Coordinated initiation of DNA replication is essential to ensure efficient and timely DNA synthesis. Yet, molecular mechanism describing how replication initiation is coordinated in eukar-yotic cells is not completely understood. Herein, we present data demonstrating a novel feature of RNAs transcribed in the proximity of actively replicating gene loci. We show that RNAs aN-Choring ORC1 (ANCORs) to the histone variant H2A.Z are licensors of the DNA replication process. This ANCOR-H2A.Z interaction is essential for cells to initiate duplication of their ge-netic material. Widespread and locus-specific perturbations of these transcripts correlate with anomalous replication patterns and a notable loss of the H2A.Z replicative marker at the origin site. Collectively, we present a previously undescribed RNA-mediated mechanism that is associ-ated with the generation of active replication origins in eukaryotic cells. Our findings delineate a strategy to modulate the origins of replication in human cells at a local and global level, with potentially broad biomedical implications.

Increasing lifespans make health problems in the elderly such as opioid misuse a more prominent concern. Understanding the effects that opioids may have on the aged brain can help us address age-related concerns of opioid exposure. This study aimed to assess potential interactions between aging and opioid exposure. Three-month-old (young adult) and 19-month-old (aged) C57BL/6JN mice were assigned to either a morphine (3mg/kg, i.p.) or saline group. A conditioned placed preference (CPP) task was used to assess reward sensitivity, while rotarod and beam walk tests were used to assess sensorimotor coordination. To assess for potential age-dependent effects of morphine on gene expression, we performed RNA sequencing in the prefrontal cortex (PFC). We found that morphine induced CPP in both age groups. Our results indicate impaired motor coordination in aged mice; however, morphine did not significantly affect motor coordination in either age group, although a trend toward an increased number of slips was observed in morphine-treated aged mice. Transcriptomic analysis revealed more robust effects of morphine on gene expression in the aged brain compared to the young brain. Interestingly, we found limited overlap between morphine-regulated genes in young and old mice, suggesting that the molecular effects of morphine are age-dependent. Taken together, while we found no significant interactions between morphine (at the tested dose) and aging in the behavioral assays, morphine caused age-dependent gene expression changes. Our findings suggest that age should be considered when prescribing opioids and that age-specific therapeutics may help address opioid use disorder in the elderly.

Abstract Liver disease is a major global health concern, claiming approximately 2 million lives worldwide annually, yet curative treatments remain elusive. In our study, we aimed to investigate the role of microRNA-21-5p (miR-21) in metabolic dysfunction-associated steatotic liver disease (previously NAFLD), metabolic-associated steatohepatitis (previously NASH), and hepatocellular carcinoma (HCC) within the context of a Western high-fat diet (HFD) and offering potential therapeutic insights. We found that reduced miR-21 levels correlated with liver disease progression in WT mice fed on HFD, while miR-21 knockout mice showed exacerbated metabolic dysfunction, including obesity, hepatomegaly, hyperglycemia, insulin resistance, steatosis, fibrosis, and HCC. Our study reveals that miR-21 plays a protective role in metabolic syndrome and in the progression of liver disease to cancer. miR-21 directly targets Transforming growth factor beta-induced (Tgfbi), a gene also known to be significantly upregulated and a potential oncogene in HCC. Further, our study showed that intervention with the administration of a miR-21 mimic in WT livers in HFD conditions effectively improves insulin sensitivity, steatosis, fibrosis, tumor burden, as well as Tgfbi expression. These findings indicate that miR-21 could serve as an effective strategy to delay or prevent liver disease in high-fat-diet environments. Citation Format: Urmila Jagtap, Anan Quan, Yuho Ono, Jonathan Lee, Kylie A. Shen, Sergei Manakov, Gyongyi Szabo, Imad Nasser, Frank J. Slack. miR-21: A therapeutic target that delays severe liver disease and hepatocellular carcinoma under high-fat-diet conditions [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5689.

Severe COVID-19 leads to widespread transcriptomic changes in the human brain, mimicking diminished cognitive performance. As long noncoding RNAs (lncRNAs) play crucial roles in the regulation of gene expression, identification of the lncRNAs differentially expressed upon COVID-19 may nominate key regulatory nodes underpinning cognitive changes. Here we identify hundreds of lncRNAs differentially expressed in the brains of COVID-19 patients relative to uninfected age/sex-matched controls, many of which are associated with decreased cognitive performance and inflammatory cytokine response. Our analyses reveal pervasive transcriptomic changes in lncRNA expression upon severe COVID-19, which may serve as key regulators of neurocognitive changes in the brain.

