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1.
Acta Neuropathol Commun ; 12(1): 20, 2024 Feb 04.
Article En | MEDLINE | ID: mdl-38311779

The abnormal aggregation of TDP-43 into cytoplasmic inclusions in affected neurons is a major pathological hallmark of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Although TDP-43 is aberrantly accumulated in the neurons of most patients with sporadic ALS/FTD and other TDP-43 proteinopathies, how TDP-43 forms cytoplasmic aggregates remains unknown. In this study, we show that a deficiency in DCTN1, a subunit of the microtubule-associated motor protein complex dynactin, perturbs the dynamics of stress granules and drives the formation of TDP-43 cytoplasmic aggregation in cultured cells, leading to the exacerbation of TDP-43 pathology and neurodegeneration in vivo. We demonstrated using a Drosophila model of ALS/FTD that genetic knockdown of DCTN1 accelerates the formation of ubiquitin-positive cytoplasmic inclusions of TDP-43. Knockdown of components of other microtubule-associated motor protein complexes, including dynein and kinesin, also increased the formation of TDP-43 inclusions, indicating that intracellular transport along microtubules plays a key role in TDP-43 pathology. Notably, DCTN1 knockdown delayed the disassembly of stress granules in stressed cells, leading to an increase in the formation of pathological cytoplasmic inclusions of TDP-43. Our results indicate that a deficiency in DCTN1, as well as disruption of intracellular transport along microtubules, is a modifier that drives the formation of TDP-43 pathology through the dysregulation of stress granule dynamics.


Amyotrophic Lateral Sclerosis , DNA-Binding Proteins , Drosophila Proteins , Dynactin Complex , Frontotemporal Dementia , Animals , Humans , Amyotrophic Lateral Sclerosis/pathology , DNA-Binding Proteins/genetics , DNA-Binding Proteins/metabolism , Drosophila/metabolism , Dynactin Complex/genetics , Frontotemporal Dementia/pathology , Stress Granules , Drosophila Proteins/genetics
2.
Biol Pharm Bull ; 46(8): 1049-1056, 2023.
Article En | MEDLINE | ID: mdl-37532556

Bortezomib, an anticancer drug for multiple myeloma and mantle cell lymphoma, causes severe adverse events and leads to peripheral neuropathy. The associated neuropathy limits the use of bortezomib and could lead to discontinuation of the treatment; therefore, effective intervention is crucial. In the present study, we statistically searched for a drug that could alleviate bortezomib-induced peripheral neuropathy using adverse event self-reports. We observed that specific inhibitors of the mechanistic target of rapamycin (mTOR) lowered the incidence of bortezomib-induced peripheral neuropathy. These findings were experimentally validated in mice, which exhibited long-lasting mechanical hypersensitivity after repeated bortezomib treatment. This effect was inhibited for hours after a systemic injection with rapamycin or everolimus in a dose-dependent manner. Bortezomib-induced allodynia was accompanied by the activation of spinal astrocytes, and intrathecal injection of mTOR inhibitors or an inhibitor of ribosomal protein S6 kinase 1, a downstream target of mTOR, exhibited considerable analgesic effects in a dose-dependent manner. These results suggest that mTOR inhibitors, which are readily available to patients prescribed bortezomib, are one of the most effective therapeutics for bortezomib-induced peripheral neuropathy.


Antineoplastic Agents , Bortezomib , Peripheral Nervous System Diseases , Animals , Mice , Antineoplastic Agents/adverse effects , Bortezomib/adverse effects , MTOR Inhibitors , Peripheral Nervous System Diseases/chemically induced , Peripheral Nervous System Diseases/drug therapy , Peripheral Nervous System Diseases/metabolism , Sirolimus/pharmacology , TOR Serine-Threonine Kinases/metabolism
3.
iScience ; 26(6): 106997, 2023 Jun 16.
Article En | MEDLINE | ID: mdl-37378316

Diabetic peripheral neuropathy (DPN) is the most common chronic, progressive complication of diabetes mellitus. The main symptom is sensory loss; the molecular mechanisms are not fully understood. We found that Drosophila fed a high-sugar diet, which induces diabetes-like phenotypes, exhibit impairment of noxious heat avoidance. The impairment of heat avoidance was associated with shrinkage of the leg neurons expressing the Drosophila transient receptor potential channel Painless. Using a candidate genetic screening approach, we identified proteasome modulator 9 as one of the modulators of impairment of heat avoidance. We further showed that proteasome inhibition in the glia reversed the impairment of noxious heat avoidance, and heat-shock proteins and endolysosomal trafficking in the glia mediated the effect of proteasome inhibition. Our results establish Drosophila as a useful system for exploring molecular mechanisms of diet-induced peripheral neuropathy and propose that the glial proteasome is one of the candidate therapeutic targets for DPN.

