The secretome of stem cells isolated from the adipose tissue and Wharton jelly acts differently on central nervous system derived cell populations

Secretome of Differentiated PC12 Cells Enhances Neuronal Differentiation in Human Mesenchymal Stem Cells Via NGF-Like Mechanism

The secretome-mediated responses over cellular physiology are well documented. Stem cells have been ruling the field of secretomics and its role in regenerative medicine since the past few years. However, the mechanistic aspects of secretome-mediated responses and the role of other cells in this area remain somewhat elusive. Here, we investigate the effects of secretome-enriched conditioned medium (CM) of neuronally differentiated PC12 cells on the neuronal differentiation of human mesenchymal stem cells (hMSCs). The exposure to CM at a ratio of 1:1 (CM: conditioned medium of PC12 cells) led to neuronal induction in hMSCs. This neuronal induction was compared with a parallel group of cells exposed to nerve growth factor (NGF). There was a marked increase in neurite length and expression of neuronal markers (β-III tubulin, neurofilament-M (NF-M), synaptophysin, NeuN in exposed hMSCs). Experimental group co-exposed to NGF and CM showed an additive response via MAPK signaling and directed the cells particularly towards cholinergic lineage. The ability of CM to enhance the neuronal properties of stem cells could aid in their rapid differentiation into neuronal subtypes in case of stem cell transplantation for neuronal injuries, thus broadening the scope of non-stem cell-based applications in the area of secretomics.

Co-Transplantation of Adipose Tissue-Derived Stromal Cells and Olfactory Ensheathing Cells for Spinal Cord Injury Repair

Patients suffering from spinal cord injury (SCI) still have a dismal prognosis. Despite all the efforts developed in this area, currently there are no effective treatments. Therefore, cell therapies have been proposed as a viable alternative to the current treatments used. Adipose tissue-derived stromal cells (ASCs) and olfactory ensheathing cells (OECs) have been used with promising results in different models of SCI, namely due to the regenerative properties of the secretome of the first, and the guidance capability of the second. Using an in vitro model of axonal growth, the dorsal root ganglia explants, we demonstrated that OECs induce neurite outgrowth mainly through cell-cell interactions, while ASCs' effects are strongly mediated by the release of paracrine factors. A proteomic analysis of ASCs' secretome revealed the presence of proteins involved in VEGF, PI3K, and Cadherin signaling pathways, which may be responsible for the effects observed. Then, the cotransplantation of ASCs and OECs showed to improve motor deficits of SCI-rats. Particular parameters of movement such as stepping, coordination, and toe clearance were improved in rats that received the transplant of cells, in comparison to nontreated rats. A histological analysis of the spinal cord tissues revealed that transplantation of ASCs and OECs had a major effect on the reduction of inflammatory cells close the lesion site. A slight reduction of astrogliosis was also evident. Overall, the results obtained with the present work indicate that the cotransplantation of ASCs and OECs brings important functional benefits to the injured spinal cord. Stem Cells 2018;36:696-708.

The neuroprotective effect of rat adipose tissue-derived mesenchymal stem cell-conditioned medium on cortical neurons using an in vitro model of SCI inflammation

Objectives In this study, a new approach was used with an in vitro model in which neural cells were exposed to conditioned media from the injured spinal cord (SCI-CM) mimicking a local inflammatory microenvironment . Subsequently, the neuroprotective effect of rat adipose tissue-derived msesenchymal stem cell-conditioned media (ATMSC-CM) was investigated through a cell-free based therapy, which was used to treat cortical neurons and astrocytes under inflammation. Methods Primary cell cultures isolated from postnatal day (P6) Wistar rat brain cortex were exposed to SCI-CM derived from the central lesion, rostral and caudal segments of injured spinal cord. After 48 h incubation, the SCI-CM was replaced and primary cultures were cultivated either in DMEM media alone or in ATMSC-CM for 72 h. The impact of ATMSC-CM on the viability of neurons and astrocytes was assessed using a CyQUANT® Direct Cell Proliferation Assay Kit as well as immunocytochemistry analysis. Results Immunocytochemical analysis revealed significant decrease in the number of MAP2 positive neurons exposed to SCI-CM compared to Control. Protection by ATMSC-CM was associated with increased survival of neurons compared to primary culture cultivated in DMEM media alone. The ATMSC-CM effect on astrocytes was more variable and without any significant impact. Conclusion The results demonstrate that SCI-CM mimicking inflammation can reduce cortical neuron survival, and subsequent exposure to ATMSC-CM can stabilize the neuronal population most likely via released neuroprotective and trophic factors. In addition, astrogliosis was not affected by ATMSC-CM.

Tips on How to Collect and Administer the Mesenchymal Stem Cell Secretome for Central Nervous System Applications

Human mesenchymal stem cells (hMSCs) have been proposed as possible therapeutic agents for central nervous system (CNS) disorders. Recently, it has been suggested that their effects are mostly mediated through their secretome, which contains a number of neuroregulatory molecules capable of increasing cell proliferation, differentiation, and survival in different physiological conditions. Here, we present an overview of the hMSC secretome as a possible candidate in the creation of new cell-free therapies, demonstrating the process of its collection and route of administration, focusing our attention on their effects in CNS regenerative medicine.

Adipose-derived stem cells decrease pain in a rat model of oxaliplatin-induced neuropathy: Role of VEGF-A modulation

Oxaliplatin therapy of colorectal cancer induces a dose-dependent neuropathic syndrome in 50% of patients. Pharmacological treatments may offer limited relief; scientific efforts are needed for new therapeutic approaches. Therefore we evaluated in a preclinical setting the pain relieving properties of mesenchymal stem cells and its secretome. Rat adipose stem cells (rASCs) were administered in a rat model of oxaliplatin-induced neuropathy. A single intravenous injection of rASCs reduced oxaliplatin-dependent mechanical hypersensitivity to noxious and non-noxious stimuli taking effect 1 h after administration, peaking 6 h thereafter and lasting 5 days. Cell-conditioned medium was ineffective. Repeated rASCs injections every 5 days relieved pain each time with a comparable effect. Labeled rASCs were detected in the bloodstream 1 and 3 h after administration and found in the liver 24 h thereafter. In oxaliplatin-treated rats, the plasma concentration of vascular endothelial growth factor (pan VEGF-A) was increased while the isoform VEGF₁₆₅b was upregulated in the spinal cord. Both alterations were reverted by rASCs. The anti-VEGF-A monoclonal antibody bevacizumab (intraperitoneally) reduced oxaliplatin-dependent pain. Studying the peripheral and central role of VEGF₁₆₅b in pain, we determined that the intraplantar and intrathecal injection of the growth factor induced a pro-algesic effect. In the oxaliplatin neuropathy model, the intrathecal infusion of bevacizumab, anti-rat VEGF₁₆₅b antibody and rASCs reduced pain. Adult adipose mesenchymal stem cells could represent a novel approach in the treatment of neuropathic pain. The regulation of VEGF-A is suggested as an effective mechanism in the complex response orchestrated by stem cells against neuropathy.

