Bioinformatics-Guided Mechanistic Insights into Scutellaria Barbata Flavonoids Improving CREB Signaling-Related
Yan Chen1, Chaojie Zhang1, Xiaomin Yu1
1Institute of Traditional Chinese Medicine, Chengde Medical University, Chengde, 067000, China.
Introduction:
There is evidence showing that cognitive dysfunction is a typical characteristic in Alzheimer's Disease (AD) patients. CREB signaling-related neuronal dysfunction through ERK-RSK-CREB is a subtype of the pathological mechanism of AD. The present study aimed to investigate whether Scutellaria Barbata Flavonoids (SBFs) ameliorate the rats' cognitive impairment by targeting the ERK-RSK-CREB signaling pathway, utilizing the CREB indirect inhibition model by a specific ribosomal S6 kinase (RSK) inhibitor BI-D1870 application.
Methods:
Bioinformatics analysis was conducted to identify key pathways involved in AD. Based on this, an in vivo memory impairment model of related-AD was established in rats by indirect inhibition of CREB via intraperitoneal injection of the RSK inhibitor BI-D1870. Following successful memory impairment model of related-AD rats screening with the Morris water maze, the successful model rats were treated with SBFs (140 mg/kg) or the CREB activator Rolipram (0.5 mg/kg). Spatial and short-term memory were assessed using the Barnes maze and the Passive Avoidance Test, respectively. NeurN and Nissl body for neuronal integrity and the expression of ERK-RSK-CREB pathway-related molecules (p-CREB-Ser133/Ser142, RSK, CREB, EGR-1) were evaluated by histological staining, immunohistochemistry, and molecular biology techniques.
Results:
Bioinformatics analysis identified the MAPK signaling pathway as a key pathway for further investigation. Experimentally, SBFs administration significantly improved both spatial and short-term memory deficits induced by BI-D1870. This cognitive recovery was associated with the restoration of neuronal Nissl bodies and NeuN expression. Mechanistically, SBFs upregulated the phosphorylation of CREB at Ser133 and the expression of RSK, CREB, and EGR-1 mRNA and/or protein, while concurrently downregulating the elevated phosphorylation of CREB at Ser142, which demonstrated the bidirectional regulatory mechanism of SBFs on CREB phosphorylation of the ERK-RSK-CREB pathway.
Discussion:
This study demonstrates that BI-D1870 can cause the rats' memory deficits, and SBFs can mitigate BI-D1870-induced memory deficits by enhancing ERK-RSK-CREB signaling, similar to Rolipram. SBFs restored neuronal integrity (Nissl bodies, NeuN) and upregulated p- CREB-Ser133, RSK, CREB, and EGR-1, suggesting SBFs' neuroprotection. These findings highlight SBFs as a potential therapeutic agent for memory disorders via CREB pathway modulation. However, our research has some limitations. Bioinformatics identified the key signaling pathway involved in AD, but the BI-D1870 model merely estimates AD-related cognitive dysfunction; it does not recapitulate the full spectrum of AD pathology. Future studies should validate the efficacy, mechanisms, bioactive substances, and metabolized root of SBFs in more etiologically relevant transgenic AD models.
Conclusion:
Our findings indicate that SBFs exert neuroprotective effects against CREB indirect inhibitor-induced cognitive dysfunction, likely through the modulation of the ERK-RSK-CREB pathway. This suggests SBFs as a potential candidate for mitigating memory deficits associated with CREB dysregulation.