Patients with severe COVID-19 have a hyperinflammatory immune response suggestive of macrophage activation. Bruton tyrosine kinase (BTK) regulates macrophage signaling and activation. Acalabrutinib, a selective BTK inhibitor, was administered off-label to 19 patients hospitalized with severe COVID-19 (11 on supplemental oxygen; 8 on mechanical ventilation), 18 of whom had increasing oxygen requirements at baseline. Over a 10-14 day treatment course, acalabrutinib improved oxygenation in a majority of patients, often within 1-3 days, and had no discernable toxicity. Measures of inflammation – C-reactive protein and IL-6 – normalized quickly in most patients, as did lymphopenia, in correlation with improved oxygenation. At the end of acalabrutinib treatment, 8/11 (72.7%) patients in the supplemental oxygen cohort had been discharged on room air, and 4/8 (50%) patients in the mechanical ventilation cohort had been successfully extubated, with 2/8 (25%) discharged on room air. Ex vivo analysis revealed significantly elevated BTK activity, as evidenced by autophosphorylation, and increased IL-6 production in blood monocytes from patients with severe COVID-19 compared with blood monocytes from healthy volunteers. These results suggest that targeting excessive host inflammation with a BTK inhibitor is a therapeutic strategy in severe COVID-19 and has led to a confirmatory international prospective randomized controlled clinical trial.

Protein arginine N-methyltransferases have been implicated in a variety of processes, including cell proliferation, signal transduction, and protein trafficking. In this study, we have characterized essentially a null mutation induced by insertion of the U3␤Geo gene trap retrovirus into the second intron of the mouse protein arginine N-methyltransferase 1 gene (Prmt1). cDNAs encoding two forms of Prmt1 were characterized, and the predicted protein sequences were found to be highly conserved among vertebrates. Expression of the Prmt1-␤geo fusion gene was greatest along the midline of the neural plate and in the forming head fold from embryonic day 7.5 (E7.5) to E8.5 and in the developing central nervous system from E8.5 to E13.5. Homozygous mutant embryos failed to develop beyond E6.5, a phenotype consistent with a fundamental role in cellular metabolism. However, Prmt1 was not required for cell viability, as the protein was not detected in embryonic stem (ES) cell lines established from mutant blastocysts. Low levels of Prmt1 transcripts (approximately 1% of the wild-type level) were detected as assessed by a quantitative reverse transcription-PCR assay. Total levels of arginine N-methyltransferase activity and asymmetric N G ,N G -dimethylarginine were reduced by 85 and 54%, respectively, while levels of hypomethylated substrates were increased 15-fold. Prmt1 appears to be a major type I enzyme in ES cells, and in wild-type cells, most substrates of the enzyme appear to be maintained in a fully methylated state.Methylation of arginine residues is one of many covalent modifications of eukaryotic proteins that occur concomitant with or shortly following translation. Two types of protein arginine methyltransferases have been classified according to their substrate specificity and reaction products (reviewed in reference 11). Type I enzymes catalyze the formation of N G -monomethylarginine and asymmetric N G ,N G -dimethylarginine, while type II enzymes catalyze the formation of N Gmonomethylarginine and symmetric N G ,NЈ G -dimethylarginine. Most substrates for type I enzymes bind nucleic acid, usually RNA. These include heterogeneous nuclear RNA binding proteins (hnRNPs), which collectively contain 65% of the nuclear asymmetric dimethylarginine, as well as fibrillarin and nucleolin (19-21). The only known physiological substrate of symmetric (type II) arginine methyltransferase is myelin basic protein, a major protein component of the myelin sheath.Genes encoding rat (PRMT1), human (HRMT1L2), and yeast (RMT1) type I enzymes have been characterized (12,13,17,29). The mammalian genes appear to be ubiquitously expressed in all tissues (17, 29, 32). The yeast enzyme, which is not required for cell viability, accounts for over 85% of the protein dimethylarginine in the cell (12).Type I enzymes have been implicated in a variety of processes, including cell growth control, signal transduction, and protein trafficking, but the biochemical and biological functions of arginine methylation have not been established. The enz...

The present study characterized an embryonic lethal mutation induced by insertion of the U3Neo gene trap retrovirus into an intron of the gene encoding heterogeneous ribonuclear protein U (Hnrnpu), which maps to the distal arm of mouse chromosome 1. Murine hnRNP U was found to be identical to the human protein at all but one of 341 amino acid residues. Embryos homozygous for the provirus showed obvious abnormalities after 6.5 days of development (E6.5) and were resorbed by E10.5. Expression of the inserted neomycin-resistance gene involved alternative splicing to a cryptic 3' splice site located in the neomycin resistance gene resulting in a hypomorphic mutation. Homozygous mutant cell lines isolated from preimplantation blastocysts expressed hnRNP U transcripts at levels 2 to 5 times lower than wild-type cells, suggesting that nearly wild-type levels of hnRNP U are required for embryonic development.

In 2020, the IOC released a consensus statement that provides overall guidelines for the recording and reporting of epidemiological data on injury and illness in sport. Some aspects of this statement need to be further specified on a sport-by-sport basis. To extend the IOC consensus statement on methods for recording and reporting of epidemiological data on injury and illness in sports and to meet the sport-specific requirements of all cycling disciplines regulated by the Union Cycliste Internationale (UCI). A panel of 20 experts, all with experience in cycling or cycling medicine, participated in the drafting of this cycling-specific extension of the IOC consensus statement. In preparation, panel members were sent the IOC consensus statement, the first draft of this manuscript and a list of topics to be discussed. The expert panel met in July 2020 for a 1-day video conference to discuss the manuscript and specific topics. The final manuscript was developed in an iterative process involving all panel members. This paper extends the IOC consensus statement to provide cycling-specific recommendations on health problem definitions, mode of onset, injury mechanisms and circumstances, diagnosis classifications, exposure, study population characteristics and data collection methods. Recommendations apply to all UCI cycling disciplines, for both able-bodied cyclists and para-cyclists. The recommendations presented in this consensus statement will improve the consistency and accuracy of future epidemiological studies of injury and illness in cycling.