Prolyl-isomerase Pin1 accumulates in lewy bodies of parkinson disease and facilitates formation of alpha-synuclein inclusions

Parkinson disease (PD) is a relatively common neurodegenerative disorder that is characterized by the loss of dopaminergic neurons and by the formation of Lewy bodies (LBs), which are cytoplasmic inclusions containing aggregates of alpha-synuclein. Although certain post-translational modifications of alpha-synuclein and its related proteins are implicated in the genesis of LBs, the specific molecular mechanisms that both regulate these processes and initiate subsequent inclusion body formation are not yet well understood. We demonstrate in our current study, however, that the prolyl-isomerase Pin1 localizes to the LBs in PD brain tissue and thereby enhances the formation of alpha-synuclein immunoreactive inclusions. Immunohistochemical analysis of brain tissue from PD patients revealed that Pin1 localizes to 50-60% of the LBs that show an intense halo pattern resembling that of alpha-synuclein. By utilizing a cellular model of alpha-synuclein aggregation, we also demonstrate that, whereas Pin1 overexpression facilitates the formation of alpha-synuclein inclusions, dominant-negative Pin1 expression significantly suppresses this process. Consistent with these observations, Pin1 overexpression enhances the protein half-life and insolubility of alpha-synuclein. Finally, we show that Pin1 binds synphilin-1, an alpha-synuclein partner, via its Ser-211-Pro and Ser-215-Pro motifs, and enhances its interaction with alpha-synuclein, thus likely facilitating the formation of alpha-synuclein inclusions. These results indicate that Pin1-mediated prolyl-isomerization plays a pivotal role in a post-translational modification pathway for alpha-synuclein aggregation and in the resultant Lewy body formations in PD.

A case of novel de novo paired box gene 6 (PAX6) mutation with early-onset diabetes mellitus and aniridia

BACKGROUND

Paired box gene 6 (PAX6) is a transcription factor involved in eye development. Mutations of PAX6 cause congenital eye anomalies, such as aniridia. PAX6 is also involved in the development of the endocrine pancreas, and reported to be a genetic factor common to aniridia and glucose intolerance, although the latter is usually mild. Here, we describe a case of PAX6 mutation with early-onset diabetes mellitus.

CASE REPORT

A 27-year-old woman was referred to our clinic. She was diagnosed having diabetes at the age of 15 with negative glutamic acid decarboxylase (GAD) antibody. Insulin treatment was started at age 24. Because she had aniridia, PAX6 gene mutation was investigated and a heterozygous 2-bp deletion (c.402del2) was identified. Her parents did not have aniridia and PAX6 mutations. Heterozygous PAX6 mutation may cause glucose intolerance. However, cases of early-onset diabetes mellitus have not been reported. Her parents did not have diabetes, but their insulinogenic indices were low (0.25 and 0.3, respectively). We thought her early-onset diabetes was partly as a result of PAX6 mutation and partly because of an unknown insulin secretory defect inherited from her parents. We could not find any mutations in HNF-1alpha, -1beta, -4alpha, IPF-1, ISL-1, BEAT2/NeuroD1, PAX4, and amylin genes.

CONCLUSIONS

We report a case of PAX6 gene mutation with early-onset diabetes mellitus and aniridia. Low insulin secretory capacity in her parents suggested that her insulin secretory defect is as a result of not only PAX6 mutation but other genetic factors inherited from her parents.

Visualization of glucocorticoid receptor in the brain of green fluorescent protein–glucocorticoid receptor knockin mice

