Superficial Temporal Artery-to-Middle Cerebral Artery Bypass in Ischemic Stroke With Blood Pressure-Dependent Symptoms.

The efficacy of extracranial-intracranial (EC-IC) bypass in preventing ischemic stroke progression and recurrence is controversial. As per the current hypothesis, EC-IC bypass is most beneficial for patients with persistent hemodynamic insufficiency. Hence, various approaches have been used to evaluate hemodynamic insufficiency, including repeated single photon emission CT (SPECT) imaging or continuous monitoring of cerebral flow with transcranial Doppler ultrasound (TCD). However, both modalities are time- and resource-intensive. In this report, we discuss how EC-IC bypass turned out to be beneficial for a patient presenting with blood pressure-dependent severe aphasia and right hemiparesis due to middle cerebral artery (MCA) occlusion that failed thrombectomy. CT perfusion (CTP) scan at admission demonstrated a persistent volume of delayed perfusion without core infarct. Following the superficial temporal artery-to-middle cerebral artery (STA-MCA) bypass, the patient's National Institute of Health Stroke Scale (NIHSS) score improved from 12 to 1. Ischemic penumbra, as seen on CTP imaging, also improved after the STA-MCA bypass. Our case suggests that persistent volume of delayed perfusion and blood pressure-dependent neurological deficits can be used in tandem as selection criteria for EC-IC bypass.

LXRα Promotes Abdominal Aortic Aneurysm Formation Through UHRF1 Epigenetic Modification of miR-26b-3p.

BACKGROUND: Abdominal aortic aneurysm (AAA) is a severe aortic disease without effective pharmacological approaches. The nuclear hormone receptor LXRα (liver X receptor α), encoded by the NR1H3 gene, serves as a critical transcriptional mediator linked to several vascular pathologies, but its role in AAA remains elusive. METHODS: Through integrated analyses of human and murine AAA gene expression microarray data sets, we identified NR1H3 as a candidate gene regulating AAA formation. To investigate the role of LXRα in AAA formation, we used global Nr1h3-knockout and vascular smooth muscle cell-specific Nr1h3-knockout mice in 2 AAA mouse models induced with angiotensin II (1000 ng·kg·min; 28 days) or calcium chloride (CaCl2; 0.5 mol/L; 42 days). RESULTS: Upregulated LXRα was observed in the aortas of patients with AAA and in angiotensin II- or CaCl2-treated mice. Global or vascular smooth muscle cell-specific Nr1h3 knockout inhibited AAA formation in 2 mouse models. Loss of LXRα function prevented extracellular matrix degeneration, inflammation, and vascular smooth muscle cell phenotypic switching. Uhrf1, an epigenetic master regulator, was identified as a direct target gene of LXRα by integrated analysis of transcriptome sequencing and chromatin immunoprecipitation sequencing. Susceptibility to AAA development was consistently enhanced by UHRF1 (ubiquitin-like containing PHD and RING finger domains 1) in both angiotensin II- and CaCl2-induced mouse models. We then determined the CpG methylation status and promoter accessibility of UHRF1-mediated genes using CUT&Tag (cleavage under targets and tagmentation), RRBS (reduced representation bisulfite sequencing), and ATAC-seq (assay for transposase-accessible chromatin with sequencing) in vascular smooth muscle cells, which revealed that the recruitment of UHRF1 to the promoter of miR-26b led to DNA hypermethylation accompanied by relatively closed chromatin states, and caused downregulation of miR-26b expression in AAA. Regarding clinical significance, we found that underexpression of miR-26b-3p correlated with high risk in patients with AAA. Maintaining miR-26b-3p expression prevented AAA progression and alleviated the overall pathological process. CONCLUSIONS: Our study reveals a pivotal role of the LXRα/UHRF1/miR-26b-3p axis in AAA and provides potential biomarkers and therapeutic targets for AAA.

Impact of age on the host response to sepsis in a murine model of fecal-induced peritonitis.

