C5L2 modulates BDNF production in human dental pulp stem cells via p38α pathway under LPS-induced inflammation

Abstract: Tissue injury affects nerve fibers and triggers an immune response, leading to inflammation. The complement system gets activated during inflammatory conditions and has been reported to be involved in the regeneration process. We have demonstrated that the C5a receptor (C5aR) has crucial roles in regeneration and healing processes including nerve sprouting and hard tissue formation. Another C5a-like 2 receptor (C5L2) has been cloned which is still considered controversial due to limited studies. We previously established that C5L2 regulates BDNF secretion in pulp fibroblasts. However, there is no study available on human dental pulp stem cells (DPSCs), especially in the inflammatory context. Stem cell therapy is an incipient technique to treat and prevent several diseases, while DPSCs are an emerging option to be considered due to their great ability to differentiate into a variety of cells and secrete nerve regeneration factors. Here, we demonstrated that C5L2 modulates brain-derived neurotropic factor (BDNF) secretion in DPSCs. Our results stated that C5L2 silencing through siRNA can increase the BDNF production which could accelerate the nerve regeneration process. Moreover, stimulation with lipopolysaccharide (LPS) enhanced BDNF production in C5L2 silenced DPSCs. Finally, we quantified BDNF secretion in supernatant and cell lysates using ELISA. Our results showed enhanced BDNF production in C5L2 silenced DPSCs and hampered by the p38^MAPKα inhibitor. Taken together, our data reveal that C5L2 modulates BDNF production in DPSCs via the p38^MAPKα pathway.