Medical Sciences Commons^™

A Mouse Model Of Lipoatrophy Reveals Relationships Between Beige Fat Appearance And Female Fertility, Elizabeth S Anaya, William Dion, Pradip K Saha, Aaron R Cox, Evelyn De Groot, Avery A Ahmed, Jessica B Felix, Bokai Zhu, Stephanie A Pangas, Sean M Hartig

Faculty, Staff and Students Publications

White adipose tissue (WAT) performs vital metabolic and endocrine functions, but roles in female reproduction remain understudied and poorly understood. Here, we report that female mice experiencing progressive lipoatrophy after knockout of Ubc9 in adipocytes (Ubc9fKO) displayed disrupted estrous cycles, reduced ovarian reserve, and subfertility. During aging, female Ubc9fKO mice lose subcutaneous WAT more quickly than their male counterparts and weigh less than littermate controls. Subcutaneous WAT excised from female Ubc9fKO mice strongly enriched for thermogenesis genes generally associated with metabolic benefits. Female Ubc9fKO mice exhibited hypermetabolism and accumulated thermogenic, Uncoupling Protein 1-expressing beige fat cells in residual subcutaneous WAT …

Fgf13 Regulates Vgsc-Independent Cardiomyocyte Impulse Propagation Via Cx43 Trafficking, Lala Tanmoy Das, Mattia Malvezzi, Aravind R Gade, Maiko Matsui, Margaret Mckay, Eric Q Wei, Matea J Zelich, Keon Mazdisnian, Jared Kushner, Bi-Xing Chen, Isabella Distefano, Daniel Roybal, Lin Yang, Lisa Stoll, James C Lo, Marian Kalocsay, Fadi G Akar, Steven O Marx, Geoffrey S Pitt

Faculty, Staff and Student Publications

Background: FHF (fibroblast growth factor homologous factor) variants associate with arrhythmias. Although FHFs are best characterized as regulators of voltage-gated sodium channel (VGSC) gating, recent studies suggest broader, non-VGSC-related functions, including regulation of Cx43 (connexin 43) gap junctions and hemichannels, mechanisms that have generally been understudied or disregarded.

Methods: We assessed cardiac conduction and cardiomyocyte action potentials in mice with constitutive cardiac-specific Fgf13 ablation (cFgf13KO) while targeting Cx43 gap junctions and hemichannels pharmacologically. We characterized FGF13 regulation of Cx43 abundance and subcellular distribution. With proximity labeling proteomics, we investigated novel candidate mechanisms underlying FGF13 regulation of Cx43. …

Protein-Protein Interaction–Interfering Peptide Rescues Dysregulated Nmda Receptor Signaling, Robert E. Featherstone, Hongbin Li, Ameet S. Sengar, Karin E. Borgmann-Winter, Olya Melnychenko, Lindsey M. Crown, Ray L. Gifford, Felix Amirfathi, Anamika Banerjee, Aivi Tran, Krishna Parekh, Margaret Heller, Wenyu Zhang, Robert J. Gallop, Adam D. Marc, Pragya Komal, Michael W. Salter, Steven J. Siegel, Chang-Gyu Hahn

Farber Institute for Neuroscience Faculty Papers

The complex and heterogeneous genetic architecture of neuropsychiatric illnesses compels us to look beyond individual risk genes for therapeutic strategies and target the interactive dynamics and convergence of their protein products. A mechanistic substrate for convergence of synaptic neuropsychiatric risk genes are protein-protein interactions (PPIs) in the N-methyl-D-aspartate receptor (NMDAR) complex. NMDAR hypofunction in schizophrenia is associated with hypoactivity of Src kinase, resulting from convergent alterations in PPIs of Src with its partners. Of these, the association of Src with PSD-95, which inhibits the activity of this kinase in the NMDAR complex, is known to be increased in schizophrenia. Here, …

Restoration Of Sfrp3 Preserves The Neural Stem Cell Pool And Spatial Discrimination Ability In A Mouse Model Of Alzheimer's Disease, Chia-Hsuan Fu, Jin Park, Umberto Tosi, Francisco A Blanco, Manuel Silva-Pérez, Kavitha Muralidharan, Jason C You, Minjung Lee, Gabriel S Stephens, Xiaohong Zhang, Yi Zheng, Helen Scharfman, Kimberley F Tolias, Jeannie Chin

