Research Grants 2023-2024

Applicant
Institution
Title
Award
Dr. Yun Li
Hospital for Sick Children
Toronto, ON
Investigating MTOR hyperactivation related autism spectrum disorder in human stem cells derived neurons and brain organoids
2023/2024: $40,000
2024/2025: $40,000
2025/2026: $40,000
Dr. Jessica Rosin
University of British Columbia
Vancouver, BC
Studying the role microglia play in mediating neurodevelopmental responses to maternal sleep disruption
2023/2024: $40,000
2024/2025: $40,000
2025/2026: $40,000
Dr. Qiumin Tan
University of Alberta
Edmonton, AB
How to build an attractive cell body – Regulation of subcellular synaptic specificity
2023/2024: $40,000
2024/2025: $40,000
2025/2026: $40,000
Dr. Anastassia Voronova
University of Alberta
Edmonton, AB
Contribution of aberrant myelination to neurodevelopmental disorders
2023/2024: $40,000
2024/2025: $40,000
2025/2026: $40,000
Click on the Research Grant Title to view a brief description of Currently Funded Research Grants below


A Brief Description of Currently Funded Research Grants 2023 – 2024


 

Investigating MTOR hyperactivation related autism spectrum disorder in human stem cells derived neurons and brain organoids

Dr. Yun Li
Hospital for Sick Children
Toronto, ON

Introduction: Mutations in the PTEN gene are strongly associated with autism spectrum disorders (ASDs). Affected patients have key ASD symptoms including intellectual disability, macrocephaly, and epilepsy. Biochemically, PTEN is a negative regulator of the mechanistic target of rapamycin (MTOR) pathway, which is known to play crucial roles in controlling proper cellular growth. Specifically, MTOR functions in two structurally and functionally distinct complexes, MTORC1 and MTORC2. In cells with PTEN mutations, both MTORC1 and MTORC2 pathways are abnormally hyperactivated. Interestingly, animal studies showed that drugs such as rapamycin can inhibit both MTORC1 and MTORC2, and can rescue brain phenotypes of Pten mutant mice. However, rapamycin (and its derivatives) is not suitable for long-term treatment in ASD patients because it is a strong immune suppressant. Nevertheless, these animal studies suggest the exciting possibility that more specific inhibitors against MTORC1 or MTORC2 pathway can be effective therapy for ASD patients with PTEN mutations.

However, a crucial knowledge gap that prevents the design of effective treatment is not knowing whether MTORC1 or MTORC2 pathway is responsible for PTEN-related ASDs. Recent studies using Pten mutant mice reported highly conflicting findings. Whereas one study reported that MTORC2 hyperactivation causes most of the Pten mutant phenotypes, two others argued that MTORC1 is the main responsible pathway. This lack of consensus knowledge in animal models highlights an urgent need for mechanistic insights directly from disease relevant human neural cells.

Objective: In the current proposal, we will use human pluripotent stem cells (hPSCs)-derived neurons and brain organoids to investigate how PTEN mutation impacts human neural development and function in vitro. In particular, we will investigate whether inhibiting MTORC1 or MTORC2 can rescue disease relevant neural phenotypes. Combining breakthrough technologies in hPSCs, CRISPR editing, directed neural differentiation, and 3D brain organoids, my group has previously reported that PTEN mutant human brain organoids recapitulate the disease-relevant macrocephaly phenotype (Cell Stem Cell 2017). In unpublished results, we found that PTEN mutant human neurons have altered morphology and increased electric activity. These human cellular tools and novel insights put us at a uniquely advantageous position to systematically investigate the molecular mechanism of PTEN-related ASDs, and to explore therapeutic strategies.

Outline of research: In Aim 1, we will investigate how MTORC1 and MTORC2 contribute to cellular overgrowth and electric hyperactivity in PTEN mutant human neurons. We have created double mutant neurons that lack PTEN and an obligatory component of either MTORC1 or MTORC2 (RPTOR or RICTOR, respectively). In these double mutants, we can examine which one of the two pathways is important for the PTEN mutant phenotypes. Because small molecule inhibitors for these pathways have been developed for cancer treatment, we will also evaluate whether pharmacological inhibition of MTORC1 or MTORC2 downstream components can rescue PTEN mutant human neurons. In Aim 2, we will extend our genetic and pharmacological inhibition studies to human brain organoids, and investigate how MTORC1 and MTORC2 contribute to the macrocephaly phenotypes of PTEN mutant organoids. To date, we have generated the single and double mutant human stem cell lines necessary for these experiments. Our promising initial data strongly supports the feasibility and potential impact of the planned investigation.

