Transcriptomic evidence of black soybean ethanolic extract and 2-aminobutyric acid in suppressing neuroinflammation and enhancing synaptic transmission.

Introduction: Recently, the awareness of the beneficial utilization of natural bioactive compounds in treating neuroinflammation has gained particular attention. We aimed to understand the anti-neuroinflammatory effect of black soybeans (Glycine max (L.) Merr) ethanolic extract (BBEE) and its bioactive compound, 2-aminobutyric acid (2-AB), against LPS-induced SH-SY5Y cells.

Method: Cell viability and the optimum therapeutic dose were confirmed by MTT assay. We conducted a whole-transcriptomic analysis of BBEE and 2-AB in LPS-induced SH-SY5Y cells using microarray normalized with SST-RMA. DEGs were selected based on p-value < 0.05 and fold change > 2, and validated by RT-qPCR and immunocytochemical analyses.

Results: We found that both BBEE and 2-AB down-regulated the expression of inflammatory cytokines IL6 and TNFA under LPS-induced conditions. This was also observed in the microarray data, showing downregulation of several inflammatory pathways, such as NF-kB, and IL6-JAK/STAT3-signaling pathways. In contrast, it upregulated the expression of CALML3, GRIN2, and GRIA2 gene expressions, which influence the AMPK and CAMK2 signaling pathways, indicating the potential of BBEE in neurotransmission and synaptic function. Also, immunofluorescence analysis revealed that 2-AB treatment significantly increased PSD-95 and Ca levels, suggesting its effect on synaptic transmission essential for brain function.

Conclusion: Our findings suggest the potential anti-neuroinflammatory effects of BBEE and 2-AB, which may offer therapeutic and preventive benefits in mitigating neurological disorders. Given that BB is widely consumed in many Asian countries, our study may encourage its incorporation into the daily diet to slow inflammation-induced neurodegenerative disorders, reduce age-related cognitive decline, and enhance overall brain function.