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Isolated human uterine telocytes: immunocytochemistry and electrophysiology of T-type calcium channels.

Cretoiu SM, Radu BM, Banciu A, Banciu DD, Cretoiu D, Ceafalan LC, Popescu LM - Histochem. Cell Biol. (2014)

Bottom Line: It is suggested that TCs play a major role in intercellular signaling, as well as in morphogenesis, especially in morphogenetic bioelectrical signaling.The expression in TCs from the non-pregnant myometrium is less intense, being confined to the cell body for CaV3.2, while CaV3.1 was expressed both on the cell body and in Tps.In conclusion, our results show that T-type calcium channels are present in TCs from human myometrium and could participate in the generation of endogenous bioelectric signals responsible for the regulation of the surrounding cell behavior, during pregnancy and labor.

View Article: PubMed Central - PubMed

Affiliation: Division of Cell Biology and Histology, Carol Davila University of Medicine and Pharmacy, 050474, Bucharest, Romania, sanda@cretoiu.ro.

ABSTRACT
Recently, telocytes (TCs) were described as a new cell type in the interstitial space of many organs, including myometrium. TCs are cells with very long, distinctive extensions named telopodes (Tps). It is suggested that TCs play a major role in intercellular signaling, as well as in morphogenesis, especially in morphogenetic bioelectrical signaling. However, TC plasma membrane is yet unexplored regarding the presence and activity of ion channels and pumps. Here, we used a combination of in vitro immunofluorescence and patch-clamp technique to characterize T-type calcium channels in TCs. Myometrial TCs were identified in cell culture (non-pregnant and pregnant myometrium) as cells having very long Tps and which were positive for CD34 and platelet-derived growth factor receptor-α. Immunofluorescence analysis of the subfamily of T-type (transient) calcium channels CaV3.1 and CaV3.2 presence revealed the expression of these ion channels on the cell body and Tps of non-pregnant and pregnant myometrium TCs. The expression in TCs from the non-pregnant myometrium is less intense, being confined to the cell body for CaV3.2, while CaV3.1 was expressed both on the cell body and in Tps. Moreover, the presence of T-type calcium channels in TCs from non-pregnant myometrium is also confirmed by applying brief ramp depolarization protocols. In conclusion, our results show that T-type calcium channels are present in TCs from human myometrium and could participate in the generation of endogenous bioelectric signals responsible for the regulation of the surrounding cell behavior, during pregnancy and labor.

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Electrophysiological activity recorded in TCs from non-pregnant myometrium. a TC visualized by transmitted light microscopy in phase-contrast illumination mode during patch-clamp recording. b TCs generated no detectable voltage-activated calcium currents when tested with a step depolarization protocol. The same protocol was applied on n = 12 TCs. Inset Step depolarization protocol of 100 ms duration from −90 to +40 mV incremented by 10-mV steps, from a holding potential of −110 mV. c Representative T-type calcium current and HVA current in a TC (black line) and the blocking effect of 1 μM mibefradil on Ca2+ currents (red line). Inset Ramp commands of 100 ms duration from −90 to +60 mV in voltage-clamp mode. d Current amplitude of T-type and HVA calcium currents in control and mibefradil exposure conditions expressed as mean ± SD (n = 4)
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Fig5: Electrophysiological activity recorded in TCs from non-pregnant myometrium. a TC visualized by transmitted light microscopy in phase-contrast illumination mode during patch-clamp recording. b TCs generated no detectable voltage-activated calcium currents when tested with a step depolarization protocol. The same protocol was applied on n = 12 TCs. Inset Step depolarization protocol of 100 ms duration from −90 to +40 mV incremented by 10-mV steps, from a holding potential of −110 mV. c Representative T-type calcium current and HVA current in a TC (black line) and the blocking effect of 1 μM mibefradil on Ca2+ currents (red line). Inset Ramp commands of 100 ms duration from −90 to +60 mV in voltage-clamp mode. d Current amplitude of T-type and HVA calcium currents in control and mibefradil exposure conditions expressed as mean ± SD (n = 4)

Mentions: The presence of T-type calcium channels in TCs was tested by the patch-clamp technique (Fig. 5a) in voltage-clamp mode, using brief ramp depolarization protocol (Fig. 5b, upper insert) and step-depolarizing pulse protocol (Fig. 5c, upper insert).Fig. 5


Isolated human uterine telocytes: immunocytochemistry and electrophysiology of T-type calcium channels.

