Mesenchymal Stem Cells from Wharton's Jelly and Amniotic Fluid

The discovery of mesenchymal stem cells (MSCs) in perinatal sources, such as the amniotic fluid (AF) and the umbilical connective tissue, the so-called Wharton's jelly (WJ), has transformed them into promising stem cell grafts for the application in regenerative medicine. The advantages of AF-MSCs and WJ-MSCs over adult MSCs, such as bone marrow-derived mesenchymal stem cells (BMMSCs), include their minimally invasive isolation procedure, their more primitive cell character without being tumourigenic, their low immunogenicity and their potential autologous application in congenital disorders and when cryopreserved in adulthood. This chapter gives an overview of the biology of AF-MSCs and WJMSCs, and their regenerative potential based on the results of recent preclinical and clinical studies. In the end, open questions concerning the use of WJ-MSCs and AF-MSCs in regenerative medicine will be emphasized

Mesenchymal stromal cells from umbilical cord Wharton's jelly trigger oligodendroglial differentiation in neural progenitor cells through cell-to-cell contact.

BACKGROUND AIMS Wharton's jelly mesenchymal stromal cells (WJ-MSCs) might be ideal candidates to treat perinatal brain damage. Their secretome has been shown to have beneficial effects on neuroregeneration, in part through interaction with neural progenitor cells (NPCs). However, it remains unclear whether cell-to-cell contact decisively contributes to this positive effect. The objective of this study was to elucidate the mechanism through which differentiation in NPCs is triggered after exposure to WJ-MSCs. Furthermore, given that WJ-MSCs can be derived from term (tWJ-MSCs) or preterm (ptWJ-MSCs) deliveries and that WJ-MSCs might be used for transplantations independent of gestational age, the influence of tWJ-MSCs versus ptWJ-MSCs on the differentiation capacities of NPCs was studied. METHODS The effect of tWJ-MSCs and ptWJ-MSCs on the expression of neuroglial markers in NPCs was assessed in co-culture (CC), conditioned medium (CM) or transwell CC experiments by immunocytochemistry, real-time polymerase chain reaction and Western blot. Additionally, mass spectrometry was used to study their secretomes. RESULTS NPCs showed an increased expression of glial markers after CC with WJ-MSCs or exposure to WJ-MSC-CMs. CC had a more prominent effect on the expression of glial markers compared with CM or transwell CCs. tWJ-MSCs more strongly induced the expression of mature oligodendroglial markers compared with ptWJ-MSCs. A possible role in enhancing this maturation could be attributed to the laminin α2-subunit. CONCLUSIONS Cell-to-cell contact between WJ-MSCs and NPCs induces oligodendrogenesis on NPCs, whereas trophic factor secretion is sufficient to promote astrogenesis. Thus, transplanting WJ-MSCs may promote endogenous neuroregeneration in perinatal brain damage

Intranasal Delivery of Umbilical Cord-Derived Mesenchymal Stem Cells Preserves Myelination in Perinatal Brain Damage.

Preterm white matter injury (WMI) is an important cause for long-term disability. Stem cell transplantation has been proposed as a novel therapeutic approach. However, intracerebral transplantation is not feasible for clinical purpose in newborns. Intranasal delivery of cells to the brain might be a promising, noninvasive therapeutic approach to restore the damaged brain. Therefore, our goal is to study the remyelinating potential of human Wharton's jelly mesenchymal stem cells (hWJ-MSCs) after intranasal delivery. Wistar rat pups, previously brain-damaged by a combined hypoxic-ischemic and inflammatory insult, received hWJ-MSC (150,000 cells in 3 μL) that were intranasally delivered twice to each nostril (600,000 cells total). WMI was assessed by immunohistochemistry and western blot for myelination, astrogliosis, and microgliosis. The expression of preoligodendrocyte markers, and neurotrophic factors, was analyzed by real-time polymerase chain reaction. Animals treated with intranasally delivered hWJ-MSC showed increased myelination and decreased gliosis compared to untreated animals. hWJ-MSC may, therefore, modulate the activation of microglia and astrocytes, resulting in a change of the brain microenvironment, which facilitates the maturation of oligodendrocyte lineage cells. This is the first study to show that intranasal delivery of hWJ-MSC in rats prevented hypomyelination and microgliosis in a model of WMI in the premature rat brain. Further studies should address the dose and frequency of administration

One Step Closer to Remyelination after Perinatal Brain Damage: Wharton’s Jelly Mesenchymal Stem Cell-Derived Exosomes Drive Neural Progenitors towards Oligodendroglial Cell Fate

