The antioxidant trolox inhibits aging and enhances prostaglandin E-2 secretion in mesenchymal stem cells

Mesenchymal stem cells (MSCs) have been widely used in regenerative medicine and clinical therapy due to their capabilities of proliferation, differentiation, and immune regulation. However, during in vitro expansion, MSCs are prone to aging, which largely limits their application. Prostaglandin E-2 (PGE-2) is a key effector secreted by MSCs to exert immunomodulatory effects. By screening the compound library for PGE-2 secretion, the antioxidant trolox was verified as a stimulator of MSCs to secrete PGE-2. The effect of antioxidant trolox on biological characteristics of MSCS, including aging, proliferation, and gene expression, was examined. The results demonstrated that trolox can resist aging, promote proliferation, and enhance PGE-2 secretion of MSCs without affecting their surface marker expression. Furthermore, trolox treatment up-regulates miR-17-92 clusters in MSCs and may contribute to its anti-aging effects. Thus, trolox addition might be beneficial for MSCs expansion and their application.     

Role of GM3 ganglioside in the pathology of some progressive human diseases and prognostic importance of serum anti-GM3 antibodies

Glycosphingolipids (gangliosides) have been characterized as important biological molecules with a key role as regulators in many physiological processes on cellular, tissue, organ, and organism levels. The deviations in their normal amounts, production, and metabolism are very often related to the development of many multi-factor socially important diseases. GM3 ganglioside, as a small molecule, plays important roles in the cascade regulatory pathways in the pathology of many disorders like neurodegenerative diseases, autoimmune diseases, inflammation, diabetes, malignant transformation, and others. Ganglioside GM3 and its derivatives are membrane-bound glycosphingolipids composed of an oligosaccharide head structure containing one sialic acid residue. These molecules transduce signals involved in cell surface events, including the phosphorylation of transmembrane receptors. This ganglioside is the most widely distributed among tissues, and it serves as a precursor for most of the more complex ganglioside species. GM3 inhibits the function of fibroblast growth factor receptor, and cell growth is regulated by GM3-enriched microdomain. GM3 is thought to inhibit immunologic functions, such as the proliferation and production of cytokines by T cells. On the other hand, the anti-ganglioside antibodies (AGAs) are important in many acquired demyelinating immunemediated neuropathies, like Multiple sclerosis (MS), Guillain–Barré syndrome (GBS) and its variation, Miller–Fisher syndrome (MFS) and could be suggested as important diagnostic and prognostic markers about the describe diseases and their etiology. We show that the complexes of anti-ganglioside antibodies to GM3 (detected by ELISA) may be useful diagnostic and prognostic tool markers for autoimmune diseases, neurodegenerative disorders, malignancy, diabetes, and inflammation. Our pilot studies suggest increased serum IgG anti-GM3 antibodies titers in patients with secondary progressive MS (SPMS), throat cancer, elder people with diabetes (89–96 years), old Lewis rats (30–33 months), and in the serum of subjected on lead intoxication BALB/c mice treated by salinomycin. We observed no changes in the titers in healthy elder people (89–96 years), in 70-year-old woman on dialysis, in relapsing-remitting MS (RRMS) patients on long-term treatment with Glatiramer acetate, Laquinimod, and Interferons, as well as in 18– 22 months old Wistar rats and subjected on lead intoxication BALB/c mice treated by monensin and dimercaptosuccinic acid (DMSA). Considerable decrease of serum GM3 in early MS correlate with early damage and severe destruction of the blood–brain barrier, which provides impetus to initiate early therapy.     

Glycoproteomics in neurodegenerative diseases

Protein glycosylation regulates protein function and cellular distribution. Additionally, aberrant protein glycosylations have been recognized to play major roles in human disorders, including neurodegenerative diseases. Glycoproteomics, a branch of proteomics that catalogs and quantifies glycoproteins, provides a powerful means to systematically profile the glycopeptides or glycoproteins of a complex mixture that are highly enriched in body fluids, and therefore, carry great potential to be diagnostic and/or prognostic markers. Application of this mass spectrometry‐based technology to the study of neurodegenerative disorders (e.g., Alzheimer's disease and Parkinson's disease) is relatively new, and is expected to provide insight into the biochemical pathogenesis of neurodegeneration, as well as biomarker discovery. In this review, we have summarized the current understanding of glycoproteins in biology and neurodegenerative disease, and have discussed existing proteomic technologies that are utilized to characterize glycoproteins. Some of the ongoing studies, where glycoproteins isolated from cerebrospinal fluid and human brain are being characterized in Parkinson's disease at different stages versus controls, are presented, along with future applications of targeted validation of brain specific glycoproteins in body fluids. © 2009 Wiley Periodicals, Inc., Mass Spec Rev 29:79–125, 2010     

