| 1. |
- van de Ven, Johannes P. H., et al.
(författare)
-
A functional variant in the CFI gene confers a high risk of age-related macular degeneration
- 2013
-
Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 45:7, s. 813-813
-
Tidskriftsartikel (refereegranskat)abstract
- Up to half of the heritability of age-related macular degeneration (AMD) is explained by common variants(1-5). Here, we report the identification of a rare, highly penetrant missense mutation in CFI encoding a p.Gly119Arg substitution that confers high risk of AMD (P = 3.79 x 10(-6); odds ratio (OR) = 22.20, 95% confidence interval (CI) = 2.98-164.49). Plasma and sera from cases carrying the p.Gly119Arg substitution mediated the degradation of C3b, both in the fluid phase and on the cell surface, to a lesser extent than those from controls. Recombinant protein studies showed that the Gly119Arg mutant protein is both expressed and secreted at lower levels than wild-type protein. Consistent with these findings, human CFI mRNA encoding Arg119 had reduced activity compared to wild-type mRNA encoding Gly119 in regulating vessel thickness and branching in the zebrafish retina. Taken together, these findings demonstrate that rare, highly penetrant mutations contribute to the genetic burden of AMD.
|
|
| 2. |
- Da Costa, Mariana Gaya, et al.
(författare)
-
Age and sex-associated changes of complement activity and complement levels in a healthy caucasian population
- 2018
-
Ingår i: Frontiers in Immunology. - : Frontiers Media SA. - 1664-3224. ; 9:NOV
-
Tidskriftsartikel (refereegranskat)abstract
- Introduction: The complement system is essential for an adequate immune response. Much attention has been given to the role of complement in disease. However, to better understand complement in pathology, it is crucial to first analyze this system under different physiological conditions. The aim of the present study was therefore to investigate the inter-individual variation in complement activity and the influences of age and sex. Methods: Complement levels and functional activity were determined in 120 healthy volunteers, 60 women, 60 men, age range 20-69 year. Serum functional activity of the classical pathway (CP), lectin pathway activated by mannan (MBL-LP) and alternative pathway (AP) was measured in sera, using deposition of C5b-9 as readout. In addition, levels of C1q, MBL, MASP-1, MASP-2, ficolin-2, ficolin-3, C2, C4, C3, C5, C6, C7, C8, C9, factor B, factor D, properdin, C1-inhibitor and C4b-binding protein, were determined. Age- and sex-related differences were evaluated. Results: Significantly lower AP activity was found in females compared to males. Further analysis of the AP revealed lower C3 and properdin levels in females, while factor D concentrations were higher. MBL-LP activity was not influenced by sex, but MBL and ficolin-3 levels were significantly lower in females compared to males. There were no significant differences in CP activity or CP components between females and males, nevertheless females had significantly lower levels of the terminal components. The CP and AP activity was significantly higher in the elderly, in contrast to MBL-LP activity. Moreover, C1-inhibitor, C5, C8, and C9 increased with age in contrast to a decrease of factor D and C3 levels. In-depth analysis of the functional activity assays revealed that MBL-LP activity was predominantly dependent on MBL and MASP-2 concentration, whereas CP activity relied on C2, C1-inhibitor and C5 levels. AP activity was strongly and directly associated with levels of C3, factor B and C5. Conclusion: This study demonstrated significant sex and age-related differences in complement levels and functionality in the healthy population. Therefore, age and sex analysis should be taken into consideration when discussing complement-related pathologies and subsequent complement-targeted therapies.
|
|
| 3. |
- Groeneveld, Tom, et al.
(författare)
-
Interactions of the extracellular matrix proteoglycans decorin and biglycan with C1q and collectins
- 2005
-
Ingår i: Journal of Immunology. - 1550-6606. ; 175:7, s. 4715-4723
-
Tidskriftsartikel (refereegranskat)abstract
- Decorin and biglycan are closely related abundant extracellular matrix proteoglycans that have been shown to bind to C1q. Given the overall structural similarities between C1q and mannose-binding lectin (MBL), the two key recognition molecules of the classical and the lectin complement pathways, respectively, we have examined functional consequences of the interaction of C1q and MBL with decorin and biglycan. Recombinant forms of human decorin and biglycan bound C1q via both collagen and globular domains and inhibited the classical pathway. Decorin also bound C1 without activating complement. Furthermore, decorin and biglycan bound efficiently to MBL, but only biglycan could inhibit activation of the lectin pathway. Other members of the collectin family, including human surfactant protein D, bovine collectin-43, and conglutinin also showed binding to decorin and biglycan. Decorin and biglycan strongly inhibited C1q binding to human endothelial cells and U937 cells, and biglycan suppressed C1q-induced MCP-1 and IL-8 production by human endothelial cells. In conclusion, decorin and biglycan act as inhibitors of activation of the complement cascade, cellular interactions, and proinflammatory cytokine production mediated by C1q. These two proteoglycans are likely to down-regulate proinflammatory effects mediated by C1q, and possibly also the collectins, at the tissue level.
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Mastellos, Dimitrios C., et al.
(författare)
-
Taming hemodialysis-induced inflammation : Are complement C3 inhibitors a viable option?
- 2019
-
Ingår i: Clinical Immunology. - : Elsevier BV. - 1521-6616. ; 198, s. 102-105
-
Tidskriftsartikel (refereegranskat)abstract
- Owing to an increasing shortage of donor organs, the majority of patients with end-stage kidney disease remains reliant on extracorporeal hemodialysis (HD) in order to counter the lifelong complications of a failing kidney. While HD remains a life-saving option for these patients, mounting evidence suggests that it also fuels a vicious cycle of thromboinflammation that can increase the risk of cardiovascular disease. During HD, blood-borne innate immune systems become inappropriately activated on the biomaterial surface, instigating proinflammatory reactions that can alter endothelial and vascular homeostasis. Complement activation, early during the HD process, has been shown to fuel a multitude of detrimental thromboinflammatory reactions that collectively contribute to patient morbidity. Here we discuss emerging aspects of complement's involvement in HD-induced inflammation and put forth the concept that targeted intervention at the level of C3 might constitute a promising therapeutic approach in HD patients.
|
|
| 7. |
- Proletov, Ian, et al.
(författare)
-
Primary and secondary glomerulonephritides 1.
- 2014
-
Ingår i: Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association. - : Oxford University Press (OUP). - 1460-2385. ; 29 Suppl 3:May, s. 186-200
-
Tidskriftsartikel (refereegranskat)
|
|
| 8. |
- Smailhodzic, Dzenita, et al.
(författare)
-
Zinc supplementation inhibits complement activation in age-related macular degeneration.
- 2014
-
Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 9:11
-
Tidskriftsartikel (refereegranskat)abstract
- Age-related macular degeneration (AMD) is the leading cause of blindness in the Western world. AMD is a multifactorial disorder but complement-mediated inflammation at the level of the retina plays a pivotal role. Oral zinc supplementation can reduce the progression of AMD but the precise mechanism of this protective effect is as yet unclear. We investigated whether zinc supplementation directly affects the degree of complement activation in AMD and whether there is a relation between serum complement catabolism during zinc administration and the complement factor H (CFH) gene or the Age-Related Maculopathy susceptibility 2 (ARMS2) genotype. In this open-label clinical study, 72 randomly selected AMD patients in various stages of AMD received a daily supplement of 50 mg zinc sulphate and 1 mg cupric sulphate for three months. Serum complement catabolism-defined as the C3d/C3 ratio-was measured at baseline, throughout the three months of supplementation and after discontinuation of zinc administration. Additionally, downstream inhibition of complement catabolism was evaluated by measurement of anaphylatoxin C5a. Furthermore, we investigated the effect of zinc on complement activation in vitro. AMD patients with high levels of complement catabolism at baseline exhibited a steeper decline in serum complement activation (p<0.001) during the three month zinc supplementation period compared to patients with low complement levels. There was no significant association of change in complement catabolism and CFH and ARMS2 genotype. In vitro zinc sulphate directly inhibits complement catabolism in hemolytic assays and membrane attack complex (MAC) deposition on RPE cells. This study provides evidence that daily administration of 50 mg zinc sulphate can inhibit complement catabolism in AMD patients with increased complement activation. This could explain part of the mechanism by which zinc slows AMD progression.
|
|
| 9. |
|
|
| 10. |
|
|
