Obesity has a major socio-economic health impact. There are profound sex differences in adipose tissue deposition and obesity-related conditions. The underlying mechanisms driving sexual dimorphism in obesity and its associated metabolic disorders remain unclear. Histone variant macroH2A1.1 is a candidate epigenetic mechanism linking environmental and dietary factors to obesity. Here, we used a mouse model genetically depleted of macroH2A1.1 to investigate its potential epigenetic role in sex dimorphic obesity, metabolic disturbances and gut dysbiosis. Whole body macroH2A1 knockout (KO) mice, generated with the Cre/loxP technology, and their control littermates were fed a high fat diet containing 60% of energy derived from fat. The diet was administered for three months starting from 10 to 12 weeks of age. We evaluated the progression in body weight, the food intake, and the tolerance to glucose by means of a glucose tolerance test. Gut microbiota composition, visceral adipose and liver tissue morphology were assessed. In addition, adipogenic gene expression patterns were evaluated in the visceral adipose tissue. Female KO mice for macroH2A1.1 had a more pronounced weight gain induced by high fat diet compared to their littermates, while the increase in body weight in male mice was similar in the two genotypes. Food intake was generally increased upon KO and decreased by high fat diet in both sexes, with the exception of KO females fed a high fat diet that displayed the same food intake of their littermates. In glucose tolerance tests, glucose levels were significantly elevated upon high fat diet in female KO compared to a standard diet, while this effect was absent in male KO. There were no differences in hepatic histology. Upon a high fat diet, in female adipocyte cross-sectional area was larger in KO compared to littermates: activation of proadipogenic genes (ACACB, AGT, ANGPT2, FASN, RETN, SLC2A4) and downregulation of antiadipogenic genes (AXIN1, E2F1, EGR2, JUN, SIRT1, SIRT2, UCP1, CCND1, CDKN1A, CDKN1B, EGR2) was detected. Gut microbiota profiling showed increase in Firmicutes and a decrease in Bacteroidetes in females, but not males, macroH2A1.1 KO mice. MacroH2A1.1 KO mice display sexual dimorphism in high fat diet-induced obesity and in gut dysbiosis, and may represent a useful model to investigate epigenetic and metabolic differences associated to the development of obesity-associated pathological conditions in males and females.

• MeSH
• dieta s vysokým obsahem tuků škodlivé účinky   MeSH
• dysbióza * MeSH
• glukosa metabolismus   MeSH
• histony * genetika   metabolismus   MeSH
• myši inbrední C57BL MeSH
• myši knockoutované MeSH
• myši MeSH
• obezita genetika   metabolismus   MeSH
• tělesná hmotnost MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• glukosa MeSH
• histony * MeSH
• Macroh2a1 protein, mouse MeSH Prohlížeč

DNA damage repair (DDR) is a safeguard for genome integrity maintenance. Increasing DDR efficiency could increase the yield of induced pluripotent stem cells (iPSC) upon reprogramming from somatic cells. The epigenetic mechanisms governing DDR during iPSC reprogramming are not completely understood. Our goal was to evaluate the splicing isoforms of histone variant macroH2A1, macroH2A1.1, and macroH2A1.2, as potential regulators of DDR during iPSC reprogramming. GFP-Trap one-step isolation of mtagGFP-macroH2A1.1 or mtagGFP-macroH2A1.2 fusion proteins from overexpressing human cell lines, followed by liquid chromatography-tandem mass spectrometry analysis, uncovered macroH2A1.1 exclusive interaction with Poly-ADP Ribose Polymerase 1 (PARP1) and X-ray cross-complementing protein 1 (XRCC1). MacroH2A1.1 overexpression in U2OS-GFP reporter cells enhanced specifically nonhomologous end joining (NHEJ) repair pathway, while macroH2A1.1 knock-out (KO) mice showed an impaired DDR capacity. The exclusive interaction of macroH2A1.1, but not macroH2A1.2, with PARP1/XRCC1, was confirmed in human umbilical vein endothelial cells (HUVEC) undergoing reprogramming into iPSC through episomal vectors. In HUVEC, macroH2A1.1 overexpression activated transcriptional programs that enhanced DDR and reprogramming. Consistently, macroH2A1.1 but not macroH2A1.2 overexpression improved iPSC reprogramming. We propose the macroH2A1 splicing isoform macroH2A1.1 as a promising epigenetic target to improve iPSC genome stability and therapeutic potential.

