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Journal of Molecular and Cellular... Aug 2020Deubiquitinating enzymes (DUBs) appear to be a new class of regulators of cardiac homeostasis and disease. However, DUB-mediated signaling in the heart is not well...
Deubiquitinating enzymes (DUBs) appear to be a new class of regulators of cardiac homeostasis and disease. However, DUB-mediated signaling in the heart is not well understood. Herein we report a novel mechanism by which cylindromatosis (CYLD), a DUB mediates cardiac pathological remodeling and dysfunction. Cardiomyocyte-restricted (CR) overexpression of CYLD (CR-CYLD) did not cause gross health issues and hardly affected cardiac function up to age of one year in both female and male mice at physiological conditions. However, CR-CYLD overexpression exacerbated pressure overload (PO)-induced cardiac dysfunction associated with suppressed cardiac hypertrophy and increased myocardial apoptosis in mice independent of the gender. At the molecular level, CR-CYLD overexpression enhanced PO-induced increases in poly-ubiquitinated proteins marked by lysine (K)48-linked ubiquitin chains and autophagic vacuoles containing undegraded contents while suppressing autophagic flux. Augmentation of cardiac autophagy via CR-ATG7 overexpression protected against PO-induced cardiac pathological remodeling and dysfunction in both female and male mice. Intriguingly, CR-CYLD overexpression switched the CR-ATG7 overexpression-dependent cardiac protection into myocardial damage and dysfunction associated with increased accumulation of autophagic vacuoles containing undegraded contents in the heart. Genetic manipulation of Cyld in combination with pharmacological modulation of autophagic functional status revealed that CYLD suppressed autolysosomal degradation and promoted cell death in cardiomyocytes. In addition, Cyld gene gain- and/or loss-of-function approaches in vitro and in vivo demonstrated that CYLD mediated cardiomyocyte death associated with impaired reactivation of mechanistic target of rapamycin complex 1 (mTORC1) and upregulated Ras genes from rat brain 7 (Rab7), two key components for autolysosomal degradation. These results demonstrate that CYLD serves as a novel mediator of cardiac pathological remodeling and dysfunction by suppressing autolysosome efflux in cardiomyocytes. Mechanistically, it is most likely that CYLD suppresses autolysosome efflux via impairing mTORC1 reactivation and interrupting Rab7 release from autolysosomes in cardiomyocytes.
Topics: Animals; Autophagy; Autophagy-Related Protein 7; Brain; Cardiomyopathies; Deubiquitinating Enzyme CYLD; Fibroblasts; Genes, ras; Lysine; Lysosomes; Male; Mechanistic Target of Rapamycin Complex 1; Mice, Transgenic; Myocardium; Myocytes, Cardiac; Pressure; Rats; Ubiquitination; Up-Regulation; Vacuoles
PubMed: 32553594
DOI: 10.1016/j.yjmcc.2020.06.004 -
Autophagy 2018Macroautophagy/autophagy is a proteolytic pathway that is involved in both bulk degradation of cytoplasmic proteins as well as in selective degradation of cytoplasmic...
UNLABELLED
Macroautophagy/autophagy is a proteolytic pathway that is involved in both bulk degradation of cytoplasmic proteins as well as in selective degradation of cytoplasmic organelles. Autophagic flux is often defined as a measure of autophagic degradation activity, and many techniques exist to assess autophagic flux. Although these techniques have generated invaluable information about the autophagic system, the quest continues for developing methods that not only enhance sensitivity and provide a means of quantification, but also accurately reflect the dynamic character of the pathway. Based on the theoretical framework of metabolic control analysis, where the autophagosome flux is the quantitative description of the rate a flow along a pathway, here we treat the autophagy system as a multi-step pathway. We describe a single-cell fluorescence live-cell imaging-based approach that allows the autophagosome flux to be accurately measured. This method characterizes autophagy in terms of its complete autophagosome and autolysosome pool size, the autophagosome flux, J, and the transition time, τ, for autophagosomes and autolysosomes at steady state. This approach provides a sensitive quantitative method to measure autophagosome flux, pool sizes and transition time in cells and tissues of clinical relevance.
ABBREVIATIONS
ATG5/APG5, autophagy-related 5; GFP, green fluorescent protein; LAMP1, lysosomal-associated membrane protein 1; MAP1LC3/LC3, microtubule-associated protein 1 light chain 3; J, flux; MEF, mouse embryonic fibroblast; MTOR, mechanistic target of rapamycin kinase; nA, number of autophagosomes; nAL, number of autolysosomes; nL, number of lysosomes; p-MTOR, phosphorylated mechanistic target of rapamycin kinase; RFP, red fluorescent protein; siRNA, small interfering RNA; τ, transition time; TEM, transmission electron microscopy.
