1
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Keister BD, Mesa KR, Blagoev KB. Apoptotic cells may drive cell death in hair follicles during their regression cycle. Oncotarget 2023; 14:893-899. [PMID: 37861373 PMCID: PMC10588663 DOI: 10.18632/oncotarget.28529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 09/21/2023] [Indexed: 10/21/2023] Open
Abstract
Intravital microscopy in live mice has shown that the elimination of epithelial cells during hair follicle regression involves supra-basal cell differentiation and basal cell apoptosis through synergistic action of TGF-β (transforming growth factor) and mesenchymal-epithelial interactions. In this process the basal epithelial cells are not internally committed to death and the mesenchymal dermal papilla (DP) plays essential role in death induction. Because the DP cells are not necessary for completion of the cycle but only for its initiation it is still an open question what is the mechanism leading to the propagation of apoptosis towards the regenerative stem cell population. Here, we use a quantitative analysis of the length of hair follicles during their regression cycle. The data are consistent with a propagation mechanism driven by apoptotic cells inducing apoptosis in their neighboring cells. The observation that the apoptosis slows down as the apoptotic front approaches the stem cells at the end of the follicle is consistent with a gradient of a pro-survival signal sent by these stem cells. An experiment that can falsify this mechanism is proposed.
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Affiliation(s)
- Bradley D. Keister
- National Science Foundation, Physics Division, Alexandria, VA 22230, USA
| | - Kailin R. Mesa
- The Jane Coffin Childs Memorial Fund for Medical Research, New Haven, CT 06520, USA
- Department of Genetics and Dermatology, Yale Stem Cell Center, Yale Cancer Center, Yale School of Medicine, New Haven, CT 06510, USA
| | - Krastan B. Blagoev
- National Science Foundation, Physics Division, Alexandria, VA 22230, USA
- Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA
- Institute of Molecular Biology, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria
- Institut Curie, PSL Research University, Sorbonne Université, CNRS UMR3664, Laboratoire Dynamique du Noyau, Paris 75005, France
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2
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Mesa KR, O’Connor KA, Ng C, Salvatore SP, Littman DR. Niche-specific macrophage loss promotes skin capillary aging. bioRxiv 2023:2023.08.25.554832. [PMID: 37662387 PMCID: PMC10473701 DOI: 10.1101/2023.08.25.554832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
All mammalian organs depend upon resident macrophage populations to coordinate repair processes and facilitate tissue-specific functions1-3. Recent work has established that functionally distinct macrophage populations reside in discrete tissue niches and are replenished through some combination of local proliferation and monocyte recruitment4,5. Moreover, decline in macrophage abundance and function in tissues has been shown to contribute to many age-associated pathologies, such as atherosclerosis, cancer, and neurodegeneration6-8. Despite these advances, the cellular mechanisms that coordinate macrophage organization and replenishment within an aging tissue niche remain largely unknown. Here we show that capillary-associated macrophages (CAMs) are selectively lost over time, which contributes to impaired vascular repair and tissue perfusion in older mice. To investigate resident macrophage behavior in vivo, we have employed intravital two-photon microscopy to non-invasively image in live mice the skin capillary plexus, a spatially well-defined model of niche aging that undergoes rarefication and functional decline with age. We find that CAMs are lost with age at a rate that outpaces that of capillary loss, leading to the progressive accumulation of capillary niches without an associated macrophage in both mice and humans. Phagocytic activity of CAMs was locally required to repair obstructed capillary blood flow, leaving macrophage-less niches selectively vulnerable to both homeostatic and injury-induced loss in blood flow. Our work demonstrates that homeostatic renewal of resident macrophages is not as finely tuned as has been previously suggested9-11. Specifically, we found that neighboring macrophages do not proliferate or reorganize sufficiently to maintain an optimal population across the skin capillary niche in the absence of additional cues from acute tissue damage or increased abundance of growth factors, such as colony stimulating factor 1 (CSF1). Such limitations in homeostatic renewal and organization of various niche-resident cell types are potentially early contributors to tissue aging, which may provide novel opportunities for future therapeutic interventions.