Faculty, Staff and Students Publications

Individuals with Alzheimer's disease (AD) have an increased incidence of seizures, which worsen cognitive decline. Using a transgenic mouse model of AD neuropathology that exhibits spontaneous seizures, we previously found that seizure activity stimulates and accelerates depletion of the hippocampal neural stem cell (NSC) pool, which was associated with deficits in neurogenesis-dependent spatial discrimination. However, the precise molecular mechanisms that drive seizure-induced activation and depletion of NSCs are unclear. Here, using mice of both sexes, we performed RNA-sequencing on the hippocampal dentate gyrus and identified differentially expressed regulators of neurogenesis in the Wnt signaling pathway that regulates many aspects of …

A Distinct Pp2a Subunit Regulates Local Protein Phosphorylation At The Axon Initial Segment, Andrew P Anderson, Sanghyun Kim, Allison J Melton, Xiaoyun Ding, Wei Zhang, Alexander B Saltzman, Anna Malovannaya, Matthew N Rasband, Yudong Gao

Faculty, Staff and Students Publications

Protein phosphorylation plays a crucial role in regulating the cytoskeletal and membrane proteins at the axon initial segment (AIS). However, our knowledge of AIS-specific kinases and phosphatases is very limited. Here, we report the identification of a protein phosphatase 2A (PP2A) B55 regulatory subunit enriched at the AIS in mice: Ppp2r2c. Our results demonstrate that PP2A-B55 subunits exhibit substantial heterogeneity in their subcellular localization and function. Notably, the Ppp2r2c subunit is selectively concentrated at the AIS, and this enrichment is driven by its unique structure. Utilizing a microelectrode array system (MEA), we show that Ppp2r2c modulates neuronal activity during in …

Revisiting Soluble Guanylate Cyclase Pharmacology: Additive Potential Of Stimulators And Activators, Alexandra Petraina, Mahmoud H Elbatreek, Christopher T Neullens, Theodora Saridaki, Vu Thao-Vi Dao, Rebecca D Szepanowski, Emil Martin, Wolfgang Sippl, Ana I Casas, Harald H H W Schmidt

Faculty, Staff and Student Publications

Nitric oxide (NO) is a key gasotransmitter that binds to soluble guanylate cyclase (sGC), thereby stimulating cGMP production. Under disease conditions, reactive oxygen species disrupt this signaling by either: (1) scavenging NO, or (2) promoting heme-free, NO-insensitive apo-sGC due to impaired heme incorporation or oxidative damage. To counteract these conditions, two pharmacological approaches have emerged: sGC stimulators, which allosterically enhance sGC sensitivity to low NO levels; and sGC activators, which directly activate apo-sGC (heme-free sGC) by binding to its empty heme pocket, inducing a conformation that mimics NO-bound sGC. Thus, sGC stimulators are thought to target only sGC. Instead, we …

Method For Generation And Ex Vivo Expansion Of Genetically Edited Mouse Tregs, Yosef Gilad, Adam M Dean, Yan Xia, Sang Jun Han, David M Lonard, Bert W O'Malley

Faculty, Staff and Students Publications

Regulatory T cells (Tregs) play a crucial role in the immune system, and their dysfunction can lead to the development of autoimmune conditions. In cancer, tumors frequently hijack the immunosuppressive function of Tregs to evade immune responses. Due to their central role in key pathological processes, Tregs have gained increasing attention as promising targets for various clinical applications. However, their relative scarcity (∼5% to 10% of CD4+ T cells) and instability presents a technical challenge for research and therapeutic development. In congenic animal models used to investigate autologous cell transfer-based therapies, this challenge is even greater, as Treg donor animals …

Gene Therapy Cm-Yapon Protects The Mouse Heart From Myocardial Infarction, Fansen Meng, Jeffrey D Steimle, Elizabeth Straight, Rich G Li, Yuka Morikawa, Zohaib Iqbal, Bing Xie, Jun Wang, Wyatt G Paltzer, Yi Zhao, Chang-Ru Tsai, Lin Liu, Maggie Lim, Rita A Schack, Daniel Ramirez, Katherine Carlson, Vaibhav Deshmukh, Jason M Karch, Robia G Pautler, Xiao Li, James F Martin

