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Pachytene piRNAs are a class of Piwi-interacting small RNAs abundant in spermatids of the adult mouse testis. They are processed from piRNA primary transcripts by a poorly understood mechanism and, unlike fetal transposon-derived piRNAs, lack complementary targets in the spermatid transcriptome. We report that immunopurified complexes of a conserved piRNA pathway protein Maelstrom (MAEL) are enriched in MIWI (Piwi partner of pachytene piRNAs), Tudor-domain proteins and processing intermediates of pachytene piRNA primary transcripts. We provide evidence of functional significance of these complexes in Mael129 knockout mice that exhibit spermiogenic arrest with acrosome and flagellum malformation. Mael129-null mutant testes possess low levels of piRNAs derived from MAEL-associated piRNA precursors and exhibit reduced translation of numerous spermiogenic mRNAs including those encoding acrosome and flagellum proteins. These translation defects in haploid round spermatids are likely indirect, as neither MAEL nor piRNA precursors associate with polyribosomes, and they may arise from an imbalance between pachytene piRNAs and MIWI.

Pachytene pi RNAs are a class of Piwi-interacting small RNAs abundant in spermatids of the adult mouse testis. They are processed from pi RNA primary transcripts by a poorly understood mechanism and, unlike fetal transposon-derived pi RNAs, lack complementary targets in the spermatid transcriptome. We report that immunopurified complexes of a conserved pi RNA pathway protein Maelstrom ( MAEL) are enriched in MIWI (Piwi partner of pachytene piRNAs), Tudor-domain proteins and processing intermediates of pachytene pi RNA primary transcripts. We provide evidence of functional significance of these complexes in Mael 129 knockout mice that exhibit spermiogenic arrest with acrosome and flagellum malformation. Mael 129-null mutant testes possess low levels of pi RNAs derived from MAEL-associated piRNA precursors and exhibit reduced translation of numerous spermiogenic mRNAs including those encoding acrosome and flagellum proteins. These translation defects in haploid round spermatids are likely indirect, as neither MAEL nor pi RNA precursors associate with polyribosomes, and they may arise from an imbalance between pachytene pi RNAs and MIWI. [ABSTRACT FROM AUTHOR]

Introduction We report an Intervention/outcome study of 33 severe COVID-19 subjects who received Seraph100 Microbind Affinity Blood Filter (Seraph 100) hemoperfusion therapy (15 survivors, 18 non-survivors) under emergency authorization from the FDA. Our objective was to determine if Seraph 100 hemoperfusion reduces SARS-CoV-2 RNA titers and/or markers of inflammation and/or epi/endothelial damage.a Methods Viral RNA and 78 protein analytes related to endothelial/epithelial damage and/or inflammation were quantified in systemic blood samples from 33 severe COVID-19 subjects collected upon ICU admission and then immediately before and after blood passed through the heparin-based Seraph 100 filter at two time points on the first day of hemoperfusion. Viral RNA titers were quantified using droplet-digital PCR. Protein analytes were quantified using multiplex/multi-analyte panels on MesoScale Discovery and ProteinSimple-Ella platforms. Results A total of 15/33 subjects had detectable viral RNA in baseline samples (shortly after ICU admission). These initial viremia levels were low, and they did not change uniformly post-perfusion. Five of 55 protein analytes that were up-regulated 1.4-120X at ICU admission relative to healthy controls showed significant decreases across the filter during the indicated time points on the first day of hemoperfusion: IP-10/CXCL10, fms-like tyrosine kinase (Flt-1), MIG/CXCL9, Hepatocyte Growth Factor (HGF) and receptor for advanced glycosylation end-products (RAGE). Paired t-tests identified 25 additional analytes that showed significant decreases (p<0.05) only without Bonferroni correction. Conclusion Initial freely circulating SARS-CoV-2 RNA levels of ICU-admitted subjects were low or undetectable. The Seraph 100 filter did not significantly reduce viral RNA titers in their plasma. However, multiple circulating proteins with roles in inflammation, endothelial/epithelial damage and/or angiogenesis decreased significantly across the filter. Larger prospective trials will be required to determine if such transient reductions translate into improved patient outcomes. However, this study did not demonstrate a direct reduction of free SARS-CoV-2 viral RNA by the Seraph 100., (S. Karger AG, Basel.)