Biology subjects

Diwan, A.

Publications and source records attributed to Diwan, A..

15 recordsLinked to original sources

bioRxiv2026

Tryptophan Restores Recovery Competence Following Starvation in the Absence of Lysosomal Amino Acid Sensing

How organisms recover from starvation to nutrient-replete physiology remains poorly understood. In C. elegans, we previously observed that transcription factor hlh-30 or a combination of glucose and linoleic acid in its absence are essential for survival with refeeding following starvation, i.e. recovery competence. A forward genetic screen to evaluate mechanisms identified depd-5, which encodes a GATOR1 subunit, loss of which is expected to impair amino acid sensing with unrestrained raga-1 and mTOR activation. Surprisingly, glucose refeeding reduced recovery competence in depd-5(lf, loss-of-function) animals, which was rescued by amino acids, specifically tryptophan. Increasing tryptophan levels in depd-5(lf) worms through supplementation, reduced tryptophan catabolism with tdo-2 ablation and prolonged starvation restored recovery competence. raga-1(gf, gain-of-function) recapitulated whereas raga-1(lf) rescued the impaired recovery competence in starved depd-5(lf) worms. An analogous DEPDC5 mutation in mammalian cells impaired starvation-induced mTOR inactivation. We conclude that tryptophan counters unrestrained mTOR activity to restore recovery competence following starvation.

cell biology↗

bioRxiv2026

Impaired proteostasis is an early feature of the diabetic heart in humans and mice

Diabetes and obesity increase cardiac lipid levels leading to cardiomyopathy and heart failure. We hypothesized that intermittent fasting would reduce cardiac lipid levels. Surprisingly, intermittent fasting increased myocardial triglyceride content, but rescued mortality and attenuated cardiomyopathy in mice overexpressing cardiomyocyte acyl-CoA synthetase 1 (MHC-ACSL1). Lipid overload caused cardiomyocyte accumulation of polyubiquitinated protein aggregates containing desmin, a scaffolding intermediate filament protein, which intermittent fasting prevented. Furthermore, intermittent fasting reversed elevated myocardial C16:0 ceramide content, and knockdown of ceramide synthase CerS5 and CerS6 reduced palmitate-induced protein aggregation, highlighting a role for C16:0 ceramides in this pathology. Conversely, impairing aggrephagy with cardiomyocyte-specific p62 ablation induced heart failure in mice fed a high-fat diet, with paradoxically reduced cardiac lipid content. Crucially, non-failing diabetic human hearts also exhibited protein aggregate pathology. Taken together, these results demonstrate that impaired proteostasis characterizes cardiomyopathy from cardiac lipid overload and identify a promising new therapeutic target for this condition.

molecular biology↗

bioRxiv2026

Zinc excess promotes lysosome remodeling by activating HLH-30/TFEB through the action of the high zinc sensor HIZR-1.

Zinc is an essential element that plays many roles in animals. Since excess zinc is toxic, animals have evolved sophisticated mechanisms to achieve homeostasis. A conserved mechanism is to store excess zinc in specialized lysosomes, which contributes to zinc detoxification and provides a supply when zinc becomes limiting. In C. elegans excess zinc conditions promote an increase in lysosome-related organelles called bilobed granules. Defining how zinc-regulated transcription drives the observed lysosome remodeling is key to understanding zinc homeostasis processes. Here we describe a positively regulated zinc cascade controlled by hizr-1 and hlh-30/TFEB, which encode the C. elegans high zinc sensor and the master regulator of the autophagy-lysosomal pathway, respectively; essential for connecting excess zinc homeostasis to lysosome biogenesis and remodeling. Our transcriptomic, genetic, and bioinformatic studies indicate that hizr-1 and hlh-30 are necessary and sufficient to activate transcription of lysosome genes under excess zinc conditions. In our regulatory model, zinc binding activates HIZR-1 protein, which accumulates in the nucleus and activates genes containing the HZA enhancer, including hlh-30. HLH-30 protein accumulates in the nucleus and activates genes containing the E-box enhancer. Genetic analysis of loss-of-function mutants demonstrated that both hizr-1 and hlh-30 are necessary for animals to tolerate excess zinc. Furthermore, HLH-30 promotes the increase in the number of acidified compartments, whereas HIZR-1 promotes the increase in the volume of the expansion compartment. These results define a genetic pathway that responds to excess zinc by increasing the number of lysosome-related organelles and their capacity to store and detoxify cytosolic zinc.

