Nakano Eriko, Geisz Andrea, Masamune Atsushi, Niihori Tetsuya, Hamada Shin, Kume Kiyoshi, Kakuta Yoichi, Aoki Yoko, Matsubara Yoichi, Ebert Karolin, Ludwig Maren, Braun Markus, Groneberg David A, Shimosegawa Tooru, Sahin-Tóth Miklós, Witt Heiko
Division of Gastroenterology, Tohoku University Graduate School of Medicine, Sendai, Japan;
Department of Molecular and Cell Biology, Boston University Henry M. Goldman School of Dental Medicine, Boston, Massachusetts;
Am J Physiol Gastrointest Liver Physiol. 2015 Oct 15;309(8):G688-94. doi: 10.1152/ajpgi.00241.2015. Epub 2015 Aug 27.
Genetic alterations in the carboxypeptidase A1 gene (CPA1) are associated with early onset chronic pancreatitis (CP). Besides CPA1, there are two other human pancreatic carboxypeptidases (CPA2 and CPB1). Here we examined whether CPA2 and CPB1 alterations are associated with CP in Japan and Germany. All exons and flanking introns of CPA2 and CPB1 were sequenced in 477 Japanese patients with CP (234 alcoholic, 243 nonalcoholic) and in 497 German patients with nonalcoholic CP by targeted next-generation sequencing and/or Sanger sequencing. Secretion and enzymatic activity of CPA2 and CPB1 variants were determined after transfection into HEK 293T cells. We identified six nonsynonymous CPA2 variants (p.V67I, p.G166R, p.D168E, p.D173H, p.R237W, and p.G388S), eight nonsynonymous CPB1 alterations (p.S65G, p.N120S, p.D172E, p.R195H, p.D208N, p.F232L, p.A317V, and p.D364Y), and one splice-site variant (c.687+1G>T) in CPB1. Functional analysis revealed essentially complete loss of function in CPA2 variants p.R237W and p.G388S and CPB1 variants p.R110H and p.D364Y. None of the CPA2 or CPB1 variants, including those resulting in a marked loss of function, were overrepresented in patients with CP. In conclusion, CPA2 and CPB1 variants are not associated with CP.
羧肽酶A1基因（CPA1）的遗传改变与早发性慢性胰腺炎（CP）相关。除了CPA1，还有另外两种人类胰腺羧肽酶（CPA2和CPB1）。在此，我们研究了CPA2和CPB1的改变在日本和德国是否与CP相关。通过靶向二代测序和/或桑格测序，对477例日本CP患者（234例酒精性，243例非酒精性）和497例德国非酒精性CP患者的CPA2和CPB1的所有外显子及侧翼内含子进行了测序。将CPA2和CPB1变体转染到HEK 293T细胞后，测定其分泌和酶活性。我们在CPB1中鉴定出6个CPA2非同义变体（p.V67I、p.G166R、p.D168E、p.D173H、p.R237W和p.G388S）、8个CPB1非同义改变（p.S65G、p.N120S、p.D172E、p.R195H、p.D208N、p.F232L、p.A317V和p.D364Y）以及1个剪接位点变体（c.687+1G>T）。功能分析显示，CPA2变体p.R237W和p.G388S以及CPB1变体p.R110H和p.D364Y的功能基本完全丧失。包括那些导致功能明显丧失的变体在内，CPA2或CPB1变体在CP患者中均未过度出现。总之，CPA2和CPB1变体与CP无关。