5.
Genet Med ; 25(2): 100335, 2023 02.
Article En | MEDLINE | ID: mdl-36507973

The U.S. Food and Drug Administration recently approved lonafarnib as the first treatment for Hutchinson-Gilford progeria syndrome (HGPS) and processing-deficient progeroid laminopathies. This approval was primarily based on a comparison of patients with HGPS treated with lonafarnib in 2 open-label trials with an untreated patient cohort. With up to 11 years of follow-up, it was found that the lonafarnib treated patients with HGPS had a survival benefit of 2.5 years compared with the untreated patients with HGPS. This large treatment effect on the objective endpoint of mortality using a well-matched comparator group mitigated potential sources of bias and together with other evidence, established compelling evidence of a drug effect with benefits that outweighed the risks. This approval is an example of U.S. Food and Drug Administration's regulatory flexibility for a rare disease while ensuring that standards for drug approval are met.


Progeria , United States , Humans , Progeria/drug therapy , Progeria/genetics , Lamin Type A/genetics , Piperidines/therapeutic use , Pyridines/therapeutic use
6.
Lancet Diabetes Endocrinol ; 10(7): 499-508, 2022 07.
Article En | MEDLINE | ID: mdl-35533704

BACKGROUND: The association between cortisol secretion and mortality in patients with adrenal incidentalomas is controversial. We aimed to assess all-cause mortality, prevalence of comorbidities, and occurrence of cardiovascular events in uniformly stratified patients with adrenal incidentalomas and cortisol autonomy (defined as non-suppressible serum cortisol on dexamethasone suppression testing). METHODS: We conducted an international, retrospective, cohort study (NAPACA Outcome) at 30 centres in 16 countries. Eligible patients were aged 18 years or older with an adrenal incidentaloma (diameter ≥1 cm) detected between Jan 1, 1996, and Dec 31, 2015, and availability of a 1 mg dexamethasone suppression test result from the time of the initial diagnosis. Patients with clinically apparent hormone excess, active malignancy, or follow-up of less than 36 months were excluded. Patients were stratified according to the 0800-0900 h serum cortisol values after an overnight 1 mg dexamethasone suppression test; less than 50 nmol/L was classed as non-functioning adenoma, 50-138 nmol/L as possible autonomous cortisol secretion, and greater than 138 nmol/L as autonomous cortisol secretion. The primary endpoint was all-cause mortality. Secondary endpoints were the prevalence of cardiometabolic comorbidities, cardiovascular events, and cause-specific mortality. The primary and secondary endpoints were assessed in all study participants. FINDINGS: Of 4374 potentially eligible patients, 3656 (2089 [57·1%] with non-functioning adenoma, 1320 [36·1%] with possible autonomous cortisol secretion, and 247 [6·8%] with autonomous cortisol secretion) were included in the study cohort for mortality analysis (2350 [64·3%] women and 1306 [35·7%] men; median age 61 years [IQR 53-68]; median follow-up 7·0 years [IQR 4·7-10·2]). During follow-up, 352 (9·6%) patients died. All-cause mortality (adjusted for age, sex, comorbidities, and previous cardiovascular events) was significantly increased in patients with possible autonomous cortisol secretion (HR 1·52, 95% CI 1·19-1·94) and autonomous cortisol secretion (1·77, 1·20-2·62) compared with patients with non-functioning adenoma. In women younger than 65 years, autonomous cortisol secretion was associated with higher all-cause mortality than non-functioning adenoma (HR 4·39, 95% CI 1·93-9·96), although this was not observed in men. Cardiometabolic comorbidities were significantly less frequent with non-functioning adenoma than with possible autonomous cortisol secretion and autonomous cortisol secretion (hypertension occurred in 1186 [58·6%] of 2024 patients with non-functioning adenoma, 944 [74·0%] of 1275 with possible autonomous cortisol secretion, and 179 [75·2%] of 238 with autonomous cortisol secretion; dyslipidaemia occurred in 724 [36·2%] of 1999 patients, 547 [43·8%] of 1250, and 123 [51·9%] of 237; and any diabetes occurred in 365 [18·2%] of 2002, 288 [23·0%] of 1250, and 62 [26·7%] of 232; all p values <0·001). INTERPRETATION: Cortisol autonomy is associated with increased all-cause mortality, particularly in women younger than 65 years. However, until results from randomised interventional trials are available, a conservative therapeutic approach seems to be justified in most patients with adrenal incidentaloma. FUNDING: Deutsche Forschungsgemeinschaft, Associazione Italiana per la Ricerca sul Cancro, Università di Torino.


