Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 199
Filter
1.
Diabetologia ; 67(9): 1897-1911, 2024 Sep.
Article in English | MEDLINE | ID: mdl-39245780

ABSTRACT

AIMS/HYPOTHESIS: Apart from its fibrinolytic activity, the tissue plasminogen activator (tPA)/plasmin system has been reported to cleave the peptide amyloid beta, attenuating brain amyloid deposition in Alzheimer's disease. As aggregation of human islet amyloid polypeptide (hIAPP) is toxic to beta cells, we sought to determine whether activation of the fibrinolytic system can also reduce islet amyloid deposition and its cytotoxic effects, which are both observed in type 2 diabetes. METHODS: The expression of Plat (encoding tPA) and plasmin activity were measured in isolated islets from amyloid-prone hIAPP transgenic mice or non-transgenic control islets expressing non-amyloidogenic mouse islet amyloid polypeptide cultured in the absence or presence of the amyloid inhibitor Congo Red. Plat expression was also determined in hIAPP-treated primary islet endothelial cells, bone marrow-derived macrophages (BMDM) and INS-1 cells, in order to determine the islet cell type(s) producing tPA in response to hIAPP aggregation. Cell-free thioflavin-T assays and MS were used to respectively monitor hIAPP aggregation kinetics and investigate plasmin cleavage of hIAPP. Cell viability was assessed in INS-1 beta cells treated with hIAPP with or without plasmin. Finally, to confirm the findings in human samples, PLAT expression was measured in freshly isolated islets from donors with and without type 2 diabetes. RESULTS: In isolated islets from transgenic mice, islet Plat expression and plasmin activity increased significantly with the process of amyloid deposition (p≤0.01, n=5); these effects were not observed in islets from non-transgenic mice and were blocked by Congo Red (p≤0.01, n=4). In response to hIAPP exposure, Plat expression increased in BMDM and INS-1 cells vs vehicle-treated cells (p≤0.05, n=4), but not in islet endothelial cells. Plasmin reduced hIAPP fibril formation in a dose-dependent manner in a cell-free system, and restored hIAPP-induced loss of cell viability in INS-1 beta cells (p≤0.01, n=5). Plasmin cleaved monomeric hIAPP, inducing a rapid decrease in the abundance of full-length hIAPP and the appearance of hIAPP 1-11 and 12-37 fragments. hIAPP 12-37, which contains the critical amyloidogenic region, was not toxic to INS-1 cells. Finally, PLAT expression was significantly increased by 2.4-fold in islets from donors with type 2 diabetes (n=4) vs islets from donors without type 2 diabetes (n=7) (p≤0.05). CONCLUSIONS/INTERPRETATION: The fibrinolytic system is upregulated in islets with hIAPP aggregation. Plasmin rapidly degrades hIAPP, limiting its aggregation into amyloid and thus protecting beta cells from hIAPP-induced toxicity. Thus, increasing islet plasmin activity might be a strategy to limit beta cell loss in type 2 diabetes.


Subject(s)
Fibrinolysin , Insulin-Secreting Cells , Islet Amyloid Polypeptide , Mice, Transgenic , Tissue Plasminogen Activator , Islet Amyloid Polypeptide/metabolism , Animals , Humans , Fibrinolysin/metabolism , Mice , Tissue Plasminogen Activator/metabolism , Insulin-Secreting Cells/metabolism , Insulin-Secreting Cells/drug effects , Islets of Langerhans/metabolism , Islets of Langerhans/drug effects , Diabetes Mellitus, Type 2/metabolism , Up-Regulation/drug effects , Cell Survival/drug effects
2.
Molecules ; 29(15)2024 Jul 26.
Article in English | MEDLINE | ID: mdl-39124908

ABSTRACT

In a landmark study, oleocanthal (OLC), a major phenolic in extra virgin olive oil (EVOO), was found to possess anti-inflammatory activity similar to ibuprofen, involving inhibition of cyclooxygenase (COX) enzymes. EVOO is a rich source of bioactive compounds including fatty acids and phenolics; however, the biological activities of only a small subset of compounds associated with Olea europaea have been explored. Here, the OliveNetTM library (consisting of over 600 compounds) was utilized to investigate olive-derived compounds as potential modulators of the arachidonic acid pathway. Our first aim was to perform enzymatic assays to evaluate the inhibitory activity of a selection of phenolic compounds and fatty acids against COX isoforms (COX-1 and COX-2) and 15-lipoxygenase (15-LOX). Olive compounds were found to inhibit COX isoforms, with minimal activity against 15-LOX. Subsequent molecular docking indicated that the olive compounds possess strong binding affinities for the active site of COX isoforms, and molecular dynamics (MD) simulations confirmed the stability of binding. Moreover, olive compounds were predicted to have favorable pharmacokinetic properties, including a readiness to cross biological membranes as highlighted by steered MD simulations and umbrella sampling. Importantly, olive compounds including OLC were identified as non-inhibitors of the human ether-à-go-go-related gene (hERG) channel based on patch clamp assays. Overall, this study extends our understanding of the bioactivity of Olea-europaea-derived compounds, many of which are now known to be, at least in part, accountable for the beneficial health effects of the Mediterranean diet.


