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Rong S, Yu X, Wiggs JL. Genetic Basis of Pigment Dispersion Syndrome and Pigmentary Glaucoma: An Update and Functional Insights. Genes (Basel) 2024; 15:142. [PMID: 38397132 PMCID: PMC10887877 DOI: 10.3390/genes15020142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 01/16/2024] [Accepted: 01/18/2024] [Indexed: 02/25/2024] Open
Abstract
Pigment Dispersion Syndrome (PDS) and Pigmentary Glaucoma (PG) comprise a spectrum of ocular disorders characterized by iris pigment dispersion and trabecular meshwork changes, resulting in increased intraocular pressure and potential glaucomatous optic neuropathy. This review summarizes recent progress in PDS/PG genetics including rare pathogenic protein coding alterations (PMEL) and susceptibility loci identified from genome-wide association studies (GSAP and GRM5/TYR). Areas for future research are also identified, especially the development of efficient model systems. While substantial strides have been made in understanding the genetics of PDS/PG, our review identifies key gaps and outlines the future directions necessary for further advancing this important field of ocular genetics.
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Affiliation(s)
- Shisong Rong
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear, Mass General Brigham, Harvard Medical School, Boston, MA 02114, USA;
| | - Xinting Yu
- Department of Medicine, Brigham and Women’s Hospital, Mass General Brigham, Harvard Medical School, Boston, MA 02115, USA;
| | - Janey L. Wiggs
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear, Mass General Brigham, Harvard Medical School, Boston, MA 02114, USA;
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
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Gu Q, Kumar A, Hook M, Xu F, Bajpai AK, Starlard-Davenport A, Yue J, Jablonski MM, Lu L. Exploring Early-Stage Retinal Neurodegeneration in Murine Pigmentary Glaucoma: Insights From Gene Networks and miRNA Regulation Analyses. Invest Ophthalmol Vis Sci 2023; 64:25. [PMID: 37707836 PMCID: PMC10506683 DOI: 10.1167/iovs.64.12.25] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 06/26/2023] [Indexed: 09/15/2023] Open
Abstract
Purpose Glaucoma is a group of heterogeneous optic neuropathies characterized by the progressive degeneration of retinal ganglion cells. However, the underlying mechanisms have not been understood completely. We aimed to elucidate the genetic network associated with the development of pigmentary glaucoma with DBA/2J (D2) mouse model of glaucoma and corresponding genetic control D2-Gpnmb (D2G) mice carrying the wild type (WT) Gpnmb allele. Methods Retinas isolated from 13 D2 and 12 D2G mice were subdivided into 2 age groups: pre-onset (1-6 months: samples were collected at approximately 1-2, 2-4, and 5-6 months) and post-onset (7-15 months: samples were collected at approximately 7-9, 10-12, and 13-15 months) glaucoma were compared. Differential gene expression (DEG) analysis and gene-set enrichment analyses were performed. To identify micro-RNAs (miRNAs) that target Gpnmb, miRNA expression levels were correlated with time point matched mRNA expression levels. A weighted gene co-expression network analysis (WGCNA) was performed using the reference BXD mouse population. Quantitative real-time PCR (qRT-PCR) was used to validate Gpnmb and miRNA expression levels. Results A total of 314 and 86 DEGs were identified in the pre-onset and post-onset glaucoma groups, respectively. DEGs in the pre-onset glaucoma group were associated with the crystallin gene family, whereas those in the post-onset group were related to innate immune system response. Of 1329 miRNAs predicted to target Gpnmb, 3 miRNAs (miR-125a-3p, miR-3076-5p, and miR-214-5p) were selected. A total of 47 genes demonstrated overlapping with the identified DEGs between D2 and D2G, segregated into their time-relevant stages. Gpnmb was significantly downregulated, whereas 2 out of 3 miRNAs were significantly upregulated (P < 0.05) in D2 mice at both 3-and 10-month time points. Conclusions These findings suggest distinct gene-sets involved in pre-and post-glaucoma in the D2 mouse. We identified three miRNAs regulating Gpnmb in the development of murine pigmentary glaucoma.
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Affiliation(s)
- Qingqing Gu
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, Tennessee, United States
- Department of Cardiology, Affiliated Hospital of Nantong University, Jiangsu, China
| | - Aman Kumar
- Department of Ophthalmology, Hamilton Eye Institute, University of Tennessee Health Science Center, Memphis, Tennessee, United States
| | - Michael Hook
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, Tennessee, United States
| | - Fuyi Xu
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, Tennessee, United States
- Shandong Technology Innovation Center of Molecular Targeting and Intelligent Diagnosis and Treatment, School of Pharmacy, Binzhou Medical University, Yantai, Shandong, China
| | - Akhilesh Kumar Bajpai
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, Tennessee, United States
| | - Athena Starlard-Davenport
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, Tennessee, United States
| | - Junming Yue
- Department of Pathology, University of Tennessee Health Science Center, Memphis, Tennessee, United States
| | - Monica M. Jablonski
- Department of Ophthalmology, Hamilton Eye Institute, University of Tennessee Health Science Center, Memphis, Tennessee, United States
| | - Lu Lu
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, Tennessee, United States
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3
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Ashbrook DG, Arends D, Prins P, Mulligan MK, Roy S, Williams EG, Lutz CM, Valenzuela A, Bohl CJ, Ingels JF, McCarty MS, Centeno AG, Hager R, Auwerx J, Lu L, Williams RW. A platform for experimental precision medicine: The extended BXD mouse family. Cell Syst 2021; 12:235-247.e9. [PMID: 33472028 PMCID: PMC7979527 DOI: 10.1016/j.cels.2020.12.002] [Citation(s) in RCA: 89] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/29/2020] [Accepted: 12/21/2020] [Indexed: 12/17/2022]
Abstract
The challenge of precision medicine is to model complex interactions among DNA variants, phenotypes, development, environments, and treatments. We address this challenge by expanding the BXD family of mice to 140 fully isogenic strains, creating a uniquely powerful model for precision medicine. This family segregates for 6 million common DNA variants-a level that exceeds many human populations. Because each member can be replicated, heritable traits can be mapped with high power and precision. Current BXD phenomes are unsurpassed in coverage and include much omics data and thousands of quantitative traits. BXDs can be extended by a single-generation cross to as many as 19,460 isogenic F1 progeny, and this extended BXD family is an effective platform for testing causal modeling and for predictive validation. BXDs are a unique core resource for the field of experimental precision medicine.
