RESUMO
Background: Despite being the second most common type of neurodegeneration with brain iron accumulation, there is limited literature on PLA2G6-associated neurodegeneration (PLAN) within the Asian ethnicity, particularly in the Indian context. Methods: We conducted a retrospective observational study on patients with pathogenic/likely pathogenic PLA2G6 variants based on exome sequencing. Results: We identified 26 patients (22 families, 15 males) of genetically-confirmed PLAN with a median age of 22.5 years and age at onset of 13.0 years, encompassing various subtypes: infantile neuroaxonal dystrophy (5/26;19.2%), atypical neuroaxonal dystrophy (3/26;11.5%), dystonia-parkinsonism (5/26;19.2%), dystonia-parkinsonism-myoclonus (n = 4, 15.38%), early-onset Parkinson's disease (2/26;7.7%), complex dystonia (2/26;7.7%), and complicated hereditary spastic paraparesis (cHSP; 5/26;19.2%). The common initial symptoms included walking difficulty (7/26;26.9%), developmental regression (6/26;23.1%), and slowness (4/26;15.4%). Dystonia (14/26;53.8%), followed by parkinsonism (11/26; 42.3%), was the most common motor symptom. Non-motor symptoms included cognitive decline (12/26;46.2%) and behavioral changes (6/26;23.1%). Neuroimaging revealed cerebellar atrophy in 23/26 (88.5%) patients and claval hypertrophy in 80% (4/5) of INAD patients. Levodopa responsiveness was noted in 12 of 14 patients with parkinsonism/dystonia who received levodopa, and dyskinesia was noted in 10/11 patients. Genetic analysis revealed a total of 19 unique variants in PLA2G6 gene, of which 11 were novel. Twelve patients harbored the c.2222G>A variant, which is predominantly seen in Asian subpopulations. Conclusions: The study introduces 26 new patients of PLAN and 12 patients associated with the c.2222G>A variant, potentially forming the most extensive single center series to date. It also expands the phenotypic, neuroimaging, and genotypic spectrum of PLAN.
Assuntos
Fosfolipases A2 do Grupo VI , Distrofias Neuroaxonais , Humanos , Fosfolipases A2 do Grupo VI/genética , Masculino , Feminino , Adolescente , Adulto Jovem , Adulto , Estudos Retrospectivos , Criança , Distrofias Neuroaxonais/genética , Distrofias Neuroaxonais/diagnóstico por imagem , Distrofias Neuroaxonais/fisiopatologia , Pré-Escolar , Doenças Neurodegenerativas/genética , Doenças Neurodegenerativas/diagnóstico por imagem , Transtornos Parkinsonianos/genética , Transtornos Parkinsonianos/diagnóstico por imagem , Imageamento por Ressonância Magnética , Índia , Pessoa de Meia-Idade , Centros de Atenção TerciáriaRESUMO
We asked whether acute redox signaling from mitochondria exists concomitantly to fatty acid- (FA-) stimulated insulin secretion (FASIS) at low glucose by pancreatic ß-cells. We show that FA ß-oxidation produces superoxide/H2O2, providing: i) mitochondria-to-plasma-membrane redox signaling, closing KATP-channels synergically with elevated ATP (substituting NADPH-oxidase-4-mediated H2O2-signaling upon glucose-stimulated insulin secretion); ii) activation of redox-sensitive phospholipase iPLA2γ/PNPLA8, cleaving mitochondrial FAs, enabling metabotropic GPR40 receptors to amplify insulin secretion (IS). At fasting glucose, palmitic acid stimulated IS in wt mice; palmitic, stearic, lauric, oleic, linoleic, and hexanoic acids also in perifused pancreatic islets (PIs), with suppressed 1st phases in iPLA2γ/PNPLA8-knockout mice/PIs. Extracellular/cytosolic H2O2-monitoring indicated knockout-independent redox signals, blocked by mitochondrial antioxidant SkQ1, etomoxir, CPT1 silencing, and catalase overexpression, all inhibiting FASIS, keeping ATP-sensitive K+-channels open, and diminishing cytosolic [Ca2+]-oscillations. FASIS in mice was a postprandially delayed physiological event. Redox signals of FA ß-oxidation are thus documented, reaching the plasma membrane, essentially co-stimulating IS.
