Bipolar disorder (BD) is associated with language disturbances such as speech pressure and poverty of speech. However, little is known about the neurophysiology underlying language deficits in BD. In a previous study, we extracted three functional brain networks (i.e., a linguistic processing network - LPN, default mode network - DMN, and motor response network - RESP) involved in the lexical decision (LD) task by manipulating the "word-likeness" of LD stimuli combined with a multivariate functional connectivity analysis in healthy adults. Here, we applied the same techniques to determine if these three networks could be extracted in people with BD. The BD patients (n = 25) were also compared to controls (n = 21) to assess possible difficulties in LD task performance and abnormal activity in the three functional networks in BD. There were no differences between BD patients and controls in their accuracy or reaction times in the LD task. We replicated our previous work in healthy subjects as we were able to separate the LPN from the DMN and RESP. LPN activity did not differ between the groups, which is in line with the lack of significant differences in LD task performance between BD and control. BD was associated with sustained activity in the RESP, which involves activations in left-dominant pre- and post-central gyri and juxtapositional lobule cortex, as well as bilateral activations in superior and inferior lateral occipital cortex, superior parietal lobule, and occipital fusiform gyrus. Impairment in RESP may be observed in any task and could potentially be a biomarker for BD.

Altered activity in functional brain networks involved in lexical decision in bipolar disorder

Background: Multiple sclerosis (MS) is characterised by widespread damage of the central nervous system that includes alterations in normal-appearing white matter (NAWM) and demyelinating white matter (WM) lesions. Neurite Orientation Dispersion and Density Imaging (NODDI) has been proposed to provide a precise characterisation of WM microstructure. NODDI maps can be calculated for neurite density index (NDI), orientation dispersion index (ODI), which estimate orientation dispersion and neurite density. Although NODDI has not been widely applied in MS, this technique is promising in investigating the complexity of MS pathology, being more specific than diffusion tensor imaging (DTI) in capturing microstructural alterations.Aims: We conducted a meta-analysis of studies using NODDI metrics to assess brain microstructural changes and neuroaxonal pathology in WM lesions and NAWM in patients with MS.Methods: Three reviewers conducted the literature search of four electronic databases (Medline, Embase, Scopus, and PubMed). We performed a random-effect meta-analysis. The extent of between-study heterogeneity was assessed with the I2 statistic. Funnel plots and Egger's tests were used to assess publication bias.Result: We identified 7 studies analysing 374 participants (202 MS, 172 controls). NDI in WM lesions and NAWM were significantly reduced compared to healthy WM. The standardised mean difference was -3.08 (95%CI -4.22 to (-1.95), p=<0.00001, I2=88%) and -0.70 (95%CI -0.99 to (-0.40), p=<0.00001, I2=35%) respectively. There was no statistically significant difference of ODI in MS WM lesions and NAWM compared to healthy controls. The standardised mean difference was -0.44 (95%CI -1.60 to (-0.71), p=0.45, I2=95%) for WM lesions and -0.46 (95%CI -2.07 to (-1.15), p=0.58,

Investigating microstructural changes in white matter in multiple sclerosis: A systematic review and individual participant data meta-analysis of neurite orientation dispersion and density imaging

Microglia are functionally dynamic brain immune cells known to adapt their morphology depending on their environment. These context-dependent morphologies are extensively measured to inform changes in function. However, current manual morphological analyses, while informative, are often time-consuming and fail to detect subtle differences in cell architecture. To solve these limitations, we tested the sensitivity of an open-source quantitative method to measure microglial morphology called Fractal Analysis, adapted into a manual analysis of cell perimeter and area. Using the automated FracLac Plugin (ImageJ), we calculated the fractal dimension (FD) and lacunarity (LA), complementary indices, of two sets of immunohistochemical stainings (fluorescent and non-fluorescent) of hippocampal microglia and infiltrating bone marrow-derived macrophages (BMDM) from healthy postnatal mice. By creating a macro, we were able to combine our manual methodology to the fractal analysis, and find that FD and LA were more sensitive to changes in morphology than measurements of area and perimeter. In our dataset, FD and LA were both significantly increased in microglia compared to BMDM, while only LA was significantly higher in microglia among the ventral compared to the dorsal part of the hippocampus, possibly indicating increased process ramification. The detection of these differences in healthy tissue emphasizes the diverse regional morphology of microglia compared with infiltrating immune cells, but also the sensitivity of this automated methodology to detect subtle morphological changes.

