Early immune response in large yellow croaker (Larimichthys crocea) after immunization with oral vaccine.

Mesoporous silica nanoparticles (MSNs) have been used in the field of biomedicine as antigen carriers and adjuvants for protective antigens. In the present study, an oral nanovaccine against Vibrio alginolyticus was prepared employing MSNs as carriers. The uptake of the dihydrolipoamide dehydrogenase (DLDH) antigens in the intestine of large yellow croaker was evaluated using an immunohistochemistry assay. Additionally, the effects of the nanovaccine on the early immune response in large yellow croaker were investigated via oral vaccination. The presence of the antigens was detected in the mucosa and lamina propria of the foregut, midgut, and hindgut of large yellow croaker at 3 h following oral immunization. The expression levels of cytokines (i.e., lysozyme, IFN-γ, IFITM, TNF-α, IL-1ß, IL-2, IL-4, IL-10, and IL-13) in the intestine, spleen, and head kidney tissues of large yellow croaker before and after the immune challenge were determined via RT-qPCR assay. The obtained results revealed that the expression levels of lysozyme, IFN-γ, IFITM, TNF-α, IL-1ß, IL-2, IL-4, IL-10, and IL-13 in the intestine and head kidney of the vaccinated large yellow croaker, as well as the expression of lysozyme, IL-1ß, and IL-10 in the spleen, exhibited time-dependent oscillation regulation patterns. Notably, the nanovaccine immunization could induce early (6 h) and high expression of IFN-γ in the spleen and kidney tissues after the bacterial infection. The current study supplements the available data on the early immune response to fish nanovaccines. It also provides a valuable theoretical basis for the future development of large yellow croaker oral vaccines.

Targeting the Achilles' heel of cancer cells via integrin-mediated delivery of ROS-generating dihydrolipoamide dehydrogenase.

Cancer cells frequently exhibit higher levels of reactive oxygen species (ROS) than normal cells and when ROS levels increase beyond a cellular tolerability threshold, cancer cell death is enhanced. The mitochondrial dihydrolipoamide dehydrogenase (DLDH) is an enzyme which produces ROS in association with its oxidoreductive activity and may be thus utilized as an exogenous anticancer agent. As cancer cells often overexpress integrins that recognize RGD-containing proteins, we have bioengineered the human DLDH with RGD motifs (DLDHRGD) for integrin-mediated drug delivery. The modified protein fully retained its enzyme activity and ROS-production capability. DLDHRGD uptake by cells was shown to depend on the presence of cell-associated integrin αvß3, as comparatively demonstrated with normal kidney cells (HEK293) transfected with either ß1 (αvß1 positive) or ß3 integrins (αvß3 positive). The interaction with ß3 integrins was shown to be competitively inhibited by an RGD peptide. In mice melanoma cells (B16F10), which highly express an endogenous αvß3 integrin, fast cellular uptake of DLDHRGD which resulted in cell number reduction, apoptosis induction, and a parallel intracellular ROS production was shown. Similar results were obtained with additional human melanoma cell models (A375, WM3314, and WM3682). In contrast, HEK293ß3 cells remained intact following DLDHRGD uptake. The high pharmacological safety profile of DLDHRGD has been observed by several modes of administrations in BALB/C or C57Bl/6 mouse strains. Treatments with DLDHRGD in a subcutaneous melanoma mice model resulted in significant tumor inhibition. Our study demonstrated, in vitro and in vivo, the development of a unique platform, which targets cancer cells via integrin-mediated drug delivery of an exogenous ROS-generating drug.