scholarly journals Diverse Epithelial Cell Populations Contribute to Regeneration of Secretory Units in Injured Salivary Glands

2020 ◽  
Author(s):  
Ninche Ninche ◽  
Mingyu Kwak ◽  
Soosan Ghazizadeh
Keyword(s):  
Stem Cells ◽  
Salivary Glands ◽  
De Novo ◽  
Cell Types ◽  
Myoepithelial Cells ◽  
Lineage Tracing ◽  
Secretory Cells ◽  
Cell Populations ◽  
Cellular Plasticity ◽  
Ductal Cells

ABSTRACTSalivary glands exert exocrine secretory function to provide saliva for lubrication and protection of the oral cavity. Its epithelium consists of several differentiated cell types including acinar, ductal and myoepithelial cells that are maintained in a lineage-restricted manner during homeostasis or after mild injuries. Glandular regeneration following a near complete loss of secretory cells, however, may involve cellular plasticity, although the mechanism and extent of such plasticity remain unclear. Here, by combining lineage-tracing experiments with a model of severe glandular injury in the mouse submandibular gland, we show that de novo formation of secretory units involves induction of cellular plasticity in multiple non-acinar cell populations. Fate-mapping analysis revealed that although ductal stem cells marked by cytokeratin K14 and Axin2 undergo a multipotency switch, they do not make a significant contribution to acinar regeneration. Intriguingly, more than 80% of regenerated acini derive from differentiated cells including myoepithelial and ductal cells that dedifferentiate to a progenitor-like state before redifferentiation to acinar cells. The potential of diverse cell populations serving as a reserve source for acini widens the therapeutic options for hyposalivation.SummarySalivary glands rely in recruitment of committed and fully differentiated cell populations as well as stem cells to ensure rapid regeneration and recovery of secretory cells.

scholarly journals Diverse epithelial cell populations contribute to the regeneration of secretory units in injured salivary glands

Development ◽  
2020 ◽  
Vol 147 (19) ◽  
pp. dev192807
Author(s):  
Ninche Ninche ◽  
Mingyu Kwak ◽  
Soosan Ghazizadeh
Keyword(s):  
Salivary Glands ◽  
De Novo ◽  
Cell Types ◽  
Myoepithelial Cells ◽  
Lineage Tracing ◽  
Secretory Cells ◽  
Cell Populations ◽  
Cellular Plasticity ◽  
Ductal Cells ◽  
Differentiated Cells

ABSTRACTSalivary glands exert exocrine secretory function to provide saliva for lubrication and protection of the oral cavity. Its epithelium consists of several differentiated cell types, including acinar, ductal and myoepithelial cells, that are maintained in a lineage-restricted manner during homeostasis or after mild injuries. Glandular regeneration following a near complete loss of secretory cells, however, may involve cellular plasticity, although the mechanism and extent of such plasticity remain unclear. Here, by combining lineage-tracing experiments with a model of severe glandular injury in the mouse submandibular gland, we show that de novo formation of acini involves induction of cellular plasticity in multiple non-acinar cell populations. Fate-mapping analysis revealed that, although ductal stem cells marked by cytokeratin K14 and Axin2 undergo a multipotency switch, they do not make a significant contribution to acinar regeneration. Intriguingly, more than 80% of regenerated acini derive from differentiated cells, including myoepithelial and ductal cells, that appear to dedifferentiate to a progenitor-like state before re-differentiation into acinar cells. The potential of diverse cell populations serving as a reserve source for acini widens the therapeutic options for hyposalivation.

scholarly journals Signaling Control of Mucociliary Epithelia: Stem Cells, Cell Fates, and the Plasticity of Cell Identity in Development and Disease

2021 ◽  
pp. 1-18
Author(s):  
Peter Walentek
Keyword(s):  
Stem Cells ◽  
Mucociliary Clearance ◽  
Cell Types ◽  
Secretory Cells ◽  
Chronic Obstructive ◽  
Cell Identity ◽  
Obstructive Pulmonary Disease ◽  
Congenital Diseases ◽  
Inhaled Particles ◽  
Mucociliary Epithelia

