Anti-herpetic and anti-dengue activity of abietane ferruginol analogues synthesized from (+)-dehydroabietylamine

The abietane-type diterpenoid (+)-ferruginol (1), a bioactive compound isolated from several plants, has attracted much attention as consequence of its pharmacological properties, which includes antibacterial, antifungal, antimicrobial, cardioprotective, anti-oxidative, anti-plasmodial, leishmanicidal, anti-ulcerogenic, anti-inflammatory and antitumor actions. In this study, we report on the antiviral evaluation of ferruginol (1) and several analogues synthesized from commercial (+)-dehydroabietylamine. Thus, the activity against Human Herpesvirus type 1, Human Herpesvirus type 2 and Dengue Virus type 2, was studied. Two ferruginol analogues showed high antiviral selectivity index and reduced viral plaque-size in post-infection stages against both Herpes and Dengue viruses. A promising lead, compound 8, was ten-fold more potent (EC50 = 1.4 μM) than the control ribavirin against Dengue Virus type 2. Our findings suggest that the 12-hydroxyabieta-8,11,13-triene skeleton, which is characteristic of the diterpenoid ferruginol (1), is an interesting molecular scaffold for development of novel antivirals. In addition, the cytotoxic and antifungal activities of the synthesized ferruginol analogues have also been investigated. (©)20155 Elsevier Science. All rights reserved.

Development of a novel DNA-launched dengue virus type 2 infectious clone assembled in a bacterial artificial chromosome

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We cloned a DENV-2 infectious cDNA into a BAC under the control of the CMV promoter.

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We assessed the production of infectious particles.

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We rescued infectious viruses after serial passages in C6/36 cells.

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Parental and recombinant viruses were similar in plaque and syncytia phenotypes.

Major progress in Dengue virus (DENV) biology has resulted from the use of infectious clones obtained through reverse genetics. The construction of these clones is commonly based on high- or low-copy number plasmids, yeast artificial chromosomes, yeast-Escherichia coli shuttle vectors, and bacterial artificial chromosomes (BACs). Prokaryotic promoters have consistently been used for the transcription of these clones. The goal of this study was to develop a novel DENV infectious clone in a BAC under the control of the cytomegalovirus immediate-early promoter and to generate a virus with the fusion envelope-green fluorescent protein in an attempt to track virus infection. The transfection of Vero cells with a plasmid encoding the DENV infectious clone facilitated the recovery of infectious particles that increased in titer after serial passages in C6/36 cells. The plaque size and syncytia phenotypes of the recombinant virus were similar to those of the parental virus. Despite the observation of autonomous replication and the detection of low levels of viral genome after two passages, the insertion of green fluorescent protein and Renilla luciferase reporter genes negatively impacted virus rescue. To the best of our knowledge, this is the first study using a DENV infectious clone under the control of the cytomegalovirus promoter to facilitate the recovery of recombinant viruses without the need for in vitro transcription. This novel molecular clone will be useful for establishing the molecular basis of replication, assembly, and pathogenesis, evaluating potential antiviral drugs, and the development of vaccine candidates for attenuated recombinant viruses.

Phylogenetic reconstruction of dengue virus type 2 in Colombia

Background

Dengue fever is perhaps the most important viral re-emergent disease especially in tropical and sub-tropical countries, affecting about 50 million people around the world yearly. In Colombia, dengue virus was first detected in 1971 and still remains as a major public health issue. Although four viral serotypes have been recurrently identified, dengue virus type 2 (DENV-2) has been involved in the most important outbreaks during the last 20 years, including 2010 when the fatality rate highly increased. As there are no major studies reviewing virus origin and genotype distribution in this country, the present study attempts to reconstruct the phylogenetic history of DENV-2 using a sequence analysis from a 224 bp PCR-amplified product corresponding to the carboxyl terminus of the envelope (E) gene from 48 Colombian isolates.

