Canada Research Chair Research Articles

Toward practical aqueous zinc-ion batteries for electrochemical energy storage

Chang Li is a PhD candidate in the Department of Chemistry at University of Waterloo, under the supervision of Professor Linda F. Nazar. He received his bachelor's degree from the Department of Materials Science and Engineering at Huazhong University of Science and Technology in 2019. His current research focuses on developing novel electrolyte systems for Zn²⁺-exclusive intercalation cathodes and advanced anodes for aqueous zinc-ion batteries. Shuo Jin is a PhD candidate in the Smith School of Chemical and Biomolecular Engineering at Cornell University, under the supervision of Professor Lynden Archer. He received his bachelor's degree from South China University of Technology in 2018 and MS degree from Cornell University in 2020, both in chemical engineering. His current research focuses on understanding the effects of Zn electrodeposit crystallography on electrochemical reversibility of Zn anodes. Lynden Archer is the James A. Friend Family Distinguished Professor and Joseph Silbert dean of engineering at Cornell University. He is a member of the National Academy of Engineering and fellow of the American Physical Society and the Society of Rheology. His research focuses on fluid dynamics of simple and complex liquids at liquid solid interfaces, as well as their application for morphological control of battery anodes. Linda Nazar is a fellow of the Royal Society of London, an officer of the Order of Canada, and holds a Tier 1 Canada Research Chair in solid state energy materials. She was awarded the Materials Research Society Medal in 2020 for her outstanding contributions to advanced materials design, synthesis, and characterization for energy storage, particularly Li battery technologies. Dr. Nazar carries out research in solid state chemistry/ionics, electrochemistry, and materials chemistry and has published more than 270 academic papers. Dr. Nazar is identified as a highly cited researcher (Web of Science; 2014–2021), with multiple highly cited papers that are defined as those ranking in the top 1% by citations for chemistry.

Prevalence of suicidal ideation and self-harm behaviours in children aged 12 years and younger: a systematic review and meta-analysis

Suicide in children is a pressing public health concern. The increasing number of deaths by suicide and emergency visits for suicidal ideation and self-harm in children might not be fully representative; it is likely that many more children are in distress but do not seek out help. We conducted a systematic review and meta-analysis of existing studies to quantify the prevalence of suicidal ideation and self-harm behaviours among children in the community aged 12 years and younger. In this systematic review and meta-analysis, we searched PsycINFO, MEDLINE, and Web of Science via OVID from database inception to Feb 28, 2022, for articles published in French or English that reported estimates of prevalence of suicidal ideation (including suicide planning) and self-harm behaviours (namely, self-harm, suicide attempts, and non-suicidal self-injury) in children aged 12 years and younger. Reference lists were also searched; case studies, qualitative studies, and health-care visit studies were excluded. The outcomes were suicidal ideation, suicide plan or attempts, and self-harm. We used a random-effects model to calculate the overall pooled prevalence of suicidal ideation and self-harm behaviours for all timeframes combined and for ever versus the past 12 months for suicidal ideation. We used the Joanna Briggs Institute Critical Appraisal tool to evaluate the risk of bias in each study. This study is registered with PROSPERO, CRD42020179041. 28 articles, encompassing 30 studies overall, met the inclusion criteria, aggregating findings from 98 044 children (of whom 46 980 [50·5%] were girls and 46 136 [49·5%] were boys; six articles did not report sex or gender) aged 6-12 years. The pooled prevalence estimate was 7·5% (95% CI 5·9-9·6) for suicidal ideation from 28 studies and 2·2% (2·0-2·5) for suicide planning from three studies. The pooled prevalence was 1·4% (0·4-4·7) for self-harm from four studies, 1·3% (1·0-1·9) for suicide attempt from six studies, and 21·9% (6·2-54·5) for non-suicidal self-injury from two studies. The prevalence of suicidal ideation was higher in studies that included child-reported outcomes (10·9% [95% CI 8·1-14·5] for child only and 10·4% [6·8-15·5] for child and parent combined) than for parent-only reported outcomes (4·7% [3·4-6·6]; p=0·0004). The prevalence of suicidal ideation and self-harm behaviours was similar in boys and girls (suicidal ideation, 7·9% [95% CI 5·2-12·0] for boys vs 6·4% [3·7-10·7] for girls; self-harm behaviours, 3·5% [1·6-7·2] for boys vs 3·0% [1·4-6·4%] for girls). Detailed ethnicity data were not available. High heterogeneity was identified across estimates (I2>90%), which was not well explained by the characteristics of the studies. A high number of children in the general population can experience suicidal ideation and self-harm behaviours, thus underlining the need for more research on childhood suicide, including developmentally appropriate preventive strategies, such as youth-nominated support teams or dialectical behavioural therapy. Canada Research Chair in Youth Mental Health and Suicide Prevention.

Characterizing Liquid Water Distribution in Polymer Electrolyte Fuel Cells Using Operando 2D and 3D X-Ray Imaging

