Wetland ecological index and assessment of spatial-temporal changes of wetland ecological integrity.

Long-term, quantitative, and dynamic monitoring of regional ecological integrity using remote sensing can provide powerful decision-making support for sustainable regional development. However, existing methods are unable to accurately evaluate the quality of the surface ecological integrity because they do not consider vegetation saturation and salinization of wetlands. In addition, the ecological fragility of wetlands is characterized by a high frequency of changes in ecological conditions over time, leading to a lack of directionality in the analysis of ecological changes over long time series. To accurately assess the surface ecological integrity, this study integrates environmental salinity (Baseline-based Soil Salinity Index, BSSI) and a new vegetation element (Improved Hyperspectral Image-based Vegetation Index, IHSVI), and proposes the wetland ecological index (WEI) for the ecological integrity assessment system. Combined with the annual ecological integrity assessment using the WEI, the Mann-Kendall test was used to obtain the nodes of long-term changes. The WEI-Mann Kendall (WEI-MK) framework indicates the direction of analysis and realizes clear long-term series change monitoring. In this study, we analyzed the spatial and temporal changes in ecological integrity in the Yellow River Delta from 1991 to 2020 based on the WEI-MK framework. The results showed that: 1) Compared with Remote Sensing-based Ecological Index (RSEI), the WEI improved the accuracy of wetland integrity evaluation to 89 %. The WEI also improved accuracy of assessments in other typical regions by approximately 10 %. 2) The selection of nodes based on the WEI-MK framework clarified the direction of environmental change analysis. The results show that although the quality of the terrestrial ecological environment has improved over the past 30 years in the Yellow River Delta, that of the marine ecological environment has gradually declined. In particular, the state of the marine ecological environment after 2016 should be of concern.

MeCP2 suppresses LIN28A expression via binding to its methylated-CpG islands in pancreatic cancer cells.

LIN28A aberrant expression contributes to the development of human malignancies. However, the LIN28A expression profile remains to be clarified. Herein, we report that LIN28A expression is directly associated with the methylation status of its two CpG island sites in pancreatic cancer cells. First, Bisulfite sequencing reveals that PANC1 cells possess the higher methylation rate at LIN28A CpG islands compared with SW1990 and PaTu8988 cells. Subsequently, LIN28A expression is increased at both mRNA and protein levels in pancreatic cancer cells treated with 5-Aza-2'-deoxycytidine (5-Aza-CdR), a DNA methyltransferase inhibitor. Further Chromatin immunoprecipitation (ChIP) assays indicate that methyl-CpG-binding protein 2 (MeCP2) binds preferentially to the two hypermethylated CpG islands sites at LIN28A promoter compare to MBD3. Expectedly, MeCP2 knockdown transcriptionally activates LIN28A expression in above cells, rather than MBD3 knockdown. Moreover, LIN28A overexpression remarkably improves OCT4, NANOG and SOX2 expression, and the ability of sphere and colony formation, and enhances the capacities of invasion in PaTu8988 and SW1990 cells, whereas LIN28A knockdown significantly inhibits the above malignant behaviors in PANC1 cells. These findings suggest that LIN28A is epigenetically regulated via MeCP2 binding to methylated-CpG islands, and may play a crucial role in pancreatic cancer progression.

Plasma microRNA expression profiles in Chinese patients with rheumatoid arthritis.

The outstanding characteristics of circulatory microRNAs (miRNAs) attract much attention in research on disease biomarkers and disease pathogenesis. This study aimed to identify the expression profiles of plasma miRNAs in patients with rheumatoid arthritis (RA). Thirty-three miRNAs were screened using an miRNA array, of which 9 miRNAs were validated as differentially expressed in the plasma of RA patients compared with healthy controls (HCs). miRNA-4634 (miR-4634), miR-181d and miR-4764-5p expression levels were increased, whereas miR-342-3p, miR-3926, miR-3925-3p, miR-122-3p, miR-9-5p and miR-219-2-3p expression levels were decreased in RA patients. The areas under the curve (AUCs) were generated to estimate the sensitivity and specificity of each miRNA or the panel of all 9 miRNAs as biomarkers for RA. AUCs for 9 individual miRNAs ranged from 0.6254 to 0.818; however, the AUC for the panel of 9 miRNAs reached 0.964. Levels of miR-122-3p, miR-3925-3p, miR-342-3p and miR-4764-5p expression showed significant differences between RA and other control groups. miR-4764-5p, miR-4634, miR-9-5p and miR-219-2-3p exhibited significant correlations with either plasma cytokine and chemokine levels or clinical features. In conclusion, this study identified 9-plasma miRNAs signature in Chinese patients with RA which may serve as noninvasive biomarkers for the diagnosis of RA.

