SOCS-1 and SOCS-3 block insulin signaling by ubiquitin-mediated degradation of IRS1 and IRS2

Low-intensity exercise prevents cardiac inflammation through the NF-κB/TNFα pathway in insulin-resistant male rats

Our previously published results have proven that low-intensity exercise, equivalent to brisk walking, is beneficial in managing cardiac insulin resistance in post-weaning male rats exposed to a fructose-rich diet. Still, its role in protecting against cardiac inflammation is unclear. This experiment was designed to investigate the preventive effect of low-intensity exercise on cardiac inflammation in male post-weaning rats exposed to a fructose-rich diet (10%). Male Wistar rats were randomly assigned to a sedentary control group, a sedentary group with fructose overload, and a fructose overload group subjected to treadmill exercise for nine weeks. Protein expression of cardiac inducible nitric oxide synthase (iNOS), matrix metalloproteinase 9, as well as cellular localization/phosphorylation of nuclear factor kappa B (NF-κB), and α1 and α2 subunits of sodium-potassium ATPase pump (Na/K-ATPase) was determined. Additionally, gene expression of tumor necrosis factor α (TNFα) and suppressor of cytokine signaling 3 (SOCS3) was examined. The results demonstrate that a chronic fructose-rich diet in sedentary rats elevates the expression of key inflammatory markers, including SOCS3, TNFα, NF-κB, and iNOS, as well as the plasma membrane α1 and α2 subunits. Exercise prevented alterations induced by a fructose-rich diet, except iNOS expression. Additionally, exercise increased the protein expression of the α1 and α2 subunits of Na/K-ATPase in the lysate of fructose-fed rats. These findings suggest that low-intensity exercise is an effective non-invasive strategy for cardioprotection, helping to prevent inflammation by modulating TNFα and NF-κB expression in insulin-resistant hearts of post-weaning male rats.

Renin angiotensin system-induced muscle wasting: putative mechanisms and implications for clinicians

Renin angiotensin system (RAS) alters various mechanisms related to muscle wasting. The RAS system consists of classical and non-classical pathways, which mostly function differently. Classical RAS pathway, operates through angiotensin II (AngII) and angiotensin type 1 receptors, is associated with muscle wasting and sarcopenia. On the other hand, the non-classical RAS pathway, which operates through angiotensin 1-7 and Mas receptor, is protective against sarcopenia. The classical RAS pathway might induce muscle wasting by variety of mechanisms. AngII reduces body weight, via reduction in food intake, possibly by decreasing hypothalamic expression of orexin and neuropeptide Y, insulin like growth factor-1 (IGF-1) and mammalian target of rapamycin (mTOR), signaling, AngII increases skeletal muscle proteolysis by forkhead box transcription factors (FOXO), caspase activation and muscle RING-finger protein-1 transcription. Furthermore, AngII infusion in skeletal muscle reduces phospho-Bad (Ser136) expression and induces apoptosis through increased cytochrome c release and DNA fragmentation. Additionally, Renin angiotensin system activation through AT1R and AngII stimulates tumor necrosis factor-α, and interleukin-6 which induces muscle wasting, Last but not least classical RAS pathway, induce oxidative stress, disturb mitochondrial energy metabolism, and muscle satellite cells which all lead to muscle wasting and decrease muscle regeneration. On the contrary, the non-classical RAS pathway functions oppositely to mitigate these mechanisms and protects against muscle wasting. In this review, we summarize the mechanisms of RAS-induced muscle wasting and putative implications for clinical practice. We also emphasize the areas of uncertainties and suggest potential research areas.

Effects of Medium Cut-Off Dialyzers on Fat Tissue and Muscle Mass Indices

BACKGROUND

Medium cut-off (MCO) dialyzers are designed to provide clearance of large-middle molecular weight uremic toxins and cytokines that are also responsible for the pathogenesis of sarcopenia.

AIM

To investigate the short- and long-term effects of MCO dialyzers on fat and muscle mass.

METHODS

This single-center prospective, cross-over study includes 20 maintenance hemodialysis (MHD) patients treated with low-flux (LF) dialyzers. Baseline parameters were measured under LF dialyzers and repeated at 2nd week and 6th month after switching to MCO dialyzers. Fat tissues were measured with a skinfold caliper and mid-upper arm circumference. Muscle thickness and strength parameters were measured with ultrasound and handgrip tests.

RESULTS

Median skinfold thickness showed a statistically significant increase in the second week of HD with MCO dialyzers [15 mm (10, 17) to 16 mm (13.3, 19.8), p = 0.04] and remained similar in the 6th month (p = 0.08). There was a gradual increase in median mid-upper arm circumference with a significant increase in the 6th month [28 (27, 29.5), 28.5 cm (27, 30), and 30.6 cm (26.7, 32), respectively, p = 0.03]. Significant increases were detected in the measurements of all four abdominal muscle groups (p = 0.03 for rectus abdominis and external oblique; p = 0.002 for internal oblique and transversus abdominis) in the 2nd week of MCO dialyzers and remained similar in the 6th month. Median RF and GCM thicknesses also significantly increased in the 2nd week (p = 0.001 and p < 0.001, respectively). The thicknesses of the external oblique, internal oblique, transversus abdominis, and rectus femoris muscles showed no significant differences in the 6th month. We also observed significant increases in the median GCM fibril length and GCM fibril pennation (p = 0.01 and p = 0.008, respectively) in the 2nd week, which also remained similar in the 6th month. The handgrip strength test showed a gradual increase at each time point without statistical significance.

CONCLUSION

MCO dialyzers provide increased fat and muscle mass, which might be due to their better clearance of uremic toxins compared to low-flux dialyzers. This study serves as a hypothesis-generating investigation; larger randomized controlled trials are required to validate the hypothesis.

Breast Cancer Risk and Management in the Endocrine Clinic: A Comprehensive Review

OBJECTIVE

This review seeks to provide endocrine clinicians with a comprehensive analysis of breast cancer risk, diagnostic modalities and management strategies in women with endocrine disorders, with particular emphasis on the influence of metabolic factors such as diabetes and obesity, and the role of Menopausal Hormone Therapy (MHT).

DESIGN

The review examines a spectrum of endocrine disorders commonly encountered in clinical practice, including Multiple Endocrine Neoplasia Types 1 (MEN1), 2 (MEN2) and 4 (MEN4), Von Hippel-Lindau syndrome (VHL), Pheochromocytoma and Paraganglioma (PPGL), Acromegaly, Hyperprolactinaemia, Polycystic Ovary Syndrome (PCOS), Congenital Adrenal Hyperplasia (CAH), Turner Syndrome, alongside metabolic conditions such as diabetes and obesity and the effects of MHT. The review critically appraises each disorder's association with breast cancer risk, screening implications and therapeutic management.

PATIENTS

This analysis focuses on women with the aforementioned endocrine and metabolic disorders, assessing their specific breast cancer risk profiles, informed by the latest clinical evidence and molecular insights.

MEASUREMENTS

The review comprehensively evaluates current evidence-based approaches to screening, diagnostic accuracy and treatment in this patient cohort. Emphasis is placed on the metabolic derangements, hormonal influences and genetic predispositions that modulate breast cancer risk, providing disorder-specific recommendations for individualised care.

RESULTS

The findings indicate a significantly elevated breast cancer risk in patients with MEN1, necessitating early initiation of MRI screening by age 40. In MEN2, emerging evidence suggests that combining RET inhibitors with endocrine therapy may yield clinical benefits, although further research is needed to validate this approach. The breast cancer risk associated with MEN4 and VHL syndromes, while documented, remains less well-characterised, requiring further investigation. Diabetes and obesity are confirmed as major modifiable risk factors, particularly in postmenopausal women, where hyperinsulinemia and metabolic dysfunction contribute to increased incidence and poorer outcomes, notably in triple-negative breast cancer (TNBC). The role of MHT, particularly combined oestrogen-progestogen therapy, is strongly associated with increased breast cancer risk, particularly for hormone receptor-positive malignancies, necessitating cautious use and personalised treatment planning. In contrast, oestrogen-only MHT appears to confer a reduced risk in women post-hysterectomy. For patients with PCOS, CAH and Turner Syndrome, while definitive evidence of elevated breast cancer risk is lacking, individualised screening strategies and careful hormone therapy management remain essential due to the complex interplay of hormonal and metabolic factors.

CONCLUSIONS

The review highlights the need for personalised breast cancer screening and management protocols in women with endocrine and metabolic disorders. For high-risk groups such as MEN1 patients, early initiation of MRI screening is warranted. In women with diabetes and obesity, targeted interventions addressing hyperinsulinemia and metabolic dysfunction are critical to mitigating their increased cancer risk. The association between MHT and breast cancer underscores the importance of individualised risk stratification in hormone therapy administration, particularly in women with predisposing genetic or endocrine conditions. Enhanced surveillance tailored to the unique risk profiles of endocrine disorder patients will facilitate early detection and improve clinical outcomes. However, further large-scale studies are necessary to refine these associations and develop robust, evidence-based guidelines.

TRIM32 regulates insulin sensitivity by controlling insulin receptor degradation in the liver

Impaired insulin receptor signaling is strongly linked to obesity-related metabolic conditions like non-alcoholic fatty liver disease (NAFLD) and Type 2 diabetes (T2DM). However, the exact mechanisms behind impaired insulin receptor (INSR) signaling in obesity induced by a high-fat diet remain elusive. In this study, we identify an E3 ubiquitin ligase, tripartite motif-containing protein 32 (TRIM32), as a key regulator of hepatic insulin signaling that targets the insulin receptor (INSR) for ubiquitination and proteasomal degradation in high-fat diet (HFD) mice. HFD induces the nuclear translocation of SREBP-1c (Sterol Regulatory Element-Binding Protein 1c), resulting in increased expression of TRIM32 in hepatocytes. TRIM32 ubiquitylates INSR and facilitates its proteasomal degradation, leading to severe insulin resistance and fat accumulation within the liver of high-fat diet induced obese (DIO) mice. Conversely, liver-specific knockdown of TRIM32 enhances INSR expression and hepatic insulin sensitivity. Reduced AMPK signaling and phosphorylation of SREBP-1c at S372 in high-fat DIO mice promotes the nuclear translocation of SREBP-1c, leading to increased TRIM32 expression. In conclusion, our results demonstrate that TRIM32 promotes diet-induced hepatic insulin resistance by targeting the INSR to degradation.

