Rnaset2 inhibits melanocyte outgrowth possibly through interacting with shootin1.

BACKGROUND: Impaired dendrite outgrowth of melanocytes is one of the reasons triggering vitiligo. RNASET2 was identified as one of the risk genes for vitiligo in a GWAS study conducted in the Chinese Han population. However, the role of Rnaset2 in the outgrowth of melanocytes is rarely studied.

OBJECTIVE: This study is to investigate the effects of Rnaset2 in regulating the outgrowth of melanocytes and its interacting proteins.

METHODS: Stress conditions (UV irradiation, hydrogen peroxide, and lipopolysaccharides) were applied to primary human epidermal melanocytes (HEMs) and epidermal keratinocytes (HEKs). HEKs with Rnaset2 overexpression were co-cultured with HEMs. Rnaset2 expression levels were detected by ELISA. HEMs, HEKs and A375 cells were treated with recombinant Rnaset2 protein and actin network was observed with fluorescence microscope. Cell migration assay was performed using nuclepore filters after incubating A375 cells with recombinant Rnaset2 protein. Human proteome microarray was performed to identify proteins interacting with Rnaset2. Co-immunoprecipitation was conducted to verify the results.

RESULTS: Our results showed that after exposing to stress conditions, Rnaset2 expression and secretion by HEKs and HEMs were increased. Co-culture of HEKs and HEMs showed that outgrowth of HEMs was inhibited by Rnaset2 overexpression in HEKs. Additionally, human recombinant Rnaset2 protein treatment altered the actin network of HEMs, HEKs and A375 cells. The migration of A375 cells was also inhibited by human recombinant Rnaset2 protein treatment. Human proteome microarray identified shootin1, an important protein involved in axon outgrowth, as one of the interacting proteins of Rnaset2. Co-immunoprecipitation confirmed that Rnaset2 interacted with shootin1 in vitro.

CONCLUSION: Rnaset2 inhibits melanocyte outgrowth through interacting with shootin1 and this effect may be associated with vitiligo pathogenesis. Rnaset2 may be a potential therapeutic target for vitiligo.