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• A rice Zeta family glutathione-S-transferase (OsGSTZ4) gene for Cd detoxification was investigated. • Heterologous expression of OsGSTZ4 in a yeast conferred cellular Cd tolerance. • CHH hypermethylation at a MITE transposable element was found to be inserted in the 5′-untranscribed region of OsGSTZ4. • Three 24-nt siRNAs derived from the TE were detected and was rapidly enriched under Cd stress. • This study helps understand the diversity of gene regulation via an epigenetic mechanism for rice adaptation to the environmental stress. Environmental contaminants such as cadmium (Cd) pose high risks to crop production and human health. The genetic basis for regulation of Cd stress-responsive genes for plant adaptation to adverse environments remains poorly understood. In this study, we characterized a rice Zeta family glutathione-S-transferase (OsGSTZ4) gene for Cd detoxification. Heterologous expression of OsGSTZ4 in a yeast (Saccharomyces cerevisiae) conferred cellular Cd tolerance. Transgenic rice overexpressing OsGSTZ4 improved plant growth, attenuated Cd-induced toxicity, and accumulated more Cd in roots. OsGSTZ4 transcription was rapidly induced 3 h after Cd exposure and then declined to the basal level. This was followed by (days after Cd treatment) by CHH hypermethylation (by 41.2 %) at a MITE (Miniature Inverted-repeat Transposable Element) transposable element (TE) inserted in the 5′-untranscribed region (UTR) (-1,722 ∼ -1,392 bp) of OsGSTZ4. Meanwhile, three 24-nt siRNAs derived from the TE (-1,722 ∼ -1,471 bp) were detected and was also rapidly enriched under Cd stress. To validate the possibility that Cd-induced change in OsGSTZ4 expression correlates with the siRNAs-involved CHH methylation through an RdDM (RNA-directed DNA methylation) pathway, genetic analyses were performed. We found that the CHH methylation at the promoter and transcript level of OsGSTZ4 were compromised in the osdrm2 (loss of function for CHH methylation) and osrdr2i (defective in RNA-dependent RNA polymerase 2) but did not change in other types of methyltransferases such as osmet1, ossdg714 or osros1. Promoter deletion analyses confirmed that the siRNA target sequences were essential for the proper expression of OsGSTZ4. Our studies reveal an unusual feedback mechanism by which the Cd-induced rapid OsGSTZ4 expression for Cd tolerance would interplay with the late CHH hypermethylation to silence the TE through the 24-nt siRNAs- and Osdrm2-mediated RdDM pathway, and help understand the diversity of gene regulation via an epigenetic mechanism for rice adaptation to the environmental stress. [ABSTRACT FROM AUTHOR]

We aimed to identify RNA N6-methyladenosine methylation associated genes in osteoarthritis (OA), and to explore possible regulatory mechanisms of these RNA methylation associated genes. Bioinformatics analyses, including differential expression analysis, functional enrichment analysis, verification analysis, and box plot analysis, were conducted based on different datasets from OA and non-OA patients. Gene expression at mRNA and protein levels was determined by quantitative reverse transcription PCR, western blot and immunofluorescence. Interleukin 1β (IL-1β)-treated SW1353 cells was used as cell model. Lentiviral vector was used for over-expression METTL3 in vitro. CCK-8 assay kit was used to determine cell viability and inflammatory cytokines (IL-1α, IL-6, IL-8, IL-10 and TNF-α) was detected using ELISA kits. Bioinformatics analysis showed that METTL3 expression was decreased in OA group, which was confirmed in clinical samples. Expression of METTL3 was also reduced in IL-1β-treated cells. Levels of inflammatory cytokines were obviously reduced in the METTL3 overexpression group, while IL-1β treatment reversed such decrease caused by METTL3 overexpression (p < 0.05). Both METTL3 overexpression and IL-1β treatment promoted expression of p65 protein and p-ERK (p < 0.01). Additionally, increased expression of MMP1 and MMP3 , and decreased expression of MMP13 , TIMP-1 , and TIMP-2 at both mRNA and protein levels were observed in the METTL3 overexpression group when compared with the control group (p < 0.01). Expression of m6A methylation gene METTL3 was reduced in OA. METTL3 is involved in OA probably by regulating the inflammatory response. METTL 3 overexpression may affect extracellular matrix degradation in OA by adjusting the balance between TIMPs and MMPs. • METTL3 and YTHDC2 were identified as m6A methylation-related genes in OA. • METTL3 may be involved in OA by regulating the inflammatory response. • METTL3 overexpression may affect ECM degradation in OA. [ABSTRACT FROM AUTHOR]

