MAP2 caps tau fibrils and inhibits aggregation.

Fibrils of the microtubule-associated protein tau are intimately linked to the pathology of Alzheimer's disease (AD) and related neurodegenerative disorders. A current paradigm for pathology spreading in the human brain is that short tau fibrils transfer between neurons and then recruit naive tau monomers onto their tips, perpetuating the fibrillar conformation with high fidelity and speed. Although it is known that the propagation could be modulated in a cell-specific manner and thereby contribute to phenotypic diversity, there is still limited understanding of how select molecules are involved in this process. MAP2 is a neuronal protein that shares significant sequence homology with the repeat-bearing amyloid core region of tau. There is discrepancy about MAP2's involvement in pathology and its relationship with tau fibrillization. Here, we employed the entire repeat regions of 3R and 4R MAP2, to investigate their modulatory role in tau fibrillization. We find that both proteins block the spontaneous and seeded aggregation of 4R tau, with 4R MAP2 being slightly more potent. The inhibition of tau seeding is observed in vitro, in HEK293 cells, and in AD brain extracts, underscoring its broader scope. MAP2 monomers specifically bind to the end of tau fibrils, preventing recruitment of further tau and MAP2 monomers onto the fibril tip. The findings uncover a new function for MAP2 as a tau fibril cap that could play a significant role in modulating tau propagation in disease and may hold promise as a potential intrinsic protein inhibitor.

Improving vaccination rates in older adults and at-risk groups: focus on pertussis.

Despite the implementation of effective paediatric vaccination programmes, pertussis remains a global health problem. Disease epidemiology has changed over time, shifting towards the adolescent and adult populations. In adults, the true burden of pertussis is greatly underestimated and pertussis vaccine coverage rates are suboptimal, including individuals with chronic conditions. Here, we report the outcomes of a virtual international scientific workshop to assess the evidence on the burden of pertussis in older adults and identify potential solutions to improve uptake of pertussis vaccines. In adults, pertussis is underdiagnosed in part due to atypical or milder clinical presentation and the lack of testing and case confirmation. However, contemporary epidemiological data denoted an increase in the burden of pertussis among adolescents and adults. This might be related to a variety of reasons including the waning of immunity over time, the lack of booster vaccination, and the improved diagnostic methods that led to increased recognition of the disease in adults. Pertussis sequelae can be severe in older adults, particularly those with existing chronic medical conditions, and the vulnerability of these groups is further enhanced by low pertussis vaccine coverage. Possible measures to increase vaccine uptake include strengthening and harmonisation of immunisation guidelines, healthcare professionals taking a more active role in recommending pertussis vaccination, involvement of vaccination centres and pharmacies in the vaccination process, and improving knowledge of pertussis burden and vaccine efficacy among the general population.

Mechanism for autoinhibition and activation of the MORC3 ATPase.

Microrchidia 3 (MORC3) is a human protein linked to autoimmune disorders, Down syndrome, and cancer. It is a member of a newly identified family of human ATPases with an uncharacterized mechanism of action. Here, we elucidate the molecular basis for inhibition and activation of MORC3. The crystal structure of the MORC3 region encompassing the ATPase and CW domains in complex with a nonhydrolyzable ATP analog demonstrates that the two domains are directly coupled. The extensive ATPase:CW interface stabilizes the protein fold but inhibits the catalytic activity of MORC3. Enzymatic, NMR, mutational, and biochemical analyses show that in the autoinhibited, off state, the CW domain sterically impedes binding of the ATPase domain to DNA, which in turn is required for the catalytic activity. MORC3 autoinhibition is released by disrupting the intramolecular ATPase:CW coupling through the competitive interaction of CW with histone H3 tail or by mutating the interfacial residues. Binding of CW to H3 leads to a marked rearrangement in the ATPase-CW cassette, which frees the DNA-binding site in active MORC3 (on state). We show that ATP-induced dimerization of the ATPase domain is strictly required for the catalytic activity and that the dimeric form of ATPase-CW might cooperatively bind to dsDNA. Together, our findings uncovered a mechanism underlying the fine-tuned regulation of the catalytic domain of MORC3 by the epigenetic reader, CW.

