Date of Award

Fall 11-2021

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Biomedical Engineering

First Advisor

Teresa Murray

Abstract

Here, the BBB-crossing ability of a Trojan horse peptide conjugated to a short therapeutic peptide was evaluated, with the aim to halt the progression of TBI-associated neuronal damage in a mouse experimental model of TBI. An associated study was also conducted to develop a new biosensor to probe hydrogen peroxide – a biomarker of chronic inflammation in the brain. The long-term goal of this study was to assess the regenerative or neuroprotective effect of this potential therapeutic peptide on neural disease pathology, thus expanding the known library of BBB-crossing peptides, and developing new tools for the study of inflammation, such as the biosensor used in this project.

First, the receptor-targeting peptides were designed and synthesized, followed by studying their uptake into different cell types of the BBB in vitro and quantifying the degree of the uptake. Subsequently, a therapeutic anti-inflammatory peptide was conjugated to the main peptide of interest, i.e., the Trojan horse peptide, and then its uptake was validated in vivo in mouse models of TBI. The focus was on executing this uptake via a non-invasive mode of administration i.e., intranasally, over a short, 7-day timeframe. The ultimate goal of this study was to test if this peptide conjugate could also cross the BBB and localize in the brain just as was demonstrated when studied by itself. Through histological analysis of TBI-injured, peptide-treated mouse brains, it was determined that the peptide localizes in the olfactory bulbs in the brain, regardless of whether the brain was injured. No evidence was found for localization in other brain regions in this preliminary study.

A new biosensor was developed in a collaborative project. It was shown to accurately sense acute oxidative stress in vitro through the detection of hydrogen peroxide in cultured mouse macrophage cells. This probe shows great promise in detecting hydrogen peroxide in an extracellular assay of inflammation in the future.

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