M 3 receptor is involved in the effect of penehyclidine hydrochloride reduced endothelial injury in LPS-stimulated human pulmonary microvascular endothelial cell

LPS has been recently shown to induce muscarinic acetylcholine 3 receptor (M3 receptor) expression and penehyclidine hydrochloride (PHC) is an anticholinergic drug which could block the expression of M3 receptor. PHC has been demonstrated to perform protective effect on cell injury. This study is to investigate whether the effect of PHC on microvascular endothelial injury is related to its inhibition of M3 receptor or not. HPMVECs were treated with specific M3 receptor shRNA or PBS, and randomly divided into LPS group (A group), LPS+PHC group (B group), LPS + M3 shRNA group (C group) and LPS + PHC + M3 shRNA group (D group). Cells were collected at 60 min after LPS treatment to measure levels of LDH, endothelial permeability, TNF-α and IL-6 levels, NF-κB p65 activation, I-κB protein expression, p38MAPK, and ERK1/2 activations as well as M3 mRNA expression. PHC could decrease LDH levels, cell permeability, TNF-α and IL-6 levels, p38 MAPK, ERK1/2, NF-κB p65 activations and M3 mRNA expressions compared with LPS group. When M3 receptor was silence, the changes of these indices were much more obvious. These findings suggest that M3 receptor plays an important role in LPS-induced pulmonary microvascular endothelial injury, which is regulated through NF-κB p65 and MAPK activation. And knockout of M3 receptor could attenuate LPS-induced pulmonary microvascular endothelial injury. Regulative effects of PHC on pulmonary microvascular permeability and NF-κB p65 as well as MAPK activations are including but not limited to inhibition of M3 receptor.