# Mechanistic Underpinnings of Chronic Kidney Disease Initiated by Acute Cardiorenal Syndrome

> **NIH VA I01** · PORTLAND VA MEDICAL CENTER · 2020 · —

## Abstract

Acute cardiorenal syndrome imperils the survival of half of cardiac arrest survivors and that of many patients
with myocardial infarction or acute heart failure. Patients who survive have high risk of chronic kidney disease
(CKD). The hypothesis in this proposal is that cardiac arrest and cardiopulmonary resuscitation in the mouse
(CA/CPR) causes filtration and tubular endocytosis of cardiac LIM protein (CSRP3), a soluble inducer of renal
fibrosis, which initiates chronic kidney disease via Wingless (Wnt)-effector activation in renal tubular
epithelium. The objectives in this proposal are:
1) Establish whether a soluble factor explains the potent induction of CKD by CA/CPR , 2) Determine whether
tubular endocytosis of CSRP3 via the endocytic receptor megalin leads to renal fibrosis, and 3) Determine the
intracellular mechanism of fibrosis induction by CSRP3.
Aim 1 tests the hypothesis that CA/CPR potently induces CKD via a soluble factor from the heart. CA/CPR will
be performed in mice with deletion of cardiac CSRP3, and CSRP3 will be administered to mice with deletion of
cardiac CSRP3 to recapitulate the wild-type injury. Renal fibrosis glomerular filtration rate and urine protein will
be quantified. Aim 2 tests the hypothesis that functional endocytosis via the tubular epithelial receptor megalin
is required for development of CA/CPR-induced renal fibrosis. CA/CPR will be performed in mice with
conditional, proximal tubular-specific deletion of megalin (and littermate controls). 7 weeks later mice will be
tested for chronic kidney disease, quantifying fibrosis, glomerular filtration rate, and urine protein. Aim 3 tests
the hypothesis that CSRP3 translocates to the tubular epithelial cell nucleus and induces Wnt effector genes.
Tubular epithelial cells will be exposed to CSRP3, and a Wnt-effector reporter system and immunoblotting and
immunohistochemistry used to determine Wnt effector transcription, and localize CSRP3.
Methods: Murine CA/CPR will be employed in aim 1 and aim 2. Briefly, under isoflurane anesthesia, cardiac
arrest is induced with potassium chloride and resuscitated 8 min later with chest compressions and
epinephrine, analogous to resuscitation of cardiac arrest in humans. Preliminary data indicate that 7 weeks
after CA/CPR, there is robust induction of renal fibrosis and reduction in glomerular filtration rate. Aim 1
employs mice with inducible deletion of cardiac CSRP3. Aim 2 will use 2 strains of mice with deletion of
proximal tubular megalin, one with mosaic and lifelong deletion, and the second with inducible, complete
deletion of megalin. CA/CPR and recombinant CSRP3 administration will be employed in these two strains to
test the involvement of megalin. Aim 3 will be conducted in vitro, using immortalized human tubular epithelial
cells (the HK2 line). Cells will be transfected with a Wnt reporter system (TOPFlash) which yields fluorescence
proportional to transcription of Wnt effector genes. TOPFlash will be used to test t...

## Key facts

- **NIH application ID:** 9892583
- **Project number:** 1I01BX004288-01A2
- **Recipient organization:** PORTLAND VA MEDICAL CENTER
- **Principal Investigator:** Michael P Hutchens
- **Activity code:** I01 (R01, R21, SBIR, etc.)
- **Funding institute:** VA
- **Fiscal year:** 2020
- **Award amount:** —
- **Award type:** 1
- **Project period:** 2020-01-01 → 2023-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9892583

## Citation

> US National Institutes of Health, RePORTER application 9892583, Mechanistic Underpinnings of Chronic Kidney Disease Initiated by Acute Cardiorenal Syndrome (1I01BX004288-01A2). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9892583. Licensed CC0.

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