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Auxin is the reciprocal signaling molecule, which interferes with other phyto-hormonal and physiological processes during plant–microbes interaction. In this regard, Bipolaris spp., a growth-promoting endophytic fungus was used to inoculate pre-stressed Zea mays seedlings with yucasin (IAA inhibitor). The IAA-deficient host was heavily colonized by the endophyte that subsequently promoted the host growth and elevated the IAA levels with a peak value at 72 h. However, the seedling growth was inhibited later (i.e., at 120 h) due to the high levels of IAA that interfered with the activity of phytoalexins and brassinosteroids. Such interference also modulated the endophytic fungus from symbiotic to biotrophic pathogen that left the host plants defenseless.

Leaf angle and grain size are important agronomic traits affecting rice productivity directly and/or indirectly through modulating crop architecture. OsBC1, as a typical bHLH transcription factor, is one of the components comprising a complex formed with LO9-177 and OsBUL1 contributing to modulation of rice leaf inclination and grain size. In the current study, two homologues of OsBC1, OsBCL1 and OsBCL2 were functionally characterized by expressing them under the control of OsBUL1 promoter, which is preferentially expressed in the lamina joint and the spikelet of rice. Increased leaf angle and grain length with elongated cells in the lamina joint and the grain hull were observed in transgenic rice containing much greater gibberellin A3&nbsp, (GA3) levels than WT, demonstrating that both OsBCL1 and OsBCL2 are positive regulators of cell elongation at least partially through increased GA biosynthesis. Moreover, the cell elongation was likely due to cell expansion rather than cell division based on the related gene expression and, the cell elongation-promoting activities of OsBCL1 and OsBCL2 were functional in a dicot species, Arabidopsis.

Cowpea [Vigna unguiculata (L.) Walp] is a globally important food security crop. However, it is susceptible to pest and disease; hence, constant breeding efforts based on its diversity are required for its improvement. The present study aims to investigate the genetic diversity, population structure, and linkage disequilibrium (LD) among 274 cowpea accessions from different origins. A total of 3,127 single nucleotide polymorphism (SNP) markers generated using diversity array technology (DArT) was used. Population structure, neighbor‐joining clustering, and principal component analyses indicated three subpopulations within the germplasm. Results of STRUCTURE analysis and discriminant analysis of principal components (DAPC) were complementary in assessing the structuration of the diversity among the germplasm, with the grouping of the accessions improved in DAPC. Genetic distances of 0.005–0.44 were observed among accessions. Accessions from western and central Africa, eastern and central Africa, and Asia were predominant and distributed across all subpopulations. The subpopulations had fixation indexes of 0.48–0.56. Analysis of molecular variance revealed that within subpopulation variation accounted for 81% of observed genetic variation in the germplasm. The subpopulations mainly consisted of inbred lines (inbreeding coefficient = 1) with common alleles, although they were from different geographical regions. This reflects considerable seed movement and germplasm exchange between regions. The LD was characterized by low decay for great physical distances between markers. The LD decay distance varied among chromosomes with the average distance of 80–100 kb across the genome. Thus, crop improvement is possible, and the LD will facilitate genome‐wide association studies on quality attributes and critical agronomic traits in cowpea.

Background: Ginseng (Panax ginseng Meyer) is an essential source of pharmaceuticals and functional foods. Ginseng productivity has been compromised by high light (HL) stress, which is one of the major abiotic stresses during the ginseng cultivation period. The genetic improvement for HL tolerance in ginseng could be facilitated by analyzing its genetic and molecular characteristics associated with HL stress. Methods: Genome-wide analysis of gene expression was performed under HL and recovery conditions in 1-year-old Korean ginseng (P. ginseng cv. Chunpoong) using the Illumina HiSeq platform. After de novo assembly of transcripts, we performed expression profiling and identified differentially expressed genes (DEGs). Furthermore, putative functions of identified DEGs were explored using Gene Ontology terms and Kyoto Encyclopedia of Genes and Genome pathway enrichment analysis. Results: A total of 438 highly expressed DEGs in response to HL stress were identified and selected from 29,184 representative transcripts. Among the DEGs, 326 and 114 transcripts were upregulated and downregulated, respectively. Based on the functional analysis, most upregulated and a significant number of downregulated transcripts were related to stress responses and cellular metabolic processes, respectively. Conclusion: Transcriptome profiling could be a strategy to comprehensively elucidate the genetic and molecular mechanisms of HL tolerance and susceptibility. This study would provide a foundation for developing breeding and metabolic engineering strategies to improve the environmental stress tolerance of ginseng. Keywords: High light stress, Panax ginseng, Photoinhibition, Photoprotection, Transcriptome analysis

Plants are susceptible to various environmental constrains, including heat stress due to their sessile nature. Endophytic fungi can be used as a novel technique to protect crop plants against the injurious effects of thermal stress. Endophytic fungi were isolated from Adiantum capillus-veneris L. and tested against heat stress in Glycine max L. and Helianthus annuus L. The results exhibited increased levels of the plant’s chlorophyll, height and biomass in Aspergillus foetidus (AdR-13) inoculated host crop species. Conversely, a significant decrease in lipid peroxidation and reactive oxygen species (ROS) production was noted in A. foetidus-associated host crop species. Likewise, the amounts of ROS-degrading antioxidants (glutathione reductase (GR), peroxidase (POD), ascorbic acid oxidase (AAO), superoxide dismutase (SOD), catalase (CAT)) as well as phenolics were increased, while the amounts of proline and abscisic acid (ABA) were decreased in fungal-associated test crops. Total lipids, proteins and sugars were noted to be high in A. foetidus-associated test crops. From the results, we concluded that A. foetidus have a role in heat stress mitigation that might help to sustain the production of important crops in the future.

Frankincense tree (Boswellia sacra Fluek) has been poorly known on how it responds to tapping and wound-recovery process at molecular levels. Here, we used RNA-sequencing analysis to profile transcriptome of B. sacra after 30 min, 3 h and 6 h of post-tapping. Results showed 5525 differentially expressed genes (DEGs) that were related to terpenoid biosynthesis, phytohormonal regulation, cellular transport, and cell-wall synthesis. Plant-growth-regulators were applied exogenously which showed regulation of endogenous jasmonates and resulted in rapid recovery of cell-wall integrity by significantly up-regulated gene expression of terpenoid biosynthesis (germacrene-D synthase, B-amyrin synthase, and squalene epioxidase-1) and cell-wall synthesis (xyloglucan endotransglucosylase, cellulose synthase-A, and cell-wall hydrolase) compared to control. These findings suggest that tapping immediately activated several cell-developmental and regeneration processes, alongwith defense-induced terpenoid metabolism, to improve the healing process in epidermis. Exogenous growth regulators, especially jasmonic acid, can drastically help tree recovery from tissue degeneration and might help in tree conservation purposes.

Background: Genetic diversity in a germplasm is crucial for continuous improvement of crop varieties. A panel of 274 cowpea (Vigna unguiculata L.) accessions of unknown genetic diversity was assembled from diverse sources. This study used 3127 SNP markers, generated with the diversity array technology (DArT), to assess genetic diversity, population structure and linkage disequilibrium (LD) in the assembled germplasm.Results: The structure analysis inferred three subpopulations within the germplasm, which was confirmed by Neighbour-Joining (NJ) clustering and principal component analysis (PCA). Low genetic distances (0.005 to 0.44) were observed between accessions. Accessions from Africa; West and Central Africa (113 accessions), East and Central Africa (93 accessions), and Asia (53 accessions) were predominant in the germplasm; and distributed across all subpopulations. High fixation indexes (0.48 ≤ FST≤0.56) were obtained for the inferred subpopulations. AMOVA revealed a very large contribution (99%) of within subpopulations variation to the observed genetic variation in the germplasm. However, the expected heterozygosity (He) was higher than the observed heterozygosity (Ho), indicating high proportion of inbred lines in the germplasm. Linkage Disequilibrium (LD) was observed in the germplasm, particularly on chromosome 6, which showed a low decay along the physical genetic distance between markers in the genome.Conclusions: Significant genetic structuration exists in the assembled cowpea germplasm which shows there is a potential for improvement of the crop. The subgroups consisted mainly of inbred lines which, although from different geographical regions shared alleles in common reflecting high movement of seeds and exchange of germplasm between regions. The presence of linkage disequilibrium in the germplasm paves a way for prospective whole genome-wide association studies in cowpea for quality attributes and important agronomic traits.

