[Brain derived neurotrophic factor enhances the role of mesenchymal stem cells in inhibiting follicular helper T cells].

Objective: To investigate the effect of brain derived neurotrophic factor (BDNF) on mesenchymal stem cells (MSC) inhibiting follicular helper T cells (Tfh cells). Methods: The contents of indoleamine 2,3-dioxygenase (IDO), IL-10, TGF-ß and IL-21 in MSC culture supernatant were detected by ELISA; The peripheral blood of healthy volunteers were collected, and lymphocyte in peripheral blood was separated by human lymphocyte separation solution; Co-cultures of MSC and lymphocyte were performed by Transwell chamber, and the proportion of CD4(+)CXCR5(+) Tfh cells and their subtypes were detected by flow cytometry. Results: ①The concentrations of IL-10, TGF-ß, and IDO in the supernatant of BDNF group (BDNF-stimulated MSC) were higher than those of the control ones (adding PBS with the same volume) [IL-10: (42.1±4.4) ng/ml vs (19.3±2.1) ng/ml, t=4.761, P=0.009; TGF-ß: (13.9±1.7) ng/ml vs (5.3±0.6) ng/ml, t=5.129, P=0.008; IDO: (441.3±56.9) ng/ml vs (226.7±37.6) ng/ml, t=3.130, P=0.035]; ②The comparisons between BDNF (co-culture of lymphocyte and BDNF-stimulated MSC) and MSC groups (co-culture of lymphocyte and MSC) were detailed as of follows: the proportion of CD4(+) CXCR5(+)Tfh cells were lower [(3.37±0.21)% vs (6.51±0.27)%, t=9.353, P<0.001], the proportion of CD4(+) CXCR5(+)CXCR3(+) CCR6(-) Tfh cells were higher [(41.14±2.04)% vs (26.72±2.57)%, t=4.383, P=0.012], CD4(+)CXCR5(+)CXCR3(-)CCR6(-) Tfh2 cells and CD4(+)CXCR5(+)CXCR3(-)CCR6(+) Tfh17 cells were lower [Tfh2: (30.16±5.38)% vs (43.26±4.11)%, t=4.426, P=0.012; Tfh17: (15.61±1.52)% vs (22.32±0.72)%, t=4.202, P=0.014], the proportion of CD4(+)CXCR5(+)Foxp3(+) Tfr cells were higher [(4.95±0.22)% vs (2.32±0.16)%, t=10.241, P<0.001], the concentration of IL-21 in the lymphocyte supernatant was lower [(0.28±0.03) ng/ml vs (0.85±0.08) ng/ml, t=6.675, P=0.003]. Conclusion: BDNF could enhance the inhibitory effect of MSC on Tfh cells through inhibiting the increasing of Tfh cells and the differentiations of Tfh2 and Tfh17 cells.

The J domain of Tpr2 regulates its interaction with the proapoptotic and cell-cycle checkpoint protein, Rad9.

Human Rad9 is a key cell-cycle checkpoint protein that is postulated to function in the early phase of cell-cycle checkpoint control through complex formation with Rad1 and Hus1. Rad9 is also thought to be involved in controlling apoptosis through its interaction with Bcl-2. To explore the biochemical functions of Rad9 in these cellular control mechanisms, we performed two-hybrid screening and identified Tetratricopeptide repeat protein 2 (Tpr2) as a novel Rad9-binding protein. We found that Tpr2 binds not only to Rad9, but also to Rad1 and Hus1, through its N-terminal tetratricopeptide repeat region, as assessed by in vivo and in vitro binding assays. However, the in vivo and in vitro interactions of Tpr2 with Rad9 were greatly enhanced by the deletion of its C-terminal J domain or by a point mutation in the conserved HPD motif in the J domain, though the binding of Tpr2 to Rad1 and Hus1 was not influenced by these J-domain mutations. We further found: (1) Rad9 transiently dissociates from Tpr2 following heat-shock or UV treatments, but the mutation of the J domain abrogates this transient dissociation of the Tpr2/Rad9 complex; and (2) the J domain of Tpr2 modulates the cellular localization of both Tpr2 itself and Rad9. These results indicate that the J domain of Tpr2 plays a critical role in the regulation of both physical and functional interactions between Tpr2 and Rad9.

Transdermal delivery of metoprolol. II: In-vitro skin permeation and bioavailability in hairless rats.

The absolute bioavailability of metoprolol (MP) was evaluated following oral and transdermal administration in hairless rats. The absolute bioavailability of MP following oral administration was 3.48 +/- 1.73%, indicating that MP is subject to extensive hepatic first-pass metabolism. Transdermal delivery of MP, via an adhesive delivery device, resulted in a bioavailability of 30.07 +/- 4.84%, indicating that the transdermal delivery of MP can significantly increase systemic bioavailability compared with oral administration. Preliminary skin irritation studies indicated that neither MP nor the adhesive used in the device caused any appreciable skin irritation in the hairless rats.