Heritable formation of neuroectodermal tumor in transgenic mice carrying the combined E1 region gene of adenovirus type 12 with the deregulated human renin promoter

Development of genetically engineered mice with hypertension and hypotension

Human essential hypertension is generally recognized as a multifactorial disease involving the interplay of environmental factors based on genetic diathesis. Spontaneously hypertensive rats (SHR) and Dahl rats are widely used as animal models for human essential hypertension and salt-sensitive hypertension, respectively. The definitive genetic factor ruling the development of hypertension in these strains remains unclear, but recently advances in embryonic engineering and molecular biological techniques may make it possible for transgenic mice and gene-targeted mice to become important pathological models defined genetically and functionally for human disease. The author developed two types of genetically engineered mice that may serve as such models: a transgenic mouse with hypertension caused by enhancing the renin-angiotensin system and a gene-targeted mouse with hypotension caused by disrupting the renin-angiotensin system.

New aspects of the renin-angiotensin system in blood pressure regulation

The renin-angiotensin system, composed of enzymatic and signal-transduction cascades, plays a key role in the regulation of arterial blood pressure and in the development of certain forms of experimental and human hypertension. The products of this system, angiotensin peptides, exert a wide range of physiologically important effects on many tissues, including those of the cardiovascular system, through their actions on angiotensin receptors. Molecular genetic and transgenic studies have begun to implicate some of the genes encoding components of the renin-angiotensin system in the development of cardiovascular diseases. Recently, we succeeded in generating mice homozygous for a targeted disruption of the angiotensinogen gene (the only known precursor of angiotensins), resulting in the complete loss of angiotensin signals in vivo. Here, we review new developments related to the functional analysis of the renin-angiotensin system, in particular, by focusing on transgenic approaches including gene targeting.