Thromboinflammation is the major cause of morbidity and mortality in COVID‐19 patients, and post‐mortem examination demonstrates the presence of platelet‐rich thrombi and microangiopathy in visceral ...organs. Moreover, persistent microclots were detected in both acute COVID‐19 and long COVID plasma samples. However, the molecular mechanism of SARS‐CoV‐2‐induced thromboinflammation is still unclear. We found that the spleen tyrosine kinase (Syk)‐coupled C‐type lectin member 2 (CLEC2), which was highly expressed in platelets and alveolar macrophages, interacted with the receptor‐binding domain (RBD) of SARS‐CoV‐2 spike protein (SARS‐CoV‐2 RBD) directly. Unlike the thread‐like NETs, SARS‐CoV‐2‐induced aggregated NET formation in the presence of wild‐type (WT), but not CLEC2‐deficient platelets. Furthermore, SARS‐CoV‐2 spike pseudotyped lentivirus was able to induce NET formation via CLEC2, indicating SARS‐CoV‐2 RBD engaged CLEC2 to activate platelets to enhance NET formation. Administration of CLEC2.Fc inhibited SARS‐CoV‐2‐induced NET formation and thromboinflammation in AAV‐ACE2‐infected mice. Thus, CLEC2 is a novel pattern recognition receptor for SARS‐CoV‐2, and CLEC2.Fc and may become a promising therapeutic agent to inhibit SARS‐CoV‐2‐induced thromboinflammation and reduced the risk of post‐acute sequelae of COVID‐19 (PASC) in the future.
Synopsis
CLEC2 interacts with SARS‐CoV‐2 spike RBD and is critical for SARS‐CoV‐2‐induced lung injury. In the presence of platelets, SARS‐CoV‐2 induces robust NET formation and cytokine release, while administration of CLEC2.Fc prevents platelet‐mediated enhancement of NET formation and cytokine storm via blocking interactions between CLEC2 and SARS‐CoV‐2 spike protein.
CLEC2 interacts with SARS‐CoV‐2 Spike RBD of wild type, alpha, beta, gamma, delta, and omicron, but not with SARS‐CoV Spike RBD.
SARS‐CoV‐2 Spike RBD activates platelet via CLEC2 inducing aggregated NET formation.
SARS‐CoV‐2 upregulates the expression of podoplanin in the lungs after infection.
Recombinant CLEC2.Fc inhibits SARS‐CoV‐2‐induced thromboinflammation in the lungs and heart.
Recombinant CLEC2.Fc attenuates SARS‐CoV‐2‐induced NET formation and collagen deposition in the lungs.
CLEC2 interacts with SARS‐CoV‐2 spike RBD and is critical for SARS‐CoV‐2‐induced lung injury. In the presence of platelets, SARS‐CoV‐2 induces robust NET formation and cytokine release, while administration of CLEC2.Fc prevents platelet‐mediated enhancement of NET formation and cytokine storm via blocking interactions between CLEC2 and SARS‐CoV‐2 spike protein.
The novel coronavirus disease (COVID-19) pandemic remains a global public health crisis, presenting a broad range of challenges. To help address some of the main problems, the scientific community ...has designed vaccines, diagnostic tools and therapeutics for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The rapid pace of technology development, especially with regard to vaccines, represents a stunning and historic scientific achievement. Nevertheless, many challenges remain to be overcome, such as improving vaccine and drug treatment efficacies for emergent mutant strains of SARS-CoV-2. Outbreaks of more infectious variants continue to diminish the utility of available vaccines and drugs. Thus, the effectiveness of vaccines and drugs against the most current variants is a primary consideration in the continual analyses of clinical data that supports updated regulatory decisions. The first two vaccines granted Emergency Use Authorizations (EUAs), BNT162b2 and mRNA-1273, still show more than 60% protection efficacy against the most widespread current SARS-CoV-2 variant, Omicron. This variant carries more than 30 mutations in the spike protein, which has largely abrogated the neutralizing effects of therapeutic antibodies. Fortunately, some neutralizing antibodies and antiviral COVID-19 drugs treatments have shown continued clinical benefits. In this review, we provide a framework for understanding the ongoing development efforts for different types of vaccines and therapeutics, including small molecule and antibody drugs. The ripple effects of newly emergent variants, including updates to vaccines and drug repurposing efforts, are summarized. In addition, we summarize the clinical trials supporting the development and distribution of vaccines, small molecule drugs, and therapeutic antibodies with broad-spectrum activity against SARS-CoV-2 strains.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Abstract
Background
Coronavirus-induced disease 19 (COVID-19) infects more than three hundred and sixty million patients worldwide, and people with severe symptoms frequently die of acute respiratory ...distress syndrome (ARDS). Recent studies indicated that excessive neutrophil extracellular traps (NETs) contributed to immunothrombosis, thereby leading to extensive intravascular coagulopathy and multiple organ dysfunction. Thus, understanding the mechanism of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-induced NET formation would be helpful to reduce thrombosis and prevent ARDS in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.
