Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disorder in industrialized countries. Liver samples from morbidly obese patients (n = 45) with all stages of NAFLD and ...controls (n = 18) were analyzed by array-based DNA methylation and mRNA expression profiling. NAFLD-specific expression and methylation differences were seen for nine genes coding for key enzymes in intermediate metabolism (including PC, ACLY, and PLCG1) and insulin/insulin-like signaling (including IGF1, IGFBP2, and PRKCE) and replicated by bisulfite pyrosequening (independent n = 39). Transcription factor binding sites at NAFLD-specific CpG sites were >1,000-fold enriched for ZNF274, PGC1A, and SREBP2. Intraindividual comparison of liver biopsies before and after bariatric surgery showed NAFLD-associated methylation changes to be partially reversible. Postbariatric and NAFLD-specific methylation signatures were clearly distinct both in gene ontology and transcription factor binding site analyses, with >400-fold enrichment of NRF1, HSF1, and ESRRA sites. Our findings provide an example of treatment-induced epigenetic organ remodeling in humans.
•Nonalcoholic fatty liver disease has a specific methylation signature•Consistent expression and methylation may point to epigenetic drivers of disease•The epigenetic signature after bariatric surgery is distinct from disease patterns•ENCODE analysis points to candidate transcription factors for liver remodeling
Obesity accelerates epigenetic aging of human liver Horvath, Steve; Erhart, Wiebke; Brosch, Mario ...
Proceedings of the National Academy of Sciences - PNAS,
10/2014, Letnik:
111, Številka:
43
Journal Article
Recenzirano
Odprti dostop
Significance Because obese people are at an increased risk of many age-related diseases, it is a plausible hypothesis that obesity increases the biological age of some tissues and cell types. ...However, it has been difficult to detect such an accelerated aging effect because it is unclear how to measure tissue age. Here we use a recently developed biomarker of aging (known as “epigenetic clock”) to study the relationship between epigenetic age and obesity in several human tissues. We report an unexpectedly strong correlation between high body mass index and the epigenetic age of liver tissue. This finding may explain why obese people suffer from the early onset of many age-related pathologies, including liver cancer.
Because of the dearth of biomarkers of aging, it has been difficult to test the hypothesis that obesity increases tissue age. Here we use a novel epigenetic biomarker of aging (referred to as an “epigenetic clock”) to study the relationship between high body mass index (BMI) and the DNA methylation ages of human blood, liver, muscle, and adipose tissue. A significant correlation between BMI and epigenetic age acceleration could only be observed for liver ( r = 0.42, P = 6.8 × 10 ⁻⁴ in dataset 1 and r = 0.42, P = 1.2 × 10 ⁻⁴ in dataset 2). On average, epigenetic age increased by 3.3 y for each 10 BMI units. The detected age acceleration in liver is not associated with the Nonalcoholic Fatty Liver Disease Activity Score or any of its component traits after adjustment for BMI. The 279 genes that are underexpressed in older liver samples are highly enriched (1.2 × 10 ⁻⁹) with nuclear mitochondrial genes that play a role in oxidative phosphorylation and electron transport. The epigenetic age acceleration, which is not reversible in the short term after rapid weight loss induced by bariatric surgery, may play a role in liver-related comorbidities of obesity, such as insulin resistance and liver cancer.
Toll-like receptors (TLR) are overexpressed on many types of cancer cells, including colorectal cancer cells, but little is known about the functional relevance of these immune regulatory molecules ...in malignant settings. Here, we report frequent single-nucleotide polymorphisms (SNP) in the flagellin receptor TLR5 and the TLR downstream effector molecules MyD88 and TIRAP that are associated with altered survival in a large cohort of Caucasian patients with colorectal cancer (n = 613). MYD88 rs4988453, a SNP that maps to a promoter region shared with the acetyl coenzyme-A acyl-transferase-1 (ACAA1), was associated with decreased survival of patients with colorectal cancer and altered transcriptional activity of the proximal genes. In the TLR5 gene, rs5744174/F616L was associated with increased survival, whereas rs2072493/N592S was associated with decreased survival. Both rs2072493/N592S and rs5744174/F616L modulated TLR5 signaling in response to flagellin or to different commensal and pathogenic intestinal bacteria. Notably, we observed a reduction in flagellin-induced p38 phosphorylation, CD62L shedding, and elevated expression of interleukin (IL)-6 and IL-1β mRNA in human primary immune cells from TLR5 616LL homozygote carriers, as compared with 616FF carriers. This finding suggested that the well-documented effect of cytokines like IL-6 on colorectal cancer progression might be mediated by TLR5 genotype-dependent flagellin sensing. Our results establish an important link between TLR signaling and human colorectal cancer with relevance for biomarker and therapy development.
