Transcriptomic comparisons between cultured human adipose tissue-derived pericytes and mesenchymal stromal cells

The pathological and therapeutic roles of mesenchymal stem cells in preeclampsia

Mesenchymal stem cells (MSCs) have made progress in the treatment of ischemic and inflammatory diseases. Preeclampsia (PE) is characterized by placenta ischemic and inflammatory injury. Our paper summarized the new role of MSCs in PE pathology and its potency in PE therapy and analyzed its current limitations. Intravenously administered MSCs dominantly distributed in perinatal tissues. There may be additional advantages to using MSCs-based therapies for reproductive disorders. It will provide new ideas for future research in this field.

Decidualization modulates the mesenchymal stromal/stem cell and pericyte characteristics of human decidual stromal cells. Effects on antigen expression, chemotactic activity on monocytes and antitumoral activity

Decidual stromal cells (DSCs) are the most abundant cellular component of human decidua and play a central role in maternal-fetal immune tolerance. Antigen phenotyping and functional studies recently confirmed the relationship of DSCs with mesenchymal stem/stromal cells (MSCs) and pericytes, the latter two cell types being closely related or identical. The present study investigated the effect of decidualization, a process of cell differentiation driven by progesterone (P4) and other pregnancy hormones, on the MSC/pericyte characteristics of DSCs. To this end we isolated undifferentiated DSC (preDSC) lines that were decidualized in vitro (dDSC) by the effect of P4 and cAMP. Using flow cytometry, we found significant downmodulation of the expression of the MSC/pericyte markers α-smooth muscle actin, nestin, CD140b, CD146 and SUSD2 in dDSCs. The dDSCs did not differ, compared to preDSCs, in the expression of angiogenic factors (characteristic of pericytes) HGF, FGF2, ANGPT1 or VEGF according to RT-PCR results, but had significantly increased PGF expression. In migration assays, preDSC-conditioned media had a chemotactic effect on the THP-1 monocytic line (characteristic of pericytes), and this effect was significantly greater in dDSC-conditioned media. Media conditioned with dDSC, but not with preDSC, induced apoptosis in 4 out of 6 different tumor cell lines (characteristic of MSCs) according to propidium iodide staining and flow cytometry results. Our findings show that decidualization induces phenotypic and functional changes in the MSC/pericyte properties of DSCs that may have a role in the normal development of pregnancy.

Neuroprotection offered by mesenchymal stem cells in perinatal brain injury: Role of mitochondria, inflammation, and reactive oxygen species

Preclinical studies have shown that mesenchymal stem cells have a positive effect in perinatal brain injury models. The mechanisms that cause these neurotherapeutic effects are not entirely intelligible. Mitochondrial damage, inflammation, and reactive oxygen species are considered to be critically involved in the development of injury. Mesenchymal stem cells have immunomodulatory action and exert mitoprotective effects which attenuate production of reactive oxygen species and promote restoration of tissue function and metabolism after perinatal insults. This review summarizes the present state, the underlying causes, challenges and possibilities for effective clinical translation of mesenchymal stem cell therapy.

Presence/Absence and Specific Location of Resident CD34+ Stromal Cells/Telocytes Condition Stromal Cell Development in Repair and Tumors

CD34+ stromal cells/telocytes (CD34+SCs/TCs) can have a role as mesenchymal precursor cells. Our objective is to assess whether the myofibroblastic stromal cell response in repair and in desmoplastic reactions in tumors depend on the presence or absence of resident CD34+SCs/TCs in specific regions/layers of an organ and on the location of their possible subpopulations. For this purpose, using conventional and immunohistochemical procedures, we studied specimens of (a) acute cholecystitis, with early repair phenomena (n: 6), (b) surgically resected segments of colon tattooed with India ink during previous endoscopic removal of malignant polyps, with macrophage infiltration and stromal cell reaction (n: 8) and (c) infiltrative adenocarcinomas of colon, with desmoplastic reaction (n: 8). The results demonstrated (a) stromal myofibroblastic reaction during repair and tumor desmoplasia in most regions in which resident CD34+SCs/TCs are present, (b) absence of stromal myofibroblastic reaction during repair in the mucosa of both organs in which resident CD34+SCs/TCs are absent and (c) permanence of CD34+SCs/TCs as such, without myofibroblastic response, in smooth muscle fascicles, nerves, and Meissner and Auerbach plexuses, in which the CD34+SCs/TCs mainly undergo reactive phenomena. Therefore, the development of activated αSMA+ myofibroblasts in these conditions requires the presence of resident CD34+SCs/TCs and depends on their location. In conclusion, the facts support the hypotheses that CD34+SCs/TCs participate in the origin of myofibroblasts during repair and tumor stroma formation, and that there is a heterogeneous population of resident CD34+SCs/TCs with different roles.

Pro-angiogenic Activity Discriminates Human Adipose-Derived Stromal Cells From Retinal Pericytes: Considerations for Cell-Based Therapy of Diabetic Retinopathy

Diabetic retinopathy (DR) is a frequent diabetes-associated complication. Pericyte dropout can cause increased vascular permeability and contribute to vascular occlusion. Adipose-derived stromal cells (ASC) have been suggested to replace pericytes and restore microvascular support as potential therapy of DR. In models of DR, ASC not only generated a cytoprotective and reparative environment by the secretion of trophic factors but also engrafted and integrated into the retina in a pericyte-like fashion. The aim of this study was to compare the pro-angiogenic features of human ASC and human retinal microvascular pericytes (HRMVPC) in vitro. The proliferation and the expression of ASC and HRMVPC markers were compared. Adhesion to high glucose-conditioned endothelial extracellular matrix, mimicking the diabetic microenvironment, was measured. The angiogenesis-promoting features of both cell types and their conditioned media on human retinal endothelial cells (EC) were assessed. To identify a molecular basis for the observed differences, gene expression profiling was performed using whole-genome microarrays, and data were validated using PCR arrays and flow cytometry. Based on multiplex cytokine results, functional studies on selected growth factors were performed to assess their role in angiogenic support. Despite a distinct heterogeneity in ASC and HRMVPC cultures with an overlap of expressed markers, ASC differed functionally from HRMVPC. Most importantly, the pro-angiogenic activity was solely featured by ASC, whereas HRMVPC actively suppressed vascular network formation. HRMVPC, in contrast to ASC, showed impaired adhesion and proliferation on the high glucose-conditioned endothelial extracellular matrix. These data were supported by gene expression profiles with differentially expressed genes. The vessel-stabilizing factors were more highly expressed in HRMVPC, and the angiogenesis-promoting factors were more highly expressed in ASC. The vascular endothelial growth factor receptor-2 inhibition efficiently abolished the ASC angiogenic supportive capacities, whereas the addition of angiopoietin-1 and angiopoietin-2 did not alter these effects. Our results clearly show that ASC are pro-angiogenic, whereas HRMVPC are marked by anti-angiogenic/EC-stabilizing features. These data support ASC as pericyte replacement in DR but also suggest a careful risk-to-benefit analysis to take full advantage of the ASC therapeutic features.

Immunophenotyping of a Stromal Vascular Fraction from Microfragmented Lipoaspirate Used in Osteoarthritis Cartilage Treatment and Its Lipoaspirate Counterpart

