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Osteoclasts, macrophages and dendritic cells (DCs) can be derived from a common trilineage myeloid progenitor of hematopoietic origin. Progenitor commitment is susceptible to regulation through Notch signaling. Our aim was to determine the effects of Notch modulation on trilineage progenitor commitment and functional properties of differentiated cells under inflammatory conditions. We used the conditional inducible CX3CR1CreERT2 mouse strain to achieve overexpression of the Notch 1 intracellular domain (NICD1) or to inhibit Notch signaling via deletion of the transcription factor RBP-J in a bone marrow population, used as a source of the trilineage progenitor (CD45+Ly6G-CD3-B220-NK1.1-CD11b-/loCD115+). Cre-recombinase, under the control of the CX3CR1 promoter, expressed in the monocyte/macrophage lineage, was induced in vitro by 4-hydroxytamoxifen. Differentiation of osteoclasts was induced by M-CSF/RANKL; macrophages by M-CSF; DCs by IL-4/GM-CSF, and inflammation by LPS. Functionally, DCs were tested for the ability to process and present antigen, macrophages to phagocytose E. coli particles, and osteoclasts to resorb bone and express tartrate-resistant acid phosphatase (TRAP). We found that Notch 1 signal activation suppressed osteoclast formation, whereas disruption of the Notch canonical pathway enhanced osteoclastogenesis, resulting in a higher number and size of osteoclasts. RANK protein and Ctsk gene expression were upregulated in osteoclastogenic cultures from RBP-J+ mice, with the opposing results in NICD1+ mice. Notch modulation did not affect the number of in vitro differentiated macrophages and DCs. However, RBP-J deletion stimulated Il12b and Cd86 expression in macrophages and DCs, respectively. Functional assays under inflammatory conditions confirmed that Notch silencing amplifies TRAP expression by osteoclasts, whereas the enhanced phagocytosis by macrophages was observed in both NICD1+ and RBP-J+ strains. Finally, antigen presentation by LPS-stimulated DCs was significantly downregulated with NICD1 overexpression. This experimental setting allowed us to define a cell-autonomous response to Notch signaling at the trilineage progenitor stage. Although Notch signaling modulation affected the activity of all three lineages, the major effect was observed in osteoclasts, resulting in enhanced differentiation and function with inhibition of canonical Notch signaling. Our results indicate that Notch signaling participates as the negative regulator of osteoclast activity during inflammation, which may be relevant in immune and bone diseases.
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Fator Estimulador de Colônias de Macrófagos , Osteogênese , Receptores Notch , Animais , Escherichia coli , Inflamação , Lipopolissacarídeos , Fator Estimulador de Colônias de Macrófagos/farmacologia , Macrófagos/citologia , Camundongos , Osteoclastos/citologia , Transdução de SinaisRESUMO
The available treatments for cholestatic liver fibrosis are limited, and the disease often progresses to liver cirrhosis. Tamoxifen is a selective modulator of estrogen receptors, commonly used in breast cancer therapy. A recent in vitro study showed that tamoxifen deactivates hepatic stellate cells, suggesting its potential as an antifibrotic therapeutic, but its effects in vivo remain poorly investigated. In the present study, we show that tamoxifen protects against the cholestatic fibrosis induced by a diet supplemented with 0.025% 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC). Mice fed with a DDC-supplemented diet for four weeks and treated with tamoxifen developed a significantly milder degree of liver fibrosis than vehicle-treated mice, as evidenced by a lower percentage of Sirius red-stained area (60.4% decrease in stained area in male and 42% decrease in female mice, p < 0.001 and p < 0.01, respectively) and by lower hydroxyproline content. The finding was further confirmed by qPCR analysis, which showed a lower expression of genes for Col1a1, Acta2, Sox9, Pdgf, and Krt19, indicating the inhibitory effect on hepatic stellate cells, collagen production, and biliary duct proliferation. The degree of protection was similar in male and female mice. Tamoxifen per se, injected into standard-diet-fed mice, increased the expression of genes for Il6 (p < 0.01 and p < 0.001 in male and female mice, respectively) and Tgfß (p < 0.01 for both sexes), and had no adverse effects. We showed that tamoxifen sex-independently protects against cholestatic DDC-induced liver fibrosis. The increased expression of Il6 and Tgfß seems to be a plausible protective mechanism that should be the primary focus of further research.
