Skeletal Muscle TRIB3 Mediates Glucose Toxicity in Diabetes and High- Fat Diet-Induced Insulin Resistance

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.

Melatonin Inhibiting Neuronal Cells Ferroptosis Through Lipid Metabolic Reprogramming

This study aims to identify the underlying mechanism by which melatonin protects neurons. Firstly, the inhibitory effect of melatonin on ferroptosis was verified by treating HT22 cells with melatonin, Erastin, and Ferrostatin-1. Secondly, transcriptomic and metabolomic analyses were performed. Melatonin-related hub genes were identified by differential gene expression analysis, and lipid metabolism-related critical signaling pathways and biological processes (BPs) were determined by gene set enrichment analysis (GSEA). Finally, the expression of hub genes was verified by quantitative real-time PCR (qRT-PCR) or Western Blot (WB), and the involvement of Tribble 3 (Trib3) in the regulation of lipid metabolism and ferroptosis by melatonin was confirmed by Cell Counting Kit 8 (CCK-8) assay, ROS analysis, and WB. Assay results showed that melatonin significantly increased Gpx4 activity, decreased ROS generation, and inhibited ferroptosis in HT22 cells. The hub gene Trib3 was obtained by transcriptomic analysis, and its expression was upregulated with Erastin treatment. Lipid metabolomic analysis suggested that the regulation of lipid metabolism by melatonin was associated with glycerophospholipids. In vitro experiments showed that Trib3 was regulated by the upstream factor Atf4, and the protein levels of Trib3 and Atf4 were significantly increased after Erastin treatment. However, melatonin can reduce the protein levels of Trib3 and Atf4, increase the survival rate of HT-22 cells and the activity of GPX4, and reduce the ROS content. Melatonin inhibits neuronal ferroptosis by affecting the Atf4/Trib3 axis via the modulation of lipid metabolism.

Diet-induced obesity and aging-induced upregulation of Trib3 interfere with energy homeostasis by downregulating the thermogenic capacity of BAT

Characterized by UCP1 expression and abundant mitochondria, brown adipose tissue (BAT) plays a crucial role in energy balance by converting chemical energy into heat through the cost of ATP production. In this study, it was demonstrated that Trib3 is a critical determinant of BAT-mediated energy expenditure and whole-body energy homeostasis. Under 60% high-fat diet conditions, Trib3 expression in BAT was elevated. Mice deficient in Trib3 are resistant to diet-induced obesity and exhibit improved glucose homeostasis due to enhanced BAT activity. Furthermore, brown adipocyte progenitor cells (APCs) lacking Trib3 exhibited increased proliferation and promoted brown adipocyte differentiation and mitochondrial biogenesis, contributing to the increase in the maximal thermogenic capacity of BAT in Trib3-deficient mice. Mechanistically, it was discovered that Trib3 expression is upregulated by free fatty acids at the transcriptional level and synergistically upregulated by DAG-PKC at the posttranslational level. This occurs through the modulation of COP1-mediated Trib3 protein turnover. Interestingly, the level of Trib3 expression in BAT increased with age. Trib3 knockout mice were protected from aging-related weight gain and impaired glucose homeostasis. These results suggest that Trib3 acts as an obesity- and aging-associated factor that negatively regulates BAT activity and that the loss of Trib3 may provide a beneficial approach to prevent obesity and aging-associated metabolic syndrome by increasing the thermogenic capacity of BAT.

Tribbles pseudokinase 3 promoted renal fibrosis by regulating the expression of DNA damage-inducible transcript 3 in diabetic nephropathy

Diabetic nephropathy (DN) is a severe complication of prolonged diabetes, impacting millions worldwide with an increasing incidence. This study investigates the role of tribbles pseudokinase 3 (TRIB3), a protein implicated in the progression of DN, focusing on its mechanisms underlying glomerular damage. Through analysis of the Gene Expression Omnibus (GEO) database, we identified TRIB, among differentially expressed genes (DEGs) in streptozotocin (STZ)-treated C57BL/6J mice. Both in vitro and in vivo experiments were conducted to examine the effects of TRIB3 inhibition on high glucose (HG)-induced damage in podocytes and DN mouse models. The results demonstrated that TRIB3 inhibition reduced inflammatory responses and extracellular matrix (ECM) production inMPC5 cells, mediated by the downregulation of DNA damage-inducible transcript 3 (DDIT3) - a critical regulator of proinflammatory cytokine secretion and ECM synthesis. Inhibiting TRIB3 decreased inflammatory factors and ECM deposition in diabetic mice in vivo, confirming its pivotal role in DN pathogenesis. These findings indicate that TRIB3 and its interaction with DDIT3 contribute significantly to DN by promoting inflammatory cascades and ECM accumulation, presenting potential therapeutic targets for managing the disease.

Impact of Lipids on Insulin Resistance: Insights from Human and Animal Studies

Insulin resistance (IR) is a complex pathological condition central to metabolic diseases such as type 2 diabetes mellitus (T2DM), cardiovascular disease, non-alcoholic fatty liver disease, and polycystic ovary syndrome (PCOS). This review evaluates the impact of lipids on insulin resistance (IR) by analyzing findings from human and animal studies. The articles were searched on the PubMed database using two keywords: (1) "Role of Lipids AND Insulin Resistance AND Humans" and (2) "Role of Lipids AND Insulin Resistance AND Animal Models". Studies in humans revealed that elevated levels of free fatty acids (FFAs) and triglycerides (TGs) are closely associated with reduced insulin sensitivity, and interventions like metformin and omega-3 fatty acids show potential benefits. In animal models, high-fat diets disrupt insulin signaling and increase inflammation, with lipid mediators such as diacylglycerol (DAG) and ceramides playing significant roles. DAG activates protein kinase C, which eventually impairs insulin signaling, while ceramides inhibit Akt/PKB, further contributing to IR. Understanding these mechanisms is crucial for developing effective prevention and treatment strategies for IR-related diseases.

