Rationale: Stem cell-based tracheal replacement represents an emerging therapeutic option for patients with otherwise untreatable airway diseases including long-segment congenital tracheal stenosis and upper airway tumors. Clinical experience demonstrates that restoration of mucociliary clearance in the lungs after transplantation of tissue-engineered grafts is critical, with preclinical studies showing that seeding scaffolds with autologous mucosa improves regeneration. High epithelial cell-seeding densities are required in regenerative medicine, and existing techniques are inadequate to achieve coverage of clinically suitable grafts.Objectives: To define a scalable cell culture system to deliver airway epithelium to clinical grafts.Methods: Human respiratory epithelial cells derived from endobronchial biopsies were cultured using a combination of mitotically inactivated fibroblasts and Rho-associated protein kinase (ROCK) inhibition using Y-27632 (3T31Y). Cells were analyzed by immunofluorescence, quantitative polymerase chain reaction, and flow cytometry to assess airway stem cell marker expression. Karyotyping and multiplex ligation-dependent probe amplification were performed to assess cell safety. Differentiation capacity was tested in three-dimensional tracheospheres, organotypic cultures, air-liquid interface cultures, and an in vivo tracheal xenograft model. Ciliary function was assessed in air-liquid interface cultures.
Aging is associated with remodeling of the immune system to enable the maintenance of lifelong immunity. In the CD8 + T cell compartment, aging results in the expansion of highly differentiated cells that exhibit characteristics of cellular senescence. Here we found that CD27 − CD28 − CD8 + T cells lost the signaling activity of the T cell antigen receptor (TCR) and expressed a protein complex containing the agonistic natural killer (NK) receptor NKG2D and the NK adaptor molecule DAP12, which promoted cytotoxicity against cells that expressed NKG2D ligands. Immunoprecipitation and imaging cytometry indicated that the NKG2D-DAP12 complex was associated with sestrin 2. The genetic inhibition of sestrin 2 resulted in decreased expression of NKG2D and DAP12 and restored TCR signaling in senescent-like CD27 − CD28 − CD8 + T cells. Therefore, during aging, sestrins induce the reprogramming of non-proliferative senescent-like CD27 − CD28 − CD8 + T cells to acquire a broad-spectrum, innate-like killing activity.
MFP tends to underestimate ingestion of nutrients probably due to inadequacies in the MFP database. However, MFP showed good relative validity, especially for energy and fibre. Its use, as well as other similar applications, should be encouraged, due to ease of assessing dietary information, although careful usage is recommended because of database gaps.
Mesenchymal stromal cells (MSCs) are inherently tumor-homing and can be isolated, expanded and transduced, making them viable candidates for cell therapy. This tumor-tropism has been used to deliver anti-cancer therapies to various tumor models. In this study we sought to discover which molecules are the key effectors of human MSC tumor homing in vitro and using an in vivo murine model. Here we discover for the first time that Macrophage Migration Inhibitory Factor (MIF) is the key director of MSC migration and infiltration towards tumor cells. We have shown this major role for MIF using in vitro migration and invasion assays, in presence of different receptor inhibitors and achieving a drastic decrease in both processes using MIF inhibitor. Additionally, we demonstrate physical interaction between MIF and three receptors: CXCR2, CXCR4 and CD74. CXCR4 is the dominant receptor used by MIF in the homing tumor context, although some signaling is observed through CXCR2. We demonstrate downstream activation of the MAPK pathway necessary for tumor homing. Importantly we show that knock down of either CXCR4 or MIF abrogates MSC homing to tumors in an in vivo pulmonary metastasis model, confirming the in vitro 2D and 3D assays. This improved understanding of MSC tumor tropism will further enable development of novel cellular therapies for cancers.
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