Sotiris Ouzounis

Mr. Sotiris Ouzounis

National Hellenic Research Foundation, Athens, Attikí, Greece
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orcid

Research Focus & Metrics

Academic Career Length

6Years (2021-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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17 November 2021 in Microorganisms
Verified
Journal Article
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PPPanayiotis Papadakis
Panayiotis Papadakis
SKSpyros J Konteles
Spyros J Konteles
ABAnthimia Batrinou
Anthimia Batrinou
SOSotiris Ouzounis
Sotiris Ouzounis
TTTheofania Tsironi
Theofania Tsironi
DHDIMITRA HOUHOULA
DIMITRA HOUHOULA
Background: The identification of bacterial species in fermented PDO (protected designation of origin) cheese is important since they contribute significantly to the final organoleptic properties, the ripening process, the shelf life, the safety and the overall quality of cheese. Methods: Ten commercial PDO feta cheeses from two geographic regions of Greece, Epirus and Thessaly, were analyzed by 16S metagenomic analysis. Results: The biodiversity of all the tested feta cheese samples consisted of five phyla, 17 families, 38 genera and 59 bacterial species. The dominant phylum identified was Firmicutes (49% of the species), followed by Proteobacteria (39% of the species), Bacteroidetes (7% of the species), Actinobacteria (4% of the species) and Tenericutes (1% of the species). Streptococcaceae and Lactobacillaceae were the most abundant families, in which starter cultures of lactic acid bacteria (LAB) belonged, but also 21 nonstarter lactic acid bacteria (NSLAB) were identified. Both geographical areas showed a distinctive microbiota fingerprint, which was ultimately overlapped by the application of starter cultures. In the rare biosphere of the feta cheese, Zobellella taiwanensis and Vibrio diazotrophicus, two Gram-negative bacteria which were not previously reported in dairy samples, were identified. Conclusions: The application of high-throughput DNA sequencing may provide a detailed microbial profile of commercial feta cheese produced with pasteurized milk.

1 July 2023 in OMICS: A Journal of Integrative Biology
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Journal Article
Open access
SOSotiris Ouzounis
Sotiris Ouzounis
VPVasilis Panagiotopoulos
Vasilis Panagiotopoulos
VBVivi Bafiti
Vivi Bafiti
Panagiotis ZoumpoulakisPanagiotis Zoumpoulakis
Panagiotis Zoumpoulakis
DCDionisis Cavouras
Dionisis Cavouras
Theodora KatsilaTheodora Katsila
Theodora Katsila
Human cytochrome P450 (CYP450) enzymes play a crucial role in drug metabolism and pharmacokinetics. CYP450 inhibition can lead to toxicity, in particular when drugs are co-administered with other drugs and xenobiotics or in the case of polypharmacy. Predicting CYP450 inhibition is also important for rational drug discovery and development, and precision in drug repurposing. In this overarching context, digital transformation of drug discovery and development, for example, using machine and deep learning approaches, offers prospects for prediction of CYP450 inhibition through computational models. We report here the development of a majority-voting machine learning framework to classify inhibitors and noninhibitors for seven major human liver CYP450 isoforms (CYP1A2, CYP2A6, CYP2B6, CYP2C9, CYP2C19, CYP2D6, and CYP3A4). For the machine learning models reported herein, we employed interaction fingerprints that were derived from molecular docking simulations, thus adding an additional layer of information for protein-ligand interactions. The proposed machine learning framework is based on the structure of the binding site of isoforms to produce predictions beyond previously reported approaches. Also, we carried out a comparative analysis so as to identify which representation of test compounds (molecular descriptors, molecular fingerprints, or protein-ligand interaction fingerprints) affects the predictive performance of the models. This work underlines the ways in which the structure of the enzyme catalytic site influences machine learning predictions and the need for robust frameworks toward better-informed predictions.

