Thioredoxin reduces complement factor H and alters its complement regulatory function
Ontology highlight
ABSTRACT:
INSTRUMENT(S): LTQ Orbitrap
ORGANISM(S): Homo Sapiens (human)
TISSUE(S): Blood Plasma
SUBMITTER: 
Jason Wong
LAB HEAD: Steven Krilis
PROVIDER: PXD009558 | Pride | 2019-05-20
REPOSITORIES: Pride
Publications
Dual roles of different redox forms of complement factor H in protecting against age related macular degeneration.
Krilis Matthew M Qi Miao M Qi Jian J Wong Jason W H JWH Guymer Robyn R Liew Gerald G Hunyor Alex P AP Madigan Michele M McCluskey Peter P Weaver James J Krilis Steven A SA Giannakopoulos Bill B
Free radical biology & medicine 20180922
Complement Factor H (CFH) is an important inhibitor of the alternate complement pathway in Bruch's membrane (BM), located between the choriocapillaris and the retinal pigment epithelium. Furthermore dysfunction of its activity as occurs with certain polymorphisms is associated with an increased risk of age related macular degeneration (AMD). The retina is a site of high generation of reactive oxygen species (ROS) and dysfunction of redox homeostasis in this milieu also contributes to AMD pathoge ...[more]
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Project description:Nitrosative stress has been implicated in the pathogenesis of age related macular degeneration (AMD). Tyrosine nitration is a unique type of post translational modification that occurs in the setting of inflammation and nitrosative stress. To date, the significance and functional implications of tyrosine nitration of complement factor H (CFH), a key complement regulator in the eye has not been explored, and is examined in this study in the context of AMD pathogenesis. Sections of eyes from deceased individuals with AMD (n = 5) demonstrated the presence of immunoreactive nitrotyrosine CFH. We purified nitrated CFH from retinae from 2 AMD patients. Mass spectrometry of CFH isolated from AMD eyes revealed residues in domains critical for binding to heparan sulphate glycosaminoglycans (GAGs), lipid peroxidation by-products and complement (C) 3b were nitrated. Functional studies revealed that nitrated CFH did not bind to lipid peroxidation products, nor to the GAG of perlecan nor to C3b. There was loss of cofactor activity for Factor I mediated cleavage of C3b with nitrated CFH compared to non-nitrated CFH. CFH inhibits, but nitrated CFH significantly potentiates, the secretion of the pro-inflammatory and angiogenic cytokine IL-8 from monocytes that have been stimulated with lipid peroxidation by-products. AMD patients (n = 30) and controls (n = 30) were used to measure plasma nitrated CFH using a novel ELISA. AMD patients had significantly elevated nitrated CFH levels compared to controls (p = 0.0117). These findings strongly suggest that nitrated CFH contributes to AMD progression, and is a target for therapeutic intervention.
2017-08-29 | PXD005613 | Pride
Project description:Purpose: The complement system is closely linked to the pathogenesis of age-related macular degeneration (AMD). Several complement genes are expressed in retinal pigment epithelium (RPE), and complement proteins accumulate in drusen. Further, a common variant of complement factor H (CFH) confers increased risk of developing AMD. Because the mechanisms by which changes in the function of CFH influence development of AMD are unclear, we examined ocular complement expression as a consequence of age in control and CFH null mutant mice. Methods: Gene expression in neuroretinas and RPE/choroid from young and aged WT and Cfh-/- C57BL/6J mice was analysed by microarrays. Expression of a wide range of complement genes was compared to expression in splenocytes and in liver tissue by qRT-PCR. Results: An age-associated increased expression of complement, particularly C1q, C3 and Factor B, in the RPE/choroid coincided with increased expression of the negative regulators Cfh and Cd59a in the neuroretina. Young mice deficient in CFH expressed Cd59a similar to WT, but failed to upregulate Cd59a expression with age. Both hepatic and splenic expression of Cd59a increased with age regardless of Cfh genotype. Conclusions: While the connection between CFH deficiency and failure to up-regulate CD59a remains unknown, these results suggest that expression of CD59 is tissue-specific and that neuroretinal regulation depends on CFH. This could contribute to the visual functional deficits and morphological changes in the Cfh-/- mouse retina that occur with age, and further suggests that deficient neuroretinal regulation of complement could represent an early event in AMD.
2012-10-02 | GSE38671 | GEO
Project description:Purpose: The complement system is closely linked to the pathogenesis of age-related macular degeneration (AMD). Several complement genes are expressed in retinal pigment epithelium (RPE), and complement proteins accumulate in drusen. Further, a common variant of complement factor H (CFH) confers increased risk of developing AMD. Because the mechanisms by which changes in the function of CFH influence development of AMD are unclear, we examined ocular complement expression as a consequence of age in control and CFH null mutant mice. Methods: Gene expression in neuroretinas and RPE/choroid from young and aged WT and Cfh-/- C57BL/6J mice was analysed by microarrays. Expression of a wide range of complement genes was compared to expression in splenocytes and in liver tissue by qRT-PCR. Results: An age-associated increased expression of complement, particularly C1q, C3 and Factor B, in the RPE/choroid coincided with increased expression of the negative regulators Cfh and Cd59a in the neuroretina. Young mice deficient in CFH expressed Cd59a similar to WT, but failed to upregulate Cd59a expression with age. Both hepatic and splenic expression of Cd59a increased with age regardless of Cfh genotype. Conclusions: While the connection between CFH deficiency and failure to up-regulate CD59a remains unknown, these results suggest that expression of CD59 is tissue-specific and that neuroretinal regulation depends on CFH. This could contribute to the visual functional deficits and morphological changes in the Cfh-/- mouse retina that occur with age, and further suggests that deficient neuroretinal regulation of complement could represent an early event in AMD. Gene expression in neuroretinas and RPE/choroid from young and aged WT and Cfh-/- mice, 4 biological replicates in each group.
2012-10-02 | E-GEOD-38671 | biostudies-arrayexpress
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2020-10-19 | PXD015431 | Pride
Project description:Thiol-based redox post-translational modifications have emerged as important mechanisms of signaling and regulation in all organisms. In this context, the small ubiquitous oxido-reductase thioredoxin (Trx) plays a key role by controlling the thiol-disulfide status of target proteins. Recent redox proteomic studies revealed hundreds of proteins regulated by glutathionylation and nitrosylation in the unicellular green alga Chlamydomonas reinhardtii while much less is known about the thioredoxin interactome, called thioredoxome hereafter, in this photosynthetic model organism. Using a quantitative large scale proteomic analysis based on the in vitro reconstitution of the enzymatic thioredoxin system (NADPH, NTR, Trx) within an acellular extract and followed by an isotopic labeling with cleavable Isotopic-Coded Affinity Tag reagents, we identified 1052 Trx-targeted cysteines spread over 602 proteins. These Trx-targets participate in a wide variety of metabolic pathways and cellular processes. This approach, combined with the affinity purification approach study (PXD006097) broadens not only the redox regulation to new enzymes involved in metabolic pathways already known to be regulated by thioredoxins (carbon, lipid and energy metabolism) but also shed light on cellular processes for which data supporting a putative redox regulation in these processes are scarce (aromatic amino-acid biosynthesis, nuclear transport,…). Moreover, by comparing this thioredoxome with proteomic data for glutathionylation and nitrosylation at the protein and cysteine levels, this work confirms the existence of a complex redox regulation network in Chlamydomonas and provides evidence of a tremendous selectivity of redox post-translational modifications for specific cysteines residues.
2017-07-28 | PXD006116 | Pride
Project description:Thioredoxin (Trx) is a ubiquitous oxidoreductase maintaining protein-bound cysteine residues in the reduced thiol state. Here, we combined a well-established method to trap Trx substrates with the power of bacterial genetics to comprehensively characterize the in vivo Trx redox interactome in the model bacterium Escherichia coli. Using strains engineered to optimize trapping, we report the identification of a total 257 Trx substrates, including 191 that had never been reported to depend on Trx for reduction. The newly identified Trx substrates are involved in a variety of cellular processes, ranging from energy metabolism to amino acid synthesis and transcription. The interaction between Trx and two of its newly identified substrates, a protein required for the import of most carbohydrates, PtsI, and the bacterial actin homolog MreB was studied in detail. We provide direct evidence that PtsI and MreB contain cysteine residues that are susceptible to oxidation and that participate in the formation of an intermolecular disulfide with Trx. By considerably expanding the number of Trx targets, our work highlights the role played by this major oxidoreductase in a variety of cellular processes. Moreover, as the dependence on Trx for reduction is often conserved across species, it also provides insightful information on the interactome of Trx in organisms other than E. coli
2016-04-19 | PXD003098 | Pride
Project description:Although elevated KCNH2-3.1 potassium channel expression is associated with cognitive dysfunctions and with schizophrenia, little is known about the pathophysiology of synapses in patient neurons and how elevated levels of KCNH2-3.1 potassium channel could lead to synaptic deficits in humans. Here, we identified specific and delayed disruption of hippocampal-mPFC synaptic transmission and connection unexpectedly associated with age-dependent reduction of SERPING1, CFH and CD74 in the KCNH2-3.1 overexpression transgenic mice, and dysfunctional interactions between hippocampus and prefrontal cortex in the fMRI coupling signal during working memory encoding in healthy subjects carrying schizophrenia-associated risk alleles of KCNH2 potassium channel. These three genes are enriched in neurons or microglia, and reduced expression of these genes dysregulates the complement cascade activation underlying impaired synaptic connectivity of hippocampal-mPFC projections. Knockdown of these genes’ expression impairs synapse formation, and replenishing reduced CFH gene expression rescues KCNH2-3.1-induced impaired synaptogenesis. Our results uncover a previously unrecognized role of truncated KCNH2-3.1 potassium channel mediating reduced expression of three genes mentioned above, which enhances aberrant complement cascade activation during development. These results direct an important conceptual advance that truncated KCNH2-3.1 causes synapse loss mediated by abnormally activated complement system, rather than aberrant neuronal firing, may represent the therapeutic targets for a number of patients with schizophrenia.
