Gene expression in the pathophysiology of type 2 diabetes mellitus

The role of m6A and m6Am RNA modifications in the pathogenesis of diabetes mellitus

The rapidly developing research field of epitranscriptomics has recently emerged into the spotlight of researchers due to its vast regulatory effects on gene expression and thereby cellular physiology and pathophysiology. N⁶-methyladenosine (m⁶A) and N⁶,2'-O-dimethyladenosine (m⁶Am) are among the most prevalent and well-characterized modified nucleosides in eukaryotic RNA. Both of these modifications are dynamically regulated by a complex set of epitranscriptomic regulators called writers, readers, and erasers. Altered levels of m⁶A and also several regulatory proteins were already associated with diabetic tissues. This review summarizes the current knowledge and gaps about m⁶A and m⁶Am modifications and their respective regulators in the pathophysiology of diabetes mellitus. It focuses mainly on the more prevalent type 2 diabetes mellitus (T2DM) and its treatment by metformin, the first-line antidiabetic agent. A better understanding of epitranscriptomic modifications in this highly prevalent disease deserves further investigation and might reveal clinically relevant discoveries in the future.

Restrictive Pulmonary Disease in Diabetes Mellitus Type II Patients

Background

The present study aimed to evaluate the proportion of restrictive pulmonary disease in individuals with diabetes mellitus type II patients.

Methodology

A cross-sectional study was performed at Liaquat University of Medical & Health Sciences between May 2020 and June 2021. All individuals aged between 40 and 65 years, irrespective of gender were included in the study. While those individuals with known obstructive lung diseases, blood disorders, or malignancy were excluded. Spirometry, total lung capacity (TLC), and carbon monoxide diffusing capacity (DLCO) measurements were conducted to obtain a pattern of restrictive disease in patients. Patients were divided into three main groups; i) prediabetes, ii) newly diagnosed cases of diabetes, iii) longstanding diabetes mellitus type II, and iv) control group. The parameters like the patients’ age, sex, medication, history of smoking, and cardiac diseases, among other demographics were recorded. The data collected was recorded on a predesigned proforma.

Results

The majority of the newly diagnosed cases, as well as long-standing diseases, were elderly males (p=0.014 and p<0.0001). Dyspnea was significantly correlated with longstanding diabetes mellitus type II as indicated by a higher mean score of 0.65 ± 0.10 (p=0.006). Smoking did not significantly correlate with diabetes mellitus type II. In patients with longstanding diabetes, 27 (14.4%) had a modified Medical Research Council (mMRC) score of greater than two while none of the controls had severe breathlessness. Reduced forced vital capacity (FVC) was detected in 16.0% of patients with longstanding diabetes and 12.8% in patients with newly diagnosed disease. Similar results were obtained for total lung capacity (TLC) and diffusing capacity (DLCO) (p=0.003 and p=0.02).

Conclusion

Diabetes mellitus type II is significantly associated with restrictive lung disease in patients as indicated by a high number of patients with longstanding diabetes in our study who were found to have restrictive lung disease and severe dyspnea. Screening for lung dysfunction could aid in optimum management of this debilitating disease.

The effects of two iso-volume endurance training protocols on mitochondrial dysfunction in type 2 diabetic male mice

Purpose

Type 2diabetes(T2D) is one of the more common diseases in the world and has been widely spread. One of the suggested mechanisms in development of T2D, is mitochondrial dysfunction. The purpose of this study is to compare the effects of two endurance training protocols with low and moderate intensity on biogenesis and mitochondrial function, in Diabetic mice induced by high fat diet and Streptozotocin(STZ).

Methods

40 five week old mice divided to four groups including: health control (HC, n = 7), diabetic control (DC, n = 7), low endurance training (DLT, n = 7) and moderate endurance training (DMT, n = 7). DMT group ran at 5 m/min for an hour, 3 days a week on a treadmill, and DLT group ran at 3 m/min for an hour, 5 days a week on a treadmill for 8 weeks.

