TRIB3 Is Highly Expressed in the Adipose Tissue of Obese Patients and Is Associated With Insulin Resistance

tRNA-derived fragment tRF-30 propels diabetes-induced retinal microvascular complications by regulating STAT3 signaling

Transfer RNA-derived fragments (tRFs) represent a novel class of non-coding RNA transcripts that possess specific biological functions. However, the involvement of tRFs in retinal microvascular diseases remains poorly understood. In this study, we aimed to reveal whether modulation of tRF-30 expression could attenuate pathological retinal neovascular diseases. Our findings demonstrate a significant upregulation of tRF-30 expression levels in both in vivo models of diabetic retinopathy (DR) and in vitro endothelial sprouting models. Conversely, inhibition of tRF-30 expression suppressed the formation of abnormal neovascularization in the retina in vivo, while reducing the proliferation and migration activity of retinal vascular endothelial cells in vitro. We also found that tRF-30 modulates retinal neovascularization through the tRF-30/TRIB3/signal transducer and activated transcription 3 signaling pathway. Furthermore, we validated a significant upregulation of tRF-30 expression levels in the vitreous humor of DR patients, with high levels of both validity and specificity in diagnostic testing. Collectively, our findings highlight a pro-angiogenic role for tRF-30 in DR. Intervening in the tRF-30 signaling pathway may represent a promising prevention and treatment strategy for retinal angiogenesis.

Aberrant activation of p53-TRIB3 axis contributes to diabetic myocardial insulin resistance and sulforaphane protection

INTRODUCTION

Insulin resistance (IR) is associated with multiple pathological features. Although p53- or TRIB3-orchestrated IR is extensively studied in adipose tissue and liver, the role of p53-TRIB3 axis in myocardial IR remains unknown, and more importantly target-directed therapies of myocardial IR are missing.

OBJECTIVES

Considering the beneficial effects of sulforaphane (SFN) on cardiovascular health, it is of particular interest to explore whether SFN protects against myocardial IR with a focus on the regulatory role of p53-TRIB3 axis.

METHODS

Mouse models including cardiac specific p53-overexpressing transgenic (p53-cTg) mice and Trib3 knockout (Trib3-KO) mice, combined with primary cardiomyocytes treated with p53 activator (nutlin-3a) and inhibitor (pifithrin-α, PFT-α), or transfected with p53-shRNA and Trib3-shRNA, followed by multiple molecular biological methodologies, were used to investigate the role of p53-TRIB3 axis in SFN actions on myocardial IR.

RESULTS

Here, we report that knockdown of p53 rescued cardiac insulin-stimulated AKT phosphorylation, while up-regulation of p53 by nutlin-3a or p53-cTg mice blunted insulin sensitivity in cardiomyocytes under diabetic conditions. Diabetic attenuation of AKT-mediated cardiac insulin signaling was markedly reversed by SFN in p53-Tgfl/fl mice, but not in p53-cTg mice. Importantly, we identified TRIB3 was elevated in p53-cTg diabetic mice, and confirmed the physical interaction between p53 and TRIB3. Trib3-KO diabetic mice displayed improved insulin sensitivity in the heart. More specifically, the AMPKα-triggered CHOP phosphorylation and degradation were essential for p53 on the transcriptional regulation of Trib3.

CONCLUSION

Overall, these results indicate that inhibiting the p53-TRIB3 pathway by SFN plays an unsuspected key role in the improvement of myocardial IR, which may be a promising strategy for attenuating diabetic cardiomyopathy (DCM) in diabetic patients.

Transcriptomic Analyses Reveal the Effects of Walnut Kernel Cake on Adipose Deposition in Pigs

