Publications by authors named "Meng Chen"

808 Publications

STAT1 epigenetically regulates LCP2 and TNFAIP2 by recruiting EP300 to contribute to the pathogenesis of inflammatory bowel disease.

Clin Epigenetics 2021 Jun 10;13(1):127. Epub 2021 Jun 10.

Department of Gastroenterology, Zhongnan Hospital, Wuhan University, Wuhan, 430071, Hubei, China.

Background: The aetiology of inflammatory bowel disease (IBD) is related to genetics and epigenetics. Epigenetic regulation of the pathogenesis of IBD has not been well defined. Here, we investigated the role of H3K27ac events in the pathogenesis of IBD. Based on previous ChIP-seq and RNA-seq assays, we studied signal transducer and activator of transcription 1 (STAT1) as a transcription factor (TF) and investigated whether the STAT1-EP300-H3K27ac axis contributes to the development of IBD. We performed ChIP-PCR to investigate the interaction between STAT1 and H3K27ac, and co-IP assays were performed to investigate the crosstalk between STAT1 and EP300.

Results: Lymphocyte cytosolic protein 2 (LCP2) and TNF-α-inducible protein 2 (TNFAIP2) are target genes of STAT1. p-STAT1 binds to the enhancer loci of the two genes where H3K27ac is enriched, and EP300 subsequently binds to regulate their expression. In mice with dextran sulfate sodium (DSS)-induced acute colitis, an EP300 inhibitor significantly inhibited colitis.

Conclusions: p-STAT1 and EP300 promote TNFAIP2 and LCP2 expression through an increase in H3K27ac enrichment on their enhancers and contribute to the pathogenesis of chronic inflammation.
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http://dx.doi.org/10.1186/s13148-021-01101-wDOI Listing
June 2021

The global, regional, and national burden of cancer among adolescents and young adults in 204 countries and territories, 1990-2019: a population-based study.

J Hematol Oncol 2021 Jun 9;14(1):89. Epub 2021 Jun 9.

Paediatric Dentistry and Orthodontics, Faculty of Dentistry, The University of Hong Kong, 34 Hospital Road, Pok Fu Lam, Hong Kong.

Background: Accurate appraisal of burden of adolescents and young adults (AYAs) cancers is crucial to informing resource allocation and policy making. We report on the latest estimates of burden of AYA cancers in 204 countries and territories between 1990 and 2019 in association with socio-demographic index (SDI).

Patients And Methods: Estimates from the Global Burden of Disease study 2019 were used to analyse incidence, mortality, and disability-adjusted life years (DALYs) due to AYA cancers at global, regional, and national levels by sex. Association between AYA cancer burden and SDI were investigated. Burdens of AYA cancers were contextualized in comparison with childhood and older adult cancers. All estimates are reported as counts and age-standardized rates per 100,000 person-years.

Results: In 2019, there were 1.2 million incident cases, 0.4 million deaths, and 23.5 million DALYs due to AYA cancers globally. The highest age-standardized incidence rate occurred in Western Europe (75.3 [Females] and 67.4 [Males] per 100,000 person-years). Age-standardized death (23.2 [Females] and 13.9 [Males] per 100,000 person-years) and DALY (1328.3 [Females] and 1059.2 [Males] per 100,000 person-years) rates were highest in Oceania. Increasing SDI was associated with a higher age-standardized incidence rate. An inverted U-shaped association was identified between SDI and death and DALY rates. AYA cancers collectively is the second leading cause of non-communicable diseases-related deaths globally in 2019. DALYs of AYA cancers ranked the second globally and the first in low and low-middle SDI locations when compared with that of childhood and older adult cancers.

Conclusion: The global burden of AYA cancers is substantial and disproportionally affect populations in limited-resource settings. Capacity building for AYA cancers is essential in promoting equity and population health worldwide.
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http://dx.doi.org/10.1186/s13045-021-01093-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8191013PMC
June 2021

Global, regional, and national burden of severe periodontitis, 1990-2019: an analysis of the Global Burden of Disease Study 2019.

J Clin Periodontol 2021 Jun 7. Epub 2021 Jun 7.

Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, Xi'an, China.

Aims: Up-to-date epidemiological studies on the global burden of severe periodontitis is scarce. This study aimed to present the latest estimates for prevalence of severe periodontitis from 1990 to 2019, by region, age, and level of socio-demographic development.

Materials And Methods: Estimates from the Global Burden of Disease study (GBD) 2019 were used to investigate burden and trends of prevalence of severe periodontitis and its association with socio-demographic development at global, regional, and national level. Decomposition analysis was performed to explore the contribution of demographic and epidemiological factors to the evolving burden of severe periodontitis.

Results: In 2019, there were 1.1 billion (95% uncertainty interval: 0.8 billion to 1.4 billion) prevalent cases of severe periodontitis globally. From 1990 to 2019, age-standardised prevalence rate of severe periodontitis increased 8.44% (6.62% to 10.59%) worldwide. Prevalence of severe periodontitis is higher among less developed countries/regions. Global population growth accounted for 67.9% of the increase in the number of prevalent cases of severe periodontitis from 1990 to 2019.

Conclusions: The global burden of severe periodontitis is substantial and increasing over the past three decades. Upstream policy changes are urgently needed to address the global public health challenge of severe periodontitis.
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http://dx.doi.org/10.1111/jcpe.13506DOI Listing
June 2021

Primary Osteocyte Supernatants Metabolomic Profiling of Two Transgenic Mice With Connexin43 Dominant Negative Mutants.

Front Endocrinol (Lausanne) 2021 18;12:649994. Epub 2021 May 18.

Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China.