Sonic hedgehog-glioma associated oncogene homolog 1 signaling enhances drug resistance in CD44(+)/Musashi-1(+) gastric cancer stem cells.

Drug resistance in gastric cancer largely results from the gastric cancer stem cells (GCSCs), which could be targeted to improve the efficacy of chemotherapy. In this study, we identified a subpopulation of GCSCs enriched in holoclones that expressed CD44(+)/Musashi-1(+) stem cell biomarkers, capable of self-renewal and proliferation. Enriched CD44(+)/Musashi-1(+) GCSCs demonstrated elevated expression of sonic hedgehog (SHH) and glioma-associated oncogene homolog 1 (GLI1), the well-known signaling pathway molecules involved in the drug resistance. Further, CD44(+)/Musashi-1(+) cells exhibited high drug efflux bump activity and were resistant to doxorubicin (Dox)-induced apoptosis, and unregulated the ATP-binding cassette sub-family G member 2 (ABCG2) expression,. The above effects on apoptosis were reversed in the presence of GLI inhibitors, GANT61 and GDC-0449, or by the knockdown of GLI1/SHH. Upon knockdown of GLI1, expression of ABCG2 was downregulated the antitumor effects were significantly improved as observed in the gastric cancer xenograft. Collectively, our study revealed that co-expression of CD44(+)/Musashi-1(+) could be used to identify GCSCs, which also accounts for the drug resistance in gastric cancer. SHH-GLI and its downstream effector ABCG2 could be better targeted to possibly improve the efficacy of chemotherapy in drug-resistant gastric cancers.

[Effects of lipopolysaccharide and phytohaemagglutinin on the level of microRNAs in mouse peripheral blood mononuclear cells].

OBJECTIVE: To investigate the effects of lipopolysaccharide (LPS) and phytohaemagglutinin (PHA) on the level of microRNAs in mouse peripheral blood mononuclear cells (PBMCs). METHODS: The mouse PBMCs were cultured in vitro and stimulated with 100 ng/mL LPS for 1 hour or 2 hours and 2.5 µg/mL phytohaemagglutinin (PHA) for 2 hours or 4 hours, respectively. The levels of miR-9, miR-122-3p, miR-181d and miR-342-3p in both PBMCs and culture supernatants were determined by real-time quantitative PCR (qRT-PCR). RESULTS: The levels of miR-9, miR-122-3p, miR-181d and miR-342-3p in PBMCs and culture supernatants had no significant difference between blank control and LPS stimulation group, nor did between LPS stimulation 2 hours group and 1 hour group. The levels of miR-9, miR-122-3p and miR-342-3p in PBMCs and culture supernatant had no significant difference between blank control and PHA stimulation group, nor did between PHA stimulation 4 hours group and 2 hours group. However, compared with blank control, the expression of miR-181d significantly increased after PHA stimulation, while the time of stimulation did not affect the miR-181d level significantly. CONCLUSION: The stimulation of PHA could promote the expression and secretion of miR-181d in mouse PBMCs.

Multiple genetic variants associated with primary biliary cirrhosis in a Han Chinese population.

Multiple genome-wide association studies of primary biliary cirrhosis (PBC) in both European and Japanese ancestries have shown significant associations of many genetic loci contributing to the susceptibility to PBC. Major differences in susceptibility loci between these two population groups were observed. In this study, we examined whether the most significant loci observed in either European and/or Japanese cohorts are associated with PBC in a Han Chinese population. In 1070 PBC patients and 1198 controls, we observed highly significant associations at CD80 (rs2293370, P = 2.67 × 10(-8)) and TNFSF15 (rs4979462, P = 3.86 × 10(-8)) and significant associations at 17q12-21 (rs9303277), PDGFB (rs715505), NF-κB1 (rs7665090), IL12RB2 (rs11209050), and STAT4 (rs7574865; all corrected P values <0.01). However, no association was observed for POU2AF1 (rs4938534), IL12A (rs485499 and rs2366408), IL7R (rs6897932), CXCR5 (rs715412), SOCS1 (rs725613), and TNFRSF1A (rs1800693). STAT4 (rs7574865) was strongly associated after additional control samples were analyzed. Our study is the first large-scale genetic analysis in a Han Chinese PBC cohort. These results do not only reflect that Han Chinese PBC patients share common genetic susceptibility genes with both their Japanese and European counterparts but also suggest a distinctly different genetic susceptibility profile.

