Biochemistry, Biophysics, and Structural Biology Commons^™

Adeno-Associated Virus 8 Delivers An Immunomodulatory Peptide To Mouse Liver More Efficiently Than To Rat Liver, Yuqing Wang, Ayrea Hurley, Marco De Giorgi, Mark R Tanner, Rong-Chi Hu, Michael W Pennington, William R Lagor, Christine Beeton

Faculty, Staff and Students Publications

Targeting the Kv1.3 potassium channel has proven effective in reducing obesity and the severity of animal models of autoimmune disease. Stichodactyla toxin (ShK), isolated from the sea anemone Stichodactyla helianthus, is a potent blocker of Kv1.3. Several of its analogs are some of the most potent and selective blockers of this channel. However, like most biologics, ShK and its analogs require injections for their delivery, and repeated injections reduce patient compliance during the treatment of chronic diseases. We hypothesized that inducing the expression of an ShK analog by hepatocytes would remove the requirement for frequent injections and lead to a …

Optical Coherence Tomography For Dynamic Investigation Of Mammalian Reproductive Processes, Kohei Umezu, Irina V Larina

Faculty, Staff and Students Publications

The biological events associated with mammalian reproductive processes are highly dynamic and tightly regulated by molecular, genetic, and biomechanical factors. Implementation of live imaging in reproductive research is vital for the advancement of our understanding of normal reproductive physiology and for improving the management of reproductive disorders. Optical coherence tomography (OCT) is emerging as a promising tool for dynamic volumetric imaging of various reproductive processes in mice and other animal models. In this review, we summarize recent studies employing OCT-based approaches toward the investigation of reproductive processes in both, males and females. We describe how OCT can be applied to …

Tiam1-Mediated Synaptic Plasticity Underlies Comorbid Depression-Like And Ketamine Antidepressant-Like Actions In Chronic Pain, Qin Ru, Yungang Lu, Ali Bin Saifullah, Francisco A Blanco, Changqun Yao, Juan P Cata, De-Pei Li, Kimberley F Tolias, Lingyong Li

Faculty, Staff and Students Publications

Chronic pain often leads to depression, increasing patient suffering and worsening prognosis. While hyperactivity of the anterior cingulate cortex (ACC) appears to be critically involved, the molecular mechanisms underlying comorbid depressive symptoms in chronic pain remain elusive. T cell lymphoma invasion and metastasis 1 (Tiam1) is a Rac1 guanine nucleotide exchange factor (GEF) that promotes dendrite, spine, and synapse development during brain development. Here, we show that Tiam1 orchestrates synaptic structural and functional plasticity in ACC neurons via actin cytoskeleton reorganization and synaptic N-methyl-d-aspartate receptor (NMDAR) stabilization. This Tiam1-coordinated synaptic plasticity underpins ACC hyperactivity and drives chronic pain-induced depressive-like behaviors. …

An Elf4 Hypomorphic Variant Results In Nk Cell Deficiency, Sandra Andrea Salinas, Emily M Mace, Matilde I Conte, Chun Shik Park, Yu Li, Joshua I Rosario-Sepulveda, Sanjana Mahapatra, Emily K Moore, Evelyn R Hernandez, Ivan K Chinn, Abigail E Reed, Barclay J Lee, Alexander Frumovitz, Richard A Gibbs, Jennifer E Posey, Lisa R Forbes Satter, Akaluck Thatayatikom, Eric J Allenspach, Theodore G Wensel, James R Lupski, H Daniel Lacorazza, Jordan S Orange

Faculty, Staff and Students Publications

NK cell deficiencies (NKD) are a type of primary immune deficiency in which the major immunologic abnormality affects NK cell number, maturity, or function. Since NK cells contribute to immune defense against virally infected cells, patients with NKD experience higher susceptibility to chronic, recurrent, and fatal viral infections. An individual with recurrent viral infections and mild hypogammaglobulinemia was identified to have an X-linked damaging variant in the transcription factor gene ELF4. The variant does not decrease expression but disrupts ELF4 protein interactions and DNA binding, reducing transcriptional activation of target genes and selectively impairing ELF4 function. Corroborating previous murine models …