Glucocorticoids exert various neuroendocrinological effects, including stress response, in the central nervous system via glucocorticoid receptor (GR). GRs are transported from the cytoplasm to the nucleus upon ligand binding, and then exert the transcriptional activity. Although it is important for unraveling the actual property of the GR in vivo, subcellular dynamics of the GR are still unclear within the brain tissue in which the neuronal circuitry is maintained. To address this issue, we generated green fluorescent protein (GFP)-GR knockin mice, whose GR has been replaced by a GFP-GR fusion protein that is functionally indistinguishable from endogenous GR. In fixed brain sections of the GFP-GR knockin mice, the distribution of the green fluorescence was similar to that of GR immunoreactivity. By subtracting autofluorescence using fluorescent emission fingerprinting method with confocal laser scanning microscope, nuclear localization of GFP-GR was identifiable in the hippocampal CA3 subregion, where subcellular localization of the GR has been unsolved compared with other areas. To examine the subcellular trafficking of GFP-GR in vivo, we performed adrenalectomy on the GFP-GR knockin mice. GFP-GR was translocated from the nucleus to the cytoplasm and neurites two days after adrenalectomy. Furthermore, laser scanning cytometry by which fluorescence intensity in situ can be quantitatively measured revealed the entire GFP-GR expression level was increased. We then examined the dynamic changes in the subcellular localization of GFP-GR in living hippocampal neurons both in dissociated culture and in tissue slices. GFP-GR was localized in not only the perikarya but also neurites in the absence of ligand, and nuclear translocation following ligand treatment was observed. This is the first report visualizing subcellular trafficking of the GR in the mouse brain in more physiological condition. The present results propose new avenues for the research of the GR dynamics both in vitro and in vivo.

IL-10 is not required to prevent immune hyperactivity during memory responses to Toxoplasma gondii

Primary infection of IL-10 knockout (KO) mice with the protozoan parasite Toxoplasma gondii leads to a CD4(+)-T-cell dependent shock-like reaction with high systemic levels of IL-12 and IFN-gamma, severe liver pathology and death of mice. In the present study, this immune-mediated pathology was prevented by treatment of IL-10 KO mice with the anti-parasitic drug sulfadiazine, allowing these mice to progress to the chronic phase of infection. To address the role of endogenous IL-10 in the regulation of secondary immune responses to T. gondii, IL-10 KO mice were infected with the avirulent Me49 strain of this parasite, treated with sulfadiazine for 2 weeks starting at day 3 p.i., and were rechallenged 6 weeks p.i. with RH, a highly virulent strain of T. gondii. In these studies, chronically infected IL-10 KO mice survived secondary infection with RH and controlled parasite load. Although serum levels of IL-12 and IFN-gamma were higher in IL-10 KO mice than in wild type (WT) mice 8 days after RH rechallenge, these levels were well controlled in the absence of endogenous IL-10, suggesting that IL-10 is not required to down-regulate cytokine production during the memory response. Antigen-specific ex vivo recall responses further revealed that splenocytes from chronically infected WT and IL-10 KO mice responded to parasite antigen with similar production of IL-12 and IFN-gamma, and there was also no significant difference in ex vivo production of these cytokines by splenocytes in response to parasite antigen 7 days after secondary infection with T. gondii. Furthermore, IL-10 KO mice immunized with the Ts-4 vaccine-strain of T. gondii were protected when rechallenged with the virulent RH strain. Together, these studies demonstrate that the inhibitory effect of IL-10, which is required to prevent immune-mediated pathology during primary infection, is not required to prevent immune hyperactivity during a secondary response to T. gondii, and a highly effective memory response is generated in the absence of endogenous IL-10.

Effective doses of vecuronium in a patient with myotonic dystrophy*

Of the forms of muscular dystrophy, myotonic dystrophy has the greatest systemic involvement. Although most patients with myotonic dystrophy show normal sensitivity to non-depolarising neuromuscular blocking drugs, some have been reported to show greatly increased sensitivity to these drugs, and little is known about the sensitivity of different muscles. We compared effective doses of vecuronium in a patient with myotonic dystrophy at the orbicularis oculi, adductor pollicis and flexor hallucis brevis muscles during total intravenous anaesthesia. The calculated ED50 for the orbicularis oculi (7.77 microg x kg(-1) (95% CI 3.10-16.8 microg x kg(-1))) was lower than for the adductor pollicis (25.3 microg x kg(-1) (95% CI 20.7-43.3 microg x kg(-1))) and flexor hallucis brevis muscles (29.5 microg x kg(-1) (95% CI 11.0-85.6 microg x kg(-1); p < 0.01)). The ED90 was also lower for the orbicularis oculi (35.7 microg x kg(-1) (95% CI 14.8-66.5 microg x kg(-1))) than for the other muscles (51.8 microg x kg(-1) (95% CI 29.3-145.0 microg x kg(-1)) and 50.6 microg x kg(-1) (95% CI 5.29-642.0 microg x kg(-1)), respectively) (p < 0.01)).

