Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Epigallocatechin Gallate and Punicalagin Combination Reduces Aβ Aggregation and Promotes Neurogenesis in Adult Zebrafish Brain(John Wiley and Sons Inc, 2026) Nazli, D.; Ipekgil, D.; Poyraz, Y.K.; Can, K.; Okmen, I.; Turhanlar-Sahin, E.; Ozhan, G.Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline, memory impairment, and behavioral alterations. The pathogenesis of AD involves the accumulation of amyloid-beta (Aβ) plaques and the hyperphosphorylated tau proteins, which disrupt neuronal function and trigger neuroinflammation. This study explores the therapeutic potential of epigallocatechin gallate (EGCG) and punicalagin (PU) in mitigating Aβ-induced toxicity using an adult zebrafish model of AD. Our results demonstrate that the EGCG + PU combination significantly reduces Aβ accumulation, protects against cellular damage, suppresses acetylcholinesterase (AChE) activity, and normalizes the expression of amyloidogenic and AD-related genes. Additionally, EGCG + PU treatment alleviates neuroinflammation by suppressing glial activation, including reductions in L-plastin and proinflammatory cytokine expression, while promoting neuronal recovery through mechanisms of neurogenesis and neuroprotection. Notably, the combination treatment restored neuronal density and improved behavioral outcomes by alleviating anxiety- and aggression-like behaviors associated with Aβ toxicity. These results underscore the synergistic neuroprotective effects of EGCG + PU, highlighting their potential as a novel therapeutic approach for mitigating the pathological, behavioral, and inflammatory aspects of AD. © 2026 Wiley Periodicals LLC.Article Citation - WoS: 2Citation - Scopus: 2Tuning Toxicity Profiles of Graphene Oxide Through Imidazole-Oxime Modification: Zebrafish as a Model System(Oxford Univ Press, 2025) Yildirim, Serkan; Kokturk, Mine; Yigit, Aybek; Sahin, Ayse; Kiliclioglu, Metin; Atamanalp, Muhammed; Alak, GoncaThe increasing use of nanotechnology, especially in agriculture and the food industry, has raised concerns about the possible adverse effects of nanomaterials (NMs) on human health and the environment. This study investigates the effects of synthesized graphene oxide (GO) and its derivatives on zebrafish exposed for 96 hr, focusing on morphological changes in brain tissue, histopathology, and immunofluorescent markers such as 8-hydroxy-2'-deoxyguanosine (8-OHdG) and nucleolar protein 10 (NOP10). Exposure to GO resulted in malformations, DNA damage, and increased NOP10 expression, and it reduced hatching and survival rates. Our results demonstrated that exposure to GO, graphene oxide-oxime (GO-OX), and OX exerted dose-dependent inhibitory effects on hatching and promoted malformations in zebrafish larvae. Histopathological analysis revealed that higher doses led to more pronounced tissue damage, with GO 50 causing severe degeneration and necrosis, while high doses of GO-OX and OX resulted in moderate tissue changes. This was further supported by the increased expression levels of 8-OHdG (marker of oxidative DNA damage) and NOP10 (marker of nucleolar stress), which aligns with the histopathological findings and confirms the neurotoxic effects. Notably, GO-OX treatments consistently mitigated both morphological and neurotoxic effects at all doses, suggesting that oxime functionalization reduces the inherent toxicity of GO. In contrast, treatment with different concentrations of GO-OX derivatives mitigated these adverse effects, reducing them to mild or moderate levels.Review Citation - Scopus: 2Wnt/β-catenin Signaling in Central Nervous System Regeneration(2025) Nazli, D.; Bora, U.; Ozhan, G.The Wnt/β-catenin signaling pathway plays a pivotal role in the development, maintenance, and repair of the central nervous system (CNS). This chapter explores the diverse functions of Wnt/β-catenin signaling, from its critical involvement in embryonic CNS development to its reparative and plasticity-inducing roles in response to CNS injury. We discuss how Wnt/β-catenin signaling influences various CNS cell types-astrocytes, microglia, neurons, and oligodendrocytes-each contributing to repair and plasticity after injury. The chapter also addresses the pathway's involvement in CNS disorders such as Alzheimer's and Parkinson's diseases, psychiatric disorders, and traumatic brain injury (TBI), highlighting potential Wnt-based therapeutic approaches. Lastly, zebrafish are presented as a promising model organism for studying CNS regeneration and neurodegenerative diseases, offering insights into future research and therapeutic development. © 2024. The Author(s), under