Clearance Of Hiv-1 Or Siv Reservoirs By Promotion Of Apoptosis And Inhibition Of Autophagy: Targeting Intracellular Molecules In Cure-Directed Strategies, Min Chen, Min Li, Marietta M Budai, Andrew P Rice, Jason T Kimata, Mahesh Mohan, Jin Wang

Faculty, Staff and Students Publications

The reservoirs of the HIV display cellular properties resembling long-lived immune memory cells that could be exploited for viral clearance. Our interest in developing a cure for HIV stems from the studies of immunologic memory against infections. We and others have found that long-lived immune memory cells employ prosurvival autophagy and antiapoptotic mechanisms to protect their longevity. Here, we describe the rationale for the development of an approach to clear HIV-1 by selective elimination of host cells harboring replication-competent HIV (SECH). While reactivation of HIV-1 in the host cells with latency reversing agents (LRAs) induces viral gene expression leading to …

Loss Of Non-Motor Kinesin Kif26a Causes Congenital Brain Malformations Via Dysregulated Neuronal Migration And Axonal Growth As Well As Apoptosis, Xuyu Qian, Ellen M Degennaro, Maya Talukdar, Shyam K Akula, Abbe Lai, Diane D Shao, Dilenny Gonzalez, Jack H Marciano, Richard S Smith, Norma K Hylton, Edward Yang, J Fernando Bazan, Lee Barrett, Rebecca C Yeh, R Sean Hill, Samantha G Beck, Aoi Otani, Jolly Angad, Tadahiro Mitani, Jennifer E Posey, Davut Pehlivan, Daniel Calame, Hatip Aydin, Osman Yesilbas, Kendall C Parks, Emanuela Argilli, Eleina England, Kiho Im, Ajay Taranath, Hamish S Scott, Christopher P Barnett, Peer Arts, Elliott H Sherr, James R Lupski, Christopher A Walsh

Faculty, Staff and Students Publications

Kinesins are canonical molecular motors but can also function as modulators of intracellular signaling. KIF26A, an unconventional kinesin that lacks motor activity, inhibits growth-factor-receptor-bound protein 2 (GRB2)- and focal adhesion kinase (FAK)-dependent signal transduction, but its functions in the brain have not been characterized. We report a patient cohort with biallelic loss-of-function variants in KIF26A, exhibiting a spectrum of congenital brain malformations. In the developing brain, KIF26A is preferentially expressed during early- and mid-gestation in excitatory neurons. Combining mice and human iPSC-derived organoid models, we discovered that loss of KIF26A causes excitatory neuron-specific defects in radial migration, localization, dendritic and …

Genetic Inhibition Of Nuclear Factor Of Activated T-Cell C2 Prevents Atrial Fibrillation In Crem Transgenic Mice, Li Ni, Satadru K Lahiri, Jiali Nie, Xiaolu Pan, Issam Abu-Taha, Julia O Reynolds, Hannah M Campbell, Haihao Wang, Markus Kamler, Wilhelm Schmitz, Frank Ulrich Müller, Na Li, Xiang Wei, Dao Wen Wang, Dobromir Dobrev, Xander H T Wehrens

Faculty, Staff and Students Publications

AIMS: Abnormal intracellular calcium (Ca2+) handling contributes to the progressive nature of atrial fibrillation (AF), the most common sustained cardiac arrhythmia. Evidence in mouse models suggests that activation of the nuclear factor of activated T-cell (NFAT) signalling pathway contributes to atrial remodelling. Our aim was to determine the role of NFATc2 in AF in humans and mouse models.

