Medical Genetics Commons^™

Mtorc2-Nav1.2 Signaling Drives Early Hyperexcitability In Alzheimer’S Disease Mouse Model, Nolan M Dvorak, Jeffrey L Noebels

Faculty, Staff and Students Publications

Hyperexcitability is a biomarker of early-stage Alzheimer’s Disease (AD) and hastens cognitive decline later in its course. Mechanistic target of rapamycin (mTOR) signaling contributes to the slope of this trajectory, as evidenced by early increased brain expression and the rescue of hyperexcitability by genetic deletion of mTOR complex 2 (mTORC2); however, a molecular mechanism directly linking mTOR signaling to membrane hyperexcitability in early-stage AD remains elusive. Here, we show that hyperactive mTOR signaling stimulates the voltage-gated Na+ channel 1.2 (Nav1.2), a previously identified downstream phosphorylation target of mTORC2 and a key regulator of membrane electrogenesis. Augmented Nav1.2 channel function induced …

Selective Loss Of Primary Cilia And Neurotrophic Signaling In G51d Α-Synuclein Mice Highlights A Common Pathway To Parkinson’S Disease, Yu-En Lin, Ebsy Jaimon, Youngdoo Kim, Annabeth Loftman, Aaran Vijayakumaran, Benjamin D W Belfort, Claire Y Chiang, Benjamin R Arenkiel, Huda Y Zoghbi, Suzanne R Pfeffer

Duncan NRI Faculty and Staff Publications

Parkinson's disease is characterized by dopaminergic neuron loss and accumulation of α-synuclein aggregates in the brain. G51D α-synuclein knock-in mice provide a genetically and clinically relevant model of disease, exhibiting early olfactory deficits, age-dependent motor impairment, and progressive phospho-α-synuclein accumulation. In multiple Parkinson's disease models, striatal cholinergic and parvalbumin interneurons, as well as astrocytes, lose primary cilia and the neurotrophic signaling needed to sustain dopaminergic neurons. We show here that G51D α-synuclein mice share these phenotypes. Phospho-Ser129 α-synuclein accumulation correlates with cilia loss in cholinergic interneurons but not in spiny projection neurons that accumulate higher phospho-α-synuclein levels. In the piriform …

Translational Reading Frame Predicts The Pathogenicity Of C-Terminal Frameshift Deletions In Mecp2, Jacky Guy, Elena Hein, Beatrice Alexander-Howden, Timur Von Bock Und Polach, Tricia Mathieson, Benjamin P Kleinstiver, Huda Y Zoghbi, Adrian Bird

Duncan NRI Faculty and Staff Publications

Mutations in the MECP2 gene cause the severe neurological disorder Rett syndrome. A cluster of frameshift-causing C-terminal deletions (CTDs) removes ~100 amino acids and accounts for approximately 10% of RTT-causing mutations. Their pathogenicity is unexpected because this C-terminal domain is dispensable in mice. Analysis of pathogenic and benign human MECP2 variants reveals that some individuals with apparently typical CTDs do not develop Rett syndrome, confirming that C-terminal truncations are not intrinsically pathogenic. Using human sequence data and mouse models we show that pathogenicity results from a marked reduction in MeCP2 levels and depends on the presence of a proline proline …

Hippo Signaling Regulates Cuticle Pigmentation And Dopamine Metabolism In Drosophila, Shelley B Gibson, Samantha L Deal, Ye-Jin Park, Bo Sun, Yanyan Qi, Jung-Wan Mok, Hyung-Lok Chung, Hongjie Li, Shinya Yamamoto

Duncan NRI Faculty and Staff Publications

Pigmentation plays multiple important roles in development, physiology and evolution. Melanization of the insect cuticle requires dopamine as a precursor of melanin and involves key enzymes in dopamine biosynthesis including Tyrosine hydroxylase (TH) and Dopa decarboxylase (Ddc). Some studies have hinted that disruption of the evolutionarily conserved Hippo signaling pathway, which has been primarily studied in the context of tissue growth, may lead to changes in cuticle pigmentation in the fruit fly Drosophila melanogaster. However, to our knowledge, there have not been any systematic investigations into their potential mechanistic links. In this study, we identified that all genes that comprise …

