IL-11 and soluble VCAM-1 are important components of Hypoxia Conditioned Media and crucial for Mesenchymal Stromal Cells attraction

Recombinant Human Bone Morphogenetic Protein-2 Priming of Mesenchymal Stem Cells Ameliorate Acute Lung Injury by Inducing Regulatory T Cells

Mesenchymal stromal/stem cells (MSCs) possess immunoregulatory properties and their regulatory functions represent a potential therapy for acute lung injury (ALI). However, uncertainties remain with respect to defining MSCs-derived immunomodulatory pathways. Therefore, this study aimed to investigate the mechanism underlying the enhanced effect of human recombinant bone morphogenic protein-2 (rhBMP-2) primed ES-MSCs (MSCBMP2) in promoting Tregs in ALI mice. MSC were preconditioned with 100 ng/ml rhBMP-2 for 24 h, and then administrated to mice by intravenous injection after intratracheal injection of 1 mg/kg LPS. Treating MSCs with rhBMP-2 significantly increased cellular proliferation and migration, and cytokines array reveled that cytokines release by MSCBMP2 were associated with migration and growth. MSCBMP2 ameliorated LPS induced lung injury and reduced myeloperoxidase activity and permeability in mice exposed to LPS. Levels of inducible nitric oxide synthase were decreased while levels of total glutathione and superoxide dismutase activity were further increased via inhibition of phosphorylated STAT1 in ALI mice treated with MSCBMP2. MSCBMP2 treatment increased the protein level of IDO1, indicating an increase in Treg cells, and Foxp3+CD25+ Treg of CD4+ cells were further increased in ALI mice treated with MSCBMP2. In co-culture assays with MSCs and RAW264.7 cells, the protein level of IDO1 was further induced in MSCBMP2. Additionally, cytokine release of IL-10 was enhanced while both IL-6 and TNF-α were further inhibited. In conclusion, these findings suggest that MSCBMP2 has therapeutic potential to reduce massive inflammation of respiratory diseases by promoting Treg cells.

Treatment of critical bone defects using calcium phosphate cement and mesoporous bioactive glass providing spatiotemporal drug delivery

Calcium phosphate cements (CPC) are currently widely used bone replacement materials with excellent bioactivity, but have considerable disadvantages like slow degradation. For critical-sized defects, however, an improved degradation is essential to match the tissue regeneration, especially in younger patients who are still growing. We demonstrate that a combination of CPC with mesoporous bioactive glass (MBG) particles led to an enhanced degradation in vitro and in a critical alveolar cleft defect in rats. Additionally, to support new bone formation the MBG was functionalized with hypoxia conditioned medium (HCM) derived from rat bone marrow stromal cells. HCM-functionalized scaffolds showed an improved cell proliferation and the highest formation of new bone volume. This highly flexible material system together with the drug delivery capacity is adaptable to patient specific needs and has great potential for clinical translation.

Comprehensive analysis on subchondral bone marrow lesions of human osteoarthritis by integrating bulk and single-cell transcriptomes

OBJECTIVE

This study aims to demonstrate the cellular composition and underlying mechanisms in subchondral bone marrow lesions (BMLs) of knee osteoarthritis (OA).

METHODS

BMLs were assessed by MRI Osteoarthritis Knee Score (MOAKS)≥2. Bulk RNA-sequencing (bulk-seq) and BML-specific differentially expressed genes (DEGs) analysis were performed among subchondral bone samples (including OA-BML=3, paired OA-NBML=3; non-OA=3). The hub genes of BMLs were identified by verifying in independent datasets and multiple bioinformatic analyses. To further estimate cell-type composition of subchondral bone, we utilized two newly developed deconvolution algorithms (MuSiC, MCP-counter) in transcriptomic datasets, based on signatures from open-accessed single-cell RNA sequencing (scRNA-seq). Finally, competing endogenous RNA (ceRNA) and transcription factor (TF) networks were constructed through multiple predictive databases, and validated by public non-coding RNA profiles.

RESULTS

A total of 86 BML-specific DEGs (up 79, down 7) were identified. IL11 and VCAN were identified as core hub genes. The "has-miR-424-5p/lncRNA PVT1" was determined as crucial network, targeting IL11 and VCAN, respectively. More importantly, two deconvolution algorithms produced approximate estimations of cell-type composition, and the cluster of heterotopic-chondrocyte was discovered abundant in BMLs, and positively correlated with the expression of hub genes.

