Disrupted presynaptic nectin1-based neuronal adhesion in the entorhinal-hippocampal circuit contributes to early-life stress-induced memory deficits.

The cell adhesion molecule nectin3 and its presynaptic partner nectin1 have been linked to early-life stress-related cognitive disorders, but how the nectin1-nectin3 system contributes to stress-induced neuronal, circuit, and cognitive abnormalities remains to be studied. Here we show that in neonatally stressed male mice, temporal order and spatial working memories, which require the medial entorhinal cortex (MEC)-CA1 pathway, as well as the structural integrity of CA1 pyramidal neurons were markedly impaired in adulthood. These cognitive and structural abnormalities in stressed mice were associated with decreased nectin levels in entorhinal and hippocampal subregions, especially reduced nectin1 level in the MEC and nectin3 level in the CA1.

GPR17 mediates ischemia-like neuronal injury via microglial activation.

GPR17 is a G (i)-coupled dual receptor, linked to P2Y and CysLT receptors stimulated by uracil nucleotides and cysteinyl leukotrienes, respectively. Recent evidence has demonstrated that GPR17 inhibition ameliorates the progression of cerebral ischemic injury by regulating neuronal death and microglial activation. The present study aimed to assess the detailed regulatory roles of this receptor in oxygen‑glucose deprivation/recovery (OGD/R)‑induced ischemia‑like injury in vitro and explore the underlying mechanism.

NAMPT inhibitor protects ischemic neuronal injury in rat brain via anti-neuroinflammation.

Nicotinamide phosphoribosyltransferase (NAMPT) is an important neuroprotective factor in cerebral ischemia, and it has been reported that NAMPT inhibitors can aggravate neuronal injury in the acute phase. However, because it is a cytokine, NAMPT participates in many inflammatory diseases in the peripheral system, and its inhibitors have therapeutic effects. Following cerebral ischemia, the peripheral and resident inflammatory and immune cells produce many pro-inflammatory mediators in the ischemic area, which induce neuroinflammation and impair the brain.

Specific cell surface labeling of GPCRs using split GFP.

Specific cell surface labeling is essential for visualizing the internalization processes of G-protein coupled receptors (GPCRs) and for gaining mechanistic insight of GPCR functions. Here we present a rapid, specific, and versatile labeling scheme for GPCRs at living-cell membrane with the use of a split green fluorescent protein (GFP). Demonstrated with two GPCRs, GPR17 and CysLT2R, we show that two β-stands (β-stands 10 and 11) derived from a superfolder GFP (sfGFP) can be engineered to one of the three extracellular loop of a GPCR.

[Effects of leukotriene D4 on proliferation and migration of lung epithelial A549 cells in vitro].

Objective: To investigate the effects of cysteinyl leukotriene (CysLT) receptor agonist leukotriene D4 (LTD4) on proliferation and migration in lung epithelial A549 cells.

Methods: The expression of CysLT1 receptor and CysLT2 receptor was determined by immunofluoresence staining in A549 cells. A549 cells were treated with LTD4 (0.

[Effects of the water channel aquaporin 4 deficiency on bleomycin-induced lung fibrosis in mice].

Objective: To evaluate the effect of water channel aquaporin 4 (AQP4) on bleomycin-induced lung fibrosis in mice.

Methods: In wild type and AQP4 gene knockout (AQP4-/-) mice, lung fibrosis was induced by injection of bleomycin (3 mg/kg) into the trachea and saline injection was used as a control. At d3, 7, 14, 28 after bleomycin-treatment, mice were randomly sacrificed in batch and the lung coefficient was determined.

[Effect of histone deacetylase inhibitor NL101 on rat neurons].

Objective: To investigate the protective effect of histone deacetylase inhibitor NL101 on L-homocysteine (HCA)-induced toxicity in rat neurons, and the toxic effect on normal rat neurons.

Methods: In the presence of NL101 at various concentrations, HCA (5 mmol/L)-induced changes in cell density, necrosis, and viability were determined in the mixed cultures of rat cortical cells and the primary cultures of rat neurons. The direct effect of NL101 on primary neurons was also observed in the absence of HCA.

[Antioxidative effects of cysteinyl leukotriene receptor antagonists montelukast and HAMI 3379 on ischemic injury in rat cortical neurons in vitro].

Objective: To investigate the antioxidative effects of two cysteinyl leukotriene receptors antagonists (CysLT1R and CysLT2R) montelukast and HAMI 3379 on ischemic injury of rat cortical neurons in vitro.

Methods: Cultured rat cortical neurons were pretreated with CysLT1R antagonist montelukast and CysLT2R antagonist HAMI 3379, and then exposed to oxygen-glucose deprivation/recovery (OGD/R）or H2O2. Reactive oxygen species (ROS) mitochondrial membrane potential (MMP) depolarization, neuronal viability and lactate dehydrogenase (LDH) release were determined.

