Citations

53BP1 nuclear bodies are dynamic structures with properties resembling biomolecular condensates, but the molecular determinants that govern 53BP1 higher-order assembly at DNA double-strand breaks (DSBs) remain to be established. Here, we show that 53BP1 condensation is stimulated by phosphatidylinositol 3-phosphate (PI(3)P) in vitro through a highly specific interaction with its C-terminal tandem BRCT domain (tBRCT). Consequently, mutational inactivation of the 53BP1 tBRCT domain compromised PI(3)P binding and suppressed 53BP1 optodroplet formation in vivo. We further show that rapid 53BP1 clustering following DNA damage precedes its stable assembly on DSB-flanking chromatin, requires its tBRCT, and is suppressed by sequestration of nuclear PI(3)P. Taken together, our findings identify PI(3)P binding as a mechanism that promotes the formation and maturation of 53BP1 condensate-like assemblies on damaged chromatin.

Background/Aims: Infections with drug-resistant organisms (DROs) are associated with poor outcomes in cirrhosis. Rifaximin, widely used for hepatic encephalopathy (HE), could promote cross-resistance, but data regarding clinical impact are conflicting. Aim: Determine predictors of DROs in a global cirrhosis inpatient cohort focusing on preadmission rifaximin use.Methods: From the global CLEARED consortium, we focused on cirrhosis inpatients with infections on/during admission. Clinical/demographic/medication, especially rifaximin details were recorded. The primary outcome was DRO development. Multivariable regression for DRO including clinical, medications, and country income was performed.Results: 2,949 infected inpatients (55.3 years, 62.9% male) were included. 12.2% of all and 24.4% of culture-positive infections developed DROs; these patients had higher HE (39 vs. 31%, <i>P</i>=0.003), hepatorenal syndrome (25 vs. 19%, <i>P</i>=0.006), lactulose (55 vs. 47%, <i>P</i>=0.008) and rifaximin use (34 vs. 27%, <i>P</i>=0.006) on crude comparisons but country-income distributions were similar. 29.7% were on pre-admission rifaximin, mostly HE-related; they had more advanced cirrhosis and from low/low-middle-income countries. Daptomycin was used in 1.5%, linked with DROs (5.0 vs. 1.0%, <i>P</i><0.0001) without a difference in rifaximin use (1.4 vs.1.7%, <i>P</i>=0.61). On adjusted analysis, MELD-Na (1.03, 95% CI 1.02–1.04, <i>P</i><0.001) increased, whereas male sex (0.73, 95% CI 0.58–0.92, <i>P</i>=0.008) and hepatitis-B (0.65, 95% CI 0.45–0.92, <i>P</i>=0.020) decreased DRO. Rifaximin was not associated with DROs overall (OR 1.07, 95% CI 0.80–1.43, <i>P</i>=0.65) or within income strata (high: 1.07, 95% CI 0.59–1.92, <i>P</i>=0.82, upper-middle: 1.18, 95% CI 0.74–1.85, <i>P</i>=0.49, low/low-middle: 1.04, 95% CI 0.60–1.81, <i>P</i>=0.90) despite sensitivity analyses.Conclusions: In this large global cohort of hospitalized patients with cirrhosis and infections, 12% developed infections involving DROs. 30% had pre-admission rifaximin use which was not linked with daptomycin use or with DRO development on adjusted analysis overall or across country income groups.

Abstract Intercellular communication between multiple myeloma (MM) cells and osteoclast precursor cells (pre-OCs) contributes extensively to the occurrence and development of myeloma-related bone destruction. However, key interacting modes and the exchanged substances involved in this communication remain unclear. In this study, we discover that tunneling nanotubes (TNTs) directly connect MM and pre-OCs. Using the stable isotope labeling with amino acids in cell culture assay and a positive-negative double selection strategy, we identify filamin A (FLNA) as a major protein transported from MM to pre-OCs. FLNA acts as a molecular clutch linking extracellular matrix–bound MAC1 to the cytoskeleton, activating Rho and MAPK signaling pathways and promoting F-actin polymerization, which subsequently enhances osteoclast differentiation by modulating cellular stiffness, traction force, and deformability. In addition, FLNA directly binds vinculin and promotes its recruitment to podosomes, thereby enhancing the functions of podosomes and the bone resorption capacity of osteoclasts. The conditional depletion of Flna in mice suppresses podosome activity and reduces stiffness, traction force, and deformability in pre-OCs, leading to significantly impaired osteoclast differentiation and increased bone mass. In the Vk∗MYC mouse model of myeloma, the administration of the TNT inhibitor latrunculin B disrupts FLNA transport to osteoclasts and alleviates osteolytic bone disease. These findings highlight the critical role of MM-transferred FLNA in osteoclastogenesis and suggest that targeting TNTs may represent a therapeutic strategy to limit pathological bone resorption associated with MM.

