Mutations in TRPC6, a nonspecific cation channel, have been found to lead to hereditary forms of focal segmental glomerulosclerosis. This project aims to define the role of TRPC6 in normal and abnormal glomerular function, with the goal of identifying the critical signaling pathways influenced by TRPC6. To this end, the candidate will: 1) characterize the mechanism whereby a subset of disease-associated mutations enhance TRPC6 channel activity;2) assess the relative importance of abnormal TRPC6 function within various cell types within the glomerulus;and 3) establish the potential role of the NFAT transcription factor family as a target of TRPC6 signaling in the glomerulus. The candidate has past experience in a host of basic cell biology methods. In addition, during his post-doctoral fellowship training in Dr. Pollak's lab he has begun to develop an understanding of the techniques and experimental design required for studying channel biology, transcriptional activation, and for developing urine models of kidney disease. He has generated considerable preliminary data pertinent to the project. During his proposed project period, Dr. Schlondorff will be able to master several new techniques, including methods of intracellular calcium imaging, Cre-Lox transgenic animal generation, analysis of murine renal pathology, immunohistochemistry, and microarray gene expression technology. In addition to skilled members of the Pollak laboratory, Dr. Schlondorff has garnered the cooperation of several accomplished experts at the Harvard Medical School to assist him in these areas of development.

Public Health Relevance

Focal segmental glomerular sclerosis (FSGS) is a kidney lesion seen in a number of disease states, contributes significantly to the population of patients with end-stage renal disease requiring dialysis or kidney transplantation, and currently lacks effective therapies. By gaining a better understanding of how genetic defects in an ion channel can lead to this disease, this project hopes to identify critical processes whose disruption lead to FSGS and kidney dysfunction in multiple forms of kidney disease. Our goal is that these insights will identify novel potential targets against which to develop therapeutic interventions.

National Institute of Health (NIH)
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Clinical Investigator Award (CIA) (K08)
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Diabetes, Endocrinology and Metabolic Diseases B Subcommittee (DDK)
Program Officer
Rankin, Tracy L
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Beth Israel Deaconess Medical Center
United States
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Barua, Moumita; Shieh, Eric; Schlondorff, Johannes et al. (2014) Exome sequencing and in vitro studies identified podocalyxin as a candidate gene for focal and segmental glomerulosclerosis. Kidney Int 85:124-33
Chiluiza, David; Krishna, Sneha; Schumacher, Valérie A et al. (2013) Gain-of-function mutations in transient receptor potential C6 (TRPC6) activate extracellular signal-regulated kinases 1/2 (ERK1/2). J Biol Chem 288:18407-20
Sun, Hua; Schlondorff, Johannes; Higgs, Henry N et al. (2013) Inverted formin 2 regulates actin dynamics by antagonizing Rho/diaphanous-related formin signaling. J Am Soc Nephrol 24:917-29
Carrasquillo, Robert; Tian, Dequan; Krishna, Sneha et al. (2012) SNF8, a member of the ESCRT-II complex, interacts with TRPC6 and enhances its channel activity. BMC Cell Biol 13:33
Cheong, Hae Il; Kang, Hee Gyung; Schlondorff, Johannes (2012) GLCCI1 single nucleotide polymorphisms in pediatric nephrotic syndrome. Pediatr Nephrol 27:1595-9
Sun, Hua; Schlondorff, Johannes S; Brown, Elizabeth J et al. (2011) Rho activation of mDia formins is modulated by an interaction with inverted formin 2 (INF2). Proc Natl Acad Sci U S A 108:2933-8
Brown, Elizabeth J; Schlöndorff, Johannes S; Becker, Daniel J et al. (2010) Mutations in the formin gene INF2 cause focal segmental glomerulosclerosis. Nat Genet 42:72-6
Tian, Dequan; Jacobo, Sarah M P; Billing, David et al. (2010) Antagonistic regulation of actin dynamics and cell motility by TRPC5 and TRPC6 channels. Sci Signal 3:ra77
Schlöndorff, Johannes; Del Camino, Donato; Carrasquillo, Robert et al. (2009) TRPC6 mutations associated with focal segmental glomerulosclerosis cause constitutive activation of NFAT-dependent transcription. Am J Physiol Cell Physiol 296:C558-69