Neurotrophins (NGF, BDNF, NT-3) are endogenous growth factors that exert neuroprotective effects by preventing neuronal death and promoting neurogenesis. They act by binding to their respective high-affinity, pro-survival receptors TrkA, TrkB or TrkC, as well as to p75NTR death receptor. While these molecules have been shown to significantly slow or prevent neurodegeneration, their reduced bioavailability and inability to penetrate the blood-brain-barrier limit their use as potential therapeutics. To bypass these limitations, our research team has developed and patented small-sized, lipophilic compounds which selectively resemble neurotrophins’ effects, presenting preferable pharmacological properties and promoting neuroprotection and repair against neurodegeneration. In addition, the combination of these molecules with 3D cultured human neuronal cells, and their targeted delivery in the brain ventricles through soft robotic systems, could offer novel therapeutic approaches against neurodegenerative diseases and brain trauma.

The way single colloidal objects behave in presence of active forces arising from within the bulk of the system is crucial to many situations, notably biological and ecological (e.g. intra-cellular transport, predation), and potential medical or environmental applications (e.g. targeted delivery of cargoes, depollution of waters and soils). In this talk I will present experimental findings that my collaborators and I have obtained over the past years on the dynamics of single Brownian colloids in suspensions of biological micro-swimmers, especially the green alga Chlamydomonas reinhardtii. I'll show notably that spatial heterogeneities and anisotropies in the active particles statistics can control the preferential localisation of their passive counterparts. The results will be rationalized using theoretical approaches from hydrodynamics and stochastic processes.

A variety of pharmacological treatments exist for patients suffering from focal seizures, but systemically administered drugs offer only symptomatic relief and frequently cause unwanted side effects. Moreover, available drugs are ineffective in one third of the patients. Thus, developing more targeted and effective treatment strategies is highly warranted. Neurotrophic factors are candidates for treating epilepsy, but their development has been hampered by difficulties in achieving stable and targeted delivery of efficacious concentrations within the brain. We have developed an implantable cell encapsulation system that delivers high and consistent levels of neurotrophic molecules directly to a specific brain region. The potential of this approach has been tested by delivering glial cell line-derived neurotrophic factor (GDNF) to the hippocampus of epileptic rats. In vivo studies demonstrated that these intrahippocampal implants continue to secrete GDNF and produce high hippocampal GDNF tissue levels in a long-lasting manner. Identical implants rapidly and greatly reduced seizure frequency in the pilocarpine model. This effect increased in magnitude over 3 months, ultimately leading to a reduction of spontaneous seizures by more than 90%. Importantly, these effects were accompanied by improvements in cognition and anxiety, and by the normalization of many histological alterations that are associated with chronic epilepsy. In addition, the antiseizure effect persisted even after device removal. Finally, by establishing a unilateral epileptic focus using the intrahippocampal kainate model, we found that delivery of GDNF exclusively within the focus suppressed already established spontaneous recurrent seizures. Together, these results support the concept that the implantation of encapsulated GDNF-secreting cells can deliver GDNF in a sustained, targeted, and efficacious manner. These findings may form the basis for clinical translation of this approach.