Assuntos
Membrana Celular , Ácidos Graxos , Secreção de Insulina , Células Secretoras de Insulina , Mitocôndrias , Oxirredução , Transdução de Sinais , Animais , Camundongos , Mitocôndrias/metabolismo , Ácidos Graxos/metabolismo , Células Secretoras de Insulina/metabolismo , Membrana Celular/metabolismo , Camundongos Knockout , Insulina/metabolismo , Peróxido de Hidrogênio/metabolismo , Fosfolipases A2 do Grupo VI/metabolismo , Fosfolipases A2 do Grupo VI/genética , Glucose/metabolismo , Receptores Acoplados a Proteínas GRESUMO
Cisplatin (CDDP) is a platinum-based drug with anti-cancer activity and is widely used as a standard therapy for bladder cancer. It is well known that CDDP causes cell death by increasing the generation of reactive oxygen species (ROS) and lipid peroxidation, but the mechanism of its anti-cancer effects has not been fully elucidated. There are still some problems such as chemoresistance in CDDP therapy. In the present study, we found the expression of Ca2+-independent phospholipase A2γ (iPLA2γ), which has been reported to regulate cellular redox homeostasis by inhibiting lipid peroxide accumulation, in human bladder cancer tissues. Thus, we investigated the effect of iPLA2γ knockdown on CDDP-induced bladder cancer cell death. As a result, we found that iPLA2γ knockdown significantly enhanced CDDP-induced apoptosis, intracellular and mitochondrial ROS production, cytochrome c release and caspase activation in bladder cancer cells. Moreover, mitochondrial membrane potential was decreased and peroxidation of mitochondrial phospholipids was increased by iPLA2γ knockdown. It was also shown that co-treatment of bromoenol lactone, an iPLA2 inhibitor, increased CDDP-induced apoptosis. These results indicated that iPLA2γ plays an important role in protecting bladder cancer cells from CDDP-induced apoptosis, and that iPLA2γ inhibitors might represent a novel strategy in CDDP-based multi-drug therapy.
Assuntos
Apoptose , Cisplatino , Fosfolipases A2 do Grupo VI , Peroxidação de Lipídeos , Mitocôndrias , Fosfolipídeos , Espécies Reativas de Oxigênio , Neoplasias da Bexiga Urinária , Humanos , Neoplasias da Bexiga Urinária/genética , Neoplasias da Bexiga Urinária/patologia , Neoplasias da Bexiga Urinária/metabolismo , Neoplasias da Bexiga Urinária/tratamento farmacológico , Apoptose/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Cisplatino/farmacologia , Mitocôndrias/metabolismo , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/genética , Fosfolipases A2 do Grupo VI/metabolismo , Fosfolipases A2 do Grupo VI/genética , Peroxidação de Lipídeos/efeitos dos fármacos , Linhagem Celular Tumoral , Fosfolipídeos/metabolismo , Antineoplásicos/farmacologia , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Técnicas de Silenciamento de Genes , Pironas/farmacologia , NaftalenosRESUMO
