Motohiro Yukitake

The 14-3-3 Protein Detectable in the Cerebrospinal Fluid of Patients with Prion-Unrelated Neurological Diseases Is Expressed Constitutively in Neurons and Glial Cells in Culture

The 14-3-3 protein belongs to a family of 30-kD proteins originally identified by two-dimensional analysis of brain protein extracts. Recently, the detection of the 14-3-3 protein in the cerebrospinal fluid (CSF) is utilized as a highly reliable test for the premortem diagnosis of prion diseases such as Creutzfeldt-Jakob disease. For the initial step, to clarify the biological implication of the CSF 14-3-3 protein in these diseases, its expression was investigated in neural tissues and cultures and CSF samples from patients with a variety of neurological diseases by Western blot analysis and immunocytochemistry. The constitutive expression of the 14-3-3 protein was identified in all neural and nonneural tissues examined. It was expressed in all neurons, astrocytes, oligodendrocytes, and microglia in culture with its location in both cytoplasmic and nuclear regions. The 14-3-3 protein was detected in the CSF of 8 out of 71 patients, including 1 Gerstmann-Sträussler-Scheinker disease patient and 7 patients with prion-unrelated neurological diseases, such as meningoencephalitis of viral, bacterial, or tuberculous origin, multiple sclerosis, and mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes. These results suggest that the 14-3-3 protein expressed constitutively at substantial levels in both neurons and glial cells might be released into the CSF as a disease-nonspecific consequence of the extensive brain damage and indicate that the analysis of the 14-3-3 protein in the CSF is not useful as a screening test for prion diseases.

Interleukin-15, a T-cell growth factor, is expressed in human neural cell lines and tissues

Interleukin-15 (IL-15) is a novel cytokine which shares activities and receptor components with IL-2. To investigate the biological roles of IL-15 in the human nervous system, we examined the expression of mRNAs for IL-15 and the IL-15 receptor three subunits (IL-15alpha, IL-2Rbeta and IL-2Rgamma) in human neural cell lines and tissues using reverse transcription-polymerase chain reaction and Southern blot analysis. The constitutive expression of high levels of IL-15 mRNA was observed in all the cell lines examined, including Y79 retinoblastoma, IMR-32 neuroblastoma, SK-N-SH neuroblastoma, U-373MG glioma, KG-1-C glioma, NTera2 teratocarcinoma and neurons derived from NTera2 cells following treatment with retinoic acid (RA). Among these cell lines, IL-15 protein was detectable at high levels in culture supernatants of SK-N-SH cells and NTera2-derived neurons. The expression of an alternatively-spliced transcript of the IL-15 gene was up-regulated in NTera2 cells during RA-induced neuronal differentiation, suggesting the existence of differentiation-dependent transcriptional regulation. The expression of IL-15 mRNA was also identified in the human cerebral and cerebellar tissues, peripheral nerve and skeletal muscle, while the mRNAs for the complete set of IL-15R components were detectable only in U-373MG cells, cerebral and cerebellar tissues at significant levels. These results indicate that the expression of IL-15 but not of IL-15R mRNA is universal in human neural cell lines and tissues and raise the possibility that IL-15 acts as a neuroimmune regulatory factor in the human central nervous system.

Adult-onset Krabbe disease with homozygous T1853C mutation in the galactocerebrosidase gene

A 51-year-old woman developed a slowly progressive spastic paraparesis and diminished vibration sense beginning at age 38. Intellectual capacity was normal. Krabbe disease was confirmed by markedly reduced leukocyte galactocerebrosidase (GALC) activity, typical inclusions in Schwann cell cytoplasm, and an identification of the homozygous point mutation T1835C(Leu618Ser) in the GALC gene. T2-weighted MRI of the brain showed symmetric high-signal-intensity lesions in the bilateral frontoparietal white matter, the centrum semiovale, and the posterior limb of the internal capsule with sparing of the periventricular white matter. This case is unusual because of the late onset, protracted clinical course, and MRI findings of demyelination confined to the corticospinal tracts.

Constitutive and cytokine-inducible expression of prion protein gene in human neural cell lines.

