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.

Common sex chromosome aneuploidies (SCAs) often present with cognitive and cardiovascular dysfunction in humans. To address SCA effects on gene expression and DNA methylation in relevant cell types, we differentiated neural precursor cells (NPCs) and cardiomyocytes (CMs) from human induced pluripotent stem cells (hiPSCs) with different numbers of sex chromosomes, including isogenic and independent lines. As expected, the expression of genes that escape X inactivation (escapees) mostly increases with the number of inactive X chromosomes (Xi). However, allelic analysis shows dampening of escapees specifically on the Xi in XXY compared to XX in both NPCs and CMs, revealing a novel type of dosage compensation in SCA. In contrast, Y-linked gene expression is higher in XXY versus XY NPCs, but the opposite is observed in CMs. This may explain the greater number of differentially expressed autosomal genes in NPCs versus CMs with an added Y chromosome, while effects of added X chromosomes are similar between cell types. Concordantly, changes in autosomal DNA methylation are mainly driven by the presence of a Y chromosome. These findings highlight the cell-type specificity of sex-linked and autosomal gene regulation in SCA conditions.

Background: Enteral phosphate replacement offers multiple advantages over intravenous phosphate replacement, but optimal dosing and administration are unclear. Objective: This study aimed to compare 2 different dosing strategies (PRE vs POST) of enteral phosphate replacement for mild hypophosphatemia (serum phosphorus = 2.1-2.5 mg/dL) and to evaluate our dosing strategy for moderate hypophosphatemia (serum phosphorus = 1.5-2 mg/dL) in critically ill patients. Methods: This single-center quasiexperimental, institutional review board–approved study was conducted in adult patients admitted to an intensive care unit (ICU) who received enteral phosphate replacement with a follow-up serum phosphorus level obtained within 24 hours of replacement. Patients were excluded if they had diabetic ketoacidosis, acute kidney injury, or received total parenteral nutrition or targeted temperature management. The mild PRE and POST groups received 48 and 72 mmol of enteral phosphate, respectively. The moderate group received 72 mmol of enteral phosphate. Effectiveness outcomes included normalization of serum phosphorus, defined as 2.6 to 4.5 mg/dL, and median change in phosphorus concentration. Safety outcomes included the incidence of new onset diarrhea and hyperphosphatemia (serum phosphorus >4.5 mg/dL) within 24 hours after phosphate replacement. Results: Of the 138 patients included, the median age was 59 (44-70) years and 69.6% were admitted to the surgical trauma ICU. Normalization of serum phosphorus occurred in 55 (58.2%) patients in mild PRE and 44 (72.7%) patients in mild POST ( P = 0.13). Change in serum phosphorus was 0.4 (0.1-0.9) mg/dL in mild PRE vs 0.7 (0.3-1.2) mg/dL in mild POST ( P = 0.06). Normalization occurred in 39 (66.7%) patients in the moderate group with a change in serum phosphorus of 1.0 (0.6-1.6) mg/dL. Rates of new onset diarrhea and hyperphosphatemia were not significantly different between groups. Conclusion and Relevance: Enteral phosphate replacement appears safe and effective in critically ill patients with mild-to-moderate hypophosphatemia and may serve as an alternative to intravenous phosphate.

The tumor microenvironment (TME) plays a crucial role in tumor progression and therapeutic response. Monocytes and macrophages, depending on their phenotype, can either enhance anti-tumor immunity or promote tumor growth by regulating cytokines such as IL-6. Multiple myeloma (MM), a hematologic malignancy, expresses the IL-6 receptor CD126 on its surface. Chimeric antigen receptor (CAR)-T cells targeting CD126 have been developed and shown to effectively eliminate CD126-positive tumor cells. However, interactions between macrophages, myeloma cells, and CAR-T cells require further investigation to optimize treatment strategies and minimize adverse effects. In this study, THP-1-derived macrophages, CD126 CAR-T cells, and MM cells, especially RPMI 8226 cells, were used to explore these interactions. A reduced cell population and an increased apoptosis of RPMI 8226 cells were observed in the presence of M1 macrophages. Metformin, known to influence IL-6 production, reduced the viability of RPMI 8226 cells with decreased CD126 expression. However, the killing activity of CD126 CAR-T cells against RPMI 8226 cells decreased after co-culture with macrophages, likely due to interactions between the CAR-T cells and the macrophages. These findings highlight the significant role of macrophages and inflammatory responses in MM progression and in modulating the efficacy of CAR-T cell therapy, providing valuable insights for the optimization of immunotherapeutic strategies.

Abstract In both type 1 and type 2 diabetes (T1D and T2D), insulin-producing β cells undergo progressive dysfunction due to inflammation, leading to impaired glucose responsiveness, dedifferentiation, and cell loss. While bile acid (BA) dysregulation under diabetic conditions is known to influence metabolic and inflammatory pathways, its mechanistic role in β cell regulation remains incompletely defined 1–3 . Here we show that bile acid sensor Farnesoid X receptor (FXR) and Bromodomain and Extra-Terminal motif (BET) signaling cooperatively regulates β cell inflammatory response and β cell identity. We identified the physiological protein-protein interaction between FXR and the bromodomain-containing protein 4 (BRD4) as a regulatory axis that protects against β cell dysfunction. We show that FXR activation by Fexaramine (Fex) together with BRD4 inhibition by JQ1 synergistically suppressed IL-1β-induced inflammation while also improving β cell identity and insulin secretion in both db/db model and high-fat diet (HFD) plus multi low-dose streptozotocin (MLD-STZ) model of diabetes. Importantly, this cooperative effect is abolished in β cell–specific FXR knockout (βFXRKO) mice, establishing that FXR is required for the functional synergy between these pathways in vivo . Mechanistically, structure-guided modeling and mutational analyses identified a direct interaction between FXR and the BD2 domain of BRD4, depending on specific lysine acetylation sites. Additionally, inhibition of the BD2 domain of BET combined with FXR activation markedly improved β cell survival in human T1D and T2D models established from human pluripotent stem cell (hPSC)-derived islet-like organoids (HILOs). Collectively, these findings establish a BA–bromodomain axis as a transcriptional interface linking metabolic signaling and chromatin regulation, and highlight FXR–BET targeting as a promising strategy to counter progressive β cell failure in diabetes.