Rootstock variety influences leaf metabolic profiles in a grafted citrus tree, but influence also depends on the scion. Proper selection of rootstocks in tree fruit crops such as citrus is important for successful production. Despite a large number of commercially available rootstocks, studies have mostly been limited to basic horticultural observations. We used untargeted gas chromatography-time of flight-mass spectrometry (GC-TOF MS) based metabolomics to understand the biochemical influence of rootstock on 2-year-old field-grown ‘Cara Cara’ navel orange (Citrus sinensis L. Osbeck) and ‘Hirado Buntan’ pummelo (C. grandis L. Osbeck) trees grown on four rootstock cultivars with different genetic background. Five hundred unique metabolites were quantified in all trees, of which 147 were chemically identified. In navel orange trees, 48 root metabolites differed significantly in concentrations among rootstocks, compared with 29 metabolites in pummelo trees. In navel orange trees, raffinose, conduritol beta-epoxide, allantoic acid, myo-inositol, gamma-tocopherol, and beta gentiobiose were among the compounds that contributed most to this variation. In pummelo trees, hexitol, allantoic acid, glucoheptulose, tryptophan, gamma-tocopherol, glycerol-3-galactoside, and raffinose were among the most discriminating metabolites, but only allantoic acid passed significance criteria. Rootstock was also found to influence the quantities of 226 metabolites in leaves of the navel orange scion. Conduritol-beta-epoxide and myo-inositol were among the metabolites most influenced by rootstock. In contrast, the influence of rootstock on the pummelo scion was less prominent, with only six metabolites displaying significant differences. Our findings demonstrate that rootstock variety can influence the metabolic profile of the leaves in a grafted tree, but that the extent of the effect is also influenced by the scion. The majority of root metabolites that discriminated most between rootstocks did not display the same rootstock-specific discrimination in the leaves, suggesting tissue specificity or limited movement across the graft union.

The effect of salt treatment on Brassica carinata (BC) microgreens grown under different light wavelengths on glucosinolates (GLs) and phenolic compounds were evaluated. Quantifiable GLs were identified using ultra-high performance-quadrupole time of flight mass spectrometry. Extracts’ ability to activate antioxidant enzymes (superoxide dismutase (SOD) and catalase (CAT)) was evaluated on human colorectal carcinoma cells (HCT116). Furthermore, BC compounds’ ability to activate expression of nuclear transcription factor-erythroid 2 related factor (Nrf2) and heme-oxygenase-1 (HO-1) proteins was examined using specific antibodies on HCT116 cells. Sinigrin (SIN) was the abundant GLs of the six compounds identified and its content together with total aliphatic GLs increased in saline conditions. Fluorescent (FL) and blue plus red (B1R1) lights were identified as stable cultivation conditions for microgreens, promoting biomass and glucobrassicin contents, whereas other identified individual and total indole GLs behaved differently in saline and non-saline environments. Blue light-emitting diodes and FL light in saline treatments mostly enhanced SIN, phenolics and antioxidant activities. The increased SOD and CAT activities render the BC microgreens suitable for lowering oxidative stress. Additionally, activation of Nrf2, and HO-1 protein expression by the GLs rich extracts, demonstrate their potential to treat and prevent oxidative stress and inflammatory disorders. Therefore, effective salt treatments and light exposure to BC microgreens present an opportunity for targeted regulation of growth and accumulation of bioactive metabolites.

Ganoderma lucidum extract is a potent traditional remedy for curing various ailments. Drying is the most important postharvest step during the processing of Ganoderma lucidum. The drying process mainly involves heat (36 h at 60 °C) and freeze-drying (36 h at −80 °C). We investigated the effects of different postharvest drying protocols on the metabolites profiling of Ganoderma lucidum using GC-MS, followed by an investigation of the anti-neuroinflammatory potential in LPS-treated BV2 microglial cells. A total of 109 primary metabolites were detected from heat and freeze-dried samples. Primary metabolite profiling showed higher levels of amino acids (17.4%) and monosaccharides (8.8%) in the heat-dried extracts, whereas high levels of organic acids (64.1%) were present in the freeze-dried samples. The enzymatic activity, such as ATP-citrate synthase, pyruvate kinase, glyceraldehyde-3-phosphatase dehydrogenase, glutamine synthase, fructose-bisphosphate aldolase, and D-3-phosphoglycerate dehydrogenase, related to the reverse tricarboxylic acid cycle were significantly high in the heat-dried samples. We also observed a decreased phosphorylation level of the MAP kinase (Erk1/2, p38, and JNK) and NF-κB subunit p65 in the heat-dried samples of the BV2 microglia cells. The current study suggests that heat drying improves the production of ganoderic acids by the upregulation of TCA-related pathways, which, in turn, gives a significant reduction in the inflammatory response of LPS-induced BV2 cells. This may be attributed to the inhibition of NF-κB and MAP kinase signaling pathways in cells treated with heat-dried extracts.

This study was aimed at investigating the therapeutic effects of BITRAP, a bispecific fusion protein targeting TNF-α and IL-21, on the development of autoimmune arthritis in humans and mice. To verify the effects of BITRAP in human, peripheral blood mononuclear cells were cultured with BITRAP under IL-17-producing T (Th17) cell-polarizing conditions or osteoclast differentiation conditions. BITRAP treatment inhibited the production of IL-17 and vascular endothelial growth factor but increased the production of IL-10 in CD4+ T cells, as well as directly suppressed osteoclastogenesis. Collagen-induced arthritis (CIA) and IL-1R antagonist (IL-1Ra) knockout mice were treated with BITRAP. Following injection in CIA mice, BITRAP rapidly migrated into the inflamed joints and remained there for 72 hours. Application of BITRAP attenuated the severity of autoimmune arthritis in CIA and IL-1Ra knockout mice by reducing the numbers of inflammatory cytokine-expressing cells and Th17 cells and antibody secretion. Finally, BITRAP suppressed STAT3 phosphorylation, as well as production of IL-17 and TNF-α, in murine splenic CD4+ T cells. These findings suggest that BITRAP, a bispecific fusion protein targeting TNF-α and IL-21, may be an effective treatment to overcome the limitations of anti-TNF therapy for patients with rheumatoid arthritis.

IL-12p40 homodimer, a natural antagonist of IL-12 and IL-23, performs an important role in the expression of proinflammatory cytokines that is essential for Th1 and Th17 immune responses. Here, we reveal the therapeutic and immunosuppressive effect of the IL-12p40 subunit ((p40)2-Fc) in an experimental autoimmune arthritis model. We hypothesized that (p40)2-Fc may reduce the inflammatory response and the activation of T cells. In this study, we intraperitoneally injected (p40)2-Fc into collagen induced arthritis (CIA) mice to identify whether (p40)2-Fc attenuates CIA severity. (p40)2-Fc reduced the development of CIA, joint inflammation and cartilage destruction. (p40)2-Fc also significantly decreased the concentration of serum immunoglobulin as well as the number of T cells and C II specific T cells. In addition, osteoclastogenesis in (p40)2-Fc treated mice was down-regulated compared to the mice treated with (p40)2-Fc control. We observed that (p40)2-Fc treatment alleviates arthritis in mice with CIA, reducing inflammation and osteoclast differentiation. These findings suggest that (p40)2-Fc can be a potential therapeutic approach for autoimmune arthritis.

Glucosinolates (GSs) are common anionic plant secondary metabolites in the order Brassicales. Together with glucosinolate hydrolysis products (GSHPs), they have recently gained much attention due to their biological activities and mechanisms of action. We review herein the health benefits of GSs/GSHPs, approaches to improve the plant contents, their bioavailability and bioactivity. In this review, only literature published between 2010 and March 2020 was retrieved from various scientific databases. Findings indicate that these compounds (natural, pure, synthetic, and derivatives) play an important role in human/animal health (disease therapy and prevention), plant health (defense chemicals, biofumigants/biocides), and food industries (preservatives). Overall, much interest is focused on in vitro studies as anti-cancer and antimicrobial agents. GS/GSHP levels improvement in plants utilizes mostly biotic/abiotic stresses and short periods of phytohormone application. Their availability and bioactivity are directly proportional to their contents at the source, which is affected by methods of food preparation, processing, and extraction. This review concludes that, to a greater extent, there is a need to explore and improve GS-rich sources, which should be emphasized to obtain natural bioactive compounds/active ingredients that can be included among synthetic and commercial products for use in maintaining and promoting health. Furthermore, the development of advanced research on compounds pharmacokinetics, their molecular mode of action, genetics based on biosynthesis, their uses in promoting the health of living organisms is highlighted.

