Cytoprotective and Neuroinductive Effects of Thiol-Containing Simple Signaling Molecules

Purpose Around 20 million Americans, mostly young adults, have suffered from a peripheral nerve injury due to trauma or a medical condition. However, prevailing treatments, including those that employ exogenous growth factors, often exhibit drawbacks outweighing their benefits, highlighting the need for novel solutions. Non-complex agents that govern bioactivity, termed simple signaling molecules (SSMs), offer an exciting alternative when compared to traditional approaches due to their small size, ready availability, and influence on cellular pathways. This study explores the cytoprotective and neuroinductive effects of three thiol-containing SSMs: hydrogen sulfide (H2S), N-acetyl cysteine (NAC), and glutathione (GSH). Methods Neural stem cells (NE-4Cs) were exposed to toxic levels of hydrogen peroxide (H2O2) while supplemented with different concentrations of H2S, NAC, or GSH to assess their cytoprotective effects. To study the neuroinductivity of H2S, NAC, and GSH with NE-4Cs, immunofluorescence microscopy for an early neuronal marker, beta 3-tubulin, was employed to determine stem cell neural differentiation. Results Significant cytoprotection was found for NAC (2-8 mM) and GSH (2-12 mM), while H2S showed limited protective effects. Interestingly, the opposite result was observed for neuroinductivity as only H2S (7.75-125 mu M) achieved a desirable effect while NAC and GSH had minimal impact on neural differentiation. Conclusion This research establishes functional concentration ranges of H2S, NAC, and GSH for future drug delivery systems targeting neural regeneration, especially for peripheral nerve injuries.