Projected benefits and application of findings: Our proposed research addresses a major knowledge gap in ASD research. Understanding how MTOR hyperactivation alters human neural development and function will provide crucial insights into how to treat PTEN-related ASDs. The potential impact of our experimental platform and mechanistic insights goes beyond PTEN-related ASDs. MTOR hyperactivation is known to cause neurodevelopmental disorders such as Tuberous Sclerosis, Focal Cortical Dysplasia, and has been mechanistically implicated in Fragile X syndrome, Neurofibromatosis type 1, and Shank2-related ASDs. Our proposed research, if successful, will provide novel insights into ASD etiology, and serve as the foundation for future mechanistic and therapeutic discoveries to prevent, delay, and reverse ASD disease progression.


 

Studying the role microglia play in mediating neurodevelopmental responses to maternal sleep disruption

Dr. Jessica Rosin
University of British Columbia
Vancouver, BC

Introduction: Circadian rhythms are 24-hour cycles that are part of the body’s internal clock and align our biological functions with the external environment. The suprachiasmatic nucleus—a bilateral structure located in the hypothalamus—is the central pacemaker of circadian timing, and regulates most circadian rhythms in our body. Sadly, misalignment of circadian rhythms is becoming commonplace, as sleep disturbances brought on by shift work, nighttime light pollution from technology, and other factors (e.g., stress, anxiety, etc.) are prevalent in modern society—with circadian disruptions showing strong links to pathological processes such as metabolic disorders and inflammation. Circadian disruptions have also been found to negatively impact reproduction in women, as shift work is associated with an increased risk of menstrual cycle irregularity, polycystic ovary syndrome, infertility, miscarriage, pre-eclampsia, and preterm delivery. However, there is a lack of literature examining the impact of maternal circadian disruptions experienced during pregnancy on fetal neurodevelopment.

Recent scientific literature shows a strong association between prenatal environmental perturbations and neurodevelopmental disorders (NDDs), suggesting that the intrauterine environment is critically sensitive to early life exposures. Interestingly, a common feature reported across different challenges is disruption of the immune system, suggesting that immune cells within the developing fetal brain—namely microglia—sense changes in the intrauterine environment, and respond by altering normal neurodevelopmental programs. However, the mechanism(s) by which fetal microglia communicate with neural cells to change their behaviours and alter neurodevelopment is understudied—especially in the context of maternal circadian disturbances.

To examine the impact of maternal circadian disruptions on fetal neurodevelopment, we established a mouse model of sleep disruption. Our findings suggest that maternal sleep disruption alters microglia localization and signalling in a sex-specific manner in the fetal hypothalamus—particularly in regions known to be involved in sociability and play. Social play is thought to be important for the development of social, cognitive, and emotional processes. The proper acquisition of social behaviours, including the ability to sense, interpret, and respond to social cues, is disrupted in a number of NDDs. Together, this highlights the need for further investigation of the impact of maternal circadian disruptions on fetal neurodevelopment and the long-term consequences on offspring behaviour.

Objective: Although our findings provide insight into how maternal sleep disruption may influence the developing brain, it remains unknown how male and female microglia respond differently to maternal sleep disruption, and the impact these changes have on the developing brain. Accordingly, the overarching objective of this proposal is to ascertain how maternal sleep disruption alters fetal microglial activities and the effect these changes have on neurodevelopmental programs and offspring behaviour. We will examine this across three aims:
Aim 1: To determine how maternal sleep disruption alters fetal microglia physiology.
Aim 2: To ascertain how maternal sleep disruption impacts neurodevelopmental programs.
Aim 3: To define the long-term consequences of maternal sleep disruption on offspring behaviour.

Outline of Research: In Aim 1, we will examine how maternal sleep disruption alters the microglial phenome (e.g., morphology, movement, phagocytosis, etc.) in the fetal hypothalamus using live-cell imaging.

In Aim 2, we will study how maternal sleep disruption impacts neurodevelopmental programs by extracting neural stem cells from the hypothalamus and studying their behaviour in culture using a neurosphere assay.

In Aim 3, we will determine if offspring exposed to maternal sleep disruption during pregnancy present with behavioural deficits by employing numerous behavioural tests.

Projected benefits and application of findings: These findings will help us understand how microglia impact neurodevelopmental programs in response to maternal sleep disruption. This is important, as furthering our understanding of the causes and underlying mechanisms involved in NDDs will allow us to identify vulnerable pathways for interventions to reduce these insults on the developing brain.


