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Introduction: Mesenchymal stem cells (MSCs) are adult, multipotent, stem cells with immunomodulatory properties. The mechanisms involved in the capacity of MSCs to inhibit the proliferation of proinflammatory T lymphocytes, which appear responsible for causing autoimmune disease, have yet to be fully elucidated. One of the underlying mechanisms studied recently is the ability of MSCs to generate T regulatory (Treg) cells in vitro and in vivo from activated peripheral blood mononuclear cells (PBMC), T-CD4+ and also T-CD8+ cells. In the present work we investigated the capacity of MSCs to generate Treg cells using T-CD4+ cells induced to differentiate toward the proinflammatory Th1 and Th17 lineages. Methods: MSCs were obtained from mouse bone marrow and characterized according to their surface antigen expression and their multilineage differentiation potential. CD4+ T cells isolated from mouse spleens were induced to differentiate into Th1 or Th17 cells and co-cultured with MSCs added at day 0, 2 or 4 of the differentiation processes. After six days, CD25, Foxp3, IL-17 and IFN-γ expression was assessed by flow cytometry and helios and neuropilin 1 mRNA levels were assessed by RT-qPCR. For the functional assays, the 'conditioned' subpopulation generated in the presence of MSCs was cultured with concanavalin A-activated CD4+ T cells labeled with carboxyfluorescein succinimidyl ester. Finally, we used the encephalomyelitis autoimmune diseases (EAE) mouse model, in which mice were injected with MSCs at day 18 and 30 after immunization. At day 50, the mice were euthanized and draining lymph nodes were extracted for Th1, Th17 and Treg detection by flow cytometry. Results: MSCs were able to suppress the proliferation, activation and differentiation of CD4+ T cells induced to differentiate into Th1 and Th17 cells. This substantial suppressive effect was associated with an increase of the percentage of functional induced CD4+CD25+Foxp3+ regulatory T cells and IL-10 secretion. However, using mature Th1 or Th17 cells our results demonstrated that while MSCs suppress the proliferation and phenotype of mature Th1 and Th17 cells they did not generate Treg cells. Finally, we showed that the beneficial effect observed following MSC injection in an EAE mouse model was associated with the suppression of Th17 cells and an increase in the percentage of CD4+CD25+Foxp3+ T lymphocytes when administrated at early stages of the disease. Conclusions: This study demonstrated that MSCs contribute to the generation of an immunosuppressive environment via the inhibition of proinflammatory T cells and the induction of T cells with a regulatory phenotype. Together, these results might have important clinical implications for inflammatory and autoimmune diseases. [ABSTRACT FROM AUTHOR]

Objective To examine the effect of different sources of Good Manufacturing Practice clinical grade adipose-derived mesenchymal stem cells (AD-MSCs) on inflammatory factors in osteoarthritic (OA) chondrocytes and synoviocytes. Methods AD-MSCs from infrapatellar Hoffa fat, subcutaneous (SC) hip fat, and SC abdominal fat were cocultured in Transwells with chondrocytes or synoviocytes. Inflammatory factors (interleukin-1β [IL-1β], tumor necrosis factor α, IL-6, CXCL1/growth-related oncogene α, CXCL8/IL-8, CCL2/monocyte chemotactic protein 1, CCL3/macrophage inflammatory protein 1α, and CCL5/RANTES) were evaluated by quantitative reverse transcription-polymerase chain reaction or multiplex bead-based immunoassay. The role of different immunomodulators was analyzed. Results All the inflammatory factors analyzed were down-modulated at the messenger RNA or protein level independently by all 3 AD-MSC sources or by allogeneic AD-MSCs used in coculture with chondrocytes or synoviocytes. Inflammatory factor down-modulation was observed only when AD-MSCs were cocultured with chondrocytes or synoviocytes that produced high levels of inflammatory factors, but no effect was observed in cells that produced low levels of those factors, thus highlighting a dependence of the AD-MSC effect on existing inflammation. The immunomodulators IL-10, IL-1 receptor antagonist, fibroblast growth factor 2, indoleamine 2,3-dioxygenase 1, and galectin 1 were not involved in AD-MSC effects, whereas the cyclooxygenase 2 (COX-2)/prostaglandin E2 (PGE2) pathway exerted a role in the mechanism of antiinflammatory AD-MSC action. Conclusion The antiinflammatory effects of AD-MSCs are probably not dependent on AD-MSC adipose tissue sources and donors but rather on the inflammatory status of OA chondrocytes and synoviocytes. AD-MSCs seem to be able to sense and respond to the local environment. Even though a combination of different molecules may be involved in AD-MSC effects, the COX-2/PGE2 pathway may play a role, suggesting that AD-MSCs may be useful for therapies in osteoarticular diseases. [ABSTRACT FROM AUTHOR]