Subject(s)
Anti-Inflammatory Agents , Cyclooxygenase Inhibitors , Molecular Docking Simulation , Olea , Cyclooxygenase Inhibitors/pharmacology , Cyclooxygenase Inhibitors/chemistry , Olea/chemistry , Anti-Inflammatory Agents/pharmacology , Anti-Inflammatory Agents/chemistry , Humans , Molecular Dynamics Simulation , Cyclooxygenase 2/metabolism , Cyclooxygenase 2/chemistry , Cyclooxygenase 1/metabolism , Cyclooxygenase 1/chemistry , Arachidonate 15-Lipoxygenase/metabolism , Arachidonate 15-Lipoxygenase/chemistry , Olive Oil/chemistry , Prostaglandin-Endoperoxide Synthases/metabolism , Phenols/chemistry , Phenols/pharmacology , Plant Extracts/chemistry , Plant Extracts/pharmacology , Phytochemicals/chemistry , Phytochemicals/pharmacology , Cyclopentane Monoterpenes , Computer Simulation , Aldehydes
5.
Molecules ; 29(11)2024 May 23.
Article in English | MEDLINE | ID: mdl-38893322

ABSTRACT

The Mediterranean diet well known for its beneficial health effects, including mood enhancement, is characterised by the relatively high consumption of extra virgin olive oil (EVOO), which is rich in bioactive phenolic compounds. Over 200 phenolic compounds have been associated with Olea europaea, and of these, only a relatively small fraction have been characterised. Utilising the OliveNetTM library, phenolic compounds were investigated as potential inhibitors of the epigenetic modifier lysine-specific demethylase 1 (LSD1). Furthermore, the compounds were screened for inhibition of the structurally similar monoamine oxidases (MAOs) which are directly implicated in the pathophysiology of depression. Molecular docking highlighted that olive phenolics interact with the active site of LSD1 and MAOs. Protein-peptide docking was also performed to evaluate the interaction of the histone H3 peptide with LSD1, in the presence of ligands bound to the substrate-binding cavity. To validate the in silico studies, the inhibitory activity of phenolic compounds was compared to the clinically approved inhibitor tranylcypromine. Our findings indicate that olive phenolics inhibit LSD1 and the MAOs in vitro. Using a cell culture model system with corticosteroid-stimulated human BJ fibroblast cells, the results demonstrate the attenuation of dexamethasone- and hydrocortisone-induced MAO activity by phenolic compounds. The findings were further corroborated using human embryonic stem cell (hESC)-derived neurons stimulated with all-trans retinoic acid. Overall, the results indicate the inhibition of flavin adenine dinucleotide (FAD)-dependent amine oxidases by olive phenolics. More generally, our findings further support at least a partial mechanism accounting for the antidepressant effects associated with EVOO and the Mediterranean diet.


Subject(s)
Molecular Docking Simulation , Monoamine Oxidase Inhibitors , Monoamine Oxidase , Olea , Phenols , Humans , Monoamine Oxidase Inhibitors/pharmacology , Monoamine Oxidase Inhibitors/chemistry , Monoamine Oxidase/metabolism , Monoamine Oxidase/chemistry , Olea/chemistry , Phenols/pharmacology , Phenols/chemistry , Histone Demethylases/antagonists & inhibitors , Histone Demethylases/metabolism , Depression/drug therapy , Olive Oil/chemistry , Computer Simulation
6.
Diabetes Metab Res Rev ; 40(5): e3827, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38837323

