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Sin TN, Kim S, Li Y, Wang J, Chen R, Chung SH, Kim S, Casanova MI, Park S, Smit-McBride Z, Sun N, Pomerantz O, Roberts JA, Guan B, Hufnagel RB, Moshiri A, Thomasy SM, Sieving PA, Yiu G. A Spontaneous Nonhuman Primate Model of Myopic Foveoschisis. Invest Ophthalmol Vis Sci 2023; 64:18. [PMID: 36689233 PMCID: PMC9896856 DOI: 10.1167/iovs.64.1.18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 01/05/2023] [Indexed: 01/24/2023] Open
Abstract
Purpose Foveoschisis involves the pathologic splitting of retinal layers at the fovea, which may occur congenitally in X-linked retinoschisis (XLRS) or as an acquired complication of myopia. XLRS is attributed to functional loss of the retinal adhesion protein retinoschisin 1 (RS1), but the pathophysiology of myopic foveoschisis is unclear due to the lack of animal models. Here, we characterized a novel nonhuman primate model of myopic foveoschisis through clinical examination and multimodal imaging followed by morphologic, cellular, and transcriptional profiling of retinal tissues and genetic analysis. Methods We identified a rhesus macaque with behavioral and anatomic features of myopic foveoschisis, and monitored disease progression over 14 months by fundus photography, fluorescein angiography, and optical coherence tomography (OCT). After necropsy, we evaluated anatomic and cellular changes by immunohistochemistry and transcriptomic changes using single-nuclei RNA-sequencing (snRNA-seq). Finally, we performed Sanger and whole exome sequencing with focus on the RS1 gene. Results Affected eyes demonstrated posterior hyaloid traction and progressive splitting of the outer plexiform layer on OCT. Immunohistochemistry showed increased GFAP expression in Müller glia and loss of ramified Iba-1+ microglia, suggesting macro- and microglial activation with minimal photoreceptor alterations. SnRNA-seq revealed gene expression changes predominantly in cones and retinal ganglion cells involving chromatin modification, suggestive of cellular stress at the fovea. No defects in the RS1 gene or its expression were detected. Conclusions This nonhuman primate model of foveoschisis reveals insights into how acquired myopic traction leads to phenotypically similar morphologic and cellular changes as congenital XLRS without alterations in RS1.
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Affiliation(s)
- Tzu-Ni Sin
- Department of Ophthalmology & Vision Science, University of California Davis, Davis, California, United States
| | - Sangbae Kim
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States
| | - Yumei Li
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States
| | - Jun Wang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States
| | - Rui Chen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States
| | - Sook Hyun Chung
- Department of Ophthalmology & Vision Science, University of California Davis, Davis, California, United States
| | - Soohyun Kim
- Department of Ophthalmology & Vision Science, University of California Davis, Davis, California, United States
- Department of Surgical & Radiological Sciences, University of California Davis, Davis, California, United States
| | - M. Isabel Casanova
- Department of Ophthalmology & Vision Science, University of California Davis, Davis, California, United States
- Department of Surgical & Radiological Sciences, University of California Davis, Davis, California, United States
| | - Sangwan Park
- Department of Ophthalmology & Vision Science, University of California Davis, Davis, California, United States
- Department of Surgical & Radiological Sciences, University of California Davis, Davis, California, United States
| | - Zeljka Smit-McBride
- Department of Ophthalmology & Vision Science, University of California Davis, Davis, California, United States
| | - Ning Sun
- Department of Ophthalmology & Vision Science, University of California Davis, Davis, California, United States
| | - Ori Pomerantz
- California National Primate Research Center, Davis, California, United States
| | - Jeffrey A. Roberts
- California National Primate Research Center, Davis, California, United States
| | - Bin Guan
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Robert B. Hufnagel
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Ala Moshiri
- Department of Ophthalmology & Vision Science, University of California Davis, Davis, California, United States
| | - Sara M. Thomasy
- Department of Ophthalmology & Vision Science, University of California Davis, Davis, California, United States
- Department of Surgical & Radiological Sciences, University of California Davis, Davis, California, United States
| | - Paul A. Sieving
- Department of Ophthalmology & Vision Science, University of California Davis, Davis, California, United States
| | - Glenn Yiu
- Department of Ophthalmology & Vision Science, University of California Davis, Davis, California, United States
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Smit-McBride Z, Morse LS. MicroRNA and diabetic retinopathy-biomarkers and novel therapeutics. Ann Transl Med 2021; 9:1280. [PMID: 34532417 PMCID: PMC8421969 DOI: 10.21037/atm-20-5189] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 01/14/2021] [Indexed: 01/10/2023]
Abstract
Diabetic retinopathy (DR) accounts for ~80% of legal blindness in persons aged 20-74 years and is associated with enormous social and health burdens. Current therapies are invasive, non-curative, and in-effective in 15-25% of DR patients. This review outlines the potential utility of microRNAs (miRNAs) as biomarkers and potential therapy for diabetic retinopathy. miRNAs are small noncoding forms of RNA that may play a role in the pathogenesis of DR by altering the level of expression of genes via single nucleotide polymorphism and regulatory loops. A majority of miRNAs are intracellular and specific intracellular microRNAs have been associated with cellular changes associated with DR. Some microRNAs are extracellular and called circulatory microRNAs. Circulatory miRNAs have been found to be differentially expressed in serum and bodily fluid in patients with diabetes mellitus (DM) with and without retinopathy. Some miRNAs have been associated with the severity of DR, and future studies may reveal whether circulatory miRNAs could serve as novel reliable biomarkers to detect or predict retinopathy progression. Therapeutic strategies can be developed utilizing the natural miRNA/long noncoding RNA (lncRNA) regulatory loops. miRNAs and lncRNAs are two major families of the non-protein-coding transcripts. They are regulatory molecules for fundamental cellular processes via a variety of mechanisms, and their expression and function are tightly regulated. The recent evidence indicates a cross-talk between miRNAs and lncRNAs. Therefore, dysregulation of miRNAs and lncRNAs is critical to human disease pathogenesis, such as diabetic retinopathy. miRNAs are long-distance communicators and reprogramming agents, and they embody an entirely novel paradigm in cellular and tissue signaling and interaction. By targeting specific miRNAs, whole pathways implicated in the pathogenesis of DR may potentially be altered. Understanding the endogenous roles of miRNAs in the pathogenesis of diabetic retinopathy could lead to novel diagnostic and therapeutic approaches to managing this frequently blinding retinal condition.
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Affiliation(s)
- Zeljka Smit-McBride
- Department of Ophthalmology & Vision Science, Vitreoretinal Research Laboratory, School of Medicine, University of California Davis, Davis, California, USA
| | - Lawrence S Morse
- Department of Ophthalmology & Vision Science, Vitreoretinal Research Laboratory, School of Medicine, University of California Davis, Davis, California, USA
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Smit-McBride Z, Nguyen AT, Yu AK, Modjtahedi SP, Hunter AA, Rashid S, Moisseiev E, Morse LS. Unique molecular signatures of microRNAs in ocular fluids and plasma in diabetic retinopathy. PLoS One 2020; 15:e0235541. [PMID: 32692745 PMCID: PMC7373301 DOI: 10.1371/journal.pone.0235541] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Accepted: 06/18/2020] [Indexed: 12/13/2022] Open
Abstract
The main objective of this pilot study was to identify circulatory microRNAs in aqueous or plasma that were reflecting changes in vitreous of diabetic retinopathy patients. Aqueous, vitreous and plasma samples were collected from a total of 27 patients undergoing vitreoretinal surgery: 11 controls (macular pucker or macular hole patients) and 16 with diabetes mellitus(DM): DM-Type I with proliferative diabetic retinopathy(PDR) (DMI-PDR), DM Type II with PDR(DMII-PDR) and DM Type II with nonproliferative DR(DMII-NPDR). MicroRNAs were isolated using Qiagen microRNeasy kit, quantified on BioAnalyzer, and profiled on Affymetrix GeneChip miRNA 3.0 microarrays. Data were analyzed using Expression Console, Transcriptome Analysis Console, and Ingenuity Pathway Analysis. The comparison analysis of circulatory microRNAs showed that out of a total of 847 human microRNA probes on the microarrays, common microRNAs present both in aqueous and vitreous were identified, and a large number of unique microRNA, dependent on the DM type and severity of retinopathy. Most of the dysregulated microRNAs in aqueous and vitreous of DM patients were upregulated, while in plasma, they were downregulated. Dysregulation of miRNAs in aqueous did not appear to be a good representative of the miRNA abundance in vitreous, or plasma, although a few potential candidates for common biomarkers stood out: let-7b, miR-320b, miR-762 and miR-4488. Additionally, each of the DR subtypes showed miRNAs that were uniquely dysregulated in each fluid (i.e. aqueous: for DMII-NPDR was miR-455-3p; for DMII-PDR was miR-296, and for DMI-PDR it was miR-3202). Pathway analysis identified TGF-beta and VEGF pathways affected. The comparative profiling of circulatory miRNAs showed that a small number of them displayed differential presence in diabetic retinopathy vs. controls. A pattern is emerging of unique molecular microRNA signatures in bodily fluids of DR subtypes, offering promise for the use of ocular fluids and plasma for diagnostic and therapeutic purposes.
