A fusion protein of IL4 and IL10 (IL4-10 synerkine), is very effective in protecting cartilage from blood-induced damage

Abstract

Purpose: Interleukin 4 (IL4), IL10 or the combination of both protects cartilage from blood-induced damage in vitro. Because IL4 and IL10 use different signaling pathways they are able to exert different, but also potentially additive effects. It has been postulated that they can act in synergy enhancing their beneficial effects and controlling their individual adverse effects. Therefore a combination of IL4 and IL10 might be the best option to administer in vivo. To overcome the low bioavailability of IL4 and IL10 in vivo, a fusion protein has been developed: IL4-10 synerkine. It has been demonstrated that this novel drug inhibits numerous pro-inflammatory cytokines secreted by monocytes and T-cells. This study investigates whether this IL4-10 synerkine protects against blood-induced cartilage damage similarly as the combination of the individual components. Methods: Human cartilage explants were exposed to 50% v/v whole blood for 4 days and simultaneously to a broad concentration range (0-100 ng/mL) of the IL4-10 synerkine. Effects of 10 ng/mL IL4-10 synerkine were compared to the same concentrations of the individual cytokines and the combination. Cartilage matrix proteoglycan turnover was assessed after a recovery period of 12 days. Moreover, the influence of IL4-10 synerkine (10 ng/mL) and its individual components on levels of IL1β and IL6 were investigated in a 4 days 50% v/v whole blood culture. Results: Exposure to 50% v/v whole blood resulted in a clear statistical significant decrease of proteoglycan (PG) synthesis rate (-74%; p = 0.012) and an increase of PG release (+92%, p = 0.017) compared to control. Adding of IL4-10 synerkine, resulted in a clear dose-response curve, leading to full normalisation of PG synthesis rate and -release at higher concentrations (>10 ng/mL). These results were similar to the effect of the two individual cytokines combined (see figure). The individual cytokines had a more distinct profile where IL4 was superior over IL10 (see figure). Moreover, addition of IL4-10 synerkine reduced IL1β and IL6 production in whole blood cultures to control levels (both p < 0.05), similar to the combination of IL4 plus IL10 (p = 0.180 and p = 0.173, respectively). Conclusions: IL4-10 synerkine strongly protects against blood-induced cartilage damage in vitro, presumably at least in part by reduction of pro-inflammatory cytokines including IL1β and IL6. Considering better bioavailability and more easy application of this synerkine compared to the individual cytokines, testing the IL4-10 synerkine in an in vivo model of blood-induced cartilage damage is warranted.