PHF2 regulates sarcomeric gene transcription in myogenesis

Myogenesis is regulated mainly by transcription factors known as Myogenic Regulatory Factors (MRFs), and the transcription is affected by epigenetic modifications. However, the epigenetic regulation of myogenesis is poorly understood. Here, we focused on the epigenomic modification enzyme, PHF2, which demethylates histone 3 lysine 9 dimethyl (H3K9me2) during myogenesis. Phf2 mRNA was expressed during myogenesis, and PHF2 was localized in the nuclei of myoblasts and myotubes. We generated Phf2 knockout C2C12 myoblasts using the CRISPR/Cas9 system and analyzed global transcriptional changes via RNA-sequencing. Phf2 knockout (KO) cells 2 d post differentiation were subjected to RNA sequencing. Gene ontology (GO) analysis revealed that Phf2 KO impaired the expression of the genes related to skeletal muscle fiber formation and muscle cell development. The expression levels of sarcomeric genes such as Myhs and Mybpc2 were severely reduced in Phf2 KO cells at 7 d post differentiation, and H3K9me2 modification of Mybpc2, Mef2c and Myh7 was increased in Phf2 KO cells at 4 d post differentiation. These findings suggest that PHF2 regulates sarcomeric gene expression via epigenetic modification.

Morin improves dexamethasone-induced muscle atrophy by modulating atrophy-related genes and oxidative stress in female mice

This study investigated the effect of morin, a flavonoid, on dexamethasone-induced muscle atrophy in C57BL/6J female mice. Dexamethasone (10 mg/kg body weight) for 10 days significantly reduced body weight, gastrocnemius and tibialis anterior muscle mass, and muscle protein in mice. Dexamethasone significantly upregulated muscle atrophy-associated ubiquitin ligases, including atrogin-1 and MuRF-1, and the upstream transcription factors FoxO3a and Klf15. Additionally, dexamethasone significantly induced the expression of oxidative stress-sensitive ubiquitin ligase Cbl-b and the accumulation of the oxidative stress markers malondialdehyde and advanced protein oxidation products in both the plasma and skeletal muscle samples. Intriguingly, morin treatment (20 mg/kg body weight) for 17 days effectively attenuated the loss of muscle mass and muscle protein and suppressed the expression of ubiquitin ligases while reducing the expression of upstream transcriptional factors. Therefore, morin might act as a potential therapeutic agent to attenuate muscle atrophy by modulating atrophy inducing genes and preventing oxidative stress.

MuRF1 deficiency prevents age-related fat weight gain, possibly through accumulation of PDK4 in skeletal muscle mitochondria in older mice

Recent studies show that muscle mass and metabolic function are interlinked. Muscle RING finger 1 (MuRF1) is a critical muscle-specific ubiquitin ligase associated with muscle atrophy. Yet, the molecular target of MuRF1 in atrophy and aging remains unclear. We examined the role of MuRF1 in aging, using MuRF1-deficient (MuRF1^-/- ) mice in vivo, and MuRF1-overexpressing cell in vitro. MuRF1 deficiency partially prevents age-induced skeletal muscle loss in mice. Interestingly, body weight and fat mass of more than 7-month-old MuRF1^-/- mice were lower than in MuRF1^+/+ mice. Serum and muscle metabolic parameters and results of indirect calorimetry suggest significantly higher energy expenditure and enhanced lipid metabolism in 3-month-old MuRF1^-/- mice than in MuRF1^+/+ mice, resulting in suppressed adipose tissue gain during aging. Pyruvate dehydrogenase kinase 4 (PDK4) is crucial for a switch from glucose to lipid metabolism, and the interaction between MuRF1 and PDK4 was examined. PDK4 protein levels were elevated in mitochondria from the skeletal muscle in MuRF1^-/- mice. In vitro, MuRF1 interacted with PDK4 but did not induce degradation through ubiquitination. Instead, SUMO posttranscriptional modification (SUMOylation) of PDK4 was detected in MuRF1-overexpressing cells, in contrast to cells without the RING domain of MuRF1. MuRF1 deficiency enhances lipid metabolism possibly by upregulating PDK4 localization into mitochondrial through prevention of SUMOylation. Inhibition of MuRF1-mediated PDK4 SUMOylation is a potential therapeutic target for age-related dysfunction of lipid metabolism and muscle atrophy.

Additional effects of simultaneous treatment with C14-Cblin and celastrol on the clinorotation-induced rat L6 myotube atrophy

Two novel reagents, N-myristoylated Cbl-b inhibitory peptide (C14-Cblin) and celastrol, a quinone methide triterpene, are reported to be effective in preventing myotube atrophy. The combined effects of C14-Cblin and celastrol on rat L6 myotubes atrophy induced by 3D-clinorotation, a simulated microgravity model, was investigated in the present study. We first examined their effects on expression in atrogenes. Increase in MAFbx1/atrogin-1 and MuRF-1 by 3D-clinorotation was significantly suppressed by treatment with C14-Cblin or celastrol, but there was no additive effect of simultaneous treatment. However, celastrol significantly suppressed the upregulation of Cbl-b and HSP70 by 3D-clinorotation. Whereas 3D-clinorotation decreased the protein level of IRS-1 in L6 myotubes, C14-Cblin and celastrol inhibited the degradation of IRS-1. C14-Cblin and celastrol promoted the phosphorylation of FOXO3a even in microgravity condition. Simultaneous administration of C14-Cblin and celastrol had shown little additive effect in reversing the impairment of IGF-1 signaling by 3D-clinorotation. While 3D-clinorotation-induced marked oxidative stress in L6 myotubes, celastrol suppressed 3D-clinorotation-induced ROS production. Finally, the C14-Cblin and celastrol-treated groups were inhibited decrease in L6 myotube diameter and increased the protein content of slow-twitch MyHC cultured under 3D-clinorotation. The simultaneous treatment of C14-Cblin and celastrol additively prevented 3D-clinorotation-induced myotube atrophy than single treatment. J. Med. Invest. 69 : 127-134, February, 2022.

All-trans retinoic acid changes muscle fiber type via increasing GADD34 dependent on MAPK signal

ATRA increases GADD34 expression by decreasing the expression of Six1, which down-regulates the transcriptional activity with TLE3 and increasing mRNA stability through blocking the interaction between TTP and ARE on GADD34 mRNA, resulting in muscle fiber type change.

All-trans retinoic acid (ATRA) increases the sensitivity to unfolded protein response in differentiating leukemic blasts. The downstream transcriptional factor of PERK, a major arm of unfolded protein response, regulates muscle differentiation. However, the role of growth arrest and DNA damage-inducible protein 34 (GADD34), one of the downstream factors of PERK, and the effects of ATRA on GADD34 expression in muscle remain unclear. In this study, we identified ATRA increased the GADD34 expression independent of the PERK signal in the gastrocnemius muscle of mice. ATRA up-regulated GADD34 expression through the transcriptional activation of GADD34 gene via inhibiting the interaction of homeobox Six1 and transcription co-repressor TLE3 with the MEF3-binding site on the GADD34 gene promoter in skeletal muscle. ATRA also inhibited the interaction of TTP, which induces mRNA degradation, with AU-rich element on GADD34 mRNA via p-38 MAPK, resulting in the instability of GADD34 mRNA. Overexpressed GADD34 in C2C12 cells changes the type of myosin heavy chain in myotubes. These results suggest ATRA increases GADD34 expression via transcriptional and post-transcriptional regulation, which changes muscle fiber type.

