Respiratory mucosal delivery of next-generation COVID-19 vaccine provides robust protection against both ancestral and variant strains of SARS-CoV-2.

The emerging SARS-CoV-2 variants of concern (VOCs) threaten the effectiveness of current COVID-19 vaccines administered intramuscularly and designed to only target the spike protein. There is a pressing need to develop next-generation vaccine strategies for broader and long-lasting protection. Using adenoviral vectors (Ad) of human and chimpanzee origin, we evaluated Ad-vectored trivalent COVID-19 vaccines expressing spike-1, nucleocapsid, and RdRp antigens in murine models. We show that single-dose intranasal immunization, particularly with chimpanzee Ad-vectored vaccine, is superior to intramuscular immunization in induction of the tripartite protective immunity consisting of local and systemic antibody responses, mucosal tissue-resident memory T cells and mucosal trained innate immunity. We further show that intranasal immunization provides protection against both the ancestral SARS-CoV-2 and two VOC, B.1.1.7 and B.1.351. Our findings indicate that respiratory mucosal delivery of Ad-vectored multivalent vaccine represents an effective next-generation COVID-19 vaccine strategy to induce all-around mucosal immunity against current and future VOC.

Targeting the MR1-MAIT cell axis improves vaccine efficacy and affords protection against viral pathogens.

Mucosa-associated invariant T (MAIT) cells are MR1-restricted, innate-like T lymphocytes with tremendous antibacterial and immunomodulatory functions. Additionally, MAIT cells sense and respond to viral infections in an MR1-independent fashion. However, whether they can be directly targeted in immunization strategies against viral pathogens is unclear. We addressed this question in multiple wild-type and genetically altered but clinically relevant mouse strains using several vaccine platforms against influenza viruses, poxviruses and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We demonstrate that 5-(2-oxopropylideneamino)-6-D-ribitylaminouracil (5-OP-RU), a riboflavin-based MR1 ligand of bacterial origin, can synergize with viral vaccines to expand MAIT cells in multiple tissues, reprogram them towards a pro-inflammatory MAIT1 phenotype, license them to bolster virus-specific CD8+ T cell responses, and potentiate heterosubtypic anti-influenza protection. Repeated 5-OP-RU administration did not render MAIT cells anergic, thus allowing for its inclusion in prime-boost immunization protocols. Mechanistically, tissue MAIT cell accumulation was due to their robust proliferation, as opposed to altered migratory behavior, and required viral vaccine replication competency and Toll-like receptor 3 and type I interferon receptor signaling. The observed phenomenon was reproducible in female and male mice, and in both young and old animals. It could also be recapitulated in a human cell culture system in which peripheral blood mononuclear cells were exposed to replicating virions and 5-OP-RU. In conclusion, although viruses and virus-based vaccines are devoid of the riboflavin biosynthesis machinery that supplies MR1 ligands, targeting MR1 enhances the efficacy of vaccine-elicited antiviral immunity. We propose 5-OP-RU as a non-classic but potent and versatile vaccine adjuvant against respiratory viruses.

Type I interferon regulates proteolysis by macrophages to prevent immunopathology following viral infection.

The ability to treat severe viral infections is limited by our understanding of the mechanisms behind virus-induced immunopathology. While the role of type I interferons (IFNs) in early control of viral replication is clear, less is known about how IFNs can regulate the development of immunopathology and affect disease outcomes. Here, we report that absence of type I IFN receptor (IFNAR) is associated with extensive immunopathology following mucosal viral infection. This pathology occurred independent of viral load or type II immunity but required the presence of macrophages and IL-6. The depletion of macrophages and inhibition of IL-6 signaling significantly abrogated immunopathology. Tissue destruction was mediated by macrophage-derived matrix metalloproteinases (MMPs), as MMP inhibition by doxycycline and Ro 28-2653 reduced the severity of tissue pathology. Analysis of post-mortem COVID-19 patient lungs also displayed significant upregulation of the expression of MMPs and accumulation of macrophages. Overall, we demonstrate that IFNs inhibit macrophage-mediated MMP production to prevent virus-induced immunopathology and uncover MMPs as a therapeutic target towards viral infections.

Cytomegalovirus Seropositivity in Older Adults Changes the T Cell Repertoire but Does Not Prevent Antibody or Cellular Responses to SARS-CoV-2 Vaccination.