Results

The cytosolic content of PGC1α, Tfam and mitochondrial content of citrate synthase(Cs) and cytochrome c oxidase(Cox) in DC was significantly reduced compared to HC(P˂0.05). All of the parameters except for Cs in both DLT and DMT were increased compared to DC (P˂0.05), but there was no difference between them and the HC (P˃0.05). There was no difference in Cs enzyme between the DC and the DLT(P˃0.05), but it was significantly increased in the DMT(P˂0.05). There was a significantly difference between Cs enzyme in HC and DLT(P˂0.05), but there wasn't any significant difference between HC and DMT(P˃0.05).

Conclusions

The results showed that in same volume condition, both endurance training protocols improved the proteins involved in biogenesis and mitochondrial function in T2D mice and there was no significant difference between them.

Hyssopus officinalis exerts hypoglycemic effects on streptozotocin-induced diabetic rats via modulating GSK-3β, C-fos, NF-κB, ABCA1 and ABGA1 gene expression

Objectives

Type 2 diabetes mellitus (DMT2) is contributed to dual interactions between environmental factors and certain genetic factors. This impressed a great need for novel treatment strategy. Nevertheless, Hyssopus officinalis (H. officinalis) as a terrestrial herb is considered to be an important source of natural antioxidants, it could be assessed as an anti-hyperglycemic agent.

Methods

In the current study, HPLC identified the active constitutes of H. officinalis, including total polyphenols, and flavonoids. Type 2 diabetes mellitus was induced in male Wistar albino rats via a single ip dose of streptozotocin (STZ) (35 mg/kg BW). One week post diabetes induction, rats were administrated H. officinalis (500 mg/ kg BW) orally for one month. Molecular analysis was assessed to investigate the efficiency of H. officinalis on modulating ATP-binding cassette transporter A1 (ABCA1) and G1 (ABCG1) genes, in addition to apoptotic biomarkers, glycogen synthase kinase-3β (GSK-3β) and cellular oncogene-fos (C-fos) genes. Furthermore, inflammatory biomarkers, nuclear factor kappa-B (NF-κB) and tumor necrosis factor-α (TNF-α) gene expression were also assessed.

Results

H. officinalis alcoholic extract declared the presence of polyphenols as gallic acid and flavonoids as quercetin in addition to many active constituents. Apigenin-7-glucoside and Chlorgenic acid were the most common constituents in the extract. RT-PCR results declared a significant up-regulation in mRNA gene expression of ABCA1 and ABCG1 upon H. officinalis treatment. Meanwhile, C-fos gene expression recorded a slight down-regulation. Gene expression of apoptotic biomarker GSK-3β demonstrated a significant down regulation as well as inflammatory biomarkers NF-κB and TNF-α.

Conclusion

From the data recorded, it could be concluded that H. officinalis exerts a great hypoglycemic potential via modulating C-fos, GSK-3β, NF-κB, TNF-α, ABCA1 and ABCG1 gene expression and signaling pathways and could be considered as an effective candidate for DMT2 treatment.

Multi-dimensional Transcriptional Remodeling by Physiological Insulin In Vivo

Regulation of gene expression is an important aspect of insulin action but in vivo is intertwined with changing levels of glucose and counter-regulatory hormones. Here we demonstrate that under euglycemic clamp conditions, physiological levels of insulin regulate interrelated networks of more than 1,000 transcripts in muscle and liver. These include expected pathways related to glucose and lipid utilization, mitochondrial function, and autophagy, as well as unexpected pathways, such as chromatin remodeling, mRNA splicing, and Notch signaling. These acutely regulated pathways extend beyond those dysregulated in mice with chronic insulin deficiency or insulin resistance and involve a broad network of transcription factors. More than 150 non-coding RNAs were regulated by insulin, many of which also responded to fasting and refeeding. Pathway analysis and RNAi knockdown revealed a role for lncRNA Gm15441 in regulating fatty acid oxidation in hepatocytes. Altogether, these changes in coding and non-coding RNAs provide an integrated transcriptional network underlying the complexity of insulin action.

