Core Insights - The research team led by Dr. Bai Bing from Kunming University of Science and Technology has collaborated with domestic and international researchers to resolve the "WNT signal gradient paradox" that has troubled developmental biology for 20 years, and has created an in vitro model of a gastric organoid that includes both the fundus and antrum regions, providing a new research platform for understanding human gastric organ development [1][2] Group 1 - The gastric organ, as a crucial digestive organ, has its functional regions, the fundus and antrum, formed as early as the 5th week of embryonic development [1] - The classical theory of developmental biology posits that organ patterning along the anterior-posterior axis relies on an increasing WNT signal gradient, while gastric development exhibits a decreasing WNT signal distribution, leading to the identified paradox [1] - The research team proposed the "hidden signaling center" hypothesis, suggesting the existence of undiscovered WNT signaling regulatory sources in gastric development [1][2] Group 2 - Through bioinformatics analysis, the team identified neural tissue as a key breakthrough, constructing a three-dimensional culture system that simulates the in vivo environment [2] - The team successfully induced pluripotent stem cells to develop a gastric organoid model with a bipolar distribution of fundus and antrum, which closely resembles the early human gastric organ at the molecular, cellular, and tissue structural levels [2] - The model visually demonstrates the asymmetric development process of the gastric anterior-posterior axis for the first time [2] Group 3 - Experimental validation confirmed that neural tissue, through its asymmetric geometric relationship with gastric epithelial tissue, forms a decreasing WNT signal gradient along the anterior-posterior axis, acting as a signaling center for gastric region development [2] - The epithelial-derived NR2F2 gene was identified as a critical regulatory factor for gastric tissue patterning, with its absence leading to an imbalance in fundus-antrum development, providing new insights into the mechanisms of gastric diseases [2] - This research enhances the classical signaling center theory in developmental biology and establishes the first in vitro research platform that simulates early human gastric organ development, addressing ethical limitations related to the scarcity of human embryonic samples [2]