Bone marrow-derived mesenchymal stromal cell: what next?

Depletion of MicroRNA-100-5p Promotes Osteogenesis Via Lysine(K)-Specific Demethylase 6B

Senescence and osteogenic differentiation potential loss limited bone nonunion treatment effects of bone marrow-derived mesenchymal stem cells (BMSCs). MiR-100-5p/Lysine(K)-specific demethylase 6B (KDM6B) can inhibit osteogenesis, but their effects on bone union remain unclear. This study aims to investigate the effects of miR-100-5p/KDM6B on osteogenic differentiation and bone defects. Wild-type or microRNA 100 (miR-100) knockdown mice underwent critical-size defect (CSD) cranial surgery and collagen I/poly-γ-glutamic acid scaffold treatment. The crania was observed using microcomputed tomography, hematoxylin and eosin staining, Masson staining, alkaline phosphatase (ALP) staining, immunohistochemistry, and immunofluorescence. Primary-cultured BMSCs transfected with miR-100-5p mimic/inhibitor and KDM6B cDNA were evaluated for osteogenic differentiation using Alizarin Red staining, ALP activity detection, and Western blot analysis. Genetic transcription levels were detected using quantitative reverse transcription polymerase chain reaction. This study found that miR-100 depletion promotes defect healing in mouse calvaria, increases the proportion of new bone and osteoblasts in calvaria, and activates the expression of KDM6B and osteocalcin (OCN) proteins, promoting the transcription of bone morphogenetic protein-2, Runt-related transcription factor 2 (Runx2), OCN, and KDM6B, while methylation of lysine 27 on histone H3 (H3K27me3) decreased. Furthermore, miR-100-5p mimics suppressed osteogenic differentiation by inhibiting KDM6B with increased H3K27me3, ALP, Runx2, OCN, and osteopontin protein expression, while miR-100-5p inhibitors have opposite effects. Moreover, KDM6B can reverse miR-100-5p mimic effects. Notably, scaffolds carrying miR-100-5p mimics/inhibitors transfected BMSCs were placed in CSD mice and found that miR-100-5p inhibitors have a better effect on CSD healing and increase new bone without inflammatory cell infiltration. This study proved that miR-100-5p depletion promotes bone union and osteogenic differentiation of BMSCs via KDM6B/H3K27me3.

Mesenchymal Stromal Cells Nanovesicles Carry microRNA with Nephroprotective Proprieties Regardless of Aging

Containing information molecules from their parent cells and inclining to fuse with targeted cells, bone marrow mesenchymal stromal cells-derived extracellular vesicles (MSCs- EV) are valuable in nanomedicine.

BACKGROUND

The effects of aging on the paracrine mechanism and in the production and action of MSCs-EV and their cargos of miR-26a and siRNA-26a for the treatment of tubular renal cells under nephrotoxicity injury remain unelucidated.

OBJECTIVE

The purpose of this study was to evaluate MSCs-EV of different ages and their ability to deliver the cargos of miR-26a and siRNA-26a to target renal tubular cells affected by nephrotoxicity injury.

METHODS

In a model of gentamicin-induced nephrotoxicity, renal tubular cells treated with MSCs-EV expressing or not expressing microRNA-26a were analyzed. Western blotting was utilized to evaluate cell cycle markers, and MTT assay was utilized to evaluate auto-renovation capacity.

RESULTS

Tubular cells under nephrotoxicity injury showed decreased proliferative capacity, but the treatment in the tubular renal cells under nephrotoxicity injury with MSCs-EV expressing microRNA-26a showed nephroprotective effects, regardless of EV age. While the treatment with EV-mediated siRNA-26a failed to preserve the nephroprotective effects equally, regardless of age.

CONCLUSION

Mesenchymal stromal cell nanovesicles carry microRNA with nephroprotective proprieties regardless of aging.

