Gene expression modifications in Wharton's Jelly mesenchymal stem cells promoted by prolonged in vitro culturing

Mesenchymal stromal cell therapies for traumatic neurological injuries

Improved treatment options are urgently needed for neurological injuries resulting from trauma or iatrogenic events causing long-term disabilities that severely impact patients' quality of life. In vitro and animal studies have provided promising proof-of-concept examples of regenerative therapies using mesenchymal stromal cells (MSC) for a wide range of pathological conditions. Over the previous decade, various MSC-based therapies have been investigated in clinical trials to treat traumatic neurological injuries. However, while the safety and feasibility of MSC treatments has been established, the patient outcomes in these studies have not demonstrated significant success in the translation of MSC regenerative therapy for the treatment of human brain and spinal cord injuries. Herein, we have reviewed the literature and ongoing registered trials on the application of MSC for the treatment of traumatic brain injury, traumatic spinal cord injury, and peripheral nerve injury. We have focused on the shortcomings and technological hurdles that must be overcome to further advance clinical research to phase 3 trials, and we discuss recent advancements that represent potential solutions to these obstacles to progress.

Comparative transcriptome analysis of bone marrow resident versus culture-expanded mouse mesenchymal stem/stromal cells

BACKGROUND AIMS

Mesenchymal stem/stromal cells (MSCs) are defined as culture-expanded populations, and although these cells recapitulate many properties of bone marrow (BM) resident skeletal stem/progenitor cells, few studies have directly compared these populations to evaluate how culture adaptation and expansion impact critical quality attributes.

METHODS

We analyzed by RNA sequencing Lin-SCA1+ MSCs enriched from BM by immunodepletion (ID) and after subsequent culture expansion (Ex) and Lin-LEPR+ MSCs sorted (S) directly from BM. Pairwise comparisons were used to identify differentially expressed genes (DEGs) between populations, and gene set enrichment analysis was employed to identify biological pathways/processes unique to each population. K-means cluster analysis resolved isolation status-dependent changes in transcription in pseudotime.

RESULTS

Hierarchical clustering segregated populations by isolation process, and principal component analysis identified transcripts related to vasculature development, ossification and inflammatory/cytokine signaling as key drivers of population variance. Pairwise comparisons identified 3849 DEGs in ID versus S BM-MSCs mapping to Gene Ontology (GO) terms related to immune and metabolic processes and 334 DEGs in Ex versus ID BM-MSCs mapping to GO terms related to tissue development, cell growth and replication and organelle organization. K-means cluster analysis revealed significant differences in transcripts encoding stemness and differentiation markers, extracellular matrix structural constituents and remodeling enzymes and paracrine-acting factors between populations.

CONCLUSIONS

These comparative analyses reveal significant differences in gene expression signatures between BM resident and culture-expanded MSCs, thereby providing new insight into how culture adaptation/expansion endows the latter with unique quality attributes.

An Overview of Mesenchymal Stem Cell Heterogeneity and Concentration

Mesenchymal stem cells (MSCs) are of great interest in cell therapies due to the immunomodulatory and other effects they have after autologous or allogeneic transplantation. In most clinical applications, a high number of MSCs is required; therefore, the isolated MSC population must be expanded in the cell culture until the desired number is reached. Analysing freshly isolated MSCs is challenging due to their rareness and heterogeneity, which is noticeable among donors, tissues, and cell subpopulations. Although the phenotype of MSCs in tissue can differ from those of cultured cells, phenotyping and counting are usually performed only after MSC proliferation. As MSC applicability is a developing and growing field, there is a need to implement phenotyping and counting methods for freshly isolated MSCs, especially in new one-step procedures where isolated cells are implanted immediately without cell culturing. Only by analysing harvested cells can we correctly evaluate such studies. This review describes multilevel heterogeneity and concentrations of MSCs and different strategies for phenotype determination and enumeration of freshly isolated MSCs.

