cyclin-d1 and Diabetes-Mellitus--Type-2

SiJunZi decoction (SJZD), one of the traditional Chinese medicine formulas, has been clinically and traditionally used to improve glucose and lipid metabolism and promote bone remodeling.. To study the actions and mechanisms of SJZD on bone remodeling in a type 2 diabetes mouse model.. Diabetic mice generated with a high-fat diet (HFD) and streptozotocin (STZ) were subjected to SJZD treatment for 8 weeks. Blood glucose and lipid profile, redox status and bone metabolism were determined by ELISA or biochemical assays. Bone quality was evaluated by micro-CT, three-point bending assay and Fourier transform infrared spectrum (FTIR). Bone histomorphometry alterations were evaluated by Hematoxylin-Eosin (H&E), tartrate resistant acid phosphatase (TRAP) staining and Safranin O-fast green staining. The expressions of superoxide dismutase 1 (SOD1), advanced glycation end products (AGEs), receptor for advanced glycosylation end products (RAGE), phosphorylated nuclear factor kappa-B (p-NF-κB), NF-κB, cathepsin K, semaphorin 3A (Sema3A), insulin-like growth factor 1 (IGF1), p-GSK-3β, (p)-β-catenin, Runt-related transcription factor 2 (Runx2) and Cyclin D1 in the femurs and/or tibias were examined by Western blot or immunohistochemical staining. The main constituents in the SJZD aqueous extract were characterized by a HPLC/MS.. SJZD intervention improved glucose and lipid metabolism and preserved bone quality in the diabetic mice, in particular glucose tolerance, lipid profile, bone microarchitecture, strength and material composition. SJZD administration to diabetic mice preserved redox homeostasis in serum and bone marrow, and prevented an increase in AGEs, RAGE, p-NF-κB/NF-κB, cathepsin K, p-GSK-3β, p-β-catenin expressions and a decrease in Sema3A, IGF1, β-catenin, Runx2 and Cyclin D1 expressions in tibias and/or femurs. Thirteen compounds were identified in SJZD aqueous extract, including astilbin, liquiritin apioside, ononin, ginsenoside Re, Rg1, Rb1, Rb2, Ro, Rb3, Rd, notoginsenoside R2, glycyrrhizic acid, and licoricesaponin B2.. SJZD ameliorates bone quality in diabetic mice possibly via maintaining redox homeostasis. The mechanism governing these alterations are possibly related to effects on the AGEs/RAGE and Wnt/β-catenin signaling pathways. SJZD may offer a novel source of drug candidates for the prevention and treatment of type 2 diabetes and osteoporosis.

Topics: Animals; beta Catenin; Blood Glucose; Cathepsin K; Core Binding Factor Alpha 1 Subunit; Cyclin D1; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Glycation End Products, Advanced; Glycogen Synthase Kinase 3 beta; Homeostasis; Lipids; Mice; NF-kappa B; Oxidation-Reduction; Receptor for Advanced Glycation End Products; Semaphorin-3A; Wnt Signaling Pathway

To examine the effect of lncRNA Kcnq1ot1 on pancreatic β cells in the development of diabetes.. The expression levels of Kcnq1ot1 were detected in the islets of diabetes mouse models and the serum of patients with type 2 diabetes by qRT-PCR. CCK8, Ki67 staining, immunohistochemical analyses, glucose-stimulated insulin secretion and intraperitoneal glucose tolerance test were performed to detect the effect of Kcnq1ot1 on β-cell proliferation and insulin secretion in vitro and in vivo. The relationship between Kcnq1ot1 and miR-15b-5p was predicted by bioinformatics prediction, which was confirmed by luciferase reporter assay.. Kcnq1ot1 was more abundant in the pancreas. The expression of Kcnq1ot1 was decreased in the islets of db/db mice and diet-induced obese mice and in the serum of patients with type 2 diabetes. Silencing Kcnq1ot1 inhibited the β-cell proliferation concomitant with a reduction in the levels of Ccnd1 and Ccnd2. Insulin synthesis and secretion were impaired, along with the decreased expression of Ins1, Ins2, and insulin-related transcription factors. Moreover, Kcnq1ot1 knockdown in vivo reduced glucose tolerance and decreased insulin secretion, consistent with the reduction in the relative islet area and Ki67-positive β-cells detected by immunochemistry and immunofluorescence staining, respectively. Mechanistically, Kcnq1ot1 directly targeted miR-15b-5p which regulated β-cell proliferation and insulin secretion through Ccnd1 and Ccnd2. Notably, the suppression of miR-15b-5p attenuated the inhibition of Min6 proliferation and insulin production induced by Kcnq1ot1 knockdown.. Kcnq1ot1 regulated β-cell proliferation and insulin secretion via the miR-15b-5p/Ccnd1 and Ccnd2 axis, which is worthy of further investigation considering its potential in diabetes treatment.

