Browsing by Author "Acar, Ozge Karabiyik"

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Citation Count: 0
ALGINATE-BASED CELL ENCAPSULATION USING DIFFERENT CROSSLINKER ELEMENTS
(World Scientific Publ Co Pte Ltd, 2024) Acar, Özge; Tuncer, A. Alperen; Sahin, Fikrettin; Kose, Gamze Torun; Aysan, Erhan; Genetik ve Biyomühendislik / Genetic and Bio-Engineering
Alginate microcapsules are the most frequently used materials for cell transplantation. Different crosslinkers affect crosslinking affinity, which has a significant influence on microcapsule properties. The objective was to prepare in vitro microcapsules using calcium, barium, iron, manganese, nickel, and strontium as divalent cations to observe their potential for use in cell transplantation. Sodium alginate was added dropwise to the individually prepared crosslinkers to observe diffusion-based gelling. Alginate microcapsules were investigated regarding capsule stability, physiological properties, and cell viability. After 30 days of incubation, cell viability was greater than 90% for the cell-encapsulated microcapsules when crosslinked with CaCl2 and NiCl2. Viability decreased in the following order: CaCl2 > NiCl2 > BaCl2 > SrCl2 > MnCl2 > FeCl2. A compression test was performed to investigate the required force to deform 30% of microcapsules, and only MnCl2, FeCl2 (180mM), and NiCl2 (50mM) demonstrated higher resistance to the applied force than CaCl2. Except for the FeCl2 group, all cell-encapsulated microcapsules remained intact for 45 days. Potential sensitivities to CaCl2 during cell transplantation may compel alternative crosslinker usage, and our study revealed that NiCl2 and BaCl2 can be used as alternative crosslinkers to CaCl2 due to their high cell viability and consistent stability.
Citation Count: 1
Combined approaches for detecting polypropylene microplastics in crop plants
(Academic Press Ltd- Elsevier Science Ltd, 2023) Acar, Özge; Unek, Ceren; Sut, Pinar Akkus; Acar, Ozge Karabiyik; Yurtsever, Meral; Sahin, Fikrettin; Genetik ve Biyomühendislik / Genetic and Bio-Engineering
Microplastics (MPs) pollution in the terrestrial environment causes accumulation in crop plants. Consumption of these plants may have negative effects on human health. Therefore, it is crucial to analyze MPs accumulation in the plants. The aim of this study is to determine polypropylene (PP) particles in plants exposed to label-free PP for 75 days. In order to extract PP from organic matter, a two-step alkaline and wet peroxide oxidation chemical digestion method was applied to the roots, stems, and leaves of maize and wheat. The PP particles in the digested solutions were detected by the Nile red staining method, which has not been used previously in the detection of MPs in plants. Nile red stained PP particles mostly accumulated in the roots of wheat and the stems of maize plants. Statistical analysis revealed that the maize deposited more and larger PP particles regardless of the location. Moreover, the presence of PP particles in the digestion solutions was proved by the heating method. The PP particles on the glass slides were transformed into different shapes due to melting.
Citation Count: 0
Computational drug repurposing for primary hyperparathyroidism
(Elsevier Ireland Ltd, 2024) Oktem, Elif Kubat; Yazar, Metin; Acar, Özge; Acar, Ozge Karabiyik; Genetik ve Biyomühendislik / Genetic and Bio-Engineering
In hyperparathyroidism (hyperPTH), excessive amounts of PTH are secreted, interfering with calcium regulation in the body. Several drugs can control the disease's side effects, but none of them is an alternative treatment to surgery. Therefore, new drug candidates are necessary. In this study, three computationally repositioned drugs, DG 041, IMD 0354, and cucurbitacin I, are evaluated in an in vitro model of hyperPTH. First, we integrated publicly available transcriptomics datasets to propose drug candidates. Using 3D spheroids derived from a single primary hyperPTH patient, we assessed their in vitro efficacy. None of the proposed drugs affected the viability of healthy cell control (HEK293) or overactive parathyroid cells at the level of toxicity. This behavior was attributed to the non-cancerous nature of the parathyroid cells, establishing the hyperPTH disease model. Cucurbitacin I and IMD 0354 exhibited a slight inverse relationship between increased drug concentrations and cell viability, whereas DG 041 increased viability. Based on these results, further studies are needed on the mechanism of action of the repurposed drugs, including determining the effects of these drugs on cellular PTH synthesis and secretion and on the metabolic pathways that regulate PTH secretion.
