NON-ANTIBIOTIC DOXYCYCLINE DERIVATIVE AGAINST A-SYNUCLEIN AGGREGATION

TOMAS-GRAU, RODRIGO; MARÍA DEL MILAGRO TERÁN; BESNAULT, PIERRE; TOURVILLE, A.; MELLA, R.; VILLACÉ, P.; SALADO, C.; ROSE, C.; SEON-MÉNIEL, B.; BRUNEL, J.; FERRIÉ, L.; MICHEL, P.; RAISMAN-VOSARI, R.; FIGADÈRE, B.; PLOPER, DIEGO; CHEHÍN, ROSANA

Granada

Congreso; 11th IBRO World Congress of Neuroscience; 2023

IBRO International Brain Research Organization (IBRO) and Spanish Neuroscience Society (SENC)

Parkinson´s disease is a neurodegenerative disorder with no cure to date, in which the misfolding andaggregation of α-synuclein (α-Syn) drives initiation and spreading of the pathology. Compelling evidenceindicate that doxycycline (DOX), a second-generation tetracycline (TC) with in vitro and in vivo anti-inflammatory and antioxidant effects, can interfere with the formation of toxic α-Syn species. However, theantibiotic activity of DOX represents an obstacle for its repurposing towards long-term treatments as thoserequired for neuroprotection. Therefore, we synthesized a reduced DOX derivative (DDox) by removal of thedimethylamino substituent at position 4 on ring A, and reduction of hydroxyl group at C12a. Thesemodifications fully reduced the antibiotic activity of DDox against Gram (+) and Gram (-) bacterial strains. Thenovel TC also preserved a lower toxicity on the SHSY5Y dopaminergic cell line, as tested by MTT assay. Inaddition, DDox proficiently interfered with the formation of α-Syn toxic aggregates, evidenced by fluorescentspectroscopy and transmission electron microscopy, where DDox showed higher effectiveness than itsprecursor DOX at inhibiting α-Syn amyloid aggregation. Results obtained using biophysical approaches werecomplemented by immunofluorescence in transgenic SHSY5Y cells that stably overexpresses α-Syn-tRFP,where aggregates were induced by incubation with exogenous α-Syn pre-formed fibrils (PFF). Addition ofthese PFF induced α-Syn-tRFP puncta, which stained positive for Thioflavin S and commercial α-Syn-aggregate-specific monoclonal antibodies. In this cellular model, co-incubation of PFF with DDox reducedthese markers. The characteristic anti-inflammatory properties of TC were conserved in DDox, since it efficientlyrescued LPS-induced TNF-α and Il-1β release in primary microglia cells. In summary, our results suggest thatthe novel DDox tetracycline is a non-toxic molecule with weak antibiotic activity and anti-inflammatory andneuroprotective properties, which make it an attractive molecule for in vivo preclinical studies of Parkinsondisease and other synucleinopathies.