Diameters and Fluorescence Calibration for Extracellular Vesicle Analyses by Flow Cytometry

Extracellular vesicles (EVs) play a crucial role in the intercellular crosstalk. Mesenchymal stem cell-derived EVs (MSC-EVs), displaying promising therapeutic roles, contribute to the strong rationale for developing EVs as an alternative therapeutic option. EV analysis still represents one of the major issues to be solved in order to translate the use of MSC-EV detection in clinical settings. Even if flow cytometry (FC) has been largely applied for EV studies, the lack of consensus on protocols for FC detection of EVs generated controversy. Standard FC procedures, based on scatter measurements, only allows the detection of the “tip of the iceberg” of all EVs. We applied an alternative FC approach based on the use of a trigger threshold on a fluorescence channel. The EV numbers obtained by the application of the fluorescence triggering resulted significantly higher in respect to them obtained from the same samples acquired by placing the threshold on the side scatter (SSC) channel. The analysis of EV concentrations carried out by three different standardized flow cytometers allowed us to achieve a high level of reproducibility (CV < 20%). By applying the here-reported method highly reproducible results in terms of EV analysis and concentration measurements were obtained.

Expanded Differentiation Capability of Human Wharton's Jelly Stem Cells Toward Pluripotency: A Systematic Review

Human Wharton's jelly stem cells (HWJSC) can be efficiently isolated from the umbilical cord, and numerous reports have demonstrated that these cells can differentiate into several cell lineages. This fact, coupled with the high proliferation potential of HWJSC, makes them a promising source of stem cells for use in tissue engineering and regenerative medicine. However, their real potentiality has not been established to date. In the present study, we carried out a systematic review to determine the multilineage differentiation potential of HWJSC. After a systematic literature search, we selected 32 publications focused on the differentiation potential of these cells. Analysis of these studies showed that HWJSC display expanded differentiation potential toward some cell types corresponding to all three embryonic cell layers (ectodermal, mesodermal, and endodermal), which is consistent with their constitutive expression of key pluripotency markers such as OCT4, SOX2, and NANOG, and the embryonic marker SSEA4. We conclude that HWJSC can be considered cells in an intermediate state between multipotentiality and pluripotentiality, since their proliferation capability is not unlimited and differentiation to all cell types has not been demonstrated thus far. These findings support the clinical use of HWJSC for the treatment of diseases affecting not only mesoderm-type tissues but also other cell lineages. Impact statement Human Wharton's jelly stem cells (HWJSC) are mesenchymal stem cells that are easy to isolate and handle, and that readily proliferate. Their wide range of differentiation capabilities supports the view that these cells can be considered pluripotent. Accordingly, HWJSC are one of the most promising cell sources for clinical applications in advanced therapies.

Therapeutic Potential of Wharton's Jelly Mesenchymal Stem Cells for Diabetes: Achievements and Challenges

Diabetes mellitus (DM) is an alarming metabolic disease in which insulin secreting β-cells are damaged to various extent. Unfortunately, although currently available treatments help to manage the disease, however, patients usually develop complications, as well as decreased life quality and increased mortality. Thus, efficient therapeutic interventions to treat diabetes are urgently warranted. During the past years, mesenchymal stem cells (MSCs) have made their mark as a potential weapon in various regenerative medicine applications. The main fascination about MSCs lies in their potential to exert reparative effects on an amazingly wide spectrum of tissue injury. This is further reinforced by their ease of isolation and large ex vivo expansion capacity, as well as demonstrated multipotency and immunomodulatory activities. Among all the sources of MSCs, those isolated from umbilical cord-Wharton's jelly (WJ-MSCs), have been proved to provide a great source of MSCs. WJ-MSCs do not impose any ethical concerns as those which exist regarding ESCs, and represent a readily available non-invasive source, and hence suggested to become the new gold standard for MSC-based therapies. In the current review, we shall overview achievements, as well as challenges/hurdles which are standing in the way to utilize WJ-MSCs as a novel efficient therapeutic modality for DM.

