Neurons-derived extracellular vesicles promote neural differentiation of ADSCs: a model to prevent peripheral nerve degeneration

Understanding the mechanisms of disease modifying effects of aerobic exercise in people with Alzheimer's disease

Alzheimer's disease (AD) is a very disabling disease. Pathologically, it is characterized by the presence of amyloid plaques and neurofibrillary tangles in the brain that results in neurodegeneration. Its clinical manifestations include progressive memory impairment, language decline and difficulty in carrying out activities of daily living (ADL). The disease is managed using interventions such as pharmacological interventions and aerobic exercise. Use of aerobic exercise has shown some promises in reducing the risk of developing AD, and improving cognitive function and the ability to carry out both basic and instrumental ADL. Although, the mechanisms through which aerobic exercise improves AD are poorly understood, improvement in vascular function, brain glucose metabolism and cardiorespiratory fitness, increase in antioxidant capacity and haemoglobin level, amelioration of immune-related and inflammatory responses, modulation of concentration of circulating Neurotrophins and peptides and decrease in concentration of tau protein and cortisol level among others seem to be the possible mechanisms. Therefore, understanding these mechanisms is important to help characterize the dose and the nature of the aerobic exercise to be given. In addition, they may also help in finding ways to optimize other interventions such as the pharmacological interventions. However, more quality studies are needed to verify the mechanisms.

Effects of crocin on the enhancement of in vitro neurogenesis: Involvement of Notch and CREB/BDNF signaling pathways

Objectives

Adult neurogenesis, the process of generating new neurons, continues throughout life. Unfortunately, this process is insufficient in pathological conditions and needs to be promoted. Crocin, the active component of saffron, affects neurogenesis in vivo and in vitro. We aimed to investigate the enhancing effects of crocin on the neurogenesis of adipose-derived mesenchymal stem cells in the presence of retinoic acid, as well as the molecular pathways involved.

Materials and Methods

Differentiation capacities and stemness potential of harvested ADSCs were evaluated by differentiating into osteocytes and adipocytes, and expression of mesenchymal CD markers by flow cytometry. The optimum dose of crocin was assessed with an MTT assay. Crocin, retinoic acid, CREB/BDNF, and Notch inhibitors and their combination were added to the culture medium. Jag1, Hes1, Notch, and BDNF gene expression were analyzed by RT-PCR on days 7, 14, and 21, while CREB, DCX, SOX2, and NeuN expression were analyzed by immunofluorescence.

Results

Expression of mesenchymal CD markers as well as adipogenic and osteogenic differentiation confirmed the origin and properties of ADSCs. The optimal dose of crocin was 1 mM. Crocin significantly (P<0.05) increased, while inhibitors (DATP&Naphthol) significantly (P<0.05) decreased Jag1, Hes1, Notch, and BDNF expression. Immunofluorescent assessments showed that expression of DCX, BDNF, NeuN, and Sox2 proteins increased significantly (P<0.05) after crocin administration and decreased significantly (P<0.05) after inhibitor administration.

Conclusion

Crocin can be used as an enhancer for neural differentiation of MSCs in vitro in the presence of retinoic acid. The mechanism is proposed through Notch and CREB/BDNF signaling pathways.

Adipose and amnion-derived mesenchymal stem cells: Extracellular vesicles characterization and implication for reproductive biotechnology

The stem cell-based research for reproductive biotechnology has been widely studied and shows promise for repairing defective tissue or degenerated cells to treat different diseases. The adipose tissue and amniotic membrane have awakened great interest in regenerative medicine and arises as a promising source of mesenchymal stem cells. Both types, adipose and amniotic derived mesenchymal stem cells (AMSCs) are multipotent cells with an enhanced ability to differentiate into multiple lineages.. We aimed to evaluate the effect of basal supplementation of exosomes in cell cultures with canine amniotic mesenchymal stem cells (MSCs). Mesenchymal stem cells derived from canine amniotic and adipose tissue were isolated and cultured performing cell passages until 80-90% confluence was reached. The growth curve was determined and peak cell growth was observed in the second passage. The cells were then characterized and differentiated into adipogenic, chondrogenic and osteogenic lineages. Extracellular vesicles from amnion were isolated using an ultracentrifugation protocol and characterized by nanosight analysis. To evaluate their ability to improve cellular viability in naturally inefficient passages, exosomes were co-cultures to the MSC cells. The results showed a 15-20% increase in the expansion rate of cultures supplemented with vesicles extracted in the first and second passages when compared to the control group. Statistical analysis using the Dunnett test (p ≤ 0.05) corroborated this result, showing a positive correlation between supplementation and expansion rate. These results indicate not only the importance of exosomes in the cell communication process but also the feasibility of the culture supplementation protocol for therapeutic purposes. The potential of the AMSCs for reproductive biotechnology is undoubted, however, their application to repair reproductive disorders and the involved mechanisms remain elusive. The strategies to enable the Adipose Stem Cells and AMSCs application in reproductive biotechnology and optimize their use for tissue regeneration open new venues using exosomes interactions.