Chronic infection with human CMV may contribute to poor vaccine efficacy in older adults. We assessed the effects of CMV serostatus on Ab quantity and quality, as well as cellular memory recall responses, after two and three SARS-CoV-2 mRNA vaccine doses, in older adults in assisted living facilities. CMV serostatus did not affect anti-Spike and anti-receptor-binding domain IgG Ab levels, nor neutralization capacity against wild-type or ß variants of SARS-CoV-2 several months after vaccination. CMV seropositivity altered T cell expression of senescence-associated markers and increased effector memory re-expressing CD45RA T cell numbers, as has been previously reported; however, this did not impact Spike-specific CD4+ T cell memory recall responses. CMV-seropositive individuals did not have a higher incidence of COVID-19, although prior infection influenced humoral immunity. Therefore, CMV seropositivity may alter T cell composition but does not impede the durability of humoral protection or cellular memory responses after SARS-CoV-2 mRNA vaccination in older adults.

A liposome-displayed hemagglutinin vaccine platform protects mice and ferrets from heterologous influenza virus challenge.

Recombinant influenza virus vaccines based on hemagglutinin (HA) hold the potential to accelerate production timelines and improve efficacy relative to traditional egg-based platforms. Here, we assess a vaccine adjuvant system comprised of immunogenic liposomes that spontaneously convert soluble antigens into a particle format, displayed on the bilayer surface. When trimeric H3 HA was presented on liposomes, antigen delivery to macrophages was improved in vitro, and strong functional antibody responses were induced following intramuscular immunization of mice. Protection was conferred against challenge with a heterologous strain of H3N2 virus, and naive mice were also protected following passive serum transfer. When admixed with the particle-forming liposomes, immunization reduced viral infection severity at vaccine doses as low as 2 ng HA, highlighting dose-sparing potential. In ferrets, immunization induced neutralizing antibodies that reduced the upper respiratory viral load upon challenge with a more modern, heterologous H3N2 viral strain. To demonstrate the flexibility and modular nature of the liposome system, 10 recombinant surface antigens representing distinct influenza virus strains were bound simultaneously to generate a highly multivalent protein particle that with 5 ng individual antigen dosing induced antibodies in mice that specifically recognized the constituent immunogens and conferred protection against heterologous H5N1 influenza virus challenge. Taken together, these results show that stable presentation of recombinant HA on immunogenic liposome surfaces in an arrayed fashion enhances functional immune responses and warrants further attention for the development of broadly protective influenza virus vaccines.

Sensitivity to Neutralizing Antibodies and Resistance to Type I Interferons in SARS-CoV-2 R.1 Lineage Variants, Canada.

Isolating and characterizing emerging SARS-CoV-2 variants is key to understanding virus pathogenesis. In this study, we isolated samples of the SARS-CoV-2 R.1 lineage, categorized as a variant under monitoring by the World Health Organization, and evaluated their sensitivity to neutralizing antibodies and type I interferons. We used convalescent serum samples from persons in Canada infected either with ancestral virus (wave 1) or the B.1.1.7 (Alpha) variant of concern (wave 3) for testing neutralization sensitivity. The R.1 isolates were potently neutralized by both the wave 1 and wave 3 convalescent serum samples, unlike the B.1.351 (Beta) variant of concern. Of note, the R.1 variant was significantly more resistant to type I interferons (IFN-α/ß) than was the ancestral isolate. Our study demonstrates that the R.1 variant retained sensitivity to neutralizing antibodies but evolved resistance to type I interferons. This critical driving force will influence the trajectory of the pandemic.

Early humoral and cellular responses after bivalent SARS-CoV-2 mRNA-1273.214 vaccination in long-term care and retirement home residents in Ontario, Canada: An observational cohort study.

