1
|
Corvelyn M, De Beukelaer N, Duelen R, Deschrevel J, Van Campenhout A, Prinsen S, Gayan-Ramirez G, Maes K, Weide G, Desloovere K, Sampaolesi M, Costamagna D. Muscle Microbiopsy to Delineate Stem Cell Involvement in Young Patients: A Novel Approach for Children With Cerebral Palsy. Front Physiol 2020; 11:945. [PMID: 32848872 PMCID: PMC7424076 DOI: 10.3389/fphys.2020.00945] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 07/14/2020] [Indexed: 12/18/2022] Open
Abstract
Cerebral palsy (CP), the single largest cause of childhood physical disability, is characterized firstly by a lesion in the immature brain, and secondly by musculoskeletal problems that progress with age. Previous research reported altered muscle properties, such as reduced volume and satellite cell (SC) numbers and hypertrophic extracellular matrix compared to typically developing (TD) children (>10 years). Unfortunately, data on younger CP patients are scarce and studies on SCs and other muscle stem cells in CP are insufficient or lacking. Therefore, it remains difficult to understand the early onset and trajectory of altered muscle properties in growing CP children. Because muscle stem cells are responsible for postnatal growth, repair and remodeling, multiple adult stem cell populations from young CP children could play a role in altered muscle development. To this end, new methods for studying muscle samples of young children, valid to delineate the features and to elucidate the regenerative potential of muscle tissue, are necessary. Using minimal invasive muscle microbiopsy, which was applied in young subjects under general anaesthesia for the first time, we aimed to isolate and characterize muscle stem cell-derived progenitors of TD children and patients with CP. Data of 15 CP patients, 3–9 years old, and 5 aged-matched TD children were reported. The muscle microbiopsy technique was tolerated well in all participants. Through the explant technique, we provided muscle stem cell-derived progenitors from the Medial Gastrocnemius. Via fluorescent activated cell sorting, using surface markers CD56, ALP, and PDGFRa, we obtained SC-derived progenitors, mesoangioblasts and fibro-adipogenic progenitors, respectively. Adipogenic, skeletal, and smooth muscle differentiation assays confirmed the cell identity and ability to give rise to different cell types after appropriate stimuli. Myogenic differentiation in CP SC-derived progenitors showed enhanced fusion index and altered myotube formation based on MYOSIN HEAVY CHAIN expression, as well as disorganization of nuclear spreading, which were not observed in TD myotubes. In conclusion, the microbiopsy technique allows more focused muscle research in young CP patients. Current results show altered differentiation abilities of muscle stem cell-derived progenitors and support the hypothesis of their involvement in CP-altered muscle growth.
Collapse
Affiliation(s)
- Marlies Corvelyn
- Stem Cell Biology and Embryology, Department of Development and Regeneration, KU Leuven, Leuven, Belgium
| | - Nathalie De Beukelaer
- Neurorehabilitation Group, Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium
| | - Robin Duelen
- Stem Cell Biology and Embryology, Department of Development and Regeneration, KU Leuven, Leuven, Belgium
| | - Jorieke Deschrevel
- Laboratory of Respiratory Disease and Thoracic Surgery, Department of Chronic Diseases and Metabolism, KU Leuven, Leuven, Belgium
| | - Anja Van Campenhout
- Pediatric Orthopedics, Department of Development and Regeneration, KU Leuven, Leuven, Belgium
| | - Sandra Prinsen
- Pediatric Orthopedics, Department of Development and Regeneration, KU Leuven, Leuven, Belgium
| | - Ghislaine Gayan-Ramirez
- Laboratory of Respiratory Disease and Thoracic Surgery, Department of Chronic Diseases and Metabolism, KU Leuven, Leuven, Belgium
| | - Karen Maes
- Laboratory of Respiratory Disease and Thoracic Surgery, Department of Chronic Diseases and Metabolism, KU Leuven, Leuven, Belgium
| | - Guido Weide
- Neurorehabilitation Group, Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium.,Laboratory of Respiratory Disease and Thoracic Surgery, Department of Chronic Diseases and Metabolism, KU Leuven, Leuven, Belgium
| | - Kaat Desloovere
- Neurorehabilitation Group, Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium
| | - Maurilio Sampaolesi
- Stem Cell Biology and Embryology, Department of Development and Regeneration, KU Leuven, Leuven, Belgium
| | - Domiziana Costamagna
- Stem Cell Biology and Embryology, Department of Development and Regeneration, KU Leuven, Leuven, Belgium.,Neurorehabilitation Group, Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium
| |
Collapse
|
2
|
Mavoungou LO, Neuenschwander S, Pham U, Iyer PS, Mermod N. Characterization of mesoangioblast cell fate and improved promyogenic potential of a satellite cell-like subpopulation upon transplantation in dystrophic murine muscles. Stem Cell Res 2019; 41:101619. [PMID: 31683098 DOI: 10.1016/j.scr.2019.101619] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 09/20/2019] [Accepted: 10/11/2019] [Indexed: 12/13/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a lethal muscle-wasting disease caused by the lack of dystrophin in muscle fibers that is currently without curative treatment. Mesoangioblasts (MABs) are multipotent progenitor cells that can differentiate to a myogenic lineage and that can be used to express Dystrophin upon transplantation into muscles, in autologous gene therapy approaches. However, their fate in the muscle environment remains poorly characterized. Here, we investigated the differentiation fate of MABs following their transplantation in DMD murine muscles using a mass cytometry strategy. This allowed the identification and isolation of a fraction of MAB-derived cells presenting common properties with satellite muscle stem cells. This analysis also indicated that most cells did not undergo a myogenic differentiation path once in the muscle environment, limiting their capacity to restore dystrophin expression in transplanted muscles. We therefore assessed whether MAB treatment with cytokines and growth factors prior to engraftment may improve their myogenic fate. We identified a combination of such signals that ameliorates MABs capacity to undergo myogenic differentiation in vivo and to restore dystrophin expression upon engraftment in myopathic murine muscles.
Collapse
Affiliation(s)
- Lionel O Mavoungou
- Institute of Biotechnology and Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | | | - Uyen Pham
- Grand Valley State University, MI, USA
| | - Pavithra S Iyer
- Institute of Biotechnology and Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland; Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zürich, Switzerland
| | - Nicolas Mermod
- Institute of Biotechnology and Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland.
| |
Collapse
|
3
|
De Santa F, Vitiello L, Torcinaro A, Ferraro E. The Role of Metabolic Remodeling in Macrophage Polarization and Its Effect on Skeletal Muscle Regeneration. Antioxid Redox Signal 2019; 30:1553-1598. [PMID: 30070144 DOI: 10.1089/ars.2017.7420] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Significance: Macrophages are crucial for tissue homeostasis. Based on their activation, they might display classical/M1 or alternative/M2 phenotypes. M1 macrophages produce pro-inflammatory cytokines, reactive oxygen species (ROS), and nitric oxide (NO). M2 macrophages upregulate arginase-1 and reduce NO and ROS levels; they also release anti-inflammatory cytokines, growth factors, and polyamines, thus promoting angiogenesis and tissue healing. Moreover, M1 and M2 display key metabolic differences; M1 polarization is characterized by an enhancement in glycolysis and in the pentose phosphate pathway (PPP) along with a decreased oxidative phosphorylation (OxPhos), whereas M2 are characterized by an efficient OxPhos and reduced PPP. Recent Advances: The glutamine-related metabolism has been discovered as crucial for M2 polarization. Vice versa, flux discontinuities in the Krebs cycle are considered additional M1 features; they lead to increased levels of immunoresponsive gene 1 and itaconic acid, to isocitrate dehydrogenase 1-downregulation and to succinate, citrate, and isocitrate over-expression. Critical Issues: A macrophage classification problem, particularly in vivo, originating from a gap in the knowledge of the several intermediate polarization statuses between the M1 and M2 extremes, characterizes this field. Moreover, the detailed features of metabolic reprogramming crucial for macrophage polarization are largely unknown; in particular, the role of β-oxidation is highly controversial. Future Directions: Manipulating the metabolism to redirect macrophage polarization might be useful in various pathologies, including an efficient skeletal muscle regeneration. Unraveling the complexity pertaining to metabolic signatures that are specific for the different macrophage subsets is crucial for identifying new compounds that are able to trigger macrophage polarization and that might be used for therapeutical purposes.
Collapse
Affiliation(s)
- Francesca De Santa
- Institute of Cell Biology and Neurobiology (IBCN), National Research Council (CNR), Rome, Italy
| | - Laura Vitiello
- Laboratory of Pathophysiology of Cachexia and Metabolism of Skeletal Muscle, IRCCS San Raffaele Pisana, Rome, Italy
| | - Alessio Torcinaro
- Institute of Cell Biology and Neurobiology (IBCN), National Research Council (CNR), Rome, Italy.,Department of Biology and Biotechnology "Charles Darwin," Sapienza University, Rome, Italy
| | - Elisabetta Ferraro
- Laboratory of Pathophysiology of Cachexia and Metabolism of Skeletal Muscle, IRCCS San Raffaele Pisana, Rome, Italy
| |
Collapse
|
4
|
Manfredi AA, Ramirez GA, Rovere-Querini P, Maugeri N. The Neutrophil's Choice: Phagocytose vs Make Neutrophil Extracellular Traps. Front Immunol 2018. [PMID: 29515586 PMCID: PMC5826238 DOI: 10.3389/fimmu.2018.00288] [Citation(s) in RCA: 145] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Neutrophils recognize particulate substrates of microbial or endogenous origin and react by sequestering the cargo via phagocytosis or by releasing neutrophil extracellular traps (NETs) outside the cell, thus modifying and alerting the environment and bystander leukocytes. The signals that determine the choice between phagocytosis and the generation of NETs are still poorly characterized. Neutrophils that had phagocytosed bulky particulate substrates, such as apoptotic cells and activated platelets, appear to be “poised” in an unresponsive state. Environmental conditions, the metabolic, adhesive and activation state of the phagocyte, and the size of and signals associated with the tethered phagocytic cargo influence the choice of the neutrophils, prompting either phagocytic clearance or the generation of NETs. The choice is dichotomic and apparently irreversible. Defects in phagocytosis may foster the intravascular generation of NETs, thus promoting vascular inflammation and morbidities associated with diseases characterized by defective phagocytic clearance, such as systemic lupus erythematosus. There is a strong potential for novel treatments based on new knowledge of the events determining the inflammatory and pro-thrombotic function of inflammatory leukocytes.
Collapse
Affiliation(s)
- Angelo A Manfredi
- Università Vita-Salute San Raffaele, Milano, Italy.,Division of Immunology, Transplantation and Infectious Diseases, IRCCS Ospedale San Raffaele, Milano, Italy
| | - Giuseppe A Ramirez
- Università Vita-Salute San Raffaele, Milano, Italy.,Division of Immunology, Transplantation and Infectious Diseases, IRCCS Ospedale San Raffaele, Milano, Italy
| | - Patrizia Rovere-Querini
- Università Vita-Salute San Raffaele, Milano, Italy.,Division of Immunology, Transplantation and Infectious Diseases, IRCCS Ospedale San Raffaele, Milano, Italy
| | - Norma Maugeri
- Università Vita-Salute San Raffaele, Milano, Italy.,Division of Immunology, Transplantation and Infectious Diseases, IRCCS Ospedale San Raffaele, Milano, Italy
| |
Collapse
|
5
|
Campana L, Starkey Lewis PJ, Pellicoro A, Aucott RL, Man J, O'Duibhir E, Mok SE, Ferreira-Gonzalez S, Livingstone E, Greenhalgh SN, Hull KL, Kendall TJ, Vernimmen D, Henderson NC, Boulter L, Gregory CD, Feng Y, Anderton SM, Forbes SJ, Iredale JP. The STAT3-IL-10-IL-6 Pathway Is a Novel Regulator of Macrophage Efferocytosis and Phenotypic Conversion in Sterile Liver Injury. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2018; 200:1169-1187. [PMID: 29263216 PMCID: PMC5784823 DOI: 10.4049/jimmunol.1701247] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 11/25/2017] [Indexed: 12/20/2022]
Abstract
The disposal of apoptotic bodies by professional phagocytes is crucial to effective inflammation resolution. Our ability to improve the disposal of apoptotic bodies by professional phagocytes is impaired by a limited understanding of the molecular mechanisms that regulate the engulfment and digestion of the efferocytic cargo. Macrophages are professional phagocytes necessary for liver inflammation, fibrosis, and resolution, switching their phenotype from proinflammatory to restorative. Using sterile liver injury models, we show that the STAT3-IL-10-IL-6 axis is a positive regulator of macrophage efferocytosis, survival, and phenotypic conversion, directly linking debris engulfment to tissue repair.
Collapse
Affiliation(s)
- Lara Campana
- Medical Research Council Centre for Inflammation Research, University of Edinburgh, Edinburgh EH16 4TJ, United Kingdom;
- Medical Research Council Centre for Regenerative Medicine, University of Edinburgh, Edinburgh EH16 4UU, United Kingdom
| | - Philip J Starkey Lewis
- Medical Research Council Centre for Regenerative Medicine, University of Edinburgh, Edinburgh EH16 4UU, United Kingdom
| | - Antonella Pellicoro
- Medical Research Council Centre for Inflammation Research, University of Edinburgh, Edinburgh EH16 4TJ, United Kingdom
| | - Rebecca L Aucott
- Medical Research Council Centre for Inflammation Research, University of Edinburgh, Edinburgh EH16 4TJ, United Kingdom
| | - Janet Man
- Medical Research Council Centre for Regenerative Medicine, University of Edinburgh, Edinburgh EH16 4UU, United Kingdom
| | - Eoghan O'Duibhir
- Medical Research Council Centre for Regenerative Medicine, University of Edinburgh, Edinburgh EH16 4UU, United Kingdom
| | - Sarah E Mok
- University of Edinburgh, Edinburgh EH16 4SB, United Kingdom
| | - Sofia Ferreira-Gonzalez
- Medical Research Council Centre for Regenerative Medicine, University of Edinburgh, Edinburgh EH16 4UU, United Kingdom
| | - Eilidh Livingstone
- Medical Research Council Centre for Regenerative Medicine, University of Edinburgh, Edinburgh EH16 4UU, United Kingdom
| | - Stephen N Greenhalgh
- Medical Research Council Centre for Inflammation Research, University of Edinburgh, Edinburgh EH16 4TJ, United Kingdom
| | - Katherine L Hull
- University Hospitals of Leicester, Leicester LE3 9QP, United Kingdom
| | - Timothy J Kendall
- Medical Research Council Centre for Inflammation Research, University of Edinburgh, Edinburgh EH16 4TJ, United Kingdom
- Division of Pathology, University of Edinburgh, Edinburgh EH4 2XU, United Kingdom
| | - Douglas Vernimmen
- Developmental Biology Division, The Roslin Institute, University of Edinburgh, Edinburgh EH25 9RG, United Kingdom
| | - Neil C Henderson
- Medical Research Council Centre for Inflammation Research, University of Edinburgh, Edinburgh EH16 4TJ, United Kingdom
| | - Luke Boulter
- Medical Research Council Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, United Kingdom; and
| | - Christopher D Gregory
- Medical Research Council Centre for Inflammation Research, University of Edinburgh, Edinburgh EH16 4TJ, United Kingdom
| | - Yi Feng
- Medical Research Council Centre for Inflammation Research, University of Edinburgh, Edinburgh EH16 4TJ, United Kingdom
| | - Stephen M Anderton
- Medical Research Council Centre for Inflammation Research, University of Edinburgh, Edinburgh EH16 4TJ, United Kingdom
| | - Stuart J Forbes
- Medical Research Council Centre for Inflammation Research, University of Edinburgh, Edinburgh EH16 4TJ, United Kingdom
- Medical Research Council Centre for Regenerative Medicine, University of Edinburgh, Edinburgh EH16 4UU, United Kingdom
| | - John P Iredale
- Medical Research Council Centre for Inflammation Research, University of Edinburgh, Edinburgh EH16 4TJ, United Kingdom
- Senate House, University of Bristol, Bristol BS8 1TH, United Kingdom
| |
Collapse
|
6
|
Vezzoli M, Sciorati C, Campana L, Monno A, Doglio MG, Rigamonti E, Corna G, Touvier T, Castiglioni A, Capobianco A, Mantovani A, Manfredi AA, Garlanda C, Rovere-Querini P. The clearance of cell remnants and the regeneration of the injured muscle depend on soluble pattern recognition receptor PTX3. Mol Med 2016; 22:809-820. [PMID: 27900389 DOI: 10.2119/molmed.2016.00002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2016] [Accepted: 09/29/2016] [Indexed: 12/27/2022] Open
Abstract
OBJECTIVE The signals causing the resolution of muscle inflammation are only partially characterized. The long pentraxin PTX3, which modulates leukocyte recruitment and activation, could contribute. METHODS We analysed the expression of ptx3 after muscle injury and verified whether hematopoietic precursors are a source of the protein. The kinetics of regeneration and leukocytes infiltration, the accumulation of cell remnants and anti-histidyl-t-RNA synthetase autoantibodies were compared in wild-type and ptx3-deficient mice. RESULTS Ptx3 expression was up-regulated three-five days after injury and restricted to the extracellular matrix. Cellular debris and leukocytes persisted in the muscle of ptx3-deficient mice for a long time after wild-type animals had healed. ptx3-deficient macrophages expressed receptors involved in apoptotic cell clearance and engulfed dead cells in vitro. Accumulation of cell debris in a pro-inflammatory microenvironment was not sufficient to elicit autoantibodies. CONCLUSION PTX3 generated in response to muscle injury prompts the clearance of debris and the termination of the inflammatory response.
Collapse
Affiliation(s)
- Michela Vezzoli
- Division of Immunology, Transplantation and Infectious Disease, San Raffaele Scientific Institute, Milano, Italy
| | - Clara Sciorati
- Division of Immunology, Transplantation and Infectious Disease, San Raffaele Scientific Institute, Milano, Italy
| | - Lara Campana
- Division of Immunology, Transplantation and Infectious Disease, San Raffaele Scientific Institute, Milano, Italy
| | - Antonella Monno
- Division of Immunology, Transplantation and Infectious Disease, San Raffaele Scientific Institute, Milano, Italy
| | - Maria Giulia Doglio
- Division of Immunology, Transplantation and Infectious Disease, San Raffaele Scientific Institute, Milano, Italy
| | - Elena Rigamonti
- Division of Immunology, Transplantation and Infectious Disease, San Raffaele Scientific Institute, Milano, Italy
| | - Gianfranca Corna
- Division of Immunology, Transplantation and Infectious Disease, San Raffaele Scientific Institute, Milano, Italy
| | - Thierry Touvier
- Division of Immunology, Transplantation and Infectious Disease, San Raffaele Scientific Institute, Milano, Italy
| | - Alessandra Castiglioni
- Division of Immunology, Transplantation and Infectious Disease, San Raffaele Scientific Institute, Milano, Italy
| | - Annalisa Capobianco
- Division of Immunology, Transplantation and Infectious Disease, San Raffaele Scientific Institute, Milano, Italy
| | - Alberto Mantovani
- Humanitas Clinical and Research Center, Rozzano, Milano, Italy.,Humanitas University, Rozzano, Milan, Italy
| | - Angelo A Manfredi
- Division of Immunology, Transplantation and Infectious Disease, San Raffaele Scientific Institute, Milano, Italy.,Vita-Salute San Raffaele University, School of Medicine, Milano, Italy
| | | | - Patrizia Rovere-Querini
- Division of Immunology, Transplantation and Infectious Disease, San Raffaele Scientific Institute, Milano, Italy.,Vita-Salute San Raffaele University, School of Medicine, Milano, Italy
| |
Collapse
|
7
|
Cell death, clearance and immunity in the skeletal muscle. Cell Death Differ 2016; 23:927-37. [PMID: 26868912 DOI: 10.1038/cdd.2015.171] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 12/14/2015] [Accepted: 12/16/2015] [Indexed: 12/22/2022] Open
Abstract
The skeletal muscle is an immunologically unique tissue. Leukocytes, virtually absent in physiological conditions, are quickly recruited into the tissue upon injury and persist during regeneration. Apoptosis, necrosis and autophagy coexist in the injured/regenerating muscles, including those of patients with neuromuscular disorders, such as inflammatory myopathies, dystrophies, metabolic and mitochondrial myopathies and drug-induced myopathies. Macrophages are able to alter their function in response to microenvironment conditions and as a consequence coordinate changes within the tissue from the early injury throughout regeneration and eventual healing, and regulate the activation and the function of stem cells. Early after injury, classically activated macrophages ('M1') dominate the picture. Alternatively activated M2 macrophages predominate during resolution phases and regulate the termination of the inflammatory responses. The dynamic M1/M2 transition is increasingly felt to be the key to the homeostasis of the muscle. Recognition and clearance of debris originating from damaged myofibers and from dying stem/progenitor cells, stromal cells and leukocytes are