Methods
We incubated SARS-CoV-2 with neutrophils in the presence or absence of platelets to observe NET formation. We further isolated extracellular vesicles from COVID-19 patients' sera (COVID-19-EVs) to examine their ability to induce NET formation.
Results
We demonstrated that antagonistic mAbs against anti-CLEC5A mAb and anti-TLR2 mAb can inhibit COVID-19-EVs-induced NET formation, and generated
clec5a
−/−
/tlr2
−/−
mice to confirm the critical roles of CLEC5A and TLR2 in SARS-CoV-2-induced lung inflammation in vivo. We found that virus-free extracellular COVID-19 EVs induced robust NET formation via Syk-coupled C-type lectin member 5A (CLEC5A) and TLR2. Blockade of CLEC5A inhibited COVID-19 EVs-induced NETosis, and simultaneous blockade of CLEC5A and TLR2 further suppressed SARS-CoV-2-induced NETosis in vitro. Moreover, thromboinflammation was attenuated dramatically in
clec5a
−/−
/tlr2
−/−
mice.
Conclusions
This study demonstrates that SARS-CoV-2-activated platelets produce EVs to enhance thromboinflammation via CLEC5A and TLR2, and highlight the importance of CLEC5A and TLR2 as therapeutic targets to reduce the risk of ARDS in COVID-19 patients.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The COVID-19 pandemic presents an unprecedented challenge to global public health. Rapid development and deployment of safe and effective vaccines are imperative to control the pandemic. In the ...current study, we applied our adjuvanted stable prefusion SARS-CoV-2 spike (S-2P)-based vaccine, MVC-COV1901, to hamster models to demonstrate immunogenicity and protection from virus challenge. Golden Syrian hamsters immunized intramuscularly with two injections of 1 µg or 5 µg of S-2P adjuvanted with CpG 1018 and aluminum hydroxide (alum) were challenged intranasally with SARS-CoV-2. Prior to virus challenge, the vaccine induced high levels of neutralizing antibodies with 10,000-fold higher IgG level and an average of 50-fold higher pseudovirus neutralizing titers in either dose groups than vehicle or adjuvant control groups. Six days after infection, vaccinated hamsters did not display any weight loss associated with infection and had significantly reduced lung pathology and most importantly, lung viral load levels were reduced to lower than detection limit compared to unvaccinated animals. Vaccination with either 1 μg or 5 μg of adjuvanted S-2P produced comparable immunogenicity and protection from infection. This study builds upon our previous results to support the clinical development of MVC-COV1901 as a safe, highly immunogenic, and protective COVID-19 vaccine.
Background and Aims
PreS mutants of HBV have been reported to be associated with HCC. We conducted a longitudinal study of the role of HBV preS mutations in the development of HCC, particularly in ...patients with chronic hepatitis B (CHB) having low HBV DNA or alanine aminotransferase (ALT) levels, and investigated the effects of secretion‐defective preS2 deletion mutant (preS2ΔMT) on hepatocyte damage in vitro and liver fibrosis in vivo.