ABSTRACT

AIMS: Circadian syndrome (CircS) is considered a better predictor for cardiovascular disease than the metabolic syndrome (MetS). We aim to examine the associations between CircS and MetS with cognition in Chinese adults. METHOD: We used the data of 8546 Chinese adults aged ≥40 years from the 2011 China Health and Retirement Longitudinal Study. MetS was defined using harmonised criteria. CircS included the components of MetS plus short sleep and depression. The cut-off for CircS was set as ≥4. Global cognitive function was assessed during the face-to-face interview. RESULTS: CircS and MetS had opposite associations with the global cognition score and self-reported poor memory. Compared with individuals without the CircS and MetS, the regression coefficients (95%CI) for global cognition score were -1.02 (-1.71 to -0.34) for CircS alone and 0.52 (0.09 to 0.96) for MetS alone in men; -1.36 (-2.00 to -0.72) for CircS alone and 0.60 (0.15 to 1.06) for MetS alone in women. Having CircS alone was 2.53 times more likely to report poor memory in men (95%CI 1.80-3.55) and 2.08 times more likely in women (95%CI 1.54-2.81). In contrast, having MetS alone was less likely to report poor memory (OR 0.64 (0.49-0.84) in men and 0.65 (0.52-0.81) in women). People with CircS and MetS combined were more likely to have self-reported poor memory. CONCLUSIONS: CircS is a strong and better predictor for cognition impairment than MetS in Chinese middle-aged adults. MetS without short sleep and depression is associated with better cognition.


Subject(s)
Cognitive Dysfunction , Metabolic Syndrome , Humans , Metabolic Syndrome/epidemiology , Metabolic Syndrome/psychology , Male , Female , Middle Aged , Cognitive Dysfunction/etiology , Cognitive Dysfunction/epidemiology , China/epidemiology , Longitudinal Studies , Aged , Adult , Prognosis , Chronobiology Disorders/complications , Chronobiology Disorders/epidemiology , Risk Factors , Follow-Up Studies , Circadian Rhythm/physiology
8.
Cardiovasc Diabetol ; 23(1): 107, 2024 Mar 29.
Article in English | MEDLINE | ID: mdl-38553774

ABSTRACT

BACKGROUND: Diabetes-induced trained immunity contributes to the development of atherosclerosis and its complications. This study aimed to investigate in humans whether epigenetic signals involved in immune cell activation and inflammation are initiated in hematopoietic stem/progenitor cells (HSPCs) and transferred to differentiated progeny. METHODS AND RESULTS: High glucose (HG)-exposure of cord blood (CB)-derived HSPCs induced a senescent-associated secretory phenotype (SASP) characterized by cell proliferation lowering, ROS production, telomere shortening, up-regulation of p21 and p27genes, upregulation of NFkB-p65 transcription factor and increased secretion of the inflammatory cytokines TNFα and IL6. Chromatin immunoprecipitation assay (ChIP) of p65 promoter revealed that H3K4me1 histone mark accumulation and methyltransferase SetD7 recruitment, along with the reduction of repressive H3K9me3 histone modification, were involved in NFkB-p65 upregulation of HG-HSPCs, as confirmed by increased RNA polymerase II engagement at gene level. The differentiation of HG-HSPCs into myeloid cells generated highly responsive monocytes, mainly composed of intermediate subsets (CD14hiCD16+), that like the cells from which they derive, were characterized by SASP features and similar epigenetic patterns at the p65 promoter. The clinical relevance of our findings was confirmed in sternal BM-derived HSPCs of T2DM patients. In line with our in vitro model, T2DM HSPCs were characterized by SASP profile and SETD7 upregulation. Additionally, they generated, after myeloid differentiation, senescent monocytes mainly composed of proinflammatory intermediates (CD14hiCD16+) characterized by H3K4me1 accumulation at NFkB-p65 promoter. CONCLUSIONS: Hyperglycemia induces marked chromatin modifications in HSPCs, which, once transmitted to the cell progeny, contributes to persistent and pathogenic changes in immune cell function and composition.


Subject(s)
Diabetes Mellitus, Type 2 , Trained Immunity , Humans , Senescence-Associated Secretory Phenotype , Hematopoietic Stem Cells/metabolism , Antigens, CD34/metabolism , Epigenesis, Genetic , Diabetes Mellitus, Type 2/metabolism , Histone-Lysine N-Methyltransferase/genetics , Histone-Lysine N-Methyltransferase/metabolism
9.
Kidney Int ; 105(1): 132-149, 2024 Jan.
Article in English | MEDLINE | ID: mdl-38069998

