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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] [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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Bertassoni LE. Bioprinting of Complex Multicellular Organs with Advanced Functionality-Recent Progress and Challenges Ahead. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2101321. [PMID: 35060652 PMCID: PMC10171718 DOI: 10.1002/adma.202101321] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 04/20/2021] [Indexed: 05/12/2023]
Abstract
Bioprinting has emerged as one of the most promising strategies for fabrication of functional organs in the lab as an alternative to transplant organs. While progress in the field has mostly been restricted to a few miniaturized tissues with minimal biological functionality until a few years ago, recent progress has advanced the concept of building three-dimensional multicellular organ complexity remarkably. This review discusses a series of milestones that have paved the way for bioprinting of tissue constructs that have advanced levels of biological and architectural functionality. Critical materials, engineering and biological challenges that are key to addressing the desirable function of engineered organs are presented. These are discussed in light of the many difficulties to replicate the heterotypic organization of multicellular solid organs, the nanoscale precision of the extracellular microenvironment in hierarchical tissues, as well as the advantages and limitations of existing bioprinting methods to adequately overcome these barriers. In summary, the advances of the field toward realistic manufacturing of functional organs have never been so extensive, and this manuscript serves as a road map for some of the recent progress and the challenges ahead.
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Affiliation(s)
- Luiz E Bertassoni
- Division of Biomaterials and Biomechanics, School of Dentistry, Oregon Health and Science University, Portland, OR, 97201, USA
- Department of Biomedical Engineering, School of Medicine, Oregon Health and Science University, Portland, OR, 97239, USA
- Center for Regenerative Medicine, Oregon Health and Science University, Portland, OR, 97239, USA
- Cancer Early Detection Advanced Research (CEDAR), Knight Cancer Institute, Oregon Health and Science University, Portland, OR, 97239, USA
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3
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Automated Segmentation of Fluorescence Microscopy Images for 3D Cell Detection in human-derived Cardiospheres. Sci Rep 2019; 9:6644. [PMID: 31040327 PMCID: PMC6491482 DOI: 10.1038/s41598-019-43137-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 04/09/2019] [Indexed: 12/16/2022] Open
Abstract
The ‘cardiosphere’ is a 3D cluster of cardiac progenitor cells recapitulating a stem cell niche-like microenvironment with a potential for disease and regeneration modelling of the failing human myocardium. In this multicellular 3D context, it is extremely important to decrypt the spatial distribution of cell markers for dissecting the evolution of cellular phenotypes by direct quantification of fluorescent signals in confocal microscopy. In this study, we present a fully automated method, named CARE (‘CARdiosphere Evaluation’), for the segmentation of membranes and cell nuclei in human-derived cardiospheres. The proposed method is tested on twenty 3D-stacks of cardiospheres, for a total of 1160 images. Automatic results are compared with manual annotations and two open-source software designed for fluorescence microscopy. CARE performance was excellent in cardiospheres membrane segmentation and, in cell nuclei detection, the algorithm achieved the same performance as two expert operators. To the best of our knowledge, CARE is the first fully automated algorithm for segmentation inside in vitro 3D cell spheroids, including cardiospheres. The proposed approach will provide, in the future, automated quantitative analysis of markers distribution within the cardiac niche-like environment, enabling predictive associations between cell mechanical stresses and dynamic phenotypic changes.