Tau Pathology In Epilepsy: Emerging Mechanisms And Translational Opportunities, Arjune Sen, Xin You Tai, Aristea Galanopoulou, Maria Thom, Eleonora Aronica, Lucy Vivash, Martin Hardmeier, Action Amos, Stephan Rueegg, Matthias Koepp, Yaroslav Winter, Christoph Helmstaedter, Jeffrey L Noebels, Hilal A Lashuel, Terence J O'Brien

Faculty, Staff and Students Publications

The onset of epilepsy in adulthood occurs most commonly after 55 years of age. Given the ageing global population, this disorder represents an increasing burden on healthcare and society. The bidirectional link between epilepsy and dementia is a focus of intense research with underlying tau pathology highlighted as a potential mechanistic link. In this review, we examine the evidence for tau-related neurodegenerative processes in epilepsy beginning with how changes in biochemical and structural properties of the tau protein can lead to abnormal phosphorylation and pathological aggregation. We consider the role of tau in seizure occurrence and cognitive difficulties in experimental …

Hp1bp3 Loss Links Chromatin Reorganization To Metabolic Vulnerability In Glioma, Brittney Lozzi, Taylor A Gatesman, Pushan Dasgupta, Debosmita Sardar, Yeunjung Ko, Chenyu Mao, Hsiao-Chi Chen, Rachel N Curry, Dongjoo Choi, Carrie A Mohila, Melissa L Bondy, Ganesh Rao, Marco Gallo, Sameer Agnihotri, Benjamin Deneen

Duncan NRI Faculty and Staff Publications

High-grade gliomas (HGGs) are aggressive brain tumors with poor prognosis, driven in part by metabolic and epigenetic adaptations. Methionine metabolism supports HGG growth by supplying S-adenosylmethionine for methylation reactions, yet how nutrient availability influences chromatin organization in HGG remains incompletely understood. Using an immunocompetent mouse model of HGG, we found that dietary methionine restriction reduced tumor proliferation, extended survival, and induced partial nuclear inversion. We identified Hp1bp3 as a key regulator of tumor growth that functions by interacting with nuclear tethering proteins to mediate chromatin reorganization. Loss of Hp1bp3 results in the upregulation of histone demethylases leading to selective depletion …

In Vivo Orf Overexpression Screening Identifies Ccn4 As A Regulator Of Glioblastoma Growth Validated Across Multiple Models, Pushan Dasgupta

Faculty, Staff and Students Publications

Despite current multimodal therapies for glioblastoma (GBM), its prognosis remains grim. Thus, a tremendous need exists to identify new genetic drivers that may serve as potential therapeutic targets in glioblastoma (GBM). We describe an in vivo overexpression screening strategy to identify drivers of glioblastoma where we have leveraged TCGA datasets to conduct a functional genomics screen of prioritized open reading frames (ORFs) that are overexpressed and/or amplified in GBM. To interrogate these potential drivers within a more relevant physiological context, the screening was accomplished in vivo in an orthotopic patient-derived glioma stem-like cell (GSC) model. Among 5 positive "hits" from …

Cytosine Base Editing Of Lpa In Transgenic Mice Averts Large Deletions, Marcel A Chuecos, So Hyun Park, Madhvi M Bhakta, Usosa Too-Chiobi, Daniel Betancourth, Mingming Cao, Marco De Giorgi, Christopher J Walkey, Anjana Tiwari, Biana Godin, Julia M Assini, Donna J Palmer, Philip Ng, Michael B Boffa, Marlys L Koschinsky, Gang Bao, William R Lagor

Faculty, Staff and Students Publications

Lipoprotein(a) (Lp(a)) is a genetically determined causal risk factor for cardiovascular disease, with approximately 20% of the population exhibiting elevated levels. While there are promising drugs in development, there are currently no approved therapies specifically designed to lower Lp(a) levels. For high-risk individuals with extreme levels of Lp(a), liver-directed genome editing could be an effective one-time solution. Genome editing approaches such as CRISPR and TALENs can reduce Lp(a) in LPA-transgenic mouse models, but they frequently induce large and potentially harmful genomic deletions. Here, we report the first application of TadA-derived cytosine base editing (CBE), delivered via helper-dependent adenovirus (HDAdV) and …

