HIV-1 Protease Research Articles

HIV-1 diverts cortical actin for particle assembly and release

Enveloped viruses assemble and bud from the host cell membranes. Any role of cortical actin in these processes have often been a source of debate. Here, we assessed if cortical actin was involved in HIV-1 assembly in infected CD4 T lymphocytes. Our results show that preventing actin branching not only increases HIV-1 particle release but also the number of individual HIV-1 Gag assembly clusters at the T cell plasma membrane. Indeed, in infected T lymphocytes and in in vitro quantitative model systems, we show that HIV-1 Gag protein prefers areas deficient in F-actin for assembling. Finally, we found that the host factor Arpin, an inhibitor of Arp2/3 branched actin, is recruited at the membrane of infected T cells and it can associate with the viral Gag protein. Altogether, our data show that, for virus assembly and particle release, HIV-1 prefers low density of cortical actin and may favor local actin debranching by subverting Arpin.

HTLV-1 biofilm polarization maintained by tetraspanin CD82 is required for efficient viral transmission.

In the early stages of infection, human T-lymphotropic virus type 1 (HTLV-1) dissemination within its host is believed to rely mostly on cell-to-cell contacts. Past studies unveiled a novel mechanism of HTLV-1 intercellular transmission based on the remodeling of the host-cell extracellular matrix and the generation of cell-surface viral assemblies whose structure, composition, and function resemble bacterial biofilms. These polarized aggregates of infectious virions, identified as viral biofilms, allow the bulk delivery of viruses to target cells and may help to protect virions from immune attacks. However, viral biofilms' molecular and functional description is still in its infancy, although it is crucial to fully decipher retrovirus pathogenesis. Here, we explore the function of cellular tetraspanins (CD9, CD81, CD82) that we detect inside HTLV-1 particles within biofilms. Our results demonstrate specific roles for CD82 in the cell-surface distribution and intercellular transmission of HTLV-1 biofilms, which we document as two essential parameters for efficient viral transmission. At last, our findings indicate that N-glycosylation of cell-surface molecules, including CD82, is required for the polarization of HTLV-1 biofilms and for the efficient transmission of HTLV-1 between T-lymphocytes.

Efficacy/Safety of the Use of Glucocorticoids in Oral and Maxillofacial Surgery.

Glucocorticoids, also known as corticosteroids or steroids, are drugs derived from cholesterol. They are synthesized by the adrenal cortex, along with other hormones, such as cortisol and aldosterone. Glucocorticoids are drugs recommended for patients undergoing surgery on the oral cavity, facial skeleton, and related cervical structures due to their high efficacy against inflammatory and immune processes. However, these drugs are restricted due to their multiple and serious adverse effects. The objective of this study was to verify the efficacy of corticosteroids administered in major surgeries of the oral cavity, as well as of the cervical and facial structures, based on the characteristics of the patient so as to select the best therapeutic strategy. Articles in the databases of PubMed, Nature Portfolio, Medline, Cochrane Library, and Google Scholar were thoroughly examined. A total of 54 articles were selected to address the proposed objectives. The results obtained show that it is effective and safe to use glucocorticoids as pre- or postsurgical therapy in oral and maxillofacial surgery to control the processes of inflammation, pain, lockjaw, and edema. However, when referring to the use of these drugs, one must proceed with caution and pay particular attention when handling them. The concentration of the glucocorticoids used must be individualized, as well as the selection of the route of administration. Various studies show that, although the oral route is the most used route, the most effective route is the intramuscular route due to its easy absorption. However, for patients who have recurrent inflammatory and vesiculobullous ulcerative lesions, the topical route should be chosen to mitigate side effects, considering that recurrent applications must be made to prevent the worsening of the lesion and to avoid having to use medications enterally. In patients with cervicofacial infections, antibiotics continue to be the main drugs used to manage the condition in conjunction with corticosteroids. It is important to know the possible interactions of glucocorticoids with other medicines or food: it has been described that the interaction between Ritonavir, an antiretroviral drug that inhibits human immunodeficiency virus (HIV) proteases, and prednisone causes an increase in the concentration of prednisone, leading to possible toxicity in normally safe doses and, in many cases, iatrogenic Cushing's syndrome. It is also important to know the systemic or topical adverse effects of the chronic or high-dose use of glucocorticoids. It can be concluded that by making adequate use of glucocorticoid therapy in oral and maxillofacial surgery to manage clinical manifestations, it is possible to attenuate the morbidities of treatment and intervention.

