Neuroprotective and immunomodulatory properties of WJ-MSC cultured in 3D hydrogel scaffolds on postischemic organotypic hippocampal slices

Mesenchymal stem cells (MSC) exhibit neuroprotective, angiogenic and immunomodulatory properties. Their availability, high plasticity and possibility for expansion have made MSC-based therapy one of the most commonly used in regenerative medicine. In order to provide optimal microenvironment in vitro, 3D scaffolds were designed with structural and functional properties to protect transplanted cells from recipient immune system, as well as facilitate structural logistic for host transplant interaction. WJ-MSCs isolated from human umbilical cords were cultured under 21% O2 and 5% O2 conditions. The aim of in vitro study was to test the effect of different oxygen concentration and dimensional conditions on proliferation, viability and gene expression profile of WJ-MSC. In ex vivo studies an experimental model of oxygen glucose deprivation was used in order to mimic an ischemic injury. MSC-induced neuroprotection was evaluated after 24 h in OHC co-cultured with WJ-MSCs in 2D or 3D conditions. WJ-MSC from control (2D) and 3D scaffolds were characterized with qRT-PCR for the expression of growth factors and cytokines after 24 h of co-culture. WJ-MSCs have a linear growth rate and are able to migrate beyond the 3D hydrogel scaffolds structures. The increased expression of e.g. BDNF, GDNF, VEGF-A, bFGF as compared with 2D cultures has been observed. WJ-MSCs have shown a strong neuroprotective effect on injured hippocampal slices. Moreover, WJ-MSC cultured on 3D scaffolds revealed the increased expression of several neurotrophins (BDNF, NGF), growth factors (bFGF, EGF) and decreased expression of pro-inflammatory cytokines, e.g. IL-1β, together with higher expression of anti-inflammatory TGF-β. The results have indicated that different conditions of microenvironment (oxygen concentration and 3D scaffolds) affect analyzed stem cells properties. Moreover, the analyzed scaffold models, together with modulating oxygen level allow building up biomimetic conditions for in vitro stem cells culture and serving as a promising material for future use in MSC-based therapy.