UVRAG (UV radiation resistance associated) is an important regulator of mammalian macroautophagy/autophagy by interacting with BECN1, PIK3C3, and RUBCN. Phosphorylation of UVRAG by MTORC1 negatively regulates autophagosome maturation under nutrient-enriched conditions. However, how UVRAG ubiquitination is regulated is still unknown. Here we report that UVRAG is ubiquitinated by SMURF1 at lysine residues 517 and 559, which decreases the association of UVRAG with RUBCN and promotes autophagosome maturation. However, the deubiquitinase ZRANB1 specifically cleaves SMURF1-induced K29 and K33-linked polyubiquitin chains from UVRAG, thereby increasing the binding of UVRAG to RUBCN and inhibiting autophagy flux. We also demonstrate that CSNK1A1-mediated UVRAG phosphorylation at Ser522 disrupts the binding of SMURF1 to UVRAG through PPxY motif and blocks UVRAG ubiquitination-mediated autophagosome maturation. Interestingly, ZRANB1 is phosphorylated at Thr35, and Ser209 residues by CSNK1A1, and this phosphorylation activates its deubiquitinating activity. Importantly, we provide in vitro and in vivo evidence that UVRAG ubiquitination at lysine residues 517 and 559 or prevention of Ser522 phosphorylation by D4476, a CSNK1A1 inhibitor, enhances the lysosomal degradation of EGFR, which significantly inhibits hepatocellular carcinoma (HCC) growth. Furthermore, UVRAG S522 phosphorylation levels correlate with ZRANB1 T35/S209 phosphorylation levels and poor prognosis in HCC patients. These findings identify a novel molecular mechanism by which ubiquitination and phosphorylation of UVRAG regulate its function in autophagosome maturation and HCC growth, encouraging further study of their potential therapeutic implications. Abbreviations: ATG: autophagy related; BafA 1 : bafilomycin A 1 ; BECN1: beclin 1; CHX: cycloheximide; CSNK1A1/CK1α: casein kinase 1 alpha 1; CQ: chloroquine; DUB: deubiquitinase; EBSS: Earle’s balanced salt solution; EGF: epidermal growth factor; GFP: green fluorescent protein; GST: glutathione S-transferase; HBSS: Hanks balanced salts solution; HCC: hepatocellular carcinoma; MAP1LC3B/LC3: microtubule associated protein 1 light chain 3 beta; MEFs: mouse embryo fibroblasts; mRFP: monomeric red fluorescent protein; PIK3C3 / VPS34: phosphatidylinositol 3-kinase catalytic subunit type 3; PTMs: post-translational modifications; RUBCN: rubicon autophagy regulator; siRNA: small interfering RNA; SMURF1: SMAD specific E3 ubiquitin protein ligase 1; SQSTM1: sequestosome 1; Ub-AMC: ubiquitin-7-amido-4-methylcoumarin: a fluorogenic substrate; UVRAG: UV radiation resistance associated; ZRANB1/TRABID: zinc finger RANBP2-type containing 1
Our results suggest that LOC554202 may play an important role in the progression of chordoma by the direct upregulation of EZH2 and indirect promotion of RNF144B via miR-31.
OBJECTIVEHyperglycemia, inflammation, and oxidative stress are thought to be involved in the pathogenesis of cognitive decline. Dipeptidyl peptidase-4 (DPP4) is a newly identified adipokine related to these risk factors. Hence, we aimed to investigate the association between plasma DPP4 activities and mild cognitive impairment (MCI) in elderly patients with type 2 diabetes. RESEARCH DESIGN AND METHODSWe evaluated plasma DPP4 activity, inflammatory markers, and oxidative stress parameters in a cross-sectional sample of 1,160 patients with type 2 diabetes aged 60 years or older in China. MCI was diagnosed based on criteria established by the National Institute on Aging-Alzheimer's Association workgroups RESULTSPatients in the highest quartile of DPP4 activity had higher HbA 1c , interleukin 6 (IL-6), CRP, nitrotyrosine, 8-iso-PGF2a, and lower Montreal Cognitive Assessment (MoCA) scores compared with subjects in the lowest quartile (P < 0.001). In the highest DPP4 quartile, MCI risk was higher (odds ratio 3.49; 95% CI 1.97-4.57) than in the lowest quartile after adjustment for potential confounders. The risk for MCI increased more with higher levels of DPP4 activity, IL-6, CRP, nitrotyrosine, and 8-iso-PGF2a (P < 0.05), but not with higher levels of HbA 1c . CONCLUSIONSThis study shows that increased DPP4 activities are independently associated with MCI in elderly patients with type 2 diabetes. The mechanisms might be partly explained by the effect of DPP4 on inflammation and oxidative stress. These observations raise further interest in DPP4 activity for its potential effect on these MCI-related risk factors as a biological marker or even a possible therapeutic target for MCI.Type 2 diabetes is associated with an increased risk of accelerated age-related cognitive impairment and a higher incidence of dementia (1). Dementia is generally preceded by an intermediate stage, termed mild cognitive impairment (MCI), in which patients have cognitive complaints and objective disturbances on cognitive tests but in which their daily functioning is largely preserved (2). Although not all
Cancer stem cells (CSCs) have been reported to play critical roles in tumor initiation, propagation, and regeneration of cancer. Nano-size vehicles are employed to deliver drugs to target the CSCs for cancer therapy. Polymeric nanoparticles have been considered as the most efficient vehicles for drug delivery due to their excellent pharmacokinetic properties. The CSCs specific antibodies or ligands can be conjugated onto the surface or interior of nanoparticles to successfully target and finally eliminate CSCs. In this review, we focus on the approaches of polymeric nanoparticles design for loading drug, and their potential application for CSCs targeting in cancer therapy.
The combined genetic tests of JAK2 V617F, JAK2 exon 12, MPL exon 10, and CALR exon 9 help improve the diagnostic rate for BCR-ABL1-negative MPN.
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