Faculty, Staff and Students Publications

Myocardial infarction (MI) affects millions of people worldwide, causing irreversible injury to the heart and impairing cardiac function1. In both mouse and pig MI models, activating YAP in cardiomyocytes (CMs) stimulates regenerative repair2,3. Here we developed an adeno-associated virus 9 (AAV9)-based therapy, termed CM-YAPon, which enables transient expression of an active YAP variant (YAP5SA) in CMs following exposure to the small molecule LMI070. A single LMI070 dose in mice triggers YAP5SA expression, CM cell cycle re-entry, and reprogramming of the cardiac microenvironment. YAP5SA induction after MI rapidly improves cardiac function while pre-MI induction confers …

Ataxia-Telangiectasia Mutated Activation Mediates Transforming Growth Factor Beta Signaling In Acetaminophen-Induced Liver Injury In Mice, Matthew Mcmillin, Christopher S Chu, Elaina Williams, Juliet Venter, Kiersten Bell, Anca D Petrescu, Patrick Mireles, Sharon Demorrow

Faculty and Staff Publications

Acetaminophen (APAP) overdose is associated with increased transforming growth factor beta 1 (TGFβ1) signaling and elevated oxidative stress, which exacerbate DNA damage. TGFβ1 has been shown to regulate ataxia-telangiectasia mutated (ATM) signaling and DNA repair in other cell types. This study investigates the DNA damage response (DDR) during APAP-induced liver injury, focusing on ATM-mediated regulation of TGFβ1 signaling. APAP administration in vitro and in vivo resulted in DNA damage, increased ATM signaling, accumulation of γH2AX, and activation of phosphorylated ataxia telangiectasia mutated (pATM) and phosphorylated checkpoint kinase 2 (pChk2). Pretreatment with an ATM inhibitor, KU55933, attenuated APAP-induced hepatocyte damage and …

Secretory Iga Dysfunction Underlies Poor Prognosis In Fusobacterium-Infected Colorectal Cancer, Ilseok Choi, Kyung-A Kim, Sang Cheol Kim, Donghwan Park, Ki Taek Nam, Jun Hyung Cha, Seungbyn Baek, Junha Cha, Hye-Yeong Jo, Minsun Jung, Melody Y Zeng, Irina Matei, Susan Bullman, Joong Bae Ahn, Yoon Dae Han, Han Sang Kim, Insuk Lee

Faculty, Staff and Student Publications

Fusobacterium nucleatum (Fn) is commonly enriched in colorectal cancer (CRC) and associated with poor outcomes, though its mechanisms remain unclear. Our study investigated how Fn affects the tumor microenvironment through single-cell transcriptomic analyses of 42 CRC patient tissues, comparing Fn-positive and Fn-negative tumors. We discovered that Fn impairs IgA plasma cell development and secretory IgA (sIgA) production by disrupting communication with tumor-associated macrophages. Additional experiments in germ-free mice, together with our re-analysis of a publicly available single-cell RNA-seq data set from a CRC mouse model with an intact gut microbiome–both models having been orally gavaged with Fn–jointly validated the causal …

Decoding Fibrosis In Nonresolvable Covid-19: A Role For Myeloid-Specific Hif1a Deletion, Kemly Philip, Hannah P Thompson, Scott D Collum, Isabella Lefebvre, Bindu Akkanti, Bihong Zhao, Rahat Hussain, Manish Patel, Michael R Blackburn, Tingting W Mills, Harry Karmouty-Quintana

Faculty, Staff and Student Publications

A complication of viral lung infections is the development of pulmonary fibrosis. This phenomenon is most evident in patients with COVID-19, where in its most aggressive form patients developed nonresolvable (NR) COVID-19 requiring lung transplantation. NR-COVID-19 was characterized by the presentation of a fulminant fibrotic lung injury that progressed rapidly, even in patients with limited comorbidities. However, the mechanisms that led to this rapidly progressing form of fibrosis are not fully understood. A common clinical manifestation in the most severe cases of COVID-19 was the presence of "silent" hypoxemia. Thus, we hypothesized that a dysfunctional hypoxic response may result in …

