Abstract
The natriuretic peptides, atrial (ANP) and brain natriuretic peptide (BNP) are known to suppress cardiac hypertrophy and fibrosis. Both ANP and BNP exert their bioactivities through the Npr1 receptor, and Npr1 knockout mice (Npr1-/-) exhibit marked cardiac hypertrophy and fibrosis. In this study, we investigated which genes within the hypertrophic and fibrotic pathways are influenced by the lack of Npr1 signalling. cDNA microarray and quantitative real-time PCR (RT-PCR) analyses were performed on cardiac ventricles from Npr1-/-mice. Gene expression at early and late stages during development of hypertrophy was investigated in male and female Npr1-/-mice at 8 weeks and 6 months of age. Heart weight to body weight ratios (HW:BW) were maximally increased in 8-week males (P<0 x 01), whilst HW:BW in females continued to increase progressively up to 6 months (P<0 x 01). This was despite blood pressure being similarly elevated at both the ages in male and female knockout when compared with wild-type (WT) mice (P<0 x 001). Microarray analysis identified altered gene expression at the earliest steps in the hypertrophy-signalling cascade in Npr1-/- mice, particularly calcium-calmodulin signalling and ion channels, with subsequent changes in the expression of intracellular messengers including protein kinases and transcription factors. Real-time PCR analysis confirmed significant differences in gene expression of ANP, BNP, calmodulin 1, histone deacetylase 7a (HDAC7a), protein kinase C (PKC)iota, (GATA) 4, collagen 1, phospholamban and transforming growth factor-beta1 in Npr1-/- mice when compared with WT (P<0 x 05). The present study implicates the calmodulin-CaMK-Hdac-Mef2 and PKC-MAPK-GATA4 pathways in Npr1 mediation of cardiac hypertrophy.
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