Novel wild type and mutate HIV-1 protease inhibitors containing heteroaryl carboxamides in P2: Synthesis, biological evaluations and in silico ADME prediction

The Virus HIV-1 infection still represents a serious disease even if actually it is transformed in chronic pathology. Considering the crucial role of the enzyme Protease in life cycle of HIV many efforts have been made in the research of new organic compounds showing inhibitory activity. After development of several series of non peptidic inhibitors we report here the synthesis of novel simple HIV-Protease inhibitors containing heteroaryl carboxamides and their antiviral activity in vitro and in HEK293 cells. Benzofuryl- benzothienyl- and indolyl rings as well as aryl sulfonamides with different electronic properties have been introduced by efficient synthetic procedures. All compounds showed inhibitory activity similar to the commercial drug Darunavir, effective against both wild-type HIV-1 protease and that containing the V32I or V82A mutations. Absorption, distribution, metabolism, excretion (ADME) properties were also evaluated in silico, showing the potential of such compounds to be developed as drugs.

Synthesis and Antiviral and Antitumor Activities of Novel 18β-Glycyrrhetinic Acid Derivatives.

A series of novel derivatives of 18β-glycyrrhetinic acid (GA) were synthesized by introducing aromatic or heterocyclic structures to extend the side chain, thereby enhancing their interaction with amino acid residues in the active pocket of the target protein. These compounds were structurally characterized using 1H NMR, 13C NMR, and HRMS. The compounds were subsequently evaluated for their inhibitory effects on HIV-1 protease and cell viability in the human cancer cell lines K562 and HeLa and the mouse cancer cell line CT26. Towards HIV-1 protease, compounds 28 and 32, which featured the introduction of heterocyclic moieties at the C3 position of GA, exhibited the highest inhibition, with inhibition rates of 76% and 70.5%, respectively, at 1 mg/mL concentration. Further molecular docking suggests that a 3-substituted polar moiety would be likely to enhance the inhibitory activity against HIV-1 protease. As for the anti-proliferative activities of the GA derivatives, incorporation of a thiazole heterocycle at the C3- position in compound 29 significantly enhanced the effect against K562 cells with an IC50 value of 8.86 ± 0.93 µM. The introduction of electron-withdrawing substituents on the C3-substituted phenyl ring augmented the anti-proliferative activity against Hela and CT26 cells. Compound 13 exhibited the highest inhibitory activity against Hela cells with an IC50 value of 9.89 ± 0.86 µM, whereas compound 7 exerted the strongest inhibition against CT26 cells with an IC50 value of 4.54 ± 0.37 µM. These findings suggest that further modification of GA is a promising path for developing potent novel anti-HIV and anticancer therapeutics.

Targeting PRSS23 with tipranavir induces gastric cancer stem cell apoptosis and inhibits growth of gastric cancer via the MKK3/p38 MAPK-IL24 pathway.

Gastric cancer stem cells (GCSCs) contribute to the refractory features of gastric cancer (GC) and are responsible for metastasis, relapse, and drug resistance. The key factors drive GCSC function and affect the clinical outcome of GC patients remain poorly understood. PRSS23 is a novel serine protease that is significantly up-regulated in several types of cancers and cancer stem cells, and related to tumor progression and drug resistance. In this study, we investigated the role of PRSS23 in GCSCs as well as the mechanism by which PRSS23 regulated the GCSC functions. We demonstrated that PRSS23 was critical for sustaining GCSC survival. By screening a collection of human immunodeficiency virus (HIV) protease inhibitors (PIs), we identified tipranavir as a PRSS23-targeting drug, which effectively killed both GCSC and GC cell lines (its IC50 values were 4.7 and 6.4 μM in GCSC1 cells and GCSC2 cells, respectively). Administration of tipranavir (25 mg·kg-1·d-1, i.p., for 8 days) in GCSC-derived xenograft mice markedly inhibited the growth of subcutaneous GCSC tumors without apparent toxicity. In contrast, combined treatment with 5-FU plus cisplatin did not affect the tumor growth but causing significant weight loss. Furthermore, we revealed that tipranavir induced GCSC cell apoptosis by suppressing PRSS23 expression, releasing MKK3 from the PRSS23/MKK3 complex to activate p38 MAPK, and thereby activating the IL24-mediated Bax/Bak mitochondrial apoptotic pathway. In addition, tipranavir was found to kill other types of cancer cell lines and drug-resistant cell lines. Collectively, this study demonstrates that by targeting both GCSCs and GC cells, tipranavir is a promising anti-cancer drug, and the clinical development of tipranavir or other drugs specifically targeting the PRSS23/MKK3/p38MAPK-IL24 mitochondrial apoptotic pathway may offer an effective approach to combat gastric and other cancers.