Approach and Results
Association of preS mutations with HCC in 343 patients with CHB was evaluated by a retrospective case–control follow‐up study. Effects of preS2ΔMT on HBsAg retention, endoplasmic reticulum (ER) stress, calcium accumulation, mitochondrial dysfunction, and liver fibrosis were examined. Multivariate analysis revealed a significant association of preS mutations with HCC (HR, 3.210; 95% CI, 1.072‐9.613; P = 0.037) including cases with low HBV DNA or ALT levels (HR, 2.790; 95% CI, 1.133‐6.873; P = 0.026). Antiviral therapy reduced HCC risk, including cases with preS mutations. PreS2ΔMT expression promoted HBsAg retention in the ER and unfolded protein response (UPR). Transmission electron microscopic examination, MitoTracker staining, real‐time ATP assay, and calcium staining of preS2ΔMT‐expressing cells revealed aberrant ER and mitochondrial ultrastructure, reduction of mitochondrial membrane potential and ATP production, and calcium overload. Serum HBV secretion levels were ~100‐fold lower in preS2ΔMT‐infected humanized Fah–/–/ Rag2–/–/Il2rg–/– triple knockout mice than in wild‐type HBV‐infected mice. PreS2ΔMT‐infected mice displayed up‐regulation of UPR and caspase‐3 and enhanced liver fibrosis.
Conclusions
PreS mutations were significantly associated with HCC development in patients with CHB, including those with low HBV DNA or ALT levels. Antiviral therapy reduced HCC occurrence in patients with CHB, including those with preS mutations. Intracellular accumulation of mutated HBsAg induced or promoted ER stress, calcium overload, mitochondrial dysfunction, impaired energy metabolism, liver fibrosis, and HCC.
Background and Aims
Hepatitis B immunoglobulin (HBIG) has been routinely applied in the liver transplantation setting to block HBV reinfection of grafts. However, new monoclonal anti‐HBV surface ...antibodies have been developed to replace HBIG. The epitopes of such monoclonal antibodies may affect the emergence of escape variants and deserve study.
Approach and Results
The conformational epitope of sLenvervimab, a surrogate form of Lenvervimab, which is a monoclonal anti‐HBsAg antibody currently under phase 3 trial, was investigated by selecting escape mutants from a human liver chimeric mouse. HBV‐infected chimeric mice treated with sLenvervimab monotherapy showed an initial decline in circulating HBsAg levels, followed by a quick rebound in 1 month. Sequencing of circulating or liver HBV DNA revealed emerging variants, with replacement of amino acid E164 or T140, two residues widely separated in HBsAg. E164 HBV variants strongly resisted sLenvervimab neutralization in cell culture infection, and the T140 variant moderately resisted sLenvervimab neutralization. Natural HBV variants with amino‐acid replacements adjacent to E164 were constructed and examined for sLenvervimab neutralization effects. Variants with K160 replacement also resisted neutralization. These data revealed the conformational epitope of sLenvervimab.
Conclusions
Selection of antibody‐escape HBV variants in human chimeric mice works efficiently. Analysis of such emerging variants helps to identify anchor amino‐acid residues of the conformational epitope that are difficult to discover by conventional approaches.
COVID-19 in humans is caused by Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) that belongs to the beta family of coronaviruses. SARS-CoV-2 causes severe respiratory illness in 10-15% ...of infected individuals and mortality in 2-3%. Vaccines are urgently needed to prevent infection and to contain viral spread. Although several mRNA- and adenovirus-based vaccines are highly effective, their dependence on the "cold chain" transportation makes global vaccination a difficult task. In this context, a stable lyophilized vaccine may present certain advantages. Accordingly, establishing additional vaccine platforms remains vital to tackle SARS-CoV-2 and any future variants that may arise. Vaccinia virus (VACV) has been used to eradicate smallpox disease, and several attenuated viral strains with enhanced safety for human applications have been developed. We have generated two candidate SARS-CoV-2 vaccines based on two vaccinia viral strains, MVA and v-NY, that express full-length SARS-CoV-2 spike protein. Whereas MVA is growth-restricted in mammalian cells, the v-NY strain is replication-competent. We demonstrate that both candidate recombinant vaccines induce high titers of neutralizing antibodies in C57BL/6 mice vaccinated according to prime-boost regimens. Furthermore, our vaccination regimens generated TH1-biased immune responses in mice. Most importantly, prime-boost vaccination of a Syrian hamster infection model with MVA-S and v-NY-S protected the hamsters against SARS-CoV-2 infection, supporting that these two vaccines are promising candidates for future development. Finally, our vaccination regimens generated neutralizing antibodies that partially cross-neutralized SARS-CoV-2 variants of concern.