A patient-derived amyotrophic lateral sclerosis blood-brain barrier cell model reveals focused ultrasound-mediated anti-TDP-43 antibody delivery

Abstract

BackgroundAmyotrophic lateral sclerosis (ALS) is a rapidly progressing neurodegenerative disorder with minimally effective treatment options. An important hurdle in ALS drug development is the non-invasive therapeutic access to the motor cortex currently limited by the presence of the blood-brain barrier (BBB). Focused ultrasound and microbubble (FUS+MB) treatment is an emerging technology that was successfully used in ALS patients to temporarily open the cortical BBB. However, FUS+MB-mediated drug delivery across ALS patients’ BBB has not yet been reported. Similarly, the effects of FUS+MBon human ALS BBB cells remain unexplored.MethodsHere we established the first FUS+MB-compatible, fully-human ALS patient-cell-derived BBB model based on induced brain endothelial-like cells (iBECs) to study anti-TDP-43 antibody delivery and FUS+MBbioeffectsin vitro.ResultsGenerated ALS iBECs recapitulated disease-specific hallmarks of BBB pathology, including changes to BBB integrity, permeability and TDP-43 proteinopathy. Our results also identified differences between sporadic ALS and familial (C9orf72expansion carrying) ALS iBECs reflecting patient heterogeneity associated with disease subgroups. Studies in these models revealed successful ALS iBEC monolayer openingin vitrowith a lack of adverse cellular effects of FUS+MB. This was accompanied by the molecular bioeffects of FUS+MBin ALS iBECs including changes in expression of tight and adherens junction markers, and drug transporter and inflammatory mediators, with sporadic and C9orf72 ALS iBECs generating transient specific responses. Additionally, we demonstrated an effective increase in the delivery of anti-TDP-43 antibody with FUS+MBin C9orf72 (2.7-fold) and sporadic (1.9-fold) ALS iBECs providing the first proof-of-concept evidence that FUS+MBcan be used to enhance the permeability of large molecule therapeutics across the BBB in a human ALSin vitromodel.ConclusionsTogether, our study describes the first characterisation of cellular and molecular responses of ALS iBECs to FUS+MBand provides a fully-human platform for FUS+MB-mediated drug delivery screening on an ALS BBBin vitromodel.