Carnitine palmitoyltransferase 1A is essential for decidualization in mice

Decidualization accompanies with extensive stromal cell proliferation and differentiation, is a crucial step in early pregnancy. Aberrant decidualization is linked to infertility and miscarriage but the mechanisms remain unclear. Carnitine palmitoyltransferase 1A (CPT1A) is an enzyme catalyzing key steps in the fatty acid beta-oxidation pathway. The objective of this study was to investigate the role of CPT1A in decidualization during early pregnancy. An increased expression of CPT1A was found both in Days 6 and 7 as compared with in Days 1, 4 and 5. Further examination showed that on days 5-7 of pregnancy, the protein level of CPT1A was strongly up-regulated at implantation sites compared with inter-implantation sites, the location of CPT1A protein was distributed in the decidual zone. Upon further exploration, CPT1A expression was significantly increased in response to artificially induced decidualization both in vivo and in vitro. After down-regulating CPT1A expression by CPT1A-small interfering RNA (siCPT1A) in primary mouse endometrial stromal cells, expressions of decidualization markers and cell proliferation markers were decreased. After siCPT1A was transfected into the mouse uterus, decidualization impaired and then led to the loss of the implanted embryos. Thus, CPT1A is important for decidualization in mice and it may regulate the stromal cell proliferation progress. It is worth noting that the expression of CPT1A protein of human decidua was significantly decreased in spontaneous abortion groups compared to normal pregnancy groups. Collectively, CPT1A is essential for endometrium of early pregnant mice and humans.