Heterogeneous nuclear ribonucleoprotein E1 regulates protein disulphide isomerase translation in oxidized low-density lipoprotein-activated endothelial cells

AIMS

Endothelium-derived protein disulphide isomerase (PDI) is required for thrombus formation in vivo. But, how to control PDI overproduction in oxidized low-density lipoprotein (oxLDL)-activated vascular endothelial cells (VECs) is not well understood. In this study, we try to answer this question using our newly identified activator of mTOC1 3-benzyl-5-((2-nitrophenoxy) methyl)-dihydrofuran-2 (3H)-one (3BDO) that has been shown to protect VECs.

METHODS

First, we performed a proteomics analysis on the oxLDL-activated vascular VECs in the presence or absence of 3BDO. Next, we constructed the heterogeneous nuclear ribonucleoprotein E1 (hnRNP E1) mutants at Ser43 and used the RNA-ChIP technique to investigate the relationship between hnRNP E1 and PDI production. Furthermore, we examined the effect of 3BDO on oxLDL-altered phosphorylation of Akt1 and Akt2. Finally, we studied the effect of 3BDO on oxLDL-altered PDI protein level in apolipoprotein E(-/-) mice with advanced atherosclerosis.

RESULTS

In VECs, oxLDL-increased PDI protein level, induced hnRNP E1 phosphorylation at Ser43, suppressed the binding of hnRNP E1 to PDI 5'UTR and induced the phosphorylation of Akt2 but not Akt1. All of these processes were blocked by 3BDO. Importantly, Ser43 mutant of hnRNP E1 inhibited the increase of PDI protein level and the decrease of the binding of hnRNP E1 and PDI 5'UTR induced by oxLDL. Furthermore, 3BDO suppressed oxLDL-induced PDI protein increase in the serum and plaque endothelium of apolipoprotein E(-/-) mice.

CONCLUSION

hnRNP E1 is a new regulator of PDI translation in oxLDL-activated VECs, and 3BDO is a powerful agent for controlling PDI overproduction.

The prevalence of schizophrenia in mainland China: evidence from epidemiological surveys

OBJECTIVE

Schizophrenia is a severe mental disorder. Its prevalence appears inconsistent in different regions of China; thus, we conducted this meta-analysis to estimate the prevalence of schizophrenia in mainland China.

METHOD

Studies on the prevalence of schizophrenia in mainland China were identified from electronic databases up to July 2013. Meta-analysis was used for prevalence of schizophrenia estimate.

RESULTS

For lifetime prevalence of schizophrenia, prevalence of 5.44 per 1000 (overall), 5.33 per 1000 (males), 5.51 per 1000 (females), 6.60 per 1000 (urban) and 4.73 per 1000 (rural) were estimated; there was no significant difference between males and females, while prevalence for urban dwellers was higher than for rural (OR=1.44, 95%CI: 1.30-1.59). For point prevalence of schizophrenia, prevalence of 4.62 per 1000 (overall), 4.63 per 1000 (males), 4.95 per 1000 (females), 5.15 per 1000 (urban) and 4.44 per 1000 (rural) were estimated; no statistical difference was found in males and females, but prevalence for urban dwellers was higher than for rural (OR=1.20; 95%CI: 1.02-1.41).

CONCLUSION

The prevalence estimate results were consistent with the international prevalence estimate of schizophrenia in mainland China. There was no significant difference between males and females, while prevalence for urban dwellers was higher than for rural.

