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- Hoxha, A., et al.
(author)
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Identification of discrete epitopes of Ro52p200 and association with fetal cardiac conduction system manifestations in a rodent model
- 2016
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In: Clinical and Experimental Immunology. - : Wiley-Blackwell. - 0009-9104 .- 1365-2249. ; 186:3, s. 284-291
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Journal article (peer-reviewed)abstract
- Congenital heart block (CHB) is a potentially lethal condition characterized by a third-degree atrioventricular block (AVB). Despite anti-Ro52 antibodies being detected in nearly 90% of mothers of affected children, CHB occurs in only 1-2% of anti-Ro/Sjogrens-syndrome-related antigen A (SSA) autoantibody-positive pregnancies. Maternal antibodies have been suggested to bind molecules crucial to fetal cardiac function; however, it remains unknown whether a single antibody profile associates with CHB or whether several specificities and cross-reactive targets exist. Here, we aimed to define further the reactivity profile of CHB-associated antibodies towards Ro52p200 (amino acid 200-239). We first analysed reactivity of a monoclonal anti-Ro52 antibody shown to induce AVB in rats (7.8C7) and of sera from anti-Ro52p200 antibody-positive mothers of children with CHB towards a panel of modified Ro52p200 peptides, and subsequently evaluated their potential to induce AVB in rats upon transfer during gestation. We observed that CHB maternal sera displayed a homogeneous reactivity profile targeting preferentially the C-terminal part of Ro52p200, in contrast to 7.8C7 that specifically bound the p200 N-terminal end. In particular, amino acid D233 appeared crucial to maternal antibody reactivity towards p200. Despite low to absent reactivity towards rat p200 and different binding profiles towards mutated rat peptides indicating recognition of different epitopes within Ro52p200, immunoglobulin (Ig)G purified from two mothers of children with CHB could induce AVB in rats. Our findings support the hypothesis that several fine antibody specificities and cross-targets may exist and contribute to CHB development in anti-Ro52 antibody-positive pregnancies.
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- Kvarnstrom, M, et al.
(author)
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Autoantibodies to the functionally active RING-domain of Ro52/SSA are associated with disease activity in patients with lupus
- 2013
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In: Lupus. - : SAGE Publications. - 1477-0962 .- 0961-2033. ; 22:5, s. 477-485
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Journal article (peer-reviewed)abstract
- The Ro52 protein of the Ro/SSA antigen was recently defined as an E3 ligase controlling cytokine production. Autoantibodies from systemic lupus erythematosus (SLE) patients targeting the Ro52-RING domain, containing the E3 ligase activity, have been shown to inhibit the E3 ligase activity of Ro52. The objective of the present study was to investigate correlations between clinical parameters in patients with SLE and levels of Ro/SSA (Ro52 and Ro60) and La/SSB autoantibodies, including autoantibodies directed towards the functional RING and B-box domains of the Ro52 protein. SLE patients ( n = 232) were clinically examined and disease activity indices collected concurrently to blood sampling. The samples were analyzed for immunological parameters including autoantibodies. Ro52 autoantibody levels were associated with more variables than the other analyzed antibodies and were significantly associated with several individual items related to sSS and the diagnosis of sSS itself ( p = 0.004). Other associated variables were high sedimentation rate ( p = 0.0003), levels of immunoglobulins ( p = 0.0003), and an inverse correlation with levels of lymphocytes ( p = 0.003) and leukocytes ( p = 0.01). Antibodies to the RING domain of Ro52, which is the functionally active domain with E3 ligase activity, were significantly correlated with disease activity as measured by the SLAM score. We conclude that autoantibodies against Ro52 and in particular its functional RING domain are important in lupus patients and associated with several clinical and laboratory features of the disease. The impact on disease activity of Ro52-RING specific antibodies was especially noted, and could imply a functional role for these autoantibodies in inhibiting Ro52 activity, which is important for the control of proinflammatory cytokine production, including type 1 interferons.
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- Mohamed, Rana K., et al.
(author)
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The Missing C-1-C-5 Cycloaromatization Reaction : Triplet State Antiaromaticity Relief and Self-Terminating Photorelease of Formaldehyde for Synthesis of Fulvenes from Enynes
- 2015
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In: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 137:49, s. 15441-15450
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Journal article (peer-reviewed)abstract
- The last missing example of the four archetypical cycloaromatizations of enediynes and enynes was discovered by combining a twisted alkene excited state with a new self-terminating path for intramolecular conversion of diradicals into closed-shell products. Photoexcitation of aromatic enynes to a twisted alkene triplet state creates a unique stereoelectronic situation, which is facilitated by the relief of excited state antiaromaticity of the benzene ring. This enables the usually unfavorable 5-endo-trig cyclization and merges it with 5-exo-dig closure. The 1,4-diradical product of the C1-C5 cyclization undergoes internal H atom transfer that is coupled with the fragmentation of an exocyclic C-C bond. This sequence provides efficient access to benzofulvenes from enynes and expands the utility of self-terminating aromatizing enyne cascades to photochemical reactions. The key feature of this self-terminating reaction is that, despite the involvement of radical species in the key cyclization step, no external radical sources or quenchers are needed to provide the products. In these cascades, both radical centers are formed transiently and converted to the closed-shell products via intramolecular H-transfer and C-C bond fragmentation. Furthermore, incorporating C-C bond cleavage into the photochemical self-terminating cyclizations of enynes opens a new way for the use of alkenes as alkyne equivalents in organic synthesis.
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- Asplund, Olof, et al.
(author)
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Islet Gene View-a tool to facilitate islet research
- 2022
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In: Life Science Alliance. - : Life Science Alliance, LLC. - 2575-1077. ; 5:12
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Journal article (peer-reviewed)abstract
- Characterization of gene expression in pancreatic islets and its alteration in type 2 diabetes (T2D) are vital in understanding islet function and T2D pathogenesis. We leveraged RNA sequencing and genome-wide genotyping in islets from 188 donors to create the Islet Gene View (IGW) platform to make this information easily accessible to the scientific community. Expression data were related to islet phenotypes, diabetes status, other islet-expressed genes, islet hormone-encoding genes and for expression in insulin target tissues. The IGW web application produces output graphs for a particular gene of interest. In IGW, 284 differentially expressed genes (DEGs) were identified in T2D donor islets compared with controls. Forty percent of DEGs showed cell-type enrichment and a large proportion significantly co-expressed with islet hormone-encoding genes; glucagon (GCG, 56%), amylin (IAPP, 52%), insulin (INS, 44%), and somatostatin (SST, 24%). Inhibition of two DEGs, UNC5D and SERPINE2, impaired glucose-stimulated insulin secretion and impacted cell survival in a human beta-cell model. The exploratory use of IGW could help designing more comprehensive functional follow-up studies and serve to identify therapeutic targets in T2D.
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- Aziz, Emad F., et al.
(author)
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Interaction between liquid water and hydroxide revealed by core-hole de-excitation
- 2008
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In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 455:7209, s. 89-91
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Journal article (peer-reviewed)abstract
- The hydroxide ion plays an important role in many chemical and biochemical processes in aqueous solution(1). But ourmolecular- level understanding of its unusual and fast transport in water, and of the solvation patterns that allow fast transport, is far from complete. One proposal seeks to explain the properties and behaviour of the hydroxide ion by essentially regarding it as a water molecule that is missing a proton(2), and by inferring transport mechanisms and hydration structures from those of the excess proton. A competing proposal invokes instead unique and interchanging hydroxide hydration complexes, particularly the hypercoordinated OH-(H2O)(4) species and tri- coordinated OH-(H2O)(3) that can form a transient hydrogen bond between the H atom of the OH- and a neighbouring water molecule(3-5). Here we report measurements of core- level photoelectron emission and intermolecular Coulombic decay(6-8) for an aqueous hydroxide solution, which show that the hydrated hydroxide ion is capable of transiently donating a hydrogen bond to surrounding watermolecules. In agreement with recent experimental studies of hydroxide solutions(9-12), our finding thus supports the notion that the hydration structure of the hydroxide ion cannot be inferred from that of the hydrated excess proton.
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