scholarly journals Zebrafish pigment cells develop directly from persistent highly multipotent progenitors.

2021 ◽  
Author(s):  
Masataka Nikaido ◽  
Tatiana Subkhankulova ◽  
Leonid A. Uroshlev ◽  
Artem J. Kasianov ◽  
Karen Camargo Sosa ◽  
...  
Keyword(s):  
Pigment Cell ◽  
Transcriptional Profiling ◽  
Cell Types ◽  
Cell Development ◽  
Lineage Tracing ◽  
Pigment Cells ◽  
Multipotent Stem Cells ◽  
Multipotent Progenitors ◽  
Fate Restriction

Neural crest cells (NCCs) are highly multipotent stem cells. A long-standing controversy exists over the mechanism of NCC fate specification, specifically regarding the presence and potency of intermediate progenitors. The direct fate restriction (DFR) model, based on early in vivo clonal studies, hypothesised that intermediates are absent and that migrating cells maintain full multipotency. However, most authors favour progressive fate restriction (PFR) models, with fully multipotent early NCCs (ENCCs) transitioning to partially-restricted intermediates before committing to individual fates. Here, single cell transcriptional profiling of zebrafish pigment cell development leads to us proposing a Cyclical Fate Restriction mechanism of NCC development that reconciles the DFR and PFR models. Our clustering of single NCC Nanostring transcriptional profiles identifies only broadly multipotent intermediate states between ENCCs and differentiated melanocytes and iridophores. Leukocyte tyrosine kinase (Ltk) marks the multipotent progenitor and iridophores, consistent with biphasic ltk expression. Ltk inhibitor and constitutive activation studies support expression at an early multipotent stage, whilst lineage-tracing of ltk-expressing cells reveals their multipotency extends beyond pigment cell-types to neural fates. We conclude that pigment cell development does not involve a conventional PFR mechanism, but instead occurs directly and more dynamically from a broadly multipotent intermediate state.

scholarly journals Taking a Step Back: Insights into the Mechanisms Regulating Gut Epithelial Dedifferentiation

2021 ◽  
Vol 22 (13) ◽  
pp. 7043
Author(s):  
Shaida Ouladan ◽  
Alex Gregorieff
Keyword(s):  
Cell Fate ◽  
Hormonal Regulation ◽  
Transcriptional Profiling ◽  
Cell Types ◽  
Lineage Tracing ◽  
Intestinal Stem Cells ◽  
Physical Damage ◽  
Epithelial Regeneration ◽  
Gut Epithelium ◽  
Stem Cell Populations

Despite the environmental constraints imposed upon the intestinal epithelium, this tissue must perform essential functions such as nutrient absorption and hormonal regulation, while also acting as a critical barrier to the outside world. These functions depend on a variety of specialized cell types that are constantly renewed by a rapidly proliferating population of intestinal stem cells (ISCs) residing at the base of the crypts of Lieberkühn. The niche components and signals regulating crypt morphogenesis and maintenance of homeostatic ISCs have been intensely studied over the last decades. Increasingly, however, researchers are turning their attention to unraveling the mechanisms driving gut epithelial regeneration due to physical damage or infection. It is now well established that injury to the gut barrier triggers major cell fate changes, demonstrating the highly plastic nature of the gut epithelium. In particular, lineage tracing and transcriptional profiling experiments have uncovered several injury-induced stem-cell populations and molecular markers of the regenerative state. Despite the progress achieved in recent years, several questions remain unresolved, particularly regarding the mechanisms driving dedifferentiation of the gut epithelium. In this review, we summarize the latest studies, primarily from murine models, that define the regenerative processes governing the gut epithelium and discuss areas that will require more in-depth investigation.

scholarly journals CXCL12-CXCR4 chemokine signaling is essential for NK-cell development in adult mice