Prion diseases are a group of neurodegenerative disorders characterized by intracerebral accumulation of a pro-tease-resistant prion protein (PrPSc) that causes extensive neuronal degeneration and astrogliosis. The regulation of prion protein (PrP) gene expression by a panel of glial and neuronal cytokines (TNF-α, IFN–γ, IL-1β, IL-10, and TGF-β1) was investigated in human neural cell lines by reverse transcription-polymerase chain reaction and Northern blot analysis. The constitutive expression of PrP mRNA was identified in all human neural cell lines and tissues examined including Y79 retinoblastoma, IMR-32 neuroblastoma, SK-N-SH neuroblastoma, U-373MG astrocytoma, KG-l-C glioma, NTera2 teratocarcinoma, NTera2-derived differentiated neurons (NTera2-N), peripheral nerve, and cerebral and cerebellar tissues. In SK-N-SH cells, a 48 hour (h) treatment with 100 ng/ml IL-lβ, 100 ng/ml TNF-α, or 100 nM phorbol 12-myristate 13-acetate induced a 2.7− to 4.2-fold increase in the level of PrP mRNA, while the exposure to 100 ng/ml IFN–γ resulted in a 50% decrease. By contrast, none of these cytokines significantly altered the levels of PrP mRNA in IMR-32, NTera2-N, or U-373MG cells. These results indicate that the PrP gene expression is constitutive in a wide range of human neural cell lines and tissues where it is controlled by cell type-specific regulatory mechanisms.

Detection of the 14-3-3 protein in the cerebrospinal fluid of Japanese multiple sclerosis patients presenting with severe myelitis

Recent studies showed that the 14-3-3 protein is detectable in the cerebrospinal fluid (CSF) of prion-unrelated neurological diseases, such as meningoencephalitis and myelitis. To investigate the possible association between the amounts of the 14-3-3 protein in the CSF and the clinical severity of multiple sclerosis (MS), its levels were determined by Western blot in the CSF of the patients with relapsing-remitting MS (RRMS) (n=10), secondary progressive MS (SPMS) (n=7), primary progressive MS (PPMS) (n=2), and non-MS inflammatory diseases of the CNS (n=5). The 14-3-3 protein was identified in seven CSF samples, including four patients with SPMS in acute relapse, one with SPMS in remission accompanied by fresh cerebral infarction, one with RRMS in acute relapse, and one with human T-lymphotropic virus type I (HTLV-I)-associated myelopathy. The patients positive for the CSF 14-3-3 protein immunoreactivity showed more severe disability and higher levels of pleocytosis, protein, IgG, beta2-microglobulin, and neuron-specific enolase in the CSF, compared with those negative for its immunoreactivity. Four of these patients exhibited extensive lesions distributed along multiple vertebral segments in the spinal cord on MRI. In contrast, none of the MS patients without an extensive involvement of the spinal cord showed the CSF 14-3-3 protein immunoreactivity. These results suggest that detection of the 14-3-3 protein in the CSF provides a marker for severe inflammation-induced extensive damage of the central nervous system tissues responsible for poor therapeutic responses and irreversible neurological deficits in MS.

Assessment of MRI criteria for MS in Japanese MS and HAM/TSP

Article abstract-We evaluated the usefulness of the MRI criteria for multiple sclerosis (MS) proposed by Paty et al and Fazekas et al in 36 Japanese MS patients, using HTLV-I-associated myelopathy (HAM)/tropical spastic paraparesis (TSP) as the control. Although 30 of 36 HAM/TSP patients had multiple white matter lesions on T2-weighted cranial MRI, only two fulfilled the MRI criteria for MS. At the same time, 31 of the 36 MS patients fulfilled the primary MRI criterion, yielding 93% specificity and 86% sensitivity for the criterion. MS has disease-specific MRI abnormalities. NEUROLOGY 1995;45: 30-33