Cysteinyl leukotriene receptor 1 mediates LTD4-induced activation of mouse microglial cells in vitro.

Aim: To investigate the roles of cysteinyl leukotriene receptors CysLT1R and CysLT2R in leukotriene D4 (LTD4)-induced activation of microglial cells in vitro.

Methods: Mouse microglial cell line BV2 was transfected with pcDNA3.1(+)-hCysLT1R or pcDNA3.

HAMI 3379, a CysLT2 receptor antagonist, attenuates ischemia-like neuronal injury by inhibiting microglial activation.

The cysteinyl leukotrienes (CysLTs) are inflammatory mediators closely associated with neuronal injury after brain ischemia through the activation of their receptors, CysLT1R and CysLT2R. Here we investigated the involvement of both receptors in oxygen-glucose deprivation/recovery (OGD/R)-induced ischemic neuronal injury and the effect of the novel CysLT2R antagonist HAMI 3379 [3-({[(1S,3S)-3- carboxycyclohexyl]amino}carbonyl)-4-(3-{4-[4-(cyclo-hexyloxy)butoxy]phenyl}propoxy)benzoic acid] in comparison with the CysLT1R antagonist montelukast. In primary neurons, neither the nonselective agonist leukotriene D4 (LTD4) nor the CysLT2R agonist N-methyl-leukotriene C4 (NMLTC4) induced neuronal injury, and HAMI 3379 did not affect OGD/R-induced neuronal injury.

Aggravated inflammation and increased expression of cysteinyl leukotriene receptors in the brain after focal cerebral ischemia in AQP4-deficient mice.

Objective: Aquaporin-4 (AQP4), the main water channel protein in the brain, plays a critical role in water homeostasis and brain edema. Here, we investigated its role in the inflammatory responses after focal cerebral ischemia.

Methods: In AQP4-knockout (KO) and wild-type mice, focal cerebral ischemia was induced by 30 min of middle cerebral arterial occlusion (MCAO).

Nuclear translocation of cysteinyl leukotriene receptor 1 is involved in oxygen-glucose deprivation-induced damage to endothelial cells.

Aim: Cysteinyl leukotriene receptor 1 (CysLT(1) receptor) is located in epithelial cells, and translocates from the plasma membrane to the nucleus in a ligand-dependent manner. Here, we investigated whether CysLT(1) receptors translocated to the nucleus in endothelial cells after ischemic insult in vitro and whether it was involved in ischemic injury to endothelial cells.

Methods: EA.

Intracerebroventricular injection of HAMI 3379, a selective cysteinyl leukotriene receptor 2 antagonist, protects against acute brain injury after focal cerebral ischemia in rats.

Cysteinyl leukotrienes (CysLTs) induce inflammatory responses by activating their receptors, CysLT(1)R and CysLT(2)R. We recently reported that CysLT(2)R is involved in neuronal injury, astrocytosis and microgliosis after focal cerebral ischemia in rats. Here, we determined whether HAMI 3379, a selective CysLT(2)R antagonist, protects against acute brain injury after focal cerebral ischemia in rats.

Transforming growth factor β1-induced astrocyte migration is mediated in part by activating 5-lipoxygenase and cysteinyl leukotriene receptor 1.

Background: Transforming growth factor-β 1 (TGF-β 1) is an important regulator of cell migration and plays a role in the scarring response in injured brain. It is also reported that 5-lipoxygenase (5-LOX) and its products, cysteinyl leukotrienes (CysLTs, namely LTC₄, LTD₄ and LTE₄), as well as cysteinyl leukotriene receptor 1 (CysLT₁R) are closely associated with astrocyte proliferation and glial scar formation after brain injury. However, how these molecules act on astrocyte migration, an initial step of the scarring response, is unknown.

[Effect of montelukast on morphological changes in neurons after ischemic injury].

Objective: To determine the effect of montelukast, a cysteinyl leukotriene receptor 1 antagonist, on morphological changes in rat neurons after ischemic injury.

Methods: The in vivo ischemia injury was induced by oxygen-glucose deprivation (OGD) for 2 h and reperfusion (R) for 24 h (OGD/R) in rat neurons primary culture and mixed cortex culture. In the presence or absence of various concentrations of montelukast, neuron number, area of neuron, number of neuritis per neuron, branch number of primary neuritis and primary neurite length were determined for evaluating morphological changes in neurons.

Aggravated chronic brain injury after focal cerebral ischemia in aquaporin-4-deficient mice.

The water channel aquaporin-4 (AQP4) is important in brain water homeostasis, and is also involved in astrocyte growth and glial scar formation. It has been reported that AQP4 deficiency attenuates acute ischemic brain injury as a result of reducing cytotoxic edema. Here, we determined whether AQP4 deficiency influences chronic brain injury after focal cerebral ischemia induced by 30 min of middle cerebral artery occlusion (MCAO).

Aquaporin-4 deficiency attenuates acute lesions but aggravates delayed lesions and microgliosis after cryoinjury to mouse brain.