Immunogenicity of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) bivalent mRNA-1273.214 vaccine (Original/Omicron B.1.1.529 [BA.1]) is underreported in vulnerable older adults in congregate care settings. In residents of 26 long-term care and retirement homes in Ontario, Canada, humoral (i.e., serum anti-spike and anti-receptor binding domain [anti-RBD]) IgG and IgA antibodies and live SARS-CoV-2 neutralization) and cellular (i.e., CD4+ and CD8+ activation-induced marker spike-specific T cell memory) responses were assessed 7-120 days postvaccination with four monovalent mRNA vaccines (n = 494) or subsequent bivalent mRNA-1273.214 vaccination (fifth vaccine) (n = 557). Within 4 months, anti-spike and anti-RBD antibody levels were similar after monovalent and bivalent vaccination in infection-naïve individuals. Hybrid immunity (i.e., vaccination and natural infection) generally increased humoral responses. After bivalent vaccination, compared to monovalent vaccination, residents with hybrid immunity had elevated anti-spike and anti-RBD IgG and IgA antibodies. Omicron BA.1 antibody-mediated neutralization, and CD8+ T cell memory responses to the Omicron BA.1 spike protein, were also higher after bivalent vaccination. Humoral and cellular responses were, therefore, noninferior within 4 months of bivalent mRNA-1273.214 vaccination compared to monovalent mRNA vaccination. Waning of humoral but not cellular immunity was particularly evident in individuals without hybrid immunity. Continued monitoring of vaccine-associated and hybrid immunity against emerging Omicron variants of concern is necessary to assess longevity of protection.

Covalent Stabilization of Antibody Recruitment Enhances Immune Recognition of Cancer Targets.

Antibody recruiting molecules (ARMs) represent an important class of "proximity-inducing" chemical tools with therapeutic potential. ARMs function by simultaneously binding to a hapten-specific serum antibody (Ab) (e.g., anti-dinitrophenyl (DNP)) and a cancer cell surface protein, enforcing their proximity. ARM anticancer efficacy depends on the formation of ARM:Ab complexes on the cancer cell surface, which activate immune cell recognition and elimination of the cancer cell. Problematically, ARM function in human patients may be limited by conditions that drive the dissociation of ARM:Ab complexes, namely, intrinsically low binding affinity and/or low concentrations of anti-hapten antibodies in human serum. To address this potential limitation, we previously developed a covalent ARM (cARM) chemical tool that eliminates the ARM:antibody equilibrium through a covalent linkage. In the current study, we set out to determine to what extent maximizing the stability of ARM:antibody complexes via cARMs enhances target immune recognition. We observe cARMs significantly increase target immune recognition relative to ARMs across a range of therapeutically relevant antibody concentrations. These results demonstrate that ARM therapeutic function can be dramatically enhanced by increasing the kinetic stability of ARM:antibody complexes localized on cancer cells. Our findings suggest that a) high titres/concentrations of target antibody in human serum are not neccessary and b) saturative antibody recruitment to cancer cells not sufficient, to achieve maximal ARM therapeutic function.

Original Antigenic Sin: How First Exposure Shapes Lifelong Anti-Influenza Virus Immune Responses.

The term "original antigenic sin" (OAS) was first used in the 1960s to describe how one's first exposure to influenza virus shapes the outcome of subsequent exposures to antigenically related strains. In the decades that have passed, OAS-like responses have been shown to play an integral role in both protection from and susceptibility to infections. OAS may also have an important deterministic role in the differential efficacy of influenza vaccine responses observed for various age cohorts across seasons. In this article, we review how the understanding of OAS has progressed from its initial description and highlight important outstanding questions in need of further study.

Mimicry of Cellular A Kinase-Anchoring Proteins Is a Conserved and Critical Function of E1A across Various Human Adenovirus Species.

The E1A proteins of the various human adenovirus (HAdV) species perform the critical task of converting an infected cell into a setting primed for virus replication. While E1A proteins differ in both sequence and mechanism, the evolutionary pressure on viruses with limited coding capacity ensures that these proteins often have significant overlap in critical functions. HAdV-5 E1A is known to use mimicry to rewire cyclic AMP (cAMP) signaling by decoupling protein kinase A (PKA) from cellular A kinase-anchoring proteins (AKAPs) and utilizing PKA to its own advantage. We show here that E1As from other species of HAdV also possess this viral AKAP (vAKAP) function and examine how they manipulate PKA. E1A from most species of HAdV examined contain a small AKAP-like motif in their N terminus which targets the docking-dimerization domain of PKA as the binding interface for a conserved protein-protein interaction. This motif is also responsible for an E1A-mediated relocalization of PKA regulatory subunits from the cytoplasm into the nucleus, with species-specific E1A proteins having preference for one particular isoform of PKA subunit over another. Importantly, we showed that these newly characterized vAKAPs can integrate into cAMP-responsive transcription as well as contribute to viral genome replication and infectious progeny production for several distinct HAdV species.IMPORTANCE These data enhance the mechanistic knowledge on how HAdV E1A manipulates cellular PKA to benefit infection. The work establishes that mimicry of AKAPs and subversion of PKA-mediated cAMP signaling are conserved features for numerous human adenoviruses. This study also highlights the molecular determinants conferring selective protein-protein interactions between distinct PKA regulatory subunits and the different E1A proteins of these viruses. Additionally, it further emphasizes the utility of using viral proteins like E1A as tools for studying the molecular biology of cellular regulatory pathways.

