Signal Transduction and Targeted Therapy

Neutralizing monoclonal antibodies (NAbs) with prophylactic and therapeutic efficacy have demonstrated fundamental importance in the control of SARS-CoV-2 transmission. However, their wide application has been largely limited by high cost and inconvenience in administration. Here, we developed an intranasal spray containing two synergetic human NAbs that could broadly neutralize the emerging Omicron variants in vitro. A unique synergetic neutralizing mechanism was identified that the two NAbs bound to exclusive epitopes on the RBD and structurally compensate each other in blocking the Spike-ACE2 interaction. Importantly, when given at low dosages for three consecutive days through the intranasal mucosal route, this cocktail showed significant improvement in the emergency preventive and therapeutic effects in hamsters challenged with authentic Omicron BA.1. Further, we performed an investigator-initiated trail in healthy volunteers (ChiCTR2200066525) to study the safety and pharmacokinetics of the antibody cocktail administrated as nasal spray. The nasal spray is generally safe and well tolerated without treatment related severe abnormal effects. The antibody cocktail nasal spray demonstrated nasal concentrations higher than the IC90 of neutralization activity against Omicron BA.4/5 even at 24 hours post dosing. Furthermore, nasal samples from the study subjects demonstrated potent neutralization activity against Omicron BA.4/5 in an ex vivo pseudovirus neutralization assay. Together, we provide a novel approach for NAb regimens, a potentially highly effective product with broad applicable perspective in depressing the infection risk of new epidemic variant and ameliorating the heavy medical burden of hospital. One Sentence SummaryAn intranasal spray of two synergetic antibodies cocktail neutralizing Omicron BA.4/5 and an initial clinical evaluation in healthy volunteers.

The comparison between traditional Chinese medicine Jinzhen Oral Liquid (JZOL) and western medicine in treating children with acute bronchitis (AB) showed encouraging outcomes. This trial evaluated the efficacy and safety of the JZOL for improving cough and expectoration in children with AB. 480 children were randomly assigned to take JZOL or Ambroxol Hydrochloride and Clenbuterol Hydrochloride Oral Solution for 7 days. The primary outcome was time-to-cough resolution. The median time-to-cough resolution in both groups was 5.0 days and the antitussive onset median time was only 1 day. This head to head randomized controlled trial showed that JZOL was not inferior to cough suppressant and phlegm resolving western medicine in treating cough and sputum and could comprehensively treat respiratory and systemic discomfort symptoms. Combined with clinical trials, the mechanism of JZOL against AB was uncovered by network target analysis, it was found that the pathways in TRP channels like IL-1{beta}/IL1R/TRPV1/TRPA1, NGF/TrkA/TRPV1/TRPA1 and PGE2/EP/PKA/TRPV1/TRPA1 might play important roles. Animal experiments further confirmed that inflammation and immune regulatory effect of JZOL in the treatment of AB were of vital importance and TRP channels was the key mechanism of action.

The recently emerged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of the ongoing global pandemic of COVID-19, may trigger immunosuppression in the early stage and a cytokine storm in the late stage of infection, however, the underlying mechanisms are not well understood. Here we demonstrated that the SARS-CoV-2 nucleocapsid (N) protein dually regulated innate immune responses, i.e., the low-dose N protein suppressed type I interferon (IFN-I) signaling and inflammatory cytokines, whereas high-dose N protein promoted IFN-I signaling and inflammatory cytokines. Mechanistically, the SARS-CoV-2 N protein interacted with the tripartite motif protein 25 (TRIM25), thereby dually regulating the phosphorylation and nuclear translocation of IRF3, STAT1 and STAT2. Additionally, low-dose N protein combined with TRIM25 could suppress retinoic acid-inducible gene I (RIG-I) ubiquitination and activation. Our findings revealed a regulatory mechanism of innate immune responses by the SARS-CoV-2 N protein, which would contribute to understanding the pathogenesis of SARS-CoV-2 and other SARS-like coronaviruses, and development of more effective strategies for controlling COVID-19.

