Biology subjects

Gozes, I.

Publications and source records attributed to Gozes, I..

6 recordsLinked to original sources

bioRxiv2026

The Female Side of Autism: Sexual Dichotomies impacting the Helsmoortel-Van der Aa syndrome pathology.

Background: Helsmoortel-Van der Aa syndrome, caused by pathogenic variants in ADNP, is characterised by substantial clinical heterogeneity, but how biological sex influences disease biology and treatment response remains an emerging area of investigation. Here, we investigated whether sex modifies the behavioural and molecular consequences of Adnp deficiency, the response to the investigational drug candidate davunetide (NAP), and the clinical phenotype of Helsmoortel-Van der Aa syndrome. Methods: We studied male and female Adnp heterozygous mice harbouring the p.Leu822Hisfs*6 variant and sex-matched wild-type littermates using continuous 24-h behavioural phenotyping, hippocampal genome-wide DNA methylation and bulk RNA sequencing. NAP effects on behaviour, hippocampal ADNP protein abundance, and epi-transcriptomic responses were assessed using genotype-by-treatment models. Four Core Genotypes mice were assessed to distinguish sex-chromosome and gonadal contributions to hippocampal Adnp transcript expression, and reproductive-tissue transcriptomes were analysed in Adnp mice to unravel a possible endocrine component of the disease. Findings were compared with clinical and developmental data from 129 individuals with Helsmoortel-Van der Aa syndrome. Findings: Adnp deficiency produced a shared overall behavioural phenotype in male and female mice, but through distinct patterns of behavioural disruption, indicating that sex modifies the implementation rather than the magnitude of the phenotype. This distinction was also evident at the molecular level: hippocampal DNA methylation was predominantly determined by genotype and showed convergence between sexes, whereas transcriptional responses diverged, with mitochondrial pathways predominating in males and chromatin, RNA processing, and cell-cycle pathways in females. NAP partially shifted behavioural abnormalities towards the wild-type state in both sexes and increased hippocampal ADNP protein abundance in heterozygous mice, without reversing the underlying methylation phenotype. Its transcriptional effects were markedly broader in males, indicating a sex-dependent molecular response to treatment. In reproductive tissues, Adnp deficiency was associated with convergent alterations in steroid hormone biosynthesis, despite no evidence for direct regulation of hippocampal Adnp expression by sex-chromosome complement or gonadal hormonal state. By contrast, sex was not associated with robust differences across the clinical and developmental features assessed in 129 individuals with Helsmoortel-Van der Aa syndrome after correction for multiple testing. Interpretation: Biological sex modifies how Adnp deficiency is expressed at behavioural and molecular levels, but these differences do not necessarily define distinct clinical phenotypes. The convergence of the methylation response alongside greater divergence in transcriptional and behavioural responses identifies sex as a modifier of disease biology rather than a determinant of the core phenotype. The sex-dependent response to NAP further indicates that biological sex may influence pharmacological responses even when treatment-associated behavioural improvement is observed in both sexes. These findings support consideration of biological sex as a prespecified variable in preclinical and clinical studies of Helsmoortel-Van der Aa syndrome and suggest that systematic investigation of sex-dependent biology may also be relevant to therapeutic development across rare diseases. Keywords: Helsmoortel-Van der Aa syndrome (HVDAS), Activity-Dependent Neuroprotective Protein (ADNP), autism spectrum disorder, intellectual disability, sex, mouse model, behaviour.

genetics↗

bioRxiv2026

Novel estrogen replacement combination therapy including the investigational drug davunetide