Transcriptional analysis that uncovers fruit ripening-related gene regulatory networks is increasingly important to maximize quality and minimize losses of economically important fruits such as plums. RNA sequencing (RNA-Seq) and quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) are important tools to perform high-throughput transcriptomics. The success of transcriptomics depends on the high-quality transcripts from polyphenolic- and polysaccharide-enriched plum fruits, whereas reliability of quantification data relies on accurate normalization using suitable reference gene(s). We optimized a procedure for high-quality RNA isolation from vegetative and reproductive tissues of climacteric and non-climacteric plum cultivars and conducted high-throughput transcriptomics. We identified 20 candidate reference genes from significantly non-differentially expressed transcripts of RNA-Seq data and verified their expression stability using qRT-PCR on a total of 141 plum samples which included flesh, peel, and leaf tissues of several cultivars collected from three locations over a 3-year period. Stability analyses of threshold cycle (C T) values using BestKeeper, delta (Δ) CT, NormFinder, geNorm, and RefFinder software revealed S AND protein-related trafficking protein (MON), elongation factor 1 alpha (EF1α), and initiation factor 5A (IF5A) as the best reference genes for precise transcript normalization across different tissue samples. We monitored spatiotemporal expression patterns of differentially expressed transcripts during the developmental process after accurate normalization of qRT-PCR data using combination of two best reference genes. This study also offers a guideline to select best reference genes for future gene expression studies in other plum cultivars.

Ethnomedicinal knowledge of plant-derived bioactives could help us in discovering new therapeutic compounds of great potential. Certainly, dandelion has been used in traditional ethno-medicinal systems (i.e., Chinese, Arabian, Indian, and Native American) to treat different types of cancer. Though, dandelion is highly vigorous, but the potential mode of action is still unclear. In the current study, the antiproliferative activity of methanolic extracts of dandelion root (MEDr) on cell viability of HepG2, MCF7, HCT116, and normal Hs27 was investigated. It was observed that MEDr (500 μg/mL) drastically decreased the growth of HepG2 cell line, while the effect on MCF7 and HCT116 cell lines was less pronounced and no effect has been observed in Hs27 cell lines. The MEDr also enhanced the phosphorylation level of AMPK of HepG2 cells, which considered crucial in cancer treatment and other metabolic diseases. The AMPK activation by MEDr noticed in the current study has never been reported previously. The results regarding the number of apoptotic cells (HepG2 cells) were in line with the cell viability test. The current observations clearly demonstrated the potency of MEDr against liver cancer with validation that dandelion could control AMPK and thus cancer in the treated cell lines.

Dysfunction of T helper 17 (Th17) cells leads to chronic inflammatory disorders. Signal transducer and activator of transcription 3 (STAT3) orchestrates the expression of proinflammatory cytokines and pathogenic cell differentiation from interleukin (IL)-17-producing Th17 cells. However, the pathways mediated by STAT3 signaling are not fully understood. Here, we observed that Fos-related antigen 1 (FRA1) and JUNB are directly involved in STAT3 binding to sites in the promoters of Fosl1 and Junb. Promoter binding increased expression of IL-17 and the development of Th17 cells. Overexpression of Fra1 and Junb in mice resulted in susceptibility to collagen-induced arthritis and an increase in Th17 cell numbers and inflammatory cytokine production. In patients with rheumatoid arthritis, FRA1 and JUNB were colocalized with STAT3 in the inflamed synovium. These observations suggest that FRA1 and JUNB are associated closely with STAT3 activation, and that this activation leads to Th17 cell differentiation in autoimmune diseases and inflammation.

In the pursuit of sustainable agriculture through environment and human health friendly practices, we evaluated the potential of a novel gibberellins (GAs) producing basidiomycetous endophytic fungus Porostereum spadiceum AGH786, for alleviating salt stress and promoting health benefits of soybean. Soybean seedlings exposed to different levels of NaCl stress (70 and 140 mM) under greenhouse conditions, were inoculated with the AGH786 strain. Levels of phytohormones including GAs, JA and ABA, and isoflavones were compared in control and the inoculated seedlings to understand the mechanism through which the stress is alleviated. Gibberellins producing endophytic fungi have been vital for promoting plant growth under normal and stress conditions. We report P. spadiceum AGH786 as the ever first GAs producing basidiomycetous fungus capable of producing six types of GAs. In comparison to the so for most efficient GAs producing Gibberella fujikuroi, AGH786 produced significantly higher amount of the bioactive GA3. Salt-stressed phenotype of soybean seedlings was characterized by low content of GAs and high amount of ABA and JA with reduced shoot length, biomass, leaf area, chlorophyll contents, and rate of photosynthesis. Mitigation of salt stress by AGH786 was always accompanied by high GAs, and low ABA and JA, suggesting that this endophytic fungus reduces the effect of salinity by modulating endogenous phytohormones of the seedlings. Additionally, this strain also enhanced the endogenous level of two isoflavones including daidzen and genistein in soybean seedlings under normal as well as salt stress conditions as compared to their respective controls. P. spadiceum AGH786 boosted the NaCl stress tolerance and growth in soybean, by modulating seedlings endogenous phytohormones and isoflavones suggesting a valuable contribution of this potent fungal biofertilizer in sustainable agriculture in salt affected soils.

Objective.To investigate the expression of fractalkine and identify the clinical effects of fractalkine and its receptor (CX3CR1) in patients with primary Sjögren syndrome (pSS).Methods.Serum fractalkine levels were determined by ELISA. Immunohistochemical staining was done to compare the expression of fractalkine and CX3CR1 between salivary glands (SG) of patients with SS and controls. The cells to be merged with fractalkine were evaluated by confocal microscopy. Type of CX3CR1-expressing cells among infiltrating lymphocytes in SG was analyzed by confocal microscopy. Further, associations among fractalkine, proinflammatory cytokines, and clinical profiles were investigated.Results.Serum fractalkine levels in patients with pSS were higher than those in the control group (p = 0.026). SG expression of fractalkine and its receptor was upregulated in patients with pSS compared to that in the controls by immunohistochemistry. Higher histological grade was associated with more fractalkine-positive cells per total epithelial cells. Epithelial cells were the main fractalkine-expressing cell type in the SG. Serum fractalkine levels were significantly correlated with proinflammatory cytokines levels (interleukin 17: r = 0.685, p = 0.029; tumor necrosis factor-α: r = 0.444, p = 0.003), antinuclear antibody (r = 0.349, p = 0.022), and immunoglobulin G levels (r = 0.325, p = 0.044). Serum fractalkine levels in patients with extraglandular manifestations of pSS were significantly higher than in those without extraglandular manifestations (p = 0.026).Conclusion.Fractalkine and CX3CR1 may play a role in the pathogenesis of pSS, including extraglandular manifestations.

Acute graft-versus-host disease (aGVHD) is a major cause of mortality in allogeneic bone marrow transplantation. Here, the diminishing effect of activator protein 1 (AP-1) blocking with a synthetic retinoid (SR11302) on the severity of aGVHD in a murine model was investigated. MHC-mismatched strain combinations were used in vivo: C57BL/6 (H-2kb) donors into lethally irradiated BALB/c (H-2kd) recipients. SR11302 inhibited alloreactive T cell response in a dose-dependent manner and negatively regulated signal transducer and activator of transcription 3 (STAT3) activation. AP-1 blocking in T cells inhibited the differentiation of Th1 and Th17. Conversely, Foxp3+ regulatory T cells (Treg) population dramatically expanded. Transfer of SR11302-treated donor splenocytes into lethally irradiated recipients diminished the lethality and clinical severity of aGVHD. In line with these results, AP-1 blocking in donor splenocytes exhibited reduced Th17/Th1 population and enhanced in vivo Treg population. Beneficial Treg expanding property of SR11302 was associated with the induction of Foxp3 and STAT5 transcription factor, where the inhibiting property of Th17 was achieved by suppressing the phosphorylated form of STAT3 and enhancing SOCS3. In conclusion, the preventive potential of AP-1 inhibitor in aGVHD may be accomplished by altering CD4+ T cell differentiation through modulating transcription factors.

