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Bellomo A, Gentek R, Golub R, Bajénoff M. Macrophage-fibroblast circuits in the spleen. Immunol Rev 2021; 302:104-125. [PMID: 34028841 DOI: 10.1111/imr.12979] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 04/30/2021] [Accepted: 04/30/2021] [Indexed: 12/22/2022]
Abstract
Macrophages are an integral part of all organs in the body, where they contribute to immune surveillance, protection, and tissue-specific homeostatic functions. This is facilitated by so-called niches composed of macrophages and their surrounding stroma. These niches structurally anchor macrophages and provide them with survival factors and tissue-specific signals that imprint their functional identity. In turn, macrophages ensure appropriate functioning of the niches they reside in. Macrophages thus form reciprocal, mutually beneficial circuits with their cellular niches. In this review, we explore how this concept applies to the spleen, a large secondary lymphoid organ whose primary functions are to filter the blood and regulate immunity. We first outline the splenic micro-anatomy, the different populations of splenic fibroblasts and macrophages and their respective contribution to protection of and key physiological processes occurring in the spleen. We then discuss firmly established and potential cellular circuits formed by splenic macrophages and fibroblasts, with an emphasis on the molecular cues underlying their crosstalk and their relevance to splenic functionality. Lastly, we conclude by considering how these macrophage-fibroblast circuits might be impaired by aging, and how understanding these changes might help identify novel therapeutic avenues with the potential of restoring splenic functions in the elderly.
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Affiliation(s)
- Alicia Bellomo
- CIRI, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, École Normale Supérieure de Lyon, Univ Lyon, Lyon, France
| | - Rebecca Gentek
- Centre for Inflammation Research & Centre for Reproductive Health, The Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK
| | - Rachel Golub
- Inserm U1223, Institut Pasteur, Paris, France.,Lymphopoiesis Unit, Institut Pasteur, Paris, France
| | - Marc Bajénoff
- Aix Marseille Univ, CNRS, INSERM, CIML, Marseille, France
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Zhu M, Sun BH, Saar K, Simpson C, Troiano N, Dallas SL, Tiede-Lewis LM, Nevius E, Pereira JP, Weinstein RS, Tommasini SM, Insogna KL. Deletion of Rac in Mature Osteoclasts Causes Osteopetrosis, an Age-Dependent Change in Osteoclast Number, and a Reduced Number of Osteoblasts In Vivo. J Bone Miner Res 2016; 31:864-73. [PMID: 26496249 PMCID: PMC4826801 DOI: 10.1002/jbmr.2733] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 10/16/2015] [Accepted: 10/20/2015] [Indexed: 12/30/2022]
Abstract
Rac1 and Rac2 are thought to have important roles in osteoclasts. Therefore, mice with deletion of both Rac1 and Rac2 in mature osteoclasts (DKO) were generated by crossing Rac1(flox/flox) mice with mice expressing Cre in the cathepsin K locus and then mating these animals with Rac2(-/-) mice. DKO mice had markedly impaired tooth eruption. Bone mineral density (BMD) was increased 21% to 33% in 4- to 6-week-old DKO mice at all sites when measured by dual-energy X-ray absorptiometry (DXA) and serum cross-linked C-telopeptide (CTx) was reduced by 52%. The amount of metaphyseal trabecular bone was markedly increased in DKO mice, but the cortices were very thin. Spinal trabecular bone mass was increased. Histomorphometry revealed significant reductions in both osteoclast and osteoblast number and function in 4- to 6-week-old DKO animals. In 14- to 16-week-old animals, osteoclast number was increased, although bone density was further increased. DKO osteoclasts had severely impaired actin ring formation, an impaired ability to generate acid, and reduced resorptive activity in vitro. In addition, their life span ex vivo was reduced. DKO osteoblasts expressed normal differentiation markers except for the expression of osterix, which was reduced. The DKO osteoblasts mineralized normally in vitro, indicating that the in vivo defect in osteoblast function was not cell autonomous. Confocal imaging demonstrated focal disruption of the osteocytic dendritic network in DKO cortical bone. Despite these changes, DKO animals had a normal response to treatment with once-daily parathyroid hormone (PTH). We conclude that Rac1 and Rac2 have critical roles in skeletal metabolism.