Targeting endoplasmic reticulum stress as a potential therapeutic strategy for diabetic cardiomyopathy

Endoplasmic reticulum (ER) is an essential organelle involved in vesicular transport, calcium handling, protein synthesis and folding, and lipid biosynthesis and metabolism. ER stress occurs when ER homeostasis is disrupted by the accumulation of unfolded and/or misfolded proteins in the ER lumen. Adaptive pathways of the unfolded protein response (UPR) are activated to maintain ER homeostasis. In obesity and type 2 diabetes mellitus (T2DM), accumulating data indicate that persistent ER stress due to maladaptive UPR interacts with insulin/leptin signaling, which may be the potential and central mechanistic link between obesity-/T2DM-induced metabolic dysregulation (chronic hyperglycemia, dyslipidemia and lipotoxicity in cardiomyocytes), insulin/leptin resistance and the development of diabetic cardiomyopathy (DiabCM). Meanwhile, these pathological conditions further exacerbate ER stress. However, their interrelationships and the underlying molecular mechanisms are not fully understood. A deeper understanding of ER stress-mediated pathways in DiabCM is needed to develop novel therapeutic strategies. The aim of this review is to discuss the crosstalk between ER stress and leptin/insulin signaling and their involvement in the development of DiabCM focusing on mitochondria-associated ER membranes and chronic inflammation. We also present the current direction of drug development and important considerations for translational research into targeting ER stress for the treatment of DiabCM.

SOCS3 Methylation Partially Mediated the Association of Exposure to Triclosan but Not Triclocarban with Type 2 Diabetes Mellitus: A Case-Control Study

This study aimed to evaluate the association of TCs (triclosan (TCS) and triclocarban) exposure with T2DM and glucose metabolism-related indicators and the mediating effect of SOCS3 methylation on their associations. A total of 956 participants (330 T2DM and 626 controls) were included in this case-control study. Logistic regression and generalized linear models were used to assess the effect of TCs on T2DM and glucose metabolism-related indicators. The dose-response relationship between TCs and T2DM was analyzed by restricted cubic spline. Finally, after evaluating the association between TCs and SOCS3 methylation levels, the mediating effect of SOCS3 methylation on the TC-associated T2DM was estimated. Each 1-unit increase in TCS levels was associated with a 13.2% increase in the risk of T2DM (OR = 1.132, 95% CI: 1.062, 1.207). A linear dose-response relationship was found between TCS and T2DM. TCS was negatively associated with Chr17:76356190 methylation. Moreover, mediation analysis revealed that Chr17:76356190 methylation mediated 14.54% of the relationship between TCS exposure and T2DM. Exposure to TCS was associated with a higher prevalence of T2DM. SOCS3 methylation partially mediated the association of TCS with T2DM. Our findings may provide new insights into the treatment of T2DM, and the study of the biological mechanisms of T2DM.

Jiao-tai-wan and its effective component-coptisine alleviate cognitive impairment in db/db mice through the JAK2/STAT3 signaling pathway

BACKGROUND

Cognitive impairment (CI) is now well-accepted as a complication and comorbidity of diabetes mellitus (DM), becoming a serious medical and social problem. Jiao-tai-wan (JTW), one of noted traditional Chinese medicine (TCM), showed dual therapeutic effects on DM and CI. Nevertheless, the potential mechanism is unclear.

PURPOSE

This study sought to investigate the mechanism how JTW protected against DM and CI and screen the active component in JTW.

METHODS

Db/db mice were used as mouse models. Mice were treated by gavage with 0.9 % saline (0.1 mL/10g/d), low dose of JTW (2.4 g/kg/d) or high dose of JTW (4.8 g/kg/d) for 8 weeks separately. To access the effects of JTW, the levels of OGTT, HOMA-IR, blood lipids, inflammatory cytokines in serum and hippocampus were measured, behavioral tests were conducted, and histopathological changes were observed. The mechanism exploration was performed via network pharmacology, RT-qPCR, western blot, and immunofluorescence staining (IF). The impact and mechanism of coptisine in vitro were investigated using BV2 cells induced by LPS as cellular models. In vitro experiments were conducted in two parts. The first part comprised four groups: Control group, LPS group, LPS+LCOP group and LPS+HCOP group. The second part consisted of four groups: Control group, LPS group, LPS+HCOP group, and LPS+ Fed group. The western blot and RT-qPCR methods were used to examine the changes in biomarkers of the JAK2/STAT3 signaling pathways in BV2 cells.

RESULTS

The results demonstrated that JTW could improve OGTT and HOMA-IR, reduce the serum levels of LDL-C, HDL-C, TG, and TC, restore neuronal dysfunction and synaptic plasticity, and decrease the deposition of Aβ in the hippocampus. The findings from ELISA, IF, and RT-qPCR revealed that JTW could alleviate microglial activation and inflammatory status in vivo and coptisine could play the same role in vitro. Moreover, the changes of the JAK2/STAT3 signaling pathway in LPS-induced BV2 cells or hippocampus of db/db mice were distinctly reversed by coptisine or JTW, respectively.

CONCLUSION

Our study suggested that JTW and its effective component coptisine could alleviate diabetes mellitus-related cognitive impairment, closely linked to the JAK2/STAT3 signaling pathway.

Exploring the glycation association with dyslipidaemia: Novel approach for diabetic nephropathy

The transcription factor known as sterol regulatory element-binding protein (SREBP) and the glycation pathways, specifically the formation of Advanced Glycation End Products (AGEs), have a significant and deleterious impact on the kidney. They alter renal lipid metabolism and promote glomerulosclerosis, mesangial cell expansion, tubulointerstitial fibrosis, and inflammation, leading to diabetic nephropathy (DN) progression. Although several pieces of scientific evidence are reported for potential causes of glycation and lipotoxicity in DN, the underlying mechanism of renal lipid accumulation still needs to be fully understood. We provide a rationalized view on how AGEs exert multiple effects that cause SREBP activation and inflammation, contributing to DN through Receptor for AGEs (RAGE) signaling, AGE-R1-dependent downregulation of Sirtuin 1 (SIRT-1), and increased SREBP Cleavage Activating Protein (SCAP) glycosylation. This review emphasizes the association between glycation and the SREBP pathway and how it affects the onset of DN associated with obesity. Finally, we discuss the correlation of glycation and the SREBP pathway with insulin resistance (IR), oxidative stress, endoplasmic reticulum stress, inflammation, and existing and emerging therapeutic approaches toward better controlling obesity-related DN.

Adipose tissue senescence: Biological changes, hallmarks and therapeutic approaches

Adipose tissue (AT), the largest energy storage reservoir and endocrine organ, plays a crucial role in regulating systemic energy metabolism. As one of the most vulnerable tissues during aging, the plasticity of AT is impaired. With age, AT undergoes redistribution, characterized by expansion of visceral adipose tissue (VAT) and reduction of peripheral subcutaneous adipose tissue (SAT). Additionally, age-related changes in AT include reduced adipogenesis of white adipocytes, decreased proliferation and differentiation capacity of mesenchymal stromal/stem cells (MSCs), diminished thermogenic capacity in brown/beige adipocytes, and dysregulation of immune cells. Specific and sensitive hallmarks enable the monitoring and evaluation of the biological changes associated with aging. In this study, we have innovatively proposed seven characteristic hallmarks of AT senescence, including telomere attrition, epigenetic alterations, genomic instability, mitochondrial dysfunction, disabled macroautophagy, cellular senescence, and chronic inflammation, which are intricately interconnected and mutually regulated. Finally, we discussed anti-aging strategies targeting AT, offering insights into mitigating or delaying metabolic disturbances caused by AT senescence.

Exploring the mechanism of Jinlida granules against type 2 diabetes mellitus by an integrative pharmacology strategy

Jinlida granule (JLD) is a Traditional Chinese Medicine (TCM) formula used for the treatment of type 2 diabetes mellitus (T2DM). However, the mechanism of JLD treatment for T2DM is not fully revealed. In this study, we explored the mechanism of JLD against T2DM by an integrative pharmacology strategy. Active components and corresponding targets were retrieved from Traditional Chinese Medicine System Pharmacology (TCMSP), SwissADME and Bioinformatics Analysis Tool for Molecular Mechanisms of Traditional Chinese Medicine Database (BATMAN-TCM) database. T2DM-related targets were obtained from Drugbank and Genecards databases. The protein-protein interaction (PPI) network was constructed and analyzed with STRING (Search Toll for the Retrieval of Interacting Genes/proteins) and Cytoscape to get the key targets. Then, Gene Ontology (GO) and Kyoto Encyclopedia of Gene and Genomes (KEGG) enrichment analyses were performed with the Database for Annotation, Visualization and Integrated Discovery (DAVID). Lastly, the binding capacities and reliability between potential active components and the targets were verified with molecular docking and molecular dynamics simulation. In total, 185 active components and 337 targets of JLD were obtained. 317 targets overlapped with T2DM-related targets. RAC-alpha serine/threonine-protein kinase (AKT1), tumor necrosis factor (TNF), interleukin-6 (IL-6), cellular tumor antigen p53 (TP53), prostaglandin G/H synthase 2 (PTGS2), Caspase-3 (CASP3) and signal transducer and activator of transcription 3 (STAT3) were identified as seven key targets by the topological analysis of the PPI network. GO and KEGG enrichment analyses showed that the effects were primarily associated with gene expression, signal transduction, apoptosis and inflammation. The pathways were mainly enriched in PI3K-AKT signaling pathway and AGE-RAGE signaling pathway in diabetic complications. Molecular docking and molecular dynamics simulation verified the good binding affinity between the key components and targets. The predicted results may provide a theoretical basis for drug screening of JLD and a new insight for the therapeutic effect of JLD on T2DM.

