Gene therapy corrects the neurological deficits of mice with sialidosis.

Patients with sialidosis (mucolipidosis type I) type I typically present with myoclonus, seizures, ataxia, cherry-red spots, and blindness because of mutations in the neuraminidase 1 (NEU1) gene. Currently, there is no treatment for sialidosis. In this study, we developed an adeno-associated virus (AAV)-mediated gene therapy for a Neu1 knockout (Neu1-/-) mouse model of sialidosis. The vector, AAV9-P3-NP, included the human NEU1 promoter, NEU1 cDNA, IRES, and CTSA cDNA. Untreated Neu1-/- mice showed astrogliosis and microglial LAMP1 accumulation in the nervous system, including brain, spinal cord, and dorsal root ganglion, together with impaired motor function. Coexpression of NEU1 and protective protein/cathepsin A (PPCA) in neonatal Neu1-/- mice by intracerebroventricular injection, and less effective by facial vein injection, decreased astrogliosis and LAMP1 accumulation in the nervous system and improved rotarod performance of the treated mice. Facial vein injection also improved the grip strength and survival of Neu1-/- mice. Therefore, cerebrospinal fluid delivery of AAV9-P3-NP, which corrects the neurological deficits of mice with sialidosis, could be a suitable treatment for patients with sialidosis type I. After intracerebroventricular or facial vein injection of AAV vectors, NEU1 and PPCA are expressed together. PPCA-protected NEU1 is then sent to lysosomes, where ß-Gal binds to this complex to form a multienzyme complex in order to execute its function.

Nigrostriatal tract defects in mice with aromatic l-amino acid decarboxylase deficiency.

The development of the nigrostriatal dopaminergic (DA) pathway in the brain involves many transcriptional and chemotactic molecules, and a deficiency of these molecules can cause nigrostriatal tract defects. However, the role of the end product, dopamine, in nigrostriatal pathway development has not been described. In the present study, we analyzed a mouse model of congenital dopamine and serotonin deficiency, namely, the aromatic l-amino acid decarboxylase (AADC) deficiency (DdcKI) mouse model. We found via tyrosine hydroxylase (TH) immunofluorescence staining that the number of DA fibers in the stratum of 14-day-old DdcKI mice decreased. In TH-stained cleared whole brains of DdcKI mice, the numbers of DA neurons in the substantia nigra (SN) and the number of DA nerve bundles leaving the SN were both normal. However, we found that the nigrostriatal bundles in DdcKI mice were dispersed, taking aberrant routes to the striatum and spreading over a wide area. The total volume occupied by the nigrostriatal tract was increased, and the fraction of TH staining in the tract was decreased in DdcKI mice. Single-nucleus RNA sequencing analysis for mice 0, 7, and 14 days of age, revealed delayed axonogenesis and synapse formation in the striatum of DdcKI mice. The CellChat program inferred less cell-cell communication between striatal D1/D2 neurons but increased cell-cell communication involving neural precursors in DdcKI mice. Therefore, a congenital deficiency in dopamine affects nigrostriatal axon extension and striatal innervation. These nigrostriatal tract defects may limit the treatment efficacy for patients with TH or AADC deficiency.

Loss of Flot2 expression in deep cerebellar nuclei neurons of mice with Niemann-Pick disease type C.

Niemann-Pick disease type C (NPC) is caused by a deficiency of the NPC1 or NPC2 gene, leading to storages of unesterified cholesterol and sphingolipids. Cerebellar ataxia is a main symptom of NPC and the deep cerebellar nuclei (DCN) is the sole signal output of the cerebellum. In this study, we explored the pathological changes in DCN neurons of Npc1 knockout mice (Npc1-). We first demonstrated that DCN neurons of Npc1- mice had prominent ganglioside GM2 accumulation in the late endosomes but not in the lysosomes. More importantly, Flot2 expression, a marker for the lipid rafts, was lost. Single-nucleus RNA sequencing analysis revealed a generalized reduction in gene expression in DCN neurons, though Camk1d, encoding one of the Ca2+/calmodulin-dependent protein kinases (CaMKs), increased in expression. We treated Npc1- mice with CaMK inhibitor KN-93, but CaMK1D expression increased further. We also fed Npc1- mice with two medications for NPC. We found that miglustat, a sphingolipid synthesis inhibitor, increased the expression of Flot2. Moreover, N-acetyl l-leucine (NALL), an experimental medicine for NPC, recovered Flot2 expression. Therefore, our data suggest that in Npc1- mice, GM2 sequestration and the loss of lipid rafts lead to cell dysfunction and symptoms of NPC.