The therapeutic potential of monoclonal antibodies for treating a variety of severe or life-threatening diseases is high. Although intravenous infusion appears the simplest and most obvious mode of administration, it is not applicable to many long-term treatments. It might be advantageously replaced by gene/cell therapies, however, rendering treatments cost-effective and eliminating the short- and long-term side-effects associated with injection of massive doses of antibodies. We have tested whether skin can potentially be used as an organ for production and systemic delivery of ectopic antibodies. Normal human primary keratinocytes were shown to be capable of synthesis and secretion of a model monoclonal antibody directed against human thyroglobulin upon retroviral gene transduction in vitro . Neo- epidermis reconstructed in vitro , either in cell culture inserts or on dermal substrates, from such modified keratinocytes also produced the monoclonal antibody. Interestingly, the latter could cross the epidermis basal layer and be released in culture fluids. Finally, grafting of epidermis reconstituted in vitro on dermal substrates to SCID mice permitted sustained monoclonal antibody delivery into the bloodstream to be achieved. Our data thus show that genetically engineered keratinocytes can potentially be used for genetic antibody-based immunotherapies. They also indicate that proteins as big as 150 kDa, after release by engineered keratinocytes into skin intercellular spaces, can migrate to the general circulation, which is potentially important for a number of other gene-based therapies. [ABSTRACT FROM AUTHOR]

Background: Systemic sclerosis (SSc) is a severe autoimmune disease for which mesenchymal stromal cells (MSCs)-based therapy was reported to reduce SSc-related symptoms in pre-clinical studies. Recently, extracellular vesicles released by MSCs (MSC-EVs) were shown to mediate most of their therapeutic effect. Here, we aimed at improving their efficacy by increasing the MSC-EV dose or by IFNγ-priming of MSCs. Methods: small size (ssEVs) and large size EVs (lsEVs) were recovered from murine MSCs that were pre-activated using 1 or 20 ng/mL of IFNγ. In the HOCl-induced model of SSc, mice were treated with EVs at day 21 and sacrificed at day 42. Lung and skin samples were collected for histological and molecular analyses. Results: increasing the dose of MSC-EVs did not add benefit to the dose previously reported to be efficient in SSc. By contrast, IFNγ pre-activation improved MSC-EVs-based treatment, essentially in the lungs. Low doses of IFNγ decreased the expression of fibrotic markers, while high doses improved remodeling and anti-inflammatory markers. IFNγ pre-activation upregulated iNos, IL1ra and Il6 in MSCs and ssEVs and the PGE2 protein in lsEVs. Conclusion: IFNγ-pre-activation improved the therapeutic effect of MSC-EVs preferentially in the lungs of SSc mice by modulating anti-inflammatory and anti-fibrotic markers. [ABSTRACT FROM AUTHOR]

