Development and Characterization of Bioinspired Lipid Raft Nanovesicles for Therapeutic Applications

Lipid rafts are highly ordered regions of the plasma membrane enriched in signaling proteins and lipids. Their biological potential is realized in exosomes, a subclass of extracellular vesicles (EVs) that originate from the lipid raft domains. Previous studies have shown that EVs derived from human placental mesenchymal stromal cells (PMSCs) possess strong neuroprotective and angiogenic properties. However, clinical translation of EVs is challenged by very low, impure, and heterogeneous yields. Therefore, in this study, lipid rafts are validated as a functional biomaterial that can recapitulate the exosomal membrane and then be synthesized into biomimetic nanovesicles. Lipidomic and proteomic analyses show that lipid raft isolates retain functional lipids and proteins comparable to PMSC-EV membranes. PMSC-derived lipid raft nanovesicles (LRNVs) are then synthesized at high yields using a facile, extrusion-based methodology. Evaluation of biological properties reveals that LRNVs can promote neurogenesis and angiogenesis through modulation of lipid raft-dependent signaling pathways. A proof-of-concept methodology further shows that LRNVs could be loaded with proteins or other bioactive cargo for greater disease-specific functionalities, thus presenting a novel type of biomimetic nanovesicles that can be leveraged as targeted therapeutics for regenerative medicine.

Bioengineering Extracellular Vesicles for the Treatment of Cardiovascular Diseases

Cardiovascular diseases (CVD) remain one of the leading causes of mortality worldwide. Despite recent advances in diagnosis and interventions, there is still a crucial need for new multifaceted therapeutics that can address the complicated pathophysiological mechanisms driving CVD. Extracellular vesicles (EVs) are nanovesicles that are secreted by all types of cells to transport molecular cargo and regulate intracellular communication. EVs represent a growing field of nanotheranostics that can be leveraged as diagnostic biomarkers for the early detection of CVD and as targeted drug delivery vesicles to promote cardiovascular repair and recovery. Though a promising tool for CVD therapy, the clinical application of EVs is limited by the inherent challenges in EV isolation, standardization, and delivery. Hence, this review will present the therapeutic potential of EVs and introduce bioengineering strategies that augment their natural functions in CVD.

Exosomal microRNAs from mesenchymal stem/stromal cells: Biology and applications in neuroprotection

Mesenchymal stem/stromal cells (MSCs) are extensively studied as cell-therapy agents for neurological diseases. Recent studies consider exosomes secreted by MSCs as important mediators for MSCs’ neuroprotective functions. Exosomes transfer functional molecules including proteins, lipids, metabolites, DNAs, and coding and non-coding RNAs from MSCs to their target cells. Emerging evidence shows that exosomal microRNAs (miRNAs) play a key role in the neuroprotective properties of these exosomes by targeting several genes and regulating various biological processes. Multiple exosomal miRNAs have been identified to have neuroprotective effects by promoting neurogenesis, neurite remodeling and survival, and neuroplasticity. Thus, exosomal miRNAs have significant therapeutic potential for neurological disorders such as stroke, traumatic brain injury, and neuroinflammatory or neurodegenerative diseases and disorders. This review discusses the neuroprotective effects of selected miRNAs (miR-21, miR-17-92, miR-133, miR-138, miR-124, miR-30, miR146a, and miR-29b) and explores their mechanisms of action and applications for the treatment of various neurological disease and disorders. It also provides an overview of state-of-the-art bioengineering approaches for isolating exosomes, optimizing their yield and manipulating the miRNA content of their cargo to improve their therapeutic potential.

Extracellular Matrix Mimicking Nanofibrous Scaffolds Modified With Mesenchymal Stem Cell-Derived Extracellular Vesicles for Improved Vascularization

The network structure and biological components of natural extracellular matrix (ECM) are indispensable for promoting tissue regeneration. Electrospun nanofibrous scaffolds have been widely used in regenerative medicine to provide structural support for cell growth and tissue regeneration due to their natural ECM mimicking architecture, however, they lack biological functions. Extracellular vesicles (EVs) are potent vehicles of intercellular communication due to their ability to transfer RNAs, proteins, and lipids, thereby mediating significant biological functions in different biological systems. Matrix-bound nanovesicles (MBVs) are identified as an integral and functional component of ECM bioscaffolds mediating significant regenerative functions. Therefore, to engineer EVs modified electrospun scaffolds, mimicking the structure of the natural EV-ECM complex and the physiological interactions between the ECM and EVs, will be attractive and promising in tissue regeneration. Previously, using one-bead one-compound (OBOC) combinatorial technology, we identified LLP2A, an integrin α4β1 ligand, which had a strong binding to human placenta-derived mesenchymal stem cells (PMSCs). In this study, we isolated PMSCs derived EVs (PMSC-EVs) and demonstrated they expressed integrin α4β1 and could improve endothelial cell (EC) migration and vascular sprouting in an ex vivo rat aortic ring assay. LLP2A treated culture surface significantly improved PMSC-EV attachment, and the PMSC-EV treated culture surface significantly enhanced the expression of angiogenic genes and suppressed apoptotic activity. We then developed an approach to enable "Click chemistry" to immobilize LLP2A onto the surface of electrospun scaffolds as a linker to immobilize PMSC-EVs onto the scaffold. The PMSC-EV modified electrospun scaffolds significantly promoted EC survival and angiogenic gene expression, such as KDR and TIE2, and suppressed the expression of apoptotic markers, such as caspase 9 and caspase 3. Thus, PMSC-EVs hold promising potential to functionalize biomaterial constructs and improve the vascularization and regenerative potential. The EVs modified biomaterial scaffolds can be widely used for different tissue engineering applications.

