rhPTH(1-34) regulates PTHCHD1 to restore contact inhibition and modulate keratinocyte proliferation

Summary: Abstract Body: The study aimed to investigate whether recombinant rhPTH(1-34) can restore contact inhibition by regulating PTCHD1 and thereby modulating the proliferation of keratinocytes (HaCaT). HaCaT cells were treated with rhPTH(1-34). Western blotting was employed to assess the expression levels of PTCHD1 and the downstream target genes of the Hh signaling pathway, including CCND1, CCND2, CDK1, and CCNB1. Cell adhesion assays were conducted to calculate adhesion indices; DAPI staining was performed to observe nuclear morphology; crystal violet staining assessed cell adhesion under microscopy; and BrdU immunofluorescence was utilized to evaluate cell proliferation capacity. Additionally, PTCHD1 overexpression was induced in HaCaT cells via lentiviral infection, followed by rhPTH(1-34) treatment for 48 hours. Cell viability was evaluated using the CCK8 method, while flow cytometry was employed to analyze the cell cycle. RT-PCR and Western blotting were also performed to detect PTCHD1, CCND1, CCNB1, CCND2, and CDK1 expression. The effects of the treatment on the states of cell adhesion, DAPI staining, crystal violet staining, and BrdU immunofluorescence were observed to assess contact inhibition status following PTCHD1 overexpression. rhPTH(1-34) inhibited the proliferation of HaCaT cells and induced cell cycle arrest in the G1 phase, thereby restoring intercellular contact inhibition. This compound suppressed the proliferation of HaCaT cells by downregulating PTCHD1. Notably, the proliferation capacity and contact inhibition status of PTCHD1-overexpressing cells were reversed upon treatment, with a significant increase in the number of cells arrested in the G1 phase. rhPTH(1-34) inhibits keratinocyte proliferation by regulating the cell cycle and upregulating PTCHD1, ultimately restoring cell contact inhibition. Jing Guo³, Xiaolin Bu¹, Liwei Feng², Rongzhu Yu² 1. Dermatology, Shanghai Pudong New Area Gongli Hospital, Shanghai, Shanghai, China. 2. School of Gongli Hospital Medical Technology, University of Shanghai for Science and Technology, Shanghai, Shanghai, China. 3. Postgraduate training base at Shanghai Gongli Hospital, Ningxia Medical University, Yinchuan, Ningxia, China. Genetic Disease, Gene Regulation, Gene Therapy & Epigenetics