scholarly journals Lassa Virus Cell Entry via Dystroglycan Involves an Unusual Pathway of Macropinocytosis

2016 ◽  
Vol 90 (14) ◽  
pp. 6412-6429 ◽  
Author(s):  
Joel Oppliger ◽  
Giulia Torriani ◽  
Antonio Herrador ◽  
Stefan Kunz
Keyword(s):  
Antiviral Activity ◽  
Host Cell ◽  
Therapeutic Intervention ◽  
Kinase Inhibitors ◽  
Hemorrhagic Fever ◽  
Human Cells ◽  
New Drugs ◽  
High Rate ◽  
Actin Dynamics ◽  
Lassa Virus

ABSTRACTThe pathogenic Old World arenavirus Lassa virus (LASV) causes a severe hemorrhagic fever with a high rate of mortality in humans. Several LASV receptors, including dystroglycan (DG), TAM receptor tyrosine kinases, and C-type lectins, have been identified, suggesting complex receptor use. Upon receptor binding, LASV enters the host cell via an unknown clathrin- and dynamin-independent pathway that delivers the virus to late endosomes, where fusion occurs. Here we investigated the mechanisms underlying LASV endocytosis in human cells in the context of productive arenavirus infection, using recombinant lymphocytic choriomeningitis virus (rLCMV) expressing the LASV glycoprotein (rLCMV-LASVGP). We found that rLCMV-LASVGP entered human epithelial cells via DG using a macropinocytosis-related pathway independently of alternative receptors. Dystroglycan-mediated entry of rLCMV-LASVGP required sodium hydrogen exchangers, actin, and the GTPase Cdc42 and its downstream targets, p21-activating kinase-1 (PAK1) and Wiskott-Aldrich syndrome protein (N-Wasp). Unlike other viruses that enter cells via macropinocytosis, rLCMV-LASVGP entry did not induce overt changes in cellular morphology and hardly affected actin dynamics or fluid uptake. Screening of kinase inhibitors identified protein kinase C, phosphoinositide 3-kinase, and the receptor tyrosine kinase human hepatocyte growth factor receptor (HGFR) to be regulators of rLCMV-LASVGP entry. The HGFR inhibitor EMD 1214063, a candidate anticancer drug, showed antiviral activity against rLCMV-LASVGP at the level of entry. When combined with ribavirin, which is currently used to treat human arenavirus infection, EMD 1214063 showed additive antiviral effects. In sum, our study reveals that DG can link LASV to an unusual pathway of macropinocytosis that causes only minimal perturbation of the host cell and identifies cellular kinases to be possible novel targets for therapeutic intervention.IMPORTANCELassa virus (LASV) causes several hundred thousand infections per year in Western Africa, with the mortality rate among hospitalized patients being high. The current lack of a vaccine and the limited therapeutic options at hand make the development of new drugs against LASV a high priority. In the present study, we uncover that LASV entry into human cells via its major receptor, dystroglycan, involves an unusual pathway of macropinocytosis and define a set of cellular factors implicated in the regulation of LASV entry. A screen of kinase inhibitors revealed HGFR to be a possible candidate target for antiviral drugs against LASV. An HGFR candidate inhibitor currently being evaluated for cancer treatment showed potent antiviral activity and additive drug effects with ribavirin, which is used in the clinic to treat human LASV infection. In sum, our study reveals novel fundamental aspects of the LASV-host cell interaction and highlights a possible candidate drug target for therapeutic intervention.

scholarly journals Identification of a Broad-Spectrum Arenavirus Entry Inhibitor

2008 ◽  
Vol 82 (21) ◽  
pp. 10768-10775 ◽  
Author(s):  
Ryan A. Larson ◽  
Dongcheng Dai ◽  
Virginia T. Hosack ◽  
Ying Tan ◽  
Tove’ C. Bolken ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Viral Entry ◽  
Transmembrane Domain ◽  
Benzimidazole Derivative ◽  
Genetic Selection ◽  
Hemorrhagic Fever ◽  
Lymphocytic Choriomeningitis ◽  
Site Directed Mutagenesis ◽  
Lassa Virus ◽  
Carboxy Terminal