The potential to reduce the cost of Polymer Electrolyte Fuel Cells (PEFCs) through high power density operation is limited by the attending water management challenges at such operating conditions [1]. Addressing PEFC water management requires detailed understanding of liquid water distribution characteristics of an operating fuel cell, to refine the design of membrane electrode assemblies (MEAs) for improved performance.Recent advances in X-ray operando imaging [2, 3] and custom hardware development [4], have enabled the visualization of liquid water in an operating PEFC, through the analysis of water phase segmented 3-dimensional (3D) images [2, 3] and 2-dimensional (2D) radiographs [5]. 2D image datasets may be acquired in a shorter time than 3D tomographic datasets but only provide grayscale information averaged through the thickness of the sample. 3D image datasets obtained from a reconstruction of many angular radiographs yield a 3D representation of the sample in addition to the grayscale information but take a long collection time. However, time dependent liquid water distribution characteristics such as channel water breakthrough, observable in the 2D image datasets, tend to be elusive to 3D imaging methods. Although efforts have been made to reduce the image acquisition time for 3D X-ray imaging by using Synchrotron sources and improved image processing techniques [2], these efforts tend to compromise image quality and are restricted to a brief temporal snapshot of liquid water distribution. Also, the brightness of the Synchrotron sources necessitates short exposure duration tests due to the likelihood of cell degradation caused by the sample’s exposure to radiation [4]. Given the unique capabilities of 2D and 3D imaging modes, we therefore focus on combining information accessible in both modes to further the understanding of PEFC liquid water distribution.In this work, an improved understanding of liquid water distribution in the PEFC is presented by integrating operando 2D and 3D image datasets acquired under the same cell operating conditions and using laboratory scale X-ray computed tomography (XCT) equipment which was interfaced with fuel cell testing and diagnostic tools. Analysis of 3D image datasets is extended beyond binary information to include the grayscale value (GSV) of liquid water to reveal a change in the through-plane values. These results, when combined with observed 2D liquid water breakthrough characteristics suggest that the change in GSV is indicative of the differences in the intermittency of liquid water presence in the different regions of the GDL; see Figure 1. These results therefore present a more complete interpretation of PEFC operando liquid water distribution, highlighting distinct characteristics from the microporous (MPL) region to the GDL-land interface. Unique findings and insight obtained using this methodology will be discussed. Acknowledgments Funding for this research was provided by the Natural Sciences and Engineering Research Council of Canada, Ballard Power Systems, Canada Foundation for Innovation, British Columbia Knowledge Development Fund, Western Economic Diversification Canada, and Canada Research Chairs. References Jiao and X. Li, Progress in energy and combustion Science, vol. 37, no. 3, pp. 221–291, 2011.Xu, S. Nagashima, H. P. Nguyen, K. Kishita, F. Marone, F. N. Büchi, and J. Eller, Journal of Power Sources, vol. 490, p. 229492, 2021.Nagai, J. Eller, T. Hatanaka, S. Yamaguchi, S. Kato, A. Kato, F. Marone, H. Xu, and F. N. Büchi, Journal of Power Sources, vol. 435, p. 226809, 2019.T. White, F. P. Orfino, M. El Hannach, O. Luo, M. Dutta, A. P. Young, and E. Kjeang, Journal of The Electrochemical Society, vol. 163, no. 13, pp. F1337–F1343, 2016.R. Banerjee, N. Ge, J. Lee, M. G. George, S. Chevalier, H. Liu, P. Shrestha, D. Muirhead, and A. Bazylak, Journal of The Electrochemical Society, vol. 164, no. 2, p. F154, 2017. Figure 1

Polymer Electrolyte Fuel Cell Degradation Investigations Using X-Ray Computed Tomography

On-going research is aimed at commercializing low temperature fuel cell technology systems as zero emission alternatives for automotive applications in order to reduce greenhouse gas emissions and air pollution. These systems use polymer electrolyte fuel cells (PEFCs) to generate electricity via an electrochemical process using hydrogen and ambient air (oxygen) to produce water. Advantages of PEFCs include quick start-up time, low operating temperature, low weight, high efficiency, and relatively simple design. An important area of current research is the identification of factors which affect fuel cell performance degradation during operation and ultimately, its durability. A technique that has yielded new insights in the investigation and identification of failure modes in fuel cells is lab-based X-ray computed tomography (XCT), which is most advantageous due to its on-demand availability. The Fuel Cell Research Laboratory (FCReL) at Simon Fraser University currently operates Canada’s only facility for multi-length scale XCT, comprising of two state-of-the-art laboratory-based XCT scanners from Carl Zeiss X-ray Microscopy (Zeiss Xradia 520 Versa and 810 Ultra) with complementary resolution and field of view capabilities. This unique combination offers unprecedented access to investigations at multi length scales; with an ability to probe fuel cell components at the micro as well as the nano scale. Figure 1 illustrates the fuel cell holder and its orientation with respect to the X-ray beam as well as an exploded view of the miniature fuel cell design.An overview of recent fuel cell degradation investigations at FCReL using the XCT technique will be shown. The XCT based workflow facilitates determination and quantification of material structure and properties changes resulting from degradation stresses associated with operational parameters such as temperature, relative humidity, and voltage. The non-destructive nature of lab-based XCT visualization coupled with the ability to scan the same fuel cell multiple times without inducing damage [1] has enabled detailed studies of fuel cell degradation evolution in four dimensions (3D space, 1D time) [2 - 4]. The new knowledge gained from this procedure has led to root cause identification with respect to membrane and catalyst layer crack initiation and propagation [5 - 7], sealing issues [8,9], and subsequent mitigation toward enhanced fuel cell durability. Acknowledgement This research was supported by the Natural Sciences and Engineering Research Council of Canada, Canada Foundation for Innovation, British Columbia Knowledge Development Fund, Western Economic Diversification Canada, Canada Research Chairs, and Ballard Power Systems.

