García-Sanmartín Josune, Narro-Íñiguez Judit, Puente María José, Cuttitta Frank, Martínez Alfredo
Angiogenesis Group, Center for Biomedical Research of La Rioja (CIBIR), 26006, Logroño, Spain.
Obstetrics Department, San Pedro University Hospital, 26006, Logroño, Spain.
Sci Rep. 2025 Aug 20;15(1):30497. doi: 10.1038/s41598-025-14201-x.
Cripto-1 (CR1) is an oncofetal protein involved in EGF/TGFβ signal transduction, with important functions in development, stem cell biology and cancer. Its homolog, Cripto-3 (CR3), is almost identical, with the exception of six (out of 188) amino acids. Thus, until recently, no antibody could distinguish them. Here, we compare the immunostaining pattern for highly specific monoclonal antibodies against CR1 and CR3 in human samples of placenta, umbilical cord and fetal tissues. Immunoreactivity (IR) for both proteins was found in placenta, umbilical cord, fetal retina, testis, lung, esophagus, pancreas and kidney, but was absent in samples of fetal heart, brain, liver and thymus. Nevertheless, a very different staining pattern emerged for CR1 and CR3 in the positive tissues. For instance, (i) CR1-IR in the placenta, umbilical cord and fetal esophagus was preferently found in cell nuclei whereas CR3-IR was always cytoplasmic; (ii) In endothelial cells, CR1 staining was always stronger than CR3´s; (iii) In the retina and the testes, CR3-IR was stronger than CR1´s in Müller cells and fetal spermatogonias; (iv) The epithelium of the fetal bronchioles was very faint for CR1 and strongly positive for CR3; and (v) Both CR1 and CR3 stained the fetal pancreatic islets, but CR1-IR was stronger than CR3´s in the peripheral cells of the islets. All these morphological differences in staining pattern point to complex nuances in Cripto biology that were not evident previously, including the nuclear localization of CR1, and these need to be addressed through molecular and physiological approaches.
Cripto-1（CR1）是一种参与表皮生长因子/转化生长因子β信号转导的癌胚蛋白，在发育、干细胞生物学和癌症中具有重要功能。其同源物Cripto-3（CR3）几乎完全相同，仅有188个氨基酸中的6个不同。因此，直到最近，还没有抗体能够区分它们。在这里，我们比较了针对CR1和CR3的高度特异性单克隆抗体在人胎盘、脐带和胎儿组织样本中的免疫染色模式。在胎盘、脐带、胎儿视网膜、睾丸、肺、食管、胰腺和肾脏中均发现了这两种蛋白的免疫反应性（IR），但在胎儿心脏、大脑、肝脏和胸腺样本中未发现。然而，在阳性组织中，CR1和CR3呈现出非常不同的染色模式。例如，（i）在胎盘、脐带和胎儿食管中，CR1免疫反应性优先出现在细胞核中，而CR3免疫反应性总是出现在细胞质中；（ii）在内皮细胞中，CR1染色总是比CR3更强；（iii）在视网膜和睾丸中，在米勒细胞和胎儿精原细胞中，CR3免疫反应性比CR1更强；（iv）胎儿细支气管上皮对CR1染色非常微弱，对CR3呈强阳性；（v）CR1和CR3都对胎儿胰岛染色，但在胰岛外周细胞中，CR1免疫反应性比CR3更强。染色模式的所有这些形态学差异都表明Cripto生物学中存在复杂的细微差别，这些差别以前并不明显，包括CR1的核定位，需要通过分子和生理学方法来解决。