• Klíčová slova
• DNA damage, cell reprogramming, induced pluripotent stem cells, macroH2A1.1,
• MeSH
• DNA MeSH
• endoteliální buňky metabolismus   MeSH
• histony * metabolismus   MeSH
• indukované pluripotentní kmenové buňky * metabolismus   MeSH
• lidé MeSH
• myši MeSH
• oprava DNA MeSH
• protein XRCC1 genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• DNA MeSH
• histony * MeSH
• MACROH2A1 protein, human MeSH Prohlížeč
• protein XRCC1 MeSH
• XRCC1 protein, human MeSH Prohlížeč

Background: Gene expression in eukaryotic cells can be governed by histone variants, which replace replication-coupled histones, conferring unique chromatin properties. MacroH2A1 is a histone H2A variant containing a domain highly similar to H2A and a large non-histone (macro) domain. MacroH2A1, in turn, is present in two alternatively exon-spliced isoforms: macroH2A1.1 and macroH2A1.2, which regulate cell plasticity and proliferation in a remarkably distinct manner. The N-terminal and the C-terminal tails of H2A histones stem from the nucleosome core structure and can be target sites for several post-translational modifications (PTMs). MacroH2A1.1 and macroH2A1.2 isoforms differ only in a few amino acids and their ability to bind NAD-derived metabolites, a property allegedly conferring their different functions in vivo. Some of the modifications on the macroH2A1 variant have been identified, such as phosphorylation (T129, S138) and methylation (K18, K123, K239). However, no study to our knowledge has analyzed extensively, and in parallel, the PTM pattern of macroH2A1.1 and macroH2A1.2 in the same experimental setting, which could facilitate the understanding of their distinct biological functions in health and disease. Methods: We used a mass spectrometry-based approach to identify the sites for phosphorylation, acetylation, and methylation in green fluorescent protein (GFP)-tagged macroH2A1.1 and macroH2A1.2 expressed in human hepatoma cells. The impact of selected PTMs on macroH2A1.1 and macroH2A1.2 structure and function are demonstrated using computational analyses. Results: We identified K7 as a new acetylation site in both macroH2A1 isoforms. Quantitative comparison of histone marks between the two isoforms revealed significant differences in the levels of phosphorylated T129 and S170. Our computational analysis provided evidence that the phosphorylation status in the intrinsically disordered linker region in macroH2A1 isoforms might represent a key regulatory element contributing to their distinct biological responses. Conclusions: Taken together, our results report different PTMs on the two macroH2A1 splicing isoforms as responsible for their distinct features and distribution in the cell.

• Klíčová slova
• macroH2A1, mass spectrometry, post-translational modifications,
• Publikační typ
• časopisecké články MeSH

