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Title: Development and application of novel molecular tools to study astrocyte-to-neurone communication in the brain
Author: Figueiredo, Melina Fernandes
ISNI:       0000 0004 5923 6595
Awarding Body: University of Bristol
Current Institution: University of Bristol
Date of Award: 2015
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My PhD project focused on the development and validation of new molecular tools expressing the variants of channelrhodopsin-2 (ChR2), ChR2(HI34R) and Ca2+ translocating channel rhodopsin (CatCh), and a potent ectonucleotidase, transmembrane prostatic acid phosphatase (TMPAP). Optogenetic stimulation of ChR2(H134R) and CatCh evoked astrocytic intracellular calcium ([Ca2+]i) elevations, which were mediated by Ca2+ release from the endoplasmic reticulum (ER), and autocrine action of ATP. [Ca2+]i transients in ChR2(H 134R)-expressing astrocytes were also partially dependent on external Ca2+, and led to astrocytic ATP release in response to photostimulation. The optogenetic actuator ChR2(HI34R) was employed in our published studies (Gourine et al., 201O; Marina et al., 2013; Tang et al., 2014) to selectively control astrocytic Ca2+ excitability, and gliotransmitter release in vitro and in vivo. The recent publication (Tang et al., 2014) led us to propose the existence of a novel receptor for L-lactate in central noradrenergic (NAergic) neurones. Therefore, the last segment of my PhD project involved the screening of orphan receptors for their sensitivity to L-lactate. This thesis also describes the ability of the novel v iral tool expressing TMP AP in interfering with purinergic signalling in vitro and in vivo by facilitating the · breakdown of released ATP. Degradation of ATP by TMPAP limited the propagation of Ca2+ waves in cultured astrocytes. TMPAP was employed in our pub I ished studies (Marina et al., 2013; Marina et al. , 2015; Wells et al., 2015) to investigate the role of A TP in several physiological paradigms. In conclusion, the developed optogenetic tools are able to successfully trigger physiologically relevant Ca2+ signals specifically in astrocytes, and TMPAP is a potent ectonucleotidase capable of degrading released ATP.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available