The serine phosphorylations in the IRS-1 PIR domain abrogate IRS-1 and IR interaction

Serine phosphorylations on insulin receptor substrate 1 (IRS-1) by diverse kinases aoccur widely during obesity-, stress-, and inflammation-induced conditions in models of insulin resistance and type 2 diabetes. In this study, we define a region within the human IRS-1, which is directly C-terminal to the PTB domain encompassing numerous serine phosphorylation sites including Ser307 (mouse Ser302) and Ser312 (mouse 307) creating a phosphorylation insulin resistance (PIR) domain. We demonstrate that the IRS-1 PTB-PIR with its unphosphorylated serine residues interacts with the insulin receptor (IR) but loses the IR-binding when they are phosphorylated. Surface plasmon resonance studies further confirm that the PTB-PIR binds stronger to IR than just the PTB domain, and that phosphorylations at Ser307, Ser312, Ser315, and Ser323 within the PIR domain result in abrogating the binding. Insulin-responsive cells containing the mutant IRS-1 with all these four serines changed into glutamates to mimic phosphorylations show decreased levels of phosphorylations in IR, IRS-1, and AKT compared to the wild-type IRS-1. Hydrogen-deuterium exchange mass spectrometry experiments indicating the PIR domain interacting with the N-terminal lobe and the hinge regions of the IR kinase domain further suggest the possibility that the IRS-1 PIR domain protects the IR from the PTP1B-mediated dephosphorylation.

Endotoxin-induced alterations of adipose tissue function: a pathway to bovine metabolic stress

During the periparturient period, dairy cows exhibit negative energy balance due to limited appetite and increased energy requirements for lactogenesis. The delicate equilibrium between energy availability and expenditure puts cows in a state of metabolic stress characterized by excessive lipolysis in white adipose tissues (AT), increased production of reactive oxygen species, and immune cell dysfunction. Metabolic stress, especially in AT, increases the risk for metabolic and inflammatory diseases. Around parturition, cows are also susceptible to endotoxemia. Bacterial-derived toxins cause endotoxemia by promoting inflammatory processes and immune cell infiltration in different organs and systems while impacting metabolic function by altering lipolysis, mitochondrial activity, and insulin sensitivity. In dairy cows, endotoxins enter the bloodstream after overcoming the defense mechanisms of the epithelial barriers, particularly during common periparturient conditions such as mastitis, metritis, and pneumonia, or after abrupt changes in the gut microbiome. In the bovine AT, endotoxins induce a pro-inflammatory response and stimulate lipolysis in AT, leading to the release of free fatty acids into the bloodstream. When excessive and protracted, endotoxin-induced lipolysis can impair adipocyte's insulin signaling pathways and lipid synthesis. Endotoxin exposure can also induce oxidative stress in AT through the production of reactive oxygen species by inflammatory cells and other cellular components. This review provides insights into endotoxins' impact on AT function, highlighting the gaps in our knowledge of the mechanisms underlying AT dysfunction, its connection with periparturient cows' disease risk, and the need to develop effective interventions to prevent and treat endotoxemia-related inflammatory conditions in dairy cattle.

Silencing ANGPTL8 reduces mouse preadipocyte differentiation and insulin signaling

ANGPTL8, expressed mainly in the liver and adipose tissue, regulates the activity of lipoprotein lipase (LPL) present in the extracellular space and triglyceride (TG) metabolism through its interaction with ANGPTL3 and ANGPTL4. Whether intracellular ANGPTL8 can also exert effects in tissues where it is expressed is uncertain. ANGPTL8 expression was low in preadipocytes and much increased during differentiation. To better understand the role of intracellular ANGPTL8 in adipocytes and assess whether it may play a role in adipocyte differentiation, we knocked down its expression in normal mouse subcutaneous preadipocytes. ANGPTL8 knockdown reduced adipocyte differentiation, cellular TG accumulation and also isoproterenol-stimulated lipolysis at day 7 of differentiation. RNA-Seq analysis of ANGPTL8 siRNA or control siRNA transfected SC preadipocytes on days 0, 2, 4 and 7 of differentiation showed that ANGPTL8 knockdown impeded the early (day 2) expression of adipogenic and insulin signaling genes, PPARγ, as well as genes related to extracellular matrix and NF-κB signaling. Insulin mediated Akt phosphorylation was reduced at an early stage during adipocyte differentiation. This study based on normal primary cells shows that ANGPTL8 has intracellular actions in addition to effects in the extracellular space, like modulating LPL activity. Preadipocyte ANGPTL8 expression modulates their differentiation possibly via changes in insulin signaling gene expression.

Discovering therapeutic possibilities for polycystic ovary syndrome by targeting XIST and its associated ceRNA network through the analysis of transcriptome data

Long non-coding RNA (lncRNA) regulates many physiological processes by acting as competitive endogenous RNA (ceRNA). The dysregulation of lncRNA X-inactive specific transcript (XIST) has been shown in various human disorders. However, its role in the pathogenesis of polycystic ovary syndrome (PCOS) is yet to be explored. This study aimed to explore the underlying mechanism of XIST in the pathogenesis of PCOS, specifically through dataset functional analysis. GEO PCOS datasets including RNA-seq, microarray, and miRNA-seq in granulosa cells (GCs) and blood, were examined and comprehensively analyzed. Enrichment analysis, ROC curve constructions, lncRNA-miRNA-mRNA interaction network analyses, and qRT-PCR validation were performed followed by a series of drug signature screenings. Our results revealed significant dysregulation in the expression of 1131 mRNAs, 30 miRNAs, and XIST in GCs of PCOS patients compared to healthy individuals. Of the120 XIST-correlated upregulated genes, 25 were enriched in inflammation-related pathways. Additionally, 5 miRNAs were identified as negative regulators of XIST-correlated genes. Accordingly, a ceRNA network containing XIST-miRNAs-mRNAs interactions was constructed. Furthermore, 6 genes, including AQP9, ETS2, PLAU, PLEK, SOCS3, and TNFRSF1B served as both GCs and blood-based biomarkers. By analyzing the number of interactions among XIST, miRNAs, and mRNAs, we pinpointed ETS2 as the pivotal gene within the ceRNA network. Our findings reveal a novel XIST- hsa-miR-146a-5p, hsa-miR-144-3p, and hsa-miR-1271-5p-ETS2 axis that comprehensively elucidates the XIST-associated mechanism underlying PCOS onset. qRT-PCR analysis further confirmed the, overexpression of both XIST and ETS2 . Furthermore, our results demonstrated that XIST and ETS2 were correlated with some assisted reproductive technologies outcomes. Finally, we identified two novel compounds including, methotrexate/folate and threonine using drug-gene interaction databases for PCOS management. These findings provide novel insights into the molecular etiology, diagnosis, and potential therapeutic interventions for PCOS.

Structural abnormality of hepatic glycogen in rat liver with diethylnitrosamine-induced carcinogenic injury

Growing evidence confirms associations between glycogen metabolic re-wiring and the development of liver cancer. Previous studies showed that glycogen structure changes abnormally in liver diseases such as cystic fibrosis, diabetes, etc. However, few studies focus on glycogen molecular structural characteristics during liver cancer development, which is worthy of further exploration. In this study, a rat model with carcinogenic liver injury induced by diethylnitrosamine (DEN) was successfully constructed, and hepatic glycogen structure was characterized. Compared with glycogen structure in the healthy rat liver, glycogen chain length distribution (CLD) shifts towards a short region. In contrast, glycogen particles were mainly present in small-sized β particles in DEN-damaged carcinogenic rat liver. Comparative transcriptomic analysis revealed significant expression changes of genes and pathways involved in carcinogenic liver injury. A combination of transcriptomic analysis, RT-qPCR, and western blot showed that the two genes, Gsy1 encoding glycogen synthase and Gbe1 encoding glycogen branching enzyme, were significantly altered and might be responsible for the structural abnormality of hepatic glycogen in carcinogenic liver injury. Taken together, this study confirmed that carcinogenic liver injury led to structural abnormality of hepatic glycogen, which provided clues to the future development of novel drug targets for potential therapeutics of carcinogenic liver injury.

SOCS1 expression in cancer cells: potential roles in promoting antitumor immunity

Suppressor of cytokine signaling 1 (SOCS1) is a potent regulator immune cell responses and a proven tumor suppressor. Inhibition of SOCS1 in T cells can boost antitumor immunity, whereas its loss in tumor cells increases tumor aggressivity. Investigations into the tumor suppression mechanisms so far focused on tumor cell-intrinsic functions of SOCS1. However, it is possible that SOCS1 expression in tumor cells also regulate antitumor immune responses in a cell-extrinsic manner via direct and indirect mechanisms. Here, we discuss the evidence supporting the latter, and its implications for antitumor immunity.

The interplay between obesity, immunosenescence, and insulin resistance

Obesity, which is the accumulation of fat in adipose tissue, has adverse impacts on human health. Obesity-related metabolic dysregulation has similarities to the metabolic alterations observed in aging. It has been shown that the adipocytes of obese individuals undergo cellular aging, known as senescence. Senescence can be transmitted to other normal cells through a series of chemical factors referred to as the senescence-associated secretory phenotype (SASP). Most of these factors are pro-inflammatory compounds. The immune system removes these senescent T-cells, but immunosenescence, which is the senescence of immune cells, disrupts the clearance of senescent T-cells. Immunosenescence occurs as a result of aging or indirectly through transmission from senescent tissues. The significant occurrence of senescence in obesity is expected to cause immunosenescence and impairs the immune response to resolve inflammation. The sustained and chronic inflammation disrupts insulin's metabolic actions in metabolic tissues. Therefore, this review focuses on the role of senescent adipocyte cells in obesity-associated immunosenescence and subsequent metabolic dysregulation. Moreover, the article suggests novel therapeutic approaches to improve metabolic syndrome by targeting senescent T-cells or using senotherapeutics.