The full activation of NLRP3 inflammasome needs two sequential signals: the fist priming signal and the second assembly signal. Various stimuli including infections and stress signals can provide the assembly signal. However, how NLRP3 detects diverse stimuli and becomes fully activated remain largely unknown. In this study, we found the second signal specially triggers the acetylation of NLRP3, which facilitates the aggregation of NLRP3 and its interaction with ASC and NEK7, thus promoting the assembly of inflammasome. Meanwhile, by employing pharmacological and molecular approaches, we identified KAT5 as a regulator of NLRP3 acetylation and activation. Furthermore, KAT5 specific inhibitor-NU9056 exhibited a robust suppressive effect on NLRP3 inflammasome both in vitro and in vivo. Thus, our study reveals a new mechanism for NLRP3 full activation and suggests targeting NLRP3 acetylation may provide a new approach for treatment of NLRP3 associated diseases.

Long-COVID-19 manifests as a multisystemic condition with varied symptoms lingering beyond three weeks of acute SARS-CoV-2 infection, though its underlying mechanisms remain elusive. Aiming to decipher the long-term molecular impacts of COVID-19, we conducted a transcriptomic analysis on PBMCs from 1-year post-covid patients, including individuals without pneumonia (NP, n=10), those with severe pneumonia (SP, n=11), and healthy controls (C, n=13). Our extensive RNA sequencing revealed 4843 differentially expressed genes (DEGs) and 1056 differentially expressed long non-coding RNAs (DElncRNAs) in "C vs NP," 1651 DEGs and 577 DElncRNAs in "C vs SP," 954 DEGs and 148 DElncRNAs in "NP vs SP," with 291 DEGs and 70 DElncRNAs shared across all groups. We identified 14 hub genes from 291 DEGs, with functional enrichment analysis showing upregulated DEGs mainly linked to inflammation and osteoclast differentiation, and downregulated DEGs to viral infections and immune responses. These hub genes play central roles in inflammatory and immune processes and are significantly associated with pneumonitis and diverse lung diseases. Investigations revealed unique immune cell signatures across DEG categories, associating upregulated DEGs with neutrophils and monocytes, and downregulated DEGs with CD4 memory effector T cells. Analysis of 14 hub genes showed notable upregulation in the no pneumonia group versus healthy controls, displaying complex patterns in the severe pneumonia group. Our study uncovered potential idiopathic pulmonary fibrosis signals in Long-COVID-19 patients PBMC transcriptome, highlighting the urgency for thorough monitoring and extended research to understand COVID-19s lasting effects. This study sheds light on COVID-19s transcriptomic changes and potential lasting effects, guiding future research and therapeutic approaches for Long-COVID-19.

The major concern of COVID-19 therapeutic monoclonal antibodies is the loss of efficacy to continuously emerging SARS-CoV-2 variants. To predict the antibodies efficacy to the future Omicron subvariants, we conducted deep mutational scanning (DMS) encompassing all single mutations in the receptor binding domain of BA.2 strain. In case of bebtelovimab that preserves neutralization activity against BA.2 and BA.5, broad range of amino acid substitutions at K444, V445 and G446 and some substitutions at P499 and T500 were indicated to achieve the antibody escape. Among currently increasing subvariants, BA2.75 carrying G446S partly and XBB with V445P and BQ.1 with K444T completely evade the neutralization of bebtelovimab, consistent with the DMS results. DMS can comprehensively characterize the antibody escape for efficient and effective management of future variants.

At the end of 2019, the SARS-CoV-2 induces an ongoing outbreak of pneumonia in China1, even more spread than SARS-CoV infection2. The entry of SARS-CoV into host cells mainly depends on the cell receptor (ACE2) recognition and spike protein cleavage-induced cell membrane fusion3,4. The spike protein of SARS-CoV-2 also binds to ACE2 with a similar affinity, whereas its spike protein cleavage remains unclear5,6. Here we show that an insertion sequence in the spike protein of SARS-CoV-2 enhances the cleavage efficiency, and besides pulmonary alveoli, intestinal and esophagus epithelium were also the target tissues of SARS-CoV-2. Compared with SARS-CoV, we found a SPRR insertion in the S1/S2 protease cleavage sites of SARS-CoV-2 spike protein increasing the cleavage efficiency by the protein sequence aligment and furin score calculation. Additionally, the insertion sequence facilitates the formation of an extended loop which was more suitable for protease recognition by the homology modeling and molicular docking. Furthermore, the single-cell transcriptomes identified that ACE2 and TMPRSSs are highly coexpressed in AT2 cells of lung, along with esophageal upper epithelial cells and absorptive enterocytes. Our results provide the bioinformatics evidence for the increased spike protein cleavage of SARS-CoV-2 and indicate its potential target cells.