ABSTRACT

Glucagon like peptide-1 (GLP-1) is a hormone produced and released by cells of the gastrointestinal tract following meal ingestion. GLP-1 receptor agonists (GLP-1RA) exhibit kidney-protective actions through poorly understood mechanisms. Here we interrogated whether the receptor for advanced glycation end products (RAGE) plays a role in mediating the actions of GLP-1 on inflammation and diabetic kidney disease. Mice with deletion of the GLP-1 receptor displayed an abnormal kidney phenotype that was accelerated by diabetes and improved with co-deletion of RAGE in vivo. Activation of the GLP-1 receptor pathway with liraglutide, an anti-diabetic treatment, downregulated kidney RAGE, reduced the expansion of bone marrow myeloid progenitors, promoted M2-like macrophage polarization and lessened markers of kidney damage in diabetic mice. Single cell transcriptomics revealed that liraglutide induced distinct transcriptional changes in kidney endothelial, proximal tubular, podocyte and macrophage cells, which were dominated by pathways involved in nutrient transport and utilization, redox sensing and the resolution of inflammation. The kidney-protective action of liraglutide was corroborated in a non-diabetic model of chronic kidney disease, the subtotal nephrectomised rat. Thus, our findings identify a novel glucose-independent kidney-protective action of GLP-1-based therapies in diabetic kidney disease and provide a valuable resource for exploring the cell-specific kidney transcriptional response ensuing from pharmacological GLP-1R agonism.


Subject(s)
Diabetes Mellitus, Experimental , Diabetic Nephropathies , Rats , Mice , Animals , Receptor for Advanced Glycation End Products/genetics , Receptor for Advanced Glycation End Products/metabolism , Diabetic Nephropathies/etiology , Diabetic Nephropathies/genetics , Liraglutide/pharmacology , Liraglutide/therapeutic use , Glucagon-Like Peptide-1 Receptor/genetics , Diabetes Mellitus, Experimental/metabolism , Glucagon-Like Peptide 1/metabolism , Glucagon-Like Peptide 1/pharmacology , Glucagon-Like Peptide 1/therapeutic use , Inflammation
10.
Cells Dev ; 177: 203882, 2024 03.
Article in English | MEDLINE | ID: mdl-37956740

ABSTRACT

Phosphorylated histone H2AX (γH2AX) represents a sensitive molecular marker of DNA double-strand breaks (DSBs) and is implicated in stem cell biology. We established a model of mouse embryonic stem cell (mESC) differentiation and examined the dynamics of γH2AX foci during the process. Our results revealed high numbers of γH2AX foci in undifferentiated mESCs, decreasing as the cells differentiated towards the endothelial cell lineage. Notably, we observed two distinct patterns of γH2AX foci: the typical discrete γH2AX foci, which colocalize with the transcriptionally permissive chromatin mark H3K4me3, and the less well-characterized clustered γH2AX regions, which were only observed in intermediate progenitor cells. Next, we explored responses of mESCs to γ-radiation (137Cs). Following exposure to γ-radiation, mESCs showed a reduction in cell viability and increased γH2AX foci, indicative of radiosensitivity. Despite irradiation, surviving mESCs retained their differentiation potential. To further exemplify our findings, we investigated neural stem progenitor cells (NSPCs). Similar to mESCs, NSPCs displayed clustered γH2AX foci associated with progenitor cells and discrete γH2AX foci indicative of embryonic stem cells or differentiated cells. In conclusion, our findings demonstrate that γH2AX serves as a versatile marker of DSBs and may have a role as a biomarker in stem cell differentiation. The distinct patterns of γH2AX foci in differentiating mESCs and NSPCs provide valuable insights into DNA repair dynamics during differentiation, shedding light on the intricate balance between genomic integrity and cellular plasticity in stem cells. Finally, the clustered γH2AX foci observed in intermediate progenitor cells is an intriguing feature, requiring further exploration.


Subject(s)
DNA Repair , Mouse Embryonic Stem Cells , Animals , Mice , DNA Repair/genetics , DNA Breaks, Double-Stranded , Embryonic Stem Cells , Cell Differentiation/genetics
11.
Signal Transduct Target Ther ; 9(1): 2, 2024 01 01.
Article in English | MEDLINE | ID: mdl-38161208

