Chondrostereum sp., a marine fungus isolated from a soft coral Sarcophyton tortuosum, can yield hirsutane framework sesquiterpenoids. However, the metabolites profiles vary dramatically with the composition change of the culture media. This fungus was cultured in a liquid medium containing glycerol as the carbon source, and two new metabolites, chondrosterins I and J (1 and 2), were obtained. Their structures were elucidated primarily based on MS, NMR and X-ray single-crystal diffraction data. By comparison with the known hirsutane sesquiterpenoids, chondrosterins I and J have unique structural features, including a methyl was migrated from C-2 to C-6, and the methyl at C-3 was carboxylated. Compound 2 exhibited potent cytotoxic activities against the cancer cell lines CNE-1 and CNE-2 with the IC50 values of 1.32 and 0.56 μM.
marine fungus; Chondrostereum sp.; sesquiterpenoids; chondrosterins; cytotoxic activity
Vγ9Vδ2 (also termed Vγ2Vδ2) T cells, a major human peripheral blood γδ T cell subset, recognize microbial (E)-4-hydroxy-3-methylbut-2-enyl diphosphate and endogenous isopentenyl diphosphate in a TCR-dependent manner. The recognition does not require specific accessory cells, antigen uptake, antigen processing, or MHC class I, class II, or class Ib expression. This subset of T cells plays important roles in mediating innate immunity against a wide variety of infections and displays potent and broad cytotoxic activity against human tumor cells. Because γδT cells express both natural killer receptors such as NKG2D and γδ T cell receptors, they are considered to represent a link between innate and adaptive immunity. In addition, activated γδ T cells express a high level of antigen-presenting cell-related molecules and can present peptide antigens derived from destructed cells to αβ T cells. Utilizing these antimicrobial and anti-tumor properties of γδ T cells, preclinical and clinical trials have been conducted to develop novel immunotherapies for infections and malignancies. Here, we review the immunological properties of γδ T cells including the underlying recognition mechanism of nonpeptitde antigens and summarize the results of γδ T cell-based therapies so far performed. Based on the results of the reported trials, γδ T cells appear to be a promising tool for novel immunotherapies against certain types of diseases.
γδ T cells; nonpeptide antigen; tumor; infection; autoimmune and allergic diseases; immunotherapy
Influenza has always been one of the major threats to human health. The Spanish influenza in 1918, the pandemic influenza A/H1N1 in 2009, and the avian influenza A/H5N1 have brought about great disasters or losses to mankind. More recently, a novel avian influenza A/H7N9 broke out in China and until December 2, 2013, it had caused 139 cases of infection, including 45 deaths. Its risk and pandemic potential attract worldwide attention. In this article, we summarize epidemiology, virology characteristics, clinical symptoms, diagnosis methods, clinical treatment and preventive measures about the avian influenza A/H7N9 virus infection to provide a reference for a possible next wave of flu outbreak.
H7N9 virus; avian influenza A; infection; diagnosis; treatment; prevention.
Several studies have brought about increasing evidence to support the hypothesis that miRNAs play a pivotal role in multiple processes of carcinogenesis, including cell growth, apoptosis, differentiation, and metastasis. In this study, we investigated the potential role of miR-31 in colorectal cancer (CRC) aggressiveness and its underlying mechanisms. We found that miR-31 increased in CRC cells originated from metastatic foci and human primary CRC tissues with lymph node metastases. Furthermore, the high-level expression of miR-31 was significantly associated with a more aggressive and poor prognostic phenotype of patients with CRC (p < 0.05). The stable over-expression of miR-31 in CRC cells was sufficient to promote cell proliferation, invasion, and migration in vitro. It facilitated tumor growth and metastasis in vivo too. Further studies showed that miR-31 can directly bind to the 3’untranslated region (3’UTR) of SATB2 mRNA and subsequently repress both the mRNA and protein expressions of SATB2. Ectopic expression of SATB2 by transiently transfected with pCAG-SATB2 vector encoding the entire SATB2 coding sequence could reverse the effects of miR-31 on CRC tumorigenesis and progression. In addition, ectopic over-expression of miR-31 in CRC cells induced epithelial-mesenchymal transition (EMT). Our results illustrated that the up-regulation of miR-31 played an important role in CRC cell proliferation, invasion, and metastasis in vitro and in vivo through direct repressing SATB2, suggesting a potential application of miR-31 in prognosis prediction and therapeutic application in CRC.