Interactions between myoblasts and macrophages under high glucose milieus result in inflammatory response and impaired insulin sensitivity

BACKGROUND

Skeletal muscle handles about 80% of insulin-stimulated glucose uptake and become the major organ occurring insulin resistance (IR). Many studies have confirmed the interactions between macrophages and skeletal muscle regulated the inflammation and regeneration of skeletal muscle. However, despite of the decades of research, whether macrophages infiltration and polarization in skeletal muscle under high glucose (HG) milieus results in the development of IR is yet to be elucidated. C2C12 myoblasts are well-established and excellent model to study myogenic regulation and its responses to stimulation. Further exploration of macrophages' role in myoblasts IR and the dynamics of their infiltration and polarization is warranted.

AIM

To evaluate interactions between myoblasts and macrophages under HG, and its effects on inflammation and IR in skeletal muscle.

METHODS

We detected the polarization status of macrophages infiltrated to skeletal muscles of IR mice by hematoxylin and eosin and immunohistochemical staining. Then, we developed an in vitro co-culture system to study the interactions between myoblasts and macrophages under HG milieus. The effects of myoblasts on macrophages were explored through morphological observation, CCK-8 assay, Flow Cytometry, and enzyme-linked immunosorbent assay. The mediation of macrophages to myogenesis and insulin sensitivity were detected by morphological observation, CCK-8 assay, Immunofluorescence, and 2-NBDG assay.

RESULTS

The F4/80 and co-localization of F4/80 and CD86 increased, and the myofiber size decreased in IR group (P < 0.01, g = 6.26). Compared to Mc group, F4/80+CD86+CD206- cells, tumor necrosis factor-α (TNFα), inerleukin-1β (IL-1β) and IL-6 decreased, and IL-10 increased in McM group (P < 0.01, g > 0.8). In McM + HG group, F4/80+CD86+CD206- cells, monocyte chemoattractant protein 1, TNFα, IL-1β and IL-6 were increased, and F4/80+CD206+CD86- cells and IL-10 were decreased compared with Mc + HG group and McM group (P < 0.01, g > 0.8). Compered to M group, myotube area, myotube number and E-MHC were increased in MMc group (P < 0.01, g > 0.8). In MMc + HG group, myotube area, myotube number, E-MHC, GLUT4 and glucose uptake were decreased compared with M + HG group and MMc group (P < 0.01, g > 0.8).

CONCLUSION

Interactions between myoblasts and macrophages under HG milieus results in inflammation and IR, which support that the macrophage may serve as a promising therapeutic target for skeletal muscle atrophy and IR.

Integration of dietary nutrition and TRIB3 action into diabetes mellitus

Despite intensive studies for decades, the common mechanistic correlations among the underlying pathology of diabetes mellitus (DM), its complications, and effective clinical treatments remain poorly characterized. High-quality diets and nutrition therapy have played an indispensable role in the management of DM. More importantly, tribbles homolog 3 (TRIB3), a nutrient-sensing and glucose-responsive regulator, might be an important stress-regulatory switch, linking glucose homeostasis and insulin resistance. Therefore, this review aimed to introduce the latest research progress on the crosstalk between dietary nutrition intervention and TRIB3 in the development and treatment of DM. This study also summarized the possible mechanisms involved in the signaling pathways of TRIB3 action in DM, in order to gain an in-depth understanding of dietary nutrition intervention and TRIB3 in the pathogenesis of DM at the organism level.

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.

Syringin alleviates hepatic fibrosis by enhancing autophagic flux and attenuating ER stress-TRIB3/SMAD3 in diabetic mice

Type 2 diabetes mellitus (T2DM) is a key risk factor for the developing of metabolic liver injury and easily evolving to advanced fibrosis. Syringin (SYR), isolated from Acanthopanax senticosus, has anti-inflammatory, anti-oxidant, and anti-apoptotic properties. However, its hepatoprotective effects and mechanisms in T2DM-induced liver fibrosis remain unclear. Here, we investigated whether syringin (SYR) could serve as a therapeutic agent for liver fibrosis and its mechanism in high-fat diet (HFD)/streptozotocin (STZ)-induced type 2 diabetic mice. C57BL/6 mice were induced with T2DM via HFD and STZ injection and treated with different doses of SYR. Serum lipid parameters and liver function indicators were measured, and hepatic histology and fibrosis were examined. The mechanism of SYR was explored through molecular analyses Results demonstrated SYR improved oral glucose tolerance, decreased the levels of ALT, AST, and AKP, and reduced hepatic lipid deposition in diabetic mice. Moreover, SYR ameliorated epithelial-to-mesenchymal transition to reverse hepatic fibrosis via suppressing TRIB3-SMAD3 interaction to restrain nuclear localization of SMAD3. Strikingly, SYR reversed hyperglycemia-induced deficiency in autophagic flux by regulation of Raptor/mTORC1, triggering nuclear translocation of TFEB to improve autophagosome-lysosomal fusion. In brief, SYR potentially ameliorates hepatic injury and fibrosis by enhancing autophagic flux and inhibing TRIB3 activation in diabetic mice.

The functions and molecular mechanisms of Tribbles homolog 3 (TRIB3) implicated in the pathophysiology of cancer

Currently, cancer ranks as the second leading cause of death worldwide, and at the same time, the burden of cancer continues to increase. The underlying molecular pathways involved in the initiation and development of cancer are the subject of considerable research worldwide. Further understanding of these pathways may lead to new cancer treatments. Growing data suggest that Tribble's homolog 3 (TRIB3) is essential in oncogenesis in many types of cancer. The mammalian tribbles family's proteins regulate various cellular and physiological functions, such as the cell cycle, stress response, signal transduction, propagation, development, differentiation, immunity, inflammatory processes, and metabolism. To exert their activities, Tribbles proteins must alter key signaling pathways, including the mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3 kinase (PI3K)/AKT pathways. Recent evidence supports that TRIB3 dysregulation has been linked to various diseases, including tumor development and chemoresistance. It has been speculated that TRIB3 may either promote or inhibit the onset and development of cancer. However, it is still unclear how TRIB3 performs this dual function in cancer. In this review, we present and discuss the most recent data on the role of TRIB3 in cancer pathophysiology and chemoresistance. Furthermore, we describe in detail the molecular mechanism TRIB3 regulates in cancer.

