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Cell Mol Life Sci ; 79(6): 309, 2022 May 21.
Article in English | MEDLINE | ID: covidwho-1919755


Blood clot formation induced by dysfunctional coagulation is a frequent complication of coronavirus disease 2019 (COVID-19) and a high-risk factor for severe illness and death. Neutrophil extracellular traps (NETs) are implicated in COVID-19-induced immunothrombosis. Furthermore, human cathelicidin, a NET component, can perturb the interaction between the SARS-CoV-2 spike protein and its ACE2 receptor, which mediates viral entry into cells. At present, however, the levels of cathelicidin antimicrobial peptides after SARS-CoV-2 infection and their role in COVID-19 thrombosis formation remain unclear. In the current study, we analyzed coagulation function and found a decrease in thrombin time but an increase in fibrinogen level, prothrombin time, and activated partial thromboplastin time in COVID-19 patients. In addition, the cathelicidin antimicrobial peptide LL-37 was upregulated by the spike protein and significantly elevated in the plasma of patients. Furthermore, LL-37 levels were negatively correlated with thrombin time but positively correlated with fibrinogen level. In addition to platelet activation, cathelicidin peptides enhanced the activity of coagulation factors, such as factor Xa (FXa) and thrombin, which may induce hypercoagulation in diseases with high cathelicidin peptide levels. Injection of cathelicidin peptides promoted the formation of thrombosis, whereas deletion of cathelicidin inhibited thrombosis in vivo. These results suggest that cathelicidin antimicrobial peptide LL-37 is elevated during SARS-CoV-2 infection, which may induce hypercoagulation in COVID-19 patients by activating coagulation factors.

Antimicrobial Cationic Peptides , COVID-19 , Thrombosis , Blood Coagulation Factors , COVID-19/complications , Fibrinogen , Humans , SARS-CoV-2 , Spike Glycoprotein, Coronavirus , Thrombosis/virology , Cathelicidins
Microbiol Spectr ; 9(1): e0026121, 2021 09 03.
Article in English | MEDLINE | ID: covidwho-1341309


The dynamics of quasispecies afford RNA viruses a great fitness on cell tropism and host range. To study the quasispecies features and the intra-host evolution of SARS-CoV-2, we collected nine confirmed patients and sequenced the haplotypes of spike gene using a single-molecule real-time platform. Fourteen samples were extracted from sputum, nasopharyngeal swabs, or stool, which in total produced 283,655 high-quality circular consensus sequences. We observed a stable quasispecies structure that one master mutant (mean abundance ∼0.70), followed by numerous minor mutants (mean abundance ∼1.21 × 10-3). Under high selective pressure, minor mutants may obtain a fitness advantage and become the master ones. The later predominant substitution D614G existed in the minor mutants of more than one early patient. An epidemic variant had a possibility to be independently originated from multiple hosts. The mutant spectrums covered ∼85% amino acid variations of public genomes (GISAID; frequency ≥ 0.1) and likely provided an advantage mutation pool for the current/future epidemic variants. Notably, 32 of 35 collected antibody escape substitutions were preexistent in the early quasispecies. Virus populations in different tissues/organs revealed potentially independent replications. The quasispecies complexity of sputum samples was significantly lower than that of nasopharyngeal swabs (P = 0.02). Evolution analysis revealed that three continuous S2 domains (HR1, CH, and CD) had undergone a positive selection. Cell fusion-related domains may play a crucial role in adapting to the intrahost immune system. Our findings suggested that future epidemiologic investigations and clinical interventions should consider the quasispecies information that has missed by routine single consensus genome. IMPORTANCE RNA virus population in a host does not consist of a consensus single haplotype but rather an ensemble of related sequences termed quasispecies. The dynamics of quasispecies afford SARS-CoV-2 a great ability on genetic fitness during intrahost evolution. The process is likely achieved by changing the genetic characteristics of key functional genes, such as the spike glycoprotein. Previous studies have applied the next-generation sequencing (NGS) technology to evaluate the quasispecies of SARS-CoV-2, and results indicated a low genetic diversity of the spike gene. However, the NGS platform cannot directly obtain the full haplotypes without assembling, and it is also difficult to predict the extremely low-frequency variations. Therefore, we introduced a single-molecule real-time technology to directly obtain the haplotypes of the RNA population and further study the quasispecies features and intrahost evolution of the spike gene.

Epidemics , Mutation , Quasispecies , SARS-CoV-2/classification , SARS-CoV-2/genetics , Adult , Aged , Base Sequence , COVID-19/virology , Child , Female , Genome, Viral , High-Throughput Nucleotide Sequencing , Humans , Male , Middle Aged , Spike Glycoprotein, Coronavirus/genetics
Virology ; 553: 131-134, 2021 01 15.
Article in English | MEDLINE | ID: covidwho-1059938


In patients coinfected with SARS-CoV-2 and HBV, liver injury was common. However, the interactions between SARS-CoV-2 and HBV coinfection remained unknown. Sixty-seven COVID-19 patients from the previous cohort were enrolled and classified into 2 groups (7 with HBsAg+ and 60 with HBsAg-). The association of HBV- and SARS-CoV-2-related markers were analyzed. During the acute course of SARS-CoV-2 infection, markers of HBV replication did not extensively fluctuate during SARS-CoV-2 infection. Coinfection with HBV did not extend the viral shedding cycle or incubation periods of SARS-CoV-2. Effects of SARS-CoV-2 on the dynamics of chronic HBV infection seemed not apparent. SARS-CoV-2 infection would not be the source of HBV reactivation in these individuals.

COVID-19/virology , Coinfection/virology , Hepatitis B, Chronic/virology , SARS-CoV-2 , Adult , Aged , Coinfection/drug therapy , Female , Hepatitis B, Chronic/drug therapy , Humans , Male , Middle Aged , Virus Activation , Virus Shedding , COVID-19 Drug Treatment