The altered renal and hepatic expression of solute carrier transporters (SLCs) in type 1 diabetic mice

Diabetes mellitus is a chronic metabolic disorder that significantly affects human health and well-being. The Solute carrier transporters (SLCs), particularly the Organic anion/cation transporters (Oats/Octs/Octns), Organic anion transporting polypeptides (Oatps) and Oligopeptide transporters (Pepts) are essential membrane proteins responsible for cellular uptake of many endogenous and exogenous substances such as clinically important drugs. They are widely expressed in mammalian key organs especially the kidney and liver, in which they facilitate the influx of various drug molecules, thereby determining their distribution and elimination in body. The altered expression of SLCs in diabetes mellitus could have a profound and clinically significant influence on drug therapies. In this study, we extensively investigated the renal and hepatic expression of twenty essential SLCs in the type 1 diabetic Ins2Akita murine model that develops both hyperglycemia and diabetes-related complications using real-time PCR and immunoblotting analysis. We found that the renal expression of mOatp1a1, mOatp1a6, mOat1, mOat3, mOat5, mOct2 and mPept2 was decreased; while that of mPept1 was increased at the mRNA level in the diabetic mice compared with non-diabetic controls. We found up-regulated mRNA expression of mOatp1a4, mOatp1c1, mOctn2, mOct3 and mPept1 as well as down-regulation of mOatp1a1 in the livers of diabetic mice. We confirmed the altered protein expression of several SLCs in diabetic mice, especially the decreased renal and hepatic expression of mOatp1a1. We also found down-regulated protein expression of mOat3 and mOctn1 in the kidneys as well as increased protein expression of mOatp1a4 and mOct3 in the livers of diabetic mice. Our findings contribute to better understanding the modulation of SLC transporters in type 1 diabetes mellitus, which is likely to affect the pharmacokinetic performance of drugs that are transported by these transporters and therefore, forms the basis of future therapeutic optimization of regimens in patients with type 1 diabetes mellitus.

Relationship among circulating inflammatory proteins, platelet gene expression, and cardiovascular risk

OBJECTIVE

Cardiovascular disease is a complex disorder influenced by interactions of genetic variants with environmental factors. However, there is no information from large community-based studies examining the relationship of circulating cell-specific RNA to inflammatory proteins. In light of the associations among inflammatory biomarkers, obesity, platelet function, and cardiovascular disease, we sought to examine the relationships of C-reactive protein (CRP) and interleukin-6 (IL-6) to the expression of key inflammatory transcripts in platelets.

APPROACH AND RESULTS

We quantified circulating levels of CRP and IL-6 in 1625 participants of the Framingham Heart Study (FHS) Offspring cohort examination 8 (mean age, 66.6 ± 6.6 years; 46% men). We measured the expression of 15 relevant genes by high-throughput quantitative reverse transcriptase polymerase chain reaction from platelet-derived RNA and used multivariable regression to relate serum concentrations of CRP and IL-6 with gene expression. Levels of CRP and IL-6 were associated with 10 of the 15 platelet-derived inflammatory transcripts, ALOX5, CRP, IFIT1, IL6, PTGER2, S100A9, SELENBP1, TLR2, TLR4, and TNFRSF1B (P<0.001). Associations between platelet mRNA expression with CRP and IL-6 persisted after multivariable adjustment for potentially confounding factors. Six genes positively associated with CRP or IL-6 in the FHS sample were also upregulated in megakaryocytes in response to CRP or IL-6 exposure.

CONCLUSIONS

Our data highlight the strong connection between the circulating inflammatory biomarkers CRP and IL-6 and platelet gene expression, adjusting for cardiovascular disease risk factors. Our results also suggest that body weight may directly influence these associations.

Parenteral nutrition and preOp preparation in prevention of post-operative insulin resistance in gastrointestinal carcinoma

PURPOSE

The aim was to compare preventive effect of total parenteral nutrition (TPN) and oral nutrition (preOp) on the perioperative insulin resistance prevention in surgical gastrointestinal cancer patients.

MATERIAL/METHODS

The study was conducted in a group of 75 elective gastric and large intestine cancer patients. Patients were randomly divided into 3 study groups, 25 patients each: group I (NIL) - no preparations influencing tissue sensitivity to insulin, group II (TPN) - total parenteral nutrition in its preoperative stage and group III (TPN + preOp) parenteral nutrition and preOp in the preoperative phase.

