Project description:Surprisingly little is known about the critical metabolic changes that neural cells have to undergo during development and how even mild, temporary shifts in this program can influence brain circuitries and behavior. Inspired by the discovery that mutations in SLC7A5, a transporter of metabolically-essential large neutral amino acids (LNAAs), lead to autism, we employed metabolomic profiling to study the metabolic states of the cerebral cortex across different developmental stages. We found that the forebrain undergoes significant metabolic remodeling throughout development, with certain groups of metabolites showing stage-specific changes. But what are the consequences of interfering with this metabolic program? By manipulating Slc7a5 expression in neural cells, we found that the metabolism of LNAAs and lipids are interconnected in the cortex. Deletion of Slc7a5 in neurons perturbs specifically the postnatal metabolic state leading to a shift in lipid metabolism and a stage- and cell-type-specific alteration in neuronal activity patterns, resulting in a long-term circuit dysfunction.
Project description:Surprisingly little is known about the critical metabolic changes that neural cells have to undergo during development and how even mild, temporary shifts in this program can influence brain circuitries and behavior. Inspired by the discovery that mutations in SLC7A5, a transporter of metabolically essential large neutral amino acids (LNAAs), lead to autism, we employed metabolomic profiling to study the metabolic states of the cerebral cortex across different developmental stages. We found that the forebrain undergoes significant metabolic remodeling throughout development, with certain groups of metabolites showing stage-specific changes. But what are the consequences of interfering with this metabolic program? By manipulating Slc7a5 expression in neural cells, we found that the metabolism of LNAAs and lipids are interconnected in the cortex. Deletion of Slc7a5 in neurons perturbs specifically the postnatal metabolic state leading to a shift in lipid metabolism and a stage- and cell-type-specific alteration in neuronal activity patterns, resulting in a long-term circuit dysfunction.
Project description:Surprisingly little is known about the critical metabolic changes that neural cells have to undergo during development and how even mild, temporary shifts in this program can influence brain circuitries and behavior. Inspired by the discovery that mutations in SLC7A5, a transporter of metabolically-essential large neutral amino acids (LNAAs), lead to autism, we employed metabolomic profiling to study the metabolic states of the cerebral cortex across different developmental stages. We found that the forebrain undergoes significant metabolic remodeling throughout development, with certain groups of metabolites showing stage-specific changes. But what are the consequences of interfering with this metabolic program? By manipulating Slc7a5 expression in neural cells, we found that the metabolism of LNAAs and lipids are interconnected in the cortex. Deletion of Slc7a5 in neurons perturbs specifically the postnatal metabolic state leading to a shift in lipid metabolism and a stage- and cell- type-specific alteration in neuronal activity patterns, resulting in a long-term circuit dysfunction.
Project description:Hypertonicity in renal medulla is essential for urine concentration and water homeostasis. However, how renal medullary collecting duct cells (MCDs) survive and function under the harsh hypertonic stress remains incompletely understood. By using the RNA-seq technique, we identified SNAT2 (slc38a2) as a novel osmoresponsive neutral amino acid transporter in MCD cells. We found that hypertonic stress induced cell death of MCDs mainly via ferroptosis.
Project description:CRISPR-enabled genetic screening is a powerful tool to discover genes that control T cell function and has nominated candidate target genes for immunotherapies1–6. However, new approaches are required to probe specific nucleotide sequences within key genes. Systematic mutagenesis in primary human T cells could discover alleles that tune specific phenotypes. DNA base editors are powerful tools to introduce targeted mutations with high efficiency7,8. Here, we develop a large-scale base editing mutagenesis platform with the goal of pinpointing nucleotides encoding amino acid residues that tune primary human T cell activation responses. We generated a library of ~117,000 sgRNAs targeting base editors to protein coding sites across 385 genes implicated in T cell function and systematically identified protein domains and specific amino acid residues that regulate T cell activation and cytokine production. We discovered a broad spectrum of alleles with variants encoding critical residues (in PIK3CD, VAV1, LCP2, PLCG1 and DGKZ and others), comprising both gain-of-function and loss-of-function mutations. We validated the functional effects of diverse alleles and further demonstrated that base edit hits could positively and negatively tune T cell cytotoxic function. Finally, higher-resolution screening using a base editor with relaxed PAM requirements9 (NG versus NGG) revealed specific structural domains and protein-protein interaction sites that can be targeted to tune T cell functions. Base editing screens in primary immune cells provide biochemical insights with potential to accelerate immunotherapy design.
Project description:In order to understand the transcriptional regulatory program of cardiomyocytes perinatal transition, we mapped chromatin accessibility, transcription-centered long-range chromatin interactions as well as gene expression in cardiomyocyte undergoing perinatal transition.
Project description:Electrical excitability—the ability to fire and propagate action potentials—is a signature feature of neurons. How neurons become excitable during development and whether excitability is an intrinsic property of neurons or requires signaling from glial cells remain unclear. Here, we demonstrate that Schwann cells, the most abundant glia in the peripheral nervous system, promote somatosensory neuron excitability during development. We find that Schwann cells secrete prostaglandin E2, which is necessary and sufficient to induce developing somatosensory neurons to express normal levels of genes required for neuronal function, including voltage gated sodium channels, and to fire action potential trains. In this RNA-Seq study, we discovered that treating cultured DRG neurons with Schwann cell-conditioned media or PGE2 increased the expression of several genes required for neuronal maturation and excitability, including voltage-gated sodium channels.