Uhrf1 governs the proliferation and differentiation of muscle satellite cells

DNA methylation is an essential form of epigenetic regulation responsible for cellular identity. In muscle stem cells, termed satellite cells, DNA methylation patterns are tightly regulated during differentiation. However, it is unclear how these DNA methylation patterns affect the function of satellite cells. We demonstrate that a key epigenetic regulator, ubiquitin like with PHD and RING finger domains 1 (Uhrf1), is activated in proliferating myogenic cells but not expressed in quiescent satellite cells or differentiated myogenic cells in mice. Ablation of Uhrf1 in mouse satellite cells impairs their proliferation and differentiation, leading to failed muscle regeneration. Uhrf1-deficient myogenic cells exhibited aberrant upregulation of transcripts, including Sox9, with the reduction of DNA methylation level of their promoter and enhancer region. These findings show that Uhrf1 is a critical epigenetic regulator of proliferation and differentiation in satellite cells, by controlling cell-type-specific gene expression via maintenance of DNA methylation.

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Uhrf1 is activated in proliferating myogenic cells

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Uhrf1 in satellite cells is required for muscle regeneration

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Ablation of Uhrf1 in satellite cells impairs their proliferation and differentiation

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Uhrf1 controls cell-type-specific transcripts via maintenance of DNA methylation

Morin attenuates dexamethasone-mediated oxidative stress and atrophy in mouse C2C12 skeletal myotubes

Glucocorticoids are the drugs most commonly used to manage inflammatory diseases. However, they are prone to inducing muscle atrophy by increasing muscle proteolysis and decreasing protein synthesis. Various studies have demonstrated that antioxidants can mitigate glucocorticoid-induced skeletal muscle atrophy. Here, we investigated the effect of a potent antioxidative natural flavonoid, morin, on the muscle atrophy and oxidative stress induced by dexamethasone (Dex) using mouse C2C12 skeletal myotubes. Dex (10 μM) enhanced the production of reactive oxygen species (ROS) in C2C12 myotubes via glucocorticoid receptor. Moreover, Dex administration reduced the diameter and expression levels of the myosin heavy chain protein in C2C12 myotubes, together with the upregulation of muscle atrophy-associated ubiquitin ligases, such as muscle atrophy F-box protein 1/atrogin-1, muscle ring finger protein-1, and casitas B-lineage lymphoma proto-oncogene-b. Dex also significantly decreased phosphorylated Foxo3a and increased total Foxo3a expression. Interestingly, Dex-induced ROS accumulation and Foxo3a expression were inhibited by morin (10 μM) pretreatment. Morin also prevented the Dex-induced reduction of myotube thickness, together with muscle protein degradation and suppression of the upregulation of atrophy-associated ubiquitin ligases. In conclusion, our results suggest that morin effectively prevents glucocorticoid-induced muscle atrophy by reducing oxidative stress.

Myofiber androgen receptor increases muscle strength mediated by a skeletal muscle splicing variant of Mylk4

Androgens have a robust effect on skeletal muscles to increase muscle mass and strength. The molecular mechanism of androgen/androgen receptor (AR) action on muscle strength is still not well known, especially for the regulation of sarcomeric genes. In this study, we generated androgen-induced hypertrophic model mice, myofiber-specific androgen receptor knockout (cARKO) mice supplemented with dihydrotestosterone (DHT). DHT treatment increased grip strength in control mice but not in cARKO mice. Transcriptome analysis by RNA-seq, using skeletal muscles obtained from control and cARKO mice treated with or without DHT, identified a fast-type muscle-specific novel splicing variant of Myosin light-chain kinase 4 (Mylk4) as a target of AR in skeletal muscles. Mylk4 knockout mice exhibited decreased maximum isometric torque of plantar flexion and passive stiffness of myofibers due to reduced phosphorylation of Myomesin 1 protein. This study suggests that androgen-induced skeletal muscle strength is mediated with Mylk4 and Myomesin 1 axis.

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DHT increases muscle strength through myofiber AR

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Myofiber AR increases a fast-type muscle-specific novel splicing variant of Mylk4

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MYLK4 regulates muscle strength and muscle stiffness

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MYLK4 induces phosphorylation of MYOM1

Myogenesis control by SIX transcriptional complexes

SIX homeoproteins were first described in Drosophila, where they participate in the Pax-Six-Eya-Dach (PSED) network with eyeless, eyes absent and dachsund to drive synergistically eye development through genetic and biochemical interactions. The role of the PSED network and SIX proteins in muscle formation in vertebrates was subsequently identified. Evolutionary conserved interactions with EYA and DACH proteins underlie the activity of SIX transcriptional complexes (STC) both during embryogenesis and in adult myofibers. Six genes are expressed throughout muscle development, in embryonic and adult proliferating myogenic stem cells and in fetal and adult post-mitotic myofibers, where SIX proteins regulate the expression of various categories of genes. In vivo, SIX proteins control many steps of muscle development, acting through feedforward mechanisms: in the embryo for myogenic fate acquisition through the direct control of Myogenic Regulatory Factors; in adult myofibers for their contraction/relaxation and fatigability properties through the control of genes involved in metabolism, sarcomeric organization and calcium homeostasis. Furthermore, during development and in the adult, SIX homeoproteins participate in the genesis and the maintenance of myofibers diversity.

GPRC5A facilitates cell proliferation through cell cycle regulation and correlates with bone metastasis in prostate cancer

The prognosis of patients with progressive prostate cancers that are hormone refractory and/or have bone metastasis is poor. Multiple therapeutic targets to improve prostate cancer patient survival have been investigated, including orphan GPCRs. In our study, we identified G Protein-Coupled Receptor Class C Group 5 Member A (GPRC5A) as a candidate therapeutic molecule using integrative gene expression analyses of registered data sets for prostate cancer cell lines. Kaplan-Meier analysis of TCGA data sets revealed that patients who have high GPRC5A expression had significantly shorter overall survival. PC3 prostate cancer cells with CRISPR/Cas9-mediated GPRC5A knockout exhibited significantly reduced cell proliferation both in vitro and in vivo. RNA-seq revealed that GPRC5A KO PC3 cells had dysregulated expression of cell cycle-related genes, leading to cell cycle arrest at the G2/M phase. Furthermore, the registered gene expression profile data set showed that the expression level of GPRC5A in original lesions of prostate cancer patients with bone metastasis was higher than that without bone metastasis. In fact, GPRC5A KO PC3 cells failed to establish bone metastasis in xenograft mice models. In addition, our clinical study revealed that GPRC5A expression levels in prostate cancer patient samples were significantly correlated with bone metastasis as well as the patient's Gleason score (GS). Combined assessment with the immunoreactivity of GPRC5A and GS displayed higher specificity for predicting the occurrence of bone metastasis. Together, our findings indicate that GPRC5A can be a possible therapeutic target and prognostic marker molecule for progressive prostate cancer.

