Department of Pediatrics and Adolescent Medicine, Haukeland University Hospital.
Center for Diabetes Research, Department of Clinical Science, University of Bergen.
Eur J Gastroenterol Hepatol. 2021 Jun 1;33(6):839-843. doi: 10.1097/MEG.0000000000001963.
The hybrid allele of the carboxyl ester lipase gene (CEL-HYB1) is a genetic risk factor for chronic pancreatitis (CP) although the mechanism promoting disease development is largely unknown. Here, we aimed to clinically describe subjects carrying the CEL-HYB1 allele and to elucidate why the protein product is pathogenic by analyzing pancreatic secretions and cellular models.
Norwegian cases (n = 154) diagnosed with recurrent acute pancreatitis or CP were subjected to genetic screening by a CEL-HYB1-specific PCR assay followed by Sanger sequencing. For investigation of CEL-HYB1 protein secretion, duodenal juice samples from cases and controls were analyzed by western blotting. HEK293cells were transfected with constructs expressing CEL-HYB1 or the normal CEL protein (CEL-WT) and analyzed by qPCR, cell fractionation and western blotting.
Two CEL-HYB1-positive families were identified. In both pedigrees, CEL-HYB1 did not fully co-segregate with disease. One proband had recurrent acute pancreatitis and was an active smoker. Her mother was a CEL-HYB1 carrier who had suffered from several attacks of acute pancreatitis until she stopped smoking. The other proband was diagnosed with CP and pancreas divisum. Her CEL-HYB1-positive parent was symptom-free but exhibited pancreatic imaging changes. When analyzing the CEL protein in duodenal juice, CEL-WT was readily detectable but no band corresponding to the risk variant was seen. In CEL-HYB1-transfected cells, we observed impaired protein secretion, protein aggregation and endoplasmic reticulum stress.
Our data suggest that CEL-HYB1, in combination with well-known pancreatitis risk factors, causes disease through the misfolding-dependent pathway of genetic CP risk.
羧基酯脂肪酶基因（CEL-HYB1）的杂合等位基因是慢性胰腺炎（CP）的遗传风险因素，尽管导致疾病发展的机制在很大程度上尚不清楚。在这里，我们旨在通过分析胰腺分泌物和细胞模型，对携带 CEL-HYB1 等位基因的患者进行临床描述，并阐明该蛋白产物为何具有致病性。
对挪威诊断为复发性急性胰腺炎或 CP 的病例（n=154）进行了 CEL-HYB1 特异性 PCR 检测，随后进行 Sanger 测序。为了研究 CEL-HYB1 蛋白的分泌，通过 Western blot 分析了病例和对照的十二指肠液样本。用表达 CEL-HYB1 或正常 CEL 蛋白（CEL-WT）的构建体转染 HEK293 细胞，并通过 qPCR、细胞分离和 Western blot 进行分析。
鉴定出了两个 CEL-HYB1 阳性家族。在两个家系中，CEL-HYB1 并未完全与疾病共分离。一位先证者患有复发性急性胰腺炎，且是一名吸烟者。她的母亲是 CEL-HYB1 携带者，曾多次发作急性胰腺炎，直到戒烟后才有所缓解。另一位先证者被诊断为 CP 和胰腺分裂。其 CEL-HYB1 阳性的父母无症状，但表现出胰腺影像学改变。在十二指肠液中分析 CEL 蛋白时，可轻易检测到 CEL-WT，但未见与风险变异体相对应的条带。在 CEL-HYB1 转染的细胞中，我们观察到蛋白分泌受损、蛋白聚集和内质网应激。
我们的数据表明，CEL-HYB1 与已知的胰腺炎风险因素共同作用，通过遗传 CP 风险的错误折叠相关途径导致疾病。
