A novel DISC1-interacting partner DISC1-Binding Zinc-finger protein: implication in the modulation of DISC1-dependent neurite outgrowth

Disrupted-in-schizophrenia 1 (DISC1) is a gene disrupted by a (1;11) (q42.1;q14.3) translocation that segregates with major psychiatric disorders in a Scottish family. To investigate how DISC1 confers susceptibility to psychiatric disorders, we previously identified fasciculation and elongation protein zeta-1 and Kendrin as DISC1-interacting molecules in a yeast two-hybrid screen of a human brain complementary DNA library. Here, we have further identified a novel DISC1-interacting protein, termed DISC1-Binding Zinc-finger protein (DBZ), which has a predicted C(2)H(2)-type zinc-finger motif and coiled-coil domains. DBZ was co-immunoprecipitated with DISC1 in lysates of PC12 cells and rat brain tissue. The domain of DISC1 interacting with DBZ was close to the translocation breakpoint in the DISC1 gene. DBZ messenger RNA (mRNA) was expressed in human brains, but not in peripheral tissues. In situ hybridization revealed high expression of DBZ mRNA in the hippocampus, olfactory tubercle, cerebral cortex and striatum in rats. Because this pattern of localization was similar to that of the pituitary adenylate cyclase (PAC(1)) receptor for pituitary adenylate cyclase-activating polypeptide (PACAP), which has recently been implicated in neuropsychological functions, we examined whether DISC1/DBZ interaction was involved in the PACAP signaling pathway. PACAP upregulated DISC1 expression and markedly reduced the association between DISC1 and DBZ in PC12 cells. A DISC1-binding domain of DBZ reduced the neurite length in PC12 cells after PACAP stimulation and in primary cultured hippocampal neurons. The present results provide some new molecular insights into the mechanisms of neuronal development and neuropsychiatric disorders.

Novel mutation of the Notch3 gene in a Japanese patient with CADASIL

We report a novel missense mutation of the Notch3 gene in a Japanese family with CADASIL. The Cys49Gly mutation in this family is located in exon 2 of the Notch3 gene. Most of the documented Notch3 gene mutations occur in exons 3 or 4. On the other hand, there are few reports around the world of mutations in exon 2 of the Notch3 gene, and this is the first report of a mutation in exon 2 of the gene in a Japanese family. In general, CADASIL mutations involve a cysteine residue. Such mutations may influence the tertiary structure of the Notch3 protein, resulting in protein dysfunction. Thus, the CADASIL in the present case may be a consequence of the mutation in exon 2 causing a structural change in the Notch3 protein.

Effect of late evening snack with rice ball on energy metabolism in liver cirrhosis

OBJECTIVE

This study investigates the effects of a late evening snack (LES), of 200 kcal of rice ball, on energy metabolism in cirrhotic patients. Impaired nutritional metabolism has been associated with cirrhosis, and frequent intake of small meals may prevent early-onset starvation, and maintain nourishment in these patients.

SUBJECTS

Twenty-one cirrhotic patients and 26 control subjects (Control) were recruited for this study. Patients were subsequently treated by LES (LC-LES) and by a non-LES regimen (LC-NLES).

METHOD

Resting energy expenditure and respiratory quotient (RQ) were assessed by indirect calorimetry at 0830, 1130 and 1430. Blood glucose and non-esterified fatty acids (NEFA) were measured just before the energy metabolism measurements. The regular diet included three major meals and LES, at 0900, 1200, 1800 and 2100, respectively. The Control and LC-NLES groups received only the major meals, whereas the LC-LES group received three meals plus 200 kcal LES for 7 days. There was no difference in the total energy intake among Control, LC-NLES and LC-LES groups.

RESULTS

Respiratory quotient in LC-NLES was significantly lower than that of Control at 0830. Respiratory quotient value in LC-LES significantly elevated from that in LC-NLES. The RQ values did not differ among Control, LC-NLES and LC-LES at 2 h after the meal (1130 and 1430). Non-esterified fatty acids in LC-LES were lower than that in LC-NLES after overnight fasting.

