Project description:Ribosomal protein dysfunction leads to diverse human diseases, including Diamond-Blackfan anemia (DBA). Despite the ubiquitous need for ribosomes in all cell types, the mechanisms underlying ribosomopathies manifesting with tissue-specific defects are still incompletely understood. In this study, at single cell resolution, we characterized the transcriptomes of highly-purified erythroid progenitors isolated from bone marrow (BM) of DBA patients, including non-treatment (NT), glucocorticoids (GC)-responsive (GCR) and GC-non-responsive (GCNR) patients. We uncovered that, rather than cell cycle arrest at G1 phase, erythroid progenitors in NT patients were compulsively entering cell cycle of S-phase, which triggered replication stress and consequently activated P53 pathway. In contrast, the cell cycle was restrained with compromised proliferation in GCR patients, but not GCNR counterparts, via elevating IFN pathway. More importantly, the combinational treatment of DEX and IFN exhibit a synergistic effect on erythrocytes from GCNR patients. Therefore, the innate cell cycle characteristics of erythroid progenitors is ascribed to the erythroid lineage specific defects of DBA. Controlling the cell cycle progression by IFN signaling underlies the GC clinical efficacy and combinational therapy of DEX and IFN holds great promise for GCNR patients.
Project description:Ribosomal protein dysfunction causes diverse human diseases, including Diamond-Blackfan anemia (DBA). Despite the universal need for ribosomes in all cell types, the mechanisms underlying ribosomopathies, which are characterized by tissue-specific defects, are still poorly understood. In the present study, we analyzed the transcriptomes of single purified erythroid progenitors isolated from the bone marrow of DBA patients. These patients were categorized into untreated, glucocorticoid (GC)-responsive and GC-non-responsive groups. We found that erythroid progenitors from untreated DBA patients entered S-phase of the cell cycle under considerable duress, resulting in replication stress and the activation of P53 signaling. In contrast, cell cycle progression was inhibited through induction of the type 1 interferon pathway in treated, GC-responsive patients, but not in GC-non-responsive patients. Notably, a low dose of interferon alpha treatment stimulated the production of erythrocytes derived from DBA patients. By linking the innately shorter cell cycle of erythroid progenitors to DBA pathogenesis, we demonstrated that interferon-mediated cell cycle control underlies the clinical efficacy of glucocorticoids. Our study suggests that interferon administration may constitute a new alternative therapeutic strategy for the treatment of DBA. The trial was registered at www.chictr.org.cn as ChiCTR2000038510.
Project description:Cellular reprogramming is driven by a defined set of transcription factors; however, the regulatory logic that underlies cell-type specification and diversification remains elusive. Single-cell RNA-seq provides unprecedented coverage to measure dynamic molecular changes at the single-cell resolution. Here, we multiplex and ectopically express 20 pro-neuronal transcription factors in human dermal fibroblasts and demonstrate a widespread diversification of neurons based on cell morphology and canonical neuronal marker expressions. Single-cell RNA-seq analysis reveals diverse and distinct neuronal subtypes, including reprogramming processes that strongly correlate with the developing brain. Gene mapping of 20 exogenous pro-neuronal transcription factors further unveiled key determinants responsible for neuronal lineage specification and a regulatory logic dictating neuronal diversification, including glutamatergic and cholinergic neurons. The multiplex scRNA-seq approach is a robust and scalable approach to elucidate lineage and cellular specification across various biological systems.
Project description:To understand how distinct memories are formed and stored in the brain is an important and fundamental question in neuroscience and computational biology. A population of neurons, termed engram cells, represents the physiological manifestation of a specific memory trace and is characterized by dynamic changes in gene expression, which in turn alters the synaptic connectivity and excitability of these cells. Recent applications of single-cell RNA sequencing (scRNA-seq) and single-nucleus RNA sequencing (snRNA-seq) are promising approaches for delineating the dynamic expression profiles in these subsets of neurons, and thus understanding memory-specific genes, their combinatorial patterns and regulatory networks. The aim of this article is to review and discuss the experimental and computational procedures of sc/snRNA-seq, new studies of molecular mechanisms of memory aided by sc/snRNA-seq in human brain diseases and related mouse models, and computational challenges in understanding the regulatory mechanisms underlying long-term memory formation.