METHODS AND RESULTS: Expression levels of NFATc1-c4 isoforms were assessed by quantitative reverse transcription-polymerase chain reaction in right atrial appendages from patients with chronic AF (cAF). NFATc1 and NFATc2 mRNA levels were elevated in cAF patients compared with those in normal sinus …

Control Of Ribosomal Rna Synthesis By Hematopoietic Transcription Factors, Charles Antony, Subin S George, Justin Blum, Patrick Somers, Chelsea L Thorsheim, Dexter J Wu-Corts, Yuxi Ai, Long Gao, Kaosheng Lv, Michel G Tremblay, Tom Moss, Kai Tan, Jeremy E Wilusz, Austen R D Ganley, Maxim Pimkin, Vikram R Paralkar

Faculty, Staff and Students Publications

Ribosomal RNAs (rRNAs) are the most abundant cellular RNAs, and their synthesis from rDNA repeats by RNA polymerase I accounts for the bulk of all transcription. Despite substantial variation in rRNA transcription rates across cell types, little is known about cell-type-specific factors that bind rDNA and regulate rRNA transcription to meet tissue-specific needs. Using hematopoiesis as a model system, we mapped about 2,200 ChIP-seq datasets for 250 transcription factors (TFs) and chromatin proteins to human and mouse rDNA and identified robust binding of multiple TF families to canonical TF motifs on rDNA. Using a 47S-FISH-Flow assay developed for nascent rRNA …

Ez Clear For Simple, Rapid, And Robust Mouse Whole Organ Clearing, Chih-Wei Hsu, Juan Cerda, Jason M Kirk, Williamson D Turner, Tara L Rasmussen, Carlos P Flores Suarez, Mary E Dickinson, Joshua D Wythe

Faculty, Staff and Students Publications

Tissue clearing for whole organ cell profiling has revolutionized biology and imaging for exploration of organs in three-dimensional space without compromising tissue architecture. But complicated, laborious procedures, or expensive equipment, as well as the use of hazardous, organic solvents prevent the widespread adoption of these methods. Here, we report a simple and rapid tissue clearing method, EZ Clear, that can clear whole adult mouse organs in 48 hr in just three simple steps. Samples stay at room temperature and remain hydrated throughout the clearing process, preserving endogenous and synthetic fluorescence, without altering sample size. After wholemount clearing and imaging, samples …

Transmembrane Helices Mediate The Formation Of A Stable Ternary Complex Of B5r, Cyt B5, And Scd1, Jiemin Shen, Gang Wu, Ah-Lim Tsai, Ming Zhou

Faculty, Staff and Students Publications

Mammalian cytochrome b5 (cyt b5) and cytochrome b5 reductase (b5R) are electron carrier proteins for membrane-embedded oxidoreductases. Both b5R and cyt b5 have a cytosolic domain and a single transmembrane (TM) helix. The cytosolic domains of b5R and cyt b5 contain cofactors required for electron transfer, but it is not clear if the TM helix has function beyond being an anchor to the membrane. Here we show that b5R and cyt b5 form a stable binary complex, and so do cyt b5 and stearoyl-CoA desaturase-1 (SCD1). We also show that b5R, cyt b5 and SCD1 form a stable ternary complex. …

A Potential Role For Substance P In West Nile Virus Neuropathogenesis, Shannon E Ronca, Sarah M Gunter, Rebecca Berry Kairis, Allison Lino, Jonathan Romero, Robia G Pautler, Alan Nimmo, Kristy O Murray

Faculty, Staff and Students Publications

Of individuals who develop West Nile neuroinvasive disease (WNND), ~10% will die and >40% will develop long-term complications. Current treatment recommendations solely focus on supportive care; therefore, we urgently need to identify novel and effective therapeutic options. We observed a correlation between substance P (SP), a key player in neuroinflammation, and its receptor Neurokinin-1 (NK1R). Our study in a wild-type BL6 mouse model found that SP is upregulated in the brain during infection, which correlated with neuroinvasion and damage to the blood−brain barrier. Blocking the SP/NK1R interaction beginning at disease onset modestly improved survival and prolonged time to death in …

The Emerging Spectrum Of Cardiopulmonary Pathology Of The Coronavirus Disease 2019 (Covid-19): Report Of 3 Autopsies From Houston, Texas, And Review Of Autopsy Findings From Other United States Cities, Manish Bodas, Bharathiraja Subramaniyan, Harry Karmouty-Quintana, Peter F Vitiello, Matthew S Walters

