scholarly journals Ptbp1 deletion does not induce glia-to-neuron conversion in adult mouse retina and brain.

2021 ◽  
Author(s):  
Thanh Hoang ◽  
Dong Won Kim ◽  
Haley Appel ◽  
Nicole Pannullo ◽  
Manabu Ozawa ◽  
...  
Keyword(s):  
Adult Mouse ◽  
Genetic Manipulation ◽  
Lineage Tracing ◽  
Mouse Retina ◽  
Genetic Lineage ◽  
Type Conversion ◽  
Polypyrimidine Tract Binding Protein ◽  
Genetic Lineage Tracing ◽  
Cell Type Conversion ◽  
Specific Deletion

Somatic reprogramming of glia into neurons is a potentially promising approach for the replacement of neurons lost to injury or neurodegenerative disorders. Knockdown of the polypyrimidine tract-binding protein Ptbp1 has been recently reported to induce efficient conversion of retinal Mϋller glia and brain astrocytes into functional neurons. However, genetic analysis of Ptbp1 function in adult glia has not been conducted. Here, we use a combination of genetic lineage tracing, scRNA-Seq, and electrophysiological analysis to show that specific deletion of Ptbp1 in adult retinal Mϋller glia and brain astrocytes does not lead to any detectable level of glia-to-neuron conversion. Few changes in gene expression are observed in glia following Ptbp1 deletion, and glial identity is maintained. These findings highlight the importance of using genetic manipulation and lineage tracing methods in studying cell type conversion.

scholarly journals Paracrine Wnt/β-catenin signaling mediates proliferation of undifferentiated spermatogonia in the adult mouse testis

2016 ◽  
Vol 113 (11) ◽  
pp. E1489-E1497 ◽  
Author(s):  
Hinako M. Takase ◽  
Roeland Nusse
Keyword(s):  
Progenitor Cells ◽  
Germ Cells ◽  
Wnt Pathway ◽  
Target Gene ◽  
Adult Mouse ◽  
Lineage Tracing ◽  
Genetic Lineage ◽  
Self Renewal ◽  
Proliferation And Differentiation ◽  
Genetic Lineage Tracing

Spermatogonial stem cells (SSCs) fuel the production of male germ cells but the mechanisms behind SSC self-renewal, proliferation, and differentiation are still poorly understood. Using the Wnt target gene Axin2 and genetic lineage-tracing experiments, we found that undifferentiated spermatogonia, comprising SSCs and transit amplifying progenitor cells, respond to Wnt/β-catenin signals. Genetic elimination of β-catenin indicates that Wnt/β-catenin signaling promotes the proliferation of these cells. Signaling is likely initiated by Wnt6, which is uniquely expressed by neighboring Sertoli cells, the only somatic cells in the seminiferous tubule that support germ cells and act as a niche for SSCs. Therefore, unlike other stem cell systems where Wnt/β-catenin signaling is implicated in self-renewal, the Wnt pathway in the testis specifically contributes to the proliferation of SSCs and progenitor cells.

scholarly journals SETD4-expressing cells contribute to pancreatic development and response to cerulein induced pancreatitis injury

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jin-Ze Tian ◽  
Sheng Xing ◽  
Jing-Yi Feng ◽  
Shu-Hua Yang ◽  
Yan-Fu Ding ◽  
...  
Keyword(s):  
Cell Population ◽  
Acinar Cells ◽  
Pancreatic Disease ◽  
Lineage Tracing ◽  
Genetic Lineage ◽  
Pancreatic Development ◽  
Histone Lysine Methyltransferase ◽  
Population Potential ◽  
Potential Applications ◽  
Genetic Lineage Tracing

AbstractIn the adult pancreas, the presence of progenitor or stem cells and their potential involvement in homeostasis and regeneration remains unclear. Here, we identify that SET domain-containing protein 4 (SETD4), a histone lysine methyltransferase, is expressed in a small cell population in the adult mouse pancreas. Genetic lineage tracing shows that during pancreatic development, descendants of SETD4+ cells make up over 70% of pancreatic cells and then contribute to each pancreatic lineage during pancreatic homeostasis. SETD4+ cells generate newborn acinar cells in response to cerulein-induced pancreatitis in acinar compartments. Ablation of SETD4+ cells compromises regeneration of acinar cells, in contrast to controls. Our findings provide a new cellular narrative for pancreatic development, homeostasis and response to injury via a small SETD4+ cell population. Potential applications may act to preserve pancreatic function in case of pancreatic disease and/or damage.

