Shizhi Wang

FAS rs2234767 and rs1800682 polymorphisms jointly contributed to risk of colorectal cancer by affecting SP1/STAT1 complex recruitment to chromatin

FAS rs2234767 (−1377 G>A), rs1800682 (−670 A>G) and FASLG rs763110 (−844 C>T) promoter polymorphisms can influence transcriptional activities of the genes and thus multiple tumors susceptibility. To investigate their association with risk of colorectal cancer (CRC), the three SNPs were genotyped in 878 cases and 884 controls and the results showed that the FAS rs2234767 and rs1800682 were in a high linkage disequilibrium (LD) with each other (D’ = 0.994) and jointly contributed to an increased risk of CRC (without vs. with rs2234767 GG/rs1800682 AA genotypes, adjusted OR = 1.30, 95% CI = 1.05 − 1.61). In vivo ChIP assays evaluated the effect of rs2234767 and rs1800682 on recruitment of SP1 and STAT1, respectively, to chromatin. The results showed SP1 interacting specifically with STAT1 recruited to their respective motifs for transcriptional activation. The mutant alleles rs2234767 A and rs1800682 G jointly affected coupled SP1 and STAT1 recruitment to chromatin. The interplay between SP1 and STAT1 was critical for the functional outcome of rs2234767 and rs1800682 in view of their high LD. In conclusion, the FAS rs2234767 and rs1800682 polymorphisms were in high LD with each other, and they jointly contributed to an increased risk of CRC by altering recruitment of SP1/STAT1 complex to the FAS promoter for transcriptional activation.

miR-107 regulates tumor progression by targeting NF1 in gastric cancer

Our previous genome-wide miRNA microarray study revealed that miR-107 was upregulated in gastric cancer (GC). In this study we aimed to explore its biological role in the pathogenesis of GC. Integrating in silico prediction algorithms with western blotting assays revealed that miR-107 inhibition enhanced NF1 (neurofibromin 1) mRNA and protein levels, suggesting that NF1 is one of miR-107 targets in GC. Luciferase reporter assay revealed that miR-107 suppressed NF1 expression by binding to the first potential binding site within the 3′-UTR of NF1 mRNA. mRNA stable assay indicated this binding could result in NF1 mRNA instability, which might contribute to its abnormal protein expression. Functional analyses such as cell growth, transwell migration and invasion assays were used to investigate the role of interaction between miR-107 and its target on GC development and progression. Moreover, We investigated the association between the clinical phenotype and the status of miR-107 expression in 55 GC tissues, and found the high expression contributed to the tumor size and depth of invasion. The results exhibited that down regulation of miR-107 opposed cell growth, migration, and invasion, whereas NF1 repression promoted these phenotypes. Our findings provide a mechanism by which miR-107 regulates NF1 in GC, as well as highlight the importance of interaction between miR-107 and NF1 in GC development and progression.

MicroRNA-1228* inhibit apoptosis in A549 cells exposed to fine particulate matter

Studies have reported associations between fine particulate matter (PM2.5) and respiratory disorders; however, the underlying mechanism is not completely clear owing to the complex components of PM2.5. microRNAs (miRNAs) demonstrate tremendous regulation to target genes, which are sensitive to exogenous stimulation, and facilitate the integrative understood of biological responses. Here, significantly modulated miRNA were profiled by miRNA microarray, coupled with bioinformatic analysis; the potential biological function of modulated miRNA were predicted and subsequently validated by cell-based assays. Downregulation of miR-1228-5p (miR-1228*) expression in human A549 cells were associated with PM2.5-induced cellular apoptosis through a mitochondria-dependent pathway. Further, overexpression of miR-1228* rescued the cellular damages induced by PM2.5. Thus, our results demonstrate that PM2.5-induced A549 apoptosis is initiated by mitochondrial dysfunction and miR-1228* could protect A549 cells against apoptosis. The involved pathways and target genes might be used for future mechanistic studies.

