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2337 Restriction of HIV-1 Infection in Sickle Cell Disease and Trait

Program: Oral and Poster Abstracts
Session: 102. Regulation of Iron Metabolism: Poster II
Hematology Disease Topics & Pathways:
Adult, Diseases, viral, Biological Processes, Study Population, Infectious Diseases, iron metabolism, molecular interactions
Sunday, December 2, 2018, 6:00 PM-8:00 PM
Hall GH (San Diego Convention Center)

Namita Kumari, PhD1,2*, Miguel de Mulder, PhD3*, Javed Khan, PhD4*, Asrar Ahmad, PhD5*, Songping Wang6*, Hatajai Lassiter7*, Nathan Smith8*, Nowah Kokou Apeadoufia Afangbedji1*, Andrey Ivanov, PhD6*, Mitsu Shah4*, Sharmin Diaz6*, Sohail Rana, MD9*, Douglas Nixon, PhD10* and Sergei Nekhai, PhD2

1Center for Sickle Cell Disease, Howard University, Washington, DC
2Department of Medicine, Howard University, Washington, DC
3Division of Infectious Diseases, Weill Cornell Medicine, New York, NY
4Department of Medicine, ,Howard University, Washington DC, DC
5Howard University, Center for Sickle Cell Disease, Washington DC, DC
6Center for Sickle Cell Disease, Howard University, Washington DC, DC
7Center for Sickle Cell Disease, Howard University, , Washington DC, DC
8Center for Sickle Cell Disease, Howard University, Washigton, DC
9Howard University, Washington DC, DC
10Division of Infectious Diseases, Weill Cornell Medical College, New York City, NY

BACKGROUND: Human immunodeficiency virus type 1 (HIV-1) replication is controlled by host intrinsic antiviral restriction factors some of which are counteracted by HIV-1 accessory proteins. We recently showed that ex vivo HIV-1 infection is suppressed in PBMCs obtained from Sickle Cell Disease (SCD) patients. The inhibition was mediated in part by SAMHD1 and NF-κB inhibitor, IkBα and triggered by ferroportin, an iron export protein. Ferroportin expression reduced intracellular iron levels and inhibited cellular CDK2 activity leading to reduction of SAMHD1 phosphorylation and increased expression of IkBα.

OBJECTIVES: The study was designed to further clarify the mechanism of HIV-1 inhibition in SCD and identify additional HIV-1 restriction factors that may contribute to the restriction mechanism.

METHODS: A customized array was utilized to determine the expression of restriction factors in SCD PBMCs. The shRNA-mediated knockdowns of the identified genes were used to further validate the role of these factors in HIV-1 replication in cultured and primary cells. HIV-1BAL and VSVG-pseudotyped pNL4-3.Luc.R-E-virus was used to analyze HIV-1 replication.

RESULTS: Overexpression of ferroportin in THP-1 cells led to increased expression of HO-1 and p21 and reduced phosphorylation of SAMHD1. Inhibition of HO-1 and p21 by small molecules increased HIV-1 replication in SCD PBMCs suggesting that these factors contributed to the restriction mechanism. Knocking down SAMHD1 in SCD PBMC did not fully restore HIV-1 replication pointing to additional restriction factors. Analysis of HIV-1 restriction factors in SCD PBMCs using customized array showed increased expression of APOBECs, TRIMs, CH25H, CPSF6, CTR9, EIF2ak2, IFI16, MX2, PML and RTF1 mRNAs. We next tested the effect of SCD trait on HIV-1 infection ex vivo and in vivo. PBMCs obtained from SCD trait individuals showed restricted HIV-1 infection with HIV-1 IIIB virus. To further validate these findings, we compared 9 trait (HbAS) HIV-1 infected individuals with 107 non-SCD (HbAA or HbAC) HIV-1 infected individuals from Howard University HIV clinic. HIV-1 viral load and levels of HIV-1 env and gag were significantly lower in HIV-1 infected SCD trait subjects. Expression of HO-1, p21 were increased and RNR2 expression was reduced in SCD trait PBMCs. Small molecule inhibitors of HO-1 and p21 induced HIV-1 replication in SCD trait PBMCs.

CONCLUSIONS: Our findings point to HO-1 and p21 as factors that, in addition to SAMHD1 and IKBα, mediate HIV-1 restriction in SCD. In SCD trait, HO-1, p21 and RNR2 play a key role in ex vivo HIV-1 restriction. Thus HIV-1 infection is deregulated not only in SCD patients but also in SCD trait individuals. The HIV-1 restriction is mediated by iron-activated antiviral restriction factors.

ACKNOWLEDGMENTS: This work was supported by NIH Research Grants (1P50HL118006, 1R01HL125005, 5G12MD007597, 1UM1AI26617 and P30AI087714). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Disclosures: Nekhai: NIAID, NIH: Research Funding; NIMHD, NIH: Research Funding; NHLBI, NIH: Research Funding.

*signifies non-member of ASH