Mucociliary epithelia are composed of multiciliated, secretory, and stem cells and line various organs in vertebrates such as the respiratory tract. By means of mucociliary clearance, those epithelia provide a first line of defense against inhaled particles and pathogens. Mucociliary clearance relies on the correct composition of cell types, that is, the proper balance of ciliated and secretory cells. A failure to generate and to maintain correct cell type composition and function results in impaired clearance and high risk to infections, such as in congenital diseases (e.g., ciliopathies) as well as in acquired diseases, including asthma, chronic obstructive pulmonary disease (COPD), and idiopathic pulmonary fibrosis (IPF). While it remains incompletely resolved how precisely cell types are specified and maintained in development and disease, many studies have revealed important mechanisms regarding the signaling control in mucociliary cell types in various species. Those studies not only provided insights into the signaling contribution to organ development and regeneration but also highlighted the remarkable plasticity of cell identity encountered in mucociliary maintenance, including frequent trans-differentiation events during homeostasis and specifically in disease. This review will summarize major findings and provide perspectives regarding the future of mucociliary research and the treatment of chronic airway diseases associated with tissue remodeling.

scholarly journals Definitive Hematopoietic Stem Cells Minimally Contribute to Embryonic Hematopoiesis

2021 ◽  
Author(s):  
Bianca A Ulloa ◽  
Samima S Habbsa ◽  
Kathryn S Potts ◽  
Alana Lewis ◽  
Mia McKinstry ◽  
...  
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
De Novo ◽  
Marker Gene ◽  
Lineage Tracing ◽  
Hematopoietic Stem ◽  
Functional Potential ◽  
Injury Model ◽  
Rare Cells

Hematopoietic stem cells (HSCs) are rare cells that arise in the embryo and sustain adult hematopoiesis. Although the functional potential of nascent HSCs is detectable by transplantation, their native contribution during development is unknown, in part due to the overlapping genesis and marker gene expression with other embryonic blood progenitors. Using single cell transcriptomics, we defined gene signatures that distinguish nascent HSCs from embryonic blood progenitors. Applying a new lineage tracing approach, we selectively tracked HSC output in situ and discovered significantly delayed lymphomyeloid contribution. Using a novel inducible HSC injury model, we demonstrated a negligible impact on larval lymphomyelopoiesis following HSC depletion. HSCs are not merely dormant at this developmental stage as they showed robust regeneration after injury. Combined, our findings illuminate that nascent HSCs self-renew but display differentiation latency, while HSC-independent embryonic progenitors sustain developmental hematopoiesis. Understanding the differences among embryonic HSC and progenitor populations will guide improved de novo generation and expansion of functional HSCs.

scholarly journals Cells expressing PAX8 are the main source of homeostatic regeneration of adult mouse endometrial epithelium and give rise to serous endometrial carcinoma

2020 ◽  
Vol 13 (10) ◽  
pp. dmm047035
Author(s):  
Dah-Jiun Fu ◽  
Andrea J. De Micheli ◽  
Mallikarjun Bidarimath ◽  
Lora H. Ellenson ◽  
Benjamin D. Cosgrove ◽  
...  
Keyword(s):  
Stem Cells ◽  
Epithelial Cells ◽  
Endometrial Carcinoma ◽  
Marrow Cell ◽  
Cell Types ◽  
Lineage Tracing ◽  
Cell Of Origin ◽  
Mouse Uterus ◽  
Endometrial Epithelium

ABSTRACTHumans and mice have cyclical regeneration of the endometrial epithelium. It is expected that such regeneration is ensured by tissue stem cells, but their location and hierarchy remain debatable. A number of recent studies have suggested the presence of stem cells in the mouse endometrial epithelium. At the same time, it has been reported that this tissue can be regenerated by stem cells of stromal/mesenchymal or bone marrow cell origin. Here, we describe a single-cell transcriptomic atlas of the main cell types of the mouse uterus and epithelial subset transcriptome and evaluate the contribution of epithelial cells expressing the transcription factor PAX8 to the homeostatic regeneration and malignant transformation of adult endometrial epithelium. According to lineage tracing, PAX8+ epithelial cells are responsible for long-term maintenance of both luminal and glandular epithelium. Furthermore, multicolor tracing shows that individual glands and contiguous areas of luminal epithelium are formed by clonal cell expansion. Inactivation of the tumor suppressor genes Trp53 and Rb1 in PAX8+ cells, but not in FOXJ1+ cells, leads to the formation of neoplasms with features of serous endometrial carcinoma, one of the most aggressive types of human endometrial malignancies. Taken together, our results show that the progeny of single PAX8+ cells represents the main source of regeneration of the adult endometrial epithelium. They also provide direct experimental genetic evidence for the key roles of the P53 and RB pathways in the pathogenesis of serous endometrial carcinoma and suggest that PAX8+ cells represent the cell of origin of this neoplasm.