Functional characterization of myeloid-derived suppressor cell subpopulations during the development of experimental arthritis.

Recent evidence indicates the existence of subpopulations of myeloid-derived suppressor cells (MDSCs) with distinct phenotypes and functions. Here, we characterized the role of MDSC subpopulations in the pathogenesis of autoimmune arthritis in a collagen-induced arthritis (CIA) mouse model. The splenic CD11b(+) Gr-1(+) MDSC population expanded in CIA mice, and these cells could be subdivided into polymorphonuclear (PMN) and mononuclear (MO) MDSC subpopulations based on Ly6C and Ly6G expression. During CIA, the proportion of splenic MO-MDSCs was increased in association with the severity of joint inflammation, while PMN-MDSCs were decreased. MO-MDSCs expressed higher levels of surface CD40 and CD86 protein, but lower levels of Il10, Tgfb1, Ccr5, and Cxcr2 mRNA. PMN-MDSCs exhibited a more potent capacity to suppress polyclonal T-cell proliferation in vitro, compared with MO-MDSCs. Moreover, the adoptive transfer of PMN-MDSCs, but not MO-MDSCs, decreased joint inflammation, accompanied by reduced levels of serum cytokine secretion and the frequencies of Th1 and Th17 cells in draining lymph nodes. These results suggest that there could be a shift from potently suppressive PMN-MDSCs to poorly suppressive MO-MDSCs during the development of experimental arthritis, which might reflect the failure of expanded MDSCs to suppress autoimmune arthritis.

Th17 cells play a critical role in the development of experimental Sjögren's syndrome.

OBJECTIVE: Although Th17 cells have been increasingly recognised as an important effector in various autoimmune diseases, their function in the pathogenesis of Sjögren's syndrome (SS) remains largely uncharacterised. This study aims to determine the role of Th17 cells in the development of experimental SS (ESS). METHODS: The ESS was induced in wildtype and IL-17A knockout (IL-17 KO) C57BL/6 mice immunised with salivary glands (SG) proteins. Phenotypic analysis of immune cells in the draining cervical lymph nodes (CLN) and SG was performed by flow cytometry and immunofluorescence microscopy. To determine the role of Th17 cells in ESS, immunised IL-17 KO mice were adoptively transferred with in vitro-generated Th17 cells and monitored for SS development. The salivary flow rate was measured, whereas inflammatory infiltration and tissue destruction in SG were assessed by histopathology. RESULTS: SG protein-immunised mice developed overt SS symptoms with increased Th17 cells detected in CLN and within lymphocytic foci in inflamed SG. Notably, immunised IL-17 KO mice were completely resistant for SS induction, showing no evidence of disease symptoms and histopathological changes in SG. Adoptive transfer of Th17 cells rapidly induced the onset of ESS in immunised IL-17 KO mice with markedly reduced saliva secretion, elevated autoantibody production and pronounced inflammation and tissue damage in SG. CONCLUSIONS: Our findings have defined a critical role of Th17 cells in the pathogenesis of ESS. Further studies may validate Th17 cell as a potential target for treating SS.

Infiltration of alternatively activated macrophages in cancer tissue is associated with MDSC and Th2 polarization in patients with esophageal cancer.

Myeloid derived suppressor cells (MDSCs) expand in cancer bearing hosts and contribute to tumor immune evasion. M2 macrophages constitute a major cellular component of cancer-related inflammation. However, the correlation between circulating MDSCs and infiltrating M2 macrophages in tumor tissues from patients with esophageal cancer (ECA), and its potential relationship with the polarization of Th2 cells remain unclear. In the present study, we showed the level of MDSCs in PBMC and Arg1 in plasma were significantly elevated in ECA patients, and the increased ratio of MDSC in PBMC was closely related to the expression of CD163 in cancer tissues. In addition, the ECA patients exhibited remarkable increases in the mRNA levels of IL-4 and GATA3, as well as the protein levels of IL-13 and IL-6, but IFN-γ and IL-12 in peripheral blood were decreased. Our data indicate that the increased Th2 cytokines are associated with MDSCs and M2 macrophages polarization, and foster the infiltration of CD163+M2 macrophages in cancer tissues, which promote the formation of immunosuppressive microenvironment in ECA patients.

