Raj Nayan Sewduth1,2, Silvia Pandolfi1,2, Mikhail Steklov1,2, Aidana Sheryazdanova1,2, Peihua Zhao1,2, Nathan Criem1,2, Maria F Baietti1,2, Benoit Lechat1,2, Rozeen Quarck3, Francis Impens4,5,6, Anna A Sablina1,2. 1. From the VIB-KU Leuven Center for Cancer Biology, Belgium (R.N.S., S.P., M.S., A.S., P.Z., N.C., M.F.B., B.L., A.A.S.). 2. Department of Oncology, KU Leuven, Belgium (R.N.S., S.P., M.S., A.S., P.Z., N.C., M.F.B., B.L., A.A.S.). 3. University Hospitals and Department of Chronic Diseases, Metabolism & Ageing (CHROMETA), KU Leuven, Belgium (R.Q.). 4. Department of Biomolecular Medicine, Ghent University, Belgium (F.I.). 5. VIB Center for Medical Biotechnology, Belgium (F.I.). 6. VIB Proteomics Core, Albert Baertsoenkaai 3, Belgium (F.I.).
Abstract
RATIONALE: Noonan syndrome (NS) is one of the most frequent genetic disorders. Bleeding problems are among the most common, yet poorly defined complications associated with NS. A lack of consensus on the management of bleeding complications in patients with NS indicates an urgent need for new therapeutic approaches. OBJECTIVE: Bleeding disorders have recently been described in patients with NS harboring mutations of LZTR1 (leucine zipper-like transcription regulator 1), an adaptor for CUL3 (CULLIN3) ubiquitin ligase complex. Here, we assessed the pathobiology of LZTR1-mediated bleeding disorders. METHODS AND RESULTS: Whole-body and vascular specific knockout of Lztr1 results in perinatal lethality due to cardiovascular dysfunction. Lztr1 deletion in blood vessels of adult mice leads to abnormal vascular leakage. We found that defective adherent and tight junctions in Lztr1-depleted endothelial cells are caused by dysregulation of vesicular trafficking. LZTR1 affects the dynamics of fusion and fission of recycling endosomes by controlling ubiquitination of the ESCRT-III (endosomal sorting complex required for transport III) component CHMP1B (charged multivesicular protein 1B), whereas NS-associated LZTR1 mutations diminish CHMP1B ubiquitination. LZTR1-mediated dysregulation of CHMP1B ubiquitination triggers endosomal accumulation and subsequent activation of VEGFR2 (vascular endothelial growth factor receptor 2) and decreases blood levels of soluble VEGFR2 in Lztr1 haploinsufficient mice. Inhibition of VEGFR2 activity by cediranib rescues vascular abnormalities observed in Lztr1 knockout mice Conclusions: Lztr1 deletion phenotypically overlaps with bleeding diathesis observed in patients with NS. ELISA screening of soluble VEGFR2 in the blood of LZTR1-mutated patients with NS may predict both the severity of NS phenotypes and potential responders to anti-VEGF therapy. VEGFR inhibitors could be beneficial for the treatment of bleeding disorders in patients with NS.
RATIONALE: Noonan syndrome (NS) is one of the most frequent genetic disorders. Bleeding problems are among the most common, yet poorly defined complications associated with NS. A lack of consensus on the management of bleeding complications in patients with NS indicates an urgent need for new therapeutic approaches. OBJECTIVE:Bleeding disorders have recently been described in patients with NS harboring mutations of LZTR1 (leucine zipper-like transcription regulator 1), an adaptor for CUL3 (CULLIN3) ubiquitin ligase complex. Here, we assessed the pathobiology of LZTR1-mediated bleeding disorders. METHODS AND RESULTS: Whole-body and vascular specific knockout of Lztr1 results in perinatal lethality due to cardiovascular dysfunction. Lztr1 deletion in blood vessels of adult mice leads to abnormal vascular leakage. We found that defective adherent and tight junctions in Lztr1-depleted endothelial cells are caused by dysregulation of vesicular trafficking. LZTR1 affects the dynamics of fusion and fission of recycling endosomes by controlling ubiquitination of the ESCRT-III (endosomal sorting complex required for transport III) component CHMP1B (charged multivesicular protein 1B), whereas NS-associated LZTR1 mutations diminish CHMP1B ubiquitination. LZTR1-mediated dysregulation of CHMP1B ubiquitination triggers endosomal accumulation and subsequent activation of VEGFR2 (vascular endothelial growth factor receptor 2) and decreases blood levels of soluble VEGFR2 in Lztr1haploinsufficientmice. Inhibition of VEGFR2 activity by cediranib rescues vascular abnormalities observed in Lztr1 knockout mice Conclusions: Lztr1 deletion phenotypically overlaps with bleeding diathesis observed in patients with NS. ELISA screening of soluble VEGFR2 in the blood of LZTR1-mutated patients with NS may predict both the severity of NS phenotypes and potential responders to anti-VEGF therapy. VEGFR inhibitors could be beneficial for the treatment of bleeding disorders in patients with NS.
Authors: Verica Vasic; Mattson S O Jones; Denise Haslinger; Lisa S Knaus; Michael J Schmeisser; Gaia Novarino; Andreas G Chiocchetti Journal: Genes (Basel) Date: 2021-10-30 Impact factor: 4.141
Authors: Antonio Cuevas-Navarro; Laura Rodriguez-Muñoz; Joaquim Grego-Bessa; Alice Cheng; Katherine A Rauen; Anatoly Urisman; Frank McCormick; Gerardo Jimenez; Pau Castel Journal: Elife Date: 2022-04-25 Impact factor: 8.713