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Cararo-Lopes MM, Sadovnik R, Fu A, Suresh S, Gandu S, Firestein BL. Overexpression of α-Klotho isoforms promotes distinct Effects on BDNF-Induced Alterations in Dendritic Morphology. Mol Neurobiol 2024:10.1007/s12035-024-04171-y. [PMID: 38589756 DOI: 10.1007/s12035-024-04171-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 04/03/2024] [Indexed: 04/10/2024]
Abstract
α-Klotho (α-Kl) is a modulator of aging, neuroprotection, and cognition. Transcription of the Klotho gene produces two splice variants-a membrane protein (mKl), which can be cleaved and released into the extracellular milieu, and a truncated secreted form (sKl). Despite mounting evidence supporting a role for α-Kl in brain function, the specific roles of α-Kl isoforms in neuronal development remain elusive. Here, we examined α-Kl protein levels in rat brain and observed region-specific expression in the adult that differs between isoforms. In the developing hippocampus, levels of isoforms decrease after the third postnatal week, marking the end of the critical period for development. We overexpressed α-Kl isoforms in primary cultures of rat cortical neurons and evaluated effects on brain-derived neurotrophic factor (BDNF) signaling. Overexpression of either isoform attenuated BDNF-mediated signaling and reduced intracellular Ca2+ levels, with mKl promoting a greater effect. mKl or sKl overexpression in hippocampal neurons resulted in a partially overlapping reduction in secondary dendrite branching. Moreover, mKl overexpression increased primary dendrite number. BDNF treatment of neurons overexpressing sKl resulted in a dendrite branching phenotype similar to control neurons. In neurons overexpressing mKl, BDNF treatment restored branching of secondary and higher order dendrites close, but not distal, to the soma. Taken together, the data presented support the idea that sKl and mKl play distinct roles in neuronal development, and specifically, in dendrite morphogenesis.
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Affiliation(s)
- Marina Minto Cararo-Lopes
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
- Cell and Developmental Biology Graduate Program, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
| | - Ratchell Sadovnik
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
| | - Allen Fu
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
| | - Shradha Suresh
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
- Neuroscience Graduate Program, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
| | - Srinivasa Gandu
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
- Cell and Developmental Biology Graduate Program, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
| | - Bonnie L Firestein
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ, USA.
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