scholarly journals Autophagosome maturation: An epic journey from the ER to lysosomes

2018 ◽  
Vol 218 (3) ◽  
pp. 757-770 ◽  
Author(s):  
Yan G. Zhao ◽  
Hong Zhang

Macroautophagy involves the sequestration of cytoplasmic contents in a double-membrane autophagosome and their delivery to lysosomes for degradation. In multicellular organisms, nascent autophagosomes fuse with vesicles originating from endolysosomal compartments before forming degradative autolysosomes, a process known as autophagosome maturation. ATG8 family members, tethering factors, Rab GTPases, and SNARE proteins act coordinately to mediate fusion of autophagosomes with endolysosomal vesicles. The machinery mediating autophagosome maturation is under spatiotemporal control and provides regulatory nodes to integrate nutrient availability with autophagy activity. Dysfunction of autophagosome maturation is associated with various human diseases, including neurodegenerative diseases, Vici syndrome, cancer, and lysosomal storage disorders. Understanding the molecular mechanisms underlying autophagosome maturation will provide new insights into the pathogenesis and treatment of these diseases.

Cells ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 979 ◽  
Author(s):  
Valeria De Pasquale ◽  
Anna Moles ◽  
Luigi Michele Pavone

Cathepsins (CTSs) are ubiquitously expressed proteases normally found in the endolysosomal compartment where they mediate protein degradation and turnover. However, CTSs are also found in the cytoplasm, nucleus, and extracellular matrix where they actively participate in cell signaling, protein processing, and trafficking through the plasma and nuclear membranes and between intracellular organelles. Dysregulation in CTS expression and/or activity disrupts cellular homeostasis, thus contributing to many human diseases, including inflammatory and cardiovascular diseases, neurodegenerative disorders, diabetes, obesity, cancer, kidney dysfunction, and others. This review aimed to highlight the involvement of CTSs in inherited lysosomal storage disorders, with a primary focus to the emerging evidence on the role of CTSs in the pathophysiology of Mucopolysaccharidoses (MPSs). These latter diseases are characterized by severe neurological, skeletal and cardiovascular phenotypes, and no effective cure exists to date. The advance in the knowledge of the molecular mechanisms underlying the activity of CTSs in MPSs may open a new challenge for the development of novel therapeutic approaches for the cure of such intractable diseases.


Author(s):  
Gustavo H. B. Maegawa

The lysosomal storage disorders (LSDs) are a group of inborn organelle disorders, clinically heterogeneous, and biochemically characterized by accumulation of nondegraded macromolecules primarily in the lysosomal and other cellular compartments. Given the common and essential cellular function of the lysosomal system in different organs and systems, patients afflicted with these disorders present a broad range of clinical problems, including neurological problems, visceromegaly, and skeletal deformities. Onset of symptoms may range from fetal period to adulthood. The neurological problems include developmental delay, seizures, acroparesthesia, motor weakness, muscle wasting, behavioral/psychiatric disturbances, cerebrovascular ischemic events, and extrapyramidal signs. Patients may present with symptoms later that include psychiatric manifestations, are slowly progressive, and may precede other neurologic or systemic features. Most of LSDs are autosomal recessive; however, a few are X-linked with symptpmatic female carriers (e.g., Fabry disease). In most of them, the diagnosis is established by biochemical and/or molecular assays. In terms of management, disease-modifying therapies include enzyme replacement, hematopoietic stem cell transplantation, and substrate reduction therapy. Patients and their families require genetic counseling regarding reproductive risks, disease prognosis, and therapeutic options. Investigations of disease molecular mechanisms provide insights into potential targets for the development of therapeutic strategies. Supportive care has been the key and essential for most LSDs, resulting in substantial improvement in quality of life of patients and families.


Author(s):  
Daniel Erskine ◽  
David Koss ◽  
Viktor I. Korolchuk ◽  
Tiago F. Outeiro ◽  
Johannes Attems ◽  
...  

AbstractAccumulation of the protein α-synuclein into insoluble intracellular deposits termed Lewy bodies (LBs) is the characteristic neuropathological feature of LB diseases, such as Parkinson’s disease (PD), Parkinson’s disease dementia (PDD) and dementia with LB (DLB). α-Synuclein aggregation is thought to be a critical pathogenic event in the aetiology of LB disease, based on genetic analyses, fundamental studies using model systems, and the observation of LB pathology in post-mortem tissue. However, some monogenic disorders not traditionally characterised as synucleinopathies, such as lysosomal storage disorders, iron storage disorders and mitochondrial diseases, appear disproportionately vulnerable to the deposition of LBs, perhaps suggesting the process of LB formation may be a result of processes perturbed as a result of these conditions. The present review discusses biological pathways common to monogenic disorders associated with LB formation, identifying catabolic processes, particularly related to lipid homeostasis, autophagy and mitochondrial function, as processes that could contribute to LB formation. These findings are discussed in the context of known mediators of α-synuclein aggregation, highlighting the potential influence of impairments to these processes in the aetiology of LB formation.


