SKA2 regulated hyperactive secretory autophagy drives neuroinflammation-induced neurodegeneration
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE181203 | GEO | 2024/02/26
REPOSITORIES: GEO
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Project description:SKA2 regulated hyperactive secretory autophagy drives neuroinflammation-induced neurodegeneration
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Project description:High levels of proinflammatory cytokines induce neurotoxicity and catalyze inflammation-driven neurodegeneration, but the specific release mechanisms from microglia remain elusive. Here we show that secretory autophagy (SA), a non-lytic modality of autophagy for secretion of vesicular cargo, regulates neuroinflammation-mediated neurodegeneration via SKA2 and FKBP5 signaling. SKA2 inhibits SA-dependent IL-1β release by counteracting FKBP5 function. Hippocampal Ska2 knockdown in male mice hyperactivates SA resulting in neuroinflammation, subsequent neurodegeneration and complete hippocampal atrophy within six weeks. The hyperactivation of SA increases IL-1β release, contributing to an inflammatory feed-forward vicious cycle including NLRP3-inflammasome activation and Gasdermin D-mediated neurotoxicity, which ultimately drives neurodegeneration. Results from protein expression and co-immunoprecipitation analyses of male and female postmortem human brains demonstrate that SA is hyperactivated in Alzheimer's disease. Overall, our findings suggest that SKA2-regulated, hyperactive SA facilitates neuroinflammation and is linked to Alzheimer's disease, providing mechanistic insight into the biology of neuroinflammation.
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Project description:Protein synthesis and autophagic degradation are regulated in an opposite manner by mammalian target of rapamycin (mTOR), whereas under certain conditions it would be beneficial if they occured in unison to handle rapid protein turnover. We observed a distinct cellular compartment at the trans-side of the Golgi apparatus, the ‘TOR-autophagy spatial coupling compartment’ (TASCC), where (auto)lysosomes and mTOR accumulated during Ras-induced senescence. mTOR recruitment to the TASCC was amino acid- and Rag guanosine triphosphatase (GTPase)-dependent, and disruption of mTOR localization to the TASCC suppressed interleukin-6/8 synthesis. TASCC-formation was observed during macrophage differentiation and in glomerular podocytes; both displayed increased protein secretion. The spatial coupling of cells’ catabolic and anabolic machinery could augment their respective functions and facilitate the mass synthesis of secretory proteins. To compare gene expression profile between growing and oncogenic Ras induced senescence, 4OHT inducible ER:H-RasV12 was stably expressed in IMR90 human diploid fibroblasts. Total RNA was isolated from day 0 and day 4 after 4OHT addition. There were 3 biological replicates for each of day0 and day 4 timepoints.
2011-05-04 | E-GEOD-28464 | biostudies-arrayexpress
Project description:Increasing evidence suggests an essential function for autophagy in unconventional protein secretion (UPS). However, despite its relevance for the secretion of aggregate-prone proteins, the mechanisms of secretory autophagy in neurons have remained elusive. Here we show that the lower motoneuron disease-associated protein Plekhg5 drives the UPS of Sod1. Mechanistically, Sod1 is sequestered into the intermembrane space of autophagosomes which fuse with secretory lysosomal-related organelles (LROs). Deletion of Plekhg5 in mice disrupts the secretion of these LROs causing Sod1 accumulation at swollen presynaptic sites. A reduced secretion of toxic ALS-linked SOD1G93A following deletion of Plekhg5 in SOD1G93A mice accelerated disease onset while prolonging survival due to an attenuated microglia activation. Using human isogenic iPSC-derived motoneurons we show an impaired secretion of ALS-linked SOD1D90A, which coincided with a reduced PLEKHG5 expression. Our findings highlight an unexpected pathophysiological mechanism that converges two motoneuron disease-associated proteins into a common pathway.
2024-08-28 | GSE269588 | GEO
Project description:Plekhg5 regulates the unconventional secretion of Sod1 by presynaptic secretory autophagy
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Project description:Protein synthesis and autophagic degradation are regulated in an opposite manner by mammalian target of rapamycin (mTOR), whereas under certain conditions it would be beneficial if they occured in unison to handle rapid protein turnover. We observed a distinct cellular compartment at the trans-side of the Golgi apparatus, the ‘TOR-autophagy spatial coupling compartment’ (TASCC), where (auto)lysosomes and mTOR accumulated during Ras-induced senescence. mTOR recruitment to the TASCC was amino acid- and Rag guanosine triphosphatase (GTPase)-dependent, and disruption of mTOR localization to the TASCC suppressed interleukin-6/8 synthesis. TASCC-formation was observed during macrophage differentiation and in glomerular podocytes; both displayed increased protein secretion. The spatial coupling of cells’ catabolic and anabolic machinery could augment their respective functions and facilitate the mass synthesis of secretory proteins.
