Publications by authors named "Maria Fasolino"

20 Publications

  • Page 1 of 1

Single-cell multi-omics analysis of human pancreatic islets reveals novel cellular states in type 1 diabetes.

Nat Metab 2022 Feb 28;4(2):284-299. Epub 2022 Feb 28.

Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA.

Type 1 diabetes (T1D) is an autoimmune disease in which immune cells destroy insulin-producing beta cells. The aetiology of this complex disease is dependent on the interplay of multiple heterogeneous cell types in the pancreatic environment. Here, we provide a single-cell atlas of pancreatic islets of 24 T1D, autoantibody-positive and nondiabetic organ donors across multiple quantitative modalities including ~80,000 cells using single-cell transcriptomics, ~7,000,000 cells using cytometry by time of flight and ~1,000,000 cells using in situ imaging mass cytometry. We develop an advanced integrative analytical strategy to assess pancreatic islets and identify canonical cell types. We show that a subset of exocrine ductal cells acquires a signature of tolerogenic dendritic cells in an apparent attempt at immune suppression in T1D donors. Our multimodal analyses delineate cell types and processes that may contribute to T1D immunopathogenesis and provide an integrative procedure for exploration and discovery of human pancreatic function.
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http://dx.doi.org/10.1038/s42255-022-00531-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8938904PMC
February 2022

BET bromodomain protein inhibition reverses chimeric antigen receptor extinction and reinvigorates exhausted T cells in chronic lymphocytic leukemia.

J Clin Invest 2021 08;131(16)

Center for Cellular Immunotherapies.

Chimeric antigen receptor (CAR) T cells have induced remarkable antitumor responses in B cell malignancies. Some patients do not respond because of T cell deficiencies that hamper the expansion, persistence, and effector function of these cells. We used longitudinal immune profiling to identify phenotypic and pharmacodynamic changes in CD19-directed CAR T cells in patients with chronic lymphocytic leukemia (CLL). CAR expression maintenance was also investigated because this can affect response durability. CAR T cell failure was accompanied by preexisting T cell-intrinsic defects or dysfunction acquired after infusion. In a small subset of patients, CAR silencing was observed coincident with leukemia relapse. Using a small molecule inhibitor, we demonstrated that the bromodomain and extra-terminal (BET) family of chromatin adapters plays a role in downregulating CAR expression. BET protein blockade also ameliorated CAR T cell exhaustion as manifested by inhibitory receptor reduction, enhanced metabolic fitness, increased proliferative capacity, and enriched transcriptomic signatures of T cell reinvigoration. BET inhibition decreased levels of the TET2 methylcytosine dioxygenase, and forced expression of the TET2 catalytic domain eliminated the potency-enhancing effects of BET protein targeting in CAR T cells, providing a mechanism linking BET proteins and T cell dysfunction. Thus, modulating BET epigenetic readers may improve the efficacy of cell-based immunotherapies.
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http://dx.doi.org/10.1172/JCI145459DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8363276PMC
August 2021

Exome-wide evaluation of rare coding variants using electronic health records identifies new gene-phenotype associations.

Nat Med 2021 01 11;27(1):66-72. Epub 2021 Jan 11.

Division of Cardiothoracic Surgery, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, TX, USA.

The clinical impact of rare loss-of-function variants has yet to be determined for most genes. Integration of DNA sequencing data with electronic health records (EHRs) could enhance our understanding of the contribution of rare genetic variation to human disease. By leveraging 10,900 whole-exome sequences linked to EHR data in the Penn Medicine Biobank, we addressed the association of the cumulative effects of rare predicted loss-of-function variants for each individual gene on human disease on an exome-wide scale, as assessed using a set of diverse EHR phenotypes. After discovering 97 genes with exome-by-phenome-wide significant phenotype associations (P < 10), we replicated 26 of these in the Penn Medicine Biobank, as well as in three other medical biobanks and the population-based UK Biobank. Of these 26 genes, five had associations that have been previously reported and represented positive controls, whereas 21 had phenotype associations not previously reported, among which were genes implicated in glaucoma, aortic ectasia, diabetes mellitus, muscular dystrophy and hearing loss. These findings show the value of aggregating rare predicted loss-of-function variants into 'gene burdens' for identifying new gene-disease associations using EHR phenotypes in a medical biobank. We suggest that application of this approach to even larger numbers of individuals will provide the statistical power required to uncover unexplored relationships between rare genetic variation and disease phenotypes.
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http://dx.doi.org/10.1038/s41591-020-1133-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8775355PMC
January 2021