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Affiliation(s)
- David G Ashbrook
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN 38163, USA.
| | - Danny Arends
- Lebenswissenschaftliche Fakultät, Albrecht Daniel Thaer-Institut, Humboldt-Universität zu Berlin, Invalidenstraße 42, 10115 Berlin, Germany
| | - Pjotr Prins
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Megan K Mulligan
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Suheeta Roy
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Evan G Williams
- Luxembourg Centre for Systems Biomedicine, Université du Luxembourg, L-4365 Esch-sur-Alzette, Luxembourg
| | - Cathleen M Lutz
- Mouse Repository and the Rare and Orphan Disease Center, the Jackson Laboratory, Bar Harbor, ME 04609, USA
| | - Alicia Valenzuela
- Mouse Repository and the Rare and Orphan Disease Center, the Jackson Laboratory, Bar Harbor, ME 04609, USA
| | - Casey J Bohl
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Jesse F Ingels
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Melinda S McCarty
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Arthur G Centeno
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Reinmar Hager
- Division of Evolution & Genomic Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Johan Auwerx
- Laboratory of Integrative Systems Physiology, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Lu Lu
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN 38163, USA.
| | - Robert W Williams
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN 38163, USA.
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Stiemke AB, Sah E, Simpson RN, Lu L, Williams RW, Jablonski MM. Systems Genetics of Optic Nerve Axon Necrosis During Glaucoma. Front Genet 2020; 11:31. [PMID: 32174956 PMCID: PMC7056908 DOI: 10.3389/fgene.2020.00031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 01/09/2020] [Indexed: 12/28/2022] Open
Abstract
In this study, we identify genomic regions that modulate the number of necrotic axons in optic nerves of a family of mice, some of which have severe glaucoma, and define a set of high priority positional candidate genes that modulate retinal ganglion cell (RGC) axonal degeneration. A large cohort of the BXD family were aged to greater than 13 months of age. Optic nerves from 74 strains and the DBA/2J (D2) parent were harvested, sectioned, and stained with p-phenylenediamine. Numbers of necrotic axons per optic nerve cross-section were counted from 1 to 10 replicates per genotype. Strain means and standard errors were uploaded into GeneNetwork 2 for mapping and systems genetics analyses (Trait 18614). The number of necrotic axons per nerve ranged from only a few hundred to more than 4,000. Using conventional interval mapping as well as linear mixed model mapping, we identified a single locus on chromosome 12 between 109 and 112.5 Mb with a likelihood ratio statistic (LRS) of ~18.5 (p genome-wide ~0.1). Axon necrosis is not linked to locations of major known glaucoma genes in this family, including Gpnmb, Tyrp1, Cdh11, Pou6f2, and Cacna2d1. This indicates that although these genes contribute to pigmentary dispersion or elevated IOP, none directly modulates axon necrosis. Of 156 positional candidates, eight genes—CDC42 binding protein kinase beta (Cdc42bpb); eukaryotic translation initiation factor 5 (Eif5); BCL2-associated athanogene 5 (Bag5); apoptogenic 1, mitochondrial (Apopt1); kinesin light chain 1 (Klc1); X-ray repair cross complementing 3 (Xrcc3); protein phosphatase 1, regulatory subunit 13B (Ppp1r13b); and transmembrane protein 179 (Tmem179)—passed stringent criteria and are high priority candidates. Several candidates are linked to mitochondria and/or axons, strengthening their plausible role as modulators of ON necrosis. Additional studies are required to validate and/or eliminate plausible candidates. Surprisingly, IOP and ON necrosis are inversely correlated across the BXD family in mice >13 months of age and these two traits share few genes among their top ocular and retinal correlates. These data suggest that the two traits are independently modulated or that a more complex and multifaceted approach is required to reveal their association.
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Affiliation(s)
- Andrew B Stiemke
- Department of Genetics, Genomics and Informatics, The University of Tennessee Health Science Center, Memphis, TN, United States
| | - Eric Sah
- Department of Ophthalmology, The Hamilton Eye Institute, The University of Tennessee Health Science Center, Memphis, TN, United States
| | - Raven N Simpson
- Department of Ophthalmology, The Hamilton Eye Institute, The University of Tennessee Health Science Center, Memphis, TN, United States
| | - Lu Lu
- Department of Genetics, Genomics and Informatics, The University of Tennessee Health Science Center, Memphis, TN, United States
| | - Robert W Williams
- Department of Genetics, Genomics and Informatics, The University of Tennessee Health Science Center, Memphis, TN, United States.,Department of Ophthalmology, The Hamilton Eye Institute, The University of Tennessee Health Science Center, Memphis, TN, United States
| | - Monica M Jablonski
- Department of Ophthalmology, The Hamilton Eye Institute, The University of Tennessee Health Science Center, Memphis, TN, United States
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Zhang Y, Xu Y, Sun Q, Xue S, Guan H, Ji M. Activation of P2X7R- NLRP3 pathway in Retinal microglia contribute to Retinal Ganglion Cells death in chronic ocular hypertension (COH). Exp Eye Res 2019; 188:107771. [DOI: 10.1016/j.exer.2019.107771] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 07/25/2019] [Accepted: 08/19/2019] [Indexed: 12/15/2022]
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Lu Y, Zhou D, Lu H, Xu F, Yue J, Tong J, Lu L. Investigating a downstream gene of Gpnmb using the systems genetics method. Mol Vis 2019; 25:222-236. [PMID: 31057322 PMCID: PMC6478243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 04/21/2019] [Indexed: 11/01/2022] Open
Abstract
Purpose Glaucoma is characterized by optic nerve damage and retinal ganglion cell loss. The glycoprotein neuromedin B-associated (Gpnmb) gene is well-known to be involved in the glaucoma disease process. The purpose of this study is to identify a downstream gene through which Gpnmb affects the glaucoma phenotypes using a systems genetics approach. Methods Retinal gene expression data for the BXD recombinant inbred (RI) strains (n=75) have previously been generated in our laboratory for a glaucoma study, and these data were used for genetic and bioinformatics analysis. Expression quantitative trait locus (eQTL) mapping and genetic correlation methods were used to identify a gene downstream of Gpnmb. Gene-set enrichment analysis was used to evaluate gene function and to construct coexpression networks. Results The level of Gpnmb expression is associated with a highly statistically significant cis-eQTL. Stanniocalcin 1 (Stc1) has a significant trans-eQTL mapping to the Gpnmb locus. The expression of Gpnmb and Stc1 is highly correlated in the retina and other tissues, as well as with glaucoma-related phenotypes. Gene Ontology and pathway analysis showed that Stc1 and its covariates are highly associated with apoptosis, oxidative stress, and mitochondrial activity. A generated gene network indicated that Gpnmb and Stc1 are directly connected to and interact with other genes with similar biologic functions. Conclusions These results suggest that Stc1 may be a downstream candidate of Gpnmb, and that both genes interact with other genes in a network to develop glaucoma pathogenesis through mechanisms such as apoptosis and oxidative stress.
