Biology subjects

Reid, S. P.

Publications and source records attributed to Reid, S. P..

6 recordsLinked to original sources

bioRxiv2020

Bromelain Inhibits SARS-CoV-2 Infection in VeroE6 Cells

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). The initial interaction between Transmembrane Serine Protease 2 (TMPRSS2) primed SARS-CoV-2 spike (S) protein and host cell receptor angiotensin-converting enzyme 2 (ACE-2) is a pre-requisite step for this novel coronavirus pathogenesis. Here, we expressed a GFP-tagged SARS-CoV-2 S-Ectodomain in Tni insect cells. That contained sialic acid-enriched N- and O-glycans. Surface resonance plasmon (SPR) and Luminex assay showed that the purified S-Ectodomain binding to human ACE-2 and immunoreactivity with COVID-19 positive samples. We demonstrate that bromelain (isolated from pineapple stem and used as a dietary supplement) treatment diminishes the expression of ACE-2 and TMPRSS2 in VeroE6 cells and dramatically lowers the expression of S-Ectodomain. Importantly, bromelain treatment reduced the interaction between S-Ectodomain and VeroE6 cells. Most importantly, bromelain treatment significantly diminished the SARS-CoV-2 infection in VeroE6 cells. Altogether, our results suggest that bromelain or bromelain rich pineapple stem may be used as an antiviral against COVID-19. Highlights O_FIG O_LINKSMALLFIG WIDTH=178 HEIGHT=200 SRC="FIGDIR/small/297366v1_ufig1.gif" ALT="Figure 1"> View larger version (35K): org.highwire.dtl.DTLVardef@b7afb0org.highwire.dtl.DTLVardef@16f8185org.highwire.dtl.DTLVardef@1a07df8org.highwire.dtl.DTLVardef@1ae33fa_HPS_FORMAT_FIGEXP M_FIG C_FIG O_LIBromelain inhibits / cleaves the expression of ACE-2 and TMPRSS2 C_LIO_LIBromelain cleaves / degrades SARS-CoV-2 spike protein C_LIO_LIBromelain inhibits S-Ectodomain binding and SARS-CoV-2 infection C_LI

microbiology↗

bioRxiv2020

Sphingosine Kinase 2 associates with the nsP3 of chikungunya virus and is required for replication

Sphingosine kinase 2 (SK2) is a lipid kinase that catalyzes the production of sphingosine-1-phosphate (S1P) from sphingosine. Previously, we have shown that SK2 is recruited to the viral replication complex (VRC) early during chikungunya virus (CHIKV) infection. In the present study, we demonstrate that SK2 is required for viral replication and protein production. Treatment with a SK2 inhibitor significantly impaired the function of a CHIKV replicon. Similarly, compound treatment or genetic targeting resulted in impaired viral protein production. Mechanistically, we demonstrate that CHIKV nsP3 binds to SK2. Association of nsP3 with SK2 was mediated, in part, through the FGDF motifs within the hypervariable domain (HVD) of nsP3. In a competition assay, SK2 competed with G3BP for binding to nsP3. Collectively, these results extend our previous findings and identify SK2 as a CHIKV host factor recruited by nsP3.

microbiology↗

bioRxiv2020

Chikungunya Virus Infection Impairs The Function Of Osteogenic Cells

Chikungunya virus (CHIKV) is a positive-sense, single-stranded RNA virus, spread by the Aedes species (sp.) mosquitoes. Chikungunya virus (CHIKV) causes a condition characterized by high fever, headache, rash, and joint pain. Recent investigations reveal presence of bone lesions and erosive arthritis in the joints of CHIKV infected patients, indicating an association of bone pathology with CHIKV infection. However, the molecular mechanism underlying CHIKV-induced bone pathology remains poorly defined. Bone marrow derived mesenchymal stem cells (BMSCs) contribute to bone homeostasis by differentiating into osteogenic cells which later mature to form the bone. Disruption of osteogenic differentiation and function of BMSCs lead to bone pathologies. Studies show that virus infections can alter the properties and function of BMSCs. However, to date, pathogenesis of CHIKV infection in this context has not been studied. In the current study, we investigated the susceptibility of BMSCs and osteogenic cells to CHIKV and studied the effect of infection on these cells. To our knowledge, for the first time we report that CHIKV can productively infect BMSCs and osteogenic cells. We also observed a decreased gene expression of the major regulator of osteogenic differentiation, RUNX2 in CHIKV infected osteogenic cells. Furthermore, impaired functional properties of osteogenic cells i.e. decreased production and activity of alkaline phosphatase (ALP) and matrix mineralization were observed in the presence of CHIKV infection. Thus, we conclude that CHIKV likely impairs osteogenic differentiation of BMSCs indicating a possible role of BMSCs in altering bone homeostasis during CHIKV infection. ImportancePresently, no vaccines or treatment options are available for CHIKV infection. Joint pain is one of the major concerns. Although studies have shown an association between bone pathology and infection, the molecular pathogenesis in context of bone pathology is poorly defined. Here, we demonstrate for the first time that BMSCs and BMSC-derived osteogenic cells are susceptible to CHIKV infection and infection likely alters function of the osteogenic cells. This study highlights altered osteogenic differentiation as a possible mechanism for causing the bone pathology observed in CHIKV pathogenesis.

microbiology↗

bioRxiv2019

Chikungunya virus infection impairs osteogenic differentiation of bone marrow-derived mesenchymal stem cells

Chikungunya virus (CHIKV) is a positive-sense, single-stranded RNA virus, belonging to the genus alphavirus in the family Togaviridae. The virus is spread by the Aedes species (sp.) mosquitoes in tropical and subtropical regions of the world. CHIKV causes Chikungunya fever (CHIKF), where the acute stage of infection is characterized by high fever, headache, rash, and polyarthralgia. In 30-40% of cases, patients develop a chronic stage with debilitating joint pain persisting for months to years imposing a burden on the population in terms of disability adjusted life years (DALY). Presently, no vaccines or treatment options are available for this infection. Prior investigations reveal that CHIKV infection is associated with bone pathology; however, the molecular mechanism underlying CHIKV-induced bone pathology remains poorly defined. Studies show that disruption of osteogenic differentiation and function of bone marrow-derived mesenchymal stem cells (BMMSCs) can lead to bone pathologies. However, to date pathogenesis of CHIKV infection in this context has not been studied. In the current study, we investigated the susceptibility of BMMSCs to CHIKV and studied the effect of infection on BMMSCs-derived osteogenic cells. To our knowledge, for the first time we report that CHIKV can productively infect BMMSCs. We observed a decrease in the intracellular and extracellular alkaline phosphatase (ALP) activity and reduction in calcium phosphate deposition in infected cells compared to mock-infected control. Thus, we conclude that CHIKV infects BMMSCs and disrupts function of osteogenic cells.\n\nImportanceAlthough studies have shown association of bone pathology and CHIKV infection, the pathogenesis of infection causing altered bone homeostasis is not fully understood. Here, we demonstrate for the first time that BMMSCs are susceptible to CHIKV infection. Furthermore, we observe that infection causes disruption in the function of BMMSC- derived osteogenic cells. Impaired function of these osteogenic cells will likely lead to a disruption in bone homeostasis and in part, provides a mechanism for the observed bone pathology associated with CHIKV pathogenesis.

microbiology↗

bioRxiv2019

Mutation of Ebola virus VP35 Ser129 uncouples interferon antagonist and replication functions

Ebolaviruses are non-segmented, negative-sense RNA viruses (NNSVs) within the order Mononegavirales that possess the multifunctional virion protein 35 (VP35), a major determinant of virulence and pathogenesis that is indispensable for viral replication and host innate immune evasion. VP35 is functionally equivalent to the phosphoprotein (P) of other mononegaviruses such as rhabdoviruses and paramyxoviruses. Phosphorylation of the P protein is universally regarded as functionally important however, a regulatory role(s) of phosphorylation on VP35 function remains unexplored. Here, we identified a highly conserved Ser129 residue near the homo-oligomerization coiled coil motif, which is essential for VP35 functions. Affinity-purification MS followed by post-translational modification (PTM) analysis predicted phosphorylation of Ser129. Co-immunoprecipitation, cross-linking, and biochemical characterization studies revealed a moderately decreased capacity of VP35-S129A to oligomerize. Functional analysis showed that Ser-to-Ala substitution of Ebola virus (EBOV) VP35 did not affect IFN inhibitory activity but nearly abolished EBOV minigenome activity. Further coimmunoprecipitation studies demonstrated a lost interaction between VP35-S129A and the amino terminus of the viral polymerase but not between viral nucleoprotein (NP) or VP35-WT. Taken together, our findings provide evidence that phosphorylation modulates VP35 function, supporting VP35 as a NNSV P protein and providing a potentially valuable therapeutic target.\n\nImportanceEbola virus (EBOV) can cause severe disease in humans. The 2013-2016 West African epidemic and the two recent outbreaks in the Democratic Republic of the Congo underscore the urgent need for effective countermeasures, which remain lacking. A better understanding of EBOV biology and the modulation of multifunctional viral proteins is desperately needed to develop improved therapeutics. We provide evidence here that function of virion protein 35 (VP35) is modulated by phosphorylation of Ser129, a conserved residue among other ebolavirus species. These findings shed light on EBOV biology and present a potential target for broad acting anti-ebolavirus therapeutics.

microbiology↗

bioRxiv2019

Glycosylation of Zika Virus Is Important in Host-Virus Interaction and Pathogenesis

Zika virus (ZIKV) is a global public health issue due to its association with severe developmental disorders in infants and neurological disorders in adults. Because ZIKV uses glycosylation of its envelope (E) protein to interact with host cell receptors to facilitate entry, these interactions could also be important for designing therapeutics and vaccines. Due to a lack of information about Asn-linked (N-glycans) on ZIKV E, we analyzed ZIKV E of various strains derived from different cells. ZIKV E proteins are extensively modified with oligomannose-, hybrid- and complex-N-glycans of a highly heterogeneous nature. Host cell-surface glycans correlated strongly with the glycomic features of ZIKV E. Mechanistically, we discovered that ZIKV N-glycans are important in viral pathogenesis, as mannose-specific C-type lectins DC-SIGN and L-SIGN mediate cell entry of ZIKV. Our findings represent the first detailed mapping of N-glycans on ZIKV E of various strains and their functional significance.

biochemistry↗