1 July 2023 in Aquaculture and Fisheries
Verified
Journal Article
Open access
ATApollon Thomas
Apollon Thomas
SKSpyros J. Konteles
Spyros J. Konteles
SOSotiris Ouzounis
Sotiris Ouzounis
SPSpyros Papatheodorou
Spyros Papatheodorou
ATAliki Tsakni
Aliki Tsakni
TTTheofania Tsironi
Theofania Tsironi

16 June 2022 in Current Oncology
Verified
Journal Article
Open access
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VBVivi Bafiti
Vivi Bafiti
SOSotiris Ouzounis
Sotiris Ouzounis
CCConstantina Chalikiopoulou
Constantina Chalikiopoulou
EGEftychia Grigorakou
Eftychia Grigorakou
IGIoanna Maria Grypari
Ioanna Maria Grypari
Theodora KatsilaTheodora Katsila
Theodora Katsila
Malignant gliomas constitute a complex disease phenotype that demands optimum decision-making as they are highly heterogeneous. Such inter-individual variability also renders optimum patient stratification extremely difficult. microRNA (hsa-miR-20a, hsa-miR-21, hsa-miR-21) expression levels were determined by RT-qPCR, upon FFPE tissue sample collection of glioblastoma multiforme patients (n = 37). In silico validation was then performed through discriminant analysis. Immunohistochemistry images from biopsy material were utilized by a hybrid deep learning system to further cross validate the distinctive capability of patient risk groups. Our standard-of-care treated patient cohort demonstrates no age- or sex- dependence. The expression values of the 3-miRNA signature between the low- (OS > 12 months) and high-risk (OS < 12 months) groups yield a p-value of 12 months) vs. high-risk (OS < 12 months) glioblastoma multiforme patients. Our 3-microRNA signature (hsa-miR-20a, hsa-miR-21, hsa-miR-10a) may further empower glioblastoma multiforme prognostic evaluation in clinical practice and enrich drug repurposing pipelines.

28 February 2023 in Metabolites
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Journal Article
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VBVivi Bafiti
Vivi Bafiti
SOSotiris Ouzounis
Sotiris Ouzounis
ESEleni Siapi
Eleni Siapi
IGIoanna Maria Grypari
Ioanna Maria Grypari
ATAndreas Theofanopoulos
Andreas Theofanopoulos
Theodora KatsilaTheodora Katsila
Theodora Katsila
The accumulation of cell biomass is associated with dramatically increased bioenergetic and biosynthetic demand. Metabolic reprogramming, once thought as an epiphenomenon, currently relates to disease progression, also in response to extracellular fate-decisive signals. Glioblastoma multiforme patients often suffer misdiagnosis, short survival time, low quality of life, and poor disease management options. Today, tumor genetic testing and histological analysis guide diagnosis and treatment. We and others appreciate that metabolites complement translational biomarkers and molecular signatures in disease profiling and phenotyping. Herein, we coupled a mixed-methods content analysis to a mass spectrometry-based untargeted metabolomic analysis on plasma samples from glioblastoma multiforme patients to delineate the role of metabolic remodeling in biological plasticity and, hence, disease severity. Following data processing and analysis, we established a bioenergetic profile coordinated by the mitochondrial function and redox state, lipids, and energy substrates. Our findings show that epigenetic modulators are key players in glioblastoma multiforme cell metabolism, in particular when microRNAs are considered. We propose that biological plasticity in glioblastoma multiforme is a mechanism of adaptation and resistance to treatment which is eloquently revealed by bioenergetics.

14 October 2022 in Cancers
Verified
Journal Article
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PKParaskevi Kogionou
Paraskevi Kogionou
SFSotirios P. Fortis
Sotirios P. Fortis
MGMaria Goulielmaki
Maria Goulielmaki
NANicolas Aubert
Nicolas Aubert
PBPanagiota Batsaki
Panagiota Batsaki
Constantin N. BaxevanisConstantin N. Baxevanis
Constantin N. Baxevanis
Radiotherapy for localized prostate cancer has increased the cure and survival rates of patients. Besides its local tumoricidal effects, ionizing radiation has been linked to mechanisms leading to systemic immune activation, a phenomenon called the abscopal effect. In this study, we performed gene expression analysis on peripheral blood from prostate cancer patients obtained post- radiotherapy and showed that 6 genes, including CCR7, FCGR2B, BTLA, CD6, CD3D, and CD3E, were down-regulated by a range of 1.5–2.5-fold as compared to pre-radiotherapy samples. The expression of the signature consisting of these six genes was also significantly lower post- vs. pre-radiotherapy. These genes are involved in various tumor-promoting immune pathways and their down-regulation post-radiotherapy could be considered beneficial for patients. This is supported by the fact that low mRNA expression levels for the 6-gene signature in the prostate tumor tissue was linked to better survival. Importantly, we report that this 6-gene signature strongly correlated with a favorable prognosis regardless of poor standard clinicopathological parameters (i.e., Gleason score ≥ 8 and T3 (including T3a and T3b). Our pioneering data open the possibility that the 6-gene signature identified herein may have a predictive value, but this requires further long-term studies.