Structural Determinants Of Ligand Response Specificity In The Mast Cell Activating Gpcr, Mrgprx2, Abiodun Adefola R Adeosun, Melina A Agosto, Olivier Lichtarge, Theodore G Wensel

Faculty, Staff and Students Publications

The mast cell-specific G-protein-coupled receptor (GPCR) MRGPRX2 (Mas-Related G Protein-coupled Receptor X2) has roles in itch and pain, and it mediates clinically relevant allergy-like responses to a diverse assortment of drugs. The varied responses of individuals to MRGPRX2 agonists, leading to drug hypersensitivity reactions in some cases, suggests the presence of consequential variants in the population. However, genetic associations with drug responses are poorly understood. We used heterologously-expressed MRGPRX2 to investigate the effect of 18 naturally occurring non-synonymous single nucleotide polymorphisms on activation by representative compounds from several classes, including neuropeptides, opioid agonists, antibiotics, neuromuscular blocking agents, and polycationic aromatic …

Systems Genetic Dissection Of Brain Gene Expression Reveals Excitotoxic Mechanisms Of Alzheimer’S Disease, Pinghan Zhao, Omar El Fadel, Anh Le, Carl Grant Mangleburg, Justin Dhindsa, Timothy Wu, Jinghan Zhao, Meichen Huang, Bismark Amoh, Aditi Sai Marella, Yarong Li, Nicholas T Seyfried, Allan I Levey, Zhandong Liu, Ismael Al-Ramahi, Juan Botas, Joshua M Shulman

Faculty, Staff and Students Publications

Gene expression changes likely mediate the impact of Alzheimer's disease (AD) neuropathology on cognition, but there are challenges to resolve the proximal causal pathways from postmortem brain transcriptome profiles which lack temporal resolution and are further confounded by mixed pathologies. Here, we functionally dissect 30 AD-associated human brain gene co-expression modules using fruit fly (Drosophila melanogaster) models. Integrating longitudinal RNA-sequencing and behavioral phenotyping, we interrogated the consequences of amyloid beta (Aβ) plaques, tau neurofibrillary tangles, and aging, highlighting hundreds of conserved, differentially expressed genes. To pinpoint causal modules and drivers, we manipulated 344 prioritized targets in vivo, identifying 141 modifiers …

Genetic Analysis Of The X-Linked Adrenoleukodystrophy Gene Abcd1 In Drosophila Uncovers A Conserved Phenotype, Joshua Manor, Sharayu V Jangam, Hyung-Lok Chung, Pranjali Bhagwat, Jonathan C Andrews, Hillary Chester, Shu Kondo, Saurabh Srivastav, Juan Botas, Ann B Moser, Suzette M Huguenin, Michael F Wangler

Duncan NRI Faculty and Staff Publications

X-linked adrenoleukodystrophy (X-ALD) is a progressive neurodegenerative disorder caused by a loss-of-function (LOF) mutation in the ATP-binding cassette subfamily D member 1 (ABCD1) gene, leading to the accumulation of very long-chain fatty acids (VLCFAs). This disorder exhibits striking heterogeneity; some male patients develop an early childhood neuroinflammatory demyelination disorder, while other patients, including adult males and most affected female carriers, experience a chronic progressive myelopathy. Adrenocortical failure is observed in almost all male patients, with the age of onset varying, sometimes being the first diagnostic finding. The gene underlying this spectrum of disease encodes an ATP-binding cassette (ABC) transporter that …

Yap Induces A Prorenewal Metabolic State In Cardiomyocytes, Lin Liu, Jeffrey D Steimle, Chang-Ru Tsai, Fansen Meng, Yuka Morikawa, Yi Zhao, Sandra Carmichael, Xiao Li, James F Martin

