Citations

Abstract Metabolic reprogramming is a fundamental determinant of immune cell fate and effector function during inflammation, yet how distinct metabolic pathways regulate pathogenic lung macrophage activity and contribute to fibrotic remodeling remains incompletely understood. Here, we integrated single-cell RNA sequencing, lineage-specific genetic mouse models, and fate-mapping approaches to define the metabolic pathways that regulate the pro-fibrotic activity of lung macrophages. We found that such cells undergo pronounced aerobic glycolysis in the bleomycin-induced mouse model of pulmonary fibrosis. Myeloid cell-specific depletion of lactate dehydrogenase A (Ldha), but not of mitochondrial pyruvate carrier (Mpc), markedly attenuated lung fibrosis and improved survival. Mechanistically, enhanced glycolytic flux increased lactate production, which promoted histone lysine lactylation and facilitated Arginase 1 (Arg1) expression in lung macrophages, thereby driving fibrotic progression. Using monocyte fate-mapping, we further demonstrated that Arg1 expression is largely restricted to recruited monocyte-derived macrophages rather than lung-resident macrophages. Notably, selective deletion of Ldha in granulocyte-monocyte progenitors and their progeny was sufficient to suppress Arg1 expression and reduce fibrosis severity. In human lung samples, we observed significantly elevated expression of ARG1 and key glycolytic enzymes in patients with idiopathic pulmonary fibrosis, despite species-specific differences in the immune cell types expressing ARG1. Together, these findings identify an aerobic glycolysis–lactate–histone lactylation axis that regulates pro-fibrotic myeloid cell function and represents a potential therapeutic target in pulmonary fibrosis.

Sharing research code in an open access version-controlled repository offers significant benefits for both science as a whole and for individual researchers. In this article, we focus on this practice, which is fully aligned with the NIH’s Gold Standard Science (GSS) program as well as FAIR (findable, accessible, interoperable, reusable) and TRUST (transparency, responsibility, user focus, sustainability, technology) principles. Gold Standard Science supports open science by emphasizing transparency, reproducibility, and the use of best practices that enable others to verify and extend research. Pairing a research article’s cited data snapshot with a versioned, environment-specific code release, deposited in a companion code repository, ensures that, upon submission to a medical journal, readers and reviewers can directly verify results. An executable and updatable companion code repository complements, rather than replaces, established research data repositories. When code underlying medical research results is made openly available, then other scientists can inspect, run, and validate analyses. These activities enhance reproducibility, which is a core aim of GSS. Shared code also facilitates collaborative innovation by allowing researchers to extend the utility of the code to new datasets and applications. For researchers, code sharing can increase visibility, credibility, and citation impact. Demonstrating transparency through shared executable and updatable code builds trust with journal readers, peer reviewers, funders, and peers. Shared code in an open access repository signals adherence to high standards of scientific integrity and attracts opportunities for collaboration. A researcher who shares code receives recognition as a leader in reproducible, trustworthy research consistent with NIH’s GSS principles.

The success of living donor liver transplantation (LDLT) has bridged the growing gap between organ demand and availability in patients with liver failure or liver cancer. Safety of the living liver donor (LLD) is paramount, and astute intraoperative management plays a critical role in ensuring optimal outcomes for them. Given that intraoperative surgical and anesthesia practices vary widely across centers, the International Liver Transplantation Society (ILTS) and the International Living Donor Liver Transplantation Group (iLDLT Group) convened a global consensus conference in Toronto in March 2025 to develop guidelines for intraoperative management of the LLD. This manuscript details the recommendations on intraoperative considerations for the safety of LLD developed by Working Group II of the Consensus Scientific Committee, using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system for assessment of recommendations, and the Danish model of consensus. Working Group II focused on intraoperative monitoring, fluid and ventilation strategies, surgical techniques for vascular and biliary division, surgeon and center-specific experience, and intraoperative crises planning. These guidelines aim to support both established and emerging LDLT teams to ensure high-quality and safe intraoperative care for the LLD.

