mRNAs and miRNAs profiling of mesenchymal stem cells derived from amniotic fluid and skin: the double face of the coin

PCR Array Profiling of miRNA Expression Involved in the Differentiation of Amniotic Fluid Stem Cells toward Endothelial and Smooth Muscle Progenitor Cells

Differentiation of amniotic fluid stem cells (AFSCs) into multiple lineages is controlled by epigenetic modifications, which include DNA methylation, modifications of histones, and the activity of small noncoding RNAs. The present study investigates the role of miRNAs in the differentiation of AFSCs and addresses how their unique signatures contribute to lineage-specific differentiation. The miRNA profile was assessed in AFSCs after 4 weeks of endothelial and muscular differentiation. Our results showed decreased expression of five miRNAs (miR-18a-5p, miR-125b-5p, miR-137, miR-21-5p, and let-7a) and increased expression of twelve miRNAs (miR-134-5p, miR-103a-3p, let-7i-5p, miR-214-3p, let-7c-5p, miR-129-5p, miR-210-3p, let-7d-5p, miR-375, miR-181-5p, miR-125a-5p, and hsa-let-7e-5p) in endothelial progenitor cells (EPCs) compared with undifferentiated AFSCs. AFSC differentiation into smooth muscle revealed notable changes in nine out of the 84 tested miRNAs. Among these, three miRNAs (miR-18a-5p, miR-137, and sa-miR-21-5p) were downregulated, while six miRNAs (miR-155-5p, miR-20a-5p, let-7i-5p, hsa-miR-134-5p, hsa-miR-214-3p, and hsa-miR-375) exhibited upregulation. Insights from miRNA networks promise future advancements in understanding and manipulating endothelial and muscle cell dynamics. This knowledge has the potential to drive innovation in areas like homeostasis, growth, differentiation, and vascular function, leading to breakthroughs in biomedical applications and therapies.

Apoptotic effects of human amniotic fluid mesenchymal stem cells conditioned medium on human MCF-7 breast cancer cell line

Introduction

Breast cancer, as the most common malignancy among women, is shown to have a high mortality rate and resistance to chemotherapy. Research has shown the possible inhibitory role of Mesenchymal stem cells in curing cancer. Thus, the present work used human amniotic fluid mesenchymal stem cell-conditioned medium (hAFMSCs-CM) as an apoptotic reagent on the human MCF-7 breast cancer cell line.

Methods

Conditioned medium (CM) was prepared from hAFMSCs. After treating MCF-7 cells with CM, a number of analytical procedures (MTT, real-time PCR, western blot, and flow cytometry) were recruited to evaluate the cell viability, Bax and Bcl-2 gene expression, P53 protein expression, and apoptosis, respectively. Human fibroblast cells (Hu02) were used as the negative control. In addition, an integrated approach to meta-analysis was performed.

Results

The MCF-7 cells' viability was decreased significantly after 24 hours (P < 0.0001) and 72 hours (P < 0.05) of treatment. Compared with the control cells, Bax gene's mRNA expression increased and Bcl-2's mRNA expression decreased considerably after treating for 24 hours with 80% hAFMSCs-CM (P = 0.0012, P < 0.0001, respectively); an increasing pattern in P53 protein expression could also be observed. The flow cytometry analysis indicated apoptosis. Results from literature mining and the integrated meta-analysis showed that hAFMSCs-CM is able to activate a molecular network where Bcl2 downregulation stands in harmony with the upregulation of P53, EIF5A, DDB2, and Bax, leading to the activation of apoptosis.

Conclusion

Our finding demonstrated that hAFMSCs-CM presents apoptotic effect on MCF-7 cells; therefore, the application of hAFMSCs-CM, as a therapeutic reagent, can suppress breast cancer cells' viabilities and induce apoptosis.

Mesenchymal Stem Cells Exposed to Persistently High Glucocorticoid Levels Develop Insulin-Resistance and Altered Lipolysis: A Promising In Vitro Model to Study Cushing's Syndrome

BACKGROUND

In Cushing's syndrome (CS), chronic glucocorticoid excess (GC) and disrupted circadian rhythm lead to insulin resistance (IR), diabetes mellitus, dyslipidaemia and cardiovascular comorbidities. As undifferentiated, self-renewing progenitors of adipocytes, mesenchymal stem cells (MSCs) may display the detrimental effects of excess GC, thus revealing a promising model to study the molecular mechanisms underlying the metabolic complications of CS.