A Trichosanthin-derived peptide suppresses type 1 immune responses by TLR2-dependent activation of CD8(+)CD28(-) Tregs.

A group of 15-aa-long Trichosanthin-derived peptides was synthesized and screened based on their differential abilities to induce low-responsiveness in mouse strains with high and low susceptibility. One of them was conjugated to form a homo-tetramer Tk-tPN. At concentrations of 0.1-50 µg/ml, Tk-tPN activated CD8(+)CD28(-) Tregs in vitro to induce immune suppression as effectively as the native Trichosanthin but did not exhibit cytotoxicity. In EAE mice which were pre-treated with Tk-tPN or Tk-tPN-activated CD8(+) T cells, a marked attenuation of clinical scores was recorded together with an expansion of the CD8(+)CD28(-) Treg from 2.2% to 36.1% in vivo. A pull-down assay and signal transduction analyses indicated that the ability of Tk-tPN to convert the CD8(+)CD28(-) Treg-related cytokine secretion pattern from type 1 to type 2 depends on the TLR2-initiated signaling in macrophages. The high production of IL-4/IL-10 by the Tk-tPN-activated CD8(+)CD28(-) Treg suggests the value of using Tk-tPN as a therapeutic reagent for Th1-dominant immunological diseases.

The expression of Toll-like receptor 8 and its relationship with VEGF and Bcl-2 in cervical cancer.

BACKGROUND: Cervical cancer is one of the most common cancers in women worldwide, often associated with the infection of human papillomavirus (HPV). Toll-like receptor 8 (TLR8), a pattern recognition receptor, is involved in viral nucleic acid sensing. Recently TLR8 has been shown to be expressed in cancer cells, and it has been suggested that it may help cancer cell growth and tumor development. The objective of this study is to investigate the expression of TLR8 expression and its relationship with Bcl-2 and VEGF in cervical cancer cells. METHODOLOGY/PRINCIPAL: The mRNA expression levels of Bcl-2, VEGF and TLR-7,-8,-9 in newly diagnosed cervical cancer patients were detected by quantitative real-time PCR (qRT- PCR). Epifluorescence microscope was used to determine the presence of TLR8 protein in Hela cells. The cell cycle and apoptosis were analyzed by flow cytometer, and the cell proliferation was measured by MTT assay. Our data showed the increased mRNA levels of TLR8 in human cervical cancer samples as well as in HeLa cells, a cell line derived from a human cervical cancer. In addition, there was a positive correlation between the expression levels of TLR8 and Bcl-2 and VEGF in cervical cancer patients. When Hela cells were treated with TLR8 agonist CL075, the percentage of cells in G2/M +S was remarkably increased, accompanied by increased COX-2, BCL-2 and VEGF mRNA levels. CONCLUSIONS/SIGNIFICANCE: The mRNA expression level of TLR8 in the patients with cervical cancer and Hela cells were up-regulated, it consistent with the increased expression of VEGF and Bcl-2. The results suggest that TLR8 may be an interesting therapeutic target in cervical cancer.

The closely related CD103+ dendritic cells (DCs) and lymphoid-resident CD8+ DCs differ in their inflammatory functions.

Migratory CD103+ and lymphoid-resident CD8+ dendritic cells (DCs) share many attributes, such as dependence on the same transcription factors, cross-presenting ability and expression of certain surface molecules, such that it has been proposed they belong to a common sub-lineage. The functional diversity of the two DC types is nevertheless incompletely understood. Here we reveal that upon skin infection with herpes simplex virus, migratory CD103+ DCs from draining lymph nodes were more potent at inducing Th17 cytokine production by CD4+ T cells than CD8+ DCs. This superior capacity to drive Th17 responses was also evident in CD103+ DCs from uninfected mice. Their differential potency to induce Th17 differentiation was reflected by higher production of IL-1ß and IL-6 by CD103+ DCs compared with CD8+ DCs upon stimulation. The two types of DCs from isolated lymph nodes also differ in expression of certain pattern recognition receptors. Furthermore, elevated levels of GM-CSF, typical of those found in inflammation, substantially increased the pool size of CD103+ DCs in lymph nodes and skin. We argue that varied levels of GM-CSF may explain the contrasting reports regarding the positive role of GM-CSF in regulating development of CD103+ DCs. Together, we find that these two developmentally closely-related DC subsets display functional differences and that GM-CSF has differential effect on the two types of DCs.

