Decreased Insulin Resistance by Myo-Inositol Is Associated with Suppressed Interleukin 6/Phospho-STAT3 Signaling in a Rat Polycystic Ovary Syndrome Model

Dietary modulation of microRNAs in insulin resistance and type 2 diabetes

The prevalence of type 2 diabetes is increasing worldwide. Various molecular mechanisms have been proposed to interfere with the insulin signaling pathway. Recent advances in proteomics and genomics indicate that one such mechanism involves the post-transcriptional regulation of insulin signaling by microRNA (miRNA). These noncoding RNAs typically induce messenger RNA (mRNA) degradation or translational repression by interacting with the 3' untranslated region (3'UTR) of target mRNA. Dietary components and patterns, which can either enhance or impair the insulin signaling pathway, have been found to regulate miRNA expression in both in vitro and in vivo studies. This review provides an overview of the current knowledge of how dietary components influence the expression of miRNAs related to the control of the insulin signaling pathway and discusses the potential application of these findings in precision nutrition.

Diacerein and myo-inositol alleviate letrozole-induced PCOS via modulation of HMGB1, SIRT1, and NF-kB: A comparative study

Polycystic ovary syndrome (PCOS) is the most prevalent cause of anovulatory infertility in women. Myo-inositol supplementation has displayed effectiveness in curing PCOS patients. Diacerein, an anti-inflammatory medication, has not been extensively studied in the context of reproductive disorders. This study aimed to compare the role of myo-inositol and diacerein in PCOS and the probable mechanisms mediating their actions. Forty adult female rats were divided equally into the following: control, PCOS, PCOS+Myo-inositol, and PCOS+Diacerein groups. Rats were subjected to arterial blood pressure (ABP), electromyography (EMG), and uterine reactivity measurements. Blood samples were collected for measuring hormonal assays, glycemic state, lipid profile, oxidative stress, and inflammatory markers. Ovaries and uteri were extracted for histological examination, including hematoxylin and eosin staining, Masson's trichrome staining, immunohistochemistry, and rt-PCR analysis of ovarian tissues. PCOS was associated with significant increases in ABP, uterine frequency and amplitude of contraction, luteinizing hormone, testosterone, lipid, glycemic and inflammatory markers, malondialdehyde, high-mobility group box 1 (HMGB1), nuclear factor kappa (NF-kB), ovarian fibrosis, and endometrial thickening. In contrast, there was a significant reduction in follicular stimulating hormone, reduced glutathione, and Sirtuin 1 (SIRT1) when compared with control group. Both myo-inositol and diacerein counteract PCOS changes; but diacerein's effects were superior to myo-inositol's for all parameters, except for lipid and glycemic markers. Diacerein possessed anti-inflammatory properties and showed significant efficacy in mitigating the endocrinal, metabolic, and ovarian structural alterations linked to PCOS. Its beneficial actions likely stem from reducing oxidative stress, dyslipidemia, and hyperglycemia, potentially through the modulation of HMGB1, SIRT1, and NF-kB pathways.

Myo-inositol rescued insulin resistance and dyslipidemia in db/db mice

Myo-inositol (MI), present in a variety of foods, is essential in several important processes of cell physiology. In this study, we explored the protective effects of MI against hyperglycemia and dyslipidemia in db/db mice, a typical animal model of type 2 diabetes mellitus (T2DM). MI supplement effectively suppressed the high plasma glucose and insulin levels and markedly relieved the insulin resistance (IR) in the db/db mice, comparable to metformin's effects. In MIN6 pancreatic β cells, MI also restrained the upsurge of insulin secretion stimulated by high-concentration glucose but had no impact on the promoted cell proliferation. Moreover, MI abated the enhanced plasma triglyceride and total cholesterol levels in the db/db mice. Notably, the lipid droplet formation of mesenchymal stem cells (MSCs) from db/db mice was significantly diminished after the treatment of MI, indicating that MI could effectively inhibit the differentiation of db/db mouse MSCs into adipocytes. However, MI regretfully failed to control obesity in db/db mice. This work proved that MI significantly helped db/db mice's metabolic disorders, indicating that MI has potential as an effective adjunctive treatment for hyperglycemia and dyslipidemia in T2DM patients.

