The Role of Matrix Metalloproteinases In Influencing Stem Cell Behavior and Skeletal Muscle Healing

Stem cells are highly valued for their capacity to aid in the functional recovery of damaged or diseased tissue. They are defined by their remarkable ability to maintain their undifferentiated state through countless cycles of cell division and to differentiate into variable types of specialized cells. Since ethical controversy has hindered funding for embryonic stem cell research and induced pluripotent stem cells are in the initial stages of investigations, much research has been conducted using adult stem cells. The use of adult stem cells in clinical applications is gradually becoming a reality; however, the major limitation is the difficulty to isolate, purify and expand them in culture. Matrix metalloproteinases (MMPs) have been regarded as a group of zinc-endopeptidases that influence tissue remodeling by degrading constituents of the extracellular matrix to actively promote cell proliferation, migration, apoptosis and differentiation. They have been suggested to play important roles in the regeneration of amputated newt limbs by contributing to a population of undifferentiated stem cells, called a blastema, which is likely formed by cell dedifferentiation. The research presented here builds on previous work investigating the therapeutic use of MMP1. Investigations have demonstrated the ability of MMP1 to aid in the recovery of skeletal muscle tissue by degrading fibrous scar tissue to facilitate cell migration and differentiation. This work examines the potential of MMP1 in skeletal muscle healing to stimulate stem cell behavior by the expression of certain muscle stem cell markers and its impact on cell differentiation. In addition, stem cells derived from skeletal muscle tissue were investigated to thoroughly elucidate the effect of blocking MMP signaling. MMP inhibition using GM6001 was observed to negatively impact muscle stem cell migration, stem cell associated markers and their differentiation capacity thus indicating the key role of MMPs in muscle stem cell behavior

Regeneration of Soft Tissues Is Promoted by MMP1 Treatment after Digit Amputation in Mice

The ratio of matrix metalloproteinases (MMPs) to the tissue inhibitors of metalloproteinases (TIMPs) in wounded tissues strictly control the protease activity of MMPs, and therefore regulate the progress of wound closure, tissue regeneration and scar formation. Some amphibians (i.e. axolotl/newt) demonstrate complete regeneration of missing or wounded digits and even limbs; MMPs play a critical role during amphibian regeneration. Conversely, mammalian wound healing re-establishes tissue integrity, but at the expense of scar tissue formation. The differences between amphibian regeneration and mammalian wound healing can be attributed to the greater ratio of MMPs to TIMPs in amphibian tissue. Previous studies have demonstrated the ability of MMP1 to effectively promote skeletal muscle regeneration by favoring extracellular matrix (ECM) remodeling to enhance cell proliferation and migration. In this study, MMP1 was administered to the digits amputated at the mid-second phalanx of adult mice to observe its effect on digit regeneration. Results indicated that the regeneration of soft tissue and the rate of wound closure were significantly improved by MMP1 administration, but the elongation of the skeletal tissue was insignificantly affected. During digit regeneration, more mutipotent progenitor cells, capillary vasculature and neuromuscular-related tissues were observed in MMP1 treated tissues; moreover, there was less fibrotic tissue formed in treated digits. In summary, MMP1 was found to be effective in promoting wound healing in amputated digits of adult mice. © 2013 Mu et al

MicroRNA expression in bone marrow-derived human multipotent Stromal cells

Abstract Background Multipotent stromal cells (MSCs) are being studied in the field of regenerative medicine for their multi-lineage differentiation and immunoregulatory capacity. MicroRNAs (miRNAs) are short non-coding RNAs that are responsible for regulating gene expression by targeting transcripts, which can impact MSC functions such as cellular proliferation, differentiation, migration and cell death. miRNAs are expressed in MSCs; however, the impact of miRNAs on cellular functions and donor variability is not well understood. Eight MSC lines were expanded to passages 3, 5 and 7, and their miRNA expression was evaluated using microarray technology. Results Statistical analyses of our data revealed that 71 miRNAs out of 939 examined were expressed by this set of MSC lines at all passages and the expression of 11 miRNAs were significantly different between passages 3 and 7, while the expression of 7 miRNAs was significantly different between passages 3 and 5. The expression of these identified miRNAs was evaluated using RT-qPCR for both the first set of MSC lines (n = 6) and a second set of MSC lines (n = 7) expanded from passages 4 to 8. By RT-qPCR only 2 miRNAs, miR-638 and miR-572 were upregulated at passage 7 compared to passage 3 in the first set of MSC lines by 1.71 and 1.54 fold, respectively; and upregulated at passage 8 compared to passage 4 in the second set of MSC lines, 1.35 and 1.59 fold, respectively. Conclusions The expression of miR-638 and miR-572 can distinguish MSCs from two different passages of cell culture. These results may be useful in establishing critical quality attributes of MSCs and determining whether changes in these two miRNAs impact cellular functions

Additional file 5: Table S3. of MicroRNA expression in bone marrow-derived human multipotent Stromal cells

Common miRNA Sequences Expressed by 8 Different Donors at Three Passages. (XLS 38 kb

