The HIV-1 integrase-LEDGF allosteric inhibitor MUT-A: resistance profile, impairment of virus maturation and infectivity but without influence on RNA packaging or virus immunoreactivity

Abstract

Background HIV-1 Integrase (IN) interacts with the cellular co-factor LEDGF/p75 and tethers the HIV preintegration complex to the host genome enabling integration. Recently a new class of IN inhibitors was described, the IN-LEDGF allosteric inhibitors (INLAIs). Designed to interfere with the IN-LEDGF interaction during integration, the major impact of these inhibitors was surprisingly found on virus maturation, causing a reverse transcription defect in target cells.Results Here we describe the MUT-A compound as a genuine INLAI with an original chemical structure based on a new type of scaffold, a thiophene ring. MUT-A has all characteristics of INLAI compounds such as inhibition of IN-LEDGF/p75 interaction, IN multimerization, dual antiretroviral (ARV) activities, normal packaging of genomic viral RNA and complete Gag protein maturation. MUT-A has more potent ARV activity compared to other INLAIs previously reported, but similar profile of resistance mutations and absence of ARV activity on SIV. HIV-1 virions produced in the presence of MUT-A were non-infectious with the formation of eccentric condensates outside of the core. In studying the immunoreactivity of these non-infectious virions, we found that inactivated HIV-1 particles were captured by anti-HIV-specific neutralizing and non-neutralizing antibodies (b12, 2G12, PGT121, 4D4, 10-1074, 10E8, VRC01) with efficiencies comparable to non-treated virus. Autologous CD4+ T lymphocyte proliferation and cytokine induction by monocyte-derived dendritic cells (MDDC) pulsed either with MUT-A-inactivated HIV or non-treated HIV were also comparable.Conclusions Although strongly defective in infectivity, HIV-1 virions produced in the presence of the MUT-A INLAI have a normal protein and genomic RNA content as well as B and T cell immunoreactivities comparable to non-treated HIV-1. These inactivated viruses might form an attractive new approach in vaccine research in an attempt to study if this new type of immunogen could elicit an immune response against HIV-1 in animal models.Electronic supplementary materialThe online version of this article (10.1186/s12977-017-0373-2) contains supplementary material, which is available to authorized users.

Multifaceted HIV integrase functionalities and therapeutic strategies for their inhibition

“…ALLINI compounds are built around heterocyclic cores, such as pyridine (171,200), thiophene (201), quinoline (165,167,168,170,197,(202)(203)(204), isoquinoline (205), thienopyridine (167,206) (Fig. 4B), or naphthyridine (207); additional chemotypes have been described in the patent literature (reviewed in Ref.…”

“…231), ALLINIs are specific for HIV-1 and do not inhibit closely related primate lentiviruses such as HIV-2 or simian immunodeficiency virus from rhesus macaques (167,201,209). Eccentric HIV-1 particles produced by exposure to the thiophene ALLINI MUT-A displayed immunoreactivity characteristics similar to mock-treated virions, indicating a potential novel avenue for chemically inactivated immunogens as vaccine candidates (201). Given the specificity of ALLINIs for HIV-1 IN, intensive safety evaluations necessitated by such approaches will likely require chimeric SHIV strains that carry HIV-1 IN (232).…”

“…Resistance against quinoline and thienopyridine ALLINIs is readily selected in cell culture, with most changes mapping to IN residues in the vicinity of the LEDGF/p75-binding pocket (165,167,(201)(202)(203)212). Whereas some of these, such as Thr-174, are invariant among circulating HIV-1 strains, others, such as Ala-124 and Ala-125, are highly polymorphic in nature (238 -241) (reviewed in Ref.…”

“…Whereas Asn-124 and Ala-125 each conferred ϳ50-fold resistance to pyridine ALLINI compound 20 (200) and thiophene ALLINI MUT-A (215), respectively, naphthyridine ALLINI compound 23 remained active against such strains (207). Counterscreening against representative polymorphic strains such as these, as well as viruses containing changes such as A128T and T174I that are commonly selected during virus passage (165,167,171,(201)(202)(203)212), is important to the ongoing development of the ALLINI drug class.…”

Structure-function analyses unravel distinct effects of allosteric inhibitors of HIV-1 integrase on viral maturation and integration

“…These biochemical activities were comparable to those of previously described INLAI compounds BI-D and BI-224436 (Table 1). We also checked by cryoelectron microscopy (cryo-EM) that MUT-A treatment during production of HIV-1 induced the formation of virus particles containing aberrant cores, from which the viral ribonucleoprotein complex is excluded, leading to the formation of eccentric condensates (28). In multiple-round antiviral assays on MT4 cells infected with HIV-1 NL4-3 strain, MUT-A has a strong ARV activity with a 31 nM EC50, slightly more potent than BI-224436, and roughly six-fold more efficient than the BI-D racemate (EC50=0.19 µM).…”