Project description:Cellular reprogramming using chemically defined conditions, without genetic manipulation, is a promising approach for generating clinically relevant cell types for regenerative medicine and drug discovery. However, small molecule-driven approaches for inducing lineage-specific stem cells from somatic cells across lineage boundaries have been challenging to develop. Here, we report highly efficient reprogramming of mouse fibroblasts into induced neural stem cell-like cells (ciNSLCs) using a cocktail of nine small molecules (M9). The resulting ciNSLCs closely resemble primary neural stem cells molecularly and functionally. Transcriptome analysis revealed that M9 induces a gradual and specific conversion of fibroblasts towards a neural fate. During reprogramming specific transcription factors such as Elk1 and Gli2 that are downstream of M9-induced signaling pathways bind and activate endogenous master neural genes to specify neural identity. Our study therefore provides an effective chemical approach for generating neural stem cells from mouse fibroblasts, and reveals mechanistic insights into underlying reprogramming process. Genome-wide binding of Elk1 and Gli2 was analyzed by CHIP-seq for tdMEFs from day 0 (ciNSLC), day 4 (D4), day 8 (D8) of M9-induced neural reprogramming, and ciNSLCs and pri-NPC.
Project description:Cellular reprogramming using chemically defined conditions, without genetic manipulation, is a promising approach for generating clinically relevant cell types for regenerative medicine and drug discovery. However, small molecule-driven approaches for inducing lineage-specific stem cells from somatic cells across lineage boundaries have been challenging to develop. Here, we report highly efficient reprogramming of mouse fibroblasts into induced neural stem cell-like cells (ciNSLCs) using a cocktail of nine small molecules (M9). The resulting ciNSLCs closely resemble primary neural stem cells molecularly and functionally. Transcriptome analysis revealed that M9 induces a gradual and specific conversion of fibroblasts towards a neural fate. During reprogramming specific transcription factors such as Elk1 and Gli2 that are downstream of M9-induced signaling pathways bind and activate endogenous master neural genes to specify neural identity. Our study therefore provides an effective chemical approach for generating neural stem cells from mouse fibroblasts, and reveals mechanistic insights into underlying reprogramming process. Genome-wide epigenetic changes of H3K4me1, H3K4me3, H3K27me3, and H3K27ac were analyzed by CHIP-seq for tdMEFs from day 0 (ciNSLC), day 4 (D4), day 8 (D8) of M9-induced neural reprogramming, and ciNSLCs and pri-NPC.
Project description:Somatic cells can be reprogrammed to generate induced pluripotent stem cells (iPSCs) by overexpression of four transcription factors, Oct4, Klf4, Sox2, and c-Myc. Bmi1 is responsible for conversion of adult mouse astrocytes and fibroblasts into neural stem cell-like cells and conversion of fibroblasts into iPSCs under enforced expression of Oct4. Here, in the first step of generating iPSCs, stable intermediate cells were generated from mouse astrocytes by Bmi1 in the absence of other transcription factors. These cells [called induced epiblast stem cell (EpiSC)-like cells (iEpiSCLCs)] are similar to EpiSCs in terms of expression of specific markers, epigenetic state, and ability to differentiate into three germ layers. Treatment with MEK/ERK and GSK3 pathway inhibitors in the presence of leukemia inhibitory factor resulted in conversion of iEpiSCLCs into iPSCs that were similar to mouse embryonic stem cells (mESCs), suggesting that Bmi1 is sufficient to reprogram astrocytes to pluripotency. Next, Bmi1 function was replaced with Shh activators (oxysterol and purmorphamine), which demonstrated that specific combinations of small molecules alone can reprogram mouse fibroblasts into iPSCs. These iPSCs resembled mESCs in terms of global gene expression profile, epigenetic status, and developmental potential, demonstrating that combinations of small molecules can compensate for reprogramming factors and are sufficient to directly reprogram mouse somatic cells into iPSCs. 4 Affymetrix and 4 Agilent samples
Project description:Cellular reprogramming using chemically defined conditions, without genetic manipulation, is a promising approach for generating clinically relevant cell types for regenerative medicine and drug discovery. However, small molecule-driven approaches for inducing lineage-specific stem cells from somatic cells across lineage boundaries have been challenging to develop. Here, we report highly efficient reprogramming of mouse fibroblasts into induced neural stem cell-like cells (ciNSLCs) using a cocktail of nine small molecules (M9). The resulting ciNSLCs closely resemble primary neural stem cells molecularly and functionally. Transcriptome analysis revealed that M9 induces a gradual and specific conversion of fibroblasts towards a neural fate. During reprogramming specific transcription factors such as Elk1 and Gli2 that are downstream of M9-induced signaling pathways bind and activate endogenous master neural genes to specify neural identity. Our study therefore provides an effective chemical approach for generating neural stem cells from mouse fibroblasts, and reveals mechanistic insights into underlying reprogramming process.