ABSTRACT Several arenaviruses, including Lassa virus (LASV), are causative agents of hemorrhagic fever, for which effective therapeutic options are lacking. The LASV envelope glycoprotein (GP) gene was used to generate lentiviral pseudotypes to identify small-molecule inhibitors of viral entry. A benzimidazole derivative with potent antiviral activity was identified from a high-throughput screen utilizing this strategy. Subsequent lead optimization for antiviral activity identified a modified structure, ST-193, with a 50% inhibitory concentration (IC50) of 1.6 nM against LASV pseudotypes. ST-193 inhibited pseudotypes generated with other arenavirus envelopes as well, including the remaining four commonly associated with hemorrhagic fever (IC50s for Junín, Machupo, Guanarito, and Sabiá were in the 0.2 to 12 nM range) but exhibited no antiviral activity against pseudotypes incorporating either the GP from the LASV-related arenavirus lymphocytic choriomeningitis virus (LCMV) or the unrelated G protein from vesicular stomatitis virus, at concentrations of up to 10 μM. Determinants of ST-193 sensitivity were mapped through a combination of LASV-LCMV domain-swapping experiments, genetic selection of viral variants, and site-directed mutagenesis. Taken together, these studies demonstrate that sensitivity to ST-193 is dictated by a segment of about 30 amino acids within the GP2 subunit. This region includes the carboxy-terminal region of the ectodomain and the predicted transmembrane domain of the envelope protein, revealing a novel antiviral target within the arenavirus envelope GP.

scholarly journals Cathepsin L plays a key role in SARS-CoV-2 infection in humans and humanized mice and is a promising target for new drug development

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Miao-Miao Zhao ◽  
Wei-Li Yang ◽  
Fang-Yuan Yang ◽  
Li Zhang ◽  
Wei-Jin Huang ◽  
...  
Keyword(s):  
Drug Development ◽  
Cathepsin L ◽  
Human Cells ◽  
New Drugs ◽  
Disease Course ◽  
Promising Target ◽  
First Time

AbstractTo discover new drugs to combat COVID-19, an understanding of the molecular basis of SARS-CoV-2 infection is urgently needed. Here, for the first time, we report the crucial role of cathepsin L (CTSL) in patients with COVID-19. The circulating level of CTSL was elevated after SARS-CoV-2 infection and was positively correlated with disease course and severity. Correspondingly, SARS-CoV-2 pseudovirus infection increased CTSL expression in human cells in vitro and human ACE2 transgenic mice in vivo, while CTSL overexpression, in turn, enhanced pseudovirus infection in human cells. CTSL functionally cleaved the SARS-CoV-2 spike protein and enhanced virus entry, as evidenced by CTSL overexpression and knockdown in vitro and application of CTSL inhibitor drugs in vivo. Furthermore, amantadine, a licensed anti-influenza drug, significantly inhibited CTSL activity after SARS-CoV-2 pseudovirus infection and prevented infection both in vitro and in vivo. Therefore, CTSL is a promising target for new anti-COVID-19 drug development.

scholarly journals Lassa Virus Circulation in Small Mammal Populations in Bo District, Sierra Leone

Biology ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 28
Author(s):  
Umaru Bangura ◽  
Jacob Buanie ◽  
Joyce Lamin ◽  
Christopher Davis ◽  
Gédéon Ngiala Bongo ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Sierra Leone ◽  
Small Mammal ◽  
Hemorrhagic Fever ◽  
Lassa Fever ◽  
Lassa Virus ◽  
Sierra Leonean ◽  
Bayesian Phylogenetic Analysis ◽  
Prevalent Species ◽  
Lineage Iv

Lassa fever is a viral hemorrhagic fever caused by the Lassa virus LASV, which was first isolated in the rodent Mastomys natalensis in 1974 in Kenema, Sierra Leone. As little is known about the abundance and the presence of LASV in rodents living in the Bo area, we carried out a small mammal longitudinal population survey. A standardized trapping session was performed in various habitats and seasons in six villages over two years (2014–2016) and samples collected were tested for arenavirus IgG and LASV. A Bayesian phylogenetic analysis was performed on sequences identified by PCR. A total of 1490 small mammals were collected, and 16 rodent species were identified, with M. natalensis (355, 24%) found to be the most prevalent species. Forty-one (2.8%) samples were IgG positive, and 31 of these were trapped in homes and 10 in surrounding vegetation. Twenty-nine of 41 seropositive rodents were M. natalensis. We detected four LASV by PCR in two villages, all found in M. natalensis. Phylogenetic analysis showed that the sequences were distributed within the Sierra Leonean clade within lineage IV, distinguishing a Bo sub-clade older than a Kenema sub-clade. Compared to other settings, we found a low abundance of M. natalensis and a low circulation of LASV in rodents in villages around Bo district.

