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Mecklenburg N, Kowalczyk I, Witte F, Görne J, Laier A, Mamo TM, Gonschior H, Lehmann M, Richter M, Sporbert A, Purfürst B, Hübner N, Hammes A. Identification of disease-relevant modulators of the SHH pathway in the developing brain. Development 2021; 148:272000. [PMID: 34463328 DOI: 10.1242/dev.199307] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 07/19/2021] [Indexed: 12/13/2022]
Abstract
Pathogenic gene variants in humans that affect the sonic hedgehog (SHH) pathway lead to severe brain malformations with variable penetrance due to unknown modifier genes. To identify such modifiers, we established novel congenic mouse models. LRP2-deficient C57BL/6N mice suffer from heart outflow tract defects and holoprosencephaly caused by impaired SHH activity. These defects are fully rescued on a FVB/N background, indicating a strong influence of modifier genes. Applying comparative transcriptomics, we identified Pttg1 and Ulk4 as candidate modifiers upregulated in the rescue strain. Functional analyses showed that ULK4 and PTTG1, both microtubule-associated proteins, are positive regulators of SHH signaling, rendering the pathway more resilient to disturbances. In addition, we characterized ULK4 and PTTG1 as previously unidentified components of primary cilia in the neuroepithelium. The identification of genes that powerfully modulate the penetrance of genetic disturbances affecting the brain and heart is likely relevant to understanding the variability in human congenital disorders.
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Affiliation(s)
- Nora Mecklenburg
- Disorders of the Nervous System, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
| | - Izabela Kowalczyk
- Disorders of the Nervous System, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
| | - Franziska Witte
- Cardiovascular and Metabolic Sciences, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
| | - Jessica Görne
- Disorders of the Nervous System, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
| | - Alena Laier
- Disorders of the Nervous System, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
| | - Tamrat M Mamo
- Disorders of the Nervous System, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
| | - Hannes Gonschior
- Cellular Imaging, Light Microscopy, Leibniz-Research Institute for Molecular Pharmacology (FMP), 13125 Berlin, Germany
| | - Martin Lehmann
- Cellular Imaging, Light Microscopy, Leibniz-Research Institute for Molecular Pharmacology (FMP), 13125 Berlin, Germany
| | - Matthias Richter
- Advanced Light Microscopy Technology Platform, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
| | - Anje Sporbert
- Advanced Light Microscopy Technology Platform, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
| | - Bettina Purfürst
- Electron microscopy technology platform, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
| | - Norbert Hübner
- Cardiovascular and Metabolic Sciences, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Berlin, 10785 Berlin, Germany.,Charité-Universitätsmedizin Berlin, 10117 Berlin, Germany.,Berlin Institute of Health (BIH), 10178 Berlin, Germany
| | - Annette Hammes
- Disorders of the Nervous System, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
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