Linc-RoR promotes c-Myc expression through hnRNP I and AUF1.

Linc-RoR was originally identified to be a regulator for induced pluripotent stem cells in humans and it has also been implicated in tumorigenesis. However, the underlying mechanism of Linc-RoR-mediated gene expression in cancer is poorly understood. The present study demonstrates that Linc-RoR plays an oncogenic role in part through regulation of c-Myc expression. Linc-RoR knockout (KO) suppresses cell proliferation and tumor growth. In particular, Linc-RoR KO causes a significant decrease in c-Myc whereas re-expression of Linc-RoR in the KO cells restores the level of c-Myc. Mechanistically, Linc-RoR interacts with heterogeneous nuclear ribonucleoprotein (hnRNP) I and AU-rich element RNA-binding protein 1 (AUF1), respectively, with an opposite consequence to their interaction with c-Myc mRNA. While Linc-RoR is required for hnRNP I to bind to c-Myc mRNA, interaction of Linc-RoR with AUF1 inhibits AUF1 to bind to c-Myc mRNA. As a result, Linc-RoR may contribute to the increased stability of c-Myc mRNA. Although hnRNP I and AUF1 can interact with many RNA species and regulate their functions, with involvement of Linc-RoR they would be able to selectively regulate mRNA stability of specific genes such as c-Myc. Together, these results support a role for Linc-RoR in c-Myc expression in part by specifically enhancing its mRNA stability, leading to cell proliferation and tumorigenesis.

LncRNA loc285194 is a p53-regulated tumor suppressor.

Protein-coding genes account for only a small part of the human genome, whereas the vast majority of transcripts make up the non-coding RNAs including long non-coding RNAs (lncRNAs). Accumulating evidence indicates that lncRNAs could play a critical role in regulation of cellular processes such as cell growth and apoptosis as well as cancer progression and metastasis. LncRNA loc285194 was previously shown to be within a tumor suppressor unit in osteosarcoma and to suppress tumor cell growth. However, it is unknown regarding the regulation of loc285194. Moreover, the underlying mechanism by which loc285194 functions as a potential tumor suppressor is elusive. In this study, we show that loc285194 is a p53 transcription target; ectopic expression of loc285194 inhibits tumor cell growth both in vitro and in vivo. Through deletion analysis, we identify an active region responsible for tumor cell growth inhibition within exon 4, which harbors two miR-211 binding sites. Importantly, this loc285194-mediated growth inhibition is in part due to specific suppression of miR-211. We further demonstrate a reciprocal repression between loc285194 and miR-211; in contrast to loc285194, miR-211 promotes cell growth. Finally, we detect downregulation of loc285194 in colon cancer specimens by quantitative PCR arrays and in situ hybridization of tissue microarrays. Together, these results suggest that loc285194 is a p53-regulated tumor suppressor, which acts in part through repression of miR-211.

Host genotype-specific rhizosphere fungus enhances drought resistance in wheat.

