Acrylamide inhibits long-term potentiation and learning involving microglia and pro-inflammatory signaling (2022) Scientific Reports, 12 (1), art. no. 12429, .
Izumi, Y., Fujii, C.a, O’Dell, K.A. , Zorumski, C.F.
Acrylamide is a chemical used in various industries and a product following high-temperature cooking of vegetables containing asparagine. Environmental or dietary exposure to acrylamide could impair cognitive function because of its neurotoxicity. Using rat hippocampal slices, we tested whether acrylamide alters induction of long-term potentiation (LTP), a cellular model of learning and memory. We hypothesized that acrylamide impairs cognitive function via activation of pro-inflammatory cytokines because robust upregulation of NLRP3 inflammasome has been reported. Although acrylamide up to 3 mM did not alter basal synaptic transmission, incubation with 10 μM or acute administration of 100 μM acrylamide inhibited induction of LTP. Inhibitors of toll-like receptor 4 (TLR4), and minocycline, an inhibitor of microglial activation, overcame the effects of acrylamide on LTP induction. Furthermore, we observed that acrylamide failed to inhibit LTP after administration of MCC950, an inhibitor of NLRP3, or in the presence of Interleukin-1 receptor antagonist (IL-1Ra). We also found that in vivo acrylamide injection transiently impaired body weight gain and impaired one-trial inhibitory avoidance learning. This learning deficit was overcome by MCC950. These results indicate that cognitive impairment by acrylamide is mediated by mechanisms involving microglia and release of cytokines via NLRP3 activation. © 2022, The Author(s).
The cannabinoid agonist CB-13 produces peripherally mediated analgesia in mice but elicits tolerance and signs of central nervous system activity with repeated dosing (2022) Pain, 163 (8), pp. 1603-1621.
Slivicki, R.A., Yi, J. , Brings, V.E., Huynh, P.N. , Gereau, R.W.
Activation of cannabinoid receptor type 1 (CB1) produces analgesia in a variety of preclinical models of pain; however, engagement of central CB1receptors is accompanied by unwanted side effects, such as psychoactivity, tolerance, and dependence. Therefore, some efforts to develop novel analgesics have focused on targeting peripheral CB1receptors to circumvent central CB1-related side effects. In the present study, we evaluated the effects of acute and repeated dosing with the peripherally selective CB1-preferring agonist CB-13 on nociception and central CB1-related phenotypes in a model of inflammatory pain in mice. We also evaluated cellular mechanisms underlying CB-13-induced antinociception in vitro using cultured mouse dorsal root ganglion neurons. CB-13 reduced inflammation-induced mechanical allodynia in male and female mice in a peripheral CB1-receptor-dependent manner and relieved inflammatory thermal hyperalgesia. In cultured mouse dorsal root ganglion neurons, CB-13 reduced TRPV1 sensitization and neuronal hyperexcitability induced by the inflammatory mediator prostaglandin E2, providing potential mechanistic explanations for the analgesic actions of peripheral CB1receptor activation. With acute dosing, phenotypes associated with central CB1receptor activation occurred only at a dose of CB-13 approximately 10-fold the ED50for reducing allodynia. Strikingly, repeated dosing resulted in both analgesic tolerance and CB1receptor dependence, even at a dose that did not produce central CB1-receptor-mediated phenotypes on acute dosing. This suggests that repeated CB-13 dosing leads to increased CNS exposure and unwanted engagement of central CB1receptors. Thus, caution is warranted regarding therapeutic use of CB-13 with the goal of avoiding CNS side effects. Nonetheless, the clear analgesic effect of acute peripheral CB1receptor activation suggests that peripherally restricted cannabinoids are a viable target for novel analgesic development. © 2022 Lippincott Williams and Wilkins. All rights reserved.
Electro-mechanical coupling of KCNQ channels is a target of epilepsy-associated mutations and retigabine (2022) Science Advances, 8 (29), p. eabo3625.
Yang, N.-D., Kanyo, R., Zhao, L., Li, J., Kang, P.W., Dou, A.K., White, K.M., Shi, J., Nerbonne, J.M., Kurata, H.T., Cui, J.
KCNQ2 and KCNQ3 form the M-channels that are important in regulating neuronal excitability. Inherited mutations that alter voltage-dependent gating of M-channels are associated with neonatal epilepsy. In the homolog KCNQ1 channel, two steps of voltage sensor activation lead to two functionally distinct open states, the intermediate-open (IO) and activated-open (AO), which define the gating, physiological, and pharmacological properties of KCNQ1. However, whether the M-channel shares the same mechanism is unclear. Here, we show that KCNQ2 and KCNQ3 feature only a single conductive AO state but with a conserved mechanism for the electro-mechanical (E-M) coupling between voltage sensor activation and pore opening. We identified some epilepsy-linked mutations in KCNQ2 and KCNQ3 that disrupt E-M coupling. The antiepileptic drug retigabine rescued KCNQ3 currents that were abolished by a mutation disrupting E-M coupling, suggesting that modulating the E-M coupling in KCNQ channels presents a potential strategy for antiepileptic therapy.
An IL1RL1 genetic variant lowers soluble ST2 levels and the risk effects of APOE-ε4 in female patients with Alzheimer’s disease (2022) Nature Aging, 2 (7), pp. 616-634. Cited 1 time.
Jiang, Y., Zhou, X.,[…], Morris, J., Shaw, L.M., Khachaturian, Z., Sorensen, G., Kuller, L., Raichle, M., Paul, S., Davies, P., Fillit, H., Hefti, F., Holtzman, D., […], Ances, B., […], Masters, C.L., Fu, A.K.Y., Ip, N.Y., Alzheimer’s Disease Neuroimaging Initiative
Changes in the levels of circulating proteins are associated with Alzheimer’s disease (AD), whereas their pathogenic roles in AD are unclear. Here, we identified soluble ST2 (sST2), a decoy receptor of interleukin-33–ST2 signaling, as a new disease-causing factor in AD. Increased circulating sST2 level is associated with more severe pathological changes in female individuals with AD. Genome-wide association analysis and CRISPR–Cas9 genome editing identified rs1921622, a genetic variant in an enhancer element of IL1RL1, which downregulates gene and protein levels of sST2. Mendelian randomization analysis using genetic variants, including rs1921622, demonstrated that decreased sST2 levels lower AD risk and related endophenotypes in females carrying the Apolipoprotein E (APOE)-ε4 genotype; the association is stronger in Chinese than in European-descent populations. Human and mouse transcriptome and immunohistochemical studies showed that rs1921622/sST2 regulates amyloid-beta (Aβ) pathology through the modulation of microglial activation and Aβ clearance. These findings demonstrate how sST2 level is modulated by a genetic variation and plays a disease-causing role in females with AD. © 2022, The Author(s).