genetics↗

bioRxiv2025

A Micro-Engineered Heart Tissue Model of Desmin-related Cardiomyopathy Caused by Mutant αB Crystalin

Protein quality control (PQC) is essential for maintaining sarcomere integrity in cardiomyocytes. Crystallin B chain (CRYAB) R120G mutation disrupts CRYABs chaperone activity, leading to aggregation of CRYAB and its client proteins (including Desmin), leading to Desmin-related cardiomyopathy (DRM). Prior experimental systems for modeling DRM linked to CRYAB require massive overexpression of CRYAB mutant isoforms, raising questions about translational relevance. Here, we establish the first model of CRYAB-linked DRM that uses genome-edited hiPSC together with isogenic controls, allowing us to study the impact of mutant CRYAB expressed at near endogenous levels. Within micro-engineered heart tissues (HT), CRYAB-R120G mutant hiPSC-derived cardiomyocytes recapitulated key DRM hallmarks, including Desmin and CRYAB aggregation, contractile dysfunction, and increased vulnerability to PQC pathway inhibition. CRYAB-R120G mutant HT also exhibited dysfunctional calcium-contraction coupling, which exacerbated contractile deficits at higher pacing frequencies. JAK1 inhibition with Itacitinib partially restored contractile function at higher pacing frequencies, suggesting JAK1 inhibition as a viable therapeutic strategy. By preserving human-specific structural and functional features, our {micro}HT platform enables mechanistic characterization of proteotoxic cardiomyopathies and offers a scalable system for targeted drug screening.

bioengineering↗

bioRxiv2024

Mitophagy Facilitates Cytosolic Proteostasis to Preserve Cardiac Function

BackgroundProtein quality control (PQC) is critical for maintaining sarcomere structure and function in cardiac myocytes, and mutations in PQC pathway proteins, such as CRYAB (arginine to glycine at position 120, R120G) and BAG3 (proline to lysine at position 209, P209L) induce protein aggregate pathology with cardiomyopathy in humans. Novel observations in yeast and mammalian cells demonstrate mitochondrial uptake of cytosolic protein aggregates. We hypothesized that mitochondrial uptake of cytosolic protein aggregates and their removal by mitophagy, a lysosomal degradative pathway essential for myocardial homeostasis, facilitates cytosolic protein quality control in cardiac myocytes. MethodsMice with inducible cardiac myocyte specific ablation of TRAF2 (TRAF2icKO), which impairs mitophagy, were assessed for protein aggregates with biochemical fractionation and super-resolution imaging in comparison to floxed controls. Induced pluripotent stem cell (iPSC)-derived cardiac myocytes with R120G knock-in to the CRYAB locus were assessed for localization of the CRYAB protein. Transgenic mice expressing R120G CRYAB protein (R120G-TG) were subjected to both TRAF2 gain-of-function (with AAV9-cardiac Troponin T promoter-driven TRAF2 transduction) and TRAF2 loss-of-function (with tamoxifen-inducible ablation of one Traf2 allele) in cardiac myocytes to determine the effect of mitophagy modulation on cardiac structure, function, and protein aggregate pathology. ResultsCardiomyocyte-specific ablation of TRAF2 results accumulation of mitochondrial and cytosolic protein aggregates and DESMIN mis-localization to protein aggregates. Isolated mitochondria take up cardiomyopathy-associated aggregate-prone cytosolic chaperone proteins, namely arginine to glycine (R120G) CRYAB mutant and proline to lysine (P209L) BAG3 mutant. R120G-CRYAB mutant protein increasingly localizes to mitochondria in human and mouse cardiomyocytes. R120G-TG mice demonstrate upregulation of TRAF2 in the mitochondrial fraction with increased mitophagy as compared with wild type. Adult-onset inducible haplo-insufficiency of TRAF2 resulted in accelerated mortality, impaired left ventricular systolic function and increased protein aggregates in R120G-TG mice as compared with controls. Conversely, AAV9-mediated TRAF2 transduction in R120G-TG mice reduced mortality and attenuated left ventricular systolic dysfunction, with reduced protein aggregates and restoration of normal localization of DESMIN, a cytosolic scaffolding protein chaperoned by CRYAB, as compared with control AAV9-GFP group. ConclusionsTRAF2-mediated mitophagy in cardiac myocytes facilitates removal of cytosolic protein aggregates and can be stimulated to ameliorate proteotoxic cardiomyopathy.