Liver disease, including hepatocellular carcinoma (HCC), is a major global health concern, claiming approximately 2 million lives worldwide annually, yet curative treatments remain elusive. In this study, we aimed to investigate the role of microRNA-21-5p (miR-21) in metabolic dysfunction-associated steatotic liver disease (previously NAFLD), metabolic-associated steatohepatitis (previously NASH), and HCC within the context of a Western high-fat diet, without additional choline (HFD) and offering potential therapeutic insights. We found that reduced miR-21 levels correlated with liver disease progression in WT mice fed on HFD, while miR-21 knockout mice showed exacerbated metabolic dysfunction, including obesity, hepatomegaly, hyperglycemia, insulin resistance, steatosis, fibrosis, and HCC. Our study reveals that miR-21 plays a protective role in metabolic syndrome and in the progression of liver disease to cancer. MiR-21 directly targets Transforming growth factor beta-induced (Tgfbi), a gene also known to be significantly upregulated and a potential oncogene in HCC. Further, our study showed that intervention with the administration of a miR-21 mimic in WT livers effectively improves insulin sensitivity, steatosis, fibrosis, Tgfbi expression and tumor burden in HFD conditions. These findings indicate that miR-21 could serve as an effective strategy to delay or prevent liver disease in high-fat-diet environments.

COVID-19 remains a significant public health threat due to the ability of SARS-CoV-2 variants to evade the immune system and cause breakthrough infections. Although pathogenic coronaviruses such as SARS-CoV-2 and MERS-CoV lead to severe respiratory infections, how these viruses affect the chromatin proteomic composition upon infection remains largely uncharacterized. Here we used our recently developed integrative DNA And Protein Tagging (iDAPT) methodology to identify changes in host chromatin accessibility states and chromatin proteomic composition upon infection with pathogenic coronaviruses. SARS-CoV-2 infection induces TP53 stabilization on chromatin, which contributes to its host cytopathic effect. We mapped this TP53 stabilization to the SARS-CoV-2 spike and its propensity to form syncytia, a consequence of cell-cell fusion. Differences in SARS-CoV-2 spike variant-induced syncytia formation modify chromatin accessibility, cellular senescence, and inflammatory cytokine release via TP53. Our findings suggest that differences in syncytia formation alter senescence-associated inflammation, which varies among SARS-CoV-2 variants.

Several microRNAs have emerged as regulators of pathways that control aging. For example, miR-228 is required for normal lifespan and dietary restriction (DR) mediated longevity through interaction with PHA-4 and SKN-1 transcription factors in Caenorhabditis elegans. miR-229,64,65, and 66, a cluster of microRNAs located adjacent to each other on chromosome III, are in the same family as miR-228, albeit with slight differences in the miR-228 seed sequence. We demonstrate that, in contrast to the anti-longevity role of miR-228, the miR-229-66 cluster is required for normal C. elegans lifespan and for the longevity observed in mir-228 mutants. miR-229-66 is also critical for lifespan extension observed under DR and reduced insulin signaling (IIS) and by constitutive nuclear SKN-1. Both DR and low-IIS upregulate the expression of the miRNA cluster, which is dependent on transcription factors PHA-4, SKN-1, and DAF-16. In turn, the expression of SKN-1 and DAF-16 requires mir-229,64,65,66. miR-229-66 targets the odd-skipped-related transcription factor, odd-2 to regulate lifespan. Knockdown of odd-2 increases lifespan, suppresses the short lifespan of mir-229,64,65,66(nDf63) III mutants, and alters levels of SKN-1 in the ASI neurons. Together with SKN-1, the miRNA cluster also indirectly regulates several genes in the xenobiotic detoxification pathway which increases wild-type lifespan and significantly rescues the short lifespan of mir-229,64,65,66(nDf63) III mutants. Thus, by interacting with SKN-1, miR-229-66 transduces the effects of DR and low-IIS in lifespan extension in C. elegans. Given that this pathway is conserved, it is possible that a similar mechanism regulates aging in more complex organisms.

