Alzheimer's disease (AD) arises from pathological interactions among diverse brain cell types, but cell-specific proteomic changes remain underexplored. Here, we present deep proteomic profiling of sorted or proximity-labeled brain cells from AD mouse models (5xFAD and AppNL-G-F) at multiple ages, quantifying 13,411 proteins in microglia (three subtypes), astrocytes, oligodendrocyte precursor cells, and neurons. We identified 3,028 differentially abundant proteins across these cell types, the majority of which were not detected in bulk proteomic datasets, and constructed cell type-specific networks to define functional modules and hub proteins. Comparison with transcriptomic data revealed that ~30% of proteomic changes are RNA-independent. Further analyses uncovered cross-cell type signaling proteins conserved in human AD brains, such as pleiotrophin (Ptn), which is transcriptionally enriched in astrocytes but accumulates in microglia. Importantly, recombinant PTN directly activates induced microglia-like (iMG) human cells. Thus, these findings provide a comprehensive cell type-resolved proteomic atlas of AD models, highlighting novel intra- and intercellular signaling events.

Data-independent acquisition (DIA) mass spectrometry enables rapid proteomic quantification, yet the reliability of statistical inference in DIA-based protein quantification remains incompletely understood. Here, we systematically evaluated missingness, false discovery rate (FDR), and statistical power, defined as true positive rate (i.e. sensitivity or recall), using technical replicates and a spike-in benchmark with known ground truth. Analysis of 18 HeLa replicates revealed persistent, abundance-dependent missingness. In the spike-in experiment with five replicates, human peptides were titrated against a stable yeast background, allowing fold changes (FCs) to be compared with expected values. Across comparisons with log2FCs ranging from 0.2 to 2.5, the nominal BH-FDR substantially underestimated the true FDR. For example, at a BH-FDR threshold of 0.05, the true FDR was ~0.2. Statistical power was ~40% for a log2FC of 0.2 and increased to nearly 100% for a log2FC of 2.5. Additional incorporation of FC thresholds improved the true FDR for large-FC comparisons, with slight loss of power, but markedly reduced sensitivity for small-FC comparisons. Together, these results indicate that nominal FDR does not necessarily reflect actual error rates in DIA proteomics and that DIA performance is influenced by protein abundance and expected fold changes. This study provides a framework for experimental design and data interpretation in DIA-based proteomic studies.

Incomplete quantification remains a persistent challenge in data-independent acquisition (DIA) mass spectrometry (MS), particularly in low-input and single-cell analyses. In identification-driven workflows, missing protein quantities often arise not from true absence of the corresponding peptides, but from failure to retain low-abundance signals from precursor or product ions for quantification. Here we present JUMPlion (local inference of ion-level missingness), a DIA quantification framework that re-examines MS raw files to recover missing values at the ion level before protein quantification. JUMPlion re-extracts precursor- and product-ion signals directly from raw data, infers ion-level measurements within precursor-specific local quantitative neighborhoods, and combines complementary precursor- and product-ion signals into downstream quantification. Using benchmark datasets acquired on multiple DIA platforms, JUMPlion increased protein-level completeness, improved fold-change accuracy, and enhanced detection of differentially abundant proteins while maintaining low differential-abundance false discovery rates. These gains were most evident in low-input and single-cell DIA datasets. Together, these results show that addressing missingness at the ion level before protein-level summarization can improve DIA quantification in diverse acquisition settings.

Children with favorable-histology Wilms tumor (FHWT) who relapse or whose tumors show blastemal predominance post-chemotherapy often face poor outcomes. The purpose of this study is to identify mechanisms of chemotherapy resistance in FHWT. We induce a patient-derived xenograft model (KT-47) to develop blastemal predominance after chemotherapy and to become resistant to vincristine, actinomycin-D, and doxorubicin (VAD). Multi-omics analyses reveal chromatin and transcriptional changes, including increased H3K4me3 and decreased H3K27me3 at stem cell and nephrogenesis gene loci. LIN28B is the most upregulated resistance-associated gene, linked to MYCN copy gain/upregulation and chromatin remodeling. ABCB1 expression correlates with interchromosomal enhancer interactions and functions as the mediator of chemotherapy resistance in vitro. These findings are validated in additional Wilms tumor models. Overall, resistance is associated with de-differentiation to a stem-like state and is driven by ABCB1 upregulation, suggesting that therapeutic strategies targeting chromatin regulation and drug efflux may be relevant in therapy-resistant Wilms tumor.

