Insulin Regulation Research Articles

232-LB: Transcriptional Regulation of Adipocyte Insulin and Inflammatory Signaling by Early B-Cell Factor-1 (Ebf1)

Overnutrition is causally associated with many chronic diseases, including insulin resistance and diabetes, heart disease, hypertension, and cancer. Chronic activation of the innate immune system may lie at the heart of a majority of T2DM cases; the bulk of the evidence suggests that a litany of inflammatory cytokines and toxic lipid species released from irritated adipocytes contribute significantly to disrupted insulin signaling in metabolic tissues and may eventually lead to frank type 2 diabetes. However, the molecular mechanisms that initiate these inflammatory events in adipocytes remain unknown, particularly at the transcriptional level. Our previous work showed that the transcription factor Ebf1 regulates insulin signaling and promotes inflammation in adipocytes; however, the precise molecular mechanisms through which Ebf1 regulates the expression of inflammatory loci remain unknown (as evidence had suggested Ebf1 regulates these genes indirectly). We have recently discovered that Ebf1 can physically interact with multiple subunits of the well-known inflammatory transcription factor NF-κB, and many of the critical inflammatory loci showing impaired expression in Ebf1-deficient 3T3-L1 adipocytes also happen to be well-established NF-κB target genes. This striking result likely explains our paradoxical observations that EBF1 directly (and positively) regulates several core insulin signaling genes (Pik3r1, Akt, etc.) but also promotes insulin resistance in adipocytes—apparently without directly occupying inflammatory loci. We are currently working on physically and functionally characterizing these interactions and propose a model to explain the previously-mentioned paradox. If our hypothesis is correct, we anticipate that the eventual development of pharmaceutical agents designed to interfere with EBF1-NF-κB protein-protein interactions may represent a viable treatment for overnutrition-associated diabetes. Disclosure A. Gutierrez: None. Y. Martinez: None. K. Ibarra: None. Z. Bailey: None. M. Griffin: None. Funding National Institute of Diabetes and Digestive and Kidney Diseases

199-OR: Optogenetic Control of Pancreatic Delta Cells Reveals Their Central Role in Hormone Release from Pancreatic Islets

Diabetes mellitus is a metabolic disorder resulting from insufficient insulin release and associated with dysregulation of glucagon secretion. Somatostatin secreted from pancreatic δ-cells is a strong paracrine factor for both insulin and glucagon secretion in islets. Here, we developed an optogenetic approach, through specific expressing light-sensitive channels/pumps in δ-cells, to investigate the paracrine control of hormone release from islets. We generated mouse models that express either a light-sensitive cation channel, channelrhodopsin-2 (ChR2), or a chloride pump, halorhodopsin (HR), specifically in the pancreatic δ-cells (SST-ChR2 and SST-HR mouse). Their specific expression was confirmed by immunostaining. Optoactivation of ChR2 at 1mM glucose rapidly depolarized δ-cells by 37mV (n=5) and stimulated electrical activity and somatostatin release. At high glucose or tolbutamide, light activation of HR repolarized δ-cells by 15 mV (n=3), suppressing action potentials. Optoactivation of SST-ChR2 δ-cells suppressed, after a variable delay depending on the distance from δ-cells, action potential firing in neighbouring α-cells, inhibited exocytosis by 30% (n=5) and glucagon secretion by 55% at 1mM glucose (n=7). In a subset (35%) α-cells with no spontaneous action potentials, opto-inhibition of SST-HR δ-cells caused a 9mV depolarization (n=7) and induced action potential firing, which may account for the stimulation of glucagon secretion. Neither optoactivation, nor opto-inhibition of δ-cells affected insulin secretion at hypo- and hyperglycaemia. However, at normoglycaemia (6 mM glucose), optoactivation of δ-cells depolarized neighbouring β-cells (via gap-junctions) and evoked action potential firing, leading to a paradoxical 160% stimulation of insulin secretion (n=9). We conclude that δ-cells play a central role in the regulation of both insulin and glucagon release but that the effects are more complex than appreciated to date. Disclosure H.Dou: None. C.A.Miranda: None. J.Tolö: None. Q.Zhang: None. P.Rorsman: None. Funding Swedish Research Council