Epidemiology of malignant neoplasms in soft tissue during childhood

Employing the data of the Hokkaido Children's Cancer Registry, incidences of malignant neoplasms in soft tissue during childhood were estimated. During 25 years (1975--1999), a total of 110 such cases (0-14 years of age) were registered. The average incidence was 0.40 per 100,000 population aged 0-14 years. The incidence of rhabdomyosarcoma (RMS) was 0.24, accounting for 60% of all malignant neoplasms in soft tissue. 30% of the malignant neoplasms in soft tissue were found in the head/face/neck. The share of RMS in the upper limbs was 76%, while that in the chest was 25%. Mortality due to malignant neoplasms in soft tissue was estimated using the data of vital statistics of all Japan. The average mortality of all malignant neoplasms in soft tissue was about 0.15 per 100,000 population aged 0-14 years, which was almost constant throughout the 25 years. Both the mortality at 5-9 years of age and that at age 10-14 years increased, while that at 0-4 years had a tendency to decrease. The prolongation of the survival period in the 0-4-year age group due to the progress in therapy may have brought about a shift of the age at death to older age groups, leading to a decrease in the mortality at 0-4 years of age.

Effects of neuromuscular-blocking drugs in rats in vivo: direct measurements in the diaphragm and tibialis anterior muscle

BACKGROUND

Effects of neuromuscular-blocking drugs are often investigated in rodents using both the diaphragm in vitro and the tibialis anterior muscle in vivo. Differences in the properties of these muscles cannot be neglected. We evaluated the neuromuscular effects of drugs on the rat diaphragm in vivo in comparison with the tibialis anterior muscle, directly measuring twitch tension with a force transducer.

METHODS

Respectively using sternotomy and an approach via the gluteal space, transducers were attached to the diaphragm and the tibialis anterior muscle. Phrenic and sciatic nerves were stimulated supramaximally by single square pulses to record isometric contraction of muscles. Pancuronium, vecuronium, or rocuronium was infused continuously at a rate adjusted repeatedly until stable tension was obtained. Effective doses for 50% (ED 50) and 90% (ED 90) depression of tension were calculated, using a cumulative infusion dosing method.

RESULTS

Isometric contraction of the diaphragm could be recorded despite movements of the heart and lungs. For all three drugs, both mean ED 50 and ED 90 were more than twice as large for the diaphragm as for the tibialis anterior (P<0.05). In addition, slopes of dose-response curves for the diaphragm were significantly less steep than those of the tibialis anterior for the three drugs.

CONCLUSION

Neuromuscular-blocking effects on the diaphragm can be recorded in vivo. According to direct contractile force measurement, the diaphragm is more resistant to non-depolarizing neuromuscular-blocking drugs than the tibialis anterior muscle.

Ocular surface epithelium induces expression of human mucosal lymphocyte antigen (HML-1) on peripheral blood lymphocytes

BACKGROUND/AIMS

Peripheral blood CD8+ lymphocytes that home to mucosal surfaces express the human mucosal lymphocyte antigen (HML-1). At mucosal surfaces, including the ocular surface, only intraepithelial CD8+ lymphocytes express HML-1. These lymphocytes are retained in the intraepithelial compartment by virtue of the interaction between HML-1 and its natural ligand, E-cadherin, which is expressed on epithelial cells. The purpose of this study was to determine whether ocular surface epithelial cells (ocular mucosa) could induce the expression of human mucosal lymphocyte antigen on peripheral blood lymphocytes.

METHODS

Human corneal and conjunctival epithelial cells were co-cultured with peripheral blood lymphocytes. Both non-activated and activated lymphocytes were used in the experiments. After 7 days of incubation, lymphocytes were recovered and analysed for the antigens CD8/HML-1, CD4/HML-1, CD3/CD8, CD3/CD4, CD3/CD25, CD8/CD25, and CD4/CD25 by flowcytometry.

RESULTS

Significant statistical differences were observed in the CD8/HML-1 expression when conjunctival epithelial cells were co-cultured with non-activated and activated lymphocytes (p = 0.04 for each) and when corneal epithelial cells were co-cultured with non-activated lymphocytes (p = 0.03). Significant statistical difference in CD4/HML-1 expression was observed only when conjunctival epithelial cells were co-cultured with activated lymphocytes (p = 0.02).

