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Chen J, Cao D, Fortmann SD, Curcio CA, Feist RM, Crosson JN. Transthyretin proteoforms of intraocular origin in human subretinal fluid. Exp Eye Res 2022; 222:109163. [PMID: 35760119 DOI: 10.1016/j.exer.2022.109163] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 05/24/2022] [Accepted: 06/20/2022] [Indexed: 11/26/2022]
Abstract
Understanding the molecular composition of ocular tissues and fluids could inform new approaches to prevalent causes of blindness. Subretinal fluid accumulating between the photoreceptor outer segments and retinal pigment epithelium (RPE) is potentially a rich source of proteins and lipids normally cycling among outer retinal cells and choroid. Herein, intact post-translationally modified proteins (proteoforms) were extracted from subretinal fluids of five patients with rhegmatogenous retinal detachment (RRD), analyzed by tandem mass spectrometry, and compared to published data on these same proteins as synthesized by other organs. Single-nuclei transcriptomic data from non-diseased human retina/RPE were used to identify whether proteins in subretinal fluid were of potential ocular origin. Two human donor eyes with normal maculas were immunoprobed for transthyretin (TTR) with appropriate controls. The three most abundant proteins detected in subretinal fluid were albumin, TTR, and apolipoprotein A-I. Remarkably, TTR relative to the other proteins was more abundant than its serum counterpart, suggestive of TTR being synthesized predominantly locally. Six post-translationally modified protein forms (proteoforms) of TTR were detected, with the relative amount of glutathionylated TTR being much higher in the subretinal fluid (12-43%) than values reported for serum (<5%) and cerebrospinal fluid (0.4-13%). Moreover, a putative glycosylated TTR dimer of 32,428 Da was detected as the fourth most abundant protein. The high abundance of TTR and putative TTR dimer in subretinal fluid was supported by analysis of available single-nuclei transcriptomic data, which showed strong and specific signal for TTR in RPE. Immunohistochemistry further showed strong diffuse TTR immunoreactivity in choroidal stroma that contrasted with vertically aligned signal in the outer segment zone of the subretinal space and negligible signal in RPE cell bodies. These results suggest that TTR in the retina is synthesized intraocularly, and glutathionylation is crucial for its normal function. Further studies on the composition, function, and quantities of TTR and other proteoforms in subretinal fluid could inform mechanisms, diagnostic methods, and treatment strategies for age-related macular degeneration, familial amyloidosis, and other retinal diseases involving dysregulation of physiologic lipid transfer and oxidative stress.
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Affiliation(s)
- Jianzhong Chen
- Department of Optometry and Vision Science, The University of Alabama at Birmingham, Birmingham, AL, United States.
| | - Dongfeng Cao
- Department of Ophthalmology and Visual Sciences, The University of Alabama at Birmingham, Birmingham, AL, United States
| | - Seth D Fortmann
- Department of Ophthalmology and Visual Sciences, The University of Alabama at Birmingham, Birmingham, AL, United States
| | - Christine A Curcio
- Department of Ophthalmology and Visual Sciences, The University of Alabama at Birmingham, Birmingham, AL, United States.
| | - Richard M Feist
- Department of Ophthalmology and Visual Sciences, The University of Alabama at Birmingham, Birmingham, AL, United States
| | - Jason N Crosson
- Department of Ophthalmology and Visual Sciences, The University of Alabama at Birmingham, Birmingham, AL, United States
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Ribeiro AG, Alves JEF, Soares JCS, dos Santos KL, Jacob ÍTT, da Silva Ferreira CJ, dos Santos JC, de Azevedo RDS, de Almeida SMV, de Lima MDCA. Albumin roles in developing anticancer compounds. Med Chem Res 2021. [DOI: 10.1007/s00044-021-02748-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Abstract
Decompensated liver cirrhosis has a dismal prognosis, with an overall survival of 2-4 years, which is worse than for many oncological diseases. Albumin is an important tool in the management of patients with cirrhosis, since it decreases for less than half the risk for post-paracentesis cardiocirculatory dysfunction and mortality associated with spontaneous bacterial infection, as well as, it triplicates the response to terlipressin in patients with hepatorenal syndrome. Recently, research on albumin has been a hot topic, with important new insights such as the characterization of the pleiotropic effects of albumin (which surpass its oncotic properties) and the concept of effective albumin concentration. In fact, patients with liver cirrhosis present posttranslational modifications on albumin that compromises its function. Those modified albumin forms were proved to have prognostic value and its knowledge may change the paradigm of albumin treatment. In this review, we critically summarize the latest evidence on the potential benefits of albumin in patients with end-stage liver disease.