With the rising cost of animal feed protein, finding affordable and effective substitutes is crucial. Walnut kernel cake, a polyphenol-, fiber-, protein- and fat-rich byproduct of walnut oil extraction, has been underexplored as a potential protein replacement in pig feed. In this study, we found that feeding large Diqing Tibetan pigs walnut kernel cake promoted adipose deposition and improved pork quality during pig growth. Transcriptome analysis revealed the upregulation of genes ANGPTL8, CCNP, ETV4, and TRIB3, associated with adipose deposition. Pathway analysis highlighted enrichment in adipose deposition-related pathways, including PPAR, insulin, PI3K-Akt, Wnt, and MAPK signaling. Further analysis identified DEGs (differentially expressed genes) positively correlated with adipose-related traits, such as PER2 and PTGES. Single-cell transcriptome data pointed to the specific expression of CD248 and PTGES in adipocyte progenitor/stem cells (APSCs), pivotal for adipocyte differentiation and adipose deposition regulation. This study demonstrates walnut kernel cake's potential to substitute soybean cake in pig feed, providing high-quality protein and promoting adipose deposition. It offers insights into feed protein replacement, human functional food, fat metabolism, and related diseases, with marker genes and pathways supporting pig breeding and pork quality improvement.

TRIB3-TRIM8 complex drives NAFLD progression by regulating HNF4α stability

BACKGROUND & AIMS

Endoplasmic reticulum (ER) stress of hepatocytes plays a causative role in non-alcoholic fatty liver disease (NAFLD). Reduced expression of hepatic nuclear factor 4α (HNF4α) is a critical event in the pathogenesis of NAFLD and other liver diseases. Whether ER stress regulates HNF4α expression remains unknown. The aim of this study was to delineate the machinery of HNF4α protein degradation and explore a therapeutic strategy based on protecting HNF4α stability during NAFLD progression.

METHODS

Correlation of HNF4α and tribbles homologue 3 (TRIB3), an ER stress sensor, was evaluated in human and mouse NAFLD tissues. RNA-sequencing, mass spectrometry analysis, co-immunoprecipitation, in vivo and in vitro ubiquitination assays were used to elucidate the mechanisms of TRIB3-mediated HNF4α degradation. Molecular docking and co-immunoprecipitation analyses were performed to identify a cell-penetrating peptide that ablates the TRIB3-HNF4α interaction.

RESULTS

TRIB3 directly interacts with HNF4α and mediates ER stress-induced HNF4α degradation. TRIB3 recruits tripartite motif containing 8 (TRIM8) to form an E3 ligase complex that catalyzes K48-linked polyubiquitination of HNF4α on lysine 470. Abrogating the degradation of HNF4α attenuated the effect of TRIB3 on a diet-induced NAFLD model. Moreover, the TRIB3 gain-of-function variant p.Q84R is associated with NAFLD progression in patients, and induces lower HNF4α levels and more severe hepatic steatosis in mice. Importantly, disrupting the TRIB3-HNF4α interaction using a cell-penetrating peptide restores HNF4α levels and ameliorates NAFLD progression in mice.

CONCLUSIONS

Our findings unravel the machinery of HNF4α protein degradation and indicate that targeting TRIB3-TRIM8 E3 complex-mediated HNF4α polyubiquitination may be an ideal strategy for NAFLD therapy.

IMPACT AND IMPLICATIONS

Reduced expression of hepatic nuclear factor 4α (HNF4α) is a critical event in the pathogenesis of NAFLD and other liver diseases. However, the mechanism of HNF4α protein degradation remains unknown. Herein, we reveal that TRIB3-TRIM8 E3 ligase complex is responsible for HNF4α degradation during NAFLD. Inhibiting the TRIB3-HNF4α interaction effectively stabilized HNF4α protein levels and transcription factor activity in the liver and ameliorated TRIB3-mediated NAFLD progression. Our findings demonstrate that disturbing the TRIM8-TRIB3-HNF4α interaction may provide a novel approach to treat NAFLD and even other liver diseases by stabilizing the HNF4α protein.

Downhill running and caloric restriction attenuate insulin resistance associated skeletal muscle atrophy via the promotion of M2-like macrophages through TRIB3-AKT pathway

BACKGROUD

Downhill running has recently become a promising exercise modality for metabolic syndrome, but the effect and precise mechanism of downhill running training on insulin resistance (IR) induced skeletal muscle atrophy remains unclear. The current study aimed to explore the benefits of downhill running training accompanied by a low-fat diet on skeletal muscle atrophy in IR mice and its possible mechanisms.