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Introduction: The existence of different osteoclast progenitor (OCP) subsets has been confirmed by numerous studies. However, pathological inflammation-induced osteoclastogenesis remains incompletely understood. Detailed characterization of OCP subsets may elucidate the pathophysiology of increased osteoclast activity causing periarticular and systemic bone resorption in arthritis. In our study, we rely on previously defined OCP subsets categorized by the level of CCR2 expression as circulatory-like committed CCR2hi OCPs, which are substantially expanded in arthritis, and marrow-resident CCR2lo OCPs of immature phenotype and behavior. Methods: In order to perform transcriptome characterization of those subsets in the context of collagen-induced arthritis (CIA), we sorted CCR2hi and CCR2lo periarticular bone marrow OCPs of control and arthritic mice, and performed next-generation RNA sequencing (n=4 for each group) to evaluate the differential gene expression profile using gene set enrichment analysis with further validation. Results: A disparity between CCR2hi and CCR2lo subset transcriptomes (863 genes) was detected, with the enrichment of pathways for osteoclast differentiation, chemokine and NOD-like receptor signaling in the CCR2hi OCP subset, and ribosome biogenesis in eukaryotes and ribosome pathways in the CCR2lo OCP subset. The effect of intervention (CIA) within each subset was greater in CCR2hi (92 genes) than in CCR2lo (43 genes) OCPs. Genes associated with the osteoclastogenic pathway (Fcgr1, Socs3), and several genes involved in cell adhesion and migration (F11r, Cd38, Lrg1) identified the CCR2hi subset and distinguish CIA from control group, as validated by qPCR (n=6 for control mice, n=9 for CIA mice). The latter gene set showed a significant positive correlation with arthritis clinical score and frequency of CCR2hi OCPs. Protein-level validation by flow cytometry showed increased proportion of OCPs expressing F11r/CD321, CD38 and Lrg1 in CIA, indicating that they could be used as disease markers. Moreover, osteoclast pathway-identifying genes remained similarly expressed (Fcgr1) or even induced by several fold (Socs3) in preosteoclasts differentiated in vitro from CIA mice compared to pre-cultured levels, suggesting their importance for enhanced osteoclastogenesis of the CCR2hi OCPs in arthritis. Conclusion: Our approach detected differentially expressed genes that could identify distinct subset of OCPs associated with arthritis as well as indicate possible therapeutic targets aimed to modulate osteoclast activity.
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Artrite Experimental , Reabsorção Óssea , Osteoclastos , Animais , Camundongos , Artrite Experimental/genética , Artrite Experimental/metabolismo , Artrite Experimental/patologia , Reabsorção Óssea/genética , Reabsorção Óssea/metabolismo , Reabsorção Óssea/patologia , Diferenciação Celular/genética , Diferenciação Celular/fisiologia , Perfilação da Expressão Gênica , Osteoclastos/metabolismo , Receptores CCR2/genética , Receptores CCR2/metabolismoRESUMO
Detailed characterization of medullary and extramedullary reservoirs of osteoclast progenitors (OCPs) is required to understand the pathophysiology of increased periarticular and systemic bone resorption in arthritis. In this study, we focused on identifying the OCP population specifically induced by arthritis and the role of circulatory OCPs in inflammatory bone loss. In addition, we determined the relevant chemokine axis responsible for their migration, and targeted the attraction signal to reduce bone resorption in murine collagen-induced arthritis (CIA). OCPs were expanded in periarticular as well as circulatory compartment of arthritic mice, particularly the CCR2hi subset. This subset demonstrated enhanced osteoclastogenic activity in arthritis, whereas its migratory potential was susceptible to CCR2 blockade in vitro. Intravascular compartment of the periarticular area contained increased frequency of OCPs with the ability to home to the arthritic bone, as demonstrated in vivo by intravascular staining and adoptive transfer of splenic LysMcre/Ai9 tdTomato-expressing cells. Simultaneously, CCL2 levels were increased locally and systemically in arthritic mice. Mouse cohorts were treated with the small-molecule inhibitor (SMI) of CCR2 alone or in combination with methotrexate (MTX). Preventive CCR2/CCL2 axis blockade in vivo reduced bone resorption and OCP frequency, whereas combining with MTX treatment also decreased disease clinical score, number of active osteoclasts, and OCP differentiation potential. In conclusion, our study characterized the functional properties of two distinct OCP subsets in CIA, based on their CCR2 expression levels, implying that the CCR2hi circulatory-like subset is specifically induced by arthritis. Signaling through the CCL2/CCR2 axis contributes to OCP homing in the inflamed joints and to their increased osteoclastogenic potential. Therefore, addition of CCL2/CCR2 blockade early in the course of arthritis is a promising approach to reduce bone pathology.
