In Vivo Use of a Multi-DNA Aptamer-Based Payload/Targeting System To Study Dopamine Dysregulation in the Central Nervous System

Abstract

The delivery of therapeutics across the blood-brain barrier remains a considerable challenge in investigating central nervous system related processes. In this work, a liposome vehicle was surface-modified with an aptamer that binds to the transferrin receptor and was loaded with two different dopamine-binding aptamer payloads. This system was effectively used to promote the delivery of the aptamer cargo from the peripheral injection site into the brain. The effect of these delivered aptamers on behavior was investigated in vivo in a locomotor task. The first dopamine binding aptamer assessed was a DNA aptamer, the binding of which had been previously validated through the aptamer-based biosensor development reported by several independent research groups. The second aptamer investigated was the result of a novel in vitro selection experiment described herein. Our data suggest that systemic administration of the modified liposomes led to delivery of the dopamine aptamers into the brain. Fluorescence microscopy revealed differential distribution of fluorescence based on the presence or absence of the transferrin receptor aptamer on the surface of fluorescently modified liposomes. In a behavioral experiment using cocaine administration to induce elevated concentrations of neural dopamine, systemic pretreatment with the dopamine aptamer-loaded liposomes reduced cocaine-induced hyperlocomotion. Multiple controls including a transferrin-negative liposome control and transferrin-positive liposomes loaded with either a nonbinding, base-substituted dopamine aptamer or a random oligonucleotide were investigated. None of these controls altered cocaine-induced hyperlocomotion. Chronic systemic administration of the modified liposomes produced no deleterious neurobehavioral or neural degenerative effects. Importantly, this work is one example of an application for this versatile multiaptamer payload/targeting system. Its general application is limited only by the availability of aptamers for specific neural targets.

Electrochemical Detection of Dopamine Based on Functionalized Electrodes

“…However, given the selectivity of the proposed method, it should be possible to accurately detect dopamine in more complex solutions, such as cerebrospinal fluid, or in the presence of different molecules or experimental conditions. Moreover, the use of aptamers, based on DNA and RNA, could greatly improve the selectivity of our electrodes because their selection is carried out by an evolutionary process of systematic evolution of ligands by exponential enrichment (SELEX), leading to very specific aptamers with low dissociation constants [47]. Despite the length and the cost associated with this selection, this strategy could be used to improve the electrodes described in this manuscript.…”

Advancements in Canadian Biomaterials Research in Neurotraumatic Diagnosis and Therapies

“…Aptamers have excellent molecular recognition abilities that make them uniquely suited for drug delivery, diagnostic, and therapeutic applications [9,10]. Using systematic evolution of ligands by exponential enrichment (SELEX), DeRosa et al developed and studied different aptamers for a variety of molecular targets, including neurotransmitters, cancer biomarkers, and viruses [11,12], and further developed aptamer-based MRI and computed tomography (CT) contrast agents by conjugating the aptamers and the contrast agents (as seen in Figure 1) for detection of intercranial thrombus in neurotraumatic patients [13,14]. Current research efforts are focused on developing new aptamer-based contrast agents to image fibrin in attempts to localize intercranial blood clots for early detection, as clinical treatment options for intercranial blood clots and prevention of their complications are highly dependent on early detections [15].…”

Aptamer Chimeras for Therapeutic Delivery: The Challenging Perspectives

“…Based on the work done in early 2000 by Shi et al, who exploited the RMT to transport cargoes through the BBB [ 97 ], DeRosa et al now adapted a similar strategy to deliver a DBA payload into the brain [ 102 ] by using the TfR, which is highly expressed on endothelial cell surfaces and has long been reported to mediate transcytosis of therapeutic protein ligands through the BBB. Brain-penetrating bispecific therapeutic antibodies in which the anti-TfR antibody has been conjugated to a therapeutic antibody for the β-secretase enzyme have been reported showing that a lower binding affinity for TfR was more favorable than that of a high affinity antibody [ 83 , 84 ].…”

“…Brain-penetrating bispecific therapeutic antibodies in which the anti-TfR antibody has been conjugated to a therapeutic antibody for the β-secretase enzyme have been reported showing that a lower binding affinity for TfR was more favorable than that of a high affinity antibody [ 83 , 84 ]. In their work, DeRosa et al used a short DNA aptamer ligand for the TfR to induce RMT that was conjugated to the surface of PEGylated liposomes as carrier to drive DBA-payload across the BBB [ 102 ]. The approach adopted in which aptamers were used as both the transport mediator and payload was effective to promote the delivery and of the functional dopamine aptamer ligands from the peripheral injection site into the brain.…”