Effects of melatonin-pretreated adipose-derived mesenchymal stem cells (MSC) in an animal model of spinal cord injury

Background

One of the most serious nervous system diseases is spinal cord injury(SCI), which is increasing for various reasons. Although no definitive treatment has yet been identified for SCI, one possible treatment is adipose-derived stem cells(ADSCs). However, a key issue in transplantation is improving cells’ survival and function in the target tissue. Melatonin(MT) hormone with antioxidant properties can prolong cell survival and improve cell function. This study investigates the pre-conditioning of ADSCs with melatonin for enhancing the engraftment and neurological function of rats undergoing SCI.

Methods

42 male Sprague–Dawley rats were divided into six groups, including Control, Sham, Model, Vehicle, and Lesion treatments A and B. After acquiring white adipose tissue, stem cells were evaluated by flow cytometry. SCI was then applied in Model, Vehicle, A, and B groups. Group A and B received ADSCs and ADSCs + melatonin, respectively, 1 week after SCI, but the vehicle received only an intravenous injection for simulation; The other groups were recruited for the behavioral test. Immunohistochemistry(IHC) was used to assess the engraftment and differentiation of ADSCs in the SCI site. Basso, Beattie, and Bresnahan's score was used to evaluate motor function between the six groups.

Results

Histological studies and cell count confirmed ADSCs implantation at the injury site, which was higher in the MT-ADSCs (P < 0.001). IHC revealed the differentiation of ADSCs and MT-ADSCs into neurons, astrocytes, and oligodendrocyte lineage cells, which were higher in MT-ADSCs. Functional improvement was observed in SCI + ADSCs and SCI + MT-ADSCs groups.

Conclusion

The pre-conditioning of ADSCs with melatonin positively affects engraftment and neuronal differentiation in SCI but does not impact performance improvement compared to the ADSCs.

Different Sourced Extracellular Vesicles and Their Potential Applications in Clinical Treatments

Extracellular vesicles (EVs) include a heterogeneous group of natural cell-derived nanostructures that are increasingly regarded as promising biotherapeutic agents and drug delivery vehicles in human medicine. Desirable intrinsic properties of EVs including the ability to bypass natural membranous barriers and to deliver their unique biomolecular cargo to specific cell populations position them as fiercely competitive alternatives for currently available cell therapies and artificial drug delivery platforms. EVs with distinct characteristics can be released from various cell types into the extracellular environment as a means of transmitting bioactive components and altering the status of the target cell. Despite the existence of a large number of preclinical studies confirming the therapeutic efficacy of different originated EVs for treating several pathological conditions, in this review, we first provide a brief overview of EV biophysical properties with an emphasis on their intrinsic therapeutic benefits over cell-based therapies and synthetic delivery systems. Next, we describe in detail different EVs derived from distinct cell sources, compare their advantages and disadvantages, and recapitulate their therapeutic effects on various human disorders to highlight the progress made in harnessing EVs for clinical applications. Finally, knowledge gaps and concrete hurdles that currently hinder the clinical translation of EV therapies are debated with a futuristic perspective.