CONCLUSION

IL11 and VCAN were identified as the core hub genes of BMLs, and their molecular networks were determined as well. We profiled the characteristics of subchondral bone at single-cell level and determined that the heterotopic-chondrocyte was abundant in BMLs and was closely linked to IL11 and VCAN. Our study may provide new insights into the microenvironment and pathological molecular mechanism of BMLs, and could lead to novel therapeutic strategies.

Combined application of BMP-2 and naturally occurring bioactive factor mixtures for the optimized therapy of segmental bone defects

Critical bone defects are the result of traumatic, infection- or tumor-induced segmental bone loss and represent a therapeutic problem that has not been solved by current reconstructive or regenerative strategies yet. Scaffolds functionalized with naturally occurring bioactive factor mixtures show a promising chemotactic and angiogenic potential in vitro and therefore might stimulate bone regeneration in vivo. To assess this prospect, the study targets at heparin-modified mineralized collagen scaffolds functionalized with naturally occurring bioactive factor mixtures and/or rhBMP-2. These scaffolds were implanted into a 2-mm segmental femoral defect in mice and analyzed in respect to newly formed bone volume (BV) and bone mineral density (BMD) by micro-computed tomography scans after an observation period of 6 weeks. To rate the degree of defect healing, the number of vessels, and the activity of osteoclasts and osteoblasts were analyzed histologically. The sole application of bioactive factor mixtures is inferior to the use of the recombinant growth factor rhBMP-2 regarding BV and degree of defect healing. A higher rhBMP-2 concentration or the combination with bioactive factor mixtures does not lead to a further enhancement in defect healing. Possibly, a synergistic effect can be achieved by further concentration or a prolonged release of bioactive factor mixtures. STATEMENT OF SIGNIFICANCE: The successful therapy of extended bone defects is still a major challenge in clinical routine. In this study we investigated the bone regenerative potential of naturally occuring bioactive factor mixtures derived from platelet concentrates, adipose tissue and cell secretomes as a cheap and promising alternative to recombinant growth factors in a murine segmental bone defect model. The mixtures alone were not able to induce complete bridging of the bone defect, but in combination with bone morphogenetic protein 2 bone healing seemed to be more physiological. The results show that naturally occuring bioactive factor mixtures are a promising add-on in a clinical setting.

VCAM-1 and GFPT-2: Predictive markers of osteoblast differentiation in human dental pulp stem cells

INTRODUCTION

Dental pulp stem cells (DPSCs) have high proliferative and multilineage differentiation potential in mesenchymal stem cells. However, several studies have indicated that there are individual differences in the potential for osteogenic differentiation of DPSCs, and the factors determining these differences are unknown.

OBJECTIVE

To identify the genes responsible for the individual differences in the osteogenic differentiation ability of DPSCs.

METHODS

We divided DPSCs into high and low osteogenic differentiation ability groups (HG or LG) with ALP and von Kossa stain, and compared the gene expression patterns using RNA-seq. In addition, genes that may affect osteogenic differentiation were knocked down using small interfering RNA (siRNA) and their effects were investigated.

RESULTS

The RNA-seq patterns revealed that VCAM1 and GFPT2 were significantly expressed at higher levels in the HG than in the LG. The results of siRNA analysis showed that VCAM1 and GFPT2 knockdown significantly reduced the expression of osteogenic markers. Furthermore, we analyzed the involvement of these two genes in cell signaling in DPSC differentiation. The results indicated that the VCAM1-mediated Ras-MEK-Erk and PI3K/Akt pathways are involved in the osteogenic differentiation of DPSCs, and that GFPT2-mediated HBP signaling influences the osteogenic differentiation of DPSCs.

CONCLUSIONS

These findings indicate that DPSCs that highly express VCAM1 and GFPT2 have a high capacity for osteogenic differentiation. Evaluation of VCAM1 and GFPT2 expression in undifferentiated DPSCs may predict the outcome of bone regenerative therapy using DPSCs. Moreover, the expression levels of VCAM1 and GFPT2 in DPSCs may be useful in setting criteria for selecting donors for allogeneic cell transplantation for bone regeneration.

