HIV-1 Inhibitors Research Articles

Evaluation of COVID-19 protease and HIV inhibitors interactions.

The epidemic of the novel coronavirus disease (COVID-19) that started in 2019 has evoked an urgent demand for finding new potential therapeutic agents. In this study, we performed a molecular docking of anti-HIV drugs to refine HIV protease inhibitors and nucleotide analogues to target COVID-19. The evaluation was based on docking scores calculated by AutoDock Vina and top binding poses were analyzed. Our results suggested that lopinavir, darunavir, atazanavir, remdesivir, and tipranavir have the best binding affinity for the 3-chymotrypsin-like protease of COVID-19. The comparison of the binding sites of three drugs, namely, darunavir, atazanavir and remdesivir, showed an overlap region of the protein pocket. Our study showed a strong affinity between lopinavir, darunavir, atazanavir, tipranavir and COVID-19 protease. However, their efficacy should be confirmed by in vitro studies since there are concerns related to interference with their active sites.

A Review on Phytochemicals of the Genus Maytenus and Their Bioactive Studies.

The genus Maytenus is a member of the Celastraceae family, of which several species have long been used in traditional medicine. Between 1976 and 2021, nearly 270 new compounds have been isolated and elucidated from the genus Maytenus. Among these, maytansine and its homologues are extremely rare in nature. Owing to its unique skeleton and remarkable bioactivities, maytansine has attracted many synthetic endeavors in order to construct its core structure. In this paper, the current status of the past 45 years of research on Maytenus, with respect to its chemical and biological activities are discussed. The chemical research includes its structural classification into triterpenoids, sesquiterpenes and alkaloids, along with several chemical synthesis methods of maytansine or maytansine fragments. The biological activity research includes activities, such as anti-tumor, anti-bacterial and anti-inflammatory activities, as well as HIV inhibition, which can provide a theoretical basis for the better development and utilization of the Maytenus.

CHARACTERISATION AND STUDY OF 1- [2- (2-BENZOYLPHENOXY) ETHYL] -6-METHYLURACIL MECHANISM OF ACTION

The aim of the study is to identify 1-[2-(2-benzoylphenoxy) ethyl]-6-methyluracil using various methods of analysis, as well as to study its action mechanism against wild-type and mutant forms of HIV-1 reverse transcriptase (RT).Materials and methods. To characterize the structure of the test substance, a few kinds of analysis (X-ray diffraction, elemental, thermal) as well as a few kinds of spectroscopy (UV, IR, and NMR) have been used. The study of the action mechanism of the compound as a potential drug was carried out by evaluating the inhibitory activity against HIV-1 RT wild-type and its mutant forms corresponding to drug-resistant viral strains.Results. The studies have been carried out to confirm the structure of 1-[2-(2-benzoylphenoxy)ethyl]-6-methyluracil. The UV spectrum has a pronounced absorption maximum when measuring a solution of the substance in tetrahydrofuran at the concentration of 0.10 mg / ml. In the IR spectrum, there are specific bands in the range of 4000-370 cm–1. These factors make it possible to use UV and IR spectra to identify the test compound in the substance. It has also been established that the number and mutual arrangement of functional groups, the integrated intensity of signals in the 1H-NMR spectrum, as well as the structure of the carbon skeleton, correspond to the structure of 1-[2-(2-benzoylphenoxy) ethyl]-6-methyluracil. The results of studying the action mechanism showed that the test compound is an effective inhibitor of wild-type HIV-1 RT with an inhibition constant of 0.2 µM, as well as an enzyme inhibitor (mutation G190A) with an inhibition constant of 8 µM; enzyme (mutation Y181C) with an inhibition constant of 10 µM, as well as a reverse transcriptase (RT) inhibitor (mutation L100I, K103N, V106A) and a double mutant K103N / Y181C with an inhibition constant of more than 20 µM.Conclusion. As a result of the performed X-ray structural, elemental, 1H-NMR and 13C-NMR analyzes, the structure of 1-[2-(2-benzoylphenoxy)ethyl]-6-methyluracil has been confirmed. The possibility of using UV, IR and NMR spectroscopy, as well as thermal analyzes to confirm the authenticity during the verification of 1-[2-(2-benzoylphenoxy)ethyl]-6-methyluracil, has been shown. The developed methods can be used in the quality control and included in the draft of practice guidelines for the investigated substance. The studies of the action mechanism of the compound of HIV-1 RT reverse transcriptase have shown that this compound belongs to the group of non-nucleoside reverse transcriptase inhibitors (NNRTIs) of HIV-1.