A multifunctional locus controls motor neuron differentiation through short and long noncoding RNAs

The transition from dividing progenitors to postmitotic motor neurons (MNs) is orchestrated by a series of events, which are mainly studied at the transcriptional level by analyzing the activity of specific programming transcription factors. Here, we identify a post‐transcriptional role of a MN‐specific transcriptional unit (MN2) harboring a lncRNA (lncMN2‐203) and two miRNAs (miR‐325‐3p and miR‐384‐5p) in this transition. Through the use of in vitro mESC differentiation and single‐cell sequencing of CRISPR/Cas9 mutants, we demonstrate that lncMN2‐203 affects MN differentiation by sponging miR‐466i‐5p and upregulating its targets, including several factors involved in neuronal differentiation and function. In parallel, miR‐325‐3p and miR‐384‐5p, co‐transcribed with lncMN2‐203, act by repressing proliferation‐related factors. These findings indicate the functional relevance of the MN2 locus and exemplify additional layers of specificity regulation in MN differentiation.

Xenogenic Neural Stem Cell-Derived Extracellular Nanovesicles Modulate Human Mesenchymal Stem Cell Fate and Reconstruct Metabolomic Structure

Extracellular nanovesicles, particularly exosomes, can deliver their diverse bioactive biomolecular content, including miRNAs, proteins, and lipids, thus providing a context for investigating the capability of exosomes to induce stem cells toward lineage-specific cells and tissue regeneration. In this study, it is demonstrated that rat subventricular zone neural stem cell-derived exosomes (rSVZ-NSCExo) can control neural-lineage specification of human mesenchymal stem cells (hMSCs). Microarray analysis shows that the miRNA content of rSVZ-NSCExo is a faithful representation of rSVZ tissue. Through immunocytochemistry, gene expression, and multi-omics analyses, the capability to use rSVZ-NSCExo to induce hMSCs into a neuroglial or neural stem cell phenotype and genotype in a temporal and dose-dependent manner via multiple signaling pathways is demonstrated. The current study presents a new and innovative strategy to modulate hMSCs fate by harnessing the molecular content of exosomes, thus suggesting future opportunities for rSVZ-NSCExo in nerve tissue regeneration.

Engineering Tissues of the Central Nervous System: Interfacing Conductive Biomaterials with Neural Stem/Progenitor Cells

Conductive biomaterials provide an important control for engineering neural tissues, where electrical stimulation can potentially direct neural stem/progenitor cell (NS/PC) maturation into functional neuronal networks. It is anticipated that stem cell-based therapies to repair damaged central nervous system (CNS) tissues and ex vivo, "tissue chip" models of the CNS and its pathologies will each benefit from the development of biocompatible, biodegradable, and conductive biomaterials. Here, technological advances in conductive biomaterials are reviewed over the past two decades that may facilitate the development of engineered tissues with integrated physiological and electrical functionalities. First, one briefly introduces NS/PCs of the CNS. Then, the significance of incorporating microenvironmental cues, to which NS/PCs are naturally programmed to respond, into biomaterial scaffolds is discussed with a focus on electrical cues. Next, practical design considerations for conductive biomaterials are discussed followed by a review of studies evaluating how conductive biomaterials can be engineered to control NS/PC behavior by mimicking specific functionalities in the CNS microenvironment. Finally, steps researchers can take to move NS/PC-interfacing, conductive materials closer to clinical translation are discussed.

The Therapeutic Potential of Exosomes in Soft Tissue Repair and Regeneration

Soft tissue defects are common following trauma and tumor extirpation. These injuries can result in poor functional recovery and lead to a diminished quality of life. The healing of skin and muscle is a complex process that, at present, leads to incomplete recovery and scarring. Regenerative medicine may offer the opportunity to improve the healing process and functional outcomes. Barriers to regenerative strategies have included cost, regulatory hurdles, and the need for cell-based therapies. In recent years, exosomes, or extracellular vesicles, have gained tremendous attention in the field of soft tissue repair and regeneration. These nanosized extracellular particles (30-140 nm) can break the cellular boundaries, as well as facilitate intracellular signal delivery in various regenerative physiologic and pathologic processes. Existing studies have established the potential of exosomes in regenerating tendons, skeletal muscles, and peripheral nerves through different mechanisms, including promoting myogenesis, increasing tenocyte differentiation and enhancing neurite outgrowth, and the proliferation of Schwann cells. These exosomes can be stored for immediate use in the operating room, and can be produced cost efficiently. In this article, we critically review the current advances of exosomes in soft tissue (tendons, skeletal muscles, and peripheral nerves) healing. Additionally, new directions for clinical applications in the future will be discussed.