Systemic sclerosis (SSc) is a complex disorder resulting from dysregulated interactions between the three main pathophysiological axes: fibrosis, immune dysfunction, and vasculopathy, with no specific treatment available to date. Adipose tissue-derived mesenchymal stromal cells (ASCs) and their extracellular vesicles (EVs) have proved efficacy in pre-clinical murine models of SSc. However, their precise action mechanism is still not fully understood. Because of the lack of availability of fibroblasts isolated from SSc patients (SSc-Fb), our aim was to determine whether a TGFβ1-induced model of human myofibroblasts (Tβ-Fb) could reproduce the characteristics of SSc-Fb and be used to evaluate the anti-fibrotic function of ASCs and their EVs. We found out that Tβ-Fb displayed the main morphological and molecular features of SSc-Fb, including the enlarged hypertrophic morphology and expression of several markers associated with the myofibroblastic phenotype. Using this model, we showed that ASCs were able to regulate the expression of most myofibroblastic markers on Tβ-Fb and SSc-Fb, but only when pre-stimulated with TGFβ1. Of interest, ASC-derived EVs were more effective than parental cells for improving the myofibroblastic phenotype. In conclusion, we provided evidence that Tβ-Fb are a relevant model to mimic the main characteristics of SSc fibroblasts and investigate the mechanism of action of ASCs. We further reported that ASC-EVs are more effective than parental cells suggesting that the TGFβ1-induced pro-fibrotic environment may alter the function of ASCs. [ABSTRACT FROM AUTHOR]

The incidence of rheumatic diseases such as rheumatoid arthritis and osteoarthritis and injuries to articular cartilage that lead to osteochondral defects is predicted to rise as a result of population ageing and the increase in high-intensity physical activities among young and middle-aged people. Current treatments focus on the management of pain and joint functionality to improve the patient's quality of life, but curative strategies are greatly desired. In the past two decades, the therapeutic value of mesenchymal stromal cells (MSCs) has been evaluated because of their regenerative potential, which is mainly attributed to the secretion of paracrine factors. Many of these factors are enclosed in extracellular vesicles (EVs) that reproduce the main functions of parental cells. MSC-derived EVs have anti-inflammatory, anti-apoptotic as well as pro-regenerative activities. Research on EVs has gained considerable attention as they are a potential cell-free therapy with lower immunogenicity and easier management than whole cells. MSC-derived EVs can rescue the pathogenetic phenotypes of chondrocytes and exert a protective effect in animal models of rheumatic disease. To facilitate the therapeutic use of EVs, appropriate cell sources for the production of EVs with the desired biological effects in each disease should be identified. Production and isolation of EVs should be optimized, and pre-isolation and post-isolation modifications should be considered to maximize the disease-modifying potential of the EVs. Extracellular vesicles derived from mesenchymal stromal cells provide the therapeutic benefits of the parental cells with advantages relating to immunogenicity and ease of handling. This Review discusses the therapeutic potential of native and modified extracellular vesicles for the treatment of rheumatic diseases, focusing on osteoarthritis and rheumatoid arthritis. Key points: Extracellular vesicles (EVs) have important roles in intercellular communication and convey many components at their surface or in their cargo that reproduce the functions of parental cells. Mesenchymal stromal cell (MSC)-derived EVs can regulate and prevent symptoms in non-clinical models of osteoarthritis and rheumatoid arthritis, notably by targeting local and systemic inflammation, and restoring a healthy chondrocyte phenotype. Improvement of isolation yields of MSC-EVs and functionality optimization by pre-isolation or post-isolation engineering are still required. Clinical translation of MSC-EVs for treatment of rheumatic diseases is ongoing, suggesting future potential for the treatment of these painful and disabling diseases. [ABSTRACT FROM AUTHOR]

Background: Articular cartilage (AC)'s main function is to resist to a stressful mechanical environment, and chondrocytes are responding to mechanical stress for the development and homeostasis of this tissue. However, current knowledge on processes involved in response to mechanical stimulation is still limited. These mechanisms are commonly investigated in engineered cartilage models where the chondrocytes are included in an exogeneous biomaterial different from their natural extracellular matrix. The aim of the present study is to better understand the impact of mechanical stimulation on mesenchymal stromal cells (MSCs)-derived chondrocytes generated in their own extracellular matrix. Methods: A fluidic custom-made device was used for the mechanical stimulation of cartilage micropellets obtained from human MSCs by culture in a chondrogenic medium for 21 days. Six micropellets were positioned into the conical wells of the device chamber and stimulated with different signals of positive pressure (amplitude, frequency and duration). A camera was used to record the sinking of each micropellet into their cone, and micropellet deformation was analyzed using a finite element model. Micropellets were harvested at different time points after stimulation for RT-qPCR and histology analysis. Results: Moderate micropellet deformation was observed during stimulation with square pressure signals as mean von Mises strains between 6.39 and 14.35% were estimated for amplitudes of 1.75–14 kPa superimposed on a base pressure of 50% of the amplitude. The compression, tension and shear observed during deformation did not alter micropellet microstructure as shown by histological staining. A rapid and transient increase in the expression of chondrocyte markers (SOX9, AGG and COL2B) was measured after a single 30-min stimulation with a square pressure signal of 3.5 kPa amplitude superimposed on a minimum pressure of 1.75 kPa, at 1 Hz. A small change of 1% of cyclical deformations when using a square pressure signal instead of a constant pressure signal induced a fold change of 2 to 3 of chondrogenic gene expression. Moreover, the expression of fibrocartilage (COL I) or hypertrophic cartilage (COL X, MMP13 and ADAMTS5) was not significantly regulated, except for COL X. Conclusions: Our data demonstrate that the dynamic deformation of cartilage micropellets by fluidic-based compression modulates the expression of chondrocyte genes responsible for the production of a cartilage-like extracellular matrix. This lays the foundations for further investigating the chondrocyte mechanobiology and the cartilage growth under mechanical stimulation. [ABSTRACT FROM AUTHOR]