An acetyl-L-carnitine switch on mitochondrial dysfunction and rescue in the metabolomics study on aluminum oxide nanoparticles

BackgroundDue to the wide application of engineered aluminum oxide nanoparticles and increased aluminum containing particulate matter suspending in air, exposure of human to nano-scale aluminum oxide nanoparticles (Al2O3 NPs) is becoming inevitable.MethodsIn the present study, RNA microarray coupled with metabolomics analysis were used to uncover mechanisms underlying cellular responses to Al2O3 NPs and imply the potential rescue.ResultsWe found that Al2O3 NPs significantly triggered down-regulation of mitochondria-related genes located in complex I, IV and V, which were involved in oxidative phosphorylation and neural degeneration pathways, in human bronchial epithelial (HBE) cells. Subsequent cell- and animal- based assays confirmed that Al2O3 NPs caused mitochondria-dependent apoptosis and oxidative stress either in vitro or in vivo, which were consistent with the trends of gene regulation. To rescue the Al2O3 NPs induced mitochondria dysfunction, disruption of small molecular metabolites of HBE were profiled using metabolomics analysis, which facilitates identification of potential antagonizer or supplement against nanoparticle-involved damages. Supplementation of an antioxidant, acetyl-L-carnitine, completely or partially restored the Al2O3 NPs modulated gene expression levels in mitochondrial complex I, IV and V. It further reduced apoptosis and oxidative damages in both Al2O3 NPs treated HBE cells and animal lung tissues.ConclusionThus, our results demonstrate the potential mechanism of respiratory system damages induced by Al2O3 NPs. Meanwhile, based on the metabolomics profiling, application of acetyl-L-carnitine is suggested to ameliorate mitochondria dysfunction associated with Al2O3 NPs.

Sex-Dependent Depression-Like Behavior Induced by Respiratory Administration of Aluminum Oxide Nanoparticles

Ultrafine aluminum oxide, which are abundant in ambient and involved occupational environments, are associated with neurobehavioral alterations. However, few studies have focused on the effect of sex differences following exposure to environmental Al2O3 ultrafine particles. In the present study, male and female mice were exposed to Al2O3 nanoparticles (NPs) through a respiratory route. Only the female mice showed depression-like behavior. Although no obvious pathological changes were observed in mice brain tissues, the neurotransmitter and voltage-gated ion channel related gene expression, as well as the small molecule metabolites in the cerebral cortex, were differentially modulated between male and female mice. Both mental disorder-involved gene expression levels and metabolomics analysis results strongly suggested that glutamate pathways were implicated in sex differentiation induced by Al2O3 NPs. Results demonstrated the potential mechanism of environmental ultrafine particle-induced depression-like behavior and the importance of sex dimorphism in the toxic research of environmental chemicals.

Integrative functional transcriptomic analyses implicate specific molecular pathways in pulmonary toxicity from exposure to aluminum oxide nanoparticles

Abstract Gene expression profiling has developed rapidly in recent years and it can predict and define mechanisms underlying chemical toxicity. Here, RNA microarray and computational technology were used to show that aluminum oxide nanoparticles (Al2O3 NPs) were capable of triggering up-regulation of genes related to the cell cycle and cell death in a human A549 lung adenocarcinoma cell line. Gene expression levels were validated in Al2O3 NPs exposed A549 cells and mice lung tissues, most of which showed consistent trends in regulation. Gene-transcription factor network analysis coupled with cell- and animal-based assays demonstrated that the genes encoding PTPN6, RTN4, BAX and IER play a role in the biological responses induced by the nanoparticle exposure, which caused cell death and cell cycle arrest in the G2/S phase. Further, down-regulated PTPN6 expression demonstrated a core role in the network, thus expression level of PTPN6 was rescued by plasmid transfection, which showed ameliorative effects of A549 cells against cell death and cell cycle arrest. These results demonstrate the feasibility of using gene expression profiling to predict cellular responses induced by nanomaterials, which could be used to develop a comprehensive knowledge of nanotoxicity.

Role of microRNA-4516 involved autophagy associated with exposure to fine particulate matter

Metals are vital toxic components of fine particulate matter (PM2.5). Cellular responses to exposure to PM2.5 or PM metal components remain unknown. Post-transcriptional profiling and subsequent cell- and individual-based assays implied that the metal ion-binding miR-4516/RPL37/autophagy pathway could play a critical role in cellular responses to PM2.5 and PM metal stresses. miR-4516 was up-regulated in A549 cells exposed to PM2.5 and in the serum of individuals living in a city with moderate air pollution. The expression levels of the miR-4516 target genes, namely, RPL37 and UBA52, were involved in ribosome function and inhibited by exposure to PM2.5 and PM metal components. Autophagy in A549 cells was induced by PM2.5 exposure as a response to decreased RPL37 expression. Moreover, enhanced miR-4516 expression was positively correlated with the augmentation of the internal burden of aluminum and lead in individuals living in a city with moderate air pollution. Hereby, the miR-4516/RPL37/autophagy pathway may represent a novel mechanism that mediates responses to PM metal components.

