# Development of natural product inhibitors of Nef for clearance of HIV reservoirs

> **NIH NIH R01** · UNIVERSITY OF MICHIGAN AT ANN ARBOR · 2020 · $844,572

## Abstract

Current combined antiretroviral therapies (cART) suppress viral levels in the blood but do not eradicate
reservoirs of cells harboring integrated copies of HIV proviral genomes. These cells persist in part because the
provirus maintains a latent state that evades the immune response and viral cytopathic effect. Approaches to
clear reservoirs by reactivating latent cells have provided evidence that latency can be reversed in vivo,
however reversal of latency alone has not been sufficient to reduce latent reservoirs. Efforts are now in place
to couple latency reactivation with strategies to eradicate the infected cells – such as by design and activation
of more efficacious anti-HIV cytotoxic T lymphocytes (CTLs). Another key player is Nef, an accessory protein
encoded by HIV, which is a primary focus of our proposed research. Because Nef inhibits the activity of anti-
HIV CTLs, a potent inhibitor of this protein would help achieve HIV eradication. One of the main functions of
Nef is the down-modulation of major histocompatibility complex class I encoded proteins (MHC-I), masking
infection from the host immune system and allowing HIV infected cells to persist. Combination therapy with
latency antagonists plus Nef inhibitors could act synergistically to clear HIV reservoirs. To date, no Nef inhibitor
has achieved potent restoration of MHC-I in the presence of Nef. We developed a high-throughput assay to
identify inhibitors of Nef-mediated MHC-I downregulation, and a screen of natural product extracts (NPEs)
yielded 10 hits with Nef inhibitory activity. We identified a number of related compounds, as the active
component in several of these extracts. The pure natural products potently restore surface expression of MHC-
I in the presence of Nef without inhibiting its other activities. We tested a number of structurally related
compounds within this natural product family and identified two that possess pM to nM potencies in human
primary cells. Based on this strong preliminary data, we believe that further enhancing the Nef inhibitory activity
of these molecules through analog development will yield a safe anti-Nef drug. Therefore, we plan to (A)
optimize these inhibitors by further separating and characterizing the anti-Nef effect from off-target activities to
identify a lead drug candidate for development and (B) determine the mechanism by which the inhibitor
disrupts Nef-mediated MHC-I downmodulation so that optimization can be conducted more intelligently. These
goals will be achieved through the following specific aims: (1) Conduct lead compound structural optimization
to improve pharmaceutical properties. (2) Perform a detailed functional analysis of all promising analogs to
identify ideal lead compounds and (3) Determine the mechanism by which the natural product-derived inhibitor
disrupts Nef-mediated MHC-I downmodulation including target identification and biochemical studies. From this
work, we expect to generate a new class of compounds that...

## Key facts

- **NIH application ID:** 9965744
- **Project number:** 5R01AI148383-02
- **Recipient organization:** UNIVERSITY OF MICHIGAN AT ANN ARBOR
- **Principal Investigator:** Kathleen L. Collins
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $844,572
- **Award type:** 5
- **Project period:** 2019-07-01 → 2024-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9965744

## Citation

> US National Institutes of Health, RePORTER application 9965744, Development of natural product inhibitors of Nef for clearance of HIV reservoirs (5R01AI148383-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9965744. Licensed CC0.

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