Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 320
Filtrar
1.
PLoS Comput Biol ; 17(2): e1008735, 2021 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-33577591

RESUMO

In this work, we introduce an entirely data-driven and automated approach to reveal disease-associated biomarker and risk factor networks from heterogeneous and high-dimensional healthcare data. Our workflow is based on Bayesian networks, which are a popular tool for analyzing the interplay of biomarkers. Usually, data require extensive manual preprocessing and dimension reduction to allow for effective learning of Bayesian networks. For heterogeneous data, this preprocessing is hard to automatize and typically requires domain-specific prior knowledge. We here combine Bayesian network learning with hierarchical variable clustering in order to detect groups of similar features and learn interactions between them entirely automated. We present an optimization algorithm for the adaptive refinement of such group Bayesian networks to account for a specific target variable, like a disease. The combination of Bayesian networks, clustering, and refinement yields low-dimensional but disease-specific interaction networks. These networks provide easily interpretable, yet accurate models of biomarker interdependencies. We test our method extensively on simulated data, as well as on data from the Study of Health in Pomerania (SHIP-TREND), and demonstrate its effectiveness using non-alcoholic fatty liver disease and hypertension as examples. We show that the group network models outperform available biomarker scores, while at the same time, they provide an easily interpretable interaction network.

2.
Nat Commun ; 12(1): 654, 2021 01 28.
Artigo em Inglês | MEDLINE | ID: mdl-33510174

RESUMO

Low muscle strength is an important heritable indicator of poor health linked to morbidity and mortality in older people. In a genome-wide association study meta-analysis of 256,523 Europeans aged 60 years and over from 22 cohorts we identify 15 loci associated with muscle weakness (European Working Group on Sarcopenia in Older People definition: n = 48,596 cases, 18.9% of total), including 12 loci not implicated in previous analyses of continuous measures of grip strength. Loci include genes reportedly involved in autoimmune disease (HLA-DQA1 p = 4 × 10-17), arthritis (GDF5 p = 4 × 10-13), cell cycle control and cancer protection, regulation of transcription, and others involved in the development and maintenance of the musculoskeletal system. Using Mendelian randomization we report possible overlapping causal pathways, including diabetes susceptibility, haematological parameters, and the immune system. We conclude that muscle weakness in older adults has distinct mechanisms from continuous strength, including several pathways considered to be hallmarks of ageing.


Assuntos
Predisposição Genética para Doença/genética , Estudo de Associação Genômica Ampla/métodos , Debilidade Muscular/genética , Sarcopenia/genética , Idoso , Idoso de 80 Anos ou mais , Envelhecimento/genética , Estudos de Coortes , Europa (Continente) , Feminino , Fator 5 de Diferenciação de Crescimento/genética , Cadeias alfa de HLA-DQ/genética , Humanos , Masculino , Pessoa de Meia-Idade , Força Muscular/genética , Força Muscular/fisiologia , Debilidade Muscular/fisiopatologia , Polimorfismo de Nucleotídeo Único , Sarcopenia/fisiopatologia
3.
Nat Genet ; 53(2): 147-155, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33462482

RESUMO

The intestinal microbiome is implicated as an important modulating factor in multiple inflammatory1,2, neurologic3 and neoplastic diseases4. Recent genome-wide association studies yielded inconsistent, underpowered and rarely replicated results such that the role of human host genetics as a contributing factor to microbiome assembly and structure remains uncertain5-11. Nevertheless, twin studies clearly suggest host genetics as a driver of microbiome composition11. In a genome-wide association analysis of 8,956 German individuals, we identified 38 genetic loci to be associated with single bacteria and overall microbiome composition. Further analyses confirm the identified associations of ABO histo-blood groups and FUT2 secretor status with Bacteroides and Faecalibacterium spp. Mendelian randomization analysis suggests causative and protective effects of gut microbes, with clade-specific effects on inflammatory bowel disease. This holistic investigative approach of the host, its genetics and its associated microbial communities as a 'metaorganism' broaden our understanding of disease etiology, and emphasize the potential for implementing microbiota in disease treatment and management.