Accumulating Transcriptome Drift Precedes Cell Aging in Human Umbilical Cord-Derived Mesenchymal Stromal Cells Serially Cultured to Replicative Senescence

In preclinical studies, mesenchymal stromal cells (MSCs) exhibit robust potential for numerous applications. To capitalize on these benefits, cell manufacturing and delivery protocols have been scaled up to facilitate clinical trials without adequately addressing the impact of these processes on cell utility nor inevitable regulatory requirements for consistency. Growing evidence indicates that culture-aged MSCs, expanded to the limits of replicative exhaustion to generate human doses, are not equivalent to early passage cells, and their use may underpin reportedly underwhelming or inconsistent clinical outcomes. Here, we sought to define the maximum expansion boundaries for human umbilical cord-derived MSCs, cultured in chemically defined xeno- and serum-free media, that yield consistent cell batches comparable to early passage cells. Two male and two female donor populations, recovered from cryostorage at mean population doubling level (mPDL) 10, were serially cultivated until replicative exhaustion (senescence). At each passage, growth kinetics, cell morphology, and transcriptome profiles were analyzed. All MSC populations displayed comparable growth trajectories through passage 9 (P9; mPDL 45) and variably approached senescence after P10 (mPDL 49). Transcription profiles of 14,500 human genes, generated by microarray, revealed a nonlinear evolution of culture-adapted MSCs. Significant expression changes occurred only after P5 (mPDL 27) and accumulated rapidly after P9 (mPDL 45), preceding other cell aging metrics. We report that cryobanked umbilical cord-derived MSCs can be reliably expanded to clinical human doses by P4 (mPDL 23), before significant transcriptome drift, and thus represent a mesenchymal cell source suited for clinical translation of cellular therapies. Stem Cells Translational Medicine 2019;8:945&958.

Manufacturing of primed mesenchymal stromal cells for therapy

Mesenchymal stromal cells (MSCs) for basic research and clinical applications are manufactured and developed as unique cell products by many different manufacturers and laboratories, often under different conditions. The lack of standardization of MSC identity has limited consensus around which MSC properties are relevant for specific outcomes. In this Review, we examine how the choice of media, cell source, culture environment and storage affects the phenotype and clinical utility of MSC-based products, and discuss the techniques better suited to prime MSCs with specific phenotypes of interest and the need for the continued development of standardized assays that provide quality assurance for clinical-grade MSCs. Bioequivalence between cell products and batches must be investigated rather than assumed, so that the diversity of phenotypes between differing MSC products can be accounted for to identify products with the highest therapeutic potential and to preserve their safety in clinical treatments.

Therapeutic potential of hAECs for early Achilles tendon defect repair through regeneration

Cell-based therapy holds great promise for tendon disorders, a widespread debilitating musculoskeletal condition. Even if the cell line remains to be defined, preliminary evidences have proven that amniotic-derived cells possess in vitro and in vivo a great tenogenic potential. This study investigated the efficacy of transplanted human amniotic epithelial cells (hAECs) by testing their early regenerative properties and mechanisms involved on a validated ovine Achilles tendon partial defect performed on 29 animals. The injured tendons treated with hAECs recovered rapidly, in 28 days, structural and biomechanical properties undertaking a programmed tissue regeneration, differently from the spontaneous healing tissues. hAECs remained viable within the host tendons establishing with the endogenous progenitor cells an active dialogue. Through the secretion of modulatory factors, hAECs inhibited the inflammatory cells infiltration, activated the M2 macrophage subpopulation early recruitment, and accelerated blood vessel as well as extracellular matrix remodelling. In parallel, some in situ differentiated hAECs displayed a tenocytelike phenotype. Both paracrine and direct hAECs stimulatory effects were confirmed analysing their genome profile before and after transplantation. The 49 human up-regulated transcripts recorded in transplanted hAECs belonged to tendon lineage differentiation (epithelial-mesenchymal transition, connective specific matrix components, and skeleton or muscle system development-related transcripts), as well as the in situ activation of paracrine signalling involved in inflammatory and immunomodulatory response. Altogether, these evidences support the hypothesis that hAECs are a practicable and efficient strategy for the acute treatment of tendinopathy, reinforcing the idea of a concrete use of amniotic epithelial cells towards the clinical practice.

Cellularizing hydrogel-based scaffolds to repair bone tissue: How to create a physiologically relevant micro-environment?

