Nimbolide ameliorates the streptozotocin-induced diabetic retinopathy in rats through the inhibition of TLR4/NF-κB signaling pathway

BackgroundDiabetic retinopathy (DR) is a common problem in the diabetic patients due to the high blood glucose level. DR affects more number of diabetic patients worldwide with irreversible vision loss.ObjectiveThe current investigation was focused to reveal the therapeutic actions of nimbolide against the streptozotocin (STZ)-provoked DR in rats through inhibition of TLR4/NF-κB pathway.MethodologyDR was provoked to the rats through administering a single dose of STZ (60 mg/kg) intraperitoneally. The DR rats were then supplemented with the 50 mg/kg of nimbolide for 60 days. The bodyweight and blood glucose level was measured using standard methods. The lipid profiles (cholesterol, TG, LDL, and HDL), inflammatory markers, and antioxidants level was detected using respective kits. The level of MCP-1, VEGF, and MMP-9 was quantified using kits. The morphometric analysis of retinal tissues were done. The mRNA expressions of target genes were studied using RT-PCR assay.ResultsNimbolide treatment effective decreased the food intake and blood glucose, and improved the bodyweight of STZ-provoked animals. The levels of pro-inflammatory mediators, cholesterol, TG, LDL, and HDL, MCP-1, VEGF, and MMP-9 was remarkably suppressed by the nimbolide treatment. Nimbolide also improved the antioxidants, retinal thickness and cell numbers. The TLR4/NF-κB pathway was appreciably inhibited by the nimbolide.ConclusionOverall, our findings demonstrated that the nimbolide attenuated the STZ-provoked DR in rats through inhibiting the TLR4/NF-κB pathway.     

Climatic‐niche evolution with key morphological innovations across clades within Scutiger boulengeri (Anura: Megophryidae)

The studies of climatic‐niche shifts over evolutionary time accompanied by key morphological innovations have attracted the interest of many researchers recently. We applied ecological niche models (ENMs), ordination method (environment principal component analyses; PCA‐env), combined phylogenetic comparative methods (PCMs), and phylogenetic generalized least squares (PGLS) regression methods to analyze the realized niche dynamics and correspondingly key morphological innovations across clades within Scutiger boulengeri throughout their distributions in Qinghai–Tibet Plateau (QTP) margins of China. Our results show there are six clades in S. boulengeri and obvious niche divergences caused by niche expansion in three clades. Moreover, in our system, niche expansion is more popular than niche unfilling into novel environmental conditions. Annual mean temperature, annual precipitation, and precipitation of driest month may contribute to such a shift. In addition, we identified several key climatic factors and morphological traits that tend to be associated with niche expansion in S. boulengeri clades correspondingly. We found phenotypic plasticity [i.e., length of lower arm and hand (LAHL), hind‐limb length (HLL), and foot length (FL)] and evolutionary changes [i.e., snout–vent length (SVL)] may together contribute to niche expansion toward adapting novel niche, which provides us a potential pattern of how a colonizing toad might seed a novel habitat to begin the process of speciation and finally adaptive radiation. For these reasons, persistent phylogeographic divisions and accompanying divergences in niche occupancy and morphological adaption suggest that for future studies, distinct genetic structure and morphological changes corresponding to each genetic clade should be included in modeling niche evolution dynamics, but not just constructed at the species level.     

Identification and validation of reference genes for Populus euphratica gene expression analysis during abiotic stresses by quantitative real‐time PCR