BACKGROUND: Although metabolic associate fatty liver disease (MAFLD) is associated with obesity, it can also occur in lean patients. MAFLD is more aggressive in lean patients compared to obese patients, with a higher risk of mortality. Specific biomarkers to diagnose differentially lean or overweight MAFLD are missing. Histones and nucleosomes are released in the bloodstream upon cell death. Here, we propose a new, fast, imaging and epigenetics based approach to investigate the severity of steatosis in lean MAFLD patients. RESULTS: A total of 53 non-obese patients with histologically confirmed diagnosis of MAFLD were recruited. Twenty patients displayed steatosis grade 1 (0-33%), 24 patients with steatosis grade 2 (34-66%) and 9 patients with steatosis grade 3 (67-100%). The levels of circulating nucleosomes were assayed using enzyme-linked immunosorbent assay, while individual histones or histone dimers were assayed in serum samples by means of a new advanced flow cytometry ImageStream(X)-adapted method. Circulating nucleosome levels associated poorly with MAFLD in the absence of obesity. We implemented successfully a multi-channel flow methodology on ImageStream(X), to image single histone staining (H2A, H2B, H3, H4, macroH2A1.1 and macroH2A1.2). We report here a significant depletion of the levels of histone variants macroH2A1.1 and macroH2A1.2 in the serum of lean MAFLD patients, either individually or in complex with H2B. CONCLUSIONS: In summary, we identified a new circulating histone signature able to discriminate the severity of steatosis in individuals with lean MAFLD, using a rapid and non-invasive ImageStream(X)-based imaging technology.

• Klíčová slova
• Epigenetics, Histones, ImageStream, Lean MAFLD, Liquid biopsy, Metabolic health,
• MeSH
• dospělí MeSH
• histony krev   MeSH
• hubenost krev   MeSH
• lidé středního věku MeSH
• lidé MeSH
• metabolické nemoci krev   komplikace   MeSH
• stupeň závažnosti nemoci MeSH
• ztučnělá játra krev   komplikace   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• histony MeSH

Staining mice tissues for β-galactosidase activity is a fundamental tool to detect age- or disease-associated cellular senescence. However, reported analyses of positivity for senescence-associated β-galactosidase activity or for other markers of senescence in post-mitotic cells of healthy murine tissues have been fragmentary or inconclusive. Here, we attempted to independently deepen this knowledge using multiple senescence markers within the same cells of wild type mice entering middle age (9 months of age). A histochemistry protocol for the pH-dependent detection of β-galactosidase activity in several tissues was used. At pH 6, routinely utilized to detect senescence-associated β-galactosidase activity, only specific cellular populations in the mouse body (including Purkinje cells and choroid plexus in the central nervous system) were detected as strongly positive for β-galactosidase activity. These post-mitotic cells were also positive for other established markers of senescence (p16, p21 and DPP4), detected by immunofluorescence, confirming a potential senescent phenotype. These data might contribute to understanding the functional relation between the senescence-associated β-galactosidase activity and senescence markers in post-mitotic cells in absence of disease or advanced aging.

• Klíčová slova
• markers, mice, senescence,
• MeSH
• beta-galaktosidasa metabolismus   MeSH
• biologické markery metabolismus   MeSH
• imunohistochemie MeSH
• koncentrace vodíkových iontů MeSH
• mitóza fyziologie   MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• stárnutí buněk fyziologie   MeSH
• stárnutí fyziologie   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• beta-galaktosidasa MeSH
• biologické markery MeSH

Uveal melanoma (UM) is the most common primary intraocular tumour in adults. The most accurate prognostic factor of UM is classification by gene expression profiling. Currently, the role of epigenetics is much less defined compared to genetic mechanisms. We recently showed a strong prognostic role of the expression levels of histone variant macroH2A1 in UM patients. Here, we assessed the mechanistic effects of macroH2A1 on UM progression.UM cell lines were stably knocked down (KD) for macroH2A1, and proliferation and colony formation capacity were evaluated. Mitochondrial function was assayed through qPCR and HPLC analyses. Correlation between mitochondrial gene expression and cancer aggressiveness was studied using a bioinformatics approach.MacroH2A1 loss significantly attenuated UM cells proliferation and aggressiveness. Furthermore, genes involved in oxidative phosphorylation displayed a decreased expression in KD cells. Consistently, macroH2A1 loss resulted also in a significant decrease of mitochondrial transcription factor A (TFAM) expression, suggesting impaired mitochondrial replication. Bioinformatics analyses uncovered that the expression of genes involved in mitochondrial metabolism correlates with macroH2A1 and with cancer aggressiveness in UM patients. Altogether, our results suggest that macroH2A1 controls UM cells progression and it may represent a molecular target to develop new pharmacological strategies for UM treatment.