Tissue engineering is a promising alternative to autografts or allografts for the regeneration of large bone defects. Cell-free biomaterials with different degrees of sophistication can be used for several therapeutic indications, to stimulate bone repair by the host tissue. However, when osteoprogenitors are not available in the damaged tissue, exogenous cells with an osteoblast differentiation potential must be provided. These cells should have the capacity to colonize the defect and to participate in the building of new bone tissue. To achieve this goal, cells must survive, remain in the defect site, eventually proliferate, and differentiate into mature osteoblasts. A critical issue for these engrafted cells is to be fed by oxygen and nutrients: the transient absence of a vascular network upon implantation is a major challenge for cells to survive in the site of implantation, and different strategies can be followed to promote cell survival under poor oxygen and nutrient supply and to promote rapid vascularization of the defect area. These strategies involve the use of scaffolds designed to create the appropriate micro-environment for cells to survive, proliferate, and differentiate in vitro and in vivo. Hydrogels are an eclectic class of materials that can be easily cellularized and provide effective, minimally invasive approaches to fill bone defects and favor bone tissue regeneration. Furthermore, by playing on their composition and processing, it is possible to obtain biocompatible systems with adequate chemical, biological, and mechanical properties. However, only a good combination of scaffold and cells, possibly with the aid of incorporated growth factors, can lead to successful results in bone regeneration. This review presents the strategies used to design cellularized hydrogel-based systems for bone regeneration, identifying the key parameters of the many different micro-environments created within hydrogels.

Transcriptome modifications in human gingival fibroblasts exposed to 2-hydroxyethyl methacrylate

2-Hydroxyethyl methacrylate (HEMA),a tooth filling material, was proven to have toxic effects on different cell types, including human gingival fibroblasts (HGFs), and to be able to influence odontoblast vitality. The aim of the present study was to assess the differential transcriptome modulation induced by low HEMA concentration in cultured HGFs. RNA extracted from cultured HGFs exposed to 3 mmol/l HEMA for 24 or 96 h underwent a whole genome microarray analysis. Data analysis showed the presence of two gene clusters, composed by 310 transcripts differentially expressed after 24- and 96-h HEMA treatment compared to controls. Functional analysis demonstrated that these transcripts are mainly involved in cellular survival and death, and inflammatory response. The study highlighted an overall damage induced by HEMA exposure at both 24 and 96 h, mainly leading to a proliferation impairment. Interestingly, 24-h HEMA treatment seems to induce the cells to trigger repair mechanisms, evidencing an early compensatory response, whereas 96-h incubation appears to cause the occurrence of apoptosis as a consequence of the chronic damage.

Assessment of an efficient xeno-free culture system of human periodontal ligament stem cells

The possibility of transplanting adult stem cells into damaged organs has opened new prospects for the treatment of several human pathologies. The purpose of this study was to develop a culture system for the expansion and production of human Periodontal Ligament Stem Cells (hPDLSCs) using a new xeno-free media formulation and ensuring the maintenance of the stem cells features comprising the multiple passage expansion, mesengenic lineage differentiation, cellular phenotype, and genomic stability, essential elements for conforming to translation to cell therapy. Somatic stem cells were isolated from the human periodontium using a minimally invasive periodontal access flap surgery in healthy donors. Expanded hPDLSCs in a xeno-free culture showed the morphological features of stem cells, expressed the markers associated with pluripotency, and a normal karyotype. Under appropriate culture conditions, hPDLSCs presented adipogenic and osteogenic potential; indeed, a very high accumulation of lipid droplets was evident in the cytoplasm of adipogenic-induced cells, and indisputable evidence of osteogenic differentiation, investigated by transmission electron microscopy, and analyzed for gene expression analysis has been shown. Based on these data, the novel xeno-free culture method might provide the basis for Good Manufacturing Procedure culture of autologous stem cells, readily accessible from human periodontium, and can be a resource to facilitate their use in human clinical studies for potential therapeutic regeneration.