scholarly journals Hlf Expression Marks Early Emergence of Hematopoietic Stem Cell Precursors With Adult Repopulating Potential and Fate

2021 ◽  
Vol 9 ◽  
Author(s):  
Wanbo Tang ◽  
Jian He ◽  
Tao Huang ◽  
Zhijie Bai ◽  
Chaojie Wang ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mouse Model ◽  
Hematopoietic Stem Cells ◽  
Fetal Liver ◽  
Lineage Tracing ◽  
Genetic Lineage ◽  
Hematopoietic Stem ◽  
Genetic Lineage Tracing

In the aorta-gonad-mesonephros (AGM) region of mouse embryos, pre-hematopoietic stem cells (pre-HSCs) are generated from rare and specialized hemogenic endothelial cells (HECs) via endothelial-to-hematopoietic transition, followed by maturation into bona fide hematopoietic stem cells (HSCs). As HECs also generate a lot of hematopoietic progenitors not fated to HSCs, powerful tools that are pre-HSC/HSC-specific become urgently critical. Here, using the gene knockin strategy, we firstly developed an Hlf-tdTomato reporter mouse model and detected Hlf-tdTomato expression exclusively in the hematopoietic cells including part of the immunophenotypic CD45– and CD45+ pre-HSCs in the embryonic day (E) 10.5 AGM region. By in vitro co-culture together with long-term transplantation assay stringent for HSC precursor identification, we further revealed that unlike the CD45– counterpart in which both Hlf-tdTomato-positive and negative sub-populations harbored HSC competence, the CD45+ E10.5 pre-HSCs existed exclusively in Hlf-tdTomato-positive cells. The result indicates that the cells should gain the expression of Hlf prior to or together with CD45 to give rise to functional HSCs. Furthermore, we constructed a novel Hlf-CreER mouse model and performed time-restricted genetic lineage tracing by a single dose induction at E9.5. We observed the labeling in E11.5 AGM precursors and their contribution to the immunophenotypic HSCs in fetal liver (FL). Importantly, these Hlf-labeled early cells contributed to and retained the size of the HSC pool in the bone marrow (BM), which continuously differentiated to maintain a balanced and long-term multi-lineage hematopoiesis in the adult. Therefore, we provided another valuable mouse model to specifically trace the fate of emerging HSCs during development.

scholarly journals Direct neuronal reprogramming by temporal identity factors

2021 ◽  
Author(s):  
Camille Boudreau-Pinsonneault ◽  
Awais Javed ◽  
Michel Fries ◽  
Pierre Mattar ◽  
Michel Cayouette
Keyword(s):  
Gene Expression ◽  
Expression System ◽  
Lineage Tracing ◽  
Developmental Competence ◽  
Rapid Screening ◽  
Mouse Retina ◽  
Genetic Lineage ◽  
Differentiated Cells ◽  
Temporal Identity

Temporal identity factors are sufficient to reprogram developmental competence of neural progenitors, but whether they could also reprogram the identity of fully differentiated cells is unknown. To address this question, we designed a conditional gene expression system combined with genetic lineage tracing that allows rapid screening of potential reprogramming factors in the mouse retina. Using this assay, we report that co-expression of the early temporal identity transcription factor Ikzf1, together with Ikzf4, another Ikaros family member, is sufficient to directly convert adult Muller glial cells into neuron-like cells in vivo, without inducing a proliferative progenitor state. scRNA-seq analysis shows that the reprogrammed cells share some transcriptional signatures with both cone photoreceptors and bipolar cells. Furthermore, we show that co-expression of Ikzf1 and Ikzf4 can reprogram mouse embryonic fibroblasts to induced neurons by remodeling chromatin and promoting a neuronal gene expression program. This work uncovers general neuronal reprogramming properties for temporal identity factors in differentiated cells, opening new opportunities for cell therapy development.