BACKGROUND Perineural spread (PNS) of colorectal carcinoma (CRC) is a rare and challenging diagnosis. Its clinical and radiological presentation is often subtle and can overlap with radiation-induced neuropathy and malignant nerve tumors, complicating timely diagnosis. The role of circulating tumor DNA (ctDNA) in the detection of PNS has not been previously described. OBSERVATIONS A 48-year-old man with a history of rectal cancer and perineural invasion presented with progressive, refractory sciatic neuropathic pain. Conventional surveillance imaging was initially negative despite subtle rising of carcinoembryonic antigen and ctDNA levels. Subsequent MRI revealed abnormalities of the lumbosacral plexus and sciatic nerve, and fascicular biopsy confirmed metastatic CRC involving the sciatic nerve, establishing the diagnosis of PNS. LESSONS This case highlights PNS as a rare but important consideration in patients with focal neuropathic symptoms and prior CRC. Circulating tumor DNA positivity may serve as an early indicator of occult tumor activity even within the nerves when imaging is equivocal. However, currently histopathological confirmation remains the only definitive method to distinguish PNS from alternative diagnoses and is essential to guide appropriate management. https://thejns.org/doi/10.3171/CASE25997

Abstract Background Progressive supranuclear palsy (PSP) is a tauopathy for which there is limited understanding of epidemiological risk factors. Objective The objective of this study was to identify premorbid nonmedical and medical risk factors for PSP diagnosis in a large prospective population‐based cohort. Methods We performed a matched nested case–control study using the UK Biobank (UKB) cohort consisting of >500,000 adults aged 37 to 73 years. PSP diagnoses were identified from 2007 to censor date (August 2025) and matched 1:10 by age and sex to control subjects without parkinsonism or dementia diagnoses. We derived risk factors using an iterative logistic regression approach. Results There were 240 incident PSP diagnoses in the UKB. In the fully adjusted model, premorbid depression (odds ratio [OR], 3.22; 95% confidence interval [CI], 2.30–4.50; P < 0.001), delirium (OR, 6.76; 95% CI, 4.08–11.19; P < 0.001), and functional gastrointestinal disorders (OR, 1.91; 95% CI, 1.39–2.63; P < 0.001) were associated with increased risk. Heavy alcohol consumption was associated with higher risk compared with moderate consumption (OR, 1.65; 95% CI: 1.21–2.26; P = 0.0017). Body mass index (BMI) and alcohol consumption had nonlinear risk profiles. Cancer diagnosis was inversely associated with PSP (OR, 0.56; 95% CI, 0.40–0.79; P < 0.001). Depression and delirium diagnoses remained significant 5 to 10 years before diagnosis. Conclusions In this large prospective cohort, PSP was associated with premorbid lifestyle practices and neuropsychiatric diagnoses years before diagnosis. This suggests a long premotor phase and highlights opportunities for earlier diagnosis and further mechanistic investigation. The inverse association with cancer mirrors the relationship seen in other neurodegenerative conditions and may point toward shared mechanisms. © 2026 International Parkinson and Movement Disorder Society.

Abstract In many cancers, a major barrier to effective immunotherapy is the dominance of tumor-associated myeloid cells (TAMs), which establish a profoundly immunosuppressive tumor microenvironment (TME). This challenge is particularly pronounced in glioblastoma (GBM), where myeloid cells represent the predominant immune population and actively suppress antitumor immunity. Identifying targets that can reprogram TAMs from an immunosuppressive state toward a pro-inflammatory, antigen-presenting phenotype remains a critical unmet need. Here, we identify the voltage-gated proton channel Hv1 as an immune-restricted regulator of glioma-associated macrophage function. Hv1 is notable not only for its immune-specific expression but also for its established roles in central nervous system (CNS) pathologies, where Hv1 depletion alters microglial and macrophage polarization, reduces myeloid accumulation, dampens inflammatory cytokine production, and limits secondary tissue damage. However, Hv1’s role in shaping the GBM immune landscape—particularly in vivo—has remained poorly understood due to low Hvcn1 transcript abundance and the lack of reliable antibodies and genetic tools. Given the dominance of myeloid cells in GBM and their central role in tumor immune regulation, we sought to define Hv1 function within this highly immunosuppressive brain TME. Analysis of patient datasets revealed that elevated Hv1 expression correlates with poor clinical prognosis. Consistently, Hv1 loss significantly prolonged survival in multiple murine glioma models. Using in vivo two-photon imaging and spectral flow cytometry, we show that Hv1 depletion reprograms TAMs toward an anti-tumor phenotype characterized by enhanced tumor cell phagocytosis, improved antigen presentation, and increased T cell infiltration. By generating new Hv1 reporter and conditional mouse lines, we further demonstrate that tumor-associated microglia and infiltrating macrophages are the principal sources of Hv1 and markedly upregulate its expression in response to glioma. Notably, selective deletion of Hv1 in infiltrating macrophages phenocopied the survival benefit observed with global Hv1 loss. Mechanistically, using mass spectrometry and genetic models, we identify the Stimulator of Interferon Genes (STING) as a previously unrecognized binding partner of Hv1, placing Hv1 within the STING signaling pathway, a central regulator of innate and adaptive immune responses. Together, these findings fill a critical gap in understanding myeloid Hv1 function in GBM and identify Hv1 as a promising target for reprogramming the tumor immune microenvironment. Citation Format: Jiaying Zheng, Lingxiao Wang, Shunyi Zhao, Katayoun Ayasoufi, Meijie Wang, Praveen N. Pallegar, Peter R. Strege, Langni Liu, Yushan Wan, Wenjing Zhang, Emma N. Goddery, Manling Xie, Arthur Beyder, Aaron J. Johnson, Long-Jun Wu. Myeloid Hv1-STING axis tunes glioma immunity [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Brain Cancer; 2026 Mar 23-25; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2026;86(6_Suppl):Abstract nr A016.

