Journal Article

Genetic regulation of catecholamine synthesis, storage and secretion in the spontaneously hypertensive rat

M.L. Jirout, R.S. Friese, N.R. Mahapatra, M. Mahata, L. Taupenot, S.K. Mahata, V. Křen, V. Zídek, J. Fischer, H. Maatz, M.G. Ziegler, M. Pravenec, N. Hubner, T.J. Aitman, N.J. Schork and D.T. O'Connor

in Human Molecular Genetics

Volume 19, issue 13, pages 2567-2580
Published in print July 2010 | ISSN: 0964-6906
Published online April 2010 | e-ISSN: 1460-2083 | DOI: http://dx.doi.org/10.1093/hmg/ddq135
Genetic regulation of catecholamine synthesis, storage and secretion in the spontaneously hypertensive rat

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Understanding catecholamine metabolism is crucial for elucidating the pathogenesis of hereditary hypertension. Here we integrated transcriptional and biochemical profiling with physiologic quantitative trait locus (eQTL and pQTL) mapping in adrenal glands of the HXB/BXH recombinant inbred (RI) strains, derived from the spontaneously hypertensive rat (SHR) and normotensive Brown Norway (BN.Lx). We found simultaneous down-regulation of five heritable transcripts in the catecholaminergic pathway in young (6 weeks) SHRs. We identified cis-acting eQTLs for Dbh, Pnmt (catecholamine biosynthesis) and Vamp1 (catecholamine secretion); enzymatic activities of Dbh and Pnmt paralleled transcripts, with pQTLs for activities mirroring eQTLs. We also detected trans-regulated expression of Vmat1 and Chga (both involved in catecholamine storage), with co-localization of these trans-eQTLs to the Pnmt locus. Pnmt re-sequencing revealed promoter polymorphisms that result in decreased response of the transfected SHR promoter to glucocorticoid, compared with BN.Lx. Of physiological pertinence, Dbh activity negatively correlated with systolic blood pressure in RI strains, whereas Pnmt activity was negatively correlated with heart rate. The finding of such cis- and trans-QTLs at an age before the onset of frank hypertension suggests that these heritable changes in biosynthetic enzyme expression represent primary genetic mechanisms for regulation of catecholamine action and blood pressure control in this widely studied model of hypertension.

Journal Article.  9224 words.  Illustrated.

Subjects: Genetics and Genomics

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