IMPORTANCE Although mutations in 26 causative genes have been identified in the spinocerebellar ataxias (SCAs), the causative genes in a substantial number of families with SCA remain unidentified.OBJECTIVE To identify the causative gene of SCA in 2 Japanese families with distinct neurological symptoms and radiological presentations. DESIGN, SETTING, AND PARTICIPANTSClinical genetic study at a referral center of 11 members from 2 Japanese families, which started in 1997. MAIN OUTCOMES AND MEASURESResults of neurological examinations and radiological evaluations. The causative mutation was identified using genome-wide linkage analysis and next-generation sequencing.RESULTS Affected members (9 of 11 members [81.8%]) showed slowly progressive cerebellar ataxia (all 9 members [100%]), ocular movement disturbance (all 9 members [100%]), and pyramidal tract signs (8 of 9 members [88.9%]) with an age at onset between the second and sixth decades of life. Besides cerebellar and pontine atrophy, magnetic resonance imaging of the brain revealed the hot cross bun sign (4 of 6 members [66.7%]), pontine midline linear hyperintensity (2 of 6 members [33.3%]), or high intensity in the middle cerebellar peduncle (1 of 6 members [16.7%]), which are all reminiscent of multiple system atrophy in tested patients. Using linkage analysis combined with exome and whole-genome sequencing, we identified a novel heterozygous mutation in the ELOVL fatty acid elongase 4 (ELOVL4) gene (c.736T>G, p.W246G) in both families. Haplotype analysis indicated that it was unlikely that these 2 Japanese families shared a common ancestor. Although a missense mutation in ELOVL4 (c.504G>C, p.L168F) was recently reported to be associated with SCA with erythrokeratodermia variabilis (SCA34) in a French-Canadian family, signs of erythrokeratodermia variabilis were absent in our families. CONCLUSIONS AND RELEVANCECombined with the results of the family with SCA34 reported previously, this report confirms that mutations in ELOVL4 can cause dominantly inherited neurodegeneration severely affecting the cerebellum and brainstem. We should be aware that the presence of multiple system atrophy-like features on magnetic resonance imaging scans, together with cerebellar and brainstem atrophy, suggests SCA34, even when erythrokeratodermia variabilis is absent. The present study further broadened the spectrum of the clinical presentations of SCA34 associated with mutations in ELOVL4, which is involved in the biosynthesis of very long-chain fatty acids.

Apoptosis is a key for CD4+ T cell destruction in HIV-1–infected patients. In this study, human peripheral blood lymphocyte (PBL)-transplanted nonobese diabetic (NOD)-severe combined immunodeficient (SCID) (hu-PBL-NOD-SCID) mice were used to examine in vivo apoptosis after HIV-1 infection. As the hu-PBL-NOD-SCID mouse model allowed us to see extensive infection with HIV-1 and to analyze apoptosis in human cells in combination with immunohistological methods, we were able to quantify the number of apoptotic cells with HIV-1 infection. As demonstrated by terminal deoxynucleotidyl transferase–mediated dUTP nick-end labeling (TUNEL), massive apoptosis was predominantly observed in virus-uninfected CD4+ T cells in the spleens of HIV-1–infected mice. A combination of TUNEL and immunostaining for death-inducing tumor necrosis factor (TNF) family molecules indicated that the apoptotic cells were frequently found in conjugation with TNF-related apoptosis-inducing ligand (TRAIL)-expressing CD3+CD4+ human T cells. Administration of a neutralizing anti-TRAIL mAb in HIV-1–infected mice markedly inhibited the development of CD4+ T cell apoptosis. These results suggest that a large number of HIV-1–uninfected CD4+ T cells undergo TRAIL-mediated apoptosis in HIV-infected lymphoid organs.

No abstract

We have discovered that an N-terminal deletion mutant of a membrane protein, CD63, (CD63DN) blocks entry of CXCR4-using, T-cell tropic human immunodeficiency virus type 1 (X4 HIV-1) by suppressing CXCR4 surface expression. This suppression was observed for CXCR4 but not for CD4, CCR5, CD25, CD71 or other tetraspanin proteins. The suppression of CXCR4 expression on the plasma membrane appeared to be caused by mislocalization of CXCR4 and exclusive transportation of CXCR4 toward intracellular organelles, mainly late endosomes/ lysosomes. Our data suggest that CXCR4 trafficking can be modified in terms of its recruitment to the plasma membrane without enhancing the degradation or arresting vesicular transport of CXCR4.