4.
PLoS Genet ; 17(1): e1009092, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33481774

RESUMO

In order to adjust to changing environmental conditions, bacteria use nucleotide second messengers to transduce external signals and translate them into a specific cellular response. Cyclic di-adenosine monophosphate (c-di-AMP) is the only known essential nucleotide second messenger. In addition to the well-established role of this second messenger in the control of potassium homeostasis, we observed that glutamate is as toxic as potassium for a c-di-AMP-free strain of the Gram-positive model bacterium Bacillus subtilis. In this work, we isolated suppressor mutants that allow growth of a c-di-AMP-free strain under these toxic conditions. Characterization of glutamate resistant suppressors revealed that they contain pairs of mutations, in most cases affecting glutamate and potassium homeostasis. Among these mutations, several independent mutations affected a novel glutamate transporter, AimA (Amino acid importer A, formerly YbeC). This protein is the major transporter for glutamate and serine in B. subtilis. Unexpectedly, some of the isolated suppressor mutants could suppress glutamate toxicity by a combination of mutations that affect phospholipid biosynthesis and a specific gain-of-function mutation of a mechanosensitive channel of small conductance (YfkC) resulting in the acquisition of a device for glutamate export. Cultivation of the c-di-AMP-free strain on complex medium was an even greater challenge because the amounts of potassium, glutamate, and other osmolytes are substantially higher than in minimal medium. Suppressor mutants viable on complex medium could only be isolated under anaerobic conditions if one of the two c-di-AMP receptor proteins, DarA or DarB, was absent. Also on complex medium, potassium and osmolyte toxicity are the major bottlenecks for the growth of B. subtilis in the absence of c-di-AMP. Our results indicate that the essentiality of c-di-AMP in B. subtilis is caused by the global impact of the second messenger nucleotide on different aspects of cellular physiology.

5.
Int J Mol Sci ; 22(1)2021 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-33466458

RESUMO

The thyroid gland is both a thyroid hormone (TH) generating as well as a TH responsive organ. It is hence crucial that cathepsin-mediated proteolytic cleavage of the precursor thyroglobulin is regulated and integrated with the subsequent export of TH into the blood circulation, which is enabled by TH transporters such as monocarboxylate transporters Mct8 and Mct10. Previously, we showed that cathepsin K-deficient mice exhibit the phenomenon of functional compensation through cathepsin L upregulation, which is independent of the canonical hypothalamus-pituitary-thyroid axis, thus, due to auto-regulation. Since these animals also feature enhanced Mct8 expression, we aimed to understand if TH transporters are part of the thyroid auto-regulatory mechanisms. Therefore, we analyzed phenotypic differences in thyroid function arising from combined cathepsin K and TH transporter deficiencies, i.e., in Ctsk-/-/Mct10-/-, Ctsk-/-/Mct8-/y, and Ctsk-/-/Mct8-/y/Mct10-/-. Despite the impaired TH export, thyroglobulin degradation was enhanced in the mice lacking Mct8, particularly in the triple-deficient genotype, due to increased cathepsin amounts and enhanced cysteine peptidase activities, leading to ongoing thyroglobulin proteolysis for TH liberation, eventually causing self-thyrotoxic thyroid states. The increased cathepsin amounts were a consequence of autophagy-mediated lysosomal biogenesis that is possibly triggered due to the stress accompanying intrathyroidal TH accumulation, in particular in the Ctsk-/-/Mct8-/y/Mct10-/- animals. Collectively, our data points to the notion that the absence of cathepsin K and Mct8 leads to excessive thyroglobulin degradation and TH liberation in a non-classical pathway of thyroid auto-regulation.

