Biology subjects

Stroka, K.

Publications and source records attributed to Stroka, K..

5 recordsLinked to original sources

bioRxiv2026

Acute priming using elevated fluid viscosity recovers young-like single-cellsurveillance behaviors in aged human T cells

Aging is a complex biological process, often characterized by increased vulnerability to disease, infection, and death. This increased vulnerability is mechanistically linked to a progressive and functional decline of the immune system. In humans, aged lymphocytes lose their capacity to effectively surveil within diverse microenvironments, decreasing their capability for clearing infections and maintaining physiological homeostasis. However, specific mechanisms by which aged lymphocytes, specifically T cells, lose this capacity to surveil remain unclear. We profiled three core characteristics of T cell surveillance at single-cell resolution, specifically migration, deformability, and sensing. While aged T cells retained their capacity for spontaneous migration, they exhibited impaired cellular deformability and deficiencies in sensing local signaling cues. To modulate this surveillance defect, we performed mechanical reprogramming using elevated fluid viscosity. Results showed that acute priming of aged T cells with elevated fluid viscosity recovered a transient young-like surveillance phenotype, which was mechanistically linked to membrane tension, cortical F-actin, and Arp3 expression. These findings reveal a key source of surveillance defects in aged T cells and provide an effective mechanical approach to tuning their single-cell behaviors. TeaserRecovery of young-like surveillance phenotypes in aging human T cells via viscosity priming

bioengineering↗

bioRxiv2026

Selective estradiol sensitivity in 12Z human endometriotic epithelial cell line

Estradiol (E2) is a potent estrogen molecule that plays a crucial role in regulating numerous healthy and pathophysiological processes. To model estrogen-dependent cellular activities in vitro in a physiologically meaningful way, cells chosen for experimentation should exhibit sensitivity to E2. The 12Z human endometriotic epithelial cell line is gaining attention as a model for estrogen-dependent conditions, but its functional responsiveness to E2 has not been well characterized. In the following study, we found that E2 does not influence 12Z proliferation, collective migration, or single-cell migration. However, 12Zs were selectively responsive to E2 in 3D migration models where the cells were physically confined. Upregulating ER, the primary mediator of estrogenic action, in the 12Zs did not enhance their functional E2 sensitivity. To delineate the underpinning of these behaviors, RNA sequencing was performed and revealed a differential expression of pseudogenes and non-coding RNAs in E2-treated 12Zs compared to vehicle control-treated 12Zs. Several signal transduction genes were significantly downregulated in ESR1-overexpressing 12Zs compared to normal 12Zs, which may play a role in their persistent lack of E2 sensitivity. These results prompt us to question whether the 12Z cell line, which mostly lacks functional E2 responsiveness, should be used in vitro as a model of estrogen-dependent processes and conditions.

cell biology↗

bioRxiv2026

Fibrotic substrate stiffness enhances endometriotic epithelial cell motility

Fibrosis is a common pathological feature of inflammatory conditions across various organ systems, leading to a marked increase in matrix stiffness. Although substrate stiffness is known to increase cell migration in cancer and stromal cell populations, it is not well understood how it affects benign epithelial cell motility, particularly within the pelvic cavity. We used an endometriotic epithelial cell line and polyacrylamide hydrogels with tunable stiffness--with glass as an extreme stiffness reference--to model mechanically driven single-cell and multicellular migration. We found that stiff substrates promoted cell speed, actin stress fiber formation, focal adhesion presentation, and spheroid expansion compared to the soft substrate. Increasing cellular contractility on the soft substrate and decreasing contractility on the stiff substrate led to an increase and decrease in cell speed, respectively. These findings provide mechanistic insight on how fibrosis as a biomechanical state regulates epithelial cell migration, with additional relevance to the pathogenesis of benign yet invasive conditions.

cell biology↗

bioRxiv2025

Perfusion Bioreactor Culture Incorporating Mechanical Confinement Enhances Mesenchymal Stem Cell Extracellular Vesicle Production and Wound Healing Potential

Mesenchymal stem cell extracellular vesicles (MSC EVs) have been widely studied for regenerative medicine and tissue repair applications. However, clinical translation of EV therapeutics has been hampered by low potency and lack of scalable production strategies. This work aims to develop a novel approach that exploits the mechanosensitivity of MSCs to enhance EV potency in the context of enhanced production via bioreactor culture. MSCs are well known to respond to mechanical stimuli such as substrate stiffness and shear stress, and here it is shown that exposing MSCs to another mechanoregulatory parameter, confinement, enhances the pro-angiogenic bioactivity of their EVs. This is consistent across both donor-derived primary MSCs and induced pluripotent stem cell-derived MSCs (iMSCs). The development of a 3D-printed perfusion bioreactor system that enables culture of confined MSCs under flow is also detailed here, resulting in a 67-fold increase in EV production compared to flask culture. iMSC EVs obtained downstream of this confinement-bioreactor culture induce greater vascularization and generally improve wound healing in a diabetic mouse model compared to iMSC EVs from conventional tissue culture. Overall, this work establishes the development of a scalable, bioreactor-based iMSC EV production platform that provides a solution to major translational bottlenecks of therapeutic EVs.

bioengineering↗

bioRxiv2025

Estradiol alters actin and protrusion dynamics in endometriotic epithelial cells

Estradiol (E2), a sex steroid hormone molecule, plays a key role in regulating the actin and shape dynamics of cells in a multitude of normal and pathophysiological conditions. While cytoskeletal rearrangements, membrane dynamics, and cellular protrusions are intimately involved in cell motility and invasiveness, little is known about the impact of E2 on these processes in estrogen-dependent epithelial cells. In this study, we quantified the impact of E2 on cell shape and actin dynamics in 12Z human endometriotic epithelial cells transfected with LifeAct-GFP and observed with lattice lightsheet microscopy, a new imaging technique fast enough to capture 3D dynamics on second timescales. E2, when applied for 24 hours, significantly decreased cell circularity, solidity, and rate of change of circularity, indicating a transition to a more elongated and less variable morphology. 24-hour E2 treatment also induced the formation of large membrane protrusions reminiscent of invadopodia and led to a more disordered flow of actin within those protrusions. However, these effects were not seen after 15 minutes of E2 treatment, suggesting that longer-term signaling is required to drive these structural changes. Together, these results suggest that E2 modulates actin polymerization and membrane protrusion dynamics in endometriotic epithelial cells and may prime them for cell invasion. This work highlights a role for hormonal signaling in mediating cytoskeletal plasticity and migratory cell phenotypes.

biophysics↗