Treatment outcomes of recurrent and metastatic adenoid cystic carcinoma: A retrospective analysis.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. e18056-e18056
Author(s):  
Julie Elaine McGrath ◽  
Punita Grover ◽  
Joanne Xiu ◽  
Chadi Nabhan ◽  
Jennifer Hsing Choe ◽  
...  
Keyword(s):  
Overall Survival ◽  
Adenoid Cystic Carcinoma ◽  
Real World ◽  
Kinase Inhibitors ◽  
Checkpoint Inhibitors ◽  
Predictive Biomarkers ◽  
High Rate ◽  
Entire Cohort ◽  
Adenoid Cystic ◽  
Significant Difference

e18056 Background: Adenoid cystic carcinoma (ACC) is a rare malignancy of glandular tissue with a high rate of local recurrence and metastatic disease. Despite being regarded as an indolent disease, the clinical course of recurrent and metastatic ACC (R/M ACC) is highly variable. Responses to chemotherapy (chemo) are uniformly poor. Several multi-targeted tyrosine-kinase inhibitors (mTKIs), EGFR inhibitors (EGFRi) and other targeted agents have been studied in single-arm early phase trials with response rates ranging from 0-16% and progression free survival ranging from 2.5-17 months. However, there have been no comparative clinical trials and it is not known if one treatment strategy is superior. We undertook this retrospective study to assess the real-world clinical outcomes in patients with adenoid cystic carcinoma using the Caris Life Sciences database. Methods: Real world overall survival (rwOS) for cases of ACC was obtained from insurance claims data and Kaplan-Meier estimates were calculated from the date of collection to the date of last contact. Cases were divided into subgroups based on treatment received – chemo (including platinum agents, taxanes, 5FU, topoisomerase inhibitors, anthracyclines), EGFRi (cetuximab, erlotinib, lapatinib), mTKIs (pazopanib, axitinib, sunitinib, cabozantinib, lenvatinib, sorafenib) and immune checkpoint inhibitors (ICIs) (atezolizumab, ipilimumab, pembrolizumab, nivolumab). Results: 368 patients (pts) were identified with ACC, 16 were locally recurrent and 216 tumors were taken from metastatic sites. 50 pts received chemo, 6 were treated with EGFRi and 15 with mTKIs. Pts who received combination EGFRi and chemo or mTKI and chemo were excluded. The median overall survival (mOS) all patients with metastatic ACC was 2.8 years (yrs). The mOS of pts with R/M ACC was 3 yrs for chemo, 2.9 yrs for EGFRi and 1.5 yrs for mTKIs. There was no significance in mOS between chemo vs mTKIs (HR 0.85, 95% CI 0.3 - 2, p = 0.72) and chemo vs EGFRi (HR = 0.88, 95% CI 0.3 - 2.5, p = 0.78). We further compared the outcomes of those treated with EGFRi (n = 8) with mTKIs (n = 19) in the entire cohort. For most pts, these agents were given as front line therapy. 25% (2/8) of patients had received treatment prior to EGFRi and 20% (4/9) prior to mTKIs (p = 1). There was no significant difference in mOS with HR 0.6 (95% CI 0.16 - 2.6), p = 0.6. We also compared the mOS of patients who received ICIs (n = 22) with those who did not (n = 346) but there was no significant difference (mOS 3.19 vs 3.17 yrs respectively, HR 0.87, 95% CI 0.47- 1.61, p = 0.65). Conclusions: There was no significant difference in the mOS between pts with R/M ACC who were treated with chemo, EGFRi or TKIs and in those who received ICIs compared to those who did not in our limited patient population. This highlights the need for predictive biomarkers for better patient selection with the goal of personalizing treatment strategies for this disease.

Lassa hemorrhagic fever model using new generalized Caputo-type fractional derivative operator

2021 ◽  
pp. 2150055
Author(s):  
Pushpendra Kumar ◽  
Vedat Suat Erturk ◽  
Abdullahi Yusuf ◽  
Tukur Abdulkadir Sulaiman
Keyword(s):  
Pregnant Women ◽  
Fractional Order ◽  
Research Work ◽  
Hemorrhagic Fever ◽  
Hemorrhagic Disease ◽  
Lassa Virus ◽  
Research Fields ◽  
Negative Impacts ◽  
Predictor Corrector ◽  
The Given