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Affiliation(s)
- Kailin R. Mesa
- Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA
| | - Kevin A. O’Connor
- Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA
| | - Charles Ng
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York-Presbyterian Hospital, New York, NY 10021, USA
| | - Steven P. Salvatore
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York-Presbyterian Hospital, New York, NY 10021, USA
| | - Dan R. Littman
- Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA
- Perlmutter Cancer Center, New York University Langone Health, New York, NY 10016, USA
- Howard Hughes Medical Institute, New York, NY 10016, USA
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3
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Kedmi R, Najar TA, Mesa KR, Grayson A, Kroehling L, Hao Y, Hao S, Pokrovskii M, Xu M, Talbot J, Wang J, Germino J, Lareau CA, Satpathy AT, Anderson MS, Laufer TM, Aifantis I, Bartleson JM, Allen PM, Paidassi H, Gardner JM, Stoeckius M, Littman DR. A RORγt + cell instructs gut microbiota-specific T reg cell differentiation. Nature 2022; 610:737-743. [PMID: 36071167 PMCID: PMC9908423 DOI: 10.1038/s41586-022-05089-y] [Citation(s) in RCA: 70] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 07/08/2022] [Indexed: 01/19/2023]
Abstract
The mutualistic relationship of gut-resident microbiota and the host immune system promotes homeostasis that ensures maintenance of the microbial community and of a largely non-aggressive immune cell compartment1,2. The consequences of disturbing this balance include proximal inflammatory conditions, such as Crohn's disease, and systemic illnesses. This equilibrium is achieved in part through the induction of both effector and suppressor arms of the adaptive immune system. Helicobacter species induce T regulatory (Treg) and T follicular helper (TFH) cells under homeostatic conditions, but induce inflammatory T helper 17 (TH17) cells when induced Treg (iTreg) cells are compromised3,4. How Helicobacter and other gut bacteria direct T cells to adopt distinct functions remains poorly understood. Here we investigated the cells and molecular components required for iTreg cell differentiation. We found that antigen presentation by cells expressing RORγt, rather than by classical dendritic cells, was required and sufficient for induction of Treg cells. These RORγt+ cells-probably type 3 innate lymphoid cells and/or Janus cells5-require the antigen-presentation machinery, the chemokine receptor CCR7 and the TGFβ activator αv integrin. In the absence of any of these factors, there was expansion of pathogenic TH17 cells instead of iTreg cells, induced by CCR7-independent antigen-presenting cells. Thus, intestinal commensal microbes and their products target multiple antigen-presenting cells with pre-determined features suited to directing appropriate T cell differentiation programmes, rather than a common antigen-presenting cell that they endow with appropriate functions.
