Calcium regulation of ciliary beat frequency in human respiratory epithelium in vitro.

Abstract

SUMMARY1. The changes in ciliary beat frequency (CBF) of human nasal respiratory epithelial cells were measured in vitro with a photometric technique following exposure to either 4-bromo-calcium ionophore A23187 (4-Br-A23187) or trifluoperazine (TFP), an inhibitor of calmodulin-sensitive calcium-dependent protein kinases. Changes in intracellular free calcium concentrations in response to 4-Br-A23187 were studied using a fluorescent dye (Fura-2).2. Addition of 10' M-4-Br-A23187 caused a time-dependent (P < 001) rise in CBF. The increment in CBF was statistically significant 10 min after challenge (+ 10 %; P < 0 01) and was sustained for at least 1 h, with maximal stimulation after 40 min (+ 18 %; P < 0-01).3. Exposure to 10' M-4-Br-A23187 caused an immediate increase in intracellular free calcium concentration, which preceded the rise in CBF.4. TFP (10' M) caused a reduction of baseline CBF (-10%; P < 001) and prevented the expected rise when the cells were subsequently exposed to 10' M-4-Br-A23187.5. We conclude that: (1) calcium ionophore stimulates the CBF of human respiratory cells; (2) this effect is mediated through a calmodulin-sensitive system, since it is abolished in the presence of TFP; (3) the same pathway appears to control the basal CBF of these cells, since TFP also decreases CBF.

Effect of serotonin on ciliary beating and intracellular calcium concentration in identified populations of embryonic ciliary cells

“…It appears that Ca 2+ is either required to bind to a Ca 2+ -binding protein at the level of the cilium or is necessary in the activation of other signal transduction cascades that result in phosphorylation of a target protein within the cilium. The Ca 2+ -binding protein calmodulin has been shown in both invertebrates (Nakaoka et al, 1984) ionomycin Characterization of ciliary cell subpopulations Benedetto et al, 1991) to participate in mediating cilioexcitation. Likewise, in Helisoma ciliary cells, calmodulin appears to be a necessary component in the cilio-excitatory response to 5-HT, as the calcium/calmodulin-dependent enzyme inhibitor calmidazolium inhibited this response in unidentified ciliary cells.…”

“…However, changes in [Ca 2+ ]i appear to be a possible universal mechanism in altering CBF. Ca 2+ regulates ciliary activity in invertebrate systems, such as ctenophore larvae (Tamm and Terasaki, 1994), Paramecium (Eckert, 1972) and Mytilus edilus (Murakami and Machemer, 1982), and in almost all vertebrate systems examined, including the salamander Necturus maculosus (Murakami and Eckert, 1971), the frog esophagus (Levin et al, 1997), the rabbit trachea (Lansley and Sanderson, 1999) and human respiratory epithelium (Di Benedetto et al, 1991). It appears that Ca 2+ is either required to bind to a Ca 2+ -binding protein at the level of the cilium or is necessary in the activation of other signal transduction cascades that result in phosphorylation of a target protein within the cilium.…”

Interplay between the NO pathway and elevated [Ca2+]i enhances ciliary activity in rabbit trachea

“…â-Adrenergic agonists known to elevate the concentration of cAMP stimulate CBF of respiratory epithelia . cAMP-dependent modulation of CBF has been reported in human and rabbit ciliary cells (Tamaoki et al 1989;Di Benedetto et al 1991;Yang et al 1996). cAMPdependent protein kinase (PKA) has been shown to phosphorylate specific axonemal targets that increase the forward swimming speed in Paramecium (Hamasaki et al 1991).…”

“…Among these stimulators, extracellular ATP is the most potent activator of ciliary function, stimulating a variety of ciliary cells, including frog palate and oesophagus (Ovadyahu et al 1988;Weiss et al 1992), human nasal polyps (Mason et al 1991), rabbit oviduct (Villalon et al 1989), dog trachea (Wong & Yeates, 1992), and rabbit trachea (Korngreen & Priel, 1996). It is well known that the cellular event most closely implicated in ciliary stimulation is a change in [Ca¥]é (Verdugo, 1980;Villalon et al 1989;Di Benedetto et al 1991;Lansley et al 1992; Korngreen & Priel, 1994;Salathe & Bookman, 1995;Tarasiuk et al 1995). Recently, the correlation between ciliary beat frequency (CBF) and [Ca¥]é enhancement was systematically examined in ciliary cells from rabbit airway epithelia (Korngreen & Priel, 1996).…”

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

“…We recently reported such transient stimulatory effects of SP on human cilia [10] using a rather cumbersome photometric technique for the measurement of CBF [14], which has been superseded by video-based equipment [8]. Using this latter technique, we have now extended our studies on the mechanisms by which SP increases CBF.…”