Hyphal Als proteins act as CR3 ligands to promote immune responses against Candida albicans.

Patients with decreased levels of CD18 (ß2 integrins) suffer from life-threatening bacterial and fungal infections. CD11b, the α subunit of integrin CR3 (CD11b/CD18, αMß2), is essential for mice to fight against systemic Candida albicans infections. Live elongating C. albicans activates CR3 in immune cells. However, the hyphal ligands that activate CR3 are not well defined. Here, we discovered that the C. albicans Als family proteins are recognized by the I domain of CD11b in macrophages. This recognition synergizes with the ß-glucan-bound lectin-like domain to activate CR3, thereby promoting Syk signaling and inflammasome activation. Dectin-2 activation serves as the "outside-in signaling" for CR3 activation at the entry site of incompletely sealed phagosomes, where a thick cuff of F-actin forms to strengthen the local interaction. In vitro, CD18 partially contributes to IL-1ß release from dendritic cells induced by purified hyphal Als3. In vivo, Als3 is vital for C. albicans clearance in mouse kidneys. These findings uncover a novel family of ligands for the CR3 I domain that promotes fungal clearance.

Mechanisms of the TGF-ß1/Smad3-signaling pathway in gender differences in alcoholic liver fibrosis.

The TGF-ß1/Smad3-signaling pathway and gender differences were investigated in alcoholic liver fibrosis. Mice were divided into female normal, female model, male normal, and male model groups. Liver injury and fibrosis were assessed using histopathology and serology. Western blotting was performed to analyze the expression of relevant factors. HSC-T6 cells were divided into estradiol + saline, estradiol + ethanol, testosterone + saline, and testosterone + ethanol groups, and similar assessments were conducted in vitro. Compared with the female model group, the male model group exhibited significantly increased GPT, GOT, TNF-α, IL-6, and testosterone levels, fibrosis rate, and TGF-ß1, Smad3, and PCNA expression, and significantly decreased estradiol levels and Caspase-3 expression. The apoptosis rate was higher in the estradiol + ethanol group than in the testosterone + ethanol group, although the testosterone + ethanol group exhibited significantly increased TNF-α, IL-6, Collagen-I, α-SMA, TGF-ß1, Smad3, and PCNA expression, and significantly decreased Caspase-3 expression. Alcoholic liver fibrosis showed significant gender differences associated with the TGF-ß1/Smad3-signaling pathway.

[Design and innovation of a utility model patent for tracheal cannula fixation belt].

Tracheostomy is a very common airway procedure in the treatment of critically ill neurological patients. At present, the traditional tracheal cannula fixation belt is easy to be contaminated, difficult to disinfect, and needs to be replaced regularly. It is prone to infection, skin injury, unplanned extubation and other adverse events, which cannot meet the clinical treatment effect and patient safety management. In order to overcome the above problems, the medical staff of the neurology intensive care unit of Henan Provincial People's Hospital designed a new type of tracheal cannula fixation belt to increase patient comfort and reduce complications, and obtained a National Utility Model Patent of China (ZL 2022 2 0855188.8). The main structure of the device includes a following shaped bending plate, a fastening belt, a locking pin, and a distance adjustment hole. The left and right sides of the shaped bending plate are equipped with fastening belts with breathable and anti-wear pads. The inner side of the left fastening belt is equipped with two sets of locking pins, and the outer surface of the right fastening belt and breathable and anti-wear pad is equipped with multiple sets of distance adjustment holes. Additionally, the back of the shaped bending plate is equipped with breathable buffer pads. The fastening belt can drive the following bending plate to stick tightly to the patient's neck. The operator installs the locking pin card into the distance adjustment hole according to the "one back" principle, and the fastening belts on both sides fix the device with the cooperation of the locking pin, greatly reducing the probability of excessive displacement of the tracheal tube during use, effectively improving the fixation effect of the device, strengthening the adaptability of the device to different personnel, and thus enhancing the practicality of the device. The new type of tracheal cannula fixation band is convenient, safe and efficient, which can increase patient comfort, reduce complications. It has certain clinical value and is suitable for clinical promotion.