ABSTRACT

ß-cells are a type of endocrine cell found in pancreatic islets that synthesize, store and release insulin. In type 1 diabetes (T1D), T-cells of the immune system selectively destroy the insulin-producing ß-cells. Destruction of these cells leads to a lifelong dependence on exogenous insulin administration for survival. Consequently, there is an urgent need to identify novel therapies that stimulate ß-cell growth and induce ß-cell function. We and others have shown that pancreatic ductal progenitor cells are a promising source for regenerating ß-cells for T1D owing to their inherent differentiation capacity. Default transcriptional suppression is refractory to exocrine reaction and tightly controls the regenerative potential by the EZH2 methyltransferase. In the present study, we show that transient stimulation of exocrine cells, derived from juvenile and adult T1D donors to the FDA-approved EZH2 inhibitors GSK126 and Tazemetostat (Taz) influence a phenotypic shift towards a ß-like cell identity. The transition from repressed to permissive chromatin states are dependent on bivalent H3K27me3 and H3K4me3 chromatin modification. Targeting EZH2 is fundamental to ß-cell regenerative potential. Reprogrammed pancreatic ductal cells exhibit insulin production and secretion in response to a physiological glucose challenge ex vivo. These pre-clinical studies underscore the potential of small molecule inhibitors as novel modulators of ductal progenitor differentiation and a promising new approach for the restoration of ß-like cell function.


Subject(s)
Diabetes Mellitus, Type 1 , Islets of Langerhans , Humans , Diabetes Mellitus, Type 1/drug therapy , Diabetes Mellitus, Type 1/genetics , Diabetes Mellitus, Type 1/metabolism , Islets of Langerhans/metabolism , Insulin/metabolism , Cell Differentiation/genetics , Chromatin/metabolism , Enhancer of Zeste Homolog 2 Protein/genetics , Enhancer of Zeste Homolog 2 Protein/metabolism
12.
Molecules ; 28(24)2023 Dec 05.
Article in English | MEDLINE | ID: mdl-38138436

ABSTRACT

Genetic abnormalities have been associated with primary aldosteronism, a major cause of secondary hypertension. This includes mutations in the KCNJ5 gene, which encodes G protein-gated inwardly rectifying K+ channel 4 (GIRK4). For example, the substitution of glycine with glutamic acid gives rise to the pathogenic GIRK4G151E mutation, which alters channel selectivity, making it more permeable to Na+ and Ca2+. While tertiapin and tertiapin-Q are well-known peptide inhibitors of the GIRK4WT channel, clinically, there is a need for the development of selective modulators of mutated channels, including GIRK4G151E. Using in silico methods, including homology modeling, protein-peptide docking, ligand-binding site prediction, and molecular docking, we aimed to explore potential modulators of GIRK4WT and GIRK4G151E. Firstly, protein-peptide docking was performed to characterize the binding site of tertiapin and its derivative to the GIRK4 channels. In accordance with previous studies, the peptide inhibitors preferentially bind to the GIRK4WT channel selectivity filter compared to GIRK4G151E. A ligand-binding site analysis was subsequently performed, resulting in the identification of two potential regions of interest: the central cavity and G-loop gate. Utilizing curated chemical libraries, we screened over 700 small molecules against the central cavity of the GIRK4 channels. Flavonoids, including luteolin-7-O-rutinoside and rutin, and the macrolides rapamycin and troleandomycin bound strongly to the GIRK4 channels. Similarly, xanthophylls, particularly luteoxanthin, bound to the central cavity with a strong preference towards the mutated GIRK4G151E channel compared to GIRK4WT. Overall, our findings suggest potential lead compounds for further investigation, particularly luteoxanthin, that may selectively modulate GIRK4 channels.


Subject(s)
G Protein-Coupled Inwardly-Rectifying Potassium Channels , Hypertension , Humans , G Protein-Coupled Inwardly-Rectifying Potassium Channels/genetics , G Protein-Coupled Inwardly-Rectifying Potassium Channels/metabolism , Ligands , Molecular Docking Simulation , GTP-Binding Proteins/metabolism , Peptides/metabolism , Drug Discovery
14.
Diabetes Res Clin Pract ; 204: 110918, 2023 Oct.
Article in English | MEDLINE | ID: mdl-37748713

ABSTRACT

AIMS: To investigate epigenomic indices of diabetic kidney disease (DKD) susceptibility among high-risk populations with type 2 diabetes mellitus. METHODS: KDIGO (Kidney Disease: Improving Global Outcomes) clinical guidelines were used to classify people living with or without DKD. Differential gene methylation of DKD was then assessed in a discovery Aboriginal Diabetes Study cohort (PROPHECY, 89 people) and an external independent study from Thailand (THEPTARIN, 128 people). Corresponding mRNA levels were also measured and linked to levels of albuminuria and eGFR. RESULTS: Increased DKD risk was associated with reduced methylation and elevated gene expression in the PROPHECY discovery cohort of Aboriginal Australians and these findings were externally validated in the THEPTARIN diabetes registry of Thai people living with type 2 diabetes mellitus. CONCLUSIONS: Novel epigenomic scores can improve diagnostic performance over clinical modelling using albuminuria and GFR alone and can distinguish DKD susceptibility.