2019-08-23 | GSE118989 | GEO
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2016-10-10 | PXD003354 | Pride
Project description:The Caenorhabditis elegans oxidative stress response transcription factor, SKN-1, is essential for the maintenance of redox homeostasis and is a functional ortholog of the Nrf family of transcription factors. The numerous levels of regulation that govern these transcription factors underscore their importance. Here, we add a thioredoxin, encoded by trx-1, to the expansive list of SKN-1 regulators. We report that loss of trx-1 promotes nuclear localization of intestinal SKN-1 in a redox-independent, cell non-autonomous fashion from the ASJ neurons. Furthermore, this regulation is not general to the thioredoxin family, as two other C. elegans thioredoxins TRX-2 and TRX-3 do not play a role in this process. Moreover, TRX-1-dependent regulation requires signaling from the p38 MAPK signaling pathway. However, while TRX-1 regulates SKN-1 nuclear localization, SKN-1 transcriptional activity remains largely unaffected. Interestingly, RNA-Seq revealed that loss of trx-1 elicits a general, organism-wide down-regulation of several classes of genes; those encoding for collagens and lipid transport and localization being most prevalent. However, one prominent lipase-related gene, lips-6, is highly up regulated upon loss of trx-1 in a skn-1-dependent manner. Together, these results uncover a novel role for a thioredoxin in regulating intestinal SKN-1 nuclear localization in a cell non-autonomous manner, thereby contributing to the understanding of the processes involved in maintaining redox homeostasis throughout an organism. Four samples were analyzed: Two nematode strains were analyzed, each under non-stressed and stressed (10mM NaAs) conditions
2016-04-01 | E-GEOD-77976 | biostudies-arrayexpress
Project description:The Caenorhabditis elegans oxidative stress response transcription factor, SKN-1, is essential for the maintenance of redox homeostasis and is a functional ortholog of the Nrf family of transcription factors. The numerous levels of regulation that govern these transcription factors underscore their importance. Here, we add a thioredoxin, encoded by trx-1, to the expansive list of SKN-1 regulators. We report that loss of trx-1 promotes nuclear localization of intestinal SKN-1 in a redox-independent, cell non-autonomous fashion from the ASJ neurons. Furthermore, this regulation is not general to the thioredoxin family, as two other C. elegans thioredoxins TRX-2 and TRX-3 do not play a role in this process. Moreover, TRX-1-dependent regulation requires signaling from the p38 MAPK signaling pathway. However, while TRX-1 regulates SKN-1 nuclear localization, SKN-1 transcriptional activity remains largely unaffected. Interestingly, RNA-Seq revealed that loss of trx-1 elicits a general, organism-wide down-regulation of several classes of genes; those encoding for collagens and lipid transport and localization being most prevalent. However, one prominent lipase-related gene, lips-6, is highly up regulated upon loss of trx-1 in a skn-1-dependent manner. Together, these results uncover a novel role for a thioredoxin in regulating intestinal SKN-1 nuclear localization in a cell non-autonomous manner, thereby contributing to the understanding of the processes involved in maintaining redox homeostasis throughout an organism.
2016-04-01 | GSE77976 | GEO