Green cloud data center has become a research hotspot of virtualized cloud computing architecture. Since live virtual machine (VM) migration technology is widely used and studied in cloud computing, we have focused on the VM placement selection of live migration for power saving. We present a novel heuristic approach which is called PS-ABC. Its algorithm includes two parts. One is that it combines the artificial bee colony (ABC) idea with the uniform random initialization idea, the binary search idea, and Boltzmann selection policy to achieve an improved ABC-based approach with better global exploration's ability and local exploitation's ability. The other one is that it uses the Bayes theorem to further optimize the improved ABC-based process to faster get the final optimal solution. As a result, the whole approach achieves a longer-term efficient optimization for power saving. The experimental results demonstrate that PS-ABC evidently reduces the total incremental power consumption and better protects the performance of VM running and migrating compared with the existing research. It makes the result of live VM migration more high-effective and meaningful.
Green cloud data center has become a research hotspot of virtualized cloud computing architecture. And load balancing has also been one of the most important goals in cloud data centers. Since live virtual machine (VM) migration technology is widely used and studied in cloud computing, we have focused on location selection (migration policy) of live VM migration for power saving and load balancing. We propose a novel approach MOGA-LS, which is a heuristic and self-adaptive multiobjective optimization algorithm based on the improved genetic algorithm (GA). This paper has presented the specific design and implementation of MOGA-LS such as the design of the genetic operators, fitness values, and elitism. We have introduced the Pareto dominance theory and the simulated annealing (SA) idea into MOGA-LS and have presented the specific process to get the final solution, and thus, the whole approach achieves a long-term efficient optimization for power saving and load balancing. The experimental results demonstrate that MOGA-LS evidently reduces the total incremental power consumption and better protects the performance of VM migration and achieves the balancing of system load compared with the existing research. It makes the result of live VM migration more high-effective and meaningful.
T lymphoma invasion and metastasis 1 (Tiam1) is a potential modifier of tumor development and progression. Our previous study in vitro and in nude mice suggested a promotion role of Tiam1 on invasion and metastasis of colorectal cancer (CRC). In the present study, we generated Tiam1/C1199-CopGFP transgenic mice to investigate the tumorigenetic, invasive and metastatic alterations in the colon and rectum of wild-type and Tiam1 transgenic mice under 1,2-dimethylhydrazine (DMH) treatment.
Transgenic mice were produced by the method of pronuclear microinlectlon. Whole-body fluorescence imaging (Lighttools, Edmonton, Alberta, Canada), PCR, and immunohistochemical techniques (IHC) were applied sequentially to identify the transgenic mice. The carcinogen DMH (20 mg/kg) was used to induce colorectal tumors though intraperitoneal (i.p.) injections once a week for 24 weeks from the age of 4 weeks on Tiam1 transgenic or non-transgenic mice.
We successfully generated Tiam1/C1199-CopGFP transgenic mice and induced primary tumors in the intestine of both wild type and Tiam1 transgenic mice by DMH treatment. In addition, Tiam1 transgenic mice developed larger and more aggressive neoplasm than wild-type mice. Moreover, immunohistochemical staining revealed that upregulation of Tiam1 was correlated with increased expression of β-Catenin and Vimentin, and downregulation of E-Cadherin in these mice.
Our study has provided in vivo evidence supporting that Tiam1 promotes invasion and metastasis of CRC, most probably through activation of Wnt/β-catenin signaling pathway, in a Tiam1 transgenic mouse model.
Src-associated in mitosis (Sam68; 68 kDa) has been implicated in the oncogenesis and progression of several human cancers. The aim of this study was to investigate the clinicopathologic significance of Sam68 expression and its subcellular localization in colorectal cancer (CRC).