ABSTRACT Introduction Although covalent Bruton's tyrosine kinase inhibitors (cBTKis) have transformed treatment of chronic lymphocytic leukemia and small lymphocytic leukemia (CLL/SLL), cBTKi‐related cardiotoxicity is a known side effect. This real‐world study evaluated incident cardiovascular adverse events (CVAE), healthcare resource utilization (HCRU), and costs among patients with CLL/SLL receiving cBTKis. Methods Adult patients with CLL/SLL who initiated ibrutinib or acalabrutinib treatment (index date) between 2020 and 2023 were identified using US claims data and followed up to 36 months post‐index. Incident CVAEs (not present pre‐index) were assessed during cBTKi treatment and patients were stratified by CVAE status. HCRU and costs were evaluated per 1000 patient‐months (PPPM). Results Overall, 2069 patients were identified (mean age of 73.7 ± 9.1 years, 40.4% female) with a mean treatment‐specific observation period of 11.4 ± 9.5 months. At least one incident CVAE was observed in 442 (21.4%) patients. The incidence rate was 21.6 PPPM for hypertension, 8.9 PPPM for atrial fibrillation, 8.6 PPPM for ventricular arrhythmias, and 8.3 PPPM for atrial flutter. Patients with incident CVAEs had significantly more total medical service days PPPM (4334 vs. 3138, p < 0.001), primarily driven by increased inpatient (690 vs. 230), outpatient (2798 vs. 2425), other visit (662 vs. 375), and ER days (184 vs. 109) than those without CVAEs. Total healthcare costs (PPPM) were substantially higher for patients with incident CVAEs ($20,250,560 vs. $17,413,460, p < 0.001) mainly due to higher inpatient ($3,417,948 vs. $915,839, p < 0.001), outpatient ($2,415,060 vs. $1,769,628, p < 0.01), and ER costs ($186,820 vs. $87,585, p < 0.001). Conclusions The observed class‐effect of high CVAEs with cBTKis underscores the unmet need for safer, more selective agents for CLL/SLL treatment. The HCRU and economic burden remain high for CLL/SLL, especially among patients experiencing CVAEs during cBTKi treatment. These findings emphasize the importance of optimizing clinical management to reduce CVAE risk and downstream impacts on HCRU and costs.

Background: Accurate characterization of tumor stiffness and adhesion is crucial when surgically resecting meningiomas. Currently, such determinations are difficult to ascertain through standard preoperative imaging diagnostics and clinical experience. Herein, we explored magnetic resonance elastography (MRE) as a means of assessing these parameters and thereby improving neurosurgical resections. Methods: This prospective study of 193 patients with meningiomas involved three distinct patient subsets (cohort 1, 88 [2017–2021]; cohort 2, 55 [2022–2023]; cohort 3, 50 [2023–2024]. We analyzed preoperatively obtained MRE data on meningioma stiffness (cohorts 1 and 2) and adhesion (cohort 2) for accuracy, while matching subjects with or without MRE studies (cohort 3, 1:1 ratio) to define the role of preoperative MRE in improving operative outcomes. Results: Areas under the curve (AUCs) for MRE in gauging meningioma stiffness and adhesion were 0.87 and 0.89, respectively. Both parameters significantly surpassed empiric predictions of stiffness and adhesion rendered by surgeons and radiologists, based on routine magnetic resonance imaging (MRI). MRE-determined stiffness measures independently correlated with prolonged resection duration, whereas MRE-assessed adhesion showed independent associations with increased blood loss, longer duration of tumor resection, and higher risk of pial injury. Ultimately, results based on cohort 3 demonstrated that MRE has great potential in this setting to improve neurosurgical procedures by significantly reducing intraoperative bleeding, resection duration, and risks of pial injury. Conclusion: MRE is a promising, noninvasive tool for accurately assessing meningioma stiffness and adhesion, standing to improve the precision and safety of needed surgical intervention.

