Downregulation of hsa_circ_0002198 inhibits keloid fibroblast activities in vitro by reducing NLRP3 inflammasome activity

Lei Fu,Fengting Zhu,Hui Zhang,Xuewu Chen,Jingwen Jiang

doi:10.32604/biocell.2022.016726

Abstract

The levels of hsa circular RNA_0002198 (hsa_circ_0002198) have been found to be significantly upregulated in keloid dermal fibroblasts. However, the functional role of hsa_circ_0002198 in keloid fibroblasts and the underlying molecular mechanism for its effects have not been reported. In this study, the levels of hsa_circ_0002198 and nucleotide-binding and oligomerization domain, leucine rich repeat and pyrin domain containing 3 (NLRP3) expression in keloid scar tissues and adjacent normal skin tissues were determined by quantitative real-time PCR and western blotting, respectively. In vitro models of keloid tissue were created by culturing primary keloid fibroblasts obtained from patients. A series of functional experiments, including CCK-8 assays, Transwell assays, and ELISA assays were performed to analyze the functional role of hsa_circ_0002198/NLRP3. Our data showed that hsa_circ_0002198 and NLRP3 were upregulated in keloid scar tissues when compared with adjacent normal tissues. Knockdown of hsa_circ_0002198 expression significantly suppressed cell proliferation, migration, and invasion, and those effects could be partially reversed by forced NLRP3 overexpression in keloid fibroblasts. At the molecular level, knockdown of hsa_circ_0002198 downregulated the levels of Col I, α-SMA, and NLRP3 proteins, as well as the levels of TGF-β, IL-1ß, and IL-33, but upregulated caspase 3 expression in keloid fibroblasts. All those effects were partially reversed after NLRP3 overexpression. In conclusion, our results suggest hsa_circ_0002198 as a potential target for treating keloid lesions.

Highlights

A keloid scar is regarded as a chronic inflammatory process characterized by an accumulation of fibroblasts and excessive deposition of extracellular matrix (ECM) components, and especially collagen that is deposited due to an abnormal wound healing process (Abergel et al, 1985; Sidgwick and Bayat, 2012; Vincent et al, 2008)
We observed that hsa_circ_0002198 expression was upregulated in keloid scar tissues when compared with adjacent normal tissues. This finding was in agreement with data reported by Zhang et al (2020), who performed an RNA-Seq data analysis showing that hsa_circ_0002198 expression was significantly elevated in human keloid dermal fibroblasts when compared with normal dermal fibroblasts
Results from loss-of-function assays indicated that knockdown of hsa_circ_0002198 significantly suppressed the proliferation, migration, and invasion of keloid fibroblasts

Summary

Introduction

A keloid scar is regarded as a chronic inflammatory process characterized by an accumulation of fibroblasts and excessive deposition of extracellular matrix (ECM) components, and especially collagen that is deposited due to an abnormal wound healing process (Abergel et al, 1985; Sidgwick and Bayat, 2012; Vincent et al, 2008). Several gene regulators, including cytokines and chemokines, have been previously reported to be involved in. CircRNAs are produced by precursor mRNA back-splicing, are widely expressed in mammals, and involved in various diseases (Han et al, 2017; Szabo and Salzman, 2016; Wang et al, 2016; Xu et al, 2015). Wang et al (2019a) and Shi et al (2020) performed bioinformatics analyses which identified differentially expressed circRNAs associated with keloid formation. In agreement with a data analysis performed by Zhang et al (2020), hsa_circ_0002198 has been identified by bioinformatics tools and verified to be significantly upregulated in keloid dermal fibroblasts. The mechanism by which hsa_circ_0002198 regulates the formation of keloid scars, and the association between hsa_circ_0002198 and NLRP3, have not been reported

Methods

Results

Conclusion