Engineering Extracellular Vesicles as Nanotherapeutics for Regenerative Medicine

Long thought of to be vesicles that primarily recycled waste biomolecules from cells, extracellular vesicles (EVs) have now emerged as a new class of nanotherapeutics for regenerative medicine. Recent studies have proven their potential as mediators of cell proliferation, immunomodulation, extracellular matrix organization and angiogenesis, and are currently being used as treatments for a variety of diseases and injuries. They are now being used in combination with a variety of more traditional biomaterials and tissue engineering strategies to stimulate tissue repair and wound healing. However, the clinical translation of EVs has been greatly slowed due to difficulties in EV isolation and purification, as well as their limited yields and functional heterogeneity. Thus, a field of EV engineering has emerged in order to augment the natural properties of EVs and to recapitulate their function in semi-synthetic and synthetic EVs. Here, we have reviewed current technologies and techniques in this growing field of EV engineering while highlighting possible future applications for regenerative medicine.

The association between maternal serious psychological distress and child obesity at 3 years: a cross-sectional analysis of the UK Millennium Cohort Data

BACKGROUND

  The prevalence of child obesity is increasing rapidly worldwide. Early childhood has been identified as a critical time period for the development of obesity. Maternal mental health and early life environment are crucial factors and have been linked to adverse child outcomes. The objective of the study was to examine the relationship between maternal serious psychological distress and obesity in early childhood.

METHODS

  A cross-sectional analysis of data from the Millennium Cohort Study was conducted. Subjects consisted of all natural mothers (n= 10 465) who had complete and plausible data for Kessler-6 scores, socio-demographic and anthropometric variables, and their children for whom anthropometric measurements were completed at age 3. Maternal serious psychological distress was defined as a score of 13 or more on the Kessler-6 scale. Obesity was defined as body mass index ≥95th centile of the 1990 reference chart for age and sex in children. The data were analysed using spss 16. Maternal socio-demographic factors that are known to influence maternal mental health and child obesity were identified and adjusted using multivariate logistic regression.

RESULTS

  Of the 10 465 mother-child dyads, 3.5% of mothers had serious psychological distress and 5.5% of children were obese at 3 years of age. Logistic regression analysis showed that maternal serious psychological distress was associated with early childhood obesity (P= 0.01; OR 1.62, 95% CI 1.11, 2.37). After adjusting for potential confounding factors using multivariate logistic regression, maternal serious psychological distress remained significantly associated with early childhood obesity (P= 0.01; OR 1.59, 95% CI 1.08, 2.34).

CONCLUSIONS

  The results show that maternal serious psychological distress is independently associated with early childhood obesity.

The impacts of a school closure on neighbourhood social cohesion: narratives from Invercargill, New Zealand

We propose that, beyond their educational function, schools can serve as catalysts for community participation, social cohesion and the vitality of neighbourhoods. The paper explores the impacts of a school closure on families in an urban neighbourhood in Invercargill, New Zealand. The highest urban depopulation rate in the country has had implications for the viability of Invercargill schools. We present a qualitative study of narratives gathered during an interview-based study of the closure of Surrey Park School. Our analysis highlights the impact of school closure for low-income families and more generally reflects on the place of schools in contributing to social cohesion and the broadly defined health of a community.

Participatory environmental health research in Aotearoa/New Zealand: constraints and opportunities

Within the Aotearoa/New Zealand context, this article identifies opportunities for, as well as constraints on, using participatory research to address environmental health concerns. In New Zealand, principles of partnership fundamental to the Treaty of Waitangi, and the requirements for consultation within the Resource Management Act, provide a framework for participatory approaches. Participatory environmental health research integrates knowledge from various scientific and community sources. It also fosters the innovation, evaluation, and sharing of information that new public health approaches demand. As an emerging field in Aotearoa/New Zealand, it must draw on experience from resource management, rural development, and public health research and practice. Water quality is used as an example of the complexity of environmental health issues and of the potential benefits of engaging stakeholders where long-term health and well-being require balancing ecosystem integrity, economic viability, and social processes.