SARS-CoV-2 Cell Entry Factors ACE2 and TMPRSS2 Are Expressed in the Microvasculature and Ducts of Human Pancreas but Are Not Enriched in β Cells.

Cell Metab 2020 12 13;32(6):1028-1040.e4. Epub 2020 Nov 13.

Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; VA Tennessee Valley Healthcare System, Nashville, TN 37212, USA; Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA. Electronic address:

Isolated reports of new-onset diabetes in individuals with COVID-19 have led to the hypothesis that SARS-CoV-2 is directly cytotoxic to pancreatic islet β cells. This would require binding and entry of SARS-CoV-2 into β cells via co-expression of its canonical cell entry factors, angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2); however, their expression in human pancreas has not been clearly defined. We analyzed six transcriptional datasets of primary human islet cells and found that ACE2 and TMPRSS2 were not co-expressed in single β cells. In pancreatic sections, ACE2 and TMPRSS2 protein was not detected in β cells from donors with and without diabetes. Instead, ACE2 protein was expressed in islet and exocrine tissue microvasculature and in a subset of pancreatic ducts, whereas TMPRSS2 protein was restricted to ductal cells. These findings reduce the likelihood that SARS-CoV-2 directly infects β cells in vivo through ACE2 and TMPRSS2.
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http://dx.doi.org/10.1016/j.cmet.2020.11.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7664344PMC
December 2020

SARS-CoV-2 Cell Entry Factors ACE2 and TMPRSS2 are Expressed in the Pancreas but are Not Enriched in Islet Endocrine Cells.

bioRxiv 2020 Oct 20. Epub 2020 Oct 20.

Reports of new-onset diabetes and diabetic ketoacidosis in individuals with COVID-19 have led to the hypothesis that SARS-CoV-2, the virus that causes COVID-19, is directly cytotoxic to pancreatic islet β cells. This would require binding and entry of SARS-CoV-2 into host β cells via cell surface co-expression of ACE2 and TMPRSS2, the putative receptor and effector protease, respectively. To define ACE2 and TMPRSS2 expression in the human pancreas, we examined six transcriptional datasets from primary human islet cells and assessed protein expression by immunofluorescence in pancreata from donors with and without diabetes. and transcripts were low or undetectable in pancreatic islet endocrine cells as determined by bulk or single cell RNA sequencing, and neither protein was detected in α or β cells from these donors. Instead, ACE2 protein was expressed in the islet and exocrine tissue microvasculature and also found in a subset of pancreatic ducts, whereas TMPRSS2 protein was restricted to ductal cells. The absence of significant ACE2 and TMPRSS2 co-expression in islet endocrine cells reduces the likelihood that SARS-CoV-2 directly infects pancreatic islet β cells through these cell entry proteins.
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http://dx.doi.org/10.1101/2020.08.31.275719DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7587777PMC
October 2020

TooManyCells identifies and visualizes relationships of single-cell clades.

Nat Methods 2020 04 2;17(4):405-413. Epub 2020 Mar 2.

Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA.