Mesenchymal stem cells,the secretome and biomaterials: Regenerative medicine application

Mesenchymal stem cells (MSCs) are multipotent cells usually isolated from bone marrow, endometrium, adipose tissues, skin, and dental pulp. MSCs played a crucial role in regenerative therapy and have been introduced as an interdisciplinary field between cell biology and material science. Recently, MSCs have been widely explored for their application in regenerative medicine and COVID-19 treatment. Different approaches to evaluate the future of biomaterials and stem cell properties have been developed. However, misconceptions and ethical issues still exist, such as MSCs being non-angiogenic, anti-apoptotic, and immunoregulatory competencies. Embryonic stem cells isolation primarily requires the consent of donors and can include the killing of fertilized eggs. These issues generate questions related to ethical and moral issues. However, MSCs have gained considerable attention for tissue regeneration owing to their differentiation ability with immunomodulatory effects. They are capable of secreting a broad range of biomolecules such as proteins, nucleic acids, exosomes, microRNAs, and membrane vesicles, collectively known as secretomes. Secretomes are released in response to the surrounding microenvironment. In this article, we briefly address topics related to the therapeutic potential of MSCs as an advanced approach in the field of regenerative medicine and various perspectives.     

AAV-based gene therapy approaches for genetic forms of tauopathies and related neurogenetic disorders

Tauopathies comprise a spectrum of genetic and sporadic neurodegenerative diseases mainly characterized by the presence of hyperphosphorylated TAU protein aggregations in neurons or glia. Gene therapy, in particular adeno-associated virus (AAV)-based, is an effective medical approach for difficult-to-treat genetic diseases for which there are no convincing traditional therapies, such as tauopathies. Employing AAV-based gene therapy to treat, in particular, genetic tauopathies has many potential therapeutic benefits, but also drawbacks which need to be addressed in order to successfully and efficiently adapt this still unconventional therapy for the various types of tauopathies. In this Viewpoint, we briefly introduce some potentially treatable tauopathies, classify them according to their etiology, and discuss the potential advantages and possible problems of AAV-based gene therapy. Finally, we outline a future vision for the application of this promising therapeutic approach for genetic and sporadic tauopathies.     

Microenvironmental regulation of stem cells injected in the area at risk of neurodegenerative diseases

The complex mechanism of degenerative diseases and the non-specific modulation of regenerative targets are topics that need to be elucidated in order to advance the use of stem cells in improvement of neurodegenerative diseases. From pre-transplantation through post-transplantation, there are many changes in the conditions, both inside and outside of the stem cells that have not been carefully considered. This has hindered development in the field of cell therapy and regeneration. This viewpoint highlights the potential implications of intracellular and extracellular alterations of stem cells in transplanted areas at risk of neurodegenerative disease.     

Therapeutic application of mesenchymal stem cells-derived extracellular vesicles in colorectal cancer

Colorectal cancer (CRC) is the third most common cancer and the leading cause of cancer death globally. Resistance to therapy is a challenge for CRC treatment. Mesenchymal stem cells (MSCs) have become one of the furthermost effective approaches for tumor treatment due to their specific feature; however, their therapeutic function is controversial. Recently, extracellular vesicles (EVs) derived from MSCs (MSCs-EVs) have attracted extensive research attention due to their promising role in CRC treatment. EVs are cell-derived vesicles that transfer different biomolecules between cells, contributing to intracellular communication. MSCs-EVs can suppress CRC by delivering therapeutic agents to tumor cells. Several studies indicate that MSCs-EVs can serve as a drug delivery system for the treatment of different cancers. Various methods are used to modify (engineer) MSCs-EVs for loading therapeutic agents. Modified MSCs-EVs have improved specificity, targeting ability, and immunogenicity compared to synthetic carriers. Furthermore, CRC-EVs participate in regulating different cells, such as immune cells, fibroblasts, and endothelial cells, promoting tumorigenesis. MSCs-EVs-based therapy indicates a high potential in the treatment of cancer; however, the majority of studies have been conducted in the pre-clinical, and their clinical applications need further scrutiny. In this review, we describe the biogenesis of EVs, focusing on the effect of MSCs-EVs on CRC cells and CRC-derived EVs on other cells. Furthermore, MSCs-EVs as a drug delivery system for cancers is also reviewed, and perspectives regarding the therapeutic application of MSCs-EVs are discussed.     

Proteomics of brain extracellular fluid (ECF) and cerebrospinal fluid (CSF)

Mass spectrometry has become the gold standard for the identification of proteins in proteomics. In this review, I will discuss the available literature on proteomic experiments that analyze human cerebrospinal fluid (CSF) and brain extracellular fluid (ECF), mostly obtained by cerebral microdialysis. Both materials are of high diagnostic value in clinical neurology, for example, in cerebrovascular disorders like stroke, neurodegenerative diseases like Alzheimer's Disease, Parkinson's Disease, amyotrophic lateral sclerosis (ALS), traumatic brain injury and cerebral infectious and inflammatory disease, such as multiple sclerosis. Moreover, there are standard procedures for sampling. In a number of studies in recent years, biomarkers have been proposed in CSF and ECF for improved diagnosis or to control therapy, based on proteomics and mass spectrometry. I will also discuss the needs for a transition of research‐based experimental screening with mass spectrometry to fast and reliable diagnostic instrumentation for clinical use. © 2008 Wiley Periodicals, Inc., Mass Spec Rev 29:17–28, 2010     

Proteomics in neurosciences

This review provides an outline of the most important proteomic applications in the study of neurodegenerative disorders including Alzheimer's (AD), Parkinson's (PD), Huntington's (HD), and prion diseases, and also discusses advances in cancer and addiction. One of the scopes is to illustrate the potential of proteomics in the biomarkers discovery of these diseases. Finally, this article comments the advantages and drawbacks of the most commonly used techniques and methods for samples preparation.     

The versatility of mesenchymal stem cells: From regenerative medicine to COVID,what is next?

Mesenchymal stem cells (MSCs) play key roles in regenerative medicine by promoting tissue healing. MSCs can be isolated from different adult tissues and they are able to differentiate into several lineages. Due to their anti-inflammatory, angiogenic and immune-modulatory properties, MSCs are suitable for tissue engineering applications and, when associated with biomaterials, their benefits can be improved. Moreover, recently, MSCs have been studied for new clinical applications, such as in the treatment of patients with COVID-19. MSCs regenerative potential has been attributed to their secretome, which comprises extracellular matrix, soluble proteins and several elements, including the release of extracellular vesicles. Even though, in order to explore all their therapeutic potential, it is still necessary to advance in the investigation of their basic cell biology characteristics.     

Mesenchymal stem cells derived secretome as an innovative cell-free therapeutic approach

The paracrine and immunomodulatory cytokines secreted by mesenchymal stem cells (MSCs), generally referred to as the MSCs derived secretome, has substantial potential for the treatment of many chronic and degenerative diseases. MSCs secretome contains both common and disease specific cytokines and modulators that can be beneficial against a wide range of chronic diseases. Herein, we discuss the MSCs secretome composition profile and its translational applicability and the challenges surrounding its use in clinical settings.     

S100B in brain damage and neurodegeneration

S100B is a calcium-binding peptide produced mainly by astrocytes that exert paracrine and autocrine effects on neurons and glia. Some knowledge has been acquired from in vitro and in vivo animal experiments to understand S100B's roles in cellular energy metabolism, cytoskeleton modification, cell proliferation, and differentiation. Also, insights have been gained regarding the interaction between S100B and the cerebral immune system, and the regulation of S100B activity through serotonergic transmission. Secreted glial S100B exerts trophic or toxic effects depending on its concentration. At nanomolar concentrations, S100B stimulates neurite outgrowth and enhances survival of neurons during development. In contrast, micromolar levels of extracellular S100B in vitro stimulate the expression of proinflammatory cytokines and induce apoptosis. In animal studies, changes in the cerebral concentration of S100B cause behavioral disturbances and cognitive deficits. In humans, increased S100B has been detected with various clinical conditions. Brain trauma and ischemia is associated with increased S100B concentrations, probably due to the destruction of astrocytes. In neurodegenerative, inflammatory and psychiatric diseases, increased S100B levels may be caused by secreted S100B or release from damaged astrocytes. This review summarizes published findings on S100B regarding human brain damage and neurodegeneration. Findings from in vitro and in vivo animal experiments relevant for human neurodegenerative diseases and brain damage are reviewed together with the results of studies on traumatic, ischemic, and inflammatory brain damage as well as neurodegenerative and psychiatric disorders. Methodological problems are discussed and perspectives for future research are outlined.     