Objective Intravenous immunoglobulin (IVIG) is used as a therapeutic agent in various autoimmune diseases. The aims of this study were to investigate the therapeutic effects of IVIG on collagen-induced arthritis (CIA) and identify the mechanism responsible for any therapeutic effects. Methods IVIG was administered to mice with CIA, and the in vivo effects were determined. Th17 and Treg cell frequencies were analyzed by flow cytometry, and cytokine levels in the supernatant were measured by enzyme-linked immunosorbent assay. Subpopulations of T cells and B cells in the spleen were assessed by confocal microscopy. Results The arthritis severity score and incidence of arthritis were lower in mice treated with IVIG compared with untreated mice. Histopathologic analysis showed less joint damage in mice treated with IVIG. The expression of proinflammatory cytokines, specific type II collagen antibodies, and osteoclast markers was significantly reduced in mice treated with IVIG. Administration of IVIG induced increased FoxP3 expression and inhibited Th17 cell development. The number of FoxP3+ Treg cells was increased, and the number of Th17 cells was decreased in the spleens of mice treated with IVIG. The number of FoxP3+ follicular helper T cells was increased, and subsequent maturation of germinal center B cells was inhibited by IVIG. In addition, IVIG up-regulated interleukin-10 (IL-10) and Fcγ receptor IIB expression. The treatment effects of IVIG on arthritis were lost in IL-10–knockout mice. Conclusion These results showed that IVIG has therapeutic effects by modulating CD4+ T cell differentiation. The therapeutic effects of IVIG are dependent on IL-10.

IL-6–mediated STAT3 signaling is essential for Th17 differentiation and plays a central role in the pathogenesis of rheumatoid arthritis. To investigate the molecular mechanism underlying the antirheumatic effects and T cell regulatory effects of STAT3 inhibition, we studied the effects of the JAK 2 inhibitor AG490 on Th17 cell/regulatory T cell (Treg) balance and osteoclastogenesis. AG490 was administered to mice with collagen-induced arthritis (CIA) via i.p. injection, and its in vivo effects were determined. Differential expression of proinflammatory cytokines, including IL-17A, IL-1β, and IL-6, was analyzed by immunohistochemistry. Levels of phosphorylated STAT3 and STAT5 and differentiation of Th17 cells and Tregs after AG490 treatment in our CIA model were analyzed by immunostaining. In vitro development of Th17 cells and Tregs was analyzed by flow cytometry and real-time PCR. AG490 ameliorated the arthritic phenotype in CIA and increased the proportion of Foxp3+ Tregs. In contrast, the proportion of IL-17A–producing T cells and levels of inflammatory markers were reduced in AG490-treated mice. Numbers of p-STAT3+ CD4+ T cells and p-STAT5+ CD4+ T cells were reduced and elevated, respectively, after treatment with AG490. Furthermore, AG490 markedly increased the expression of molecules associated with Treg development (ICOS, programmed cell death protein 1, ICAM-1, and CD103). The development and function of osteoclasts were suppressed by AG490 treatment. Our results suggest that AG490, specifically regulating the JAK2/STAT3 pathway, may be a promising treatment for rheumatoid arthritis.

Objective The small molecule halofuginone has been shown to inhibit fibrosis, angiogenesis, and tumor progression. This study was undertaken to evaluate the effects of halofuginone in preventing autoimmune arthritis in mice. Methods The effects of halofuginone on joint diseases were assessed by clinical scoring and histologic analysis. Protein expression levels were confirmed by immunohistochemistry, enzyme-linked immunosorbent assay, flow cytometry, and/or Western blotting. The expression levels of messenger RNA (mRNA) for various molecules were determined by real-time polymerase chain reaction (PCR). Proliferation of osteoclast precursors was assessed by bromodeoxyuridine uptake. Osteoclast differentiation and activity were determined by quantifying tartrate-resistant acid phosphatase (TRAP)–positive multinucleated cells and area of resorbed bone. Results Treatment with halofuginone suppressed the development of autoimmune arthritis and reciprocally regulated Th17 cells and FoxP3+ Treg cells. These effects of halofuginone on Th17 differentiation involved increased signaling of ERK and reduction of STAT-3 and NF-ATc1 expression. Furthermore, halofuginone induced the expression of indoleamine 2,3-dioxygenase (IDO) in dendritic cells, leading to reduced production of Th17 cells. In addition, halofuginone prevented the formation and activity of osteoclasts through suppression of transcription factors, such as activator protein 1 and NF-ATc1, and inhibited cell cycle arrest by the committed osteoclast precursors via expression of Ccnd1 encoding cyclin D1. Conclusion Taken together, our results suggest that halofuginone is a promising therapeutic agent for the treatment of Th17 cell–mediated inflammatory diseases and bone diseases.

Objective To investigate the impact of STA-21, a promising STAT-3 inhibitor, on the development and progression of inflammatory arthritis and to determine the possible mechanisms by which STA-21 has antiarthritic effects in interleukin-1 receptor antagonist–knockout (IL-1Ra–KO) mice, an animal model of rheumatoid arthritis (RA). Methods IL-1Ra–KO mice were treated with intraperitoneal injections of STA-21 (0.5 mg/kg) or vehicle 3 times per week for 3 weeks. The mouse joints were assessed for clinical and histologic features of inflammatory arthritis. CD4+CD25+FoxP3+ Treg cells and CD4+IL-17+ cells were defined. Human peripheral blood mononuclear cell–derived monocytes or mouse bone marrow–derived monocyte/macrophage (BMM) cells were cultured in the presence of macrophage colony-stimulating factor alone or together with RANKL and various concentrations of STA-21, followed by staining of the cells for tartrate-resistant acid phosphatase activity to determine osteoclast formation. Results STA-21 suppressed inflammatory arthritis in IL-1Ra–KO mice. The proportion of Th17 cells was decreased and the proportion of Treg cells expressing FoxP3 was markedly increased in the spleens of STA-21–treated mice. Adoptive transfer of CD4+CD25+ T cells obtained from STA-21–treated IL-1Ra–KO mice markedly suppressed inflammatory arthritis. In vitro treatment with STA-21 induced the expression of FoxP3 and repressed IL-17 expression in both mouse and human CD4+ T cells. Moreover, STA-21 prevented both mouse BMM cells and human monocytes from differentiating into osteoclasts in vitro. Conclusion STA-21 improved the clinical course of arthritis in IL-1Ra–KO mice. It increased not only the number of Treg cells but also the function of the Treg cells. It also suppressed Th17 cells and osteoclast formation. These data suggest that STA-21 might be an effective treatment for patients with RA.

Objective STAT-3 is a key transcriptional factor in the interleukin-6 (IL-6)–mediated differentiation of Th17 cells. Because Th17 is believed to be a central player in rheumatoid arthritis (RA), we sought to evaluate whether an endogenous inhibitor of the STAT3 gene, GRIM-19 (gene associated with retinoid–interferon–induced mortality 19), could attenuate the progression and severity of murine collagen-induced arthritis (CIA) through suppression of Th17 cells and, reciprocally, could increase expression of Treg cells. Methods Overexpression of GRIM-19 was produced either by intravenous/intramuscular administration of a GRIM-19 overexpression vector in DBA1/J mice or by development of GRIM-19–transgenic (Tg) mice on a C57BL/6 background. Clinical signs were scored for arthritis severity, and mouse splenocytes, serum, and joint tissue were obtained for immunostaining and histologic analyses. Results The numbers of CD4+IL-17+ cells and CD4+pSTAT3+ cells were decreased, while the numbers of CD4+CD25+Foxp3+ cells and CD4+pSTAT5+ cells were increased, in both GRIM-19 vector–transfected and GRIM-19–Tg mice. Administration of the GRIM-19 overexpression vector into mice with CIA markedly suppressed the clinical and histologic signs of arthritis in the affected joints. Similarly, when CIA was induced in GRIM-19–Tg mice, the arthritis phenotype was markedly attenuated and the expression of inflammatory cytokines (IL-1β, IL-6, tumor necrosis factor α, and IL-17) in the arthritic joints was also significantly reduced. Moreover, bone marrow–derived monocyte/macrophages obtained from GRIM-19–Tg mice showed attenuated RANKL–induced osteoclastogenesis in vitro. Conclusion GRIM-19 improved the clinical and histologic features of CIA and also inhibited osteoclast formation. These findings suggest that GRIM-19 may be a novel treatment agent for RA.

