Presence of the Ca<sup>2+</sup>-activated chloride channel anoctamin 1 in the urethra and its role in excitatory neurotransmission

Sancho, María; Garcia-Pascual, Angeles; Triguero, Domingo

doi:10.1152/ajprenal.00344.2011

Cited by 20 publications

(15 citation statements)

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“…The CaCC anoctamin-1 (Ano1) genetically encoded by Tmem16a has been identified as the molecular correlate of the pacemaking conductance in the GI tract [31,69]. Ano1 expression has also been reported in the urethra of mice, rats and sheep; although here it was detected on smooth muscle and urothelial cells, but not on vimentin-positive ICC [80]. Cl -entry through Ano1 channels appears critical for generation of slow waves and corresponding contractile activity of the oviduct as, unlike their wild-type littermates, neonatal mice homozygous for a null allele of Tmem16a lack electrical slow wave activity in the myosalpinx [17].…”

Section: -Conductances and Uterine Pacemaker Eventsmentioning

confidence: 69%

Uterine Contractility in the Nonpregnant Mouse: Changes During the Estrous Cycle and Effects of Chloride Channel Blockade1

Dodds

Staikopoulos

Beckett

2015

Biology of Reproduction

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Mechanisms involved in the generation of spontaneous uterine contractions are not fully understood. Kit-expressing interstitial cells of Cajal are pacemakers of contractile rhythm in other visceral organs, and recent studies describe a role for Ca(2+)-activated Cl(-) currents as the initiating conductance in these cells. The existence and role of similar specialized pacemaker cells in the nonpregnant uterus remains undetermined. Spontaneous contractility patterns were characterized throughout the estrous cycle in isolated, nonpregnant mouse uteri using spatiotemporal mapping and tension recordings. During proestrus, estrus, and diestrus, contraction origin predominated in the oviduct end of the uterus, suggesting the existence of a dominant pacemaker site. Propagation speed of contractions during estrus and diestrus were significantly slower than in proestrus and metestrus. Five major patterns of activity were predominantly exhibited in particular stages: quiescent (diestrus), high-frequency phasic (proestrus), low-frequency phasic (estrus), multivariant (metestrus), and complex. Kit-immunopositive cells reminiscent of pacemaking ICCs were not consistently observed within the uterus. Niflumic acid (10 μM), anthracene-9-carboxylic acid (0.1-1 mM), and 5-nitro-2-(3-phenylpropylamino)benzoic acid (10 μM) each reduced the frequency of spontaneous contractions, suggesting involvement of Cl(-) channels in generating spontaneous uterine motor activity. It is unlikely that this conductance is generated by the Ca(2+)-activated Cl(-) channels, anoctamin-1 and CLCA4, as immunohistochemical labeling did not reveal protein expression within muscle or pacemaker cell networks. In summary, these results suggest that spontaneous uterine contractions may be generated by a Kit-negative pacemaker cell type or uterine myocytes, likely involving the activity of a yet-unidentified Cl(-) channel.

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Section: -Conductances and Uterine Pacemaker Eventsmentioning

confidence: 69%

Uterine Contractility in the Nonpregnant Mouse: Changes During the Estrous Cycle and Effects of Chloride Channel Blockade1

Dodds

Staikopoulos

Beckett

2015

Biology of Reproduction

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“…Subsequent work in various smooth muscle beds has demonstrated that ANO 1 serves a fundamental role in organizing smooth muscle contraction. In particular, ANO 1 mediated chloride current has been shown to alter cell membrane depolarization and slow waves in the GI tract [12, 13], urethra [14], and oviduct [15]. Additionally, ANO 1 is functionally expressed in airway smooth muscle and its blockade attenuates contractions as well as pro-contractile membrane associated currents [16, 17].…”

Section: Introductionmentioning

confidence: 99%

Calcium-activated chloride channels anoctamin 1 and 2 promote murine uterine smooth muscle contractility

