Biology subjects

Perni, M.

Publications and source records attributed to Perni, M..

6 recordsLinked to original sources

bioRxiv2026

Allele-specific rescue of neurexin behavioral phenotypes by monoamine-targeting compounds

Neurexins are synaptic adhesion molecules associated with neurologic changes in humans, including neurodevelopmental delay, autism, schizophrenia, Tourette syndrome, and seizures. The NRXN1 gene produces >100 protein isoforms through alternative promoters and extensive splicing, which are differentially impacted by NRXN1 variants found in patients. Yet pharmacologic targeting of NRXN1 isoforms or deletions has not been comprehensively studied. Here, we developed a behavioral screening approach in C. elegans to identify small molecule compounds that modify the decreased activity levels caused by isoform-specific deletions of neurexin(nrx-1). Screening 190 compounds, we discovered that monoamine-targeting compounds differentially improve behavioral phenotypes depending on which nrx-1 isoforms are disrupted. Broad modulation of monoamine signaling, or antagonism of specific serotonin receptors, are required to increase the activity of both alleles tested. The FDA-approved atypical antipsychotic olanzapine was the sole validated compound achieving Z-scores >2 in both screens, which notably also rescued behavioral phenotypes of C. elegans harboring a conserved autism-associated NRXN1 missense variant (L18Q/L16Q) identified in human patients. In Drosophila Nrx-1 mutants, olanzapine uniquely and significantly improved activity deficits and extended survival, demonstrating evolutionary conservation of our findings. Multi-behavior testing revealed pharmacological specificity: olanzapine improved both activity and social feeding phenotypes of nrx-1 alleles, while asenapine maleate improved activity, but worsened social feeding, indicating distinct impacts across behavioral domains. Our findings establish monoamine modulation as a conserved compensatory mechanism for neurexin loss, identify olanzapine as a lead compound for targeting neurexin loss, and demonstrate that allele stratification and pharmacogenomic approaches are needed for precision intervention in behavioral conditions. Neurexins are synaptic adhesion molecules implicated in autism, schizophrenia, and neurodevelopmental disorders. NRXN1 produces over 100 isoforms differentially affected by patient variants, yet pharmacologic targeting has not been systematically studied. We developed a C. elegans behavioral screen to identify compounds rescuing activity deficits caused by isoform-specific deletions. Screening 190 compounds, we discovered that monoamine-targeting drugs differentially improved behavioral phenotypes depending on which isoforms were disrupted. The FDA-approved antipsychotic olanzapine uniquely achieved robust rescue (Z-scores >2) across all genetic backgrounds tested, including a conserved autism-associated NRXN1 missense variant (L18Q/L16Q) identified in patients. Olanzapines efficacy was conserved in Drosophila Nrx-1 mutants, improving activity and extending survival. Multi-behavior testing revealed pharmacological specificity: olanzapine rescued both activity and social feeding phenotypes, while asenapine differentially affected behavioral domains. Our findings establish monoamine modulation as a compensatory mechanism for neurexin loss and identify olanzapine as a therapeutic lead for precision intervention in neurexin-associated disorders.

neuroscience↗

bioRxiv2026

Unique and overlapping behavioral effects of isoform-specific NRXN1 deletions across development

Mutations in the human neurexin 1 (NRXN1) gene are associated with neurodevelopmental disorders including autism and schizophrenia. Vertebrate NRXN1 produces three major NRXN1 isoforms, named , {beta}, and{gamma} . Human genetic data suggests that deletions located at the 5 region of the gene disrupting the isoform associate mostly with clinical behavioral deficits. Yet, 3 deletions that disrupt multiple isoforms have also been identified in clinical cases. Whether deletions that selectively affect specific NRXN1 isoforms result in specific behavioral deficits remains unclear. Here, we show that zebrafish harboring gene deletions that differentially encompass nrxn1a-, -{beta}, and/or -{gamma} display both unique and overlapping locomotion, sensorimotor behavior, and social behavior deficits. Combined, our results strongly support a model by which domain selective nrxn1 deletions predict behavioral phenotypes. Moreover, our results demonstrate compelling relationships between genotype and resulting behavioral phenotypes, providing functional insights into the complexity of NRXN1-associated neuropsychiatric behaviors.