Differential Effects Of Murine Stroke Models On Dopaminergic Neurons, Glial Responses, And Neurobehavioral Outcomes, Sidra Tabassum, Heng Hu, Silin Wu, Shuning Huang, Bosco Seong Kyu Yang, Chang-Hun Lee, Aaron W Gusdon, Xuefang S Ren

Faculty, Staff and Student Publications

Stroke is a leading cause of disability worldwide, often resulting in persistent motor, cognitive, and emotional impairments. While the hippocampus and amygdala play critical roles in post-stroke behavioral changes, specific neuronal alterations and prolonged glial responses within these regions across different stroke types remain unclear. This study investigates the behavioral, neuronal, and glial effects of subarachnoid hemorrhage (SAH), transient middle cerebral artery occlusion (tMCAO), and photothrombotic stimulation (PTS) in mice. SAH and tMCAO models exhibited significant motor deficits, spatial and recognition memory impairments, and increased anxiety- and depressive-like behaviors, whereas the PTS model showed similar motor and cognitive impairments but …

Inhibiting Monocyte Migration Reduces Arterial Thrombosis And Facilitates Thrombolysis, Hee Jeong Jang, Jiwon Kim, Ha Kim, Taesu Kim, Jinyong Chung, Sebastian Cremer, Marvin Krohn-Grimberghe, Eo Jin Kim, Dawid Schellingerhout, Matthias Nahrendorf, Dong-Eog Kim

Faculty, Staff and Student Publications

Background: Monocytes contribute to the initiation and propagation of venous thrombosis. Little is known about the roles monocytes play in arterial thrombosis, the cause of stroke and myocardial infarction.

Methods: We investigated how CCR2 (CC chemokine receptor 2) knockout (-/-)-mediated monocyte deficiency affects platelet function, blood coagulation, thrombus volume, and thrombolytic susceptibility in 666 male mice with FeCl3-mediated carotid arterial thrombosis, including 365 C57BL/6 wild type (WT) mice, 295 CCR2-/- mice, and 6 CX3CR1-GFP (CX3C chemokine receptor 1-green fluorescent protein) mice.

Results: Intravital microscopy and flow cytometry showed that both neutrophils and monocytes were recruited to the acute arterial thrombus, …

Impact Of Peripheral Circadian Misalignment And Alcohol On The Resiliency Of Intestinal Barrier And Microbiota, Laura Tran, Maliha Shaikh, Phillip A Engen, Ankur Naqib, Dulce M Frausto, Vivian Ramirez, Malia Gasteier, Zlata Bogin, Kristi Lawrence, Lijuan Zhang, Shiwen Song, Stefan J Green, Faraz Bishehsari, Christopher B Forsyth, Ali Keshavarzian, Garth R Swanson

Faculty, Staff and Student Publications

Circadian organization is involved in many gastrointestinal tract (GIT) functions such as the maintenance of intestinal barrier integrity. There is compelling evidence that perturbation of the circadian clock decreases intestinal epithelial cells' resiliency to alcohol-induced injury. One of the most common causes of circadian misalignment is wrong-time eating (largest meal at dinner) in modern societies. Yet, few studies have examined the importance of peripheral circadian rhythms of the GIT to alcohol consumption. Eating patterns during physiologic rest time, defined as wrong-time eating (WTE), misalign the peripheral circadian clock of the GIT and the body's central clock. This study aims to …

Ddt Exposure Induces Microglial Activation And Disease-Associated Microglial Signatures: Relevance To Mechanisms Of Alzheimer’S Disease, Isha Mhatre-Winters, Aseel Eid, Nicole Blum, Yoonhee Han, Ferass M Sammoura, Long-Jun Wu, Jason R Richardson

The Brown Foundation: Institute of Molecular Medicine

Background: Alzheimer's disease (AD) is characterized by the presence of amyloid-β plaques, neurofibrillary tangles, and neuroinflammation. Previously, we reported that serum levels of dichlorodiphenyldichloroethylene (DDE), the primary metabolite of the pesticide dichlorodiphenyltrichloroethane (DDT), were significantly higher in AD patients compared to age-matched controls and that DDT exposure worsened AD pathology in animal models.

