Physiological induction of transient receptor potential canonical proteins, calcium entry channels, in human myometrium:: Influence of pregnancy, labor, and interleukin-1β

This study investigated gestational regulation of transient receptor potential canonical (TrpC) proteins, putative calcium entry channels in human myometrium, and the potential modulation of TrpC expression by IL-1beta, a cytokine implicated in labor. Total RNA and proteins were isolated from myometrial biopsies obtained from NP women, pregnant women at term not in labor (TNL), or term active labor ( TAL) and from primary cultured human myometrial smooth muscle cells incubated with IL-1beta or IL-1beta with or without nimesulide. Semiquantitative RT-PCR demonstrated significant upregulation of TrpC1 in TAL and TNL ( P less than or equal to 0.01) and TrpC6 ( P less than or equal to 0.01) and TrpC7 ( P less than or equal to 0.05) in TAL samples. TrpC3 and TrpC4 mRNA expression was unaffected. Western blot demonstrated significant up-regulation of TrpC1 in TAL and TNL ( P less than or equal to 0.05) and TrpC3 ( P less than or equal to 0.01), TrpC4 ( P less than or equal to 0.05), and TrpC6 ( P less than or equal to 0.01) in TAL samples. IL-1beta did not alter TrpC1, 3, 4, 6, or 7 mRNA expression; but IL-1beta exclusively up-regulated TrpC3 protein expression ( P less than or equal to 0.05). TrpC3 up-regulation was unaffected by cyclooxygenase blockade. These data demonstrate physiological regulation of TrpC mRNA and protein and suggest an important role for TrpC proteins in human myometrium during labor.