Interaction between calcium, neutral endopeptidase and the substance P mediated ciliary response in human respiratory epithelium

Abstract

Following irritation of the airway, the ciliostimulatory effects of the tachykinin, substance P (SP), are thought to be secondary to mucus release. We hypothesized that SP also induces small increases in ciliary beat frequency (CBF) via a calcium-mediated process.Brushed ciliated cells from the nasal epithelium of healthy human subjects were suspended in tissue culture fluid and the acute effects of SP upon these cells were studied in a mucus-free environment. In some preparations, changes in CBF in response to SP were measured with a video-based system. The effect of an SP antagonist, of Ca 2+ channel block with verapamil, and of the calcium analogue lanthanum on the SP response were also tested. In other preparations, the ciliated cells were preloaded with Fura-2, a dye which fluoresces with Ca 2+ ions, and the response of intracellular Ca 2+ to SP was monitored.SP ( We conclude that substance P induces either a transient or sustained increase in CBF dependent on the rate of destruction of this peptide around tachykinin receptors. These receptors are likely to be linked to lanthanum-and verapamil-sensitive pathways for the entry of Ca 2+ into cells. The small magnitude of the rise in CBF makes its physiological role uncertain at present.

Asymmetric interactions between phosphorylation pathways regulating ciliary beat frequency in human nasal respiratory epithelium in vitro.

“…Although the mechanisms which integrate mucus release (Ramnarine, Hirayama, Barnes & Rogers, 1994) with mucus hydration and ciliary activity are incompletely understood, there is overwhelming evidence that protein phosphorylation regulates two key components of mucociliary clearance: the ciliary beat frequency (CBF) and the ion transport which results in fluid absorption/secretion (Sanderson & Dirksen, 1989;Liedtke, 1992;Ismailov & Benos, 1995). Additionally, cell calcium (+ calmodulin) has the potential to integrate all aspects of the mucociliary apparatus: mucus secretion, epithelial fluid elaboration and CBF (Baker, Hilegass, Holden & Smith, 1977;Liedtke, 1992;Salathe, Pratt & Wanner, 1993;Ramnarine et al 1994;Smith, Shellard, Di Benedetto, Magnus & Mehta, 1996). Theoretical models of mucociliary clearance (Satir, Barkalow & Hamasaki, 1993) suggest that the driving force which expels mucus from the lung is dependent on the square of the CBF.…”

Effects of terbutaline in combination with mannitol on mucociliary clearance

“…It is reasonable to assume that a transient increase in [Ca 2z ] i would simply occur as a result of water loss from the epithelial cells following the osmotic stimulus [17], even without an additional release from the intracellular stores or a calcium influx. However, additional increase in [Ca 2z ] i is likely to occur as a result of the mediators [22,23] released in response to mannitol, such as histamine and substance P [18]. Although terbutaline may inhibit the release of mediators from inflammatory cells [28], it is difficult to estimate the magnitude of the possible contribution of mediators in the asthmatics in this study, because there was no difference in the MCC responses between asthmatic and healthy subjects.…”

“…Stimulation of CBF is likely to involve calcium as the cellular events in response to hyperosmolarity of the airway fluid lead to an increase in intracellular calcium ([Ca 2z ] i ) [16,17]. In addition, mediators released in response to hyperosmolarity [18], such as histamine and neuropeptides that stimulate CBF [19,20] and increase MCC [21], have also been reported to cause an increase in [Ca 2z ] i [22,23].…”

Protease-Activated Receptor-2–Mediated Inhibition for Ca2+ Response to Lipopolysaccharide in Guinea Pig Tracheal Epithelial Cells

“…In this study, the PKC-dependent latter mechanism appears to be involved because the LPS-induced increase in [Ca 2ϩ ]i was almost completely or significantly supressed by verapamil, Ca 2ϩ removal ( Figure 5), or chelerythrine, respectively. The presence of voltage-dependent Ca 2ϩ channel in lower airway epithelial cells has not been reported, but it has been suggested in nasal epithelial cells, i.e., substance P-induced increase in ciliary beat frequency depends on Ca 2ϩ influx via this type of Ca 2ϩ channel (24).…”