HIV-1 Protease Research Articles

Prediction of differential Gag versus Env responses to a mosaic HIV-1 vaccine regimen by HLA class I alleles.

HLA class I variation has the strongest effect genome-wide on outcome after HIV infection, and as such, an understanding of the impact of HLA polymorphism on response to HIV vaccination may inform vaccine design. We sought HLA associations with HIV-directed immunogenicity in the phase 1/2a APPROACH vaccine trial, which tested vaccine regimens containing mosaic inserts in Ad26 and MVA vectors, with or without a trimeric gp140 protein. While there were no HLA allelic associations with the overall cellular immune response to the vaccine assessed by ELISpot (Gag, Pol, and Env combined), significant associations with differential response to Gag compared to Env antigens were observed. Notably, HLA class I alleles known to associate with disease susceptibility in HIV natural history cohorts are associated with stronger Env-directed responses, whereas protective alleles are associated with stronger Gag-directed responses. Mean viral loads determined for each HLA allele in untreated individuals correlated negatively with the strength of the Gag response minus the Env response in Black vaccinees based on both ELISpot and CD8+ T cell ICS responses. As the association of T cell responses to conserved Gag epitopes with lower viral load in untreated individuals is well established, our data raise the possibility that the Ad26.Mos.HIV vaccine may induce more effective cellular responses in those with HLA alleles that confer improved virologic control in untreated HIV infection.IMPORTANCENo vaccine tested to date has shown sufficient efficacy against HIV infection. A vaccine that induces robust responses in one individual may fail to do so in another individual due to variation in HLA class I genes, loci central to the immune response. Extensive data have shown the strong effect of HLA variation on outcome after HIV infection, but very little is known about the effect of such variation on HIV vaccine success. Here, we identify a link between the effect of HLA variation on HIV disease outcome and immune responses to an HIV vaccine. HLA variants associated with better HIV control after infection also induce stronger responses against the HIV Gag protein relative to the Env protein after vaccination. Given the virologic control conferred by responses to Gag in natural history of HIV infection, these data suggest that HLA alleles conferring protection after HIV infection may also support a more effective cellular response to HIV vaccination.

Quantitative Prediction of Human Immunodeficiency Virus Drug Resistance.

Drug resistance of pathogens, including viruses, is one of the reasons for decreased efficacy of therapy. Considering the impact of HIV type 1 (HIV-1) on the development of progressive immune dysfunction and the rapid development of drug resistance, the analysis of HIV-1 resistance is of high significance. Currently, a substantial amount of data has been accumulated on HIV-1 drug resistance that can be used to build both qualitative and quantitative models of HIV-1 drug resistance. Quantitative models of drug resistance can enrich the information about the efficacy of a particular drug in the scheme of antiretroviral therapy. In our study, we investigated the possibility of developing models for quantitative prediction of HIV-1 resistance to eight protease inhibitors based on the analysis of amino acid sequences of HIV-1 protease for 900 virus variants. We developed random forest regression (RFR), support vector regression (SVR), and self-consistent regression (SCR) models using binary vectors containing values from 0 or 1, depending on the presence of a specific peptide fragment in each amino acid sequence as independent variables, while fold ratio, reflecting the level of resistance, was the predicted variable. The SVR and SCR models showed the highest predictive performances. The models built demonstrate reasonable performances for eight out of nine (R2 varied from 0.828 to 0.909) protease inhibitors, while R2 for predicting tipranavir fold ratio was lower (R2 was 0.642). We believe that the developed approach can be applied to evaluate drug resistance of molecular targets of other viruses where appropriate experimental data are available.

Newly developed peptide-ELISA successfully detected anti-IgG antibodies against Maedi-Visna virus in sheep