Osteocytes could release some small molecules (≤ 1 kDa) through gap junctions and hemichannels to extracellular environment, such as prostaglandin E2 (PGE2), nitric oxide (NO) and adenosine triphosphate (ATP), which play key roles in transferring signals between bone cells and other tissue cells. Connexin (Cx) 43 is the most abundant connexin in osteocytes. To further discover molecules released by osteocytes through Cx43 channels and better understand the regulatory function of Cx43 channels in osteocytes, we performed non-targeted global metabolomics analysis using liquid chromatography-tandem mass spectrometry (LC-MS/MS) on conditioned medium collected from osteocytes isolated from two transgenic mouse models with Cx43 dominant negative mutants driven by a 10 kb-DMP1 promoter: R76W (gap junctions are blocked, whereas hemichannels are promoted) and Δ130-136 (both gap junctions and hemichannels are blocked). The results revealed that several new categories of molecules, such as "fatty acyls" and "carboxylic acids and derivatives", could be released through osteocytic Cx43 channels. In addition, alteration of Cx43 channel function affected the release of metabolites related to inflammatory reaction and oxidative stress. Pathway analysis further showed that citric acid cycle was the most differential metabolic pathway regulated by Cx43 channels. In sum, these results isolated new potential metabolites released by osteocytes through Cx43 channels, and offered a novel perspective to understand the regulatory mechanisms of osteocytes on themselves and other cells as well.
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http://dx.doi.org/10.3389/fendo.2021.649994DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8169970PMC
May 2021

Structure, Nanomechanical Properties, and Wettability of Organized Erucamide Layers on a Polypropylene Surface.

Langmuir 2021 Jun 20;37(21):6521-6532. Epub 2021 May 20.

School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, United Kingdom.

Understanding the nanostructure and nanomechanical properties of surface layers of erucamide, in particular the molecular orientation of the outermost layer, is important to its widespread use as a slip additive in polymer materials. Extending our recent observations of nanomorphologies of erucamide layers on a , here we evaluate its nanostructure on a . Atomic force microscopy (AFM) imaging revealed the molecular packing, thickness, and surface coverage of the erucamide layers, while peak force quantitative nanomechanical mapping (QNM) showed that erucamide reduced the adhesive response on polypropylene. Synchrotron X-ray reflectivity (XRR) was used to probe the out-of-plane structure of the surface layers. Static contact angle measurements further corroborated on the resulting wettability, also demonstrating the efficacy of erucamide physisorption in facilitating control over polypropylene surface wetting. The results show the formation of erucamide monolayers, bilayers and multilayers, depending on the concentration in the spin-cast solution. Correlation of AFM, XRR and wettability results consistently points to the molecular orientation in the outermost layer, i.e. with the erucamide tails pointing outward for the surface nanostructures with different morphologies (i.e., bilayers and multilayers). Rare occurrence of monolayers with exposed hydrophilic head groups were observed only at the lowest erucamide concentration. Compared with our previous observations on the hydrophilic surface, the erucamide surface coverage was much higher on the more hydrophobic propylene surface at similar erucamide concentrations in the spin-cast solution. Furthermore, the structure, molecular orientation and nanomechanical properties of the spin-cast erucamide multilayers atop polypropylene were also similar to those on industrially relevant polypropylene fibers coated with erucamide via . These findings shed light on the nanostructural features of the erucamide surface layer underpinning its nanomechanical properties, relevant to many applications in which erucamide is commonly used as a slip additive.
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http://dx.doi.org/10.1021/acs.langmuir.1c00686DOI Listing
June 2021

Propionate alleviates palmitic acid-induced endoplasmic reticulum stress by enhancing autophagy in calf hepatic cells.

J Dairy Sci 2021 May 14. Epub 2021 May 14.

Key Laboratory of Zoonosis, Ministry of Education, College of Veterinary Medicine, Jilin University, 5333 Xi'an Road, Changchun 130062, Jilin, China. Electronic address:

Negative energy balance-induced high blood concentrations of free fatty acids during the early postpartum period in dairy cows is a major cause of liver injury. Cows in severe negative energy balance often have suboptimal intakes of feed, which contributes to shortfalls in production of ruminal propionate and circulating glucose. Although increasing propionate production by the rumen through feed additives such as propylene glycol is effective in helping cows alleviate the shortfall in dietary energy supply, mechanisms whereby propionate affects liver function beyond gluconeogenesis are unknown. Therefore, the objective of this study was to investigate whether propionate could protect calf hepatic cells from palmitic acid (PA)-induced lipotoxicity and the underlying mechanisms. Calf hepatic cells were isolated from 5 healthy calves (1 d old, female, 30-40 kg, fasting) and treated with various concentrations of PA (0, 100, 200, or 400 μM) and propionate (0, 1, 2, or 4 mM) after being administered with or without autophagic inhibitor. Propionate enhanced autophagic activity in calf hepatic cells, as indicated by elevated expression of autophagy markers LC3-II (microtubule-associated protein 1 light chain 3-II, encoded by MAP1LC3) and decreased expression of SQSTM1 (sequestosome-1, also called p62). Conversely, PA suppressed autophagic activity and decreased cell viability, which was improved by propionate in calf hepatic cells. In addition, propionate decreased the phosphorylation of proteins EIF2AK3 (kinase R/PKR like ER kinase) and ERN1 (inositol-requiring enzyme 1α) and cleaved ATF6 (activating transcription factor 6) in PA-treated calf hepatic cells, indicating the suppression effect of propionate on endoplasmic reticulum (ER) stress. However, inhibition of autophagic activity by chloroquine or bafilomycin A1 impede the beneficial effects of propionate on ER stress and cell viability. These results demonstrated that propionate alleviates ER stress and elevates cell viability in PA-treated calf hepatic cells by enhancing autophagy, which implies that autophagy may be a promising target in improving liver injury of dairy cows during transition period.
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http://dx.doi.org/10.3168/jds.2020-19969DOI Listing
May 2021

Renal Denervation Attenuates Neuroinflammation in the Brain by Regulating Gut-Brain Axis in Rats With Myocardial Infarction.

Front Cardiovasc Med 2021 26;8:650140. Epub 2021 Apr 26.

Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.

The development of neuroinflammation deteriorates the prognosis of myocardial infarction (MI). We aimed to investigate the effect of renal denervation (RDN) on post-MI neuroinflammation in rats and the related mechanisms. Male adult Sprague-Dawley rats were subjected to sham or ligation of the left anterior descending coronary artery to induce MI. One week later, the MI rats received a sham or RDN procedure. Their cardiac functions were analyzed by echocardiography, and their intestinal structures, permeability, and inflammatory cytokines were tested. The intestinal microbiota were characterized by 16S rDNA sequencing. The degrees of neuroinflammation in the brains of rats were analyzed for microglia activation, inflammatory cytokines, and inflammation-related signal pathways. In comparison with the Control rats, the MI rats exhibited impaired cardiac functions, intestinal injury, increased intestinal barrier permeability, and microbial dysbiosis, accompanied by increased microglia activation and pro-inflammatory cytokine levels in the brain. A RDN procedure dramatically decreased the levels of renal and intestinal sympathetic nerve activity, improved cardiac functions, and mitigated the MI-related intestinal injury and neuroinflammation in the brain of MI rats. Interestingly, the RDN procedure mitigated the MI-increased intestinal barrier permeability and pro-inflammatory cytokines and plasma LPS as well as ameliorated the gut microbial dysbiosis in MI rats. The protective effect of RDN was not significantly affected by treatment with intestinal alkaline phosphatase but significantly reduced by L-phenylalanine treatment in MI rats. RDN attenuated the neuroinflammation in the brain of MI rats, associated with mitigating the MI-related intestinal injury.
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http://dx.doi.org/10.3389/fcvm.2021.650140DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8109795PMC
April 2021

Narratives of Prevention and Affliction in Type 2 Diabetes: Mechanisms of Influence in a Sample of Middle-aged Women.