In silico discovery of epitopes of gag and env proteins for the development of a multi-epitope vaccine candidate against Maedi Visna Virus using reverse vaccinology approach

Maedi Visna Virus (MVV) causes a chronic viral disease in sheep. Since there is no specific therapeutic drug that targets MVV, development of a vaccine against the MVV is inevitable. This study aimed to analyze the gag and env proteins as vaccine candidate proteins and to identify epitopes in these proteins. In addition, it was aimed to construct a multi-epitope vaccine candidate. According to the obtained results, the gag protein was detected to be more conserved and had a higher antigenicity value. Also, the number of alpha helix in the secondary structure was higher and transmembrane helices were not detected. Although many B cell and MHC-I/II epitopes were predicted, only 19 of them were detected to have the properties of antigenic, non-allergenic, non-toxic, soluble, and non-hemolytic. Of these epitopes, five were remarkable due to having the highest antigenicity value. However, the final multi-epitope vaccine was constructed with 19 epitopes. A strong affinity was shown between the final multi-epitope vaccine and TLR-2/4. In conclusion, the gag protein was a better antigen. However, both proteins had epitopes with high antigenicity value. Also, the final multi-epitope vaccine construct had a potential to be used as a peptide vaccine due to its immuno-informatics results.

Characterization of bovine immunodeficiency virus genes and proteins

The goal of the study was determining the effect of natural selection on the bovine immunodeficiency virus (BIV) through the identification of polymorphisms by comparing a number of genes, open reading frames and proteins and analyzing the effect of nonsynonymous substitutions in the Vif protein of BIV isolates on the Vif conformational parameters. The selection pressure on the genes was estimated by Tajima test, as well as the determination of the ratio of nonsynonymous substitutions (Ka) to synonymous (Ks) Ka/Ks. Ka and Ks coefficients, their ratio (Ka/Ks) were calculated on the basis of alignments of amino acid and nucleotide sequences of the vif gene of BIV isolates. The nonsynonymous (dN) to synonymous (dS) substitution rate ratio per nucleotide site dN/dS was calculated to estimate the effect of selection on the vif gene by SLAC method on Datamonkey server. The number of hydrogen bonds, α-helices, β-sheets, β-turns for the protein tertiary structures of proteins was determined by I-TASSER server. Genes, open reading frames (ORFs) and the U3 regulatory region of BIV genome which are under the influence of selection have been identified. Gag, pol, s, vif genes, ORF W and ORF Y are under the negative (purifying) selection pressure. Env gene and the U3 regulatory region are under positive selection. Shannon entropy analysis (peaks that are specific to the positions of amino acid residues), interpreted as polymorphisms, revealed 16, 8, and 4 nonsynonymous substitutions for Pol, Gag, and Vif BIV proteins, respectively. Significant changes in the number of hydrogen bonds, α-helices, β-layers, β-turns were determined by the analysis of the effect of four nonsynonymous substitutions in the Vif protein on the conformational parameters of Vif of two BIV isolates. The multidirectional effect of selection on BIV genes is shown

A Combination of Novel HIV-1 Protease Inhibitor and Cytochrome P450 (CYP) Enzyme Inhibitor to Explore the Future Prospective of Antiviral Agents: Evotaz.