Perturbations of mesenchymal stromal cells after allogeneic hematopoietic cell transplantation predispose for bone marrow graft-versus-host-disease

Functional impairment of the bone marrow (BM) niche has been suggested as a major reason for prolonged cytopenia and secondary graft failure after allogeneic hematopoietic cell transplantation (alloHCT). Because mesenchymal stromal cells (MSCs) serve as multipotent progenitors for several niche components in the BM, they might play a key role in this process. We used collagenase digested trephine biopsies to directly quantify MSCs in 73 patients before (n = 18) and/or after alloHCT (n = 65). For the first time, we demonstrate that acute graft-versus-host disease (aGvHD, n = 39) is associated with a significant decrease in MSC numbers. MSC reduction can be observed even before the clinical onset of aGvHD (n = 10). Assessing MSCs instantly after biopsy collection revealed phenotypic and functional differences depending on the occurrence of aGvHD. These differences vanished during ex vivo expansion. The MSC endotypes observed revealed an enhanced population of donor-derived classical dendritic cells type 1 and alloreactive T cells as the causing agent for compartmental inflammation and MSC damage before clinical onset of aGvHD was ascertained. In conclusion, MSCs endotypes may constitute a predisposing conductor of alloreactivity after alloHCT preceding the clinical diagnosis of aGvHD.

Strategies to improve the effect of mesenchymal stem cell therapy on inflammatory bowel disease

Inflammatory bowel disease (IBD) includes Crohn’s disease and ulcerative colitis and is an idiopathic, chronic inflammatory disease of the colonic mucosa. The occurrence of IBD, causes irreversible damage to the colon and increases the risk of carcinoma. The routine clinical treatment of IBD includes drug treatment, endoscopic treatment and surgery. The vast majority of patients are treated with drugs and biological agents, but the complete cure of IBD is difficult. Mesenchymal stem cells (MSCs) have become a new type of cell therapy for the treatment of IBD due to their immunomodulatory and nutritional functions, which have been confirmed in many clinical trials. This review discusses some potential mechanisms of MSCs in the treatment of IBD, summarizes the experimental results, and provides new insights to enhance the therapeutic effects of MSCs in future applications.

Human Umbilical Cord-Derived Mesenchymal Stem Cells Ameliorate Skin Aging of Nude Mice Through Autophagy-Mediated Anti-Senescent Mechanism

Skin aging is a currently irreversible process, affected by increased oxidative stress, activated cellular senescence, and lacked regeneration of the dermal layer. Mesenchymal stem cells (MSCs), such as human umbilical cord-derived MSCs (hucMSCs), have pro-regeneration and anti-aging potencies. To explore whether hucMSCs can be used to treat skin aging, this study employed skin-aging model of nude mice to conduct in vivo assays, including biochemical analysis of superoxide dismutase (SOD) and malondialdehyde (MDA), gross observation, histopathological observation, and immunohistochemical analysis. To clarify how hucMSCs work on skin aging, this study employed skin-aging model of human dermal fibroblasts (HDFs) to conduct in vitro assays by applying conditional medium of hucMSCs (CMM), including wound healing assay, senescence staining, flow cytometric oxidative detection, real time PCR, and western blot analysis. The in vivo data demonstrated that hucMSCs dose-dependently removed wrinkles, smoothed skin texture, and increased dermal thickness and collagen production of aged skin by reversing SOD and MDA levels and up-regulating Col-1 and VEGF expressions, indicating anti-oxidative and pro-regenerative effects against skin aging. The in vitro data revealed that hucMSCs significantly reversed the senescence of HDFs by promoting cell migration, inhibiting ROS production, and restoring the overexpressions of oxidative and senescent markers through paracrine mode of action, and the paracrine mechanism was mediated by the inhibition of autophagy. This study provided novel knowledge regarding the anti-aging efficacy and paracrine mechanism of hucMSCs on skin, making hucMSCs-based therapy a promising regime for skin aging treatment.