CONCLUSIONS

The ingestion of a 200 kcal rice ball LES can improve the nutritional metabolism in cirrhotic patients.

Brain Cytokines and Chemokines: Roles in Ischemic Injury and Pain

Cytokines and chemokines were originally identified as essential mediators for inflammatory and immune responses. Enhanced production and release of cytokines/chemokines are observed also in the central nervous system (CNS) under diverse pathological conditions. There is growing evidence showing that brain cytokines/chemokines play crucial roles in the neuro-glio-vascular interaction underlying the pathology of various brain disorders and therefore are potential targets for development of novel and effective therapeutics for CNS diseases. Here the evidence of the involvement of cytokines/chemokines in ischemic brain injury and pain is reviewed.

CD2+ acute promyelocytic leukemia is associated with leukocytosis, variant morphology and poorer prognosis

The T cell-lineage marker CD2 is sometimes expressed in acute promyelocytic leukemia (APL), and CD2 expression is reported to correlate with some clinical characteristics. However, the significance of CD2 expression in APL has not been fully elucidated. We evaluated CD2 expression in APL treated by the same treatment strategy in a single institute, and whether it had any special characteristics. Among 29 APL, 6 were positive for CD2. Patients with CD2+ APL tended to have a higher leukocyte count than CD2- APL (34.5 +/- 13.1/l vs. 6.8 +/- 2.1/l), morphological characteristics as variant-APL (50 vs. 0%). They also showed poor clinical prognosis. The CR rate of CD2- APL was 87.0% while that of CD2+ APL was 50 %. The mortality was 13.0 and 66.7%, respectively, and the survival rate was significantly lower in CD2+ APL. CD2 expression was proven to be a risk factor associated with death in addition to the morphological characteristics of variant-APL and leukocytosis. These results indicated that CD2 expression might have a significant impact on the prognosis of APL. Whether CD2+ APL should be characterized as a special clinical entity should be discussed in a larger patient population.

GRP94 reduces cell death in SH-SY5Y cells perturbated calcium homeostasis

The endoplasmic reticulum (ER) resident-94 kDa glucose-regulated protein (GRP94), plays a pivotal role in cell death due to ER stress. In our study expression of GRP94 was increased in human neuroblastoma SH-SY5Y cells due to exposure to calcium ionophore A23187. A23187-mediated cell death was associated with activation of the major cysteine proteases, caspase-3 and calpain. Pretreatment with adenovirus-mediated antisense GRP94 (AdGRP94AS) reduced viability of SH-SY5Y cells subjected to A23187 treatment compared with wild type cells or cells with adenovirus-mediated overexpression of GRP94 (AdGRP94S). These results indicated that suppression of GRP94 is associated with accelerated cell death. Moreover, expression of GRP94 suppressed A23187-induced cell death and stabilized calcium homeostasis.

Radiation-heat synergism for inactivation of Alicyclobacillus acidoterrestris spores in citrus juice

The objective of this study was to investigate the influence of electron-beam and gamma-ray irradiation and temperature (85 to 95 degrees C) on Alicyclobacillus acidoterrestris GD3B strain (NCIMB 13137) spores by calculating and comparing the decimal reduction dose or time (D-values). The survival rate of A. acidoterrestris spores decreased exponentially with irradiation doses of an electron beam or gamma ray. D-values determined for electron-beam and gamma-ray irradiated spores on filter paper ranged from 1.02 to 1.10 kGy. On the other hand, the thermal sterilization effect showed a single exponential decrease within 1.5-log decreases in cell numbers (D85 degrees C = 70.5 min, D90 degrees C = 16.1 min, and D95 degrees C = 5.19 min and z-value [change in temperature required to change the D-value] was 8.83 degrees C), and prolonged heating produced an increase of 10 to 13 times that of the thermal resistance. However, within all time ranges studied (5 to 360 min), a linear decrease in the D-value was observed with an increase in the temperature. A combination of two different methods, irradiation before heating, was appropriate for reducing the duration of the heat treatment required to achieve the inactivation of conidia. Moreover, a necessary radiation dosage for complete inactivation of A. acidoterrestris spores that contaminated dextrin was examined. Dextrin is often used in the juice industry as an augmentor, and it is known to be sometimes contaminated by these spores. The D-values of the spores in dextrin for electron-beam and gamma-ray irradiations were 1.72 and 1.79 kGy, respectively. The doses required for elimination of the spores could be lowered by using irradiation in combination with heat sterilization. When dextrin powder contaminated with 10(4) CFU/g of A. acidoterrestris was preirradiated at 1.0 kGy of electron beam, the citrus juice containing dextrin at a concentration of 10% (wt/vol) was completely sterilized by heating for 20 min at 95 degrees C.