Topics: Animals; Cell Proliferation; Cyclin D1; Cyclin D2; Diabetes Mellitus, Type 2; Down-Regulation; Glucose; Humans; Insulin Secretion; Insulin-Secreting Cells; Insulins; Ki-67 Antigen; Mice; MicroRNAs; Potassium Channels, Voltage-Gated

Obesity with dysfunctional adipose cells is the major cause of the current epidemic of type 2 diabetes (T2D). We examined senescence in human adipose tissue cells from age- and BMI-matched individuals who were lean, obese, and obese with T2D. In obese individuals and, more pronounced, those with T2D, we found mature and fully differentiated adipose cells to exhibit increased senescence similar to what we previously have shown in the progenitor cells. The degree of adipose cell senescence was positively correlated with whole-body insulin resistance and adipose cell size. Adipose cell protein analysis revealed dysfunctional cells in T2D with increased senescence markers reduced PPAR-γ, GLUT4, and pS473AKT. Consistent with a recent study, we found the cell cycle regulator cyclin D1 to be increased in obese cells and further elevated in T2D cells, closely correlating with senescence markers, ambient donor glucose, and, more inconsistently, plasma insulin levels. Furthermore, fully differentiated adipose cells were susceptible to experimentally induced senescence and to conditioned medium increasing cyclin D1 and responsive to senolytic agents. Thus, fully mature human adipose cells from obese individuals, particularly those with T2D become senescent, and SASP secretion by senescent progenitor cells can play an important role in addition to donor hyperinsulinemia.

Topics: Adipose Tissue; Biomarkers; Culture Media, Conditioned; Cyclin D1; Diabetes Mellitus, Type 2; Glucose; Humans; Insulin Resistance; Insulins; Obesity; Peroxisome Proliferator-Activated Receptors

Type 2 diabetes, which is mainly linked to obesity, is associated with increased incidence of liver cancer. We have previously found that in various models of obesity/diabetes, hyperinsulinemia maintains heightened hepatic expression of cyclin D1, suggesting a plausible mechanism linking diabetes and liver cancer progression. Here we show that cyclin D1 is greatly elevated in human livers with diabetes and is among the most significantly upregulated genes in obese/diabetic liver tumors. Liver-specific cyclin D1 deficiency protected obese/diabetic mice against hepatic tumorigenesis, whereas lean/nondiabetic mice developed tumors irrespective of cyclin D1 status. Cyclin D1 dependency positively correlated with liver cancer sensitivity to palbociclib, an FDA-approved CDK4 inhibitor, which was effective in treating orthotopic liver tumors under obese/diabetic conditions. The antidiabetic drug metformin suppressed insulin-induced hepatic cyclin D1 expression and protected against obese/diabetic hepatocarcinogenesis. These results indicate that the cyclin D1-CDK4 complex represents a potential selective therapeutic vulnerability for liver tumors in obese/diabetic patients. SIGNIFICANCE: Obesity/diabetes-associated liver tumors are specifically vulnerable to cyclin D1 deficiency and CDK4 inhibition, suggesting that the obese/diabetic environment confers cancer-selective dependencies that can be therapeutically exploited.

Topics: Animals; Antineoplastic Agents; Cyclin D1; Cyclin-Dependent Kinase 4; Diabetes Mellitus, Type 2; Hyperinsulinism; Hypoglycemic Agents; Liver Neoplasms, Experimental; Male; Metformin; Mice; Obesity; Piperazines; Protein Kinase Inhibitors; Pyridines; Up-Regulation

The mechanism underlying the increased susceptibility of type 2 diabetes in offspring of maternal malnutrition is poorly determined. Here we tested the hypothesis that functional microRNAs (miRNAs) mediated the maternal low-protein (LP) isocaloric diet induced pancreatic β-cell impairment. We performed miRNA profiling in the islets from offspring of LP and control diet mothers to explore the potential functional miRNAs responsible for β-cell dysfunction. We found that LP offspring exhibited impaired glucose tolerance due to decreased β-cell mass and insulin secretion. Reduction in the β-cell proliferation rate and cell size contributed to the decreased β-cell mass. MiR-15b was up-regulated in the islets of LP offspring. The up-regulated miR-15b inhibited pancreatic β-cell proliferation via targeting cyclin D1 and cyclin D2. Inhibition of miR-15b in LP islet cells restored β-cell proliferation and insulin secretion. Our findings demonstrate that miR-15b is critical for the regulation of pancreatic β-cells in offspring of maternal protein restriction, which may provide a further insight for β-cell exhaustion originated from intrauterine growth restriction.