Faculty, Staff and Student Publications

The mammalian respiratory system or lung is a tree-like branching structure, and the main site of gas exchange with the external environment. Structurally, the lung is broadly classified into the proximal (or conducting) airways and the distal alveolar region, where the gas exchange occurs. In parallel with the respiratory tree, the pulmonary vasculature starts with large pulmonary arteries that subdivide rapidly ending in capillaries adjacent to alveolar structures to enable gas exchange. The NOTCH signalling pathway plays an important role in lung development, differentiation and regeneration post-injury. Signalling via the NOTCH pathway is mediated through activation of four NOTCH receptors …

Sustained Deep-Tissue Voltage Recording Using A Fast Indicator Evolved For Two-Photon Microscopy, Zhuohe Liu, Xiaoyu Lu, Vincent Villette, Yueyang Gou, Kevin L Colbert, Shujuan Lai, Sihui Guan, Michelle A Land, Jihwan Lee, Tensae Assefa, Daniel R Zollinger, Maria M Korympidou, Anna L Vlasits, Michelle M Pang, Sharon Su, Changjia Cai, Emmanouil Froudarakis, Na Zhou, Saumil S Patel, Cameron L Smith, Annick Ayon, Pierre Bizouard, Jonathan Bradley, Katrin Franke, Thomas R Clandinin, Andrea Giovannucci, Andreas S Tolias, Jacob Reimer, Stéphane Dieudonné, François St-Pierre

Faculty, Staff and Students Publications

Genetically encoded voltage indicators are emerging tools for monitoring voltage dynamics with cell-type specificity. However, current indicators enable a narrow range of applications due to poor performance under two-photon microscopy, a method of choice for deep-tissue recording. To improve indicators, we developed a multiparameter high-throughput platform to optimize voltage indicators for two-photon microscopy. Using this system, we identified JEDI-2P, an indicator that is faster, brighter, and more sensitive and photostable than its predecessors. We demonstrate that JEDI-2P can report light-evoked responses in axonal termini of Drosophila interneurons and the dendrites and somata of amacrine cells of isolated mouse retina. JEDI-2P …

A Mouse Holder For Awake Functional Imaging In Unanesthetized Mice: Applications In 31p Spectroscopy, Manganese-Enhanced Magnetic Resonance Imaging Studies, And Resting-State Functional Magnetic Resonance Imaging, Lindsay C Fadel, Ivany V Patel, Jonathan Romero, I-Chih Tan, Shelli R Kesler, Vikram Rao, S A Amali S Subasinghe, Russell S Ray, Jason T Yustein, Matthew J Allen, Brian W Gibson, Justin J Verlinden, Stanley Fayn, Nicole Ruggiero, Caitlyn Ortiz, Elizabeth Hipskind, Aaron Feng, Chijindu Iheanacho, Alex Wang, Robia G Pautler

Faculty, Staff and Students Publications

Anesthesia is often used in preclinical imaging studies that incorporate mouse or rat models. However, multiple reports indicate that anesthesia has significant physiological impacts. Thus, there has been great interest in performing imaging studies in awake, unanesthetized animals to obtain accurate results without the confounding physiological effects of anesthesia. Here, we describe a newly designed mouse holder that is interfaceable with existing MRI systems and enables awake in vivo mouse imaging. This holder significantly reduces head movement of the awake animal compared to previously designed holders and allows for the acquisition of improved anatomical images. In addition to applications in …

Sex-Specific Phenotypes In The Aging Mouse Heart And Consequences For Chronic Fibrosis, Aude Angelini, Jesus Ortiz-Urbina, Joann Trial, Anilkumar K Reddy, Anna Malovannaya, Antrix Jain, Mark L Entman, George E Taffet, Katarzyna A Cieslik

Faculty, Staff and Students Publications

The incidence of diastolic dysfunction increases with age in both humans and mice. This is characterized by increased passive stiffness and slower relaxation of the left ventricle. The stiffness arises at least partially from progressively increased interstitial collagen deposition because of highly secretory fibroblasts. In the past, we demonstrated that AMPK activation via the drug 5-aminoimidazole-4-carboxamide riboside (AICAR) in middle-aged mice reduced adverse remodeling after myocardial infarction. Therefore, as an attempt to normalize the fibroblast phenotype, we used 21-mo-old male and female mice and treated them with AICAR (0.166 mg/g body wt) where each mouse was followed in a functional …