Results

As expected, the oldest isolates belonged to the American genotype (subtype V), but the strains collected since 1990 represent the American/Asian genotype (subtype IIIb) as previously reported in different American countries. Interestingly, the introduction of this genotype coincides with the first report of dengue hemorrhagic fever in Colombia at the end of 1989 and the increase of cases during the next years.

Conclusion

After replacement of the American genotype, several lineages of American/Asian subtype have rapidly spread all over the country evolving in new clades. Nevertheless, the direct association of these new variants in the raise of lethality rate observed during the last outbreak has to be demonstrated.

Phylogenetic history demonstrates two different lineages of dengue type 1 virus in Colombia

Background

Dengue Fever is one of the most important viral re-emergent diseases affecting about 50 million people around the world especially in tropical and sub-tropical countries. In Colombia, the virus was first detected in the earliest 70's when the disease became a major public health concern. Since then, all four serotypes of the virus have been reported. Although most of the huge outbreaks reported in this country have involved dengue virus serotype 1 (DENV-1), there are not studies about its origin, genetic diversity and distribution.

Results

We used 224 bp corresponding to the carboxyl terminus of envelope (E) gene from 74 Colombian isolates in order to reconstruct phylogenetic relationships and to estimate time divergences. Analyzed DENV-1 Colombian isolates belonged to the formerly defined genotype V. Only one virus isolate was clasified in the genotype I, likely representing a sole introduction that did not spread. The oldest strains were closely related to those detected for the first time in America in 1977 from the Caribbean and were detected for two years until their disappearance about six years later. Around 1987, a split up generated 2 lineages that have been evolving separately, although not major aminoacid changes in the analyzed region were found.

Conclusion

DENV-1 has been circulating since 1978 in Colombia. Yet, the phylogenetic relationships between strains isolated along the covered period of time suggests that viral strains detected in some years, although belonging to the same genotype V, have different recent origins corresponding to multiple re-introduction events of viral strains that were circulating in neighbor countries. Viral strains used in the present study did not form a monophyletic group, which is evidence of a polyphyletic origin. We report the rapid spread patterns and high evolution rate of the different DENV-1 lineages.

Simultaneous circulation of genotypes I and III of dengue virus 3 in Colombia

BACKGROUND

Dengue is a major health problem in tropical and subtropical regions. In Colombia, dengue viruses (DENV) cause about 50,000 cases annually, 10% of which involve Dengue Haemorrhagic Fever/Dengue Shock Syndrome. The picture is similar in other surrounding countries in the Americas, with recent outbreaks of severe disease, mostly associated with DENV serotype 3, strains of the Indian genotype, introduced into the Americas in 1994.

RESULTS

The analysis of the 3'end (224 bp) of the envelope gene from 32 DENV-3 strains recently recovered in Colombia confirms the circulation of the Indian genotype, and surprisingly the co-circulation of an Asian-Pacific genotype only recently described in the Americas.

CONCLUSION

These results have important implications for epidemiology and surveillance of DENV infection in Central and South America. Molecular surveillance of the DENV genotypes infecting humans could be a very valuable tool for controlling/mitigating the impact of the DENV infection.

Down-regulation of Bcl-2 in rat substantia nigra after focal cerebral ischemia

After occlusion of the middle cerebral artery in rats, a robust neuronal loss occurs in the ipsilateral substantia nigra reticulata. In this study we have assessed whether degeneration of the substantia nigra is accompanied by changes in the expression of the anti-apoptotic protein Bcl-2. Neuronal loss was assessed by neuronal nuclei (NeuN) immunoreactivity. A significant decrease of Bcl-2 expression was observed in the substantia nigra 12, 24 and 72 h after middle cerebral artery occlusion. These results suggest that the secondary neuronal loss in the substantia nigra could be related with the modification of proteins regulating programmed cell death. Exo-focal cell death may explain the appearance of neuropsychiatric symptoms that are not correlated with the primary site of lesion.