Human transferrin receptor can mediate SARS-CoV-2 infection.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been detected in almost all organs of coronavirus disease-19 patients, although some organs do not express angiotensin-converting enzyme-2 (ACE2), a known receptor of SARS-CoV-2, implying the presence of alternative receptors and/or co-receptors. Here, we show that the ubiquitously distributed human transferrin receptor (TfR), which binds to diferric transferrin to traffic between membrane and endosome for the iron delivery cycle, can ACE2-independently mediate SARS-CoV-2 infection. Human, not mouse TfR, interacts with Spike protein with a high affinity (KD ~2.95 nM) to mediate SARS-CoV-2 endocytosis. TfR knock-down (TfR-deficiency is lethal) and overexpression inhibit and promote SARS-CoV-2 infection, respectively. Humanized TfR expression enables SARS-CoV-2 infection in baby hamster kidney cells and C57 mice, which are known to be insusceptible to the virus infection. Soluble TfR, Tf, designed peptides blocking TfR-Spike interaction and anti-TfR antibody show significant anti-COVID-19 effects in cell and monkey models. Collectively, this report indicates that TfR is a receptor/co-receptor of SARS-CoV-2 mediating SARS-CoV-2 entry and infectivity by likely using the TfR trafficking pathway.

Molecular cloning, tissue expression pattern, responses to different fatty acids and potential functions of lysophosphatidylcholine acyltransferase 1 (LPCAT1) in large yellow croaker (Larimichthys crocea).

In farmed fish, diets rich in palm oil have been observed to promote abnormal lipid build-up in the liver, subsequently leading to physiological harm and disease onset. Emerging research suggests that integrating phospholipids into the feed could serve as a potent countermeasure against hepatic impairments induced by vegetable oil consumption. Phosphatidylcholine is the most abundant type among phospholipids. In the metabolic processes of mammal, lysophosphatidylcholine acyltransferase 1 (LPCAT1), crucial for phosphatidylcholine remodeling, demonstrates a marked affinity towards palmitic acid (PA). Nonetheless, aspects concerning the cloning, tissue-specific distribution, and affinity of the LPCAT1 gene to diverse oil sources have yet to be elucidated in the large yellow croaker (Larimichthys crocea). Within the scope of this study, we successfully isolated and cloned the cDNA of the LPCAT1 gene from the large yellow croaker. Subsequent analysis revealed distinct gene expression patterns of LPCAT1 across ten different tissues of the species. The fully sequenced coding DNA sequence (CDS) of LPCAT1 spans 1503 bp and encodes a sequence of 500 amino acids. Comparative sequence alignment indicates that LPCAT1 shares a 69.75 % amino acid similarity with its counterparts in other species. Although LPCAT1 manifests across various tissues of the large yellow croaker, its predominance is markedly evident in the liver and gills. Furthermore, post exposure of the large yellow croaker's hepatocytes to varied fatty acids, PA has a strong response to LPCAT1. Upon the addition of appropriate lysolecithin to palm oil feed, the mRNA expression of LPCAT1 in the liver cells of the large yellow croaker showed significant variations compared to other subtypes. Concurrently, the mRNA expression of pro-inflammatory genes il-1ß, il-6, il-8, tnf-α and ifn-γ in the liver tissue of the large yellow croaker decreased. Interestingly, they exhibit the same trend of change. In conclusion, we have cloned the LPCAT1 gene on fish successfully and find the augmented gene response of LPCAT1 in hepatocytes under PA treatment first. The results of this study suggest that LPCAT1 may be associated with liver inflammation in fish and offer new insights into mitigating liver diseases in fish caused by palm oil feed.

Associations Between Plasma Orexin-A Level and Constipation in Cognitive Impairment.