Bone destruction is critical in the functional disability of patients with rheumatoid arthritis (RA). Osteoclasts, specialized bone-resorbing cells regulated by cytokines, such as receptor activator of NF-κB ligand (RANKL), are primarily implicated in bone destruction in RA. The aim of the study was to examine whether tumor necrosis factor–like weak inducer of apoptosis (TWEAK), a member of the tumor necrosis factor superfamily, has osteoclastogenic activity in patients with RA and in animal models, including mice with collagen-induced arthritis (CIA) and IL-1 receptor antagonist knockout (IL-1RaKO) mice. TWEAK was increased in the synovium, synovial fluid, and serum of patients with RA and in the synovium of CIA mice and IL-1RaKO mice. TWEAK induced RANKL expression in mixed joint cells and splenocytes from CIA mice, IL-1RaKO mice, and fibroblast-like synoviocytes from patients with RA. Both osteoclast precursor cells and osteoclasts express TWEAK receptor fibroblast growth factor–inducible 14. In addition, TWEAK enhanced in vitro osteoclastogenesis without the presence of RANKL-providing cells and by inducing RANKL expression in fibroblast-like synoviocytes. Moreover, treatment with fibroblast growth factor–inducible 14–Fc inhibited RANKL-induced osteoclastogenesis, indicating that endogenous TWEAK also has osteoclastogenic activity. Our data demonstrated that TWEAK promotes osteoclastogenesis in RA, suggesting that therapeutic strategies targeting TWEAK could be effective for treatment of patients with RA, especially in preventing bone destruction.

Objective To investigate the connection between p53 and interleukin-17–producing Th17 cell/Treg cell balance in rheumatoid arthritis (RA). Methods Th17 cell and Treg cell frequencies were analyzed by flow cytometry, and cytokine levels in the supernatant were determined using enzyme-linked immunosorbent assays. The expression of transcription factors was analyzed by immunostaining and Western blotting, and the interactions between p53 and STAT-3 or STAT-5 were determined by immunoprecipitation–Western blot analysis. A p53 agonist was administered in the collagen-induced arthritis (CIA) model, and the effects in vivo were determined. Results CD4+ T cells from p53–/– mice decreased the activity of STAT-5, lowered the level of phosphorylated STAT-5, and compromised Treg cell differentiation. The protein p53 bound STAT-5 directly, and this interaction was enhanced with increasing p53 activity. Under inflammatory conditions, p53 suppressed Th17 cell differentiation and skewed T cells toward Treg cell differentiation through the activation of STAT-5 signaling cascades. In mice with CIA, injection of a p53 overexpression vector or an antagonist of Mdm2 had the effect of controlling arthritis development in vivo. The regulatory effect of p53 was recapitulated in the cells of RA patients, with more pronounced suppression due to the repressed status of p53 in RA. Conclusion We demonstrated a link between p53-mediated and STAT-mediated regulation of Th17 cells/Treg cells in RA. Our results suggest that factors involved in this pathway might constitute novel therapeutic targets for the treatment of RA.

Bone destruction and inflammation are closely linked. Cytokines play an important role in inflammatory bone destruction by upregulating the receptor activator of nuclear factor-κB (NF-κB) ligand (RANKL). The direct role of cytokines that act in a non-RANKL-dependent manner has yet to be elucidated. The aim of this study was to investigate the direct osteoclastogenic properties of inflammatory cytokines at different time-points of osteoclastogenesis. Mouse bone marrow macrophages were stimulated with the macrophage colony-stimulating factor (M-CSF) and various concentrations of RANKL. Inflammatory cytokines, such as tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, IL-17 and IL-23, were added to the culture system of osteoclastogenesis. Two time-points of cytokine treatment were set. The ‘early’ effect of each cytokine was investigated at the time of first RANKL treatment, whereas the ‘late’ effect was investigated 48 h after the first RANKL challenge. Osteoclast differentiation and function were assessed using an osteoclast marker [tartrate-resistant acid phosphatase (TRAP)] and by visualization of pit formation. A permissive level of RANKL was required for cytokine-associated osteoclastogenesis in all experiments. In the M-CSF/RANKL monocellular culture system, IL-1β enhanced and IL-6 decreased osteoclast formation in a dose-dependent manner, regardless of temporal differences. Other cytokines showed various responses according to the phase of osteoclast maturation and the concentration of each cytokine and RANKL. Furthermore, luciferase assays showed that both IL-1β and RANKL activated the NF-κB signaling pathway. Collectively, our data revealed that targeting IL-1β may be a promising strategy to inhibit inflammation-associated bone destruction and osteoporosis.

PTEN is a tyrosine phosphatase with significant function in inhibiting STAT3 activation. Recently, inactivation of STAT3 has been demonstrated as a therapeutic candidate for autoimmune arthritis. The expression of PTEN controlled by p53 regulates autoimmune arthritis through modulating the balance between Th17 and Treg. We hypothesized that PTEN regulated by p53 might reduce CIA severity and inflammatory response via inhibiting STAT3 activation. Our results revealed that PTEN could ameliorate experimental autoimmune arthritis by reducing STAT3 activity and Th17 differentiation. Systemic infusion of PTEN overexpression downregulated CIA severity. In addition, PTEN overexpression decreased the activation of T cells and modulated reciprocal differentiation of Th17 and Treg cells. We observed that PTEN expression downregulated by p53 deficiency induced the activation of STAT3. Loss of p53 exacerbated autoimmune arthritis and dysregulated the population of Th17 and Treg. These data suggest that induction of STAT3-modulatory activity of PTEN may be a therapeutic target for rheumatoid arthritis therapy.

Background: Foxp3 is a key regulator of the development and function of regulatory T cells (Tregs), and its expression is thought to be T cell-restricted. We found that B cells in mice can express Foxp3 and B cells expressing Foxp3 may play a role in preventing the development of collagen-induced arthritis (CIA) in DBA/1J mice. Methods: Foxp3 expression was modulated in CD19(+) B cells by transfection with shRNA or using an over-expression construct. In addition, Foxp3-transfected B cells were adoptively transferred to CIA mice. We found that LPS or anti-IgM stimulation induced Foxp3 expression in B cells. Foxp3-expressing B cells were found in the spleens of mice. Results: Over-expression of Foxp3 conferred a contact-dependent suppressive ability on proliferation of responder T cells. Down-regulation of Foxp3 by shRNA caused a profound induction in proliferation of responder T cells. Adoptive transfer of Foxp3(+)CD19(+) B cells attenuated the clinical symptoms of CIA significantly with concomitant suppression of IL-17 production and enhancement of Foxp3 expression in CD4(+) T cells from splenocytes. Conclusion: Our data indicate that Foxp3 expression is not restricted to T cells. The expression of Foxp3 in B cells is critical for the immunoregulation of T cells and limits autoimmunity in a mouse model.

Anti-cyclic citrullinated peptide antibody (anti-CCP antibody) is very useful for the diagnosis of rheumatoid arthritis (RA) and is associated with articular erosions. The specificity of anti-CCP antibody in the diagnosis of RA has been reported to be about 95 %. Because of its higher specificity in RA, we assessed the clinical features of primary Sjogren's syndrome (pSS) who were positive for anti-CCP antibody. We assessed the clinical features of 405 pSS patients. After 60 (range 7-98) months, 23 (5.6 %) patients previously diagnosed with pSS had progressed to RA. Comparing the anti-CCP positive group with the negative group, laboratory test results for anti-CCP titer and rheumatoid factor positivity with respect to clinical outcome and progression to RA, arthralgia and arthritis were significantly different. Multivariate regression analysis also showed that anti-CCP antibody titer was independently associated with progression to RA. The odds ratio of anti-CCP positivity in terms of progression to RA was 2.5 (95 % CI 1.7-3.7). Testing for anti-CCP antibody in pSS patients with arthritis may allow for the prediction of progression to RA.

