Keiko Akiyama

Adenoviral expression of TDP‐43 and FUS genes and shRNAs for protein degradation pathways in rodent motoneurons in vitro and in vivo

Formation of cytoplasmic aggregates in neuronal and glial cells is one of the pathological hallmarks of amyotrophic lateral sclerosis (ALS). Mutations in two genes encoding transactivation response (TAR) DNA‐binding protein 43 (TDP‐43) and fused in sarcoma (FUS), both of which are main constituents of cytoplasmic aggregates, have been identified in patients with familial and sporadic ALS. Impairment of protein degradation machineries has also been recognized to participate in motoneuron degeneration in ALS. In the present study, we produced recombinant adenovirus vectors encoding wild type and mutant TDP‐43 and FUS, and those encoding short hairpin RNAs (shRNAs) for proteasome (PSMC1), autophagy (ATG5), and endosome (VPS24) systems to investigate whether the coupled gene transductions in motoneurons by these adenoviruses elicit ALS pathology. Cultured neurons, astrocytes and oligodendrocytes differentiated from adult rat neural stem cells and motoneurons derived from mouse embryonic stem cells were successfully infected with these adenoviruses showing cytoplasmic aggregate formation. When these adenoviruses were injected into the facial nerves of adult rats, exogenous TDP‐43 and FUS proteins were strongly expressed in facial motoneurons by a retrograde axonal transport of the adenoviruses. Co‐infections of adenovirus encoding shRNA for PSMC1, ATG5 or VPS24 with TDP‐43 or FUS adenovirus enhanced cytoplasmic aggregate formation in facial motoneurons, suggesting that impairment of protein degradation pathways accelerates formation of TDP‐43 and FUS‐positive aggregates in ALS.

The severe clinical phenotype for a heterozygous Fabry female patient correlates to the methylation of non-mutated allele associated with chromosome 10q26 deletion syndrome

Heterozygous Fabry females usually have an attenuated form of Fabry disease, causing them to be symptomatic; however, in rare cases, they can present with a severe phenotype. In this study, we report on a 37-year-old woman with acroparesthesia, a dysmorphic face, left ventricular hypertrophy, and intellectual disability. Her father had Fabry disease and died due to chronic renal and congestive cardiac failure. Her paternal uncle had chronic renal failure and intellectual disability, and her paternal aunt was affected with congestive cardiac failure. The patient has two sisters with no significant medical illness. However, her nephew has acroparesthesia, anhidrosis, and school phobia, and her niece shows mild phenotypes. The patients enzyme analysis showed very low α-galactosidase A (α-gal A) activity in dried blood spot (DBS), lymphocytes, and skin fibroblasts with massive excretion of Gb3 and Gb2 in urine and lyso-Gb3 in DBS and plasma. Electron microscopic examination showed a large accumulation of sphingolipids in vascular endothelial cells and keratinocytes. Chromosomal analysis and comparative genomic hybridization microarray showed 10q26 terminal deletion. Molecular data showed a novel heterozygous stop codon mutation in exon 1 of the GLA gene in her sisters and niece, and a hemizygous state in her nephew. When we checked the methylation status, we found her non-mutated allele in the GLA gene was methylated. However, the non-mutated alleles of her sisters were non-methylated, and those of her niece were partially methylated. The chromosomal and methylation study may speculate the severity of her clinical phenotypes.