Viruses belong to the class of micro-organisms that are well known for causing infections in the human body. Antiviral medications are given out to prevent the spread of disease-causing viruses. When the viruses are actively reproducing, these agents have their greatest impact. It is particularly challenging to develop virus-specific medications since viruses share the majority of the metabolic functions of the host cell. In the continuous search for better antiviral agents, the United States Food and Drug Administration (USFDA) approved a new drug named Evotaz on January 29, 2015 for the treatment of human immunodeficiency virus (HIV). Evotaz is a combined once-daily fixed drug, containing Atazanavir, an HIV protease inhibitor, and cobicistat, an inhibitor of the human liver cytochrome P450 (CYP) enzyme. The medication is created such that it can kill viruses by concurrently inhibiting protease and CYP enzymes. The medicine is still being studied for a number of criteria, but its usefulness in children under the age of 12 is currently unknown. The preclinical and clinical characteristics of Evotaz, as well as its safety and efficacy profiles and a comparison of the novel drug with antiviral medications presently available in the market, are the main topics of this review paper.

Machine-learning-based virtual screening and ligand docking identify potent HIV-1 protease inhibitors

The human immunodeficiency virus type 1 (HIV-1) is a retrovirus that can cause acquired immunodeficiency syndrome (AIDS), severely weakening the immune system. The United Nations estimates that there are 37.7 million people with HIV worldwide. HIV-1 protease (PR) cleaves polyproteins to create the individual proteins that comprise an HIV virion. Inhibiting PR prevents the creation of new virions, rendering PR an attractive antiviral target. In the present study, a machine-learning regression model was constructed to predict pIC50 bioactivity concentrations using data from 2547 experimentally characterized PR inhibitors. The model achieved Pearson correlation coefficient of 0.88, R-squared of 0.78, and a RMSE of 0.717 in pIC50 units on unseen data using 199 high-variance PubChem substructure fingerprints. The SWEETLEAD database of approximately 4300 traditional medicine compounds and drugs from around the world was screened using the model. Fifty molecules were identified as highly potent, with pIC50 of at least 7.301 (IC50 <= 50 nM). Nine of these molecules, such as lopinavir and ritonavir, are known antiviral drugs. The highly potent molecules were ligand-docked to the 3D structure of HIV protease at the active site. Dihydroergotamine mesylate (daechu alkaloids) had a very strong binding affinity of −13.2, outperforming all known antiviral drugs that were tested. It was also predicted by the model to have an IC50 of 9.16 nM, which is considered very low and desirable. Overall, this study demonstrates the use of machine-learning regression models for virtual screening and highlights several drugs with significant promise for repurposing against HIV-1. Future steps include testing dihydroergotamine mesylate and other candidates in vitro.

An active HIV reservoir during ART is associated with maintenance of HIV-specific CD8+ T cell magnitude and short-lived differentiation status

Before initiation of antiretroviral therapy (ART), HIV-specific CD8+ Tcells are dysfunctional and short lived. To better understand the relationship between the HIV reservoir in CD4+ Tcells and the magnitude and differentiation status of HIV-specific CD8+ Tcells, we investigated these cells from acute and chronic HIV-infected individuals after 2 years of ART. Although both the HIV reservoir and the CD8+ Tcell responses declined significantly after 2 years of ART, sustained HIV-specific CD8+ Tcell responses correlated with a greater reduction of integrated HIV provirus. However, the magnitude of CD8+ Tcells specific for HIV Gag, Pol, Nef, and Vif proteins positively associated with the active reservoir size during ART, measured as cell-associated RNA. Importantly, high HIV DNA levels strongly associate with maintenance of short-lived HIV-specific CD8+ Tcells, regardless of ART initiation time. Our data suggest that the active reservoir maintains HIV-specific CD8+ Tcell magnitude but prevents their differentiation into functional cells.

Dynamozones are the most obvious sign of the evolution of conformational dynamics in HIV-1 protease

Proteins are not static but are flexible molecules that can adopt many different conformations. The HIV-1 protease is an important target for the development of therapies to treat AIDS, due to its critical role in the viral life cycle. We investigated several dynamics studies on the HIV-1 protease families to illustrate the significance of examining the dynamic behaviors and molecular motions for an entire understanding of their dynamics-structure–function relationships. Using computer simulations and principal component analysis approaches, the dynamics data obtained revealed that: (i) The flap regions are the most obvious sign of the evolution of conformational dynamics in HIV-1 protease; (ii) There are dynamic structural regions in some proteins that contribute to the biological function and allostery of proteins via appropriate flexibility. These regions are a clear sign of the evolution of conformational dynamics of proteins, which we call dynamozones. The flap regions are one of the most important dynamozones members that are critical for HIV-1 protease function. Due to the existence of other members of dynamozones in different proteins, we propose to consider dynamozones as a footprint of the evolution of the conformational dynamics of proteins.