Adenoma , Adrenal Gland Neoplasms , Hypertension , Adenoma/complications , Adrenal Gland Neoplasms/complications , Adrenal Gland Neoplasms/epidemiology , Cohort Studies , Dexamethasone , Female , Humans , Hydrocortisone , Hypertension/complications , Male , Middle Aged , Retrospective Studies
7.
Int J Mol Sci ; 23(3)2022 Jan 28.
Article En | MEDLINE | ID: mdl-35163450

α-Synuclein (αSyn) plays a major role in the pathogenesis of Parkinson's disease (PD), which is the second most common neurodegenerative disease after Alzheimer's disease. The accumulation of αSyn is a pathological hallmark of PD, and mutations in the SNCA gene encoding αSyn cause familial forms of PD. Moreover, the ectopic expression of αSyn has been demonstrated to mimic several key aspects of PD in experimental model systems. Among the various model systems, Drosophila melanogaster has several advantages for modeling human neurodegenerative diseases. Drosophila has a well-defined nervous system, and numerous tools have been established for its genetic analyses. The rapid generation cycle and short lifespan of Drosophila renders them suitable for high-throughput analyses. PD model flies expressing αSyn have contributed to our understanding of the roles of various disease-associated factors, including genetic and nongenetic factors, in the pathogenesis of PD. In this review, we summarize the molecular pathomechanisms revealed to date using αSyn-expressing Drosophila models of PD, and discuss the possibilities of using these models to demonstrate the biological significance of disease-associated factors.


Mutation , Parkinson Disease/genetics , alpha-Synuclein/genetics , Animals , Animals, Genetically Modified , Disease Models, Animal , Drosophila melanogaster/genetics , Drosophila melanogaster/growth & development , Humans , Parkinson Disease/metabolism , alpha-Synuclein/metabolism
8.
Data Brief ; 37: 107222, 2021 Aug.
Article En | MEDLINE | ID: mdl-34189208

The accumulation of pathogenic misfolded proteins is believed to be a common mechanism of generation of neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, and polyglutamine (polyQ) diseases. The autophagy-lysosome degradation system has been considered as a potential therapeutic target against these disorders, as it is able to degrade large protein aggregates. Previously, we focused on Rubicon, a negative regulator of autophagy, and demonstrated that knockdown of the Drosophila homolog of Rubicon (dRubicon) suppressed locomotor dysfunction in a fly model of polyQ disease. This suppression was associated with increased autophagic activity and a marked reduction in the number of polyQ inclusion bodies [1]. We generated transgenic fly lines expressing hemagglutinin-tagged dRubicon wild-type (WT) or dRubicon in which the RUN [after RPIP8 (RaP2 interacting protein 8), UNC-14 and NESCA (new molecule containing SH3 at the carboxyl-terminus)] domain was deleted (ΔRUN). We provide data regarding the effect of WT and ΔRUN dRubicon co-expression on polyQ-induced locomotor dysfunction in Drosophila.

9.
BMC Biol ; 19(1): 43, 2021 03 11.
Article En | MEDLINE | ID: mdl-33706787

BACKGROUND: Amyloids are ordered, insoluble protein aggregates, characterized by a cross-ß sheet quaternary structure in which molecules in a ß-strand conformation are stacked along the filament axis via intermolecular interactions. While amyloids are typically associated with pathological conditions, functional amyloids have also been identified and are present in a wide variety of organisms ranging from bacteria to humans. The cytoplasmic polyadenylation element-binding (CPEB) prion-like protein is an mRNA-binding translation regulator, whose neuronal isoforms undergo activity-dependent aggregation, a process that has emerged as a plausible biochemical substrate for memory maintenance. CPEB aggregation is driven by prion-like domains (PLD) that are divergent in sequence across species, and it remains unknown whether such divergent PLDs follow a similar aggregating assembly pathway. Here, we describe the amyloid-like features of the neuronal Aplysia CPEB (ApCPEB) PLD and compare them to those of the Drosophila ortholog, Orb2 PLD. RESULTS: Using in vitro single-molecule and bulk biophysical methods, we find transient oligomers and mature amyloid-like filaments that suggest similarities in the late stages of the assembly pathway for both ApCPEB and Orb2 PLDs. However, while prior to aggregation the Orb2 PLD monomer remains mainly as a random coil in solution, ApCPEB PLD adopts a diversity of conformations comprising α-helical structures that evolve to coiled-coil species, indicating structural differences at the beginning of their amyloid assembly pathways. CONCLUSION: Our results indicate that divergent PLDs of CPEB proteins from different species retain the ability to form a generic amyloid-like fold through different assembly mechanisms.


