tacrolimus and epigallocatechin-gallate

Epigallocatechin-3-gallate (EGCG) is the most biologically active catechin of green tea. Tacrolimus (TAC) and cyclosporine A (CsA) are immunosuppressive agents commonly used in clinical organ transplantation. The present study investigated the effect of EGCG on the pharmacokinetics of TAC and CsA in rats and its underlying mechanisms.. Either TAC or CsA was administered to rats intravenously or orally with or without concomitant EGCG. Polymerase Chain Reaction and Western Blot were used to determine the effect of EGCG on drug-metabolizing enzymes (DMEs), drug transporters (DTs) and nuclear receptors (NRs).. These results revealed consumption of high dose EGCG may cause a significant alteration in pharmacokinetics of TAC and distribution/elimination profiles of CsA through the regulation of DMEs, DTs and NRs.

Topics: Administration, Intravenous; Administration, Oral; Animals; Area Under Curve; Calcineurin Inhibitors; Catechin; Cyclosporine; Dose-Response Relationship, Drug; Herb-Drug Interactions; Immunosuppressive Agents; Male; Rats; Rats, Sprague-Dawley; Tacrolimus

Alpha-synuclein (αSYN) aggregation plays a pivotal role in the pathogenesis of Parkinson's disease and other synucleinopathies. In this multistep process, oligomerization of αSYN monomers is the first step in the formation of fibrils and intracytoplasmic inclusions. Although αSYN oligomers are generally considered to be the culprit of these diseases, the methodology currently available to follow-up oligomerization in cells and in brain is inadequate. We developed a split firefly luciferase complementation system to visualize oligomerization of viral vector-encoded αSYN fusion proteins. αSYN oligomerization resulted in successful luciferase complementation in cell culture and in mouse brain. Oligomerization of αSYN was monitored noninvasively with bioluminescence imaging in the mouse striatum and substantia nigra up to 8 months after injection. Moreover, the visualized αSYN oligomers retained their toxic and aggregation properties in both model systems. Next, the effect of two small molecules, FK506 and (-)-epigallocatechin-3-gallate (EGCG), known to inhibit αSYN fibril formation, was investigated. FK506 inhibited the observed αSYN oligomerization both in cell culture and in mouse brain. In conclusion, the split firefly luciferase-αSYN complementation assay will increase our insight in the role of αSYN oligomers in synucleinopathies and opens new opportunities to evaluate potential αSYN-based neuroprotective therapies.

Topics: alpha-Synuclein; Animals; Catechin; Cell Death; Cells, Cultured; Corpus Striatum; Dopaminergic Neurons; Humans; Luciferases, Firefly; Luminescent Measurements; Mice; Neuroimaging; Neuroprotective Agents; Protein Aggregates; Substantia Nigra; Tacrolimus

FK506 (tacrolimus) is a widely used immunosuppressant first employed in the management of rejection in organ transplantation, but now used for autoimmune disease. However, the nephrotoxicity induced by FK506 remains a serious clinical problem. We previously demonstrated that FK506 caused a significant increase in apoptosis of LLC-PK1 cells, a porcine proximal tubule cell line, but the addition of green tea extract and its polyphenolic components suppressed the cell death. Here, we examined the synergistic effect of tea polyphenols on the protection of FK506-induced cell death. The combined treatment with 5 microM (-)-epigallocatechin-gallate (EGCG) and 5 microM of (+)-catechin (C), (-)-epicatechin (EC), (-)-epigallocatechin (EGC) or (-)-epicatechin-gallate (ECG) reduced FK506-induced cytotoxicity in LLC-PK1. Similarly, the combined treatment with 5 microM EGC and 5 microM of C, EC, EGCG or ECG also reduced the cytotoxicity. These results showed that the co-treatments with EGCG and EGC, EGCG or ECG, and EGC and ECG have stronger synergistic effects on the protection of FK506-induced cell death. Furthermore, the combined treatment of EGCG (5 microM) and EGC (5 microM) showed a significant time-dependent suppression of the increased intracellular ROS levels 15 min after the addition of FK506, as well as on caspase activation. The results of these synergistic effects of the constituents of green tea extract suggest that its protective effects may reside in more than just one of its constituent.

Topics: Animals; Apoptosis; Beverages; Caspase 3; Catechin; Cell Line; Cell Survival; Drug Synergism; Flavonoids; Immunosuppressive Agents; Kidney Tubules, Proximal; Phenols; Polyphenols; Reactive Oxygen Species; Swine; Tacrolimus

Epigallocatechin-3-gallate (EGCG) has been shown to exert anti-inflammatory effects on the inflammatory skin conditions. However, little is known about its effect on atopic dermatitis (AD). We first attempted to assess the anti-inflammatory effect of topical application of EGCG in vivo AD model using NC/Nga mice and to determine whether EGCG exerts the anti-inflammatory effect by inhibiting macrophage migration inhibitory factor (MIF) and other cytokines that are related to immune dysregulation in the pathogenesis of AD. Murine AD-like skin lesions were made by painting Dermatophagoides pteronissinus extract (DPE). The effects of EGCG treatment were assessed by total clinical severity score and ear thickness, and by histological grading. In addition, the mRNA and protein expression of the cytokines including MIF were measured by real-time RT-PCR and immunohistochemistry. The serum levels of MIF and IgE were measured by ELISA. In the AD mouse model, EGCG significantly reduced the total clinical severity score and ear thickness (p<0.05). The histological grading was also markedly improved. The mRNA expression of MIF, TNF-alpha, IFN-gamma, IL-2 and IL-12 p40, but not of IL-4, IL-5 and IL-13 in the lesions was significantly reduced by EGCG (p<0.05). On the immunohistochemistry, EGCG also markedly diminished the expression of MIF, TNF-alpha and IFN-gamma. The serum MIF and IgE production was significantly reduced by EGCG (p<0.05). These results demonstrate that topical application of EGCG may improve the AD-like skin lesions by suppressing MIF and T helper 1 cytokines. Taken together, it is suggested that EGCG may be a potential therapeutic modality for AD.

Topics: Animals; Antigens, Dermatophagoides; Catechin; Cytokines; Dermatitis, Atopic; Ear, External; Enzyme-Linked Immunosorbent Assay; Female; Immunohistochemistry; Immunosuppressive Agents; Macrophage Migration-Inhibitory Factors; Mice; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Skin; Tacrolimus