Faculty, Staff and Students Publications

BACKGROUND: Cardiomyocytes, as highly specialized and differentiated somatic cells, possess a limited capacity for renewal. Neonatal rodents possess the ability to regenerate cardiomyocytes after injury; however, this regenerative capacity declines rapidly with cardiomyocyte maturation, suggesting an inhibitory network between cellular maturation and cardiomyocyte proliferation. Maturing cardiomyocytes undergo a metabolic shift from predominantly glycolysis in the neonatal state to increased fatty acid oxidation in the mature state, which poses a barrier to cardiomyocyte proliferation and cardiac regenerative repair. YAP, a transcriptional cofactor regulated by the Hippo signaling pathway, promotes cardiac regenerative repair. We investigated the role of YAP in mediating metabolic …

A Multidomain Peptide Hydrogel-Liposome Composite For Controlled Release Of A Cyclic Dinucleotide In Oral Cancer, Joseph W R Swain, Andrea H Molina, Gemalene M Sunga, Danielle Chew-Martinez, Neeraja Dharmaraj, Alejandra Cobos Perez, Arghadip Dey, Ephraim J Vázquez-Rosado, Simon Young, Jeffrey D Hartgerink

Faculty, Staff and Student Publications

While immunotherapy is a promising treatment strategy for cancer, the majority of head and neck squamous cell carcinoma (HNSCC) patients treated with single-agent immunotherapy do not respond. Therefore, researchers are investigating combination treatments with immunostimulatory molecules that can maximize anti-tumor responses. Cyclic dinucleotides (CDNs) are STING agonists that hold promise in combination approaches, but they require frequent intratumoral administration when used in both preclinical models of HNSCC and clinical trials. To reduce administration frequency, we have created a peptide hydrogel–liposome composite system, K2-Lip(CDN), for local and prolonged availability of CDN. We investigated the loading limits of cationic liposomes in both …

Multiparametric Mri To Predict Response To Irreversible Electroporation Plus Anti-Pd-1 Immunotherapy In Pancreatic Ductal Adenocarcinoma, Qizhen Cao, Mark D Pagel, Charles V Kingsley, Jingfei Ma, James P Long, Xiaoxia Wen, Seth T Gammon, Jorge Delacerda, Sanaz Javadi, Chun Li

Faculty, Staff and Student Publications

Purpose: To investigate contrast-enhanced T1-weighted MRI and diffusion-weighted magnetic resonance imaging (DWI) for early prediction of tumor response to combined irreversible electroporation (IRE) and anti-PD-1 immunotherapy.

Methods: Murine pancreatic ductal adenocarcinoma (PDAC) cells KRAS* were inoculated into the pancreas of C57BL/6 mice. IRE was performed when tumors became palpable. After IRE, mice received six intraperitoneal injections of anti-PD-1 over 2 weeks. T2-weighted MRI, T1-weighted MRI with macromolecular contrast agent poly(L-glutamic acid)-conjugated gadolinium (PG-Gd), and DWI were performed before and after IRE. Survival was analyzed using Kaplan-Meier curves. Mice surviving at least 100 days without recurrence after IRE were considered complete …

Gompertz Growth With A Shared Carrying Capacity Optimally Simulates Primary And Metastatic Tumor Growth Dynamics, Pirmin Schlicke, Preethi Korangath, Xiaoxi Pan, Caner Ercan, Kathleen Gabrielson, Lyndsey Werhane, Yinyin Yuan, Sébastien Benzekry, Robert Ivkov, Heiko Enderling

Faculty, Staff and Student Publications

Background: Cancer is a systemic disease with most deaths attributed to metastatic burden. Primary and metastatic tumors, albeit at different anatomic locations, are interconnected through multiple biological processes. Pre-clinical and clinical observations of growth acceleration of metastases after surgery, or abscopal effects outside the radiation field are widely reported, yet reliably triggering favorable and avoiding unfavorable systemic responses remains an unmet clinical need. Understanding local and systemic tumor interaction dynamics will help guide future treatments.