Skeletal muscle-derived stem cells differentiate into hepatocyte-like cells and aid in liver regeneration

The liver is unique for its ability to regenerate after injury, however, critical injuries or disease cause it to lose this quality. Stem cells have been explored as a possibility to restore the function of seriously damaged livers, based on their self-renewability and multiple differentiation capacity. These experiments examine the ability of muscle derived stem cells (MDSCs) to differentiate into hepatocyte-like cells in vitro and acquire functional liver attributes for repairing damaged livers. In vitro experiments were performed using MDSCs from postnatal mice and mouse hepatocyte cell lines. Our data revealed that MDSCs differentiated into hepatocyte-like cells and expressed liver cell markers, albumin, hepatocyte nuclear factor 4α, and alpha feto-protein, both at the RNA and protein level. Additionally, in vivo studies showed successful engraftment of MDSCs into hepatectomized mouse livers of mice. These results provide evidence suggesting that MDSCs have the capacity to differentiate into liver cell-like cells and may serve as potential candidates to aid in liver regeneration

Additional file 4: Figure S1. of MicroRNA expression in bone marrow-derived human multipotent Stromal cells

Boxplots representing the miRNA signal distribution of the A) raw data; B) AFE-TGS normalized data; and C) quantile normalized data. Kernel density plots for the distribution of the D) within chip technical variability; and E) between chip technical variability for both AFE-TGS and quantile normalized data. Mean expression per miRNA sequence for the quantile normalized data versus the F) within chip technical variability; and G) between chip technical variability. (JPEG 816 kb

Additional file 6: Figure S2. of MicroRNA expression in bone marrow-derived human multipotent Stromal cells

The mean absolute difference between cancer and MSC expression of samples versus the technical variability cutoffs of A) within chip; and B) between chips. C) Signal distribution of the negative controls used to determine the background cutoff. (JPEG 674 kb

IL-13Rα2 gene expression is a biomarker of adverse outcome in patients with adrenocortical carcinoma.

Adrenocortical carcinoma (ACC) is a rare but aggressive endocrine malignancy that usually results in a fatal outcome. To allow the better clinical management and reduce mortality, we searched for clinical and molecular markers that are reliable predictor of disease severity and clinical outcome in ACC patients. We determined a correlation between the overexpression of IL-13Rα2 and the clinical outcome in ACC patients using comprehensive data available in The Cancer Genome Atlas (TCGA) database. The dataset of 79 ACC subjects were divided into groups of low, medium, or high expression of IL-13Rα2 as determined by RNA-seq. These patients were also stratified by length of survival, overall survival, incidence of a new tumor event, incidence of metastasis, and production of excess hormones. We report a correlation between IL-13Rα2 expression and survival of subjects with ACC. High expression of IL-13Rα2 in ACC tumors was significantly associated with a lower patient survival rate and period of survival compared to low expression (p = 0.0084). In addition, high IL-13Rα2 expression was significantly associated with a higher incidence of new tumor events and excess hormone production compared to low or medium IL-13Rα2 expression. Within the cohort of patients that produced excess hormone, elevated IL-13Rα2 expression was significantly associated with a lower survival rate. Additionally, IL-13Rα1 had a potential relationship between transcript level and ACC survival. Our results and promising antitumor activity in preclinical models and trials indicate that IL-13Rα2 expression is an important prognostic biomarker of ACC disease outcome and a promising target for therapeutic treatment of ACC

MMP1 treatment enhanced stem cell population.

<p>The localization of Sca-1 expressive cells at 10 days after amputation is compared between untreated (<b><i>Aa</i></b>) and MMP1 treated (<b><i>Bb</i></b>) regenerating digits. The number of expression of Sca-1 positive cells was enriched in MMP1 treated digits compared to non-treated digits, respectively (<b><i>C</i></b>). Arrows (red): Sca-1 positive cells; DAPI staining (blue): indicated cells’ nucleus. N = 4 for each group; *p<0.05 was considered as significant.</p

MMP1 treatment improved nerve regeneration and reduced fibrosis formation in the amputated digits.

<p>The localization of NCAM and dystrophin proteins in regenerating digits was compared between MMP1 treated and non-treated digits at day 25 (<b><i>A–D</i></b>). The sub-image in <b>D</b> shows the cross-section view of the nerve-related structure (<b><i>D</i></b><b>,</b> marked area with red squared line). Arrows: NCAM positive peripheral nerves (red); arrowheads: NCAM positive nerve-related structure (yellow). Dystrophin expression is shown in green and cell nucleus blue (DAPI). The level/position of sections in this comparison is demonstrated (<b>E</b>). NCAM expression in the amputated digits was significantly higher in MMP1 treated digits (<b>F</b>). To compare fibrosis formation in the differentially treated digits, trichrome staining was conducted with tissue sections of non-treated digits (<b><i>G&I</i></b>) and MMP1 treated digits (<b><i>H&J</i></b>). The level/position of sections in this comparison is demonstrated (<b>K</b>) and the quantification of fibrotic structure (collagen deposition in ECM) at day 25 shown (<b>L</b>). N = 4 for each group; *p<0.05 was considered as significant.</p