Concept: Stromal cell
To investigate the impact of the androgen precursor dehydroepiandrosterone (DHEA) on the decidualization of human endometrial stromal cells isolated from women of advanced reproductive age.
In myeloid malignancies, the neoplastic clone outgrows normal hematopoietic cells toward BM failure. This event is also sustained by detrimental stromal changes, such as BM fibrosis and osteosclerosis, whose occurrence is harbinger of a dismal prognosis. We show that the matricellular protein SPARC contributes to the BM stromal response to myeloproliferation. The degree of SPARC expression in BM stromal elements, including CD146(+) mesenchymal stromal cells, correlates with the degree of stromal changes, and the severity of BM failure characterizing the prototypical myeloproliferative neoplasm primary myelofibrosis. Using Sparc(-/-) mice and BM chimeras, we demonstrate that SPARC contributes to the development of significant stromal fibrosis in a model of thrombopoietin-induced myelofibrosis. We found that SPARC deficiency in the radioresistant BM stroma compartment impairs myelofibrosis but, at the same time, associates with an enhanced reactive myeloproliferative response to thrombopoietin. The link betwen SPARC stromal deficiency and enhanced myeloid cell expansion under a myeloproliferative spur is also supported by the myeloproliferative phenotype resulting from the transplantation of defective Apc(min) mutant hematopoietic cells into Sparc(-/-) but not WT recipient BM stroma. Our results highlight a complex influence of SPARC over the stromal and hematopoietic BM response in myeloproliferative conditions.
The barrier membranes maintain a secluded space to prevent the ingrowth of connective tissue and direct the growth of new bone into a desired site; however, they do not stimulate or induce bone regeneration. To enhance the bone bioactivities of membranes, we developed chitosan electret membranes with bioelectricity by grid-controlled constant voltage corona charging. The electret membranes charged with heat treatment (HT electret membranes) exhibited superior electret charge storage stability than the ones charged without heat treatment (RT electret membranes). Human bone marrow stromal cells (hBMSCs) demonstrated better growth on HT electrets membrane. Moreover, hBMSCs osteoblastic differentiation was enhanced on HT electret membranes, as evidenced by osteocalcin and osteopontin expression as assessed by immunocytochemistry, quantitative RT-PCR and western blot analysis. The rabbit calvarial defect model demonstrated that HT electret membranes induced a significantly enhanced bone regeneration compared with RT electret membranes. New bone formation was found at both the periphery and in the center of the defects four weeks after implantation. These results indicated that the chitosan electret membrane has osteogenic potential and could be applied as a novel barrier membrane.
Pre-clinical evidence indicates that autologous bone marrow-derived mesenchymal stromal cell (BM-MSC) transplantation improves motor function in patients with central nervous system disorders.
Mesenchymal Stromal Cells (MSC), as advanced therapy products, must satisfy all the requirements for human use of medicinal products, aiming to maintain the quality and safety of the cells. The MSC manufacturing process for clinical use should comply with the principles of Good Manufacturing Practice (GMP). This ensures that cell preparations are produced and controlled, from the collection and manipulation of raw materials, through the processing of intermediate products, to the quality controls, storage, labelling and packaging, and release. The objective of this document is to provide the minimal quality requirements for the MSC production and its delivery for clinical use, so the safety of the final cell therapy product will not be compromised. For this purpose, the document evaluates the most important steps of GMP-compliant MSC production: the isolation and expansion process; the validation phase of the process, including all quality controls for the characterization, functionality, potency and safety of MSCs; the quality control at the batch release to guarantee the safety of patient infusion. This opinion paper reflects the consensus viewpoint of the authors and scientists participating the GISM Working Group*. * GISM Working Group includes the following individual investigators: Biagi E, Del Bue M, Frigerio S, Lisini D, Marazzi M, Mareschi K, Nava S, Parolini O, Riccobon A, Romagnoli L, Viganò M.
Rapid and efficient magnetization of human bone marrow stromal cells (BMSC) through functionalized magnetic nanoparticles (MNP).
Pre-transplant myeloablation is associated with marrow adipogenesis, resulting in delayed engraftment of hematopoietic stem cells (HSCs). This is strongly undesirable, especially when the donor HSCs are fewer in numbers or have compromised functionality. The molecular mechanisms behind irradiation-induced marrow adipogenesis have not been extensively investigated. Here we show that bone marrow (BM) cells, especially T-cells and stromal cells, express and secrete copious amounts of BMP4 in response to irradiation, which causes the bone marrow stromal cells to commit to adipocyte lineage, thereby contributing to an increase in bone marrow adipogenesis. We further demonstrate that Simvastatin inhibits the BMP4-mediated adipogenic commitment of marrow stromal cells by inhibiting Ppar-γ expression. Importantly, Simvastatin does not prevent BMP4 secretion by the BM cells, and thus does not interfere with its salutary role in post-transplant hematopoietic regeneration. Our data identify previously unknown mechanisms operative in marrow adipogenesis post-myeloablation. They also reveal the molecular mechanisms behind the advantage of using Simvastatin as a niche-targeting agent to improve HSC engraftment.
Pancreatic ductal adenocarcinomas (PDAs) are desmoplastic and can undergo epithelial-to-mesenchymal transition to confer metastasis and chemoresistance. Studies have demonstrated that phenotypically and functionally distinct stromal cell populations exist in PDAs. Fibroblast activation protein-expressing (FAP-expressing) cells act to enhance PDA progression, while α-smooth muscle actin myofibroblasts can restrain PDA. Thus, identification of precise molecular targets that mediate the protumorigenic activity of FAP+ cells will guide development of therapy for PDA. Herein, we demonstrate that FAP overexpression in the tumor microenvironment correlates with poor overall and disease-free survival of PDA patients. Genetic deletion of FAP delayed onset of primary tumor and prolonged survival of mice in the KPC mouse model of PDA. While genetic deletion of FAP did not affect primary tumor weight in advanced disease, FAP deficiency increased tumor necrosis and impeded metastasis to multiple organs. Lineage-tracing studies unexpectedly showed that FAP is not only expressed by stromal cells, but can also be detected in a subset of CD90+ mesenchymal PDA cells, representing up to 20% of total intratumoral FAP+ cells. These data suggest that FAP may regulate PDA progression and metastasis in cell-autonomous and/or non-cell-autonomous fashions. Together, these data support pursuing FAP as a therapeutic target in PDA.
Repair of large bone defects remains a significant clinical challenge. Bone marrow stromal cells (BMSCs), a subset of which is known as bone marrow-derived mesenchymal stem cells, show therapeutic potential for bone regeneration. However, their isolation, expansion and implantation will need to be conducted under good manufacturing practices (GMP) at separate locations. An investigation which mimics this clinical scenario where large bone defects shall be regenerated is required before clinical trials can be initiated.
: Age-related osteoporosis is driven by defects in the tissue-resident mesenchymal stromal cells (MSCs), a heterogeneous population of musculoskeletal progenitors that includes skeletal stem cells (SSCs). MSC decline leads to reduced bone formation, causing loss of bone volume and the breakdown of bony microarchitecture crucial to trabecular strength. Furthermore, the low-turnover state precipitated by MSC loss leads to low-quality bone that is unable to perform remodeling-mediated maintenance-replacing old damaged bone with new healthy tissue. Using minimally expanded exogenous MSCs injected systemically into a mouse model of human age-related osteoporosis, we show long-term engraftment and markedly increased bone formation. This led to improved bone quality and turnover and, importantly, sustained microarchitectural competence. These data establish proof of concept that MSC transplantation may be used to prevent or treat human age-related osteoporosis.