Identifying and visualizing transcriptionally similar cells is instrumental for accurate exploration of the cellular diversity revealed by single-cell transcriptomics. However, widely used clustering and visualization algorithms produce a fixed number of cell clusters. A fixed clustering 'resolution' hampers our ability to identify and visualize echelons of cell states. We developed TooManyCells, a suite of graph-based algorithms for efficient and unbiased identification and visualization of cell clades. TooManyCells introduces a visualization model built on a concept intentionally orthogonal to dimensionality-reduction methods. TooManyCells is also equipped with an efficient matrix-free divisive hierarchical spectral clustering different from prevalent single-resolution clustering methods. TooManyCells enables multiresolution and multifaceted exploration of single-cell clades. An advantage of this paradigm is the immediate detection of rare and common populations that outperforms popular clustering and visualization algorithms, as demonstrated using existing single-cell transcriptomic data sets and new data modeling drug-resistance acquisition in leukemic T cells.
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http://dx.doi.org/10.1038/s41592-020-0748-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7439807PMC
April 2020

Joint profiling of chromatin accessibility and CAR-T integration site analysis at population and single-cell levels.

Proc Natl Acad Sci U S A 2020 03 24;117(10):5442-5452. Epub 2020 Feb 24.

Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104;

Chimeric antigen receptor (CAR)-T immunotherapy has yielded impressive results in several B cell malignancies, establishing itself as a powerful means to redirect the natural properties of T lymphocytes. In this strategy, the T cell genome is modified by the integration of lentiviral vectors encoding CAR that direct tumor cell killing. However, this therapeutic approach is often limited by the extent of CAR-T cell expansion in vivo. A major outstanding question is whether or not CAR-T integration itself enhances the proliferative competence of individual T cells by rewiring their regulatory landscape. To address this question, it is critical to define the identity of an individual CAR-T cell and simultaneously chart where the CAR-T vector integrates into the genome. Here, we report the development of a method called EpiVIA (https://github.com/VahediLab/epiVIA) for the joint profiling of the chromatin accessibility and lentiviral integration site analysis at the population and single-cell levels. We validate our technique in clonal cells with previously defined integration sites and further demonstrate the ability to measure lentiviral integration sites and chromatin accessibility of host and viral genomes at the single-cell resolution in CAR-T cells. We anticipate that EpiVIA will enable the single-cell deconstruction of gene regulation during CAR-T therapy, leading to the discovery of cellular factors associated with durable treatment.
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http://dx.doi.org/10.1073/pnas.1919259117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7071901PMC
March 2020

Genetic Variation in Type 1 Diabetes Reconfigures the 3D Chromatin Organization of T Cells and Alters Gene Expression.

Immunity 2020 02 11;52(2):257-274.e11. Epub 2020 Feb 11.

Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Epigenetics Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Institute for Diabetes, Obesity and Metabolism, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Abramson Family Cancer Research Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; The Human Pancreas Analysis Program, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA, https://hpap.pmacs.upenn.edu/. Electronic address:

Genetics is a major determinant of susceptibility to autoimmune disorders. Here, we examined whether genome organization provides resilience or susceptibility to sequence variations, and how this would contribute to the molecular etiology of an autoimmune disease. We generated high-resolution maps of linear and 3D genome organization in thymocytes of NOD mice, a model of type 1 diabetes (T1D), and the diabetes-resistant C57BL/6 mice. Multi-enhancer interactions formed at genomic regions harboring genes with prominent roles in T cell development in both strains. However, diabetes risk-conferring loci coalesced enhancers and promoters in NOD, but not C57BL/6 thymocytes. 3D genome mapping of NODxC57BL/6 F1 thymocytes revealed that genomic misfolding in NOD mice is mediated in cis. Moreover, immune cells infiltrating the pancreas of humans with T1D exhibited increased expression of genes located on misfolded loci in mice. Thus, genetic variation leads to altered 3D chromatin architecture and associated changes in gene expression that may underlie autoimmune pathology.
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http://dx.doi.org/10.1016/j.immuni.2020.01.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7152927PMC
February 2020

A mass spectrometry-based assay using metabolic labeling to rapidly monitor chromatin accessibility of modified histone proteins.

Sci Rep 2019 09 20;9(1):13613. Epub 2019 Sep 20.

Epigenetics Institute, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.

