MiR‐21‐3p modulates lipopolysaccharide‐induced inflammation and apoptosis via targeting TGS4 in retinal pigment epithelial cells

Abstract

Age-related macular degeneration (AMD) is the most common cause of blindness and visual impairment in the elderly. 1 AMD is characterized by accumulation of yellow crystal deposits and loss of central vision due to degenerative changes in the macula. The integrity of the retina is strongly related to retinal pigment epithelial cells, which maintain the local extracellular environment. Morphological and functional abnormalities of these cells can lead to AMD. 2 Inflammation and apoptosis also play central roles in the pathophysiology of AMD. 3,4 Determining appropriate treatment for AMD is an important endeavour to increase patient quality of life.MicroRNAs (miRs) are a class of noncoding RNAs that can inhibit or degrade genetic targets by binding to their 3ʹ untranslated regions (UTRs). MiRs play integral roles in numerous disease processes, including oxidase stress, inflammation, and apoptosis. 5 For AbstractAge-related macular degeneration (AMD) is a major reason of blindness in the elderly.MicroRNAs are implicated in various pathological processes, including inflammation and apoptosis. In this study, we aim to investigate the biological functions of miR- 21-3p in inflammation and apoptosis caused by lipopolysaccharide (LPS) in humanretinal pigment epithelial (ARPE-19) cells. The miR-21-3p inhibitor and mimic were transfected into ARPE-19 cells for 48 hours, followed by exposed to LPS (10 μg/mL) for 24 hours. The mRNA and protein expression of IL-6 and MCP-1 were measured using real-time PCR (RT-PCR) and enzyme-linked immunosorbent assays. Cell viability, apoptosis, caspase 3 activity, cleaved caspase-3 and cleaved-PARP protein levels were detected to evaluate the effects of miR-21-3p on apoptosis. Additionally, the target relationship between miR-21-3p and regulator of G-protein signalling 4 (RGS4) was verified by dual luciferase reporter assay. RT-PCR analysis demonstrated that LPS induced miR-21-3p expression. Inhibition of miR-21-3p reduced the mRNA and protein levels of IL-6 and MCP-1. Apoptosis, caspase-3 activity, and cleaved-caspase 3 and cleaved PARP protein levels were repressed by the miR-21-3p inhibitor.However, overexpression of miR-21-3p showed the opposite results. Furthermore, we identified that miR-21-3p directly targeted the 3ʹ untranslated region of RGS4.MiR-21-3p negatively regulated the expression of RGS4 both in mRNA and protein levels. Silencing RGS4 reduced the anti-inflammatory and anti-apoptotic effects of miR-21-3p inhibitor. Our results revealed that miR-21-3p inhibition targeted RGS4 to attenuate inflammatory responses and apoptosis caused by LPS in ARPE-19 cells. K E Y W O R D Sapoptosis, inflammation, MiR-21-3p, RGS4

The potential role of miR-21-3p in coronavirus-host interplay

“…Consecutive increase in the HDAC8 expression was shown to promote viral replication. (Liu et al, 2019). The apoptosis inhibition was shown to happen due to the targeting of the 3'-UTR of RGS4 mRNA by miR-21-3p.…”

Mir-21 Suppression Promotes Mouse Hepatocarcinogenesis

“…Interestingly, miR-21* (or miR-21-3p) is now reported as a functionally relevant passenger strand, as shown in human HepG2 hepatoblastoma cells where it inhibited growth and triggered apoptosis [ 77 ], but promoted, in another study, migration and invasion of the same cells [ 63 ]. MiR-21* was also reported to play a significant role in other processes such as cardiac and renal fibrosis [ 78 , 79 ], hypertension [ 80 ], or inflammation [ 81 , 82 , 83 ]. We cannot exclude that the in vivo genetic deletion of miR-21* in hepatocytes also contributes to the exacerbated hepatocarcinogenesis seen in miR21KO, LmiR21KO, and LPTENmiR21KO mice.…”

Differential mRNA and miRNA Profiles Reveal the Potential Roles of Genes and miRNAs Involved in LPS Infection in Chicken Macrophages

“…In a human umbilical vein endothelial cell angiogenesis study, the knockdown of miR-146a activated transforming growth factor-β1 signaling to inhibit angiogenesis [ 39 ]. Recently, the miR-21-3p was verified to target RGS4 and attenuate inflammatory responses and apoptosis caused by LPS in ARPE-19 cells [ 40 ].…”