Objective:To evaluate the expression level of hsa-miR-422a in hypertrophic scars and to identify the target genes of hsa-miR-422a along with their biological functions using bioinformatics approaches.Methods:From June 2020 to December 2020, tissue samples of 3 hypertrophic scar and 3 normal skin were collected from patients (3 males, 3 females, aged 20-42 years) in Department of Plastic and Reconstructive Surgery, Shanghai Ninth People′s Hospital, Shanghai Jiaotong University School of Medicine. Primary fibroblasts were isolated and cultured. Real-time quantitative PCR was performed to quantify the expression of hsa-miR-422a. To construct a ceRNA network, starbase and Target Scandata bases were utilized to predict genes as well as long noncoding RNAs (lncRNAs) that may sponge hsa-miR-422a. GO and KEGG pathway enrichment analyses were conducted on the target genes of hsa-miR-422a; protein-protein interaction (PPI) networks were constructed to identify the hub genes whose functions were predicted by functional enrichment analyses. The expression of hub genes was validated through real-time quantitative PCR in hypertrophic scars.Results:The expression of hsa-miR-422a was significantly lower in the hypertrophic scar tissue samples and fibroblasts compared to that in the normal skin ( P<0.05). 133 target genes as well as 1033 lncRNAs were predicted by starBase and TargetScandata bases and used to construct an hsa-miR-422a-centered ceRNA network. PPI networks of the target genes revealed 10 hub genes, including MAPK1, GRB2, and IGF1R, which were discovered to be related to protein serine/threonine/tyrosine kinase activity, ubiquitin protein ligase binding, fibroblast growth factor receptor signaling pathway, muscle cell proliferation, and many others; besides, they may be involved in FoxO, mTOR, Toll-like receptor, Ras, MAPK, PI3K-Akt signaling pathways and signaling pathways regulating pluripotency of stem cells. Three hub genes (MAPK1, GRB2, and IGF1R) were significantly upregulated in hypertrophic scars ( P<0.05). Conclusions:hsa-miR-422a is significantly downregulated in the hypertrophic scars and may target hub genes such as MAPK1 in ceRNA networks, ultimately modulating hypertrophic scar formation.

Spinal muscular atrophy, lower extremity-predominant, 2A (SMALED2A) is a form of spinal muscular atrophy, which predominantly affects muscles of the lower extremity, characterized by early childhood onset of muscle weakness and atrophy. This disorder is caused by mutation in the BICD2 gene. This paper reports a case of SMALED2A with recurrent skin ulceration of both feet. Whole exome sequencing of this case revealed a chr9∶95527083_A>AGCC insertion mutation in the 5’UTR of BICD2 gene.

Spinal muscular atrophy, lower extremity-predominant, 2A (SMALED2A) is a form of spinal muscular atrophy, which predominantly affects muscles of the lower extremity, characterized by early childhood onset of muscle weakness and atrophy. This disorder is caused by mutation in the BICD2 gene. This paper reports a case of SMALED2A with recurrent skin ulceration of both feet. Whole exome sequencing of this case revealed a chr9∶95527083_A>AGCC insertion mutation in the 5’UTR of BICD2 gene.