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Affiliation(s)
- Ye Lu
- Department of Ophthalmology, The First Affiliated Hospital, Zhejiang University College of Medicine, Hangzhou, China
| | - Diana Zhou
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN
| | - Hong Lu
- Department of Ophthalmology, Nantong Eye Institute, Affiliated Hospital of Nantong University, Nantong, China
| | - Fuyi Xu
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN
| | - Junming Yue
- Department of Pathology, University of Tennessee Health Science Center, Memphis, TN
| | - Jianping Tong
- Department of Ophthalmology, The First Affiliated Hospital, Zhejiang University College of Medicine, Hangzhou, China
| | - Lu Lu
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN
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7
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Lu Y, Zhou D, King R, Zhu S, Simpson CL, Jones BC, Zhang W, Geisert EE, Lu L. The genetic dissection of Myo7a gene expression in the retinas of BXD mice. Mol Vis 2018; 24:115-126. [PMID: 29430167 PMCID: PMC5802760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 01/31/2018] [Indexed: 11/16/2022] Open
Abstract
Purpose Usher syndrome (US) is characterized by a loss of vision due to retinitis pigmentosa (RP) and deafness. US has three clinical subtypes, but even within each subtype, the severity varies. Myosin VIIA, coded by Myo7a, has been identified as one of the causal genes of US. This study aims to identify pathways and other genes through which Myo7a interacts to affect the presentation of US symptoms. Methods In this study, we used the retinal tissue of BXD recombinant inbred (RI) mice to examine the expression of Myo7a and perform genetic mapping. Expression quantitative trait locus (eQTL), single nucleotide polymorphism (SNP), and gene correlation analysis were performed using GeneNetwork. Gene set enrichment analysis was performed using WebGestalt, and gene network construction was performed using the Gene Cohesion Analysis Tool. Results We found Myo7a to be cis-regulated, with varied levels of expression across BXD strains. Here, we propose a genetic network with 40 genes whose expression is highly correlated with Myo7a. Among these genes, six have been linked to retinal diseases, three to deafness, and five share a transcription factor with Myo7a. Gene ontology and pathway analysis revealed a strong connection among ion channel activity, Myo7a, and US. Conclusions Although Myo7a is a causal gene of US type I, this gene works with many other genes and pathways to affect the severity of US. Many of the genes found in the genetic network, pathways, and gene ontology categories of Myo7a are related to either deafness or blindness. Further investigation is needed to examine the specific relationships between these genes, which may assist in the treatment of US.
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Affiliation(s)
- Ye Lu
- Department of Ophthalmology, The First Affiliated Hospital, Zhejiang University College of Medicine, Hangzhou, China
| | - Diana Zhou
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN
| | - Rebecca King
- Department of Ophthalmology and Emory Eye Center, Emory University, Atlanta, GA
| | - Shuang Zhu
- Department of Ophthalmology & Visual Sciences, University of Texas Medical Branch, Galveston, TX
| | - Claire L. Simpson
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN
| | - Byron C. Jones
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN
| | - Wenbo Zhang
- Department of Ophthalmology & Visual Sciences, University of Texas Medical Branch, Galveston, TX
| | - Eldon E. Geisert
- Department of Ophthalmology and Emory Eye Center, Emory University, Atlanta, GA
| | - Lu Lu
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN
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8
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Reed C, Baba H, Zhu Z, Erk J, Mootz JR, Varra NM, Williams RW, Phillips TJ. A Spontaneous Mutation in Taar1 Impacts Methamphetamine-Related Traits Exclusively in DBA/2 Mice from a Single Vendor. Front Pharmacol 2018; 8:993. [PMID: 29403379 PMCID: PMC5786530 DOI: 10.3389/fphar.2017.00993] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 12/26/2017] [Indexed: 01/01/2023] Open
Abstract
Major gene effects on traits associated with substance use disorders are rare. Previous findings in methamphetamine drinking (MADR) lines of mice, bred for high or low voluntary MA intake, and in null mutants demonstrate a major impact of the trace amine-associated receptor 1 (Taar1) gene on a triad of MA-related traits: MA consumption, MA-induced conditioned taste aversion and MA-induced hypothermia. While inbred strains are fundamentally genetically stable, rare spontaneous mutations can become fixed and result in new or aberrant phenotypes. A single nucleotide polymorphism in Taar1 that encodes a missense proline to threonine mutation in the second transmembrane domain (Taar1m1J) has been identified in the DBA/2J strain. MA is an agonist at this receptor, but the receptor produced by Taar1m1J does not respond to MA or endogenous ligands. In the present study, we used progeny of the C57BL/6J × DBA/2J F2 cross, the MADR lines, C57BL/6J × DBA/2J recombinant inbred strains, and DBA/2 mice sourced from four vendors to further examine Taar1-MA phenotype relations and to define the chronology of the fixation of the Taar1m1J mutation. Mice homozygous for Taar1m1J were found at high frequency early in selection for high MA intake in multiple replicates of the high MADR line, whereas Taar1m1J homozygotes were absent in the low MADR line. The homozygous Taar1m1J genotype is causally linked to increased MA intake, reduced MA-induced conditioned taste aversion, and reduced MA-induced hypothermia across models. Genotype-phenotype correlations range from 0.68 to 0.96. This Taar1 polymorphism exists in DBA/2J mice sourced directly from The Jackson Laboratory, but not DBA/2 mice sourced from Charles River (DBA/2NCrl), Envigo (formerly Harlan Sprague Dawley; DBA/2NHsd) or Taconic (DBA/2NTac). By genotyping archived samples from The Jackson Laboratory, we have determined that this mutation arose in 2001–2003. Our data strengthen the conclusion that the mutant Taar1m1J allele, which codes for a non-functional receptor protein, increases risk for multiple MA-related traits, including MA intake, in homozygous Taar1m1J individuals.