BACKGROUND: Constipation is a common symptom in dementia, and the cause is controversial. Rare clinical studies focused on plasma orexin-A levels and constipation in dementia. OBJECTIVE: To evaluate the associations between orexin-A and constipation in patients with cognitive impairment. METHODS: A total of 21 patients with mild cognitive impairment (MCI), 142 with Alzheimer's disease (AD), and 57 with Lewy body dementia (LBD) were conducted. Besides informant-based history, neurological examinations or neuropsychological assessments, plasma levels of orexin-A, and constipation were assessed. The associations between orexin-A and constipation were evaluated by logistic regression models. RESULTS: There were 47/220 (21.36%) cognitive impairment patients having constipation, and the proportion of constipation in LBD (61.40%) was significantly higher than AD (5.63%) and MCI (19.05%). No significant age or sex differences in the prevalence of constipation were found in the MCI, AD, and LBD groups. We found the cognitive impairment patients with constipation had lower levels of plasma orexin-A [1.00 (0.86, 1.28) versus 1.29 (1.01, 1.50) ng/ml, p < 0.001] than those without. And the plasma levels of orexin-A were significantly associated with the occurrence of constipation after adjusting for all variables in all patients with cognitive impairment (OR = 0.151, 95% CI: 0.042-0.537, p = 0.003). And the same finding was more prominent in the LBD group (p = 0.048). CONCLUSIONS: The decrease of plasma level of orexin-A is closely associated with the occurrence of constipation. Orexin-A has an intestinal protective effect and is involved in the gastrointestinal symptoms of patients with cognitive impairment.

Construction of a molecular regulatory network related to fat deposition by multi-tissue transcriptome sequencing of Jiaxian red cattle.

Intramuscular fat (IMF) refers to the fat that accumulates between muscle bundles or within muscle cells, whose content significantly impacts the taste, tenderness, and flavor of meat products, making it a crucial economic characteristic in livestock production. However, the intricate mechanisms governing IMF deposition, involving non-coding RNAs (ncRNAs), genes, and complex regulatory networks, remain largely enigmatic. Identifying adipose tissue-specific genes and ncRNAs is paramount to unravel these molecular mysteries. This study, conducted on Jiaxian red cattle, harnessed whole transcriptome sequencing to unearth the nuances of circRNAs and miRNAs across seven distinct tissues. The interplay of these ncRNAs was assessed through differential expression analysis and network analysis. These findings are not only pivotal in unveiling the intricacies of fat deposition mechanisms but also lay a robust foundation for future research, setting the stage for enhancing IMF content in Jiaxian red cattle breeding.

Effectiveness of dyadic sensory art therapies for People with dementia and their caregivers:A systematic review and meta-analysis.

BACKGROUND: The need for dyadic intervention is enhanced with increasing numbers of older adults with dementia. Studies have shown that sensory art therapies are essential for dementia patients and their caregivers. The effects of dyadic sensory art therapies for people with dementia and their caregivers require further exploration. OBJECTIVES: This review aimed to assess the efficacy of dyadic sensory art therapies on neuropsychiatric symptoms and mental function for dementia patients, caregiver burden and psychological state for caregivers, dyad relationship quality for dyads, and evaluate the potential effects of dyadic sensory art therapies on quality of life for both dementia patients and caregivers. METHODS: An electronic literature search of the PubMed, EMBASE, CINAHL, Web of Science, Cochrane Library, PsycINFO and three Chinese databases (CNKI, Wanfang and CBM) was conducted up to November 2022. Two reviewers (SZ and QG) worked independently to identify relevant studies. Risk of bias was assessed by the Cochrane's and Joanna Briggs Institute's tool. Meta-analyses were conducted using RevMan software 5.4. RESULTS: This systematic review included 15 studies (7 RCTs and 8 quasi-experimental studies). The meta-analysis showed that dyadic sensory art therapies significantly ameliorated neuropsychiatric symptoms (SMD = -0.90, 95% CI -1.61 to -0.20, P = .01), caregiver burden (SMD = -0.75; 95% CI -1.03 to -0.47; P < .001). No significant improvements were found in caregiver depression and quality of life for both patients and caregivers. CONCLUSIONS: Dyadic sensory art therapies are generally effective at ameliorating neuropsychiatric symptoms, and caregiver burden. Future studies are encouraged to design large-scale randomized controlled trials with high-quality study to examine and confirm the effectiveness of dyadic sensory art therapies for these dyads composed of dementia patients and their caregivers. TRIAL REGISTRATION: PROSPERO CRD 42023393577; https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023393577.

Bta-miR-484 Targets SFRP1 and Affects Preadipocytes Proliferation, Differentiation, and Apoptosis.

