A polymorphic p53 response element in KIT ligand influences cancer risk and has undergone natural selection.

The ability of p53 to regulate transcription is crucial for tumor suppression and implies that inherited polymorphisms in functional p53-binding sites could influence cancer. Here, we identify a polymorphic p53 responsive element and demonstrate its influence on cancer risk using genome-wide data sets of cancer susceptibility loci, genetic variation, p53 occupancy, and p53-binding sites. We uncover a single-nucleotide polymorphism (SNP) in a functional p53-binding site and establish its influence on the ability of p53 to bind to and regulate transcription of the KITLG gene. The SNP resides in KITLG and associates with one of the largest risks identified among cancer genome-wide association studies. We establish that the SNP has undergone positive selection throughout evolution, signifying a selective benefit, but go on to show that similar SNPs are rare in the genome due to negative selection, indicating that polymorphisms in p53-binding sites are primarily detrimental to humans.

Epigenome-wide association study of lung cancer among never smokers in two prospective cohorts in Shanghai, China.

BACKGROUND: The aetiology of lung cancer among individuals who never smoked remains elusive, despite 15% of lung cancer cases in men and 53% in women worldwide being unrelated to smoking. Epigenetic alterations, particularly DNA methylation (DNAm) changes, have emerged as potential drivers. Yet, few prospective epigenome-wide association studies (EWAS), primarily focusing on peripheral blood DNAm with limited representation of never smokers, have been conducted. METHODS: We conducted a nested case-control study of 80 never-smoking incident lung cancer cases and 83 never-smoking controls within the Shanghai Women's Health Study and Shanghai Men's Health Study. DNAm was measured in prediagnostic oral rinse samples using Illumina MethylationEPIC array. Initially, we conducted an EWAS to identify differentially methylated positions (DMPs) associated with lung cancer in the discovery sample of 101 subjects. The top 50 DMPs were further evaluated in a replication sample of 62 subjects, and results were pooled using fixed-effect meta-analysis. RESULTS: Our study identified three DMPs significantly associated with lung cancer at the epigenome-wide significance level of p<8.22×10-8. These DMPs were identified as cg09198866 (MYH9; TXN2), cg01411366 (SLC9A10) and cg12787323. Furthermore, examination of the top 1000 DMPs indicated significant enrichment in epithelial regulatory regions and their involvement in small GTPase-mediated signal transduction pathways. Additionally, GrimAge acceleration was identified as a risk factor for lung cancer (OR=1.19 per year; 95% CI 1.06 to 1.34). CONCLUSIONS: While replication in a larger sample size is necessary, our findings suggest that DNAm patterns in prediagnostic oral rinse samples could provide novel insights into the underlying mechanisms of lung cancer in never smokers.

A prospective study of smoking-related white blood cell DNA methylation markers and risk of bladder cancer.

Bladder cancer, a common neoplasm, is primarily caused by tobacco smoking. Epigenetic alterations including DNA methylation have the potential to be used as prospective markers of increased risk, particularly in at-risk populations such as smokers. We aimed to investigate the potential of smoking-related white blood cell (WBC) methylation markers to contribute to an increase in bladder cancer risk prediction over classical questionnaire-based smoking metrics (i.e., duration, intensity, packyears) in a nested case-control study within the prospective prostate, lung, colorectal, and ovarian (PLCO) Cancer Screening Trial and the alpha-tocopherol, beta-carotene cancer (ATBC) Prevention Study (789 cases; 849 controls). We identified 200 differentially methylated sites associated with smoking status and 28 significantly associated (after correction for multiple testing) with bladder cancer risk among 2670 previously reported smoking-related cytosine-phosphate-guanines sites (CpGs). Similar patterns were observed across cohorts. Receiver operating characteristic (ROC) analyses indicated that cg05575921 (AHHR), the strongest smoking-related association we identified for bladder cancer risk, alone yielded similar predictive performance (AUC: 0.60) than classical smoking metrics (AUC: 0.59-0.62). Best prediction was achieved by including the first principal component (PC1) from the 200 smoking-related CpGs alongside smoking metrics (AUC: 0.63-0.65). Further, PC1 remained significantly associated with elevated bladder cancer risk after adjusting for smoking metrics. These findings suggest DNA methylation profiles reflect aspects of tobacco smoke exposure in addition to those captured by smoking duration, intensity and packyears, and/or individual susceptibility relevant to bladder cancer etiology, warranting further investigation.

