Biology subjects

Pinho, S.

Publications and source records attributed to Pinho, S..

2 recordsLinked to original sources

bioRxiv2023

Periosteal skeletal stem cells can migrate into the bone marrow and support hematopoiesis after injury

Skeletal stem cells have been isolated from various tissues, including periosteum and bone marrow, where they exhibit key functions in bone biology and hematopoiesis, respectively. The role of periosteal skeletal stem cells in bone regeneration and healing has been extensively studied, but their ability to contribute to the bone marrow stroma is still under debate. In the present study, we characterized a whole bone transplantation model that mimics the initial bone marrow necrosis and fatty infiltration seen after injury. Using this model and a lineage tracing approach, we observed the migration of periosteal skeletal stem cells into the bone marrow after transplantation. Once in the bone marrow, periosteal skeletal stem cells are phenotypically and functionally reprogrammed into bone marrow mesenchymal stem cells that express high levels of hematopoietic stem cell niche factors such as Cxcl12 and Kitl. In addition, using ex vivo and in vivo approaches, we found that periosteal skeletal stem cells are more resistant to acute stress than bone marrow mesenchymal stem cells. These results highlight the plasticity of periosteal skeletal stem cells and their potential role in bone marrow regeneration after bone marrow injury.

cell biology↗

bioRxiv2021

Computer-Vision Stabilized Intravital Imaging Reveals Lung Capillary Neutrophil Dynamics Crucial for Lung Host-Defense Function

Polymorphonuclear neutrophils (PMN) are highly dynamic innate immune cells which are essential for lung host defense. However, in vivo intravital imaging in moving organs such as the lung remains challenging due to motion artifacts. Here we describe a novel intravital imaging method with high-throughput analytical capability based on a computer vision stabilization algorithm, Computer-vision-Assisted STabilized intravital imaging (CASTii). The sub-micron precision of this approach enables analysis of compartmentalized intravital PMN dynamics. We quantified in real-time a novel patrolling function of lung intracapillary circulating PMN. We also describe the dynamics of intracapillary PMN pooling (marginated PMN pool) using direct imaging of PMNs. The pool was formed by repeated catch-and-release kinetics involving PMN deformation inside microvessels during the passage of PMNs in vessels. We observed rapid PMN recruitment into the lung tissue compartments from pooled PMNs in response to alveolar chemoattract exposure. In contrast, endotoxemia-induced intracapillary sequestration of PMN impaired PMN transmigration into the alveolar space and defective phagocytosis of live bacteria. Intravital imaging of PMN dynamics with CASTii provides fundamental insights into host-defense functions of lung capillary PMN.

microbiology↗