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Affiliation(s)
- Cheryl Reed
- Department of Behavioral Neuroscience and Methamphetamine Abuse Research Center, Oregon Health & Science University, Portland, OR, United States
| | - Harue Baba
- Department of Behavioral Neuroscience and Methamphetamine Abuse Research Center, Oregon Health & Science University, Portland, OR, United States
| | - Zhen Zhu
- Department of Behavioral Neuroscience and Methamphetamine Abuse Research Center, Oregon Health & Science University, Portland, OR, United States
| | - Jason Erk
- Department of Behavioral Neuroscience and Methamphetamine Abuse Research Center, Oregon Health & Science University, Portland, OR, United States
| | - John R Mootz
- Department of Behavioral Neuroscience and Methamphetamine Abuse Research Center, Oregon Health & Science University, Portland, OR, United States
| | - Nicholas M Varra
- Department of Behavioral Neuroscience and Methamphetamine Abuse Research Center, Oregon Health & Science University, Portland, OR, United States
| | - Robert W Williams
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Sciences Center, Memphis, TN, United States
| | - Tamara J Phillips
- Department of Behavioral Neuroscience and Methamphetamine Abuse Research Center, Oregon Health & Science University, Portland, OR, United States.,VA Portland Health Care System, Portland, OR, United States
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Systems genetics identifies a role for Cacna2d1 regulation in elevated intraocular pressure and glaucoma susceptibility. Nat Commun 2017; 8:1755. [PMID: 29176626 PMCID: PMC5701146 DOI: 10.1038/s41467-017-00837-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 06/28/2017] [Indexed: 12/21/2022] Open
Abstract
Glaucoma is a multi-factorial blinding disease in which genetic factors play an important role. Elevated intraocular pressure is a highly heritable risk factor for primary open angle glaucoma and currently the only target for glaucoma therapy. Our study helps to better understand underlying genetic and molecular mechanisms that regulate intraocular pressure, and identifies a new candidate gene, Cacna2d1, that modulates intraocular pressure and a promising therapeutic, pregabalin, which binds to CACNA2D1 protein and lowers intraocular pressure significantly. Because our study utilizes a genetically diverse population of mice with known sequence variants, we are able to determine that the intraocular pressure-lowering effect of pregabalin is dependent on the Cacna2d1 haplotype. Using human genome-wide association study (GWAS) data, evidence for association of a CACNA2D1 single-nucleotide polymorphism and primary open angle glaucoma is found. Importantly, these results demonstrate that our systems genetics approach represents an efficient method to identify genetic variation that can guide the selection of therapeutic targets. Elevated intraocular pressure (IOP) is a heritable risk factor for primary open angle glaucoma. Using forward mouse genetics, cell biology, pharmacology and human genetic data, the authors identify CACNA2D1 as an IOP risk gene that can be therapeutically targeted by the drug pregabalin in animal models.
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Analyses of differentially expressed genes after exposure to acute stress, acute ethanol, or a combination of both in mice. Alcohol 2017; 58:139-151. [PMID: 28027852 DOI: 10.1016/j.alcohol.2016.08.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 08/10/2016] [Accepted: 08/10/2016] [Indexed: 12/31/2022]
Abstract
Alcohol abuse is a complex disorder, which is confounded by other factors, including stress. In the present study, we examined gene expression in the hippocampus of BXD recombinant inbred mice after exposure to ethanol (NOE), stress (RSS), and the combination of both (RSE). Mice were given an intraperitoneal (i.p.) injection of 1.8 g/kg ethanol or saline, and subsets of both groups were exposed to acute restraint stress for 15 min or controls. Gene expression in the hippocampus was examined using microarray analysis. Genes that were significantly (p < 0.05, q < 0.1) differentially expressed were further evaluated. Bioinformatic analyses were predominantly performed using tools available at GeneNetwork.org, and included gene ontology, presence of cis-regulation or polymorphisms, phenotype correlations, and principal component analyses. Comparisons of differential gene expression between groups showed little overlap. Gene Ontology demonstrated distinct biological processes in each group with the combined exposure (RSE) being unique from either the ethanol (NOE) or stress (RSS) group, suggesting that the interaction between these variables is mediated through diverse molecular pathways. This supports the hypothesis that exposure to stress alters ethanol-induced gene expression changes and that exposure to alcohol alters stress-induced gene expression changes. Behavior was profiled in all groups following treatment, and many of the differentially expressed genes are correlated with behavioral variation within experimental groups. Interestingly, in each group several genes were correlated with the same phenotype, suggesting that these genes are the potential origins of significant genetic networks. The distinct sets of differentially expressed genes within each group provide the basis for identifying molecular networks that may aid in understanding the complex interactions between stress and ethanol, and potentially provide relevant therapeutic targets. Using Ptp4a1, a candidate gene underlying the quantitative trait locus for several of these phenotypes, and network analyses, we show that a large group of differentially expressed genes in the NOE group are highly interrelated, some of which have previously been linked to alcohol addiction or alcohol-related phenotypes.
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Chintalapudi SR, Jablonski MM. Systems Genetics Analysis to Identify the Genetic Modulation of a Glaucoma-Associated Gene. Methods Mol Biol 2017; 1488:391-417. [PMID: 27933535 DOI: 10.1007/978-1-4939-6427-7_18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
Loss of retinal ganglion cells (RGCs) is one of the hallmarks of retinal neurodegenerative diseases, glaucoma being one of the most common. Recently, γ-synuclein (SNCG) was shown to be highly expressed in the somas and axons of RGCs. In various mouse models of glaucoma, downregulation of Sncg gene expression correlates with RGC loss. To investigate the regulation of Sncg in RGCs, we used a systems genetics approach to identify a gene that modulates the expression of Sncg, followed by confirmatory studies in both healthy and diseased retinas. We found that chromosome 1 harbors an eQTL that modulates the expression of Sncg in the mouse retina and identified Pfdn2 as the candidate upstream modulator of Sncg expression. Downregulation of Pfdn2 in enriched RGCs causes a concomitant reduction in Sncg. In this chapter, we describe our strategy and methods for identifying and confirming a genetic modulation of a glaucoma-associated gene. A similar method can be applied to other genes expressed in other tissues.
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Affiliation(s)
- Sumana R Chintalapudi
- Department of Anatomy and Neurobiology, Hamilton Eye Institute, The University of Tennessee Health Science Center, 930 Madison Ave., Suite 710, Memphis, TN, 38163, USA
| | - Monica M Jablonski
- Department of Ophthalmology, Hamilton Eye Institute, The University of Tennessee Health Science Center, 930 Madison Ave., Suite 710, Memphis, TN, 38163, USA. .,Department of Anatomy and Neurobiology, Hamilton Eye Institute, The University of Tennessee Health Science Center, 930 Madison Ave., Suite 710, Memphis, TN, 38163, USA. .,Department of Pharmaceutical Sciences, Hamilton Eye Institute, The University of Tennessee Health Science Center, 930 Madison Ave., Suite 710, Memphis, TN, 38163, USA.