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Affiliation(s)
- Zeljka Smit-McBride
- Department of Ophthalmology & Vision Science, Vitreoretinal Research Laboratory, School of Medicine, University of California Davis, Davis, California, United States of America
- * E-mail:
| | - Anthony T. Nguyen
- Department of Ophthalmology & Vision Science, Vitreoretinal Research Laboratory, School of Medicine, University of California Davis, Davis, California, United States of America
| | - Alfred K. Yu
- Department of Ophthalmology & Vision Science, Vitreoretinal Research Laboratory, School of Medicine, University of California Davis, Davis, California, United States of America
| | - Sara P. Modjtahedi
- Department of Ophthalmology & Vision Science, Vitreoretinal Research Laboratory, School of Medicine, University of California Davis, Davis, California, United States of America
| | - Allan A. Hunter
- Department of Ophthalmology & Vision Science, Vitreoretinal Research Laboratory, School of Medicine, University of California Davis, Davis, California, United States of America
| | - Saadia Rashid
- Department of Ophthalmology & Vision Science, Vitreoretinal Research Laboratory, School of Medicine, University of California Davis, Davis, California, United States of America
| | - Elad Moisseiev
- Department of Ophthalmology & Vision Science, Vitreoretinal Research Laboratory, School of Medicine, University of California Davis, Davis, California, United States of America
| | - Lawrence S. Morse
- Department of Ophthalmology & Vision Science, Vitreoretinal Research Laboratory, School of Medicine, University of California Davis, Davis, California, United States of America
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Moisseiev E, Smit-McBride Z, Oltjen S, Zhang P, Zawadzki RJ, Motta M, Murphy CJ, Cary W, Annett G, Nolta JA, Park SS. Intravitreal Administration of Human Bone Marrow CD34+ Stem Cells in a Murine Model of Retinal Degeneration. Invest Ophthalmol Vis Sci 2017; 57:4125-35. [PMID: 27537262 PMCID: PMC6733500 DOI: 10.1167/iovs.16-19252] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Purpose Intravitreal murine lineage-negative bone marrow (BM) hematopoietic cells slow down retinal degeneration. Because human BM CD34+ hematopoietic cells are not precisely comparable to murine cells, this study examined the effect of intravitreal human BM CD34+ cells on the degenerating retina using a murine model. Methods C3H/HeJrd1/rd1 mice, immunosuppressed systemically with tacrolimus and rapamycin, were injected intravitreally with PBS (n = 16) or CD34+ cells (n = 16) isolated from human BM using a magnetic cell sorter and labeled with enhanced green fluorescent protein (EGFP). After 1 and 4 weeks, the injected eyes were imaged with scanning laser ophthalmoscopy (SLO)/optical coherence tomography (OCT) and tested with electroretinography (ERG). Eyes were harvested after euthanasia for immunohistochemical and microarray analysis of the retina. Results In vivo SLO fundus imaging visualized EGFP-labeled cells within the eyes following intravitreal injection. Simultaneous OCT analysis localized the EGFP-labeled cells on the retinal surface resulting in a saw-toothed appearance. Immunohistochemical analysis of the retina identified EGFP-labeled cells on the retinal surface and adjacent to ganglion cells. Electroretinography testing showed a flat signal both at 1 and 4 weeks following injection in all eyes. Microarray analysis of the retina following cell injection showed altered expression of more than 300 mouse genes, predominantly those regulating photoreceptor function and maintenance and apoptosis. Conclusions Intravitreal human BM CD34+ cells rapidly home to the degenerating retinal surface. Although a functional benefit of this cell therapy was not seen on ERG in this rapidly progressive retinal degeneration model, molecular changes in the retina associated with CD34+ cell therapy suggest potential trophic regenerative effects that warrant further exploration.
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Affiliation(s)
- Elad Moisseiev
- Department of Ophthalmology & Vision Science University of California Davis Eye Center, Sacramento, California, United States 2Department of Ophthalmology, Tel Aviv Medical Center, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Zeljka Smit-McBride
- Vitreoretinal Research Laboratory, University of California Davis Department of Ophthalmology, University of California, Davis, California, United States
| | - Sharon Oltjen
- Vitreoretinal Research Laboratory, University of California Davis Department of Ophthalmology, University of California, Davis, California, United States
| | - Pengfei Zhang
- University of California Davis Research Investments in the Sciences and Engineering (RISE) Eye-Pod Laboratory, Department of Cell Biology and Human Anatomy, University of California, Davis, California, United States
| | - Robert J Zawadzki
- Department of Ophthalmology & Vision Science University of California Davis Eye Center, Sacramento, California, United States 4University of California Davis Research Investments in the Sciences and Engineering (RISE) Eye-Pod Laboratory, Department of Cel
| | - Monica Motta
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, California, United States
| | - Christopher J Murphy
- Department of Ophthalmology & Vision Science University of California Davis Eye Center, Sacramento, California, United States 5Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, California, Un
| | - Whitney Cary
- Stem Cell Program, Institute for Regenerative Cures, University of California Davis Medical Center, Sacramento, California, United States
| | - Geralyn Annett
- Stem Cell Program, Institute for Regenerative Cures, University of California Davis Medical Center, Sacramento, California, United States
| | - Jan A Nolta
- Stem Cell Program, Institute for Regenerative Cures, University of California Davis Medical Center, Sacramento, California, United States
| | - Susanna S Park
- Department of Ophthalmology & Vision Science University of California Davis Eye Center, Sacramento, California, United States
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Yiu G, Tieu E, Nguyen AT, Wong B, Smit-McBride Z. Genomic Disruption of VEGF-A Expression in Human Retinal Pigment Epithelial Cells Using CRISPR-Cas9 Endonuclease. Invest Ophthalmol Vis Sci 2016; 57:5490-5497. [PMID: 27768202 PMCID: PMC5072539 DOI: 10.1167/iovs.16-20296] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 09/18/2016] [Indexed: 12/26/2022] Open
Abstract
PURPOSE To employ type II clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 endonuclease to suppress ocular angiogenesis by genomic disruption of VEGF-A in human RPE cells. METHODS CRISPR sequences targeting exon 1 of human VEGF-A were computationally identified based on predicted Cas9 on- and off-target probabilities. Single guide RNA (gRNA) cassettes with these target sequences were cloned into lentiviral vectors encoding the Streptococcuspyogenes Cas9 endonuclease (SpCas9) gene. The lentiviral vectors were used to infect ARPE-19 cells, a human RPE cell line. Frequency of insertion or deletion (indel) mutations was assessed by T7 endonuclease 1 mismatch detection assay; mRNA levels were assessed with quantitative real-time PCR; and VEGF-A protein levels were determined by ELISA. In vitro angiogenesis was measured using an endothelial cell tube formation assay. RESULTS Five gRNAs targeting VEGF-A were selected based on the highest predicted on-target probabilities, lowest off-target probabilities, or combined average of both scores. Lentiviral delivery of the top-scoring gRNAs with SpCas9 resulted in indel formation in the VEGF-A gene at frequencies up to 37.0% ± 4.0% with corresponding decreases in secreted VEGF-A protein up to 41.2% ± 7.4% (P < 0.001), and reduction of endothelial tube formation up to 39.4% ± 9.8% (P = 0.02). No significant indel formation in the top three putative off-target sites tested was detected. CONCLUSIONS The CRISPR-Cas9 endonuclease system may reduce VEGF-A secretion from human RPE cells and suppress angiogenesis, supporting the possibility of employing gene editing for antiangiogenesis therapy in ocular diseases.
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Affiliation(s)
- Glenn Yiu
- Department of Ophthalmology & Vision Science, University of California, Davis, Sacramento, California, United States
| | - Eric Tieu
- Department of Ophthalmology & Vision Science, University of California, Davis, Sacramento, California, United States
| | - Anthony T. Nguyen
- Department of Ophthalmology & Vision Science, University of California, Davis, Sacramento, California, United States
| | - Brittany Wong
- Duke University, Durham, North Carolina, United States
| | - Zeljka Smit-McBride
- Department of Ophthalmology & Vision Science, University of California, Davis, Sacramento, California, United States
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Hunter AA, Smit-McBride Z, Anderson R, Bordbari MH, Ying GS, Kim ES, Park SS, Telander DG, Dunaief JL, Hjelmeland LM, Morse LS. GSTM1 and GSTM5 Genetic Polymorphisms and Expression in Age-Related Macular Degeneration. Curr Eye Res 2015; 41:410-6. [PMID: 25897651 DOI: 10.3109/02713683.2015.1016179] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
PURPOSE Previously, two cytosolic antioxidant enzymes, Glutathione S-transferase Mu 1 (GSTM1) and Mu 5 (GSTM5), were reduced in retinas with age-related macular degeneration (AMD). This study compared genomic copy number variations (gCNV) of these two antioxidant enzymes in AMD versus controls. METHODS Genomic copy number (gCN) assays were performed using Taqman Gene Copy Number Assays (Applied Biosystems, Darmstadt, Germany) in technical quadruplicate for both GSTM1 and GSTM5. Peripheral leukocyte RNA levels were compared with controls in technical triplicates. Statistical comparisons were performed in SAS v9.2 (SAS Institute Inc., Cary, NC). RESULTS A large percentage of patients in both AMD and age-matched control groups had no copies of GSTM1 (0/0). The mean gCN of GSTM1 was 1.40 (range 0-4) and 1.61 (range 0-5) for AMD and control, respectively (p = 0.29). A greater percentage of control patients had > 3 gCNs of GSTM1 compared with AMD, respectively (15.3% versus 3.0%, p = 0.004). The gCN of GSTM5 was 2 in all samples except one control sample. The relative quantification of GSTM1 and GSTM5 mRNA from peripheral blood leukocytes in patients showed significant differences in relative expression in AMD versus control (p < 0.05). Peripheral blood leukocyte mRNA and gCN were not significantly correlated (p = 0.27). CONCLUSION Since high copy numbers of GSTM1 are found more frequently in controls than in AMD, it is possible that high copy number leads to increased retinal antioxidant defense. Genomic polymorphisms of GSTM1 and GSTM5 do not significantly affect the peripheral blood leukocyte mRNA levels.
