Stimulation of TLR3 triggers release of lysosomal ATP in astrocytes and epithelial cells that requires TRPML1 channels

Beckel, Jonathan M.; Gómez, Néstor; Lu, Wennan; Campagno, Keith E.; Nabet, Bardia; Albalawi, Farraj; Lim, Jason; Boesze‐Battaglia, Kathleen; Mitchell, Claire H.

doi:10.1038/s41598-018-23877-3

Cited by 36 publications

(36 citation statements)

References 68 publications

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“…ATP is a potent inducer of EV shedding in several cell types, including microglia and astrocytes (Bianco et al, 2005(Bianco et al, , 2009Takenouchi et al, 2015). In brain, ATP can be co-released from neurons with other neurotransmitters (Edwards, Gibb, & Colquhoun, 1992;Silinsky, Gerzanich, & Vanner, 1992;Sperlagh, Kittel, Lajtha, & Vizi, 1995), and from astrocytes in response to glutamate, mechanical stretch, activation of toll-like receptor 3, and glucocorticoids (Beckel et al, 2018;Guthrie et al, 1999;Koyanagi et al, 2016;Queiroz, Gebicke-Haerter, Schobert, Starke, & von Kügelgen, 1997;Xiong et al, 2018). Extracellular ATP signals by binding to P2 receptors that include ionotropic P2X (P2X1−7) and metabotropic P2Y receptors (P2Y1, 2, 4, 6, 11-14;reviewed in Burnstock, 2007).…”

Section: Adev-il-10mentioning

confidence: 99%

Stimulus‐dependent modifications in astrocyte‐derived extracellular vesicle cargo regulate neuronal excitability

Chaudhuri

Dasgheyb

DeVine

et al. 2019

Glia

107

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Extracellular vesicles have now emerged as key players in cell‐to‐cell communication. This is particularly important in the central nervous system, where glia–neuron cross‐talk helps maintain normal neuronal function. Astrocyte‐derived extracellular vesicles (ADEVs) secreted constitutively promote neurite outgrowth and neuronal survival. However, extracellular stimuli can alter the cargo and downstream functions of ADEVs. For example, ADEVs secreted in response to inflammation contain cargo microRNAs and proteins that reduce neurite outgrowth, neuronal firing, and promote neuronal apoptosis. We performed a comprehensive quantitative proteomic analysis to enumerate the proteomic cargo of ADEVs secreted in response to multiple stimuli. Rat primary astrocytes were stimulated with a trophic stimulus (adenosine triphosphate, ATP), an inflammatory stimulus (IL‐1β) or an anti‐inflammatory stimulus (IL10) and extracellular vesicles secreted within a 2 hr time frame were collected using sequential ultracentrifugation method. ADEVs secreted constitutively without exposure to any stimulus were used a control. A tandem mass tag‐based proteomic platform was used to identify and quantify proteins in the ADEVs. Ingenuity pathway analysis was performed to predict the downstream signaling events regulated by ADEVs. We found that in response to ATP or IL10, ADEVs contain a set of proteins that are involved in increasing neurite outgrowth, dendritic branching, regulation of synaptic transmission, and promoting neuronal survival. In contrast, ADEVs secreted in response to IL‐1β contain proteins that regulate peripheral immune response and immune cell trafficking to the central nervous system.

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Section: Adev-il-10mentioning

confidence: 99%

Stimulus‐dependent modifications in astrocyte‐derived extracellular vesicle cargo regulate neuronal excitability

Chaudhuri

Dasgheyb

DeVine

et al. 2019

Glia

107

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“…2g). These data indicate that MHCII-immunopositive organelles are lysosomes, which undergo Ca 2+ -dependent exocytosis in astrocytes [39][40][41][42][43][44].…”

Section: Mhcii Is Localized In Late Endosomes and Lysosomes Of Ifnγ-tmentioning

confidence: 67%

“…In a previous study by Vardjan et al [14], no release of fluorescent dextrans indicative of full lysosomal exocytosis was observed in IFNγ-treated astrocytes either at rest or after cell stimulation with 1 mM ATP [16], a stimulus that increases the intracellular concentration of free Ca 2+ ions [Ca 2+ ] i [73,75,76]. This is likely explained by a relatively short post-stimulation time during which potential secretion from cells was monitored [16], because lysosomal exocytosis was shown to occur with a significant delay after cell stimulation [40,41,43].…”

Section: Increased Reversible Exocytosis Of Larger Vesicles Indicatesmentioning

confidence: 99%

“…Next, we asked whether MHCII-positive late endo-/lysosomes are delivered toward the astrocyte plasmalemma, where they may undergo exo-/endocytosis [39][40][41][42][43][44]. Nontreated controls and IFNγ-treated cells were double labeled by CT-B, which stains plasmalemmal domains enriched in ganglioside monosialic acid (GM1) lipid rafts [47], and by anti-MHCII, which stains individual MHCII-positive vesicles.…”

Section: Mhcii-positive Organelles Constitute a Subpopulation Of Largmentioning

confidence: 99%

“…Modulation of either expression or function of Syt XI by IFNγ could well explain some of our findings. Secretory lysosomes in astrocytes also store and secret ATP [39,40,77,78]. An increase in extracellular ATP concentration represents a danger signal that can lead to increased damage to neurons, promote reactive gliosis, and recruit microglia to instigate a neuroinflammatory response [79].…”

Section: Increased Reversible Exocytosis Of Larger Vesicles Indicatesmentioning

confidence: 99%

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Exocytosis of large-diameter lysosomes mediates interferon γ-induced relocation of MHC class II molecules toward the surface of astrocytes

Božić

Verkhratsky

Zorec

et al. 2019

Cell. Mol. Life Sci.