[Studying the therapeutic effects of hemoperfusion with continuous venovenous hemofiltration on the patients with acute paraquat poisoning].

OBJECTIVE: To explore the therapeutic effects of hemoperfusion (HP) with continuous venovenous hemofiltration (CVVH) on the patients with acute paraquat poisoning. METHODS: Ninety-one patients with acute paraquat poisoning were randomly divided into HP group (49 cases) and HP-CVVH group (42 cases). The mortality, survival duration and the death causes between the two groups were compared and analyzed. RESULTS: There were no significant differences in mortality (59.2% versus 61.9%) between the two groups. The mean time between poisoning and death in HP-CVVH group was (4.9 +/- 3.1) days, which was significantly longer than that (3.5 +/- 2.0) days in HP group (P < 0.05). The death proportion on 4th day after poisoning in HP group was 62.1% (18/29), which was significantly higher than that (30.8%, 8/26) in HP-CVVH group (P < 0.05). The hypoxia appeared in 4.3 +/- 2.5 days after poisoning in HP-CVVH group, which was significantly longer than that (3.2 +/- 1.9) days in HP group (P < 0.05). The mortality due to respiratory failure in HP group was 20.4% (10/49), which was significantly lower than that (40.5%, 17/42) in HP-CVVH group (P < 0.05). The incidence of acute renal failure in HP group was 63.3% (31/49), which was significantly higher than that (40.5%, 17/42) in HP-CVVH group (P < 0.05). CONCLUSION: The combined therapy of HP and CVVH can prevent the patients with acute paraquat poisoning from early death and prolong the survival duration, but can not reduce mortality for the patients with acute paraquat poisoning.

[Study on the prognosis of patients with acute paraquat intoxication].

OBJECTIVE: To study the correlation factors of acute paraquat intoxication prognosis. METHODS: The early paraquat concentration in plasma and urine, leukocyte count, hepatic and renal function, amylase, electrolyte and the parameters of arterial blood gas were analyzed retrospectively in 111 patients with acute paraquat intoxication. RESULTS: 43 cases (38.7%) of all the 111 patients survived and the other 68 cases (61.3%) died. The patient, whose paraquat concentration was not more than 8.0 µg/ml in plasma and 276.0 µg/ml in urine, could survive. But some patients could die, only if there was no paraquat found in plasma. The paraquat levels in plasma and urine were significantly lower in survivors [(0.82 ± 1.70), (28.12 ± 51.17) µg/ml] than in nonsurvivors [(9.32 ± 12.04), (384.53 ± 597.93) µg/ml, respectively] (P < 0.01). The levels of leukocyte count, serum creatinine, aspartate aminotransferase (AST), and amylase were significantly higher in nonsurvivors than in survivors (P < 0.05, P < 0.01). In addition, metabolic acidosis was easier to appear in nonsurvivors. The multiple logistic regression analysis indicated that the paraquat concentration in plasma and urine, leukocyte count, creatinine and base excess were all related to survival. CONCLUSION: The higher paraquat concentration in plasma and urine, leucocytosis, renal dysfunction and metabolic acidosis are all important factors for the prognosis of paraquat intoxication.

Ultrastructural and diffusion tensor imaging studies reveal axon abnormalities in Pompe disease mice.