Bernstein

Vink

et al. 2014

American Journal of Obstetrics and Gynecology

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Objective To determine the presence of calcium activated chloride channels anoctamin 1 and 2 in human and murine uterine smooth muscle and evaluate the physiologic role for these ion channels in murine myometrial contractility. Study Design We performed reverse transcription polymerase chain reaction to determine if anoctamin 1 and 2 are expressed in human and murine uterine tissue to validate the study of this protein in mouse models. Immunohistochemical staining of anoctamin 1 and 2 was then performed to determine protein expression in murine myometrial tissue. The function of anoctamin 1 and 2 in murine uterine tissue was evaluated using electrophysiological studies, organ bath, and calcium flux experiments. Results Anoctamin 1 and 2 are expressed in human and murine USM cells. Functional studies show that selective antagonism of these channels promotes relaxation of spontaneous murine uterine smooth muscle contractions. Blockade of anoctamin 1 and 2 inhibits both agonist-induced and spontaneous transient inward currents and abolishes G-protein coupled receptor (oxytocin) mediated elevations in intracellular calcium. Conclusion The calcium activated chloride channels ANO 1 and 2 are present in human and murine myometrial tissue and may provide novel potential therapeutic targets to achieve effective tocolysis.

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“…TMEM16A and TMEM16B channels serve a variety of functions in many cell types, including secretory epithelia (5)(6)(7)(8), gastrointestinal pacemakers (9), sensory neurons and hippocampal neurons (10)(11)(12)(13), urethral and vascular smooth muscle (14,15), and tumor cells (16). Hence, it is important to understand how these channels work.…”

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confidence: 99%

Four basic residues critical for the ion selectivity and pore blocker sensitivity of TMEM16A calcium-activated chloride channels

Peters¹,

Tien³

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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TMEM16A (transmembrane protein 16) (Anoctamin-1) forms a calcium-activated chloride channel (CaCC) that regulates a broad array of physiological properties in response to changes in intracellular calcium concentration. Although known to conduct anions according to the Eisenman type I selectivity sequence, the structural determinants of TMEM16A anion selectivity are not well-understood. Reasoning that the positive charges on basic residues are likely contributors to anion selectivity, we performed whole-cell recordings of mutants with alanine substitution for basic residues within the putative pore region and identified four residues on four different putative transmembrane segments that significantly increased the permeability of the larger halides and thiocyanate relative to that of chloride. Because TMEM16A permeation properties are known to shift with changes in intracellular calcium concentration, we further examined the calcium dependence of anion selectivity. We found that WT TMEM16A but not mutants with alanine substitution at those four basic residues exhibited a clear decline in the preference for larger anions as intracellular calcium was increased. Having implicated these residues as contributing to the TMEM16A pore, we scrutinized candidate small molecules from a high-throughput CaCC inhibitor screen to identify two compounds that act as pore blockers. Mutations of those four putative porelining basic residues significantly altered the IC 50 of these compounds at positive voltages. These findings contribute to our understanding regarding anion permeation of TMEM16A CaCC and provide valuable pharmacological tools to probe the channel pore.calcium-activated channels | chloride channels | channel pharmacology | TMEM16A | ion channel biophysics

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Presence of the Ca²⁺-activated chloride channel anoctamin 1 in the urethra and its role in excitatory neurotransmission

Abstract: Sancho M, García-Pascual A, Triguero D. Presence of the Ca 2ϩ -activated chloride channel anoctamin 1 in the urethra and its role in excitatory neurotransmission.

Cited by 20 publications

References 35 publications

Uterine Contractility in the Nonpregnant Mouse: Changes During the Estrous Cycle and Effects of Chloride Channel Blockade1

Uterine Contractility in the Nonpregnant Mouse: Changes During the Estrous Cycle and Effects of Chloride Channel Blockade1

Calcium-activated chloride channels anoctamin 1 and 2 promote murine uterine smooth muscle contractility

Four basic residues critical for the ion selectivity and pore blocker sensitivity of TMEM16A calcium-activated chloride channels

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Presence of the Ca2+-activated chloride channel anoctamin 1 in the urethra and its role in excitatory neurotransmission

Abstract: Sancho M, García-Pascual A, Triguero D. Presence of the Ca 2ϩ -activated chloride channel anoctamin 1 in the urethra and its role in excitatory neurotransmission.

Cited by 20 publications

References 35 publications

Uterine Contractility in the Nonpregnant Mouse: Changes During the Estrous Cycle and Effects of Chloride Channel Blockade1

Uterine Contractility in the Nonpregnant Mouse: Changes During the Estrous Cycle and Effects of Chloride Channel Blockade1

Calcium-activated chloride channels anoctamin 1 and 2 promote murine uterine smooth muscle contractility

Four basic residues critical for the ion selectivity and pore blocker sensitivity of TMEM16A calcium-activated chloride channels

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Presence of the Ca²⁺-activated chloride channel anoctamin 1 in the urethra and its role in excitatory neurotransmission