Time-resolved multirotational dynamics of single solution-phase tau proteins reveals details of conformational variation.

Intrinsically disordered proteins (IDPs) are crucial to many cellular processes and have been linked to neurodegenerative diseases. Single molecules of tau, an IDP associated with Alzheimer's disease, are trapped in solution using a microfluidic device, and a time-resolved fluorescence anisotropy decay is recorded for each molecule. Multiple rotational components are resolved and a novel k-means algorithm is used to sort the molecules into two families of conformations. Differences in rotational dynamics suggest a change in the rigidity and steric hindrance surrounding a sequence (306VQIVYK311) which is central to paired helical filament formation. This single-molecule approach can be applied to other IDPs to resolve heterogeneous populations and underlying differences in conformational dynamics.

Live-Cell Super-resolution Reveals F-Actin and Plasma Membrane Dynamics at the T Cell Synapse.

The cortical actin cytoskeleton has been shown to be critical for the reorganization and heterogeneity of plasma membrane components of many cells, including T cells. Building on previous studies at the T cell immunological synapse, we quantitatively assess the structure and dynamics of this meshwork using live-cell superresolution fluorescence microscopy and spatio-temporal image correlation spectroscopy. We show for the first time, to our knowledge, that not only does the dense actin cortex flow in a retrograde fashion toward the synapse center, but the plasma membrane itself shows similar behavior. Furthermore, using two-color, live-cell superresolution cross-correlation spectroscopy, we demonstrate that the two flows are correlated and, in addition, we show that coupling may extend to the outer leaflet of the plasma membrane by examining the flow of GPI-anchored proteins. Finally, we demonstrate that the actin flow is correlated with a third component, α-actinin, which upon CRISPR knockout led to reduced plasma membrane flow directionality despite increased actin flow velocity. We hypothesize that this apparent cytoskeletal-membrane coupling could provide a mechanism for driving the observed retrograde flow of signaling molecules such as the TCR, Lck, ZAP70, LAT, and SLP76.

Fracture and Growth Are Competing Forces Determining the Fate of Conformers in Tau Fibril Populations.

Tau fibrils are pathological aggregates that can transfer between neurons and then recruit soluble Tau monomers by template-assisted conversion. The propagation of different fibril polymorphs is thought to be a contributing factor to phenotypic diversity in Alzheimer disease and other Tauopathies. We found that a homogeneous population of Tau fibrils composed of the truncated version K18 (residues 244-372) gradually converted to a new set of fibril conformers when subjected to multiple cycles of seeding and growth. Using double electron-electron resonance (DEER) spectroscopy, we observed that the distances between spin labels at positions 311 and 328 in the fibril core progressively decreased. The findings were corroborated by changes in turbidity, morphology, and protease sensitivity. Fibrils that were initially formed under stirring conditions exhibited an increased fragility compared with fibrils formed quiescently after multiple cycles of seeding. The quiescently formed fibrils were marked by accelerated growth. The difference in fragility and growth between the different conformers explains how the change in incubation condition could lead to the amplification of a minor subpopulation of fibrils. Under quiescent conditions where fibril breakage is minimal, faster growing fibrils have a selective advantage. The findings are of general importance as they suggest that changes in selective pressures during fibril propagation in the human brain could result in the emergence of new fibril conformers with varied clinicopathological consequences.

Revealing Conformational Variants of Solution-Phase Intrinsically Disordered Tau Protein at the Single-Molecule Level.

Intrinsically disordered proteins, such as tau protein, adopt a variety of conformations in solution, complicating solution-phase structural studies. We employed an anti-Brownian electrokinetic (ABEL) trap to prolong measurements of single tau proteins in solution. Once trapped, we recorded the fluorescence anisotropy to investigate the diversity of conformations sampled by the single molecules. A distribution of anisotropy values obtained from trapped tau protein is conspicuously bimodal while those obtained by trapping a globular protein or individual fluorophores are not. Time-resolved fluorescence anisotropy measurements were used to provide an explanation of the bimodal distribution as originating from a shift in the compaction of the two different families of conformations.

RNA Binds to Tau Fibrils and Sustains Template-Assisted Growth.

