Bone formation by human paediatric marrow stromal cells in a functional allogeneic immune system.

Allogeneic stem-cell based regenerative medicine is a promising approach for bone defect repair. The use of chondrogenically differentiated human marrow stromal cells (MSCs) has been shown to lead to bone formation by endochondral ossification in immunodeficient pre-clinical models. However, an insight into the interactions between the allogeneic immune system and the human MSC-derived bone grafts has not been fully achieved yet.

In Vitro Mineralisation of Tissue-Engineered Cartilage Reduces Endothelial Cell Migration, Proliferation and Tube Formation.

Tissue engineering bone via endochondral ossification requires the generation of a cartilage template which undergoes vascularisation and remodelling. While this is a promising route for bone repair, achieving effective cartilage vascularisation remains a challenge. Here, we investigated how mineralisation of tissue-engineered cartilage affects its pro-angiogenic potential.

Chondrogenically Primed Human Mesenchymal Stem Cells Persist and Undergo Early Stages of Endochondral Ossification in an Immunocompetent Xenogeneic Model.

Tissue engineering approaches using progenitor cells such as mesenchymal stromal cells (MSCs) represent a promising strategy to regenerate bone. Previous work has demonstrated the potential of chondrogenically primed human MSCs to recapitulate the process of endochondral ossification and form mature bone , using immunodeficient xenogeneic models. To further the translation of such MSC-based approaches, additional investigation is required to understand the impact of interactions between human MSC constructs and host immune cells upon the success of MSC-mediated bone formation.

Nano-ghosts: Novel biomimetic nano-vesicles for the delivery of antisense oligonucleotides.

Antisense oligonucleotides (ASOs) carry an enormous therapeutic potential in different research areas, however, the lack of appropriate carriers for their delivery to the target tissues is hampering their clinical translation. The present study investigates the application of novel biomimetic nano-vesicles, Nano-Ghosts (NGs), for the delivery of ASOs to human mesenchymal stem cells (MSCs), using a microRNA inhibitor (antimiR) against miR-221 as proof-of-concept. The integration of this approach with a hyaluronic acid-fibrin (HA-FB) hydrogel scaffold is also studied, thus expanding the potential of NGs applications in regenerative medicine.

Endothelium-derived stromal cells contribute to hematopoietic bone marrow niche formation.

Bone marrow stromal cells (BMSCs) play pivotal roles in tissue maintenance and regeneration. Their origins, however, remain incompletely understood. Here we identify rare LNGFR cells in human fetal and regenerative bone marrow that co-express endothelial and stromal markers.

Drug delivery in intervertebral disc degeneration and osteoarthritis: Selecting the optimal platform for the delivery of disease-modifying agents.

Osteoarthritis (OA) and intervertebral disc degeneration (IVDD) as major cause of chronic low back pain represent the most common degenerative joint pathologies and are leading causes of pain and disability in adults. Articular cartilage (AC) and intervertebral discs are cartilaginous tissues with a similar biochemical composition and pathophysiological aspects of degeneration. Although treatments directed at reversing these conditions are yet to be developed, many promising disease-modifying drug candidates are currently under investigation.

Hydrogel-based delivery of antimiR-221 enhances cartilage regeneration by endogenous cells.

Articular cartilage is frequently injured by trauma or osteoarthritis, with limited and inadequate treatment options. We investigated a new strategy based on hydrogel-mediated delivery of a locked nucleic acid microRNA inhibitor targeting miR-221 (antimiR-221) to guide in situ cartilage repair by endogenous cells. First, we showed that transfection of antimiR-221 into human bone marrow-derived mesenchymal stromal cells (hMSCs) blocked miR-221 expression and enhanced chondrogenesis in vitro.

Targeting anti-chondrogenic factors for the stimulation of chondrogenesis: A new paradigm in cartilage repair.

Trauma and age-related cartilage disorders represent a major global cause of morbidity, resulting in chronic pain and disability in patients. A lack of effective therapies, together with a rapidly aging population, creates an impressive clinical and economic burden on healthcare systems. In this scenario, experimental therapies based on transplantation or in situ stimulation of skeletal Mesenchymal Stem/progenitor Cells (MSCs) have raised great interest for cartilage repair.