Impact of erythropoietin and myoinositol versus metformin on insulin resistance in a rat model of polycystic ovary syndrome

This study aimed to evaluate the therapeutic role of erythropoietin (EPO) or myoinositol versus metformin (MET) in improving the reproductive functions and glucose tolerance in a rat model of polycystic ovary (PCOS). Oral letrozole (LTZ) was used for induction of PCOS in wester rats for 21 days, after that, MET, EPO and myoinositol were administered for the following 21 days. The LTZ-induced PCOS rats have lost their oestrous cyclicity and become fixed at the diestrus phase, developed insulin resistance, abnormal sex and gonadotrophin hormone serum levels, increased cystic follicles, decreased number of the growing follicles and very little or no corpora lutea on microscopic examination, which were reversed by the three drugs, MET, EPO and myoinositol. MET and myoinositol were mostly equally effective in improving the reproductive manifestations of the disease. However, EPO was most effective in decreasing the insulin level observed in this LTZ-induced model of PCOS.

D-Chiro-Inositol and Myo-Inositol Induce WAT/BAT Trans-Differentiation in Two Different Human Adipocyte Models (SGBS and LiSa-2)

White adipose tissue/brown adipose tissue trans-differentiation is one of the main study targets for therapies against obesity and metabolic diseases. In recent years, numerous molecules able to induce such trans-differentiation have been identified; however, their effect in obesity therapies has not been as expected. In the present study, we investigated whether myo-inositol and its stereoisomer D-chiro-inositol could be involved in the browning of white adipose tissue. Our preliminary results clearly indicate that both, at 60 μM concentration, induce the upregulation of uncoupling protein 1 mRNA expression, the main brown adipose tissue marker, and increase mitochondrial copy number as well as oxygen consumption ratio. These changes demonstrate an activation of cell metabolism. Therefore, our results show that human differentiated adipocytes (SGBS and LiSa-2), assume the features typical of brown adipose tissue after both treatments. Furthermore, in the cell lines examined, we proved that D-chiro-inositol and myo-Inositol induce an increase in the expression of estrogen receptor mRNAs, suggesting a possible modulation by these isomers. We also found an increase in the mRNA of peroxisome proliferator-activated receptor gamma, a very important target in lipid metabolism and metabolic diseases. Our results open new opportunities for the use of inositols in therapeutic strategies to counteract obesity and its metabolic complications.

The Role of Peroxisome Proliferator-Activated Receptors in Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) constitutes the most common endocrine disorder in women of reproductive age. Patients usually suffer from severe menstrual irregularities, skin conditions, and insulin resistance-associated health conditions. Peroxisome proliferator-activated receptors (PPARs) are nuclear receptor proteins that regulate gene expression. In order to investigate the role of PPARs in the pathophysiology of PCOS, we conducted a literature review using the MEDLINE and LIVIVO databases and were able to identify 74 relevant studies published between 2003 and 2023. Different study groups reached contradictory conclusions in terms of PPAR expression in PCOS. Interestingly, numerous natural agents were found to represent a novel, potent anti-PCOS treatment alternatives. In conclusion, PPARs seem to play a significant role in PCOS.

Autophagy: An Emerging Target for Developing Effective Analgesics

Inadequate treatment of acute and chronic pain causes depression, anxiety, sleep disturbances, and increased mortality. Abuse and overdose of opioids and the side effects associated with chronic use of NSAID illustrate the need for development of safer and effective pain medication. Working toward this end, an in silico tool based on an emergent intelligence analytical platform that examines interactions between protein networks was used to identify molecular mechanisms involved in regulating the body's response to painful stimuli and drug treatments. Examining interactions between protein networks associated with the expression of over 20 different pain types suggests that the regulation of autophagy plays a central role in modulation of pain symptoms (see Materials and Methods). Using the topology of this regulatory scheme as an in silico screening tool, we identified that combinations of functions targeted by cannabidiol, myo-inositol, and fish oils with varying ratios of eicosapentaenoic and docosahexaenoic acids are projected to produce superior analgesia. For validating this prediction, we administered combinations of cannabidiol, myo-inositol, and fish oils to rats that received formalin injections in hind paws, prior to substance administration, and showed that analgesic effects produced by these combinations were comparable or superior to known NSAID analgesics, which suggests that these combinations have potential in treatment of pain.