Tau fibrils are the main proteinacious components of neurofibrillary lesions in Alzheimer disease. Although RNA molecules are sequestered into these lesions, their relationship to Tau fibrils is only poorly understood. Such understanding, however, is important, as short fibrils can transfer between neurons and nonproteinacious factors including RNA could play a defining role in modulating the latter process. Here, we used sedimentation assays combined with electron paramagnetic resonance (EPR), fluorescence, and absorbance spectroscopy to determine the effects of RNA on Tau fibril structure and growth. We observe that, in the presence of RNA, three-repeat (3R) and four-repeat (4R) Tau form fibrils with parallel, in-register arrangement of ß-strands and exhibit an asymmetric seeding barrier in which 4R Tau grows onto 3R Tau seeds but not vice versa. These structural features are similar to those previously observed for heparin-induced fibrils, indicating that basic conformational properties are conserved, despite their being molecular differences of the nucleating agents. Furthermore, RNA sustains template-assisted growth and binds to the fibril surface and can be exchanged by heparin. These findings suggest that, in addition to mediating fibrillization, cofactors decorating the surface of Tau fibrils may modulate biological interactions and thereby influence the spreading of Tau pathology in the human brain.

Does angioedema in patients with chronic spontaneous urticaria impact response to omalizumab?

The presence of angioedema, or deep skin swelling, in addition to hives (wheals) in patients with chronic spontaneous urticaria (CSU) can complicate disease management. There is evidence that omalizumab is effective for patients with CSU with angioedema, but the time to a clinically meaningful response has not been assessed. This post hoc analysis examined data from the phase 3, randomized, double-blind ASTERIA I and ASTERIA II studies: patients with CSU with hives were grouped by presence (n = 216) or absence of angioedema (n = 265) at baseline. The time to minimally important difference (MID, change from baseline of ≥11 points) in weekly Urticaria Activity Score (UAS7) was analyzed using Kaplan-Meier analyses. Median time to MID for omalizumab 300 mg was similar in patients with and without angioedema. Median time to MID for omalizumab 150 mg was similar to 300 mg for patients without angioedema, and was longer for patients with angioedema. Therefore, the response to omalizumab for patients with CSU with angioedema was dose dependent. We recommend that the best approach for clinicians, in line with guidelines, would be initial administration of omalizumab 300 mg every 4 weeks for all patients. Clinical trials registration: Clinicaltrials.gov NCT01287117 (registered 27 January 2011) and NCT01292473 (registered 7 February 2011).

Real-world outcomes in patients with chronic spontaneous urticaria receiving omalizumab: insights from a clinical practice survey.

OBJECTIVE: Chronic spontaneous urticaria (CSU) is a debilitating inflammatory skin condition, often impacting quality of life. International guidelines recommend omalizumab, an anti-immunoglobulin E antibody, for second-line treatment. Our objective was to understand patient characteristics associated with prescription of omalizumab, and assess real-world outcomes in patients with CSU treated with omalizumab. METHODS: We analyzed data from the Adelphi Real World CSU Disease Specific Programme, a cross-sectional survey with retrospective data collection (December 2020-October 2021) from physicians and patients with CSU in the United States. RESULTS: Data from allergists (n = 45), dermatologists (n = 51), and primary care physicians (PCPs; n = 20) were included. At the time of data collection, one-third of patients were receiving omalizumab (n = 220) and 67% were eligible for but not receiving omalizumab (n = 455). Using logistic regression, the odds of receiving omalizumab were higher in patients whose entire bodies were affected by hives [odds ratio (OR) = 2.551; 95% confidence interval (CI) 1.502-4.333; p < 0.001] or with deteriorating/unstable prognoses at treatment initiation [OR = 2.219; 95% CI 1.031-4.777; p = 0.042], and lower in patients managed by PCPs [OR = 0.276; 95% CI 0.130-0.584; p < 0.001]. Estimates from an inverse probability weighted regression adjustment model indicated that patients receiving omalizumab had higher treatment satisfaction, improvements in itching, hives, angioedema, insomnia, and anxiety, and lower impact on work productivity, compared with patients not receiving omalizumab. CONCLUSION: Around two-thirds of patients with CSU considered eligible for omalizumab were not receiving the guideline-recommended therapy. Patients receiving omalizumab had better real-world outcomes compared with patients not receiving omalizumab. Ensuring patients receive the most appropriate treatment could benefit patients with CSU.

