Anti-Beta Galactosidase polyclonal antibody [FITC]

Background Stem cell senescence has been proposed as one of the major drivers of aging, and MSC senescence contributes to aging-related diseases. Activation of mTORC1 pathway and heterochromatin organization have been characterized as two characteristics of senescent cells; however, whether mTORC1 pathway interacts with heterochromatin organization and contributes to MSC senescence remains unknown. In this study, we investigated the interaction between heterochromatin organization and mTORC1/p70S6K pathway in stress-induced MSC senescence. Methods The stress-induced senescence models were established in human umbilical cord-derived MSCs by doxorubicin (Dox) or H2O2. Cellular senescence was evaluated by beta-Gal activity, upregulation of cell cycle suppressor genes, and expression of SASP. Activation of heterochromatin organization and mTORC1 pathway was determined by Western blot and immunofluorescent staining. A D-galactose (D-Gal)-induced aging model was established in rats to evaluate the crosstalk between heterochromatin and mTORC1 pathway in vivo. Results We found that heterochromatin organization was provoked at the early stage of Dox- or H2O2-induced senescence. Disruption of heterochromatin organization led to robust DNA damage response and exacerbated cellular senescence. Suppression of mTORC1/p70S6K pathway by either rapamycin or p70S6K knockdown promoted heterochromatin organization and ameliorated Dox- or H2O2-induced DNA damage and senescence. In contrast, direct activation of mTORC1 by MHY1485 impaired heterochromatin organization and aggravated stress-induced senescence. Moreover, concomitant activation of mTORC1 pathway and heterochromatin organization was found in D-galactose-induced osteoporosis model in rats. Rapamycin alleviated cellular senescence and promoted heterochromatin organization in BMSCs derived from D-galactose-treated rats. Conclusions Altogether, our study indicates the existence of a complex interplay between the mTORC1/p70S6K pathway and the heterochromatin organization during stress-induced MSC senescence, with important implications for the understanding of aging as well as for its prevention and treatment.

environmental protocols for their preparation carrying defined oligosaccharides remains a big challenge due to lack of access to structurally well-defined and functionalized oligosaccharides. In this work a highly sustainable and efficient chemoenzymatic synthesis of neo-glycoproteins in green solvents was studied. In particular, we described the preparation of new activated disaccharides useful for direct protein binding under mild reaction conditions, reducing the protection/activation steps commonly needed in the traditional synthetic routes. Thus, N-acetylglucosamine (GlcNAc) was functionalized with a thiocyanomethyl group at C-1 and employed for the first time as acceptor in the enzymatic synthesis of the disaccharide of interest using beta-Gal-3 from Bacillus circulans and beta-galactosidase from Escherichia coli. The use of biosolvents promotes a very important increase of the enzymatic activity in the synthesis of functionalized Gal-beta-(1 -> 6)-GlcNAc (95%) preventing hydrolytic activity with full regioselectivity. Furthermore, reaction scaling up and biosolvent recycling are feasible without losing catalytic action. The enzyme-substrate recognition and the effect of biosolvent over the galactosidases activity has been investigated and explained by computational modeling studies. The presence of C-1 thiocyanomethyl moiety strongly hindered the normal course of transglycosylation for beta-Gal-3 afforded beta(1 -> 6) glyosidic linkage instead of beta(1 -> 3). Then, this functionalized disaccharide has been activated with imino methoxyethyl (IME) linker and conjugated to ribonuclease A (RNase A). The glycosylation of RNase A, with IME-disaccharide provided the corresponding neo-glycoprotein with 85% of yield. This work opens to a new, simple, and green way to synthesize innovative glycoconjugate vaccines.