Evaluation of microRNA-192 in patients with diabetic nephropathy

MiRNAs as biomarkers of nutritional therapy to achieve T2DM remission in patients with coronary heart disease: from the CORDIOPREV study

BACKGROUND

Type 2 diabetes mellitus (T2DM) is currently a major global public health problem. Although disease remission is possible, few biomarkers have been identified which can help us select the diet that best promotes remission. Our aim was to study the potential of miRNAs as a tool to apply the Mediterranean diet or the low-fat diet in order to achieve T2DM remission in patients with coronary heart disease.

METHODS

From the CORDIOPREV study (n = 1002), a prospective, randomized, single-blind, controlled dietary intervention trial, all patients newly diagnosed with T2DM (n = 190) at baseline were included in the present study. Of these, after adhering to a low fat or Mediterranean diet for 60 months, 73 patients showed T2DM remission (Responders) and 110 continued with the disease (Non-responders). Plasma levels of 56 miRNAs were determined by RT-PCR. Generalized linear model, ROC curves and COX regression analyses were performed.

RESULTS

We observed that patients with low baseline plasma levels of miR-let7b-3p showed a high probability of T2DM remission after the consumption of a low-fat diet. In addition, patients with high levels of miR-141-5p, miR-182, and miR-192 at baseline showed a high probability of T2DM remission after following the Mediterranean diet. Scores built using miRNAs and clinical variables showed that high levels of a low-fat diet score and a high Mediterranean diet score were associated with a high probability of T2DM remission.

CONCLUSION

MiRNAs could be used as a tool for selecting the most efficient nutritional therapy (mediterranean or low-fat diet) to achieve T2DM remission in patients with coronary heart disease.

Novel therapeutic target for diabetic kidney disease through downregulation of miRNA-192-5p and miRNA-21-5p by celastrol: implication of autophagy, oxidative stress, and fibrosis

One of the most common microvascular effects of diabetes mellitus (DM) that may result in end-stage renal failure is diabetic kidney disease (DKD). Current treatments carry a substantial residual risk of disease progression regardless of treatment. By modulating various molecular targets, pentacyclic triterpenoid celastrol has been found to possess curative properties in the treatment of diabetes and other inflammatory diseases. Therefore, the present study investigated whether celastrol has anti-inflammatory, antioxidant, and antifibrotic effects as a natural compound against experimental DKD. Streptozotocin (55 mg/kg) was utilized for inducing DKD in a rat model. Antioxidant enzymes and renal function tests were assessed in serum samples. In kidney homogenate, relative miRNA-192-5p and miRNA-21-5p gene expressions were measured. Furthermore, using real-time PCR to evaluate the gene expressions of nucleus erythroid 2-related factor-2 (Nrf-2), matrix metalloproteinase-2 (MMP-2), proapoptotic caspase-3, antiapoptotic Bcl-2, LC-3, and Beclin-1. Moreover, the transforming growth factor β1 (TGF-β1), LC-3, Bcl-2, caspase-3 and NADPH oxidase 4 (NOX4) renal expressions were assessed semi-quantitatively using immunohistochemistry. Seven weeks of celastrol (1.5 mg/kg/day) treatment significantly ameliorated DKD. Celastrol improves kidney functions. Moreover, celastrol treatment demonstrated potent antioxidant effect. The mechanism of apoptosis resulting from the administration of celastrol included the modulation of Bcl-2 and caspase-3 expression in the kidney. Celasterol administration leads to an increase in LC-3 and Beclin-1 renal expression that resulting in autophagy. Celastrol treatment improved renal fibrosis by decreasing TGF-β1 and MMP-2 renal expression. These antifibrotic effects could be due to their ability to inhibit miRNA-192-5p and miRNA-21-5p expression in renal tissues. Celastrol exerts a renoprotective effect by targeting miRNA-21 and miRNA-192, as well as their downstream pathways, such as autophagy, apoptosis, and fibrosis.

