To discover novel genes underlying amyotrophic lateral sclerosis (ALS), we aggregated exomes from 3,864 cases and 7,839 ancestry-matched controls. We observed a significant excess of rare ...protein-truncating variants among ALS cases, and these variants were concentrated in constrained genes. Through gene level analyses, we replicated known ALS genes including SOD1, NEK1 and FUS. We also observed multiple distinct protein-truncating variants in a highly constrained gene, DNAJC7. The signal in DNAJC7 exceeded genome-wide significance, and immunoblotting assays showed depletion of DNAJC7 protein in fibroblasts in a patient with ALS carrying the p.Arg156Ter variant. DNAJC7 encodes a member of the heat-shock protein family, HSP40, which, along with HSP70 proteins, facilitates protein homeostasis, including folding of newly synthesized polypeptides and clearance of degraded proteins. When these processes are not regulated, misfolding and accumulation of aberrant proteins can occur and lead to protein aggregation, which is a pathological hallmark of neurodegeneration. Our results highlight DNAJC7 as a novel gene for ALS.
To determine the outcomes of patients undergoing tracheostomy for COVID-19 and of healthcare workers performing these procedures.
Tracheostomy is often performed for prolonged endotracheal intubation ...in critically ill patients. However, in the context of COVID-19, tracheostomy placement pathways have been altered due to the poor prognosis of intubated patients and the risk of transmission to providers through this highly aerosolizing procedure.
A prospective single-system multi-center observational cohort study was performed on patients who underwent tracheostomy after acute respiratory failure secondary to COVID-19.
Of the 53 patients who underwent tracheostomy, the average time from endotracheal intubation to tracheostomy was 19.7 days ± 6.9 days. The most common indication for tracheostomy was acute respiratory distress syndrome, followed by failure to wean ventilation and post-extracorporeal membrane oxygenation decannulation. Thirty patients (56.6%) were liberated from the ventilator, 16 (30.2%) have been discharged alive, 7 (13.2%) have been decannulated, and 6 (11.3%) died. The average time from tracheostomy to ventilator liberation was 11.8 days ± 6.9 days (range 2-32 days). Both open surgical and percutaneous dilational tracheostomy techniques were performed utilizing methods to mitigate aerosols. No healthcare worker transmissions resulted from performing the procedure.
Alterations to tracheostomy practices and processes were successfully instituted. Following these steps, tracheostomy in COVID-19 intubated patients seems safe for both patients and healthcare workers performing the procedure.
•Measuring pro-inflammatory cytokines may be helpful for the management of COVID-19.•Dynamic cytokine test volume change in our reference lab in response to COVID-19.•It is challenging to interpret ...the multiplex cytokine data for COVID-19 patients.•It is critical to correlate cytokine data with SARS-CoV2 PCR or imaging for COVID.
Coronavirus disease 2019 (COVID-19) is a rapidly evolving infectious/inflammatory disorder which has turned into a global pandemic. With severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as its etiologic agent, severe COVID-19 cases usually develop uncontrolled inflammatory responses and cytokine storm-like syndromes. Measuring serum levels of pro-inflammatory cytokines (e.g., IL-6 and others) as inflammatory biomarkers may have several potential applications in the management of COVID-19, including risk assessment, monitoring of disease progression, determination of prognosis, selection of therapy and prediction of response to treatment.This is especially true for pediatric patients with COVID-19 associated Kawasaki-like disease and similar syndromes. In this report, we review the current knowledge of COVID-19 associated cytokines, their roles in host immune and inflammatory responses, the clinical significance and utility of cytokine immunoassays in adult and pediatric COVID-19 patients, as well as the challenges and pitfalls in implementation and interpretation of cytokine immunoassays. Given that cytokines are implicated in different immunological disorders and diseases, it is challenging to interpret the multiplex cytokine data for COVID-19 patients. Also, it should be taken into consideration that biological and technical variables may affect the commutability of cytokine immunoassays and enhance complexity of cytokine immunoassay interpretation. It is recommended that the same method, platform and laboratory should be used when monitoring differences in cytokine levels between groups of individuals or for the same individual over time. It may be important to correlate cytokine profiling data with the SARS-CoV-2 nucleic acid amplification testing and imaging observations to make an accurate interpretation of the inflammatory status and disease progression in COVID-19 patients.
