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Perry N, Braun R, Ben‐Hamo‐Arad A, Kanaan D, Arad T, Porat‐Kuperstein L, Toledano H. Integrin restriction by miR-34 protects germline progenitors from cell death during aging. Aging Cell 2024; 23:e14131. [PMID: 38450871 PMCID: PMC11166360 DOI: 10.1111/acel.14131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 02/07/2024] [Accepted: 02/11/2024] [Indexed: 03/08/2024] Open
Abstract
During aging, regenerative tissues must dynamically balance the two opposing processes of proliferation and cell death. While many microRNAs are differentially expressed during aging, their roles as dynamic regulators of tissue regeneration have yet to be described. We show that in the highly regenerative Drosophila testis, miR-34 levels are significantly elevated during aging. miR-34 modulates germ cell death and protects the progenitor germ cells from accelerated aging. However, miR-34 is not expressed in the progenitors themselves but rather in neighboring cyst cells that kill the progenitors. Transcriptomics followed by functional analysis revealed that during aging, miR-34 modifies integrin signaling by limiting the levels of the heterodimeric integrin receptor αPS2 and βPS subunits. In addition, we found that in cyst cells, this heterodimer is essential for inducing phagoptosis and degradation of the progenitor germ cells. Together, these data suggest that the miR-34-integrin signaling axis acts as a sensor of progenitor germ cell death to extend progenitor functionality during aging.
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Affiliation(s)
- Noam Perry
- Department of Human Biology, Faculty of Natural SciencesUniversity of HaifaHaifaIsrael
| | - Racheli Braun
- Department of Human Biology, Faculty of Natural SciencesUniversity of HaifaHaifaIsrael
- Biomedical Engineering FacultyTechnion IITsHaifaIsrael
| | - Aya Ben‐Hamo‐Arad
- Department of Human Biology, Faculty of Natural SciencesUniversity of HaifaHaifaIsrael
| | - Diana Kanaan
- Department of Human Biology, Faculty of Natural SciencesUniversity of HaifaHaifaIsrael
| | - Tal Arad
- Department of Human Biology, Faculty of Natural SciencesUniversity of HaifaHaifaIsrael
| | | | - Hila Toledano
- Department of Human Biology, Faculty of Natural SciencesUniversity of HaifaHaifaIsrael
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2
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Lv J, Yu H, Shan F, Ye J, Li A, Jing J, Zheng M, Tian D. Effect of Myelin Debris on the Phenotypic Transformation of Astrocytes after Spinal Cord Injury in Rats. Neuroscience 2024; 547:1-16. [PMID: 38570063 DOI: 10.1016/j.neuroscience.2024.03.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 03/19/2024] [Accepted: 03/23/2024] [Indexed: 04/05/2024]
Abstract
After spinal cord injury (SCI), the accumulation of myelin debris can serve as proinflammatory agents, hindering axon regrowth and exacerbating damage. While astrocytes have been implicated in the phagocytosis of myelin debris, the impact of this process on the phenotypic transformation of astrocytes and their characteristics following SCI in rats is not well understood. Here, we demonstrated that the conditioned medium of myelin debris can trigger apoptosis in rat primary astrocytes in vitro. Using a compressional SCI model in rats, we observed that astrocytes can engulf myelin debris through ATP-binding cassette transporter sub-family A member 1 (ABCA1), and these engulfed cells tend to transform into A1 astrocytes, as indicated by C3 expression. At 4 days post-injury (dpi), astrocytes rapidly transitioned into A1 astrocytes and maintained this phenotype from 4 to 28 dpi, while A2 astrocytes, characterized by S100, were only detected at 14 and 28 dpi. Reactive astrocytes, identified by Nestin, emerged at 4 and 7 dpi, whereas scar-forming astrocytes, marked by N-cadherin, were evident at 14 and 28 dpi. This study illustrates the distribution patterns of astrocyte subtypes and the potential interplay between astrocytes and myelin debris after SCI in rats. We emphasize that myelin debris can induce astrocyte apoptosis in vitro and promote the transformation of astrocytes into A1 astrocytes in vivo. These two classification methods are not mutually exclusive, but rather complementary.
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Affiliation(s)
- Jianwei Lv
- Department of Orthopaedics, The Second Affiliated Hospital of Anhui Medical University, Hefei 230601, China; Institute of Orthopaedics, Research Center for Translational Medicine, The Second Affiliated Hospital of Anhui Medical University, Hefei 230601, China
| | - Hang Yu
- Department of Orthopaedics, The Second Affiliated Hospital of Anhui Medical University, Hefei 230601, China; Institute of Orthopaedics, Research Center for Translational Medicine, The Second Affiliated Hospital of Anhui Medical University, Hefei 230601, China
| | - Fangli Shan
- Department of Orthopaedics, The Second Affiliated Hospital of Anhui Medical University, Hefei 230601, China; Institute of Orthopaedics, Research Center for Translational Medicine, The Second Affiliated Hospital of Anhui Medical University, Hefei 230601, China
| | - Jianan Ye
- Department of Orthopaedics, The Second Affiliated Hospital of Anhui Medical University, Hefei 230601, China; Institute of Orthopaedics, Research Center for Translational Medicine, The Second Affiliated Hospital of Anhui Medical University, Hefei 230601, China
| | - Ao Li
- Department of Orthopaedics, The Second Affiliated Hospital of Anhui Medical University, Hefei 230601, China; Institute of Orthopaedics, Research Center for Translational Medicine, The Second Affiliated Hospital of Anhui Medical University, Hefei 230601, China
| | - Juehua Jing
- Department of Orthopaedics, The Second Affiliated Hospital of Anhui Medical University, Hefei 230601, China; Institute of Orthopaedics, Research Center for Translational Medicine, The Second Affiliated Hospital of Anhui Medical University, Hefei 230601, China.
| | - Meige Zheng
- Department of Orthopaedics, The Second Affiliated Hospital of Anhui Medical University, Hefei 230601, China; Institute of Orthopaedics, Research Center for Translational Medicine, The Second Affiliated Hospital of Anhui Medical University, Hefei 230601, China.
| | - Dasheng Tian
- Department of Orthopaedics, The Second Affiliated Hospital of Anhui Medical University, Hefei 230601, China; Institute of Orthopaedics, Research Center for Translational Medicine, The Second Affiliated Hospital of Anhui Medical University, Hefei 230601, China.
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3
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Xiao Y, Chen Y, Huang S, He H, Hu N, Lin S, You Z. The reduction of microglial efferocytosis is concomitant with depressive-like behavior in CUMS-treated mice. J Affect Disord 2024; 352:76-86. [PMID: 38360363 DOI: 10.1016/j.jad.2024.02.045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 02/07/2024] [Accepted: 02/12/2024] [Indexed: 02/17/2024]
Abstract
BACKGROUND Microglial efferocytosis plays a crucial role in facilitating and sustaining homeostasis in the central nervous system, and it is involved in neuropsychiatric disorders. How microglial efferocytosis is affected under the condition of major depressive disorder (MDD) remains elusive. In this study, we hypothesized that microglial efferocytosis in the hippocampus is impaired in the chronic unpredicted mild stress (CUMS) model of MDD, which is involved in the development of MDD. METHOD Depressive-like behavior in adult male mice was induced by CUMS and confirmed by behavioral tests. Microglial efferocytosis was evaluated using immunofluorescence staining of hippocampal slices and primary microglia co-cultured with apoptotic cells. The protein and mRNA levels of phagocytosis-related molecules and inflammation-related cytokines were detected using western blotting and RT-qPCR, respectively. Annexin V was injected to mimic impairment of microglial efferocytosis. TREM2-siRNA was further used on primary microglia to examine efferocytosis-related signaling pathways. RESULTS Microglia were activated and the expression of proinflammatory cytokines was increased in CUMS mice, while microglial efferocytosis and efferocytosis-related molecules were decreased. Inhibition of the TREM2/Rac1 pathway impaired microglial efferocytosis. Annexin V injection inhibited microglial efferocytosis, increased inflammation in the hippocampus and depressive-like behavior. LIMITATIONS The potential antidepressant effect of the upregulation of the TREM2/Rac1 pathway was not evaluated. CONCLUSIONS Impairment of microglial efferocytosis is involved in the development of depressive-like behavior, with downregulation of the TREM2/Rac1 pathway and increased inflammation. These results may increase our understanding of the pathophysiological mechanisms associated with MDD and provide novel targets for therapeutic interventions.
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Affiliation(s)
- Ying Xiao
- Laboratory of Aging Research, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China; Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China.
| | - Yuxiang Chen
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Shiqi Huang
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Hui He
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Nan Hu
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Shanyu Lin
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Zili You
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 611731, China.
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4
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Ge Y, Yang C, Zadeh M, Sprague SM, Lin YD, Jain HS, Determann BF, Roth WH, Palavicini JP, Larochelle J, Candelario-Jalil E, Mohamadzadeh M. Functional regulation of microglia by vitamin B12 alleviates ischemic stroke-induced neuroinflammation in mice. iScience 2024; 27:109480. [PMID: 38715940 PMCID: PMC11075062 DOI: 10.1016/j.isci.2024.109480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 12/14/2023] [Accepted: 03/08/2024] [Indexed: 05/12/2024] Open
Abstract
Ischemic stroke is the second leading cause of death and disability worldwide, and efforts to prevent stroke, mitigate secondary neurological damage, and promote neurological recovery remain paramount. Recent findings highlight the critical importance of microbiome-related metabolites, including vitamin B12 (VB12), in alleviating toxic stroke-associated neuroinflammation. Here, we showed that VB12 tonically programmed genes supporting microglial cell division and activation and critically controlled cellular fatty acid metabolism in homeostasis. Intriguingly, VB12 promoted mitochondrial transcriptional and metabolic activities and significantly restricted stroke-associated gene alterations in microglia. Furthermore, VB12 differentially altered the functions of microglial subsets during the acute phase of ischemic stroke, resulting in reduced brain damage and improved neurological function. Pharmacological depletion of microglia before ischemic stroke abolished VB12-mediated neurological improvement. Thus, our preclinical studies highlight the relevance of VB12 in the functional programming of microglia to alleviate neuroinflammation, minimize ischemic injury, and improve host neurological recovery after ischemic stroke.
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Affiliation(s)
- Yong Ge
- Department of Microbiology, Immunology & Molecular Genetics, University of Texas Health, San Antonio, TX, USA
| | - Changjun Yang
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Mojgan Zadeh
- Department of Microbiology, Immunology & Molecular Genetics, University of Texas Health, San Antonio, TX, USA
| | - Shane M. Sprague
- Department of Neurosurgery, University of Texas Health, San Antonio, TX, USA
| | - Yang-Ding Lin
- Department of Microbiology, Immunology & Molecular Genetics, University of Texas Health, San Antonio, TX, USA
| | - Heetanshi Sanjay Jain
- Department of Microbiology, Immunology & Molecular Genetics, University of Texas Health, San Antonio, TX, USA
| | | | - William H. Roth
- Department of Neurology, University of Chicago Medical Center, Chicago, IL, USA
| | - Juan Pablo Palavicini
- Department of Microbiology, Immunology & Molecular Genetics, University of Texas Health, San Antonio, TX, USA
| | - Jonathan Larochelle
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Eduardo Candelario-Jalil
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Mansour Mohamadzadeh
- Department of Microbiology, Immunology & Molecular Genetics, University of Texas Health, San Antonio, TX, USA
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5
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Schwartz RE, Conboy IM. Non-Intrinsic, Systemic Mechanisms of Cellular Senescence. Cells 2023; 12:2769. [PMID: 38132089 PMCID: PMC10741531 DOI: 10.3390/cells12242769] [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: 10/28/2023] [Revised: 11/30/2023] [Accepted: 12/01/2023] [Indexed: 12/23/2023] Open
Abstract
Cellular senescence is believed to contribute to aging and disease through the activity of secreted factors that promote inflammation, remodel the extracellular matrix, and adversely modify the behavior of non-senescent cells. While the markers and properties of senescent cells are still under investigation, it is postulated that cellular senescence manifests in vivo as the consequence of cellular damage that accumulates and becomes exacerbated with time. Yet, the notions that senescence has a solely intrinsic and time-dependent nature are questioned by the rapid induction of senescence in young mice and young cells in vitro by exposure to blood from aged animals. Here, we review some of the research on the systemically present factors that increase with age and may contribute to extrinsically induced senescence or "bystander senescence". These include proteins, reactive oxygen species, lipids, and nucleic acids, which may be present in individual soluble form, in vesicles, and in non-membranous multi-component macromolecules.
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Affiliation(s)
| | - Irina M. Conboy
- Department of Bioengineering, University of California Berkeley, Berkeley, CA 94720, USA;
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Endo A, Imai J, Izumi T, Kawana Y, Sugawara H, Kohata M, Seike J, Kubo H, Komamura H, Sato T, Asai Y, Hosaka S, Kodama S, Takahashi K, Kaneko K, Katagiri H. Phagocytosis by macrophages promotes pancreatic β cell mass reduction after parturition in mice. Dev Cell 2023; 58:1819-1829.e5. [PMID: 37716356 DOI: 10.1016/j.devcel.2023.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 03/07/2023] [Accepted: 08/01/2023] [Indexed: 09/18/2023]
Abstract
Elucidating the mechanism(s) modulating appropriate tissue size is a critical biological issue. Pancreatic β cells increase during pregnancy via cellular proliferation, but how β cells promptly decrease to the original amount after parturition remains unclear. Herein, we demonstrate the role and mechanism of macrophage accumulation in this process. In the final stage of pregnancy, HTR1D signaling upregulates murine β cell CXCL10, thereby promoting macrophage accumulation in pancreatic islets via the CXCL10-CXCR3 axis. Blocking this mechanism by administering an HTR1D antagonist or the CXCR3 antibody and depleting islet macrophages inhibited postpartum β cell mass reduction. β cells engulfed by macrophages increased in postpartum islets, but Annexin V administration suppressed this engulfment and the postpartum β cell mass reduction, indicating the accumulated macrophages to phagocytose β cells. This mechanism contributes to both maintenance of appropriate β cell mass and glucose homeostasis promptly adapting to reduced systemic insulin demand after parturition.
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Affiliation(s)
- Akira Endo
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Junta Imai
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan.
| | - Tomohito Izumi
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Yohei Kawana
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Hiroto Sugawara
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Masato Kohata
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Junro Seike
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Haremaru Kubo
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Hiroshi Komamura
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Toshihiro Sato
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Yoichiro Asai
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Shinichiro Hosaka
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Shinjiro Kodama
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Kei Takahashi
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Keizo Kaneko
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Hideki Katagiri
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
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Olpe C, Jessberger S. Cell population dynamics in the course of adult hippocampal neurogenesis: Remaining unknowns. Hippocampus 2023; 33:402-411. [PMID: 36256493 DOI: 10.1002/hipo.23475] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 09/26/2022] [Accepted: 09/30/2022] [Indexed: 11/08/2022]
Abstract
Neural stem cells (NSCs) generate new neurons throughout life in the mammalian hippocampus. The distinct developmental steps in the course of adult neurogenesis, including NSC activation, expansion, and neuronal integration, are increasingly well characterized down to the molecular level. However, substantial gaps remain in our knowledge about regulators and mechanisms involved in this biological process. This review highlights three long-standing unknowns. First, we discuss potency and identity of NSCs and the quest for a unifying model of short- and long-term self-renewal dynamics. Next, we examine cell death, specifically focusing on the early demise of newborn cells. Then, we outline the current knowledge on cell integration dynamics, discussing which (if any) neurons are replaced by newly added neurons in the hippocampal circuits. For each of these unknowns, we summarize the trajectory of studies leading to the current state of knowledge. Finally, we offer suggestions on how to fill the remaining gaps by taking advantage of novel technology to reveal currently hidden secrets in the course of adult hippocampal neurogenesis.
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Affiliation(s)
- Cora Olpe
- Brain Research Institute, Faculties of Medicine and Science, University of Zurich, Zurich, Switzerland
| | - Sebastian Jessberger
- Brain Research Institute, Faculties of Medicine and Science, University of Zurich, Zurich, Switzerland
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8
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Organization of self-advantageous niche by neural stem/progenitor cells during development via autocrine VEGF-A under hypoxia. Inflamm Regen 2023; 43:8. [PMID: 36726165 PMCID: PMC9893632 DOI: 10.1186/s41232-022-00254-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 12/27/2022] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND Tissue stem cells are confined within a special microenvironment called niche. Stem cells in such a niche are supplied with nutrients and contacted by other cells to maintain their characters and also to keep or expand their population size. Besides, oxygen concentration is a key factor for stem cell niche. Adult neural stem/progenitor cells (NSPCs) are known to reside in a hypoxic niche. Oxygen concentration levels are lower in fetal organs including brain than maternal organs. However, how fetal NSPCs adapt to the hypoxic environment during brain development, particularly before pial and periventricular vessels start to invade the telencephalon, has not fully been elucidated. METHODS NSPCs were prepared from cerebral cortices of embryonic day (E) 11.5 or E14.5 mouse embryos and were enriched by 4-day incubation with FGF2. To evaluate NSPC numbers, neurosphere formation assay was performed. Sparsely plated NSPCs were cultured to form neurospheres under the hypoxic (1% O2) or normoxic condition. VEGF-A secreted from NSPCs in the culture medium was measured by ELISA. VEGF-A expression and Hif-1a in the developing brain was investigated by in situ hybridization and immunohistochemistry. RESULTS Here we show that neurosphere formation of embryonic NSPCs is dramatically increased under hypoxia compared to normoxia. Vegf-A gene expression and its protein secretion were both up-regulated in the NSPCs under hypoxia. Either recombinant VEGF-A or conditioned medium of the hypoxic NSPC culture enhanced the neurosphere forming ability of normoxic NSPCs, which was attenuated by a VEGF-A signaling inhibitor. Furthermore, in the developing brain, VEGF-A was strongly expressed in the VZ where NSPCs are confined. CONCLUSIONS We show that NSPCs secret VEGF-A in an autocrine fashion to efficiently maintain themselves under hypoxic developmental environment. Our results suggest that NSPCs have adaptive potential to respond to hypoxia to organize self-advantageous niche involving VEGF-A when the vascular system is immature.
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Dittmann NL, Torabi P, Watson AES, Yuzwa SA, Voronova A. Culture Protocol and Transcriptomic Analysis of Murine SVZ NPCs and OPCs. Stem Cell Rev Rep 2023; 19:983-1000. [PMID: 36617597 DOI: 10.1007/s12015-022-10492-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/09/2022] [Indexed: 01/10/2023]
Abstract
The mammalian adult brain contains two neural stem and precursor (NPC) niches: the subventricular zone [SVZ] lining the lateral ventricles and the subgranular zone [SGZ] in the hippocampus. From these, SVZ NPCs represent the largest NPC pool. While SGZ NPCs typically only produce neurons and astrocytes, SVZ NPCs produce neurons, astrocytes and oligodendrocytes throughout life. Of particular importance is the generation and replacement of oligodendrocytes, the only myelinating cells of the central nervous system (CNS). SVZ NPCs contribute to myelination by regenerating the parenchymal oligodendrocyte precursor cell (OPC) pool and by differentiating into oligodendrocytes in the developing and demyelinated brain. The neurosphere assay has been widely adopted by the scientific community to facilitate the study of NPCs in vitro. Here, we present a streamlined protocol for culturing postnatal and adult SVZ NPCs and OPCs from primary neurosphere cells. We characterize the purity and differentiation potential as well as provide RNA-sequencing profiles of postnatal SVZ NPCs, postnatal SVZ OPCs and adult SVZ NPCs. We show that primary neurospheres cells generated from postnatal and adult SVZ differentiate into neurons, astrocytes and oligodendrocytes concurrently and at comparable levels. SVZ OPCs are generated by subjecting primary neurosphere cells to OPC growth factors fibroblast growth factor (FGF) and platelet-derived growth factor-AA (PDGF-AA). We further show SVZ OPCs can differentiate into oligodendrocytes in the absence and presence of thyroid hormone T3. Transcriptomic analysis confirmed the identities of each cell population and revealed novel immune and signalling pathways expressed in an age and cell type specific manner.
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Affiliation(s)
- Nicole L Dittmann
- Department of Medical Genetics, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB, T6G 2H7, Canada.,Neuroscience and Mental Health Institute, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB, T6G 2E1, Canada
| | - Pouria Torabi
- Department of Medical Genetics, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB, T6G 2H7, Canada
| | - Adrianne E S Watson
- Department of Medical Genetics, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB, T6G 2H7, Canada
| | - Scott A Yuzwa
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Anastassia Voronova
- Department of Medical Genetics, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB, T6G 2H7, Canada. .,Neuroscience and Mental Health Institute, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB, T6G 2E1, Canada. .,Women and Children's Health Research Institute5-083 Edmonton Clinic Health Academy, University of Alberta, 11405 87 Avenue NW, Edmonton, Alberta, T6G 1C9, Canada. .,Department of Cell Biology, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB, T6G 2H7, Canada. .,Multiple Sclerosis Centre, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB, T6G 2H7, Canada.
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10
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de Almeida MMA, Goodkey K, Voronova A. Regulation of microglia function by neural stem cells. Front Cell Neurosci 2023; 17:1130205. [PMID: 36937181 PMCID: PMC10014810 DOI: 10.3389/fncel.2023.1130205] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 02/13/2023] [Indexed: 03/05/2023] Open
Abstract
Neural stem and precursor cells (NPCs) build and regenerate the central nervous system (CNS) by maintaining their pool (self-renewal) and differentiating into neurons, astrocytes, and oligodendrocytes (multipotency) throughout life. This has inspired research into pro-regenerative therapies that utilize transplantation of exogenous NPCs or recruitment of endogenous adult NPCs for CNS regeneration and repair. Recent advances in single-cell RNA sequencing and other "omics" have revealed that NPCs express not just traditional progenitor-related genes, but also genes involved in immune function. Here, we review how NPCs exert immunomodulatory function by regulating the biology of microglia, immune cells that are present in NPC niches and throughout the CNS. We discuss the role of transplanted and endogenous NPCs in regulating microglia fates, such as survival, proliferation, migration, phagocytosis and activation, in the developing, injured and degenerating CNS. We also provide a literature review on NPC-specific mediators that are responsible for modulating microglia biology. Our review highlights the immunomodulatory properties of NPCs and the significance of these findings in the context of designing pro-regenerative therapies for degenerating and diseased CNS.
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Affiliation(s)
- Monique M. A. de Almeida
- Department of Medical Genetics, Faculty of Medicine & Dentistry, Edmonton, AB, Canada
- Faculty of Medicine & Dentistry, Neuroscience and Mental Health Institute, Edmonton, AB, Canada
| | - Kara Goodkey
- Department of Medical Genetics, Faculty of Medicine & Dentistry, Edmonton, AB, Canada
- Women and Children’s Health Research Institute, 5-083 Edmonton Clinic Health Academy, University of Alberta, Edmonton, AB, Canada
| | - Anastassia Voronova
- Department of Medical Genetics, Faculty of Medicine & Dentistry, Edmonton, AB, Canada
- Faculty of Medicine & Dentistry, Neuroscience and Mental Health Institute, Edmonton, AB, Canada
- Women and Children’s Health Research Institute, 5-083 Edmonton Clinic Health Academy, University of Alberta, Edmonton, AB, Canada
- Department of Cell Biology, Faculty of Medicine & Dentistry, Edmonton, AB, Canada
- Multiple Sclerosis Centre and Department of Cell Biology, Faculty of Medicine & Dentistry, Edmonton, AB, Canada
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11
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Neural precursor cells tune striatal connectivity through the release of IGFBPL1. Nat Commun 2022; 13:7579. [PMID: 36482070 PMCID: PMC9731988 DOI: 10.1038/s41467-022-35341-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 11/30/2022] [Indexed: 12/13/2022] Open
Abstract
The adult brain retains over life endogenous neural stem/precursor cells (eNPCs) within the subventricular zone (SVZ). Whether or not these cells exert physiological functions is still unclear. In the present work, we provide evidence that SVZ-eNPCs tune structural, electrophysiological, and behavioural aspects of striatal function via secretion of insulin-like growth factor binding protein-like 1 (IGFBPL1). In mice, selective ablation of SVZ-eNPCs or selective abrogation of IGFBPL1 determined an impairment of striatal medium spiny neuron morphology, a higher failure rate in GABAergic transmission mediated by fast-spiking interneurons, and striatum-related behavioural dysfunctions. We also found IGFBPL1 expression in the human SVZ, foetal and induced-pluripotent stem cell-derived NPCs. Finally, we found a significant correlation between SVZ damage, reduction of striatum volume, and impairment of information processing speed in neurological patients. Our results highlight the physiological role of adult SVZ-eNPCs in supporting cognitive functions by regulating striatal neuronal activity.
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12
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Chen P, Lin MH, Li YX, Huang ZJ, Rong YY, Lin QS, Ye ZC. Bexarotene enhances astrocyte phagocytosis via ABCA1-mediated pathways in a mouse model of subarachnoid hemorrhage. Exp Neurol 2022; 358:114228. [PMID: 36108713 DOI: 10.1016/j.expneurol.2022.114228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 08/31/2022] [Accepted: 09/08/2022] [Indexed: 11/04/2022]
Abstract
BACKGROUND AND PURPOSE Enhancing phagocytosis can facilitate the removal of inflammatory molecules, limit the toxicity of dead cells and debris, and promote recovery after brain injury. In this study, we aimed to explore the role of bexarotene (Bex), a retinoid X receptor (RXR) agonist, in promoting astrocyte phagocytosis and neurobehavioral recovery after subarachnoid hemorrhage (SAH). METHODS Mice SAH model was induced by pre-chiasmatic injection of blood. Modified Garcia score, novel object recognition, rotarod test, and Morris water maze were performed to assess neurological function. Immunofluorescence and electron microscopy were used to evaluate astrocyte phagocytosis in vivo. In addition, ABCA1/MEGF10&GULP1, the primary astrocyte phagocytosis pathway, were stimulated by Bex or suppressed by HX531 (a RXR antagonist) to evaluate their impacts on astrocyte phagocytosis and neurological recovery. RESULTS Astrocytes phagocytosis of blood components were observed in mice after SAH induction, which is further increased by Bex treatment. Bex dramatically attenuated neuroinflammation, reduced brain edema, improved early neurological performance and promoted neurocognitive recovery. Meanwhile, Bex decreased neurotoxic reactive astrocytes and preserved neurogenesis after SAH. Bex increased the expression of astrocyte phagocytosis-related proteins ABCA1, MEGF10, and GULP1. Bex also increased the lysosomal processing of engulfed blood components in astrocytes. Moreover, Bex significantly promoted astrocytes to phagocytize debris in vitro by increasing the expression of ABCA1, MEGF10 and GULP1, while HX531 inhibited astrocyte phagocytosis and decreased these protein levels. CONCLUSIONS Bex enhanced astrocyte phagocytosis through the ABCA1-mediated pathways, and promoted neurobehavior recovery in mice after SAH induction.
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Affiliation(s)
- Ping Chen
- Department of Anesthesiology, Anesthesiology Research Institute, the First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian, China; Fujian Provincial Key Laboratory of Brain Aging and Neurodegenerative Diseases, The School of Basic Medical Sciences, Fujian Medical University, China
| | - Mou-Hui Lin
- Fujian Provincial Key Laboratory of Brain Aging and Neurodegenerative Diseases, The School of Basic Medical Sciences, Fujian Medical University, China
| | - Yu-Xi Li
- Fujian Provincial Key Laboratory of Brain Aging and Neurodegenerative Diseases, The School of Basic Medical Sciences, Fujian Medical University, China
| | - Zhi-Jie Huang
- Fujian Provincial Key Laboratory of Brain Aging and Neurodegenerative Diseases, The School of Basic Medical Sciences, Fujian Medical University, China
| | - Yu-You Rong
- Fujian Provincial Key Laboratory of Brain Aging and Neurodegenerative Diseases, The School of Basic Medical Sciences, Fujian Medical University, China
| | - Qing-Song Lin
- Department of Neurosurgery, Neurosurgery Research Institute, the First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian, China.
| | - Zu-Cheng Ye
- Fujian Provincial Key Laboratory of Brain Aging and Neurodegenerative Diseases, The School of Basic Medical Sciences, Fujian Medical University, China.
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13
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Synaptic pruning through glial synapse engulfment upon motor learning. Nat Neurosci 2022; 25:1458-1469. [PMID: 36319770 DOI: 10.1038/s41593-022-01184-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 09/15/2022] [Indexed: 11/06/2022]
Abstract
Synaptic pruning is a fundamental process of neuronal circuit refinement in learning and memory. Accumulating evidence suggests that glia participates in sculpting the neuronal circuits through synapse engulfment. However, whether glial involvement in synaptic pruning has a role in memory formation remains elusive. Using newly developed phagocytosis reporter mice and three-dimensional ultrastructural characterization, we found that synaptic engulfment by cerebellar Bergmann glia (BG) frequently occurred upon cerebellum-dependent motor learning in mice. We observed increases in pre- and postsynaptic nibbling by BG along with a reduction in spine volume after learning. Pharmacological blockade of engulfment with Annexin V inhibited both the spine volume reduction and overnight improvement of motor adaptation. These results indicate that BG contribute to the refinement of the mature cerebellar cortical circuit through synaptic engulfment during motor learning.
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14
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Microglial debris is cleared by astrocytes via C4b-facilitated phagocytosis and degraded via RUBICON-dependent noncanonical autophagy in mice. Nat Commun 2022; 13:6233. [PMID: 36280666 PMCID: PMC9592609 DOI: 10.1038/s41467-022-33932-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 10/06/2022] [Indexed: 01/18/2023] Open
Abstract
Microglia are important immune cells in the central nervous system (CNS) that undergo turnover throughout the lifespan. If microglial debris is not removed in a timely manner, accumulated debris may influence CNS function. Clearance of microglial debris is crucial for CNS homeostasis. However, underlying mechanisms remain obscure. We here investigate how dead microglia are removed. We find that although microglia can phagocytose microglial debris in vitro, the territory-dependent competition hinders the microglia-to-microglial debris engulfment in vivo. In contrast, microglial debris is mainly phagocytosed by astrocytes in the brain, facilitated by C4b opsonization. The engulfed microglial fragments are then degraded in astrocytes via RUBICON-dependent LC3-associated phagocytosis (LAP), a form of noncanonical autophagy. Interference with C4b-mediated engulfment and subsequent LAP disrupt the removal and degradation of microglial debris, respectively. Together, we elucidate the cellular and molecular mechanisms of microglial debris removal in mice, extending the knowledge on the maintenance of CNS homeostasis.
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15
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Mahmoudi A, Moadab F, Safdarian E, Navashenaq JG, Rezaee M, Gheibihayat SM. MicroRNAs and Efferocytosis: Implications for Diagnosis and Therapy. Mini Rev Med Chem 2022; 22:2641-2660. [PMID: 35362375 DOI: 10.2174/1389557522666220330150937] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 09/24/2021] [Accepted: 01/19/2022] [Indexed: 11/22/2022]
Abstract
About 10-100 billion cells are generated in the human body in a day, and accordingly, 10-100 billion cells predominantly die for maintaining homeostasis. Dead cells generated by apoptosis are also rapidly engulfed by macrophages (Mθs) to be degraded. In case of the inefficient engulfment of apoptotic cells (ACs) via Mθs, they experience secondary necrosis and thus release intracellular materials, which display damage-associated molecular patterns (DAMPs) and result in diseases. Over the last decades, researchers have also reflected on the significant contribution of microRNAs (miRNAs) to autoimmune diseases through the regulation of Mθs functions. Moreover, miRNAs have shown intricate involvement with completely adjusting basic Mθs functions, such as phagocytosis, inflammation, efferocytosis, tumor promotion, and tissue repair. In this review, the mechanism of efferocytosis containing "Find-Me", "Eat-Me", and "Digest-Me" signals is summarized and the biogenesis of miRNAs is briefly described. Finally, the role of miRNAs in efferocytosis is discussed. It is concluded that miRNAs represent promising treatments and diagnostic targets in impaired phagocytic clearance, which leads to different diseases.
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Affiliation(s)
- Ali Mahmoudi
- Department of medical biotechnology and nanotechnology, faculty of medicine, Mashhad University of Medical science, Iran
| | - Fatemeh Moadab
- Medical student, Student Research Committee, Rafsanjan University of Medical Sciences, Rafsanjan, Iran
| | - Esmat Safdarian
- Legal Medicine Research Center, Legal Medicine Organization, Tehran Iran
| | | | - Mehdi Rezaee
- Department of Medical Biotechnology, School of Advanced Technologies, Shahrekord University of Medical Sciences, Shahrekord, Iran;
- Cellular and Molecular Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Sciences, Shahrekord, Iran
| | - Seyed Mohammad Gheibihayat
- Department of Medical Biotechnology, School of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
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16
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Li X, Peng X, Yang S, Wei S, Fan Q, Liu J, Yang L, Li H. Targeting tumor innervation: premises, promises, and challenges. Cell Death Dis 2022; 8:131. [PMID: 35338118 PMCID: PMC8956600 DOI: 10.1038/s41420-022-00930-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 12/17/2021] [Accepted: 02/28/2022] [Indexed: 01/03/2023]
Abstract
A high intratumoral nerve density is correlated with poor survival, high metastasis, and high recurrence across multiple solid tumor types. Recent research has revealed that cancer cells release diverse neurotrophic factors and exosomes to promote tumor innervation, in addition, infiltrating nerves can also mediate multiple tumor biological processes via exosomes and neurotransmitters. In this review, through seminal studies establishing tumor innervation, we discuss the communication between peripheral nerves and tumor cells in the tumor microenvironment (TME), and revealed the nerve-tumor regulation mechanisms on oncogenic process, angiogenesis, lymphangiogenesis, and immunity. Finally, we discussed the promising directions of ‘old drugs newly used’ to target TME communication and clarified a new line to prevent tumor malignant capacity.
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Affiliation(s)
- Xinyu Li
- Department of General Surgery, The Fourth Affiliated Hospital, China Medical University, Shenyang, 110032, China
| | - Xueqiang Peng
- Department of General Surgery, The Fourth Affiliated Hospital, China Medical University, Shenyang, 110032, China
| | - Shuo Yang
- Department of General Surgery, The Fourth Affiliated Hospital, China Medical University, Shenyang, 110032, China
| | - Shibo Wei
- Department of General Surgery, The Fourth Affiliated Hospital, China Medical University, Shenyang, 110032, China
| | - Qing Fan
- Department of General Surgery, The Fourth Affiliated Hospital, China Medical University, Shenyang, 110032, China
| | - Jingang Liu
- Department of General Surgery, The Fourth Affiliated Hospital, China Medical University, Shenyang, 110032, China
| | - Liang Yang
- Department of General Surgery, The Fourth Affiliated Hospital, China Medical University, Shenyang, 110032, China.
| | - Hangyu Li
- Department of General Surgery, The Fourth Affiliated Hospital, China Medical University, Shenyang, 110032, China.
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17
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Wan T, Zhu W, Zhao Y, Zhang X, Ye R, Zuo M, Xu P, Huang Z, Zhang C, Xie Y, Liu X. Astrocytic phagocytosis contributes to demyelination after focal cortical ischemia in mice. Nat Commun 2022; 13:1134. [PMID: 35241660 PMCID: PMC8894352 DOI: 10.1038/s41467-022-28777-9] [Citation(s) in RCA: 49] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 02/11/2022] [Indexed: 01/24/2023] Open
Abstract
Ischemic stroke can cause secondary myelin damage in the white matter distal to the primary injury site. The contribution of astrocytes during secondary demyelination and the underlying mechanisms are unclear. Here, using a mouse of distal middle cerebral artery occlusion, we show that lipocalin-2 (LCN2), enriched in reactive astrocytes, expression increases in nonischemic areas of the corpus callosum upon injury. LCN2-expressing astrocytes acquire a phagocytic phenotype and are able to uptake myelin. Myelin removal is impaired in Lcn2−/− astrocytes. Inducing re-expression of truncated LCN2(Δ2–20) in astrocytes restores phagocytosis and leads to progressive demyelination in Lcn2−/− mice. Co-immunoprecipitation experiments show that LCN2 binds to low-density lipoprotein receptor-related protein 1 (LRP1) in astrocytes. Knockdown of Lrp1 reduces LCN2-induced myelin engulfment by astrocytes and reduces demyelination. Altogether, our findings suggest that LCN2/LRP1 regulates astrocyte-mediated myelin phagocytosis in a mouse model of ischemic stroke. Ischemic stroke can cause secondary demyelination. Whether phagocytic astrocytes can contribute to such demyelination is unclear. Here, the authors show that lipocalin-2 (LCN-2) expression increased in astrocytes upon injury. LCN-2 expressing astrocytes acquire a phagocytic phenotype and contribute to secondary demyelination in a mouse model of ischemic stroke.
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Affiliation(s)
- Ting Wan
- Department of Neurology, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, 210000, China
| | - Wusheng Zhu
- Department of Neurology, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, 210000, China
| | - Ying Zhao
- Department of Neurology, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, 210000, China
| | - Xiaohao Zhang
- Department of Neurology, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, 210000, China
| | - Ruidong Ye
- Department of Neurology, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, 210000, China
| | - Meng Zuo
- Department of Neurology, Southwest Hospital and the First Affiliated Hospital, Army Medical University, Chongqing, 400000, China
| | - Pengfei Xu
- Stroke Center & Department of Neurology, The Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230036, Anhui, China
| | - Zhenqian Huang
- Department of Neurology, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, 210000, China
| | - Chunni Zhang
- Department of Clinical Laboratory, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, 210000, China.
| | - Yi Xie
- Department of Neurology, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, 210000, China.
| | - Xinfeng Liu
- Department of Neurology, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, 210000, China. .,Stroke Center & Department of Neurology, The Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230036, Anhui, China.
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18
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Liu KE, Raymond MH, Ravichandran KS, Kucenas S. Clearing Your Mind: Mechanisms of Debris Clearance After Cell Death During Neural Development. Annu Rev Neurosci 2022; 45:177-198. [PMID: 35226828 PMCID: PMC10157384 DOI: 10.1146/annurev-neuro-110920-022431] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Neurodevelopment and efferocytosis have fascinated scientists for decades. How an organism builds a nervous system that is precisely tuned for efficient behaviors and survival and how it simultaneously manages constant somatic cell turnover are complex questions that have resulted in distinct fields of study. Although neurodevelopment requires the overproduction of cells that are subsequently pruned back, very few studies marry these fields to elucidate the cellular and molecular mechanisms that drive nervous system development through the lens of cell clearance. In this review, we discuss these fields to highlight exciting areas of future synergy. We first review neurodevelopment from the perspective of overproduction and subsequent refinement and then discuss who clears this developmental debris and the mechanisms that control these events. We then end with how a more deliberate merger of neurodevelopment and efferocytosis could reframe our understanding of homeostasis and disease and discuss areas of future study. Expected final online publication date for the Annual Review of Neuroscience, Volume 45 is July 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Kendra E Liu
- Neuroscience Graduate Program, University of Virginia, Charlottesville, Virginia, USA; .,Program in Fundamental Neuroscience, University of Virginia, Charlottesville, Virginia, USA
| | - Michael H Raymond
- Neuroscience Graduate Program, University of Virginia, Charlottesville, Virginia, USA; .,Center for Clearance, University of Virginia, Charlottesville, Virginia, USA
| | - Kodi S Ravichandran
- Neuroscience Graduate Program, University of Virginia, Charlottesville, Virginia, USA; .,Center for Clearance, University of Virginia, Charlottesville, Virginia, USA.,Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA.,VIB-UGent Center for Inflammation Research and the Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Sarah Kucenas
- Neuroscience Graduate Program, University of Virginia, Charlottesville, Virginia, USA; .,Program in Fundamental Neuroscience, University of Virginia, Charlottesville, Virginia, USA.,Department of Biology, University of Virginia, Charlottesville, Virginia, USA
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19
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Ihunwo AO, Perego J, Martino G, Vicenzi E, Panina-Bordignon P. Neurogenesis and Viral Infection. Front Immunol 2022; 13:826091. [PMID: 35251006 PMCID: PMC8891128 DOI: 10.3389/fimmu.2022.826091] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 01/20/2022] [Indexed: 12/26/2022] Open
Abstract
Neural stem cells (NSCs) are multipotent stem cells that reside in the fetal and adult mammalian brain, which can self-renew and differentiate into neurons and supporting cells. Intrinsic and extrinsic cues, from cells in the local niche and from distant sites, stringently orchestrates the self-renewal and differentiation competence of NSCs. Ample evidence supports the important role of NSCs in neuroplasticity, aging, disease, and repair of the nervous system. Indeed, activation of NSCs or their transplantation into injured areas of the central nervous system can lead to regeneration in animal models. Viral invasion of NSCs can negatively affect neurogenesis and synaptogenesis, with consequent cell death, impairment of cell cycle progression, early differentiation, which cause neural progenitors depletion in the cortical layer of the brain. Herein, we will review the current understanding of Zika virus (ZIKV) infection of the fetal brain and the NSCs, which are the preferential population targeted by ZIKV. Furthermore, the potential neurotropic properties of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which may cause direct neurological damage, will be discussed.
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Affiliation(s)
- Amadi Ogonda Ihunwo
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Jessica Perego
- Neuroimmunology Unit, Division of Neuroscience, San Raffaele Vita-Salute University and IRCCS San Raffaele Hospital, Milan, Italy
| | - Gianvito Martino
- Neuroimmunology Unit, Division of Neuroscience, San Raffaele Vita-Salute University and IRCCS San Raffaele Hospital, Milan, Italy
| | - Elisa Vicenzi
- Viral Pathogenesis and Biosafety Unit, Division of Immunology, Transplantation and Infectious Disesases, IRCCS San Raffaele Hospital, Milan, Italy
| | - Paola Panina-Bordignon
- Neuroimmunology Unit, Division of Neuroscience, San Raffaele Vita-Salute University and IRCCS San Raffaele Hospital, Milan, Italy
- *Correspondence: Paola Panina-Bordignon,
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20
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Xiong H, Chen Z, Zhao J, Li W, Zhang S. TNF-α/ENO1 signaling facilitates testicular phagocytosis by directly activating Elmo1 gene expression in mouse Sertoli cells. FEBS J 2021; 289:2809-2827. [PMID: 34919331 DOI: 10.1111/febs.16326] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 10/10/2021] [Accepted: 12/15/2021] [Indexed: 11/27/2022]
Abstract
Phagocytic clearance of apoptotic germ cells (GCs), as well as residual bodies (RBs) released from developing spermatids, is critical for Sertoli cells (SCs) to maintain inner environment homeostasis within testis. However, the molecular mechanisms controlling the phagocytosis are ill defined. Here, we identify a new role for alpha-enolase (ENO1), a key enzyme during glycolysis, as a molecule that facilitates testicular phagocytosis via transactivation of the engulfment and cell motility 1 (Elmo1) gene. Using immunohistochesmitry and double-labeling immunofluorescence, ENO1 was observed to be expressed exclusively in the nuclei of SCs and its expression correlated with the completion of Sertoli cell differentiation. By incubating TM4 cells with different pharmacological inhibitors and establishing TM4Tnfr1-/- cells, we demonstrated that Sertoli cell-specific expression of ENO1 was under a delicate paracrine control from apoptotic GCs. In turn, persistent blockade of ENO1 expression by a validated siRNA protocol resulted in the disturbance of spermatogenesis and impairment of male fertility. Furthermore, using chromatin immunoprecipitation, electrophoretic mobility shift assay and luciferase reporter assay, we showed that in the presence of apoptotic GCs, ENO1 binds to the distal region of the Elmo1 promoter and facilitates transactivation of the Elmo1 gene. In agreement, overexpression of ELMO1 ameliorated ENO1 deficiency-induced impairment of phagocytosis in TM4 cells. These data reveal a novel role for Sertoli cell-specific expression of ENO1 in regulating phagocytosis in testis, identify TNF-α and ELMO1 as critical upstream and downstream factors in mediating ENO1 action, and have important implications for understanding paracrine control of Sertoli cell function by adjacent GCs.
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Affiliation(s)
- Hu Xiong
- Reproductive Medicine Center, Department of Gynecology and Obstetrics, Tangdu Hospital, Air Force Medical University, Xi'an, 710038, P.R.China
| | - Zhenzhen Chen
- Department of Human Anatomy, Histology and Embryology, Air Force Medical University, Xi'an, 710032, P.R.China
| | - Jie Zhao
- Department of Human Anatomy, Histology and Embryology, Air Force Medical University, Xi'an, 710032, P.R.China
| | - Wei Li
- Department of Human Anatomy, Histology and Embryology, Air Force Medical University, Xi'an, 710032, P.R.China
| | - Shun Zhang
- Reproductive Medicine Center, Department of Gynecology and Obstetrics, Tangdu Hospital, Air Force Medical University, Xi'an, 710038, P.R.China
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21
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Trzeciak A, Wang YT, Perry JSA. First we eat, then we do everything else: The dynamic metabolic regulation of efferocytosis. Cell Metab 2021; 33:2126-2141. [PMID: 34433074 PMCID: PMC8568659 DOI: 10.1016/j.cmet.2021.08.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 06/07/2021] [Accepted: 08/02/2021] [Indexed: 12/13/2022]
Abstract
Clearance of apoptotic cells, or "efferocytosis," is essential for diverse processes including embryonic development, tissue turnover, organ regeneration, and immune cell development. The human body is estimated to remove approximately 1% of its body mass via apoptotic cell clearance daily. This poses several intriguing cell metabolism problems. For instance, phagocytes such as macrophages must induce or suppress metabolic pathways to find, engulf, and digest apoptotic cells. Then, phagocytes must manage the potentially burdensome biomass of the engulfed apoptotic cell. Finally, phagocytes reside in complex tissue architectures that vary in nutrient availability, the types of dying cells or debris that require clearance, and the neighboring cells they interact with. Here, we review advances in our understanding of these three key areas of phagocyte metabolism. We end by proposing a model of efferocytosis that integrates recent findings and establishes a new paradigm for testing how efferocytosis prevents chronic inflammatory disease and autoimmunity.
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Affiliation(s)
- Alissa Trzeciak
- Immunology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Ya-Ting Wang
- Immunology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Justin Shaun Arnold Perry
- Immunology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA; Louis V. Gerstner Jr. Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, 417 E 68th Street, New York, NY 10065, USA; Department of Immunology and Microbial Pathogenesis, Weill Cornell Medical College, 417 E 68th Street, New York, NY 10065, USA.
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22
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Branch CL, Semenov GA, Wagner DN, Sonnenberg BR, Pitera AM, Bridge ES, Taylor SA, Pravosudov VV. The genetic basis of spatial cognitive variation in a food-caching bird. Curr Biol 2021; 32:210-219.e4. [PMID: 34735793 DOI: 10.1016/j.cub.2021.10.036] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 09/15/2021] [Accepted: 10/14/2021] [Indexed: 01/02/2023]
Abstract
Spatial cognition is used by most organisms to navigate their environment. Some species rely particularly heavily on specialized spatial cognition to survive, suggesting that a heritable component of cognition may be under natural selection. This idea remains largely untested outside of humans, perhaps because cognition in general is known to be strongly affected by learning and experience.1-4 We investigated the genetic basis of individual variation in spatial cognition used by non-migratory food-caching birds to recover food stores and survive harsh montane winters. Comparing the genomes of wild, free-living birds ranging from best to worst in their performance on a spatial cognitive task revealed significant associations with genes involved in neuron growth and development and hippocampal function. These results identify candidate genes associated with differences in spatial cognition and provide a critical link connecting individual variation in spatial cognition with natural selection.
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Affiliation(s)
- Carrie L Branch
- Cornell Lab of Ornithology, Cornell University, Ithaca, NY 14850, USA.
| | - Georgy A Semenov
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309, USA
| | - Dominique N Wagner
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309, USA
| | - Benjamin R Sonnenberg
- Ecology, Evolution, and Conservation Biology Graduate Program, University of Nevada, Reno, NV 89557, USA
| | - Angela M Pitera
- Ecology, Evolution, and Conservation Biology Graduate Program, University of Nevada, Reno, NV 89557, USA
| | - Eli S Bridge
- Ecology and Evolutionary Biology, University of Oklahoma, Norman, OK 73019, USA
| | - Scott A Taylor
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309, USA
| | - Vladimir V Pravosudov
- Ecology, Evolution, and Conservation Biology Graduate Program, University of Nevada, Reno, NV 89557, USA.
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23
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Physiological Roles of Apoptotic Cell Clearance: Beyond Immune Functions. Life (Basel) 2021; 11:life11111141. [PMID: 34833017 PMCID: PMC8621940 DOI: 10.3390/life11111141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 10/24/2021] [Accepted: 10/25/2021] [Indexed: 11/16/2022] Open
Abstract
The clearance of apoptotic cells is known to be a critical step in maintaining tissue and organism homeostasis. This process is rapidly/promptly mediated by recruited or resident phagocytes. Phagocytes that engulf apoptotic cells have been closely linked to the release of anti-inflammatory cytokines to eliminate inflammatory responses. Defective clearance of apoptotic cells can cause severe inflammation and autoimmune responses due to secondary necrosis of apoptotic cells. Recently accumulated evidence indicates that apoptotic cells and their clearance have important physiological roles in addition to immune-related functions. Herein, we review the current understanding of the mechanisms and fundamental roles of apoptotic cell clearance and the beneficial roles of apoptotic cells in physiological processes such as differentiation and development.
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24
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Rodrigues RS, Paulo SL, Moreira JB, Tanqueiro SR, Sebastião AM, Diógenes MJ, Xapelli S. Adult Neural Stem Cells as Promising Targets in Psychiatric Disorders. Stem Cells Dev 2021; 29:1099-1117. [PMID: 32723008 DOI: 10.1089/scd.2020.0100] [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: 11/12/2022] Open
Abstract
The development of new therapies for psychiatric disorders is of utmost importance, given the enormous toll these disorders pose to society nowadays. This should be based on the identification of neural substrates and mechanisms that underlie disease etiopathophysiology. Adult neural stem cells (NSCs) have been emerging as a promising platform to counteract brain damage. In this perspective article, we put forth a detailed view of how NSCs operate in the adult brain and influence brain homeostasis, having profound implications at both behavioral and functional levels. We appraise evidence suggesting that adult NSCs play important roles in regulating several forms of brain plasticity, particularly emotional and cognitive flexibility, and that NSC dynamics are altered upon brain pathology. Furthermore, we discuss the potential therapeutic value of utilizing adult endogenous NSCs as vessels for regeneration, highlighting their importance as targets for the treatment of multiple mental illnesses, such as affective disorders, schizophrenia, and addiction. Finally, we speculate on strategies to surpass current challenges in neuropsychiatric disease modeling and brain repair.
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Affiliation(s)
- Rui S Rodrigues
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Sara L Paulo
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - João B Moreira
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Sara R Tanqueiro
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Ana M Sebastião
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Maria J Diógenes
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Sara Xapelli
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
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25
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Wu KM, Zhang YR, Huang YY, Dong Q, Tan L, Yu JT. The role of the immune system in Alzheimer's disease. Ageing Res Rev 2021; 70:101409. [PMID: 34273589 DOI: 10.1016/j.arr.2021.101409] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Revised: 07/09/2021] [Accepted: 07/12/2021] [Indexed: 02/06/2023]
Abstract
Alzheimer's disease (AD) is the most common neurodegenerative disorder where the accumulation of amyloid plaques and the formation of tau tangles are the prominent pathological hallmarks. Increasing preclinical and clinical studies have revealed that different components of the immune system may act as important contributors to AD etiology and pathogenesis. The recognition of misfolded Aβ and tau by immune cells can trigger a series of complex immune responses in AD, and then lead to neuroinflammation and neurodegeneration. In parallel, genome-wide association studies have also identified several immune related loci associated with increased - risk of AD by interfering with the function of immune cells. Other immune related factors, such as impaired immunometabolism, defective meningeal lymphatic vessels and autoimmunity might also be involved in the pathogenesis of AD. Here, we review the data showing the alterations of immune cells in the AD trajectory and seek to demonstrate the crosstalk between the immune cell dysfunction and AD pathology. We then discuss the most relevant research findings in regards to the influences of gene susceptibility of immune cells for AD. We also consider impaired meningeal lymphatics, immunometabolism and autoimmune mechanisms in AD. In addition, immune related biomarkers and immunotherapies for AD are also mentioned in order to offer novel insights for future research.
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26
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Zhou H, Hu L, Li J, Ruan W, Cao Y, Zhuang J, Xu H, Peng Y, Zhang Z, Xu C, Yu Q, Li Y, Dou Z, Hu J, Wu X, Yu X, Gu C, Cao S, Yan F, Chen G. AXL kinase-mediated astrocytic phagocytosis modulates outcomes of traumatic brain injury. J Neuroinflammation 2021; 18:154. [PMID: 34233703 PMCID: PMC8264993 DOI: 10.1186/s12974-021-02201-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 06/22/2021] [Indexed: 11/23/2022] Open
Abstract
Background Complex changes in the brain microenvironment following traumatic brain injury (TBI) can cause neurological impairments for which there are few efficacious therapeutic interventions. The reactivity of astrocytes is one of the keys to microenvironmental changes, such as neuroinflammation, but its role and the molecular mechanisms that underpin it remain unclear. Methods Male C57BL/6J mice were subjected to the controlled cortical impact (CCI) to develop a TBI model. The specific ligand of AXL receptor tyrosine kinase (AXL), recombinant mouse growth arrest-specific 6 (rmGas6) was intracerebroventricularly administered, and selective AXL antagonist R428 was intraperitoneally applied at 30 min post-modeling separately. Post-TBI assessments included neurobehavioral assessments, transmission electron microscopy, immunohistochemistry, and western blotting. Real-time polymerase chain reaction (RT-PCR), siRNA transfection, and flow cytometry were performed for mechanism assessments in primary cultured astrocytes. Results AXL is upregulated mainly in astrocytes after TBI and promotes astrocytes switching to a phenotype that exhibits the capability of ingesting degenerated neurons or debris. As a result, this astrocytic transformation promotes the limitation of neuroinflammation and recovery of neurological dysfunction. Pharmacological inhibition of AXL in astrocytes significantly decreased astrocytic phagocytosis both in vivo and in primary astrocyte cultures, in contrast to the effect of treatment with the rmGas6. AXL activates the signal transducer and activator of the transcription 1 (STAT1) pathway thereby further upregulating ATP-binding cassette transporter 1 (ABCA1). Moreover, the supernatant from GAS6-depleted BV2 cells induced limited enhancement of astrocytic phagocytosis in vitro. Conclusion Our work establishes the role of AXL in the transformation of astrocytes to a phagocytic phenotype via the AXL/STAT1/ABCA1 pathway which contributes to the separation of healthy brain tissue from injury-induced cell debris, further ameliorating neuroinflammation and neurological impairments after TBI. Collectively, our findings provide a potential therapeutic target for TBI. Supplementary Information The online version contains supplementary material available at 10.1186/s12974-021-02201-3.
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Affiliation(s)
- Hang Zhou
- Department of Neurosurgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Jiefang Road88th, Hangzhou, 310016, China
| | - Libin Hu
- Department of Neurosurgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Jiefang Road88th, Hangzhou, 310016, China
| | - Jianru Li
- Department of Neurosurgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Jiefang Road88th, Hangzhou, 310016, China
| | - Wu Ruan
- Department of Burn and Plastic Surgery, Children's Hospital, Zhejiang University School of Medicine, No. 3333 Binsheng Road, Zhejiang, 310052, Hangzhou, China
| | - Yang Cao
- Department of Neurosurgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Jiefang Road88th, Hangzhou, 310016, China
| | - Jianfeng Zhuang
- Department of Neurosurgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Jiefang Road88th, Hangzhou, 310016, China
| | - Hangzhe Xu
- Department of Neurosurgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Jiefang Road88th, Hangzhou, 310016, China
| | - Yucong Peng
- Department of Neurosurgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Jiefang Road88th, Hangzhou, 310016, China
| | - Zhongyuan Zhang
- Department of Neurosurgery, Children's Hospital, Zhejiang University School of Medicine, No. 3333 Binsheng Road, Zhejiang, 310052, Hangzhou, China
| | - Chaoran Xu
- Department of Neurosurgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Jiefang Road88th, Hangzhou, 310016, China
| | - Qian Yu
- Department of Neurosurgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Jiefang Road88th, Hangzhou, 310016, China
| | - Yin Li
- Department of Neurosurgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Jiefang Road88th, Hangzhou, 310016, China
| | - Zhangqi Dou
- Department of Neurosurgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Jiefang Road88th, Hangzhou, 310016, China
| | - Junwen Hu
- Department of Neurosurgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Jiefang Road88th, Hangzhou, 310016, China
| | - Xinyan Wu
- Department of Neurosurgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Jiefang Road88th, Hangzhou, 310016, China
| | - Xiaobo Yu
- Department of Neurosurgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Jiefang Road88th, Hangzhou, 310016, China
| | - Chi Gu
- Department of Neurosurgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Jiefang Road88th, Hangzhou, 310016, China
| | - Shenglong Cao
- Department of Neurosurgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Jiefang Road88th, Hangzhou, 310016, China
| | - Feng Yan
- Department of Neurosurgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Jiefang Road88th, Hangzhou, 310016, China.
| | - Gao Chen
- Department of Neurosurgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Jiefang Road88th, Hangzhou, 310016, China.
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Cockram TOJ, Dundee JM, Popescu AS, Brown GC. The Phagocytic Code Regulating Phagocytosis of Mammalian Cells. Front Immunol 2021; 12:629979. [PMID: 34177884 PMCID: PMC8220072 DOI: 10.3389/fimmu.2021.629979] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 05/18/2021] [Indexed: 01/21/2023] Open
Abstract
Mammalian phagocytes can phagocytose (i.e. eat) other mammalian cells in the body if they display certain signals, and this phagocytosis plays fundamental roles in development, cell turnover, tissue homeostasis and disease prevention. To phagocytose the correct cells, phagocytes must discriminate which cells to eat using a 'phagocytic code' - a set of over 50 known phagocytic signals determining whether a cell is eaten or not - comprising find-me signals, eat-me signals, don't-eat-me signals and opsonins. Most opsonins require binding to eat-me signals - for example, the opsonins galectin-3, calreticulin and C1q bind asialoglycan eat-me signals on target cells - to induce phagocytosis. Some proteins act as 'self-opsonins', while others are 'negative opsonins' or 'phagocyte suppressants', inhibiting phagocytosis. We review known phagocytic signals here, both established and novel, and how they integrate to regulate phagocytosis of several mammalian targets - including excess cells in development, senescent and aged cells, infected cells, cancer cells, dead or dying cells, cell debris and neuronal synapses. Understanding the phagocytic code, and how it goes wrong, may enable novel therapies for multiple pathologies with too much or too little phagocytosis, such as: infectious disease, cancer, neurodegeneration, psychiatric disease, cardiovascular disease, ageing and auto-immune disease.
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Affiliation(s)
| | | | | | - Guy C. Brown
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
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28
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The Participation of Microglia in Neurogenesis: A Review. Brain Sci 2021; 11:brainsci11050658. [PMID: 34070012 PMCID: PMC8157831 DOI: 10.3390/brainsci11050658] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Revised: 05/12/2021] [Accepted: 05/15/2021] [Indexed: 01/17/2023] Open
Abstract
Adult neurogenesis was one of the most important discoveries of the last century, helping us to better understand brain function. Researchers recently discovered that microglia play an important role in this process. However, various questions remain concerning where, at what stage, and what types of microglia participate. In this review, we demonstrate that certain pools of microglia are determinant cells in different phases of the generation of new neurons. This sheds light on how cells cooperate in order to fine tune brain organization. It also provides us with a better understanding of distinct neuronal pathologies.
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29
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Mike JK, Ferriero DM. Efferocytosis Mediated Modulation of Injury after Neonatal Brain Hypoxia-Ischemia. Cells 2021; 10:1025. [PMID: 33925299 PMCID: PMC8146813 DOI: 10.3390/cells10051025] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/22/2021] [Accepted: 04/23/2021] [Indexed: 02/06/2023] Open
Abstract
Neonatal brain hypoxia-ischemia (HI) is a leading cause of morbidity and long-term disabilities in children. While we have made significant progress in describing HI mechanisms, the limited therapies currently offered for HI treatment in the clinical setting stress the importance of discovering new targetable pathways. Efferocytosis is an immunoregulatory and homeostatic process of clearance of apoptotic cells (AC) and cellular debris, best described in the brain during neurodevelopment. The therapeutic potential of stimulating defective efferocytosis has been recognized in neurodegenerative diseases. In this review, we will explore the involvement of efferocytosis after a stroke and HI as a promising target for new HI therapies.
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Affiliation(s)
- Jana Krystofova Mike
- Department of Pediatrics, University of California San Francisco, San Francisco, CA 94143, USA;
| | - Donna Marie Ferriero
- Department of Pediatrics, University of California San Francisco, San Francisco, CA 94143, USA;
- Department of Neurology Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA 94143, USA
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30
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Formation and integration of new neurons in the adult hippocampus. Nat Rev Neurosci 2021; 22:223-236. [PMID: 33633402 DOI: 10.1038/s41583-021-00433-z] [Citation(s) in RCA: 118] [Impact Index Per Article: 39.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/15/2021] [Indexed: 01/31/2023]
Abstract
Neural stem cells (NSCs) generate new neurons throughout life in the mammalian brain. Adult-born neurons shape brain function, and endogenous NSCs could potentially be harnessed for brain repair. In this Review, focused on hippocampal neurogenesis in rodents, we highlight recent advances in the field based on novel technologies (including single-cell RNA sequencing, intravital imaging and functional observation of newborn cells in behaving mice) and characterize the distinct developmental steps from stem cell activation to the integration of newborn neurons into pre-existing circuits. Further, we review current knowledge of how levels of neurogenesis are regulated, discuss findings regarding survival and maturation of adult-born cells and describe how newborn neurons affect brain function. The evidence arguing for (and against) lifelong neurogenesis in the human hippocampus is briefly summarized. Finally, we provide an outlook of what is needed to improve our understanding of the mechanisms and functional consequences of adult neurogenesis and how the field may move towards more translational relevance in the context of acute and chronic neural injury and stem cell-based brain repair.
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31
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Wasser B, Luchtman D, Löffel J, Robohm K, Birkner K, Stroh A, Vogelaar CF, Zipp F, Bittner S. CNS-localized myeloid cells capture living invading T cells during neuroinflammation. J Exp Med 2021; 217:151587. [PMID: 32219436 PMCID: PMC7971133 DOI: 10.1084/jem.20190812] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 09/20/2019] [Accepted: 01/17/2020] [Indexed: 11/28/2022] Open
Abstract
To study the role of myeloid cells in the central nervous system (CNS) in the pathogenesis of multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE), we used intravital microscopy, assessing local cellular interactions in vivo in EAE animals and ex vivo in organotypic hippocampal slice cultures. We discovered that myeloid cells actively engulf invading living Th17 lymphocytes, a process mediated by expression of activation-dependent lectin and its T cell–binding partner, N-acetyl-D-glucosamine (GlcNAc). Stable engulfment resulted in the death of the engulfed cells, and, remarkably, enhancement of GlcNAc exposure on T cells in the CNS ameliorated clinical EAE symptoms. These findings demonstrate the ability of myeloid cells to directly react to pathogenic T cell infiltration by engulfing living T cells. Amelioration of EAE via GlcNAc treatment suggests a novel first-defense pathway of myeloid cells as an initial response to CNS invasion and demonstrates that T cell engulfment by myeloid cells can be therapeutically exploited in vivo.
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Affiliation(s)
- Beatrice Wasser
- Department of Neurology, Focus Program Translational Neuroscience and Immunotherapy, Rhine Main Neuroscience Network, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Dirk Luchtman
- Department of Neurology, Focus Program Translational Neuroscience and Immunotherapy, Rhine Main Neuroscience Network, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Julian Löffel
- Department of Neurology, Focus Program Translational Neuroscience and Immunotherapy, Rhine Main Neuroscience Network, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Kerstin Robohm
- Department of Neurology, Focus Program Translational Neuroscience and Immunotherapy, Rhine Main Neuroscience Network, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Katharina Birkner
- Department of Neurology, Focus Program Translational Neuroscience and Immunotherapy, Rhine Main Neuroscience Network, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Albrecht Stroh
- Focus Program Translational Neurosciences, Institute for Microscopic Anatomy and Neurobiology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Christina Francisca Vogelaar
- Department of Neurology, Focus Program Translational Neuroscience and Immunotherapy, Rhine Main Neuroscience Network, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Frauke Zipp
- Department of Neurology, Focus Program Translational Neuroscience and Immunotherapy, Rhine Main Neuroscience Network, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Stefan Bittner
- Department of Neurology, Focus Program Translational Neuroscience and Immunotherapy, Rhine Main Neuroscience Network, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
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32
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Raiders S, Han T, Scott-Hewitt N, Kucenas S, Lew D, Logan MA, Singhvi A. Engulfed by Glia: Glial Pruning in Development, Function, and Injury across Species. J Neurosci 2021; 41:823-833. [PMID: 33468571 PMCID: PMC7880271 DOI: 10.1523/jneurosci.1660-20.2020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 10/20/2020] [Accepted: 10/26/2020] [Indexed: 02/07/2023] Open
Abstract
Phagocytic activity of glial cells is essential for proper nervous system sculpting, maintenance of circuitry, and long-term brain health. Glial engulfment of apoptotic cells and superfluous connections ensures that neuronal connections are appropriately refined, while clearance of damaged projections and neurotoxic proteins in the mature brain protects against inflammatory insults. Comparative work across species and cell types in recent years highlights the striking conservation of pathways that govern glial engulfment. Many signaling cascades used during developmental pruning are re-employed in the mature brain to "fine tune" synaptic architecture and even clear neuronal debris following traumatic events. Moreover, the neuron-glia signaling events required to trigger and perform phagocytic responses are impressively conserved between invertebrates and vertebrates. This review offers a compare-and-contrast portrayal of recent findings that underscore the value of investigating glial engulfment mechanisms in a wide range of species and contexts.
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Affiliation(s)
- Stephan Raiders
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109
- Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, Washington 98195
| | - Taeho Han
- UCSF Weill Institute for Neurosciences, University of California San Francisco, San Francisco, California 94158
| | - Nicole Scott-Hewitt
- F.M. Kirby Center for Neurobiology, Boston Children's Hospital, Boston, Massachusetts 02115
- Stanley Center for Psychiatric Research, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts 02142
| | - Sarah Kucenas
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904
| | - Deborah Lew
- Department of Biological Sciences, Fordham University, Bronx, New York 10458
| | - Mary A Logan
- Jungers Center, Department of Neurology, Oregon Health and Science University, Portland, Oregon 97239
| | - Aakanksha Singhvi
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109
- Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, Washington 98195
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33
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Sihombing MAEM, Safitri M, Zhou T, Wang L, McGinty S, Zhang HJ, Yin Y, Peng Q, Qiu J, Wang G. Unexpected Role of Nonimmune Cells: Amateur Phagocytes. DNA Cell Biol 2021; 40:157-171. [PMID: 33439750 DOI: 10.1089/dna.2020.5647] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Effective and efficient efferocytosis of dead cells and associated cellular debris are critical to tissue homeostasis and healing of injured tissues. This important task was previously thought to be restricted to professional phagocytes (PPs). However, accumulating evidence has revealed another type of phagocyte, the amateur phagocyte (AP), which can also participate in efferocytosis. APs are non-myeloid progenitor/nonimmune cells that include differentiated cells (e.g., epithelial cells, fibroblasts, and endothelial cells [ECs]) and stem cells (e.g., neuronal progenitor cells and mesenchymal cells) and can be found throughout the human body. Studies have shown that APs have two prominent roles: identifying and removing dead cells presumably before PPs reach the site of injury and assisting PPs in the removal of cell corpses and the resolution of inflamed tissue. With respect to the engulfment and degradation of dead cells, APs are slower and less efficient than PPs. However, APs are fundamental to preventing the spread of inflammation over a large area. In this review, we present the diversity and characteristics of healthy and non-neoplastic APs in mammals. We also propose a hypothetical mechanism of the efferocytosis of immunoglobulin G (IgG)-opsonized myelin debris by ECs (APs). Furthermore, the ingestion and clearance of dead cells can induce proinflammatory or anti-inflammatory cytokine production, endothelial activation, and cellular fate transition, which contribute to the progression of disease. An understanding of the role of APs is necessary to develop effective intervention strategies, including potential molecular targets for clinical diagnosis and drug development, for inflammation-related diseases.
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Affiliation(s)
- Maic Audo Eybi Mayer Sihombing
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing, China
| | - Maharani Safitri
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing, China
| | - Tian Zhou
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing, China
| | - Lu Wang
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing, China
| | - Sean McGinty
- Division of Biomedical Engineering, University of Glasgow, Glasgow, United Kingdom
| | - Hai-Jun Zhang
- Department of Vascular and Intervention, Tenth People's Hospital of Tongji University, Shanghai, China
| | - Yuxia Yin
- National United Engineering Laboratory for Biomedical Material Modification, Denzhou, China
| | - Qin Peng
- Institute of Systems and Physical Biology, Shenzen Bay Laboratory, Shenzhen, China
| | - Juhui Qiu
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing, China
| | - Guixue Wang
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing, China
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Lana D, Ugolini F, Giovannini MG. Space-Dependent Glia-Neuron Interplay in the Hippocampus of Transgenic Models of β-Amyloid Deposition. Int J Mol Sci 2020; 21:E9441. [PMID: 33322419 PMCID: PMC7763751 DOI: 10.3390/ijms21249441] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/03/2020] [Accepted: 12/09/2020] [Indexed: 12/14/2022] Open
Abstract
This review is focused on the description and discussion of the alterations of astrocytes and microglia interplay in models of Alzheimer's disease (AD). AD is an age-related neurodegenerative pathology with a slowly progressive and irreversible decline of cognitive functions. One of AD's histopathological hallmarks is the deposition of amyloid beta (Aβ) plaques in the brain. Long regarded as a non-specific, mere consequence of AD pathology, activation of microglia and astrocytes is now considered a key factor in both initiation and progression of the disease, and suppression of astrogliosis exacerbates neuropathology. Reactive astrocytes and microglia overexpress many cytokines, chemokines, and signaling molecules that activate or damage neighboring cells and their mutual interplay can result in virtuous/vicious cycles which differ in different brain regions. Heterogeneity of glia, either between or within a particular brain region, is likely to be relevant in healthy conditions and disease processes. Differential crosstalk between astrocytes and microglia in CA1 and CA3 areas of the hippocampus can be responsible for the differential sensitivity of the two areas to insults. Understanding the spatial differences and roles of glia will allow us to assess how these interactions can influence the state and progression of the disease, and will be critical for identifying therapeutic strategies.
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Affiliation(s)
- Daniele Lana
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Viale Pieraccini 6, 50139 Firenze, Italy;
| | - Filippo Ugolini
- Department of Health Sciences, Section of Anatomopathology, University of Florence, Viale Pieraccini 6, 50139 Firenze, Italy;
| | - Maria Grazia Giovannini
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Viale Pieraccini 6, 50139 Firenze, Italy;
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Coronas V, Terrié E, Déliot N, Arnault P, Constantin B. Calcium Channels in Adult Brain Neural Stem Cells and in Glioblastoma Stem Cells. Front Cell Neurosci 2020; 14:600018. [PMID: 33281564 PMCID: PMC7691577 DOI: 10.3389/fncel.2020.600018] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 10/06/2020] [Indexed: 12/12/2022] Open
Abstract
The brain of adult mammals, including humans, contains neural stem cells (NSCs) located within specific niches of which the ventricular-subventricular zone (V-SVZ) is the largest one. Under physiological conditions, NSCs proliferate, self-renew and produce new neurons and glial cells. Several recent studies established that oncogenic mutations in adult NSCs of the V-SVZ are responsible for the emergence of malignant primary brain tumors called glioblastoma. These aggressive tumors contain a small subpopulation of cells, the glioblastoma stem cells (GSCs), that are endowed with proliferative and self-renewal abilities like NSCs from which they may arise. GSCs are thus considered as the cells that initiate and sustain tumor growth and, because of their resistance to current treatments, provoke tumor relapse. A growing body of studies supports that Ca2+ signaling controls a variety of processes in NSCs and GSCs. Ca2+ is a ubiquitous second messenger whose fluctuations of its intracellular concentrations are handled by channels, pumps, exchangers, and Ca2+ binding proteins. The concerted action of the Ca2+ toolkit components encodes specific Ca2+ signals with defined spatio-temporal characteristics that determine the cellular responses. In this review, after a general overview of the adult brain NSCs and GSCs, we focus on the multiple roles of the Ca2+ toolkit in NSCs and discuss how GSCs hijack these mechanisms to promote tumor growth. Extensive knowledge of the role of the Ca2+ toolkit in the management of essential functions in healthy and pathological stem cells of the adult brain should help to identify promising targets for clinical applications.
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Affiliation(s)
- Valérie Coronas
- Laboratoire STIM, Université de Poitiers-CNRS ERL 7003, Poitiers, France
| | - Elodie Terrié
- Laboratoire STIM, Université de Poitiers-CNRS ERL 7003, Poitiers, France
| | - Nadine Déliot
- Laboratoire STIM, Université de Poitiers-CNRS ERL 7003, Poitiers, France
| | - Patricia Arnault
- Laboratoire STIM, Université de Poitiers-CNRS ERL 7003, Poitiers, France
| | - Bruno Constantin
- Laboratoire STIM, Université de Poitiers-CNRS ERL 7003, Poitiers, France
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Abstract
Cell death occurs when a pathogen invades a host organism or the organism is subjected to sterile injury. Thus, cell death is often closely associated with the induction of an immune response. Furthermore, cell death can occur as a consequence of the immune response and precedes the tissue renewal and repair responses that are initiated by innate immune cells during resolution of an immune response. Beyond immunity, cell death is required for development, morphogenesis and homeostasis. How can such a ubiquitous event as cell death trigger such a wide range of context-specific effector responses? Dying cells are sensed by innate immune cells using specialized receptors and phagocytosed through a process termed efferocytosis. Here, we outline a general principle whereby signals within the dead cell as well as the environment are integrated by specific efferocytes to define the appropriate effector response.
