The Deletion of TRPC6 Channels Perturbs Iron and Zinc Homeostasis and Pregnancy Outcome in Mice.

BACKGROUND/AIMS: Transient receptor potential canonical 6 (TRPC6) protein is a nonselective cation channel permitting the uptake of essential elements such as iron (Fe) and zinc (Zn). TRPC6 is found throughout the body with high expression levels in the placenta. However, its role in this organ is still to be determined. To further advance our understanding of the physiological relevance of TRPC6, we have studied the placental histology, pregnancy outcome and the Fe and Zn status of organs (placenta, brain, kidney, liver and lung) collected from TRPC6 deficient (TRPC6-/-) mice and sex and age-matched C57Bl6/J and B6129SF2/J mice.

METHODS: Metal content was quantified by inductively coupled plasma-atomic emission spectrometry (ICP-AES). Quantitative reverse transcriptase PCR (qRT-PCR) and Western Blottings (WB) were performed to analyze the expression of placental markers and TRPC6.

RESULTS: Our data show that TRPC6-/- mice displayed reduced litter sizes, structural changes of the placenta, along with altered mRNA levels of CD31 and Gcm1, two markers of placental development. Furthermore, immunoblots revealed elevated amounts of TRPC6 proteins in placentas from women diagnosed with preeclampsia, a common gestational disease. When compared to C57Bl6/J and B6129SF2/J, TRPC6-/- mice had elevated Zn levels in placenta, liver and kidney during embryonic development and postnatally, but not at adulthood. High amounts of Fe were found in the adult brain and liver of TRPC6-/- mice. The lung was however not affected by the deletion of TRPC6, indicating that this mouse strain developed organ and age-dependent perturbations in their Zn and Fe status.

CONCLUSION: This work indicates that TRPC6 exerts critical pathophysiological functions in placenta, and provides further evidence for a role of this channel in the homeostasis of cations like Zn and Fe.