Universität zu Köln

Nie, Mingzhu, Bal, Manjot S., Yang, Zhufeng, Liu, Jie, Rivera, Carolina, Wenzel, Andrea, Beck, Bodo B., Sakhaee, Khashayar, Marciano, Denise K. and Wolf, Matthias T. F. (2016). Mucin-1 Increases Renal TRPV5 Activity In Vitro, and Urinary Level Associates with Calcium Nephrolithiasis in Patients. J. Am. Soc. Nephrol., 27 (11). S. 3447 - 3459. WASHINGTON: AMER SOC NEPHROLOGY. ISSN 1533-3450

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Abstract

Hypercalciuria is a major risk factor for nephrolithiasis. We previously reported that Uromodulin (UMOD) protects against nephrolithiasis by upregulating the renal calcium channel TRPV5. This channel is crucial for calcium reabsorption in the distal convoluted tubule (DCT). Recently, mutations in the gene encoding Mucin-1 (MUC1) were found to cause autosomal dominant tubulointerstitial kidney disease, the same disease caused by UMOD mutations. Because of the similarities between UMOD and MUC1 regarding associated disease phenotype, protein structure, and function as a cellular barrier, we examined whether urinary MUC1 also enhances TRPV5 channel activity and protects against nephrolithiasis. We established a semiquantitative assay for detecting MUC1 in human urine and found that, compared with controls (n=12), patients (n=12) with hypercalciuric nephrolithiasis had significantly decreased levels of urinary MUC1. Immunofluorescence showed MUC1 in the thick ascending limb, DCT, and collecting duct. Applying whole cell patch-clamp recording of HEK cells, we found that wild-type but not disease mutant MUC1 increased TRPV5 activity by impairing dynamin-2- and caveolin-1-mediated endocytosis of TRPV5. Coimmunoprecipitation confirmed a physical interaction between TRPV5 and MUC1. However, MUC1 did not increase the activity of N-glycan-deficient TRPV5. MUC1 is characterized by variable number tandem repeats (VNTRs) that bind the lectin galectin-3; galectin-3 siRNA but not galectin-1 siRNA prevented MUC1-induced upregulation of TRPV5 activity. Additionally, MUC1 lacking VNTRs did not increase TRPV5 activity. Our results suggest that MUC1 forms a lattice with the N-glycan of TRPV5 via galectin-3, which impairs TRPV5 endocytosis and increases urinary calcium reabsorption.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Nie, Mingzhu UNSPECIFIED UNSPECIFIED UNSPECIFIED Bal, Manjot S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Yang, Zhufeng UNSPECIFIED UNSPECIFIED UNSPECIFIED Liu, Jie UNSPECIFIED UNSPECIFIED UNSPECIFIED Rivera, Carolina UNSPECIFIED UNSPECIFIED UNSPECIFIED Wenzel, Andrea UNSPECIFIED UNSPECIFIED UNSPECIFIED Beck, Bodo B. UNSPECIFIED UNSPECIFIED UNSPECIFIED Sakhaee, Khashayar UNSPECIFIED UNSPECIFIED UNSPECIFIED Marciano, Denise K. UNSPECIFIED UNSPECIFIED UNSPECIFIED Wolf, Matthias T. F. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-257296
DOI:	10.1681/ASN.2015101100
Journal or Publication Title:	J. Am. Soc. Nephrol.
Volume:	27
Number:	11
Page Range:	S. 3447 - 3459
Date:	2016
Publisher:	AMER SOC NEPHROLOGY
Place of Publication:	WASHINGTON
ISSN:	1533-3450
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language TAMM-HORSFALL PROTEIN; CELL-SURFACE; KIDNEY-DISEASE; MUC1 MUCIN; MEDIATED ENDOCYTOSIS; TUMOR PROGRESSION; CHANNEL TRPV5; EXPRESSION; CARCINOMA; CANCER Multiple languages Urology & Nephrology Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/25729