Sam68 expression was examined in CRC cell lines, nine matched CRC tissues and adjacent noncancerous tissues using reverse transcription (RT)-PCR, quantitative RT-PCR and Western blotting. Sam68 protein expression and localization were determined in 224 paraffin-embedded archived CRC samples using immunohistochemistry. Statistical analyses were applied to evaluate the clinicopathologic significance.
Sam68 was upregulated in CRC cell lines and CRC, as compared with normal tissues; high Sam68 expression was detected in 120/224 (53.6%) of the CRC tissues. High Sam68 expression correlated significantly with poor differentiation (P = 0.033), advanced T stage (P < 0.001), N stage (P = 0.023) and distant metastasis (P = 0.033). Sam68 nuclear localization correlated significantly with poor differentiation (P = 0.002) and T stage (P =0.021). Patients with high Sam68 expression or Sam68 nuclear localization had poorer overall survival than patients with low Sam68 expression or Sam68 cytoplasmic localization. Patients with high Sam68 expression had a higher risk of recurrence than those with low Sam68 expression.
Overexpression of Sam68 correlated highly with cancer progression and poor differentiation in CRC. High Sam68 expression and Sam68 nuclear localization were associated with poorer overall survival.
Sam68; Biomarker; Prognosis; Colorectal cancer
20-HETE promotes endothelial dysfunction by uncoupling eNOS, stimulating O2− production and reducing NO bioavailability. Moreover, 20-HETE-dependent vascular dysfunction and hypertension are associated with upregulation of the renin-angiotensin system (RAS). This study was undertaken to examine the contribution of RAS to 20-HETE actions in the vascular endothelium.
Methods and Results
In endothelial cells, 20-HETE induced ACE mRNA levels and increased ACE protein and activity by 2-3-fold; these effects were negated with addition of the 20-HETE antagonist, 20-HEDE. 20-HETE-induced ACE expression was PKC-independent and EGFR-tyrosine kinase- and IKKβ-dependent. ACE siRNA abolished 20-HETE-mediated inhibition of NO production and stimulation of O2− generation whereas AT1R siRNA attenuated these effects by 40%. 20-HETE-stimulated O2− production was negated by 20-HEDE and was attenuated by lisinopril and losartan. Importantly, 20-HETE-mediated impairment of acetylcholine-induced relaxation in rat renal interlobar arteries was also attenuated by lisinopril and losartan.
These results indicate that ACE and Ang II-AT1R activation contribute to 20-HETE-mediated endothelial cell and vascular dysfunction and further enforce the notion that excessive production of 20-HETE within the vasculature leads to hypertension via mechanisms that include the induction of endothelial ACE, thus perpetuating an increase in vascular Ang II which, together with 20-HETE, promotes vascular dysfunction.
The broad spectrum kinase inhibitor sunitinib is a first-line therapy for advanced clear cell renal cell carcinoma (ccRCC), a deadly form of kidney cancer. Unfortunately, most patients develop sunitinib resistance and progressive disease after about 1 year of treatment. In this study, we evaluated the mechanisms of resistance to sunitinib to identify the potential tactics to overcome it. Xenograft models were generated that mimicked clinical resistance to sunitinib. Higher microvessel density was found in sunitinib-resistant tumors, indicating that an escape from antiangiogenesis occurred. Notably, escape coincided with increased secretion of interleukin-8 (IL-8) from tumors into the plasma, and coadministration of an IL-8 neutralizing antibody resensitized tumors to sunitinib treatment. In patients who were refractory to sunitinib treatment, IL-8 expression was elevated in ccRCC tumors, supporting the concept that IL-8 levels might predict clinical response to sunitinib. Our results reveal IL-8 as an important contributor to sunitinib resistance in ccRCC and a candidate therapeutic target to reverse acquired or intrinsic resistance to sunitinib in this malignancy.