Osteoarthritis (OA) is a degenerative joint disease accompanied by pain and loss of function. Adipose tissue harbors mesenchymal stem/stromal cells (MSC), or medicinal signaling cells as suggested by Caplan (Caplan, 2017), used in autologous transplantation in many clinical settings. The aim of the study was to characterize a stromal vascular fraction from microfragmented lipoaspirate (SVF-MLA) applied for cartilage treatment in OA and compare it to that of autologous lipoaspirate (SVF-LA). Samples were first stained using a DuraClone SC prototype tube for the surface detection of CD31, CD34, CD45, CD73, CD90, CD105, CD146 and LIVE/DEAD Yellow Fixable Stain for dead cell detection, followed by DRAQ7 cell nuclear dye staining, and analyzed by flow cytometry. In SVF-LA and SVF-MLA samples, the following population phenotypes were identified within the CD45⁻ fraction: CD31⁺CD34⁺CD73^±CD90^±CD105^±CD146^± endothelial progenitors (EP), CD31⁺CD34⁻CD73^±CD90^±CD105⁻CD146^± mature endothelial cells, CD31⁻CD34⁻CD73^±CD90⁺CD105⁻CD146⁺ pericytes, CD31⁻CD34⁺CD73^±CD90⁺CD105⁻CD146⁺ transitional pericytes, and CD31⁻CD34⁺CD73^highCD90⁺CD105⁻CD146⁻ supra-adventitial-adipose stromal cells (SA-ASC). The immunophenotyping profile of SVF-MLA was dominated by a reduction of leukocytes and SA-ASC, and an increase in EP, evidencing a marked enrichment of this cell population in the course of adipose tissue microfragmentation. The role of EP in pericyte-primed MSC-mediated tissue healing, as well as the observed hormonal implication, is yet to be investigated.

Human predecidual stromal cells are mesenchymal stromal/stem cells and have a therapeutic effect in an immune-based mouse model of recurrent spontaneous abortion

Background

Human decidual stromal cells (DSCs) are involved in the maintenance and development of pregnancy, in which they play a key role in the induction of immunological maternal–fetal tolerance. Precursors of DSCs (preDSCs) are located around the vessels, and based on their antigen phenotype, previous studies suggested a relationship between preDSCs and mesenchymal stromal/stem cells (MSCs). This work aimed to further elucidate the MSC characteristics of preDSCs.

Methods

We established 15 human preDSC lines and 3 preDSC clones. Physiological differentiation (decidualization) of these cell lines and clones was carried out by in vitro culture with progesterone (P4) and cAMP. Decidualization was confirmed by the change in cellular morphology and prolactin (PRL) secretion, which was determined by enzyme immunoassay of the culture supernatants. We also studied MSC characteristics: (1) In mesenchymal differentiation, under appropriate culture conditions, these preDSC lines and clones differentiated into adipocytes, osteoblasts, and chondrocytes, and differentiation was confirmed by cytochemical assays and RT-PCR. (2) The expression of stem cell markers was determined by RT-PCR. (3) Cloning efficiency was evaluated by limited dilution. (4) Immunoregulatory activity in vivo was estimated in DBA/2-mated CBA/J female mice, a murine model of immune-based recurrent abortion. (5) Survival of preDSC in immunocompetent mice was analyzed by RT-PCR and flow cytometry.

Results

Under the effect of P4 and cAMP, the preDSC lines and clones decidualized in vitro: the cells became rounder and secreted PRL, a marker of physiological decidualization. PreDSC lines and clones also exhibited MSC characteristics. They differentiated into adipocytes, osteoblasts, and chondrocytes, and preDSC lines expressed stem cell markers OCT-4, NANOG, and ABCG2; exhibited a cloning efficiency of 4 to 15%; significantly reduced the embryo resorption rate (P < 0.001) in the mouse model of abortion; and survived for prolonged periods in immunocompetent mice. The fact that 3 preDSC clones underwent both decidualization and mesenchymal differentiation shows that the same type of cell exhibited both DSC and MSC characteristics.

Conclusions

Together, our results confirm that preDSCs are decidual MSCs and suggest that these cells are involved in the mechanisms of maternal–fetal immune tolerance.

Electronic supplementary material

The online version of this article (10.1186/s13287-019-1284-z) contains supplementary material, which is available to authorized users.