Extracellular Domain Of Pept1 Interacts With Tm1 To Facilitate Substrate Transport, Jiemin Shen, Miaohui Hu, Xiao Fan, Zhenning Ren, Corinne Portioli, Xiuwen Yan, Mingqiang Rong, Ming Zhou

Faculty, Staff and Students Publications

Mammalian peptide transporters, PepT1 and PepT2, mediate uptake of small peptides and are essential for their absorption. PepT also mediates absorption of many drugs and prodrugs to enhance their bioavailability. PepT has twelve transmembrane (TM) helices that fold into an N-terminal domain (NTD, TM1–6) and a C-terminal domain (CTD, TM7–12), and has a large extracellular domain (ECD) between TM9–10. It is well-recognized that peptide transport requires movements of the NTD and CTD, but the role of the ECD in PepT1 remains unclear. Here we report the structure of horse PepT1 encircled in lipid nanodiscs and captured in the inward-open apo …

Crispr/Cas13 Effectors Have Differing Extents Of Off-Target Effects That Limit Their Utility In Eukaryotic Cells, Yuxi Ai, Dongming Liang, Jeremy E Wilusz

Faculty, Staff and Students Publications

CRISPR/Cas13 effectors have garnered increasing attention as easily customizable tools for detecting and depleting RNAs of interest. Near perfect complementarity between a target RNA and the Cas13-associated guide RNA is required for activation of Cas13 ribonuclease activity. Nonetheless, the specificity of Cas13 effectors in eukaryotic cells has been debated as the Cas13 nuclease domains can be exposed on the enzyme surface, providing the potential for promiscuous cleavage of nearby RNAs (so-called collateral damage). Here, using co-transfection assays in Drosophila and human cells, we found that the off-target effects of RxCas13d, a commonly used Cas13 effector, can be as strong as …

Variants In Asph Cause Exertional Heat Illness And Are Associated With Malignant Hyperthermia Susceptibility, Yukari Endo, Linda Groom, Alper Celik, Natalia Kraeva, Chang Seok Lee, Sung Yun Jung, Lois Gardner, Marie-Anne Shaw, Susan L Hamilton, Philip M Hopkins, Robert T Dirksen, Sheila Riazi, James J Dowling

Faculty, Staff and Students Publications

Exertional heat illness (EHI) and malignant hyperthermia (MH) are life threatening conditions associated with muscle breakdown in the setting of triggering factors including volatile anesthetics, exercise, and high environmental temperature. To identify new genetic variants that predispose to EHI and/or MH, we performed genomic sequencing on a cohort with EHI/MH and/or abnormal caffeine-halothane contracture test. In five individuals, we identified rare, pathogenic heterozygous variants in ASPH, a gene encoding junctin, a regulator of excitation-contraction coupling. We validated the pathogenicity of these variants using orthogonal pre-clinical models, CRISPR-edited C2C12 myotubes and transgenic zebrafish. In total, we demonstrate that ASPH variants represent …

A Novel Crosstalk Between Autophagosomes And Phagosomes That Facilitates The Clearance Of Apoptotic Cells, Zheng Zhou, Omar Peña-Ramos

Faculty, Staff and Students Publications

During an animal's life, many cells undergo apoptosis, a form of genetically programmed cell death. These cells are swiftly engulfed by other cells through phagocytosis and subsequently degraded inside phagosomes. Phagocytosis and macroautophagy/autophagy are two different cellular events: whereas phagocytosis is a cell-eat-cell event, autophagy, or "self-eating", occurs within one cell, resulting in the enveloping of protein aggregates or damaged organelles within double-membrane autophagosomes. Despite this critical difference, these two events share common features: (1) both are means of safe garbage disposal; (2) both phagosomes and autophagosomes fuse to lysosomes, which drive the degradation of their contents; and (3) both …

Maf1, A Repressor Of Rna Polymerase Iii-Dependent Transcription, Regulates Bone Mass, Ellen Phillips, Naseer Ahmad, Li Sun, James Iben, Christopher J Walkey, Aleksandra Rusin, Tony Yuen, Clifford J Rosen, Ian M Willis, Mone Zaidi, Deborah L Johnson

