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

目的

探讨脑源性神经营养因子（BDNF）增强间充质干细胞（MSC）抑制滤泡辅助性T细胞（Tfh细胞）的作用及机制。

方法

ELISA法检测MSC培养上清中吲哚胺2,3-二加氧酶（IDO）、IL-10、TGF-β和IL-21的含量；采集健康志愿者的外周血标本，采用人淋巴细胞分离液分离外周血中的淋巴细胞；采用Transwell小室进行MSC和淋巴细胞共培养，流式细胞术检测CD4⁺CXCR5⁺ Tfh细胞及其亚群的比例。

结果

①BDNF组（BDNF刺激的MSC）培养上清IL-10、TGF-β、IDO浓度均高于对照组（加入等体积磷酸盐缓冲液）[IL-10：（42.1±4.4）ng/ml对（19.3±2.1）ng/ml，t=4.761，P=0.009；TGF-β：（13.9±1.7）ng/ml对（5.3±0.6）ng/ml，t=5.129，P=0.008；IDO：（441.3±56.9）ng/ml对（226.7±37.6）ng/ml，t=3.130，P=0.035]；②BDNF组（淋巴细胞与BDNF刺激的MSC共培养）与MSC组（淋巴细胞与MSC共培养）比较：CD4⁺CXCR5⁺Tfh细胞比例降低[（3.37±0.21）%对（6.51±0.27）%，t=9.353，P<0.001]，CD4⁺ CXCR5⁺ CXCR3⁺ CCR6⁻Tfh1细胞比例升高[（41.14±2.04）%对（26.72±2.57）%，t=4.383，P=0.012]，CD4⁺CXCR5⁺CXCR3⁻CCR6⁻Tfh2细胞和CD4⁺CXCR5⁺CXCR3⁻CCR6⁺Tfh17细胞比例降低[Tfh2：（30.16±5.38）%对（43.26±4.11）%，t=4.426，P=0.012；Tfh17：（15.61±1.52）%对（22.32±0.72）%，t=4.202，P=0.014]，CD4⁺CXCR5⁺Foxp3⁺ Tfr细胞比例升高[（4.95±0.22）%对（2.32±0.16）%，t=10.241，P<0.001]，淋巴细胞培养上清中IL-21浓度降低[（0.28±0.03）ng/ml对（0.85±0.08）ng/ml，t=6.675，P=0.003]。

结论

BDNF能够增强MSC抑制Tfh细胞的作用，机制是抑制淋巴细胞中Tfh细胞比例升高及其向Tfh2和Tfh17亚群的分化。

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.