Mohammad Al-bataineh, DVM, MS, PhD Post-doctoral Scholar Rebecca Hughey Laboratory Renal-Electrolyte Division The Protective Role of MUC1/β-catenin Pathway in Acute Kidney Injury ​

N C Autocatalytic cleavage within SEA module membrane Near perfect tandem repeats N-linked glycans O-linked glycans MUC1 is a transmembrane glycoprotein with an extracellular mucin-like domain that yields protection from pathogens MUC1 overexpression in tumors is a bad prognosis for the patient MUC1 expression in tumor cell lines:  Pro-survival and anti-apoptotic activities  Modulates transcriptional activities after nuclear targeting Highly conserved across species exhibits multiple sites for protein docking and phosphorylation involved in signal transduction (e.g., HIF1 , GSK3β, β-catenin) MUC1 in the kidney:  Apical expression on all polarized epithelia during development  Found in the DCT and CD in adult kidneys  Found in the PT during development and after injury

Muc1 protein - immunblotting Muc1 is induced during ischemia-reperfusion injury (IRI) C57BL/6 MICE 19 min ischemia N=3-5 mice T= 0-72 h Kidney cortex Muc1 is targeted to the nucleus during IRI (4 h recovery)

Kidney function and morphology are protected by Muc1 during IRI C57BL/6Muc1 KO t=0congested n=3 t=24 h5, 5, 5, 55, 5, 5n=3-4 t=72 hrecoveringcalcificationn=5-6 Wu et al., J. Clin. Invest. 117:2847–2859 (2007)

Muc1 enhances the hypoxia-inducible factor-1 (HIF-1) protective pathway during IRI 19 min ischemia t=4 h lactate dehydrogenase A, enolase, pyruvate kinase M2, and pyruvate dehydrogenase kinase 1

The HIF-1 protective pathway is enhanced by the nuclear targeting of Muc1 in a mouse kidney model of IRI

How the  -catenin protective pathway is regulated in kidneys under metabolic stress conditions like IRI? Kidney International (2012) 82, 537–547 Kidney function Kidney morphology

Cancer Res 2005; 65: (22). November 15, 2005 In cancer cell lines:

Hypothesis Muc1 is protective in a mouse kidney model of IRI also through stabilization and transactivation of the  -catenin protective pathway.

Induction of  -catenin during IRI is absent in Muc1 KO mice  -catenin co-IP with MUC1 in Human kidney proximal tubule HK-2 cells

Nuclear targeting of  -catenin during IRI is absent in Muc1 KO mice

Does MUC1 modulate  -catenin activities during IRI ?

Activation of TCF4 during IRI is significantly reduced in Muc1 KO mice

Activation of Akt is significantly reduced during IRI in the absence of Muc1

Induction of survivin during IRI is absent in Muc1 KO mice

SUMMARY Muc1 stabilizes  -catenin, enhances its nuclear translocation, and augments expression of its downstream targets in a mouse model of AKI. Muc1 protects the kidney during IRI through transactivation of the  -catenin protective pathway, as evidenced by: activation of pro-survival factors like activated Akt, survivin, TCF4, and its target cyclin D1 repression of pro-apoptotic factors; such as p53, and cleaved caspase 3 (consistent with decreased apoptosis) What is the specific role and mechanism of  -catenin signaling during kidney injury, recovery and repair? Future studies

University of Pittsburgh Renal-Electrolyte Division Rebecca Hughey Carol L Kinlough (Truschel) Paul Poland Núria M Pastor-Soler Department of Pathology Sheldon I Bastacky Satdarshan (Paul) Monga Sucha Singh Pediatrics Jackie Ho Funding NIH R01 NRSA (F32) NIDDK O’Brien Kidney Center (P30) Mayo Clinic, Scottsdale, AZ Sandra J Gendler and Cathy S Madsen Indiana University, Indianapolis, IN Timothy A Sutton and Henry E Mang Vanderbilt University, Nashville, TN Volker H Haase and Hanako Kobayashi ACKNOWLEDGMENTS