MicroRNAs (miRNAs) are essential regulators of numerous biological processes in animals, including adipogenesis. Despite the abundance of miRNAs associated with adipogenesis, their exact mechanisms of action remain largely unknown. Our study highlights the role of bta-miR-484 as a major regulator of adipocyte proliferation, apoptosis, and differentiation. Here, we demonstrated that the expression of bta-miR-484 initially increased during adipogenesis before decreasing. Overexpression of bta-miR-484 in adipocytes ultimately inhibited cell proliferation and differentiation, reduced the number of EdU fluorescence-stained cells, increased the number of G1 phase cells, reduced the number of G2 and S phase cells, and downregulated the expression of proliferation markers (CDK2 and PCNA) and differentiation markers (CEBPA, FABP4, and LPL). Additionally, overexpression of bta-miR-484 promoted the expression of apoptosis-related genes (Caspase 3, Caspase 9, and BAX), and increased the number of apoptotic cells observed via flow cytometry. In contrast, bta-miR-484 inhibition in adipocytes yielded opposite effects to those observed during bta-miR-484 overexpression. Moreover, luciferase reporter assays confirmed SFRP1 as a target gene of bta-miR-484, and revealed that bta-miR-484 downregulates SFRP1 mRNA expression. These findings offer compelling evidence that bta-miR-484 targets SFRP1, inhibits proliferation and differentiation, and promotes apoptosis. Therefore, these results offer novel insights into the bta-miR-484 regulation of adipocyte growth and development.

Application of the wholebrain calculation interactive framework to map whole-brain neural connectivity networks.

The aim of this work was to develop a simple and feasible method of mapping the neural network topology of the mouse brain. Wild-type C57BL/6 J mice (n = 10) aged 8-10 weeks were injected with the cholera toxin subunit B (CTB) tracer in the anterior (NAcCA) and posterior (NAcCP) parts of the nucleus accumbens (NAc) core and in the medial (NAcSM) and lateral (NAcSL) parts of the NAc shell. The labeled neurons were reconstructed using the WholeBrain Calculation Interactive Framework. The NAcCA receives neuronal projections from the olfactory areas (OLF) and isocortex; the thalamus and isocortex project more fibers to the NAcSL, and the hypothalamus send more fiber projections to the NAcSM. Cell resolution can be automatically annotated, analyzed, and visualized using the WholeBrain Calculation Interactive Framework, making large-scale mapping of mouse brains at cellular and subcellular resolutions easier and more accurate.

The Suppressive Effect of Rebastinib on Triple-negative Breast Cancer Tumors Involves Multiple Mechanisms of Action.

BACKGROUND/AIM: High resistance of triple-negative breast cancer has prompted scientists to look for new targets susceptible to treatment. CDK16 has been suggested as a promising target whose inhibition can lead to tumor growth suppression. Rebastinib, a potent inhibitor of CDK16, has been reported to exhibit anti-tumor activity both in vitro and in vivo. MATERIALS AND METHODS: The anticancer activity of rebastinib was studied in vitro using cell proliferation, cell cycle arrest and cell apoptosis assays and in vivo in xenograft tumor models using MDA-MB-231 and MDA-MB-468-derived tumors. The safety and drug-like properties of rebastinib were assessed using a panel of Absorption, Distribution, Metabolism, and Excretion (ADME) assays, Ames tests, human Ether-a-go-go Related Gene (hERG) experiments and pharmacokinetic studies in mice and rats. RESULTS: Rebastinib demonstrates antitumor activity against breast cancer both in vitro and in vivo. However, the response of the tumor strongly depends on the type of triple-negative breast cancer. Rebastinib-induced cell cycle arrest was observed in G0/G1 phase suggesting a more complex mechanism than just CDK16 inhibition. ADME and PK studies confirmed the drug-like properties and reasonable safety of rebastinib. CONCLUSION: Our studies confirmed rebastinib to be a promising drug candidate for breast cancer treatment with high oral bioavailability and reasonable safety. Our data suggest that the mechanism of action of rebastinib is not limited to CDK16 inhibition but also involves other pathways. This does not diminish the importance of rebastinib as a drug candidate, but reveals the presence of several mechanisms, suggesting a wider scope of possible applications.