Amyloid/metabolism , Aplysia/metabolism , Prions/metabolism , Animals , Aplysia/chemistry , Polyadenylation , Prions/chemistry
10.
Endocrine ; 72(1): 96-103, 2021 04.
Article En | MEDLINE | ID: mdl-33462741

BACKGROUND: Primary aldosteronism (PA) is associated with an increased risk for dysglycemia. However, the effects of hyperaldosteronism on insulin sensitivity and ß-cell function are unclear. METHODS: Using a cross-sectional study design, we assessed insulin sensitivity and pancreatic ß-cell function from an oral glucose tolerance test (OGTT) in patients from two cohorts: subjects with PA (n = 21) and essential hypertension control (EHC) subjects (n = 22). Age, sex, BMI, and mean arterial pressure adjusted measures of insulin sensitivity and ß-cell function were compared between the groups. RESULTS: PA individuals were less insulin sensitive compared to EHC subjects (Quantitative insulin sensitivity check index [QUICKI]: 0.340 ± 0.006 vs. 0.374 ± 0.013, p < 0.001; Matsuda index: 4.14 ± 0.49 vs. 7.87 ± 1.42, p < 0.001; SI: 11.45 ± 4.85 vs. 21.23 ± 6.11 dL/kg/min per µU/mL, p = 0.02). The hepatic insulin resistance index (HIRI) was higher in PA subjects (PA: 5.61 ± 1.01 vs. EHC: 4.13 ± 0.61, p = 0.002). The insulinogenic index (IGI), an index of ß-cell function was higher in the PA cohort (PA: 1.49 ± 0.27 vs. 1.11 ± 0.21 µU/mL/mg/dL, p = 0.03). However, the oral disposition index (DI) was similar between the groups (PA: 4.77 ± 0.73 vs. EHC: 5.46 ± 0.85, p = 0.42), which likely accounts for the similar glucose tolerance between the two cohorts, despite lower sensitivity. CONCLUSIONS: In summary, insulin sensitivity is significantly lower in PA with an appropriately compensated ß-cell function. These results suggest that excess aldosterone and/or other steroids in the context of PA may negatively affect insulin action without adversely impacting ß-cell function.


Hyperaldosteronism , Insulin Resistance , Insulin-Secreting Cells , Blood Glucose , Cross-Sectional Studies , Glucose Tolerance Test , Humans , Insulin
11.
Brain ; 143(6): 1811-1825, 2020 06 01.
Article En | MEDLINE | ID: mdl-32436573

The polyglutamine (polyQ) diseases are a group of inherited neurodegenerative diseases that include Huntington's disease, various spinocerebellar ataxias, spinal and bulbar muscular atrophy, and dentatorubral pallidoluysian atrophy. They are caused by the abnormal expansion of a CAG repeat coding for the polyQ stretch in the causative gene of each disease. The expanded polyQ stretches trigger abnormal ß-sheet conformational transition and oligomerization followed by aggregation of the polyQ proteins in the affected neurons, leading to neuronal toxicity and neurodegeneration. Disease-modifying therapies that attenuate both symptoms and molecular pathogenesis of polyQ diseases remain an unmet clinical need. Here we identified arginine, a chemical chaperone that facilitates proper protein folding, as a novel compound that targets the upstream processes of polyQ protein aggregation by stabilizing the polyQ protein conformation. We first screened representative chemical chaperones using an in vitro polyQ aggregation assay, and identified arginine as a potent polyQ aggregation inhibitor. Our in vitro and cellular assays revealed that arginine exerts its anti-aggregation property by inhibiting the toxic ß-sheet conformational transition and oligomerization of polyQ proteins before the formation of insoluble aggregates. Arginine exhibited therapeutic effects on neurological symptoms and protein aggregation pathology in Caenorhabditis elegans, Drosophila, and two different mouse models of polyQ diseases. Arginine was also effective in a polyQ mouse model when administered after symptom onset. As arginine has been safely used for urea cycle defects and for mitochondrial myopathy, encephalopathy, lactic acid and stroke syndrome patients, and efficiently crosses the blood-brain barrier, a drug-repositioning approach for arginine would enable prompt clinical application as a promising disease-modifier drug for the polyQ diseases.


