Generation of Nppa‐tagBFP reporter knock‐in mouse line for studying cardiac chamber specification

Nppa is a cardiac hormone which plays critical roles in regulating salt–water balance. Its expression is restricted to the atria of the healthy post‐natal heart. During heart development, spatio‐temporal expression of Nppa is dynamically changed within the heart and becomes restricted to the atria upon birth. In contrast to its atrial specific expression after birth, Nppa is re‐expressed in the adult ventricles in response to cardiac hypertrophy. To study cardiac chamber specification during development and pathological cardiac remodeling during heart disease, we generated a novel Nppa reporter mouse line by knocking‐in a tagBFP reporter cassette into 3′‐UTR of the Nppa gene without disrupting the endogenous gene. Our results demonstrated dynamic tagBFP expression in the developing heart, recapitulating the spatiotemporal expression pattern of endogenous Nppa. We also found that Nppa‐tagBFP is induced in the ventricle during pathological remodeling. Taken together, Nppa‐tagBFP reporter knock‐in mouse model described in this article will serve as a valuable tool to study cardiac chamber specification during development as well as pathological cardiac remodeling.     

Identification and gene expression analyses of natriuretic peptide system in the ovary of goat (Capra hircus)

Natriuretic peptides (NPs) are involved in maintaining cardiovascular and fluid homeostasis, regulating reproductive processes and bone growth, and other numerous functions. To better understand the role of NPs in goat (Capra hircus), in the present study, full-length cDNAs of goat Nppa (natriuretic peptide precursor A), Nppb (natriuretic peptide precursor B) and Nppc (natriuretic peptide precursor C), respectively encoding ANP, BNP and CNP, were cloned from adult goat heart and ovary. The putative prepropeptide ANP (prepro-ANP) and prepro-CNP share a high amino acid sequence identity with other species. Real-time PCR showed that Nppa, Nppb and Nppc were widely expressed in adult goat tissues. The mRNA expression of Nppa and Nppb in the heart was extremely higher compared with other tissues. Nppc mRNA expression in the lung and uterus was also higher than in other tissues. The expression of Nppa, Nppb and Nppc genes was examined at different ovarian follicle stages using RT-PCR. The mRNAs of Nppa and Nppb were detected in secondary follicles as well as in COCs (cumulus–oocyte-complexes) and granulosa cells of antral follicles. However, the mRNA expression of Nppc was observed throughout ovarian follicle development, and it was especially higher in granulosa cells of antral follicles. In vitro, stimulating goat granulosa cells with FSH led to an increase in the expression of Nppc by dose- and time-dependent manners and a rapid decline was induced by LH stimulation, but the expression of Nppa and Nppb did not change after FSH or LH treatment. These results suggest that Nppc is a gonadotropin-induced gene in granulosa cells of goat ovary and CNP may be involved in the regulation of ovarian follicle development and oocyte maturation.