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Affiliation(s)
- Allan A Hunter
- a Department of Ophthalmology & Vision Science , University of California Davis Eye Center , Sacramento , CA , USA and
| | - Zeljka Smit-McBride
- a Department of Ophthalmology & Vision Science , University of California Davis Eye Center , Sacramento , CA , USA and
| | - Rachel Anderson
- a Department of Ophthalmology & Vision Science , University of California Davis Eye Center , Sacramento , CA , USA and
| | - Matthew H Bordbari
- a Department of Ophthalmology & Vision Science , University of California Davis Eye Center , Sacramento , CA , USA and
| | - Gui-shuang Ying
- b FM Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania , Philadelphia , PA , USA
| | - Esther S Kim
- a Department of Ophthalmology & Vision Science , University of California Davis Eye Center , Sacramento , CA , USA and
| | - Susanna S Park
- a Department of Ophthalmology & Vision Science , University of California Davis Eye Center , Sacramento , CA , USA and
| | - David G Telander
- a Department of Ophthalmology & Vision Science , University of California Davis Eye Center , Sacramento , CA , USA and
| | - Joshua L Dunaief
- b FM Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania , Philadelphia , PA , USA
| | - Leonard M Hjelmeland
- a Department of Ophthalmology & Vision Science , University of California Davis Eye Center , Sacramento , CA , USA and
| | - Lawrence S Morse
- a Department of Ophthalmology & Vision Science , University of California Davis Eye Center , Sacramento , CA , USA and
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Smit-McBride Z, Oltjen SL, Radu RA, Estep J, Nguyen AT, Gong Q, Hjelmeland LM. Localization of complement factor H gene expression and protein distribution in the mouse outer retina. Mol Vis 2015; 21:110-23. [PMID: 25684976 PMCID: PMC4323684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 02/03/2015] [Indexed: 11/28/2022] Open
Abstract
PURPOSE To determine the localization of complement factor H (Cfh) mRNA and its protein in the mouse outer retina. METHODS Quantitative real-time PCR (qPCR) was used to determine the expression of Cfh and Cfh-related (Cfhr) transcripts in the RPE/choroid. In situ hybridization (ISH) was performed using the novel RNAscope 2.0 FFPE assay to localize the expression of Cfh mRNA in the mouse outer retina. Immunohistochemistry (IHC) was used to localize Cfh protein expression, and western blots were used to characterize CFH antibodies used for IHC. RESULTS Cfh and Cfhr2 transcripts were detected in the mouse RPE/choroid using qPCR, while Cfhr1, Cfhr3, and Cfhrc (Gm4788) were not detected. ISH showed abundant Cfh mRNA in the RPE of all mouse strains (C57BL/6, BALB/c, 129/Sv) tested, with the exception of the Cfh(-/-) eye. Surprisingly, the Cfh protein was detected by immunohistochemistry in photoreceptors rather than in RPE cells. The specificity of the CFH antibodies was tested by western blotting. Our CFH antibodies recognized purified mouse Cfh protein, serum Cfh protein in wild-type C57BL/6, BALB/c, and 129/Sv, and showed an absence of the Cfh protein in the serum of Cfh(-/-) mice. Greatly reduced Cfh protein immunohistological signals in the Cfh(-/-) eyes also supported the specificity of the Cfh protein distribution results. CONCLUSIONS Only Cfh and Cfhr2 genes are expressed in the mouse outer retina. Only Cfh mRNA was detected in the RPE, but no protein. We hypothesize that the steady-state concentration of Cfh protein is low in the cells due to secretion, and therefore is below the detection level for IHC.
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Affiliation(s)
| | - Sharon L. Oltjen
- Department of Ophthalmology, University of California, Davis, CA
| | - Roxana A. Radu
- Jules Stein Eye Institute, University of California, Los Angeles, CA
| | - Jason Estep
- Department of Human Anatomy and Cell Biology, University of California, Davis, CA
| | | | - Qizhi Gong
- Department of Human Anatomy and Cell Biology, University of California, Davis, CA
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Smit-McBride Z, Forward KI, Nguyen AT, Bordbari MH, Oltjen SL, Hjelmeland LM. Age-dependent increase in miRNA-34a expression in the posterior pole of the mouse eye. Mol Vis 2014; 20:1569-78. [PMID: 25489229 PMCID: PMC4225137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 11/03/2014] [Indexed: 10/26/2022] Open
Abstract
PURPOSE MicroRNA-34a (miR-34a) has been implicated in neurodegeneration. MiR-34a belongs to a signaling network involving p53 and Sirt-1. This network responds to DNA damage with further downstream signals that induce senescence or apoptosis. Our goal was to measure the expression level of miR-34a in the mouse retina and RPE as a function of age. METHODS The age-dependent change in miR-34a expression was quantified using a real-time PCR (RT-PCR) assay on microRNA isolates from eye tissue: the retina and RPE/choroid (4, 18, 24, and 32 months of age). Tissue localization of miR-34a was determined by in situ hybridization (ISH) for a series of time points. Expression of the miR-34a target gene Sirt1 was analyzed using RT-PCR and immunohistochemistry. RESULTS MiR-34a examined with real-time PCR showed a linear increase in expression with age when compared to that of 4-month-old mice. However, the level of expression between the 24 and 32-month-old animals showed mild downregulation. An age-related increase in miR-34a expression was confirmed in the mouse eye using in situ hybridization. An inverse relationship between the levels of expression of miR-34a and its target Sirt1 mRNA was found at 18 and 24 months of age. CONCLUSIONS Our data showed that miR-34a expression increased in the retina and RPE with age. The level of DNA damage in mitochondria in the retina and RPE followed a similar time course. This suggests that miR-34a may play a role in the senescence and apoptosis of the retina and RPE cells in the aging eye.
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Verhoeven D, George MD, Hu W, Dang AT, Smit-McBride Z, Reay E, Macal M, Fenton A, Sankaran-Walters S, Dandekar S. Enhanced innate antiviral gene expression, IFN-α, and cytolytic responses are predictive of mucosal immune recovery during simian immunodeficiency virus infection. J Immunol 2014; 192:3308-18. [PMID: 24610016 DOI: 10.4049/jimmunol.1302415] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The mucosa that lines the respiratory and gastrointestinal (GI) tracts is an important portal of entry for pathogens and provides the first line of innate immune defense against infections. Although an abundance of memory CD4(+) T cells at mucosal sites render them highly susceptible to HIV infection, the gut and not the lung experiences severe and sustained CD4(+) T cell depletion and tissue disruption. We hypothesized that distinct immune responses in the lung and gut during the primary and chronic stages of viral infection contribute to these differences. Using the SIV model of AIDS, we performed a comparative analysis of the molecular and cellular characteristics of host responses in the gut and lung. Our findings showed that both mucosal compartments harbor similar percentages of memory CD4(+) T cells and displayed comparable cytokine (IL-2, IFN-γ, and TNF-α) responses to mitogenic stimulations prior to infection. However, despite similar viral replication and CD4(+) T cell depletion during primary SIV infection, CD4(+) T cell restoration kinetics in the lung and gut diverged during acute viral infection. The CD4(+) T cells rebounded or were preserved in the lung mucosa during chronic viral infection, which correlated with heightened induction of type I IFN signaling molecules and innate viral restriction factors. In contrast, the lack of CD4(+) T cell restoration in the gut was associated with dampened immune responses and diminished expression of viral restriction factors. Thus, unique immune mechanisms contribute to the differential response and protection of pulmonary versus GI mucosa and can be leveraged to enhance mucosal recovery.
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Affiliation(s)
- David Verhoeven
- Department of Medical Microbiology and Immunology, University of California, Davis, Davis, CA 95616
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Abstract
Evolutionary theories of aging predict the existence of certain genes that provide selective advantage early in life with adverse effect on lifespan later in life (antagonistic pleiotropy theory) or longevity insurance genes (disposable soma theory). Indeed, the study of human and animal genetics is gradually identifying new genes that increase lifespan when overexpressed or mutated: gerontogenes. Furthermore, genetic and epigenetic mechanisms are being identified that have a positive effect on longevity. The gerontogenes are classified as lifespan regulators, mediators, effectors, housekeeping genes, genes involved in mitochondrial function, and genes regulating cellular senescence and apoptosis. In this review we demonstrate that the majority of the genes as well as genetic and epigenetic mechanisms that are involved in regulation of longevity are highly interconnected and related to stress response.
