Kidney Week

Abstract: SA-PO080

Hdac8 Knockout Results in Amelioration of AKI in Zebrafish

Session Information

• AKI: Mechanisms - Primary Injury and Repair - II
  November 09, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Acute Kidney Injury

• 103 AKI: Mechanisms

Authors

• Han, Hwa In, University of Pittsburgh, Pittsburgh, Pennsylvania, United States

Hwa In Han,

• Crunk, Amanda, University of Pittsburgh, Pittsburgh, Pennsylvania, United States

Amanda Crunk,

• Crana, Christine M., UPMC, Pittsburgh, Pennsylvania, United States

Christine M. Crana,

• McDaniels, Michael D., University of Pittsburgh, Pittsburgh, Pennsylvania, United States

Michael D. McDaniels,

• Hukriede, Neil A., University of Pittsburgh, Pittsburgh, Pennsylvania, United States

Neil A. Hukriede,

Background

Despite the prevalence of AKI, the need for therapeutics is currently unmet. One candidate for a small molecule therapeutic is 4-(phenylthio) butanoic acid (PTBA), which had previously shown increased RTEC productive repair and functional recovery by enhancing dedifferentiation and decreasing injury in both murine and zebrafish models of AKI. Here, we show that histone deacetylase 8 (HDAC8) is potential target of PTBA. HDAC8 is known to interact with cell cycle regulators, such as SMC3 and p53, to acetylate and modulate cell cycle activity. We further investigate the role of Hdac8 in affecting the cell cycle using a larval zebrafish model of AKI.

Methods

Cellular thermal shift assay (CETSA) was used to evaluate the target engagement of PTBA with HDACs. hdac8^sa14948/-and hdac8 ^sa14948/+mutant zebrafish were injected with gentamicin to induce AKI and observed for post-injury survival from 1-7dpi. Cells harvested from whole larvae were stained with propidium iodide and analyzed with flow cytometry for variation in the cell cycle phase. Using cell cycle specific antibodies, EdU and pH3, larval pronephros were stained for S and G2/M phases at various timepoints following AKI.

Results

PTBA was shown to stabilize HDAC8 at higher temperatures compared to control, consistent with PTBA binding to HDAC8. hdac8 ^sa14948/- fish showed significantly increased survival when compared with wildtype and hdac8 ^sa14948/+. Analysis of whole larvae cell cycle showed increased G1/S population with injury at 1dpi. Immunohistochemistry showed increased EdU during an early injury timepoint (1dpi) while showing delayed G2/M entrance in a later injury timepoint (4dpi).

Conclusion

Absence of Hdac8 in larval zebrafish model of AKI improved survival. The survival correlated with increased G1/S cell cycle phase during earlier timepoints of injury, as well as delayed entrance to G2/M. Here, we demonstrate the role of Hdac8 in increasing repair by delaying proliferation after injury. Furthermore, we have identified PTBA as an HDAC8 inhibitor. Taken together these data suggest a potential mechanism to induce productive repair after an AKI event.

Funding

• NIDDK Support