TRIM31 Deficiency Is Associated with Impaired Glucose Metabolism and Disrupted Gut Microbiota in Mice

Trim31 deficiency exacerbates airway inflammation in asthma by enhancing the activation of the NLRP3 inflammasome

Tripartite motif (Trim) 31 is important for numerous inflammatory diseases. However, whether Trim31 regulates airway inflammation in asthma remains undetermined. The present work explored the role of Trim31 in airway inflammation in asthmatic mice established by ovalbumin (OVA) stimulation. Trim31 expression was markedly downregulated in the lungs of asthmatic mice. Compared with wild-type (WT) mice, Trim31-/- mice showed more severe pathological changes accompanied by increased inflammatory cell infiltration after OVA induction. House dust mite (HDM) stimulation evoked airway epithelial cell injury and inflammation, which were exacerbated by Trim31 silencing or attenuated by Trim31 overexpression. Further examination revealed that Trim31 deficiency exacerbated the activation of the NLRP3 inflammasome in OVA-induced asthmatic mice and HDM-stimulated airway epithelial cells. The inhibition of NLRP3 markedly diminished the Trim31 silencing-mediated enhancement of HDM-induced injury and inflammation in airway epithelial cells. In conclusion, this work demonstrates that Trim31 acts as a crucial mediator of airway inflammation in asthma. Trim31 deficiency may contribute to the progression of asthma by increasing NLRP3 inflammasome activation, suggesting that Trim31 is a potential therapeutic target for asthma.

E3 ubiquitin ligase TRIM31: A potential therapeutic target

Ubiquitination is a key mechanism for post-translational protein modification, affecting protein localization, metabolism, degradation and various cellular physiological processes. Dysregulation of ubiquitination is associated with the pathogenesis of various diseases, such as tumors and cardiovascular diseases, making it a primary area of interest in biochemical research and drug development endeavors. E3 ubiquitin ligases play a pivotal role in modulating the ubiquitination of substrate proteins through their unique recognition functions. TRIM31, a member of the TRIM family of E3 ubiquitin ligases, is aberrantly expressed in different pathophysiological conditions. The biological function of TRIM31 is associated with the occurrence and development of diverse diseases. TRIM31 has been demonstrated to inhibit inflammation by promoting ubiquitin-proteasome-mediated degradation of the sensing protein NLRP3 in the inflammasome. TRIM31 mediates ubiquitination of MAVS, inducing the formation of prion-like aggregates, and triggering innate antiviral immune responses. TRIM31 is also implicated in tumor pathophysiology through its ability to promote ubiquitination of the tumor suppressor protein p53. These findings indicate that TRIM31 is a potential therapeutic target, and subsequent in-depth research of TRIM31 is anticipated to provide information on its clinical application in therapy.

Sunset Yellow dye effects on gut microbiota, intestinal integrity, and the induction of inflammasomopathy with pyroptotic signaling in male Wistar rats

Although concern persists regarding possible adverse effects of consumption of synthetic azo food dyes, the mechanisms of any such effects remain unclear. We have tested the hypothesis that chronic consumption of the food dye Sunset Yellow (SY) perturbs the composition of the gut microbiota and alters gut integrity. Male rats were administered SY orally for 12 weeks. Analysis of fecal samples before and after dye administration demonstrated SY-induced microbiome dysbiosis. SY treatment reduced the abundance of beneficial taxa such as Treponema 2, Anaerobiospirillum, Helicobacter, Rikenellaceae RC9 gut group, and Prevotellaceae UCG-003, while increasing the abundance of the potentially pathogenic microorganisms Prevotella 2 and Oribacterium. Dysbiosis disrupted gut integrity, altering the jejunal adherens junction complex E-cadherin/β-catenin and decreasing Trefoil Factor (TFF)-3. SY administration elevated LPS serum levels, activated the inflammatory inflammasome cascade TLR4/NLRP3/ASC/cleaved-activated caspase-1 to mature IL-1β and IL-18, and activated caspase-11 and gasdermin-N, indicating pyroptosis and increased intestinal permeability. The possibility that consumption of SY by humans could have effects similar to those that we have observed in rats should be examined.