Microdetermination of Sialic Acids in Blood Samples by Hydrophilic Interaction Chromatography Coupled to Post-column Derivatization and Fluorometric Detection

An analytical method for the determination of sialic acids in biological samples has been developed and applied to fetal bovine serum (FBS), newborn calf serum and adult bovine serum. The hydrolysis of sera was carried out and the liberated sialic acids were quantified using a rapid and sensitive HPLC. The HPLC includes the separation and detection of N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc) using hydrophilic interaction liquid chromatography and a fluorometric post-column reaction with 2-cyanoacetamide. The calibration graphs for Neu5Ac and Neu5Gc were linear over the range of 10 pmol - 5 nmol. The concentrations of sialic acids in FBS, newborn calf serum and adult bovine serum were 5.06, 3.79 and 1.64 mM, respectively. The ratios of Neu5Gc and Neu5Ac changed dramatically according to the development stages. The present method has a satisfactory sensitivity in the quantification of Neu5Ac and Neu5Gc in serum samples. It seems that this analytical system can therefore be applied for routine use in clinical investigations of serum sialylation changes in cancer patients.

Uhrf1 is indispensable for normal limb growth by regulating chondrocyte differentiation through specific gene expression

Transcriptional regulation can be tightly orchestrated by epigenetic regulators. Among these, ubiquitin-like with PHD and RING finger domains 1 (Uhrf1) is reported to have diverse epigenetic functions, including regulation of DNA methylation. However, the physiological functions of Uhrf1 in skeletal tissues remain unclear. Here, we show that limb mesenchymal cell-specific Uhrf1 conditional knockout mice (Uhrf1^{ΔLimb/ΔLimb} ) exhibit remarkably shortened long bones that have morphological deformities due to dysregulated chondrocyte differentiation and proliferation. RNA-seq performed on primary cultured chondrocytes obtained from Uhrf1^{ΔLimb/ΔLimb} mice showed abnormal chondrocyte differentiation. In addition, integrative analyses using RNA-seq and MBD-seq revealed that Uhrf1 deficiency decreased genome-wide DNA methylation and increased gene expression through reduced DNA methylation in the promoter regions of 28 genes, including Hspb1, which is reported to be an IL1-related gene and to affect chondrocyte differentiation. Hspb1 knockdown in cKO chondrocytes can normalize abnormal expression of genes involved in chondrocyte differentiation, such as Mmp13 These results indicate that Uhrf1 governs cell type-specific transcriptional regulation by controlling the genome-wide DNA methylation status and regulating consequent cell differentiation and skeletal maturation.

Corrigendum: The CUL3-SPOP-DAXX axis is a novel regulator of VEGFR2 expression in vascular endothelial cells

This corrects the article DOI: 10.1038/srep42845.

Six1 homeoprotein drives myofiber type IIA specialization in soleus muscle

BACKGROUND

Adult skeletal muscles are composed of slow and fast myofiber subtypes which each express selective genes required for their specific contractile and metabolic activity. Six homeoproteins are transcription factors regulating muscle cell fate through activation of myogenic regulatory factors and driving fast-type gene expression during embryogenesis.

RESULTS

We show here that Six1 protein accumulates more robustly in the nuclei of adult fast-type muscles than in adult slow-type muscles, this specific enrichment takes place during perinatal growth. Deletion of Six1 in soleus impaired fast-type myofiber specialization during perinatal development, resulting in a slow phenotype and a complete lack of Myosin heavy chain 2A (MyHCIIA) expression. Global transcriptomic analysis of wild-type and Six1 mutant myofibers identified the gene networks controlled by Six1 in adult soleus muscle. This analysis showed that Six1 is required for the expression of numerous genes encoding fast-type sarcomeric proteins, glycolytic enzymes and controlling intracellular calcium homeostasis. Parvalbumin, a key player of calcium buffering, in particular, is a direct target of Six1 in the adult myofiber.

CONCLUSIONS

This analysis revealed that Six1 controls distinct aspects of adult muscle physiology in vivo, and acts as a main determinant of fast-fiber type acquisition and maintenance.

MyoD reprogramming requires Six1 and Six4 homeoproteins: genome-wide cis-regulatory module analysis

Myogenic regulatory factors of the MyoD family have the ability to reprogram differentiated cells toward a myogenic fate. In this study, we demonstrate that Six1 or Six4 are required for the reprogramming by MyoD of mouse embryonic fibroblasts (MEFs). Using microarray experiments, we found 761 genes under the control of both Six and MyoD. Using MyoD ChIPseq data and a genome-wide search for Six1/4 MEF3 binding sites, we found significant co-localization of binding sites for MyoD and Six proteins on over a thousand mouse genomic DNA regions. The combination of both datasets yielded 82 genes which are synergistically activated by Six and MyoD, with 96 associated MyoD+MEF3 putative cis-regulatory modules (CRMs). Fourteen out of 19 of the CRMs that we tested demonstrated in Luciferase assays a synergistic action also observed for their cognate gene. We searched putative binding sites on these CRMs using available databases and de novo search of conserved motifs and demonstrated that the Six/MyoD synergistic activation takes place in a feedforward way. It involves the recruitment of these two families of transcription factors to their targets, together with partner transcription factors, encoded by genes that are themselves activated by Six and MyoD, including Mef2, Pbx-Meis and EBF.

Clinical Data Interchange Standards Consortium Standardization of Biobank Data: A Feasibility Study

The National Center Biobank Network (NCBN), consisting of six national centers (NCs) for advanced and specialized medical care, was launched in Japan in 2012 to collect biological specimens and health-related data. The common data formats of the six NCs, however, are not widely known outside the NCs. Therefore, we investigated whether the data elements collected by the NCBN could be made to conform to the international standards of the Clinical Data Interchange Standards Consortium (CDISC). We attempted to map the NCBN data elements (202 items) onto the Study Data Tabulation Model (SDTM), a set of CDISC standards on the submission format of electronic clinical data approved by the Food and Drug Administration. The results showed that all 202 items of the NCBN data could be mapped onto the SDTM and fulfilled 50%-70% of the required items of each domain specified in the SDTM. We concluded that, while the standardization of biobank data according to the CDISC standards is possible, there is a need to consider whether additional items must be included in the NCBN and to have experts familiar with the CDISC standards review the standardization needs.

Six homeoproteins and a Iinc-RNA at the fast MYH locus lock fast myofiber terminal phenotype

Thousands of long intergenic non-coding RNAs (lincRNAs) are encoded by the mammalian genome. However, the function of most of these lincRNAs has not been identified in vivo. Here, we demonstrate a role for a novel lincRNA, linc-MYH, in adult fast-type myofiber specialization. Fast myosin heavy chain (MYH) genes and linc-MYH share a common enhancer, located in the fast MYH gene locus and regulated by Six1 homeoproteins. linc-MYH in nuclei of fast-type myofibers prevents slow-type and enhances fast-type gene expression. Functional fast-sarcomeric unit formation is achieved by the coordinate expression of fast MYHs and linc-MYH, under the control of a common Six-bound enhancer.

