Biology subjects

Bar-On, D.

Publications and source records attributed to Bar-On, D..

2 recordsLinked to original sources

bioRxiv2025

Low-frequency ultrasound-mediated blood-brain barrier opening enables non-invasive lipid nanoparticle RNA delivery to glioblastoma

Ionizable Lipid Nanoparticles (LNPs) are an FDA-approved non-viral RNA delivery system, though their use for brain therapy is restricted by the blood-brain barrier (BBB). Focused ultrasound combined with microbubbles can disrupt the BBB, but delivering large particles requires balancing increased peak negative pressures while maintaining microvascular integrity. Herein, we optimized low-frequency ultrasound parameters to induce high-amplitude microbubble oscillations, enabling the safe delivery of LNPs across the BBB. First, BBB opening was assessed at different frequencies (850, 250, and 80 kHz) and pressures by monitoring the extravasation of Evans blue (~1 kDa). Next, the delivery of 4, 70, and 150 kDa Dextrans, LNPs entrapping Cy5-siRNAs (~70 nm in diameter), and LNPs entrapping mRNA (~100 nm in diameter) was evaluated via microscopy and bioluminescence. In a glioblastoma syngeneic mouse model, siRNA-Cy5-LNP was successfully delivered. A frequency of 850 kHz and 125 kPa pressure induced safe BBB opening, enabling delivery of both small molecules and LNPs. In healthy brains, LNP entrapping siRNAs delivery increased 10-fold compared to controls, and LNPs with mRNAs showed a 12-fold increase in bioluminescence after 24 hours. In glioblastoma tumors, LNPs with siRNAs delivery resulted in a 6.7-fold increase in fluorescence. This study paves the way for non-invasive LNP delivery to the brain, offering a versatile platform for brain therapies. TOC graphic O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=76 SRC="FIGDIR/small/634427v1_ufig1.gif" ALT="Figure 1"> View larger version (32K): org.highwire.dtl.DTLVardef@cad2bdorg.highwire.dtl.DTLVardef@1d1936corg.highwire.dtl.DTLVardef@259d83org.highwire.dtl.DTLVardef@1883aed_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2018

Depopulation of α-synuclein aggregates is associated with rescue of dopamine neuron dysfunction and death in a new Parkinson disease model

Parkinsons Disease (PD) is characterized by the presence of -synuclein aggregates known as Lewy bodies and Lewy neurites, whose formation is linked to disease development. The causal relation between -synuclein aggregates and PD is not well understood. We generated a new transgenic mouse line (MI2) expressing human, aggregation-prone truncated 1-120 -synuclein under the control of the tyrosine hydroxylase promoter. MI2 mice exhibit progressive aggregation of -synuclein in dopaminergic neurons of the substantia nigra pars compacta and their striatal terminals. This is associated with a progressive reduction of striatal dopamine release, reduced striatal innervation and significant nigral dopaminergic nerve cell death starting from 6 and 12 months of age, respectively. Overt impairment in motor behavior was found in MI2 mice at 20 months of age, when 50% of dopaminergic neurons are lost. These changes were associated with an increase in the number and density of 20-500nm -synuclein species as shown by dSTORM. Treatment with the oligomer modulator anle138b, from 9-12 months of age, restored striatal dopamine release and prevented dopaminergic cell death. These effects were associated with a reduction of the inner density of -synuclein aggregates and an increase in dispersed small -synuclein species as revealed by dSTORM. The MI2 mouse model recapitulates the progressive dopaminergic deficit observed in PD, showing that early synaptic dysfunction precedes dopaminergic axonal loss and neuronal death that become associated with a motor deficit upon reaching a certain threshold. Our data also provide new mechanistic insight for the effect of anle138bs function in vivo supporting that targeting -synuclein aggregation is a promising therapeutic approach for PD.

neuroscience↗