Although protein kinase C-θ (PKC-θ)-deficient mice are resistant to the induction of Th17-dependent experimental autoimmune encephalomyelitis, the function of PKC-θ in Th17 differentiation remains unknown. Here we show that purified, naive CD4 PKC-θ−/− T cells were defective in Th17 differentiation, whereas Th1 and Th2 differentiation appeared normal. Activation of PKC-θ with PMA promoted Th17 differentiation in wild type (WT) but not PKC-θ−/− T cells. Furthermore, PKC-θ−/− T cells had notably lower levels of Stat3, a transcription factor required for Th17 differentiation, and PMA markedly stimulated the expression of Stat3 in WT but not PKC-θ−/− T cells. In contrast, activation of Stat4 and Stat6, which are critical for Th1 and Th2 differentiation, was normal in PKC-θ−/− T cells. Forced expression of Stat3 significantly increased Th17 differentiation in PKC-θ−/− T cells, suggesting that reduced Stat3 levels were responsible for impaired Th17 differentiation and that Stat3 lies downstream of PKC-θ. Constitutively active PKC-θ or WT PKC-θ activated by either PMA or TCR cross-linking, stimulated expression of a luciferase reporter gene driven by the Stat3 promoter. PKC-θ-mediated activation of the Stat3 promoter was inhibited by dominant negative AP-1 and IκB kinase-β, but stimulated by WT AP-1 and IκB kinase-β, suggesting that PKC-θ stimulates Stat3 transcription via the AP-1 and NF-κB pathways. Lastly, conditions favoring Th17 differentiation induced the highest activation level of PKC-θ. Altogether the data indicate that PKC-θ integrates the signals from TCR signaling and Th17 priming cytokines to up-regulate Stat3 via NF-κB and AP-1, resulting in the stimulation of Th17 differentiation.
It is well known that ErbB2, a receptor tyrosine kinase, localizes on the plasma membrane. Here we describe a novel observation that ErbB2 also localizes in mitochondria of cancer cells and patient samples. We found that ErbB2 translocates into mitochondria through the association with mtHSP70. Additionally, mitochondrial ErbB2 (mtErbB2) negatively regulates mitochondrial respiratory functions. Oxygen consumption and activities of complexes of the mitochondrial electron transport chain were decreased in mtErbB2-overexpressing cells. Mitochondrial membrane potential and the cellular ATP level also were decreased. In contrast, mtErbB2 enhanced cellular glycolysis. The translocation of ErbB2 and its impact on mitochondrial function are kinase dependent. Interestingly, cancer cells with higher levels of mtErbB2 were more resistant to ErbB2 targeting antibody trastuzumab. Our study provides a novel perspective on the metabolic regulatory function of ErbB2 and reveals that mtErbB2 plays an important role in the regulation of cellular metabolism and cancer cell resistance to therapeutics.
Protein Kinase C-θ (PKC-θ) has been shown to be a critical T cell receptor (TCR) signaling molecule that promotes the activation and differentiation of naïve T cells into inflammatory effector T cells. We demonstrate here that PKC-θ-mediated signals inhibit iTreg differentiation via an AKT-Forkhead Box O1/3a (FoxO1/3A) pathway. Transforming growth factor β-induced iTreg differentiation was enhanced in PKC-θ−/− T cells or WT cells treated with a specific PKC-θ inhibitor, but was inhibited by the PKC-θ activator PMA, or by CD28 crosslinking which enhances PKC-θ activation. PKC-θ−/− T cells had reduced activity of the AKT kinase, and the expression of a constitutively active form of AKT in PKC-θ−/− T cells restored ability to inhibit iTreg differentiation. Furthermore, knockdown or over expression of the AKT downstream targets FoxO1 and FoxO3a was found to inhibit or promote iTreg differentiation in PKC-θ−/− T cells accordingly, indicating that the AKT-FoxO1/3A pathway is responsible for the inhibition of iTreg differentiation of iTreg downstream of PKC-θ. We conclude that PKC-θ is able to control T cell-mediated immune responses by shifting the balance between the differentiation of effector T cells and inhibitory Tregs.