Sonic hedgehog (SHH) signaling improves the angiogenic potential of Wharton's jelly-derived mesenchymal stem cells (WJ-MSC)

Background

Wharton’s jelly-derived mesenchymal stem cells (WJ-MSC) show remarkable therapeutic potential to repair tissue upon injury via paracrine signaling by secreting diverse trophic factors that promote angiogenesis. However, the mechanisms and signaling pathways that regulate the induction of these specific factors are still mostly unknown. Emerging evidence suggests that Sonic hedgehog (SHH) plays a central role in angiogenesis and tissue maintenance. However, its contribution to the angiogenic potential of MSC has not been fully addressed. The aim of this work was to characterize the expression of the SHH pathway components in WJ-MSC primary cultures and to evaluate their angiogenic responsiveness to SHH signaling.

Methods

Primary cell cultures obtained from human umbilical cords were treated with pharmacological modulators of the SHH pathway. We evaluated the modulation of diverse trophic factors in cell lysates, conditioned medium, and functional in vitro assays. In addition, we determined the angiogenic potential of the SHH pathway in the chicken chorioallantoic membrane, an in vivo model.

Results

Our results show that WJ-MSC express components of the canonical SHH pathway and are activated by its signaling. In fact, we provide evidence of basal autocrine/paracrine SHH signaling in WJ-MSC. SHH pathway stimulation promotes the secretion of angiogenic factors such as activin A, angiogenin, angiopoietin 1, granulocyte-macrophage colony-stimulating factor, matrix metallometallopeptidase -9, and urokinase-type plasminogen activator, enhancing the pro-angiogenic capabilities of WJ-MSC both in vitro and in vivo.

Conclusion

WJ-MSC are a cell population responsive to SHH pathway stimulation. Basal SHH signaling is in part responsible for the angiogenic inductive properties of WJ-MSC. Overall, exogenous activation of the SHH pathway enhances the angiogenic properties of WJ-MSC, making this cell population an ideal target for treating tissue injury.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-017-0653-8) contains supplementary material, which is available to authorized users.

Effects of a defined xeno-free medium on the growth and neurotrophic and angiogenic properties of human adult stem cells

BACKGROUND

The growth properties and neurotrophic and angiogenic effects of human mesenchymal stromal cells (MSCs) cultured in a defined xeno-free, serum-free medium (MesenCult-XF) were investigated.

METHODS

Human MSCs from adipose tissue (ASCs) and bone marrow (BMSCs) were cultured in Minimum Essential Medium-alpha (α-MEM) containing fetal calf serum or in MesenCult-XF. Proliferation was measured over 10 passages and the colony-forming unit (CFU) assay and expression of cluster of differentiation (CD) surface markers were determined. Neurite outgrowth and angiogenic activity of the MSCs were determined.

RESULTS

At early passage, both ASCs and BMSCs showed better proliferation in MesenCult-XF compared with standard α-MEM-containing serum. However, CFUs were significantly lower in MesenCult-XF. ASCs cultured in MesenCult-XF continued to expand at faster rates than cells grown in serum. BMSCs showed morphological changes at late passage in MesenCult-XF and stained positive for senescence β-galactosidase activity. Expression levels of CD73 and CD90 were similar in both cell types under the various culture conditions but CD105 was significantly reduced at passage 10 in MesenCult-XF. In vitro stimulation of the cells enhanced the expression of brain-derived neurotrophic factor (BDNF), vascular endothelial growth factor (VEGF-A) and angiopoietin-1. Stimulated ASCs grown in MesenCult-XF evoked the longest neurite outgrowth in a neuron co-culture model. Stimulated BMSCs grown in MesenCult-XF produced the most extensive network of capillary-like tube structures in an in vitro angiogenesis assay.

CONCLUSIONS

ASCs and BMSCs exhibit high levels of neurotrophic and angiogenic activity when grown in the defined serum-free medium indicating their suitability for treatment of various neurological conditions. However, long-term expansion in MesenCult-XF might be restricted to ASCs.

Cytokine, Chemokine, and Growth Factor Profile Characterization of Undifferentiated and Osteoinduced Human Adipose-Derived Stem Cells

Bone is the second most manipulated tissue after blood. Adipose-derived stem cells (ASCs) may become a convenient source of MSC for bone regenerative protocols. Surprisingly, little is known about the most significant biomolecules these cells produce and release after being osteoinduced. Therefore, the present study aimed at dosing 13 candidates chosen among the most representative cytokines, chemokines, and growth factors within the conditioned media of osteodifferentiated and undifferentiated ASCs. Two acknowledged osteoblastic cell models, that is, MG-63 and SaOs-2 cells, were compared. Notably, IL-6, IL-8, MCP-1, and VEGF were highly produced and detectable in ASCs. In addition, while IL-6 and IL-8 seemed to be significantly induced by the osteogenic medium, no such effect was seen for MCP-1 and VEGF. Overall SaOS-2 had a poor expression profile, which may be consistent with the more differentiated phenotype of SaOs-2 compared to ASCs and MG-63. Instead, in maintaining medium, MG-63 displayed a very rich production of IL-12, MCP-1, IP-10, and VEGF, which were significantly reduced in osteogenic conditions, with the only exception of MCP-1. The high expression of MCP-1 and VEGF, even after the osteogenic commitment, may support the usage of ASCs in bone regenerative protocols by recruiting both osteoblasts and osteoclasts of the host.

Mesenchymal stem/stromal cells-a key mediator for regeneration after perinatal morbidity?

Perinatal complications in both term- and preterm-born infants are a leading cause of neonatal morbidities and mortality. Infants face different challenges in the neonatal intensive care unit with long-term morbidities such as perinatal brain injury and bronchopulmonary dysplasia being particularly devastating. While advances in perinatal medicine have improved our understanding of the pathogenesis, effective therapies to prevent and/or reduce the severity of these disorders are still lacking. The potential of mesenchymal stem/stromal cell (MSC) therapy has emerged during the last two decades, and an increasing effort is conducted to address brain- and lung-related morbidities in neonates at risk. Various studies support the notion that MSCs have protective effects. MSCs are an easy source and may be readily available after birth in a clinical setting. MSCs' mechanisms of action are diverse, including migration and homing, release of growth factors and immunomodulation, and the potential to replace injured cells. Here, we review the pathophysiology of perinatally acquired brain and lung injuries and focus on MSCs as potential candidates for therapeutic strategies summarizing preclinical and clinical evidence.

Therapeutic potential of adipose stem cell-derived conditioned medium against pulmonary hypertension and lung fibrosis

BACKGROUND AND PURPOSE

Pulmonary hypertension (PH) and pulmonary fibrosis (PF) are life threatening cardiopulmonary diseases. Existing pharmacological interventions have failed to improve clinical outcomes or reduce disease-associated mortality. Emerging evidence suggests that stem cells offer an effective treatment approach against various pathological conditions. It has been proposed that their beneficial actions may be mediated via secretion of paracrine factors. Herein, we evaluated the therapeutic potential of conditioned media (CM) from adipose stem cells (ASCs) against experimental models of PH and PF.