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Khatami M. Cancer; an induced disease of twentieth century! Induction of tolerance, increased entropy and 'Dark Energy': loss of biorhythms (Anabolism v. Catabolism). Clin Transl Med 2018; 7:20. [PMID: 29961900 PMCID: PMC6026585 DOI: 10.1186/s40169-018-0193-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2018] [Accepted: 05/29/2018] [Indexed: 12/15/2022] Open
Abstract
Maintenance of health involves a synchronized network of catabolic and anabolic signals among organs/tissues/cells that requires differential bioenergetics from mitochondria and glycolysis (biological laws or biorhythms). We defined biological circadian rhythms as Yin (tumoricidal) and Yang (tumorigenic) arms of acute inflammation (effective immunity) involving immune and non-immune systems. Role of pathogens in altering immunity and inducing diseases and cancer has been documented for over a century. However, in 1955s decision makers in cancer/medical establishment allowed public (current baby boomers) to consume million doses of virus-contaminated polio vaccines. The risk of cancer incidence and mortality sharply rose from 5% (rate of hereditary/genetic or innate disease) in 1900s, to its current scary status of 33% or 50% among women and men, respectively. Despite better hygiene, modern detection technologies and discovery of antibiotics, baby boomers and subsequent 2–3 generations are sicker than previous generations at same age. American health status ranks last among other developed nations while America invests highest amount of resources for healthcare. In this perspective we present evidence that cancer is an induced disease of twentieth century, facilitated by a great deception of cancer/medical establishment for huge corporate profits. Unlike popularized opinions that cancer is 100, 200 or 1000 diseases, we demonstrate that cancer is only one disease; the severe disturbances in biorhythms (differential bioenergetics) or loss of balance in Yin and Yang of effective immunity. Cancer projects that are promoted and funded by decision makers are reductionist approaches, wrong and unethical and resulted in loss of millions of precious lives and financial toxicity to society. Public vaccination with pathogen-specific vaccines (e.g., flu, hepatitis, HPV, meningitis, measles) weakens, not promotes, immunity. Results of irresponsible projects on cancer sciences or vaccines are increased population of drug-dependent sick society. Outcome failure rates of claimed ‘targeted’ drugs, ‘precision’ or ‘personalized’ medicine are 90% (± 5) for solid tumors. We demonstrate that aging, frequent exposures to environmental hazards, infections and pathogen-specific vaccines and ingredients are ‘antigen overload’ for immune system, skewing the Yin and Yang response profiles and leading to induction of ‘mild’, ‘moderate’ or ‘severe’ immune disorders. Induction of decoy or pattern recognition receptors (e.g., PRRs), such as IRAK-M or IL-1dRs (‘designer’ molecules) and associated genomic instability and over-expression of growth promoting factors (e.g., pyruvate kinases, mTOR and PI3Ks, histamine, PGE2, VEGF) could lead to immune tolerance, facilitating cancer cells to hijack anabolic machinery of immunity (Yang) for their increased growth requirements. Expression of constituent embryonic factors would negatively regulate differentiation of tumor cells through epithelial–mesenchymal-transition and create “dual negative feedback loop” that influence tissue metabolism under hypoxic conditions. It is further hypothesized that induction of tolerance creates ‘dark energy’ and increased entropy and temperature in cancer microenvironment allowing disorderly cancer proliferation and mitosis along with increased glucose metabolism via Crabtree and Pasteur Effects, under mitophagy and ribophagy, conditions that are toxic to host survival. Effective translational medicine into treatment requires systematic and logical studies of complex interactions of tumor cells with host environment that dictate clinical outcomes. Promoting effective immunity (biological circadian rhythms) are fundamental steps in correcting host differential bioenergetics and controlling cancer growth, preventing or delaying onset of diseases and maintaining public health. The author urges independent professionals and policy makers to take a closer look at cancer dilemma and stop the ‘scientific/medical ponzi schemes’ of a powerful group that control a drug-dependent sick society before all hopes for promoting public health evaporate.
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Affiliation(s)
- Mahin Khatami
- Inflammation, Aging and Cancer, National Cancer Institute (NCI), National Institutes of Health (NIH), Bethesda, MD, USA.