BACKGROUND: The severity and frequency of drought are expected to increase substantially in the coming century and dramatically reduce crop yields. Manipulation of rhizosphere microbiomes is an emerging strategy for mitigating drought stress in agroecosystems. However, little is known about the mechanisms underlying how drought-resistant plant recruitment of specific rhizosphere fungi enhances drought adaptation of drought-sensitive wheats. Here, we investigated microbial community assembly features and functional profiles of rhizosphere microbiomes related to drought-resistant and drought-sensitive wheats by amplicon and shotgun metagenome sequencing techniques. We then established evident linkages between root morphology traits and putative keystone taxa based on microbial inoculation experiments. Furthermore, root RNA sequencing and RT-qPCR were employed to explore the mechanisms how rhizosphere microbes modify plant response traits to drought stresses. RESULTS: Our results indicated that host plant signature, plant niche compartment, and planting site jointly contribute to the variation of soil microbiome assembly and functional adaptation, with a relatively greater effect of host plant signature observed for the rhizosphere fungi community. Importantly, drought-resistant wheat (Yunhan 618) possessed more diverse bacterial and fungal taxa than that of the drought-sensitive wheat (Chinese Spring), particularly for specific fungal species. In terms of microbial interkingdom association networks, the drought-resistant variety possessed more complex microbial networks. Metagenomics analyses further suggested that the enriched rhizosphere microbiomes belonging to the drought-resistant cultivar had a higher investment in energy metabolism, particularly in carbon cycling, that shaped their distinctive drought tolerance via the mediation of drought-induced feedback functional pathways. Furthermore, we observed that host plant signature drives the differentiation in the ecological role of the cultivable fungal species Mortierella alpine (M. alpina) and Epicoccum nigrum (E. nigrum). The successful colonization of M. alpina on the root surface enhanced the resistance of wheats in response to drought stresses via activation of drought-responsive genes (e.g., CIPK9 and PP2C30). Notably, we found that lateral roots and root hairs were significantly suppressed by co-colonization of a drought-enriched fungus (M. alpina) and a drought-depleted fungus (E. nigrum). CONCLUSIONS: Collectively, our findings revealed host genotypes profoundly influence rhizosphere microbiome assembly and functional adaptation, as well as it provides evidence that drought-resistant plant recruitment of specific rhizosphere fungi enhances drought tolerance of drought-sensitive wheats. These findings significantly underpin our understanding of the complex feedbacks between plants and microbes during drought, and lay a foundation for steering "beneficial keystone biome" to develop more resilient and productive crops under climate change. Video Abstract.

Beyond neutralization: Fc-dependent antibody effector functions in SARS-CoV-2 infection.

Neutralizing antibodies are known to have a crucial role in protecting against SARS-CoV-2 infection and have been suggested to be a useful correlate of protection for vaccine clinical trials and for population-level surveys. In addition to neutralizing virus directly, antibodies can also engage immune effectors through their Fc domains, including Fc receptor-expressing immune cells and complement. The outcome of these interactions depends on a range of factors, including antibody isotype-Fc receptor combinations, Fc receptor-bearing cell types and antibody post-translational modifications. A growing body of evidence has shown roles for these Fc-dependent antibody effector functions in determining the outcome of SARS-CoV-2 infection. However, measuring these functions is more complicated than assays that measure antibody binding and virus neutralization. Here, we examine recent data illuminating the roles of Fc-dependent antibody effector functions in the context of SARS-CoV-2 infection, and we discuss the implications of these data for the development of next-generation SARS-CoV-2 vaccines and therapeutics.

Diversity in MD-PhD Programs and Factors Affecting Admission and Completion Among Minoritized Groups: A Scoping Review.

PURPOSE: To improve awareness of diversity in MD-PhD program applicants, matriculants, and graduates; facilitators and barriers to matriculation and/or completion among minoritized groups; and the effects of research experience programs on admissions processes aimed to increase representation of minoritized groups in MD-PhD programs. METHOD: The authors conducted a scoping review, searching EMBASE, MEDLINE, PsycINFO, CINAHL, and Web of Science through December 21, 2021, for studies that contained data on the characteristics of MD-PhD learners and initiatives aimed to make the clinician-scientist trainee population more diverse. They excluded studies that had no primary data, were unavailable in English, and were not peer-reviewed. RESULTS: Of 4,369 articles identified, 16 met inclusion criteria. Studies conceptualized diversity inconsistently, including as sex/gender disparities (n = 11), race/ethnicity underrepresentation (n = 9), disability (n = 2), first-generation student (n = 1), visible minority (n = 1), Indigenous population (n = 1), and economic/social disadvantage (n = 1). Potential barriers to entering or continuing in an MD-PhD program among women and underrepresented ethnic minorities included the long program duration and lack of mentorship; potential facilitators included the flexibility of the dual-degree program. Limited data on high school, undergraduate, and postbaccalaureate research experience programs targeting underrepresented minorities suggest that they may help facilitate admission into MD-PhD programs. CONCLUSIONS: The findings of this scoping review suggest that the diversity of MD-PhD students has been conceptualized in unitary, inconsistent terms, without addressing how different dimensions of diversity may intersect and impact MD-PhD admissions. Future studies should be explicit and intentional in defining "diversity" as it relates to their research questions, explore the impact of intersectionality, and systematically identify and address causal facilitators and barriers of entry to and completion of MD-PhD programs among minoritized groups.

