Differential Expression of Complement Markers in Normal and AMD Transmitochondrial Cybrids

• Published in: PloS one Vol. 11; no. 8; p. e0159828
• Main Authors: Nashine, Sonali, Chwa, Marilyn, Kazemian, Mina, Thaker, Kunal, Lu, Stephanie, Nesburn, Anthony, Kuppermann, Baruch D., Kenney, M. Cristina
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 03.08.2016; Public Library of Science (PLoS)
• Subjects: Abnormalities; Adult; Aged; Aged, 80 and over; Biology and Life Sciences; Biomarkers - metabolism; Case-Control Studies; Cells, Cultured; Complement; Complement inhibitors; Complement Pathway, Classical - genetics; Complement System Proteins - genetics; Complement System Proteins - metabolism; Cybrids; Deoxyribonucleic acid; DNA; DNA methylation; DNA, Mitochondrial - genetics; Energy Metabolism; Female; Gene expression; Gene Expression Profiling; Gene Expression Regulation; Genes; Genome, Mitochondrial; Genomes; Humans; Hybrid Cells - metabolism; Macular degeneration; Macular Degeneration - genetics; Macular Degeneration - metabolism; Male; Markers; Medicine and Health Sciences; Middle Aged; Mitochondria; Mitochondria - genetics; Mitochondria - metabolism; Mitochondrial DNA; Nuclei; Pathogenesis; Platelets; Retina; Retrograde transport; Signal transduction; Signal Transduction - genetics; Signaling; Western blotting; United States > US; California; Nevada
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0159828

Variations in mitochondrial DNA (mtDNA) and abnormalities in the complement pathways have been implicated in the pathogenesis of age-related macular degeneration (AMD). This study was designed to determine the effects of mtDNA from AMD subjects on the complement pathway. Transmitochondrial cybrids were prepared by fusing platelets from AMD and age-matched Normal subjects with Rho0 (lacking mtDNA) human ARPE-19 cells. Quantitative PCR and Western blotting were performed to examine gene and protein expression profiles, respectively, of complement markers in these cybrids. Bioenergetic profiles of Normal and AMD cybrids were examined using the Seahorse XF24 flux analyzer. Significant decreases in the gene and protein expression of complement inhibitors, along with significantly higher levels of complement activators, were found in AMD cybrids compared to Older-Normal cybrids. Seahorse flux data demonstrated that the bioenergetic profiles for Older-Normal and Older-AMD cybrid samples were similar to each other but were lower compared to Young-Normal cybrid samples. In summary, since all cybrids had identical nuclei and differed only in mtDNA content, the observed changes in components of complement pathways can be attributed to mtDNA variations in the AMD subjects, suggesting that mitochondrial genome and retrograde signaling play critical roles in this disease. Furthermore, the similar bioenergetic profiles of AMD and Older-Normal cybrids indicate that the signaling between mitochondria and nuclei are probably not via a respiratory pathway.