Peroxiredoxin 6 (Prdx6) repairs peroxidized membranes by reducing oxidized phospholipids, and by replacing oxidized sn-2 fatty acyl groups through hydrolysis/reacylation by its phospholipase A2 (aiPLA2) and lysophosphatidylcholine acyltransferase activities. Prdx6 is highly expressed in the lung, and intact lungs and cells null for Prdx6 or with single-point mutations that inactivate either Prdx6-peroxidase or aiPLA2 activity alone exhibit decreased viability, increased lipid peroxidation, and incomplete repair when exposed to paraquat, hyperoxia, or organic peroxides. Ferroptosis is form of cell death driven by the accumulation of phospholipid hydroperoxides. We studied the role of Prdx6 as a ferroptosis suppressor in the lung. We first compared the expression Prdx6 and glutathione peroxidase 4 (GPx4) and visualized Prdx6 and GPx4 within the lung. Lung Prdx6 mRNA levels were five times higher than GPx4 levels. Both Prdx6 and GPx4 localized to epithelial and endothelial cells. Prdx6 knockout or knockdown sensitized lung endothelial cells to erastin-induced ferroptosis. Cells with genetic inactivation of either aiPLA2 or Prdx6-peroxidase were more sensitive to ferroptosis than WT cells, but less sensitive than KO cells. We then conducted RNA-seq analyses in Prdx6-depleted cells to further explore how the loss of Prdx6 sensitizes lung endothelial cells to ferroptosis. Prdx6 KD upregulated transcriptional signatures associated with selenoamino acid metabolism and mitochondrial function. Accordingly, Prdx6 deficiency blunted mitochondrial function and increased GPx4 abundance whereas GPx4 KD had the opposite effect on Prdx6. Moreover, we detected Prdx6 and GPx4 interactions in intact cells, suggesting that both enzymes cooperate to suppress lipid peroxidation. Notably, Prdx6-depleted cells remained sensitive to erastin-induced ferroptosis despite the compensatory increase in GPx4. These results show that Prdx6 suppresses ferroptosis in lung endothelial cells and that both aiPLA2 and Prdx6-peroxidase contribute to this effect. These results also show that Prdx6 supports mitochondrial function and modulates several coordinated cytoprotective pathways in the pulmonary endothelium.
Assuntos
Células Endoteliais , Ferroptose , Fosfolipases A2 do Grupo VI , Peroxidação de Lipídeos , Pulmão , Peroxirredoxina VI , Fosfolipídeo Hidroperóxido Glutationa Peroxidase , Piperazinas , Ferroptose/genética , Peroxirredoxina VI/metabolismo , Peroxirredoxina VI/genética , Fosfolipídeo Hidroperóxido Glutationa Peroxidase/metabolismo , Fosfolipídeo Hidroperóxido Glutationa Peroxidase/genética , Pulmão/metabolismo , Pulmão/patologia , Animais , Células Endoteliais/metabolismo , Camundongos , Humanos , Fosfolipases A2/metabolismo , Fosfolipases A2/genética , Camundongos KnockoutRESUMO
Neurodegeneration with brain iron accumulation (NBIA) encompasses a clinically and genetically heterogeneous group of rare disorders. Here, we report clinical, neuroimaging and genetic studies in twenty three Brazilian NBIA patients. In thirteen subjects, deleterious variants were detected in known NBIA-causing genes (PANK2, PLA2G6, C9ORF12, WDR45 and FA2H), including previously unreported variants in PANK2 and PLA2G6. Two patients carried rare, likely pathogenic variants in genes not previously associated with NBIA: KMT2A c.11785A > C (p.Ile3929Leu), and TIMM8A c.127T > C (p.Cys43Arg), suggesting an expansion of their associated phenotypes to include NBIA. In eight patients the etiology remains unsolved, suggesting variants undetectable by the adopted methods, or the existence of additional NBIA-causing genes.
