CD68 Identified as a Regulator of Human Melanocyte Development and Function.

This study establishes CD68, conventionally known as a macrophage marker, as a regulator of melanocyte biology. Using a human embryonic stem cell (hESC) differentiation model that replicates neural crest-derived melanocyte development, we performed single-cell RNA sequencing across five critical developmental timepoints (day 0, 6, 9, 11, and 25) to construct a comprehensive transcriptional atlas of melanocyte differentiation. Application of the Single-cell Orientation Tracing (SOT) algorithm revealed CD68 as a previously unrecognized component of the melanogenesis, showing coordinated expression with core regulators including MITF, TYR, and TYRP1. Functional validation demonstrated that CD68 knockdown significantly impairs melanin synthesis, cell proliferation, and MAPK pathway activation. Together, these findings redefine the biological significance of CD68 beyond its classical association with immune cells, identifying CD68 as a component of the melanogenic regulatory network. This work provides significant insights for understanding melanocyte development and highlights CD68 as a potential therapeutic target for pigmentary disorders.