Regulatory T cell (Treg)-mediated immunosuppression represents one of the crucial tumor immune evasion mechanisms and is a main obstacle for successful tumor immunotherapy. Hypoxia, a common feature of solid tumors, has been associated with potentiated immunosuppression, decreased therapeutic response, malignant progression and local invasion. Unfortunately, the link between hypoxia and Treg-mediated immune tolerance in gastric cancer remains poorly understood. In our study, Tregs and hypoxia inducible factor-1α were found to be positively correlated with each other and were increased with the tumor progression. A subsequent in vitro study indicated that supernatants derived from gastric cancer cells under hypoxic condition, could induce the expression of Foxp3 via TGF-β1. These findings confirmed the crucial role of Tregs as a therapeutic target in gastric cancer therapy and provided helpful thoughts for the design of immunotherapy for gastric cancer in the future.
In progressive kidney diseases, fibrosis represents the common pathway to end-stage kidney failure. Transforming growth factor-β1 (TGF-β1) is a pleiotropic cytokine that has been established as a central mediator of kidney fibrosis. Emerging evidence demonstrates a complex scheme of signaling networks that enable multifunctionality of TGF-β1 actions. Specific targeting of TGF-β signaling pathway is seemingly critical and attractive molecular therapeutic strategy. TGF-β1 signals through the interaction of type I (TβRI) and type II (TβRII) receptors to activate distinct intracellular pathways involving the Smad and the non-Smad. The Smad signaling axis is known as the canonical pathway induced by TGF-β1. Importantly, recent investigations show that TGF-β1 also induces various non-Smad signaling pathways. In this review, we focus on current insights into the mechanism and function of Smad-independent signaling pathway via TGF-β-activated kinase 1 (TAK1) and its role in mediating the profibrotic effects of TGF-β1.
Transforming growth factor-β1; intracellular signaling; TGF-β-activated kinase 1; fibrosis; chronic kidney disease
Since the initial report of targeted-enrichment (Albert et al, 2007) we have been evolving the design and utility of capture reagents and methods, while taking advantage of the parallel advances in sequencing platforms. New exome designs target a comprehensive set of coding exons from 6 different gene databases, as well as computationally predicted coding and non-coding elements: regulatory regions, and conserved UTRs. Library automation, reduction of DNA input samples, capture hybridization multiplexing and application of faster read mapping tools such as BWA, together allow a rate of >4,300 libraries/captures per month, with >40,000 exome and regional capture libraries completed to date. In addition, a fully integrated informatics and analysis pipeline (Mercury), supports all aspects of data flow and analysis from the initial data production on the sequencing instrument to annotated variant calls (SNPs and small Indels). These laboratory methods and analysis pipelines have been production hardened at the Human Genome Sequencing Center (HGSC) and have now been applied toward clinical exome sequencing. Through a joint collaboration between the Human Genome Sequencing Center and the Medical Genetics Laboratories (MGL) of the Department of Molecular and Human Genetics, clinical exome sequencing and interpretation are now provided through the CAP/CLIA certified Whole Genome Laboratory (WGL). To date, the WGL has completed exome sequencing of 650 patient samples and final interpretation completed for over 450 patients with causative deleterious mutations identified in 25% of cases. Performance has been maintained to a high standard of 95% of the exome target bases represented at 20X coverage. Overall exome performance metrics, LIMS support, variant analysis and validation of the clinical pipeline for a CAP/CLIA environment will be presented.