Faculty, Staff and Students Publications

MAF1, a key repressor of RNA polymerase (pol) III-mediated transcription, has been shown to promote mesoderm formation in vitro. Here, we show that MAF1 plays a critical role in regulating osteoblast differentiation and bone mass. Global deletion of MAF1 (Maf1-/- mice) produced a high bone mass phenotype. However, osteoblasts isolated from Maf1-/- mice showed reduced osteoblastogenesis ex vivo. Therefore, we determined the phenotype of mice overexpressing MAF1 in cells from the mesenchymal lineage (Prx1-Cre;LSL-MAF1 mice). These mice showed increased bone mass. Ex vivo, cells from these mice showed enhanced osteoblastogenesis concordant with their high …

Targeting Aberrant Replication And Dna Repair Events For Treating Breast Cancers, Subapriya Rajamanickam, Jun Hyoung Park, Panneerdoss Subbarayalu, Santosh Timilsina, Kaitlyn Bates, Pooja Yadav, Saif S R Nirzhor, Vijay Eedunuri, Tabrez A Mohammad, Kwang Hwa Jung, Benjamin Onyeagucha, Nourhan Abdelfattah, Raymond Benevides, Grace Lee, Yidong Chen, Ratna Vadlamudi, Andrew Brenner, Virginia Kaklamani, Ismail Jatoi, John Kuhn, Robert Hromas, Yogesh K Gupta, Benny A Kaipparettu, Jack L Arbiser, Manjeet K Rao

Faculty, Staff and Students Publications

The major limitations of DNA-targeting chemotherapy drugs include life-threatening toxicity, acquired resistance and occurrence of secondary cancers. Here, we report a small molecule, Carbazole Blue (CB), that binds to DNA and inhibits cancer growth and metastasis by targeting DNA-related processes that tumor cells use but not the normal cells. We show that CB inhibits the expression of pro-tumorigenic genes that promote unchecked replication and aberrant DNA repair that cancer cells get addicted to survive. In contrast to chemotherapy drugs, systemic delivery of CB suppressed breast cancer growth and metastasis with no toxicity in pre-clinical mouse models. Using PDX and ex …

Alterations Of The Gut Microbial Community Structure And Function With Aging In The Spontaneously Hypertensive Stroke Prone Rat, Huanan Shi, James W Nelson, Sharon Phillips, Joseph F Petrosino, Robert M Bryan, David J Durgan

Faculty, Staff and Students Publications

Gut dysbiosis, a pathological imbalance of bacteria, has been shown to contribute to the development of hypertension (HT), systemic- and neuro-inflammation, and blood-brain barrier (BBB) disruption in spontaneously hypertensive stroke prone rats (SHRSP). However, to date individual species that contribute to HT in the SHRSP model have not been identified. One potential reason, is that nearly all studies of the SHRSP gut microbiota have analyzed samples from rats with established HT. The goal of this study was to examine the SHRSP gut microbiota before, during, and after the onset of hypertension, and in normotensive WKY control rats over the same …

Spata7 Is Required For Maintenance Of The Retinal Connecting Cilium, Jiaxiong Lu, Kaitlyn Xiong, Xinye Qian, Jongsu Choi, Yoon-Kyung Shim, Jacob Burnett, Graeme Mardon, Rui Chen

Faculty, Staff and Students Publications

SPATA7, an early onset LCA3 retinal disease gene, encodes a putative scaffold protein that is essential for the proper assembly of the connecting cilium (CC) complex in photoreceptors. Previous studies have shown that SPATA7 interacts with other photoreceptor-specific ciliary proteins, such as RPGR and RPGRIP1, and maintains the integrity of CC integrity. However, although it is known that Spata7 is required for early formation of the CC, it is unclear if Spata7 is also required for the maintenance of the CC. To investigate Spata7 function in the retina at the adult stage, loss of function was induced in the …