J Health Commun 2021 May 4:1-11. Epub 2021 May 4.

Department of Communication, University of California, Davis, USA.

Research suggests that readers identify more with a competent protagonist who acts to prevent diabetes than with a less competent protagonist whose inaction leads to disease. We sought a better understanding of the mediators of this protagonist competence effect. Middle-aged women (45-55) read a prevention narrative depicting a protagonist at risk for type 2 diabetes (T2D) who prevents diabetes through lifestyle changes or an affliction narrative in which protagonist inaction leads to disease ( = 315). The prevention narrative elicited more identification than the affliction narrative for participants at low risk of T2D, but less identification for higher risk participants. Identification's impact on intentions to adopt self-protective behaviors was partially mediated by self-referencing. Protagonist competence did not affect transportation, but transportation had a direct effect on behavioral intentions and an indirect effect on intentions mediated by self-referencing. Fear arousal predicted behavioral intentions and was highest among those who read the affliction narrative and rated self as at risk for T2D. Protagonist competence had an indirect effect on intentions mediated by attributions of trustworthiness in response to the affliction narrative. This study contributes to our understanding of how narratives work and underscores the importance of tailoring narratives to the risk profile of individuals.
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http://dx.doi.org/10.1080/10810730.2021.1913678DOI Listing
May 2021

Preparation of (R)-3-aminopiperidine by resolution with optically active cyclic phosphoric acids.

Chirality 2021 07 3;33(7):379-384. Epub 2021 May 3.

College of Chemical and Pharmaceutical Engineering, Hebei University of Science and Technology, Shijiazhuang, China.

(R)-3-aminopiperidine ((R)-APD), a key intermediate for alogliptin, trelagliptin, and linagliptin, was successfully resolved from racemic 3-aminopiperidine with an enantiomerically pure resolving agent, namely, (R)-4-(2-chlohydroxy-1.3.2-dioxaphosphorinane 2-oxide ((R)-CPA), via diastereomeric salt formation. By this resolution approach, (R)-3-aminopiperidine was obtained in 99.5% yield with 99.6%e.e.
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http://dx.doi.org/10.1002/chir.23312DOI Listing
July 2021

Systematic analysis of migration factors by MigExpress identifies essential cell migration control genes in non-small cell lung cancer.

Mol Oncol 2021 May 2. Epub 2021 May 2.

Division of Cancer Research, Department of Thoracic Surgery, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, German Cancer Consortium (DKTK) - Partner Site Freiburg, Germany.

Cell migration is an essential process in health and in disease, including cancer metastasis. A comprehensive inventory of migration factors is nonetheless lacking-in part due to the difficulty in assessing migration using high-throughput technologies. Hence, there are currently very few screens that systematically reveal factors controlling cell migration. Here, we introduce MigExpress as a platform for the 'identification of Migration control genes by differential Expression'. MigExpress exploits the combination of in-depth molecular profiling and the robust quantitative analysis of migration capacity in a broad panel of samples and identifies migration-associated genes by their differential expression in slow- versus fast-migrating cells. We applied MigExpress to investigate non-small cell lung cancer (NSCLC), which is the most frequent cause of cancer mortality mainly due to metastasis. In 54 NSCLC cell lines, we comprehensively determined mRNA and protein expression. Correlating the transcriptome and proteome profiles with the quantified migration properties led to the discovery and validation of FLNC, DSE, CPA4, TUBB6, and BICC1 as migration control factors in NSCLC cells, which were also negatively correlated with patient survival. Notably, FLNC was the least expressed filamin in NSCLC, but the only one controlling cell migration and correlating with patient survival and metastatic disease stage. In our study, we present MigExpress as a new method for the systematic analysis of migration factors and provide a comprehensive resource of transcriptomic and proteomic data of NSCLC cell lines related to cell migration.
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http://dx.doi.org/10.1002/1878-0261.12973DOI Listing
May 2021

Disengagement of light responses in by localized developmental factors.

Authors:
Meng Chen

Proc Natl Acad Sci U S A 2021 May;118(21)

Department of Botany and Plant Sciences, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521

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http://dx.doi.org/10.1073/pnas.2106291118DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8166078PMC
May 2021

1,8-cineole ameliorates ischaemic brain damage via TRPC6/CREB pathways in rats.

J Pharm Pharmacol 2021 Jun;73(7):979-985

Department of Anesthesiology, Taihe Hospital, Hubei University of Medicine, Shiyan, Hubei, China.

Objectives: A previous in vitro study reported that the monoterpene oxide 1,8-cineole (cineole) attenuates neuronal caused by oxygen-glucose deprivation/reoxygenation in culture. However, to date, there is no in vivo evidence showing neuroprotective effects of cineole against stroke. This study aimed to investigate whether cineole attenuates cerebral ischaemic damage in rats.

Methods: A rat model of middle cerebral artery occlusion (MCAO) followed by 24 h reperfusion was applied. Male rats were treated with oral cineole (100 mg/kg) for 7 consecutive days, then subjected to MCAO surgery. Infarct volume, neurologic deficits, apoptosis and expression levels of all-spectrin breakdown products of 145 kDa (SBDP145), transient receptor potential canonical (subtype) 6 (TRPC6) and phosphorylated CREB (p-CREB) were measured in ischaemic brain tissues.

Key Findings: Cineole treatment significantly reduced infarct volume, neurological dysfunction, neuronal apoptosis, SBDP145 formation and TRPC6 degradation and enhanced p-CREB expression in MCAO rats compared with vehicle treatment. These neuroprotective effects were markedly suppressed by pharmacological inhibition of MEK or CaMKIV signalling.