An African-specific polymorphism in the TP53 gene impairs p53 tumor suppressor function in a mouse model.

A nonsynonymous single-nucleotide polymorphism at codon 47 in TP53 exists in African-descent populations (P47S, rs1800371; referred to here as S47). Here we report that, in human cell lines and a mouse model, the S47 variant exhibits a modest decrease in apoptosis in response to most genotoxic stresses compared with wild-type p53 but exhibits a significant defect in cell death induced by cisplatin. We show that, compared with wild-type p53, S47 has nearly indistinguishable transcriptional function but shows impaired ability to transactivate a subset of p53 target genes, including two involved in metabolism:Gls2(glutaminase 2) and Sco2 We also show that human and mouse cells expressing the S47 variant are markedly resistant to cell death by agents that induce ferroptosis (iron-mediated nonapoptotic cell death). We show that mice expressing S47 in homozygous or heterozygous form are susceptible to spontaneous cancers of diverse histological types. Our data suggest that the S47 variant may contribute to increased cancer risk in individuals of African descent, and our findings highlight the need to assess the contribution of this variant to cancer risk in these populations. These data also confirm the potential relevance of metabolism and ferroptosis to tumor suppression by p53.

Three-Dimensional Hierarchical Seaweed-Derived Carbonaceous Network with Designed g-C3N4 Nanosheets: Preparation and Mechanism Insight for 4-Nitrophenol Photoreduction.

The development of g-C3N4-based photocatalysts with abundant active sites is of great significance for photocatalytic reactions. Herein, a smart and robust strategy was presented to fabricate three-dimensional (3D) g-C3N4 nanosheet-coated alginate-based hierarchical porous carbon (g-C3N4@HPC), including coating melamine on calcium alginate (CA) hydrogel beads, freeze-drying hydrogel beads as well as pyrolysis at high temperatures. The resulting photocatalyst possessed a significantly high surface area and a large amount of interconnected macropores compared with porous carbon without the melamine coating. The unique structural features could effectively inhibit the curling and agglomeration of g-C3N4 nanosheets, provide abundant photocatalytic active sites, and promote mass diffusion. Therefore, the g-C3N4@HPC composite exhibited remarkable photocatalytic activity and outstanding stability toward the photoreduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) by NaBH4 under natural sunlight and simulated visible-light irradiation (λ > 420 nm) using a 300 W xenon lamp. Moreover, the mechanism toward the photocatalytic reaction was extensively studied by quenching experiments and electron spin resonance (ESR) experiments. The results showed that active hydrogen species were able to be achieved by following a dual-channel pathway in the NaBH4 system, which included photocatalytic reduction of H+ ions and photocatalytic oxidation of BH4- ions. This work not only opens up a new way to design efficient photocatalysts for various reactions but also provides a reference for an in-depth study of the photoreduction mechanism.

Mesorhizobium huakuii HtpG Interaction with nsLTP AsE246 Is Required for Symbiotic Nitrogen Fixation.

Plant nonspecific lipid transfer proteins (nsLTPs) are involved in a number of biological processes including root nodule symbiosis. However, the role of nsLTPs in legume-rhizobium symbiosis remains poorly understood, and no rhizobia proteins that interact with nsLTPs have been reported to date. In this study, we used a bacteria two-hybrid system and identified the high temperature protein G (HtpG) from Mesorhizobium huakuii that interacts with the nsLTP AsE246. The interaction between HtpG and AsE246 was confirmed by far-Western blotting and bimolecular fluorescence complementation. Our results indicated that the heat shock protein 90 (HSP90) domain of HtpG mediates the HtpG-AsE246 interaction. Immunofluorescence assay showed that HtpG was colocalized with AsE246 in infected nodule cells and symbiosome membranes. Expression of the htpG gene was relatively higher in young nodules and was highly expressed in the infection zones. Further investigation showed that htpG expression affects lipid abundance and profiles in root nodules and plays an essential role in nodule development and nitrogen fixation. Our findings provide further insights into the functional mechanisms behind the transport of symbiosome lipids via nsLTPs in root nodules.

Algoriphagus lacus sp. nov., isolated from a freshwater lake.