Detrimental effects of branched-chain amino acids in glucose tolerance can be attributed to valine induced glucotoxicity in skeletal muscle

Objective

Current data regarding the roles of branched-chain amino acids (BCAA) in metabolic health are rather conflicting, as positive and negative effects have been attributed to their intake.

Methods

To address this, individual effects of leucine and valine were elucidated in vivo (C57BL/6JRj mice) with a detailed phenotyping of these supplementations in high-fat (HF) diets and further characterization with in vitro approaches (C2C12 myocytes).

Results

Here, we demonstrate that under HF conditions, leucine mediates beneficial effects on adiposity and insulin sensitivity, in part due to increasing energy expenditure—likely contributing partially to the beneficial effects of a higher milk protein intake. On the other hand, valine feeding leads to a worsening of HF-induced health impairments, specifically reducing glucose tolerance/insulin sensitivity. These negative effects are driven by an accumulation of the valine-derived metabolite 3-hydroxyisobutyrate (3-HIB). Higher plasma 3-HIB levels increase basal skeletal muscle glucose uptake which drives glucotoxicity and impairs myocyte insulin signaling.

Conclusion

These data demonstrate the detrimental role of valine in an HF context and elucidate additional targetable pathways in the etiology of BCAA-induced obesity and insulin resistance.

Circulating TRB3 and GRP78 levels in type 2 diabetes patients: crosstalk between glucose homeostasis and endoplasmic reticulum stress

PURPOSE

Endoplasmic reticulum (ER) stress is implicated in the development of type 2 diabetes mellitus (T2DM) and insulin resistance. Tribbles homolog 3 (TRB3) is a pseudokinase upregulated by ER stress and hyperglycemia. Glucose-regulated protein 78 (GRP78) is an ER stress protein that is overexpressed under ER stress conditions. The current study aimed to investigate serum levels of TRB3 and GRP78, as an ER stress marker, in T2DM patients and their correlations with the metabolic profile.

METHODS

Fifty-seven patients with type 2 diabetes and 23 healthy control subjects were evaluated for serum concentrations of TRB3, GRP78, and AGEs by enzyme-linked immunosorbent assay (ELISA). Fasting plasma glucose (FPG), HbA1c, lipid profile, TNF-α and insulin were also measured, and insulin resistance was calculated using a homeostasis model assessment of insulin resistance (HOMA-IR).

RESULTS

Serum concentrations of TRB3, GRP78, AGEs, and TNF-α were significantly higher in T2DM patients compared to the healthy controls. Moreover, a statistically significant positive correlation was observed between plasma concentrations of TRB3 and FPG, HbA1c, HOMA-IR, and AGE. GRP78 levels were positively correlated with HbA1c and AGEs. There was also a positive correlation between GRP78 and TRB3. AGEs levels were positively correlated with the levels of FPG, HbA1c, HOMA-IR, and TNF-α.

CONCLUSION

The current findings suggest that TRB3 and GRP78 may contribute to the pathogenesis of T2DM and might be considered as a therapeutic targets for the treatment of this disease.

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

CONTEXT

The upregulation of TRIB3 (Tribbles homolog 3), a stress-inducible gene encoding a pseudokinase, has been implicated in the development of insulin resistance in the skeletal muscle and liver of patients with obesity and type 2 diabetes. However, there is little information regarding TRIB3 expression in human adipose tissue.

OBJECTIVE

To investigate whether TRIB3 expression is dysregulated in human adipose tissue in the context of obesity and type 2 diabetes and whether TRIB3 expression in adipose tissues is associated with insulin resistance.

METHODS

We measured metabolic parameters and TRIB3 expression in abdominal subcutaneous and visceral adipose tissue in obese (with or without type 2 diabetes) and normal-weight women. Regulation of TRIB3 expression was studied in human adipocytes.

RESULTS

TRIB3 expression in both fat depots was higher in patients with obesity and/or type 2 diabetes; in addition, the expression level was significantly associated with insulin resistance. Incubating adipocytes under conditions mimicking the microenvironment of obese adipose tissue, including increased endoplasmic reticulum (ER) stress, induced TRIB3 expression. In human adipocytes, the overexpression of TRIB3 impaired insulin-stimulated protein kinase B (AKT) phosphorylation and caused dysregulation of the transcription of genes encoding bioactive molecules released from adipocytes, such as proinflammatory cytokines, adiponectin, and leptin. Pioglitazone, an insulin-sensitizing agent, reduced both these effects of TRIB3 and the ER stressor-induced expression of TRB3.

CONCLUSION

Our data indicate that TRIB3 expression in adipose tissue is enhanced in patients with obesity and suggest that increased TRIB3 dysregulates adipocyte function, which may contribute to the development of insulin resistance.

TRB3 Deletion Has a Limited Effect on Milk Fat Synthesis and Milk Fat Depression in C57BL/6N Mice

BACKGROUND

Regulation of the endoplasmic reticulum (ER) stress pathway is critical to mammary epithelial cell function throughout pregnancy, lactation, and involution. Treatment with trans-10, cis-12 conjugated linoleic acid (t10c12CLA) suppresses mammary lipogenesis and stimulates the ER stress pathway. The ER stress pathway includes tribbles pseudokinase 3 (TRB3), a protein that regulates cellular energy and insulin signaling.

