Moreno, M. J. | bioRxiv Science

bioRxiv2025

Membrane partition and structural reorganization induced by anti-psychotics with distinct clinical profiles

Antipsychotics (APs) are used in the treatment of severe mental disorders. Their mechanism of action involves interaction with multiple brain targets, notably the dopamine D2 receptors (D2R), where they compete with dopamine. Due to their lipophilic nature, APs also partition and accumulate in lipid membranes, particularly around the D2R and in synaptic vesicles. When intercalated into brain membranes, APs slowly accumulate and act as a reservoir, allowing their rapid release on demand to modulate neurotransmitter signaling. They also modify the physicochemical and mechanical properties of the lipid bilayer. These modifications can subsequently affect the conformational changes of embedded membrane proteins like the D2R. The present study investigated two major APs with different pharmacological and clinical profiles: chlorpromazine, which exerts its clinical activity mainly through a strong antagonistic action at the D2R, and clozapine, the weakest D2R antagonist of all APs. Surprisingly, although D2R antagonism is usually associated with AP potency, clozapine has repeatedly demonstrated clinical superior efficacy to all APs and is therefore recommended for treatment-resistant schizophrenia. The current work aims to extend the classical AP receptor mediated paradigmatic mode of action to their potential and unique membrane remodeling properties by thoroughly comparing their partitioning and impact on the physicochemical properties of the lipid membrane. Lipid model membranes mimicking synaptic vesicles have been investigated using a combination of several biophysical methods. The study aims to determine how the partitioning of the two APs modifies membrane order, phase transition, thickness, elasticity, phase separation, membrane integrity and charge. Differences have been demonstrated between these two compounds, which may further differ both over time as they accumulate as well as depending on their pre- or post-synaptic location.

biophysics↗

bioRxiv2024

Loss of the lysosomal protein CLN3 modifies the lipid content of the nuclear envelope leading to DNA damage and activation of YAP1 pro-apoptotic signaling

Batten disease is characterized by early-onset blindness, juvenile dementia and death during the second decade of life. The most common genetic causes are mutations in the CLN3 gene encoding a lysosomal protein. There are currently no therapies targeting the progression of the disease, mostly due to the lack of knowledge about the disease mechanisms. To gain insight into the impact of CLN3 loss on cellular signaling and organelle function, we generated CLN3 knock-out cells in a human cell line (CLN3-KO), and performed RNA sequencing to obtain the cellular transcriptome. Following a multi-dimensional transcriptome analysis, we identified the transcriptional regulator YAP1 as a major driver of the transcriptional changes observed in CLN3-KO cells. We further observed that YAP1 pro-apoptotic signaling is hyperactive as a consequence of CLN3 functional loss in retinal pigment epithelia cells, and in the hippocampus and thalamus of CLN3ex{Delta}7/8 mice, an established model of Batten disease. Loss of CLN3 activates YAP1 by a cascade of events that starts with the inability of releasing glycerophosphodiesthers from CLN3-KO lysosomes, which leads to perturbations in the lipid content of the nuclear envelope and nuclear dysmorphism. This results in increased number of DNA lesions, activating the kinase c-Abl, which phosphorylates YAP1, stimulating its pro-apoptotic signaling. Altogether, our results highlight a novel organelle crosstalk paradigm in which lysosomal metabolites regulate nuclear envelope content, nuclear shape and DNA homeostasis. This novel molecular mechanism underlying the loss of CLN3 in mammalian cells and tissues may open new c-Abl-centric therapeutic strategies to target Batten disease.

cell biology↗