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Chintalapudi SR, Wang X, Li H, Lau YHC, Williams RW, Jablonski MM. Genetic and immunohistochemical analysis of HSPA5 in mouse and human retinas. Mol Vis 2016; 22:1318-1331. [PMID: 27881906 PMCID: PMC5108462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 11/08/2016] [Indexed: 11/06/2022] Open
Abstract
PURPOSE Photoreceptor degenerative diseases are among the leading causes of vision loss. Although the causative genetic mutations are often known, mechanisms leading to photoreceptor degeneration remain poorly defined. We have previously demonstrated that the photoreceptor membrane-associated protein XAP-1 antigen is a product of the HSPA5 gene. In this study, we used systems genetic methods, statistical modeling, and immunostaining to identify and analyze candidate genes that modulate Hspa5 expression in the retina. METHODS Quantitative trait locus (QTL) mapping was used to map the genomic region that regulates Hspa5 in the cross between C57BL/6J X DBA/2J mice (BXD) genetic reference panel. The stepwise refinement of candidate genes was based on expression QTL mapping, gene expression correlation analyses (direct and partial), and analysis of regional sequence variants. The subcellular localization of candidate proteins and HSPA5 in mouse and human retinas was evaluated by immunohistochemistry. Differences in the localization of extracellular HSPA5 were assessed between healthy human donor and atrophic age-related macular degeneration (AMD) donor eyes. RESULTS In the eyes of healthy mice, extracellular HSPA5 was confined to the area around the cone photoreceptor outer segments. Mapping variation in Hspa5 mRNA expression levels in the retina revealed a statistically significant trans-acting expression QTL (eQTL) on Chromosome 2 (Chr 2) and a suggestive locus on Chr 15. Sulf2 on Chr 2 was the strongest candidate gene based on partial correlation analysis, Pearson correlation with Hspa5, expression levels in the retina, a missense variant in exon 14, and its reported function in the extracellular matrix and interphotoreceptor matrix. SULF2 is localized to the rod and cone photoreceptors in both human and mouse retinas. In human retinas with no pathology, extracellular HSPA5 was localized around many cones within the macular area. In contrast, fewer HSPA5-immunopositive cones were observed in the retinas from AMD donors. CONCLUSIONS We identified Sulf2 as a candidate gene modulating the Hspa5 expression in the retina. The preferential loss of HSPA5 in the interphotoreceptor matrix around cone photoreceptors in atrophic AMD retinas opens up new avenues for exploring the changes in interphotoreceptor matrix (IPM) that are associated with macular disease.
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Affiliation(s)
- Sumana R. Chintalapudi
- Department of Ophthalmology, Hamilton Eye Institute, The University of Tennessee Health Science Center, Memphis, TN,Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN
| | - XiaoFei Wang
- Department of Ophthalmology, Hamilton Eye Institute, The University of Tennessee Health Science Center, Memphis, TN
| | - Huiling Li
- Department of Ophthalmology, Hamilton Eye Institute, The University of Tennessee Health Science Center, Memphis, TN,Department of Ophthalmology, the Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yin H. Chan Lau
- Department of Ophthalmology, Hamilton Eye Institute, The University of Tennessee Health Science Center, Memphis, TN
| | - Robert W. Williams
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN,Department of Genetics, Genomics and Informatics, The University of Tennessee Health Science Center, Memphis, TN
| | - Monica M. Jablonski
- Department of Ophthalmology, Hamilton Eye Institute, The University of Tennessee Health Science Center, Memphis, TN,Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN,Department of Pharmaceutical Sciences, The University of Tennessee Health Science Center, Memphis, TN
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Chintalapudi SR, Djenderedjian L, Stiemke AB, Steinle JJ, Jablonski MM, Morales-Tirado VM. Isolation and Molecular Profiling of Primary Mouse Retinal Ganglion Cells: Comparison of Phenotypes from Healthy and Glaucomatous Retinas. Front Aging Neurosci 2016; 8:93. [PMID: 27242509 PMCID: PMC4870266 DOI: 10.3389/fnagi.2016.00093] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 04/12/2016] [Indexed: 12/11/2022] Open
Abstract
Loss of functional retinal ganglion cells (RGC) is an element of retinal degeneration that is poorly understood. This is in part due to the lack of a reliable and validated protocol for the isolation of primary RGCs. Here we optimize a feasible, reproducible, standardized flow cytometry-based protocol for the isolation and enrichment of homogeneous RGC with the Thy1.2(hi)CD48(neg)CD15(neg)CD57(neg) surface phenotype. A three-step validation process was performed by: (1) genomic profiling of 25-genes associated with retinal cells; (2) intracellular labeling of homogeneous sorted cells for the intracellular RGC-markers SNCG, brain-specific homeobox/POU domain protein 3A (BRN3A), TUJ1, and RNA-binding protein with multiple splicing (RBPMS); and (3) by applying the methodology on RGC from a mouse model with elevated intraocular pressure (IOP) and optic nerve damage. Use of primary RGC cultures will allow for future careful assessment of important cell specific pathways in RGC to provide mechanistic insights into the declining of visual acuity in aged populations and those suffering from retinal neurodegenerative diseases.
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Affiliation(s)
- Sumana R. Chintalapudi
- Department of Ophthalmology, The University of Tennessee Health Science CenterMemphis, TN, USA
| | - Levon Djenderedjian
- Department of Ophthalmology, The University of Tennessee Health Science CenterMemphis, TN, USA
| | - Andrew B. Stiemke
- Department of Ophthalmology, The University of Tennessee Health Science CenterMemphis, TN, USA
| | - Jena J. Steinle
- Department of Anatomy and Cell Biology, Wayne State UniversityDetroit, MI, USA
- Department of Ophthalmology, Wayne State UniversityDetroit, MI, USA
| | - Monica M. Jablonski
- Department of Ophthalmology, The University of Tennessee Health Science CenterMemphis, TN, USA
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science CenterMemphis, TN, USA
- Department of Pharmaceutical Sciences, The University of Tennessee Health Science CenterMemphis, TN, USA
| | - Vanessa M. Morales-Tirado
- Department of Ophthalmology, The University of Tennessee Health Science CenterMemphis, TN, USA
- Department of Microbiology, Immunology and Biochemistry, The University of Tennessee Health Science CenterMemphis, TN, USA
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Shi X, Walter NAR, Harkness JH, Neve KA, Williams RW, Lu L, Belknap JK, Eshleman AJ, Phillips TJ, Janowsky A. Genetic Polymorphisms Affect Mouse and Human Trace Amine-Associated Receptor 1 Function. PLoS One 2016; 11:e0152581. [PMID: 27031617 PMCID: PMC4816557 DOI: 10.1371/journal.pone.0152581] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 03/16/2016] [Indexed: 12/15/2022] Open
Abstract
Methamphetamine (MA) and neurotransmitter precursors and metabolites such as tyramine, octopamine, and β-phenethylamine stimulate the G protein-coupled trace amine-associated receptor 1 (TAAR1). TAAR1 has been implicated in human conditions including obesity, schizophrenia, depression, fibromyalgia, migraine, and addiction. Additionally TAAR1 is expressed on lymphocytes and astrocytes involved in inflammation and response to infection. In brain, TAAR1 stimulation reduces synaptic dopamine availability and alters glutamatergic function. TAAR1 is also expressed at low levels in heart, and may regulate cardiovascular tone. Taar1 knockout mice orally self-administer more MA than wild type and are insensitive to its aversive effects. DBA/2J (D2) mice express a non-synonymous single nucleotide polymorphism (SNP) in Taar1 that does not respond to MA, and D2 mice are predisposed to high MA intake, compared to C57BL/6 (B6) mice. Here we demonstrate that endogenous agonists stimulate the recombinant B6 mouse TAAR1, but do not activate the D2 mouse receptor. Progeny of the B6XD2 (BxD) family of recombinant inbred (RI) strains have been used to characterize the genetic etiology of diseases, but contrary to expectations, BXDs derived 30-40 years ago express only the functional B6 Taar1 allele whereas some more recently derived BXD RI strains express the D2 allele. Data indicate that the D2 mutation arose subsequent to derivation of the original RIs. Finally, we demonstrate that SNPs in human TAAR1 alter its function, resulting in expressed, but functional, sub-functional and non-functional receptors. Our findings are important for identifying a predisposition to human diseases, as well as for developing personalized treatment options.