Simulation of Cathode Catalyst Durability Under Fuel Cell Vehicle Operation - the Effect of Fuel Cell Stack Size

The concerns regarding climate change have made the researchers seek a clean alternative for the fossil fuel vehicles. Fuel cell vehicles (FCVs) are considered to be promising candidates owing to their efficient energy conversion and zero-carbon emission. However, a number of obstacles such as high cost and limited hydrogen infrastructure have made the FCVs commercialization process challenging. Polymer electrolyte membrane fuel cells (PEMFCs) have been proven promising for transportation applications. For heavy duty transportation applications, the PEMFC durability is also not yet proven, and extrapolating from lab data to real-world field operating conditions remains a significant challenge [1].In this work, the cathode catalyst degradation in PEMFC is studied to estimate the effect of stack size on fuel cell durability in the FCV application. Platinum dissolution and redeposition, platinum oxidation and platinum ion formation during the fuel cell operation are modeled using the Butler-Volmer approach presented in [2]. A drive cycle recorded based on a real-life transit bus operation in the city of Victoria is utilized to calculate the input fuel cell voltage profile based on the methodology presented by Ahmadi and Kjeang [3]. According to this methodology, the required cell power density is calculated using Newton’s second law considering the air flow drag force as a counteracting force against the vehicle movement. Then, the required voltage cycle is obtained by employing a polarization curve characterizing the fuel cell performance. Finally, the change of remaining electrochemically active surface area (ECSA) with time is calculated as the output of the model. The fuel cell is assumed to operate at 80 ℃ and the cell active area is considered to be 500 cm2. Simple Tafel kinetics is then used to determine the fuel cell voltage loss. A 10% voltage drop at 0.6 A/cm2 is considered as the failure criterion for the cathode lifetime. Moreover, the effect of the fuel cell stack size is studied. By increasing fuel cell stack size, the required cell power density drops, leading to a decrease in the voltage cycle amplitude while the voltage cycle period remains the same. According to the empirical kinetic rate equation, the catalyst degradation exponentially increases with increasing the voltage. Therefore, a higher degradation rate is observed for a catalyst operating on a voltage cycle with a lower amplitude while the period and the upper potential limit (UPL) are maintained the same, causing a significant platinum ion generation. Fig. 1 shows the change of remaining ECSA over time and resulting fuel cell lifetime for three stack sizes which are represented by the stack nominal powers. The results show that the fuel cell lifetime will be roughly doubled when the stack size is reduced by half. Stack sizing is thus an important consideration for fuel cell durability in the FCV application.In this regard, predicting fuel cell lifetime is a crucial step in commercializing FCVs. The present modeling framework could be utilized by FCV developers to predict lifetime for new products instead of carrying out time-consuming lifetime experiments. The factors influencing fuel cell durability can also be investigated using the present model framework to develop durables cells and stacks for a targeted FCV application. Acknowledgements This research was supported by the Natural Sciences and Engineering Research Council of Canada, Canada Research Chairs, and Simon Fraser University Community Trust Endowment Fund.

290-OR: A Randomized Controlled Trial to Alleviate Carbohydrate Counting in Type 1 Diabetes with Automated Fiasp and Pramlintide Closed-Loop Delivery

We conducted a non-inferiority randomized crossover trial to alleviate carbohydrate counting (CC) in people with diabetes using automated dual-pump delivery of faster aspart (Fiasp) and pramlintide. Adults (N=15, 9 F, 39 ± 14 years, A1c 7.2 ± 0.9%) and adolescents (N=15, 8 F, 16 ± 1 years, A1c 8.4 ± 0.9%) used (i) Fiasp and placebo with CC, (ii) Fiasp and pramlintide with meal announcement (MA) , and (iii) Fiasp and placebo with MA for 2 weeks. Fiasp and pramlintide were delivered at a fixed 1 U:µg ratio to mimic a co-formulation. MA arms delivered fixed, user-specific priming meal boluses, independent of carbohydrate content. Prior to the first arm, participants had a 1-week run-in with automated Fiasp (single pump) delivery and CC, with mean time in range (70-180 mg/dL) of 71% in adults and 64% in adolescents. In adults, mean time in range was 65% on Fiasp and placebo with CC, 71% on Fiasp and pramlintide with MA, and 64% on Fiasp and placebo with MA; non-inferiority with a pre-defined 6.25% margin was achieved in both MA arms with pramlintide and placebo (difference -6 [95% CI -12.6, 0.5]; 1 [-3.0, 4.6]) . In adolescents, mean time in range was 51%, 55%, and 46% in the three respective arms; non-inferiority was only achieved on Fiasp and pramlintide with MA (-4 [-9.0, 1.7]) . We conclude that automated Fiasp and pramlintide delivery may alleviate CC without degrading glucose control. Disclosure E.Cohen: None. E.Palisaitis: Other Relationship; Eli Lilly and Company. J.Rutkowski: None. L.Legault: Advisory Panel; Abbott Diabetes, Insulet Corporation, Novo Nordisk A/S, Other Relationship; Eli Lilly and Company, Research Support; AstraZeneca, Merck & Co., Inc. A.Haidar: Consultant; Eli Lilly and Company, Research Support; ADOCIA, Dexcom, Inc., Eli Lilly and Company, Tandem Diabetes Care, Inc. M.Tsoukas: Speaker's Bureau; AstraZeneca, Bausch Health, Canada, Boehringer Ingelheim International GmbH, Eli Lilly and Company, Johnson & Johnson, Novo Nordisk Canada Inc. J.E.Von oettingen: None. J.Yale: Advisory Panel; Bayer AG, Boehringer Ingelheim International GmbH, Eli Lilly and Company, Novo Nordisk Canada Inc., Sanofi, Research Support; Bayer AG, Speaker's Bureau; Abbott Diabetes, AstraZeneca, Bayer AG, Dexcom, Inc., Eli Lilly and Company, Janssen Pharmaceuticals, Inc., Merck & Co., Inc., Novo Nordisk Canada Inc., Sanofi. N.Garfield: None. M.Vallis: Advisory Panel; Bausch Health, Canada, Novo Nordisk Canada Inc., Consultant; Abbott Diabetes, LifeScan, Speaker's Bureau; AbbVie Inc., Bausch Health, Canada, LifeScan, Novo Nordisk, Novo Nordisk A/S. N.Gouchie-provencher: None. A.Jafar: None. M.Ghanbari: None. Funding Juvenile Diabetes Research Foundation International (2-SRA-2018-654-M-B) , Canada Research Chairs

