Correlation of TTLL7-IT1/Hsa-miR-29c-3p/GLS with limited cutaneous systemic sclerosis and exploration of the underlying mechanisms.

BACKGROUND

Systemic sclerosis (SSc) is an autoimmune disease. In the types of SSc, lcSSc presents with milder symptoms and poses challenges for early diagnosis. Therefore, the identification of biomarkers for earlier diagnosis and the discovery of potential therapeutic targets are of greater significance. This study aims to explore the relationship between competing endogenous RNA (ceRNA) networks, cuproptosis, and lcSSc.

METHODS

RNA sequencing was performed to profile differentially expressed RNAs in blood samples from lcSSc patients and healthy controls. The potential ceRNA network targeting relationships were then examined using a dual-luciferase reporter assay. Subsequently, a series of in vitro experiments utilizing primary CD8+ T cells. These experiments, which included phenotypic assays and molecular analyses, demonstrated the occurrence of cuproptosis. Finally, these findings were validated in vivo in a mouse model through analyses of skin tissues using H&E staining, Masson staining, Immunofluorescence, qPCR, and Western blotting.

RESULTS

TTLL7-IT1/hsa-miR-29c-3p/GLS was constructed using bioinformatic analysis of lcSSc. CD8+ T cells from patients with lcSSc exhibited elevated copper ion levels and reduced glutaminase(GLS) expression, accompanied by alterations in their phenotype and cuproptosis-related proteins. These phenotypic and protein expression changes were reversed by cuproptosis inhibition. Furthermore, cuproptosis exacerbates fibrosis and vascular pathology. Animal experiments further revealed that in bleomycin-induced mouse models, both inhibition of copper ions and GLS overexpression reduced dermal thickness, collagen deposition, fibrotic factor expression, and CD31/α-SMA co-localization in the skin.

CONCLUSIONS

In summary, our findings reveal a functional interaction between cuproptosis and ceRNA networks: TTLL7-IT1/hsa-miR-29c-3p/GLS influences cuproptosis and lcSSc progression, providing new insights into the pathogenesis of lcSSc.