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Affiliation(s)
- Xiao Shi
- Veterans Affairs Portland Health Care System, Portland, Oregon, United States of America
- The Methamphetamine Abuse Research Center, Oregon Health & Science University, Portland, Oregon, United States of America
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Nicole A. R. Walter
- Veterans Affairs Portland Health Care System, Portland, Oregon, United States of America
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon, United States of America
| | - John H. Harkness
- Veterans Affairs Portland Health Care System, Portland, Oregon, United States of America
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Kim A. Neve
- Veterans Affairs Portland Health Care System, Portland, Oregon, United States of America
- The Methamphetamine Abuse Research Center, Oregon Health & Science University, Portland, Oregon, United States of America
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Robert W. Williams
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Lu Lu
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
- Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, Jiangsu, China
| | - John K. Belknap
- Veterans Affairs Portland Health Care System, Portland, Oregon, United States of America
- The Methamphetamine Abuse Research Center, Oregon Health & Science University, Portland, Oregon, United States of America
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Amy J. Eshleman
- Veterans Affairs Portland Health Care System, Portland, Oregon, United States of America
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Tamara J. Phillips
- Veterans Affairs Portland Health Care System, Portland, Oregon, United States of America
- The Methamphetamine Abuse Research Center, Oregon Health & Science University, Portland, Oregon, United States of America
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Aaron Janowsky
- Veterans Affairs Portland Health Care System, Portland, Oregon, United States of America
- The Methamphetamine Abuse Research Center, Oregon Health & Science University, Portland, Oregon, United States of America
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon, United States of America
- Department of Psychiatry, Oregon Health & Science University, Portland, Oregon, United States of America
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15
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Lu H, Lu L, Williams RW, Jablonski MM. Iris transillumination defect and its gene modulators do not correlate with intraocular pressure in the BXD family of mice. Mol Vis 2016; 22:224-33. [PMID: 27011731 PMCID: PMC4783577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 03/02/2016] [Indexed: 11/16/2022] Open
Abstract
PURPOSE Intraocular pressure (IOP) is currently the only treatable phenotype associated with primary open angle glaucoma (POAG). Our group has developed the BXD murine panel for identifying genetic modulators of the various endophenotypes of glaucoma, including pigment dispersion, IOP, and retinal ganglion cell (RGC) death. The BXD family consists of the inbred progeny of crosses between the C57BL/6J (B6) strain and the glaucoma-prone DBA/2J (D2) strain that has mutations in Tyrp1 and Gpnmb. The role of these genes in the iris transillumination defect (TID) has been well documented; however, their possible roles in modulating IOP during glaucoma onset and progression are yet not well understood. METHODS We used the IOP data sets and the Eye M430v2 (Sep08) RMA Database available on GeneNetwork to determine whether mutations in Tyrp1 and Gpnmb or TIDs have a direct role in the elevation of IOP in the BXD family. We also determined whether TIDs and IOP are coregulated. RESULTS As expected, Tyrp1 and Gpnmb expression levels showed a high degree of correlation with TIDs. However, there was no correlation between the expression of these genes and IOP. Moreover, unlike TIDs, IOP did not map to either the Tyrp1 or Gpnmb locus. Although the Tyrp1 and Gpnmb mutations in BXD strains are a prerequisite for the development of TID, they are not required for or associated with elevated IOP. CONCLUSIONS Genetic modulators of IOP thus may be independently identified using the full array of BXD mice without concern for the presence of TIDs or mutations in Typr1 and/or Gpnmb.
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Affiliation(s)
- Hong Lu
- Department of Ophthalmology, Hamilton Eye Institute, University of Tennessee Health Science Center, Memphis, TN,Department of Ophthalmology, Nantong Eye Institute, Affiliated Hospital of Nantong University, Nantong, China
| | - Lu Lu
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN,Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, China
| | - Robert W. Williams
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN
| | - Monica M. Jablonski
- Department of Ophthalmology, Hamilton Eye Institute, University of Tennessee Health Science Center, Memphis, TN
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16
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Chintalapudi SR, Morales-Tirado VM, Williams RW, Jablonski MM. Multipronged approach to identify and validate a novel upstream regulator of Sncg in mouse retinal ganglion cells. FEBS J 2016; 283:678-93. [PMID: 26663874 DOI: 10.1111/febs.13620] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 10/22/2015] [Accepted: 12/03/2015] [Indexed: 11/26/2022]
Abstract
Loss of retinal ganglion cells (RGCs) is one of the hallmarks of retinal neurodegenerative diseases, glaucoma being one of the most common. Mechanistic studies on RGCs are hindered by the lack of sufficient primary cells and consensus regarding their signature markers. Recently, γ-synuclein (SNCG) has been shown to be highly expressed in the somas and axons of RGCs. In various mouse models of glaucoma, downregulation of Sncg gene expression correlates with RGC loss. To investigate the role of Sncg in RGCs, we used a novel systems genetics approach to identify a gene that modulates Sncg expression, followed by confirmatory studies in both healthy and diseased retinae. We found that chromosome 1 harbors an expression quantitative trait locus that modulates Sncg expression in the mouse retina, and identified the prefoldin-2 (PFDN2) gene as the candidate upstream modulator of Sncg expression. Our immunohistochemical analyses revealed similar expression patterns in both mouse and human healthy retinae, with PFDN2 colocalizing with SNCG in RGCs and their axons. In contrast, in retinae from glaucoma subjects, SNCG levels were significantly reduced, although PFDN2 levels were maintained. Using a novel flow cytometry-based RGC isolation method, we obtained viable populations of murine RGCs. Knocking down Pfdn2 expression in primary murine RGCs significantly reduced Sncg expression, confirming that Pfdn2 regulates Sncg expression in murine RGCs. Gene Ontology analysis indicated shared mitochondrial function associated with Sncg and Pfdn2. These data solidify the relationship between Sncg and Pfdn2 in RGCs, and provide a novel mechanism for maintaining RGC health.
