Umbilical cord blood mesenchymal stem cells protect amyloid-β42 neurotoxicity via paracrine

Figure 1 Decorin and progranulin are highly secreted from human umbilical cord blood-derived mesenchymal stem cells. A: Human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) were co-cultured with amyloid-β42-exposed rat primary neuronal cells for 24 h in a Transwell chamber. Then, rat primary neuronal cells were stained by Live/Dead staining. Green color indicates surviving neuronal cells. B: Percentage of dead cells was calculated (P < 0.05, n = 4 per group); C: To identify paracrine factors, co-cultured media was analyzed by antibody-based array (RayBio). Spot intensity of progranulin and decorin in co-cultured media was much higher compared to rat primary neuronal cells in the absence of hUCB-MSC (P < 0.05, n = 3 per group); D: Each medium used in the Transwell was analyzed by enzyme-linked immunosorbant assay for progranulin and decorin (^aP < 0.05, ^cP < 0.05, n = 3 per group).

Figure 2 Recombinant progranulin and decroin protect against amyloid-β42-neurotoxicity in vitro. A: Instead of human umbilical cord blood-derived mesenchymal stem cells, 10 ng of progranulin and decroin were used to treat amyloid-β42 (Aβ42)-exposed rat primary neuronal cells, After 36 h, each cell was assayed by Live/Dead staining. The green and red colorindicate live and dead cells, respectively; B: Percentage of dead cells in decroin- and progranulin-treated cells exposed to Aβ42; C: To show survived neurons in rat primary neuronal cells, cells were stained by anti-microtubule associated protein 2 antibody. PGRN: Progranulin; DCN: Decorin.

Figure 3 Knock-down of decorin and progranulin by siRNAs reduces the anti-apoptotic effect on human umbilical cord blood-derived mesenchymal stem cells in a Transwell chamber. A, B: Each siRNA was pretreated in human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSC) for 6 h. These cells were co-cultured with rat primary neuronal cells for 24 h. After co-culturing, the medium was analyzed by enzyme-linked immunosorbant assay for progranulin (A) (^aP < 0.05, n = 3 per group) and decorin (B) (^aP < 0.05, n = 3 per group); C: Rat primary neurons in each condition were stained by anti-microtubule associated protein 2 (MAP2) antibody. Red color indicates MAP2-positive neurons and nuclei were visualized by DAPI (blue); D: The percentage of MAP2-postive neuron in each conditions were analyzed (^aP < 0.05, n = 3 per group). CONT: Control; PGRN: Progranulin; DCN: Decorin.

Figure 4 Paracrine action of human umbilical cord blood-derived mesenchymal stem cells in amyloid-β42 neurotoxicity in vitro. We previously reported that human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) secrete soluble intercellular adhesion molecule-1 (sICAM-1) and galectin-3 for Aβ clearance and neuron survival, respectively. We also showed anti-apoptotic role of decorin and progranulin in amyloid-β42-neurotoxicity in vitro. Recently, MSCs have become regarded as drugable cells because they secrete various beneficial proteins for healing of damaged sites.