Effects of Anterior Pituitary Adenomas' Hormones on Glucose Metabolism and Its Clinical Implications

Pituitary adenomas have recently become more common and their incidence is increasing yearly. Functional pituitary tumors commonly secrete prolactin, growth hormones, and adrenocorticotropic hormones, which cause diseases such as prolactinoma, acromegaly, and Cushing's disease, but rarely secrete luteinizing, follicle-stimulating, thyroid-stimulating, and melanocyte-stimulating hormones. In addition to the typical clinical manifestations of functional pituitary tumors caused by excessive hormone levels, some pituitary tumors are also accompanied by abnormal glucose metabolism. The effects of these seven hormones on glucose metabolism are important for the treatment of diabetes secondary to pituitary tumors. This review focuses on the effects of hormones on glucose metabolism, providing important clues for the diagnosis and treatment of related diseases.

Overexpression of IGF2 affects mouse weight and glycolipid metabolism and IGF2 is positively related to macrosomia

Objective

To investigate the effects of insulin-like growth factor 2 (IGF2) on growth and glycolipid metabolism, as well as the underlying mechanism.

Methods

A mouse model of IGF2 overexpression was constructed to measure weight gain before adulthood, to obtain the values of adult glycolipid metabolism indicators in the peripheral blood and to detect the expression of genes in the IGF2 signaling pathway in different mouse tissues. The present study also explored the independent association between the IGF2 gene and macrosomia by detecting and comparing the expression levels of IGF2 mRNA/H19 RNA in maternal peripheral blood and fetal cord blood of 26 human pregnancies.

Results

In the mouse model, weights of the IGF2-overexpressing mice were significantly higher than those of the control mice at the age of 5-10 weeks. The glucose concentration, total cholesterol and high-density lipoprotein cholesterol (HDL-C) levels of IGF2-overexpressing mice were significantly lower than those of wild-type (WT) mice. Compared with the WT mice, the expression of H19 was significantly decreased in the pancreas and IGF1R was significantly decreased in the muscle of mice with IGF2 overexpression. The expression levels of STAT3 and AKT2 showed significant decrease in liver, muscle and increase in muscle of IGF2-overexpressing mice, respectively. GLUT2 expression showed significant increase in liver, kidney, muscle and decrease in pancreas of mice with IGF2 overexpression. This study also found that in normal mothers with the similar clinical characteristics, IGF2 expression in the maternal peripheral blood and fetal cord blood is an independent factor influencing macrosomia.

Conclusion

IGF2 expression was independently correlated with the occurrence of macrosomia, and overexpression of IGF2 significantly increased the weights of mice at the age of 5-10 weeks and significantly affected the values of adult glycolipid metabolism indicators, which might be the result of changes in the IGF2-IGF1R-STAT3/AKT2-GLUT2/GLUT4 pathway. These findings might suggest that IGF2 plays an important role in growth and glycolipid metabolism during both pregnancy and postnatal development.

A network pharmacology study of mechanism and efficacy of Jiawei Huanglian-Wendan decoction in polycystic ovary syndrome with insulin resistance

Polycystic ovary syndrome (PCOS) is a common reproductive metabolic disorder, normally accompanied by insulin resistance (IR). The specific pathogenesis of this disease remains unclear. To identify the underlying pathogenesis of PCOS with IR and explore the potential efficacy and mechanism of Jiawei Huanglian-Wendan decoction (JHWD) by a network pharmacology approach. The effective components and the potential drug and disease-related targets are retrieved. Drug-disease overlapped targets are being obtained by Venny analysis. The construction of protein-protein interaction network relied on Search Tool for the Retrieval of Interacting Genes/Proteins database (STRING), after uploading drug-disease overlapped targets. The drug-component-target-disease interaction network map was displayed , after importing their data into Cytoscape 3.7.2 software. Bioinformatics analyses are being performed by Metascape and Kyoto Encyclopedia of Genes and Genomes databases, respectively. Further, molecular docking analysis was carried out using AutoDock software. Finally, the influence of JHWD is verified by means of traditional Chinese medicine syndrome score, the rate of resumption of normal menstrual cycles and regular ovulation, the blood lipid levels, the blood glucose and insulin levels, and the inflammatory cytokines in PCOS with IR patients. Four primary interaction networks of JHWD are constructed. The enrichment analysis of PCOS-IR-related targets demonstrated that the top enriched pathways in the development of PCOS with IR are pathways in cancer, metabolic, phosphoinositide-3-kinase-protein kinase B signaling, lipid and atherosclerosis, and mitogen-activated protein kinase signaling pathways. Molecular docking analysis revealed strong binding interactions of the key targets with the active components. Further confirmations showed that the active components of JHWD exhibited significant clinical efficacy in improving the clinical syndromes, menstrual cyclicity and ovulatory function, and significantly reducing the blood lipid levels, blood glucose and insulin levels, and inflammatory cytokines in PCOS with IR patients. The combination of the network pharmacological analysis and clinical validation stated that the active compounds in JHWD could regulate glycolipid metabolism, reduce IR, and exert anti-inflammatory effects in the treatment of PCOS with IR, promoting Chinese classical formulations.