Cancer therapeutics frequently fail in clinical trials because of poor therapeutic index (efficacy-to-toxicity ratio). We systematically identified targets likely to have a good therapeutic index, revealing insulin receptor substrate 4 (IRS4) as a dependency in IRS4-expressing cancers. Pan-cancer analysis of pediatric-enriched cancers revealed IRS4 expression consistent with dependency in 68% of choroid plexus, 37% of malignant rhabdoid, 31% of NUT midline, and 5% of osteosarcomas, while in adult cancers, it was expressed in 8% of uterine leiomyosarcomas and 1 to 2% of lung squamous, stomach, and breast carcinomas. IRS4 expression in adult tumors was associated with enhancer hijacking rearrangements, including recurrent GATA3-IRS4 and ANKRD30A-IRS4 in breast cancer, while rhabdoid and NUT midline cancers expressed IRS4 epigenetically. IRS4 fueled cancer dependency through PI3K-Akt activation, and domain analysis revealed the PH and PTB domains, which have a predicted drug pocket, to be dispensable, suggesting degradation-based modalities. These data reveal IRS4 as a target in IRS4-expressing cancers and suggest inhibitory approaches.

Neurodegenerative diseases (NDs) pose clinical challenges due to their complexity and molecular heterogeneity. Here, we present a pan-neurodegeneration atlas (PanNDA) from multilayer, deep proteomic analysis of 2,279 human brain samples spanning 6 major NDs: Alzheimer’s disease (AD), Lewy body dementia (LBD), frontotemporal lobar degeneration with TDP-43 pathology, progressive supranuclear palsy with tau pathology, vascular dementia, and Parkinson’s disease. PanNDA integrates data from whole proteome, detergent-insoluble proteome, and posttranslational modifications (phosphorylation and ubiquitination), enabling intra- and inter-disease comparisons. Intra-disease analyses uncover distinct molecular subtypes (e.g., three in AD and four in LBD), reveal dysregulated pathways, and prioritize top-ranked proteins. Inter-disease comparisons identify shared alterations in NDs, such as GPNMB in microglial and lysosomal activation and NPTX2 in synaptic regulation, alongside disease-specific changes and hub regulators within protein networks. Overall, PanNDA provides a systems-level framework for understanding ND mechanisms and serves as a foundational resource that is accessible via an interactive website: https://penglab.shinyapps.io/pannda.

UBA1 is the primary ubiquitin-activating enzyme that initiates ubiquitination, which regulates protein function and turnover. Although UBA1 loss is cell lethal, silent mutations that reduce UBA1 mRNA levels cause spinal muscular atrophy X-linked 2 (SMAX2), a disorder marked by skeletal muscle weakness and wasting. However, it remains unexplored how UBA1 impacts the muscle proteome, and whether muscle weakness can arise from reducing UBA1 function solely in skeletal muscle. Here, we examined Drosophila and mice with muscle-targeted UBA1 knockdown and found that this intervention reduced protein ubiquitination, muscle function and lifespan. Integrated transcriptomic and proteomic analyses indicated that a limited set of proteins is modulated post-transcriptionally by Uba1 RNA interference (Uba1RNAi), suggesting that these UBA1-sensitive proteins rely on optimal UBA1 levels for degradation (Uba1RNAi-upregulated proteins) and stability (Uba1RNAi-downregulated proteins). Therefore, despite the general function of UBA1 in ubiquitination, UBA1 knockdown alters the levels of relatively few critical proteins, which may contribute to muscle weakness and SMAX2 pathogenesis. Moreover, although SMAX2-linked UBA1 mutations occur ubiquitously, experimental reduction of UBA1 function solely in skeletal muscle recapitulates key disease aspects, highlighting a possible muscle-centric origin of SMAX2.