Double Arylation of the Indole Side Chain of Tri- and Tetrapodal Tryptophan Derivatives Renders Highly Potent HIV-1 and EV-A71 Entry Inhibitors†.

We have recently described a new generation of potent human immunodeficiency virus (HIV) and EV-A71 entry inhibitors. The prototypes contain three or four tryptophan (Trp) residues bearing an isophthalic acid moiety at the C2 position of each side-chain indole ring. This work is now extended by both shifting the position of the isophthalic acid to C7 and synthesizing doubly arylated C2/C7 derivatives. The most potent derivative (50% effective concentration (EC50) HIV-1, 6 nM; EC50 EV-A71, 40 nM), 33 (AL-518), is a C2/C7 doubly arylated tetrapodal compound. Its superior anti-HIV potency with respect to the previous C2-arylated prototype is in consonance with its higher affinity for the viral gp120. 33 (AL-518) showed comparable antiviral activities against X4 and R5 HIV-1 strains and seems to interact with the tip and base of the gp120 V3 loop. Taken together, these findings support the interest in 33 (AL-518) as a useful new prototype for anti-HIV/EV71 drug development.

Capsid-specific nanobody effects on HIV-1 assembly and infectivity

The capsid (CA) domain of the HIV-1 precursor Gag (PrGag) protein plays multiple roles in HIV-1 replication, and is central to the assembly of immature virions, and mature virus cores. CA proteins themselves are composed of N-terminal domains (NTDs) and C-terminal domains (CTDs). We have investigated the interactions of CA with anti-CA nanobodies, which derive from the antigen recognition regions of camelid heavy chain-only antibodies. The one CA NTD-specific and two CTD-specific nanobodies we analyzed proved sensitive and specific HIV-1 CA detection reagents in immunoassays. When co-expressed with HIV-1 Gag proteins in cells, the NTD-specific nanobody was efficiently assembled into virions and did not perturb virus assembly. In contrast, the two CTD-specific nanobodies reduced PrGag processing, virus release and HIV-1 infectivity. Our results demonstrate the feasibility of Gag-targeted nanobody inhibition of HIV-1.

Human Beta-Defensin 2 and 3 Inhibit HIV-1 Replication in Macrophages.

Human beta-defensins (hBDs) are broad-spectrum antimicrobial peptides, secreted by epithelial cells of the skin and mucosae, and astrocytes, which we and others have shown to inhibit HIV-1 in primary CD4+ T cells. Although loss of CD4+ T cells contributes to mucosal immune dysfunction, macrophages are a major source of persistence and spread of HIV and also contribute to the development of various HIV-associated complications. We hypothesized that, besides T cells, hBDs could protect macrophages from HIV. Our data in primary human monocyte-derived macrophages (MDM) in vitro show that hBD2 and hBD3 inhibit HIV replication in a dose-dependent manner. We determined that hBD2 neither alters surface expression of HIV receptors nor induces expression of anti-HIV cytokines or beta-chemokines in MDM. Studies using a G-protein signaling antagonist in a single-cycle reporter virus system showed that hBD2 suppresses HIV at an early post-entry stage via G-protein coupled receptor (GPCR)-mediated signaling. We find that MDM express the shared chemokine-hBD receptors CCR2 and CCR6, albeit at variable levels among donors. However, cell surface expression analyses show that neither of these receptors is necessary for hBD2-mediated HIV inhibition, suggesting that hBD2 can signal via additional receptor(s). Our data also illustrate that hBD2 treatment was associated with increased expression of APOBEC3A and 3G antiretroviral restriction factors in MDM. These findings suggest that hBD2 inhibits HIV in MDM via more than one CCR thus adding to the potential of using β-defensins in preventive and therapeutic approaches.

Layer-by-Layer Assembled Nanostructured Lipid Carriers for CD-44 Receptor-Based Targeting in HIV-Infected Macrophages for Efficient HIV-1 Inhibition.