exclusive license to Springer Nature Switzerland AG.Article Citation - WoS: 1Citation - Scopus: 2<i>tubg1</I> Somatic Mutants Show Tubulinopathy-Associated Neurodevelopmental Phenotypes in a Zebrafish Model(Springer, 2024) Cark, Ozge; Katkat, Esra; Aydogdu, Ipek; Iscan, Evin; Oktay, Yavuz; Ozhan, GunesDevelopment of the multilayered cerebral cortex relies on precise orchestration of neurogenesis, neuronal migration, and differentiation, processes tightly regulated by microtubule dynamics. Mutations in tubulin superfamily genes have been associated with tubulinopathies, encompassing a spectrum of cortical malformations including microcephaly and lissencephaly. Here, we focus on gamma-tubulin, a pivotal regulator of microtubule nucleation encoded by TUBG1. We investigate its role in brain development using a zebrafish model with somatic tubg1 mutation, recapitulating features of TUBG1-associated tubulinopathies in patients and mouse disease models. We demonstrate that gamma-tubulin deficiency disrupts neurogenesis and brain development, mirroring microcephaly phenotypes. Furthermore, we uncover a novel potential regulatory link between gamma-tubulin and canonical Wnt/beta-catenin signaling, with gamma-tubulin deficiency impairing Wnt activity. Our findings provide insights into the pathogenesis of cortical defects and suggest that gamma-tubulin could be a potential target for further research in neurodevelopmental disorders, although challenges such as mode of action, specificity, and potential side effects must be addressed.Article Citation - WoS: 6Citation - Scopus: 6A Novel 2-Aminophenalenone Fluorescent Probe Designed for Monitoring H2o2 for in Vitro and in Vivo Bioimaging(Elsevier, 2024) Saygılı, Ecem; Ersöz Gülseven, Esra; Kıbrıs, Erman; Çakan Akdoğan, Gülçin; Üçüncü, MuhammedA significant compound in living organisms, hydrogen peroxide (H2O2) plays a dual role as a signalling molecule in cellular communication and as a pivotal biomarker in assessing disease and oxidative stress. Thus, the detection of abnormal changes in H2O2 levels is essential to understanding its function and involvement in biological systems. The growing demand to meet the specific needs for applications, particularly in biological systems, has sharpened focus on highly sensitive, highly selective molecular sensors and, in turn, heightened interest in these diagnostic tools with innovative designs. In our study, 2-aminophenalenone (2-AP) was used for the first time as a fluorophore in a fluorescent probe. The 2-APB molecule obtained from the reaction of 2-AP with 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) benzyl chloroformate exhibited a highly selective and sensitive (i.e. 62 nM) detection profile for H2O2 compared with the other reactive oxygen species, anions, and metal cations. Moreover, offering naked-eye detection in aqueous solutions, 2-APB demonstrated excellent sensing performance, detection and real-time monitoring in relation to exogenous H2O2 in cells and endogenous H2O2 in zebrafish embryos. © 2024 Elsevier B.V.Article Citation - WoS: 12Citation - Scopus: 13Lc-esi-ms/Ms Analysis of Secondary Metabolites of Different St. John's Wort (hypericum Perforatum) Extracts Used as Food Supplements and Evaluation of Developmental Toxicity on Zebrafish (danio Rerio) Embryos and Larvae(Elsevier, 2023) Atalar, Mehmet Nuri; Köktürk, Mine; Altındağ, Fikret; Özhan, Güneş; Özen, Tevfik; Demirtaş, İbrahim; Gülçin, İlhamiHypericum perforatum (St. John's wort) belongs to the Hypericaceae family and is one of the best known Hypericum species worldwide. It is a very popular and valuable medicinal plant widely distributed in Anatolia. Hypericum perforatum contains many bioactive components that play a role in activities has been used as a food supplement. The extracts are used within safe dose range that are harmless and effective for health. When the SJW1, SJW2 and SJW3 fractions of St. John's Wort extracts were exposed to zebrafish embryos and larvae at different concentrations (5, 10, 100, and 300 µg/mL), the survival rates at 96th hour were determined as 83.3, 27.5 and 2.5%, respectively. No significant changes were found in the malformation rates, and the larval emergence was found to be above 80% at 96th hour for all extracts. No caspase-3 expression was found at the 96th hour in the larvae. Similar secondary components of extracts were observed except quantitative differences. The use of samples in doses of 10 µg/mL and below as food supplement may be harmless, however, threshold dose values of H. perforatum extracts lower toxic doses may be due to the different amounts of secondary metabolites. © 2023