METHODS

For in vivo study, high fat diet (HFD) -induced IR mice were submitted to the downhill running training or/and caloric restriction for 8 weeks. In vitro study was performed using co-cultured RAW264.7 macrophages and C2C12 myoblasts model. Glucose tolerance test (GTT), insulin tolerance test (ITT), immunofluorescence staining, Western blot analysis, hematoxylin and eosin (H&E) staining, enzyme-linked immunosorbent assay (ELISA), Cell counting kit-8 (CCK-8) assays and glucose uptake assays were employed to explore the benefits and possible mechanisms of downhill running training accompanied by a low-fat diet on IR mice.

RESULTS

Our data revealed that HFD induces IR, which leading to skeletal muscle atrophy. Downhill running accompanied by caloric restriction mitigated HFD-induced IR and improve skeletal muscle atrophy. Further study suggested that descended TRIB3 mediated the favorable impact of downhill running on IR induced skeletal muscle atrophy by suppressing M1-like macrophages and promoting M2-like macrophages. Macrophages-specific knockdown of TRIB3 exerted similar effects on the macrophage polarization and IR related myogenesis to downhill running training accompanied by caloric restriction. In contrast, macrophages-specific overexpression of TRIB3 descended phosphorylation of AKT, further activated M1-like macrophages and aggravated IR related inhibition of myogenesis.

CONCLUSIONS

This finding demonstrated the beneficial effects of downhill running training and caloric restriction on IR related skeletal muscle atrophy by promoting M2-like macrophages through TRIB3-AKT pathway.

The pseudokinase TRIB3 controls adipocyte lipid homeostasis and proliferation in vitro and in vivo

OBJECTIVE

In vivo studies in humans and mice have implicated the pseudokinase Tribbles 3 (TRIB3) in various aspects of energy metabolism. Whilst cell-based studies indicate a role for TRIB3 in adipocyte differentiation and function, it is unclear if and how these cellular functions may contribute to overall metabolic health.

METHODS

We investigated the metabolic phenotype of whole-body Trib3 knockout (Trib3KO) mice, focusing on adipocyte and adipose tissue functions. In addition, we combined lipidomics, transcriptomics, interactomics and phosphoproteomics analyses to elucidate cell-intrinsic functions of TRIB3 in pre- and mature adipocytes.

RESULTS

Trib3KO mice display increased adiposity, but their insulin sensitivity remains unaltered. Trib3KO adipocytes are smaller and display higher Proliferating Cell Nuclear Antigen (PCNA) levels, indicating potential alterations in either i) proliferation-differentiation balance, ii) impaired expansion after cell division, or iii) an altered balance between lipid storage and release, or a combination thereof. Lipidome analyses suggest TRIB3 involvement in the latter two processes, as triglyceride storage is reduced and membrane composition, which can restrain cellular expansion, is altered. Integrated interactome, phosphoproteome and transcriptome analyses support a role for TRIB3 in all three cellular processes through multiple cellular pathways, including Mitogen Activated Protein Kinase- (MAPK/ERK), Protein Kinase A (PKA)-mediated signaling and Transcription Factor 7 like 2 (TCF7L2) and Beta Catenin-mediated gene expression.

CONCLUSIONS

Our findings support TRIB3 playing multiple distinct regulatory roles in the cytoplasm, nucleus and mitochondria, ultimately controlling adipose tissue homeostasis, rather than affecting a single cellular pathway.

Study on Potential Differentially Expressed Genes in Idiopathic Pulmonary Fibrosis by Bioinformatics and Next-Generation Sequencing Data Analysis