Macrophages act as a cellular reservoir in HIV infection. Elimination of HIV from macrophages has been an unfulfilled dream due to the failure of drugs to reach them. To address this, we developed CD44 receptor-targeted, novel hyaluronic acid (HA)-coated nanostructured lipid carriers (NLCs) of efavirenz via washless layer-by-layer (LbL) assembly of HA and polyallylamine hydrochloride (PAH). NLCs were subjected to TEM analysis, size and zeta potential, in vitro release and encapsulation efficiency studies. The uptake of NLCs in THP-1 cells was studied using fluorescence microscopy and flow cytometry. The anti-HIV efficacy was evaluated using p24 antigen inhibition assay. NLCs were found to be spherical in shape with anionic zeta potential (-23.66 ± 0.87 mV) and 241.83 ± 5.38 nm particle size. NLCs exhibited prolonged release of efavirenz during in vitro drug release studies. Flow cytometry revealed 1.73-fold higher uptake of HA-coated NLCs in THP-1 cells. Cytotoxicity studies showed no significant change in cell viability in presence of NLCs as compared with the control. HA-coated NLCs distributed throughout the cell including cytoplasm, plasma membrane and nucleus, as observed during fluorescence microscopy. HA-coated NLCs demonstrated consistent and significantly higher inhibition (81.26 ± 1.70%) of p24 antigen which was 2.08-fold higher than plain NLCs. The obtained results suggested preferential uptake of HA-coated NLCs via CD44-mediated uptake. The present finding demonstrates that HA-based CD44 receptor targeting in HIV infection is an attractive strategy for maximising the drug delivery to macrophages and achieve effective viral inhibition.

Effect of N'-Benzyl Substituted Uracil and the Analogues on HIV-1 Inhibition

The aim of the research is to study the effect of the synthesis of uracil derivatives on the HIV-1 activity. To achieve the goal, the following tasks were determined: to study the specificity of possible compounds for HIV-1 treatment; to synthesize uracil derivatives; to study the effect of the compounds on HIV-1 replication in vitro and select the most optimal concentrations, considering the cytotoxic effect; to determine the most effective anti-HIV-1 compounds for further research. Thus, nine new uracil analogues have been synthesized and proved to be inhibitors of HIV-1. Key structural modifications included replacement of the 6-chloro group of 1-benzyl-6-chloro-3-(3,5-dimethylbenzyl) uracil by other functional groups or N (1)-alkylation of 3-(3,5-dimethylbenzyl)-5-fluorouracil. These compounds showed only micromolar potency against HIV-1 in MT-4, though two of them; 6-azido-1-benzyl-3-(3,5-dimethylbenzyl) uracil and 6-amino-1-benzyl-3-(3,5-dimethylbenzyl) uracil were highly potent (half maximal effective concentration =0.081 and 0.069μM) and selective (selectivity index =679 and 658), respectively. Structure-activity relationships among the newly synthesized uracil analogues suggest the importance of the H-bond formed between 6-amino group of 6-amino-1-benzyl-3-(3,5-dimethylbenzyl) uracil and amide group of HIV-1 reverse transcriptase. Two 6-substituted 1-benzyl-3-(3,5-dimethylbenzyl) uracils, (6-azido-1-benzyl-3-(3,5-dimethylbenzyl) uracil and 6-amino-1-benzyl-3-(3,5-dimethylbenzyl) uracil) were discovered as novel anti-HIV agents. Compound’s activity against HIV-1 was determined based on inhibition of virus-induced cytopathogenicity in MT-4 cells. The compounds were tested for efficacy in infected cells and cytotoxicity. These compounds should be further pursued for their toxicity and pharmacokinetics in vivo as well as antiviral activity against non-nucleoside reverse transcriptase inhibitor-resistant strains. Thus, it will contribute to the development of a new generation of compounds effective against different viruses, considering their quickly mutation and increased resistance.

