Browsing by Author "Acar, Mustafa Burak"

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Progression of irradiated mesenchymal stromal cells from early to late senescence: Changes in SASP composition and anti-tumour properties
(WILEY Online Library, 2023) Alessio, Nicola; Acar, Mustafa Burak; Squillaro, Tiziana; Aprile, Domenico; Ayaz-Güner, Şerife; Di Bernardo, Giovanni; Peluso, Gianfranco; Özcan, Servet; Galderisi, Umberto; 0000-0002-1052-0961; AGÜ, Yaşam ve Doğa Bilimleri Fakültesi, Moleküler Biyoloji ve Genetik Bölümü; Ayaz-Güner, Şerife
Genotoxic injuries converge on senescence-executive program that promotes production of a senescence-specific secretome (SASP). The study of SASP is particularly intriguing, since through it a senescence process, triggered in a few cells, can spread to many other cells and produce either beneficial or negative consequences for health. We analysed the SASP of quiescent mesenchymal stromal cells (MSCs) following stress induced premature senescence (SIPS) by ionizing radiation exposure. We performed a proteome analysis of SASP content obtained from early and late senescent cells. The bioinformatics studies evidenced that early and late SASPs, besides some common ontologies and signalling pathways, contain specific factors. In spite of these differences, we evidenced that SASPs can block in vitro proliferation of cancer cells and promote senescence/apoptosis. It is possible to imagine that SASP always contains core components that have an anti-tumour activity, the progression from early to late senescence enriches the SASP of factors that may promote SASP tumorigenic activity only by interacting and instructing cells of the immune system. Our results on Caco-2 cancer cells incubated with late SASP in presence of peripheral white blood cells strongly support this hypothesis. We evidenced that quiescent MSCs following SIPS produced SASP that, while progressively changed its composition, preserved the capacity to block cancer growth by inducing senescence and/or apoptosis only in an autonomous manner.
Proteomic and Biological Analysis of the Effects of Metformin Senomorphics on the Mesenchymal Stromal Cells
(FRONTIERS MEDIA SAAVENUE DU TRIBUNAL FEDERAL 34, LAUSANNE CH-1015, SWITZERLAND, 2021) Acar, Mustafa Burak; Ayaz-Guner, Serife; Gunaydin, Zeynep; Karakukcu, Musa; Peluso, Gianfranco; Di Bernardo, Giovanni; Ozcan, Servet; Galderisi, Umberto; 0000-0002-1052-0961; AGÜ, Yaşam ve Doğa Bilimleri Fakültesi, Moleküler Biyoloji ve Genetik Bölümü; Ayaz-Guner, Serife
Senotherapeutics are new drugs that can modulate senescence phenomena within tissues and reduce the onset of age-related pathologies. Senotherapeutics are divided into senolytics and senomorphics. The senolytics selectively kill senescent cells, while the senomorphics delay or block the onset of senescence. Metformin has been used to treat diabetes for several decades. Recently, it has been proposed that metformin may have anti-aging properties as it prevents DNA damage and inflammation. We evaluated the senomorphic effect of 6 weeks of therapeutic metformin treatment on the biology of human adipose mesenchymal stromal cells (MSCs). The study was combined with a proteome analysis of changes occurring in MSCs' intracellular and secretome protein composition in order to identify molecular pathways associated with the observed biological phenomena. The metformin reduced the replicative senescence and cell death phenomena associated with prolonged in vitro cultivation. The continuous metformin supplementation delayed and/or reduced the impairment of MSC functions as evidenced by the presence of three specific pathways in metformin-treated samples: 1) the alpha-adrenergic signaling, which contributes to regulation of MSCs physiological secretory activity, 2) the signaling pathway associated with MSCs detoxification activity, and 3) the aspartate degradation pathway for optimal energy production. The senomorphic function of metformin seemed related to its reactive oxygen species (ROS) scavenging activity. In metformin-treated samples, the CEBPA, TP53 and USF1 transcription factors appeared to be involved in the regulation of several factors (SOD1, SOD2, CAT, GLRX, GSTP1) blocking ROS.