Coronavirus disease 2019 (COVID-19) is predominantly an acute respiratory disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and remains a significant threat to public health. COVID-19 is accompanied by neurological symptoms and cognitive decline, but the molecular mechanisms underlying this effect remain unclear. As aging induces distinct molecular signatures in the brain associated with cognitive decline in healthy populations, we hypothesized that COVID-19 may induce molecular signatures of aging. Here, we performed whole transcriptomic analysis of human frontal cortex, a critical area for cognitive function, in 12 COVID-19 cases and age- and sex-matched uninfected controls. COVID-19 induces profound changes in gene expression, despite the absence of detectable virus in brain tissue. Pathway analysis shows downregulation of genes involved in synaptic function and cognition and upregulation of genes involved in immune processes. Comparison with five independent transcriptomic datasets of aging human frontal cortex reveals striking similarities between aged individuals and severe COVID-19 patients. Critically, individuals below 65 years of age exhibit profound transcriptomic changes not observed among older individuals in our patient cohort. Our data indicate that severe COVID-19 induces molecular signatures of aging in the human brain and emphasize the value of neurological follow-up in recovered individuals.

The zinc finger transcription factor SALL4 is highly expressed in embryonic stem cells, downregulated in most adult tissues, but reactivated in many aggressive cancers. This unique expression pattern makes SALL4 an attractive therapeutic target. However, whether SALL4 binds DNA directly to regulate gene expression is unclear, and many of its targets in cancer cells remain elusive. Here, through an unbiased screen of protein binding microarray (PBM) and cleavage under targets and release using nuclease (CUT&RUN) experiments, we identify and validate the DNA binding domain of SALL4 and its consensus binding sequence. Combined with RNA sequencing (RNA-seq) analyses after SALL4 knockdown, we discover hundreds of new SALL4 target genes that it directly regulates in aggressive liver cancer cells, including genes encoding a family of histone 3 lysine 9-specific demethylases (KDMs). Taken together, these results elucidate the mechanism of SALL4 DNA binding and reveal pathways and molecules to target in SALL4-dependent tumors.

The architecture of chromatin regulates eukaryotic cell states by controlling transcription factor access to sites of gene regulation. Here we describe a dual transposase-peroxidase approach, integrative DNA and protein tagging (iDAPT), which detects both DNA (iDAPT-seq) and protein (iDAPT-MS) associated with accessible regions of chromatin. In addition to direct identification of bound transcription factors, iDAPT enables the inference of their gene regulatory networks, protein interactors and regulation of chromatin accessibility. We applied iDAPT to profile the epigenomic consequences of granulocytic differentiation of acute promyelocytic leukemia, yielding previously undescribed mechanistic insights. Our findings demonstrate the power of iDAPT as a platform for studying the dynamic epigenomic landscapes and their transcription factor components associated with biological phenomena and disease.

Chromosomal rearrangements can generate genetic fusions composed of two distinct gene sequences, many of which have been implicated in tumorigenesis and progression. Our study proposes a model whereby oncogenic gene fusions frequently alter the protein stability of the resulting fusion products, via exchanging protein degradation signal (degron) between gene sequences. Computational analyses of The Cancer Genome Atlas (TCGA) identify 2,406 cases of degron exchange events and reveal an enrichment of oncogene stabilization due to loss of degrons from fusion. Furthermore, we identify and experimentally validate that some recurrent fusions, such as BCR-ABL, CCDC6-RET and PML-RARA fusions, perturb protein stability by exchanging internal degrons. Likewise, we also validate that EGFR or RAF1 fusions can be stabilized by losing a computationally-predicted C-terminal degron. Thus, complementary to enhanced oncogene transcription via promoter swapping, our model of degron loss illustrates another general mechanism for recurrent fusion proteins in driving tumorigenesis.

