Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2005-8-11
pubmed:abstractText
Glomerular capillary hypertension is a final common pathway to glomerulosclerosis. Because podocyte loss is an early event in the development of glomerulosclerosis, it is logical that the deleterious effects of glomerular capillary hypertension involve podocyte injury. Yet, the mechanisms by which elevated intraglomerular pressure is translated into a maladaptive podocyte response remain poorly understood. Secreted protein acidic and rich in cysteine (SPARC) is a matricellular protein activated in various disease states of the podocyte and accelerates renal injury, as evidenced by the milder course of experimental diabetic nephropathy in SPARC-null mice compared with diabetic SPARC wild-type mice. Accordingly, we tested the hypothesis that mechanical strain activates SPARC in podocytes and thus is a putative mediator of podocyte injury in states of intraglomerular capillary hypertension. Conditionally immortalized mouse podocytes were subjected to 10% cyclical stretch while nonstretched cells served as controls. SPARC levels were measured in whole cell lysate and cell media. Immunostaining was performed for SPARC in an experimental model of glomerular capillary hypertension. Our results demonstrate cyclical stretch of podocytes markedly increased SPARC levels in cell lysate, through activation of p38, as well as secreted SPARC. Relevance was shown by demonstrating increased podocyte staining for SPARC in the uninephrectomized spontaneously hypertensive rat. In conclusion, we have made the novel observation that mechanical forces characteristic of states of glomerular capillary hypertension lead to increased levels of SPARC in podocytes. We speculate that the increase in SPARC may be maladaptive and lead to a progressive reduction in podocyte number, thus fueling the future development of glomerulosclerosis.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
1931-857X
pubmed:author
pubmed:issnType
Print
pubmed:volume
289
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
F577-84
pubmed:dateRevised
2011-4-28
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
Mechanical strain increases SPARC levels in podocytes: implications for glomerulosclerosis.
pubmed:affiliation
Division of Nephrology, Box 356521, Univ. of Washington School of Medicine, Seattle, WA 98195, USA. rdrvsula@u.washington.edu
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural