scholarly journals Osteoimmunology: Interactions of the Bone and Immune System

2008 ◽  
Vol 29 (4) ◽  
pp. 403-440 ◽  
Author(s):  
Joseph Lorenzo ◽  
Mark Horowitz ◽  
Yongwon Choi

Abstract Bone and the immune system are both complex tissues that respectively regulate the skeleton and the body’s response to invading pathogens. It has now become clear that these organ systems often interact in their function. This is particularly true for the development of immune cells in the bone marrow and for the function of bone cells in health and disease. Because these two disciplines developed independently, investigators in each don’t always fully appreciate the significance that the other system has on the function of the tissue they are studying. This review is meant to provide a broad overview of the many ways that bone and immune cells interact so that a better understanding of the role that each plays in the development and function of the other can develop. It is hoped that an appreciation of the interactions of these two organ systems will lead to better therapeutics for diseases that affect either or both.

2002 ◽  
Vol 173 (3) ◽  
pp. 387-394 ◽  
Author(s):  
JE Compston

Bone and bone marrow, although often regarded as separate systems, function as a single unit. Cells in the bone marrow are the precursors of bone remodelling cells and exert an important regulatory role both on their own development and the remodelling process, acting as mediators for the effects of systemic and local factors. Other cells, such as immune cells and megakaryocytes, also contribute to the regulation of bone cell development and activity. Many diseases that affect the bone marrow have profound effects on bone, involving interactions between abnormal and normal marrow cells and those of bone. Although recent advances in bone physiology have produced new insights into the relationship between bone marrow and bone cells, much remains to be learnt about the mechanisms by which marrow and bone act in synergy to regulate bone remodelling, both in health and disease.


2020 ◽  
Vol 38 (1) ◽  
pp. 727-757 ◽  
Author(s):  
Mirjana Efremova ◽  
Roser Vento-Tormo ◽  
Jong-Eun Park ◽  
Sarah A. Teichmann ◽  
Kylie R. James

Immune cells are characterized by diversity, specificity, plasticity, and adaptability—properties that enable them to contribute to homeostasis and respond specifically and dynamically to the many threats encountered by the body. Single-cell technologies, including the assessment of transcriptomics, genomics, and proteomics at the level of individual cells, are ideally suited to studying these properties of immune cells. In this review we discuss the benefits of adopting single-cell approaches in studying underappreciated qualities of immune cells and highlight examples where these technologies have been critical to advancing our understanding of the immune system in health and disease.


Nutrients ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 850
Author(s):  
María Ángeles Martín ◽  
Sonia Ramos

Flavanols are natural occurring polyphenols abundant in fruits and vegetables to which have been attributed to beneficial effects on health, and also against metabolic diseases, such as diabetes, obesity and metabolic syndrome. These positive properties have been associated to the modulation of different molecular pathways, and importantly, to the regulation of immunological reactions (pro-inflammatory cytokines, chemokines, adhesion molecules, nuclear factor-κB [NF-κB], inducible enzymes), and the activity of cells of the immune system. In addition, flavanols can modulate the composition and function of gut microbiome in a prebiotic-like manner, resulting in the positive regulation of metabolic pathways and immune responses, and reduction of low-grade chronic inflammation. Moreover, the biotransformation of flavanols by gut bacteria increases their bioavailability generating a number of metabolites with potential to affect human metabolism, including during metabolic diseases. However, the exact mechanisms by which flavanols act on the microbiota and immune system to influence health and disease remain unclear, especially in humans where these connections have been scarcely explored. This review seeks to summarize recent advances on the complex interaction of flavanols with gut microbiota, immunity and inflammation focus on metabolic diseases.


2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii124-ii124
Author(s):  
Jan Remsik ◽  
Xinran Tong ◽  
Ugur Sener ◽  
Danille Isakov ◽  
Yudan Chi ◽  
...  

Abstract For decades, the central nervous system was considered to be an immune privileged organ with limited access to systemic immunity. However, the leptomeninges, the cerebrospinal fluid (CSF)-filled anatomical structure that protects the brain and spinal cord, represent a relatively immune-rich environment. Despite the presence of immune cells, complications in the CSF, such as infectious meningitis and a neurological development of cancer known as leptomeningeal metastasis, are difficult to treat and are frequently fatal. We show that immune cells entering the CSF are held in an ‘idle’ state that limits their cytotoxic arsenal and antigen presentation machinery. To understand this underappreciated neuroanatomic niche, we used unique mouse models and rare patient samples to characterize its cellular composition and critical signaling events in health and disease at a single-cell resolution. Revealing the mediators of CSF immune response will allow us to re-evaluate current therapeutic protocols and employ rational combinations with immunotherapies, therefore turning the patient’s own immune system into an active weapon against pathogens and cancer.


2020 ◽  
Author(s):  
Luca Pangrazzi ◽  
Erin Naismith ◽  
Carina Miggitsch ◽  
Jose’ Antonio Carmona Arana ◽  
Michael Keller ◽  
...  

Abstract Background. Obesity has been associated with chronic inflammation and oxidative stress. Both conditions play a determinant role in the pathogenesis of age-related diseases, such as immunosenescence. Adipose tissue can modulate the function of the immune system with the secretion of molecules influencing the phenotype of immune cells. The importance of the bone marrow (BM) in the maintenance of antigen-experienced adaptive immune cells has been documented in mice. Recently, some groups have investigated the survival of effector/memory T cells in the human BM. Despite this, whether high body mass index (BMI) may affect immune cells in the BM and the production of molecules supporting the maintenance of these cells it is unknown.Methods. Using flow cytometry, the frequency and the phenotype of immune cell populations were measured in paired BM and PB samples obtained from persons with different BMI. Furthermore, the expression of BM cytokines was assessed. The influence of cytomegalovirus (CMV) on T cell subsets was additionally considered, dividing the donors into the CMV- and CMV+ groups.Results. Our study suggests that increased BMI may affect both the maintenance and the phenotype of adaptive immune cells in the BM. While the BM levels of IL-15 and IL-6, supporting the survival of highly differentiated T cells, and oxygen radicals increased in overweight persons, the production of IFNγ and TNF by CD8+ T cells was reduced. In addition, the frequency of B cells and CD4+ T cells positively correlated with BMI in the BM of CMV- persons. Finally, the frequency of several T cell subsets, and the expression of senescence/exhaustion markers within these subpopulations, were affected by BMI. In particular, the levels of bona fide memory T cells may be reduced in overweight persons.Conclusion. Our work suggests that, in addition to aging and CMV, obesity may represent an additional risk factor for immunosenescence in adaptive immune cells. Metabolic interventions may help in improving the fitness of the immune system in the elderly.


2020 ◽  
Author(s):  
Luca Pangrazzi ◽  
Erin Naismith ◽  
Carina Miggitsch ◽  
Jose’ Antonio Carmona Arana ◽  
Michael Keller ◽  
...  

Abstract Background. Obesity has been associated with chronic inflammation and oxidative stress. Both conditions play a determinant role in the pathogenesis of age-related diseases, such as immunosenescence. Adipose tissue can modulate the function of the immune system with the secretion of molecules influencing the phenotype of immune cells. Recently, the importance of the bone marrow (BM) in the maintenance of antigen-experienced adaptive immune cells has been documented. Despite this, whether high body mass index (BMI) may affect immune cells in the BM and the production of molecules supporting the maintenance of these cells it is unknown. Methods. Using flow cytometry, the frequency and the phenotype of immune cell populations were measured in paired BM and PB samples obtained from persons with different BMI. Furthermore, the expression of BM cytokines was assessed. The influence of cytomegalovirus (CMV) on T cell subsets was additionally considered, dividing the donors into the CMV - and CMV + groups. Results. Our study suggests that increased BMI may affect both the maintenance and the phenotype of adaptive immune cells in the BM. While the BM levels of IL-15 and IL-6, supporting the survival of highly differentiated T cells, and oxygen radicals increased in overweight persons, the production of IFNγ and TNF by CD8 + T cells was reduced. In addition, the frequency of B cells and CD4 + T cells positively correlated with BMI in the BM of CMV - persons. Finally, the frequency of several T cell subsets, and the expression of senescence/exhaustion markers within these subpopulations, were affected by BMI. In particular, the levels of bona fide memory T cells may be reduced in overweight persons. Conclusion. Our work suggests that obesity may represent an independent risk factor supporting immunosenescence, in addition to aging and CMV. Metabolic interventions may help in improving the fitness of the immune system in the elderly.


Rheumatology ◽  
2019 ◽  
Vol 58 (8) ◽  
pp. 1331-1343 ◽  
Author(s):  
Irene Di Ceglie ◽  
Nik N L Kruisbergen ◽  
Martijn H J van den Bosch ◽  
Peter L E M van Lent

AbstractBone erosion is one of the central hallmarks of RA and is caused by excessive differentiation and activation of osteoclasts. Presence of autoantibodies in seropositive arthritis is associated with radiographic disease progression. ICs, formed by autoantibodies and their antigens, activate Fcγ-receptor signalling in immune cells, and as such stimulate inflammation-mediated bone erosion. Interestingly, ICs can also directly activate osteoclasts by binding to FcγRs on their surface. Next to autoantibodies, high levels of alarmins, among which is S100A8/A9, are typical for RA and they can further activate the immune system but also directly promote osteoclast function. Therefore, IC-activated FcγRs and S100A8/A9 might act as partners in crime to stimulate inflammation and osteoclasts differentiation and function, thereby stimulating bone erosion. This review discusses the separate roles of ICs, FcγRs and alarmins in bone erosion and sheds new light on the possible interplay between them, which could fuel bone erosion.


1967 ◽  
Vol 125 (4) ◽  
pp. 703-720 ◽  
Author(s):  
J. L. Curry ◽  
J, J. Trentin ◽  
N. Wolf

The polycythemic repression of erythropoiesis and the restoration of erythropoiesis by specific stimulation were studied in the spleen colony system in irradiated mice. 1. A 5 day period of erythropoietin stimulation (exogenous erythropoietin) or repression (polycythemia) of the bone marrow donor only, does not significantly alter the number or type of colonies formed by the transplanted marrow cells. 2. Erythropoietin stimulation did not alter the number or type of endogenous colonies formed in mice receiving 580 R. Erythropoietin repression (polycythemia) markedly reduced the growth but not the number of erythroid colonies, while not affecting the other types of colonies formed endogenously. 3. Erythropoietin stimulation of the irradiated recipient during colony growth did not alter the number or type of spleen colonies formed by transplanted marrow. Erythropoietin repression by polycythemia during colony growth completely suppressed the appearance of morphologically erythroid colonies without significantly altering the incidence of the other colony types. This effect of polycythemia was completely prevented by exogenous erythropoietin. Irradiated mice are therefore presumed to be secreting sufficient erythropoietin for maximal erythroid colony development. 4. The erythroid colonies suppressed by polycythemia were recognizable as microscopic foci of undifferentiated cells. Exposure of these foci to erythropoietin stimulation at different periods in their development was manifested by different degrees of growth and differentiation, from which it is apparent that erythropoietin stimulates not only morphological differentiation but also rapid mitosis. Retransplantation of either erythroid or of neutrophilic primary spleen colonies gave rise to both erythroid and neutrophilic secondary spleen colonies. The percentage of erythroid secondary colonies was slightly but significantly higher among the progeny of transplanted erythroid primary colonies than among the progeny of transplanted neutrophilic primary colonies. On the basis of these and other results, a working hypothesis is proposed for factors controlling the growth and differentiation of spleen colonies from transplanted bone marrow. It is postulated that most but perhaps not all spleen colony-forming units are pluripotent hemopoietic stem cells. It is further postulated that hemopoietic-inductive microenvironments (HIM) of different kinds exist in both the spleen and the bone marrow, and that these determine the differentiation of pluripotent stem cells into each of the lines of hemopoietic differentiation. Erythropoietin therefore may "induce" erythroid differentiation of only those stem cells under the influence of an erythroid HIM. Alternatively erythropoietin may act only as a growth and function stimulant of those stem cells that have been "induced" by an erythroid HIM into a state of erythropoietin responsiveness. In the latter case morphological differentiation presumably results from the functional activity stimulated by ESF.


1969 ◽  
Vol 129 (5) ◽  
pp. 935-951 ◽  
Author(s):  
G. M. Shearer ◽  
G. Cudkowicz

Marrow cell suspensions of unprimed donor mice have been transplanted into X-irradiated syngeneic hosts. 5–46 days later, bone cavities and spleens contained regenerated cells of the immune system which required interaction with thymocytes (from intact donors) and antigen (SRBC) to form antigen-sensitive units (ASU) and to generate mature immunocytes. These cells were capable of differentiating either into direct or indirect hemolytic plaque-forming cells (PFC). The precursors of PFC regenerated earlier than the other cell type necessary for immunocompetence, the antigen-reactive cell (ARC). The latter was not found until 10 or more days after transplantation. Availability of ARC was inferred from PFC responses elicited by grafted mice challenged with SRBC at varying intervals. In a second series of experiments, graded numbers of marrow cells (ranging from 107 to 5 x 107) were transplanted with 5 x 107 or 108 thymocytes into irradiated mice, and SRBC were given 18 hr later. After 9–12 days the recipient spleens contained all or some of the following immunocytes: direct and indirect PFC, and hemagglutinating cluster-forming cells. The frequency of each immune response varied independently of the others, but in relation to the number of marrow cells grafted. This was interpreted to indicate that ASU formed in irradiated mice by interaction of marrow and thymus cells were similar to those of intact mice. In particular, they were specialized for the molecular class (IgM or IgG) and function (lysis or agglutination) of the antibody to be secreted by their descendent immunocytes. Hence, class-differentiation appeared to be conferred upon ASU by their marrow-derived components.


2021 ◽  
Vol 12 ◽  
Author(s):  
Javier Traba ◽  
Michael N. Sack ◽  
Thomas A. Waldmann ◽  
Olga M. Anton

Constitutive activity of the immune surveillance system detects and kills cancerous cells, although many cancers have developed strategies to avoid detection and to resist their destruction. Cancer immunotherapy entails the manipulation of components of the endogenous immune system as targeted approaches to control and destroy cancer cells. Since one of the major limitations for the antitumor activity of immune cells is the immunosuppressive tumor microenvironment (TME), boosting the immune system to overcome the inhibition provided by the TME is a critical component of oncotherapeutics. In this article, we discuss the main effects of the TME on the metabolism and function of immune cells, and review emerging strategies to potentiate immune cell metabolism to promote antitumor effects either as monotherapeutics or in combination with conventional chemotherapy to optimize cancer management.


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