Kidney Week

Abstract: SA-PO110

Deficiency of Hedgehog Interacting Protein (Hhip) in Endothelial Cells Prevents Kidney Ischemia-Reperfusion-Mediated Renal Tubular Cell Senescence

Session Information

• AKI: Inflammation and Cell Cycle
  October 26, 2024 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Acute Kidney Injury

• 103 AKI: Mechanisms

Authors

• Pang, Yuchao, Centre de Recherche du Centre Hospitalier de l'Universite de Montreal, Montreal, Quebec, Canada

Yuchao Pang, MS, MSc

• Peng, Junzheng, Centre de Recherche du Centre Hospitalier de l'Universite de Montreal, Montreal, Quebec, Canada

Junzheng Peng, MD

• Zhao, Xin-Ping, Centre de Recherche du Centre Hospitalier de l'Universite de Montreal, Montreal, Quebec, Canada

Xin-Ping Zhao

• Chang, Shiao-Ying, Centre de Recherche du Centre Hospitalier de l'Universite de Montreal, Montreal, Quebec, Canada

Shiao-Ying Chang, PhD

• Liao, Min-Chun, Centre de Recherche du Centre Hospitalier de l'Universite de Montreal, Montreal, Quebec, Canada

Min-Chun Liao, PhD

• Rivard, Alain, Universite de Montreal, Montreal, Quebec, Canada

Alain Rivard, MD

• Ingelfinger, Julie R., Harvard Medical School, Boston, Massachusetts, United States

Julie R. Ingelfinger, MD

• Chan, John S.D., Centre de Recherche du Centre Hospitalier de l'Universite de Montreal, Montreal, Quebec, Canada

John S.D. Chan, PhD

• Zhang, Shao-Ling, Centre de Recherche du Centre Hospitalier de l'Universite de Montreal, Montreal, Quebec, Canada

Shao-Ling Zhang, PhD

Background

Acute kidney injury (AKI) caused by renal ischemia/reperfusion (R I/R) injury is a major clinical issue lacking viable therapies, and with incompletely delineated underlying mechanisms. Given the important roles of hedgehog interacting protein (Hhip) in glomerular endothelial cells (ECs), we asked whether Hhip knockout (KO) in ECs prevents R I/R-induced kidney injury in vivo and in vitro.

Methods

Both male Hhip^EC KO and control Hhip^fl/fl mice at 10-weeks of age were subjected to 45 minutes of unilateral R I/R or sham surgery along with contralateral nephrectomy. The time course of AKI was followed at Days 1, 3 and 7. We also studied naïve renal proximal tubular cells (IRPTCs) exposed to the conditioned media harvested from mouse endothelial cell (mECs) with or without Hhip (siRNA) ± cisplatin (20µM) treatment.

Results

Compared to the respective sham controls, R I/R mice (Hhip^EC KO and Hhip^fl/fl) lost body weight starting from Day 1 to Day 7. In line with the AKI time course, Hhip^fl/fl-R I/R mice had higher mortality with significant kidney apoptosis documented by IVISense™ Annexin-V 750 fluorescent imaging probe; increased urinary albumin-to-creatinine ratio; and displayed renal dysmorphology (PAS, Masson’s trichrome and Sirius red) with enhanced Cystatin C- and kidney injury molecule-1 immunoexpression in their kidneys. Notably, renal tubular cell senescence (SA-β-galactosidase, p21, p16, MCP-1 staining) was significantly increased in Hhip^fl/fl-R I/R mice. In contrast, those changes were significantly ameliorated in the kidneys of Hhip^EC KO -R I/R mice. In vitro, naïve IRPTCs exposed to the conditioned media harvested from mECs treated with cisplatin exhibited higher cellular senescent activity with enlargment of nuclear size with both mono- or multi-nuclei and increased cytoskeleton destabilization as evidenced by dysmorphic patterns of α-tubulin and F-actin staining. Those changes were largely prevented in naïve IRPTCs exposed to the conditioned media from Hhip KO mECs treated with cisplatin.

Conclusion

Our data suggest that Hhip KO in ECs prevented or ameliorated AKI-induced renal tubular injury. This potential protection may be mediated, at least in part, by the inhibition of Hhip-mediated tubular cell senescence.