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Eisenklam, L.

Publications and source records attributed to Eisenklam, L..

2 recordsLinked to original sources

Abnormal nuclear organization impairs adipogenic lineage commitment and terminal maturation in Hutchinson-Gilford progeria syndrome (HGPS)

Hutchinson-Gilford progeria syndrome (HGPS) is a fatal premature aging disorder driven by progerin, a truncated Lamin A protein that destabilizes nuclear architecture and disproportionately affects mesenchymal-lineage tissues. One notable mesenchymal lineage defect in Progeria patients is early and severe subcutaneous lipodystrophy. We hypothesized that disorganized chromatin architecture underlies the failure of mesenchymal stem cell (MSC) lineage commitment and adipogenesis in HGPS. To test this while preserving donor age, epigenetic history, and tissue context, we induced adipogenesis in age-matched healthy and HGPS patient-derived dermal fibroblasts and profiled cells using imaging, bulk RNA-seq, and Hi-C across the differentiation time course. We found that HGPS fibroblasts commit to the adipogenic lineage at rates comparable to healthy controls but diverge downstream: induced cells display aberrant lipid-droplet morphology, mount a disorganized and delayed transcriptional response, and retain priming for alternative mesenchymal lineages (osteochondrogenic, vascular) alongside stalled adipogenic maturation. Hi-C revealed that HGPS fibroblasts exhibit some baseline spatial compartment differences from healthy cells, but more notably show differences in how they reorganize compartments during adipogenic induction. Compartment-transcription coupling was strong during adipogenesis for lipid-metabolic genes in healthy cells but was more dysregulated in HGPS. These results indicate that HGPS disrupts lineage consolidation rather than initiation, associated with disease-specific failures in chromatin reorganization during differentiation.

cell biology↗

H3K27me3 Drives Constricted Migration Induced 3D Genome Rewiring in Melanoma

Repeated exposure of neoplastic cells to mechanical stresses during metastasis can drive stable morphological and physiological changes. We previously showed that A375 human melanoma cells subjected to 10 rounds of constricted migration ("Bottom-10 cells") became significantly more migratory and exhibited H3K9me3 relocalization, transcriptional remodeling, and chromatin compartment changes relative to naive parental A375 cells. Because these phenotypes persist across cell divisions, we hypothesized they are driven and maintained by specific epigenetic mechanisms. Here, we profiled candidate histone modifications by CUT&RUN and applied a computational model to identify marks that explain compartment switches. In parental cells, H3K9me3 and H3K4me1 strongly predict locus stability in the B and A compartments, respectively. In contrast, changes in H3K27me3 dynamically predict A-to-B compartment switching after constricted migration. Consistently, altered H3K27me3 enrichment correlates with both differentially regulated genes and chromatin compartment changes between Bottom-10 and parental populations. We therefore tested whether inhibiting H3K27me3 deposition alters migratory potential and/or the "memory" of the increased migratory phenotype. Inhibiting EZH1/2 reduced migration efficiency overall, with a stronger effect on constricted than unconstricted migration. This reduction was accompanied by decreased genomic H3K27me3 enrichment and reversal of some compartment changes in Bottom-10 cells. However, acute treatment did not durably reverse the highly migratory Bottom-10 phenotype; cells returned to their initial state after drug removal. Chronic inhibition across many sequential rounds of constricted migration dramatically reduced the fraction of cells able to migrate. Notably, cells that migrated despite chronic EZH inhibition appeared to escape treatment, acquiring many typical Bottom-10 H3K27me3 and compartment changes even though acute inhibition tends to prevent them. Overall, these results highlight H3K27me3 as a key contributor to establishing and maintaining constricted migration-induced 3D genome changes.

genomics↗