Drug Reprofiling to Identify Potential HIV-1 Protease Inhibitors.

The use of protease inhibitors in human immunodeficiency virus type 1 (HIV-1) treatment is limited by adverse effects, including metabolic complications. To address these challenges, efforts are underway in the pursuit of more potent and less toxic HIV-1 protease inhibitors. Repurposing existing drugs offers a promising avenue to expedite the drug discovery process, saving both time and costs compared to conventional de novo drug development. This study screened FDA-approved and investigational drugs in the DrugBank database for their potential as HIV-1 protease inhibitors. Molecular docking studies and cell-based assays, including anti-HIV-1 in vitro assays and XTT cell viability tests, were conducted to evaluate their efficacy. The study findings revealed that CBR003PS, an antibiotic currently in clinical use, and CBR013PS, an investigational drug for treating endometriosis and uterine fibroids, exhibited significant binding affinity to the HIV-1 protease with high stability. Their EC50 values, measured at 100% cell viability, were 9.4 nM and 36.6 nM, respectively. Furthermore, cell-based assays demonstrated that these two compounds showed promising results, with therapeutic indexes higher than 32. In summary, based on their favorable therapeutic indexes, CBR003PS and CBR013PS show potential for repurposing as HIV-1 protease inhibitors.

Hsa-miR-181-5p inhibits human immunodeficiency virus type 1 replication by downregulating DDX3X expression

BackgroundHIV-1 infection affects expression profiles of microRNA. miR-181 is found negatively correlated with HIV-1 viral load. This study aimed to explain that miR-181 targets DDX3X, a host factor involved in HIV-1 nuclear export, thereby inhibiting HIV-1 replication. MethodsTo verify our hypothesis, first, the relationship between miR-181 expression, DDX3X expression, and HIV-1 viral load was analyzed. Second, miR-181 mimics were transfected into Jurkat cells infected with wild pNL4-3 strain or H9-IIIB cells with HIV-1 replication-competent for HIV-1 viral protein P24(Gag) detection. Besides the reporter gene plasmid containing the DDX3X mRNA sequence was transfected into 293T cells to demonstrate the targeting of miR-181 to the DDX3X mRNA. Finally, the spliced, unspliced, or incompletely spliced HIV-1 transcripts and HIV-1 Tat, Rev, and Gag mRNA were also detected after miR-181 transfection. ResultsOur result proved that miR-181 significantly reduced the HIV-1 viral protein Gag(P24) level and targeted DDX3X mRNA 3′-UTR, inhibiting the unspliced or incompletely spliced HIV-1 mRNA's nuclear export. ConclusionOur results confirmed that miR-181 is involved in HIV-1 viral replication in lymphocytes by downregulating DDX3X expression. The research provides a research basis for future HIV-1 antiviral research.

Evolution of drug resistance drives destabilization of flap region dynamics in HIV-1 protease

The HIV-1 protease is one of several common key targets of combination drug therapies for human immunodeficiency virus infection and acquired immunodeficiency syndrome. During the progression of the disease, some individual patients acquire drug resistance due to mutational hotspots on the viral proteins targeted by combination drug therapies. It has recently been discovered that drug-resistant mutations accumulate on the “flap region” of the HIV-1 protease, which is a critical dynamic region involved in nonspecific polypeptide binding during invasion and infection of the host cell. In this study, we utilize machine learning-assisted comparative molecular dynamics, conducted at single amino acid site resolution, to investigate the dynamic changes that occur during functional dimerization and drug binding of wild-type and common drug-resistant versions of the main protease. We also use a multiagent machine learning model to identify conserved dynamics of the HIV-1 main protease that are preserved across simian and feline protease orthologs. We find that a key conserved functional site in the flap region, a solvent-exposed isoleucine (Ile50) that controls flap dynamics is functionally targeted by drug resistance mutations, leading to amplified molecular dynamics affecting the functional ability of the flap region to hold the drugs. We conclude that better long-term patient outcomes may be achieved by designing drugs that target protease regions that are less dependent upon single sites with large functional binding effects.