Role of the tripartite motif-containing (TRIM) family of proteins in insulin resistance and related disorders

Emerging evidence suggests that the ubiquitin-mediated degradation of insulin-signalling-related proteins may be involved in the development of insulin resistance and its related disorders. Tripartite motif-containing (TRIM) proteins, a superfamily belonging to the E3 ubiquitin ligases, are capable of controlling protein levels and function by ubiquitination, which is essential for the modulation of insulin sensitivity. Recent research has indicated that some of these TRIMs act as key regulatory factors of metabolic disorders such as type 2 diabetes mellitus, obesity, nonalcoholic fatty liver disease, and atherosclerosis. This review provides a comprehensive overview of the latest evidence linking TRIMs to the regulation of insulin resistance and its related disorders, their roles in regulating multiple signalling pathways or cellular processes, such as insulin signalling pathways, peroxisome proliferator-activated receptor signalling pathways, glucose and lipid metabolism, the inflammatory response, and cell cycle control, as well as recent advances in the development of TRIM-targeted drugs.

Tripartite motif-containing protein 31 confers protection against nonalcoholic steatohepatitis by deactivating mitogen-activated protein kinase kinase kinase 7

BACKGROUND AIMS

As a global health threat, NASH has been confirmed to be a chronic progressive liver disease that is strongly associated with obesity. However, no approved drugs or efficient therapeutic strategies are valid, mainly because its complicated pathological processes is underestimated.

APPROACH RESULTS

We identified the RING-type E3 ubiquitin transferase-tripartite motif-containing protein 31 (TRIM31), a member of the E3 ubiquitin ligases family, as an efficient endogenous inhibitor of transforming growth factor-beta-activated kinase 1 (mitogen-activated protein kinase kinase kinase 7; MAP3K7), and we further confirmed that TRIM31 is an MAP3K7-interacting protein and promotes MAP3K7 degradation by enhancing ubiquitination of K48 linkage in hepatocytes. Hepatocyte-specific Trim31 deletion blocks hepatic metabolism homeostasis, concomitant with glucose metabolic syndrome, lipid accumulation, up-regulated inflammation, and dramatically facilitates NASH progression. Inversely, transgenic overexpression, lentivirus, or adeno-associated virus-mediated Trim31 gene therapy restrain NASH in three dietary mice models. Mechanistically, in response to metabolic insults, TRIM31 interacts with MAP3K7 and conjugates K48-linked ubiquitination chains to promote MAP3K7 degradation, thus blocking MAP3K7 abundance and its downstream signaling cascade activation in hepatocytes.

CONCLUSIONS

TRIM31 may serve as a promising therapeutic target for NASH treatment and associated metabolic disorders.

NLRP3: A Promising Therapeutic Target for Inflammatory Bowel Disease

Inflammatory bowel disease (IBD), which includes Crohn's disease and ulcerative colitis, is an intestinal disease with complicated pathological mechanisms. The incidence of IBD has been increasing in recent years, which has a significant negative impact on the lives of patients. Therefore, it is particularly important to find new therapeutic targets and innovative drugs for the development of IBD. Recent studies have revealed that NLRP3 inflammatory vesicles can play an important role in maintaining intestinal homeostasis and sustaining the intestinal immune response in IBD. On the one hand, aberrant activation of NLRP3 inflammatory vesicles may cause excessive immune response by converting caspase-1, proIL-18, and proIL-1β to their active forms and releasing pro-inflammatory cytokines to stimulate the development and progression of IBD, and we can improve IBD by targeting blockade of NLRP3 activation. On the other hand, NLRP3 may also play an enter protective role by maintaining the homeostasis of the intestinal immune system. In this paper, we reviewed the activation mechanism of NLRP3 inflammasome, and the effects of NLRP3 inflammasome activation on IBD are discussed from two different perspectives: pathology and protection. At the same time, we listed the effects of direct inhibitors, indirect inhibitors, and natural inhibitors of NLRP3 inflammasome on IBD in combination with cutting-edge advances and clinical practice results, providing new targets and new ideas for the clinical treatment of IBD.