Histone post-translational modifications (PTMs) contribute to chromatin accessibility due to their chemical properties and their ability to recruit enzymes responsible for DNA readout and chromatin remodeling. To date, more than 400 different histone PTMs and thousands of combinations of PTMs have been identified, the vast majority with still unknown biological function. Identification and quantification of histone PTMs has become routine in mass spectrometry (MS) but, since raising antibodies for each PTM in a study can be prohibitive, lots of potential is lost from MS datasets when uncharacterized PTMs are found to be significantly regulated. We developed an assay that uses metabolic labeling and MS to associate chromatin accessibility with histone PTMs and their combinations. The labeling is achieved by spiking in the cell media a 5x concentration of stable isotope labeled arginine and allow cells to grow for at least one cell cycle. We quantified the labeling incorporation of about 200 histone peptides with a proteomics workflow, and we confirmed that peptides carrying PTMs with extensively characterized roles in active transcription or gene silencing were in highly or poorly labeled forms, respectively. Data were further validated using next-generation sequencing to assess the transcription rate of chromatin regions modified with five selected PTMs. Furthermore, we quantified the labeling rate of peptides carrying co-existing PTMs, proving that this method is suitable for combinatorial PTMs. We focus on the abundant bivalent mark H3K27me3K36me2, showing that H3K27me3 dominantly represses histone swapping rate even in the presence of the more permissive PTM H3K36me2. Together, we envision this method will help to generate hypotheses regarding histone PTM functions and, potentially, elucidate the role of combinatorial histone codes.
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http://dx.doi.org/10.1038/s41598-019-49894-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6754405PMC
September 2019

Oncogenic Notch Promotes Long-Range Regulatory Interactions within Hyperconnected 3D Cliques.

Mol Cell 2019 03 7;73(6):1174-1190.e12. Epub 2019 Feb 7.

Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Institute for Biomedical Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Cancer Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA. Electronic address:

Chromatin loops enable transcription-factor-bound distal enhancers to interact with their target promoters to regulate transcriptional programs. Although developmental transcription factors such as active forms of Notch can directly stimulate transcription by activating enhancers, the effect of their oncogenic subversion on the 3D organization of cancer genomes is largely undetermined. By mapping chromatin looping genome-wide in Notch-dependent triple-negative breast cancer and B cell lymphoma, we show that beyond the well-characterized role of Notch as an activator of distal enhancers, Notch regulates its direct target genes by instructing enhancer repositioning. Moreover, a large fraction of Notch-instructed regulatory loops form highly interacting enhancer and promoter spatial clusters termed "3D cliques." Loss- and gain-of-function experiments show that Notch preferentially targets hyperconnected 3D cliques that regulate the expression of crucial proto-oncogenes. Our observations suggest that oncogenic hijacking of developmental transcription factors can dysregulate transcription through widespread effects on the spatial organization of cancer genomes.
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http://dx.doi.org/10.1016/j.molcel.2019.01.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6485942PMC
March 2019

Long genes linked to autism spectrum disorders harbor broad enhancer-like chromatin domains.

Genome Res 2018 07 30;28(7):933-942. Epub 2018 May 30.

Department of Genetics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA.

Genetic variants associated with autism spectrum disorders (ASDs) are enriched in genes encoding synaptic proteins and chromatin regulators. Although the role of synaptic proteins in ASDs is widely studied, the mechanism by which chromatin regulators contribute to ASD risk remains poorly understood. Upon profiling and analyzing the transcriptional and epigenomic features of genes expressed in the cortex, we uncovered a unique set of long genes that contain broad enhancer-like chromatin domains (BELDs) spanning across their entire gene bodies. Analyses of these BELD genes show that they are highly transcribed with frequent RNA polymerase II (Pol II) initiation and low Pol II pausing, and they exhibit frequent chromatin-chromatin interactions within their gene bodies. These BELD features are conserved from rodents to humans, are enriched in genes involved in synaptic function, and appear post-natally concomitant with synapse development. Importantly, we find that BELD genes are highly implicated in neurodevelopmental disorders, particularly ASDs, and that their expression is preferentially down-regulated in individuals with idiopathic autism. Finally, we find that the transcription of BELD genes is particularly sensitive to alternations in ASD-associated chromatin regulators. These findings suggest that the epigenomic regulation of BELD genes is important for post-natal cortical development and lend support to a model by which mutations in chromatin regulators causally contribute to ASDs by preferentially impairing BELD gene transcription.
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http://dx.doi.org/10.1101/gr.233775.117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6028126PMC
July 2018

Biotin tagging of MeCP2 in mice reveals contextual insights into the Rett syndrome transcriptome.