CONCLUSION

Ocular surface epithelial cells can induce the expression of human mucosal lymphocyte antigen on CD8+ (and to some extent on CD4+) lymphocytes. This may allow the retention of CD8+ and CD4+ lymphocytes within the epithelial compartment of the conjunctiva and play a part in mucosal homing of lymphocytes.

Is the mass screening for neuroblastoma ineffective?

Though a recent study (Schilling et al. 2002) concluded that the mass screening for neuroblastoma targeting children age 12 months was ineffective, we pointed out several serious problems and reestimated its effectiveness using their data. They employed the subjects in the "control area" as controls, not the "non-participants" whose biases are fewer because their area is the same as that of the participants. The incidence of neuroblastoma among the subjects in the "control area" was about 25% smaller than that of the "non-participants". This leads to underestimation of the effectiveness of the mass screening. They combined false negatives with true positives to calculate the incidence of the "screened group". But since many spontaneous regression cases are included in the true positives, this method inflates the incidence of the "screened group", leading to underestimation of the effectiveness of the mass screening. When the false negatives are compared with the non-participants, the incidence of the cases in stage 4 among the latter is about 40% of that of the former, and the mortality is less than two-thirds. The percentage of spontaneous regression cases among the true positives is estimated to be about 40%. These results are better than those of the Japanese screening programs (targeting infants age 6 months), supporting the effectiveness of mass screening for neuroblastoma.

Dedifferentiation and decreased expression of adhesion molecules, E-cadherin and ZO-1, in colorectal cancer are closely related to liver metastasis

Carcinoma cells with high metastatic potential often show a dedifferentiated phenotype at the primary site. In this study, a total of 48 cases (24 primary tumors of colorectal cancer (Pr-CRC) with liver metastasis, 24 without) were examined for E-cadherin and ZO-1 expression by immunohistochemical staining, and for their dedifferentiated phenotype. The expression levels of E-cadherin and ZO-1 were markedly decreased in the cancer cells of tumors with liver metastasis. Moreover, dedifferentiation of cancer cells, which was evaluated by the modified Gleason score, was also related to liver metastasis. However, none of the conventional clinicopathologic parameters of invasion, except lymph node metastasis, showed any relationship with liver metastasis. These results indicate that dedifferentiation and a decreased expression of E-cadherin and ZO-1 are closely related to liver metastasis.

Dynamic shear properties of the temporomandibular joint disc

Shear stress might be an important factor associated with fatigue failure and damage of the temporomandibular joint disc. Little information, however, is available on the dynamic behavior of the disc in shear. Since the disc is an anisotropic and viscoelastic structure, in the present study the dependency of the dynamic shear behavior on the direction and frequency of loading was examined. Ten porcine discs were used for dynamic shear tests. Shear stress was applied in both anteroposterior (A-P test) and mediolateral (M-L test) directions. The dynamic moduli increased as the loading frequency increased. The dynamic elasticity was significantly larger in the A-P test than in the M-L test, although the dynamic viscosity was similar in both tests. The present results suggest that non-linearities, compression/shear coupling, and intrinsic viscoelasticity affect the shear material behavior of the disc, which might have important implications for the transmission of load in the temporomandibular joint.

Sequence analysis of the pro-opiomelanocortin (POMC) gene in obese/diabetic Japanese

Pro-opiomelanocortin (POMC)-derived peptides play a critical role in body weight regulation in the central nervous system. Mice deficient in POMC developed obesity. We sought mutations in the POMC gene in 50 morbidly obese (body mass index 35-60 kg/m(2)) Japanese subjects with diabetes by direct sequencing. Apart from two silent mutations (C6982T and C7285T), no other mutations were detected. Frequencies of these mutations were not significantly different between 100 obese subjects and 100 controls. Also, the frequencies did not differ in the subjects with or without diabetes. These results suggest that mutations in the POMC gene are unlikely to be a major factor of obesity or diabetes in Japanese subjects.

