Direct CNS delivery of proteins using thermosensitive liposome-in-gel carrier by heterotopic mucosal engrafting

Abstract

Delivering therapeutics across the blood-brain barrier (BBB) for treating central nervous system (CNS) diseases is one of the biggest challenges today as the BBB limits the uptake of molecules greater than 500 Da into the CNS. Here we describe a novel trans-nasal mucosal drug delivery as an alternative to the intranasal drug delivery to overcome its limitations and deliver high molecular weight (HMW) therapeutics efficiently to the brain. This approach is based on human endoscopic skull base surgical techniques in which a surgical defect is repaired by engrafting semipermeable nasal mucosa over a skull base defect. Based on endoscopic skull based surgeries, our groups has developed a trans-nasal mucosal rodent model where we have evaluated the permeability of ovalbumin (45 kDa) as a model protein through the implanted mucosal graft for delivering HMW therapeutics to the brain. A thermo sensitive liposome-in-gel (LiG) system was developed for creating a drug depot allowing for a sustained release from the site of delivery to the brain through the implanted nasal graft. We would like to report this as an exploratory pilot study where we are using this novel surgical model to show that the implanted nasal mucosal graft and the LiG delivery system result in an efficient and a sustained brain delivery of HMW proteins. Hence, this study demonstrates that the trans-nasal mucosal engrafting technique could overcome the limitations for intranasal drug delivery and enable the uptake of HMW protein therapeutics into the CNS for the treatment of a wide range of neurodegenerative diseases.

Intranasal Delivery and Transfection of mRNA Therapeutics in the Brain Using Cationic Liposomes

“…1 Briefly, the lipids comprising 1,2-dipalmitoyl-snglycero-3-phosphocholine (DPPC) (Avanti Polar Lipids, Alabaster, AL), 1,2-dioleoyl-3-trimethylammonium-propane chloride salt (DOTAP) (Avanti Polar Lipids, Alabaster, AL), and cholesterol (stabilizer) (Sigma-Aldrich, St. Louis, MO) were weighed and dissolved in chloroform at a 5:5:3 molar ratio (DPPC/DOTAP/cholesterol), respectively. 30 The organic solvent was evaporated using rotary evaporation under a vacuum (100 rpm, 180 mBAR, IKA RV 10 rotary evaporator, Wilmington, NC-28405, Model RV 10 C S99) forming a uniform film in a round-bottom flask at room temperature. The film was further kept under a vacuum for 12 h for the removal of residual chloroform.…”

“…25,26 We have previously shown that the cationic liposomes are nontoxic in vitro 27 and can be successfully employed for brain delivery and protein therapeutics via either liposomes (GDNF) 28,29 or liposomes in the gel system (BDNF AntagoNAT Oligonucleotides). 27,30 Given the encouraging background, we hypothesized that the combination of cationic liposomes for mRNA encapsulation and intranasal route should mediate higher mRNA transfection in the brain with less off-target effects. However, optimization of the factors such as the mRNA dose and time of transfection plays a vital role in the design of therapeutic mRNA studies for neurodegenerative disorders.…”

Endonasal CNS Delivery System for Blood-Brain Barrier Impermeant Therapeutic Oligonucleotides Using Heterotopic Mucosal Engrafting

“…Our group has previously reported on a novel method of permanently bypassing the BBB using an endoscopic heterotopic mucosal grafting technique within the nasal cavity (Pawar et al, 2018). This technique is based on established endoscopic skull base surgical techniques to repair the skull base following intradural approaches using mucosal grafts including the nasoseptal flap (Ishii et al, 2014;Miyake and Bleier, 2015a).…”

“…In the current study we utilized an established rodent mucosal graft model previously developed by our group (Pawar et al, 2018) to determine the distribution and efficacy of transmucosal BDNF AT delivery in naïve rats and in a 6-OHDA model of PD. In order to further enhance the drug delivery and to protect the BDNF AT's from nucleases, we also utilized a 200-250 nm cationic liposomal system.…”

Editorial: Neuroprotection and Disease Modification in Parkinson’s Disease

“…The delivered BDNF AT’s encapsulated in liposomes conferred neuroprotection in a rat 6-OHDA model of PD. ( Pawar et al, 2018 ; Bleier et al, 2015 ).…”