Maedi Visna Virus (MVV) is a retrovirus that can infect sheep. There is still no effective therapy or vaccine against this virus and timely diagnosis is important to combat the complications of the disease. In this study, we aimed to develop an ELISA using peptides derived from gag protein as antigen. For this purpose, B cell epitopes of gag protein were predicted and a docking analysis with the B cell receptor was performed to select peptides to be used in ELISA. After three soluble epitopes with the highest antigenicity were produced as peptides, the immunogenicity of each peptide was determined by ELISA using sheep serum samples categorized as MVV positive (n=24) and negative (n=13). Subsequently, in house ELISA using above mentioned immunogenic peptides as antigen was used to investigate MVV seroprevalence in sheep (n=88). According to the results, among three peptides, two of them strongly reacted with MVV positive serum samples and the mean absorbance values detected among positive and negative serum samples were statistically significant, indicating that these peptides were immunogenic (P=0.016 and P=0.038). The third peptide also reacted with positive serum samples but the mean absorbance value was not statistically significant and this peptide was considered non-immunogenic (P=0.175). The immunogenic two peptides showed the same high sensitivity and specificity values of 91.60 and 92.80 according to the commercial kit. Moreover, MVV seroprevalence detected by peptide-ELISAs using CKQGSKE and CRPQGKAGHKG peptides as antigen was 3.40 % and 4.5 %, respectively. As a result, it was shown that these peptides can be successfully used for serological diagnosis of MVV.

Evaluating the Expression Levels of Human Endogenous Retrovirus-K 10 (HERV-K10) Gag as a Biomarker in Prostate Cancer Tissue.

Prostate cancer is one of the most common major health problems. Several risk factors are potentially involved in its development. Therefore, a biomarker capable of early diagnosis is necessary to facilitate the early detection and treatment of prostate cancer. Human endogenous retroviruses (HERVs) are abnormally expressed in various diseases. Our study aims to evaluate the specific role of HERV K-10 gag expressions in the progression of prostate cancer. For this, we collected a set of 50 prostate tumor tissue samples as well as 50 healthy tissue samples. After extracting RNA from the prostate samples, we analyzed the expression of HERV-K gag using quantitative real-time PCR (qRT-PCR). The resulting data revealed a significant correlation of HERV-K gag expression in malignant regions of the prostate in men with prostate cancer than in men without prostate cancer (p < 0.05). The presence of the HERV-K gag protein was detected in 10 of 50 tumor samples (20%), while no healthy samples presented this protein. These results suggest that increased HERV-K gag RNA and protein expression could serve as a sensitive and specific biomarker of prostate malignancy in this cohort of prostate carcinoma patients, further supporting its potential as a promising clinical marker.

Development of Anti-HIV Therapeutics: From Conventional Drug Discovery to Cutting-Edge Technology.

The efforts to discover HIV therapeutics have continued since the first human immunodeficiency virus (HIV) infected patient was confirmed in the 1980s. Ten years later, the first HIV drug, zidovudine (AZT), targeting HIV reverse transcriptase, was developed. Meanwhile, scientists were enlightened to discover new drugs that target different HIV genes, like integrase, protease, and host receptors. Combination antiretroviral therapy (cART) is the most feasible medical intervention to suppress the virus in people with HIV (PWH) and control the epidemic. ART treatment has made HIV a chronic infection rather than a fatal disease, but ART does not eliminate latent reservoirs of HIV-1 from the host cells; strict and life-long adherence to ART is required for the therapy to be effective in patients. In this review, we first discussed the scientific history of conventional HIV drug discovery since scientists need to develop more and more drugs to solve drug-resistant issues and release the side effects. Then, we summarized the novel research technologies, like gene editing, applied to HIV treatment and their contributions to eliminating HIV as a complementary therapy.

AAV gene replacement therapy for treating MPS IIIC: Facilitating bystander effects via EV-mRNA cargo.

MPS IIIC is a lysosomal storage disease caused by mutations in heparan-α-glucosaminide N-acetyltransferase (HGSNAT), for which no treatment is available. Because HGSNAT is a trans-lysosomal-membrane protein, gene therapy for MPS IIIC needs to transduce as many cells as possible for maximal benefits. All cells continuously release extracellular vesicles (EVs) and communicate by exchanging biomolecules via EV trafficking. To address the unmet need, we developed a rAAV-hHGSNATEV vector with an EV-mRNA-packaging signal in the 3'UTR to facilitate bystander effects, and tested it in an in vitro MPS IIIC model. In human MPS IIIC cells, rAAV-hHGSNATEV enhanced HGSNAT mRNA and protein expression, EV-hHGSNAT-mRNA packaging, and cleared GAG storage. Importantly, incubation with EVs led to hHGSNAT protein expression and GAG contents clearance in recipient MPS IIIC cells. Further, rAAV-hHGSNATEV transduction led to the reduction of pathological EVs in MPS IIIC cells to normal levels, suggesting broader therapeutic benefits. These data demonstrate that incorporating the EV-mRNA-packaging signal into a rAAV-hHGSNAT vector enhances EV packaging of hHGSNAT-mRNA, which can be transported to non-transduced cells and translated into functional rHGSNAT protein, facilitating cross-correction of disease pathology. This study supports the therapeutic potential of rAAVEV for MPS IIIC, and broad diseases, without having to transduce every cell.