Labelling stem cells with a nanoprobe for evaluating the homing behaviour in facial nerve injury repair

It is crucial and clinically relevant to clarify the homing efficiency and retention of stem cells in different implanting strategies of cell therapy for various injuries. However, the need for a tool for investigating the mechanisms is still unmet. We herein introduce multi-modal BaGdF₅:Yb,Tm nanoparticles as a nanoprobe to label adipose-derived stem cells (ADSCs) and detect the homing behavior with a micro-computed tomography (micro-CT) imaging technique. The migration of cells injected locally or intravenously, with or without a chemokine, CXCL 12, was compared. A higher homing efficiency of ADSCs was observed in both intravenously injected groups, in contrast to the low efficiency of cell retention in local implantation. Meanwhile, CXCL 12 promoted the homing of ADSCs, especially in the intravenous route. Nonetheless, the administration of CXCL 12 showed its therapeutic efficacy, whereas intravenous injection of ADSCs almost did not. Our work provided a tool for in vivo imaging of the behavior of implanted cells in preclinical studies of cell therapy, and more importantly, implied that the parameters for implanting stem cells in clinical operation should be carefully considered.

Extracellular vesicles and their role in peripheral nerve regeneration

Peripheral nerve injuries often result in sensory and motor dysfunction in respective parts of the body. Regeneration after peripheral nerve injuries is a complex process including the differentiation of Schwann cells, recruiting of macrophages, blood vessel growth and axonal regrowth. Extracellular vesicles (EVs) are considered to play a pivotal role in intercellular communication and transfer of biological information. Specifically, their bioactivity and ability to deliver cargos of various types of nucleic acids and proteins have made them a potential vehicle for neurotherapeutics. However, production, characterization, dosage and targeted delivery of EVs still pose challenges for the clinical translation of EV therapeutics. This review summarizes the current knowledge of EVs in the context of the healthy and injured peripheral nerve and addresses novel concepts for modification of EVs as therapeutic agents for peripheral nerve regeneration.

Distinct small non-coding RNA landscape in the axons and released extracellular vesicles of developing primary cortical neurons and the axoplasm of adult nerves

Neurons have highlighted the needs for decentralized gene expression and specific RNA function in somato-dendritic and axonal compartments, as well as in intercellular communication via extracellular vesicles (EVs). Despite advances in miRNA biology, the identity and regulatory capacity of other small non-coding RNAs (sncRNAs) in neuronal models and local subdomains has been largely unexplored.We identified a highly complex and differentially localized content of sncRNAs in axons and EVs during early neuronal development of cortical primary neurons and in adult axons in vivo. This content goes far beyond miRNAs and includes most known sncRNAs and precisely processed fragments from tRNAs, sno/snRNAs, Y RNAs and vtRNAs. Although miRNAs are the major sncRNA biotype in whole-cell samples, their relative abundance is significantly decreased in axons and neuronal EVs, where specific tRNA fragments (tRFs and tRHs/tiRNAs) mainly derived from tRNAs Gly-GCC, Val-CAC and Val-AAC predominate. Notably, although 5'-tRHs compose the great majority of tRNA-derived fragments observed in vitro, a shift to 3'-tRNAs is observed in mature axons in vivo.The existence of these complex sncRNA populations that are specific to distinct neuronal subdomains and selectively incorporated into EVs, equip neurons with key molecular tools for spatiotemporal functional control and cell-to-cell communication.

Challenges and opportunities in the study of extracellular vesicles: Global institutional context and national state of the art

In the last decade, the number of studies and publications on extracellular vesicles (EV) and exosomes has boomed. Colombia has displayed interest and progress in their study as shown in the increase of research project publications and products. However, this research field is still developing and has its own analytical challenges and technical limitations. For planning research projects and developing EV studies it is necessary to consider what is the state of the scientific field worldwide concerning EV nomenclature and classification, available techniques, resources, requirements and quality specifications, and the institutions that regulate the field. Answering this question will elicit EV studies that comply with international standards and respond to institutional demands and recommendations. However, the scientific information available is scattered and not all the aspects are considered in full. In this update, the available information is condensed and the official terms and currently defined nomenclature is presented, as well as the evolution of the field, the homogenization of the experimental parameters, the establishment of scientific authorities, institutions, and resources, and the recommendations generated worldwide for their development and research including their isolation, characterization, and functional studies. Finally, I analyzed the national context in a critical way, considering institutional strengths, common mistakes, and available analytical techniques and technologies.