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive lung disease with reduced quality of life and earlier mortality, but its pathogenesis and key genes are still unclear. In this investigation, bioinformatics was used to deeply analyze the pathogenesis of IPF and related key genes, so as to investigate the potential molecular pathogenesis of IPF and provide guidance for clinical treatment. Next-generation sequencing dataset GSE213001 was obtained from Gene Expression Omnibus (GEO), and the differentially expressed genes (DEGs) were identified between IPF and normal control group. The DEGs between IPF and normal control group were screened with the DESeq2 package of R language. The Gene Ontology (GO) and REACTOME pathway enrichment analyses of the DEGs were performed. Using the g:Profiler, the function and pathway enrichment analyses of DEGs were performed. Then, a protein-protein interaction (PPI) network was constructed via the Integrated Interactions Database (IID) database. Cytoscape with Network Analyzer was used to identify the hub genes. miRNet and NetworkAnalyst databaseswereused to construct the targeted microRNAs (miRNAs), transcription factors (TFs), and small drug molecules. Finally, receiver operating characteristic (ROC) curve analysis was used to validate the hub genes. A total of 958 DEGs were screened out in this study, including 479 up regulated genes and 479 down regulated genes. Most of the DEGs were significantly enriched in response to stimulus, GPCR ligand binding, microtubule-based process, and defective GALNT3 causes HFTC. In combination with the results of the PPI network, miRNA-hub gene regulatory network and TF-hub gene regulatory network, hub genes including LRRK2, BMI1, EBP, MNDA, KBTBD7, KRT15, OTX1, TEKT4, SPAG8, and EFHC2 were selected. Cyclothiazide and rotigotinethe are predicted small drug molecules for IPF treatment. Our findings will contribute to identification of potential biomarkers and novel strategies for the treatment of IPF, and provide a novel strategy for clinical therapy.

Dysregulation of Lipid Droplet Protein Expression in Adipose Tissues and Association with Metabolic Risk Factors in Adult Females with Obesity and Type 2 Diabetes

BACKGROUND

Adipocyte dysregulation of lipid droplet (LD) metabolism caused by altered expression of LD proteins contributes to obesity-related metabolic diseases.

OBJECTIVES

We aimed to investigate whether expression levels of PLIN1, CIDEA, and CIDEC were altered in adipose tissues of women with obesity and type 2 diabetes and whether their alterations were associated with metabolic risk factors.

METHODS

Normal-weight (NW; 18.5 kg/m² < BMI ≤ 25 kg/m²; n = 43), nondiabetic obese (OB; BMI > 30 kg/m²; n = 38), and diabetic obese (OB/DM; BMI > 30 kg/m², fasting glucose ≥ 126 mg/dL, HbA1c ≥ 6.5%; n = 22) women were recruited. Metabolic parameters were measured, and expressions of PLIN1, CIDEA, CIDEC, and obesity-related genes were quantified in abdominal subcutaneous (SAT) and visceral adipose tissues (VAT). Effects of proinflammatory cytokines, endoplasmic reticulum (ER) stress inducers, and metabolic improvement agents on LD protein gene expressions were investigated in human adipocytes.

RESULTS

PLIN1, CIDEA, and CIDEC expressions were lower in SAT and higher in VAT in OB subjects relative to NW subjects; however, they were suppressed in both fat depots in OB/DM subjects relative to OB (P < 0.05). Across the entire cohort, whereas VAT PLIN1 (r = 0.349) and CIDEC expressions (r = 0.282) were positively associated with BMI (P < 0.05), SAT PLIN1 (r = -0.390) and CIDEA expressions (r = -0.565) were inversely associated. After adjustment for BMI, some or all of the adipose LD protein gene expressions were negatively associated with fasting glucose (r = -0.259 or higher) and triglyceride levels (r = -0.284 or higher) and positively associated with UCP1 expression (r = 0.353 or higher) (P < 0.05). In adipocytes, LD protein gene expressions were 55-70% downregulated by increased proinflammatory cytokines and ER stress but 2-4-fold upregulated by the metabolic improvement agents exendin-4 and dapagliflozin (P < 0.05).

CONCLUSIONS

The findings suggest that reduction of adipose LD protein expression is involved in the pathogenesis of metabolic disorders in women with obesity and type 2 diabetes and that increasing LD protein expression in adipocytes could control development of metabolic disorders.

TRIB3 promoter 33 bp VNTR is associated with the risk of cerebrovascular disease in type 2 diabetic patients