INTRODUCTION: Despite older adults being more vulnerable to sepsis, most preclinical research on sepsis has been conducted using young animals. This results in decreased scientific validity since age is an independent predictor of poor outcome. In this study, we explored the impact of aging on the host response to sepsis using the fecal-induced peritonitis (FIP) model developed by the National Preclinical Sepsis Platform (NPSP). METHODS: C57BL/6 mice (3 or 12 months old) were injected intraperitoneally with rat fecal slurry (0.75 mg/g) or a control vehicle. To investigate the early stage of sepsis, mice were culled at 4 h, 8 h, or 12 h to investigate disease severity, immunothrombosis biomarkers, and organ injury. Mice received buprenorphine at 4 h post-FIP. A separate cohort of FIP mice were studied for 72 h (with buprenorphine given at 4 h, 12 h, and then every 12 h post-FIP and antibiotics/fluids starting at 12 h post-FIP). Organs were harvested, plasma levels of Interleukin (IL)-6, IL-10, monocyte chemoattract protein (MCP-1)/CCL2, thrombin-antithrombin (TAT) complexes, cell-free DNA (CFDNA), and ADAMTS13 activity were quantified, and bacterial loads were measured. RESULTS: In the 12 h time course study, aged FIP mice demonstrated increased inflammation and injury to the lungs compared to young FIP mice. In the 72 h study, aged FIP mice exhibited a higher mortality rate (89%) compared to young FIP mice (42%) (p < 0.001). Aged FIP non-survivors also exhibited a trend towards elevated IL-6, TAT, CFDNA, CCL2, and decreased IL-10, and impaired bacterial clearance compared to young FIP non-survivors. CONCLUSION: To our knowledge, this is the first study to investigate the impact of age on survival using the FIP model of sepsis. Our model includes clinically-relevant supportive therapies and inclusion of both sexes. The higher mortality rate in aged mice may reflect increased inflammation and worsened organ injury in the early stage of sepsis. We also observed trends in impaired bacterial clearance, increase in IL-6, TAT, CFDNA, CCL2, and decreased IL-10 and ADAMTS13 activity in aged septic non-survivors compared to young septic non-survivors. Our aging model may help to increase the scientific validity of preclinical research and may be useful for identifying mechanisms of age-related susceptibility to sepsis as well as age-specific treatment strategies.

Endothelial ELABELA improves post-ischemic angiogenesis by upregulating VEGFR2 expression.

BACKGROUND: Post-ischemic angiogenesis is critical for perfusion recovery and tissue repair. ELABELA (ELA) plays an essential role in embryonic heart development and vasculogenesis. However, the mechanism of ELA on post-ischemic angiogenesis is poorly characterized. METHODS: We first assessed ELA expression after hind limb ischemia (HLI) in mice. We then established a HLI model in tamoxifen-inducible endothelial-ELA-specific knockout mice (ELAECKO) and assessed the rate of perfusion recovery, capillary density, and VEGFR2 pathway. Knockdown of ELA with lentivirus or siRNA and exogenous addition of ELA peptides were employed to analyze the effects of ELA on angiogenic capacity and VEGFR2 pathway in endothelial cells in vitro. The serum levels of ELA in healthy people and patients with type 2 diabetes mellitus (T2DM) and diabetic foot ulcer (DFU) were detected by a commercial ELISA kit. RESULTS: In murine HLI models, ELA was significantly up-regulated in the ischemic hindlimb. Endothelial-specific deletion of ELA impaired perfusion recovery and angiogenesis. In physiologic conditions, no significant difference in VEGFR2 expression was found between ELAECKO mice and ELAWT mice. After ischemia, the expression of VEGFR2, p-VEGFR2, and p-AKT was significantly lower in ELAECKO mice than in ELAWT mice. In cellular experiments, the knockdown of ELA inhibited endothelial cell proliferation and tube formation, and the addition of ELA peptides promoted proliferation and tube formation. Mechanistically, ELA upregulated the expression of VEGFR2, p-VEGFR2, and p-AKT in endothelial cells under hypoxic conditions. In clinical investigations, DFU patients had significantly lower serum levels of ELA compared to T2DM patients. CONCLUSION: Our results indicated that endothelial ELA is a positive regulator of post-ischemic angiogenesis via upregulating VEGFR2 expression. Targeting ELA may be a potential therapeutic option for peripheral arterial diseases.