Analysis of DNA repair and protection in the Tardigrade Ramazzottius varieornatus and Hypsibius dujardini after exposure to UVC radiation

Tardigrades inhabiting terrestrial environments exhibit extraordinary resistance to ionizing radiation and UV radiation although little is known about the mechanisms underlying the resistance. We found that the terrestrial tardigrade Ramazzottius varieornatus is able to tolerate massive doses of UVC irradiation by both being protected from forming UVC-induced thymine dimers in DNA in a desiccated, anhydrobiotic state as well as repairing the dimers that do form in the hydrated animals. In R. varieornatus accumulation of thymine dimers in DNA induced by irradiation with 2.5 kJ/m² of UVC radiation disappeared 18 h after the exposure when the animals were exposed to fluorescent light but not in the dark. Much higher UV radiation tolerance was observed in desiccated anhydrobiotic R. varieornatus compared to hydrated specimens of this species. On the other hand, the freshwater tardigrade species Hypsibius dujardini that was used as control, showed much weaker tolerance to UVC radiation than R. varieornatus, and it did not contain a putative phrA gene sequence. The anhydrobiotes of R. varieornatus accumulated much less UVC-induced thymine dimers in DNA than hydrated one. It suggests that anhydrobiosis efficiently avoids DNA damage accumulation in R. varieornatus and confers better UV radiation tolerance on this species. Thus we propose that UV radiation tolerance in tardigrades is due to the both high capacities of DNA damage repair and DNA protection, a two-pronged survival strategy.

The preventive effect of Daikenchuto on postoperative adhesion-induced intestinal obstruction in rats

The present study investigated the effect of Daikenchuto (DKT) on postoperative intestinal adhesion in rats. We evaluated the effects of DKT, constituent medical herbs and active compounds on talc-induced intestinal adhesion in rats and DKT-induced contractions using isolated guinea pig ileum. DKT significantly prevented adhesion formation, and this action was inhibited by pretreatment with atropine or ruthenium red. The constituent medical herbs, Zanthoxylum Fruit and Maltose Syrup Powder significantly prevented adhesion formation. Moreover, hydroxy sanshool (HS) prevented adhesion formation, and this action was inhibited by pretreatment with ruthenium red. In contrast, DKT-induced contractions were inhibited by tetrodotoxin, atropine, and capsazepine. These results suggested that DKT had a preventive action on postoperative adhesive intestinal obstruction, and that this action was mediated by sensory and cholinergic nerves. Furthermore, HS was found to be one of the active compound of DKT, and its action was mediated by sensory nerves.

Cooperative interaction between hepatocyte nuclear factor 4 alpha and GATA transcription factors regulates ATP-binding cassette sterol transporters ABCG5 and ABCG8

Cholesterol homeostasis is maintained by coordinate regulation of cholesterol synthesis and its conversion to bile acids in the liver. The excretion of cholesterol from liver and intestine is regulated by ATP-binding cassette half-transporters ABCG5 and ABCG8. The genes for these two proteins are closely linked and divergently transcribed from a common intergenic promoter region. Here, we identified a binding site for hepatocyte nuclear factor 4alpha (HNF4alpha) in the ABCG5/ABCG8 intergenic promoter, through which HNF4alpha strongly activated the expression of a reporter gene in both directions. The HNF4alpha-responsive element is flanked by two conserved GATA boxes that were also required for stimulation by HNF4alpha. GATA4 and GATA6 bind to the GATA boxes, coexpression of GATA4 and HNF4alpha leads to a striking synergistic activation of both the ABCG5 and the ABCG8 promoters, and binding sites for HNF4alpha and GATA were essential for maximal synergism. We also show that HNF4alpha, GATA4, and GATA6 colocalize in the nuclei of HepG2 cells and that a physical interaction between HNF4alpha and GATA4 is critical for the synergistic response. This is the first demonstration that HNF4alpha acts synergistically with GATA factors to activate gene expression in a bidirectional fashion.

A neuropeptide ligand of the G protein-coupled receptor GPR103 regulates feeding, behavioral arousal, and blood pressure in mice

Here, we report the isolation and characterization of an endogenous peptide ligand of GPR103 from rat brains. The purified peptide was found to be the 43-residue RF-amide peptide QRFP. We also describe two mouse homologues of human GPR103, termed mouse GPR103A and GPR103B. QRFP binds and activates the human GPR103, as well as mouse GPR103A and GPR103B, with nanomolar affinities in transfected cells. Systematic in situ hybridization analysis in mouse brains showed that QRFP is expressed exclusively in the periventricular and lateral hypothalamus, whereas the two receptor mRNAs are distinctly localized in various brain areas without an overlap to each other. When administered centrally in mice, QRFP induced feeding behavior, accompanied by increased general locomotor activity and metabolic rate. QRFP-induced food intake was abolished by preadministration of BIBP3226, a specific antagonist for the Y1 neuropeptide Y receptor. Hypothalamic prepro-QRFP mRNA expression was up-regulated upon fasting and in genetically obese ob/ob and db/db mice. Central QRFP administration also evoked highly sustained elevation of blood pressure and heart rate. Our findings suggest that QRFP and GPR103A/B may regulate diverse neuroendocrine and behavioral functions and implicate this neuropeptide system in metabolic syndrome.

Age-related changes of intracellular Abeta in cynomolgus monkey brains

To confirm the intracellular accumulation of amyloid beta-protein (Abeta), we carefully performed immunohistochemistry using brains of cynomolgus monkeys of various ages. Cortical neurones and their large neurites were immunostained with antibodies against Abeta in young monkey brains. In aged monkey brains, intracellular Abeta localized within cortical neurones; no clear association was found between the presence of intracellular Abeta and senile plaques (SPs). Interestingly, we did not observe Abeta-immunoreactive cortical neurones in brains fixed with neutral buffered formalin. Western blot analyses of microsomal and nerve ending fractions derived from the brains of young to aged monkeys revealed that intracellular Abeta generation changed with age. In the microsomal fraction, the amount of Abeta42 significantly increased in brains from older monkeys (>30 years of age), and the amount of Abeta43 significantly decreased with age in the microsomal fraction. The amount of Abeta40 remained the same regardless of age. Biochemical analyses also showed that intracellular levels of each of these Abeta molecules significantly increased with age in nerve ending fractions. As we previously observed that a similar accumulation of presenilin1, beta-amyloid precursor protein (APP) and APP C-terminal fragment cleaved by beta-secretase in the nerve ending fractions obtained from brains with SPs, the accumulation of intracellular Abeta in this fraction may be closely related to formation of spontaneous SPs with age. Taken together, these results suggest that intensive investigation of age-related changes in the nerve ending will contribute to a better understanding of the pathogenesis of age-related neurodegenerative disorders such as sporadic Alzheimer's disease.

