A conserved ncRNA-binding protein recruits silencing factors to heterochromatin through an RNAi-independent mechanism.

Long noncoding RNAs (lncRNAs) can trigger repressive chromatin, but how they recruit silencing factors remains unclear. In Schizosaccharomyces pombe, heterochromatin assembly on transcribed noncoding pericentromeric repeats requires both RNAi and RNAi-independent mechanisms. In Saccharomyces cerevisiae, which lacks a repressive chromatin mark (H3K9me [methylated Lys9 on histone H3]), unstable ncRNAs are recognized by the RNA-binding protein Nrd1. We show that the S. pombe ortholog Seb1 is associated with pericentromeric lncRNAs. Individual mutation of dcr1+ (Dicer) or seb1+ results in equivalent partial reductions of pericentromeric H3K9me levels, but a double mutation eliminates this mark. Seb1 functions independently of RNAi by recruiting the NuRD (nucleosome remodeling and deacetylase)-related chromatin-modifying complex SHREC (Snf2-HDAC [histone deacetylase] repressor complex).

A conformational switch in HP1 releases auto-inhibition to drive heterochromatin assembly.

A hallmark of histone H3 lysine 9 (H3K9)-methylated heterochromatin, conserved from the fission yeast Schizosaccharomyces pombe to humans, is its ability to spread to adjacent genomic regions. Central to heterochromatin spread is heterochromatin protein 1 (HP1), which recognizes H3K9-methylated chromatin, oligomerizes and forms a versatile platform that participates in diverse nuclear functions, ranging from gene silencing to chromosome segregation. How HP1 proteins assemble on methylated nucleosomal templates and how the HP1-nucleosome complex achieves functional versatility remain poorly understood. Here we show that binding of the key S. pombe HP1 protein, Swi6, to methylated nucleosomes drives a switch from an auto-inhibited state to a spreading-competent state. In the auto-inhibited state, a histone-mimic sequence in one Swi6 monomer blocks methyl-mark recognition by the chromodomain of another monomer. Auto-inhibition is relieved by recognition of two template features, the H3K9 methyl mark and nucleosomal DNA. Cryo-electron-microscopy-based reconstruction of the Swi6-nucleosome complex provides the overall architecture of the spreading-competent state in which two unbound chromodomain sticky ends appear exposed. Disruption of the switch between the auto-inhibited and spreading-competent states disrupts heterochromatin assembly and gene silencing in vivo. These findings are reminiscent of other conditionally activated polymerization processes, such as actin nucleation, and open up a new class of regulatory mechanisms that operate on chromatin in vivo.

Disease severity, treatment patterns, and quality of life in patients with moderate-to-severe psoriasis routinely managed with systemic treatment: results of the CRYSTAL observational study in Central and Eastern European countries.

Psoriasis is a common, life-long skin disease with a significant negative health and societal impact. Data on rates of disease control and treatment strategies are lacking in Central and Eastern European countries. We aimed to describe the real-world disease severity, control, and treatment strategies for psoriasis in patients from Central and Eastern European countries. CRYSTAL (EUPAS36459) was a cross-sectional, retrospective study in adults (18-75 years) from Bulgaria, Estonia, Hungary, Latvia, Lithuania, Romania, and Russia. We enrolled patients with moderate-to-severe psoriasis receiving continuous systemic treatment for ≥24 weeks. We used the Psoriasis Area and Severity Index (PASI) to describe disease severity and the Dermatology Life Quality Index (DLQI) to assess quality of life (QoL) and collected other outcomes [psoriasis work productivity and activity impairment (WPAI-PSO), patient satisfaction] at enrollment. Analyses were descriptive. A total of 690 patients were included in the analyses. Median disease duration was 11.8 years. Current treatment was monotherapy for most patients (95.8%) with either biological (BIO group; 88.4%) or conventional (NON-BIO group; 7.4%) agents. Mean (± standard deviation) absolute PASI scores were 3.5 ± 5.7, 3.1 ± 5.3, and 6.6 ± 7.4 in the overall population, the BIO group, and the NON-BIO group, respectively. Among patients treated with monotherapy, absolute PASI scores ≤1, ≤3, and ≤5 were observed for 44.1%, 72.0%, and 82.6% of BIO patients and 21.6%, 33.3%, and 49.0% of NON-BIO patients. Mean DLQI total score was 3.3 ± 5.1; higher scores were noted for higher absolute PASI. The most impacted WPAI-PSO domain was presenteeism; for all domains, impact increased with increased absolute PASI. A total of 91.8% of BIO patients and 74.5% of NON-BIO patients were satisfied with the current treatment. We observed a better disease control in BIO than NON-BIO patients. However, around half of BIO patients did not reach clear skin status and reported an impact on QoL. An improvement in treatment strategies is still needed in Central and Eastern European countries to optimize outcomes of moderate-to-severe psoriasis.