METHODS

MSCs isolated from the abdominal skin of healthy subjects were treated thrice daily with GCs according to two different regimens: lower, circadian-decreasing (Lower, Decreasing Exposure, LDE) versus persistently higher doses (Higher, Constant Exposure, HCE), aimed at mimicking either the physiological condition or CS, respectively. Subsequently, MSCs were stimulated with insulin and glucose thrice daily, resembling food uptake and both glucose uptake/GLUT-4 translocation and the expression of LIPE, ATGL, IL-6 and TNF-α genes were analyzed at predefined timepoints over three days.

RESULTS

LDE to GCs did not impair glucose uptake by MSCs, whereas HCE significantly decreased glucose uptake by MSCs only when prolonged. Persistent signs of IR occurred after 30 hours of HCE to GCs. Compared to LDE, MSCs experiencing HCE to GCs showed a downregulation of lipolysis-related genes in the acute period, followed by overexpression once IR was established.

CONCLUSIONS

Preserving circadian GC rhythmicity is crucial to prevent the occurrence of metabolic alterations. Similar to mature adipocytes, MSCs suffer from IR and impaired lipolysis due to chronic GC excess: MSCs could represent a reliable model to track the mechanisms involved in GC-induced IR throughout cellular differentiation.

Pro-inflammatory cytokines and microRNAs in male infertility

Background

Male infertility is a problem that affects 10–15% of men of reproductive age. In particular, gametogenesis is a complex process in which inflammation may play a central role through the secretion of cytokines and the expression of microRNAs. We assessed the potential role of proinflammatory cytokines (TNF-α, IL-6 and IL-1α) and microRNAs (miR-146a-5p, miR-34a-5p and miR-23a-3p) in the seminal plasma of infertile men compared to controls, evaluating their correlation with seminal and biochemical parameters.

Methods and results

Expression of cytokines and microRNAs was analyzed by ELISA and q-PCR. Our data shows that IL-1α was significantly increased in the azoospermic group compared to controls, TNF-α mRNA was more expressed in the oligozoospermic group than controls. There were no significant differences in miRNAs expression among the three groups. The correlations between sperm parameters and inflammatory markers were evaluated, however no significance was highlighted.

Conclusions

The determination of each inflammatory marker separately in the seminal plasma of subfertile men, despite some significant differences, does not have a diagnostic value in male infertility even if an assay of selective pro-inflammatory cytokines and microRNAs in the semen may improve the diagnosis of male infertility.

How the Pathological Microenvironment Affects the Behavior of Mesenchymal Stem Cells in the Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic disease characterized by fibroblasts activation, ECM accumulation, and diffused alveolar inflammation. The role of inflammation in IPF is still controversial and its involvement may follow nontraditional mechanisms. It is seen that a pathological microenvironment may affect cells, in particular mesenchymal stem cells (MSCs) that may be able to sustain the inflamed microenvironment and influence the surrounding cells. Here MSCs have been isolated from fibrotic (IPF-MSCs) and control (C-MSCs) lung tissue; first cells were characterized and compared by the expression of molecules related to ECM, inflammation, and other interdependent pathways such as hypoxia and oxidative stress. Subsequently, MSCs were co-cultured between them and with NHLF to test the effects of the cellular crosstalk. Results showed that pathological microenvironment modified the features of MSCs: IPF-MSCs, compared to C-MSCs, express higher level of molecules related to ECM, inflammation, oxidative stress, and hypoxia; notably, when co-cultured with C-MSCs and NHLF, IPF-MSCs are able to induce a pathological phenotype on the surrounding cell types. In conclusion, in IPF the pathological microenvironment affects MSCs that in turn can modulate the behavior of other cell types favoring the progression of IPF.

From 2646 to 15: differentially regulated microRNAs between progenitors from normal myometrium and leiomyoma

BACKGROUND

Uterine leiomyomas (fibroids) are smooth muscle neoplasms of the myometrial layer of the uterus and are the most common benign tumors in women. Although their etiology is still unclear, progenitor cells seem to be implicated.

OBJECTIVE

To identify the dysregulated pathways involved in leiomyoma onset by microRNA profiling of progenitor cells isolated from normal myometrium and leiomyoma tissue.

MATERIALS AND METHODS

Pairs of normal myometrium and uterine fibroid specimens were collected from 12 myomectomy patients. Myometrial progenitor cells and leiomyoma progenitor cells were isolated and characterized for stemness. After total RNA extraction and profiling of their 2646 microRNAs, DIANA-miRPath analysis was applied to find any dysregulated pathways.