Abstract Pseudouridine (Ψ) is the most prevalent RNA modification in human cells. Although Ψ was among the first post-transcriptional modifications discovered (1951), its biological functions remain poorly understood. More recently, Ψ was incorporated into COVID-19 mRNA vaccine, where it enhances RNA stability and reduces innate immune sensing. However, the precise roles of RNA Ψ in cancer, including leukemia, are largely unknown. Here, we identify RNA Pseudouridine Synthase D4 (RPUSD4) as a novel vulnerability in acute myeloid leukemia (AML) via directly catalyzing mitochondrial RNA (mt-RNA) Ψ formation. We further provide proof-of-concept evidence that targeting RPUSD4 suppresses leukemogenesis and stimulates anti-leukemia immunity. To investigate whether RNA Ψ dysregulation is involved in leukemia, we first compared RNA Ψ levels between primitive CD34+ cells (LSC-enriched) and CD34- bulk cells from multiple primary AML specimens. CD34+ AML cells exhibited significantly elevated RNA Ψ levels. We also examined Ψ levels across various RNA types in AML cells, identifying that mt-RNA contained much higher Ψ levels than other RNA types. These findings imply that RNA Ψ, particularly mt-RNA Ψ, may play a role in LSC biology and leukemogenesis. Further unbiased CRISPR screening revealed RPUSD4 as the most critical Ψ synthase for LSC maintenance. Large-scale transcriptomic and patient data analyses showed that RPUSD4 is highly expressed in AML specimens (P = 3.5 × 10-9), particularly within LSCs (P = 1.4 × 10-18). RPUSD4 knockout (KO) significantly suppressed AML proliferation, reduced mitochondrial OxPhos, and decreased LSC frequency in vitro and substantially delayed AML progression in vivo (MLL-r and FLT3ITD models). Of note, RPUSD4 KO-mediated anti-leukemia effects could be fully rescued by wild-type but not catalytically inactive RPUSD4 both in vitro and in vivo, demonstrating that Ψ synthase activity is essential for its function in leukemia. To profile RPUSD4-dependent Ψ sites, we applied two orthogonal technologies, direct nanopore sequencing and PRAISE sequencing (PMID: 36997645), both capable of detecting Ψ at single-base resolution. These approaches converged on a single RPUSD4-dependent Ψ at position 3,067 on mt-16S rRNA. This Ψ site is essential for maintaining rRNA stability. RPUSD4 KO induced mt-16S rRNA decay, thereby suppressing mitochondrial translation. This led to OxPhos inhibition, growth suppression, and LSC eradication in AML. Mechanistically, RPUSD4 is exclusively localized in mitochondria, where it directly interacts with the mt-RNA exonuclease PNPase. Under physiological conditions, PNPase resides within mitochondria and degrades mt-RNA to prevent accumulation of mitochondrial double-stranded RNA (mt-dsRNA). Upon RPUSD4 depletion, PNPase translocates from mitochondria to the cytosol, resulting in two major consequences: (i) mRNA decay:Cytosolic PNPase degrades mRNAs, particularly the nuclear-encoded mitochondrial mRNAs, such as DHODH(Dihydroorotate dehydrogenase). By retrogradely upregulating DHODH, RPUSD4 promotes de novo pyrimidine synthesis in AML. (ii) Aberrant mt-dsRNA accumulation: The buildup and cytoplasmic release of mt-dsRNA activates “viral mimicry” response that sensitizes AML cells to T cell cytotoxicity. Finally, to therapeutically target RPUSD4, we developed an RNA-based inhibitor, CpG-siRNARPUSD4, by conjugating a specific RPUSD4 siRNA to a Toll-like receptor (TLR9) ligand. CpG-siRNARPUSD4 is specifically internalized by TLR9+ cells, including AML cells, thereby maximizing selectivity and minimizing toxicity. Preclinical studies demonstrate that pharmacologically targeting RPUSD4 significantly prolonged survival across multiple AML models, including patient-derived xenograft (PDX) models, and rendered AML cells more susceptible to T cell–mediated cytotoxicity. Furthermore, the RPUSD4 inhibitor exhibited a promising synergistic effect with DHODH inhibitor in treating relapsed AML in vivo. For instance, in a representative relapsed PDX model, median survival times (in days) were: Ctrl – 28, RPUSD4 inhibitor – 36, DHODH inhibitor – 39, and combination – over 60. In conclusion, our findings uncover a previously unrecognized role of RPUSD4 and mt-RNA Ψ in leukemic metabolism, anti-leukemia immunity, and LSC maintenance. This study also bridges a critical knowledge gap regarding the role of RNA Ψ in leukemogenesis.

Abstract Approximately 17% of people aged 65 years and older are anemic, and 10% of death certificates report anemia as a secondary cause of death in the United States. Nonetheless, anemia remains unexplained in 30%-50% of older adults. This unexplained anemia of aging (UAA) is a diagnosis of exclusion. The mechanism, impact, and progression of UAA remain unknown. At older ages, anemia adds to pre-existing co-morbidities with significant adverse health consequences, representing a compelling unmet clinical concern. The National Institute on Aging held a workshop in 2024 to discuss current knowledge and research opportunities. Topics included the epidemiology of anemia at older age and its clinical implications; probable mechanism(s) underlying UAA, that is, low-grade inflammation’s effects on erythropoiesis; the role of microbiota in iron regulation in bone marrow; the importance of ruling out a diagnosis of leukemic clonal hematopoiesis (CH), which is more prevalent in older age; the role of senescence and aging governing hematopoiesis; and the effects of sex hormones on hematopoietic stem cell aging. Understanding the roles of these factors could reduce the proportion of the older anemic population whose anemia remains unexplained and offer insights into new potential diagnostic and intervention strategies. Speakers reviewed previous clinical trials in patients with UAA and CH. They discussed lessons learned and future research priorities, including efforts to develop new diagnostic algorithms and potential uses of machine learning.