A sensor array of cross-reactive polyion complexes enabled markerless and noninvasive identification of osteogenic and adipogenic differentiation of human mesenchymal stem cells.

Lineage commitment of stem cells is mainly regulated by their microenvironments, which comprise soluble growth factors, extracellular matrix, mechanical forces, and cell density. Although numerous studies have investigated stem cell response to these factors in two-dimensional (2D) culture, little is known about that in 3D culture. Here, we studied effects of 3D cell accumulation levels on the differentiation behavior of mesenchymal stem cells (MSCs) by using a micropatterned surface. After induction of 3D-cultured MSCs on the surface, their osteogenic differentiation was significantly promoted, while adipogenic differentiation was not. This differentiation behavior of densely packed MSCs in 3D culture is unlike that in 2D culture. Moreover, to determine the contributing factor of this commitment, the relationship between 3D cell accumulation levels and their differentiation potential was studied before differentiation induction. A series of MSCs with varied 3D accumulation levels were constructed on the micropatterned surface, where the accumulated MSCs were not in hypoxic environment. Interestingly, with increasing 3D accumulation levels, MSCs enhanced their osteogenic potential but repressed adipogenic potential in the gene expression level. These results suggest that preconditioned 3D microenvironments with high cell accumulation levels promote osteogenic differentiation of MSCs and their accumulation levels help in regulating MSC differentiation.

No abstract

The genetic structure of Streaked Shearwater Calonectris leucomelas, a seabird breeding on islands around Japan, was investigated using nuclear microsatellite markers at four breeding colonies located in three geographically distinct areas (Pacific Ocean, Sea of Japan, and Seto Inland Sea). To investigate independently natal and breeding dispersal patterns, we analyzed records of recoveries of birds banded around Japan over a 30-year period from 1971 to 2020. The genetic marker analysis showed little differentiation among the breeding sites and a lack of population structure. In contrast, banding data presented few examples of natal and breeding dispersal and a much greater number of natal/breeding philopatry cases. Although further research is needed to understand the discrepancy between the genetic properties and recapture patterns of banded birds, some possible reasons are suggested: actual dispersal events may not have been fully detected by the banding research, thus, underestimating dispersal frequency; rare dispersal events may have functioned to reduce the genetic structure; and/or breeding colonies of this species might have been established recently, thus genetic markers may not be indicative of current dispersal patterns. In conclusion, our results indicate ongoing gene flow and/or strong historical association in this species.