Previous studies have demonstrated that TRIB3 is closely related to insulin resistance, metabolic disorders and vascular diseases. Recently, it was reported that a 33 bp variable number of tandem repeats (VNTR) located in the TRIB3 promoter could considerably alter its transcriptional activity. Nonetheless, whether the shift of TRIB3 transcriptional activity has the effect of inducing diabetic vascular complications is still unclear. Therefore, in our study, we aimed to explore the relationship between the TRIB3 33bp VNTR and diabetic vascular complications. The TRIB3 33bp VNTR polymorphisms were determined by PCR and Sanger sequencing, a total of 798 eligible Chinese patients with type 2 diabetes (T2DM) were included in our study and then evaluated with clinical data. After adjusting for age, gender, BMI, smoking history, drinking history and duration of diabetes, we found that the high number of 33 bp tandem repeats (repeats>8) was significantly associated with an increase in the risk of cerebrovascular diseases compared with the low number of 33 bp tandem repeats (repeats≤6) in patients with T2DM(OR 2.66, 95% CI 1.29–5.47, p = 0.008). The intermediate number of 33bp tandem repeats (6 < repeat≤8) was markedly associated with a decreased risk of diabetic retinopathy compared with the low number of tandem repeats (OR 0.65, 95% CI 0.46–0.91, p = 0.012). Adjusting for gender, age and BMI, there was a significant difference in DBP levels among patients with the number of different 33 bp tandem repeats (Low vs. Intermediate vs. High, 81.6 ± 12.8 vs. 79.8 ± 12.4 vs. 78.7 ± 12.6 mmHg; p = 0.045). Subgroup analysis found that TRIB3 VNTR was significantly correlated with the difference in systolic blood pressure (SBP) in T2DM patients taking ACEI/ARB drugs (Low vs. Intermediate vs. High, 146.27 ± 18.23 vs. 140.01 ± 19.91 vs. 140.77 ± 18.64 mmHg; p = 0.018). Our results indicated that TRIB3 promoter 33bp VNTR is related to vascular diseases in T2DM patients, and may serve as a new biomarker for individualized prevention and therapy of T2DM.

Gut-brain mechanisms underlying changes in disordered eating behaviour after bariatric surgery: a review

Bariatric surgery results in long-term weight loss and an improved metabolic phenotype due to changes in the gut-brain axis regulating appetite and glycaemia. Neuroendocrine alterations associated with bariatric surgery may also influence hedonic aspects of eating by inducing changes in taste preferences and central reward reactivity towards palatable food. However, the impact of bariatric surgery on disordered eating behaviours (e.g.: binge eating, loss-of-control eating, emotional eating and 'addictive eating'), which are commonly present in people with obesity are not well understood. Increasing evidence suggests gut-derived signals, such as appetitive hormones, bile acid profiles, microbiota concentrations and associated neuromodulatory metabolites, can influence pathways in the brain implicated in food intake, including brain areas involved in sensorimotor, reward-motivational, emotional-arousal and executive control components of food intake. As disordered eating prevalence is a key mediator of weight-loss success and patient well-being after bariatric surgery, understanding how changes in the gut-brain axis contribute to disordered eating incidence and severity after bariatric surgery is crucial to better improve treatment outcomes in people with obesity.

Adipose tissue LECT2 expression is associated with obesity and insulin resistance in Korean women

OBJECTIVE

Leukocyte cell-derived chemotaxin 2 (LECT2) is an obesity-upregulated hepatokine inducing skeletal muscle insulin resistance. The study's aim was to explore whether LECT2 is expressed in human adipose tissue and whether the expression is dysregulated during obesity and associated with obesity-related metabolic disorders.

METHODS

This study measured metabolic parameters, serum LECT2, and expression of LECT2 and CD209, a gene encoding a putative receptor for LECT2, in abdominal subcutaneous and visceral adipose tissues in women with obesity (with or without type 2 diabetes) and women with normal weight. The expression/secretion of LECT2 and its putative effects were assessed in human adipocytes.

RESULTS

Adipose tissue LECT2 mRNA and serum LECT2 were higher in women with obesity and were significantly correlated with parameters related to insulin resistance. LECT2 was mainly expressed by adipocytes. Both LECT2 and CD209 expression was higher in adipocytes from women with obesity. Incubating adipocytes with substances mimicking the microenvironment of obesity adipose tissue increased LECT2 expression/secretion. LECT2 treatment of adipocytes suppressed insulin-stimulated Akt phosphorylation; it reduced adiponectin (ADIPOQ) and increased leptin (LEP) expression in a CD209-dependent manner.

CONCLUSIONS

This study demonstrates that LECT2 expression in adipose tissue is high in patients with obesity and associated with insulin resistance and suggests that adipocyte-derived LECT2 may contribute to adipose tissue dysfunction.