Effects of Exercise Training on Immune-Related Genes and Pathways in the Cortex of Animal Models of Alzheimer's Disease: A Systematic Review.

Background: Alzheimer's disease (AD) is a chronic neurodegenerative disease that affects the immune system due to the accumulation of amyloid-ß (Aß) and tau associated molecular pathology and other pathogenic processes. To address AD pathogenesis, various approaches had been conducted from drug development to lifestyle modification to reduce the prevalence of AD. Exercise is considered a prominent lifestyle modification to combat AD. Objective: This observation prompted us to review the literature on exercise related to immune genes in the cortex of animal models of AD. We focused on animal model studies due to their prevalence in this domain. Methods: The systematic review was conducted according to PRISMA standards using Web of Science (WoS) and PubMed databases. Any kind of genes, proteins, and molecular molecules were included in this systematic review. The list of these immune-related molecules was analyzed in the STRING database for functional enrichment analysis. Results: We found that 17 research studies discussed immune-related molecules and 30 immune proteins. These studies showed that exercise had the ability to ameliorate dysfunction in AD-related pathways, which led to decreasing the expression of microglia-related pathways and Th17-related immune pathways. As a result of decreasing the expression of immune-related pathways, the expression of apoptosis-related pathways was also decreasing, and neuronal survival was increased by exercise activity. Conclusions: Based on functional enrichment analysis, exercise not only could reduce apoptotic factors and immune components but also could increase cell survival and Aß clearance in cortex samples. PROSPERO ID: CRD42022326093.

Tyrosine Metabolism Pathway Is Downregulated in Dopaminergic Neurons with LRRK2 Overexpression in Drosophila.

LRRK2 mutations are the leading cause of familial Parkinson's disease (PD) and are a significant risk factor for idiopathic PD cases. However, the molecular mechanisms underlying the degeneration of dopaminergic (DA) neurons in LRRK2 PD patients remain unclear. To determine the translatomic impact of LRRK2 expression in DA neurons, we employed gene set enrichment analysis (GSEA) to analyze a translating ribosome affinity purification (TRAP) RNA-seq dataset from a DA-neuron-specific-expressing Drosophila model. We found that the tyrosine metabolism pathway, including tyrosine hydroxylase (TH), is downregulated in DA neurons with LRRK2 overexpression; in contrast, the Hippo signaling pathway is downregulated in the G2019S mutant compared to wild-type LRRK2 in the DA neurons. These results imply that the downregulation of tyrosine metabolism occurs before pronounced DA neuron loss and that LRRK2 may downregulate the tyrosine metabolism in a DA-neuron-loss-independent way.

miRNA profiling as a complementary diagnostic tool for amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS), the most prevalent motor neuron disease characterized by its complex genetic structure, lacks a single diagnostic test capable of providing a conclusive diagnosis. In order to demonstrate the potential for genetic diagnosis and shed light on the pathogenic role of miRNAs in ALS, we developed an ALS diagnostic rule by training the model using 80% of a miRNA profiling dataset consisting of 253 ALS samples and 103 control samples. Subsequently, we validated the diagnostic rule using the remaining 20% of unseen samples. The diagnostic rule we developed includes miR-205-5p, miR-206, miR-376a-5p, miR-412-5p, miR-3927-3p, miR-4701-3p, miR-6763-5p, and miR-6801-3p. Remarkably, the rule achieved an 82% true positive rate and a 73% true negative rate when predicting the unseen samples. Furthermore, the identified miRNAs target 21 genes in the PI3K-Akt pathway and 27 genes in the ALS pathway, including notable genes such as BCL2, NEFH, and OPTN. We propose that miRNA profiling may serve as a complementary diagnostic tool to supplement the clinical presentation and aid in the early recognition of ALS.

Osthole Antagonizes Microglial Activation in an NRF2-Dependent Manner.