Serum-Derived Exosomal microRNAs in Lipid Metabolism in Polycystic Ovary Syndrome

The crosstalk between obesity and insulin resistance (IR) in polycystic ovary syndrome (PCOS) may be related to miRNA regulation secreted by exosomes. However, the underlying mechanism remains to be explored. A model of PCOS with IR was constructed in mice with dehydroepiandrosterone (DHEA) and a high-fat diet (HFD). Serum exosomes were extracted and characterized using transmission electron microscopy (TEM) and western blot analysis (for CD9, CD63, and CD81). The expression of miR-20b-5p and miR-106a-5p in serum exosomes was detected by qRT-PCR. The effects of serum exosomal miR-20b-5p and miR-106a-5p on lipid metabolism and ovary histological structure in PCOS model with IR were also explored. Serum exosomal miR-20b-5p and miR-106a-5p overexpression could inhibit adipocyte differentiation in 3T3-L1 cells with IR and PCOS mice model. Furthermore, the predicted targets of miR-20b-5p and miR-106a-5p were also analyzed with bioinformatics. In DHEA + HFD serum-derived exosomes, the miR-20b-5p and miR-106a-5p levels were markedly decreased. Overexpression of miR-20b-5p and miR-106a-5p alleviated adipocyte differentiation-related genes and triglyceride content in 3T3-L1 cells and liver steatosis in mice. Bioinformatics analysis of miR-20b-5p and miR-106a-5p predicted targets indicated that miR-20b-5p and miR-106a-5p were highly related to lipid metabolism. Serum-derived exosome miR-20b-5p and miR-106a-5p inhibited adipocyte differentiation during the process of PCOS with IR, which might be a novel therapeutic target.

MicroRNA-21 promotes pancreatic β cell function through modulating glucose uptake

Pancreatic β cell dysfunction contributes to the pathogenesis of type 2 diabetes. MiR-21 has been shown to be induced in the islets of glucose intolerant patients and type 2 diabetic mice. However, the role of miR-21 in the regulation of pancreatic β cell function remains largely elusive. In the current study, we identify the pathway by which miR-21 regulates glucose-stimulated insulin secretion utilizing mice lacking miR-21 in their β cells (miR-21βKO). We find that miR-21βKO mice develop glucose intolerance due to impaired glucose-stimulated insulin secretion. Mechanistic studies reveal that miR-21 enhances glucose uptake and subsequently promotes insulin secretion by up-regulating Glut2 expression in a miR-21-Pdcd4-AP-1 dependent pathway. Over-expression of Glut2 in knockout islets results in rescue of the impaired glucose-stimulated insulin secretion. Furthermore, we demonstrate that delivery of miR-21 into the pancreas of type 2 diabetic db/db male mice is able to promote Glut2 expression and reduce blood glucose level. Taking together, our results reveal that miR-21 in islet β cell promotes insulin secretion and support a role for miR-21 in the regulation of pancreatic β cell function in type 2 diabetes.

Myoinositol Reduces Inflammation and Oxidative Stress in Human Endothelial Cells Exposed In Vivo to Chronic Hyperglycemia

Myo-inositol (Myo) improves insulin resistance, glucose metabolism, and helps gestational diabetes (GDM) management. GDM is associated with a pro-inflammatory state and increased oxidative stress, which are both involved in vascular damage in diabetes. Our aim was to study Myo anti-inflammatory/antioxidant potential effects on an in vitro model of human umbilical vein endothelial cells (HUVECs). To this end, monocyte cell adhesion to HUVECs, adhesion molecule membrane exposure, and oxidative stress levels were determined in cells from control (C-) and GDM women treated during pregnancy either with diet only (GD-) or with diet plus Myo (GD+Myo). To deeply study the vascular effects of Myo, the same evaluations were performed in C- and GD-HUVECs following 48 h in vitro stimulation with Myo. Notably, we first observed that GD-HUVECs obtained from women assuming Myo supplementation exhibited a significantly decreased number of monocytes that adhered to endothelial cells, less adhesion molecule exposure, and lower intracellular reactive oxygen species (ROS) levels in the basal state as compared to GD-HUVECs obtained from women treated by diet only. This Myo anti-inflammatory/antioxidant effect was confirmed by 48 h in vitro stimulation of GD-HUVECs as compared to controls. Altogether, these results strongly suggest that Myo may exert protective actions against chronic inflammation induced by endothelial dysfunction in diabetes.

