Biology subjects

Borcuk, C.

Publications and source records attributed to Borcuk, C..

5 recordsLinked to original sources

bioRxiv2026

Liquidity of gene co-expression trajectories across the lifespan highlights delayed maturation and the perinatal GABA switch in schizophrenia risk

Schizophrenia genetic and environmental risk factors play out largely in early life, biasing development toward a pathogenic trajectory that becomes clinically apparent in early adulthood, when the disorder typically onsets. Here, we convert snapshots of gene expression in postmortem brain at a moment in time into a dynamic lifetime series employing the "liquidity" metric, a novel tool to track the evolution of networks across time from a multi-systemic perspective. The landscape of normal prefrontal cortical development becomes increasingly "liquid" during the first two decades of post-natal life, with sharp discontinuities in known critical periods such as birth and adolescence. Neurotypical individuals free of apparent neuropathology with relatively elevated polygenic risk scores for schizophrenia exhibit a generalized delay in the dynamics of liquidity across these trajectories compared to below-average-risk individuals. Impacted biological processes strongly converge on delayed GABA-A receptor functional maturation, involved in establishing Excitatory/Inhibitory balance in brain during early development. Similar to patients with schizophrenia, neurotypical high-risk individuals show an increased expression ratio between the genes SLC12A2 (protein NKCC1) and SLC12A5 (protein KCC2) relative to low-risk, involved in the control of the equilibrium potential of chloride ions that regulates GABA-A function. These results provide evidence that genetic risk for schizophrenia is associated with a delayed maturational profile and delayed maturation of GABAergic signaling without detectable neuropathology and well before the age of clinical onset. Interestingly, the same effect is not observed in the hippocampus and is not observed with genetic risk for other neuropsychiatric and immune conditions. The dynamics of maturation of GABA-A signaling in the dorsolateral prefrontal cortex emerge as an early contributor to translating genetic risk into an altered developmental trajectory associated with schizophrenia.

genomics↗

bioRxiv2026

Co-expression-based models improve eQTL predictions and highlightnovel transcriptome-wide genes associated with schizophrenia

Non-coding genetic variants statistically associated with complex heritability phenotypes are thought to act primarily through transcriptome regulatory mechanisms. Predictions of gene expression in tissue like the human brain traditionally rely primarily on cis-eQTLs. Here, we introduce INGENE and MODULE, trans-eQTLs models designed to enhance the prediction of gene expression by capturing the collective impact of candidate trans-eQTLs acting within co-expression networks. Exploiting RNA-seq data in six post-mortem brain regions (amygdala, caudate nucleus, dorsal/subgenual anterior cingulate cortex, dorsolateral prefrontal cortex, and hippocampus), we validate our models on two testing datasets, demonstrating increased gene predictability compared to both an original cis-based model and to EpiXcan, the leading benchmark in cis-model performance. Integration of cis- and trans-predictions significantly improves gene-level expression imputation (MLE = 0.05) for 18,744 genes across the six brain regions considered. Applying cis and trans models to PGC wave 3 genotypes identifies 766 SCZ-associated genes across brain regions (pFDR < .01), emphasizing the complementary nature of cis and trans predictions in trait association discovery. Of these genes, 641 represent novel transcriptome-wide associations with schizophrenia, highlighting the role of trans-heritability and genetic interactions underlying risk for this disorder, in addition to further supporting 125 previous candidates.

genomics↗

bioRxiv2024

Transcriptomics and proteomics of projection neurons in a circuit linking hippocampus with dorsolateral prefrontal cortex in human brain

Transcriptome and proteome sequencing of brain tissue homogenate has helped unravel processes underlying schizophrenia (SCZ). However, most studies have lacked granularity at the cell type level and have focused on individual brain regions, rather than examining expression dynamics across multiple regions or illness-relevant circuitries. We used laser capture microdissection to collect excitatory neuron-enriched samples from hippocampal subregions CA1 and presubiculum (SUB), and from dorsolateral prefrontal cortex (DLPFC), a circuit prominently implicated in schizophrenia. Using RNA sequencing and quantitative proteomics, we show significantly superior discrimination of brain regional identity in the transcriptomic (>90% accuracy) and proteomic data (>97% accuracy) compared with gene-level expression data (<70% in bulk). Patients with SCZ show hippocampal-specific differential protein phosphorylation. SCZ risk co-expression gene-sets that replicate across transcript and protein networks are enriched for transmembrane transporters in the DLPFC and CA1 and postsynaptic processes in the SUB. We demonstrate a strong directional connectivity effect of SCZ risk in that excitatory synaptic genes in CA1 unidirectionally predict gene expression in SUB. Finally, parallel CA1 snRNA-seq results suggest that in SCZ excitatory efferents in CA1 are affected by interactions with glia and by downregulation of inhibitory neuropeptide inputs. Our study proposes molecular mechanisms by which hippocampal communication, previously associated with SCZ at the macroscopic level, may be altered at the inter-field and interregional circuit level.

neuroscience↗

bioRxiv2022

Functional brain-wide network mapping during acute stress exposure in rats: Interaction between the lateral habenula and cortical, amygdalar, hypothalamic and monoaminergic regions.

