SARS-CoV-2 infection causes periodontal fibrotic pathogenesis through deregulating mitochondrial beta-oxidation.

The global high prevalence of COVID-19 is a major challenge for health professionals and patients. SARS-CoV-2 virus has four structural protein components: the spike protein, envelope protein, membrane protein, and nucleocapsid protein. The SARS-CoV-2 virus mutates predominantly in the spike proteins, whilst the other key viral components usually remain stable. Essentially the pathological functions of the SARS-CoV-2 virus on different cell types are still largely unknown. Previous studies have shown that the human oral cavity can potentially act as reservoir of the SARS-CoV-2 virus. However, the consequence of SARS-CoV-2 viral infection on human oral health has not been systematically examined. COVID-19 can cause severe oral mucosa lesions and is likely to be connected with poor periodontal conditions. Fibroblasts are the major cell type inside periodontal ligament (PDL) and express the SARS-CoV-2 receptor: Angiotensin-converting enzyme 2 (ACE2), whose expression level can increase upon bacterial infection hence potentially provide a direct route of SARS-CoV-2 infection to PDL fibroblasts. In this research, we aimed to study the pathogenicity of SARS-CoV-2 viral components on human fibroblasts. We found that by exposing to SARS-CoV-2, especially to the viral envelope and membrane proteins, the human periodontal fibroblasts could develop fibrotic pathogenic phenotypes, including hyperproliferation that was simultaneously induced with increased apoptosis and senescence. The fibrotic degeneration was mediated by a down-regulation of mitochondrial ß-oxidation in the fibroblasts. Fatty acid ß-oxidation inhibitor, etomoxir treatment could mirror the same pathological consequence on the cells, similar to SARS-CoV-2 infection. Our results therefore provide novel mechanistic insights into how SARS-CoV-2 infection can affect human periodontal health at the cell and molecular level with potential new therapeutic targets for COVID-19 induced fibrosis.

Coronaviral ORF6 protein mediates inter-organelle contacts and modulates host cell lipid flux for virus production.

Lipid droplets (LDs) form inter-organelle contacts with the endoplasmic reticulum (ER) that promote their biogenesis, while LD contacts with mitochondria enhance ß-oxidation of contained fatty acids. Viruses have been shown to take advantage of lipid droplets to promote viral production, but it remains unclear whether they also modulate the interactions between LDs and other organelles. Here, we showed that coronavirus ORF6 protein targets LDs and is localized to the mitochondria-LD and ER-LD contact sites, where it regulates LD biogenesis and lipolysis. At the molecular level, we find that ORF6 inserts into the LD lipid monolayer via its two amphipathic helices. ORF6 further interacts with ER membrane proteins BAP31 and USE1 to mediate ER-LDs contact formation. Additionally, ORF6 interacts with the SAM complex in the mitochondrial outer membrane to link mitochondria to LDs. In doing so, ORF6 promotes cellular lipolysis and LD biogenesis to reprogram host cell lipid flux and facilitate viral production.

Advances in developing ACE2 derivatives against SARS-CoV-2.

Extensive immune evasion of SARS-CoV-2 rendered therapeutic antibodies ineffective in the COVID-19 pandemic. Propagating SARS-CoV-2 variants are characterised by immune evasion capacity through key amino acid mutations, but can still bind human angiotensin-converting enzyme 2 (ACE2) through the spike protein and are, thus, sensitive to ACE2-mimicking decoys as inhibitors. In this Review, we examine advances in the development of ACE2 derivatives from the past 3 years, including the recombinant ACE2 proteins, ACE2-loaded extracellular vesicles, ACE2-mimicking antibodies, and peptide or mini-protein mimetics of ACE2. Several ACE2 derivatives are granted potent neutralisation efficacy against SARS-CoV-2 variants that rival or surpass endogenous antibodies by various auxiliary techniques such as chemical modification and practical recombinant design. The derivatives also represent enhanced production efficiency and improved bioavailability. In addition to these derivatives of ACE2, new effective therapeutics against SARS-CoV-2 variants are expected to be developed.