Microglia are neuroglia in the brain with an innate immune function and participate in the progress of neurodegenerative diseases. Osthole (OST) is a coumarin derivative extracted from Cnidium monnieri and bears a microglia-antagonizing ability. However, the underlying mechanism of the antagonism is not clear. The lipopolysaccharides-induced microglial BV2 cell line and amyloid-overexpressing fruit fly were used as models to study OST treatment. We found that OST treatment is sufficient to evoke NRF2 cascade under an LPS-induced inflammatory environment, and silencing NRF2 is sufficient to abolish the process. Moreover, we found that OST is sufficient to antagonize microglial activation in both LPS-induced BV2 cells and Aß-overexpressing fruit flies, and silencing NRF2 abolishes OST's antagonism. Furthermore, OST treatment rescued survival, climbing, and the learning ability of Aß-overexpressing fruit flies and relieved oxidative stress. In conclusion, we proved that OST antagonizes microglial activation induced by either LPS or Aß and that NRF2 is necessary for OST's antagonism.

Increased substance P-like immunoreactivities in parabrachial and amygdaloid nuclei in a rat model with masticatory myofascial pain.

This study explores the involvement of substance P (SP) in the parabrachial nucleus (PBN) and central amygdaloid nucleus (CeA) in the nociception-emotion link and of rats with masticatory myofascial pain (MMP) induced by chronic tetanic eccentric muscle contraction. A total of 18 rats were randomly and equally assigned for MMP (MMP group) and sham-MMP induction (sMMP group). MMP was induced by electrical-stimulated repetitive tetanic eccentric contraction of the masseter muscle for 14 consecutive days. Myofascial trigger points in the masseter muscle were identified by palpable taut bands, increased prevalence of endplate noise (EPN), focal hypoechoic nodules on ultrasound and restricted jaw opening. All animals were killed for morphological and SP immunohistochemical analyses. Chronic tetanic eccentric contraction induced significantly thicker masseter muscle confirmed by hypoechogenicity, increased prevalence and amplitudes of EPN, and limited jaw opening. Immunohistochemically, the SP-like positive neurons increased significantly in PBN and CeA of the MMP group. Our results suggested that MMP increases the SP protein levels in PBN and CeA, which play important roles in MMP-mediated chronic pain processing as well as MMP-related emotional processes.

Higher stroke incidence in the patients with pancreatic cancer: A nation-based cohort study in Taiwan.

No study has investigated the role of pancreatic cancer in the stroke risk using population data. We used claims data obtained from a universal health insurance program of Taiwan to evaluate the stroke risk in pancreatic cancer patients.From the catastrophic disease registry of the insurance, we identified 7479 patients with pancreatic malignancy without stroke history from 2000 to 2009. The comparison cohort consisted of 29,916 individuals identified from 1 million insured people without cancer and stroke history, matching with the cancer cohort by propensity score. We followed each selected individual until stroke was diagnosed or until being censored for death or withdrawal from insurance, or for a maximum of 3 follow-up years, or the end of 2011.The pancreatic cancer cohort had a 2.3-fold greater incident stroke than comparisons had (28.5 vs 12.3 per 1000 person-years), with an adjusted hazard ratio (aHR) of 2.74 (95% confidence interval (CI) = 2.31-3.24) after controlling for covariates, or a subdistribution hazard ratio (SHR) of 2.04 (95% CI = 1.74-2.40) accounting for the competing risk of deaths. During the follow-up period, stroke events occurred constantly in comparisons, but declined rapidly in the cancer cohort. The pancreatic cancer cohort had a stroke incidence of 46.6 per 1000 person-years within 6 months postdiagnosis, with an aHR of 4.37 (95% CI = 3.45-5.54) and a SHR of 3.87 (95% CI = 3.08-4.86), relative to comparisons.Our study suggests that patients with pancreatic cancer are at an elevated risk of stroke, patients deserve sufficient follow-up care, particularly in the first 6 months after the diagnosis of the cancer, and for those with comorbidities.

Cardiac Fas-Dependent and Mitochondria-Dependent Apoptotic Pathways in a Transgenic Mouse Model of Huntington's Disease.