INTRODUCTION: The loss of oligodendrocyte progenitor cells leading to overall hypomyelination of the brain is a major hallmark in perinatal brain damage. Experimental transplantations of mesenchymal stem cells (MSC) in animal models of perinatal brain damage strongly indicate that the regenerative effects rely on released factors such as MSC-derived exosomes. METHODS: Thus, the aim of this study is to investigate the capacity of exosomes from human Wharton’s jelly-derived MSC (WJ-MSC) to determine neural progenitor cells (NPC) towards oligodendroglial cell fate. WJ-MSC-derived exosomes were isolated from culture supernatants by serial high-speed and ultracentrifugations. Exosome microRNA (miRNA) content was assessed by real-time PCR. After 72 h of co-culture with WJ-MSC-derived EV, NPC were evaluated for the expression of markers involved in oligodendroglial specification and differentiation by real-time PCR. RESULTS: miRNA that are involved in oligodendroglial cell fate specification and differentiation (miR-338, miR-9, miR-19b, miR-138) were present in WJ-MSC-derived exosomes. The expression of miR-338-3p, known to trigger oligodendrocyte specification, was significantly increased in NPC after co-culture with exosomes. In addition, the gene expression of the transcription factor neurogenic differentiation factor 1 (Neurod1), which blocks oligodendrogenic specification and is repressed by miR-338, was significantly reduced in NPC after co-culture with exosomes. Furthermore, the gene expression of the transcription factor Hairy and enhancer of split (HES1) induced by the Notch signaling pathway, which is activated during oligodendroglial specification, was significantly elevated in NPC after incubation with exosomes. CONCLUSION: In conclusion, isolated WJ-MSC-derived exosomes expressed miRNA having key roles in oligodendrogenesis. Exosomes induced NPC towards oligodendroglial cell fate, ascribing a promising role in neuroregeneration to WJ-MSC-derived exosomes. Financial support by Gottfried and Julia Bangerter-Rhyner Foundatio

Anti-Inflammatory Effects of Exosomes Derived from Human Umbilical Cord Mesenchymal Stem Cells on Neuroglia

Wharton’s jelly mesenchymal stem cells (WJ-MSC) have the capacity to reduce neuroinflammation and induce tissue regeneration in perinatal brain damage despite of their low long-term survival in host tissue. The therapeutic function of WJ- MSC is mainly ascribed to their paracrine secretion involving the shedding of cell-derived exosomes. The aim of this study is to evaluate the anti-inflammatory effects of WJ-MSC-derived exosomes on neuroglia in vitro. WJ-MSC derived exosomes were isolated from cell culture supernatants using a protocol consisting of several steps of successive centrifugations and ultra-centrifugations. The isolated exosomes were characterized by their expression of endosomal markers and their size using a membrane-based antibody array and electron microscopy. In vitro models involving oxygen glucose deprivation and reoxygenation (OGD-R) and lipopolysaccharide (LPS) stimulation were used to test the anti-inflammatory effects of the exosomes on activated primary astrocytes and immortalized microglia cells. After the co-culture with WJ-MSC derived exosomes, glia cells were evaluated for their expression of activation markers and production of pro-inflammatory cytokines by real-time PCR, enzyme-linked immunosorbent assay (ELISA) and Western blot. WJ-MSC-derived exosomes were positive for endosomal markers, including TSG101 and ALIX, and had a mean diameter of 34 nm. In co-culturing experiments, WJ-MSC-derived exosomes prevented the upregulation of the astrocyte activation marker glial fibrillary acidic protein (Gfap) in response to 6h of OGD and 48h of reoxygenation. WJ-MSC-derived exosomes further tend to suppress the upregulation of pro-inflammatory cytokines such as interleukin 1 beta (IL-1b), tumor necrosis factor alpha (TNF-α) and inducible isoform of nitric oxide synthase (iNOS) in response to 24h LPS stimulation. In conclusion, we demonstrate that WJ-MSC-derived exosomes are potent modulators of neuroglia activation in hypoxia/ ischemia and inflammation. Hence not only WJ-MSC, but also WJ-MSC-derived exosomes are able to support tissue regeneration by reducing inflammation. As a result, WJ-MSC-derived exosomes might represent a novel cell-free approach to treat perinatal brain damage

The Potential Oligodendroglial Fate Specification Capacity of Exosomes Derived from Stem Cells of the Umbilical Cord Tissue

INTRODUCTION: The neuroregenerative effects of transplanted mesenchymal stem cells (MSC) in animal models of perinatal brain damage are presumed to rely on secreted factors including MSC-derived exosomes. Thus, the aim of this study is the evaluation of the oligodendroglial fate specification capacity of human Wharton’s jelly-derived MSC (WJ-MSC) on neural progenitor cells (NPC). METHODS: WJ-MSC-derived exosomes were isolated from culture supernatants by serial centrifugation, characterized by the expression of endosomal markers (membrane-based antibody array) and their size (electron microscopy). The exosomal microRNA (miRNA) content was assessed by real-time PCR. The exosomes were stained with the red fluorescent celltracker dye CM-DIL to analyze the potential interaction with NPC. Exosomal RNA was further fluorescently labeled to investigate its potential release into NPC. After the culture with exosomes, NPC were evaluated for the expression of proliferation and oligodendroglial differentiation markers by real-time PCR. RESULTS: WJ-MSC-derived exosomes were positive for endosomal markers, including TSG101 and ALIX, and had a mean diameter of 19 nm. The exosomes contained miRNAs that are involved in the differentiation of oligodendrocyte progenitor cells and in oligodendroglial fate determination (miR-338, miR-9, miR-19b, miR-138). Fluorescently labeled exosomal RNA was detected in NPC after co-culture. The gene expression of the transcription factor inhibitor of DNA binding protein (ID)2, which blocks oligodendrogenesis, was reduced in NPC post co-culture with exosomes. The transcription of ID4, which counteracts the function of ID2 was enhanced in NPC following incubation with exosomes. CONCLUSIONS: We successfully isolated WJ-MSC-derived exosomes. The exosomes contain miRNAs having decisive roles in oligodendroglial fate specification and differentiation, ascribing a potential neuroregenerative role to WJ-MSC-derived exosomes. Financial support by CryoSave Switzerland