OBJECTIVES

Our objective was to describe the effect of TRB3 deficiency on milk fat synthesis and determine if TRB3 deficiency protects against suppression of mammary lipogenesis.

METHODS

First, mammary Trb3 expression was observed throughout pregnancy and lactation using ancillary microarray data (n = 4/time point). Second, intake, litter growth, and milk clot fatty acid (FA) profile of Trb3 knockout (KO) C57BL/6N mice were compared with wild-type (WT) and heterozygous (HET) mice throughout first (n ≥ 8/group) and second (n ≥ 6/group) lactation. Lastly, the interaction between Trb3 genotype and 2 treatments that suppress mammary lipogenesis, t10c12CLA and high safflower oil (HO) diet, was investigated in a 2 × 2 factorial design (n ≥ 6/group).

RESULTS

Trb3 expression was higher during late pregnancy and lactation. Trb3 KO and HET mice had lower feed intake, dam weight, and litter growth throughout first, but not second, lactation than WT mice. Treatment with t10c12CLA decreased litter growth (28%; P < 0.0001) and feed intake (8%; P < 0.0001) regardless of Trb3 genotype. When fed the HO diet, Trb3 KO mice had 17% higher mammary de novo synthesized FAs (<16 carbons; P int = 0.002) than WT mice. Mammary ER stress and lipogenic genes were mostly unaltered by Trb3 deficiency.

CONCLUSIONS

Overall, TRB3 plays a minor role in regulating mammary lipogenesis, because Trb3 deficiency had only a limited protective effect against diet-induced suppression of lipogenesis.

PPARγ and TGFβ-Major Regulators of Metabolism, Inflammation, and Fibrosis in the Lungs and Kidneys

Peroxisome proliferator-activated receptor gamma (PPARγ) is a type II nuclear receptor, initially recognized in adipose tissue for its role in fatty acid storage and glucose metabolism. It promotes lipid uptake and adipogenesis by increasing insulin sensitivity and adiponectin release. Later, PPARγ was implicated in cardiac development and in critical conditions such as pulmonary arterial hypertension (PAH) and kidney failure. Recently, a cluster of different papers linked PPARγ signaling with another superfamily, the transforming growth factor beta (TGFβ), and its receptors, all of which play a major role in PAH and kidney failure. TGFβ is a multifunctional cytokine that drives inflammation, fibrosis, and cell differentiation while PPARγ activation reverses these adverse events in many models. Such opposite biological effects emphasize the delicate balance and complex crosstalk between PPARγ and TGFβ. Based on solid experimental and clinical evidence, the present review summarizes connections and their implications for PAH and kidney failure, highlighting the similarities and differences between lung and kidney mechanisms as well as discussing the therapeutic potential of PPARγ agonist pioglitazone.

Modulation of TRIB3 and Macrophage Phenotype to Attenuate Insulin Resistance After Downhill Running in Mice

Eccentric exercise training accompanied by a low-fat diet can prevent insulin resistance (IR) and is currently an effective method for the treatment of IR induced by high-fat diet (HFD)-associated obesity. However, the molecular mechanisms underlying this improvement of IR in adipose tissue are still not completely clear. In this study, 5–6-week-old male mice were randomly divided into a standard control diet (SCD) group (SC, n = 12) and a HFD group (HF, n = 72). After 12 weeks, 12 mice in each group were randomly sacrificed. The remaining mice in the HF group were randomly submitted to one of the following experimental protocols for 8 weeks: obesity-HFD-sedentary (OHF-Sed, n = 14), obesity-HFD-exercise (OHF-Ex, n = 16), obesity-SCD-sedentary (OSC-Sed, n = 14), and obesity-SCD-exercise (OSC-Ex, n = 16). All obese mice in the exercise group were subjected to downhill running. Half of the mice in each group received an insulin injection (0.75 U/kg) before sample collection. Epididymal fat was removed and weighed. Adipocyte size and inflammatory cell infiltration were observed by H&E staining. Both basal and insulin-stimulated GLUT4 fluorescence and protein contents were detected by immunofluorescence and Western blot. Levels of IL-1β and IL-10 were detected by ELISA. Protein contents of iNOS, Arg-1, TRIB3, p-AKT, and AKT were determined by Western blot. CD86 and CD206 fluorescence were determined by immunofluorescence. The results showed that a HFD for 12 weeks induced IR accompanied by adipose tissue macrophages M1 polarization (increased iNOS protein content and CD86 fluorescence) and TRIB3-AKT activation. Downhill running accompanied by a low-fat diet attenuated IR (p < 0.01), reduced inflammation levels (increased IL-10 protein content and decreased IL-1β protein content), inhibited adipose tissue macrophages M1 polarization (decreased iNOS protein content and CD86 fluorescence) and promoted M2 polarization (increased Arg-1 protein content and CD206 fluorescence), and suppressed TRIB3-AKT signaling. We concluded that downhill running accompanied by dietary fat regulation attenuates HFD-related IR in mice, which may be associated with reduced TRIB3-AKT signaling and activated M2 macrophages in adipose tissue.

Integrated transcriptomic and neuroimaging brain model decodes biological mechanisms in aging and Alzheimer's disease

Both healthy aging and Alzheimer's disease (AD) are characterized by concurrent alterations in several biological factors. However, generative brain models of aging and AD are limited in incorporating the measures of these biological factors at different spatial resolutions. Here, we propose a personalized bottom-up spatiotemporal brain model that accounts for the direct interplay between hundreds of RNA transcripts and multiple macroscopic neuroimaging modalities (PET, MRI). In normal elderly and AD participants, the model identifies top genes modulating tau and amyloid-β burdens, vascular flow, glucose metabolism, functional activity, and atrophy to drive cognitive decline. The results also revealed that AD and healthy aging share specific biological mechanisms, even though AD is a separate entity with considerably more altered pathways. Overall, this personalized model offers novel insights into the multiscale alterations in the elderly brain, with important implications for identifying effective genetic targets for extending healthy aging and treating AD progression.