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Affiliation(s)
- Alexey A Moskalev
- Moscow Institute of Physics and Technology; Moscow, Russian Federation; Institute of Biology; Komi Science Center of Russian Academy of Sciences; Syktyvkar, Russian Federation; Syktyvkar State University; Syktyvkar, Russian Federation
| | - Alexander M Aliper
- Moscow Institute of Physics and Technology; Moscow, Russian Federation; Institute of Biology; Komi Science Center of Russian Academy of Sciences; Syktyvkar, Russian Federation
| | - Zeljka Smit-McBride
- Department of Ophthalmology and Vision Science; School of Medicine; University of California at Davis; Davis, CA USA
| | - Anton Buzdin
- Moscow Institute of Physics and Technology; Moscow, Russian Federation; Federal Clinical Research Center of Pediatric Hematology, Oncology, and Immunology; Moscow, Russian Federation; Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry; Moscow, Russian Federation; First Oncology Research and Advisory Center; Moscow, Russian Federation
| | - Alex Zhavoronkov
- Moscow Institute of Physics and Technology; Moscow, Russian Federation; Federal Clinical Research Center of Pediatric Hematology, Oncology, and Immunology; Moscow, Russian Federation; The Biogerontology Research Foundation; London, UK
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Zhavoronkov A, Smit-McBride Z, Guinan KJ, Litovchenko M, Moskalev A. Potential therapeutic approaches for modulating expression and accumulation of defective lamin A in laminopathies and age-related diseases. J Mol Med (Berl) 2012; 90:1361-89. [PMID: 23090008 PMCID: PMC3506837 DOI: 10.1007/s00109-012-0962-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2012] [Revised: 09/08/2012] [Accepted: 09/25/2012] [Indexed: 01/28/2023]
Abstract
Scientific understanding of the genetic components of aging has increased in recent years, with several genes being identified as playing roles in the aging process and, potentially, longevity. In particular, genes encoding components of the nuclear lamina in eukaryotes have been increasingly well characterized, owing in part to their clinical significance in age-related diseases. This review focuses on one such gene, which encodes lamin A, a key component of the nuclear lamina. Genetic variation in this gene can give rise to lethal, early-onset diseases known as laminopathies. Here, we analyze the literature and conduct computational analyses of lamin A signaling and intracellular interactions in order to examine potential mechanisms for altering or slowing down aberrant Lamin A expression and/or for restoring the ratio of normal to aberrant lamin A. The ultimate goal of such studies is to ameliorate or combat laminopathies and related diseases of aging, and we provide a discussion of current approaches in this review.
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Affiliation(s)
- Alex Zhavoronkov
- Bioinformatics and Medical Information Technology Laboratory, Center for Pediatric Hematology, Oncology and Immunology, Moscow, 119296 Russia
- The Biogerontology Research Foundation, Reading, UK
| | - Zeljka Smit-McBride
- Department of Ophthalmology and Vision Science, School of Medicine, University of California at Davis, Davis, CA 95616 USA
| | - Kieran J. Guinan
- The Biogerontology Research Foundation, Reading, UK
- BioAtlantis Ltd., Kerry Technology Park, Tralee, County Kerry Ireland
| | - Maria Litovchenko
- Bioinformatics and Medical Information Technology Laboratory, Center for Pediatric Hematology, Oncology and Immunology, Moscow, 119296 Russia
| | - Alexey Moskalev
- The Biogerontology Research Foundation, Reading, UK
- Laboratory of Molecular Radiobiology and Gerontology, Institute of Biology, Komi Science Center of Russian Academy of Sciences, Syktyvkar, 167982 Russia
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Moskalev AA, Smit-McBride Z, Shaposhnikov MV, Plyusnina EN, Zhavoronkov A, Budovsky A, Tacutu R, Fraifeld VE. Gadd45 proteins: relevance to aging, longevity and age-related pathologies. Ageing Res Rev 2012; 11:51-66. [PMID: 21986581 PMCID: PMC3765067 DOI: 10.1016/j.arr.2011.09.003] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Revised: 09/25/2011] [Accepted: 09/27/2011] [Indexed: 12/12/2022]
Abstract
The Gadd45 proteins have been intensively studied, in view of their important role in key cellular processes. Indeed, the Gadd45 proteins stand at the crossroad of the cell fates by controlling the balance between cell (DNA) repair, eliminating (apoptosis) or preventing the expansion of potentially dangerous cells (cell cycle arrest, cellular senescence), and maintaining the stem cell pool. However, the biogerontological aspects have not thus far received sufficient attention. Here we analyzed the pathways and modes of action by which Gadd45 members are involved in aging, longevity and age-related diseases. Because of their pleiotropic action, a decreased inducibility of Gadd45 members may have far-reaching consequences including genome instability, accumulation of DNA damage, and disorders in cellular homeostasis - all of which may eventually contribute to the aging process and age-related disorders (promotion of tumorigenesis, immune disorders, insulin resistance and reduced responsiveness to stress). Most recently, the dGadd45 gene has been identified as a longevity regulator in Drosophila. Although further wide-scale research is warranted, it is becoming increasingly clear that Gadd45s are highly relevant to aging, age-related diseases (ARDs) and to the control of life span, suggesting them as potential therapeutic targets in ARDs and pro-longevity interventions.
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Affiliation(s)
- Alexey A Moskalev
- Group of Molecular Radiobiology and Gerontology, Institute of Biology, Komi Science Center of Russian Academy of Sciences.
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13
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Smit-McBride Z, Modjtahedi SP, Cessna CT, Telander DG, Hjelmeland LM, Morse LS. In vivo gene expression profiling of retina postintravitreal injections of dexamethasone and triamcinolone at clinically relevant time points for patient care. Invest Ophthalmol Vis Sci 2011; 52:8965-78. [PMID: 21873667 DOI: 10.1167/iovs.10-7084] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To identify retinal genes and their relevant expression pathways affected by intravitreal injections of dexamethasone (Dex) and triamcinolone acetonide (TAA) in mice at clinically relevant time points for patient care. METHODS Differential gene expressions of over 34,000 well-characterized mouse genes, in the retinas of 6-week-old C57BL/6J mice, were analyzed after intravitreal steroid injections at 1 week and 1 month time points, using mouse genome microarrays. The data were analyzed using commercial microarray analysis software for biologically relevant changes in gene expression pathways. RESULTS A common gene pathway, with differentially activated genes for both steroids and time points, was "Semaphorin Signaling in Neurons," a member of the "Axonal Guidance Signaling System." At 1 week postinjection a common theme was activation of genes expressed in retinal glial cells, tumor necrosis factor-α, and transforming growth factor-β signaling pathways and upregulation of stress response proteins (Serpina3n, Cebpd), as well as neuropeptide signaling somatostatin receptor (Sstr2). Unique for Dex was the upregulation of acute phase proteins (Gfap, Cp, Edn2) as well as Plexna2, a semaphorin signaling receptor, whereas EphrinB receptor ephexin 1 (Argef15) was downregulated. Folate signaling appears to be unique for TAA at 1 week (Folh1, Cubn), whereas aryl-hydrocarbon receptor signaling might be important for both steroids at 1 month postinjection. CONCLUSIONS Understanding the molecular and genetic effects of intraocular steroid treatments is of clinical relevance. This in vivo study has elucidated several genes and pathways that are potentially altering the neuroprotective/neurodegenerative balance between glial and retinal ganglion cells during intravitreal steroid treatment.
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Affiliation(s)
- Zeljka Smit-McBride
- Vitreoretinal Research Laboratory, Department of Ophthalmology, University of California Davis, Davis, California, USA
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14
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Hjelmeland LM, Fujikawa A, Oltjen SL, Smit-McBride Z, Braunschweig D. Quantification of retinal pigment epithelial phenotypic variation using laser scanning cytometry. Mol Vis 2010; 16:1108-21. [PMID: 20606706 PMCID: PMC2893051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2009] [Accepted: 06/10/2010] [Indexed: 12/03/2022] Open
Abstract
PURPOSE Quantifying phenotypic variation at the level of protein expression (variegation) within populations of retinal pigment epithelium (RPE) cells may be important in the study of pathologies associated with this variation. The lack of quantitative methods for examining single cells, however, and the variable presence of pigment and/or lipofuscin complicate this experimental goal. We have applied the technique of laser scanning cytometry (LSC) to paraffin sections of mouse and human eyes to evaluate the utility of LSC for these measurements. METHODS Mouse eyes were perfusion fixed in 4% paraformaldehyde and embedded in paraffin. Postmortem human eyes were fixed and dissected to obtain a 9-mm punch, which was then embedded in paraffin. A laser scanning cytometer equipped with violet, argon, and helium-neon lasers and the detectors for blue, green, and long red were used to record the fluorescence of each individual cell at all three wavelengths. Raw data were recorded and processed using the WinCyte software. Individual nuclei were identified by the fluorescence of the 4',6-diamidino-2-phenylindole (DAPI) nuclear counterstain. Next, RPE cells were uniquely identified in the green channel using an anti-retinal pigment epithelium-specific protein 65 kDa (anti-RPE65) monoclonal antibody with an Alexa Fluor 488-labeled secondary antibody. Mn-superoxide dismutase (MnSOD) was quantified in the long-red channel using an anti-MnSOD antibody and an Alexa Fluor 647-labeled secondary antibody. MnSOD(+) and RPE65(+) cells exhibited peaks in the plot of fluorescence intensity versus cell number, which could be characterized by the mean fluorescence intensity (MFI), the coefficient of variation (CV), and the percentage of total RPE cells that were also labeled for MnSOD. RESULTS RPE cells can be uniquely identified in human and mouse paraffin sections by immunolabeling with anti-RPE65 antibody. A second antigen, such as MnSOD, can then be probed only within this set of RPE. Results are plotted primarily with the population frequency diagram, which can be subdivided into multiple regions. The data collected for each region include the MFI, the CV, and the number of cells that are immunolabeled in that region. Background interference from pigment or autofluorescent material can be successfully overcome by elevating the concentrations of fluorescent secondary antibodies. In the human and mouse eyes, age-related changes in MFI, CV, and percent RPE cells immunolabeled for MnSOD were observed. CONCLUSIONS The extent of the variability of gene expression in RPE cells at the protein level can be quantified by LSC. Relative changes in the MFI, the CV, and/or percentage of RPE cells double labeled for a second antigen quantify the changes observed. The analysis of these data also suggest whether the effects observed are related to local changes in transcription (alterations of CV) or major changes of protein expression (MFI), which are likely to be due to changes in the chromatin structure. The changes of these variables with age suggest that the observed age-related variegation is primarily due to changes in the chromatin structure in individual cells.
