Evidence that a circulating factor is responsible for proteinuria in FSGS includes early recurrence of proteinuria in renal allografts, favorable clinical responses to plasmapheresis and immunoadsorption therapy, and our observation that plasma from FSGS patients increases glomerular albumin permeability (Palb) following in vitro incubation of isolated glomeruli to serum or plasma of certain FSGS patients. We have defined activity in this assay by the Palb of isolated glomeruli after incubation under standard conditions as """"""""FS activity"""""""". We have shown that FS activity of specimens obtained prior to transplantation predicts recurrence of proteinuria and later allograft loss. FS activity is diminished by plasmapheresis and a protein fraction of plasmapheresis fluid carries this activity. Intravenous injection of fractions derived from FSGS patients' plasma and carrying FS activity causes transient proteinuria in rats. FS activity of plasma or its fractions is concentration dependent. During purification, relative activity is increased by more than 33,000 fold compared to plasmapheresis fluid and the yield is more than 80 percent. The active component or """"""""FSGS factor"""""""" is a protein, as evidenced by its properties of insolubility in organic solvents, heat-lability, and protease sensitivity. It is anionic at physiologic pH, and in the most highly enriched fractions, has an apparent molecular size of 30-50 kD. We have used the high affinity of the factor to certain carbohydrates to design a simplified protocol for its enrichment. In the proposed studies, we will purify the FSGS factor from plasma of FSGS patients to homogeneity and will determine its amino acid sequence and carbohydrate composition. Techniques to be employed to further purify the material include affinity chromatography, chromatofocusing, size exclusion chromatography, ion exchange chromatography, isoelectric focusing and affinity chromatography using monoclonal antibodies. We will compare the FSGS factor to known proteins and glycoproteins to determine whether it is a previously described for a novel mediator. We will use monoclonal antibodies to develop an immunoassay for further studies of human FSGS. Application of this information will permit early identification of patients with the most aggressive forms of the disease, and, eventually, to design specific treatment for FSGS in native kidneys and renal allografts.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK043752-06
Application #
2905448
Study Section
Pathology A Study Section (PTHA)
Project Start
1993-12-15
Project End
2001-06-30
Budget Start
1999-07-01
Budget End
2000-06-30
Support Year
6
Fiscal Year
1999
Total Cost
Indirect Cost
Name
Medical College of Wisconsin
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
073134603
City
Milwaukee
State
WI
Country
United States
Zip Code
53226
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
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
Charba, Deane S; Wiggins, Roger C; Goyal, Meera et al. (2009) Antibodies to protein tyrosine phosphatase receptor type O (PTPro) increase glomerular albumin permeability (P(alb)). Am J Physiol Renal Physiol 297:F138-44
Aggarwal, Nidhi; Batwara, Ruchika; McCarthy, Ellen T et al. (2007) Serum permeability activity in steroid-resistant minimal change nephrotic syndrome is abolished by treatment of Hodgkin disease. Am J Kidney Dis 50:826-9
Sharma, Mukut; McCarthy, Ellen T; Sharma, Ram et al. (2006) Arachidonic acid metabolites mediate the radiation-induced increase in glomerular albumin permeability. Exp Biol Med (Maywood) 231:99-106
Gohh, R Y; Yango, A F; Morrissey, P E et al. (2005) Preemptive plasmapheresis and recurrence of FSGS in high-risk renal transplant recipients. Am J Transplant 5:2907-12
Trachtman, Howard; Greenbaum, Laurence A; McCarthy, Ellen T et al. (2004) Glomerular permeability activity: prevalence and prognostic value in pediatric patients with idiopathic nephrotic syndrome. Am J Kidney Dis 44:604-10
Sharma, Mukut; Sharma, Ram; McCarthy, Ellen T et al. (2004) The focal segmental glomerulosclerosis permeability factor: biochemical characteristics and biological effects. Exp Biol Med (Maywood) 229:85-98
Cattran, Daniel; Neogi, Tuhina; Sharma, Ram et al. (2003) Serial estimates of serum permeability activity and clinical correlates in patients with native kidney focal segmental glomerulosclerosis. J Am Soc Nephrol 14:448-53
Savin, Virginia J; McCarthy, Ellen T; Sharma, Mukut (2003) Permeability factors in focal segmental glomerulosclerosis. Semin Nephrol 23:147-60

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