The many actions of insulin in skeletal muscle, the paramount tissue determining glycemia

As the principal tissue for insulin-stimulated glucose disposal, skeletal muscle is a primary driver of whole-body glycemic control. Skeletal muscle also uniquely responds to muscle contraction or exercise with increased sensitivity to subsequent insulin stimulation. Insulin's dominating control of glucose metabolism is orchestrated by complex and highly regulated signaling cascades that elicit diverse and unique effects on skeletal muscle. We discuss the discoveries that have led to our current understanding of how insulin promotes glucose uptake in muscle. We also touch upon insulin access to muscle, and insulin signaling toward glycogen, lipid, and protein metabolism. We draw from human and rodent studies in vivo, isolated muscle preparations, and muscle cell cultures to home in on the molecular, biophysical, and structural elements mediating these responses. Finally, we offer some perspective on molecular defects that potentially underlie the failure of muscle to take up glucose efficiently during obesity and type 2 diabetes.

Nicorandil attenuates high glucose-induced insulin resistance by suppressing oxidative stress-mediated ER stress PERK signaling pathway

INTRODUCTION

Glucose-induced insulin resistance is a typical character of diabetes. Nicorandil is now widely used in ischemic heart disease. Nicorandil shows protective effects against oxidative and endoplasmic reticulum (ER) stress, which are involved in insulin resistance. Here, we investigated mechanisms of nicorandil's novel pharmacological activity on insulin resistance in diabetes.

RESEARCH DESIGN AND METHODS

Nicorandil was administrated to streptozotocin-induced animals with diabetes and high glucose exposed skeletal muscle cells. Insulin resistance and glucose tolerance were evaluated. Molecular mechanisms concerning oxidative stress, ER stress signaling activation and glucose uptake were assessed.

RESULTS

Nicorandil attenuated high glucose-induced insulin resistance without affecting fasting blood glucose and glucose tolerance in whole body and skeletal muscle in rats with diabetes. Nicorandil treatment suppressed protein kinase C/nicotinamide adenine dinucleotide phosphate oxidases system activities by reducing cytoplasmic free calcium level in skeletal muscle cells exposed to high glucose. As a result, the oxidative stress-mediated ER stress protein kinase RNA-like endoplasmic reticulum kinase (PERK)/eukaryotic initiation factor 2α/activating transcription factor 4/CEBP homologous protein/tribbles homolog (TRB)3 signaling pathway activation was inhibited. Nicorandil downregulated expression of TRB3 and thus facilitated Akt phosphorylation in response to insulin stimulation, leading to glucose transporter4 plasma membrane translocation which promoted glucose uptake capability of skeletal muscle cells.

CONCLUSIONS

By reducing cytoplasmic calcium, nicorandil alleviated high glucose-induced insulin resistance by inhibiting oxidative stress-mediated ER stress PERK pathway.

Endoplasmic reticulum stress and unfolded protein response in cardiovascular diseases

Cardiovascular diseases (CVDs), such as ischaemic heart disease, cardiomyopathy, atherosclerosis, hypertension, stroke and heart failure, are among the leading causes of morbidity and mortality worldwide. Although specific CVDs and the associated cardiometabolic abnormalities have distinct pathophysiological and clinical manifestations, they often share common traits, including disruption of proteostasis resulting in accumulation of unfolded or misfolded proteins in the endoplasmic reticulum (ER). ER proteostasis is governed by the unfolded protein response (UPR), a signalling pathway that adjusts the protein-folding capacity of the cell to sustain the cell's secretory function. When the adaptive UPR fails to preserve ER homeostasis, a maladaptive or terminal UPR is engaged, leading to the disruption of ER integrity and to apoptosis. ER stress functions as a double-edged sword, with long-term ER stress resulting in cellular defects causing disturbed cardiovascular function. In this Review, we discuss the distinct roles of the UPR and ER stress response as both causes and consequences of CVD. We also summarize the latest advances in our understanding of the importance of the UPR and ER stress in the pathogenesis of CVD and discuss potential therapeutic strategies aimed at restoring ER proteostasis in CVDs.

Control of Cell Growth and Proliferation by the Tribbles Pseudokinase: Lessons from Drosophila

Simple Summary

Tribbles pseudokinases represent a sub-branch of the CAMK (Ca²⁺/calmodulin-dependent protein kinase) subfamily and are associated with disease-associated signaling pathways associated with various cancers, including melanoma, lung, liver, and acute leukemia. The ability of this class of molecules to regulate cell proliferation was first recognized in the model organism Drosophila and the fruit fly genetic model and continues to provide insight into the molecular mechanism by which this family of adapter molecules regulates both normal development and disease associated with corruption of their proper regulation and function.

Abstract

The Tribbles (Trib) family of pseudokinase proteins regulate cell growth, proliferation, and differentiation during normal development and in response to environmental stress. Mutations in human Trib isoforms (Trib1, 2, and 3) have been associated with metabolic disease and linked to leukemia and the formation of solid tumors, including melanomas, hepatomas, and lung cancers. Drosophila Tribbles (Trbl) was the first identified member of this sub-family of pseudokinases and shares a conserved structure and similar functions to bind and direct the degradation of key mediators of cell growth and proliferation. Common Trib targets include Akt kinase (also known as protein kinase B), C/EBP (CAAT/enhancer binding protein) transcription factors, and Cdc25 phosphatases, leading to the notion that Trib family members stand athwart multiple pathways modulating their growth-promoting activities. Recent work using the Drosophila model has provided important insights into novel facets of conserved Tribbles functions in stem cell quiescence, tissue regeneration, metabolism connected to insulin signaling, and tumor formation linked to the Hippo signaling pathway. Here we highlight some of these recent studies and discuss their implications for understanding the complex roles Tribs play in cancers and disease pathologies.