Advances in developing ACE2 derivatives against SARS-CoV-2

Extensive immune evasion of SARS-CoV-2 rendered therapeutic antibodies ineffective in the COVID-19 pandemic. Propagating SARS-CoV-2 variants are characterised by immune evasion capacity through key amino acid mutations, but can still bind human angiotensin-converting enzyme 2 (ACE2) through the spike protein and are, thus, sensitive to ACE2-mimicking decoys as inhibitors. In this Review, we examine advances in the development of ACE2 derivatives from the past 3 years, including the recombinant ACE2 proteins, ACE2-loaded extracellular vesicles, ACE2-mimicking antibodies, and peptide or mini-protein mimetics of ACE2. Several ACE2 derivatives are granted potent neutralisation efficacy against SARS-CoV-2 variants that rival or surpass endogenous antibodies by various auxiliary techniques such as chemical modification and practical recombinant design. The derivatives also represent enhanced production efficiency and improved bioavailability. In addition to these derivatives of ACE2, new effective therapeutics against SARS-CoV-2 variants are expected to be developed.

Coronavirus Subverts ER-phagy by Hijacking FAM134B and ATL3 into p62 Condensates to Facilitate Viral Replication

ER-phagy is a form of autophagy, which is mediated by ER-phagy receptors and selectively degrades endoplasmic reticulum (ER). RNA viruses have been shown to utilize the ER as a membrane source to establish their replication organelles double-membrane vesicles (DMVs). However, whether viruses modulate ER-phagy to drive viral DMV formation and its underlying molecular mechanisms remain largely unknown. Here, we demonstrate that coronavirus subverts ER-phagy by hijacking the ER-phagy receptors FAM134B and ATL3 into p62 condensates, resulting in increased viral replication. Mechanistically, we show that viral protein ORF8 binds to and undergoes condensation with p62. FAM134B and ATL3 interact with homodimer of ORF8 and are aggregated into ORF8/p62 liquid droplets, leading to ER-phagy inhibition. ORF8/p62 condensates disrupt ER-phagy to facilitate viral DMV formation and activates ER stress. Together, our data highlight how coronavirus modulates ER-phagy to drive viral replication by hijacking ER-phagy receptors. Graphical abstract Tan et al. describe an important mechanism by which SARS-CoV-2 protein ORF8 inhibits ER-phagy by hijacking the receptors FAM134B and ATL3 into p62 condensates, facilitating the production of viral replication organelle double membrane vesicles.

PF-D-Trimer, a protective SARS-CoV-2 subunit vaccine: immunogenicity and application.

The COVID-19 pandemic, caused by the SARS-CoV-2 virus, has had and continues to have a significant impact on global public health. One of the characteristics of SARS-CoV-2 is a surface homotrimeric spike protein, which is primarily responsible for the host immune response upon infection. Here we present the preclinical studies of a broadly protective SARS-CoV-2 subunit vaccine developed from our trimer domain platform using the Delta spike protein, from antigen design through purification, vaccine evaluation and manufacturability. The pre-fusion trimerized Delta spike protein, PF-D-Trimer, was highly expressed in Chinese hamster ovary (CHO) cells, purified by a rapid one-step anti-Trimer Domain monoclonal antibody immunoaffinity process and prepared as a vaccine formulation with an adjuvant. Immunogenicity studies have shown that this vaccine candidate induces robust immune responses in mouse, rat and Syrian hamster models. It also protects K18-hACE2 transgenic mice in a homologous viral challenge. Neutralizing antibodies induced by this vaccine show cross-reactivity against the ancestral WA1, Delta and several Omicrons, including BA.5.2. The formulated PF-D Trimer is stable for up to six months without refrigeration. The Trimer Domain platform was proven to be a key technology in the rapid production of PF-D-Trimer vaccine and may be crucial to accelerate the development and accessibility of updated versions of SARS-CoV-2 vaccines.