Cretoiu SM, Radu BM, Banciu A, Banciu DD, Cretoiu D, Ceafalan LC, Popescu LM - Histochem. Cell Biol. (2014)

Electrophysiological activity recorded in TCs from non-pregnant myometrium. a TC visualized by transmitted light microscopy in phase-contrast illumination mode during patch-clamp recording. b TCs generated no detectable voltage-activated calcium currents when tested with a step depolarization protocol. The same protocol was applied on n = 12 TCs. Inset Step depolarization protocol of 100 ms duration from −90 to +40 mV incremented by 10-mV steps, from a holding potential of −110 mV. c Representative T-type calcium current and HVA current in a TC (black line) and the blocking effect of 1 μM mibefradil on Ca2+ currents (red line). Inset Ramp commands of 100 ms duration from −90 to +60 mV in voltage-clamp mode. d Current amplitude of T-type and HVA calcium currents in control and mibefradil exposure conditions expressed as mean ± SD (n = 4)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4286651&req=5

Fig5: Electrophysiological activity recorded in TCs from non-pregnant myometrium. a TC visualized by transmitted light microscopy in phase-contrast illumination mode during patch-clamp recording. b TCs generated no detectable voltage-activated calcium currents when tested with a step depolarization protocol. The same protocol was applied on n = 12 TCs. Inset Step depolarization protocol of 100 ms duration from −90 to +40 mV incremented by 10-mV steps, from a holding potential of −110 mV. c Representative T-type calcium current and HVA current in a TC (black line) and the blocking effect of 1 μM mibefradil on Ca2+ currents (red line). Inset Ramp commands of 100 ms duration from −90 to +60 mV in voltage-clamp mode. d Current amplitude of T-type and HVA calcium currents in control and mibefradil exposure conditions expressed as mean ± SD (n = 4)
Mentions: The presence of T-type calcium channels in TCs was tested by the patch-clamp technique (Fig. 5a) in voltage-clamp mode, using brief ramp depolarization protocol (Fig. 5b, upper insert) and step-depolarizing pulse protocol (Fig. 5c, upper insert).Fig. 5

Bottom Line: It is suggested that TCs play a major role in intercellular signaling, as well as in morphogenesis, especially in morphogenetic bioelectrical signaling.The expression in TCs from the non-pregnant myometrium is less intense, being confined to the cell body for CaV3.2, while CaV3.1 was expressed both on the cell body and in Tps.In conclusion, our results show that T-type calcium channels are present in TCs from human myometrium and could participate in the generation of endogenous bioelectric signals responsible for the regulation of the surrounding cell behavior, during pregnancy and labor.

View Article: PubMed Central - PubMed

Affiliation: Division of Cell Biology and Histology, Carol Davila University of Medicine and Pharmacy, 050474, Bucharest, Romania, sanda@cretoiu.ro.

ABSTRACT
Recently, telocytes (TCs) were described as a new cell type in the interstitial space of many organs, including myometrium. TCs are cells with very long, distinctive extensions named telopodes (Tps). It is suggested that TCs play a major role in intercellular signaling, as well as in morphogenesis, especially in morphogenetic bioelectrical signaling. However, TC plasma membrane is yet unexplored regarding the presence and activity of ion channels and pumps. Here, we used a combination of in vitro immunofluorescence and patch-clamp technique to characterize T-type calcium channels in TCs. Myometrial TCs were identified in cell culture (non-pregnant and pregnant myometrium) as cells having very long Tps and which were positive for CD34 and platelet-derived growth factor receptor-α. Immunofluorescence analysis of the subfamily of T-type (transient) calcium channels CaV3.1 and CaV3.2 presence revealed the expression of these ion channels on the cell body and Tps of non-pregnant and pregnant myometrium TCs. The expression in TCs from the non-pregnant myometrium is less intense, being confined to the cell body for CaV3.2, while CaV3.1 was expressed both on the cell body and in Tps. Moreover, the presence of T-type calcium channels in TCs from non-pregnant myometrium is also confirmed by applying brief ramp depolarization protocols. In conclusion, our results show that T-type calcium channels are present in TCs from human myometrium and could participate in the generation of endogenous bioelectric signals responsible for the regulation of the surrounding cell behavior, during pregnancy and labor.

Show MeSH
Related in: MedlinePlus