Ninjin-yoei-to (Ren-Shen-Yang-Rong-Tang) and Polygalae radix improves scopolamine-induced impairment of passive avoidance response in mice

We investigated the effect of Ninjin-yoei-to (Ren-Shen-Yang-Rong-Tang), a Japanese herbal medicine, and found that 1000 mg/kg p.o. improved the scopolamine-induced impairment of passive avoidance response in mice. Further, the same dose of Ninjin-yoei-to enhanced oxotremorine-induced tremors in mice. The water extract of Polygalae radix, one of the constituent herbs of Ninjin-yoei-to, at a dose of 100 mg/kg significantly improved the scopolamine-induced impairment of passive avoidance response and enhanced oxotremorine-induced tremors in mice. Moreover, the enhancement of oxotremorine-induced tremors by Ninjin-yoei-to (1000 mg/kg) and Polygalae radix (100 mg/kg) was completely antagonized by pretreatment of scopolamine hydrobromide (0.5 mg/kg). These results suggest that Ninjin-yoei-to may improve the scopolamine-induced impairment of passive avoidance response by enhancing the cholinergic system and that Polygalae radix may be involved in the action of Ninjin-yoei-to.

Comparative efficacy of Keishi-bukuryo-gan and pentoxifylline on RBC deformability in patients with "oketsu" syndrome

Keishi-bukuryo-gan (Gui-Zhi-Fu-Ling-Wan) (KBG) is one of the prescriptions in Japanese traditional medicine for improving the "oketsu" syndrome, so-called blood stasis syndrome. "Oketsu" syndrome is an important pathological conception in Japanese traditional medicine and often accompanies cerebro-vascular disorders. Previously, we were able to reveal a deterioration of RBC (Red blood cell) deformability and viscoelasticity in patients with "oketsu" syndrome. The purpose of the present study was to evaluate whether KBG has an effect on RBC deformability in comparison with pentoxifylline (PXF). The subjects were 30 male patients with multiple lacunar infarctions. Eighteen patients (44-79 yrs, mean +/- SD, 66.1 +/- 10.7 yrs) were treated with 12 g of KBG daily for 4 weeks (KBG group). Twelve patients (59-78 yrs, 70.7 +/- 6.4 yrs) were treated with 300 mg of PXF daily for 4 weeks (PXF group). Based on the "oketsu" score, the patients of each group were divided into two subgroups, a non-"oketsu" group ("oketsu" score 20 points or less) and an "oketsu" group ("oketsu" score 21 points or higher). KBG had significant effects on RBC deformability as evaluated by filtration method. KBG also significantly increased intracellular ATP content, as did PXF. Moreover, KBG was more effective for patients with a more severe "oketsu" state. However, PXF was effective only in patients with "oketsu" syndrome, who might have deteriorated RBC deformability. In conclusion, the effect of KBG on RBC deformability was by no means inferior to PXF.

Inhibitory effects of Choto-san (Diao-teng-san), and hooks and stems of Uncaria sinensis on free radical-induced lysis of rat red blood cells

The present study is designed to test our hypothesis that the ingestion of Uncaria sinensis (US), the main medicinal plant of Choto-san (Diao-teng-san, CS), would protect red blood cell (RBC) membrane from free radical-induced oxidation if polyphenolics in US could be absorbed and circulated in blood. When incubated with RBC suspension, Choto-san extract (CSE) and Uncaria sinensis extract (USE) exhibited strong protection for RBC membrane against hemolysis induced by 2,2-azo-bis (2-amidinopropane) dihydrochloride (AAPH), an azo free-radical initiator. The inhibitory effect was dose-dependent at concentrations of 50 to 1000 microg/mL. Ingestion of 200 mg of USE was associated with a significant decrease in susceptibility of RBC to hemolysis in rats. Furthermore, caffeic acid, an antioxidative hydroxycinnamic acid, was identified in rat plasma after administration of URE.

Reduction of plasma triglyceride level and enhancement of plasma albumin concentration by Oren-gedoku-to administration

Oren-gedoku-to (Huanglian-Jie-Du-Tang, OGT) has been used for the treatment of cerebrovascular disease, hypertension, gastritis and liver disease in Japan. The present study was to test whether ingestion of OGT extract (TJ-15) would affect the metabolism of fatty acids and the usual antioxidant molecule (such as albumin, uric acid and bilirubin) levels in human plasma. After the administration of TJ-15, plasma total cholesterol and the triglyceride level significantly decreased, and lipoprotein lipase mass increased. Significant enhancement of plasma albumin level and reduction of the total plasma protein level resulted in an increment of the albumin/globulin ratio. Plasma fibrinogen, an independent risk factor for cerebrovascular disease, declined considerably, but the reduction was not statistically significant. The findings of this study suggest that ingestion of TJ-15 improves the microcirculation through lipid and protein metabolisms, and is useful for the treatment of cerebral vascular attack in human.

Effect of Seihai-to, a Kampo medicine, in relapsing aspiration pneumonia--an open-label pilot study

Two published case reports described palliation of disease after Seihai-to therapy for refractory aspiration pneumonia caused by recurrent laryngeal nerve paralysis and cerebrovascular disease. We undertook an open-label trial in patients with relapsing aspiration pneumonia. Fifteen patients with relapsing aspiration pneumonia were randomly divided into conventional therapy group (n = 8) or Seihai-to group (n = 7). In Seihai-to group, patients were treated with Seihai-to in addition to conventional therapy (Western medicines). Frequency of feverish days and antibiotics-use, CRP value and chest CT or X-ray findings were compared between the two groups during the study period of 16 weeks. In the Seihai-to group, the latency of swallowing reflex was measured in 6 patients before and after administration of Seihai-to. The mean values of fever index, CRP value and antibiotics-use in the Seihai-to group were decreased significantly, compared with those of the conventional therapy group. However, the latency of the swallowing reflex after 4 weeks of treatment was not significantly changed (p = 0.249), compared with the latency before administration of Seihai-to. No adverse reaction was observed in either group. Seihai-to was effective in reducing relapse of aspiration pneumonia in this small group. Seihai-to might not improve the swallowing reflex, but might instead improve a defense mechanism or excessive inflammation caused by pneumonia in the lower airway. Further evaluation of Seihai-to therapy for patients with aspiration pneumonia in a larger population is warranted.

Age-related changes in the localization of presenilin-1 in cynomolgus monkey brain

Age-related changes in PS-1 localization were examined in the brains of 22 cynomolgus monkeys ranging in age from embryonic day 87 to 35 years. In embryonic monkey brains, anti-PS-1 antibody N12, which recognizes the PS-1 N-terminal fragment (Ntf) and holo protein, stained immature neuronal cells. In juvenile monkeys, N12 stained large pyramidal neurons, cerebral neocortical neurons, and cerebellar Purkinje's cells. Cytoplasmic staining of these cells was granular in appearance. In aged monkeys, N12 stained neurons in all layers of the neocortex. In contrast, regardless of the age of the animals examined, M5, an anti-PS-1 antibody that specifically recognizes only the PS-1 C-terminal fragment (Ctf), stained neurons in all layers of the neocortex and neurons in the cerebellum. M5 also stained neuropil and white matter, and in aged monkeys, M5 stained swollen neurites of mature senile plaques. Age-related changes in PS-1 expression were further examined using Western blot analysis of mitochondrial, myelin, microsomal, nuclear, synaptosomal, and cytosol fractions isolated from 10 monkey brains ranging in age from embryonic day 87 to 32 years. In all brains, Ntf and Ctf were expressed most abundantly in the microsome fraction. The amount of PS-1 in the nuclear fraction dramatically increased with age. We conclude that the transport of PS-1 diminished with age and that PS-1 fragments accumulated in endoplasmic reticulum (ER) associated with the nuclear membrane.