1396-P: Critical Cellular Functions That Mediate the Early Stages of Adipogenesis Are Directly Influenced by 14-3-3zeta and Its Interactome

Aim: We previously discovered that 14-3-3-zeta (14-3-3ζ) was essential for adipocyte differentiation. Although 14-3-3ζ scaffold is not a transcription factor (TF) , it undergoes nuclear translocation during adipogenesis. Considering its diverse interactome, we hypothesized that 14-3-3ζ anchors, nucleates and regulates essential transcriptional complexes required for adipogenesis. Methods: 3T3-L1 pre-adipocytes were modified by CRISPR-Cas9 to express a TAP (Flag-HA) -tagged 14-3-3ζ protein. At 48 first hours of adipogenesis, nuclear TAP-14-3-3-ζ complexes were purified to identify and annotate the 14-3-3ζ interactome by MS and Gene Ontology. Highly enriched proteins functions were assessed for their roles in adipogenesis using pharmacological inhibitors or siRNA. In parallel, chromatin accessibility was assessed by ATAC-Seq from control or 14-3-3ζ-depleted 3T3-L1 cells during early adipogenesis. Results: We found that the 14-3-3ζ nuclear interactome during the early stages of adipogenesis was significantly enriched with 133 proteins, including CEBP-β, an early adipogenic TF. According to GO analysis, proteins within the 14-3-3ζ interactome were primarily associated (FDR ≤ 0.01) with histone H2B ubiquitination, DNA unwinding for replication, DNA hypermethylation and ribosome assembly. Pharmacological inhibition or depletion by siRNA of these proteins significantly dampened adipocyte differentiation. Principal component analysis of ATAC-seq results revealed that samples from 14-3-3ζ-depleted cells differed from controls in term of whole chromatin accessibility, and DESeq2 identified nearly 3400 (p<0.05) differentially accessible regions of open chromatin following 14-3-3ζ depletion. Conclusion: These results reveal that via critical protein interactions, 14-3-3ζ has essential roles in chromatin accessibility, DNA replication, and mRNA translation, which are crucial events for the early adipogenesis. Disclosure S.A.Rial: None. A.Alkhoury: None. G.Lavoie: None. P.Roux: None. T.M.Durcan: None. A.Martinez-sanchez: None. G.E.Lim: None. Funding Natural Sciences and Engineering Research Council of Canada (NSERC) ; Canada Research Chairs (CRC) ; Fonds de recherche du Québec-Nature and Technologies (FRQNT)

Adipocyte Size, Adipose Tissue Fibrosis, Macrophage Infiltration and Disease Risk Are Different in Younger and Older Individuals with Childhood and Adulthood Onset Obesity

ObjectivesThe timing of obesity onset and age have been shown to affect the risk of obesity-related comorbidities, although the impact of each of these factors on markers of adipose tissue function remains unclear. The aim of this study is to determine whether differences in regional adipose tissue characteristics vary with age and age of obesity onset, and whether these differences are associated with the markers of cardiometabolic health.MethodsAdipose tissue samples were from 80 female bariatric surgery candidates who were classified by age of obesity onset and age into 4 groups: 1) younger adults (<40 y) with childhood-onset obesity (< 18 y) (Childhood-Young); 2) younger adults with adulthood-onset obesity (>18 y) (Adulthood-Young); 3) older adults (>55 y) with childhood-onset obesity (Childhood-Old); and 4) older adults with adulthood-onset obesity (Adulthood-Old). Adipocyte diameter, adipose tissue fibrosis and macrophage infiltration were determined in subcutaneous (SAT) and visceral adipose tissue (VAT). Clinical parameters were obtained from participants’ medical records.ResultsVisceral adipocyte size in the Childhood-Young group was the smallest of all the groups. Age affected visceral infiltration of M1-like cells in both older groups, whereas onset, specifically childhood-onset, was related to visceral infiltration of M2-like cells in the Childhood-Old group. Fibrosis accumulation in SAT and VAT varied with age and onset, particularly in the Childhood-Old group having the lowest fibrosis levels. Markers of cardiometabolic health (fasting glucose, glycated hemoglobin, total, HDL- and LDL-cholesterol and triglyceride concentrations) were positively and well associated with adipose tissue characteristics of the Childhood-Old group but not of the Adulthood-Young group.ConclusionsOlder adults with childhood onset obesity, who had the greatest duration of obesity exposure, were particularly vulnerable to the cardiometabolic effects associated with perturbations in adipose tissue characteristics. These results, suggest that age and age of obesity onset may have independent and cumulative effects on obesity pathology.Funding SourcesSylvia Santosa holds a Canada Research Chair – Tier 2 in Clinical Nutrition. This research is also supported by a Discovery Grant from The Natural Science and Engineering Research Council of Canada.

A Conversation with SMI 2021 Young Researcher Award winner Melina Skouras

The 2021 Shape Modeling International Young Researcher Award is presented to Dr. Melina Skouras for her significant contributions to shape modeling. For this award, the candidates must have received the their Ph.D. degrees within seven years of the award being presented.This year, 2021 is the year, which marks the passing of our founder, Professor Kunii, and the introduction of the new SMI awards. The SMI steering committee decided that the awardee’s publication should take an interview format. This permits a casual discussion of the research areas, insights, and contributions of the award winner. What follows is an edited transcript of a conversation between Melina and Brian Wyvill (University of Victoria, Professor and Canada Research Chair, retired), a long term SMI steering committee member and research contributor in shape modeling.The interview that took place on the 9th November, 2021, via Zoom.

