MiR-1246 Promotes LPS-Induced Inflammatory Injury in Chondrogenic Cells ATDC5 by Targeting HNF4γ.

BACKGROUND/AIMS: Osteoarthritis (OA) is a common inflammatory joint disease. miRNAs are associated with OA and functionally implicated in the pathogenesis of the disease. In the present study, we investigated the role of miR-1246 in the lipopolysaccharide (LPS)-induced inflammatory injury of ATDC5 cells. METHODS: ATDC5 cells were cultured and treated with LPS in a series of concentration (0, 1, 5, and 10 µg/ml) for 5 h. The cells were transfected with miR-1246-mimic, inhibitor, si-HNF4γ or negative control, then were assessed for cell viability using CCK8 assay, apoptosis by flow-cytometry and expressions of miR-1246 and pro-inflammatory cytokines by qRT-PCR and western blot analysis. RESULTS: Cell viability was significantly reduced and cell apoptosis was added in ATDC5 cells injured with LPS at the dosage of 5 and 10 µg/ml. Relative mRNA expressions of pro-inflammatory cytokines (IL-1ß, IL-6, IL-8 and TNF-α) were significantly increased. miR-1246 was up-regulated in ATDC5 cells treated with LPS. Moreover, miR-1246 overexpression aggravated LPS-induced decrease in cell viability, increase in apoptosis and overproduction of pro-inflammatory factors. mRNA and protein expressions of HNF4γ were significantly suppressed in cells transfected with miR-124-mimic. Further, miR-1246 knockdown alleviated LPS-induced inflammatory injury by up-regulating the expression of HNF4γ and activation of PI3K/AKT and JAK/STAT pathways. CONCLUSIONS: Suppression of miR-1246 alleviated LPS-induced inflammatory injury in chondrogenic ADTC5 cells by up-regulation of HNF4γ and activation of PI3K/AKT and JAK/STAT pathways. The findings of this study will provide a novel viewpoint regarding miR-1246 target for clinical.

[Vertical variability of Pinus sylvestris var. mongolica tree ring delta13C and its relationship with tree ring width in northern Daxing' an Mountains of Northeast China].

A measurement was made on the vertical direction tree ring stable carbon isotope ratio (delta13C) and tree ring width of Pinus sylvestris var. mongolica in northern Daxing' an Mountains of Northeast China, with the relationship between the vertical direction variations of the tree ring delta13C and tree ring width analyzed. In the whole ring of xylem, earlywood (EW) and bark endodermis, the delta13C all exhibited an increasing trend from the top to the base at first, with the maximum at the bottom of tree crown, and then, decreased rapidly to the minimum downward. The EW and late-wood (LW) had an increasing ratio of average tree ring width from the base to the top. The average annual sequence of the delta13C in vertical direction had an obvious reverse correspondence with the average annual sequence of tree ring width, and had a trend comparatively in line with the average annual sequence of the tree ring width ratio of EW to LW above tree crown. The variance analysis showed that there existed significant differences in the sequences of tree ring delta13C and ring width in vertical direction, and the magnitude of vertical delta13C variability was basically the same as that of the inter-annual delta13C variability. The year-to-year variation trend of the vertical delta13C sequence was approximately identical. For each sample, the delta13C sequence at the same heights was negatively correlated with the ring width sequence, but the statistical significance differed with tree height.

[Responses of Pinus tabulaeformis forest ecosystem in North China to climate change and elevated CO2: a simulation based on BIOME-BGC model and tree-ring data].

Based on BIOME-BGC model and tree-ring data, a modeling study was conducted to estimate the dynamic changes of the net primary productivity (NPP) of Pinus tabulaeformis forest ecosystem in North China in 1952-2008, and explore the responses of the radial growth and NPP to regional climate warming as well as the dynamics of the NPP in the future climate change scenarios. The simulation results indicated the annual NPP of the P. tabulaeformis ecosystem in 1952-2008 fluctuated from 244.12 to 645.31 g C x m(-2) x a(-1), with a mean value of 418.6 g C x m(-2) x a(-1) The mean air temperature in May-June and the precipitation from previous August to current July were the main factors limiting the radial growth of P. tabulaeformis and the NPP of P. tabulaeformis ecosystem. In the study period, both the radial growth and the NPP presented a decreasing trend due to the regional warming and drying climate condition. In the future climate scenarios, the NPP would have positive responses to the increase of air temperature, precipitation, and their combination. The elevated CO2 would benefit the increase of the NPP, and the increment would be about 16.1% due to the CO2 fertilization. At both ecosystem and regional scales, the tree-ring data would be an ideal proxy to predict the ecosystem dynamic change, and could be used to validate and calibrate the process-based ecosystem models including BIOME-BGC.

[Responses of Pinus sylvestris var. mongolica radial growth to climate warming in Great Xing' an Mountins: a case study in Mangui].

Based on the theory and methodology of dendrochronology, the tree ring width chronology of Pinus sylvestris var. mongolica in Mangui of Great Xing' an Mountains was developed, and the relationships between the standardized tree ring width chronology and local climate factors (temperature and precipitation) as well as the effects of climate factors on the P. sylvestris var. mongolica radial growth were analyzed. In this region, the mean monthly temperature in April-August of current year was the main factor limiting the radial growth, and the increasing mean monthly temperature from April to August had negative effects to the radial growth. The simulation of the variations of the radial growth by the mean monthly temperature change in April-August showed that the radial growth of P. sylvestris var. mongolica would present a declining trend accompanied with the warmer and drier regional climate condition.

[Larix gmelinii tree-ring width chronology and its responses to climate change in Kuduer, Great Xing' an Mountains].

Based on the established tree-ring width chronology of Larix gmelinii in Kuduer, Great Xing' an Mountains, this paper analyzed the relationships between L. gmelinii tree-ring width chronology and related climatic variables, including air temperature, precipitation, and PDSI. In the study area, the L. gmelinii tree-ring width chronology was significantly negatively correlated with the air temperature in May and July (P<0.01), had no significant correlation with precipitation, but significantly positively correlated with the PDSI in June-August (P<0.05), suggesting that hydro-thermal variables had significant coupling effects to the radial growth of L. gmelinii in its growth season, particularly in May and July. The L. gmelinii tree-ring width chronology had significant correlations with large scale climatic regimes such as the Pacific Decadal Oscillation (PDO) in both low and high frequency variations, illustrating the significant effects of the remote oceanic climatic regimes to the local tree growth.

[Dendrochronology of Chinese pine in Mulan-Weichang, Hebei Province: a primary study].

Dendroclimatic methods were used to investigate the relationships between the growth of Chinese pine (Pinus tabulaeformis Carr.) and the climatic parameters in Mulan-Weichang of Hebei Province. The results showed that Chinese pine presented high sensitivity to climatic changes, and its earlywood width showed the highest sensitivity. There was a significant negative correlation between the tree-ring width chronology of Chinese pine and the air temperature in May-June. The precipitation and relative humidity in June had strong positive effects on the growth of earlywood, the precipitation from September to next September had significant positive effects on Chinese pine growth, and the relative humidity in winter more strongly affected the growth of latewood than of earlywood. There was a definite correlation between the tree-ring width chronology of Chinese pine and the large scale climate fluctuation. From 1951 to 2006, the increase of air temperature in study area was significant, and the sensitivity of Chinese pine to the variations of local temperature and precipitation decreased, presenting an inverse transforming trend with increasing temperature. Greater differences were observed between the reconstructed and observed data of mean temperature in May - June in a century scale, suggesting that the tree-ring growth of Chinese pine in study area had a greater fluctuation of sensitivity to the variation of climatic factors.