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Despite its considerable and growing burden, there are currently no Food and Drug Administration‐approved treatments for metabolic dysfunction‐associated steatotic liver disease or its progressive form, metabolic dysfunction‐associated steatohepatitis (MASH). Several glucagon‐like peptide‐1 receptor agonists (GLP‐1RAs) and other agents are in various phases of clinical development for use in MASH; an ideal therapy should reduce liver fat content, improve chronic liver disease, help mitigate metabolic comorbidities and decrease all‐cause mortality. Because of interconnected disease mechanisms, metabolic dysfunction‐associated steatotic liver disease/MASH often coexists with type 2 diabetes (T2D), obesity and cardiovascular disease. Various GLP‐1RAs are Food and Drug Administration‐approved for use in T2D, and two, liraglutide and semaglutide, are approved for overweight and obesity. GLP‐1RAs decrease glucose levels and body weight and improve cardiovascular outcomes in people with T2D who are at high risk of cardiovascular disease. In addition, GLP‐1RAs have been reported to reduce liver fat content and liver enzymes, reduce oxidative stress and improve hepatic de novo lipogenesis and the histopathology of MASH. Weight loss may contribute to these effects; however, the exact mechanisms are unknown. Adverse events that are commonly associated with GLP‐1RAs include vomiting, nausea and diarrhoea. There is a lack of evidence from meta‐analyses regarding the increased risk of acute pancreatitis and various forms of cancer with GLP‐1RAs. Large‐scale, phase 3 trials, which will provide definitive data on GLP‐1RAs and other potential therapies in MASH, are ongoing. Given the spectrum of modalities under investigation, it is hoped that these trials will support the identification of pharmacotherapies that provide clinical benefit for patients with MASH. [ABSTRACT FROM AUTHOR]

Black oat (Avena strigosa Schreb.) might be an attractive forage species in the northeastern United States, since it is generally more heat tolerant and disease resistant than other cool‐season grasses. Black oat is currently recommended for fall and winter production in USDA Plant Hardiness ones 8b–10a, which is beyond the northeastern United States (Zones 2a–6a). The objective was to evaluate 10 black oat breeding lines (referred to as "UF1" through "UF10") for forage accumulation, crude protein (CP), neutral detergent fiber (aNDF), acid detergent fiber (ADF), and in vitro digestible organic matter (IVDOM) concentrations. The experiment was carried out in April–July 2022 in Pennsylvania Furnace, PA. Triticale (× Triticosecale Wittmack cv. TriCal 342) and Legend 567 oat (Avena sativa L.) were included as controls, as well as Haden oat and Gunner triticale, as regionally recommended cultivars. The forage accumulation within the black oat germplasm ranged from 364 to 864 lb dry matter (DM) acre−1, observed in UF7 and UF9, respectively, during the first harvest. During the second harvest, forage accumulation within black oat ranged from 1048 to 1408 lb DM acre−1, from UF8 and UF1, respectively. Crude protein concentrations ranged from 16% to 23% across all black oats, with no differences found within the germplasm. The IVDOM concentrations averaged 78% across all treatments during the first harvest and decreased to 66% during the second harvest. Overall, this study showed that black oat merits further evaluation as forage species in the northeastern United States, but further studies are required to address management of the species. Core Ideas: Black oat is heat tolerant and therefore might be an alternative forage species for the northeastern United States.Further evaluation is required to establish production potential and nutritive value of black oat in the northeastern United States region.Best management practices for black oat are lacking and warranted, especially for future cultivar release. [ABSTRACT FROM AUTHOR]

A non-enveloped virus requires a membrane lesion to deliver its genome into a target cell.sup.1. For rotaviruses, membrane perforation is a principal function of the viral outer-layer protein, VP4.sup.2,3. Here we describe the use of electron cryomicroscopy to determine how VP4 performs this function and show that when activated by cleavage to VP8* and VP5*, VP4 can rearrange on the virion surface from an 'upright' to a 'reversed' conformation. The reversed structure projects a previously buried 'foot' domain outwards into the membrane of the host cell to which the virion has attached. Electron cryotomograms of virus particles entering cells are consistent with this picture. Using a disulfide mutant of VP4, we have also stabilized a probable intermediate in the transition between the two conformations. Our results define molecular mechanisms for the first steps of the penetration of rotaviruses into the membranes of target cells and suggest similarities with mechanisms postulated for other viruses. Electron cryomicroscopy and cryotomography studies reveal that rotaviruses attach to a target cell through the outer-layer protein VP4, which--following cleavage--rearranges to enable perforation of the membrane and delivery of the viral genome into the host cell., Author(s): Tobias Herrmann [sup.1] [sup.2] , Raúl Torres [sup.3] , Eric N. Salgado [sup.3] [sup.7] , Cristina Berciu [sup.4] [sup.8] , Daniel Stoddard [sup.4] [sup.5] , Daniela Nicastro [sup.4] [sup.5] [...]