The burden of acute pancreatitis on COVID-19 in the United States.

Background: Although SARS-CoV-2 primarily affects the respiratory system, gastrointestinal symptoms were also seen. Our study analyzed the prevalence and impact of acute pancreatitis (AP) on COVID-19 hospitalizations in the United States. Methods: The 2020 National Inpatient Sample database was used to identify patients with COVID-19. The patients were stratified into 2 groups based on the presence of AP. AP as well as its impact on COVID-19 outcomes were evaluated. The primary outcome was in-hospital mortality. Secondary outcomes were intensive care unit (ICU) admissions, shock, acute kidney injury (AKI), sepsis, length of stay, and total hospitalization charges. Univariate and multivariate logistic/linear regression analyses were performed. Results: The study population comprised 1,581,585 patients with COVID-19, from which 0.61% of people had AP. Patients with COVID-19 and AP had a higher incidence of sepsis, shock, ICU admissions, and AKI. On multivariate analysis, patients with AP had higher mortality (adjusted odds ratio [aOR] 1.19, 95% confidence interval [CI] 1.03-1.38; P=0.02). We also noted a higher risk of sepsis (aOR 1.22, 95%CI 1.01-1.48; P=0.04), shock (aOR 2.09, 95%CI 1.83-2.40; P<0.001), AKI (aOR 1.79, 95%CI 1.61-1.99; P<0.001), and ICU admissions (aOR 1.56, 95%CI 1.38-1.77; P<0.001). Patients with AP also had a longer length of stay (+2.03 days, 95%CI 1.45-2.60; P<0.001), and higher hospitalization charges ($44,088.41, 95%CI $33,198.41-54,978.41; P<0.001). Conclusions: Our study revealed that the prevalence of AP in patients with COVID-19 was 0.61%. Although this was not strikingly high, the presence of AP is associated with worse outcomes and higher resource utilization.

Coronavirus subverts ER-phagy by hijacking FAM134B and ATL3 into p62 condensates to facilitate viral replication.

ER-phagy is a form of autophagy that is mediated by ER-phagy receptors and selectively degrades endoplasmic reticulum (ER). Coronaviruses have been shown to use the ER as a membrane source to establish their double-membrane vesicles (DMVs). However, whether viruses modulate ER-phagy to drive viral DMV formation and its underlying molecular mechanisms remains largely unknown. Here, we demonstrate that coronavirus subverts ER-phagy by hijacking the ER-phagy receptors FAM134B and ATL3 into p62 condensates, resulting in increased viral replication. Mechanistically, we show that viral protein ORF8 binds to and undergoes condensation with p62. FAM134B and ATL3 interact with homodimer of ORF8 and are aggregated into ORF8/p62 liquid droplets, leading to ER-phagy inhibition. ORF8/p62 condensates disrupt ER-phagy to facilitate viral DMV formation and activate ER stress. Together, our data highlight how coronavirus modulates ER-phagy to drive viral replication by hijacking ER-phagy receptors.

The E3 Ubiquitin Ligase RNF5 Facilitates SARS-CoV-2 Membrane Protein-Mediated Virion Release.