In some of the previous decades, we have observed that mathematical modeling has become one of the most interesting research fields and has attracted many researchers. In this regard, thousands of researchers have proposed different varieties of mathematical models to study the dynamics of a number of real-world problems. This research work is framed to analyzing the structure of the well-known Lassa hemorrhagic epidemic; a dangerous epidemic for pregnant women, via new generalized Caputo type noninteger order derivative with the help of a modified Predictor–Corrector scheme. Lassa hemorrhagic disease is an epidemical and biocidal fever, whose negative impacts were initially recognized in the countries of Africa. This virus has killed many pregnant women as compared to the Ebola epidemic. It was noticed that Lassa virus was isolated in Vero cell cultures from a blood pattern, and after 12 days it was ejective, after the climb of the sickness. In this research study, necessary theorems and lemmas are reminded to prove the existence of a unique solution and stability of given fractional approximation scheme. All necessary results are reminded to confirm the effectiveness of the proposed approximation algorithm by graphical observations for various fractional-order values. In our practical calculations, we plotted the graphs for two different values of natural death rate along with various values of given fractional-order operator. Our major target is to show the importance of the proposed modified version of the Predictor–Corrector algorithm in epidemic studies by exploring the given Lassa hemorrhagic fever dynamics.

scholarly journals The effectiveness of antiviral agents with broad-spectrum activity against chikungunya virus varies between host cell lines

2018 ◽  
Vol 26 ◽  
pp. 204020661880758 ◽  
Author(s):  
Evelyn J Franco ◽  
Jaime L Rodriquez ◽  
Justin J Pomeroy ◽  
Kaley C Hanrahan ◽  
Ashley N Brown
Keyword(s):  
Antiviral Activity ◽  
Host Cell ◽  
Cell Line ◽  
Cell Lines ◽  
Broad Spectrum ◽  
Chikungunya Virus ◽  
Plaque Assay ◽  
A549 Cells ◽  
Western Hemisphere ◽  
Viral Burden

Chikungunya virus (CHIKV) is a mosquito-borne virus that has recently emerged in the Western Hemisphere. Approved antiviral therapies or vaccines for the treatment or prevention of CHIKV infections are not available. This study aims to evaluate the antiviral activity of commercially available broad-spectrum antivirals against CHIKV. Due to host cell-specific variability in uptake and intracellular processing of drug, we evaluated the antiviral effects of each agent in three cell lines. Antiviral activities of ribavirin (RBV), interferon-alfa (IFN-α) and favipiravir (FAV) were assessed in CHIKV-infected Vero, HUH-7, and A549 cells. CHIKV-infected cells were treated with increasing concentrations of each agent for three days and viral burden was quantified by plaque assay on Vero cells. Cytotoxic effects of RBV, FAV and IFN-α were also evaluated. Antiviral activity differed depending on the cell line used for evaluation. RBV had the greatest antiviral effect in HUH-7 cells (EC50 = 2.575 µg/mL); IFN-α was most effective in A549 cells (EC50 = 4.235 IU/mL); and FAV in HUH-7 cells (EC50 = 20.00 μg/mL). The results of our study show FAV and IFN-α are the most promising candidates, as their use led to substantial reductions in viral burden at clinically achievable concentrations in two human-derived cell lines. FAV is an especially attractive candidate for further investigation due to its oral bioavailability. These findings also highlight the importance of cell line selection for preclinical drug trials.

scholarly journals Subversion of the Heme Oxygenase-1 Antiviral Activity by Zika Virus

Viruses ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 2 ◽  
Author(s):  
Chaker El Kalamouni ◽  
Etienne Frumence ◽  
Sandra Bos ◽  
Jonathan Turpin ◽  
Brice Nativel ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Heme Oxygenase ◽  
Zika Virus ◽  
Fluorescent Protein ◽  
Human Cells ◽  
Heme Oxygenase 1 ◽  
Viral Inhibition ◽  
Reporter Protein ◽  
Wide Range ◽  
Rna Replicon

Heme oxygenase-1 (HO-1), a rate-limiting enzyme involved in the degradation of heme, is induced in response to a wide range of stress conditions. HO-1 exerts antiviral activity against a broad range of viruses, including the Hepatitis C virus, the human immunodeficiency virus, and the dengue virus by inhibiting viral growth. It has been reported that HO-1 displays antiviral activity against the Zika virus (ZIKV) but the mechanisms of viral inhibition remain largely unknown. Using a ZIKV RNA replicon with the Green Fluorescent Protein (GFP) as a reporter protein, we were able to show that HO-1 expression resulted in the inhibition of viral RNA replication. Conversely, we observed a decrease in HO-1 expression in cells replicating the ZIKV RNA replicon. The study of human cells infected with ZIKV showed that the HO-1 expression level was significantly lower once viral replication was established, thereby limiting the antiviral effect of HO-1. Our work highlights the capacity of ZIKV to thwart the anti-replicative activity of HO-1 in human cells. Therefore, the modulation of HO-1 as a novel therapeutic strategy against ZIKV infection may display limited effect.

scholarly journals Stampidine prevents mortality in an experimental mouse model of viral hemorrhagic fever caused by lassa virus