Molecular and phenotypic characterization of human amniotic fluid-derived cells: a morphological and proteomic approach

Mesenchymal Stem Cells derived from Amniotic Fluid (AFMSCs) are multipotent cells of great interest for regenerative medicine. Two predominant cell types, that is, Epithelial-like (E-like) and Fibroblast-like (F-like), have been previously detected in the amniotic fluid (AF). In this study, we examined the AF from 12 donors and observed the prevalence of the E-like phenotype in 5, whereas the F-like morphology was predominant in 7 samples. These phenotypes showed slight differences in membrane markers, with higher CD90 and lower Sox2 and SSEA-4 expression in F-like than in E-like cells; whereas CD326 was expressed only in the E-like phenotype. They did not show any significant differences in osteogenic, adipogenic or chondrogenic differentiation. Proteomic analysis revealed that samples with a predominant E-like phenotype (HC1) showed a different profile than those with a predominant F-like phenotype (HC2). Twenty-five and eighteen protein spots were differentially expressed in HC1 and HC2 classes, respectively. Of these, 17 from HC1 and 4 from HC2 were identified by mass spectrometry. Protein-interaction networks for both phenotypes showed strong interactions between specific AFMSC proteins and molecular chaperones, such as preproteasomes and mature proteasomes, both of which are important for cell cycle regulation and apoptosis. Collectively, our results provide evidence that, regardless of differences in protein profiling, the prevalence of E-like or F-like cells in AF does not affect the differentiation capacity of AFMSC preparations. This may be valuable information with a view to the therapeutic use of AFMSCs.

Deregulation of sertoli and leydig cells function in patients with Klinefelter syndrome as evidenced by testis transcriptome analysis

Background

Klinefelter Syndrome (KS) is the most common abnormality of sex chromosomes (47,XXY) and represents the first genetic cause of male infertility. Mechanisms leading to KS testis degeneration are still not completely defined but considered to be mainly the result of germ cells loss. In order to unravel the molecular basis of global testis dysfunction in KS patients, we performed a transcriptome analysis on testis biopsies obtained from 6 azoospermic non-mosaic KS patients and 3 control subjects.

Results

The analysis found that, compared to controls, KS patients showed the differential up- and down-expression of 656 and 247 transcripts. The large majority of the deregulated transcripts were expressed by Sertoli cells (SCs) and Leydig cells (LCs). Functional analysis of the deregulated transcripts indicated changes of genes involved in cell death, inflammatory response, lipid metabolism, steroidogenesis, blood-testis-barrier formation and maintenance, as well as spermatogenesis failure.

Conclusions

Taken together, present data highlight the modulation of hundreds of genes in the somatic components of KS patient testis. The increased LCs steroidogenic function together with the impairment of inflammatory pathways and BTB structure, result in increased apoptosis. These findings may represent a critical roadmap for therapeutic intervention and prevention of KS-related testis failure.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1356-0) contains supplementary material, which is available to authorized users.

Cryopreservation effects on Wharton's Jelly Stem Cells proteome

Cryopreservation is the only method for long-term storage of viable cells and tissues used for cellular therapy, stem cell transplantation and/or tissue engineering. However, the freeze-thaw process strongly contributes to cell and tissue damage through several mechanisms, including oxidative stress, cell injury from intracellular ice formation and altered physical cellular properties. Our previous proteomics investigation was carried out on Wharton's Jelly Stem Cells (WJSCs) having similar properties to adult mesenchymal stem cells and thus representing a rich source of primitive cells to be potentially used in regenerative medicine. The aim of the present work was to investigate molecular changes that occur in WJSCs proteome in different experimental conditions: fresh primary cell culture and frozen cell. To analyze changes in protein expression of WJSCs undergoing different culturing procedures, we performed a comparative proteomic analysis (2DE followed by MALDI-TOF MS/MS nanoESI-Q-TOF MS coupled with nanoLC) between WJSCs from fresh and frozen cell culturing, respectively. Frozen WJSCs showed qualitative and quantitative changes compared to cells from fresh preparation, expressing proteins involved in replication, cellular defence mechanism and metabolism, that could ensure freeze-thaw survival. The results of this study could play a key role in elucidating possible mechanisms related to maintaining active proliferation and maximal cellular plasticity and thus making the use of WJSCs in cell therapy safe following bio-banking.