RESULTS

Only 30 microRNAs showed a significant differential regulation between myometrial progenitor cells and leiomyoma progenitor cells. Removal of those that had values close to the cut-off or that were not consistent among triplicates left 15 microRNAs, of which 7 were downregulated and 8 were upregulated in leiomyoma progenitor cells compared to myometrial progenitor cells. According to DIANA-miRPath analysis, the 7 downregulated microRNAs (hsa-miR-146b-5p; hsa-miR-335-3p; hsa-miR-335-5p; hsa-miR-135b-5p; hsa-miR-10a-3p; hsa-miR-10a-5p; hsa-miR-200a-3p) are all related to 3 pathways, "ECM-receptor interaction" (33 targeted genes), "Adherens junction" (33 targeted genes), and "Hippo signaling" (69 targeted genes), whereas the 8 upregulated miRNAs (hsa-miR-146a-5p; hsa-miR-576-3p; hsa-miR-122-5p; hsa-miR-1246; hsa-miR-595; hsa-miR-658; hsa-miR-4284; hsa-miR-924) are related to 4 pathways, "PI3K-Akt signaling pathway" (71 targeted genes), "Pathways in Cancer" (80 targeted genes), "Cell Cycle" (37 targeted genes), and "Regulation of actin cytoskeleton" (41 targeted genes).

CONCLUSION

The findings that only 15 of 2646 microRNAs are differentially regulated in normal myometrium and leiomyoma and that they are involved in 7 dysregulated pathways provides interesting insights into the development of uterine fibroids, and lends support to the hypothesis that leiomyoma onset is the result of alterations affecting progenitor cells.

Gestational diabetes and maternal obesity are associated with sex-specific changes in miRNA and target gene expression in the fetus

Background/Objective

Pregnancies complicated by gestational diabetes (GDM) or maternal obesity have been linked to the development of diabetes, obesity and fatty liver disease later in life with sex-specific manifestations. Alterations in miRNA expression in offspring exposed to GDM and maternal obesity and effects on hepatic development are unknown. Here we describe how exposure to maternal obesity in utero leads to sex-specific changes in miRNA and target gene expression in human fetal liver.

Methods

Candidate miRNA expression was measured in 2^nd trimester amniotic fluid (AF) from women with GDM. Targets of differentially expressed miRNAs were determined and pathway enrichment of target genes was performed. MiRNA and target gene expression were measured in a separate cohort of 2^nd trimester primary human fetal hepatocytes (PHFH) exposed to maternal obesity via QPCR and western blot. All studies were IRB approved.

Results

GDM exposed AF had significant increases in miRNAs 199a-3p, 503-5p, and 1268a (fold change (FC) ≥1.5, p<0.05). Female offspring specific analysis showed enrichment in miRNAs 378a-3p, 885-5p, and 7-1-3p (p<0.05). MiRNA gene targets were enriched in hepatic pathways. Key genes regulating de novo lipogenesis were upregulated in obesity exposed PHFH, especially in males. Significantly altered miRNAs in GDM AF were measured in obese exposed PHFH, with consistent increases in miRNAs 885-5p, 199-3p, 503-5p, 1268a and 7-1-3p (FC ≥1.5, p<0.05). Female PHFH exposed to maternal obesity had increased expression of miR-885-5p, miR-199-3p, miR-503-5p, miR-1268s and miR-7-1-3p, (p<0.05), corresponding to decreased target genes expression for ABCA1, PAK4 and INSR. In male PHFHs, no miRNA changes were measured but there was increased expression of ABCA1, PAK4, and INSR (p<0.05).

Conclusion

Our data suggest sex-specific changes in miRNA and gene expression in PHFH may be one mechanism contributing to the sexual dimorphism of metabolic disease in offspring exposed to GDM and maternal obesity in utero.

Cushing Syndrome: The Role of MSCs in Wound Healing, Immunosuppression, Comorbidities, and Antioxidant Imbalance

Cushing syndrome (CS), caused by glucocorticoid (GCs) excess, is strictly connected to onset of different metabolic diseases and impaired wound healing. The source of excessively high levels of GCs allows the identification of endogenous and exogenous (iatrogenic) CS. Iatrogenic patients usually receive also anti-metabolites serving as the foundation to modern steroid-sparing immunosuppressive therapy. Tissues mainly targeted by CS are bone and fat, both derived from progenitor cells named mesenchymal stem cells (MSCs). In addition, the pathogenic role of MSCs in other diseases sharing common properties with CS, such as an altered inflammatory profile and increased oxidative stress, has been identified. In this light, MSCs isolated from skin of control healthy subjects (C-MSCs), patients affected by endogenous CS (ENDO-MSCs), patients affected by iatrogenic CS (IATRO-MSCs) and patients affected by exogenous CS receiving steroid-sparing drugs (SS-MSCs), respectively, have been isolated and analyzed. ENDO- and IATRO-MSCs showed a reduced differentiative potential toward osteogenic and adipogenic lineages compared to C-MSCs, whereas SS-MSCs re-acquired the ability to differentiate, with a trend similar to control cells. In addition, MSCs from CS groups, compared to control MSCs, displayed a reduction in the secretion of cytokines (immune-suppression), a decreased expression of genes related to wound healing and a dysregulation of the enzymes/genes related to antioxidant capacity. In conclusion, our results suggest that the hallmarks of CS, such as wound healing impairment and immunosuppression, are already detectable in undifferentiated cells, which could be considered a potential therapeutic early target for control of CS.

Epigenetic regulation of amniotic fluid mesenchymal stem cell differentiation to the mesodermal lineages at normal and fetus-diseased gestation

Human mesenchymal stem cells isolated from amniotic fluid (AF-MSCs) demonstrate the potency for self-renewal and multidifferentiation, and can, therefore, be a potential alternative source of stem cells adapted for therapeutic purposes. The object of this study is to evaluate the efficacy of MSCs from AF when the pregnancy is normal or when the fetus is affected during pregnancy to differentiate into mesodermal lineage tissues and to elucidate epigenetic states responsible for terminal adipogenic and osteogenic differentiation. The morphology of AF-MSCs from two cell sources and the expression of the cell surface-specific (CD44, CD90, and CD105) markers and pluripotency (Oct4, Nanog, Sox2, and Rex1) genes were quite similar and underwent mesodermal lineage differentiation because this is shown by the typical cell morphology and of genes' expression specific for adipogenic (peroxisome proliferator-activated receptor-ɣ, adiponectin) and osteoblastic (alkaline phosphatase, osteopontin, and osteocalcin) differentiation. Terminal lineage-specific differentiation was related to differential expression of miR-17, miR-21, miR-34a, and miR-146a, decreased levels of acetylated H4 and H3K9, trimethylated H3K4 and H3K9, and the retention of H3K27me3 along with a reduction in the levels of HDAC1, DNMT1, and PRC1/2 proteins (BMI1/SUZ12). No significant distinction could be identified in the levels of expression of all epigenetic or pluripotency markers between undifferentiated MSCs isolated from AF of normal gestation and pregnancy where the fetus was damaged and between those differentiated toward adipocytes or osteoblasts. The expressional changes of those marks and microRNAs that occurred during terminal differentiation to mesodermal tissues indicate subtle epigenetic regulation in AF-MSCs when the condition of the fetus is healthy normal or diseased. More detailed studies of epigenetic mechanisms may offer a better understanding of AF-MSCs differentiation in fetus-diseased conditions and their usage in an autologous therapeutic application and prenatal disease research.

The senescent status of endothelial cells affects proliferation, inflammatory profile and SOX2 expression in bone marrow-derived mesenchymal stem cells

Human aging is a physiological process characterized by a chronic low-grade inflammation. Senescence may affect endothelial cells, subsequently involved in the most common age-related diseases (ARDs), as well as mesenchymal stem cells (MSCs) with an impairment of their properties in tissues regeneration. Endothelial cells seem to be able to exert a paracrine effect on BM-MSCs through the secretion of pro-inflammatory factors. This work is aimed to evaluate if the senescent status of human umbilical vein endothelial cells (HUVECs) could affect bone marrow derived MSCs (BM-MSCs) proliferative ability and stemness. HUVECs were cultured until the senescence status. Young (passage 3) and senescent HUVECs (passage 13) were indirectly co-cultured with BM-MSCs for 8 days in order to evaluate the effect of their senescence status on proliferative ability and stemness of MSCs. The co-culture of senescent HUVECs with BM-MSCs was associated with a reduced proliferative ability of BM-MSCs, an enforced pro-inflammatory phenotype of BM-MSCs (increased synthesis of proinflammatory cytokines such as IL-6 and TNF-α) and an increased expression of miR-126a-3p, in association with a significant decrease of SOX2, a stemmness- associated gene, targeted by miR-126a-3p. A more general IPA analysis, revealed as miR-126a-3p also modulates the expression of IRS1, IRS2, IL6ST and PIK3R2, all targets that enforce the hypothesis that senescent endothelial cells may reduce the proliferative ability and the stemness phenotype of bone marrow-derived mesenchymal stem cells.

Secretomes from Mesenchymal Stem Cells against Acute Kidney Injury: Possible Heterogeneity

A kidney has the ability to regenerate itself after a variety of renal injuries. Mesenchymal stem cells (MSCs) have been shown to ameliorate tissue damages during renal injuries and diseases. The regenerations induced by MSCs are primarily mediated by the paracrine release of soluble factors and extracellular vesicles, including exosomes and microvesicles. Extracellular vesicles contain proteins, microRNAs, and mRNAs that are transferred into recipient cells to induce several repair signaling pathways. Over the past few decades, many studies identified trophic factors from MSCs, which attenuate renal injury in a variety of animal acute kidney injury models, including renal ischemia-reperfusion injury and drug-induced renal injury, using microarray and proteomic analysis. Nevertheless, these studies have revealed the heterogeneity of trophic factors from MSCs that depend on the cell origins and different stimuli including hypoxia, inflammatory stimuli, and aging. In this review article, we summarize the secretomes and regenerative mechanisms induced by MSCs and highlight the possible heterogeneity of trophic factors from different types of MSC and different circumstances for renal regeneration.

Mesenchymal Stem Cells from Cervix and Age: New Insights into CIN Regression Rate

Cervical intraepithelial neoplasia (CIN) is a precancerous lesion of the uterine cervix that can regress or progress to cervical cancer; interestingly, it has been noted that young women generally seem to have higher rates of spontaneous regression and remission, suggesting a correlation between the patient's age and regression/progression rates of CIN. Even if the underlying mechanisms are still unclear, inflammation seems to play a pivotal role in CIN fate and inflammatory processes are often driven by mesenchymal stem cells (MSCs). This study was aimed at evaluating if age affects the behavior of MSCs from the cervix (C-MSCs) that in turn may modulate inflammation and, finally, regression rate. Fourteen samples of the human cervix were recovered from two groups of patients, "young" (mean age 28 ± 2) and "old" (mean age 45 ± 3), during treatment using the loop electrosurgical excision procedure (LEEP) technique. Progenitor cells were isolated, deeply characterized, and divided into young (yC-MSCs) and old cervixes (oC-MSCs); the senescence, expression/secretion of selected cytokines related to inflammation, and the effects of indirect cocultures with HeLa cells were analyzed. Our results show that isolated cells satisfy the fixed criteria for stemness and display age-related properties; yC-MSCs express a higher level of cytokines related to acute inflammation than oC-MSCs. Finally, in the crosstalk with HeLa cells, MSCs derived from the cervixes of young patients play a stronger antitumoral role than oC-MSCs. In conclusion, the immunobiology of MSCs derived from the cervix is affected by the age of donors and this can correlate with the regression rate of CIN by influencing their paracrine effect. In addition, MSCs from a young cervix drives an antitumoral effect by sustaining an acute inflammatory environment.

The Impact of Epigenetic Signatures on Amniotic Fluid Stem Cell Fate

Epigenetic modifications play a significant role in determining the fate of stem cells and in directing the differentiation into multiple lineages. Current evidence indicates that mechanisms involved in chromatin regulation are essential for maintaining stable cell identities. There is a tight correlation among DNA methylation, histone modifications, and small noncoding RNAs during the epigenetic control of stem cells' differentiation; however, to date, the precise mechanism is still not clear. In this context, amniotic fluid stem cells (AFSCs) represent an interesting model due to their unique features and the possible advantages of their use in regenerative medicine. Recent studies have elucidated epigenetic profiles involved in AFSCs' lineage commitment and differentiation. In order to use these cells effectively for therapeutic purposes, it is necessary to understand the basis of multiple-lineage potential and elaborate in detail how cell fate decisions are made and memorized. The present review summarizes the most recent findings on epigenetic mechanisms of AFSCs with a focus on DNA methylation, histone modifications, and microRNAs (miRNAs) and addresses how their unique signatures contribute to lineage-specific differentiation.

Breast Implant Texturization Does Not Affect the Crosstalk Between MSC and ALCL Cells

In the last decade, there has been a growing interest about the possible association between anaplastic large cell lymphoma (ALCL) and breast implants (BIA-ALCL). Many variables, such as breast implants texturization, have been investigated. Breast implants often lead to the formation of a periprosthetic capsule, characterized by inflammation. The presence of the inflamed capsule has been found in the majority of patients with BIA-ALCL. Inflammation may be sustained or counteracted by mesenchymal stem cells (MSCs) by the secretion of pro- or anti-inflammatory cytokines. MSCs were isolated from three capsules surrounding micro-textured (micro-MSCs) and from three capsules surrounding macro-textured (macro-MSCs) implants; after characterization, MSCs were co-cultured with KI-JK cells (a cell line derived from the cutaneous form of ALCL). The secretion of cytokines related to inflammation, the proliferation rate, and the expression of genes referred to pro-tumoral mechanisms were evaluated. Co-cultures of KI-JK cells with micro- or macro-MSCs gave the same results about the secretion of cytokines (increase of IL10, G-CSF, and TGF-β1 and decrease of IL4, IL5, IL12, IL13, IL17A, IFN-γ (p < 0.05) with respect to mock sample), expression of selected genes (increase for ACVR1, VEGF, TGF-βR2, CXCL12, and MKi67 (p < 0.05) with respect to control sample), and the proliferation rate (no variation between mock and co-cultured samples). Our results suggest that MSCs derived from capsules surrounding micro- and macro-textured implants display the same effects on the ALCL cells.

