Fibroblasts and mesenchymal cells

Author(s):  
Andrew Filer ◽  
Maria Juarez ◽  
Christopher Buckley

In order to understand and explore the function and roles of fibroblasts, it is necessary to understand their lineage relationships to other mesenchymal cells. Fibroblasts are ubiquitous non-epithelial, non-endothelial, and non-haematopoietic adherent cells that have the capacity to produce and remodel extracellular matrix. In addition to their well-known ’landscaping’ function which determines the unique structure and function of different organs, they play an important role in wound healing, immune tolerance, and disease. In cancer, epithelial-stromal interactions have been implicated in disease initiation and progression. In rheumatoid arthritis, synovial fibroblasts at diseased sites become persistently activated and behave abnormally, orchestrating joint inflammation and contributing to joint destruction. Recent evidence suggests that the activated phenotype of fibroblasts in pathology may result from epigenetic programming, which is becoming a major focus for development of new therapeutics.

2005 ◽  
Vol 11 (5) ◽  
pp. 563-568 ◽  
Author(s):  
Ingmar Meinecke ◽  
Edita Rutkauskaite ◽  
Steffen Gay ◽  
Thomas Pap

2021 ◽  
Vol 41 (1) ◽  
Author(s):  
Haruka Tsuchiya ◽  
Mineto Ota ◽  
Keishi Fujio

Abstract Background Rheumatoid arthritis (RA) is an autoimmune disease characterized by tumor-like hyperplasia and inflammation of the synovium, which causes synovial cell invasion into the bone and cartilage. In RA pathogenesis, various molecules in effector cells (i.e., immune cells and mesenchymal cells) are dysregulated by genetic and environmental factors. Synovial fibroblasts (SFs), the most abundant resident mesenchymal cells in the synovium, are the major local effectors of the destructive joint inflammation and exert their effects through the pathogenic production of molecules such as interleukin-6. Main body To date, more than 100 RA susceptibility loci have been identified in genome-wide association studies (GWASs), and finding novel therapeutic targets utilizing genome analysis is considered a promising approach because some candidate causal genes identified by GWASs have previously been established as therapeutic targets. For further exploration of RA-responsible cells and cell type-specific therapeutic targets, integrated analysis (or functional genome analysis) of the genome and intermediate traits (e.g., transcriptome and epigenome) is crucial. Conclusion This review builds on the existing knowledge regarding the epigenomic abnormalities in RASFs and discusses the recent advances in single-cell analysis, highlighting the prospects of SFs as targets for safer and more effective therapies against RA.


Author(s):  
Leslie Baumann ◽  
Eric F Bernstein ◽  
Anthony S Weiss ◽  
Damien Bates ◽  
Shannon Humphrey ◽  
...  

Abstract Elastin is the main component of elastic fibers, which provide stretch, recoil, and elasticity to the skin. Normal levels of elastic fiber production, organization, and integration with other cutaneous extracellular matrix proteins, proteoglycans, and glycosaminoglycans are integral to maintaining healthy skin structure, function, and youthful appearance. Although elastin has very low turnover, its production decreases after individuals reach maturity and it is susceptible to damage from many factors. With advancing age and exposure to environmental insults, elastic fibers degrade. This degradation contributes to the loss of the skin’s structural integrity; combined with subcutaneous fat loss, this results in looser, sagging skin, causing undesirable changes in appearance. The most dramatic changes occur in chronically sun-exposed skin, which displays sharply altered amounts and arrangements of cutaneous elastic fibers, decreased fine elastic fibers in the superficial dermis connecting to the epidermis, and replacement of the normal collagen-rich superficial dermis with abnormal clumps of solar elastosis material. Disruption of elastic fiber networks also leads to undesirable characteristics in wound healing, and the worsening structure and appearance of scars and stretch marks. Identifying ways to replenish elastin and elastic fibers should improve the skin’s appearance, texture, resiliency, and wound-healing capabilities. However, few therapies are capable of repairing elastic fibers or substantially reorganizing the elastin/microfibril network. This review describes the clinical relevance of elastin in the context of the structure and function of healthy and aging skin, wound healing, and scars and introduces new approaches being developed to target elastin production and elastic fiber formation.


2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 1054.1-1054
Author(s):  
M. Schmeller ◽  
M. Diller ◽  
R. Hasseli ◽  
A. Knothe ◽  
S. Rehart ◽  
...  