The assembly-defective phenotype of an FIV Gag polyprotein containing the SIV nucleocapsid zinc finger motifs is reversed by including the SIV SP2 domain in the chimeric protein

To gain insight into the functional relationship between the nucleocapsid (NC) domains of the Gag polyproteins of feline and simian immunodeficiency viruses, FIV and SIV, respectively, we generated two FIV Gag chimeric proteins containing different SIV NC and gag sequences. A chimeric FIV Gag protein (NC1) containing the SIV two zinc fingers motifs was incapable of assembling into virus-like particles. By contrast, another Gag chimera (NC2) differing from NC1 by the replacement of the C-terminal region of the FIV NC with SIV SP2 produced particles as efficiently as wild-type FIV Gag. Of note, when the chimeric NC2 Gag polyprotein was expressed in the context of the proviral DNA in feline CrFK cells, wild-type levels of virions were produced which encapsidated 50% of genomic RNA when compared to the wild-type virus.

Diastereoselective Synthesis of the HIV Protease Inhibitor Darunavir and Related Derivatives via a Titanium Tetrachloride-Mediated Asymmetric Glycolate Aldol Addition Reaction.

Darunavir is a potent HIV protease inhibitor that has been established as an effective tool in the fight against the progression of HIV/AIDS in the global community. The successful application of this drug has spurred the development of derivatives wherein strategic regions (e.g., P1, P1', P2, and P2') of the darunavir framework have been structurally modified. An alternate route for the synthesis of darunavir and three related P1 and P1' derivatives has been developed. This synthetic pathway involves the use of a Crimmins titanium tetrachloride-mediated oxazolidine-2-thione-guided asymmetric glycolate aldol addition reaction. The resultant aldol adduct introduces the P1 fragment of darunavir via an aldehyde. Transamidation with a selected amine (isobutylamine or 2-ethyl-1-butylamine) to cleave the auxiliary yields an amide wherein the P1' component is introduced. From this stage, the amide is reduced to the corresponding β-amino alcohol and the substrate is then bis-nosylated to introduce the requisite p-nitrobenzenesulfonamide component and activate the secondary alcohol for nucleophilic substitution. Treatment with sodium azide yielded the desired azides, and the deprotection of the p-methoxyphenoxy group is achieved with the use of ceric ammonium nitrate. Finally, hydrogenation to reduce both the aniline and azide functionalities with concurrent acylation yields darunavir and its derivatives.

Investigating how HIV-1 antiretrovirals differentially behave as substrates and inhibitors of P-glycoprotein via molecular dynamics simulations

HIV-1 can rapidly infect the brain upon initial infection, establishing latent reservoirs that induce neuronal damage and/or death, resulting in HIV-Associated Neurocognitive Disorder. Though anti-HIV-1 antiretrovirals (ARVs) suppress viral load, the blood-brain barrier limits drug access to the brain, largely because of highly expressed efflux proteins like P-glycoprotein (P-gp). While no FDA-approved P-gp inhibitor currently exists, HIV-1 protease inhibitors show promise as partial P-gp inhibitors, potentially enhancing drug delivery to the brain. Herein, we employed docking and molecular dynamics simulations to elucidate key differences in P-gp’s interactions with several antiretrovirals, including protease inhibitors, with known inhibitory or substrate-like behaviors towards P-gp. Our results led us to hypothesize new mechanistic details of small-molecule efflux by and inhibition of P-gp, where the “Lower Pocket” in P-gp’s transmembrane domain serves as the primary initial site for small-molecule binding. Subsequently, this pocket merges with the more traditionally studied drug binding site—the “Upper Pocket”—thus funneling small-molecule drugs, such as ARVs, towards the Upper Pocket for efflux. Furthermore, our results reinforce the understanding that both binding energetics and changes in protein dynamics are crucial in discerning small molecules as non-substrates, substrates, or inhibitors of P-gp. Our findings indicate that interactions between P-gp and inhibitory ARVs induce bridging of transmembrane domain helices, impeding P-gp conformational changes and contributing to the inhibitory behavior of these ARVs. Overall, insights gained in this study could serve to guide the design of future P-gp-targeting therapeutics for a wide range of pathological conditions and diseases, including HIV-1.