EXPERIMENTAL APPROACH

Monocrotaline (MCT) or bleomycin (Bleo) was injected into male Sprague-Dawley rats to induce PH or PF respectively. A subset of MCT and Bleo animals were treated with ASCs or CM. Echocardiographic and haemodynamic measurements were performed at the end of the study. Lung and heart tissues were harvested for RNA, protein and histological measurements.

KEY RESULTS

CM treatment attenuated MCT-induced PH by improving pulmonary blood flow and inhibiting cardiac remodelling. Further, histological studies revealed that right ventricular fibrosis, pulmonary vessel wall thickness and pericyte distribution were significantly decreased by CM administration. Likewise, CM therapy arrested the progression of PF in the Bleo model by reducing collagen deposition. Elevated expression of markers associated with tissue remodelling and inflammation were significantly reduced in both PF and PH lungs. Similar results were obtained with ASCs administration.

CONCLUSIONS AND IMPLICATIONS

Our study indicates that CM treatment is as effective as ASCs in treating PH and PF. These beneficial effects of CM may provide an innovative approach to treat cardiopulmonary disorders.

Bioactive molecules derived from umbilical cord mesenchymal stem cells

Umbilical cord mesenchymal stem cells (UCMSCs) retain their intrinsic stem cell potential while at the same time displaying high proliferation rates, powerful differentiation capacity, and low immunogenicity. They can also secrete multiple bioactive molecules that exert specific physiological functions. Thus, UCMSCs represent excellent candidates for cell therapy in regenerative medicine and tissue engineering. Abundant preclinical research on different disease models has shown that UCMSCs can accelerate wound or nerve damage recovery and suppress tumor progression. In fact, UCMSCs are thought to possess a higher therapeutic potential than MSCs derived from other tissues. Increasing evidence suggests that the mechanism underlying UCSMCs efficacy depends mostly on cell secretions, in contrast to the early paradigm of cell replacement and differentiation. In this review, we discuss UCMSCs biological characteristics, their secretome-based therapeutic mechanism, and potential applications.

MSCs-Derived Exosomes: Cell-Secreted Nanovesicles with Regenerative Potential

Exosomes are membrane-enclosed nanovesicles (30–150 nm) that shuttle active cargoes between different cells. These tiny extracellular vesicles have been recently isolated from mesenchymal stem cells (MSCs) conditioned medium, a population of multipotent cells identified in several adult tissues. MSCs paracrine activity has been already shown to be the key mediator of their elicited regenerative effects. On the other hand, the individual contribution of MSCs-derived exosomes for these effects is only now being unraveled. The administration of MSCs-derived exosomes has been demonstrated to restore tissue function in multiple diseases/injury models and to induce beneficial in vitro effects, mainly mediated by exosomal-enclosed miRNAs. Additionally, the source and the culture conditions of MSCs have been shown to influence the regenerative responses induced by exosomes. Therefore, these studies reveal that MSCs-derived exosomes hold a great potential for cell-free therapies that are safer and easier to manipulate than cell-based products. Nevertheless, this is an emerging research field and hence, further studies are required to understand the full dimension of this complex intercellular communication system and how it can be optimized to take full advantage of its therapeutic effects. In this mini-review, we summarize the most significant new advances in the regenerative properties of MSCs-derived exosomes and discuss the molecular mechanisms underlying these effects.

Combination of a peptide-modified gellan gum hydrogel with cell therapy in a lumbar spinal cord injury animal model

Spinal Cord Injury (SCI) is a highly incapacitating condition for which there is still no cure. Current clinical approaches are mainly based on palliative care, so there is a need to find possible treatments to SCI. Cellular transplantation is regarded with great expectation due to the therapeutic potential of cells such as Adipose tissue-derived Stromal/Stem Cells (ASCs) or Olfactory Ensheathing Cells (OECs). Both are accessible sources and present positive paracrine and cell-to-cell interactions, previously reported by our group. Additionally, biomaterials such as hydrogels have been applied in SCI repair with promising results. We propose to combine a GRGDS-modified gellan gum hydrogel with ASCs and OECs in order to promote SCI regeneration. In vitro, ASCs and OECs could be co-cultured within GG-GRGDS hydrogels inducing a more robust neurite outgrowth when compared to controls. In vivo experiments in a hemisection SCI rat model revealed that the administration of ASCs and OECs encapsulated in a GG-GRGDS hydrogel led to significant motor improvements when compared to both control (SCI) and hydrogel alone (GG-GRGDS) groups. This was accompanied by a decreased infiltration of inflammatory cells and astrocytes, and by an increased intensity of neurofilament. These results suggest evident gains induced by the encapsulation of ASCs and OECs in GG-GRGDS based hydrogels.

Transcriptional profiling reveals intrinsic mRNA alterations in multipotent mesenchymal stromal cells isolated from bone marrow of newly-diagnosed type 1 diabetes patients

Background

Bone marrow multipotent mesenchymal stromal cells (MSCs) are a diverse subset of precursors that contribute to the homeostasis of the hematopoietic niche. MSCs can be isolated and expanded in vitro and have unique immunomodulatory and regenerative properties that make them attractive for the treatment of autoimmune diseases, including type 1 diabetes (T1D). Whether autologous or allogeneic MSCs are more suitable for therapeutic purposes has not yet been established. While autologous MSCs may present abnormal function, allogeneic cells may be recognized and rejected by the host immune system. Thus, studies that investigate biological characteristics of MSCs isolated from T1D patients are essential to guide future clinical applications.

Methods

Bone marrow-derived MSCs from recently diagnosed type 1 diabetes patients (T1D-MSCs) were compared with those from healthy individuals (C-MSCs) for morphological and immunophenotypic characteristics and for differentiation potential. Bioinformatics approaches allowed us to match absolute and differential gene expression of several adhesion molecules, immune mediators, growth factors, and their receptors involved with hematopoietic support and immunomodulatory properties of MSCs. Finally, the differentially expressed genes were collated for functional pathway enrichment analysis.

Results

T1D-MSCs and C-MSCs were similar for morphology, immunophenotype, and differentiation potential. Our absolute gene expression results supported previous literature reports, while also detecting new potential molecules related to bone marrow-derived MSC functions. T1D-MSCs showed intrinsic abnormalities in mRNA expression, including the immunomodulatory molecules VCAM-1, CXCL12, HGF, and CCL2. Pathway analyses revealed activation of sympathetic nervous system and JAK STAT signaling in T1D-MSCs.

Conclusions

Collectively, our results indicate that MSCs isolated from T1D patients present intrinsic transcriptional alterations that may affect their therapeutic potential. However, the implications of these abnormalities in T1D development as well as in the therapeutic efficacy of autologous MSCs require further investigation.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-016-0351-y) contains supplementary material, which is available to authorized users.

Unveiling the Differences of Secretome of Human Bone Marrow Mesenchymal Stem Cells, Adipose Tissue-Derived Stem Cells, and Human Umbilical Cord Perivascular Cells: A Proteomic Analysis

The use of human mesenchymal stem cells (hMSCs) has emerged as a possible therapeutic strategy for CNS-related conditions. Research in the last decade strongly suggests that MSC-mediated benefits are closely related with their secretome. Studies published in recent years have shown that the secretome of hMSCs isolated from different tissue sources may present significant variation. With this in mind, the present work performed a comparative proteomic-based analysis through mass spectrometry on the secretome of hMSCs derived from bone marrow (BMSCs), adipose tissue (ASCs), and human umbilical cord perivascular cells (HUCPVCs). The results revealed that BMSCs, ASCs, and HUCPVCs differed in their secretion of neurotrophic, neurogenic, axon guidance, axon growth, and neurodifferentiative proteins, as well as proteins with neuroprotective actions against oxidative stress, apoptosis, and excitotoxicity, which have been shown to be involved in several CNS disorder/injury processes. Although important changes were observed within the secretome of the cell populations that were analyzed, all cell populations shared the capability of secreting important neuroregulatory molecules. The difference in their secretion pattern may indicate that their secretome is specific to a condition of the CNS. Nevertheless, the confirmation that the secretome of MSCs isolated from different tissue sources is rich in neuroregulatory molecules represents an important asset not only for the development of future neuroregenerative strategies but also for their use as a therapeutic option for human clinical trials.

In vivo immunomodulatory effects of adipose-derived mesenchymal stem cells conditioned medium in experimental autoimmune encephalomyelitis

Mesenchymal stem cells (MSCs) are well known to possess neuroprotective and immunomodulatory effects, due to cell-to-cell interaction and their soluble factors. We conducted a comparative analysis of the immunomodulatory properties of adipose tissue mesenchymal stem cells (AT-MSCs) and their conditioned media (CM), derived from C57/BL6 mice, for mitigating the adverse clinical course of experimental autoimmune encephalomyelitis (EAE). We measure IL4, IL17 and IFNɣ production of supernatant from spleen cells. We analyzed brain cell infiltration, splenocyte proliferation and evaluated the percentage of CD4+CD25+FOXP3+splenic cell population in all EAE C57/BL6 mice. AT-MSCs and its conditioned medium induced CD4+CD25+FOXP3+regulatory T cells after in vitro co-culture with naïve T cells. There is no significant difference in the clinical scores and body weight of EAE mice treated with AT-MSCs and CM. The reduction in proliferative responses and brain cell infiltration was more pronounced in mice injected with CM than other groups. It is found that the percentage of splenic CD4+CD25+FOXP3+ population as well as the level of IL4 production in mice administrated with AT-MSCs is increased compared to other animals. Our results suggest that AT-MSCs-derived CM is promising in stem cell therapy, due to their neuroprotective and immunomudulatory properties.

Secretome of mesenchymal progenitors from the umbilical cord acts as modulator of neural/glial proliferation and differentiation

It was recently shown that the conditioned media (CM) of Human Umbilical Cord Perivascular Cells (HUCPVCs), a mesenchymal progenitor population residing within the Wharton Jelly of the umbilical cord, was able to modulate in vitro the survival and viability of different neuronal and glial cells populations. In the present work, we aimed to assess if the secretome of HUCPVCs is able to 1) induce the differentiation of human telencephalon neural precursor cells (htNPCs) in vitro, and 2) modulate neural/glial proliferation, differentiation and survival in the dentate gyrus (DG) of adult rat hippocampus. For this purpose, two separate experimental setups were performed: 1) htNPCs were incubated with HUCPVCs-CM for 5 days after which neuronal differentiation was assessed and, 2) HUCPVCs, or their respective CM, were injected into the DG of young adult rats and their effects assessed 7 days later. Results revealed that the secretome of HUCPVCs was able to increase neuronal cell differentiation in vitro; indeed, higher densities of immature (DCX(+) cells) and mature neurons (MAP-2(+) cells) were observed when htNPCs were incubated with the HUCPVCs-CM. Additionally, when HUCPVCs and their CM were injected in the DG, results revealed that both cells or CM were able to increase the endogenous proliferation (BrdU(+) cells) 7 days after injection. It was also possible to observe an increased number of newborn neurons (DCX(+) cells), upon injection of HUCPVCs or their respective CM. Finally western blot analysis revealed that after CM or HUCPVCs transplantation, there was an increase of fibroblast growth factor-2 (FGF-2) and, to a lesser extent, of nerve growth factor (NGF) in the DG tissue. Concluding, our results have shown that the transplantation of HUCPVCs or the administration of their secretome were able to potentiate neuronal survival and differentiation in vitro and in vivo.

Neuromuscular Regeneration: Perspective on the Application of Mesenchymal Stem Cells and Their Secretion Products

Mesenchymal stem cells are posing as a promising character in the most recent therapeutic strategies and, since their discovery, extensive knowledge on their features and functions has been gained. In recent years, innovative sources have been disclosed in alternative to the bone marrow, conveying their associated ethical concerns and ease of harvest, such as the umbilical cord tissue and the dental pulp. These are also amenable of cryopreservation and thawing for desired purposes, in benefit of the donor itself or other patients in pressing need. These sources present promising possibilities in becoming useful cell sources for therapeutic applications in the forthcoming years. Effective and potential applications of these cellular-based strategies for the regeneration of peripheral nerve are overviewed, documenting recent advances and identified issues for this research area in the near future. Finally, besides the differentiation capacities attributed to mesenchymal stem cells, advances in the recognition of their effective mode of action in the regenerative theatre have led to a new area of interest: the mesenchymal stem cells' secretome. The paracrine modulatory pathway appears to be a major mechanism by which these are beneficial to nerve regeneration and comprehension on the specific growth factors, cytokine, and extracellular molecules secretion profiles is therefore of great interest.

The conditioned medium from osteo-differentiating human mesenchymal stem cells affects the viability of triple negative MDA-MB231 breast cancer cells

This study aimed to investigate the effect of conditioned media (CM) from osteo-differentiating and adipo-differentiating human mesenchymal stem cells (MSCs) isolated from lipoaspirates of healthy female donors on the viability of triple-negative breast cancer cells MDA-MB231. The CM of undifferentiated and differentiating MSCs were collected after 7, 14, 21 and 28 days of culture. The effects of MSC CM on cell proliferation were assessed using an 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay after 24 h. The effects of osteo-differentiating cell CM on apoptotic promotion, cell cycle impairment, mitochondrial transmembrane potential dissipation, production of reactive oxygen species and autophagosome accumulation were analysed by flow cytometry and Western blot. MTT assay showed that only CM collected from osteo-induced cells at day 28 (d28O-CM) reduced tumour cell viability. Treatment with d28O-CM restrained cell cycle progression through G2 phase, elicited a caspase-8-driven apoptotic effect already after 5 h of culture, and down-regulated autophagosome accumulation and beclin-1 expression. The finding that factor(s) secreted by osteo-differentiating MSCs shows properties of an apoptotic inducer and autophagy inhibitor on triple-negative breast cancer cells may have an important applicative potential that deserves further investigation.