Although 15-20% of COVID-19 patients experience hyper-inflammation induced by massive cytokine production, cellular triggers of this process and strategies to target them remain poorly understood. Here, we show that the N-terminal domain (NTD) of the spike protein from the SARS-CoV-2 and emerging variants B1.1.7 and B.1.351 substantially induces multiple inflammatory molecules in human monocytes and PBMCs. Further, we identified several protein kinases, including JAK1, EPHA7, IRAK1, MAPK12, and MAP3K8, as essential downstream mediators of NTD-induced cytokine release. Additionally, we found that the FDA-approved, multi-kinase inhibitor Ponatinib is a potent inhibitor of the NTD-mediated cytokine storm. Taken together, we propose that agents targeting multiple kinases required for the SARS-CoV-2-mediated cytokine storm, such as Ponatinib, may represent an attractive therapeutic option for treating moderate to severe COVID-19.

SARS-CoV-2 and its induced COVID-19 remains as a global health calamity. Severe symptoms and high mortality, caused by cytokine storm and acute respiratory distress syndrome in the lower respiratory airway, are always associated with elderly individuals and those with comorbidities; whereas mild or moderate COVID-19 patients have limited upper respiratory flu-like symptoms. There is an urgent need to investigate SARS-CoV-2 and other coronaviruses replication and immune responses in human respiratory systems. The human reconstituted airway epithelial air-liquid interface (ALI) models are the most physiologically relevant model for the investigation of coronavirus infection and virus-triggered innate immune signatures. We established ALI models representing both the upper and the lower respiratory airway to characterize the coronavirus infection kinetics, tissue pathophysiology, and innate immune signatures from upper and lower respiratory tract perspective. Our data suggested these in vitro ALI models maintain high physiological relevance with human airway tissues. The coronavirus induced immune response observed in these upper and lower respiratory airway models are similar to what has been reported in COVID-19 patients. The antiviral efficacy results of a few promising anti-coronavirus drugs in these models were consistent with previous reports and could be valuable for the human dose prediction. Taken together, our study demonstrates the importance of 3D airway epithelial ALI model for the understanding of coronavirus pathogenesis and the discovery and development of anti-coronavirus drugs.

The Omicron variant continuously evolves under the humoral immune pressure obtained by vaccination and SARS-CoV-2 infection and the resultant Omicron subvariants exhibit further immune evasion and antibody escape. Engineered ACE2 decoy composed of high-affinity ACE2 and IgG1 Fc domain is an alternative modality to neutralize SARS-CoV-2 and we previously reported its broad spectrum and therapeutic potential in rodent models. Here, we show that engineered ACE2 decoy retains the neutralization activity against Omicron subvariants including the currently emerging XBB and BQ.1 which completely evade antibodies in clinical use. The culture of SARS-CoV-2 under suboptimal concentration of neutralizing drugs generated SARS-CoV-2 mutants escaping wild-type ACE2 decoy and monoclonal antibodies, whereas no escape mutant emerged against engineered ACE2 decoy. As the efficient drug delivery to respiratory tract infection of SARS-CoV-2, inhalation of aerosolized decoy treated mice infected with SARS-CoV-2 at a 20-fold lower dose than the intravenous administration. Finally, engineered ACE2 decoy exhibited the therapeutic efficacy for COVID-19 in cynomolgus macaques. Collectively, these results indicate that engineered ACE2 decoy is the promising therapeutic strategy to overcome immune-evading SARS-CoV-2 variants and that liquid aerosol inhalation can be considered as a non-invasive approach to enhance efficacy in the treatment of COVID-19.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused a global pandemic due to its high transmissibility and ability to evade innate immune responses. Comprehensive characterization of the disease is essential for elucidating its pathophysiology and clinical progression. In this study, we performed multi-omics analyses of plasma samples collected from SARS-CoV-2-positive patients prior to clinical deterioration of coronavirus disease 2019 (COVID-19). These samples revealed the potential of previously reported clinical parameters, including CRP and neutrophil level, to predict COVID-19 exacerbation in the early stage. Our analysis identified a novel panel of molecules that precede the clinical manifestations associated with COVID-19 progression. These candidate biomarkers exhibited strong correlations with previously reported clinical and immunological parameters. Notably, several inflammation-related markers showed inverse associations with specific interferon subtypes, including IFN-6 and IFN-8, potentially reflecting mechanisms of SARS-CoV-2-mediated immune evasion. Our findings contribute to the understanding of virus-induced acute exacerbation and offer a valuable foundation for future pandemic research.

