Oral colon-targeted delivery of recombinant human MANF for alleviation of ulcerative colitis.

Midbrain astrocyte-derived neurotrophic factor (MANF) is a secreted protein induced by endoplasmic reticulum stress. Previous studies have indicated that intravenous administration of 1 mg/kg/day recombinant human MANF protein with His tag (His-MANF) for 3 days can ameliorate acute ulcerative colitis in mice. However, long-term intravenous therapy has many disadvantages. In this paper, His-MANF protein was successfully encapsulated into alginate and hyaluronic acid hybrid hydrogel microcapsules in one step using the gas shear method and then coated by Eudragit S100 to construct an oral colon-targeted delivery system (MSH@E). The MSH@E microcapsules exhibited controlled and sustained release behavior and colon-targeting properties. Both fluorescent imaging and immunohistochemistry staining results showed that His-MANF protein could accumulate in the colitis colon for a longer residence time after oral delivery. In vivo studies demonstrated that oral administration of MSH@E microcapsules could alleviate DSS-induced colitis in mice without systemic toxicity. Importantly, even if the oral His-MANF dose was half of the intravenous His-MANF dose, oral delivery was still much more effective than intravenous injection, suggesting the development of the oral colon-targeted delivery system (MSH@E) has great significance and makes a breakthrough from intravenous to oral administration for His-MANF treatment of ulcerative colitis (UC).