Aerobic exercise leads to upregulation of Mir-126 and angiogenic signaling in the heart tissue of diabetic rats

Effect of diabetes on efferocytosis process

Diabetes is a complex of genetic, metabolic, and autoimmune disorders that are characterized by hyperglycemia. Elevated apoptotic cell count following defective clearance of dead cells that can cause chronic inflammation is a hallmark of the diabetic wound. Effective dead cell clearance is a prerequisite for rapid inflammation resolution and successful recovery. Efferocytosis is a multistep process in which phagocytes engulf the dead cells. Cell body elimination is of great significance in disease and homeostasis. Recent research has clarified that diabetic wounds have an enhanced load of the apoptotic cell, which is partly attributed to the dysfunction of macrophages in apoptotic clearance at the site of the diabetic wounds. In the current work, we highlight the pathways implicated in efferocytosis, from the diagnosis of apoptotic cells to the phagocytic swallowing and the homeostatic resolution, and explain the possible pathophysiological episodes occurring when the proceeding is abrogated. Also, we describe the last development in the management of inflammation in diabetes wound and future directions of surveillance.

Investigation of expression of myocardial miR-126, miR-29a and miR-222 as a potential marker in STZ- induced diabetic rats following interval and continuous exercise training

Purpose

Cardiac miRNAs are the recently discovered key modulators of gene expression in the heart which have been shown to contribute to both transcriptional and post-transcriptional regulation in diabetic cardiomyopathy. The aim of this study was to evaluate the protective effects of interval and continuous aerobic training on diabetic hearts by examining the expression of myocardial miR-126, miR-222 and miR-29a genes.

Methods

Thirty male wistar rats (200 ± 20 g) were randomly divided into six groups of healthy control (HC), diabetes control (DC), continuous training (CT), interval training (IT), continuous training with diabetes (CTD), and interval training with diabetes (ITD). Nicotinamide and Streptozotocin (STZ) were injected to induce type 2 diabetes. CT was performed with a speed of 10 to 22 m/min and 20 to 30 min and IT was performed with 10 to 39 m/min and total time of 15 min, five sessions per week for 6 weeks. Muscle expression of miR-126, miR-29a and miR-222 was determined by the RT-PCR method.

Results

The results show that gene expression of miR-126 was higher in IT (p < 0.01) compare to other groups. Also expression of miR-126 was higher in the CT compare to DC (p < 0.05) group. Gene expression of miR-222 was higher in aerobic groups than other groups (p < 0.01). Also expression of miR-222 was higher in ITD compare to the DC and CTD (p < 0.01) groups. Expression of miR-29a gene was higher in the aerobic groups compare to other groups. Also miR-29a was higher in the IT compare to CT (p < 0.01) group.

Conclusion

Diabetes decreased the expression of genes associated with the development of cardiac function. It seems that IT played a more effective role in cardiac protection than CT through higher miR-126, miR-222 and miR-29a gene expression.

MicroRNAs and Efferocytosis: Implications for Diagnosis and Therapy

About 10-100 billion cells are generated in the human body in a day, and accordingly, 10-100 billion cells predominantly die for maintaining homeostasis. Dead cells generated by apoptosis are also rapidly engulfed by macrophages (Mθs) to be degraded. In case of the inefficient engulfment of apoptotic cells (ACs) via Mθs, they experience secondary necrosis and thus release intracellular materials, which display damage-associated molecular patterns (DAMPs) and result in diseases. Over the last decades, researchers have also reflected on the significant contribution of microRNAs (miRNAs) to autoimmune diseases through the regulation of Mθs functions. Moreover, miRNAs have shown intricate involvement with completely adjusting basic Mθs functions, such as phagocytosis, inflammation, efferocytosis, tumor promotion, and tissue repair. In this review, the mechanism of efferocytosis containing "Find-Me", "Eat-Me", and "Digest-Me" signals is summarized and the biogenesis of miRNAs is briefly described. Finally, the role of miRNAs in efferocytosis is discussed. It is concluded that miRNAs represent promising treatments and diagnostic targets in impaired phagocytic clearance, which leads to different diseases.

MicroRNA-126 Level Increases During Exercise Rehabilitation of Heart Failure with a Preserved Ejection Fraction

Objective

To evaluate the changes of plasma levels of miR-126 in heart failure with a preserved ejection fraction (HFpEF) patients undergoing an exercise rehabilitation intervention.

Methods

miR-126 levels in plasma were compared between 60HFpEF patients and 30 healthy volunteers. HFpEF patients underwent exercise rehabilitation for 12 weeks. Before and after rehabilitation, indicators of cardiac function, exercise tolerance, quality of life scores and miR-126 levels were measured and compared. Correlations between plasma levels of miR-126 and HFpEF were evaluated.

Results

The plasma levels of miR-126 in HFpEF patients were lower than those in healthy volunteers and increased significantly after exercise rehabilitation. HFpEF patients also showed significantly better cardiac function, exercise tolerance, and quality of life after rehabilitation. The results of Pearson correlation analysis and multiple linear regression showed that miR-126 levels were positively correlated with peak oxygen consumption (peak VO₂) and metabolic equivalents (METs), and inversely associated with score on the Minnesota Living with Heart Failure Questionnaire (MLHF) as well as plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels.

Conclusion

miR-126 levels are low expressed in plasma among HFpEF patients. Effective exercise rehabilitation in HFpEF patients may positively impact the plasma level of miR-126, which is probably associated with the restoration of cardiac function, exercise tolerance and quality of life. miR-126 may be a potential biomarker for evaluating the efficacy of exercise rehabilitation for HFpEF patients.