1. (R)-α-lipoyl-glycyl-L-prolyl-L-glutamyl dimethyl ester codrug as a multifunctional agent with potential neuroprotective activities
Ivana Cacciatore, et al. ChemMedChem. 2012 Nov;7(11):2021-9. doi: 10.1002/cmdc.201200320. Epub 2012 Sep 13.
The (R)-α-lipoyl-glycyl-L-prolyl-L-glutamyl dimethyl ester codrug (LA-GPE, 1) was synthesized as a new multifunctional drug candidate with antioxidant and neuroprotective properties for the treatment of neurodegenerative diseases. Physicochemical properties, chemical and enzymatic stabilities were evaluated, along with the capacity of LA-GPE to penetrate the blood-brain barrier (BBB) according to an in vitro parallel artificial membrane permeability assay for the BBB. We also investigated the potential effectiveness of LA-GPE against the cytotoxicity induced by 6-hydroxydopamine (6-OHDA) and H2O2 on the human neuroblastoma cell line SH-SY5Y by using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay. Our results show that codrug 1 is stable at both pH 1.3 and 7.4, exhibits good lipophilicity (log P=1.51) and a pH-dependent permeability profile. Furthermore, LA-GPE was demonstrated to be significantly neuroprotective and to act as an antioxidant against H2O2- and 6-OHDA-induced neurotoxicity in SH-SY5Y cells.
2. LAMP2 regulates autophagy in the thymic epithelium and thymic stroma-dependent CD4 T cell development
Pedro M Rodrigues, et al. Autophagy. 2023 Feb;19(2):426-439. doi: 10.1080/15548627.2022.2074105. Epub 2022 May 19.
Within the thymus, thymic epithelial cells (TECs) provide dedicated thymic stroma microenvironments for T cell development. Because TEC functionality is sensitive to aging and cytoablative therapies, unraveling the molecular elements that coordinate their thymopoietic role has fundamental and clinical implications. Particularly, the selection of CD4 T cells depends on interactions between TCRs expressed on T cell precursors and self-peptides:MHC II complexes presented by cortical TECs (cTECs). Although the macroautophagy/autophagy-lysosomal protein degradation pathway is implicated in CD4 T cell selection, the molecular mechanism that controls the generation of selecting MHC II ligands remains elusive. LAMP2 (lysosomal-associated membrane protein 2) is a well-recognized mediator of autolysosome (AL) maturation. We showed that LAMP2 is highly expressed in cTECs. Notably, genetic inactivation of Lamp2 in thymic stromal cells specifically impaired the development of CD4 T cells that completed positive selection, without misdirecting MHC II-restricted cells into the CD8 lineage. Mechanistically, defects in autophagy in lamp2-deficient cTECs were linked to alterations in MHC II processing, which was associated with a marked reduction in CD4 TCR repertoire diversity selected within the lamp2-deficient thymic stroma. Together, our findings suggest that LAMP2 interconnects the autophagy-lysosomal axis and the processing of selecting self-peptides:MHC II complexes in cTECs, underling its implications for the generation of a broad CD4 TCR repertoire.
3. Esterification of reduced glutathione
P K Thornalley Biochem J. 1991 Apr 15;275 ( Pt 2)(Pt 2):535-9. doi: 10.1042/bj2750535.
GSH monoethyl ester [gamma-L-glutamyl-L-cysteinyl(ethyl glycinate)] may be used to supplement cellular pools of GSH in vitro and in vivo. The compound was prepared by esterification of GSH in anhydrous ethanol with HCl as the catalyst. However, a full analysis of products from the esterification of GSH revealed the formation of minor products: gamma-L-(ethyl glutamyl)-L-cysteinylglycine, i.e. an isomeric monoester, gamma-L-(ethyl glutamyl)-L-cysteinyl(ethyl glycinate), i.e. GSH diethyl ester, and N-(3-amino-2,6-dioxopiperazino)-L-cysteinyl(ethyl glycinate), i.e. an acid-catalysed cyclization product. These compounds were separated and purified by reverse-phase h.p.l.c. Esterification of GSH produces mainly the glycyl monoester with minor products of gamma-glutamyl ester, diester and the cyclization product. Only analytical reverse-phase h.p.l.c. of the compounds was found to resolve these products.