290-OR: FoxK1-Associated Gene Regulatory Network—A New Transcriptional Regulator of Hepatic Insulin Action

Insulin acts on the liver to maintain glucose homeostasis, and disruption of insulin action in liver is central in the pathogenesis of diabetes and metabolic syndrome. While most previous studies of insulin action on gene expression in liver have focused on FoxO1, we have found that Forkhead box protein K1 (FoxK1) is another important regulator of hepatic gene expression which acts in a complementary manner. Thus, upon insulin stimulation, FoxK1 translocates from the cytoplasm to nucleus while FoxO1 translocates from nucleus to cytoplasm. Chromatin immunoprecipitation (ChIP) sequencing shows that FoxK1 binds to >1000 gene regulatory elements in the proximal promoters and enhancers in hepatic chromatin, with TGTTTAC being the major FoxK1 DNA binding motif. De novo motif analysis suggested that HNF4A is also one of the major co-regulators for FoxK1 in mediating gene expression. Insulin stimulated binding of FoxK1 to promoters was observed in up-regulation of genes involved in steroid biosynthesis and cell cycle, and down-regulation of genes involved in autophagy. FoxK1 is also a potential transcription factor for insulin receptor (IRβ) mediated gene regulation as evidenced by its binding to LARS1 and TIMM22 promoters. Both FoxK1 and IRβ share regulation of genes involved in rRNA processing, mitotic cell cycle and nonsense-mediated decay. Interestingly, gene promoters of genes in glucose metabolism (PCK1, G6PC and PKM) are bound by FoxK1, but not by IRβ in response to insulin. FoxK1 can also work with FoxO1 in regulation of genes involved in mitochondrial translation, and with both IRβ and FoxO1 in insulin regulation of AHCY, PPRC1, and CDKN1A, i.e., genes involved in cell senescence, amino acid metabolism and mitochondrial biogenesis. Thus, FoxK1 is a potential factor priming the response to insulin and helps with the recruitment of IRβ or FoxO1 in regulation of gene expression in liver in metabolism and other important biological pathways. Disclosure P.Allu: None. H.Pan: None. J.Dreyfuss: None. C.Kahn: None.

The Influence of Leptin Resistance on the Development of Childhood Obesity

The rising global prevalence of obesity presents a diminished quality of life and life expectancy. Though a myriad of factors contributes to obesity, one of the leading factors is excessive adipose tissue accumulation increases the body’s production of the leptin satiety hormone resulting in leptin resistance. Leptin resistance results in increased vulnerability to obesity through improper regulation of insulin, a decline in metabolic functions, and decreased sex hormone levels. Leptin resistance is treated with natural treatments, leptin replacement therapy, testosterone replacement therapy, and insulin-sensitizing drugs, although all are met with limited results. Since leptin vastly affects sex hormone levels, leptin resistance has an adverse effect on obese children and adolescents. In this review, we examine the causes of leptin resistance, treatments for leptin resistance, and the effect of leptin resistance on childhood development.

A Network Pharmacology Study on the Similarities and Differences in the Mechanisms of Zuo Gui Wan/You Gui Wan for the Treatment of Premature Ovarian Failure.