Assuntos
Neuroimagem , Humanos , Brasil , Feminino , Masculino , Adulto , Adolescente , Adulto Jovem , Criança , Pré-Escolar , Imageamento por Ressonância Magnética , Encéfalo/diagnóstico por imagem , Encéfalo/metabolismo , Encéfalo/patologia , Distrofias Neuroaxonais/genética , Distrofias Neuroaxonais/diagnóstico por imagem , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Ferro/metabolismo , Distúrbios do Metabolismo do Ferro/genética , Distúrbios do Metabolismo do Ferro/diagnóstico por imagem , Fosfolipases A2 do Grupo VIRESUMO
Polymorphisms of group VIA calcium-independent phospholipase A2 (PLA2G6) are associated with blood C-reactive protein suggesting its role in inflammation. We showed that myeloid-specific Pla2g6-deficiency in Pla2g6M-/- mice led to exaggerated inflammation and fibrosis in a lean fatty liver model. We here investigated whether these mutants display alteration in immune response after treatment with E. coli lipopolysaccharides (LPS) under acute (a single dose) and persistent (four doses) conditions. Without LPS treatment, male Pla2g6M-/- (but not Flox) mice at 12 months of age exhibited splenomegaly and hepatic necrosis, and ~ 30 % of them exhibited autoimmune hepatitis showing lymphoplasma cells with CD3(+) and CD45R(+) staining. Under acute LPS, male mutants showed an elevation of plasma MIP-1α and immunoglobulinA as well as upregulation of hepatic apoptosis and fibrosis PARP-1, Bax, MCP-1, α-SMA, and collagen I proteins. Their bone-marrow-derived macrophages also showed an elevation of MIP-1α release upon LPS stimulation in vitro. Female mutants under acute LPS showed a moderate increase in plasma KC/CXCL1, MCP-1, and IL10, and they showed no remarkable increase in hepatic fibrosis under acute or persistent LPS. Male mutants under persistent LPS displayed an elevation of aspartate aminotransferase, blood eosinophils, and hepatic apoptosis. Moreover, ~30 % of these mutants exhibited eosinophilic sclerosing portal hepatitis associated with an upregulated protein expression of hepatic CD8α, CD68, eosinophilic cationic protein, and Ly6G. Thus, myeloid-PLA2G6 deficiency led to an autoimmune and LPS-induced inflammatory liver disease via MIP-1α in a male-predominant manner. Our results may be applicable to patients with PLA2G6 mutations who undergo bacterial infection and sepsis.
Assuntos
Lipopolissacarídeos , Fosfolipases A2 Independentes de Cálcio , Animais , Feminino , Humanos , Masculino , Camundongos , Quimiocina CCL3 , Escherichia coli , Fibrose , Fosfolipases A2 do Grupo VI , Inflamação/induzido quimicamente , Inflamação/genética , Inflamação/metabolismo , Lipopolissacarídeos/farmacologiaRESUMO
A variant of the phospholipase A2 group VI gene (PLA2G6, PARK14) has been found to cause early-onset Parkinson's disease (EOPD). In this study, we reprogrammed peripheral blood mononuclear cells from a 39-year-old patient with EOPD carrying a homozygous PLA2G6 mutation c.1898C > T (p. A633V) to generate the human induced pluripotent stem cell line LNDWCHi001-A. This cell line was identified based on pluripotent markers and displayed differentiation capacity, providing an essential model for studying the pathogenesis of EOPD and drug screening.
Assuntos
Células-Tronco Pluripotentes Induzidas , Doença de Parkinson , Transtornos Parkinsonianos , Humanos , Adulto , Doença de Parkinson/patologia , Células-Tronco Pluripotentes Induzidas/metabolismo , Leucócitos Mononucleares/metabolismo , Transtornos Parkinsonianos/genética , Mutação/genética , Fosfolipases A2 do Grupo VI/genética , Fosfolipases A2 do Grupo VI/metabolismoRESUMO
BACKGROUND: Phospholipase-associated neurodegeneration (PLAN) caused by mutations in the PLA2G6 gene is a rare neurodegenerative disorder that presents with four sub-groups. Infantile neuroaxonal dystrophy (INAD) and PLA2G6-related dystonia-parkinsonism are the main two subtypes. In this cohort, we reviewed clinical, imaging, and genetic features of 25 adult and pediatric patients harboring variants in the PLA2G6. METHODS: An extensive review of the patients' data was carried out. Infantile Neuroaxonal Dystrophy Rating Scale (INAD-RS) was used for evaluating the severity and progression of INAD patients. Whole-exome sequencing was used to determine the disease's underlying etiology followed by co-segregation analysis using Sanger sequencing. In silico prediction analysis based on the ACMG recommendation was used to assess the pathogenicity of genetic variants. We aimed to survey a genotype-genotype correlation in PLA2G6 considering all reported disease-causing variants in addition to our patients using the HGMD database and the chi-square statistical approach. RESULTS: Eighteen cases of INAD and 7 cases of late-onset PLAN were enrolled. Among 18 patients with INAD, gross motor regression was the most common presenting symptom. Considering the INAD-RS total score, the mean rate of progression was 0.58 points per month of symptoms (Standard error 0.22, lower 95% - 1.10, and upper 95% - 0.15). Sixty percent of the maximum potential loss in the INAD-RS had occurred within 60 months of symptom onset in INAD patients. Among seven adult cases of PLAN, hypokinesia, tremor, ataxic gate, and cognitive impairment were the most frequent clinical features. Various brain imaging abnormalities were also observed in 26 imaging series of these patients with cerebellar atrophy being the most common finding in more than 50%. Twenty unique variants in 25 patients with PLAN were detected including nine novel variants. Altogether, 107 distinct disease-causing variants from 87 patient were analyzed to establish a genotype-phenotype correlation. The P value of the chi-square test did not indicate a significant relationship between age of disease onset and the distribution of reported variants on PLA2G6. CONCLUSION: PLAN presents with a wide spectrum of clinical symptoms from infancy to adulthood. PLAN should be considered in adult patients with parkinsonism or cognition decline. Based on the current knowledge, it is not possible to foresee the age of disease onset based on the identified genotype.