The Role of Obesity in Type 2 Diabetes Mellitus-An Overview

Obesity or excessive weight gain is identified as the most important and significant risk factor in the development and progression of type 2 diabetes mellitus (DM) in all age groups. It has reached pandemic dimensions, making the treatment of obesity crucial in the prevention and management of type 2 DM worldwide. Multiple clinical studies have demonstrated that moderate and sustained weight loss can improve blood glucose levels, insulin action and reduce the need for diabetic medications. A combined approach of diet, exercise and lifestyle modifications can successfully reduce obesity and subsequently ameliorate the ill effects and deadly complications of DM. This approach also helps largely in the prevention, control and remission of DM. Obesity and DM are chronic diseases that are increasing globally, requiring new approaches to manage and prevent diabetes in obese individuals. Therefore, it is essential to understand the mechanistic link between the two and design a comprehensive approach to increase life expectancy and improve the quality of life in patients with type 2 DM and obesity. This literature review provides explicit information on the clinical definitions of obesity and type 2 DM, the incidence and prevalence of type 2 DM in obese individuals, the indispensable role of obesity in the pathophysiology of type 2 DM and their mechanistic link. It also discusses clinical studies and outlines the recent management approaches for the treatment of these associated conditions. Additionally, in vivo studies on obesity and type 2 DM are discussed here as they pave the way for more rigorous development of therapeutic approaches.

Pericyte Control of Gene Expression in the Blood-Brain Barrier Endothelium: Implications for Alzheimer's Disease

Background

A strong body of evidence suggests that cerebrovascular pathologies augment the onset and progression of Alzheimer's disease (AD). One distinctive aspect of this cerebrovascular dysfunction is the degeneration of brain pericytes-often overlooked supporting cells of blood-brain barrier endothelium.

Objective

The current study investigates the influence of pericytes on gene and protein expressions in the blood-brain barrier endothelium, which is expected to facilitate the identification of pathophysiological pathways that are triggered by pericyte loss and lead to blood-brain barrier dysfunction in AD.

Methods

Bioinformatics analysis was conducted on the RNA-Seq expression counts matrix (GSE144474), which compared solo-cultured human blood-brain barrier endothelial cells against endothelial cells co-cultured with human brain pericytes in a non-contact model. We constructed a similar cell culture model to verify protein expression using western blots.

Results

The insulin resistance and ferroptosis pathways were found to be enriched. Western blots of the insulin receptor and heme oxygenase expressions were consistent with those observed in RNA-Seq data. Additionally, we observed more than 5-fold upregulation of several genes associated with neuroprotection, including insulin-like growth factor 2 and brain-derived neurotrophic factor.

Conclusions

Results suggest that pericyte influence on blood-brain barrier endothelial gene expression confers protection from insulin resistance, iron accumulation, oxidative stress, and amyloid deposition. Since these are conditions associated with AD pathophysiology, they imply mechanisms by which pericyte degeneration could contribute to disease progression.

LncRNA MEG3: Targeting the Molecular Mechanisms and Pathogenic causes of Metabolic Diseases

BACKGROUND

Non-coding RNA is a type of RNA that does not encode proteins, distributed among rRNA, tRNA, snRNA, snoRNA, microRNA and other RNAs with identified functions, where the Long non-coding RNA (lncRNA) displays a nucleotide length over 200. LncRNAs enable multiple biological processes in the human body, including cancer cell invasion and metastasis, apoptosis, cell autophagy, inflammation, etc. Recently, a growing body of studies has demonstrated the association of lncRNAs with obesity and obesity-induced insulin resistance and NAFLD, where MEG3 is related to glucose metabolism, such as insulin resistance. In addition, MEG3 has been demonstrated in the pathological processes of various cancers, such as mediating inflammation, cardiovascular disease, liver disease and other metabolic diseases.

OBJECTIVE

To explore the regulatory role of lncRNA MEG3 in metabolic diseases. It provides new ideas for clinical treatment or experimental research.

METHODS

In this paper, in order to obtain enough data, we integrate and analyze the data in the PubMed database.

RESULTS

LncRNA MEG3 can regulate many metabolic diseases, such as insulin resistance, NAFLD, inflammation and so on.

CONCLUSION

LncRNA MEG3 has a regulatory role in a variety of metabolic diseases, which are currently difficult to be completely cured, and MEG3 is a potential target for the treatment of these diseases. Here, we review the role of lncRNA MEG3 in mechanisms of action and biological functions in human metabolic diseases.

Engineering the IL-4/IL-13 axis for targeted immune modulation

The structurally and functionally related interleukin-4 (IL-4) and IL-13 cytokines play pivotal roles in shaping immune activity. The IL-4/IL-13 axis is best known for its critical role in T helper 2 (Th2) cell-mediated Type 2 inflammation, which protects the host from large multicellular pathogens, such as parasitic helminth worms, and regulates immune responses to allergens. In addition, IL-4 and IL-13 stimulate a wide range of innate and adaptive immune cells, as well as non-hematopoietic cells, to coordinate various functions, including immune regulation, antibody production, and fibrosis. Due to its importance for a broad spectrum of physiological activities, the IL-4/IL-13 network has been targeted through a variety of molecular engineering and synthetic biology approaches to modulate immune behavior and develop novel therapeutics. Here, we review ongoing efforts to manipulate the IL-4/IL-13 axis, including cytokine engineering strategies, formulation of fusion proteins, antagonist development, cell engineering approaches, and biosensor design. We discuss how these strategies have been employed to dissect IL-4 and IL-13 pathways, as well as to discover new immunotherapies targeting allergy, autoimmune diseases, and cancer. Looking ahead, emerging bioengineering tools promise to continue advancing fundamental understanding of IL-4/IL-13 biology and enabling researchers to exploit these insights to develop effective interventions.

Effects of dietary adjustment of n-3:n-6 fatty-acid ratio to 1:2 on anti-inflammatory and insulin-signaling pathways in ovariectomized mice with high fat diet-induced obesity

Estrogen deficiency increases the secretion of inflammatory mediators and can lead to obesity. Consequently, estrogen deficiency can cause metabolic syndrome, particularly insulin resistance during menopause. Both fish oil and perilla oil contain n-3 fatty acids, which may regulate several inflammatory cytokines. Additionally, adjusting the dietary n-3:n-6 fatty-acid ratio to 1:2 may help treat or prevent chronic diseases. Therefore, we investigated the effect of anti-inflammatory and insulin-signaling pathways, not solely in relation to the (n-3:n-6 fatty-acid ratio at 1:2), but also considering the origin of n-3 fatty acids found in fish oil and perilla oil, in a mouse model of estrogen deficiency induced by ovariectomy and obesity induced by a high-fat diet (HFD). Female C57BL/6J mice were divided into five groups: sham mice on a normal diet; ovariectomized (OVX) mice on a normal diet (OC); OVX mice on a HFD plus lard oil (OL), fish oil (OF), or perilla oil (OP). The dietary n-3:n-6 ratio in the OF and OP groups was adjusted to 1:2. The results showed OF group exhibited significantly lower abdominal adipose tissue weight, fewer liver lipid droplets, and smaller uterine adipocytes, compared with the OL group. Compared with the OL group, the OF and OP groups exhibited higher oral glucose tolerance and lower serum alanine aminotransferase activity, triacylglycerol levels, and total cholesterol levels. Hepatic JAK2, STAT3, and SOCS3 mRNA expression and p-NF-κB p65 and IL-6 levels were significantly lower in the OF and OP groups than in the OL group. Only the OF group exhibited an increase in PI3K and Akt mRNA expression, decrease in GLUT2 mRNA expression, and considerable elevation of p-Akt. Both fish and perilla oil reduced inflammatory signaling markers. However, only fish oil improved insulin signaling (PI3K, Akt, and GLUT2). Our data suggest that fish oil can alleviate insulin signaling through activating the PI3K-Akt-GLUT2 cascade signaling pathway.

The effect of hormones insulin and glucagon on ubiquitin modifications elucidated by proteomics in liver cells

AIMS

Insulin action is intertwined with changing levels of glucose and counter-regulatory hormone glucagon. While insulin lowers blood sugar level, glucagon raises it by promoting the breakdown of the stored glycogen in liver and releases glucose into the bloodstream. The hormones insulin and glucagon are key in the pathogenesis of type 2 diabetes (T2D). Insulin resistance is a primary predisposing factor for diabetes. Phosphorylation of insulin signaling molecules is altered in the insulin-resistant state. However, ubiquitin (Ub) modifications in insulin-resistant state are relatively understudied. To dissect the underlying mechanisms, we performed a proteomics study on hepatoma cells to study the regulation of ubiquitination by insulin and glucagon.

MATERIALS AND METHODS

We performed western blotting, immunoprecipitations, and affinity pull down using tandem Ub binding entities (TUBE) reagents on hepatoma cells treated with insulin or glucagon. Next, we performed MS/MS analysis on Ub-linkage specific affinity pull down samples. Gene ontology analysis and protein-protein interaction network analysis was performed using DAVID GO and STRING db, respectively.

KEY FINDINGS

The ubiquitination pattern of total Ub, K48-linked Ub, and K63-linked Ub was altered with the treatment of hormones insulin and glucagon. Ubiquitination in immunoprecipitated samples showed enrichment with total Ub and K48-linked Ub but not with K63-linked Ub. Ubiquitination by treatment with hormones mainly enriched key signaling pathways MAPK, Akt, oxidative stress etc. SIGNIFICANCE: Our study identified key altered proteins and signal transduction pathways which aids in understanding the mechanisms of hormonal action on ubiquitination and identify new therapeutic targets for T2D.

