Panx1 Ablation Aggravates Oxidative Stress and Cell Death by Altering AMPK/mTOR signaling Pathways and the Composition of Synapses in the Zebrafish

Abstract

Pannexin-1 channels have garnered attention for their implications in neurodevelopment, potentially having a dual role in mediating a delicate balance between cell death and survival. However, a comprehensive understanding of the underlying molecular and cellular mechanisms and Panx1s potential protective functions throughout neurodevelopment remains to be determined. Zebrafish larvae with loss of Pannexin-1a function were subjected to an acute exposure to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Early-life changes in larvae induced by uncoupling of oxidative phosphorylation were investigated by a computational Gene Set Expression Analysis of RNA-seq data and experimental testing of light-stimulated locomotor behavior, cell death, and bioelectrical properties of local field potentials in the ascending visual pathway. A KEGG pathway analysis underscored Panx1as regulatory influence on neurodevelopment. Targeting Panx1a caused a deregulation of oxidative phosphorylation, glycolysis, reactive oxygen production, hypoxia, unfolded protein response pathways, and reduced extracellular ATP. Further, Panx1a ablation enhanced the transcriptional activation of 5 AMP-activated protein kinase (AMPK) kinase, a cellular energy sensor activated by falling energy status, largely to activate glucose and fatty acid uptake and oxidation when cellular energy is low. The activation of the AMPK pathway in Panx1a knock-out larvae correlated with the stimulation of the mammalian target of rapamycin (mTORC1) pathway that controls cellular metabolism, catabolism, immune responses, autophagy, survival, proliferation, and migration, to maintain cellular homeostasis. The differential expression of mTORC1 pathway genes associated with autophagy, and apoptosis signaling pathways. The resultant cell death was pronounced in the pallium and tectum regions. The loss of cells interrelated with a trans-synaptic a loss of synaptic neurotransmitter receptor and ion channel/transporter expression. Local field potential recordings in the optic tectum and pallium demonstrated that Panx1as involvement in modulating local neuronal networks was altered. Collectively, the results shed light on the impacts of acute MPTP treatment on locomotor behavior, transcriptomic shifts, metabolic disturbances, and the pivotal role of Panx1a in cell death. These insights enhance our comprehension of the intricate molecular and cellular mechanisms underpinning neurodevelopment, with implications for potential therapeutic strategies targeting Panx1 channels in autism and Alzheimers disease. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=172 HEIGHT=200 SRC="FIGDIR/small/590821v2_ufig1.gif" ALT="Figure 1"> View larger version (40K): org.highwire.dtl.DTLVardef@1a8688eorg.highwire.dtl.DTLVardef@16849a3org.highwire.dtl.DTLVardef@1ba8298org.highwire.dtl.DTLVardef@1d3efff_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIA genetic model was combined with the neurotoxin MPTP to explore the roles of zebrafish Pannexin-1 channels in neurodevelopment under oxidative stress conditions. C_LIO_LIA potential beneficial impact of targeting Panx1a is superseded by synaptic plasticity loss, dysfunctional mitochondrial metabolism, and cell death pathway activation. C_LIO_LILoss of Panx1a amplifies AMPK/mTORC1 pathway activation of cell death pathways. C_LIO_LIA role of Panx1a as a regulator of energy and synaptic homeostasis was identified. C_LI