Visualization of Amyloid Oligomers in the Brain of Patients with Alzheimer's Disease

In the pathogenesis of Alzheimer's disease (AD), highly neurotoxic amyloid-β (Aβ) oligomers appear early, they are thus considered to be deeply involved in the onset of Alzheimer's disease. However, Aβ oligomer visualization is challenging in human tissues due to their multiple forms (e.g., low- and high-molecular-weight oligomers, including protofibrils) as well as their tendency to rapidly change forms and aggregate. In this review, we present two visualization approaches for Aβ oligomers in tissues: an immunohistochemical (using the monoclonal antibody TxCo1 against toxic Aβ oligomer conformers) and imaging mass spectrometry using the small chemical Shiga-Y51 that specifically binds Aβ oligomers. TxCo1 immunohistochemistry revealed Aβ oligomer distributions in postmortem human brains with AD. Using Shiga-Y51, imaging mass spectrometry revealed Aβ oligomer distributions in the brain of a transgenic mouse model for AD. These two methods would potentially contribute to elucidating the pathological mechanisms underlying AD.

OLIG2 is an in vivo bookmarking transcription factor in the developing neural tube in mouse

Cells possess intrinsic features that are inheritable via epigenetic regulation, such as DNA methylation and histone modification. These inheritable features maintain a unique gene expression pattern, underlying cellular memory. Because of the degradation or displacement of mitotic chromosomes, most transcription factors do not contribute to cellular memory. However, accumulating in vitro evidence indicates that some transcription factors can be retained in mitotic chromosomes called as bookmarking. Such transcription factors may contribute to a novel third mechanism of cellular memory. Since most findings of transcription factor bookmarking have been reported in vitro, little is currently known in vivo. In the neural tube of mouse embryos, we discovered that OLIG2, a basic helix loop helix (bHLH) transcription factor that regulates proliferation of neural progenitors and the cell fate of motoneurons and oligodendrocytes, binds to chromatin through every cell cycle including M-phase. OLIG2 chromosomal localization coincides with mitotic cell features such as the phosphorylation of histone H3, KI67, and nuclear membrane breakdown. Chromosomal localization of OLIG2 is regulated by an N-terminus triple serine motif. Photobleaching analysis revealed slow OLIG2 mobility, suggesting a high affinity of OLIG2 to DNA. In Olig2 N-terminal deletion mutant mice, motoneurons and oligodendrocyte progenitor numbers are reduced in the neural tube, suggesting that the bookmarking regulatory domain is important for OLIG2 function. We conclude that OLIG2 is a de novo in vivo bookmarking transcription factor. Our results demonstrate the presence of in vivo bookmarking in a living organism and illustrate a novel function of transcription factors.

Establishment of neural stem cell culture from the central nervous system of the Iberian ribbed newt Pleurodeles waltl

Urodele amphibians have exceptional regeneration ability in various organs. Among these, the Iberian ribbed newt (Pleurodeles waltl) has emerged as a useful model organism for investigating the mechanisms underlying regeneration. Neural stem cells (NSCs) are an important source of regeneration in the central nervous system (CNS) and their culture method in vitro has been well established. NSCs form spherical cell aggregates called neurospheres and their formation has been demonstrated in various vertebrates, including some urodele species, but not in P. waltl. In this study, we reported neurosphere formation in brain- and spinal cord-derived cells of post-metamorphic P. waltl. These neurospheres showed proliferative activity and similar expression of marker proteins. However, the surface morphology was found to vary according to their origin, implying that the characteristics of the neurospheres generated from the brain and spinal cord could be similar but not identical. Subsequent in vitro differentiation analysis demonstrated that spinal cord-derived neurospheres gave rise to neurons and glial cells. We also found that cells in neurospheres from P. waltl differentiated to oligodendrocytes, whereas those from axolotls were reported not to differentiate to this cell type under standard culture conditions. Based on our findings, implantation of genetically modified neurospheres together with associated technical advantages in P. waltl could reveal pivotal gene(s) and/or signaling pathway(s) essential for the complete spinal cord regeneration ability in the future.

Cytoplasmic Polyadenylation Element-Binding Protein 1 Post-transcriptionally Regulates Fragile X Mental Retardation 1 Expression Through 3′ Untranslated Region in Central Nervous System Neurons

Fragile X syndrome (FXS) is an inherited intellectual disability caused by a deficiency in Fragile X mental retardation 1 (Fmr1) gene expression. Recent studies have proposed the importance of cytoplasmic polyadenylation element-binding protein 1 (CPEB1) in FXS pathology; however, the molecular interaction between Fmr1 mRNA and CPEB1 has not been fully investigated. Here, we revealed that CPEB1 co-localized and interacted with Fmr1 mRNA in hippocampal and cerebellar neurons and culture cells. Furthermore, CPEB1 knockdown upregulated Fmr1 mRNA and protein levels and caused aberrant localization of Fragile X mental retardation protein in neurons. In an FXS cell model, CPEB1 knockdown upregulated the mRNA levels of several mitochondria-related genes and rescued the intracellular heat shock protein family A member 9 distribution. These findings suggest that CPEB1 post-transcriptionally regulated Fmr1 expression through the 3′ untranslated region, and that CPEB1 knockdown might affect mitochondrial function.