Phosphorylation of insulin receptor substrates (IRS-1 and IRS-2) is attenuated following cecal ligation and puncture in mice

BACKGROUND

Sepsis is characterized as an insulin resistant state. However, the effects of sepsis on insulin's signal transduction pathway are unknown. The molecular activity driving insulin signaling is controlled by tyrosine phosphorylation of the insulin receptor β-subunit (IRβ) and of insulin receptor substrate molecules (IRS) -1 and IRS-2.

HYPOTHESIS

Cecal ligation and puncture (CLP) attenuates IRβ, IRS-1 and IRS-2 phosphorylation.

METHODS

IACUC-approved studies conformed to ARRIVE guidelines. CLP was performed on C57BL/6 mice; separate cohorts received intraperitoneal insulin at baseline (T0) or at 23 or 47 h. post-CLP, 1 h before mice were euthanized. We measured levels of (1) glucose and insulin in serum, (2) IRβ, IRS-1 and IRS-2 in skeletal muscle and liver homogenate and (3) phospho-Irβ (pIRβ) in liver and skeletal muscle, phospho-IRS-1 (pIRS-1) in skeletal muscle and pIRS-2 in liver. Statistical significance was determined using ANOVA with Sidak's post-hoc correction.

RESULTS

CLP did not affect the concentrations of IRβ, IRS-1or IRS-2 in muscle or liver homogenate or of IRS-1 in liver. Muscle IRS-1 concentration at 48 h. post-CLP was higher than at T0. Post-CLP pIRS-1 levels in muscle and pIRβ and pIRS-2 levels in liver were indistinguishable from T0 levels. At 48 h. post-CLP pIRβ levels in muscle were higher than at T0. Following insulin administration, the relative abundance of pIRβ in muscle and liver at T0 and at both post-CLP time points was significantly higher than abundance in untreated controls. In T0 controls, the relative abundance of pIRS-1 in muscle and of pIRS-2 in liver following insulin administration was higher than in untreated mice. However, at both post-CLP time points, the relative abundance of pIRS-1 in muscle and of pIRS-2 in liver following insulin administration was not distinguishable from the abundance in untreated mice at the same time point. Serum glucose concentration was significantly lower than T0 at 24 h., but not 48 h., post-CLP. Glucose concentration was lower following insulin administration to T0 mice but not in post-CLP animals. Serum insulin levels were significantly higher than baseline at both post-CLP time points.

CONCLUSIONS

CLP impaired insulin-induced tyrosine phosphorylation of both IRS-1 in muscle and IRS-2 in liver. These findings suggest that the molecular mechanism underlying CLP-induced insulin resistance involves impaired IRS-1/IRS-2 phosphorylation.

Functional role of skeletal muscle-derived interleukin-6 and its effects on lipid metabolism

The detrimental impact of obesity on human health is increasingly evident with the rise in obesity-related diseases. Skeletal muscle, the crucial organ responsible for energy balance metabolism, plays a significant role as a secretory organ by releasing various myokines. Among these myokines, interleukin 6 (IL-6) is closely associated with skeletal muscle contraction. IL-6 triggers the process of lipolysis by mobilizing energy-storing adipose tissue, thereby providing energy for physical exercise. This phenomenon also elucidates the health benefits of regular exercise. However, skeletal muscle and adipose tissue maintain a constant interaction, both directly and indirectly. Direct interaction occurs through the accumulation of excess fat within skeletal muscle, known as ectopic fat deposition. Indirect interaction takes place when adipose tissue is mobilized to supply the energy for skeletal muscle during exercise. Consequently, maintaining a functional balance between skeletal muscle and adipose tissue becomes paramount in regulating energy metabolism and promoting overall health. IL-6, as a representative cytokine, participates in various inflammatory responses, including non-classical inflammatory responses such as adipogenesis. Skeletal muscle influences adipogenesis through paracrine mechanisms, primarily by secreting IL-6. In this research paper, we aim to review the role of skeletal muscle-derived IL-6 in lipid metabolism and other physiological activities, such as insulin resistance and glucose tolerance. By doing so, we provide valuable insights into the regulatory function of skeletal muscle-derived myokines in lipid metabolism.

Kremen2 drives the progression of non-small cell lung cancer by preventing SOCS3-mediated degradation of EGFR

BACKGROUND

The transmembrane receptor Kremen2 has been reported to participate in the tumorigenesis and metastasis of gastric cancer. However, the role of Kremen2 in non-small cell lung cancer (NSCLC) and the underlying mechanism remain unclear. This study aimed to explore the biological function and regulatory mechanism of Kremen2 in NSCLC.

METHODS

The correlation between Kremen2 expression and NSCLC was assessed by analyzing the public database and clinical tissue samples. Colony formation and EdU assays were performed to examine cell proliferation. Transwell and wound healing assays were used to observe cell migration ability. Tumor-bearing nude mice and metastatic tumor models were used to detect the in vivo tumorigenic and metastatic abilities of the NSCLC cells. An immunohistochemical assay was used to detect the expression of proliferation-related proteins in tissues. Western blot, immunoprecipitation and immunofluorescence were conducted to elucidate the Kremen2 regulatory mechanisms in NSCLC.

RESULTS

Kremen2 was highly expressed in tumor tissues from NSCLC patients and was positively correlated with a poor patient prognosis. Knockout or knockdown of Kremen2 inhibited cell proliferation and migration ability of NSCLC cells. In vivo knockdown of Kremen2 inhibited the tumorigenicity and number of metastatic nodules of NSCLC cells in nude mice. Mechanistically, Kremen2 interacted with suppressor of cytokine signaling 3 (SOCS3) to maintain the epidermal growth factor receptor (EGFR) protein levels by preventing SOCS3-mediated ubiquitination and degradation of EGFR, which, in turn, promoted activation of the PI3K-AKT and JAK2-STAT3 signaling pathways.

CONCLUSIONS

Our study identified Kremen2 as a candidate oncogene in NSCLC and may provide a potential target for NSCLC treatment.

Pharmaceutical SH2 domain-containing protein tyrosine phosphatase 2 inhibition suppresses primary and metastasized liver tumors by provoking hepatic innate immunity

BACKGROUND AND AIMS

SH2 domain-containing protein tyrosine phosphatase 2 (Shp2) is the first identified pro-oncogenic tyrosine phosphatase that acts downstream of receptor tyrosine kinases (RTKs) to promote Ras-extracellular signal-regulated kinase signaling. However, this phosphatase was also shown to be antitumorigenic in HCC. This study is aimed at deciphering paradoxical Shp2 functions and mechanisms in hepatocarcinogenesis and at exploring its value as a pharmaceutical target in HCC therapy.

APPROACHES AND RESULTS

We took both genetic and pharmaceutical approaches to examine the effects of Shp2 inhibition on primary liver cancers driven by various oncogenes and on metastasized liver tumors. We show here that the catalytic activity of Shp2 was essential for relay of oncogenic signals from RTKs in HCC and that chemical inhibition of Shp2 robustly suppressed HCC driven by RTKs. However, in contrast to a tumor-promoting hepatic niche generated by genetically deleting Shp2 in hepatocytes, treatment with a specific Shp2 inhibitor had a tumor-suppressing effect on metastasized liver tumor progression. Mechanistically, the Shp2 inhibitor enhanced antitumor innate immunity by down-regulating inflammatory cytokines, suppressing the chemokine (C-C motif) receptor 5 signaling axis, but up-regulating interferon-β secretion.

CONCLUSIONS

These results unveil complex mechanisms for the tumor-suppressing effect of pharmaceutical Shp2 inhibition in the liver immune environment. We provide a proof of principle for clinical trials with specific Shp2 inhibitors in patients with primary and metastasized liver cancer.

Jiang-Tang-San-Huang pill alleviates type 2 diabetes mellitus through modulating the gut microbiota and bile acids metabolism

BACKGROUND

Jiang-Tang-San-Huang (JTSH) pill, a traditional Chinese medicine (TCM) prescription, has long been applied to clinically treat type 2 diabetes mellitus (T2DM), while the underlying antidiabetic mechanism remains unclarified. Currently, it is believed that the interaction between intestinal microbiota and bile acids (BAs) metabolism mediates host metabolism and promotes T2DM.

PURPOSE

To elucidate the underlying mechanisms of JTSH for treating T2DM with animal models.

METHODS

In this study, male SD rats received high-fat diet (HFD) and streptozotocin (STZ) injection to induce T2DM and were treated with different dosages (0.27, 0.54 and 1.08 g/kg) of JTSH pill for 4 weeks; metformin was given as a positive control. Alterations of gut microbiota and BA profiles in the distal ileum were assessed by 16S ribosomal RNA gene sequencing and ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), respectively. Additionally, we conducted quantitative Real Time-PCR and western blotting to determine the mRNA and protein expression levels of intestinal farnesoid X receptor (FXR), fibroblast growth factor 15 (FGF15), Takeda G-protein-coupled receptor 5 (TGR5) and glucagon-like peptide 1 (GLP-1) as well as hepatic cytochrome P450, family 7, subfamily a, poly-peptide 1 (CYP7A1) and cytochrome P450, family 8, subfamily b, poly-peptide 1 (CYP8B1), which are involved in BAs metabolism and enterohepatic circulation.

RESULTS

Here, the results revealed that JTSH treatment significantly ameliorated hyperglycaemia, insulin resistance (IR), hyperlipidaemia, and pathological changes in the pancreas, liver, kidney and intestine and reduced the serum levels of pro-inflammatory cytokines in T2DM model rats. 16S rRNA sequencing and UPLC-MS/MS showed that JTSH treatment could modulate gut microbiota dysbiosis by preferentially increasing bacteria (e.g., Bacteroides, Lactobacillus, Bifidobacterium) with bile-salt hydrolase (BSH) activity, which might in turn lead to the accumulation of ileal unconjugated BAs (e.g., CDCA, DCA) and further upregulate the intestinal FXR/FGF15 and TGR5/GLP-1 signaling pathways.

CONCLUSION

The study demonstrated that JTSH treatment could alleviate T2DM by modulating the interaction between gut microbiota and BAs metabolism. These findings suggest that JTSH pill may serve as a promising oral therapeutic agent for T2DM.