The engineered CRISPR-Mb2Cas12a variant enables sensitive and fast nucleic acid-based pathogens diagnostics in the field.

Existing CRISPR/Cas12a-based diagnostic platforms offer accurate and vigorous monitoring of nucleic acid targets, but have the potential to be further optimized for more efficient detection. Here, we profiled 16 Cas12a orthologs, focusing on their trans-cleavage activity and their potential as diagnostic enzymes. We observed the Mb2Cas12a has more robust trans-cleavage activity than other orthologs, especially at lower temperatures. An engineered Mb2Cas12a-RRVRR variant presented robust trans-cleavage activity and looser PAM constraints. Moreover, we found the existing one-pot assay, which simultaneously performed Recombinase Polymerase Amplification (RPA) and Cas12a reaction in one system, resulted in the loss of single-base discrimination during diagnosis. Therefore, we designed a reaction vessel that physically separated the RPA and Cas12a steps while maintaining a closed system. This isolated but closed system made diagnostics more sensitive and specific and effectively prevented contamination. This shelved Mb2Cas12a-RRVRR variant-mediated assay detected various targets in less than 15 min and exhibited equal or greater sensitivity than qPCR when detecting bacterial pathogens, plant RNA viruses and genetically modified crops. Overall, our findings further improved the efficiency of the current CRISPR-based diagnostic system and undoubtedly have great potential for highly sensitive and specific detection of multiple sample types.

Identification of key genes in bovine muscle development by co-expression analysis.

Background: Skeletal muscle is not only an important tissue involved in exercise and metabolism, but also an important part of livestock and poultry meat products. Its growth and development determines the output and quality of meat to a certain extent, and has an important impact on the economic benefits of animal husbandry. Skeletal muscle development is a complex regulatory network process, and its molecular mechanism needs to be further studied. Method: We used a weighted co-expression network (WGCNA) and single gene set enrichment analysis (GSEA) to study the RNA-seq data set of bovine tissue differential expression analysis, and the core genes and functional enrichment pathways closely related to muscle tissue development were screened. Finally, the accuracy of the analysis results was verified by tissue expression profile detection and bovine skeletal muscle satellite cell differentiation model in vitro (BSMSCs). Results: In this study, Atp2a1, Tmod4, Lmod3, Ryr1 and Mybpc2 were identified as marker genes in muscle tissue, which are mainly involved in glycolysis/gluconeogenesis, AMPK pathway and insulin pathway. The assay results showed that these five genes were highly expressed in muscle tissue and positively correlated with the differentiation of bovine BSMSCs. Conclusions: In this study, several muscle tissue characteristic genes were excavated, which may play an important role in muscle development and provide new insights for bovine molecular genetic breeding.

Genome-Wide Identification and Characterization of Bovine Fibroblast Growth Factor (FGF) Gene and Its Expression during Adipocyte Differentiation.

Fibroblast growth factor (FGF) family genes are a class of polypeptide factors with similar structures that play an important role in regulating cell proliferation and differentiation, nutritional metabolism, and neural activity. In previous studies, the FGF gene has been widely studied and analyzed in many species. However, the systematic study of the FGF gene in cattle has not been reported. In this study, 22 FGF genes distributed on 15 chromosomes were identified in the Bos taurus genome and clustered into seven subfamilies according to phylogenetic analysis and conservative domains. Collinear analysis showed that the bovine FGF gene family was homologous to Bos grunniens, Bos indicus, Hybrid-Bos taurus, Bubalus bubalis, and Hybrid-Bos indicus, and tandem replication and fragment replication were the key driving forces for the expansion of the gene family. Tissue expression profiling showed that bovine FGF genes were commonly expressed in different tissues, with FGF1, FGF5, FGF10, FGF12, FGF16, FGF17, and FGF20 being highly expressed in adipose tissue. In addition, real-time fluorescence quantitative PCR (qRT-PCR) detection showed that some FGF genes were differentially expressed before and after adipocyte differentiation, indicating their diverse role in the formation of lipid droplets. This study made a comprehensive exploration of the bovine FGF family and laid a foundation for further study on the potential function in the regulation of bovine adipogenic differentiation.

