{"id":1153,"date":"2025-11-21T13:24:34","date_gmt":"2025-11-21T13:24:34","guid":{"rendered":"http:\/\/sebigec.es\/blog\/?guid=d31f09a462170e539baaaed8ddec26bf"},"modified":"2025-11-21T13:24:34","modified_gmt":"2025-11-21T13:24:34","slug":"development-of-a-functional-assay-for-the-characterisation-of-smad4-variants-from-the-french-haemorrhagic-hereditary-telangiectasia-cohort","status":"publish","type":"post","link":"https:\/\/sebigec.es\/blog\/index.php\/2025\/11\/21\/development-of-a-functional-assay-for-the-characterisation-of-smad4-variants-from-the-french-haemorrhagic-hereditary-telangiectasia-cohort\/","title":{"rendered":"Development of a functional assay for the characterisation of SMAD4 variants from the French haemorrhagic hereditary telangiectasia cohort"},"content":{"rendered":"\n<sec><st>Background<\/st>\n<p>Hereditary haemorrhagic telangiectasia (HHT) and juvenile polyposis syndrome (JPS) can be caused by <I>SMAD4<\/I> pathogenic variants. SMAD4 is a common transcription factor of the BMP\/TGF&beta; signalling pathway. In this study, we developed a cell-based functional assay to address the pathogenicity of <I>SMAD4<\/I> variants identified in the French HHT cohort.<\/p>\n<\/sec>\n<sec><st>Methods<\/st>\n<p>  <I>SMAD4<\/I> variants were generated by site-directed mutagenesis. A functional assay was developed in a cell line that does not express SMAD4, and the different <I>SMAD4<\/I> variants were tested for their capacity to activate the BMP and TGF&beta; response using luciferase reporter assays.<\/p>\n<\/sec>\n<sec><st>Results<\/st>\n<p>Twelve <I>SMAD4<\/I> variants were identified and studied. We were able to develop a robust functional assay for these variants. All the expressed variants resulted in loss of function (LOF) in response to BMP9 or TGF&beta;1 stimulation. <I>SMAD4<\/I> variants within the MH2 domain expressed SMAD4 mutated proteins that were unable to hetero-oligomerise with other SMADs, which could explain their LOF. Finally, we tested primary human endothelial cells isolated from patients with HHT carrying <I>SMAD4<\/I> heterozygous pathogenic variants and observed that they behaved like the control cells at rest or when stimulated with BMP9.<\/p>\n<\/sec>\n<sec><st>Conclusion<\/st>\n<p>We developed a SMAD4 functional assay that allows discrimination between benign and pathogenic <I>SMAD4<\/I> variants. We demonstrated that the underlying molecular mechanism of this pathogenicity is due mostly to a loss of hetero-oligomerisation. This assay will be transferable to clinical genetic laboratories and will improve the diagnosis of patients with HHT&ndash;JPS.<\/p>\n<\/sec>\n","protected":false},"excerpt":{"rendered":"<p>Background<br \/>\nHereditary haemorrhagic telangiectasia (HHT) and juvenile polyposis syndrome (JPS) can be caused by SMAD4 pathogenic variants. SMAD4 is a common transcription factor of the BMP\/TGF&beta; signalling pathway. In this study, we developed a cel&#8230;<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6,14,9],"tags":[83],"class_list":["post-1153","post","type-post","status-publish","format-standard","hentry","category-articulos","category-jmg","category-open-access","tag-jmedgenet"],"_links":{"self":[{"href":"https:\/\/sebigec.es\/blog\/index.php\/wp-json\/wp\/v2\/posts\/1153","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/sebigec.es\/blog\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/sebigec.es\/blog\/index.php\/wp-json\/wp\/v2\/types\/post"}],"replies":[{"embeddable":true,"href":"https:\/\/sebigec.es\/blog\/index.php\/wp-json\/wp\/v2\/comments?post=1153"}],"version-history":[{"count":1,"href":"https:\/\/sebigec.es\/blog\/index.php\/wp-json\/wp\/v2\/posts\/1153\/revisions"}],"predecessor-version":[{"id":1154,"href":"https:\/\/sebigec.es\/blog\/index.php\/wp-json\/wp\/v2\/posts\/1153\/revisions\/1154"}],"wp:attachment":[{"href":"https:\/\/sebigec.es\/blog\/index.php\/wp-json\/wp\/v2\/media?parent=1153"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/sebigec.es\/blog\/index.php\/wp-json\/wp\/v2\/categories?post=1153"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/sebigec.es\/blog\/index.php\/wp-json\/wp\/v2\/tags?post=1153"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}