MicroRNA-29b inhibits human vascular smooth muscle cell proliferation via targeting the TGF-β/Smad3 signaling pathway

Thyroid dysfunction in Hashimoto's thyroiditis: a pilot study on the putative role of miR-29a and TGFβ1

PURPOSE

Hashimoto's thyroiditis (HT) is one of the most common causes of thyroid dysfunction in iodine sufficient worldwide areas, but its molecular mechanisms are not completely understood. To this regard, this study aimed to assess serum levels of miRNA-29a (miR-29a) and transforming growth factor beta 1 (TGFβ1) in HT patients with different patterns of thyroid function.

METHODS

A total of 29 HT patients, with a median age of 52 years (21-68) were included. Of these, 13 had normal thyroid function (Eu-HT); 8 had non-treated hypothyroidism (Hypo-HT); 8 had hypothyroidism on replacement therapy with LT4 (subst-HT). All patients had serum miR-29a assayed through qRT-PCR and serum TGFβ1 assayed by ELISA.

RESULTS

Serum miR-29a levels were significantly down-regulated in patients with Hypo-HT compared to Eu-HT patients (P < 0.01) and subst-HT patients (P < 0.05). A significant negative correlation was detected between serum miR-29a levels and TSH levels (r = -0.60, P < 0.01). Serum TGFβ1 levels were significantly higher in Hypo-HT than both Eu-HT (P < 0.01) and subst-HT patients (P < 0.05). A negative correlation was observed between serum miR-29a and TGFβ1 (r = -0.75, P < 0.01).

CONCLUSIONS

In conclusion, Hypo-HT patients had lower levels of serum miR-29a and higher levels of TGFβ1 in comparison with Eu-HT patients. Worthy of note, subst-HT patients showed restored serum miR-29a levels compared with Hypo-HT group, associated with lower serum TGFβ1. These novel findings may suggest a possible impact of replacement therapy with levothyroxine on serum miR-29a levels in HT.

High glucose promotes atherosclerosis by regulating miRNA let7d-5p level

BACKGROUND

MiRNA let7d-5p has been recently reported to be abnormally expressed in diabetes-associated atherosclerosis (AS). However, it still remains unknown how let7d-5p contributes to the process of atherosclerosis.

METHODS

Twenty fresh tissues and a total of 28 wax block specimens from carotid endarterectomy procedures were obtained from the Luoyang Central Hospital affiliated to Zhengzhou University. The expression of let7d-5p was assessed using quantitative RT-PCR (qRT-PCR). A series of in vitro experiments was used to determine the roles of let7d-5p knockdown and overexpression in vascular smooth muscle cells (VSMCs).

RESULTS

We discovered that the carotid plaques from diabetic patients had lower expression levels of miR let7d-5p. In VSMCs, the expression of miRNA let7d-5p was significantly lower in high glucose conditions compared with low glucose situations. The proliferation and migration of VSMCs were also inhibited by the overexpression of let7d-5p, whereas the opposite was true when let7d-5p was inhibited, according to gain and loss of function studies. Mechanically, let7d-5p might activate the GSK3β/β-catenin signaling pathway via binding to the high mobility group AT-Hook 2 (HMGA2) mRNA in VSMCs. Additionally, GLP-1RA liraglutide may prevent the migration and proliferation of VSMCs by raising let7d-5p levels.

CONCLUSIONS

High glucose stimulated the proliferation and migration of VSMCs by regulating the let7d-5p/HMGA2/GSK3β/β-catenin pathway, and liraglutide may slow atherosclerosis by increasing the levels of miR let7d-5p.

Vascular smooth muscle cells in intracranial aneurysms

Intracranial aneurysm (IA) is a severe cerebrovascular disease characterized by abnormal bulging of cerebral vessels that may rupture and cause a stroke. The expansion of the aneurysm accompanies by the remodeling of vascular matrix. It is well-known that vascular remodeling is a process of synthesis and degradation of extracellular matrix (ECM), which is highly dependent on the phenotype of vascular smooth muscle cells (VSMCs). The phenotypic switching of VSMC is considered to be bidirectional, including the physiological contractile phenotype and alternative synthetic phenotype in response to injury. There is increasing evidence indicating that VSMCs have the ability to switch to various phenotypes, including pro-inflammatory, macrophagic, osteogenic, foamy and mesenchymal phenotypes. Although the mechanisms of VSMC phenotype switching are still being explored, it is becoming clear that phenotype switching of VSMCs plays an essential role in IA formation, progression, and rupture. This review summarized the various phenotypes and functions of VSMCs associated with IA pathology. The possible influencing factors and potential molecular mechanisms of the VSMC phenotype switching were further discussed. Understanding how phenotype switching of VSMC contributed to the pathogenesis of unruptured IAs can bring new preventative and therapeutic strategies for IA.

The Microenvironment That Regulates Vascular Wall Stem/Progenitor Cells in Vascular Injury and Repair

Vascular repair upon injury is a frequently encountered pathology in cardiovascular diseases, which is crucial for the maintenance of arterial homeostasis and function. Stem/progenitor cells located on vascular walls have multidirectional differentiation potential and regenerative ability. It has been demonstrated that stem/progenitor cells play an essential role in the basic medical research and disease treatment. The dynamic microenvironment around the vascular wall stem/progenitor cells (VW-S/PCs) possesses many stem cell niche-like characteristics to support and regulate cells' activities, maintaining the properties of stem cells. Under physiological conditions, vascular homeostasis is a cautiously balanced and efficient interaction between stem cells and the microenvironment. These interactions contribute to the vascular repair and remodeling upon vessel injury. However, the signaling mechanisms involved in the regulation of microenvironment on stem cells remain to be further elucidated. Understanding the functional characteristics and potential mechanisms of VW-S/PCs is of great significance for both basic and translational research. This review underscores the microenvironment-derived signals that regulate VW-S/PCs and aims at providing new targets for the treatment of related cardiovascular diseases.

MicroRNAs as monitoring markers for right-sided heart failure and congestive hepatopathy

The last decades showed a worrying increase in the evolution of cardiovascular diseases towards different stages of heart failure (HF), as a stigma of the western lifestyle. MicroRNAs (miRNAs), non-coding RNAs, which are approximately 22-nucleotide long, were shown to regulate gene expression at the post-transcriptional level and play a role in the pathogenesis and progression of HF. miRNAs research is of high interest nowadays, as these molecules display mechanisms of action that can influence the course of evolution of common chronic diseases, including HF. The potential of post-transcriptional regulation by miRNAs concerning the diagnosis, management, and therapy for HF represents a new promising approach in the accurate assessment of cardiovascular diseases. This review aims to assess the current knowledge of miRNAs in cardiovascular diseases, especially right-sided heart failure and hepatomegaly. Moreover, attention is focused on their role as potential molecular biomarkers and more promising aspects involving miRNAs as future therapeutic targets in the pathophysiology of HF.