Huntington's disease is an autosomal dominant neurodegenerative disease caused by a CAG repeat expansion in the huntingtin gene. Heart disease is the second leading cause of death in patients with Huntington's disease. This study was to evaluate whether cardiac Fas-dependent and mitochondria-dependent apoptotic pathways are activated in transgenic mice with Huntington's disease. Sixteen Huntington's disease transgenic mice (HD) and sixteen wild-type (WT) littermates were studied at 10.5 weeks of age. The cardiac characteristics, myocardial architecture, and two major apoptotic pathways in the excised left ventricle from mice were measured by histopathological analysis, Western blotting, and TUNEL assays. The whole heart weight and the left ventricular weight decreased significantly in the HD group, as compared to the WT group. Abnormal myocardial architecture, enlarged interstitial spaces, and more cardiac TUNEL-positive cells were observed in the HD group. The key components of Fas-dependent apoptosis (TNF-alpha, TNFR1, Fas ligand, Fas death receptors, FADD, activated caspase-8, and activated caspase-3) and the key components of mitochondria-dependent apoptosis (Bax, Bax-to-Bcl-2 ratio, cytosolic cytochrome c, activated caspase-9, and activated caspase-3) increased significantly in the hearts of the HD group. Cardiac Fas-dependent and mitochondria-dependent apoptotic pathways were activated in transgenic mice with Huntington's disease, which might provide one of possible mechanisms to explain why patients with Huntington's disease will develop heart failure.

Clonidine intensifies memantine cutaneous analgesia in response to local skin noxious pinprick in the rat.

BACKGROUND: The purposes of this study were to evaluate the co-administration of clonidine with memantine and to determine whether it has a peripheral action in intensifying cutaneous analgesia. METHODS: Cutaneous analgesia was examined through inhibition of the cutaneous trunci muscle reflex in response to the local noxious pinprick in rats. Effect of the added subcutaneous clonidine to memantine on infiltrative cutaneous analgesia was assessed and compared with the local anesthetic lidocaine. RESULTS: On the 50% effective dose (ED50) basis, the rank of drug potency was memantine [4.05 (3.95-4.18) µmol]>lidocaine [5.81 (5.70-5.98) µmol] (p<0.01). Clonidine at a dose of 0.12 µmol did not elicit cutaneous analgesia. Mixtures of clonidine (0.12 µmol) with drug (memantine or lidocaine) at ED50 or ED95 prolonged the duration of action and enhanced the potency as infiltrative cutaneous analgesia. Clonidine enhanced the lidocaine cutaneous analgesia in which had a better effect than added to memantine. CONCLUSIONS: Our resulting data showed that memantine displayed more potent cutaneous analgesia than lidocaine. Co-administration of memantine or lidocaine with clonidine increased the potency and duration of the cutaneous analgesia. Clonidine intensified the effects of lidocaine promoting cutaneous analgesia than added to memantine.

Proteomic analysis of urethral protein expression in an estrogen receptor α-deficient murine model of stress urinary incontinence.

PURPOSE: The roles of estrogen receptor α (ERα) in stress urinary incontinence (SUI) remain elusive. This study was conducted to understand the molecular mechanism of ERα against SUI. METHODS: Wild-type (ERα(+/+)) and ACTB-cre ERα knockout (ERα(-/-)) female mice were generated. Urethral function and protein expression were measured. Leak point pressures (LPP) and maximum urethral closure pressure (MUCP) were assessed in mice under urethane anesthesia. After the measurements, the urethras were removed for proteomic analysis using the two-dimensional differential gel electrophoresis and liquid chromatography-mass spectrometry technology. Interaction between these ERα pathway proteins was further analyzed by using MetaCore. Lastly, Western blot and immunochemistry (IHC) were used to confirm the candidate protein expression levels and locations, respectively. RESULTS: Compared with the ERα(+/+) group, the LPP and MUCP values of the ERα(-/-) group were significantly decreased. Additionally, we identified 11 differentially expressed proteins in the urethra of ERα(-/-) female mice; five proteins were down-regulated and six were up-regulated. The majority of the ERα knockout-modified proteins were involved in muscle development, contraction, and regulation, as well as immune response (amphoterin signaling and phagocytosis), proteolysis, and cell adhesion (platelet aggregation and integrin-mediated cell-matrix adhesion). IHC and Western blot confirmed the down-regulation of tropomyosin and up-regulation of myosin in urethra. CONCLUSIONS: This is the first study to estimate protein expression changes in urethras from ERα(-/-) female mice. These changes could be related to the molecular mechanism of ERα in SUI.