Losartan attenuates paraquat-induced pulmonary fibrosis in rats

Paraquat (PQ) is one of the most widely used herbicides in the world and can cause pulmonary fibrosis in the cases with intoxication. Losartan, an angiotensin II type 1 receptor antagonist, has beneficial effects on the treatment of fibrosis. The aim of this study was to examine the effect of losartan on pulmonary fibrosis in PQ-intoxicated rats. Adult male Sprague Dawley rats (n = 32, 180-220 g) were randomly assigned to four groups: (i) control group; (ii) PQ group; (iii) PQ + losartan 7d group; and (iv) PQ + losartan 14d group. Losartan treatment (intragastrically (i.g.), 10 mg/kg) was performed for 7 and 14 days after a single i.g. dose of 40 mg/kg PQ. All rats were killed on the 16th day, and hematoxylin-eosin and Masson's trichrome staining were used to examine lung injury and fibrosis. The levels of hydroxyproline and transforming growth factor β1 (TGF-β1), matrix metallopeptidase 9 (Mmp9), and tissue inhibitor of metalloproteinase 1 (TIMP-1) messenger RNA (mRNA) expression and relative expression levels of collagen type I and III were also detected. PQ caused a significant increase in hydroxyproline content, mRNA expression of TGF-β1, Mmp9, and TIMP-1, and relative expression levels of collagen type I and III ( p < 0.05), while losartan significantly decreased the amount of hydroxyproline and downregulated TGF-β1, Mmp9, and TIMP-1 mRNA and collagen type I and III expressions ( p < 0.05). Histological examination of PQ-treated rats showed lung injury and widespread inflammatory cell infiltration in the alveolar space and pulmonary fibrosis, while losartan could markedly reduce such damage and prevent pulmonary fibrosis. The results of this study indicated that losartan could reduce lung damage and prevent pulmonary fibrosis induced by PQ.

Protection from vascular endothelial dysfunction in acute glycemic load-induced primary hypertension by vitamin C and E

This study aimed to investigate the influence of acute glycemic load on vascular endothelial function in patients with hypertension and to evaluate the protective effect of vitamins C and E during the acute glycemic phase. We randomly selected 39 hypertensive patients and 21 normal subjects and divided them into 3 groups: 75 g oral glucose (glycemic load group), 75 g glucose+0.9 g vitamin C (VC group), 75 g glucose+2 g vitamin C+0.8 g vitamin E (VC+VE group). Extravascular color Doppler ultrasound was used to detect brachial artery flow-mediated vasodilation at 0, 1, 2, and 3 h, and, at the same time, serum anti-oxidant products were measured. Basic endothelial functions in patients with hypertension were decreased in the glycemic load group (9.48±3.33 versus 13.09±6.78%, P<0.05), and was even more depressed in the hypertensive group (9.48±3.33 versus 14.20±6.48%, P<0.05). Antioxidant vitamins played a dose-dependent protective role on acute damage of endothelial function due to glycemic load. Acute high blood sugar damaged vascular endothelial functions, especially in hypertensive patients, but this effect can be reversed by large doses of vitamin C and E.

Usp9x- and Noxa-mediated Mcl-1 downregulation contributes to pemetrexed-induced apoptosis in human non-small-cell lung cancer cells

Pemetrexed, a folate antimetabolite, combined with cisplatin is used as a first-line therapy for malignant pleural mesothelioma (MPM) and locally advanced or metastatic non-small-cell lung cancer (NSCLC). Pemetrexed arrests cell cycle by inhibiting three enzymes in purine and pyrimidine synthesis that are necessary for DNA synthesis. Pemetrexed also promotes apoptosis in target cells, but little is known about its mechanism in cancer cells. We have previously shown that pemetrexed can result in endoplasmic reticulum (ER) stress, and it can lead to downstream apoptosis. In this study, we further elucidate this mechanism. Our data show that pemetrexed increases Noxa expression through activating transcription factor 4 (ATF4) and activating transcription factor 3 (ATF3) upregulation. Furthermore, pemetrexed induces apoptosis by activating the Noxa-Usp9x-Mcl-1 pathway. Inhibition of Noxa by small interfering RNA (siRNA) promotes Usp9x (ubiquitin-specific peptidase 9, X-linked) expression. Moreover, downregulation of the deubiquitinase Usp9x by pemetrexed results in downstream reduction of myeloid cell leukemia 1 (Mcl-1) expression. Mechanistically, Noxa upregulation likely reduces the availability of Usp9x to Mcl-1, thereby promoting its ubiquitination and degradation, leading to the apoptosis of neoplastic cells. Thus, our findings demonstrate that Noxa-Usp9x-Mcl-1 axis may contribute to pemetrexed-induced apoptosis in human lung cancer cells.