Pompe disease (PD) is caused by lysosomal glycogen accumulation in tissues, including muscles and the central nervous system (CNS). The intravenous infusion of recombinant human acid alpha-glucosidase (rhGAA) rescues the muscle pathologies in PD but does not treat the CNS because rhGAA does not cross the blood-brain barrier (BBB). To understand the CNS pathologies in PD, control and PD mice were followed and analyzed at 9 and 18 months with brain structural and ultrastructural studies. T2-weighted brain magnetic resonance imaging studies revealed the progressive dilatation of the lateral ventricles and thinning of the corpus callosum in PD mice. Electron microscopy (EM) studies at the genu of the corpus callosum revealed glycogen accumulation, an increase in nerve fiber size variation, a decrease in the g-ratio (axon diameter/total fiber diameter), and myelin sheath decompaction. The morphology of oligodendrocytes was normal. Diffusion tensor imaging (DTI) studies at the corpus callosum revealed an increase in axial diffusivity (AD) and mean diffusivity (MD) more significantly in 9-month-old PD mice. The current study suggests that axon degeneration and axon loss occur in aged PD mice and are probably caused by glycogen accumulation in neurons. A drug crossing the BBB or a treatment for directly targeting the brain might be necessary in PD.

Variant R244H in Na+/Mg2+ exchanger SLC41A1 in Taiwanese Parkinson's disease is associated with loss of Mg2+ efflux function.

BACKGROUND: Sequence variants in SLC41A1 have been reported to be associated with Parkinson's disease (PD). This study investigates whether the genetic variants in SLC41A1 contribute to Taiwanese PD. METHODS: We sequenced SLC41A1 cDNA fragments from 80 patients with early onset PD. A cohort of PD and ethnically matched controls were examined for the sequence variant. The effect of variation on Mg(2+) homeostasis was further examined using stably induced 293 cells expressing recombinant wild type and variant SLC41A1. RESULTS: A novel heterozygous R244H in the SLC41A1 gene was identified in one early onset PD patient, which not present either in 479 PD patients or 525 normal controls with age onset >50. Both wild type and R244H SLC41A1-V5-His proteins were co-localized to areas of the plasma membrane that were stained using wheat germ agglutinin (WGA). Fluorescent probe mag-fluo-4 staining indicated that R244H SLC41A1 is dysfunctional in Mg(2+) efflux. CONCLUSIONS: This study has shown loss of Mg(2+) efflux function consequent to SLC41A1 R244H variant and SLC41A1 coding variants seem to be rare in Taiwanese PD.

Role of the CCAAT-binding protein NFY in SCA17 pathogenesis.

Spinocerebellar ataxia 17 (SCA17) is caused by expansion of the polyglutamine (polyQ) tract in human TATA-box binding protein (TBP) that is ubiquitously expressed in both central nervous system and peripheral tissues. The spectrum of SCA17 clinical presentation is broad. The precise pathogenic mechanism in SCA17 remains unclear. Previously proteomics study using a cellular model of SCA17 has revealed reduced expression of heat shock 70 kDa protein 5 (HSPA5) and heat shock 70 kDa protein 8 (HSPA8), suggesting that impaired protein folding may contribute to the cell dysfunction of SCA17 (Lee et al., 2009). In lymphoblastoid cells, HSPA5 and HSPA8 expression levels in cells with mutant TBP were also significantly lower than that of the control cells (Chen et al., 2010). As nuclear transcription factor Y (NFY) has been reported to regulate HSPA5 transcription, we focused on if NFY activity and HSPA5 expression in SCA17 cells are altered. Here, we show that TBP interacts with NFY subunit A (NFYA) in HEK-293 cells and NFYA incorporated into mutant TBP aggregates. In both HEK-293 and SH-SY5Y cells expressing TBP/Q(61~79), the level of soluble NFYA was significantly reduced. In vitro binding assay revealed that the interaction between TBP and NFYA is direct. HSPA5 luciferase reporter assay and endogenous HSPA5 expression analysis in NFYA cDNA and siRNA transfection cells further clarified the important role of NFYA in regulating HSPA5 transcription. In SCA17 cells, HSPA5 promoter activity was activated as a compensatory response before aggregate formation. NFYA dysfunction was indicated in SCA17 cells as HSPA5 promoter activity reduced along with TBP aggregate formation. Because essential roles of HSPA5 in protection from neuronal apoptosis have been shown in a mouse model, NFYA could be a target of mutant TBP in SCA17.