The twenty-first century has already recorded more than ten major epidemics or pandemics of viral disease, including the devastating COVID-19. Novel effective antivirals with broad-spectrum coverage are urgently needed. Herein, we reported a novel broad-spectrum antiviral compound PAC5. Oral administration of PAC5 eliminated HBV cccDNA and reduced the large antigen load in distinct mouse models of HBV infection. Strikingly, oral administration of PAC5 in a hamster model of SARS-CoV-2 omicron (BA.1) infection significantly decreases viral loads and attenuates lung inflammation. Mechanistically, PAC5 binds to a pocket near Asp49 in the RNA recognition motif of hnRNPA2B1. PAC5-bound hnRNPA2B1 is extensively activated and translocated to the cytoplasm where it initiates the TBK1-IRF3 pathway, leading to the production of type I IFNs with antiviral activity. Our results indicate that PAC5 is a novel small-molecule agonist of hnRNPA2B1, which may have a role in dealing with emerging infectious diseases now and in the future.
Animals ; Mice ; Antiviral Agents/pharmacology* ; COVID-19 ; Hepatitis B virus ; Interferon Type I/metabolism* ; SARS-CoV-2/drug effects* ; Heterogeneous-Nuclear Ribonucleoprotein Group A-B/antagonists & inhibitors*

Objective To explore the effects and mechanisms of a traditional Chinese medicine (TCM) prescription, "Fang-gan Decoction" (FGD), in protecting against SARS-CoV-2 spike protein-induced lung and intestinal injuries in vitro and in vivo.Methods Female BALB/c mice and three cell lines pretreated with FGD were stimulated with recombinant SARS-CoV-2 spike protein (spike protein). Hematoxylin-eosin (HE) staining and pathologic scoring of tissues, cell permeability and viability, and angiotensin-converting enzyme 2 (ACE2) expression in the lung and colon were detected. Enzyme-linked immunosorbent assay (ELISA) was performed to detect the levels of inflammatory factors in serum and cell supernatant. The expression of NF-κB p65, p-NF-κB p65, p-IκBα, p-Smad2/3, TGF-β1, Caspase3, and Bcl-2 was evaluated by Western blotting.Results FGD protected against the damage to the lung and colon caused by the spike protein in vivo and in vitro according to the pathologic score and cell permeability and viability (P<0.05). FGD up-regulated ACE2 expression, which was reduced by the spike protein in the lung and colon, significantly improved the deregulation of inflammatory markers caused by the spike protein, and regulated the activity of TGF-β/Smads and NF-κB signaling.Conclusion Traditional Chinese medicine has a protective effect on lung and intestinal tissue injury stimulated by the spike protein through possible regulatory functions of the NF-κB and TGF-β1/Smad pathways with tissue type specificity.
Mice ; Animals ; Female ; Humans ; NF-kappa B/metabolism* ; Spike Glycoprotein, Coronavirus/pharmacology* ; Transforming Growth Factor beta1/metabolism* ; Angiotensin-Converting Enzyme 2/pharmacology* ; COVID-19 ; SARS-CoV-2/metabolism* ; Lung ; Antineoplastic Agents ; Transforming Growth Factor beta/pharmacology* ; Epithelial Cells/metabolism* ; Colon

新冠病毒感染疫情严重威胁着世界各国人民的生命健康。目前，对病毒感染的防治研究主要集中在抑制病毒与分子受体的结合上。AXL作为新发现的严重急性呼吸综合征冠状病毒2型（SARS-CoV-2）受体，在协助病毒感染人体呼吸系统中发挥着重要作用，是未来临床干预的潜在靶点。本研究对已发表的单细胞测序数据进行整理和分析，发现AXL在年轻人肺细胞中的表达水平明显高于老年人。人胚肺二倍体成纤维细胞（2BS）是衰老研究的公认细胞株。本文采用2BS细胞构建复制性细胞衰老模型，发现年轻细胞中AXL的蛋白水平明显高于衰老细胞，据此推测年轻人感染的风险可能更高，需要注意防护。我们发现一种羊栖菜褐藻多糖硫酸酯组分（SFW-3）可显著下调年轻2BS细胞中AXL的表达水平，表明SFW-3具有一定的抗SARS-CoV-2感染的研究价值，同时表明2BS细胞株也可作为潜在的SARS-CoV-2体外感染模型。
Humans ; SARS-CoV-2 ; Sargassum/metabolism* ; Diploidy ; Sulfates/metabolism* ; COVID-19 ; Polysaccharides/pharmacology* ; Lung