A new form of retinopathy associated with myocardial infarction treated with percutaneous coronary intervention

AIM

To report a new form of retinopathy that was observed in patients who had undergone percutaneous coronary intervention (PCI) following acute myocardial infarction (AMI).

METHODS

Serial ophthalmological examinations were conducted in 40 patients who underwent PCI. Thirty patients were diagnosed with AMI, and another 10 had stable angina pectoris.

RESULTS

Cotton wool spots developed in 17 (57%) patients from the group with AMI undergoing PCI (n = 30) within 2 months. Of these, 41% (seven patients) also developed superficial haemorrhages. Retinopathy was most prominent 1-2 months after AMI and then tended to become quiescent afterwards, without treatment.

CONCLUSION

We have identified a new form of retinopathy in patients with AMI that spontaneously subsides without treatment.

Brain protection by resveratrol and fenofibrate against stroke requires peroxisome proliferator-activated receptor alpha in mice

Peroxisome proliferator-activated receptors (PPARs) are ligand-dependent transcription factors which belong to the nuclear receptor family. We examined whether PPARalpha agonists and resveratrol, a polyphenol contained in grapes, protect the brain against ischemia. To investigate whether resveratrol activates PPARs, we performed a cell-based transfection activity assay using luciferase reporter plasmid. PPARalpha and PPARgamma were activated by resveratrol in primary cortical cultures and vascular endothelial cells. Resveratrol (20 mg/kg, 3 days) reduced infarct volume by 36% at 24 h after middle cerebral artery occlusion in wild-type mice. The PPARalpha agonists fenofibrate (30 mg/kg, 3 days) and Wy-14643 (30 mg/kg, days) exerted similar brain protection. However, resveratrol and fenofibrate failed to protect the brain in PPARalpha knockout mice. The data indicate that PPARalpha agonists protect the brain through PPARalpha.

Mesangial cell apoptosis induced by a fibronectin fragment

We previously showed that in passive Heymann nephritis (PHN) rats, a large quantity of fibronectin (FN) fragments containing the central cell-binding (CCB) domain and adjacent domains are generated in the kidney and excreted into urine (Nishizawa et al., Biol Pharm Bull 1998; 21: 429-433). To ascertain whether the FN fragments could affect the progression of PHN, we investigated the effect of a 150 K FN fragment containing the CCB and carboxyl-terminal heparin-binding (Hep 2) domains on cultured rat mesangial cells. When rat mesangial cells cultured on FN-coated plates were exposed to the 150 K FN fragment, some mesangial cells detached from the FN substrate and then underwent apoptosis as judged by nuclear and DNA fragmentations. The 150 K FN fragment competitively inhibited the mesangial cell adhesion to the FN substrate in a dose-dependent manner. Furthermore, gelatinzymography of the conditioned medium of mesangial cells showed that the 150 K FN fragment induced and/or potentiated the extracellular matrix (ECM)-degrading proteinases including matrix metalloproteinases (MMPs) of mesangial cells. These results indicate that the 150 K FN fragment may elicit mesangial cell apoptosis by disrupting the mesangial cell adhesion through two distinct ways: the inhibition of mesangial cell adhesion and the ECM-degradation by the 150 K FN fragment-induced MMPs. Thus, FN fragments containing the CCB and adjacent domains generated in the kidneys of PHN rats may be involved in the evolution of the renal injury.