People with a skin rash known as chronic spontaneous urticaria (also called long-lasting hives) have itchy spots that last longer than 6 weeks. People with long-lasting hives may be treated with a medicine called omalizumab to help their itching. We asked doctors why they gave some people omalizumab. We found that only one out of every three people with long-lasting hives were given omalizumab. Doctors gave some people omalizumab because they had long-lasting hives on their whole body or their hives were getting worse. Other people received omalizumab because they were seeing a specialist doctor (allergist) instead of a primary care physician (also called a general practitioner). When compared with people who received other medicines, people being treated with omalizumab had reduced itching, less anxiety, and better well-being. These findings could help doctors choose the right medicine for people with long-lasting hives.

Omalizumab for Patients with Chronic Spontaneous Urticaria: A Narrative Review of Current Status.

Chronic spontaneous urticaria (CSU) is a debilitating inflammatory disorder of the skin, characterized by a fluctuating natural history, a complex mechanism of action, and a significant burden on patients, including effect on quality of life, development of psychosocial disorders, and a range of comorbidities. Recent international guidelines recommend a therapeutic approach of first-line treatment with second generation H1-antihistamines and second-line treatment with the biologic omalizumab. Here, the salient aspects of CSU and current status of data for omalizumab for patients with CSU are reviewed, with a focus on mechanism of action, efficacy and real-world effectiveness (including patient outcomes, response, relapse, and remission), and safety (including consideration of the risk of anaphylaxis). The review also considers recent data on COVID-19, CSU, and omalizumab and presents our perspective on future needs. Overall, the data suggest that omalizumab is an effective and well-tolerated treatment for patients with CSU that provides benefits for a wide range of patients.

Chronic spontaneous urticaria is a skin condition that causes raised red itchy bumps (known as hives) that appear on the skin on most days for 6 weeks or longer. The hives may be big or small, may be warm to touch, may come and go, and may affect a person's quality of life. Omalizumab is a treatment for people living with chronic spontaneous urticaria that can stop the appearance of hives. This article summarizes all the information that we know about omalizumab for chronic spontaneous urticaria, such as how it works, how successful it is at improving hives, how long it takes to work, how it makes patients feel, and how safe it is. The information in this article shows that omalizumab is helpful for many people with chronic spontaneous urticaria.

Selective binding of the PHD6 finger of MLL4 to histone H4K16ac links MLL4 and MOF.

Histone methyltransferase MLL4 is centrally involved in transcriptional regulation and is often mutated in human diseases, including cancer and developmental disorders. MLL4 contains a catalytic SET domain that mono-methylates histone H3K4 and seven PHD fingers of unclear function. Here, we identify the PHD6 finger of MLL4 (MLL4-PHD6) as a selective reader of the epigenetic modification H4K16ac. The solution NMR structure of MLL4-PHD6 in complex with a H4K16ac peptide along with binding and mutational analyses reveal unique mechanistic features underlying recognition of H4K16ac. Genomic studies show that one third of MLL4 chromatin binding sites overlap with H4K16ac-enriched regions in vivo and that MLL4 occupancy in a set of genomic targets depends on the acetyltransferase activity of MOF, a H4K16ac-specific acetyltransferase. The recognition of H4K16ac is conserved in the PHD7 finger of paralogous MLL3. Together, our findings reveal a previously uncharacterized acetyllysine reader and suggest that selective targeting of H4K16ac by MLL4 provides a direct functional link between MLL4, MOF and H4K16 acetylation.

Evaluation of a prompt card for community pharmacists performing consultations with patients on anticoagulation - lessons learned.

