Anti-CRYAA monoclonal antibody, clone 2I4.C9

Purpose: Pseudoexfoliation (PEX) syndrome is an age-related progressive disease of the extracellular matrix with ocular manifestations. PEX is clinically diagnosed by the presence of extracellular exfoliative deposits on the anterior surface of the ocular lens. PEX syndrome is a major risk factor for developing glaucoma the leading cause of irreversible blindness in the world and is often associated with the development of cataract. PEX reportedly coexists with Alzheimer disease and increases the risk of heart disease and stroke. PEX material deposited on the anterior surface of the ocular lens is highly proteinaceous complex and insoluble making deciphering the protein composition of the material challenging. Thus to date only a small proportion of the protein composition of PEX material is known. The aim of this study was to decipher the protein composition of pathological PEX material deposited on the ocular lens in patients and advance the understanding of pathophysiology of PEX syndrome. Methods: Liquid-chromatography and tandem mass spectrometry (LC-MS/MS) was employed to discover novel proteins in extracts of neat PEX material surgically isolated from patients (n = 4) with PEX syndrome undergoing cataract surgery. A sub-set of the identified proteins was validated with immunohistochemistry using lens capsule specimens from independent patients (n=3) lens capsules from patients with cataract but without PEX syndrome were used as controls (n=4). Expression of transcripts of the validated proteins in the human lens epithelium was analyzed with reverse transcription PCR (RT-PCR). Functional relationships among the proteins identified in this study and genes and proteins previously implicated in the disease were bioinformatically determined using InnateDB. Results: Peptides corresponding to 66 proteins including ten proteins previously known to be present in PEX material were identified. Thirteen newly identified proteins were chosen for validation. Of those proteins 12 were found to be genuine components of the material. The novel protein constituents include apolipoproteins (APOA1 and APOA4) stress response proteins (CRYAA and PRDX2) and blood-related proteins (fibrinogen and hemoglobin subunits) including iron-free hemoglobin. The gene expression data suggest that the identified stress-response proteins and hemoglobin are contributed by the lens epithelium and apolipoproteins and fibrinogen by the aqueous humor to the PEX material. Pathway analysis of the identified novel protein constituents and genes or proteins previously implicated in the disease reiterated the involvement of extracellular matrix organization and degradation elastic fiber formation and complement cascade in PEX syndrome. Network analysis suggested a central role of fibronectin in the pathophysiology of the disease. The identified novel protein constituents of PEX material also shed light on the molecular basis of the association of PEX syndrome with heart disease stroke and Alzheimer disease. Conclusions: This study expands the understanding of the protein composition of pathological PEX material deposited on the ocular lens in patients with PEX syndrome and provides useful insights into the pathophysiology of this disease. This study together with the previous study by our group (Sharma et al. Experimental Eye Research 2009;89(4):479-85) demonstrate that using neat PEX material devoid of the underlying lens capsule for proteomics analysis is an effective approach for deciphering the protein composition of complex and highly insoluble extracellular pathological ocular deposits present in patients with PEX syndrome.

Background: Alpha A-crystallin (CRYAA) is considered critical for the maintenance of lens transparency and is related to the pathogenesis of age-related cataracts (ARCs), especially the nuclear subtype. As the 5' untranslated region (5' UTR) modulates gene expression, the purpose of current study was to investigate whether single nucleotide polymorphisms (SNPs) in the 5' UTR of CRYAA were associated with susceptibility to ARC in a Han Chinese population and to clarify the mechanism of this association. Methods: SNPs in the 5' UTR (-1 to -1000) of CRYAA were identified in 243 nuclear ARC patients and 263 controls using polymerase chain reaction and DNA sequencing. Allele and genotype frequencies were calculated and compared between two groups. Haploview 4.2 was used to calculate the linkage disequilibrium index, and the SHEsis analysis platform was used to infer haplotype construction. A dual-luciferase reporter gene assay was used for transcription of CRYAA in the presence of a protective haplotype with individual SNP alteration, Chromatin immunoprecipitation (ChIP) was employed to determine whether SNPs regulated CRYAA expression by altering the binding affinity of transcription factors. Results: Three polymorphisms were identified in the 5' UTR of CRYAA: rs3761381 (P = 0.000357, odds ratio [ OR] = 1.837), rs13053109 (P = 0.788, OR = 1.086), and rs7278468 (P = 0.00136, OR = 0.652). The haplotype C-G-T (P = 0.0014, OR = 1.536) increased the risk of nuclear ARC, whereas the haplotype T-G-G (P = 0.00029, OR = 0.535) decreased the risk. The haplotype C-G-T decreased CRYAA transcription through rs7278468, which is located in the binding site of specificity protein 1 (Sp1). Furthermore, the G allele of rs7278468 increased CRYAA transcription by enhancing the binding affinity of Sp1. Conclusions: These data indicate that the CRYAA polymorphism is a genetic marker of inter-individual differences in the risk of nuclear ARC.