Biology subjects

Shan, Z.

Publications and source records attributed to Shan, Z..

40 records · Page 3Linked to original sources

bioRxiv2020

Production of the Short Chain Fatty Acid, Acetic Acid/Acetate from Ethanol Metabolism Activates NMDAR

Binge alcohol consumption elicits robust sympathoexcitation and excitatory neuronal output. However, the central mechanism that mediates these effects remains elusive. We investigated the effects of ethanol metabolism within the central nucleus of the amygdala (CeA) on sympathoexcitation, and elucidated the role of acetate in these excitatory responses. In vivo arterial blood pressure, heart rate and sympathetic nerve activity responses to CeA microinjected ethanol or acetate with appropriate inhibitors/antagonists were tracked. In vitro whole-cell electrophysiology recording responses to acetate in CeA neurons with axon projecting to the rostral ventrolateral medulla (CeA-RVLM) were investigated, and cytosolic calcium responses in primary neuronal cultures were quantified. We demonstrate that in Sprague Dawley rats, local brain metabolism of ethanol in the CeA to acetic acid/acetate elicits sympathoexcitatory responses in vivo through activation of NMDA receptor (NMDAR). Alcohol dehydrogenase or aldehyde dehydrogenase inhibition using fomepizole or cyanamide and NMDAR antagonism using AP5 or memantine blunted these effects. Whole-cell patch-clamp recordings in brain slices containing autonomic CeA-RVLM neurons revealed a dose-dependent increase in neuronal excitability in response to acetate. NMDAR antagonists suppressed the acetate-induced increase in CeA-RVLM neuronal excitability, and memantine suppressed the direct activation of NMDAR-mediated inward currents by acetate in brain slices. We observed that acetate increased cytosolic Ca2+ in a time-dependent manner in primary neuronal cell cultures. The acetate enhancement of calcium signaling was abolished by memantine. These findings suggest that within the CeA, ethanol is sympathoexcitatory through local brain metabolism, which generates acetic acid/acetate leading to activation of NMDAR. NEW AND NOTEWORTHYBrain ethanol metabolism to acetic acid (vinegar)/acetate causes activation of N-methyl-D-aspartate receptors (NMDARs) in the central nucleus of the amygdala and elicits sympathoexcitatory responses. This excitatory mechanism is opposite to the inhibitory effects of ethanol at NMDAR. Understanding the active compounds that arise from ethanol metabolism, and the molecular mechanisms by which they influence alcohol reward and cardiovascular function, may be beneficial in developing targeted intervention strategies for both alcohol use disorder and its cardiovascular sequelae. Graphical Figure O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=172 SRC="FIGDIR/small/212597v4_ufig1.gif" ALT="Figure 1"> View larger version (36K): org.highwire.dtl.DTLVardef@18d8ec9org.highwire.dtl.DTLVardef@996b70org.highwire.dtl.DTLVardef@5cbecaorg.highwire.dtl.DTLVardef@f1cd4b_HPS_FORMAT_FIGEXP M_FIG Proposed mechanisms for ethanol and acetate induced increases in sympathoexcitation within the central nucleus of the amygdala (CeA). Abbreviations: Acetic acid (HOAc), acetate (-OAc), ADH (alcohol dehydrogenase), ALDH (aldehyde dehydrogenase), BBB (blood brain barrier), FOM (fomepizole), CYAN (cyanamide), CYP450 (cytochrome P450), IML (intermediolateral nucleus), RVLM (rostral ventrolateral medulla), SNA (sympathetic nerve activity). C_FIG

physiology↗

bioRxiv2020

Studies on CRMP2 SUMOylation-deficient transgenic mice identify sex-specific NaV1.7 regulation in the pathogenesis of chronic neuropathic pain

The sodium channel NaV1.7 is a master regulator of nociceptive neuronal firing. Mutations in this channel can result in painful conditions as well as produce insensitivity to pain. Despite being recognized as a "poster child" for nociceptive signaling and human pain, targeting NaV1.7 has not yet produced a clinical drug. Recent work has illuminated the NaV1.7 interactome, offering insights into the regulation of these channels and identifying potentially new druggable targets. Amongst the regulators of NaV1.7 is the cytosolic collapsin response mediator protein 2 (CRMP2). CRMP2, modified at Lysine 374 (K374) by addition of a small ubiquitin-like modifier (SUMO), bound NaV1.7 to regulate its membrane localization and function. Corollary to this, preventing CRMP2 SUMOylation was sufficient to reverse mechanical allodynia in rats with neuropathic pain. Notably, loss of CRMP2 SUMOylation did not compromise other innate functions of CRMP2. To further elucidate the in vivo role of CRMP2 SUMOylation in pain, we generated CRMP2 K374A knock-in (CRMP2K374A/K374A) mice in which Lys374 was replaced with Ala. CRMP2K374A/K374A mice had reduced NaV1.7 membrane localization and function in female, but not male, sensory neurons. Behavioral appraisal of CRMP2K374A/K374A mice demonstrated no changes in depressive or repetitive, compulsive-like behaviors, and a decrease in noxious thermal sensitivity. No changes were observed in CRMP2K374A/K374A mice to inflammatory, acute, or visceral pain. In contrast, in a neuropathic model, CRMP2K374A/K374A mice failed to develop persistent mechanical allodynia. Our study suggests that CRMP2 SUMOylation-dependent control of peripheral NaV1.7 is a hallmark of chronic, but not physiological, neuropathic pain.