Objective: Here, we investigated the effect of DDT on neuroinflammation in primary mouse microglia (PMG) and C57BL/6J mice.

Methods: DDT-induced inflammatory and disease-associated microglial (DAM) gene expression were determined in PMG by qPCR and immunocytochemistry, with and without pretreatment with the sodium channel antagonist tetrodotoxin (TTX). Furthermore, …

Surgical Removal Of Implanted Microchips To Correct Mri Susceptibility Artifacts In Mice, Elizabeth Hipskind, Nicole Hernandez, Sydney Fox, Tina Manirambona, Rita Schack, Brian Gibson, Robia G Pautler

Center on Aging Staff Publications

Purpose: Implanted microchips are becoming increasingly common in research for animal identification and have been adopted by commercial vendors for some mouse strains. However, they often contain metal components, which generate magnetic susceptibility artifacts on MR images. Despite this, some microchips are marketed as MR-compatible, even though they are likely to affect image quality.

Methods: We assessed the impact of a radiofrequency identification microchip on MR images of the mouse brain and present a method for precise surgical removal. A handheld magnet was used to locate and stabilize the microchips during removal. Mice were imaged before and after microchip removal. …

Cerebellar Purkinje Cell Stripe Patterns Reveal A Differential Vulnerability And Resistance To Cell Loss During Normal Aging In Mice, Sarah G Donofrio, Cheryl Brandenburg, Amanda M Brown, Tao Lin, Hsiang-Chih Lu, Roy V Sillitoe

Faculty, Staff and Students Publications

Age-related neurodegenerative diseases involve reduced cell numbers and impaired behavioral capacity. Neurodegeneration and behavioral deficits also occur during aging, and notably in the absence of disease. The cerebellum, which modulates movement and cognition, is susceptible to cell loss in both aging and disease. Here, we demonstrate that cerebellar Purkinje cell loss in aged mice is not spatially random but rather occurs in a pattern of parasagittal stripes. We also find that aged mice exhibit impaired motor coordination and more severe tremor compared to younger mice. However, the relationship between patterned Purkinje cell loss and motor dysfunction is not straightforward. Examination …

Characterizing The Metabolites Of The Tyrosine-Kinase Inhibitor Pexidartinib In Mouse Feces, Urine, Plasma, And Liver, Xuan Qin, Si Chen, John M Hakenjos, Jian Wang, Lei Guo, Ashish Dogra, Zhaoyong Hu, Kevin R Mackenzie, Feng Li

Faculty, Staff and Students Publications

Pexidartinib (PEX, TURALIO®), a tyrosine kinase inhibitor, is approved for treating tenosynovial giant cell tumor in adults. However, its potential to cause fatal liver injury has prompted the U.S. FDA to issue a black box warning, and the mechanisms underlying its hepatotoxicity remain largely unknown. As biotransformation may contribute to PEX-induced hepatotoxicity, understanding its metabolism is essential. Our previous research indicated that PEX forms reactive metabolites in human and mouse liver microsomes and in human hepatocytes. We investigated PEX metabolism and liver distribution in mice with a focus on metabolite characterization. Our data shows that PEX is mainly excreted into …

Reprogramming Tumor Microenvironment Via Systemic Delivery Of Tlr3 Agonist And Manganese Nanoparticle, Young Seok Cho, Xingwu Zhou, Xiaoqi Sun, Ziye Wan, Julia Crowther, Mariko Takahashi, Swetha Kodamasimham, Qi Wu, May Thazin Phoo, Youngseo Na, Kai Han, Zaiye Li, Anna Schwendeman, Steven P Schwendeman, Yu Leo Lei, James J Moon

Faculty, Staff and Student Publications

Toll-like receptor (TLR) agonists, as potent immunostimulatory adjuvants, play a critical role in linking the innate and adaptive immune responses. However, their antitumor effects as cancer immunotherapeutic agents have been limited. Here, we report our finding that manganese ion (Mn2+) potentiates various TLR agonists, leading to robust activation of the TLR pathway and the stimulator of interferon genes (STING) pathway among innate immune cells. In particular, we have observed robust antitumor efficacy after intratumoral administration of a TLR3 agonist and Mn2+. To achieve systemic codelivery of TLR3 agonist and Mn2+, we have developed a low-molecular-weight poly(inosinic:cytidylic acid)-Mn2+ coordination lipid nanoparticle …

