Research

We use cutting-edge optical tools to study synaptic biology, focusing on understanding the molecular mechanisms controlling synaptic transmission.

Our lab aims to understand the molecular underpinnings controlling synaptic function to ultimately dissect how its dysregulation affects brain physiology and impacts human disease. We use cutting-edge optical tools to examine diverse aspects of the biology of synapses to develop a detailed picture of the molecular mechanisms controlling synaptic transmission. Our overarching goal is to provide actionable knowledge that can be used to design better strategies for screening, prevention, and treatment of human diseases. We collaborate with physicians at the Pitié-Salpêtrière Hospital to study human brain physiology and to increase our understanding on the synaptic molecular drivers of epilepsy and other neurological diseases.

The brain is acutely sensitive to metabolic compromise and recent research demonstrates that nerve terminals represent one of the key loci of this vulnerability (Rangaraju et al. Cell 2014). Mitochondria generate more than 90% of the neuronal bioenergy in the form of ATP but how synapses guarantee the necessary ATP levels required for neurotransmission is poorly understood. Mitochondrial dysfunction is at the center of many neurological diseases and a notable example of this is epilepsy, in which pathogenic mutations in 169 genes that affect mitochondrial function have been found to cause seizures (Zsurka and Kunz. Lancet Neurology 2015). Our lab aims to understand at the molecular level the missing link between mitochondrial dysfunction, synaptic bioenergetics and neurotransmission to unravel key mechanisms of neurological disease associated with dysfunctional bioenergetics. We recently shown that upscaling mitochondrial metabolism in memory circuits of flies and mice boost long-term memory formation. This shows that energy in the brain does not only have a supporting role for neuronal function, but can act as a governing factor driving behavior. See our work here!

While electrophysiology has been essential to dissect the function and excitability of neurons for decades, the recent development of powerful optical tools has revolutionized the limits of what can be studied in neuronal biology. In the lab we work to push the limits of current optical techniques to be able to explore biology that was previously inaccessible. We collaborate with other labs to develop novel indicators (see de Juan-Sanz et al. Neuron 2017). Using light for reading out neuronal function creates two main advantages for understanding neuronal biology: 1) it is noninvasive and can be easily targeted to specific neuronal populations and 2) it allows studying many functional aspects of single neurons with subcellular resolution. In addition, light is multiplexable, allowing multiple tasks to be performed by discrete wavelengths, which facilitates the study of several aspects of neuronal function at once.

ER-GCaMP6-150 is a novel indicator for ER Ca2+! Get it here: https://www.addgene.org/86918/

Pre- and post-synaptic sites are held together by trans-synaptic molecules, which provide structural support to enhance synaptic efficacy. However, certain trans-synaptic molecules associate with pre- and post-synaptic proteins to actively modulate neurotransmission, controlling for example the efficacy of ion channels. One example for this is the secreted trans-synaptic molecule LGI1, whose function at the presynapse controls the activity of potassium channels, modulating the shape of the action potential waveform invading a presynaptic site. We recently developed novel optical tools to visualize in firing synapses the molecular behavior of LGI1 and its presynaptic receptor, ADAM23, and discovered that neuronal activity acutely rearranges the abundance of these proteins at the synaptic cleft, facilitating the formation of trans-synaptic connections proportionally to the history of activity of the synapse (Cuhadar & Calzado-Reyes et al 2022). Using omics approaches, we have developed a system to quantify the exocytome of active presynapses to test whether additional trans-synaptic proteins can be acutely rearranged on demand, thus showing that the trans-synaptic cleft is much more dynamic than initially thought.

Join Us!

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Update 2024: WE HAVE AN OPENING FOR LAB TECHNICIAN / INGENIEUR D’ETUDES: See the offer here.

In our Lab we strongly value scientific excellence and rigor. It is also essential, though, that everyone experiences a positive, engaging, hostility-free, challenging and rewarding lab environment. We support/collaborate with each other in the lab and we celebrate each other’s victories, no matter how small. Science is difficult and requires hard work and perseverance, so we believe that having fun is essential to enjoy our discoveries. We also believe in #openscience and we provide free access to all our work by uploading our manuscripts to biorxiv and by sharing our tools with the community.

We are always looking for talented people to join the team! Are you looking for a postdoctoral position? Get in touch at jaime.dejuansanz@icm-institute.org, attach your CV and give us a short explanation on your interest in joining the lab.

If you want to take a look to Jaime’s CV, you can check here: CV de Juan-Sanz

Lab members

Carlos Pascual-Caro

Postdoc

Anjali A. Vishwanath

Postdoc

Lorenzo Calzado Reyes

PhD Student

Agathe Moret

PhD Student

Mario Lopez Manzaneda

Postdoc

Sarah Thomas Broome

Postdoc

Kahina Boumendil

Lab manager

Angela Garcia Pelayo

Undergrad

Xintong Men

M1 student

Alumni:

  • Ulku Cuhadar, Postdoc
  • Anushree Kumar, Technician.
  • Esperance Nku-Mokabo, Technician

Location

Our lab is located in the ICM – Paris Brain Institute, in the center of Paris.

We are located in the center of Paris in a state-of-the-art building that hosts 28 research groups working on all aspects of neurosciences, from basic to clinical research.

The ICM is also an integral part of Sorbonne Université, France’s leading university in medical and scientific teaching and research.