Foxo1 Represses Sprouty 2 And Sprouty 4 Expression To Promote Arterial Specification And Vascular Remodeling In The Mouse Yolk Sac, Nanbing Li-Villarreal, Rebecca Lee Yean Wong, Monica D Garcia, Ryan S Udan, Ross A Poché, Tara L Rasmussen, Alexander M Rhyner, Joshua D Wythe, Mary E Dickinson

Faculty, Staff and Students Publications

Establishing a functional circulatory system is required for post-implantation development during murine embryogenesis. Previous studies in loss-of-function mouse models showed that FOXO1, a Forkhead family transcription factor, is required for yolk sac (YS) vascular remodeling and survival beyond embryonic day (E) 11. Here, we demonstrate that at E8.25, loss of Foxo1 in Tie2-cre expressing cells resulted in increased sprouty 2 (Spry2) and Spry4 expression, reduced arterial gene expression and reduced Kdr (also known as Vegfr2 and Flk1) transcripts without affecting overall endothelial cell identity, survival or proliferation. Using a Dll4-BAC-nlacZ reporter line, we found that one of the earliest expressed …

Intestinal Deletion Of 3-Hydroxy-3-Methylglutaryl-Coenzyme A Reductase Promotes Expansion Of The Resident Stem Cell Compartment, Alexandria M Doerfler, Jun Han, Kelsey E Jarrett, Li Tang, Antrix Jain, Alexander Saltzman, Marco De Giorgi, Marcel Chuecos, Ayrea E Hurley, Ang Li, Pauline Morand, Claudia Ayala, David R Goodlett, Anna Malovannaya, James F Martin, Thomas Q De Aguiar Vallim, Noah Shroyer, William R Lagor

Faculty, Staff and Students Publications

BACKGROUND: The intestine occupies the critical interface between cholesterol absorption and excretion. Surprisingly little is known about the role of de novo cholesterol synthesis in this organ, and its relationship to whole body cholesterol homeostasis. Here, we investigate the physiological importance of this pathway through genetic deletion of the rate-limiting enzyme.

METHODS: Mice lacking 3-hydroxy-3-methylglutaryl-coenzyme A reductase (Hmgcr) in intestinal villus and crypt epithelial cells were generated using a Villin-Cre transgene. Plasma lipids, intestinal morphology, mevalonate pathway metabolites, and gene expression were analyzed.

RESULTS: Mice with intestine-specific loss of Hmgcr were markedly smaller at birth, but gain …

Oleic Acid Is An Endogenous Ligand Of Tlx/Nr2e1 That Triggers Hippocampal Neurogenesis, Prasanna Kandel, Fatih Semerci, Rachana Mishra, William Choi, Aleksandar Bajic, Dodge Baluya, Lihua Ma, Kevin Chen, Austin C Cao, Tipwarin Phongmekhin, Nick Matinyan, Alba Jiménez-Panizo, Srinivas Chamakuri, Idris O Raji, Lyra Chang, Pablo Fuentes-Prior, Kevin R Mackenzie, Caroline L Benn, Eva Estébanez-Perpiñá, Koen Venken, David D Moore, Damian W Young, Mirjana Maletic-Savatic

Faculty, Staff and Students Publications

Neural stem cells, the source of newborn neurons in the adult hippocampus, are intimately involved in learning and memory, mood, and stress response. Despite considerable progress in understanding the biology of neural stem cells and neurogenesis, regulating the neural stem cell population precisely has remained elusive because we have lacked the specific targets to stimulate their proliferation and neurogenesis. The orphan nuclear receptor TLX/NR2E1 governs neural stem and progenitor cell self-renewal and proliferation, but the precise mechanism by which it accomplishes this is not well understood because its endogenous ligand is not known. Here, we identify oleic acid (18:1ω9 monounsaturated …

Depletion Of Transmembrane Mucin 4 (Muc4) Alters Intestinal Homeostasis In A Genetically Engineered Mouse Model Of Colorectal Cancer, Ramesh Pothuraju, Priya Pai, Sanjib Chaudhary, Jawed A Siddiqui, Jesse L Cox, Sukhwinder Kaur, Satyanarayana Rachagani, Hemant K Roy, Michael Bouvet, Surinder K Batra