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Affiliation(s)
- Ranit Kedmi
- Molecular Pathogenesis Program, The Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, NY, USA
| | - Tariq A Najar
- Molecular Pathogenesis Program, The Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, NY, USA
| | - Kailin R Mesa
- Molecular Pathogenesis Program, The Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, NY, USA
| | - Allyssa Grayson
- Molecular Pathogenesis Program, The Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, NY, USA.,Howard Hughes Medical Institute, New York, NY, USA
| | - Lina Kroehling
- Molecular Pathogenesis Program, The Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, NY, USA
| | - Yuhan Hao
- Center for Genomics and Systems Biology, New York University, New York, NY, USA.,New York Genome Center, New York, NY, USA
| | - Stephanie Hao
- Technology Innovation Lab, New York Genome Center, New York, NY, USA
| | - Maria Pokrovskii
- Molecular Pathogenesis Program, The Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, NY, USA.,Calico Life Sciences, LLC, South San Francisco, CA, USA
| | - Mo Xu
- Molecular Pathogenesis Program, The Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, NY, USA.,National Institute for Biological Sciences, Beijing, China
| | - Jhimmy Talbot
- Molecular Pathogenesis Program, The Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, NY, USA.,Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Jiaxi Wang
- Diabetes Center, University of California, San Francisco, San Francisco, CA, USA
| | - Joe Germino
- Diabetes Center, University of California, San Francisco, San Francisco, CA, USA
| | - Caleb A Lareau
- Department of Pathology, Stanford University, Stanford, CA, USA.,Parker Institute for Cancer Immunotherapy, Stanford University, Stanford, CA, USA.,Gladstone-UCSF Institute of Genomic Immunology, San Francisco, CA, USA
| | - Ansuman T Satpathy
- Department of Pathology, Stanford University, Stanford, CA, USA.,Parker Institute for Cancer Immunotherapy, Stanford University, Stanford, CA, USA.,Gladstone-UCSF Institute of Genomic Immunology, San Francisco, CA, USA
| | - Mark S Anderson
- Diabetes Center, University of California, San Francisco, San Francisco, CA, USA
| | - Terri M Laufer
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Department of Medicine, C. Michael Crescenz Veterans Administration Medical Center, Philadelphia, PA, USA
| | - Iannis Aifantis
- Department of Pathology, New York University School of Medicine, New York, NY, USA
| | - Juliet M Bartleson
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA.,Federation Bio, South San Francisco, CA, USA
| | - Paul M Allen
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Helena Paidassi
- CIRI, Centre International de Recherche en Infectiologie, Université de Lyon, INSERM U1111, Université Claude Bernard Lyon 1, CNRS UMR5308, ENS de Lyon, Lyon, France
| | - James M Gardner
- Diabetes Center, University of California, San Francisco, San Francisco, CA, USA.,Department of Surgery, University of California, San Francisco, San Francisco, CA, USA
| | - Marlon Stoeckius
- Technology Innovation Lab, New York Genome Center, New York, NY, USA.,10X Genomics, Stockholm, Sweden
| | - Dan R Littman
- Molecular Pathogenesis Program, The Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, NY, USA. .,Howard Hughes Medical Institute, New York, NY, USA.
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4
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Cockburn K, Annusver K, Gonzalez DG, Ganesan S, May DP, Mesa KR, Kawaguchi K, Kasper M, Greco V. Gradual differentiation uncoupled from cell cycle exit generates heterogeneity in the epidermal stem cell layer. Nat Cell Biol 2022; 24:1692-1700. [PMID: 36357619 PMCID: PMC9729105 DOI: 10.1038/s41556-022-01021-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 09/23/2022] [Indexed: 11/12/2022]
Abstract
Highly regenerative tissues continuously produce terminally differentiated cells to replace those that are lost. How they orchestrate the complex transition from undifferentiated stem cells towards post-mitotic, molecularly distinct and often spatially segregated differentiated populations is not well understood. In the adult skin epidermis, the stem cell compartment contains molecularly heterogeneous subpopulations1-4 whose relationship to the complete trajectory of differentiation remains unknown. Here we show that differentiation, from commitment to exit from the stem cell layer, is a multi-day process wherein cells transit through a continuum of transcriptional changes with upregulation of differentiation genes preceding downregulation of typical stemness genes. Differentiation-committed cells remain capable of dividing to produce daughter cells fated to further differentiate, demonstrating that differentiation is uncoupled from cell cycle exit. These cell divisions are not required as part of an obligate transit-amplifying programme but help to buffer the differentiating cell pool during heightened demand. Thus, instead of distinct contributions from multiple progenitors, a continuous gradual differentiation process fuels homeostatic epidermal turnover.