Testing available quantitative methods to analyze brain immune cell morphology

α-synuclein (α-syn) aggregation into insoluble deposits, referred to as Lewy bodies (LBs) is the paramount pathological hallmark of Parkinson's disease (PD) and related α-synucleinopathies. However, how these aggregates affect neuronal homeostasis leading to neurodegeneration remains elusive. This gap in knowledge is mainly due to the lack of proper cellular and animal models to undertake such investigations. We have addressed this limitation by developing a light-inducible protein aggregation system (LIPA). This application is based on the use of a mutant form of the Arabidopsis thaliana photoreceptor cryptochrome 2 (CRY2), which when stimulated with blue light, mutant CRY2 undergoes rapid, reversible and robust protein clustering or aggregation. The use of this application allows for real-time induction of α-syn inclusions formation with remarkable spatial and temporal resolution in both cell culture and in vivo paradigms. We used a gene therapy approach, based on the use of adeno-associated virus (AAV), to overexpress our LIPA system directly into the brains of naive mice. For the delivery of the blue light necessary for the induction of the aggregation and propagation of α-syn, we used implantable micro-devices developed by Amuza Inc. We report on the development of a light-inducible protein aggregation (LIPA) system that enables real-time induction of α-syn inclusion formation with remarkable spatial and temporal resolution in living cells. In vivo, LIPA-α-syn aggregates compromised the nigrostriatal transmission, induced dopaminergic neuronal loss and PD-like behavioral impairment. Our system provides a novel, dependable and invaluable tool to generate, visualize and dissect the role of protein aggregates in PD and possibly other neurodegenerative disorders.

Optogenetic-mediated spatiotemporal control of α-synuclein aggregation mimics Lewy body formation and triggers neurodegeneration

Parkinson’s Diseases (PD) is the second most common neurodegenerative disorder and is characterized by a preferential loss of dopaminergic neurons of the substantia nigra pars compacta. The cause of the disease remains unknown; however, it is thought that environmental factors may contribute to its development. Rotenone is a pesticide that blocks mitochondrial respiration in the Electron Transport Chain by inhibiting Complex I and has been identified as an environmental risk factor for sporadic PD. Here our goal is to develop strategies that can lead to the development of potential preventative measures against PD. Dacarbazine is a potential anti-PD drug that is known for its use in chemotherapy for skin cancer and was identified in a previous screen for neuroprotective agents against the disease. We hypothesize that Dacarbazine can relieve or reverse the effects of rotenone in Drosophila. We set up a study to analyze the effect of dacarbazine against rotenone-induced neurotoxicity using locomotion behavior as a measure of neuronal toxicity. We set up four conditions: rotenone only; rotenone combined with dacarbazine; dacarbazine only; and DMSO only as vehicle only control. Here we present our results in two paradigms: a first one in which we performed a brief chronic exposure to rotenone and/or dacarbazine for three weeks and a second paradigm in which the chemical treated flies were allowed to recover on normal food for two additional weeks. Together, these studies could help determine whether dacarbazine confers protection against rotenone-induced neurotoxicity and could inform future efforts to establish a neuroprotective strategy against sporadic PD.

Ameliorating the effects of an environmental toxin in a Drosophila model of Parkinson’s Disease

Parkinson’s Disease (PD) is a common neurodegenerative disease. Although not fully understood, we do know that the alpha-synuclein protein plays a major role in causing PD. α-syn Drosophila flies overexpress the α-syn protein which it normally does not express. This allows it to be used as a model for studying Parkinson’s Disease. Gal4 is a driver that allows for the expression of α-syn. For this project, a cross of GAL4 Drosophila and α-syn Drosophila was compared to two control groups to develop a model. One control group was Gal4 crossed into wild-type background. The second control group was UAS-aSyn crossed into wild-type background. To develop the different variations, female drosophila were collected and crossed with adult male drosophila. Over a period of 8 days, the first generation offspring from the three groups were collected and divided into flies separated by sex. We ran locomotion assays using MWT (Multi-Worm Tracker) to track the movement of the flies. The males appeared to be moving at a slower rate than the females. We recorded survival, tracking the number of flies in each vial twice a week. On the 6th week of survival, there was a dramatic drop in the number of flies. Also, both female and male GAL4 x A-SYN Drosophila had similar survival rates. Once we develop a model we will use the model to run an experiment using PFF (Preformed Fibrils) to essentially test whether or not the overexpression of the α-syn gene protects the drosophila from getting Parkinson’s.

