic endothelial cell injury and suggested that STING inhibition was a potential new therapeutic strategy for the treatment of diabetic macroangiopathy. Video Abstract.

Fecal virome transplantation: A promising strategy for the treatment of metabolic diseases.

Metabolic diseases are a group of disorders caused by metabolic abnormalities, including obesity, diabetes, non-alcoholic fatty liver disease, and more. Increasing research indicates that, beyond inherent metabolic irregularities, the onset and progression of metabolic diseases are closely linked to alterations in the gut microbiota, particularly gut bacteria. Additionally, fecal microbiota transplantation (FMT) has demonstrated effectiveness in clinically treating metabolic diseases, notably diabetes. Recent attention has also focused on the role of gut viruses in disease onset. This review first introduces the characteristics and influencing factors of gut viruses, then summarizes their potential mechanisms in disease development, highlighting their impact on gut bacteria and regulation of host immunity. We also compare FMT, fecal filtrate transplantation (FFT), washed microbiota transplantation (WMT), and fecal virome transplantation (FVT). Finally, we review the current understanding of gut viruses in metabolic diseases and the application of FVT in treating these conditions. In conclusion, FVT may provide a novel and promising treatment approach for metabolic diseases, warranting further validation through basic and clinical research.

Targeting cell death in NAFLD: mechanisms and targeted therapies.

Nonalcoholic fatty liver disease (NAFLD) is a group of chronic liver disease which ranges from simple steatosis (NAFL) to non-alcoholic steatohepatitis (NASH) and is characterized by lipid accumulation, inflammation activation, fibrosis, and cell death. To date, a number of preclinical studies or clinical trials associated with therapies targeting fatty acid metabolism, inflammatory factors and liver fibrosis are performed to develop effective drugs for NAFLD/NASH. However, few therapies are cell death signaling-targeted even though the various cell death modes are present throughout the progression of NAFLD/NASH. Here we summarize the four types of cell death including apoptosis, necroptosis, pyroptosis, and ferroptosis in the NAFLD and the underlying molecular mechanisms by which the pathogenic factors such as free fatty acid and LPS induce cell death in the pathogenesis of NAFLD. In addition, we also review the effects of cell death-targeted therapies on NAFLD. In summary, our review provides comprehensive insight into the roles of various cell death modes in the progression of NAFLD, which we hope will open new avenues for therapeutic intervention.

Based on network pharmacology and molecular docking to explore the molecular mechanism of Ginseng and Astragalus decoction against postmenopausal osteoporosis.

Traditional Chinese medicine suggests that Ginseng and Astragalus Decoction (GAD) may effectively treat postmenopausal osteoporosis (PMO). However, the exact mechanism of action for GAD remains unclear. This study aims to utilize network pharmacology and molecular docking technology to explore the potential mechanism of GAD in treating PMO. The main chemical components of GAD were identified by consulting literature and traditional Chinese medicine systems pharmacology database. GeneCards and online mendelian inheritance in man were used to identify PMO disease targets, and Cytoscape 3.8.2 software was used to construct a herb-disease-gene-target network. The intersection of drug targets and disease targets was introduced into the search tool for the retrieval of interacting genes platform to construct a protein-protein interaction network. Additionally, we further conducted gene ontology and Kyoto encyclopedia of genes and genomes enrichment analyses, followed by molecular docking between active ingredients and core protein targets. We have identified 59 potential targets related to the treatment of PMO by GAD, along with 33 effective components. Quercetin and kaempferol are the compounds with higher degree. In the protein-protein interaction network, IL6, AKT1, and IL1B are proteins with high degree. The enrichment analysis of gene ontology and KEEG revealed that biological processes involved in treating PMO with GAD mainly include response to hormones, positive regulation of phosphorylation, and regulation of protein homodimerization activity. The signal pathways primarily include Pathways in cancer, PI3K-Akt signaling pathway, and AGE-RAGE signaling pathway. Molecular docking results indicate that kaempferol and quercetin have a high affinity for IL6, AKT1, and IL1B. Our research predicts that IL6, AKT1, and IL1B are highly likely to be potential targets for treating PMO with GAD. PI3K/AKT pathway and AGE-ARGE pathway may play an important role in PMO.