neuroscience↗

bioRxiv2020

De novo protein synthesis in distinct centrolateral amygdala interneurons is required for associative emotional memories

To survive in a dynamic environment, animals need to identify and appropriately respond to stimuli that signal danger1,2. At the same time, animal survival also depends on suppressing the threat response during a stimulus that predicts absence of threat, i.e. safety3-5. Understanding the biological substrates of differential threat memories in which animals learn to flexibly switch between expressing and suppressing defensive responses to a threat-predictive cue and a safety cue, respectively, is critical for developing treatments for memory disorders such as PTSD6. A key brain area for processing and storing threat memories is the centrolateral amygdala (CeL), which receives convergent sensory inputs from the parabrachial nucleus and the basolateral amygdala and connects directly to the output nucleus of amygdala, the centromedial nucleus, to mediate defensive responses7-9. Despite a plethora of studies on the importance of neuronal activity in specific CeL neuronal populations during memory acquisition and retrieval10-12, little is known about regulation of their protein synthesis machinery. Consolidation of long-term, but not short-term, threat memories requires de novo protein synthesis, which suggests that the translation machinery in CeL interneurons is tightly regulated in order to stabilize associative memories. Herein, we have applied intersectional chemogenetic strategies in CeL interneurons to block cell type-specific translation initiation programs that are sensitive to depletion of eukaryotic initiation factor 4E (eIF4E) and phosphorylation of eukaryotic initiation factor 2 (p-eIF2), respectively. We show that in a differential threat conditioning paradigm, de novo translation in somatostatin-expressing (SOM) interneurons in the CeL is necessary for long-term storage of conditioned threat response whereas de novo translation in protein kinase C{delta}-expressing (PKC{delta}) interneurons in the CeL is essential for storing conditioned response inhibition to a safety cue. Further, we show that oxytocinergic neuromodulation of PKC{delta} interneurons during differential threat learning is important for long-lasting cued threat discrimination. Our results indicate that the molecular elements of a differential threat memory trace are compartmentalized in distinct CeL interneuron populations and provide new mechanistic insight into the role of de novo protein synthesis in consolidation of long-term memories.

neuroscience↗

bioRxiv2020

Circ_0005962 functions as an oncogene to aggravate non-small cell lung cancer progression via circ_0005962/miR-382-5p/PDK4 regulatory network

Non-small cell lung cancer (NSCLC) is a leading threat to human lives with high incidence and mortality. Circular RNAs (circRNAs) were reported to play important roles in human cancers. The purpose of this study was to investigate the role of circ_0005962 and explore the underlying functional mechanisms. The expression of circ_0005962, miR-382-5p and pyruvate dehydrogenase kinase 4 (PDK4) was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation and cell apoptosis were assessed by cell counting kit-8 (CCK-8) assay and flow cytometry assay, respectively. The protein levels of Beclin 1, light chain3 (LC3-II/LC3-I), PDK4, Cleaved Caspase 3 (C-caspase 3) and proliferating cell nuclear antigen (PCNA) were examined using western blot analysis. Glycolysis was determined according to the levels of glucose consumption and lactate production. The interaction between miR-382-5p and circ_0005962 or PDK4 was predicted by the online tool CircInteractome or starbase and verified by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. Xenograft model was constructed to investigate the role of circ_0005962 in vivo. circ_0005962 expressed with a high level in NSCLC tissues and cells. Circ_0005962 knockdown inhibited proliferation, autophagy, and glycolysis but promoted apoptosis in NSCLC cells. MiR-382-5p was targeted by circ_0005962, and its inhibition reversed the role of circ_0005962 knockdown. Besides, PDK4, a target of miR-382-5p, was regulated by circ_0005962 through miR-382-5p, and its overexpression abolished the effects of miR-382-5p reintroduction. Circ_0005962 knockdown suppressed tumor growth in vivo. Circ_0005962 knockdown restrained cell proliferation, autophagy, and glycolysis but stimulated apoptosis through modulating the circ_0005962/miR-382-5p/PDK4 axis. Our study broadened the insights into understanding the mechanism of NSCLC progression.

cell biology↗