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Artrite Experimental/metabolismo , Artrite Reumatoide/metabolismo , Osso e Ossos/metabolismo , Quimiocina CCL2/metabolismo , Células-Tronco Mesenquimais/metabolismo , Osteoclastos/metabolismo , Receptores CCR2/metabolismo , Animais , Antirreumáticos/farmacologia , Artrite Experimental/tratamento farmacológico , Artrite Reumatoide/tratamento farmacológico , Benzoxazinas/farmacologia , Osso e Ossos/efeitos dos fármacos , Osso e Ossos/patologia , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/genética , Movimento Celular/efeitos dos fármacos , Movimento Celular/genética , Células Cultivadas , Modelos Animais de Doenças , Citometria de Fluxo , Humanos , Masculino , Células-Tronco Mesenquimais/citologia , Metotrexato/farmacologia , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Osteoclastos/citologia , Interferência de RNA , Receptores CCR2/antagonistas & inibidores , Receptores CCR2/genética , Compostos de Espiro/farmacologiaRESUMO
Alcoholic liver cirrhosis (ALC) is the most common indication for liver transplantation (LT) in Croatia and presents a risk factor for the development of hepatocellular carcinoma (HCC). However, genetic susceptibility has not yet been systematically studied. We aimed to investigate the contribution of the risk polymorphisms PNPLA3 rs738409, EGF rs4444903, TM6SF2 rs58542926, MTHFR rs1801133, previously identified in other populations and, additionally, the contribution of Notch-related polymorphisms (NOTCH1 rs3124591, NOTCH3 rs1043996 and rs1044116, NOTCH4 rs422951). The study included 401 patients. The ALC group consisted of 260 LT candidates, 128 of whom had histopathologically confirmed HCC, and 132 of whom were without HCC. The control group included 141 patients without liver disease. Genotyping was performed by PCR using Taqman assays. The patients' susceptibility to ALC was significantly associated with PNPLA3 rs738409, TM6SF2 rs58542926, and NOTCH3 rs1043996 polymorphisms. These polymorphisms remained significantly associated with ALC occurrence in a logistic regression model, even after additional model adjustment for sex and age. Cirrhotic patients with the PNPLA3 GG genotype demonstrated higher activity of ALT aminotransferases than patients with CC or CG genotypes. The susceptibility to the development of HCC in ALC was significantly associated with PNPLA3 rs738409 and EGF rs4444903 polymorphisms, and logistic regression confirmed these polymorphisms as independent predictors.
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BACKGROUND: Notch pathway is highly conserved across species and is involved in the regulation of cell differentiation and activity both in embryonic development and adult life. Notch signaling has an important role in the development of hematopoietic stem cells and their differentiation to committed lineages, as well as in the regulation of several non-hematopoietic cell lines. OBJECTIVE: As Notch signaling has been implicated in various inflammatory and autoimmune diseases, it is of interest to elucidate what role do Notch receptors and ligands have in inflammatory arthritides. METHODS: We performed a search on the role of Notch receptors (1-4) and Notch ligands Delta-like (DLL) 1, 3, 4 and Jagged (Jag) 1 and 2 in animal models of inflammatory arthritis and most common types of human inflammatory arthritis (rheumatoid arthritis, psoriatic arthritis or ankylosing spondylitis). The initial search identified 135 unique articles, of which 24 were ultimately deemed relevant and included in this systematic review. RESULTS: Overall, identified articles describe roles for Notch ligands and receptors in inflammatory arthritis, with Notch activation resulting in enhanced Th1/17 polarization, osteoclast differentiation, macrophage activation and fibroblast-like synoviocyte proliferation. However, the inhibitory role of Notch signaling, especially by Jag1 is also described. CONCLUSION: There is evidence that Notch pathway activation affects multiple cell lineages present within the arthritic environment, therefore potentially acting as one of the drivers of disease pathogenesis. Since cell lineage-selective transgenic mouse models and specific Notch receptor inhibitors are becoming increasingly available, it can be expected that future research will evaluate whether Notch signaling components initiate crucial pathogenic impulses and, therefore, present viable therapeutic targets in inflammatory arthritis.