2011-05-05 | GSE28464 | GEO
Project description:Stress response is a fundamental mechanism to maintain a healthy homeostasis and its disruption is implicated in several psychiatric disorders. Autophagy is one of the mechanisms regulating homeostasis, and it is known to be activated by cellular stressors such as starvation. In a previous study, we revealed that glucocorticoid (GC)-mediated stress also activates macroautophagy via the stress-responsive co-chaperone FK506-binding protein 51 (FKBP51). In this study we reveal that GC-mediated stress enhances secretory autophagy, a recently described Atg-dependent secretory pathway, via FKBP51. Strikingly we detected the matrix metallopeptidase 9 (Mmp9) as one of the stress-induced secreted proteins. Furthermore we found that enhanced Mmp9 secretion increases both in vitro and in vivo the cleavage of pro-brain derived neurotrophic factor (proBdnf) to its mature form (mBdnf), a key protein in neuroplasticity. This unravelled mechanism can represent a link between stress and the development of psychiatric disorders.
2021-08-05 | PXD017076 | Pride
Project description:Stress response is a fundamental mechanism to maintain a healthy homeostasis and its disruption is implicated in several psychiatric disorders. Autophagy is one of the mechanisms regulating homeostasis, and it is known to be activated by cellular stressors such as starvation. In a previous study, we revealed that glucocorticoid (GC)-mediated stress also activates macroautophagy via the stress-responsive co-chaperone FK506-binding protein 51 (FKBP51). In this study we reveal that GC-mediated stress enhances secretory autophagy, a recently described Atg-dependent secretory pathway, via FKBP51. Strikingly we detected the matrix metallopeptidase 9 (Mmp9) as one of the stress-induced secreted proteins. Furthermore we found that enhanced Mmp9 secretion increases both in vitro and in vivo the cleavage of pro-brain derived neurotrophic factor (proBdnf) to its mature form (mBdnf), a key protein in neuroplasticity. This unravelled mechanism can represent a link between stress and the development of psychiatric disorders.
2021-08-25 | PXD017328 | Pride
Project description:Autophagy is a recycling program for cells to adapt to metabolic needs and to stress. Defects in autophagy can affect metabolism, aging, proteostasis and inflammation. We used microarrays to determine the changes in global gene expression in murine melanocyte upon genetic inactivation of the essential autophagy gene Atg7 and as secondary aim wheter the gene regulation by ultraviolet A light is affected by the Atg7 knockout
2019-06-29 | GSE83856 | GEO
Project description:Neuroinflammation and neurodegeneration are key components in the establishment and progression of neurodegenerative diseases including Alzheimer's Disease (AD). Over the past decade increasing evidence is emerging for the use of components of the canonical autophagy machinery in pathways that are characterized by LC3 lipidation yet are distinct from traditional macro-autophagy. One such pathway that utilizes components of the autophagy machinery to target LC3 to endosomes, a process termed LC3-associated endocytosis (LANDO), has recently been identified and regulates neuroinflammation. Abrogation of LANDO in microglia cells results in a propensity for elevated neuroinflammatory cytokine production. Using the well-established 5xFAD model of AD to interrogate neuroinflammatory regulation, impairment of LANDO through deletion of a key upstream regulator Rubicon or other downstream autophagy components, exacerbated disease onset and severity, while deletion of microglial autophagy alone had no measurable effect. Mice presented with robust deposition of the neurotoxic AD protein β-amyloid (Aβ), microglial activation and inflammatory cytokine production, tau phosphorylation, and aggressive neurodegeneration culminating in severe memory impairment. LANDO-deficiency impaired recycling of receptors that recognize Aβ, including TLR4 and TREM2. LANDO-deficiency alone through deletion of the WD-domain of the autophagy protein ATG16L, revealed a role for LANDO in the spontaneous establishment of age-associated AD. LANDO-deficient mice aged to 2 years presented with advanced AD-like disease and pathology correlative to that observed in human AD patients. Together, these studies illustrate an important role for microglial LANDO in regulating CNS immune activation and protection against neurodegeneration. New evidence is emerging that demonstrates a putative linkage between pathways such as LANDO and cell death regulation via apoptosis and possibly necroptosis. Herein, we provide a review of the use of the autophagy machinery in non-canonical mechanisms that alter immune regulation and could have significant impact in furthering our understanding of not only CNS diseases like AD, but likely beyond.
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