Emerging evidence indicates an intricate relationship between the SARS-CoV-2 infection and Multi-Organ Dysfunctions (MODs). Here, we have investigated the role of the Secretome of the SARS-CoV-2 infected pancreas and mechanistically linked it with the multi-organ dysfunction using the scRNA-seq analysis. We found that acinar-specific PRSS2, REG3A, REG1A, SPINK1, and ductal-specific SPP1, MMP7 genes are upregulated in alpha, beta, delta, and mesenchyme cells. Using extensive documented experimental evidence, we validated the association of upregulated pancreatic Secretome with coagulation cascade, complement activation, renin angiotensinogen system dysregulation, endothelial cell injury and thrombosis, immune system dysregulation, and fibrosis. Our finding suggests the influence of upregulated Secretome on multi-organ systems such as Nervous, Cardiovascular, Immune, Digestive, and Urogenital systems. In addition, we report that the secretory proteins IL1B, AGT, ALB, SPP1, CRP, SERPINA1, C3, TFRC, TNFSF10, and MIF are associated with diverse diseases. Thus, suggest the role of the pancreatic Secretome in SARS-CoV-2 associated MODs.

Systemic inflammation in critically ill patients can lead to serious consequences such as acute respiratory distress syndrome (ARDS), a condition characterized by the presence of lung inflammation, edema, and impaired gas exchange, associated with poor survival. Understanding molecular pathobiology is essential to improve critical care of these patients. To this end, we use multimodal profiles of SARS-CoV-2 infected hospitalized participants to the Biobanque Quebecoise de la COVID-19 (BQC-19) to characterize endophenotypes associated with different degrees of disease severity. Proteomic, metabolomic, and genomic characterization supported a role for neutrophil-associated procoagulant activity in severe COVID-19 ARDS that is inversely correlated with sphinghosine-1 phosphate plasma levels. Fibroblast Growth Factor Receptor (FGFR) and SH2-containing transforming protein 4 (SHC4) signaling were identified as molecular features associated with endophenotype 6 (EP6). Mechanical ventilation in EP6 was associated with alterations in lipoprotein metabolism. These findings help define the molecular mechanisms related to specific severe outcomes, that can be used to identify early unfavorable clinical trajectories and treatable traits to improve the survival of critically ill patients.

The SARS-CoV-2 pandemic poses an unprecedented public health crisis. Accumulating evidences suggest that SARS-CoV-2 infection causes dysregulation of immune system. However, the unique signature of early immune responses remains elusive. We characterized the transcriptome of rhesus macaques and mice infected with SARS-CoV-2. Alarmin S100A8 was robustly induced by SARS-CoV-2 in animal models as well as in COVID-19 patients. Paquinimod, a specific inhibitor of S100A8/A9, could reduce inflammatory response and rescue the pneumonia with substantial reduction of viral titers in SASR-CoV-2 infected animals. Remarkably, Paquinimod treatment resulted in 100% survival of mice in a lethal model of mouse coronavirus (MHV) infection. A novel group of neutrophils that contributed to the uncontrolled inflammation and onset of COVID-19 were dramatically induced by coronavirus infections. Paquinimod treatment could reduce these neutrophils and regain antiviral responses, unveiling key roles of S100A8/A9 and noncanonical neutrophils in the pathogenesis of COVID-19, highlighting new opportunities for therapeutic intervention.