Lobostemon trigonus (Thunb.) H. Buek, a medicinal plant from South Africa as a potential natural microbicide against HIV-1

Ethnopharmacological relevanceThere have been different methods proposed to prevent the sexual transmission of HIV-1 and many of them have centered on the use of anti-retrovirals as microbicides. Given that a large section of the African population still relies on herbal medicine, Lobostemon trigonus (L. trigonus), a traditionally used medicinal plant in South Africa to treat HIV-1 was further investigated for its potential as a natural microbicide to prevent the sexual transmission of HIV-1. MethodsThe aerial parts of L. trigonus were oven-dried at 80 °C, ground, extracted with boiling water for 30 min and then filtered. The aqueous extract produced was then bioassayed using different HIV-1 inhibition assays. The active components were purified and chemically profiled using ultra-performance liquid chromatography/quadrupole time-of flight mass spectrometry (UPLC-qTOF-MS). The mechanism of HIV-1 inhibition was determined by fusion arrest assay and time of addition assay. Molecular modelling and molecular dynamic simulations, using Schrödinger, were used to better understand the molecule's mechanism of entry inhibition by evaluating their docking affinity and stability against the gp120 of HIV-1. ResultsThe aqueous extract of this plant had a broad spectrum of activity against different subtypes of the virus; neutralizing subtype A, B and C in the TZM-bl cells, with IC50 values ranging from 0.10 to 7.21 μg/mL. The extract was also inhibitory to the virus induced cytopathic effects in CEM-SS cells with an EC50 of 8.9 μg/mL. In addition, it inhibited infection in peripheral blood mononuclear cells (PBMC) and macrophages with IC50 values of 0.97 and 4.4 μg/mL, respectively. In the presence of vaginal and seminal simulants, and in human semen it retained its inhibitory activity albeit with a decrease in efficiency, by about 3-fold. Studies of the mode of action suggested that the extract blocked HIV-1 attachment to target cells. No toxicity was observed when the Lactobacilli strains, L. acidophilus, L. jensenii, and L. crispatus that populate the female genital tract were cultured in the presence of L. trigonus extract. UPLC-qTOF-MS analyses of the purified fraction of the extract, confirmed the presence of six compounds of which four were identified as rosmarinic acid, salvianolic acids B and C and lithospermic acid. The additional molecular dynamic simulations provided further insight into the entry inhibitory characteristics of salvianolic acid B against the HIV-1 gp120, with a stable pose being found within the CD4 binding site. ConclusionThe data suggests that the inhibitory effect of L. trigonus may be due to the presence of organic acids which are known to possess anti-HIV-1 properties. The molecules salvianolic acids B and C have been identified for the first time in L. trigonus species. Our study also showed that the L. trigonus extract blocked HIV-1 attachment to target cells, and that it has a broad spectrum of activity against different subtypes of the virus; thus, justifying further investigation as a HIV-1 microbicide.

NOVEL SARS-CoV-2 INHIBITORS FROM PHENETHYLTHIAZOLETHIOUREA DERIVATIVES USING HYBRID QSAR MODELS AND DOCKING SIMULATION

ABSTRACT Currently, there are several groups of HIV-1 virus inhibitors that could potentially be used in the treatment of SARS-CoV-2. Particularly, the phenethylthiazolethiourea compounds are capable of inhibiting HIV-1 RT and have been tested by IC50. This work contributed to the search for SARS-CoV-2 inhibitors; a group of these compounds was developed to obtain SARS-CoV-2 inhibitors. The hybrid QSARGA-ANN model with I(5)-HL(9)-O(1) architecture used for developing for HIV-1 inhibitors and it successfully predicted the pIC50 activities of six newly designed compounds. The predicted results of the pIC50 activity received from the QSARGA-ANN model agreed well with the docking simulation. The C-n6 new molecule that has been bound to the SARS-CoV-2 protein receptors (PDB ID: 6LU7) using docking simulation. It demonstrated a more effective activity against HIV-1 (PDB ID: 1ODW). This compound C-n6 exhibited the binding affinity for the HIV-1 protein (1ODW) is −23.6137 kJ.mol-1; for the target protein SARS-CoV-2 (6LU7), its binding affinity is −27.4235 kJ.mol-1. The retrosynthesis plan for the most active substance C-n6 1-(2-chloro-5-hydroxy-4-nitrophenethyl)-3- (thiazol-2-yl) thiourea has been successfully constructed. In this research the designed directions for new substances can generate the SARS-CoV-2 inhibitory drugs in a fast and reliable way.