Conclusions: Our study provides in vivo evidence demonstrating that cineole pretreatment attenuates ischaemic stroke-induced brain damage, mainly through blocking calpain-induced TRPC6 degradation and activating CREB via MEK/CREB and CaMKIV/CREB signalling pathways.
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http://dx.doi.org/10.1093/jpp/rgab035DOI Listing
June 2021

Systematic evaluation of the effect of polyadenylation signal variants on the expression of disease-associated genes.

Genome Res 2021 May 19;31(5):890-899. Epub 2021 Apr 19.

State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Human Phenome Institute, School of Life Sciences and Huashan Hospital, Fudan University, Shanghai, 200438, China.

Single nucleotide variants (SNVs) within polyadenylation signals (PASs), a specific six-nucleotide sequence required for mRNA maturation, can impair RNA-level gene expression and cause human diseases. However, there is a lack of genome-wide investigation and systematic confirmation tools for identifying PAS variants. Here, we present a computational strategy to integrate the most reliable resources for discovering distinct genomic features of PAS variants and also develop a credible and convenient experimental tool to validate the effect of PAS variants on expression of disease-associated genes. This approach will greatly accelerate the deciphering of PAS variation-related human diseases.
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http://dx.doi.org/10.1101/gr.270256.120DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8092010PMC
May 2021

High circulating insulin-like growth factor-1 reduces the risk of renal cell carcinoma: a Mendelian randomization study.

Carcinogenesis 2021 Apr 14. Epub 2021 Apr 14.

Departments of Epidemiology, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States.

Insulin and insulin-like growth factors play important roles in carcinogenesis. Circulating insulin-like growth factor-1 (IGF-1) and insulin-like growth factor-binding protein-3 (IGFBP-3) have been linked to cancer susceptibility. The associations of circulating IGF-1 and IGFBP-3 with the risk of renal cell carcinoma (RCC) are inconsistent. Recent large genome-wide association studies (GWAS) have identified 413 single nucleotide polymorphisms (SNPs) associated with IGF-1 and 4 SNPs associated with IGFBP-3. In this large case control study consisting of 2,069 RCC patients and 2,052 healthy controls of European ancestry, we used a two-sample Mendelian randomization (MR) approach to investigate the associations of genetically predicted circulating IGF-1 and IGFBP-3 with RCC risk. We used an individual level data-based genetic risk score (GRS) and a summary statistics-based inverse-variance weighting (IVW) method in MR analyses. We found that genetically predicted IGF-1 was significantly associated with RCC risk in both the GRS analysis (OR =0.43 per SD increase, 95% CI, 0.34-0.53) and the IVW analysis (OR = 0.46 per SD increase, 95% CI, 0.37-0.57). Dichotomized at the median GRS value of IGF-1 in controls, individuals with high GRS had a 45% reduced RCC risk (OR=0.55, 95% CI, 0.48-0.62) compared to those with low GRS. Genetically predicted circulating IGFBP-3 was not associated with RCC risk. This is the largest RCC study of circulating IGF-1 and IGFBP-3 to date and our data suggest a strong inverse relationship between circulating IGF-1 level and RCC risk.
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http://dx.doi.org/10.1093/carcin/bgab031DOI Listing
April 2021

Wire fracture in postoperative Nuss procedure: a problem that cannot be ignored.

Transl Pediatr 2021 Mar;10(3):569-578

Department of pediatrics, Chongqing University Three Gorges Hospital, Chongqing, China.

Background: Surgical stainless wire has been widely used to stabilize pectus bar and ribs in Nuss procedure for pectus excavatum correction. However, wire fracture and its secondary complications are problems easily to be ignored but very important. The purpose of this article was to describe a series of cases with wire breakage, hoping to arouse the attention of worldwide thoracic surgeons to this potential threat, and to share our modifications on the fixation patterns and materials in Nuss procedure.

Methods: From September 2011 to January 2020, 44 patients underwent Nuss procedure at Chongqing University Three Gorges Hospital. In the initial 25 patients (Group A), each bar was secured by stainless wires, and the latter 19 patients (Group B) received stainless wires and polyblend polyethylene sutures (PDS) in the bar fixation. Patient demographics, Haller index (HI), wire fracture rate, characteristics of the broken wires, and operation time were recorded.

Results: The mean operation age was 8.1±4.3 years in group A and 10.4±2.9 years in group B. There was no statistical difference in HIs between the two groups (P>0.05). The wire fracture occurred in 88.0% of the patients in Group A, while the wires in Group B were all intact. There was no bar displacement or other serious complication requiring surgical intervention in the two groups. The mean operation time of bar removal when encountering wire fracture was 104.6±42.8 minutes, which was significantly higher than that in Group B (P≤0.001).

Conclusions: The wire fracture in the bar fixation could pose potential hazards to patients deserving special attention from thoracic surgeons. Cancel the wire fixation in the non-stabilizer side while simultaneously using wires and PDS in the pectus bar fixation may achieve the pectus bar stability while overcoming the problem of wire fracture.
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http://dx.doi.org/10.21037/tp-20-354DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8039790PMC
March 2021

Peroxiredoxin alleviates the fitness costs of imidacloprid resistance in an insect pest of rice.

PLoS Biol 2021 Apr 12;19(4):e3001190. Epub 2021 Apr 12.

State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, Guangdong, China.

Chemical insecticides have been heavily employed as the most effective measure for control of agricultural and medical pests, but evolution of resistance by pests threatens the sustainability of this approach. Resistance-conferring mutations sometimes impose fitness costs, which may drive subsequent evolution of compensatory modifier mutations alleviating the costs of resistance. However, how modifier mutations evolve and function to overcome the fitness cost of resistance still remains unknown. Here we show that overexpression of P450s not only confers imidacloprid resistance in the brown planthopper, Nilaparvata lugens, the most voracious pest of rice, but also leads to elevated production of reactive oxygen species (ROS) through metabolism of imidacloprid and host plant compounds. The inevitable production of ROS incurs a fitness cost to the pest, which drives the increase or fixation of the compensatory modifier allele T65549 within the promoter region of N. lugens peroxiredoxin (NlPrx) in the pest populations. T65549 allele in turn upregulates the expression of NlPrx and thus increases resistant individuals' ability to clear the cost-incurring ROS of any source. The frequent involvement of P450s in insecticide resistance and their capacity to produce ROS while metabolizing their substrates suggest that peroxiredoxin or other ROS-scavenging genes may be among the common modifier genes for alleviating the fitness cost of insecticide resistance.
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http://dx.doi.org/10.1371/journal.pbio.3001190DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8062100PMC
April 2021

RCB initiates Arabidopsis thermomorphogenesis by stabilizing the thermoregulator PIF4 in the daytime.

