Mechanistic Advances in the Therapeutic Application of Bixin for Lung Inflammation In Vitro and In Vivo
Alexsandro Tavares Figueiredo-Junior1,2, Bruno Clemente Brandão Marques1, Douglas Galdino Dos Santos1
1Programa de Pós-Graduação em Farmacologia e Química Medicinal, Instituto de Ciências Biomédicas, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Cidade Universitária, Rio de Janeiro 21941-902, RJ, Brazil.
Abstract:
Background: Nrf2 plays a key role in regulating the antioxidant response against oxidative stress. Therefore, it is imperative to examine the advantages of Nrf2 activation by new small molecules capable of inhibiting the Nrf2-Keap1 protein interaction that do not present electrophilic sites, since electrophilic compounds have intrinsic toxicity. The bixin pigment has been used as a form of treatment and prevention of several pathological conditions in animal models since it was described as an Nrf2 activator without electrophilic sites. This study aims to synthetize a soluble derivate KBx (potassium bixinate) and evaluate its ability to activate Nrf2/ARE in a model of exposure to cigarette smoke extract (CSE; in vitro) and intranasal LPS administration (in vivo). Methods: In the in vivo study, C57BL/6 mice were pretreated with 200 mg/kg of KBx (gavage) during 5 consecutive days and then challenged with 60 µg of LPS i.n. for 16 h. Bronchoalveolar lavage was collected to examine cytokines dosage. In the in vitro study, RAW 264.7 macrophages were exposed to CSE and post-treated with KBx to evaluate their ability to revert the redox imbalance caused by the stressor. Results: KBx was characterized using mass spectrometry (433.1778 m/z). KC levels were increased in the LPS group (p = 0.021), and KBx inhibited this (p = 0.001). IL-10 levels were decreased (p = 0.055) in the LPS group that was prevented when pretreated with KBx (p = 0.037). The in vitro study showed KBx to be a more potent derivate of bixin through its ability to intercept ROS formation with three-fold more potency, and it showed an anti-inflammatory propriety by reducing the nuclear translocation of p65 (p < 0.001). Conclusions: In conclusion, these data suggest that KBx was able to activate the Nrf2/ARE pathway and intercept ROS formation induced by CSE and LPS in both in vivo and in vitro studies.
Insights
Potassium bixinate (KBx), a novel Nrf2 activator, effectively combats oxidative stress and inflammation. This study demonstrates KBx’s potential in mitigating damage from cigarette smoke extract and LPS exposure in both cellular and animal models.
Area of Science:
- Biochemistry
- Pharmacology
- Toxicology
Background:
- Nuclear factor erythroid 2-related factor 2 (Nrf2) is crucial for antioxidant response.
- Electrophilic compounds activating Nrf2 have toxicity; non-electrophilic activators are sought.
- Bixin, a non-electrophilic Nrf2 activator, shows therapeutic potential.
Purpose of the Study:
- Synthesize a soluble bixin derivative, potassium bixinate (KBx).
- Evaluate KBx's efficacy in activating the Nrf2/ARE pathway.
- Assess KBx's protective effects against oxidative stress and inflammation in vitro and in vivo models.
Main Methods:
- In vivo: C57BL/6 mice pretreated with KBx then challenged with LPS.
- In vitro: RAW 264.7 macrophages exposed to cigarette smoke extract (CSE) and treated with KBx.
- Analysis included cytokine dosage, reactive oxygen species (ROS) interception, and p65 translocation.
Main Results:
- KBx treatment reduced LPS-induced KC and prevented IL-10 decrease in vivo.
- In vitro, KBx showed threefold higher potency in ROS interception compared to bixin.
- KBx significantly reduced p65 nuclear translocation, indicating anti-inflammatory effects.
Conclusions:
- KBx effectively activates the Nrf2/ARE pathway.
- KBx demonstrates potent ROS scavenging and anti-inflammatory properties.
- KBx shows promise as a therapeutic agent against CSE and LPS-induced damage.