Abstract Clonal Hematopoiesis of Indeterminate Potential (CHIP) is the age-associated acquisition of detectable stem cell mutations, known to predispose patients towards Acute Myeloid Leukemia (AML) and cardiovascular disease. While progression to AML is believed arise from the acquisition of additional clonal mutations, cardiovascular disease is thought to be a consequence of aberrant pro-inflammatory signaling[1]. Here, we show that the development of genetic aberrations seen in CHIP disorders can profoundly shift the cellular composition of multiple hematopoietic microenvironments. TP53 is the most frequently mutated gene in human cancers and is one of several frequently mutated genes in CHIP and AML[2]. To model loss of Trp53 in a subset of cells of the hematopoietic system, we generated mixed bone marrow chimeras by transplantation of either Trp53−/− or wild type bone marrow mononuclear cells (BMNCs) in conjunction with congenic wild type cells. Following reconstitution, we observed increased levels of wild type T cells in mice transplanted with Trp53−/− BMNCs. Interestingly, both CD4+ and CD8+ T cells showed increases in naïve T cell subsets while only CD4+ T cells showed an increase in effector/effector memory T cell subsets. In line with these results, we observed a short-term decrease in the number of effector/effector memory T cells in the wild type compartment of Trp53−/− chimeras, indicating delayed effector T cell formation. To determine if these alterations were mirrored in the leukemic setting, we next generated MLL-AF9 and Trp53−/−;NrasG12D leukemia, faithfully modeling the intrapatient heterogeneity which occurs as a result of CHIP progressing to AML [2] by transplanting both Trp53−/− and Trp53−/−;NrasG12D KSL into sublethally irradiated primary recipients. While the bone marrow of Trp53−/−;NrasG12D leukemia showed the presence of both invading T and B lymphocytes, MLL-AF9 showed a near complete absence of lymphocytes, reminiscent of ‘immune-infiltrated' and ‘immune-desert' phenotypes seen in solid tumors. These data clearly demonstrate a cell-extrinsic effect of partial Trp53 loss in the hematopoietic system in the absence of a leukemic clone, which could potentially serve to explain the paradoxical observation that immunoediting does not occur in a mouse model of MLL-ENL[3]. Thus, CHIP may constitute a novel and leukemia-specific means of immunoediting via diverse alteration of the hematopoietic microenvironment prior to the development of malignancy. 1. Jaiswal, S., et al., Clonal Hematopoiesis and Risk of Atherosclerotic Cardiovascular Disease. New England Journal of Medicine, 2017. 377(2): p. 111-121. 2. Steensma, D.P., et al., Clonal hematopoiesis of indeterminate potential and its distinction from myelodysplastic syndromes. Blood, 2015. 126(1): p. 9-16. 3. Dudenhöffer-Pfeifer, M. and D. Bryder, Immunoediting is not a primary transformation event in a murine model of MLL-ENL AML. Life Science Alliance, 2018. 1(4): p. e201800079. Citation Format: Ryan R. Posey, Lourdes M. Mendez, Jonathan D. Lee, John G. Clohessy, Pier Paolo Pandolfi. CHIP and AML mutations dictate the composition of hematopoietic microenvironments [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1694.

TP53 is the most frequently mutated gene in human cancers. In Acute Myeloid Leukemia (AML) and Clonal Hematopoiesis of Indeterminate Potential (CHIP), it is one of several recurrent genetic alterations. Despite multiple recent therapeutic advances for AML, TP53 mutated AML is associated with resistance to currently approved therapies and thus, a very poor prognosis. Emerging evidence suggests that mutations in TP53 may be a predictor of positive response to immunotherapy. To model cell - extrinsic consequences of hematopoietic p53 loss, we generated bone marrow chimeric mice bearing p53 -/- and congenic wild type cells. Following reconstitution, we observed increased levels of wild type CD8+ and CD4+ T cells in mice transplanted with p53 -/- hematopoietic cells compared to controls. In addition, we observed a change in the frequency of T cell subsets in p53 -/- chimeras including an increase in Tregs. To determine if these alterations were mirrored in the leukemic setting, we next generated p53 -/- ; nRas G12D leukemia. While the bone marrow of p53 -/- ; nRas G12D leukemia showed the presence of both T and B lymphocytes, MLL-AF9 showed a near complete absence of lymphocytes, akin to ‘immune-infiltrated’ and ‘immune-desert’ phenotypes seen in solid tumors. These data clearly demonstrate a causal cell-extrinsic effect of hematopoietic p53 loss on the immune system, both in the context of leukemia and preleukemic states. Modeling AML genetics in murine models serves as a powerful tool to define the association between genetic drivers and immune subtypes of AML towards precise patient stratification critical for the application of emerging targeted and immune therapies. Statement of Significance TP53 mutations are frequent in both AML and CHIP, and are associated with both resistance to therapy as well as very poor prognosis. We provide evidence to investigate the immunotherapy as a treatment option for this subgroup of AML.

