Lipids fluctuations in mosquitoes upon arboviral infections.

Arboviruses are responsible for several emerging and re-emerging infectious diseases, with dengue, Zika virus disease and Chikungunya fever being the most important arboviral diseases nowadays. Infection of these viruses depends primarily on its ability to replicate and disseminate in mosquitoes. Since these viruses are enveloped, viral replication, assembly and release occurs in the cellular membranes, which depends on the manipulation of host lipid metabolism. Specifically in mammalian cells replication, they use host lipids to establish a compartment known as replication complex that contains the replicase complex. This complex includes viral RNA, proteins and host factors necessary for a successful replication in mammalian cells. Although little is known about extrinsic factor(s) needed for arbovirus replication in vectors,recent reports show that high lipid concentrations are related with increased viral replication in mosquito cells infected with dengue, Zika and Chikungunya viruses. Here, we present a review that focuses on the cellular mechanisms and the lipid environment alteration in mosquito vector after arbovirus infection and their relationship with arbovirus replication.

Virucidal Activity of Gold Nanoparticles Synthesized by Green Chemistry Using Garlic Extract.

Measles virus (MeV) is a paramyxovirus that infects humans, principally children. Despite the existence of an effective and safe vaccine, the number of cases of measles has increased due to lack of vaccination coverage. The World Health Organization (WHO) reports that the number of cases worldwide multiplied fourfold between January and March 2019, to 112,000. Today, there is no treatment available for MeV. In recent years, it has been demonstrated that natural extracts (herbal or algal) with antiviral activity can also work as reducing agents that, in combination with nanotechnology, offer an innovative option to counteract viral infections. Here, we synthetized and evaluated the antiviral activity of gold nanoparticles using garlic extract (Allium sativa) as a reducing agent (AuNPs-As). These nanoparticles actively inhibited MeV replication in Vero cells at a 50% effective concentration (EC50) of 8.829 µg/mL, and the selectivity index (SI) obtained was 16.05. AuNPs-As likely inhibit viral infection by blocking viral particles directly, showing a potent virucidal effect. Gold nanoparticles may be useful as a promising strategy for treating and controlling the infection of MeV and other related enveloped viruses.

Inhibitory Effect of Cuphea aequipetala Extracts on Murine B16F10 Melanoma In Vitro and In Vivo.

Cuphea aequipetala (C. aequipetala) has been used in Mexican traditional medicine since prehispanic times to treat tumors. In this paper, we evaluated the antiproliferative and apoptotic effect of the methanolic and aqueous extracts of C. aequipetala on several cancer cell lines including the B16F10 cell line of murine melanoma and carried a murine model assay. In vitro assay analyzed the effect in the cellular cycle and several indicators of apoptosis, such as the caspase-3 activity, DNA fragmentation, phosphatidylserine exposure (Annexin-V), and induction of cell membrane permeabilization (propidium iodide) in the B16F10 cells. In vivo, groups of C57BL/6 female mice were subcutaneously injected with 5x105 B16F10 cells and treated with 25 mg/mL of C. aequipetala extracts via oral. Aqueous and methanolic extracts showed a cytotoxic effect in MCF-7, HepG2, and B16F10 cell lines. The methanolic extract showed more antiproliferative effect with less concentration, and for this reason, the in vitro experiments were only continued with it. This extract was able to induce accumulation of cells on G1 phase of the cell cycle; moreover, it was able to induce DNA fragmentation and increase the activity of caspase-3 in B16F10 cells. On the other hand, in the murine model of melanoma, the aqueous extract showed a greater reduction of tumor size in comparison with the methanolic extract, showing an 80% reduction versus one of around 31%, both compared with the untreated control, indicating a better antitumor effect of C. aequipetala aqueous extract via oral administration. In conclusion, the in vitro data showed that both C. aequipetala extracts were able to induce cytotoxicity through the apoptosis pathway in B16F10 cells, and in vivo, the oral administration of aqueous extract reduces the melanoma tumoral mass, suggesting an important antitumoral effect and the perspective to search for effector molecules involved in it.

Virucidal and Synergistic Activity of Polyphenol-Rich Extracts of Seaweeds against Measles Virus.

