MicroRNA-219-5p inhibits wound healing by targeting TMEM98 in keratinocytes under normoxia and hypoxia condition

Landscape of the epigenetic regulation in wound healing

Wound healing after skin injury is a dynamic and highly coordinated process involving a well-orchestrated series of phases, including hemostasis, inflammation, proliferation, and tissue remodeling. Epigenetic regulation refers to genome-wide molecular events, including DNA methylation, histone modification, and non-coding RNA regulation, represented by microRNA (miRNA), long noncoding RNA (lncRNA), and circular RNA (circRNA). Epigenetic regulation is pervasively occurred in the genome and emerges as a new role in gene expression at the post-transcriptional level. Currently, it is well-recognized that epigenetic factors are determinants in regulating gene expression patterns, and may provide evolutionary mechanisms that influence the wound microenvironments and the entire healing course. Therefore, this review aims to comprehensively summarize the emerging roles and mechanisms of epigenetic remodeling in wound healing. Moreover, we also pose the challenges and future perspectives related to epigenetic modifications in wound healing, which would bring novel insights to accelerated wound healing.

Shuxie-1 Decoction Alleviated CUMS -Induced Liver Injury via IL-6/JAK2/STAT3 Signaling

Introduction: Chronic stress has been shown to cause liver damage in addition to psychological depression. Besides, drug-induced liver injury is frequently caused by antidepressants. Shuxie-1 decoction (SX-1) is a formula of traditional Chinese medicine commonly used in nourishing liver blood, and relieving depression. However, the underlying molecular mechanism remains unclear. Therefore, this study was designed to explore the effects and mechanisms of SX-1 in treating chronic stress-induced depression as well as liver injury.

Methods: Chronic unpredictable mild stress (CUMS) was applied to male Wistar rats for 4 weeks, with or without administration of SX-1 at low-dose and high-dose for 6 weeks, using Fluoxetine (Flu) as a positive control. Body weight was monitored once every 2 weeks. In the sixth week, the sugar preference test and open field test were carried out to evaluate the depression status. After that, the serum and liver tissues were collected. The quality control of SX-1 decoctions and drug-containing serum was controlled by UHPLC-QE-MS. The cell viability was measured by Cell Counting Kit-8 (CCK8). Enzyme-linked immunosorbent assay (Elisa), Western Blot and immunohistochemistrical staining was obtained to detect the protein levels in the plasma and the hepatic tissues, respectively.

Results: CUMS led to decreased 1) body weight, 2) the preference for sugar water, 3) the desire to explore in open field, and increased serum levels of corticosterone. All these factors were completely reversed by SX-1 treatment. Hematoxylin-eosin staining (HE) showed that SX-1 improved the hepatocyte vacuolization in CUMS treated rats, decreased the serum levels of alanine aminotransferase (ALT) and the deposition of type I collagen (Col I) in hepatocytes as well. CUMS increased the levels of hepatic Interleukin-6 (IL-6), and provoked the activation of Janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3), which was abrogated by SX-1 treatment. Cobalt chloride (CoCl₂) increased the protein expression of IL-6 and p-STAT3 in AML12 cells. Besides, nuclear pyknosis was observed under electron microscope, which were recovered after rat SX serum.

Conclusion: SX-1 effectively ameliorated CUMS-induced depression-like behaviors as well as hepatic injuries, probably by the blockade of hepatic IL-6/JAK2/STAT3 signaling.

MicroRNA-219-5p participates in cyanotic congenital heart disease progression by regulating cardiomyocyte apoptosis

MicroRNAs (miRs) play important roles in the protection against and development of congenital heart disease (CHD). However, the role and potential mechanisms of miR-219-5p in cyanotic CHD remains unclear. Reverse transcription-quantitative PCR (RT-qPCR) was used to measure miR-219-5p levels in cyanotic CHD and hypoxia-induced H9C2 cells. Dual luciferase reporter gene assay was used to confirm whether liver receptor homolog-1 (LRH-1) was a direct target of miR-219-5p. miR-219-5p inhibitor and LRH-1-small interfering RNA were transfected into H9C2 cells under hypoxic conditions to investigate the role of miR-219-5p in hypoxia-induced H9C2 cells. Subsequently, cell viability was detected using an MTT assay and cell apoptosis was detected using flow cytometry. In addition, RT-qPCR and western blotting assays were performed to detect the mRNA and protein expression of LRH-1, cyclin D1 and β-catenin, respectively. The data showed that miR-219-5p expression was higher in patients with cyanotic CHD compared with patients with acyanotic CHD gradually increased in H9C2 cells with prolonged hypoxia time. Dual luciferase reporter assay results showed that LRH-1 was a direct target gene of miR-219-5p. Inhibition of miR-219-5p reversed hypoxia-induced cell viability reduction and attenuated hypoxia-induced cell apoptosis. In addition, hypoxia induction inhibited the expression of LRH-1, cyclin D1 and β-catenin, which was reversed by miR-219-5p inhibitor. However, LRH-1 downregulation reversed the miR-219-5p inhibitor enhanced cell viability, decreased cell apoptosis and increased expression of LRH-1, cyclin D1 and β-catenin in hypoxia-treated cardiomyocytes. The present results demonstrated that downregulation of miR-219-5p promoted the expression of the LRH-1/Wnt/β-catenin signaling pathway-associated components, reduced cardiomyocyte apoptosis and increased cell growth under hypoxic conditions. miR-219-5p may be a potential therapeutic target for cyanotic CHD therapy.

The nanophthalmos protein TMEM98 inhibits MYRF self-cleavage and is required for eye size specification

The precise control of eye size is essential for normal vision. TMEM98 is a highly conserved and widely expressed gene which appears to be involved in eye size regulation. Mutations in human TMEM98 are found in patients with nanophthalmos (very small eyes) and variants near the gene are associated in population studies with myopia and increased eye size. As complete loss of function mutations in mouse Tmem98 result in perinatal lethality, we produced mice deficient for Tmem98 in the retinal pigment epithelium (RPE), where Tmem98 is highly expressed. These mice have greatly enlarged eyes that are very fragile with very thin retinas, compressed choroid and thin sclera. To gain insight into the mechanism of action we used a proximity labelling approach to discover interacting proteins and identified MYRF as an interacting partner. Mutations of MYRF are also associated with nanophthalmos. The protein is an endoplasmic reticulum-tethered transcription factor which undergoes autoproteolytic cleavage to liberate the N-terminal part which then translocates to the nucleus where it acts as a transcription factor. We find that TMEM98 inhibits the self-cleavage of MYRF, in a novel regulatory mechanism. In RPE lacking TMEM98, MYRF is ectopically activated and abnormally localised to the nuclei. Our findings highlight the importance of the interplay between TMEM98 and MYRF in determining the size of the eye.