Premature ovarian failure is a heterogeneous disease that severely affects the quality of life of women in their reproductive years. The ancient classical Chinese medicine compounds Zuo Gui Wan and You Gui Wan have great potential to treat premature ovarian failure, but the similarities and differences in their pharmacological mechanisms for treating POF are not yet clear. In this study, the public database was used to screen the active ingredients and potential targets of Zuo Gui Wan and You Gui Wan. The similarities and differences in the potential targets of both pills for the treatment of POF were analysed using the POF-related genes obtained from OMIM and GeneCards. The protein-protein interaction network was established and collated to form a drug-active ingredient-target gene network using STRING. Finally, the drug-target-pathway network was constructed by enrichment analysis to find the differences in target enrichment on the same pathway. Pharmacological analysis of the network showed that Zuo Gui Wan contains 72 active ingredients, while You Gui Wan has 112. A total of 62 common compositions, such as quercetin and kaempferol, were identified. Amongst them were 10 unique compounds, such as hydroxyproline and cholesterol, in Zuo Gui Wan and 50 exclusive compounds, such as Karanjin and betacarotene, in You Gui Wan. In addition, 14 overlapping targets, including MAPK1, CXCL8, TNF, IL6, and EGFR, were determined amongst the first 20 targets in the treatment of POF by both pills, demonstrating that the core mechanism of POF treatment is similar between the two. Pathway enrichment analysis showed 87 identical and significant pathways between Zuo Gui Wan and You Gui Wan, including IL-17, TNF, PI3K-Akt, oestrogen, VEGF, and other pathways. Zuo Gui Wan has 12 special pathways, such as natural killer cell-mediated cytotoxicity and intestinal immune network for IgA production. You Gui Wan has nine unique pathways, such as insulin secretion and glucagon signalling pathway. Zuo Gui Wan and You Gui Wan could treat POF by inhibiting oxidative stress and inflammation, regulating hormone levels, improving ovarian function, and promoting follicular development. Zuo Gui Wan is inclined to immune regulation, while You Gui Wan prefers insulin regulation. Therefore, similarities and differences clearly exist in the specific mechanisms of Zuo Gui Wan and You Gui Wan in the treatment of POF.

Bombesin receptors in GtoPdb v.2023.1

Mammalian bombesin (Bn) receptors comprise 3 subtypes: BB1, BB2, BB3 (nomenclature recommended by the NC-IUPHAR Subcommittee on bombesin receptors, [117, 4]). BB1 and BB2 are activated by the endogenous ligands neuromedin B (NMB), gastrin-releasing peptide (GRP), and GRP-(18-27). bombesin is a tetra-decapeptide, originally derived from amphibians and structurally closely related to GRP. The three Bn receptor subtypes couple primarily to the Gq/11 and G12/13 family of G proteins [117]. Each of these receptors is widely distributed in the CNS and peripheral tissues [80, 117, 261, 290, 248, 375, 114, 164, 165]. Activation of BB1 and BB2 receptors causes a wide range of physiological/pathophysiogical actions, including the stimulation of normal and neoplastic tissue growth, smooth-muscle contraction, respiration, gastrointestinal motility, feeding behavior, secretion and many central nervous system effects including regulation of circadian rhythm, body temperature control, sighing, behavioral disorders and mediation of pruritus [153, 211, 255, 117, 205, 261, 318, 70, 35, 345, 212, 36]. BB3 is an orphan receptor, although some propose it is constitutively active [330]. BB3 receptor knockout studies show it has important roles in glucose and insulin regulation, metabolic homeostasis, feeding, regulation of body temperature, obesity, diabetes mellitus and growth of normal/neoplastic tissues [152, 80, 168, 224, 359, 209]. Bn receptors are one of the most frequently overexpressed receptors in cancers and are receiving increased attention for their roles in tumor growth, as well as for tumour imaging and for receptor-targeted cytotoxicity [211, 288, 9, 167, 171, 172, 135, 202]. Bn receptors are also receiving attention because they are one of the primary neurotransmitters for pruritus [36, 127, 35, 318].

Carbohydrate Intake and Oral Glucose Tolerance Test Results in the Postpartum Period.