Topics: Animals; Cell Line, Tumor; Cell Proliferation; Cyclin D1; Cyclin D2; Diabetes Mellitus, Type 2; Diet, Protein-Restricted; Female; Glucose Tolerance Test; Insulin; Insulin-Secreting Cells; Maternal Nutritional Physiological Phenomena; Mice; MicroRNAs; Pancreas; Pregnancy; Prenatal Exposure Delayed Effects

Bone regeneration disorders are a significant problem in patients with type 2 diabetes mellitus. Bone marrow stromal cells (BMSCs) are recognized as ideal seed cells for tissue engineering because they can stimulate osteogenesis during bone regeneration. Therefore, the aim of this study was to investigate the osteogenic potential of BMSCs derived from type 2 diabetic rats and the pathogenic characteristics of dysfunctional BMSCs that affect osteogenesis. BMSCs were isolated from normal and high-fat diet+streptozotocin-induced type 2 diabetic rats. Cell metabolic activity, alkaline phosphatase (ALP) activity, mineralization and osteogenic gene expression were reduced in the type 2 diabetic rat BMSCs. The expression levels of Wnt signaling genes, such as β-catenin, cyclin D1 and c-myc, were also significantly decreased in the type 2 diabetic rat BMSCs, but the expression of GSK3β remained unchanged. The derived BMSCs were cultured on calcium phosphate cement (CPC) scaffolds and placed subcutaneously into nude mice for eight weeks; they were detected at a low level in newly formed bone. The osteogenic potential of the type 2 diabetic rat BMSCs was not impaired by the culture environment, but it was impaired by inhibition of the Wnt signaling pathway, likely due to an insufficient accumulation of β-catenin rather than because of GSK3β stimulation. Using BMSCs derived from diabetic subjects could offer an alternative method of regenerating bone together with the use of supplementary growth factors to stimulate the Wnt signaling pathway.

Topics: Alkaline Phosphatase; Animals; Bone Marrow Cells; Calcium Phosphates; Cyclin D1; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Diet, High-Fat; Gene Expression Regulation; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Male; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Mice; Mice, Nude; Osteogenesis; Primary Cell Culture; Proto-Oncogene Proteins c-myc; Rats; Rats, Sprague-Dawley; Streptozocin; Transplantation, Heterologous; Wnt Signaling Pathway

The alteration of the beta-cell population in the Goto-Kakizaki rat (GK/Par line), a model of spontaneous type 2 diabetes, has been ascribed to significantly decreased beta-cell replication and neogenesis, while beta-cell apoptosis is surprisingly not enhanced and remains in the normal range. To gain insight into the mechanisms by which those beta-cells are protected from death, we studied ex vivo the apoptotic activity and the expression of a large set of pro/antiapoptotic and pro/antioxidant genes in GK/Par islet cells. This was done in vitro in freshly isolated islets as well as in response to culture conditions and calibrated reactive oxygen species (ROS) exposure (i.e., H2O2). We also investigated the intracellular mechanisms of the diabetic beta-cell response to ROS, the role if any of the intracellular cAMP metabolism, and finally the kinetic of ROS response, taking advantage of the GK/Par rat normoglycemia until weaning. Our results show that the peculiar GK/Par beta-cell phenotype was correlated with an increased expression of a large panel of antioxidant genes as well as pro/antiapoptotic genes. We demonstrate that such combination confers resistance to cytotoxic H2O2 exposure in vitro, raising the possibility that at least some of the activated stress/defense genes have protective effects against H2O2-triggered beta-cell death. We also present some evidence that the GK/Par beta-cell resistance to H2O2 is at least partly cAMP dependent. Finally, we show that such a phenotype is not innate but is spontaneously acquired after diabetes onset as the result of an adaptive response to the diabetic environment.

