Résumé du projet (environ une demi-page)

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline and memory loss. The accumulation of extracellular β-amyloid plaques and neurofibrillary tangles are major pathological hallmarks of AD. Nonetheless, other cellular dysfunctions, often occurring years before the plaques appearance, manifest at early, preclinical stages. Such dysfunctions include alterations of mitochondrial bioenergetics, calcium/lipid transport between the endoplasmic reticulum (ER) and the mitochondria, disruption in cholesterol metabolism, and increase in lipid droplets (LD). However, the mechanisms that trigger these apparently unrelated features in AD are unknown. Emerging research underscores the significance of interactions between ER and mitochondria in AD pathogenesis. Mitochondria and the ER are crucial for cellular homeostasis, including calcium signaling, lipid metabolism, and energy production. Lipid droplets, once considered mere lipid storage sites, are now recognized as dynamic organelles involved in lipid metabolism and signaling. We recently found that ER subdomains, also known as Mitochondria Associated ER Membranes (MAM), are hotspots for LD biogenesis, revealing the existence of a novel mitochondria-ER-LD junction. In Alzheimer’s disease, dysregulation of lipid metabolism and mitochondrial function is evident.  We hypothesize that the interaction between mitochondria, ER, and LD, facilitated by these contact sites, is essential for lipid transfer and metabolic regulation. We also hypothesize that the early cellular dysfunctions in AD, especially those involving mitochondria and LD, could be all orchestrated at MAM.

This project aims to elucidate the role of mitochondria-ER-LD contact sites in the development and progression of Alzheimer’s disease, focusing on sporadic AD models and the impact of ApoE variants, particularly ApoE4, a major genetic risk factor for AD. The master M2 student will employ multiple imaging techniques and biochemical assays  to 1) visualize and quantify the localization of key lipid transfer proteins at MAM-LD contact sites, as well as the morphology of these contacts, using confocal and electron microscopy; 2) analyse and quantify the endogenous interactions of these lipid transfer proteins at MAM-LD contact sites by Proximity Ligation Assays (PLA). These experiments will be performed in sporadic AD cellular models (neuronal and astrocyte cell lines) expressing different ApoE variants (ApoE3 and ApoE4). If time allows the distribution of specific lipids (fluorescently tagged) across mitochondria-ER-LD will be analysed by using confocal imaging in these cells.

This project will provide novel insights into the cellular mechanisms underlying Alzheimer’s disease, with a focus on the role of ApoE variants in modulating mitochondria-ER-LD interactions and composition. Understanding these mechanisms could identify new therapeutic targets focused on organelle interactions and lipid metabolism, offering innovative strategies to combat this debilitating disease.


Dernières Publications en lien avec le projet :


Monteiro-Cardoso VF* and Giordano F* (2024). Emerging functions of the mitochondria–ER–lipid droplet three-way junction in coordinating lipid transfer, metabolism, and storage in cells. FEBS Letters, Vol 598, 10:1252-1273.   doi: 10.1002/1873-3468.14893

Monteiro-Cardoso VF, Le Bars R, Giordano F*. (2023). Visualization and quantification of endogenous intra-organelle protein interactions at ER-mitochondria contacts sites by Proximity Ligation Assays. J Vis Exp Oct 20:(200). doi: 10.3791/64750

Monteiro-Cardoso VF, Rochin L, Arora A, Houcine A, Jääskeläinen E, Kivelä AM., Sauvanet C, Le Bars R, Marien E, Dehairs J, Neveu J, El Khallouki N, Santonico E, Swinnen JV, Tareste D,  Olkkonen MV, Giordano F*. (2022). ORP5/8 and MIB/MICOS Link ER-mitochondria and intermitochondrial contacts for non-vesicular transport of phosphatidylserine. Cell Reports, Sep 20;40(12):111364. doi: 10.1016/j.celrep.2022.111364

Guyard V, Monteiro-Cardoso VF, Omrane M, Sauvanet C, Houcine A, Boulogne C, Ben Mbarek K, Vitale N, Facklaris O, El Khallouki N, Thiam AR*, Giordano F*. (2022).ORP5 and ORP8 orchestrate lipid droplet biogenesis and maintainance at ER-mitochondria contact sites. Journal of Cell Biology, Sep 5;221(9):e202112107. doi: 10.1083/jcb.202112107

 Ce projet s’inscrit-il dans la perspective d’une thèse :

                                                       oui   X                                                           non o

 si oui type de financement prévu :  Paris Saclay or ANR

 Ecole Doctorale de rattachement :  SDSV