Sulfatide with ceramide composed of phytosphingosine (t18:0) and 2-hydroxy fatty acids in renal intercalated cells

Diverse molecular species of sulfatide with differences in FA lengths, unsaturation degrees, and hydroxylation statuses are expressed in the kidneys. However, the physiological functions of specific sulfatide species in the kidneys are unclear. Here, we evaluated the distribution of specific sulfatide species in the kidneys and their physiological functions. Electron microscopic analysis of kidneys of Cst-deficient mice lacking sulfatide showed vacuolar accumulation in the cytoplasm of intercalated cells in the collecting duct, whereas the proximal and distal tubules were unchanged. Immunohistochemical analysis revealed that vacuolar H⁺-ATPase-positive vesicles were accumulated in intercalated cells in sulfatide-deficient kidneys. Seventeen sulfatide species were detected in the murine kidney by iMScope MALDI-MS analysis. The distribution of the specific sulfatide species was classified into four patterns. Although most sulfatide species were highly expressed in the outer medullary layer, two unique sulfatide species of m/z 896.6 (predicted ceramide structure: t18:0-C22:0h) and m/z 924.6 (predicted ceramide structure: t18:0-C24:0h) were dispersed along the collecting duct, implying expression in intercalated cells. In addition, the intercalated cell-enriched fraction was purified by fluorescence-activated cell sorting using the anti-vacuolar H⁺-ATPase subunit 6V0A4, which predominantly contained sulfatide species (m/z 896.6 and 924.6). The Degs2 and Fa2h genes, which are responsible for ceramide hydroxylation, were expressed in the purified intercalated cells. These results suggested that sulfatide molecular species with ceramide composed of phytosphingosine (t18:0) and 2-hydroxy FAs, which were characteristically expressed in intercalated cells, were involved in the excretion of NH₃ and protons into the urine.

Cpeb1 expression is post-transcriptionally regulated by AUF1, CPEB1, and microRNAs

Cytoplasmic polyadenylation element binding protein 1 (CPEB1) regulates the translation of numerous mRNAs. We previously showed that AU‐rich binding factor 1 (AUF1) regulates Cpeb1 expression through the 3’ untranslated region (3’UTR). To investigate the molecular basis of the regulatory potential of the Cpeb1 3’UTR, here we performed reporter analyses that examined expression levels of Gfp reporter mRNA containing the Cpeb1 3’UTR. Our findings indicate that CPEB1 represses the translation of Cpeb1 mRNA and that miR‐145a‐5p and let‐7b‐5p are involved in the reduction in Cpeb1 expression in the absence of AUF1. These results suggest that Cpeb1 expression is post‐transcriptionally regulated by AUF1, CPEB1, and microRNAs.

Keto form of curcumin derivatives strongly binds to Aβ oligomers but not fibrils

The accumulation of β-amyloid (Aβ) aggregates in the brain occurs early in the progression of Alzheimer's disease (AD), and non-fibrillar soluble Aβ oligomers are particularly neurotoxic. During binding to Aβ fibrils, curcumin, which can exist in an equilibrium state between its keto and enol tautomers, exists predominantly in the enol form, and binding activity of the keto form to Aβ fibrils is much weaker. Here we described the strong binding activity the keto form of curcumin derivative Shiga-Y51 shows for Aβ oligomers and its scant affinity for Aβ fibrils. Furthermore, with imaging mass spectrometry we revealed the blood-brain barrier permeability of Shiga-Y51 and its accumulation in the cerebral cortex and the hippocampus, where Aβ oligomers were mainly localized, in a mouse model of AD. The keto form of curcumin derivatives like Shiga-Y51 could be promising seed compounds to develop imaging probes and therapeutic agents targeting Aβ oligomers in the brain.

AUF1, an mRNA decay factor, has a discordant role in Cpeb1 expression

Cytoplasmic polyadenylation element binding protein 1 (CPEB1) regulates polyadenylation and subsequent translation of CPE-containing mRNAs involved in various physiological and pathological phenomena. Although the significance of CPEB1-mediated translational regulation has recently been reported, the detailed regulatory mechanism of Cpeb1 expression remains unclear. To elucidate the post-transcriptional regulatory mechanisms of Cpeb1 expression, we constructed reporter plasmids containing various deletions or mutations in the Cpeb1 mRNA 3' untranslated region (3'UTR). We investigated their expression levels in Neuro2a neuroblastoma cells. We found that Cpeb1 expression is regulated through an AU-rich element in its 3'UTR. Furthermore, the mRNA decay factor AU-rich binding factor 1 (AUF1) regulates Cpeb1 expression, and knockdown of AUF1 upregulates Cpeb1 mRNA expression but results in a decrease in CPEB1 protein levels. These findings indicate that AUF1 has a discordant role in the expression of Cpeb1.

Change in phospholipid species of retinal layer in traumatic optic neuropathy model

Injured optic nerves induce death in almost all retinal ganglion cells (RGC) and cause a loss of axons. To date, we have studied injured RGC axon regeneration by using a traumatic optic nerve injury (TONI) rodent model, and we revealed that axonal regeneration is induced by the graft of an autologous peripheral nerve. The efficient approach to the regeneration of axons thus needs an environmental adjustment of RGC. However, the RGC environment induced by TONI remains unknown. Here, we analyzed female and male C57BL/6 mouse retinal tissue alterations in detail after TONI and focused on the major phospholipid species that are enriched in the whole retina. Reactive astrocyte accumulation, glia scar formation, and demyelination were observed in the injured optic nerve area, while RGC cell death, astrocyte accumulation, and Glial fibrillary acidic protein (GFAP) positive Müller cell increases were detected in the retinal layer. Furthermore, phosphatidylinositol (PI) 18:0/20:4 was localized to three nuclear layer structures: the ganglion cell layer (GCL), the inner nuclear layer (INL), and the outer nuclear layer (ONL) in control retina; however, the localization of 18:0/20:4 PI in TONI was disturbed. Meanwhile, phosphatidylserine (PS) 18:0/22:6 showed that the expression was specifically in the inner plexiform layer (IPL) with similar signal intensity in both cases. Other PS species and phosphatidylethanolamine (PE) were differentially localized in the retinal layer; however, the expressions of PE including docosahexaenoic acid (DHA) were affected by TONI. These results suggest that not only GCL but also other retinal layers were influenced by TONI.