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Affiliation(s)
- L M Hjelmeland
- Department of Ophthalmology, School of Medicine, University of California at Davis, Davis, CA 95616, USA.
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15
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Zhang L, Smit-McBride Z, Pan X, Rheinhardt J, Hershey JWB. An oncogenic role for the phosphorylated h-subunit of human translation initiation factor eIF3. J Biol Chem 2008; 283:24047-60. [PMID: 18544531 DOI: 10.1074/jbc.m800956200] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Dysregulation of protein synthesis has been implicated in oncogenesis through a mechanism whereby "weak" mRNAs encoding proteins involved in cell proliferation are strongly translated when the protein synthesis apparatus is activated. Previous work has determined that many cancer cells contain high levels of eIF3h, a protein subunit of translation initiation factor eIF3, and overexpression of eIF3h malignantly transforms immortal NIH-3T3 cells. This is a general feature of eIF3h, as high levels also affect translation, proliferation, and a number of malignant phenotypes of CHO-K1 and HeLa cells and, most significantly, of a primary prostate cell line. Furthermore, overexpressed eIF3h inhibits Myc-dependent induction of apoptosis of primary prostate cells. eIF3h appears to function through translation, as the initial appearance of overexpressed eIF3h in rapidly induced NIH-3T3 cells correlates tightly with the stimulation of protein synthesis and the generation of malignant phenotypes. This oncogenic potential of eIF3h is enhanced by phosphorylation at Ser(183). Finally, reduction of eIF3h levels in breast and prostate cancer cell lines by short interfering RNA methods reduces their rates of proliferation and anchorage-independent growth in soft agar. The results provide compelling evidence that high eIF3h levels directly stimulate protein synthesis, resulting in the establishment and maintenance of the malignant state in cells.
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Affiliation(s)
- Lili Zhang
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California-Davis, CA 95616, USA
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16
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Smit-McBride Z, Oltjen SL, Lavail MM, Hjelmeland LM. A Strong Genetic Determinant of Hyperoxia-Related Retinal Degeneration on Mouse Chromosome 6. ACTA ACUST UNITED AC 2007; 48:405-11. [PMID: 17197561 DOI: 10.1167/iovs.06-0854] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
PURPOSE Hyperoxia-related retinal degeneration (HRRD) is a model system in the mouse in which elevated oxygen levels are used to induce retinal degeneration. The hypothesis for the present study was that strain differences in HRRD susceptibility are due to allelic variants of one or more genes in the mouse genome whose human orthologues should be important targets for research and drug development. METHODS C57BL/6J, A/J, or B.A-Chr6 mice were exposed to 75% oxygen (hyperoxia) or room air for 14 days. After death, one eye was fixed and processed for outer nuclear layer (ONL) thickness measurements. The retina and RPE/choroid were separately dissected from the fellow eye and processed for microarray analysis. Single nucleotide polymorphism (SNP) analysis for transcribed sequences from the C57BL/6J and A/J genomes was conducted using the NIH genome site. RESULTS C57BL/6J mice developed a significant retinal degeneration in the inferior hemisphere after 14 days of hyperoxia. Under identical conditions, A/J mice exhibited only minor changes. A significant genetic effect was located on chromosome 6. SNP analysis of known transcribed sequences on chromosome 6 combined with microarray expression analysis yielded 33 candidate genes. CONCLUSIONS A significant genetic effect of susceptibility to HRRD is located on chromosome 6. In silico analysis of transcribed sequences results in a fairly small number of candidate genes.
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Affiliation(s)
- Zeljka Smit-McBride
- Department of Ophthalmology, Vitreoretinal Research Lab, University of California at Davis, School of Medicine, Davis, California 95616, USA
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17
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Alizadeh P, Smit-McBride Z, Oltjen SL, Hjelmeland LM. Regulation of cysteine cathepsin expression by oxidative stress in the retinal pigment epithelium/choroid of the mouse. Exp Eye Res 2006; 83:679-87. [PMID: 16684524 PMCID: PMC1661778 DOI: 10.1016/j.exer.2006.03.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2005] [Revised: 02/16/2006] [Accepted: 03/14/2006] [Indexed: 11/24/2022]
Abstract
Cystatin C is the major inhibitor of the cysteine cathepsins. Polymorphisms in the cystatin C gene have recently been associated with the risk of developing Age-related Macular Degeneration (AMD). Oxidative stress is also thought to play a key role in the pathogenesis of AMD. We surveyed the retinal pigment epithelium (RPE) and choroid of the C57BL/6J mouse for the expression of the cysteine cathepsins under normoxic and hyperoxic (75% O(2)) conditions. Microarray analysis of RPE/choroid mRNA revealed the expression of cathepsins B and L, as well as cystatin C under all experimental conditions. The microarray results were confirmed by real-time quantitative polymerase chain reaction (PCR). Localization of the mRNA species for cystatin C and cathepsin B, as well as, localization of protein species for cystatin C, cathepsins B and L were performed to evaluate the tissue distribution of these species. Our results indicate that cystatin C is largely synthesized in the RPE and secreted from the basal side. Cathepsin B is the major cysteine protease in the RPE and choroid. The expression of all mRNAs and proteins was elevated by exposure to oxidative stress.
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Affiliation(s)
| | | | | | - Leonard M. Hjelmeland
- * Corresponding author: Leonard M. Hjelmeland,
Professor, , Department of
Ophthalmology, Vitreoretinal Research Lab, University of California, One Shields
Ave. Davis CA 95616, USA, PH: (530) 752-2250, FX: (530) 752-2270
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18
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Ida H, Boylan SA, Weigel AL, Smit-McBride Z, Chao A, Gao J, Buchoff P, Wistow G, Hjelmeland LM. EST analysis of mouse retina and RPE/choroid cDNA libraries. Mol Vis 2004; 10:439-44. [PMID: 15257269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2023] Open
Abstract
PURPOSE cDNA libraries from the mouse retina have recently been reported, but no well characterized library from the retinal pigment epithelium (RPE) or choroid of the mouse has yet appeared in the literature. To complement these libraries and to provide the first mouse RPE/choroid library, we used freshly dissected tissue from adult C57BL/6J mice to construct new retina and RPE/choroid libraries. METHODS Eyes from 100 six to eight week old C57BL/6J mice were dissected in groups of 10. The whole retina and RPE/choroid were isolated individually and then homogenized before RNA isolation. Over 5000 clones each were sequenced from the unamplified and un-normalized retina and RPE/choroid libraries. All sequences were analyzed using GRIST (GRouping and Identification of Sequence Tags), a bioinformatics program for gene identification and clustering. RESULTS The RPE/choroid library contained 3145 clusters with 76% of the clusters representing single clones. Nearly 87% of the clusters corresponded to named genes in GenBank, and 8% of the RPE clusters remain unidentified. The retina library contained 3190 clusters of which 78% represented only one clone. Approximately 85% of the clusters matched sequences in GenBank, and 9% of the clusters remain unidentified. The clones most abundant in each library were all well-known sequences and both libraries contained a number of tissue specific or tissue-enhanced genes. CONCLUSIONS These new libraries should provide a valuable resource for gene discovery and cDNAs for expression analysis and functional studies.
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Affiliation(s)
- Hisashi Ida
- Department of Biological Chemistry and Ophthalmology, University of California, Davis, CA 95616-8794, USA
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Clement PMJ, Henderson CA, Jenkins ZA, Smit-McBride Z, Wolff EC, Hershey JWB, Park MH, Johansson HE. Identification and characterization of eukaryotic initiation factor 5A-2. Eur J Biochem 2003; 270:4254-63. [PMID: 14622290 DOI: 10.1046/j.1432-1033.2003.03806.x] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The phylogenetically conserved eukaryotic translation initiation factor 5A (eIF5A) is the only known cellular protein to contain the post-translationally derived amino acid hypusine [Nepsilon-(4-amino-2-hydroxybutyl)lysine]. Both eIF5A and its hypusine modification are essential for sustained cell proliferation. Normally only one eIF5A protein is expressed in human cells. Recently, we identified a second human EIF5A gene that would encode an isoform (eIF5A-2) of 84% sequence identity. Overexpression of eIF5A-2 mRNA in certain human cancer cells, in contrast to weak normal expression limited to human testis and brain, suggests EIF5A2 as a potential oncogene. However, eIF5A-2 protein has not been described in human or mammalian cells heretofore. Here, we describe the identification of eIF5A-2 protein in human colorectal and ovarian cancer lines, SW-480 and UACC-1598, that overexpress eIF5A-2 mRNAs. Functional characterization of the human isoforms revealed that either human EIF5A gene can complement growth of a yeast strain in which the yeast EIF5A genes were disrupted. This indicates functional similarity of the human isoforms in yeast and suggests that eIF5A-2 has an important role in eukaryotic cell survival similar to that of the ubiquitous eIF5A-1. Detectable structural differences were also noted, including lack of immunological cross-reactivity, formation of different complexes with deoxyhypusine synthase, and Km values (1.5 +/- 0.2 vs. 8.3 +/- 1.4 microm for eIF5A-1 and -2, respectively) as substrates for deoxyhypusine synthase in vitro. These physical characteristics and distinct amino acid sequences in the C-terminal domain together with differences in gene expression patterns imply differentiated, tissue-specific functions of the eIF5A-2 isoform in the mammalian organism and in cancer.