PSCA rs2294008 polymorphism contributes to the decreased risk for cervical cancer in a Chinese population

Recently, three genome-wide association studies have identified the PSCA (prostate stem cell antigen) rs2294008 polymorphism (C > T) associated with susceptibility to gastric cancer, bladder cancer, and duodenal ulcers, highlighting its critical role in disease pathogenesis. Given PSCA is reported to be overexpressed in cervical cancer and the rs2294008 can influence PSCA transcription, we aimed to determine the role of rs2294008 in susceptibility to cervical cancer. The genotyping was performed in the 1126 cases and 1237 controls. Our results showed the rs2294008 TT genotype significantly associated with a reduced risk of cervical cancer (adjusted OR = 0.55, 95% CI = 0.38–0.79; recessive model). Stratified analyses revealed that the association was restricted to the subgroups of age > 49 years, parity ≤ 1, abortion and early-stage cervical cancer. Immunohistochemistry assay showed the individuals carrying the TT genotype having lower PSCA expression than those with CC/CT genotypes. In summary, the PSCA rs2294008 polymorphism may serve as a biomarker of cervical cancer, particularly of early-stage cervical cancer.

Role of astrocyte activation in fine particulate matter-enhancement of existing ischemic stroke in Sprague-Dawley male rats

ABSTRACT Exposure to particulate matter (PM) with an aerodynamic diameter of less than 2.5 μm (PM2.5) is associated with increased risk of ischemic stroke, but potential neurotoxic mechanisms remain to be determined. In this study, adult male Sprague- Dawley (SD) rats were divided into four groups as follows: control (CON), PM2.5 exposure (PM alone), ischemic stroke (IS), and ischemic stroke and PM2.5 (IS-PM). Ischemic stroke groups were prepared by middle cerebral artery occlusion (MCAO), and neurobehavior was assessed daily for 7 consecutive days. The control group was administered intranasally 20 μl PBS, while PM2.5 alone was given as 20 μl of PM2.5 (10 mg/ml) intranasal daily for 7 consecutive days. The spontaneous locomotion and exploratory behavior of rats were assessed by the open field test. Cells positive for glial fibrillary acidic protein (GFAP) and inducible nitric oxide synthase (iNOS) were determined for astrocyte activation and inflammatory reactions. Neuronal edema and pyknosis in the cerebral cortex, hippocampus, and midbrain were observed in IS groups with or without PM2.5 treatment. Astrocyte activity was enhanced, whereas spontaneous locomotion and exploratory movements decreased in the IS-PM group. Data demonstrated that astrocytes activation and inflammatory reactions may play a role in IS and that exposure to PM2.5 may aggravate the neurobehavioral alterations observed in rats suffering from IS.

HOTAIR rs7958904 polymorphism is associated with increased cervical cancer risk in a Chinese population

Previously, we have identified single nucleotide polymorphisms (SNPs) rs7958904 and rs4759314 in long non-coding RNA HOX transcript antisense RNA (HOTAIR) were significantly associated with risk of colorectal and gastric cancer, respectively. Here, we aimed to investigate the association between HOTAIR SNPs and cervical cancer (CC) susceptibility. A total of 1209 cases and 1348 controls were enrolled for association study and genotyped with TaqMan allelic discrimination method. The Cancer Genome Atlas (TCGA) database was utilized for in vivo analysis of allele-specific HOTAIR expression. MTT assay was employed for evaluation of allele-specific cell proliferation. The rs7958904 CC genotype was related to an increased risk of cervical cancer compared with the GG/GC genotypes (OR = 1.57, 95% CI = 1.10–2.25). TCGA database showed the CC tissues with rs7958904 CC genotype had higher HOTAIR expression than those with GG genotype (P = 0.046). MTT assay demonstrated a growth-promoting role of rs7958904 C allele on CC cells. Further functional studies on the effect of rs7958904 on biological behavior of CC cells are needed to confirm and extend our findings. In conclusion, HOTAIR rs7958904 might influence CC susceptibility through modulation of CC cell proliferation, and could serve as a diagnostic biomarker.