Dedifferentiated Chondrocytes in Composite Microfibers As Tool for Cartilage Repair.

Tissue engineering (TE) approaches using biomaterials have gain important roles in the regeneration of cartilage. This paper describes the production by microfluidics of alginate-based microfibers containing both extracellular matrix (ECM)-derived biomaterials and chondrocytes. As ECM components gelatin or decellularized urinary bladder matrix (UBM) were investigated.

Emerging potential of gene silencing approaches targeting anti-chondrogenic factors for cell-based cartilage repair.

The field of cartilage repair has exponentially been growing over the past decade. Here, we discuss the possibility to achieve satisfactory regeneration of articular cartilage by means of human mesenchymal stem cells (hMSCs) depleted of anti-chondrogenic factors and implanted in the site of injury. Different types of molecules including transcription factors, transcriptional co-regulators, secreted proteins, and microRNAs have recently been identified as negative modulators of chondroprogenitor differentiation and chondrocyte function.

Establishment of a 3D-dynamic osteoblasts-osteoclasts co-culture model to simulate the jawbone microenvironment in vitro.

Aims: We aimed to establish a 3D osteoblasts/osteoclasts co-culture system requiring limited amounts of human primary cells and useful as platform to 1. recapitulate an "oral bone microenvironment" in healthy or pathological condition, and 2. produce potential implantable cell constructs for regeneration of jawbone which can be negatively affected by bisphosphonates (BPs).

Silencing of Antichondrogenic MicroRNA-221 in Human Mesenchymal Stem Cells Promotes Cartilage Repair In Vivo.

There is a growing demand for the development of experimental strategies for efficient articular cartilage repair. Current tissue engineering-based regenerative strategies make use of human mesenchymal stromal cells (hMSCs). However, when implanted in a cartilage defect, control of hMSCs differentiation toward the chondrogenic lineage remains a significant challenge.

Pro-chondrogenic effect of miR-221 and slug depletion in human MSCs.

In this study we have inhibited the expression of two negative regulators of chondrogenesis, Slug transcription factor (TF) and the small non-coding single stranded RNA microRNA-221 (miR-221), in human mesenchymal stem cells (MSCs). Our aim was test a new approach to guide the cells toward a chondrocyte - like phenotype, without the employment of differentiating agents, in the prospect of their clinical applications for cell-based cartilage tissue engineering. We have characterized these manipulated cells by gene expression analysis at the RNA and protein levels.

Chondrogenic potential of Slug-depleted human mesenchymal stem cells.

The use of short interfering RNA (siRNA) in combination with stem cells and biocompatible scaffolds is a promising strategy in regenerative medicine. Our experimental strategy was to explore the possibility of forcing or guiding the chondrogenic differentiation of human mesenchymal stem cells (hMSCs) by knocking down a negative regulator of chondrogenesis, Slug transcription factor (TF), thus altering cell behavior. We found that TGFβ-driven chondrogenic differentiation of hMSCs cultured onto a hyaluronan-based scaffold, HYAFF(®)-11, was strengthened after cell exposure to siRNA against Slug.

Correlation between Slug transcription factor and miR-221 in MDA-MB-231 breast cancer cells.

Background: Breast cancer and its metastatic progression is mainly directed by epithelial to mesenchymal transition (EMT), a phenomenon supported by specific transcription factors and miRNAs.

Methods: In order to investigate a possible correlation between Slug transcription factor and miR-221, we performed Slug gene silencing in MDA-MB-231 breast cancer cells and evaluated the expression of genes involved in supporting the breast cancer phenotype, using qRT-PCR and Western blot analysis. Chromatin immunoprecipitation and wound healing assays were employed to determine a functional link between these two molecules.

Transcription factor decoy against NFATc1 in human primary osteoblasts.

The present study describes, for the first time, the removal of the nuclear factor of activated T cells cytoplasmic 1 (NFATc1) by a decoy approach in human primary osteoblasts (hOBs). hOBs with different NFATc1 expression levels were used. The functionality of endogenous NFAT proteins in our experimental model was analyzed by monitoring the transcriptional activity on a luciferase reporter construct driven by three copies of an NFAT response element (pNFAT-TA-luc).