Search results for "Quitina"

Alternative Splice Forms of CYLD Mediate Ubiquitination of SMAD7 to Prevent TGFB Signaling and Promote Colitis

2018

Background & Aims The CYLD lysine 63 deubiquitinase gene (CYLD) encodes tumor suppressor protein that is mutated in familial cylindromatosus, and variants have been associated with Crohn disease (CD). Splice forms of CYLD that lack exons 7 and 8 regulate transcription factors and functions of immune cells. We examined the expression of splice forms of CYLD in colon tissues from patients with CD and their effects in mice. Methods We performed immunohistochemical analyses of colon tissues from patients with untreated CD and patients without inflammatory bowel diseases (controls). We obtained mice that expressed splice forms of CYLD (sCYLD mice) without or with SMAD7 (sCYLD/SMAD7 mice) from tr…

2020

Over the last decade, the E3-ubiquitine ligases from IAP (Inhibitor of Apoptosis) family have emerged as potent regulators of immune response. In immune cells, they control signaling pathways driving differentiation and inflammation in response to stimulation of tumor necrosis factor receptor (TNFR) family, pattern-recognition receptors (PRRs), and some cytokine receptors. They are able to control the activity, the cellular fate, or the stability of actors of signaling pathways, acting at different levels from components of receptor-associated multiprotein complexes to signaling effectors and transcription factors, as well as cytoskeleton regulators. Much less is known about ubiquitination …

Synthetic Polyclonal-Derived CDR Peptides as an Innovative Strategy in Glaucoma Therapy

2019

The pathogenesis of glaucoma is strongly associated with the occurrence of autoimmune-mediated loss of retinal ganglion cells (RGCs) and additionally, recent evidence shows that specific antibody-derived signature peptides are significantly differentially expressed in sera of primary-open angle glaucoma patients (POAG) compared to healthy controls. Synthetically antibody-derived peptides can modulate various effector functions of the immune system and act as antimicrobial or antiviral molecules. In an ex vivo adolescent glaucoma model, this study, for the first time, demonstrates that polyclonal-derived complementarity-determining regions (CDRs) can significantly increase the survival rate …

Tif1γ regulates the TGF-β1 receptor and promotes physiological aging of hematopoietic stem cells.

2014

The hematopoietic system declines with age. Myeloid-biased differentiation and increased incidence of myeloid malignancies feature aging of hematopoietic stem cells (HSCs), but the mechanisms involved remain uncertain. Here, we report that 4-mo-old mice deleted for transcription intermediary factor 1γ (Tif1γ) in HSCs developed an accelerated aging phenotype. To reinforce this result, we also show that Tif1γ is down-regulated in HSCs during aging in 20-mo-old wild-type mice. We established that Tif1γ controls TGF-β1 receptor (Tgfbr1) turnover. Compared with young HSCs, Tif1γ(-/-) and old HSCs are more sensitive to TGF-β signaling. Importantly, we identified two populations of HSCs specifical…

BAG3 and friends: co-chaperones in selective autophagy during aging and disease.

2011

There is a reciprocal change in the expression of two members of the BAG (Bcl-2-associated athanogen) family, BAG1 and BAG3, during cellular aging and under acute stress ("BAG1-BAG3-switch"). BAG3 was recently described as a mediator of a novel macroautophagy pathway that uses the specificity of heat shock protein 70 (HSP70) to misfolded proteins and also involves other protein partners, such as HSPB8. Also crucial for induction and execution of autophagy are sequestosome-1/p62 (SQSTM1/p62) and LC3, an autophagosome-associated protein. In this novel pathway, BAG3 mediates the targeting and transport of degradation-prone substrates into aggresomes via the microtubule-motor dynein. Interestin…

Protein quality control during aging involves recruitment of the macroautophagy pathway by BAG3.

2009

The Hsc/Hsp70 co-chaperones of the BAG (Bcl-2-associated athanogene) protein family are modulators of protein quality control. We examined the specific roles of BAG1 and BAG3 in protein degradation during the aging process. We show that BAG1 and BAG3 regulate proteasomal and macroautophagic pathways, respectively, for the degradation of polyubiquitinated proteins. Moreover, using models of cellular aging, we find that a switch from BAG1 to BAG3 determines that aged cells use more intensively the macroautophagic system for turnover of polyubiquitinated proteins. This increased macroautophagic flux is regulated by BAG3 in concert with the ubiquitin-binding protein p62/SQSTM1. The BAG3/BAG1 ra…

Luminal Lipid Regulates CD36 Levels and Downstream Signaling to Stimulate Chylomicron Synthesis

2011

International audience; The membrane glycoprotein CD36 binds nanomolar concentrations of long chain fatty acids (LCFA) and is highly expressed on the luminal surface of enterocytes. CD36 deficiency reduces chylomicron production through unknown mechanisms. In this report, we provide novel insights into some of the underlying mechanisms. Our in vivo data demonstrate that CD36 gene deletion in mice does not affect LCFA uptake and subsequent esterification into triglycerides by the intestinal mucosa exposed to the micellar LCFA concentrations prevailing in the intestine. In rodents, the CD36 protein disappears early from the luminal side of intestinal villi during the postprandial period, but …

Cylindromatosis (Cyld) gene mutation in T cells promotes the development of an IL-9-dependent allergic phenotype in experimental asthma

2016

Cylindromatosis (CYLD) is a ubiquitously expressed deubiquitinating enzyme which removes activating ubiquitin residues from important signaling molecules of the NF-κB pathway. In CYLDex7/8 transgenic mice, a naturally occurring short isoform (sCYLD) is overexpressed in the absence of full length CYLD, leading to excessive NF-κB activity. Herein, we investigated the impact of the CYLDex7/8 mutation selectively in T cells on the development of experimental allergic airway disease induced by sensitization and challenge with ovalbumin. Compared with their wildtype littermates, mice bearing the T cell-specific mutation (CD4+CYLDex7/8) display stronger eosinophilia and mucus production in the lun…

Down-regulation of CYLD as a trigger for NF-κB activation and a mechanism of apoptotic resistance in hepatocellular carcinoma cells

2010

The cylindromatosis gene (CYLD) was identified as a tumor suppressor gene, which is mutated in familial cylindromatosis (Brooke-Spiegler syndrome), an autosomal-dominant predisposition to multiple tumors of the skin appendages. CYLD is a deubiquitinating enzyme acting as a negative regulator of the nuclear factor κB (NF-κB) signaling pathway by removing lysine-63-linked polyubiquitin chains from NF-κB activating proteins. In order to investigate the role of CYLD in apoptotic signaling in human hepatocellular carcinoma (HCC) cells, we first studied the expression levels of CYLD in HCC tissues. CYLD expression was lower in HCC both at protein and mRNA levels compared to the surrounding non-ma…

OTUB1 inhibits CNS autoimmunity by preventing IFN-γ-induced hyperactivation of astrocytes.

2019

Astrocytes are critical regulators of neuroinflammation in multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE). Growing evidence indicates that ubiquitination of signaling molecules is an important cell‐intrinsic mechanism governing astrocyte function during MS and EAE. Here, we identified an upregulation of the deubiquitinase OTU domain, ubiquitin aldehyde binding 1 (OTUB1) in astrocytes during MS and EAE. Mice with astrocyte‐specific OTUB1 ablation developed more severe EAE due to increased leukocyte accumulation, proinflammatory gene transcription, and demyelination in the spinal cord as compared to control mice. OTUB1‐deficient astrocytes were hy…