Amantini Consuelo, Farfariello Valerio, Cardinali Claudio, Morelli Maria Beatrice, Marinelli Oliviero, Nabissi Massimo, Santoni Matteo, Bonfili Laura, Cecarini Valentina, Eleuteri Anna Maria, Santoni Giorgio
School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy.
University of Lille, INSERM U1003 - PHYCEL - Physiologie Cellulaire, Lille, France.
Oncotarget. 2017 Oct 11;8(53):90766-90780. doi: 10.18632/oncotarget.21798. eCollection 2017 Oct 31.
Autophagy and the ubiquitin-proteasome system (UPS) control thymus cell homeostasis under resting and endoplasmic reticulum (ER) stress conditions. Several evidence support a cross-talk between UPS and autophagy; abrogation of UPS responses stimulates autophagy, and vice versa the inhibition of autophagy alters the UPS functions. Herein, we found that TRPV1 activation induces ER stress, proteasome dysfunction and autophagy in thymocytes by modulating the expression of UPR-related genes. The TRPV1-mediated autophagy prevents the UPR activation by inhibiting BiP, Grp94 and ERp57 chaperone protein expression. Thymocytes from TRPV1 KO mice display both autophagy and proteasome dysfunctions, resulting in increased apoptotic cells and reduced total DP thymocyte number. In addition, positive selection of thymocytes triggered by anti-TCRβ/CD2 Ab-mediated costimulation induces apoptosis in thymocytes from TRPV1 KO as compared with WT mice. Stimulation of TRPV1 KO thymocytes with anti-TCRβ/CD2 mAbs modulates the expression of CD4 antigen on purified DP thymocytes, with reduced number of mature, single positive (SP) CD4 and increased number of immature SP CD4 and DP CD4CD8 thymocytes, further supporting the intrinsic role of TRPV1 in T cell maturation. Finally, a reduction in CD8 and CD4 T cells is evidenced in the peripheral blood and spleen of TRPV1 KO, as compared with WT mice. Therapeutic strategy by restraining or stimulating the TRPV1 expression and functions in thymocytes might represent a new pharmacological tool in the regulation of different inflammatory T cell responses.
自噬和泛素-蛋白酶体系统（UPS）在静息和内质网（ER）应激条件下控制胸腺细胞的稳态。多项证据支持UPS和自噬之间存在相互作用；UPS反应的缺失会刺激自噬，反之，自噬的抑制会改变UPS的功能。在此，我们发现TRPV1激活通过调节未折叠蛋白反应（UPR）相关基因的表达，诱导胸腺细胞发生内质网应激、蛋白酶体功能障碍和自噬。TRPV1介导的自噬通过抑制BiP、Grp94和ERp57伴侣蛋白的表达来阻止UPR激活。来自TRPV1基因敲除小鼠的胸腺细胞表现出自噬和蛋白酶体功能障碍，导致凋亡细胞增加，总双阳性（DP）胸腺细胞数量减少。此外，与野生型小鼠相比，抗TCRβ/CD2抗体介导的共刺激引发的胸腺细胞阳性选择会诱导TRPV1基因敲除小鼠的胸腺细胞凋亡。用抗TCRβ/CD2单克隆抗体刺激TRPV1基因敲除小鼠的胸腺细胞，可调节纯化的DP胸腺细胞上CD4抗原的表达，成熟的单阳性（SP）CD4细胞数量减少，未成熟的SP CD4细胞和DP CD4CD8胸腺细胞数量增加，进一步支持了TRPV1在T细胞成熟中的内在作用。最后，与野生型小鼠相比，TRPV1基因敲除小鼠的外周血和脾脏中CD8和CD4 T细胞减少。通过抑制或刺激胸腺细胞中TRPV1的表达和功能的治疗策略可能代表了一种调节不同炎症性T细胞反应的新药理学工具。
