MiR-485-5p promotes the development of osteoarthritis by inhibiting cartilage differentiation in BMSCs.

OBJECTIVE: To investigate whether microRNA-485-5p (miR-485-5p) can participate in osteoarthritis by inhibiting chondrogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) and promoting the secretion of inflammatory factors. MATERIALS AND METHODS: BMSCs were obtained from mouse bone marrow samples and identified by flow cytometry. The expression of specific genes and miR-485-5p in the differentiation of BMSCs was detected by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). The influence of miR-485-5p on chondrogenic differentiation was subsequently evaluated by toluidine blue staining, detection of chondrogenic specific gene expression and inflammatory factors. After over-expressing SOX9, it was assessed whether miR-485-5p can affect the chondrogenic differentiation of BMSCs by inhibiting SOX9, so as to promote the secretion of inflammatory factors. RESULTS: The miR-485-5p level was negatively correlated with the degree of differentiation of BMSCs. After overexpression of microRNA-485-5p in BMSCs, the expression of cartilage surface marker genes and toluidine blue staining were reduced, while the expression of cartilage surface inflammation factors, including interleukin and tumor necrosis factor, was significantly enhanced. Meanwhile, opposite results were observed when miR-485-5p was inhibited. In addition, overexpression of SOX9 could restore the secretion of inflammatory cytokines induced by microRNA-485-5p. CONCLUSIONS: MiR-485-5p can decrease the level of SOX9, promote the production of inflammatory factors on the cartilage surface, and block the differentiation of mouse BMSCs into chondrocytes.

Organochlorine pesticides in agricultural soil and vegetables from Tianjin, China.

Samples of eight types of vegetables, the rhizosphere soils, and bulk soils were collected from two sites (A and B) in Tianjin, China for the determination of hexachlorocyclohexane isomers (HCHs) and dichlorodiphenyltrichloroethane and metabolites (DDXs). The average concentrations of total HCHs and DDXs in the bulk soils were 3.6 and 80.1 ng/g for site A and 102 and 235 ng/g for site B, respectively. Relative accumulations of HCHs and DDXs in the rhizosphere soil from site A but not site B were demonstrated. The concentrations of total HCHs and DDXs in vegetable roots were 3.6-60 and 4.2-73 ng/g for site A and 15-152 and 7.1-136 ng/g for site B, respectively. Difference in bioaccumulation among various vegetables, especially between tuber and fibrous vegetables was significant. DDXs in spinach and cauliflower from site B and lindane (gamma-HCH) in cauliflower from both sites and violet from site B exceeded the maximum residual limits. Linear correlation of log-transformed HCHs and DDXs contents between the vegetable roots and the rhizosphere soils suggests the direct uptake of HCHs and DDXs.

Residues of hexachlorocyclohexane isomers and their distribution characteristics in soils in the Tianjin area, China.

Hexachlorocyclohexane (HCH) has a history of use in China. This paper presents the results of an investigation of HCH residue isomers and their distribution characteristics in soils near Tianjin, China. One hundred eighty-eight soil samples were collected from the Tianjin area. Four HCH isomers-alpha-HCH, beta-HCH, gamma-HCH, and delta-HCH-were detected using gas chromatography for all samples. Concentrations of the sum HCH ranged from 1.3 to 1095 ng g(-1), among which beta-HCH accounted for 52.5%. In addition, residues of HCH within Tianjin's urban areas were found to be higher. No significant differences were found between the residues of HCH in soils from waste irrigation areas and those in other areas. Total organic carbon content was determined to impact the residue levels of HCH in soils, while pH value and clay content were not related to concentrations of HCH. In general, all HCH isomers in soil samples had abnormally high residue levels, possibly the result of continuous use of HCH in this area.

Level and distribution of DDT in surface soils from Tianjin, China.

One hundred and eighty eight surface soil samples were collected from the Tianjin area to study the contamination of DDT and its metabolites. Measurements were taken for p,p'-DDE, p,p'-DDD, p,p'-DDT, o,p'-DDE, o,p'-DDD and o,p'-DDT for all samples. The results indicated that p,p'-DDT and p,p'-DDE were the predominant contaminant compounds in the surface soil samples, with mean concentrations of 27.5 and 18.8 ng g(-1) respectively. No significant differences in DDT concentrations were found between the soils from wastewater treated irrigated areas and other areas, suggesting that wastewater irrigation is not an important source of DDT in the area. However, the spatial distribution of soil DDTs levels in the area did correlate well with early direct application rates of pesticides. In addition, both pH level and organic carbon content are also known factors affecting the level of DDT and its metabolites. Although it was assumed that the use of these chemicals was banned in the early 1980s, the current concentration levels appear to be too high to be mere residuals after 20 years degradation.

[Structure and function of mouse p16INK4a locus].

Inactivation of p16INK4a is highly related with tumors. We obtained a 14.5 kb mouse genomic DNA fragment through screening the 129/SvJ mouse genomic library. Bioinformatics study suggests that the fragment contain three exons, which encode a 17,941 dolton polypeptide consisted of 168aa. The polypeptide has 7 potential phosphorylation sites, which indicates that the function of p16INK4a itself may be under the control of phosphorylation. Many interspersed elements and simple repeats were found in the noncoding region. These elements and repeats may cause retroposition and recombination and thus be responsible for some of the p16INK4a locus deletion. We also compared our sequence of exon 1 alpha with those published elsewhere and found that polymorphism may exist.