Topics: Animals; Autophagosomes; Cell Survival; Image Processing, Computer-Assisted; Lysosomes; Mice; Microscopy, Fluorescence; Single-Cell Analysis; Sirolimus; Time Factors
PubMed: 29909716
DOI: 10.1080/15548627.2018.1469590 -
Autophagy Jun 2022STX17 (syntaxin 17) mediates autophagosome-lysosome fusion, and the translocation of STX17 to autophagosomes is characteristic of this process. STX17 arrives at...
STX17 (syntaxin 17) mediates autophagosome-lysosome fusion, and the translocation of STX17 to autophagosomes is characteristic of this process. STX17 arrives at autophagosomes when they are closed, stays there for approximately 10 min to promote fusion with lysosomes, and leaves when the autolysosomes are mature. However, the mechanism of this transient visit remains largely unknown. Here, we summarize the current knowledge about this phenomenon, including a recently discovered retrieval mechanism, and discuss remaining questions. MAM: mitochondria-associated membrane; SNX: sorting nexin; STX17: syntaxin 17.
Topics: Autophagosomes; Autophagy; Lysosomes; Membrane Fusion; Qa-SNARE Proteins
PubMed: 35613317
DOI: 10.1080/15548627.2022.2079337 -
Experimental Cell Research Jan 2013Autophagy is an evolutionarily conserved lysosome-dependent degradation pathway. In recent years, many important advances have been made in understanding the cellular... (Review)
Review
Autophagy is an evolutionarily conserved lysosome-dependent degradation pathway. In recent years, many important advances have been made in understanding the cellular and molecular mechanism of autophagosome formation. However, the late stages of autophagy-the cellular events after formation of the autolysosome-are relatively rarely studied. In this review, we discussed the cellular process and molecular mechanism of autophagic lysosome reformation, a cellular events which defines the terminal stage of autophagy.
Topics: Autophagy; Humans; Lysosomes; TOR Serine-Threonine Kinases
PubMed: 22999865
DOI: 10.1016/j.yexcr.2012.09.004 -
Journal of Cellular and Molecular... Feb 2023Lysosomes, a central regulator of autophagy, play a critical role in tumour growth. Lysosomal protease cathepsin D can initiate apoptosis when released from lysosomes...
Lysosomes, a central regulator of autophagy, play a critical role in tumour growth. Lysosomal protease cathepsin D can initiate apoptosis when released from lysosomes into the cytosol. In this study, we observed that Musca domestica cecropin (Mdc) 1-8 (M1-8), a small anti-tumour peptide derived from Mdc, inhibits hepatoma cell growth by blocking autophagy-lysosome fusion. This effect is likely achieved by targeting lysosomes to activate lysosomal protease D. Additionally, we examined whether lysosomal content and cathepsin D release were involved in M1-8-induced apoptosis. After exposure to M1-8, human hepatoma HepG2 cells rapidly co-localized with lysosomes, disrupted lysosomal integrity, caused leakage of lysosomal protease cathepsin D, caspase activation and mitochondrial membrane potential changes; and promoted cell apoptosis. Interestingly, in M1-8-treated HepG2 cells, autophagic protein content increased and the lysosome-autophagosome fusion was inhibited, suggesting that M1-8 can cause apoptosis through autophagy and lysosomes. This result indicates that a small accumulation of autophagy and autolysosome inhibition in cells can cause cell death. Taken together, these data suggest a novel insight into the regulatory mechanisms of M1-8 in autophagy and lysosomes, which may facilitate the development of M1-8 as a potential cancer therapeutic agent.
Topics: Humans; Cathepsin D; Carcinoma, Hepatocellular; Antimicrobial Peptides; Apoptosis; Autophagy; Liver Neoplasms; Lysosomes
PubMed: 36628597
DOI: 10.1111/jcmm.17644 -
Angewandte Chemie (International Ed. in... Oct 2020It is of great significance to track the platinum drugs in real time with super-resolution to elucidate their mechanism of action, such as their behavior and...
It is of great significance to track the platinum drugs in real time with super-resolution to elucidate their mechanism of action, such as their behavior and distribution in live cells. Such information is required for further drug development. However, it is always challenging to design platinum complexes suitable for such research. Herein, we design a luminescent building block (L) for metal complexes and a dinuclear platinum complex (Pt L) for super-resolution imaging. Because of its super-large Stokes shift and excellent photophysical properties, Pt L is capable of serving as an ideal candidate for super-resolution imaging with extremely low luminescence background and high photobleaching resistance. Moreover, upon light stimulation, a matter flux of Pt L escaping from autolysosomes to nucleus was observed, which represents a new transportation path. Utilizing the photoactivated escape properties, we can regulate the nuclear accessibility of Pt L form autolysosomes with photo-selectivity, which provides a new way to improve the targeting of platinum drugs.
