Colombo Gualtiero, Sordi Andrea, Lonati Caterina, Carlin Andrea, Turcatti Flavia, Leonardi Patrizia, Gatti Stefano, Catania Anna
Center for Preclinical Investigation, Fondazione IRCCS Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena, Via F.Sforza 35, Milano 20122, Italy.
Brain Behav Immun. 2008 Aug;22(6):817-23. doi: 10.1016/j.bbi.2007.11.009. Epub 2008 Jan 4.
Prevention of graft dysfunction is a major objective in transplantation medicine. Previous research on experimental heart transplantation indicated that treatment with the immunomodulatory peptide alpha-melanocyte stimulating hormone (alpha-MSH) improves histopathology, prolongs allograft survival, and reduces expression of the main tissue injury mediators. Because calcium-handling is critical in heart graft function, we determined the effects of transplantation injury and influences of alpha-MSH treatment on representative calcium regulatory proteins in rat heart allografts. Hearts from Brown Norway rats were transplanted heterotopically into MHC incompatible Lewis rats. Ca(2+)/calmodulin-dependent protein kinase II (CaMKII), protein kinase C epsilon (PKC epsilon), sarcoplasmic/endoplasmic reticulum calcium-ATPase 2 (SERCA2a), arrestin-beta1 (Arrb1), cholinergic receptor M2 (Chrm2), and inositol 1,4,5-triphosphate receptor 1 (InsP(3)R1) were examined in: (1) non-transplanted donor hearts; (2) allografts from saline-treated rats; and (3) allografts from rats treated with the synthetic alpha-MSH analog Nle4-DPhe7-alpha-MSH (NDP-alpha-MSH) (100 microg i.p. every 12h). Transplantation injury was associated with severe reduction in calcium regulatory protein transcription and expression level. NDP-alpha-MSH administration partly reversed inhibition of protein transcription and almost completely prevented protein loss. Finally, because certain effects of cyclic 3'-5'-adenosine monophosphate (cAMP) signaling on calcium handling in cardiac myocytes depend on activation of exchange protein directly activated by cAMP 1 (Epac1), we determined Epac1 mRNA and protein expression in heart allografts. Transplantation injury markedly reduced Epac1. NDP-alpha-MSH treatment significantly preserved both Epac1 protein and mRNA in the allografts. Administration of alpha-MSH or related melanocortins could reduce transplantation-induced dysfunction through protection of heart calcium regulatory proteins.
预防移植物功能障碍是移植医学的主要目标。先前对实验性心脏移植的研究表明，用免疫调节肽α-黑素细胞刺激素（α-MSH）治疗可改善组织病理学、延长同种异体移植物存活时间并降低主要组织损伤介质的表达。由于钙处理对心脏移植物功能至关重要，我们确定了移植损伤的影响以及α-MSH治疗对大鼠心脏同种异体移植物中代表性钙调节蛋白的影响。将来自棕色挪威大鼠的心脏异位移植到MHC不相容的刘易斯大鼠体内。在以下情况中检测了钙/钙调蛋白依赖性蛋白激酶II（CaMKII）、蛋白激酶Cε（PKCε）、肌浆网/内质网钙ATP酶2（SERCA2a）、抑制蛋白β1（Arrb1）、胆碱能受体M2（Chrm2）和肌醇1,4,5-三磷酸受体1（InsP(3)R1）：（1）未移植的供体心脏；（2）盐水处理大鼠的同种异体移植物；（3）用合成α-MSH类似物Nle4-DPhe7-α-MSH（NDP-α-MSH）（每12小时腹腔注射100微克）处理大鼠的同种异体移植物。移植损伤与钙调节蛋白转录和表达水平的严重降低有关。给予NDP-α-MSH部分逆转了对蛋白质转录的抑制，并几乎完全防止了蛋白质丢失。最后，由于环磷酸腺苷（cAMP）信号对心肌细胞钙处理的某些作用取决于直接由cAMP 1激活的交换蛋白（Epac1）的激活，我们测定了心脏同种异体移植物中Epac1的mRNA和蛋白表达。移植损伤显著降低了Epac1。NDP-α-MSH治疗显著保留了同种异体移植物中的Epac1蛋白和mRNA。给予α-MSH或相关黑素皮质素可通过保护心脏钙调节蛋白来减少移植诱导的功能障碍。