Methods: We analyze the data of multiple in vivo tumor models. We formalize the systemic interplay of tumors as mathematical differential equation and calibrate parameters …

Structural-Functional Analyses Of The Huntingtin/Hap40 Complex In Drosophila And Humans, Stephen M Farmer, Amanda Solbach, Shiyu Xu, Beatriz Rios, Xin Ye, Amy Gao, Daniela Covarrubias, Yue Yu, Lili Ye, Vicky Chuong, Erin Furr Stimming, Haiqing Zhao, Sheng Zhang

Faculty, Staff and Student Publications

Huntington's disease (HD) is a neurodegenerative disorder caused by an abnormal CAG expansion in the Huntingtin (HTT) gene. Given its simple genetic cause but complex pathogenic mechanisms, interest in targeting HTT for HD treatment is growing, necessitating a clear understanding of HTT regulation. HTT protein primarily exists in a core complex with HAP40, forming a highly ordered structure with two large globular domains connected by a bridge. We previously demonstrated that HAP40 is conserved in

Neutrophil-Microglia Interaction Drives Motor Dysfunction In A Neuromyelitis Optica Model Induced By Subarachnoid Aqp4-Igg, Fangfang Qi, Vanda A Lennon, Shunyi Zhao, Yong Guo, Husheng Ding, Caiyun Liu, Whitney M Bartley, Tingjun Chen, Claudia F Lucchinetti, Long-Jun Wu

Faculty, Staff and Student Publications

Neutrophils and neutrophil extracellular traps (NETs) contribute to early neuromyelitis optica (NMO) histopathology initiated by IgG targeting astrocytic aquaporin-4 (AQP4) water channels. Yet, the mechanisms underlying neutrophil recruitment and their pathogenic roles in disease progression remain unclear. To investigate molecular-cellular events preceding classical complement cascade activation in a mouse NMO model, we continuously infused, via spinal subarachnoid route, a non-complement-activating mouse monoclonal AQP4-IgG. Parenchymal infiltration of netting neutrophils containing C5a ensued with microglial activation and motor impairment but no blood-brain barrier leakage. Motor impairment and neuronal dysfunction both reversed when AQP4-IgG infusion stopped. Two-photon microscopy and electron microscopy-based reconstructions revealed …

Self-Clustering Of Three Cbx2 Molecules Drives Prc2 To Promote Facultative Heterochromatinization Of Polycomb Target Genes, Steven Ingersoll, Abby Trouth, J Carlos Angel, Xinlong Luo, Axel Espinoza, Joey Wen, Chengjie Zhu, Joseph Tucker, Kalkidan Astatike, Christopher J Phiel, Hatim Sabaawy, Tatiana G Kutateladze, Tao P Wu, Tingting Yao, Chao Lu, Srinivas Ramachandran, Xiaojun Ren

Faculty, Staff and Students Publications

Phase separation is increasingly recognized in facultative heterochromatinization of Polycomb target genes; however, the mechanisms underlying this process remain obscure. Using single-molecule imaging and tracking, we show that individual condensates in mouse embryonic stem cells (mESCs) contain approximately 3 CBX2 molecules and numerous Polycomb repressive complex (PRC)1 and PRC2 subunits and indicate that the composition and dynamics of condensates are developmentally regulated. We reveal that CBX2 clusters PRC2 and controls the spatial distribution of both PRC2 and H3K27me3. Using genomic approaches, we demonstrate that CBX2 binds to condensate initiation sites, which are enriched for PRC2 nucleation sites. CBX2 deletion causes …

Pkmζ-Kibra Interactions, Molecular Turnover, And Memory, Changchi Hsieh, David A Cano, Panayiotis Tsokas, James E Cottrell, André Antonio Fenton, Harel Shouval, Todd Charlton Sacktor

Faculty, Staff and Student Publications

How can the molecules that strengthen synaptic connections maintain memory in the face of molecular turnover? Our previous work showed that persistent interaction between the postsynaptic scaffolding protein, KIBRA, and the autonomously active PKC isoform, PKMζ, is crucial for maintaining synaptic long-term potentiation (LTP) and memory lasting at least a month. This duration is longer than the lifespans of individual KIBRA and PKMζ molecules. Biophysical modeling of the interaction suggests oligomers of KIBRA-PKMζ dimers, but not individual dimers or monomers, can overcome molecular turnover by continuously incorporating newly synthesized KIBRA and PKMζ, replacing those that have degraded. Here we used …