Nat Commun 2021 04 6;12(1):2042. Epub 2021 Apr 6.

Department of Botany and Plant Sciences, Institute for Integrative Genome Biology, University of California, Riverside, CA, USA.

Daytime warm temperature elicits thermomorphogenesis in Arabidopsis by stabilizing the central thermoregulator PHYTOCHROME INTERACTING transcription FACTOR 4 (PIF4), whose degradation is otherwise promoted by the photoreceptor and thermosensor phytochrome B. PIF4 stabilization in the light requires a transcriptional activator, HEMERA (HMR), and is abrogated when HMR's transactivation activity is impaired in hmr-22. Here, we report the identification of a hmr-22 suppressor mutant, rcb-101, which surprisingly carries an A275V mutation in REGULATOR OF CHLOROPLAST BIOGENESIS (RCB). rcb-101/hmr-22 restores thermoresponsive PIF4 accumulation and reverts the defects of hmr-22 in chloroplast biogenesis and photomorphogenesis. Strikingly, similar to hmr, the null rcb-10 mutant impedes PIF4 accumulation and thereby loses the warm-temperature response. rcb-101 rescues hmr-22 in an allele-specific manner. Consistently, RCB interacts directly with HMR. Together, these results unveil RCB as a novel temperature signaling component that functions collaboratively with HMR to initiate thermomorphogenesis by selectively stabilizing PIF4 in the daytime.
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http://dx.doi.org/10.1038/s41467-021-22313-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8024306PMC
April 2021

miR-98-5p inhibits gastric cancer cell stemness and chemoresistance by targeting branched-chain aminotransferases 1.

Life Sci 2021 Jul 31;276:119405. Epub 2021 Mar 31.

State Key Laboratory of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, PR China. Electronic address:

Aims: Gastric cancer stem cells (GCSCs) have been used as a therapeutic target. This study aims to estimate the role of miR-98-5p (termed miR-98) in the development of GCSCs.

Main Methods: The expression of miR-98 in CD44 GCSCs was verified by RT-PCR. The miR-98 was overexpressed in CD44 GCSCs by Lentivirus. The ability of self-renewal, invasion, chemoresistance and tumorigenicity was detected in vitro or in vivo after overexpression of miR-98. The target genes of miR-98 were predicted and verified by luciferase reporter assays. The effects miR-98/BCAT1 signaling on the chemoresistance and tumorigenicity of CD44 GCSCs were investigated in a xenograft model by rescue experiments.

Key Findings: We have shown that miR-98 was decreased in CD44 GCSCs. The overexpression of miR-98 could inhibit the expression of stem-related genes and the ability of self-renewal, invasion, and tumorigenicity of GCSCs. Also, we found that miR-98 overexpression enhances the sensitivity to cisplatin treatment in vitro. Using a xenograft model, we showed that miR-98 overexpression reversed paclitaxel resistance to CD44 GCSCs. Finally, we found that branched-chain aminotransferases 1 (BCAT1) is a target gene of miR-98. Overexpressed BCAT1 reversed xenograft tumor formation ability and attenuated the paclitaxel chemosensitivity induced by miR-98 downregulation. Furthermore, BCAT1 restoration affected the expression of invasion and drug resistance-related genes.

Significance: This study revealed miR-98 inhibits gastric cancer cell stemness and chemoresistance by targeting BCAT1, suggesting that this miR-98/BCAT1 axis represents a potential therapeutic target in gastric cancer.
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http://dx.doi.org/10.1016/j.lfs.2021.119405DOI Listing
July 2021

Cervical cerclage in twin pregnancies: An updated systematic review and meta-analysis.

Eur J Obstet Gynecol Reprod Biol 2021 May 20;260:137-149. Epub 2021 Mar 20.

West China Second Hospital, Sichuan University, Department of Gynecology and Obstetrics, Chengdu, 610041, China; West China Second Hospital, Sichuan University, Key Laboratory of Obstetrics and Gynecologic and Pediatric Diseases and Birth Defects of Ministry of Education, Chengdu, 610041, China. Electronic address:

Objective: Data on the prevention of preterm birth in twin pregnancies with cervical cerclage remain inconsistent. Thus, this study aimed to comprehensively evaluate the value of cervical cerclage as a treatment strategy to prevent preterm birth in twin pregnancies with regard to both maternal and neonatal outcomes.

Study Design: In this systematic review and meta-analysis, the PubMed, Cochrane Library, Medline, EMBASE, and Web of Science databases were searched for relevant studies and trials from their inception up to December 2020. Outcomes were expressed as risk ratios and standardized mean differences in a meta-analysis model using STATA 15.0 software.

Results: The search included 944 studies, 15 of which were eligible for inclusion, representing 726 patients treated with cervical cerclage and 8578 non-cerclage treatment controls. When the cervical length was <15 mm, the risk ratio of preterm birth at <37 weeks (0.77, p = 0.01), <34 weeks (0.58, p = 0.002), and <32 weeks (0.61, p = 0.024) of gestation in the cerclage group was significantly lower than that in the non-cerclage group.

Conclusion: For twin pregnancies with a cervical length <15 mm, cervical cerclage was associated with significant reduction in preterm birth.
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http://dx.doi.org/10.1016/j.ejogrb.2021.03.013DOI Listing
May 2021

Maternal exposure to phenanthrene during gestation disturbs glucose homeostasis in adult mouse offspring.

Chemosphere 2021 May 14;270:128635. Epub 2020 Oct 14.