The Development of a Model to Study Genetic Parkinson’s Disease using Alpha-synuclein overexpressing Drosophila

Parkinson’s disease (PD) is the most prevalent neurodegenerative motor disease, mostly occurring in people over the ages of 65 years. Protein aggregation known as Lewy body is the hallmark for dopaminergic neuronal death in Parkinson’s disease pathology(1). PD patients initially experience motor deficits such as tremors and postural instability. As the disease progresses, patients lose complete control of physiological functions, which ultimately causes death. The current drugs available for the treatment of PD only alleviates the symptoms by boosting dopamine levels, but do not halt neurodegeneration. The main objective of this study is to evaluate the efficacy of a novel compound-6 by AptaBio as a potential therapeutic for Parkinson’s disease treatment. We analyzed whether this compound was efficacious in reducing PFF (Preformed fibrils of alpha-synuclein)-induced toxicity in N27 dopaminergic cells(3). The compound-6 not only enabled to increase cell viability and reduce cytotoxicity in vitro, but also reduced oxidative stress and minimized protein aggregation. We first tested the compound using a transgenic mouse model known as line 61(3). We demonstrate that the compound-6 successfully decreased motor deficits with stabilizing the levels of dopamine. However, we wanted to use an in vivo model that was more suitable to showcase the compound’s capability of halting neurodegeneration. Hence, we chose to use the PFF injected mouse model. Sonicated PFF was stereotaxically injected to the striatum of C57BL/6 male and female mice bilaterally (aged around 12 months). The PFF injection increases the phosphorylated alpha-synuclein and causes protein aggregation(2). After 4 to 5 months post injection, mice started showing Parkinsonian symptoms in behavior. At this stage, we gavaged the mice with the AptaBio compound-6 at two different doses of 5mg/kg and 25 mg/kg for 5 weeks. After gavaging we performed multiple behavioral tests such as hindlimb clasping, pole test, rotarod, nesting and grooming to measure whether motor function improved with the treatment as compared to PFF injected group that wasn’t treated. There was another group that was only injected with PBS, which was considered as positive controls since they do not show any motor deficits. Currently, we have finished all the behavioral tests and are finishing up data analysis for next 2 weeks. Taken together, our results are promising to show that the AptaBio compound-6 can be a novel and effective treatment for PD by halting neurodegeneration and promoting neuronal recovery.

AptaBio Compound-6 As a Potential Therapeutic for Parkinson’s disease models

Jasmine Sanchez Abstract Title: Genetic interaction between endu-2 and rnh-2 reveals their roles in neurogenesis in Caenorhabditis elegans RNase H2 is a ribonuclease/DNA repair factor that removes ribonucleotide leftovers from DNA. RNase H2 is essential for neurogenesis in animals. Mutations in the human RNase H2 genes cause Aicardi-Goutières syndrome, a severe and fatal neurological disorder. Dr. Ii’s research group found that mutations of C. elegans rnh-2 gene, which encodes the catalytic subunit of RNase H2, cause neuronal defects and behavioral changes. Endoribonuclease ENDU-2 plays a role in neurogenesis in nematodes and negatively regulates cold tolerance via apoptotic genes and the ADL neurons in C. elegans. Both endu-2 and rnh-2 are important for developing healthy neurons, but the relationship between these two genes is entirely unknown. C. elegans is a model organism widely used in Biomedical Research. A hermaphrodite has only 302 neurons and all of which corresponding behaviors have been identified. The power of C. elegans genetics has held the key to deciphering essential concepts in neuroscience and biomedicine for many years. In Aim 1, I performed 2 genetic crosses between the endu-2 mutant and the two rnh-2 mutants to isolate two different double mutants. Despite neither single mutant display sickness, we found synthetic lethal interactions between the mutations of these genes. Based on the results, the mechanism of the synthetic lethality appears to be due to accumulation of partial pathway defects in the same pathway. In Aim 2, I conducted “gene knockdown” using RNAi technique. We found that endu-2 gene knockdown moderately impaired the worm’s development, whereas rnh2 gene knockdown severely impaired the development and significantly increased its death rate. Surprisingly, an additional endu-2 knockdown reduced the severe defects of the rnh-2 single knockdown. This implies that endu-2 gene knockdown partially suppressed the defects caused by rnh-2 knockdown, suggesting endu-2 and rnh-2 function in the same pathway for neurogenesis.

Genetic interaction between endu-2 and rnh-2 reveals their roles in neurogenesis in Caenorhabditis elegans

