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Role of claudin-2 in Calcium Homeostasis and Kidney Stone Disease

Award Number: R01DK115727
ORGANIZATION: NATIONAL INSTITUTE OF DIABETES & DIGESTIVE & KIDNEY DISEASES
OPDIV: NIH
AWARD CLASS: DISCRETIONARY
AWARD ACTIVITY TYPE: SCIENTIFIC/HEALTH RESEARCH (INCLUDES SURVEYS)
PERIOD OF PERFORMANCE START DATE: 09/18/2019
PERIOD OF PERFORMANCE END DATE: 08/31/2025

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Role of claudin-2 in Calcium Homeostasis and Kidney Stone Disease - PROJECT SUMMARY/ABSTRACT Kidney stones affect 9% of the population and idiopathic hypercalciuria is the major pathogenic risk factor. Our long-term goal is to elucidate the pathogenesis of idiopathic hypercalciuria and develop novel therapies. The renal proximal tubule reabsorbs 70% of filtered calcium, which is believed to occur via the paracellular pathway. Claudin-2 is a paracellular cation channel that is expressed in the proximal renal tubule and in intestinal epithelium. In preliminary studies, we show that claudin-2 knockout mice have renal and absorptive hypercalciuria, leading to severe papillary nephrocalcinosis. Moreover, we find that claudin-2 gene variants are associated with kidney stone disease in humans. We hypothesize that claudin-2 mediates calcium reabsorption in the proximal tubule and calcium secretion in the colon. Loss of claudin-2 increases calcium delivery to the loop of Henle, and predisposes to inner medullary calcium deposition and hence kidney stone disease. The specific aims to test this hypothesis are: (1) Test whether claudin-2 mediates paracellular calcium reabsorption in the renal proximal tubule. We will use tubule micropuncture of claudin-2 global knockout mice, determine the contribution of the proximal tubule with kidney-specific conditional knockout mice, test the role of claudin-2 in the hypocalciuric effect of thiazides, and explore the effect of sex. (2) Test whether claudin-2 mediates intestinal secretion of calcium. We will generate intestine-specific claudin-2 knockout mice and perform tracer flux assays in everted intestinal sacs and Ussing chamber preparations. (3) Test whether human claudin-2 gene variants and protein expression are associated with urine calcium and kidney stones. We will conduct a gene association study in 3 U.S. population-based cohorts to test the association of claudin-2 gene polymorphisms with a history of kidney stones and calcium excretion. In a separate cohort of kidney stone formers and matched normal volunteers, we will test the association of claudin-2 protein abundance in urinary exosomes with hypercalciuric kidney stone disease.


Issue Date FY	Funding FY	Legal Entity Name	Legal Entity Address	Legal Entity City	Legal Entity State	Legal Entity Zip Code	Legal Entity COUNTY	Legal Entity COUNTRY	Assistance Listing	Award Code	Budget Year	Action Date	Action Type	Action Amount

Issue Date FY: 2026 ( Subtotal = $0 )
2026	2023	UNIVERSITY OF KANSAS MEDICAL CENTER RESEARCH INSTITUTE, INC.	3901 RAINBOW BLVD	KANSAS CITY	KS	66160	WYANDOTTE	USA	Diabetes, Digestive, and Kidney Diseases Extramural Research	000	5	12/15/2025	NON-COMPETING CONTINUATION	$0
														Subtotal = $0

Issue Date FY: 2023 ( Subtotal = $310,766 )
2023	2023	UNIVERSITY OF KANSAS MEDICAL CENTER RESEARCH INSTITUTE, INC.	3901 RAINBOW BLVD	KANSAS CITY	KS	66160	WYANDOTTE	USA	Diabetes, Digestive, and Kidney Diseases Extramural Research	000	5	8/8/2023	NON-COMPETING CONTINUATION	$310,766
														Subtotal = $310,766

Issue Date FY: 2022 ( Subtotal = $310,766 )
2022	2022	UNIVERSITY OF KANSAS MEDICAL CENTER RESEARCH INSTITUTE, INC.	4330 SHAWNEE MISSION PKWY	SHAWNEE MISSION	KS	66205	JOHNSON	USA	Diabetes, Digestive, and Kidney Diseases Extramural Research	000	4	8/25/2022	NON-COMPETING CONTINUATION	$310,766
														Subtotal = $310,766

Issue Date FY: 2021 ( Subtotal = $310,766 )
2021	2021	UNIVERSITY OF KANSAS MEDICAL CENTER RESEARCH INSTITUTE, INC.	4330 SHAWNEE MISSION PKWY	SHAWNEE MISSION	KS	66205	JOHNSON	USA	Diabetes, Digestive, and Kidney Diseases Extramural Research	000	3	8/27/2021	NON-COMPETING CONTINUATION	$310,766
														Subtotal = $310,766

Issue Date FY: 2020 ( Subtotal = $437,080 )
2020	2020	UNIVERSITY OF KANSAS MEDICAL CENTER RESEARCH INSTITUTE, INC.	4330 SHAWNEE MISSION PKWY	SHAWNEE MISSION	KS	66205	JOHNSON	USA	Diabetes, Digestive, and Kidney Diseases Extramural Research	000	2	8/13/2020	NON-COMPETING CONTINUATION	$437,080
														Subtotal = $437,080

Issue Date FY: 2019 ( Subtotal = $476,830 )
2019	2019	UNIVERSITY OF KANSAS MEDICAL CENTER RESEARCH INSTITUTE, INC.	4330 SHAWNEE MISSION PKWY	SHAWNEE MISSION	KS	66205	JOHNSON	USA	Diabetes, Digestive, and Kidney Diseases Extramural Research	000	1	9/19/2019	NEW	$476,830
														Subtotal = $476,830

Grand Total All Awards = $1,846,208

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Role of claudin-2 in Calcium Homeostasis and Kidney Stone Disease

Award Number: R01DK115727

ORGANIZATION: NATIONAL INSTITUTE OF DIABETES & DIGESTIVE & KIDNEY DISEASES

OPDIV: NIH

AWARD CLASS: DISCRETIONARY

AWARD ACTIVITY TYPE: SCIENTIFIC/HEALTH RESEARCH (INCLUDES SURVEYS)

PERIOD OF PERFORMANCE START DATE: 09/18/2019

PERIOD OF PERFORMANCE END DATE: 08/31/2025

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