A Gram-stain-negative, non-motile, rod-shaped, oxidase-positive, red-pigmented bacterium, strain N3T, was isolated from Fuxian lake, a freshwater lake in Yunnan Province, PR China. Strain N3T was facultatively anaerobic, heterotrophic and negative for catalase. Optimal growth occurred at 30 °C (range 4-45 °C), pH 7.0-8.0 (range 6.5-9.5) and in the presence of 0-3 % (w/v) NaCl (range 0-3 %). The results of phylogenetic analysis based on 16S rRNA gene sequencing revealed that strain N3T was close to the type strains of Algoriphagus aquaeductus, Algoriphagus shivajiensis and Algoriphagus alkaliphilus with sequence similarities of 97.4, 97.3 and 97.2 % respectively. The G+C content of the genomic DNA was 43.9 mol%. The quinone system contained menaquinone MK-7 as the sole component. The major fatty acids were iso-C15 : 0, summed feature 9 (10-methyl C16 : 0 and/or iso-C17 : 1 ω9c), summed feature 3 (C16 : 1 ω6c and/or C16 : 1 ω 7c) and iso-C16 : 0. Major polar lipids were phosphatidylcholine, phosphatidylethanolamine, an unidentified glycolipid, one unidentified phospholipid, two unidentified aminolipids and four unidentified lipids. On the basis of physiological, chemotaxonomic and molecular properties as well as phylogenetic distinctiveness, strain N3T should be placed into the genus Algoriphagus as a novel species, for which the name Algoriphagus lacus sp. nov. is proposed. The type strain is N3T (=KCTC 62622T=MCCC 1H00308T).

Crohn's disease IRGM risk alleles are associated with altered gene expression in human tissues.

Crohn's disease (CD) is a chronic inflammatory gastrointestinal disorder. Genetic association studies have implicated dysregulated autophagy in CD. Among risk loci identified are a promoter single nucleotide polymorphism (SNP)( rs13361189 ) and two intragenic SNPs ( rs9637876 , rs10065172 ) in immunity-related GTPase family M ( IRGM) a gene that encodes a protein of the autophagy initiation complex. All three SNPs have been proposed to modify IRGM expression, but reports have been divergent and largely derived from cell lines. Here, analyzing RNA-Sequencing data of human tissues from the Genotype-Tissue Expression Project, we found that rs13361189 minor allele carriers had reduced IRGM expression in whole blood and terminal ileum, and upregulation in ileum of ZNF300P1, a locus adjacent to IRGM on chromosome 5q33.1 that encodes a long noncoding RNA. Whole blood and ileum from minor allele carriers had altered expression of multiple additional genes that have previously been linked to colitis and/or autophagy. Notable among these was an increase in ileum of LTF (lactoferrin), an established fecal inflammatory biomarker of CD, and in whole blood of TNF, a key cytokine in CD pathogenesis. Last, we confirmed that risk alleles at all three loci associated with increased risk for CD but not ulcerative colitis in a case-control study. Taken together, our findings suggest that genetically encoded IRGM deficiency may predispose to CD through dysregulation of inflammatory gene networks. Gene expression profiling of disease target tissues in genetically susceptible populations is a promising strategy for revealing new leads for the study of molecular pathogenesis and, potentially, for precision medicine. NEW & NOTEWORTHY Single nucleotide polymorphisms in immunity-related GTPase family M ( IRGM), a gene that encodes an autophagy initiation protein, have been linked epidemiologically to increased risk for Crohn's disease (CD). Here, we show for the first time that subjects with risk alleles at two such loci, rs13361189 and rs10065172 , have reduced IRGM expression in whole blood and terminal ileum, as well as dysregulated expression of a wide array of additional genes that regulate inflammation and autophagy.

Sulforaphane enriched transcriptome of lung mitochondrial energy metabolism and provided pulmonary injury protection via Nrf2 in mice.

