Localization of p35 (annexin I, lipocortin I) in normal adult rat kidney and during recovery from ischemia

Abstract

The 35-kDa protein (p35, lipocortin I, annexin I), originally discovered as a Ca(++)-dependent substrate for the EGF receptor tyrosine kinase, binds Ca++ and phospholipids, is developmentally regulated in embryos and has restricted expression in adults. Immunohistochemistry of normal rat kidney shows that p35 is enriched in epithelia of Bowman's capsule, the macula densa, and medullary/papillary collecting ducts, suggesting that p35 is related to specialized renal functions. Light staining is observed in the thick ascending limb; elsewhere, immunoreactivity is nil. Since renal recovery from ischemia involves both hyperplasia and hypertrophy and reportedly is accelerated by EGF, we examined p35 distribution during this process. After 48 hours of recovery, both the distribution and amount of renal p35 are altered. Immunoblots show p35 levels increased at least threefold in whole-kidney homogenates. The expression of p35 is still highly restricted in recovering kidneys; however, the thick ascending limb now stains heavily. This is the first documentation of alterations in annexin levels during a pathophysiologic response. However, our attempts to discern effects of exogenous EGF on the recovery from ischemia were negative for both mitotic index and renal function assays.

Annexin A1 protein attenuates cyclosporine-induced renal hemodynamics changes and macrophage infiltration in rats

“…In a normal kidney ANXA1 is mainly found in Bowman's capsule epithelium, macula densa and medullary and papillary collecting ducts, with light staining at the thick ascending limb. After ischemia/reperfusion, ANXA1 renal tissue expression increases significantly [42], as observed in the present study. These data suggest that endogenous ANXA1 increase might be an attempt to protect cell function and structure against ischemia reperfusion injury [43].…”

Immunohistochemical Localization of Lipocortin 1 in Rat Brain Is Sensitive to pH, Freezing, and Dehydration

“…These polyclonal antisera are effective at 1:8000 dilution, they identify LC1-ir in identical cell types in both frozen and paraffin sections, and the staining is completely abolished by pre-incubation with purified LC1. Studies in kidney have shown that pathophysiological changes in levels of LC1-ir quantified in tissue sections corresponded precisely with levels measured from immunoblot (Western) analysis (McKanna et al 1992).…”

“…Mean density on a scale of 0-255 was determined for Ͼ 50 cells per specimen and was standardized as a percentage of the density range defined by the kidney specimen on the same slide. Because previous studies (McKanna et al 1992) have demonstrated consistently strong LC1-ir in the medullary collecting ducts of normal rat kidney, the density of this staining was taken as 100% and assigned a rank of 4 ϩ ; unstained regions of the kidney cortex defined the density of background (0% ϭ Ϫ ). Other ranks were assigned from intervals on a linear scale from these endpoints: Ͻ 10%, Ϫ ; 10-20%, ϩ / Ϫ ; 21-40%, ϩ ; 41-60%, 2 ϩ ; 61-80%, 3 ϩ ; and 81-100%, 4 ϩ .…”

“…As a possible key to the functions of EGF in situ, we have studied immunohistochemical localization of LC1 in embryonic development and in pathophysiological responses (McKanna et al 1992;McKanna and Cohen 1989). It became apparent that LC1 immunoreactivity (LC1-ir) is very sensitive to fixation conditions.…”

Production of heparin binding epidermal growth factor-like growth factor in the early phase of regeneration after acute renal injury. Isolation and localization of bioactive molecules.

“…Ischemic renal injury was produced in male Sprague-Dawley rats weighing 150-200 g. Unilateral renal ischemia was induced by surgical clamping of the left renal artery for 50 min as previously described (35). After removal of the clamp to allow reperfusion for the indicated periods, rats were killed and kidneys were removed for analysis.…”