Molecular signature of human bone marrow-derived mesenchymal stromal cell subsets

In the current study we compared the molecular signature of expanded mesenchymal stromal cells (MSCs) derived from selected CD271+ bone marrow mononuclear cells (CD271-MSCs) and MSCs derived from non-selected bone marrow mononuclear cells by plastic adherence (PA-MSCs). Transcriptome analysis demonstrated for the first time the upregulation of 115 and downregulation of 131 genes in CD271-MSCs. Functional enrichment analysis showed that the upregulated genes in CD271-MSCs are significantly enriched for extracellular matrix (tenascin XB, elastin, ABI family, member 3 (NESH) binding protein, carboxypeptidase Z, laminin alpha 2 and nephroblastoma overexpressed) and cell adhesion (CXCR7, GPNMB, MYBPH, SVEP1, ARHGAP6, TSPEAR, PIK3CG, ABL2 and NCAM1). CD271-MSCs expressed higher gene transcript levels that are involved in early osteogenesis/chondrogenesis/adipogenesis (ZNF145, FKBP5). In addition, increased transcript levels for early and late osteogenesis (DPT, OMD, ID4, CRYAB, SORT1), adipogenesis (CTNNB1, ZEB, LPL, FABP4, PDK4, ACDC), and chondrogenesis (CCN3/NOV, CCN4/WISP1, CCN5/WISP2 and ADAMTS-5) were detected. Interestingly, CD271-MSCs expressed increased levels of hematopoiesis associated genes (CXCL12, FLT3L, IL-3, TPO, KITL). Down-regulated genes in CD271-MSCs were associated with WNT and TGF-beta signaling, and cytokine/chemokine signaling pathways. In addition to their capacity to support hematopoiesis, these results suggest that CD271-MSCs may contain more osteo/chondro progenitors and/or feature a greater differentiation potential.

Higher Pericyte Content and Secretory Activity of Microfragmented Human Adipose Tissue Compared to Enzymatically Derived Stromal Vascular Fraction

Autologous adipose tissue is used for tissue repletion and/or regeneration as an intact lipoaspirate or as enzymatically derived stromal vascular fraction (SVF), which may be first cultured into mesenchymal stem cells (MSCs). Alternatively, transplant of autologous adipose tissue mechanically fragmented into submillimeter clusters has recently showed remarkable efficacy in diverse therapeutic indications. To document the biologic basis of the regenerative potential of microfragmented adipose tissue, we first analyzed the distribution of perivascular presumptive MSCs in adipose tissue processed with the Lipogems technology, observing a significant enrichment in pericytes, at the expense of adventitial cells, as compared to isogenic enzymatically processed lipoaspirates. The importance of MSCs as trophic and immunomodulatory cells, due to the secretion of specific factors, has been described. Therefore, we investigated protein secretion by cultured adipose tissue clusters or enzymatically derived SVF using secretome arrays. In culture, microfragmented adipose tissue releases many more growth factors and cytokines involved in tissue repair and regeneration, noticeably via angiogenesis, compared to isogenic SVF. Therefore, we suggest that the efficient tissue repair/regeneration observed after transplantation of microfragmented adipose tissue is due to the secretory ability of the intact perivascular niche. Stem Cells Translational Medicine 2018;7:876-886.

Gonadotropin and steroid hormones regulate pluripotent very small embryonic-like stem cells in adult mouse uterine endometrium

Background

Very small embryonic-like stem cells (VSELs) exist in adult organs, express pluripotent markers and have the ability to differentiate into three germ layers in vitro. Testicular, ovarian and hematopoietic stem/progenitor cells express receptors for follicle stimulating (FSH) and ovarian hormones and are activated by them to undergo proliferation/differentiation. VSELs exist in mouse uterus and are regulated by physiological dose of estradiol (E) & progesterone (P) during endometrial growth, differentiation and regeneration/remodeling. In the present study, effects of daily administration of E (2 μg/day), P (1 mg/Kg/day) or FSH (5 IU/day) for 7 days on the endometrium and stem/progenitor cells was studied in bilaterally ovariectomized mice.