Nrf2 is essential to antioxidant response element (ARE)-mediated host defense. Sulforaphane (SFN) is a phytochemical antioxidant known to affect multiple cellular targets including Nrf2-ARE pathway in chemoprevention. However, the role of SFN in non-malignant airway disorders remain unclear. To test if pre-activation of Nrf2-ARE signaling protects lungs from oxidant-induced acute injury, wild-type (Nrf2+/+) and Nrf2-deficient (Nrf2-/-) mice were given SFN orally or as standardized broccoli sprout extract diet (SBE) before hyperoxia or air exposure. Hyperoxia-induced pulmonary injury and oxidation indices were significantly reduced by SFN or SBE in Nrf2+/+ mice but not in Nrf2-/- mice. SFN upregulated a large cluster of basal lung genes that are involved in mitochondrial oxidative phosphorylation, energy metabolism, and cardiovascular protection only in Nrf2+/+ mice. Bioinformatic analysis elucidated ARE-like motifs on these genes. Transcript abundance of the mitochondrial machinery genes remained significantly higher after hyperoxia exposure in SFN-treated Nrf2+/+ mice than in SFN-treated Nrf2-/- mice. Nuclear factor-κB was suggested to be a central molecule in transcriptome networks affected by SFN. Minor improvement of hyperoxia-caused lung histopathology and neutrophilia by SFN in Nrf2-/- mice implies Nrf2-independent or alternate effector mechanisms. In conclusion, SFN is suggested to be as a preventive intervention in a preclinical model of acute lung injury by linking mitochondria and Nrf2. Administration of SFN alleviated acute lung injury-like pathogenesis in a Nrf2-dependent manner. Potential AREs in the SFN-inducible transcriptome for mitochondria bioenergetics provided a new insight into the downstream mechanisms of Nrf2-mediated pulmonary protection.

Aquiflexum aquatile sp. nov., isolated from lake water.

A Gram-stain-negative, facultative anaerobic, red-coloured, rod-shaped, non-flagellated, non-motile and non-gliding bacterium, designated strain Z0201T, was isolated from lake water in Yunnan, China (26° 16' N, 99° 94' E). Cells of strain Z0201T were 0.2-0.4 µm wide and 1.4-2.5 µm long, catalase-positive and oxidase-negative. Strain Z0201T was found to grow at 4-37 °C (optimum, 30 °C) and pH 6.5-8.5 (pH 7.5) in the presence of 0-2.0 % (w/v) NaCl (0-0.5 %). The sole respiratory quinone of strain Z0201T was MK-7 and the DNA G+C content was 41.2 mol%. The major fatty acid was iso-C15 : 0 (49.4 %). The polar lipid profile of strain Z0201T consisted of aminophospholipid, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol, phosphatidylethanolamine, two unidentified phospholipids and five unidentified lipids. Based on the 16S rRNA gene sequence analysis, strain Z0201T was a member of the genus Aquiflexum, appearing to be closely related to Aquiflexum balticum (95.4 %). On the basis of phenotypic distinctiveness and phylogenetic divergence, strain Z0201T is considered to represent a novel species of the genus Aquiflexum, for which the name Aquiflexumaquatile sp. nov. is proposed. The type strain is Z0201T (=KCTC 62450T=MCCC 1H00328T).

Jannaschia formosa sp. nov., isolated from marine saltern sediment.

A novel blush-red-pigmented, Gram-stain-negative, gliding, aerobic and rod- or oval-shaped bacterium, designated strain 12N15T, was isolated from sediment sampled at a marine saltern located in Wendeng, China (36° 59' 56.49″ N, 122° 1' 38.84″ E). Growth was observed at 10-40 °C (optimum, 28 °C), in 1.0-12.0 % NaCl (2.0-5.0 %, w/v) and at pH 6.0-9.5 (pH 7.0). The respiratory quinones were determined to be Q-10 and major fatty acids were C18 : 1ω7c and C18 : 0. The polar lipids profile of strain 12N15T included phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, aminolipid, phosphatidylcholine, one lipid and three phospholipids. The genomic DNA G+C content was 69.6 mol%. Phylogenetic analyses based on the 16S rRNA gene showed that the strain 12N15T was affiliated within the genus Jannaschia, and was most closely related to Jannaschia seohaensis KCTC 22172T. The average amino acid identity and percentage of conserved protein values between strain 12N15T and the type strain of the type species, Jannaschia helgolandensis DSM 14858T, were 70.2 % and 64.1 %, respectively. The average nucleotide identity value between strain 12N15T and J.annaschia seohaensis KCTC 22172T was 81.9 %. The phenotypic, phylogenetic and genomic analyses supported the hypothesis that strain 12N15T represents a novel species of the genus Jannaschia, for which the name Jannaschia formosa sp. nov. is proposed. The type strain is 12N15T (=MCCC 1H00325T=KCTC 62582T).

Aliidiomarina celeris sp. nov., isolated from coastal sediment.

