Research Interest

The preservation of homeostasis in the brain is tightly controlled by transport mechanisms of ions, organic and inorganic molecules and parallel movement of water across the plasma-membrane and intracellular organelles. Hence, dysregulation of ion homeostasis due to altered function or mutations in ion channels or transporter proteins might influence pivotal cellular roles like neuronal excitability, signal transduction, pH and cell volume or vesicular trafficking among others, being critically involved in numerous neurological and neurodegenerative diseases. Particularly, proper brain function depends on astroglial-mediated homeostasis which is temporally and spatially dynamic and relies on such adaptations of the transport physiology at specific cellular microdomains. It is well acknowledged that perturbation of the surface expression of transporter proteins in astroglial cells also underlies various pathological conditions.

The aim of this program is to better understand the molecular and signaling mechanisms that govern the fluxes of inorganic ions and organic osmolytes across cellular and intracellular membranes and whose malfunction impinges on neuronal function leading to neuronal demise in many neurological conditions, with an especial focus in the bidirectional communication between neurons and glial cells. The program uses a range of multidisciplinary approaches and embraces many facets of ion channel and membrane transport research ranging from protein structure, genetics, biochemistry, cell biology and physiology, to animal behavior and human disease.

• Understanding the physiological roles of the plasma-membrane chloride channels of the CLC and LRRC8 family which are illustrated in human hereditary diseases caused by mutations in their genes or auxiliary subunits (GlialCAM, MLC1,…) which regulate their functions, and to provide therapeutic solutions to patients affected by their malfunctioning.

• Gaining insights in the structure and physiopathology of the choline-like transporters (SLC44 family) due to their recent association to neurodevelopmental disorders, sensorineural and autoimmune syndromes and cancer, turning them into a potential therapeutic target.

• Deciphering the molecular and regulatory mechanisms underlying organellar ion homeostasis of endolysosomes and their impact on synaptic function, whose dysregulation leads directly or indirectly to synapse dysfunction and thereby to neurological disorders (lysosomal storage disorders, neurodegenerative diseases…).

Technologies & Methods

• Cell culture methods
• Primary cultures (neurons and astrocytes)
• Reprogramming and Stem Cell Technologies
• CRISPR gene editing
• General techniques of molecular biology and biochemistry (qPCR, cloning, western blot, purification of synaptosomes,…)
• Protein-protein interactions: FRET, BRET, BiFC, SplitTEV, Nanobit, coIP, Retention assays, yeast two-hybrid
• Membrane protein solubilization and purification, isolation of synaptic nerve terminals or synaptosomes
• Electrophysiology: two electrode voltage clamp, whole-cell patch clamp.
• Live Imaging: genetically encoded fluorescent biosensors, calcium imaging, pH measurements. sensor-/tracer-based functional assays
• TIRF, Confocal, spinning-disk, super-resolution microscopy
• Histology
• Mass-spectrometry
• Protein structure, x-ray
• Mice models of disease

Active Projects

Conocimientos estructurales y moleculares de las proteínas de MLC que regulan canales de cloruro astrocitarios: Búsqueda de terapias para MLC y epilèpsia. Ministerio de Ciencia, Innovación y Universidades. PID2021-126246NB-I00. Raul Estevez

1 Confidential agreement

Selected Publications

• • Formaggio, F., Fazzina, M., Estévez, R., Caprini, M., & Ferroni, S. (2022). Dynamic expression of homeostatic ion channels in differentiated cortical astrocytes in vitro. Pflügers Archiv – European Journal of Physiology, 474(2), 243–260. https://doi.org/10.1007/s00424-021-02627-x

• • Pla-Casillanis, A., Ferigle, L., Alonso-Gardón, M., Xicoy-Espaulella, E., Errasti-Murugarren, E., Marazziti, D., & Estévez, R. (2022). GPR37 Receptors and Megalencephalic Leukoencephalopathy with Subcortical Cysts. International Journal of Molecular Sciences, 23(10), 5528. https://doi.org/10.3390/ijms23105528

• • Wang, B. B., Xu, H., Isenmann, S., Huang, C., Elorza-Vidal, X., Rychkov, G. Y., Estévez, R., Schittenhelm, R. B., Lukacs, G. L., & Apaja, P. M. (2022). Ubr1-induced selective endophagy/autophagy protects against the endosomal and Ca2+-induced proteostasis disease stress. Cellular and Molecular Life Sciences, 79(3), 167. https://doi.org/10.1007/s00018-022-04191-8