XBiotech (United States)

Acute respiratory distress syndrome (ARDS) in COVID-19 has been associated with catastrophic inflammation. We present measurements in humans and a new animal model implicating a role in danger-associated molecular patterns. Calprotectin (S100A8/A9) and high-mobility group box 1 (HMGB1) were measured in patients without/with ARDS, and admission calprotectin was associated with soluble urokinase plasminogen activator receptor (suPAR). An animal model was developed by intravenous injection of plasma from healthy or patients with COVID-19 ARDS into C57/BL6 mice once daily for 3 consecutive days. Mice were treated with one anti-S100A8/A9 antibody, the IL-1 receptor antagonist anakinra or vehicle, and Flo1-2a anti-murine anti-IL-1α monoclonal antibody or the specific antihuman IL-1α antibody XB2001 or isotype controls. Cytokines and myeloperoxidase (MPO) were measured in tissues. Calprotectin, but not HMGB1, was elevated in ARDS. Higher suPAR indicated higher calprotectin. Animal challenge with COVID-19 plasma led to inflammatory reactions in murine lung and intestines as evidenced by increased levels of TNFα, IL-6, IFNγ, and MPO. Lung inflammation was attenuated with anti-S100A8/A9 pre-treatment. Anakinra treatment restored these levels. Similar decrease was found in mice treated with Flo1-2a but not with XB2001. Circulating alarmins, specifically calprotectin, of critically ill COVID-19 patients induces tissue-specific inflammatory responses through an IL-1-mediated mechanism. This could be attenuated through inhibition of IL-1 receptor or of IL-1α.

ABSTRACTBackgroundAcute respiratory distress syndrome (ARDS) in COVID-19 has been associated with dysregulated immune responses leading to catastrophic inflammation. The activation pathways remain to be fully elucidated. We investigated the ability of circulating to induce dysregulated immune responses.Materials & MethodsCalprotectin and high mobility group box 1 (HMGB1) were associated with ARDS in 60 COVID-19 patients. In a second cohort of 40 COVID-19 patients calprotectin at hospital admission was associated with serum levels of soluble urokinase plasminogen activator receptor (suPAR). A COVID-19 animal model was developed by intravenous injection of plasma from healthy volunteers or patients with COVID-19 ARDS into C57/BL6 mice once daily for 3 consecutive days. In separate experiments, mice were treated with a) the IL-1 receptor antagonist Anakinra or vehicle and b) Flo1-2a anti-murine anti-IL-1α monoclonal antibody or the specific anti-human IL-1α antibody XB2001, or isotype controls. Mice were sacrificed on day 4. Cytokines and myeloperoxidase (MPO) in tissues were measured.ResultsCalprotectin, but not HMGB1, was elevated ARDS. Higher suPAR readouts indicated higher calprotectin levels. CHallenge of mice with COVID-19 plasma led to inflammatory reactions in murine lung and intestines as evidenced by increased levels of TNFα, IL-6, IFNγ and MPO. Anakinra treatment brought these levels down. Similar decrease was found in mice treated with Flo1-2a but not with XB2001.ConclusionCirculating alarmins, specifically calprotectin, of critically ill COVID-19 patients induces tissue-specific inflammatory responses through an IL-1α mediated mechanism. This could be attenuated through inhibition of IL-1 receptor or specific inhibition of IL-1α.

Cks proteins are small evolutionarily conserved proteins that interact genetically and physically with cyclin-dependent kinases. However, in spite of a large body of genetic, biochemical and structural research, no compelling unifying model of their functions has emerged. Here we show, by investigating the essential role of Cks1 in Saccharomyces cerevisiae, that the protein is primarily involved in promoting mitosis by modulating the transcriptional activation of the APC/C protein-ubiquitin ligase activator Cdc20. Cks1 is required for both the periodic dissociation of Cdc28 kinase from the CDC20 promoter and the periodic association of the proteasome with the promoter. We propose that the essential role of Cks1 is to recruit the proteasome to, and/or dissociate the Cdc28 kinase from, the CDC20 promoter, thus facilitating transcription by remodelling transcriptional complexes or chromatin associated with the CDC20 gene.