The synaptic vesicle (SV) cycle is the fastest membrane trafficking and protein sorting process in biology. It underlies neuronal communication and cognition, yet synaptic function declines during normal aging, increasing vulnerability to neurologic disease. How the SV cycle is maintained across the lifespan of a complex organism remains unclear. Here, we used wild-type mice (C57BL/6J) to define the age- and sex-stratified molecular landscape of SVs and identified apolipoprotein E (APOE) as an abundant presynaptic protein further enriched in aged female samples. Super-resolution imaging, cell-type selective expression, and protease protection assays demonstrate that APOE originates from astroglia and associates with the cytosolic face of SVs. Using iGluSnFR and pHluorin optophysiology, we find that both decreased and increased APOE levels impair neurotransmission during stimulus trains. Together, these findings place APOE at the synapse and establish it as a cell-nonautonomous regulator of the SV cycle.

Ewing sarcoma (EWS) is a highly aggressive pediatric malignancy characterized by elevated expression of SLFN11, which impairs DNA repair by binding to and functionally inhibiting DNA repair complexes, thereby enhancing susceptibility to genotoxic therapies. However, relapse remains a major clinical challenge and is often accompanied by the emergence of therapeutic resistance linked to reduced SLFN11 expression. We hypothesized that SLFN11-deficient tumors undergo adaptive metabolic reprogramming to overcome chemosensitivity. Here, we leverage transcriptomic and metabolomic profiling in patient-derived EWS models to demonstrate that SLFN11 loss drives downregulated mitochondrial glycerol-3-phosphate dehydrogenase (GPD2) expression, higher accumulation of glycerol-3-phosphate, fatty acid unsaturation, and enhanced glycerophospholipid (GPL) biosynthesis. Subsequently, targeting GPL biosynthesis (FSG67) restored DNA-damaging agent (SN-38) sensitivity in SLFN11-deficient EWS model, revealing a potential metabolic vulnerability to overcome chemoresistance. Furthermore, SLFN11 knockout tumors exhibited an elevated phosphocholine/glycerophosphocholine ratio, offering a potential non-invasive diagnostic biomarker.

RATIONALE:Lung injury caused by influenza is a leading cause of respiratory infection-related morbidity and mortality worldwide. In its severe form, influenza can cause acute respiratory distress syndrome (ARDS), which manifests as severe hypoxemic respiratory failure. Survivors of the acute stage of ARDS may develop lung fibrosis. The mechanisms underlying fibrotic responses in this context are unknown. OBJECTIVES:In this study, we investigate fibroblast responses to influenza challenge. METHODS:We used single cell gene expression (scGEX) and two-dimensional liquid chromatography coupled with tandem/mass spectrometry (TMT-LC/LC-MS/MS) on lung tissue collected longitudinally in a murine model of influenza A virus (IAV) infection. MEASUREMENTS AND MAIN RESULTS:By TMT-LC/LC-MS/MS, we identified profound changes in the composition of the lung matrisome, which were most evident 10 days after infection. In this context, we identified transcriptional heterogeneity amongst proximal/adventitial fibroblasts expressing Pi16 and Col15a1 as well as a myofibroblast activation state characterized by expression of Tnc, Spp1, Grem1, and Cthrc1. This activation state was transcriptionally similar to those previously described in other contexts. CONCLUSIONS:Together, these data suggest compartmentalization and conservation of pulmonary fibroblast responses to lung injury of different primary etiologies.

Alzheimer's disease (AD) is characterized by amyloid plaques that form complex microenvironments in the brain. However, the molecular composition of these plaques and their temporal regulation are not well defined. Here, we developed a sensitive workflow for quantitative proteomic profiling of single plaques using refined laser capture microdissection and data-independent acquisition mass spectrometry (LCM-DIA-MS). From >200 plaques and control regions in AD mouse models (5xFAD and APP-KI) and human brains, we quantified >7,000 proteins, revealing stage-dependent, cell-type-related remodeling of the amyloid proteome (amyloidome). Temporal profiling uncovered early immune and lysosomal activation followed by engagement of RNA processing and synaptic pathways. Cross-model and cross-species analyses determined a conserved amyloidome including APOE, MDK, PTN, and HTRA1, validated by co-localization in imaging analysis. Network analysis highlighted modules in lipid transport, vesicle organization, and autophagy. These findings establish amyloid plaques as conserved, dynamic multicellular hubs that link amyloid accumulation to downstream cellular events.

