Sox11-modified mesenchymal stem cells accelerate cartilage defect repair in SD rats.

Cartilage has a limited capacity to heal. Previously, we have shown that overexpression of Sox11 in rMSCs (Rat Mesenchymal Stem Cells) by lentivirus-mediated gene transfer leads to enhanced tri-lineage differentiation and accelerated bone formation in fracture model of rats. We observed that the fracture repair in the rats that received Sox11-modified rMSCs injection proceeded through an endochondral ossification process much faster than those in the control groups. However, the detailed role of Sox11 in rMSCs chondrogenic differentiation, as well as cartilage defect, is still not clearly clarified. Therefore, this study tests the hypothesis that Sox11 promotes chondrogenesis and cartilage defect repair by regulating ß-catenin. Sox11 was transduced into rMSCs using lentiviruses. The expression levels of ß-catenin and its downstream genes were evaluated by quantitative RT-PCR. The transcriptional activation of ß-catenin was proved by dual-luciferase reporter assay and co-immunoprecipitation was performed to evaluate Sox11-ß-catenin interaction. In addition, a cartilage defect model in SD rats was used to evaluate the cartilage regeneration ability of Sox11-modified rMSCs in vivo. We found that Sox11 transcriptionally activated ß-catenin expression and discovered the core promoter region (from - 242 to - 1414) of ß-catenin gene for Sox11 binding. In addition, Sox11 might regulate ß-catenin at the post-transcriptional level by protein-protein interaction. Finally, using a cartilage defect model in rats, we found Sox11-modified rMSCs could improve cartilage regeneration. Taken together, our study shows that Sox11 is an important regulator of chondrogenesis and Sox11-modified rMSCs may have clinical implication for accelerating cartilage defect healing.

Profiling kidney microRNAs from juvenile grass carp (Ctenopharyngodon idella) after 56days of oral exposure to decabromodiphenyl ethane.

Grass carp (Ctenopharyngodon idella) is one of the most important species in China. Decabromodiphenyl ethane (DBDPE) is a brominated flame retardant that has been used widely in industry, and has been observed to accumulate in the tissues of fish from South China. Evidence has shown that DBDPE is toxic to aquatic animals, but the molecular response has been unclear. MicroRNAs (miRNAs) are small noncoding and negative regulatory RNAs that are 20-24 nucleotides in length, which are involved in a wide range of biological processes. We took advantage of deep-sequencing techniques to accurately and comprehensively profile the kidney miRNA expression of grass carp after 8weeks of oral exposure to DBDPE. After mapping sequencing data to the genome and Expressed Sequence Tags (ESTs) of grass carp, we identified 493 miRNAs in the sequenced grass carp samples, which included 51 new miRNAs. The results indicated that 5 miRNAs were significantly down-regulated and 36 miRNAs were significantly up-regulated (FDR<0.001, 1.5-fold change) after DBDPE exposure. Real-time quantitative PCR (RT-qPCR) was performed on 4 miRNAs from the two samples, and the sequencing and RT-qPCR data were consistent. This study provides the first comprehensive identification of grass carp miRNAs, and the first expression analysis of grass carp miRNAs following DBDPE exposure. The results indicated that miRNAs have potential for use as biomarkers.

N-3-(oxododecanoyl)-L-homoserine lactone promotes the induction of regulatory T-cells by preventing human dendritic cell maturation.

N-3-(Oxododecanoyl)-L-homoserine lactone (C12) is a small bacterial signaling molecule secreted by Pseudomonas aeruginosa (PA), which activates mammalian cells through TLR4-independent mechanisms. C12 acts as an immunosuppressant and it has been shown to modulate murine bone marrow-derived dendritic cell-mediated T-helper 2 (Th2) cell polarizations in vitro. In the present study, we initially examined the impact of C12 on the maturation of human monocyte-derived dendritic cells (Mo-DCs) and the induction of regulatory T-cells (iTregs) in culture. Our findings demonstrate that C12-treated Mo-DCs failed to undergo lipopolysaccharide (LPS)-induced maturation. At the molecular level, C12 blocked the upregulation of surface molecules, including CD11c, HLA-DR, CD40, and CD80, and it switched to an interleukin (IL)-10(high), IL-12p70(low) phenotype. Moreover, C12 selectively inhibited the capacity of Mo-DCs to stimulate the proliferation of allogeneic CD4(+) T-cells. Otherwise, the C12-treated Mo-DCs promoted the generation of CD4(+)CD25(+)Foxp3(+)-induced regulatory T-cells (iTregs) and enhanced their IL-10 and transforming growth factor (TGF)-ß production associated with reduced interferon (IFN)-γ and IL-12p70 production. These findings provide new insights towards understanding the persistence of chronic inflammation in PA infection.

Heat shock factor 1 is a transcription factor of Fas gene.

In mammalian cells, stress-induced expression of heat shock protein is controlled by heat shock factor 1 (HSF1). However, HSF1 functions as a regulator of additional genes. In this study, we observed that heat treatment effectively induced expression of Fas. Using bioinformatics, a high affinity and functional HSF1-binding element within the -1996/-1985 oligonucleotide of the 5'-flanking region of the Fas gene was found, and was determined by electrophoretic mobility shift assay and chromatin immunoprecipitation assay. Exogenous expression of a constitutively activative HSF1, induced Fas gene transcription and protein synthesis in the absence of heat stress. Moreover, RNA interference-mediated HSF1 gene-silencing attenuated Fas expression in a heat-induced model. Our results suggested that HSF1 is an important transcription factor of Fas gene.

Dominant-positive HSF1 decreases alpha-synuclein level and alpha-synuclein-induced toxicity.

Alpha-synuclein aggregation and cytotoxicity are widely considered to play a critical role in the process of Parkinson's disease. Heat shock proteins are a large family of cellular protective molecules in most kinds of cells. In this study, we examined the impact of dominant-positive heat shock transcription factor 1 (HSF1) on alpha-synuclein over-expression cellular model of Parkinson's disease. We found that over-expression of alpha-synuclein could form alpha-synuclein immunopositive inclusions and result in cell death; dominant-positive HSF1 dramatically increased the expression of HSP70 in SH-SY5Y cells, and significantly decreased the level and cytotoxicity of alpha-synuclein. Taken together, these data indicate that dominant-positive HSF1 plays an important role in suppressing alpha-synuclein aggregation and toxicity in SH-SY5Y cells. Parkinson's disease which is marked by alpha-synuclein aggregation may be treated by increasing a set of endogenous heat shock proteins.

Induction of macroautophagy by heat.

Macroautophagy is a regulated bulk degradation process of cellular components, mainly long-lived proteins or cytoplasmic organelles. Nutrient depletion is a classic inducer of macroautophagy. In this report, we have induced heat-mediated macroautophagy in several cell lines in the absence of nutrient depletion. Heat treatment increased the autophagic markers LC3-I and LC3-II at the protein levels. Interestingly, expression of a constitutively active HSF1 mutant suppressed basal LC3-II protein level and heat-induced increase of LC3-II. Our results provide evidence that heat is a potent inducer of macroautophagy in mammalian cells, and implicate the negative role of active HSF1 in this process.