Blockade of Notch signaling ameliorates murine collagen-induced arthritis via suppressing Th1 and Th17 cell responses.

Recent studies have demonstrated that Notch signaling is critically involved in the regulation of immune response and contributes to autoimmune pathogenesis. Here, Notch signaling was found to be activated in CD4(+) T cells and synovial tissue from collagen-induced arthritis mice. In vivo administration of the γ-secretase inhibitor N-[N-(3,5-difluorophenacetyl-l-alanyl)]-S-phenylglycine t-butyl ester (DAPT) substantially reduced the severity of arthritic symptoms and joint damage in collagen-induced arthritis mice. Notably, DAPT treatment significantly suppressed Th1- and Th17-cell responses in spleen and lymph nodes and reduced IFN-γ and IL-17 levels in plasma. In polarization culture, DAPT treatment markedly reduced Th17 cell expansion from naïve T cells, whereas fusion protein of the Notch receptor ligand delta-like 3 significantly increased the frequency and absolute number of Th17 cells. These results suggest a novel therapeutic strategy for treatment of human rheumatoid arthritis by targeting Notch signaling using γ-secretase inhibitors.

ABCB2 (TAP1) as the downstream target of SHH signaling enhances pancreatic ductal adenocarcinoma drug resistance.

Hedgehog signaling plays critical roles in drug resistance of PDAC. We demonstrate that SHH is highly expressed in PDAC patients and cell lines. SHH signaling protects PDAC cells against gemcitabine induced apoptosis, because either over-expression or knockdown of SHH in PDAC cells affects the sensitivity to gemcitabine. Mechanistic studies show that ABCB2 serves as the downstream target of SHH signaling, leading to the drug resistance of PDAC cells. Combinational treatments with gemcitabine and cyclopamine yield synergistic antitumor effects in vitro and in vivo. Our study suggests that inhibiting SHH signaling or targeting ABCB2 gene improves the efficacy of chemotherapy in patients with PDAC.

SRC kinase family inhibitor PP2 promotes DMSO-induced cardiac differentiation of P19 cells and inhibits proliferation.

BACKGROUND: It has been reported recently that PP2, a Src family kinase inhibitor, promotes selective cardiogenesis in embryonic stem cells. However, there is no other research proved pro-cardiogenic characteristic of PP2 so far. In this study, we explored the potential cardiogenic effect of PP2 on P19 cells differentiation. METHODS: P19-αMHC-EGFP cell line was established by transfecting P19 cells with αMHC-EGFP vector in order to evaluate cardiogenesis with EGFP. P19-αMHC-EGFP cells and P19 cells were induced to differentiate into cardiomyocytes with 1%DMSO, 5 µmol/L PP2, or both 1%DMSO and 5 µmol/L PP2. Differentiated cells from P19-αMHC-EGFP cells were then assessed under confocal microscope. Western-blot and RT-PCR were also performed to detect expression of cardiac troponin I and cardiac transcription factors respectively. In addition, the effects of PP2 on proliferation of P19 cells were further examined using Cell Counting Kit-8. RESULTS: EGFP positive cells were firstly detected on day 7 and PP2 alone cannot induce efficient cardiac differentiation of P19-αMHC-EGFP cells. However PP2 supplementation dramatically increases DMSO induced cardiac differentiation than DMSO alone. It was also found that PP2 inhibit proliferation of P19 cells in both a dose-dependent manner and a time-dependent manner. CONCLUSION: PP2 alone cannot substitute DMSO to induce cardiac differentiation, however, PP2 supplementation drastically promotes DMSO-induced cardiac differentiation of P19 cells. The increased percentages of differentiated cardiac myocytes is partly resulting from cell proliferative inhibit effect of PP2 in undifferentiated P19 cells. P19-αMHC-EGFP cell line has the potential to be used for regenerative therapies in experimental models of heart repair.