As an enveloped virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) contains a membrane protein (M) that mediates viral release from cellular membranes. However, the molecular mechanisms of SARS-CoV-2 virion release remain poorly understood. In the present study, we performed RNA interference (RNAi) screening and identified the E3 ligase RNF5, which mediates the ubiquitination of SARS-CoV-2 M at residue K15 to enhance the interaction of the viral envelope protein (E) with M, whereas the deubiquitinating enzyme POH1 negatively regulates this process. The M-E complex ensures the uniform size of viral particles for viral maturation and mediates virion release. Moreover, M traffics from the Golgi apparatus to autophagosomes and uses autophagosomes for virion release, and this process is dependent on RNF5-mediated ubiquitin modification and M-E interaction. These results demonstrate that ubiquitin modification of SARS-CoV-2 M stabilizes the M-E complex and uses autophagosomes for virion release. IMPORTANCE Enveloped virus particles are released from the membranes of host cells, and viral membrane proteins (M) are critical for this process. A better understanding of the molecular mechanisms of SARS-CoV-2 assembly and budding is critical for the development of antiviral therapies. Envelope protein (E) and M of SARS-CoV-2 form complexes to mediate viral assembly and budding. RNF5 was identified to play a role as the E3 ligase, and POH1 was demonstrated to function as the deubiquitinating enzyme of SARS-CoV-2 M. The two components collectively regulate the interaction of M with E to promote viral assembly and budding. Ubiquitinated M uses autophagosomes for viral release. Our findings provide insights into the mechanisms of SARS-CoV-2 assembly and budding, demonstrating the importance of ubiquitination modification and autophagy in viral replication.

An ACE2-Based Decoy Inhibitor Effectively Neutralizes SARS-CoV-2 Omicron BA.5 Variant.

The recently circulating SARS-CoV-2 Omicron BA.5 is rampaging the world with elevated transmissibility compared to the original SARS-CoV-2 strain. Immune escape of BA.5 was observed after treatment with many monoclonal antibodies, calling for broad-spectrum, immune-escape-evading therapeutics. In retrospect, we previously reported Kansetin as an ACE2 mimetic and a protein antagonist against SARS-CoV-2, which proved potent neutralization bioactivity on the Reference, Alpha, Beta, Delta, and Omicron strains of SARS-CoV-2. Since BA.5 is expected to rely on the interaction of the Spike complex with human ACE2 for cell entry, we reasonably assumed the lasting efficacy of the ACE2-mimicking Kansetin for neutralizing the new SARS-CoV-2 variant. The investigation was accordingly performed on in vitro Kansetin-Spike binding affinity by SPR and cell infection inhibition ability with pseudovirus and live virus assays. As a result, Kansetin showed dissociation constant KD and half inhibition concentration IC50 at the nanomolar to picomolar level, featuring a competent inhibition effect against the BA.5 sublineage. Conclusively, Kansetin is expected to be a promising therapeutic option against BA.5 and future SARS-CoV-2 sublineages.

Mechanisms of SARS-CoV-2 Infection-Induced Kidney Injury: A Literature Review.

The severe acute respiratory coronavirus 2 (SARS-CoV-2) has become a life-threatening pandemic. Clinical evidence suggests that kidney involvement is common and might lead to mild proteinuria and even advanced acute kidney injury (AKI). Moreover, AKI caused by coronavirus disease 2019 (COVID-19) has been reported in several countries and regions, resulting in high patient mortality. COVID-19-induced kidney injury is affected by several factors including direct kidney injury mediated by the combination of virus and angiotensin-converting enzyme 2, immune response dysregulation, cytokine storm driven by SARS-CoV-2 infection, organ interactions, hypercoagulable state, and endothelial dysfunction. In this review, we summarized the mechanism of AKI caused by SARS-CoV-2 infection through literature search and analysis.

Review and Thinking on Forensic Pathological Changes of Coronavirus-Infected Diseases.

Since the beginning of this century, three types of coronavirus have widely transmitted and caused severe diseases and deaths, which strongly indicates that severe infectious diseases caused by coronavirus infection are not accidental events. Coronavirus-infected diseases are mainly manifested by respiratory symptoms, with multiple organ dysfunctions. Precisely investigating the pathological process, characteristics and pathogenesis of coronavirus-infected diseases will be beneficial for us to understand clinical manifestations and provide targeted suggestions on prophylaxis and treatment. This paper briefly reviews the pathological findings of three known coronavirus-infected diseases, and attempts to construct the pathological spectrum of coronavirus-infected diseases, aiming to provide reference and thinking for autopsy, histopathological examination and animal infection model study of coronavirus-infected diseases.