Background & Aims Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disorder in industrialized countries. Mouse models of NAFLD have been used in studies of pathogenesis and ...treatment, and have certain features of the human disease. We performed a systematic transcriptome-wide analysis of liver tissues from patients at different stages of NAFLD progression (ranging from healthy obese individuals to those with steatosis), as well as rodent models of NAFLD, to identify those that most closely resemble human disease progression in terms of gene expression patterns. Methods We performed a systematic evaluation of genome-wide messenger RNA expression using liver tissues collected from mice fed a standard chow diet (controls) and 9 mouse models of NAFLD: mice on a high-fat diet (with or without fructose), mice on a Western-type diet, mice on a methionine- and choline-deficient diet, mice on a high-fat diet given streptozotocin, and mice with disruption of Pten in hepatocytes. We compared gene expression patterns with those of liver tissues from 25 patients with nonalcoholic steatohepatitis (NASH), 27 patients with NAFLD, 15 healthy obese individuals, and 39 healthy nonobese individuals (controls). Liver samples were obtained from patients undergoing liver biopsy for suspected NAFLD or NASH, or during liver or bariatric surgeries. Data sets were analyzed using the limma R-package. Overlap of functional profiles was analyzed by gene set enrichment analysis profiles. Results We found differences between human and mouse transcriptomes to be significantly larger than differences between disease stages or models. Of the 65 genes with significantly altered expression in patients with NASH and 177 genes with significantly altered expression in patients with NAFLD, compared with controls, only 1–18 of these genes also differed significantly in expression between mouse models of NAFLD and control mice. However, expression of genes that regulate pathways associated with the development of NAFLD were altered in some mouse models (such as pathways associated with lipid metabolism). On a pathway level, gene expression patterns in livers of mice on the high-fat diet were associated more closely with human fatty liver disease than other models. Conclusions In comparing gene expression profiles between liver tissues from different mouse models of NAFLD and patients with different stages of NAFLD, we found very little overlap. Our data set is available for studies of pathways that contribute to the development of NASH and NAFLD and selection of the most applicable mouse models ( http://www.nash-profiler.com ).
Solid tumors are characterized by global metabolic alterations which contribute to their growth and progression. Altered gene expression profiles and plasma lipid composition suggested a role for ...metabolic reprogramming in colorectal cancer (CRC) development. However, a conclusive picture of CRC-associated lipidome alterations in the tumor tissue has not emerged. Here, we determined molar abundances of 342 species from 20 lipid classes in matched biopsies of CRC and adjacent normal mucosa. We demonstrate that in contrast to previous reports, CRC shows a largely preserved lipidome composition that resembles that of normal colonic mucosa. Important exceptions include increased levels of lyso-phosphatidylinositols in CRC and reduced abundance of ether phospholipids in advanced stages of CRC. As such, our observations challenge the concept of widespread alterations in lipid metabolism in CRC and rather suggest changes in the cellular lipid profile that are limited to selected lipids involved in signaling and the scavenging of reactive oxygen species.
•We provide comprehensive, quantitative lipidomics of colorectal cancer (CRC) tissue.•The lipidome of CRC largely resembles that of normal mucosa.•Changes in lipid abundance are limited to few lyso-phospholipids and ether lipids.•Our results do not support the notion of global lipidome alterations in CRC.
A deeper epigenomic understanding of spatial organization of cells in human tissues is an important challenge. Here we report the first combined positional analysis of transcriptomes and methylomes ...across three micro-dissected zones (pericentral, intermediate and periportal) of human liver. We identify pronounced anti-correlated transcriptional and methylation gradients including a core of 271 genes controlling zonated metabolic and morphogen networks and observe a prominent porto-central gradient of DNA methylation at binding sites of 46 transcription factors. The gradient includes an epigenetic and transcriptional Wnt signature supporting the concept of a pericentral hepatocyte regeneration pathway under steady-state conditions. While donors with non-alcoholic fatty liver disease show consistent gene expression differences corresponding to the severity of the disease across all zones, the relative zonated gene expression and DNA methylation patterns remain unchanged. Overall our data provide a wealth of new positional insights into zonal networks controlled by epigenetic and transcriptional gradients in human liver.