The prevalence of nonalcoholic fatty liver disease (NAFLD) is increasing worldwide. Nonalcoholic steatohepatitis (NASH) and fibrosis are associated with elevated morbidity and mortality, and a means of differentiating these diseases from simple steatosis (SS) is needed. Liver biopsy in all patients with NAFLD is not feasible, thus necessitating a noninvasive method for discerning the presence of inflammation and fibrosis. Of the various serum markers, cytokeratin-18 seems to best predict NASH, the NAFLD Fibrosis Score is most closely correlated with fibrosis, and transient elastography can be used for diagnosis of cirrhosis, or to exclude cirrhosis, although its utility is limited by obesity.

Access to experimental X-ray diffraction image data is fundamental for validation and reproduction of macromolecular models and indispensable for development of structural biology processing methods. Here, we established a diffraction data publication and dissemination system, Structural Biology Data Grid (SBDG; data.sbgrid.org), to preserve primary experimental data sets that support scientific publications. Data sets are accessible to researchers through a community driven data grid, which facilitates global data access. Our analysis of a pilot collection of crystallographic data sets demonstrates that the information archived by SBDG is sufficient to reprocess data to statistics that meet or exceed the quality of the original published structures. SBDG has extended its services to the entire community and is used to develop support for other types of biomedical data sets. It is anticipated that access to the experimental data sets will enhance the paradigm shift in the community towards a much more dynamic body of continuously improving data analysis.

Mitochondria, chloroplasts and Gram-negative bacteria are encased in a double layer of membranes. The outer membrane contains proteins with a [beta]-barrel structure.sup.1,2. [beta]-Barrels are sheets of [beta]-strands wrapped into a cylinder, in which the first strand is hydrogen-bonded to the final strand. Conserved multi-subunit molecular machines fold and insert these proteins into the outer membrane.sup.3-5. One subunit of the machines is itself a [beta]-barrel protein that has a central role in folding other [beta]-barrels. In Gram-negative bacteria, the [beta]-barrel assembly machine (BAM) consists of the [beta]-barrel protein BamA, and four lipoproteins.sup.5-8. To understand how the BAM complex accelerates folding without using exogenous energy (for example, ATP).sup.9, we trapped folding intermediates on this machine. Here we report the structure of the BAM complex of Escherichia coli folding BamA itself. The BamA catalyst forms an asymmetric hybrid [beta]-barrel with the BamA substrate. The N-terminal edge of the BamA catalyst has an antiparallel hydrogen-bonded interface with the C-terminal edge of the BamA substrate, consistent with previous crosslinking studies.sup.10-12; the other edges of the BamA catalyst and substrate are close to each other, but curl inward and do not pair. Six hydrogen bonds in a membrane environment make the interface between the two proteins very stable. This stability allows folding, but creates a high kinetic barrier to substrate release after folding has finished. Features at each end of the substrate overcome this barrier and promote release by stepwise exchange of hydrogen bonds. This mechanism of substrate-assisted product release explains how the BAM complex can stably associate with the substrate during folding and then turn over rapidly when folding is complete. Cryo-electron microscopy structures of a folding intermediate on the BAM complex of Escherichia coli reveal how interactions between the BamA catalyst and substrate permit stable association during folding, followed by rapid turnover., Author(s): David Tomasek [sup.1] [sup.2] , Shaun Rawson [sup.3] , James Lee [sup.1] [sup.2] [sup.5] , Joseph S. Wzorek [sup.2] [sup.6] , Stephen C. Harrison [sup.3] [sup.4] , Zongli Li [...]

Bruton's tyrosine kinase (Btk), a Tec-family tyrosine kinase, is essential for B-cell function. We present crystallographic and biochemical analyses of Btk, which together reveal molecular details of its autoinhibition and activation. Autoinhibited Btk adopts a compact conformation like that of inactive c-Src and c-Abl. A lipid-binding PH-TH module, unique to Tec kinases, acts in conjunction with the SH2 and SH3 domains to stabilize the inactive conformation. In addition to the expected activation of Btk by membranes containing phosphatidylinositol triphosphate (PIP3), we found that inositol hexakisphosphate (IP6), a soluble signaling molecule found in both animal and plant cells, also activates Btk. This activation is a consequence of a transient PH-TH dimerization induced by IP6, which promotes transphosphorylation of the kinase domains. Sequence comparisons with other Tec-family kinases suggest that activation by IP6 is unique to Btk.

The prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) is increasing worldwide. Primary care providers play a critical role in the screening, diagnosis, and management of MASLD and/or metabolic dysfunction-associated steatohepatitis (MASH), though they can face challenges in this setting, particularly where healthcare resources are limited and barriers to care exist. To address these challenges, several guidelines have been developed to provide evidence-based recommendations for the clinical assessment and management of patients with MASLD/MASH. To provide a unified, simple-to-understand, practical guide for MASLD screening, diagnosis, and management based on current guideline recommendations, for use by primary care providers in daily practice. Evidence-based recommendations from several international guidelines were summarized, focusing on the similarities and differences between them. Recommendations are broadly aligned across the guidelines, but several key differences are evident. Practical guidance is provided on screening, identifying target populations for risk stratification, initial evaluation of individuals with suspected MASLD, surveillance, risk stratification and referral, as well as approaches to the management of MASLD and associated comorbidities, with specific considerations for the primary care setting. Primary care providers are ideally placed to identify at-risk individuals, implement evidence-based interventions to prevent the development of fibrosis and cirrhosis, and effectively manage comorbidities. Equipping primary care providers with the necessary knowledge and tools to effectively manage MASLD/MASH may help to improve patient outcomes and reduce the burden of liver disease. [ABSTRACT FROM AUTHOR]

Rotaviruses infect cells by delivering into the cytosol a transcriptionally active inner capsid particle (a "double-layer particle": DLP). Delivery is the function of a third, outer layer, which drives uptake from the cell surface into small vesicles from which the DLPs escape. In published work, we followed stages of rhesus rotavirus (RRV) entry by live-cell imaging and correlated them with structures from cryogenic electron microscopy and tomography (cryo-EM and cryo-ET). The virus appears to wrap itself in membrane, leading to complete engulfment and loss of Ca2+ from the vesicle produced by the wrapping. One of the outer-layer proteins, VP7, is a Ca2+-stabilized trimer; loss of Ca2+ releases both VP7 and the other outer-layer protein, VP4, from the particle. VP4, activated by cleavage into VP8* and VP5*, is a trimer that undergoes a large-scale conformational rearrangement, reminiscent of the transition that viral fusion proteins undergo to penetrate a membrane. The rearrangement of VP5* thrusts a 250-residue, C-terminal segment of each of the three subunits outward, while allowing the protein to remain attached to the virus particle and to the cell being infected. We proposed that this segment inserts into the membrane of the target cell, enabling Ca2+ to cross. In the work reported here, we show the validity of key aspects of this proposed sequence. By cryo-EM studies of liposome-attached virions ("triple-layer particles": TLPs) and single-particle fluorescence imaging of liposome-attached TLPs, we confirm insertion of the VP4 C-terminal segment into the membrane and ensuing generation of a Ca2+ "leak". The results allow us to formulate a molecular description of early events in entry. We also discuss our observations in the context of other work on double-strand RNA virus entry. Author summary: To infect a cell, non-enveloped viruses must have a mechanism to transfer their genomes across a membrane. The double-strand RNA (dsRNA) viruses deliver into the cytosol not just their genomes but an intact subviral particle (diameter ~70 nm). Rhesus rotavirus (RRV) particles attach through a spike-like outer-layer protein, VP4 (cleaved to VP5* and VP8*), then wrap themselves in membrane at the cell surface, producing a small, cytosolic vesicle surrounding each virion, from which the subviral particles escape directly. Loss of Ca2+ from the entering virion always precedes escape. In previous work we found that a conformational change in VP5*/VP8* projects the C-terminal "foot" domain of VP5* outward. We now show, by combining cryo-EM and single-particle optical microscopy of RRV particles interacting with liposomes, that the outward-projected foot penetrates the lipid bilayer, permeabilizing it to Ca2+. The new experiments thus recapitulate the initial step in particle escape and show that the conformational change must occur while the spike protein is membrane-attached, to couple the VP5* conformational change with membrane insertion. These findings bring us closer to a full molecular description how a large, subviral particle (about 70 nm diameter) can be delivered into a target host cell. [ABSTRACT FROM AUTHOR]