Medicine and Health Sciences Commons^™

Mechanotransduction Signaling In Podocytes From Fluid Flow Shear Stress., Tarak Srivastava, Hongying Dai, Daniel P. Heruth, Uri S. Alon, Robert E. Garola, Jianping Zhou, R Scott Duncan, Ashraf El-Meanawy, Ellen T. Mccarthy, Ram Sharma, Mark L. Johnson, Virginia J. Savin, Mukut Sharma

Manuscripts, Articles, Book Chapters and Other Papers

Recently, we and others have found that hyperfiltration-associated increase in biomechanical forces, namely, tensile stress and fluid flow shear stress (FFSS), can directly and distinctly alter podocyte structure and function. The ultrafiltrate flow over the major processes and cell body generates FFSS to podocytes. Our previous work suggests that the cyclooxygenase-2 (COX-2)-PGE2-PGE2 receptor 2 (EP2) axis plays an important role in mechanoperception of FFSS in podocytes. To address mechanotransduction of the perceived stimulus through EP2, cultured podocytes were exposed to FFSS (2 dyn/cm2) for 2 h. Total RNA from cells at the end of FFSS treatment, 2-h post-FFSS, and 24-h …

Hyperfiltration-Associated Biomechanical Forces In Glomerular Injury And Response: Potential Role For Eicosanoids., Mukut Sharma, Ram Sharma, Ellen T. Mccarthy, Virginia J. Savin, Tarak Srivastava

Manuscripts, Articles, Book Chapters and Other Papers

Hyperfiltration is a well-known risk factor in progressive loss of renal function in chronic kidney disease (CKD) secondary to various diseases. A reduced number of functional nephrons due to congenital or acquired cause(s) results in hyperfiltration in the remnant kidney. Hyperfiltration-associated increase in biomechanical forces, namely pressure-induced tensile stress and fluid flow-induced shear stress (FFSS) determine cellular injury and response. We believe the current treatment of CKD yields limited success because it largely attenuates pressure-induced tensile stress changes but not the effect of FFSS on podocytes. Studies on glomerular podocytes, tubular epithelial cells and bone osteocytes provide evidence for a …

Biochemical And Biophysical Methods For Analysis Of Poly(Adp-Ribose) Polymerase 1 And Its Interactions With Chromatin., Maggie H. Chassé, Uma M. Muthurajan, Nicholas J. Clark, Michael A. Kramer, Srinivas Chakravarthy, Thomas Irving, Karolin Luger

Manuscripts, Articles, Book Chapters and Other Papers

Poly (ADP-Ribose) Polymerase I (PARP-1) is a first responder to DNA damage and participates in the regulation of gene expression. The interaction of PARP-1 with chromatin and DNA is complex and involves at least two different modes of interaction. In its enzymatically inactive state, PARP-1 binds native chromatin with similar affinity as it binds free DNA ends. Automodification of PARP-1 affects interaction with chromatin and DNA to different extents. Here we describe a series of biochemical and biophysical techniques to quantify and dissect the different binding modes of PARP-1 with its various substrates. The techniques listed here allow for high …

Fluid Flow Shear Stress Over Podocytes Is Increased In The Solitary Kidney., Tarak Srivastava, Gianni E. Celsi, Mukut Sharma, Hongying Dai, Ellen T. Mccarthy, Melanie Ruiz, Patricia A. Cudmore, Uri S. Alon, Ram Sharma, Virginia A. Savin

Manuscripts, Articles, Book Chapters and Other Papers

BACKGROUND: Glomerular hyperfiltration is emerging as the key risk factor for progression of chronic kidney disease (CKD). Podocytes are exposed to fluid flow shear stress (FFSS) caused by the flow of ultrafiltrate within Bowman's space. The mechanism of hyperfiltration-induced podocyte injury is not clear. We postulated that glomerular hyperfiltration in solitary kidney increases FFSS over podocytes.

METHODS: Infant Sprague-Dawley rats at 5 days of age and C57BL/6J 14-week-old adult mice underwent unilateral nephrectomy. Micropuncture and morphological studies were then performed on 20- and 60-day-old rats. FFSS over podocytes in uninephrectomized rats and mice was calculated using the recently published equation …