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Affiliation(s)
- Joana R Carvalho
- Department of Gastroenterology and Hepatology, Hospital Santa Maria, Lisbon, Portugal
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Kim DS, Anantharam P, Hoffmann A, Meade ML, Grobe N, Gearhart JM, Whitley EM, Mahama B, Rumbeiha WK. Broad spectrum proteomics analysis of the inferior colliculus following acute hydrogen sulfide exposure. Toxicol Appl Pharmacol 2018; 355:28-42. [PMID: 29932956 PMCID: PMC6422160 DOI: 10.1016/j.taap.2018.06.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 05/30/2018] [Accepted: 06/01/2018] [Indexed: 12/20/2022]
Abstract
Acute exposure to high concentrations of H2S causes severe brain injury and long-term neurological disorders, but the mechanisms involved are not known. To better understand the cellular and molecular mechanisms involved in acute H2S-induced neurodegeneration we used a broad-spectrum proteomic analysis approach to identify key molecules and molecular pathways involved in the pathogenesis of acute H2S-induced neurotoxicity and neurodegeneration. Mice were subjected to acute inhalation exposure of up to750 ppm of H2S. H2S induced behavioral deficits and severe lesions including hemorrhage in the inferior colliculus (IC). The IC was microdissected for proteomic analysis. Tandem mass tags (TMT) liquid chromatography mass spectrometry (LC-MS/MS)-based quantitative proteomics was applied for protein identification and quantitation. LC-MS/MS identified 598, 562, and 546 altered proteomic changes at 2 h, and on days 2 and 4 post-H2S exposure, respectively. Of these, 77 proteomic changes were statistically significant at any of the 3 time points. Mass spectrometry data were subjected to Perseus 1.5.5.3 statistical analysis, and gene ontology heat map clustering. Expressions of several key molecules were verified to confirm H2S-dependent proteomics changes. Webgestalt pathway overrepresentation enrichment analysis with Panther engine revealed H2S exposure disrupted several biological processes including metabotropic glutamate receptor group 1 and inflammation mediated by chemokine and cytokine signaling pathways among others. Further analysis showed that energy metabolism, integrity of blood-brain barrier, hypoxic, and oxidative stress signaling pathways were also implicated. Collectively, this broad-spectrum proteomics data has provided important clues to follow up in future studies to further elucidate mechanisms of H2S-induced neurotoxicity.
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Affiliation(s)
- Dong-Suk Kim
- Veterinary Diagnostic & Production Animal Medicine, Iowa State University, Ames, IA, USA
| | - Poojya Anantharam
- Veterinary Diagnostic & Production Animal Medicine, Iowa State University, Ames, IA, USA
| | - Andrea Hoffmann
- Henry M Jackson Foundation on contract 711HPW/USAFSAM/FHOF, Wright Patterson Air Force Base, Dayton, OH, USA
| | | | - Nadja Grobe
- 711HPW/RHDJ, Wright Patterson Air Force Base, Dayton, OH, USA
| | - Jeffery M Gearhart
- Henry M Jackson Foundation on contract 711HPW/USAFSAM/FHOF, Wright Patterson Air Force Base, Dayton, OH, USA
| | | | - Belinda Mahama
- Veterinary Diagnostic & Production Animal Medicine, Iowa State University, Ames, IA, USA
| | - Wilson K Rumbeiha
- Veterinary Diagnostic & Production Animal Medicine, Iowa State University, Ames, IA, USA.
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Shamay A, Homans R, Fuerman Y, Levin I, Barash H, Silanikove N, Mabjeesh SJ. Expression of Albumin in Nonhepatic Tissues and its Synthesis by the Bovine Mammary Gland. J Dairy Sci 2005; 88:569-76. [PMID: 15653522 DOI: 10.3168/jds.s0022-0302(05)72719-3] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Albumin is a well-characterized product of the liver. In the present study, objectives were to determine if the albumin gene is also expressed in various nonhepatic tissues in the bovine; whether mammary gland epithelial cells synthesize albumin; and how its synthesis is affected by bovine mastitis. Albumin expression was monitored using reverse transcription-polymerase chain reaction. Tissues examined were: liver, mammary gland, tongue, intestine, lymph gland, testicle, ovary, and uterus. All tissues except the ovary expressed the albumin gene, albeit less so than the liver. The highest level of expression (other than liver) was found in the lymph nodes but expression was also found in the mammary gland. Incubation of mammary gland explants with the labeled amino acid L-[(35)S] methionine resulted in formation of labeled immunoprecipitable albumin, newly synthesized in the explant. Immunoprecipitable albumin in the medium verified that newly synthesized albumin was also secreted into the medium. This shows that the gland itself is a source of milk albumin. Albumin mRNA expression was approximately 4 times higher in mammary gland tissue from 6 mastitic cows compared with expression in mammary tissue from 6 healthy glands. Further, secretion of albumin was increased 3.5-fold from explants of mastitic mammary glands compared with secretion from explants of healthy mammary glands. Addition of lipopolysaccharide increased the synthesis and secretion of albumin in mammary gland cells in a dose-dependent manner. Exposure to lipopolysaccharide accelerated albumin synthesis in a time-dependent manner up to 48 h. These results lead us to suggest that the secretion of albumin by the mammary gland is part of the innate nonspecific defense system.
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Affiliation(s)
- A Shamay
- Institute of Animal Science, Agricultural Research Organization, Volcani Center, Bet Dagan, Israel.
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Gonzalez-Fernandez F. Interphotoreceptor retinoid-binding protein--an old gene for new eyes. Vision Res 2004; 43:3021-36. [PMID: 14611938 DOI: 10.1016/j.visres.2003.09.019] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Evolving 40 times independently, eyes are striking examples of convergent evolution in that 11-cis retinaldehyde is always used for photon capture, yet the mechanism for its regeneration may be dramatically different in between systems. In particular, insects, cephalopods and vertebrates show varying physical separation of the cis-->trans photoisomerization and chromphore reisomerization. In the vertebrate retina, these two processes are actually distributed between different cells. This compartmentalization is made possible by the phylogenetic innovation of the two-layered optic cup of the vertebrate retina. This unprecedented design created the subretinal space as a novel anatomical compartment allowing photoreceptors access to the retinal pigment epithelium (RPE) and Müller cells, the two cell types which share the burden of 11-cis retinoid regeneration. To take advantage of this arrangement, early vertebrates appear to have recruited for retinoid binding, the betabetaalpha-spiral fold proven useful in enoyl-CoA isomerase/hydratases, and the carboxy-terminal proteases for stabilizing hydrophobic ligands. Quadruplication of this functional domain within a single polypeptide lead to the emergence of interphotoreceptor retinoid-binding protein (IRBP). IRBP is the main soluble component of the IPM, and is prevented from diffusing out of the subretinal space because its large size excludes it from the photoreceptor/Müller cell zonulae adheretes. Despite this physical entrapment, IRBP is rapidly turned over within the IPM through a process that coordinates secretion of the protein by the photoreceptors, and its removal from the matrix by RPE and photoreceptor endocytosis. The present review will summarize what is known about the structure and function of IRBP to anticipate future avenues of research.
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Affiliation(s)
- Federico Gonzalez-Fernandez
- Department of Ophthalmology, State University of New York at Buffalo and Medical Research Service, Veteran's Affairs Medical Center, 3495 Bailey Avenue, Buffalo, NY 14215, USA.
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Newsome PN, Hussain MA, Theise ND. Hepatic Oval Cells: Helping Redefine a Paradigm in Stem Cell Biology. Curr Top Dev Biol 2004; 61:1-28. [PMID: 15350395 DOI: 10.1016/s0070-2153(04)61001-5] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- P N Newsome
- Department of Hepatology, University of Edinburgh Edinburgh EH16 4SB, United Kingdom, UK
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Du Z, Patel TB. Albumin: a Galpha(s)-specific guanine nucleotide dissociation inhibitor and GTPase activating protein. Arch Biochem Biophys 2003; 415:221-8. [PMID: 12831845 DOI: 10.1016/s0003-9861(03)00263-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Heterotrimeric GTP binding protein (G protein)-mediated signal transduction events are regulated by their effectors and regulators of G protein signaling (RGS) protein family. The latter proteins function as GTPase activating proteins (GAPs) for G protein alpha subunits and terminate signaling events. In a search for proteins that modulate the activity of the stimulatory G protein of adenylyl cyclase (Galpha(s)), we found that bovine serum albumin (BSA) inhibits the steady-state GTPase activity of Galpha(s), but not the inhibitory G protein (Galpha(i1)). This effect of BSA is mediated by decreasing the rate of GDP dissociation from Galpha(s) and decreasing the rate of GTP binding. Thus, BSA functions as a guanine nucleotide dissociation inhibitor for Galpha(s). Moreover, BSA also increased the intrinsic GTPase activity of Galpha(s), but not Galpha(i1), demonstrating that BSA functions as a Galpha(s)-specific GAP. Using mutants of Galpha(s) (Q227L, Q227N, R201C, and R201K), we demonstrate that BSA mediates its GAP function by modulating the ability of R201 to increase GTPase activity. Moreover, using wild-type and Q227N forms of Galpha(s), our studies demonstrate that the GDI function of BSA decreases the ability of Galpha(s) to stimulate adenylyl cyclase. These findings assign a novel function to BSA as a regulator of G protein signaling.
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Affiliation(s)
- Ziyun Du
- Department of Pharmacology, University of Tennessee, The Health Science Center, 874 Union Avenue, Memphis, TN 38163, USA
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Yano T, Kishimoto T, Tomaru U, Kawarada Y, Kato H, Yoshiki T, Ishikura H. Further evidence of hepatic transdifferentiation in hepatoid adenocarcinomas of the stomach: quantitative analysis of mRNA for albumin and hepatocyte nuclear factor-4α. Pathology 2003. [DOI: 10.1080/0031302021000062389] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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