Cecum microbiome and metabolism characteristics of Silky Fowl and White Leghorn chicken in late laying stages

Cecal microflora plays a key role in the production performance and immune function of chickens. White Leghorn (WL) is a well-known commercial layer line chicken with high egg production rate. In contrast, Silky Fowl (SF), a Chinese native chicken variety, has a low egg production rate, but good immune performance. This study analyzed the composition of cecal microbiota, metabolism, and gene expression in intestinal tissue of these varieties and the correlations among them. Significant differences were observed in the cecal microbes: Bacteroides was significantly enriched in WL, whereas Veillonellaceae and Parabacteroides were significantly enriched in SF. Carbohydrate biosynthesis and metabolism pathways were significantly upregulated in WL cecum, which might provide more energy to the host, leading to persistently high levels of egg production. The higher Parabacteroides abundance in SF increased volicitin content, enhanced α-linolenic acid metabolism, and significantly negatively correlated with metabolites of propanoate metabolism and carbohydrate metabolism. Genes related to lipid metabolism, immunity, and melanogenesis were significantly upregulated in the SF cecum, regulating lipid metabolism, and participating in the immune response, while genes related to glucose metabolism and bile acid metabolism were expressed at higher levels in WL, benefiting energy support. This study provided a mechanism for intestinal microorganisms and metabolic pathways to regulate chicken egg-laying performance and immunity.

RING-finger E3 ligases regulatory network in PI3K/AKT-mediated glucose metabolism

The phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathway plays an essential role in glucose metabolism, promoting glycolysis and resisting gluconeogenesis. PI3K/AKT signaling can directly alter glucose metabolism by phosphorylating several metabolic enzymes or regulators of nutrient transport. It can indirectly promote sustained aerobic glycolysis by increasing glucose transporters and glycolytic enzymes, which are mediated by downstream transcription factors. E3 ubiquitin ligase RING-finger proteins are mediators of protein post-translational modifications and include the cullin-RING ligase complexes, the tumor necrosis factor receptor-associated family, the tripartite motif family and etc. Some members of the RING family play critical roles in regulating cell signaling and are involved in the development and progression of various metabolic diseases, such as cancer, diabetes, and dyslipidemia. And with the progression of modern research, as a negative or active regulator, the RING-finger adaptor has been found to play an indispensable role in PI3K/AKT signaling. However, no reviews have comprehensively clarified the role of RING-finger E3 ligases in PI3K/AKT-mediated glucose metabolism. Therefore, in this review, we focus on the regulation and function of RING ligases in PI3K/AKT-mediated glucose metabolism to establish new insights into the prevention and treatment of metabolic diseases.

Distribution of Vaginal and Gut Microbiome in Advanced Maternal Age

The distribution of the microbiome in women with advanced maternal age (AMA) is poorly understood. To gain insight into this, the vaginal and gut microbiota of 62 women were sampled and sequenced using the 16S rRNA technique. These women were divided into three groups, namely, the AMA (age ≥ 35 years, n = 13) group, the non-advanced maternal age (NMA) (age < 35 years, n = 38) group, and the control group (non-pregnant healthy women, age >35 years, n = 11). We found that the alpha diversity of vaginal microbiota in the AMA group significantly increased. However, the beta diversity significantly decreased in the AMA group compared with the control group. There was no significant difference in the diversity of gut microbiota among the three groups. The distributions of microbiota were significantly different among AMA, NMA, and control groups. In vaginal microbiota, the abundance of Lactobacillus was higher in the pregnant groups. Bifidobacterium was significantly enriched in the AMA group. In gut microbiota, Prevotella bivia was significantly enriched in the AMA group. Vaginal and gut microbiota in women with AMA were noticeably different from the NMA and non-pregnant women, and this phenomenon is probably related to the increased risk of complications in women with AMA.

