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Sei Y, Feng J, Zhao X, Wank SA. Role of an active reserve stem cell subset of enteroendocrine cells in intestinal stem cell dynamics and the genesis of small intestinal neuroendocrine tumors. Am J Physiol Gastrointest Liver Physiol 2020; 319:G494-G501. [PMID: 32845170 PMCID: PMC7654644 DOI: 10.1152/ajpgi.00278.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Small intestinal neuroendocrine tumors (SI-NET) are serotonin-secreting well-differentiated neuroendocrine tumors of putative enterochromaffin (EC) cell origin. Recent studies recognize a subset of EC cells that is label-retaining at the +4 position in the crypt and functions as a reserve intestinal stem cell. Importantly, this +4 reserve EC cell subset not only contributes to regeneration of the intestinal epithelium during injury and inflammation but also to basal crypt homeostasis at a constant rate. The latter function suggests that the +4 EC cell subset serves as an active reserve stem cell via a constant rate of dedifferentiation. Characterization of early tumor formation of SI-NET, observed as crypt-based EC cell clusters in many cases of familial SI-NETs, suggests that the +4 active reserve EC cell subset is the cell of origin. This newly discovered active reserve stem cell property of EC cells can account for unique biological mechanisms and processes associated with the genesis and development of SI-NETs. The recognition of this property of the +4 active reserve EC cell subset may provide novel opportunities to explore NETs in the gastrointestinal tract and other organs.
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Affiliation(s)
- Yoshitatsu Sei
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Jianying Feng
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Xilin Zhao
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Stephen A. Wank
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
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Sei Y, Feng J, Samsel L, White A, Zhao X, Yun S, Citrin D, McCoy JP, Sundaresan S, Hayes MM, Merchant JL, Leiter A, Wank SA. Mature enteroendocrine cells contribute to basal and pathological stem cell dynamics in the small intestine. Am J Physiol Gastrointest Liver Physiol 2018; 315:G495-G510. [PMID: 29848020 PMCID: PMC6230697 DOI: 10.1152/ajpgi.00036.2018] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Lgr5-expressing intestinal stem cells (ISCs) maintain continuous and rapid generation of the intestinal epithelium. Here, we present evidence that dedifferentiation of committed enteroendocrine cells (EECs) contributes to maintenance of the epithelium under both basal conditions and in response to injury. Lineage-tracing studies identified a subset of EECs that reside at +4 position for more than 2 wk, most of which were BrdU-label-retaining cells. Under basal conditions, cells derived from these EECs grow from the bottom of the crypt to generate intestinal epithelium according to neutral drift kinetics that is consistent with dedifferentiation of mature EECs to ISCs. The lineage tracing of EECs demonstrated reserve stem cell properties in response to radiation-induced injury with the generation of reparative EEC-derived epithelial patches. Finally, the enterochromaffin (EC) cell was the predominant EEC type participating in these stem cell dynamics. These results provide novel insights into the +4 reserve ISC hypothesis, stem cell dynamics of the intestinal epithelium, and in the development of EC-derived small intestinal tumors. NEW & NOTEWORTHY The current manuscript demonstrating that a subset of mature enteroendocrine cells (EECs), predominantly enterochromaffin cells, dedifferentiates to fully functional intestinal stem cells (ISCs) is novel, timely, and important. These cells dedifferentiate to ISCs not only in response to injury but also under basal homeostatic conditions. These novel findings provide a mechanism in which a specified cell can dedifferentiate and contribute to normal tissue plasticity as well as the development of EEC-derived intestinal tumors under pathologic conditions.
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Affiliation(s)
- Yoshitatsu Sei
- 1Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Jianying Feng
- 1Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Leigh Samsel
- 2Flow Cytometry Core Facility, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Ayla White
- 3Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Xilin Zhao
- 1Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Sajung Yun
- 1Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Deborah Citrin
- 3Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - J. Philip McCoy
- 2Flow Cytometry Core Facility, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Sinju Sundaresan
- 4Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, Michigan
| | - Michael M. Hayes
- 4Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, Michigan
| | - Juanita L. Merchant
- 5Department of Molecular and Integrative Physiology, University of Michigan Medical Center, Ann Arbor, Michigan
| | - Andrew Leiter
- 6Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Stephen A. Wank
- 1Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
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