The American Diabetes Association (ADA) recommends a 3-day preparatory diet prior to a diagnostic oral glucose tolerance test (OGTT), a test often recommended in postpartum individuals with a history of gestational diabetes (GDM). Evaluate the relationship between carbohydrate intake and OGTT glucose in 2 cohorts of postpartum individuals. We performed analyses of postpartum individuals from 2 prospective studies with recent GDM (Balance after Baby Intervention, BABI, n = 177) or risk factors for GDM (Study of Pregnancy Regulation of INsulin and Glucose, SPRING, n = 104) .We measured carbohydrate intake using 24-hour dietary recalls (SPRING) or Food Frequency Questionnaire (BABI) and performed 2-hour 75-g OGTTs. The main outcome measure was 120-minute post-OGTT glucose. There was no relationship between carbohydrate intake and 120-minute post-OGTT glucose level in either study population (SPRING: β = 0.03, [-5.5, 5.5] mg/dL, P = .99; BABI: β = -3.1, [-9.5, 3.4] mg/dL, P = .35). Adding breastfeeding status to the model did not change results (SPRING β = -0.14, [-5.7, 5.5] mg/dL, P = .95; BABI β = -3.9, [-10.4, 2.7] mg/dL, P = .25). There was, however, an inverse relationship between glycemic index and 120-minute post OGTT glucose (BABI: β = -1.1, [-2.2, -0.03] mg/dL, P = .04). Carbohydrate intake is not associated with post-OGTT glucose levels among postpartum individuals. Dietary preparation prior to the OGTT may not be necessary in this population.

Morus Plant Genus: Superb Antidiabetic Activity and Outstanding Source of Nutrients

The plant genus Morus (Mulberry) has been used by humans for many centuries. All parts of the trees are used, but the fruits have the highest nutritional values. Most of the species of this genus were studied for various medicinal and biological activities, as well as many other properties, including chemical composition. Two species, Morus alba and Morus nigra were very extensively investigated, and research reports about them continue to be published very frequently. The chemistry of this plant genus is fascinating. It includes numerous natural products with unique structures and structure-sub-units, making them excellent candidates as organic synthesis starting materials. Many review articles were published about the Morus genus and some of its species, but this article is the most comprehensive regarding antidiabetic activity and insulin regulation. Active natural products are responsible for these activities will be presented, as well as possible and proposed mechanisms of action. Ethnobotanical and ethnomedicinal information related to the antidiabetic activity will be briefly presented. In addition, a thorough discussion section will lead to conclusions, some future directions, and recommendations for research.

Inhibition mechanism of human insulin fibrillation by Bodipy carbon polymer dots and photothermal defibrillation effect of Bodipy carbon polymer dots modified by ThT

Fibrillation process of human insulin (HI) is closely related to type 2 diabetes (T2D). In the present work, Carbon Polymer Dots (CPDs) was synthesized by Bodipy to control the process of insulin fibrillation. The inhibition process of insulin fibrillation with the existence of CPDs was completed investigated. The hydrophobic interaction of CPDs and insulin was used to inhibit the change of insulin's secondary structure in the lag phase and growth period. ThT fluorescence analysis and transmission electron microscopy (TEM) characterization of the CPDs were used to explore the kinetics of insulin fibrillation and regulation process by CPDs. Isothermal titration calorimetry (ITC) was applied to explore the regulatory mechanism by CPDs at all stages of the insulin fibrillation process. ThT was used to complete the chemical modification of CPDs by Friedel-Crafts alkylation, which made the CPDs maintain the characteristics of photothermal effect and also obtain the ability to bind specifically to the fibers. Finally, the process of defibrillation of human insulin fibers under the Near-infrared light's irradiation was realized. In this work, we clarified the mechanism of the regulation process by Bodipy CPDs and made CPDs able to defibrillate the insulin fibers by chemical modification.

Response to acute hyperglycemia and high fructose in cultured tenocytes.