RESULTS

Immediately after the surgery, no statistically significant differences in insulin resistance level between groups were observed. During the first 6 postoperative hours, a statistically significant decrease of insulin resistance level in the TPN+ preOp group in comparison to others, was observed. During the first 24 postoperative hours, the NIL group was the only one to keep the insulin resistance level the same as in the preoperative phase.

CONCLUSIONS

Application of TPN in the preoperative phase leads to shortening of perioperative insulin resistance time. Combining TPN with oral application of carbohydrate before surgical procedure is an effective and the best method in postoperative insulin resistance syndrome prevention.

Cross-sectional and prospective study of lung function in adults with type 2 diabetes: the Atherosclerosis Risk in Communities (ARIC) study

OBJECTIVE

The aim of this study was to test the hypothesis that diabetes is independently associated with reduced lung function, both cross-sectionally and longitudinally.

RESEARCH DESIGN AND METHODS

We conducted cross-sectional and prospective analyses of diabetes status and lung function decline using baseline and 3-year follow-up data on 1,100 diabetic and 10,162 nondiabetic middle-aged adults from the Atherosclerosis Risk in Communities (ARIC) Study. Forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV(1)) were measured at baseline and at the 3-year follow-up using standard spirometry.

RESULTS

At baseline, adults with diabetes had significantly lower predicted FVC (96 vs. 103%, P < 0.001) and predicted FEV(1) (92 vs. 96%, P < 0.001) than those without diabetes. These differences remained significant after adjustment for demographic characteristics, adiposity, smoking, physical activity index, education, and ARIC field center. Graded, inverse associations were observed between hyperglycemia, diabetes severity (i.e., duration of diabetes and types of antidiabetes medications), and FVC and FEV(1) (all P(trend) < 0.001). In prospective analyses, FVC declined faster in diabetic adults than in their nondiabetic counterparts (64 vs. 58 ml/year, P = 0.01). Diabetes severity as indicated by intensity of antidiabetic treatment also showed graded relationships with the rate of FVC decline (P < 0.01).

CONCLUSIONS

These data support the notion that the lung is a target organ for diabetic injury. Additional research is required to identify pathophysiologic mechanisms and to determine clinical significance.

Reduced NO synthesis and eNOS mRNA expression in endothelial cells from newborns with a strong family history of type 2 diabetes

BACKGROUND

A deficient synthesis of nitric oxide (NO) may play a role in the early endothelial dysfunction of healthy humans with a strong family history of type 2 diabetes (DM2). In this study, we evaluate the intracellular synthesis of NO and the expression of eNOS transcripts in human umbilical vein endothelial cells (HUVECs), exposed to high glucose concentrations, of healthy newborns with (experimental) and without (control) a strong family history of DM2.

METHODS

HUVECs were incubated in M-199 culture media (containing a 5 mmol/L physiological glucose concentration) or supraphysiological glucose concentrations (15 or 30 mmol/L), for 48 h. Flow cytometry, reactive of Griess and RT-PCR were used to determine intracellular NO synthesis, presence of NO metabolites, and expression of eNOS, GLUT1 or p53 transcripts.

RESULTS

NO synthesis in experimental HUVECs showed a progressive reduction in the presence of increasing glucose concentration (11% for 5 mmol to 8% for 30 mmol; p < 0.01), whereas control HUVECs showed an increase in NO synthesis (3% for 5 mmol to 31% for 30 mmol; p < 0.001). In experimental HUVECs, we found a diminished expression of eNOS and p53, and also an enhanced expression of GLUT1 mRNA transcripts. Control HUVECs showed an increase in eNOS, and no modifications in p53 or GLUT1 mRNA transcripts.

CONCLUSIONS

Our results show how HUVECs, isolated from healthy newborns with a strong family history of DM2, have an abnormal intracellular synthesis of NO and an impaired expression of eNOS, GLUT1 and p53 genes, all associated with NO synthesis.