Project description:Severe angiopathy has been postulated as a major driver for diabetes associated secondary complications. So far the knowledge on underlying mechanisms and thereon based therapeutic options to attenuate these pathologies are limited. Here we systematically administered ABCB5+ MSCs for the treatment of chronic non-healing diabetic wounds employing db/db mice, a type II diabetes model as their number markedly declined during diabetes. We found that administration of ABCB5+ MSCs markedly accelerates wound closure in diabetic db/db mice as opposed to the vehicle treated control group. Strikingly, administration of ABCB5+ MSCs at the edges of the diabetic wounds triggered considerable neoangiogenesis, most likely by the releasing a Ribonuclease angiogenin that was identified through secretome analysis of ABCB5+ MSCs. Interestingly, silencing of angiogenin in ABCB5+ MSCs significantly delayed wound closure in diabetic db/db mice indicating its key role in skin regeneration. Moreover, angiogenin also impacted the polarization of macrophages. The findings from this study will provide novel insight into the unique capacity of ABCB5+ MSCs to mount an adaptive response at the wound site with the delivery of angiogenic molecules holds significant promise for the therapy of non-healing diabetes foot ulcers, and other pathologies with impaired angiogenesis. The benefits for refined stem cell based therapies is virtually unlimited.
Project description:Severe angiopathy is a major driver for diabetes associated secondary complications. Knowledge on underlying mechanisms essential for advanced therapies to attenuate these pathologies is limited. Injection of ABCB5+ stromal precursors (SPs) at the edge of non-healing diabetic wounds in a murine db/db model, closely mirroring human type II diabetes, profoundly accelerates wound closure. Strikingly, enhanced angiogenesis was substantially enforced by the release of the ribonuclease angiogenin from ABCB5+ SPs. This compensates for the profoundly reduced angiogenin expression in non-treated murine and human chronic diabetic wounds. Silencing of angiogenin in ABCB5+ SPs prior to injection significantly reduced angiogenesis, reduced numbers of M2 macrophages and delayed wound closure in diabetic db/db mice implying an unprecedented key role for angiogenin in tissue regeneration in diabetes. These data hold significant promise for further refining SPs-based therapies of non-healing diabetic foot ulcers and other pathologies with impaired angiogenesis.
Project description:ABCB5 is marker for Limbal epithilal stem cells. A comparison between ABCB5+ versus ABCB5- cultured human limbal epithelial cells was carried out to evaluate the properties of the limbal stem cell ABCB5+ with a special focus on their role in inflammation and angiogenesis.
Project description:We analyzed, by HTA 2.0, the GBM cell lines LN-18, LN-229, and U-87 MG after fluoresence-activated cell sorting (FACS) into ABCB5+ and ABCB5- fractions. Poor prognosis associated with glioblastoma multiforme (GBM) results from tumor resistance to therapy and high rate of recurrence. Compelling evidence suggests this is driven by subpopulations of slow-proliferating cancer stem cells with tumor-initiating potential. ATP-binding cassette member B5 (ABCB5) has been identified as a molecular marker for distinct subsets of chemoresistant tumor-initiating cell populations in diverse human malignancies. In the current study, we examined the potential role of ABCB5 in growth and chemoresistance of GBM. We found ABCB5 to be preferentially expressed in clinical GBM tumors and co-expressed with the stem cell marker CD133 in subpopulations of human GBM cell lines U-87 MG, LN-18 and LN-229. Antibody-mediated functional ABCB5 blockade inhibited proliferation and survival of human GBM cells and sensitized them to temozolomide (TMZ)-induced apoptosis. Likewise, in an in vivo GBM xenograft study in immunodeficient mice, anti-ABCB5 monoclonal antibody treatment inhibited tumor growth and sensitized tumors to TMZ therapy. Mechanistically, we demonstrated that ABCB5 regulates cell cycle checkpoint molecules to revoke drug-induced G2-M arrest and augments drug-mediated cell death. Overall, our data establish ABCB5 as a marker of GBM chemoresistance and point to the potential of ABCB5 targeting in improvement of current GBM therapies.
Project description:Functional analysis of ABCB5 in A375 and G3361 melanoma cells, by comparing stably-transfected controls to ABCB5-shRNA-targeted cells. 12 samples total. Replicates n=3 for the following 4 groups: A375 pSUPER-retro-puro-Vector vs. A375 pSUPER-retro-puro-ABCB5-KD; G3361 pSUPER-retro-puro-shCNTRL vs. G3361 pSUPER-retro-puro-ABCB5-KD.
Project description:Here we report the beneficial effects of a newly identified dermal cell subpopulation expressing the ATP-binding cassette subfamily B member 5 (ABCB5) for the therapy of non-healing wounds. Local administration of dermal ABCB5+-derived MSCs attenuated macrophage-dominated inflammation and thereby accelerated healing of full-thickness excisional wounds in the iron overload mouse model mimicking the non-healing state of human venous leg ulcers. The observed beneficial effects were due to interleukin-1 receptor antagonist (IL-1RA) secreted by ABCB5+-derived MSCs, which dampened inflammation and shifted the prevalence of unrestrained pro-inflammatory M1 macrophages towards repair promoting anti-inflammatory M2 macrophages at the wound site. The beneficial anti-inflammatory effect of IL-1RA released from ABCB5+-derived MSCs on human wound macrophages was conserved in humanized NOD-scid IL2rγnull mice. In conclusion, human dermal ABCB5+ cells represent a novel, easy accessible and marker-enriched source of MSCs which holds substantial promise to successfully treat chronic non-healing wounds in humans.
Project description:Objective This study aims to investigate the effects of electroacupuncture on chronic wounds associated with diabetes, particularly focusing on its potential mechanisms for enhancing wound healing through the promotion of angiogenesis. While acupuncture has been shown to improve wound healing by enhancing blood supply and vascular regeneration, the therapeutic effects of electroacupuncture in diabetic chronic wounds have not been sufficiently addressed. Methods A diabetic skin ulcer mouse model was established for this study. The effects of electroacupuncture on wound healing were assessed through evaluation of skin healing rates, ELISA assays, and histopathological analyses. Additionally, a tissue transparency three-dimensional imaging technique was utilized to establish a vascular model of wounds on day 10, clarifying the impact of electroacupuncture on angiogenesis during the proliferation phase in diabetic mouse skin wound models. Proteomic analysis was conducted to identify potential targets and mechanisms by which electroacupuncture regulates diabetic wound healing, further validated by immunohistochemistry (IHC) and Western blotting (WB). Results The experimental results demonstrated that electroacupuncture significantly promotes wound healing in diabetic mice, reduces the levels of the pro-inflammatory cytokine IL-6 during the inflammatory phase, decreases inflammatory cell infiltration, and increases collagen synthesis. Proteomic analysis indicated that electroacupuncture may facilitate diabetic wound healing by enhancing endothelial cell proliferation and modulating angiogenic morphogenesis. Furthermore, electroacupuncture was shown to upregulate the expression of CXCL12 and its co-localization with CXCR4, while promoting the phosphorylation of PI3K and AKT, thereby enhancing the expression of VEGF and improving angiogenesis. Three-dimensional tissue transparency imaging provided comprehensive visual evidence of the angiogenic effects induced by electroacupuncture. Conclusion The findings of this study suggest that electroacupuncture activates the PI3K/AKT signaling pathway through the CXCL12/CXCR4 axis to promote vascular regeneration, thereby improving the healing process of diabetic skin wounds in mice.
Project description:Functional analysis of ABCB5 in A375 and G3361 melanoma cells, by comparing stably-transfected controls to ABCB5-shRNA-targeted cells.