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Abstract Toll-like receptor 7 (Tlr7) deficiency-accelerated severe COVID-19 is associated with reduced production of interferons (IFNs). However, the underlying mechanisms remain elusive. To address these questions, we utilize Tlr7 and Irf7 deficiency mice, single-cell RNA analysis together with bone marrow transplantation approaches. We demonstrate that at the early phase of infection, SARS-CoV-2 causes the upregulation of Tlr7, Irf7, and IFN pathways in the lungs of the infected mice. The deficiency of Tlr7 and Irf7 globally and/or in immune cells in mice increases the severity of COVID-19 via impaired IFN activation in both immune and/or non-immune cells, leading to increased lung viral loads. These effects are associated with reduced IFN alpha and gamma levels in the circulation. The deficiency of Tlr7 tends to cause the reduced production and nuclear translocation of interferon regulatory factor 7 (IRF7) in the lungs of the infected mice, indicative of reduced IRF7 activation. Despite higher amounts of lung viral antigen, Tlr7 or Irf7 deficiency resulted in substantially reduced production of antibodies against SARS-CoV-2, thereby delaying the viral clearance. These results highlight the importance of the activation of TLR7 and IRF7 leading to IFN production on the development of innate and adaptive immunity against COVID-19.

Abstract SARS-CoV-2 infection can cause persistent respiratory sequelae. However, the underlying mechanisms remain unclear. Here we report that sub-lethally infected K18-human ACE2 mice show patchy pneumonia associated with histiocytic inflammation and collagen deposition at 21 and 45 days post infection (DPI). Transcriptomic analyses revealed that compared to influenza-infected mice, SARS-CoV-2-infected mice had reduced interferon-gamma/alpha responses at 4 DPI and failed to induce keratin 5 (Krt5) at 6 DPI in lung, a marker of nascent pulmonary progenitor cells. Histologically, influenza- but not SARS-CoV-2-infected mice showed extensive Krt5+ “pods” structure co-stained with stem cell markers Trp63/NGFR proliferated in the pulmonary consolidation area at both 7 and 14 DPI, with regression at 21 DPI. These Krt5+ “pods” structures were not observed in the lungs of SARS-CoV-2-infected humans or nonhuman primates. These results suggest that SARS-CoV-2 infection fails to induce nascent Krt5+ cell proliferation in consolidated regions, leading to incomplete repair of the injured lung.

This study investigates the roles of T, B, and Natural Killer (NK) cells in the pathogenesis of severe COVID-19, utilizing mouse-adapted SARS-CoV-2-MA30 (MA30). To evaluate this MA30 mouse model, we characterized MA30-infected C57BL/6 mice (B6) and compared them with SARS-CoV-2-WA1 (an original SARS-CoV-2 strain) infected K18-human ACE2 (K18-hACE2) mice. We found that the infected B6 mice developed severe peribronchial inflammation and rapid severe pulmonary edema, but less lung interstitial inflammation than the infected K18-hACE2 mice. These pathological findings recapitulate some pathological changes seen in severe COVID-19 patients. Using this MA30-infected mouse model, we further demonstrate that T and/or B cells are essential in mounting an effective immune response against SARS-CoV-2. This was evident as Rag2−/− showed heightened vulnerability to infection and inhibited viral clearance. Conversely, the depletion of NK cells did not significantly alter the disease course in Rag2−/− mice, underscoring the minimal role of NK cells in the acute phase of MA30-induced disease. Together, our results indicate that T and/or B cells, but not NK cells, mitigate MA30-induced disease in mice and the infected mouse model can be used for dissecting the pathogenesis and immunology of severe COVID-19.