Subject(s)
Diabetes Mellitus, Type 2 , Diabetic Nephropathies , Humans , Diabetes Mellitus, Type 2/complications , Albuminuria/complications , Disease Susceptibility/complications , Epigenomics , Australia , Kidney , Diabetic Nephropathies/diagnosis , Diabetic Nephropathies/genetics , Diabetic Nephropathies/metabolism , Biomarkers , Glomerular Filtration Rate
15.
Cell Mol Life Sci ; 80(9): 248, 2023 Aug 14.
Article in English | MEDLINE | ID: mdl-37578596

ABSTRACT

Human erythroleukemic K562 cells represent the prototypical cell culture model of chronic myeloid leukemia (CML). The cells are pseudo-triploid and positive for the Philadelphia chromosome. Therefore, K562 cells have been widely used for investigating the BCR/ABL1 oncogene and the tyrosine kinase inhibitor, imatinib-mesylate. Further, K562 cells overexpress transferrin receptors (TfR) and have been used as a model for targeting cytotoxic therapies, via receptor-mediated endocytosis. Here, we have characterized K562 cells focusing on the karyotype of cells in prolonged culture, regulation of expression of TfR in wildtype (WT) and doxorubicin-resistant cells, and responses to histone deacetylase inhibition (HDACi). Karyotype analysis indicates novel chromosomes and gene expression analysis suggests a shift of cultured K562 cells away from patient-derived leukemic cells. We confirm the high expression of TfR on K562 cells using immunofluorescence and cell-surface receptor binding radioassays. Importantly, high TfR expression is observed in patient-derived cells, and we highlight the persistent expression of TfR following doxorubicin acquired resistance. Epigenetic analysis indicates that permissive histone acetylation and methylation at the promoter region regulates the transcription of TfR in K562 cells. Finally, we show relatively high expression of HDAC enzymes in K562 cells and demonstrate the chemotoxic effects of HDACi, using the FDA-approved hydroxamic acid, vorinostat. Together with a description of morphology, infrared spectral analysis, and examination of metabolic properties, we provide a comprehensive characterization of K562 cells. Overall, K562 cell culture systems remain widely used for the investigation of novel therapeutics for CML, which is particularly important in cases of imatinib-mesylate resistance.


Subject(s)
Fusion Proteins, bcr-abl , Leukemia, Myelogenous, Chronic, BCR-ABL Positive , Humans , Imatinib Mesylate/pharmacology , Imatinib Mesylate/therapeutic use , K562 Cells , Fusion Proteins, bcr-abl/genetics , Transferrin , Pyrimidines/pharmacology , Drug Resistance, Neoplasm/genetics , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/metabolism , Histone Deacetylases/metabolism , Doxorubicin/pharmacology , Doxorubicin/therapeutic use , Receptors, Transferrin/genetics , Chromosomes/metabolism , Mesylates/pharmacology , Apoptosis
16.
Clin Epigenetics ; 15(1): 101, 2023 06 12.
Article in English | MEDLINE | ID: mdl-37309004

ABSTRACT

BACKGROUND: Therapeutic replacement of pancreatic endocrine ß-cells is key to improving hyperglycaemia caused by insulin-dependent diabetes . Whilst the pool of ductal progenitors, which give rise to the endocrine cells, are active during development, neogenesis of islets is repressed in the human adult. Recent human donor studies have demonstrated the role of EZH2 inhibition in surgically isolated exocrine cells showing reactivation of insulin expression and the influence on the H3K27me3 barrier to ß-cell regeneration. However, those studies fall short on defining the cell type active in transcriptional reactivation events. This study examines the role of the regenerative capacity of human pancreatic ductal cells when stimulated with pharmacological inhibitors of the EZH2 methyltransferase. RESULTS: Human pancreatic ductal epithelial cells were stimulated with the EZH2 inhibitors GSK-126, EPZ6438, and triptolide using a 2- and 7-day protocol to determine their influence on the expression of core endocrine development marker NGN3, as well as ß-cell markers insulin, MAFA, and PDX1. Chromatin immunoprecipitation studies show a close correspondence of pharmacological EZH2 inhibition with reduced H3K27me3 content of the core genes, NGN3, MAFA and PDX1. Consistent with the reduction of H3K27me3 by pharmacological inhibition of EZH2, we observe measurable immunofluorescence staining of insulin protein and glucose-sensitive insulin response. CONCLUSION: The results of this study serve as a proof of concept for a probable source of ß-cell induction from pancreatic ductal cells that are capable of influencing insulin expression. Whilst pharmacological inhibition of EZH2 can stimulate secretion of detectable insulin from ductal progenitor cells, further studies are required to address mechanism and the identity of ductal progenitor cell targets to improve likely methods designed to reduce the burden of insulin-dependent diabetes.