Involvement of PLAGL1/ZAC1 in hypocretin/orexin transcription

The hypocretin/orexin neuropeptide system coordinates the regulation of various physiological processes. Our previous study reported that a reduction in the expression of pleomorphic adenoma gene-like 1 (Plagl1), which encodes a C2H2 zinc-finger transcription factor, occurs in hypocretin neuron-ablated transgenic mice, suggesting that PLAGL1 is co-expressed in hypocretin neurons and regulates hypocretin transcription. The present study examined whether canonical prepro-hypocretin transcription is functionally modulated by PLAGL1. Double immunostaining indicated that the majority of hypocretin neurons were positive for PLAGL1 immunore-activity in the nucleus. Notably, PLAGL1 immunoreactivity in hypocretin neurons was altered in response to several conditions affecting hypocretin function. An uneven localization of PLAGL1 was detected in the nuclei of hypocretin neurons following sleep deprivation. Chromatin immunoprecipitation revealed that endogenous PLAGL1 may bind to a putative PLAGL1-binding site in the proximal region of the hypocretin gene, in the murine hypothalamus. In addition, electroporation of the PLAGL1 expression vector into the fetal hypothalamus promoted hypothalamic hypocretin transcription. These results suggested that PLAGL1 may regulate hypothalamic hypocretin transcription.

Differential expression of nuclear lamin subtypes in the neural cells of the adult rat cerebral cortex

Lamins are type V intermediate filament proteins that are located beneath the inner nuclear membrane. In mammalian somatic cells, LMNB1 and LMNB2 encode somatic lamins B1 and B2, respectively, and the LMNA gene is alternatively spliced to generate somatic lamins A and C. Mutations in lamin genes have been linked to many human hereditary diseases, including neurodegenerative disorders. Knowledge about lamins in the nervous system has been accumulated recently, but a precise analysis of lamin subtypes in glial cells has not yet been reported. In this study we investigated the composition of lamin subtypes in neurons, astrocytes, oligodendrocyte-lineage cells, and microglia in the adult rat cerebral cortex using an immunohistochemical staining method. Lamin A was not observed in neurons and glial cells. Lamin C was observed in astrocytes, mature oligodendrocytes and neurons, but not observed in oligodendrocyte progenitor cells. Microglia also did not stain positive for lamin C which differed from macrophages, with lamin C positive. Lamin B1 and B2 were observed in all glial cells and neurons. Lamin B1 was intensely positive in oligodendrocyte progenitor cells compared with other glial cells and neurons. Lamin B2 was weakly positive in all glial cells compared to neurons. Our current study might provide useful information to reveal how the onset mechanisms of human neurodegenerative diseases are associated with mutations in genes for nuclear lamin proteins.

Involvement of DHH and GLI1 in adrenocortical autograft regeneration in rats

Bilateral adrenalectomy forces the patient to undergo glucocorticoid replacement therapy and bear a lifetime risk of adrenal crisis. Adrenal autotransplantation is considered useful to avoid adrenal crisis and glucocorticoid replacement therapy. However, the basic process of regeneration in adrenal autografts is poorly understood. Here, we investigated the essential regeneration factors in rat adrenocortical autografts, with a focus on the factors involved in adrenal development and steroidogenesis, such as Hh signalling. A remarkable renewal in cell proliferation and increase in Cyp11b1, which encodes 11-beta-hydroxylase, occurred in adrenocortical autografts from 2-3 weeks after autotransplantation. Serum corticosterone and adrenocorticotropic hormone levels were almost recovered to sham level at 4 weeks after autotransplantation. The adrenocortical autografts showed increased Dhh expression at 3 weeks after autotransplantation, but not Shh, which is the only Hh family member to have been reported to be expressed in the adrenal gland. Increased Gli1 expression was also found in the regenerated capsule at 3 weeks after autotransplantation. Dhh and Gli1 might function in concert to regenerate adrenocortical autografts. This is the first report to clearly show Dhh expression and its elevation in the adrenal gland.

Origin of Oligodendrocytes in the Vertebrate Optic Nerve: A Review

One of the unsolved problems in the research field of oligodendrocyte (OL) development has been the site(s) of origin of optic nerve OLs and its precursor cells (OPCs). It is generally accepted that OLs in the optic nerve are derived from the brain, and thus optic nerve OLs are immigrant cells. We previously demonstrated the brain origin of optic nerve OPCs in chick embryos. However, the site of optic nerve OPC origin has not been examined experimentally in developing rodents for the past two decades. We have recently reported that optic nerve OPCs in mice arise in the preoptic area by E12.5 and gradually migrate caudally and enter the optic nerve. These OPCs give rise to myelinating OLs in the optic nerve in the postnatal or adult stages. Surprisingly, there are species differences with respect to the origin of optic nerve OPCs between chicks and mice. Here, we summarize the site of OPC origin in the optic nerve based on our own previous and recent results, and discuss possible mechanisms underlying these species differences.