Tribbles Homolog 3-Mediated Vascular Insulin Resistance Contributes to Hypoxic Pulmonary Hypertension in Intermittent Hypoxia Rat Model

This study aimed to investigate the role of vascular insulin resistance (VIR) and Tribbles homolog 3 (TRIB3) in the pathogenesis of hypoxia-induced pulmonary hypertension (HPH). Rats were subjected to low air pressure and low oxygen intermittently for 4 weeks to induce HPH. The mean right ventricular pressure (mRVP), mean pulmonary arterial pressure (mPAP), and right ventricular index (RVI) were significantly increased in HPH rats. Pulmonary arteries from HPH rats showed VIR with reduced vasodilating effect of insulin. The protein levels of peroxisome proliferator-activated receptor gamma (PPARγ), phosphoinositide 3-kinase (PI3K), phosphorylations of Akt, and endothelial nitric oxide (NO) synthase (eNOS) were decreased, and TRIB3 and phosphorylated extracellular signal-regulated protein kinases (ERK1/2) were increased in pulmonary arteries of HPH rats. Early treatment of pioglitazone (PIO) partially reversed the development of HPH, improved insulin-induced vasodilation, and alleviated the imbalance of the insulin signaling. The overexpression of TRIB3 in rat pulmonary arterial endothelial cells (PAECs) reduced the levels of PPARγ, PI3K, phosphorylated Akt (p-Akt), and phosphorylated eNOS (p-eNOS) and increased p-ERK1/2 and the synthesis of endothelin-1 (ET-1), which were further intensified under hypoxic conditions. Moreover, TRIB3 knockdown caused significant improvement in Akt and eNOS phosphorylations and, otherwise, a reduction of ERK1/2 activation in PAECs after hypoxia. In conclusion, impaired insulin-induced pulmonary vasodilation and the imbalance of insulin-induced signaling mediated by TRIB3 upregulation in the endothelium contribute to the development of HPH. Early PIO treatment improves vascular insulin sensitivity that may help to limit the progression of hypoxic pulmonary hypertension.

Cardiometabolic-Based Chronic Disease, Adiposity and Dysglycemia Drivers: JACC State-of-the-Art Review

A new cardiometabolic-based chronic disease (CMBCD) model is presented that provides a basis for early and sustainable, evidence-based therapeutic targeting to promote cardiometabolic health and mitigate the development and ravages of cardiovascular disease. In the first part of this JACC State-of-the-Art Review, a framework is presented for CMBCD, focusing on 3 primary drivers (genetics, environment, and behavior) and 2 metabolic drivers (adiposity and dysglycemia) with applications to 3 cardiovascular endpoints (coronary heart disease, heart failure, and atrial fibrillation). Specific mechanistic pathways are presented configuring early primary drivers with subsequent adiposity, insulin resistance, β-cell dysfunction, and metabolic syndrome, leading to cardiovascular disease. The context for building this CMBCD model is to expose actionable targets for prevention to achieve optimal cardiovascular outcomes. The tactical implementation of this CMBCD model is the subject of second part of this JACC State-of-the-Art Review.

Cardiometabolic-Based Chronic Disease, Adiposity and Dysglycemia Drivers: JACC State-of-the-Art Review

A new cardiometabolic-based chronic disease (CMBCD) model is presented that provides a basis for early and sustainable, evidence-based therapeutic targeting to promote cardiometabolic health and mitigate the development and ravages of cardiovascular disease. In the first part of this JACC State-of-the-Art Review, a framework is presented for CMBCD, focusing on 3 primary drivers (genetics, environment, and behavior) and 2 metabolic drivers (adiposity and dysglycemia) with applications to 3 cardiovascular endpoints (coronary heart disease, heart failure, and atrial fibrillation). Specific mechanistic pathways are presented configuring early primary drivers with subsequent adiposity, insulin resistance, β-cell dysfunction, and metabolic syndrome, leading to cardiovascular disease. The context for building this CMBCD model is to expose actionable targets for prevention to achieve optimal cardiovascular outcomes. The tactical implementation of this CMBCD model is the subject of second part of this JACC State-of-the-Art Review.

miR-3188 (rs7247237-C>T) Single-Nucleotide Polymorphism Is Associated With the Incidence of Vascular Complications in Chinese Patients With Type 2 Diabetes

miR-3188, one of the earliest discovered microRNAs, is involved in regulating the mTOR-p-PI3K/AKT pathway, thus affecting the progression of diabetic complications. In this study, we observed that the miR-3188 (rs7247237-C>T) polymorphism not only affected the production of nitric oxide (NO) production in endothelial cells, but also significantly associated with the incidence of vascular complications in Chinese patients with type 2 diabetes. Mechanistic analyses indicate that miR-3188 (rs7247237-T) polymorphism inhibited its own expression and upregulated the expression of gstm1 and trib3, which impairs NO production in human endothelial cells through inactivating AKT/eNOS signal transduction pathway. In addition, our clinical retrospective study indicated that, compared with patients with the CC genotype (n = 351), patients with rs7247237 TT + CT genotypes (n = 580) exhibited an increased risk of major vascular events during intensive glucose control treatment (hazard ratio = 1.560; 95% CI: 1.055-2.307, P = 0.025). Simultaneously, the risk of major vascular events was marginally decreased in patients with the CC genotype during intensive glucose control treatment compared with standard treatment (hazard ratio = 0.666; 95% CI: 0.433-1.016, P = 0.053). Our findings indicate that the miR-3188 (rs7247237-C>T) polymorphism is associated with the incidence of vascular complications in Chinese patients with type 2 diabetes, likely due to its remarkable effect on miR-3188 expression.