Comparative analysis of retroviral Gag-host cell interactions: focus on the nuclear interactome

Retroviruses exploit host proteins to assemble and release virions from infected cells. Previously, most studies focused on interacting partners of retroviral Gag proteins that localize to the cytoplasm or plasma membrane. Given that several full-length Gag proteins have been found in the nucleus, identifying the Gag-nuclear interactome has high potential for novel findings involving previously unknown host processes. Here we systematically compared nuclear factors identified in published HIV-1 proteomic studies and performed our own mass spectrometry analysis using affinity-tagged HIV-1 and RSV Gag proteins mixed with nuclear extracts. We identified 57 nuclear proteins in common between HIV-1 and RSV Gag, and a set of nuclear proteins present in our analysis and ≥ 1 of the published HIV-1 datasets. Many proteins were associated with nuclear processes which could have functional consequences for viral replication, including transcription initiation/elongation/termination, RNA processing, splicing, and chromatin remodeling. Examples include facilitating chromatin remodeling to expose the integrated provirus, promoting expression of viral genes, repressing the transcription of antagonistic cellular genes, preventing splicing of viral RNA, altering splicing of cellular RNAs, or influencing viral or host RNA folding or RNA nuclear export. Many proteins in our pulldowns common to RSV and HIV-1 Gag are critical for transcription, including PolR2B, the second largest subunit of RNA polymerase II (RNAPII), and LEO1, a PAF1C complex member that regulates transcriptional elongation, supporting the possibility that Gag influences the host transcription profile to aid the virus. Through the interaction of RSV and HIV-1 Gag with splicing-related proteins CBLL1, HNRNPH3, TRA2B, PTBP1 and U2AF1, we speculate that Gag could enhance unspliced viral RNA production for translation and packaging. To validate one putative hit, we demonstrated an interaction of RSV Gag with Mediator complex member Med26, required for RNA polymerase II-mediated transcription. Although 57 host proteins interacted with both Gag proteins, unique host proteins belonging to each interactome dataset were identified. These results provide a strong premise for future functional studies to investigate roles for these nuclear host factors that may have shared functions in the biology of both retroviruses, as well as functions specific to RSV and HIV-1, given their distinctive hosts and molecular pathology.Graphical

In silico analysis: Fulleropyrrolidine derivatives against HIV-PR mutants and SARS-CoV-2 Mpro

Abstract Approximately 37.9 million people living with HIV (PLWH) are at risk of severe consequences from COVID-19. Urgent development of tailored treatments for PLWH, who have historically been excluded from vaccine trials, is crucial. The present study introduces some modified fulleropyrrolidine derivatives with chalcogen atoms (O, S, or Se) and hydroxymethylcarbonyl (HMC) groups to target 11 single and double HIV-1 protease (HIV-PR) mutations and the main protease of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2 Mpro). The inhibitory activities of these derivatives are computationally examined through molecular docking, molecular dynamic simulations for 200 ns, and Lipinski’s rule of five (RO5). Fourier-transform infrared spectroscopy spectra and thermodynamic properties are calculated and analyzed using Density Functional Theory B88-PW91 method. The results indicate that the suggested O-compounds obey three parameters of the RO5 and HMC forms hydrogen bonds with studied viral proteases. Compounds with O and S additives display a high binding affinity with negative binding energy values for HIV-PR mutations (A71V-I84V, V77I-I84V, and I84V-L90M) and SARS-CoV-2 Mpro. The compounds with S and Se additives shift to lower frequencies of the major vibrational bands. Specifically, compound 1, with two oxygen additives, emerges as the most effective in inhibiting both HIV-PR mutations and SARS-CoV-2 Mpro.

Interaction of HIV-1 Gag matrix domain with plasma membrane from coarse-grained molecular dynamics simulations

We performed coarse-grained simulations with explicit solvent to analyse the role of myristoyl in the matrix domain of the HIV-1 protein Gag that interacts with three models of the lipid bilayer. These models were chosen to represent:(a) the inner membrane of the mammalian plasma membrane, (b) the lipid-raft domains, and (c) a generic cholesterol-free bilayer. The inner plasma membrane is the target for the Gag protein when forming the HIV-1 capsid. The other two models permit investigations of the effects of bilayer composition on the interaction between the matrix domain and the lipid bilayer. Our coarse-grained simulations allow sampling over several hundreds of microseconds, in contrast to other atomistic-detail simulations that can only cover a few microseconds. We measured the probability distributions associated with position and orientation of the myristoyl interacting with the plasma membrane models and quantified the orientational order of the myristoyl inserted into the membrane. We determined the Gibbs free energies (potentials of mean force and torque) associated with the observed probability distributions and determined binding energy values of the order of 8 kT , equivalent to ∼ 5 kcal mol − 1 at physiological temperature. Our methods can be applied to other acylated proteins interacting with the plasma membrane.

