SUMOylation of SARS-CoV-2 Nucleocapsid protein enhances its interaction affinity and plays a critical role for its nuclear translocation (preprint)

Viruses, such as SARS-CoV-2, infect hosts and take advantages of host cellular machinery for their genome replication and new virion production. Identification and elucidation of host pathways for viral infection are critical for understanding the viral life cycle and novel therapeutics development. SARS-CoV-2 N protein is critical for viral RNA(vRNA) genome packaging in new virion formation, Here, we report that identification of SUMOylation sites of SARS-CoV-2 N protein and role of SUMO modification in N protein interaction affinity with itself using our qFRET/MS coupled method. We found, for the first time, that the SUMO modification of N protein can significantly increase its interaction affinity with itself and may support its oligomer formation. One of the identified Lys residues, K65 was critical for N protein translocation to nucleus, where the vRNA replication and packaging take place. The in vitro assessment of the affinity of N protein to N protein with SUMO mutants provides insight of the oligomerized N protein formation after SUMO modification. These results suggest that the host human SUMOylation pathway may be very critical for N protein functions in viral replication. The host SUMOylation pathway may be a critical host factor for the SARS-CoV-2 virus life cycle. Identification and inhibition of critical host SUMOylation could provide a novel strategy for future anti-viral therapeutics development, such as SARS-CoV-2 and other viruses.

Engineered interferon alpha effectively improves clinical outcomes of COVID-19 patients (preprint)

Interferons are key to the antiviral host defense, yet the therapeutic value of interferon for coronavirus disease 2019 (COVID-19) is unknown. Recombinant super-compound interferon (rSIFN-co) is a new genetically engineered interferon, thus we conducted a multicenter, randomized controlled trial (ChiCTR2000029638) to evaluate the efficacy and safety of recombinant super-compound interferon versus traditional interferon alpha added to baseline antiviral agents (lopinavir–ritonavir or umifenovir) for the treatment of moderate-to-severe COVID-19. Participants received rSIFN-co (12 million international units [IU], twice daily) or interferon alpha (5 million IU, twice daily) nebulization added to baseline antiviral agents for no more than 28 days. The primary outcome was the time to clinical improvement. Secondary outcomes included the overall rate of clinical improvement assessed on day 28，the time to radiological improvement and virus nucleic acid negative conversion, and adverse events. 94 patients hospitalized with moderate-to-severe COVID-19 were included in the safety set (46 patients assigned to rSIFN-co group, 48 to interferon alpha group). Individuals in the rSIFN-co group showed shorter time to clinical improvement (11.5 days vs 14.0 days; P = 0.019) as compared to those in the interferon alpha group. The overall rate of clinical improvement on day 28 was much higher in the rSIFN-co group than that in the interferon alpha group (93.5% vs 77.1%; difference, 16.4%; 95% confidence interval 3% to 30%). The time to radiological improvement and the time to virus nucleic acid negative conversion were also much shorter in the rSIFN-co group (8.0 days vs 10.0 days, P = 0.002; 7.0 days vs 10.0 days, P = 0.018, respectively). Adverse events were reported in 13 (28.3%) patients in the rSIFN-co group and 18 (37.5%) patients in the interferon alpha group. No patients died during the study. Our study showed that rSIFN-co added to antiviral agents was safe and more efficient than interferon alpha plus antiviral agents in the treatment of moderate-to-severe COVID-19. Future clinical study of rSIFN-co therapy alone or combined with other antiviral therapy is warranted.

COVID-19 Recurrent Varies with Different Combinatorial Medical Treatments Determined by Machine Learning Approaches (preprint)

Various medical treatments for COVID-19 are attempted. After patients are discharged, SARS-CoV-2 recurring cases are reported and the recurrence could profoundly impact patient healthcare and social economics. To date, no data on the effects of medical treatments on recurrence has been published. We analyzed the treatment data of combinations of ten different drugs for the recurring cases in a single medical center, Shenzhen, China. A total of 417 patients were considered and 414 of them were included in this study (3 deaths) with mild-to-critical COVID-19. Patients were treated by 10 different drug combinations and followed up for recurrence for 28 days quarantine after being discharged from the medical center between February and May, 2020. We applied the Synthetic Minority Oversampling Technique (SMOTE) to overcome the rare recurring events in certain age groups and performed Virtual Twins (VT) analysis facilitated by random forest regression for medical treatment-recurrence classification. Among those drug combinations, Methylprednisolone/Interferon/Lopinavir/Ritonavir/Arbidol led to the lowest recurring rate (0.133) as compared to the average recurring rate (0.203). For the younger group (age 20-27) or the older group (age 60-70), the optimal drug combinations are different, but the above combination is still the second best. For obese patients, the combination of Ribavirin/Interferon/Lopinavir/Ritonavir/Arbidol led to the lowest recurring rate for age group of 20-50, whereas the combination of Interferon/Lopinavir/Ritonavir/Arbidol led to lowest recurring rate for age group of 50-70. The insights into combinatorial therapy we provided here shed lights on the use of a combination of (biological and chemical) anti-virus therapy and/or anti-cytokine storm as a potentially effective therapeutic treatment for COVID-19.

Recurrence of SARS-CoV-2 PCR positivity in COVID-19 patients: a single center experience and potential implications (preprint)

IMPORTANCE How to appropriately care for patients who become PCR-negative for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is still not known. Patients who have recovered from coronavirus disease 2019 (COVID-19) could profoundly impact the health care system if a subset were to be PCR-positive again with reactivated SARS-CoV-2. OBJECTIVE To characterize a single center COVID-19 cohort with and without recurrence of PCR positivity, and develop an algorithm to identify patients at high risk of retest positivity after discharge to inform health care policy and case management decision-making. DESIGN, SETTING, AND PARTICIPANTS A cohort of 414 patients with confirmed SARS-CoV-2 infection, at The Second Affiliated Hospital of Southern University of Science and Technology in Shenzhen, China from January 11 to April 23, 2020. EXPOSURES Polymerase chain reaction (PCR) and IgM-IgG antibody confirmed SARS-CoV-2 infection. MAIN OUTCOMES AND MEASURES Univariable and multivariable statistical analysis of the clinical, laboratory, radiologic image, medical treatment, and clinical course of admission/quarantine/readmission data to develop an algorithm to predict patients at risk of recurrence of PCR positivity. RESULTS 16.7% (95CI: 13.0%-20.3%) patients retest PCR positive 1 to 3 times after discharge, despite being in strict quarantine. The driving factors in the recurrence prediction model included: age, BMI; lowest levels of the blood laboratory tests during hospitalization for cholinesterase, fibrinogen, albumin, prealbumin, calcium, eGFR, creatinine; highest levels of the blood laboratory tests during hospitalization for total bilirubin, lactate dehydrogenase, alkaline phosphatase; the first test results during hospitalization for partial pressure of oxygen, white blood cell and lymphocyte counts, blood procalcitonin; and the first test episodic Ct value and the lowest Ct value of the nasopharyngeal swab RT PCR results. Area under the ROC curve is 0.786. CONCLUSIONS AND RELEVANCE This case series provides clinical characteristics of COVID-19 patients with recurrent PCR positivity, despite strict quarantine, at a 16.7% rate. Use of a recurrence prediction algorithm may identify patients at high risk of PCR retest positivity of SARS-CoV-2 and help modify COVID-19 case management and health policy approaches.