Effect of 6-Methoxybenzoxazolinone on the Cecal Microbiota of Adult Male Brandt's Vole

The anti-microbial effects of plant secondary metabolite (PSM) 6-methoxybenzoxazolinone (6-MBOA) have been overlooked. This study investigated the effect of 6-MBOA on the cecal microbiota of adult male Brandt’s voles (Lasiopodomys brandtii), to evaluate its effect on the physiology of mammalian herbivores. The growth of voles was inhibited by 6-MBOA. A low dose of 6-MBOA enhanced the observed species, as well as the Chao1 and abundance-based coverage estimator (ACE) indices and introduced changes in the structure of cecal microbiota. The abundance of the phylum Tenericutes, classes Mollicutes and Negativicutes, order Selenomonadales, families Ruminococcaceae and Veillonellaceae, genera Quinella, Caproiciproducens, Anaerofilum, Harryflintia, and unidentified Spirochaetaceae in the cecal microbiota was enhanced upon administration of a low dose of 6-MBOA, which also inhibited glucose metabolism and protein digestion and absorption in the cecal microbiota. 6-MBOA treatment also stimulated butyrate production and dose-dependently enhanced the metabolism of xenobiotics in the cecal microbiome. Our findings indicate that 6-MBOA can affect Brandt’s voles by inducing changes in the abundance of cecal bacteria, thereby, altering the contents of short-chain fatty acids (SCFAs) and pathway intermediates, ultimately inhibiting the growth of voles. Our research suggests that 6-MBOA could potentially act as a digestion-inhibiting PSM in the interaction between mammalian herbivores and plants.

The E3 ubiquitin ligase TRIM31 plays a critical role in hypertensive nephropathy by promoting proteasomal degradation of MAP3K7 in the TGF-β1 signaling pathway

Renal fibrosis and inflammation are critical for the initiation and progression of hypertensive renal disease (HRD). However, the signaling mechanisms underlying their induction are poorly understood, and the role of tripartite motif-containing protein 31 (TRIM31), an E3 ubiquitin ligase, in HRD remains unclear. This study aimed to elucidate the role of TRIM31 in the pathogenesis of HRD, discover targets of TRIM31, and explore the underlying mechanisms. Pathological specimens of human HRD kidney were collected and an angiotensin II (AngII)-induced HRD mouse model was developed. We found that TRIM31 was markedly reduced in both human and mouse HRD renal tissues. A TRIM31^-/- mice was thus constructed and showed significantly aggravated hypertension-induced renal dysfunction, fibrosis, and inflammation, following chronic AngII infusion compared with TRIM31^+/+ mice. In contrast, overexpression of TRIM31 by injecting adeno-associated virus (AAV) 9 into C57BL/6J mice markedly ameliorated renal dysfunction, fibrotic and inflammatory response in AngII-induced HRD relative to AAV-control mice. Mechanistically, TRIM31 interacted with and catalyzed the K48-linked polyubiquitination of lysine 72 on Mitogen-activated protein kinase kinase kinase 7 (MAP3K7), followed by the proteasomal degradation of MAP3K7, which further negatively regulated TGF-β1-mediated Smad and MAPK/NF-κB signaling pathways. In conclusion, this study has demonstrated for the first time that TRIM31 serves as an important regulator in AngII-induced HRD by promoting MAP3K7 K48-linked polyubiquitination and inhibiting the TGF-β1 signaling pathway.

TRIMs: Generalists Regulating the NLRP3 Inflammasome Signaling Pathway

Inflammation is a double-edged sword. The moderate inflammatory response is a fundamental defense mechanism produced by the body's resistance to dangerous stimuli and a repair process of the body itself. Increasing studies have confirmed that the overactivation of the inflammasome is involved in the occurrence and development of inflammatory diseases. Strictly controlling the overactivation of the inflammasome and preventing excessive inflammatory response have always been the research focus on inflammatory diseases. However, the endogenous regulatory mechanism of inflammasome is not completely clear. The tripartite motif (TRIM) protein is one of the members of E3 ligases in the process of ubiquitination. The universality and importance of the functions of TRIM members are recognized, including the regulation of inflammatory response. This article will focus on research on the relationship between TRIMs and NLRP3 Inflammasome, which may help us make some references for future related research and the discovery of treatment methods.