Objective To investigate the impact of STAT-3–mediated regulation on Th17 differentiation in patients with rheumatoid arthritis (RA). Methods CD4+ T cells isolated from peripheral blood (PB) and synovial fluid (SF) were stimulated to differentiate into Th17 cells or Treg cells. The activity of STAT-3 was knocked down by transfecting CD4+ T cells with small interfering RNA (siRNA). After 3 days in culture, the proportions of Th17 cells and Treg cells were measured by flow cytometry, and the production of interleukin-17 (IL-17) was measured by reverse transcriptase–polymerase chain reaction and enzyme-linked immunosorbent assay. Results The levels of IL-17, IL-6, IL-23, IL-1, and tumor necrosis factor α were significantly higher in RA SF and synovial tissue than in SF and synovial tissue from osteoarthritis patients. In RA synovial tissue, the expression of STAT-3 increased in proportion to the severity of synovitis, as shown by stromal cellularity, intimal hyperplasia, and inflammatory infiltration. The degree of Th17 differentiation was highest in RA SF, followed by RA PB, and lowest in normal subjects. In CD4+ T cells, transfection with STAT-3 siRNA prevented Th17 differentiation of mononuclear cells from RA PB and SF but increased the proportion of Treg cells. In contrast, inhibition of STAT-5, the transcription factor for Treg cells, increased the proportion of Th17 cells and reduced that of Treg cells. Conclusion Our findings indicate that modulation of STAT-3 in CD4+ T cells affects the differentiation of Th17 cells and Treg cells in patients with RA. This role of STAT-3 in RA synovial T cells may provide a new therapeutic target for the management of RA.

Tumor necrosis factor (TNF)-like weak inducer of apoptosis (TWEAK) is an inflammatory cytokine that modulates several biological responses by inducing chemokines and proinflammatory cytokines. We hypothesized that TWEAK could promote secretion of IL-17, an amplifier of inflammatory arthritis. To test this, we investigated the capacity of TWEAK to induce IL-17 production in T cells via the fibroblast growth factor-inducible gene 14 (Fn14, also known as TWEAK receptor) signal pathway in rheumatoid arthritis (RA). Fn14 and IL-17 were highly expressed in arthritic tissues of collagen-induced arthritis (CIA) mice. TWEAK induced production of IL-17 alone and synergistically with lipopolysaccharide. In naïve murine T cells, TWEAK promoted Th17 differentiation. The expression of Fn14 was predominant in Th17 cells. TWEAK and IL-17 concentrations were significantly higher in synovial fluid and serum in RA patients than OA patients. In addition, we identified CD4(+)IL-17(+)Fn14(+) cells in synovium from RA patients. TWEAK promoted IL-17 production synergistically with IL-23 or IL-21 and blockade of Fn14 with Fn14-Fc suppressed Th17 differentiation. Conversely, this treatment enhanced Treg differentiation. These results suggest that TWEAK induces IL-17 production and may be a therapeutic target in the treatment of RA.

In oral tolerance, locally instigated tolerance in the gut propagate to systemic tolerance. In order to investigate the mechanism, we analyzed indoleamine 2,3-dioxygenase (IDO) expression in splenic dendritic cell (DC) subsets and tested whether DCs suppress collagen-induced arthritis (CIA) by inducing regulatory T cells (Tregs). The proportion of IDO-expressing cells was higher in the CD11b(+) subset of splenic DCs from orally tolerized CIA mice. These DCs suppressed type II collagen-specific T cell proliferation and promoted Treg induction from CD4(+)CD25(-) T cells using transforming growth factor-β. These DCs also increased the expression of cytotoxic T lymphocyte antigen-4 and programmed death-1 on Tregs. When adoptively transferred, spenic IDO-expressing CD11b(+) DCs from tolerized animals suppressed the development of arthritis, increased the Treg/Th17 cell ratio, and decreased the production of inflammatory cytokines in the spleen. Taken together, a distinct subset of splenic IDO(+)CD11b(+)DCs is responsible for the systemic immune regulation in oral tolerance.

Catheters are implanted into the peritoneal cavity during the process of peritoneal dialysis. Though these catheters may be effective and beneficial, the impact of catheters on the immune system is poorly understood. Catheters and other devices implanted in the peritoneal cavity elicit a foreign body reaction. However, the immunological consequences of this remain uncharacterized. To model this, catheters were implanted into the peritoneal cavity of healthy mice. Catheter implantation induced rapid cellular changes within the peritoneal cavity. Whereas B-cells and T-cells were reduced, catheter implantation was associated with the rapid expansion of F4/80-low-positive, CD11b-positive macrophages that elaborated IL-10, and suppressed T-cell division and Th1 skewing in co-culture assays. Peritoneal catheter elicited macrophages had increased Jmjd3 but reduced NF-κB activation, and their emergence was MyD88-dependent. Collectively, these studies indicate that foreign body implantation into the peritoneal cavity is associated with the expansion of suppressor macrophages. Whether peritoneal cavity catheter implantation may have systemic immunoregulatory roles remains to be explored.

Tacrolimus is a calcineurin inhibitor, and it is used for the treatment of rheumatoid arthritis (RA). It works by inhibiting nuclear factor of activated T cells and inducting immunosuppression. This study aims to evaluate the influence of tacrolimus on the bone metabolism of patients with RA. Twenty-eight RA patients in three centers received tacrolimus 3 mg once daily for 24 weeks. Blood samples for evaluating bone metabolism and cytokines were collected at Weeks 0 and 24. We measured the serum C-telopeptide of type I collagen (sCTx-I), osteocalcin and inflammatory cytokines. We analyzed the data using the Kruskal-Wallis test and Spearman's correlation. IL-2 and IL-6 were significantly decreased after the administration of tacrolimus (p = 0.027 and p = 0.024). There was no significant difference in the serum level of sCTx-I before and after treatment. The level of serum osteocalcin at Week 24 was significantly increased compared to the level at Week 0 (p = 0.002). The increase of osteocalcin was correlated with the reductions of IL-2 and IFN-γ (r = 0.405, p = 0.033 and r = 0.380, p = 0.046, respectively). Tacrolimus treatment increased bone formation markers in RA patients. This suggests that tacrolimus may play a role to inhibit bone erosion by increasing bone formation as well as improving the clinical symptoms of RA.

The interleukin-33 (IL-33)/ST2 pathway has emerged as an intercellular signaling system that participates in antigen-allergen response, autoimmunity and fibrosis. It has been suggested that IL-33/ST2 signaling has been involved in the pathogenesis of rheumatoid arthritis (RA), because IL-33 and its receptor have been specifically mapped to RA synovium. The aim of this study was to determine the levels of IL-33 and sST2 in sera and synovial fluids in patients with RA. The serum level of IL-33 was significantly higher in patients with RA (294.9 ± 464.0 pg/mL) than in healthy controls (96.0 ± 236.9 pg/mL, P = 0.002). The synovial fluid level of IL-33 was significantly higher in RA patients than in osteoarthritis patients. The level of serum sST2 was higher in RA patients than in healthy controls (P = 0.042). A significant relationship was found between the levels of IL-33 and IL-1β (r = 0.311, P = 0.005), and IL-33 and IL-6 (r = 0.264, P = 0.017) in 81 RA patients. The levels of IL-33, sST2 and C-reactive protein decreased after conventional disease-modifying antirheumatic drugs treatment in 10 patients with treatment-naive RA. Conclusively, IL-33 is involved in the pathogenesis of RA and may reflect the degree of inflammation in patients with RA.

