Structure formation in mini-organs
The development of alveoli in organoids derived from mammary-gland tissue follows the same physical principles as the formation of discrete droplets in a water jet. Many of the organ systems found in animals exhibit highly complex structures, which are essential for their various functions. How such structures develop during embryonic development is a central question in biology. Together with the lab of Andreas Bausch(TUM) we investigated this fundamental problem using mini-organs termed organoids as their experimental system. Our focus was on the spherical ‘alveoli’ in which the ducts of the lactating mammary gland terminate. The study demonstrated in detail that these alveoli form according to the same principles as droplets in a jet of water emerging from a hose.
The experimental work was carried out in Bausch’s laboratory and used mammary-gland organoids grown in culture from excised human tissue. Organoids are three-dimensional model systems that exhibit many of the physiologically relevant properties of the organ from which they originated. Thus, mammary-gland organoids form ducts that branch into clusters of smaller tube-like structures, each of which ends in a spherical sac or alveolus. This architecture is typical of the lactating human mammary gland, but it is also found in many other organs including the lung. Bausch and his group succeeded for the first time in following the growth dynamics of the mini-organs over several days via time-lapse microscopy. In addition, they investigated the micromechanical response of the developing tissue to the localized, laser-induced ablation of cells.