The neuronal loss caused by excessive glutamate release, or 'excitotoxicity', leads to several pathological conditions, including cerebral ischemia, epilepsy, and neurodegenerative diseases. Over-stimulation of presynaptic N-methyl-D-aspartate (NMDA) receptors is known to trigger and support glutamate spillover, while postsynaptic NMDA receptors are responsible for the subsequent apoptotic cascade. Almost all molecules developed so far are unable to selectively block presynaptic or postsynaptic NMDA receptors, therefore a deeper knowledge about intracellular NMDA pathways is required to design more specific inhibitors. Our previous work showed that presynaptic c-Jun N-terminal kinase 2 (JNK2) specifically regulates NMDA-evoked glutamate release and here we demonstrate that an interaction between Syntaxin-1a and JNK2 is fundamental to this mechanism. Based on this evidence, a new cell permeable peptide (CPP), "JGRi1", has been developed to disrupt the JNK2/STX1a interaction to indirectly, but specifically, inhibit presynaptic NMDA receptor signaling. JGRi1 reduces the NMDA-evoked release of glutamate both in in-vitro and ex-vivo experiments while also being able to widely diffuse throughout brain tissue via intraperitoneal administration. In conclusion, the JNK2/STX1 interaction is involved in presynaptic NMDA-evoked glutamate release and the novel CPP, JGRi1, acts as a pharmacological tool that promotes neuroprotection.
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http://dx.doi.org/10.1038/s41598-019-43709-2 | DOI Listing |
Proc Natl Acad Sci U S A
January 2025
Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, CA 94720.
Norepinephrine in vertebrates and its invertebrate analog, octopamine, regulate the activity of neural circuits. We find that, when hungry, larvae switch activity in type II octopaminergic motor neurons (MNs) to high-frequency bursts, which coincide with locomotion-driving bursts in type I glutamatergic MNs that converge on the same muscles. Optical quantal analysis across hundreds of synapses simultaneously reveals that octopamine potentiates glutamate release by tonic type Ib MNs, but not phasic type Is MNs, and occurs via the G-coupled octopamine receptor (OAMB).
View Article and Find Full Text PDFFASEB J
January 2025
Department of Eye Center, Xiangya Hospital, Central South University, Changsha, China.
Fatty acid binding proteins (FABPs) are a class of small molecular mass intracellular lipid chaperone proteins that bind to hydrophobic ligands, such as long-chain fatty acids. FABP5 expression was significantly upregulated in the N-methyl-d-aspartic acid (NMDA) model, the microbead-induced chronic glaucoma model, and the DBA/2J mice. Previous studies have demonstrated that FABP5 can mediate mitochondrial dysfunction and oxidative stress in ischemic neurons, but the role of FABP5 in oxidative stress and cell death in retina NMDA injury models is unclear.
View Article and Find Full Text PDFToxicon
January 2025
Universidade Estadual do Oeste do Paraná, Programa de Pós-Graduação em Biociências e Saúde (PPG-BCS) - Cascavel, Brazil. Electronic address:
This study investigated the effects of a novel bombesin-related peptide (BR-b), derived from the skin of the Chaco tree frog (Boana raniceps), on glucose homeostasis in non-obese and hypothalamic-obese male rats. Hypothalamic obesity was induced in neonatal rats through high-dose administration of monosodium glutamate (MSG; 4 g/kg), while control animals (CTL) received an equimolar saline solution. At 70 days of age, both MSG and CTL groups underwent an oral glucose tolerance test (OGTT; 2 g/kg) with or without prior intraperitoneal administration of BR-b at doses of 0.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
University Hospital Bonn, Bonn, Germany
Background: Our laboratory has demonstrated that the NLRP3 inflammasome has a critical role in the microglial innate immune response to Alzheimer’s disease (AD)‐related peptides, triggering the release of cleaved‐caspase‐1 and IL‐1β. NLRP3 activation was found in post‐mortem tissue from individuals with AD (Heneka et al., 2013) and in transgenic models of AD (APP/PS1 mice).
View Article and Find Full Text PDFAlzheimers Dement
December 2024
Vaccinex, Inc., Rochester, NY, USA
Background: The earliest recognized biomarker of AD is deposition of Aβ amyloid that leads to formation of plaques and may, over time, trigger or at least be followed by gliosis/neuroinflammation and neurofibrillary tangles, accompanied by neurodegenerative changes including neuronal and synaptic loss. We have previously reported that semaphorin 4D (SEMA4D), the major ligand of plexin B receptors expressed on astrocytes, is upregulated in diseased neurons during progression of AD and Huntington’s disease (HD). Binding of SEMA4D to PLXNB receptors triggers astrocyte reactivity, leading to loss of neuroprotective homeostatic functions, including downregulation of glutamate and glucose transporters (doi:10.
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