OBJECTIVES: To evaluate a prompt card (i.e., a post-card sized tool that lists counselling prompt information) with 5 key elements and 3 open key questions to ask patients in community pharmacies. METHODS: Community pharmacists practicing in England and accredited to perform consultations used the prompt card during a formal consultation with emphasis on patients receiving oral anticoagulation. Main outcome measure was the number of performed consultations with pharmacists' thoughts and feedbacks in writing. RESULTS: During 8 weeks, 19 pharmacists (mean age: 36.6 (SD=9) years; 7 women; accredited an average of 12.9 (SD=9.8) years) performed 1,034 consultations and used the prompt card 104 times during anticoagulation consultations. Overall the prompt card was judged practical and relevant by the 16 pharmacists who used it (100%), especially because it outlines what a good consultation should comprise. The key elements offered a logical framework to guide the overall approach when undertaking a consultation. The two questions, "Why do you want to use this medicine?" and "Why would you not want to use this medicine?" generated negative responses from the patient and pharmacists, respectively. CONCLUSIONS: Our prompt card with key questions summarizing all the points that should be addressed in a consultation supported effective communication during patient-pharmacist interaction. Two questions need rephrasing and a further question is needed to determine how patients are using their medicines.

ZZ-dependent regulation of p62/SQSTM1 in autophagy.

Autophagic receptor p62 is a critical mediator of cell detoxification, stress response, and metabolic programs and is commonly deregulated in human diseases. The diverse functions of p62 arise from its ability to interact with a large set of ligands, such as arginylated (Nt-R) substrates. Here, we describe the structural mechanism for selective recognition of Nt-R by the ZZ domain of p62 (p62ZZ). We show that binding of p62ZZ to Nt-R substrates stimulates p62 aggregation and macroautophagy and is required for autophagic targeting of p62. p62 is essential for mTORC1 activation in response to arginine, but it is not a direct sensor of free arginine in the mTORC1 pathway. We identified a regulatory linker (RL) region in p62 that binds p62ZZ in vitro and may modulate p62 function. Our findings shed new light on the mechanistic and functional significance of the major cytosolic adaptor protein p62 in two fundamental signaling pathways.

Clinical and hemodynamic evaluation of small Perimount aortic valves in patients aged 75 years or older.

BACKGROUND: There is the potential for iatrogenic aortic stenosis and poor quality of life when small aortic valve bioprostheses are used in elderly patients. The alternative is enlarging the aortic annulus to accommodate larger size prostheses, increasing operative mortality. It was hoped that bovine pericardial valves would improve hemodynamic performance in the smaller valve sizes. METHODS: To determine long-term results and in vivo hemodynamic performance of small-size aortic Carpentier-Edwards bovine pericardial valves (Perimount) in elderly patients, we analyzed our follow-up and echocardiographic data from patients 75 years of age or older receiving isolated 19-mm and 21-mm Perimount valves. Ninety-four patients with a mean age of 77 +/- 2.2 years were followed for 12 years. Seventeen patients with 19-mm and 25 patients with 21-mm Perimount valves underwent transthoracic echocardiograms. RESULTS: Operative mortality was 6.3% (6 of 94). Twelve-year survival was 82.7%. Freedom from thromboembolism was 86.9% at 12 years. Two patients had anticoagulation-related bleeding. Overall New York Heart Association class decreased from 3 +/- 1 to 1.6 +/- 0.7 at the end of follow-up. Hemodynamic performances were satisfactory in both 19-mm and 21-mm Perimount valves, with low peak and mean transvalvular gradients and good effective orifice areas, orifice area indices, and performance indices. CONCLUSIONS: Perimount aortic valve in the small aortic annulus has yielded excellent long-term results and hemodynamic performances. Perimount is a very satisfactory option in elderly patients. Implantation of a Perimount bioprosthesis avoids enlargement of the small aortic annulus, reducing mortality and morbidity associated with this procedure.

Ruptura del septum interventricular postinfarto miocardico / Rupture of interventricular septum post-myocardial infarction

Se informan los resultados de la intervencion quirurgica tardia en doce casos de ruptura postinfarto del septum interventricular. En promedio los pacientes fueron intervenidos despues de doce dias de producida la ruptura. Se presentaron dos muertes: una debida a sindrome de bajo gasto cardiaco y otra secundaria un accidente cerebrovascular ppostoperatorio. El manejo inicial se practico con inotropicos, vasodilatadores, diureticos y balon de contrapulsacion intraaortico. E lprocedimiento quirurgico incluyo parche con suturas reforzadas de teflon,aneurismectomia e injertos aortocoronarios cuando fueron necesarios. Se discute la fisiopatologia de la entidad y los resultados obtenidos con intervencion temprana y tardia.