Glutathione–Allylsulfur Conjugates as Mesenchymal Stem Cells Stimulating Agents for Potential Applications in Tissue Repair

Abstract

The endogenous gasotransmitter H2S plays an important role in the central nervous, respiratory and cardiovascular systems. Accordingly, slow-releasing H2S donors are powerful tools for basic studies and innovative pharmaco-therapeutic agents for cardiovascular and neurodegenerative diseases. Nonetheless, the effects of H2S-releasing agents on the growth of stem cells have not been fully investigated. H2S preconditioning can enhance mesenchymal stem cell survival after post-ischaemic myocardial implantation; therefore, stem cell therapy combined with H2S may be relevant in cell-based therapy for regenerative medicine. Here, we studied the effects of slow-releasing H2S agents on the cell growth and differentiation of cardiac Lin− Sca1+ human mesenchymal stem cells (cMSC) and on normal human dermal fibroblasts (NHDF). In particular, we investigated the effects of water-soluble GSH–garlic conjugates (GSGa) on cMSC compared to other H2S-releasing agents, such as Na2S and GYY4137. GSGa treatment of cMSC and NHDF increased their cell proliferation and migration in a concentration dependent manner with respect to the control. GSGa treatment promoted an upregulation of the expression of proteins involved in oxidative stress protection, cell–cell adhesion and commitment to differentiation. These results highlight the effects of H2S-natural donors as biochemical factors that promote MSC homing, increasing their safety profile and efficacy after transplantation, and the value of these donors in developing functional 3D-stem cell delivery systems for cardiac muscle tissue repair and regeneration.

Photo-Polymerization Damage Protection by Hydrogen Sulfide Donors for 3D-Cell Culture Systems Optimization

“…These data demonstrate that functionalized proteins which are a part of the hybrid hydrogel scaffold design can provide cell protection from the PhP damage acting as scavengers to free radicals. Having validated the TST assay to quantify oxidative damage associated with PhP, we next sought to measure the protective effects of a glutathione-conjugated garlic extract, named GSGa, which was able to provide a slow-release of H 2 S [ 30 , 49 ]. GSGa was added to the TST solution with PEGDA, and the solution was exposed to UV for 5 min.…”

“…Previous studies have shown that GSGa treatment of cardiac cMSC improves their viability, proliferation, and migration rate without affecting their plasticity [ 49 ]. Our group also demonstrated that GSGa treatment for three days protects cMSC from induced oxidative stress (by H 2 O 2 and CoCl 2 administration), promoting the expression of Antioxidant Responsive Element (ARE) controlled enzymes ( Figure 3 A), such as NAD(P)H dehydrogenase (quinone 1 reductase) (NQO1), and pro-survival and proliferation, inducing proteins such as Bcl-2 and pERK1/2 [ 49 ]. Therefore, we sought to take advantage of these protective effects by preconditioning cMSC with a GSGa treatment prior to their encapsulation in photo-polymerizating hydrogels.…”

“…Given the observed cytoprotective effects of GSGa treatment [ 49 ], we evaluated short-term (three days) preconditioning in the context of PhP damage induced during the gelation process. A solution containing cMSC in PFHy precursors with a photo-initiator was exposed to UVA light for 5 min.…”

“…Importantly, engrafted MSC preconditioned with H 2 S were able to enhance cardiac repair following myocardial infarction in rats [ 47 ]. Moreover, preconditioning of cardiac MSC (cMSC) and bone marrow MSC (BM-MSC) with exogenous H 2 S resulted in an improvement of their therapeutic potential by promoting proliferation and suppressing apoptosis under hypoxia-ischemic conditions [ 48 , 49 ]. Accordingly, H 2 S preconditioning of SCs may ameliorate the survival and efficacy of scaffold-embedded SCs for tissue repair and regeneration.…”

“…Accordingly, H 2 S preconditioning of SCs may ameliorate the survival and efficacy of scaffold-embedded SCs for tissue repair and regeneration. In this context, two cell types—normal human dermal fibroblast (NHDF) and Sca-1 + Lin - human cMSC—were preconditioned with H 2 S-releasing garlic extract (GSGa) [ 30 , 49 ], suspended in a hydrogel precursor solution, and exposed to photo-polymerization damage (PhP damage) of the cross-linking reaction. A PEG-fibrinogen hydrogel (PFHy) [ 11 , 20 , 50 ] was used here as encapsulating photo-polymerizable biomaterial.…”