Endogenous recovery after brain damage: molecular mechanisms that balance neuronal life/death fate

Neuronal survival depends on multiple factors that comprise a well-fueled energy metabolism, trophic input, clearance of toxic substances, appropriate redox environment, integrity of blood-brain barrier, suppression of programmed cell death pathways and cell cycle arrest. Disturbances of brain homeostasis lead to acute or chronic alterations that might ultimately cause neuronal death with consequent impairment of neurological function. Although we understand most of these processes well when they occur independently from one another, we still lack a clear grasp of the concerted cellular and molecular mechanisms activated upon neuronal damage that intervene in protecting damaged neurons from death. In this review, we summarize a handful of endogenously activated mechanisms that balance molecular cues so as to determine whether neurons recover from injury or die. We center our discussion on mechanisms that have been identified to participate in stroke, although we consider different scenarios of chronic neurodegeneration as well. We discuss two central processes that are involved in endogenous repair and that, when not regulated, could lead to tissue damage, namely, trophic support and neuroinflammation. We emphasize the need to construct integrated models of neuronal degeneration and survival that, in the end, converge in neuronal fate after injury. Under neurodegenerative conditions, endogenously activated mechanisms balance out molecular cues that determine whether neurons contend toxicity or die. Many processes involved in endogenous repair may as well lead to tissue damage depending on the strength of stimuli. Signaling mediated by trophic factors and neuroinflammation are examples of these processes as they regulate different mechanisms that mediate neuronal demise including necrosis, apoptosis, necroptosis, pyroptosis and autophagy. In this review, we discuss recent findings on balanced regulation and their involvement in neuronal death.

Do hypoxia/normoxia culturing conditions change the neuroregulatory profile of Wharton Jelly mesenchymal stem cell secretome?

Introduction

The use of human umbilical cord Wharton Jelly-derived mesenchymal stem cells (hWJ-MSCs) has been considered a new potential source for future safe applications in regenerative medicine. Indeed, the application of hWJ-MSCs into different animal models of disease, including those from the central nervous system, has shown remarkable therapeutic benefits mostly associated with their secretome. Conventionally, hWJ-MSCs are cultured and characterized under normoxic conditions (21 % oxygen tension), although the oxygen levels within tissues are typically much lower (hypoxic) than these standard culture conditions. Therefore, oxygen tension represents an important environmental factor that may affect the performance of mesenchymal stem cells in vivo. However, the impact of hypoxic conditions on distinct mesenchymal stem cell characteristics, such as the secretome, still remains unclear.

Methods

In the present study, we have examined the effects of normoxic (21 % O₂) and hypoxic (5 % O₂) conditions on the hWJ-MSC secretome. Subsequently, we address the impact of the distinct secretome in the neuronal cell survival and differentiation of human neural progenitor cells.

Results

The present data indicate that the hWJ-MSC secretome collected from normoxic and hypoxic conditions displayed similar effects in supporting neuronal differentiation of human neural progenitor cells in vitro. However, proteomic analysis revealed that the use of hypoxic preconditioning led to the upregulation of several proteins within the hWJ-MSC secretome.

Conclusions

Our results suggest that the optimization of parameters such as hypoxia may lead to the development of strategies that enhance the therapeutic effects of the secretome for future regenerative medicine studies and applications.

Mesenchymal stem cells secretome as a modulator of the neurogenic niche: basic insights and therapeutic opportunities

Neural stem cells (NSCs) and mesenchymal stem cells (MSCs) share few characteristics apart from self-renewal and multipotency. In fact, the neurogenic and osteogenic stem cell niches derive from two distinct embryonary structures; while the later originates from the mesoderm, as all the connective tissues do, the first derives from the ectoderm. Therefore, it is highly unlikely that stem cells isolated from one niche could form terminally differentiated cells from the other. Additionally, these two niches are associated to tissues/systems (e.g., bone and central nervous system) that have markedly different needs and display diverse functions within the human body. Nevertheless they do share common features. For instance, the differentiation of both NSCs and MSCs is intimately associated with the bone morphogenetic protein family. Moreover, both NSCs and MSCs secrete a panel of common growth factors, such as nerve growth factor (NGF), glial derived neurotrophic factor (GDNF), and brain derived neurotrophic factor (BDNF), among others. But it is not the features they share but the interaction between them that seem most important, and worth exploring; namely, it has already been shown that there are mutually beneficially effects when these cell types are co-cultured in vitro. In fact the use of MSCs, and their secretome, become a strong candidate to be used as a therapeutic tool for CNS applications, namely by triggering the endogenous proliferation and differentiation of neural progenitors, among other mechanisms. Quite interestingly it was recently revealed that MSCs could be found in the human brain, in the vicinity of capillaries. In the present review we highlight how MSCs and NSCs in the neurogenic niches interact. Furthermore, we propose directions on this field and explore the future therapeutic possibilities that may arise from the combination/interaction of MSCs and NSCs.

Hydrogels and Cell Based Therapies in Spinal Cord Injury Regeneration

Spinal cord injury (SCI) is a central nervous system- (CNS-) related disorder for which there is yet no successful treatment. Within the past several years, cell-based therapies have been explored for SCI repair, including the use of pluripotent human stem cells, and a number of adult-derived stem and mature cells such as mesenchymal stem cells, olfactory ensheathing cells, and Schwann cells. Although promising, cell transplantation is often overturned by the poor cell survival in the treatment of spinal cord injuries. Alternatively, the therapeutic role of different cells has been used in tissue engineering approaches by engrafting cells with biomaterials. The latter have the advantages of physically mimicking the CNS tissue, while promoting a more permissive environment for cell survival, growth, and differentiation. The roles of both cell- and biomaterial-based therapies as single therapeutic approaches for SCI repair will be discussed in this review. Moreover, as the multifactorial inhibitory environment of a SCI suggests that combinatorial approaches would be more effective, the importance of using biomaterials as cell carriers will be herein highlighted, as well as the recent advances and achievements of these promising tools for neural tissue regeneration.