2019 Novel Coronavirus (2019-nCoV) is a virus identified as the cause of the outbreak of pneumonia first detected in Wuhan, China. Investigations on the transmissibility, severity, and other features associated with this virus are ongoing. Currently, there is no vaccine or therapeutic antibody to prevent the infection, and more time is required to develop an effective immune strategy against the pathogen. In contrast, specific inhibitors targeting the key protease involved in replication and proliferation of the virus are the most effective means to alleviate the epidemic. The main protease of SARS-CoV is essential for the life cycle of the virus, which showed 96.1% of similarity with the main proteaseof 2019-nCoV, is considered to be an attractive target for drug development. In this study, we have identified 4 small molecular drugs with high binding capacity with SARS-CoV main protease by high-throughput screening based on the 8,000 clinical drug libraries, all these drugs have been widely used in clinical applications with guaranteed safety, which may serve as promising candidates to treat the infection of 2019-nCoV.

Several studies have identified the presence of functionally depleted CD8+ T cells in COVID-19 patients, and particularly abnormally reduced CD8+ T cells in severe/critical patients, which may be a major cause of disease progression and poor prognosis. In this study, a proliferating-depleted CD8+ T cell phenotype was observed in severe/critical COVID-19 patients through scRNA-seq and scTCR-seq analysis. These CD8+ T cells were subsequently found to be characterized by cell cycle arrest and downregulation of mitochondrial biogenesis and respiratory chain complex genes. Cellchat analysis revealed that the Galectin signaling pathways between infected lung epithelial cells and CD8+ T cells play the key role in inducing CD8+ T cell reduction and dysfunction in severe/critical COVID-19. We used SARS-COV-2 ORF3a to transfect A549 epithelial cells, and co-cultured with CD8+ T cells. The ex vivo experiments confirmed that galectin-3 inhibited the transcription of mitochondrial respiratory chain complex III/IV genes in CD8+ T cells by suppressing the nuclear translocation of nuclear respiratory factor 1 (NRF1). In addition, the regulatory effect of galectin-3 was correlated with the activation of ERK signaling and/or the inhibition of Akt signaling. Galectin-3 inhibitor, TD-139, promoted nuclear translocation of NRF1, and enhanced mitochondrial respiratory chain complex III/IV gene expression and mitochondrial biogenesis, then restore the expansion ability of CD8+ T cells. Our study improved the understanding the immunopathogenesis and provided new target for the prevention and treatment of severe/critical COVID-19.

Gastric cancer (GC) is one of the most malignant cancers, and cisplatin (Cis)-based chemotherapy remains the main clinical treatment for GC. However, Cis resistance often occurs, largely limiting its therapeutic efficacy in tumors. Therefore, a better understanding of the drug resistance mechanism could reveal new approaches for improving GC treatment efficacy. Here, we define the integrative role of nucleolar and coiled-body phosphoprotein 1 (NOLC1), a molecular chaperone that is significantly upregulated in GC tissues and Cis-resistant GC cells. Knocking down NOLC1 increased GC sensitivity to Cis by regulating ferroptosis. Mechanistically, NOLC1 binds to the p53 DNA binding domain (DBD), decreasing p53 nuclear accumulation stimulated by Cis and suppressing p53 transcriptional functions. Then, the p53-mediated ferroptosis is suppressed. Furthermore, the silence of NOLC1 promoted ferroptosis-induced immunogenic cell death (ICD) and reprogrammed the immunosuppressive tumor microenvironment, thereby increasing sensitivity to anti-programmed cell death-1 (PD-1) therapy plus Cis. The combination of anti-PD-1 plus Cis effectively inhibited GC growth without significant side effects. In summary, our findings reveal that targeting NOLC1 may be a novel therapeutic strategy for GC and may increase the efficacy of chemotherapy combined with immune checkpoint inhibitor (ICI) therapy.

