Biology subjects

Rosiek, E.

Publications and source records attributed to Rosiek, E..

3 recordsLinked to original sources

bioRxiv2023

ERG-driven prostate cancer emerges from basal-luminal hybrid cells

To gain insight into how ERG translocations cause prostate cancer, we performed single cell transcriptional profiling of an autochthonous mouse model at an early stage of disease initiation. Despite broad expression of ERG in all prostate epithelial cells, proliferation was enriched in a small, stem-like population with mixed-luminal basal identity (called intermediate cells). Through a series of lineage tracing and primary prostate tissue transplantation experiments, we find that tumor initiating activity resides in a subpopulation of basal cells that co-express the luminal genes Tmprss2 and Nkx3.1 (called BasalLum) but not in the larger population of classical Krt8+ luminal cells. Upon ERG activation, BasalLum cells give rise to the highly proliferative intermediate state, which subsequently transitions to the larger population of Krt8+ luminal cells characteristic of ERG-positive human cancers. Furthermore, this proliferative population is characterized by an ERG-specific chromatin state enriched for NFkB, AP-1, STAT and NFAT binding, with implications for TF cooperativity. The fact that the proliferative potential of ERG is enriched in a small stem-like population implicates the chromatin context of these cells as a critical variable for unmasking its oncogenic activity.

cancer biology↗

bioRxiv2022

Apoptotic contraction drives target cell release by cytotoxic T cells

Cytotoxic T lymphocytes (CTLs) use immune synapses to destroy infected or transformed target cells. Although the mechanisms governing synapse assembly have been studied extensively, little is known about how this interface dissociates, which is a critical step that both frees the CTL to search for additional prey and enables the phagocytosis of target corpses. Here, we applied time-lapse imaging to explore the basis for synapse dissolution and found that it occurred concomitantly with the cytoskeletal contraction of apoptotic targets. Genetic and pharmacological disruption of apoptotic contraction indicated that it was necessary for CTL dissociation. Furthermore, acute stimulation of contractile forces triggered the release of live targets, demonstrating that contraction is sufficient to drive the response. Finally, mechanically amplifying apoptotic contractility promoted faster CTL detachment and serial killing. Collectively, these results establish a biophysical basis for synapse dissolution and highlight the importance of mechanosensory feedback in the regulation of cell-cell interactions.

immunology↗

bioRxiv2019

Active modulation of Hydrogen bonding by sericin enhances cryopreservation outcomes

Cryopreservation of cells without any toxicity concerns is a critical step in ensuring successful clinical translation of cell-based technologies. Mitigating the toxicity concerns related to most of the commonly used cryoprotectants including dimethyl sulfoxide (DMSO) is an active area of research in cryobiology. In recent years use of additives including polymeric proteins such has sericin have been explored as an additive to cryoprotectant formulations. In this study the thermophysical effect of addition of sericin was investigated. The effect of presence of sericin on the H-bonding strength was investigated using Raman microspectroscopy and other thermophysical effects were quantified using differential scanning calorimetry (DSC) techniques. Finally, the prospect of using sericin as an additive to cryoprotectant formulation was investigated by monitoring cellular viability and growth following exposure to cryogenic temperatures in hepatocellular carcinoma cells. Results indicate significant improvement in post-thaw viability when sericin is used as an additive to DMSO based formulations. While use of trehalose as an additive has beneficial effects by itself, combined usage of sericin and trehalose as additives did result in an improved overall long-term growth potential of the cells.\n\nStatement of SignificanceThis study provides for powerful biophysical understanding of how sericin can be used as an additive for cryoprotectant solutions, which allows storage of biologics at low temperatures. It is desirable to replace current components of cryoprotectant formulation (such as DMSO) due to innate toxicity and metabolic derangements to cells. The ability of sericin to improve cryoprotective solutions was mechanistically characterized by Raman microspectroscopy, which allows for molecular level characterization of the nature of H-bonding in aqueous environments in presence of solution components. Thermodynamic analysis of the cryoprotectant solutions containing sericin was undertaken to quantify the relation between solution composition and cryopreservation outcome. This analytical study provides a basis for designing better cryoprotectants with lower thermophysical injury and higher cellular yields.

bioengineering↗