Populus euphratica is the only arboreal species that is established in the world's largest shifting‐sand desert in China and is well‐adapted to the extreme desert environment, so it is widely considered a model system for researching into abiotic stress resistance of woody plants. However, few P. euphratica reference genes (RGs) have been identified for quantitative real‐time polymerase chain reaction (qRT‐PCR) until now. Validation of suitable RGs is essential for gene expression normalization research. In this study, we screened 16 endogenous candidate RGs in P. euphratica leaves in six abiotic stress treatments, including abscisic acid (ABA), cold, dehydration, drought, short‐duration salt (SS) and long‐duration salt (LS) treatments, each with 6 treatment gradients. After calculation of PCR efficiencies, three different software tools, NormFinder, geNorm and BestKeeper, were employed to analyze the qRT‐PCR data systematically, and the outputs were merged by means of a non‐weighted unsupervised rank aggregation method. The genes selected as optimal for gene expression analysis of the six treatments were RPL17 (ribosomal protein L17) in ABA, EF1α (elongation factor‐1 alpha) in cold, HIS (histone superfamily protein H3) in dehydration, GIIα in drought and SS, and TUB (tubulin) in LS. The expression of 60S (the 60S ribosomal protein) varied the least during all treatments. To illustrate the suitability of these RGs, the relative quantifications of three stress‐inducible genes, PePYL1, PeSCOF‐1 and PeSCL7 were investigated with different RGs. The results, calculated using qBasePlus software, showed that compared with the least‐appropriate RGs, the expression profiles normalized by the recommended RGs were closer to expectations. Our study provided an important RG application guideline for P. euphratica gene expression characterization.     

Specific expression of the human voltage-gated proton channel Hv1 in highly metastatic breast cancer cells, promotes tumor progression and metastasis

The newly discovered human voltage-gated proton channel Hv1 is essential for proton transfer, which contains a voltage sensor domain (VSD) without a pore domain. We report here for the first time that Hv1 is specifically expressed in the highly metastatic human breast tumor tissues, but not in poorly metastatic breast cancer tissues, detected by immunohistochemistry. Meanwhile, real-time RT-PCR and immunocytochemistry showed that the expression levels of Hv1 have significant differences among breast cancer cell lines, MCF-7, MDA-MB-231, MDA-MB-468, MDA-MB-453, T-47D and SK-BR-3, in which Hv1 is expressed at a high level in highly metastatic human breast cancer cell line MDA-MB-231, but at a very low level in poorly metastatic human breast cancer cell line MCF-7. Inhibition of Hv1 expression in the highly metastatic MDA-MB-231 cells by small interfering RNA (siRNA) significantly decreases the invasion and migration of the cells. The intracellular pH of MDA-MB-231 cells down-regulated Hv1 expression by siRNA is obviously decreased compared with MDA-MB-231 with the scrambled siRNA. The expression of matrix metalloproteinase-2 and gelatinase activity in MDA-MB-231 cells suppressed Hv1 by siRNA were reduced. Our results strongly suggest that Hv1 regulates breast cancer intracellular pH and exacerbates the migratory ability of metastatic cells.     

Human amelogenin up-regulates osteogenic gene expression in human bone marrow stroma cells

Extracts of enamel matrix proteins are used to regenerate periodontal tissues. Amelogenin, the most abundant enamel protein, plays an important role in the regeneration of these tissues. However, the molecular mechanisms by which amelogenin contributes to periodontal regeneration remain unknown. Using primary human bone marrow stroma cells (hBMSCs) transduced with lentivirus encoding human amelogenin (hAm), we performed genome-wide expression profiling to analyze the effects of hAm transduction on the regulation of genes involved in osteogenic differentiation. Our results revealed that BMP-2, BMP-6, OPN and VEGFC were up-regulated. These results suggest that hAm may be a key element in regulating hBMSCs osteogenic differentiation.     

Synthesis, crystal structure and magnetic properties of cubane and linear trinuclear nickel complexes formed by 3,5-dichloro-2-hydroxybenzylaminoacetic acid

The reaction of Ni(ClO₄)₂·6H₂O with 3,5-dichloro-2-hydroxy-benzylaminoacetic acid (H₂dchaa), NaN₃ and triethylamine in methanol solution or water solution under solvothermal methods leads to the formation of two completely different Ni^II compounds: [HN(C₂H₅)₃]₈·[Ni₄(dchaa)₄(N₃)₄]₂ (1) and [HN(C₂H₅)₃]₂·[Ni₃(dchaa)₄(H₂O)₄]₂·(H₂O)₂ (2). The complexes 1 and 2 have been characterized by elemental analyses, IR spectra and single-crystal X-ray diffraction. Structure analyses reveal that complex 1 is a cubane cluster, while the complex 2 is a linear trinuclear cluster. The magnetic investigation shows that complexes 1 and 2 exhibit a ferromagnetic coupling between Ni^II ions. Ac susceptibilities of 1 and 2 reveal no frequency-dependent out-of-phase signals and the corresponding magnetic properties were discussed.     