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Affiliation(s)
- Sumana R Chintalapudi
- Department of Ophthalmology, The Hamilton Eye Institute, The University of Tennessee Health Science Center, Memphis, TN, USA.,Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, USA
| | - Vanessa M Morales-Tirado
- Department of Ophthalmology, The Hamilton Eye Institute, The University of Tennessee Health Science Center, Memphis, TN, USA.,Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, USA.,Department of Microbiology, Immunology and Biochemistry, The University of Tennessee Health Science Center, Memphis, TN, USA
| | - Robert W Williams
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, USA.,Department of Genetics, Genomics and Informatics, The University of Tennessee Health Science Center, Memphis, TN, USA
| | - Monica M Jablonski
- Department of Ophthalmology, The Hamilton Eye Institute, The University of Tennessee Health Science Center, Memphis, TN, USA.,Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, USA
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17
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Ibrahim MM, Abd-Elgawad AEH, Soliman OAE, Jablonski MM. Natural Bioadhesive Biodegradable Nanoparticle-Based Topical Ophthalmic Formulations for Management of Glaucoma. Transl Vis Sci Technol 2015; 4:12. [PMID: 26175958 PMCID: PMC4497485 DOI: 10.1167/tvst.4.3.12] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 05/07/2015] [Indexed: 01/20/2023] Open
Abstract
PURPOSE We prepared and characterized topical ophthalmic formulations containing brimonidine-loaded bioadhesive cationic chitosan or anionic alginate nanoparticles (NPs) for sustained release of brimonidine as once daily regimen for management of glaucoma. METHODS Nanoparticles were prepared using a spontaneous emulsification solvent diffusion method. Different concentrations of polymers, emulsifiers, and NPs stabilizers were used for formulation optimization. Nanoparticles were characterized regarding particle size, zeta potential, morphology, and drug content. Brimonidine-loaded NPs were incorporated into eye drops, a temperature-triggered in situ gelling system, and a preformed gel. They then were characterized regarding their pH, viscosity, uniformity of drug content, in vitro release characteristics, in vitro cytotoxicity, and in vivo intraocular pressure (IOP) lowering effects. RESULTS Characteristics of optimized brimonidine-loaded chitosan and alginate NPs, respectively, are: particle size, 115.67 ± 3.58 and 157.67 ± 5.53 nm; zeta potential, +35.27 ± 3.39 and -37.8 ± 3.77 mV; encapsulation efficiency, 74.34% ± 2.05% and 70.40% ± 2.77%; drug loading, 11.81% ± 0.67% and 13.14% ± 0.90%; and yield, 87.91% ± 5.92% and 76.53% ± 3.32%. Transmission electron microscope (TEM) analyses revealed that NPs have spherical shapes with a dense core and distinct coat. Formulations possessed uniform drug content. Furthermore, pH and viscosity were compatible with the eye. Formulations showed a sustained release without any burst effect with a Higuchi non-Fickian diffusion mechanism. Cytotoxicity studies revealed that all formulations are biocompatible. Importantly, all formulations possessed a sustained IOP lowering effect compared to the marketed brimonidine tartrate eye drops. CONCLUSIONS These formulations provide a great improvement in topical ocular brimonidine delivery. The application of a single drop is sufficient to provide extended IOP reduction, which should improve patient compliance. TRANSLATIONAL RELEVANCE We have developed a novel biocompatible topical delivery system for brimonidine, a first line glaucoma medication. Once daily application should have positive effects on patient compliance and, therefore, preservation of vision.
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Affiliation(s)
- Mohammed Mostafa Ibrahim
- Department of Ophthalmology, Hamilton Eye Institute, University of Tennessee Health Science Center, Memphis, TN, USA
- Department of Pharmaceutics, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt
| | | | | | - Monica M. Jablonski
- Department of Ophthalmology, Hamilton Eye Institute, University of Tennessee Health Science Center, Memphis, TN, USA
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18
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Novel Topical Ophthalmic Formulations for Management of Glaucoma. Pharm Res 2013; 30:2818-31. [DOI: 10.1007/s11095-013-1109-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 06/04/2013] [Indexed: 10/26/2022]
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19
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Swaminathan S, Lu H, Williams RW, Lu L, Jablonski MM. Genetic modulation of the iris transillumination defect: a systems genetics analysis using the expanded family of BXD glaucoma strains. Pigment Cell Melanoma Res 2013; 26:487-98. [PMID: 23582180 PMCID: PMC3752936 DOI: 10.1111/pcmr.12106] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Accepted: 04/10/2013] [Indexed: 11/29/2022]
Abstract
We investigated the contributions of Tyrp1 and Gpnmb to the iris transillumination defect (TID) in five age cohorts of BXD mice. Using systems genetics, we also evaluated the role of other known pigmentation genes (PGs). Mapping studies indicate that Tyrp1 contributes to the phenotype at all ages, yet the TID maps to Gpnmb only in the oldest cohort. Composite interval mapping reveals secondary loci viz. Oca2, Myo5a, Prkcz, and Zbtb20 that modulate the phenotype in the age groups up to 10–13 months. The contributions of Tyrp1 and Gpnmb were highly significant in all age cohorts. Moreover, in young mice, all six gene candidates had substantial interactions in our model. Our model accounted for 71–88% of the explained variance of the TID phenotype across the age bins. These results demonstrate that along with Tyrp1 and Gpnmb, Oca2, Myo5a, Prkcz, and Zbtb20 modulate the TID in an age-dependent manner.