State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, PR China. Electronic address:

Epidemiological studies have indicated that polycyclic aromatic hydrocarbons were related to diabetes and insulin resistance. However, studies in mammals on the development of diabetes caused by polycyclic aromatic hydrocarbons are lacking. Pregnant mice were orally exposed to phenanthrene (0, 60 and 600 μg kg body weight) once every 3 days during gestation. In adult mouse offspring, in-utero phenanthrene exposure caused glucose intolerance and decreased insulin levels in females, while caused elevated fasting blood glucose and insulin levels in males. Serum resistin and interleukin-6 levels were elevated in offspring of both sexes. Serum adiponectin levels were decreased in females but increased in males. The insulin receptor signals were upregulated in the liver and downregulated in the skeletal muscle of F1 females, while they were inhibited in both tissues of F1 males. The visceral fat weight and body weight of the treated mice were not increased, suggesting that phenanthrene is not an obesogen, which is supported by the nonsignificant alteration in pparγ transcription in visceral adipose tissue. The transcription of retn in visceral adipose tissue was upregulated in both sexes, and that of adipoq was downregulated in females but upregulated in males, which were matched with the promoter methylation levels of these genes. The results indicated that phenanthrene exposure during gestation could disturb adipocytokine levels via epigenetic modification in adult offspring, and further influence glucose metabolism. These results might be helpful for understanding nonobesogenic pollutant-induced insulin resistance and preventing against diabetes without obesity.
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http://dx.doi.org/10.1016/j.chemosphere.2020.128635DOI Listing
May 2021

Reconstruction and analysis of correlation networks based on GC-MS metabolomics data for hypercholesterolemia.

Biochem Biophys Res Commun 2021 May 20;553:1-8. Epub 2021 Mar 20.

The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, 710049, Shaan xi, China. Electronic address:

Background And Aims: Hypercholesterolemia is characterized by the elevation of plasma total cholesterol level, especially low-density lipoprotein (LDL) cholesterol. This disease is usually caused by a mutation in genes such as LDL receptor, apolipoprotein B, or proprotein convertase subtilisin/kexin type 9. However, a considerable number of patients with hypercholesterolemia do not have any mutation in these candidate genes. In this study, we examined the difference in the metabolic level between patients with hypercholesterolemia and healthy subjects, and screened the potential biomarkers for this disease.

Methods: Analysis of plasma metabolomics in hypercholesterolemia patients and healthy controls was performed by gas chromatography-mass spectrometry and metabolic correlation networks were constructed using Gephi-0.9.2.

Results: First, metabolic profile analysis confirmed the distinct metabolic footprints between the patients and the healthy ones. The potential biomarkers screened by orthogonal partial least-squares discrimination analysis included l-lactic acid, cholesterol, phosphoric acid, d-glucose, urea, and d-allose (Variable importance in the projection > 1). Second, arginine and methionine metabolism were significantly perturbed in hypercholesterolemia patients. Finally, we identified that l-lactic acid, l-lysine, l-glutamine, and l-cysteine had high scores of centrality parameters in the metabolic correlation network.

Conclusion: Plasma l-lactic acid could be used as a sensitive biomarker for hypercholesterolemia. In addition, arginine biosynthesis and cysteine and methionine metabolism were profoundly altered in patients with hypercholesterolemia.
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http://dx.doi.org/10.1016/j.bbrc.2021.03.069DOI Listing
May 2021

Osthole enhances the immunosuppressive effects of bone marrow-derived mesenchymal stem cells by promoting the Fas/FasL system.

J Cell Mol Med 2021 May 21;25(10):4835-4845. Epub 2021 Mar 21.

Northern Department of Endodontics, Stomatological Hospital of Chongqing Medical University, Chongqing, China.

Thanks to the advantages of easy harvesting and escape from immune rejection, autologous bone marrow-derived mesenchymal stem cells (BMSCs) are promising candidates for immunosuppressive therapy against inflammation and autoimmune diseases. However, the therapy is still challenging because the immunomodulatory properties of BMSCs are always impaired by immunopathogenesis in patients. Because of its reliable and extensive biological activities, osthole has received increased clinical attention. In this study, we found that BMSCs derived from osteoporosis donors were ineffective in cell therapy for experimental inflammatory colitis and osteoporosis. In vivo and in vitro tests showed that because of the down-regulation of Fas and FasL expression, the ability of osteoporotic BMSCs to induce T-cell apoptosis decreased. Through the application of osthole, we successfully restored the immunosuppressive ability of osteoporotic BMSCs and improved their treatment efficacy in experimental inflammatory colitis and osteoporosis. In addition, we found the immunomodulatory properties of BMSCs were enhanced after osthole pre-treatment. In this study, our data highlight a new approach of pharmacological modification (ie osthole) to improve the immune regulatory performance of BMSCs from a healthy or inflammatory microenvironment. The development of targeted strategies to enhance immunosuppressive therapy using BMSCs may be significantly improved by these findings.
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http://dx.doi.org/10.1111/jcmm.16459DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8107110PMC
May 2021

KDM4A-mediated histone demethylation of SLC7A11 inhibits cell ferroptosis in osteosarcoma.

Biochem Biophys Res Commun 2021 04 6;550:77-83. Epub 2021 Mar 6.

Department of Musculoskeletal Surgery, Fudan University Shanghai Cancer Center, Shanghai Medical College, Fudan University, Shanghai, 200032, China. Electronic address:

Osteosarcoma (OS) is the most common type of bone tumor that seriously affects limb function and induces great pain in patients. Lung metastasis and chemotherapy resistance are two key issues leading to the poor prognosis of OS patients, therefore new treatment targets and strategies are urgently needed. In our study, we uncovered the role of histone demethylase KDM4A in regulating OS cell ferroptosis and tumor progression. KDM4A was significantly upregulated in OS specimens and high KDM4A expression was associated with poorer prognosis in OS patients. Our data indicated that targeting KDM4A significantly increased OS cell death, enhanced cisplatin response, and attenuated migration ability in vitro. KDM4A depletion dramatically inhibited tumor progression and lung metastasis of OS in vivo Further experiments confirmed that KDM4A knockdown promoted OS cell ferroptosis, a special non-apoptotic form of cell death. KDM4A regulates SLC7A11 transcription and OS cell ferroptosis by controlling H3K9me3 demethylation in the promoter region of SLC7A11. Our findings deepened the recognition of epigenetic regulatory mechanism in OS tumorigenesis, chemoresistance, and metastasis, suggesting that KDM4A activity may be a potential therapeutic target for future OS treatment.
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http://dx.doi.org/10.1016/j.bbrc.2021.02.137DOI Listing
April 2021

A meta-analysis of the impact of point of view on narrative processing and persuasion in health messaging.

Psychol Health 2021 Mar 6:1-18. Epub 2021 Mar 6.

Department of Communication, University of California, Davis, CA, USA.