Objective: To determine whether aquaporin-4 (AQP4) regulates acute lesions, delayed lesions, and the associated microglial activation after cryoinjury to the brain.

Methods: Brain cryoinjury was applied to AQP4 knockout (KO) and wild-type mice. At 24 h and on days 7 and 14 after cryoinjury, lesion volume, neuronal loss, and densities of microglia and astrocytes were determined, and their changes were compared between AQP4 KO and wild-type mice.

Anti-proliferation effect of APO866 on C6 glioblastoma cells by inhibiting nicotinamide phosphoribosyltransferase.

Nicotinamide phosphoribosyltransferase (NAMPT) is a key enzyme in the salvaging pathway for the synthesis of nicotinamide adenine dinucleotide (NAD) that is involved in cell metabolism and proliferation. NAMPT is normally absent in astrocyte but highly expressed in glioblastoma, suggesting that it may promote cell survival through synthesizing more NAD. In this report, we evaluated the effect of APO866, a potent inhibitor of NAMPT against C6 glioblastoma.

[Deficiency of water channel AQP4 aggravates NMDA-induced brain injury in mice].

Objective: To evaluate the role of water channel AQP4 in NMDA-induced brain injury in mice.

Methods: In AQP4 gene knockout (AQP4(-/-)) mice, brain injury was induced by microinjection of NMDA into the cortex. The injured area was determined by toluidine blue staining, degenerated neurons were detected by Fluro-Jade B staining, and increased blood-brain barrier (BBB) permeability was evaluated by IgG immunostaining.

[Effects of agonist and antagonist of cysteinyl leukotriene receptors on differentiation of rat glioma C6 cells].

Objective: To investigate the role of cysteinyl leukotriene (CysLT) receptors in the differentiation of rat glioma C6 cells.

Methods: Rat glioma C6 cells were treated with the agonist LTD(4), the CysLT(1) receptor antagonist montelukast and the differentiation inducer forskolin. Cell morphology and GFAP protein expression were determined after treatments.

[Rotenone-induced changes of cysteinyl leukotriene receptor 1 expression in BV2 microglial cells].

Objective: To prepare and identify a polyclonal antibody (pAb) against (mouse) cysteinyl leukotriene receptor 1 (CysLT(1)) and to investigate the changes of CysLT(1) receptor expression in BV2 microglial cells after rotenone treatment.

Methods: Rabbits were immunized with KLH-coupled CysLT(1) peptide to prepare the pAb. The titer of the pAb in rabbit plasma was detected by ELISA method, and the specificity of the pAb was tested by antigen blockade.

[Construction of HEK293 cell lines expressing hCysLT₂ receptor and its application in screening of antagonists].

Objective: To construct HEK293 cell lines stably expressing hCysLT(2) receptor, and to evaluate its application in screening of synthetic compounds with antagonist activity.

Methods: The recombinant plasmid pcDNA3.1(+)-hCysLT(2) was transfected into HEK293 cells using Lipofectamin 2000.

Montelukast, a cysteinyl leukotriene receptor-1 antagonist, attenuates chronic brain injury after focal cerebral ischaemia in mice and rats.

Objectives: Previously we demonstrated the neuroprotective effect of montelukast, a cysteinyl leukotriene receptor-1 (CysLT(1) ) antagonist, on acute brain injury after focal cerebral ischaemia in mice. In this study, we have determined its effect on chronic brain injury after focal cerebral ischaemia in mice and rats.

Methods: After transient focal cerebral ischaemia was induced by middle cerebral artery occlusion, montelukast was intraperitoneally injected in mice or orally administered to rats for five days.

Pranlukast attenuates hydrogen peroxide-induced necrosis in endothelial cells by inhibiting oxygen reactive species-mediated collapse of mitochondrial membrane potential.

Objective: Recently, we reported that pranlukast, an antagonist of cysteinyl leukotriene receptor 1, attenuates ischemic injury in endothelial cells by decreasing reactive oxygen species (ROS) production and inhibiting nuclear factor-κB activation in a leukotriene-independent manner. In this study, we investigated the effect of pranlukast on oxidative stress injury induced by hydrogen peroxide (H2O2) in EA.hy926 cells, a human endothelial cell line, and the possible mechanisms.

CysLT2 receptor-mediated AQP4 up-regulation is involved in ischemic-like injury through activation of ERK and p38 MAPK in rat astrocytes.

Aims: We previously reported that cysteinyl leukotriene receptor 2 (CysLT(2)) mediates ischemic astrocyte injury, and leukotriene D(4)-activated CysLT(2) receptor up-regulates the water channel aquaporin 4 (AQP4). Here we investigated the mechanism underlying CysLT(2) receptor-mediated ischemic astrocyte injury induced by 4-h oxygen-glucose deprivation and 24-h recovery (OGD/R).

Main Methods: Primary cultures of rat astrocytes were treated by OGD/R to construct the cell injury model.