Biology subjects

Bonito-Oliva, A.

Publications and source records attributed to Bonito-Oliva, A..

4 recordsLinked to original sources

bioRxiv2026

Lipid Activation of a Thalamic GPCR Extends Working Memory Time-scales

Working memory capacity is poorly understood. The ability to control and extend working memory time-scales provides the potential to alleviate cognitive decline in disease and aging. Through an unbiased genetic search, we previously identified a thalamic orphan receptor Gpr12 as a potent enhancer of working memory, however its activation mechanism remains poorly understood. Here, we describe the CryoEM structure of Gpr12, revealing a lipidic regulatory site enabling an activated signaling state. By surveying the native lipidic environment in mouse thalamus we identified a class of 20 carbon:4 double bond fatty acid eicosanoids as potential ligands. Cell-based assays confirmed that the endogenous cannabinoid anandamide (AEA), but not other closely related family members or derivatives, robustly activates Gpr12. In vivo imaging during behavior revealed that Gpr12 activation produces a striking molecular state - the persistent suppression of cAMP in thalamus that tracks the duration of memory maintenance. Notably, genetic or pharmacological manipulations that enhance the AEA-Gpr12 signaling axis are sufficient to prolong cAMP suppression and extend the temporal window of memory maintenance. Furthermore, AEA-mediated cAMP suppressions in thalamus support sustained neural activity in PFC, specifically during memory maintenance. Thus, while cannabinoids often impair memory, here we identify an AEA-Gpr12 signaling axis in thalamus that enhances memory, including in primates. These findings identify a lipidic signaling mechanism in thalamus that is sufficient to control and extend working memory duration.

neuroscience↗

bioRxiv2023

A Genetic Locus Mediating Attentional Processing

Attention is required for most higher-order cognitive functions. Prior studies have revealed functional roles for the prefrontal cortex and its extended circuits to enabling attention, but the underlying molecular processes and their impacts on cellular and circuit function remain poorly understood. To develop insights, we here took an unbiased forward genetics approach to identify single genes of large effect on attention. We studied 200 genetically diverse mice on measures of pre-attentive processing and through genetic mapping identified a small locus on chromosome 13 (95%CI: 92.22-94.09 Mb) driving substantial variation (19%) in this trait. Further characterization of the locus revealed a causative gene, Homer1, encoding a synaptic protein, where down-regulation of its short isoforms in prefrontal cortex (PFC) during early postnatal development led to improvements in multiple measures of attention in the adult. Subsequent mechanistic studies revealed that prefrontal Homer1 down-regulation is associated with GABAergic receptor up-regulation in those same cells. This enhanced inhibitory influence, together with dynamic neuromodulatory coupling, led to strikingly low PFC activity at baseline periods of the task but targeted elevations at cue onset, predicting short-latency correct choices. Notably high-Homer1, low-attentional performers, exhibited uniformly elevated PFC activity throughout the task. We thus identify a single gene of large effect on attention - Homer1 - and find that it improves prefrontal inhibitory tone and signal-to-noise (SNR) to enhance attentional performance. A therapeutic strategy focused on reducing prefrontal activity and increasing SNR, rather than uniformly elevating PFC activity, may complement the use of stimulants to improve attention.

neuroscience↗

bioRxiv2023

Anteromedial Thalamus Gates the Selection & Stabilization of Long-Term Memories

Memories initially formed in hippocampus gradually stabilize to cortex, over weeks-to-months, for long-term storage. The mechanistic details of this brain re-organization process remain poorly understood. In this study, we developed a virtual-reality based behavioral task and observed neural activity patterns associated with memory reorganization and stabilization over weeks-long timescales. Initial photometry recordings in circuits that link hippocampus and cortex revealed a unique and prominent neural correlate of memory in anterior thalamus that emerged in training and persisted for several weeks. Inhibition of the anteromedial thalamus-to-anterior cingulate cortex projections during training resulted in substantial memory consolidation deficits, and gain amplification more strikingly, was sufficient to enhance consolidation of otherwise unconsolidated memories. To provide mechanistic insights, we developed a new behavioral task where mice form two memories, of which only the more salient memory is consolidated, and also a technology for simultaneous and longitudinal cellular resolution imaging of hippocampus, thalamus, and cortex throughout the consolidation window. We found that whereas hippocampus equally encodes multiple memories, the anteromedial thalamus forms preferential tuning to salient memories, and establishes inter-regional correlations with cortex, that are critical for synchronizing and stabilizing cortical representations at remote time. Indeed, inhibition of this thalamo-cortical circuit while imaging in cortex reveals loss of contextual tuning and ensemble synchrony in anterior cingulate, together with behavioral deficits in remote memory retrieval. We thus identify a thalamo-cortical circuit that gates memory consolidation and propose a mechanism suitable for the selection and stabilization of hippocampal memories into longer term cortical storage.

neuroscience↗

bioRxiv2019

Discovery of conformation-sensitive anti-amyloid protofibril monoclonal antibodies using an engineered chaperone-like amyloid-binding protein

The hypothesis that amyloid beta peptides (A{beta}) are central to the pathogenesis of sporadic Alzheimers disease (AD) is still hotly debated. Although several monoclonal antibodies (mAbs) against A{beta} have failed in therapeutic clinical trials, two conformation-selective, anti-A{beta} mAbs continue to show promise. A significant challenge has been to discover mAbs that preferentially target A{beta} protofibrils over natively-folded monomeric peptides or amyloid plaques. We have engineered a novel chaperone-like amyloid-binding protein (CLABP), Nucleobindin 1 (NUCB1), which enables the stabilization of protofibrils, allowing them to be used as immunogens in mice to facilitate the generation of mAbs that recognize A{beta} protofibrils. An immunization campaign and subsequent screening funnel identified a panel of mAbs with high-affinity to A{beta}. Two mAbs in particular, 1A8 and 7C8, displayed significant conformation sensitivity and preferentially bound A{beta} protofibrils over monomers. Furthermore, 1A8 delayed A{beta} aggregation, but did not prevent eventual fibril formation, while 7C8 significantly and dose-dependently reduced fibril formation by inhibiting both primary and secondary nucleation. Both mAbs protected against protofibril-induced cytotoxicity in vitro, and showed distinctive staining patterns by immunohistochemistry in PS1/APP mice and in post-mortem AD brain tissue. In summary, we describe a novel method to stabilize soluble A{beta} protofibrils for use in immunization campaigns. We hypothesize that the stabilized protofibrils retain the neoepitopes of the A{beta} protofibril and the aggregates found in mouse models of disease and post-mortem AD brain tissue.

molecular biology↗