Effects of the extract of the bark of Magnolia obovata and its biphenolic constituents magnolol and honokiol on histamine release from peritoneal mast cells in rats

We have previously reported that saiboku-to, an Oriental herbal remedy composed of a mixture of 10 different herbal extracts, possesses anti-histamine release effect on mast cells in rats. This effect may be due mainly to the extract of the bark of Magnolia obovata (M. obovata), a constituent herb of saiboku-to. In the present study, it was demonstrated that the bark extract inhibited compound 48/80 (C48/80)-induced histamine release from mast cells in a concentration-dependent manner (50 % inhibitory concentration, IC(50) = 56.98 microg/ml). Furthermore, the inhibitory activity was found in the methanol fraction, but not in water and 50 % aqueous methanol fractions derived from the bark extract. Magnolol and honokiol isolated from the methanol fraction inhibited C48/80-induced histamine release from mast cells. The potency of magnolol (IC(50) = 1.04 microg/ml) was greater than that of honokiol (IC(50) = 2.77 microg/ml). Furthermore, the actual amount of magnolol (49.76 +/- 1.14 mg) contained in the bark of M. obovata (5 g) was greater than that (8.58 +/- 0.19 mg) of honokiol. Taken together, the present results suggest that magnolol may be responsible for the biological efficacy of the bark extract of M. obovata.

Protective effect of phenolic compounds isolated from the hooks and stems of Uncaria sinensis on glutamate-induced neuronal death

We isolated the phenolic compounds epicatechin, catechin, procyanidin B-1, procyanidin B-2, hyperin and caffeic acid from the hooks and stems of Uncaria sinensis (HSUS), and studied their protective effects against glutamate-induced neuronal death in cultured rat cerebellar granule cells. Cell viability evaluated by MTT assay was significantly increased by application of epicatechin (100-300 microM), catechin (300 microM), procyanidin B-1 (30-300 microM) and procyanidin B-2 (100-300 microM) compared with exposure to glutamate only. 45Ca2+ influx into cells induced by glutamate was also significantly inhibited by administration ofepicatechin (300 microM), catechin (300 microM), procyanidin B-1 (100-300 microM) and procyanidin B-2 (100-300 microM). These results suggest that epicatechin, catechin, procyanidin B-1 and procyanidin B-2 are the active components of HSUS that protect against glutamate-induced neuronal death in cultured cerebellar granule cells by inhibition of Ca2+ influx.

Effects of Saiko-ka-ryukotsu-borei-to in patients with hyperlipidemia

We measured and compared levels of platelet-derived microparticles (PMPs), monocyte-derived microparticles (MMPs), CD62P on activated platelets, soluble E-selectin (sE-selectin), and anti-oxidized low density lipoprotein (LDL) antibody in hyperlipidemia patients and control subjects. Binding of anti-GPIIb/IIIa and anti-GPIb monoclonal antibodies to platelets was not significantly different between hyperlipidemia patients and controls. However, expression of CD62P on platelets and levels of PMPs were higher for hyperlipidemia patients than in controls, although the difference between groups in CD62P expression was not significant (PMPs: 534 +/- 63 vs. 388 +/- 47, p < 0.05; CD62P: 9.1% +/- 1.45 vs. 7.3% +/- 1.15, N.S.). Although there were no differences in expression of CD36 and CD40 by monocytes between the two groups, levels of MMPs were higher in hyperlipidemia patients than in controls (MMPs: 147 +/- 21 vs. 59 +/- 8, respectively, p < 0.01). Levels of anti-oxidized LDL antibody and sE-selectin were also higher in hyperlipidemia patients. We studied the effects of Saiko-ka-ryukotsu-borei-to on levels of these factors in patients with elevated triglyceride levels. After Saiko-ka-ryukotsu-borei-to treatment, levels of CD62P, PMPs, sE-selectin, and anti-oxidized LDL antibody were reduced significantly. Levels of triglycerides, total cholesterol and MMPs also decreased, but the changes were not significant. These findings suggest that Saiko-ka-ryukotsu-borei-to prevents the development of vascular complications in hyperlipidemia patients.

Vasodilator effect of extract prepared from Uncariae ramulus on isolated rat aorta

Uncariae ramulus et Uncus (URE) has a vasodilator effect. Its mechanism consists of not only endothelium-independent relaxation with Ca2+ channel blocking effect but also endothelium-dependent relaxation with nitric oxide. The active components are alkaloids and tannin contained in Uncariae ramulus et Uncus. They also show a superoxide dismutase-like effect and suppressed vasocontraction induced by xanthine and xanthine oxidase. These mechanisms may also influence vasodilatation by Uncariae ramulus et Uncus in vivo.

Effects of an oriental herbal medicine, "Saiboku-to", and its constituent herbs on Compound 48/80-induced histamine release from peritoneal mast cells in rats

Effects of a traditional oriental herbal medicine, "Saiboku-to" and its constituent herbs on Compound 48/80-induced histamine release from peritoneal mast cells in rats were investigated. Saiboku-to inhibited Compound 48/80-induced degranulation of and histamine release from the mast cells, suggesting that Saiboku-to not only possesses anti-histamine release effect from mast cells, but also contains active herbs with this effect. Significant inhibitions were found in 4 of 10 constituent herbs of Saiboku-to: Magnoliae Cortex, Perillae Herba, Bupleuri Radix and Hoelen. In the dose-response curves of the four herbs, the logarithmic linearity was observed for each herb, and 50% inhibitory concentration, the IC50 values, were calculated to be 56.8 microg/ml for Magnoliae Cortex, 175.8 microl/ml for Perillae Herba, 356.6 microg/ml for Bupleuri Radix, and 595.8 microg/ml for Hoelen. One mg/ml of Saiboku-to showing 75% inhibition of Compound 48/80-induced histamine release level from mast cells contains 88.5 microg of Magnoliae Cortex (it was estimated from the dose-response curve that this dose inhibits 62.68% of the Compound 48/80-induced histamine release level), 58.8 microg of Perillae Herba (21% inhibition), 205.9 microg of Bupleuri Radix (35.24% inhibition), and 147.1 microg of Hoelen (11.15% inhibition). From these results, it is suggested that the anti-histamine release effect of Saiboku-to, which contains 10 herbs, may be due mainly to the effect of Magnoliae Cortex and the synergism of the 3 other herbs.