A multi-layer photonic spiking neural network with a modified backpropagation algorithm for nonlinear classification

In this work, we construct a fully connected multi-layer photonic spiking neural network (PSNN) based on excitable vertical-cavity surface-emitting lasers with an embedded saturable absorber (VCSELs-SA) equipped with the modified supervised backpropagation (BP) algorithm. Different from the traditional BP algorithm, our proposed modified BP algorithm is based on optical spikes, and its activation function exploits the excitable characteristic of VCSELs-SA. It is demonstrated that this BP PSNN can be competent in linearly inseparable problems by correctly solving the exclusive or (XOR) problem. Thus, a three-layer fully connected BP PSNN is designed to perform the prediction of Human immunodeficiency virus-1 protease (HIV-1 PR) cleavage sites and achieves 91.95% classification accuracy with the modified BP algorithm, which could be a useful tool in helping to find effective inhibitors of HIV PR to fight against acquired immunodeficiency syndrome (AIDS). These results demonstrate the validity of our modified BP algorithm in dealing with nonlinear classification problems in PSNNs, which is helpful for supervised learning in the photonic neuromorphic computing architecture for future neuromorphic applications.

Potentially Highly Effective Drugs for COVID-19: Virtual Screening and Molecular Docking Study Through PyRx-Vina Approach

Introduction: The World Health Organization (WHO) has declared the novel coronavirus (COVID-2019) infection outbreak a global health emergency. Drug repurposing, which concerns the investigation of existing drugs for new therapeutic target indications, has emerged as a successful strategy for drug discovery due to the reduced costs and expedited approval procedures.Material and Methods: The crystal structure of a protein essential for virus replication has been filed in the Protein Data Bank recently. Based on this structure and existing experimental datasets for SARS-CoV2(COVID-19) we present results deriving from the virtual screening of a database of more than 1000 drugs in the DrugBank that have been approved by Food and Drug Administration (FDA).Results: Results showed that some of the known protease inhibitors currently used in HIV and Cancer infections might be helpful for the therapy of COVID-19 also. Results also showed that Levomefolic acid, or vitamin B9, is recommended therapy because of its oral sources and no side effects.Conclusion: Between all studied FDA-approved drug, VitaminB9 and Etoposide which used for HIV protease inhibitor, revealed strong interaction with protease binding pocket and placed well into the pocket even better than the lopinavir-ritonavir, and since this compound is FDA-approved and successfully passed various testing steps, therefor there is a hope that this drug, could be a potential drug to treating the COVID-19.

HIV protease inhibitor saquinavir inhibits toll-like receptor 4 activation by targeting receptor dimerization

ObjectiveToll-like receptor 4 (TLR4) is crucial in induction of innate immune response through recognition of invading pathogens or endogenous alarming molecules. Ligand-triggered dimerization of TLR4 is essential for the activation of NF-κB and IRF3 through MyD88- or TRIF-dependent pathways. Saquinavir (SQV), an FDA-approved HIV protease inhibitor, has been shown to attenuate the activation of NF-κB induced by HMGB1 by blocking TLR4-MyD88 association in proteasome independent pathway. This study aims to define whether SQV is an HMGB1-specific and MyD88-dependent TLR4 signaling inhibitor and which precise signaling element of TLR4 is targeted by SQV.Materials and methodsPMA differentiated human THP-1 macrophages or reconstituted HEK293 cells were pretreated with SQV before stimulated by different TLR agonists. TNF-α level was evaluated through ELISA assay. NF-κB activation was analyzed using NF-κB SEAP reporting system. The levels of MyD88/TRIF pathways-related factors were examined by immunoblot. TLR4 endocytosis was assessed by immunocytochemistry. TLR4 dimerization was determined using immunoprecipitation between different tagged TLR4 and an in silico molecular docking experiment was performed to explore the possible binding site of SQV on its target.ResultsOur data showed that SQV suppresses both MyD88- and TRIF-dependent pathways in response to lipopolysaccharide (LPS), a critical sepsis inducer and TLR4 agonist, leading to downregulation of NF-κB and IRF3. SQV did not suppress MyD88-dependent pathway triggered by TLR1/2 agonist Pam3csk4. In the only TRIF-dependent pathway, SQV did not alleviate IRF3 phosphorylation induced by TLR3 agonist Poly(I:C). Furthermore, dimerization of TLR4 following LPS or HMGB1 stimulation was decreased by SQV.ConclusionWe concluded that TLR4 receptor complex is one of the mammalian targets of SQV, and TLR4-mediated immune responses and consequent risk for uncontrolled inflammation could be modulated by FDA-approved drug SQV.