Correlation between circulating myeloid-derived suppressor cells and Th17 cells in esophageal cancer.

AIM: To perform a comprehensive investigation into the potential correlation between circulating myeloid-derived suppressor cells (MDSCs) and Th17 cells in esophageal cancer (ECA). METHODS: A total of 31 patients newly diagnosed with ECA and 26 healthy subjects were included in the current study. The frequencies of MDSCs and Th17 cells in peripheral blood were determined by flow cytometry. The mRNA expression of cytokines, arginase 1 (Arg1) and inducible NO synthase (iNOS) in peripheral blood mononuclear cells (PBMCs) and plasma Arg1 were assessed by real-time polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. RESULTS: There was an increased prevalence of MDSCs in the peripheral blood from ECA patients (15.21% ± 2.25%) when compared with healthy control (HC) (1.10% ± 0.12%, P < 0.0001). The plasma levels of Arg1 in ECA patients were significantly higher than those in HC (28.28 ± 4.10 ng/mL vs 9.57 ± 1.51 ng/mL, P = 0.0003). iNOS mRNA levels in the peripheral blood of ECA patients also showed a threefold increase compared with HC (P = 0.0162). The frequencies of Th17 cells (CD4⁺IL-17A⁺) were significantly elevated in ECA patients versus HC (3.50% ± 0.33% vs 1.82% ± 0.19%, P = 0.0001). Increased mRNA expression of IL-17 and ROR-γt was also observed in ECA patients compared with HC (P = 0.0041 and P = 0.0004, respectively), while the mRNA expression of IL-6 and tumor necrosis factor-α (TNF-α) showed significant decreases (P = 0.0049 and P < 0.0001, respectively). No obvious correlations were found between the frequencies of MDSCs and Th17 cells in the peripheral blood from ECA patients(r = -0.1725, P = 0.3534). Arg1 mRNA levels were positively correlated with levels of IL-6 (r = 0.6404, P = 0.0031) and TNF-α (r = 0.7646, P = 0.0001). Similarly, iNOS mRNA levels were also positively correlated with levels of IL-6 (r = 0.6782, P = 0.0007) and TNF-α (r = 0.7633, P < 0.0001). CONCLUSION: This study reveals the relationship between circulating MDSCs and Th17 cells, which may lead to new immunotherapy approaches for ECA based on the associated metabolites and cytokines.

PTD-hFOXP3 protein acts as an immune regulator to convert human CD4(+)CD25(-) T cells to regulatory T-like cells.

Regulatory T cells (Tregs) are critical for maintaining self-tolerance and homeostasis, and have potential application in clinical disease therapy, such as autoimmune diseases and transplant rejection, but their numbers are limited. FOXP3 is a key transcription factor controlling Tregs development and function. Although transfection of CD4(+)CD25(-) lymphocytes with the FOXP3 gene can convert them to Treg-like cells, there is the risk of insertional mutagenesis and thus an alternative to genetic intervention is sought. The protein transduction domain (PTD) from the HIV transactivator of transcription is a useful tool to deliver protein to the cytoplasm and nucleus. In this study, we generated a fusion protein linking the human FOXP3 to PTD (PTD-hFOXP3), and explored its function in T cells. The results showed that the PTD rapidly and effectively delivered the hFOXP3 protein into cells where it localized not only in the cytoplasm, but also to the nucleus. PTD-hFOXP3-transduced Jurkat cells (human T lymphoma cell line) and CD4(+)CD25(-) T cells failed to proliferate and produce IL-2 and IFN-γ, but produced large amounts of the cytokines IL-4, IL-10, and TGF-ß, in response to TCR stimulation in vitro. PTD-hFOXP3-transduced CD4(+)CD25(-) T cells also expressed high levels of CTLA-4 and low levels of CD25 after stimulation. Most importantly, PTD-hFOXP3-transduced T cells inhibited the proliferation of activated CD4(+)CD25(-) T cells. Furthermore, chromatin immunoprecipitation assays demonstrated that PTD-hFOXP3 can bind with the IL-2 gene promoter and repress the expression of IL-2. These results indicate that PTD-hFOXP3 has the capability to convert conventional T cells to Treg-like cells.

Increased frequency of circulating follicular helper T cells in patients with rheumatoid arthritis.