Controversies in therapeutic application of mesenchymal stem cell-derived secretome

Though mesenchymal stem cells (MSCs) are considered as an important pillar of regenerative medicine, their regenerative potential has been shown to be limited in several pathological conditions. The adverse properties of MSC-based cell therapy have drawn attention to the therapeutic use of MSC-derived secretome. However, MSC-originated exosomes and microvesicles can also possess a significant impact on disease development, including cancer. By interchanging secretome, MSCs can interact with tumor cells and promote mutual exchange/induction of cellular markers. In addition, enzymes secreted into and activated within exosomes can result in the acquisition of new tumor cell properties. Therefore, therapeutic applications of MSC-derived secretome require much caution.     

Mesenchymal stem cells-derived extracellular vesicles as ‘natural’ drug delivery system for tissue regeneration

Mesenchymal stem cells (MSCs) have abilities to mediate tissue protection through mechanisms of anti-apoptosis, anti-oxidative stress and anti-fibrosis as well as tissue regeneration through mechanisms of cell proliferation, differentiation and angiogenesis. These effects by MSCs are mediated by a variety of factors, including growth factors, cytokines and extracellular vesicles (EVs). Among these factors, EVs, containing proteins, mRNA and microRNAs (miRNA), may carry their contents into distant tissues with high stability. Therefore, the treatment with MSC-derived EVs may be promising as ‘natural’ drug delivery systems (DDS). Especially, the treatment of MSC-derived EVs with the manipulation of specific miRNAs expression has been reported to be beneficial under a variety of diseases and tissue injuries. The overexpression of specific miRNAs in the EVs might be through pre-loading method using the gene editing system by plasmid vector or post-loading method to load miRNA mimics into EVs by electroporation or calcium chloride-mediated transfection. Despite current several challenges for clinical use, it should open the next era of regenerative medicine for a variety of diseases. In this article, we highlight the therapeutic potential of MSC-derived EVs as ‘natural’ DDS and current challenges.     

Characterization of Alzheimer paired helical filaments by electron microscopy

We show how electron microscopy can be used to answer several critical issues in neurodegenerative disorders that course with the formation of aberrant filamentous structures. Thus, electron microscopy is a useful technique to study in vitro assembly of pathogenic proteins, to map the regions involved in filament formation, as well as to detect by immunoelectron microscopy which proteins bind to the filaments. Furthermore, electron microscopy is the main technique used to discover if an animal model develops fibrillar pathology and if those filaments are similar to those found in human patients. This review focuses on Alzheimer's disease and related tauopathies, although similar studies have been done with other neurodegenerative disorders as, for example, Huntington's disease.     

Ultrastructural characteristics of ovine bone marrow‐derived mesenchymal stromal cells cultured with a silicon stabilized tricalcium phosphate bioceramic

Bioceramics are being used in experimental bone engineering application in association with bone marrow derived mesenchymal stem cells (BM‐MSCs) as a new therapeutic tool, but their effects on the ultrastructure of BM‐MSCs are yet unknown. In this study we report the morphological features of ovine (o)BM‐MSCs cultured with Skelite, a resorbable bioceramic based on silicon stabilized tricalcium phosphate (SiTCP), able to promote the repair of induced bone defect in sheep model. oBM‐MSCs were isolated from the iliac crest, cultured until they reached near‐confluence and incubated with SiTCP. After 48 hr the monolayers were highly damaged and only few cells adhered to the plastic. Thus, SiTCP was removed, and after washing the cells were cultured until they became confluent. Then, they were trypsinizated and processed for transmission electron microscopy (TEM) and RT‐PCR analysis. RT‐PCR displayed that oBM‐MSCs express typical surface marker for MSCs. TEM revealed the presence of electron‐lucent cells and electron‐dense cells, both expressing the CD90 surface antigen. The prominent feature of electron‐lucent cells was the concentration of cytoplasmic organelles around the nucleus as well as large surface blebs containing glycogen or profiles of endoplasmic reticulum. The dark cells had a multilocular appearance by the presence of peripheral vacuoles. Some dark cells contained endocytic vesicles, lysosomes, and glycogen aggregates. oBM‐MSCs showed different types of specialized interconnections. The comparison with ultrastructural features of untreated oBM‐MSCs suggests the light and dark cells are two distinct cell types which were differently affected by SiTCP bioceramic. Skelite cultured ovine BM‐MSCs display electron‐dense and electron‐lucent cells which are differently affected by this bioceramic. This suggests that they could play a different role in bioceramic based therapy.     