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has affected 660 million people and resulted in 6.7 million deaths. At present, a variety of risk factors related to the severity of COVID-19 have been identified, but whether allergic rhinitis and asthma will affect SARS-CoV-2 infection remains controversial. In general, there is no sufficient evidence to support that allergic rhinitis or asthma is a risk factor for increasing the rate of SARS-CoV-2 infection or aggravating the disease. Some studies even show that atopy may be a protective factor to alleviate SARS-CoV-2 infection, which is related to the decreased expression of angiotensin-converting enzyme 2, the receptor required for SARS-CoV-2 to enter cells, in atopic individuals. This paper reviews the influence of the severity and treatment of allergic rhinitis and asthma on SARS-CoV-2 infection, in order to provide some references for establishing strategies for prevention, risk stratification and treatment of COVID-19.
Humans ; COVID-19 ; SARS-CoV-2/metabolism* ; Peptidyl-Dipeptidase A/metabolism* ; Asthma/therapy* ; Rhinitis, Allergic

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has affected 660 million people and resulted in 6.7 million deaths. At present, a variety of risk factors related to the severity of COVID-19 have been identified, but whether allergic rhinitis and asthma will affect SARS-CoV-2 infection remains controversial. In general, there is no sufficient evidence to support that allergic rhinitis or asthma is a risk factor for increasing the rate of SARS-CoV-2 infection or aggravating the disease. Some studies even show that atopy may be a protective factor to alleviate SARS-CoV-2 infection, which is related to the decreased expression of angiotensin-converting enzyme 2, the receptor required for SARS-CoV-2 to enter cells, in atopic individuals. This paper reviews the influence of the severity and treatment of allergic rhinitis and asthma on SARS-CoV-2 infection, in order to provide some references for establishing strategies for prevention, risk stratification and treatment of COVID-19.
Humans ; COVID-19 ; SARS-CoV-2/metabolism* ; Peptidyl-Dipeptidase A/metabolism* ; Asthma/therapy* ; Rhinitis, Allergic

COVID-19 represents the most serious public health event in the past few decades of the 21^st century. The development of vaccines, neutralizing antibodies, and small molecule chemical agents have effectively prevented the rapid spread of COVID-19. However, the continued emergence of SARS-CoV-2 variants have weakened the efficiency of these vaccines and antibodies, which brought new challenges for searching novel anti-SARS-CoV-2 drugs and methods. In the process of SARS-CoV-2 infection, the virus firstly attaches to heparan sulphate on the cell surface of respiratory tract, then specifically binds to hACE2. The S protein of SARS-CoV-2 is a highly glycosylated protein, and glycosylation is also important for the binding of hACE2 to S protein. Furthermore, the S protein is recognized by a series of lectin receptors in host cells. These finding implies that glycosylation plays important roles in the invasion and infection of SARS-CoV-2. Based on the glycosylation pattern and glycan recognition mechanisms of SARS-CoV-2, it is possible to develop glycan inhibitors against COVID-19. Recent studies have shown that sulfated polysaccharides originated from marine sources, heparin and some other glycans display anti-SARS-CoV-2 activity. This review summarized the function of glycosylation of SARS-CoV-2, discoveries of glycan inhibitors and the underpinning molecular mechanisms, which will provide guidelines to develop glycan-based new drugs against SARS-CoV-2.
Antibodies, Neutralizing ; Glycosylation ; Heparin ; Heparitin Sulfate ; Humans ; Polysaccharides/chemistry* ; Receptors, Mitogen/metabolism* ; SARS-CoV-2 ; Spike Glycoprotein, Coronavirus/metabolism* ; COVID-19 Drug Treatment

Coronavirus disease (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), with strong contagiousness, high susceptibility and long incubation period. cell entry by SARS-CoV-2 requires the binding between the receptor-binding domain of the viral spike protein and the cellular angiotensin-converting enzyme 2 (ACE2). Here, we briefly reviewed the mechanisms underlying the interaction between SARS-CoV-2 and ACE2, and summarized the latest research progress on SARS-CoV-2 neutralizing monoclonal antibodies and nanobodies, so as to better understand the development process and drug research direction of COVID-19. This review may facilitate understanding the development of neutralizing antibody drugs for emerging infectious diseases, especially for COVID-19.
Angiotensin-Converting Enzyme 2 ; Antibodies, Monoclonal ; Antibodies, Neutralizing ; Antibodies, Viral ; COVID-19 ; Humans ; Peptidyl-Dipeptidase A/metabolism* ; Protein Binding ; SARS-CoV-2 ; Single-Domain Antibodies ; Spike Glycoprotein, Coronavirus/metabolism*

The nucleocapsid (N) protein of SARS-CoV-2 has been reported to have a high ability of liquid-liquid phase separation, which enables its incorporation into stress granules (SGs) of host cells. However, whether SG invasion by N protein occurs in the scenario of SARS-CoV-2 infection is unknow, neither do we know its consequence. Here, we used SARS-CoV-2 to infect mammalian cells and observed the incorporation of N protein into SGs, which resulted in markedly impaired self-disassembly but stimulated cell cellular clearance of SGs. NMR experiments further showed that N protein binds to the SG-related amyloid proteins via non-specific transient interactions, which not only expedites the phase transition of these proteins to aberrant amyloid aggregation in vitro, but also promotes the aggregation of FUS with ALS-associated P525L mutation in cells. In addition, we found that ACE2 is not necessary for the infection of SARS-CoV-2 to mammalian cells. Our work indicates that SARS-CoV-2 infection can impair the disassembly of host SGs and promote the aggregation of SG-related amyloid proteins, which may lead to an increased risk of neurodegeneration.
Amyloidogenic Proteins/metabolism* ; Amyotrophic Lateral Sclerosis/genetics* ; Animals ; COVID-19 ; Cytoplasmic Granules/metabolism* ; Mammals ; SARS-CoV-2 ; Stress Granules