Osteoclastogenesis plays an important role in joint destruction in rheumatoid arthritis (RA). IL-15 is a pleiotropic proinflammatory cytokine that appears to help mediate the pathological bone loss. This study was undertaken to explore the signaling molecules essential for osteoclastogenesis mediated by IL-15 in rheumatoid synovial fibroblasts. Expression of phospholipase D1 (PLD1) and osteoclast-related gene expression in synovial tissues and their modulation by treatment with IL-15 and different inhibitors in synovial fibroblasts of RA patients were evaluated using immunohistochemistry and quantitative polymerase chain reaction. The levels of IL-15 in serum and synovial fluid were measured by ELISA. The effects of IL-15 and phosphatidic acid (PA) on osteoclast formation were evaluated in cocultures of rheumatoid synovial fibroblasts and peripheral blood monocytes or monocytes alone in the presence of M-CSF and RANKL. The levels of RANKL and PLD1 but not PLD2 were upregulated significantly by IL-15, and the RANKL level was significantly upregulated by PA in rheumatoid synovial fibroblasts. Blocking PA production with 1-butanol and siRNA against PLD1 significantly inhibited the IL-15-stimulated expression of RANKL and PLD1. IL-15 levels were significantly higher in serum and synovial fluid from patients with RA than in osteoarthritis patients and healthy controls. IL-15 and PA induced osteoclast formation through the mitogen-activated protein kinases (MAPKs) and NF-κB signaling pathways. Activation of PLD1 contributes to IL-15-mediated osteoclastogenesis via the MAPKs and NF-κB signaling pathways in rheumatoid synovial fibroblasts. Our data suggest that PLD1 might be an efficient therapeutic strategy for preventing bone destruction in rheumatoid arthritis.

Label-free LC-MS/MS-based shot-gun proteomics was used to quantify the differential protein synthesis and metabolite profiling in order to assess metabolic changes during the development of citrus fruits. Our results suggested the occurrence of a metabolic change during citrus fruit maturation, where the organic acid and amino acid accumulation seen during the early stages of development shifted into sugar synthesis during the later stage of citrus fruit development. The expression of invertases remained unchanged, while an invertase inhibitor was up-regulated towards maturation. The increased expression of sucrose-phosphate synthase and sucrose-6-phosphate phosphatase and the rapid sugar accumulation suggest that sucrose is also being synthesized in citrus juice sac cells during the later stage of fruit development.

Grape seed proanthocyanidin extract (GSPE), which is the antioxidant derived from grape seeds, has been reported to possess a variety of potent properties. We have previously shown that GSPE attenuates collagen-induced arthritis. However the mechanism by which GSPE regulates the immune response remains unclear, although it may involve effects on the regulation of pathogenic T cells in autoimmune arthritis. To clarify this issue, we have assessed the effects of GSPE on differential regulation of Th17 and regulatory T (Treg) cells subsets in vitro in mouse and human CD4(+) T cells. We observed that GSPE decreased the frequency of IL-17(+)CD4(+)Th17 cells and increased induction of CD4(+)CD25(+)forkhead box protein 3 (Foxp3)(+) Treg cells. In vivo, GSPE effectively attenuated clinical symptoms of established collagen-induced arthritis in mice with concomitant suppression of IL-17 production and enhancement of Foxp3 expression (type II collagen-reactive Treg cells) in CD4(+) T cells of joints and splenocytes. The presence of GSPE decreased the levels of IL-21, IL-22, IL-26 and IL-17 production by human CD4(+) T cells in a STAT3-dependent manner. In contrast, GSPE induces Foxp3(+) Treg cells in humans. Our results suggest that GSPE possesses a reciprocal control over IL-17 and Foxp3. By potently regulating inflammatory T cell differentiation, GSPE may serve as a possible novel therapeutic agent for inflammatory and autoimmune diseases, including rheumatoid arthritis.

The aim of this study was to determine whether stimulation of toll-like receptor 2 (TLR2), TLR4, and TLR6 by their specific ligands induces the production of tumor necrosis factor-alpha (TNF-alpha) in fibroblast-like synoviocytes (FLS) from interleukin-1 receptor antagonist (IL-1Ra)-deficient mice. FLS were isolated from synovial tissues from IL-1Ra-deficient mice and stimulated with various ligands of TLRs. The concentrations of TNF-alpha, interleukin (IL)-1beta, and IL-10 in the culture supernatants of spleen cells were measured by ELISA, and mRNA levels were assessed by real-time PCR. The expression of TLR2, TLR4, TLR6, and TNF-alpha in the synovial tissue was quantified by immunohistochemistry. Cytokine production and TLR expression were measured in FLS stimulated in the presence of the TLR2 ligand PAM3, the TLR4 ligand lipopolysaccharide (LPS), and the TLR6 ligand zymosan, with and without blocking antibody to TNF-alpha and IL-1beta. Stimulation of TLR2, TLR4, and TLR6 by their specific ligands increased the production of TNF-alpha in FLS from IL-1Ra-deficient mice. The stimulatory effect of these TLR ligands showed a dose-dependent pattern. The combination of TLR2, TLR4, and TLR6 synergistically increased the production of TNF-alpha, IL-1beta, TLR2, TLR4, and TLR6. Addition of blocking antibodies to TNF-alpha and IL-1beta abrogated the stimulatory effect of the ligands of TLR2, TLR4, and TLR6 on the production of TNF-alpha, IL-1beta, TLR2, TLR4, and TLR6. These data show that TLR2, TLR4, and TLR6 ligation synergistically stimulates the production of TNF-alpha and IL-1beta in IL-1Ra-deficient mice and suggest that TLRs contribute to the perpetuation of spontaneous arthritis in this animal model.

To examine the effects of nuclear factor kappa B (NF-kappaB) inhibition on the secretion of macrophage migration inhibitory factor (MIF) in human CD4(+) T cells. Isolated human CD4(+) T cells were cultured for 24h with pharmacological inhibitors of NF-kappaB including parthenolide, pyrrolidine dithiocarbamate, BAY 11-7082, gliotoxin, oridonin, andrographolide, and NF-kappaB shRNA. MIF concentration was measured by intracellular flow cytometry, enzyme-linked immunosorbent assay, and real-time polymerase chain reaction. The intracellular concentrations O(2)(-), H(2)O(2), and glutathione were measured using the oxidation-sensitive fluorescent dyes dihydroethidium, dichlorodihydrofluorescein diacetate, and monochlorobimane, respectively. The amount of phosphorylated c-Jun was measured by Western blotting. Treatment of CD4(+) T cells with NF-kappaB inhibitors significantly increased MIF concentration in culture supernatants, MIF gene expression, and O(2)(-) production, and decreased the intracellular concentrations of MIF, H(2)O(2), and glutathione. Treatment with LY294002 (PI3K inhibitor) and SP600125 (JNK inhibitor) suppressed NF-kappaB inhibitor induced MIF mRNA expression and MIF secretion. LY294002 and SP600125 inhibited the parthenolide-induced phosphorylation of c-Jun. Treatment with H(2)O(2) decreased the amount of intracellular MIF protein and increased MIF concentration in the culture supernatant. N-acetylcysteine, an antioxidant precursor of glutathione, inhibited the parthenolide-induced and H(2)O(2)-induced secretion of MIF. These results indicate that pharmacological inhibition of NF-kappaB causes the release of MIF through de novo synthesis of MIF and the secretion of preformed MIF in CD4(+) T cells through the production of reactive oxygen species.

Objective.To examine the effect of interleukin 17 (IL-17) on the expression of Toll-like receptor (TLR)-2, 4, and 9 in collagen-induced arthritis (CIA) in mice.Methods.On Days 28 and 32 after induction of CIA in mice, phosphate-buffered saline (PBS group) or IL-17 (IL-17 group) was injected into both knee joints. On Day 35, mice were sacrificed. The severity of knee joint arthritis, synovial inflammation, and bone destruction was measured by a scoring system using macrography and histological analysis. Synovial expression of TLR-2, 4, 9, IL-17, IL-1ß, tumor necrosis factor-α (TNF-α), and IL-6 was determined by real-time PCR and immunohistochemistry. Synoviocytes of CIA mice were cultured with IL-17 and with neutralizing antibodies to cytokine, and the expression of TLR-2, 4, 9, IL-1ß, TNF-α, and IL-6 was determined by real-time RT-PCR.Results.In CIA mice, knee arthritis scores, synovial inflammation, bone destruction scores, and expression of synovial TLR-2, 4, and 9, IL-17, IL-1ß, TNF-α and IL-6 were higher in the IL-17 and PBS groups than in normal DBA1 mice. These variables were also significantly higher in the IL-17 group than in the PBS group. In CIA synoviocytes, IL-17 increased the expression of TLR-2, 4, and 9, and this effect was significantly alleviated by neutralizing antibodies to IL-17, IL-1ß, and IL-6.Conclusion.IL-17 aggravates joint inflammation and destruction, and increases the synovial expression of TLR-2, 4, and 9 by increasing IL-1ß and IL-6. These results imply that the IL-17-induced increase in expression of TLR-2, 4, and 9, and IL-1ß and IL-6 production are involved in the IL-17-induced aggravation of arthritis.