MicroRNA detection is a valuable method for determining cell identity. Molecular beacons are elegant sensors that can transform intracellular microRNA concentration into a fluorescence intensity. ...While target binding enhances beacon fluorescence, the degree of enhancement is insufficient for demanding applications. The addition of specialty nucleases can enable target recycling and signal amplification, but this process complicates the assay. We have developed and characterized a class of beacons that are susceptible to the endogenous nuclease Argonaute‐2 (Ago2). After purification of the complex by co‐immunoprecipitation, microRNA:Ago2 cleavage (miRACle) beacons undergo site‐ and sequence‐specific cleavage, and show a 13‐fold fluorescence enhancement over traditional beacons. The system can be adapted to any microRNA sequence, and can cleave nuclease‐resistant, non‐RNA bases, potentially allowing miRACle beacons to be designed for cells without interference from non‐specific nucleases.
Simple sensors simulate substrate: MicroRNA detection with molecular beacons can be used for in situ genetic profiling. Beacons that are susceptible to the endogenous nuclease Argonaute‐2 (Ago2) have now been developed. After purification of the complex by co‐immunoprecipitation, microRNA:Ago2 cleavage (miRACle) beacons undergo site‐ and sequence‐specific cleavage, and show a 13‐fold fluorescence enhancement over traditional beacons.
Lymphatic vessels arise chiefly from preexisting embryonic veins. Genetic regulators of lymphatic fate are known, but how dynamic cellular changes contribute during the acquisition of lymphatic ...identity is not understood. We report the visualization of zebrafish lymphatic precursor cell dynamics during fate restriction. In the cardinal vein, cellular commitment is linked with the division of bipotential Prox1-positive precursor cells, which occurs immediately prior to sprouting angiogenesis. Following precursor division, identities are established asymmetrically in daughter cells; one daughter cell becomes lymphatic and progressively upregulates Prox1, and the other downregulates Prox1 and remains in the vein. Vegfc drives cell division and Prox1 expression in lymphatic daughter cells, coupling signaling dynamics with daughter cell fate restriction and precursor division.
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•Prox1 expression initiates in the zebrafish vein before secondary angiogenesis•Prox1 is essential for lymphangiogenesis in zebrafish•Bipotential precursors divide to generate venous and lymphatic endothelial cells•Vegfc concomitantly drives bipotential precursor division and Prox1 expression
Using live imaging, Koltowska and Lagendijk et al. identify bipotential Prox1-expressing precursor cells that divide to generate daughter cells with distinct identities. Following Vegfc-driven cell division, a venous daughter cell remains in the vein and a lymphatic daughter cell leaves, a process by which one vascular lineage derives from another.
ClpXP is an ATP-dependent protease in which the ClpX AAA+ motor binds, unfolds, and translocates specific protein substrates into the degradation chamber of ClpP. We present cryo-EM studies of the
...enzyme that show how asymmetric hexameric rings of ClpX bind symmetric heptameric rings of ClpP and interact with protein substrates. Subunits in the ClpX hexamer assume a spiral conformation and interact with two-residue segments of substrate in the axial channel, as observed for other AAA+ proteases and protein-remodeling machines. Strictly sequential models of ATP hydrolysis and a power stroke that moves two residues of the substrate per translocation step have been inferred from these structural features for other AAA+ unfoldases, but biochemical and single-molecule biophysical studies indicate that ClpXP operates by a probabilistic mechanism in which five to eight residues are translocated for each ATP hydrolyzed. We propose structure-based models that could account for the functional results.
Hematopoietic Cytokines Can Instruct Lineage Choice Rieger, Michael A; Hoppe, Philipp S; Smejkal, Benjamin M ...