Protocol for cell surface biotinylation of magnetic labeled and captured human peripheral blood mononuclear cells
(Cell Press, 2022) Ayaz-Guner, Serife; Acar, Mustafa Burak; Boyvat, Dudu; Guner, Huseyin; Bozalan, Habibe; Güzel, Melis; Yıldır, Selin Kübra; Altınsoy, Nilay; Fındık, Fatma; Karakükçü, Musa; Özcan, Servet; 0000-0002-1052-0961; 0000-0002-0220-5224; AGÜ, Yaşam ve Doğa Bilimleri Fakültesi, Moleküler Biyoloji ve Genetik Bölümü; Boyvat, Dudu; Ayaz-Guner, Şerife; Guner, Huseyin
Analysis of the surfaceome of a blood cell subset requires cell sorting, followed by surface protein enrichment. Here, we present a protocol combining magnetically activated cell sorting (MACS) and surface biotinylation of the target cell subset from human peripheral blood mononuclear cells (PBMCs). We describe the steps for isolating target cells and their in-column surface biotinylation, followed by isolation and mass spectrometry analysis of biotinylated proteins. The protocol enables in-column surface biotinylation of specific cell subsets with minimal membrane disruption.
A subtractive proteomics approach for the identification of immunodominant Acinetobacter baumannii vaccine candidate proteins
(FRONTIERS MEDIA SA, 2022) Acar, Mustafa Burak; Ayaz-Guner, Serife; Guner, Huseyin; Dinc, Gokcen; Kilic, Aysegul Ulu; Doganay, Mehmet; Ozcan, Servet; 0000-0002-0220-5224; 0000-0002-1052-0961; AGÜ, Yaşam ve Doğa Bilimleri Fakültesi, Moleküler Biyoloji ve Genetik Bölümü; Ayaz-Guner, Serife; Guner, Huseyin
Background: Acinetobacter baumannii is one of the most life-threatening multidrug-resistant pathogens worldwide. Currently, 50%–70% of clinical isolates of A. baumannii are extensively drug-resistant, and available antibiotic options against A. baumannii infections are limited. There is still a need to discover specific de facto bacterial antigenic proteins that could be effective vaccine candidates in human infection. With the growth of research in recent years, several candidate molecules have been identified for vaccine development. So far, no public health authorities have approved vaccines against A. baumannii. Methods: This study aimed to identify immunodominant vaccine candidate proteins that can be immunoprecipitated specifically with patients’ IgGs, relying on the hypothesis that the infected person’s IgGs can capture immunodominant bacterial proteins. Herein, the outer-membrane and secreted proteins of sensitive and drug-resistant A. baumannii were captured using IgGs obtained from patient and healthy control sera and identified by Liquid Chromatography- Tandem Mass Spectrometry (LC-MS/MS) analysis. Results: Using the subtractive proteomic approach, we determined 34 unique proteins captured only in drug-resistant A. baumannii strain via patient sera. After extensively evaluating the predicted epitope regions, solubility, transverse membrane characteristics, and structural properties, we selected several notable vaccine candidates. Conclusion: We identified vaccine candidate proteins that triggered a de facto response of the human immune system against the antibiotic-resistant A. Frontiers in Immunology 01 frontiersin.org OPEN ACCESS EDITED BY Saeed Khalili, Shahid Rajaee Teacher Training University, Iran REVIEWED BY Abbas Yadegar, Shahid Beheshti University of Medical Sciences, Iran Prince Sharma, Panjab University, India Seung Il Kim, Korea Basic Science Institute (KBSI), South Korea *CORRESPONDENCE Servet Özcan ozcan@erciyes.edu.tr SPECIALTY SECTION This article was submitted to Vaccines and Molecular Therapeutics, a section of the journal Frontiers in Immunology RECEIVED 23 July 2022 ACCEPTED 10 October 2022 PUBLISHED 10 November 2022 CITATION Acar MB, Ayaz-Güner S¸, Güner H, Dinc¸ G, Ulu Kılıc¸ A, Dog˘ anay M and Özcan S (2022) A subtractive proteomics approach for the identification of immunodominant Acinetobacter baumannii vaccine candidate proteins. Front. Immunol. 13:1001633. doi: 10.3389/fimmu.2022.1001633 COPYRIGHT © 2022 Acar, Ayaz-Güner, Güner, Dinc¸, Ulu Kılıc¸, Dog˘ anay and Özcan. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. TYPE Original Research PUBLISHED 10 November 2022 DOI 10.3389/fimmu.2022.1001633 baumannii. Precipitation of bacterial proteins via patient immunoglobulins was a novel approach to identifying the proteins that could trigger a response in the patient immune system.