Myelodysplastic syndromes (MDSs) are malignant hematopoietic stem and progenitor cell (HSPC) disorders that lead to ineffective blood production with poor outcomes. We previously showed that F-box only protein 11 (FBXO11) is downregulated in MDS, and here we report how this event contributes to disease progression. Integration of multiomics data revealed that the SCF-FBXO11 complex regulates spliceosome and ribosome components in a nucleophosmin 1 (NPM1)-centric network. FBXO11 facilitates the ubiquitylation of NPM1, whereby deletion of FBXO11 results in the reorganization of NPM1 and a de-repression of alternative splicing. Label-free total quantitative proteomics demonstrated that the FBXO11-NPM1 interactome was markedly downregulated in cells from patients with CD34+ MDS. In addition, we discovered that MYC was evicted from the FBXO11 promoter by TLR2 activation, revealing that it was a MYC target gene and explaining why FBXO11 expression was decreased in MDS. In MDS mouse models, genetic ablation of Fbxo11 exacerbated neutropenia concomitant with a profound decrease in NPM1 protein levels. Finally, we discovered rare mutations in FBXO11, which mapped to a previously unstudied functional intrinsically disordered region (IDR) in the N-terminus responsible for binding NPM1. These data support a model in which FBXO11 rewires RNA binding and ribosomal subnetworks through ubiquitylation of NPM1, ultimately restricting MDS progression.

Solubility regulates protein function, but how it is governed by aging remains elusive. Here, we utilized mass spectrometry to define the relative composition of the soluble and insoluble tissue/organ fractions during mouse aging. In the young, there is a wide (∼100-1,000×) range of insoluble/soluble protein ratios that differ tissue-specifically. With aging, some proteins become relatively more insoluble, while others are conversely regulated or unaffected. Age-related insoluble/soluble changes are not merely dictated by histological similarity, diverge in related tissues with distinct degeneration propensities, and correlate tissue-specifically with structural features. Proteins that become age-insoluble in multiple organs include aggregation-prone circulating factors and ectopically expressed proteins. For instance, although primarily expressed by the epidermis, hornerin insolubility increases with aging in skeletal muscle, and experimental hornerin upregulation causes muscle weakness. Thus, age-insoluble proteins are useful biomarkers but can also contribute to age-related functional decline, highlighting a multifaceted remodeling of the insolubilome with aging.

Diffuse leptomeningeal glioneuronal tumors (DLGNTs) are rare, and optimal treatment remains undefined. We aim to comprehensively characterize their clinical and molecular features, offering granular insights into presentations and therapies to elucidate prognostic factors and therapeutic targets. Histologic, molecular, and clinical data of 30 patients with DLGNT were analyzed. Median age at diagnosis was 7.5 years (range: 0.9–20 years). Disease was localized at diagnosis in 16 patients (53.3

Proteomic profiling of Alzheimer's disease (AD) brains has identified numerous understudied proteins, including midkine (MDK), that are highly upregulated and correlated with Aβ since the early disease stage, but their roles in disease progression are not fully understood. Here we present that MDK attenuates Aβ assembly and influences amyloid formation in the 5xFAD amyloidosis mouse model. MDK protein mitigates fibril formation of both Aβ40 and Aβ42 peptides in Thioflavin T fluorescence assay, circular dichroism, negative stain electron microscopy, and NMR analysis. Knockout of Mdk gene in 5xFAD increases amyloid formation and microglial activation. Further comprehensive mass spectrometry-based profiling of whole proteome and detergent-insoluble proteome in these mouse models indicates significant accumulation of Aβ and Aβ-correlated proteins, along with microglial components. Thus, our structural and mouse model studies reveal a protective role of MDK in counteracting amyloid pathology in Alzheimer's disease.