cell biology↗

bioRxiv2024

Lipopolysaccharide Induces Trained Innate Immune Tolerance in the Heart Through Interferon Signaling in a Model of Stress-Induced Cardiomyopathy

BackgroundAlthough the ability of the heart to adapt to environmental stress has been studied extensively, the molecular and cellular mechanisms responsible for cardioprotection are not yet fully understood. MethodsWe administered Toll-like receptor (TLR) agonists or a diluent to wild-type mice and assessed their potential to induce cardiac protection against injury from a high intraperitoneal dose of isoproterenol (ISO) administered 7 days later. Cardioprotective effects were analyzed through serum cardiac troponin I levels, immune cell profiling via flow cytometry, echocardiography, and multiomic single-nuclei RNA and ATAC sequencing. ResultsPretreatment with the TLR4 agonist lipopolysaccharide (LPS), but not TLR1/2 or TLR3 agonists, conferred cardioprotection against ISO, as demonstrated by reduced cardiac troponin I leakage, decreased inflammation, preservation of cardiac structure and function, and improved survival. Remarkably, LPS-induced tolerance was reversed by {beta}-glucan treatment. Multiomic analysis showed that LPS-tolerized hearts had greater chromatin accessibility and upregulated gene expression compared to hearts treated with LPS and {beta}-glucan (reverse-tolerized). The LPS tolerance was associated with upregulation of interferon response pathways across various cell types, including cardiac myocytes and stromal cells. Blocking both type 1 and type 2 interferon signaling eliminated LPS-induced tolerance against ISO, while pretreatment with recombinant type 1 and 2 interferons conferred cardiac protection. Multiomic sequencing further revealed enhanced cytoprotective signaling in interferon-treated hearts. Analysis of cell-cell communication networks indicated increased autocrine signaling by cardiac myocytes, as well as greater paracrine signaling between stromal cells and myeloid cells, in LPS-tolerized versus reverse-tolerized hearts. ConclusionsLPS pretreatment confers cardiac protection against ISO-induced injury through TLR4 mediated type 1 and 2 interferon signaling, consistent with trained innate immune tolerance. The observation that LPS-induced protection in cardiac myocytes involves both cell-autonomous and non-cell-autonomous mechanisms underscores the complexity of innate immune tolerance in the heart, warranting further investigation into this cardioprotective phenotype. Clinical PerspectiveO_ST_ABSWhat is new?C_ST_ABSO_LIThe Toll-like receptor 4 (TLR4) agonist lipopolysaccharide (LPS) confers cardiac protection against isoproterenol-mediated injury in a manner consistent with trained innate immune tolerance, which is reversed by {beta}-glucan treatment. C_LIO_LIActivation of type 1 and 2 interferon signaling, which is downstream of Toll-like receptor 4, is necessary and sufficient for LPS-induced cardiac protection. C_LIO_LILPS-tolerized hearts show heightened autocrine signaling by cardiac myocytes and, to a greater degree, increased cell-cell communication between cardiac myocytes and stromal and myeloid cells compared to reverse-tolerized hearts. C_LI What are the clinical implications?O_LITLR4 and interferon signaling play key roles in the establishment of cardiac protection and LPS-induced trained innate immune tolerance. C_LIO_LIThe protective effects of LPS are mediated by cell-autonomous and non-cell-autonomous mechanisms, suggesting that a deeper understanding of the molecular and cellular signatures of innate immune tolerance is required for the development of targeted approaches to modulate trained innate immunity, and consequently cytoprotection, in the heart. C_LI