Effects of somatostatin and its analogues on progenitor mesenchymal cells isolated from human pituitary adenomas

PURPOSE

Progenitor mesenchymal cells (PMCs) have been found also in epithelial tumors and may derive from cancer stem cells (CSCs) by EMT mechanism. In this scenario, the effects of traditionally drugs on PMCs become of primary concern for therapeutic approaches. Previously, we isolated PMCs from acromegalic (GHomas) and not-functioning pituitary adenomas (NFPAs). Here we evaluate: (1) the role of EMT on their origin; (2) the presence of the somatostatin receptors (SSTR1-5); (3) the effects of somatostatin (SST) and its analogues (SSAs) on PMCs proliferation, apoptosis and SSTR1-5 expression.

METHODS

PMCs were isolated from GHomas and NFPAs; the expression of E-CADHERIN and TGFβRII (referred to EMT), the expression of the SSTR1-5 as well as the proliferation and apoptosis were tested before and after drugs administration.

RESULTS

Results show a decrease of E-CADHERIN and an increase of TGFβRII, confirming an EMT involvement; SSTR1-5 are more expressed by PMCs from GHomas than from NFPAs. SST and SSAs administration does not affect cell proliferation and SSTR1-5 expression on PMCs from NFPAs while in PMCs from GHomas, cell proliferation showed a marked decrease and a corresponding increase in the expression of SSTR1-2. Apoptosis rate and EMT were not affected by drugs administration.

CONCLUSIONS

Results indicate as EMT may be related to the presence of PMCs on pituitary tumors; SSAs, currently used in the management of human GHomas, exert anti-proliferative effect also in PMCs that, because of their derivation from CSCs, may be a new meaningful target for drugs treatment.

Inflammation by Breast Implants and Adenocarcinoma: Not Always a Bad Company

BACKGROUND

Inflammation and tumor are now an inseparable binomial. Inflammation may also derive by the use of breast implants followed by the formation of a periprosthetic capsule. It is known that tumor cells, in an inflamed microenvironment, can profit by the paracrine effect exerted also by mesenchymal stem cells (MSCs). Here we evaluated the role of inflammation on the immunobiology of MSCs before and after cocultures with cells derived from breast adenocarcinoma.

METHODS

MSCs derived from both inflamed (I-MSCs) and control (C-MSCs) tissues were isolated and cocultured with MCF7 cells derived from breast adenocarcinoma. Before and after cocultures, the proliferation rate of MCF7 cells and the expression/secretion of cytokines related to inflammation were tested.

RESULTS

Before cocultures, higher levels of cytokine related to chronic inflammation were detected in I-MSCs than in C-MSCs. After cocultures with MCF7, C- and I-MSCs show a variation in cytokine production. In detail, IL-2, IL-4, IL-5, IL-10, IL-13, TGF-β and G-CSF were decreased, whereas IL-6, IL-12, IFN-γ, and IL-17 were oversecreted. Proliferation of MCF7 was significantly increased after cocultures with I-MSCs.

CONCLUSIONS

Inflammation at the site of origin of MSCs affects their immunobiology. Even if tumor cells increased their proliferation rate after cocultures with I-MSCs, the analysis of the cytokines, known to play a role in the interference of tumor cells with the host immune system, absolves completely the breast implants from the insult to enforce the risk of adenocarcinoma.

Comparative miRNA-Based Fingerprinting Reveals Biological Differences in Human Olfactory Mucosa- and Bone-Marrow-Derived Mesenchymal Stromal Cells

Previously we reported that nestin-positive human mesenchymal stromal cells (MSCs) derived from the olfactory mucosa (OM) enhanced CNS myelination in vitro to a greater extent than bone-marrow-derived MSCs (BM-MSCs). miRNA-based fingerprinting revealed the two MSCs were 64% homologous, with 26 miRNAs differentially expressed. We focused on miR-146a-5p and miR-140-5p due to their reported role in the regulation of chemokine production and myelination. The lower expression of miR-140-5p in OM-MSCs correlated with higher secretion of CXCL12 compared with BM-MSCs. Addition of CXCL12 and its pharmacological inhibitors to neural co-cultures supported these data. Studies on related miR-146a-5p targets demonstrated that OM-MSCs had lower levels of Toll-like receptors and secreted less pro-inflammatory cytokines, IL-6, IL-8, and CCL2. OM-MSCs polarized microglia to an anti-inflammatory phenotype, illustrating potential differences in their inflammatory response. Nestin-positive OM-MSCs could therefore offer a cell transplantation alternative for CNS repair, should these biological behaviors be translated in vivo.

