Two‐dimensional electrophoretic mapping of hepatic and renal stress proteins

Abstract

Cellular stress proteins and molecular chaperones are responsive to a variety of stressors and therefore comprise an ideal set of proteins with the potential to be used as biomarkers of chemical toxicity. We have investigated the expression of a group of well established heat shock and glucose-regulated proteins in the rat liver and kidney using large-scale two-dimensional protein electrophoresis and computerized image analysis. Our goal was to determine the level of their expression in unstressed target tissues and map their coordinate positions on conventional format two-dimensional electrophoresis (2-DE) gels. All the proteins studied, except for Hsp25 (heat-shock protein) whose expression fell below the level of analyzable detection, were constitutively expressed in liver and kidney. With the exception of Hsp70, all the stress proteins analyzed were constitutively more abundant in the liver than the kidney. Comparison of the sum total of all stress protein abundances revealed a nearly threefold higher level of expression in the liver than the kidney. Our results suggest that this group of proteins has significant responsibilities in normal, unstressed cells, due to their constitutive abundance. Correspondingly, the 2-DE stress protein pattern established in this study may be very useful in toxicologic screening as well as describing a broad range of molecular effects of xenobiotic exposure.

The atrial natriuretic peptide and cGMP: Novel activators of the heat shock response in rat livers

“…37 An up-regulation of HSP70 during reperfusion was observed mainly after warm ischemia, 38 thereby representing a different pathophysiologic setting. Schutz et al, performing cold ischemia in a pig model, determined HSP70 mRNA expression only without investigating HSP70 protein concentrations.…”

Protein Markers of Chemical Exposure and Molecular Epidemiology

“…Animals were dosed on a mg/kg basis as follows: 260, 360, or 1300 ug/kg lead to achieve targeted blood levels of 20, 40 or 80 ug/dL. Following the loading dose period, rabbits were then placed on a maintenance dose solutions during study weeks [11][12][13][14][15][16][17][18][19][20] Dayton OH. Warm and cold ischemic times were 10 and 50 min, respectively.…”

“…Because the cortex is the primary site of filtration and filtrate reabsorption and the medulla is the site of renal filtrate concentrating mechanisms, it's not surprising to find that the two regions are constitutively different [12,13] and that these regions are differentially susceptible to toxic exposure [14,15]. Examining the effect of xenobiotic exposure on the expression of whole kidney homogenate protein patterns, as we have done previously [16,17], may not accurately reflect potential regiospecific changes. This is particularly true if these protein alterations are regionally diametrical, and thus may actually minimize or mask one another and be overlooked in analyzing a whole tissue homogenate.…”

Stress Response in a Leporine Renal Cell Model

“…However, deficient cytoprotection by HSP70 [7] or low HSP levels in kidney relative to other organs [8, 14] could explain the marked sensitivity of RPT cells to various modes of injury. RPT cells grown under SHAKE conditions tend to preserve their in vivo characteristics [20] and respond to heat stress through upregulation of HSP70.…”

“…In particular, susceptibility of renal proximal tubule (RPT) cells to various toxic agents could be related to a limited capacity for mounting a cellular stress response [7, 8], although the expression of certain HSPs is elevated in numerous renal disease states [9, 10, 11, 12, 13]. Constitutive HSP levels in kidney, however, may be quite low and with the possible exception of HSP70 may be significantly lower than those in liver, for example [14]. …”