High monosaccharide levels are intimately associated with diabetes and impact tendon cells through inflammation and impairment in metabolic homeostasis. Experiments were designed to understand the responses elicited by cultured tenocytes under monosaccharide stress induced by hyperglycemia and hyperfructosemia. We simulated hyperglycemia and hyperfructosemia in vitro by treating tenocytes with media containing sublethal concentrations of glucose and fructose, respectively. Exposure of tenocytes to high glucose and high fructose altered the levels of IL-1β, IL-2, IL-6, IL10 and IL-17A. AMPK expression was increased in high-glucose and decreased in high-fructose groups. High fructose increased the level of IRS-1 compared with the control. Increased mitochondrial superoxide levels and compromised mitochondrial membrane integrity were exhibited by both the groups. The findings from the network analysis revealed many altered genes that are related to pathways for enzyme-linked receptor protein signaling, positive regulation of metabolic processes, transmembrane receptor tyrosine kinase pathway, insulin receptor signaling and regulation of cytokine production. Overall, the data suggest that the tenocytes under high monosaccharide levels exhibit survival responses by altering the expression status of cytokines and metabolic mediators that are involved in the underlying pathogenesis of tendinopathy.

Vinyl chloride enhances high-fat diet-induced proteome alterations in the mouse pancreas related to metabolic dysfunction.

Alterations in physiological processes in pancreas have been associated with various metabolic dysfunctions and can result from environmental exposures, such as chemicals and diet. It was reported that environmental vinyl chloride (VC) exposure, a common industrial organochlorine and environmental pollutant, significantly exacerbated metabolic-related phenotypes in mice fed concurrently with high-fat diet (HFD) but not low-fat diet (LFD). However, little is known about the role of the pancreas in this interplay, especially at a proteomic level. The present study was undertaken to examine the protein responses to VC exposure in pancreas tissues of C57BL/6J mice fed LFD or HFD, with focus on the investigation of protein expression and/or phosphorylation levels of key protein biomarkers of carbohydrate, lipid, and energy metabolism, oxidative stress and detoxification, insulin secretion and regulation, cell growth, development, and communication, immunological responses and inflammation, and biomarkers of pancreatic diseases and cancers. We found that the protein alterations may indicate diet-mediated susceptibility in mouse pancreas induced by HFD to concurrent exposure of low levels of inhaled VC. These proteome biomarkers may lead to a better understanding of pancreas-mediated adaptive or adverse response and susceptibility to metabolic disease.

Liraglutide on type 2 diabetes mellitus with nonalcoholic fatty liver disease: A systematic review and meta-analysis of 16 RCTs.

Nonalcoholic fatty liver disease (NAFLD) is a common comorbidity of type 2 diabetes mellitus (T2DM). Our aim is to investigate the effects of liraglutide on T2DM with NAFLD. Relevant articles published from the earliest publication to March 2022 were selected from several databases. The Cochrane Collaboration's RevMan software was used for the analysis. Sixteen studies are selected for this meta-analysis, which includes totally 634 patients in the treatment group and 630 patients in the control group. As a result, 14 studies show that fasting plasma glucose levels of the experimental group are lower than that of the control group; 15 studies show that glycosylated hemoglobin A1c levels of the experimental group are lower than that of the control group; 13 studies show that triglyceride levels of the experimental group are lower than that of the control group; twelve studies show that total cholesterol levels of the experimental group are lower than that of the control group; 10 studies show that alanine aminotransferase levels of the experimental group is lower than that of the control group; 10 studies show that no significant difference in changes in aspartate transaminase between 2 groups; 13 studies show that low density lipoprotein cholesterol levels of the experimental group is lower than that of the control group; 9 studies show that no significant difference in changes in high density lipoprotein cholesterol between 2 groups; 7 studies mentioned adverse effects and the difference is significant. Liraglutide is potentially curative for T2DM with NAFLD.