Gender and Ethnic Disparities of Acute Kidney Injury in COVID-19 Infected Patients: A Literature Review.

Coronavirus disease 2019(COVID-19) has become a public health emergency of concern worldwide. COVID-19 is a new infectious disease arising from Coronavirus 2 (SARS-CoV-2). It has a strong transmission capacity and can cause severe and even fatal respiratory diseases. It can also affect other organs such as the heart, kidneys and digestive tract. Clinical evidence indicates that kidney injury is a common complication of COVID-19, and acute kidney injury (AKI) may even occur in severely ill patients. Data from China and the United States showed that male sex, Black race, the elderly, chronic kidney disease, diabetes, hypertension, cardiovascular disease, and higher body mass index are associated with COVID-19-induced AKI. In this review, we found gender and ethnic differences in the occurrence and development of AKI in patients with COVID-19 through literature search and analysis. By summarizing the mechanism of gender and ethnic differences in AKI among patients with COVID-19, we found that male and Black race have more progress to COVID-19-induced AKI than their counterparts.

Imparting reusable and SARS-CoV-2 inhibition properties to standard masks through metal-organic nanocoatings.

Face masks are effective response to address this havoc pandemic caused by respiratory infection virus, but they are lack of reusable, antibacterial, and antiviral abilities due to their simple filtration mechanism, bringing to a supply shortage and severe plastic pollution globally. Herein, we designed reusable, antiviral, and antibacterial masks (referred to as R2A masks) that transformed from commonly-used standard masks and household fabrics based on the polyphenol-based surface functionalization. R2A nanocoatings are mainly composed of supramolecular complexation of natural polyphenols and metal ions, possessing a high performance of antibacterial property and comprehensive recyclability. Interfacial interaction of R2A nanocoating can effectively capture the spreading of particulate matters and aerosols containing virus-mimic nanoparticles even after 10 recycles. Moreover, R2A masks exist antibacteria and antivirus for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Collectively, this simple functional enhancement of masks provides a sustainable and strategic preparation for combating the infectious respiratory diseases.

Drastic decline in sera neutralization against SARS-CoV-2 Omicron variant in Wuhan COVID-19 convalescents.

Global concern has been raised by the emergence and rapid transmission of the heavily mutated SARS-CoV-2 Omicron variant (B.1.1.529). So far, the infection features and immune escape ability of the Omicron variant have not been extensively studied. Here, we produced the Omicron pseudovirus and compared its entry, membrane fusion, and immune escape efficiency with the original strain and the dominating Delta variant. We found the Omicron variant showed slightly higher infectivity than the Delta variant and a similar ability to compete with the Delta variant in using Angiotensin-converting enzyme 2 (ACE2) in a BHK21-ACE2 cell line. However, the Omicron showed a significantly reduced fusogenicity than the original strain and the Delta variant in both BHK21-ACE2 and Vero-E6 cells. The neutralization assay testing the Wuhan convalescents' sera one-year post-infection showed a more dramatic reduction (10.15 fold) of neutralization against the Omicron variant than the Delta variant (1.79 fold) compared with the original strain with D614G. Notably, immune-boosting through three vaccine shots significantly improved the convalescents' immunity against the Omicron variants. Our results reveal a reduced fusogenicity and a striking immune escape ability of the Omicron variant, highlighting the importance of booster shots against the challenge of the SARS-CoV-2 antigenic drift.

Antibody neutralization to SARS-CoV-2 and variants after 1 year in Wuhan, China.