• Klíčová slova
• epigenetics, histones, macroH2A1, metabolism, uveal melanoma,
• MeSH
• DNA vazebné proteiny metabolismus   MeSH
• histony nedostatek   MeSH
• lidé MeSH
• melanocyty metabolismus   MeSH
• melanom genetika   MeSH
• mitochondriální proteiny metabolismus   MeSH
• mitochondrie metabolismus   MeSH
• nádorové buněčné linie MeSH
• nádorové kmenové buňky metabolismus   MeSH
• nádory uvey genetika   MeSH
• proliferace buněk genetika   MeSH
• regulace genové exprese u nádorů genetika   MeSH
• transkripční faktory metabolismus   MeSH
• uveální melanom MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DNA vazebné proteiny MeSH
• histony MeSH
• MACROH2A1 protein, human MeSH Prohlížeč
• mitochondrial transcription factor A MeSH Prohlížeč
• mitochondriální proteiny MeSH
• transkripční faktory MeSH

Rationale: Loss of histone macroH2A1 induces appearance of cancer stem cells (CSCs)-like cells in hepatocellular carcinoma (HCC). How CSCs interact with the tumor microenvironment and the adaptive immune system is unclear. Methods: We screened aggressive human HCC for macroH2A1 and CD44 CSC marker expression. We also knocked down (KD) macroH2A1 in HCC cells, and performed integrated transcriptomic and secretomic analyses. Results: Human HCC showed low macroH2A1 and high CD44 expression compared to control tissues. MacroH2A1 KD CSC-like cells transferred paracrinally their chemoresistant properties to parental HCC cells. MacroH2A1 KD conditioned media transcriptionally reprogrammed parental HCC cells activated regulatory CD4+/CD25+/FoxP3+ T cells (Tregs). Conclusions: Loss of macroH2A1 in HCC cells drives cancer stem-cell propagation and evasion from immune surveillance.

• Klíčová slova
• adaptive immune system, chemoresistance., hepatocellular carcinoma, histone macroH2A1,
• MeSH
• antigeny CD44 metabolismus   MeSH
• chemorezistence * MeSH
• forkhead transkripční faktory metabolismus   MeSH
• genový knockdown MeSH
• glykolýza MeSH
• hepatocelulární karcinom farmakoterapie   imunologie   metabolismus   patologie   MeSH
• histony metabolismus   MeSH
• lidé středního věku MeSH
• lidé MeSH
• metabolomika metody   MeSH
• nádorové buněčné linie MeSH
• nádorové kmenové buňky účinky léků   imunologie   patologie   MeSH
• nádorové mikroprostředí imunologie   MeSH
• nádory jater farmakoterapie   imunologie   metabolismus   patologie   MeSH
• parakrinní signalizace * MeSH
• receptor interleukinu-2 - alfa-podjednotka metabolismus   MeSH
• regulace genové exprese u nádorů MeSH
• regulační T-lymfocyty imunologie   MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antigeny CD44 MeSH
• CD44 protein, human MeSH Prohlížeč
• forkhead transkripční faktory MeSH
• FOXP3 protein, human MeSH Prohlížeč
• histony MeSH
• macroH2A histone MeSH Prohlížeč
• receptor interleukinu-2 - alfa-podjednotka MeSH

The biological clock controls at the molecular level several aspects of mammalian physiology, by regulating daily oscillations of crucial biological processes such as nutrient metabolism in the liver. Disruption of the circadian clock circuitry has recently been identified as an independent risk factor for cancer and classified as a potential group 2A carcinogen to humans. Hepatocellular carcinoma (HCC) is the prevailing histological type of primary liver cancer, one of the most important causes of cancer-related death worldwide. HCC onset and progression is related to B and C viral hepatitis, alcoholic and especially non-alcoholic fatty liver disease (NAFLD)-related milieu of fibrosis, cirrhosis, and chronic inflammation. In this review, we recapitulate the state-of-the-art knowledge on the interplay between the biological clock and the oncogenic pathways and mechanisms involved in hepatocarcinogenesis. Finally, we propose how a deeper understanding of circadian clock circuitry-cancer pathways' crosstalk is promising for developing new strategies for HCC prevention and management.