Ewing sarcoma (EWS) is an aggressive cancer in adolescents and young adults with frequent relapse rates and poor outcomes in recurrent or metastatic cases. Schlafen family member 11 ( SLFN11 ) gene is associated with the sensitivity to DNA-damaging agents (DDAs). The knockout of SLFN11 is associated with acquired chemoresistance in both cell lines and preclinical models. Here, we aimed to elucidate the metabolic underpinnings of SLFN11 -loss associated chemoresistance in patient derived cell lines of EWS. Our integrated transcriptomic and metabolomic analyses revealed downregulation of mitochondrial glycerol-3-phosphate dehydrogenase 2 ( GPD2 ) gene, which was accompanied by the upregulation of glycerophospholipid (GPL) biosynthesis pathway. Further, therapeutic targeting of lipid synthesis with the glycerol-3-phosphate acyltransferase 1 (GPAT1) inhibitor (FSG67) enhanced the efficacy of the DDA (SN-38) in SLFN11−/− cells. These findings indicate that SLFN11 loss-mediated chemoresistance can be targeted by blocking GPL biosynthesis in addition to DDA administration. ### Competing Interest Statement The authors have declared no competing interest. * EWS : ewing sarcoma SLFN11 : schlafen family member 11 DDA : DNA-damaging agent GPL : glycerophospholipid GPAT1 : glycerol-3-phosphate acyltransferase 1 GPD2 : glycerol-3-phosphate dehydrogenase 2 EWSR1 : ewing sarcoma breakpoint region 1 ETS : erythroblast transformation specific FLI1 : Friend Leukemia Integration 1 PARP : poly (ADP-ribose) polymerase G3P : glycerol-3-phosphate CCLE : Cancer Cell Line Encyclopedia DepMap : cancer dependency map CRISPR : clustered regularly interspaced short palindromic repeats RNAi : RNA interference FDR : false discovery rate TCGA : The Cancer Genome Atlas Program ESCLA : Ewing Sarcoma Cell Line Atlas RNA-seq : RNA sequencing PCA : principal component analysis PC1 : first principal component Log2FC : Log2 fold change WT : wild type SLFN11−/− : SLFN11 knock out Pearson R : Pearson correlation coefficient G3PS : glycerol-3-phosphate shuttle DHAP : dihydroxyacetone phosphate ETC : electron transport chain LC/MS : Liquid chromatography–mass spectrometry PE : phosphatidylethanolamine PC : phosphatidylcholine PI : phosphatidylinositol PG : phosphatidylglycerol PA : phosphatidic acid DAG : diacylglycerol AGPAT4 : 1-Acylglycerol-3-Phosphate O-Acyltransferase 4 MUFA : monounsaturated fatty acid 1H NMR : proton nuclear magnetic resonance PCh : phosphocholine GPC : glycerophosphocholine BRAID : Bivariate Response to Additive Interacting Doses GPAT1 : glycerol-3-phosphate acyltransferase 1 IAE : Index of Achievable Efficacy IDMA : inhibitory dose for the anchor drug IDMB : inhibitory dose for the partner drug EC50 : half maximal effective concentration RPA1 : replication protein A MCM3 : minichromosome maintenance complex component 3 CDC45 : cell division cycle 45 PCNA : proliferating cell nuclear antigen ATR : Ataxia Telangiectasia and Rad3-related CDT : chromatin licensing and DNA replication factor 1 DDB1 : damage-binding protein 1 CUL4 : cullin 4 NSCLC : non-small cell lung cancer ccRCC : clear cell renal cell carcinoma mTOR : mammalian target of rapamycin FASN : fatty acid synthase ACC : acetyl-CoA carboxylase SCD1 : stearoyl-CoA desaturase 1. American Lebanese Syrian Associated Charities, https://ror.org/03rx10x31

BACKGROUND Anthracyclines, a highly effective chemotherapy for many pediatric malignancies, cause cardiomyopathy, a major late effect in adult survivors. Biomarkers are needed for early detection and targeted interventions for anthracycline-associated cardiomyopathy. OBJECTIVES The aim of this study was to determine if serum proteins and/or metabolites in asymptomatic childhood cancer survivors can discriminate symptomatic cardiomyopathy. METHODS Using an untargeted mass spectrometry-based approach, 867 proteins and 218 metabolites were profiled in serum samples of 75 asymptomatic survivors with subclinical cardiomyopathy and 75 individually matched survivors without cardiomyopathy from SJLIFE (St. Jude Lifetime Cohort Study). Models were developed on the basis of the most influential differentially expressed proteins and metabolites, using conditional logistic regression with a least absolute shrinkage and selection operator penalty. The best performing model was evaluated in 23 independent survivors with severe or symptomatic cardiomyopathy and 23 individually matched cardiomyopathy-free survivors. RESULTS A 27-protein model identified using conditional logistic regression with a least absolute shrinkage and selection operator penalty discriminated symptomatic or severe cardiomyopathy requiring heart failure medications in independent survivors; 19 of 23 individually matched survivors with and without cardiomyopathy were correctly discriminated with 82.6% (95% CI: 71.4%-93.8%) accuracy. Pathway enrichment analysis revealed that the 27 proteins were enriched in various biological processes, many of which have been linked to anthracycline-related cardiomyopathy. CONCLUSIONS A risk model was developed on the basis of the differential expression of serum proteins in subclinical cardiomyopathy, which accurately discriminated the risk for severe cardiomyopathy in an independent, matched sample. Further assessment of these proteins as biomarkers of cardiomyopathy risk should be conducted in external larger cohorts and through prospective studies. (JACC CardioOncol. 2025;7:56-67) (c) 2025 The Authors. Published by Elsevier on behalf of the American College of Cardiology Foundation. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

