Evaluation of aquaporin4 (AQP4)-related miRNAas in alzheimer's disease (AD) and glaucoma

Title: Evaluation of aquaporin4 (AQP4)-related miRNAs in Alzheimer's disease (AD) and glaucoma. Aim: In this thesis study, the potential of AQP4 as a biomarker for AD and glaucoma was investigated by evaluating AQP4-related miRNAs, AQP4 mRNA expression and protein levels, which are involved in the functioning of the glymphatic system in AD and glaucoma, in tear and conjunctival impression cytology samples. Methods: Analysis of AQP4 gene ve related miRNA expression profiles ve AQP4 protein levels in the tear samples of patients, who are followed up for glaucoma in Eskişehir Osmangazi University (ESOGU) Faculty of Medicine, Department of Ophthalmology and diagnosed with AD in Neurology Department and control groups, were investigated by RT-PCR ve ELISA tests. Immunohistochemical analyzes of conjunctival impression cytology samples were evaluated by using semi-quantitative methods (H-score). Results: There was no significant difference between AD, glaucoma and control groups in terms of AQP4 mRNA, AQP4 protein levels in tear samples ve H-score of AQP4 immune positive cells in conjunctival impression cytology samples. On the other hand, there was a significant increase in the expression levels of all miRNAs examined, except for miR-320a, in tear samples of Alzheimer's patients. Among the six discriminative miRNAs in Alzheimer's patients, the highest levels of them were miR-140-5p, miR145-5p ve miR-29-3p with sensitivity ve specificity of 93.75% ve 50%; 68.75% ve 93.75%; 68.75% ve 87.50%, respectively. MiRNA levels in glaucoma patients were not different from the control group. In the glaucoma group, the sensitivity and specificity of only miR-145-5p were found significant (68.75% ve 68.75%). AD group differed from glaucoma in terms of expression of mir-320a, miR130a, miR-224, miR-145, 196b-5p ve miR-29a-3p, miR-140-5p, but only miR-140-5p from the control group. Conclusions: In tears samples of the patients, while six of the examined AQP4-related miRNAs displayed correlation with AD, one of them showed with glaucoma, and AQP4 seems not to have the potential as a common biomarker for AD and glaucoma.