Identification of Hippocampus-Related and Sex-Specific Changes in AMOTL1 KO Mice – AMOTL1PD

Project implemented by:

Łukasiewicz Research Network – PORT Polish Center for Technology Development

The aim of the project is to determine the function of angiomotin-like protein 1 (AMOTL1) in the hippocampus, a brain structure responsible for consolidating short-term memory into long-term memory and thereby supporting learning and memory processes. The hippocampus is also involved in emotional regulation, motor activity control, and stress responses. In transgenic mice lacking AMOTL1 expression, we have observed a range of phenotypes characteristic of several neuropsychiatric disorders linked specifically to hippocampal dysfunction.

In this project, we will verify the hypothesis that AMOTL1 is indispensable for proper hippocampal function. To this end, we will generate genetically modified mice in which AMOTL1 is not produced in the hippocampus.

Motins are a family of proteins comprising three members: angiomotin (AMOT), angiomotin-like 1 (AMOTL1), and angiomotin-like 2 (AMOTL2). These proteins are involved in regulating gap junctions, cell adhesion, and cell migration. Some studies also implicate angiomotins in cancer development. Much less is known, however, about their functions in the central nervous system and in neuronal cells.

To date, four publications have reported roles of angiomotins in the brain. Wigerius et al. (doi: 10.1083/jcb.201705184) showed that AMOT is essential for the maturation of dendritic spines in hippocampal neurons in vitro. Cao et al. (https://doi.org/10.1038/s41419-023-06020-7) demonstrated that motin stability (regulated by ubiquitination) depends on WWC family proteins, and that deletion of WWC genes disrupts spinogenesis and impairs memory mechanisms in an AMOT-dependent manner. Zaltsman et al. (doi: 10.1016/j.stemcr.2019.03.009) showed that AMOT is crucial for neuronal differentiation from pluripotent stem cells in vitro.

The most recent study, by Rojek et al. (doi: 10.1371/journal.pbio.3000253), revealed that neuron-specific deletion of AMOT leads to cerebellar abnormalities at both the tissue and behavioral levels (gait and coordination impairments in mice). Our preliminary research shows that the remaining two angiomotin proteins—AMOTL1 and AMOTL2—are also expressed in hippocampal neurons. Moreover, preventing their expression specifically in neurons results (similar to AMOT deletion) in impaired development of dendritic spines.

However, unlike AMOT knockout mice, AMOTL1 knockout mice exhibit enlarged lateral ventricles and display hyperactivity, reduced anxiety, and diminished sociability. Many of the phenotypes we observed correspond to those found in certain neuropsychiatric disorders linked to hippocampal dysfunction.

The research problem addressed in this project concerns the function of AMOTL1 in the hippocampus. We hypothesize that AMOTL1 is essential for the proper functioning of this structure, which is involved in memory formation, emotional regulation, spatial navigation, motor control, and stress responses. To test this hypothesis, we will generate a mouse line that lacks AMOTL1 in the hippocampus. We will perform morphometric and histological analyses of brain tissue, assess the behavior of these mice, and conduct morphological analyses of neurons derived from them.

Additionally, we will investigate the mechanisms by which AMOTL1 regulates dendritic spine morphology and density, focusing on the expression and intracellular localization of proteins that may interact with AMOTL1. Our research will employ a wide range of experimental methods, including transgenic mouse models, comprehensive behavioral testing, fluorescence imaging of selected brain structures and cells, confocal microscopy, primary neuronal cultures, and purification of protein complexes from cells.