Objective To elucidate the correlation between specific nucleocapsid(N)protein mutant of the SARS-CoV-2 B.1.1.7 variant and clinical stratification in COVID-19 patients,revealing their impact on N protein liquid-liquid phase separation(LLPS)and host innate immune response.Methods Based on whole-genome sequencing data of the SARS-CoV-2 B.1.1.7 lineage from the GISAID database,non-synonymous mutation sites significantly associated with mild/severe clinical phenotypes were screened.For high-frequency N protein mutant,IFN-β promoter transcriptional activity was quantitatively measured using a dual-luciferase reporter system.qPCR was used to detect the mRNA expression levels of interferon(IFN)-β,interleukin(IL)-6 and tumor necrosis factor(TNF)-α.LLPS characteristics were observed by confocal microscopy.The ubiquitination status of host MAVS was detected by Western blot assay.Results A total of 17 640 non-synonymous mutation sites were identified,among which 65 were associated with mild cases and 20 were related to severe cases,with a mutation frequency>1%.The N protein mutation sites associated with severe cases were D3L,M234I and R203K-G204R-T205I.N protein and the mutants NM234I,NR203K-G204R-T205I inhibited the promoter activity of IFN-β(P＜0.05).Compared to the wild type N protein,NR203K-G204R-T205I mutation significantly reduced the mRNA levels of IFN-β,IL-6 and TNF-α(P＜0.05),and altered the phase separation state by dispersing the formation of LLPS condensates.However,N mutant did not affect the ubiquitination modification of host MAVS.Conclusion N protein mutants of the SARS-CoV-2 B.1.1.7 variant can influence the clinical prognosis of COVID-19 patients by altering LLPS status and suppressing the innate immune responses.These finding provides a theoretical basis for the design of antiviral drugs targeting the N protein.

Objective To elucidate the correlation between specific nucleocapsid(N)protein mutant of the SARS-CoV-2 B.1.1.7 variant and clinical stratification in COVID-19 patients,revealing their impact on N protein liquid-liquid phase separation(LLPS)and host innate immune response.Methods Based on whole-genome sequencing data of the SARS-CoV-2 B.1.1.7 lineage from the GISAID database,non-synonymous mutation sites significantly associated with mild/severe clinical phenotypes were screened.For high-frequency N protein mutant,IFN-β promoter transcriptional activity was quantitatively measured using a dual-luciferase reporter system.qPCR was used to detect the mRNA expression levels of interferon(IFN)-β,interleukin(IL)-6 and tumor necrosis factor(TNF)-α.LLPS characteristics were observed by confocal microscopy.The ubiquitination status of host MAVS was detected by Western blot assay.Results A total of 17 640 non-synonymous mutation sites were identified,among which 65 were associated with mild cases and 20 were related to severe cases,with a mutation frequency>1%.The N protein mutation sites associated with severe cases were D3L,M234I and R203K-G204R-T205I.N protein and the mutants NM234I,NR203K-G204R-T205I inhibited the promoter activity of IFN-β(P＜0.05).Compared to the wild type N protein,NR203K-G204R-T205I mutation significantly reduced the mRNA levels of IFN-β,IL-6 and TNF-α(P＜0.05),and altered the phase separation state by dispersing the formation of LLPS condensates.However,N mutant did not affect the ubiquitination modification of host MAVS.Conclusion N protein mutants of the SARS-CoV-2 B.1.1.7 variant can influence the clinical prognosis of COVID-19 patients by altering LLPS status and suppressing the innate immune responses.These finding provides a theoretical basis for the design of antiviral drugs targeting the N protein.

Objective To explore the influence of intensive glycemic control by insulin pump on prognosis of critically ill patients with lung infection and respiratory failure.Methods In the emergency intensive care unit (EICU),200 critically ill patients with hyperglycemia (A-PACHE II score >15 ,random blood glucose > 11.1 mmol /L)were collected and randomly di-vided into the intensive insulin therapy (IIT)group and the convention insulin therapy(CIT) group(use insulin pump to control blood glucose).IIT group and CIT group included 31 cases and 33 cases of pulmonary infection and respiratory failure.Ventilator and antibiotic use days,short-term mortality (within 28 days),rate of hypoglycemia,nosocomial infection,hospital stay and hospital costs were observed and compared between two groups.Results There was no significant differences between two groups in aspects of age,sex ratio,oxygen saturation,pressure of oxygen, pressure of Carbon dioxide,pH,blood pressure,respiratory failure type,blood glucose,elec-trolytes,inflammation,heart function,liver and kidney function,fasting C peptide,HbAlc and APACHE Ⅱ score(P >0.05).APACHE II score at the time of 3 days and 7 days after admission, nosocomial infection,short-term mortality hospital day and hospital costs (P <0.05)in the IIT group were significantly lower and shorter than the CIT group.The hypoglycemia incidence rate of the IIT group was significantly higher than that of the CIT group (P <0.01).Result of serious hypoglycemia showed no significant difference between the two groups .Conclusion Strict intensive glucose control on pulmonary infection and respiratory failure may bring more benefits for acute and critically ill patients,and it can reduce the short-term mortality rate.

Objective To explore the influence of intensive glycemic control by insulin pump on prognosis of critically ill patients with lung infection and respiratory failure.Methods In the emergency intensive care unit (EICU),200 critically ill patients with hyperglycemia (A-PACHE II score >15 ,random blood glucose > 11.1 mmol /L)were collected and randomly di-vided into the intensive insulin therapy (IIT)group and the convention insulin therapy(CIT) group(use insulin pump to control blood glucose).IIT group and CIT group included 31 cases and 33 cases of pulmonary infection and respiratory failure.Ventilator and antibiotic use days,short-term mortality (within 28 days),rate of hypoglycemia,nosocomial infection,hospital stay and hospital costs were observed and compared between two groups.Results There was no significant differences between two groups in aspects of age,sex ratio,oxygen saturation,pressure of oxygen, pressure of Carbon dioxide,pH,blood pressure,respiratory failure type,blood glucose,elec-trolytes,inflammation,heart function,liver and kidney function,fasting C peptide,HbAlc and APACHE Ⅱ score(P >0.05).APACHE II score at the time of 3 days and 7 days after admission, nosocomial infection,short-term mortality hospital day and hospital costs (P <0.05)in the IIT group were significantly lower and shorter than the CIT group.The hypoglycemia incidence rate of the IIT group was significantly higher than that of the CIT group (P <0.01).Result of serious hypoglycemia showed no significant difference between the two groups .Conclusion Strict intensive glucose control on pulmonary infection and respiratory failure may bring more benefits for acute and critically ill patients,and it can reduce the short-term mortality rate.