 

How to build an attractive cell body – Regulation of subcellular synaptic specificity

Dr. Qiumin Tan
University of Alberta
Edmonton, AB

Introduction: Proper wiring of the developing brain relies on nerve cells making correct contacts with other nerve cells, either in a specific brain region or on a particular part of the target nerve cells. These spatially confined connections form the roadmap of brain activity. The hippocampus of the brain is an excellent system to study how such a roadmap is constructed. The hippocampus has important roles in learning and memory formation, spatial navigation, and mood regulation. These functions depend on a precise connectivity roadmap. But how some of these connections are confined to certain parts of the target nerve cells is not well known. We have identified factors that help establish proper connections in the developing hippocampus and we ask:
1) How does one type of nerve cell properly connect to another type of nerve cell?
2) What happens if these connections go awry?

Objectives: We will investigate how certain factors promote the proper connections between nerve cells. We will also look at how altered connections may change animal behaviors.
Outline of research: We will first investigate how a secreted factor promotes abnormal nerve cell connections by assessing the location of its receptor (a protein that binds to the secreted factor to mediate a response) in the target nerve cells. We think that the receptor, triggered by the secreted factor, moves to the cell surface to produce extra connections. We will then determine if these abnormal connections are functional, and if so, whether they wreak havoc in the brain to cause behavioral defects in animals.
Projected benefits and application of fundings: This project will be impactful in Solving the Puzzles of the Mind in several ways. First, our study will lend new insight into hippocampus development. This is clinically relevant as the hippocampus is a key structure implicated in several hallmarks of neurodevelopmental disorders such as intellectual disability, autism, and epilepsy. Second, abnormal nerve cell connections have been associated with learning deficits and epilepsy, but the steps leading to such phenomena are unknown. Our study will be a major step forward in understanding the contributions of proper nerve cell connections to learning disability and epilepsy. Third, much headway has been made in understanding how nerve cells target to the correct brain region, but how they find the right part of the target cells is much less understood. Our study will advance our knowledge of the basis for brain wiring and cognitive functions.


 

Contribution of aberrant myelination to neurodevelopmental disorders

Dr. Anastassia Voronova
University of Alberta
Edmonton, AB

Introduction: Neurodevelopmental disorders originate prenatally, when neural stem cells build the brain by producing neurons and non-neuronal glial cells (astrocytes and oligodendrocytes) at the correct time, place and numbers. Neurons are the main signaling cell type, while oligodendrocytes generate myelin, an insulating material that coats neuronal axons and ensures efficient neuronal signal propagation. Myelin comprises the white matter of the brain.

The majority of studies to date have focused on the role of genes associated with neurodevelopmental disorders in neuron formation and/or function. Yet, recent reports highlight the importance of appropriate glial cell formation and function in the context of neurodevelopmental disorders: i) autistic children have abnormal myelin; ii) abnormal glial cell formation and/or myelination promotes schizophrenia-like behaviour, motor dysfunction and epilepsy; and iii) increasing myelination promotes motor skill learning, memory consolidation and rescues some atypical social behaviours in mice. These discoveries point to the importance of myelin plasticity as a potential therapy for neurodevelopmental disorders. However, before we develop myelinating therapies for neurodevelopmental disorders we must first determine the contribution of aberrant myelination to their pathology.

Objective: ANKRD11 (Ankyrin Repeat Domain 11) is the most frequently newly (de novo) mutated gene in monogenic neurodevelopmental disorders. It has been identified as “high priority” to understand the underlying pathology and drive novel therapeutic strategies. This proposal is focused on studying the role of ANKRD11 in myelination.

Outline of research: By using a mouse model that allows to delete Ankrd11 in desired cells and tissues, we have ablated Ankrd11 in neural stem cells that are destined to become astrocytes and oligodendrocytes. Oligodendrocytes are of specific interest as they produce myelin. Here, we will study the effect of Ankrd11 deficiency on oligodendrocyte and myelin development and subsequent effects on neuronal connectivity and function. Further, we will determine the molecular and cellular mechanism of Ankrd11-mediated oligodendrocyte development from neural stem cells. To achieve this, we will use a combination of cutting-edge techniques and gold standards in the field like transmission electron microscopy, optogenetics and single-cell RNA sequencing.

Projected benefits and application of findings: While the importance of myelin is appreciated in neurodegenerative disorders, we do not understand its contribution to neurodevelopmental disorder pathology and associated neuronal dysfunction. Our work on the role of Ankrd11 in myelination will advance our understanding of the fundamental glial mechanisms of neurodevelopmental disorders caused by ANKRD11 deficiency. The results will be presented to the scientific and medical communities as well as to families and caregivers affected by ANKRD11-related neurodevelopmental disorders. This will enable better genetic counselling and future translation into the clinic via amendment of clinical guidelines and hopefully development of therapeutics to restore myelination and neuronal function in children affected by the ANKRD11-related and similar neurodevelopmental disorders.