Focal segmental glomerulosclerosis (FSGS) and minimal change disease (MCD) are the most common causes of idiopathic nephrotic syndrome in humans. Their etiologies are unknown and treatment is empirical, consisting of drugs such as corticosteroids and cyclosporine A (CSA). Products of cytochrome P450 (CYP450) arachidonic acid metabolism are increasingly recognized as playing important roles in renal physiology. The effect of CYP450 4A products on glomerular function has not been described. In preliminary studies, we have shown that exogenous 20- hydroxyeicosatetraenoic acid (20-HETE), the major product of CYP450 4A, prevents increased in vitro albumin permeability (P(alb)) in models of glomerular injury, and that glomeruli from rats treated with agents known to induce renal CYP450 4A expression are also protected from increased P(alb). We hypothesize that 20-HETE, an arachidonic acid metabolite of CYP450 4A, protects the glomerular filtration barrier from noninflammatory injury such as that responsible for FSGS and MCD. We will induce glomerular injury using the FSGS factor, a substance from the plasma of patients with FSGS, or puromycin aminonucleoside (PAN), a glomerular epithelial cell toxin. We will also study rats in which expression and/or activity of CYP450 4A has been altered by pharmacological agents (CSA, corticosteroid or fibrate) or genetic manipulations. We will pursue the following Specific Aims: 1) To determine expression of CYP450 4A in models of glomerular injury; 2) To determine activity of CYP450 4A in models of glomerular injury; 3) To document the effect of 20-HETE on glomerular protein permeability in models of injury; 4) To define the effect of pharmacological agents on glomerular CYP450 4A expression and activity; 5) To define the effect of pharmacological agents on glomerular protein permeability in models of injury. We will also perform initial studies on mechanism of protection. We will employ established techniques of Western blotting, real-time PCK, liquid chromatography/mass spectrometry (LC/MS), micropuncture and urinary clearance. We will also use unique methods, reagents and experimental animals. These include measurement of P(alb) of isolated glomerular, observation of glomerular albumin filtration using intravital two-photon microscopy, use of unique analogs and blockers of 20-HETE and of congenic rats with varying expression of CYP450 4A. Results of the proposed studies will provide insights into glomerular responses to injury and the mechanisms by which therapeutic agents provide glomerular protection. These insights will permit development of new therapies to treat human proteinuric renal diseases and arrest the progression of glomerular injury.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
1R01DK064969-01A2
Application #
6870441
Study Section
Pathobiology of Kidney Disease Study Section (PBKD)
Program Officer
Moxey-Mims, Marva M
Project Start
2005-03-01
Project End
2010-02-28
Budget Start
2005-03-01
Budget End
2006-02-28
Support Year
1
Fiscal Year
2005
Total Cost
$328,496
Indirect Cost
Name
Medical College of Wisconsin
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
937639060
City
Milwaukee
State
WI
Country
United States
Zip Code
53226
Srivastava, Tarak; Hariharan, Sundaram; Alon, Uri S et al. (2018) Hyperfiltration-mediated Injury in the Remaining Kidney of a Transplant Donor. Transplantation 102:1624-1635
Sharma, Mukut; Sharma, Ram; McCarthy, Ellen T et al. (2017) Hyperfiltration-associated biomechanical forces in glomerular injury and response: Potential role for eicosanoids. Prostaglandins Other Lipid Mediat 132:59-68
Srivastava, Tarak; Thiagarajan, Ganesh; Alon, Uri S et al. (2017) Role of biomechanical forces in hyperfiltration-mediated glomerular injury in congenital anomalies of the kidney and urinary tract. Nephrol Dial Transplant 32:759-765
Pudur, Sudhindra; Srivastava, Tarak; Sharma, Mukut et al. (2016) Serum glomerular albumin permeability activity: association with rapid progression to end-stage renal disease in focal segmental glomerulosclerosis. Springerplus 5:432
Sharma, Mukut; Zhou, Jianping; Gauchat, Jean-François et al. (2015) Janus kinase 2/signal transducer and activator of transcription 3 inhibitors attenuate the effect of cardiotrophin-like cytokine factor 1 and human focal segmental glomerulosclerosis serum on glomerular filtration barrier. Transl Res 166:384-98
Savin, Virginia J; Sharma, Mukut; Zhou, Jianping et al. (2015) Renal and Hematological Effects of CLCF-1, a B-Cell-Stimulating Cytokine of the IL-6 Family. J Immunol Res 2015:714964
McCarthy, Ellen T; Zhou, Jianping; Eckert, Ryan et al. (2015) Ethanol at low concentrations protects glomerular podocytes through alcohol dehydrogenase and 20-HETE. Prostaglandins Other Lipid Mediat 116-117:88-98
Srivastava, Tarak; Celsi, Gianni E; Sharma, Mukut et al. (2014) Fluid flow shear stress over podocytes is increased in the solitary kidney. Nephrol Dial Transplant 29:65-72
McCarthy, Ellen T; Sharma, Mukut; Savin, Virginia J (2010) Circulating permeability factors in idiopathic nephrotic syndrome and focal segmental glomerulosclerosis. Clin J Am Soc Nephrol 5:2115-21
Sharma, Mukut; McCarthy, Ellen T; Reddy, D Sudarshan et al. (2009) 8,9-Epoxyeicosatrienoic acid protects the glomerular filtration barrier. Prostaglandins Other Lipid Mediat 89:43-51

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