scholarly journals Neonatal annulus fibrosus regeneration occurs via recruitment and proliferation of Scleraxis-lineage cells

2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Olivia M. Torre ◽  
Victoria Mroz ◽  
Anthony R. Martinez Benitez ◽  
Alice H. Huang ◽  
James C. Iatridis
Keyword(s):  
Sonic Hedgehog ◽  
Annulus Fibrosus ◽  
Type I Collagen ◽  
Cellular Mechanism ◽  
Functional Restoration ◽  
Lineage Tracing ◽  
Genetic Lineage ◽  
Type I ◽  
Fate Map ◽  
Genetic Lineage Tracing

AbstractIntervertebral disc (IVD) injuries are a cause of degenerative changes in adults which can lead to back pain, a leading cause of disability. We developed a model of neonatal IVD regeneration with full functional restoration and investigate the cellular dynamics underlying this unique healing response. We employed genetic lineage tracing in mice using Scleraxis (Scx) and Sonic hedgehog (Shh) to fate-map annulus fibrosus (AF) and nucleus pulposus (NP) cells, respectively. Results indicate functional AF regeneration after severe herniation injury occurs in neonates and not adults. AF regeneration is mediated by Scx-lineage cells that lose ScxGFP expression and adopt a stem/progenitor phenotype (Sca-1, days 3–14), proliferate, and then redifferentiate towards type I collagen producing, ScxGFP+ annulocytes at day 56. Non Scx-lineage cells were also transiently observed during neonatal repair, including Shh-lineage cells, macrophages, and myofibroblasts; however, these populations were no longer detected by day 56 when annulocytes redifferentiate. Overall, repair did not occur in adults. These results identify an exciting cellular mechanism of neonatal AF regeneration that is predominantly driven by Scx-lineage annulocytes.

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 Progenitor Cell Expansion and Organ Size of Mouse Adrenal Is Regulated by Sonic Hedgehog

Endocrinology ◽  
2010 ◽  
Vol 151 (3) ◽  
pp. 1119-1128 ◽  
Author(s):  
Chen-Che Jeff Huang ◽  
Shinichi Miyagawa ◽  
Daisuke Matsumaru ◽  
Keith L. Parker ◽  
Humphrey Hung-Chang Yao
Keyword(s):  
Sonic Hedgehog ◽  
Progenitor Cell ◽  
Adult Life ◽  
Lineage Tracing ◽  
Genetic Lineage ◽  
Plasma Acth ◽  
Steroidogenic Factor 1 ◽  
Genetic Lineage Tracing ◽  
High Level

The adrenal capsule is postulated to harbor stem/progenitor cells, the progenies of which contribute to the growth of adrenocortex. We discovered that cells in the adrenal capsule are positive for Ptch1 and Gli1, genes indicative of responsiveness to the stimulation of Hedgehog (Hh) ligands. On the other hand, Sonic hedgehog (Shh), one of the mammalian Hh ligands, is expressed in the adrenocortex underneath the adrenal capsule, possibly acting upon the Hh-Responsive capsule. To investigate the functional significance of Shh in adrenal growth, we ablated Shh in an adrenocortex-specific manner using the Steroidogenic factor 1-Cre mouse. Loss of Shh in the adrenocortex led to reduced proliferation of capsular cells and a 50–75% reduction in adrenocortex thickness and adrenal size. The remaining adrenocortex underwent proper zonation and was able to synthesize steroids, indicating that Shh is dispensable for differentiation of adrenocortex. When these animals reached adulthood, their adrenocortex did not undergo compensatory growth in response to a high level of plasma ACTH, and the size of the adrenal remained significantly smaller than the control adrenal. Using a genetic lineage-tracing model, we further demonstrated that the Hh-responding cells in the adrenal capsule migrated centripetally into the adrenocortex. Our results not only provide the genetic evidence to support that the adrenal capsule contributes to the growth of adrenocortex in both fetal and adult life but also identify a novel role of Shh in this process.

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 Fibroblast-specific protein 1 identifies an inflammatory subpopulation of macrophages in the liver

2010 ◽  
Vol 108 (1) ◽  
pp. 308-313 ◽  
Author(s):  
Christoph H. Österreicher ◽  
Melitta Penz-Österreicher ◽  
Sergei I. Grivennikov ◽  
Monica Guma ◽  
Ekaterina K. Koltsova ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Liver Disease ◽  
Liver Injury ◽  
Specific Protein ◽  
Lineage Tracing ◽  
Genetic Lineage ◽  
Type I ◽  
Mesenchymal Transition ◽  
Specific Subset ◽  
Experimental Liver

Cirrhosis is the end result of chronic liver disease. Hepatic stellate cells (HSC) are believed to be the major source of collagen-producing myofibroblasts in cirrhotic livers. Portal fibroblasts, bone marrow-derived cells, and epithelial to mesenchymal transition (EMT) might also contribute to the myofibroblast population in damaged livers. Fibroblast-specific protein 1 (FSP1, also called S100A4) is considered a marker of fibroblasts in different organs undergoing tissue remodeling and is used to identify fibroblasts derived from EMT in several organs including the liver. The aim of this study was to characterize FSP1-positive cells in human and experimental liver disease. FSP1-positive cells were increased in human and mouse experimental liver injury including liver cancer. However, FSP1 was not expressed by HSC or type I collagen-producing fibroblasts. Likewise, FSP1-positive cells did not express classical myofibroblast markers, including αSMA and desmin, and were not myofibroblast precursors in injured livers as evaluated by genetic lineage tracing experiments. Surprisingly, FSP1-positive cells expressed F4/80 and other markers of the myeloid-monocytic lineage as evaluated by double immunofluorescence staining, cell fate tracking, flow cytometry, and transcriptional profiling. Similar results were obtained for bone marrow-derived and peritoneal macrophages. FSP1-positive cells were characterized by increased expression of COX2, osteopontin, inflammatory cytokines, and chemokines but reduced expression of MMP3 and TIMP3 compared with Kupffer cells/macrophages. These findings suggest that FSP1 is a marker of a specific subset of inflammatory macrophages in liver injury, fibrosis, and cancer.

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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