Результаты поиска

Split-Luciferase Reassembly Assay to Measure Endoplasmic Reticulum-Mitochondria Contacts in Live Cells.

Endoplasmic reticulum (ER)-mitochondria contact sites play a critical role in cell health and homeostasis, such as the regulation of Ca2+ and lipid homeostasis, mitochondrial dynamics, autophagosome and mitophagosome biogenesis, and apoptosis. Failure to maintain normal ER-mitochondrial coupling is implicated in many neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and hereditary spastic paraplegia. It is of considerable significance to explore how the dysregulation of ER-mitochondrial contacts could lead to cell death and whether repa

SQSTM1/p62 and Hepatic Mallory-Denk Body Formation in Alcohol-Associated Liver Disease.

Sequestosome 1 (SQSTM1/p62; hereafter p62) is an autophagy receptor protein for selective autophagy primarily due to its direct interaction with the microtubule light chain 3 protein that specifically localizes on autophagosome membranes. As a result, impaired autophagy leads to the accumulation of p62. p62 is also a common component of many human liver disease-related cellular inclusion bodies, such as Mallory-Denk bodies, intracytoplasmic hyaline bodies, α1-antitrypsin aggregates, as well as p62 bodies and condensates. p62 also acts as an intracellular signaling hub, and it involves multiple

JSI-124 inhibits cell proliferation and tumor growth by inducing autophagy and apoptosis in murine malignant mesothelioma.

Malignant pleural mesothelioma (MPM), mainly caused by asbestos exposure, has a poor prognosis and lacks effective treatment compared with other cancer types. The intracellular transcription factor signal transducer and activator of transcription 3 (STAT3) is overexpressed and hyperactivated in most human cancers. In this study, the role of STAT3 in murine MPM was examined. Inhibition of the Janus kinase 2 (JAK2)/STAT3 pathway with the selective inhibitor JSI-124 has an antitumor effect in murine MPM. Specifically, we demonstrated that JSI-124 inhibits murine MPM cell growth and induces apopto

Molecular Mechanism of Autophagy and Its Regulation by Cannabinoids in Cancer.

Autophagy is a "self-degradation" process whereby malfunctioned cytoplasmic constituents and protein aggregates are engulfed by a vesicle called the autophagosome, and subsequently degraded by the lysosome. Autophagy plays a crucial role in sustaining protein homeostasis and can be an alternative source of energy under detrimental circumstances. Studies have demonstrated a paradoxical function for autophagy in cancer, displaying both tumour suppressive and tumour promotive roles. In early phases of tumour development autophagy promotes cancer cell death. In later phases, autophagy enables canc

Совпадение в полном тексте источника
… LC3B-II was reported to be localized at both the inner and outer autophagosome membranes and, hence, LC3B-II is known as a specific and reliable marker for the autophagosome [ 19 ]. … In mammalian structures STX17, the autophagosomal Q-SNARE, is employed from the mitochondria and endoplasmic reticulum (ER) to completed autophagosomes when autophagy is induced [ 25 ]. …

The inducible amphisome isolates viral hemagglutinin and defends against influenza A virus infection.

The emergence of drug-resistant influenza type A viruses (IAVs) necessitates the development of novel anti-IAV agents. Here, we target the IAV hemagglutinin (HA) protein using multivalent peptide library screens and identify PVF-tet, a peptide-based HA inhibitor. PVF-tet inhibits IAV cytopathicity and propagation in cells by binding to newly synthesized HA, rather than to the HA of the parental virus, thus inducing the accumulation of HA within a unique structure, the inducible amphisome, whose production from the autophagosome is accelerated by PVF-tet. The amphisome is also produced in respo

Algal Autophagy Is Necessary for the Regulation of Carbon Metabolism Under Nutrient Deficiency.

Autophagy is a mechanism to recycle intracellular constituents such as amino acids and other carbon- and nitrogen (N)-containing compounds. Although autophagy-related (ATG) genes required for autophagy are encoded by many algal genomes, their functional importance in microalgae in nutrient-deficiency has not been appraised using ATG-defective mutants. Recently, by characterization of an insertional mutant of the ATG8 encoding a ubiquitin-like protein indispensable for autophagosome formation in a green alga Chlamydomonas reinhardtii, we have provided evidence that supports the following notion

Hepatitis C virus nonstructural 5A protein inhibits the starvation‑induced apoptosis of hepatoblastoma cells by increasing Beclin 1 expression.