Cofilin Inhibition Ameliorates Piezo2 And Ampa Dysfunction In A Mouse Model Of Angelman Syndrome, Luis O Romero, Manisha Bade, Elisa Carrillo, Sonia Paz-López, Syed A M Hasan, William James Antonisamy, Vasanthi Jayaraman, Zahoor A Shah, Valeria Vásquez, Julio F Cordero-Morales

Faculty, Staff and Student Publications

Angelman syndrome (AS) is a neurogenetic disorder characterized by motor coordination and cognitive deficits. In AS, hippocampal neurons show reduced filamentous (F-)actin, a decrease we also reported in dorsal root ganglia (DRG) neurons, along with impaired mechanosensitive ion channel activity. Currently, there are no pharmacological targets to prevent the decrease of F-actin in AS. Here, we utilize a first-in-class selective cofilin inhibitor (SZ-3) to restore PIEZO2 function in DRG neurons and glutamate-evoked currents in hippocampal neurons from AS mice. Using atomic force microscopy, we demonstrate that inhibiting cofilin, an actin-severing protein, with SZ-3 increases cellular stiffness by stabilizing the actin …

Targeting Adenosine 2a Receptor Signaling Suppresses Vascular Calcification By Restraining Smooth Muscle Osteogenic Differentiation, Yaqi Zhou, Dingwei Zhao, Qian Ma, Sujin Lee, Kangsan Roh, Yongfeng Cai, Jiean Xu, Qiuhua Yang, Qingen Da, Zhiping Liu, Kunfu Ouyang, Eric J Belin De Chantemele, Mei Hong, Clint L Miller, Rajeev Malhotra, Chunxiang Zhang, Suowen Xu, Yuqing Huo

Faculty, Staff and Students Publications

Vascular calcification (VC) is a major contributor to cardiovascular morbidity and mortality, particularly in patients with chronic kidney disease (CKD). Adenosine 2 A receptor (ADORA2A) is highly expressed in vascular cells and implicated in cardiovascular disease; however, its specific role in VC pathogenesis remains unclear. Here, we investigated the role of ADORA2A using in vitro (vascular smooth muscle cells; VSMCs), ex vivo (mouse aortic rings), and in vivo (5/6th nephrectomy with high phosphate and cholecalciferol) models of VC. The ADORA2A expression was significantly upregulated in calcified human and murine aortic tissues, as well as in VSMCs, under osteogenic conditions. Genetic …

Endothelial Adenosine Receptor 2a Loss Alleviates Diabetic Vascular Calcification By Blocking Creb1-Snai1-Driven Endmt, Yaqi Zhou, Dingwei Zhao, Qian Ma, Jiean Xu, Yongfeng Cai, Qiuhua Yang, Qingen Da, Kian Sheridan, Chunxiang Zhang, Clint L Miller, Rajeev Malhotra, Suowen Xu, Mei Hong, Yuqing Huo

Faculty, Staff and Students Publications

Vascular calcification (VC), a common complication associated with diabetes mellitus (DM), substantially increases the risk of cardiovascular diseases and is associated with elevated mortality in individuals with DM. Endothelial-to-mesenchymal transition (EndMT) imparts phenotypic plasticity to vascular endothelial cells (VECs), granting them the potential for osteogenic differentiation, which is a crucial mechanism in regulating VC. Notably, adenosine-ADORA2A-mediated endothelial dysfunction plays a pivotal regulatory role in cardiovascular diseases. However, the specific role of endothelial ADORA2A in diabetic VC remains to be elucidated. In this study, we found that ADORA2A was upregulated in the endothelium of diabetic mice and cultured human aortic endothelial …

Perfluoroalkyl Substance Pollutants Disrupt Microglia Function And Trigger Transcriptional And Epigenomic Changes, Yating Cheng, Jian-Rong Li, Hangjin Yu, Shuang Li, Boranai Tychhon, Chao Cheng, Yi-Lan Weng