High-resolution view of HIV-1 reverse transcriptase initiation complexes and inhibition by NNRTI drugs

Reverse transcription of the HIV-1 viral RNA genome (vRNA) is an integral step in virus replication. Upon viral entry, HIV-1 reverse transcriptase (RT) initiates from a host tRNALys3 primer bound to the vRNA genome and is the target of key antivirals, such as non-nucleoside reverse transcriptase inhibitors (NNRTIs). Initiation proceeds slowly with discrete pausing events along the vRNA template. Despite prior medium-resolution structural characterization of reverse transcriptase initiation complexes (RTICs), higher-resolution structures of the RTIC are needed to understand the molecular mechanisms that underlie initiation. Here we report cryo-EM structures of the core RTIC, RTIC–nevirapine, and RTIC–efavirenz complexes at 2.8, 3.1, and 2.9 Å, respectively. In combination with biochemical studies, these data suggest a basis for rapid dissociation kinetics of RT from the vRNA–tRNALys3 initiation complex and reveal a specific structural mechanism of nucleic acid conformational stabilization during initiation. Finally, our results show that NNRTIs inhibit the RTIC and exacerbate discrete pausing during early reverse transcription.

Glycyrrhizic Acid Derivatives as New Antiviral and Immune Modulating Agents

The search for new drugs to treat viral infections and immune deficiencies of various etiologies is still one of the most important tasks of medicinal chemistry, pharmacy, and medicine due to the widespread prevalence of a number of socially dangerous viral infections. This review focuses on the chemical modification of Glycyrrhizic acid (Gl), the main component of licorice root, which is currently a leading natural glycoside that is considered to be promising for the development of new antiviral agents. The review presents the results of studies conducted over the past 15 years to obtain a library of Gl acid derivatives for biological studies and to search for leader compounds. The synthesis of new biologically active derivatives and analogues (conjugates with amino acids and dipeptides, amino sugars, licorice triterpene acids conjugates with amino sugars, saponins and mono glycosides, and heterocyclic amides) was conducted, and their antiviral and immune modulating properties were studied. Potent inhibitors of HIV, SARS CoV, Epstein-Barr, and influenza A/H1N1 viruses and the stimulators of primary immune response were found among the Gl derivatives and analogues that were produced.

An insight on medicinal aspects of novel HIV-1 capsid protein inhibitors

A capsid is the protein shell of a virus, encircling its genetic material. The HIV capsid is erected from a single protein, known as capsid protein. The capsid of HIV-1 significantly involved in many processes of the virus life cycle, which makes it as a novel target for the new inhibitors. Recently many novel HIV-1 inhibitors binding to capsid proteins have been reported successfully. Most of these inhibitors can inhibit or accelerate the disassembly or assembly of the capsid, and some of them can inhibit reverse transcription. Unfortunately, none of them are currently approved by U.S. FDA. However, GS-6207, an inhibitor binds to the NTD-CTD interface with potent antiviral activity and the long metabolic cycle, is expected to be the first approved drug targeting HIV-1 capsid. Herein, we provide a concise report focusing on the recent prospective of HIV-1 capsid inhibitors in medicinal chemistry in order to enlighten drug design.

Performance of smoothly clipped absolute deviation as a variable selection method in the artificial neural network‐based QSAR studies

AbstractA hybrid of smoothly clipped absolute deviation (SCAD) and Levenberg‐ Marquardt artificial neural network (LM‐ANN) was used as an efficient approach (SCAD‐LM‐ANN) in the ANN‐based quantitative structure–activity relationship (QSAR) studies. The proposed technique (SCAD‐LM‐ANN) exploits the useful shrinkage nature of SCAD in the reduction of high dimensional data prior to modeling by the robust LM‐ANN method. The performance of the method was examined by establishing a QSAR model between about 3224 Dragon‐derived descriptors and biological activities (pEC50) for a set of thioacetamide/acetanilide derivatives as HIV inhibitors. SCAD method with the tenfold random splitting of data was applied to the data set in the absence of compounds in the external test set. A number of 11 descriptors were selected at a λ with the lowest cross‐validation error (λmin). The selected descriptors were used as inputs of the LM‐ANN modeling method. All parameters affecting model performance were optimized, and the LM‐ANN model with the architecture of 5‐5‐1 was selected as the optimal QSAR model. Several statistical parameters such as determination coefficient (R2) and mean square error (MSE) were calculated for the predicted pEC50 values for the external test set and the whole data set through the leave one out (LOO) technique. The results ( = 0.92, MSEtest = 0.12, = 0.81, and MSELOO = 0.12) prove the generalizability and predictability of the proposed SCAD‐LM‐ANN model. According to the established relationship in the recommended QSAR model, new derivatives were designed and suggested as new active HIV inhibitors for further studies. The accuracy of the suggested compounds was studied and confirmed by analyzing the ligand–receptor (LR) interactions derived from the molecular docking studies.