A Gram-stain-negative, heterotrophic, facultative anaerobic, gliding and motile bacterium, approximately 0.6-0.9 µm wide and 1.5-2.6 µm long, designated F3105T, was isolated from a marine sediment sample collected along the coast of Rongcheng, China . The growth of strain F3105T occurred on media with 1.0-8.0 % (w/v) NaCl (optimum, 2.0-3.0 %) and a pH of 6.5-9.5 (optimum, pH 7.5) at 4-45 °C (optimum, 37 °C). The phylogenetic analysis of the 16S rRNA gene and chemotaxonomic data revealed that the isolate belonged to the genus Aliidiomarina, and is closely related to Aliidiomarina shirensis (95.9 % sequence similarity). The sole isoprenoid quinone was Q-8. The major cellular fatty acids of the isolate were iso-C15 : 0, iso-C17 : 1ω9c and iso-C17 : 0, and its polar lipids consisted of phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, aminolipid, two unidentified lipids and two unidentified aminophospholipids. The DNA G+C content of strain F3105T was 49.5 mol%. On the basis of phenotypic distinctiveness and phylogenetic divergence, strain F3105T is considered to represent a novel species of the genus Aliidiomarina, for which the name Aliidiomarinaceleris sp. nov. is proposed. The type strain is F3105T (=MCCC 1H00223T=KCTC 52891T).

Halioglobus lutimaris sp. nov., isolated from coastal sediment.

A novel Gram-stain-negative, strictly aerobic, non-flagellated and rod-shaped bacterium, designated HF004T, was isolated from a marine sediment sample collected from the coast of Weihai, China. The strain grew optimally at 28 °C, pH 7.5-8.0 and in the presence of 2.0-3.0 % (w/v) NaCl. Based on the 16S rRNA gene sequence analysis, strain HF004T was a member of the genus Halioglobus, appearing to be closely related to Halioglobus pacificus (96.1 %) and Halioglobus japonicus (95.6 %). The major fatty acids were summed feature 3 (i.e. C16 : 1ω7c and/or iso-C15 : 0 2-OH), C17 : 1ω8c and C18 : 1ω7c. The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol. The predominant respiratory quinone was Q-8. The DNA G+C content was 57.2 mol%. Cells of strain HF004T were rod-shaped and formed circular, mucous and beige-pigmented colonies on marine agar after incubation for 72 h at 28 °C. On the basis of phenotypic, genotypic and phylogenetic evidence, strain HF004T is presented as a novel species, for which the name Halioglobus lutimaris sp. nov. is proposed. The type strain is HF004T (=KCTC 42395T=MCCC 1H00127T).

Algoriphagus formosus sp. nov., isolated from coastal sediment.

A Gram-stain negative, facultative anaerobic, non-motile, strongly orange-pigmented and rod-shaped bacterium, designated XAY3209T, was isolated from a marine sediment sample collected from the coast of Weihai, China. Strain XAY3209T was found to grow optimally at 30 °C, at pH 7.0 and in the presence of 2.0% (w/v) NaCl. Its genomic DNA G+C content was 41.9 mol%. On the basis of 16S rRNA gene sequence similarity, the novel isolate belongs to the family Cyclobacteriaceae and is related to the genus Algoriphagus. It shares 98.1% 16S rRNA sequence identity with Algoriphagus marincola, its close phylogenetic relative, but did not show similarities more than 97% with other members of the genus Algoriphagus with validly published names. It contained menaquinone-7 (MK-7) as the sole respiratory quinone, iso-C15:0, iso-C17:1 ω9c and Summed feature 3 (C16:1 ω7c and/or iso-C15:0 2-OH) as the major fatty acids. The major polar lipids were phosphatidylethanolamine, one unidentified aminolipid, one unidentified phospholipid and five unidentified lipids. Results of physiological experiments, biochemical tests and genome average nucleotide identity value (with A. marincola MCCC 1F01203T) indicate that strain XAY3209T is genetically and phenotypically distinct from the species of the genus Algoriphagus with validly published names. Strain XAY3209T therefore represents a novel species, for which the name Algoriphagus formosus sp. nov. is proposed. The type strain is XAY3209T (= KCTC 52842T = MCCC 1H00189T).

Interactions of chromatin context, binding site sequence content, and sequence evolution in stress-induced p53 occupancy and transactivation.