Urethral dysfunction in female mice with estrogen receptor ß deficiency.

Estrogen has various regulatory functions in the growth, development, and differentiation of the female urogenital system. This study investigated the roles of ERß in stress urinary incontinence (SUI). Wild-type (ERß(+/+)) and knockout (ERß(-/-)) female mice were generated (aged 6-8 weeks, n = 6) and urethral function and protein expression were measured. Leak point pressures (LPP) and maximum urethral closure pressure (MUCP) were assessed in mice under urethane anesthesia. After the measurements, the urethras were removed for proteomic analysis using label-free quantitative proteomics by nano-liquid chromatography-mass spectrometry (LC-MS/MS) analysis. The interaction between these proteins was further analysed using MetaCore. Lastly, Western blot was used to confirm the candidate proteins. Compared with the ERß(+/+) group, the LPP and MUCP values of the ERß(-/-) group were significantly decreased. Additionally, we identified 85 differentially expressed proteins in the urethra of ERß(-/-) female mice; 57 proteins were up-regulated and 28 were down-regulated. The majority of the ERß knockout-modified proteins were involved in cell-matrix adhesion, metabolism, immune response, signal transduction, nuclear receptor translational regelation, and muscle contraction and development. Western blot confirmed the up-regulation of myosin and collagen in urethra. By contrast, elastin was down-regulated in the ERß(-/-) mice. This study is the first study to estimate protein expression changes in urethras from ERß(-/-) female mice. These changes could be related to the molecular mechanism of ERß in SUI.

Association of glutathione S-transferase P1 (GSTP1) polymorphism with Tourette syndrome in Taiwanese patients.

The etiology of Tourette syndrome (TS) is multifactorial. TS vulnerability may be associated with genetic and environmental factors. From the genetic point of view, TS is heterogeneous. Previous studies showed that some single-nucleotide polymorphisms (SNPs) of the glutathione-S-transferase P1 (GSTP1) gene can affect cellular proliferation and apoptotic activity and TS is a neurodevelopmental disorder. We guessed that there was a relationship between TS and genetic variants of the GSTP1 gene. Therefore, in this study, we aimed to test the hypothesis that GSTP1 SNPs were associated with TS. We performed a case-control study. One hundred twenty-one TS children and 105 normal children were included in the study. Polymerase chain reaction was used to identify the GSTP1 gene polymorphism at position rs6591256 (A/G, promoter polymorphism) in TS patients and normal children. The polymorphism at position rs6591256 in the GSTP1 gene revealed significant differences in the allele (p=0.0135) and genotype (p=0.0159) distributions between the TS patients and the control group. The A allele was present at a higher frequency than the G allele in the TS patients compared with the control group (odds ratio [OR]=1.91, 95% confidence interval [CI]: 1.14-3.21). The AA genotype was associated with susceptibility to TS with an OR of 2.38 for the AA versus AG genotype (95% CI: 1.29-4.41). These findings suggest that variants in the GSTP1 gene may play a role in susceptibility to TS.

Association of tyrosyl-DNA phosphodiesterase 1 polymorphism with Tourette syndrome in Taiwanese patients.

