RESUMO
Since the efficiency in the transcription of the HIV genome contributes to the success of viral replication and infectivity, we investigated the downregulating effects of the spirobisindole alkaloids globospiramine (1), deoxyvobtusine (2), and vobtusine lactone (3) from the endemic Philippine medicinal plant, Voacanga globosa, during HIV gene transcription. Alkaloids 1-3 were explored for their inhibitory activity on TNF-α-induced viral replication in two latently HIV-infected cell lines, OM10.1 and J-Lat. The induction of HIV replication from OM10.1 and J-Lat cells elicited by TNF-α was blocked by globospiramine (1) within noncytotoxic concentrations. Furthermore, globospiramine (1) was found to target the NF-ĸB activation cascade in a dose-dependent manner when the transcriptional step at which inhibitory activity is exerted was examined in TNF-α-induced 293 human cells using transient reporter (luciferase) gene expression systems (HIV LTR-luc, ĸB-luc, and mutant ĸB-luc). Interrogation through molecular docking against the NF-ĸB p50/p65 heterodimer and target sites of the subunits comprising the IKK complex revealed high binding affinities of globospiramine (1) against the S281 pocket of the p65 subunit (BE = -9.2 kcal/mol) and the IKKα activation loop (BE = -9.1 kcal/mol). These findings suggest globospiramine (1) as a molecular inspiration to discover new alkaloid-based anti-HIV derivatives.
Assuntos
Alcaloides/farmacologia , Infecções por HIV/metabolismo , HIV-1/fisiologia , Quinase I-kappa B/metabolismo , Subunidade p50 de NF-kappa B/metabolismo , Fator de Transcrição RelA/metabolismo , Voacanga/química , Alcaloides/química , Linhagem Celular , Relação Dose-Resposta a Droga , Infecções por HIV/tratamento farmacológico , HIV-1/efeitos dos fármacos , Células HL-60 , Humanos , Quinase I-kappa B/química , Alcaloides Indólicos/farmacologia , Modelos Biológicos , Simulação de Acoplamento Molecular , NF-kappa B/metabolismo , Subunidade p50 de NF-kappa B/química , Extratos Vegetais/química , Transdução de Sinais/efeitos dos fármacos , Compostos de Espiro/farmacologia , Fator de Transcrição RelA/química , Fator de Necrose Tumoral alfa/farmacologia , Latência Viral/efeitos dos fármacos , Replicação Viral/efeitos dos fármacosRESUMO
Emergence of drug resistance demands new therapeutic strategies against the human immunodeficiency virus (HIV). Currently, there is an increasing research focus on targeting gene expression-the crucial step wherein new viruses and new viral strains are amplified. Moreover, natural products are also being considered as potential candidates for new antivirals. We screened the extract obtained from a Philippine medicinal plant, Mentha cordifolia (Mc). In this study, we demonstrated that Mc ammonium sulfate extract has antiretroviral activity against HIV. HIV-1 latently infected cells (OM10.1) were pretreated with Mc extract and activated with TNFα. In treated cells, viral replication was inhibited in both cell culture supernatant and whole cell lysates. The level of viral production, as measured by the viral p24 protein concentration, was very much inhibited under noncytotoxic concentrations to the similar level without addition of TNFα. Luciferase assays, however, showed that Mc does not inhibit the HIV-1 long terminal repeat-driven gene expression. IκBα degradation and p65 nuclear translocation was also not affected as visualized through Western blot and immunofluorescence. These observations demonstrated that Mc possessed an antiviral component against HIV-1 and warrant further work to explore its target of action at a later step of gene expression. Our study introduces a potential source of a lead compound that targets steps in the HIV life cycle.
Assuntos
Infecções por HIV , HIV-1 , Mentha , Antivirais/farmacologia , Linhagem Celular , Humanos , Extratos Vegetais/farmacologia , Replicação ViralRESUMO
To find histone deacetylase 3 (HDAC3)-selective inhibitors, a series of 504 candidates was assembled using "click chemistry", by reacting nine alkynes bearing a zinc-binding group with 56 azide building blocks in the presence of Cu(I) catalyst. Screening of the 504-member triazole library against HDAC3 and other HDAC isozymes led to the identification of potent and selective HDAC3 inhibitors T247 and T326. These compounds showed potent HDAC3 inhibition with submicromolar IC50s, whereas they did not strongly inhibit other isozymes. Compounds T247 and T326 also induced a dose-dependent selective increase of NF-κB acetylation in human colon cancer HCT116 cells, indicating selective inhibition of HDAC3 in the cells. In addition, these HDAC3-selective inhibitors induced growth inhibition of cancer cells, and activated HIV gene expression in latent HIV-infected cells. These findings indicate that HDAC3-selective inhibitors are promising candidates for anticancer drugs and antiviral agents. This work also suggests the usefulness of the click chemistry approach to find isozyme-selective HDAC inhibitors.
Assuntos
Química Click/métodos , Inibidores de Histona Desacetilases/química , Histona Desacetilases/efeitos dos fármacos , Avaliação Pré-Clínica de Medicamentos , Células HCT116 , Humanos , Triazóis/químicaRESUMO
Transcriptional activity of nuclear factor kappaB (NF-kappaB) is induced by environmental signals including inflammation, UV irradiation and oxidative stress. It was shown that the NF-kappaB activity greatly contributes to the skin photoaging process. Thus, it is plausible that NF-kappaB inhibitors could directly prevent skin photoaging. In this study, we found that Magnolia ovovata extract inhibited NF-kappaB-mediated gene expression and demonstrated that external swabbing with Magnolia extract preventing skin photoaging processes through keratinocyte hyperproliferation and degradation of collagen fibers in mice skin. We have identified magnolol as the solely responsible active compound in Magnolia extract. Magnolol effectively inhibited the NF-kappaB-dependent transcription, but no effect was observed with other inducible transcription factors such as activator protein-1 (AP-1) and cyclic-AMP responsive element-binding protein (CREB). In addition, magnolol was effective in inhibiting the production of basic fibroblast growth factor (bFGF) and matrix metalloprotease-1 (MMP-1) from the cells overexpressing p65, a major subunit of NF-kappaB. Although magnolol did not affect the phosphorylation and degradation of IkappaBalpha, it inhibited the nuclear translocation of the activated NF-kappaB. These findings suggest that Magnolia extract and its active component magnolol can be used to prevent the skin photoaging via inhibiting NF-kappaB by external topical application.