The pivotal role of JAK/STAT and IRS/PI3K signaling pathways in neurodegenerative diseases: Mechanistic approaches to polyphenols and alkaloids

BACKGROUND

Neurodegenerative diseases (NDDs) are characterized by progressive neuronal dysfunctionality which results in disability and human life-threatening events. In recent decades, NDDs are on the rise. Besides, conventional drugs have not shown potential effectiveness to attenuate the complications of NDDs. So, exploring novel therapeutic agents is an urgent need to combat such disorders. Accordingly, growing evidence indicates that polyphenols and alkaloids are promising natural candidates, possessing several beneficial pharmacological effects against diseases. Considering the complex pathophysiological mechanisms behind NDDs, Janus kinase (JAK), insulin receptor substrate (IRS), phosphoinositide 3-kinase (PI3K), and signal transducer and activator of transcription (STAT) seem to play critical roles during neurodegeneration/neuroregeneration. In this line, modulation of the JAK/STAT and IRS/PI3K signaling pathways and their interconnected mediators by polyphenols/alkaloids could play pivotal roles in combating NDDs, including Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), stroke, aging, multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), depression and other neurological disorders.

PURPOSE

Thus, the present study aimed to investigate the neuroprotective roles of polyphenols/alkaloids as multi-target natural products against NDDs which are critically passing through the modulation of the JAK/STAT and IRS/PI3K signaling pathways.

STUDY DESIGN AND METHODS

A systematic and comprehensive review was performed to highlight the modulatory roles of polyphenols and alkaloids on the JAK/STAT and IRS/PI3K signaling pathways in NDDs, according to the PRISMA guideline, using scholarly electronic databases, including Scopus, PubMed, ScienceDirect, and associated reference lists.

RESULTS

In the present study 141 articles were included from a total of 1267 results. The results showed that phenolic compounds such as curcumin, epigallocatechin-3-gallate, and quercetin, and alkaloids such as berberine could be introduced as new strategies in combating NDDs through JAK/STAT and IRS/PI3K signaling pathways. This is the first systematic review that reveals the correlation between the JAK/STAT and IRS/PI3K axis which is targeted by phytochemicals in NDDs. Hence, this review highlighted promising insights into the neuroprotective potential of polyphenols and alkaloids through the JAK/STAT and IRS/PI3K signaling pathway and interconnected mediators toward neuroprotection.

CONCLUSION

Amongst natural products, phenolic compounds and alkaloids are multi-targeting agents with the most antioxidants and anti-inflammatory effects possessing the potential of combating NDDs with high efficacy and lower toxicity. However, additional reports are needed to prove the efficacy and possible side effects of natural products.

The effect of G0S2 on insulin sensitivity: A proteomic analysis in a G0S2-overexpressed high-fat diet mouse model

BACKGROUND

Previous research has shown a tight relationship between the G0/G1 switch gene 2 (G0S2) and metabolic diseases such as non-alcoholic fatty liver disease (NAFLD) and obesity and diabetes, and insulin resistance has been shown as the major risk factor for both NAFLD and T2DM. However, the mechanisms underlying the relationship between G0S2 and insulin resistance remain incompletely understood. Our study aimed to confirm the effect of G0S2 on insulin resistance, and determine whether the insulin resistance in mice fed a high-fat diet (HFD) results from G0S2 elevation.

METHODS

In this study, we extracted livers from mice that consumed HFD and received tail vein injections of AD-G0S2/Ad-LacZ, and performed a proteomics analysis.

RESULTS

Proteomic analysis revealed that there was a total of 125 differentially expressed proteins (DEPs) (56 increased and 69 decreased proteins) among the identified 3583 proteins. Functional enrichment analysis revealed that four insulin signaling pathway-associated proteins were significantly upregulated and five insulin signaling pathway -associated proteins were significantly downregulated.

CONCLUSION

These findings show that the DEPs, which were associated with insulin resistance, are generally consistent with enhanced insulin resistance in G0S2 overexpression mice. Collectively, this study demonstrates that G0S2 may be a potential target gene for the treatment of obesity, NAFLD, and diabetes.

Chronic kidney disease-induced muscle atrophy: Molecular mechanisms and promising therapies

Chronic kidney disease (CKD) is a high-risk chronic catabolic disease due to its high morbidity and mortality. CKD is accompanied by many complications, leading to a poor quality of life, and serious complications may even threaten the life of CKD patients. Muscle atrophy is a common complication of CKD. Muscle atrophy and sarcopenia in CKD patients have complex pathways that are related to multiple mechanisms and related factors. This review not only discusses the mechanisms by which inflammation, oxidative stress, mitochondrial dysfunction promote CKD-induced muscle atrophy but also explores other CKD-related complications, such as metabolic acidosis, vitamin D deficiency, anorexia, and excess angiotensin II, as well as other related factors that play a role in CKD muscle atrophy, such as insulin resistance, hormones, hemodialysis, uremic toxins, intestinal flora imbalance, and miRNA. We highlight potential treatments and drugs that can effectively treat CKD-induced muscle atrophy in terms of complication treatment, nutritional supplementation, physical exercise, and drug intervention, thereby helping to improve the prognosis and quality of life of CKD patients.

Effects of antidiabetics and exercise therapy on suppressors of cytokine signaling-1, suppressors of cytokine signaling-3, and insulin receptor substrate-1 molecules in diabetes and obesity

OBJECTIVE

Pathological destruction of insulin signaling molecules such as insulin receptor substrate, especially due to the increase in suppressors of cytokine signaling molecules, has been demonstrated in experimental diabetes. The contribution of suppressors of cytokine signaling proteins to the development of insulin resistance and the effects of antidiabetic drugs and exercise on suppressors of cytokine signaling proteins are not clearly known.

METHODS

A total of 48 Wistar albino adult male rats were divided into six groups: control group, obese group with diabetes, obese diabetic rats treated with metformin, obese diabetic rats treated with pioglitazone, obese diabetic rats treated with exenatide, and obese diabetic rats with applied exercise program. Immunohistochemical staining was performed in both the liver and adipose tissue.

RESULTS

There was a statistically significant decrease in suppressors of cytokine signaling-1, a decrease in suppressors of cytokine signaling-3, an increase in insulin receptor substrate-1, and a decrease in immunohistochemical staining in the obese group treated with metformin and exenatide compared to the obese group without treatment in the liver tissue (p<0.05). A statistically significant decrease in immunohistochemical staining of suppressors of cytokine signaling-1 and suppressors of cytokine signaling-3 was found in the obese group receiving exercise therapy compared to the obese group without treatment in visceral adipose tissue (p<0.05). Likewise, no significant immunohistochemistry staining was seen in diabetic obese groups.

CONCLUSION

Metformin or exenatide treatment could prevent the degradation of insulin receptor substrate-1 protein by reducing the effect of suppressors of cytokine signaling-1 and suppressors of cytokine signaling-3 proteins, especially in the liver tissue. In addition, exercise can play a role as a complementary therapy by reducing suppressors of cytokine signaling-1 and suppressors of cytokine signaling-3 proteins in visceral adipose tissue.

Alterations of SOCS1 and SOCS3 transcript levels, but not promoter methylation levels in subcutaneous adipose tissues in obese women

BACKGROUND

Animal model studies suggest that change in the members of the suppressor of the cytokine signaling (SOCS) family (mainly SOCS1 and SOCS3) is linked to the pathogenesis of obesity-related metabolic disorders. Moreover, epigenetic modification is involved in the transcriptional regulation of the SOCS gene family. Here, we aimed to evaluate the mRNA expression as well as gene promoter methylation of SOCS1 and SOCS3 in subcutaneous adipose tissue (SAT) from obese women compared to normal-weight subjects. We also intend to identify the possible association of SOCS1 and SOCS3 transcript levels with metabolic parameters in the context of obesity.

METHODS

This study was conducted on women with obesity (n = 24) [body mass index (BMI) ≥ 30 kg/m ²] and women with normal-weight (n = 22) (BMI < 25 kg/m ²). Transcript levels of SOCS1 and SOCS3 were evaluated by real-time PCR in SAT from all participants. After bisulfite treatment of DNA, methylation-specific PCR was used to assess the putative methylation of 10 CpG sites in the promoter of SOCS1 and 13 CpG sites in SOCS3 in SAT from women with obesity and normal weight.

RESULTS

It was found that unlike SOCS3, which disclosed an elevating expression pattern, the expression level of SOCS1 was lower in the women with obesity as compared with their non-obese counterparts (P-value = 0.03 for SOCS1 transcript level and P-value = 0.011 for SOCS3 transcript level). As for the analysis of promoter methylation, it was found that SOCS1 and SOCS3 methylation were not significantly different between the individuals with obesity and normal weight (P-value = 0.45 and P-value = 0.89). Correlation analysis indicated that the transcript level of SOCS1 mRNA expression had an inverse correlation with BMI, hs-CRP levels, HOMA-IR, and insulin levels. However, the SOCS3 transcript level showed a positive correlation with BMI, waist-to-height ratio, waist circumference, hip circumference, hs-CRP, HOMA-IR, insulin, fasting blood glucose, and total cholesterol. Interestingly, HOMA-IR is the predictor of the transcript level of SOCS1 (β =  - 0.448, P-value = 0.003) and SOCS3 (β = 0.465, P-value = 0.002) in SAT of all participants.

CONCLUSIONS

Our findings point to alterations of SOCS1 and SOCS3 transcript levels, but not promoter methylation levels in subcutaneous adipose tissues from women with obesity. Moreover, mRNA expression of SOCS1 and SOCS3 in SAT was associated with known obesity indices, insulin resistance, and hs-CRP, suggesting the contribution of SOCS1 and SOCS3 in the pathogenesis of obesity-related metabolic abnormalities. However, further studies are required to establish this concept.

