Mesendodermlike

Mesendodermlike refers to a cellular state resembling the mesendoderm, a transient progenitor population during vertebrate gastrulation that gives rise to both mesoderm and endoderm. In developmental biology and stem cell research, the term describes cells that express markers of both lineages and have mixed differentiation potential.

In embryos, mesendoderm arises during the primitive streak; signaling from Nodal/Activin and WNT pathways directs bipotential fate. Mesendodermlike states are transitional between the epiblast and definitive mesoderm/endoderm.

Markers commonly associated with mesendodermlike cells include MIXL1, EOMES, and BRACHYURY (T) with SOX17 and FOXA2; sometimes goosecoid. Expression patterns show co-expression of mesodermal and endodermal programs.

In human pluripotent stem cell differentiation, WNT activation plus Activin/Nodal can generate mesendoderm-like populations, used as intermediates to direct toward mesoderm or endoderm lineages. They serve as a surrogate model for early gastrulation and can improve directed differentiation yields.

Mesendodermlike states are transient and context-dependent; misregulation can lead to aberrant differentiation. They provide insights into early development and disease modeling but must be carefully interpreted in culture.