Volumetric analysis of the terminal ductal lobular unit architecture and cell phenotypes in the human breast

Abstract

The major lactiferous ducts of the human breast branch out and ultimately end at terminal ductal lobular units (TDLUs). These glandular structures are the source of milk upon lactation, and also the most common origin of breast cancer. Despite their functional and clinical importance, the three dimensional (3D) architecture of TDLUs has remained undetermined, largely due to their absence in rodent animal models. By utilizing recent technological advances in optical tissue clearing and microscopy, we imaged the 3D structure of healthy human breast tissue to determine whether general branching patterns or cell type specific niches exist in the TDLU. Our data demonstrate that TDLUs have a consistent shape and their branch parameters are largely comparable between different TDLUs and individuals irrespective of age or parity. Simulation of TDLU branching morphogenesis in 3D by mathematical modelling suggests that evolutionarily conserved mechanisms regulate mammary gland branching in humans and mice, despite their anatomical differences. The data also demonstrate a new level of organization within the TDLU structure identifying a main branch that dominates in bifurcation events and exhibits a more duct-like keratin expression pattern. In all, our data provide the first structural insights into 3D human breast anatomy and branching, and exemplify the power of volumetric imaging in deeper understanding of human breast biology.

Mechanoresponse of Curved Epithelial Monolayers Lining Bowl‐Shaped 3D Microwells

“…Our findings revealed that as the bowl-shaped microwell radius increased from 25 to 100 μm, the Gaussian curvature at the microwell entrance decreased from ≈ −10 −2 to −10 −3 μm −1 (Figure 2d). Importantly, we demonstrated a strong correspondence between this range of Gaussian curvatures and the typical values of Gaussian curvature observed in anatomic lobular structures within the lung, [23] kidney, [24] breast, [25] and pancreas [12] (Figure 2e). Our findings underscore therefore the clinical relevance of bowl-shaped microwells to investigate the mechanoresponse of curved epithelial monolayers that line lobular structures.…”

“…To get further insight into this phenomenon, we used a MDCK cell line expressing red fluorescent E-cadherin at Each point corresponds to one replicate with n ≥ 5 microwells per replicate. E) Typical Gaussian curvatures in the lobular structures of four human organs: lung (in green), kidney [23,24] (in orange), breast [25] (in purple), and pancreas [12] (in blue).…”

“…D) Gaussian curvature at the entrance of microwells with radius of 20 μm (in purple), 30 μm (in blue), 65 μm (in red), and 100 μm (in green).Each point corresponds to one replicate with n ≥ 5 microwells per replicate. E) Typical Gaussian curvatures in the lobular structures of four human organs: lung (in green), kidney[23,24] (in orange), breast[25] (in purple), and pancreas[12] (in blue).…”

Evolutionary graph theory on rugged fitness landscapes

“…The recent influx of spatially-resolved studies is starting to give us unprecedented access to molecular and cellular patterns of spatial organization (Xia et al, 2019;Galeano Niño et al, 2022;Ratz et al, 2022;Rodriques et al, 2019;Zhao et al, 2022;Erickson et al, 2022;Lomakin et al, 2022;Peurla et al, 2023;Gomariz et al, 2018;Rindone et al, 2021;Rendeiro et al, 2021;Goltsev et al, 2018;Mondragón-Palomino et al, 2022). While classic models in population genetic theory have been extraordinarily important for producing initial testable predictions about the role of space and structure in evolution, most previous modeling approaches represent spatial structure as a small number of distinct patches, symmetrically connected by migration corridors (Wright, 1943;Kimura and Weiss, 1964;Carja et al, 2014;Maruyama, 1970a;Slatkin, 1981;Whitlock and Barton, 1997;Whitlock, 2003;Wakeley, 2000;Durrett and Levin, 1994;Whitlock et al, 1995;Petkova et al, 2016;Gutenkunst et al, 2009;Jackson et al, 2020).…”