Faculty, Staff and Students Publications

Mucins are components of the mucus layer overlying the intestinal epithelial cells, which maintains physiological homeostasis. Altered mucin expression is associated with disease progression. Expression of MUC4 decreases in colorectal cancer (CRC); however, its functional role and implications in the intestinal pathology in CRC are not studied well. Therefore, we generated a genetically engineered Muc4 knockout (Muc4-/-) CRC mouse model by crossing with Muc4-/- and Apc^flox/flox mice in the presence of colon-specific inducible Cre. We observed that deficiency of Muc4 results in an increased number of macroscopic tumors in the colon and rectal region and leads to poor survival. …

Syndecan-2 Regulates Pad2 To Exert Antifibrotic Effects On Ra-Ild Fibroblasts, Konstantin Tsoyi, Anthony J Esposito, Bo Sun, Ryan G Bowen, Kevin Xiong, Fernando Poli, Rafael Cardenas, Sarah G Chu, Xiaoliang Liang, Stefan W Ryter, Christine Beeton, Tracy J Doyle, Matthew J Robertson, Lindsay J Celada, Freddy Romero, Souheil Y El-Chemaly, Mark A Perrella, I-Cheng Ho, Ivan O Rosas

Faculty, Staff and Students Publications

Rheumatoid arthritis (RA)-associated interstitial lung disease (RA-ILD) is the most common pulmonary complication of RA, increasing morbidity and mortality. Anti-citrullinated protein antibodies have been associated with the development and progression of both RA and fibrotic lung disease; however, the role of protein citrullination in RA-ILD remains unclear. Here, we demonstrate that the expression of peptidylarginine deiminase 2 (PAD2), an enzyme that catalyzes protein citrullination, is increased in lung homogenates from subjects with RA-ILD and their lung fibroblasts. Chemical inhibition or genetic knockdown of PAD2 in RA-ILD fibroblasts attenuated their activation, marked by decreased myofibroblast differentiation, gel contraction, and extracellular matrix …

Retinal Horizontal Cells Use Different Synaptic Sites For Global Feedforward And Local Feedback Signaling, Christian Behrens, Shubhash Chandra Yadav, Maria M Korympidou, Yue Zhang, Silke Haverkamp, Stephan Irsen, Anna Schaedler, Xiaoyu Lu, Zhuohe Liu, Jan Lause, François St-Pierre, Katrin Franke, Anna Vlasits, Karin Dedek, Robert G Smith, Thomas Euler, Philipp Berens, Timm Schubert

Faculty, Staff and Students Publications

In the outer plexiform layer (OPL) of the mammalian retina, cone photoreceptors (cones) provide input to more than a dozen types of cone bipolar cells (CBCs). In the mouse, this transmission is modulated by a single horizontal cell (HC) type. HCs perform global signaling within their laterally coupled network but also provide local, cone-specific feedback. However, it is unknown how HCs provide local feedback to cones at the same time as global forward signaling to CBCs and where the underlying synapses are located. To assess how HCs simultaneously perform different modes of signaling, we reconstructed the dendritic trees of five …

A Crispr Toolbox For Generating Intersectional Genetic Mouse Models For Functional, Molecular, And Anatomical Circuit Mapping, Savannah J Lusk, Andrew Mckinney, Patrick J Hunt, Paul G Fahey, Jay Patel, Andersen Chang, Jenny J Sun, Vena K Martinez, Ping Jun Zhu, Jeremy R Egbert, Genevera Allen, Xiaolong Jiang, Benjamin R Arenkiel, Andreas S Tolias, Mauro Costa-Mattioli, Russell S Ray

Faculty, Staff and Students Publications

BACKGROUND: The functional understanding of genetic interaction networks and cellular mechanisms governing health and disease requires the dissection, and multifaceted study, of discrete cell subtypes in developing and adult animal models. Recombinase-driven expression of transgenic effector alleles represents a significant and powerful approach to delineate cell populations for functional, molecular, and anatomical studies. In addition to single recombinase systems, the expression of two recombinases in distinct, but partially overlapping, populations allows for more defined target expression. Although the application of this method is becoming increasingly popular, its experimental implementation has been broadly restricted to manipulations of a limited set of …