Although preventable by vaccination, Measles still causes thousands of deaths among young children worldwide. The discovery of new antivirals is a good approach to control new outbreaks that cause such death. In this study, we tested the antiviral activity against Measles virus (MeV) of Polyphenol-rich extracts (PPs) coming from five seaweeds collected and cultivated in Mexico. An MTT assay was performed to determine cytotoxicity effect, and antiviral activity was measured by syncytia reduction assay and confirmed by qPCR. PPs from Ecklonia arborea (formerly Eisenia arborea, Phaeophyceae) and Solieria filiformis (Rhodophyta) showed the highest Selectivity Index (SI), >3750 and >576.9 respectively. Both PPs extracts were selected to the subsequent experiments owing to their high efficacy and low cytotoxicity compared with ribavirin (SI of 11.57). The combinational effect of PPs with sulphated polysaccharides (SPs) and ribavirin were calculated by using Compusyn software. Synergistic activity was observed by combining both PPs with low concentrations of Solieria filiformis SPs (0.01 µg/mL). The antiviral activity of the best combinations was confirmed by qPCR. Virucidal assay, time of addition, and viral penetration evaluations suggested that PPs act mainly by inactivating the viral particle. To our knowledge, this is the first report of the virucidal effect of Polyphenol-rich extracts of seaweeds.

Synergistic Effects of Sulfated Polysaccharides from Mexican Seaweeds against Measles Virus.

Sulfated polysaccharides (SPs) extracted from five seaweed samples collected or cultivated in Mexico (Macrocystis pyrifera, Eisenia arborea, Pelvetia compressa, Ulva intestinalis, and Solieria filiformis) were tested in this study in order to evaluate their effect on measles virus in vitro. All polysaccharides showed antiviral activity (as measured by the reduction of syncytia formation) and low cytotoxicity (MTT assay) at inhibitory concentrations. SPs from Eisenia arborea and Solieria filiformis showed the highest antiviral activities (confirmed by qPCR) and were selected to determine their combined effect. Their synergistic effect was observed at low concentrations (0.0274 µg/mL and 0.011 µg/mL of E. arborea and S. filiformis SPs, resp.), which exhibited by far a higher inhibitory effect (96% syncytia reduction) in comparison to the individual SP effects (50% inhibition with 0.275 µg/mL and 0.985 µg/mL of E. arborea and S. filiformis, resp.). Time of addition experiments and viral penetration assays suggest that best activities of these SPs occur at different stages of infection. The synergistic effect would allow reducing the treatment dose and toxicity and minimizing or delaying the induction of antiviral resistance; sulfated polysaccharides of the tested seaweed species thus appear as promising candidates for the development of natural antiviral agents.

Innocuity and anti-Newcastle-virus-activity of Cladosiphon okamuranus fucoidan in chicken embryos.

This study evaluated the potential toxicity and antiviral activity of fucoidan from Cladosiphon okamuranus against Newcastle disease virus (NDV), one of the most serious threats to the poultry industry in the world. Toxicity was assayed on chicken embryo fibroblast (CEF) secondary cultures at concentrations ranging from 0.1 to 1500 µg per mL culture medium, assessing the cell viability by the yellow tetrazolium MTT (3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide) assay, and on 9-day-old embryonated chicken eggs by inoculation of 2 to 500 µg doses in the allantoic cavity, assessing the embryos morphology and liver histology. At 48 h post-inoculation, viability of CEF exposed to concentrations up to 10 µg/mL was not significantly affected, and the 50% cytotoxic concentration was estimated as of 1062 µg/mL; after exposure in ovo, some chick embryos showed liver steatosis when treated with fucoidan doses over 20 µg per egg (15 to 28% at 200 µg, 27 to 56% at 500 µg), but no change was detected in their size or aspect. Antiviral activity was tested by treating 9-day-old embryos via the allantoic route with 0.25 to 16 µg fucoidan doses that were applied at different times (-1, 0 and +1 h) relative to the inoculation of 10,000 folds the 50% Tissue Culture Infective Dose (TCID50) of the NDV, La Sota strain. At 72 h post infection, virus titration in the allantoic fluid by hemagglutination assay (HA) showed a considerable and significant inhibition of infectivity for all doses, the best result (a 90% decrease) being obtained in embryos treated with 1 µg fucoidan one hour before infection. Viral RNA semi-quantification in pooled liver and small intestine of embryos that had been treated with 4 and 16 µg fucoidan 1 h before the infection showed reductions of the virus replication by 60 and 99.8%, respectively. Since this high anti-NDV activity in ovo was obtained with quite innocuous doses, fucoidan from C. okamuranus could be a potential low-toxicity antiviral compound to be used in areas exposed to NDV.