scholarly journals Aldehyde Dehydrogenases: Not Just Markers, but Functional Regulators of Stem Cells

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Giuseppe Vassalli
Keyword(s):  
Stem Cells ◽  
Molecular Mechanisms ◽  
Cell Types ◽  
Cellular Function ◽  
Stem Cell Marker ◽  
Cell Populations ◽  
Aldh Activity ◽  
Cellular Functions ◽  
Stem And Progenitor Cells

Aldehyde dehydrogenase (ALDH) is a superfamily of enzymes that detoxify a variety of endogenous and exogenous aldehydes and are required for the biosynthesis of retinoic acid (RA) and other molecular regulators of cellular function. Over the past decade, high ALDH activity has been increasingly used as a selectable marker for normal cell populations enriched in stem and progenitor cells, as well as for cell populations from cancer tissues enriched in tumor-initiating stem-like cells. Mounting evidence suggests that ALDH not only may be used as a marker for stem cells but also may well regulate cellular functions related to self-renewal, expansion, differentiation, and resistance to drugs and radiation. ALDH exerts its functional actions partly through RA biosynthesis, as all-trans RA reverses the functional effects of pharmacological inhibition or genetic suppression of ALDH activity in many cell types in vitro. There is substantial evidence to suggest that the role of ALDH as a stem cell marker comes down to the specific isoform(s) expressed in a particular tissue. Much emphasis has been placed on the ALDH1A1 and ALDH1A3 members of the ALDH1 family of cytosolic enzymes required for RA biosynthesis. ALDH1A1 and ALDH1A3 regulate cellular function in both normal stem cells and tumor-initiating stem-like cells, promoting tumor growth and resistance to drugs and radiation. An improved understanding of the molecular mechanisms by which ALDH regulates cellular function will likely open new avenues in many fields, especially in tissue regeneration and oncology.

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.

Quantitative Imaging of Femoral Bone Marrow Microenvironments Reveals a Heterogenous Distribution of Hematopoietic Stem and Progenitor Cells.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 1455-1455
Author(s):  
Cesar Nombela-Arrieta ◽  
Brendan Harley ◽  
Gregory Pivarnik ◽  
John E Mahoney ◽  
Elena Levantini ◽  
...  
Keyword(s):  
Stem Cells ◽  
B Cells ◽  
Cell Biology ◽  
Conflicts Of Interest ◽  
Statistical Significance ◽  
Quantitative Imaging ◽  
Cell Types ◽  
Immunofluorescent Staining ◽  
Cell Populations ◽  
Hematopoietic Stem

Abstract Abstract 1455 Poster Board I-478 Sustained production of all mature blood cell types relies on the continuous proliferation and differentiation of a rare population of self-renewing, multipotent hematopoietic stem cells (HSCs). HSC maintenance and lineage differentiation are thought to be regulated by spatially confined niches, defined by cellular components, soluble regulators, and the extracellular matrix immediately surrounding stem cells. Identification of these microenvironments in which endogenous and transferred HSCs reside within the BM is a major challenge in stem cell biology with relevant clinical implications. Yet the extreme rarity of HSCs, their dynamic nature, and the lack of specific markers to identify them, have precluded an accurate definition of HSC niches to date. Quantitative imaging technologies such as Laser Scanning Cytometry (LSC) are designed for the automated analysis of large cell numbers at a single cell level with high resolution while preserving the morphological information lost in flow cytometry, therefore providing data of statistical significance even for rare cell populations such as HSCs. We have employed LSC to analyze the localization of both adoptively transferred and endogenous hematopoietic stem and progenitor cell (HSPC) populations inside whole longitudinal sections of murine femoral BM cavities. Our results indicate that, as previously suggested, purified HSPC (Lin−c-kit+Sca-1+) significantly accumulate in endosteal regions (ER) of BM cavities (within 100μm of inner bone surface) upon transplantation. Nevertheless, analysis of sufficient numbers of more differentiated cell subsets (Lin−c-kit+Sca-1− progenitors, pro B cells and mature B cells) indicated that these areas serve as homing sites for most hematopoietic cells, highlighting the limitations of any conclusions drawn on HSC niche identity from studies performed with transferred HSPC populations. Immunofluorescent staining of endogenous cell populations revealed a gradient in distribution of early hematopoietic progenitors (c-kit+), which accumulated in but were not restricted to ER regions. Of note, a vast majority (>80%) of HSPC (Bmi-GFPhic-kit+, or Lin−c-kit+Sca-1+),were found inside ER, although not directly adjacent to endosteal surfaces. Our studies define endosteal areas as tissue regions where HSPC reside in close proximity, but not necessarily in direct contact with a dense vascular network, osteoblastic cells and other potential niche cell types and growth factors currently under investigation. Disclosures No relevant conflicts of interest to declare.