Design, synthesis, and structure activity relationship analysis of new betulinic acid derivatives as potent HIV inhibitors.

Prior modification of betulinic acid (1), a natural product lead with promising anti-HIV activity, produced 3-O-(3',3'-dimethylsuccinyl)betulinic acid (bevirimat, 3), the first-in-class HIV maturation inhibitor. After 3-resistant variants were found during Phase I and IIa clinical trials, further modification of 3 produced 4 with improved activity against wild-type and 3-resistant HIV-1. In continued efforts to optimize 1, 63 final products have now been designed, synthesized, and evaluated for anti-HIV-1 replication activity against HIV-1NL4-3 infected MT-4cell lines. Five known and 21 new derivatives were as or more potent than 3 (EC50 0.065μM), while eight new derivatives were as or more potent than 4 (EC50 0.019μM). These derivatives feature expanded structural diversity and chemical space that may improve the antiviral activity and address the growing resistance crisis. Structure-Activity Relationship (SAR) correlations were thoroughly analyzed, and a 3D Quantitative SAR model with high predictability was constructed to facilitate further rational design and development of new potent derivatives.

The Cost-Effectiveness and Budget Impact of Ibalizumab-uiyk for Adults with Multidrug-Resistant HIV-1 Infection in the United States.

Ibalizumab-uiyk (ibalizumab) is a first-in-class, long-acting, postattachment HIV-1 inhibitor for adults with multidrug-resistant (MDR) HIV-1 infection. This analysis examines the cost-effectiveness and budget impact of ibalizumab treatment for this difficult-to-treat population in the United States. A Markov model followed cohorts of adults with MDR HIV-1 infection through two final lines of antiretroviral therapy: ibalizumab + optimized background therapy (OBT) or OBT alone followed by nonsuppressive therapy. Model inputs were based on ibalizumab clinical trial data, market uptake projections, and published literature, with costs in 2019 dollars. The cost-effectiveness analysis assessed costs and health outcomes from a health care sector perspective for individuals receiving ibalizumab + OBT versus OBT alone over a lifetime time horizon. The budget-impact analysis estimated the impact on payer budgets of the introduction of ibalizumab over 3 years for a hypothetical commercial health plan. Compared with individuals receiving OBT alone, individuals receiving ibalizumab + OBT incurred higher costs but lived longer, healthier lives, with an incremental cost of $133,040 per QALY gained. For a hypothetical commercial health plan with 1 million members, the introduction of ibalizumab + OBT was estimated to increase budgets by $217,260, $385,245, and $560,310 ($0.018, $0.032, and $0.047 per member per month) in years 1, 2, and 3, respectively. These results were found to be robust in sensitivity and scenario analyses. Ibalizumab may represent a cost-effective and affordable option to improve health outcomes for individuals with MDR HIV-1 infection.

Identification of novel potent HIV-1 inhibitors by exploiting the tolerant regions of the NNRTIs binding pocket.

With our previously identified potent NNRTIs 25a and HBS-11c as leads, series of novel thiophene[3,2-d]pyrimidine and thiophene[2,3-d]pyrimidine derivatives were designed via molecular hybridization strategy. All the target compounds were evaluated for their anti-HIV-1 activity and cytotoxicity in MT-4cells. Compounds 16a1 and 16b1 turned out to be the most potent inhibitors against WT and mutant HIV-1 strains (L100I, K103N, and E138K), with EC50 values ranging from 0.007μM to 0.043μM. Gratifyingly, 16b1 exhibited significantly reduced cytotoxicity (CC50>217.5μM) and improved water solubility (S=49.3μg/mL at pH 7.0) compared to the lead 25a (S<1μg/mL at pH 7.0, CC50=2.30μM). Moreover, molecular docking was also conducted to rationalize the structure-activity relationships of these novel derivatives and to understand their key interactions with the binding pocket.