immunology↗

bioRxiv2024

Lysosomal LRRC8 complex regulates lysosomal pH, morphology and systemic glucose metabolism

The lysosome integrates anabolic signalling and nutrient-sensing to regulate intracellular growth pathways. The leucine-rich repeat containing 8 (LRRC8) channel complex forms a lysosomal anion channel and regulates PI3K-AKT-mTOR signalling, skeletal muscle differentiation, growth, and systemic glucose metabolism. Here, we define the endogenous LRRC8 subunits localized to a subset of lysosomes in differentiated myotubes. We show LRRC8A regulates leucine-stimulated mTOR, lysosome size, number, pH, and expression of lysosomal proteins LAMP2, P62, LC3B, suggesting impaired autophagic flux. Mutating a LRRC8A lysosomal targeting dileucine motif sequence (LRRC8A-L706A;L707A) in myotubes recapitulates the abnormal AKT signalling and altered lysosomal morphology and pH observed in LRRC8A KO cells. In vivo, LRRC8A-L706A;L707A KI mice exhibit increased adiposity, impaired glucose tolerance and insulin resistance characterized by reduced skeletal muscle glucose-uptake, and impaired incorporation of glucose into glycogen. These data reveal a lysosomal LRRC8 mediated metabolic signalling function that regulates lysosomal activity, systemic glucose homeostasis and insulin-sensitivity.

cell biology↗

bioRxiv2024

Phosphorylation of CRYAB Induces a Condensatopathy to Worsen Post-Myocardial Infarction Left Ventricular Remodeling.

Protein aggregates are emerging therapeutic targets in rare monogenic causes of cardiomyopathy and amyloid heart disease, but their role in more prevalent heart failure syndromes remains mechanistically unexamined. We observed mis-localization of desmin and sarcomeric proteins to aggregates in human myocardium with ischemic cardiomyopathy and in mouse hearts with post-myocardial infarction ventricular remodeling, mimicking findings of autosomal-dominant cardiomyopathy induced by R120G mutation in the cognate chaperone protein, CRYAB. In both syndromes, we demonstrate increased partitioning of CRYAB phosphorylated on serine-59 to NP40-insoluble aggregate-rich biochemical fraction. While CRYAB undergoes phase separation to form condensates, the phospho-mimetic mutation of serine-59 to aspartate (S59D) in CRYAB mimics R120G-CRYAB mutants with reduced condensate fluidity, formation of protein aggregates and increased cell death. Conversely, changing serine to alanine (phosphorylation-deficient mutation) at position 59 (S59A) restored condensate fluidity, and reduced both R120G-CRYAB aggregates and cell death. In mice, S59D CRYAB knock-in was sufficient to induce desmin mis-localization and myocardial protein aggregates, while S59A CRYAB knock-in rescued left ventricular systolic dysfunction post-myocardial infarction and preserved desmin localization with reduced myocardial protein aggregates. 25-Hydroxycholesterol attenuated CRYAB serine-59 phosphorylation and rescued post-myocardial infarction adverse remodeling. Thus, targeting CRYAB phosphorylation-induced condensatopathy is an attractive strategy to counter ischemic cardiomyopathy.

cell biology↗

bioRxiv2023

Chimeric Antigen Receptor Macrophages Target and Resorb Amyloid Plaques in a Mouse Model of Alzheimer's Disease