Motor neurons generate pose-targeted movements via proprioceptive sculpting.

Motor neurons are the final common pathway1 through which the brain controls movement of the body, forming the basic elements from which all movement is composed. Yet how a single motor neuron contributes to control during natural movement remains unclear. Here we anatomically and functionally characterize the individual roles of the motor neurons that control head movement in the fly, Drosophila melanogaster. Counterintuitively, we find that activity in a single motor neuron rotates the head in different directions, depending on the starting posture of the head, such that the head converges towards a pose determined by the identity of the stimulated motor neuron. A feedback model predicts that this convergent behaviour results from motor neuron drive interacting with proprioceptive feedback. We identify and genetically2 suppress a single class of proprioceptive neuron3 that changes the motor neuron-induced convergence as predicted by the feedback model. These data suggest a framework for how the brain controls movements: instead of directly generating movement in a given direction by activating a fixed set of motor neurons, the brain controls movements by adding bias to a continuing proprioceptive-motor loop.

Evaluation of the Factors Affecting Higher Hospitalization Cost of Lung Resection for Primary Lung Cancer: A Retrospective Cohort Study.

PURPOSE: This study aims to evaluate the factors associated with the higher hospitalization cost of lung resection for primary lung cancer to contribute to the reduction of healthcare spending. METHODS: A total of 435 consecutive primary lung cancer patients who underwent lung resection by a single surgeon at a single institution were enrolled. Baseline patient characteristics, operative procedures, postoperative complications, and postoperative courses were analyzed in relation to the hospitalization cost. Patients with higher costs (exceeding the third quartile [TQ]) were compared with patients with lower costs (less than TQ). RESULTS: Median and TQ medical costs for overall cases were 11177 US dollars (USD) and 12292 USD, respectively. Smoking history, history of coronary artery disease, previous thoracotomy, multiple sealant material use, transfusion, tumor factor T3 or higher, squamous cell carcinoma, postoperative complications, and longer postoperative hospital stay (>10 POD) were significant risk factors for increased hospitalization cost in multivariate analysis. The 5-year survival rate was significantly lower in the higher hospitalization cost group. CONCLUSION: In addition to postoperative complications and prolonged hospitalization, patient background, histological types, and intraoperative factors were also considered as the risk factors for higher medical costs.

A Bayesian finite mixture model approach to evaluate dichotomization method for correlated ELISA tests.

In diagnostic accuracy studies, a commonly employed approach involves dichotomizing continuous data and subsequently analyzing them using a Bayesian latent class model (BLCM), often relying on binomial or multinomial distributions, rather than preserving their continuous nature. However, this procedure can inadvertently lead to less reliable outcomes due to the inherent loss of information when converting the original continuous measurements into binary values. Through comprehensive simulations, we demonstrated the limitations and disadvantages of dichotomizing continuous biomarkers from two correlated tests. Our findings highlighted notable disparities between the true values and the model estimates as a result of dichotomization. We discovered the crucial significance of selecting a reference test with high diagnostic accuracy in test evaluation in order to obtain reliable estimates of test accuracy and prevalences. Our study served as a call to action for veterinary researchers to exercise caution when utilizing dichotomization.

Assessment of Advanced Diagnostic Bronchoscopy Outcomes for Peripheral Lung Lesions: A Delphi Consensus Definition of Diagnostic Yield and Recommendations for Patient-centered Study Designs. An Official American Thoracic Society/American College of Chest Physicians Research Statement.