OBJECTIVE: Jingfang Granules have been recommended for the prevention and treatment of corona virus disease 2019 (COVID-19). Through chemical analysis and bioactivity evaluation, this study aims to elucidate the potential effective components of Jingfang Granules. METHODS: The inhibitory acti-vities of Jingfang Granules extract against 3-chymotrypsin-like protease (3CL^pro), papain like protease (PL^pro), spike protein receptor-binding domain (S-RBD) and human cyclooxygenase-2 (COX-2) were evaluated using enzyme assay. The antitussive effects were evaluated using the classical ammonia-induced cough model. The chemical constituents of Jingfang Granules were qualitatively and quantitatively analyzed by liquid chromatography-mass spectrometry (LC/MS). The 3CL^pro and PL^pro inhibitory activities of the major compounds were determined by enzyme assay, molecular docking, and site-directed mutagenesis. RESULTS: Jingfang Granules exhibited 3CL^pro and PL^pro inhibitory activities, as well as COX-2 inhibitory and antitussive activities. By investigating the MS/MS behaviors of reference standards, a total of fifty-six compounds were characterized in Jingfang Granules. Sixteen of them were unambiguously identified by comparing with reference standards. The contents of the 16 major compounds were also determined, and their total contents were 2 498.8 μg/g. Naringin, nodakenin and neohesperidin were three dominating compounds in Jingfang Granules, and their contents were 688.8, 596.4 and 578.7 μg/g, respectively. In addition, neohesperidin and naringin exhibited PL^pro inhibitory activities, and the inhibition rates at 8 μmol/L were 53.5% and 46.1%, respectively. Prim-O-glucosylcimifugin showed significant inhibitory activities against 3CL^pro and PL^pro, and the inhibitory rates at 8 μmol/L were 76.8% and 78.2%, respectively. Molecular docking indicated that hydrogen bonds could be formed between prim-O-glucosylcimifugin and amino acid residues H163, E166, Q192, T190 of 3CL^pro (binding energy, -7.7 kcal/mol) and K157, D164, R166, E167, T301 of PL^pro(-7.3 kcal/mol), respectively. Site-directed mutagenesis indicated amino acid residue K157 was a key active site for the interaction between prim-O-glucosylcimifugin and PL^pro. CONCLUSION Prim-O-glucosylcimifugin, neohesperidin, and naringin as the major compounds from Jingfang Granules could inhibit severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus proteases 3CL^pro and PL^pro. The results are valuable for rational clinical use of Jingfang Granules.
Amino Acids ; Ammonia ; Antitussive Agents ; COVID-19 ; Chymases ; Coronavirus 3C Proteases ; Cyclooxygenase 2 ; Cyclooxygenase 2 Inhibitors ; Cysteine Endopeptidases/metabolism* ; Humans ; Molecular Docking Simulation ; Papain ; Peptide Hydrolases ; SARS-CoV-2 ; Spike Glycoprotein, Coronavirus ; Tandem Mass Spectrometry

Adenosine diphosphate (ADP)-ribosylation is a unique post-translational modification that regulates many biological processes, such as DNA damage repair. During DNA repair, ADP-ribosylation needs to be reversed by ADP-ribosylhydrolases. A group of ADP-ribosylhydrolases have a catalytic domain, namely the macrodomain, which is conserved in evolution from prokaryotes to humans. Not all macrodomains remove ADP-ribosylation. One set of macrodomains loses enzymatic activity and only binds to ADP-ribose (ADPR). Here, we summarize the biological functions of these macrodomains in DNA damage repair and compare the structure of enzymatically active and inactive macrodomains. Moreover, small molecular inhibitors have been developed that target macrodomains to suppress DNA damage repair and tumor growth. Macrodomain proteins are also expressed in pathogens, such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, these domains may not be directly involved in DNA damage repair in the hosts or pathogens. Instead, they play key roles in pathogen replication. Thus, by targeting macrodomains it may be possible to treat pathogen-induced diseases, such as coronavirus disease 2019 (COVID-19).
ADP-Ribosylation ; COVID-19/metabolism* ; DNA Repair/physiology* ; Evolution, Molecular ; Humans ; Models, Biological ; Models, Molecular ; N-Glycosyl Hydrolases/metabolism* ; Poly(ADP-ribose) Polymerases/metabolism* ; Protein Domains ; SARS-CoV-2/pathogenicity*