Substantial evidence suggests a role for immunotherapy in treating Alzheimers disease (AD). Several monoclonal antibodies targeting aggregated forms of beta amyloid (A{beta}), have been shown to reduce amyloid plaques and in some cases, mitigate cognitive decline in early-stage AD patients. We sought to determine if genetically engineered macrophages could improve the targeting and degradation of amyloid plaques. Chimeric antigen receptor macrophages (CAR-Ms), which show promise as a cancer treatment, are an appealing strategy to enhance target recognition and phagocytosis of amyloid plaques in AD. We genetically engineered macrophages to express a CAR containing the anti-amyloid antibody aducanumab as the external domain and the Fc receptor signaling domain internally. CAR-Ms recognize and degrade A{beta} in vitro and on APP/PS1 brain slices ex vivo; however, when injected intrahippocampally, these first-generation CAR-Ms have limited persistence and fail to reduce plaque load. We overcame this limitation by creating CAR-Ms that secrete M-CSF and self-maintain without exogenous cytokines. These CAR-Ms have greater survival in the brain niche, and significantly reduce plaque load locally in vivo. These proof-of-principle studies demonstrate that CAR-Ms, previously only applied to cancer, may be utilized to target and degrade unwanted materials, such as amyloid plaques in the brains of AD mice. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=120 SRC="FIGDIR/small/538637v2_ufig1.gif" ALT="Figure 1"> View larger version (34K): org.highwire.dtl.DTLVardef@561cd6org.highwire.dtl.DTLVardef@17f362forg.highwire.dtl.DTLVardef@be83ecorg.highwire.dtl.DTLVardef@1c735ce_HPS_FORMAT_FIGEXP M_FIG Amyloid targeting CAR Macrophages engineered to secrete M-CSF promote their own local survival and expansion while resorbing amyloid plaques in the brains of Alzheimers disease APP/PS1 mice, resulting in significant local clearance of amyloid plaques of all sizes. C_FIG

immunology↗

bioRxiv2021

Dual Effects of NV-CoV-2 Biomimetic Polymer: An Antiviral regimen against COVID-19

Remdesivir (RDV) is the only antiviral drug so far approved for COVID-19 therapy by the FDA. However its efficacy is limited in vivo due to its low stability in presence of plasma. This paper compared the stability of RDV encapsulated with our platform technology based polymer NV-387 (NV-CoV-2), in presence of plasma in vitro and in vivo. Furthermore, a non- clinical pharmacology studies of NV-CoV-2 (Polymer) and NV-CoV-2-R (Polymer encapsulated Remdesivir) in both NL-63 infected and uninfected rats were done. In an in vitro cell culture model experiment, antiviral activity of NV-CoV-2 and NV-CoV-2-R are also compared with RDV. The results are (i) NV-CoV-2 polymer encapsulation protects RDV from plasma- mediated catabolism in vitro and in vivo, too. (ii) Body weight measurements of the normal (uninfected) rats after administration of the test materials (NV-CoV-2, and NV-CoV-2-R) show no toxic effects on them. (iii) NL-63 infected rats body weights and their survival length were like uninfected rats after treatment with NV-CoV-2 and NV-CoV-2-R, and the efficacy as an antiviral regimen were found in the order as below: NV-CoV-2-R > NV-CoV-2 > RDV. In brief, our platform technology based NV-387-encapsulated-RDV (NV-CoV-2-R) drug has a dual effect on coronaviruses. First, NV-CoV-2 itself as an antiviral regimen. Secondly, RDV is protected from plasma-mediated degradation in transit, rendering altogether the safest and an efficient regimen against COVID-19.

pharmacology and toxicology↗

bioRxiv2021

Nanoviricides platform technology based NV-CoV-2 polymer increases the half-life of Remdesivir in vivo