Activation of tumor suppressors for the treatment of human cancer has been a long sought, yet elusive, strategy. PTEN is a critical tumor suppressive phosphatase that is active in its dimer configuration at the plasma membrane. Polyubiquitination by the ubiquitin E3 ligase WWP1 (WW domain-containing ubiquitin E3 ligase 1) suppressed the dimerization, membrane recruitment, and function of PTEN. Either genetic ablation or pharmacological inhibition of WWP1 triggered PTEN reactivation and unleashed tumor suppressive activity. WWP1 appears to be a direct MYC (MYC proto-oncogene) target gene and was critical for MYC-driven tumorigenesis. We identified indole-3-carbinol, a compound found in cruciferous vegetables, as a natural and potent WWP1 inhibitor. Thus, our findings unravel a potential therapeutic strategy for cancer prevention and treatment through PTEN reactivation.

RNA modifications are emerging as key determinants of gene expression. However, compelling genetic demonstrations of their relevance to human disease are lacking. Here, we link ribosomal RNA 2'-O-methylation (2'-O-Me) to the etiology of dyskeratosis congenita. We identify nucleophosmin (NPM1) as an essential regulator of 2'-O-Me on rRNA by directly binding C/D box small nucleolar RNAs, thereby modulating translation. We demonstrate the importance of 2'-O-Me-regulated translation for cellular growth, differentiation and hematopoietic stem cell maintenance, and show that Npm1 inactivation in adult hematopoietic stem cells results in bone marrow failure. We identify NPM1 germline mutations in patients with dyskeratosis congenita presenting with bone marrow failure and demonstrate that they are deficient in small nucleolar RNA binding. Mice harboring a dyskeratosis congenita germline Npm1 mutation recapitulate both hematological and nonhematological features of dyskeratosis congenita. Thus, our findings indicate that impaired 2'-O-Me can be etiological to human disease.

Although targeted therapies have proven effective and even curative in human leukaemia, resistance often ensues. IDH enzymes are mutated in ~20% of human AML, with targeted therapies under clinical evaluation. We here characterize leukaemia evolution from mutant IDH2 (mIDH2)-dependence to independence identifying key targetable vulnerabilities of mIDH2 leukaemia that are retained during evolution and progression from early to late stages. Mechanistically, we find that mIDH2 leukaemia are metastable and vulnerable at two distinct levels. On the one hand, they are characterized by oxidative and genotoxic stress, in spite of increased 1-carbon metabolism and glutathione levels. On the other hand, mIDH2 leukaemia display inhibition of LSD1 and a resulting transcriptional signature of all-trans retinoic acid (ATRA) sensitization, in spite of a state of suppressed ATRA signalling due to increased levels of PIN1. We further identify GSH/ROS and PIN1/LSD1 as critical nodes for leukaemia maintenance and the combination of ATRA and arsenic trioxide (ATO) as a key therapeutic modality to target these vulnerabilities. Strikingly, we demonstrate that the combination of ATRA and ATO proves to be a powerfully synergistic and effective therapy in a number of mouse and human mIDH1/2 leukemic models. Thus, our findings pave the way towards the treatment of a sizable fraction of human AMLs through targeted APL-like combinatorial therapies.

Resistance to chemotherapy plays a significant role in cancer mortality. To identify genetic units affecting sensitivity to cytarabine, the mainstay of treatment for acute myeloid leukemia (AML), we developed a comprehensive and integrated genome-wide platform based on a dual protein-coding and non-coding integrated CRISPRa screening (DICaS). Putative resistance genes were initially identified using pharmacogenetic data from 760 human pan-cancer cell lines. Subsequently, genome scale functional characterization of both coding and long non-coding RNA (lncRNA) genes by CRISPR activation was performed. For lncRNA functional assessment, we developed a CRISPR activation of lncRNA (CaLR) strategy, targeting 14,701 lncRNA genes. Computational and functional analysis identified novel cell-cycle, survival/apoptosis, and cancer signaling genes. Furthermore, transcriptional activation of the GAS6-AS2 lncRNA, identified in our analysis, leads to hyperactivation of the GAS6/TAM pathway, a resistance mechanism in multiple cancers including AML. Thus, DICaS represents a novel and powerful approach to identify integrated coding and non-coding pathways of therapeutic relevance.

