Deletion of scavenger receptor A protects mice from progressive nephropathy independent of lipid control during diet-induced hyperlipidemia

Kidney Int. 2012 May;81(10):1002-1014. doi: 10.1038/ki.2011.457. Epub 2012 Feb 29.

Abstract

Scavenger receptor A (SR-A) is a key transmembrane receptor in the endocytosis of lipids and contributes to the pathogenesis of atherosclerosis. To assess its role in hyperlipidemic chronic kidney disease, wild-type and SR-A-deficient (knockout) mice underwent uninephrectomy followed by either normal or high-fat diet. After 16 weeks of diet intervention, hyperlipidemic wild-type mice presented characteristic features of progressive nephropathy: albuminuria, renal fibrosis, and overexpression of transforming growth factor (TGF)-β1/Smad. These changes were markedly diminished in hyperlipidemic knockout mice and attributed to reduced renal lipid retention, oxidative stress, and CD11c(+) cell infiltration. In vitro, overexpression of SR-A augmented monocyte chemoattractant protein-1 release and TGF-β1/Smad activation in HK-2 cells exposed to oxidized low-density lipoprotein. SR-A knockdown prevented lipid-induced cell injury. Moreover, wild-type to knockout bone marrow transplantation resulted in renal fibrosis in uninephrectomized mice following 16 weeks of the high-fat diet. In contrast, knockout to wild-type bone marrow transplantation led to markedly reduced albuminuria, CD11c(+) cell infiltration, and renal fibrosis compared to wild-type to SR-A knockout or wild-type to wild-type bone marrow transplanted mice, without difference in plasma lipid levels. Thus, SR-A on circulating leukocytes rather than resident renal cells predominantly mediates lipid-induced kidney injury.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Albuminuria / etiology
  • Albuminuria / metabolism
  • Albuminuria / prevention & control
  • Animals
  • Bone Marrow Transplantation
  • CD11c Antigen / metabolism
  • Cell Line
  • Chemokine CCL2 / metabolism
  • Chronic Disease
  • Dietary Fats / blood
  • Dietary Fats / metabolism*
  • Disease Models, Animal
  • Disease Progression
  • Fibrosis
  • Hyperlipidemias / complications*
  • Hyperlipidemias / etiology
  • Kidney / metabolism*
  • Kidney / pathology
  • Kidney Diseases / etiology
  • Kidney Diseases / genetics
  • Kidney Diseases / metabolism
  • Kidney Diseases / pathology
  • Kidney Diseases / prevention & control*
  • Leukocytes / metabolism*
  • Male
  • Mice
  • Mice, Knockout
  • Nephrectomy
  • Oxidative Stress
  • RNA Interference
  • Scavenger Receptors, Class A / deficiency*
  • Scavenger Receptors, Class A / genetics
  • Scavenger Receptors, Class A / metabolism
  • Signal Transduction
  • Smad Proteins / metabolism
  • Superoxide Dismutase / genetics
  • Superoxide Dismutase / metabolism
  • Time Factors
  • Transfection
  • Transforming Growth Factor beta1 / metabolism

Substances

  • CCL2 protein, human
  • CD11c Antigen
  • Chemokine CCL2
  • Dietary Fats
  • MSR1 protein, human
  • Msr1 protein, mouse
  • Scavenger Receptors, Class A
  • Smad Proteins
  • TGFB1 protein, human
  • Tgfb1 protein, mouse
  • Transforming Growth Factor beta1
  • Superoxide Dismutase