Project description:Neural activity is increasingly recognized as a crucial regulator of cancer growth. In the brain, neuronal activity robustly influences glioma growth both through paracrine mechanisms and through electrochemical integration of malignant cells into neural circuitry via neuron-to-glioma synapses. Outside of the CNS, innervation of tumors such as prostate, breast, pancreatic and gastrointestinal cancers by peripheral nerves similarly regulates cancer progression. However, the extent to which the nervous system regulates lung cancer progression, either in the lung or when metastatic to brain, is less well understood. Small cell lung cancer (SCLC) is a lethal high-grade neuroendocrine tumor that exhibits a strong propensity to metastasize to the brain. Here we demonstrate that SCLC cells in the brain co-opt neuronal activity-regulated mechanisms to stimulate growth and progression. Glutamatergic and GABAergic cortical neuronal activity each drive proliferation of SCLC in the brain through both paracrine and synaptic neuron-cancer interactions. In the brain, SCLC cells form bona fide neuron-to-SCLC synapses and exhibit depolarizing currents with consequent calcium transients in response to neuronal activity. SCLC cell membrane depolarization is sufficient to promote the growth of intracranial tumors. In the lung, vagus nerve transection markedly inhibits primary lung tumor formation and development, highlighting a critical role for innervation in overall SCLC growth. Taken together, these studies illustrate that neuronal activity plays a crucial role in dictating SCLC pathogenesis in both the lung and the brain.
Project description:The GGGGCC nucleotide repeat expansion (NRE) mutation in the C9orf72 (C9) gene is the most common cause of ALS and FTD. Neuronal activity plays an essential role in shaping biological processes within both healthy and neurodegenerative disease scenarios. Here, we show that at baseline conditions, C9-NRE iPSC-cortical neurons display aberrations in several pathways, including synaptic signaling and transcriptional machinery, potentially priming diseased neurons for an altered response to neuronal stimulation. Indeed, exposure to two pathophysiologically relevant stimulation modes, prolonged membrane depolarization, or a blockade of K+ channels, followed by RNA sequencing, induces a temporally divergent activity-dependent transcriptome of C9-NRE cortical neurons compared to healthy controls. These findings reveal the impact of neuronal activity on the ALS/FTD-associated transcriptome and may reveal pathways necessary for conferring neuronal resilience or degeneration.
Project description:<p>The goal of this proposal is to bring together the power of 1) whole exome sequencing, 2) homozygosity mapping in consanguineous families, 3) genome-wide maps of neuronal transcription in response to neuronal activity, and 4) genome-wide maps of the binding sites of factors that regulate this transcription to generate and annotate a catalog of ASD-associated variants. The consanguineous families are already enrolled in research, and have been phenotyped. The neuronal transcription and binding site maps will be developed by the Greenberg Lab at Harvard Medical School. The whole exome sequencing will be done at the Broad Institute, and the Walsh lab at Children's Hospital will validate the results and analyze the variant data.</p>
Project description:Experience-dependent gene transcription is required for nervous system development and function. However, the DNA regulatory elements that control this program of gene expression are not well defined. Here we characterize the enhancers that function across the genome to mediate activity-dependent transcription in neurons. While ~12,000 putative activity-regulated enhancer sequences have previously been identified that are enriched for H3K4me1 and the histone acetyltransferase CBP, we find that this chromatin signature is not sufficient to distinguish which of these regulatory sequences are actively engaged in promoting activity-dependent transcription. We show here that a subset of H3K4me1/CBP positive enhancers that is enriched for H3K27 acetylation (H3K27ac) in vivo, and shows increased H3K27ac upon membrane depolarization of cortical neurons, function to regulate activity-dependent transcription. The function of many of these activity-regulated enhancers appears to be dependent on the binding of FOS, a protein that had previously been thought to interact primarily with the promoters of activity-regulated genes. Furthermore, many of these target genes in cortical neurons encode neuron specific proteins that regulate synaptic development and function. These findings suggest that FOS functions at enhancers to control activity-dependent gene programs that are critical for nervous system function, and provide a resource of activity-dependent enhancers that may give insight into genetic variation that contributes to brain development and disease. Genome-wide maps of H3K27ac and AP1 transcription factors (CFOS, FOSB, JUNB) before and after neuronal activity in mouse cortical neurons.
Project description:The study investigates the role of NF1 mutation and neuronal activity on the initiation of optic pathway glioma, a type of low-grade glioma. the RNAseq dataset investigates mRNA expression profile of human pilocytic astrocytomas (WHO grade I)