Background: Advanced diagnostic bronchoscopy targeting the lung periphery has developed at an accelerated pace over the last two decades, whereas evidence to support introduction of innovative technologies has been variable and deficient. A major gap relates to variable reporting of diagnostic yield, in addition to limited comparative studies. Objectives: To develop a research framework to standardize the evaluation of advanced diagnostic bronchoscopy techniques for peripheral lung lesions. Specifically, we aimed for consensus on a robust definition of diagnostic yield, and we propose potential study designs at various stages of technology development. Methods: Panel members were selected for their diverse expertise. Workgroup meetings were conducted in virtual or hybrid format. The cochairs subsequently developed summary statements, with voting proceeding according to a modified Delphi process. The statement was cosponsored by the American Thoracic Society and the American College of Chest Physicians. Results: Consensus was reached on 15 statements on the definition of diagnostic outcomes and study designs. A strict definition of diagnostic yield should be used, and studies should be reported according to the STARD (Standards for Reporting Diagnostic Accuracy Studies) guidelines. Clinical or radiographic follow-up may be incorporated into the reference standard definition but should not be used to calculate diagnostic yield from the procedural encounter. Methodologically robust comparative studies, with incorporation of patient-reported outcomes, are needed to adequately assess and validate minimally invasive diagnostic technologies targeting the lung periphery. Conclusions: This American Thoracic Society/American College of Chest Physicians statement aims to provide a research framework that allows greater standardization of device validation efforts through clearly defined diagnostic outcomes and robust study designs. High-quality studies, both industry and publicly funded, can support subsequent health economic analyses and guide implementation decisions in various healthcare settings.

Sodium dichloroacetate improves migration ability by suppressing LPS-induced inflammation in HTR-8/SVneo cells via the TLR4/NF-κB pathway.

Objectives: Inadequate cytotrophoblast migration and invasion are speculated to result in preeclampsia, which is a pro-inflammatory condition. Sodium dichloroacetate (DCA) exerts anti-inflammatory actions. Thus,we sought to investigate the effect of DCA on the migration function of the lipopolysaccharide (LPS)-stimulated human-trophoblast-derived cell line (HTR-8/SVneo). Materials and Methods: HTR-8/SVneo cells were treated with LPS to suppress cell migration. Cell migration was examined by both scratch wound healing assay and transwell migration assay. Western blotting was used to analyze the expression levels of toll-like receptor-4 (TLR4), nuclear factor-κB (NF-κB), TNF-α, IL-1ß, and IL-6 in the cells. Results: DCA reversed LPS-induced inhibition of migration in HTR-8/SVneo cells. Furthermore, DCA significantly suppressed LPS-induced activation of TLR4, phosphorylation of NF-κB (p65), translocation of p65 into the nucleus, and the production of pro-inflammatory cytokines (TNF-α, IL-1ß, and IL-6). Treatment with inhibitors of TLR4 signal transduction (CLI095 or MD2-TLR-4-IN-1) reduced LPS-induced overexpression of pro-inflammatory cytokines, and a synergistic effect was found between TLR4 inhibitors and DCA in HTR-8/SVneo cells. Conclusion: DCA improved trophoblast cell migration function by suppressing LPS-induced inflammation, at least in part, via the TLR4/NF-κB signaling pathway. This result indicates that DCA might be a potential therapeutic candidate for human pregnancy-related complications associated with trophoblast disorder.

PD1+TIGIT+2B4+KLRG1+ Cells Might Underlie T Cell Dysfunction in Patients Treated with BCMA-Directed Chimeric Antigen Receptor T Cell Therapy.

Chimeric antigen receptor T cell (CAR-T) therapy has shown rapid, frequent, and deep responses in patients with relapsed/refractory multiple myeloma (RRMM). However, relapse frequently occurs following CAR-T therapy, and the cause of this resistance is not well defined. Among the potential mechanisms of resistance, T cell intrinsic factors may be an important source of failure. Here we used spectral flow cytometry to identify the changes in T cell phenotypes in bone marrow aspirates at different stages of multiple myeloma progression, including cases that relapsed after anti-BCMA CAR-T therapy. We identified completely different T cell phenotypes in RRMM and post CAR-T relapse cases compared to healthy donors and earlier stages of multiple myeloma, novel double-negative CD3+ T cells in RRMM and CAR-T relapsed cases, and differences in CD8 T cell phenotype at the baseline between peripheral blood and bone marrow from healthy donors. We found that the majority of T cells in RRMM patients and significant T cell subsets in post-CAR-T relapsed patients expressed multiple coinhibitory markers, including PD1, TIGIT, 2B4, and KLRG1.

O-GlcNAc modification of GSDMD attenuates LPS-induced endothelial cells pyroptosis.

