A Carrier for Non-Covalent Delivery of Functional Beta-Galactosidase and Antibodies against Amyloid Plaques and IgM to the Brain

Abstract

BackgroundTherapeutic intervention of numerous brain-associated disorders currently remains unrealized due to serious limitations imposed by the blood-brain-barrier (BBB). The BBB generally allows transport of small molecules, typically <600 daltons with high octanol/water partition coefficients, but denies passage to most larger molecules. However, some receptors present on the BBB allow passage of cognate proteins to the brain. Utilizing such receptor-ligand systems, several investigators have developed methods for delivering proteins to the brain, a critical requirement of which involves covalent linking of the target protein to a carrier entity. Such covalent modifications involve extensive preparative and post-preparative chemistry that poses daunting limitations in the context of delivery to any organ. Here, we report creation of a 36-amino acid peptide transporter, which can transport a protein to the brain after routine intravenous injection of the transporter-protein mixture. No covalent linkage of the protein with the transporter is necessary.ApproachA peptide transporter comprising sixteen lysine residues and 20 amino acids corresponding to the LDLR-binding domain of apolipoprotein E (ApoE) was synthesized. Transport of beta-galactosidase, IgG, IgM, and antibodies against amyloid plques to the brain upon iv injection of the protein-transporter mixture was evaluated through staining for enzyme activity or micro single photon emission tomography (micro-SPECT) or immunostaining. Effect of the transporter on the integrity of the BBB was also investigated.Principal FindingsThe transporter enabled delivery to the mouse brain of functional beta-galactosidase, human IgG and IgM, and two antibodies that labeled brain-associated amyloid beta plaques in a mouse model of Alzheimer's disease.SignificanceThe results suggest the transporter is able to transport most or all proteins to the brain without the need for chemically linking the transporter to a protein. Thus, the approach offers an avenue for rapid clinical evaluation of numerous candidate drugs against neurological diseases including cancer. (299 words).

Effective Intravenous Therapy for Neurodegenerative Disease With a Therapeutic Enzyme and a Peptide That Mediates Delivery to the Brain

“…24 This approach differs from others in that, rather than functioning as part of a fusion protein, K16ApoE acts in trans in mediating delivery of target proteins across the BBB. We investigated whether coinjection of K16ApoE with TPP1 could promote uptake of the latter into the brain of the LINCL mouse.…”

“…14,19,21 We have recently described a peptide that can deliver target proteins across the BBB in a "mix and inject" strategy. 24 Intriguingly, this peptide works in trans and thus does not require covalent linkage with its target protein. Here, we demonstrate that this approach can achieve supraphysiological levels of TPP1 in the brain after IV administration to an LINCL mouse model.…”

The impact on the activity of acetylcholinesterase of a polylysine-ApoE peptide carrier targeting the blood brain barrier

“…With a demonstrated ability to transport compounds across the blood-brain barrier, this peptide has great potential (Sarkar et al, 2011(Sarkar et al, , 2014Meng et al, 2014Meng et al, , 2017 but, the toxicity of the peptide must be resolved. Although AChE is not the primary toxicity mechanism of action, it clearly plays a role.…”

“…A peptide carrier containing 16 polylysine residues and 20 amino acids of apolipoprotein E sequences (K16ApoE) has been demonstrated to deliver a variety of large protein therapeutics and small molecule drugs (Sarkar et al, 2011(Sarkar et al, , 2014. In a mouse model of Late-infantile neuronal ceroid lipofuscinosis (LINCL) with deficiency in the lysosomal protease tripeptidyl peptidase I (TPPI) (Sleat et al, 1997(Sleat et al, , 2004, we have achieved supraphysiological levels (~800% of wild-type) of intravenously-administered recombinant TPP1 throughout the brain upon co-injection with K16ApoE.…”

Photodynamic therapy in the treatment of intracranial gliomas: A review of current practice and considerations for future clinical directions

“…(9), can possibly be achieved for nanoparticlebased delivery, albeit due to their size (> 5 um) a temporary opening of the BBB may need to be realized. The latter can be achieved by injecting a salt solution, peptides as proposed by Sarkar et al 101 or locally the use of micro or nanoparticle-mediated ultrasound BBB disruption. 102 PDT research in gliomas, and more broadly other cancers, is following two di®erent approaches to increase the e±cacy of treatment.…”