杨芽黄素对前列腺癌细胞凋亡的影响及其机制

目的:探讨杨芽黄素对前列腺癌细胞22Rv.1的作用及机制。方法:将0~20μg/ml杨芽黄素作用于22Rv.1细胞和正常前列腺细胞RWPE-1,适时采用MTS法检测细胞的增殖活性,采用流式细胞仪、hoechst染色、LDH释放实验分别检测22Rv.1细胞凋亡、死亡、周期、核型变化和药物的细胞毒作用,利用qPCR和Westernblot分析22Rv.1细胞内基因转录和蛋白表达的改变,并通过抑瘤实验证实该药的抑癌作用。结果:杨芽黄素可显著抑制22Rv.1细胞增殖、诱导其凋亡,促进22Rv.1细胞凋亡相关基因dr4、dr5、trail、p53、caspase-3、caspase-8、caspase-9、bid、bax、foxo3的表达,并抑制抗凋亡基因akt、pi3k和bcl-2的表达。结论:杨芽黄素可通过影响TRAIL和PI3K/AKT信号通路诱导前列腺癌细胞凋亡,具有抗前列腺癌的作用。     

Proteomic analysis of glutamate-induced toxicity in HT22 cells

In the present study, we have investigated the proteome changes associated with glutamate-induced HT22 cell death, a model system to study oxidative stress-mediated toxicity. Among a number of HT22 proteins exhibiting altered expression, several molecular chaperones demonstrated substantial changes. For example, the levels of Hsp90 and Hsp70 decreased as cell death progressed whereas that of Hsp60 increased dramatically. Interestingly, cytosolic Hsp60 increased more prominently than mitochondrial Hsp60. Concomitantly, the accumulation of poly-ubiquitylated proteins and differential regulation of the peptidase activities and the subunits of 26S proteasomes were observed in glutamate-treated HT22 cells. Our findings that the molecular chaperones and the ubiquitin-proteasome system undergo changes during glutamate-induced HT22 cell death may suggest the importance of a protein quality control system in oxidative damage-mediated toxicity.     

The pathogenesis of thyroid autoimmune diseases: New T lymphocytes – Cytokines circuits beyond the Th1−Th2 paradigm

Autoimmune thyroid disease (AITD) is one of the most common organ-specific autoimmune disorders. It mainly manifests as Hashimoto's thyroiditis (HT) and Graves’ disease (GD). HT is characteristic of hypothyroidism resulting from the destruction of the thyroid while GD is characteristic of hyperthyroidism due to excessive production of thyroid hormone induced by thyrotropin receptor-specific stimulatory autoantibodies. T lymphocytes and their secretory cytokines play indispensable roles in modulating immune responses, but their roles are often complex and full of interactions among distinct components of the immune system. Dysfunction of these T cells or aberrant expressions of these cytokines can cause the breakdown of immune tolerance and result in aberrant immune responses during the development of AITDs. This review summarizes recently identified T subsets and related cytokines and their roles in the pathogenesis of AITDs with the hope to provide a better understanding of the precise roles of notably identified T subsets in AITDs and facilitate the discovery of functional molecules or novel immune therapeutic targets for AITDs.     

Effect of gap junction-mediated intercellular communication on TGF-β induced epithelial-to-mesenchymal transition

Epithelial-to-mesenchymal transition (EMT) is the process in which epithelial cells lose cell polarity and cell adhesion with surrounding cells to obtain migratory and invasive abilities. On the other hand, the expression of connexin is decreased or lacked in the many types of tumor cells. This study examined the effect of gap junctional intercellular communication (GJIC) on EMT induced by the transforming growth factor-β1 (TGF-β1). To investigate the effect of GJIC on EMT in U2OS cells, smooth muscle 22-α (sm22α) promoter-driven luciferase reporter gene was introduced into Cx43-expressing cells (U2OS-Luc Cx43) and into the control parental cell line (U2OS-Luc). TGF-β1 induced the expression of EMT markers and the sm22α promoter activity of U2OS-Luc cells. Sm22α promoter activity of U2OS cells was neither dependent on the expression of Cx43 nor on the establishment of GJIC among U2OS cells. Furthermore, we found that the homocellular communication among tumor cells did not affected the tumor cell growth and migration. However, we revealed that tumor cell density was an important factor for tumor cells to acquire metastatic phenotype. Interestingly, the co-culture of U2OS cells with osteoblasts revealed that sm22α promoter activity was inhibited only by the GJIC established between these two cell types. These results suggest that normal osteoblast cells negatively regulate the EMT of tumor cells, at least in part. Thus, Cx43-mediated GJIC may have anti-metastatic activity in tumor cells. Our findings provide a new insight into the role of GJIC in cancer progression and metastasis and identify potential therapeutic targets for the treatment of cancer.     

