Retention of stemness and vasculogenic potential of human umbilical cord blood stem cells after repeated expansions on PES-nanofiber matrices

Nanofiber-expanded human CD34+ cells heal cutaneous wounds in streptozotocin-induced diabetic mice

Despite advances in diabetic wound care, the significant number of amputations that occur every year demands more effective therapeutics. Herein, we offer an aminated polyethersulfone nanofiber-expanded human umbilical cord blood-derived CD34⁺ cells (henceforth CD34⁺ cells) effective therapy, tested in cutaneous wounds developed in streptozotocin-induced diabetic NOD/SCID mice. We show that systemic administration of CD34⁺ cells homed to the wound site and significantly accelerated wound closure. Wound closure was associated with improved re-epithelialization and increased neovascularization; and with decreased sustained pro-inflammatory activity of NF-κB and its downstream effector molecules TNF-α, IL-1β, and IL-6 at the wound bed. This finding was further supported by the observation of a decreased number of myeloperoxidase positive neutrophils, and concomitantly increased levels of IL-10. In addition, improved granulation tissue formation was observed along with higher collagen deposition and myofibroblasts and decreased expressions of MMP-1. Mechanistically, CD34⁺ cells reduced the level of MMP-1 expression by inhibiting recruitment of NF-κB to the MMP-1 promoter site in dermal fibroblasts. In summary, we provide evidence of a novel nanofiber-expanded CD34⁺ stem cell therapeutic development for treating diabetic wounds by defining their cellular and molecular mechanisms.

Ferutinin directs dental pulp-derived stem cells towards the osteogenic lineage by epigenetically regulating canonical Wnt signaling

Osteoporosis is a silent systemic disease that causes bone deterioration, and affects over 10 million people in the US alone. This study was undertaken to develop a potential stem cell therapy for osteoporosis. We have isolated and expanded human dental pulp-derived stem cells (DPSCs), characterized them, and confirmed their multipotential differentiation abilities. Stem cells often remain quiescent and require activation to differentiate and function. Herein, we show that ferutinin activates DPSCs by modulating the Wnt/β-catenin signaling pathway and key osteoblast-secreted proteins osteocalcin and collagen 1A1 both mRNA and protein levels. To confirm that ferutinin modulates the Wnt pathway, we inhibited glycogen synthase kinase 3 (GSK3) and found that protein expression patterns were similar to those found in ferutinin-treated DPSCs. To evaluate the role of ferutinin in epigenetic regulation of canonical Wnt signaling, the pathway molecules Wnt3a and Dvl3 were analyzed using chromatin immunoprecipitation (ChIP)-quantitative PCR approaches. We confirmed that active marks of both H3K9 acetylation and H3K4 trimethylation were significantly enhanced in the promoter sites of the WNT3A and DVL3 genes in DPSCs after addition of ferutinin. These data provide evidence that ferutinin activates and promotes osteogenic differentiation of DPSCs, and could be used as an inducer as a potentially effective stem cell therapy for osteoporosis.

Current advances in ischemic stroke research and therapies

With more than 795,000 cases occurring every year, stroke has become a major problem in the United States across all demographics. Stroke is the leading cause of long-term disability and is the fifth leading cause of death in the US. Ischemic stroke represents 87% of total strokes in the US, and is currently the main focus of stroke research. This literature review examines the risk factors associated with ischemic stroke, changes in cell morphology and signaling in the brain after stroke, and the advantages and disadvantages of in vivo and in vitro ischemic stroke models. Classification systems for stroke etiology are also discussed briefly, as well as current ischemic stroke therapies and new therapeutic strategies that focus on the potential of stem cells to promote stroke recovery.