The expression of agmatinase manipulates the affective state of rats subjected to chronic restraint stress.

Agmatine is an endogenous polyamine produced from l-arginine and degraded by agmatinase (AGMAT). Studies in humans and animals have shown that agmatine has neuroprotective, anxiolytic, and antidepressant-like actions. However, little is known about the role of AGMAT in the action of agmatine or in the pathophysiology of psychiatric disorders. Therefore, this study aimed to investigate the role of AGMAT in the pathophysiology of MDD. In this study, we observed that AGMAT expression increased in the ventral hippocampus rather than in the medial prefrontal cortex in the chronic restraint stress (CRS) animal model of depression. Furthermore, we found that AGMAT overexpression in the ventral hippocampus elicited depressive- and anxiety-like behaviors, whereas knockdown of AGMAT exhibited antidepressant and anxiolytic effects in CRS animals. Field and whole-cell recordings of hippocampal CA1 revealed that AGMAT blockage increased Schaffer collateral-CA1 excitatory synaptic transmission, which was expressed both pre- and post-synaptically and was probably due to the inhibition of AGMAT-expressing local interneurons. Therefore, our results suggest that dysregulation of AGMAT is involved in the pathophysiology of depression and is a potential target for designing more effective antidepressants with fewer adverse effects to offer a better therapy for depression.

A self-assembled trimeric protein vaccine induces protective immunity against Omicron variant.

The recently emerged Omicron (B.1.1.529) variant has rapidly surpassed Delta to become the predominant circulating SARS-CoV-2 variant, given the higher transmissibility rate and immune escape ability, resulting in breakthrough infections in vaccinated individuals. A new generation of SARS-CoV-2 vaccines targeting the Omicron variant are urgently needed. Here, we developed a subunit vaccine named RBD-HR/trimer by directly linking the sequence of RBD derived from the Delta variant (containing L452R and T478K) and HR1 and HR2 in SARS-CoV-2 S2 subunit in a tandem manner, which can self-assemble into a trimer. In multiple animal models, vaccination of RBD-HR/trimer formulated with MF59-like oil-in-water adjuvant elicited sustained humoral immune response with high levels of broad-spectrum neutralizing antibodies against Omicron variants, also inducing a strong T cell immune response in vivo. In addition, our RBD-HR/trimer vaccine showed a strong boosting effect against Omicron variants after two doses of mRNA vaccines, featuring its capacity to be used in a prime-boost regimen. In mice and non-human primates, RBD-HR/trimer vaccination could confer a complete protection against live virus challenge of Omicron and Delta variants. The results qualified RBD-HR/trimer vaccine as a promising next-generation vaccine candidate for prevention of SARS-CoV-2, which deserved further evaluation in clinical trials.

Weighted Gene Co-Expression Network Analysis Identifies Key Modules and Central Genes Associated With Bovine Subcutaneous Adipose Tissue.

Background: Fat deposition is an important economic trait in livestock and poultry production. However, the relationship between various genes and signal pathways of fat deposition is still unclear to a large extent. The purpose of this study is to analyze the potential molecular targets and related molecular pathways in bovine subcutaneous adipose tissue. Results: We downloaded the GSE116775 microarray dataset from Gene Expression Omnibus (GEO). The weighted gene co-expression network (WGCNA) was used to analyze the gene expression profile, and the key gene modules with the highest correlation with subcutaneous adipose tissue were identified, and the functional enrichment of the key modules was analyzed. Then, the "real" Hub gene was screened by in-module analysis and protein-protein interaction network (PPI), and its expression level in tissue samples and adipocytes was verified. The study showed that a total of nine co-expression modules were identified, and the number of genes in these modules ranged from 101 to 1,509. Among them, the blue module is most closely related to subcutaneous adipose tissue, containing 1,387 genes. These genes were significantly enriched in 10 gene ontologies including extracellular matrix organization, biological adhesion, and collagen metabolic process, and were mainly involved in pathways including ECM-receptor interaction, focal adhesion, cAMP signaling pathway, PI3K-AKT signaling pathway, and regulation of lipolysis in adipocytes. In the PPI network and coexpression network, five genes (CAV1, ITGA5, COL5A1, ABL1, and HSPG2) were identified as "real" Hub genes. Analysis of Hub gene expression by dataset revealed that the expression of these Hub genes was significantly higher in subcutaneous adipose tissue than in other tissues. In addition, real-time fluorescence quantitative PCR (qRT-PCR) analysis based on tissue samples and adipocytes also confirmed the above results. Conclusion: In this study, five key genes related to subcutaneous adipose tissue were discovered, which laid a foundation for further study of the molecular regulation mechanism of subcutaneous adipose tissue development and adipose deposition.