Abstract Background Systematic, high-throughput studies of mouse phenotypes have been hampered by the inability to analyze individual animal data from a multitude of sources in an integrated manner. Studies generally make comparisons at the level of genotype or treatment thereby excluding associations that may be subtle or involve compound phenotypes. Additionally, the lack of integrated, standardized ontologies and methodologies for data exchange has inhibited scientific collaboration and discovery. Results Here we introduce a Mouse Phenotype Analysis System (MPHASYS), a platform for integrating data generated by studies of mouse models of human biology and disease such as aging and cancer. This computational platform is designed to provide a standardized methodology for working with animal data; a framework for data entry, analysis and sharing; and ontologies and methodologies for ensuring accurate data capture. We describe the tools that currently comprise MPHASYS, primarily ones related to mouse pathology, and outline its use in a study of individual animal-specific patterns of multiple pathology in mice harboring a specific germline mutation in the DNA repair and transcription-specific gene Xpd. Conclusion MPHASYS is a system for analyzing multiple data types from individual animals. It provides a framework for developing data analysis applications, and tools for collecting and distributing high-quality data. The software is platform independent and freely available under an open-source license 1.

This study investigates the roles of T, B, and Natural Killer (NK) cells in the pathogenesis of severe COVID-19, utilizing mouse-adapted SARS-CoV-2-MA30 (MA30). To evaluate this MA30 mouse model, we characterized MA30-infected C57BL/6 mice (B6) and compared them with SARS-CoV-2-WA1 (an original SARS-CoV-2 strain) infected K18-human ACE2 (K18-hACE2) mice. We found that the infected B6 mice developed severe peribronchial inflammation and rapid severe pulmonary edema, but less lung interstitial inflammation than the infected K18-hACE2 mice. These pathological findings recapitulate some pathological changes seen in severe COVID-19 patients. Using this MA30-infected mouse model, we further demonstrate that T and/or B cells are essential in mounting an effective immune response against SARS-CoV-2. This was evident as Rag2−/− showed heightened vulnerability to infection and inhibited viral clearance. Conversely, the depletion of NK cells did not significantly alter the disease course in Rag2−/− mice, underscoring the minimal role of NK cells in the acute phase of MA30-induced disease. Together, our results indicate that T and/or B cells, but not NK cells, mitigate MA30-induced disease in mice and the infected mouse model can be used for dissecting the pathogenesis and immunology of severe COVID-19. [ABSTRACT FROM AUTHOR]

Author(s): Rumana Bahar [1]; Claudia H. Hartmann [2]; Karl A. Rodriguez [3]; Ashley D. Denny [3]; Rita A. Busuttil [1]; Martijn E. T. Dollé [4]; R. Brent Calder [1]; Gary [...]

Background: Cannabis is the second most commonly used substance after alcohol among people seeking treatment for other drug use, but no statistics are available regarding secondary cannabis use among drug treatment clients. Objectives: To investigate levels of secondary cannabis use among drug treatment clients and perceived need for support addressing this use among clients and staff. Methods: Cross-sectional surveys of clients (N = 295) and staff (N = 33) were conducted in 2015 at four London drug and alcohol treatment services. Client measures included recent drug use, type of cannabis used, Severity of Dependence Scale for cannabis, and views on secondary cannabis use treatment. Staff measures included definition of problem cannabis use, importance and timing for addressing secondary cannabis use. Results: Among clients, 39.7% reported recent secondary cannabis use, with 30.8% of these clients meeting criteria for problem use. Problem users were more likely to be interested in receiving treatment for cannabis use than non-problem users (51.4% versus 10.8%, p <.001). Nearly half of staff (48.5%) thought secondary cannabis use should be addressed early in treatment. Conclusions: Two out of five drug treatment clients used cannabis and a third experienced cannabis-related problems. Many are willing to address cannabis use, but defined treatment pathways are needed. [ABSTRACT FROM AUTHOR]

Check dams are used in gullies to prevent vertical downcutting of the thalweg. Check dams built as log crib structures are common in steep creeks prone to floods or debris floods. Recent experience with performance of log crib check dams subject to debris flow loadings is less common, as those check dams are often made from reinforced concrete, steel or masonry. This paper summarizes our experience with six log crib check dams built in a gully at East Gate Landslide, between Revelstoke and Golden, BC, Canada. The log crib check dams are subjected to multiple debris flow events every year. The project started as a pilot study and the design is adjusted before the next construction season, based on performance experience with previously built structures.