In medical field today, current diagnostic tools for neurodegenerative diseases fail to diagnose patients prior to the occurrence of damaging neuronal loss. Oftentimes, this means that by the time a patient has been diagnosed with a disease such as Alzheimer's disease (AD) or Parkinson's disease (PD), they have already suffered severe, irreversible neurodegeneration. One of the significant weaknesses in the diagnosis and treatment of patients with AD and PD is the lack of viable biomarkers. Biomarkers are vital tools that can be utilized to identify patients who are in presymptomatic stages of a disease, track and quantify disease progression, and also determine whether or not a patient is responding to a particular treatment. RNAs are involved in all cellular processes, and due to their very specific spatial, temporal, and even cellular-level expression, abnormal expression signatures serve as key indicators of many diseases. Recently, cells have been shown to secrete nanometer-sized microvesicles, called exosomes, which moderate the horizontal transfer of mRNAs and miRNAs between cells. We hypothesize that exosomes obtained from human biofluids, such as cerebral spinal fluid (CSF) and blood plasma, can be used to determine extracellular RNA (exRNA) expression signatures associated with neurodegenerative disease. This experiment used pooled samples of CSF and plasma in order to investigate which of 3 sample enrichment methods would be most conducive to studying exRNA contained within exosomes. The results from this preliminary investigation will be used in later investigations that will seek to determine exRNA biomarkers of neurodegenerative disease.

The Dorrance Center for Rare Childhood Disorders is a unique research division at TGen (The Translational Genomics Research Institute) that provides personalized care to children and young adults facing rare, undiagnosed diseases. TGen scientists believe that the answers to these enigmatic disorders can often be found in a person's genetic code. They aim to solve these genetic mysteries using whole exome sequencing, a method that prioritizes the protein-coding portion of the genome in the search for disease-causing variants. Unfortunately, a communication gap sometimes exists between the TGen scientists and the patients they serve. I have seen, first hand, the kind of confusion that this study elicits in the families of its participants. Therefore, for my thesis, I decided to create a booklet that is meant to provide some clarity as to what exactly The Dorrance Center for Rare Childhood Disorders does to help diagnose children with rare disorders. The purpose of the booklet is to dispel any confusion regarding the study by providing a general review of genetics and an application of these lessons to the relevant sequencing technology as well as a discussion of the causes and effects of genetic mutations that often times are linked to rare childhood disorders.

A single splice site mutation in the mitochondrial methionyl-tRNA formyltransferase (MTFMT) gene is described in three patients with mitochondrial disease from two unrelated families. Nuclear-encoded MTFMT localized to the mitochondria is responsible for the formylation of Met-tRNAMet necessary for the initiation of translation in the mitochondria. This mutation has been associated with mitochondrial disease (oxidative phosphorylation deficiencies due to a decreased expression of MTFMT), Leigh syndrome, and developmental delay. However, there is significant phenotypic variation between patients, which is not uncommon in mitochondrial disease. Though the variation was not clearly elucidated through analysis of gene expression, this data supported two potential gene modifiers as well as proposed an alternative energy producing pathway in the cell—glutamine metabolism. This nonsynonymous mutation at site c.626C>T generates a splicing suppressor in the coding region on exon 4 resulting exon skipping in almost all transcripts in homozygotes during splicing. It is hypothesized that antisense oligotherapy will be effective in rescuing this mutation by inhibiting the splice silencer and promoting exon inclusion as well as an increased expression of MTFMT protein in affected patients. Patient fibroblast cells were treated with MTFMT Oligo 3, which was shown to be promising in previous experiments. Real-Time qPCR was used to measure mRNA expression showing a significant up-regulation of wild-type MTFMT with treatment. In order to test whether this therapy increases mitochondrial function as well, three mitochondrial functional assays measuring superoxide species in the mitochondria, the mitochondrial membrane potential, and calcium uptake in the mitochondria were tested for optimization of results. Success has been shown in the measurement of superoxide species and mitochondrial membrane potential in patient cells without treatment. Oligotherapy will hopefully be considered as a viable therapeutic option in the future as further testing is conducted and perfected.

Alzheimer’s disease (AD) is a progressive neurodegenerative disease that affects 5.4 million Americans. AD leads to memory loss, changes in behavior, and death. The key hallmarks of the disease are amyloid plaques and tau tangles, consisting of amyloid-β oligomers and hyperphosphorylated tau, respectively.

Rho-associated, coiled-coil-containing protein kinase (ROCK) is an enzyme that plays important roles in neuronal cells including mediating actin organization and dendritic spine morphogenesis. The ROCK inhibitor Fasudil has been shown to increase learning and working memory in aged rats, but another ROCK inhibitor, Y27632, was shown to impair learning and memory. I am interested in exploring how these, and other ROCK inhibitors, may be acting mechanistically to result in very different outcomes in treated animals.

Preliminary research on thirteen different ROCK inhibitors provides evidence that while Fasudil and a novel ROCK inhibitor, T343, decrease tau phosphorylation in vitro, Y27632 increases tau phosphorylation at a low dose and decreases at a high dose. Meanwhile, novel ROCK inhibitor T299 increases tau phosphorylation at a high dosage.

Further, an in vivo study using triple transgenic AD mice provides evidence that Fasudil improves reference memory and fear memory in both transgenic and wild-type mice, while Y27632 impairs reference memory in transgenic mice. Fasudil also decreases tau phosphorylation and Aβ in vivo, while Y27632 significantly increases the p-tau to total tau ratio.