Biology subjects

Chow, V. T. K.

Publications and source records attributed to Chow, V. T. K..

3 recordsLinked to original sources

bioRxiv2023

Enterovirus-A71 exploits Rab11 to recruit chaperones for virus morphogenesis

Enterovirus 71 (EV-A71) causes Hand, Foot and Mouth Disease (HFMD) in children and has been associated with neurological complications. A siRNA screen in EV-A71 infected-motor neurons identified small GTPase Rab11a as a pro-viral host factor. Rab11a and Rab11b isoforms were interchangeably exploited by strains from major EV-A71 genogroups and Coxsackievirus 16, another major causative agent of HFMD. We showed that Rab11 did not play a role in viral entry, IRES-mediated protein translation, or viral genome replication, although it co-localized with replication organelles. GTPase-defective Rab11 mutants had no effect on EV-A71 replication, ruling out Rab11 involvement in intracellular trafficking of viral or host components. Instead, reduced VP2:VP0 ratio in siRab11-treated cells supported a role in provirion maturation. Co-immunoprecipitation and mass spectrometry revealed chaperones as Rab11 top interacting partners during infection. Among which, CCT8 subunit of the chaperone complex TRiC/CCT was found to interact with viral structural proteins specifically. Together, this study describes a novel, unconventional role for Rab11 during viral infection, where it participates in the complex process of virus morphogenesis by recruiting essential chaperone proteins.

microbiology↗

bioRxiv2020

Direct cleavage of human NLRP1 by enteroviral 3C protease triggers inflammasome activation in airway epithelium

Viruses pose a constant threat to human health. As a result our innate immune system has evolved multiple strategies to detect the presence of intracellular viral pathogen-associated molecular patterns (PAMPs) (1). The full repertoire of human immune sensors and their PAMP ligands are not completely understood. Here we report that human NLRP1 senses and is activated by 3C proteases (3Cpros) of enteroviruses. Mechanistically, 3Cpros cleave human NLRP1 at a single site immediately after its primate-specific PYRIN domain, leading to oligomerization of its C-terminal fragment. Expression of 3Cpros in primary human cells cause NLRP1-dependent ASC oligomerization, pyroptotic cell death and IL-1 secretion. Consistent with our observation that NLRP1 is the predominant endogenous inflammasome sensor in human airway epithelium, we find that its genetic deletion, or that of ASC, abrogates IL-18 secretion from rhinovirus (HRV)-infected primary human bronchial epithelial cells. Our findings identify the first cognate PAMP ligand for human NLRP1 and assign a new function for the NLRP1 inflammasome in human antiviral immunity and airway inflammation. These results challenge the widely held notion that viral proteases largely serve to disable host immune sensing, and suggest that the human NLRP1 inflammasome may be a therapeutic target to treat inflammatory airway diseases including asthma. One Sentence SummaryHuman NLRP1 is activated by enteroviral 3C proteases

immunology↗

bioRxiv2020

Monoclonal antibodies for the S2 subunit of spike of SARS-CoV cross-react with the newly-emerged SARS-CoV-2

The emergence of a novel coronavirus, SARS-CoV-2, at the end of 2019 has resulted in widespread human infections across the globe. While genetically distinct from SARS-CoV, the etiological agent that caused an outbreak of severe acute respiratory syndrome (SARS) in 2003, both coronaviruses exhibit receptor binding domain (RBD) conservation and utilize the same host cell receptor, angiotensin-converting enzyme 2 (ACE2), for virus entry. Therefore, it will be important to test the cross-reactivity of antibodies that have been previously generated against the surface spike (S) glycoprotein of SARS-CoV in order to aid research on the newly emerged SARS-CoV-2. Here, we show that an immunogenic domain in the S2 subunit of SARS-CoV S is highly conserved in multiple strains of SARS-CoV-2. Consistently, four murine monoclonal antibodies (mAbs) raised against this immunogenic SARS-CoV fragment were able to recognise the S protein of SARS-CoV-2 expressed in a mammalian cell line. Importantly, one of them (mAb 1A9) was demonstrated to detect S in SARS-CoV-2-infected cells. To our knowledge, this is the first study showing that mAbs targeting the S2 domain of SARS-CoV can cross-react with SARS-CoV-2 and this observation is consistent with the high sequence conservation in the S2 subunit. These cross-reactive mAbs may serve as tools useful for SARS-CoV-2 research as well as for the development of diagnostic assays for its associated coronavirus disease COVID-19.

microbiology↗