HIV latency. Specific HIV integration sites are linked to clonal expansion and persistence of infected cells

The persistence of HIV-infected cells in individuals on suppressive combination antiretroviral therapy (cART) presents a major barrier for curing HIV infections. HIV integrates its DNA into many sites in the host genome; we identified 2410 integration sites in peripheral blood lymphocytes of five infected individuals on cART. About 40% of the integrations were in clonally expanded cells. Approximately 50% of the infected cells in one patient were from a single clone, and some clones persisted for many years. There were multiple independent integrations in several genes, including MKL2 and BACH2; many of these integrations were in clonally expanded cells. Our findings show that HIV integration sites can play a critical role in expansion and persistence of HIV-infected cells.

Heat stress induces apoptosis through transcription-independent p53-mediated mitochondrial pathways in human umbilical vein endothelial cell

Cells apoptosis induced by intense heat stress is the prominent feature of heat-related illness. However, little is known about the biological effects of heat stress on cells apoptosis. Herein, we presented evidence that intense heat stress could induce early apoptosis of HUVEC cells through activating mitochondrial pathway with changes in mitochondrial membrane potential(ΔΨm), release of cytochrome c, and activation of caspase-9 and -3. We further revealed that p53 played a crucial role in heat stress-induced early apoptosis, with p53 protein rapidly translocated into mitochondria. Using pifithrin-α(PFT), a p53's mitochondrial translocation inhibitor, we found that pretreated with PFT, heat stress induced mitochondrial p53 translocation was significantly suppressed, accompanied by a significant alleviation in the loss of ΔΨm, cytochrome c release and caspase-9 activation. Furthermore, we also found that generation of reactive oxygen species (ROS) was a critical mediator in heat stress-induced apoptosis. In addition, the antioxidant MnTMPyP significantly decreased the heat stress-induced p53's mitochondrial translocation, followed by the loss of ΔΨm, cytochrome c release, caspase-9 activation and heat stress-mediated apoptosis. Conclusively, these findings indicate the contribution of the transcription-independent mitochondrial p53 pathway to early apoptosis in HUVEC cells induced by oxidative stress in response to intense heat stress.

Regulatory interplay between NFIC and TGF-β1 in apical papilla-derived stem cells

While transforming growth factor-β1 (TGF-β1) can regulate odontoblast differentiation in tooth crown morphogenesis, its effects on cells including stem cells from the apical papilla (SCAPs) involved in root formation are unclear. Nuclear factor I-C (NFIC) has been implicated in the regulation of root development, and interplay with TGF-β1 signaling has been reported in some cell types. We hypothesize that NFIC and TGF-β1 are important to the behavior of SCAPs and that the interplay between these molecules controls the regulation of the odontogenic differentiation of SCAPs. TGF-β1 inhibited the proliferation of SCAPs and their mineralization. Real-time polymerase chain-reaction (RT-PCR) and Western blot results showed that TGF-β1 significantly decreased osteogenic/dentinogenic gene expression. The inhibition of TGF-β/Smad signaling (SIS3) attenuated the suppressive effect of TGF-β1 on SCAPs. Importantly, overexpression of NFIC antagonized the effects of TGF-β1 on SCAPs, while knockdown of NFIC enhanced these effects, demonstrating a key regulatory role for NFIC in modulating TGF-β1 signaling in SCAPs. We conclude that this interplay between NFIC and TGF-β1 regulates SCAPs behavior and can determine the differentiation of these cells. These signaling interactions help inform the development of regenerative strategies aimed at root growth and development in immature teeth for endodontic treatment.

A novel splicing site mutation of the GPR143 gene in a Chinese X-linked ocular albinism pedigree

Ocular albinism is an X-linked inherited disease characterized by hypopigmentation of the iris and nystagmus. To identify a new disease-causing mutation of ocular albinism, we collected a Han Chinese pedigree with 7 male congenital nystagmus patients over 3 generations. Slit-lamp photography and optical coherence tomography were performed for the proband. Genomic DNA was extracted from a whole blood sample from the proband using the high-salt method. Polymerase chain reaction (PCR) sequencing was carried out for GPR143 and FRMD7 genes. The three-dimensional structures of the wild-type and mutant GPR143 proteins were determined using SWISS-MODEL. The transmission of the disease in the pedigree clearly followed an X-linked pattern. The proband had significant iris and fundus hypopigmentation. Optical coherence tomography showed severe foveal hypoplasias in both eyes of the proband. A novel splicing site (G/C) mutation was found on the boundary of the 6th intron and the 7th exon of the GPR143 gene, resulting in a 9-amino-acid deletion (codons 257-265) in the 6th transmembrane domain of the GPR143 protein. In conclusion, a novel splicing site mutation of the GPR143 gene was found in a Han Chinese congenital ocular albinism pedigree.