Arginine/metabolism , Arginine/pharmacology , Peptides/metabolism , Animals , Caenorhabditis elegans/metabolism , Disease Models, Animal , Drosophila/metabolism , Female , Heredodegenerative Disorders, Nervous System/genetics , Huntington Disease/genetics , Male , Mice , Mice, Inbred Strains , Molecular Chaperones/genetics , Peptides/genetics , Protein Aggregation, Pathological , Protein Conformation/drug effects , Protein Folding/drug effects , Spinocerebellar Ataxias/genetics
12.
Am J Hypertens ; 33(2): 124-130, 2020 02 22.
Article En | MEDLINE | ID: mdl-31637427

BACKGROUND: Somatic variants in KCNJ5 are the most common cause of primary aldosteronism (PA). There are few patients with PA in whom the disease is caused by germline variants in the KCNJ5 potassium channel gene (familial hyperaldosteronism type III-FH-III). METHODS: A 5-year-old patient who developed hypertension due to bilateral adrenocortical hyperplasia (BAH) causing PA had negative peripheral DNA testing for any known genetic causes of PA. He was treated medically with adequate control of his PA but by the third decade of his life, due to worsening renal function, he underwent bilateral adrenalectomy. RESULTS: Focused exome sequencing in multiple nodules of his BAH uncovered a "hot-spot" pathogenic KCNJ5 variant, while repeated Sanger sequencing showed no detectable DNA defects in peripheral blood and other tissues. However, whole exome, "deep" sequencing revealed that 0.23% of copies of germline DNA did in fact carry the same KCNJ5 variant that was present in the adrenocortical nodules, suggesting low level germline mosaicism for this PA-causing KCNJ5 defect. CONCLUSIONS: Thus, this patient represents a unique case of BAH due to a mosaic KCNJ5 defect. Undoubtedly, his milder PA compared with other known cases of FH-III, was due to his mosaicism. This case has a number of implications for the prognosis, treatment, and counseling of the many patients with PA due to BAH that are seen in hypertension clinics.


Adrenal Cortex/pathology , G Protein-Coupled Inwardly-Rectifying Potassium Channels/genetics , Hyperaldosteronism/genetics , Mosaicism , Adrenal Cortex/surgery , Adrenalectomy , Child, Preschool , Genetic Predisposition to Disease , Humans , Hyperaldosteronism/diagnosis , Hyperaldosteronism/surgery , Hyperplasia , Male , Phenotype , Treatment Outcome
13.
Histochem Cell Biol ; 153(2): 111-119, 2020 Feb.
Article En | MEDLINE | ID: mdl-31734714

Glycolaldehyde (GA) is a highly reactive hydroxyaldehyde and one of the glycolytic metabolites producing advanced glycation endproducts (AGEs), but its toxicity toward neurons and Schwann cells remains unclear. In the present study, we found that GA exhibited more potent toxicity than other AGE precursors (glyceraldehyde, glyoxal, methylglyoxal and 3-deoxyglucosone) against immortalized IFRS1 adult rat Schwann cells and ND7/23 neuroblastoma × neonatal rat dorsal root ganglion (DRG) neuron hybrid cells. GA affected adult rat DRG neurons and ND7/23 cells more severely than GA-derived AGEs, and exhibited concentration- and time-dependent toxicity toward ND7/23 cells (10 < 100 < 250 < 500 µM; 6 h < 24 h). Treatment with 500 µM GA significantly up-regulated the phosphorylation of c-jun N-terminal kinase (JNK) and p-38 mitogen-activated kinase (p-38 MAPK) in ND7/23 cells. Furthermore, GA-induced ND7/23 cell death was significantly inhibited due to co-treatment with 10 µM of the JNK inhibitor SP600125 or the p-38 MAPK inhibitor SB239063. These findings suggest the involvement of JNK and p-38 MAPK-signaling pathways in GA-induced neuronal cell death and that enhanced GA production under diabetic conditions might be involved in the pathogenesis of diabetic neuropathy.


Acetaldehyde/analogs & derivatives , JNK Mitogen-Activated Protein Kinases/metabolism , Sensory Receptor Cells/drug effects , Signal Transduction/drug effects , p38 Mitogen-Activated Protein Kinases/metabolism , Acetaldehyde/pharmacology , Animals , Cell Death/drug effects , Cells, Cultured , Enzyme Activation/drug effects , Female , Rats , Rats, Wistar , Sensory Receptor Cells/metabolism
14.
Article En | MEDLINE | ID: mdl-31480016

