Kailang Wu

An outbreak of severe acute respiratory syndrome novel coronavirus (SARS-CoV-2) epidemic spreads rapidly worldwide. SARS-CoV-2 infection caused mildly to seriously and fatally respiratory, enteric, cardiovascular, and neurological diseases. In this study, we detected and analyzed the main laboratory indicators related to heart injury, creatine kinase isoenzyme-MB (CK-MB), myohemoglobin (MYO), cardiac troponin I (ultra-TnI), and N-terminal pro-brain natriuretic peptide (NT-proBNP), in 273 patients with COVID-19 and investigated the correlation between heart injury and severity of the disease. It was found that higher concentration in venous blood of CK-MB, MYO, ultra-TnI, and NT-proBNP were associated with the severity and case fatality rate of COVID-19. Careful monitoring of the myocardiac enzyme profiles is of great importance in reducing the complications and mortality in patients with COVID-19.

ABSTRACT Regulated gene expression and progeny production are essential for persistent and chronic infection by human pathogens, such as hepatitis B virus (HBV), which affects >400 million people worldwide and is a major cause of liver disease. In this study, we provide the first direct evidence that a liver‐specific microRNA, miR‐122, binds to a highly conserved HBV pregenomic RNA sequence via base‐pairing interactions and inhibits HBV gene expression and replication. The miR‐122 target sequence is located at the coding region of the mRNA for the viral polymerase and the 3' untranslated region of the mRNA for the core protein. In cultured cells, HBV gene expression and replication reduces with increased expression of miR‐122, and the expression of miR‐122 decreases in the presence of HBV infection and replication. Furthermore, analyses of clinical samples demonstrated an inverse linear correlation in vivo between the miR‐122 level and the viral loads in the peripheral blood mononuclear cells of HBV‐positive patients. Our results suggest that miR‐122 may down‐regulate HBV replication by binding to the viral target sequence, contributing to the persistent/chronic infection of HBV, and that HBV‐induced modulation of miR‐122 expression may represent a mechanism to facilitate viral pathogenesis.—Chen, Y., Shen, A., Rider, P. J., Yu, Y., Wu, K., Mu, Y., Hao, Q, Liu, Y., Gong, H., Zhu, Y., Liu, F., Wu, J. A liver‐specific microRNA binds to a highly conserved RNA sequence of hepatitis B virus and negatively regulates viral gene expression and replication. FASEB J. 25, 4511–4521 (2011). www.fasebj.org

Activation of NLRP3 inflammasome is important for effective host defense against invading pathogen. Together with apoptosis-associated speck-like protein containing CARD domain (ASC), NLRP3 induces the cleavage of caspase-1 to facilitate the maturation of interleukin-1beta (IL-1β), an important pro-inflammatory cytokine. IL-1β subsequently plays critical roles in inflammatory responses by activating immune cells and inducing many secondary pro-inflammatory cytokines. Although the role of NLRP3 inflammasome in immune response is well defined, the mechanism underlying its assembly modulated by pathogen infection remains largely unknown. Here, we identified a novel mechanism by which enterovirus 71 (EV71) facilitates the assembly of NLRP3 inflammasome. Our results show that EV71 induces production and secretion of IL-1β in macrophages and peripheral blood mononuclear cells (PBMCs) through activation of NLRP3 inflammasome. EV71 replication and protein synthesis are required for NLRP3-mediated activation of IL-1β. Interestingly, EV71 3D protein, a RNA-dependent RNA polymerase (RdRp) was found to stimulate the activation of NLRP3 inflammasome, the cleavage of pro-caspase-1, and the release of IL-1β through direct binding to NLRP3. More importantly, 3D interacts with NLRP3 to facilitate the assembly of inflammasome complex by forming a 3D-NLRP3-ASC ring-like structure, resulting in the activation of IL-1β. These findings demonstrate a new role of 3D as an important player in the activation of inflammatory response, and identify a novel mechanism underlying the modulation of inflammasome assembly and function induced by pathogen invasion.

How viruses evolve to select their receptor proteins for host cell entry is puzzling. We recently determined the crystal structures of NL63 coronavirus (NL63-CoV) and SARS coronavirus (SARS-CoV) receptor-binding domains (RBDs), each complexed with their common receptor, human angiotensin-converting enzyme 2 (hACE2), and proposed the existence of a virus-binding hot spot on hACE2. Here we investigated the function of this hypothetical hot spot using structure-guided biochemical and functional assays. The hot spot consists of a salt bridge surrounded by hydrophobic tunnel walls. Mutations that disturb the hot spot structure have significant effects on virus/receptor interactions, revealing critical energy contributions from the hot spot structure. The tunnel structure at the NL63-CoV/hACE2 interface is more compact than that at the SARS-CoV/hACE2 interface, and hence RBD/hACE2 binding affinities are decreased either by NL63-CoV mutations decreasing the tunnel space or by SARS-CoV mutations increasing the tunnel space. Furthermore, NL63-CoV RBD inhibits hACE2-dependent transduction by SARS-CoV spike protein, a successful application of the hot spot theory that has the potential to become a new antiviral strategy against SARS-CoV infections. These results suggest that the structural features of the hot spot on hACE2 were among the driving forces for the convergent evolution of NL63-CoV and SARS-CoV.