Insulin mimetic potential of Hylocereus undatus from extracted myo-inositol and proteins

Diseases are spreading like a trend and victimising every other individual globally. Here, we are referring to one such most common disease that has not even spared young lives i.e., diabetes. Annually, several people lose their lives and loved ones because of this dangerous disease. This has compelled the researchers to think and work on some life saving treatment. People suffering from hyperglycaemic conditions have insulin resistance which can be improved by intake of myo-inositol. Myo-inositol has potential to regulate this insulin hormone which can prevent and control diabetes mellitus. In this research, we have used a natural source (fruit) Hylocereus undatus; it has proved to be a good source of myo-inositol and some proteins that help in insulin regulation naturally. Several techniques and tests were performed such as extraction, purification, crystallisation, proteolytic activity assay, protein estimation, etc. Positive results of myo-inositol were observed through crystallisation together with decent amount of protein concentrations by Folin Lowry test and SDS-PAGE analysis.

A genetic strategy to measure insulin signaling regulation and physiology in Drosophila.

Insulin regulation is a hallmark of health, and impaired insulin signaling promotes metabolic diseases like diabetes mellitus. However, current assays for measuring insulin signaling in all animals remain semi-quantitative and lack the sensitivity, tissue-specificity or temporal resolution needed to quantify in vivo physiological signaling dynamics. Insulin signal transduction is remarkably conserved across metazoans, including insulin-dependent phosphorylation and regulation of Akt/Protein kinase B. Here, we generated transgenic fruit flies permitting tissue-specific expression of an immunoepitope-labelled Akt (AktHF). We developed enzyme-linked immunosorption assays (ELISA) to quantify picomolar levels of phosphorylated (pAktHF) and total AktHF in single flies, revealing dynamic tissue-specific physiological regulation of pAktHF in response to fasting and re-feeding, exogenous insulin, or targeted genetic suppression of established insulin signaling regulators. Genetic screening revealed Pp1-87B as an unrecognized regulator of Akt and insulin signaling. Tools and concepts here provide opportunities to discover tissue-specific regulators of in vivo insulin signaling responses.

The effect of PFASs on PPAR-gamma/RXR-alpha heterodimer.

Nuclear hormone receptors (NRs) are the main protein superfamily that regulates gene expressions in eukaryotic cells. Given the importance of their roles in cells, they become one of the main targets in drug discovery, including thiazolidinediones that act through an NR named peroxisome proliferator-activated receptor gamma (PPAR-gamma). 1 PPAR-gamma can perform as homodimer as well as heterodimer with retinoid X receptor alpha (RXR-alpha) in cells, and the heterodimer is known to impact the regulation of the synthesis of proteins responsible for insulin sensitivity. Per- and polyfluoroalkyl substances (PFASs) are forever chemicals that are being used in numerous industrial applications, including water-repellent coatings, fire-fighting foams, furniture, oil-repellents, and many more. PFAS compounds are very difficult to degrade due to their chemical properties. In recent years, the impact of PFASs on human health as well as on the environment has started to be investigated. Numerous studies show that these compounds disturb many biological systems in humans, including insulin and cholesterol regulation mechanisms, thyroid hormone levels, and so on. It has been shown that PPAR-gamma/RXR-alpha heterodimer is one of the potential targets for PFAS compounds, leading to problems in insulin metabolism. Here, we investigated the effects of selected PFAS compounds on PPAR-gamma/RXR-alpha heterodimer using molecular dynamics simulations and binding free energy calculations. We see that the chain length of PFAS compounds as well as the selection of functional groups impact the binding strength of PFAS compounds. Furthermore, L-carnitine compound, which is shown to have mitigating effects against PFASs, was also investigated.

Impact of tyrosine kinase inhibitors on glucose control and insulin regulation in patients with chronic myeloid leukemia.