Analysis of Arc/Arg3.1 Oligomerization In Vitro and in Living Cells.

Arc (also known as Arg3.1) is an activity-dependent immediate early gene product enriched in neuronal dendrites. Arc plays essential roles in long-term potentiation, long-term depression, and synaptic scaling. Although its mechanisms of action in these forms of synaptic plasticity are not completely well established, the activities of Arc include the remodeling of the actin cytoskeleton, the facilitation of AMPA receptor (AMPAR) endocytosis, and the regulation of the transcription of AMPAR subunits. In addition, Arc has sequence and structural similarity to retroviral Gag proteins and self-associates into virus-like particles that encapsulate mRNA and perhaps other cargo for intercellular transport. Each of these activities is likely to be influenced by Arc's reversible self-association into multiple oligomeric species. Here, we used mass photometry to show that Arc exists predominantly as monomers, dimers, and trimers at approximately 20 nM concentration in vitro. Fluorescence fluctuation spectroscopy revealed that Arc is almost exclusively present as low-order (monomer to tetramer) oligomers in the cytoplasm of living cells, over a 200 nM to 5 μM concentration range. We also confirmed that an α-helical segment in the N-terminal domain contains essential determinants of Arc's self-association.

Surface functionalization of virus-like particles via bioorthogonal click reactions for enhanced cell-specific targeting

Surface functionalization of nano drug carriers allows for precise delivery of therapeutic molecules to the target site. This technique involves attaching targeting molecules to the nanoparticle surface, facilitating selective interaction. In this study, we engineered virus-like particles (VLPs) to enhance their targeting capabilities. Azide groups incorporated on the lipid membranes of VLPs enabled bioorthogonal click reactions for conjugation with cycloalkyne-bearing molecules, providing efficient conjugation with high specificity. HIV-1 Gag VLPs were chosen due to their envelope, which allows host membrane component incorporation, and the Gag protein, which serves as a recognition motif for human T cells. This combination, along with antibody-mediated targeting, addresses the limitations of intracellular delivery to T cells, which typically exhibit low uptake of exogenous materials. The selective uptake of azide VLPs by CD3-positive T cells was evaluated in a co-culture system. Even without antibody conjugation, VLP uptake was enhanced in T cells, indicating their intrinsic targeting potential. Antibody conjugation further amplified this effect, demonstrating the synergistic benefits of the combined targeting approach. Our study shows that recombinant production of azide functionalized VLPs results in engineered nanoparticles that can be easily modified using bioorthogonal click reactions, providing high specificity and versatility for conjugation with various molecules, making it applicable to a wide range of biological products.

Unveiling Novel HIV-1 Protease Inhibitors through an Integrated Analysis of 3D-QSAR, Molecular Docking, and Binding Free Energy

Introduction: HIV-1, the primary causative agent of AIDS, remains a formidable and lethal virus globally, claiming the lives of millions over the past four decades since its discovery. Recent research has underscored the potential of HIV-1 protease as a therapeutic target, offering a promising strategy for inhibiting viral replication within the body. Method: In light of this, we have curated an extensive database comprising 193 derivatives of Darunavir (DRV), an HIV-1 protease inhibitor. Simultaneously, we have developed a comprehensive set of 3D-QSAR models to elucidate the structure-activity relationships of these 193 derivative inhibitors. Employing various computational simulation techniques, including Comparative Molecular Field Analysis (CoMFA), Comparative Similarity Indices Analysis (CoMSIA), and molecular docking, we have unveiled the fundamental three-dimensional structural features influencing their biological activity. Result: Results indicate that the optimal CoMSIA model (Q2 = 0.500, R2 ncv = 0.882, R2 pred = 0.797) surpasses other models, demonstrating superior predictive capability. Furthermore, docking results suggest that DRV derivatives maintain stable conformations within the binding cavity due to synergistic interactions, such as hydrogen bonding and non-bonded interactions. Drawing insights from the best computational models, we have designed five DRV derivatives with significant HIV-1 protease inhibitory activity through local modification, with theoretical calculations indicating favorable pharmacokinetic properties and synthetic feasibility for the newly proposed molecules. Conclusion: It is hoped that the findings and conclusions obtained herein may furnish theoretical underpinning and directional guidance for the design, optimization, and experimental synthesis of DRV derivative compounds for pharmaceutical purposes. conclusion: In conclusion, this research identifies key residues, including Asp25, Gly27, Asp29, Asp30, Asp124, and Asp129, as significant for ligand binding. The information derived from the in silico models contributes to the design of five newly proposed DRV derivative compounds as promising HIV-1 protease inhibitors, surpassing the inhibitory activity of compound 171. The study holds potential for optimizing Darunavir derivatives in the development of anti-HIV-1 protease drugs.