BACKGROUND: Genetic, environmental, immunological, and hormonal factors contribute to the etiology of Tourette syndrome (TS). From the genetic standpoint, TS is a heterogeneous disorder. In our previous study, we found that a single nucleotide polymorphism (SNP) of x-ray repair cross-complementing group 1 (XRCC1), a DNA repair gene, was associated with TS. Previous studies also showed that tyrosyl-DNA phosphodiesterase 1 (TDP1) interacts with XRCC1 to repair damaged DNA. However, the relationship between TS and SNPs of TDP1 gene is unknown. Therefore, the aim of this study was to test the hypothesis that if the TDP1 SNP, rs28365054 (c.400G>A, Ala134Thr), was associated with TS or not. METHODS: A case-control study was designed to test the hypothesis. A total of 122 TS children and 106 normal children participated in the study. We used polymerase chain reaction to identify the SNP, rs28365054, of the TDP1 gene in the TS patients and the normal children. RESULTS: A polymorphism at position rs28365054 in the TDP1 gene had a significant difference (P < 0.05) in the genotype distributions between the TS patients and the control group. The AG genotype was a risk factor for TS with an odds ratio of 2.26 for the AG versus AA genotype (95% CI 1.08-4.72). CONCLUSION: The findings of this study suggested that variants in the TDP1 gene might play a role in TS susceptibility.

Association of poly(ADP-ribose) polymerase-1 polymorphism with Tourette syndrome.

Tourette syndrome (TS) is an etiologically heterogeneous disorder, the pathogenesis of which is incompletely understood. Poly(ADP-ribose) polymerase 1 (PARP1) is involved in regulation of developmental processes and cellular differentiation, in transcription regulation, in DNA repair, and in cell death. However, the relationship between TS and single nucleotide polymorphisms (SNPs) of PARP1 is unknown. Therefore, the aim of this experiment was to test the hypothesis that whether the PARP1 SNP, rs1805404 (c.243C>T, Asp81Asp), had an association with TS. A case-control experiment was designed to test this hypothesis. 123 TS children and 122 normal children were enrolled in this study. Polymerase chain reaction restriction fragment length polymorphism was used for the detection of the PARP1 SNP, rs1805404, in TS patients and normal children. The data showed that there is a significant difference in genotype distributions between these two groups. The CT genotype was a risk factor for TS with an odds ratio of 2.34 for the CT versus TT genotype (95% CI 1.16-4.74). The data also showed this SNP had an association with TS under recessive model (P = 0.0426), and TT genotype had a protective effect against TS with an odds ratio of 0.50 (95% CI 0.26-0.98). The findings of this study suggested that variants in the PARP1 gene might play a role in susceptibility to TS.

Ginkgo biloba extract attenuates oxLDL-induced endothelial dysfunction via an AMPK-dependent mechanism.

Atherosclerosis is a complex inflammatory arterial disease, and oxidized low-density lipoprotein (oxLDL) is directly associated with chronic vascular inflammation. Previous studies have shown that Ginkgo biloba extract (GbE) acts as a therapeutic agent for neurological and cardiovascular disorders. However, the mechanisms mediating the actions of GbE are still largely unknown. In the present study, we tested the hypothesis that GbE protects against oxLDL-induced endothelial dysfunction via an AMP-activated protein kinase (AMPK)-dependent mechanism. Human umbilical vein endothelial cells were treated with GbE, followed by oxLDL, for indicated time periods. Results from Western blot showed that GbE inhibited the membrane translocation of the NADPH oxidase subunits p47(phox) and Rac-1 and attenuated the increase in protein expression of membrane subunits gp91 and p22(phox) caused by oxLDL-induced AMPK dephosphorylation and subsequent PKC activation. AMPK-α(1)-specific small interfering RNA-transfected cells that had been exposed to GbE followed by oxLDL revealed elevated levels of PKC and p47(phox). In addition, exposure to oxLDL resulted in reduced AMPK-mediated Akt/endothelial nitric oxide (NO) synthase signaling and the induction of phosphorylation of p38 mitogen-activated protein kinase, which, in turn, activated NF-κB-mediated inflammatory responses, such as the release of interleukin-8, the expression of the adhesion molecule, and the adherence of monocytic cells to human umbilical vein endothelial cells. Furthermore, oxLDL upregulated the expression of inducible NO synthase, thereby augmenting the formation of NO and protein nitrosylation. Pretreatment with GbE, however, exerted significant cytoprotective effects in a dose-dependent manner. Results from this study may provide insight into a possible molecular mechanism by which GbE protects against oxLDL-induced endothelial dysfunction.