Systems biology approach to developing S2RM-based “systems therapeutics” and naturally induced pluripotent stem cells

The degree to, and the mechanisms through, which stem cells are able to build, maintain, and heal the body have only recently begun to be understood. Much of the stem cell’s power resides in the release of a multitude of molecules, called stem cell released molecules (SRM). A fundamentally new type of therapeutic, namely “systems therapeutic”, can be realized by reverse engineering the mechanisms of the SRM processes. Recent data demonstrates that the composition of the SRM is different for each type of stem cell, as well as for different states of each cell type. Although systems biology has been successfully used to analyze multiple pathways, the approach is often used to develop a small molecule interacting at only one pathway in the system. A new model is emerging in biology where systems biology is used to develop a new technology acting at multiple pathways called “systems therapeutics”. A natural set of healing pathways in the human that uses SRM is instructive and of practical use in developing systems therapeutics. Endogenous SRM processes in the human body use a combination of SRM from two or more stem cell types, designated as S²RM, doing so under various state dependent conditions for each cell type. Here we describe our approach in using state-dependent SRM from two or more stem cell types, S²RM technology, to develop a new class of therapeutics called “systems therapeutics.” Given the ubiquitous and powerful nature of innate S²RM-based healing in the human body, this “systems therapeutic” approach using S²RM technology will be important for the development of anti-cancer therapeutics, antimicrobials, wound care products and procedures, and a number of other therapeutics for many indications.

Adipose-derived stem cells for nerve repair: hype or reality?

Peripheral nerve injury is a relatively commonly occurring trauma which seriously compromises the quality of life for many individuals. There is a major need to devise new treatment strategies, and one possible approach is to develop cellular therapies to bioengineer new nerve tissue and/or modulate the endogenous regenerative mechanisms within the peripheral nervous system. In this short review we describe how stem cells isolated from adipose tissue could be a suitable element of this approach. We describe the possible mechanisms through which the stem cells might exert a positive influence on peripheral nerve regeneration. These include their ability to differentiate into cells resembling Schwann cells and their secretion of a plethora of neurotrophic growth factors. We also review the literature describing the effects of these cells when tested using in vivo peripheral nerve injury models.

The Secretome of Bone Marrow and Wharton Jelly Derived Mesenchymal Stem Cells Induces Differentiation and Neurite Outgrowth in SH-SY5Y Cells

The goal of this study was to determine and compare the effects of the secretome of mesenchymal stem cells (MSCs) isolated from human bone-marrow (BMSCs) and the Wharton jelly surrounding the vein and arteries of the umbilical cord (human umbilical cord perivascular cells (HUCPVCs)) on the survival and differentiation of a human neuroblastoma cell line (SH-SY5Y). For this purpose, SH-SY5Y cells were differentiated with conditioned media (CM) from the MSCs populations referred above. Retinoic acid cultured cells were used as control for neuronal differentiated SH-SY5Y cells. SH-SY5Y cells viability assessment revealed that the secretome of BMSCs and HUCPVCs, in the form of CM, was able to induce their survival. Moreover, immunocytochemical experiments showed that CM from both MSCs was capable of inducing neuronal differentiation of SH-SY5Y cells. Finally, neurite lengths assessment and quantitative real-time reverse-transcription polymerase chain reaction (RT-PCR) analysis demonstrated that CM from BMSCs and HUCPVCs differently induced neurite outgrowth and mRNA levels of neuronal markers exhibited by SH-SY5Y cells. Overall, our results show that the secretome of both BMSCs and HUCPVCs was capable of supporting SH-SY5Y cells survival and promoting their differentiation towards a neuronal phenotype.

Umbilical cord mesenchymal stem cells: the new gold standard for mesenchymal stem cell-based therapies?

Due to their self-renewal capacity, multilineage differentiation potential, paracrine effects, and immunosuppressive properties, mesenchymal stromal cells (MSCs) are an attractive and promising tool for regenerative medicine. MSCs can be isolated from various tissues but despite their common immunophenotypic characteristics and functional properties, source-dependent differences in MSCs properties have recently emerged and lead to different clinical applications. Considered for a long time as a medical waste, umbilical cord appears these days as a promising source of MSCs. Several reports have shown that umbilical cord-derived MSCs are more primitive, proliferative, and immunosuppressive than their adult counterparts. In this review, we aim at synthesizing the differences between umbilical cord MSCs and MSCs from other sources (bone marrow, adipose tissue, periodontal ligament, dental pulp,…) with regard to their proliferation capacity, proteic and transcriptomic profiles, and their secretome involved in their regenerative, homing, and immunomodulatory capacities. Although umbilical cord MSCs are until now not particularly used as an MSC source in clinical practice, accumulating evidence shows that they may have a therapeutic advantage to treat several diseases, especially autoimmune and neurodegenerative diseases.

Intravenous transplants of human adipose-derived stem cell protect the brain from traumatic brain injury-induced neurodegeneration and motor and cognitive impairments: cell graft biodistribution and soluble factors in young and aged rats

Traumatic brain injury (TBI) survivors exhibit motor and cognitive symptoms from the primary injury that can become aggravated over time because of secondary cell death. In the present in vivo study, we examined the beneficial effects of human adipose-derived stem cells (hADSCs) in a controlled cortical impact model of mild TBI using young (6 months) and aged (20 months) F344 rats. Animals were transplanted intravenously with 4 × 10(6) hADSCs (Tx), conditioned media (CM), or vehicle (unconditioned media) at 3 h after TBI. Significant amelioration of motor and cognitive functions was revealed in young, but not aged, Tx and CM groups. Fluorescent imaging in vivo and ex vivo revealed 1,1' dioactadecyl-3-3-3',3'-tetramethylindotricarbocyanine iodide-labeled hADSCs in peripheral organs and brain after TBI. Spatiotemporal deposition of hADSCs differed between young and aged rats, most notably reduced migration to the aged spleen. Significant reduction in cortical damage and hippocampal cell loss was observed in both Tx and CM groups in young rats, whereas less neuroprotection was detected in the aged rats and mainly in the Tx group but not the CM group. CM harvested from hADSCs with silencing of either NEAT1 (nuclear enriched abundant transcript 1) or MALAT1 (metastasis associated lung adenocarcinoma transcript 1), long noncoding RNAs (lncRNAs) known to play a role in gene expression, lost the efficacy in our model. Altogether, hADSCs are promising therapeutic cells for TBI, and lncRNAs in the secretome is an important mechanism of cell therapy. Furthermore, hADSCs showed reduced efficacy in aged rats, which may in part result from decreased homing of the cells to the spleen.

Histological experimental study on the effect of stem cell therapy on adriamycin induced chemobrain

BACKGROUND AND OBJECTIVES

Negative consequences of chemotherapy on brain function were suggested and were addressed in animal models as the clinical phenomenon of chemobrain .It was postulated that adriamycin (ADR) induce changes in behaviour and in brain morphology. Human umbilical cord mesenchymal stem cells (HUCMSCs) could be induced to differentiate into neuron-like cells .The present study aimed at investigating the possible therapeutic effect of HUCMSC therapy on adriamycin induced chemobrain in rat.