6.
Elife ; 102021 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-33404502

RESUMO

The hydrothermal vent tubeworm Riftia pachyptila hosts a single 16S rRNA phylotype of intracellular sulfur-oxidizing symbionts, which vary considerably in cell morphology and exhibit a remarkable degree of physiological diversity and redundancy, even in the same host. To elucidate whether multiple metabolic routes are employed in the same cells or rather in distinct symbiont subpopulations, we enriched symbionts according to cell size by density gradient centrifugation. Metaproteomic analysis, microscopy, and flow cytometry strongly suggest that Riftia symbiont cells of different sizes represent metabolically dissimilar stages of a physiological differentiation process: While small symbionts actively divide and may establish cellular symbiont-host interaction, large symbionts apparently do not divide, but still replicate DNA, leading to DNA endoreduplication. Moreover, in large symbionts, carbon fixation and biomass production seem to be metabolic priorities. We propose that this division of labor between smaller and larger symbionts benefits the productivity of the symbiosis as a whole.

7.
J Proteomics ; 231: 104018, 2021 01 16.
Artigo em Inglês | MEDLINE | ID: mdl-33075551

RESUMO

Dilated cardiomyopathy (DCM) is characterized by ventricular chamber enlargement and impaired myocardial function. Endomyocardial biopsies (EMB) enable immunohistochemical and molecular characterization of this disease. However, knowledge about specific molecular patterns and their relation to cardiac function in both ventricles is rare. Therefore, we performed a mass spectrometric analysis of 28 paired EMBs of left (LV) and right ventricles (RV) of patients with DCM or suspected myocarditis allowing quantitative profiling of 743 proteins. We analysed associations between protein abundance of LV and RV as well as the echocardiographic parameters LVEF, TAPSE, LVEDDI, and RVEDDI by linear regression models. Overall, more LV than RV proteins were associated with LV parameters or with RVEDDI. Most LV and RV proteins increasing in level with impairing of LVEF were annotated to structural components of cardiac tissue. Additionally, a high proportion of LV proteins with metabolic functions decreased in level with decreasing LVEF. Results were validated with LV heart sections of a genetic murine heart failure model. The study shows, that remodelling and systolic dysfunction in DCM is mirrored by distinct alterations in protein composition of both ventricles. Loss of LV systolic function is reflected predominantly by alterations in proteins assigned to metabolic functions in the LV whereas structural remodelling was more obvious in the RV. Alterations related to intermediate filaments were seen in both ventricles and highlight such proteins as early indicators of LV loss of function. SIGNIFICANCE: The present study report protein sets in the RV and the LV being associated with ventricular function and remodelling in DCM. Protein abundances in the LV and the RV emphasize and expand current knowledge on pathophysiological changes in heart failure and DCM. While RV and LV EMBs do not differ concerning diagnostic assessment of inflammatory status and virus persistence, additional information reflecting disease severity associated protein alterations can be gained by EMB protein profiling. RV and LV protein data provided complementary information. The protein pattern of the LV reflects metabolic changes and an impaired energy production, which is associated with the degree of LV systolic dysfunction and remodelling and may yield important information about the disease status in DCM. On the other hand, at this disease stage of DCM with still preserved RV function, RV alterations in structural proteins may reflect myocardial compensatory protective mechanisms for maintenance of structure and cellular function. The study highlight particular proteins being of interest as heart failure biomarkers in both ventricles which seem to reflect the severity of the disease. Further comparative studies between different HF aetiologies have to evaluate those proteins as markers specific for DCM.