In vitro anti-canine distemper virus activity of fucoidan extracted from the brown alga Cladosiphon okamuranus.

Canine distemper virus (CDV) is a morbillivirus related to measles virus that infects dogs and other carnivores. CDV has a significant global impact on animal health; however, there is no current antiviral treatment for CDV infection. In recent years, it has been demonstrated that sulfated polysaccharides exhibit antiviral properties both in vivo and in vitro, despite their low cytotoxicity to host cells. Fucoidan is a sulfated polysaccharide found in the cell wall matrix of brown algae. In this study, we evaluated in vitro anti-CDV activity of fucoidan, which was derived from Cladosiphon okamuranus. Fucoidan actively inhibited CDV replication in Vero cells at a 50 % inhibitory concentration (IC50) of 0.1 µg/ml. The derived selectivity index (SI50) was >20,000. This polysaccharide likely inhibits viral infection by interference in the early steps and by inhibiting CDV-mediated cell fusion. Fucoidan may be useful in development of pharmacological strategies to treat and control CDV infection.

In vitro characterization of the antiviral activity of fucoidan from Cladosiphon okamuranus against Newcastle Disease Virus.

BACKGROUND: Newcastle Disease Virus (NDV) causes a serious infectious disease in birds that results in severe losses in the worldwide poultry industry. Despite vaccination, NDV outbreaks have increased the necessity of alternative prevention and control measures. Several recent studies focused on antiviral compounds obtained from natural resources. Many extracts from marine organisms have been isolated and tested for pharmacological purposes, and their antiviral activity has been demonstrated in vitro and in vivo. Fucoidan is a sulfated polysaccharide present in the cell wall matrix of brown algae that has been demonstrated to inhibit certain enveloped viruses with low toxicity. This study evaluated the potential antiviral activity and the mechanism of action of fucoidan from Cladosiphon okamuranus against NDV in the Vero cell line. METHODS: The cytotoxicity of fucoidan was determined by the MTT assay. To study its antiviral activity, fusion and plaque-forming unit (PFU) inhibition assays were conducted. The mechanism of action was determined by time of addition, fusion inhibition, and penetration assays. The NDV vaccine strain (La Sota) was used in the fusion inhibition assays. PFU and Western blot experiments were performed using a wild-type lentogenic NDV strain. RESULTS: Fucoidan exhibited antiviral activity against NDV La Sota, with an obtained IS50 >2000. In time of addition studies, we observed viral inhibition in the early stages of infection (0-60 min post-infection). The inhibition of viral penetration experiments with a wild-type NDV strain supported this result, as these experiments demonstrated a 48% decrease in viral infection as well as reduced HN protein expression. Ribavirin, which was used as an antiviral control, exhibited lower antiviral activity than fucoidan and high toxicity at active doses. In the fusion assays, the number of syncytia was significantly reduced (70% inhibition) when fucoidan was added before cleavage of the fusion protein, perhaps indicating a specific interaction between fucoidan and the F0 protein. CONCLUSION: The results of this study suggest that fucoidan from C. okamuranus represents a potential low-toxicity antiviral compound for the poultry industry, and our findings provide a better understanding of the mode of action of sulfated polysaccharides.

WT1 silencing by RNAi synergizes with chemotherapeutic agents and induces chemosensitization to doxorubicin and cisplatin in B16F10 murine melanoma cells.