Bi-Allelic Variants In Nrdc Cause A Neurodevelopmental Disorder Characterized By Neonatal Lethality, Microcephaly, And Brain Abnormalities, Davut Pehlivan, Abigail Sandoval, Reza Maroofian, François Lecoquierre, Aisha M Al Shamsi, Gyu S Lee, Osman Yesilbas, Preston Taylor, Matthew B Mcdougal, Vahid Bahrambeigi, Omid Aryani, Juan Felipe Ramirez, Khalid Hama Salih, Chadi Al Alam, Heba Morsy, Haytham Hussien, Tarek Omar, Ibrahim M Abdelrazek, Anne Claire Brehin, Dana Marafi, Tugba Kalayci, Jubran Abu Rahma, Jawabreh Kassem Talbeya, Husein Dabbah, Eric Verspyck, Toktam Moosavian, Jawid M Fatih, Tadahiro Mitani, Gulsen Akay, Daniel G Calame, Anne-Marie Guerrot, Wendy K Chung, Henry Houlden, James R Lupski, Adel Shalata, Wan Hee Yoon

Faculty, Staff and Students Publications

Nardilysin (NRDC) plays a role in multiple cellular functions in diverse cellular compartments, including ectodomain shedding in the plasma membrane, as well as chaperoning a key Krebs cycle enzyme in mitochondria. We had previously reported limited clinical information from two individuals with homozygous frameshift variants in NRDC. With inclusion of previously published individuals, here we report 14 individuals (10 females, four males) from nine unrelated families carrying homozygous NRDC pathogenic variants. Common clinical features include severe to profound developmental delay/intellectual disability (12/12), microcephaly (13/13), prematurity (5/13), lethality in the first 3 years of life (9/14), seizures (7/11), joint contractures (4/8), …

Poly(Adp-Ribose) Glycohydrolase Enforces P21 Degradation Via Deparylation To Promote Gastric Cancer Progression, Yangchan Hu, Qimei Bao, Yixing Huang, Yan Wang, Xin Zhao, Junjun Nan, Yuxin Meng, Mingcong Deng, Yuancong Li, Zirui Zhuang, Hanyi He, Dan Zu, Yuke Zhong, Chunkai Zhang, Bing Wang, Ran Li, Yanhua He, Qihan Wang, Min Liu, John A Tainer, Yin Shi, Xiangdong Cheng, Ji Jing, Zu Ye

Faculty, Staff and Student Publications

Dysregulation of cell cycle checkpoints is a cancer hallmark, with ubiquitination-controlled protein stability playing a pivotal role. Although p21, a key cyclin-dependent kinase inhibitor, is tightly regulated by ubiquitin-mediated degradation, the key upstream modulators of its ubiquitination remain incompletely defined. Here, we identify poly(ADP-ribose) glycohydrolase (PARG) as a regulator of p21 stability in gastric cancer (GC) cells. We show that PARG expression is markedly upregulated in GC tissues and correlates with poor patient prognosis. Functional assays revealed that genetic depletion of PARG triggers G2/M phase arrest and impairs GC cell proliferation. Mechanistically, we demonstrate that PARG loss enhances p21 PARylation, …

Mechanometabolism Instructs Hematopoietic Stem Cell Specification, Paulina D Horton, Alina Syed, Michelle Winkler, Abishek B Vaidya, Michael Rariden, Neha Arora, Yong Zhou, Michihiro Kobayashi, Momoko Yoshimoto, Hyun Jung Lee, Hyun-Eui Kim, John P Hagan, Catherine Denicourt, Travis I Moore, Pamela L Wenzel

Faculty, Staff and Student Publications

Mechanical force generated by blood flow stimulates emergence of the first hematopoietic stem cells (HSCs) that populate the blood system. Force drives the transition of HSC precursors from an endothelial to hematopoietic identity, yet the molecular regulation of this fate switch remains poorly understood. We report that shear stress triggers adaptation in mitochondrial composition, ultrastructure, and function, which are essential for hematopoietic fate and engraftment potential. Shear stress remodels mitochondria in hemogenic endothelium by promoting mitochondrial gene transcription and protein synthesis. Laminar flow selectively initiates translation of 5' terminal polypyrimidine (5'TOP) motif-containing transcripts, which commonly encode ribosome and translation machinery. …