The coronavirus disease 2019 (COVID-19) pandemic is caused by infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is spread primary via respiratory droplets and infects the lungs. Currently widely used cell lines and animals are unable to accurately mimic human physiological conditions because of the abnormal status of cell lines (transformed or cancer cells) and species differences between animals and humans. Organoids are stem cell-derived self-organized three-dimensional culture in vitro and model the physiological conditions of natural organs. Here we demonstrated that SARS-CoV-2 infected and extensively replicated in human embryonic stem cells (hESCs)-derived lung organoids, including airway and alveolar organoids. Ciliated cells, alveolar type 2 (AT2) cells and rare club cells were virus target cells. Electron microscopy captured typical replication, assembly and release ultrastructures and revealed the presence of viruses within lamellar bodies in AT2 cells. Virus infection induced more severe cell death in alveolar organoids than in airway organoids. Additionally, RNA-seq revealed early cell response to SARS-CoV-2 infection and an unexpected downregulation of ACE2 mRNA. Further, compared to the transmembrane protease, serine 2 (TMPRSS2) inhibitor camostat, the nucleotide analog prodrug Remdesivir potently inhibited SARS-CoV-2 replication in lung organoids. Therefore, human lung organoids can serve as a pathophysiological model for SARS-CoV-2 infection and drug discovery.

The spike (S) protein receptor-binding domain (RBD) of SARS-CoV-2 is an attractive target for COVID-19 vaccine developments, which naturally exists in a trimeric form. Here, guided by structural and computational analyses, we present a mutation-integrated trimeric form of RBD (mutI tri-RBD) as a broadly protective vaccine candidate, in which three RBDs were individually grafted from three different circulating SARS-CoV-2 strains including the prototype, Beta (B.1.351) and Kappa (B.1.617). The three RBDs were then connected end-to-end and co-assembled to possibly mimic the native trimeric arrangements in the natural S protein trimer. The recombinant expression of the mutI tri-RBD, as well as the homo-tri-RBD where the three RBDs were all truncated from the prototype strain, by mammalian cell exhibited correct folding, strong bio-activities, and high stability. The immunization of both the mutI tri-RBD and homo-tri-RBD plus aluminum adjuvant induced high levels of specific IgG and neutralizing antibodies against the SARS-CoV-2 prototype strain in mice. Notably, regarding to the "immune-escape" Beta (B.1.351) variant, mutI tri-RBD elicited significantly higher neutralizing antibody titers than homo-tri-RBD. Furthermore, due to harboring the immune-resistant mutations as well as the evolutionarily convergent hotspots, the designed mutI tri-RBD also induced strong broadly neutralizing activities against various SARS-CoV-2 variants, especially the variants partially resistant to homo-tri-RBD. Homo-tri-RBD has been approved by the China National Medical Products Administration to enter clinical trial (No. NCT04869592), and the superior broad neutralization performances against SARS-CoV-2 support the mutI tri-RBD as a more promising vaccine candidate for further clinical developments.

There is an urgent need for new antivirals with powerful therapeutic potential and tolerable side effects. In the present study, we found that recombinant human interferon-alpha (IFNa) triggers intrinsic and extrinsic cellular antiviral responses, as well as reduces replication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in vitro. Although IFNa alone was insufficient to completely abolish SARS-CoV-2 replication, combinations of IFNa with remdesivir or other antiviral agents (EIDD-2801, camostat, cycloheximide, or convalescent serum) showed strong synergy and effectively inhibited SARS-CoV-2 infection in human lung epithelial Calu-3 cells. Furthermore, we showed that the IFNa-remdesivir combination suppressed virus replication in human lung organoids, and that its single prophylactic dose attenuated SARS-CoV-2 infection in lungs of Syrian hamsters. Transcriptome and metabolomic analyses showed that the combination of IFNa-remdesivir suppressed virus-mediated changes in infected cells, although it affected the homeostasis of uninfected cells. We also demonstrated synergistic antiviral activity of IFNa2a-based combinations against other virus infections in vitro. Altogether, our results indicate that IFNa2a-based combination therapies can achieve higher efficacy while requiring lower dosage compared to monotherapies, making them attractive targets for further pre-clinical and clinical development.