Treatment with tyrosine kinase inhibitors (TKIs), especially nilotinib, often results in hyperglycemia, which may further increase cardiovascular disease risk in patients with chronic myeloid leukemia (CML). The mechanism underlying the TKI-induced glucose dysregulation is not clear. TKIs are suggested to affect insulin secretion but also insulin sensitivity of peripheral tissue has been proposed to play a role in the pathogenesis of TKI-induced hyperglycemia. Here, we aimed to assess whether skeletal muscle glucose uptake and insulin responses are altered in nondiabetic patients with CML receiving TKI treatment. After a glycogen-depleted exercise bout, an intravenous glucose bolus (0.3 g/kg body weight) was administered to monitor 2-h glucose tolerance and insulin response in 14 patients with CML receiving nilotinib, 14 patients with CML receiving imatinib, and 14 non-CML age- and gender-matched controls. A dynamic [18F]-FDG PET scan during a hyperinsulinemic-euglycemic clamp was performed in a subgroup of 12 male patients with CML to assess m. quadriceps glucose uptake. We showed that patients with CML treated with nilotinib have an increased insulin response to intravenous glucose administration after muscle glycogen-depleted exercise. Despite the increased insulin response to glucose administration in patients with CML receiving nilotinib, glucose disappearance rates were significantly slower in nilotinib-treated patients when compared with controls in the first 15 min after glucose administration. Although [18F]-FDG uptake in m. quadriceps was not different, patients receiving nilotinib showed a trend toward decreased glucose infusion rates during euglycemic clamping when compared with patients receiving imatinib. Together, these findings indicate disturbed skeletal muscle glucose handling in patients with CML receiving nilotinib therapy.NEW & NOTEWORTHY In this study, we have shown that non-diabetic patients with CML receiving nilotinib therapy show early signs of disturbed skeletal muscle glucose handling, which was not observed in imatinib-treated patients. These observations in nilotinib users may reflect decreased muscle insulin sensitivity, which could serve as a potential target to counteract glycemic dysregulation, and is of clinical importance since these patients have an increased cardiovascular disease risk.

Effects of Chromium, Inositol and Resistant Starch Supplementation In Pcos

Polycystic ovary syndrome (PCOS) is a diverse condition that has distinct signs and symptoms such as hyperandrogenism and chronic anovulation. It is a major hormonal disorder that affects the health-related quality of life and mental health of young women. The etiology of PCOS still remains uncertain but insulin resistance is one of the major factors seen in PCOS individuals which are characterized by the presence of acanthosis nigricans. Dietary interventions and lifestyle modification are being considered to be a first-line treatment for women with PCOS. Proper diet, adequate nutritional status, and following a physical activity routine help in alleviating the symptoms of PCOS. Dietary interventions should focus on weight management and insulin regulation. An abnormal gut microbiome function results in ovarian dysfunction, immune changes, insulin resistance, and disruption in bile synthesis. Therefore, gut health of women suffering from PCOS should be prioritized and interventions that improve the gut health should be followed. This systematic review is performed to investigate the association between micronutrient supplementation and PCOS. The related articles were searched using the databases PubMed, Science Direct, and Google Scholar. All the studies involving micronutrient supplementation and PCOS were included in this systematic review. Micronutrient supplementation was significantly inversely associated with improving PCOS prognosis. The main finding of the systematic review is that it concludes there is a direct association between micronutrient supplementation as it helps in alleviating the symptoms and maintaining a proper lifestyle in women with PCOS.

Serpentine Enhances Insulin Regulation of Blood Glucose through Insulin Receptor Signaling Pathway