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In the wake of shaping the energy future through materials innovation, lithium–sulfur batteries (LSBs) are top-of-the-line energy storage system attributed to their high theoretical energy density ...and specific capacity inclusive of low material costs. Despite their strengths, LSBs suffer from the cross-over of soluble polysulfide redox species to the anode, entailing fast capacity fading and inferior cycling stability. Adding to the concern, the insulating character of polysulfides lends to sluggish reaction kinetics. To address these challenges, we construct optimized polysulfide blockers-cum-conversion catalysts by accommodating the battery separator with covalent organic framework@Graphene (COF@G) composites. We settle on a crystalline TAPP-ETTB COF in the interest of its nitrogen-enriched scaffold with a regular pore geometry, providing ample lithiophilic sites for strong chemisorption and catalytic effect to polysulfides. On another front, graphene enables high electron mobility, boosting the sulfur redox kinetics. Consequently, a lithium–sulfur battery with a TAPP-ETTB COF@G-based separator demonstrates a high reversible capacity of 1489.8 mA h g–1 at 0.2 A g–1 after the first cycle and good cyclic performance (920 mA h g–1 after 400 cycles) together with excellent rate performance (827.7 mA h g–1 at 2 A g–1). The scope and opportunities to harness the designability and synthetic structural control in crystalline organic materials is a promising domain at the interface of sustainable materials, energy storage, and Li–S chemistry.
Anxiety disorders significantly impair quality of life. However, limited knowledge of the underlying mechanisms impedes the development of effective therapeutics. Previous studies have suggested that ...the expression of the Nptx2 gene is associated with anxiety, but the neurobiological processes underlying this association remain unclear. We generated multiple mouse models with knockout or overexpression of Nptx2 in specific brain regions and during different developmental stages to assess anxiety, adult neurogenesis, and glucocorticoid-related gene expression. Our results provide evidence that Nptx2 expression in the adult hippocampus regulates anxiety in mice. Eliminating Nptx2 expression in either the developing mouse brain or in adulthood leads to increased anxiety levels. The increase in anxiety was evident in hippocampus-specific Nptx2 knockout mice, but not in an amygdala specific knockouts. Gene expression analysis revealed increased expression of glucocorticoid receptor target genes in Nptx2 knockout mice after acute stress. Overexpression of Nptx2 in the hippocampus alleviates stress-induced anxious behaviors and reverses the changes in expression of glucocorticoid receptor related genes. In conclusion, we demonstrate that Nptx2 in the hippocampus performs a critical role in modulating anxiety, hippocampal cell proliferation, and glucocorticoid receptor related gene expression. Our results suggest Nptx2 may be a potential target for anxiolytic therapeutics.
Disulfidptosis a new cell death mode, which can cause the death of Hepatocellular Carcinoma (HCC) cells. However, the significance of disulfidptosis-related Long non-coding RNAs (DRLs) in the ...prognosis and immunotherapy of HCC remains unclear. Based on The Cancer Genome Atlas (TCGA) database, we used Least Absolute Shrinkage and Selection Operator (LASSO) and Cox regression model to construct DRL Prognostic Signature (DRLPS)-based risk scores and performed Gene Expression Omnibus outside validation. Survival analysis was performed and a nomogram was constructed. Moreover, we performed functional enrichment annotation, immune infiltration and drug sensitivity analyses. Five DRLs (AL590705.3, AC072054.1, AC069307.1, AC107959.3 and ZNF232-AS1) were identified to construct prognostic signature. DRLPS-based risk scores exhibited better predictive efficacy of survival than conventional clinical features. The nomogram showed high congruence between the predicted survival and observed survival. Gene set were mainly enriched in cell proliferation, differentiation and growth function related pathways. Immune cell infiltration in the low-risk group was significantly higher than that in the high-risk group. Additionally, the high-risk group exhibited higher sensitivity to Afatinib, Fulvestrant, Gefitinib, Osimertinib, Sapitinib, and Taselisib. In conclusion, our study highlighted the potential utility of the constructed DRLPS in the prognosis prediction of HCC patients, which demonstrated promising clinical application value.
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