So far, there are seven coronaviruses identified that infect humans and only 4 of them belong to the beta family of coronavirus (HCoV-HKU1, SARS-CoV-2, MERS-CoV and SARS-CoV). SARS family are known to cause severe respiratory disease in humans. In fact, SARS-CoV-2 infection caused a pandemic COVID-19 disease with high morbidity and mortality. Remdesivir (RDV) is the only antiviral drug so far approved for COVID-19 therapy by the FDA. However, the efficacy of RDV in vivo is limited due to its low stability in presence of plasma. This is the report of analysis of the non-clinical pharmacology study of NV-CoV-2 (Polymer) and NV-CoV-2-R (Polymer encapsulated Remdesivir) in both infected and uninfected rats with SARS-CoV-2. Detection and quantification of NV-CoV-2-R in plasma samples was done by MS-HPLC chromatography analyses of precipitated plasma samples from rat subjects. O_LINV-CoV-2-R show RDV peak in MS-HPLC chromatography, whereas only NV-CoV-2 does not show any RDV-Peak, as expected. C_LIO_LINV-CoV-2 polymer encapsulation protects RDV in vivo from plasma-mediated catabolism. C_LIO_LIBody weight measurements of the normal (uninfected) rats after administration of the test materials (NV-CoV-2, and NV-CoV-2-R) show no toxic effects on them. C_LI Our platform technology based NV-387-encapsulated-RDV (NV-CoV-2-R) drug has a dual effect on coronaviruses. First, NV-CoV-2 itself as an antiviral regimen. Secondly, RDV is protected from plasma-mediated degradation in transit, rendering altogether the safest and an efficient regimen against COVID-19.

pharmacology and toxicology↗

bioRxiv2021

Nanoviricides Platform Technology based NV-387 polymer Protects Remdesivir from Plasma-Mediated Catabolism in vitro:Importance of its increased lifetime for in vivo action

As of today seven coronaviruses were identified to infect humans, out of which only 4 of them belongs to beta family of coronavirus, like HCoV-HKU1, SARS-CoV-2, MERS-CoV and SARS-CoV. SARS family of viruses were known to cause severe respiratory disease in humans. SARS-CoV-2 infection causes pandemic COVID-19 disease with high morbidity and mortality. Remdesivir (RDV) is the only antiviral drug so far approved for Covid-19 therapy by FDA. However its efficacy is limited in vivo due to its low stability in presence of Plasma. Here we show the stability of RDV encapsulated with our platform technology based polymer NV-387 (NV-CoV-2-R), in presence of Plasma in vitro in comparison to naked RDV when incubated in plasma. The potential use of this polymer in vivo will be discussed, here.

cell biology↗

bioRxiv2021

TRAF2, an innate immune sensor, reciprocally regulates mitophagy and inflammation to maintain cardiac myocyte homeostasis.

Mitochondrial damage triggers cell death signaling with catastrophic consequences in long-lived and irreplaceable cells, such as cardiac myocytes. Sensing of leaked mitochondrial DNA upon mitochondrial damage is also a potent trigger of inflammation. Whether the innate immune response pathways monitor mitochondrial damage in mitochondria-rich cardiac myocytes to prevent inflammation and cell death, remains unknown. TRAF2, an adaptor protein downstream of innate immune receptors, localizes to the mitochondria in the unstressed heart, with increased mitochondrial targeting in cardiomyopathic human hearts and after cardiac ischemia-reperfusion injury in mice. Inducible cardiomyocyte-specific deletion of TRAF2 in young adult mice impairs mitophagy with rapid decline in mitochondrial quality, upregulates TLR9 expression in cardiac myocytes, and results in inflammation and cell death manifesting as a fulminant cardiomyopathy. Preventing TLR9-mediated mitochondrial DNA sensing and resultant inflammation provides a short-term reprieve from cardiomyopathy, but persistence of damaged mitochondria results in long-term recrudescence. Restoration of wild-type TRAF2, but not the E3 ubiquitin ligase deficient mutant, improves mitochondrial quality and rescues cardiomyopathy to restore homeostasis. Thus, the innate immune response acts via TRAF2 as the first line of defense against mitochondrial damage by orchestrating homeostatic mitophagy to dampen myocardial inflammation and prevent cell death.