Sulfatide species with various fatty acid chains in oligodendrocytes at different developmental stages determined by imaging mass spectrometry

HSO3-3-galactosylceramide (Sulfatide) species comprise the major glycosphingolipid components of oligodendrocytes and myelin and play functional roles in the regulation of oligodendrocyte maturation and myelin formation. Although various sulfatide species contain different fatty acids, it is unclear how these sulfatide species affect oligodendrogenesis and myelination. The O4 monoclonal antibody reaction with sulfatide has been widely used as a useful marker for oligodendrocytes and myelin. However, sulfatide synthesis during the pro-oligodendroblast stage, where differentiation into the oligodendrocyte lineage has already occurred, has not been examined. Notably, this stage comprises O4-positive cells. In this study, we identified a sulfatide species from the pro-oligodendroblast-to-myelination stage by imaging mass spectrometry. The results demonstrated that short-chain sulfatides with 16 carbon non-hydroxylated fatty acids (C16) and 18 carbon non-hydroxylated fatty acids (C18) or 18 carbon hydroxylated fatty acids (C18-OH) existed in restricted regions of the early embryonic spinal cord, where pro-oligodendroblasts initially appear, and co-localized with Olig2-positive pro-oligodendroblasts. C18 and C18-OH sulfatides also existed in isolated pro-oligodendroblasts. C22-OH sulfatide became predominant later in oligodendrocyte development and the longer C24 sulfatide was predominant in the adult brain. Additionally, the presence of each sulfatide species in a different area of the adult brain was demonstrated by imaging mass spectrometry at an increased lateral resolution. These findings indicated that O4 recognized sulfatides with short-chain fatty acids in pro-oligodendroblasts. Moreover, the fatty acid chain of the sulfatide became longer as the oligodendrocyte matured. Therefore, individual sulfatide species may have unique roles in oligodendrocyte maturation and myelination. Read the Editorial Highlight for this article on page 356.

Sox2 promotes survival of satellite glial cells in vitro

Sox2 is a transcriptional factor expressed in neural stem cells. It is known that Sox2 regulates cell differentiation, proliferation and survival of the neural stem cells. Our previous study showed that Sox2 is expressed in all satellite glial cells of the adult rat dorsal root ganglion. In this study, to examine the role of Sox2 in satellite glial cells, we establish a satellite glial cell-enriched culture system. Our culture method succeeded in harvesting satellite glial cells with the somata of neurons in the dorsal root ganglion. Using this culture system, Sox2 was downregulated by siRNA against Sox2. The knockdown of Sox2 downregulated ErbB2 and ErbB3 mRNA at 2 and 4 days after siRNA treatment. MAPK phosphorylation, downstream of ErbB, was also inhibited by Sox2 knockdown. Because ErbB2 and ErbB3 are receptors that support the survival of glial cells in the peripheral nervous system, apoptotic cells were also counted. TUNEL-positive cells increased at 5 days after siRNA treatment. These results suggest that Sox2 promotes satellite glial cell survival through the MAPK pathway via ErbB receptors.

Sox2 in the adult rat sensory nervous system

Sex-determining region Y (SRY)-box 2 (Sox2) is a member of the Sox family transcription factors. In the central nervous system, Sox2 is expressed in neural stem cells from neurogenic regions, and regulates stem cell proliferation and differentiation. In the peripheral nervous system, Sox2 is found only in the immature and dedifferentiated Schwann cells, and is involved in myelination inhibition or N-cadherin redistribution. In the present immunohistochemical study, we found that Sox2 is also expressed in other cells of the adult rat peripheral nervous system. Nuclear Sox2 was observed in all satellite glial cells, non-myelinating Schwann cells, and the majority of terminal Schwann cells that form lamellar corpuscles and longitudinal lanceolate endings. Sox2 was not found in myelinating Schwann cells and terminal Schwann cells of subepidermal free nerve endings. Satellite glial cells exhibit strong Sox2 immunoreactivity, whereas non-myelinating Schwann cells show weak immunoreactivity. RT-PCR confirmed the presence of Sox2 mRNA, indicating that the cells are likely Sox2 expressors. Our findings suggest that the role of Sox2 in the peripheral nervous system may be cell-type-dependent.

17β-Estradiol and 17α-estradiol induce rapid changes in cytoskeletal organization in cultured oligodendrocytes

Dramatic changes in the cytoskeleton and the morphology of oligodendrocytes (OLs) occur during various stages of the myelination process. OLs in culture produce large membrane sheets containing cytoskeletal veins of microtubules and actin filaments. We recently showed that estrogen receptors (ER) related to ERα/β were expressed in the membrane sheets of mature OLs in culture. Ligation of these or other membrane ERs in OLs with both 17β- and 17α-estradiol mediated rapid non-genomic signaling. Here, we show that estrogens also mediate rapid non-genomic remodeling of the cytoskeleton in mature OLs in culture. 17β-Estradiol caused a rapid loss of microtubules and the actin cytoskeleton in the OL membrane sheets. It also increased phosphorylation of the actin filament-severing protein cofilin, thus inactivating it. Staining for actin barbed ends with rhodamine-actin showed that it decreased the amount of actin barbed ends. 17α-Estradiol, on the other hand, increased the percentage of cells with abundant staining of actin filaments and actin barbed ends, suggesting that it stabilized and/or increased the dynamics of the actin cytoskeleton. The specific ERα and ERβ agonists, 4,4',4″-(4-propyl-(1H)-pyrazole-1,3,5-triyl) trisphenol (PPT) and diarylpropionitrile 2,3-bis(4-hydroxy-phenyl)-propionitrile (DPN), respectively, also caused the rapid phosphorylation of cofilin. Estrogen-induced phosphorylation of cofilin was inhibited by Y-27632, a specific inhibitor of the Rho-associated protein serine/threonine kinase (ROCK). The Rho/ROCK/cofilin pathway is therefore implicated in actin rearrangement via estrogen ligation of membrane ERs, which may include forms of ERα and ERβ. These results indicate a role for estrogens in modulation of the cytoskeleton in mature OLs, and thus in various processes required for myelinogenesis.