2021 ◽  
Author(s):  
Maurizio Pieroni ◽  
Federico Pieruzzi ◽  
Renzo Mignani ◽  
Francesca Graziani ◽  
Iacopo Olivotto ◽  
...  

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Maria De Risi ◽  
Michele Tufano ◽  
Filomena Grazia Alvino ◽  
Maria Grazia Ferraro ◽  
Giulia Torromino ◽  
...  

AbstractLysosomal storage disorders characterized by altered metabolism of heparan sulfate, including Mucopolysaccharidosis (MPS) III and MPS-II, exhibit lysosomal dysfunctions leading to neurodegeneration and dementia in children. In lysosomal storage disorders, dementia is preceded by severe and therapy-resistant autistic-like symptoms of unknown cause. Using mouse and cellular models of MPS-IIIA, we discovered that autistic-like behaviours are due to increased proliferation of mesencephalic dopamine neurons originating during embryogenesis, which is not due to lysosomal dysfunction, but to altered HS function. Hyperdopaminergia and autistic-like behaviours are corrected by the dopamine D1-like receptor antagonist SCH-23390, providing a potential alternative strategy to the D2-like antagonist haloperidol that has only minimal therapeutic effects in MPS-IIIA. These findings identify embryonic dopaminergic neurodevelopmental defects due to altered function of HS leading to autistic-like behaviours in MPS-II and MPS-IIIA and support evidence showing that altered HS-related gene function is causative of autism.


2021 ◽  
Vol 7 (18) ◽  
pp. eabc6266
Author(s):  
Qi Li ◽  
Ningkun Liu ◽  
Qing Liu ◽  
Xingguo Zheng ◽  
Lu Lu ◽  
...  

Eukaryotic cells contain numerous membraneless organelles that are made from liquid droplets of proteins and nucleic acids and that provide spatiotemporal control of various cellular processes. However, the molecular mechanisms underlying the formation and rapid stress-induced alterations of these organelles are relatively uncharacterized. Here, we investigated the roles of DEAD-box helicases in the formation and alteration of membraneless nuclear dicing bodies (D-bodies) in Arabidopsis thaliana. We uncovered that RNA helicase 6 (RH6), RH8, and RH12 are previously unidentified D-body components. These helicases interact with and promote the phase separation of SERRATE, a key component of D-bodies, and drive the formation of D-bodies through liquid-liquid phase separations (LLPSs). The accumulation of these helicases in the nuclei decreases upon Turnip mosaic virus infections, which couples with the decrease of D-bodies. Our results thus reveal the key roles of RH6, RH8, and RH12 in modulating D-body formation via LLPSs.


2021 ◽  
Author(s):  
Neel S. Iyer ◽  
Alexis C. Gimovsky ◽  
Carlos R. Ferreira ◽  
Elizabeth J. Critchlow ◽  
Huda B. Al‐kouatly

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Atul Mehta ◽  
Uma Ramaswami ◽  
Joseph Muenzer ◽  
Roberto Giugliani ◽  
Kurt Ullrich ◽  
...  

Abstract Background Lysosomal storage disorders (LSDs) are rare genetic disorders, with heterogeneous clinical manifestations and severity. Treatment options, such as enzyme replacement therapy (ERT), substrate replacement therapy, and pharmacological chaperone therapy, are available for several LSDs, including Gaucher disease (GD), Fabry disease (FD), and Hunter syndrome (mucopolysaccharidosis type II [MPS II]). However, patients in some countries face challenges accessing treatments owing to limited availability of locally licensed, approved drugs. Methods The Takeda LSD Charitable access program aims to meet the needs of individuals with GD, FD or MPS II with the greatest overall likelihood of benefit, in selected countries, through donation of ERT to nonprofit organizations, and support for medical capacity-building as well as family support via independent grants. Long-term aims of the program are to establish sustainable healthcare services delivered by local healthcare providers for patients with rare metabolic diseases. Patients receiving treatment through the program are monitored regularly, and their clinical data and progress are reviewed annually by an independent medical expert committee (MEC). The MEC also selects patients for enrollment completely independent from the sponsoring company. Results As of 31 August, 2019, 199 patients from 13 countries were enrolled in the program; 142 with GD, 41 with MPS II, and 16 with FD. Physicians reported improvements in clinical condition for 147 (95%) of 155 patients with follow-up data at 1 year. Conclusions The response rate for follow-up data at 1 year was high, with data collected for > 90% of patients who received ERT through the program showing clinical improvements in the majority of patients. These findings suggest that the program can benefit selected patients previously unable to access disease-specific treatments. Further innovative solutions and efforts are needed to address the challenges and unmet needs of patients with LSDs and other rare diseases around the world.


Sign in / Sign up

Export Citation Format

Share Document