Topics: Adaptation, Physiological; Animals; Apoptosis; Apoptosis Regulatory Proteins; Cell Division; Cells, Cultured; Cyclic AMP; Cyclin D1; Diabetes Mellitus, Type 2; Disease Models, Animal; Heme Oxygenase-1; Hydrogen Peroxide; Hypoxia-Inducible Factor 1, alpha Subunit; Insulin-Secreting Cells; Male; Oxidants; Proto-Oncogene Proteins c-myc; Rats; Rats, Mutant Strains; Rats, Wistar; Reactive Oxygen Species; RNA, Messenger

We have previously shown that fenofibrate, a peroxisome proliferator-activated receptor-alpha activator, increases renal cytochrome P450 (CYP)-derived eicosanoids and improves endothelial function in pre-diabetic obese rats. The present study was designed to explore the efficacy of fenofibrate on blood pressure and renal injury in the advanced stage of type-2 diabetes. 26-week-old male Zucker diabetic fatty rats (ZDF) were fed fenofibrate (100 mg/kg/day) for 6 weeks. Chronic treatment with fenofibrate normalized systolic blood pressure and reduced glomerular size by 19% in diabetic rats. Western blot and fluorescent immunostaining revealed that the over-expression of collagen type IV and alpha-smooth muscle actin was significantly attenuated in the kidney of fenofibrate-treated ZDF (F-ZDF) rats. In addition, fenofibrate administration dramatically decreased the cyclin D1 protein level in the kidney of diabetic rats. In contrast, renal CYP2C23 and CYP4A proteins were significantly increased in F-ZDF rats. These fenofibrate effects were observed in the absence of significant changes in glucose, insulin or lipid levels. Taken together, our results demonstrate that fenofibrate may lower blood pressure and attenuate glomerular hypertrophy and collagen accumulation through the downregulation of cyclin D1 and upregulation of CYP monooxygenases in the late stage of type-2 diabetes.

Topics: Actins; Animals; Blood Pressure; Blotting, Western; Collagen Type IV; Cyclin D1; Cytochrome P-450 CYP2J2; Cytochrome P-450 CYP4A; Cytochrome P-450 Enzyme System; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Enzyme Induction; Fenofibrate; Hypertrophy; Hypolipidemic Agents; Immunohistochemistry; Kidney; Kidney Glomerulus; Male; PPAR alpha; Rats; Rats, Zucker

Liver injury initiated by non-lethal doses of CCl(4) and thioacetamide (TA) progresses to hepatic failure and death of type 2 diabetic (DB) rats due to failed advance of liver cells from G(0)/G(1) to S-phase and inhibited tissue repair. Objective of the present study was to investigate cellular signaling mechanisms of failed cell division in DB rats upon hepatotoxicant challenge. In CCl(4)-treated non-diabetic (non-DB) rats, increased IL-6 levels, sustained activation of extracellular regulated kinases 1/2 (ERK1/2) MAPK, and sustained phosphorylation of retinoblastoma protein (p-pRB) via cyclin D1/cyclin-dependent kinase (cdk) 4 and cyclin D1/cdk6 complexes stimulated G(0)/G(1) to S-phase transition of liver cells. In contrast to the non-DB rats, CCl(4) administration led to lower plasma IL-6, decreased ERK1/2 activation, lower cyclin D1, and cdk 4/6 expression resulting in decreased p-pRB and inhibition of liver cell division in the DB rats. Furthermore, higher TGFbeta1 expression and p21 activation may also contribute to decreased p-pRB in DB rats compared to non-DB rats. Similarly, after TA administration to DB rats, down-regulation of cyclin D1 and p-pRB leads to markedly decreased advance of liver cells from G(0)/G(1) to S-phase and tissue repair compared to the non-DB rats. Hepatic ATP levels did not differ between the DB and non-DB rats obviating its role in failed tissue repair in the DB rats. In conclusion, decreased p-pRB may contribute to blocked advance of cells from G(0)/G(1) to S-phase and failed cell division in DB rats exposed to CCl(4) or TA, leading to progression of liver injury and hepatic failure.

Topics: Adenosine Triphosphate; Animals; Carbon Tetrachloride Poisoning; Cell Cycle; Chemical and Drug Induced Liver Injury; Cyclin D1; Cyclin-Dependent Kinases; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Enzyme Activation; Extracellular Signal-Regulated MAP Kinases; Immunoblotting; Interleukin-6; Liver Diseases; Male; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Rats; Rats, Sprague-Dawley; Retinoblastoma Protein; Thioacetamide; Transforming Growth Factor beta1