PKG1 promotes the HIV-induced proliferation, migration, and fibrosis of vascular smooth muscle cells of hemorrhoids.

Background: Hemorrhoids are very common in patients with human immunodeficiency virus (HIV) infection. The risk of postoperative infection is significantly greater in HIV-positive patients than in HIV-negative individuals, and the wound healing time is significantly prolonged. This study aimed to investigate the role of HIV-associated hemorrhoids from the perspective of vascular smooth muscle cell (VSMC) function.

Methods: A total of 24 hemorrhoid tissue samples (note: grade IV hemorrhoids were absence) were collected and subjected to Masson staining to evaluate fibrosis in this study. mRNA and protein levels were monitored by qPCR and WB analysis, respectively. Immunofluorescence was conducted to evaluate PKG1 and α-SMA expression. To establish a cell model in vitro, VSMCs were stimulated with envelope glycoprotein (gp) 120, which is a type of HIV envelope protein. Cell proliferation was assessed via a CCK-8 assay and EdU staining. Moreover, a wound healing assay was performed to assess cell migration.

Results: Our data confirmed that fibrosis was present in hemorrhoid tissues from HIV-infected patients and that PKG1 expression was upregulated. Moreover, the administration of HIV gp120 promoted the proliferation and migration of VSMCs. Similarly, fibrosis-related markers (α-SMA, MMP2, MMP3, and TIMP1) were markedly upregulated. However, silencing PKG1 inhibited the proliferation, migration, and expression of fibrosis-related markers in gp120-challenged VSMCs.

Conclusion: The present research revealed that PKG1 regulated the proliferation, migration, and fibrosis of VSMCs, thereby exerting detrimental effects on HIV-associated hemorrhoids.