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Affiliation(s)
- Paul M J Clement
- Oral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
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Mattapallil JJ, Smit-McBride Z, Dailey P, Dandekar S. Activated memory CD4(+) T helper cells repopulate the intestine early following antiretroviral therapy of simian immunodeficiency virus-infected rhesus macaques but exhibit a decreased potential to produce interleukin-2. J Virol 1999; 73:6661-9. [PMID: 10400763 PMCID: PMC112750 DOI: 10.1128/jvi.73.8.6661-6669.1999] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Using the simian immunodeficiency virus (SIV)-infected rhesus macaque model, we performed a longitudinal study to determine the effect of antiretroviral therapy on the phenotype and functional potential of CD4(+) T cells repopulating intestinal mucosa in human immunodeficiency virus infection. Severe depletion of CD4(+) and CD4(+) CD8(+) T cells occurred in the intestinal mucosa during primary SIV infection. The majority of these cells were of activated memory phenotype. Phosphonate 9-[2-(phosphomethoxypropyl]adenine (PMPA) treatment led to a moderate suppression of intestinal viral loads and repopulation of intestinal mucosa by predominantly activated memory CD4(+) T-helper cells. This repopulation was independent of the level of viral suppression. Compared to preinfection values, the frequency of naive CD4(+) T cells increased following PMPA therapy, suggesting that new CD4(+) T cells were repopulating the intestinal mucosa. Repopulation by CD4(+) CD8(+) T cells was not observed in either jejunum or colon lamina propria. The majority of CD4(+) T cells repopulating the intestinal mucosa following PMPA therapy were CD29(hi) and CD11ahi. A subset of repopulating intestinal CD4(+) T cells expressed Ki-67 antigen, indicating that local proliferation may play a role in the repopulation process. Although the majority of repopulating CD4(+) T cells in the intestinal mucosa were functionally capable of providing B- and T-cell help, as evidenced by their expression of CD28, these CD4(+) T cells were found to have a reduced capacity to produce interleukin-2 (IL-2) compared to the potential of CD4(+) T cells prior to SIV infection. Persistent viral infection may play a role in suppressing the potential of repopulating CD4(+) T cells to produce IL-2. Hence, successful antiretroviral therapy should aim at complete suppression of viral loads in mucosal lymphoid tissues, such as intestinal mucosa.
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Affiliation(s)
- J J Mattapallil
- Division of Infectious Diseases, Department of Internal Medicine, School of Medicine, University of California, Davis, California, USA
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Ndolo T, Rheinhardt J, Zaragoza M, Smit-McBride Z, Dandekar S. Alterations in RANTES gene expression and T-cell prevalence in intestinal mucosa during pathogenic or nonpathogenic simian immunodeficiency virus infection. Virology 1999; 259:110-8. [PMID: 10364494 DOI: 10.1006/viro.1999.9709] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
RANTES, a beta-chemokine, can suppress human immunodeficiency virus (HIV) as well as simian immunodeficiency virus (SIV) infections in T-lymphocyte cultures in vitro. However, the association of RANTES levels in peripheral blood with viral loads and disease outcome in HIV infection has been inconclusive. SIV-infected rhesus macaques were evaluated to determine whether RANTES gene expression correlated with suppression of viral infection in intestinal lymphoid tissues. Intestinal tissues were obtained from rhesus macaques infected with either pathogenic or nonpathogenic SIVmac variants at various stages of infection (primary acute, asymptomatic, and terminal). We examined the level of SIV infection (in situ hybridization), RANTES expression (quantitative competitive RT-PCR), and T-cell counts (immunohistochemistry). The most pronounced increase in RANTES gene expression in intestinal tissues was observed in primary SIV infection, which correlated with the pathogenicity of the infecting virus and not the tissue viral loads. Our results demonstrated that in contrast to the occurrence of viral suppression by RANTES in vitro, there was no direct correlation between high RANTES gene expression and suppression of viral loads in intestinal lymphoid tissues. Thus RANTES expression in the gut lymphoid tissue may not be a correlate for viral suppression. However, RANTES gene expression in primary SIV infection may be part of early host immune response to viral infection.
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Affiliation(s)
- T Ndolo
- Division of Infectious and Immunologic Diseases, University of California, Davis, California 95616, USA
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22
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Mattapallil JJ, Smit-McBride Z, Dandekar S. Gastrointestinal epithelium is an early extrathymic site for increased prevalence of CD34(+) progenitor cells in contrast to the thymus during primary simian immunodeficiency virus infection. J Virol 1999; 73:4518-23. [PMID: 10196359 PMCID: PMC104348 DOI: 10.1128/jvi.73.5.4518-4523.1999] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The objective of this study was to determine the effects of primary simian immunodeficiency virus (SIV) infection on the prevalence and phenotype of progenitor cells present in the gastrointestinal epithelia of SIV-infected rhesus macaques, a primate model for human immunodeficiency virus pathogenesis. The gastrointestinal epithelium was residence to progenitor cells expressing CD34 antigen, a subset of which also coexpressed Thy-1 and c-kit receptors, suggesting that the CD34(+) population in the intestine comprised a subpopulation of primitive precursors. Following experimental SIVmac251 infection, an early increase in the proportions of CD34(+) Thy-1(+) and CD34(+) c-kit+ progenitor cells was observed in the gastrointestinal epithelium. In contrast, the proportion of CD34(+) cells in the thymus declined during primary SIV infection, which was characterized by a decrease in the frequency of CD34(+) Thy-1(+) progenitor cells. A severe depletion in the frequency of CD4-committed CD34(+) progenitors was observed in the gastrointestinal epithelium 2 weeks after SIV infection which persisted even 4 weeks after infection. A coincident increase in the frequency of CD8- committed CD34(+) progenitor cells was observed during primary SIV infection. These results indicate that in contrast to the primary lymphoid organs such as the thymus, the gastrointestinal epithelium may be an early extrathymic site for the increased prevalence of both primitive and committed CD34(+) progenitor cells. The gastrointestinal epithelium may potentially play an important role in maintaining T-cell homeostasis in the intestinal mucosa during primary SIV infection.
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Affiliation(s)
- J J Mattapallil
- Department of Internal Medicine, Division of Infectious Diseases, School of Medicine, University of California Davis, Davis, California, USA
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Mattapallil JJ, Smit-McBride Z, McChesney M, Dandekar S. Intestinal intraepithelial lymphocytes are primed for gamma interferon and MIP-1beta expression and display antiviral cytotoxic activity despite severe CD4(+) T-cell depletion in primary simian immunodeficiency virus infection. J Virol 1998; 72:6421-9. [PMID: 9658083 PMCID: PMC109797 DOI: 10.1128/jvi.72.8.6421-6429.1998] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Intraepithelial lymphocytes (IEL) are a critical effector component of the gut-associated lymphoid tissue (GALT) and play an important role in mucosal immunity as well as in the maintenance of the epithelial cell integrity and barrier function. The objective of this study was to determine whether simian immunodeficiency virus (SIV) infection of rhesus macaques would cause alterations in the immunophenotypic profiles of IEL and their mitogen-specific cytokine (gamma interferon [IFN-gamma] and MIP-1beta) responses (by flow cytometry) and virus-specific cytotoxic T-cell (CTL) activity (by the chromium release assay). Virally infected IEL were detected through the entire course of SIV infection by in situ hybridization. Severe depletion of CD4(+) single-positive and CD4(+)CD8(+) double-positive T cells occurred early in primary SIV infection, which was coincident with an increased prevalence of CD8(+) T cells. This was in contrast to a gradual depletion of CD4(+) T cells in peripheral blood. The CD8(+) IEL were the primary producers of IFN-gamma and MIP-1beta and were found to retain their potential to produce both IFN-gamma and MIP-1beta through the entire course of SIV infection. SIV-specific CTL activity was detected in primary IEL at 1, 2, and 4 weeks post-SIV infection. These results demonstrated that IEL may be involved in generating antiviral immune responses early in SIV infection and in suppressing viral infection thereafter. Alterations in homeostasis in epithelia due to severe CD4(+) T-cell depletion accompanied by changes in the cytokine and chemokine production by IEL may play a role in the enteropathogenesis of SIV infection.
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Affiliation(s)
- J J Mattapallil
- Department of Internal Medicine, Division of Infectious Diseases, School of Medicine, University of California, Davis, California, USA
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Smit-McBride Z, Mattapallil JJ, McChesney M, Ferrick D, Dandekar S. Gastrointestinal T lymphocytes retain high potential for cytokine responses but have severe CD4(+) T-cell depletion at all stages of simian immunodeficiency virus infection compared to peripheral lymphocytes. J Virol 1998; 72:6646-56. [PMID: 9658111 PMCID: PMC109855 DOI: 10.1128/jvi.72.8.6646-6656.1998] [Citation(s) in RCA: 175] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/1998] [Accepted: 05/12/1998] [Indexed: 02/08/2023] Open
Abstract
Gastrointestinal complications in human immunodeficiency virus (HIV) infection are indicative of impaired intestinal mucosal immune system. We used simian immunodeficiency virus (SIV)-infected rhesus macaques as an animal model for HIV to determine pathogenic effects of SIV on intestinal T lymphocytes. Intestinal CD4(+) T-cell depletion and the potential for cytokine responses were examined during SIV infection and compared with results for lymphocytes from lymph nodes and blood. Flow cytometric analysis demonstrated severe depletion of CD4(+)CD8(-) single-positive T cells and CD4(+)CD8(+) double-positive T cells in intestinal lamina propria lymphocytes (LPL) and intraepithelial lymphocytes (IEL) during primary SIV infection which persisted through the entire course of SIV infection. In contrast, CD4(+) T-cell depletion was gradual in peripheral lymph nodes and blood. Flow cytometric analysis of intracellular gamma interferon (IFN-gamma) and interleukin-4 (IL-4) production following short-term mitogenic activation revealed that LPL retained same or higher capacity for IFN-gamma production in all stages of SIV infection compared to uninfected controls, whereas peripheral blood mononuclear cells displayed a gradual decline. The CD8(+) T cells were the major producers of IFN-gamma. There was no detectable change in the frequency of IL-4-producing cells in both LPL and peripheral blood mononuclear cells. Thus, severe depletion of CD4(+) LPL and IEL in primary SIV infection accompanied by altered cytokine responses may reflect altered T-cell homeostasis in intestinal mucosa. This could be a mechanism of SIV-associated enteropathy and viral pathogenesis. Dynamic changes in intestinal T lymphocytes were not adequately represented in peripheral lymph nodes or blood.
