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Giannakakis, A.

Publications and source records attributed to Giannakakis, A..

2 recordsLinked to original sources

APNet, an explainable sparse deep learning model to discover differentially active drivers of severe COVID-19

MotivationComputational analyses of plasma proteomics provide translational insights into complex diseases such as COVID-19 by revealing molecules, cellular phenotypes, and signaling patterns that contribute to unfavorable clinical outcomes. Current in silico approaches dovetail differential expression, biostatistics, and machine learning, but often overlook nonlinear proteomic dynamics, like post-translational modifications, and provide limited biological interpretability beyond feature ranking. ResultsWe introduce APNet, a novel computational pipeline that combines differential activity analysis based on SJARACNe co-expression networks with PASNet, a biologically-informed sparse deep learning model to perform explainable predictions for COVID-19 severity. The APNet driver-pathway network ingests co-expression and classification weights to aid result interpretation and hypothesis generation. APNet outperforms alternative models in patient classification across three COVID-19 proteomic datasets, identifying predictive drivers and pathways, including some confirmed in single-cell omics and highlighting under-explored biomarker circuitries in COVID-19. Availability and ImplementationAPNets R, Python scripts and Cytoscape methodologies are available at https://github.com/BiodataAnalysisGroup/APNet Contactggeorav@certh.gr Supplementary informationSupplementary information can be accessed in Zenodo (10.5281/zenodo.10438830).

systems biology↗

Aggregatibacter actinomycetemcomitans LtxA hijacks endocytic trafficking pathways in human lymphocytes

Leukotoxin (LtxA) from oral pathogen Aggregatibacter actinomycetemcomitans is a secreted membrane-damaging protein. LtxA is internalized by {beta}2 integrin LFA-1 (CD11a/CD18) expressing leukocytes and ultimately causes cell death; however toxin localization in the host cell is poorly understood and these studies fill this void. We investigated LtxA trafficking using multi-fluor confocal imaging, flow cytometry and Rab5 knockdown in human T lymphocyte Jurkat cells. Planar lipid bilayers were used to characterize LtxA pore-forming activity at different pH. Our results demonstrate that LtxA/LFA-1 complex gains an access to the cytosol of Jurkat cells without evidence of plasma membrane damage utilizing dynamin-dependent and clathrin-independent mechanism. Upon internalization LtxA follows the LFA-1 endocytic trafficking pathways as identified by co-localization experiments with endosomal and lysosomal markers (Rab5, Rab11A, Rab7, and Lamp2) and CD11a. Knockdown of Rab5a resulted in loss of susceptibility of Jurkat cells to LtxA cytotoxicity suggesting that late events of LtxA endocytic trafficking are required for toxicity. The toxin trafficking via the degradation endocytic pathway may culminate in delivery of the protein to lysosomes or its accumulation in Rab11A-dependent recycling endosomes. The ability of LtxA to form pores at acidic pH may result in permeabilization of the endosomal and lysosomal membranes.

microbiology↗