UC Irvine

Due to the mechanosensitive nature of stem cells, intense research has also focused on the role of the cell microenvironment in directing cell fate decisions and stemness acquisition. It has been demonstrated that modulation of biophysical cues such as lateral confinement or substrate stiffness can enhance induced pluripotent stem cell (iPSC) and cancer stem cell (CSC) generation. While biophysical studies commonly involve modulating cell-cell and/or cell-ECM adhesions, a systematic study on the effect of perturbing cell adhesion during reprogramming has not been performed. Therefore, we propose to study the effect of a collection of cell-cell and cell-ECM associated genes, known as the Adhesome, on stemness acquisition of reprogramming cells, in the context of iPSC and CSC reprogramming.

Here, we report on a custom RNAi screen targeting 103 adhesome genes which demonstrated that adhesome expression is largely refractory to somatic reprogramming and revealed two novel top hits not previously associated with stemness acquisition: SHROOM3 and CSRP1. scRNA-seq was performed on reprogramming fibroblasts and A549 cells with SHROOM3 and CSRP1 knockdowns, respectively. Adhesome expression knockdown in both reprogramming models decreased PCP and EMT signatures, increased stemness acquisition, and, as revealed by CellChat inferred communication patterns, utilized similar cell-environment signaling during stemness acquisition. Furthermore, trajectory inference of the adhesome gene knockdown in both reprogramming models revealed novel pathways to stem-like states and cell fate transitions. Together, our findings support the adhesome as a novel target during somatic and oncogenic dedifferentiation for the development of more effective stem cell therapies and cancer treatments.