Hepatitis C virus (HCV) nonstructural protein 5A (NS5A) modulates cellular apoptosis, which is involved in the occurrence and development of liver cancer. The mechanisms of apoptosis inhibition by NS5A in liver cancer cells remains unclear. Beclin 1, which functions upstream of autophagosome formation, is upregulated by NS5A. Autophagy, an evolutionarily conserved catabolic process, has a crucial role in tumor initiation and progression. Autophagy was blocked by inhibitors 3‑methyladenine and chloroquine, or via knockdown of Beclin 1. Flow cytometric analysis and western blotting were used to

Phosphoinositides in autophagy: current roles and future insights.

Today, the importance of autophagy in physiological processes and pathological conditions is undeniable. Initially, autophagy merely was described as an evolutionarily conserved mechanism to maintain metabolic homeostasis in times of starvation; however, in recent years it is now apparent that autophagy is a powerful regulator of many facets of cellular metabolism, that its deregulation contributes to various human pathologies, including cancer and neurodegeneration, and that its modulation has considerable potential as a therapeutic approach. Different lipid species, including sphingolipids,

Overactive autophagy is a pathological mechanism underlying premature suture ossification in nonsyndromic craniosynostosis.

Nonsyndromic craniosynostosis (NSC) is the most common craniosynostosis with the primary defect being one or more fused sutures. In contrast to syndromic craniosynostosis, the etiopathogenesis of NSC is largely unknown. Here we show that autophagy, a major catabolic process required for the maintenance of bone homeostasis and bone growth, is a pathological change associated with NSC. Using calvarial suture mesenchymal cells (SMCs) isolated from the fused and unfused sutures of NSC patients, we demonstrate that during SMC differentiation, the level of the autophagosomal marker LC3-II increases

Involvement of Beclin‑1 in axonal protection by short‑term hyperglycemia against TNF‑induced optic nerve damage.

Beclin‑1 serves a pivotal role in autophagosome formation. A previous study demonstrated that streptozotocin‑induced hyperglycemia (HG) ameliorates axonal loss induced by tumor necrosis factor (TNF) with upregulation of autophagy in rats. The aim of present study was to examine whether Beclin‑1 is involved in this autophagy machinery. Immunoblot analysis of optic nerves demonstrated that HG upregulated Beclin‑1 protein expression when compared with normoglycemia (NG). Intravitreal administration of TNF did not alter the optic nerve Beclin‑1 expression in NG nor in HG. Beclin‑1 immunoreactivity

GOLGA2 loss causes fibrosis with autophagy in the mouse lung and liver.

Autophagy is a biological recycling process via the self-digestion of organelles, proteins, and lipids for energy-consuming differentiation and homeostasis. The Golgi serves as a donor of the double-membraned phagophore for autophagosome assembly. In addition, recent studies have demonstrated that pulmonary and hepatic fibrosis is accompanied by autophagy. However, the relationships among Golgi function, autophagy, and fibrosis are unclear. Here, we show that the deletion of GOLGA2, encoding a cis-Golgi protein, induces autophagy with Golgi disruption. The induction of autophagy leads to fibro

IRF8 directs stress-induced autophagy in macrophages and promotes clearance of Listeria monocytogenes.

Autophagy, activated by many stresses, plays a critical role in innate immune responses. Here we show that interferon regulatory factor 8 (IRF8) is required for the expression of autophagy-related genes in dendritic cells. Furthermore in macrophages, IRF8 is induced by multiple autophagy-inducing stresses, including IFNγ and Toll-like receptor stimulation, bacterial infection, starvation and by macrophage colony-stimulating factor. IRF8 directly activates many genes involved in various steps of autophagy, promoting autophagosome formation and lysosomal fusion. Consequently, Irf8(-/-) macrophag

Measuring autophagy in stressed cells.

Macro-autophagy is a major catabolic process in the cell used to degrade protein aggregates, dysfunctional organelles and intracellular pathogens that would otherwise become toxic. Autophagy also generates energy and metabolites for the cell through recycling of degraded autophagosomal cargo, which can be particularly important for cell viability under stress. The significance of changes in the rates of autophagic flux for cellular function and disease is being increasingly appreciated, and interest in measuring autophagy in different experimental systems is growing accordingly. Here, we descr

The cardioprotective compound cloxyquin uncouples mitochondria and induces autophagy.

Mitochondrial quality control mechanisms have been implicated in protection against cardiac ischemia-reperfusion (IR) injury. Previously, cloxyquin (5-chloroquinolin-8-ol) was identified via phenotypic screening as a cardioprotective compound. Herein, cloxyquin was identified as a mitochondrial uncoupler in both isolated heart mitochondria and adult cardiomyocytes. Additionally, cardiomyocytes isolated from transgenic mice expressing green fluorescent protein-tagged microtubule-associated protein light chain 3 showed increased autophagosome formation with cloxyquin treatment. The autophagy inh

RUN and FYVE domain-containing protein 4 enhances autophagy and lysosome tethering in response to Interleukin-4.

Autophagy is a key degradative pathway coordinated by external cues, including starvation, oxidative stress, or pathogen detection. Rare are the molecules known to contribute mechanistically to the regulation of autophagy and expressed specifically in particular environmental contexts or in distinct cell types. Here, we unravel the role of RUN and FYVE domain-containing protein 4 (RUFY4) as a positive molecular regulator of macroautophagy in primary dendritic cells (DCs). We show that exposure to interleukin-4 (IL-4) during DC differentiation enhances autophagy flux through mTORC1 regulation a

The influence of age on apoptotic and other mechanisms of cell death after cerebral hypoxia-ischemia.

Unilateral hypoxia-ischemia (HI) was induced in C57/BL6 male mice on postnatal day (P) 5, 9, 21 and 60, corresponding developmentally to premature, term, juvenile and adult human brains, respectively. HI duration was adjusted to obtain a similar extent of brain injury at all ages. Apoptotic mechanisms (nuclear translocation of apoptosis-inducing factor, cytochrome c release and caspase-3 activation) were several-fold more pronounced in immature than in juvenile and adult brains. Necrosis-related calpain activation was similar at all ages. The CA1 subfield shifted from apoptosis-related neurona

MAP2K6 directly phosphorylates BCL2L13 to mediate mitophagy for suppressing tumorigenicity.

The mitogen-activated protein kinase (MAPK) pathway widely regulates development and cancer. However, the subcellular localization and function of the secondary kinases in the MAPK pathway remain unclear. Here, we identified mitogen-activated protein kinase kinase 6 or 3 (MKK6/MKK3) as tumor suppressors that could significantly activate mitophagy and suppress tumor growth in lung adenocarcinoma (LUAD). Mechanistically, among MKK1-7, only MKK6/MKK3 exhibited subcellular organellar localization in mitochondria and autophagosome interaction site. The function of MKK6 in mitophagy and tumorigenici

Zinc exacerbates tau-induced neuronal damage and autophagy dysfunction by inhibiting the Akt/mTOR pathway.

Alzheimer's disease (AD) is a multifactorial neurodegenerative disorder in which tau pathology correlates more strongly with clinical progression than amyloid-β (Aβ). Zinc (Zn²⁺) is known to promote tau-mediated neurotoxicity; however, the underlying mechanisms remain incompletely understood. Our previous work demonstrated that Zinc ions (Zn²⁺) binds to the third microtubule-binding repeat (R3) of tau, inducing oligomerization and enhancing neurotoxicity. Here, we demonstrated that Zn²⁺+R3 elevated phosphorylated tau (p-tau) levels, impaired dendritic spine morphology, reduced synaptophysin ex

Vacuolar protein sorting 4B is a novel regulator of osteoblast and adipocyte differentiation by activating autophagy signaling.

Vacuolar protein sorting 4B (VPS4B) is part of the endosomal sorting complex required for the transport machinery and is essential for autophagosome completion. Vps4b mutation might reduce the ability of dental follicle cells to differentiate during the mineralization process. However, the role of VPS4B in osteogenic and adipogenic differentiation from mesenchymal stem/progenitor cells remains to be explored. In the present study, we observed a substantial presence of VPS4B in bone, as well as an increase in its expression levels during the osteogenic and adipogenic differentiation of mesenchy

Proteasomal Degradation of Mutant Huntingtin Exon1 Regulates Autophagy.

Accumulation of misfolded proteins is implicated in neurodegenerative diseases. One of these is Huntington's disease, which is caused by an expansion of trinucleotide (CAG) repeats in exon 1 of huntingtin gene (HTT). This expansion results in the production of mutant huntingtin exon1 protein (mHttEx1) containing polyglutamine tracks that is prone to cytotoxic aggregation. These mHttEx1 aggregates range from small soluble aggregates to large insoluble inclusion bodies. The mechanisms to clear mHttEx1 aggregates include ubiquitin-dependent proteasomal degradation and autophagy. For the proteasom