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Affiliation(s)
- Z Smit-McBride
- Department of Internal Medicine, Division of Infectious Diseases, Microbiology and Immunology, University of California, Davis, California 95616, USA
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Smit-McBride Z, Mattapallil JJ, Villinger F, Ansari AA, Dandekar S. Intracellular cytokine expression in the CD4+ and CD8+ T cells from intestinal mucosa of simian immunodeficiency virus infected macaques. J Med Primatol 1998; 27:129-40. [PMID: 9747954 DOI: 10.1111/j.1600-0684.1998.tb00237.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Isolated intraepithelial lymphocytes (IEL) and lamina propria lymphocytes (LPL) from jejunum of SIV infected animals were examined for alterations in basal cytokine expression by RT-PCR. Remarkable changes in IFNgamma and IL-10 RNA levels were observed in IEL and LPL in SIV infection while IL-4 and IL-2 RNA levels remained unaltered. In addition, the CD4+ and CD8+ LPL were examined for intracellular cytokine production following mitogenic activation by flowcytometry. Both CD4+ and CD8+ T lymphocytes in intestinal mucosa retained the potential to produce IFNgamma in response to mitogenic stimulation in vitro, without a remarkable change in IL-4 production. The dominant IFNgamma cytokine response could be one of the major contributing factors in SIV associated enteropathy.
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Affiliation(s)
- Z Smit-McBride
- Department of Internal Medicine, University of California at Davis 95616, USA
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Smit-McBride Z, Privalsky ML. DNA sequence specificity of the v-erb A oncoprotein/thyroid hormone receptor: role of the P-box and its interaction with more N-terminal determinants of DNA recognition. Mol Endocrinol 1994; 8:819-28. [PMID: 7984144 DOI: 10.1210/mend.8.7.7984144] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The viral erb A oncogene is a mutated allele of a normal cell gene for a thyroid hormone receptor. The DNA recognition properties of the v-erb A protein are altered from those of the thyroid hormone receptor, due in part to a point mutation in the P-box of the zinc-finger domain of the viral allele. We report here the effects of systematically varying this P-box codon; our results suggest that this P-box amino acid contributes to DNA specificity not by promoting recognition of the appropriate response elements, but rather by excluding binding of the erb A protein to inappropriate half-sites. In this manner, DNA recognition by the v-erb A protein appears to differ from that by the glucocorticoid receptor. A variety of P-box amino acids were compatible with recognition of the prototypic AGGTCA half-site; intriguingly, several of these mutant erb A proteins could also recognize a variety of alternative half-site sequences. Recognition of these alternative half-sites required a compatible amino acid sequence in the N terminus of the erb A protein. Our results begin to define a code by which the identity of the amino acids in the zinc-finger and N-terminal domains is reflected in the DNA recognition properties of the receptor.
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Affiliation(s)
- Z Smit-McBride
- Section of Microbiology, University of California at Davis 95616
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Smit-McBride Z. DNA sequence specificity of the v-erb A oncoprotein/thyroid hormone receptor: role of the P-box and its interaction with more N-terminal determinants of DNA recognition. Mol Endocrinol 1994. [DOI: 10.1210/me.8.7.819] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Hall BL, Smit-McBride Z, Privalsky ML. Reconstitution of retinoid X receptor function and combinatorial regulation of other nuclear hormone receptors in the yeast Saccharomyces cerevisiae. Proc Natl Acad Sci U S A 1993; 90:6929-33. [PMID: 8394003 PMCID: PMC47048 DOI: 10.1073/pnas.90.15.6929] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The nuclear hormone receptor family of transcription factors regulates gene expression via a complex combinatorial network of interactions. Of particular interest is the ability of retinoid X receptors (RXRs) to form heterodimers with retinoic acid receptors (RARs) and thyroid hormone receptors (TRs), thereby modifying their activities. We report here that RXR, RAR, and TR function can be reconstituted in the yeast Saccharomyces cerevisiae and demonstrate that the combinatorial regulation seen in vertebrate cells can be reproduced in the yeast background. Using this system, we have shown that RARs respond to a wide variety of retinoid ligands but that RXRs are specific for the 9-cis isomer of retinoic acid. RXR enhanced the activity of RARs and TRs on a variety of hormone response elements without demonstrably altering their DNA specificity. Interestingly, the ability of RXR to potentiate gene activation by RARs and by TRs varied for different receptor isoforms.
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Affiliation(s)
- B L Hall
- Department of Microbiology, University of California, Davis 95616
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Smit-McBride Z, Privalsky ML. Functional domains of the v-erbA protein necessary for oncogenesis are required for transcriptional activation in Saccharomyces cerevisiae. Oncogene 1993; 8:1465-75. [PMID: 8099219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The v-erbA oncogene is a retrovirus-transduced and altered copy of a cellular gene (c-erbA-alpha) for a thyroid hormone receptor. In this paper we show that the v-erbA domains required for transcriptional activation in yeast and for oncogenic function in animal cells are closely congruent. We conclude that the behavior of the v-erbA protein as a transcriptional activator in yeast appears to closely reflect the same biochemical requirements that are necessary for v-erbA function in the neoplastic vertebrate cell. Intriguingly, parallel analyses of c-erbA-alpha and -beta demonstrated unexpected differences in the activities of the two thyroid hormone receptor isoforms in the yeast, perhaps reflecting different functions of these genes in vertebrates. Furthermore, results obtained by analysis of chimeric v-/c-erbA genes suggest that the basal and the hormone-induced transcriptional activity of the nuclear hormone receptors can be modulated independently by distinct structural features within the protein molecule.
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Affiliation(s)
- Z Smit-McBride
- Department of Microbiology, University of California, Davis 95616
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Chen H, Smit-McBride Z, Lewis S, Sharif M, Privalsky ML. Nuclear hormone receptors involved in neoplasia: erb A exhibits a novel DNA sequence specificity determined by amino acids outside of the zinc-finger domain. Mol Cell Biol 1993; 13:2366-76. [PMID: 8096060 PMCID: PMC359557 DOI: 10.1128/mcb.13.4.2366-2376.1993] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The erb A oncogene is a dominant negative allele of a thyroid hormone receptor gene and acts in the cancer cell by encoding a transcriptional repressor. We demonstrate here that the DNA sequence recognition properties of the oncogenic form of the erb A protein are significantly altered from those of the normal thyroid hormone receptors and more closely resemble those of the retinoic acid receptors; this alteration appears to play an important role in defining the targets of erb A action in neoplasia. Unexpectedly, the novel DNA recognition properties of erb A are encoded by an N-terminal region not previously implicated as playing this function in current models of receptor-DNA interaction. Two N-terminal erb A amino acids in particular, histidine 12 and cysteine 32, contribute to this phenomenon, acting in conjunction with amino acids in the zinc finger domain. The effects of the N-terminal domain can be observed at the level of both DNA binding and transcriptional modulation. Our results indicate that unanticipated determinants within the nuclear hormone receptors participate in DNA sequence recognition and may contribute to the differential target gene specificity displayed by different receptor forms.
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Affiliation(s)
- H Chen
- Department of Microbiology, University of California, Davis 95616
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Schnier J, Schwelberger HG, Smit-McBride Z, Kang HA, Hershey JW. Translation initiation factor 5A and its hypusine modification are essential for cell viability in the yeast Saccharomyces cerevisiae. Mol Cell Biol 1991; 11:3105-14. [PMID: 1903841 PMCID: PMC360154 DOI: 10.1128/mcb.11.6.3105-3114.1991] [Citation(s) in RCA: 125] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Translation intitiation factor eIF-5A (previously named eIF-4D) is a highly conserved protein that promotes formation of the first peptide bond. One of its lysine residues is modified by spermidine to form hypusine, a posttranslational modification unique to eIF-5A. To elucidate the function of eIF-5A and determine the role of its hypusine modification, the cDNA encoding human eIF-5A was used as a probe to identify and clone the corresponding genes from the yeast Saccharomyces cerevisiae. Two genes named TIF51A and TIF51B were cloned and sequenced. The two yeast proteins are closely related, sharing 90% sequence identity, and each is ca. 63% identical to the human protein. The purified protein expressed from the TIF51A gene substitutes for HeLa eIF-5A in the mammalian methionyl-puromycin synthesis assay. Strains lacking the A form of eIF-5A, constructed by disruption of TIF51A with LEU2, grow slowly, whereas strains lacking the B form, in which HIS3 was used to disrupt TIF51B, show no growth rate phenotype. However, strains with both TIF51A and TIF51B disrupted are not viable, indicating that eIF-5a is essential for cell growth in yeast cells. Northern (RNA) blot analysis shows two mRNA species, a larger mRNA (0.9 kb) transcribed from TIF51A and a smaller mRNA (0.8 kb) encoded by TIF51B. Under the aerobic growth conditions of this study, the 0.8-kb TIF51B transcript is not detected in the wild-type strain and is expressed only when TIF51A is disrupted. The TIF51A gene was altered by site-directed mutagenesis at the site of hypusination by changing the Lys codon to that for Arg, thereby producing a stable protein that retains the positive charge but is not modified to the hypusine derivative. The plasmid shuffle technique was used to replace the wild-type gene with the mutant form, resulting in failure of the yeast cells to grow. This result indicates that hypusine very likely is required for the vital in vivo function of eIF-5A and suggests a precise, essential role for the polyamine spermidine in cell metabolism.