Altered nitroxidergic and NMDA receptor-mediated modulation of baroreflex-mediated heart rate in obese Zucker rats.

Arterial baroreflex, an important physiological regulatory system for buffering systemic blood pressure, is impaired in obesity. This study investigated whether the blunted baroreflex function in obesity is attributed to the altered nitroxidergic or N-methyl--aspartate (NMDA) mechanism. Baroreflex bradycardia responses, blood pressure and heart rate in 30 lean and 30 obese anesthetized Zucker rats (8-12 weeks of age) were assessed after injecting phenylephrine with intravenous preadministration of saline (control), dextromethorphan (DXM, NMDA receptor antagonist, 10 mg kg(-1)) or N(G)-nitro-L-arginine methyl ester (L-NAME, nitric oxide synthase inhibitor, 100 mg kg(-1)). Compared with lean rats (-2.00+/-0.29 b.p.m. mm Hg(-1)), the baroreflex sensitivity (BRS) in obese rats (-0.43+/-0.05 b.p.m. mm Hg(-1)) was significantly blunted. The BRS was significantly suppressed by DXM in lean rats but not in obese rats. After administration of L-NAME, BRS was significantly suppressed in lean Zucker rats but not in obese Zucker rats. The normal BRS was significantly suppressed in lean rats after administration of both DXM and L-NAME, and the blunted BRS in obesity was significantly blocked to nearly no BRS after administration of both DXM and L-NAME. This study suggests that BRS is blunted in obese rats and that blunted baroreflex is, at least in part, attributed to altered nitroxidergic or NMDA receptor-mediated modulation.

Evaluation of the poly(ADP-ribose) polymerase-1 gene variants in Alzheimer's disease.

Amyloid peptide is thought to play a critical role in neuronal death in Alzheimer's disease (AD), most likely through oxidative stress. Free radical-related injury leads to DNA breaks, which subsequently activates the repair enzyme poly(ADP-ribose) polymerase-1 (PARP-1). In this study, the relationship between genetic variants situated at the PARP-1 gene and AD development was investigated. We performed a case and control study from a Taiwanese population enrolled 120 AD patients and 111 healthy controls by using a polymerase chain reaction restriction fragment length polymorphism approach for two PARP-1 exonic polymorphisms, 414C/T (rs1805404) and 2456T/C (rs1136410), corresponding to protein residues at positions 81Asp/Asp and 762Val/Ala. There were no significant differences in allele or genotype frequencies for either PARP-1 gene variant between the case and control groups; however, upon analysis of the haplotype distribution, four haplotypes (Hts) were identified. We found that the distributions of Ht3-TT and Ht4-CC were significantly associated with an increased risk of AD (P<0.0001), whereas the Ht1-TC haplotype showed a protective effect for cases compared with the control group (P<0.05). These results reveal that the PARP-1 gene is highly associated with AD susceptibility and might contribute to a critical mechanism that mediates cell survival or death as a response to cytotoxic stress.

Diphenidol inhibited sodium currents and produced spinal anesthesia.