SUMMARY: Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant condition characterized by parathyroid, anterior pituitary and enteropancreatic endocrine cell tumors. Neuroendocrine tumors occur in approximately in 5-15% of MEN1 patients. Very few cases of ovarian NETs have been reported in association with clinical MEN1 and without genetic testing confirmation. Thirty-three-year-old woman with MEN1 was found to have right adnexal mass on computed tomography (CT). Attempt at laparoscopic removal was unsuccessful, and mass was removed via a minilaparotomy in piecemeal fashion. Pathology showed ovarian NET arising from a teratoma. Four years later, patient presented with recurrence involving the pelvis and anterior abdominal wall. She was treated with debulking surgery and somatostatin analogs (SSAs). Targeted DNA sequencing analysis on the primary adnexal mass as well as the recurrent abdominal wall tumor confirmed loss of heterozygosity (LOH) at the MEN1 gene locus. This case represents to our knowledge, the first genetically confirmed case of ovarian NET arising by a MEN1 mechanism in a patient with MEN1. Extreme caution should be exercised during surgery as failure to remove an ovarian NET en masse can result in peritoneal seeding and recurrence. For patients with advanced ovarian NETs, systemic therapy options include SSAs, peptide receptor radioligand therapy (PRRT) and novel agents targeting mammalian target of rapamycin (mTOR) and vascular endothelial growth factor (VEGF). LEARNING POINTS: Ovarian NET can arise from a MEN1 mechanism, and any adnexal mass in a MEN1 patient can be considered as a possible malignant NET. Given the rarity of this disease, limited data are available on prognostication and treatment. Management strategies are extrapolated from evidence available in NETs from primaries of other origins. Care should be exercised to remove ovarian NETs en bloc as failure to do so may result in peritoneal seeding and recurrence. Treatment options for advanced disease include debulking surgery, SSAs, TKIs, mTOR inhibitors, PRRT and chemotherapy.

15.
Front Neurosci ; 13: 693, 2019.
Article En | MEDLINE | ID: mdl-31333408

Aggregation of α-synuclein (αSyn) plays a central role in the pathogenesis of Parkinson's disease (PD) and dementia with Lewy bodies (DLB). Lewy bodies (LBs) and Lewy neurites, which consist mainly of aggregated αSyn, are widely observed in the affected regions of patient brains. Except for some familial forms of PD/DLB, most sporadic PD/DLB patients express the wild-type (WT) αSyn protein without any mutations, and the mechanisms as to how WT αSyn gains the propensity to pathologically aggregate still remains unclear. Furthermore, the mechanisms by which the same αSyn protein can cause different synucleinopathies with distinct phenotypes and pathologies, such as PD, DLB, and multiple system atrophy (MSA), still remain largely unknown. Recently, mutations in the GBA1 gene (encoding glucocerebrosidase), which are responsible for the lysosomal storage disorder Gaucher disease (GD), have been reported to be the strongest risk factor for developing sporadic PD/DLB. We previously demonstrated that glucosylceramide accumulated by GBA1 deficiency promotes the conversion of αSyn into a proteinase K-resistant conformation. Furthermore, decreased glucocerebrosidase activity has also been reported in the brains of patients with sporadic PD/DLB. Moreover, αSyn pathology has also been shown in the brains of lysosomal storage disorder patients, which show glycosphingolipid accumulation. These observations suggest the possibility that altered lipid metabolism and lipid accumulation play roles in αSyn aggregation and PD/DLB pathogenesis. Indeed, several previous studies have demonstrated that lipid interactions affect the conformation of αSyn and induces its oligomerization and aggregation. In this review, we will give an overview of the association between αSyn aggregation and lipid interactions from the viewpoints of the etiology, pathology, and genetics of PD/DLB. We also discuss the distinct species of αSyn aggregates and their association with specific types of synucleinopathies, and introduce our hypothesis that lipid interactions play a role as trans-acting effectors in producing distinct strains of αSyn fibrils.

16.
Brain ; 142(9): 2845-2859, 2019 09 01.
Article En | MEDLINE | ID: mdl-31312839

Mutations in lysosomal genes increase the risk of neurodegenerative diseases, as is the case for Parkinson's disease. Here, we found that pathogenic and protective mutations in arylsulfatase A (ARSA), a gene responsible for metachromatic leukodystrophy, a lysosomal storage disorder, are linked to Parkinson's disease. Plasma ARSA protein levels were changed in Parkinson's disease patients. ARSA deficiency caused increases in α-synuclein aggregation and secretion, and increases in α-synuclein propagation in cells and nematodes. Despite being a lysosomal protein, ARSA directly interacts with α-synuclein in the cytosol. The interaction was more extensive with protective ARSA variant and less with pathogenic ARSA variant than wild-type. ARSA inhibited the in vitro fibrillation of α-synuclein in a dose-dependent manner. Ectopic expression of ARSA reversed the α-synuclein phenotypes in both cell and fly models of synucleinopathy, the effects correlating with the extent of the physical interaction between these molecules. Collectively, these results suggest that ARSA is a genetic modifier of Parkinson's disease pathogenesis, acting as a molecular chaperone for α-synuclein.