Steroid effects on secretion from subsets of lactotrophs: role of folliculo-stellate cells and annexin 1

Prolactin secretion is controlled by the hypothalamus, and by circulating steroids; oestrogens stimulate, but glucocorticoids inhibit prolactin release. Lactotrophs express intracellular receptors for oestrogens, but apparently not glucocorticoids. Therefore, a genomic effect of oestrogens could be direct, but that of glucocorticoids appears to be indirect. Lactotrophs are not a homogeneous cell population: some have large irregular dense-cored vesicles, others have small round vesicles, but the functional significance of this inhomogeneity is far from clear. Oestradiol and testosterone can stimulate rapid release of prolactin selectively from type II lactotrophs characterised by small round vesicles. Progesterone and other steroids do not exert this effect, which results from a non-genomic action of oestradiol and testosterone. Glucocorticoid inhibition of secretagogue-induced prolactin secretion is mimicked by annexin 1 (lipocortin 1), a protein induced by glucocorticoids in the pituitary and many other tissues, and can be blocked by annexin 1 immunoneutralisation and antisense. Glucocorticoid inhibition of ACTH and growth hormone secretion also involves annexin 1. Pituitary annexin 1 is located in folliculo-stellate cells; these express glucocorticoid receptors, and glucocorticoids induce annexin-1 synthesis. Annexin 1 is externalised from folliculo-stellate cells in response to glucocorticoids, despite the fact that it lacks a secretory signal sequence and is not packaged in vesicles. Inhibition of annexin 1 externalisation by glyburide suggests involvement of an ABC (ATP-binding cassette) transporter in externalisation. Both oestradiol and glucocorticoids therefore influence the secretion of prolactin by novel direct and indirect mechanisms, in addition to their much better understood effects on transcription via classical intracellular steroid receptors.

Contribution of HPLC mass screening for neuroblastoma to a decrease in mortality

The aim of this study is the estimation of the contribution of HPLC mass screening for neuroblastoma to the decrease in deaths due to this disease. The mortality rates of malignant neoplasms of the adrenal glands (ICD 9, 1940; ICD 10, C74; virtually all the cases of these codes are neuroblastoma during childhood) at 1-4 years of age in cohorts born in 1979-1984, 1985-1988, and 1989-1992 in the whole of Japan were calculated, using data obtained from the Ministry of Health and Welfare. The numbers of infants screened by HPLC in the cohorts were estimated through the reports of the Ministry of Health and Welfare and the database of the Japanese Society for Mass-screening. The mortality of the cohort born in 1989-1992, in which 77.8% of the live births were screened by HPLC, was 1.73 per 100,000 live births. This is about half of that (3.26) of the cohort born in 1979-1984, in which few infants were screened. On the assumption that cases of the 1985-1988 and 1989-1992 cohorts died according to the mortality rate of the 1979-1984 cohort, the expected numbers of deaths were estimated; that for the 1985-1988 cohort was 178.51 (of them, that for the infants screened by HPLC was 39.65), and that for the 1989-1992 cohort was 159.78 (of them, that for the infants screened by HPLC was 124.33). The observed numbers of deaths were 145 and 85, respectively. Assuming that non-HPLC methods have no effects and using 2 unknown quantities x (contribution of HPLC) and y (other factors), simultaneous equations (1) 178.51 - 39.65x - 178.51y = 145 and (2) 159.78 - 124.33x - 159.78y = 85 were made. Solving them, x = 0.5041 and y = 0.0757 were obtained. In conclusion HPLC screening targeting infants aged 6 months reduces death of adrenal neuroblastomas at 1-4 years of age by about 50%.

Store-operated Ca2+ entry uncoupled with ryanodine receptor and junctional membrane complex in heart muscle cells

Store-operated Ca2+ entry (SOCE) is the Ca2+ influx that is activated on depletion of intracellular Ca2+ stores. Although SOCE is found in a variety of cell types, its activation mechanism and molecular identity remain to be clarified. Current experimental results suggest that SOCE channels are activated by direct coupling with Ca2+ release channels on depleted stores. Here we report SOCE in cardiac myocytes, that was prominently sensitive to Zn2+ but resistant to inhibitors for voltage-dependent Ca2+ channels and Na+/Ca2+ exchangers. The SOCE activity may be developmentally regulated, because the SOCE was easily detected during embryonic and neonatal stages but not in mature myocytes from adult hearts. In cardiac myocytes, ryanodine receptor type 2 (RyR-2) is thought to be the sole Ca2+ release channel on the intracellular store, and junctophilin type 2 (JP-2) contributes to formation of the junctional complex between the cell surface and store membranes. Using the knockout mice, we also examined possible involvement of the Ca2+ release channel and junctional membrane complex in cardiac SOCE. Apparently normal SOCE activities were retained in mutant myocytes lacking RyR-2 or JP-2, suggesting that neither the Ca2+ release channel nor junctional membrane complex is involved in activation of cardiac SOCE.