Faculty, Staff and Students Publications

Per- and polyfluoroalkyl substances (PFAS), commonly referred to as "forever chemicals", are widely utilized in various industries and consumer products worldwide. Their exposure has been associated with numerous diseases and malignancies, including neurodevelopmental and neurodegenerative disorders. However, the molecular mechanisms underlying PFAS-induced adverse effects on the central nervous system (CNS) remain poorly understood. In this study, we investigated the transcriptomic and epigenetic changes in microglia exposed to perfluorooctane sulfonate (PFOS), a prevalent PFAS compound. Our findings demonstrate that 24-hour PFOS exposure (25 and 50 µM) disrupts the microglial transcriptome and compromises their homeostatic state, marked by increased inflammation and impaired …

Pkr-Driven Isr Signaling Controls Synaptic Translation And Structural Plasticity In An Age-Dependent Manner, Nicolás W Martínez, Felipe Gómez, Ariel Tapia-Godoy, Juan Francisco Roa, Fernanda Moreso-Contreras, Yuwei Liu, Claudia Jara, Cheril Tapia-Rojas, Iván Alfaro, Mauro Costa-Mattioli, Soledad Matus

Faculty, Staff and Students Publications

The integrated stress response (ISR) modulates protein homeostasis in response to both intracellular and extracellular signals. The four kinases involved in the ISR all phosphorylate the same target, the alpha subunit of eukaryotic initiation factor 2 (eIF2α), to integrate various stress signals, thereby regulating cell fate. The activation of the ISR reprograms the proteome by inhibiting general protein synthesis while increasing the translation of specific mRNAs. In the brain, the ISR regulates the type of synaptic plasticity necessary for forming long-term memory. More importantly, the activation of the ISR has emerged as a causal mechanism underlying cognitive decline associated with …

Glycerol-3-Phosphate Activates Chrebp, Fgf21 Transcription And Lipogenesis In Citrin Deficiency, Vinod Tiwari, Byungchang Jin, Olivia Sun, Edwin D J Lopez Gonzalez, Min-Hsuan Chen, Xiwei Wu, Hardik Shah, Andrew Zhang, Mark A Herman, Cassandra N Spracklen, Russell P Goodman, Charles Brenner

Faculty, Staff and Students Publications

Citrin deficiency (CD) is caused by the inactivation of SLC25A13, a mitochondrial membrane protein required to move electrons from cytosolic NADH to the mitochondrial matrix in hepatocytes. People with CD do not like sweets. Here we show that SLC25A13 loss causes the accumulation of glycerol-3-phosphate (G3P), which activates the carbohydrate response element-binding protein (ChREBP) to transcribe FGF21, which acts in the brain to restrain intake of sweets and alcohol and to transcribe key genes driving lipogenesis. Mouse and human data suggest that G3P-ChREBP is a mechanistic component of the Randle Cycle that contributes to metabolic-dysfunction-associated steatotic liver disease and forms …

Multiomic And Electrophysiologic Analyses Reveal That An Inherited Mrc2 Variant Causes Fibroblast Dysfunction And Increased Atrial Fibrillation Susceptibility, Kevin S Ho, Joshua A Keefe, Shuai Zhao, Mohit M Hulsurkar, Sung Yun Jung, Md Abul Hassan Samee, Xander H T Wehrens

Faculty, Staff and Students Publications

A recent study identified a rare variant in the mannose receptor C type 2 (MRC2) gene in individuals with familial reentrant supraventricular tachycardia, a Wolff-Parkinson-White (WPW) electrocardiogram pattern, and structurally normal hearts. WPW syndrome is associated with atrial fibrillation (AF), and MRC2 was recently proposed as a protective gene for AF. We determined whether the E990G-heterozygous (het) loss-of-function variant in Mrc2 increases AF susceptibility and identified aberrant cellular mechanisms resulting from Mrc2 deficiency in atrial cardiofibroblasts (ACFs) and atrial tissue in mice that may promote AF. Programmed electrical stimulation was performed to determine AF susceptibility in Mrc2 E990G-het …