HIV-1 Env-Dependent Cell Killing by Bifunctional Small-Molecule/Peptide Conjugates.

A strategy has been established for the synthesis of a family of bifunctional HIV-1 inhibitor covalent conjugates with the potential to bind simultaneously to both the gp120 and gp41 subunits of the HIV-1 envelope glycoprotein trimeric complex (Env). One component of the conjugates is derived from BNM-III-170, a small-molecule CD4 mimic that binds to gp120. The second component, comprised of the peptide DKWASLWNW ("Trp3"), was derived from the N-terminus of the HIV-1 gp41 Membrane Proximal External Region (MPER) and found previously to bind to the gp41 subunit of Env. The resulting bifunctional conjugates were shown to inhibit virus cell infection with low micromolar potency and to induce lysis of the HIV-1 virion. Crucially, virolysis was found to be dependent on the covalent linkage of the BNM-III-170 and Trp3 domains, as coadministration of a mixture of the un-cross-linked components proved to be nonlytic. However, a significant magnitude of lytic activity was observed in Env-negative and other control pseudoviruses, suggesting parallel mechanisms of action of the conjugates involving Env interaction and direct membrane disruption. Computational modeling suggested strong membrane-binding activity of BNM-III-170, which may underly the nonspecific virolytic effects of the conjugates. To investigate the scope of the membrane effect, cell-based cytotoxicity and membrane permeability assays were performed employing flow cytometry. Here, we observed a dose-dependent and specific cytotoxic effect on HIV-1 Env-expressing cells by the small-molecule bifunctional inhibitor. Most importantly, Env-negative cells were not susceptible to the cytotoxic effect upon exposure to this construct at concentrations where cell-killing effects were observed for Env-positive cells. Computational structural modeling supports a mechanism in which the bifunctional inhibitors bind to the gp120 and gp41 subunits in tandem in open-state Env trimers and induce relative motion of the gp120 subunits consistent with models of Env inactivation. This observation supports the idea that the cell-killing effect of the small-molecule bifunctional inhibitor is due to specific Env conformational triggering. This work lays important groundwork to advance a small-molecule bifunctional inhibitor approach for eliminating Env-expressing infected cells and the eradication of HIV-1.

Gag Protein Oriented Supramolecular Nets as Potential HIV Traps.

For HIV/AIDS treatment, the cocktail therapy which uses a combination of anti-retroviral drugs remains the most widely accepted practice. However, the potential drug toxicity, patient tolerability, and emerging drug resistance have limited its long-term efficiency. Here, we design a HIV Gag protein-targeting redox supramolecular assembly (ROSA) system for potential HIV inhibition. An assembling precursor was constructed through conjugation of an oxidation-activatable fluorogenic compound BQA with a selected tetrapeptide GGFF. Since BQA shares a similar structure with the known Gag inhibitor, the precursor could bind to HIV Gag protein with moderate affinity. Moreover, after oxidation, the corresponding nanofibers could bind to Gag protein and trap HIV to realize virus control, thus providing a potential anti-HIV strategy.

Design and Synthesis of Quinolizidine Derivatives as Influenza Virus and HIV-1 Inhibitors.

We have previously reported that a quinolizidine natural product, aloperine, and its analogs can inhibit influenza virus and/or HIV-1 at low μM concentrations. The main goal of this study was to further optimize aloperine for improved anti-influenza virus activity. Structural modifications have been focused on the N12 position of aloperine scaffold. Conventional chemical synthesis was used to obtain derivatives with improved antiviral activities. The anti-HIV and anti-influenza virus activities of the synthesized compounds were determined using an MT4 cell-based HIV-1 replication assay and an anti- influenza virus infection of MDCK cell assay, respectively. Aloperine derivatives can be classified into three activity groups: those that exhibit anti-HIV activity only, anti-influenza virus only, or activity against both viruses. Aloperine optimized for potent anti-influenza activity often lost anti-HIV-1 activity, and vice versa. Compound 19 inhibited influenza virus PR8 replication with an IC50 of 0.091 μM, which is approximately 160- and 60-fold more potent than aloperine and the previously reported aloperine derivative compound 3, respectively. The data suggest that aloperine is a privileged scaffold that can be modified to become a selective antiviral compound with markedly improved potency against influenza virus or HIV-1.