Cerebroside-Sulfatase/physiology , Molecular Chaperones/metabolism , Mutation, Missense , Parkinson Disease/metabolism , Point Mutation , alpha-Synuclein/metabolism , Adult , Aged , Animals , Animals, Genetically Modified , Brain/enzymology , Caenorhabditis elegans/genetics , Caenorhabditis elegans/metabolism , Caenorhabditis elegans Proteins/genetics , Caenorhabditis elegans Proteins/metabolism , Cells, Cultured , Cerebroside-Sulfatase/blood , Cerebroside-Sulfatase/genetics , Dementia/blood , Dementia/etiology , Drosophila Proteins/deficiency , Drosophila Proteins/genetics , Drosophila Proteins/metabolism , Drosophila melanogaster/genetics , Drosophila melanogaster/metabolism , Female , Gene Knockout Techniques , Genes, Dominant , Humans , Male , Middle Aged , Parkinson Disease/genetics , Parkinson Disease/psychology , Pedigree , Protein Aggregation, Pathological/genetics , Protein Interaction Mapping , Recombinant Proteins/metabolism
17.
PLoS One ; 14(6): e0218261, 2019.
Article En | MEDLINE | ID: mdl-31242217

Parkinson's disease (PD) is one of the most common neurodegenerative diseases, which is characterized by progressive motor dysfunction as well as non-motor symptoms. Pathological and genetic studies have demonstrated that α-synuclein (αSyn) plays key roles in the pathogenesis of PD. Although several missense mutations in the αSyn gene have been identified as causes of familial PD, the mechanisms underlying the variance in the clinical phenotypes of familial PD caused by different mutations remain elusive. Here, we established novel Drosophila models expressing either wild-type (WT) αSyn or one of five αSyn mutants (A30P, E46K, H50Q, G51D, and A53T) using site-specific transgenesis, which express transgenes at equivalent levels. Expression of either WT or mutant αSyn in the compound eyes by the GMR-GAL4 driver caused mild rough eye phenotypes with no obvious difference among the mutants. Upon pan-neuronal expression by the nSyb-GAL4 driver, these αSyn-expressing flies showed a progressive decline in locomotor function. Notably, we found that E46K, H50Q, G51D, and A53T αSyn-expressing flies showed earlier onset of locomotor dysfunction than WT αSyn-expressing flies, suggesting their enhanced toxic effects. Whereas mRNA levels of WT and mutant αSyn were almost equivalent, we found that protein expression levels of E46K αSyn were higher than those of WT αSyn. In vivo chase experiments using the drug-inducible GMR-GeneSwitch driver demonstrated that degradation of E46K αSyn protein was significantly slower than WT αSyn protein, indicating that the E46K αSyn mutant gains resistance to degradation in vivo. We therefore conclude that our novel site-specific transgenic fly models expressing either WT or mutant αSyn are useful to explore the mechanisms by which different αSyn mutants gain toxic functions in vivo.


Mutation, Missense , Parkinson Disease/metabolism , alpha-Synuclein/metabolism , Animals , Animals, Genetically Modified , Disease Models, Animal , Drosophila , Humans , Parkinson Disease/pathology , Proteolysis , alpha-Synuclein/genetics
18.
J Clin Endocrinol Metab ; 104(11): 4967-4980, 2019 11 01.
Article En | MEDLINE | ID: mdl-31074783

CONTEXT: In the human adrenal, serotonin (5-HT), released by mast cells stimulates corticosteroid secretion through activation of type 4 serotonin receptors (5-HT4R). In primary pigmented nodular adrenocortical disease cells, activation of the cAMP/protein kinase A (PKA) pathway by PRKAR1A mutations triggers upregulation of the 5-HT synthesizing enzyme tryptophan hydroxylase (TPH) and the 5-HT4, 5-HT6, and 5-HT7 receptors. Because ACTH stimulates cortisol secretion through activation of PKA, adrenocortical tissues exposed to sustained stimulation by ACTH may harbor increased expression of TPH and 5-HT4/6/7 receptors. OBJECTIVE: To investigate the effects of long-term ACTH stimulation on the serotonergic pathway in adrenals of patients with high plasma or intra-adrenal ACTH levels. METHODS: Adrenal tissues were obtained from patients with Cushing disease, ectopic secretion of ACTH [paraneoplastic Cushing syndrome; (paraCS)], 21-hydroxylase deficiency (21-OHD), primary bilateral macronodular adrenal hyperplasia with intra-adrenal ACTH presence, or cortisol-producing adenomas. TPH and 5-HT4/6/7 receptor expression was investigated using RT-PCR and immunochemistry in comparison with normal adrenals. Primary cultured adrenocortical cells originating from a patient with paraCS were incubated with 5-HT and 5-HTR agonists/antagonists. RESULTS: TPH and/or 5-HT4/6/7 receptors were overexpressed in the different types of tissues. In paraCS cultured cells, the cortisol response to 5-HT was exaggerated compared with normal adrenal cells and the stimulatory action of 5-HT was reduced by 5-HT4R antagonist. CONCLUSION: Our results indicate that prolonged activation of the cAMP/PKA pathway by ACTH induces an aberrant serotonergic stimulatory loop in the adrenal cortex that likely participates in the pathogenesis of corticosteroid hypersecretion.


