Scleroderma is an autoimmune disease that causes dermal fibrosis. It occurs when collagen accumulates in tissue as a result of persistent inflammation. Th17 cells and pro-inflammatory cytokines such ...as IL-1β, IL-6, IL-17, and TNF-α play important roles in the pathogenesis of scleroderma. Because metformin, a medication used to treat diabetes, has effective immunoregulatory functions, we investigated its therapeutic function in scleroderma. Mice in a model of bleomycin-induced scleroderma were treated with metformin for 2 weeks. Histological assessment demonstrated protective effects of metformin against scleroderma. Metformin decreased the expression of pro-inflammatory factors in dermal tissue and lymphocytes. It also decreased mRNA expression of pro-inflammatory cytokines (IL-1β, IL-6, IL-17, and TNF-α) and fibrosis-inducing molecules both in vivo and in vitro. These results suggest that metformin treatment has anti-inflammatory effects on lymphocytes via the inhibition of IL-17 and cytokines related to Th17 differentiation, such as IL-1β, IL-6, and TNF-α. To investigate how metformin modulates the inflammatory process in skin fibroblasts, we measured mTOR-STAT3 signaling in skin fibroblasts and found that phosphorylated mTOR and phosphorylated STAT3 protein expression were decreased by metformin treatment. These results suggest that metformin has potential to treat scleroderma by inhibiting pro-inflammatory cytokines and anti-inflammatory activity mediated by mTOR-STAT3 signaling.
Concentration is critical: Amine/isocyanate polycondensation below the critical gelation concentration cg affords a sol of growing microporous molecular‐network nanoparticles rather than a gelated ...network (see picture, for model of particle: NCO red, NH2 blue, tetrahedral cross‐link point gray). Further growth to form monolithic networks occurs on solvent evaporation, analogous to sol–gel synthesis of inorganic oxide networks.
Mesenchymal stem cells (MSCs) can protect against cartilage breakdown in osteoarthritis (OA) via their immunomodulatory capacities. However, the optimization strategy for using MSCs remains ...challenging. This study's objective was to identify the in vivo effects of metformin-stimulated adipose tissue-derived human MSCs (Ad-hMSCs) in OA. An animal model of OA was established by intra-articular injection of monosodium iodoacetate into rats. OA rats were divided into a control group and two therapy groups (treated with Ad-hMSCs or metformin-stimulated Ad-hMSCs). Limb nociception was assessed by measuring the paw withdrawal latency and threshold. Our data show that metformin increased IL-10 and IDO expression in Ad-hMSCs and decreased high-mobility group box 1 protein, IL-1β, and IL-6 expression. Metformin increased the migration capacity of Ad-hMSCs with upregulation of chemokine expression. In cocultures, metformin-stimulated Ad-hMSCs inhibited the mRNA expression of RUNX2, COL X, VEGF, MMP1, MMP3, and MMP13 in IL-1β-stimulated OA chondrocytes and increased the expression of TIMP1 and TIMP3. The antinociceptive activity and chondroprotective effects were greater in OA rats treated with metformin-stimulated Ad-hMSCs than in those treated with unstimulated Ad-hMSCs. TGF-β expression in subchondral bone of OA joints was attenuated more in OA rats treated with metformin-stimulated Ad-hMSCs. Our findings suggest that metformin offers a promising option for the clinical application of Ad-hMSCs as a cell therapy for OA.
Objective
Dual‐specificity phosphatase 5 (DUSP‐5) is a phosphatase that specifically dephosphorylates both phosphoserine and phosphotyrosine residues of MAPK. The dysregulated activation of MAPK ...contributes to the pathogenesis of rheumatoid arthritis. This study was undertaken to investigate the therapeutic potential of DUSP‐5 in preventing the development of autoimmune arthritis in an animal model.
Methods
Autoimmune arthritis was induced in DBA/1J mice by immunization with type II collagen (CII). Eight days after CII immunization, the mice were injected intravenously with pcDNA–DUSP5 or mock vector, and electroporation was performed. The serum concentration of anti‐CII antibodies was measured by enzyme‐linked immunosorbent assay. Histologic analysis of the joints was performed using Safranin O, toluidine blue, and immunohistochemical staining. The expression of transcription factors was analyzed by immunostaining and Western blotting. The frequencies of interleukin‐17–producing CD4+ Th17 cells and CD4+CD25+Foxp3+ Treg cells were analyzed by flow cytometry.
Results
In DUSP5‐overexpressing mice, the severity of arthritis, as indicated by the clinical arthritis score and the extent of histologic inflammation and cartilage damage, was attenuated. The pcDNA–DUSP5–injected mice had lower circulating levels of total and CII‐specific IgG, IgG1, and IgG2a. The Th17 cell population frequency was decreased and the Treg cell frequency was increased in the spleens of the DUSP5‐treated group. The reciprocal regulation of Th17 and Treg cells in vivo was associated with attenuated activity of pSTAT‐3 and pERK, and with increased activity of pSTAT‐5. DUSP5 overexpression suppressed joint damage through down‐regulation of pro‐osteoclastogenic molecules.
