Tedeschi, Valentina
(2018)
Role of the lysosomal channel Transient Receptor Potential Mucolipin 1 (TRPML1) in the functional coupling between endoplasmic reticulum and lysosomes in experimental models of brain ischemia.
[Tesi di dottorato]
| Tipologia del documento: |
Tesi di dottorato
|
| Lingua: |
English |
| Titolo: |
Role of the lysosomal channel Transient Receptor Potential Mucolipin 1 (TRPML1) in the functional coupling between endoplasmic reticulum and lysosomes in experimental models of brain ischemia |
| Autori: |
| Autore | Email |
|---|
| Tedeschi, Valentina | valentina.tedeschi@unina.it |
|
| Data: |
11 Dicembre 2018 |
| Numero di pagine: |
113 |
| Istituzione: |
Università degli Studi di Napoli Federico II |
| Dipartimento: |
Neuroscienze e Scienze Riproduttive ed Odontostomatologiche |
| Dottorato: |
Neuroscienze |
| Ciclo di dottorato: |
31 |
| Coordinatore del Corso di dottorato: |
| nome | email |
|---|
| Taglialatela, Maurizio | mtaglial@unina.it |
|
| Tutor: |
| nome | email |
|---|
| Secondo, Agnese | [non definito] |
|
| Data: |
11 Dicembre 2018 |
| Numero di pagine: |
113 |
| Parole chiave: |
Brain ischemia; intracellular calcium homeostasis; lysosomes/endoplasmic reticulum coupling; autophagy |
| Settori scientifico-disciplinari del MIUR: |
Area 05 - Scienze biologiche > BIO/14 - Farmacologia |
[error in script]
[error in script]
| Depositato il: |
19 Dic 2018 11:34 |
| Ultima modifica: |
23 Giu 2020 09:27 |
| URI: |
http://www.fedoa.unina.it/id/eprint/12682 |
Abstract
A growing interest has been recently devoted to the role of intracellular Ca2+ stores in brain ischemia. For instance, disturbances of Ca2+ content in the endoplasmic reticulum (ER), the main intracellular Ca2+ store, have been reported as one of the main mechanisms underlying this neurological disease. Interestingly, lysosomes are emerging as other important Ca2+-storing organelles, cooperating with the ER in the handling of intracellular Ca2+ concentration ([Ca2+]i). One of the main regulators of lysosomal Ca2+ homeostasis is represented by Transient Receptor Potential Mucolipin 1 (TRPML1), a non-selective cation channel releasing lysosomal Ca2+ into the cytosol.
In this study we investigated the role of ER/lysosome Ca2+ coupling and the contribution of TRPML1 in brain ischemia. Our results showed that under physiological conditions TRPML1 activation induced by its specific agonist ML-SA1 or by lysosomal v-ATPase inhibitor bafilomycin A1 significantly increased [Ca2+]i in cortical neurons. ML-SA1-induced Ca2+ leak from lysosomes strongly reduced ER Ca2+ content, whereas the TRPML1 inhibitor trans-Ned19 or channel knocking down increased ER Ca2+ levels. However, this interplay was disrupted under hypoxic conditions produced by exposing cortical neurons to oxygen and glucose deprivation (OGD) followed by reoxygenation (Rx). Indeed, during OGD/Rx both ER and lysosomal Ca2+ levels were significantly impaired. Interestingly, the administration of trans-Ned19 during the reoxygenation phase prevented dysfunctional lysosomal Ca2+ homeostasis and neuronal death. In consideration of the role played by lysosomes in autophagy regulation, we showed that trans-Ned19 hampered the autophagic flux during hypoxia thus protecting neurons. Moreover, we found that in ischemic rats subjected to the transient occlusion of the middle cerebral artery (tMCAO) the intracerebroventricular (icv) administration of this drug at the onset of reperfusion was able to reduce the brain ischemic volume, ameliorated the general and focal deficits, and promoted a protective blockade of the autophagic flux.
Collectively, the results presented in my PhD thesis demonstrate the detrimental role of TRPML1 dysfunction in the neurodegeneration associated to brain ischemia, thus identifying a novel potential therapeutic target that could be pharmacologically modulated, together with other relevant mechanisms, to induce neuroprotection.
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