Cardiometabolic-Based Chronic Disease, Adiposity and Dysglycemia Drivers: JACC State-of-the-Art Review

A new cardiometabolic-based chronic disease (CMBCD) model is presented that provides a basis for early and sustainable, evidence-based therapeutic targeting to promote cardiometabolic health and mitigate the development and ravages of cardiovascular disease. In the first part of this JACC State-of-the-Art Review, a framework is presented for CMBCD, focusing on 3 primary drivers (genetics, environment, and behavior) and 2 metabolic drivers (adiposity and dysglycemia) with applications to 3 cardiovascular endpoints (coronary heart disease, heart failure, and atrial fibrillation). Specific mechanistic pathways are presented configuring early primary drivers with subsequent adiposity, insulin resistance, β-cell dysfunction, and metabolic syndrome, leading to cardiovascular disease. The context for building this CMBCD model is to expose actionable targets for prevention to achieve optimal cardiovascular outcomes. The tactical implementation of this CMBCD model is the subject of second part of this JACC State-of-the-Art Review.

Cardiometabolic-Based Chronic Disease, Adiposity and Dysglycemia Drivers: JACC State-of-the-Art Review

A new cardiometabolic-based chronic disease (CMBCD) model is presented that provides a basis for early and sustainable, evidence-based therapeutic targeting to promote cardiometabolic health and mitigate the development and ravages of cardiovascular disease. In the first part of this JACC State-of-the-Art Review, a framework is presented for CMBCD, focusing on 3 primary drivers (genetics, environment, and behavior) and 2 metabolic drivers (adiposity and dysglycemia) with applications to 3 cardiovascular endpoints (coronary heart disease, heart failure, and atrial fibrillation). Specific mechanistic pathways are presented configuring early primary drivers with subsequent adiposity, insulin resistance, β-cell dysfunction, and metabolic syndrome, leading to cardiovascular disease. The context for building this CMBCD model is to expose actionable targets for prevention to achieve optimal cardiovascular outcomes. The tactical implementation of this CMBCD model is the subject of second part of this JACC State-of-the-Art Review.

TRB3 regulates skeletal muscle mass in food deprivation-induced atrophy

Tribbles 3 (TRB3) is a pseudokinase that has been found in multiple tissues in response to various stress stimuli, such as nutrient deprivation and endoplasmic reticulum (ER) stress. We recently found that TRB3 has the potential to regulate skeletal muscle mass at the basal state. However, it has not yet been explored whether TRB3 regulates skeletal muscle mass under atrophic conditions. Here, we report that food deprivation for 48 h in mice significantly reduces muscle mass by ∼15% and increases TRB3 expression, which is associated with increased ER stress. Interestingly, inhibition of ER stress in C2C12 myotubes reduces food deprivation-induced expression of TRB3 and muscle-specific E3-ubiquitin ligases. In further in vivo experiments, muscle-specific TRB3 transgenic mice increase food deprivation-induced muscle atrophy compared with wild-type (WT) littermates presumably by the increased proteolysis. On the other hand, TRB3 knockout mice ameliorate food deprivation-induced atrophy compared with WT littermates by preserving a higher protein synthesis rate. These results indicate that TRB3 plays a pivotal role in skeletal muscle mass regulation under food deprivation-induced muscle atrophy and TRB3 could be a pharmaceutical target to prevent skeletal muscle atrophy.-Choi, R. H., McConahay, A., Silvestre, J. G., Moriscot, A. S., Carson, J. A., Koh, H.-J. TRB3 regulates skeletal muscle mass in food deprivation-induced atrophy.

Early Imaging Biomarker of Myocardial Glucose Adaptations in High-Fat-Diet-Induced Insulin Resistance Model by Using 18F-FDG PET and [U-13C]glucose Nuclear Magnetic Resonance Tracer

Background

High-fat diet (HFD) induces systemic insulin resistance leading to myocardial dysfunction. We aim to characterize the early adaptations of myocardial glucose utility to HFD-induced insulin resistance.

Methods

Male Sprague–Dawley rats were assigned into two groups, fed a regular chow diet or HFD ad libitum for 10 weeks. We used in vivo imaging of cardiac magnetic resonance (CMR), ¹⁸F-FDG PET, and ex vivo nuclear magnetic resonance (NMR) metabolomic analysis for the carbon-13-labeled glucose ([U-¹³C]Glc) perfused myocardium.

Results

As compared with controls, HFD rats had a higher ejection fraction and a smaller left ventricular end-systolic volume (P < 0.05), with SUV_max of myocardium on ¹⁸F-FDG PET significantly increased in 4 weeks (P < 0.005). The [U-¹³C]Glc probed the increased glucose uptake being metabolized into pyruvate and acetyl-CoA, undergoing oxidative phosphorylation via the tricarboxylic acid (TCA) cycle, and then synthesized into glutamic acid and glutamine, associated with overexpressed LC3B (P < 0.05).

Conclusions

HFD-induced IR associated with increased glucose utility undergoing oxidative phosphorylation via the TCA cycle in the myocardium is supported by overexpression of glucose transporter, acetyl-CoA synthase. Noninvasive imaging biomarker has potentials in detecting the metabolic perturbations prior to the decline of the left ventricular function.

Susceptibility of brain atrophy to TRIB3 in Alzheimer's disease, evidence from functional prioritization in imaging genetics

The joint modeling of brain imaging information and genetic data is a promising research avenue to highlight the functional role of genes in determining the pathophysiological mechanisms of Alzheimer's disease (AD). However, since genome-wide association (GWA) studies are essentially limited to the exploration of statistical correlations between genetic variants and phenotype, the validation and interpretation of the findings are usually nontrivial and prone to false positives. To address this issue, in this work, we investigate the functional genetic mechanisms underlying brain atrophy in AD by studying the involvement of candidate variants in known genetic regulatory functions. This approach, here termed functional prioritization, aims at testing the sets of gene variants identified by high-dimensional multivariate statistical modeling with respect to known biological processes to introduce a biology-driven validation scheme. When applied to the Alzheimer's Disease Neuroimaging Initiative (ADNI) cohort, the functional prioritization allowed for identifying a link between tribbles pseudokinase 3 (TRIB3) and the stereotypical pattern of gray matter loss in AD, which was confirmed in an independent validation sample, and that provides evidence about the relation between this gene and known mechanisms of neurodegeneration.