An Overview of Mesenchymal Stem Cell-based Therapy Mediated by Noncoding RNAs in the Treatment of Neurodegenerative Diseases

Mesenchymal stem cells (MSCs) have become a promising tool for neurorestorative therapy of neurodegenerative diseases (NDDs), which are mainly characterized by the progressive and irreversible loss of neuronal structure and function in the central or peripheral nervous system. Recently, studies have reported that genetic manipulation mediated by noncoding RNAs (ncRNAs) can increase survival and neural regeneration of transplanted MSCs, offering a new strategy for clinical translation. In this review, we summarize the potential role and regulatory mechanism of two major types of ncRNAs, including microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), during the neurogenesis of MSCs with gene expression profile analyses. We also overview the realization of MSC-based therapy mediated by ncRNAs in the treatment of spinal cord injury, stroke, Alzheimer's disease and peripheral nerve injury. It is expected that ncRNAs will become promising therapeutic targets for NDD on stem cells, while the underlying mechanisms require further exploration.

Extracellular vesicles for tissue repair and regeneration: Evidence, challenges and opportunities

Extracellular vesicles (EVs) are biological nanoparticles naturally secreted by cells, acting as delivery vehicles for molecular messages. During the last decade, EVs have been assigned multiple functions that have established their potential as therapeutic mediators for a variety of diseases and conditions. In this review paper, we report on the potential of EVs in tissue repair and regeneration. The regenerative properties that have been associated with EVs are explored, detailing the molecular cargo they carry that is capable of mediating such effects, the signaling cascades triggered in target cells and the functional outcome achieved. EV interactions and biodistribution in vivo that influence their regenerative effects are also described, particularly upon administration in combination with biomaterials. Finally, we review the progress that has been made for the successful implementation of EV regenerative therapies in a clinical setting.

Protocol to Study the Role of Extracellular Vesicles During Induced Stem Cell Differentiation

Extracellular vesicles (EVs) are vesicles released by cells, which due to their cargo and cell membrane proteins induce changes in the recipient cells. These vesicles can be a novel option to induce stem cell differentiation. Here we described a method to induce mesenchymal stem cell differentiation (MSC) into neuron-like cells using small EVs from neurons. First, we will describe a method based on neurons to induce adipocyte derived stem cells differentiation, a type of MSC, by coculturing both using inserts. Secondly, we will describe a follow-up method by using only isolated neuron-derived small EVs to directly induce ADSC differentiation in neuron-like cells. Importantly, in both methods it is possible to avoid the direct cell-to-cell contact, thus allowing for the study of soluble factors role during stem cell differentiation.

Generation of neural progenitor cells from porcine-induced pluripotent stem cells

In this study, porcine embryonic fibroblasts (pEFs) were reprogrammed into porcine-induced pluripotent stem cells (piPSCs) using either human or mouse specific sequences for the OCT4, SOX2, c-Myc, and KLF4 transcription factors. In total, three pEFs lines were reprogrammed, cultured for at least 15 passages, and characterized regarding their pluripotency status (alkaline phosphatase expression, embryoid body formation, expression of exogenous and endogenous genes, and immunofluorescence). Two piPSC lines were further differentiated, using chemical inhibitors, into putative neural progenitor-like (NPC-like) cells with subsequent analyses of their morphology and expression of neural markers such as NESTIN and GFAP as well as immunofluorescent labeling of NESTIN, β-TUBULIN III, and VIMENTIN. NPC-like cells were positive for all the neural markers tested. These results evidence of the generation of porcine NPC-like cells after in vitro induction with chemical inhibitors, representing an adequate model for future regenerative and translational medicine research.