Obesity and type 2 diabetes (T2D) show an increased risk for a severe COVID-19 disease. Treatment with DPP4 inhibitor (DPP4i) results in reduced mortality and better clinical outcome. Here, we aimed ...to identify potential mechanisms for the observed DPP4i effect in COVID-19. Comparing T2D subjects with and without DPP4i treatment, we identified a significant increase of the anti-inflammatory adipokine sFRP5 in relation to DPP4 inhibition. sFRP5 is a specific antagonist to Wnt5a, a glycopeptide secreted by adipose tissue macrophages acting pro-inflammatory in various diseases. We therefore examined sFRP5 levels in patients hospitalised for severe COVID-19 and found significant lower levels compared to healthy controls. Since sFRP5 might consequently be a molecular link for the beneficial effects of DPP4i in COVID-19, we further aimed to identify the exact source of sFRP5 in adipose tissue on cellular level. We therefore isolated pre-adipocytes, mature adipocytes and macrophages from adipose tissue biopsies and performed western-blotting. Results showed a sFRP5 expression specifically in mature adipocytes of subcutaneous and omental adipose tissue. In summary, our data suggest that DPP4i increase serum levels of anti-inflammatory sFRP5 which might be beneficial in COVID-19, reflecting a state of sFRP5 deficiency.
Introduction: Revisional procedures in bariatric surgery are regarded as technically more demanding and riskier than primary interventions. While the use of the surgical robot has not yet proven to ...be advantageous in primary bariatric interventions, the question remains whether its use is justified for more complex revisional procedures. Objective: To show that revisional bariatric surgery can be performed safely using the da Vinci® Xi surgical system. Methods: We performed a retrospective analysis of prospectively recorded data for revisional bariatric procedures between January 2016 and November 2019. Results: Of 78 revision operations, four (5.1%) were performed by open surgery, 30 (38.5%) by laparoscopic surgery, and 44 (56.4%) by robotic surgery. A comparative analysis of robotic (n = 41) versus laparoscopic (n = 18) revisional Roux-en-Y gastric bypasses (rRYGB) revealed significant differences favoring the robotic approach for operative time (130.7 vs. 167.6 min), C-reactive protein values at days 1 (27.9 vs. 49.1 mg/L) and 2 (48.2 vs. 83.6 mg/L) after surgery, and length of stay (4.9 vs. 6.2 days). Lower complication rates (Clavien-Dindo II–V) were found after rRRYGB (7.3 vs. 22.2%, not significant). Conclusions: Revisional bariatric surgery using a robotic system is safe. The operative time performing rRRYGB is significantly shorter than rLRYGB in our experience. Otherwise, results were largely comparable. Due to different indications, different index operations and a wide range of revisional procedures, further studies are necessary to confirm these results.
Background
Non‐alcoholic fatty liver disease (NAFLD) is the most common chronic liver disorder in industrialized countries, yet its pathophysiology is incompletely understood. Small‐molecule ...metabolite screens may offer new insights into disease mechanisms and reveal new treatment targets.
Methods
Discovery (N = 33) and replication (N = 66) of liver biopsies spanning the range from normal liver histology to non‐alcoholic steatohepatitis (NASH) were ascertained ensuring rapid freezing under 30 s in patients. 252 metabolites were assessed using GC/MS. Replicated metabolites were evaluated in a murine high‐fat diet model of NAFLD.
Results
In a two‐stage metabolic screening, hydroquinone (HQ, pcombined = 3.0 × 10−4) and nicotinic acid (NA, pcombined = 3.9 × 10−9) were inversely correlated with histological NAFLD severity. A murine high‐fat diet model of NAFLD demonstrated a protective effect of these two substances against NAFLD: Supplementation with 1% HQ reduced only liver steatosis, whereas 0.6% NA reduced both liver fat content and serum transaminase levels and induced a complex regulatory network of genes linked to NALFD pathogenesis in a global expression pathway analysis. Human nutritional intake of NA equivalent was also consistent with a protective effect of NA against NASH progression.
Conclusion
This first small‐molecular screen of human liver tissue identified two replicated protective metabolites. Either the use of NA or targeting its regulatory pathways might be explored to treat or prevent human NAFLD.
PDF