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Hu JY, Yu D, Wu YH. Primary non-Hodgkin lymphoma of the right femur and subsequent metastasis to the left femur: A case report and literature review. Oncol Lett 2018. [PMID: 29541210 DOI: 10.3892/ol.2018.7895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Non-Hodgkin lymphoma of the bone is rare and typically causes an extensive bone lesion. The present study describes a case of diffuse large B-cell primary non-Hodgkin lymphoma of the bone, which occurred in the right femur, and was initially treated with surgery and chemotherapy. Following a 7-year period of complete remission, a new, similar lesion was identified in the left femur. With both lesions, there was no accompanying destruction of any other bones or organ involvement. Metastasis of PLB to the contralateral side is extremely rare and, to the best of our knowledge, this is the first report of this particular presentation in China or worldwide. We hypothesized that the present situation arose due to mechanisms involving the tumor microenvironment, circulating tumor cells, lymphocyte homing and self-seeding. The present report describes the case in detail, and discusses the possible underlying mechanisms and their potential contribution to the treatment of non-Hodgkin lymphoma, as well as the prevention of metastasis and recurrence, which may be of considerable clinical significance.
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Affiliation(s)
- Jing-Yu Hu
- Department of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China
| | - Dan Yu
- Department of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China.,Department of Hematology, Wuhan First Hospital, Wuhan, Hubei 430030, P.R. China
| | - Yao-Hui Wu
- Department of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China
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Pesce M, Messina E, Chimenti I, Beltrami AP. Cardiac Mechanoperception: A Life-Long Story from Early Beats to Aging and Failure. Stem Cells Dev 2016; 26:77-90. [PMID: 27736363 DOI: 10.1089/scd.2016.0206] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The life-long story of the heart starts concomitantly with primary differentiation events occurring in multipotent progenitors located in the so-called heart tube. This initially tubular structure starts a looping process, which leads to formation of the final four-chambered heart with a primary contribution of geometric and position-associated cell sensing. While this establishes the correct patterning of the final cardiac structure, it also provides feedbacks to fundamental cellular machineries controlling proliferation and differentiation, thus ensuring a coordinated restriction of cell growth and a myocyte terminal differentiation. Novel evidences provided by embryological and cell engineering studies have clarified the relevance of mechanics-supported position sensing for the correct recognition of cell fate inside developing embryos and multicellular aggregates. One of the main components of this pathway, the Hippo-dependent signal transduction machinery, is responsible for cell mechanics intracellular transduction with important consequences for gene transcription and cell growth control. Being the Hippo pathway also directly connected to stress responses and altered metabolism, it is tempting to speculate that permanent alterations of mechanosensing may account for modifying self-renewal control in tissue homeostasis. In the present contribution, we translate these concepts to the aging process and the failing of the human heart, two pathophysiologic conditions that are strongly affected by stress responses and altered metabolism.
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Affiliation(s)
- Maurizio Pesce
- 1 Tissue Engineering Research Unit, Centro Cardiologico Monzino, IRCCS , Milan, Italy
| | - Elisa Messina
- 2 Department of Pediatric Cardiology, "Sapienza" University , Rome, Italy
| | - Isotta Chimenti
- 3 Department of Medical Surgical Science and Biotechnology, "Sapienza" University , Rome, Italy
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7
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Abstract
To maintain cycling adult tissue in homeostasis the balance between proliferation and differentiation of stem cells needs to be precisely regulated. To investigate how stem cells achieve perfect self-renewal, emphasis has been placed on models in which stem cells progress sequentially through a one-way proliferative hierarchy. However, investigations of tissue regeneration have revealed a surprising degree of flexibility, with cells normally committed to differentiation able to recover stem cell competence following injury. Here, we investigate whether the reversible transfer of cells between states poised for proliferation or differentiation may provide a viable mechanism for a heterogeneous stem cell population to maintain homeostasis even under normal physiological conditions. By addressing the clonal dynamics, we show that such models of "dynamic heterogeneity" may be equally capable of describing the results of recent lineage tracing assays involving epithelial tissues. Moreover, together with competition for limited niche access, such models may provide a mechanism to render tissue homeostasis robust. In particular, in 2D epithelial layers, we show that the mechanism of dynamic heterogeneity avoids some pathological dependencies that undermine models based on a hierarchical stem/progenitor organization.