Comparative transcriptomic analysis reveals the underlying molecular mechanism in high-fat diet-induced islet dysfunction.

Obesity, characterized by accumulation of adipose, is usually accompanied by hyperlipidemia and abnormal glucose metabolism, which destroys the function and structure of islet ß cells. However, the exact mechanism of islet deterioration caused by obesity has not yet been fully elucidated. Here, we fed C57BL/6 mice with a high-fat diet (HFD) for 2 (2M group) and 6 months (6M group) to construct obesity mouse models. Then, RNA-based sequencing was used to identify the molecular mechanisms in HFD-induced islet dysfunction. Compared with the control diet, a total of 262 and 428 differentially expressed genes (DEGs) were identified from islets of the 2M and 6M groups, respectively. GO and KEGG enrichment analysis revealed that the DEGs up-regulated in both the 2M and 6M groups are mainly enriched in response to endoplasmic reticulum stress and the pancreatic secretion pathway. DEGs down-regulated in both the 2M and 6M groups are mainly enriched in the neuronal cell body and protein digestion and absorption pathway. Notably, along with the HFD feeding, mRNA expression of islet cell markers was significantly down-regulated, such as Ins1, Pdx1, MafA (ß cell), Gcg, Arx (α cell), Sst (δcell), and Ppy (PP cell). In contrast, mRNA expression of acinar cell markers was remarkably up-regulated, such as Amy1, Prss2, and Pnlip. Besides, a large number of collagen genes were down-regulated, such as Col1a1, Col6a6, and Col9a2. Overall, our study provides a full-scale DEG map regarding HFD-induced islet dysfunction, which was helpful to understand the underlying molecular mechanism of islet deterioration further.

BDH1-mediated ßOHB metabolism ameliorates diabetic kidney disease by activation of NRF2-mediated antioxidative pathway.

A ketogenic diet (KD) and ß-hydroxybutyrate (ßOHB) have been widely reported as effective therapies for metabolic diseases. ß-Hydroxybutyrate dehydrogenase 1 (BDH1) is the rate-limiting enzyme in ketone metabolism. In this study, we examined the BDH1-mediated ßOHB metabolic pathway in the pathogenesis of diabetic kidney disease (DKD). We found that BDH1 is downregulated in the kidneys in DKD mouse models, patients with diabetes, and high glucose- or palmitic acid-induced human renal tubular epithelial (HK-2) cells. BDH1 overexpression or ßOHB treatment protects HK-2 cells from glucotoxicity and lipotoxicity by inhibiting reactive oxygen species overproduction. Mechanistically, BDH1-mediated ßOHB metabolism activates NRF2 by enhancing the metabolic flux of ßOHB-acetoacetate-succinate-fumarate. Moreover, in vivo studies showed that adeno-associated virus 9-mediated BDH1 renal expression successfully reverses fibrosis, inflammation, and apoptosis in the kidneys of C57 BKS db/db mice. Either ßOHB supplementation or KD feeding could elevate the renal expression of BDH1 and reverse the progression of DKD. Our results revealed a BDH1-mediated molecular mechanism in the pathogenesis of DKD and identified BDH1 as a potential therapeutic target for DKD.

Maresin 1 Alleviates Diabetic Kidney Disease via LGR6-Mediated cAMP-SOD2-ROS Pathway.

