1.The Synergistic Local Immunosuppressive Effects of Neural Stem Cells Expressing Indoleamine 2,3-Dioxygenase (IDO) in an Experimental Autoimmune Encephalomyelitis (EAE) Animal Model.
Lee YE1,2, An J2, Lee KH1,2, Kim SS1,2, Song HJ3,2, Pyeon H3,2, Nam H2, Kang K3, Joo KM1,3,4. PLoS One. 2015 Dec 4;10(12):e0144298. doi: 10.1371/journal.pone.0144298. eCollection 2015.
Neurodegenerative diseases provoke robust immunological reactions in the central nervous system (CNS), which further deteriorate the neural tissue damage. We hypothesized that the expression levels of indoleamine 2,3-dioxygenase (IDO), an enzyme that has potent immune suppressive activities, in neural stem cells (NSCs) would have synergistic therapeutic effects against neurodegenerative diseases, since NSCs themselves have low IDO expression. In this study, the synergistic immune suppressive effects of rat fetal NSCs expressing IDO (rfNSCs-IDO) were validated by mixed leukocyte reaction (MLR) in vitro and an experimental autoimmune encephalomyelitis (EAE) animal model in vivo. rfNSCs-IDO showed significantly more suppressive effects on T cell proliferation in the MLR compared to control rfNSCs (rfNSCs-Cont). Importantly, IDO inhibition using 1-methyl-DL-tryptophan (1-MT), an IDO inhibitor, reversed the synergistic effects, confirming IDO-specific effects in rfNSCs-IDO.
2.An artificial self-sufficient cytochrome P450 directly nitrates fluorinated tryptophan analogs with a different regio-selectivity.
Zuo R1, Zhang Y1, Huguet-Tapia JC2, Mehta M1, Dedic E1, Bruner SD3,4, Loria R2, Ding Y5,6. Biotechnol J. 2016 Jan 7. doi: 10.1002/biot.201500416. [Epub ahead of print]
Aromatic nitration is an immensely important industrial process to produce chemicals for a variety of applications, but often suffers from multiple unsolved challenges. Enzymes as biocatalysts have been increasingly used for organic chemistry synthesis due to their high selectivity and environmental friendliness, but nitration has benefited minimally from the development of biocatalysis. In this work, we aimed to develop TxtE as practical biocatalysts for aromatic nitration. TxtE is a unique class I cytochrome P450 enzyme that nitrates the indole of L-tryptophan. To develop cost-efficient nitration processes, we fused TxtE with the reductase domains of CYP102A1 (P450BM3) and of P450RhF to create class III self-sufficient biocatalysts. The best engineered fusion protein was comparable with wild type TxtE in terms of nitration performance and other key biochemical properties. To demonstrate the application potential of the fusion enzyme, we nitrated 4-F-DL-tryptophan and 5-F-L-tryptophan in large scale enzymatic reactions.
3.Effect of the association of 1-methyl-DL-tryptophan with paclitaxel on the expression of indoleamine 2,3-dioxygenase in cultured cancer cells from patients with breast cancer.
Salvadori ML1, da Cunha Bianchi PK1, Gebrim LH2, Silva RS1, Kfoury JR Jr3. Med Oncol. 2015 Nov;32(11):248. doi: 10.1007/s12032-015-0694-8. Epub 2015 Oct 6.
Breast cancer is the most common type of cancer among women and the survival of patients affected by it is increasing, mainly due to several new approaches in early diagnosis and more effective treatments. The enzyme indoleamine 2,3-dioxygenase (IDO) is expressed in many cells, including tumor cells. IDO acts by inhibiting the proliferation of T lymphocytes, thus compromising their cytotoxic activity. 1-Methyl-DL-tryptophan (1MT) is a competitive inhibitor of IDO, which blocks its immunosuppressive effect. Paclitaxel is an antineoplastic drug largely used in breast cancer therapy. Thus, this study aimed to determine the in vitro effect of the association of 1MT and paclitaxel chemotherapy, as an approach to reduce tumor growth. It is believed that this would allow the restoration of T lymphocyte proliferation capability and its cytotoxic response. The supplemented cultures showed that the most significant differences in the expression of IDO were observed in the group treated with paclitaxel associated with 1-MT continuous supplementation, reducing enzyme expression from 12.
4.Assessment of chemical exchange in tryptophan-albumin solution through (19)F multicomponent transverse relaxation dispersion analysis.
Lin PC1. J Biomol NMR. 2015 Jun;62(2):121-7. doi: 10.1007/s10858-015-9929-4. Epub 2015 Apr 22.
A number of NMR methods possess the capability of probing chemical exchange dynamics in solution. However, certain drawbacks limit the applications of these NMR approaches, particularly, to a complex system. Here, we propose a procedure that integrates the regularized nonnegative least squares (NNLS) analysis of multiexponential T2 relaxation into Carr-Purcell-Meiboom-Gill (CPMG) relaxation dispersion experiments to probe chemical exchange in a multicompartmental system. The proposed procedure was validated through analysis of (19)F T2 relaxation data of 6-fluoro-DL-tryptophan in a two-compartment solution with and without bovine serum albumin. Given the regularized NNLS analysis of a T2 relaxation curve acquired, for example, at the CPMG frequency υ CPMG = 125, the nature of two distinct peaks in the associated T2 distribution spectrum indicated 6-fluoro-DL-tryptophan either retaining the free state, with geometric mean */multiplicative standard deviation (MSD) = 1851.