Background:One of the key mechanisms in the pathogenesis of rheumatoid arthritis (RA) is the interaction of macrophages and synovial fibroblasts during joint inflammation. Increased synergistic proinflammatory activity of both cell types leads to the release of high levels of proinflammatory cytokines, especially of interleukin-6 (IL-6), and of matrix degrading enzymes. If this mechanism is uncontrolled, progressive destruction of articular cartilage and bone will take place.In active disease, immediate anti-inflammatory treatment with glucocorticoids is usually replaced by disease-modifying anti-rheumatic drugs (DMARDS), especially by methotrexate (MTX) and biologics such as TNF-α- or IL-6-inhibitors. This led to great improvements in prognosis and outcome for RA patients. However, about 40% of patients experience no remission or suffer from side effects of medication. To optimize established substances and to develop new treatment strategies, it is necessary to understand the mechanisms underlying the limited therapeutic effects.Objectives:Evaluation of the effect of prednisolone, MTX, adalimumab, tocilizumab on IL-6 secretion by RA synovial fibroblasts (RASF) and macrophages.Methods:RA synovium was used for RASF isolation. Peripheral blood mononuclear cells (PBMCs) were isolated from blood of healthy donors and RA patients by using Ficoll© medium followed by density gradient centrifugation. Mononuclear cells were seeded on six well plates (6x10^6/well) and incubated for one week. Then they were stimulated with Interferon-у (20 ng/ml) and LPS (50 ng/ml) for 48h to initiate differentiation into proinflammatory M1 macrophages. The M1 macrophages were co-cultured with RASF (100.000/well) and different treatments added (prednisolone: 10, 25, 50, 75, 100 nM, 1 µM; adalimumab: 100, 500 µg/ml; tocilizumab: 1, 5 µg/ml; MTX: 0,5, 1, 5, 10, 100 nM, 1µM). After 24h culture supernatants were collected and IL-6- and TNFα-ELISAs were performed.Results:IL-6 concentrations of untreated controls were comparable, regardless whether M1 macrophages from healthy donors or RA-patients were used for co-culture. Prednisolone reduced co-culture-induced IL-6 up to 56% (p<0.001) in co-culture of RASF and M1 macrophages of healthy donors and up to 60% (p<0.001) in co-culture of RASF and RA M1 macrophages. Adalimumab reduced IL-6 up to 28% (p<0.05) in M1 of healthy donors and up to 45% (p<0.01) in RA M1 macrophage co-cultures. A minor reduction by 10-20% of IL-6 was observed with tocilizumab and no significant effect could be achieved after treatment with MTX.Conclusion:Prednisolone and adalimumab clearly decrease but do not eliminate proinflammatory synergistic activity of RASF and M1 macrophages. These results confirm the clinical observation, that there is a large number of RA-patients that independent of anti-inflammatory treatment still suffer from low-level joint inflammation.The synergistic proinflammatory activity of M1 macrophages and RASF seems to be a complex and multifactorial mechanism that is difficult to eliminate by a single treatment substance. Since it is one of the key mechanisms in RA pathogenesis, there is a critical need to investigate how therapy effects could be optimized. This study confirmed RASFs as one of the leading effector cells of increased synergistic proinflammatory activity, thus underlining their promising role as a treatment target in rheumatoid arthritis.Disclosure of Interests:None declared


2006 ◽  
Vol 203 (2) ◽  
pp. 325-335 ◽  
Author(s):  
Tetsuya Honda ◽  
Eri Segi-Nishida ◽  
Yoshiki Miyachi ◽  
Shuh Narumiya

Prostaglandin (PG)I2 (prostacyclin [PGI]) and PGE2 are abundantly present in the synovial fluid of rheumatoid arthritis (RA) patients. Although the role of PGE2 in RA has been well studied, how much PGI2 contributes to RA is little known. To examine this issue, we backcrossed mice lacking the PGI receptor (IP) to the DBA/1J strain and subjected them to collagen-induced arthritis (CIA). IP-deficient (IP−/−) mice exhibited significant reduction in arthritic scores compared with wild-type (WT) mice, despite anti-collagen antibody production and complement activation similar to WT mice. IP−/− mice also showed significant reduction in contents of proinflammatory cytokines, such as interleukin (IL)-6 in arthritic paws. Consistently, the addition of an IP agonist to cultured synovial fibroblasts significantly enhanced IL-6 production and induced expression of other arthritis-related genes. On the other hand, loss or inhibition of each PGE receptor subtype alone did not affect elicitation of inflammation in CIA. However, a partial but significant suppression of CIA was achieved by the combined inhibition of EP2 and EP4. Our results show significant roles of both PGI2-IP and PGE2-EP2/EP4 signaling in the development of CIA, and suggest that inhibition of PGE2 synthesis alone may not be sufficient for suppression of RA symptoms.