Squamous cell carcinoma of the oral cavity in an infant cynomolgus monkey

Squamous cell carcinoma was observed in the oral cavity in a one-year-old male cynomolgus monkey. Histopathologically, the tumor consisted of various shaped cells and its assemblies infiltrated into the surrounding connective tissues. Although no obvious metaplastic keratinized cancer pearls were found in the tumor cells, the intercellular bridges were observed. Immunohistochemically, tumor cells were stained with anti-keratin, but not with anti-vimentin. On virological examinations, no papilloma virus antigen or Epstein-Barr Virus small mRNA could not be detected. Under the electron microscope, incomplete tonofibrils and desmosomes in the cytoplasm and microvillus of the cell membrane were observed, suggesting a malignancy or low differentiation of the tumor cells in the present case. This is the first case of squamous cell carcinoma observed in very young macaques, to our knowledge.

Tagged mutagenesis and gene-trap in the moss, Physcomitrella patens by shuttle mutagenesis

The moss, Physcomitrella patens has been used as a useful material in many fields, because of its simple body plan, ease of gene targeting, and other reasons. Although many mutants have been reported, no method to isolate the corresponding genes was reported. We developed a gene tagging and gene-trap system in P. patens by using the shuttle mutagenesis technique, which has been used in the budding yeast. In 5264 tagged lines, 203 mutants with altered developmental or morphological phenotypes were obtained. In 129 of 4757 gene-trap lines, beta-glucuronidase (GUS) activity was detected in some tissue. Although multiple copies of a tag were detected in many tagged lines by Southern analyses, most copies are likely integrated at the same locus according to PCR analyses.

Effect of Hochu-ekki-to (TJ-41), a Japanese herbal medicine, on the survival of mice infected with influenza virus

The antiviral effect of Hochu-ekki-to (TJ-41), a Japanese herbal medicine, was investigated using mice infected with influenza virus. TJ-41 was found to increase the survival rate, prolong the mean survival days, suppress viral growth in bronchoalveolar labage fluid (BALF) and inhibit the lung index (lung consolidation) on day 4 after infection in mice infected with influenza, after the agent had been administered orally once daily from day 7 to 2 before infection and from day 0 to 4 after infection. Administration of TJ-41 decreased the BALF concentrations of IL-1alpha, IL-6 and GM-CSF, but not TNF-alpha or interferon-gamma (IFN-gamma), on day 4 after infection. In addition, TJ-41 elevated the level of IFN-alpha in BALF on day 2 after infection. Yet, TJ-41 did not show any inhibitory effect on the growth of influenza virus in vitro. These results suggest that TJ-41 exerts its inhibitory effect on influenza virus infection via enhancement of the host immune responses in this experimental murine system.

Effect on locomotion of indole alkaloids from the hooks of uncaria plants

Three predominant Uncariae plants, Uncaria rhynchophylla U. sinensis and U. macrophylla and their indole and oxindole alkaloid constituents were studied for their effect on locomotor response. Water extracts of U. macrophylla and U. sinensis and four indole alkaloids, corynoxine, corynoxine B, isorhynchophylline and geissoschizine methyl ether, significantly decreased locomotor activity after oral administration to mice. The depression of locomotor activity upon administration of these alkaloids appears to be due to mediating of the central dopaminergic system.

Evaluation of the protective effects of alkaloids isolated from the hooks and stems of Uncaria sinensis on glutamate-induced neuronal death in cultured cerebellar granule cells from rats

We have previously shown that an aqueous extract of the hooks and stems of Uncaria sinensis (Oliv.) Havil., Uncariae Uncus Cum Ramulusis, protects against glutamate-induced neuronal death in cultured cerebellar granule cells by inhibition of Ca2+ influx. Because it is not known which components of Uncaria sinensis are active, in this study we have evaluated, by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) staining, the neuroprotective effects of the oxyindole alkaloids corynoxeine, rhynchophylline, isorhynchophylline and isocorynoxeine, and the indole alkaloids geissoschizine methyl ether, hirsuteine and hirsutine, isolated from the hooks and stems of Uncaria sinensis, on glutamate-induced cell death. We also investigated the inhibitory effects of the compounds on 45Ca2+ influx in cultured rat cerebellar granule cells. Cell viability evaluated by the MTT assay was significantly increased by application of rhynchophylline (10(-3) M), isorhynchophylline (10(-4)-10(-3) M), isocorynoxeine (10(-4)-10(-3) M), hirsuteine (10(-4)-3 x 10(-4) M) or hirsutine (10(-4)-3 x 10(-4) M) compared with exposure to glutamate only, with the effect of isorhynchophylline being the strongest. The increased 45Ca2+ influx into cells induced by glutamate was significantly inhibited by administration of rhynchophylline (10(-3) M), isorhynchophylline (3 x 10(-4)-10(-3) M), isocorynoxeine (3 x 10(-4)-10(-3) M), geissoschizine methyl ether (10(-3) M), hirsuteine (3 x 10(-4)-10(-3) M) or hirsutine (3 x 10(-4)-10(-3) M). These results suggest that oxyindole alkaloids such as isorhynchophylline, isocorynoxeine and rhynchophylline and indole alkaloids such as hirsuteine and hirsutine are the active components of the hooks and stems of Uncaria sinensis which protect against glutamate-induced neuronal death in cultured cerebellar granule cells by inhibition of Ca2+ influx.

First isolation of Sarcocystis hominis from cattle in Japan

Sarcocystis hominis was first isolated from slaughtered cattle raised in Japan. Cysts were 1,220-4,460 x 80-384 microns in size and their wall was 3 to 6 microns thick and appeared radially striated in the histopathological sections because of the presence of palisade-like villar protrusions on the surface. The protrusions were 3.1-4.3 x 0.7-1.1 microns in size and had many microtubules in the core. Two cynomolgus monkeys, Macaca fascicularis, fed with the Sarcocystis cysts began to pass sporocysts, which measured a size of 14.3-15 x 9.5-10 microns, in the feces 10 days after ingestion.

Quantitative analysis of aristolochic acids, toxic compounds, contained in some medicinal plants

The amounts of aristolochic acid I and II in four groups of medicinal plants from the Aristolochiaceae and some related plants were determined by high-pressure liquid chromatography, for Aristolochia was reported to produce interstitial nephritis caused by aristolochic acids during chronic use for the treatment of rheumatism, diuretic and analgesic. They were detected in all the plants that originated from the genus Aristolochia (Aristolochiaceae) and in some of the plants from the genus Asarum (Aristolochiaceae). The present results suggest that these medicinal plants should be prohibited to use for remedy due to the harmful effects attributed to aristolochic acids.

Opportunistic Pneumocystis carinii infection in red-bellied tamarins (Saguinus labiatus)

P. carinii infection in red-bellied tamarins (Saguinus labiatus), born and maintained in a laboratory breeding colony, was examined by histopathologic examination postmortem. P. carinii cysts were detected in 6 of 10 red-bellied tamarins examined, by using Grocott's, toluidine blue O and immunostaining with avidin-biotin complex using antisera for rat-, simian-, and human-P. carinii. The results obtained from the present studies imply that P. carinii may be an important pathogen in this species.