Ectopic B Lymphocyte Follicles Exacerbate Ischemic Brain Damage Via Mif-Cd74/Cxcr4 And Interferon Signaling, Sheng Yang, Hang Zhang, Lu-Lu Xu, Luo-Qi Zhou, Yun-Hui Chu, Lian Chen, Xiao-Wei Pang, Lu-Yang Zhang, Li-Fang Zhu, Ming-Hao Dong, Ke Shang, Jun Xiao, Long-Jun Wu, Wei Wang, Dai-Shi Tian, Chuan Qin

Faculty, Staff and Student Publications

Neuroinflammation, encompassing both innate and adaptive immune responses, plays a crucial role in ischemic stroke. Although B lymphocytes are central to adaptive immunity, their contributions to ischemic stroke remain poorly understood. Here, we demonstrated that B lymphocytes accumulate in ischemic lesions, forming germinal center-like structures at the later stage after stroke, which mainly depended on in situ proliferation. This accumulation correlated with worsened neuroinflammation and ischemic injury, whereas B cell depletion reduced chronic brain damage during stroke. Mechanistically, microglia recruited B cells into ischemic lesions through MIF-CD74/CXCR4 signaling during the early phase of stroke, while IFN-related pathways in B cells …

Non-Synaptic Function And Localization Of Syntaxin-Binding Protein 1 In A Mouse Model Of Stxbp1-Related Epileptic Encephalopathy, Tao Yang, Rajat Banerjee, Yamei Deng, Sheetal Jahagirdar, Joo Hyun Kim, Wu Chen, Mingshan Xue, Alexey I Nesvizhskii, Michael D Uhler, Jack M Parent, Yu Wang

Duncan NRI Faculty and Staff Publications

Objective: De novo mutations in the syntaxin-binding protein 1 (STXBP1), encoded by STXBP1, are among the most prevalent causes of variable neurodevelopmental disorders, including epileptic encephalopathy, developmental delay, and movement disorders. Although STXBP1 has been proposed as a critical presynaptic protein controlling synaptic vesicle exocytosis, clinical phenotypes also suggest that its biological function could be more diverse.

Methods: The expression pattern of STXBP1 was studied using immunostaining in vitro and in vivo. Synaptosome isolation was performed to investigate the synaptic and non-synaptic localization of STXBP1 in the brain. STXBP1 immunoprecipitation followed by mass spectrometry (MS) was conducted to identify protein …

Pharmacokinetic Modeling Strategies For Dynamic Hyperpolarized Urea Imaging, Keith A Michel, Collin J Harlan, Christopher M Walker, Matthew E Merritt, Yunyun Chen, Stephen Y Lai, James A Bankson

Faculty, Staff and Student Publications

Purpose: To evaluate pharmacokinetic modeling methods for quantification of tissue perfusion/permeability with hyperpolarized 13C urea.

Methods: Three models for quantitative analysis of dynamic HP urea imaging data were proposed and evaluated in numerical simulations and a thyroid cancer mouse model. A multicompartment model resembling the extended Tofts model for DCE-MRI (Model I) and two simplified models were used. The simplified models each eliminate a volume parameter representing vascular (Model II) or impermeable cellular space (Model III). Signal curves were generated from Model I, and models were fit to these synthetic data to quantify the effects of acquisition settings, bias in …

Alpha 7 Nicotinic Acetylcholine Receptor Contributes To Long-Term Cognitive Recovery Following Ischemic Stroke, Dustin T Nguyen, Kate Mendoza, Cassandra Hall, Chunfeng Tan, Anjali Chauhan

Faculty, Staff and Student Publications

Stroke is associated with autonomic dysfunction and reduced acetylcholine (ACh), a neurotransmitter critical for cognition. ACh signals in part through the alpha-7 nicotinic acetylcholine receptor (α7nAChR), a ligand-gated ion channel involved in synaptic plasticity, learning, and memory. Impaired α7nAChR signaling has been linked to heightened neuroinflammation and poor acute stroke recovery. Here, we investigated whether α7nAChR contributes to post-stroke cognitive recovery in young male mice. Wild-type (WT) and α7nAChR knockout (α7n0KO) mice underwent 60-min middle cerebral artery occlusion (MCAO). In a pharmacology cohort, the α7nAChR agonist GTS-21 was administered immediately after reperfusion and then daily for 20 days. Cognitive performance …