Single-Nucleus Mrna-Sequencing Reveals Dynamics Of Lipogenic And Thermogenic Adipocyte Populations In Murine Brown Adipose Tissue In Response To Cold Exposure, Janina Behrens, Tongtong Wang, Christoph Kilian, Anna Worthmann, Mark A Herman, Joerg Heeren, Lorenz Adlung, Ludger Scheja

Faculty, Staff and Students Publications

Objective and methods: Brown adipose tissue (BAT) comprises a heterogeneous population of adipocytes and non-adipocyte cell types. To characterize these cellular subpopulations and their adaptation to cold, we performed single-nucleus mRNA-sequencing (snRNA-seq) on interscapular BAT from mice maintained at room temperature or exposed to acute (24h) or chronic (10 days) cold (6 °C). To investigate the role of the de novo lipogenesis (DNL)-regulating transcription factor carbohydrate response element-binding protein (ChREBP), we analyzed control and brown adipocyte-specific ChREBP knockout mice.

Results: We identified different cell populations, including seven brown adipocyte subtypes with distinct metabolic profiles. One of them highly expressed ChREBP …

Optic Nerve Injury Impairs Intrinsic Mechanisms Underlying Electrical Activity In A Resilient Retinal Ganglion Cell, Thomas E Zapadka, Nicholas M Tran, Jonathan B Demb

Faculty, Staff and Students Publications

Retinal ganglion cells (RGCs) are the sole output neurons of the retina and convey visual information to the brain via their axons in the optic nerve. Following injury to the optic nerve, RGCs axons degenerate and many cells die. For example, a model of axon injury, the optic nerve crush (ONC), kills ~80% of RGCs after two weeks. Surviving cells are biased towards ‘resilient’ types, including several with sustained firing to light stimulation. RGC survival may depend on activity, and there is limited understanding of how or why activity changes following optic nerve injury. Here we quantified the electrophysiological properties …

Inhibition Of Bmper Mitigates Pulmonary Hypertension By Modulating Lrp1-Yap Interaction In Smooth Muscle Cells, Hua Mao, Claire M Li, Bing Sun, Christopher S Ward, Alan R Waich-Cohen, Ivan O Rosas, Howard J Huang, Harry Karmouty-Quintana, Liang Xie, Lavannya M Pandit, Xinchun Pi

Faculty, Staff and Students Publications

Background: BMPER (bone morphogenetic protein-binding endothelial regulator) is a secreted protein that is highly expressed in endothelial cells. It regulates the BMP (bone morphogenetic protein) pathway during vascular development and adulthood. Mutations in the BMP pathway are recognized as risk factors for pulmonary arterial hypertension group 1 pulmonary hypertension (PH). However, the roles of BMPER in pulmonary arterial hypertension remain unknown.

Methods: We assessed BMPER expression in Group 1 pulmonary arterial hypertension patient samples and examined its role in vascular remodeling using in vivo and in vitro approaches.

Results: BMPER level was elevated in pulmonary arterial hypertension lungs and significantly …

Myeloid-Specific Camkk2 Deficiency Protects Against Diet-Induced Obesity And Insulin Resistance By Rewiring Metabolic Gene Expression And Enhancing Energy Expenditure, Andrea R Ortiz, Kevin Nay, Brittany A Stork, Adam M Dean, Sean M Hartig, Cristian Coarfa, Surafel Tegegne, Christopher Rm Asquith, Daniel E Frigo, Brian York, Anthony R Means, Mark A Febbraio, John W Scott

Faculty, Staff and Students Publications

Objective: Obesity is associated with chronic, low-grade inflammation in metabolic tissues such as liver, adipose tissue and skeletal muscle implicating insulin resistance and type 2 diabetes as inflammatory diseases. This inflammatory response involves the accumulation of pro-inflammatory macrophages in these metabolically relevant organs. The Ca2+-calmodulin-dependent protein kinase kinase-2 (CAMKK2) is a key regulator of cellular and systemic energy metabolism, and a coordinator of macrophage-mediated inflammatory responses. However, its role in obesity-associated metabolic dysfunction is not fully defined. The aim of this study was to determine the contribution of CAMKK2 to the regulation of inflammation and systemic metabolism during diet-induced obesity. …