Cellular stresses activate the tumor suppressor p53 protein leading to selective binding to DNA response elements (REs) and gene transactivation from a large pool of potential p53 REs (p53REs). To elucidate how p53RE sequences and local chromatin context interact to affect p53 binding and gene transactivation, we mapped genome-wide binding localizations of p53 and H3K4me3 in untreated and doxorubicin (DXR)-treated human lymphoblastoid cells. We examined the relationships among p53 occupancy, gene expression, H3K4me3, chromatin accessibility (DNase 1 hypersensitivity, DHS), ENCODE chromatin states, p53RE sequence, and evolutionary conservation. We observed that the inducible expression of p53-regulated genes was associated with the steady-state chromatin status of the cell. Most highly inducible p53-regulated genes were suppressed at baseline and marked by repressive histone modifications or displayed CTCF binding. Comparison of p53RE sequences residing in different chromatin contexts demonstrated that weaker p53REs resided in open promoters, while stronger p53REs were located within enhancers and repressed chromatin. p53 occupancy was strongly correlated with similarity of the target DNA sequences to the p53RE consensus, but surprisingly, inversely correlated with pre-existing nucleosome accessibility (DHS) and evolutionary conservation at the p53RE. Occupancy by p53 of REs that overlapped transposable element (TE) repeats was significantly higher (p<10-7) and correlated with stronger p53RE sequences (p<10-110) relative to nonTE-associated p53REs, particularly for MLT1H, LTR10B, and Mer61 TEs. However, binding at these elements was generally not associated with transactivation of adjacent genes. Occupied p53REs located in L2-like TEs were unique in displaying highly negative PhyloP scores (predicted fast-evolving) and being associated with altered H3K4me3 and DHS levels. These results underscore the systematic interaction between chromatin status and p53RE context in the induced transactivation response. This p53 regulated response appears to have been tuned via evolutionary processes that may have led to repression and/or utilization of p53REs originating from primate-specific transposon elements.

Mono- and Dinuclear Heteroleptic Cobalt Complexes with α-Diimine and Polyarene Ligands.

Reactions of the dimeric cobalt complex [(L(-) Co)2 ] (1, L=[(2,6-iPr2 C6 H3 )NC(Me)]2 ) with polyarenes afforded a series of mononuclear and dinuclear complexes: [LCo(η(4) -anthracene)] (2), [LCo(µ-η(4) :η(4) -naphthalene)CoL] (3), and [LCo(µ-η(4) :η(4) -phenanthrene)CoL] (4). The pyrene complexes [{Na2 (Et2 O)2 }{LCo(µ-η(3) :η(3) -pyrene)CoL}] (5) and [{Na2 (Et2 O)3 }{LCo(η(3) -pyrene)}] (6) were obtained by treating precursor 1 with pyrene followed by reduction with Na metal. These complexes contain three potential redox active centers: the cobalt metal and both α-diimine and polyarene ligands. Through a combination of X-ray crystallography, EPR spectroscopy, magnetic susceptibility measurement, and DFT computations, the electronic configurations of these complexes were studied. It was determined that complexes 2-4 have a high-spin Co(I) center coupled with a radical α-diimine ligand and a neutral polyarene ligand. Whereas, the ligand L in complexes 5 and 6 has been further reduced to the dianion, the cobalt remains in a formal (I) oxidation state, and the pyrene molecule is either neutral or monoanionic.

A genetic model of differential susceptibility to human respiratory syncytial virus (RSV) infection.

Respiratory syncytial virus (RSV) is the primary cause of lower respiratory tract infection during childhood and causes severe symptoms in some patients, which may cause hospitalization and death. Mechanisms for differential responses to RSV are unknown. Our objective was to develop an in vitro model of RSV infection to evaluate interindividual variation in response to RSV and identify susceptibility genes. Populations of human-derived HapMap lymphoblastoid cell lines (LCLs) were infected with RSV. Compared with controls, RSV-G mRNA expression varied from ~1- to 400-fold between LCLs. Basal expression of a number of gene transcripts, including myxovirus (influenza virus) resistance 1 (MX1), significantly correlated with RSV-G expression in HapMap LCLs. Individuals in a case-control population of RSV-infected children who were homozygous (n=94) or heterozygous (n=172) for the predicted deleterious A allele in a missense G/A SNP in MX1 had significantly greater risk for developing severe RSV disease relative to those with the major allele (n=108) (χ(2)=5.305, P=0.021; OR: 1.750, 95% CI: 1.110, 2.758, P=0.021). We conclude that genetically diverse human LCLs enable identification of susceptibility genes (e.g., MX1) for RSV disease severity in children, providing insight for disease risk.

Linking polymorphic p53 response elements with gene expression in airway epithelial cells of smokers and cancer risk.

Chronic cigarette smoking exposes airway epithelial cells to thousands of carcinogens, oxidants and DNA-damaging agents, creating a field of molecular injury in the airway and altering gene expression. Studies of cytologically normal bronchial epithelial cells from smokers have identified transcription-based biomarkers that may prove useful in early diagnosis of lung cancer, including a number of p53-regulated genes. The ability of p53 to regulate transcription is critical for tumor suppression, and this suggests that single-nucleotide polymorphisms (SNPs) in functional p53 binding sites (p53 response elements, or p53REs) that affect gene expression could influence susceptibility to cancer. To connect p53RE SNP genotype with gene expression and cancer risk, we identified a set of 204 SNPs in putative p53REs, and performed cis expression quantitative trait loci (eQTL) analysis, assessing associations between SNP genotypes and mRNA levels of adjacent genes in bronchial epithelial cells obtained from 44 cigarette smokers. To further test and validate these genotype-expression associations, we searched published eQTL studies from independent populations and determined that 53% (39/74) of the bronchial epithelial eQTLs were observed in at least one of other studies. SNPs in p53REs were also evaluated for effects on p53-DNA binding using a quantitative in vitro protein-DNA binding assay. Last, based on linkage disequilibrium, we found 6 p53RE SNPs associated with gene expression were identified as cancer risk SNPs by either genome-wide association studies or candidate gene studies. We provide an approach for identifying and evaluating potentially functional SNPs that may modulate the airway gene expression response to smoking and may influence susceptibility to cancers.

Identification of novel NRF2-regulated genes by ChIP-Seq: influence on retinoid X receptor alpha.

Cellular oxidative and electrophilic stress triggers a protective response in mammals regulated by NRF2 (nuclear factor (erythroid-derived) 2-like; NFE2L2) binding to deoxyribonucleic acid-regulatory sequences near stress-responsive genes. Studies using Nrf2-deficient mice suggest that hundreds of genes may be regulated by NRF2. To identify human NRF2-regulated genes, we conducted chromatin immunoprecipitation (ChIP)-sequencing experiments in lymphoid cells treated with the dietary isothiocyanate, sulforaphane (SFN) and carried out follow-up biological experiments on candidates. We found 242 high confidence, NRF2-bound genomic regions and 96% of these regions contained NRF2-regulatory sequence motifs. The majority of binding sites were near potential novel members of the NRF2 pathway. Validation of selected candidate genes using parallel ChIP techniques and in NRF2-silenced cell lines indicated that the expression of about two-thirds of the candidates are likely to be directly NRF2-dependent including retinoid X receptor alpha (RXRA). NRF2 regulation of RXRA has implications for response to retinoid treatments and adipogenesis. In mouse, 3T3-L1 cells' SFN treatment affected Rxra expression early in adipogenesis, and knockdown of Nrf2-delayed Rxra expression, both leading to impaired adipogenesis.

Spatial Chromosome Organization and Adaptation of Escherichia coli under Heat Stress.

The spatial organization of bacterial chromosomes is crucial for cellular functions. It remains unclear how bacterial chromosomes adapt to high-temperature stress. This study delves into the 3D genome architecture and transcriptomic responses of Escherichia coli under heat-stress conditions to unravel the intricate interplay between the chromosome structure and environmental cues. By examining the role of macrodomains, chromosome interaction domains (CIDs), and nucleoid-associated proteins (NAPs), this work unveils the dynamic changes in chromosome conformation and gene expression patterns induced by high-temperature stress. It was observed that, under heat stress, the short-range interaction frequency of the chromosomes decreased, while the long-range interaction frequency of the Ter macrodomain increased. Furthermore, two metrics, namely, Global Compactness (GC) and Local Compactness (LC), were devised to measure and compare the compactness of the chromosomes based on their 3D structure models. The findings in this work shed light on the molecular mechanisms underlying thermal adaptation and chromosomal organization in bacterial cells, offering valuable insights into the complex inter-relationships between environmental stimuli and genomic responses.