Matrine Inhibits Neuroblastoma Cell Proliferation and Migration by Enhancing Tribbles 3 Expression

Neuroblastoma is a major contributor of cancer-specific mortality. Although remarkable enhancement has been achieved in the treatment of neuroblastoma in patients with early stage disease, limited progress has been made in the treatment of patients with high-risk neuroblastoma. Thus, innovative approaches are required to achieve further improvements in neuroblastoma patient survival outcomes. The major alkaloid obtained from Sophora flavescens Ait, matrine, has been shown to counteract malignancy in various kinds of cancers. In the current study, we evaluated the effects of matrine on the migration and proliferation of neuroblastoma cells. Cell cycle analysis coupled with Transwell and wound healing experiments showed that matrine triggers G₂/M cell cycle arrest and suppresses neuroblastoma migration. This effect of matrine is due to upregulation of TRB3 expression followed by inhibition of the PI3K/AKT activation. Consistent with the in vitro data, growth of xenograft cancer was also suppressed by matrine. Our results indicate that matrine inhibits neuroblastoma cell proliferation and migration by enhancing TRB3 expression, suggesting that matrine may serve as a promising agent for the treatment of neuroblastoma.

TRIB3 limits FGF21 induction during in vitro and in vivo nutrient deficiencies by inhibiting C/EBP-ATF response elements in the Fgf21 promoter

Mammals must be able to endure periods of limited food availability, and the liver plays a central role in the adaptation to nutritional stresses. TRIB3 (Tribbles homolog 3) is a cellular stress-inducible gene with a liver-centric expression pattern and it has been implicated in stress response regulation and metabolic control. In the current article, we study the involvement of TRIB3 in responses to nutrient deficiencies, including fasting for up to 48 h in mice. We show that hepatic expression of Trib3 is increased after 48 h of fasting and mice with a targeted deletion of the Trib3 gene present elevated hepatic triglyceride content and liver weight at 48 h, along with an upregulation of lipid utilization genes in the liver. Further, hepatic and serum levels of the metabolic stress hormone FGF21 are considerably increased in 48-h-fasted Trib3 knockout mice compared to wild type. Trib3 deficiency also leads to elevated FGF21 levels in the mouse liver during essential amino acid deficiency and in cultured mouse embryonic fibroblasts during glucose starvation. Reporter assays reveal that TRIB3 regulates FGF21 by inhibiting ATF4-mediated, C/EBP-ATF site-dependent activation of Fgf21 transcription. Based on chromatin immunoprecipitation from mouse liver, the binding of TRIB3 and ATF4, a transcription factor known to physically interact with TRIB3, is significantly increased at the Fgf21 promoter following 48 h of fasting. Thus, under nutrient-limiting conditions that stimulate ATF4 activity, TRIB3 is implicated in the regulation of metabolic adaptation by restraining the transcription of Fgf21.

High glucose contributes to the proliferation and migration of non-small cell lung cancer cells via GAS5-TRIB3 axis

Despite the growing number of studies exhibited an association of diabetes mellitus (DM) and lung cancer progression, the concrete mechanism of DM aggravating lung cancer has not been elucidated. This study was to investigate whether and how high glucose (HG) contribute to the proliferation and migration of non-small cell lung cancer (NSCLC) cells in vitro. In the present study, we confirmed that HG promoted the proliferation and migration of NSCLC cells, and also induced an anti-apoptosis effect on NSCLC cells. Moreover, HG inhibited the expression of GAS5 in NSCLC cells but elevated the protein level of TRIB3. GAS5 overexpression promoted the degradation of TRIB3 protein by ubiquitination and inhibited the HG induced-proliferation, anti-apoptosis and migration of NSCLC cells. Importantly, TRIB3 overexpression reversed the effects of GAS5 on the HG-treated NSCLC cells. Taken together, down-regulated GAS5 by HG significantly enhanced the proliferation, anti-apoptosis and migration in NSCLC cells through TRIB3, thus promoting the carcinogenesis of NSCLC.

Statin therapy causes gut dysbiosis in mice through a PXR-dependent mechanism

BACKGROUND

Statins are a class of therapeutics used to regulate serum cholesterol and reduce the risk of heart disease. Although statins are highly effective in removing cholesterol from the blood, their consumption has been linked to potential adverse effects in some individuals. The most common events associated with statin intolerance are myopathy and increased risk of developing type 2 diabetes mellitus. However, the pathological mechanism through which statins cause these adverse effects is not well understood.

RESULTS

Using a murine model, we describe for the first time profound changes in the microbial composition of the gut following statin treatment. This remodelling affected the diversity and metabolic profile of the gut microbiota and was associated with reduced production of butyrate. Statins altered both the size and composition of the bile acid pool in the intestine, tentatively explaining the observed gut dysbiosis. As also observed in patients, statin-treated mice trended towards increased fasting blood glucose levels and weight gain compared to controls. Statin treatment affected the hepatic expression of genes involved in lipid and glucose metabolism. Using gene knockout mice, we demonstrated that the observed effects were mediated through pregnane X receptor (PXR).

CONCLUSION

This study demonstrates that statin therapy drives a profound remodelling of the gut microbiota, hepatic gene deregulation and metabolic alterations in mice through a PXR-dependent mechanism. Since the demonstrated importance of the intestinal microbial community in host health, this work provides new perspectives to help prevent the statin-associated unintended metabolic effects.