Blood ◽  
2011 ◽  
Vol 117 (2) ◽  
pp. 451-458 ◽  
Author(s):  
Mamiko Noda ◽  
Yoshiki Omatsu ◽  
Tatsuki Sugiyama ◽  
Shinya Oishi ◽  
Nobutaka Fujii ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Nk Cells ◽  
Nk Cell ◽  
Cell Development ◽  
Hematopoietic Stem ◽  
Adult Mice ◽  
Multipotent Progenitors ◽  
Chemokine Signaling ◽  
Chemokine Ligand

Abstract Natural killer (NK) cells are granular lymphocytes that are generated from hematopoietic stem cells and play vital roles in the innate immune response against tumors and viral infection. Generation of NK cells is known to require several cytokines, including interleukin-15 (IL-15) and Fms-like tyrosine kinase 3 ligand, but not IL-2 or IL-7. Here we investigated the in vivo role of CXC chemokine ligand-12 (CXCL12) and its primary receptor CXCR4 in NK-cell development. The numbers of NK cells appeared normal in embryos lacking CXCL12 or CXCR4; however, the numbers of functional NK cells were severely reduced in the bone marrow, spleen, and peripheral blood from adult CXCR4 conditionally deficient mice compared with control animals, probably resulting from cell-intrinsic CXCR4 deficiency. In culture, CXCL12 enhanced the generation of NK cells from lymphoid-primed multipotent progenitors and immature NK cells. In the bone marrow, expression of IL-15 mRNA was considerably higher in CXCL12-abundant reticular (CAR) cells than in other marrow cells, and most NK cells were in contact with the processes of CAR cells. Thus, CXCL12-CXCR4 chemokine signaling is essential for NK-cell development in adults, and CAR cells might function as a niche for NK cells in bone marrow.

scholarly journals Regulation of melanocyte development by ligand-dependent BMP signaling underlies oncogenic BMP signaling in melanoma

2019 ◽  
Author(s):  
Alec K. Gramann ◽  
Arvind M. Venkatesan ◽  
Melissa Guerin ◽  
Craig J. Ceol
Keyword(s):  
Neural Crest ◽  
Pigment Cell ◽  
Terminal Differentiation ◽  
Melanoma Cells ◽  
Cell Development ◽  
Bmp Signaling ◽  
Pigment Cells ◽  
Cell Type ◽  
Neural Crest Development ◽  
Direct Regulation

AbstractPreventing terminal differentiation is important in the development and progression of many cancers including melanoma. Recent identification of the BMP ligand GDF6 as a novel melanoma oncogene showed GDF6-activated BMP signaling suppresses differentiation of melanoma cells. Previous studies have identified roles for GDF6 orthologs during early embryonic and neural crest development, but have not identified direct regulation of melanocyte development by GDF6. Here, we investigate the BMP ligand gdf6a, a zebrafish ortholog of human GDF6, during the development of melanocytes from the neural crest. We establish that the loss of gdf6a or inhibition of BMP signaling during neural crest development disrupts normal pigment cell development, leading to an increase in the number of melanocytes and a corresponding decrease in iridophores, another neural crest-derived pigment cell type in zebrafish. This shift occurs as pigment cells arise from the neural crest and depends on mitfa, an ortholog of MITF, a key regulator of melanocyte development that is also targeted by oncogenic BMP signaling. Together, these results indicate that the oncogenic role ligand-dependent BMP signaling plays in suppressing differentiation in melanoma is a reiteration of its physiological roles during melanocyte development.