Identification of the region in Escherichia coli DnaA protein required for specific recognition of the DnaA box

DnaA protein binds specifically to a 9-base- pair motif called the DnaA box. Domain IV comprises 94 amino acid residues and is required for DNA binding. Using nuclear magnetic resonance analysis, we investigated the interaction between DnaA domain IV and both a DnaA box and a non-specific oligonucleotide that has a reduced affinity for DnaA. The 1H-15N HSQC spectrum of DnaA domain IV showed prominent chemical shift perturbations on six residues (Arg399, Ala404, Leu422, Asp433, Thr435 and Thr436) in the presence of the DnaA box. Through homology modeling, we located all of these residues on one side surface of the DnaA domain IV molecule. Moreover, we compared the chemical shift perturbation of the 1H-15N HSQC spectrum in the presence of the DnaA box with that in the presence of a non-specific oligonucleotide, and the results suggested that Leu422 imparts specificity in binding with the DnaA box.

Effect of milrinone on vecuronium-induced neuromuscular block

We examined the effect of milrinone, a phosphodiesterase III inhibitor, on neuromuscular block induced by vecuronium. Thirty adult patients were randomly assigned to one of two equal groups: the milrinone group and the control group. Subjects in the milrinone group received an intravenous loading dose of milrinone 5 microg x kg-1x min-1 for 10 min, followed by an infusion at a rate of 0.5 microg x kg-1x min-1. Subjects in the control group received normal saline at a rate of 0.1 ml x kg-1 x h-1. Thirty minutes after the beginning of the infusion of milrinone, anaesthesia was induced with intravenous thiopental 4 mg x kg-1 and fentanyl 2 microg x kg-1, and was maintained with isoflurane in oxygen and nitrous oxide. Neuromuscular blockade was monitored electromyographically at the adductor pollicis muscle. The times from the administration of vecuronium 0.1 mg.kg-1 to the onset of neuromuscular block and the return of the first, second, third, and fourth response of the train-of-four were compared between the two groups. Times to the recovery of the ratio of the first twitch to the control twitch to 25%, 50% and 75%, and times to the recovery of train-of-four ratio to 25%, 50% and 75% were also compared between the two groups. The onset of neuromuscular block in the milrinone group was significantly slower than in the control group. The times to the returns of the four twitches of the train-of-four, times to recovery of the ratio of the first twitch to the control twitch to 25% and 50%, and the times to the recovery of the train-of-four ratio to 25% and 50% were significantly shorter in the milrinone group than in the control group. We conclude that milrinone delays the onset of neuromuscular blockade but hastens its recovery in anaesthetised patients receiving vecuronium.

Disrupted-In-Schizophrenia 1, a candidate gene for schizophrenia, participates in neurite outgrowth

Disrupted-In-Schizophrenia 1 (DISC1) was identified as a novel gene disrupted by a (1;11)(q42.1;q14.3) translocation that segregated with schizophrenia in a Scottish family. Predicted DISC1 product has no significant homology to other known proteins. Here, we demonstrated the existence of DISC1 protein and identified fasciculation and elongation protein zeta-1 (FEZ1) as an interacting partner of DISC1 by a yeast two-hybrid study. FEZ1 and its nematode homolog are reported to represent a new protein family involved in axonal outgrowth and fasciculation. In cultured hippocampal neurons, DISC1 and FEZ1 colocalized in growth cones. Interactions of these proteins were associated with F-actin. In the course of neuronal differentiation of PC12 cells, upregulation of DISC1/FEZ1 interaction was observed as along with enhanced extension of neurites by overexpression of DISC1. The present study shows that DISC1 participates in neurite outgrowth through its interaction with FEZ1. Recent studies have provided reliable evidence that schizophrenia is a neurodevelopmental disorder. As there is a high level of DISC1 expression in developing rat brain, dysfunction of DISC1 may confer susceptibility to psychiatric illnesses through abnormal development of the nervous system.