Beyond Short Microhomologies: Mismatch-Compatible Pol Θ-Mediated Dna Damage Repair, Yuzhen Li, Richard D Wood

Faculty, Staff and Student Publications

DNA polymerase θ (Pol θ)-mediated end-joining (TMEJ), one of several pathways for repairing DNA double-strand breaks, is traditionally thought to initiate via anchoring at short, consecutive, and perfectly matched microhomologies (MHs). Emerging evidence indicates that Pol θ can utilize MHs containing mismatches both in vitro and in vivo. This revised definition of MH provides a mechanistic explanation for a broader spectrum of Pol θ-dependent repair outcomes. Here, we summarize recent findings on the revised definition of MHs utilized by Pol θ, assess the applicability of this concept across species, and compare TMEJ with other (micro)hom(e)ology-mediated repair pathways. We explore how …

Selective Deletion Of Fgfr1 In Agrp Neurons Impairs Energy Homeostasis Under High-Fat Diet In Mice, Daniel Shookster, Shea O'Connell, Patel Darshan, Taylor Landry, Wyatt Bunner, Zhiying Jiang, Qingchun Tong, Hu Huang

Faculty, Staff and Student Publications

Background: The global obesity crisis and the limited success of current treatments underscore the need to identify novel regulatory pathways. While central administration of α-Klotho exerts anti-obesity effects in rodents through AgRP neurons, the intracellular signaling mechanisms that mediate this process remain undefined.

Methods: To define the role of FGFR1 within the α-Klotho signaling pathway in AgRP neurons, we performed a targeted deletion of the receptor in adult mice using an AAV-mediated CRISPR/Cas9 system alongside transgenic models.

Results: Deletion of FGFR1 in AgRP neurons disrupted energy homeostasis, promoting weight gain induced by a high-fat diet. Electrophysiological recordings revealed that FGFR1 …

Cd44v9 As A Therapeutic Target For Antibody-Drug Conjugate In Advanced Breast Cancer, Dileep R Reddy, Mckenna E Flynn, Yasuaki Anami, Zhaoxuan Yang, Jayden Aleman, Minji Seo, Kyoji Tsuchikama, Jennifer A Maynard, Naoto T Ueno, Jangsoon Lee

Faculty, Staff and Student Publications

Antibody-drug conjugates (ADCs) have revolutionized breast cancer therapy. HER2 is the only validated biomarker guiding ADC therapy in breast cancer. However, their clinical benefit remains confined to HER2- and TROP2-targeted therapies. Tumor heterogeneity and acquired resistance often limit durable responses, underscoring the need for novel, tumor-specific ADC targets. CD44 variant isoform 9 (CD44v9), a splice variant of the CD44 family, is largely absent in normal tissues but enriched in aggressive breast cancers, where it contributes to stemness, redox regulation, and therapy resistance. In this study, we developed a chimeric monoclonal antibody against CD44v9 (clone SUM24.1, IgG1) and conjugated it to …

Fgl2-Knockout Tumor Cells Serve As A Vaccine Inducing Long-Duration Brain-Resident Memory T Cells That Reject Subsequent Intracranial Tumor Cell Challenges, Sheng Zhang, Yining Jin, Zhiliang Jia, Xueqing Xia, Yang Li, Qi Wang, Jing Wang, Jian Wang, Joya Chandra, Gregory K Friedman, Shulin Li

Faculty, Staff and Student Publications

The failure to prevent brain tumors, including both recurrent primary and metastatic brain tumors, is the primary cause of patients' mortality. We developed a novel whole tumor-cell vaccine to rapidly induce long-duration brain-resident memory T (TRM) cells that prevent brain tumor progression. Ten Fgl2-KO primary and metastatic tumor cell lines, generated via CRISPR/Cas9, were used to vaccinate mice and for intracranial challenges with the WT tumor cells. Not only did vaccinated mice reject these tumor cell challenges, but also more than half of these mice became long-duration survivors. Transplanting brain immune cells from vaccinated mice into naïve mice enabled this …