Project description:SH-SY5Y, neuroblastoma cells, were exposed to nicotine for 10, 60, and 90 minutes or cocaine for 5, 20, 40, and 60 minutes. Drugs of abuse modify behavior by altering gene expression in the brain. Gene expression can be regulated by changes in DNA methylation as well as by histone modifications, which alter chromatin structure, DNA compaction and DNA accessibility. In order to better understand the molecular mechanisms directing drug-induced changes in chromatin structure, we examined DNA-nucleosome interactions within promoter regions of 858 genes in human neuroblastoma cells (SH-SY5Y) exposed to nicotine or cocaine. Widespread, drug- and time-resolved repositioning of nucleosomes was identified at the transcription start site and promoter region of multiple genes. Nicotine and cocaine produced unique and shared changes in terms of the numbers and types of genes affected, as well as repositioning of nucleosomes at sites which could increase or decrease the probability of gene expression based on DNA accessibility. Half of the drug-induced nucleosome positions approximated a theoretical model of nucleosome occupancy based on physical and chemical characteristics of the DNA sequence, whereas the basal or drug-naive positions were generally DNA sequence independent. Thus we suggest that nucleosome repositioning represents an initial dynamic genome-wide alteration of the transcriptional landscape preceding more selective downstream transcriptional reprogramming, which ultimately characterizes the cell- and tissue-specific responses to drugs of abuse. SH-SY5Y, neuroblastoma cells, were exposed to nicotine for 10, 60, and 90 minutes or cocaine for 5, 20, 40, and 60 minutes. Two independently grown biological replicates for each time point and condition, and two controls were processed.
Project description:SH-SY5Y, neuroblastoma cells, were exposed to nicotine for 10, 60, and 90 minutes or cocaine for 5, 20, 40, and 60 minutes. Drugs of abuse modify behavior by altering gene expression in the brain. Gene expression can be regulated by changes in DNA methylation as well as by histone modifications, which alter chromatin structure, DNA compaction and DNA accessibility. In order to better understand the molecular mechanisms directing drug-induced changes in chromatin structure, we examined DNA-nucleosome interactions within promoter regions of 858 genes in human neuroblastoma cells (SH-SY5Y) exposed to nicotine or cocaine. Widespread, drug- and time-resolved repositioning of nucleosomes was identified at the transcription start site and promoter region of multiple genes. Nicotine and cocaine produced unique and shared changes in terms of the numbers and types of genes affected, as well as repositioning of nucleosomes at sites which could increase or decrease the probability of gene expression based on DNA accessibility. Half of the drug-induced nucleosome positions approximated a theoretical model of nucleosome occupancy based on physical and chemical characteristics of the DNA sequence, whereas the basal or drug-naive positions were generally DNA sequence independent. Thus we suggest that nucleosome repositioning represents an initial dynamic genome-wide alteration of the transcriptional landscape preceding more selective downstream transcriptional reprogramming, which ultimately characterizes the cell- and tissue-specific responses to drugs of abuse.
Project description:It is widely believed that reorganization of nucleosomes result in availability of transcription factor (TF) binding sites for eukaryotic gene regulation. Recent findings also show TFs induced during physiological perturbations can alter nucleosome occupancy to facilitate DNA binding. Although, these suggest a close relationship between TF binding and nucleosomes, the nature of this interaction, or to what extent it influences transcription is not clear. Moreover, since physiological perturbations induced multiple TFs, relatively direct effect of any TF on nucleosome occupancy remains poorly addressed. With these in mind, we used a single TF to induce physiological changes and following characterization of the two states (before and after induction of the TF) we determined: (a) genome wide binding sites of the TF, (b) promoter nucleosome occupancy and (c) transcriptome profiles, independently in both conditions. We find only ~20% of TF binding results from nucleosome repositioning - interestingly, almost all corresponding genes were transcriptionally altered. Whereas, when TF-occupancy was independent of nucleosome repositioning only a small fraction of corresponding genes were expressed/repressed. These observations suggest a model where TF occupancy leads to transcriptional change only when coupled with nucleosome repositioning in close proximity. This, to our knowledge, for the first time also helps explain why genome wide TF occupancy (e.g., from ChIP-sequencing) typically overlaps with only a small fraction of genes that change expression. The nature of interaction between TF binding and nucleosomes and what extent it influences transcription
Project description:Analysis of ex vivo isolated lymphatic endothelial cells from the dermis of patients to define type 2 diabetes-induced changes. Results preveal aberrant dermal lymphangiogenesis and provide insight into its role in the pathogenesis of persistent skin inflammation in type 2 diabetes. The ex vivo dLEC transcriptome reveals a dramatic influence of the T2D environment on multiple molecular and cellular processes, mirroring the phenotypic changes seen in T2D affected skin. The positively and negatively correlated dLEC transcripts directly cohere to prolonged inflammatory periods and reduced infectious resistance of patients´ skin. Further, lymphatic vessels might be involved in tissue remodeling processes during T2D induced skin alterations associated with impaired wound healing and altered dermal architecture. Hence, dermal lymphatic vessels might be directly associated with T2D disease promotion.
Project description:Drug-induced alterations in gene expression play an important role in the development of addictive behavior. Methionine has been proven to inhibit addictive behaviors of cocaine dependence. However, the mechanisms underlying how methionine use corresponds to drug-induced behaviors still remain unclear. We performed mRNA and miRNA high-throughput sequencing of the prefrontal cortex in a mouse model of cocaine CPP combined with L-methionine in order to identify L-methionine target miRNAs and genes that participate in the cocaine conditioned place preference (CPP). We found that the L-methionine inhibits cocaine CPP. Sequencing data analysis showed that L-methionine down-regulates genes enriched in the Glutamatergic Synapse pathways and significantly reversed the cocaine-induced expression changes of the substance dependence pathways (Morphine addiction and Nicotine addiction) and the neurotransmitter synapse pathways (Glutamatergic Synapse, Cholinergic Synapse and GABAergic Synapse). Furthermore, the Glutamatergic synapse was either overlapped between DEGs with DEGs-miRNA induced by cocaine CPP, or with the MET effects on cocaine CPP. Nineteen targeted genes were investigated and five were identified (Gria4, Grid1, Grik4, Grik5 and Grin3a) to belong to iGluR family. Interestingly, there were several miRNAs that had the same sequence which targets the iGluR family: Mmu-miR-30e-50p and mmu-miR-380-5p share UUGAC motif and targets Grik4; mmu-miR-6940-3p and mmu-miR-212-5p both share UGGCU motif which targets Gria4 and Grid1 respectively. Thus, we demonstrated the efficacy of L-methionine in counteracting the effects of cocaine CPP and identified specific genes of synaptic plasticity pathways, especially the Glutamatergic synapse pathway, which is modulated by L-methionine in response to cocaine dependence.