Dimensionality and confinement reshape competition in cellular renewing active matter

TL;DR

This study explores how dimensionality and spatial confinement influence competition mechanisms in cellular renewing active matter, revealing complex interactions affecting tissue structure and growth dynamics.

Contribution

It extends previous one-dimensional models to two dimensions and introduces boundary effects, demonstrating how these factors alter competition and tissue organization.

Findings

Opportunistic and homeostatic-pressure competition jointly influence clonal selection in 2D.

Boundaries weaken homeostatic pressure competition and induce spatial heterogeneity.

Confinement promotes tangential cell alignment and alters competitive outcomes at tissue edges.

Abstract

Cellular renewing active matter - assemblies of proliferating and apoptotic cells - underlies tissue homeostasis, morphogenesis, and clonal competition. Previous work in one-dimensional periodic systems identified a fitness advantage associated with rapid dead-cell clearance, an "opportunistic" competition mechanism. Extending this framework, we study two-dimensional cellular aggregates and show that dimensionality modifies the interplay between competition mechanisms for clones with different clearance rates: in 2D, opportunistic and homeostatic-pressure-based competition jointly shape clonal selection, to varying degrees. We then introduce an explicit circular confinement to probe how boundaries modulate this interplay. While opportunistic competition persists, distinct timescale-dependent behaviors emerge through weakened homeostatic-pressure-based competition near boundaries. Structural analysis reveals that confinement promotes tangential alignment and spatially heterogeneous homeostatic pressure, thereby reshaping competitive outcomes at tissue edges. Our study connects newly discovered competition mechanisms with more realistic biological contexts, highlighting how dimensionality and spatial constraints influence tissue structures and modulate competition in heterogeneous cell populations, with implications for tumor growth dynamics and tissue development.