Gap junctional intercellular communication in the juxtaglomerular apparatus

Abstract

The juxtaglomerular apparatus (JGA) is a specialized contact region between the glomerulus and the cortical thick ascending limb that plays an active role in the maintenance of ion homeostasis and control of blood pressure. The JGA accommodates several different cell types, including vascular smooth muscle cells, endothelial cells, mesangial cells, macula densa cells, and renin-secreting juxtaglomerular granular cells. These cells, with the exception of the macular densa cells, are tightly coupled by gap junctions. Gap junction-mediated intercellular communication in the JGA provides a pathway for signal transduction and coordination of multicellular functions. Disruption of cell-to-cell communication in the JGA results in altered preglomerular vascular tone and renin secretion. This review summarizes recent data about the roles of gap junctions in the JGA and illustrates how gap junction-mediated intercellular Ca2+signals determine physiological responses in the JGA.

Changes in renal vessels following the long-term administration of an angiotensin II receptor blocker in Zucker fatty rats

“…Increased renin-producing granular cells and the SMCs of afferent arterioles stem from vascular SMCs, and function with close communication, 7,33 but the factor causing SMCs to proliferate is unclear. In recent years, a pathway from AII to AIII and then a pathway to angiotensin IV leading toward cell proliferation and hypertrophy were discovered.…”

Intercellular Ca2+Waves: Mechanisms and Function

“…Because cilia are more effective at moving mucus when beating in coordinated groups, this behavior supports the idea that ICWs serve to coordinate tissue responses. Numerous other coordinating functions for ICWs have been proposed; these include proliferation or differentiation of keratinocytes (379), upstream signaling in the blood vessel wall (180,362), signaling between smooth muscle cells (141), and signaling between endothelial cells and smooth muscle cells via myoendothelial gap junctions to control vascular tone (170), communication between various cells in the juxtaglomerular apparatus mediating tubuloglomerular feedback (333,403), and regulation of metabolic activity of glial cells (21, 258). ICWs have also been proposed to provide communication between different cell types, for example, glial-neuron interactions in the brain, endothelial-glial interactions at the blood-brain barrier, and endothelial-smooth muscle cell communication in the vasculature (TABLE 1).…”

Gap Junctions

“…Interestingly, although knockin of Cx45 into the Cx40 locus is unable to rescue propagation of the vasomotor activity (Wolfle et al 2007), it abrogates the hyperreninemia, partially attenuating the systemic hypertension and restoring angiotensin-suppression of renin release (Schweda et al 2008). Parenthetically, Cx45 deletion from smooth muscle in the juxtaglomerular apparatus later in development also results in increased renin secretion and significant blood pressure elevation (Hanner et al 2008;Yao et al 2008).…”