2021 ◽  
Author(s):  
Søren Lomholt ◽  
Morten A. Nielsen ◽  
Maithri P. Aspari ◽  
Peter B. Jørgensen ◽  
Adam P. Croft ◽  
...  

Fibroblasts like synoviocytes (FLS) play several significant roles in rheumatoid arthritis (RA) pathophysiology. This chapter will describe known roles of FLS in disease initiation, joint inflammation, disease persistence and joint destruction. It will describe the newly characterized subsets of FLS based on single cell RNA sequencing studies, and their association to specific aspects of the disease. Finally, we will discuss the future of targeting FLS in the treatment of RA. The FLS in the synovial lining layer are identified by surface complement decay-accelerating factor (CD55) along with lubricin and metallopeptidase expression. Pathological activation of this lining layer subset result in bone and cartilage damage in mice. FLS of the sublining layer are often characterized by THY1 expression, but recent studies have highlighted a heterogeneity where several distinct subsets are identified by additional markers. Sublining FLS expressing human leukocyte antigen-DRA (HLA-DRA) produce C-X-C motif chemokine 12 (CXCL12) and receptor activator of nuclear factor-κB ligand (RANKL) and seems to constitute a pro-inflammatory subset that is associated with inflammation and tertiary lymphoid structures. Another subset of FLS characterized by CD34 expression may discriminate a common progenitor fibroblast subset. Taken together, studies isolating and characterizing gene expression in synovial FLS report both associations of unknown importance and markers that may impose protective or destructive features. This supports evidence of FLS as active players in RA pathology capable of cellular recruitment, local cellular crosstalk and promotion of joint destruction. These discoveries may serve as an atlas for synovial activation in RA and have identified several potential fibroblast markers for the development of targeted treatment.


2020 ◽  
Author(s):  
Yilin Wang ◽  
Aneesah Khan ◽  
Aristotelis Antonopoulos ◽  
Laura Bouché ◽  
Christopher D Buckley ◽  
...  

AbstractIn healthy joints, synovial fibroblasts (SFs) provide the microenvironment required to mediate homeostasis but are recognized to adopt a pathological role in rheumatoid arthritis (RA), promoting the infiltration and activation of immune cells to perpetuate local inflammation, pain and joint destruction. Carbohydrates (glycans) attached to cell surface proteins are fundamental regulators of cellular interactions between stromal and immune cells, but very little is known about the glycome of SFs or how glycosylation regulates their biology. Here we fill these gaps in our understanding of stromal guided pathophysiology by systematically mapping glycosylation pathways in healthy and arthritic SFs. We used a combination of transcriptomic and glycomic analysis to show that transformation of fibroblasts into pro-inflammatory cells in RA is associated with profound glycan remodeling, a process that involves reduction of α2-6 terminal sialylation that is mostly mediated by TNFα-dependent inhibition of the glycosyltransferase ST6Gal1. We also show that sialylation of SFs correlates with distinct disease stages and SFs functional subsets in both human RA and models of mouse arthritis. We propose that pro-inflammatory cytokines in the joint remodel the SF-glycome, transforming a regulatory tissue intended to preserve local homeostasis, into an under-sialylated and highly pro-inflammatory microenvironment that contributes to an amplificatory inflammatory network that perpetuates chronic inflammation. These results highlight the importance of cell glycosylation in stromal immunology.


Cells ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 953 ◽  
Author(s):  
Marzena Ciechomska ◽  
Leszek Roszkowski ◽  
Wlodzimierz Maslinski

Rheumatoid arthritis (RA) is a long-term autoimmune disease of unknown etiology that leads to progressive joint destruction and ultimately to disability. RA affects as much as 1% of the population worldwide. To date, RA is not a curable disease, and the mechanisms responsible for RA development have not yet been well understood. The development of more effective treatments and improvements in the early diagnosis of RA is direly needed to increase patients’ functional capacity and their quality of life. As opposed to genetic mutation, epigenetic changes, such as DNA methylation, are reversible, making them good therapeutic candidates, modulating the immune response or aggressive synovial fibroblasts (FLS—fibroblast-like synoviocytes) activity when it is necessary. It has been suggested that DNA methylation might contribute to RA development, however, with insufficient and conflicting results. Besides, recent studies have shown that circulating cell-free methylated DNA (ccfDNA) in blood offers a very convenient, non-invasive, and repeatable “liquid biopsy”, thus providing a reliable template for assessing molecular markers of various diseases, including RA. Thus, epigenetic therapies controlling autoimmunity and systemic inflammation may find wider implications for the diagnosis and management of RA. In this review, we highlight current challenges associated with the treatment of RA and other autoimmune diseases and discuss how targeting DNA methylation may improve diagnostic, prognostic, and therapeutic approaches.


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