Targeting G9a translational mechanism of SARS-CoV-2 pathogenesis for multifaceted therapeutics of COVID-19 and its sequalae (preprint)

By largely unknown mechanism(s), SARS-CoV-2 hijacks the host translation apparatus to promote COVID-19 pathogenesis. We report that the histone methyltransferase G9a noncanonically regulates viral hijacking of the translation machinery to bring about COVID-19 symptoms of hyperinflammation, lymphopenia, and blood coagulation. Chemoproteomic analysis of COVID-19 patient peripheral mononuclear blood cells (PBMC) identified enhanced interactions between SARS-CoV-2-upregulated G9a and distinct translation regulators, particularly the N6-methyladenosine (m6A) RNA methylase METTL3. These interactions with translation regulators implicated G9a in translational regulation of COVID-19. Inhibition of G9a activity suppressed SARS-CoV-2 replication in human alveolar epithelial cells. Accordingly, multi-omics analysis of the same alveolar cells identified SARS-CoV-2-induced changes at the transcriptional, m6A-epitranscriptional, translational, and post-translational (phosphorylation or secretion) levels that were reversed by inhibitor treatment. As suggested by the aforesaid chemoproteomic analysis, these multi-omics-correlated changes revealed a G9a-regulated translational mechanism of COVID-19 pathogenesis in which G9a directs translation of viral and host proteins associated with SARS-CoV-2 replication and with dysregulation of host response. Comparison of proteomic analyses of G9a inhibitor-treated, SARS-CoV-2 infected cells, or ex vivo culture of patient PBMCs, with COVID-19 patient data revealed that G9a inhibition reversed the patient proteomic landscape that correlated with COVID-19 pathology/symptoms. These data also indicated that the G9a-regulated, inhibitor-reversed, translational mechanism outperformed G9a-transcriptional suppression to ultimately determine COVID-19 pathogenesis and to define the inhibitor action, from which biomarkers of serve symptom vulnerability were mechanistically derived. This cell line-to-patient conservation of G9a-translated, COVID-19 proteome suggests that G9a inhibitors can be used to treat patients with COVID-19, particularly patients with long-lasting COVID-19 sequelae.

Surveillance of SARS-CoV-2 in the environment and animal samples of the Huanan Seafood Market (preprint)

Emerging in December 2019, coronavirus disease 2019 (COVID-19) eventually became a pandemic and has posed a tremendous threat to global public health. However, the origins of SARS-CoV-2, the causative agent of COVID-19, remain to be determined. It has reported that a certain number of the early case clusters had a contact history with Huanan Seafood Market. Therefore, surveillance of SARS-CoV-2 within the market is of vital importance. Herein, we presented the SARS-CoV-2 detection results of 1380 samples collected from the environment and the animals within the market in early 2020. By SARS-CoV-2-specific RT-qPCR, 73 environmental samples tested positive for SARS-CoV-2 and three live viruses were successfully isolated. The viruses from the market shared nucleotide identity of 99.980% to 99.993% with the human isolate HCoV/Wuhan/IVDC-HB-01. In contrast, no virus was detected in the animal swabs covering 18 species of animals in the market. The SARS-COV-2 nucleic acids in the positive environmental samples showed significant correlation of abundance of Homo sapiens with SARS-CoV-2. In summary, this study provided convincing evidence of the prevalence of SARS-CoV-2 in the Huanan Seafood Market during the early stage of COVID-19 outbreak.

Functional Multi-Omics Reveals Noncanonical Function of G9a in Translational Regulation of Chronic Inflammation (preprint)

By largely unknown mechanisms, dysregulated gene-specific translation directly contributes to chronic inflammation-associated diseases such as sepsis and ARDS. Here, we report that G9a, a histone methyltransferase and well-regarded transcriptional repressor, non-canonically or non-epigenetically activates translation of select antimicrobial genes to promote proliferation of cytokine producing macrophages and to impair T cell function; all hallmarks of endotoxin-tolerance related complications including sepsis, ARDS and COVID19. Mechanistically, G9a interacts with translation regulators including METTL3, an N6-methyladenosine or m6A RNA methyltransferase, and methylates it to cooperatively upregulate the translation of certain m6A-modified mRNAs that encode immune checkpoint and anti-inflammatory proteins. Further, translatome proteomic analysis of ET macrophages progressively treated by a G9a inhibitor identified proteins showing G9a-dependent translation that unite the networks associated with hyperinflammation and T cell dysfunction. Overall, we identified a previously unrecognized function of G9a in gene-specific translation that can be leveraged to treat ET-related chronic inflammatory diseases.