OBJECTIVE: Increased O-linked ß-N-acetylglucosamine (O-GlcNAc) stimulation has been reported to protect against sepsis associated mortality and cardiovascular derangement. Previous studies, including our own research, have indicated that gasdermin-D(GSDMD)-mediated endothelial cells pyroptosis contributes to sepsis-associated endothelial injury. This study explored the functions and mechanisms of O-GlcNAc modification on lipopolysaccharide (LPS)-induced pyroptosis and its effects on the function of GSDMD. METHODS: A LPS-induced septic mouse model administrated with O-GlcNAcase (OGA) inhibitor thiamet-G (TMG) was used to assess the effects of O-GlcNAcylation on sepsis-associated vascular dysfunction and pyroptosis. We conducted experiments on human umbilical vein endothelial cells (HUVECs) by challenging them with LPS and TMG to investigate the impact of O-GlcNAcylation on endothelial cell pyroptosis and implications of GSDMD. Additionally, we identified potential O-GlcNAcylation sites in GSDMD by utilizing four public O-GlcNAcylation site prediction database, and these sites were ultimately established through gene mutation. RESULTS: Septic mice with increased O-GlcNAc stimulation exhibited reduced endothelial injury, GSDMD cleavage (a marker of pyroptosis). O-GlcNAc modification of GSDMD mitigates LPS-induced pyroptosis in endothelial cells by preventing its interaction with caspase-11 (a human homologous of caspases-4/5). We also identified GSDMD Serine 338 (S338) as a novel site of O-GlcNAc modification, leading to decreased association with caspases-4 in HEK293T cells. CONCLUSIONS: Our findings identified a novel post-translational modification of GSDMD and elucidated the O-GlcNAcylation of GSDMD inhibits LPS-induced endothelial injury, suggesting that O-GlcNAc modification-based treatments could serve as potential interventions for sepsis-associated vascular endothelial injury.

Clinical outcomes of endoscopic submucosal dissection for superficial esophageal neoplasia in close proximity to esophageal varices: a multicenter international experience.

BACKGROUND : There are limited data on the feasibility of endoscopic submucosal dissection (ESD) for superficial esophageal neoplasia (SEN) located at or adjacent to esophageal varices. We aimed to evaluate the outcomes of ESD in these patients. METHODS: This multicenter retrospective study included cirrhotic patients with a history of esophageal varices with SEN located at or adjacent to the esophageal varices who underwent ESD. RESULTS: 23 patients with SEN (median lesion size 30 mm; 16 squamous cell neoplasia and seven Barrett's esophagus-related neoplasia) were included. The majority were Child-Pugh B (57 %) and had small esophageal varices (87 %). En bloc, R0, and curative resections were achieved in 22 (96 %), 21 (91 %), and 19 (83 %) of patients, respectively. Severe intraprocedural bleeding (n = 1) and delayed bleeding (n = 1) were successfully treated endoscopically. No delayed perforation, hepatic decompensation, or deaths were observed. During a median (interquartile range) follow-up of 36 (22-55) months, one case of local recurrence occurred after noncurative resection. CONCLUSION: ESD is feasible and effective for SEN located at or adjacent to esophageal varices in cirrhotic patients. Albeit, the majority of the esophageal varices in our study were small in size, when expertise is available, ESD should be considered as a viable option for such patients.

Functions, Mechanisms, and therapeutic applications of the inositol pyrophosphates 5PP-InsP5 and InsP8 in mammalian cells.

Water-soluble myo-inositol phosphates have long been characterized as second messengers. The signaling properties of these compounds are determined by the number and arrangement of phosphate groups on the myo-inositol backbone. Recently, higher inositol phosphates with pyrophosphate groups were recognized as signaling molecules. 5-Diphosphoinositol 1,2,3,4,6-pentakisphosphate (5PP-InsP5) is the most abundant isoform, constituting more than 90% of intracellular inositol pyrophosphates. 5PP-InsP5 can be further phosphorylated to 1,5-bisdiphosphoinositol 2,3,4,6-tetrakisphosphate (InsP8). These two molecules, 5PP-InsP5 and InsP8, are present in various subcellular compartments, where they participate in regulating diverse cellular processes such as cell death, energy homeostasis, and cytoskeletal dynamics. The synthesis and metabolism of inositol pyrophosphates are subjected to tight regulation, allowing for their highly specific functions. Blocking the 5PP-InsP5/InsP8 signaling pathway by inhibiting the biosynthesis of 5PP-InsP5 demonstrates therapeutic benefits in preclinical studies, and thus holds promise as a therapeutic approach for certain diseases treatment, such as metabolic disorders.