ASK1 inhibitors are potential pan-antiviral drugs, which dampen replication of diverse viruses including SARS-CoV2.

Apoptosis signal-regulating kinase 1 (ASK1)/MAP3K5 is a stress response kinase that is activated by various stimuli. It is known as an upstream activator of p38- Mitogen-activated protein kinase (p38MAPK) and c-Jun N-terminal kinase (JNK) that are reactive oxygen species (ROS)-induced kinases. Accumulating evidence show that ROS accumulate in virus-infected cells. Here, we investigated the relationship between viruses and ASK1/p38MAPK or ASK1/JNK pathways. Our findings suggest that virus infection activates ASK1 related pathways. In parallel, ASK1 inhibition led to a remarkable reduction in the replication of a broad range of viruses including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), vaccinia virus (VV), vesicular stomatitis virus (VSV), Herpes Simplex Virus (HSV), and Human Immunodeficiency virus (HIV) in different human cell lines. Our work demonstrates the potential therapeutic use of Selonsertib, an ASK1 inhibitor, as a pan-antiviral drug in humans. Surprisingly, we observed differential effects of Selonsertib in in vitro and in vivo hamster models, suggesting caution in using rodent models to predict clinical and therapeutic outcomes in humans.

Comparison of three dosing intervals for the primary vaccination of the SARS-CoV-2 mRNA Vaccine (BNT162b2) on magnitude, neutralization capacity and durability of the humoral immune response in health care workers: A prospective cohort study.

OBJECTIVES: The dosing interval of a primary vaccination series can significantly impact on vaccine immunogenicity and efficacy. The current study compared 3 dosing intervals for the primary vaccination series of the BNT162b2 mRNA COVID-19 vaccine, on humoral immune response and durability against SARS-CoV-2 ancestral and Beta variants up to 9 months post immunization. METHODS: Three groups of age- and sex-matched healthcare workers (HCW) who received 2 primary doses of BNT162b2 separated by 35-days, 35-42 days or >42-days were enrolled. Vaccine induced antibody titers at 3 weeks, 3 and 6-9 months post-second dose were assessed. RESULTS: There were 309 age- and sex-matched HCW (mean age 43 [sd 13], 58% females) enrolled. Anti-SARS-CoV-2 binding (IgG, IgM, IgA) and neutralizing antibody titers showed significant waning in levels beyond 35 days post first dose. The second dose induced a significant rise in antibody titers, which peaked at 3 weeks and then declined at variable rates across groups. The magnitude, consistency and durability of response was greater for anti-Spike than anti-RBD antibodies; and for IgG than IgA or IgM. Compared to the shorter schedules, a longer interval of >42 days offered the highest binding and neutralizing antibody titers against SARS-CoV-2 ancestral and Beta (B1.351) variants beyond 3 months post-vaccination. CONCLUSIONS: This is the first comprehensive study to compare 3 dosing intervals for the primary vaccination of BNT162b2 mRNA COVID-19 vaccine implemented in the real world. These findings suggest that delaying the second dose beyond 42 days can potentiate and prolong the humoral response against ancestral and Beta variants of SARS-CoV-2 up to 9 months post-vaccination.

Early Omicron infection is associated with increased reinfection risk in older adults in long-term care and retirement facilities.