A conversation with Bianca Falcidieno: SMI 2021 Tosiyasu Kunii Achievement Award winner

The 2021 Shape Modeling International Tosiyasu Kunii Achievement Award is presented to Dr. Bianca Falcidieno for her outstanding career achievements in shape modelling research. We are also pleased to honour her valuable service to the research community, recognizing the work she has put in as editor-in-chief of the International Journal of Shape Modeling, and the SMI conference series.This year, 2021 is the year, which marks the passing of our founder, Professor Kunii, and the introduction of the new SMI awards. Achievement awards in other venues, include a publication by the award winner to be included in the proceedings. The SMI steering committee decided that the publication should take an interview format. This permits a casual discussion of the research areas, insights, and contributions of the award winner. What follows is an edited transcript of a conversation between Bianca Falcidieno and Brian Wyvill (University of Victoria, Canada Research Chair), a long term SMI steering committee member and research contributor in shape modelling.The interview took place on the 22nd October, 2021, via Zoom.

Restriction of viral replication, rather than T cell immunopathology, drives lethality in MNV CR6-infected STAT1-deficient mice

Abstract Recent evidence indicates that viral components of the microbiota can contribute to intestinal homeostasis and protection from local inflammatory or infectious insults. However, host-derived mechanisms that regulate the virome remain largely unknown. Here, we used colonization of C57BL6/J mice with the model commensal murine norovirus (MNV CR6) to interrogate host-directed mechanisms of viral regulation, and show that STAT1 is a central coordinator of both viral replication and antiviral T cell responses. In STAT1-sufficient mice MNV CR6 is asymptomatic and restricted to the colon, despite the persistence of high viral loads. However, in the absence of STAT1 viral replication is disseminated and observed in key innate and adaptive immune populations. STAT1-deficient mice develop dysregulated inflammatory CD8+ and CD4+ T cell responses, which coincide with weight loss and severe necrosis of the spleen and liver. Despite these altered T cell responses which resemble those that mediate lethal immunopathology following other model viral infections of STAT1-deficient mice, depletion of adaptive immune cells and their associated effector functions had no effect on CR6-induced disease. In contrast, therapeutic administration of an antiviral compound limited viral replication, preventing viral-induced tissue damage and death despite ongoing inflammatory antiviral T cell responses. Collectively, our data show that STAT1 restricts MNV CR6 replication within the intestinal mucosa. Unlike other model viral infections, CR6 induces disease in STAT1-deficient mice via uncontrolled viral replication rather than the concomitant development of dysregulated antiviral T cell responses. Research in the Osborne lab is supported by the Natural Sciences and Engineering Research Council of Canada, the Canadian Institutes of Health Research, the Canada Research Chair program and scholarships from the University of British Columbia.

A dietary fiber limits autoimmune neuroinflammation by restricting Th1 activation, polarization, and migration

Abstract Dietary fibers and their breakdown products have been shown to limit inflammation in multiple disease contexts. However, the term “dietary fiber” encompasses a biochemically diverse family of carbohydrates, and it remains unknown how different fiber sources influence immune cell function. To address this question, we assessed the immunomodulatory capacity of different fiber types in a mouse model of multiple sclerosis, experimental autoimmune encephalomyelitis (EAE). C57BL/6 mice were fed a control diet (5% cellulose) or diets enriched (30%) with resistant starch, inulin, pectin, or guar gum for 2 weeks prior to EAE induction. A diet rich in guar gum uniquely ameliorated the clinical, pathological, and immunological features of EAE. Limited central nervous system (CNS) infiltration of IFNγ+CD4+ T cells (Th1s) in guar gum-fed mice could be attributed to T cell-intrinsic impairment Th1 activation and polarization. Nanostring nCounter transcriptional analyses revealed downregulation of migration-associated markers in CD4+ T cells isolated from guar gum/EAE mice, which was supported by reduced cell-surface expression of integrins involved in migration into the CNS. Functionally, this translated to limited migration of guar gum-derived encephalitogenic Th1s into the CNS upon adoptive transfer into control-fed recipients, which reduced incidence and severity of EAE. However, the 16S rRNA microbiome signature and short chain fatty acid profiles were not unique in comparison to other fiber-supplemented diets, indicating a novel mechanism of action from those previously ascribed in high fiber diet studies. These data confirm the individuality of dietary fibers and identify a novel immunomodulatory function of guar gum. This project was supported by the endMS doctoral studentship program (Multiple Sclerosis Society of Canada) (NMF, JRA), the Canadian Institutes for Health Research (PJT-148909), and the Canada Research Chair program (LCO).

The X-linked gene for the helicase DDX3X is required for lymphoid differentiation and MYC-driven lymphomagenesis

Abstract The X-linked gene DDX3X encodes an RNA helicase and is mutated at high frequencies in several types of human B-cell lymphoma. Females have two active DDX3X alleles and males carry a DDX3Y homolog on the Y chromosome. We show here that pan-hematopoietic, homozygous deletion of Ddx3x in female mice perturbs erythropoiesis causing early developmental arrest. However, both hemizygous male and heterozygous female embryos develop normally, suggesting that one Ddx3x allele is sufficient for fetal hematopoietic development in females and that the Ddx3y allele can compensate for the loss of Ddx3x in males. In adult mice, loss of DDX3X affects hematopoietic progenitors, early lymphoid development, marginal zone and germinal center B-cells and lymphomagenesis driven by an Em-Myc transgene in a sex-dependent manner. Loss of one Ddx3x allele slightly accelerated MYC-driven lymphomagenesis in female mice, while male Em-Myc mice lacking Ddx3x remained almost lymphoma-free. However, the few tumors that appeared in male mice showed upregulated expression of DDX3Y indicating a minimal requirement for DDX3 activity for lymphomagenesis. Our data reveal sex specific roles of DDX3X in erythro- and lymphopoiesis as well as in MYC-driven lymphomagenesis, which are important when considering inhibition of DDX3 as a treatment of B-cell lymphoma. Tarik Möröy holds a Canada Research Chair (Tier 1), a Foundation grant from the CIHR (FDN-148372) and support from the Cancer Research Society (CRS). Marion Lacroix is supported by fellowships from the Cole Foundation and the IRCM.