The ubiquitin-proteasome system maintains proteostasis by degrading proteins that unfold and become insoluble upon stress. Some proteins have high insolubility in normal conditions because of their structure, subcellular localization, and interactions but it remains incompletely understood how the ubiquitin-proteasome system regulates them. Here, we utilized mass spectrometry to profile heat-induced solubility changes (insolubilome) and associated post-translational modifications in human cells (http://thermal-stress-insolubilome.stjude.org). We find that the solubility of several protein categories is oppositely modulated by thermal stress. Some proteins become more soluble upon heat shock, whereas others, including several ubiquitin-conjugating enzymes, become more insoluble. By analyzing the changes in protein abundance induced by RNAi for E2 ubiquitin-conjugating enzymes, we identify E2-specific biases in targeting proteins with higher-than-average insolubility. Analysis of the E3 ubiquitin ligase HUWE1, which was previously found to detect proteins with exposed hydrophobic residues, indicates that siHUWE1-downregulated proteins have higher-than-average insolubility, suggesting that HUWE1 stabilizes subsets of insoluble proteins. Altogether, this study identifies components of the ubiquitination cascade that control and remodel the solubility of the human proteome.

Enzymes play a pivotal role in orchestrating complex cellular responses to external stimuli and environmental changes through signal transduction pathways. Despite their crucial roles, measuring enzyme activities is typically indirect and performed on a smaller scale, unlike protein abundance measured by high-throughput proteomics. Moreover, it is challenging to derive the activity of enzymes from proteome-wide post-translational modification (PTM) profiling data. To address this challenge, we introduce enzyme activity inference with structural equation modeling under the JUMP umbrella (JUMPsem), a novel computational tool designed to infer enzyme activity using PTM profiling data. We demonstrate that the JUMPsem program enables estimating kinase activities using phosphoproteome data, ubiquitin E3 ligase activities from the ubiquitinome, and histone acetyltransferase (HAT) activities based on the acetylome. In addition, JUMPsem is capable of establishing novel enzyme-substrate relationships through searching motif sequences. JUMPsem outperforms widely used kinase activity tools, such as IKAP and KSEA, in terms of the number of kinases and the computational speed. The JUMPsem program is scalable and publicly available as an open-source R package and user-friendly web-based R/Shiny app. Collectively, JUMPsem provides an improved tool for inferring protein enzyme activities, potentially facilitating targeted drug development. JUMPsem is a scalable and publicly available tool for inferring protein enzyme activities, potentially facilitating targeted drug development.

Non-tuberculous mycobacteria are emerging pathogens with high intrinsic drug resistance. Among these, Mycobacterium abscessus is particularly refractory owing to its extensive array of resistance mechanisms. Here we introduce florfenicol amine (FF-NH2), a major metabolite of the antibiotic florfenicol, which acts as a prodrug with narrow-spectrum activity against M. abscessus-chelonae complex species. FF-NH2 leverages intrinsic M. abscessus resistance conferred by the transcription factor WhiB7. It avoids WhiB7-dependent resistance mediated by the O-acetyltransferase Cat and is activated by the WhiB7-dependent N-acetyltransferase Eis2 in a prodrug fashion to generate the active translational inhibitor FF acetyl (FF-ac). FF-NH2 induces Eis2 expression through WhiB7, creating a feed-forward bioactivation loop, which increases FF-ac accumulation and antimicrobial action. FF-NH2 displays antiresistance properties, can synergize with other antibiotics and mitigates toxicity linked to mammalian mitochondrial ribosome inhibition. Importantly, FF-NH2 demonstrated efficacy in a murine model of M. abscessus infection. These findings suggest intrinsic resistance can be exploited to develop safer and more effective treatments for this pathogen.