8.
PLoS One ; 15(11): e0230035, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33186364

RESUMO

BACKGROUND: Genome-wide association studies have identified multiple genomic loci associated with coronary artery disease, but most are common variants in non-coding regions that provide limited information on causal genes and etiology of the disease. To overcome the limited scope that common variants provide, we focused our investigation on low-frequency and rare sequence variations primarily residing in coding regions of the genome. METHODS AND RESULTS: Using samples of individuals of European ancestry from ten cohorts within the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium, both cross-sectional and prospective analyses were conducted to examine associations between genetic variants and myocardial infarction (MI), coronary heart disease (CHD), and all-cause mortality following these events. For prevalent events, a total of 27,349 participants of European ancestry, including 1831 prevalent MI cases and 2518 prevalent CHD cases were used. For incident cases, a total of 55,736 participants of European ancestry were included (3,031 incident MI cases and 5,425 incident CHD cases). There were 1,860 all-cause deaths among the 3,751 MI and CHD cases from six cohorts that contributed to the analysis of all-cause mortality. Single variant and gene-based analyses were performed separately in each cohort and then meta-analyzed for each outcome. A low-frequency intronic variant (rs988583) in PLCL1 was significantly associated with prevalent MI (OR = 1.80, 95% confidence interval: 1.43, 2.27; P = 7.12 × 10-7). We conducted gene-based burden tests for genes with a cumulative minor allele count (cMAC) ≥ 5 and variants with minor allele frequency (MAF) < 5%. TMPRSS5 and LDLRAD1 were significantly associated with prevalent MI and CHD, respectively, and RC3H2 and ANGPTL4 were significantly associated with incident MI and CHD, respectively. No loci were significantly associated with all-cause mortality following a MI or CHD event. CONCLUSION: This study identified one known locus (ANGPTL4) and four new loci (PLCL1, RC3H2, TMPRSS5, and LDLRAD1) associated with cardiovascular disease risk that warrant further investigation.

9.
Gut ; 2020 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-33168600

RESUMO

OBJECTIVE: The intestinal microbiome affects the prevalence and pathophysiology of a variety of diseases ranging from inflammation to cancer. A reduced taxonomic or functional diversity of the microbiome was often observed in association with poorer health outcomes or disease in general. Conversely, factors or manifest diseases that determine the long-term stability or instability of the microbiome are largely unknown. We aimed to identify disease-relevant phenotypes associated with faecal microbiota (in-)stability. DESIGN: A total of 2564 paired faecal samples from 1282 participants of the population-based Study of Health in Pomerania (SHIP) were collected at a 5-year (median) interval and microbiota profiles determined by 16S rRNA gene sequencing. The changes in faecal microbiota over time were associated with highly standardised and comprehensive phenotypic data to determine factors related to microbiota (in-)stability. RESULTS: The overall microbiome landscape remained remarkably stable over time. The greatest microbiome instability was associated with factors contributing to metabolic syndrome such as fatty liver disease and diabetes mellitus. These, in turn, were associated with an increase in facultative pathogens such as Enterobacteriaceae or Escherichia/Shigella. Greatest stability of the microbiome was determined by higher initial alpha diversity, female sex, high household income and preserved exocrine pancreatic function. Participants who newly developed fatty liver disease or diabetes during the 5-year follow-up already displayed significant microbiota changes at study entry when the diseases were absent. CONCLUSION: This study identifies distinct components of metabolic liver disease to be associated with instability of the intestinal microbiome, increased abundance of facultative pathogens and thus greater susceptibility toward dysbiosis-associated diseases.

10.
Biochim Biophys Acta Mol Cell Res ; : 118914, 2020 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-33245978

RESUMO

The widely conserved twin-arginine translocases (Tat) allow the transport of fully folded cofactor-containing proteins across biological membranes. In doing so, these translocases serve different biological functions ranging from energy conversion to cell division. In the Gram-positive soil bacterium Bacillus subtilis, the Tat machinery is essential for effective growth in media lacking iron or NaCl. It was previously shown that this phenomenon relates to the Tat-dependent export of the heme-containing peroxidase EfeB, which converts Fe2+ to Fe3+ at the expense of hydrogen peroxide. However, the reasons why the majority of tat mutant bacteria perish upon dilution in NaCl-deprived medium and how, after several hours, a sub-population adapts to this condition was unknown. Here we show that, upon growth in the absence of NaCl, the bacteria face two major problems, namely severe oxidative stress at the membrane and starvation leading to death. The tat mutant cells can overcome these challenges if they are fed with arginine, which implies that severe arginine depletion is a major cause of death and resumed arginine synthesis permits their survival. Altogether, our findings show that the Tat system of B. subtilis is needed to preclude severe oxidative stress and starvation upon sudden drops in the environmental Na+ concentration as caused by flooding or rain.

