Fanconi anemia (FA) signaling, a key genomic maintenance pathway, is activated in response to replication stress. Here, we report that phosphorylation of the pivotal pathway protein FANCD2 by CHK1 ...triggers its FBXL12-dependent proteasomal degradation, facilitating FANCD2 clearance at stalled replication forks. This promotes efficient DNA replication under conditions of CYCLIN E- and drug-induced replication stress. Reconstituting FANCD2-deficient fibroblasts with phosphodegron mutants failed to re-establish fork progression. In the absence of FBXL12, FANCD2 becomes trapped on chromatin, leading to replication stress and excessive DNA damage. In human cancers, FBXL12, CYCLIN E, and FA signaling are positively correlated, and FBXL12 upregulation is linked to reduced survival in patients with high CYCLIN E-expressing breast tumors. Finally, depletion of FBXL12 exacerbated oncogene-induced replication stress and sensitized cancer cells to drug-induced replication stress by WEE1 inhibition. Collectively, our results indicate that FBXL12 constitutes a vulnerability and a potential therapeutic target in CYCLIN E-overexpressing cancers.
When examining the formation energetics of a hydrogen-bonded complex R−X−H···Y−R‘, focus has been almost always on the atoms directly involved, namely the atoms X, Y, and H. Little attention has been ...paid to the effects of the secondary alkyl groups R and R'. Taking dimethyl sulfoxide (DMSO)−methanol binary system as an example, we have studied the roles of the alkyl groups in stabilizing the hydrogen bonds by employing FTIR and NMR techniques and quantum chemical calculations. We found that methyl groups play different roles in response to the hydrogen-bonding interactions. The methyl groups of DMSO are electron-donating, whereas that of methanol is electron-withdrawing, both making positive contributions. The findings reveal non-negligible effects of secondary alkyl groups in hydrogen bonding interaction and may shed light on the understanding of other more complicated hydrogen-bonded systems in chemical and biological systems.
In systemic autoimmune diseases such as systemic lupus erythematosus (SLE), B cell tolerance is lost and there is a production of autoantibodies that drive pathology. The specificities of these ...antibodies are towards a wide range of autoantigens including proteins such as serum factors including cytokines as well as towards nucleic acids and modified glycolipids. It is known that endosomal pattern recognition receptors are involved in specific responses but if they drive specificity towards a specific group of autoantigens is not known. Here, we used syngeneic apoptotic cells alone to break B cell tolerance and investigated the antibody response in Unc93b1 mutant mice that lack signalling from the TLR3, TLR7 and TLR9 receptors. We found that specific B cell responses known from patients with SLE including antibodies towards Ro-52/60, La, cardiolipin as well as DNA were all significantly lower in the knockout mice. Thus, we found that endosomal TLR receptors were involved in break of tolerance and drive B cell responses for protein, nucleic acid and modified lipid antigens. This pinpoints these receptors as key drivers for the full range of antibody driven pathology in SLE and suggests that targeting of endosomal TLR driven responses will quench all B cell driven autoreactivity.
•Endosomal pattern recognition receptors (PRRs) are involved in break of tolerance to apoptotic cells.•Absence of endosomal PRRs lessens the antibody response to protein, nucleic acid and modified lipid self-antigens.•Reduced autoantibody production is dependent on B-cell intrinsic endosomal PRRs.
The mechanisms underlying chronic obstructive pulmonary disease (COPD) remain unclear. Genetic and genomic changes may play a significant role in the pathogenesis of COPD. Identification of ...differentially expressed genes and miRNAs and their regulatory mechanisms at the whole-genome level will provide a comprehensive understanding of the development of COPD.
Peripheral blood mononuclear cells (PBMCs) from 12 patients with COPD and 12 normal controls were examined at the miRNA and mRNA expression levels using Affymetrix GeneChip. Microarray data were analyzed with Affymetrix Transcriptome Analysis Console 2.0 and GeneSpring software. Gene interaction pathways of the differentially expressed genes and miRNA-mRNA regulation were analyzed using the Ingenuity Pathway Analysis software. Four differentially expressed genes and one miRNA were further confirmed using RT-qPCR.
One hundred and thirty-three upregulated and 973 downregulated genes were identified in PBMCs of patients with COPD. Pathway analysis on the differentially expressed genes in COPD revealed significant enrichment in IL-8 signaling and iCOS-iCOSL signaling in T helper cells. Seventy-seven upregulated miRNAs and 43 downregulated miRNAs were differentially expressed between PBMCs from patients with COPD and normal controls. Among these 120 differentially expressed miRNAs, 42 miRNAs targeting 28 upregulated genes and 69 miRNAs targeting 498 downregulated genes were identified. The expression of CXCR1, HBEGF, TREM-1, and hsa-miR-148a-3p was more elevated in patients with COPD than in normal controls, whereas NFAT5 was decreased.
miRNAs and mRNAs are differentially expressed in PBMCs of patients with COPD, compared with normal controls. miRNAs regulate the expression of mRNAs, and thus play a role in the pathogenesis of COPD. Investigating these relationships may provide further insight into the mechanisms of COPD.
