Quantification of the Extracellular Matrix Molecule Thrombospondin 1 and Its Pericellular Association in the Brain Using a Semiautomated Computerized Approach

Strategic outline of interventions targeting extracellular matrix for promoting healthy longevity

The extracellular matrix (ECM), composed of interlinked proteins outside of cells, is an important component of the human body that helps maintain tissue architecture and cellular homeostasis. As people age, the ECM undergoes changes that can lead to age-related morbidity and mortality. Despite its importance, ECM aging remains understudied in the field of geroscience. In this review, we discuss the core concepts of ECM integrity, outline the age-related challenges and subsequent pathologies and diseases, summarize diagnostic methods detecting a faulty ECM, and provide strategies targeting ECM homeostasis. To conceptualize this, we built a technology research tree to hierarchically visualize possible research sequences for studying ECM aging. This strategic framework will hopefully facilitate the development of future research on interventions to restore ECM integrity, which could potentially lead to the development of new drugs or therapeutic interventions promoting health during aging.

Characterization of gene expression changes in human neural stem cells and endothelial cells modeling a neurovascular microenvironment

Angiogenesis-mediated neovascularization correlates with recovery after intracerebral implantation of neural stem cells (NSCs) in stroke. To elucidate NSCs' mechanism of action, it is essential to understand how these interact with the brain's vasculature after implantation. Using an all-human endothelial cell (EC, D3 cell line) and NSC (STROC05 and CTXOE03) co-culture model, fluorescently activated cell sorting (FACS) was used to isolate each cell type for a comparison of gene expression between monocultures of undifferentiated proliferating and differentiated non-proliferating cells. Gene expression for angiogenic factors (vascular endothelial growth factor, platelet derived growth factor, angiopoietin), as well as cell survival (brain derived neurotrophic factor, fibroblast growth factor) and migration (stromal cell-derived factor-1a) were measured and contrasted with the corresponding receptors on each cell type. The cellular source of extracellular matrix defining the basement membrane (vitronectin, fibronectin, laminin, collagen I and IV) and neuropil (hyaluronic acid, aggrecan, neurocan, thrombospondin, nidogen and brain associated link protein-1) was evaluated for NSCs and ECs. Co-culturing dramatically changed the expression profiles of each cell type in comparison to undifferentiated, but also differentiated cells. These results indicate that monocultures provide a poor model to investigate the cellular signaling involved in a tissue repair response. Co-cultures of NSCs and ECs forming vasculature-like structures (VLS) provide a more complex model to investigate NSC-induced neovascularization. These in vitro studies are essential to tease out individual cell signaling in NSCs and ECs to develop a mechanistic understanding of the efficacy of NSCs as a therapeutic for stroke.

Minimally Invasive Delivery of Microbeads with Encapsulated, Viable and Quiescent Neural Stem Cells to the Adult Subventricular Zone

Stem cell therapies demonstrate promising results as treatment for neurological disease and injury, owing to their innate ability to enhance endogenous neural tissue repair and promote functional recovery. However, delivery of undifferentiated and viable neuronal stem cells requires an engineered delivery system that promotes integration of transplanted cells into the inflamed and cytotoxic region of damaged tissue. Within the brain, endothelial cells (EC) of the subventricular zone play a critical role in neural stem cell (NSC) maintenance, quiescence and survival. Therefore, here, we describe the use of polyethylene glycol microbeads for the coincident delivery of EC and NSC as a means of enhancing appropriate NSC quiescence and survival during transplantation into the mouse brain. We demonstrate that EC and NSC co-encapsulation maintained NSC quiescence, enhanced NSC viability, and facilitated NSC extravasation in vitro, as compared to NSC encapsulated alone. In addition, co-encapsulated cells delivered to an in vivo non-injury model reduced inflammatory response compared to freely injected NSC. These results suggest the strong potential of a biomimetic engineered niche for NSC delivery into the brain following neurological injury.