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The SARS-CoV-2 coronavirus, the etiologic agent of COVID-19, uses its spike (S) glycoprotein anchored in the viral membrane to enter host cells. The S glycoprotein is the major target for neutralizing antibodies elicited by natural infection and by vaccines. Approximately 35% of the SARS-CoV-2 S glycoprotein consists of carbohydrate, which can influence virus infectivity and susceptibility to antibody inhibition. We found that virus-like particles produced by coexpression of SARS-CoV-2 S, M, E and N proteins contained spike glycoproteins that were extensively modified by complex carbohydrates. We used a fucose-selective lectin to enrich the Golgi-resident fraction of a wild-type SARS-CoV-2 S glycoprotein trimer, and determined its glycosylation and disulfide bond profile. Compared with soluble or solubilized S glycoproteins modified to prevent proteolytic cleavage and to retain a prefusion conformation, more of the wild-type S glycoprotein N-linked glycans are processed to complex forms. Even Asn 234, a significant percentage of which is decorated by high-mannose glycans on soluble and virion S trimers, is predominantly modified in the Golgi by processed glycans. Three incompletely occupied sites of O-linked glycosylation were detected. Viruses pseudotyped with natural variants of the serine/threonine residues implicated in O-linked glycosylation were generally infectious and exhibited sensitivity to neutralization by soluble ACE2 and convalescent antisera comparable to that of the wild-type virus. Unlike other natural cysteine variants, a Cys15Phe (C15F) mutant retained partial, but unstable, infectivity. These findings enhance our understanding of the Golgi processing of the native SARS-CoV-2 S glycoprotein carbohydrates and could assist the design of interventions.
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Objective:To observe the expression levels of small ubiquitinated protein specific protease (SENP) 1 and small ubiquitin-related modifier protein (SUMO) 1 in patients with diffuse large B-cell lymphoma (DLBCL), and analyze the clinical value of evaluating prognosis.Methods:The clinical data of 66 patients with DLBCL (DLBCL group) in Inner Mongolia People′s Hospital from February 2017 to October 2020 were retrospectively analyzed, and 60 cases of healthy people in the same period were selected as the healthy control group. The expression levels of SENP1 and SUMO1 were detected by enzyme linked immunosorbent assay (ELISA). The correlation between the expression levels of SENP1, SUMO1 and clinical characteristics was analyzed. The independent risk factors affecting the prognosis were analyzed by Cox multivariate analysis.Results:The SENP1 in DLBCL group was significantly higher than that in healthy control group (50.39 ± 6.86 vs. 7.47 ± 1.32), the SUMO1 in DLBCL group was significantly lower than that in healthy control group (8.84 ± 2.13 vs. 31.49 ± 5.89), and there were statistical differences ( t = 47.640 and 29.210, P<0.01). There were statistical differences in SENP1 and SUMO1 among patients with different clinical stages ( P<0.01). The expression levels of SENP1 and SUMO1 were correlated with clinical stage and international prognostic index (IPI) ( P<0.05), and were not correlated with age, gender, disease site and clinical symptoms ( P>0.05). The 3-year survival rate in patients with high SENP1 expression (30 cases) was significantly lower than that in patients with low SENP1 expression (36 cases), the 3-year survival rate in patients with high SUMO1 expression (38 cases) was significantly higher than that in patients with low SUMO1 expression (28 cases), and there were statistical differences (26.67% vs. 75.00% and 73.68% vs. 39.29%, P<0.05). Cox multivariate regression analysis result showed that clinical stage, IPI, SENP1 and SUMO1 were independent risk factors affecting the prognosis in patients with DLBCL ( HR = 1.352, 1.487, 2.048 and 3.295; 95% CI 1.180 to 1.691, 1.187 to 1.602, 2.536 to 4.023 and 2.752 to 5.325; P<0.05 or <0.01). Conclusions:In patients with DLBCL, SENP1 is highly expressed and SUMO1 is lowly expressed. The expression levels of SENP1 and SUMO1 are closely related to clinical stage and IPI in patients with DLBCL, and they are independent risk factors of the prognosis.
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SARS-CoV-2, a betacoronavirus, is the cause of the COVID-19 pandemic. The SARS-CoV-2 spike (S) glycoprotein trimer mediates virus entry into host cells and cytopathic effects. We studied the contribution of several S glycoprotein features to these functions, focusing on those that differ among related coronaviruses. Acquisition of the furin cleavage site by the SARS-CoV-2 S glycoprotein decreased virus stability and infectivity, but greatly enhanced the ability to form lethal syncytia. Notably, the D614G change found in globally predominant SARS-CoV-2 strains restored infectivity, modestly enhanced responsiveness to the ACE2 receptor and susceptibility to neutralizing sera, and tightened association of the S1 subunit with the trimer. Apparently, two unique features of the SARS-CoV-2 S glycoprotein, the furin cleavage site and D614G, have evolved to balance virus infectivity, stability, cytopathicity and antibody vulnerability. Although the endodomain (cytoplasmic tail) of the S2 subunit was not absolutely required for virus entry or syncytium formation, alteration of palmitoylated cysteine residues in the cytoplasmic tail decreased the efficiency of these processes. As proteolytic cleavage contributes to the activation of the SARS-CoV-2 S glycoprotein, we evaluated the ability of protease inhibitors to suppress S glycoprotein function. Matrix metalloprotease inhibitors suppressed S-mediated cell-cell fusion, but not virus entry. Synergy between inhibitors of matrix metalloproteases and TMPRSS2 suggests that both proteases can activate the S glycoprotein during the process of syncytium formation. These results provide insights into SARS-CoV-2 S glycoprotein-host cell interactions that likely contribute to the transmission and pathogenicity of this pandemic agent. IMPORTANCEThe development of an effective and durable SARS-CoV-2 vaccine is essential for combating the growing COVID-19 pandemic. The SARS-CoV-2 spike (S) glycoprotein is the main target of neutralizing antibodies elicited during virus infection or following vaccination. Knowledge of the spike glycoprotein evolution, function and interactions with host factors will help researchers to develop effective vaccine immunogens and treatments. Here we identify key features of the spike glycoprotein, including the furin cleavage site and the D614G natural mutation, that modulate viral cytopathic effects, infectivity and sensitivity to inhibition. We also identify two inhibitors of host metalloproteases that block S-mediated cell-cell fusion, which contributes to the destruction of the virus-infected cell.
