Biology subjects

Kandel, E. R.

Publications and source records attributed to Kandel, E. R..

6 recordsLinked to original sources

bioRxiv2025

CircRNA hypomethylation in the human amygdala implicates FKBP5 in alcohol use disorder

Genome- and phenome-wide association studies implicate the RNA demethylase FTO in alcohol use disorder (AUD), yet the RNA methylation landscape in AUD remains poorly characterized. Analyzing postmortem human basolateral amygdala (BLA) tissue, a key brain region in AUD-related behaviors, we found extensive m6A hypomethylation uniquely affecting circular RNAs (circRNAs). Notably, FKBP5-hosted circRNAs (circFKBP5s) exhibited pronounced hypomethylation correlating with elevated expression of FKBP5 mRNA isoforms. These findings were replicated in an animal model of alcohol dependence. Predictive analyses suggest that circFKBP5s influence genes involved in neurodevelopmental processes and neuronal identity. These findings uncover a novel aspect of AUD neurobiology linked to circRNA methylation.

molecular biology↗

bioRxiv2022

SUMO2 Protects Against Tau-induced Synaptic and Cognitive Dysfunction

Abnormal intracellular accumulation of Tau aggregates is a hallmark of Alzheimers disease (AD) and other Tauopathies, such as Frontotemporal dementia (FTD), which can be caused by mutations of Tau. Mutated and pathological Tau can undergo a range of post-translational modifications (PTMs) that might trigger or modulate disease pathology. Recent studies indicate that modification of wild type Tau by Small ubiquitin-like modifier SUMO isoform 1 (SUMO1) controls Tau hyperphosphorylation and aggregation, suggesting that SUMOylation acts as a central regulator of Taus biochemical properties. Besides SUMO1, Tau is modified by SUMO2/3, however the consequences of this modification have not been investigated. Here, using viral approaches on primary hippocampal neurons, transgenic mice expressing mutant Tau and SUMO2, and iPSC-derived neurons from FTD patients, we evaluated whether SUMO2/3 conjugation modifies the neurodegenerative disease pathology associated with the aggregation-prone mutant Tau P301L, P301S, and R406W variants. We found that mutant forms of Tau are targets of SUMO2/3, and SUMO2/3 conjugation is neuroprotective. Importantly, expression of mutant Tau is accompanied by a significant reduction of SUMO2/3 conjugation levels, and restoring levels of SUMO2 reduces mutant Tau aggregation and phosphorylation in all model systems Furthermore, overexpression of SUMO2 restores levels of pre- and post-synaptic markers, associated with a complete rescue of the LTP and memory deficits in transgenic mice expressing mutant Tau. These findings bring to light the potential therapeutic implication of manipulating SUMO conjugation to detoxify Tau through PTM-based approaches.

neuroscience↗

bioRxiv2021

A direct lateral entorhinal cortex to hippocampal CA2 circuit conveys social information required for social memory

The storage of information by the hippocampus in long-term memory is thought to involve two distinct but related processes. First, the hippocampus determines whether a given stimulus is novel or familiar; next, the hippocampus stores the novel information in long-term memory. To date, the neural circuits that detect novelty and their relation to the circuits that store information of a specific memory are poorly understood. Here we address this question by examining the circuits by which the CA2 region of the hippocampus, which is essential for social memory, both detects social novelty and stores social memory. CA2, like the more thoroughly studied CA1 region, receives its major excitatory input from the entorhinal cortex through both a direct monosynaptic and indirect trisynaptic pathway. We find that the direct inputs to CA2 from the lateral entorhinal cortex, but not the indirect trisynaptic inputs, provide social information that is required for social memory. However, these direct inputs fail to discriminate a novel from a familiar animal. Thus, social novelty and social identity signals are likely conveyed through separate pathways, with the entorhinal cortex providing specific multisensory information about an animals identity and novelty detection requiring a local computation within CA2.

neuroscience↗

bioRxiv2021

The gastrin-releasing peptide regulates stress-enhanced fear and dopamine signaling

Fear extinction is an adaptive behavioral process critical for organisms survival, but deficiency in extinction may lead to PTSD. While the amygdala and its neural circuits are critical for fear extinction, the molecular identity and organizational logic of cell types that lie at the core of these circuits remain unclear. Here we report that mice deficient for amygdala-enriched gastrin-releasing peptide gene (Grp-/-) exhibit enhanced neuronal activity in the basolateral amygdala (BLA) and stronger fear conditioning, as well as deficient extinction in stress-enhanced fear learning (SEFL). rAAV2-retro-based tracing combined with visualization of the GFP knocked in the Grp gene showed that BLA receives GRPergic or conditioned stimulus projections from the indirect auditory thalamus-to-auditory cortex pathway, ventral hippocampus and ventral tegmental area. Transcription of dopamine-related genes was decreased in BLA of Grp-/- mice following SEFL extinction recall, suggesting that the GRP may mediate fear extinction regulation by dopamine. Impact statementMice deficient for the amygdala-enriched gastrin-releasing peptide gene are susceptible to stress-enhanced fear, a behavioral protocol with relevance to PTSD, and show a decrease in dopamine-related gene transcription.

neuroscience↗

bioRxiv2018

Deep brain stimulation of the nucleus accumbens shell does not decrease cocaine self-administration in cocaine-dependent rats but increases GluR1/GluA1 in the central nucleus of the amygdala

BackgroundCocaine addiction is a major public health problem. Despite decades of intense research, no effective treatments are available. Both preclinical and clinical studies of drug addiction strongly suggest that the nucleus accumbens (NAcc) is a viable target for deep brain stimulation (DBS).\n\nObjectiveAlthough previous studies have shown that DBS of the NAcc decreases cocaine seeking and reinstatement, the effects of DBS on cocaine intake in cocaine-dependent animals have not yet been investigated.\n\nMethodsRats were made cocaine-dependent by allowing them to self-administer cocaine in long-access sessions (6 h, 0.5 mg/kg/infusion). The effects of high-frequency DBS of the NAcc shell on cocaine intake was then studied. Furthermore, cocaine-induced locomotor activity, irritability-like behavior during cocaine abstinence and the levels of the -amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunits 1 and 2 (GluR1/GluA1 and GluR2/GluA2) after DBS were investigated.\n\nResultsContrary to our expectations, DBS of the NAcc shell induced a slight increase in both cocaine self-administration and cocaine-induced locomotor activity. In addition, 18 h into cocaine withdrawal, we found that DBS decreased irritability-like behavior. We also found that DBS-induced a robust increase in both cytosolic and synaptosomal levels of GluR1, but not GluR2, specifically in the central nucleus of the amygdala but not in other brain regions.\n\nConclusionsThese preclinical results with cocaine-dependent animals do not support high-frequency DBS of the NAcc shell as a therapeutic approach for the treatment of cocaine addiction in active cocaine users. However, the decrease in irritability-like behavior during cocaine abstinence, together with previous findings showing that DBS of the NAcc shell reduces the reinstatement of cocaine seeking in abstinent animals, warrants future investigations of DBS as a treatment for negative emotional states and craving during abstinence.\n\nHighlightsO_LIHigh-frequency DBS of the NAcc shell for the treatment of cocaine addiction is proposed\nC_LIO_LIDBS of the NAcc shell does not decrease cocaine intake in cocaine-dependent rats\nC_LIO_LIDBS increases the level of GluR1 specifically in the central nucleus of the amygdala\nC_LI

neuroscience↗

bioRxiv2018

Heading direction with respect to a reference point modulates place-cell activity

Utilizing electrophysiological recordings from CA1 pyramidal cells in freely moving mice, we find that a majority of neural responses are modulated by the heading-direction of the animal relative to a point within or outside their enclosure that we call a reference point. Our findings identify a novel representation in the neuronal responses in the dorsal hippocampus.

neuroscience↗