Project description:Dendritic cells (DCs) efficiently transfer captured (trans) or de novo-produced (cis) virus to CD4 T cells. Using monocyte-derived DCs, we evaluated entry inhibitors targeting HIV envelope (BMS-C, T-1249) or CCR5 (CMPD167) for their potency to prevent DC infection, DC-driven infection in T cells in trans and cis, and direct infection of DC-T-cell mixtures. Immature DC-T-cell cultures with distinct mechanisms of viral transfer yielded similar levels of infection and produced more proviral DNA compared with matched mature DC-T-cell cultures or infected immature DCs. Although all compounds completely blocked HIV replication, 16 times more of each inhibitor (250 vs 15.6 nM) was required to prevent low-level infection of DCs compared with the productive DC-T-cell cocultures. Across all cell systems tested, BMS-C blocked infection most potently. BMS-C was significantly more effective than CMPD167 at preventing DC infection. In fact, low doses of CMPD167 significantly enhanced DC infection. Elevated levels of CCL4 were observed when immature DCs were cultured with CMPD167. Viral entry inhibitors did not interfere with Candida albicans-specific DC cytokine/chemokine responses. These findings indicate that an envelope-binding small molecule is a promising tool for topical microbicide design to prevent the infection of early targets needed to establish and disseminate HIV infection.
Project description:Our previous studies have shown that cholesterol-conjugated, peptide-based pan-coronavirus (CoV) fusion inhibitors can potently inhibit human CoV infection. However, only palmitic acid (C16)-based lipopeptide drugs have been tested clinically, suggesting that the development of C16-based lipopeptide drugs is feasible. Here, we designed and synthesized a C16-modified pan-CoV fusion inhibitor, EK1-C16, and found that it potently inhibited infection by SARS-CoV-2 and its variants of concern (VOCs), including Omicron, and other human CoVs and bat SARS-related CoVs (SARSr-CoVs). These results suggest that EK1-C16 could be further developed for clinical use to prevent and treat infection by the currently circulating MERS-CoV, SARS-CoV-2 and its VOCs, as well as any future emerging or re-emerging coronaviruses.
Project description:IntroductionThe COVID-19 global epidemic caused by severe acute respiratory syndrome coronavirus (SARS-CoV-2) is a great public health emergency. Discovering antiviral drug candidates is urgent for the prevention and treatment of COVID-19.ObjectivesThis work aims to discover natural SARS-CoV-2 inhibitors from the traditional Chinese herbal medicine licorice.MethodsWe screened 125 small molecules from Glycyrrhiza uralensis Fisch. (licorice, Gan-Cao) by virtual ligand screening targeting the receptor-binding domain (RBD) of SARS-CoV-2 spike protein. Potential hit compounds were further evaluated by ELISA, SPR, luciferase assay, antiviral assay and pharmacokinetic study.ResultsThe triterpenoids licorice-saponin A3 (A3) and glycyrrhetinic acid (GA) could potently inhibit SARS-CoV-2 infection, with EC50 of 75 nM and 3.17 µM, respectively. Moreover, we reveal that A3 mainly targets the nsp7 protein, and GA binds to the spike protein RBD of SARS-CoV-2.ConclusionIn this work, we found GA and A3 from licorice potently inhibit SARS-CoV-2 infection by affecting entry and replication of the virus. Our findings indicate that these triterpenoids may contribute to the clinical efficacy of licorice for COVID-19 and could be promising candidates for antiviral drug development.
Project description:Ebola virus disease is a severe disease caused by highly pathogenic Ebolaviruses. Although it shows a high mortality rate in humans, currently there is no licensed therapeutic. During the recent epidemic in West Africa, it was demonstrated that administration of antimalarial medication containing amodiaquine significantly lowered mortality rate of patients infected with the virus. Here, in order to improve its antiviral activity, a series of amodiaquine derivatives were synthesized and tested for Ebola virus infection. We found that multiple compounds were more potent than amodiaquine. The structure-activity relationship analysis revealed that the two independent parts, which are the alkyl chains extending from the aminomethyl group and a halogen bonded to the quinoline ring, were keys for enhancing antiviral potency without increasing toxicity. When these modifications were combined, the antiviral efficacy could be further improved with the selectivity indexes being over 10-times higher than amodiaquine. Mechanistic evaluation demonstrated that the potent derivatives blocked host cell entry of Ebola virus, like the parental amodiaquine. Taken together, our work identified novel potent amodiaquine derivatives, which will aid in further development of effective antiviral therapeutics.
Project description:BackgroundNonnucleoside reverse transcriptase inhibitors (NNRTIs) are a class of antiretroviral compounds that bind in an allosteric binding pocket in HIV-1 RT, located about 10 Å from the polymerase active site. Binding of an NNRTI causes structural changes that perturb the alignment of the primer terminus and polymerase active site, preventing viral DNA synthesis. Rilpivirine (RPV) is the most recent NNRTI approved by the FDA, but like all other HIV-1 drugs, suboptimal treatment can lead to the development of resistance. To generate better compounds that could be added to the current HIV-1 drug armamentarium, we have developed several RPV analogs to combat viral variants that are resistant to the available NNRTIs.ResultsUsing a single-round infection assay, we identified several RPV analogs that potently inhibited a broad panel of NNRTI resistant mutants. Additionally, we determined that several resistant mutants selected by either RPV or Doravirine (DOR) caused only a small increase in susceptibility to the most promising RPV analogs.ConclusionsThe antiviral data suggested that there are RPV analogs that could be candidates for further development as NNRTIs, and one of the most promising compounds was modeled in the NNRTI binding pocket. This model can be used to explain why this compound is broadly effective against the panel of NNRTI resistance mutants.