Common precursors for neural and mesectodermal derivatives in the cephalic neural crest

Development ◽  
1991 ◽  
Vol 112 (1) ◽  
pp. 301-305 ◽  
Author(s):  
A. Baroffio ◽  
E. Dupin ◽  
N.M. Le Douarin
Keyword(s):  
Neural Crest ◽  
Cell Types ◽  
Culture Conditions ◽  
Pigment Cells ◽  
Stem Cell Population ◽  
Multipotent Cells ◽  
Clonal Cultures ◽  
Vertebrate Embryos ◽  
Derivatives Of

The cephalic neural crest (NC) of vertebrate embryos yields a variety of cell types belonging to the neuronal, glial, melanocytic and mesectodermal lineages. Using clonal cultures of quail migrating cephalic NC cells, we demonstrated that neurons and glial cells of the peripheral nervous system can originate from the same progenitors as cartilage, one of the mesectodermal derivatives of the NC. Moreover, we obtained evidence that the migrating cephalic NC contains a few highly multipotent precursors that are common to neurons, glia, cartilage and pigment cells and which we interprete as representative of a stem cell population. In contrast, other NC cells, although provided with identical culture conditions, give rise to clones composed of only one or some of these cell types. These cells thus appear restricted in their developmental potentialities compared to multipotent cells. It is therefore proposed that, in vivo, the active proliferation of pluripotent NC cells during the migration process generates distinct subpopulations of cells that become progressively committed to different developmental fates.

scholarly journals Kinetics of adult hematopoietic stem cell differentiation in vivo

2018 ◽  
Vol 215 (11) ◽  
pp. 2815-2832 ◽  
Author(s):  
Samik Upadhaya ◽  
Catherine M. Sawai ◽  
Efthymia Papalexi ◽  
Ali Rashidfarrokhi ◽  
Geunhyo Jang ◽  
...  
Keyword(s):  
Stem Cell Differentiation ◽  
Cell Types ◽  
Lineage Tracing ◽  
Intermediate Cell ◽  
Hematopoietic Stem ◽  
Hematopoietic Stem Cell Differentiation ◽  
Kinetics Of ◽  
Kinetics In Vivo

Adult hematopoiesis has been studied in terms of progenitor differentiation potentials, whereas its kinetics in vivo is poorly understood. We combined inducible lineage tracing of endogenous adult hematopoietic stem cells (HSCs) with flow cytometry and single-cell RNA sequencing to characterize early steps of hematopoietic differentiation in the steady-state. Labeled cells, comprising primarily long-term HSCs and some short-term HSCs, produced megakaryocytic lineage progeny within 1 wk in a process that required only two to three cell divisions. Erythroid and myeloid progeny emerged simultaneously by 2 wk and included a progenitor population with expression features of both lineages. Myeloid progenitors at this stage showed diversification into granulocytic, monocytic, and dendritic cell types, and rare intermediate cell states could be detected. In contrast, lymphoid differentiation was virtually absent within the first 3 wk of tracing. These results show that continuous differentiation of HSCs rapidly produces major hematopoietic lineages and cell types and reveal fundamental kinetic differences between megakaryocytic, erythroid, myeloid, and lymphoid differentiation.

Transdifferentiation of pancreatic ductal cells to endocrine β-cells

2008 ◽  
Vol 36 (3) ◽  
pp. 353-356 ◽  
Author(s):  
Susan Bonner-Weir ◽  
Akari Inada ◽  
Shigeru Yatoh ◽  
Wan-Chun Li ◽  
Tandy Aye ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Duct Cell ◽  
Cell Types ◽  
Lineage Tracing ◽  
Β Cells ◽  
Partial Pancreatectomy ◽  
Pancreatic Cell ◽  
Ductal Cells ◽  
Pancreatic Ductal Cells