Coronary artery disease (CAD) is the leading cause of mortality and morbidity, driven by both genetic and environmental risk factors. Meta-analyses of genome-wide association studies have identified >150 loci associated with CAD and myocardial infarction susceptibility in humans. A majority of these variants reside in non-coding regions and are co-inherited with hundreds of candidate regulatory variants, presenting a challenge to elucidate their functions. Herein, we use integrative genomic, epigenomic and transcriptomic profiling of perturbed human coronary artery smooth muscle cells and tissues to begin to identify causal regulatory variation and mechanisms responsible for CAD associations. Using these genome-wide maps, we prioritize 64 candidate variants and perform allele-specific binding and expression analyses at seven top candidate loci: 9p21.3, SMAD3 , PDGFD , IL6R , BMP1 , CCDC97 / TGFB1 and LMOD1 . We validate our findings in expression quantitative trait loci cohorts, which together reveal new links between CAD associations and regulatory function in the appropriate disease context.

Percutaneous interventions including balloon angioplasty and stenting have been used to restore blood flow in vessels with occlusive vascular disease. While these therapies lead to the rapid restoration of blood flow, these technologies remain limited by restenosis in the case of bare metal stents and angioplasty, or reduced healing and possibly enhanced risk of thrombosis in the case of drug eluting stents. A key pathophysiological mechanism in the formation of restenosis is intimal hyperplasia caused by the activation of vascular smooth muscle cells and inflammation due to arterial stretch and injury. Surgeries that induce arterial injury in genetically modified mice are useful for the mechanistic study of the vascular response to injury but are often technically challenging to perform in mouse models due to the their small size and lack of appropriate sized devices. We describe two approaches for a surgical technique that induces endothelial denudation and arterial stretch in the femoral artery of mice to produce robust neointimal hyperplasia. The first approach creates an arteriotomy in the muscular branch of the femoral artery to obtain vascular access. Following wire injury this arterial branch is ligated to close the arteriotomy. A second approach creates an arteriotomy in the main femoral artery that is later closed through localized cautery. This method allows for vascular access through a larger vessel and, consequently, provides a less technically demanding procedure that can be used in smaller mice. Following either method of arterial injury, a degradable drug delivery patch can be placed over or around the injured artery to deliver therapeutic agents.

Introduction: Heart disease is currently the most common cause of death in the United States. In 2010 alone, over 375,000 people died of coronary heart disease, of which over 120,000 were from myocardial infarction. Due to technical challenges associated with current techniques, profiling epigenome changes due to myocardial infarction has been limited. We have optimized an assay for transposase-accessible chromatin with sequencing (ATAC-seq) protocol that circumvents these challenges and works well with frozen tissue. Hypothesis: We assessed the hypothesis that ATAC-seq would enable the identification of novel chromatin remodeling and transcription factor binding events in a murine model of cardiac ischemia. Methods: Six 10 ± 2 week old C57BL/6J mice were paired by same gender, age, and litter, and mice from these pairs were selected for either mid left anterior descending artery ligation or sham surgery, both for 30 minutes. Successful ligation was confirmed by blanching of the tissue and representative electrocardiography changes. We performed our ATAC-seq protocol on left ventricular tissues, and regions of open chromatin were determined using the Hotspot algorithm at a false detection rate of 0.5%. Gene ontology was performed with the Genomic Regions Enrichment of Annotations Tool (GREAT), and motif discovery was performed with the Multiple Em for Motif Elicitation (MEME) Suite. Results: From stringent overlap criteria were obtained 159 loci that became “open” due to ischemia and 782 loci that became “closed”. Downregulation of growth and signaling processes was determined by GREAT. MEME strongly implicated the dissociation of CCCTC-binding Factor (CTCF) due to ischemia (MEME E-score = 8.10e-235; motif identification p -value = 1.88e-18; 262/782 of “closed” loci). CTCF ChIP-seq data and footprint analysis enabled the further identification of a robust set of 189 CTCF differential binding events. Conclusions: ATAC-seq was able to identify widespread chromatin remodeling due to cardiac ischemia alone. We identified a robust set of 189 gene loci from which CTCF binding is attenuated in response to this disease state. To our knowledge, this represents the first study that has examined chromatin accessibility changes in the setting of cardiac ischemia.