Conclusion
The antiarthritic properties of DUSP‐5 are associated with its reciprocal regulation of Th17 and Treg cells and its inhibition of ERK activity.
Circulating autoantibodies and immune complex deposition are pathological hallmarks of systemic lupus erythematosus (SLE). B cell differentiation into plasma cells (PCs) and some T cell subsets that ...function as B cell helpers can be therapeutic targets of SLE. Mechanistic target of rapamycin (mTOR) signaling is implicated in the formation of B cells and germinal centers (GCs). We assessed the effect of metformin, which inhibits mTOR, on the development of autoimmunity using Roquinsan/san mice. Oral administration of metformin inhibited the formation of splenic follicles and inflammation in kidney and liver tissues. It also decreased serum levels of anti-dsDNA Abs without affecting serum glucose levels. Moreover, metformin inhibited CD21highCD23low marginal zone B cells, B220+GL7+ GC B cells, B220-CD138+ PCs, and GC formation. A significant reduction in ICOS+ follicular helper T cells was found in the spleens of the metformin-treated group compared with the vehicle-treated group. In addition, metformin inhibited Th17 cells and induced regulatory T cells. These alterations in B and T cell subsets by metformin were associated with enhanced AMPK expression and inhibition of mTOR-STAT3 signaling. Furthermore, metformin induced p53 and NF erythroid-2-related factor-2 activity in splenic CD4+ T cells. Taken together, metformin-induced alterations in AMPK-mTOR-STAT3 signaling may have therapeutic value in SLE by inhibiting B cell differentiation into PCs and GCs.
Thermal densification in asymmetric hollow fibers fabricated using thermally rearranged (TR) polymers has been regarded as a challenging issue due to productivity reduction by severe permeance loss. ...However, it has recently been reported from our group that the densification phenomenon could be exploited to induce ultrathin skin layer from highly porous precursor fibers. We successfully prepared densification-induced crosslinked thermally rearranged (diXTR) fibers from porous XHPI precursor fibers. The proposed hollow fiber fabrication method using the XTR material effectively enhanced CO2 permeance by 2-fold, without any loss of CO2/N2 selectivity, compared to a traditional method. Extending from our previous work, in this study it was found that the densification during TR process can be dimensionally restricted in order to maximize the gas permeance. Generally, the thermal densification induces omnidirectional shrinkage of heat treated fibers above Tg. The longitudinal shrinkage can be prevented by physically holding both ends of hollow fibers during thermal treatment. This approach was applied to diXTR hollow fibers, which allowed a remarkable CO2 permeance exhibiting around 4,600 GPU with 18 CO2/N2 selectivity. It was discovered that an effective suppression of the thermal densification occurred at the vicinity of Tg. A skin layer thickness of 52 nm was achieved (calculated using O2 permeance). Evaluation of mechanical properties resulted in no evidence of mechanical weakness in dimensionally-controlled diXTR (2D-diXTR) fibers. Additionally, a direct methanol treatment was adopted to restore CO2 permeance of 30 day elapsed 2D-diXTR fiber modules. The method effectively recovered CO2 permeance up to 92% for an original permeance.
(a) Conceptual image of ‘conventional densification-induced’ XTR (3D-diXTR) fibers and ‘dimensionally-restricted’ 2D-diXTR fibers and (b) Comparison of CO2 permeance and CO2/N2 selectivity in 3D-diXTR and 2D-diXTR fibers at different TR temperature. Display omitted
•Densification-induced XTR hollow fibers were successfully fabricated.•Densification was quantified by cross-sectional and longitudinal shrinkage.•The longitudinal shrinkage was restricted during TR process.•Dimensionally controlled densification resulted in CO2 permeance of 4,590 GPU.•Mechanical and long-term stability were assessed for different diXTR fibers.
Objective
Rebamipide, a gastroprotective agent, has the ability to scavenge reactive oxygen radicals. Increased oxidative stress is implicated in the pathogenesis of rheumatoid arthritis (RA). We ...undertook this study to investigate the impact of rebamipide on the development of arthritis and the pathophysiologic mechanisms by which rebamipide attenuates arthritis severity in a murine model of RA.
Methods
Collagen‐induced arthritis (CIA) was induced in DBA/1J mice. Anti–type II collagen antibody titers and interleukin‐17 (IL‐17) levels were determined using enzyme‐linked immunosorbent assay. The expression of transcription factors was analyzed by immunostaining and Western blotting. Frequencies of IL‐17–producing CD4+ T cells (Th17 cells) and CD4+CD25+FoxP3+ Treg cells were analyzed by flow cytometry.
