Skeletal Muscle Regeneration by the Exosomes of Adipose Tissue-Derived Mesenchymal Stem Cells.

Profound skeletal muscle loss can lead to severe disability and cosmetic deformities. Mesenchymal stem cell (MSC)-derived exosomes have shown potential as an effective therapeutic tool for tissue regeneration. This study aimed to determine the regenerative capacity of MSC-derived exosomes for skeletal muscle regeneration. Exosomes were isolated from human adipose tissue-derived MSCs (AD-MSCs). The effects of MSC-derived exosomes on satellite cells were investigated using cell viability, relevant genes, and protein analyses. Moreover, NOD-SCID mice were used and randomly assigned to the healthy control (n = 4), muscle defect (n = 6), and muscle defect + exosome (n = 6) groups. Muscle defects were created using a biopsy punch on the quadriceps of the hind limb. Four weeks after the surgery, the quadriceps muscles were harvested, weighed, and histologically analyzed. MSC-derived exosome treatment increased the proliferation and expression of myocyte-related genes, and immunofluorescence analysis for myogenin revealed a similar trend. Histologically, MSC-derived exosome-treated mice showed relatively preserved shapes and sizes of the muscle bundles. Immunohistochemical staining revealed greater expression of myogenin and myoblast determination protein 1 in the MSC-derived exosome-treated group. These results indicate that exosomes extracted from AD-MSCs have the therapeutic potential for skeletal muscle regeneration.

Therapeutic Effect of Pericytes for Diabetic Wound Healing.

Objective: Numerous attempts have been made to devise treatments for ischemic foot ulcer (IFU), which is one of the most severe and fatal consequences of diabetes mellitus (DM). Pericytes, which are perivascular multipotent cells, are of interest as a treatment option for IFU because they play a critical role in forming and repairing various tissues. In this study, we want to clarify the angiogenic potential of pericytes in DM-induced wounds. Methods: We evaluated pericyte stimulation capability for tube formation, angiogenesis, and wound healing (cell migration) in human umbilical vein endothelial cells (HUVECs) with in-vivo and in-vitro models of high glucose conditions. Results: When HUVECs were co-cultured with pericytes, their tube-forming capacity and cell migration were enhanced. Our diabetic mouse model showed that pericytes promote wound healing via increased vascularization. Conclusion: The findings of this study indicate that pericytes may enhance wound healing in high glucose conditions, consequently making pericyte transplantation suitable for treating IFUs.

De novo formation of citrate-based fluorophores on N-termini of peptides and proteins in cells and tissues.

We developed a new method for the de novo formation of fluorophores based on citrate (DNFC) in biological samples. Use of an amide coupling reagent and microwave irradiation greatly facilitates the fluorophore formation on peptides and proteins with N-terminal cysteine or serine. Since N-terminal cysteine and serine can form thiazolopyridone- or oxazolopyridone-based fluorophores emitting blue and green fluorescence, respectively, by the DNFC staining, each organelle, cell and tissue exhibited a characteristic fluorescence distribution. The DNFC staining is able to provide a new potential protocol for future cell imaging, histology and diagnosis.

Scalable and Isotropic Expansion of Tissues with Simply Tunable Expansion Ratio.

Tissue expansion techniques physically expand swellable gel-embedded biological specimens to overcome the resolution limit of light microscopy. As the benefits of expansion come at the expense of signal concentration, imaging volume and time, and mechanical integrity of the sample, the optimal expansion ratio may widely differ depending on the experiment. However, existing expansion methods offer only fixed expansion ratios that cannot be easily adjusted to balance the gain and loss associated with expansion. Here, a hydrogel conversion-based expansion method is presented, that enables easy adjustment of the expansion ratio for individual needs, simply by changing the duration of a heating step. This method, termed ZOOM, isotropically expands samples up to eightfold in a single expansion process. ZOOM preserves biomolecules for post-processing labelings and supports multi-round expansion for the imaging of a single sample at multiple zoom factors. ZOOM can be flexibly and scalably applied to nanoscale imaging of diverse samples, ranging from cultured cells to thick tissues, as well as bacteria, exoskeletal Caenorhabditis elegans, and human brain samples.