MCM-41/ZSM-5 composites were prepared using a dual templating method through a process of two-step crystallization. Mesoporous MCM-41 was first synthesized using the self-assembling of surfactant ...cetyltrimethylammonium bromide and subsequently the amorphous wall of MCM-41 was recrystallized with a structure-directing agent tetrapropylammonium bromide, which was introduced into the MCM-41 wall through a pretreatment process. A solid to solid-phase transformation mechanism was presented for the recrystallization of MCM-41 framework. Two kinds of stable MCM-41/ZSM-5 composites can be synthesized during the course of recrystallization. Crystallized mesoporous MCM-41 containing only short-range ordered ZSM-5 structure was first synthesized in the early stage of the recrystallization. With the increase of recrystallization time, some discrete micron-sized ZSM-5 crystals were produced and firmly attached to the loose aggregates of crystallized MCM-41, and another kind of MCM-41/ZSM-5 composite containing interconnected mesopore and micropore was therefore obtained. Because of improved acidity and a 2-fold pore system, both MCM-41/ZSM-5 composites are more advantageous than amorphous MCM-41 and a mechanical mixture of MCM-41 and ZSM-5 in acid catalysis.
A novel automated apple surface defect sorting experimental system based on computer image technology has been developed. The hardware system has the advantage of being able to inspect simultaneously ...four sides of each apple on the sorting line. The methods, including image background removal, defects segmentation and identification for stem-end and calyx areas, were developed. The results show that the experimental hardware system is practical and feasible, and that the proposed algorithm of defect detection is effective.
MicroPET II is a newly developed PET (positron emission tomography) scanner designed for high-resolution imaging of small animals. It consists of 17,640 LSO crystals each measuring 0.975 x 0.975 x ...12.5 mm3, which are arranged in 42 contiguous rings, with 420 crystals per ring. The scanner has an axial field of view (FOV) of 4.9 cm and a transaxial FOV of 8.5 cm. The purpose of this study was to carefully evaluate the performance of the system and to optimize settings for in vivo mouse and rat imaging studies. The volumetric image resolution was found to depend strongly on the reconstruction algorithm employed and averaged 1.1 mm (1.4 microl) across the central 3 cm of the transaxial FOV when using a statistical reconstruction algorithm with accurate system modelling. The sensitivity, scatter fraction and noise-equivalent count (NEC) rate for mouse- and rat-sized phantoms were measured for different energy and timing windows. Mouse imaging was optimized with a wide open energy window (150-750 keV) and a 10 ns timing window, leading to a sensitivity of 3.3% at the centre of the FOV and a peak NEC rate of 235,000 cps for a total activity of 80 MBq (2.2 mCi) in the phantom. Rat imaging, due to the higher scatter fraction, and the activity that lies outside of the field of view, achieved a maximum NEC rate of 24,600 cps for a total activity of 80 MBq (2.2 mCi) in the phantom, with an energy window of 250-750 keV and a 6 ns timing window. The sensitivity at the centre of the FOV for these settings is 2.1%. This work demonstrates that different scanner settings are necessary to optimize the NEC count rate for different-sized animals and different injected doses. Finally, phantom and in vivo animal studies are presented to demonstrate the capabilities of microPET II for small-animal imaging studies.
We targeted LYN, a src-tyosine kinase involved in B-cell activation, in case-control association studies using populations of European-American, African-American and Korean subjects. Our combined ...European-derived population, consisting of 2463 independent cases and 3131 unrelated controls, shows significant association with rs6983130 in a female-only analysis with 2254 cases and 2228 controls (P=1.1 x 10(-4), odds ratio (OR)=0.81 (95% confidence interval: 0.73-0.90)). This single nucleotide polymorphism (SNP) is located in the 5' untranslated region within the first intron near the transcription initiation site of LYN. In addition, SNPs upstream of the first exon also show weak and sporadic association in subsets of the total European-American population. Multivariate logistic regression analysis implicates rs6983130 as a protective factor for systemic lupus erythematosus (SLE) susceptibility when anti-dsDNA, anti-chromatin, anti-52 kDa Ro or anti-Sm autoantibody status were used as covariates. Subset analysis of the European-American female cases by American College of Rheumatology classification criteria shows a reduction in the risk of hematological disorder with rs6983130 compared with cases without hematological disorders (P=1.5 x 10(-3), OR=0.75 (95% CI: 0.62-0.89)). None of the 90 SNPs tested show significant association with SLE in the African American or Korean populations. These results support an association of LYN with European-derived individuals with SLE, especially within autoantibody or clinical subsets.
PDF