Merkel cells are specialized touch-sensing cells in the skin that detect gentle pressure and support fine motor skills. They are sparsely distributed in the basal layer of the epidermis and are concentrated in sensitive areas such as whiskers or fingertips. Despite their important function, our understanding of their development is limited, particularly in humans, largely due to the lack of validated in vitro culture systems. Our guests today created new lab models to study Merkel cells using mouse whisker tissue cultures, mouse skin organoids, and human skin organoids. These models allowed them to study Merkel cells as they develop, validate the role of known signaling pathways, and even identify some new ones. Their work provides easier access to Merkel cells for future studies including disease models to understand the pathophysiology of these cells.  

Human pluripotent stem cells (hPSCs) are transforming the study of biology and disease by enabling scientists to grow large amounts of specific cell types in the lab that were once difficult to obtain. Our guests today focus on improving the derivation and study of sensory neurons, which are sparse and diverse nerve cells near the spine that carry information like pain, touch, or position of the body to the brain. Damage to these neurons or sensory neuropathies, as can happen in diabetes or infections, is estimated to affect millions of people worldwide, yet treatments are limited. To improve the generation of human sensory neurons, the authors developed a genetic toolkit to fluorescently label these individual cells and their subtypes. This approach enables more precise study of these subtypes, their roles in disease, and potentially the development of treatments for sensory neuropathies.