Induced HMGA1a expression causes aberrant splicing of Presenilin-2 pre-mRNA in sporadic Alzheimer's disease

The aberrant splicing isoform (PS2V), generated by exon 5 skipping of the Presenilin-2 (PS2) gene transcript, is a diagnostic feature of sporadic Alzheimer's disease (AD). We found PS2V is hypoxia-inducible in human neuroblastoma SK-N-SH cells. We purified a responsible trans-acting factor based on its binding to an exon 5 fragment. The factor was identified as the high mobility group A1a protein (HMGA1a; formerly HMG-I). HMGA1a bound to a specific sequence on exon 5, located upstream of the 5' splice site. HMGA1a expression was induced by hypoxia and the protein was accumulated in the nuclear speckles with the endogenous splicing factor SC35. Overexpression of HMGA1a generated PS2V, but PS2V was repressed by cotransfection with the U1 snRNP 70K protein that has a strong affinity to HMGA1a. HMGA1a could interfere with U1 snRNP binding to the 5' splice site and caused exon 5 skipping. HMGA1a levels were significantly increased in the brain tissue from sporadic AD patients. We propose a novel mechanism of sporadic AD that involves HMGA1a-induced aberrant splicing of PS2 pre-mRNA in the absence of any mutations.

Clinical significance of normalization of uterine artery pulsatility index with maternal heart rate for the evaluation of uterine circulation in pregnancy-induced hypertension

OBJECTIVE

To investigate whether the use of normalized pulsatility index (PI) improves evaluation of the fetal prognosis in pregnancy-induced hypertension (PIH).

METHOD

Eighty women with uncomplicated pregnancies and 46 women with PIH (33 with pre-eclampsia and 13 with gestational hypertension) were included in the study. Uterine artery PI and normalized PI were analyzed in relation to two neonatal parameters: incidence of small-for-gestational age infants and incidence of Cesarean section for non-reassuring fetal status.

RESULTS

In normal pregnancy, the normalized uterine artery PIs (mean +/- SD) at 25, 31, and 39 weeks of gestation were 0.70 +/- 0.15, 0.71 +/- 0.16, and 0.65 +/- 0.13, respectively. Using non-normalized PI, 10 of 46 PIH cases had increased PI; however, with normalization, two pre-eclampsia cases were added to the group with elevated PI, giving a total of 12. The incidences of small-for-gestational age infants and Cesarean section due to non-reassuring fetal status were higher in the elevated normalized uterine artery PI group. The use of normalized PI appeared to reduce the false-negative results in pre-eclampsia and PIH. After normalization, sensitivity, positive predictive value and negative predictive value of PI for small-for-gestational age infants and Cesarean section due to non-reassuring fetal status were improved in cases with pre-eclampsia and PIH. The incidence of these complications was low in gestational hypertension.

CONCLUSIONS

Normalization of the PI may improve predictive values for small-for-gestational age infants and delivery by cesarean section due to non-reassuring fetal status in PIH.

Kainic acid induces leukemia inhibitory factor mRNA expression in the rat brain: differences in the time course of mRNA expression between the dentate gyrus and hippocampal CA1/CA3 subfields

