title: Transepithelial calcium transport in prolactin-exposed intestine-like Caco-2 monolayer after combinatorial knockdown of TRPV5, TRPV6 and Ca(v)1.3.
abstract: The milk-producing hormone prolactin (PRL) increases the transcellular intestinal calcium absorption by enhancing apical calcium uptake through voltage-dependent L-type calcium channel (Ca(v)) 1.3. However, the redundancy of apical calcium channels raised the possibility that Ca(v)1.3 may operate with other channels, especially transient receptor potential vanilloid family calcium channels (TRPV) 5 or 6, in an interdependent manner. Herein, TRPV5 knockdown (KD), TRPV5/TRPV6, TRPV5/Ca(v)1.3, and TRPV6/Ca(v)1.3 double KD, and TRPV5/TRPV6/Ca(v)1.3 triple KD Caco-2 monolayers were generated by transfecting cells with small interfering RNAs (siRNA). siRNAs downregulated only the target mRNAs, and did not induce compensatory upregulation of the remaining channels. After exposure to 600 ng/mL PRL, the transcellular calcium transport was increased by ~2-fold in scrambled siRNA-treated, TRPV5 KD and TRPV5/TRPV6 KD monolayers, but not in TRPV5/Ca(v)1.3, TRPV6/Ca(v)1.3 and TRPV5/TRPV6/Ca(v)1.3 KD monolayers. The results suggested that Ca(v)1.3 was the sole apical channel responsible for the PRL-stimulated transcellular calcium transport in intestine-like Caco-2 monolayer.
authors.affiliation: Consortium for Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand.
authors.forename: La-iad
authors.initials: LI
authors.lastname: Nakkrasae
authors.forename: Narongrit
authors.initials: N
authors.lastname: Thongon
authors.forename: Jirawan
authors.initials: J
authors.lastname: Thongbunchoo
authors.forename: Nateetip
authors.initials: N
authors.lastname: Krishnamra
authors.forename: Narattaphol
authors.initials: N
authors.lastname: Charoenphandhu
mesh_terms: D018938:Caco-2 Cells; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism / Q000502:physiology; D020746:Calcium Channels, L-Type / Q000502:physiology*; D055785:Gene Knockdown Techniques; D006801:Humans; D011388:Prolactin / Q000494:pharmacology; D050916:TRPV Cation Channels / Q000502:physiology
chemical_list: C472073:CACNA1D protein, human; D015220:Calcium Channels; D020746:Calcium Channels, L-Type; D050916:TRPV Cation Channels; C492239:TRPV5 protein, human; C422827:TRPV6 protein, human; D011388:Prolactin; D002118:Calcium