scholarly journals Unraveling the transcriptional networks that drive oligodendrocyte fate specification in Sonic hedgehog-responsive neocortical progenitors

2020 ◽  
Author(s):  
Caitlin C. Winkler ◽  
Luuli N. Tran ◽  
Ellyn P. Milan ◽  
Fernando García-Moreno ◽  
Santos J. Franco
Keyword(s):  
Sonic Hedgehog ◽  
Wild Type Mouse ◽  
Lineage Tracing ◽  
Human Embryos ◽  
Transcriptional Networks ◽  
Genetic Lineage ◽  
Gene Regulatory ◽  
Oligodendrocyte Precursor ◽  
Genetic Lineage Tracing ◽  
Developing Nervous System

In the developing nervous system, progenitors first generate neurons before making astrocytes and oligodendrocytes. We previously showed that increased Sonic hedgehog (Shh) signaling in dorsal forebrain progenitors is important for their production of oligodendrocytes as neurogenesis winds down. Here, we analyzed single-cell RNA sequencing datasets to better understand how Shh controls this neuron-to-oligodendrocyte switch in the neocortex. We first identified Shh-responding progenitors using a dataset in which Shh was overexpressed in the mouse dorsal forebrain. Pseudotime trajectory inferences revealed a subpopulation committed to the oligodendrocyte precursor cell (OPC) lineage. Genes upregulated along this lineage defined a pre-OPC state, as cells transitioned from progenitors to OPCs. Using several datasets from wild-type mouse and human embryos at different ages, we confirmed a pre-OPC state preceding OPC emergence during normal development. Finally, we show that pre-OPCs are enriched for a gene regulatory network involving the transcription factor Ascl1. Genetic lineage-tracing demonstrated Ascl1+ dorsal progenitors primarily make oligodendrocytes. We propose a model in which Shh shifts the balance between opposing transcriptional networks toward an Ascl1 lineage, thereby facilitating the switch between neurogenesis and oligodendrogenesis.

scholarly journals Genetic Lineage Tracing of Sca-1 + Cells Reveals Endothelial but Not Myogenic Contribution to the Murine Heart

Circulation ◽  
2018 ◽  
Vol 138 (25) ◽  
pp. 2931-2939 ◽  
Author(s):  
Ronald J. Vagnozzi ◽  
Michelle A. Sargent ◽  
Suh-Chin J. Lin ◽  
Nathan J. Palpant ◽  
Charles E. Murry ◽  
...  
Keyword(s):  
Lineage Tracing ◽  
Genetic Lineage ◽  
Genetic Lineage Tracing

scholarly journals Troy+ brain stem cells cycle through quiescence and regulate their number by sensing niche occupancy

2018 ◽  
Vol 115 (4) ◽  
pp. E610-E619 ◽  
Author(s):  
Onur Basak ◽  
Teresa G. Krieger ◽  
Mauro J. Muraro ◽  
Kay Wiebrands ◽  
Daniel E. Stange ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell Number ◽  
Lineage Tracing ◽  
Rapid Expansion ◽  
Molecular Signature ◽  
Genetic Lineage ◽  
Proliferating Cells ◽  
Self Renewal ◽  
Genetic Lineage Tracing

The adult mouse subependymal zone provides a niche for mammalian neural stem cells (NSCs). However, the molecular signature, self-renewal potential, and fate behavior of NSCs remain poorly defined. Here we propose a model in which the fate of active NSCs is coupled to the total number of neighboring NSCs in a shared niche. Using knock-in reporter alleles and single-cell RNA sequencing, we show that the Wnt target Tnfrsf19/Troy identifies both active and quiescent NSCs. Quantitative analysis of genetic lineage tracing of individual NSCs under homeostasis or in response to injury reveals rapid expansion of stem-cell number before some return to quiescence. This behavior is best explained by stochastic fate decisions, where stem-cell number within a shared niche fluctuates over time. Fate mapping proliferating cells using a Ki67iresCreER allele confirms that active NSCs reversibly return to quiescence, achieving long-term self-renewal. Our findings suggest a niche-based mechanism for the regulation of NSC fate and number.

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