The E3 ubiquitin-protein ligase Trim31 alleviates non-alcoholic fatty liver disease by targeting Rhbdf2 in mouse hepatocytes

Systemic metabolic syndrome significantly increases the risk of morbidity and mortality in patients with non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH). However, no effective therapeutic strategies are available, practically because our understanding of its complicated pathogenesis is poor. Here we identify the tripartite motif-containing protein 31 (Trim31) as an endogenous inhibitor of rhomboid 5 homolog 2 (Rhbdf2), and we further determine that Trim31 directly binds to Rhbdf2 and facilitates its proteasomal degradation. Hepatocyte-specific Trim31 ablation facilitates NAFLD-associated phenotypes in mice. Inversely, transgenic or ex vivo gene therapy-mediated Trim31 gain-of-function in mice with NAFLD phenotypes virtually alleviates severe deterioration and progression of steatohepatitis. The current findings suggest that Trim31 is an endogenous inhibitor of Rhbdf2 and downstream cascades in the pathogenic process of steatohepatitis and that it may serve as a feasible therapeutical target for the treatment of NAFLD/NASH and associated metabolic disorders.

Nonalcoholic steatohepatitis (NASH) is a chronic liver disease with complex disease mechanisms. Here the authors report that the E3 ubiquitin-protein ligase Trim31 mitigates development of NASH via inhibition of rhomboid 5 homolog 2 (Rhbdf2) in mice.

Gut Microbiota: An Important Player in Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) is one of the common metabolic diseases in the world. Due to the rise in morbidity and mortality, it has become a global health problem. To date, T2DM still cannot be cured, and its intervention measures mainly focus on glucose control as well as the prevention and treatment of related complications. Interestingly, the gut microbiota plays an important role in the development of metabolic diseases, especially T2DM. In this review, we introduce the characteristics of the gut microbiota in T2DM population, T2DM animal models, and diabetic complications. In addition, we describe the molecular mechanisms linking host and the gut microbiota in T2DM, including the host molecules that induce gut microbiota dysbiosis, immune and inflammatory responses, and gut microbial metabolites involved in pathogenesis. These findings suggest that we can treat T2DM and its complications by remodeling the gut microbiota through interventions such as drugs, probiotics, prebiotics, fecal microbiota transplantation (FMT) and diets.

Treatment with mixed probiotics induced, enhanced and diversified modulation of the gut microbiome of healthy rats

Previous studies demonstrated that multi-strain probitics could more strongly regulate intestinal cytokines and the mucosal barrier than the individual ingredient strains. Nevertheless, the potentially different gut microbiome modulation effects between multi-strain and single-strain probiotics treatments remain unexplored. Here, we administered three different Lactiplantibacillus plantarum strains or their mixture to healthy Wistar rats and compared the shift of gut microbiome among the treatment groups. A 4-week intervention with mixed probiotics induced more drastic and diversified gut microbiome modulation than single-strain probiotics administration (alpha diversity increased 8% and beta diversity increased 18.7%). The three single-strain probiotics treatments all converged the gut microbiota, decreasing between-individual beta diversity by 12.7% on average after the treatment, while multi-strain probiotics treatment diversified the gut microbiome and increased between-individual beta diversity by 37.2% on average. Covariation analysis of the gut microbes suggests that multi-strain probiotics could exert synergistic, modified and enhanced modulation effects on the gut microbiome based on strain-specific modulation effects of probiotics. The more heterogeneous responses to the multi-strain probiotics treatment suggest that future precision microbiome modulation should consider the potential interactions of the probiotic strains, and personalized response to probiotic formulas due to heterogenous gut microbial compositions.