Genome sequence of Agrobacterium tumefaciens strain F2, a bioflocculant-producing bacterium

Agrobacterium tumefaciens F2 is an efficient bioflocculant-producing bacterium. But the genes related to the metabolic pathway of bioflocculant biosynthesis in strain F2 are unknown. We present the draft genome of A. tumefaciens F2. It could provide further insight into the biosynthetic mechanism of polysaccharide-like bioflocculant in strain F2.     

Complete genome sequence of seawater bacterium Glaciecola nitratireducens FR1064(T)

Glaciecola nitratireducens strain FR1064(T) was isolated from seawater and described as a new species by Baik et al. in 2006. The genome size is about 1.01 to 1.26 Mb smaller than two reported Glaciecola genomes, indicating the gain or loss of large genome segments in the evolution of Glaciecola strains.     

Mutant p53 disrupts role of ShcA protein in balancing Smad protein-dependent and -independent signaling activity of transforming growth factor-β (TGF-β)

Biomarkers are lacking for identifying the switch of transforming growth factor-β (TGF-β) from tumor-suppressing to tumor-promoting. Mutated p53 (mp53) has been suggested to switch TGF-β to a tumor promoter. However, we found that mp53 does not always promote the oncogenic role of TGF-β. Here, we show that endogenous mp53 knockdown enhanced cell migration and phosphorylation of ERK in DU145 prostate cancer cells. Furthermore, ectopic expression of mp53 in p53-null PC-3 prostate cancer cells enhanced Smad-dependent signaling but inhibited TGF-β-induced cell migration by down-regulating activated ERK. Reactivation of ERK by the expression of its activator, MEK-1, restored TGF-β-induced cell migration. Because TGF-β is known to activate the MAPK/ERK pathway through direct phosphorylation of the adaptor protein ShcA and MAPK/ERK signaling is pivotal to tumor progression, we investigated whether ShcA contributed to mp53-induced ERK inhibition and the conversion of the role of TGF-β during carcinogenesis. We found that mp53 expression led to a decrease of phosphorylated p52ShcA/ERK levels and an increase of phosphorylated Smad levels in a panel of mp53-expressing cancer cell lines and in mammary glands and tumors from mp53 knock-in mice. By manipulating ShcA levels to regulate ERK and Smad signaling in human untransformed and cancer cell lines, we showed that the role of TGF-β in regulating anchorage-dependent and -independent growth and migration can be shifted between growth suppression and migration promotion. Thus, our results for the first time suggest that mp53 disrupts the role of ShcA in balancing the Smad-dependent and -independent signaling activity of TGF-β and that ShcA/ERK signaling is a major pathway regulating the tumor-promoting activity of TGF-β.     

Abscisic acid plays an important role in the regulation of strawberry fruit ripening

The plant hormone abscisic acid (ABA) has been suggested to play a role in fruit development, but supporting genetic evidence has been lacking. Here, we report that ABA promotes strawberry (Fragaria ananassa) fruit ripening. Using a newly established Tobacco rattle virus-induced gene silencing technique in strawberry fruit, the expression of a 9-cis-epoxycarotenoid dioxygenase gene (FaNCED1), which is key to ABA biosynthesis, was down-regulated, resulting in a significant decrease in ABA levels and uncolored fruits. Interestingly, a similar uncolored phenotype was observed in the transgenic RNA interference (RNAi) fruits, in which the expression of a putative ABA receptor gene encoding the magnesium chelatase H subunit (FaCHLH/ABAR) was down-regulated by virus-induced gene silencing. More importantly, the uncolored phenotype of the FaNCED1-down-regulated RNAi fruits could be rescued by exogenous ABA, but the ABA treatment could not reverse the uncolored phenotype of the FaCHLH/ABAR-down-regulated RNAi fruits. We observed that down-regulation of the FaCHLH/ABAR gene in the RNAi fruit altered both ABA levels and sugar content as well as a set of ABA- and/or sugar-responsive genes. Additionally, we showed that exogenous sugars, particularly sucrose, can significantly promote ripening while stimulating ABA accumulation. These data provide evidence that ABA is a signal molecule that promotes strawberry ripening and that the putative ABA receptor, FaCHLH/ABAR, is a positive regulator of ripening in response to ABA.