G protein-coupled receptor 30 contributes to improved remyelination after cuprizone-induced demyelination

Estrogen exerts neuroprotective and promyelinating actions. The therapeutic effect has been shown in animal models of multiple sclerosis, in which the myelin sheath is specifically destroyed in the central nervous system. However, it remains unproven whether estrogen is directly involved in remyelination via the myelin producing cells, oligodendrocytes, or which estrogen receptors are involved. In this study, we found that the membrane-associated estrogen receptor, the G protein-coupled receptor 30 (GPR30), also known as GPER, was expressed in oligodendrocytes in rat spinal cord and corpus callosum. Moreover, GPR30 was expressed throughout oligodendrocyte differentiation and promyelinating stages in primary oligodendrocyte cultures derived from rat spinal cords and brains. To evaluate the role of signaling via GPR30 in promyelination, a specific agonist for GPR30, G1, was administered to a rat model of demyelination induced by cuprizone treatment. Histological examination of the corpus callosum with oligodendrocyte differentiation stage-specific markers showed that G1 enhanced oligodendrocyte maturation in corpus callosum of cuprizone-treated animals. It also enhanced oligodendrocyte ensheathment of dorsal root ganglion (DRG) neurons in co-culture and myelination in cuprizone-treated animals. This study is the first evidence that GPR30 signaling promotes remyelination by oligodendrocytes after demyelination. GPR30 ligands may provide a novel therapy for the treatment of multiple sclerosis.

Differential responses of endogenous adult mouse neural precursors to excess neuronal excitation

Adult neurogenesis in the subgranular zone of the hippocampus (SGZ) is enhanced by excess as well as mild neuronal excitation, such as chemoconvulsant-induced brief seizures. Because most studies of neurogenesis after seizures have focused on the SGZ, the threshold of neuronal excitation required to enhance neurogenesis in the subventricular zone (SVZ) is not clear. Therefore, we examined the responses of SVZ precursors to brief generalized clonic seizures induced by a single administration of the chemoconvulsant pentylenetetrazole (PTZ). Cell cycle progression of precursors was analysed by systemic administration of thymidine analogues. We found that brief seizures immediately resulted in cell cycle retardation in the SVZ. However, the same effect was not seen in the SGZ. This initial cell cycle retardation in the SVZ was followed by enhanced cell cycle re-entry after the first round of mitosis, leading to precursor pool expansion, but the cell cycle retardation and expansion of the precursor pool were transient. Cell cycle progression in the PTZ-treated group returned to normal after one cell cycle. The numbers of precursors in the SVZ and new neurons in the olfactory bulb, which are descendants of SVZ precursors, were not significantly different from those in control mice more than 2 days after seizures. Because similar effects were observed following electroconvulsive seizures, these responses are likely to be general effects of brief seizures. These results suggest that neurogenesis in the SVZ is more tightly regulated and requires stronger stimuli to be modified than that in the SGZ.

Nuclear lamins are differentially expressed in retinal neurons of the adult rat retina

Lamins are type V intermediate filament proteins that support nuclear membranes. They are divided into A-type lamins, which include lamin A and C, and B-type lamins, which include lamin B1 and B2. In the rat brain, lamin A and C are expressed in relatively equal amounts, while the expressions of lamin B1 and B2 vary depending on the cell type. Lamins play important roles in normal morphogenesis and function. In the nervous system, their abnormal expression causes several neurodegenerative diseases such as peripheral neuropathy, leukodystrophy and lissencephaly. The retina belongs to the central nervous system (CNS) and has widely been used as a source of CNS neurons. We investigated the expression patterns of lamin subtypes in the adult rat retina by immunohistochemistry and found that the staining patterns differed when compared with the brain. All retinal neurons expressed lamin B1 and B2 in relatively equal amounts. In addition, horizontal cells and a subpopulation of retinal ganglion cells expressed lamin A and C, while photoreceptor cells expressed neither lamin A nor C, and all other retinal neurons expressed lamin C only. This differential expression pattern of lamins in retinal neurons suggests that they may be involved in cellular differentiation and expression of cell-specific genes in individual retinal neurons.

The localization and non-genomic function of the membrane-associated estrogen receptor in oligodendrocytes

There is general acceptance that the estrogen receptor can act as a transcription factor. However, estrogens can also bind to receptors that are located at the plasma membrane and stimulate rapid intracellular signaling processes. We recently showed that a membrane-associated estrogen receptor (mER) is present within myelin and at the oligodendrocyte (OL) plasma membrane. To understand the physiological function of mER in OLs, we investigated its cellular localization and involvement in rapid signaling in CG4 cells and OL primary cultures. An ERalpha was expressed along the lacy network of veins in the membrane sheets and in the perikaryon and nucleus in OLs. ERbeta was located in the nucleus, and to a lesser extent along the veins. The expression of ERalpha and ERbeta in OL membranes was confirmed by Western analysis of isolated membranes. OL membranes mainly had truncated forms of ERalpha, 53 and 50 kDa, in addition to some 65 kDa form, whereas ERbeta was a 54 kDa form. CG4 cells and OLs were pulsed with 17alpha- and 17beta-estradiol for various times and the total lysates were analyzed for phosphorylated kinases. Both 17alpha- and 17beta-estradiol elicited rapid phosphorylation of p42/44MAPK, Akt, and GSK-3beta within 8 min. This rapid signaling is consistent with estradiol ligation of a membrane form of ER. Since 17alpha-estradiol is produced at higher concentrations than 17beta-estradiol in the brain of both sexes, signaling via 17alpha-estradiol-liganded mER may have an important function in OLs.