The aim of this study was to evaluate the effect of diphenidol on blocking Na(+) currents and spinal anesthesia. We used the patch-clamp method to examine if diphenidol blocked Na(+) currents. Lidocaine, a common used local anesthesia, was used as control. We also evaluated the potencies and durations of diphenidol and lidocaine on spinal blockades of motor function, proprioception, and nociception in rats. Lidocaine exhibited a concentration- and state-dependent effect on tonic blockade of voltage-gated Na(+) currents in mouse neuroblastoma N2A cells (IC(50) of 8.1 and 138.9 microM at holding potentials of -70 and -100 mV, respectively). Diphenidol was more potent (IC(50) of 0.77 and 62.6 microM at holding potentials of -70 and -100 mV, respectively). However, unlike lidocaine, block of Na(+) currents by diphenidol lacked use-dependence. We also found that diphenidol acted like lidocaine and produced dose-related spinal blockades of motor function, proprioception and nociception. Although diphenidol had similar potencies of spinal anesthesia compared with lidocaine it produced a much longer duration of spinal blockades than lidocaine. Our results demonstrated that intrathecal diphenidol produced a long duration and similar potency on spinal anesthesia compared with lidocaine in rats. The anesthetic effect of diphenidol could be in part due to its blockade of Na(+) currents.

Genetic variation in N-methyl-D-aspartate receptor subunit NR3A but not NR3B influences susceptibility to Alzheimer's disease.

BACKGROUND: The administration of memantine, an N-methyl-D-aspartate (NMDA) receptor antagonist, has clinically improved the cognitive function of patients with Alzheimer's disease (AD), indicating that a disturbance in glutamatergic transmission might be involved in a predisposition to developing the disease. AIM: The potential association of polymorphisms in NMDA receptor subunits NR3A and NR3B, encoded by the GRIN3A and GRIN3B genes, with AD was investigated. METHODS: We performed a case-control study. Two single nucleotide polymorphisms, 3104 G/A (rs10989563) and 3723 G/A (rs3739722), in the GRIN3A gene and 2 GRIN3B gene polymorphisms, 1210 C/T (rs4807399) and 1730 C/T (rs2240158), were studied. RESULTS: Upon genotyping of the exonic polymorphism in the GRIN3A gene, the G allele was present at a higher rate than the A allele at position 3723 in AD patients compared with normal groups (p < 0.05). Three haplotypes (designated Ht1-3) were identified from these 2 polymorphisms (3104 G/A and 3723 G/A), and the distribution of Ht2 (AG) differed between AD patients and controls (p < 0.05). Additionally, from the 2 GRIN3B gene variants 1210 C/T and 1730 C/T analyzed, no strong association with AD was observed. CONCLUSION: These observations suggest that the genetic variation of the NR3A, but not NR3B, subunit of the NMDA receptor may be a risk factor for AD pathogenesis among the Taiwanese population.

HMJ-53A accelerates slow inactivation gating of voltage-gated K+ channels in mouse neuroblastoma N2A cells.

Voltage-gated K(+) (Kv) channels are important in repolarization of excitable cells such as neurons and endocrine cells. Kv channel gating exhibits slow inactivation (slow current decay) during continuous depolarization. The molecular mechanism involved in such slow inactivation is not completely understood, but evidence has suggested that it involves a restriction of the outer channel pore surrounding the selectivity filter. Pharmacological tools probing this slow inactivation process are scarce. In this work we reported that bath application of HMJ-53A (30 microM), a novel compound, could drastically speed up the slow decay (decay tau=1677+/-120 ms and 85.6+/-7.7 ms, respectively, in the absence and presence of HMJ-53A) of Kv currents in neuroblastoma N2A cells. HMJ-53A also significantly left-shifted the steady-state inactivation curve by 12 mV. HMJ-53A, however, did not affect voltage-dependence of activation and the kinetics of channel activation. Intracellular application of this drug through patch pipette dialysis was ineffective at all in accelerating the slow current decay, suggesting that HMJ-53A acted extracellularly. Blockade of currents by HMJ-53A did not require an open state of channels. In addition, the inactivation time constants and percentage block of Kv currents in the presence of HMJ-53A were independent of the (i) degree of depolarization and (ii) intracellular K(+) concentration. Therefore, this drug did not appear to directly occlude the outer channel pore during stimulation (depolarization). Taken together, our results suggest that HMJ-53A selectively affected (accelerated) the slow inactivation gating process of Kv channels, and could thus be a selective and novel probe for the inactivation gate.