The E3 ubiquitin ligase TRIM31 is involved in cerebral ischemic injury by promoting degradation of TIGAR

Tripartite motif (TRIM) 31 has been implicated in diverse biological and pathological conditions. However, whether TRIM31 plays a role in ischemic stroke progression is not clarified. Here we demonstrated that TRIM31 was significantly downregulated in the ischemic brain and the deficiency of TRIM31 alleviated brain injury induced by middle cerebral artery occlusion by reducing reactive oxygen species production and maintaining mitochondrial homeostasis. Mechanistically, we found that TRIM31 is an E3 ubiquitin ligase for TP53-induced glycolysis and apoptosis regulator (TIGAR), which confers protection against brain ischemia by increasing the pentose phosphate pathway flux and preserving mitochondria function. TRIM31 interacted with TIGAR and promoted the polyubiquitination of TIGAR, consequently facilitated its degradation in a proteasome-dependent pathway. Furthermore, TIGAR knockdown effectively abolished the protective effect of TRIM31 deficiency after cerebral ischemia. In conclusion, we identified that TRIM31 was a novel E3 ubiquitin ligase for TIGAR, played a critical role in regulating its protein level, and subsequently involved in the ischemic brain injury, suggesting TRIM31 as a potential therapeutic target for ischemic stroke.

Pathology, Risk Factors, and Oxidative Damage Related to Type 2 Diabetes-Mediated Alzheimer's Disease and the Rescuing Effects of the Potent Antioxidant Anthocyanin

The pathology and neurodegeneration in type 2 diabetes- (T2D-) mediated Alzheimer's disease (AD) have been reported in several studies. Despite the lack of information regarding the basic underlying mechanisms involved in the development of T2D-mediated AD, some common features of the two conditions have been reported, such as brain atrophy, reduced cerebral glucose metabolism, and insulin resistance. T2D phenotypes such as glucose dyshomeostasis, insulin resistance, impaired insulin signaling, and systemic inflammatory cytokines have been shown to be involved in the progression of AD pathology by increasing amyloid-beta accumulation, tau hyperphosphorylation, and overall neuroinflammation. Similarly, oxidative stress, mitochondrial dysfunction, and the generation of advanced glycation end products (AGEs) and their receptor (RAGE) as a result of chronic hyperglycemia may serve as critical links between diabetes and AD. The natural dietary polyflavonoid anthocyanin enhances insulin sensitivity, attenuates insulin resistance at the level of the target tissues, inhibits free fatty acid oxidation, and abrogates the release of peripheral inflammatory cytokines in obese (prediabetic) individuals, which are responsible for insulin resistance, systemic hyperglycemia, systemic inflammation, brain metabolism dyshomeostasis, amyloid-beta accumulation, and neuroinflammatory responses. In this review, we have shown that obesity may induce T2D-mediated AD and assessed the recent therapeutic advances, especially the use of anthocyanin, against T2D-mediated AD pathology. Taken together, the findings of current studies may help elucidate a new approach for the prevention and treatment of T2D-mediated AD by using the polyflavonoid anthocyanin.

Gut microbiota and obesity-associated osteoarthritis

Obesity is a well-known primary risk factor for osteoarthritis (OA). In recent decades, the biomechanics-based theoretical paradigm for the pathogenesis of obesity-associated OA has been gradually but fundamentally modified. This modification is a result of accumulating evidence that biological factors also contribute to the etiology of the disease. The gut microbiota is a complicated ecosystem that profoundly influences the health of the host and can be modulated by the combined effects of environmental stimuli and genetic factors. Recently, enteric dysbacteriosis has been identified as a causal factor in the initiation and propagation of obesity-associated OA in animal models. Gut microbes and their components, microbe-associated lipid metabolites, and OA interact at both systemic and local levels through mechanisms that involve interplay with the innate immune system. However, the demonstration of causality in humans will require further studies. Nonetheless, probiotics, prebiotics, dietary habits and exercise, which aid the restoration of a healthy microbial community, are potential therapeutic approaches in the treatment of obesity-associated OA.