BioSentinel: Long-Term Saccharomyces cerevisiae Preservation for a Deep Space Biosensor Mission.

The biological risks of the deep space environment must be elucidated to enable a new era of human exploration and scientific discovery beyond low earth orbit (LEO). There is a paucity of deep space biological missions that will inform us of the deleterious biological effects of prolonged exposure to the deep space environment. To safely undertake long-term missions to Mars and space habitation beyond LEO, we must first prove and optimize autonomous biosensors to query the deep space radiation environment. Such biosensors must contain organisms that can survive for extended periods with minimal life support technology and must function reliably with intermittent communication with Earth. NASA's BioSentinel mission, a nanosatellite containing the budding yeast Saccharomyces cerevisiae, is such a biosensor and one of the first biological missions beyond LEO in nearly half a century. It will help fill critical gaps in knowledge about the effects of uniquely composed, chronic, low-flux deep space radiation on biological systems and in particular will provide valuable insight into the DNA damage response to highly ionizing particles. Due to yeast's robustness and desiccation tolerance, it can survive for periods analogous to that of a human Mars mission. In this study, we discuss our optimization of conditions for long-term reagent storage and yeast survival under desiccation in preparation for the BioSentinel mission. We show that long-term yeast cell viability is maximized when cells are air-dried in trehalose solution and stored in a low-relative humidity and low-temperature environment and that dried yeast is sensitive to low doses of deep space-relevant ionizing radiation under these conditions. Our findings will inform the design and development of improved future long-term biological missions into deep space.

BioSentinel: Validating Sensitivity of Yeast Biosensors to Deep Space Relevant Radiation.

With the imminent human exploration of deep space, it is more important than ever to understand the biological risks of deep space radiation exposure. The BioSentinel mission will be the first biological payload to study the effects of radiation beyond low Earth orbit in 50 years. This study is the last in a collection of articles about the BioSentinel biological CubeSat mission, where budding yeast cells will be used to investigate the response of a biological organism to long-term, low-dose deep space radiation. In this study, we define the methodology for detecting the biological response to space-like radiation using simulated deep space radiation and a metabolic indicator dye reduction assay. We show that there is a dose-dependent decrease in yeast cell growth and metabolism in response to space-like radiation, and this effect is significantly more pronounced in a strain of yeast that is deficient in DNA damage repair (rad51Δ) compared with a wild-type strain. Furthermore, we demonstrate the use of flight-like instrumentation after exposure to space-like ionizing radiation. Our findings will inform the development of novel and improved biosensors and technologies for future missions to deep space.

BioSentinel: A Biofluidic Nanosatellite Monitoring Microbial Growth and Activity in Deep Space.