Estrogen is an essential hormone that critically impacts bodily and brain functions, supporting learning, memory, and motor activities. A decrease in estrogen levels is associated with cognitive decline and motor dysfunction, such as muscle weakness. While conventional hormone replacement treatments (HRT) exist, those have limitations and potentially severe side effects. NAP (davunetide) is the smallest neuroprotective peptide site of activity-dependent neuroprotective protein (ADNP), a master regulator of cognition, essential for brain formation. It is known that NAP restores ADNP activity in cases of deficiency and it has already shown potential in preventing cognitive impairment, protecting against tauopathy, and improving motor function in various animal models and in clinical trials. Based on the dynamic regulation of ADNP by the estrous cycle and its involvement in steroidogenic pathways, we hypothesize that NAP may restore ADNP activity and thus serve as an alternative to conventional hormonal treatments. To test this, 3-month-old female ICR mice underwent bilateral ovariectomy (OVX) or Sham surgery and received daily intranasal administration of NAP, estrogen, or vehicle. Results showed a significant reduction in weight-normalized forelimb grip strength in the OVX model. Daily administration of NAP or estrogen resulted in intermediate grip strength levels that did not statistically differ from either the Sham control or untreated OVX groups. Interestingly, grip strength was the only test that yielded significant results, and no significant differences were observed in the Novel Object Recognition (NOR) test or computed tomography (CT) scans. These findings suggest that NAP may effectively prevent the loss of physical force production typically seen following ovarian hormone depletion, presenting a viable, non-hormonal candidate strategy for managing musculoskeletal symptoms. We hypothesize that the lack of significance in other parameters was due to soy-derived phytoestrogens in the diet, which may have exerted a systemic estrogenic effect that masked the expected physiological phenotypes typically observed in OVX models. Future replication using phytoestrogen-deficient food is required to isolate the specific neuroprotective and musculoskeletal effects of NAP from dietary influence and clarify the broader therapeutic benefits of NAP.

neuroscience↗

bioRxiv2024

Oxidative stress promotes axonal atrophy through alterations in microtubules and EB1 function

Axons are crucial for transmitting neurochemical signals. As organisms age, the ability of neurons to maintain their axons declines; hence aged axons are more susceptible to damage or dysfunction. Understanding what causes axonal vulnerability is crucial for developing strategies to enhance overall resilience of neurons, and to prevent their deterioration during ageing or in age-related neurodegenerative diseases. Increasing levels of reactive oxygen species (ROS) causes oxidative stress, a hallmark of ageing and age-related diseases. Despite this association, a causal relationship between oxidative stress and neuronal ageing remains unclear, particularly how subcellular physiology is affected by ROS. By using Drosophila-derived primary neuronal cultures and a recently developed in vivo neuronal model of ageing, which involves the visualisation of Drosophila medulla neurons, we investigated the interplay between oxidative stress, neuronal ageing and the microtubule cytoskeleton. We find that oxidative stress as a key driver of axonal and synaptic decay, including the appearance of axonal swellings, microtubule alterations in both axons and synapses and the morphological transformation of axonal terminals during ageing. We demonstrate that increased ROS sensitises the microtubule plus end binding factor, end-binding protein 1 (EB1), leading to microtubule defects, affecting neuronal integrity. Furthermore, manipulating EB1 proved to be a valuable therapeutic strategy to prevent ageing hallmarks observed in conditions of elevated ROS. In summary, we demonstrate a mechanistic pathway linking cellular oxidative stress, the microtubule cytoskeleton and axonal deterioration during ageing and provide evidence of the therapeutic potential of enhancing microtubule plus end physiology to improve the resilience of axons.

neuroscience↗

bioRxiv2022

De Novo, Post-Zygotic, Inter-Tissue Mosaicism of Cell Autonomous ADNP Mutations in Autistic Individuals: Restricted Environmental Contribution

Many neurodevelopmental disorders, including autism, are caused by de novo mutations, that might arise as early as in the parental germline, during embryonic, fetal development, or as late as post-natal aging. Intra-tissue mutation-load variations could impact clinical presentation. One of the most common causes of autism is de novo mutations in ADNP. We developed an ultra-sensitive, highly-quantitative droplet digital PCR assay to determine ADNP mutation levels in patient tissues, including blood, teeth, hair, and 24 different tissues from a post-mortem de novo ADNP-mutated child ([~]6-years old), including a transplanted liver from a non-mutant donor (retained for 22 months). Striking variations of ADNP mosaicism arose between tissues of the same individual. Mutation load differences were evident between post-mortem tissues, but not in the transplanted liver -- supporting a cell autonomous genetic vulnerability to de novo mutations, arguing against a transferable environmentally-sensitive DNA damage/mutation predisposition. Variations between tissues suggest a developmental timing of the mutations. Most individuals showed at least one tissue with less than heterozygous mutations, where the presence of the homozygous non-mutant cells indicates that de novo ADNP mutations arose post-zygotically. Highly variable ADNP mosaicism between tissues, that within an individual can be less than heterozygous or approach homozygosity, indicate rapid ongoing post-zygotic, and possibly post-natal, somatic mutations, contributing to clinical variability.