The regenerative process in the pancreas is of particular interest, since diabetes, whether Type 1 or Type 2, results from an inadequate amount of insulin-producing β-cells. Islet neogenesis, or the formation of new islets, seen as budding of hormone-positive cells from the ductal epithelium, has long been considered to be one of the mechanisms of normal islet growth after birth and in regeneration, and suggested the presence of pancreatic stem cells. Results from the rat regeneration model of partial pancreatectomy led us to hypothesize that differentiated pancreatic ductal cells were the pancreatic progenitors after birth, and that with replication they regressed to a less differentiated phenotype and then could differentiate to form new acini and islets. There are numerous supportive results for this hypothesis of neogenesis, including the ability of purified primary human ducts to form insulin-positive cells budding from ducts. However, to rigorously test this hypothesis, we took a direct approach of genetically marking ductal cells using CAII (carbonic anhydrase II) as a duct-cell-specific promoter to drive Cre recombinase in lineage-tracing experiments using the Cre-Lox system. We show that CAII-expressing pancreatic cells act as progenitors that give rise to both new islets and acini after birth and after injury (ductal ligation). This identification of a differentiated pancreatic cell type as an in vivo progenitor for all differentiated pancreatic cell types has implications for a potential expandable source for new islets for replenishment therapy for diabetes either in vivo or ex vivo.

scholarly journals Techniques for visualizing fibroblast-vessel interactions in the developing and adult CNS

2021 ◽  
Author(s):  
Hannah E Jones ◽  
Kelsey A Abrams ◽  
Julie A Siegenthaler
Keyword(s):  
Choroid Plexus ◽  
Transcriptional Profiling ◽  
Cell Types ◽  
Perivascular Spaces ◽  
Mouse Line ◽  
Whole Mount ◽  
Staining Methods ◽  
Proliferation Assays ◽  
Different Cell Types

Fibroblasts are found associated with blood vessels in various locations across the CNS: in the meninges, the choroid plexus, and in the parenchyma within perivascular spaces. CNS fibroblasts have been characterized using transcriptional profiling and a Col1a1-GFP mouse line used to identify CNS fibroblasts in vivo. However, current methods for visualizing CNS fibroblasts are lacking and, in particular, prevent adequate assessment of fibroblast-vessel interactions. Here, we describe methods for whole mount visualization of meningeal and choroid plexus fibroblasts, and optical tissue clearing methods for visualization of parenchymal vessel-associated fibroblasts. Importantly, these techniques can be combined with immunohistochemistry methods for labeling different cell types in the meninges and blood vasculature as well as EdU-based cell proliferation assays. These methods are ideal for visualization of vessel-fibroblast interactions in these CNS structures and provide significant improvement over traditional sectioning and staining methods. We expect these methods will advance studies of CNS fibroblast development and functions in homeostasis, injury, and disease.

scholarly journals IL7R⍺ is required for hematopoietic stem cell reconstitution of tissue-resident lymphoid cells

2021 ◽  
Author(s):  
Atesh K Worthington ◽  
Taylor S Cool ◽  
Donna M Poscablo ◽  
Adeel Hussaini ◽  
Anna E Beaudin ◽  
...  
Keyword(s):  
Cell Types ◽  
Lineage Tracing ◽  
Lymphoid Cells ◽  
Lymphoid Tissues ◽  
Hematopoietic Stem ◽  
Functional Roles ◽  
Reciprocal Transplants ◽  
B1a Cells

Traditional, adult-derived lymphocytes that circulate provide adaptive immunity to infection and pathogens. However, subsets of lymphoid cells are also found in non-lymphoid tissues and are called tissue-resident lymphoid cells (TLCs). TLCs encompass a wide array of cell types that span the spectrum of innate-to-adaptive immune function. Unlike traditional lymphocytes that are continuously generated from hematopoietic stem cells (HSCs), many TLCs are of fetal origin and poorly generated from adult HSCs. Here, we sought to understand the development of murine TLCs across multiple tissues and therefore probed the roles of Flk2 and IL7R⍺, two cytokine receptors with known roles in traditional lymphopoiesis. Using Flk2- and Il7r-Cre lineage tracing models, we found that peritoneal B1a cells, splenic marginal zone B (MZB) cells, lung ILC2s and regulatory T cells (Tregs) were highly labeled in both models. Despite this high labeling, highly quantitative, in vivo functional approaches showed that the loss of Flk2 minimally affected the generation of these cells in situ. In contrast, the loss of IL7R⍺, or combined deletion of Flk2 and IL7R⍺, dramatically reduced the cell numbers of B1a cells, MZBs, ILC2s, and Tregs both in situ and upon transplantation, indicating an intrinsic and more essential role for IL7Rα. Surprisingly, reciprocal transplants of WT HSCs showed that an IL7Rα-/- environment selectively impaired reconstitution of TLCs when compared to TLC numbers in situ. Taken together, our data revealed functional roles of Flk2 and IL7Rα in the establishment of tissue-resident lymphoid cells.