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OM-MSCs share 64% miRNA homology to BM-MSCs and differentially express 26 miRNAs

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CXCL12 promotes CNS myelination and is negatively regulated by miR-140-5p in BM-MSCs

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miR-146a-5p negatively regulates IL-6, IL-8, TLR2, and TLR4 on OM-MSCs

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These properties make OM-MSCs a suitable candidate for transplant-mediated CNS repair

MSCs and inflammation: new insights into the potential association between ALCL and breast implants

Possible association between anaplastic large cell lymphoma (ALCL) and breast implants has been suggested. In this context, formation of the periprosthetic capsule has been reported as a cause of inflammation, which plays a key role in tumor onset. Tumors take advantage of inflammation to influence and interfere with the host immune response by secreting multiple factors, and their onset and survival is in turn affected by the paracrine effects from mesenchymal stem cells (MSCs). In this study, we tried to clarify how inflammation can modify the immunobiology and the exerted paracrine effect of MSCs. MSCs derived from both inflamed (I-MSCs) and control (C-MSCs) tissues were isolated and co-cultured with an ALCL cell line. Proliferation rate and the expression of selected cytokines were tested. I-MSCs secrete higher levels of cytokine related to chronic inflammation than C-MSCs. After co-cultures with KI-JK cells, C- and I-MSCs show the same variation in the cytokine expression, with an increase of IL2, IL4, IL5, IL10, IL13, TNF-α, TGF-β, and G-CSF. Proliferation of ALCL cells was not influenced by co-cultures. Our results state that (i) inflamed microenvironment affects the immunobiology of MSCs modifying the profile of the expressed cytokines, and (ii) the paracrine effects exerted by MSCs on ALCL cells are not influenced by inflammation. Moreover, it seems that ALCL cells are able to manipulate MSCs' immunoregulatory properties to evade the host immune control. Nevertheless, this ability is not associated with inflammation and the question about BIA-ALCL is not proved by our experiments.

Human amniotic epithelial stem cells promote wound healing by facilitating migration and proliferation of keratinocytes via ERK, JNK and AKT signaling pathways

Wound healing is a highly orchestrated physiological process consisting in a complex interaction of cellular and biochemical events. Human amniotic epithelial stem cells (HAESCs) have been shown to be an attractive resource for wound healing because they are primitive stem cells. However, the exact effects of amnion-derived stem cells on the migration or proliferation of keratinocytes and their potential mechanism are not fully understood. We have found that HAESCs accelerate the migration of keratinocytes and induce a remarkable increase in the activity of phospho-ERK, phospho-JNK, and phospho-AKT, the blockade of which by their specific inhibitors significantly inhibits migration induced by HAESC-conditioned medium (CM). Furthermore, the co-culture of keratinocytes with HAESCs up-regulates the expression levels of cell proliferation proteins Cyclin D1, Cyclin D3 and Mdm2. In vivo animal experiments have shown that HAESC-CM improves wound healing, whereas blockade with ERK, JNK and AKT inhibitors significantly impairs wound healing. Taken together, these results reveal, for the first time, that HAESCs promote wound healing by facilitating the migration and proliferation of keratinocytes via ERK, JNK and AKT signaling pathways and might be a potential therapy in skin wound healing.

New miRNAs network in human mesenchymal stem cells derived from skin and amniotic fluid

Mesenchymal stem cells (MSCs), isolated from different adult sources, have great appeal for therapeutic applications due to their simple isolation, extensive expansion potential, and high differentiative potential.In our previous studies we isolated MSCs form amniotic fluid (AF-MSCs) and skin (S-MSCs) and characterized them according to their phenotype, pluripotency, and mRNA/microRNAs (miRNAs) profiling using Card A from Life Technologies.Here, we enlarge the profiling of AF-MCSs and S-MSCs to the more recently discovered miRNAs (Card B by Life Technologies) to identify the miRNAs putative target genes and the relative signaling pathways. Card B, in fact, contains miRNAs whose role and target are not yet elucidated.The expression of the analyzed miRNAs is changing between S-MSCs and AF-MSCs, indicating that these two types of MSCs show differences potentially related to their source. Interestingly, the pathways targeted by the miRNAS deriving from Card B are the same found during the analysis of miRNAs from Card A.This result confirms the key role played by WNT and TGF-β pathways in stem cell fate, underlining as other miRNAs partially ignored up to now deserve to be reconsidered. In addition, this analysis allows including Adherens junction pathways among the mechanisms finely regulated in stem cell behavior.