scholarly journals Mouse telomerase reverse transcriptase (mTert) expression marks slowly cycling intestinal stem cells

2010 ◽  
Vol 108 (1) ◽  
pp. 179-184 ◽  
Author(s):  
Robert K. Montgomery ◽  
Diana L. Carlone ◽  
Camilla A. Richmond ◽  
Loredana Farilla ◽  
Mariette E. G. Kranendonk ◽  
...  
Keyword(s):  
Stem Cells ◽  
Reverse Transcriptase ◽  
Tissue Injury ◽  
Cell Types ◽  
Lineage Tracing ◽  
Intestinal Stem Cells ◽  
Intestinal Cell ◽  
Stem Cell Population ◽  
Telomerase Reverse Transcriptase

The intestinal epithelium is maintained by a population of rapidly cycling (Lgr5+) intestinal stem cells (ISCs). It has been postulated, however, that slowly cycling ISCs must also be present in the intestine to protect the genome from accumulating deleterious mutations and to allow for a response to tissue injury. Here, we identify a subpopulation of slowly cycling ISCs marked by mouse telomerase reverse transcriptase (mTert) expression that can give rise to Lgr5+ cells. mTert-expressing cells distribute in a pattern along the crypt–villus axis similar to long-term label-retaining cells (LRCs) and are resistant to tissue injury. Lineage-tracing studies demonstrate that mTert+ cells give rise to all differentiated intestinal cell types, persist long term, and contribute to the regenerative response following injury. Consistent with other highly regenerative tissues, our results demonstrate that a slowly cycling stem cell population exists within the intestine.

scholarly journals A Single-Cell Atlas and Lineage Analysis of the Adult Drosophila Ovary

2019 ◽  
Author(s):  
Katja Rust ◽  
Lauren Byrnes ◽  
Kevin Shengyang Yu ◽  
Jason S. Park ◽  
Julie B. Sneddon ◽  
...  
Keyword(s):  
Stem Cells ◽  
Single Cell ◽  
Cell Types ◽  
Somatic Tissue ◽  
Lineage Tracing ◽  
Major Cell Type ◽  
Follicle Stem Cells ◽  
Drosophila Ovary ◽  
Adult Drosophila ◽  
Lineage Analysis

AbstractThe Drosophila ovary is a widely used model for germ cell and somatic tissue biology. We have used single-cell RNA-sequencing to build a comprehensive cell atlas of the adult Drosophila ovary containing unique transcriptional profiles for every major cell type in the ovary, including the germline and follicle stem cells. Using this atlas we identify novel tools for identification and manipulation of known and novel cell types and perform lineage tracing to test cellular relationships of previously unknown cell types. By this we discovered a new form of cellular plasticity in which inner germarial sheath cells convert to follicle stem cells in response to starvation.Graphical Abstract

scholarly journals Origin of Myofibroblasts in Lung Fibrosis

2020 ◽  
Vol 1 (4) ◽  
pp. 155-162
Author(s):  
CF Hung
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Epithelial Cells ◽  
Lung Fibrosis ◽  
Cell Types ◽  
Mesenchymal Cells ◽  
Lineage Tracing ◽  
Alveolar Epithelial Cells ◽  
Multiple Sources ◽  
Alveolar Epithelial

Abstract Purpose of Review In this brief review, we will highlight important observational and experimental data in the literature that address the origin of scar-forming cells in lung fibrosis. Recent Findings Several cellular sources of activated scar-forming cells (myofibroblasts) have been postulated including alveolar epithelial cells; circulating fibrocytes; and lung stromal cell subpopulations including resident fibroblasts, pericytes, and resident mesenchymal stem cells. Recent advances in lineage-tracing models, however, fail to provide experimental evidence for epithelial and fibrocyte origins of lung myofibroblasts. Resident mesenchymal cells of the lung, which include various cell types including resident fibroblasts, pericytes, and resident mesenchymal stem cells, appear to be important sources of myofibroblasts in murine models of lung injury and fibrosis. Summary Lung myofibroblasts likely originate from multiple sources of lung-resident mesenchymal cells. Their relative contributions may vary depending on the type of injury. Although lineage-tracing experiments have failed to show significant contribution from epithelial cells or fibrocytes, they may play important functional roles in myofibroblast activation through paracrine signaling.

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