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Affiliation(s)
- Katie Cockburn
- grid.47100.320000000419368710Department of Genetics, Yale School of Medicine, New Haven, CT USA ,grid.14709.3b0000 0004 1936 8649Present Address: Department of Biochemistry and Rosalind & Morris Goodman Cancer Institute, McGill University, Montreal, Quebec Canada
| | - Karl Annusver
- grid.4714.60000 0004 1937 0626Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - David G. Gonzalez
- grid.47100.320000000419368710Department of Genetics, Yale School of Medicine, New Haven, CT USA
| | - Smirthy Ganesan
- grid.47100.320000000419368710Department of Genetics, Yale School of Medicine, New Haven, CT USA
| | - Dennis P. May
- grid.47100.320000000419368710Department of Genetics, Yale School of Medicine, New Haven, CT USA
| | - Kailin R. Mesa
- grid.47100.320000000419368710Department of Genetics, Yale School of Medicine, New Haven, CT USA
| | - Kyogo Kawaguchi
- grid.508743.dNonequilibrium Physics of Living Matter RIKEN Habuki Research Team, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan ,grid.7597.c0000000094465255RIKEN Cluster for Pioneering Research, Kobe, Japan ,grid.26999.3d0000 0001 2151 536XUniversal Biology Institute, The University of Tokyo, Tokyo, Japan
| | - Maria Kasper
- grid.4714.60000 0004 1937 0626Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Valentina Greco
- grid.47100.320000000419368710Department of Genetics, Yale School of Medicine, New Haven, CT USA ,grid.47100.320000000419368710Departments of Cell Biology and Dermatology, Yale Stem Cell Center, Yale Cancer Center, Yale School of Medicine, New Haven, CT USA
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5
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Xu H, Wu L, Nguyen HH, Mesa KR, Raghavan V, Episkopou V, Littman DR. Arkadia-SKI/SnoN signaling differentially regulates TGF-β-induced iTreg and Th17 cell differentiation. J Exp Med 2021; 218:212614. [PMID: 34473197 PMCID: PMC8421263 DOI: 10.1084/jem.20210777] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 06/29/2021] [Accepted: 08/19/2021] [Indexed: 12/22/2022] Open
Abstract
TGF-β signaling is fundamental for both Th17 and regulatory T (Treg) cell differentiation. However, these cells differ in requirements for downstream signaling components, such as SMAD effectors. To further characterize mechanisms that distinguish TGF-β signaling requirements for Th17 and Treg cell differentiation, we investigated the role of Arkadia (RNF111), an E3 ubiquitin ligase that mediates TGF-β signaling during development. Inactivation of Arkadia in CD4+ T cells resulted in impaired Treg cell differentiation in vitro and loss of RORγt+FOXP3+ iTreg cells in the intestinal lamina propria, which increased susceptibility to microbiota-induced mucosal inflammation. In contrast, Arkadia was dispensable for Th17 cell responses. Furthermore, genetic ablation of two Arkadia substrates, the transcriptional corepressors SKI and SnoN, rescued Arkadia-deficient iTreg cell differentiation both in vitro and in vivo. These results reveal distinct TGF-β signaling modules governing Th17 and iTreg cell differentiation programs that could be targeted to selectively modulate T cell functions.
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Affiliation(s)
- Hao Xu
- The Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, NY
| | - Lin Wu
- The Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, NY
| | - Henry H Nguyen
- The Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, NY
| | - Kailin R Mesa
- The Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, NY
| | - Varsha Raghavan
- The Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, NY
| | | | - Dan R Littman
- The Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, NY.,Howard Hughes Medical Institute, New York, NY
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6
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Mesa KR, Kawaguchi K, Cockburn K, Gonzalez D, Boucher J, Xin T, Klein AM, Greco V. Homeostatic Epidermal Stem Cell Self-Renewal Is Driven by Local Differentiation. Cell Stem Cell 2018; 23:677-686.e4. [PMID: 30269903 DOI: 10.1016/j.stem.2018.09.005] [Citation(s) in RCA: 111] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 08/02/2018] [Accepted: 09/06/2018] [Indexed: 11/28/2022]
Abstract
Maintenance of adult tissues depends on sustained activity of resident stem cell populations, but the mechanisms that regulate stem cell self-renewal during homeostasis remain largely unknown. Using an imaging and tracking approach that captures all epidermal stem cell activity in large regions of living mice, we show that self-renewal is locally coordinated with epidermal differentiation, with a lag time of 1 to 2 days. In both homeostasis and upon experimental perturbation, we find that differentiation of a single stem cell is followed by division of a direct neighbor, but not vice versa. Finally, we show that exit from the stem cell compartment is sufficient to drive neighboring stem cell self-renewal. Together, these findings establish that epidermal stem cell self-renewal is not the constitutive driver of homeostasis. Instead, it is precisely tuned to tissue demand and responds directly to neighbor cell differentiation.