BACKGROUND: Chronic hyperglycemia-induced inflammation is recognized as the most important pathophysiological process in diabetic kidney disease (DKD). As maresin 1 (MaR1) is an extensive anti-inflammatory lipid mediator, the present study investigated the protective role of MaR1 in the pathogenesis of DKD and its clinical relevance. METHODS: Serum MaR1 concentrations were analyzed in 104 subjects with normal glucose tolerant, type 2 diabetes (T2DM), or DKD. Streptozotocin (STZ) together with high fat diet was used to induce male C57BL/6 J mice into diabetic mice which were treated with MaR1. Human renal tubule epithelial cells (HK-2 cells) were treated by high glucose for glucotoxicity cell model and transfected with LGR6 siRNA for knockdown with MaR1 added，and detected oxidative stress and inflammatory related factors. RESULTS: Serum MaR1 concentrations were significant decreased in T2DM with or without kidney disease compared with normal participant and were lowest in patients with DKD. Serum MaR1 concentrations were negatively correlated with hemoglobin A1c (HbA1c), duration of diabetes, urinary albumin to creatinine ratio (UACR), neutrophil, and neutrophil-lymphocyte ratio and were positively correlated with high-density lipoprotein-cholesterol (HDL-C) and estimated glomerular filtration rate (eGFR). In mouse model, MaR1 injection alleviated hyperglycemia, UACR and the pathological progression of DKD. Interestingly, the renal expression of LGR6 was down-regulated in DKD and high glucose treated HK-2 cells but up-regulated by MaR1 treatment. Mechanistically, MaR1 alleviated inflammation via LGR6-mediated cAMP-SOD2 antioxidant pathway in DKD mice and high glucose treated HK-2 cells. CONCLUSIONS: Our study demonstrates that decreased serum MaR1 levels were correlated with the development of DKD. MaR1 could alleviate DKD and glucotoxicity-induced inflammation via LGR6-mediated cAMP-SOD2 antioxidant pathway. Thus, our present findings identify MaR1 as a predictor and a potential therapeutic target for DKD.

Bdh1 overexpression ameliorates hepatic injury by activation of Nrf2 in a MAFLD mouse model.

In 2020, a group of experts officially suggested metabolic dysfunction associated with fatty liver disease "MAFLD" as a more appropriate overarching term than NAFLD, indicating the key role of metabolism in fatty liver disease. Bdh1, as the rate-limiting enzyme of ketone metabolism, acts as an important metabolic regulator in liver. However, the role of Bdh1 in MAFLD is unclear. In this study, we used the transgenic db/db mice as a MAFLD mouse model and observed the downregulated expression of Bdh1 in fatty liver. In addition, expression of Bdh1 was also reduced by palmitic acid (PA) treatment in LO2 cells. Bdh1 knockdown led to ROS overproduction and ROS-induced inflammation and apoptosis in LO2 cells, while Bdh1 overexpression protected LO2 cells from lipotoxicity by inhibiting ROS overproduction. Mechanistically, Bdh1-mediated ßOHB metabolism inhibits ROS overproduction by activation of Nrf2 through enhancement of metabolic flux composed of ßOHB-AcAc-succinate-fumarate. Notably, adeno-associated virus (AAV)-mediated Bdh1 overexpression successfully reversed the hepatic function indexes, fibrosis, inflammation, and apoptosis in fatty livers from db/db mice. In conclusion, our study revealed a Bdh1-mediated molecular mechanism in pathogenesis of metabolic dysfunction related liver disease and identified Bdh1 as a novel potential therapeutic target for MAFLD.

Metformin and Fibrosis: A Review of Existing Evidence and Mechanisms.

Fibrosis is a physiological response to organ injury and is characterized by the excessive deposition of connective tissue components in an organ, which results in the disruption of physiological architecture and organ remodeling, ultimately leading to organ failure and death. Fibrosis in the lung, kidney, and liver accounts for a substantial proportion of the global burden of disability and mortality. To date, there are no effective therapeutic strategies for controlling fibrosis. A class of metabolically targeted chemicals, such as adenosine monophosphate-activated protein kinase (AMPK) activators and peroxisome proliferator-activated receptor (PPAR) agonists, shows strong potential in fighting fibrosis. Metformin, which is a potent AMPK activator and is the only recommended first-line drug for the treatment of type 2 diabetes, has emerged as a promising method of fibrosis reduction or reversion. In this review, we first summarize the key experimental and clinical studies that have specifically investigated the effects of metformin on organ fibrosis. Then, we discuss the mechanisms involved in mediating the antifibrotic effects of metformin in depth.

Chronic Ethanol Consumption Induces Osteopenia via Activation of Osteoblast Necroptosis.

