Enhancement of the anticancer potential and biosafety of BSA-modified, bacterial membrane-coated curcumin nanoparticles.

Bacteria and bacterial components have been widely used as bionanocarriers to deliver drugs to treat tumors. In this study, we isolated bacterial outer membrane vesicles (OMVs) with good stability and high yield for macrophage polarization and cell recruitment. Using ultrasound baths, these bacterial OMVs were combined with curcumin nanoparticles (OMV CUR NPs), following which these nanoparticles were modified with bovine serum albumin (BSA) to achieve high biosafety and tumor-targeting effects. The particle size, PDI, and zeta potential of the BSA-OMV CUR NPs were 157.9 nm, 0.233, and -15.1 mV, respectively. The BSA-OMV CUR NPs exhibited high storage stability, low cytotoxicity, sustained release, enhanced cellular uptake of CUR, induction of tumor cell apoptosis, and inhibition of tumor cell proliferation and migration. By determining the survival rate, body length, heart rate, head size, eye size, and pericardium size of the zebrafish, we found that the BSA-OMV CUR NPs were safe for application in vivo. Moreover, an increase in antiproliferation, antiangiogenic and antimetastatic effects of BSA-OMV CUR NPs was demonstrated in wild-type and transgenic tumor-transplanted zebrafish embryos.

PbbHLH155 enhances iron deficiency tolerance in pear by directly activating PbFRO2 and PbbHLH38.

Iron (Fe) deficiency is a general stress for many horticulture crops, causing leaf chlorosis and stunted growth. The basic-helix-loop-helix (bHLH) transcription factor (TF) was reported to function in Fe absorption; however, the regulatory mechanism of bHLH genes on iron absorption remains largely unclear in pear. In this study, we found that PbbHLH155 was significantly induced by Fe deficiency. Overexpression of PbbHLH155 in Arabidopsis thaliana and pear calli significantly increases resistance to Fe deficiency. The PbbHLH155-overexpressed Arabidopsis lines exhibited greener leaf color, higher Fe content, stronger Fe chelate reductase (FCR) and root acidification activity. The PbbHLH155 knockout pear calli showed lower Fe content and weaker FCR activity. Interestingly, PbbHLH155 inhibited the expressions of PbFRO2 and PbbHLH38, which were positive regulators in Fe-deficiency responses (FDR). Furthermore, yeast one-hybrid (Y1H) and Dual-Luciferase Reporter (DLR) assays revealed that PbbHLH155 directly binds to the promoters of PbFRO2 and PbbHLH38, thus activating their expression. Overall, our results showed that PbbHLH155 directly promote the expression of PbFRO2 and PbbHLH38 to activate FCR activity for iron absorption. This study provided valuable information for pear breeding.