Adrenal Glands/metabolism , Adrenocorticotropic Hormone/metabolism , Serotonin/metabolism , Signal Transduction , Adenoma/metabolism , Adrenal Gland Neoplasms/metabolism , Adrenocorticotropic Hormone/blood , Adult , Cushing Syndrome/metabolism , Cyclic AMP/metabolism , Female , Humans , Male , Middle Aged , Pituitary ACTH Hypersecretion/metabolism , Primary Cell Culture , Protein Kinases/metabolism , Receptors, Serotonin/metabolism , Steroid 21-Hydroxylase , Tryptophan Hydroxylase/metabolism , Up-Regulation
19.
Endocr J ; 66(4): 359-368, 2019 Apr 25.
Article En | MEDLINE | ID: mdl-30880294

The Japan Endocrine Society (JES) has the largest ratio of female membership among societies associated with Internal Medicine in Japan; half of female members are in their 20s or 30s at present. In 2009, JES organized the "JES-We-Can" committee to promote women's career development. To evaluate the effectiveness of JES-We-Can, we investigated the gender balance of various activities at JES in fiscal 2009 and 2017. Significant gender-differences were not observed in the acquisition rate of board-certified endocrinologists (BCEs) aged <40 y in 2009 and 2017. However, the acquisition rate of BCEs among women aged ≥40 y was significantly lower than men in 2009. In 2017, the gender-difference among BCEs in this group (currently aged ≥50 y) has considerably improved, but is not resolved. The acquisition rate of certificated endocrine educators (CEEs) among women was still significantly lower than men at all ages in 2017. Since the ratio of women oral speakers or poster presenters at annual academic meetings have grown to equal or surpass the membership ratio, female members make efficient contributions to JES. The numbers of women chairpersons, symposiasts, lecturers and invited speakers have increased, but remain limited. JES-We-Can was found to be effective in reducing the gender gap in academic activities at JES, but JES-We-Can should support women more intensely to raise the rate of CEEs among all ages and BCEs currently over 50 y, and to promote more women into higher positions in JES in the future. These actions are expected to introduce new and diverse perspectives into academia.


Endocrinologists , Sexism , Societies, Scientific , Female , Humans , Japan , Male , Sex Factors
20.
Hypertension ; 73(4): 885-892, 2019 04.
Article En | MEDLINE | ID: mdl-30739536

Somatic mutations have been identified in aldosterone-producing adenomas (APAs) in genes that include KCNJ5, ATP1A1, ATP2B3, and CACNA1D. Based on independent studies, there appears to be racial differences in the prevalence of somatic KCNJ5 mutations, particularly between East Asians and Europeans. Despite the high cardiovascular disease mortality of blacks, there have been no studies focusing on somatic mutations in APAs in this population. In the present study, we investigated genetic characteristics of APAs in blacks using a CYP11B2 (aldosterone synthase) immunohistochemistry-guided next-generation sequencing approach. The adrenal glands with adrenocortical adenomas from 79 black patients with primary aldosteronism were studied. Seventy-three tumors from 69 adrenal glands were confirmed to be APAs by CYP11B2 immunohistochemistry. Sixty-five of 73 APAs (89%) had somatic mutations in aldosterone-driver genes. Somatic CACNA1D mutations were the most prevalent genetic alteration (42%), followed by KCNJ5 (34%), ATP1A1 (8%), and ATP2B3 mutations (4%). CACNA1D mutations were more often observed in APAs from males than those from females (55% versus 29%, P=0.033), whereas KCNJ5 mutations were more prevalent in APAs from females compared with those from males (57% versus 13%, P<0.001). No somatic mutations in aldosterone-driver genes were identified in tumors without CYP11B2 expression. In conclusion, 89% of APAs in blacks harbor aldosterone-driving mutations, and unlike Europeans and East Asians, the most frequently mutated aldosterone-driver gene was CACNA1D. Determination of racial differences in the prevalence of aldosterone-driver gene mutations may facilitate the development of personalized medicines for patients with primary aldosteronism.


Adrenal Cortex Neoplasms/genetics , Adrenocortical Adenoma/genetics , Aldosterone/genetics , Black or African American , Genetic Predisposition to Disease , Mutation , Adrenal Cortex Neoplasms/ethnology , Adrenal Cortex Neoplasms/metabolism , Adrenal Glands/pathology , Adrenocortical Adenoma/ethnology , Adrenocortical Adenoma/metabolism , Aldosterone/metabolism , DNA Mutational Analysis , DNA, Neoplasm/genetics , Humans , Incidence , United States/epidemiology
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