Recent advances in cell reprogramming showed that OSKM induction is able to improve cell physiology in vitro and in vivo. Here, we show that a single short reprogramming induction is sufficient to prevent musculoskeletal functions deterioration of mice, when applied in early life. In addition, in old age, treated mice have improved tissue structures in kidney, spleen, skin, and lung, with an increased lifespan of 15% associated with organ‐specific differential age‐related DNA methylation signatures rejuvenated by the treatment. Altogether, our results indicate that a single short reprogramming early in life might initiate and propagate an epigenetically related mechanism to promote a healthy lifespan. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article titled "Extracellular vesicles from senescent mesenchymal stromal cells are defective and cannot prevent osteoarthritis" published in the Journal of Nanobiotechnology. The correction addresses an error in the original article where the names of the authors were incorrectly structured. The correct names of the authors are Jérémy Boulestreau, Marie Maumus, Giuliana M. Bertolino, Karine Toupet, Christian Jorgensen, and Danièle Noël. The correction has been made to the original article. Springer Nature, the publisher, remains neutral regarding jurisdictional claims and institutional affiliations. [Extracted from the article]

This correction notice is for an article titled "Therapeutic potential in rheumatic diseases of extracellular vesicles derived from mesenchymal stromal cells" published in Nature Reviews Rheumatology. The correction addresses an error in the final sentence of the "Role of MSC-EVs in FLS in RA" section. The corrected sentence now states that the data argue for an immunosuppressive and pro-apoptotic function of MSC-EV cargoes on RA synoviocytes, rather than a pro-survival function. The authors of the article are Giuliana Minani Bertolino, Marie Maumus, Christian Jorgensen, and Danièle Noël. [Extracted from the article]

Primary Sjögren's syndrome (pSS) can be associated with neurological and cognitive involvement, negatively affecting patients' quality of life. The aim of this study was to assess whether pSS patients are at higher risk of hospitalization for neurological diseases. Through a nationwide retrospective study using the French Health insurance database (based on International Classification for Disease codes, ICD-10), we selected patients hospitalized with new-onset pSS between 2011 and 2018. We compared the incidence of hospitalization for dementia, multiple sclerosis (MS), encephalitis, and peripheral neuropathy with an age- and sex-matched (1:10) hospitalized control group. Adjusted Hazard Ratios (aHR) considered confounding factors, particularly socio-economic status and cardiovascular diseases. We analyzed 25,661 patients hospitalized for pSS, compared with 252,543 matched patients. The incidence of hospitalization for dementia was significantly higher in pSS patients (aHR = 1.27 (1.04–1.55); p = 0.018), as well as the incidence of hospitalization for MS, encephalitis, and inflammatory polyneuropathies (aHR = 3.66 (2.35–5.68), p < 0.001; aHR = 2.66 (1.22–5.80), p = 0.014; and aHR = 23.2 (12.2–44.5), p < 0.001, respectively). According to ICD-10 codes, pSS patients exhibited a higher incidence of hospitalization for dementia, encephalitis, MS, and peripheral neuropathies than controls. Physicians must be aware of these neurological risks to choose the most appropriate diagnostic work-up. [ABSTRACT FROM AUTHOR]