TLR2 specifically recognizes a wide range of ligands by homodimerizing or heterodimerizing with TLR1 or TLR6. However, the molecular basis of the specific signalling transduction induced by TLR2 homodimerization or heterodimerization with TLR1 or TLR6 is largely unknown. In this study, we found three amino acid residues, two (663L and 688N) outside and one (681P) inside the BB loop, which were conserved in all of the TLRs, except for the TLR3 toll/IL-1R(TIR) domain. The responsiveness of human TLR2/2, TLR2/1 or TLR2/6 was completely lost when 663L and 688N were replaced with the corresponding amino acid residues in the TLR3 TIR domain, respectively. However, the response of TLR2 (P681A) to the high concentration of TLR2/TLR6 agonist was almost intact, but the activity of TLR2 (P681A) was greatly reduced when stimulated with the TLR2/1 agonist or the TLR2/2 agonist. Although the surface expression of TLR2 (L663E) was sharply reduced, both the intracellular distribution and the surface expression of all of the other TLR2 mutants were unchanged. The ability of all three TLR2 mutants to recruit MyD88, was consistent with their responsivenesses. Computer modelling indicated that the surface negative charge of all of the TLR2 mutants' BB loops was reduced. Thus, our data demonstrated that the 663L and 688N residues outside of the BB loop were essential for the responsiveness of TLR2/2, TLR2/1 and TLR2/6, but the 681P residue inside of the BB loop exhibited divergent roles in TLR2/2, TLR2/1 and TLR2/6 signalling transduction, thereby providing clues regarding the specific signalling transduction of TLR2/2, TLR2/1 and TLR2/6.
The aim of this study was to investigate human papillomavirus (HPV) infection and HPV genotype distributions in Urumqi, Xinjiang, China. The related risk factors for high-risk HPV infection was also analyzed. A stratified cluster sampling method was used for the population-based cervical cancer screening of women aged 18–69 years in the Urumqi Saybagh district. Exfoliated cervical cell samples were collected for liquid-based cytology detection and HPV genotyping DNA microarrays. Education level, number of sexual partners, condom use and occupation were used in the multivariate analysis model. The HPV infection rate of women working in service industries was significantly higher compared with those of white-collar workers, community residents and migrant workers. The 35–44-year-old migrant worker group had the highest HPV infection rates among all of the groups in the three different age ranges. The number of marriages, education level, smoking history, number of abortions, use of condoms, number of sexual partners, number of sexual partners in the past five years and occupation were all associated with female HPV infection rate (P<0.05). The 35–44-year-old women were the age group with the highest HPV infection rate. The HPV infection rate of females in service industries was the highest. Education level and condom use were protective factors of HPV infection, while the number of sexual partners and occupation were risk factors for HPV infection.
human papillomavirus; genotype distribution; cervical cancer
AIM: To compare synchronous laparoscopic cholecystectomy (LC) combined with endoscopic sphincterotomy (EST) and sequential LC combined with EST for treating cholecystocholedocholithiasis.
METHODS: A total of 150 patients were included and retrospectively studied. Among these, 70 were selected for the synchronous operation, in which the scheme was endoscopic retrograde cholangiopancreatography combined with EST during LC. The other 80 patients were selected for the sequential operation, in which the scheme involved first cutting the papillary muscle under endoscopy and then performing LC. The indexes in the two groups, including the operation time, the success rate, the incidence of complications, and the length of the hospital stay, were observed.
RESULTS: There were no significant differences between the groups in terms of the numbers of patients, sex distribution, age, American Society of Anesthesiologists score, serum bilirubin, γ-glutamyl transpeptidase, mean diameter of common bile duct stones, and previous medical and surgical history (P = 0.54, P = 0.18, P = 0.52, P = 0.22, P = 0.32, P = 0.42, P = 0.68, P = 0.70, P = 0.47 and P = 0.57). There was no significant difference in the surgical operation time between the two groups (112.1 ± 30.8 min vs 104.9 ± 18.2 min). Compared with the sequential operation group, the incidence of pancreatitis was lower (1.4% vs 6.3%), the incidence of hyperamylasemia (1.4% vs 10.0%, P < 0.05) was significantly reduced, and the length of the hospital stay was significantly shortened in the synchronous operation group (3 d vs 4.5 d, P < 0.001).
CONCLUSION: For treatment of cholecystocholedocholithiasis, synchronous LC combined with EST reduces incidence of complications, decreases length of hospital stay, simplifies the surgical procedure, and reduces operation time.