Assuntos
Distrofias Neuroaxonais , Transtornos Parkinsonianos , Adulto , Criança , Humanos , Genótipo , Fosfolipases A2 do Grupo VI/genética , Mutação/genética , Distrofias Neuroaxonais/genética , Transtornos Parkinsonianos/genética , FenótipoRESUMO
Here we investigated whether antipsychotic treatment was influenced by three polymorphisms: rs10798059 (BanI) in the phospholipase A2 (PLA2)G4A gene, rs4375 in PLA2G6, and rs1549637 in PLA2G4C. A total of 186 antipsychotic-naïve first-episode psychosis patients or nonadherent chronic psychosis individuals (99 males and 87 females) were genotyped by polymerase chain reaction analysis/restriction fragment length polymorphism. At baseline, and after 8 weeks of treatment with various antipsychotic medications, we assessed patients' Positive and Negative Syndrome Scale (PANSS) scores, PANSS factors, and metabolic syndrome-related parameters (fasting plasma lipid and glucose levels, and body mass index). We found that PLA2G4A polymorphism influenced changes in PANSS psychopathology, and PLA2G6 polymorphism influenced changes in PANSS psychopathology and metabolic parameters. PLA2G4C polymorphism did not show any impact on PANSS psychopathology or metabolic parameters. The polymorphisms' effect sizes were estimated as moderate to strong, with contributions ranging from around 6.2-15.7%. Furthermore, the polymorphisms' effects manifested in a gender-specific manner.
Assuntos
Antipsicóticos , Fosfolipases A2 do Grupo VI , Transtornos Psicóticos , Feminino , Humanos , Masculino , Antipsicóticos/uso terapêutico , Genótipo , Polimorfismo Genético , Transtornos Psicóticos/tratamento farmacológico , Transtornos Psicóticos/genética , Fosfolipases A2 do Grupo VI/genéticaRESUMO
BACKGROUND: PLA2G6-associated neurodegeneration (PLAN) can be categorized into infantile neuroaxonal dystrophy (INAD), atypical neuroaxonal dystrophy (aNAD), neurodegeneration with brain iron accumulation (NBIA), and early-onset parkinsonism (EOP). OBJECTIVES: To determine the genotype-phenotype association in PLAN. METHODS: "PLA2G6" or "PARK14" or "phospholipase A2 group VI" or "iPLA2ß" were searched across MEDLINE from June 23, 1997, to March 1, 2023. A total of 391 patients were identified, and 340 patients of them were finally included in the assessment. RESULTS: The loss of function (LOF) mutation ratios were significantly different (p < 0.001), highest in INAD, followed by NBIA, aNAD, and EOP. Four ensemble scores (i.e., BayesDel, VARITY, ClinPred, and MetaRNN) were assessed to predict the deleteriousness of missense mutations and demonstrated significant differences (p < 0.001). Binary logistic regression analyses demonstrated that LOF mutations were independently associated with brain iron accumulation (p = 0.006) and ataxia (p = 0.025). CONCLUSIONS: LOF or more deleterious missense mutations are more likely to promote the development of serious phenotype of PLAN, and LOF mutations are independently associated with brain iron accumulation and ataxia.