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Affiliation(s)
- Kailin R Mesa
- Department of Genetics, Yale School of Medicine, New Haven, CT 06510, USA
| | - Kyogo Kawaguchi
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA; Universal Biology Institute, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Katie Cockburn
- Department of Genetics, Yale School of Medicine, New Haven, CT 06510, USA.
| | - David Gonzalez
- Department of Genetics, Yale School of Medicine, New Haven, CT 06510, USA
| | - Jonathan Boucher
- Department of Genetics, Yale School of Medicine, New Haven, CT 06510, USA
| | - Tianchi Xin
- Department of Genetics, Yale School of Medicine, New Haven, CT 06510, USA
| | - Allon M Klein
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA.
| | - Valentina Greco
- Department of Genetics, Yale School of Medicine, New Haven, CT 06510, USA; Departments of Cell Biology and Dermatology, Yale Stem Cell Center, Yale Cancer Center, Yale School of Medicine, New Haven, CT 06510, USA.
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7
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Park S, Gonzalez DG, Guirao B, Boucher JD, Cockburn K, Marsh ED, Mesa KR, Brown S, Rompolas P, Haberman AM, Bellaïche Y, Greco V. Tissue-scale coordination of cellular behaviour promotes epidermal wound repair in live mice. Nat Cell Biol 2017; 19:155-163. [PMID: 28248302 PMCID: PMC5581297 DOI: 10.1038/ncb3472] [Citation(s) in RCA: 137] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 01/12/2017] [Indexed: 12/17/2022]
Abstract
Tissue repair is fundamental to our survival as tissues are challenged by recurrent damage. During mammalian skin repair, cells respond by migrating and proliferating to close the wound. However, the coordination of cellular repair behaviours and their effects on homeostatic functions in a live mammal remains unclear. Here we capture the spatiotemporal dynamics of individual epithelial behaviours by imaging wound re-epithelialization in live mice. Differentiated cells migrate while the rate of differentiation changes depending on local rate of migration and tissue architecture. Cells depart from a highly proliferative zone by directionally dividing towards the wound while collectively migrating. This regional coexistence of proliferation and migration leads to local expansion and elongation of the repairing epithelium. Finally, proliferation functions to pattern and restrict the recruitment of undamaged cells. This study elucidates the interplay of cellular repair behaviours and consequent changes in homeostatic behaviours that support tissue-scale organization of wound re-epithelialization.
