Biology subjects

Karageorgiou, C.

Publications and source records attributed to Karageorgiou, C..

3 recordsLinked to original sources

bioRxiv2024

Transcriptomics effects of per- and polyfluorinated alkyl substances in differentiated neuronal cells

Per- and polyfluorinated alkyl substances (PFAS) are pervasive environmental contaminants that bioaccumulate in tissues and pose risks to human health. Increasing evidence links PFAS to neurodegenerative and behavioral disorders, yet the underlying mechanisms of their effects on neuronal function remain largely unexplored. In this study, we utilized SH-SY5Y neuroblastoma cells, differentiated into neuronal-like cells, to investigate the impact of six PFAS compounds-- perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorodecanoic acid (PFDA), perfluorodecanesulfonic acid (PFDS), 8:2 fluorotelomer sulfonate (8:2 FTS), and 8:2 fluorotelomer alcohol (8:2 FTOH)--on neuronal health. Following a 30 M exposure for 24 hours, PFAS accumulation ranged from 100-7500 ng/mg of protein. Transcriptomic analysis revealed 721 differentially expressed genes (DEGs) across treatments (padj < 0.05), with 11 DEGs shared among all PFAS exposures, indicating potential biomarkers for neuronal PFAS toxicity. PFOA-treated cells showed downregulation of genes involved in synaptic growth and neural function, while PFOS, PFDS, 8:2 FTS, and 8:2 FTOH exposures resulted in upregulation of genes related to hypoxia response and amino acid metabolism. Lipidomic profiling further demonstrated significant fatty acid upregulation with PFDA, PFDS, and 8:2 FTS, alongside triacylglycerol downregulation with 8:2 FTOH. These findings suggest that the neurotoxic effects of PFAS are structurally dependent, offering insights into the molecular processes that may drive PFAS-induced neuronal dysfunction. SynopsisPer- and poly fluorinated alkyl substances (PFAS) have been shown to bioaccumulate in human tissues and affect health. This study aims to provide insights into the specific biological processes through which PFAS exposure affects neuronal cells.

pharmacology and toxicology↗

bioRxiv2023

Ancient AMY1 gene duplications primed the amylase locus for adaptive evolution upon the onset of agriculture

Starch digestion is a cornerstone of human nutrition. The amylase genes code for the starch-digesting amylase enzyme. Previous studies suggested that the salivary amylase (AMY1) gene copy number increased in response to agricultural diets. However, the lack of nucleotide resolution of the amylase locus hindered detailed evolutionary analyses. Here, we have resolved this locus at nucleotide resolution in 98 present-day humans and identified 30 distinct haplotypes, revealing that the coding sequences of all amylase gene copies are evolving under negative selection. The phylogenetic reconstruction suggested that haplotypes with three AMY1 gene copies, prevalent across all continents and constituting about 70% of observed haplotypes, originated before the out-of-Africa migrations of ancestral modern humans. Using thousands of unique 25 base pair sequences across the amylase locus, we showed that additional AMY1 gene copies existed in the genomes of four archaic hominin genomes, indicating that the initial duplication of this locus may have occurred as far back 800,000 years ago. We similarly analyzed 73 ancient human genomes dating from 300 - 45,000 years ago and found that the AMY1 copy number variation observed today existed long before the advent of agriculture ([~]10,000 years ago), predisposing this locus to adaptive increase in the frequency of higher amylase copy number with the spread of agriculture. Mechanistically, the common three-copy haplotypes seeded non-allelic homologous recombination events that appear to be occurring at one of the fastest rates seen for tandem repeats in the human genome. Our study provides a comprehensive population-level understanding of the genomic structure of the amylase locus, identifying the mechanisms and evolutionary history underlying its duplication and copy number variability in relation to the onset of agriculture.

evolutionary biology↗

bioRxiv2022

Genomic Analysis of Two Phlebotomine Sand Fly Vectors of Leishmania from the New and Old World

Phlebotomine sand flies are of global significance as important vectors of human disease, transmitting bacterial, viral, and protozoan pathogens, including the devastating kinetoplastid parasites of the genus Leishmania, the causative agents of diseases collectively termed leishmaniasis. More than 40 pathogenic Leishmania species are transmitted to humans by approximately 35 sand fly species in 98 countries with hundreds of millions of people at risk around the world. As no approved efficacious vaccine exists, available drugs are expensive and/or toxic, and resistance is emerging, management of sand fly populations to break transmission is currently the most effective disease control strategy. To better understand the biology of sand flies, including the mechanisms involved in their vectorial capacity, insecticide resistance, and population structures we sequenced the genomes of two of the most important sand fly species: Phlebotomus papatasi, a cutaneous leishmaniasis vector, (distributed in the Middle East and North Africa) and Lutzomyia longipalpis, a visceral leishmaniasis vector (distributed across Central and South America). We categorized and curated genes involved in processes important to their roles as disease vectors, including chemosensation, blood feeding, circadian rhythm, immunity, and detoxification, as well as mobile genetic elements. We also defined gene orthology and observed micro-synteny among the genomes. Finally, we present the genetic diversity and population structure of these species in their respective geographical areas. These genomes will be a foundation on which to base future efforts to prevent vector-borne transmission of Leishmania parasites. Author SummaryThe leishmaniases are a group of neglected tropical diseases caused by protist parasites from the Genus Leishmania. Different Leishmania species present a wide clinical profile, ranging from mild, often self-resolving cutaneous lesions that can lead to protective immunity, to severe metastatic mucosal disease, to visceral disease that is ultimately fatal. Leishmania parasites are transmitted by the bites of sand flies, and as no approved vaccine exists, available drugs are toxic and/or expensive and resistance is emerging, new dual control strategies to combat these diseases must be developed, combining interventions on human infections and integrated sand fly population management. Effective vector control requires a good understanding of the biology of sand flies. To this end, we sequenced and annotated the genomes of two sand fly species that are important leishmaniasis vectors from the Old and New Worlds. These genomes allow us to better understand, at the genetic level, processes important in the vector biology of these species, such as finding hosts, blood-feeding, immunity, and detoxification. These genomic resources highlight the driving forces of evolution of two major Leishmania vectors and provide foundations for future research on how to better prevent leishmaniasis by control of the sand fly vectors.

genomics↗