Gut
Institute of Pediatrics, University of Foggia, viale Pinto 1, Foggia 71100, Italy.
Published: March 2010
Background: An unresolved question in coeliac disease is to understand how some toxic gliadin peptides, in particular p31-43, can initiate an innate response and lead to tissue transglutaminase (TG2) upregulation in coeliac intestine and gliadin sensitive epithelial cell lines. Aim We addressed whether the epithelial uptake of p31-43 induces an intracellular pro-oxidative envoronment favouring TG2 activation and leading to the innate immune response.
Methods: The time course of intracellular delivery to lysosomes of p31-43, palpha-2 or palpha-9 gliadin peptides was analysed in T84 and Caco-2 epithelial cells. The effects of peptide challenge on oxidative stress, TG2 and peroxisome proliferator-activated receptor (PPAR)gamma ubiquitination and p42/44-mitogen activated protein (MAP) kinase or tyrosine phosphorylation were investigated in cell lines and cultured coeliac disease biopsies with/without anti-oxidant treatment or TG2 gene silencing by immunoprecipitation, western blot, confocal microscopy and Fluorenscence Transfer Resonance Energy (FRET) analysis.
Results: After 24 h of challenge p31-43, but not palpha-2 or palpha-9, is still retained within LAMP1-positive perinuclear vesicles and leads to increased levels of reactive oxygen species (ROS) that inhibit TG2 ubiquitination and lead to increases of TG2 protein levels and activation. TG2 induces cross-linking, ubiquitination and proteasome degradation of PPARgamma. Treatment with the antioxidant EUK-134 as well as TG2 gene silencing restored PPARgamma levels and reversed all monitored signs of innate activation, as indicated by the dramatic reduction of tyrosine and p42/p44 phosphorylation.
Conclusion: p31-43 accumulation in lysosomes leads to epithelial activation via the ROS-TG2 axis. TG2 works as a rheostat of ubiquitination and proteasome degradation and drives inflammation via PPARgamma downregulation.
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http://dx.doi.org/10.1136/gut.2009.183608 | DOI Listing |
Nature
January 2025
Nash Family Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
Histone H3 monoaminylations at Gln5 represent an important family of epigenetic marks in brain that have critical roles in permissive gene expression. We previously demonstrated that serotonylation and dopaminylation of Gln5 of histone H3 (H3Q5ser and H3Q5dop, respectively) are catalysed by transglutaminase 2 (TG2), and alter both local and global chromatin states. Here we found that TG2 additionally functions as an eraser and exchanger of H3 monoaminylations, including H3Q5 histaminylation (H3Q5his), which displays diurnally rhythmic expression in brain and contributes to circadian gene expression and behaviour.
View Article and Find Full Text PDFBiomolecules
December 2024
Department of Anesthesiology and Perioperative Medicine, University of Rochester, 601 Elmwood Ave, Box 604, Rochester, NY 14620, USA.
Astrocytes play critical roles in supporting structural and metabolic homeostasis in the central nervous system (CNS). CNS injury leads to the development of a range of reactive phenotypes in astrocytes whose molecular determinants are poorly understood. Finding ways to modulate astrocytic injury responses and leverage a pro-recovery phenotype holds promise in treating CNS injury.
View Article and Find Full Text PDFAging Cell
January 2025
MOE Key Laboratory of Bioinformatics, Center for Synthetic and Systematic Biology, School of Life Sciences, Tsinghua University, Beijing, People's Republic of China.
Microglia, as resident immune cells in the central nervous system (CNS), play a crucial role in maintaining homeostasis and phagocytosing metabolic waste in the brain. Senescent microglia exhibit decreased phagocytic capacity and increased neuroinflammation through senescence-associated secretory phenotype (SASP). This process contributes to the development of various neurodegenerative diseases, including Alzheimer's disease (AD).
View Article and Find Full Text PDFCytojournal
November 2024
Department of Cardiology, Huashan Hospital, Fudan University, Shanghai, China.
Objective: Macrophages perform vital functions in cardiac remodeling after myocardial infarction (MI). Transglutaminase 2 (TG2) participates in fibrosis. Nevertheless, the role of TG2 in MI and mechanisms underlying macrophage polarization are unclear.
View Article and Find Full Text PDFLife Sci
December 2024
State Key Laboratory of Animal Biotech Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences (CAAS), Beijing 100193, China. Electronic address:
Aims: This study aimed to explore the molecular pathological mechanisms of the liver in metabolic disease-susceptible transgenic pigs via multiomics analysis.
Materials And Methods: The triple-transgenic (PNPLA3-GIPR-hIAPP) pig model (TG pig) was successfully constructed in our laboratory via the CRISPR/Cas9 technique previously described. Wild-type (WT) pigs and TG pigs after 2 or 12 months of high-fat and high-sucrose diet (HFHSD) induction (WT2, TG2, WT12, and TG12 groups, respectively) were used as materials.
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