Exocytosis, endocytosis and recycling of secretory vesicles in neuroendocrine cells, and its regulation by cortical actin

C罵DENAS, ANA M.; Gallo, Luciana I.; Marengo, Fernando D.

doi:10.32604/biocell.2022.019086

Cited by 5 publications

(3 citation statements)

References 69 publications

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“…It is well known that endocytosis and exocytosis are influenced by actin dynamics (Grassart et al, 2014; Gabel et al, 2015; Cárdenas et al, 2022; Montenegro et al, 2021), and that A618T and S619L mutations disrupt the formation of actin filaments (F-actin) in skeletal myoblasts (Bayonés et al, 2022a). In consequence, we decided to analyze the effect of these mutations on actin dynamics in bovine chromaffin cells.…”

Section: Resultsmentioning

confidence: 99%

Dynamin-2 Mutations Linked to Neonatal-onset Centronuclear Myopathy impair exocytosis and endocytosis in adrenal chromaffin cells

Bayonés,

Guerra-Fernández,

Figueroa-Cares

et al. 2024

Preprint

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Dynamins are large GTPases whose primary function is to catalyze membrane scission during endocytosis, but also modulate other cellular processes, such as actin polymerization and vesicle trafficking. Recently, we reported that centronuclear myopathy associated dynamin-2 mutations, p.A618T and p.S619L, impair Ca2+-induced exocytosis of GLUT4 containing vesicles in immortalized human myoblasts. As exocytosis and endocytosis occur within rapid timescales, here we applied high-temporal resolution techniques, such as patch-clamp capacitance measurements and carbon-fiber amperometry to assess the effects of these mutations on these two cellular processes using bovine chromaffin cells as a study model. We found that the expression of any of these dynamin-2 mutants inhibits a dynamin and F-actin dependent form of fast endocytosis triggered by single action potential stimulus, as well as inhibits a slow compensatory endocytosis induced by 500 ms square depolarization. Both dynamin-2 mutants further reduced the exocytosis induced by 500 ms depolarizations, and the frequency of release events and the recruitment of NPY-labelled vesicles to the cell cortex after stimulation of nicotinic acetylcholine receptors with DMPP. They also provoked a significant decrease in the Ca2+-induced formation of new actin filaments in permeabilized chromaffin cells. In summary, our results indicate that the CNM- linked p.A618T and p.S619L mutations in dynamin-2 affect exocytosis and endocytosis, being the disruption of F-actin a possible explanation for these results. These impaired cellular processes might underlie the pathogenic mechanisms associated with these mutations.

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Section: Resultsmentioning

confidence: 99%

Dynamin-2 Mutations Linked to Neonatal-onset Centronuclear Myopathy impair exocytosis and endocytosis in adrenal chromaffin cells

Bayonés,

Guerra-Fernández,

Figueroa-Cares

et al. 2024

Preprint

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“…Importantly, actin dynamics control different stages of the secretory process in chromaffin cells, including vesicle mobility, docking, and fusion at exocytotic sites (Cárdenas et al, 2022). Thus, these two mechanisms, increased PI(4,5)P 2 stability and actin dynamics, might further contribute to the action of P2X7 receptors on exocytosis.…”

Section: Discussionmentioning

confidence: 99%

“…The P2X7 receptors also interact with elements of the actomyosin cytoskeleton, including β‐actin, α‐actinin, and the myosin regulatory light chain and the unconventional myosin‐Va (see Kopp et al, 2019) and regulates, in macrophages, the actin cytoskeleton in a Ca 2+ ‐independent way (Pfeiffer et al, 2004). Importantly, actin dynamics control different stages of the secretory process in chromaffin cells, including vesicle mobility, docking, and fusion at exocytotic sites (Cárdenas et al, 2022). Thus, these two mechanisms, increased PI(4,5)P 2 stability and actin dynamics, might further contribute to the action of P2X7 receptors on exocytosis.…”

Section: Discussionmentioning

confidence: 99%

Autocrine activation of P2X7 receptors mediates catecholamine secretion in chromaffin cells

