Biology subjects

Salmon-Divon, M.

Publications and source records attributed to Salmon-Divon, M..

5 recordsLinked to original sources

bioRxiv2025

Sex-Based Transcriptomic Differences in Psoriatic Lesions: A Comprehensive Meta-Analysis

Psoriasis, a chronic inflammatory skin disease affecting men and women equally, presents distinct gender-based differences in severity and treatment response. While molecular mechanisms underlying psoriasis are well-studied, sex-specific differences remain largely unexplored. To address this, we conducted a meta-analysis of transcriptomic data from lesional psoriasis skin and healthy controls, comparing male and female cohorts.Our findings reveal 2,760 overlapping differentially expressed genes (DEGs) between sexes, highlighting shared pathways like IL-17 signaling and Th17 differentiation. However, sex-specific pathways emerged, including male-enriched PI3K-Akt signaling and chemokine receptor activity, and female-enriched glycolysis and AHR-NRF2 pathways. Upstream regulator analysis identified sex-specific drivers, including VEGFA activation and CFTR inhibition in males, and AHR activation and FGF21 inhibition in females. Notably, Tregs and neutrophil abundance differed by sex, aligning with disease severity trends. These results highlight critical molecular and cellular disparities, emphasizing the need for personalized, sex-specific therapeutic approaches in psoriasis management. TeaserGender disparities in psoriatic lesions reveal transcriptomic differences and variations in neutrophil cell type abundance.

bioinformatics↗

bioRxiv2023

CTCF supports melanoma cell migration by repressing cholesterol biosynthesis

CTCF is a key factor in three-dimensional chromatin folding and transcriptional control that was found to affect cancer cell migration by a mechanism that is still poorly understood. To identify this mechanism, we used mouse melanoma cells with a partial loss of function (pLoF) of CTCF. We found that CTCF pLoF inhibits cell migration rate while leading to an increase in the expression of multiple enzymes in the cholesterol biosynthesis pathway along with an elevation in the cellular cholesterol levels. Inhibition of cholesterol synthesis in CTCF pLoF cells restored the cellular migration rate, suggesting that CTCF supports cell migration by suppressing cholesterol synthesis. Detailed analysis of the promoter of Hmgcs1, an early enzyme in the cholesterol synthesis pathway, revealed that CTCF enables PRC2 recruitment to the promoter and deposition of H3K27me3 to prevent SREBP2 binding and activation of transcription. By this mechanism CTCF fine-tunes cholesterol levels to support cell migration. Notably, genome wide association studies suggest a link between CTCF and cholesterol-associated diseases, thus CTCF emerges as a new regulator of cholesterol biosynthesis.

genomics↗

bioRxiv2021

High-resolution screening for marine prokaryotic and eukaryotic taxa with selective preference for PE and PET surfaces

Marine plastic debris serve as substrates for the colonization of a variety of prokaryote and eukaryote organisms. Of particular interest are the microorganisms that have adapted to thrive on plastic as they may contain genes, enzymes or pathways involved in the colonization or metabolism of plastics. We implemented DNA metabarcoding with nanopore MinION sequencing to compare the one-month-old biomes of hydrolysable (polyethylene terephthalate) and non-hydrolysable (polyethylene) plastics surfaces vs. those of glass and the surrounding water in a Mediterranean Sea marina. We sequenced longer 16S rRNA, 18S rRNA and ITS barcode loci for a more comprehensive taxonomic profiling of the bacterial, protist and fungal communities respectively. Long read sequencing enabled high-resolution mapping to genera and species. Using differential abundance screening we identified 32 bacteria and five eukaryotic species, that were differentially abundant on plastic compared to glass. This approach may be used in the future to characterize the plastisphere communities and to screen for microorganisms with a plastic-metabolism potential.

microbiology↗

bioRxiv2021

Homologous recombination repair creates mutations in the non-coding genome that alter Topoisomerase-1 cleavage sites & orchestrates irinotecan resistance

Resistance to chemotherapy is a leading cause of treatment failure. Drug-resistance mechanisms involve mutations in specific proteins or changes in their expression levels. It is commonly understood that resistance mutations happen randomly prior to treatment and are selected during the treatment. However, selection of drug-resistant mutants in culture could be achieved by multiple drug exposures of cloned genetically identical cells, and thus cannot result from selection of pre-existent mutations. Accordingly, adaptation must involve generation of mutations de-novo upon drug treatment. Here we explored the origin of resistance mutations to a widely used Top1 inhibitor irinotecan, which triggers DNA breaks, causing cytotoxicity. Resistance mechanism involved gradual accumulation of recurrent mutations in non-coding regions of DNA at Top1-cleavage sites. Surprisingly, cancer cells had higher number of such sites than reference genome, which may define their increased sensitivity to irinotecan. Homologous recombination repair of DNA double strand breaks at these sites following initial drug exposures gradually reverted cleavage-sensitive "cancer" sequences back to cleavage-resistant "normal" sequences. These mutations reduced generation of DNA breaks upon subsequent exposures, thus gradually increasing the drug resistance. Together, large target size for mutations and their Top1-guided generation lead to their gradual and rapid accumulation, synergistically accelerating development of resistance. Abstract Figure O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=78 SRC="FIGDIR/small/470089v3_ufig1.gif" ALT="Figure 1"> View larger version (24K): org.highwire.dtl.DTLVardef@d9d93forg.highwire.dtl.DTLVardef@45b88forg.highwire.dtl.DTLVardef@157cafeorg.highwire.dtl.DTLVardef@cff4a4_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2018

The heterochromatin landscape in migrating cells and the importance of H3K27me3 for migration-associated transcriptional changes

H3K9me3, H3K27me3 and H4K20me1 are epigenetic markers associated with chromatin condensation and transcriptional repression. Previously, we found that migration of melanoma cells is associated with and dependent on global chromatin condensation that includes a global increase in these markers. Taken together with more recent reports by others suggest it is a general signature of migrating cells. Here, to learn about the function of these markers in migrating cells we mapped them by ChIP-seq analysis. This analysis revealed that induction of migration leads to expansion of these markers along the genome and to an increased overlapping between them. Significantly, induction of migration led to a higher increase in H3K9me3 and H4K20me1 signals at repetitive elements than at protein-coding genes, while an opposite pattern was found for H3K27me3. Transcriptome analysis revealed that 182 altered genes following induction of migration, of which 33% are dependent on H3K27me3 for these changes. H3K27me3 was also required to prevent changes in the expression of 501 other genes upon induction of migration. Taken together our results suggest that heterochromatinization in migrating cells is global and not restricted to specific genomic loci and that H3K27me3 is a key component in executing a migration-specific transcriptional plan.

cell biology↗