Topics: A549 Cells; Biological Transport; Cell Nucleus; Color; HeLa Cells; Humans; Lysosomes; Microscopy, Fluorescence; Mitochondria; Platinum Compounds
PubMed: 32662563
DOI: 10.1002/anie.202007878 -
Postepy Higieny I Medycyny... May 2017Dane literaturowe z ostatnich lat jednoznacznie wskazują na udział lizosomów w programowanej śmierci komórki. Dysfunkcje lizosomów upośledzają fuzję... (Review)
Review
Dane literaturowe z ostatnich lat jednoznacznie wskazują na udział lizosomów w programowanej śmierci komórki. Dysfunkcje lizosomów upośledzają fuzję autofagosomów z lizosomami, co prowadzi do wakuolizacji cytoplazmy. Obecność wakuoli autofagalnych obładowanych uszkodzonymi organellami i nieprawidłowymi białkami jest cechą charakterystyczną wielu chorób neurodegeneracyjnych. Agregacja niezdegradowanego materiału zaburza homeostazę komórki powodując śmierć neuronu w wyniku apoptozy i/lub nekrozy. Ponadto indukowany kalpainami lub spowodowany mutacjami rozpad błony lizosomu uwalnia katepsyny, które indukują szlak śmierci komórki. W artykule przedstawiono mechanizm śmierci komórki nerwowej, łączący zaburzenie szlaku autofagalno-lizosomalnego z dysfunkcjami lizosomów, zwany lizosomalnym szlakiem śmierci neuronu.
Topics: Apoptosis; Autophagy; Humans; Lysosomes; Necrosis; Neurodegenerative Diseases
PubMed: 28513454
DOI: 10.5604/01.3001.0010.3814 -
Colloids and Surfaces. B, Biointerfaces Oct 2019Targeting modifications and smart responsiveness of nanomedicines can enable anticancer drugs to be selectively delivered to and controllably released in tumour cells or...
Targeting modifications and smart responsiveness of nanomedicines can enable anticancer drugs to be selectively delivered to and controllably released in tumour cells or tissues, which can reduce the treatment's toxicity and side effects. Good biocompatibility is crucial for the clinical application of any nanomedicine. In this study, a double-targeting molecule, an RGD peptide- and 4-(2-aminoethyl) morpholine-modified, doxorubicin (DOX)-loaded bovine serum albumin (BSA) nanomedicine, that can be controllably released by the high levels of autophagic lysosomes in tumour cells was developed. The size of the spherical BSA nanoparticles is approximately 60 nm. In vitro experiments indicated that the RGD peptide- and 4-(2-aminoethyl) morpholine-modified, DOX-loaded BSA nanomedicine has a better therapeutic effect than free DOX. In vivo experiments suggested that the BSA nanomedicine can successfully suppress the progression of PC9 xenograft tumours. This phenomenon may be attributable to the endocytosis of a relatively large amount of nanomedicine and the effective release of the loaded chemotherapeutic agent, as induced by high levels of autolysosomes. Collectively, the results of this study provide a smart approach for increasing therapeutic efficacy using a double-targeting molecule-modified BSA nanomedicine.
Topics: Animals; Antibiotics, Antineoplastic; Cell Line; Cell Line, Tumor; Cell Survival; Delayed-Action Preparations; Doxorubicin; Drug Carriers; Drug Compounding; Drug Liberation; Female; Humans; Lung Neoplasms; Lysosomes; Mice; Mice, Nude; Morpholines; Nanomedicine; Nanoparticles; Oligopeptides; Serum Albumin, Bovine; Tumor Burden; Xenograft Model Antitumor Assays
PubMed: 31301582
DOI: 10.1016/j.colsurfb.2019.06.055 -
European Journal of Biochemistry Dec 1983The first international symposium on lysosomes [1] was held in 1963 at the Ciba Foundation, under the chairmanship of Danielli and with the participation of a... (Review)
Review
The first international symposium on lysosomes [1] was held in 1963 at the Ciba Foundation, under the chairmanship of Danielli and with the participation of a prestigious membership. It is interesting to compare our present understanding of the properties and functions of lysosomes with what was known 20 years ago.
Topics: Animals; Biological Transport, Active; Cell Membrane; Endocytosis; Eukaryotic Cells; Lysosomes; Phagocytosis; Protein Binding; Protons
PubMed: 6319122
DOI: 10.1111/j.1432-1033.1983.tb07841.x -
Trends in Cell Biology Nov 2022Autophagy is a multistage, intracellular process. Here, we highlight a recently identified autophagosomal components recycling (ACR) stage and the recycler complex...
Autophagy is a multistage, intracellular process. Here, we highlight a recently identified autophagosomal components recycling (ACR) stage and the recycler complex (SNX4-SNX5-SNX17), which mediates recycling of autophagosomal outer membrane proteins on the autolysosome surface immediately following autophagosome-lysosome fusion. This discovery opens numerous research directions into the postfusion fate of autophagosomes.
Topics: Autophagosomes; Autophagy; Autophagy-Related Proteins; Humans; Lysosomes; Membrane Fusion; Qa-SNARE Proteins
PubMed: 35840484
DOI: 10.1016/j.tcb.2022.06.012