Science (American Association for the Advancement of Science),
07/2009, Letnik:
325, Številka:
5937
Journal Article
Recenzirano
The constant regeneration of the blood system during hematopoiesis requires tightly controlled lineage decisions of hematopoietic progenitor cells (HPCs). Because of technical limitations, ...differentiation of individual HPCs could not previously be analyzed continuously. It was therefore disputed whether cell-extrinsic cytokines can instruct HPC lineage choice or only allow survival of cells that are already lineage-restricted. Here, we used bioimaging approaches that allow the continuous long-term observation of individual differentiating mouse HPCs. We demonstrate that the physiological cytokines, macrophage colony-stimulating factor and granulocyte colony-stimulating factor, can instruct hematopoietic lineage choice.
Purpose To test the reliability of the Mayo Elbow Performance Score (MEPS) and compare it with a validated outcomes instrument, the American Shoulder and Elbow Surgeons (ASES) score. Methods A total ...of 42 patients with the chief problem of elbow dysfunction formed the study cohort. Patients with an immediate surgical indication or treatment at the index visit were excluded. The others completed an MEPS questionnaire; at a second visit 2 to 3 weeks later, they completed another MEPS questionnaire and were evaluated with the ASES elbow assessment. Reliability and accuracy were calculated using 2-tailed Pearson correlation coefficients with 95% confidence intervals. Pearson coefficients greater than 0.8 indicated strong agreement. Results The average MEPS score at the initial visit was 58. At the second visit, the average MEPS score was 69 and the average ASES score was 78. The Pearson coefficient for MEPS scores at the 2 time points averaged 0.82, and between the MEPS and ASES scores averaged 0.83. Both coefficients indicated strong agreement. Conclusions The MEPS has strong reliability when assessed at different times and when compared with a validated elbow outcomes instrument. Differences in compared scores of approximately 10 points indicate some patient improvement between time points; however, 95% confidence intervals, standard deviations, and ranges were essentially equivalent between and among tests, indicating similar accuracy. Clinical relevance The MEPS is a reliable outcomes instrument for clinical studies of elbow function that is used to assess nonsurgical treatment.
Zwitterionic polymers are a class of materials that have demonstrated utility as non-fouling surfaces for medical devices and drug delivery vehicles. Here, we develop a synthesis protocol to produce ...zwitterionic polymers as coatings for gold nanoparticles and evaluate nanoparticle stability and biological function after exposure to various biological fluids. Thiol-functionalized polymethacryloyloxyethyl phosphorylcholine polymers (pMPC) were synthesized in nontoxic solvents via photoinitiated free radical polymerization with a radical addition-fragmentation chain transfer (RAFT) agent and coated onto gold nanoparticles. pMPC-coated nanoparticles exhibited reduced particle aggregation, improved suspension stability, and decreased protein adsorption upon exposure to serum and lung lavage fluid (BALF). Cell uptake in A549 cells was greater for pMPC-coated particles than uncoated particles after exposure to serum and BALF, with no observed cell toxicity, but pMPC-coated particles experienced higher levels of cell uptake after serum exposure than BALF exposure, suggesting that differences in the composition of the fluids result in differing impacts on particle fate. These zwitterionic polymers may serve as useful nanoparticle coatings to enhance particle stability and uptake in various biological environments.
Graphical Abstract
The silica-based cell walls of diatoms are prime examples of genetically controlled, species-specific mineral architectures. The physical principles underlying morphogenesis of their hierarchically ...structured silica patterns are not understood, yet such insight could indicate novel routes toward synthesizing functional inorganic materials. Recent advances in imaging nascent diatom silica allow rationalizing possible mechanisms of their pattern formation. Here, we combine theory and experiments on the model diatom
to put forward a minimal model of branched rib patterns-a fundamental feature of the silica cell wall. We quantitatively recapitulate the time course of rib pattern morphogenesis by accounting for silica biochemistry with autocatalytic formation of diffusible silica precursors followed by conversion into solid silica. We propose that silica deposition releases an inhibitor that slows down up-stream precursor conversion, thereby implementing a self-replicating reaction-diffusion system different from a classical Turing mechanism. The proposed mechanism highlights the role of geometrical cues for guided self-organization, rationalizing the instructive role for the single initial pattern seed known as the primary silicification site. The mechanism of branching morphogenesis that we characterize here is possibly generic and may apply also in other biological systems.
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