Nat Med 2017 Oct 18;23(10):1203-1214. Epub 2017 Sep 18.

Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA.

Mutations in MECP2 cause Rett syndrome (RTT), an X-linked neurological disorder characterized by regressive loss of neurodevelopmental milestones and acquired psychomotor deficits. However, the cellular heterogeneity of the brain impedes an understanding of how MECP2 mutations contribute to RTT. Here we developed a Cre-inducible method for cell-type-specific biotin tagging of MeCP2 in mice. Combining this approach with an allelic series of knock-in mice carrying frequent RTT-associated mutations (encoding T158M and R106W) enabled the selective profiling of RTT-associated nuclear transcriptomes in excitatory and inhibitory cortical neurons. We found that most gene-expression changes were largely specific to each RTT-associated mutation and cell type. Lowly expressed cell-type-enriched genes were preferentially disrupted by MeCP2 mutations, with upregulated and downregulated genes reflecting distinct functional categories. Subcellular RNA analysis in MeCP2-mutant neurons further revealed reductions in the nascent transcription of long genes and uncovered widespread post-transcriptional compensation at the cellular level. Finally, we overcame X-linked cellular mosaicism in female RTT models and identified distinct gene-expression changes between neighboring wild-type and mutant neurons, providing contextual insights into RTT etiology that support personalized therapeutic interventions.
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http://dx.doi.org/10.1038/nm.4406DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5630512PMC
October 2017

GR Extinguishes Inflamed Chromatin, and NF-κB Evacuates.

Immunity 2017 08;47(2):214-216

Department of Genetics, Institute for Immunology, Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA. Electronic address:

In this issue of Immunity,Oh et al. (2017) provide insight into the molecular effects of glucocorticoid receptor (GR) activation at a clinically relevant time point, after an inflammatory stimulus. They report that GR activation causes a global reduction in NF-κB binding, as well as time-dependent transcriptional effects.
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http://dx.doi.org/10.1016/j.immuni.2017.07.025DOI Listing
August 2017

The Crucial Role of DNA Methylation and MeCP2 in Neuronal Function.

Genes (Basel) 2017 May 13;8(5). Epub 2017 May 13.

Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.

A neuron is unique in its ability to dynamically modify its transcriptional output in response to synaptic activity while maintaining a core gene expression program that preserves cellular identity throughout a lifetime that is longer than almost every other cell type in the body. A contributing factor to the immense adaptability of a neuron is its unique epigenetic landscape that elicits locus-specific alterations in chromatin architecture, which in turn influences gene expression. One such epigenetic modification that is sensitive to changes in synaptic activity, as well as essential for maintaining cellular identity, is DNA methylation. The focus of this article is on the importance of DNA methylation in neuronal function, summarizing recent studies on critical players in the establishment of (the "writing"), the modification or erasure of (the "editing"), and the mediation of (the "reading") DNA methylation in neurodevelopment and neuroplasticity. One "reader" of DNA methylation in particular, methyl-CpG-binding protein 2 (MeCP2), is highlighted, given its undisputed importance in neuronal function.
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http://dx.doi.org/10.3390/genes8050141DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5448015PMC
May 2017

Locus- and cell type-specific epigenetic switching during cellular differentiation in mammals.

Front Biol (Beijing) 2016 Aug 18;11(4):311-322. Epub 2016 Jul 18.

Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.

Background: Epigenomic reconfiguration, including changes in DNA methylation and histone modifications, is crucial for the differentiation of embryonic stem cells (ESCs) into somatic cells. However, the extent to which the epigenome is reconfigured and the interplay between components of the epigenome during cellular differentiation remain poorly defined.