Chronic high-dose alcohol consumption impairs bone remodeling, reduces bone mass, and increases the risk of osteoporosis and bone fracture. However, the mechanisms underlying alcohol-induced osteoporosis are yet to be elucidated. In this study, we showed that excess intake of ethyl alcohol (EtOH) resulted in osteopenia and osteoblast necroptosis in mice that led to necrotic lesions and reduced osteogenic differentiation in bone marrow mesenchymal stem cells (BMMSCs). We found that EtOH treatment led to the activation of the RIPK1/RIPK3/MLKL signaling, resulting in increased osteoblast necroptosis and decreased osteogenic differentiation and bone formation both in vivo and in vitro. We further discovered that excessive EtOH treatment-induced osteoblast necroptosis might partly depend on reactive oxygen species (ROS) generation; concomitantly, ROS contributed to necroptosis of osteoblasts through a positive feedback loop involving RIPK1/RIPK3. In addition, blocking of the RIPK1/RIPK3/MLKL signaling by necrostatin-1 (Nec-1), a key inhibitor of RIPK1 kinase in the necroptosis pathway, or antioxidant N-acetylcysteine (NAC), an inhibitor of ROS, could decrease the activation of osteoblast necroptosis and ameliorate alcohol-induced osteopenia both in vivo and in vitro. Collectively, we demonstrated that chronic high-dose alcohol consumption induced osteopenia via osteoblast necroptosis and revealed that RIPK1 kinase may be a therapeutic target for alcohol-induced osteopenia.

Impact of Exposure to Antibiotics During Pregnancy and Infancy on Childhood Obesity: A Systematic Review and Meta-Analysis.

OBJECTIVE: This study aimed to investigate whether antibiotic exposure during pregnancy and infancy was associated with childhood overweight or obesity. METHODS: PubMed, Embase, and Cochrane Library databases were searched from the inception date to April 18, 2019, to identify observational studies that investigated the association between antibiotic exposure during pregnancy and infancy and childhood overweight or obesity. After study selection and data extraction, the meta-analysis was conducted using Stata software version 12.0 (StataCorp LP, College Station, Texas). The evaluation of the methodological quality was carried out by AMSTAR 2 (Bruyère Research Institute, Ottawa, Ontario, Canada). RESULTS: A total of 23 observational studies involving 1,253,035 participants were included. The meta-analysis showed that prenatal exposure to antibiotics was not significantly associated with childhood overweight or obesity, whereas an increased risk of overweight or obesity was seen in subgroup analysis of the second trimester (risk ratio = 1.13; 95% CI: 1.06-1.22; P = 0.001). In contrast, antibiotic exposure during infancy could increase the risk of childhood overweight or obesity (risk ratio = 1.14; 95% CI: 1.06-1.23; P = 0.001). CONCLUSIONS: This meta-analysis found that antibiotic exposure during the second trimester and infancy could increase the risk of childhood overweight or obesity.

Wild-type menin is rapidly degraded via the ubiquitin-proteasome pathway in a rat insulinoma cell line.

Menin is encoded by multiple endocrine neoplasia type 1 (MEN1) gene, the germ line mutations of which are the main cause of pancreatic neuroendocrine tumors (PNETs). To date, a large number of frameshift, nonsense and missense mutations of MEN1 have been identified to be responsible for part of MEN1-defficient PNETs patients due to truncation or rapid degradation of menin protein. However, the stability of the wild-type (WT) menin in PNETs is totally unknown. In the present study, we observed ubiquitination of WT menin in 293T cells by transfection of ectopic WT menin and HA-ubiquitin. As expected, either endogenous or ectopic WT menin is stable in 293T cells, whereas in INS-1 cells, a rat insulinoma cell line derived from PNETs, either endogenous or ectopic WT menin is rapidly degraded through ubiquitin-proteasome pathway. Furthermore, the degradation of WT menin is more rapid in the presence of serum. Our findings suggest that in part of PNETs patients with WT MEN1, a ubiquitin-proteasome system targeting menin is untimely activated.