The role of LNK in mitigating hypertension: inhibition of vascular smooth muscle proliferation and JAK-STAT pathway.

Abstract

The lymphocyte adaptor protein LNK is predominantly found in endothelial and hematopoietic cells and is linked to cardiovascular and autoimmune diseases. LNK functions as a negative regulator of cytokine signaling and cell proliferation, but its impact on hypertensive vascular smooth muscle cells (HVSMC) remains unclear. This study aimed to explore the influence of LNK on HVSMC function. To achieve this, vascular smooth muscle cells (VSMCs) from rat thoracic aorta were isolated and identified using immunofluorescence. A hypertensive cell model was established by treatment with angiotensin-II, confirmed through the MTT method. Lentivirus was utilized to create stable silencing and overexpression of the LNK gene. Flow cytometry assessed VSMC cycle, proliferation, and migration levels, while ELISA measured IL-6, TNF-α, and IFN-γ expression levels. Real-time quantitative PCR and western blot were employed to analyze LNK, STAT3, JAK1, JAK2, JAK3 mRNA, and protein expression in rat VSMC. Immunofluorescence results indicated that most VSMCs expressed vimentin, with a proliferation rate of 48.5% in VSMCs treated with 100 nM angiotensin-II, confirming successful isolation and model construction of HVSMC. Compared to the control group, the angiotensin-II group exhibited increased HVSMCs in S and G2/M-phases of the cell cycle, decreased in G0/G1 phases, higher proliferation and migration capacity, and elevated inflammation levels. Additionally, JAK1, JAK2, and STAT3 signaling pathway-related mRNA and protein expression were significantly elevated. These effects were further intensified by the combined action of angiotensin-II and LNK silencing virus. Conversely, these effects were notably reduced when angiotensin-II was combined with the LNK overexpressing virus. These findings suggest that LNK mitigates the impact of hypertension and inflammation by inhibiting the proliferation, migration, and JAK-STAT signaling pathway of HVSMCs.