Project description:COVID-19 caused by SARS-CoV-2 has posed a significant threat to global public health since its outbreak in late 2019. Although there are a few drugs approved for clinical treatment to combat SARS-CoV-2 infection currently, the severity of the ongoing global pandemic still urges the efforts to discover new antiviral compounds. As the viral spike (S) protein plays a key role in mediating virus entry, it becomes a potential target for the design of antiviral drugs against COVID-19. Here, we tested the antiviral activity of berbamine hydrochloride, a bis-benzylisoquinoline alkaloid, against SARS-CoV-2 infection. We found that berbamine hydrochloride could efficiently inhibit SARS-CoV-2 infection in different cell lines. Further experiments showed berbamine hydrochloride inhibits SARS-CoV-2 infection by targeting the viral entry into host cells. Moreover, berbamine hydrochloride and other bis-benzylisoquinoline alkaloids could potently inhibit S-mediated cell-cell fusion. Furthermore, molecular docking results implied that the berbamine hydrochloride could bind to the post fusion core of SARS-CoV-2 S2 subunit. Therefore, berbamine hydrochloride may represent a potential efficient antiviral agent against SARS-CoV-2 infection.
Project description:Integrase strand transfer inhibitors (INSTIs) are a class of antiretroviral compounds that prevent the insertion of a DNA copy of the viral genome into the host genome by targeting the viral enzyme integrase (IN). Dolutegravir (DTG) is a leading INSTI that is given, usually in combination with nucleoside reverse transcriptase inhibitors (NRTIs), to treat HIV-1 infections. The emergence of resistance to DTG and other leading INSTIs is rare. However, there are recent reports suggesting that drug resistance mutations can occur at positions outside the integrase gene either in the HIV-1 polypurine tract (PPT) or in the envelope gene (env). Here, we used single round infectivity assays to measure the antiviral potencies of several FDA-approved INSTIs and non-nucleoside reverse transcriptase inhibitors (NNRTIs) against a panel of HIV-1 PPT mutants. We also tested several of our promising INSTIs and NNRTIs in these assays. No measurable loss in potency was observed for either INSTIs or NNRTIs against the HIV-1 PPT mutants. This suggests that HIV-1 PPT mutants are not able, by themselves, to confer resistance to INSTIs or NNRTIs.
Project description:Most of SARS-CoV-2 neutralizing antibodies (nAbs) targeted the receptor binding domain (RBD) of the SARS-CoV-2 spike (S) protein. However, mutations at RBD sequences found in the emerging SARS-CoV-2 variants greatly reduced the effectiveness of nAbs. Here we showed that four nAbs, S2-4D, S2-5D, S2-8D, and S2-4A, which recognized a conserved epitope in the S2 subunit of the S protein, can inhibit SARS-CoV-2 infection through blocking the S protein-mediated membrane fusion. Notably, these four nAbs exhibited broadly neutralizing activity against SARS-CoV-2 Alpha, Gamma, Delta, and Epsilon variants. Antisera collected from mice immunized with the identified epitope peptides of these four nAbs also exhibited potent virus neutralizing activity. Discovery of the S2-specific nAbs and their unique antigenic epitopes paves a new path for development of COVID-19 therapeutics and vaccines. IMPORTANCE The spike (S) protein on the surface of SARS-CoV-2 mediates receptor binding and virus-host cell membrane fusion during virus entry. Many neutralizing antibodies (nAbs), which targeted the receptor binding domain (RBD) of S protein, lost the neutralizing activity against the newly emerging SARS-CoV-2 variants with sequence mutations at the RBD. In contrast, the nAb against the highly conserved S2 subunit, which plays the key role in virus-host cell membrane fusion, was poorly discovered. We showed that four S2-specific nAbs, S2-4D, S2-5D, S2-8D, and S2-4A, inhibited SARS-CoV-2 infection through blocking the S protein-mediated membrane fusion. These nAbs exhibited broadly neutralizing activity against Alpha, Gamma, Delta, and Epsilon variants. Antisera induced by the identified epitope peptides also possessed potent neutralizing activity. This work not only unveiled the S2-specific nAbs but also discovered an immunodominant epitope in the S2 subunit that can be rationally designed as the broad-spectrum vaccine against the SARS-like coronaviruses.
Project description:EK1 peptide is a membrane fusion inhibitor with broad-spectrum activity against human coronaviruses (CoVs). In the outbreak of COVID-19, we generated a lipopeptide EK1V1 by modifying EK1 with cholesterol, which exhibited significantly improved antiviral activity. In this study, we surprisingly found that EK1V1 also displayed potent cross-inhibitory activities against divergent HIV-1, HIV-2, and simian immunodeficiency virus (SIV) isolates. Consistently, the recently reported EK1 derivative EK1C4 and SARS-CoV-2 derived fusion inhibitor lipopeptides (IPB02 ∼ IPB09) also inhibited HIV-1 Env-mediated cell-cell fusion and infection efficiently. In the inhibition of a panel of HIV-1 mutants resistant to HIV-1 fusion inhibitors, EK1V1 and IPB02-based inhibitors exhibited significantly decreased or increased activities, suggesting the heptad repeat-1 region (HR1) of HIV-1 gp41 being their target. Furthermore, the sequence alignment and molecular docking analyses verified the target site and revealed the mechanism underlying the resistance. Combined, we conclude that this serendipitous discovery provides a proof-of-concept for a common mechanism of viral fusion and critical information for the development of broad-spectrum antivirals.