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The Interplay between Wnt Mediated Expansion and Negative Regulation of Growth Promotes Robust Intestinal Crypt Structure and Homeostasis. PLoS Comput Biol 2015; 11:e1004285. [PMID: 26288152 PMCID: PMC4543550 DOI: 10.1371/journal.pcbi.1004285] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 03/31/2015] [Indexed: 12/22/2022] Open
Abstract
The epithelium of the small intestinal crypt, which has a vital role in protecting the underlying tissue from the harsh intestinal environment, is completely renewed every 4–5 days by a small pool of stem cells at the base of each crypt. How is this renewal controlled and homeostasis maintained, particularly given the rapid nature of this process? Here, based on the recent observations from in vitro “mini gut” studies, we use a hybrid stochastic model of the crypt to investigate how exogenous niche signaling (from Wnt and BMP) combines with auto-regulation to promote homeostasis. This model builds on the sub-cellular element method to account for the three-dimensional structure of the crypt, external regulation by Wnt and BMP, internal regulation by Notch signaling, as well as regulation by internally generated diffusible signals. Results show that Paneth cell derived Wnt signals, which have been observed experimentally to sustain crypts in cultured organs, have a dramatically different influence on niche dynamics than does mesenchyme derived Wnt. While this signaling can indeed act as a redundant backup to the exogenous gradient, it introduces a positive feedback that destabilizes the niche and causes its uncontrolled expansion. We find that in this setting, BMP has a critical role in constraining this expansion, consistent with observations that its removal leads to crypt fission. Further results also point to a new hypothesis for the role of Ephrin mediated motility of Paneth cells, specifically that it is required to constrain niche expansion and maintain the crypt’s spatial structure. Combined, these provide an alternative view of crypt homeostasis where the niche is in a constant state of expansion and the spatial structure of the crypt arises as a balance between this expansion and the action of various sources of negative regulation that hold it in check. The small intestinal epithelium, like our skin, is constantly being renewed. In the intestine however, this epithelium is exposed to the harsh digestive environment, necessitating much more rapid renewal. Remarkably, the entire epithelium is renewed every 4–5 days. This raises the question, how can the size and structure of this tissue be maintained given this pace. Motivated by recent experimental observations, we construct a three-dimensional, hybrid stochastic model to investigate the mechanisms responsible for homeostasis of this tissue. We find that there are redundant signals created by both the epithelium itself and surrounding tissues that act in parallel to maintain epithelial structure. This redundancy comes at a price however: it introduces the possibility of explosive stem cell population growth. Additional results suggest that other signals along with choreographed motion of cells are responsible for repressing this expansion. Taken together, our results provide a novel hypothesis for how robust but fast renewal of the crypt is achieved: as a balance between expansion, which drives fast renewal and repression, which holds that expansion in check to maintain the crypt’s structure.
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9
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Abstract
ABSTRACT Cancers exhibit differences in metastatic behavior and drug sensitivity that correlate with certain tumor-specific variables such as differentiation grade, growth rate/extent and molecular regulatory aberrations. In practice, patient management is based on the past results of clinical trials adjusted for these biomarkers. Here, it is proposed that treatment strategies could be fine-tuned upfront simply by quantifying tumorigenic spatial (cell growth) and temporal (genetic stability) control losses, as predicted by genetic defects of cell-cycle-regulatory gatekeeper and genome-stabilizing caretaker tumor suppressor genes, respectively. These differential quantifications of tumor dysfunction may in turn be used to create a tumor-specific ‘periodic table’ that guides rational formulation of survival-enhancing anticancer treatment strategies.