Cotton dust, endotoxin and cancer mortality among the Shanghai textile workers cohort: a 30-year analysis

BACKGROUND

Although occupational exposure to cotton dust and endotoxin is associated with adverse respiratory health, associations with cancer are unclear. We investigated cancer mortality in relation to cotton dust and endotoxin exposure in the Shanghai textile workers cohort.

METHODS

We followed 444 cotton textile and a reference group of 467 unexposed silk workers for 30 years (26 777 person-years). HRs for all cancers combined (with and without lung cancer) and gastrointestinal cancer were estimated in Cox regression models as functions of cotton textile work and categories of cumulative exposure (low, medium, high), after adjustment for covariates including pack-years smoked. Different lag years accounted for disease latency.

RESULTS

Risks of mortality from gastrointestinal cancers and all cancers combined, with the exclusion of lung cancer, were increased in cotton workers relative to silk workers. When stratified by category of cumulative cotton exposure, in general, risks were greatest for 20-year lagged medium exposure (all cancers HR=2.7 (95% CI 1.4 to 5.2); cancer excluding lung cancer HR=3.4 (1.7-7.0); gastrointestinal cancer HR=4.1 (1.8-9.7)). With the exclusion of lung cancer, risks of cancer were more pronounced. When stratified by category of cumulative endotoxin exposure, consistent associations were not observed for all cancers combined. However, excluding lung cancer, medium endotoxin exposure was associated with all cancers and gastrointestinal cancer in almost all lag models.

CONCLUSIONS

Cotton dust may be associated with cancer mortality, especially gastrointestinal cancer, and endotoxin may play a causative role. Findings also indirectly support a protective effect of endotoxin on lung cancer.

Effects of propofol on damage of rat intestinal epithelial cells induced by heat stress and lipopolysaccharides

Gut-derived endotoxin and pathogenic bacteria have been proposed as important causative factors of morbidity and death during heat stroke. However, it is still unclear what kind of damage is induced by heat stress. In this study, the rat intestinal epithelial cell line (IEC-6) was treated with heat stress or a combination of heat stress and lipopolysaccharide (LPS). In addition, propofol, which plays an important role in anti-inflammation and organ protection, was applied to study its effects on cellular viability and apoptosis. Heat stress, LPS, or heat stress combined with LPS stimulation can all cause intestinal epithelial cell damage, including early apoptosis and subsequent necrosis. However, propofol can alleviate injuries caused by heat stress, LPS, or the combination of heat stress and LPS. Interestingly, propofol can only mitigate LPS-induced intestinal epithelial cell apoptosis, and has no protective role in heat-stress-induced apoptosis. This study developed a model that can mimic the intestinal heat stress environment. It demonstrates the effects on intestinal epithelial cell damage, and indicated that propofol could be used as a therapeutic drug for the treatment of heat-stress-induced intestinal injuries.

Novel EDA p.Ile260Ser mutation linked to non-syndromic hypodontia

Hypodontia, a tooth developmental disease, can affect chewing and pronunciation. Mutations in the ectodysplasin-A (EDA) gene can lead to both X-linked hypohidrotic ectodermal dysplasia (XLHED) and non-syndromic hypodontia (NSH). However, the mechanism by which these 2 related but different disorders are caused by the distinct mutations in EDA is unknown. In this study, we identified a novel missense mutation (c.779 T>G) in a Chinese family with NSH via a direct sequencing approach. This mutation results in an Ile260Ser substitution in the tumor necrosis factor (TNF) homology domain. Homology modeling suggests that this alteration may induce a conformational change in the hydrophobic center of the TNF homology domain. Furthermore, by exploring systematic 3D conformation analysis and calculation of residue relative solvent accessibility (RSA) for all the reported mutated amino acid sites on EDA's TNF homology domain, we found that the site mutations at the interior may be linked to XLHED, while those at the surface are more likely to be associated with NSH. These findings may aid in the discovery of unidentified functionally significant mutation sites in the EDA gene and provide a new way to clarify the mechanisms by which the XLHED and NSH phenotypes arise from mutations in the same gene.