The PI3K/Akt Pathway in Meta-Inflammation

Obesity is a global epidemic representing a serious public health burden as it is a major risk factor for the development of cardiovascular disease, stroke and all-cause mortality. Chronic low-grade systemic inflammation, also known as meta-inflammation, is thought to underly obesity's negative health consequences, which include insulin resistance and the development of type 2 diabetes. Meta-inflammation is characterized by the accumulation of immune cells in adipose tissue, a deregulation in the synthesis and release of adipokines and a pronounced increase in the production of proinflammatory factors. In this state, the infiltration of macrophages and their metabolic activation contributes to complex paracrine and autocrine signaling, which sustains a proinflammatory microenvironment. A key signaling pathway mediating the response of macrophages and adipocytes to a microenvironment of excessive nutrients is the phosphoinositide 3-kinase (PI3K)/Akt pathway. This multifaceted network not only transduces metabolic information but also regulates macrophages' intracellular changes, which are responsible for their phenotypic switch towards a more proinflammatory state. In the present review, we discuss how the crosstalk between macrophages and adipocytes contributes to meta-inflammation and provide an overview on the involvement of the PI3K/Akt signaling pathway, and how its impairment contributes to the development of insulin resistance.

REDD1 promotes obesity-induced metabolic dysfunction via atypical NF-κB activation

Regulated in development and DNA damage response 1 (REDD1) expression is upregulated in response to metabolic imbalance and obesity. However, its role in obesity-associated complications is unclear. Here, we demonstrate that the REDD1-NF-κB axis is crucial for metabolic inflammation and dysregulation. Mice lacking Redd1 in the whole body or adipocytes exhibited restrained diet-induced obesity, inflammation, insulin resistance, and hepatic steatosis. Myeloid Redd1-deficient mice showed similar results, without restrained obesity and hepatic steatosis. Redd1-deficient adipose-derived stem cells lost their potential to differentiate into adipocytes; however, REDD1 overexpression stimulated preadipocyte differentiation and proinflammatory cytokine expression through atypical IKK-independent NF-κB activation by sequestering IκBα from the NF-κB/IκBα complex. REDD1 with mutated Lys^219/220Ala, key amino acid residues for IκBα binding, could not stimulate NF-κB activation, adipogenesis, and inflammation in vitro and prevented obesity-related phenotypes in knock-in mice. The REDD1-atypical NF-κB activation axis is a therapeutic target for obesity, meta-inflammation, and metabolic complications.

Hepatic cytokine-inducible SH2-containing protein (CISH) regulates gluconeogenesis via cAMP-responsive element binding protein (CREB)

Impairment of gluconeogenesis is a key factor responsible for hyperglycemia in patients with type 2 diabetes. As an important member of the suppressors of cytokine signaling (SOCS) protein family, many physiological functions of cytokine-inducible SH2-containing protein (CISH) have been described; however, the role of hepatic CISH in gluconeogenesis is poorly understood. In the present study, we observed that hepatic CISH expression was reduced in fasted wild-type (WT) mice. Overexpression of CISH decreased glucose production in mouse primary hepatocytes, while silencing of CISH had the opposite effects. In addition, adenovirus-mediated hepatic CISH overexpression resulted in improved glucose tolerance and decreased gluconeogenesis in WT and leptin receptor-deficient diabetic (db/db) mice. In contrast, adenovirus-mediated hepatic CISH knockdown impaired glucose tolerance and increased gluconeogenesis in WT mice. We also generated liver-specific CISH knockout (LV-CISH KO) mice and discovered that these mice had a similar phenotype in glucose tolerance and gluconeogenesis as mice injected with adenoviruses that knockdown CISH expression. Mechanistically, we found that CISH overexpression decreased and CISH knockdown increased the mRNA and protein levels of glucose-6-phosphatase (G6Pase) and phosphoenolpyruvate carboxykinase 1 (PEPCK), two key enzymes involved in gluconeogenesis, in vitro, and in vivo. Moreover, we discovered that the phosphorylation of cAMP-responsive element binding protein 1 (CREB), a transcription factor of G6pase and Pepck, was required for regulating gluconeogenesis by CISH. Taken together, this study identifies hepatic CISH as an important regulator of gluconeogenesis. Our results also provide important insights into the metabolic functions of the SOCS protein family and the potential targets for the treatment of diabetes.

The Novel Peptide Chm-273s Has Therapeutic Potential for Metabolic Disorders: Evidence from In Vitro Studies and High-Sucrose Diet and High-Fat Diet Rodent Models

The aim of this study was to develop a novel peptide potentially applicable for the treatment of metabolic conditions, such as obesity and type 2 diabetes (T2D). We identified CHM-273S from the list of peptides from milk hydrolysate obtained by HPLC/MS-MS. In vitro analysis of primary murine fibroblasts indicated the potential of CHM-273S to upregulate IRS2 mRNA expression. CHM-273S showed a prominent anorexigenic effect in mice with the induction of a key mechanism of leptin signaling via STAT3 in the hypothalamus as a possible effector. In the animal model of metabolic disease, CHM-273S alleviated glucose intolerance and insulin resistance, and induced phosphorylation of Akt at Ser473 and Thr308 in the hepatocytes of high-sucrose diet-fed rats. In a murine model of T2D, CHM-273S mitigated high-fat diet-induced hyperglycemia and insulin resistance and improved low-grade inflammation by diminishing serum TNFα. Mice treated with chronic CHM-273S had a significant reduction in body weight, with a lower visceral fat pad weight and narrow adipocytes. The effects of the peptide administration were comparable to those of metformin. We show the potential of CHM-273S to alleviate diet-induced metabolic alterations in rodents, substantiating its further development as a therapeutic for obesity, T2D, and other metabolic conditions.

Hyperuricemia contributes to glucose intolerance of hepatic inflammatory macrophages and impairs the insulin signaling pathway via IRS2-proteasome degradation

AIM

Numerous reports have demonstrated the key importance of macrophage-elicited metabolic inflammation in insulin resistance (IR). Our previous studies confirmed that hyperuricemia or high uric acid (HUA) treatment induced an IR state in several peripheral tissues to promote the development of type 2 diabetes mellitus (T2DM). However, the effect of HUA on glucose uptake and the insulin sensitivity of macrophages and its mechanism is unclear.

METHODS

To assess systemic IR, we generated hyperuricemic mice by urate oxidase knockout (UOX-KO). Then, glucose/insulin tolerance, the tissue uptake of 18F-fluorodeoxyglucose, body composition, and energy balance were assessed. Glucose uptake of circulating infiltrated macrophages in the liver was evaluated by glucose transporter type 4 (GLUT-4) staining. Insulin sensitivity and the insulin signaling pathway of macrophages were demonstrated using the 2-NBDG kit, immunoblotting, and immunofluorescence assays. The immunoprecipitation assay and LC-MS analysis were used to determine insulin receptor substrate 2 (IRS2) levels and its interacting protein enrichment under HUA conditions.

RESULTS

Compared to WT mice (10 weeks old), serum uric acid levels were higher in UOX-KO mice (WT, 182.3 ± 5.091 μM versus KO, 421.9 ± 45.47 μM). Hyperuricemic mice with metabolic disorders and systemic IR showed inflammatory macrophage recruitment and increased levels of circulating proinflammatory cytokines. HUA inhibited the nuclear translocation of GLUT-4 in hepatic macrophages, restrained insulin-induced glucose uptake and glucose tolerance, and blocked insulin IRS2/PI3K/AKT signaling. Meanwhile, HUA mediated the IRS2 protein degradation pathway and activated AMPK/mTOR in macrophages. LC-MS analysis showed that ubiquitination degradation could be involved in IRS2 and its interacting proteins to contribute to IR under HUA conditions.

CONCLUSION

The data suggest that HUA-induced glucose intolerance in hepatic macrophages contributed to insulin resistance and impaired the insulin signaling pathway via IRS2-proteasome degradation.

Hepatic interleukin-1 receptor type 1 signalling regulates insulin sensitivity in the early phases of nonalcoholic fatty liver disease

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is associated with hepatic as well as systemic insulin resistance even in the absence of type 2 diabetes. The extent and pathways through which hepatic inflammation modulates insulin sensitivity in NAFLD are only partially understood. We explored the contribution of hepatic interleukin (IL)-1 signalling in a novel conditional knockout mouse model and expand the knowledge on this signalling pathway with regard to its liver-specific functions.

METHODS

A high-fat, high-carbohydrate diet (HFD) over 12 weeks was used in male hepatocyte-specific IL-1 receptor type 1 (IL-1R1) knockout mice (Il1r1Hep-/- ) and wild-type (WT) littermates.

RESULTS

Both genotypes developed an obese phenotype and accompanying macrovesicular hepatic steatosis. In contrast to WT mice, microvesicular steatosis and ballooning injury was less pronounced in HFD-fed Il1r1Hep-/- mice, and alanine aminotransferase remained in the normal range. This was paralleled by the suppression of injurious and proinflammatory hepatic c-Jun N-terminal kinases and extracellular signal-regulated kinases signalling, stable peroxisome proliferator activated receptor gamma coactivator-1alpha and farnesoid X receptor-alpha expression and preservation of mitochondrial function. Strikingly, despite HFD-feeding Il1r1Hep-/- mice remained highly insulin sensitive as indicated by lower insulin levels, homeostatic model assessment for insulin resistance, higher glucose tolerance, more stable hepatic insulin signalling cascade, and less adipose tissue inflammation compared to the WT.

CONCLUSIONS

The current data highlights that hepatocyte IL-1R1 contributes to hepatic and extrahepatic insulin resistance. Future liver-directed therapies in NAFLD could have effects on insulin sensitivity when improving hepatic inflammation and IL-1R1 signalling.

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.