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Affiliation(s)
- Shankar Swaminathan
- Department of Ophthalmology, Hamilton Eye Institute, University of Tennessee Health Science Center, Memphis, TN, USA
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21
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Lu H, Li L, Watson ER, Williams RW, Geisert EE, Jablonski MM, Lu L. Complex interactions of Tyrp1 in the eye. Mol Vis 2011; 17:2455-68. [PMID: 21976956 PMCID: PMC3185026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Accepted: 09/12/2011] [Indexed: 11/20/2022] Open
Abstract
PURPOSE To use a systems genetics approach to construct and analyze co-expression networks that are causally linked to mutations in a key pigementation gene, tyrosinase-related protein 1 (Tyrp1), that is associated both with oculocutaneous albinism type 3 (OCA3) in humans and with glaucoma in mice. METHODS Gene expression patterns were measured in whole eyes of a large family of BXD recombinant inbred (RI) mice derived from parental lines that encode for wildtype (C57BL/6J) and mutant (DBA/2J) Tyrp1. Protein levels of Tyrp1 were measured in whole eyes and isolated irides. Bioinformatics analyses were performed on the expression data along with our archived sequence data. Separate data sets were generated which were comprised of strains that harbor either wildtype or mutant Tyrp1 and each was mined individually to identify gene networks that covary significantly with each isoform of Tyrp1. Ontology trees and network graphs were generated to probe essential function and statistical significance of covariation. Genes with strong covariance in wildtype mice were assembled into genome-wide heatmaps for cohorts carrying either wildtype or mutant Tyrp1. RESULTS Single nucleotide polymorphism (SNP) analysis verified the presence of the Tyrp1b mutation in the Tyrp1 gene. Message levels were greater in BXD strains with the mutant Tyrp1. Interval mapping of these BXD mice revealed a strong expression quantitative trait locus (eQTL) on Chr 4 at the location of the gene itself. Composite mapping revealed a suggestive eQTL on Chr 9 at the location of myosin-Va (Myo5a), mutations in which are known as dilute. Enriched biologic processes associated with wildtype Tyrp1 included pigmentation, melanin biosynthetic process, and mesenchymal cell development, while associations with the mutant gene included categories of neural crest cell development, protein metabolic processes and glycoprotein metabolic processes. Genome-wide heatmaps revealed strong candidate cis-eQTLs on Chr 4 at Tyrp1 and on Chr 9 at Myo5a in all mice. In the wildtype data set, Tyrp1 was an upstream regulator of six pigmentation and two mesenchyme genes. In addition, five genes, including Tyrp1, were at least partially regulated by Myo5a. Analyses of the strains harboring the mutant gene revealed significant loss of correlation to traditional genes and gain of correlation to genes with little or no functional relationship. CONCLUSIONS These findings indicate that the Tyrp1(b) mutation modifies the pathways and gene networks in which Tyrp1 functions. Our results also indicate direct and indirect regulatory control of Tyrp1 and other pigmentation and mesenchymal genes by Myo5a. Lastly, we find that the mutations reduce the ability of Tyrp1 to regulate expression of other genes that participate in pigmentation metabolism.
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Affiliation(s)
- Hong Lu
- Department of Ophthalmology, Hamilton Eye Institute, University of Tennessee Health Science Center, Memphis, TN,Department of Ophthalmology, Affiliated Hospital of Nantong University, Nantong, China
| | - Liyuan Li
- Department of Ophthalmology, Hamilton Eye Institute, University of Tennessee Health Science Center, Memphis, TN
| | - Edmond R. Watson
- Department of Ophthalmology, Hamilton Eye Institute, University of Tennessee Health Science Center, Memphis, TN
| | - Robert W. Williams
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN
| | - Eldon E. Geisert
- Department of Ophthalmology, Hamilton Eye Institute, University of Tennessee Health Science Center, Memphis, TN,Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN
| | - Monica M. Jablonski
- Department of Ophthalmology, Hamilton Eye Institute, University of Tennessee Health Science Center, Memphis, TN,Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN
| | - Lu Lu
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN,Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, China
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22
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Freeman NE, Templeton JP, Orr WE, Lu L, Williams RW, Geisert EE. Genetic networks in the mouse retina: growth associated protein 43 and phosphatase tensin homolog network. Mol Vis 2011; 17:1355-72. [PMID: 21655357 PMCID: PMC3108897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Accepted: 05/21/2011] [Indexed: 10/26/2022] Open
Abstract
PURPOSE The present study examines the structure and covariance of endogenous variation in gene expression across the recently expanded family of C57BL/6J (B) X DBA/2J (D) Recombinant Inbred (BXD RI) strains of mice. This work is accompanied by a highly interactive database that can be used to generate and test specific hypotheses. For example, we define the genetic network regulating growth associated protein 43 (Gap43) and phosphatase tensin homolog (Pten). METHODS The Hamilton Eye Institute (HEI) Retina Database within GeneNetwork features the data analysis of 346 Illumina Sentrix BeadChip Arrays (mouse whole genome-6 version 2). Eighty strains of mice are presented, including 75 BXD RI strains, the parental strains (C57BL/6J and DBA/2J), the reciprocal crosses, and the BALB/cByJ mice. Independent biologic samples for at least two animals from each gender were obtained with a narrow age range (48 to 118 days). Total RNA was prepared followed by the production of biotinylated cRNAs, which were pipetted into the Mouse WG-6V2 arrays. The data was globally normalized with rank invariant and stabilization (2z+8). RESULTS The HEI Retina Database is located on the GeneNetwork website. The database was used to extract unique transcriptome signatures for specific cell types in the retina (retinal pigment epithelial, amacrine, and retinal ganglion cells). Two genes associated with axonal outgrowth (Gap43 and Pten) were used to display the power of this new retina database. Bioinformatic tools located within GeneNetwork in conjunction with the HEI Retina Database were used to identify the unique signature Quantitative Trait Loci (QTLs) for Gap43 and Pten on chromosomes 1, 2, 12, 15, 16, and 19. Gap43 and Pten possess networks that are similar to ganglion cell networks that may be associated with axonal growth in the mouse retina. This network involves high correlations of transcription factors (SRY sex determining region Y-box 2 [Sox2], paired box gene 6 [Pax6], and neurogenic differentiation 1 [Neurod1]), and genes involved in DNA binding (proliferating cell nuclear antigen [Pcna] and zinc finger, BED-type containing 4 [Zbed4]), as well as an inhibitor of DNA binding (inhibitor of DNA binding 2, dominant negative helix-loop-helix protein [Id2]). Furthermore, we identified the potential upstream modifiers on chromosome 2 (teashirt zinc finger homeobox 2 [Tshz2], RNA export 1 homolog [Rae1] and basic helix-loop-helix domain contatining, class B4 [Bhlhb4]) on chromosome 15 (RAB, member of RAS oncogene family-like 2a [Rabl2a], phosphomannomutase 1 [Pmm1], copine VIII [Cpne8], and fibulin 1 [Fbln1]). CONCLUSIONS The endogenous variation in mRNA levels among BXD RI strains can be used to explore and test expression networks underlying variation in retina structure, function, and disease susceptibility. The Gap43 and Pten network highlights the covariance of gene expression and forms a molecular network associated with axonal outgrowth in the adult retina.
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Affiliation(s)
| | | | - William E. Orr
- Department of Ophthalmology and Center for Vision Research, Memphis, TN
| | - Lu Lu
- Department of Anatomy and Neurobiology and Center for Integrative and Translational Genomics, University of Tennessee Health Science Center, Memphis, TN
| | - Robert W. Williams
- Department of Anatomy and Neurobiology and Center for Integrative and Translational Genomics, University of Tennessee Health Science Center, Memphis, TN
| | - Eldon E. Geisert
- Department of Ophthalmology and Center for Vision Research, Memphis, TN
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