Application of a diagnostic methodology by quantification of 26:0 lysophosphatidylcholine in dried blood spots for Japanese newborn screening of X-linked adrenoleukodystrophy

X-linked adrenoleukodystrophy (X-ALD) is a rare inherited metabolic disease that results in the accumulation of very long chain fatty acids (VLCFA) in plasma and all tissues. Recent studies regarding cerebral X-ALD (CALD) treatment emphasize the importance of its early diagnosis. 26:0 lysophosphatidylcholine (LysoPC) is a sensitive biomarker for newborn screening of X-ALD, while its application for Japanese DBS is unclear. Therefore, we evaluated the feasibility of 20:0 LysoPC and 24:0 LysoPC along with 26:0 LysoPC for diagnosing X-ALD in a cohort of newborns (n = 604), healthy adults (n = 50) and patients (n = 4). Results indicated that 26:0 LysoPC had strong significance for discrimination of patients by the amounts of 2.0 to 4.0 and 0.1 to 1.9 pmol/punch for patients and newborns/healthy adults, respectively. Based on these values, we recommend that further diagnostic confirmation is essential if the amount of 26:0 LysoPC in DBS is above 1.7 pmol/punch.

Ten-year-long enzyme replacement therapy shows a poor effect in alleviating giant leg ulcers in a male with Fabry disease

Fabry disease is an X-linked lysosomal storage disorder caused by a deficiency of α-galactosidase A (α-gal A), leading to the progressive accumulation of glycosphingolipids. Classical hemizygous males usually present symptoms, including pain and paresthesia in the extremities, angiokeratoma, hypo- or anhidrosis, abdominal pain, cornea verticillata, early stroke, tinnitus, and/or hearing loss, during early childhood or adolescence. Moreover, proteinuria, renal impairment, and cardiac hypertrophy can appear with age. Enzyme replacement is the most common therapy for Fabry disease at present which has been approved in Japan since 2004. We report a case involving a 27-year-old male with extreme terminal pain, anhidrosis, abdominal pain, tinnitus, hearing impairment, cornea verticillata, and recurrent huge ulcers in the lower extremities. At the age of 16 years, he was diagnosed with Fabry disease with a positive family history and very low α-gal A activity. He then received enzyme replacement therapy (ERT) with recombinant human agalsidase beta at 1 mg/kg every 2 weeks for 10 years. Throughout the course of ERT, his leg ulcers recurred, and massive excretion of urinary globotriaosylceramide and plasma globotriaosylsphingosine was observed. Electron microscopy of the venous tissue in the regions of the ulcer showed massive typical zebra bodies in the vascular wall smooth muscle cells.

Characteristics of PPT1 and TPP1 enzymes in neuronal ceroid lipofuscinosis (NCL) 1 and 2 by dried blood spots (DBS) and leukocytes and their application to newborn screening

We first characterized PPT1 and TPP1 enzymes in dried blood spots (DBS), plasma/serum, and leukocytes/lymphocytes using neuronal ceroid lipofuscinosis (NCL) 1 and 2 patients and control subjects. PPT1 enzyme had only one acid form in control DBS, plasma/serum, and leukocytes/lymphocytes and showed deficient activities in these samples from NCL 1 patients. Conversely, TPP1 enzymes in control DBS and leukocytes/lymphocytes consisted of two forms, an acidic form and a neutral form, whereas serum TPP1 enzyme had only a neutral form. In control subjects, the optimal pH of PPT1 enzyme in DBS, plasma/serum, and leukocytes/lymphocytes was 4.5 to 5.0 in the acidic form, whereas TPP1 enzyme in control DBS and leukocytes/lymphocytes was pH 4.5 and 6.5, respectively. In NCL 1 and 2, both PPT1 and TPP1 enzyme activities in DBS, plasma, and leukocytes/lymphocytes were markedly reduced in acidic pH, whereas heterozygotes of NCL 1 and 2 in the acidic form showed intermediate activities between patients and control subjects. In neutral conditions, pH 6.0, the PPT1 enzyme activities in NCL 1 patients showed rather higher residual activities and intermediate activities in heterozygotes in NCL 1, which was probably caused by mutated proteins in three cases with NCL 1 patients. TPP1 enzyme activities at neutral pH 6.5 to 7.0 in DBS and leukocytes/lymphocytes showed higher enzyme activities in NCL 2 patients and heterozygotes. The reason for the increases of neutral TPP1 enzyme activities at pH 6.5 to 7.0 in NCL 2 DBS and leukocytes/lymphocytes, is obscure, but possibly caused by secondary activation of neutral TPP1 enzyme due to the absence of the acidic form. Interestingly, TPP1 activity in serum only consisted of a neutral form, no acidic form, and was not deficient in any NCL 2 patient. Therefore, we can diagnose NCL 1 patients by plasma/serum enzyme assay of PPT1, but not diagnose NCL 2 by serum TPP1 enzyme assay. A pilot study of newborn screening of NCL 1 and 2 has been established by more than 1000 newborn DBS assays. Using this assay system, we will be able to perform newborn screening of NCL 1 and 2 by DBS.

A Case of Adult-onset Pompe Disease with Cerebral Stroke and Left Ventricular Hypertrophy

BACKGROUND Pompe disease is an autosomal recessive glycogen storage disorder caused by a deficiency of the lysosomal glycogen-hydrolyzing enzyme acid α-glucosidase. The adult-onset form, late-onset Pompe disease, has been characterized by glycogen accumulation, primarily in skeletal and smooth muscles, causing weakness of the proximal limb girdle and respiratory compromises. CASE REPORT A 59-year-old female was admitted to the hospital with acute cerebral stroke at the age of 57years. Following her admission, conventional conservative stroke management followed by cerebral arterial clipping was performed. However, weakness of lower extremities, predominantly in the right side, and evening headache were persisting. After obtaining a careful past history, she noticed that she had a history of recurrent respiratory tract infection and she did not like any physical exercise in school. She also complained of gait disturbance since 32years of age. She had also been suffering from systemic hypertension since 40years of age. She had mild respiratory and swallowing difficulties. Her brain Magnetic Resonance (MR) revealed multiple infractions and white matter degeneration with irregular basilar arterial walls. A computed tomography (CT) scan of lower extremities showed diffuse fibrosis of the proximal muscles predominantly on the right thigh. Cardiac echocardiogram showed left ventricular hypertrophy. Electron microscopy of blood cells including lymphocytes and platelets and skin fibroblasts showed marked granular inclusions in lysosomes, suggesting glycogen accumulation. Her measured acid α-glucosidase activity was very low, 1.3 pmol hour-1 punch-1, and we found a homozygous splice-site mutation c.546G>T in the GAA gene. CONCLUSION Cerebral stoke as an initial finding for an adult-type Pompe disease is rare. Left ventricular hypertrophy is also rarely reported for adult onset of Pompe disease. This case will explore further ways to diagnose adult-onset Pompe disease.

L-leucine and SPNS1 coordinately ameliorate dysfunction of autophagy in mouse and human Niemann-Pick type C disease

Lysosomal storage disorders are characterized by progressive accumulation of undigested macromolecules within the cell due to lysosomal dysfunction. 573C10 is a Schwann cell line derived from a mouse model of Niemann-Pick type C disease-1, NPC (−/−). Under serum-starved conditions, NPC (−/−) cells manifested impaired autophagy accompanied by an increase in the amount of p62 and lysosome enlargement. Addition of L-leucine to serum-starved NPC (−/−) cells ameliorated the enlargement of lysosomes and the p62 accumulation. Similar autophagy defects were observed in NPC (−/−) cells even without serum starvation upon the knockdown of Spinster-like 1 (SPNS1), a putative transporter protein thought to function in lysosomal recycling. Conversely, SPNS1 overexpression impeded the enlargement of lysosomes, p62 accumulation and mislocalization of the phosphorylated form of the mechanistic Target of rapamycin in NPC (−/−) cells. In addition, we found a reduction in endogenous SPNS1 expression in fibroblasts derived from NPC-1 patients compared with normal fibroblasts. We propose that SPNS1-dependent L-leucine export across the lysosomal membrane is a key step for triggering autophagy, and that this mechanism is impaired in NPC-1.