Sulfatide is a negative regulator of oligodendrocyte differentiation: Development in sulfatide-null mice

Galactosylceramide (GalC) and its sulfated analogue, sulfatide, are major galactosphingolipid components of myelin and oligodendrocyte plasma membranes in the nervous system. We previously hypothesized that these galactolipids play functional roles in the regulation of oligodendrocyte terminal differentiation by acting as sensors/transmitters of environmental information. Evidence strongly supports this idea. First, these molecules are initially expressed on the cell surface at the interface at which oligodendrocyte progenitors first enter terminal differentiation. Second, exposure of oligodendrocyte progenitors to anti-GalC/-sulfatide (RmAb) or antisulfatide (O4), but not anti-GalC (O1), antibodies leads to the reversible arrest of oligodendrocyte lineage progression at this interface. Third, in cerebroside galactosyl transferase-null mice (Cgt(-/-)) that are unable to synthesize either GalC or sulfatide, terminal differentiation and morphological maturation of oligodendrocytes are enhanced. In the present study, we examined oligodendrocytes differentiation in cerebroside sulfotransferase-null mice (Cst(-/-)) that lack sulfatide but express GalC. We show that cerebroside sulfotransferase mRNA expression begins already in the embryonic spinal cord and progressively increases with age, that the late progenitor marker POA is not synthesized in the absence of this enzyme, and that, most notably, there is a two- to threefold enhancement in the number of terminally differentiated oligodendrocytes both in culture and in vivo, similar to that in mice lacking both GalC and sulfatide. We conclude that primarily sulfatide, rather than GalC, is a key molecule for the negative regulation of oligodendrocyte terminal differentiation.

Cerebroside sulfotransferase deficiency ameliorates L-selectin-dependent monocyte infiltration in the kidney after ureteral obstruction

Mononuclear cells infiltrating the interstitium are involved in renal tubulointerstitial injury. The unilateral ureteral obstruction (UUO) is an established experimental model of renal interstitial inflammation. In our previous study, we postulated that L-selectin on monocytes is involved in their infiltration into the interstitium by UUO and that a sulfated glycolipid, sulfatide, is the physiological L-selectin ligand in the kidney. Here we tested the above hypothesis using sulfatide- and L-selectin-deficient mice. Sulfatide-deficient mice were generated by gene targeting of the cerebroside sulfotransferase (Cst) gene. Although the L-selectin-IgG chimera protein specifically bound to sulfatide fraction in acidic lipids from wild-type kidney, it did not show such binding in fractions of Cst(-/-) mice kidney, indicating that sulfatide is the major L-selectin-binding glycolipid in the kidney. The distribution of L-selectin ligand in wild-type mice changed after UUO; sulfatide was relocated from the distal tubules to the peritubular capillaries where monocytes infiltrate, suggesting that sulfatide relocated to the endothelium after UUO interacted with L-selectin on monocytes. In contrast, L-selectin ligand was not detected in Cst(-/-) mice irrespective of UUO treatment. Compared with wild-type mice, Cst(-/-) mice showed a considerable reduction in the number of monocytes/macrophages that infiltrated the interstitium after UUO. The number of monocytes/macrophages was also reduced to a similar extent in L-selectin(-/-) mice. Our results suggest that sulfatide is a major L-selectin-binding molecule in the kidney and that the interaction between L-selectin and sulfatide plays a critical role in monocyte infiltration into the kidney interstitium.

Paranodal junction formation and spermatogenesis require sulfoglycolipids

Mammalian sulfoglycolipids comprise two major members, sulfatide (HSO3-3-galactosylceramide) and seminolipid (HSO3-3-monogalactosylalkylacylglycerol). Sulfatide is a major lipid component of the myelin sheath and serves as the epitope for the well known oligodendrocyte-marker antibody O4. Seminolipid is synthesized in spermatocytes and maintained in the subsequent germ cell stages. Both sulfoglycolipids can be synthesized in vitro by using the isolated cerebroside sulfotransferase. To investigate the physiological role of sulfoglycolipids and to determine whether sulfatide and seminolipid are biosynthesized in vivo by a single sulfotransferase, Cst-null mice were generated by gene targeting. Cst(-/-) mice lacked sulfatide in brain and seminolipid in testis, proving that a single gene copy is responsible for their biosynthesis. Cst(-/-) mice were born healthy, but began to display hindlimb weakness by 6 weeks of age and subsequently showed a pronounced tremor and progressive ataxia. Although compact myelin was preserved, Cst(-/-) mice displayed abnormalities in paranodal junctions. On the other hand, Cst(-/-) males were sterile because of a block in spermatogenesis before the first meiotic division, whereas females were able to breed. These data show a critical role for sulfoglycolipids in myelin function and spermatogenesis.

cDNA cloning, genomic cloning, and tissue-specific regulation of mouse cerebroside sulfotransferase

We have isolated a mouse cDNA clone encoding 3'-phosphoadenylylsulfate-galactosylceramide 3'-sulfotransferase (cerebroside sulfotransferase; CST; EC 2.8.2.11) from a kidney cDNA library, using a human CST cDNA clone [Honke, K., Tsuda, M., Hirahara, Y., Ishii, A., Makita, A. & Wada, Y. (1997) J. Biol. Chem. 272, 4864-4868] as a probe. A recombinant protein of the cloned cDNA showed CST activity. The deduced protein is composed of the same 423 amino acids as human CST and its sequence exhibits 84% identity with that of the human counterpart. Northern-blot analysis and subquantitative reverse transcription-PCR (RT-PCR) analysis showed that the CST gene is preferentially transcribed in stomach, small intestine, brain, kidney, lung, and testis, in that order. To examine differences in transcripts in various tissues, we isolated CST cDNA clones from stomach, small intestine, brain, kidney, and testis by 5'-RACE analysis. We found seven different nucleotide sequences in the 5'-UTR, while the DNA sequences of all the isolated cDNA clones were identical in the coding region. In addition, we isolated CST genomic DNA clones from a mouse genomic library. The clones covered all the 5'-UTR sequences and coding exons including 3'-UTR. RT-PCR analyses of CST mRNAs from various tissues confirmed that CST transcripts are tissue-specifically spliced by alternative use of multiple exons 1. These observations suggest that the tissue-specific expression of the CST gene is explained by alternative usage of multiple 5'-UTR exons flanked with tissue-specific promoters.

