Molecular composition of drusen and possible involvement of anti-retinal autoimmunity in two different forms of macular degeneration in cynomolgus monkey (Macaca fascicularis)

Department of Ophthalmology, Juntendo University, Edo, Tōkyō, Japan
The FASEB Journal (Impact Factor: 5.48). 10/2005; 19(12):1683-5. DOI: 10.1096/fj.04-3525fje
Source: PubMed

ABSTRACT We have previously reported a cynomolgus monkey (Macaca fascicularis) pedigree with early onset macular degeneration that develops drusen at 2 yr after birth. In this study, the molecular composition of drusen in monkeys affected with late onset and early onset macular degeneration was both characterized. Involvement of anti-retinalautoimmunity in the deposition of drusen and the pathogenesis of the disease was also evaluated. Funduscopic and histological examinations were performed on 278 adult monkeys (mean age=16.94 yr) for late onset macular degeneration. The molecular composition of drusen was analyzed by immunohistochemistry and/or direct proteome analysis using liquid chromatography tandem mass spectroscopy (LC-MS/MS). Anti-retinal autoantibodies in sera were screened in 20 affected and 10 age-matched control monkeys by Western blot techniques. Immunogenic molecules were identified by 2D electrophoresis and LC-MS/MS. Relative antibody titer against each antigen was determined by ELISA in sera from 42 affected (late onset) and 41 normal monkeys. Yellowish-white spots in the macular region were observed in 90 (32%) of the late onset monkeys that were examined. Histological examination demonstrated that drusen or degenerative retinal pigment epithelium (RPE) cells were associated with the pigmentary abnormalities. Drusen in both late and early onset monkeys showed immunoreactivities for apolipoprotein E, amyloid P component, complement component C5, the terminal C5b-9 complement complex, vitronectin, and membrane cofactor protein. LC-MS/MS analyses identified 60 proteins as constituents of drusen, including a number of common components in drusen of human age-related macular degeneration (AMD), such as annexins, crystallins, immunoglobulins, and complement components. Half of the affected monkeys had single or multiple autoantibodies against 38, 40, 50, and 60 kDa retinal proteins. The reacting antigens of 38 and 40 kDa were identified as annexin II and mu-crystallin, respectively. Relative antibody titer against annexin II in affected monkeys was significantly higher than control animals (P<0.01). Significant difference was not observed in antibody titer against mu-crystallin; however, several affected monkeys showed considerably elevated titer (360-610%) compared with the mean for unaffected animals. Monkey drusen both in late and early onset forms of macular degeneration had common components with drusen in human AMD patients, indicating that chronic inflammation mediated by complement activation might also be involved in the formation of drusen in these affected monkeys. The high prevalence of anti-retinalautoantibodies in sera from affected monkeys demonstrated an autoimmune aspect of the pathogenesis of the disease. Although further analyses are required to determine whether and how autoantibodies against annexin II or mu-crystallin relate to the pathogenesis of the disease, it could be hypothesized that immune responses directed against these antigens might trigger chronic activation of the complement cascade at the site of drusen formation.

Download full-text


Available from: Yasuhiro Yoshikawa, Aug 11, 2015
  • Source
    • "itronectin , complement receptor 1 , CFH , and major histocompatibility complex II antigen ( Hageman et al . , 2001 ; Johnson et al . , 2006 ) . Moreover , significantly el - evated anti - retinal antibodies have been found in human AMD patient serum and in the drusen of a cynomolgus monkey model of AMD ( Gu et al . , 2003 ; Patel et al . , 2005 ; Umeda et al . , 2005 ) . Progress in understanding the pathogenesis of AMD has been hampered by the lack of a suitable animal model . Mice deficient in Ccl2 or its receptor develop retinal degeneration with many pathological similarities to AMD . However , this an - imal model develops the AMD - like phenotype only in its sen - escent stage ( Ambati et al ."
  • Source
    • "Recent studies indicate that innate immunity and inflammation are related to AMD pathogenesis [24] [25]. The evidence for the involvement of innate immunity and inflammation in AMD pathogenesis includes accumulation of immunoglobulin and complement components in drusen [26] [27] [28], the association between genetic variants of complement factor H, factor B, C2, C3, factor I and risk for AMD [29] [30] [31] [32] [33] [34] [35] [36] [37], and elevated serum CRP levels in AMD patients [38] [39] [40]. Emerging evidence indicates dietary lutein and zeaxanthin have anti-inflammation functions, including a reduction of serum levels of CRP and sICAM [41] [42] [43] [44]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Oxidative damage and inflammation are related to the pathogenesis of age-related macular degeneration (AMD). Epidemiologic studies suggest that insufficient dietary lutein and zeaxanthin intake or lower serum zeaxanthin levels are associated with increased risk for AMD. The objective of this work is to test the protective effects of lutein and zeaxanthin against photooxidative damage to retinal pigment epithelial cells (RPE) and oxidation-induced changes in expression of inflammation-related genes. To mimic lipofuscin-mediated photooxidation in vivo, we used ARPE-19 cells that accumulated A2E, a lipofuscin fluorophore and photosensitizer, as a model system to investigate the effects of lutein and zeaxanthin supplementation. The data show that supplementation with lutein or zeaxanthin in the medium resulted in accumulation of lutein or zeaxanthin in the RPE cells. The concentrations of lutein and zeaxanthin in the cells were 2- to 14-fold of that detected in the medium, indicating that ARPE-19 cells actively take up lutein or zeaxanthin. As compared with untreated cells, exposure of A2E-containing RPE to blue light resulted in a 40-60% decrease in proteasome activity, a 50-80% decrease in expression of CFH and MCP-1, and an∼20-fold increase in expression of IL-8. The photooxidation-induced changes in expression of MCP-1, IL-8, and CFH were similar to those caused by chemical inhibition of the proteasome, suggesting that inactivation of the proteasome is involved in the photooxidation-induced alteration in expression of these inflammation-related genes. Incubation of the A2E-containing RPE with lutein or zeaxanthin prior to blue light exposure significantly attenuated the photooxidation-induced inactivation of the proteasome and photooxidation-induced changes in expression of MCP-1, IL-8, and CFH. Together, these data indicate that lutein or zeaxanthin modulates inflammatory responses in cultured RPE in response to photooxidation. Protecting the proteasome from oxidative inactivation appears to be one of the mechanisms by which lutein and zeaxanthin modulate the inflammatory response. Similar mechanisms may explain salutary effects of lutein and zeaxanthin in reducing the risk for AMD.
    Free Radical Biology and Medicine 06/2012; 53(6):1298-307. DOI:10.1016/j.freeradbiomed.2012.06.024
  • Source
    • "Indeed, histological studies have consistently demonstrated the presence of chronic inflammatory cells in retinas afflicted with AMD [61] [62]. It is believed that these inflammatory cells damage tissue by releasing proteolytic enzymes and oxidants, thus compounding oxidative stress. "
    [Show abstract] [Hide abstract]
    ABSTRACT: There is a consensus that age-related macular degeneration (AMD) is the result of (photo)-oxidative-induced retinal injury and its inflammatory sequelae, the latter being influenced by genetic background. The dietary carotenoids, lutein (L), zeaxanthin (Z), and meso-zeaxanthin (meso-Z), accumulate at the macula, where they are collectively known as macular pigment (MP). The anatomic (central retinal), biochemical (anti-oxidant) and optical (short-wavelength-filtering) properties of this pigment have generated interest in the biologically plausible rationale that MP may confer protection against AMD. Level 1 evidence has shown that dietary supplementation with broad-spectrum anti-oxidants results in risk reduction for AMD progression. Studies have demonstrated that MP rises in response to supplementation with the macular carotenoids, although level 1 evidence that such supplementation results in risk reduction of AMD and/or its progression is still lacking. Although appropriately weighted attention should be accorded to higher levels of evidence, the totality of available data should be appraised in an attempt to inform professional practice. In this context, the literature demonstrates that supplementation with the macular carotenoids is probably the best means of fortifying the anti-oxidant defences of the macula, thus putatively reducing the risk of AMD and/or its progression.
    Molecular Nutrition & Food Research 02/2012; 56(2):270-86. DOI:10.1002/mnfr.201100219
Show more