Abstract INTRODUCTION Multicomponent non‐pharmacological interventions, such as the HABIT Healthy Action to Benefit Independence & Thinking® program, have shown promise for improving emotional well‐being, functioning, and self‐efficacy in both people with mild cognitive impairment (pwMCI) and their care partners. However, limited research has examined whether outcomes differ based on type of care partner who co‐enrolls with the pwMCI. METHODS We analyzed data from 875 pwMCI−care partner dyads who completed the HABIT program. Multivariate linear mixed‐effects regression models evaluated changes from baseline in outcomes by care partner type (spouse vs. non‐spouse) at post‐intervention, 6‐months, and 12‐ months. RESULTS At post‐intervention, pwMCI with spousal care partners demonstrated significant improvements across all outcomes from baseline, whereas those with non‐spousal partners improved in five out of seven outcomes. Across subsequent follow‐ups, pwMCI with spousal care partners showed sustained mean reductions in anxiety (post‐intervention: −2.0; 12‐month: −0.9) and increased compliance (post‐intervention: 5.7; 12‐month: 0.9). Everyday functioning in memory (post‐intervention: −0.9; 12‐months: 1.8) and executive functioning (post‐intervention: −0.7; 12‐months: 4.8) improved at post‐intervention but declined thereafter. Spousal care partners reported reduced anxiety (−1.2) and depression (−1.3) at post‐intervention, but by 12‐months they experienced increased burden, anxiety, and depression relative to baseline. Non‐spousal pwMCI–care partner dyads did not show significant change at 6 or 12‐months. DISCUSSION The HABIT intervention may have more favorable outcomes for pwMCI and care partners in spousal compared to non‐spousal dyads. These findings highlight the potential impact of care partner characteristics on both immediate and long‐term response to behavioral interventions for MCI. Highlights At post‐intervention, people with mild cognitive impairment (pwMCI) with spousal care partners showed significant improvements across all outcomes, while those with non‐spousal partners improved in five of seven outcomes. Gains attenuated over time for both spousal and non‐spousal dyads Spousal care partners reported reduced anxiety and depression at post‐intervention, but by 12 months they experienced increased burden, anxiety, and depression relative to baseline. Non‐spousal pwMCI–care partner dyads did not show significant change at 6 or 12 months.

Stereotactic arrhythmia radiotherapy (STAR) is emerging as a highly effective treatment for ventricular tachycardia (VT). Growing evidence indicates that STAR favorably reprograms the electrical substrate by speeding conduction and/or prolonging repolarization via modulation of ion channel expression, although the mechanisms by which single-fraction radiation mediates durable changes in gene expression are incompletely understood. Here, we identify dynamic changes in the cardiomyocyte epigenome and transcriptome after irradiation (IR) in vivo and in vitro, including durably increased expression and chromatin accessibility of Scn5a (encodes the α subunit of the sodium channel, Na V 1.5), demonstrating a role for epigenetic memory in conduction velocity (CV) increases observed after STAR. Transcriptomic and epigenetic sequencing further identified dynamic changes in gene expression and regulatory regions involved in cellular repolarization, calcium handling, and metabolism after IR. These changes were mirrored by dose-dependent and cell-autonomous changes in repolarization, calcium flux, and mitochondrial respiration, highlighting important cellular processes that may mediate the therapeutic effects of STAR. Overall, we found that cardiomyocytes exposed to a single fraction of high-dose IR exhibited epigenetic reprogramming that mediated broad and dynamic physiologic responses.