Assuntos
Distrofias Neuroaxonais , Transtornos Parkinsonianos , Humanos , Mutação/genética , Transtornos Parkinsonianos/genética , Estudos de Associação Genética , Distrofias Neuroaxonais/genética , Ferro , Ataxia , Fosfolipases A2 do Grupo VI/genéticaRESUMO
PLA2G6-associated neurodegeneration (PLAN) represents a continuum of clinically and genetically heterogeneous neurodegenerative disorders with overlapping features. Usually, it encompasses three autosomal recessive diseases, including infantile neuroaxonal dystrophy or neurodegeneration with brain iron accumulation (NBIA) 2A, atypical neuronal dystrophy with childhood-onset or NBIA2B, and adult-onset dystonia-parkinsonism form named PARK14, and possibly a certain subtype of hereditary spastic paraplegia. PLAN is caused by variants in the phospholipase A2 group VI gene (PLA2G6), which encodes an enzyme involved in membrane homeostasis, signal transduction, mitochondrial dysfunction, and α-synuclein aggregation. In this review, we discuss PLA2G6 gene structure and protein, functional findings, genetic deficiency models, various PLAN disease phenotypes, and study strategies in the future. Our primary aim is to provide an overview of genotype-phenotype correlations of PLAN subtypes and speculate on the role of PLA2G6 in potential mechanisms underlying these conditions.
Assuntos
Distrofias Neuroaxonais , Doenças Neurodegenerativas , Transtornos Parkinsonianos , Humanos , Doenças Neurodegenerativas/genética , Transtornos Parkinsonianos/genética , Distrofias Neuroaxonais/genética , Estudos de Associação Genética , Mutação , Fosfolipases A2 do Grupo VI/genéticaRESUMO
INTRODUCTION: The phospholipase A2 group VI gene (PLA2G6) encodes an enzyme that catalyzes the hydrolytic release of fatty acids from phospholipids. Four neurological disorders with infantile, juvenile, or early adult-onset are associated with PLA2G6 genetic alterations, namely infantile neuroaxonal dystrophy (INAD), atypical neuroaxonal dystrophy (ANAD), dystonia-parkinsonism (DP), and autosomal recessive early-onset parkinsonism (AREP). Few studies in Africa reported PLA2G6-associated disorders and none with parkinsonism of late adult onset. MATERIAL AND METHODS: The patients were clinically assessed following UK Brain Bank diagnostic criteria and International Parkinson and Movement Disorder Society's Unified Parkinson's Disease Rating Scale (MDS-UPDRS). Brain MRI without contrast was performed. Genetic testing was done using a custom-made Twist panel, screening 34 known genes, 27 risk factors, and 8 candidate genes associated with parkinsonism. Filtered variants were PCR-amplified and validated using Sanger sequencing and also tested in additional family members to study their segregation. RESULT: Two siblings born to consanguineous parents developed parkinsonism at the age of 58 and 60 years, respectively. MRI showed an enlarged right hippocampus in patient 2, but no overt abnormalities indicative of INAD or iron deposits. We found two heterozygous variants in PLA2G6, an in-frame deletion NM_003560:c.2070_2072del (p.Val691del) and a missense variant NM_003560:c.956C>T (p.Thr319Met). Both variants were classified as pathogenic. CONCLUSION: This is the first case in which PLA2G6 is associated with late-onset parkinsonism. Functional analysis is needed to confirm the dual effect of both variants on the structure and function of iPLA2ß.
Assuntos
Distonia , Distúrbios Distônicos , Transtornos Parkinsonianos , Adulto , Humanos , Pessoa de Meia-Idade , Distonia/genética , Distúrbios Distônicos/genética , Testes Genéticos , Fosfolipases A2 do Grupo VI/genética , Mutação , Transtornos Parkinsonianos/genéticaRESUMO
Infantile neuroaxonal dystrophy (INAD) is a rare neurodegenerative disease caused mainly by homozygous or compound heterozygous mutations in the PLA2G6 gene. We generated a human induced pluripotent stem cell (hiPSC) line (ONHi001-A) using fibroblasts derived from a patient with INAD. The patient exhibited c.517C > T (p.Q173X) and c.1634A > G (p.K545R) compound heterozygous mutations in the PLA2G6 gene. This hiPSC line may be useful for studying the pathogenic mechanism underlying INAD.
