CeO / 中国生物化学与分子生物学报

Drought is a common limiting factor affecting rice yield and quality. Cerium oxide nanoparticles(nanoceria) have been widely reported to improve crop stress tolerance. However, the effects and mechanisms of nanoceria on rice drought tolerance are still unknown. The aim of this study is to investigate whether nanoceria can improve rice drought tolerance by modulating reactive oxygen species(ROS) homeostasis and nitric oxide(NO) levels. Our results showed that compared with no-nanoparticle treatment, nanoceria significantly increased the fresh weight of rice seedlings under drought stress(19%, P < 0. 05). Also, under drought stress, the ROS level of rice leaves treated with nanoceria was significantly lower(82%, P < 0. 05) than leaves treated with buffer. The leaf NO level after nanoceria treatment, however, is significantly higher(46%, P < 0. 05) than that with no-nanoparticle treatment under drought stress. Moreover, compared with control plants, nanoceria maintained better membrane integrity in rice leaf cells under drought stress, showing a 70% decrease(P < 0. 05) in dead leaf cells. This study explores the mechanisms underlying nanoceria’s improved rice drought tolerance by affecting ROS and NO levels, which not only further enriches our knowledge about the interaction between nanoparticles and crops under abiotic stress but also gives more support on the sustainable development of nano-enabled agriculture.

Association analysis between SNPs in LATS1 and LATS2 and non-cardia gastric cancer.

BACKGROUND: Many studies have found that large tumor suppressor kinase 1 (LATS1) and LATS2 play important roles in many diseases, but studies have been rare on the relationship between these genes and non-cardia gastric cancer (GC). We performed a case-control association study to investigate the associations between single nucleotide polymorphisms (SNPs) in LATS1 and LATS2 genes and Helicobacter pylori (H. pylori) infection as well as the risk of non-cardia GC. METHODS: First, H. pylori infection was determined by the serological test using enzyme-linked immunoassay. Then genotyping of SNPs was performed for 808 samples by the Taqman method. Finally, unconditional logistic regression was used to calculate the odds ratios (ORs) and 95% confidence intervals (CIs), adjusted for age and gender, for the association of each SNP with the infection of H. pylori, the risk of non-cardia gastric cancer, as well as the expression of LATS1 and LATS2 proteins in non-cardia GC tissues, using the codominant, dominant, recessive, overdominant, and log-additive inheritance models, respectively. RESULTS: The statistical results showed that LATS2 rs9552315 was associated with H. pylori infection, and the CC + CT genotype could reduce the risk of H. pylori infection (odds ratio [OR]: 0.549, 95% confidence interval [CI]: 0.339-0.881, P < 0.05) compared with the TT genotype in a dominant model. LATS1 rs9393175 was associated with the risk of non-cardia GC, and the AG genotype reduced the risk of non-cardia GC (OR: 0.702, 95% CI: 0.516-0.952, P < 0.05) compared with the GG + AA genotype in an overdominant model. LATS2 rs9509492 was associated with the risk of GC in an log-additive model. No associations were found between five SNPs and expression of LATS1 and LATS2 proteins in non-cardia GC tissue. CONCLUSIONS: LATS2 rs9552315 CT genotype may be a protective factor against infection of H. pylori. LATS1 rs9393175 AG genotype and LATS2 rs9509492 GG genotype may be protective factors for non-cardia GC.

Impeding the interaction between Nur77 and p38 reduces LPS-induced inflammation.

Sepsis, a hyperinflammatory response that can result in multiple organ dysfunctions, is a leading cause of mortality from infection. Here, we show that orphan nuclear receptor Nur77 (also known as TR3) can enhance resistance to lipopolysaccharide (LPS)-induced sepsis in mice by inhibiting NF-κB activity and suppressing aberrant cytokine production. Nur77 directly associates with p65 to block its binding to the κB element. However, this function of Nur77 is countered by the LPS-activated p38α phosphorylation of Nur77. Dampening the interaction between Nur77 and p38α would favor Nur77 suppression of the hyperinflammatory response. A compound, n-pentyl 2-[3,5-dihydroxy-2-(1-nonanoyl) phenyl]acetate, screened from a Nur77-biased library, blocked the Nur77-p38α interaction by targeting the ligand-binding domain of Nur77 and restored the suppression of the hyperinflammatory response through Nur77 inhibition of NF-κB. This study associates the nuclear receptor with immune homeostasis and implicates a new therapeutic strategy to treat hyperinflammatory responses by targeting a p38α substrate to modulate p38α-regulated functions.

Orphan nuclear receptor TR3 acts in autophagic cell death via mitochondrial signaling pathway.

Autophagy is linked to cell death, yet the associated mechanisms are largely undercharacterized. We discovered that melanoma, which is generally resistant to drug-induced apoptosis, can undergo autophagic cell death with the participation of orphan nuclear receptor TR3. A sequence of molecular events leading to cellular demise is launched by a specific chemical compound, 1-(3,4,5-trihydroxyphenyl)nonan-1-one, newly acquired from screening a library of TR3-targeting compounds. The autophagic cascade comprises TR3 translocation to mitochondria through interaction with the mitochondrial outer membrane protein Nix, crossing into the mitochondrial inner membrane through Tom40 and Tom70 channel proteins, dissipation of mitochondrial membrane potential by the permeability transition pore complex ANT1-VDAC1 and induction of autophagy. This process leads to excessive mitochondria clearance and irreversible cell death. It implicates a new approach to melanoma therapy through activation of a mitochondrial signaling pathway that integrates a nuclear receptor with autophagy for cell death.

Magnifying chromoendoscopy combined with immunohistochemical staining for early diagnosis of gastric cancer.

AIM: To assess the diagnostic value of using magnifying chromoendoscopy combined with immunohistochemical staining of proliferating cell nuclear antigen (PCNA) and p53 in the detection of gastric precancerous lesions. METHODS: Ninety-five patients who were treated for abdominal discomfort, abdominal pain, bloating, and acid reflux at our hospital from January 2010 to December 2011 were included in the study. An ordinary gastroscopic procedure was initially performed to select the lesions. All subjects underwent magnifying chromoendoscopy to observe morphological changes of gastric pits. Biopsies were then taken from each area of interest and sent for pathological examination and detection of PCNA and p53 expression by immunohistochemistry. An immunoreactivity score for each lesion was calculated. Based on immunoreactivity scores, immunohistochemical staining was then considered. RESULTS: Compared to intestinal metaplasia, gastric pits were more diverse in size, more irregular in shape, and more disorderly in arrangement in moderate and severe dysplasia. PCNA and p53 expression was significantly higher in precancerous lesions (intestinal metaplasia and dysplasia) than in chronic gastritis. PCNA expression showed an upward trend in types A-F pits. The number of cases that showed strong PCNA positivity increased significantly with an increase in the severity of lesions. Rank sum test for independent samples showed that p53 expression was significantly higher in types E and F pits than in types A-D pits (H = 33.068, P = 0.000). Rank sum test for independent samples showed that PCNA expression was significantly higher in types E and F pits than in types A-D pits (H = 31.791, P = 0.001). CONCLUSION: The presence of types E and F pits, in which p53 and PCNA are highly expressed, is highly suggestive of the occurrence of early cancer, and patients developing these changes should be closely followed.