Inflammatory cytokines tumour necrosis factor‐α and interleukin‐8 enhance airway smooth muscle contraction by increasing L‐type Ca²⁺ channel expression

Abstract

Inflammation elevates intracellular calcium concentrations ([Ca ] ) in airway smooth muscle (ASM). The L-type Ca channel (L-VDCC) plays an important role in regulating Ca influx in ASM. However, the role of L-VDCC in the inflammatory cytokine-induced pathology of ASM remains unclear. In the present study, we used calcium imaging and isometric tension measurements to assess the role of L-VDCC in agonist-induced [Ca ] rise and the associated contractions in mouse ASM, and we used immunoblotting to identify L-VDCC protein expression levels in mouse ASM after exposure to tumour necrosis factor alpha (TNF-α) or interleukin-8 (IL-8). Our results showed that high-K - or carbachol-induced contractions of mouse ASM were significantly greater after pretreatment with TNF-α or IL-8 for 24 hours. Both verapamil and nifedipine, L-VDCC inhibitors, abolished this increased contraction induced by TNF-α or IL-8 pretreatment. Moreover, TNF-α treatment enhanced carbachol-induced Ca influx in ASM cells, and this effect was abrogated by verapamil. Additionally, immunoblotting results showed that preincubation of mouse ASM with TNF-α or IL-8 also enhanced L-VDCC protein expression. On the basis of these findings, we concluded that proinflammatory cytokines, such as TNF-α and IL-8, increase the expression level of L-VDCC, which in turn contributes to augmented agonist-induced ASM contractions. This effect of inflammation on L-VDCC expression in ASM may be associated with airway hyper-responsiveness and involved in the development of asthma.

Anti-Contractile and Anti-Inflammatory Effects of Diacerein on Isolated Mouse Airways Smooth Muscle and Mouse Asthma Model

“…The RT-PCR results showed that the increased expression levels of TNF, Muc5ac, IL-4, IL-13, and IL-12b in asthmatic mice was significantly reduced in diacerein-treated mice, which elucidated that diacerein might provide anti-inflammatory benefit via reducing these inflammatory mediators. Besides that, previous study also demonstrated that inflammatory cytokines might enhance ASM contraction by increasing expressions of certain ion channels and elevating intracellular calcium concentrations (Ding et al, 2019), which implied that the anti-contractile feature of diacerein might also benefit from down-regulated inflammatory mediators. However, more experiments need to be conducted to confirm it.…”

3D-printed drug testing platform based on a 3D model of aged human skeletal muscle

“…Moreover, this behavior differs from that observed in 3D-bioengineered C2C12 cells, which only show a sustained tetanic contraction for frequencies higher than 10 Hz without an initial stroke 2 . TNF-α is a proinflammatory cytokine known to be related to sarcopenia, or loss of muscle mass and function in ageing, as well as reduction of cell fusion [25][26][27][28][29][30][31] . Hence, we examined whether addition of this cytokine could be used to model aged skeletal muscle tissue in our muscle platform.…”

“…This cytokine has been described as one of the main drivers for the known morphological changes that take place in senescent muscles [23][24][25] , and has been linked to the development of sarcopenia affecting satellite cells 26 . In mouse cell lines, differences in TNF-α have been related to changes in calcium transients 27,28 and reduction of contractile force 25 . Furthermore, in vitro, this cytokine is known to have an effect on myogenesis inhibition 29 and cause atrophy 30 , as demonstrated in C2C12 cell lines, as well as having an important effect in muscle regeneration after injury in vivo 31 .…”

PDE3-inhibitor enoximone prevented mechanical ventilation in patients with SARS-CoV-2 pneumonia

“…histamine, bradykinin, and LTs), which have been reported to contribute to SARS-CoV-2induced inflammation. 4 A major consideration is that several of the pro-inflammatory mediators released by effector cells in COVID-19 act on airway smooth muscle cells and induce bronchoconstriction, 4,27,28 which can be relieved by (combined) PDE3-inhibitors producing (potent and sustained) bronchodilation. 5,[7][8][9][10]21 Recently, based on their broad anti-inflammatory activity, systemic corticosteroids have been advocated in severe COVID-19 patients requiring supplemental oxygen (i.e., with a similar indication as our COVID-19 cases) in line with the preliminary findings in the RECOVERY study.…”