Editorial introductions.

Current Opinion in Cardiology was launched in 1985. It is part of a successful series of review journals whose unique format is designed to provide a systematic and critical assessment of the literature as presented in the many primary journals. The field of cardiology is divided into 14 sections that are reviewed once a year. Each section is assigned a Section Editor, a leading authority in the area, who identifies the most important topics at that time. Here we are pleased to introduce the Section Editors for this issue. SECTION EDITORS Subodh VermaSubodh VermaDr Subodh Verma is an internationally renowned cardiac surgeon-scientist and Professor at the University of Toronto, Canada. He is the Canada Research Chair in Cardiovascular Surgery and a past recipient of the Howard Morgan Award for Distinguished Achievements in Cardiovascular Research and the Royal College of Physicians and Surgeons of Canada Gold Medal in Surgery. He previously served as the Canada Research Chair in Atherosclerosis from 2007–2017. He is an appointee of the American Association of Thoracic Surgeons (AATS) and a member of the College of New Scholars, Artists and Scientists, Royal Society of Canada. According to Google Scholar in December 2020, Dr Verma has an h-index of 107 and his work has been cited over 58,000 times. Dr Verma has published extensively in prestigious journals like the NEJM, Lancet, Circulation, JACC, Nature, and JCI and he is currently an Associate Editor of the European Heart Journal. Dr Verma is an active contributor to Canadian clinical practice guidelines and recently co-authored the recommendations for atrial fibrillation, antiplatelet therapy, heart failure and diabetes; he was a member of the 2018 AATS consensus guidelines committee on bicuspid aortic valve-related aortopathy. Dr Verma has served in various capacities on the American Heart Association Council on Cardiovascular Surgery and Anesthesia since 2008. Dr Verma has leadership roles on seven global heart failure trials in diabetes – DAPA-HF, DELIVER, DETERMINE-A, DETERMINE-B, EMPEROR-Preserved, EMPEROR-Reduced and SOLOIST-WHF. He is also involved in the DAPA ACT HF-TIMI 68, FINEARTS-HF, STEP HFpEF, VESALIUS-CV, DARE-19, SELECT and CLEAR SYNERGY trials. He founded and oversees the CardioLink platform at St Michael's Hospital that is conducting cardiometabolic and surgically oriented RCTs and translational studies. Dr Verma leads a dynamic pre-clinical and translational research team that leverages pre-clinical disease models and clinical trial-derived data to identify novel mediators of cardiovascular and cardiometabolic disease as well as answer timely and relevant healthcare questions. His research has yielded two United States patents and is supported by several national peer-reviewed grants. Bobby YanagawaBobby YanagawaBobby Yanagawa is a surgeon in the Division of Cardiac Surgery, St Michael's Hospital, Canada. He is an Assistant Professor and Program Director, Division of Cardiac Surgery at the University of Toronto, Canada. Dr Yanagawa obtained his BSc and PhD from the University of British Columbia, Canada, and his MD degree and Cardiac Surgery Residency from the University of Toronto. He has completed research fellowships at the University of Wales College of Medicine and at St Michael's Hospital, Toronto, Canada. He completed a clinical fellowship at Mount Sinai Hospital, New York, USA. His clinical and research interests are in surgical revascularization and valvular surgery. Dr Yanagawa has published over 100 peer reviewed papers, 50 reviews and 15 book chapters. He has published in Nature Communications, Nature Medicine, Circulation, Journal of Thoracic and Cardiovascular Surgery and Annals of Thoracic Surgery. He was the AATS 13th Annual C. Walton Lillehei Award winner in 2010.

A21 OVEREXPRESSION OF ASCL2 ALTERS DIFFERENTIATION IN ESOPHAGEAL ORGANOIDS

BackgroundThe first population of stem cells in the esophageal epithelium was recently identified with the marker Keratin 15 ( Krt15). However, little is known about the mechanisms underlying the expansion and the function of these stem cells. It was shown that the transcription factor ASCL2 is upregulated in Krt15+ cells compared to Krt15- cells. Interestingly, ASCL2 is a gene target of the Wnt/β-catenin pathway, which acts as a regulator of proliferation and maintenance of the stemness state. The ultimate goal of my research project is to determine the role of ASCL2 in the maintenance of esophageal stem cells and to identify its binding partners.AimsInvestigate the role of ASCL2 in esophageal epithelial biology.MethodsLentiviral infection approach was used to obtain mouse esophageal organoids overexpressing ASCL2. Organoid culture, immunostaining (such as IF and H&E), qPCR, WB and proliferation assay were used to characterize the effect of ASCL2 overexpression on morphology, differentiation, proliferation, self-renewal and gene expression.ResultsFirst, ASCL2 overexpression was confirmed by WB. Interestingly, the morphology of organoid overexpressing ASCL2 was severely altered: organoids were smaller and less differentiated. Defect in differentiation was investigated by qPCR and IF using relevant markers such as p63, Krt13, Wnt5a and NT5E. Indeed, we observed an increase in basal marker ( p63), a decrease in suprabasal markers ( Krt13, Wnt5a) and in a stem cell marker ( NT5E). We also investigated the role of ASCL2 in self-renewal and observed that organoid formation capacity was reduced in ASCL2-overexpressing organoids. Furthermore, proliferation was also reduced in WST-1 assays. We also observed lower expression of the gene Top2a, a recently identified marker of the proliferative basal cell population in the human esophagus. Finally, we observed significant changes in the expression of genes associated with quiescent stem cells (Clu, ZFP36L2 and Anxa1).ConclusionsASCL2 overexpression alters differentiation and proliferation in organoids. ASCL2 could play a role in orchestrating cell fate decision in the esophageal epithelium.Funding AgenciesNSERC, Canada Research Chair

