Abstract: FR-PO233

HIV and Interferon (IFN)-y Facilitate Parietal Epithelial Cell Transition through Induction of APOL1

Session Information

Category: Cell Biology

  • 202 Apoptosis, Proliferation, Autophagy, Cell Senescence, Cell Transformation

Authors

  • Kumar, Vinod, Fienstine Institute for Medical Research, New York, New York, United States
  • Skorecki, Karl, Rambam Health Care Campus, Haifa, Israel
  • Singhal, Pravin C., North Shore LIJ Health System, Great Neck, New York, United States
  • Lan, Xiqian, Feinstein Institute for Medical Research, Great Neck, New York, United States
  • Aslam, Rukhsana, Feinstein Institute for medical research, Glenoaks, New York, United States
  • Hussain, Ali, Feinstein Institute of Medical Research, New York, New York, United States
  • Marashi Shoshtari, Seyedeh Shadafarin, The Feinstein Institute for Medical Research, Manhasset, New York, United States
  • Bhooplapur, Manali, Feinstein Institute for medical research, Glenoaks, New York, United States
  • Chowdhary, Sheetal, Feinstein Institute of Medical Research, New York, New York, United States
  • Meyer-Schwesinger, Catherine, University of Hamburg, Hamburg, Germany
  • Malhotra, Ashwani, Feinstein Inst.Med research and NSLIJ, Manhasset, New York, United States
Background

Genetic epidemiology indicated that HIV-infected patients carrying APOL1 risk alleles with African ancestry carry a risk of developing HIV-associated neprhopathy at 10 times higher rates when compared to patients carrying APOL1 (wild-type). Podocytes (PDs) express APOL1 constitutively and this expression is enhanced by HIV and IFN-y. However, parietal epithelial cells (PECs) do not express APOL1. Both PDs and PECs are evolved from the same mesenchymal cells during embryogenesis. Since APOL1 expression seems to be a differentiating phenotypic molecule between PECs and PDs, we wished to consider its potential role in distinct cellular phenotype determination. We hypothesize that HIV could be facilitating PECs transition to PDs through the induction of APOL1.

Methods

Immortalized PECs proliferate at 33°C and differentiate (transit) to podocytes at 37°C. PECs were transduced with either vector (PECV) or HIV (NL4-3, PECHIV) and incubated for 48 hours at 33°C (n=4). In another set of experiments, PECs were incubated in media containing different concentrations of IFN-Y (0, 5, 10, 15, 20 nM) for 48 hours at 33° (n=4). To establish a causal relationship, PECV and PECHIV were transfected with either control or APOL1 siRNA (n=4). To confirm the role in PECs transition, mouse (M) PDs, which do not express APOL1, were transduced with either vector or APOL1 lentivirus (n=4). Proteins and RNAs were extracted. Protein blots were probed for APOL1, markers of PECs (PAX2, and Claudin 1) and PDs (WT1, nephrin, podocalyxin, and podocin) and reprobed for GAPDH. cDNAs were amplified for APOL1, WT1, podocalyxin, nephrin, and podocin.

Results

HIV induced APOL1 expression in PECs. IFN-γ also induced APOL1 expression in PECs in a dose dependent manner. PECHIV/IFN-γ-treated PECs displayed induction of nephrin, enhanced expression of WT1 (2.5-fold) and podocalyxin (3-fold) but down regulation of PAX2 (2-fold). PECHIVs with knockout APOL1 displayed down regulation of WT1, podocalyxin, and podocin; on the other hand, mouse podocytes (MPDs) expressing APOL1 displayed enhanced expression of WT1, podocalyxin, and podocin when compared to MPDVector.

Conclusion

HIV and IFN-y stimulate PECs transition through induction of APOL1.

Funding

  • NIDDK Support