Limits...
A reduction of viral mRNA, proteins and induction of altered morphogenesis reveals the anti-HTLV-1 activity of the labdane-diterpene myriadenolide in vitro.

Martins CP, Gomes OA, Martins ML, de Carvalho LD, de Souza JG, Da Fonseca FG, dos Santos RG, Andrade MS, Zani CL, de Souza-Fagundes EM, Barbosa-Stancioli EF - BMC Microbiol. (2014)

Bottom Line: We demonstrated that this natural product was able to inhibit the expression of gag-pol mRNA and substantially reduced the expression of the structural proteins p19 and gp46.Comparison of treated and untreated cells shows that AMY alters both the morphology and the release of viral particles.We demonstrated that the labdane diterpene myriadenolide reduced the expression of the structural proteins and the budding of viral particles, besides induces altered morphogenesis of HTLV-1, conferring on AMY a new antiviral activity that may be useful for the development of new compounds with specific anti-HTLV-1 activity.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Virologia Básica e Aplicada (LVBA), Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Avenida Antônio Carlos, 6627, Belo Horizonte, Minas Gerais, Brazil. cpsmartins@yahoo.com.br.

ABSTRACT

Background: Human T-lymphotropic virus 1 (HTLV-1) has been associated with leukemia/lymphoma (ATL) and myelopathy/tropical spastic paraparesis (HAM/TSP), in addition to other inflammatory diseases as well as infection complications. Therapeutic approaches for HTLV-1-related pathologies are limited. The labdane diterpene myriadenolide (AMY) is a natural product that exhibit biological activities, such as anti-inflammatory and antiviral activity as reported for HIV and herpesvirus.

Results: We demonstrated that this natural product was able to inhibit the expression of gag-pol mRNA and substantially reduced the expression of the structural proteins p19 and gp46. Comparison of treated and untreated cells shows that AMY alters both the morphology and the release of viral particles. The Atomic Force Microscopy assay showed that the AMY treatment reduced the number of particles on the cell surface by 47%.

Conclusion: We demonstrated that the labdane diterpene myriadenolide reduced the expression of the structural proteins and the budding of viral particles, besides induces altered morphogenesis of HTLV-1, conferring on AMY a new antiviral activity that may be useful for the development of new compounds with specific anti-HTLV-1 activity.

Show MeSH

Related in: MedlinePlus

Transmission electron microscopy of MT-2 cells treated with AMY. MT-2 cell suspensions were cultivated with or without 1 μM of AMY. Twenty-four hours post-incubation, cells were stained with uranyl acetate and examined under a Tecnai G2 F20 electron microscope (FEI, USA). Panels a to c represent MT-2 untreated cells and D to F are MT-2 cells after AMY treatment. Viral budding is reduced in AMY treated cells when compared to mock-treated cells (panels a, b, d and e). HTLV-1 typical particles are seen when cells are untreated (panel c; arrow) whereas HTLV-1 atypical particles (panel f; arrows) are seen in AMY treated cells. Scale bars are represented in each panel.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC4302425&req=5

Fig4: Transmission electron microscopy of MT-2 cells treated with AMY. MT-2 cell suspensions were cultivated with or without 1 μM of AMY. Twenty-four hours post-incubation, cells were stained with uranyl acetate and examined under a Tecnai G2 F20 electron microscope (FEI, USA). Panels a to c represent MT-2 untreated cells and D to F are MT-2 cells after AMY treatment. Viral budding is reduced in AMY treated cells when compared to mock-treated cells (panels a, b, d and e). HTLV-1 typical particles are seen when cells are untreated (panel c; arrow) whereas HTLV-1 atypical particles (panel f; arrows) are seen in AMY treated cells. Scale bars are represented in each panel.

Mentions: The TEM and AFM analyses of MT-2 cells were performed 24 h post-incubation in the presence or absence of 1 μM AMY (Figure 4). Comparison of treated and untreated cells by TEM shows that treatment with AMY alters both the release of viral particles and the morphology (emphasized in Figure 4(b)/4(e) and 4(c)/4(f), respectively). However, we do acknowledge that the TEM may not be able to precisely determine whether these are actual complete virus particles or just empty capsids. Nonetheless, this observation was corroborated using AFM (Figure 5), and because this technique favors counting the number of particles per field evaluated, it was shown that AMY treatment reduced the number of particles on the cell surface by 47%. Of the 412 virus particles quantified by TEM, 229 viral particles were measured in cells treated with AMY and 183 in untreated cells. In the untreated cells, the virus particles ranged from 53 to 212 nm (mean 90.6 nm), and in the treated cells, they ranged from 41 to 171 nm (mean 91.55 nm). Using AFM, a total of 158 virus particles were measured (55 and 103 particles in AMY treated and untreated cells, respectively) and the size of viruses ranged from 75.8 to 273.6 nm (mean 148.9 nm) in untreated cells, whereas the sizes ranged from 42.4 to 175.5 nm (mean 97.9 nm) in AMY treated cells.Figure 4


A reduction of viral mRNA, proteins and induction of altered morphogenesis reveals the anti-HTLV-1 activity of the labdane-diterpene myriadenolide in vitro.