Singlet oxygen (¹O2) has a very short half-life of 10-5 s; however, it is a strong oxidant that causes growth arrest and necrotic lesions on plants. Its signaling pathway remains largely unknown. The Arabidopsis flu (fluorescent) mutant accumulates a high level of ¹O2 and shows drastic changes in nuclear gene expression. Only two plastid proteins, EX1 (executer 1) and EX2 (executer 2), have been identified in the singlet oxygen signaling. Here, we found that the transcription factor abscisic acid insensitive 4 (ABI4) binds the promoters of genes responsive to ¹O2-signals. Inactivation of the ABI4 protein in the flu/abi4 double mutant was sufficient to compromise the changes of almost all ¹O2-responsive-genes and rescued the lethal phenotype of flu grown under light/dark cycles, similar to the flu/ex1/ex2 triple mutant. In addition to cell death, we reported for the first time that ¹O2 also induces cell wall thickening and stomatal development defect. Contrastingly, no apparent growth arrest was observed for the flu mutant under normal light/dim light cycles, but the cell wall thickening (doubled) and stomatal density reduction (by two-thirds) still occurred. These results offer a new idea for breeding stress tolerant plants. [ABSTRACT FROM AUTHOR]

Abstract: Dietary conjugated linoleic acid (CLA) has been investigated for its beneficial effects on disease prevention and treatment, and now obesity is one of the most perspective researching highlights. In a variety of experimental models, the results of studies on the effects of CLA on food intakes are somewhat inconsistent. Our experiment was conducted to extend these observations to hypothalamus and other regions within the central nervous system so that the mechanism of the actions of CLA might be more easily elucidated. In the experiment, a permanent cannula was inserted into the lateral ventricle of each rat. For the experiment, animals received intracerebroventricular injections of either 150nmol (n =16) CLA, or LA as non-conjugated control, or normal saline as vehicle. Hypothalamus and blood samples were collected at the 2nd, 4th, 8th, and 14th day. The results show that CLA in cerebral ventricle can inhibit food intake of experimented rats and this inhibition is related with the decreased expression of neuropeptides Y (NPY) and agouti-related protein (AgRP). The circulating leptin level was also increased by this tentative treatment (2.94±0.71 versus 1.18±0.18ng/ml). However, the glucose metabolism was not affected by ICV CLA. It is concluded that CLA in brain can inhibit the appetite of rats through the mechanism of decreasing the expression of NPY and AgRP. [Copyright &y& Elsevier]

Abstract: Hymeniacidon sinapium (De Laubenfels, 1930) (Demospongiae, Halichondrida, Halichondriidae) collected from China''s Yellow Sea has been a model sponge species for extensive studies of in vitro cultures of sponge cells and explants in our group since 2002. To better understand its reproductive cycle, the aim of this study is to elucidate the temporal changes in microbial community, the spiculogenesis activity (in terms of silicatein gene expression) and the stress response (in terms of hsp70 gene expression) during its annual life cycle. Histological studies by light microscopy revealed that H. sinapium is a characteristic seasonal species with four distinctive developmental stages of resuscitation, bloom, decline and dormancy during its annual life cycle. The sexual reproductive processes were observed from August to October (summer), with all the reproductive elements (oocytes, sperm cysts, embryos and larvae) documented. There is no direct correlation between seawater temperature and gametogenesis. The gene expression of silicatein and hsp70 was investigated by quantitative real-time RT-PCR during its annual life cycle. Silicatein expression correlated with the histogenesis and reached the highest value in late July (bloom stage). While hsp70 expression correlated with the seawater temperature and also reached the highest value at the same time. We hypothesize that after reaching the maximum biomass growth, sponge should adjust energy distribution to meet the need of gametogenesis and embryogenesis in the reproductive season. Bacterial community variability in a life cycle ranged from 18% to 98% (dice similarity of each two samples) using DGGE, and formed four distinctive clusters consistent with seasons. After sequencing, twelve typical bands from DGGE were compared to GenBank and basically clustered into five phyla: Actinobacteria, α-Proteobacteria, γ-Proteobacteria, Bacteroidetes and Cyanobacteria. This study reported, for the first time, high temporal variability in silicatein, hsp70 and bacterial community during the annual life cycle of H. sinapium. This knowledge is significant for the development of sponge explants culture under controlled laboratory conditions and large-scale sponge seed-rearing technology. [Copyright &y& Elsevier]