Computational investigation of Y. aloifolia variegate as anti-Human Immunodeficiency Virus (HIV) targeting HIV-1 protease: A multiscale in-silico exploration

IntroductionHuman Immunodeficiency Virus (HIV) is a global challenge for the health sector due to the absence of a definitive cure. More than 38 million people are affected by the disease worldwide, with approximately 1.5 million new cases reported annually. This situation has spurred continued efforts in searching for drug candidates. Meanwhile, rutin, luteolin, and quercetin are compounds known for efficacy in treating infectious diseases. The compounds have also been detected in Yucca aloifolia (絲蘭) variegate L. Therefore, this study aimed to conduct a computational investigation utilizing multiscale in silico exploration to assess the potential of Y. aloifolia as an anti-HIV agent targeting HIV-1 Protease (H1P). MethodsFor the in silico study, the three-dimensional structure of H1P (PDB: 5V4Y) was retrieved and prepared using YASARA Structure. The binding pockets were identified using Cavity Plus server, and ligands were obtained from Y. aloifolia leaves alcohol extract. Furthermore, molecular docking was conducted with YASARA Structure to predict binding energies, followed by QSAR analysis for activity prediction. Density Functional Theory (DFT) analysis was performed to assess stability and reactivity, while toxicity was evaluated using ProTox 3.0. Molecular dynamics (MD) simulation and Molecular Mechanics Poisson–Boltzmann Surface Area (MM-PBSA) calculation were also conducted for further analysis. ResultsThe results showed that Ramachandran plot analysis indicated favorable residue distribution based on the evaluation of enzyme preparation quality. Cavity Plus identified potential binding sites, with cavity no.2 showing the highest druggability. Molecular docking showed rutin and isorhamnetin-3-O-rutinoside as top binders to H1P, with favorable binding energies. Moreover, post-docking analysis produced specific interactions between ligands and the receptor. PASS prediction indicated the potential of rutin and isorhamnetin-3-O-rutinoside (narcissin) as H1P inhibitors. DFT analysis assessed stability, showing comparable values for the investigated compounds. Toxicity analysis suggested both compounds to be non-toxic. Finally, MD simulation demonstrated the superior stability and binding affinity of rutin compared to isorhamnetin-3-O-rutinoside and the control drug, grl-09510. DiscussionRutin, hecogenin, and isorhamnetin-3-O-rutinoside from Y. aloifolia (絲蘭) leaves showed potential as H1P inhibitors through in silico study. Docking simulations indicated that rutin had the most favorable binding interactions, while MD simulation showed only the rutin-H1P complex to be stable, signifying the potential for further drug development. Rutin was identified as a promising lead for H1P inhibition due to its strong binding, stability, and predicted safety properties, underscoring the need for wet lab validation.

Description and In silico ADME Studies of US-FDA Approved Drugs or Drugs under Clinical Trial which Violate the Lipinski’s Rule of 5