Results
Rebamipide reduced the clinical arthritis score and severity of histologic inflammation and cartilage destruction in a dose‐dependent manner. The joints isolated from rebamipide‐treated mice with CIA showed decreased expression of nitrotyrosine, an oxidative stress marker. Rebamipide‐treated mice showed lower circulating levels of type II collagen–specific IgG, IgG1, and IgG2a. Whereas the number of Th17 cells in spleens was decreased in rebamipide‐treated mice with CIA, a significant increase in the number of Treg cells in spleens was observed. In vitro, rebamipide inhibited Th17 cell differentiation through STAT‐3/retinoic acid receptor–related orphan nuclear receptor γt and reciprocally induced Treg cell differentiation through FoxP3. Rebamipide increased Nrf2 nuclear activities in murine CD4+ T cells and LBRM‐33 murine T lymphoma cells. Heme oxygenase 1 (HO‐1) expression in the spleens was markedly increased in rebamipide‐treated mice.
Conclusion
The inhibitory effects of rebamipide on joint inflammation are associated with recovery from an imbalance between Th17 cells and Treg cells and with activation of an Nrf2/HO‐1 antioxidant pathway.
Fibroblast-like synoviocytes (FLSs) are a major cell population of the pannus that invades cartilage and bone in rheumatoid arthritis (RA). FLS resistance to apoptosis is a major characteristic of ...RA. The aims of this study were to investigate the effects of interleukin-17 (IL-17) and IL-17-producing T helper (Th17) cells on resistance to apoptosis in FLSs from RA patients (RA FLSs) and their roles in mitochondrial dysfunction and autophagy. Mitochondrial function was assessed in RA FLSs and FLSs from osteoarthritis patients (OA FLSs). FLSs were treated with IL-17 and their morphological features, respiratory level and mitochondrial gene expression were measured. The effects of IL-17 and Th17 cells on the relationship between autophagy and apoptosis were evaluated by measuring the expression of apoptosis-related genes using sodium nitroprusside or 3-methyladenine. The mitochondria of FLSs isolated from RA and osteoarthritis patients displayed different morphological and physiological features. RA FLSs exhibited greater autophagosome formation and greater dysfunction of mitochondrial respiration compared with OA FLSs. IL-17 induced mitochondrial dysfunction and autophagosome formation in RA FLSs, suggesting that they were resistant to apoptosis. Autophagy-related antiapoptosis induced by IL-17 was restored by inhibition of autophagy, suggesting a relationship between mitochondrial dysfunction and cell survival in RA FLSs. Th17 cells and IL-17 increased autophagy of RA FLSs by causing mitochondrial dysfunction. Our findings suggest that, in RA, interactions between RA FLSs and Th17 cells may be involved in the tumorous growth of FLSs and the formation of pannus in joints.
Systemic sclerosis (SSc) is a progressive fibrotic disease that affects the skin and internal organs. Despite evidence implicating increased interleukin-17 (IL-17) activity in SSc, the role of IL-17 ...in SSc remains uncertain. The purpose of this study was to investigate whether IL-17 plays a pathophysiological role in SSc in two different murine models of SSc.
Bleomycin (BLM)-induced fibrosis and chronic graft-versus-host disease (cGVHD) models were used. Histological analysis was performed using Masson's trichrome and immunohistochemical staining. Quantitative reverse transcription-polymerase chain reaction and enzyme-linked immunoassays were used to quantify the messenger RNA and protein levels of inflammatory mediators in dermal fibroblasts.
IL-1 receptor antagonist-deficient (IL-1Ra-KO) mice were more severely affected by BLM injection, as shown by dermal and pulmonary fibrosis, compared with wild-type (WT) mice. Increased tissue fibrosis was reversed by knocking down IL-17.
experiments showed that IL-1 and IL-17 exerted synergistic effects on the expression of profibrotic and inflammatory mediators. In the cGVHD model, C57BL/6 mice receiving splenocytes of IL-1Ra-KO BALB/c mice developed more severe cGVHD than did those receiving cells from WT mice. Knockdown of IL-17 in IL-1Ra-KO donor mice significantly attenuated the IL-1-induced acceleration of cGVHD severity.
Targeting IL-1 and its downstream IL-17 activity may be a novel treatment strategy for inhibiting inflammation and tissue fibrosis in SSc.
The preparation of bicontinuous nanoporous covalent frameworks, which are promising for caging active enzymes, is demonstrated. The frameworks have three‐ dimensionally continuous, hydrophilic pores ...with widths varying between 5 and 30 nm. Enzymes were infiltrated into the bicontinuous pore by applying a pressured enzyme solution. The new materials and methods allowed the amount of caged proteins to be controlled precisely. The resulting enzyme‐loaded framework films could be recycled many times with nearly no loss of catalytic activity. Entropic trapping of proteins by a bicontinuous pore with the right size distribution is an unprecedented strategy toward facile in vitro utilization of biocatalysts.
In a gilded cage: A bicontinuous nanoporous framework was synthesized by simultaneous phase separation, gelation, and a grafting reaction of the sol mixture of a growing network and polymer. An enzyme caged in the bicontinuous nanoporous film could be recycled many times with nearly no loss of catalytic activity.
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