Comparison of the biological and functional characteristics of mesenchymal stem cells from intrahepatic and identical bone marrow

In our privious work, our reseach group characterized a population of hepatic-sourced mesenchymal stem cells (MSCs) called MLpvNG2⁺ cells. In the present study, we compared the biological and functional characteristics of naïve MLpvNG2 cells with identical bone marrow-derived MSCs (niBM-MSCs) using in vitro (conditioned media) and in vivo (a well-set diethylnitrosamine (DEN)-induced liver fibrotic/cirrhotic murine model) procedures. The intrahepatic-sourced mesodermal MLpvNG2⁺ cells exhibited some biological characteristics (e.g., a set of surface markers) similar to those of extrahepatic niBM-MSCs. In responsed to signals of pathological conditions, such as singals of fibrotic/cirrhotic liver, MLpvNG2⁺ cells showed higher survival and favored differentiation into ALB(+) and G6Pc(+) hepatocytes, whereas niBM-MSCs predominantly differentiated into CK/KRT19(+) cholangiocytes. We identified C/EBPα/β expression as a biological characteristic differentiating these two populations of MSCs, wherein MLpvNG2⁺ cells are likely regulated by C/EBPβ transcriptional signaling, whereas niBM-MSCs are likely controlled by C/EBPα transcriptional signaling. Notably, although C/EBPα and C/EBPβ transcriptional signaling regulate hepatocyte and cholangiocyte fate, respectively, the expression of these proteins in MLpvNG2⁺ cells is, to our knowledge, reported for the first time in the present study. We used anti-C/EBP neutralizing antibodies (Abs) both in vitro and in vivo to determine the functional characteristics of these proteins. We conclude that the biological characteristics of these two populations of MSCs depend on their differential C/EBPα/β expression patterns.

Mesenchymal Stem Cells Application in Wound Tissue Healing in Old Animals

Purpose

An assessment of the effectiveness of progenitor mesenchymal stem cell as injections and as part of a polymer hydrogel for the wounds treatment.

Materials and Methods

Fixed-size wounds (average area of 135.8 mm²) were modeled on the back of white Wistar rats, aged 9 months. Mesenchymal stem cells (MSC) isolated from a human umbilical cord were injected into the wounds once on the modeling day (SC group). In other animals, MSC were periodically applied externally as one of the components in the polymer hydrogel (Polymer_sc group). The systemic effect of the cells was assessed via the analysis of intact contralateral wounds located on the opposite side of the same animal’s back (groups Control_sc and Control_Psc, respectively). The reference intact wounds belonged to the Control_0 group. The wound area was studied in dynamics. Descriptive microscopy was supplemented by an assessment of the collagen fibers’ maturity, the epidermal layers, and the number of fibroblasts and leukocytes in different parts of the wounds.

Results

Both the local and systemic application of MSC led to an improvement in wound regeneration. During the acute inflammatory phase (up to 3 days), the method and place of application did not affect the dynamics of wound healing. The use of Polymer_sc ultimately demonstrated the best effectiveness. The anti-inflammatory effect of MSC was confirmed by a decrease in leukocyte infiltration in the wound centers (Polymer_sc and SC groups) and edges (all groups, with the greatest extent in the Polymer_sc group). The proliferative phase that expresses itself via accelerated growth in fibroblast number and collagen production was affected in the Control_Psc group and mostly in the Polymer_sc group.

Conclusion

The applications of MSC in various ways improve and accelerate wound healing even in old animals. The best performance was achieved in the Polymer_sc group.