• Klíčová slova
• chronotherapy, circadian clock, hepatocellular carcinoma (HCC),
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

BACKGROUND: Epigenetic regulation is important in hematopoiesis, but the involvement of histone variants is poorly understood. Myelodysplastic syndromes (MDS) are heterogeneous clonal hematopoietic stem cell (HSC) disorders characterized by ineffective hematopoiesis. MacroH2A1.1 is a histone H2A variant that negatively correlates with the self-renewal capacity of embryonic, adult, and cancer stem cells. MacroH2A1.1 is a target of the frequent U2AF1 S34F mutation in MDS. The role of macroH2A1.1 in hematopoiesis is unclear. RESULTS: MacroH2A1.1 mRNA levels are significantly decreased in patients with low-risk MDS presenting with chromosomal 5q deletion and myeloid cytopenias and tend to be decreased in MDS patients carrying the U2AF1 S34F mutation. Using an innovative mouse allele lacking the macroH2A1.1 alternatively spliced exon, we investigated whether macroH2A1.1 regulates HSC homeostasis and differentiation. The lack of macroH2A1.1 decreased while macroH2A1.1 haploinsufficiency increased HSC frequency upon irradiation. Moreover, bone marrow transplantation experiments showed that both deficiency and haploinsufficiency of macroH2A1.1 resulted in enhanced HSC differentiation along the myeloid lineage. Finally, RNA-sequencing analysis implicated macroH2A1.1-mediated regulation of ribosomal gene expression in HSC homeostasis. CONCLUSIONS: Together, our findings suggest a new epigenetic process contributing to hematopoiesis regulation. By combining clinical data with a discrete mutant mouse model and in vitro studies of human and mouse cells, we identify macroH2A1.1 as a key player in the cellular and molecular features of MDS. These data justify the exploration of macroH2A1.1 and associated proteins as therapeutic targets in hematological malignancies.

• Klíčová slova
• Hematopoiesis, MacroH2A1, Myelodysplastic syndrome,
• MeSH
• buněčná diferenciace MeSH
• chromozomální delece MeSH
• down regulace * MeSH
• epigeneze genetická MeSH
• haploinsuficience MeSH
• hematopoetické kmenové buňky chemie   cytologie   MeSH
• histony genetika   MeSH
• lidé MeSH
• lidské chromozomy, pár 5 genetika   MeSH
• makrocytární anemie genetika   MeSH
• místa sestřihu RNA MeSH
• modely nemocí na zvířatech MeSH
• mutace MeSH
• myelodysplastické syndromy genetika   MeSH
• myši MeSH
• sekvenční analýza RNA MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• histony MeSH
• macroH2A histone MeSH Prohlížeč
• MACROH2A1 protein, human MeSH Prohlížeč
• Macroh2a1 protein, mouse MeSH Prohlížeč
• místa sestřihu RNA MeSH

Gastrointestinal cancers (GC) are malignancies involving the gastrointestinal (GI) tract and accessory organs of the digestive system, including the pancreas, liver, and gall bladder. GC is one of the most common cancers and contributes to more cancer-related deaths than cancers of any other system in the human body. Causative factors of GC have been consistently attributed to infections, smoking, an unhealthy diet, obesity, diabetes, and genetic factors. More recently, aberrant epigenetic regulation of gene expression has emerged as a new, fundamental pathway in GC pathogenesis. In this review, we summarize the role of the macroH2A histone family in GI cell function and malignant transformation, and highlight how this histone family may open up novel biomarkers for cancer detection, prediction, and response to treatment.

• Klíčová slova
• epigenetics, gastrointestinal cancer, histone variants, macroH2A,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH