Pathomechanisms of native tear protein complexes in dry eye syndrome
Biochemistry
Final Report Abstract
This project characterized the native tear proteome and elucidated the intricate regulation of signaling pathways underlying the pathomechanistic changes in dry eye syndrome (DES) patients. We provided the first experimental evidence of the complex interplay of eight novel supramolecular protein complexes in human tears, including the first report of a megadaltonscale complex (CI, 1050 kDa). Notably, CI-associated proteins were significantly lower in abundance in the combined evaporative and aqueous-deficient DES (DRYaqlip) compared to the healthy (CTRL) and reflex groups, demonstrating a disruption in tear film homeostasis. These are predominantly lacrimal-specific proteins (e.g., IGHA1, PRR4, LACRT, PROL1, PIGR), which were significantly enriched in antibacterial response, dry eye, and tear secretion. Conversely, a cluster of significantly high abundant proteins in DRYaqlip vs. CTRL were associated with <250 kDa complexes (CIV–CVIII), which exhibited intricate interactions and enriched functions in inflammation, metabolism, oxidative stress, and cytoskeletal organization. We also analyzed the largest tear sample cohort to date (N=322) employing the clinical proteomics strategy to analyze inter-individual proteome alterations and their correlations to various clinical attributes i.e. age, basic secretory test (BST), tear break-up time, ocular surface disease index, visual analog scale and body mass index. A key finding was the identification of 36 proteins (e.g. LTF, LYZ, LCN1, LACRT, PROL1, PRR4, ZG16B), which were correlated negatively with age and positively with BST, suggesting an agerelated decline in tear production and antimicrobial defense. Conversely, 307 proteins annotated to cytoskeletal organization, apoptosis, inflammation, autophagy, and protein metabolism showed the opposite trend. The trends in BST and age aligned with CI impairment, characterized by decreased secretory proteins and elevated CIV–CVIII complexes. Finally, we identified two PRR4 peptide isoforms, a potential marker for CI, as promising therapeutic candidates with protective effects in a human corneal epithelial cell culture DES model. These PRR4 isoforms demonstrated significant anti-inflammatory, antiapoptotic, and anti-oxidative stress properties, providing a foundation for synthetic peptidebased eye drops as a potential therapeutic strategy to restore ocular surface homeostasis in DES. In summary, this study provided a comprehensive insight into the functional roles of the native tear proteome in maintaining tear film homeostasis and identified clinical markers with significant correlation with specific clinical attributes. These findings bridge the native molecular discoveries with clinical insights, laying the foundation for improved diagnosis and prognosis of DES. Notably, PRR4-derived peptides introduce a first-of-its-kind therapeutic strategy, paving the way for innovative treatment options to improve DES patient outcomes and quality of life.
Publications
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Characterization of the proteome changes in an in vitro hyperosmotic dry eye model employing human corneal epithelial cells. Acta Ophthalmologica, 102(S279).
Lin, Hao; Manicam, Caroline; Pfeiffer, Norbert; Grus, Franz & Perumal, Natarajan
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Clinical proteomics elucidated the complex molecular mechanisms in the progression of dry eye syndrome with different severity levels: A step forward to personalized diagnosis. 23rd Human Proteome Organization World Congress (HUPO2024), 20th-24th September 2024, Dresden, Germany
Perumal, N., Lindner, A., Glassmacher, A., Multani, B., Francis, P.J. & Manicam, C.
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Impairment of Native Supramolecular Protein Complexes in Tears: A Novel Phenomenon in Dry Eye Syndrome. The Association for Research in Vision and Ophthalmology (ARVO) Annual Meeting on “Vision for the Future”, 5th-9th May 2024, Seattle, Washington, USA
Perumal, N., Acharya S., Francis, A.F.P.J., Pfeiffer, N., Grus, F. & Manicam, C.
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Novel pathomechanisms of impairment of native tear protein complexes in aqueous deficient dry eye syndrome. Acta Ophthalmologica, 102(S279).
Perumal, Natarajan; Hering, Janine; Pfeiffer, Norbert; Grus, Franz & Manicam, Caroline
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The role of exocytotic proteins in the (dys)regulation of human reflex tearing and aqueous‐deficient dry eye syndrome. Acta Ophthalmologica, 102(S279).
Francis, Alfred Francis Pakkam John; Manicam, Caroline; Neumann, Fabian; Pfeiffer, Norbert; Grus, Franz & Perumal, Natarajan
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Identification of clinical protein markers correlated to the impairment of the lacrimal and meibomian glands in the progression of dry eye syndrome. Acta Ophthalmologica, 103(S284).
Perumal, Natarajan; Lindner, Anna; Glassmacher, Adina; Multani, Bettina; Lin, Hao & Manicam, Caroline