Subject(s)
Diabetes Mellitus, Type 1 , Insulin , Adult , Humans , Histones , DNA Methylation , Epithelial Cells , Enhancer of Zeste Homolog 2 Protein
17.
Cardiovasc Eng Technol ; 14(4): 605-614, 2023 08.
Article in English | MEDLINE | ID: mdl-37165253

ABSTRACT

PURPOSE: The Lumi-Solve photo-angioplasty drug eluting balloon catheter (DEBc) may afford safety advantages over current DEBc. Lumi-Solve utilises the guidewire (GW) port and lumen to deliver fibre-optic UV365nm light to the angioplasty balloon which may be problematic. We explore and evaluate alternative Lumi-Solve design options to circumvent fibre-optic use of the GW port and lumen which may enhance efficacy and clinical utility. METHODS: Effects of guidewire shadowing (GWS) on visible and UV365nm light transmission were evaluated and modelled in-silico. To evaluate the effect of a dedicated intra-balloon fibre-optic port, modified angioplasty balloons and sections of translucent polyethylene terephthalate (PET) GW port tubing were utilised. Investigation of the effect of GWS on chemical and biological photo-activation of balloon surface drug was performed utilising LCMS analysis and inhibition of histone deacetylase activity (HDACi) was measured in human umbilical vein endothelial cells (HUVEC). RESULTS: Parallel fibre-optic and GW port configurations generated a GWS of approximately 18.0% of the evaluable balloon surface area and attenuated both visible and UV light intensity by 20.0-25.0% and reduced chemical photo-activation of balloon surface drug and HDACi by at least 40-45%. Alternative fibre-optic port configurations including a spiral design significantly mitigated GWS effects on UV light transmission. CONCLUSIONS: To avoid use of the GW port and its associated complications a dedicated third port and lumen for the Lumi-Solve fibre-optic may be required. To maximize balloon surface chemical and biological photo-activation, non-parallel, intra-balloon, fibre-optic lumen trajectories, including a spiral design may be useful.


Subject(s)
Angioplasty, Balloon , Vascular Access Devices , Humans , Angioplasty, Balloon/adverse effects , Human Umbilical Vein Endothelial Cells
18.
Cell Mol Gastroenterol Hepatol ; 16(1): 63-81, 2023.
Article in English | MEDLINE | ID: mdl-36965814

ABSTRACT

BACKGROUND & AIMS: Hepatocellular carcinoma (HCC) is a model of a diverse spectrum of cancers because it is induced by well-known etiologies, mainly hepatitis C virus (HCV) and hepatitis B virus. Here, we aimed to identify HCV-specific mutational signatures and explored the link between the HCV-related regional variation in mutations rates and HCV-induced alterations in genome-wide chromatin organization. METHODS: To identify an HCV-specific mutational signature in HCC, we performed high-resolution targeted sequencing to detect passenger mutations on 64 HCC samples from 3 etiology groups: hepatitis B virus, HCV, or other. To explore the link between the genomic signature and genome-wide chromatin organization we performed chromatin immunoprecipitation sequencing for the transcriptionally permissive H3K4Me3, H3K9Ac, and suppressive H3K9Me3 modifications after HCV infection. RESULTS: Regional variation in mutation rate analysis showed significant etiology-dependent regional mutation rates in 12 genes: LRP2, KRT84, TMEM132B, DOCK2, DMD, INADL, JAK2, DNAH6, MTMR9, ATM, SLX4, and ARSD. We found an enrichment of C->T transversion mutations in the HCV-associated HCC cases. Furthermore, these cases showed regional variation in mutation rates associated with genomic intervals in which HCV infection dictated epigenetic alterations. This signature may be related to the HCV-induced decreased expression of genes encoding key enzymes in the base excision repair pathway. CONCLUSIONS: We identified novel distinct HCV etiology-dependent mutation signatures in HCC associated with HCV-induced alterations in histone modification. This study presents a link between cancer-causing mutagenesis and the increased predisposition to liver cancer in chronic HCV-infected individuals, and unveils novel etiology-specific mechanisms leading to HCC and cancer in general.