fundamental actions of macrophages. Clearance of apoptotic cells and M1/M2 transition are causally connected and represent limiting steps for muscle healing. The accumulation of apoptotic cells, which reflects their defective clearance, has been demonstrated in various tissues to prompt autoimmunity against intracellular autoantigens. In the muscle, in the presence of type I interferon, apoptotic myoblasts indeed cause the production of autoantibodies, lymphocyte infiltration and continuous cycles of muscle injury and regeneration, mimicking human inflammatory myopathies. The clearance of apoptotic cells thus modulates the homeostatic response of the skeletal muscle to injury. Conversely, defects in the process may have deleterious local effects, guiding maladaptive tissue remodeling with collagen and fat accumulation and promoting autoimmunity itself. There is strong promise for novel treatments based on new knowledge of cell death, clearance and immunity in the muscle.
Collapse
|
8
|
Munoz LE, Herrmann M, Berens C. Dying autologous cells as instructors of the immune system. Clin Exp Immunol 2015; 179:1-4. [PMID: 25354655 DOI: 10.1111/cei.12478] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/28/2014] [Indexed: 12/20/2022] Open
Abstract
In an organism, cell death occurs at many different sites and in many different forms. It is frequently part of normal development or serves to maintain cell homeostasis. In other cases, cell death not only occurs due to injury, disease or infection, but also as a consequence of various therapeutic interventions. However, in all of these scenarios, the immune system has to react to the dying and dead cells and decide whether to mount an immune response, to remain quiet or to initiate healing and repopulation. This is essential for the organism, testified by many diseases that are associated with malfunctioning in the cell death process, the corpse removal, or the ensuing immune responsiveness. Therefore, dying cells generally have to be considered as instructors of the immune system. How this happens and which signals and pathways contribute to modulate or shape the immune response is still elusive in many conditions. The articles presented in this Special Issue address such open questions. They highlight that the context in which cell death occurs will not only influence the cell death process itself, but also affect the surrounding cellular milieu, how the generation and presence of 'eat me' signals can have an impact on cell clearance, and that the exact nature of the residual 'debris' and how it is processed are fundamental to determining the immunological consequences. Hopefully, these articles initiate new approaches and new experiments to complete our understanding of how cell death and the immune system interact with each other.
Collapse
Affiliation(s)
- L E Munoz
- Department of Internal Medicine 3 - Rheumatology and Immunology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | | | | |
Collapse
|
9
|
Rothlin CV, Carrera-Silva EA, Bosurgi L, Ghosh S. TAM receptor signaling in immune homeostasis. Annu Rev Immunol 2015; 33:355-91. [PMID: 25594431 DOI: 10.1146/annurev-immunol-032414-112103] [Citation(s) in RCA: 301] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The TAM receptor tyrosine kinases (RTKs)-TYRO3, AXL, and MERTK-together with their cognate agonists GAS6 and PROS1 play an essential role in the resolution of inflammation. Deficiencies in TAM signaling have been associated with chronic inflammatory and autoimmune diseases. Three processes regulated by TAM signaling may contribute, either independently or collectively, to immune homeostasis: the negative regulation of the innate immune response, the phagocytosis of apoptotic cells, and the restoration of vascular integrity. Recent studies have also revealed the function of TAMs in infectious diseases and cancer. Here, we review the important milestones in the discovery of these RTKs and their ligands and the studies that underscore the functional importance of this signaling pathway in physiological immune settings and disease.
Collapse
|