METHODS AND RESULTS

Twenty five female albino rats were divided into control group, ADR group where rats were given single intraperitoneal (IP) injection of 5 mg/kg ADR. The rats were sacrificed two and four weeks following confirmation of brain damage. In stem cell therapy group, rats were injected with HUCMSCs following confirmation of brain damage and sacrificed two and four weeks after therapy. Brain sections were exposed to histological, histochemical, immunohistochemical and morphometric studies. In ADR group, multiple shrunken neurons exhibiting dark nuclei and surrounded by vacuoles were seen .In response to SC therapy ,multiple normal pyramidal nerve cells were noted. The area of shrunken nerve cells exhibiting dark nuclei, Prussion blue and CD105 positive cells were significantly different in ADR group in comparison to SC therapy group.

CONCLUSIONS

ADR induced progressive duration dependant cerebral degenerative changes. These changes were ameliorated following cord blood human mesenchymal stem cell therapy. A reciprocal relation was recorded between the extent of regeneration and the existence of undifferentiated mesenchymal stem cells.

The Regenerative Role of the Fetal and Adult Stem Cell Secretome

For a long time, the stem cell regenerative paradigm has been based on the assumption that progenitor cells play a critical role in tissue repair by means of their plasticity and differentiation potential. However, recent works suggest that the mechanism underlying the benefits of stem cell transplantation might relate to a paracrine modulatory effect rather than the replacement of affected cells at the site of injury. Therefore, mounting evidence that stem cells may act as a reservoir of trophic signals released to modulate the surrounding tissue has led to a paradigm shift in regenerative medicine. Attention has been shifted from analysis of the stem cell genome to understanding the stem cell “secretome”, which is represented by the growth factors, cytokines and chemokines produced through paracrine secretion. Insights into paracrine-mediated repair support a new approach in regenerative medicine and the isolation and administration of specific stem cell-derived paracrine factors may represent an extremely promising strategy, introducing paracrine-based therapy as a novel and feasible clinical application. In this review, we will discuss the regenerative potential of fetal and adult stem cells, with particular attention to their secretome.

A 3D in vitro model reveals differences in the astrocyte response elicited by potential stem cell therapies for CNS injury

AIM

This study aimed to develop a 3D culture model to test the extent to which transplanted stem cells modulate astrocyte reactivity, where exacerbated glial cell activation could be detrimental to CNS repair success.

MATERIALS & METHODS

The reactivity of rat astrocytes to bone marrow mesenchymal stem cells, neural crest stem cells (NCSCs) and differentiated adipose-derived stem cells was assessed after 5 days. Schwann cells were used as a positive control.

RESULTS

NCSCs and differentiated Schwann cell-like adipose-derived stem cells did not increase astrocyte reactivity. Highly reactive responses to bone marrow mesenchymal stem cells and Schwann cells were equivalent.

CONCLUSION

This approach can screen therapeutic cells prior to in vivo testing, allowing cells likely to trigger a substantial astrocyte response to be identified at an early stage. NCSCs and differentiated Schwann cell-like adipose-derived stem cells may be useful in treating CNS damage without increasing astrogliosis.

An Update on Translating Stem Cell Therapy for Stroke from Bench to Bedside

With a constellation of stem cell sources available, researchers hope to utilize their potential for cellular repair as a therapeutic target for disease. However, many lab-to-clinic translational considerations must be given in determining their efficacy, variables such as the host response, effects on native tissue, and potential for generating tumors. This review will discuss the current knowledge of stem cell research in neurological disease, mainly stroke, with a focus on the benefits, limitations, and clinical potential.

Mesenchymal stem cells secretome: a new paradigm for central nervous system regeneration?

The low regeneration potential of the central nervous system (CNS) represents a challenge for the development of new therapeutic strategies. Mesenchymal stem cells (MSCs) have been proposed as a possible therapeutic tool for CNS disorders. In addition to their differentiation potential, it is well accepted nowadays that their beneficial actions can also be mediated by their secretome. Indeed, it was already demonstrated, both in vitro and in vivo, that MSCs are able to secrete a broad range of neuroregulatory factors that promote an increase in neurogenesis, inhibition of apoptosis and glial scar formation, immunomodulation, angiogenesis, neuronal and glial cell survival, as well as relevant neuroprotective actions on different pathophysiological contexts. Considering their protective action in lesioned sites, MSCs' secretome might also improve the integration of local progenitor cells in neuroregeneration processes, opening a door for their future use as therapeutical strategies in human clinical trials. Thus, in this review we analyze the current understanding of MSCs secretome as a new paradigm for the treatment of CNS neurodegenerative diseases.

Mesenchymal stem cell therapy in lung disorders: pathogenesis of lung diseases and mechanism of action of mesenchymal stem cell

Lung disorders such as asthma, acute respiratory distress syndrome (ARDS), chronic obstructive lung disease (COPD), and interstitial lung disease (ILD) show a few common threads of pathogenic mechanisms: inflammation, aberrant immune activity, infection, and fibrosis. Currently no modes of effective treatment are available for ILD or emphysema. Being anti-inflammatory, immunomodulatory, and regenerative in nature, the administration of mesenchymal stem cells (MSCs) has shown the capacity to control immune dysfunction and inflammation in the lung. The intravenous infusion of MSCs, the common mode of delivery, is followed by their entrapment in lung vasculature before MSCs reach to other organ systems thus indicating the feasible and promising approach of MSCs therapy for lung diseases. In this review, we discuss the mechanistic basis for MSCs therapy for asthma, ARDS, COPD, and ILD.

Mesenchymal stem cells from human umbilical cord express preferentially secreted factors related to neuroprotection, neurogenesis, and angiogenesis

Mesenchymal stem cells (MSCs) are promising tools for the treatment of diseases such as infarcted myocardia and strokes because of their ability to promote endogenous angiogenesis and neurogenesis via a variety of secreted factors. MSCs found in the Wharton’s jelly of the human umbilical cord are easily obtained and are capable of transplantation without rejection. We isolated MSCs from Wharton’s jelly and bone marrow (WJ-MSCs and BM-MSCs, respectively) and compared their secretomes. It was found that WJ-MSCs expressed more genes, especially secreted factors, involved in angiogenesis and neurogenesis. Functional validation showed that WJ-MSCs induced better neural differentiation and neural cell migration via a paracrine mechanism. Moreover, WJ-MSCs afforded better neuroprotection efficacy because they preferentially enhanced neuronal growth and reduced cell apoptotic death of primary cortical cells in an oxygen-glucose deprivation (OGD) culture model that mimics the acute ischemic stroke situation in humans. In terms of angiogenesis, WJ-MSCs induced better microvasculature formation and cell migration on co-cultured endothelial cells. Our results suggest that WJ-MSC, because of a unique secretome, is a better MSC source to promote in vivo neurorestoration and endothelium repair. This study provides a basis for the development of cell-based therapy and carrying out of follow-up mechanistic studies related to MSC biology.