[Simultaneous analysis and detection of pesticides in fresh fruits and vegetables by HPLC and GC]

A method was established for simultaneous determination of pesticide residue in fresh fruits and vegetables by HPLC and GC. CH3CN extraction/NaCl partiton method was used in order to recover hydrophilic pesticide such as acephate, methamidophos. Dimethoate and methamidophos from okra and DDVP from strawberry were detected by GC. On the other hand confirmation method by GC and GC/MS was studied for peaks detected by HPLC with UV and/or FL detector. OPP, TBZ, imazalil chlorpyrifos etc. in citrus fruits were detected by the proposed method.

Purification and characterization of chondroitin 4-sulfotransferase from the culture medium of a rat chondrosarcoma cell line

Chondroitin 4-sulfotransferase, which transfers sulfate from 3'-phosphoadenosine 5'-phosphosulfate to position 4 of N-acetylgalactosamine in chondroitin, was purified 1900-fold to apparent homogeneity with 6.1% yield from the serum-free culture medium of rat chondrosarcoma cells by affinity chromatography on heparin-Sepharose CL-6B, Matrex gel red A-agarose, 3',5'-ADP-agarose, and the second heparin-Sepharose CL-6B. SDS-polyacrylamide gel electrophoresis of the purified enzyme showed two protein bands. Molecular masses of these protein were 60 and 64 kDa under reducing conditions and 50 and 54 kDa under nonreducing conditions. Both the protein bands coeluted with chondroitin 4-sulfotransferase activity from Toyopearl HW-55 around the position of 50 kDa, indicating that the active form of chondroitin 4-sulfotransferase is a monomer. Dithiothreitol activated the purified chondroitin 4-sulfotransferase. The purified enzyme transferred sulfate to chondroitin and desulfated dermatan sulfate. Chondroitin sulfate A and chondroitin sulfate C were poor acceptors. Chondroitin sulfate E from squid cartilage, dermatan sulfate, heparan sulfate, and completely desulfated N-resulfated heparin hardly served as acceptors of the sulfotransferase. The transfer of sulfate to the desulfated dermatan sulfate occurred preferentially at position 4 of the N-acetylgalactosamine residues flanked with glucuronic acid residues on both reducing and nonreducing sides.

Cancer-associated expression of glycolipid sulfotransferase gene in human renal cell carcinoma cells

Human renal cell carcinoma (RCC) tissue and a cell line derived therefrom, SMKT-R3, showed markedly increased glycolipid sulfotransferase [cerebroside sulfotransferase (CST); EC 2.8.2.11] activity and accumulated sulfoglycolipids. Recently, we cloned a human CST cDNA from a SMKT-R3 cDNA library (K. Honke et al., J. Biol. Chem., 272: 4864-4868, 1997). In this study, we investigated the expression of the CST gene in seven human RCC lines (SMKT-R1, SMKT-R2, SMKT-R3, SMKT-R4, TOS-1, TOS-2, and ACHN) and their normal counterpart, human renal proximal tubular cells. On Northern blot analysis, a marked increase of CST mRNA was observed in every RCC line, except for ACHN, as compared with normal cells. ACHN cells showed a slightly increased level of CST mRNA. CST activity was correlated with the amount of mRNA. Sulfoglycolipid analysis revealed that expression of lactosylceramide sulfate was correlated with the CST level. Furthermore, we examined the effects of epidermal growth factor (EGF), tetradecanoylphorbol-13-acetate, and genistein, which are known to regulate CST activity in SMKT-R3 cells, on CST-gene expression in various RCC cells. On treatment with EGF, CST mRNA time-dependently increased in accord with its activity in SMKT-R3 cells. Yet, augmentation by EGF was only observed in SMKT-R3. In contrast, a reduction of CST mRNA and activity by tetradecanoylphorbol-13-acetate and genistein was observed in all of the lines examined. Taken together, these findings indicate that in human RCC cells, the CST gene is generally overexpressed via a signaling pathway involving protein kinase-C and tyrosine kinases.

Changes in phenytoin concentrations in blood and cerebrospinal fluid caused by direct hemoperfusion in a patient intoxicated with phenytoin

We performed direct hemoperfusion (DHP) 5 times on a patient with consciousness disorder and phenytoin intoxication. We then measured the phenytoin concentrations in her cerebrospinal fluid (CSF) and blood at various times. After the first DHP session, consciousness began to improve, and it normalized after the fourth DHP session when the blood concentration of phenytoin had decreased from 54.0 microg/ml to 16.5 microg/ml. The average plasma phenytoin elimination rate of DHP was 18.0% over 120-180 min. The concentration of phenytoin in the CSF decreased as that in the blood was lowered by DHP. The average reduction rate of phenytoin in the CSF after a DHP session was 23.7%, which was similar to the rate of elimination from the blood. The CSF/blood phenytoin ratio was 0.17, and no marked changes were detected before or after a DHP session.