Most COVID-19 convalescents can build effective anti-SARS-CoV-2 humoral immunity, but it remains unclear how long it can maintain and how efficiently it can prevent the reinfection of the emerging SARS-CoV-2 variants. Here, we tested the sera from 248 COVID-19 convalescents around 1 year post-infection in Wuhan, the earliest known epicenter. SARS-CoV-2 immunoglobulin G (IgG) was well maintained in most patients and potently neutralizes the infection of the original strain and the B.1.1.7 variant. However, varying degrees of immune escape was observed on the other tested variants in a patient-specific manner, with individuals showing remarkably broad neutralization potency. The immune escape can be largely attributed to several critical spike mutations. These results suggest that SARS-CoV-2 can elicit long-lasting immunity but this is escaped by the emerging variants.

Detection of multiple lesions of gastrointestinal tract for endoscopy using artificial intelligence model: a pilot study.

BACKGROUND: This study was aimed to develop a computer-aided diagnosis (CAD) system with deep-learning technique and to validate its efficiency on detecting the four categories of lesions such as polyps, advanced cancer, erosion/ulcer and varices at endoscopy. METHODS: A deep convolutional neural network (CNN) that consists of more than 50 layers were trained with a big dataset containing 327,121 white light images (WLI) of endoscopy from 117,005 cases collected from 2012 to 2017. Two CAD models were developed using images with or without annotation of the training dataset. The efficiency of the CAD system detecting the four categories of lesions was validated by another dataset containing consecutive cases from 2018 to 2019. RESULTS: A total of 1734 cases with 33,959 images were included in the validation datasets which containing lesions of polyps 1265, advanced cancer 500, erosion/ulcer 486, and varices 248. The CAD system developed in this study may detect polyps, advanced cancer, erosion/ulcer and varices as abnormality with the sensitivity of 88.3% and specificity of 90.3%, respectively, in 0.05 s. The training datasets with annotation may enhance either sensitivity or specificity about 20%, p = 0.000. The sensitivities and specificities for polyps, advanced cancer, erosion/ulcer and varices reached about 90%, respectively. The detect efficiency for the four categories of lesions reached to 89.7%. CONCLUSION: The CAD model for detection of multiple lesions in gastrointestinal lumen would be potentially developed into a double check along with real-time assessment and interpretation of the findings encountered by the endoscopists and may be a benefit to reduce the events of missing lesions.

Tubular epithelial cell-to-macrophage communication forms a negative feedback loop via extracellular vesicle transfer to promote renal inflammation and apoptosis in diabetic nephropathy.

Background: Macrophage infiltration around lipotoxic tubular epithelial cells (TECs) is a hallmark of diabetic nephropathy (DN). However, how these two types of cells communicate remains obscure. We previously demonstrated that LRG1 was elevated in the process of kidney injury. Here, we demonstrated that macrophage-derived, LRG1-enriched extracellular vesicles (EVs) exacerbated DN. Methods: We induced an experimental T2DM mouse model with a HFD diet for four months. Renal primary epithelial cells and macrophage-derived EVs were isolated from T2D mice by differential ultracentrifugation. To investigate whether lipotoxic TEC-derived EV (EVe) activate macrophages, mouse bone marrow-derived macrophages (BMDMs) were incubated with EVe. To investigate whether activated macrophage-derived EVs (EVm) induce lipotoxic TEC apoptosis, EVm were cocultured with primary renal tubular epithelial cells. Subsequently, we evaluated the effect of LRG1 in EVe by investigating the apoptosis mechanism. Results: We demonstrated that incubation of primary TECs of DN or HK-2 mTECs with lysophosphatidyl choline (LPC) increased the release of EVe. Interestingly, TEC-derived EVe activated an inflammatory phenotype in macrophages and induced the release of macrophage-derived EVm. Furthermore, EVm could induce apoptosis in TECs injured by LPC. Importantly, we found that leucine-rich α-2-glycoprotein 1 (LRG1)-enriched EVe activated macrophages via a TGFßR1-dependent process and that tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-enriched EVm induced apoptosis in injured TECs via a death receptor 5 (DR5)-dependent process. Conclusion: Our findings indicated a novel cell communication mechanism between tubular epithelial cells and macrophages in DN, which could be a potential therapeutic target.