MicroRNAs: The Link between the Metabolic Syndrome and Oncogenesis

Metabolic syndrome (MetS) represents a cluster of disorders that increase the risk of a plethora of conditions, in particular type two diabetes, cardiovascular diseases, and certain types of cancers. MetS is a complex entity characterized by a chronic inflammatory state that implies dysregulations of adipokins and proinflammatory cytokins together with hormonal and growth factors imbalances. Of great interest is the implication of microRNA (miRNA, miR), non-coding RNA, in cancer genesis, progression, and metastasis. The adipose tissue serves as an important source of miRs, which represent a novel class of adipokines, that play a crucial role in carcinogenesis. Altered miRs secretion in the adipose tissue, in the context of MetS, might explain their implication in the oncogenesis. The interplay between miRs expressed in adipose tissue, their dysregulation and cancer pathogenesis are still intriguing, taking into consideration the fact that miRNAs show both carcinogenic and tumor suppressor effects. The aim of our review was to discuss the latest publications concerning the implication of miRs dysregulation in MetS and their significance in tumoral signaling pathways. Furthermore, we emphasized the role of miRNAs as potential target therapies and their implication in cancer progression and metastasis.

Huangjinya Black Tea Alleviates Obesity and Insulin Resistance via Modulating Fecal Metabolome in High-Fat Diet-Fed Mice

SCOPE

Huangjinya is a light-sensitive tea mutant containing low levels of tea polyphenols. Currently, most studies focused on characteristics formation, free amino acid metabolism and phytochemical purification. The biological activity of Huangjinya black tea (HJBT) on metabolic syndrome regarding fecal metabolome modulation is unavailable and is studied herein.

METHODS AND RESULTS

High-fat diet (HFD)-fed mice are treated with HJBT for 9 weeks, various metabolic biomarkers and fecal metabolites are determined. HJBT reduces adipogenic and lipogenic gene expression, enhances lipolytic gene expression, decreases adipocyte expansion, and prevents the development of obesity. HJBT reduces lipogenic gene expression, increases fatty acid oxidation-related genes expression, which alleviates liver steatosis. HJBT enhances glucose/insulin tolerance, increases insulin/Akt signaling, attenuates hyperlipidemia and hyperglycemia, prevents the onset of insulin resistance. HJBT modulates bile acid metabolism, promotes secondary/primary bile acid ratio; increases short-chain fatty acids production, promotes saturated and polyunsaturated fatty acids content; reduces carnitines and phosphocholines, but increases myo-inositol content; decreases branched-chain and aromatic amino acids content; increases the metabolite content related to pentose phosphate pathway.

CONCLUSION

This study reported the association between fecal metabolome modulation and metabolism improvement due to HJBT administration, proposes HJBT as a dietary intervention for preventing obesity and metabolic disorders.

Serum Level of miR-1 and miR-155 as Potential Biomarkers of Stress-Resilience of NET-KO and SWR/J Mice

In the present study, we used three strains of mice with various susceptibility to stress: mice with knock-out of the gene encoding norepinephrine transporter (NET-KO), which are well characterized as displaying a stress-resistant phenotype, as well as two strains of mice displaying two different stress-coping strategies, i.e., C57BL/6J (WT in the present study) and SWR/J. The procedure of restraint stress (RS, 4 h) was applied, and the following behavioral experiments (the forced swim test and sucrose preference test) indicated that NET-KO and SWR/J mice were less sensitive to RS than WT mice. Then, we aimed to find the miRNAs which changed in similar ways in the serum of NET-KO and SWR/J mice subjected to RS, being at the same time different from the miRNAs found in the serum of WT mice. Using Custom TaqMan Array MicroRNA Cards, with primers for majority of miRNAs expressed in the serum (based on a preliminary experiment using the TaqMan Array Rodent MicroRNA A + B Cards Set v3.0, Thermo Fisher Scientific, Waltham, MA, USA) allowed the identification of 21 such miRNAs. Our further analysis focused on miR-1 and miR-155 and their targets—these two miRNAs are involved in the regulation of BDNF expression and can be regarded as biomarkers of stress-resilience.