Citation Count: 0
EFFECT OF DIFFERENT SODIUM ALGINATE COMPOSITIONS ON 3D MICROCAPSULE STRUCTURE AND CELL VIABILITY
(World Scientific Publ Co Pte Ltd, 2024) Acar, Özge; Nozhatzadeh, G. Delal; Tuncer, A. Alperen; Kose, Gamze Torun; Aysan, Erhan; Genetik ve Biyomühendislik / Genetic and Bio-Engineering
Despite the constant expansion of the global alginate market and the emergence of a plethora of new brands to meet the rising demand, the literature remains insufficient for the selection and preparation of optimized microcapsules. In this study, the cell transplantation potentials of two commercial alginate brands (Sigma and FMC Biopolymers-PRONATAL) with different M/G ratios were compared in vitro. Different brands of alginates were crosslinked with increasing concentrations of calcium chloride (1.5%, 2%, and 3%w/v). Utilizing size/dimension measurements, compression, swelling, and degradation tests, scanning electron microscopy (SEM), and bright field (BF) imaging, the intrastructure of each experimental group was investigated. Moreover, the cell viability of HDF-encapsulated Ca-alginate microcapsules was evaluated. According to SEM and compression analysis, PROTANAL KF200 with a lower M/G ratio was found to be more rigid and robust. Due to the different proportions of MM and GG blocks, Sigma Ca-alginate microcapsules exhibited greater flexibility but lower hardness than PRONATAL KF200 microcapsules. However, there was no significant difference in cell viability between the alginate microcapsules. In future in vivo experiments, encouraging cell transplantation outcomes could be monitored by the choice of PROTANAL KF200 sodium alginate polymer for the microcapsule preparation.
Citation Count: 0
Optimizing decellularization protocols for human thyroid tissues: a step towards tissue engineering and transplantation
(Iop Publishing Ltd, 2024) Acar, Özge; Bozdag, Gulnihal; Hacihasanoglu, Ezgi; Tuncer, A. Alperen; Aysan, Erhan; Kose, Gamze Torun; Genetik ve Biyomühendislik / Genetic and Bio-Engineering
Hypothyroidism is caused by insufficient stimulation or disruption of the thyroid. However, the drawbacks of thyroid transplantation have led to the search for new treatments. Decellularization allows tissue transplants to maintain their biomimetic structures while preserving cell adhesion, proliferation, and differentiation. This study aimed to decellularize human thyroid tissues using a structure-preserving optimization strategy and present preliminary data on recellularization. Nine methods were used for physical and chemical decellularization. Quantitative and immunohistochemical analyses were performed to investigate the DNA and extracellular matrix components of the tissues. Biomechanical properties were determined by compression test, and cell viability was examined after seeding MDA-T32 papillary thyroid cancer (PTC) cells onto the decellularized tissues. Decellularized tissues exhibited a notable decrease (<50 ng mg(-1) DNA, except for Groups 2 and 7) compared to the native thyroid tissue. Nonetheless, collagen and glycosaminoglycans were shown to be conserved in all decellularized tissues. Laminin and fibronectin were preserved at comparatively higher levels, and Young's modulus was elevated when decellularization included SDS. It was observed that the strain value in Group 1 (1.63 +/- 0.14 MPa) was significantly greater than that in the decellularized tissues between Groups 2-9, ranging from 0.13 +/- 0.03-0.72 +/- 0.29 MPa. Finally, viability assessment demonstrated that PTC cells within the recellularized tissue groups successfully attached to the 3D scaffolds and sustained metabolic activity throughout the incubation period. We successfully established a decellularization optimization for human thyroid tissues, which has potential applications in tissue engineering and transplantation research. Our next goal is to conduct recellularization using the methods utilized in Group 1 and transplant the primary thyroid follicular cell-seeded tissues into an in vivo animal model, particularly due to their remarkable 3D structural preservation and cell adhesion-promoting properties.
Citation Count: 2
Production of parathyroid-like cells from thyroid stem cells in co-culture environment
(Lippincott Williams & Wilkins, 2022) Acar, Özge; Nozhatzadeh, Gulcin Delal; Tuncer, Alperen; Kose, Gamze Torun; Hacihasanoglu, Ezgi; Sahin, Fikrettin; Aysan, Erhan; Genetik ve Biyomühendislik / Genetic and Bio-Engineering
Background:Parathyroid-like cells were aimed to be developed using cells isolated from thyroid since their embryological origins are the same. Method:Activin A and sonic hedgehog (Shh) are the proteins used in differentiation (dif) medium. Parathyroid and thyroid cells were cultured in a 3-dimensional environment and divided into five groups: thyroid standard (st) medium, thyroid dif medium, parathyroid st medium, thyroid-parathyroid co-culture st medium, and thyroid-parathyroid co-culture dif medium. Throughout 28 days of incubation, groups were investigated by carrying out the live dead assay, confocal microscopy, real-time PCR, immunohistochemistry and biochemical assays. Results:Thyroid-parathyroid co-culture cells grown in dif medium exhibited upregulated expressions of parathormone (PTH) (5.1-fold), PTH1R (3.6-fold), calcium sensing receptor (CaSR) (8.8-fold), and loss of thyroid-specific thyroid transcription factor 1 (TTF1) expression when compared to the thyroid st medium group. PTH secretion decreased by 35% in the parathyroid st medium group and 99.9% in the thyroid-parathyroid co-culture st medium group but decreased only 3.5% in the thyroid-parathyroid co-culture dif medium group on day 28. Conclusion:Using Activin A and Shh proteins, thyroid stem/progenitor cells were differentiated to parathyroid-like cells successfully in a co-culture environment. A potentially effective novel method for cell differenatiation is co-culture of cells having the same embryological origin.