Polymerized porin as a novel delivery platform for coronavirus vaccine.

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), seriously threatens human life and health. The correct folding and polymerization of the receptor-binding domain (RBD) protein of coronavirus in Escherichia coli may reduce the cost of SARS-CoV-2 vaccines. In this study, we constructed this nanopore by using the principle of ClyA porin polymerization triggered by the cell membrane. We used surfactants to "pick" the ClyA-RBD nanopore from the bacterial outer membrane. More importantly, the polymerized RBD displayed on the ClyA-RBD polymerized porin (RBD-PP) already displays some correct spatial conformational epitopes that can induce neutralizing antibodies. The nanostructures of RBD-PP can target lymph nodes and promote antigen uptake and processing by dendritic cells, thereby effectively eliciting the production of anti-SARS-CoV-2 neutralizing antibodies, systemic cellular immune responses, and memory T cells. We applied this PP-based vaccine platform to fabricate an RBD-based subunit vaccine against SARS-CoV-2, which will provide a foundation for the development of inexpensive coronavirus vaccines. The development of a novel vaccine delivery system is an important part of innovative drug research. This novel PP-based vaccine platform is likely to have additional applications, including other viral vaccines, bacterial vaccines, tumor vaccines, drug delivery, and disease diagnosis.

Histones released by NETosis enhance the infectivity of SARS-CoV-2 by bridging the spike protein subunit 2 and sialic acid on host cells.

Neutrophil extracellular traps (NETs) can capture and kill viruses, such as influenza viruses, human immunodeficiency virus (HIV), and respiratory syncytial virus (RSV), thus contributing to host defense. Contrary to our expectation, we show here that the histones released by NETosis enhance the infectivity of SARS-CoV-2, as found by using live SARS-CoV-2 and two pseudovirus systems as well as a mouse model. The histone H3 or H4 selectively binds to subunit 2 of the spike (S) protein, as shown by a biochemical binding assay, surface plasmon resonance and binding energy calculation as well as the construction of a mutant S protein by replacing four acidic amino acids. Sialic acid on the host cell surface is the key molecule to which histones bridge subunit 2 of the S protein. Moreover, histones enhance cell-cell fusion. Finally, treatment with an inhibitor of NETosis, histone H3 or H4, or sialic acid notably affected the levels of sgRNA copies and the number of apoptotic cells in a mouse model. These findings suggest that SARS-CoV-2 could hijack histones from neutrophil NETosis to promote its host cell attachment and entry process and may be important in exploring pathogenesis and possible strategies to develop new effective therapies for COVID-19.

Recombinant VLPs empower RBM peptides showing no immunogenicity in native SARS-COV-2 protein to elicit a robust neutralizing antibody response.

New SARS-COV-2 vaccine strategies are still urgently needed, especially for emerging virus mutations and variants. In this study, we focused on analyzing the antigenicity and vaccine potency of linear peptide epitopes located in receptor binding motif (RBM) of spike (S) protein. Nine 12 to 16-mer overlapping peptides (P1-P9) were synthesized chemically and coupled to carrier protein KLH for the immunization in mice. Four of identified peptides were further engineered to present on the surface of recombinant Hepatitis B core antigen (HBcAg) virus-like particles (VLPs) respectively. Antisera obtained from VLPs -immunized mice demonstrated strong reactivity and affinity to S1 protein or inactivated virus and neutralizing activity against virus infection in vitro. This study indicates that recombinant VLPs empower peptides which display underprivileged antigenicity in native protein to elicit high levels of neutralizing antibody, providing potential epitope candidates and an effective delivery strategy for the development of a multi-epitope vaccine.