Motoneuron-specific expression of NR3B, a novel NMDA-type glutamate receptor subunit that works in a dominant-negative manner

We have identified a novel glutamate receptor subunit on the human and mouse genome. Cloning of the mouse cDNA revealed a protein consisting of 1003 amino acids encoded by at least nine exons. This protein showed the highest similarity (51%) to the NR3A subunit of the NMDA receptor and therefore was termed NR3B. NR3B has a structure typical of glutamate receptor family members with a signal peptide and four membrane-associated regions. Amino acids forming a ligand-binding pocket are conserved. When coexpressed with NR1 and NR2A in heterologous cells, NR3B suppressed glutamate-induced current similarly to NR3A. Thus members of the NR3 class of NMDA receptors act as dominant-negative subunits in the NMDA receptor complex. NR3B shows very restricted expression in somatic motoneurons of the brainstem and spinal cord. Its expression in other types of motoneurons, including autonomic motoneurons in Onuf's nucleus and oculomotor neurons, is significantly weaker. Our results indicate that NR3B is important as a regulatory subunit that controls NMDA receptor transmission in motoneurons. It may be involved in the pathogenesis of neurodegenerative diseases involving motoneurons as well.

Abnormal formation of sarcoplasmic reticulum networks and triads during early development of skeletal muscle cells in mitsugumin29-deficient mice

Recently, we detected a novel membrane protein, mitsugumin29 (MG29), in the triads in rabbit skeletal muscle cells and suggested important roles for this membrane protein in the formation of the sarcoplasmic reticulum (SR) networks and triads in muscle cells. In the present study, we examined the development of skeletal muscle cells in MG29-deficient mice to try to determine the roles played by MG29 in the formation of the SR networks and triads. Ultrastructural observations revealed some morphological abnormalities in these mice, such as incomplete formation of the SR networks, an irregular running of the transverse tubule and a partial defect in the triads at the A-I junctional region. These ultrastructural abnormalities occurred during early myogenesis and were preserved until the adult stage. The possible roles for MG29 in the formation of SR networks and triads in skeletal muscle cells are discussed in the light of these observations.

Ultrashort-laser-pulse-induced persistent spectral hole burning of Eu(3+) in sodium borate glasses

We have observed persistent spectral hole burning (PSHB) in Eu(3+) -doped sodium borate glasses irradiated with near-IR femtosecond laser pulses. As-prepared glasses, i.e., glasses melted in air, do not show PSHB even at low temperatures (~77K) , but room-temperature PSHB occurs in the irradiated glasses. The exposure to IR radiation causes both the reduction of Eu(3+) to Eu(2+) and the formation of intrinsic defects. We propose that the photoinduced redistribution of electric charges between Eu(3+) to Eu(2+) is responsible for the occurrence of PSHB.

Association of plasma free-3-methoxy-4-hydroxyphenyl (ethylene)glycol, natural killer cell activity and delirium in postoperative patients

We measured and compared levels of plasma free 3-methoxy-4-hydroxyphenyl (ethylene)glycol (pMHPG), a major metabolite of noradrenaline, and natural killer (NK) cell activity in 26 patients prior to their undergoing an operation for cardiovascular diseases; 11 of whom expressed delirium and 15 who did not. In conclusion, we found that pMHPG levels before an operation were higher in patients with postoperative delirium than in the patients without, while NK cell activity showed no difference between the two groups. It is possible that hyperactivity of noradrenargic neurons is connected with the development of postoperative delirium. Furthermore, we considered that measurement of pMHPG level before operation might be a useful tool to predict the occurrence of postoperative delirium.