• La sénescence cellulaire est devenue une nouvelle cible thérapeutique pour les maladies dégénératives liées à l'âge. • L'élimination des cellules sénescentes protège contre la dégradation du cartilage dans des modèles non cliniques d'arthrose. • Plusieurs molécules sénolytiques, qui ciblent les cellules sénescentes, sont en cours d'évaluation dans l'arthrose. • Les sénothérapies cellulaires, basées sur les cellules souches mésenchymateuses ou les vésicules extracellulaires qu'elles secrètent, ouvrent des perspectives pour le traitement de l'arthrose. La sénescence cellulaire est maintenant reconnue comme un mécanisme fondamental du vieillissement et l'élimination des cellules sénescentes est devenue une nouvelle cible thérapeutique pour les maladies dégénératives liées à l'âge, notamment dans l'arthrose. De nouvelles stratégies thérapeutiques qui visent à éliminer les cellules sénescentes ou sénothérapies se sont développées ces dernières années. Un certain nombre de cibles et de molécules thérapeutiques ont été identifiées et sont en cours d'évaluation en phases précliniques ou cliniques. Cette revue a pour objectif de faire le point sur l'avancée des traitements médicamenteux, cellulaires et acellulaires qui pourraient contribuer à retarder ou limiter la progression de l'arthrose. Cellular senescence has emerged as a fundamental mechanism of aging and neutralization of senescent cells has attracted much attention as a new therapeutic target for age-related diseases, including osteoarthritis. Novel therapeutic strategies that aim at eliminating senescent cells, called senotherapies, have been launched during the past few years. A number of therapeutic targets and drugs have been identified and are being evaluated in pre-clinical and clinical phases. Here, we review the growing field of senotherapies, including senolytics, cellular and acellular therapies that could contribute to delay or limit osteoarthritis progression. [ABSTRACT FROM AUTHOR]

Background: Mesenchymal stem cells (MSCs) have been recognized for their regenerative and anti-inflammatory capacity which makes them very attractive to cell therapy, especially those ones to treat inflammatory and autoimmune disease. Two different immune-phenotypes have been described for MSCs depending on which Toll-like receptor (TLR) is activated. MSC1 is endowed with a pro-inflammatory phenotype following TLR4 activation with LPS. On the other hand, anti-inflammatory MSC2 is induced by the activation of TLR3 with Poly(I:C). High immunoplasticity of MSCs is a matter of concern in cell-based therapies. In this study, we investigated whether a single stimulus can induce both types of MSCs through a differential activation of TLR4 with LPS. Methods: MSCs were activated with LPS following a short exposure of 1-h (MSCs-LPS1h) or long-time exposure for 48 h (MSCs-LPS48h), and then, we evaluated the biological response in vitro, the immunosuppressive capacity of MSCs in vitro, and the therapeutic potential of MSCs in an experimental autoimmune encephalomyelitis (EAE) mouse model. Results: Our results showed that 1-h LPS exposure induced a MSC1 phenotype. Indeed, MSCs-LPS1h expressed low levels of NO/iNOS and decreased immunosuppressive capacity in vitro without therapeutic effect in the EAE model. In contrast, MSCs-LPS48h achieved a MSC2-like phenotype with significant increase in the immunosuppressive capacity on T cell proliferation in vitro, together with an improved in the therapeutic effect and higher Treg, compared to unstimulated MSCs. Furthermore, we determine through the MSCs-TLR4KO that the expression of TLR4 receptor is essential for MSCs’ suppressive activity since TLR4 deletion was associated with a diminished suppressive effect in vitro and a loss of therapeutic effect in vivo. Conclusions: We demonstrate that MSCs display a high immunoplasticity commanded by a single stimulus, where LPS exposure time regulated the MSC suppressive effect leading into either an enhanced or an impairment therapeutic activity. Our results underscore the importance of phenotype conversion probably related to the TLR4 expression and activation, in the design of future clinical protocols to treat patients with inflammatory and autoimmune diseases. [ABSTRACT FROM AUTHOR]