Assuntos
Células-Tronco Pluripotentes Induzidas , Distrofias Neuroaxonais , Doenças Neurodegenerativas , Humanos , Células-Tronco Pluripotentes Induzidas/patologia , Doenças Neurodegenerativas/genética , Mutação/genética , Homozigoto , Distrofias Neuroaxonais/genética , Distrofias Neuroaxonais/patologia , Fosfolipases A2 do Grupo VI/genéticaAssuntos
Lissencefalias Clássicas e Heterotopias Subcorticais em Banda , Distrofias Neuroaxonais , Humanos , Ferro , Imageamento por Ressonância Magnética/métodos , Distrofias Neuroaxonais/diagnóstico por imagem , Distrofias Neuroaxonais/genética , Encéfalo/diagnóstico por imagem , Fosfolipases A2 do Grupo VI/genéticaRESUMO
Infantile neuroaxonal dystrophy (INAD) is caused by recessive variants in PLA2G6 and is a lethal pediatric neurodegenerative disorder. Loss of the Drosophila homolog of PLA2G6, leads to ceramide accumulation, lysosome expansion, and mitochondrial defects. Here, we report that retromer function, ceramide metabolism, the endolysosomal pathway, and mitochondrial morphology are affected in INAD patient-derived neurons. We show that in INAD mouse models, the same features are affected in Purkinje cells, arguing that the neuropathological mechanisms are evolutionary conserved and that these features can be used as biomarkers. We tested 20 drugs that target these pathways and found that Ambroxol, Desipramine, Azoramide, and Genistein alleviate neurodegenerative phenotypes in INAD flies and INAD patient-derived neural progenitor cells. We also develop an AAV-based gene therapy approach that delays neurodegeneration and prolongs lifespan in an INAD mouse model.
Assuntos
Proteínas de Drosophila , Distrofias Neuroaxonais , Transtornos Parkinsonianos , Camundongos , Animais , Neurônios/metabolismo , Transtornos Parkinsonianos/metabolismo , Drosophila/metabolismo , Ceramidas/metabolismo , Distrofias Neuroaxonais/genética , Distrofias Neuroaxonais/metabolismo , Distrofias Neuroaxonais/patologia , Fosfolipases A2 do Grupo VI/metabolismo , Proteínas do Olho/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismoRESUMO
Phospholipase A2 group 6 (PLA2G6, iPLA2ß or PARK14) gene encodes a calcium-independent group 6 phospholipase A2 enzyme and is associated with young-onset autosomal recessive Parkinson's disease (PD). We generated human induced pluripotent stem cell (iPSC) lines from a patient with young-onset PD carrying a homozygous PLA2G6: c.2222G>A (p. Arg741Gln) mutation (NCBSi003-A) and unaffected heterozygous parent (NCBSi004-A). These iPSC lines will be used for investigating the key molecular signatures of young-onset PD (YOPD), and to understand the predictive phenotypes of the disease.