scholarly journals The MITF paralog tfec is required in neural crest development for fate specification of the iridophore lineage from a multipotent pigment cell progenitor

PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0244794 ◽  
Author(s):  
Kleio Petratou ◽  
Samantha A. Spencer ◽  
Robert N. Kelsh ◽  
James A. Lister
Keyword(s):  
Neural Crest ◽  
Regulatory Network ◽  
Pigment Cell ◽  
Cell Types ◽  
Cellular Mechanisms ◽  
Cell Fates ◽  
Master Regulator ◽  
Fate Specification ◽  
Multipotent Progenitors ◽  
Gene Regulatory

Understanding how fate specification of distinct cell-types from multipotent progenitors occurs is a fundamental question in embryology. Neural crest stem cells (NCSCs) generate extraordinarily diverse derivatives, including multiple neural, skeletogenic and pigment cell fates. Key transcription factors and extracellular signals specifying NCSC lineages remain to be identified, and we have only a little idea of how and when they function together to control fate. Zebrafish have three neural crest-derived pigment cell types, black melanocytes, light-reflecting iridophores and yellow xanthophores, which offer a powerful model for studying the molecular and cellular mechanisms of fate segregation. Mitfa has been identified as the master regulator of melanocyte fate. Here, we show that an Mitf-related transcription factor, Tfec, functions as master regulator of the iridophore fate. Surprisingly, our phenotypic analysis of tfec mutants demonstrates that Tfec also functions in the initial specification of all three pigment cell-types, although the melanocyte and xanthophore lineages recover later. We show that Mitfa represses tfec expression, revealing a likely mechanism contributing to the decision between melanocyte and iridophore fate. Our data are consistent with the long-standing proposal of a tripotent progenitor restricted to pigment cell fates. Moreover, we investigate activation, maintenance and function of tfec in multipotent NCSCs, demonstrating for the first time its role in the gene regulatory network forming and maintaining early neural crest cells. In summary, we build on our previous work to characterise the gene regulatory network governing iridophore development, establishing Tfec as the master regulator driving iridophore specification from multipotent progenitors, while shedding light on possible cellular mechanisms of progressive fate restriction.

Exploring HIV latency using transcription profiling

2017 ◽  
Vol 38 (3) ◽  
pp. 137
Author(s):  
Sushama Telwatte ◽  
Steven A Yukl
Keyword(s):  
Transcriptional Profiling ◽  
Cell Types ◽  
Hiv Latency ◽  
Dna Viruses ◽  
Major Barrier ◽  
Hiv Transcription ◽  
Latently Infected ◽  
Infected Cells ◽  
Mechanisms Of Persistence

The major barrier to a cure for HIV is the existence of reservoirs consisting predominantly of latently infected CD4+ T cells, which do not produce virus constitutively but can be induced to produce infectious virus on activation. HIV latency research has largely focused on peripheral blood, yet most HIV-infected cells reside in tissues, especially the gut, where differences in drug penetration, cell types, and immune responses may impact mechanisms of persistence. Exploring the differences between the gut and the blood in transcriptional blocks may reveal fundamental insights into mechanisms that contribute to HIV latency. Our novel transcriptional profiling assays enable us to determine where blocks to HIV transcription occur in various tissues and the magnitude of their contribution. These assays could also be adapted to investigate latency established by other retroviridae or even DNA viruses such as herpesviridae with a view to pinpointing mechanisms underlying latency in vivo and ultimately contribute to designing a cure.

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