Interferon β-responsive inclusion body myositis in a hepatitis C virus carrier

Although an immune-mediated theory has been proposed for the pathogenesis of inclusion body myositis (IBM),1,2⇓ immunosuppressive treatment is not beneficial. We report a case of IBM occurring in a hepatitis C virus (HCV) carrier and showing improvement with the administration of a high dose of interferon-β (IFNβ). A 68-year-old man was admitted because of generalized muscle weakness that progressed for over 8 years. Eight years earlier, he had developed chronic renal failure due to hyperuricemia and was treated with hemodialysis three times a week. At the induction of hemodialysis he was found to be a HCV carrier. Family history was unremarkable. General physical examination revealed no abnormalities other than hepatomegaly. On neurologic examination, symmetric weakness and atrophy of muscles were noted in all extremities. He was unable to stand, remain standing, or walk. Evaluation using manual muscle testing (MMT) scores included scores of 5 (normal) to 0 (complete paralysis). The results were …

Development of HTLV-I-associated myelopathy after blood transfusion in a patient with aplastic anemia and a recipient of a renal transplant

We report the development of rapid progressive HTLV-I-associated myelopathy (HAM) after blood transfusion in two immunosuppressed patients, one of whom had aplastic anemia and the other was the recipient of a renal transplant receiving immunosuppressive chemotherapy. Spastic paraparesis developed 11 or 16 months after transfusion and rapidly progressed to a wheelchair-bound state. The present 2 cases suggest that the coexistent immunosuppression may play an important role in the rapid development of HAM in transfusion-acquired cases.

Constitutive and heat-inducible expression of HSP105 in neurons and glial cells in culture

THE constitutive and heat-inducible expression of HSP105 was investigated in newborn mouse brain cell cultures by Northern blotting, Western blotting and immunocytochemistry. HSP105 was expressed most abundantly in the brain among the various tissues examined. HSP105 mRNA and protein were both present at substantial levels in brain cell cultures under unstressed conditions and up-regulated greatly during 3–4 8h following exposure to heat stress (4 3°C/2 0min). HSP105 was expressed in nearly all neurons, oligodendrocytes, microglia and astrocytes with its location of both cytoplasmic and nuclear regions under unstressed and heatstressed conditions. HSP105 expression was significantly down-regulated in astrocytes following treatment with IL-β or TNF-α (5 0ng/ml for 6 days), both of which are known growth-stimulatory cytokines for astrocytes. These results indicate that HSP105 is constitutive and heat-inducible HSP in neurons and glial cells in which its expression is under the control of both stressful stimuli and growth-regulatory factors.

Cultured skin fibroblasts isolated from mice devoid of the prion protein gene express major heat shock proteins in response to heat stress

Recent evidence has suggested that molecular chaperones participate in the conformational change between the normal cellular prion protein (PrPC) and its scrapie isoform (PrPSc). To study a role of PrPC in the regulation of expression of heat shock proteins (HSPs), a group of molecular chaperones, heat-induced expression of major HSPs (HSP105, HSP90alpha, HSP72, HSC70, HSP60, and HSP25) was investigated in cultured skin fibroblasts isolated from the mice homogeneous for a disrupted PrP gene (PrP-/- mice) by Western blot analysis and immunocytochemistry. Two lines of fibroblasts were established and designated SFK derived from the PrP-/- mice and SFH derived from the PrP+/+ mice, respectively. In both SFK and SFH cells, HSP105, HSP72, and HSP25 were expressed at low levels under unstressed conditions but they were induced markedly following exposure to heat stress (43 degreesC/20 min) at 3-72 h postrecovery. In both cell types, HSC70 and HSP60 were expressed at high levels under unstressed conditions and their levels remained unchanged after heat shock treatment. HSP90alpha was undetectable in both cell types under any conditions examined. The pattern of expression, induction, and subcellular location of HSP105, HSP72, HSC70, HSP60, and HSP25 was not significantly different between SFK and SFH cells under unstressed and heat-stressed conditions. Furthermore, the levels of constitutive expression of HSP105, HSC70, HSP60, and HSP25 were similar between the brain tissues isolated from the PrP-/- and PrP+/+ mice. These results indicate that HSP induction is not affected by either the existence or the absence of PrPC in the cells.