Aging-Associated ALKBH5-m6A Modification Exacerbates Doxorubicin-Induced Cardiomyocyte Apoptosis Via AT-Rich Interaction Domain 2.

BACKGROUND: Chemotherapy-induced cardiovascular disease is a growing concern in the elderly population who have survived cancer, yet the underlying mechanism remains poorly understood. We investigated the role of ALKBH5 (AlkB homolog 5), a primary N6-methyladenosine (m6A) demethylase, and its involvement in m6A methylation-mediated regulation of targets in aging-associated doxorubicin-induced cardiotoxicity. METHODS AND RESULTS: To validate the relationship between doxorubicin-induced cardiotoxicity and aging, we established young and old male mouse models. ALKBH5 expression was modulated through adeno-associated virus 9 (in vivo), Lentivirus, and siRNAs (in vitro) to examine its impact on cardiomyocyte m6A modification, doxorubicin-induced cardiac dysfunction, and remodeling. We performed mRNA sequencing, methylated RNA immunoprecipitation sequencing, and molecular assays to unravel the mechanism of ALKBH5-m6A modification in doxorubicin-induced cardiotoxicity. Our data revealed an age-dependent increase in doxorubicin-induced cardiac dysfunction, remodeling, and injury. ALKBH5 expression was elevated in aging mouse hearts, leading to reduced global m6A modification levels. Through mRNA sequencing and methylated RNA immunoprecipitation sequencing analyses, we identified ARID2 (AT-rich interaction domain 2) as the downstream effector of ALKBH5-m6A modulation in cardiomyocytes. Further investigations revealed that ARID2 modulates DNA damage response and enhances doxorubicin-induced cardiomyocyte apoptosis. CONCLUSIONS: Our findings provide insights into the role of ALKBH5-m6A modification in modulating doxorubicin-induced cardiac dysfunction, remodeling, and cardiomyocyte apoptosis in male mice. These results highlight the potential of ALKBH5-targeted treatments for elderly patients with cancer in clinical settings.

Seeing stars: Astroglia modulate visual circuits during behavioral-state transitions.

In this issue of Neuron, Uribe-Arias et al.1 show that, in larval zebrafish, astrocyte-like cells exhibit calcium responses to norepinephrine during behavioral-state transitions and alter neuronal response properties. Thus, astroglia can sculpt neuronal dynamics in behaviorally meaningful ways.

Surface immobilized α-1 acid glycoprotein and collagen VI modulate mouse macrophage polarization and reduce the foreign body capsule.

Macrophages are widely recognized in modulating the foreign body response, and the manner in which they do so largely depends on their activation state, often referred to as their polarization. This preliminary study demonstrates that surface immobilized α-1 acid glycoprotein (AGP), as well as collagen VI (Col6) in conjunction with AGP, can direct macrophages towards the M2 polarization state in vitro and modify the foreign body response in vivo. AGP and Col6 are immobilized onto poly(2-hydroxyethyl methacrylate) (pHEMA) surfaces using carbonyl diimidazole chemistry. Mouse bone marrow derived macrophages are cultured on modified surfaces with or without lipopolysaccharide stimulation. Surface modified pHEMA discs are implanted subcutaneously into mice to observe differences in the foreign body response. After stimulation with lipopolysaccharide, macrophages cultured on AGP or Col6 modified surfaces showed a reduction in TNF-α expression compared to controls. Arg1 expression was also increased in macrophages cultured on modified surfaces. Explanted tissues showed that the foreign body capsule around implants with AGP or AGP and Col6 modification had reduced thickness, while also being more highly vascularized. These data demonstrate that α-1 acid glycoprotein and collagen VI could potentially be used for the surface modification of medical devices to influence macrophage polarization leading to a reduced and modulated foreign body response.