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Affiliation(s)
- Meiling Zhu
- Department of Internal Medicine, Endocrinology, Yale School of Medicine, New Haven, CT, USA
| | - Ben-hua Sun
- Department of Internal Medicine, Endocrinology, Yale School of Medicine, New Haven, CT, USA
| | - Katarzyna Saar
- Department of Internal Medicine, Endocrinology, Yale School of Medicine, New Haven, CT, USA
| | - Christine Simpson
- Department of Internal Medicine, Endocrinology, Yale School of Medicine, New Haven, CT, USA
| | - Nancy Troiano
- Department of Orthopaedics and Rehabilitation, Yale School of Medicine, New Haven, CT, USA
| | - Sarah L Dallas
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, Kansas City, Kansas City, MO, USA
| | - LeAnn M Tiede-Lewis
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, Kansas City, Kansas City, MO, USA
| | - Erin Nevius
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA
| | - João P Pereira
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA
| | - Robert S Weinstein
- Department of Internal Medicine, University of Arkansas for Medical Sciences and the Central Arkansas Veterans Health Care System, Little Rock, AR, USA
| | - Steven M Tommasini
- Department of Orthopaedics and Rehabilitation, Yale School of Medicine, New Haven, CT, USA
| | - Karl L Insogna
- Department of Internal Medicine, Endocrinology, Yale School of Medicine, New Haven, CT, USA
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Hsu YH, Chang MS. The Therapeutic Potential of Anti-Interleukin-20 Monoclonal Antibody. Cell Transplant 2014; 23:631-9. [DOI: 10.3727/096368914x678319] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Interleukin (IL)-20, a member of the IL-10 family of cytokines, was discovered in 2001. IL-20 acts on multiple cell types by activating on a heterodimer receptor complex of either IL-20R1–IL-20R2 or IL-22R1–IL-20R2. Recent evidence indicates that IL-20's interaction with its receptors might have proinflammatory effects on chronic inflammatory diseases, particularly rheumatoid arthritis (RA), osteoporosis, and breast cancer. Updated information about IL-20, such as its identification, expression, receptors, signaling, and biological activities, is illustrated in this review based on our research and the data available in the literature. IL-20 is a pleiotropic cytokine, which promotes inflammation, angiogenesis, and chemotaxis. IL-20 also regulates osteoclast differentiation by altering the receptor activator of NF-κB (RANK) and RANK ligand (RANKL) axis. Inflammation, angiogenesis, and osteoclastogenesis are critical for the pathogenesis of RA, osteoporosis, and breast cancer-induced osteolysis. Based on the in vitro and in vivo data and clinical samples, we demonstrated that IL-20 plays pivotal roles in these three diseases. In experimental models, anti-IL-20 monoclonal antibody ameliorates arthritis severity, protects against ovariectomized-induced bone loss, and inhibits breast tumor-induced osteolysis. This review presents the clinical implications of IL-20, which will lead to a better understanding of the biological functions of IL-20 in these diseases and provide new therapeutic options in the future.
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Affiliation(s)
- Yu-Hsiang Hsu
- Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Ming-Shi Chang
- Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
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LaBranche TP, Jesson MI, Radi ZA, Storer CE, Guzova JA, Bonar SL, Thompson JM, Happa FA, Stewart ZS, Zhan Y, Bollinger CS, Bansal PN, Wellen JW, Wilkie DP, Bailey SA, Symanowicz PT, Hegen M, Head RD, Kishore N, Mbalaviele G, Meyer DM. JAK inhibition with tofacitinib suppresses arthritic joint structural damage through decreased RANKL production. ACTA ACUST UNITED AC 2012; 64:3531-42. [DOI: 10.1002/art.34649] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Lampropoulos CE, Papaioannou I, D'Cruz DP. Osteoporosis--a risk factor for cardiovascular disease? Nat Rev Rheumatol 2012; 8:587-98. [PMID: 22890244 DOI: 10.1038/nrrheum.2012.120] [Citation(s) in RCA: 133] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Osteoporosis is a serious health problem worldwide that is associated with an increased risk of fractures and mortality. Vascular calcification is a well-defined independent risk factor for cardiovascular disease (CVD) and mortality. Major advances in our understanding of the pathophysiology of osteoporosis and vascular calcification indicate that these two processes share common pathogenetic mechanisms. Multiple factors including proteins (such as bone morphogenetic proteins, receptor activator of nuclear factor κB ligand, osteoprotegerin, matrix Gla protein and cathepsins), parathyroid hormone, phosphate, oxidized lipids and vitamins D and K are implicated in both bone and vascular metabolism, illustrating the interaction of these two, seemingly unrelated, conditions. Many clinical studies have now confirmed the correlation between osteoporosis and vascular calcification as well as the increased risk of CVD in patients with osteoporosis. Here, we explore the proposed mechanistic similarities between osteoporosis and vascular calcification and present an overview of the clinical data that support the interaction between these conditions.
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Affiliation(s)
- Christos E Lampropoulos
- Department of Internal Medicine, General Hospital of Nafplio, Kolokotroni and Asklipiou Streets, 21100 Nafplio, Greece
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Increased serum enzyme levels associated with kupffer cell reduction with no signs of hepatic or skeletal muscle injury. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 179:240-7. [PMID: 21703406 DOI: 10.1016/j.ajpath.2011.03.029] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2010] [Revised: 02/16/2011] [Accepted: 03/15/2011] [Indexed: 11/23/2022]
Abstract
Macrophage colony-stimulating factor (M-CSF) is a hematopoietic growth factor that is responsible for the survival and proliferation of monocytes and the differentiation of monocytes into macrophages, including Kupffer cells (KCs) in the liver. KCs play an important role in the clearance of several serum enzymes, including aspartate aminotransferase and creatine kinase, that are typically elevated as a result of liver or skeletal muscle injury. We used three distinct animal models to investigate the hypothesis that increases in the levels of serum enzymes can be the result of decreases in KCs in the apparent absence of hepatic or skeletal muscle injury. Specifically, neutralizing M-CSF activity via a novel human monoclonal antibody reduced the CD14(+)CD16(+) monocyte population, depleted KCs, and increased aspartate aminotransferase and creatine kinase serum enzyme levels in cynomolgus macaques. In addition, the treatment of rats with clodronate liposomes depleted KCs and led to increased serum enzyme levels, again without evidence of tissue injury. Finally, in the osteopetrotic (Csf1(op)/Csf1(op)) mice lacking functional M-CSF and having reduced levels of KCs, the levels of serum enzymes are higher than in wild-type littermates. Together, these findings support a mechanism for increases in serum enzyme levels through M-CSF regulation of tissue macrophage homeostasis without concomitant histopathological changes in either the hepatic or skeletal system.
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