Endophytic fungi are known to play a vital role in the growth and development of their host plants. We isolated eleven endophytic fungi from the roots of sand-dune plant Elymus mollis and their growth-promoting ability was studied on waito-c rice and Atriplex gemelinii. We found that eight fungal isolates promoted growth of both plants. Fungal isolate EM-7-1 induced maximum growth promotion in waito-c rice (9.25 cm) and Atriplex gemelinii (3.1 cm), which was higher than wild-type Gibberella fujikuroi. Gibberellin analysis of EM-7-1 culture filtrate showed the presence of bioactive gibberellins GA1 (0.32 ng/ml), GA3 (5.76 ng/ml), GA4 (0.82 ng/ml) and GA7: (0.1 ng/ml) along with physiologically inactive GA5 (0.59 ng/ml), GA9 (5.38 ng/ml), GA20 (0.25 ng/ml) and GA24 (2.03 ng/ml). The fungal isolate EM-7-1 was identified as new strain of Gliomastix murorum (G. murorum KACC43902) with 99% sequence homology. This study reports the plant growth-promoting ability of genus Gliomastix and the presence of GA5 in the culture filtrate of fungi for the first time.

We previously showed that although systemic administration of alpha-galactosylceramide (alphaGalCer) or agonistic anti-CD40 induced functional maturation of dendritic cells (DC) in mesenteric lymph nodes, only the former treatment succeeded in breaking the induction of oral tolerance. In this study, we looked for the essential factor responsible for the disruption of oral tolerance. We found that lamina propria (LP)-DC was responsible for the oral OVA presentation and that Peyer's patch was not essential for the induction of oral tolerance. Therefore, we investigated the role of LP-DC. Treatment with alphaGalCer but not with anti-CD40 induced the full maturation of LP-DC at an early time point. This functional activation of LP-DC was mediated by strong activation of NKT cells that reside abundantly in the small intestinal lamina propria (SI-LP) and interferon-gamma partially contributed to the LP-DC activation. LP-DC isolated from alphaGalCer-treated OVA-fed mice induced the differentiation of naïve CD4+ T cells into Th1 and Th2 and was associated with the reduced Foxp3+ population. In contrast, LP-DC isolated from anti-CD40-treated OVA-fed mice failed to generate Th cell differentiation but induced more Foxp3+ CD4+ T cells. Our results demonstrate that triggered by NKT cells in SI-LP, functional maturation of Ag-capturing DC from SI-LP is necessary for the abrogation of oral tolerance induction.

IL-23, a clinically novel cytokine, targets CD4+ T cells. Recent IL-1Ra−/− mouse studies have demonstrated that IL-23 indirectly stimulates the differentiation of osteoclast precursors by enhancing IL-17 release from CD4+ T cells. IL-17, in turn, stimulates osteoclastogenesis in osteoclast precursor cells. In this study, we found that IL-23 up-regulates receptor activator of NF-κB ligand expression by CD4+ T cells, and thus contributes to osteoclastogenesis. This indirect pathway is mediated by NF-κB and STAT3. We have also demonstrated that IL-23 can influence osteoclastogenesis positively under the special conditions in the IL-1-dominant milieu of IL-1Ra−/− mice. We propose that IL-23-enhanced osteoclastogenesis is mediated mainly by CD4+ T cells. The results of this study show that IL-23 is a promising therapeutic target for the treatment of arthritis-associated bone destruction.

The receptor activator of nuclear factor kappaB ligand (RANKL) is an osteoclastogenic mediator, which is mainly expressed by stromal cells and osteoblast. However, T cells can also be an important provider for RANKL in special condition such as autoimmune arthritis. We examined the RANKL expression of hyporesponsive CD4+ T cells induced by oral feeding with type II collagen in collagen-induced arthritis (CIA) mice. The potential of RANKL expression in CD4+ T cells was downregulated in tolerance, as compared with CIA. One of possible explanations for this phenomenon is that CII-specific T cell activation was intrinsically impaired in oral tolerance, which caused suppression of RANKL expression of CD4+ T cells. We also investigated the extrinsic role of cytokine in this process. IL-17, well-known pro-inflammatory cytokine was upregulated in CIA and downregulated in tolerance. IL-17 had a potential to stimulate T cells to express RANKL in dose-dependent manner. IL-17-associated RANKL expression of CD4+ T cells was downregulated in oral tolerance, suggesting that the induction of tolerance ameliorates IL-17-induced RANKL expression of T cells in murine CIA. We also discovered that CIA - T cells could enhance osteoclastogenesis but not oral tolerance - T cells. Oral tolerance might be promising therapeutic option in viewpoints of modulating autoreactivity of CII which can induce not only IL-17 production but also RANKL expression in CD4+ T cells.

In the spleen, exogenous antigen is preferentially presented by CD8alpha+CD11b- DC to CD8 T cells and by CD8alpha-CD11b+ DC to CD4 T cells. However, it is not yet clear whether the same rule applies to other secondary lymphoid organs. To address this issue, we first classified secondary lymphoid tissues into three categories based on the expression pattern of CD8alpha and CD11b in C57BL/6 and BALB/c mice: (a) spleen, (b) mesenteric lymph node (MLN) and (c) other peripheral lymph nodes (PLN). We then analyzed the OVA-specific T cell-stimulating capacity of each DC subset after intravenous injection with soluble OVA. Our results show that, regardless of tissue origin, CD8alpha-CD11b+ DC generally present OVA to CD4 T cells, a finding that held true as well for CD8alpha+CD11b+ DC in PLN. In striking contrast, CD8alpha+CD11b- DC in spleen, CD8alpha-CD11b+ DC in MLN and CD8alpha+CD11b+ DC in PLN mainly cross-present OVA to CD8 T cells in their respective tissues. Of note, CD8alpha-CD11b+ DC in MLN and CD8alpha+CD11b+ DC in PLN present OVA to both CD4 T and CD8 T cells. Therefore, the antigen-presenting capacity of each distinct DC subset is determined by its anatomic environment in combination with its surface phenotype.

Toll-like receptors (TLRs) are pattern-recognition receptors that connect innate and adaptive immunity. Interleukin-15 (IL-15) is a proinflammatory, innate response cytokine that mediates pleiotropic effector functions in inflammatory synovitis of rheumatoid arthritis (RA). The aim of this study was to clarify whether stimulation of TLR2 and TLR4 by their specific ligands induces the production of IL-15 in fibroblast-like synoviocytes (FLS) from RA patients. FLS were isolated from RA synovial tissues and stimulated with the TLR2 ligand bacterial peptidoglycan (PGN) and the TLR4 ligand lipopolysaccharide (LPS). IL-15 in the culture supernatants was measured by ELISA, and mRNA levels were assessed by RT-PCR and real time PCR. The expression of TLR2, TLR4, and IL-15 in the RA synovium was quantified by immunohistochemistry and compared with values obtained in osteoarthritis synovium. IL-15 production increased in culture supernatants of RA FLS stimulated with PGN or PGN plus LPS, and this was upregulated at the transcriptional level. In contrast, LPS did not increase the level of IL-15 although it augmented the stimulatory effect of PGN on IL-15 production. Inhibition of nuclear factor (NF)-kappaB with a specific inhibitor abrogated the stimulatory effect of PGN or PGN plus LPS on IL-15. Neutralization of TLR2 with a blocking monoclonal antibody significantly reduced IL-15 production (P0.05), reflecting the functional relevance of TLR2 activation in the induction of IL-15 production. These data suggest that TLR2 activation in RA FLS by microbial constituents is involved in the induction of IL-15 and that TLR2 promotes inflammation through NF-kappaB. TLR4 augmented the stimulatory effect of TLR2 on IL-15, possibly contributing to the maintenance of synovitis in patients with RA.