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Affiliation(s)
- Richard J Epstein
- *Clinical Informatics & Research Centre, The Kinghorn Cancer Centre, 370 Victoria St, Darlinghurst 2010, Sydney, Australia
- Laboratory of Genome Evolution, Garvan Institute for Medical Research, 384 Victoria St, Darlinghurst 2010, Sydney, Australia
- Department of Oncology, & UNSW Clinical School, St Vincent's Hospital, 390 Victoria St, Darlinghurst 2010 Sydney, Australia
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10
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Santos Franco S, Raveh-Amit H, Kobolák J, Alqahtani MH, Mobasheri A, Dinnyes A. The crossroads between cancer stem cells and aging. BMC Cancer 2015; 15 Suppl 1:S1. [PMID: 25708542 PMCID: PMC4331724 DOI: 10.1186/1471-2407-15-s1-s1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The cancer stem cell (CSC) hypothesis suggests that only a subpopulation of cells within a tumour is responsible for the initiation and progression of neoplasia. The original and best evidence for the existence of CSCs came from advances in the field of haematological malignancies. Thus far, putative CSCs have been isolated from various solid and non-solid tumours and shown to possess self-renewal, differentiation, and cancer regeneration properties. Although research in the field is progressing extremely fast, proof of concept for the CSC hypothesis is still lacking and key questions remain unanswered, e.g. the cell of origin for these cells. Nevertheless, it is undisputed that neoplastic transformation is associated with genetic and epigenetic alterations of normal cells, and a better understanding of these complex processes is of utmost importance for developing new anti-cancer therapies. In the present review, we discuss the CSC hypothesis with special emphasis on age-associated alterations that govern carcinogenesis, at least in some types of tumours. We present evidence from the scientific literature for age-related genetic and epigenetic alterations leading to cancer and discuss the main challenges in the field.
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Holmes WR, Nie Q. Interactions and tradeoffs between cell recruitment, proliferation, and differentiation affect CNS regeneration. Biophys J 2014; 106:1528-36. [PMID: 24703314 DOI: 10.1016/j.bpj.2014.02.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Revised: 01/15/2014] [Accepted: 02/06/2014] [Indexed: 12/21/2022] Open
Abstract
Regeneration of central nervous system (CNS) lesions requires movement of progenitor cells and production of their differentiated progeny. Although damage to the CNS clearly promotes these two processes, the interplay between these complex events and how it affects a response remains elusive. Here, we use spatial stochastic modeling to show that tradeoffs arise between production and recruitment during regeneration. Proper spatial control of cell cycle timing can mitigate these tradeoffs, maximizing recruitment, improving infiltration into the lesion, and reducing wasteful production outside of it. Feedback regulation of cell lineage dynamics alone however leads to spatial defects in cell recruitment, suggesting a novel, to our knowledge, hypothesis for the aggregation of cells to the periphery of a lesion in multiple sclerosis. Interestingly, stronger chemotaxis does not correct this aggregation and instead, substantial random cell motions near the site of the lesion are required to improve CNS regeneration.
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Affiliation(s)
- William R Holmes
- Center for Mathematical and Computational Biology, Center for Complex Biological Systems, Department of Mathematics, University of California, Irvine, California
| | - Qing Nie
- Center for Mathematical and Computational Biology, Center for Complex Biological Systems, Department of Mathematics, University of California, Irvine, California.
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12
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Carulli AJ, Samuelson LC, Schnell S. Unraveling intestinal stem cell behavior with models of crypt dynamics. Integr Biol (Camb) 2014; 6:243-57. [PMID: 24480852 PMCID: PMC4007491 DOI: 10.1039/c3ib40163d] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The definition, regulation and function of intestinal stem cells (ISCs) has been hotly debated. Recent discoveries have started to clarify the nature of ISCs, but many questions remain. This review discusses the current advances and controversies of ISC biology as well as theoretical compartmental models that have been coupled with in vivo experimentation to investigate the mechanisms of ISC dynamics during homeostasis, tumorigenesis, repair and development. We conclude our review by discussing the key lingering questions in the field and proposing how many of these questions can be addressed using both compartmental models and experimental techniques.
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Affiliation(s)
- Alexis J. Carulli
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA.
| | - Linda C. Samuelson
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA.