Maldifassi,

Guerra‐Fernández,

Ponce

et al. 2024

British J Pharmacology

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Background and PurposeATP is highly accumulated in secretory vesicles and secreted upon exocytosis from neurons and endocrine cells. In adrenal chromaffin granules, intraluminal ATP reaches concentrations over 100 mM. However, how these large amounts of ATP contribute to exocytosis has not been investigated.Experimental ApproachExocytotic events in bovine and mouse adrenal chromaffin cells were measured with single cell amperometry. Cytosolic Ca2+ measurements were carried out in Fluo‐4 loaded cells. Submembrane Ca2+ was examined in PC12 cells transfected with a membrane‐tethered Ca2+ indicator Lck‐GCaMP3. ATP release was measured using the luciferin/luciferase assay. Knockdown of P2X7 receptors was induced with short interfering RNA (siRNA). Direct Ca2+ influx through this receptor was measured using a P2X7 receptor‐GCamp6 construct.Key ResultsATP induced exocytosis in chromaffin cells, whereas the ectonucleotidase apyrase reduced the release events induced by the nicotinic agonist dimethylphenylpiperazinium (DMPP), high KCl, or ionomycin. The purinergic agonist BzATP also promoted a secretory response that was dependent on extracellular Ca2+. A740003, a P2X7 receptor antagonist, abolished secretory responses of these secretagogues. Exocytosis was also diminished in chromaffin cells when P2X7 receptors were silenced using siRNAs and in cells of P2X7 receptor knockout mice. In PC12 cells, DMPP induced ATP release, triggering Ca2+ influx through P2X7 receptors. Furthermore, BzATP, DMPP, and KCl allowed the formation of submembrane Ca2+ microdomains inhibited by A740003.Conclusion and ImplicationsAutocrine activation of P2X7 receptors constitutes a crucial feedback system that amplifies the secretion of catecholamines in chromaffin cells by favouring submembrane Ca2+ microdomains.

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Gain-of-function dynamin-2 mutations linked to centronuclear myopathy impair Ca²⁺-induced exocytosis in human myoblasts

Bayonés

Fernandez

Hinostroza

et al. 2022

Preprint

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Gain-of-function mutations of dynamin-2, a mechano-GTPase that remodels membrane 25 and actin filaments, cause centronuclear myopathy (CNM), a congenital disease that mainly affects skeletal muscle tissue. Among these mutations, the variants p.A618T and p.S619L lead to gain of function and cause a severe neonatal phenotype. By using total internal reflection fluorescence microscopy (TIRFM) in immortalized human myoblasts expressing the pH-sensitive fluorescent protein (pHluorin) fused to the insulin-responsive aminopeptidase IRAP as reporter of the GLUT4 vesicle-trafficking, we measured single pHluorin signals to investigate how p.A618T and p.S619L mutations influence exocytosis. We show here that both dynamin-2 mutations significantly reduced the number and durations of pHluorin signals induced by 10 uM ionomycin, indicating that in addition to impair exocytosis, they also affect the fusion pore dynamics. These mutations also disrupt the formation of actin filaments, a process that reportedly favors exocytosis. This altered exocytosis might importantly disturb the plasmalemma expression of functional proteins such as the glucose transporter GLUT4 in skeletal muscle cells, impacting the physiology of the skeletal muscle tissue and contributing to the CNM disease.

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Exocytosis, endocytosis and recycling of secretory vesicles in neuroendocrine cells, and its regulation by cortical actin

Cited by 5 publications

References 69 publications

Dynamin-2 Mutations Linked to Neonatal-onset Centronuclear Myopathy impair exocytosis and endocytosis in adrenal chromaffin cells

Dynamin-2 Mutations Linked to Neonatal-onset Centronuclear Myopathy impair exocytosis and endocytosis in adrenal chromaffin cells

Autocrine activation of P2X7 receptors mediates catecholamine secretion in chromaffin cells

Gain-of-function dynamin-2 mutations linked to centronuclear myopathy impair Ca²⁺-induced exocytosis in human myoblasts

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Exocytosis, endocytosis and recycling of secretory vesicles in neuroendocrine cells, and its regulation by cortical actin

Cited by 5 publications

References 69 publications

Dynamin-2 Mutations Linked to Neonatal-onset Centronuclear Myopathy impair exocytosis and endocytosis in adrenal chromaffin cells

Dynamin-2 Mutations Linked to Neonatal-onset Centronuclear Myopathy impair exocytosis and endocytosis in adrenal chromaffin cells

Autocrine activation of P2X7 receptors mediates catecholamine secretion in chromaffin cells

Gain-of-function dynamin-2 mutations linked to centronuclear myopathy impair Ca2+-induced exocytosis in human myoblasts

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Gain-of-function dynamin-2 mutations linked to centronuclear myopathy impair Ca²⁺-induced exocytosis in human myoblasts