Project description:Cellular reprogramming using chemically defined conditions, without genetic manipulation, is a promising approach for generating clinically relevant cell types for regenerative medicine and drug discovery. However, small molecule-driven approaches for inducing lineage-specific stem cells from somatic cells across lineage boundaries have been challenging to develop. Here, we report highly efficient reprogramming of mouse fibroblasts into induced neural stem cell-like cells (ciNSLCs) using a cocktail of nine small molecules (M9). The resulting ciNSLCs closely resemble primary neural stem cells molecularly and functionally. Transcriptome analysis revealed that M9 induces a gradual and specific conversion of fibroblasts towards a neural fate. During reprogramming specific transcription factors such as Elk1 and Gli2 that are downstream of M9-induced signaling pathways bind and activate endogenous master neural genes to specify neural identity. Our study therefore provides an effective chemical approach for generating neural stem cells from mouse fibroblasts, and reveals mechanistic insights into underlying reprogramming process.
Project description:Cellular reprogramming using chemically defined conditions, without genetic manipulation, is a promising approach for generating clinically relevant cell types for regenerative medicine and drug discovery. However, small molecule-driven approaches for inducing lineage-specific stem cells from somatic cells across lineage boundaries have been challenging to develop. Here, we report highly efficient reprogramming of mouse fibroblasts into induced neural stem cell-like cells (ciNSLCs) using a cocktail of nine small molecules (M9). The resulting ciNSLCs closely resemble primary neural stem cells molecularly and functionally. Transcriptome analysis revealed that M9 induces a gradual and specific conversion of fibroblasts towards a neural fate. During reprogramming specific transcription factors such as Elk1 and Gli2 that are downstream of M9-induced signaling pathways bind and activate endogenous master neural genes to specify neural identity. Our study therefore provides an effective chemical approach for generating neural stem cells from mouse fibroblasts, and reveals mechanistic insights into underlying reprogramming process.
Project description:Somatic cells can be reprogrammed to generate induced pluripotent stem cells (iPSCs) by overexpression of four transcription factors, Oct4, Klf4, Sox2, and c-Myc. Bmi1 is responsible for conversion of adult mouse astrocytes and fibroblasts into neural stem cell-like cells and conversion of fibroblasts into iPSCs under enforced expression of Oct4. Here, in the first step of generating iPSCs, stable intermediate cells were generated from mouse astrocytes by Bmi1 in the absence of other transcription factors. These cells [called induced epiblast stem cell (EpiSC)-like cells (iEpiSCLCs)] are similar to EpiSCs in terms of expression of specific markers, epigenetic state, and ability to differentiate into three germ layers. Treatment with MEK/ERK and GSK3 pathway inhibitors in the presence of leukemia inhibitory factor resulted in conversion of iEpiSCLCs into iPSCs that were similar to mouse embryonic stem cells (mESCs), suggesting that Bmi1 is sufficient to reprogram astrocytes to pluripotency. Next, Bmi1 function was replaced with Shh activators (oxysterol and purmorphamine), which demonstrated that specific combinations of small molecules alone can reprogram mouse fibroblasts into iPSCs. These iPSCs resembled mESCs in terms of global gene expression profile, epigenetic status, and developmental potential, demonstrating that combinations of small molecules can compensate for reprogramming factors and are sufficient to directly reprogram mouse somatic cells into iPSCs.