Withania somnifera extracts induced attenuation of HIV-1: a mechanistic approach to restrict viral infection

BackgroundSeveral anti-retroviral drugs are available against Human immunodeficiency virus type-1, but have multiple adverse side effects. Hence, there is an incessant compulsion for effectual anti-retroviral agents with minimal or no intricacy. Traditionally, natural products have been the most successful source for the development of new medications. Withania somnifera, also known as Ashwagandha, is the utmost treasured medicinal plant used in Ayurveda, which holds the potential to give adaptogenic, immunomodulatory, and antiviral effects. However, its effect on HIV-1 replication at the cellular level has never been explored. Herein, we focused on the anti-HIV-1 activity and the probable mechanism of action of hydroalcoholic and aqueous extracts of Withania somnifera roots and its phytomolecules.MethodsThe cytotoxicity of the extracts was determined through MTT assay, while the in vitro anti-HIV-1 activity was assessed in TZM-bl cells against the HIV-1 strains of X4 and R5 subtypes. Results were confirmed in peripheral blood mononuclear cells, using the HIV-1 p24 antigen assay. Additionally, the mechanism of action was determined through the Time of Addition assay, which was further validated through the series of enzymatic assays, i.e. HIV-1 Integrase, Reverse transcriptase, and Protease assays. To explore the role of the identified active metabolites of Withania somnifera in antiretroviral activity, molecular docking analyses were performed against these key HIV-1 replication enzymes.ResultsThe hydroalcoholic and aqueous extracts of Withania somnifera roots were found to be safer at the sub-cytotoxic concentrations and exhibited their ability to inhibit replication of two primary isolates of HIV-1 through cell-associated and cell-free assays, in dose-dependent kinetics. Several active phytomolecules found in Withania somnifera successfully established hydrogens bonds in the active binding pocket site residues responsible for the catalytic activity of HIV replication and therefore, signifying their role in the attenuation of HIV-1 infection as implied through the in silico molecular docking studies.ConclusionsOur research identified both the hydroalcoholic and aqueous extracts of Withania somnifera roots as potent inhibitors of HIV-1 infection. The in silico analyses also indicated the key components of Withania somnifera with the highest binding affinity against the HIV-1 Integrase by 12-Deoxywithastramonolide and 27-Hydroxywithanone, HIV-1 Protease by Ashwagandhanolide and Withacoagin, and HIV-1 Reverse transcriptase by Ashwagandhanolide and Withanolide B, thereby showing possible mechanisms of HIV-1 extenuation. Overall, this study classified the role of Withania somnifera extracts and their active compounds as potential agents against HIV-1 infection.

Antiviral activity and active components of the leaves from Sabia parviflora Wall. ex Roxb

Sabia parviflora ( SP , “xiao hua qing feng teng” in Chinese) was recorded as an important ethnic medicine to be used for treating viral hepatitis. The antiviral activity of four SP extracts and potent antiviral compounds evaluated with cathepsin L protease (Cat L PR) and HIV-1 protease (HIV-1 PR). UPLC-HRMS was used for identifying the bioactive components. In addition, the possible inhibitory mechanism of the identified compounds on viral protease was further discussed by molecular docking. As a result, four extracts of SP exhibited inhibitory activity of HIV-1 PR and Cat L PR with IC50 range from 0.015 to 0.80 mg/mL. Meanwhile, six compounds inhibited HIV-1 PR with IC50 range from 0.032 to 0.80 mg/mL. Moreover, procyanidin B2 had good affinity for HIV-1 PR and CatL PR protein, respectively. These findings suggest S. parviflora leaves can be used for treating HIV and procyanidin B2 may play a role in antiviral protease.