Subject(s)
Carcinoma, Hepatocellular , Hepatitis C , Liver Neoplasms , Humans , Liver Neoplasms/pathology , Carcinoma, Hepatocellular/pathology , Hepatitis C/complications , Hepatitis C/genetics , Mutation/genetics , Hepacivirus/genetics , Hepatitis B virus/genetics , Epigenesis, Genetic/genetics , Chromatin , Genomics , Protein Tyrosine Phosphatases, Non-Receptor/genetics , Keratins, Type II/genetics , Keratins, Hair-Specific/genetics
19.
J Clin Invest ; 133(4)2023 02 15.
Article in English | MEDLINE | ID: mdl-36633903

ABSTRACT

Diabetic nephropathy (DN) is a polygenic disorder with few risk variants showing robust replication in large-scale genome-wide association studies. To understand the role of DNA methylation, it is important to have the prevailing genomic view to distinguish key sequence elements that influence gene expression. This is particularly challenging for DN because genome-wide methylation patterns are poorly defined. While methylation is known to alter gene expression, the importance of this causal relationship is obscured by array-based technologies since coverage outside promoter regions is low. To overcome these challenges, we performed methylation sequencing using leukocytes derived from participants of the Finnish Diabetic Nephropathy (FinnDiane) type 1 diabetes (T1D) study (n = 39) that was subsequently replicated in a larger validation cohort (n = 296). Gene body-related regions made up more than 60% of the methylation differences and emphasized the importance of methylation sequencing. We observed differentially methylated genes associated with DN in 3 independent T1D registries originating from Denmark (n = 445), Hong Kong (n = 107), and Thailand (n = 130). Reduced DNA methylation at CTCF and Pol2B sites was tightly connected with DN pathways that include insulin signaling, lipid metabolism, and fibrosis. To define the pathophysiological significance of these population findings, methylation indices were assessed in human renal cells such as podocytes and proximal convoluted tubule cells. The expression of core genes was associated with reduced methylation, elevated CTCF and Pol2B binding, and the activation of insulin-signaling phosphoproteins in hyperglycemic cells. These experimental observations also closely parallel methylation-mediated regulation in human macrophages and vascular endothelial cells.


Subject(s)
Diabetes Mellitus, Type 1 , Diabetic Nephropathies , Humans , Diabetes Mellitus, Type 1/complications , Diabetes Mellitus, Type 1/genetics , Diabetic Nephropathies/genetics , Diabetic Nephropathies/metabolism , Genome-Wide Association Study , Endothelial Cells/metabolism , DNA Methylation , Insulin/metabolism
20.
Cardiovasc Res ; 119(2): 357-370, 2023 03 31.
Article in English | MEDLINE | ID: mdl-35389425

ABSTRACT

The influence of cellular metabolism on epigenetic pathways is well documented but misunderstood. Scientists have long known of the metabolic impact on epigenetic determinants. More often than not, that title role for DNA methylation was portrayed by the metabolite S-adenosylmethionine. Technically speaking, there are many other metabolites that drive epigenetic processes that instruct seemingly distant-yet highly connect pathways-and none more so than our understanding of the cancer epigenome. Recent studies have shown that available energy links the extracellular environment to influence cellular responses. This focused review examines the recent interest in epigenomics and casts cancer, metabolism, and immunity in unfamiliar roles-cooperating. There are not only language lessons from cancer research, we have come round to appreciate that reaching into areas previously thought of as too distinct are also object lessons in understanding health and disease. The Warburg effect is one such signature of how glycolysis influences metabolic shift during oncogenesis. That shift in metabolism-now recognized as central to proliferation in cancer biology-influences core enzymes that not only control gene expression but are also central to replication, condensation, and the repair of nucleic acid. These nuclear processes rely on metabolism, and with glucose at centre stage, the role of respiration and oxidative metabolism is now synonymous with the mitochondria as the powerhouses of metaboloepigenetics. The emerging evidence for metaboloepigenetics in trained innate immunity has revealed recognizable signalling pathways with antecedent extracellular stimulation. With due consideration to immunometabolism, we discuss the striking signalling similarities influencing these core pathways. The immunometabolic-epigenetic axis in cardiovascular disease has deeply etched connections with inflammation, and we examine the chromatin template as a carrier of epigenetic indices that determine the expression of genes influencing atherosclerosis and vascular complications of diabetes.


Subject(s)
Cardiovascular Diseases , Neoplasms , Humans , Cardiovascular Diseases/genetics , Epigenesis, Genetic , DNA Methylation , Chromatin , Glycolysis , Immunity, Innate/genetics , Neoplasms/genetics
SELECTION OF CITATIONS
SEARCH DETAIL