Targeting Both Hyperinflammation and Pyroptosis Via Nanotherapeutics to Improve Outcomes in Gram-Negative Sepsis

PROJECT SUMMARY Sepsis is a complex, heterogenous disease that results in a dysregulated immune response. It is associated with hyperinflammation, known as “cytokine storm”, causing multiple organ failure and death, as well as simultaneous compensatory anti-inflammatory responses, leading to immune suppression by abundant anti- inflammatory cytokine secretion and immune cell death. Sepsis survivors may suffer chronic critical illness, known as Persistent Inflammation, Immunosuppression, and Catabolism Syndrome (PIICS), leading to serious complications and later death. In sepsis triggered by Gram negative bacterial infection, lipopolysaccharide (LPS), an endotoxin, promotes uncontrolled inflammation and cytokine storm through TLR4 activation. It can also trigger significant cell-lytic death of immune cells, known as inflammasome-mediated pyroptosis, which promotes further immune response for pathogen clearance. However, excessive pyroptosis during hyperinflammation results in prolonged immunosuppression and increased organ dysfunction, contributing to the development of PIICS. Currently, there are no available therapies to directly target both excessive cytokine production and immune cell pyroptosis in sepsis, a gap we will fill with our novel immune modulating itaconate- loaded telodendrimer nanoparticles (ITA:TD NP). In Luo lab, we have developed a series of bioactive immune modulating TD nanodrugs, which mimic the molecular pattern of LPS (multivalent charge and fatty acid tails). As a result, the optimized TD nanodrug attenuates LPS-induced inflammation via competitive binding with TLR4. Itaconate, a metabolite produced by activated macrophages, is known inhibit immune cell pyroptosis. Unfortunately, the in vivo application of ITA is limited by the unfavorable pharmacokinetic properties and cytotoxicity. Our LPS-antagonizing TD nanodrug can form a nanocarrier for efficient encapsulation of itaconate, thus to synergize the in vivo application and immune modulation. We hypothesize that concurrent inhibition of LPS signals, inflammasome activation, and membrane pore formation will effectively control both early phase hyperinflammation and pyroptosis-mediated later stage PIICS for improved sepsis treatment. Preliminary results indicate a survival benefit with ITA:TD NP treatment in septic mice induced by LPS and effective inhibition of both inflammation and pyroptosis. Thus, further studies to evaluate ITA:TD NP mechanism of action and efficacy to prevent both acute and late death in sepsis are needed. The aims of this study are: 1) investigate ITA:TD NP-mediated inhibition of hyperinflammation in sepsis, and 2) elucidate the protective effect of ITA:TD NP to prevent PIICS-associated morbidity and mortality. Results from these studies will provide insight to the mechanism of action of ITA:TD NP and its therapeutic potential for concurrent treatment of hyperinflammation and prevention of PIICS in sepsis to reduce mortality and fill this critical gap in patient care.