Browsing by Author "Sahin, Betul"

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Neonatal Neurodegeneration in Alzheimer's Disease Transgenic Mouse Model
(IOS PRESS, 2018-01-01) Mazi, Aise Rumeysa; Arzuman, Aysegul Sumeyye; Gurel, Busra; Sahin, Betul; Tuzuner, Mete Bora; Ozansoy, Mehmet; Baykal, Ahmet Tarik
Alzheimer's disease (AD) is a progressive disorder characterized by a variety of molecular pathologies causing cortical dementia with a prominent memory deficit. Formation of the pathology, which begins decades before the diagnosis of the disease, is highly correlated with the clinical symptoms. Several proteomics studies were performed using animal models to monitor the alterations of the brain tissue proteome at different stages of AD. However, proteome changes in the brain regions of newborn transgenic mouse model have not been investigated yet. To this end, we analyzed protein expression alterations in cortex, hippocampus and cerebellum of transgenic mice carrying five familial AD mutations (5XFAD) at neonatal day-1. Our results indicate a remarkable difference in protein expression profile of newborn 5XFAD brain with region specific variations. Additionally, the proteins, which show similar expression alteration pattern in postmortem human AD brains, were determined. Bioinformatics analysis showed that the molecular alterations were mostly related to the cell morphology, cellular assembly and organization, and neuroinflammation. Moreover, morphological analysis revealed that there is an increase in neurite number of 5XFAD mouse neurons in vitro. We suggest that, molecular alterations in the AD brain exist even at birth, and perhaps the disease is silenced until older ages when the brain becomes vulnerable.
Proteins associated with neutrophil degranulation are upregulated in nasopharyngeal swabs from SARS-CoV-2 patients
(PUBLIC LIBRARY SCIENCE, 2020-01-01) Akgun, Emel; Tuzuner, Mete Bora; Sahin, Betul; Kilercik, Meltem; Kulah, Canan; Cakiroglu, Hacer Nur; Serteser, Mustafa; Unsal, Ibrahim; Baykal, Ahmet Tarik
COVID-19 or severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) appeared throughout the World and currently affected more than 9 million people and caused the death of around 470,000 patients. The novel strain of the coronavirus disease is transmittable at a devastating rate with a high rate of severe hospitalization even more so for the elderly population. Naso-oro-pharyngeal swab samples as the first step towards detecting suspected infection of SARS-CoV-2 provides a non-invasive method for PCR testing at a high confidence rate. Furthermore, proteomics analysis of PCR positive and negative naso-oropharyngeal samples provides information on the molecular level which highlights disease pathology. Samples from 15 PCR positive cases and 15 PCR negative cases were analyzed with nanoLC-MS/MS to identify the differentially expressed proteins. Proteomic analyses identified 207 proteins across the sample set and 17 of them were statistically significant. Protein-protein interaction analyses emphasized pathways like Neutrophil degranulation, Innate Immune System, Antimicrobial Peptides. Neutrophil Elastase (ELANE), Azurocidin (AZU1), Myeloperoxidase (MPO), Myeloblastin (PRTN3), Cathepsin G (CTSG) and Transcobalamine-1 (TCN1) were found to be significantly altered in naso-oropharyngeal samples of SARS-CoV-2 patients. The identified proteins are linked to alteration in the innate immune system specifically via neutrophil degranulation and NETosis.
Proteomics analysis of mitochondrial dysfunction triggered by complex specific electron transport chain inhibitors reveals common pathways involving protein misfolding in an SH-SY5Y in vitro cell model
(TUBITAK SCIENTIFIC \& TECHNICAL RESEARCH COUNCIL TURKEY, 2017-01-01) Sahin, Betul; Baykal, Ahmet Tarik
Mitochondrial dysfunction has been previously identified in neurodegenerative diseases such as Alzheimer disease, Huntington disease, and Parkinson disease. Chemical inhibition of the mitochondrial electron transport chain (ETC) was shown to trigger symptoms in animal models similar to those observed in human neurodegenerative diseases. In order to understand the effect of mitochondrial dysfunction on the proteome level, LC-MSE-based bottom-up, label-free differential proteomics expression analysis was used to monitor protein level changes in SH-SY5Y neuroblastoma cells induced by ETC-specific inhibitors (MPTP, 3-NP, sodium azide, antimycin A, and oligomycin). A total of 379 proteins were identified across the sample set and 75 of them were found to be differentially expressed (>30\% fold change). Complex-specific inhibition of the five ETS complexes were expected to result in the aberrant regulation of different molecular pathways, but the bioinformatics analysis of the LC-MSMS data showed that the differentially expressed proteins were mostly involved in similar metabolic processes. The findings suggest that the complex-specific alterations may not be directly linked to neurodegenerative pathways, but could be considered contributors. Moreover, the proteins that showed the highest protein expression difference (>60\% fold change) are involved in pathways regarding protein-folding and response to unfolded proteins. The results indicate that protein misfolding pathways might have a central role in the genesis and progression of neurodegenerative diseases and that label-free LC-MSMS proteomics analysis is an invaluable approach for studying of molecular pathways in neurodegeneration.