Background &amp; Objective: Christopher A. Lipinski, in 1997, formulated Lipinski’s rule of five for drug-likeness prediction of potent molecules. It states that molecular weight (less than 500 Daltons), octanol/water partition coefficient (not exceeding more than 5), hydrogen bond acceptor (no more than 10), and hydrogen bond donor (no more than 5) are important for good oral bioavailability. Many drugs among various important classes such as antibiotics, anti-cancer, HIV and HCV protease inhibitors, immunosuppressants, cardiovascular, antifungal, and other miscellaneous classes are approved by FDA or other drug regulatory authorities as clinical use lie beyond the rule of five. In this review, beyond the rule of 5 drugs belonging to these classes (which are either currently approved or under clinical study) are explored and their ADME properties are analyzed. Methods: Data of 73 beyond the rule of 5 drugs, belonging to various classes, were collected and their ADME properties were calculated using the Qikprop prediction program of maestro 12.9 module of Schrodinger software. Result: Out of 73 drugs, 4 had at least 1 Rule of 5 (Ro5) violation, 16 had at least 2, 31 had at least 3 out of which 22 drugs had 4, Ro5 violations. Conclusion: Drugs not obeying the rule of five may also serve as good clinical candidates and potential candidates should not be discarded only on the basis of this rule.

Premature Activation of the HIV-1 Protease Is Influenced by Polymorphisms in the Hinge Region.

HIV-1 protease inhibitors are an essential component of antiretroviral therapy. However, drug resistance is a pervasive issue motivating a persistent search for novel therapies. Recent reports found that when protease activates within the host cell's cytosol, it facilitates the pyroptotic killing of infected cells. This has led to speculation that promoting protease activation, rather than inhibiting it, could help to eradicate infected cells and potentially cure HIV-1 infection. Here, we used a nanoscale flow cytometry-based assay to characterize protease resistance mutations and polymorphisms. We quantified protease activity, viral concentration, and premature protease activation and confirmed previous findings that major resistance mutations generally destabilize the protease structure. Intriguingly, we found evidence that common polymorphisms in the hinge domain of protease can influence its susceptibility to premature activation. This suggests that viral heterogeneity could pose a considerable challenge for therapeutic strategies aimed at inducing premature protease activation in the future.

Performance of the Applied Biosystems HIV-1 Genotyping Kit with Integrase.

HIV genotyping is used to assess HIV susceptibility to antiretroviral drugs. The Applied Biosystems HIV-1 Genotyping Kit with Integrase (AB kit, Thermo Fisher Scientific) detects resistance-associated mutations (RAMs) in HIV protease (PR), reverse transcriptase (RT), and integrase (IN). We compared results from the AB kit with results obtained previously with the ViroSeq HIV-1 Genotyping System. DNA amplicons from the AB kit were also analyzed using next-generation sequencing (NGS). HIV RNA was extracted using the MagNA Pure 24 instrument (Roche Diagnostics; 96 plasma samples, HIV subtype B, viral load range: 530-737,741 copies/mL). FASTA files were generated from AB kit data using Exatype (Hyrax Biosciences). DNA amplicons from the AB kit were also analyzed by NGS using the Nextera XT kit (Illumina). Drug resistance was predicted using the Stanford HIV Drug Resistance Database. The mean genetic distance for sequences from ViroSeq and the AB kit was 0.02% for PR/RT and 0.04% for IN; 103 major RAMs were detected by both methods. Four additional major RAMs were detected by the AB kit only. These four major RAMs were also detected by NGS (detected in 18.1%-38.2% of NGS reads). NGS detected 27 major RAMs that were not detected with either of the Sanger sequencing-based kits. All major RAMs detected with ViroSeq were detected with the AB kit; additional RAMs were detected with the AB kit only. DNA amplicons from the AB kit can be used for NGS for more sensitive detection of RAMs.

Changing selection on amino acid substitutions in Gag protein between major HIV-1 subtypes.

Amino acid preferences at a protein site depend on the role of this site in protein function and structure as well as on external constraints. All these factors can change in the course of evolution, making amino acid propensities of a site time-dependent. When viral subtypes divergently evolve in different host subpopulations, such changes may depend on genetic, medical, and sociocultural differences between these subpopulations. Here, using our previously developed phylogenetic approach, we describe sixty-nine amino acid sites of the Gag protein of human immunodeficiency virus type 1 (HIV-1) where amino acids have different impact on viral fitness in six major subtypes of the type M. These changes in preferences trigger adaptive evolution; indeed, 32 (46 per cent) of these sites experienced strong positive selection at least in one of the subtypes. At some of the sites, changes in amino acid preferences may be associated with differences in immune escape between subtypes. The prevalence of an amino acid in a protein site within a subtype is only a poor predictor for whether this amino acid is preferred in this subtype according to the phylogenetic analysis. Therefore, attempts to identify the factors of viral evolution from comparative genomics data should integrate across multiple sources of information.