Laparoscopic cholecystectomy; Endoscopic sphincterotomy; Endoscopic retrograde cholangiopancreatography; Cholecystolithiasis; Choledocholithiasis
In continuation of our research to find biological components from Panax stipuleanatus, four oleanane-type triterpenes (12 to 15) were isolated successively. Fifteen oleanane-type saponins (1 to 15) were evaluated for nuclear factor (NF)-κB activity using a luciferase reporter gene assay in HepG2 cells. Compounds 6 to 11 inhibited NF-κB, with IC50 values between 3.1 to 18.9 μM. The effects on inducible nitric oxide synthase and cyclooxygenase-2 by compounds 8, 10, and 11 were also examined using reverse transcription-polymerase chain reaction. Three compounds (8, 10, and 11) inhibited NF-κB activity by reducing the concentration of inflammatory factors in HepG2 cells.
Panax ginseng; Panax stipuleanatus; Oleanane-type triterpenoid; Nuclear factor-κB
Type 1 diabetes mellitus (T1DM) is a chronic autoimmune disease resulting in the designated immune destruction of insulin producing β-cells, usually diagnosed in youth, and associated with important psychological, familial, and social disorders. Once diagnosed, patients need lifelong insulin treatment and will experience multiple disease-associated complications. There is no cure for T1DM currently. The last decade has witnessed great progress in elucidating the causes and treatment of the disease based on numerous researches both in rodent models of spontaneous diabetes and in humans. This article summarises our current understanding of the pathogenesis of T1DM, the roles of the immune system, genes, environment and other factors in the continuing and rapid increase in T1DM incidence at younger ages in humans. In addition, we discuss the strategies for primary and secondary prevention trials of T1DM. The purpose of this review is to provide an overview of this disorder's pathogenesis, risk factors that cause the disease, as well as to bring forward an ideal approach to prevent and cure the disorder.
Type 1 diabetes; pathogenesis; susceptibility gene; epigenetics; environmental factors; c-kit; PD-1; prevention trials.
Survival of CD4+CD8+ double positive (DP) thymocytes plays a critical role in shaping the peripheral T cell repertoire. However, the mechanisms responsible for the regulation of DP thymocyte lifespan remain poorly understood. In this work, we demonstrate that TCF-1 regulates DP thymocyte survival by up-regulating RORγt. Microarray analysis revealed that RORγt was significantly down-regulated in TCF-1−/− thymocytes that underwent accelerated apoptosis, whereas RORγt was greatly up-regulated in thymocytes that had enhanced survival due to transgenic expression of a stabilized β-catenin (β-catTg), a TCF-1 activator. Both TCF-1−/− and RORγt−/− DP thymocytes underwent similar accelerated apoptosis. Forced expression of RORγt successfully rescued TCF-1−/− DP thymocytes from apoptosis, whereas ectopically expressed TCF-1 was not able to rescue the defective T cell development due to lack of RORγt-supported survival. Furthermore, activation of TCF-1 by stabilized β-catenin was able to enhance DP thymocyte survival only in the presence of RORγt, indicating that RORγt acts downstream of TCF-1 in the regulation of DP thymocyte survival. Moreover, β-catenin/TCF-1 directly interacted with the RORγt promoter region and stimulated its activity. Therefore, our data demonstrate that TCF-1 enhances DP thymocyte survival through transcriptional up-regulation of RORγt, which we have previously shown to be an essential survival molecule for DP thymocytes.
Aim: A growing body of evidence has shown that increased formation of oxidized molecules and reactive oxygen species within the vasculature (i.e., the extracellular space) plays a crucial role in the initiation and progression of atherosclerosis and in the formation of unstable plaques. Peroxiredoxin 4 (PRDX4) is the only known secretory member of the antioxidant PRDX family. However, the relationship between PRDX4 and susceptibility to atherosclerosis has remained unclear. Results: To define the role of PRDX4 in hyperlipidemia-induced atherosclerosis, we generated hPRDX4 transgenic (Tg) and apolipoprotein E (apoE) knockout mice (hPRDX4+/+/apoE−/−). After feeding the mice a high-cholesterol diet, they showed fewer atheromatous plaques, less T-lymphocyte infiltration, lower levels of oxidative stress markers, less necrosis, a larger number of smooth muscle cells, and a larger amount of collagen, resulting in thickened fibrous cap formation and possible stable plaque phenotype as compared with apoE−/− mice. We also detected greater suppression of apoptosis and decreased Bax expression in hPRDX4+/+/apoE−/− mice than in apoE−/− mice. Bone marrow transplantation from hPRDX4+/+ donors to apoE−/− mice confirmed the antiatherogenic aspects of PRDX4, revealing significantly suppressed atherosclerotic progression. Innovation: In this study, we demonstrated for the first time that PRDX4 suppressed the development of atherosclerosis in apoE−/− mice fed a high-cholesterol diet. Conclusion: These data indicate that PRDX4 is an antiatherogenic factor and, by suppressing oxidative damage and apoptosis, that it may protect against the formation of vulnerable (unstable) plaques. Antioxid. Redox Signal. 17, 1362–1375.