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Lana D, Ugolini F, Giovannini MG. An Overview on the Differential Interplay Among Neurons-Astrocytes-Microglia in CA1 and CA3 Hippocampus in Hypoxia/Ischemia. Front Cell Neurosci 2020; 14:585833. [PMID: 33262692 PMCID: PMC7686560 DOI: 10.3389/fncel.2020.585833] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 10/09/2020] [Indexed: 12/13/2022] Open
Abstract
Neurons have been long regarded as the basic functional cells of the brain, whereas astrocytes and microglia have been regarded only as elements of support. However, proper intercommunication among neurons-astrocytes-microglia is of fundamental importance for the functional organization of the brain. Perturbation in the regulation of brain energy metabolism not only in neurons but also in astrocytes and microglia may be one of the pathophysiological mechanisms of neurodegeneration, especially in hypoxia/ischemia. Glial activation has long been considered detrimental for survival of neurons, but recently it appears that glial responses to an insult are not equal but vary in different brain areas. In this review, we first take into consideration the modifications of the vascular unit of the glymphatic system and glial metabolism in hypoxic conditions. Using the method of triple-labeling fluorescent immunohistochemistry coupled with confocal microscopy (TIC), we recently studied the interplay among neurons, astrocytes, and microglia in chronic brain hypoperfusion. We evaluated the quantitative and morpho-functional alterations of the neuron-astrocyte-microglia triads comparing the hippocampal CA1 area, more vulnerable to ischemia, to the CA3 area, less vulnerable. In these contiguous and interconnected areas, in the same experimental hypoxic conditions, astrocytes and microglia show differential, finely regulated, region-specific reactivities. In both areas, astrocytes and microglia form triad clusters with apoptotic, degenerating neurons. In the neuron-astrocyte-microglia triads, the cell body of a damaged neuron is infiltrated and bisected by branches of astrocyte that create a microscar around it while a microglial cell phagocytoses the damaged neuron. These coordinated actions are consistent with the scavenging and protective activities of microglia. In hypoxia, the neuron-astrocyte-microglia triads are more numerous in CA3 than in CA1, further indicating their protective effects. These data, taken from contiguous and interconnected hippocampal areas, demonstrate that glial response to the same hypoxic insult is not equal but varies significantly. Understanding the differences of glial reactivity is of great interest to explain the differential susceptibility of hippocampal areas to hypoxia/ischemia. Further studies may evidence the differential reactivity of glia in different brain areas, explaining the higher or lower sensitivity of these areas to different insults and whether glia may represent a target for future therapeutic interventions.
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Affiliation(s)
- Daniele Lana
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Florence, Italy
| | - Filippo Ugolini
- Department of Health Sciences, Section of Anatomopathology, University of Florence, Florence, Italy
| | - Maria G Giovannini
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Florence, Italy
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Neuroepithelial cell competition triggers loss of cellular juvenescence. Sci Rep 2020; 10:18044. [PMID: 33093561 PMCID: PMC7582913 DOI: 10.1038/s41598-020-74874-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 10/07/2020] [Indexed: 12/02/2022] Open
Abstract
Cell competition is a cell–cell interaction mechanism which maintains tissue homeostasis through selective elimination of unfit cells. During early brain development, cells are eliminated through apoptosis. How cells are selected to undergo elimination remains unclear. Here we aimed to identify a role for cell competition in the elimination of suboptimal cells using an in vitro neuroepithelial model. Cell competition was observed when neural progenitor HypoE-N1 cells expressing RASV12 were surrounded by normal cells in the co-culture. The elimination through apoptosis was observed by cellular changes of RASV12 cells with rounding/fragmented morphology, by SYTOX blue-positivity, and by expression of apoptotic markers active caspase-3 and cleaved PARP. In this model, expression of juvenility-associated genes Srsf7 and Ezh2 were suppressed under cell-competitive conditions. Srsf7 depletion led to loss of cellular juvenescence characterized by suppression of Ezh2, cell growth impairment and enhancement of senescence-associated proteins. The cell bodies of eliminated cells were engulfed by the surrounding cells through phagocytosis. Our data indicates that neuroepithelial cell competition may have an important role for maintaining homeostasis in the neuroepithelium by eliminating suboptimal cells through loss of cellular juvenescence.
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Araki T, Ikegaya Y, Koyama R. The effects of microglia‐ and astrocyte‐derived factors on neurogenesis in health and disease. Eur J Neurosci 2020; 54:5880-5901. [PMID: 32920880 PMCID: PMC8451940 DOI: 10.1111/ejn.14969] [Citation(s) in RCA: 82] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 09/01/2020] [Accepted: 09/02/2020] [Indexed: 12/20/2022]
Abstract
Hippocampal neurogenesis continues throughout life and has been suggested to play an essential role in maintaining spatial cognitive function under physiological conditions. An increasing amount of evidence has indicated that adult neurogenesis is tightly controlled by environmental conditions in the neurogenic niche, which consists of multiple types of cells including microglia and astrocytes. Microglia maintain the environment of neurogenic niche through their phagocytic capacity and interaction with neurons via fractalkine‐CX3CR1 signaling. In addition, microglia release growth factors such as brain‐derived neurotrophic factor (BDNF) and cytokines such as tumor necrosis factor (TNF)‐α to support the development of adult born neurons. Astrocytes also manipulate neurogenesis by releasing various soluble factors including adenosine triphosphate and lactate. Whereas, under pathological conditions such as Alzheimer's disease, depression, and epilepsy, microglia and astrocytes play a leading role in inflammation and are involved in attenuating the normal process of neurogenesis. The modulation of glial functions on neurogenesis in these brain diseases are attracting attention as a new therapeutic target. This review describes how these glial cells play a role in adult hippocampal neurogenesis in both health and disease, especially focusing glia‐derived factors.
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Affiliation(s)
- Tasuku Araki
- Laboratory of Chemical Pharmacology Graduate School of Pharmaceutical Sciences The University of Tokyo Tokyo Japan
| | - Yuji Ikegaya
- Laboratory of Chemical Pharmacology Graduate School of Pharmaceutical Sciences The University of Tokyo Tokyo Japan
- Center for Information and Neural Networks Suita City Osaka Japan
| | - Ryuta Koyama
- Laboratory of Chemical Pharmacology Graduate School of Pharmaceutical Sciences The University of Tokyo Tokyo Japan
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40
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Lehotzky D, Sipahi R, Zupanc GKH. Cellular automata modeling suggests symmetric stem-cell division, cell death, and cell drift as key mechanisms driving adult spinal cord growth in teleost fish. J Theor Biol 2020; 509:110474. [PMID: 32918922 DOI: 10.1016/j.jtbi.2020.110474] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 08/10/2020] [Accepted: 08/31/2020] [Indexed: 12/13/2022]
Abstract
Adult neurogenesis - the generation of neurons during adulthood - is intensively studied, yet little is known about its consequences at the tissue level. In the teleost fish Apteronotus leptorhynchus, morphometric analysis has revealed that the total number of cells in the spinal cord increases continuously throughout adulthood, driven by the activity of neurogenic stem/progenitor cells in both the ependymal layer at the central canal and in the radially located parenchyma. This net increase in cell numbers demonstrates cellular addition, as opposed to cellular turnover which appears to be the common outcome of adult neurogenesis in mammals. Grounded on a comprehensive set of quantitative data generated through high-resolution mapping of stem cells and their progeny, we constructed a cellular automata model of the stem-cell-driven growth of the spinal cord. Simulations based on this model suggest that three cellular mechanisms play a critical role for promoting sustained tissue growth and acquisition of correct form of the spinal cord, including the development of the ependymal layer and the parenchyma: the number of symmetric stem-cell divisions versus asymmetric divisions; the probability of the progeny of progenitor cells to undergo cell death; and the radial drifting of cells.
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Affiliation(s)
- Dávid Lehotzky
- Laboratory of Neurobiology, Department of Biology, Northeastern University, Boston, MA, United States.
| | - Rifat Sipahi
- Complex Dynamic Systems and Control Laboratory, Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA, United States.
| | - Günther K H Zupanc
- Laboratory of Neurobiology, Department of Biology, Northeastern University, Boston, MA, United States.
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41
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Abstract
Adult neurogenesis is a process that generates new and functional neurons from neural stem cells (NSCs) in a specialized neurogenic niche throughout life. Misregulated neurogenesis is detrimental to normal brain functions. To ensure proper neurogenesis, the niche cells must respond to extrinsic cues while fulfilling the intrinsic requirements of the neurogenic program and adapting their roles accordingly to influence NSC behavior. Understanding how the neurogenic niche executes its functions may guide strategies to maintain its integrative process and provide a permissive milieu for neurogenesis. In this review, we summarize the recent discoveries of interactive regulation of NSCs and neurogenesis by neurogenic niche and its implications in functional integrity of adult brain and neurological disorders.
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Affiliation(s)
- Yue Li
- State Key Laboratory of Component-Based Chinese Medicine, Ministry of Education Key Laboratory of Pharmacology of Traditional Chinese Medicine Formulae, Institute of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Weixiang Guo
- State Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.,Graduate School, University of Chinese Academy of Sciences, Beijing, China
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42
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Borsini A, Stangl D, Jeffries AR, Pariante CM, Thuret S. The role of omega-3 fatty acids in preventing glucocorticoid-induced reduction in human hippocampal neurogenesis and increase in apoptosis. Transl Psychiatry 2020; 10:219. [PMID: 32636362 PMCID: PMC7341841 DOI: 10.1038/s41398-020-00908-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 06/15/2020] [Accepted: 06/23/2020] [Indexed: 12/21/2022] Open
Abstract
Glucocorticoids have been suggested to be involved in several neuropsychiatric disorders, including depression. One of the possible mechanisms through which glucocorticoids contribute to the development of the depressive symptomatology is via regulation of distinct neurogenic mechanisms in the brain. A preventive or protective approach for these patients might be the use of omega-3 polyunsaturated fatty acids (n-3 PUFAs), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are known for they neuroprotective properties. We used the human hippocampal progenitor cell line HPC0A07/03C and pre-treated cells with either EPA or DHA, followed by treatment with the glucocorticoid cortisol either alone, or in co-treatment with the same n-3 PUFA during subsequent 3 days of proliferation and 7 days of differentiation. During proliferation, both EPA and DHA were able to prevent cortisol-induced reduction in proliferation and increase in apoptosis, when used in pre-treatment, and both pre- and co-treatment. During differentiation, EPA was able to prevent cortisol-induced reduction in neurogenesis and increase in apoptosis, when used in pre-treatment, and both pre- and co-treatment only during the proliferation stage; however, DHA required continuous treatment also during the differentiation stage to prevent cortisol-induced reduction in neurogenesis. Using transcriptomic analyses, we showed that both EPA and DHA regulated pathways involved in oxidative stress and immune response [e.g., nuclear factor (erythroid-derived 2)-like 2 (Nrf2), Signal transducer and activator of transcription 3 (STAT3), Interferon (IFN) and Interleukin (IL)-1 signaling], whereas DHA also regulated pathways involved in cell development and neuronal formation [e.g., cAMP-response element binding protein (CREB) signaling]. We provide the first evidence for treatment with both EPA and DHA to prevent cortisol-induced reduction in human hippocampal neurogenesis, and identify novel molecular mechanisms underlying these effects.
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Affiliation(s)
- Alessandra Borsini
- Section of Stress, Psychiatry and Immunology & Perinatal Psychiatry, King's College London, Institute of Psychiatry, Psychology & Neuroscience, Department of Psychological Medicine, London, UK.
- King's College London, Institute of Psychiatry, Psychology & Neuroscience, Department of Basic and Clinical Neuroscience, London, UK.
| | - Doris Stangl
- King's College London, Institute of Psychiatry, Psychology & Neuroscience, Department of Basic and Clinical Neuroscience, London, UK
| | | | - Carmine M Pariante
- Section of Stress, Psychiatry and Immunology & Perinatal Psychiatry, King's College London, Institute of Psychiatry, Psychology & Neuroscience, Department of Psychological Medicine, London, UK
| | - Sandrine Thuret
- King's College London, Institute of Psychiatry, Psychology & Neuroscience, Department of Basic and Clinical Neuroscience, London, UK.
- Department of Neurology, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.