Successful treatment of a kidney transplant patient with COVID-19 and late-onset Pneumocystis jirovecii pneumonia (preprint)

Background: Solid transplant patients are susceptible to Pneumocystis jirovecii pneumonia (PJP). While the vast majority of PJP cases occur within the first 6 months after transplantation, very few PJP cases are seen beyond 1 year post transplantation (late-onset PJP). PJP and coronavirus disease 2019 (COVID-19, caused by infection with SARS-CoV-2) share quite a few common clinical manifestations and imaging findings, making the diagnosis of PJP often underappreciated during the current COVID-19 pandemic. To date, only 1 case of kidney transplantation who developed COVID-19 and late-onset PJP has been reported, but this patient also suffered from many other infections and died from respiratory failure and multiple organ dysfunction syndrome. A successful treatment of kidney patients with COVID-19 and late-onset PJP has not been reported. Case presentation: We present a case of a 55-year-old male kidney transplant patient with COVID-19 who also developed late-onset PJP. He received a combined strategy, including specific anti-pneumocystis therapy, symptomatic supportive therapy, adjusted immunosuppressive therapy, and use of antiviral/antibiotics drugs, ending with a favorable outcome. Conclusions: This case highlights the importance of prompt and differential diagnosis of PJP in kidney transplant patients with SARS-CoV-2 infection. Further studies are required to clarify if kidney transplant patients with COVID-19 could be prone to develop late-onset PJP and how these patients should be treated.

Novel gene-specific translation mechanism of dysregulated, chronic inflammation reveals promising, multifaceted COVID-19 therapeutics (preprint)

Hyperinflammation and lymphopenia provoked by SARS-CoV-2-activated macrophages contribute to the high mortality of Coronavirus Disease 2019 (COVID-19) patients. Thus, defining host pathways aberrantly activated in patient macrophages is critical for developing effective therapeutics. We discovered that G9a, a histone methyltransferase that is overexpressed in COVID-19 patients with high viral load, activates translation of specific genes that induce hyperinflammation and impairment of T cell function or lymphopenia. This noncanonical, pro-translation activity of G9a contrasts with its canonical epigenetic function. In endotoxin-tolerant (ET) macrophages that mimic conditions which render patients with pre-existing chronic inflammatory diseases vulnerable to severe symptoms, our chemoproteomic approach with a biotinylated inhibitor of G9a identified multiple G9a-associated translation regulatory pathways that were upregulated by SARS-CoV-2 infection. Further, quantitative translatome analysis of ET macrophages treated progressively with the G9a inhibitor profiled G9a-translated proteins that unite the networks associated with viral replication and the SARS-CoV-2-induced host response in severe patients. Accordingly, inhibition of G9a-associated pathways produced multifaceted, systematic effects, namely, restoration of T cell function, mitigation of hyperinflammation, and suppression of viral replication. Importantly, as a host-directed mechanism, this G9a-targeted, combined therapeutics is refractory to emerging antiviral-resistant mutants of SARS-CoV-2, or any virus, that hijacks host responses.

Infection Prevention and Control Workflow of Nuclear Medicine Department during Novel Coronavirus Pneumonia Epidemic Period

Nuclear medical examination has its particularity. Most patients need to stay a long time in a relatively closed environment after injection of radioactive tracers. There is a risk of cross infection between medical staff and patients ,and between patients. For better epidemic prevention and control work, we need to take appropriate measures to ensure the safety of medical staff and patients. According to the diagnosis and treatment plan of NCP issued by National Health Commission and the guidelines of nuclear medicine, this article summarized the process and prevention and control work management strategy of nuclear medicine.

Optimization of the Working Procedure of Radionuclide Treatment Ward during 2019-nCoV Prevention

Since the end of 2019, Novel Coronavirus Pneumonia (2019-nCov) has appeared and spread rapidly in the world. During the epidemic period, how to control the infection in the working procedure of radionuclide treatment ward is a clinical protection problem that must be solved. If a novel coronavirus pneumonia (NCP) is suspected or diagnosed, the most important thing is to isolate the relevant doctors and patients on the spot in time and initiate relevant NCP clinical emergency plans and procedures. When the radioactive infected medical waste is disinfected, it should be treated as radioactive waste. Therefore, it is necessary to optimize the working procedures of radionuclide therapy ward.

Corticosteroid therapy for corona virus disease 2019-related acute respiratory distress syndrome: a cohort study with propensity score analysis (preprint)

Background: The impact of corticosteroid therapy on outcomes of patients with Coronavirus disease-2019 (COVID-19) is highly controversial. We aimed to compare the risk of death between COVID-19-related ARDS patients with corticosteroid treatment and those without. Methods In this single-centre retrospective observational study, patients with ARDS caused by COVID-19 between 24 December 2019 and 24 February 2020 were enrolled. The primary outcome was 60-day in-hospital death. The exposure was prescribed systemic corticosteroids or not. Time-dependent Cox regression models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for 60-day in-hospital mortality. Results A total of 382 patients including 226 (59.2%) patients who received systemic corticosteroids and 156 (40.8%) patients with standard treatment were analyzed. The maximum dose of corticosteroids was 80.0 (IQR 40.0–80.0) mg equivalent methylprednisolone per day, and duration of corticosteroid treatment was 7.0 (4.0–12.0) days in total. In Cox regression analysis using corticosteroid treatment as a time-varying variable, corticosteroid treatment was associated with a significant reduction in risk of in-hospital death within 60 days (HR, 0.48; 95% CI, 0.25, 0.93; p  = 0.0285). The association remained significantly after adjusting for age, sex, Sequential Organ Failure Assessment score at hospital admission, propensity score of corticosteroid treatment, and comorbidities (HR: 0.51; CI: 0.27, 0.99; p  = 0.0471). Corticosteroids were not associated with delayed viral RNA clearance in our cohort. Conclusion In this clinical practice setting, low-to-moderate dose corticosteroid treatment was associated with reduced risk of death in COVID-19 patients who developed ARDS.