Mesenchymal stem cells (MSCs) can differentiate not only into mesenchymal lineage cells but also into various other cell lineages. As MSCs can easily be isolated from bone marrow, they can be used in various tissue engineering strategies. In this study, we assessed whether MSCs can differentiate into multiple skin cell types including keratinocytes and contribute to wound repair. First, we found keratin 14-positive cells, presumed to be keratinocytes that transdifferentiated from MSCs in vitro. Next, we assessed whether MSCs can transdifferentiate into multiple skin cell types in vivo. At sites of mouse wounds that had been i.v. injected with MSCs derived from GFP transgenic mice, we detected GFP-positive cells associated with specific markers for keratinocytes, endothelial cells, and pericytes. Because MSCs are predominantly located in bone marrow, we investigated the main MSC recruitment mechanism. MSCs expressed several chemokine receptors; especially CCR7, which is a receptor of SLC/CCL21, that enhanced MSC migration. Finally, MSC-injected mice underwent rapid wound repaired. Furthermore, intradermal injection of SLC/CCL21 increased the migration of MSCs, which resulted in an even greater acceleration of wound repair. Taken together, we have demonstrated that MSCs contribute to wound repair via processes involving MSCs differentiation various cell components of the skin.

ABSTRACT

Angiogenesis, a process by which new vascular networks are formed from pre-existing capillaries, is required for tumors to grow, invade, and metastasize. Vascular endothelial growth factor (VEGF), a specific mitogen to endothelial cells, is a crucial factor for tumor angiogenesis. In this study, we investigated whether minodronate, a newly developed nitrogen-containing bisphosphonate, could inhibit melanoma growth and improve survival in nude mice by suppressing the VEGF signaling. We found here that minodronate inhibited melanoma growth and improved survival in nude mice by suppressing the tumor-associated angiogenesis and macrophage infiltration. Minodronate completely inhibited the VEGF-induced increase in DNA synthesis and tube formation in endothelial cells by suppressing NADPH oxidase-mediated reactive oxygen species generation and Ras activation. Furthermore, minodronate inhibited the VEGF-induced expression of intercellular adhesion molecule-1 and monocyte chemoattractant protein-1 in endothelial cells. Minodronate decreased DNA synthesis and increased apoptotic cell death of cultured melanoma cells as well. Our present study suggests that minodronate might suppress melanoma growth and improve survival in nude mice by two independent mechanisms; one is by blocking the VEGF signaling in endothelial cells, and the other is by inducing apoptotic cell death of melanoma. The present study provides a novel potential therapeutic strategy for the treatment of melanoma.

Attempts to treat congenital protein deficiencies using bone marrow-derived cells have been reported. These efforts have been based on the concepts of stem cell plasticity. However, it is considered more difficult to restore structural proteins than to restore secretory enzymes. This study aims to clarify whether bone marrow transplantation (BMT) treatment can rescue epidermolysis bullosa (EB) caused by defects in keratinocyte structural proteins. BMT treatment of adult collagen XVII (Col17) knockout mice induced donor-derived keratinocytes and Col17 expression associated with the recovery of hemidesmosomal structure and better skin manifestations, as well improving the survival rate. Both hematopoietic and mesenchymal stem cells have the potential to produce Col17 in the BMT treatment model. Furthermore, human cord blood CD34 + cells also differentiated into keratinocytes and expressed human skin component proteins in transplanted immunocompromised (NOD/SCID/γ c null ) mice. The current conventional BMT techniques have significant potential as a systemic therapeutic approach for the treatment of human EB.

Helicobacter cinaedi causes gastroenteritis and bacter-aemia, particularly in immunocompromised individuals. Although cellulitis is sometimes reported to accompany infection by this pathogen, the cutaneous manifestations are poorly understood. To clarify the characteristic cutaneous features, 47 cases of H. cinaedi bacteraemia experienced at Sapporo City General Hospital as nosocomial infection were retrospectively evaluated. Thirty-four percent (16 cases) of the patients showed cutaneous lesions. They all had sudden onset of erythemas accompanied by high temperature. The most common cutaneous manifestations were found to be superficial cellulitis, which results in painful erythemas or infiltrated erythematous plaques on the extremities. These skin lesions can be an early clinical indicator of H. cinaedi bacteraemia in the setting of nosocomial infection.