11.
Clin Transl Gastroenterol ; 11(9): e00232, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33094959

RESUMO

INTRODUCTION: Exocrine pancreatic function is a critical host factor in determining the intestinal microbiota composition. Diseases affecting the exocrine pancreas could therefore influence the gut microbiome. We investigated the changes in gut microbiota of patients with chronic pancreatitis (CP). METHODS: Patients with clinical and imaging evidence of CP (n = 51) were prospectively recruited and compared with twice the number of nonpancreatic disease controls matched for distribution in age, sex, body mass index, smoking, diabetes mellitus, and exocrine pancreatic function (stool elastase). From stool samples of these 153 subjects, DNA was extracted, and intestinal microbiota composition was determined by bacterial 16S ribosomal RNA gene sequencing. RESULTS: Patients with CP exhibited severely reduced microbial diversity (Shannon diversity index and Simpson diversity number, P < 0.001) with an increased abundance of facultative pathogenic organisms (P < 0.001) such as Enterococcus (q < 0.001), Streptococcus (q < 0.001), and Escherichia.Shigella (q = 0.002). The CP-associated changes were independent of exocrine pancreatic insufficiency. Short-chain fatty acid producers, considered protective for epithelia such as Faecalibacterium (q < 0.001), showed reduced abundance in patients with CP. Of 4 additional patients with CP previously treated with antibiotics (ceftriaxone and metronidazole), 3 patients were characterized by distinct Enterococcus overgrowth. DISCUSSION: CP is associated with marked gut microbiota dysbiosis, greatly reduced diversity, and increased abundance of opportunistic pathogens, specifically those previously isolated from infected pancreatic necrosis. Taxa with a potentially beneficial role in intestinal barrier function are depleted. These changes can increase the probability of complications from pancreatitis such as infected fluid collections or small intestinal bacterial overgrowth (see Graphical Abstract, Supplementary Digital Content 1, http://links.lww.com/CTG/A383).

12.
Bone ; 141: 115675, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33031973

RESUMO

OBJECTIVE: YKL-40, also known as chitinase-3-like protein 1, is a new proinflammatory biomarker, that might play a role in tissue remodeling and bone resorption. Here we evaluated the associations of the YKL-40 plasma concentration with heel ultrasound parameters and bone turnover markers (BTMs) in adult men and women from the general population. We tested for a causal role of YKL-40 on bone metabolism using published single nucleotide polymorphisms (SNPs) with consequences for YKL-40 expression and function. METHODS: Data were obtained from two population-based cohorts: the Study of Health in Pomerania (SHIP) and SHIP-Trend. Quantitative ultrasound (QUS) measurements at the heel were performed and bone turnover was assessed by measurement of intact amino-terminal propeptide of type I procollagen (PINP) and carboxy-terminal telopeptide of type I collagen (CTX). Associations between the YKL-40 plasma concentration and the QUS-based parameters, bone turnover marker (BTM) concentrations and 44 SNPs, including the lead SNP rs4950928, were evaluated in 382 subjects. Furthermore, we assessed the associations between the same SNPs and the QUS-based parameters (n = 5777) or the BTM concentrations (n = 7190). RESULTS: Sex-specific linear regression models adjusted for a comprehensive panel of interfering covariantes revealed statistically significant inverse associations between YKL-40 and all QUS-based parameters as well as positive associations with CTX in women. The rs4950928 polymorphism was associated with YKL-40 in men and women but none of the tested SNPs was associated with the QUS-based parameters or the BTMs after correction for multiple testing. CONCLUSIONS: Plasma YKL-40 concentrations are associated with QUS-based parameters as well as CTX concentrations in women but these associations are probably not causal.