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Affiliation(s)
- Sangbum Park
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut 06510, USA
| | - David G. Gonzalez
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut 06510, USA
- Department of Laboratory Medicine, Department of Immunobiology, Yale School of Medicine, New Haven, Connecticut 06510, USA
| | - Boris Guirao
- Polarity, Division and Morphogenesis Team, Genetics and Developmental Biology Unit (CNRS UMR3215/Inserm U934), Institut Curie, Paris, France
| | - Jonathan D. Boucher
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut 06510, USA
| | - Katie Cockburn
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut 06510, USA
| | - Edward D. Marsh
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut 06510, USA
| | - Kailin R. Mesa
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut 06510, USA
| | - Samara Brown
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut 06510, USA
| | - Panteleimon Rompolas
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut 06510, USA
| | - Ann M. Haberman
- Department of Laboratory Medicine, Department of Immunobiology, Yale School of Medicine, New Haven, Connecticut 06510, USA
| | - Yohanns Bellaïche
- Polarity, Division and Morphogenesis Team, Genetics and Developmental Biology Unit (CNRS UMR3215/Inserm U934), Institut Curie, Paris, France
| | - Valentina Greco
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut 06510, USA
- Departments of Cell Biology and Dermatology, Yale Stem Cell Center, Yale Cancer Center, Yale School of Medicine, New Haven, Connecticut 06510, USA
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8
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Rompolas P, Mesa KR, Kawaguchi K, Park S, Gonzalez D, Brown S, Boucher J, Klein AM, Greco V. Spatiotemporal coordination of stem cell commitment during epidermal homeostasis. Science 2016; 352:1471-4. [PMID: 27229141 DOI: 10.1126/science.aaf7012] [Citation(s) in RCA: 149] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 05/18/2016] [Indexed: 12/30/2022]
Abstract
Adult tissues replace lost cells via pools of stem cells. However, the mechanisms of cell self-renewal, commitment, and functional integration into the tissue remain unsolved. Using imaging techniques in live mice, we captured the lifetime of individual cells in the ear and paw epidermis. Our data suggest that epidermal stem cells have equal potential to either divide or directly differentiate. Tracking stem cells over multiple generations reveals that cell behavior is not coordinated between generations. However, sibling cell fate and lifetimes are coupled. We did not observe regulated asymmetric cell divisions. Lastly, we demonstrated that differentiating stem cells integrate into preexisting ordered spatial units of the epidermis. This study elucidates how a tissue is maintained by both temporal and spatial coordination of stem cell behaviors.
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Affiliation(s)
| | - Kailin R Mesa
- Department of Genetics, Yale School of Medicine, New Haven, CT 06510, USA
| | - Kyogo Kawaguchi
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Sangbum Park
- Department of Genetics, Yale School of Medicine, New Haven, CT 06510, USA
| | - David Gonzalez
- Department of Genetics, Yale School of Medicine, New Haven, CT 06510, USA
| | - Samara Brown
- Department of Genetics, Yale School of Medicine, New Haven, CT 06510, USA
| | - Jonathan Boucher
- Department of Genetics, Yale School of Medicine, New Haven, CT 06510, USA
| | - Allon M Klein
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Valentina Greco
- Department of Genetics, Yale School of Medicine, New Haven, CT 06510, USA. Departments of Dermatology and Cell Biology, Yale Stem Cell Center, Yale Cancer Center, Yale School of Medicine, New Haven, CT 06510, USA
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9
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Abstract
Most tissues in our bodies undergo constant cellular turnover. This process requires a dynamic balance between cell production and elimination. Stem cells have been shown in many of these tissues to be the major source of new cells. However, despite the tremendous advances made, it still remains unclear how stem cell behavior and activity are regulated in vivo. Furthermore, we lack basic understanding for the mechanisms that coordinate niche/stem cell interactions to maintain normal tissue homeostasis. Our lab has established a novel imaging approach in live mice using the skin as a model system to investigate these fundamental processes in both physiological and pathological settings such as cancer, with the goal of understanding how tissues successfully orchestrate tissue regeneration throughout the lifetime of an organism.
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Affiliation(s)
- Kailin R Mesa
- Department of Genetics, Yale School of Medicine, New Haven, CT 06510, USA
| | | | - Valentina Greco
- Department of Genetics, Yale School of Medicine, New Haven, CT 06510, USA; Department of Dermatology, Yale School of Medicine, New Haven, CT 06510, USA; Yale Stem Cell Center, Yale School of Medicine, New Haven, CT 06510, USA; Yale Cancer Center, Yale School of Medicine, New Haven, CT 06510, USA.