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Artrite/metabolismo , Inflamação/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas de Membrana/metabolismo , Osteoclastos/fisiologia , Receptores Notch/metabolismo , Proteínas Serrate-Jagged/metabolismo , Células Th1/imunologia , Células Th17/imunologia , Animais , Diferenciação Celular , Modelos Animais de Doenças , HumanosRESUMO
Although, liver transplantation serves as the only curative treatment for patients with end-stage liver diseases, it is burdened with complications, which affect survival rates. In addition to clinical risk factors, contribution of recipient and donor genetic prognostic markers has been extensively studied in order to reduce the burden and improve the outcomes. Determination of single nucleotide polymorphisms (SNPs) is one of the most important tools in development of personalized transplant approach. To provide a better insight in recent developments, we review the studies published in the last three years that investigated an association of recipient or donor SNPs with most common issues in liver transplantation: Acute cellular rejection, development of new-onset diabetes mellitus and non-alcoholic fatty liver disease, hepatocellular carcinoma recurrence, and tacrolimus concentration variability. Reviewed studies confirmed previously established SNP prognostic factors, such as PNPLA3 rs738409 for non-alcoholic fatty liver disease development, or the role of CYP3A5 rs776746 in tacrolimus concentration variability. They also identified several novel SNPs, with a reasonably strong association, which have the potential to become useful predictors of post-transplant complications. However, as the studies were typically conducted in one center on relatively low-to-moderate number of patients, verification of the results in other centers is warranted to resolve these limitations. Furthermore, of 29 reviewed studies, 28 used gene candidate approach and only one implemented a genome wide association approach. Genome wide association multicentric studies are needed to facilitate the development of personalized transplant medicine.
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Doença Hepática Terminal/genética , Rejeição de Enxerto/genética , Transplante de Fígado/efeitos adversos , Polimorfismo de Nucleotídeo Único , Complicações Pós-Operatórias/genética , Citocromo P-450 CYP3A/genética , Doença Hepática Terminal/cirurgia , Feminino , Humanos , Imunossupressores/sangue , Lipase/genética , Masculino , Proteínas de Membrana/genética , Prognóstico , Tacrolimo/sangue , Resultado do TratamentoRESUMO
AIM: To investigate the association of FasL gene polymorphism (rs763110) with rheumatoid arthritis occurrence, disease activity, and tumor necrosis factor-α (TNF-α) plasma concentration in Croatian patients, and to conduct an updated meta-analysis. METHODS: This cross-sectional study enrolled 81 patients with rheumatoid arthritis and 94 control patients. After the assessment of the Disease Activity Score (DAS)-28, blood was taken for analysis. DNA was isolated from the whole blood to determine FasL polymorphism (rs763110) by polymerase chain reaction. Protein levels of TNF-α were determined with ELISA. After a detailed literature search, we conducted an updated meta-analysis using the Review Manager 5 software. RESULTS: Rheumatoid arthritis patients had significantly higher TNF-α concentration in plasma (1.65 [1.2-2.42] pg/mL) than controls (0.99 [0.77-1.35] pg/mL, P<0.001). The FasL rs763110 polymorphism was not associated with rheumatoid arthritis occurrence in either codominant, dominant, recessive, overdominant, or log additive model. Furthermore, the rs763110 genotype was not associated with DAS 28 score or TNF-α concentration. After we added our results to an updated meta-analysis, the significant association previously reported for Western Eurasians was abolished. CONCLUSION: Our data suggest that the association between FasL rs763110 polymorphism and RA susceptibility in Western Eurasians observed in previous studies might be overestimated and should be limited to the population of Southwestern Asia until further investigations are performed.