Penehyclidine prevents nuclear factor-kB activation in acute lung injury induced by lipopolysaccharide

Regulation of VDAC1 contributes to the cardioprotective effects of penehyclidine hydrochloride during myocardial ischemia/reperfusion

Penehyclidine hydrochloride (PHC) preconditioning can alleviate myocardial ischemia/reperfusion (I/R) injury and inhibits the upregulation of voltage-dependent anion channel 1 (VDAC1) during I/R. To validate that VDAC1 is a bona fide target of PHC for the protection against myocardial I/R injury, VDAC1 expression construct was delivered by lentiviruses into rat left ventricular myocardium before PHC preconditioning and myocardial I/R. Overexpression of VDAC1 exacerbated cardiac dysfunction and myocardial injury following I/R, and abolished the cardioprotective effect of PHC during I/R injury. Moreover, VDAC1 overexpression with myocardial I/R further increased cytochrome c release from mitochondria to cytoplasm, elevated the levels of cleaved caspase-3 and Bax, and decreased the level of Bcl-2 as compared with I/R alone, and PHC-mediated inhibition of mitochondria-dependent apoptosis during myocardial I/R was abolished by VDAC1 overexpression. In addition, VDAC1 was overexpressed in H9c2 cardiomyocytes undergoing anoxia/reoxygenation (A/R) with or without PHC pretreatment. The in vitro results showed that overexpression of VDAC1 further reduced mitochondrial membrane potential, increased mitochondrial membrane permeability and enhanced mitochondria-dependent apoptosis in H9c2 cells after A/R, and VDAC1 overexpression abrogated the protective effect of PHC on the mitochondrial function and integrity during A/R. In conclusion, exogenous overexpression of VDAC1 during myocardial I/R inhibits the cardioprotective effects of PHC. These effects may be associated with the suppression of VDAC1 expression.

Penehyclidine hydrochloride inhibits TLR4 signaling and inflammation, and attenuates blunt chest trauma and hemorrhagic shock-induced acute lung injury in rats

Blunt chest trauma with hemorrhagic shock (THS) frequently induces pulmonary inflammation that leads to acute lung injury (ALI). Penehyclidine hydrochloride (PHC) possesses anti‑inflammatory properties that may attenuate the systemic inflammatory response. The present study aimed to evaluate the molecular mechanism of PHC in modifying THS‑induced ALI in rats. Rats underwent either THS or a sham procedure. At 6 h subsequent to blunt chest trauma, arterial blood was drawn for blood gas and pro‑inflammatory factors analyses, and lung tissue samples were collected to examine pulmonary histopathological alterations, the wet/dry weight ratio, myeloperoxidase activity, and the protein expression levels of Toll-like receptor 4 (TLR4), phosphorylated (p‑)p38 mitogen‑activated protein kinase (MAPK), nuclear factor (NF)‑κB and activator protein‑1 (AP‑1). THS caused significant reductions in heart rate and mean arterial blood pressure, and was associated with significant increases in tumor necrosis factor‑α, interleukin (IL)‑6, IL‑1β, p‑p38MAPK, NF‑κB and AP‑1 activation, in addition to TLR4 expression, in the lung. PHC effectively attenuated THS‑induced ALI, and inhibited TLR4 expression, reduced the activation of p‑p38MAPK, NF‑κB and AP‑1, and downregulated the expression of pro‑inflammatory mediators. In conclusion, the results of the present study demonstrated that PHC may exert an anti‑inflammatory effect and attenuate THS‑induced ALI by inhibiting the TLR4 signaling pathway. These preclinical findings may offer a novel therapeutic strategy to restrict TLR4 overactivation in ALI.

Role of TLR4 and MAPK in the local effect of LPS on intestinal contractility

OBJECTIVES

Lipopolysaccharide (LPS) has been shown to alter intestinal contractility. Toll-like receptor 4 (TLR4), K(+) channels and mitogen-activated protein kinases (MAPKs) have been proposed to be involved in the mechanism of action of LPS. The aim of this study was to determine the role of TLR4, K(+) channels and MAPKs (p38, JNK and MEK1/2) in the local effect of LPS on the acetylcholine (ACh)-induced contractions in rabbit small intestine in vitro.

METHODS

Segments of rabbit duodenum were suspended in the direction of longitudinal or circular smooth muscle fibres in a thermostatically controlled organ bath.

KEY FINDINGS

LPS (0.3 µg/ml) reduced the contractions induced by ACh (100 µm) in the longitudinal and circular smooth muscle of the duodenum after 90 min of incubation. Polymyxin (TLR4 inhibitor), SB203580 (p38 MAPK inhibitor), SP600125 (JNK1/2 inhibitor) and U0126 (MEK1/2 inhibitor) antagonized the effects of the LPS on ACh-induced contractions in duodenal smooth muscle. Incubation with the blockers of K(+) channels, TEA, apamin, charybdotoxin, iberiotoxin, glibenclamide or quinine, did not reverse the effect of LPS on ACh-induced contractions.

CONCLUSIONS

These results suggest that the effect of LPS on ACh-induced contractions in the rabbit duodenum might be mediated by TLR4 and p38, JNK1/2 and MEK1/2 MAPKs.