ABSTRACT Background Quality of life and symptom burden of patients with myelofibrosis are well recognized and compounded in those with anemia; however, the effects of transfusion burden or anemia severity on quality of life have not been comprehensively characterized. This post hoc descriptive analysis explored the association between transfusion status or hemoglobin improvement and patient‐reported outcomes (PROs). Methods The analysis used pooled populations across treatment arms from 3 clinical trials (SIMPLIFY‐1, SIMPLIFY‐2, MOMENTUM); sample sizes for each PRO measure were dependent on the trials in which they were administered. Results At both baseline and week 24, transfusion independence was associated with umerically greater mean SF ‐36v2 and EORTC QLQ ‐ C30 scores than transfusion dependence; in the subgroup that was transfusion dependent at baseline, those who achieved transfusion independence at week 24 had greater PRO improvements than those who remained reliant on transfusions. Regardless of transfusion status, patients who achieved a hemoglobin improvement ≥ 1, ≥ 1.5, or ≥ 2 g/ dL from baseline also had clinically meaningful improvements in quality of life (assessed via mean EQ ‐ 5D ‐ 5L or SF ‐36v2 scores) and symptoms (assessed via PGIC or MPN ‐ SAF / MFSAF Total Symptom Score) at week 24 compared with those who did not. Conclusions Collectively, these results provide preliminary insights into the associations of transfusion status and anemia severity with quality of life in myelofibrosis; as current PRO measures do not directly evaluate the relationship between symptoms such as fatigue and anemia, development of new measures to more comprehensively capture the patient experience for those with anemia in myelofibrosis may be warranted. Trial Registration NCT01969838, NCT02101268, NCT04173494

Pulsed Electric Field (PEF) ablation is a non-thermal cancer treatment that disrupts tumor cell membranes while preserving the immune microenvironment and promoting immunogenic cell death. We present a case of a patient with metastatic hormone receptor-positive, HER2-low breast cancer who achieved a durable clinical response after PEF in combination with an immune checkpoint inhibitor (pembrolizumab). The patient remained off systemic therapy for 14 months without disease progression. Single-cell spatial molecular imaging (SMI) and gene set enrichment analysis (GSEA) were performed to evaluate immune microenvironment changes pre- and post-PEF treatment. Spatial transcriptomics of the tumor cell compartment revealed a post-PEF enrichment of immune-related pathways, including interferon alpha/beta and gamma signaling and MHC class I antigen processing and presentation, alongside increased infiltration of immune cells: CD8+ T cells, plasmablasts, and monocytes within the tumor neighborhood. This hypothesis-generating case suggests PEF’s potential to reshape the tumor-immune microenvironment when combined with immune checkpoint blockade, warranting further studies on its role in combination immunotherapy strategies.

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.

ABSTRACT Sodium glucose co‐transporter 2 inhibitors (SGLT2i) and glucagon‐like peptide‐1 receptor agonists (GLP‐1 RAs) are nephroprotective and their use is recommended for adults with chronic kidney disease (CKD). The role of SGLT2i and GLP‐1 RAs in patients with acute kidney injury (AKI) is unknown. This systematic review aimed to estimate the effect of SGLT2i or GLP‐1 RAs on clinical outcomes in AKI. We systematically searched Embase, MEDLINE, Scopus, Web of Science Core Collection, and clinical trials registries for observational studies and clinical trials from database inception to July 3, 2025. Included studies evaluated adults (≥ 18 years) with AKI during a hospitalization and compared patients subsequently exposed to either SGLT2i or GLP‐1 RAs to a non‐exposed control group. Random effects meta‐analyses were performed. Six studies related to SGLT2i (five observational, one randomized trial) and one related to GLP‐1 RAs (one observational) met eligibility criteria ( N = 432,048 patients). SGLT2i/GLP‐1 RA exposure was associated with lower odds of major adverse kidney events (MAKE) (OR 0.63, 95% CI 0.46–0.86) and all‐cause mortality [odds ratio (OR) 0.36, 95% confidence interval (CI) 0.21–0.62] compared to controls. The odds for kidney replacement therapy were lower with SGLT2i therapy in the three studies where it was evaluated (OR 0.61, 95% CI 0.40–0.93). Sensitivity analyses restricted to SGLT2i data were consistent with the overall findings [MAKE OR 0.63 (95% CI 0.42–0.95); Mortality OR 0.34 (95% CI 0.18, 0.65)]. Exposure to SGLT2i or GLP‐1 RAs after AKI, examined primarily in observational studies, was associated with improved clinical outcomes. These findings are promising and warrant evaluation in randomized clinical trials.