2004 ◽  
Vol 4 (1) ◽  
Author(s):  
Fatih M Uckun ◽  
Alexander S Petkevich ◽  
Alexei O Vassilev ◽  
Heather E Tibbles ◽  
Leonid Titov
Keyword(s):  
Mouse Model ◽  
Hemorrhagic Fever ◽  
Lassa Virus ◽  
Viral Hemorrhagic Fever ◽  
Experimental Mouse Model ◽  
Experimental Mouse

scholarly journals Identification of anti-norovirus genes in mouse and human cells using genome-wide CRISPR activation screening

2018 ◽  
Author(s):  
Robert C. Orchard ◽  
Meagan E. Sullender ◽  
Bria F. Dunlap ◽  
Dale R. Balce ◽  
John G. Doench ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
World Wide ◽  
Human Cells ◽  
Gene Promoters ◽  
Murine Norovirus ◽  
Individual Gene ◽  
Genome Wide ◽  
Host Genes ◽  
Crispr Activation

AbstractNoroviruses (NoVs) are a leading cause of gastroenteritis world-wide, yet host factors that restrict NoV replication are not well understood. Here, we use a CRISPR activation (CRISPRa) genome-wide screening to identify host genes that can inhibit murine norovirus (MNoV) replication in either mouse or human cells. Our screens identified with high confidence 57 genes that can inhibit MNoV infection when overexpressed. A significant number of these genes are in interferon and immune regulation signaling networks, but surprising, the majority of the genes identified are not associated with innate or adaptive immunity nor with any antiviral activity. Confirmatory studies of eight of the genes in validate the initial screening data. Mechanistic studies on TRIM7 demonstrated a conserved role of the molecule in mouse and human cells in restricting MNoV in a step of infection after viral entry. Furthermore, we demonstrate that two isoforms of TRIM7 have differential antiviral activity. Taken together these data provide a resource for understanding norovirus biology and demonstrate a robust methodology for identifying new antiviral molecules across cell types and species.Author SummaryNorovirus is one of the leading causes of foodborne illness world-wide. Despite its prevalence, our understanding of norovirus biology is limited due to the difficulty in growing human norovirus in vitro and a lack of an animal model. Murine norovirus (MNoV) is a model norovirus system because MNoV replicates robustly in cell culture and in mice. To identify host genes that can restrict norovirus replication when overexpressed we performed genome-wide CRISPR activation (CRISPRa) screens to induce gene overexpression at the native locus through recruitment of transcriptional activators to individual gene promoters. We found 57 genes could block murine norovirus replication in either mouse or human cells. Several of these genes are associated with classical immune signaling pathways, while many of the molecules we identified have not been previously associated with antiviral activity. Our data is a resource for those studying norovirus and we provide a robust approach to identify novel antiviral genes.

scholarly journals Advanced melanoma, a pharmacological evaluation

2021 ◽  
Vol 31 (Supplement_2) ◽  
Author(s):  
Anabela Andrade ◽  
Jorge Balteiro
Keyword(s):  
Overall Survival ◽  
Targeted Therapy ◽  
Braf Inhibitor ◽  
Progression Free Survival ◽  
Mek Inhibitor ◽  
Advanced Melanoma ◽  
New Drugs ◽  
High Rate ◽  
Free Survival ◽  
Dismal Prognosis

Abstract Background Cutaneous melanoma is an aggressive cancer that occurs in melanocytes, located in the epidermis. Historically it has a high rate of morbidity and mortality, due to the resistance and toxicity of traditional therapies. Its incidence has increased annually by 4% to 8%. Until 2011 it was still considered a devastating and almost always fatal disease in a few months. Advances in therapies have significantly improved the results of most patients with advanced melanoma, especially those with a BRAFV600 mutation, which account for almost 50% of tumors. Before the recent evolution in treatment, the prognosis and overall survival were considered very bad. The introduction of new drugs has improved progression-free survival and overall survival, as well as producing faster clinical responses. Methods Comparison of endpoints such as progression-free survival and overall melanoma survival from the Summary of Product Characteristics (SPC) studies of each drug in the therapeutic groups under assessment used in the disease. The variables used were the Endpoints Global Survival at various times (12 months, 24 months, 36 months and the median) and Progression-Free Survival. Results Combined immunotherapy (Nivolumab and Ipilimumab) improves overall survival and progression-free survival, achieving better results than targeted therapy. In this, the combination of a BRAF inhibitor and a MEK inhibitor, presents better results with the combination of Encorafenib and Binimetinib. Conclusions Both targeted therapy and immunotherapy transform melanoma with a dismal prognosis into a life-threatening illness.

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