Results

E treatment resulted in hypertrophy whereas P resulted in hyperplasia and overcrowding of epithelial cells. FSH also directly stimulated the endometrial cells. Nuclear OCT-4A positive VSELs were visualized in ovariectomized (atrophied) endometrium and cytoplasmic OCT-4B positive epithelial, stromal and endothelial cells were observed after treatment. FSH treated uterine tissue showed presence of 4 alternately spliced FSHR isoforms by Western blotting. 3–5 μm VSELs with a surface phenotype of LIN-/CD45-/SCA-1+ were enumerated by flow cytometry and were found to express ER, PR, FSHR1 and FSHR3 by RT-PCR analysis. Differential effects of treatment were observed on pluripotent (Oct4A, Sox2, Nanog), progenitors (Oct-4, Sca-1), primordial germ cells (Stella, Fragilis) and proliferation (Pcna) specific transcripts by qRT-PCR analysis. FSH and P (rather than E) exerted profound, direct stimulatory effects on uterine VSELs. Asymmetric, symmetric divisions and clonal expansion of stem/progenitor cells was confirmed by co-expression of OCT-4 and NUMB.

Conclusions

Results confirm presence of VSELs and their regulation by circulatory hormones in mouse uterus. Stem cell activation was more prominent after P and FSH compared to E treatment. The results question whether epithelial cells proliferation is regulated by paracrine influence of stromal cells or due to direct action of hormones on stem cells. VSELs expressing nuclear OCT-4A are the most primitive and pluripotent stem cells, undergo asymmetric cell division to self-renew and differentiate into epithelial, stromal and endothelial cells with cytoplasmic OCT-4B. Role of follicle stimulating and steroid hormones on the stem cells needs to be studied in various uterine pathologies.

Cell Connections by Tunneling Nanotubes: Effects of Mitochondrial Trafficking on Target Cell Metabolism, Homeostasis, and Response to Therapy

Intercellular communications play a major role in tissue homeostasis and responses to external cues. Novel structures for this communication have recently been described. These tunneling nanotubes (TNTs) consist of thin-extended membrane protrusions that connect cells together. TNTs allow the cell-to-cell transfer of various cellular components, including proteins, RNAs, viruses, and organelles, such as mitochondria. Mesenchymal stem cells (MSCs) are both naturally present and recruited to many different tissues where their interaction with resident cells via secreted factors has been largely documented. Their immunosuppressive and repairing capacities constitute the basis for many current clinical trials. MSCs recruited to the tumor microenvironment also play an important role in tumor progression and resistance to therapy. MSCs are now the focus of intense scrutiny due to their capacity to form TNTs and transfer mitochondria to target cells, either in normal physiological or in pathological conditions, leading to changes in cell energy metabolism and functions, as described in this review.

The double life of cardiac mesenchymal cells: Epimetabolic sensors and therapeutic assets for heart regeneration

Organ-specific mesenchymal cells naturally reside in the stroma, where they are exposed to some environmental variables affecting their biology and functions. Risk factors such as diabetes or aging influence their adaptive response. In these cases, permanent epigenetic modifications may be introduced in the cells with important consequences on their local homeostatic activity and therapeutic potential. Numerous results suggest that mesenchymal cells, virtually present in every organ, may contribute to tissue regeneration mostly by paracrine mechanisms. Intriguingly, the heart is emerging as a source of different cells, including pericytes, cardiac progenitors, and cardiac fibroblasts. According to phenotypic, functional, and molecular criteria, these should be classified as mesenchymal cells. Not surprisingly, in recent years, the attention on these cells as therapeutic tools has grown exponentially, although only very preliminary data have been obtained in clinical trials to date. In this review, we summarized the state of the art about the phenotypic features, functions, regenerative properties, and clinical applicability of mesenchymal cells, with a particular focus on those of cardiac origin.