- Department of Internal Medicine, Division of Gastroenterology, University of Michigan Medical School, Ann Arbor, Michigan, USA.
| | - Santiago Schnell
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA.
- Department for Computational Medicine & Bioinformatics, University of Michigan Medical School, Ann Arbor, Michigan, USA.
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13
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Kitada K, Nakano D, Hitomi H, Kobori H, Deguchi K, Mori H, Masaki T, Nishiyama A. Aldosterone induces p21-regulated apoptosis via increased synthesis and secretion of tumour necrosis factor-α in human proximal tubular cells. Clin Exp Pharmacol Physiol 2013; 39:858-63. [PMID: 23013131 DOI: 10.1111/1440-1681.12001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
1. Aldosterone has been shown to mediate p21-dependent cellular senescence in rat kidney proximal tubules in vivo and in cultured human proximal tubular cells. The p21-induced senescent cells express higher levels of apoptotic cytokines, such as tumour necrosis factor (TNF)-α compared with non-senescent cells. The aim of the present study was to investigate the hypothesis that aldosterone increases proximal tubular apoptosis by increasing the secretion of apoptosis-inducing factors through a p21-dependent mechanism. 2. Human proximal tubular cells were incubated with aldosterone (10 nmol/L) and cell senescence was detected by senescence-associated β-galactosidase staining and expression of p21. Apoptosis was analysed by terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end-labelling and annexin/propidium iodide staining, whereas p21 localization was determined by immunofluorescence. 3. Exposure of cells to aldosterone for 3 or 5 days increased senescence-associated β-galactosidase staining, p21 and TNF-α mRNA expression and secretion of TNF-α into the culture medium. These changes were abolished by gene silencing of p21. Aldosterone failed to increase the number of apoptotic cells on day 3, but did increase them on day 5. A neutralizing antibody against TNF-α prevented the aldosterone-induced apoptotic changes. Aldosterone did not affect localization of p21. 4. These findings indicate that aldosterone increases TNF-α synthesis and secretion in proximal tubular cells via p21/senescence-dependent cell phenotypic changes and that the TNF-α secreted plays an important role as a paracrine factor in mediating cell apoptosis, indicating a possible involvement in aldosterone-induced renal damage.
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Affiliation(s)
- Kento Kitada
- Department of Pharmacology, Kagawa University, Kagawa, Japan
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14
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Ovadia J, Nie Q. Stem cell niche structure as an inherent cause of undulating epithelial morphologies. Biophys J 2013; 104:237-46. [PMID: 23332076 PMCID: PMC3540249 DOI: 10.1016/j.bpj.2012.11.3807] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Revised: 11/21/2012] [Accepted: 11/27/2012] [Indexed: 01/07/2023] Open
Abstract
The spatial organization of stem cells into a niche is a key factor for growth and continual tissue renewal during development, sustenance, and regeneration. Stratified epithelia serve as a great context to study the spatial aspects of the stem cell niche and cell lineages by organizing into layers of different cell types. Several types of stratified epithelia develop morphologies with advantageous, protruding structures where stem cells reside, such as rete pegs and palisades of Vogt. Here, multistage, spatial cell lineage models for epithelial stratification are used to study how the stem cell niche influences epithelial morphologies. When the stem cell niche forms along a rigid basal lamina, relatively regular morphologies are maintained. In contrast, stem cell niche formation along a free-moving basal lamina may prompt distorted epithelial morphologies with stem cells accumulating at the tips of fingerlike structures that form. The correspondence between our simulated morphologies and developmental stages of the human epidermis is also explored. Overall, our work provides an understanding of how stratified epithelia may attain distorted morphologies and sheds light on the importance of the spatial aspects of the stem cell niche.
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Affiliation(s)
| | - Qing Nie
- Center for Mathematical and Computational Biology, Center for Complex Biological Systems, Department of Mathematics, University of California, Irvine, California
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