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Affiliation(s)
- J Schnier
- Department of Biological Chemistry, School of Medicine, University of California, Davis 95616
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Park MH, Wolff EC, Smit-McBride Z, Hershey JW, Folk JE. Comparison of the activities of variant forms of eIF-4D. The requirement for hypusine or deoxyhypusine. J Biol Chem 1991; 266:7988-94. [PMID: 1850732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Eukaryotic protein synthesis initiation factor 4D (eIF-4D) (current nomenclature, eIF-5A) contains the unique amino acid hypusine (N epsilon-(4-amino-2-hydroxybutyl)lysine). The first step in hypusine biosynthesis, i.e. the formation of the intermediate, deoxyhypusine (N epsilon-(4-aminobutyl)lysine), was carried out in vitro using spermidine, deoxyhypusine synthase, and ec-eIF-4D(Lys), an eIF-4D precursor prepared by over-expression of human eIF-4D cDNA in Escherichia coli. In a parallel reaction, using N-(3-aminopropyl)cadaverine in place of spermidine, a variant form of eIF-4D containing homodeoxyhypusine (N epsilon-(5-aminopentyl)lysine) was prepared. Evidence that N-(3-aminopropyl)cadaverine can also act as the amine substrate for deoxyhypusine synthase in intact cells was obtained by incubating putrescine- and spermidine-depleted Chinese hamster ovary cells with [3H]cadaverine. In these cells, in which [3H]cadaverine is readily converted to N-(3-aminopropyl) [3H]cadaverine, small amounts of [3H]homodeoxyhypusine and another 3H-labeled compound, presumed to be N epsilon-(5-amino-2-hydroxy[3H]pentyl)lysine, were found. eIF-4D stimulates methionyl-puromycin synthesis, an in vitro model assay for translation initiation. Whereas the unmodified precursor ec-eIF-4D(Lys) appeared inactive, the deoxyhypusine-containing form provided a significant degree of stimulation. The variant form containing homodeoxyhypusine, on the other hand, showed little or no activity. These findings emphasize the importance of hypusine or deoxyhypusine for the biological activity of eIF-4D and demonstrate the influence of both the length and chemical nature of its amino alkyl side chain.
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Affiliation(s)
- M H Park
- Laboratory of Cellular Development and Oncology, National Institute of Dental Research, National Institutes of Health, Bethesda, Maryland 20892
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Park M, Wolff E, Smit-McBride Z, Hershey J, Folk J. Comparison of the activities of variant forms of eIF-4D. The requirement for hypusine or deoxyhypusine. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)92929-7] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Hershey JW, Smit-McBride Z, Schnier J. The role of mammalian initiation factor eIF-4D and its hypusine modification in translation. Biochim Biophys Acta 1990; 1050:160-2. [PMID: 2119810 DOI: 10.1016/0167-4781(90)90159-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Initiation factor eIF-4D functions late in the initiation pathway, apparently during formation of the first peptide bond. The factor is post-translationally modified at a specific lysine residue by reaction with spermidine and subsequent hydroxylation to form hypusine. A precursor form lacking hypusine is inactive in the assay for methionyl-puromycin synthesis, but activity is restored following in vitro modification to deoxyhypusine, thereby suggesting that the modification is essential for function. Since formylated methionyl-tRNA is less dependent on eIF-4D in the puromycin assay, we postulate that eIF-4D and its hypusine modification may stabilize charged Met-tRNA binding to the peptidyl transferase center of the 60S ribosomal subunit. Analysis of eIF-4D genes in yeast indicate that eIF-4D and its hypusine modification are essential for cell growth.
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Affiliation(s)
- J W Hershey
- Department of Biological Chemistry, School of Medicine, University of California, Davis 95616
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Smit-McBride Z, Schnier J, Kaufman RJ, Hershey JW. Protein synthesis initiation factor eIF-4D. Functional comparison of native and unhypusinated forms of the protein. J Biol Chem 1989; 264:18527-30. [PMID: 2509460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Protein synthesis initiation factor eIF-4D is a relatively abundant protein in mammalian cells and possesses a unique amino acid residue, hypusine. The role of the hypusine modification in eIF-4D function was addressed by studying the function of eIF-4D variants lacking hypusine. The cloned human cDNA encoding eIF-4D was overexpressed in Escherichia coli and a precursor form lacking hypusine was purified. This protein fails to stimulate methionyl-puromycin synthesis in vitro, nor does it significantly inhibit the action of native eIF-4D. Mammalian expression vectors were constructed with the wild-type cDNA and a mutant form in which the codon for lysine-50 (the residue hypusinated) was altered by site-directed mutagenesis to that for arginine. Transient co-transfection of COS-1 cells with the eIF-4D vector and a vector expressing dihydrofolate reductase led to strong synthesis of both eIF-4D and dihydrofolate reductase. This indicates that normal cellular levels of eIF-4D are saturating in these cells and that excess levels of eIF-4D are not detrimental. Cotransfection with the eIF-4D arginine variant caused no effect on dihydrofolate reductase synthesis, in agreement with the in vitro experiments. The inability of the unhypusinated eIF-4D variants to stimulate methionyl-puromycin synthesis in vitro and to affect protein synthesis in vivo strongly suggests that the hypusine modification is required for eIF-4D activity and for its interaction with the 80 S initiation complex in protein synthesis.
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Affiliation(s)
- Z Smit-McBride
- Department of Biological Chemistry, School of Medicine, University of California, Davis 95616
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Smit-McBride Z, Dever TE, Hershey JW, Merrick WC. Sequence determination and cDNA cloning of eukaryotic initiation factor 4D, the hypusine-containing protein. J Biol Chem 1989; 264:1578-83. [PMID: 2492279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Protein synthesis initiation factor 4D (eIF-4D) from mammalian cells contains the post-translationally modified lysine derivative hypusine. A highly purified preparation of the protein from rabbit reticulocytes was subjected to chemical and enzymatic cleavage, and a large number of overlapping peptides were resolved by high performance liquid chromatography and sequenced. Two mixed 14-base DNA probes were synthesized based on suitable amino acid sequences and were used to screen a human cDNA library in lambda gt11. A cDNA insert containing eIF-4D encoding sequences was identified and a 558-base pair EcoRI-PstI fragment was sequenced. Northern blot hybridization of HeLa cell RNA shows a single size class (1.2 kilobase) of mRNA. The DNA encodes a protein comprising 154 residues with a mass of 16,703 daltons. Human eIF-4D matches all of the rabbit peptides sequenced, extending from residue 9 to 154 except for Cys-129 which is Ser in the rabbit protein. The residue modified to hypusine is identified as Lys-50 and the amino terminus is blocked. eIF-4D possesses rather little secondary structure in the amino-terminal two-thirds of the protein, but the carboxyl-terminal third is rich in alpha helices.
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Affiliation(s)
- Z Smit-McBride
- Department of Biological Chemistry, School of Medicine, University of California, Davis 95616
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Smit-McBride Z, Dever TE, Hershey JWB, Merrick WC. Sequence Determination and cDNA Cloning of Eukaryotic Initiation Factor 4D, the Hypusine-containing Protein. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(18)94226-2] [Citation(s) in RCA: 66] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Abstract
We have studied linkage disequilibrium in Drosophila melanogaster in two samples from a wild population and in four large laboratory populations derived from the wild samples. We have assayed four polymorphic enzyme loci, fairly closely linked in the third chromosome: Sod Est-6, Pgm, and Odh. The assay method used allows us to identify the allele associations separately in each of the two homologous chromosomes from each male sampled. We have detected significant linkage disequilibrium between two loci in 16.7% of the cases in the wild samples and in 27.8% of the cases in the experimental populations, considerably more than would be expected by chance alone. We have also found three-locus disequilibria in more instances than would be expected by chance. Some disequilibria present in the wild samples disappear in the experimental populations derived from them, but new ones appear over the generations. The effective population sizes required to generate the observed disequilibria by randomness range from 40 to more than 60,000 individuals in the natural population, depending on which locus pair is considered, and from 100 to more than 60,000 in the experimental populations. These population sizes are unrealistic; the fact that different locus-pairs yield disparate estimates within the same population argues against the likelihood that the disequilibria may have arisen as a consequence of population bottlenecks. Migration, or population mixing, cannot be excluded as the process generating the disequilibria in the wild samples, but can in the experimental populations. We conclude that linkage disequilibrium in these populations is most likely due to natural selection acting on the allozymes, or on loci very tightly linked to them.
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Affiliation(s)
- Z Smit-McBride
- Department of Ecology and Evolutionary Biology, University of California, Irvine 92717
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