Mastering the Tools: Natural versus Artificial Vesicles in Nanomedicine

Naturally occurring extracellular vesicles and artificially made vesicles represent important tools in nanomedicine for the efficient delivery of biomolecules and drugs. Since its first appearance in the literature 50 years ago, the research on vesicles is progressing at a fast pace, with the main goal of developing carriers able to protect cargoes from degradation, as well as to deliver them in a time- and space-controlled fashion. While natural occurring vesicles have the advantage of being fully compatible with their host, artificial vesicles can be easily synthetized and functionalized according to the target to reach. Research is striving to merge the advantages of natural and artificial vesicles, in order to provide a new generation of highly performing vesicles, which would improve the therapeutic index of transported molecules. This progress report summarizes current manufacturing techniques used to produce both natural and artificial vesicles, exploring the promises and pitfalls of the different production processes. Finally, pros and cons of natural versus artificial vesicles are discussed and compared, with special regard toward the current applications of both kinds of vesicles in the healthcare field.

RPE Cells Engulf Microvesicles Secreted by Degenerating Rod Photoreceptors

Rhodopsin is mislocalized to the inner segment plasma membrane (IS PM) in various blinding disorders including autosomal-dominant retinitis pigmentosa caused by class I rhodopsin mutations. In these disorders, rhodopsin-laden microvesicles are secreted into the extracellular milieu by afflicted photoreceptor cells. Using a Xenopus laevis model expressing class I mutant rhodopsin or Na+/K+-ATPase (NKA) fused to Dendra2, we fluorescently labeled the microvesicles and found retinal pigment epithelial (RPE) cells are capable of engulfing microvesicles containing rhodopsin. A unique sorting mechanism allows class I mutant rhodopsin, but not NKA, to be packaged into the microvesicles. Under normal physiological conditions, NKA is not shed as microvesicles to the extracellular space, but is degraded intracellularly. Those studies provide novel insights into protein homeostasis in the photoreceptor IS PM.

Pharmacotherapy to gene editing: potential therapeutic approaches for Hutchinson-Gilford progeria syndrome

Hutchinson-Gilford progeria syndrome (HGPS), commonly called progeria, is an extremely rare disorder that affects only one child per four million births. It is characterized by accelerated aging in affected individuals leading to premature death at an average age of 14.5 years due to cardiovascular complications. The main cause of HGPS is a sporadic autosomal dominant point mutation in LMNA gene resulting in differently spliced lamin A protein known as progerin. Accumulation of progerin under nuclear lamina and activation of its downstream effectors cause perturbation in cellular morphology and physiology which leads to a systemic disorder that mainly impairs the cardiovascular system, bones, skin, and overall growth. Till now, no cure has been found for this catastrophic disorder; however, several therapeutic strategies are under development. The current review focuses on the overall progress in the field of therapeutic approaches for the management/cure of HGPS. We have also discussed the new disease models that have been developed for the study of this rare disorder. Moreover, we have highlighted the therapeutic application of extracellular vesicles derived from stem cells against aging and aging-related disorders and, therefore, suggest the same for the treatment of HGPS.

Epigallocatechin-3-gallate preconditioned Adipose-derived Stem Cells confer Neuroprotection in aging rat brain

Aging is the most important current issue and is usually accompanied by complications, such as cardiovascular disorders and neurodegenerative diseases, which are the leading causes of death worldwide and the second major cause of death in Taiwan. In this study, we have investigated the protective effect of adipose-derived mesenchymal stem cells (ADSCs) and the role of epigallocatechin gallate (EGCG) in enhancing this effect in aging cerebral cortex of rats. Further, we attempted to elucidate the molecular mechanism through which EGCG influences the protective effects of ADSC. ADSCs, co-cultured with EGCG, were injected into 20-month-old Wistar rats. Hematoxylin and eosin staining of the cerebral cortex revealed noticeable neurogenic activity and visible improvements in the integrity of the pre-frontal cortex tissue, compared to that in rats treated with ADSCs alone. Western blot analysis confirmed that ADSC, co-cultured with EGCG, enhanced cell survival via the p-Akt pathway and improved mitochondrial biogenesis via the SIRT-1 pathway. Moreover, it increased the available brain-derived neurotrophic factor to a higher degree than that in the ADSC group. Furthermore, western blotting showed that EGCG improved the antioxidant activity of the ADSCs in the cortex tissues via the Nrf-2 and HO-1 pathway. Based on these findings, we propose that this variation in stem cell treatment may facilitate functional recovery and enhanced neuroprotection in aged brains.