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Background and 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 programs as well as C‐reactive protein (CRP) level as a marker of chronic inflammation.
Approach and 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 program 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.
Fibroblasts contribute to approximately 20% of the non-cardiomyocytic cells in the heart. They play important roles in the myocardial adaption to stretch, inflammation, and other pathophysiological conditions. Fibroblasts are a major source of extracellular matrix (ECM) proteins whose production is regulated by cytokines, such as TNF-α or TGF-β. The resulting myocardial fibrosis is a hallmark of pathological remodeling in dilated cardiomyopathy (DCM). Therefore, in the present study, the secretome and corresponding transcriptome of human cardiac fibroblasts from patients with DCM was investigated under normal conditions and after TNF-α or TGF-β stimulation. Secreted proteins were quantified via mass spectrometry and expression of genes coding for secreted proteins was analyzed via Affymetrix Transcriptome Profiling. Thus, we provide comprehensive proteome and transcriptome data on the human cardiac fibroblast’s secretome. In the secretome of quiescent fibroblasts, 58% of the protein amount belonged to the ECM fraction. Interestingly, cytokines were responsible for 5% of the total protein amount in the secretome and up to 10% in the corresponding transcriptome. Furthermore, cytokine gene expression and secretion were upregulated upon TNF-α stimulation, while collagen secretion levels were elevated after TGF-β treatment. These results suggest that myocardial fibroblasts contribute to pro-fibrotic and to inflammatory processes in response to extracellular stimuli.
Background: Tissue-resident macrophages have mixed developmental origins. They derive in variable extent from yolk sac (YS) hematopoiesis during embryonic development. Bone marrow (BM) hematopoietic progenitors give rise to tissue macrophages in postnatal life, and their contribution increases upon organ injury. Since the phenotype and functions of macrophages are modulated by the tissue of residence, the impact of their origin and developmental paths has remained incompletely understood. Methods: In order to decipher cell-intrinsic macrophage programs, we immortalized hematopoietic progenitors from YS and BM using conditional HoxB8, and carried out an in-depth functional and molecular analysis of differentiated macrophages. Results: While YS and BM macrophages demonstrate close similarities in terms of cellular growth, differentiation, cell death susceptibility and phagocytic properties, they display differences in cell metabolism, expression of inflammatory markers and inflammasome activation. Reduced abundance of PYCARD (ASC) and CASPASE-1 proteins in YS macrophages abrogated interleukin-1β production in response to canonical and non-canonical inflammasome activation. Conclusions: Macrophage ontogeny is associated with distinct cellular programs and immune response. Our findings contribute to the understanding of the regulation and programming of macrophage functions.
With more than 25 million people affected, heart failure (HF) is a global threat. As energy
production pathways are known to play a pivotal role in HF, we sought here to identify key metabolic
changes in ischemic- and non-ischemic HF by using a multi-OMICS approach. Serum metabolites and
mRNAseq and epigenetic DNA methylation profiles were analyzed from blood and left ventricular
heart biopsy specimens of the same individuals. In total we collected serum from n = 82 patients
with Dilated Cardiomyopathy (DCM) and n = 51 controls in the screening stage. We identified
several metabolites involved in glycolysis and citric acid cycle to be elevated up to 5.7-fold in DCM
(p = 1.7 × 10−6
). Interestingly, cardiac mRNA and epigenetic changes of genes encoding rate-limiting
enzymes of these pathways could also be found and validated in our second stage of metabolite
assessment in n = 52 DCM, n = 39 ischemic HF and n = 57 controls. In conclusion, we identified a
new set of metabolomic biomarkers for HF. We were able to identify underlying biological cascades
that potentially represent suitable intervention targets.
The Study of Health in Pomerania (SHIP), a population-based study from a rural state in northeastern Germany with a relatively poor life expectancy, supplemented its comprehensive examination program in 2008 with whole-body MR imaging at 1.5 T (SHIP-MR). We reviewed more than 100 publications that used the SHIP-MR data and analyzed which sequences already produced fruitful scientific outputs and which manuscripts have been referenced frequently. Upon reviewing the publications about imaging sequences, those that used T1-weighted structured imaging of the brain and a gradient-echo sequence for R2* mapping obtained the highest scientific output; regarding specific body parts examined, most scientific publications focused on MR sequences involving the brain and the (upper) abdomen. We conclude that population-based MR imaging in cohort studies should define more precise goals when allocating imaging time. In addition, quality control measures might include recording the number and impact of published work, preferably on a bi-annual basis and starting 2 years after initiation of the study. Structured teaching courses may enhance the desired output in areas that appear underrepresented.
Our goal was to provide a comprehensive overview of the antibody response to Staphylococcus aureus antigens in the general population as a basis for defining disease-specific profiles and diagnostic signatures. We tested the specific IgG and IgA responses to 79 staphylococcal antigens in 996 individuals from the population-based Study of Health in Pomerania. Using a dilution-based multiplex suspension array, we extended the dynamic range of specific antibody detection to seven orders of magnitude, allowing the precise quantification of high and low abundant antibody specificities in the same sample. The observed IgG and IgA antibody responses were highly heterogeneous with differences between individuals as well as between bacterial antigens that spanned several orders of magnitude. Some antigens elicited significantly more IgG than IgA and vice versa. We confirmed a strong influence of colonization on the antibody response and quantified the influence of sex, smoking, age, body mass index, and serum glucose on anti-staphylococcal IgG and IgA. However, all host parameters tested explain only a small part of the extensive variability in individual response to the different antigens of S. aureus.
Extracellular vesicles (EVs) are reminiscent of their cell of origin and thus represent a
valuable source of biomarkers. However, for EVs to be used as biomarkers in clinical practice, simple,
comparable, and reproducible analytical methods must be applied. Although progress is being
made in EV separation methods for human biofluids, the implementation of EV assays for clinical
diagnosis and common guidelines are still lacking. We conducted a comprehensive analysis of
established EV separation techniques from human serum and plasma, including ultracentrifugation
and size exclusion chromatography (SEC), followed by concentration using (a) ultracentrifugation,
(b) ultrafiltration, or (c) precipitation, and immunoaffinity isolation. We analyzed the size, number,
protein, and miRNA content of the obtained EVs and assessed the functional delivery of EV cargo.
Our results demonstrate that all methods led to an adequate yield of small EVs. While no significant
difference in miRNA content was observed for the different separation methods, ultracentrifugation
was best for subsequent flow cytometry analysis. Immunoaffinity isolation is not suitable for
subsequent protein analyses. SEC + ultracentrifugation showed the best functional delivery of
EV cargo. In summary, combining SEC with ultracentrifugation gives the highest yield of pure
and functional EVs and allows reliable analysis of both protein and miRNA contents. We propose
this combination as the preferred EV isolation method for biomarker studies from human serum
or plasma.
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.