Leukemia inhibitory factor (LIF) is a pluripotent cytokine which affects the survival and differentiation of various types of cells both in the hematopoietic and nervous systems. In this study, the time course and localization of LIF mRNA expression following kainic acid-induced seizures were examined by northern blot analyses and in situ hybridization. Northern blot analyses demonstrated that intraperitoneal injection of kainic acid at a convulsive dose induced LIF mRNA expression intensely in the hippocampus and moderately to weakly in the cerebral cortex, thalamus and hypothalamus. The expression peaked at 8-24 h after the injection in the hippocampus and cerebral cortex and at 8 h in the thalamus and hypothalamus. In situ hybridization revealed different time courses of LIF mRNA expression depending on the area of the hippocampus; that is, the expression peaked at 10 h in the granule cell layer of the dentate gyrus, then at 12 h in the polymorph and molecular layers of the dentate gyrus, and finally at 12-24 h in the strata oriens and radiatum of the CA1 and CA3 subfields. It is worth noting that the expression of LIF mRNA was intense in the dentate gyrus, the region where neurogenesis and aberrant network reorganization have been shown to be induced by seizures. The upregulation of LIF mRNA expression in the dentate granule cell layer followed by that in the dentate polymorph and molecular layers may be involved in activity-dependent neurogenesis in the granule cell layer and ectopic migration of granule cells to the polymorph and molecular layers in the dentate gyrus.

Identification of the homolog of cell-counting factor in the cellular slime mold Dictyostelium discoideum

Genes for the cell-counting factors in Dictyostelium discoideum, countin and countin2, are considered to control the size of the multicellular structure of this organism. A novel gene, countin3, that is homologous to countin and countin2 genes (49 and 39% identity in amino acid sequence, respectively) was identified in the D. discoideum genome. The expression of countin3 was observed in the vegetatively growing cells, decreased in the aggregating stage, increased in the mid-developmental stage and decreased again in subsequent stages. This expression pattern is different from that of countin and countin2. The distinct expression kinetics of three genes suggests that they would have unique roles in size control of D. discoideum.

Excitotoxic injury induces production of monocyte chemoattractant protein-1 in rat cortico-striatal slice cultures

The effect of excitotoxic injury on the production of monocyte chemoattractant protein-1 (MCP-1) was examined in rat cortico-striatal slice cultures. Treatment with 50 microM N-methyl-D-aspartate (NMDA) for 4 h, which caused severe damage in neurons, induced the production of MCP-1 in astrocytes. Production levels were markedly elevated immediately after the treatment, peaked at 4-8 h, and had decreased to nearly the basal level by 72 h. Since the treatment promoted the release of MCP-1 in the slice cultures, but not in the enriched astrocyte cultures, it is unlikely that NMDA directly acted on the astrocytes. These results suggest that information on neuronal injury induced by NMDA is transmitted to astrocytes to induce the production of MCP-1. Organotypic slice cultures are useful for investigating the inflammatory responses of astrocytes in the process of neuronal injury.

ATP induces leukemia inhibitory factor mRNA in cultured rat astrocytes

Leukemia inhibitory factor (LIF) is a cytokine involved in the survival and differentiation of the neural cells in the central and peripheral nervous systems. In the present study, we examined the effects of various neurotransmitter receptor agonists on LIF mRNA expression in cultured rat astrocytes, microglia and neurons to elucidate the cell types producing LIF and to clarify the neurotransmitter(s) regulating the mRNA expression. The results demonstrated that the expression of LIF mRNA was intensely induced by ATP in the cultured astrocytes. Experiments using ATP, UTP and related compounds showed the involvement of P2Y2 and P2Y4 purinoceptors in the expression induced by ATP.

TAK-779, a nonpeptide CC chemokine receptor antagonist, protects the brain against focal cerebral ischemia in mice

The effect of a nonpeptide CC chemokine receptor antagonist, TAK-779, on ischemic brain injury resulting from 1-hour middle cerebral artery occlusion followed by 48-hour reperfusion was examined in ddY mice. On intracerebroventricular injection of vehicle or TAK-779, infarct volume in the vehicle-treated group was 44.2 +/- 13.2% of the contralateral hemispheric volume, and TAK-779 (25 and 250 ng/mouse) dose-dependently reduced the infarct volume to 35.0 +/- 12.2% and 31.1 +/- 12.9%, respectively. On intravenous injection, infarct volume in the vehicle-treated group was 32.0 +/- 16.1%, and TAK-779 (5 microg per 20 g body weight) significantly reduced this to 22.0 +/- 10.5%. The results showed for the first time that a nonpeptide chemokine receptor antagonist is protective against ischemic brain injury.