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Astrocytes are the key homeostatic cells in the central nervous system; initiation of reactive astrogliosis contributes to neuroinflammation. Pro-inflammatory cytokine interferon γ (IFNγ) induces the expression of the major histocompatibility complex class II (MHCII) molecules, involved in antigen presentation in reactive astrocytes. The pathway for MHCII delivery to the astrocyte plasma membrane, where MHCII present antigens, is unknown. Rat astrocytes in culture and in organotypic slices were exposed to IFNγ to induce reactive astrogliosis. Astrocytes were probed with optophysiologic tools to investigate subcellular localization of immunolabeled MHCII, and with electrophysiology to characterize interactions of single vesicles with the plasmalemma. In culture and in organotypic slices, IFNγ augmented the astrocytic expression of MHCII, which prominently co-localized with lysosomal marker LAMP1-EGFP, modestly co-localized with Rab7, and did not co-localize with endosomal markers Rab4A, EEA1, and TPC1. MHCII lysosomal localization was corroborated by treatment with the lysosomolytic agent glycyl-l-phenylalanine-β-naphthylamide, which reduced the number of MHCII-positive vesicles. The surface presence of MHCII was revealed by immunolabeling of live non-permeabilized cells. In IFNγ-treated astrocytes, an increased fraction of large-diameter exocytotic vesicles (lysosome-like vesicles) with prolonged fusion pore dwell time and larger pore conductance was recorded, whereas the rate of endocytosis was decreased. Stimulation with ATP, which triggers cytosolic calcium signaling, increased the frequency of exocytotic events, whereas the frequency of full endocytosis was further reduced. In IFNγ-treated astrocytes, MHCII-linked antigen surface presentation is mediated by increased lysosomal exocytosis, whereas surface retention of antigens is prolonged by concomitant inhibition of endocytosis.

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LPS‐mediated release of ATP from urothelial cells occurs by lysosomal exocytosis

Silberfeld

Chavez

Obidike

et al. 2020

Neurourology and Urodynamics

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Background While numerous studies have confirmed ATP's importance in bladder physiology/pathophysiology, the literature is still conflicted regarding the mechanism of ATP release from the urothelium. Multiple mechanisms have been identified including non‐vesicular release via pannexin channels as well as vesicular release via a mechanism blocked by botulinum toxin. Recently, it has been shown that lysosomes contain significant stores of ATP which can be released extracellularly in response to Toll‐like receptor (TLR) stimulation. Objective The goal of the current study was to determine if lysosomal exocytosis occurs in urothelial cells in response to TLR4 stimulation by its agonist, bacterial lipopolysaccharide (LPS). Materials and Methods Human urothelial cells from an immortalized cell line (TRT‐HU1) were treated with bacterial LPS (100 μg/ml) or the nicotinic agoinist cytisine (100 μM) and extracellular release of ATP and lysosomal acid phosphatase were measured. Pannexin‐mediated ATP release and lysosomal ATP release were differentiated using Brilliant Blue FCF to inhibit pannexin channels and glycyl‐l‐phenylalanine‐β‐naphthylamide (GPN) to destroy lysosomes. The mechanisms controlling lysosomal exocytosis were examined using lysosomal pH measurements using LysoSensor dye and intracellular calcium signaling using Fura‐2. Results Stimulation of TRT‐HU1 cells with LPS significantly increased ATP release, which was inhibited by GPN, but not by Brilliant Blue FCF. Conversely, stimulation with cytisine induced ATP release that was sensitive to Brilliant Blue FCF but not GPN. LPS stimulation also induced the release of the lysosomal acid phosphatases. LPS increased lysosomal pH and direct alkalization of lysosomal pH using chloroquine or bafilomycin A1 induced ATP and acid phosphatase release, indicating an important role for pH in lysosomal exocytosis. Additionally, stimulation of lysosomal transient receptor potential mucolipin 1 calcium channels evoked intracellular calcium transients as well as ATP release. Conclusion These data indicate that LPS‐induced ATP release from urothelial cells is mediated by lysosomal exocytosis, a vesicular mechanism distinctly separate from non‐vesicular release via pannexin channels.

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Stimulation of TLR3 triggers release of lysosomal ATP in astrocytes and epithelial cells that requires TRPML1 channels

Cited by 36 publications

References 68 publications

Stimulus‐dependent modifications in astrocyte‐derived extracellular vesicle cargo regulate neuronal excitability

Stimulus‐dependent modifications in astrocyte‐derived extracellular vesicle cargo regulate neuronal excitability

Exocytosis of large-diameter lysosomes mediates interferon γ-induced relocation of MHC class II molecules toward the surface of astrocytes

LPS‐mediated release of ATP from urothelial cells occurs by lysosomal exocytosis

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