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10
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Mesa KR, Greco V. Linking morphogen and chromatin in the hair follicle. Dev Cell 2013; 25:113-4. [PMID: 23639438 DOI: 10.1016/j.devcel.2013.04.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In this issue of Developmental Cell, Xiong et al. (2013) identify a critical role for the chromatin remodeler Brg1 in hair follicle stem cell maintenance and epidermal repair. Brg1 interacts with the Shh signaling pathway to create a positive feedback loop that fuels hair follicle growth.
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Affiliation(s)
- Kailin R Mesa
- Department of Genetics, Yale Stem Cell Center, Yale School of Medicine, New Haven, CT 06510, USA
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11
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Wilhelmsen K, Mesa KR, Lucero J, Xu F, Hellman J. ERK5 protein promotes, whereas MEK1 protein differentially regulates, the Toll-like receptor 2 protein-dependent activation of human endothelial cells and monocytes. J Biol Chem 2012; 287:26478-94. [PMID: 22707717 DOI: 10.1074/jbc.m112.359489] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Endothelial cell (EC) Toll-like receptor 2 (TLR2) activation up-regulates the expression of inflammatory mediators and of TLR2 itself and modulates important endothelial functions, including coagulation and permeability. We defined TLR2 signaling pathways in EC and tested the hypothesis that TLR2 signaling differs in EC and monocytes. We found that ERK5, heretofore unrecognized as mediating TLR2 activation in any cell type, is a central mediator of TLR2-dependent inflammatory signaling in human umbilical vein endothelial cells, primary human lung microvascular EC, and human monocytes. Additionally, we observed that, although MEK1 negatively regulates TLR2 signaling in EC, MEK1 promotes TLR2 signaling in monocytes. We also noted that activation of TLR2 led to the up-regulation of intracellularly expressed TLR2 and inflammatory mediators via NF-κB, JNK, and p38-MAPK. Finally, we found that p38-MAPK, JNK, ERK5, and NF-κB promote the attachment of human neutrophils to lung microvascular EC that were pretreated with TLR2 agonists. This study newly identifies ERK5 as a key regulator of TLR2 signaling in EC and monocytes and indicates that there are fundamental differences in TLR signaling pathways between EC and monocytes.
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Affiliation(s)
- Kevin Wilhelmsen
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, California 94143,USA.
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Wilhelmsen K, Mesa KR, Prakash A, Xu F, Hellman J. Activation of endothelial TLR2 by bacterial lipoprotein upregulates proteins specific for the neutrophil response. Innate Immun 2011; 18:602-16. [PMID: 22186927 DOI: 10.1177/1753425911429336] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The vascular endothelium is integrally involved in the host response to infection and in organ failure during acute inflammatory disorders such as sepsis. Gram-negative and Gram-positive bacterial lipoproteins circulate in sepsis and can directly activate the endothelium by binding to endothelial cell (EC) TLR2. In this report, we perform the most comprehensive analysis to date of the immune-related genes regulated after activation of endothelial TLR2 by bacterial di- and triacylated lipopeptides. We found that TLR2 activation specifically induces the expression of the genes IL-6, IL-8, CSF2, CSF3, ICAM1 and SELE by human umbilical vein ECs and human lung microvascular ECs. These proteins participate in neutrophil recruitment, adherence and activation at sites of inflammation. Significantly, our studies demonstrate that TLR2-mediated EC responses are specifically geared towards recruitment, activation, and survival of neutrophils and not mononuclear leukocytes, that ECs do not require priming by other inflammatory stimuli to respond to bacterial lipopeptides and, unlike mononuclear leukocytes, TLR2 agonists do not induce ECs to secrete TNF-α. This study suggests that endothelial TLR2 may be an important regulator of neutrophil trafficking to sites of infection in general, and that direct activation of lung endothelial TLR2 may contribute to acute lung injury during sepsis.
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Affiliation(s)
- Kevin Wilhelmsen
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, CA 94143, USA
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