Biology subjects

Ramirez de Mingo, D.

Publications and source records attributed to Ramirez de Mingo, D..

4 recordsLinked to original sources

bioRxiv2025

An anti-amyloidogenic approach to specifically block memory consolidation in mice for therapeutic intervention

Post-traumatic stress disorder (PTSD) is a mental health disorder triggered by the exposure to a traumatic event, which manifests with anguish, intrusive memories, and negative mood changes. So far, there is no efficient treatment for PTSD other than symptomatic palliative care. However, the cytoplasmic polyadenylation element binding protein-3 (CPEB3) has been recently associated to a potential risk gene for PTSD. Considering that CPEB3 protein is a functional amyloid whose importance for long-term memory consolidation in mammals is well established, we propose the active (amyloid) state of CPEB3 as a promising therapeutic target to block the consolidation of traumatic memories through by the anti-amyloidogenic polyglutamine binding peptide 1 (QBP1). Here we report a preclinical development in mice of this pharmacological treatment for PTSD based on the action of the QBP1 peptide. We first characterized the human CPEB3 (hCPEB3) protein in vitro, showing how its amyloid aggregation is inhibited by the active core of QBP1 (QBP1-M8) without affecting other self-assembly processes such as phase separation. Then, we generated and characterized a novel transgenic mouse that constitutively expresses QBP1 in tandem (TgQBP1). TgQBP1 mice have shown that the consolidation of simple learning is impaired after 24 h for both hippocampal-dependent and aversive memories and that it is limited to new learned memories and has no effect on short-term memory. Furthermore, fear induced anxiety was reduced in comparison to WT mice, suggesting that PTSD-like symptoms are also being ameliorated. Intriguingly, we found that aversive memories seem to be more strongly affected in younger mice. Finally, the analysis of CPEB3 amyloid presence in hippocampal extracted samples showed a correlative decrease in murine CPEB3 oligomerization in the TgQBP1 mice. Taking together, these results strongly suggest that the amyloidogenic blockage of CPEB3 by QBP1 peptide is a potential drug for the prevention and treatment of PTSD.

neuroscience↗

bioRxiv2020

Molecular determinants of liquid demixing and amyloidogenesis in human CPEB3

The cytoplasmic polyadenylation element-binding protein 3 (CPEB3), is an RNA-binding protein which in its soluble state is localized in membraneless neuronal RNA granules keeping target mRNAs in a repressed state. The stimulus-dependent aggregation of CPEB3 activates target mRNAs translation, a central event for the maintenance of long-term memory-related synaptic plasticity in mammals. To date, the molecular determinants that govern both connected events remain unclear. Here, to gain insight into these processes, the biophysical properties of the human CPEB3 (hCPEB3) are characterized. We found that hCPEB3 homotypic condensation is mainly driven by hydrophobic interactions and occurs under physiological conditions. Moreover, hCPEB3 biomolecular condensates are dynamic inside living cells, whose localization and stabilization are mediated by its RNA-recognition domains. In contrast, the hCPEB3 polar N-terminal region is crucial for hCPEB3 amyloid-like aggregation in vitro, which is disrupted by the polyglutamine binding peptide 1 (QBP1), A{beta}42 seeds and Hsp70, highlighting the importance of the Q4RQ4 tract as well as the hydrophobic residues for hCPEB3 functional aggregation. Based on these findings, we postulate a model for hCPEB3s role in memory persistence that advances a rather sophisticated control for hCPEB3 condensate dissociation and amyloid-like formation to achieve its physiological function. HighlightsO_LIhCPEB3 forms toxic intermediates that persist longer than in other functional amyloids. C_LIO_LIRNA-recognition domains stabilize hCPEB3 granule formation and dynamics. C_LIO_LIDifferent segments within hCPEB3 promote amyloidogenesis and liquid demixing. C_LIO_LIhCPEB3 amyloid formation requires both hydrophobic and polyQ segments. C_LI Graphical Abstract O_FIG_DISPLAY_L [Figure 1] M_FIG_DISPLAY C_FIG_DISPLAY

neuroscience↗

bioRxiv2020

Preferred Conformations in the Intrinsically Disordered Region of Human CPEB3 Explain its Role in Memory Consolidation

While implicated in neurodegenerative diseases, amyloids are also essential to some physiological processes, including memory consolidation by neuronal-specific isoforms of the Cytoplasmic Polyadenylation Element Binding (CPEB) protein family. CPEB mediates memory persistence by the formation of self-sustaining amyloid assemblies through its intrinsically disordered region (IDR). Here, we characterize the atomic level conformation and ps-ns dynamics of the 426-residue IDR of human CPEB3 (hCPEB3), which has been associated with episodic memory in humans, by NMR spectroscopy. We found that the first 29 residues: M1QDDLLMDKSKTQPQPQQQQRQQQQPQP29, adopt a helical+disordered motif. Residues 86-93: P83QQPPPP93, and 166-175: P166PPPAPAPQP175 form polyproline II (PPII) helices. While the (VG)5 repeat motif is completely disordered, residues 200-250 adopt three partially populated -helices. Residues 345-355, which comprise the nuclear localization signal (NLS), form a modestly populated -helix and border a phosphoTyr which may mediate STAT5B binding. These findings allow us to suggest a model for nascent hCPEB3 structural transitions at single residue resolution, advancing that amyloid breaker residues, like proline, are a key difference between functional versus pathological amyloids. Besides revealing some aspects of the molecular basis of memory, these findings could aid the future development of treatments for post-traumatic stress disorder. Areas: Biophysics, Structural Biology, Biochemistry & Neurosciences.

biochemistry↗

bioRxiv2020

An Anti-amyloidogenic treatment to specifically block the consolidation of traumatic events in mouse

Post-traumatic stress disorder (PTSD) is a mental health disorder triggered by the exposure to a traumatic event that manifests with anguish, intrusive memories and negative mood changes. So far, there is no efficient treatment for PTSD other than symptomatic palliative care. Based on the implication of the functional amyloid cytoplasmic polyadenylation element binding protein-3 (CPEB3) in the consolidation of memory, we propose its active amyloid state as a possible therapeutic target by blocking the consolidation of traumatic memories through polyglutamine binding peptide 1 (QBP1), an inhibitor of the amyloid oligomerization previously investigated in Drosophila. To test this idea in mammals, here we have developed a transgenic mouse that constitutively expresses QBP1 peptide. We first assessed the innocuousness of this peptide for the normal development of the animal, which also showed normal locomotor activity and anxiety. By performing a battery of standard memory paradigms, we then showed that hippocampal-dependent and aversive memories were impaired in the QBP1 mice. Furthermore, protein expression in the hippocampi of experienced mice showed that QBP1 mice do not increase their levels of amyloid oligomerization, evincing the blockade of the CPEB3 protein in its inactive state. The ability of QBP1 to block aversive memories in mice represents the proof of concept of a novel pharmacological approach for prophylaxis and therapy of acute stress and post-traumatic stress disorders.

animal behavior and cognition↗