cell biology↗

bioRxiv2021

Single-cell transcriptome profiling reveals multicellular ecosystem of nucleus pulposus during degeneration progression

Degeneration of the nucleus pulposus (NP) is a major contributor to intervertebral disc degeneration (IVDD) and low back pain. However, the underlying molecular complexity and cellular heterogeneity remain poorly understood. Here, we first reported a comprehensive single-cell resolution transcriptional landscape of human NP. Six novel human nucleus pulposus cell (NPCs) populations were identified by distinct molecular signatures. The potential functional differences among NPC subpopulations were analyzed at the single-cell level. Predictive genes, transcriptional factors, and signal pathways with respect to degeneration grades were analyzed. We reported that fibroNPCs, one of our identified subpopulations, might be a population for NP regeneration. CD90+NPCs were observed to be progenitor cells in degenerative NP tissues. NP-infiltrating immune cells comprise a previously unrecognized diversity of cell types, including granulocytic myeloid-derived suppressor cells (G-MDSCs). We uncovered CD11b, OLR1, and CD24 as surface markers of NP-derived G-MDSCs. The G-MDSCs were also found to be enriched in mildly degenerated (grade I and II) NP tissues compared to severely degenerated (grade III and IV) NP tissues. Their immunosuppressive function and protective effects for NPCs were revealed. Collectively, this study revealed the NPC type complexity and phenotypic characteristics in NP, providing new insights and clues for IVDD treatment.

cell biology↗

bioRxiv2021

Apolipoprotein M attenuates doxorubicin cardiotoxicity by regulating transcription factor EB

ObjectivesDetermine the role of apolipoprotein M (ApoM) in anthracycline (Dox) cardiotoxicity. BackgroundApoM binds the cardioprotective sphingolipid sphingosine-1-phosphate (S1P). Circulating ApoM is inversely associated with mortality in human heart failure (HF). MethodsIn the Penn HF Study (PHFS), we tested the relationship between ApoM and mortality in a subset with anthracycline-induced cardiomyopathy. We measured ApoM in humans and mice treated with Dox and utilized hepatic ApoM transgenic (ApomTG), ApoM knockout (ApomKO), ApoM knock-in mice with impaired S1P binding, and S1P receptor 3 (S1PR3) knockout mice in Dox cardiotoxicity. We assayed autophagy in left ventricular tissue from anthracycline-induced HF patients versus donor controls. ResultsApoM was inversely associated with mortality in PHFS, and Dox reduced circulating ApoM in mice and breast cancer patients. ApomTG mice were protected from Dox-induced cardiac dysfunction and loss of left ventricular mass. ApomTG attenuated Dox-induced impairment in autophagic flux in vivo and accumulation of insoluble p62, which was also observed in the myocardium of patients with anthracycline-induced HF. In vehicle-treated mice, ApoM negatively regulated transcription factor EB (TFEB), a master regulator of autophagy and lysosomal biogenesis. The effect of ApoM on TFEB required both S1P binding and S1PR3. In the presence of Dox, ApoM preserved TFEB and cardiomyocyte lysosomal abundance assessed as lysosomal associated membrane protein 1 positive structures in vivo, while S1P mimetic pretreatment of cardiomyocytes prevented Dox-induced changes in lysosomal pH. ConclusionsApoM attenuates Dox cardiotoxicity via the autophagy-lysosome pathway. The association between ApoM and reduced mortality may be explained by its role in sustaining autophagy. HighlightsO_LICirculating ApoM is inversely associated with survival in human anthracycline-induced cardiomyopathy C_LIO_LIAnthracycline treatment reduces circulating ApoM in humans and mice C_LIO_LIIncreasing ApoM attenuates doxorubicin cardiotoxicity, lysosomal injury and preserves myocardial autophagic flux, but does not impact doxorubicin anti-neoplastic efficacy C_LIO_LIAutophagic impairment is characteristic of human anthracycline cardiomyopathy C_LI

pharmacology and toxicology↗