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Objective To investigate the clinical value of the combined detection of Golgi protein 73 (GP73),alpha-fetoprotein variant-L3 (AFP-L3)and transforming growth factorβ1(TGFβ1)in the early diagnosis of hepatocellular carcinoma (HCC).Meth-ods 48 cases of healthy control,42 cases of hepatitis B,50 cases of posthepatitic cirrhosis and 58 cases of HCC were selected and detected GP73,AFP-L3 and TGFβ1.The detection results were compared among 4 groups.Results (1)The levels of GP73,AFP-L3 and TGFβ1 had statistical differences among 4 groups(P <0.05 );(2 )The positive rate of the 3-marker combined detection reached 96.55%,which was higher than that of the 2-marker combined detection and the single marker detection.Conclusion (1) GP73,AFP-L3 and TGFβ1 may be used as the serum indicators for the early diagnosis of HCC;(2)Compared with the traditional HCC marker AFP,AFP-L3 has relatively high sensitivity and specificity and has the important role in the differential diagnosis of benign and malignant diseases of the liver,which is considered as a better serum marker in the HCC diagnosis;(3)The 3-indicator combined detection can significantly improve the positive detection rate of HCC and has better application value.
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Objective To study the roles of serum tumor necrosis factor-α (TNF-α),sTNFR-Ⅰ and sT-NFR-Ⅱ in asthmatic children.Methods The levels of serum TNF-α,sTNFR-Ⅰ and sTNFR-Ⅱ in 60 asthmatic children,including 30 cases of acute exacerbation group and 30 cases of clinical paracmasia group,and 22 cases of healthy children (control group) were detected by ELISA.Results (1) The level of serum TNF-α in acute exacerbation group was (98.87 ± 16.25) ng/L,it is significantly higher than the clinical paracmasia group (62.19 ± 15.85) ng/L and control group (44.25 ± 10.44) ng/L (F =94.78,P ＜ 0.05).The level of serum sTNFR-Ⅰ and sTNFR-Ⅱ in acute exacerbation group were (11.14 ±2.04) μg/L and (11.81 ±2.14) μg/L respectively,they were significantly higher than their own clinical remission group (8.91 ± 1.63) μg/L and (9.36 ± 1.72) μg/L,also significantly higher than the control group (5.03 ± 1.18) μg/L and (5.21 ±1.23) μg/L,(F =83.03 and 87.62,all P ＜ 0.05).The levels of TNF-α,sTNFR-Ⅰ and sTNFR-Ⅱ in clinical paracmasia group were significantly higher than that in control group (P ＜ 0.05).(2) The levels of sTNFR-Ⅰ and sTNFR-Ⅱ in asthmatic children,both acute exacerbation and clinical paracmasia,were positively correlated (r=0.908,P ＜ 0.05 and r =0.737,P ＜ 0.05).Conclusion The level of TNF-α maybe indicate the inflammatory severity of asthma,and the changes of serum sTNFR-Ⅰ and sTNFR-Ⅱ were closely related with asthmatic airway inflammation.
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ObjectiveTo analyze the serum creatinine level among apparently healthy primary and secondary school students in Inner Mongolia and explore the distribution of serum creatinine by ethnic,regional,gender and age,and establish the reference interval of serum creatinine in different gender and different age groups of primary and secondary school students.MethodsLargesample clinical epidemiological investigation was applied by two-stage clustering sampling method.Random sample of 2630 primary and secondary school students from 9 to 18-year-old was selected from four district in Inner Mongolia including Hohhot,Wulanchabu,Xilin Gol and Bayan Drow from July 2009 to June 2010.After screening outlier individual,the total of 2614 subjects were enrolled,involving 1288 male and 1326 female subjects,1584 Han and1030 Mongolian.The venous blood was collected and serum was separated.The serum creatinine concentration was measured as soon as possible.Furthermore, creatinine levels of different regions,ethnic,gender and age group were compared by analysis of variance or t-test and that of different group were compared by SNK method.Percentile was used to describe the distribution of serum Cr level of different age groups.The reference interval of serum Cr for primary and secondary school students were established by gender and age (P2.5 -P97.5 ).The curve was smoothed using age-specific percentile ( LMS )curve smoothing method.ResultsThe differences of Cr levels were statistically significant between different regions,ethnic,gender and age groups.The reference intervals of creatinine for 9 - 11,12,13 - 14,15,and 16 - 18 year-old males were 35 - 66,37 - 73,39 - 78,47 - 87 and 49 - 91 μmol/L,respectively.The intervals for 9 - 10,11 - 12,13 - 15,and 16 - 18 year-old females were 32 - 60,34 - 63,38 -73 and 40 -74 μmol/L,respectively.Conclusion The reference intervals of serum creatinine for health primary and secondary school students in the Inner Mongolia is established,which is useful for clinicians,especially pediatricians to judge and assess renal function for 9 to 18 year-old patients.( Chin J Lab Med,2012,35:805-809 )