Effects of metformin on human bone-derived mesenchymal stromal cell-breast cancer cell line interactions

Metformin is used to treat patients with type 2 diabetes mellitus and was found to lower the incidence of cancer. Bone metastasis is a common impairment associated with advanced breast cancer. The present study investigated the effects of metformin on human bone-derived mesenchymal stromal cells (BM-MSC)—breast cancer cell line interactions. BM-MSCs grown from box chisels were tested for growth-stimulating and migration-controlling activity on four breast cancer cell lines either untreated or after pretreatment with metformin. Growth stimulation was tested in MTT tests and migration in scratch assays. Furthermore, the expression of adipokines of BM-MSCs in response to metformin was assessed using Western blot arrays. Compared to breast cancer cell lines (3.6 ± 1.4% reduction of proliferation), 500 µM metformin significantly inhibited the proliferation of BM-MSC lines (mean 12.3 ± 2.2 reduction). Pretreatment of BM-MSCs with metformin showed variable effects of the resulting conditioned media (CM) on breast cancer cell lines depending on the specific BM-MSC—cancer line combination. Metformin significantly reduced the migration of breast cancer cell lines MDA-MB-231 and MDA-MB-436 in response to CM of drug-pretreated BM-MSCs. Assessment of metformin-induced alterations in the expression of adipokines by BM-MSC CM indicated increased osteogenic signaling and possibly impairment of metastasis. In conclusion, the anticancer activities of metformin are the result of a range of direct and indirect mechanisms that lower tumor proliferation and progression. A lower metformin-induced protumor activity of BM-MSCs in the bone microenvironment seem to contribute to the positive effects of the drug in selected breast cancer patients.

The beneficial effect of Alpha-lipoic acid supplementation as a potential adjunct treatment in episodic migraines

The current study was performed to evaluate the effects of alpha-lipoic acid (ALA) supplementation on lactate, nitric oxide (NO), vascular cell adhesion molecule-1 (VCAM-1) levels, and clinical symptoms in women with episodic migraines. Considering the inclusion and exclusion criteria, ninety-two women with episodic migraines participated in this randomized, double-blind, placebo-controlled, parallel-design trial. The participants were randomly assigned to receive either 300 mg/day ALA or placebo, twice per day for 12 weeks. The primary outcomes included headache severity, headache frequency per month, and duration of attacks and the secondary outcomes included lactate (a marker of mitochondrial function), NO, and VCAM-1 serum levels were measured at baseline and the end of the intervention. At the end of the study, there was a significant decrease in lactate serum levels (- 6.45 ± 0.82 mg/dl vs - 2.27 ± 1.17 mg/dl; P = 0.039) and VCAM-1 (- 2.02 ± 0.30 ng/ml vs - 1.21 ± 0.36 ng/ml; P = 0.025) in the ALA as compared to the placebo group. In addition, the severity (P < 0.001), frequency (P = 0.001), headache impact test (HIT-6) (P < 0.001), headache dairy results (HDR) (P = 0.003), and migraine headache index score (MHIS) (P < 0.001) had significantly decreased in the intervention as compared to the control group. No significant changes were observed for NO levels and duration of migraine pains. ALA supplementation can be considered a potential adjunct treatment in patients with migraine due to its improving mitochondrial and endothelial functions and clinical symptoms.

Comparative Proteomic Analysis of the Mesenchymal Stem Cells Secretome from Adipose, Bone Marrow, Placenta and Wharton's Jelly

Mesenchymal stem cells (MSCs) have the potential to be a viable therapy against various diseases due to their paracrine effects, such as secretion of immunomodulatory, trophic and protective factors. These cells are known to be distributed within various organs and tissues. Although they possess the same characteristics, MSCs from different sources are believed to have different secretion potentials and patterns, which may influence their therapeutic effects in disease environments. We characterized the protein secretome of adipose (AD), bone marrow (BM), placenta (PL), and Wharton’s jelly (WJ)-derived human MSCs by using conditioned media and analyzing the secretome by mass spectrometry and follow-up bioinformatics. Each MSC secretome profile had distinct characteristics depending on the source. However, the functional analyses of the secretome from different sources showed that they share similar characteristics, such as cell migration and negative regulation of programmed cell death, even though differences in the composition of the secretome exist. This study shows that the secretome of fetal-derived MSCs, such as PL and WJ, had a more diverse composition than that of AD and BM-derived MSCs, and it was assumed that their therapeutic potential was greater because of these properties.