Pseudospin-Induced Asymmetric Field in Non-Hermitian Photonic Crystals with Multiple Topological Transitions

We report the discovery of multiple topological phase transitions induced by the photonic quantum spin Hall effect (PQSHE) in a non-Hermitian photonic crystal (PhC). When increasing the magnitude of the non-Hermitian terms, the system undergoes transitions from topological corner states to topological edge states and subsequently to topological bulk states. The angular momentum of the wave function of the out-of-plane electric field excited by the chiral source acts as the pseudospin degree of freedom in the PQSHE. Therefore, we consider the introduction of chiral sources with different circular polarizations into non-Hermitian PhCs and observe the emergence of asymmetric field responses. These results are expected to enable the multi-dimensional manipulation of topological states, offering a new avenue for the detection of chiral sources

The Regulatory Role of MeAIB in Protein Metabolism and the mTOR Signaling Pathway in Porcine Enterocytes.

Amino acid transporters play an important role in cell growth and metabolism. MeAIB, a transporter-selective substrate, often represses the adaptive regulation of sodium-coupled neutral amino acid transporter 2 (SNAT2), which may act as a receptor and regulate cellular amino acid contents, therefore modulating cellular downstream signaling. The aim of this study was to investigate the effects of MeAIB to SNAT2 on cell proliferation, protein turnover, and the mammalian target of rapamycin (mTOR) signaling pathway in porcine enterocytes. Intestinal porcine epithelial cells (IPEC)-J2 cells were cultured in a high-glucose Dulbecco's modified Eagle's (DMEM-H) medium with 0 or 5 mmoL/L System A amino acid analogue (MeAIB) for 48 h. Cells were collected for analysis of proliferation, cell cycle, protein synthesis and degradation, intracellular free amino acids, and the expression of key genes involved in the mTOR signaling pathway. The results showed that SNAT2 inhibition by MeAIB depleted intracellular concentrations of not only SNAT2 amino acid substrates but also of indispensable amino acids (methionine and leucine), and suppressed cell proliferation and impaired protein synthesis. MeAIB inhibited mTOR phosphorylation, which might be involved in three translation regulators, EIF4EBP1, IGFBP3, and DDIT4 from PCR array analysis of the 84 genes related to the mTOR signaling pathway. These results suggest that SNAT2 inhibition treated with MeAIB plays an important role in regulating protein synthesis and mTOR signaling, and provide some information to further clarify its roles in the absorption of amino acids and signal transduction in the porcine small intestine

Bauerenol inhibits proliferation, migration and invasion of retinoblastoma cells via induction of apoptosis, autophagy and cell cycle arrest

Purpose: To determine the anticancer effects of bauerenol on human retinoblastoma cells. Methods: The effect of bauerenol on cell proliferation was evaluated using 3-(4,5-dimethylthiazol-2-yl)- 2,5-diphenyltetrazolium bromide (MTT) assay, while cancer cell migration and invasion were determined by Transwell assay. Apoptosis of retinoblastoma cells was assessed by Annexin VFITC/PI staining procedure. Autophagy was evaluated using TEM, while cell cycle was studied by flow cytometry. Results: Bauerenol significantly inhibited the proliferation of retinoblastoma cells, with a half-maximal inhibitory concentration (IC50) of 10 μM (p < 0.05). However, bauerenol exhibited a comparatively lower antiproliferative effect on normal paediatric retina cells, with a higher IC50 of 100 μM. Annexin V/PI staining results revealed that the antiproliferative effect of bauerenol was due to apoptotic cell death. The proportion of apoptotic SORB-50 cells increased from about 4 % in control to about 19 % on exposure to 20 μM bauerenol. Western blot assay showed marked up-regulation of LC3B II protein, indicating autophagy. Cell cycle analysis showed that the arrest of SO-RB50 cells at the G2/M phase of the cell cycle markedly contributed to the antiproliferative effects of bauerenol. Moreover, the migration and invasion of SO-RB50 cells were suppressed by bauerenol (p < 0.05). Conclusion: These results indicate that bauerenol suppresses the growth of retinoblastoma cells. Therefore, it may be a beneficial lead molecule for the development of a suitable agent for the treatment of retinoblastoma. Keywords: Retinoblastoma; triterpenoid; anticancer; apoptosis; autophagy; migration; invasion; metastasi