Alcohol exposure (AE) during pregnancy is known to affect fetal medial prefrontal cortex (mPFC) and hippocampus (HC) development. Previous work has demonstrated that these two structures are vulnerable to AE during the brain growth spurt, which occurs during 3rd trimester of human pregnancy and the first two postnatal weeks in rodents. Our lab has shown that thalamic nucleus reuniens (Re) is damaged in a rodent model of human 3rd trimester AE. We have also shown that Re is critical for mPFC–HC oscillatory synchrony and spatial working memory (SWM). The current study investigated the effects of early AE on SWM ability in adulthood in rats. We predicted that AE would lead to SWM impairment that worsened as working memory demand increased. We administered 5.25 g/kg/day of ethanol in milk formula via intragastric intubations in a binge manner on PD 4-9 (AE group) or performed intubations without liquid (sham intubated (SI) group). On PD90, rats were trained on a continuous alternation (CA) T-maze task. Upon reaching a choice accuracy criterion of 80% for two consecutive days on CA, we introduced a delay between trials (DA) in order to increase SWM demand. The rats underwent 6 DA sessions, consisting of 12 each of 10-second (s), 30 s, and 60 s delay trials given in a pseudorandom sequence. Our results show that animals in both AE and SI groups learned the CA task at similar rates. However, on the DA task, the SI group showed consistent improvement across sessions on the 30-s delay trials, whereas the AE group did not (postnatal - treatment x day interaction: F(5,195)=2.70, p = .02). For the 10 s delay trials, both AE and SI groups showed improvement across days (main effect of day: F(5,195)=7.93 , p < .001), whereas for the 60 s delay trials, both groups performed uniformly poorly across days. These findings support the hypothesis that binge AE during the brain growth spurt produces SWM deficits that depend on SWM demand. This study will lead to a better understanding of the impact of HC-Re-mPFC circuitry damage due to developmental AE on cognitive function later in life.

Delay-dependent spatial working memory deficits in a rat model of third trimester alcohol exposure.

Parkinson’s Disease (PD) is the second most common neurodegenerative disorder in which dopaminergic neurons are lost. The cause of PD is still unknown; however, it is believed that environmental factors may contribute to the development of PD. Rotenone is a pesticide that blocks mitochondrial respiration in the Electron Transport Chain by inhibiting Complex I. Rotenone is an environmental risk factor for sporadic PD. Here we intend to develop strategies that can lead to the development of potential preventative measures against PD. In this project, Rotenone will be mixed in fly food to analyze its effects in adult Drosophila melanogaster in terms of behavior and longevity. Dacarbazine is a possible anti-PD drug that is known for its use in chemotherapy for skin cancer. We hypothesize that Dacarbazine can help ameliorate or reverse the effects of Rotenone in Drosophila. We will set up a study to analyze the effect of Rotenone, Dacarbazine, and a mixture of the two. There will also be a control group that we will use to compare our findings to. The compounds will be mixed in the fly food and fly activity will be under observation. Ultimately, we plan to establish research that shows that Dacarbazine is a potential neuroprotective chemical against a model of PD.

Acetylcholine (ACh) is one of the most abundant neurotransmitters in a human. It works in the central and peripheral nervous systems. In addition to its major role in neuromuscular junctions, ACh functions in memory and cognition in the brain. It is known that many Alzheimer’s disease patients have lower levels of acetylcholine. RNase H2 is a ribonuclease that removes ribonucleotides from DNA. It is also involved in gene expression. Although the full scope of this enzyme’s role in vivo is not fully known, it is a well-known fact that mutations in the RNase H2 genes in humans causes Aicardi- Goutières syndrome (AGS), a severe neurological disorder characterised by abnormal neurology and different types of encephalopathies. C. elegans is a nematode and model organism that has been widely used in Biomedical Research. Not only are they easy to work with and have quick generation times that allow for efficiency in research, but the organism also share more than 80% of their genes with humans. The purpose of this study was to determine, using the organism C. elegans, the effects of a mutation in the RNase H2 gene on cholinergic neurotransmission and the associated behaviours. RNase H2 S114F mutant worms were examined in time course experiments in the presence of ACh in the medium and their behaviours were compared to those of wild-type worms. The specific behaviour I observed were locomotion, pharyngeal pumping, and defecation. I found that the rnh-2 S114F mutation significantly affected all these behaviours in which cholinergic neurotransmission is involved. These results suggest that RNase H2 plays an important role in regulation of cholinergic neurotransmission and associated behaviours in C. elegans.

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Altered activity in functional brain networks involved in lexical decision in bipolar disorder

Investigating microstructural changes in white matter in multiple sclerosis: A systematic review and individual participant data meta-analysis of neurite orientation dispersion and density imaging

Testing available quantitative methods to analyze brain immune cell morphology

Optogenetic-mediated spatiotemporal control of α-synuclein aggregation mimics Lewy body formation and triggers neurodegeneration

Ameliorating the effects of an environmental toxin in a Drosophila model of Parkinson’s Disease

The Development of a Model to Study Genetic Parkinson’s Disease using Alpha-synuclein overexpressing Drosophila

AptaBio Compound-6 As a Potential Therapeutic for Parkinson’s disease models

Genetic interaction between endu-2 and rnh-2 reveals their roles in neurogenesis in Caenorhabditis elegans

Delay-dependent spatial working memory deficits in a rat model of third trimester alcohol exposure.

Ameliorating the effects of an environmental toxin in a Drosophila model of Parkinson’s Disease

The role of RNase H2 in cholinergic neurotransmission in Caenorhabditis elegans

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