Comparison of mesenchymal stem cell markers in multiple human adult stem cells

OBJECTIVES

Mesenchymal stem cells (MSCs) are adult stem cells which identified by adherence to plastic, expression of cell surface markers including CD44, CD90, CD105, CD106, CD166, and Stro-1, lack of the expression of hematopoietic markers, no immunogenic effect and replacement of damaged tissues. These properties led to development of progressive methods to isolation and characterization of MSCs from various sources for therapeutic applications in regenerative medicine.

METHODS

We isolated MSC-like cells from testis biopsies, ovary, hair follicle and umbilical cord Wharton's jelly and investigated the expression of specific cell surface antigens using flow cytometry in order to verify stemness properties of these cells.

RESULTS

All four cell types adhered to plastic culture flask a few days after primary culture. All our cells positively expressed common MSC- specific cell surface markers. Moreover, our results revealed the expression of CD19and CD45 antigens in these cells.

CONCLUSION

According to our results, high expression of CD44 in spermatogonial stem cells (SSCs), hair follicle stem cells (HFSCs),granulosa cells (GCs)and Wharton's jelly- MSCs (WJ-MSCs)may help them to maintain stemness properties. Furthermore, we suggest that CD105+SSCs, HFSCs and WJ-MSCs revealed the osteogenic potential of these cells. Moreover, high expression of CD90 in SSCs and HFSCs may associate to higher growth and differentiation potential of these cells. Further, the presence of CD19 on SSCs and GCs may help them to efficiency in response to trans-membrane signals. Thus, these four types of MSCs may be useful in clinical applications and cell therapy.

Calcium-sensing receptor-mediated osteogenic and early-stage neurogenic differentiation in umbilical cord matrix mesenchymal stem cells from a large animal model

BACKGROUND

Umbilical cord matrix mesenchymal stem cells (UCM-MSCs) present a wide range of potential therapeutical applications. The extracellular calcium-sensing receptor (CaSR) regulates physiological and pathological processes. We investigated, in a large animal model, the involvement of CaSR in triggering osteogenic and neurogenic differentiation of two size-sieved UCM-MSC lines, by using AMG641, a novel potent research calcimimetic acting as CaSR agonist.

METHODOLOGY/PRINCIPAL FINDINGS

Large (>8 µm in diameter) and small (<8 µm) equine UCM-MSC lines were cultured in medium with high calcium (Ca2+) concentration ([Ca2+]o; 2.87 mM) and dose-response effects of AMG641 (0.01 to 3µM) on cell proliferation were evaluated. Both cell lines were then cultured in osteogenic or neurogenic differentiation medium containing: 1) low [Ca2+]o (0.37 mM); 2) high [Ca2+]o (2.87 mM); 3) AMG641 (0.05, 0.1 or 1 µM) with high [Ca2+]o and 4) the CaSR antagonist NPS2390 (10 mM for 30 min) followed by incubation with AMG641 in high [Ca2+]o. Expression of osteogenic or neurogenic differentiation biomarkers was compared among groups. In both cell lines, AMG641 dose-dependently increased cell proliferation (up to P<0.001). Osteogenic molecular markers expression was differentially regulated by AMG641, with stimulatory (OPN up-regulation) in large or inhibitory (RUNX2 and OPN down-regulation) effects in small cells, respectively. AMG641 significantly increased alkaline phosphatase activity and calcium phosphate deposition in both cell lines. Following treatment with AMG641 during osteogenic differentiation, in both cell lines CaSR expression was inversely related to that of osteogenic markers and inhibition of CaSR by NPS2390 blocked AMG641-dependent responses. Early-stage neurogenic differentiation was promoted/triggered by AMG641 in both cell lines, as Nestin and CaSR mRNA transcription up-regulation were observed.

CONCLUSIONS/SIGNIFICANCE

Calcium- and AMG641-induced CaSR stimulation promoted in vitro proliferation and osteogenic and early-stage neurogenic differentiation of UCM-MSCs. CaSR activation may play a fundamental role in selecting specific differentiation checkpoints of these two differentiation routes, as related to cell commitment status.