ABSTRACT
The collapsin response mediator protein (CRMP) family proteins are intracellular mediators of neurotrophic factors regulating neurite structure/spine formation and are essential for dendrite patterning and directional axonal pathfinding during brain developmental processes. Among this family, CRMP5/DPYSL5 plays a significant role in neuronal migration, axonal guidance, dendrite outgrowth, and synapse formation by interacting with microtubules. Here, we report the identification of missense mutations in DPYSL5 in nine individuals with brain malformations, including corpus callosum agenesis and/or posterior fossa abnormalities, associated with variable degrees of intellectual disability. A recurrent de novo p.Glu41Lys variant was found in eight unrelated patients, and a p.Gly47Arg variant was identified in one individual from the first family reported with Ritscher-Schinzel syndrome. Functional analyses of the two missense mutations revealed impaired dendritic outgrowth processes in young developing hippocampal primary neuronal cultures. We further demonstrated that these mutations, both located in the same loop on the surface of DPYSL5 monomers and oligomers, reduced the interaction of DPYSL5 with neuronal cytoskeleton-associated proteins MAP2 and ßIII-tubulin. Our findings collectively indicate that the p.Glu41Lys and p.Gly47Arg variants impair DPYSL5 function on dendritic outgrowth regulation by preventing the formation of the ternary complex with MAP2 and ßIII-tubulin, ultimately leading to abnormal brain development. This study adds DPYSL5 to the list of genes implicated in brain malformation and in neurodevelopmental disorders.
Subject(s)
Agenesis of Corpus Callosum/genetics , Cerebellum/abnormalities , Mutation, Missense/genetics , Neurodevelopmental Disorders/genetics , Adult , Agenesis of Corpus Callosum/diagnostic imaging , Cerebellum/diagnostic imaging , Child , Child, Preschool , Female , Humans , Hydrolases/chemistry , Hydrolases/genetics , Intellectual Disability/diagnostic imaging , Intellectual Disability/genetics , Male , Microtubule-Associated Proteins/chemistry , Microtubule-Associated Proteins/genetics , Microtubule-Associated Proteins/metabolism , Models, Molecular , Neurodevelopmental Disorders/diagnostic imaging , Tubulin/metabolism , Young AdultABSTRACT
Spinal cord injury (SCI) is a severe disable symptom and has posed a great health threat to many people. Circ-HIPK3 has been reported to modulate the biological behavior of neuronal cells. Thence, in this study, we explored the mechanism of circ-HIPK3 in affecting functions of neuronal cell in SCI. SCI rat model was constructed to evaluate the apoptosis condition of spinal cord tissue. Meanwhile, 100⯵M of CoCl2 was used to treat AGE1.HN and PC12â¯cells to induce in vitro SCI model. Functional assays were implemented to investigate the apoptosis of AGE1.HN and PC12â¯cells. RNase R and Act D treatment were both conducted to verify the circular character of circ-HIPK3. In this study, circ-HIPK3 was found lowly expressed in SCI rat models and AGE1.HN and PC12â¯cells induced by 100uM of CoCl2. Meanwhile, inhibited circ-HIPK3 or overexpressed circ-HIPK3 could separately elevate or reduce the apoptosis of AGE1.HN and PC12â¯cells. Moreover, circ-HIPK3 was identified as the ceRNA against miR-558 to up-regulate DPYSL5. Circ-HIPK3/miR-558/DPYSL5 axis modulated the apoptosis of AGE1.HN and PC12â¯cells in SCI. In conclusion, circ-HIPK3 relieves the neuronal cell apoptosis through regulating miR-588/DPYSL5 axis in SCI.