Stem cell origin differently affects bone tissue engineering strategies

Bone tissue engineering approaches are encouraging for the improvement of conventional bone grafting technique drawbacks. Thanks to their self-renewal and multi-lineage differentiation ability, stem cells are one of the major actors in tissue engineering approaches, and among these adult mesenchymal stem cells (MSCs) hold a great promise for regenerative medicine strategies. Bone marrow MSCs (BM-MSCs) are the first- identified and well-recognized stem cell population used in bone tissue engineering. Nevertheless, several factors hamper BM-MSC clinical application and subsequently, new stem cell sources have been investigated for these purposes. The fruitful selection and combination of tissue engineered scaffold, progenitor cells, and physiologic signaling molecules allowed the surgeon to reconstruct the missing natural tissue. On the basis of these considerations, we analyzed the capability of two different scaffolds, planned for osteochondral tissue regeneration, to modulate differentiation of adult stem cells of dissimilar local sources (i.e., periodontal ligament, maxillary periosteum) as well as adipose-derived stem cells (ASCs), in view of possible craniofacial tissue engineering strategies. We demonstrated that cells are differently committed toward the osteoblastic phenotype and therefore, taking into account their specific features, they could be intriguing cell sources in different stem cell-based bone/periodontal tissue regeneration approaches.

Comparative study between amniotic-fluid mesenchymal stem cells and retinal pigmented epithelium (RPE) stem cells ability to differentiate towards RPE cells

Dysfunction of the retinal pigmented epithelium (RPE) is one of the first effects of dry age-related macular degeneration (AMD) with consequent blindness. Hence, patients affected by this retinal disorder could benefit from a cell-based transplantation strategy for RPE. Actually, an effective protocol to approach this problem is lacking, though recently, it has been postulated the existence of a subpopulation of RPE stem cells (RPESCs) derived from adult RPE and able to reconstitute a functional RPE. On the other hand, the evidence related to the differentiative potential of human mesenchymal stem cells (MSCs) is continuously increasing. Among others, amniotic fluid-derived MSCs (AF-MSCs) may be a promising candidate, since these cells are characterized by high proliferation and differentiative potential. In this study, AF-MSCs and RPESCs were isolated, characterized to assay their stemness and induced to neuronal/retinal differentiation; specific RPE markers were then analyzed. Our results indicate that RPESCs are more suitable candidates for RPE replacement than AF-MSCs.

Isolation and characterization of progenitor mesenchymal cells in human pituitary tumors

The Cancer Stem Cells (CSCs) theory suggests that genetic alterations in stem cells are the direct cause for cancer. The evidence for a CSC population that results in pituitary tumors is poor. Some studies report the isolation of CSCs, but a deep characterization of the stemness of these cells is lacking. Here, we report the isolation and detailed characterization of progenitor mesenchymal cells (PMCs) from both growth hormone-secreting (GH(+)) and non-secreting (NS) pituitary adenomas, determining the immunophenotype, the expression of genes related to stemness or to pituitary hormone cell types, and the differentiative potential towards osteo-, chondro- and adipogenic lineages. Finally, the expression of CD133, known as a marker for CSCs in other tumors, was analyzed. Isolated cells, both from GH(+) and NS tumors, satisfy all the criteria for the identification of PMCs and express known stem cell markers (OCT4, SOX2, KLF4, NANOG), but do not express markers of pituitary hormone cell types (PITX2, PROP1, PIT1). Finally, PMCs express CD133. We demonstrated that pituitary tumors contain a stem cell population that can generate cell types characteristic of mesenchymal stem cells, and express CD133, which is associated with CSCs in other tumors.

Expression of neural markers by undifferentiated mesenchymal-like stem cells from different sources

The spontaneous expression of neural markers, already demonstrated in bone marrow (BM) mesenchymal stem cells (MSCs), has been considered as evidence of the MSCs' predisposition to differentiate toward neural lineages, supporting their use in stem cell-based therapy for neural repair. In this study we have evaluated, by immunocytochemistry, immunoblotting, and flow cytometry experiments, the expression of neural markers in undifferentiated MSCs from different sources: human adipose stem cells (hASCs), human skin-derived mesenchymal stem cells (hS-MSCs), human periodontal ligament stem cells (hPDLSCs,) and human dental pulp stem cells (hDPSCs). Our results demonstrate that the neuronal markers βIII-tubulin and NeuN, unlike other evaluated markers, are spontaneously expressed by a very high percentage of undifferentiated hASCs, hS-MSCs, hPDLSCs, and hDPSCs. Conversely, the neural progenitor marker nestin is expressed only by a high percentage of undifferentiated hPDLSCs and hDPSCs. Our results suggest that the expression of βIII-tubulin and NeuN could be a common feature of stem cells and not exclusive to neuronal cells. This could result in a reassessment of the use of βIII-tubulin and NeuN as the only evidence proving neuronal differentiation. Further studies will be necessary to elucidate the relevance of the spontaneous expression of these markers in stem cells.