Background: Older adults are at increased risk of SARS-CoV-2 Omicron infection and severe disease, especially those in congregate living settings, despite high SARS-CoV-2 vaccine coverage. It is unclear whether hybrid immunity (combined vaccination and infection) after one Omicron infection provides increased protection against subsequent Omicron reinfection in older adults. Methods: Incidence of SARS-CoV-2 Omicron infection was examined in 750 vaccinated residents of long-term care and retirement homes in the observational cohort COVID in Long-Term Care Study in Ontario, Canada, within a 75-day period (July to September 2022). Risk of infection was assessed by Cox proportional hazards regression. Serum anti-spike and anti-RBD SARS-CoV-2 IgG and IgA antibodies, microneutralization titres, and spike-specific T cell memory responses, were examined in a subset of 318 residents within the preceding three months. Findings: 133 of 750 participants (17.7%) had a PCR-confirmed Omicron infection during the observation period. Increased infection risk was associated with prior Omicron infection (at 9-29 days: 47.67 [23.73-95.76]), and this was not attributed to days since fourth vaccination (1.00 [1.00-1.01]) or residence outbreaks (>6 compared to ≤6: 0.95 [0.37-2.41]). Instead, reinfected participants had lower serum neutralizing antibodies to ancestral and Omicron BA.1 SARS-CoV-2, and lower anti-RBD IgG and IgA antibodies, after their initial Omicron infection. Interpretation: Counterintuitively, SARS-CoV-2 Omicron infection was associated with increased risk of Omicron reinfection in residents of long-term care and retirement homes. Less robust humoral hybrid immune responses in older adults may contribute to risk of Omicron reinfection. Funding: COVID-19 Immunity Task Force of the Public Health Agency of Canada.

ROCK cooperated with ET-1 to induce epithelial to mesenchymal transition through SLUG in human ovarian cancer cells.

The Rho-associated serine-threonine protein kinase (ROCK) is a downstream effector of Rho GTPases that is frequently activated in the epithelial to mesenchymal transition (EMT) of human ovarian cancer cells. On the other hand, endothelin-1 (ET-1) and its receptor endothelin A receptor (ET(A)R) are overexpressed in primary and metastatic ovarian carcinoma, which suggests that ET-1 promotes tumor dissemination. Hence, two human ovarian carcinoma cell lines, SK-OV-3 and CaOV3, were chosen to study the effects of ET-1/ET(A)R and ROCK in promoting EMT of ovarian cancer cells. We found that ET-1 exposure induced EMT of SK-OV-3 and CaOV3 by monitoring cells morphology, enhanced fibronectin, and reduced E-cadherin protein. At the same time, ET-1/ET(A)R enhanced the level of transcription of SLUG a transcriptional repressor of E-cadherin. More importantly, a constitutively active mutant of ROCK enhanced the transcription of SLUG by stimulating SLUG promoter activity. Furthermore, ROCK inhibitor Y27632 reversed the increase in fibronectin induced by ET-1/ET(A)R. Our data suggest that ROCK cooperated with ET-1/ET(A)R to promote EMT of human ovarian carcinoma cells through upregulation of SLUG mRNA.

Tunicate inspired gelatin-based tough hydrogel wound dressing containing twisted phthalazinone with adhesive, self-healing and antibacterial properties.

As a hydrolytic product of collagen, gelatin is a polypeptide of biological origin. Gelatin hydrogels emerge as promising material candidates for traditional dressings due to good biocompatibility and the ability to keep wounds moist. However, it is difficult to simultaneously achieve gelatin hydrogel with robust mechanical property for long-term usage, reliable tissue adhesion, self-healing and antibacterial properties. Herein, we propose a simply synthesized strategy of a multifunctional gelatin hydrogel dressing, which is constructed by conjugating a newly synthesized 2-(4'-aldehydephenyl)-4-(2',3',4'-trihydroxyphenyl)-2,3-phthalazine-1(2H)-one (THPZB) to gelatin with Schiff base and chelating with Fe3+ ions (termed G/THPZB/Fe hydrogel). The twisted structure of phthalazinone in THPZB leads to entanglement of gelatin molecular chains, which resolves the stiffness-toughness conflict of the hydrogel. Furthermore, the strong tissue adhesion and fast self-healing capability mainly originate from the hydrogen bonding of the pyrogallol in THPZB. In vitro study shows that the hydrogels possess good biocompatibility with L929 cells, hemostatic and antibacterial activity. In the rat model of skin infection, the hydrogel dressing not only have no adverse effects on vital organs, but also can effectively promote wound healing of bacterial infection. Considering that it has multiple functions, G/THPZB/Fe hydrogel can be used as a promising wound dressing for biomedical applications.