Methods: We systematically analyzed and compared DNA methylation, various histone modification, and transcriptome profiles in ESCs with those of two distinct types of somatic cells from human and mouse.

Results: We found that global DNA methylation levels are lower in somatic cells compared to ESCs in both species. We also found that 80% of regions with histone modification occupancy differ between human ESCs and the two human somatic cell types. Approximately 70% of the reconfigurations in DNA methylation and histone modifications are locus- and cell type-specific. Intriguingly, the loss of DNA methylation is accompanied by the gain of different histone modifications in a locus- and cell type-specific manner. Further examination of transcriptional changes associated with epigenetic reconfiguration at promoter regions revealed an epigenetic switching for gene regulation-a transition from stable gene silencing mediated by DNA methylation in ESCs to flexible gene repression facilitated by repressive histone modifications in somatic cells.

Conclusions: Our findings demonstrate that the epigenome is reconfigured in a locus- and cell type-specific manner and epigenetic switching is common during cellular differentiation in both human and mouse.
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http://dx.doi.org/10.1007/s11515-016-1411-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5336297PMC
August 2016

Distinct cellular and molecular environments support aging-related DNA methylation changes in the substantia nigra.

Epigenomics 2017 01 16;9(1):21-31. Epub 2016 Dec 16.

Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.

Aim: We aimed to couple brain region-specific changes in global DNA methylation over aging to underlying cellular and molecular environments.

Materials & Methods: We measured two major forms of DNA methylation and analyzed Dnmt, Tet and metabolite levels in the striatum and substantia nigra (SN) over aging in healthy male mice.

Results: The ratio of 5-hydroxymethylcytosine to 5-methylcytosine increases over aging in the SN, and 5-hydroxymethylcytosine increases preferentially in dopaminergic neurons. Additionally, this age-dependent alteration in methylation correlates with a reduction in the ratio of α-ketoglutarate to succinate in the SN.

Conclusion: Distinct cellular and molecular environments correlate with aging-associated methylation changes in the SN, implicating this epigenetic mechanism in the susceptibility of this brain region to age-related cell loss.
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http://dx.doi.org/10.2217/epi-2016-0084DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5514978PMC
January 2017

Obesity diminishes synaptic markers, alters microglial morphology, and impairs cognitive function.

Proc Natl Acad Sci U S A 2015 Dec 7;112(51):15731-6. Epub 2015 Dec 7.

Department of Psychology, Princeton University, Princeton, NJ 08544; Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08544;

Obesity is a major public health problem affecting overall physical and emotional well-being. Despite compelling data suggesting an association between obesity and cognitive dysfunction, this phenomenon has received relatively little attention. Neuroimaging studies in obese humans report reduced size of brain regions involved in cognition, but few studies have investigated the cellular processes underlying cognitive decline in obesity or the influence of obesity on cognition in the absence of obesity-related illnesses. Here, a rat model of diet-induced obesity was used to explore changes in brain regions important for cognition. Obese rats showed deficits on cognitive tasks requiring the prefrontal and perirhinal cortex. Cognitive deficits were accompanied by decreased dendritic spine density and synaptic marker expression in both brain regions. Microglial morphology was also changed in the prefrontal cortex. Detrimental changes in the prefrontal cortex and perirhinal cortex occurred before metabolic syndrome or diabetes, suggesting that these brain regions may be particularly vulnerable to early stage obesity.
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http://dx.doi.org/10.1073/pnas.1511593112DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4697408PMC
December 2015

Sexual experience enhances cognitive flexibility and dendritic spine density in the medial prefrontal cortex.

Neurobiol Learn Mem 2015 Nov 15;125:73-9. Epub 2015 Jul 15.

