R15 - Paquinimod-loaded hyaluronic acid-green tea catechin microgels with inherent antioxidative and immunoregulation abilities ameliorates bleomycin-induced acute lung injury

Introduction: : Acute lung injury (ALI) and acute respiratory syndrome (ARDS) are common life-threatening lung diseases associated with acute and hyper inflammation, and caused by various factors. Approximately 200,000 individuals are diagnosed with ALI/ARDS in the United States each year, and the mortality remains 30-40% in most cases despite advances in modern supportive care and decades of research on clinical ALI/ARDS. Cytokine storm is one of the major mechanisms contributing to ALI/ARDS and its progression, involving an excessive stress response generated by immune cells to exotically harmful substances and pathogenic microorganisms. As most cases progress from ALI to ARDS within a few days of hospitalization, developing molecular-based therapies to interrupt this progression is an attractive endeavor due to their potential for early intervention and improved patient outcomes. Therefore, the development of a targeted therapeutic delivery platform, along with effective and safe treatment strategies, remains critical for the early intervention of excessive and uncontrolled systemic inflammatory responses in ALI/ARDS therapy. The objective of this study is to develop a novel multifunctional microgel loading specific drug (such as S100A9i, Paquinimod), aiming to effectively treat lung injury in a mouse bleomycin-induced ALI model.

Materials and

Methods: : We first synthesized a phenylboronic acid (PBA)- EGCG complex and then generated an HA-PBA-EGCG (HPE) microgels by the copolymerization of HA and the PBA-EGCG complex (Figure 1A). The cytocompatibility of the HPE microgels was assessed via a MTT assay after culturing human lung fibroblasts (HLF). The blood compatibility of HPE microgels was evaluated by measuring the human red blood cell (RBC) lysis during their co-incubation with the microgels. Subsequently, we explored the multiple functionalities of microgels, including anti-oxidation, and anti-inflammation in vitro. Furthermore, we developed a mouse bleomycin-induced acute lung injury model and verified the retention time of HPE microgel in vivo (Figure 1F, G).

Results, Conclusions, and Discussions:: As shown in Figure 1B, he HPE microgel had no significant cytotoxicity on HLF and RBCs and exhibited promising antioxidative and anti-inflammatory properties by reducing intracellular reactive oxygen species (ROS, Figure 1C), and downregulating pro-inflammatory gene expression (Il6) and cytokine secretion (IL-6) (Figure 1E). In addition, we developed a mouse bleomycin-induced ALI model (Figure 1F). Compared to the normal mouse (PBS)in H&E images (Figure 1G), serious lung injury was observed for the Bleomycin-induced ALI mouse model as the result of large amounts of infiltrated inflammatory cells and proliferation of epithelioid cells. Meanwhile, IVIS images indicated the retention time of Cy7.5-labeled HPE microgel is over 14 days in vivo (Figure 1H).

Acknowledgements and/or References (Optional):: Scientist Development Award (Department of Internal Medicine, University of Nebraska Medical Center); University of Nebraska Collaboration Initiative Grant; Great Plains IDeA-CTR Network.