Division of labor among H3K4 Methyltransferases Defines Distinct Facets of Homeostatic Plasticity.

Heterozygous mutations in any of the six H3K4 methyltransferases (KMT2s) result in monogenic neurodevelopmental disorders, indicating nonredundant yet poorly understood roles of this enzyme family in neurodevelopment. Recent evidence suggests that histone methyltransferase activity may not be central to KMT2 functions; however, the enzymatic activity is evolutionarily conserved, implicating the presence of selective pressure to maintain the catalytic activity. Here, we show that H3K4 methylation is dynamically regulated during prolonged alteration of neuronal activity. The perturbation of H3K4me by the H3.3K4M mutant blocks synaptic scaling, a form of homeostatic plasticity that buffers the impact of prolonged reductions or increases in network activity. Unexpectedly, we found that the six individual enzymes are all necessary for synaptic scaling and that the roles of KMT2 enzymes segregate into evolutionary-defined subfamilies: KMT2A and KMT2B (fly-Trx homologs) for synaptic downscaling, KMT2C and KMT2D (Trr homologs) for upscaling, and KMT2F and KMT2G (dSet homologs) for both directions. Selective blocking of KMT2A enzymatic activity by a small molecule and targeted disruption of the enzymatic domain both blocked the synaptic downscaling and interfered with the activity-dependent transcriptional program. Furthermore, our study revealed specific phases of synaptic downscaling, i.e., induction and maintenance, in which KMT2A and KMT2B play distinct roles. These results suggest that mammalian brains have co-opted intricate H3K4me installation to achieve stability of the expanding neuronal circuits.

Neutralization, effector function and immune imprinting of Omicron variants.

Currently circulating SARS-CoV-2 variants have acquired convergent mutations at hot spots in the receptor-binding domain1 (RBD) of the spike protein. The effects of these mutations on viral infection and transmission and the efficacy of vaccines and therapies remains poorly understood. Here we demonstrate that recently emerged BQ.1.1 and XBB.1.5 variants bind host ACE2 with high affinity and promote membrane fusion more efficiently than earlier Omicron variants. Structures of the BQ.1.1, XBB.1 and BN.1 RBDs bound to the fragment antigen-binding region of the S309 antibody (the parent antibody for sotrovimab) and human ACE2 explain the preservation of antibody binding through conformational selection, altered ACE2 recognition and immune evasion. We show that sotrovimab binds avidly to all Omicron variants, promotes Fc-dependent effector functions and protects mice challenged with BQ.1.1 and hamsters challenged with XBB.1.5. Vaccine-elicited human plasma antibodies cross-react with and trigger effector functions against current Omicron variants, despite a reduced neutralizing activity, suggesting a mechanism of protection against disease, exemplified by S309. Cross-reactive RBD-directed human memory B cells remained dominant even after two exposures to Omicron spikes, underscoring the role of persistent immune imprinting.

Antiviral mechanisms of two broad-spectrum monoclonal antibodies for rabies prophylaxis and therapy.

Rabies is an acute and lethal encephalomyelitis caused by lyssaviruses, among which rabies virus (RABV) is the most prevalent and important for public health. Although preventable through the post-exposure administration of rabies vaccine and immunoglobulins (RIGs), the disease is almost invariably fatal since the onset of clinical signs. Two human neutralizing monoclonal antibodies (mAbs), RVC20 and RVC58, have been shown to be effective in treating symptomatic rabies. To better understand how these mAbs work, we conducted structural modeling and in vitro assays to analyze their mechanisms of action, including their ability to mediate Fc-dependent effector functions. Our results indicate that both RVC20 and RVC58 recognize and lock the RABV-G protein in its pre-fusion conformation. RVC58 was shown to neutralize more potently the extra-cellular virus, while RVC20 mainly acts by reducing viral spreading from infected cells. Importantly, RVC20 was more effective in promoting effector functions compared to RVC58 and 17C7-RAB1 mAbs, the latter of which is approved for human rabies post-exposure treatment. These results provide valuable insights into the multiple mechanisms of action of RVC20 and RVC58 mAbs, offering relevant information for the development of these mAbs as treatment for human rabies.