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Thesis defense – Florelle Domart

Tuesday 15 October 2019 / 09:30 - 11:30

Synchrotron X-ray fluorescence and super resolution correlative nanoimaging of metals and proteins in synapses of hippocampal neurons

Venue: Centre Broca Nouvelle-Aquitaine


Florelle Domart
IINS

Thesis supervised by Dr. Richard Ortega (CENBG) and Dr. Daniel Choquet (IINS)

Abstract

Abstract: Metallic chemical elements such as Fe, Cu or Zn are present in minute quantities in the brain. The role of these trace metals in neuronal functions such as synaptic transmission and memory processes remains largely unclear. Moreover, metal dyshomeostasis is found in many neuropathologies, such as Alzheimer’s disease, Parkinson’s or amyotrophic lateral sclerosis. The interaction mechanisms of trace metals at the neuronal level are difficult to describe because of the lack of analytical methods with appropriate resolution and sensitivity to determine metal distribution at the synaptic level. Synchrotron X-ray fluorescence spectrometry (SXRF) is a multielemental chemical analysis method for describing the quantitative distribution of these elements at the sub-cellular scale with a nanometric resolution (40 nm at ESRF beamline ID16A) and a very high sensitivity. In order to accurately interpret chemical imaging results, we have developed a protocol to correlate nano-SXRF imaging with stimulated emission depletion super resolution microscopy (STED), allowing the correlation of metal distribution and that of target proteins in super resolution. We labeled microtubules and F-actin of primary rat hippocampal neurons and imaged the cytoskeleton by STED microscopy before determining the distributions of P, S, Fe, Cu and Zn by SXRF spectrometry. We evidenced the colocalization of Zn and microtubules at the dendritic level and a localization of Cu mainly in the neck of dendritic spines rich in F-actin, and a distribution of Fe in the form of very localized points in the dendrites. These results highlight the crucial role of Zn in cytoskeleton architecture of hippocampal neurons and the developed correlative imaging method opens new perspectives for the study of metal dyshomeostasis in neurodegenerative diseases.

Keywords : analytical chemistry, neurobiology, trace metals, synchrotron, synapse, correlative microscopy

List of publications

Correlative synchrotron nano X-ray fluorescence and STED super resolution imaging of metals and proteins in dendritic spines ; Florelle Domart, Peter Cloetens, Stéphane Roudeau, Asuncion Carmona, Emeline Verdier, Daniel Choquet and Richard Ortega – submitted

Zinc and Copper Effects on Stability of Tubulin and Actin Networks in Dendrites and Spines of Hippocampal Neurons.Perrin L, Roudeau S, Carmona A, Domart F, Petersen JD, Bohic S, Yang Y6, Cloetens P, Ortega R ; ACS Chem Neurosci. 2017 Jul 19;8(7):1490-1499.

Jury

KUHN Alexander – Professeur, ENSCPB, Bordeaux
Examinateur

CARRIERE Marie – Chercheuse CEA, HDR, Grenoble
Rapporteuse

BUISSON Alain – Professeur, Université de Grenoble Alpes
Rapporteur

ISAURE Marie-Pierre – Maître de Conférences, HDR, IPREM Pau
Examinatrice

THOUMINE Olivier – DR CNRS, IINS, Bordeaux
Examinateur

ORTEGA Richard – DR CNRS, CENBG, Bordeaux-Gradignan
Directeur de thèse

CHOQUET Daniel – DR CNRS, IINS, Bordeaux
Co-directeur de thèse

CLOETENS Peter – Chercheur ESRF, Grenoble
Invité

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Details

Date:
Tuesday 15 October 2019
Time:
09:30 - 11:30
Event Category: