Medicine and Health Sciences Commons^™

A Multidimensional Metabolomics Workflow To Image Biodistribution And Evaluate Pharmacodynamics In Adult Zebrafish, Madelyn M Jackstadt, Casey A Chamberlain, Steven R Doonan, Leah P Shriver, Gary J Patti

2020-Current year OA Pubs

An integrated evaluation of the tissue distribution and pharmacodynamic properties of a therapeutic is essential for successful translation to the clinic. To date, however, cost-effective methods to measure these parameters at the systems level in model organisms are lacking. Here, we introduce a multidimensional workflow to evaluate drug activity that combines mass spectrometry-based imaging, absolute drug quantitation across different biological matrices, in vivo isotope tracing and global metabolome analysis in the adult zebrafish. As a proof of concept, we quantitatively determined the whole-body distribution of the anti-rheumatic agent hydroxychloroquine sulfate (HCQ) and measured the systemic metabolic impacts of drug treatment. …

Il-34 Deficiency Impairs Foxp3+ Treg Function In A Model Of Autoimmune Colitis And Decreases Immune Tolerance Homeostasis, Antoine Freuchet, Marco Colonna, Et Al

2020-Current year OA Pubs

BACKGROUND: Immune homeostasis requires fully functional Tregs with a stable phenotype to control autoimmunity. Although IL-34 is a cytokine first described as mainly involved in monocyte cell survival and differentiation, we recently described its expression by CD8

METHODS: We generated Il34

RESULTS: Here we report that the absence of expression of IL-34 in Il34

CONCLUSION: Altogether, our data emphasize on the crucial necessity of IL-34 for immune homeostasis and for CD4

HIGHLIGHTS: -Absence of expression of IL-34 in Il34

Peptide-Sirna Nanoparticles Targeting Nf-Κb P50 Mitigate Experimental Abdominal Aortic Aneurysm Progression And Rupture, Huimin Yan, Ying Hu, Antonina Akk, Samuel A Wickline, Hua Pan, Christine T N Pham

2020-Current year OA Pubs

Abdominal aortic aneurysm (AAA) is a progressive vascular condition associated with high risk of mortality if left untreated. AAA is an inflammatory process with excessive local production of extracellular matrix degrading enzymes, leading to dilatation and rupture of the abdominal aorta. We posit that targeting NF-κB, a signaling pathway that controls inflammation, will halt AAA progression and prevent rupture. In an elastase-induced AAA model we observed that NF-κB activation increased progressively post-elastase perfusion. Unexpectedly, we found that AAA progression was marked by predominant nuclear accumulation of the NF-κB p50 subunit at the exclusion of p65. Using the amphipathic peptide p5RHH …

Effect Of A Glp-1 Mimetic On The Insulin Response To Oral Sugar Testing In Horses, Darko Stefanovski, Mary A Robinson, Andrew Van Eps

Faculty, Staff and Student Publications

BACKGROUND: Insulin dysregulation (ID) is the most important risk factor for the development of laminitis in horses and therapies to control it are needed.

HYPOTHESIS/OBJECTIVES: To assess the effects of a single dose of the synthetic GLP-1 analog exenatide on postprandial insulin dynamics. We hypothesized that exenatide would improve insulin sensitivity and lower postprandial blood insulin concentrations.

STUDY DESIGN: Randomized, crossover, experimental study.

ANIMALS: Six horses (3 mares, 3 geldings; 2 with normal insulin regulation [NIR] and 4 with mild ID).

METHODS: Horses completed both study arms: subcutaneous administration of exenatide (or no treatment) 30 min before an oral sugar …

Orbitofrontal Cortex Contributes To The Comparison Of Values Underlying Economic Choices, Sébastien Ballesta, Weikang Shi, Camillo Padoa-Schioppa

2020-Current year OA Pubs

Economic choices between goods entail the computation and comparison of subjective values. Previous studies examined neuronal activity in the orbitofrontal cortex (OFC) of monkeys choosing between different types of juices. Three groups of neurons were identified: offer value cells encoding the value of individual offers, chosen juice cells encoding the identity of the chosen juice, and chosen value cells encoding the value of the chosen offer. The encoded variables capture both the input (offer value) and the output (chosen juice, chosen value) of the decision process, suggesting that values are compared within OFC. Recent work demonstrates that choices are causally …

The Lupus Susceptibility Allele Drb1*03:01 Encodes A Disease-Driving Epitope, Bruna Miglioranza Scavuzzi, Vincent Van Drongelen, Bhavneet Kaur, Jennifer Callahan Fox, Jianhua Liu, Raquel A Mesquita-Ferrari, J Michelle Kahlenberg, Evan A Farkash, Fernando Benavides, Frederick W Miller, Amr H Sawalha, Joseph Holoshitz

Faculty, Staff and Student Publications

The HLA-DRB1*03:01 allele is a major genetic risk factor in systemic lupus erythematosus (SLE), but the mechanistic basis of the association is unclear. Here we show that in the presence of interferon gamma (IFN-γ), a short DRB1*03:01-encoded allelic epitope activates a characteristic lupus transcriptome in mouse and human macrophages. It also triggers a cascade of SLE-associated cellular aberrations, including endoplasmic reticulum stress, unfolded protein response, mitochondrial dysfunction, necroptotic cell death, and production of pro-inflammatory cytokines. Parenteral administration of IFN-γ to naïve DRB1*03:01 transgenic mice causes increased serum levels of anti-double stranded DNA antibodies, glomerular immune complex deposition and histopathological renal …

Maternal Iron Deficiency Programs Rat Offspring Hypertension In Relation To Renin-Angiotensin System And Oxidative Stress, Ya-Hui Chang, Wan-Hsuan Chen, Chung-Hao Su, Hong-Ren Yu, You-Lin Tain, Li-Tung Huang, Jiunn-Ming Sheen

Faculty, Staff and Student Publications

Hypertension is an important public health challenge, affecting up to 30-50% of adults worldwide. Several epidemiological studies indicate that high blood pressure originates in fetal life-the so-called programming effect or developmental origin of hypertension. Iron-deficiency anemia has become one of the most prevalent nutritional problems globally. Previous animal experiments have shown that prenatal iron-deficiency anemia adversely affects offspring hypertension. However, the underlying mechanism remains unclear. We used a maternal low-iron diet Sprague Dawley rat model to study changes in blood pressure, the renal renin-angiotensin system, oxidative stress, inflammation, and sodium transporters in adult male offspring. Our study revealed that 16-week-old …

Targeting De Novo Lipogenesis And The Lands Cycle Induces Ferroptosis In Kras-Mutant Lung Cancer, Caterina Bartolacci, Cristina Andreani, Gonçalo Vale, Stefano Berto, Margherita Melegari, Anna Colleen Crouch, Dodge L Baluya, George Kemble, Kurt Hodges, Jacqueline Starrett, Katerina Politi, Sandra L Starnes, Daniele Lorenzini, Maria Gabriela Raso, Luisa M Solis Soto, Carmen Behrens, Humam Kadara, Boning Gao, Ignacio I Wistuba, John D Minna, Jeffrey G Mcdonald, Pier Paolo Scaglioni

Faculty, Staff and Student Publications

Mutant KRAS (KM), the most common oncogene in lung cancer (LC), regulates fatty acid (FA) metabolism. However, the role of FA in LC tumorigenesis is still not sufficiently characterized. Here, we show that KMLC has a specific lipid profile, with high triacylglycerides and phosphatidylcholines (PC). We demonstrate that FASN, the rate-limiting enzyme in FA synthesis, while being dispensable in EGFR-mutant or wild-type KRAS LC, is required for the viability of KMLC cells. Integrating lipidomic, transcriptomic and functional analyses, we demonstrate that FASN provides saturated and monounsaturated FA to the Lands cycle, the process remodeling oxidized phospholipids, such as PC. Accordingly, …

Slc12a8 In The Lateral Hypothalamus Maintains Energy Metabolism And Skeletal Muscle Functions During Aging, Naoki Ito, Ai Takatsu, Hiromi Ito, Yuka Koike, Kiyoshi Yoshioka, Yasutomi Kamei, Shin-Ichiro Imai

2020-Current year OA Pubs

Sarcopenia and frailty are urgent socio-economic problems worldwide. Here we demonstrate a functional connection between the lateral hypothalamus (LH) and skeletal muscle through Slc12a8, a recently identified nicotinamide mononucleotide transporter, and its relationship to sarcopenia and frailty. Slc12a8-expressing cells are mainly localized in the LH. LH-specific knockdown of Slc12a8 in young mice decreases activity-dependent energy and carbohydrate expenditure and skeletal muscle functions, including muscle mass, muscle force, intramuscular glycolysis, and protein synthesis. LH-specific Slc12a8 knockdown also decreases sympathetic nerve signals at neuromuscular junctions and β2-adrenergic receptors in skeletal muscle, indicating the importance of the LH-sympathetic nerve-β2-adrenergic receptor axis. LH-specific overexpression …

Altered Genome-Wide Hippocampal Gene Expression Profiles Following Early Life Lead Exposure And Their Potential For Reversal By Environmental Enrichment, Garima Singh, V Singh, T Kim, A Ertel, W Fu, J S Schneider

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Early life lead (Pb) exposure is detrimental to neurobehavioral development. The quality of the environment can modify negative influences from Pb exposure, impacting the developmental trajectory following Pb exposure. Little is known about the molecular underpinnings in the brain of the interaction between Pb and the quality of the environment. We examined relationships between early life Pb exposure and living in an enriched versus a non-enriched postnatal environment on genome-wide transcription profiles in hippocampus CA1. RNA-seq identified differences in the transcriptome of enriched vs. non-enriched Pb-exposed animals. Most of the gene expression changes associated with Pb exposure were reversed by …

Regulated Dicing Of Pre-Mir-144 Via Reshaping Of Its Terminal Loop., Renfu Shang, Dmitry A Kretov, Scott I Adamson, Thomas Treiber, Nora Treiber, Jeffrey Vedanayagam, Jeffrey H Chuang, Gunter Meister, Daniel Cifuentes, Eric C Lai

Faculty Research 2022

Although the route to generate microRNAs (miRNAs) is often depicted as a linear series of sequential and constitutive cleavages, we now appreciate multiple alternative pathways as well as diverse strategies to modulate their processing and function. Here, we identify an unusually profound regulatory role of conserved loop sequences in vertebrate pre-mir-144, which are essential for its cleavage by the Dicer RNase III enzyme in human and zebrafish models. Our data indicate that pre-mir-144 dicing is positively regulated via its terminal loop, and involves the ILF3 complex (NF90 and its partner NF45/ILF2). We provide further evidence that this regulatory switch involves …

Sirpα Mediates Igf1 Receptor In Cardiomyopathy-Induced By Chronic Kidney Disease, Sandhya S Thomas, Jiao Wu, Giovanni Davogustto, Michael W Holliday, Kristin Eckel-Mahan, Daniela Verzola, Giacomo Garibotto, Zhaoyong Hu, William E Mitch, Heinrich Taegtmeyer

Faculty, Staff and Student Publications

BACKGROUND: Chronic kidney disease (CKD) is characterized by increased myocardial mass despite near-normal blood pressure, suggesting the presence of a separate trigger. A potential driver is SIRPα (signal regulatory protein alpha)-a mediator impairing insulin signaling. The objective of this study is to assess the role of circulating SIRPα in CKD-induced adverse cardiac remodeling.

METHODS: SIRPα expression was evaluated in mouse models and patients with CKD. Specifically, mutant, muscle-specific, or cardiac muscle-specific SIRPα KO (knockout) mice were examined after subtotal nephrectomy. Cardiac function was assessed by echocardiography. Metabolic responses were confirmed in cultured muscle cells or cardiomyocytes.

RESULTS: We demonstrate that …

Myt1l In The Making: Emerging Insights On Functions Of A Neurodevelopmental Disorder Gene, Jiayang Chen, Allen Yen, Colin P Florian, Joseph D Dougherty

2020-Current year OA Pubs

Large scale human genetic studies have shown that loss of function (LoF) mutations in MYT1L are implicated in neurodevelopmental disorders (NDDs). Here, we provide an overview of the growing number of published MYT1L patient cases, and summarize prior studies in cells, zebrafish, and mice, both to understand MYT1L's molecular and cellular role during brain development and consider how its dysfunction can lead to NDDs. We integrate the conclusions from these studies and highlight conflicting findings to reassess the current model of the role of MYT1L as a transcriptional activator and/or repressor based on the biological context. Finally, we highlight additional …

Advanced-Stage Melanoma At Presentation Following The Peak Of The Pandemic: A Covid-19 Cancer Canary In A Coal Mine, Ryan Lamm, Md, Walker Lyons, Md, Winnie So, Rn, Alliric I. Willis, Md, Facs, Msph

Department of Surgery Faculty Papers

Background: For melanoma patients, timely identification and tumor thickness are directly correlated with outcomes. COVID-19 impacted both patients' ability and desire to see physicians. We sought to identify whether the pandemic correlated with changes in melanoma thickness at presentation and subsequent treatment timeline.

Methods: Retrospective chart review was performed on patients who underwent surgery for melanoma in an academic center surgical oncology practice from May 2019 to September 2021. Patients were split into two cohorts: "pre-pandemic" from May 2019 to May 2020 and "pandemic," after May 2020, representing when these patients received their initial diagnostic biopsy. Demographic and melanoma-specific variables …

A Phospholipid Mimetic Targeting Lrh-1 Ameliorates Colitis, Suzanne G Mays, Emma H D'Agostino, Autumn R Flynn, Xiangsheng Huang, Guohui Wang, Xu Liu, Elizabeth J Millings, C Denise Okafor, Anamika Patel, Michael L Cato, Jeffery L Cornelison, Diana Melchers, René Houtman, David D Moore, John W Calvert, Nathan T Jui, Eric A Ortlund

Faculty, Staff and Students Publications

Phospholipids are ligands for nuclear hormone receptors (NRs) that regulate transcriptional programs relevant to normal physiology and disease. Here, we demonstrate that mimicking phospholipid-NR interactions is a robust strategy to improve agonists of liver receptor homolog-1 (LRH-1), a therapeutic target for colitis. Conventional LRH-1 modulators only partially occupy the binding pocket, leaving vacant a region important for phospholipid binding and allostery. Therefore, we constructed a set of molecules with elements of natural phospholipids appended to a synthetic LRH-1 agonist. We show that the phospholipid-mimicking groups interact with the targeted residues in crystal structures and improve binding affinity, LRH-1 transcriptional activity, …

Paclitaxel And Urolithin A Prevent Histamine-Induced Neurovascular Breakdown Alike, In An, Srijayaprakash Uppada, Dianxiong Zou, Erin M Scott, Gladys Ko, Stephen Pflugfelder, M N V Ravi Kumar, Raghu Ganugula

Faculty, Staff and Students Publications

Neurovascular eye problems are better prevented than managed or treated. Despite growing concern of occurrence in aging populations and development secondary to diseases such as diabetes and hypertension, we currently have very few options to tackle this global problem. Creating effective and high-throughput screening strategies is as important as the intervention itself. Here, we present for the first time a robust ex vivo rat eye model of histamine-induced vascular damage for investigating the therapeutic potential of paclitaxel (PTX) and urolithin A (UA) as alternatives to dexamethasone for preventing vascular damage in the retina. Extensive loss of vascularization and apoptosis were …

Acrylamide Inhibits Long-Term Potentiation And Learning Involving Microglia And Pro-Inflammatory Signaling, Yukitoshi Izumi, Chika Fujii, Kazuko A O'Dell, Charles F Zorumski

2020-Current year OA Pubs

Acrylamide is a chemical used in various industries and a product following high-temperature cooking of vegetables containing asparagine. Environmental or dietary exposure to acrylamide could impair cognitive function because of its neurotoxicity. Using rat hippocampal slices, we tested whether acrylamide alters induction of long-term potentiation (LTP), a cellular model of learning and memory. We hypothesized that acrylamide impairs cognitive function via activation of pro-inflammatory cytokines because robust upregulation of NLRP3 inflammasome has been reported. Although acrylamide up to 3 mM did not alter basal synaptic transmission, incubation with 10 μM or acute administration of 100 μM acrylamide inhibited induction of …

Kathryn V. Holmes: A Career Of Contributions To The Coronavirus Field, Aurelio Bonavia, Samuel R Dominguez, Gabriela Dveksler, Sara Gagneten, Megan Howard, Scott Jeffers, Zhaohui Qian, Mary Kathryn Smith, Larissa B Thackray, Dina B Tresnan, David E Wentworth, David R Wessner, Richard K Williams, Tanya A Miura

2020-Current year OA Pubs

Over the past two years, scientific research has moved at an unprecedented rate in response to the COVID-19 pandemic. The rapid development of effective vaccines and therapeutics would not have been possible without extensive background knowledge on coronaviruses developed over decades by researchers, including Kathryn (Kay) Holmes. Kay's research team discovered the first coronavirus receptors for mouse hepatitis virus and human coronavirus 229E and contributed a wealth of information on coronaviral spike glycoproteins and receptor interactions that are critical determinants of host and tissue specificity. She collaborated with several research laboratories to contribute knowledge in additional areas, including coronaviral pathogenesis, …

The Hippo Pathway Regulates Axis Formation And Morphogenesis In Hydra, Maria Brooun, Willi Salvenmoser, Catherine Dana, Marius Sudol, Robert Steele, Bert Hobmayer, Helen Mcneill

2020-Current year OA Pubs

How did cells of early metazoan organisms first organize themselves to form a body axis? The canonical Wnt pathway has been shown to be sufficient for induction of axis in Cnidaria, a sister group to Bilateria, and is important in bilaterian axis formation. Here, we provide experimental evidence that in cnidarian

Sox9 Directs Divergent Epigenomic States In Brain Tumor Subtypes, Debosmita Sardar, Hsiao-Chi Chen, Amanda Reyes, Srinidhi Varadharajan, Antrix Jain, Carrie Mohila, Rachel Curry, Brittney Lozzi, Kavitha Rajendran, Alexis Cervantes, Kwanha Yu, Ali Jalali, Ganesh Rao, Stephen C Mack, Benjamin Deneen

Duncan NRI Faculty and Staff Publications

Epigenetic dysregulation is a universal feature of cancer that results in altered patterns of gene expression that drive malignancy. Brain tumors exhibit subtype-specific epigenetic alterations; however, the molecular mechanisms responsible for these diverse epigenetic states remain unclear. Here, we show that the developmental transcription factor Sox9 differentially regulates epigenomic states in high-grade glioma (HGG) and ependymoma (EPN). Using our autochthonous mouse models, we found that Sox9 suppresses HGG growth and expands associated H3K27ac states, while promoting ZFTA-RELA (ZR

Hippo-Taz Signaling Is The Master Regulator Of The Onset Of Triple-Negative Basal-Like Breast Cancers, Hirotoshi Soyama, Miki Nishio, Junji Otani, Toshiko Sakuma, Shintaro Takao, Shigeo Hara, Takaaki Masuda, Koshi Mimori, Shinya Toyokuni, John P Lydon, Kazuwa Nakao, Hiroshi Nishina, Takumi Fukumoto, Tomohiko Maehama, Akira Suzuki

Faculty, Staff and Students Publications

A universal oncogenic driver of basal-like breast cancer (BLBC) has resisted identification. We show that continuous transcriptional coactivator with PDZ-binding motif (TAZ) activation in precancerous murine luminal cells generates luminal cancers that later become BLBCs. Subsequent TP53 alteration, a feature of invasive human BLBCs, accelerates tumor progression. Because BLBC development is inhibited by TAZ inactivation in vivo, our work provides a sound rationale for targeting Hippo-TAZ signaling as therapy for human BLBC. Our mouse model of BLBC represents a powerful tool for evaluating such drugs.

Cranial Base Synchondrosis Lacks Pthrp-Expressing Column-Forming Chondrocytes, Shawn A Hallett, Annabelle Zhou, Curtis Herzog, Ariel Arbiv, Wanida Ono, Noriaki Ono

Faculty, Staff and Student Publications

The cranial base contains a special type of growth plate termed the synchondrosis, which functions as the growth center of the skull. The synchondrosis is composed of bidirectional opposite-facing layers of resting, proliferating, and hypertrophic chondrocytes, and lacks the secondary ossification center. In long bones, the resting zone of the epiphyseal growth plate houses a population of parathyroid hormone-related protein (PTHrP)-expressing chondrocytes that contribute to the formation of columnar chondrocytes. Whether PTHrP+ chondrocytes in the synchondrosis possess similar functions remains undefined. Using Pthrp-mCherry knock-in mice, we found that PTHrP+ chondrocytes predominantly occupied the lateral wedge-shaped area of the synchondrosis, unlike …

Α-Synuclein Conformational Plasticity: Physiologic States, Pathologic Strains, And Biotechnological Applications, Amanda Li, Cyrus Rastegar, Xiaobo Mao

2020-Current year OA Pubs

α-Synuclein (αS) is remarkable for both its extensive conformational plasticity and pathologic prion-like properties. Physiologically, αS may populate disordered monomeric, helically folded tetrameric, or membrane-bound oligomeric states. Pathologically, αS may assemble into toxic oligomers and subsequently fibrils, the prion-like transmission of which is implicated in a class of neurodegenerative disorders collectively termed α-synucleinopathies. Notably, αS does not adopt a single "amyloid fold", but rather exists as structurally distinct amyloid-like conformations referred to as "strains". The inoculation of animal models with different strains induces distinct pathologies, and emerging evidence suggests that the propagation of disease-specific strains underlies the differential pathologies observed …

Impairing Proliferation Of Glioblastoma Multiforme With Cd44+ Selective Conjugated Polymer Nanoparticles, Dorota Lubanska, Sami Alrashed, Gage T Mason, Fatima Nadeem, Angela Awada, Mitchell Dipasquale, Alexandra Sorge, Aleena Malik, Monika Kojic, Mohamed A R Soliman, Ana C Decarvalho, Abdalla Shamisa, Swati Kulkarni, Drew Marquardt, Lisa A Porter, Simon Rondeau-Gagné

Faculty, Staff and Student Publications

Glioblastoma is one of the most aggressive types of cancer with success of therapy being hampered by the existence of treatment resistant populations of stem-like Tumour Initiating Cells (TICs) and poor blood-brain barrier drug penetration. Therapies capable of effectively targeting the TIC population are in high demand. Here, we synthesize spherical diketopyrrolopyrrole-based Conjugated Polymer Nanoparticles (CPNs) with an average diameter of 109 nm. CPNs were designed to include fluorescein-conjugated Hyaluronic Acid (HA), a ligand for the CD44 receptor present on one population of TICs. We demonstrate blood-brain barrier permeability of this system and concentration and cell cycle phase-dependent selective uptake …

Cd11bhigh B Cells Increase After Stroke And Regulate Microglia: Cd11bhigh B Cells Increase After Stroke And Regulate Mg, Janelle M Korf, Pedram Honarpisheh, Eric C Mohan, Anik Banerjee, Maria P Blasco-Conesa, Parisa Honarpisheh, Gary U Guzman, Romeesa Khan, Bhanu P Ganesh, Amy L Hazen, Juneyoung Lee, Aditya Kumar, Louise D Mccullough, Anjali Chauhan

Faculty, Staff and Student Publications

Recent studies have highlighted the deleterious contributions of B cells to post-stroke recovery and cognitive decline. Different B cell subsets have been proposed based on expression levels of transcription factors (e.g. T-bet) as well as specific surface proteins. CD11b (α-chain of integrin) is expressed by several immune cell types and is involved in regulation of cell motility, phagocytosis, and other essential functions of host immunity. Although B cells express CD11b, the CD11b^high subset of B cells has not been well characterized, especially in immune dysregulation seen with aging and after stroke. Here, we investigate the role of CD11b^{high …}

Infiltration Of Peripheral Immune Cells Into The Olfactory Bulb In A Mouse Model Of Acute Nasal Inflammation, Hinami Asano, Sanae Hasegawa-Ishii, Ken Arae, Aki Obara, Geoffroy Laumet, Robert Dantzer, Atsuyoshi Shimada

Faculty, Staff and Student Publications

Chronic nasal inflammation induces robust olfactory bulb (OB) atrophy in mice. Here we examined initial events that occur in the OB after bilateral intranasal administration of lipopolysaccharide, focusing on the olfactory nerve fibers and meninges. We analyzed the time course of OB and meninges inflammation using histological and biochemical approaches. Within 12 h, we observed increased chemokine expression and transient infiltration of peripheral immune cells into the OB, resulting in the development of pro-inflammatory status in the OB. Meningeal immunity was activated. Resident microglia produced anti-inflammatory cytokines within 24 h. These could be the initial events that lead to OB …

Slitrk2 Variants Associated With Neurodevelopmental Disorders Impair Excitatory Synaptic Function And Cognition In Mice, Salima El Chehadeh, Dorothy K Grange, Et Al

2020-Current year OA Pubs

SLITRK2 is a single-pass transmembrane protein expressed at postsynaptic neurons that regulates neurite outgrowth and excitatory synapse maintenance. In the present study, we report on rare variants (one nonsense and six missense variants) in SLITRK2 on the X chromosome identified by exome sequencing in individuals with neurodevelopmental disorders. Functional studies showed that some variants displayed impaired membrane transport and impaired excitatory synapse-promoting effects. Strikingly, these variations abolished the ability of SLITRK2 wild-type to reduce the levels of the receptor tyrosine kinase TrkB in neurons. Moreover, Slitrk2 conditional knockout mice exhibited impaired long-term memory and abnormal gait, recapitulating a subset of …

Cd11b Suppresses Tlr Activation Of Nonclassical Monocytes To Reduce Primary Graft Dysfunction After Lung Transplantation, Melissa Querrey, Stephen Chiu, Emilia Lecuona, Qiang Wu, Haiying Sun, Megan Anderson, Megan Kelly, Sowmya Ravi, Alexander V. Misharin, Daniel Kreisel, Ankit Bharat, G. R. Scott Budinger

2020-Current year OA Pubs

Primary graft dysfunction (PGD) is the leading cause of postoperative mortality in lung transplant recipients and the most important risk factor for development of chronic lung allograft dysfunction. The mechanistic basis for the variability in the incidence and severity of PGD between lung transplant recipients is not known. Using a murine orthotopic vascularized lung transplant model, we found that redundant activation of Toll-like receptors 2 and 4 (TLR2 and -4) on nonclassical monocytes activates MyD88, inducing the release of the neutrophil attractant chemokine CXCL2. Deletion of Itgam (encodes CD11b) in nonclassical monocytes enhanced their production of CXCL2 and worsened PGD, …

Neuronal Activity Induces Glucosylceramide That Is Secreted Via Exosomes For Lysosomal Degradation In Glia, Liping Wang, Guang Lin, Zhongyuan Zuo, Yarong Li, Seul Kee Byeon, Akhilesh Pandey, Hugo J Bellen

Duncan NRI Faculty and Staff Publications

Recessive variants in GBA1 cause Gaucher disease, a prevalent form of lysosome storage disease. GBA1 encodes a lysosomal enzyme that hydrolyzes glucosylceramide (GlcCer) into glucose and ceramide. Its loss causes lysosomal dysfunction and increased levels of GlcCer. We generated a null allele of the Drosophila ortholog Gba1b by inserting the Gal4 using CRISPR-Cas9. Here, we show that Gba1b is expressed in glia but not in neurons. Glial-specific knockdown recapitulates the defects found in Gba1b mutants, and these can be rescued by glial expression of human GBA1. We show that GlcCer is synthesized upon neuronal activity, and it is transported …

Gut Bacterial Isoamylamine Promotes Age-Related Cognitive Dysfunction By Promoting Microglial Cell Death, Yun Teng, Jingyao Mu, Fangyi Xu, Xiangcheng Zhang, Mukesh K Sriwastva, Qiaohong M Liu, Xiaohong Li, Chao Lei, Kumaran Sundaram, Xin Hu, Lifeng Zhang, Juw Won Park, Jae Yeon Hwang, Eric C Rouchka, Xiang Zhang, Jun Yan, Michael L Merchant, Huang-Ge Zhang

Faculty, Staff and Student Publications

The intestinal microbiome releases a plethora of small molecules. Here, we show that the Ruminococcaceae metabolite isoamylamine (IAA) is enriched in aged mice and elderly people, whereas Ruminococcaceae phages, belonging to the Myoviridae family, are reduced. Young mice orally administered IAA show cognitive decline, whereas Myoviridae phage administration reduces IAA levels. Mechanistically, IAA promotes apoptosis of microglial cells by recruiting the transcriptional regulator p53 to the S100A8 promoter region. Specifically, IAA recognizes and binds the S100A8 promoter region to facilitate the unwinding of its self-complementary hairpin structure, thereby subsequently enabling p53 to access the S100A8 promoter and enhance S100A8 expression. …