Follicular helper T (Tfh) cells are recognized as a distinct CD4(+) helper T-cell subset, which provides for B-cell activation and production of specific antibody responses, and play a critical role in the development of autoimmune disease. So far, only one study investigated the circulating Tfh cells increased in a subset of SLE patients. Since relatively little is known about the Tfh cells in rheumatoid arthritis (RA) patients, in this study, Tfh-cell frequency, related cytokine IL-21, and transcription factor Bcl-6 were investigated in 53 patients with RA and 31 health controls. Firstly, we found that the frequency of CD4(+)CXCR5(+)ICOS(high) Tfh cells was increased significantly in the peripheral blood of RA patients, compared with that in healthy controls. It is known that Tfh cells are critical for directing the development of an antibody response by germinal centers B cells; secondly, we observed that the Tfh-cell frequency is accompanied by the level of anti-CCP antibody in RA patients. Furthermore, expression of Bcl-6 mRNA and plasma IL-21 concentrations in RA patients was increased. Taken together, these findings have shown that the increased frequency of circulating Tfh cells is correlated with elevated levels of anti-CCP antibody, indicating the possible involvement of Tfh cells in the disease progression of RA.

IL-10-producing regulatory B10 cells ameliorate collagen-induced arthritis via suppressing Th17 cell generation.

IL-10-producing CD1d(hi)CD5(+) B cells, also known as B10 cells, have been shown to possess a regulatory function in the inhibition of immune responses, but whether and how B10 cells suppress the development of autoimmune arthritis remain largely unclear. In this study, we detected significantly decreased numbers of IL-10-producing B cells, but increased IL-17-producing CD4(+) T (Th17) cells in both spleen and draining lymph nodes of mice during the acute stage of collagen-induced arthritis (CIA) when compared with adjuvant-treated control mice. On adoptive transfer of in vitro expanded B10 cells, collagen-immunized mice showed a marked delay of arthritis onset with reduced severity of both clinical symptoms and joint damage, accompanied by a substantial reduction in the number of Th17 cells. To determine whether B10 cells directly inhibit the generation of Th17 cells in culture, naive CD4(+) T cells labeled with carboxyfluorescein succinimidyl ester (CFSE) were co-cultured with B10 cells. These B10 cells suppressed Th17 cell differentiation via the reduction of STAT3 phosphorylation and retinoid-related orphan receptor γt (RORγt) expression. Moreover, Th17 cells showed significantly decreased proliferation when co-cultured with B10 cells. Although adoptive transfer of Th17 cells triggered the development of collagen-induced arthritis in IL-17(-/-)DBA/1J mice, co-transfer of B10 cells with Th17 cells profoundly delayed the onset of arthritis. Thus, our findings suggest a novel regulatory role of B10 cells in arthritic progression via the suppression of Th17 cell generation.

IL-17 contributes to cardiac fibrosis following experimental autoimmune myocarditis by a PKCß/Erk1/2/NF-κB-dependent signaling pathway.

Myocarditis is a common clinical cardiovascular disease, and some patients progress to dilated cardiomyopathy (DCM) with chronic heart failure. Common viral infections are the most frequent cause of myocarditis, but other pathogens and autoimmune diseases have also been implicated. T(h)17 cells are novel IL-17-producing effector T helper cells that play an important role in the development of autoimmune myocarditis. Furthermore, IL-17 is also important in post-myocarditis cardiac remodeling and progression to DCM. However, the mechanisms whereby IL-17 and IL-17-producing cells promote the progression of cardiac fibrosis remain unclear. We therefore investigated whether IL-17 directly induced cardiac fibrosis in experimental autoimmune myocarditis (EAM) and explored the possible molecular mechanisms. The EAM model was induced and serum IL-17 level was detected by ELISA; western blot, immunofluorescence and sirius red staining were used to analyze the collagen expression. PCR was used to assay the IL-17RA and IL-17RC. The results indicated that IL-17 induced cardiac fibrosis both in vitro and in vivo. The protein kinase C (PKC)ß/Erk1/2/NF-κB (Nuclear Factor κappa B) pathway was involved in the development of myocardial fibrosis and IL-17 contributed to cardiac fibrosis following EAM via this pathway. These results provide the first direct evidence for the involvement of the PKCß/Erk1/2/NF-κB signaling pathway in IL-17-induced myocardial fibrosis.