Cryoprotectant toxicity in Caenorhabditis elegans

We have looked at the effects of the cryoprotectant M22 upon viability in the model organism C. elegans. M22 is a well-known vitrification solution which has been successfully used in the laboratory to preserve organs destined for transplantation. M22 reduces survival of C. elegans in a concentration-dependent manner. M22 at concentrations of 10% (v/v) or higher inhibits progeny production and development. A few mutants in the ILS (insulin-like signaling) pathway of C. elegans are more resistant to the toxic effect of M22 compared to wild-type worms. Afatinib, an anti-cancer drug, protects against M22 toxicity. Afatinib by itself does not increase longevity.     

Gene co-expression network analysis for identifying genetic markers in Parkinson's disease - a three-way comparative approach

Parkinson's disease (PD) is a neurodegenerative disorder involving progressive deterioration of dopaminergic neurons. Although few genetic markers for familial PD are known, the etiology of sporadic PD remains poorly understood. Microarray data was analysed for induced pluripotent stem cells (iPSCs) derived from PD patients and mature neuronal cells (mDA) differentiated from these iPSCs. Combining expression and semantic similarity, a highly-correlated PD interactome was constructed that included interactions of established Parkinson's disease marker genes. A novel three-way comparative approach was employed, delineating topologically and functionally important genes. These genes showed involvement in pathways like Parkin-ubiquitin proteosomal system (UPS), immune associated biological processes and apoptosis. Of interest are three genes, eEF1A1, CASK, and PSMD6 that are linked to PARK2 activity in the cell and thereby form attractive candidate genes for understanding PD. Network biology approach delineated in this study can be applied to other neurodegenerative disorders for identification of important genetic regulators.     

GDF-15 promotes mitochondrial function and proliferation in neuronal HT22 cells

The neuronal cell line HT22 is an excellent model for studying Parkinson's disease. Growth differentiation factor 15 (GDF15) plays a critical role in Parkinson's disease, but the molecular mechanism involved are not well understood. We constructed the GDF15 overexpression HT22 cells and detected the effects of overexpression of GDF15 on the viability, oxygen consumption, mitochondrial membrane potential of oligomycin-treated HT22 cells. In addition, we used a high-throughput RNA-sequencing to study the lncRNA and mRNA expression profiling and obtained key lncRNAs, mRNA, gene ontology (GO), and Kyoto encyclopedia of genes and genomes (KEGG) pathway. The expression of selected DElncRNAs was validated by quantitative real-time PCR (qRT-PCR). Our results showed that overexpression of GDF15 significantly reversed the cells viability, oxygen consumption, and mitochondrial membrane potential effect caused by oligomycin in HT22 cells. The 1093 DEmRNAs and 395 DElncRNAs in HT22 cells between GDF15-oligomycin non-intervention group and a normal control-oligomycin un-intervention group were obtained, and 394 DEmRNAs and 271 DElncRNAs in HT22 cells between GDF15-oligomycin intervention group and normal control-oligomycin intervention group were identified. Base on the GO and KEGG enrichment analysis of between GDF15-oligomycin intervention group and normal control-oligomycin intervention group, positive regulation of cell proliferation was most significantly enriched GO terms, and Cav1 was enriched in positive regulation of cell proliferation pathway. PI3K-Akt signaling pathway was one significantly enriched pathway in GDF15-oligomycin intervention group. The qRT-PCR results were consistent with RNA-sequencing, generally. GDF15 might promote mitochondrial function and proliferation of HT22 cells by regulating PI3K/Akt signaling pathway. Our study may be helpful in understanding the potential molecular mechanism of GDF15 in Parkinson's disease.     

Stereoselective reactions of (20R)-3,20-dihydroxy-(3',4'-dihydro-2'H-pyranyl)-5-pregnene derivatives form 27-nor-3,20,23,26-tetrahydroxy-cholesten-22-ones and related bromo ketones

The previously reported analog of pregnenolone having a 3,4-dihydro-2H-pyran attached via a Cz.sbnd;C bond to the C-20 position (1), stereoselectively reacts with m-chloroperoxybenzoic acid in methanol at -5 degrees C. Acid-catalyzed hydrolysis of the isolated intermediates gives good yields of mostly a new 27-norcholesterol analog: (20R,23R)-3,20,23,26-tetrahydroxy-27-norcholest-5-en-22-one-3-acetate (2a, and a smaller amount of its 23S enantiomer 2b). Three different conditions of epoxidation and methanolysis followed by acid-catalyzed hydrolysis typically produce approximately 2:1 ratios of the 23R:23S diastereoisomers with a C-23 hydroxy group at the new asymmetric center. Bromine also reacts stereoselectively with (20R)-3,20-dihydroxy-(3',4'-dihydro-2'H-pyranyl)-5-pregnene (4) giving mostly (20R,23R)-23-bromo-3,20,26-trihydroxy-27-norcholest-5-en-22-one (7a). Thus both major steroidal products 2a and 7a have the same C-23R configuration. Assignment of molecular structures and the absolute configurations to 1 and 2a were based on elemental analysis, mass spectra, nuclear magnetic resonance, FTIR infrared spectroscopic analysis and X-ray crystallography. Mechanisms are discussed for stereochemical selectivity during epoxidation and bromination of the 3,4-dihydro-2H-pyranyl ring in 1 and 4.