The secretome of alginate-encapsulated limbal epithelial stem cells modulates corneal epithelial cell proliferation

Limbal epithelial stem cells may ameliorate limbal stem cell deficiency through secretion of therapeutic proteins, delivered to the cornea in a controlled manner using hydrogels. In the present study the secretome of alginate-encapsulated limbal epithelial stem cells is investigated. Conditioned medium was generated from limbal epithelial stem cells encapsulated in 1.2% (w/v) calcium alginate gels. Conditioned medium proteins separated by 1-D gel electrophoresis were visualized by silver staining. Proteins of interest including secreted protein acidic and rich in cysteine, profilin-1, and galectin-1 were identified by immunoblotting. The effect of conditioned medium (from alginate-encapsulated limbal epithelial stem cells) on corneal epithelial cell proliferation was quantified and shown to significantly inhibit (P≤0.05) their growth. As secreted protein acidic and rich in cysteine was previously reported to attenuate proliferation of epithelial cells, this protein may be responsible, at least in part, for inhibition of corneal epithelial cell proliferation. We conclude that limbal epithelial stem cells encapsulated in alginate gels may regulate corneal epithelialisation through secretion of inhibitory proteins.

Proteomic techniques for characterisation of mesenchymal stem cell secretome

Mesenchymal stem cells (MSCs) are multipotent cells with a substantial potential in human regenerative medicine due to their ability to migrate to sites of injury, capability to suppress immune response and accessibility in large amount from patient's own bone marrow or fat tissue. It has been increasingly observed that the transplanted MSCs did not necessarily engraft and differentiate at the site of injury but might exert their therapeutic effects through secreted trophic signals. The MSCs secrete a variety of autocrine/paracrine factors, called secretome, that support regenerative processes in the damaged tissue, induce angiogenesis, protect cells from apoptotic cell death and modulate immune system. The cell culture medium conditioned by MSCs or osteogenic, chondrogenic as well as adipogenic precursors derived from MSCs has become a subject of intensive proteomic profiling in the search for and identification of released factors and microvesicles that might be applicable in regenerative medicine. Jointly with the methods for MSC isolation, expansion and differentiation, proteomic analysis of MSC secretome was enabled recently mainly due to the extensive development in protein separation techniques, mass spectrometry, immunological methods and bioinformatics. This review describes proteomic techniques currently applied or prospectively applicable in MSC secretomics, with a particular focus on preparation of the secretome sample, protein/peptide separation, mass spectrometry and protein quantification techniques, analysis of posttranslational modifications, immunological techniques, isolation and characterisation of secreted vesicles and exosomes, analysis of cytokine-encoding mRNAs and bioinformatics.

Unveiling the effects of the secretome of mesenchymal progenitors from the umbilical cord in different neuronal cell populations

It has been previously shown that the secretome of Human Umbilical Cord Perivascular Cells (HUCPVCs), known for their mesenchymal like stem cell character, is able to increase the metabolic viability and hippocampal neuronal cell densities. However, due to the different micro-environments of the distinct brain regions it is important to study if neurons isolated from different areas have similar, or opposite, reactions when in the presence of HUCPVCs secretome (in the form of conditioned media-CM). In this work we: 1) studied how cortical and cerebellar neuronal primary cultures behaved when incubated with HUCPVCs CM and 2) characterized the differences between CM collected at two different conditioning time points. Primary cultures of cerebellar and cortical neurons were incubated with HUCPVCs CM (obtained 24 and 96 h after three days of culturing). HUCPVCs CM had a higher impact on the metabolic viability and proliferation of cortical cultures, than the cerebellar ones. Regarding neuronal cell densities it was observed that with 24 h CM condition there were higher number MAP-2 positive cells, a marker for fully differentiated neurons; this was, once again, more evident in cortical cultures. In an attempt to characterize the differences between the two conditioning time points a proteomics approach was followed, based on 2D Gel analysis followed by the identification of selected spots by tandem mass spectrometry. Results revealed important differences in proteins that have been previously related with phenomena such as neurl cell viability, proliferation and differentiation, namely 14-3-3, UCHL1, hsp70 and peroxiredoxin-6. In summary, we demonstrated differences on how neurons isolated from different brain regions react to HUCPVCs secretome and we have identified different proteins (14-3-3 and hsp70) in HUCPVCs CM that may explain the above-referred results.

The stem cell secretome and its role in brain repair

Compelling evidence exists that non-haematopoietic stem cells, including mesenchymal (MSCs) and neural/progenitor stem cells (NPCs), exert a substantial beneficial and therapeutic effect after transplantation in experimental central nervous system (CNS) disease models through the secretion of immune modulatory or neurotrophic paracrine factors. This paracrine hypothesis has inspired an alternative outlook on the use of stem cells in regenerative neurology. In this paradigm, significant repair of the injured brain may be achieved by injecting the biologics secreted by stem cells (secretome), rather than implanting stem cells themselves for direct cell replacement. The stem cell secretome (SCS) includes cytokines, chemokines and growth factors, and has gained increasing attention in recent years because of its multiple implications for the repair, restoration or regeneration of injured tissues. Thanks to recent improvements in SCS profiling and manipulation, investigators are now inspired to harness the SCS as a novel alternative therapeutic option that might ensure more efficient outcomes than current stem cell-based therapies for CNS repair. This review discusses the most recent identification of MSC- and NPC-secreted factors, including those that are trafficked within extracellular membrane vesicles (EVs), and reflects on their potential effects on brain repair. It also examines some of the most convincing advances in molecular profiling that have enabled mapping of the SCS.

Combining adult stem cells and olfactory ensheathing cells: the secretome effect

Adipose-derived adult stem cells (ASCs), bone marrow mesenchymal stem cells (bmMSCs), and human umbilical cord perivascular cells (HUCPVCs) tissue have been widely tested for regenerative applications, such as bone regeneration. Moreover, olfactory ensheathing cells (OECs) show promise in promoting spinal cord injury (SCI) regeneration. Our group recently proposed the use of a hybrid scaffold targeting both vertebral bone repair and SCI regeneration. According to this concept, both MSCs and OECs should be in close contact to be influenced by the factors that are involved in secretion. For this reason, here we studied the effects of the OEC secretome on the metabolic activity and proliferation of ASCs, bmMSCs, and HUCPVCs. The stem cells' secretome effects on metabolic activity and proliferation of the OECs were also considered. In co-cultures of OECs with ASCs, bmMSCs, or HUCPVCs, the metabolic activity/viability, proliferation, and total cell numbers were measured after 2 and 7 days of culture. The results demonstrated that the secretome of OECs has a positive effect on the metabolic activity and proliferation of MSCs from different origins, especially on ASCs. Furthermore, in general, the stem cells' secretome also had a positive effect on the OECs behavior, particularly when ASCs were in co-culture with OECs. These results suggest that the most suitable combination of cells to be used in our hybrid scaffold is the OECs with the ASCs. Finally, this work adds new knowledge to the cell therapy field, bringing new information about paracrine interactions between OECs and distinct mesenchymal stems.