Deciphering the role of MicroRNAs in diabetic nephropathy: Regulatory mechanisms and molecular insights

A serious consequence of diabetes mellitus, diabetic nephropathy (DN) which causes gradual damage to the kidneys. Dietary changes, blood pressure control, glucose control, and hyperlipidemia are all important components of DN management. New research, however, points to microRNAs (miRNAs) as having a pivotal role in DN pathogenesis. Miniature non-coding RNA molecules such as miRNAs control gene expression and impact several biological processes. The canonical and non-canonical routes of miRNA biogenesis are discussed in this article. In addition, several important signaling pathways are examined in the study of miRNA regulation in DN. A deeper knowledge of these regulatory mechanisms would allow for a better understanding of the molecular basis of DN and the development of innovative therapeutic strategies. Finally, miRNAs show tremendous potential as DN diagnostic biomarkers and treatment targets, opening up promising avenues for further study and potential clinical use.

Circulating miRNAs in Type 2 Diabetic Patients with and without Albuminuria in Malaysia

INTRODUCTION

Diabetic kidney disease (DKD) remains the leading cause of chronic kidney disease. Dysregulation of circulating miRNAs has been reported, suggesting their pathological roles in DKD. This study aimed to investigate differentially expressed miRNAs in the sera of type 2 diabetes mellitus (T2DM) patients with and without albuminuria in a selected Malaysian population.

METHOD

Forty-one T2DM patients on follow-up at a community clinic were divided into normo-(NA), micro-(MIC), and macroalbuminuria (MAC) groups. Differential levels of miRNAs in 12 samples were determined using the pathway-focused (human fibrosis) miScript miRNA qPCR array and was validated in 33 samples, using the miScript custom qPCR array (CMIHS02742) (Qiagen GmbH, Hilden, Germany).

RESULTS

Trends of upregulation of 3 miRNAs in the serum, namely, miR-874-3p, miR-101-3p, and miR-145-5p of T2DM patients with MAC compared to those with NA. Statistically significant upregulation of miR-874-3p (p = 0.04) and miR-101-3p (p = 0.01) was seen in validation cohort. Significant negative correlations between the estimated glomerular filtration rate (eGFR) and miR-874-3p (p = 0.05), miR-101-3p (p = 0.03), and miR-145-5p (p = 0.05) as well as positive correlation between miR-874-3p and age (p = 0.03) were shown by Pearson's correlation coefficient analysis.

CONCLUSION

Upregulation of previously known miRNA, namely, miR-145-5p, and possibly novel ones, namely, miR-874-3p and miR-101-3p in the serum of T2DM patients, was found in this study. There was a significant correlation between the eGFR and these miRNAs. The findings of this study have provided encouraging evidence to further investigate the putative roles of these differentially expressed miRNAs in DKD.

TGF-Beta as a Master Regulator of Diabetic Nephropathy

Diabetic nephropathy (DN) is one of the most common complications in diabetes mellitus and the leading cause of end-stage renal disease. TGF-β is a pleiotropic cytokine and has been recognized as a key mediator of DN. However, anti-TGF-β treatment for DN remains controversial due to the diverse role of TGF-β1 in DN. Thus, understanding the regulatory role and mechanisms of TGF-β in the pathogenesis of DN is the initial step towards the development of anti-TGF-β treatment for DN. In this review, we first discuss the diverse roles and signaling mechanisms of TGF-β in DN by focusing on the latent versus active TGF-β1, the TGF-β receptors, and the downstream individual Smad signaling molecules including Smad2, Smad3, Smad4, and Smad7. Then, we dissect the regulatory mechanisms of TGF-β/Smad signaling in the development of DN by emphasizing Smad-dependent non-coding RNAs including microRNAs and long-non-coding RNAs. Finally, the potential therapeutic strategies for DN by targeting TGF-β signaling with various therapeutic approaches are discussed.