Small satellite technologies, particularly CubeSats, are enabling breakthrough research in space. Over the past 15 years, NASA Ames Research Center has developed and flown half a dozen biological CubeSats in low Earth orbit (LEO) to conduct space biology and astrobiology research investigating the effects of the space environment on microbiological organisms. These studies of the impacts of radiation and reduced gravity on cellular processes include dose-dependent interactions with antimicrobial drugs, measurements of gene expression and signaling, and assessment of radiation damage. BioSentinel, the newest addition to this series, will be the first deep space biological CubeSat, its heliocentric orbit extending far beyond the radiation-shielded environment of low Earth orbit. BioSentinel's 4U biosensing payload, the first living biology space experiment ever conducted beyond the Earth-Moon system, will use a microbial bioassay to assess repair of radiation-induced DNA damage in eukaryotic cells over a duration of 6-12 months. Part of a special collection of articles focused on BioSentinel and its science mission, this article describes the design, development, and testing of the biosensing payload's microfluidics and optical systems, highlighting improvements relative to previous CubeSat life-support and bioanalytical measurement technologies.

The effect of stabilization on the utilization of municipal sewage sludge as a soil amendment.

This study assesses the potential use of different types of stabilized sewage sludge as a soil amendment by considering their physicochemical characteristics, nutritional status, and their trace metal and radionuclide content. The concentrations of trace metals and radionuclides were determined using ICP-OES and gamma-ray spectrometry, respectively. For determining nutritional status and chemical characterization, this study followed standard ISO-recommended procedures. Data analysis revealed that anaerobic sludge contains higher concentrations of Cr, Hg, and Ni compared to aerobic and non-biologically stabilized sludge. A similar observation was observed in the case of 226Ra, 210Pb, 228Ra, and 228Th. Furthermore, the high levels of P and N in aerobic sludge suggest that biologically stabilized sludge has the potential to be a good fertilizer. In addition, the study finds strong evidence that nutrients are involved in the adsorption of metals and radionuclides onto sludge biomass. Overall, eight of the nine studied sludge samples are safe for agricultural use since the concentrations of trace metals fall well below the limits set by Croatian legislation (NN 38/08). In addition, the levels of radionuclides do not pose a radiological risk. This means that soil conditioning with sewage sludge remains a viable strategy for nutrient recovery from municipal waste, although long-term impact assessments of repeated applications are necessary.

Impact of adalimumab on clinical outcomes, healthcare resource utilization, and sick leave in patients with ankylosing spondylitis: an observational study from five Central and Eastern European countries.

BACKGROUND: Patients with ankylosing spondylitis (AS) are substantial users of healthcare resources due to chronic and potentially disabling disease. This study assessed the impact of adalimumab on clinical outcomes, healthcare resource utilization, and sick leave in patients with AS in five Central and Eastern Europe (CEE) countries. METHODS: This was an observational study in the routine clinical setting. Patients diagnosed with AS and starting treatment with originator adalimumab were followed for 12 months by assessing disease activity (Bath Ankylosing Spondylitis Disease Activity Index [BASDAI] and Ankylosing Spondylitis Disease Activity Score [ASDAS]) and physical function (Bath Ankylosing Spondylitis Functional Index [BASFI]). Data on healthcare resource utilization and sick leave were collected prospectively and compared with historical data before adalimumab initiation, as well as between treatment responders and non-responders defined by BASDAI-50. RESULTS: The total effectiveness population comprised 450 patients with on average long-standing AS, high disease activity, and functional impairment. At 12 months of adalimumab therapy, mean ASDAS and BASFI scores were in the range of low disease activity and normal physical function, respectively. The mean number of hospital admissions, hospital inpatient days, and healthcare provider visits were decreased by 67.9, 83.0, and 46.3%, respectively. The number and length of sick leaves were decreased by 65.6 and 81.4%, respectively. Reductions were higher in treatment responders than non-responders. CONCLUSION: Originator adalimumab in routine clinical practice in five CEE countries produced clinically meaningful improvements in disease activity and physical function, and it was associated with reductions in healthcare resource utilization and sick leave.