Production of mesenchymal stem cell derived-secretome as cell-free regenerative therapy and immunomodulation: A biomanufacturing perspective

The potential of mesenchymal stem cells (MSCs) in regenerative medicine has been largely known due to their capability to induce tissue regeneration in vivo with minimum inflammation during implantation. This adult stem cell type exhibit unique features of tissue repair mechanism and immune modulation mediated by their secreted factors, called secretome. Recently, the utilization of secretome as a therapeutic agent provided new insight into cell-free therapy. Nevertheless, a sufficient amount of secretome is necessary to realize their applications for translational medicine which required a proper biomanufacturing process. Several factors related to their production need to be considered to produce a clinical-grade secretome as a biological therapeutic agent. This viewpoint highlights the current challenges and considerations during the biomanufacturing process of MSCs secretome.     

Mesenchymal stem cell-derived exosomes as new remedy for the treatment of inflammatory eye diseases

Detrimental immune response has a crucially important role in the development and progression of inflammatory eye diseases. Inflammatory mediators and proteolytic enzymes released by activated immune cells induce serious injury of corneal epithelial cells and retinal ganglion cell which may result in the vision loss. Mesenchymal stem cells (MSCs) are regulatory cells which produce various immunosuppressive factors that modulate phenotype and function of inflammatory immune cells. However, several safety issues, including undesired differentiation and emboli formation, limit clinical use of MSCs. MSC-derived exosomes (MSC-Exos) are nano-sized extracellular vesicles which contain all MSC-derived immunoregulatory factors. Intraocular administration of MSC-Exos efficiently attenuated eye inflammation and significantly improved visual acuity in experimental animals without causing any severe side effects. As cell-free product, MSC-Exos addressed all safety issues related to the transplantation of MSCs. Therefore, MSC-Exos could be considered as potentially new remedy for the treatment of inflammatory eye diseases which efficacy should be explored in up-coming clinical trials.     

Dexmedetomidine alleviates oxygen and glucose deprivation-induced apoptosis in mesenchymal stem cell via downregulation of MKP-1

Bone marrow mesenchymal stem cell (MSC)-based therapy is a novel candidate for heart repair. But ischemia-reperfusion injury leads to low viability of MSC. Dexmedetomidine (Dex) has been found to protect neurons against ischemia-reperfusion injury. It remains unknown if Dex could increase the viability of MSCs under ischemia. The present study is to observe the potential protective effect of Dex on MSCs under ischemia and its underlying mechanisms. Specific mRNAs related to myocardial ischemia in the GEO database were selected from the mRNA profiles assessed in a previous study using microarray. The most dysregulated mRNAs of the specific ones from the above study were subject to bioinformatics analysis at our laboratory. These dysregulated mRNAs possibly regulated apoptosis of cardiomyocytes and were validated in vitro for their protective effect on MSCs under ischemia. MSCs were pre-treated with Dex at 10 μM concentration for 24 h under oxygen-glucose deprivation (OGD). Flow cytometry and TUNEL assay were carried out to detect apoptosis in Dex-pretreated MSCs under OGD. The relative expressions of mitogen-activated protein kinase phosphatase 1 (MKP-1) and related genes were detected by quantitative polymerase chain reaction and western blotting. Microarray data analysis revealed that Dex regulates MAPK phosphatase activity. Dex significantly reduced in vitro apoptosis of MSCs under OGD, which suppressed the synthesis level of Beclin1 and light chain 3 proteins. Dex down-regulated MKP-1 expression and attenuated an OGD-induced change in the mitogen activated protein kinase 3 (MAPK3) signaling pathway. Dex increases the viability of MSC and improves its tolerance to OGD in association with the MKP-1 signaling pathway, thus suggesting the potential of Dex as a novel strategy for promoting MSCs efficacy under ischemia.