13.
Artigo em Inglês | MEDLINE | ID: mdl-33013684

RESUMO

Bone production, maintenance, and modeling are a well-balanced process involving mineralization by osteoblasts and resorption by osteoclasts. Sex steroid hormones, including their conjugated forms, contribute majorly to maintaining this balance. Recently, variants in the SLC22A9 gene have been associated with osteoporosis in Korean females. We had recently shown that SLC22A9, encoding organic anion transporter 7 (OAT7), is an uptake transporter of estrone sulfate and identified several genetic variants in Europeans leading to functional consequences in vitro. We therefore hypothesized that SLC22A9 genetic variants may contribute to the pathophysiology of osteoporosis in Europeans. To test this hypothesis, we examined the associations of SLC22A9 variants with bone quality, fractures, and bone turnover markers. We genotyped SLC22A9 variants in 5,701 (2,930 female) subjects (age range, 20-93 years) extracted from the population-based Study of Health in Pomerania (SHIP and SHIP-TREND) covered by the Illumina Infinium HumanExome BeadChip version v1.0 (Exome Chip). Descriptive data (e.g., history of fractures), ultrasonography of the calcaneus, as well as serum concentrations of carboxy-terminal telopeptide of type I collagen, amino-terminal propeptide of type I procollagen, and vitamin D were determined. Comprehensive statistical analyses revealed no association between low-frequency and rare SLC22A9 variants and bone quality, fractures, and bone turnover markers. Our results indicate that single genetic SLC22A9 variants do not have a major impact on osteoporosis risk prediction in Europeans, yet findings need to be replicated in larger-scale studies.

14.
Virulence ; 11(1): 1310-1328, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33017224

RESUMO

Nasopharyngeal colonization by Streptococcus pneumoniae is a prerequisite for pneumococcal transmission and disease. Current vaccines protect only against disease and colonization caused by a limited number of serotypes, consequently allowing serotype replacement and transmission. Therefore, the development of a broadly protective vaccine against colonization, transmission and disease is desired but requires a better understanding of pneumococcal adaptation to its natural niche. Hence, we measured the levels of free and protein-bound transition metals in human nasal fluid, to determine the effect of metal concentrations on the growth and proteome of S. pneumoniae. Pneumococci cultured in medium containing metal levels comparable to nasal fluid showed a highly distinct proteomic profile compared to standard culture conditions, including the increased abundance of nine conserved, putative surface-exposed proteins. AliA, an oligopeptide binding protein, was identified as the strongest protective antigen, demonstrated by the significantly reduced bacterial load in a murine colonization and a lethal mouse pneumonia model, highlighting its potential as vaccine antigen.

15.
Hepatology ; 2020 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-32893372

RESUMO

BACKGROUND & AIMS: Gallbladder cancer (GBC) is a neglected disease with substantial geographical variability: Chile shows the highest incidence worldwide, while GBC is relatively rare in Europe. Here we investigate the causal effects of risk factors considered in current GBC prevention programmes as well as C-reactive protein (CRP) level as a marker of chronic inflammation. APPROACH & RESULTS: We applied two-sample Mendelian randomization (MR) using publicly available data and our own data from a retrospective Chilean and a prospective European study. Causality was assessed by inverse variance weighted (IVW), MR-Egger regression and weighted median estimates complemented with sensitivity analyses on potential heterogeneity and pleiotropy, two-step MR and mediation analysis. We found evidence for a causal effect of gallstone disease on GBC risk in Chileans (p = 9 × 10-5 ) and Europeans (p = 9 × 10-5 ). A genetically elevated body mass index (BMI) increased GBC risk in Chileans (p = 0.03), while higher CRP concentrations increased GBC risk in Europeans (p = 4.1 × 10-6 ). European results suggest causal effects of BMI on gallstone disease (p = 0.008); public Chilean data were not, however, available to enable assessment of the mediation effects among causal GBC risk factors. CONCLUSIONS: Two risk factors considered in the current Chilean programme for GBC prevention are causally linked to GBC risk: gallstones and BMI. For Europeans, BMI showed a causal effect on gallstone risk, which was itself causally linked to GBC risk.