Human immunodeficiency virus type 1 (HIV-1)-infected macrophages damage mature neurons in the brain, although their effect on neuronal development has not been clarified. In this study, we show that HIV-1-infected macrophages produce factors that impair the development of neuronal precursor cells and that soluble viral protein R (Vpr) is one of the factors that has the ability to suppress axonal growth. Cell biological analysis revealed that extracellularly administered recombinant Vpr (rVpr) clearly accumulated in mitochondria where a Vpr-binding protein adenine nucleotide translocator localizes and also decreased the mitochondrial membrane potential, which led to ATP synthesis. The depletion of ATP synthesis reduced the transportation of mitochondria within neurites. This mitochondrial dysfunction inhibited axonal growth even when the frequency of apoptosis was not significant. We also found that point mutations of arginine (R) residues to alanine (A) residues at positions 73, 77, and 80 rendered rVpr incapable of causing mitochondrial membrane depolarization and axonal growth inhibition. Moreover, the Vpr-induced inhibition was suppressed after treatment with a ubiquinone analogue (ubiquinone-10). Our results suggest that soluble Vpr is a major viral factor that causes a disturbance in neuronal development through the induction of mitochondrial dysfunction. Since ubiquinone-10 protects the neuronal plasticity in vitro, it may be a therapeutic agent that can offer defense against HIV-1-associated neurological disease.

Dark anaerobic fermentation in the green algae Chiamydomonas MGA 161, Chlamydomonas reinhardtii, Chlorella pyrenoidosa, and Chlorococcum minutum was studied. Our isolate, Chiamydomonas MGA 161, was unusual in having high H2 but almost no formate. The fermentation pattern in Chlamydomonas MGA 161 was altered by changes in the NaCI or NHI-CI concentration. Glycerol formation increased at low (0.1%) and high (7%) NaCI concentrations; starch degradation, and formation of ethanol, H2, and CO2 increased with the addition of NH4CI to above 5 millimolar in N-deficient cells. C. reinhardtii and C. pyrenoidosa exhibited a very similar anaerobic metabolism, forming formate, acetate and ethanol in a ratio of about 2:2:1. C. minutum was also unusual in forming acetate, glycerol, and CO2 as its main products, with H2, formate, and ethanol being formed in negligible amounts. In the presence of CO, ethanol formation increased twofold in Chiamydomonas MGA 161 and C. reinhardtii, but the fermentation pattern in C. minutum did not change. An experiment with hypophosphite addition showed that dark H2 evolution of the Escherichia coli type could be ruled out in Chiamydomonas MGA 161 and C. reinhardtii. Among the green algae investigated, three fermentation types were identified by the distribution pattern of the end products, which reflected the consumption mode of reducing equivalents in the cells.Green algae produce hydrogen under dark anaerobic conditions, as first observed by Gaffron and Rubin (8). The whole process of dark H2 evolution is mediated through the fermentative degradation of accumulated starch. Use of this property in a stable biophotolysis system makes possible temporal separation of H2 production from photosynthetic 02 production. Lightdependent H2 production without an O2 defense system soon comes to a stop because of inhibition by the O2 produced (10, 28). Studies with a freshwater alga, Chlamydomonas reinhardtii, showed an intermittent but stable 02/H2 production system in an alternating light/dark cycle (24,25). A halotolerant green alga, Chlamydomonas MGA 161, has been isolated, and both growth and dark H2 evolution in this alga are active (26 ucts of green algae (9,17,19). Klein and Betz (16) reported on the fermentation metabolism with no formate formation in Chlamydomonas moewusii. Gfeller and Gibbs (9) and Kreuzberg (19) reported that formate, acetate, and ethanol are produced in a ratio of 2:1:1 in the dark incubation of C. reinhardtii. The fermentation process is regulated by ATP and reducing equivalents generated during starch degradation. The ATP concentration within Chlorella cells increases slightly with active hydrogenase under dark anaerobic conditions, accompanied by an increase in NADH and a decrease in NADPH (22). Reducing equivalents are consumed by the formation of fermentation products for a constant metabolic flux; the reducing power is used for the formation of H2 (from H+), formate (from C02), glycerol (from acetonephosphate) or ethanol (from acetyl-CoA) (17).In this paper, we rep...

HIV-1 infection in the brain induces neuronal apoptosis leading to HIV-associated dementia. To explore the underlying mechanism, we developed a murine model by using human peripheral blood mononuclear cell (

No abstract