Cranial radiation therapy can induce cognitive decline. Impairments of hippocampal neurogenesis are thought to be a paramountly important mechanism underlying radiation-induced cognitive dysfunction. In the mature nervous system, DNA double-strand breaks (DSBs) are mainly repaired by non-homologous end-joining (NHEJ) pathways. It has been demonstrated that NHEJ deficiencies are associated with impaired neurogenesis. In our study, rats were randomly divided into five groups to be irradiated by single doses of 0 (control), 0 (anesthesia control), 2, 10, and 20 Gy, respectively. The cognitive function of the irradiated rats was measured by open field, Morris water maze and passive avoidance tests. Real-time PCR was also used to detect the expression level of DNA DSB repair-related genes involved in the NHEJ pathway, such as XRCC4, XRCC5and XRCC6, in the hippocampus. The influence of different radiation doses on cognitive function in rats was investigated. From the results of the behavior tests, we found that rats receiving 20 Gy irradiation revealed poorer learning and memory, while no significant loss of learning and memory existed in rats receiving irradiation from 0–10 Gy. The real-time PCR and Western blot results showed no significant difference in the expression level of DNA repair-related genes between the 10 and 20 Gy groups, which may help to explain the behavioral results, i.e. DNA damage caused by 0–10 Gy exposure was appropriately repaired, however, damage induced by 20 Gy exceeded the body's maximum DSB repair ability. Ionizing radiation-induced cognitive impairments depend on the radiation dose, and more directly on the body's own ability to repair DNA DSBs via the NHEJ pathway.
DNA repair; DSB; radiation; XRCC4; XRCC5; XRCC6; cognitive impairments
N-linked glycosylation of protein is a posttranslational modification found in all three domains of life. The flagellin proteins of the archaeon Methanococcus maripaludis are known to be modified with an N-linked tetrasaccharide consisting of N-acetylgalactosamine (GalNAc), a diacetylated glucuronic acid (GlcNAc3NAc), an acetylated and acetamidino-modified mannuronic acid with a substituted threonine group (ManNAc3NAmA6Thr), and a novel terminal sugar residue [(5S)-2-acetamido-2,4-dideoxy-5-O-methyl-α-l-erythro-hexos-5-ulo-1,5-pyranose]. To identify genes involved in biosynthesis of the component sugars of this glycan, three genes, mmp1081, mmp1082, and mmp1083, were targeted for in-frame deletion, based on their annotation and proximity to glycosyltransferase genes known to be involved in assembly of the glycan. Mutants carrying a deletion in any of these three genes remained flagellated and motile. A strain with a deletion of mmp1081 had lower-molecular-mass flagellins in Western blots. Mass spectrometry of purified flagella revealed a truncated glycan with the terminal sugar absent and the threonine residue and the acetamidino group missing from the third sugar. No glycan modification was seen in either the Δmmp1082 or Δmmp1083 mutant grown in complex Balch III medium. However, a glycan identical to the Δmmp1081 glycan was observed when the Δmmp1082 or Δmmp1083 mutant was grown under ammonia-limited conditions. We hypothesize that MMP1082 generates ammonia and tunnels it through MMP1083 to MMP1081, which acts as the amidotransferase, modifying the third sugar residue of the M. maripaludis glycan with the acetamidino group.