Effects of Sho-saiko-to, San'o-shashin-to and Scutellariae Radix on intracellular Ca2+ mobilization in C6 rat glioma cells

Glial cells are able to support neurons physically and functionally. The present study was undertaken to determine the effects of Kampo medicines on glial cell function, especially Ca2+ mobilization. C6 rat glioma cells expressed H1-histamine, muscarinic cholinergic and adrenergic alpha1-receptors, stimulation of which resulted in phosphoinositide hydrolysis and increase in intracellular Ca2+ concentrations ([Ca2+]i). The water extracts of Sho-saiko-to and San'o-shashin-to, Kampo medicines which contain Scutellariae Radix (Ogon, the root of Scutellaria baicalensis GFORGI), inhibited histamine (100 microM)-induced increase in [Ca2+]i in a concentration-dependent manner. The water extract of Scutellariae Radix potently decreased [Ca2+]i in a concentration-dependent manner. Sho-saiko-to, San'o-shashin-to and Scutellariae Radix significantly inhibited histamine-induced accumulation of total [3H]inositol phosphates, consistent with their inhibition of the increase in [Ca2+1]i. These results suggest that Sho-saiko-to, San'o-shashin-to and Scutellariae Radix inhibit Ca2+ mobilization mediated via an inhibition of phospholipase C. The inhibitory effect may be important in interpreting the pharmacological actions of above Kampo medicines.

Histopathological studies of senile plaques and cerebral amyloidosis in cynomolgus monkeys

Senile plaques (SPs) and cerebral amyloid angiopathy (CAA), pathological hallmarks of Alzheimer's disease, have not been thoroughly investigated histopathologically in nonhuman primates. To determine the onset age and histopathological characteristics of SPs and CAA, we examined the brains of 64 cynomolgus monkeys (Macaca fascicularis) from 2 to 35 years old. Mature (classical and primitive) plaques appeared in 16 out of 25 monkeys that were >20 years old. Moreover, mature plaques were observed more frequently than diffuse plaques and were located in the temporal cortex of the superior or inferior gyri and amygdala. Diffuse plaques in contrast to mature plaques did not show definite tendencies in onset age and distribution. CAA appeared in more than 22-year-old monkeys in 10 out of 16 animals and was frequently observed in capillaries and often found adjoining mature plaques. During immunohistochemical examination, an antiserum for amyloid beta protein (A beta) 1-40 could detect all SPs, whereas a monoclonal antibody for A beta 8-17 could not detect any diffuse plaques and only one third of the primitive plaques. As for CAA, the polyclonal antiserum was more sensitive than the monoclonal antibody. The present study describes the histopathological features of SPs and CAA in old cynomolgus monkeys.

Baicalin and baicalein, constituents of an important medicinal plant, inhibit intracellular Ca2+ elevation by reducing phospholipase C activity in C6 rat glioma cells

Glial cells have a role in maintaining the function of neural cells. This study was undertaken to clarify the effects of baicalin and baicalein, flavonoids isolated from an important medicinal plant Scutellariae Radix (the root of Scutellaria baicalensis Georgi), on glial cell function using C6 rat glioma cells. Baicalin and baicalein caused concentration-dependent inhibition of a histamine-induced increase in intracellular Ca2+ concentrations ([Ca2+]i). The potency of baicalein was significantly greater than that of baicalin. The noradrenaline- and carbachol-induced increase in [Ca2+]i was also inhibited by baicalein and both drugs inhibited histamine-induced accumulation of total [3H]inositol phosphates, consistent with their inhibition of the increase in [Ca2+]i. These results suggest that baicalin and baicalein inhibit [Ca2+]i elevation by reducing phospholipase C activity. The inhibitory effects of baicalin and baicalein on [Ca2+]i elevation might be important in the interpretation of their pharmacological action on glial cells, such as inhibition of Ca2(+)-required enzyme phospholipase A2.

Simian T cell leukemia virus type I-induced malignant adult T cell leukemia-like disease in a naturally infected African green monkey: implication of CD8+ T cell leukemia

Spontaneous T cell leukemia was found in an African green monkey (Cercopithecus aethiops, AGM) naturally infected with simian T cell leukemia virus type I (STLV-I). The hematological features and the evidence for monoclonal integration of provirus DNA in the leukemic cells revealed that the leukemia was an ATL-like disease. The expression of surface markers on the leukemic cells indicated that they were defined as an activated CD8+ T cell subset. Together with the finding that seven in vitro spontaneously STLV-I-transformed cell lines were CD4-CD8+, it is likely that CD8+ T cells are transformed by STLV-I in AGMs, in contrast with human ATL. Finally, we assessed characteristics of the CD8 chains on these transformed cells. The result indicated that the leukemic cells expressed only the alpha chains but not the beta chains. However, in the case of in vitro-transformed cell lines the expression pattern of the CD8 chains varied in individual monkeys. Thus, STLV-I may preferentially transform CD8+ (both alphaalpha+ and alphabeta+) T cells in AGMs.

Immunohistochemical characteristics of the constituents of senile plaques and amyloid angiopathy in aged cynomolgus monkeys

In this study, we immunohistochemically examined the several constituents of senile plaques (SPs) and cerebral amyloid angiopathy (CAA) in aged cynomolgus monkeys. Apolipoprotein E (apoE) deposited in all mature plaques and CAA, and in half of the diffuse plaques. Alpha-1-antichymotripsin (alpha ACT) deposited in half of the mature plaques and in one third of the CAA. Amyloid precursor protein (APP), ubiquitin (Ub), and microtubule-associated protein-2 (MAP-2) accumulated in the swollen neurites of mature plaques. Glial fibrillary acidic protein (GFAP) was detected in the astrocytes and their processes surrounding the mature plaques. Tau was detected in neither the SPs nor CAA. Therefore, mature plaques involved extracellular A beta, apoE, and alpha ACT, and also astrocytes and swollen neurites. However, diffuse plaques involved only extracellular A beta and apoE. Since these features, except for tau, were consistent with those in humans, this animal model will be useful for studying the pathogenesis of cerebral amyloid deposition.

Immunohistochemical study on the deposition of apolipoprotein E in cerebral and islet amyloidoses in cynomolgus monkeys (Macaca fascicularis)

To investigate the role of apolipoprotein E (apo E) in amyloidoses of cynomolgus monkeys, the localization of apo E in cerebral amyloid, including senile plaques and cerebrovascular amyloid, and in islet amyloid was examined immunohistochemically. Mature types of senile plaques with amyloid deposits and cerebrovascular amyloid showed intense immunoreactivity to both antisera to apo E and amyloid beta protein (A beta). In contrast, diffuse plaques without obvious Congophilic amyloid showed weak immunoreactivity to antiserum to apo E, but intense reactivity to antiserum to A beta. In addition, the number of these apo E-positive diffuse plaques was small compared with that of A beta-positive plaques. On the other hand, diabetic islet amyloid that was negative with A beta, reacted intensely with antiserum to apo E. These findings suggest that apo E plays an important role in amyloid fibril formation in several types of amyloidoses.