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43
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Li XW, Li XX, Liu QS, Cheng Y. Blood and Cerebrospinal Fluid Autoantibody to Aβ Levels in Patients with Alzheimer’s Disease: a Meta-Analysis Study. J Mol Neurosci 2020; 70:1208-1215. [DOI: 10.1007/s12031-020-01528-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 03/02/2020] [Indexed: 01/01/2023]
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44
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Yoon H, Choi SI, Kim EK. Uptake of cell debris and enhanced expression of inflammatory factors in response to dead cells in corneal fibroblast cells. Exp Eye Res 2020; 194:108017. [PMID: 32217186 DOI: 10.1016/j.exer.2020.108017] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 02/27/2020] [Accepted: 03/17/2020] [Indexed: 12/17/2022]
Abstract
Keratocytes synthesize stromal proteins and participate in wound healing through successive differentiation into corneal fibroblasts and myofibroblasts. Cultured keratocytes or corneal fibroblasts are also known as non-professional phagocytes and innate immune cells. However, whether the corneal fibroblasts phagocytize their dead cells and whether the associated innate immunity is enhanced remains unknown. We initially characterized immortalized corneal fibroblast cells with the expression of specific genes. The corneal fibroblasts strongly expressed extracellular matrix molecules (FN and COL1A1) and low or medium levels of macrophage markers (CD14, CD68, and CD36), inflammatory cytokines (IL1A, IL1B, and IL6), and chemokines (IL8 and CCL2), but not CD11b, suggesting that corneal fibroblasts are macrophage-like fibroblasts. We confirmed the phagocytic activity of the corneal fibroblasts with fluorescent dye labeled-dead E. coli and S. aureus bacteria using confocal microscopy and flow cytometry. To test corneal fibroblast phagocytosis of apoptotic and necrotic cells we co-cultured corneal fibroblasts with fluorescent dye labeled-apoptotic and -necrotic cells and analyzed their uptake using fluorescence and confocal microscopy. We observed that corneal fibroblasts can engulf digested or processed cellular debris and entire dead cells. Co-cultured dying and dead cells strongly enhanced the expression of cytokine (IL1A, IL1B, and IL6), chemokine (CCL2, CCL5, CCL20, IL8, and CXCL10), and MMP (MMP1, MMP3, and MMP9) genes through the NF-κB signaling pathway. Our findings suggest that dying and dead cells stimulate corneal fibroblasts to further induce inflammatory factors and that corneal fibroblasts contribute to the clearing of cell debris as non-professional phagocytes.
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Affiliation(s)
- Heejei Yoon
- Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, South Korea
| | - Seung-Il Choi
- Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, South Korea
| | - Eung Kweon Kim
- Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, South Korea; Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, South Korea.
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45
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Mikdache A, Fontenas L, Albadri S, Revenu C, Loisel-Duwattez J, Lesport E, Degerny C, Del Bene F, Tawk M. Elmo1 function, linked to Rac1 activity, regulates peripheral neuronal numbers and myelination in zebrafish. Cell Mol Life Sci 2020; 77:161-177. [PMID: 31161284 PMCID: PMC11104998 DOI: 10.1007/s00018-019-03167-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 05/28/2019] [Accepted: 05/28/2019] [Indexed: 12/20/2022]
Abstract
Peripheral nervous system development involves a tight coordination of neuronal birth and death and a substantial remodelling of the myelinating glia cytoskeleton to achieve myelin wrapping of its projecting axons. However, how these processes are coordinated through time is still not understood. We have identified engulfment and cell motility 1, Elmo1, as a novel component that regulates (i) neuronal numbers within the Posterior Lateral Line ganglion and (ii) radial sorting of axons by Schwann cells (SC) and myelination in the PLL system in zebrafish. Our results show that neuronal and myelination defects observed in elmo1 mutant are rescued through small GTPase Rac1 activation. Inhibiting macrophage development leads to a decrease in neuronal numbers, while peripheral myelination is intact. However, elmo1 mutants do not show defective macrophage activity, suggesting a role for Elmo1 in PLLg neuronal development and SC myelination independent of macrophages. Forcing early Elmo1 and Rac1 expression specifically within SCs rescues elmo1-/- myelination defects, highlighting an autonomous role for Elmo1 and Rac1 in radial sorting of axons by SCs and myelination. This uncovers a previously unknown function of Elmo1 that regulates fundamental aspects of PNS development.
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Affiliation(s)
- Aya Mikdache
- U1195, Inserm, University Paris Sud, University Paris-Saclay, 94276, Le Kremlin Bicêtre, France
| | - Laura Fontenas
- U1195, Inserm, University Paris Sud, University Paris-Saclay, 94276, Le Kremlin Bicêtre, France
- Department of Biology, University of Virginia, Charlottesville, VA, 22904-4328, USA
| | - Shahad Albadri
- Institut Curie, PSL Research University, 75005, Paris, France
| | - Celine Revenu
- Institut Curie, PSL Research University, 75005, Paris, France
| | - Julien Loisel-Duwattez
- U1195, Inserm, University Paris Sud, University Paris-Saclay, 94276, Le Kremlin Bicêtre, France
| | - Emilie Lesport
- U1195, Inserm, University Paris Sud, University Paris-Saclay, 94276, Le Kremlin Bicêtre, France
| | - Cindy Degerny
- U1195, Inserm, University Paris Sud, University Paris-Saclay, 94276, Le Kremlin Bicêtre, France
| | | | - Marcel Tawk
- U1195, Inserm, University Paris Sud, University Paris-Saclay, 94276, Le Kremlin Bicêtre, France.
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46
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Bacigaluppi M, Sferruzza G, Butti E, Ottoboni L, Martino G. Endogenous neural precursor cells in health and disease. Brain Res 2019; 1730:146619. [PMID: 31874148 DOI: 10.1016/j.brainres.2019.146619] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 11/25/2019] [Accepted: 12/19/2019] [Indexed: 12/15/2022]
Abstract
Neurogenesis persists in the adult brain of mammals in the subventricular zone (SVZ) of the lateral ventricles and in the subgranular zone (SGZ) of the dentate gyrus (DG). The complex interactions between intrinsic and extrinsic signals provided by cells in the niche but also from distant sources regulate the fate of neural stem/progenitor cells (NPCs) in these sites. This fine regulation is perturbed in aging and in pathological conditions leading to a different NPC behavior, tailored to the specific physio-pathological features. Indeed, NPCs exert in physiological and pathological conditions important neurogenic and non-neurogenic regulatory functions and participate in maintaining and protecting brain tissue homeostasis. In this review, we discuss intrinsic and extrinsic signals that regulate NPC activation and NPC functional role in various homeostatic and non-homeostatic conditions.
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Affiliation(s)
- Marco Bacigaluppi
- Neuroimmunology Unit and Department of Neurology, Institute of Experimental Neurology, San Raffaele Hospital and Università Vita- Salute San Raffaele, Via Olgettina 60, 20132 Milano, Italy.
| | - Giacomo Sferruzza
- Neuroimmunology Unit and Department of Neurology, Institute of Experimental Neurology, San Raffaele Hospital and Università Vita- Salute San Raffaele, Via Olgettina 60, 20132 Milano, Italy
| | - Erica Butti
- Neuroimmunology Unit and Department of Neurology, Institute of Experimental Neurology, San Raffaele Hospital and Università Vita- Salute San Raffaele, Via Olgettina 60, 20132 Milano, Italy
| | - Linda Ottoboni
- Neuroimmunology Unit and Department of Neurology, Institute of Experimental Neurology, San Raffaele Hospital and Università Vita- Salute San Raffaele, Via Olgettina 60, 20132 Milano, Italy
| | - Gianvito Martino
- Neuroimmunology Unit and Department of Neurology, Institute of Experimental Neurology, San Raffaele Hospital and Università Vita- Salute San Raffaele, Via Olgettina 60, 20132 Milano, Italy
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47
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Living on the Edge: Efferocytosis at the Interface of Homeostasis and Pathology. Immunity 2019; 50:1149-1162. [PMID: 31117011 DOI: 10.1016/j.immuni.2019.04.018] [Citation(s) in RCA: 210] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Revised: 04/13/2019] [Accepted: 04/29/2019] [Indexed: 01/23/2023]
Abstract
Nearly every tissue in the body undergoes routine turnover of cells as part of normal healthy living. The majority of these cells undergoing turnover die via apoptosis, and then are rapidly removed by phagocytes by the process of efferocytosis that is anti-inflammatory. However, a number of pathologies have recently been linked to defective clearance of apoptotic cells. Perturbed clearance arises for many reasons, including overwhelming of the clearance machinery, disruptions at different stages of efferocytosis, and responses of phagocytes during efferocytosis, all of which can alter the homeostatic tissue environment. This review covers linkages of molecules involved in the different phases of efferocytosis to disease pathologies that can arise due to their loss or altered function.
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48
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Zhu Y, Crowley SC, Latimer AJ, Lewis GM, Nash R, Kucenas S. Migratory Neural Crest Cells Phagocytose Dead Cells in the Developing Nervous System. Cell 2019; 179:74-89.e10. [PMID: 31495570 DOI: 10.1016/j.cell.2019.08.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Revised: 07/16/2019] [Accepted: 08/01/2019] [Indexed: 12/20/2022]
Abstract
During neural tube closure and spinal cord development, many cells die in both the central and peripheral nervous systems (CNS and PNS, respectively). However, myeloid-derived professional phagocytes have not yet colonized the trunk region during early neurogenesis. How apoptotic cells are removed from this region during these stages remains largely unknown. Using live imaging in zebrafish, we demonstrate that neural crest cells (NCCs) respond rapidly to dying cells and phagocytose cellular debris around the neural tube. Additionally, NCCs have the ability to enter the CNS through motor exit point transition zones and clear debris in the spinal cord. Surprisingly, NCCs phagocytosis mechanistically resembles macrophage phagocytosis and their recruitment toward cellular debris is mediated by interleukin-1β. Taken together, our results reveal a role for NCCs in phagocytosis of debris in the developing nervous system before the presence of professional phagocytes.
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Affiliation(s)
- Yunlu Zhu
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Samantha C Crowley
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Andrew J Latimer
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Gwendolyn M Lewis
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Rebecca Nash
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Sarah Kucenas
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA.
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49
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Siebert S, Farrell JA, Cazet JF, Abeykoon Y, Primack AS, Schnitzler CE, Juliano CE. Stem cell differentiation trajectories in Hydra resolved at single-cell resolution. Science 2019; 365:eaav9314. [PMID: 31346039 PMCID: PMC7104783 DOI: 10.1126/science.aav9314] [Citation(s) in RCA: 177] [Impact Index Per Article: 35.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 06/11/2019] [Indexed: 12/31/2022]
Abstract
The adult Hydra polyp continually renews all of its cells using three separate stem cell populations, but the genetic pathways enabling this homeostatic tissue maintenance are not well understood. We sequenced 24,985 Hydra single-cell transcriptomes and identified the molecular signatures of a broad spectrum of cell states, from stem cells to terminally differentiated cells. We constructed differentiation trajectories for each cell lineage and identified gene modules and putative regulators expressed along these trajectories, thus creating a comprehensive molecular map of all developmental lineages in the adult animal. In addition, we built a gene expression map of the Hydra nervous system. Our work constitutes a resource for addressing questions regarding the evolution of metazoan developmental processes and nervous system function.
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Affiliation(s)
- Stefan Siebert
- Department of Molecular and Cellular Biology, University of California, Davis, CA, USA.
| | - Jeffrey A Farrell
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
| | - Jack F Cazet
- Department of Molecular and Cellular Biology, University of California, Davis, CA, USA
| | - Yashodara Abeykoon
- Department of Molecular and Cellular Biology, University of California, Davis, CA, USA
| | - Abby S Primack
- Department of Molecular and Cellular Biology, University of California, Davis, CA, USA
| | - Christine E Schnitzler
- Whitney Laboratory for Marine Bioscience and Department of Biology, University of Florida, St. Augustine, FL, USA
| | - Celina E Juliano
- Department of Molecular and Cellular Biology, University of California, Davis, CA, USA.
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A balanced evaluation of the evidence for adult neurogenesis in humans: implication for neuropsychiatric disorders. Brain Struct Funct 2019; 224:2281-2295. [PMID: 31278571 DOI: 10.1007/s00429-019-01917-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Accepted: 06/25/2019] [Indexed: 12/17/2022]
Abstract
There is a widespread belief that neurogenesis exists in adult human brain, especially in the dentate gyrus, and it is to be maintained and, if possible, augmented with different stimuli including exercise and certain drugs. Here, we examine the evidence for adult human neurogenesis and note important limitations of the methodologies used to study it. A balanced review of the literature and evaluation of the data indicate that adult neurogenesis in human brain is improbable. In fact, in several high-quality recent studies in adult human brain, unlike in adult brains of other species, neurogenesis was not detectable. These findings suggest that the human brain requires a permanent set of neurons to maintain acquired knowledge for decades, which is essential for complex high cognitive functions unique to humans. Thus, stimulation and/or injection of neural stem cells into human brains may not only disrupt brain homeostatic systems, but also disturb normal neuronal circuits. We propose that the focus of research should be the preservation of brain neurons by prevention of damage, not replacement.
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