neuroscience↗

bioRxiv2021

Vitamin A and vitamin E metabolites comodulate amyloid-β aggregation

Alzheimers disease is characterized by the presence in the brain of amyloid plaques formed by the aberrant deposition of the amyloid-{beta} peptide (A{beta}). Since many vitamins are dysregulated in this disease, we explored whether these molecules participate in protein homeostasis by modulating A{beta} aggregation. By screening 18 fat-soluble and water-soluble vitamins, we found that retinoic acid and -tocopherol, two metabolites of vitamin A and vitamin E, respectively, affect A{beta} aggregation both in vitro and in a C. elegans model of Alzheimers disease. We also show that effects of these two vitamin metabolites in combination can cancel each other out, suggesting that the complex composition of the cellular environment could have a protective role against protein aggregation through the simultaneous presence of aggregation promoters and inhibitors. Taken together, these results indicate that vitamins and their metabolites may be added to the list of components of the quality control system that regulate protein aggregation.

biophysics↗

bioRxiv2021

Cytosolic aggregation of mitochondrial proteins disrupts cellular homeostasis by stimulating other proteins aggregation

Mitochondria are organelles with their own genomes, but they rely on the import of nuclear-encoded proteins that are translated by cytosolic ribosomes. Therefore, it is important to understand whether failures in the mitochondrial uptake of these nuclear-encoded proteins can cause proteotoxic stress and identify response mechanisms that may counteract it. Here, we report that upon impairments in mitochondrial protein import, high-risk precursor and immature forms of mitochondrial proteins form aberrant deposits in the cytosol. These deposits then cause further cytosolic accumulation and consequently aggregation of other mitochondrial proteins and disease-related proteins, including -synuclein and amyloid {beta}. This aggregation triggers a cytosolic protein homeostasis imbalance that is accompanied by specific molecular chaperone responses at both the transcriptomic and protein levels. Altogether, our results provide evidence that mitochondrial dysfunction, specifically protein import defects, contributes to impairments in protein homeostasis, thus revealing a possible molecular mechanism by which mitochondria are involved in neurodegenerative diseases.

molecular biology↗

bioRxiv2019

Small molecule sequestration of amyloid-β as a drug discovery strategy for Alzheimer’s disease

Disordered proteins are challenging therapeutic targets, and no drug is currently in clinical use that has been shown to modify the properties of their monomeric states. Here, we identify a small molecule capable of binding and sequestering the amyloid-{beta} peptide (A{beta}) in its monomeric, soluble state. Our analysis reveals that this compound interacts with A{beta} and inhibits both the primary and secondary nucleation pathways in its aggregation process. We characterise this interaction using biophysical experiments and integrative structural ensemble determination methods. We thus observe that this small molecule has the remarkable effect of increasing the conformational entropy of monomeric A{beta} while decreasing its hydrophobic surface area. We then show that this small molecule rescues a Caenorhabditis elegans model of A{beta}-associated toxicity in a manner consistent with the mechanism of action identified from the in silico and in vitro studies. These results provide an illustration of the strategy of targeting the monomeric states of disordered proteins with small molecules to alter their behaviour for therapeutic purposes.

biophysics↗

bioRxiv2018

Fast fluorescence lifetime imaging reveals the maturation process of α-synuclein aggregates in ageing Caenorhabditis elegans

The nematode worm Caenorhabditis elegans has emerged as an important model organism to study the molecular mechanisms of protein misfolding diseases associated with amyloid formation because of its small size, ease of genetic manipulation and optical transparency. Obtaining a reliable and quantitative read-out of protein aggregation in this system, however, remains a challenge. To address this problem, we here present a fast time-gated fluorescence lifetime imaging (TG-FLIM) method and show that it provides functional insights into the process of protein aggregation in living animals by enabling the rapid characterisation of different types of aggregates. More specifically, in longitudinal studies of C. elegans models of Parkinsons and Huntingtons diseases, we observed marked differences in the aggregation kinetics and the nature of the protein inclusions formed by -synuclein and polyglutamine. In particular, we found that -synuclein inclusions do not display amyloid-like features until late in the life of the worms, whereas polyglutamine forms amyloid characteristics rapidly in early adulthood. Furthermore, we show that the TG-FLIM method is capable of imaging live and non-anaesthetised worms moving in specially designed agarose micro-chambers. Taken together, our results show that the TG-FLIM method enables high-throughput functional imaging of living C. elegans that can be used to study in vivo mechanisms of aggregation and that has the potential to aid the search for therapeutic modifiers of protein aggregation and toxicity.

biophysics↗