Martins CP, Gomes OA, Martins ML, de Carvalho LD, de Souza JG, Da Fonseca FG, dos Santos RG, Andrade MS, Zani CL, de Souza-Fagundes EM, Barbosa-Stancioli EF - BMC Microbiol. (2014)

Transmission electron microscopy of MT-2 cells treated with AMY. MT-2 cell suspensions were cultivated with or without 1 μM of AMY. Twenty-four hours post-incubation, cells were stained with uranyl acetate and examined under a Tecnai G2 F20 electron microscope (FEI, USA). Panels a to c represent MT-2 untreated cells and D to F are MT-2 cells after AMY treatment. Viral budding is reduced in AMY treated cells when compared to mock-treated cells (panels a, b, d and e). HTLV-1 typical particles are seen when cells are untreated (panel c; arrow) whereas HTLV-1 atypical particles (panel f; arrows) are seen in AMY treated cells. Scale bars are represented in each panel.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4302425&req=5

Fig4: Transmission electron microscopy of MT-2 cells treated with AMY. MT-2 cell suspensions were cultivated with or without 1 μM of AMY. Twenty-four hours post-incubation, cells were stained with uranyl acetate and examined under a Tecnai G2 F20 electron microscope (FEI, USA). Panels a to c represent MT-2 untreated cells and D to F are MT-2 cells after AMY treatment. Viral budding is reduced in AMY treated cells when compared to mock-treated cells (panels a, b, d and e). HTLV-1 typical particles are seen when cells are untreated (panel c; arrow) whereas HTLV-1 atypical particles (panel f; arrows) are seen in AMY treated cells. Scale bars are represented in each panel.
Mentions: The TEM and AFM analyses of MT-2 cells were performed 24 h post-incubation in the presence or absence of 1 μM AMY (Figure 4). Comparison of treated and untreated cells by TEM shows that treatment with AMY alters both the release of viral particles and the morphology (emphasized in Figure 4(b)/4(e) and 4(c)/4(f), respectively). However, we do acknowledge that the TEM may not be able to precisely determine whether these are actual complete virus particles or just empty capsids. Nonetheless, this observation was corroborated using AFM (Figure 5), and because this technique favors counting the number of particles per field evaluated, it was shown that AMY treatment reduced the number of particles on the cell surface by 47%. Of the 412 virus particles quantified by TEM, 229 viral particles were measured in cells treated with AMY and 183 in untreated cells. In the untreated cells, the virus particles ranged from 53 to 212 nm (mean 90.6 nm), and in the treated cells, they ranged from 41 to 171 nm (mean 91.55 nm). Using AFM, a total of 158 virus particles were measured (55 and 103 particles in AMY treated and untreated cells, respectively) and the size of viruses ranged from 75.8 to 273.6 nm (mean 148.9 nm) in untreated cells, whereas the sizes ranged from 42.4 to 175.5 nm (mean 97.9 nm) in AMY treated cells.Figure 4

Bottom Line: We demonstrated that this natural product was able to inhibit the expression of gag-pol mRNA and substantially reduced the expression of the structural proteins p19 and gp46.Comparison of treated and untreated cells shows that AMY alters both the morphology and the release of viral particles.We demonstrated that the labdane diterpene myriadenolide reduced the expression of the structural proteins and the budding of viral particles, besides induces altered morphogenesis of HTLV-1, conferring on AMY a new antiviral activity that may be useful for the development of new compounds with specific anti-HTLV-1 activity.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Virologia Básica e Aplicada (LVBA), Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Avenida Antônio Carlos, 6627, Belo Horizonte, Minas Gerais, Brazil. cpsmartins@yahoo.com.br.

ABSTRACT

Background: Human T-lymphotropic virus 1 (HTLV-1) has been associated with leukemia/lymphoma (ATL) and myelopathy/tropical spastic paraparesis (HAM/TSP), in addition to other inflammatory diseases as well as infection complications. Therapeutic approaches for HTLV-1-related pathologies are limited. The labdane diterpene myriadenolide (AMY) is a natural product that exhibit biological activities, such as anti-inflammatory and antiviral activity as reported for HIV and herpesvirus.

Results: We demonstrated that this natural product was able to inhibit the expression of gag-pol mRNA and substantially reduced the expression of the structural proteins p19 and gp46. Comparison of treated and untreated cells shows that AMY alters both the morphology and the release of viral particles. The Atomic Force Microscopy assay showed that the AMY treatment reduced the number of particles on the cell surface by 47%.

Conclusion: We demonstrated that the labdane diterpene myriadenolide reduced the expression of the structural proteins and the budding of viral particles, besides induces altered morphogenesis of HTLV-1, conferring on AMY a new antiviral activity that may be useful for the development of new compounds with specific anti-HTLV-1 activity.

Show MeSH
Related in: MedlinePlus