The Insulin Receptor: An Important Target for the Development of Novel Medicines and Pesticides

The insulin receptor (IR) is a transmembrane protein that is activated by ligands in insulin signaling pathways. The IR has been considered as a novel therapeutic target for clinical intervention, considering the overexpression of its protein and A-isoform in multiple cancers, Alzheimer's disease, and Type 2 diabetes mellitus in humans. Meanwhile, it may also serve as a potential target in pest management due to its multiple physiological influences in insects. In this review, we provide an overview of the structural and molecular biology of the IR, functions of IRs in humans and insects, physiological and nonpeptide small molecule modulators of the IR, and the regulating mechanisms of the IR. Xenobiotic compounds and the corresponding insecticidal chemicals functioning on the IR are also discussed. This review is expected to provide useful information for a better understanding of human IR-related diseases, as well as to facilitate the development of novel small-molecule activators and inhibitors of the IR for use as medicines or pesticides.

Molecular Basis of Irisin Regulating the Effects of Exercise on Insulin Resistance

Insulin resistance is recognized as one major feature of metabolic syndrome, and frequently emerges as a difficult problem encountered during long-term pharmacological treatment of diabetes. Insulin resistance often causes organs or tissues, such as skeletal muscle, adipose, and liver, to become less responsive or resistant to insulin. Exercise can promote the physiological function of those organs and tissues and benefits insulin action via increasing insulin receptor sensitivity, glucose uptake, and mitochondrial function. This is done by decreasing adipose tissue deposition, inflammatory cytokines, and oxidative stress. However, understanding the mechanism that regulates the interaction between exercise and insulin function becomes a challenging task. As a novel myokine, irisin is activated by exercise, released from the muscle, and affects multi-organ functions. Recent evidence indicates that it can promote glucose uptake, improve mitochondrial function, alleviate obesity, and decrease inflammation, as a result leading to the improvement of insulin action. We here will review the current evidence concerning the signaling pathways by which irisin regulates the effect of exercise on the up-regulation of insulin action in humans and animals.

Identification of the Potential Molecular Mechanisms Linking RUNX1 Activity with Nonalcoholic Fatty Liver Disease, by Means of Systems Biology

Nonalcoholic fatty liver disease (NAFLD) is the most prevalent chronic hepatic disease; nevertheless, no definitive diagnostic method exists yet, apart from invasive liver biopsy, and nor is there a specific approved treatment. Runt-related transcription factor 1 (RUNX1) plays a major role in angiogenesis and inflammation; however, its link with NAFLD is unclear as controversial results have been reported. Thus, the objective of this work was to determine the proteins involved in the molecular mechanisms between RUNX1 and NAFLD, by means of systems biology. First, a mathematical model that simulates NAFLD pathophysiology was generated by analyzing Anaxomics databases and reviewing available scientific literature. Artificial neural networks established NAFLD pathophysiological processes functionally related to RUNX1: hepatic insulin resistance, lipotoxicity, and hepatic injury-liver fibrosis. Our study indicated that RUNX1 might have a high relationship with hepatic injury-liver fibrosis, and a medium relationship with lipotoxicity and insulin resistance motives. Additionally, we found five RUNX1-regulated proteins with a direct involvement in NAFLD motives, which were NFκB1, NFκB2, TNF, ADIPOQ, and IL-6. In conclusion, we suggested a relationship between RUNX1 and NAFLD since RUNX1 seems to regulate NAFLD molecular pathways, posing it as a potential therapeutic target of NAFLD, although more studies in this field are needed.

Cytokine-inducible SH2 domain containing protein contributes to regulation of adiposity, food intake, and glucose metabolism

The cytokine-inducible SH2 domain containing protein (CISH) is the founding member of the suppressor of cytokine signaling (SOCS) family of negative feedback regulators and has been shown to be a physiological regulator of signaling in immune cells. This study sought to investigate novel functions for CISH outside of the immune system. Mice deficient in CISH were generated and analyzed using a range of metabolic and other parameters, including in response to a high fat diet and leptin administration. CISH knockout mice possessed decreased body fat and showed resistance to diet-induced obesity. This was associated with reduced food intake, but unaltered energy expenditure and microbiota composition. CISH ablation resulted in reduced basal expression of the orexigenic Agrp gene in the arcuate nucleus (ARC) region of the brain. Cish was basally expressed in the ARC, with evidence of co-expression with the leptin receptor (Lepr) gene in Agrp-positive neurons. CISH-deficient mice also showed enhanced leptin responsiveness, although Cish expression was not itself modulated by leptin. CISH-deficient mice additionally exhibited improved insulin sensitivity on a high-fat diet, but not glucose tolerance despite reduced body weight. These data identify CISH as an important regulator of homeostasis through impacts on appetite control, mediated at least in part by negative regulation of the anorexigenic effects of leptin, and impacts on glucose metabolism.

Using Intermittent Fasting as a Non-pharmacological Strategy to Alleviate Obesity-Induced Hypothalamic Molecular Pathway Disruption

Intermittent fasting (IF) is a popular intervention used to fight overweight/obesity. This condition is accompanied by hypothalamic inflammation, limiting the proper signaling of molecular pathways, with consequent dysregulation of food intake and energy homeostasis. This mini-review explored the therapeutic modulation potential of IF regarding the disruption of these molecular pathways. IF seems to modulate inflammatory pathways in the brain, which may also be correlated with the brain-microbiota axis, improving hypothalamic signaling of leptin and insulin, and inducing the autophagic pathway in hypothalamic neurons, contributing to weight loss in obesity. Evidence also suggests that when an IF protocol is performed without respecting the circadian cycle, it can lead to dysregulation in the expression of circadian cycle regulatory genes, with potential health damage. In conclusion, IF may have the potential to be an adjuvant treatment to improve the reestablishment of hypothalamic responses in obesity.

Elongin C (ELOC/TCEB1)-associated von Hippel-Lindau disease

Around 95% of patients with clinical features that meet the diagnostic criteria for von Hippel-Lindau disease (VHL) have a detectable inactivating germline variant in VHL. The VHL protein (pVHL) functions as part of the E3 ubiquitin ligase complex comprising pVHL, elongin C, elongin B, cullin 2 and ring box 1 (VCB-CR complex), which plays a key role in oxygen sensing and degradation of hypoxia-inducible factors. To date, only variants in VHL have been shown to cause VHL disease. We undertook trio analysis by whole-exome sequencing in a proband with VHL disease but without a detectable VHL mutation. Molecular studies were also performed on paired DNA extracted from the proband's kidney tumour and blood and bioinformatics analysis of sporadic renal cell carcinoma (RCC) dataset was undertaken. A de novo pathogenic variant in ELOC NM_005648.4(ELOC):c.236A>G (p.Tyr79Cys) gene was identified in the proband. ELOC encodes elongin C, a key component [C] of the VCB-CR complex. The p.Tyr79Cys substitution is a mutational hotspot in sporadic VHL-competent RCC and has previously been shown to mimic the effects of pVHL deficiency on hypoxic signalling. Analysis of an RCC from the proband showed similar findings to that in somatically ELOC-mutated RCC (expression of hypoxia-responsive proteins, no somatic VHL variants and chromosome 8 loss). These findings are consistent with pathogenic ELOC variants being a novel cause for VHL disease and suggest that genetic testing for ELOC variants should be performed in individuals with suspected VHL disease with no detectable VHL variant.

The Purinergic Landscape of Type 2 Diabetes Mellitus

Adenosine triphosphate (ATP) is the key energy intermediate of cellular metabolic processes and a ubiquitous extracellular messenger. As an extracellular messenger, ATP acts at plasma membrane P2 receptors (P2Rs). The levels of extracellular ATP (eATP) are set by both passive and active release mechanisms and degradation processes. Under physiological conditions, eATP concentration is in the low nanomolar range but can rise to tens or even hundreds of micromoles/L at inflammatory sites. A dysregulated eATP homeostasis is a pathogenic factor in several chronic inflammatory diseases, including type 2 diabetes mellitus (T2DM). T2DM is characterized by peripheral insulin resistance and impairment of insulin production from pancreatic β-cells in a landscape of systemic inflammation. Although various hypoglycemic drugs are currently available, an effective treatment for T2DM and its complications is not available. However, counteracting systemic inflammation is anticipated to be beneficial. The postulated eATP increase in T2DM is understood to be a driver of inflammation via P2X7 receptor (P2X7R) activation and the release of inflammatory cytokines. Furthermore, P2X7R stimulation is thought to trigger apoptosis of pancreatic β-cells, thus further aggravating hyperglycemia. Targeting eATP and the P2X7R might be an appealing novel approach to T2DM therapy.

MiR-183-5p Induced by Saturated Fatty Acids Hinders Insulin Signaling by Downregulating IRS-1 in Hepatocytes

Excessive saturated fatty acids (SFA) uptake is known to be a primary cause of obesity, a widely acknowledged risk factor of insulin resistance and type 2 diabetes. Although specific microRNAs (miRNAs) targeting insulin signaling intermediates are dysregulated by SFA, their effects on insulin signaling and sensitivity are largely unknown. Here, we investigated the role of SFA-induced miR-183-5p in the regulation of proximal insulin signaling molecules and the development of hepatic insulin resistance. HepG2 hepatocytes treated with palmitate and the livers of high-fat diet (HFD)-fed mice exhibited impaired insulin signaling resulting from dramatic reductions in the protein expressions of insulin receptor (INSR) and insulin receptor substrate-1 (IRS-1). Differential expression analysis showed the level of miR-183-5p, which tentatively targets the 3'UTR of IRS-1, was significantly elevated in palmitate-treated HepG2 hepatocytes and the livers of HFD-fed mice. Dual-luciferase analysis showed miR-183-5p bound directly to the 3'UTR of IRS-1 and reduced IRS-1 expression at the post-transcriptional stage. Moreover, transfection of HepG2 hepatocytes with miR-183-5p mimic significantly inhibited IRS-1 expression and hindered insulin signaling, consequently inhibiting insulin-stimulated glycogen synthesis. Collectively, this study reveals a novel mechanism whereby miR-183-5p induction by SFA impairs insulin signaling and suggests miR-183-5p plays a crucial role in the pathogenesis of hepatic insulin resistance in the background of obesity.