Targeting notch1 with berbamine alleviates the inflammatory responses of macrophages in sepsis.

Background: Sepsis is a life-threatening condition characterized by an excessive inflammatory response and immune dysregulation. Effective treatments remain limited, necessitating the exploration of novel therapeutic agents. Although berbamine (BBM) exhibits notable anti-inflammatory properties, its specific mechanisms and therapeutic potential in sepsis have yet to be elucidated.

Purpose: This study aims to investigate the protective effects of BBM in sepsis models and elucidate its underlying mechanisms, with a focus on immune modulation and the Notch1 signaling pathway.

Methods: We employed two murine sepsis models-lipopolysaccharide (LPS)-induced endotoxemia and cecal ligation and puncture (CLP)-induced sepsis-to assess BBM's therapeutic potential. Histopathological and cytokine analyses were performed to evaluate inflammation and lung injury. Flow cytometry was used to examine immune cell development. Additionally, in vitro assays with bone marrow-derived macrophages (BMDMs) were conducted to assess cytokine production. Network pharmacology and cellular thermal shift assays (CETSA) were utilized to identify potential molecular targets, focusing on Notch1 signaling. We also evaluated the effects of BBM on myeloid-specific Notch1 knockout (Notch1) mice.

Results: BBM significantly improved survival rates and reduced lung inflammation in septic mice. In vitro, BBM inhibited LPS-induced secretion of proinflammatory cytokines (TNF-α, IL-6, and IL-1β) in BMDMs without impairing macrophage differentiation or viability. Network pharmacology analyses identified Notch1 as a potential BBM target, which was validated by CETSA. Mechanistically, BBM accelerated Notch1 degradation via the ubiquitin-proteasome pathway, leading to decreased Notch1 protein levels. Notably, notch1-deficient macrophages exhibited blunted inflammatory responses to LPS, and BBM treatment failed to confer additional suppression, indicating that BBM's anti-septic effects are mediated predominantly through Notch1 inhibition.

Conclusion: BBM exerts a protective effect in sepsis by suppressing inflammation and promoting Notch1 degradation. These findings suggest that BBM may serve as a promising therapeutic agent for sepsis.