3D culture and FOSL1 reduce senescence markers in corneal niche cells
Six days in Matrigel reduced senescence markers and boosted division in limbal niche cells; FOSL1 emerged as the transcription factor driving the shift, with mitochondrial function responding to its manipulation in both directions.
Six days in a three-dimensional gel changed the state of limbal niche cells: in Matrigel (a laboratory gel in which cells assemble into spheroid clusters), the share of dividing cells rose and the fraction carrying senescence markers fell, compared with conventional flat culture. The paper appeared September 8 in Aging Cell.
Limbal niche cells sit at the border between the cornea and the sclera and maintain the microenvironment for epithelial stem cells that renew the transparent corneal surface. Repeated passaging in flat culture gradually loads these cells with replicative senescence markers: they divide more slowly, which limits the pool of cellular material available for subsequent work. The same group showed in a 2012 study that transferring already expanded cells into three-dimensional Matrigel partially restored protein markers associated with a stem cell-like state. The new paper asks the question more precisely: how does a three-dimensional environment alter senescence markers specifically, and which protein is involved.
The authors compared single-cell expression profiles. Two clusters with senescence signatures shrank in the three-dimensional condition; a cluster of cells actively replicating DNA before division expanded. Cross-referencing genes whose activity declined with passaging and recovered in three-dimensional culture produced 21 candidates. Among them was FOSL1, a transcription factor (a protein that regulates the activity of other genes).
The authors then manipulated FOSL1 levels in both directions. Knocking it down in early-passage cells reduced division frequency and increased senescence markers; reactive oxygen species rose, mitochondria swelled, their cristae became disorganized, and membrane potential dropped. Overexpressing FOSL1 in late-passage cells increased division frequency and reduced senescence markers; reactive oxygen species declined, and mitochondrial structure and membrane potential recovered.
This is laboratory work on cells from human donor tissue. In this model, the culture environment set the cellular state that cells carried into the next stage of work.
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[1] pmc.ncbi.nlm.nih.gov
[2] pmc.ncbi.nlm.nih.gov
The FOSL1/limbal-cell paper is concrete mechanistic biology with a clear result and a clear limit (lab only, no patient data). The Experiment organization on Eternal Search is a funder of early-stage scientific research; the page is surfaced as a discovery entry point for readers tracking who backs this kind of fundamental cell biology. No specific Experiment-to-study link is asserted because none is established in the source material.