Induction of systemic immunity through nasal-associated lymphoid tissue (NALT) of mice intranasally immunized with Brucella abortus malate dehydrogenase-loaded chitosan nanoparticles

Infection with Brucella abortus causes contagious zoonosis, brucellosis, and leads to abortion in animals and chronic illness in humans. Chitosan nanoparticles (CNs), biocompatible and nontoxic polymers, acts as a mucosal adjuvant. In our previous study, B. abortus malate dehydrogenase (Mdh) was loaded in CNs, and it induced high production of pro-inflammatory cytokines in THP-1 cells and systemic IgA in BALB/C mice. In this study, the time-series gene expression analysis of nasal-associated lymphoid tissue (NALT) was performed to identify the mechanism by which Mdh affect the target site of nasal immunization. We showed that intranasal immunization of CNs-Mdh reduced cell viability of epithelial cells and muscle cells at first 1 h, then induced cellular movement of immune cells such as granulocytes, neutrophils and lymphocytes at 6h, and activated IL-6 signaling pathway at 12h within NALT. These activation of immune cells also promoted signaling pathway for high-mobility group box 1 protein (HMGB1), followed by the maturation of DCs required for mucosal immunity. The CNs also triggered the response to other organism and inflammatory response, showing it is immune-enhancing adjuvant. The ELISA showed that significant production of specific IgA was detected in the fecal excretions and genital secretions from the CNs-Mdh-immunized group after 2 weeks-post immunization. Collectively, these results suggest that B. abortus Mdh-loaded CNs triggers activation of HMGB1, IL-6 and DCs maturation signaling within NALT and induce production of systemic IgG and IgA.

Molecular-Level Interactions between Engineered Materials and Cells

Various recent experimental observations indicate that growing cells on engineered materials can alter their physiology, function, and fate. This finding suggests that better molecular-level understanding of the interactions between cells and materials may guide the design and construction of sophisticated artificial substrates, potentially enabling control of cells for use in various biomedical applications. In this review, we introduce recent research results that shed light on molecular events and mechanisms involved in the interactions between cells and materials. We discuss the development of materials with distinct physical, chemical, and biological features, cellular sensing of the engineered materials, transfer of the sensing information to the cell nucleus, subsequent changes in physical and chemical states of genomic DNA, and finally the resulting cellular behavior changes. Ongoing efforts to advance materials engineering and the cell-material interface will eventually expand the cell-based applications in therapies and tissue regenerations.