Nobiletin enhances mitochondrial function by regulating SIRT1/PGC-1α signaling in porcine oocytes during in vitro maturation.

Nobiletin is a natural flavonoid found in citrus fruits with beneficial effects, including anti-inflammatory, anti-cancer and anti-oxidation effects. The aim of this study was to investigate whether nobiletin improves mitochondrial function in porcine oocytes and examine the underlying mechanism. Oocytes enclosed by cumulus cells were cultured in TCM-199 for 44 h with 0.1% dimethyl sulfoxide (control), or supplemented with 5, 10, 25, and 50 µM of nobiletin (Nob5, Nob10, Nob25, and Nob50, respectively). Oocyte maturation rate was significantly enhanced in Nob10 (70.26 ± 0.45%) compared to the other groups (control: 60.12 ± 0.47%; Nob5: 59.44 ± 1.63%; Nob25: 63.15 ± 1.38%; Nob50: 46.57 ± 1.19%). The addition of nobiletin reduced the levels of reactive oxygen species and increased glutathione levels. Moreover, Nob10 promoted mitochondrial biogenesis by upregulating the protein levels of sirtuin 1 (SIRT1) and peroxisome proliferator-activated receptor-gamma coactivator 1α (PGC-1α). This resulted in an increase in the number of active mitochondria, mitochondrial DNA copy number, mitochondrial membrane potential, and ATP production, thereby enhancing mitochondrial function. The protein level of p53 decreased, followed by the phosphorylation of B-cell lymphoma 2, suggesting a reduction in mitochondria-mediated apoptosis in the Nob10 group. Additionally, the release of cytochrome c from the mitochondria was significantly diminished along with a decrease in the protein expression of caspase 3. Thus, nobiletin has a great potential to promote the in vitro maturation of porcine oocytes by suppressing oxidative stress and promoting mitochondrial function through the upregulation of the SIRT1/PGC-1α signaling pathway.

Poly(caffeic acid)-coated molecularly imprinted magnetic nanoparticles for specific and ultrasensitive detection of glycoprotein.

Molecularly imprinted polymers (MIPs) are artificial chemical receptors, and can recognize template molecules with a high selectivity and affinity. As "antibody mimics", MIPs have been widely studied in various fields. However, the general applicability of MIPs is limited by the type of functional monomers. Herein, we developed caffeic acid (CA, a natural polyphenol) as novel a functional monomer. An innovative poly(caffeic acid)-coated molecularly imprinted magnetic nanoparticles (PCA-MIMN) with transferrin (TRF) as a model glycoprotein template was fabricated by autoxidation of CA with hexamethylenediamine (HMDA) in an aerobic environment as imprinted layer. The successful fabrication of PCA-MIMN was proved in detail by diversified characterization. The PCA-MIMN exhibited not only outstanding binding affinity and specificity for target glycoprotein, but also excellent hydrophilicity due to the externally generous hydrophilic groups. To evaluate the preeminent performance, the PCA-MIMN was linked with pH-triggered allochroic-graphene oxide (AGO), which was used for determination of TRF in real samples. The proposed PCA-MIMN linked AGO strategy exhibited ultrahigh sensitivity with limit of detection of 0.38 pg mL-1 for TRF. Finally, the proposed strategy was successfully applied in determination of TRF in spiked human serum sample with recovery and relative standard deviation in the range of 97.2%-103.9% and 4.6%-5.8%, respectively. This work demonstrates that the "autoxidation of CA with HMDA" may be a universal tool for synthesis of highly specific MIPs, and the type of functional monomers will increase exponentially due to the presence of numerous polyphenols in nature.