Pharmacological validation of a novel exopolysaccharide from Streptomyces sp. 139 to effectively inhibit cytokine storms

Abstract

With the rapid development of immunotherapy in recent years, cytokine storm has been recognized as a common adverse effect of immunotherapy. The emergence of COVID-19 has renewed global attention to it. The cytokine storm's inflammatory response results in infiltration of large amounts of monocytes/macrophages in the lungs, heart, spleen, lymph nodes, and kidneys. This infiltration leads to secondary tissue damage, acute respiratory distress syndrome (ARDS), organismal damage, and even death. However, there is currently no designated treatment for cytokine storm and the resulting ARDS. Consequently, there is a pressing need to identify a pharmaceutical agent that can effectively mitigate cytokine storms. Ebosin is a new exopolysaccharide generated by Streptomyces sp.139 and pharmacological activity for cytokine storm is investigated in vivo. The results show that Ebosin significantly augments the survival rates of mice, and its effectiveness increases with higher doses. It significantly inhibited the expression of cytokines IL-5, IL-6, IL-9 and chemokine Eotaxin in serum and lung tissues. Ebosin can alleviate the pathological damage in the lungs, liver, and spleen caused by LPS. Additionally, it can inhibit the phosphorylation of IKKα/β, Stat3 and NF-κB p65 upon LPS stimulation in vitro. We hypothesized that Ebosin may decrease cytokine release by inhibiting the phosphorylation of IKKα/β, Stat3, and NF-κB p65, neutrophil infiltration in animals. The article preliminarily elucidated the activity and mechanism of Ebosin against cytokine storm, which provides a reference for the study of anti-cytokine storm activity of microbial natural products.

Keywords

• Cytokine storm
• Ebosin
• LPS
• COVID-19