Biology subjects

Peinado, J. R.

Publications and source records attributed to Peinado, J. R..

2 recordsLinked to original sources

bioRxiv2026

Exploratory spatial peptidomic profiling during incubation of drug seeking following cocaine plus alcohol self-administration in young adult rats

BackgroundConcurrent cocaine and alcohol use is one of the most prevalent forms of polysubstance consumption and is associated with poorer clinical outcomes than cocaine use alone. However, the regional molecular adaptations induced by combined exposure remain poorly understood. Here, we used matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS) to characterize peptide/protein alterations in addiction-related brain regions following cocaine and cocaine-alcohol self-administration. MethodsYoung adult male and female Wistar rats underwent intravenous self-administration of saline, cocaine (1 mg/kg/infusion) or cocaine plus ethanol (1 mg/kg cocaine and 133 mg/kg ethanol per infusion), followed by extinction of drug-seeking behaviour. Coronal brain sections containing the anterior cingulate cortex (ACC) and ventral hippocampus (vHPC) were analysed by MALDI-IMS. Differential molecular features were identified using an exploratory statistical approach (FDR q < 0.20) and subsequently subjected to MS/MS analysis. ResultsThe ACC exhibited a substantially greater number of treatment-associated molecular alterations than the vHPC, suggesting a higher regional susceptibility to cocaine-induced molecular remodelling. Several molecular features were shared between the cocaine and cocaine-alcohol groups, indicating persistent cocaine-driven neuroadaptations. In contrast, additional signals were selectively associated with combined cocaine-alcohol exposure, while others present after cocaine alone were absent following alcohol co-exposure, supporting a modulatory effect of alcohol on specific cocaine-induced molecular responses. Overall, combined exposure generated a distinct regional molecular profile rather than simply reproducing the effects of cocaine alone. ConclusionsThis exploratory study demonstrates that MALDI-IMS enables the identification of region-specific peptide/protein alterations associated with cocaine and cocaine-alcohol exposure while preserving their spatial distribution within the brain. These findings highlight the ACC as a particularly responsive region and provide a framework for future studies aimed at validating molecular pathways involved in cocaine-alcohol polysubstance use.

neuroscience↗

bioRxiv2020

Phase separation of proSAAS into spheres results in core sequestration of TDP-43216-414 aggregates

As neurons age, protein homeostasis becomes less efficient, resulting in misfolding and aggregation. Chaperone proteins perform vital functions in the maintenance of cellular proteostasis, and chaperone-based therapies that promote sequestration of toxic aggregates may prove useful in blocking the development of neurodegenerative disease. We previously demonstrated that proSAAS, a small secreted neuronal protein, exhibits potent chaperone activity against protein aggregation in vitro, and blocks the cytotoxic effects of amyloid and alpha synuclein oligomers in cell culture models. We now examine whether cytoplasmic expression of proSAAS results in interaction with protein aggregates in this cellular compartment. We used site-directed mutagenesis, confocal microscopy, in vitro aggregation assays, and functional assays to investigate the interaction of proSAAS with TDP-43 and other known aggregating proteins. We report that expression of proSAAS within the cytoplasm generates dense, membrane-less 2 m proSAAS spheres which progressively fuse to form larger spheres, suggesting liquid droplet-like properties. ProSAAS spheres selectively accumulate a C-terminally truncated fluorescently-tagged form of TDP-43216-414, initiating its cellular redistribution by sequestration within the sphere core; these TDP-43216-414 -containing spheres also exhibit dynamic fusion. Removal of either the predicted -helix (37-70) composed of hydrophobic and charged amino acids or the stretch of amino acids encompassing the conserved hydrophobic region and the positively charged furin site (163-189) inhibits the ability of proSAAS both to form spheres and to encapsulate TDP-43 aggregates. As a functional output, we demonstrate that proSAAS expression results in cytoprotection against full-length TDP-43 toxicity in yeast. In summary, the normally secreted neuronal chaperone proSAAS, when expressed in the cytoplasm unexpectedly phase-separates to form spherical liquid-like condensates that undergo dynamic fusion. We conclude that cyto-proSAAS acts as a functional holdase for cytoplasmic TDP-43216-414 molecules via this phase-separation property, representing a cytoprotectant whose unusual biochemical properties can potentially be exploited in the design of therapeutic molecules.

neuroscience↗