Assuntos
Células-Tronco Pluripotentes Induzidas , Doença de Parkinson , Transtornos Parkinsonianos , Humanos , Doença de Parkinson/genética , Células-Tronco Pluripotentes Induzidas/metabolismo , Transtornos Parkinsonianos/genética , Mutação , Transgenes , Fosfolipases A2 do Grupo VI/genéticaAssuntos
Estimulação Encefálica Profunda , Fosfolipases A2 do Grupo VI , Atividade Motora , Transtornos Parkinsonianos , Núcleo Subtalâmico , Humanos , China , Estimulação Encefálica Profunda/métodos , Fosfolipases A2 do Grupo VI/genética , Mutação/genética , Transtornos Parkinsonianos/fisiopatologia , Transtornos Parkinsonianos/terapia , Núcleo Subtalâmico/fisiopatologiaRESUMO
Polymorphisms of phospholipase A2VIA (iPLA2ß or PLA2G6) are associated with body weights and blood C-reactive protein. The role of iPLA2ß/PLA2G6 in non-alcoholic steatohepatitis (NASH) is still elusive because female iPla2ß-null mice showed attenuated hepatic steatosis but exacerbated hepatic fibrosis after feeding with methionine- and choline-deficient diet (MCDD). Herein, female mice with myeloid- (MPla2g6-/-) and hepatocyte- (LPla2g6-/-) specific PLA2G6 deletion were generated and phenotyped after MCDD feeding. Without any effects on hepatic steatosis, MCDD-fed MPla2g6-/- mice showed further exaggeration of liver inflammation and fibrosis as well as elevation of plasma TNFα, CCL2, and circulating monocytes. Bone-marrow-derived macrophages (BMDMs) from MPla2g6-/- mice displayed upregulation of PPARγ and CEBPα proteins, and elevated release of IL6 and CXCL1 under LPS stimulation. LPS-stimulated BMDMs from MCDD-fed MPla2g6-/- mice showed suppressed expression of M1 Tnfa and Il6, but marked upregulation of M2 Arg1, Chil3, IL10, and IL13 as well as chemokine receptors Ccr2 and Ccr5. This in vitro shift was associated with exaggeration of hepatic M1/M2 cytokines, chemokines/chemokine receptors, and fibrosis genes. Contrarily, MCDD-fed LPla2g6-/- mice showed a complete protection which was associated with upregulation of Ppara/PPARα and attenuated expression of Pparg/PPARγ, fatty-acid uptake, triglyceride synthesis, and de novo lipogenesis genes. Interestingly, LPla2g6-/- mice fed with chow or MCDD displayed an attenuation of blood monocytes and elevation of anti-inflammatory lipoxin A4 in plasma and liver. Thus, PLA2G6 inactivation specifically in myeloid cells and hepatocytes led to opposing phenotypes in female mice undergoing NASH. Hepatocyte-specific PLA2G6 inhibitors may be further developed for treatment of this disease.
Assuntos
Hepatopatia Gordurosa não Alcoólica , Feminino , Camundongos , Animais , Hepatopatia Gordurosa não Alcoólica/genética , Fosfolipases A2 Independentes de Cálcio , PPAR gama/genética , Interleucina-6 , Lipopolissacarídeos , Dieta , Hepatócitos , Fenótipo , Metionina , Colina , Racemetionina , PPAR alfa , Receptores de Quimiocinas , Fosfolipases A2 do Grupo VI/genéticaAssuntos
Distúrbios Distônicos , Transtornos Parkinsonianos , Adulto , Humanos , Transtornos Parkinsonianos/diagnóstico por imagem , Transtornos Parkinsonianos/genética , Distúrbios Distônicos/diagnóstico por imagem , Distúrbios Distônicos/genética , Mutação/genética , Fosfolipases A2 do Grupo VI/genéticaRESUMO
Orai2 is a component of store-operated Calcium channels (SOCCs) and exerts a pivotal role in immunity. In intestinal macrophages (Mφs), Orai2 deficiency influenced linoleic acid (LA)-arachidonic acid (ARA) derivatives by regulating Pla2g6 and Alox5. 16S rRNA sequencing showed that deleting Orai2 facilitated the prevalence of Akkermansia muciniphila, and untargeted metabolomics confirmed the suppressed level of leukotriene A. Moreover, Orai2 deficiency ameliorated the progression of experimental murine colitis, as shown by attenuated structural collapse of colon and pro-inflammatory cytokine concentrations, and rescued dysbiosis. The administration of a Pla2g6 inhibitor (Bromoenol lactone) not only inhibited the relative abundance of A. muciniphila in the feces of Orai2 knockout (Orai2-/-) mice, but also abolished the increased activity of Calcium-released activated Calcium channel (CRAC) in Orai2-/- intestinal Mφs, corroborating the involvement of Pla2g6 in Orai2 signaling. In conclusion, Orai2 deficiency increases Pla2g6 and hence facilitating A. muciniphila colonization, which might be a potential strategy to combat colitis.