Department of Psychology and Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08544, USA. Electronic address:

The medial prefrontal cortex is important for cognitive flexibility, a capability that is affected by environmental conditions and specific experiences. Aversive experience, such as chronic restraint stress, is known to impair performance on a task of cognitive flexibility, specifically attentional set-shifting, in rats. Concomitant with this performance decrement, chronic stress reduces the number of dendritic spines on pyramidal neurons in the medial prefrontal cortex. No previous studies have examined whether a rewarding experience, namely mating, affects cognitive flexibility and dendritic spines in the medial prefrontal cortex of male rats. To test this possibility, we exposed adult male rats to sexual receptive females once daily for one week, assessed attentional set-shifting performance, and then analyzed their brains for changes in dendritic spines. We found that sexual experience improved performance on extradimensional set-shifting, which is known to require the medial prefrontal cortex. Additionally, we observed increased dendritic spine density on apical and basal dendrites of pyramidal neurons in the medial prefrontal cortex, but not the orbitofrontal cortex, after sexual experience. We also found that sexual experience enhanced dendritic spine density on granule neurons of the dentate gyrus. The ventral hippocampus sends a direct projection to the medial prefrontal cortex, raising the possibility that experience-dependent changes in the hippocampus are necessary for alterations in medial prefrontal cortex structure and function. As a first attempt at investigating this, we inactivated the ventral hippocampus with the GABA agonist muscimol, after each daily bout of sexual experience to observe whether the beneficial effects on cognitive flexibility were abolished. Contrary to our hypothesis, blocking hippocampal activity after sexual experience had no impact on enhanced cognitive flexibility. Taken together, these findings indicate that sexual experience enhances medial prefrontal cortex dendritic spine density and cognitive flexibility but that these effects may not require continual input from the hippocampus.
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http://dx.doi.org/10.1016/j.nlm.2015.07.007DOI Listing
November 2015

Exome sequencing to identify de novo mutations in sporadic ALS trios.

Nat Neurosci 2013 Jul 26;16(7):851-5. Epub 2013 May 26.

Department of Genetics, Stanford University School of Medicine, Stanford, California, USA.

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease whose causes are still poorly understood. To identify additional genetic risk factors, we assessed the role of de novo mutations in ALS by sequencing the exomes of 47 ALS patients and both of their unaffected parents (n = 141 exomes). We found that amino acid-altering de novo mutations were enriched in genes encoding chromatin regulators, including the neuronal chromatin remodeling complex (nBAF) component SS18L1 (also known as CREST). CREST mutations inhibited activity-dependent neurite outgrowth in primary neurons, and CREST associated with the ALS protein FUS. These findings expand our understanding of the ALS genetic landscape and provide a resource for future studies into the pathogenic mechanisms contributing to sporadic ALS.
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http://dx.doi.org/10.1038/nn.3412DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3709464PMC
July 2013

Cervical pregnancy: a case series and a review of current clinical practice.

Eur J Contracept Reprod Health Care 2008 Sep;13(3):313-9

Department of Obstetrics and Gynaecology, General Hospital S. Giovanni di Dio e Ruggi d'Aragona-Salerno, Italy.

Five consecutive cases of cervical pregnancy (CP) are presented. In four cases, the diagnosis was made at routine check-ups and these were all treated conservatively. In the fifth case, an erroneous diagnosis of inevitable abortion was made, in a patient presenting with profuse vaginal bleeding. Persistent bleeding following curettage required an emergency hysterectomy, after failure of compressive methods. From the four cases treated conservatively, three received standard methotrexate i.m. (MTX) in combination with bilateral uterine artery embolization (UAE). In one case MTX was followed by intraamniotic puncture and instillation of KCl due to persistent embryonic heartbeat. A spontaneous evacuation of the cervical pregnancy occurred in all patients treated conservatively. We postulate that the preventive use of uterine artery embolization in combination with standard MTX treatment could contribute to reduce the risk of excessive bleeding and facilitate spontaneous expulsion. Possible detrimental effects of the treatment on subsequent reproductive capacities and obstetrical outcome are also pointed out. The diagnostic methods and therapeutic approaches are discussed and the literature is reviewed. With referral to the first case of our series, which required an emergency hysterectomy, we want to stress the importance of an early diagnosis for a correct management of this condition.
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http://dx.doi.org/10.1080/13625180802254571DOI Listing
September 2008
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