Paracrine Mechanisms of Mesenchymal Stromal Cells in Angiogenesis

The role of the mesenchymal stromal cell- (MSC-) derived secretome is becoming increasingly intriguing from a clinical perspective due to its ability to stimulate endogenous tissue repair processes as well as its effective regulation of the immune system, mimicking the therapeutic effects produced by the MSCs. The secretome is a composite product secreted by MSC in vitro (in conditioned medium) and in vivo (in the extracellular milieu), consisting of a protein soluble fraction (mostly growth factors and cytokines) and a vesicular component, extracellular vesicles (EVs), which transfer proteins, lipids, and genetic material. MSC-derived secretome differs based on the tissue from which the MSCs are isolated and under specific conditions (e.g., preconditioning or priming) suggesting that clinical applications should be tailored by choosing the tissue of origin and a priming regimen to specifically correct a given pathology. MSC-derived secretome mediates beneficial angiogenic effects in a variety of tissue injury-related diseases. This supports the current effort to develop cell-free therapeutic products that bring both clinical benefits (reduced immunogenicity, persistence in vivo, and no genotoxicity associated with long-term cell cultures) and manufacturing advantages (reduced costs, availability of large quantities of off-the-shelf products, and lower regulatory burden). In the present review, we aim to give a comprehensive picture of the numerous components of the secretome produced by MSCs derived from the most common tissue sources for clinical use (e.g., AT, BM, and CB). We focus on the factors involved in the complex regulation of angiogenic processes.

Stem cell treatment and cerebral palsy: Systemic review and meta-analysis

BACKGROUND

Perinatal complications may result in life-long morbidities, among which cerebral palsy (CP) is the most severe motor disability. Once developed, CP is a non-progressive disease with a prevalence of 1-2 per 1000 live births in developed countries. It demands an extensive and multidisciplinary care. Therefore, it is a challenge for our health system and a burden for patients and their families. Recently, stem cell therapy emerged as a promising treatment option and raised hope in patients and their families.

AIM

The aim is to evaluate the efficacy and safety of stem cell treatment in children with CP using a systematic review and meta-analysis

METHODS

We performed a systematic literature search on PubMed and EMBASE to find randomized controlled clinical trials (RCT) investigating the effect of stem cell transplantation in children with CP. After the review, we performed a random-effects meta-analysis focusing on the change in gross motor function, which was quantified using the gross motor function measure. We calculated the pooled standardized mean differences of the 6- and/or 12-mo-outcome by the method of Cohen. We quantified the heterogeneity using the I-squared measure.

RESULTS

We identified a total of 8 RCT for a qualitative review. From the initially selected trials, 5 met the criteria and were included in the meta-analysis. Patients’ population ranged from 0.5 up to 35 years (n = 282). We detected a significant improvement in the gross motor function with a pooled standard mean difference of 0.95 (95% confidence interval: 0.13-1.76) favoring the stem cell group and a high heterogeneity (I² = 90.1%). Serious adverse events were rare and equally distributed among both intervention and control groups.

CONCLUSION

Stem cell therapy for CP compared with symptomatic standard care only, shows a significant positive effect on the gross motor function, although the magnitude of the improvement is limited. Short-term safety is present and further high-quality RCTs are needed.

Hyaluronic Acid Hydrogel Integrated with Mesenchymal Stem Cell-Secretome to Treat Endometrial Injury in a Rat Model of Asherman's Syndrome

Stem cell therapies have made strides toward the efficacious treatment of injured endometrium and the prevention of intrauterine adhesions, or Asherman's syndrome (AS). Despite this progress, they are limited by their risk of tumor formation, low engraftment rates, as well as storage and transportation logistics. While attempts have been made to curb these issues, there remains a need for simple and effective solutions. A growing body of evidence supports the theory that delivering media, conditioned with mesenchymal stem cells, might be a promising alternative to live cell therapy. Mesenchymal stem cell-secretome (MSC-Sec) has a superior safety profile and can be stored without losing its regenerative properties. It is versatile enough to be added to a number of delivery vehicles that improve engraftment and control the release of the therapeutic. Thus, it holds great potential for the treatment of AS. Here, a new strategy for loading crosslinked hyaluronic acid gel (HA gel) with MSC-Sec is reported. The HA gel/MSC-Sec treatment paradigm creates a sustained release system that repairs endometrial injury in rats and promotes viable pregnancy.