A238 ALTERED GUT MICROBIOME COMPOSITION AND FUNCTION ARE ASSOCIATED WITH GUT BARRIER DYSFUNCTION IN HEALTHY RELATIVES OF CROHN’S DISEASE PATIENTS

BackgroundThe gut microbiome may play a role in gut barrier homeostasis including epithelial barrier function, but data are scarce and limited to animal studiesAimsTo assess if alterations in gut microbiome are associated with gut barrier functionMethodsWe utilized the Genetic Environmental Microbial (CCC GEM) cohort of healthy first-degree relatives (FDRs) of Crohn’s disease (CD) patients. Gut barrier function was assessed using the ratio of urinary fractional excretion of lactulose to mannitol (LMR). Stool bacterial DNA was extracted and sequenced for the V4 hypervariable region of the 16S rRNA gene using MiSeq and processed using QIIME2. Microbial functions were imputed using PICRUSt2. The cohort was divided into a North American discovery cohort (n=2,472) and non-North American external validation cohort (n=655). LMR>0.025 was defined as abnormal. LMR-microbiome associations were assessed using multivariable regression model and Random Forest (RF) classifier algorithm. q<0.05 was considered significant when multiple tests were performedResultsThe median age of the entire cohort was 17.0 years [IQR 12.0; 24.0], 52.6% were females and 25.4% had LMR>0.025. In the discovery cohort, subjects with LMR>0.025 had markedly reduced alpha diversity (Chao1 index, estimate= -0.0037, p=4.0e-04) and altered beta diversity (Bray-Curtis dissimilarity index, PERMANOVA: pseudo-F statistic = 2.99, p=1.0e-03). We identified eight bacterial genera and 52 microbial pathways associated with LMR>0.025 (q<0.05). Four genera (decreased Adlercreutzia [odds ratio(OR)=0.74, 95% confidence interval (CI) 0.6–0.91], Clostridia-UCG-014 [OR=0.71, 95%CI 0.59–0.86], and Clostridium-sensu-stricto-1 [OR=0.75, 95%CI 0.61–0.92] and increased Colidextribacter [OR=1.65, 95%CI 1.2–2.26]) and eight pathways (including decreased biosynthesis of glutamate [OR=0.4, 95%CI 0.21–0.74], tryptophan [OR=0.06, 95%CI 0.01–0.27] and threonine [OR=0.038, 95%CI 0.003–0.41]) were replicated. Bacterial community composition was associated with gut barrier homeostasis as defined by the RF analysis (p= 1.4e-6)ConclusionsGut microbiome community and pathways are associated with gut barrier function. These findings may identify potential microbial targets to modulate barrier functionSubmitted on behalf of the CCC-GEM ConsortiumFunding AgenciesCCC, CIHRCrohn’s and Colitis Canada Genetics Environment Microbial (CCC-GEM) III; The Leona M. and Harry B. Helmsley Charitable Trust; Kenneth Croitoru is the recipient of the Canada Research Chair in Inflammatory Bowel Diseases

A157 DEFINITIONS OF MEDITERRANEAN DIET INCONSISTENTLY ASSOCIATE WITH MARKERS OF GUT BARRIER FUNCTION OR SUBCLINICAL INFLAMMATION IN A POPULATION-BASED COHORT

BackgroundThe Mediterranean Diet (MD) is proposed to reduce the risk of Crohn’s disease (CD) onset in cohort studies, with inconsistent results. This inconsistency may be due to heterogeneity in defining MD scores. Additionally, relationships between MD compliance and intestinal permeability or sub-clinical inflammation are not defined.AimsWe examined correlations between different MD scores, and determined associations between MD compliance and intestinal permeability or subclinical inflammation in a cohort of first degree relatives of CD patients.MethodsWe used food frequency questionnaire data from 2,112 subjects of the Crohn’s Colitis Canada- Genes, Environment, Microbial (CCC-GEM) project. We obtained 12 MD definitions from the literature and calculated daily percent compliance, we further compared MD scores via pairwise correlations (Kendall’s Tau). We measured intestinal permeability via urinary fractional excretion ratio of lactulose to mannitol (LMR) (LMR≥0.03 defined abnormal), and subclinical inflammation via fecal calprotectin (FCP) measured with BÜHLMANN fCAL® ELISA (FCP≥250 defined abnormal). We fit multivariable regression models between MD compliance and abnormal LMR and FCP, respectively. Two-sided p<0.05 defined significance.ResultsThere was large variation in cross-correlations among MD scores, from nil (t=0.0, p=0.54) to highly significant (t=0.97, p<2.2e-16). Associations of MD compliance and abnormal LMR or FCP were in both directions of effect, largely non-significant. Of the 12 MD scores, none associated with abnormal LMR, while 4 associated with abnormal FCP-Odds Ratios =1.22, 1.23, 1.24, and 1.30; p=0.02, 0.02, 0.01, and 0.009, and 95% Confidence Intervals = [1.03,1.45], [1.04,1.45], [1.05,1.47], and [1.07,1.59] respectively. No diet remained significant after correcting for multiple testing.ConclusionsCurrently MD definitions vary widely. Despite discrepancies, we expected consistent directions of effect for MD compliance on LMR or FCP. The largely non-significant associations between MDs suggest limitations in definition, interpretation, and relation to biological outcomes.Submitted on behalf of the CCC-GEM consortium.Funding AgenciesCIHRCrohn’s and Colitis Canada Genetics Environment Microbial (CCC-GEM) III;The Leona M. and Harry B. Helmsley Charitable Trust; Justine Timpano is a recipient of a fellowship award from Mount Sinai Hospital; Kenneth Croitoru is the recipient of the Canada Research Chair in Inflammatory Bowel Diseases

A236 ASSOCIATION OF STOOL METABOLOMIC PROFILE AND MICROBIOME COMPOSITION RISK SCORE WITH FUTURE ONSET OF CROHN’S DISEASE

BackgroundMicrobial composition-based risk score (MRS) was recently developed and validated to predict future risk of developing Crohn’s disease (CD) among healthy first-degree relatives (FDR) of CD patients. We hypothesized that stool metabolomic profiles, some of which are linked to the gut microbiome, are associated with future risk of CD.AimsTo assess the association of stool metabolomic profile with onset of CD and to determine the correlation between stool metabolites and the MRSMethodsHealthy FDR of CD patients were recruited as part of the nested case-control cohort of the CCC-GEM Project. Healthy FDRs who later developed CD (n=56) were matched approximately 1:1 by age, sex, follow-up duration, and geographical location with control FDRs remaining healthy (n=66). Stool metabolomics were assessed using the Metabolon’s DiscoveryHD4™ platform, and the stool microbiome characterised by 16s rDNA amplicon sequencing. We fitted a multivariable conditional logistic regression model on the disease status as a function of individual stool metabolites. We additionally performed Spearman correlation between each stool metabolite and the MRS.ResultsAmong 1,029 stool metabolites that were analyzed, 79 were associated with future risk of CD (p<0.05); however, none remained significant after multiple testing correction (FDR correction). Considering the exploratory nature of this study with limited sample size, we focused on the top seven metabolites associated with CD onset (p<0.01). Of these, two stool metabolites (dimethylglycine, methylmyristate) were associated with increased risk of CD onset while five (cytosine, guanine, cytidine, hydroxyglutarate, nervonate) were associated with decreased risk of developing CD. The two metabolites positively associated with CD onset were positively correlated with the MRS, while the five metabolites negatively associated with CD onset, were negatively correlated with the MRS. Meanwhile, 24 stool metabolites had significant correlation with MRS (FDR-corrected p<0.2). Among those, a total of four stool metabolites (cytosine, guanine, methymyristate, cytidine) overlapped with the top seven stool metabolites associated with CD onset.ConclusionsStool metabolite profiles may predict future risk of CD. A subset of these metabolites have significant correlation with the MRS with consistent direction of effect. This may suggest that stool metabolites mediate the putative effect of the gut microbiome on CD risk. Further validation in the full GEM cohort is warranted.Funding AgenciesCCC, CIHRThe Leona M. and Harry B. Helmsley Charitable Trust; Kenneth Croitoru is the recipient of the Canada Research Chair in Inflammatory Bowel Diseases; Sun-Ho Lee is a recipient of the Imagine/ CIHR/CAG Fellowship Award; Sun-Ho Lee, Juan Antonio Raygoza Garay, and Williams Turpin are recipients of fellowship awards from the Department of Medicine, Mount Sinai Hospital, Toronto, Canada.

Canadian Sovereignty in the Arctic

On November 22, 2021, Dr. Whitney Lackenbauer, Professor and Canada Research Chair at Trent University, presented Canadian-American Solutions to the Questions of Arctic Security at the 2021 CASIS West Coast Security Conference. The presentation was followed by a question and answer period with questions from the audience and CASIS Vancouver executives. The key points discussed were Canada’s sovereignty in the Arctic, the changing global threat environment, and the U.S.-Canada Arctic partnership.

GWAS and ExWAS of blood mitochondrial DNA copy number identifies 71 loci and highlights a potential causal role in dementia.

Mitochondrial DNA copy number (mtDNA-CN) is an accessible blood-based measurement believed to capture underlying mitochondrial (MT) function. The specific biological processes underpinning its regulation, and whether those processes are causative for disease, is an area of active investigation. We developed a novel method for array-based mtDNA-CN estimation suitable for biobank-scale studies, called 'automatic mitochondrial copy (AutoMitoC).' We applied AutoMitoC to 395,781 UKBiobank study participants and performed genome- and exome-wide association studies, identifying novel common and rare genetic determinants. Finally, we performed two-sample Mendelian randomization to assess whether genetically low mtDNA-CN influenced select MT phenotypes. Overall, genetic analyses identified 71 loci for mtDNA-CN, which implicated several genes involved in rare mtDNA depletion disorders, deoxynucleoside triphosphate (dNTP) metabolism, and the MT central dogma. Rare variant analysis identified SAMHD1 mutation carriers as having higher mtDNA-CN (beta = 0.23 SDs; 95% CI, 0.18-0.29; p=2.6 × 10-19), a potential therapeutic target for patients with mtDNA depletion disorders, but at increased risk of breast cancer (OR = 1.91; 95% CI, 1.52-2.40; p=2.7 × 10-8). Finally, Mendelian randomization analyses suggest a causal effect of low mtDNA-CN on dementia risk (OR = 1.94 per 1 SD decrease in mtDNA-CN; 95% CI, 1.55-2.32; p=7.5 × 10-4). Altogether, our genetic findings indicate that mtDNA-CN is a complex biomarker reflecting specific MT processes related to mtDNA regulation, and that these processes are causally related to human diseases. No funds supported this specific investigation. Awards and positions supporting authors include: Canadian Institutes of Health Research (CIHR) Frederick Banting and Charles Best Canada Graduate Scholarships Doctoral Award (MC, PM); CIHR Post-Doctoral Fellowship Award (RM); Wellcome Trust Grant number: 099313/B/12/A; Crasnow Travel Scholarship; Bongani Mayosi UCT-PHRI Scholarship 2019/2020 (TM); Wellcome Trust Health Research Board Irish Clinical Academic Training (ICAT) Programme Grant Number: 203930/B/16/Z (CJ); European Research Council COSIP Grant Number: 640580 (MO); E.J. Moran Campbell Internal Career Research Award (MP); CISCO Professorship in Integrated Health Systems and Canada Research Chair in Genetic and Molecular Epidemiology (GP).