genetics↗

bioRxiv2021

Improving replicability using interaction with laboratories: a multi-lab experimental assessment

Experimentation with mouse and rat models has become a central strategy for discovering mammalian gene function, and for preclinical testing of pharmacological treatments, yet the utility of any findings critically depends on their replicability in other laboratories. In previous publications we proposed a statistical approach for estimating the inter-laboratory replicability of novel discoveries made in a single laboratory. We demonstrated that previous phenotyping results from multi-lab databases can be used to derive a Genotype-by-Lab (GxL) adjustment factor to greatly enhance the replicability of the single-lab findings, for similarly measured phenotypes, even before making the effort of replicating these finding in additional laboratories. This demonstration, however, still raised several important questions that could only be answered by an additional large-scale prospective experiment: 1) Does GxL-adjustment work in single-lab experiments that were not intended to be standardized across laboratories, and with genotypes that were not included in the previous experiments? And 2) Can it be used to adjust the results of pharmacological experiments? We investigated these questions by attempting to replicate, across three laboratories, results from five single-lab studies in the Mouse Phenome Database (MPD), offering 212 comparisons, including 60 involving a pharmacological treatment: 18 mg/kg/day fluoxetine. In addition, we define and use a dimensionless GxL factor, by dividing the GxL variance by the standard deviation between animals within groups, as a more robust vehicle to transfer the adjustment from the multi-lab analysis to very different labs and genotypes. For genotype comparisons, GxL-adjustment reduced the rate of non-replicable discoveries from 60% to 12%, for the price of reducing the power to make replicable discoveries from 87% to 66%. In absolute numbers, the adjustment prevented 23 non-replicable discoveries for the price of missing only three replicated ones. Tools and data needed for deployment of this method across other mouse experiments are publicly available in MPD. Our results further point at some phenotypes as more prone to produce non-replicable results, while others, known to be more difficult to measure, are as likely to produce replicable results (once adjusted) such as the physiological measure, body weight.

animal behavior and cognition↗

bioRxiv2018

NAP (davunetide) preferential interaction with dynamic 3-repeat Tau explains differential protection in selected tauopathies

The microtubule (MT) associated protein Tau is instrumental for the regulation of MT assembly and dynamic instability, orchestrating MT-dependent cellular processes. Aberration in Tau post-translational modifications ratio deviation of spliced Tau isoforms 3 or 4 MT binding repeats (3R/4R) have been implicated in neurodegenerative tauopathies. Activity-dependent neuroprotective protein (ADNP) is vital for brain formation and cognitive function. ADNP deficiency in mice causes pathological Tau hyperphosphorylation and aggregation, correlated with impaired cognitive functions. It has been previously shown that the ADNP-derived peptide NAP protects against ADNP deficiency, exhibiting neuroprotection, MT interaction and memory protection. NAP prevents MT degradation by recruitment of Tau and end-binding proteins to MTs and expression of these proteins is required for NAP activity. Clinically, NAP (davunetide, CP201) exhibited efficacy in prodromal Alzheimers disease patients (Tau3R/4R tauopathy) but not in progressive supranuclear palsy (increased Tau4R tauopathy). Here, we examined the potential preferential interaction of NAP with 3R vs. 4R Tau, toward personalized treatment of tauopathies. Affinity-chromatography showed that NAP preferentially interacted with Tau3R protein from rat brain extracts and fluorescence recovery after photobleaching assay indicated that NAP induced increased recruitment of human Tau3R to MTs under zinc intoxication, in comparison to Tau4R. Furthermore, we showed that NAP interaction with tubulin (MTs) was inhibited by obstruction of Tau-binding sites on MTs, confirming the requirement of Tau-MT interaction for NAP activity. The preferential interaction of NAP with Tau3R may explain clinical efficacy in mixed vs. Tau4R pathologies, and suggest effectiveness in Tau3R neurodevelopmental disorders.

neuroscience↗