Upon stress exposure a broad network of structures comes into play in order to provide adequate responses and restore homeostasis. It has been known for decades that the main structures engaged during the stress response are the medial prefrontal cortex, the amygdala, the hippocampus, the hypothalamus, the monoaminergic systems (noradrenaline, dopamine, serotonin), and the periaqueductal gray. The lateral habenula (LHb) is an epithalamic structure directly connected to prefrontal cortical areas and to the amygdala, whereas it functionally interacts with the hippocampus. Also, it is a main modulator of monoaminergic systems. The LHb is activated upon exposure to basically all types of stressors, suggesting it is also involved in the stress response. However, it remains unknown if and how the LHb functionally interacts with the broad stress response network. In the current study we performed in rats a restraint stress procedure followed by immunohistochemical staining of the c-Fos protein throughout the brain. Using Graph Theory-based functional connectivity analyses, we confirm the principal hubs of the stress network (e.g. prefrontal cortex, amygdala, periventricular hypothalamus), and show that the LHb is engaged during stress exposure in close interaction with the medial prefrontal cortex, the lateral septum, and the medial habenula. In addition, we performed DREADD-induced LHb inactivation during the same restraint paradigm in order to explore its consequences on the stress response network. This last experiment gave contrasting results as the DREADD ligand alone, clozapine-N-oxide, was able to modify the network. GRAPHICAL ABSTRACT GRAPHICAL ABSTRACT TEXTIn this study, using immunohistochemical staining of the immediate early gene c-fos and graph theory-based functional correlational analyses, we aimed at unravelling the possible engagement of the lateral habenula (LHb) within the stress response network during acute stress exposure (10-min restraint) in rats. We found that the medial part of the LHb (LHbM) was preferentially engaged, and that this engagement was concomitant to this of structures such as the medial prefrontal cortex (mPFC), the insular cortex (Ins), hypothalamic (PVH) and thalamic (PVT) paraventricular nuclei, the extended amygdala, comprising the Bed nucleus of the stria terminalis (BNST) and the entire amygdala (AMG), as well as the dopaminergic ventral tegmental area (VTA) and the serotonergic dorsal raphe nucleus (RD). This suggests upon stressful situations the LHbM serves as a relay of cortical, thalamic, hypothalamic and temporal information, further transmitted to midbrain monoaminergic systems to probably initiate coping strategies. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=134 SRC="FIGDIR/small/491280v1_ufig1.gif" ALT="Figure 1"> View larger version (29K): org.highwire.dtl.DTLVardef@a423eeorg.highwire.dtl.DTLVardef@32e1aaorg.highwire.dtl.DTLVardef@7d6106org.highwire.dtl.DTLVardef@16cff53_HPS_FORMAT_FIGEXP M_FIG C_FIG

animal behavior and cognition↗

bioRxiv2021

Early memory deficits and extensive brain network disorganization in the AppNL-F/MAPT double knock-in mouse model of familial Alzheimer's disease.

A critical challenge in current research on AD is to clarify the relationship between early neuropathology and network dysfunction associated to the emergence of subtle memory alterations which announce disease onset. In the present work, the new generation AppNL-F/MAPT double knock in (dKI) model was used to evaluate early stages of AD. The initial step of tau pathology was restricted to the perirhinal-entorhinal region, sparing the hippocampus. This discrete neuropathological sign was associated with deficits in the object-place associative memory, one of the earliest recognition memories affected in individuals at risk for developing AD. Analyses of task-dependent c-Fos activation was carried out in 22 brain regions across the medial prefrontal cortex, claustrum, retrosplenial cortex, and medial temporal lobe. Initial hyperactivity was detected in the entorhinal cortex and the claustrum of dKI mice. The retention phase was associated to reduced network efficiency especially across cingulate cortical regions, which may be caused by a disruption of information flow through the retrosplenial cortex. Moreover, the relationship between network global efficiency and memory performance in the WT could predict memory loss in the dKI, further linking reduced network efficiency to memory dysfunction. Our results suggest that early perirhinal-entorhinal pathology is associated with local hyperactivity which spreads towards connected regions such as the claustrum, the medial prefrontal cortex and ultimately the key retrosplenial hub which is needed to relay information flow from frontal to temporal lobes. The similarity between our findings and those reported in the earliest stages of AD suggests that the AppNL-F/MAPT dKI model has a high potential for generating key information on the initial stage of the disease.

neuroscience↗