DENDRITIC DEVELOPMENT IS IMPAIRED IN CLN8-DEFICIENT HIPPOCAMPAL NEURONAL MODEL.

PESAOLA F; QUASSOLLO G,; NOHER DE HALAC I.; BISBAL M

Carlos Paz

Congreso; AVH-Kolleg: Current Advances on Neurodegeneraon: From Molecular Biology to Translaonal Medicine; 2017

Alexander von Humboldt Stiftung/Fundation

nt roduc on:  CL N8- di s eas e bel ongs  t o t he group of  Neuronal  Ceroi d L i pof us c i nos es ,neurodegenerave disorders characterized by the abnormal lysosomal accumulaon of lipofuscinlikecompounds.ItiscausedbyadeficiencyofCLN8p,anEndoplasmicReculumresidentprotein.Itwasrelatedwiththesynthesis,transportanddeteconoflipids;however,itsroleremainsunknown.Weaim to study the effect of CLN8 expression levels on the morphology of neurons. Methods:Embryonic hippocampal rat neurons of 2 and 9 d.i.v. were transiently transfected with pYFP (control)alone or co-transfected with pCLN8wt (overexpression) or pshCLN8 (silencing). 2 d.i.v. neurons weremarked with an-Tau and an-Tubulin by immunostaining for axonal length measure. 9 d.i.v. neuronswere used for dendric branching study by Sholl analysis. Images were taken in an epifluorescencemicroscope and analyzed with ImageJ-Fiji soware. One-way ANOVA test was used to evaluate axonallength, and two-way ANOVA test with repeated measures was used for dendric evaluaon. Results:1) 2 d.i.v. neurons did not show meaningful differences regarding axonal length among treatments (p> 0.05). 2) 9 d.i.v. neurons did reveal significant variaons in dendric ramificaon measured.Dendric development in pshCLN8-treated cells was diminished compared with control cells (p <0.0001). Interesngly, neurons overexpressing CLN8 showed values between the other twocondions. Discussion: CLN8p deficiency affects dendric development, but not the axonal length.Our previous results showed a tendency of CLN8 to alter lysosomal distribuon in the cell body. Anappropriate lysosomal funcon and distribuon are required for a correct dendric development.Moreover, it was shown that changes in the morphology of dendrites are related with someneurodegenerave disorders. Now we propose that both overexpression and silencing of CLN8 affectthe development of dendrites possibly through altering lysosomal dynamics. These morphologicalchanges may be par t  of  t he pat hophysi ol ogy of  CLN8,  as was shown for  some ot herneurodegenerave diseases.