Objective: To synthesize experimental research on the impact of narrative point of view (POV) on message processing and persuasion outcomes in health promotion. Moderators examined included characteristics of study design, participants, and experimental stimuli.

Design And Main Outcome Measures: Random effects model meta-analysis of 16 health promotion experiments, using the package in R. Studies included compared the effects of first- and third-person POV on risk perceptions, attitudes, behavioral intention, identification and transportation.

Results: There was no evidence of publication bias. Narratives told in the first-person POV led to higher levels of perceived susceptibility ( = 0.10, 95% CI [0.01, 0.20]) and identification feelings ( = 0.10, 95% CI [0.10, 0.21]) than third-person narratives. The effects of first-person POV narratives were significantly stronger for stories that were written in the past-tense and that depicted the protagonist as being similar to message recipients.

Conclusion: Findings support a theoretical model of POV impact in which a first-person perspective increases identification with the character, thereby leading to higher levels of perceived susceptibility to the health threat. The practical implication is that the effectiveness of narrative persuasion is enhanced by using the first-person point of view, emphasizing target audience-protagonist similarities, and telling stories in the past tense.
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http://dx.doi.org/10.1080/08870446.2021.1894331DOI Listing
March 2021

KDM6B-mediated histone demethylation of LDHA promotes lung metastasis of osteosarcoma.

Theranostics 2021 6;11(8):3868-3881. Epub 2021 Feb 6.

Department of Orthopedics, The Eighth Affiliated Hospital of Sun Yat-sen University, Shenzhen 518003, China.

Osteosarcoma (OS), the most common type of bone tumor, which seriously affects the patients' limb function and life quality. OS has a strong tendency of lung metastasis, and the five-year survival rate of patients with metastatic osteosarcoma is less than 20%. Thus, new treatment targets and strategies are urgently needed. The expression of the histone demethylase KDM6B and H3K27me3 levels in OS specimens were analyzed using quantitative PCR and immunohistochemical assays. The biological functions of KDM6B were determined using transwell, wound healing assays, and an orthotopic injection-induced lung metastasis model. Subsequently, chromatin immunoprecipitation sequencing (ChIP-seq) combined with transcriptomic RNA sequencing (RNA-seq), and subsequent ChIP-qPCR, western blot, and aerobic glycolysis assays were used to explore the mechanism of KDM6B function and validate the candidate target gene of KDM6B. KDM6B expression was significantly upregulated in OS patients, and high KDM6B expression was associated with poorer prognosis in OS patients. Targeting KDM6B significantly inhibited OS cell migration and lung metastasis . RNA-seq and ChIP-seq analysis revealed that KDM6B increases lactate dehydrogenase LDHA expression in OS cells by directly mediating H3K27me3 demethylation. The phenotypes of inhibited cell metastasis in KDM6B-knockdown OS cells was reversed upon overexpression of LDHA. Finally, a small molecule inhibitor targeting KDM6B significantly inhibited OS cell migration and lung metastasis . Collectively, we elucidated that upregulated KDM6B facilitates tumor metastasis in OS via modulating LDHA expression. Our findings deepen the recognition of OS metastasis mechanism and suggest that KDM6B might be a new potential therapeutic target for the treatment of OS (especially highly metastatic OS).
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http://dx.doi.org/10.7150/thno.53347DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7914357PMC
February 2021

Media Exposure to COVID-19 Predicted Acute Stress: A Moderated Mediation Model of Intolerance of Uncertainty and Perceived Social Support.

Front Psychiatry 2020 10;11:613368. Epub 2021 Feb 10.

School of Psychology, Guizhou Normal University, Guiyang, China.

Previous studies have found that disaster-related media exposure could predict acute stress responses. However, few studies have investigated the relationship between media exposure to COVID-19 and acute stress, and less is known about the mechanisms that translate media exposure to COVID-19 into acute stress. The current study explored the impact of media exposure to COVID-19 on acute stress, and examined the mediating role of intolerance of uncertainty (IU) and the moderating role of perceived social support (PSS). A total of 1,483 Chinese participants ( = 27.93 years, = 8.45) completed anonymous online questionnaires regarding media exposure to COVID-19, IU, PSS, and acute stress during the COVID-19 outbreak in China. Media exposure to COVID-19 was positively related to acute stress, and IU partially mediated this relationship. The direct effect of media exposure to COVID-19 on acute stress, and the relationship between IU and acute stress, were both moderated by PSS. The impacts of both media exposure to COVID-19 and IU on acute stress were stronger for individuals with low PSS. This study collected data in a shorter timeframe, and no assessments occurred during the follow-up, which may prevent us from detecting the changes of the relationships between variables over time. Meanwhile, the self-report method limited the validity of the data due to subjective reporting bias. These findings contribute to a better understanding of how and when pandemic-related media exposure affects acute stress, and provide new perspectives for the prevention to reduce psychological problems following traumatic events.
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http://dx.doi.org/10.3389/fpsyt.2020.613368DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7902691PMC
February 2021

Seroepidemiology of pertussis in China: A population-based, cross-sectional study.

Vaccine 2021 03 26;39(12):1687-1692. Epub 2021 Feb 26.

Department of Immunization and Prevention, Beijing Center for Disease Prevention and Control, Beijing Research Center for Preventive Medicine, Beijing 100013, China. Electronic address:

Background: Despite high pertussis vaccination coverage and significant decrease of pertussis since the adoption of the Expanded Programme on Immunization (1978), increased pertussis incidence has been reported in China from 2013 to 2017. This study aimed at evaluating the immune response to pertussis among vaccinated children and beyond in China.

Methods: The study recruited 2 144 healthy subjects. Serum IgG antibodies against pertussis toxin (anti-PT IgG) were measured by ELISA. Anti-PT IgG concentration (GMC), seropositivity rate (GMC ≥ 40 IU/ml), and recent infection rate (GMC > 100 IU/ml) were calculated. Participants ≤ 2 years-old were further stratified by vaccination schedule intervals and participants ≤ 6 years-old by vaccine used (Domestic DTaP or DTaP-IPV//PRP ~ T (Pentaxim, SP)).

Results: Among 0-6-year-olds, the anti-PT IgG GMC was 5.99 IU/ml (95%CI 5.39-6.67). The GMC increased in accordance with the primary vaccination series (4-6 months) and the toddler booster (18-23 months), and continuously declined thereafter to its nadir at 6 years-old [3.72 IU/ml (95%CI 2.91-4.77)]. GMCs were markedly higher in those vaccinated with DTaP-IPV/PRP ~ T compared to DTaP. In individuals > 6 years-old, the GMC was 5.67 IU/ml (95%CI 5.36-6.00), the seropositivity rate was 6.7% (95%CI 5.5-7.9) and the recent infection rate was 1.2% (95%CI 0.7-1.7). The seropositivity rates increased from 6 years-old and peaked at 9 years-old (10.3% [95%CI 0.7-19.8]).

Conclusions: Vaccination against pertussis increases anti-PT IgG, but wanes over time. The sero-estimated infection rates increase from school age and peak at about 9 years-old. These results support the addition of a booster of pertussis vaccine at preschool age.
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http://dx.doi.org/10.1016/j.vaccine.2021.02.032DOI Listing
March 2021

Homologies between SARS-CoV-2 and allergen proteins may direct T cell-mediated heterologous immune responses.

Sci Rep 2021 02 26;11(1):4792. Epub 2021 Feb 26.

Institute of Laboratory Medicine, Universities of Giessen and Marburg Lung Center (UGMLC), Philipps University Marburg, German Center for Lung Research (DZL), Marburg, Germany.

The outbreak of the new severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is a public health emergency. Asthma does not represent a risk factor for COVID-19 in several published cohorts. We hypothesized that the SARS-CoV-2 proteome contains T cell epitopes, which are potentially cross-reactive to allergen epitopes. We aimed at identifying homologous peptide sequences by means of two distinct complementary bioinformatics approaches. Pipeline 1 included prediction of MHC Class I and Class II epitopes contained in the SARS-CoV-2 proteome and allergens along with alignment and elaborate ranking approaches. Pipeline 2 involved alignment of SARS-CoV-2 overlapping peptides with known allergen-derived T cell epitopes. Our results indicate a large number of MHC Class I epitope pairs including known as well as de novo predicted allergen T cell epitopes with high probability for cross-reactivity. Allergen sources, such as Aspergillus fumigatus, Phleum pratense and Dermatophagoides species are of particular interest due to their association with multiple cross-reactive candidate peptides, independently of the applied bioinformatic approach. In contrast, peptides derived from food allergens, as well as MHC class II epitopes did not achieve high in silico ranking and were therefore not further investigated. Our findings warrant further experimental confirmation along with examination of the functional importance of such cross-reactive responses.
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http://dx.doi.org/10.1038/s41598-021-84320-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7910599PMC
February 2021

Hierarchical structure in poly(N-vinyl carbazole)/FeO nanocomposites and the relevant magnetic coercivity.

Soft Matter 2021 Mar 24;17(11):3055-3067. Epub 2021 Feb 24.

Department of Chemical Engineering, National Chung Hsing University, Taichung 402, Taiwan.

In this study, we report the dependence of the nanoparticle dispersion on the zero-conversion initiator efficiency in the nanocomposites formed by poly(N-vinyl carbazole) (PNVK) and acrylic acid-modified iron oxide (AA-FeO) nanoparticles via free radical solution polymerization of the precursor solution, that is, a thorough mixture of 28.5 wt% AA-FeO nanoparticles and the N-vinyl carbazole (NVK) monomer with the solvent dimethylformamide and azobisisobutyronitrile as an initiator. Here three different types of the dispersion state of AA-FeO nanoparticles in the PNVK matrix have been distinguished by a combined approach of transmission electron microscopy and small-angle X-ray scattering coupled with real-space models of the nanoparticle assemblies. When the polymerization proceeded with a higher zero-conversion initiator efficiency (f°) by pre-polymerization at 115 °C, the generation of a large amount of free radicals could efficiently induce the dominant surface-initiated polymerization of the NVK monomer with the vinyl groups of tethered acrylic acids; in this case, the constitution of "shorter multiple grafted PNVK chains" threaded AA-FeO nanoparticles to form particle branches and the branches were joined together from branching points along each branch, thereby forming the network structure. However, once the polymerization was conducted at a lower f° by pre-polymerization at 75 °C, a significant reduction in the generation of free radicals likely greatly reduced the efficiency in the occurrence of surface-initiated polymerization at particle surfaces; nevertheless, the self-polymerization of the NVK monomer could still take place to induce a local demixing between the polymerizing longer PNVK chains and AA-FeO nanoparticles via the attractive depletion mechanism, thus locally leading to the formation of small aggregates. While if the f° was controlled to be intermediate by polymerization at 100 °C, an optimal balance between the rates of the surface-initiated polymerization and the self-polymerization induced a collective construction built from the network and aggregate structures, exhibiting the structural characteristics of large aggregates. Furthermore, the magnetic coercivity of PNVK/AA-FeO nanocomposites was found to depend on the dispersion state of the AA-FeO nanoparticles, presenting a tendency towards enhanced coercivity as the dispersion state changed from large aggregates to small aggregates to network structure.
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http://dx.doi.org/10.1039/d0sm02275fDOI Listing
March 2021

Robust Microflow LC-MS/MS for Proteome Analysis: 38 000 Runs and Counting.

Anal Chem 2021 03 17;93(8):3686-3690. Epub 2021 Feb 17.

Chair of Proteomics and Bioanalytics, Technical University of Munich, Emil Erlenmeyer Forum 5, 85354 Freising, Germany.

Microflow liquid chromatography tandem mass spectrometry (μLC-MS/MS) is becoming a viable alternative to nanoflow LC-MS/MS for the analysis of proteomes. We have recently demonstrated the potential of such a system operating with a 1 mm i.d. × 150 mm column and at a flow rate of 50 μL/min for high-throughput applications. On the basis of the analysis of ∼38 000 samples measured on two instruments over the past two years, we now show that the approach is extremely robust. Up to 1500 analyses were performed within one month, and >14 000 samples could be analyzed on a single column without loss of chromatographic performance. Samples included proteomes of cell lines, tissues, and human body fluids, which were analyzed with or without prior peptide fractionation or stable isotope labeling. We show that the μLC-MS/MS system is capable of measuring 2600 proteins from undepleted human plasma and ∼5000 proteins from crude human urine in 1 day, demonstrating its potential for in-depth as well as high-throughput clinical application.
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http://dx.doi.org/10.1021/acs.analchem.1c00257DOI Listing
March 2021