The Wilm's tumor gene (WT1), encoding a transcription factor that modulates the expression of certain genes that are involved in proliferation and apoptosis, is overexpressed in numerous solid tumors. WT1 is important for cell proliferation and in the diagnosis of melanoma. The objectives of this study were to investigate whether WT1 silencing is capable of synergizing with chemotherapeutic agents and whether this silencing is capable of sensitizing cancer cells to doxorubicin and cisplatin in the B16F10 murine melanoma cell line. In the present study, B16F10 cells were simultaneously treated with median lethal doses (LD50s) of WT1-1 or WT1-2 small hairpin RNAs (shRNAs) and chemotherapeutic agents. A total of 24 h post-transfection, a [3-(4,5-dimethylthiazol-2yl)-2,5- diphenyl tetrazolium bromide assay] MTT assay was performed. To determine whether shRNA interference (shRNAi) is capable of sensitizing B16F10 cells to chemotherapeutic agents, cells were transfected with an LD50 of each of the recombinant plasmids, treated with varying concentrations of doxorubicin or cisplatin 24 h post-transfection, and analyzed 48 h later for inhibition of cell proliferation using the MTT assay. We observed that WT1-RNAi and the two chemotherapeutic agents acted synergistically to inhibit B16F10 cell proliferation. The greatest inhibition of cell proliferation was observed with the WT1-2/cisplatin (91%) and WT1-1/cisplatin combinations (85%). WT1 silencing using shRNAi induced the chemosensitization of cells to doxorubicin and cisplatin, with the greatest inhibition (85%) of cell proliferation being observed in the cells treated with the WT1-2/cisplatin 6 ng/µl combination. Our results provide direct evidence that WT1 gene silencing has a synergistic effect with chemotherapeutic drugs and sensitizes B16F10 melanoma cells to doxorubicin and cisplatin. This suggests that these combination strategies are potentially utilized in melanoma therapy.

Mouse mammary tumor virus-like gene sequences are present in lung patient specimens.

BACKGROUND: Previous studies have reported on the presence of Murine Mammary Tumor Virus (MMTV)-like gene sequences in human cancer tissue specimens. Here, we search for MMTV-like gene sequences in lung diseases including carcinomas specimens from a Mexican population. This study was based on our previous study reporting that the INER51 lung cancer cell line, from a pleural effusion of a Mexican patient, contains MMTV-like env gene sequences. RESULTS: The MMTV-like env gene sequences have been detected in three out of 18 specimens studied, by PCR using a specific set of MMTV-like primers. The three identified MMTV-like gene sequences, which were assigned as INER6, HZ101, and HZ14, were 99%, 98%, and 97% homologous, respectively, as compared to GenBank sequence accession number AY161347. The INER6 and HZ-101 samples were isolated from lung cancer specimens, and the HZ-14 was isolated from an acute inflammatory lung infiltrate sample. Two of the env sequences exhibited disruption of the reading frame due to mutations. CONCLUSION: In summary, we identified the presence of MMTV-like gene sequences in 2 out of 11 (18%) of the lung carcinomas and 1 out of 7 (14%) of acute inflamatory lung infiltrate specimens studied of a Mexican Population.

RNAi silencing of the WT1 gene inhibits cell proliferation and induces apoptosis in the B16F10 murine melanoma cell line.

The Wilms' tumor protein 1 (WT1) is essential for tumor cell proliferation and is highly expressed in various hematological and solid malignancies including human malignant melanoma. We investigated whether WT1 expression is essential for growth in the B16F10 murine melanoma cell line. Toward this end, we examined WT1 protein expression and WT1 isoforms (17AA+/17AA-, KTS+/KTS-) in this cell line. WT1 was silenced by two RNA interference constructs, designated WT1-1 and WT1-2. RNA interference-mediated reduction of WT1 protein expression significantly inhibited B16F10 cell viability. Loss of WT1 also increased caspase-3 and poly-ADP-ribose polymerase activation, as well as apoptotic body formation, chromatin condensation, and DNA fragmentation. Together, these findings implicate decreased WT1 protein levels in the induction of apoptosis. These results imply that WT1 plays a distinct role in B16F10 melanoma growth.

Seroprevalence of HTLV-I/II in blood donors in Monterrey, México

The prevalence of antibiodies against human T-cell lymphotrophic virus (HTLV-I/II) in blood donors from the city of Monterrey, Mexico was investigated. We found that 4 out of 1017 sera (0.39 percent) reacted against HTLV-I/II, as determined by a passive agglutination test (PA). However, none of PA-positive sere reacted to HTLV-I/II specific polypeptides as demostrated by Western blot. These findings indicate that the population of Monterry has very low or no seroprevalence for HTLV-I/II