Abstract: SA-PO775
Myocardiocyte Transcription Factor Cardiac LIM Protein (CSRP3) Mediates Renal Tubular Transcription
Session Information
- CKD: Mechanisms - III
November 09, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: CKD (Non-Dialysis)
- 2103 CKD (Non-Dialysis): Mechanisms
Authors
- Hutchens, Michael, Portland VA Medical Center, Portland, Oregon, United States
- Eiwaz, Mahaba B., Oregon Health & Science University, Portland, Oregon, United States
- Matsushita, Katsuyuki, Kyushu University Hospital, Kyushu, Japan
Background
Cardiac LIM Protein (CSRP3, molecular weight 21 kD), is released from the heart into the systemic circulation after myocardial injury; we recently identified it as an endocrine cardiorenal connector. We hypothesized that modeled release of CSRP3 would alter tubular epithelial cell transcription of renal fibrosis-related genes in vivo and in vitro.
Methods
Cardiac arrest was induced with potassium chloride, and terminated with cardiopulmonary resuscitation (CA/CPR, a model of cardiac injury leading to acute cardiorenal syndrome). CA/CPR or sham procedure was performed in male, 8-12 week old male mice (WT mice). Mice were killed 10h, 24h, 72h, or 7 days later and plasma CSRP3 quantified by ELISA. Recombinant CSRP3 (rCSRP3) was purchased and 1 µg injected intravenously to WT mice. Mice were killed and plasma CSRP3 quantified by ELISA. Curves were fit to model pharmacokinetics. Following injection, mice were perfusion-fixed; the right kidney was snap-frozen and prepared for mRNA measurements and the left paraffin-embedded for immunofluorescence. qPCR for lef1 and tgfb1 mRNA, and CSRP3 immunofluorescence were performed on kidney tissue. Human kidney cells were exposed to 1 µM rCSRP3 or vehicle in translational relevance studies.
Results
CA/CPR resulted greatly increased plasma CSRP3 (max 20.3±3.3 vs. 1.4±0.2 in sham, ng/mL, p=0.04) and remained detectable in plasma at 7 days (5.6±1.6 ng/mL). The 7-day area-under the curve (AUC) was 65 ng/mL*day. The t1/2 for injected rCSRP3, was 86 minutes, and the AUC for a single 1µg dose was 15 ng/mL*days. Immunofluorescence demonstrated CSRP3 within tubular epithelial cell nuclei following injection. Renal tissue mRNA for transforming growth factor beta (tgfb1) was 1.7-(±0.28-fold) increased 6h after rCSRP3 injection, while lef1 mRNA was not regulated. In human tubular epithelial cells, 16h exposure to 1 µM CSRP3 upregulated lef1 mRNA 1.8±0.15-fold compared to vehicle control (p=0.02).
Conclusion
CSRP3, highly specific to cardiomyocytes, is released into the circulation after cardiac injury, and mediates renal transcription of fibrosis-related genes in vivo and in vitro. We postulate this cardiomyocyte transcription factor may play a role in AKI-CKD transition following acute cardiac illness such as cardiac arrest or myocardial infarction.
Funding
- Veterans Affairs Support