16.
Nutrients ; 12(9)2020 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-32911625

RESUMO

Human donor milk (HDM) provides appropriate nutrition and offers protective functions in preterm infants. The aim of the study is to examine the impact of different storage conditions on the stability of the human breast milk peptidome. HDM was directly frozen at -80 °C or stored at -20 °C (120 h), 4 °C (6 h), or room temperature (RT for 6 or 24 h). The milk peptidome was profiled by mass spectrometry after peptide collection by ultrafiltration. Profiling of the peptidome covered 3587 peptides corresponding to 212 proteins. The variance of the peptidome increased with storage temperature and time and varied for different peptides. The highest impact was observed when samples were stored at RT. Smaller but significant effects were still observed in samples stored at 4 °C, while samples showed highest similarity to those immediately frozen at -80 °C when stored at -20 °C. Peptide structures after storage at RT for 24 h point to the increased activity of thrombin and other proteases cleaving proteins at lysine/arginine. The results point to an ongoing protein degradation/peptide production by milk-derived proteases. They underline the need for immediate freezing of HDM at -20 °C or -80 °C to prevent degradation of peptides and enable reproducible investigation of prospectively collected samples.

17.
Mol Cell Pediatr ; 7(1): 10, 2020 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-32844334

RESUMO

BACKGROUND: Hyperoxia is a well-known cause of cerebral white matter injury in preterm infants with male sex being an independent and critical risk factor for poor neurodevelopmental outcome. Sex is therefore being widely considered as one of the major decisive factors for prognosis and treatment of these infants. But unfortunately, we still lack a clear view of the molecular mechanisms that lead to such a profound difference. Hence, using mouse-derived primary oligodendrocyte progenitor cells (OPCs), we investigated the molecular factors and underlying mechanisms behind the differential response of male and female cells towards oxidative stress. RESULTS: We demonstrate that oxidative stress severely affects cellular functions related to energy metabolism, stress response, and maturation in the male-derived OPCs, whereas the female cells remain largely unaffected. CNPase protein level was found to decline following hyperoxia in male but not in female cells. This impairment of maturation was accompanied by the downregulation of nucleoporin and nuclear lamina proteins in the male cells. We identify Nup133 as a novel target protein affected by hyperoxia, whose inverse regulation may mediate this differential response in the male and female cells. Nup133 protein level declined following hyperoxia in male but not in female cells. We show that nuclear respiratory factor 1 (Nrf1) is a direct downstream target of Nup133 and that Nrf1 mRNA declines following hyperoxia in male but not in female cells. The female cells may be rendered resistant due to synergistic protection via the estrogen receptor alpha (ERα) which was upregulated following hyperoxia in female but not in male cells. Both Nup133 and ERα regulate mitochondrial function and oxidative stress response by transcriptional regulation of Nrf1. CONCLUSIONS: These findings from a basic cell culture model establish prominent sex-based differences and suggest a novel mechanism involved in the differential response of OPCs towards oxidative stress. It conveys a strong message supporting the need to study how complex cellular processes are regulated differently in male and female brains during development and for a better understanding of how the brain copes up with different forms of stress after preterm birth.