Molecular cloning and expression of cDNA encoding human 3'-phosphoadenylylsulfate:galactosylceramide 3'-sulfotransferase

We have isolated a cDNA clone encoding human 3'-phosphoadenylylsulfate:galactosylceramide 3'-sulfotransferase (EC 2.8.2.11). Degenerate oligonucleotides, based on amino acid sequence data for the purified enzyme, were used as primers to amplify fragments of the gene from human renal cancer cell cDNA by the polymerase chain reaction method. The amplified cDNA fragment was then used as probe to screen a human renal cancer cell cDNA library. The isolated cDNA clone contained an open reading frame encoding 423 amino acids including all of the peptides that were sequenced. The deduced amino acid sequence predicts a type II transmembrane topology and contains two potential N-glycosylation sites. There is no significant homology between this sequence and either the sulfotransferases cloned to date or other known proteins. Northern blot analysis demonstrated that a 1.9-kilobase mRNA was unique to renal cancer cells. When the cDNA was inserted into the expression vector pSVK3 and transfected into COS-1 cells, galactosylceramide sulfotransferase activity in the transfected cells increased from 8- to 16-fold over that of controls, and the enzyme product, sulfatide, was expressed on the transformed cells.

Pure Rotational Spectra of SO: Rare Isotopomers in the 80-GHz to 1.1-THz Region

Pure rotational spectra of rare isotopomers of sulfur monoxide, SO, have been recorded with the Cologne Terahertz Spectrometer, Germany, and the millimeter- and submillimeter-wave spectrometer at Nobeyama, Japan. In total, 176 new transitions have been measured in the X3Sigma- electronic ground state, including the first laboratory detection of the rare isotopomer 36SO. New lines are also reported for 33SO and S17O in their vibrational ground states, and for 33SO and S18O in the first excited vibrational state. A simultaneous fit of 451 transitions has led to an improved set of isotopically invariant parameters for rotation and fine structure. Hyperfine structure constants for 33SO and S17O have been obtained also from the global fit, including first values for the magnetic nuclear spin-rotation interaction. These are compared to other molecules. The isotopically invariant parameters allow precise frequency predictions for the submillimeter-wave region far beyond 1 THz for all SO isotopomers, of importance to astrophysical applica- tions.

Enzymatic sulfation of galactose residue of keratan sulfate by chondroitin 6-sulfotransferase

We have previously found that the purified chondroitin 6-sulfotransferase (C6ST), which transfers sulfate from 3'-phosphoadenosine 5'-phosphosulfate (PAPS) to position 6 of N-acetylgalactosamine in chondroitin, catalyzed the sulfation of keratan sulfate, and that both the C6ST activity and the keratan sulfate sulfotransferase (KSST) activity were expressed in COS-7 cells when C6ST cDNA was transfected. In this report we describe some properties of the KSST activity contained in the purified C6ST, and characterize the sulfated products formed from keratan sulfate and partially desulfated keratan sulfate. Optimal pH, requirement for cationic activators, and Km value for PAPS of the KSST activity were very similar to those of the C6ST activity. 35S-Labeled glycosaminoglycans formed from keratan sulfate and partially desulfated keratan sulfate were N-deacetylated by treatment with hydrazine/hydrazine sulfate and then cleaved with HNO2 at pH 4, and the resulting products were reduced with NaB3H4. Analysis of the degradation products with paper chromatography and high performance liquid chromatography provided evidence that C6ST transferred sulfate to position 6 of galactose residue which was glycosidically linked to N-acetylglucosamine 6-sulfate residue or to N-acetylglucosamine residue. Northern blot analysis using poly (A)+ RNA from 12-d-old chick embryos indicated that the message of C6ST was expressed not only in the cartilage but also in the cornea in which keratan sulfate is actively synthesized.

[Current status and problems of home care for patients with terminal cancer from the viewpoint of local clinics]

On the basis of investigations of 15 patients from our clinic with terminal cancer who were treated by home hospice care, and questionnaires filled out by their caretakers, we examined the current status and problems of the home hospice care system with respect to four phases, namely, the period of preparation for home care (hospitalization period), stable period, terminal period, and the period immediately before death. [Preparation period] The following problems occurred in this phase: introduction of pain management and nutrition management was insufficient; there were only a few cases in which the patient chose home care of his or her own will; and sufficient instructions were not given to caretakers on discharge from the hospital, with respect to medical treatment at home. [Stable period] In two of the four cases in which patients complained of severe pain, the pain was not alleviated because pain management was provided only at the outpatient clinics of the hospital, and collaboration between hospitals and our clinic was insufficient. [Terminal period] Two patients could not be admitted to the hospital upon sudden exacerbation of the condition, suggesting the need to establish a system in which large hospitals can cope with sudden exacerbation of their condition of patients with terminal cancer treated at home. [Period immediately before death] Of the 14 patients who died, 7 died at home and 7 died in the hospital or during transport to the hospital. Three subjects died within a few days after admission. Two of the subjects who died in the hospital or during transport had hoped to stay home until the last moment. Further improvement of the system is necessary in order to meet the needs of terminal cancer patients who wish to die at home. On the basis of the cases taken care of at our clinic, we examined the home care system according classification into three types; hospital-outpatient clinic type; hospital-home care type; and clinic-home care type. An ideal system for the treatment of patients with terminal cancer who hope to stay at home until the last possible moment seems to be the clinic-home care type in which a primary care team that is able to dispatch physicians and nurses, and an around-the-clock support system, are supported by outside organizations and specialists.

[Studies on the identification of sulfadimidine in pork by high performance liquid chromatography with photodiode array detector and gas chromatograph-mass spectrometry]

Sulfadimidine (SDD) was detected in pork imported from Mexico by HPLC with gradient elution system. UV spectrum of the peak was measured and confirmed by photodiode array detector, moreover identified by GC/MS after methylation with diazomethane. Content of SDD in the sample was 0.1 ppm and detection limit of SDD by the proposed method was 0.02 ppm. Application of this method to CLP, SMR, SMM, SDM and SQX was studied, and satisfactory results were obtained.