Insulin sensitizers targeting insulin receptors (IR) are a potential drug for the treatment of diabetes. Serpentine is an alkaloid component in the root of Catharanthus roseus (L.) G. Don. Serpentine screened by surface plasmon resonance (SPR) technology has the ability to target IR. The objective of this study was to investigate whether serpentine could modulate the role of insulin in regulating blood glucose through insulin receptors in cells and in animal models of diabetes. SPR technology was used to detect the affinity of different concentrations of serpentine with insulin receptors. The Western blotting method was used to detect the expression levels of key proteins of the insulin signaling pathway in C2C12 cells and 3T3-L1 cells as well as in muscle and subcutaneous adipose tissue of diabetic mice after serpentine and insulin treatment. Diabetic mice were divided into four groups and simultaneously injected with insulin or serpentine, and the blood glucose concentration and serum levels of insulin, glucagon, and C-peptide were measured 150 min later. mRNA levels of genes related to lipid metabolism and glucose metabolism in liver, muscle, and subcutaneous adipose tissue were detected by RT-PCR. Serpentine was able to bind to the extracellular domain of IR with an affinity of 2.883 × 10-6 M. Serpentine combined with insulin significantly enhanced the ability of insulin to activate the insulin signaling pathway and significantly enhanced the glucose uptake capacity of C2C12 cells. Serpentine enhanced the ability of low-dose insulin (1 nM) and normal-dose insulin (100 nM) to activate the insulin signaling pathway. Serpentine also independently activated AMPK phosphorylation, thus stimulating glucose uptake by C2C12 cells. In high-fat-diet/streptozotocin (HFD/STZ)-induced diabetic mice, serpentine significantly prolonged the hypoglycemic time of insulin, significantly reduced the use of exogenous insulin, and inhibited endogenous insulin secretion. In addition, serpentine alone significantly increased the expression of GSK-3β mRNA in muscle tissue, thus enhancing glucose uptake, and at the same time, serpentine significantly increased glucagon secretion and liver gluconeogenesis. Serpentine enhances the ability of insulin to regulate blood glucose through the insulin receptor, and can also regulate blood glucose alone, but it has a negative regulation mechanism and cannot produce a hypoglycemic effect. Therefore, serpentine may be useful as an insulin sensitizer to assist insulin to lower blood glucose.

Young adult male LEW.1WR1 rats have reduced beta cell area and develop glucose intolerance

Prediabetes affects 1 in 3 American adults and is characterized by insulin resistance, insulin hypersecretion, and impaired glucose tolerance. Weanling LEW.1WR1 (1WR1) rats have increased blood insulin concentrations, so we hypothesized that young adult 1WR1 rats would develop impaired glucose tolerance due to the poor regulation of insulin. We monitored glucose tolerance, insulin tolerance, and weight gain for 10 weeks to assess if there was a decline in glucose processing over time. 1WR1 rats were significantly more glucose intolerant after 8 weeks. 1WR1 rats had increased body mass, yet abdominal fat mass was not significantly increased. Although the 1WR1 rats had increased circulating insulin and glucagon protein levels, 1WR1 rat beta cell area was significantly reduced. There may be underlying insulin resistance as evidenced by dysfunctional insulin regulation during fasting. Understanding the metabolic phenotype of this rat model can provide insight into the human pathophysiological changes that increase susceptibility to glucose intolerance and prediabetes.

Sirt3 deficiency induced down regulation of insulin degrading enzyme in comorbid Alzheimer’s disease with metabolic syndrome

SIRT3 deacetylates mitochondrial proteins, thereby enhancing their function. We have previously demonstrated that Sirt3 gene deletion leads to brain mitochondrial dysfunction and neuroinflammation. We also reported that silencing of Sirt3 gene in APP/PS1 mice results in exacerbation of insulin resistance, neuroinflammation and β amyloid plaque deposition. To further understand how metabolic syndrome and amyloid pathology interact, we performed RNA-seq analysis of the brain samples of APP/PS1/Sirt3-/- mice. Gene expression patterns were modulated in metabolic and inflammatory pathways by Sirt3 gene deletion, amyloid pathology, and the combination. Following Sirt3 gene deletion, a key finding was the decreased expression of insulin-degrading enzyme (IDE), an enzyme that regulates the levels of insulin and Aβ peptides. Western diet feeding of Sirt3-/- and APP/PS1 mice resulted in decrease of IDE protein, parallel to Sirt3 downregulation. Conversely, activation of SIRT3 by nicotinamide riboside in vivo and in vitro resulted in IDE upregulation. SIRT3 activation in vivo also increased the levels of neprilysin, another Aβ degrading enzyme and decreased the levels of BACE1 which generates Aβ peptide suggesting SIRT3’s role in amyloid plaque reduction. Our findings provide a plausible mechanism linking metabolic syndrome and amyloid pathology. SIRT3 may be a potential therapeutic target to treat AD.