18.
Circ Genom Precis Med ; 13(5): 387-395, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32822252

RESUMO

BACKGROUND: The P-wave duration (PWD) is an electrocardiographic measurement that represents cardiac conduction in the atria. Shortened or prolonged PWD is associated with atrial fibrillation (AF). We used exome-chip data to examine the associations between common and rare variants with PWD. METHODS: Fifteen studies comprising 64 440 individuals (56 943 European, 5681 African, 1186 Hispanic, 630 Asian) and ≈230 000 variants were used to examine associations with maximum PWD across the 12-lead ECG. Meta-analyses summarized association results for common variants; gene-based burden and sequence kernel association tests examined low-frequency variant-PWD associations. Additionally, we examined the associations between PWD loci and AF using previous AF genome-wide association studies. RESULTS: We identified 21 common and low-frequency genetic loci (14 novel) associated with maximum PWD, including several AF loci (TTN, CAND2, SCN10A, PITX2, CAV1, SYNPO2L, SOX5, TBX5, MYH6, RPL3L). The top variants at known sarcomere genes (TTN, MYH6) were associated with longer PWD and increased AF risk. However, top variants at other loci (eg, PITX2 and SCN10A) were associated with longer PWD but lower AF risk. CONCLUSIONS: Our results highlight multiple novel genetic loci associated with PWD, and underscore the shared mechanisms of atrial conduction and AF. Prolonged PWD may be an endophenotype for several different genetic mechanisms of AF.

19.
Front Microbiol ; 11: 900, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32477307

RESUMO

Regulated ATP-dependent proteolysis is a common feature of developmental processes and plays also a crucial role during environmental perturbations such as stress and starvation. The Bacillus subtilis MgsR regulator controls a subregulon within the stress- and stationary phase σB regulon. After ethanol exposition and a short time-window of activity, MgsR is ClpXP-dependently degraded with a half-life of approximately 6 min. Surprisingly, a protein interaction analysis with MgsR revealed an association with the McsB arginine kinase and an in vivo degradation assay confirmed a strong impact of McsB on MgsR degradation. In vitro phosphorylation experiments with arginine (R) by lysine (K) substitutions in McsB and its activator McsA unraveled all R residues, which are essentially needed for the arginine kinase reaction. Subsequently, site directed mutagenesis of the MgsR substrate was used to substitute all arginine residues with glutamate (R-E) to mimic arginine phosphorylation and to test their influence on MgsR degradation in vivo. It turned out, that especially the R33E and R94/95E residues (RRPI motif), the latter are adjacently located to the two redox-sensitive cysteines in a 3D model, have the potential to accelerate MgsR degradation. These results imply that selective arginine phosphorylation may have favorable effects for Clp dependent degradation of short-living regulatory proteins. We speculate that in addition to its kinase activity and adaptor function for the ClpC ATPase, McsB might also serve as a proteolytic adaptor for the ClpX ATPase in the degradation mechanism of MgsR.

20.
Exp Clin Endocrinol Diabetes ; 128(6-07): 479-487, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32544978

RESUMO

Determination of the levels of thyroid-stimulating hormone (TSH) and free thyroid hormones (fTHs) is crucial for assessing thyroid function. However, as a result of inter-individual genetic variability and different environmental factors individual set points exist for TSH and fTHs and display considerable variation. Furthermore, under specific pathophysiological conditions like central hypothyroidism, TSH secreting pituitary tumors, or thyroid hormone resistance the established markers TSH and fTH fail to reliably predict thyroid function and adequate supply of TH to peripheral organs. Even in case of overt hyper- and hypothyroidism circulating fTH concentrations do not correlate with clinical symptoms. Therefore, there is a clear need for novel, more specific biomarkers to diagnose and monitor thyroid function. OMICs screening approaches allow parallel profiling of hundreds to thousands of molecules and thus comprehensive monitoring of molecular alterations in tissues and body fluids that might be associated with changes in thyroid function. These techniques thus constitute promising tools for the identification of urgently needed novel biomarkers. This mini review summarizes the findings of OMICs studies in thyroid research with a particular focus on population-based and patient studies as well as interventional approaches investigating the effects of thyroid hormone administration.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA