Mutations in PCYT2 disrupt etherlipid biosynthesis and cause a complex hereditary spastic paraplegia

Abstract CTP:phosphoethanolamine cytidylyltransferase (ET), encoded by PCYT2, is the rate-limiting enzyme for phosphatidylethanolamine synthesis via the CDP-ethanolamine pathway. Phosphatidylethanolamine is one of the most abundant membrane lipids and is particularly enriched in the brain. We identified five individuals with biallelic PCYT2 variants clinically characterized by global developmental delay with regression, spastic para- or tetraparesis, epilepsy and progressive cerebral and cerebellar atrophy. Using patient fibroblasts we demonstrated that these variants are hypomorphic, result in altered but residual ET protein levels and concomitant reduced enzyme activity without affecting mRNA levels. The significantly better survival of hypomorphic CRISPR-Cas9 generated pcyt2 zebrafish knockout compared to a complete knockout, in conjunction with previously described data on the Pcyt2 mouse model, indicates that complete loss of ET function may be incompatible with life in vertebrates. Lipidomic analysis revealed profound lipid abnormalities in patient fibroblasts impacting both neutral etherlipid and etherphospholipid metabolism. Plasma lipidomics studies also identified changes in etherlipids that have the potential to be used as biomarkers for ET deficiency. In conclusion, our data establish PCYT2 as a disease gene for a new complex hereditary spastic paraplegia and confirm that etherlipid homeostasis is important for the development and function of the brain.

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Restoration of Noradrenergic Function in Parkinson’s Disease Model Mice

ASN NEURO ◽

10.1177/17590914211009730 ◽

2021 ◽

Vol 13 ◽

pp. 175909142110097

Author(s):

Kui Cui ◽

Fan Yang ◽

Turan Tufan ◽

Muhammad U. Raza ◽

Yanqiang Zhan ◽

...

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Transcription Factors ◽

Disease Model ◽

Neuronal Loss ◽

Mrna Levels ◽

Gene Therapies ◽

Protein Levels ◽

Dopaminergic Systems ◽

And Function

Dysfunction of the central noradrenergic and dopaminergic systems is the primary neurobiological characteristic of Parkinson’s disease (PD). Importantly, neuronal loss in the locus coeruleus (LC) that occurs in early stages of PD may accelerate progressive loss of dopaminergic neurons. Therefore, restoring the activity and function of the deficient noradrenergic system may be an important therapeutic strategy for early PD. In the present study, the lentiviral constructions of transcription factors Phox2a/2b, Hand2 and Gata3, either alone or in combination, were microinjected into the LC region of the PD model VMAT2 Lo mice at 12 and 18 month age. Biochemical analysis showed that microinjection of lentiviral expression cassettes into the LC significantly increased mRNA levels of Phox2a, and Phox2b, which were accompanied by parallel increases of mRNA and proteins of dopamine β-hydroxylase (DBH) and tyrosine hydroxylase (TH) in the LC. Furthermore, there was considerable enhancement of DBH protein levels in the frontal cortex and hippocampus, as well as enhanced TH protein levels in the striatum and substantia nigra. Moreover, these manipulations profoundly increased norepinephrine and dopamine concentrations in the striatum, which was followed by a remarkable improvement of the spatial memory and locomotor behavior. These results reveal that over-expression of these transcription factors in the LC improves noradrenergic and dopaminergic activities and functions in this rodent model of PD. It provides the necessary groundwork for the development of gene therapies of PD, and expands our understanding of the link between the LC-norepinephrine and dopamine systems during the progression of PD.

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DBC1 (Deleted in Breast Cancer 1) modulates the stability and function of the nuclear receptor Rev-erbα

Biochemical Journal ◽

10.1042/bj20121085 ◽

2013 ◽

Vol 451 (3) ◽

pp. 453-461 ◽

Cited By ~ 26

Author(s):

Claudia C. S. Chini ◽

Carlos Escande ◽

Veronica Nin ◽

Eduardo N. Chini

Keyword(s):

Breast Cancer ◽

Nuclear Receptor ◽

Clock Genes ◽

Mrna Levels ◽

Protein Levels ◽

The Stability ◽

And Function ◽

Interfering Rna ◽

In Cells

The nuclear receptor Rev-erbα has been implicated as a major regulator of the circadian clock and integrates circadian rhythm and metabolism. Rev-erbα controls circadian oscillations of several clock genes and Rev-erbα protein degradation is important for maintenance of the circadian oscillations and also for adipocyte differentiation. Elucidating the mechanisms that regulate Rev-erbα stability is essential for our understanding of these processes. In the present paper, we report that the protein DBC1 (Deleted in Breast Cancer 1) is a novel regulator of Rev-erbα. Rev-erbα and DBC1 interact in cells and in vivo, and DBC1 modulates the Rev-erbα repressor function. Depletion of DBC1 by siRNA (small interfering RNA) in cells or in DBC1-KO (knockout) mice produced a marked decrease in Rev-erbα protein levels, but not in mRNA levels. In contrast, DBC1 overexpression significantly enhanced Rev-erbα protein stability by preventing its ubiquitination and degradation. The regulation of Rev-erbα protein levels and function by DBC1 depends on both the N-terminal and C-terminal domains of DBC1. More importantly, in cells depleted of DBC1, there was a dramatic decrease in circadian oscillations of both Rev-erbα and BMAL1. In summary, our data identify DBC1 as an important regulator of the circadian receptor Rev-erbα and proposes that Rev-erbα could be involved in mediating some of the physiological effects of DBC1.

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Abstract TP274: Orosomucoid-1 Protein Increases Following Ischemic Stroke in the Brain and Periphery

Stroke ◽

10.1161/str.47.suppl_1.tp274 ◽

2016 ◽

Vol 47 (suppl_1) ◽

Author(s):

Hetal Mistry ◽

Madeline Levy ◽

Meaghan Roy-O'Reilly ◽

Louise McCullough

Keyword(s):

Sex Differences ◽

Ischemic Stroke ◽

Rna Sequencing ◽

Multiple Testing ◽

Enzyme Linked Immunosorbent Assay ◽

Mrna Levels ◽

Stroke Patients ◽

Post Stroke ◽

Protein Levels ◽

The Brain

Background and Purpose: Orosomucoid-1 (ORM-1) is an abundant protein with important roles in inflammation and immunosuppression. We utilized RNA sequencing to measure mRNA levels in human ischemic stroke patients, with confirmation by serum ORM-1 protein measurements. A mouse model of ischemic stroke was then used to examine post-stroke changes in ORM-1 within the brain itself. Hypothesis: We tested the hypothesis that ORM-1 levels increase following ischemic stroke, with sex differences in protein dynamics over time. Methods: RNA sequencing was performed on whole blood from ischemic stroke patients (n=23) and controls (n=12), with Benjamini-Hochberg correction for multiple testing. Enzyme-linked immunosorbent assay was performed on serum from ischemic stroke patients (n=28) and controls (n=8), with analysis by T-test. For brain analysis, mice (n=14) were subjected to a 90-minute middle cerebral artery occlusion (MCAO) surgery and sacrificed 6 or 24 hours after stroke. Control mice underwent parallel “sham” surgery without occlusion. Western blotting was used to detect ORM-1 protein levels in whole brain, with analysis by two-way ANOVA. Results: RNA sequencing showed a 2.8-fold increase in human ORM-1 at 24 hours post-stroke (q=.0029), an increase also seen in serum ORM-1 protein levels (p=.011). Western blot analysis of mouse brain revealed that glycosylated (p=0.0003) and naive (p=0.0333) forms of ORM-1 were higher in female mice compared to males 6 hours post-stroke. Interestingly, ORM-1 levels were higher in the brains of stroke mice at 6 hours (p=.0483), while at 24 hours ORM-1 levels in stroke mice were lower than their sham counterparts (p=.0212). In both human and mouse data, no sex differences were seen in ORM-1 levels in the brain or periphery at 24 hours post-stroke. Conclusion: In conclusion, ORM-1 is a sexually dimorphic protein involved in the early (<24 hour) response to ischemic stroke. This research serves as an initial step in determining the mechanism of ORM-1 in the ischemic stroke response and its potential as a future therapeutic target for both sexes.

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Modeling of axonal endoplasmic reticulum network by spastic paraplegia proteins

eLife ◽

10.7554/elife.23882 ◽

2017 ◽

Vol 6 ◽

Cited By ~ 25

Author(s):

Belgin Yalçın ◽

Lu Zhao ◽

Martin Stofanko ◽

Niamh C O'Sullivan ◽

Zi Han Kang ◽

...

Keyword(s):

Endoplasmic Reticulum ◽

Hereditary Spastic Paraplegia ◽

Membrane Curvature ◽

Degenerative Disease ◽

Ultrastructural Analysis ◽

Motor Axons ◽

Spastic Paraplegia ◽

Partial Loss ◽

And Function ◽

Tubular Endoplasmic Reticulum

Axons contain a smooth tubular endoplasmic reticulum (ER) network that is thought to be continuous with ER throughout the neuron; the mechanisms that form this axonal network are unknown. Mutations affecting reticulon or REEP proteins, with intramembrane hairpin domains that model ER membranes, cause an axon degenerative disease, hereditary spastic paraplegia (HSP). We show that Drosophila axons have a dynamic axonal ER network, which these proteins help to model. Loss of HSP hairpin proteins causes ER sheet expansion, partial loss of ER from distal motor axons, and occasional discontinuities in axonal ER. Ultrastructural analysis reveals an extensive ER network in axons, which shows larger and fewer tubules in larvae that lack reticulon and REEP proteins, consistent with loss of membrane curvature. Therefore HSP hairpin-containing proteins are required for shaping and continuity of axonal ER, thus suggesting roles for ER modeling in axon maintenance and function.

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A novel SPAST gene mutation identified in a Chinese family with hereditary spastic paraplegia

10.21203/rs.3.rs-26296/v1 ◽

2020 ◽

Author(s):

Weiwei Yu ◽

Haiqiang Jin ◽

Jianwen Deng ◽

Ding Nan ◽

Yining Huang

Keyword(s):

Exome Sequencing ◽

Whole Exome Sequencing ◽

Hereditary Spastic Paraplegia ◽

Dna Isolation ◽

Tertiary Structure ◽

Novel Mutation ◽

Chinese Family ◽

Spastic Paraplegia ◽

Whole Exome ◽

And Function

Abstract Background: Hereditary spastic paraplegia is a heterogeneous group of clinically and genetically neurodegenerative diseases characterized by progressive gait disorder. Hereditary spastic paraplegia can be inherited in various ways, and all modes of inheritance are associated with multiple genes or loci. At present, more than 76 disease-causing loci have been identified in hereditary spastic paraplegia patients. Here, we report a novel mutation in SPAST gene associated with hereditary spastic paraplegia in a Chinese family, further enriching the hereditary spastic paraplegia spectrum. Methods: Whole genomic DNA was extracted from peripheral blood of the 15 subjects from a Chinese family using DNA Isolation Kit. The Whole Exome Sequencing of the proband was analyzed and the result was identified in the rest individuals. RaptorX prediction tool and Protein Variation Effect Analyzer were used to predict the effects of the mutation on protein tertiary structure and function.Results: Spastic paraplegia has been inherited across at least four generations in this family, during which only four HSP patients were alive. The results obtained by analyzing the Whole Exome Sequencing of the proband exhibited a novel disease-associated in-frame deletion in the SPAST gene, and the this mutation also existed in the rest three HSP patients in this family. This in-frame deletion consists of three nucleotides deletion (c.1710_1712delGAA) within the exon 16, resulting in lysine deficiency at the position 570 of the protein (p.K570del). This novel mutation was also predicted to result in the synthesis of misfolded SPAST protein and have the deleterious effect on the function of SPAST protein.Conclusion: In this case, we reported a novel mutation in the known SPAST gene that segregated with HSP disease, which can be inherited in each generation. Simultaneously, this novel discovery significantly enriches the mutation spectrum, which provides an opportunity for further investigation of genetic pathogenesis of HSP.

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Hereditary spastic paraplegia: a clinical and epidemiological study of a Brazilian pediatric population

Arquivos de Neuro-Psiquiatria ◽

10.1590/0004-282x20180153 ◽

2019 ◽

Vol 77 (1) ◽

pp. 10-18 ◽

Cited By ~ 2

Author(s):

Roberta Paiva Magalhães Ortega ◽

Sérgio Rosemberg

Keyword(s):

Hereditary Spastic Paraplegia ◽

Age Of Onset ◽

Pediatric Population ◽

Axonal Neuropathy ◽

Laboratory Data ◽

Cerebellar Atrophy ◽

White Matter Lesions ◽

Spastic Paraplegia ◽

Brazilian Sample ◽

The Mean

ABSTRACT Aims: To investigate hereditary spastic paraplegia (HSP) in a pediatric Brazilian sample. Methods: Epidemiological, clinical, radiological and laboratory data were analyzed in 35 patients. Results: Simple HSP (HSP-S) was detected in 12 patients, and complicated HSP (HSP-C) was detected in 23 patients. The mean age of onset of symptoms was 2.9 years in HSP-S and 1.6 years in HSP-C (p = 0.023). The disease was more severe in HSP-C. There were no differences in sex, ethnic background, or family history between groups. Intellectual disability was the most frequent finding associated with HSP-C. Peripheral axonal neuropathy was found in three patients. In the HSP-C group, MRI was abnormal in 13 patients. The MRI abnormalities included nonspecific white matter lesions, cerebellar atrophy, thinning of the corpus callosum and the “ear of the lynx sign”. Conclusions: In children with spastic paraplegia, HSP must be considered whenever similar pathologies, mainly diplegic cerebral palsy, are ruled out.

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Alcohol Metabolism in the Progression of Human Nonalcoholic Steatohepatitis

Toxicological Sciences ◽

10.1093/toxsci/kfy106 ◽

2018 ◽

Vol 164 (2) ◽

pp. 428-438 ◽

Cited By ~ 13

Author(s):

Hui Li ◽

Erica Toth ◽

Nathan J Cherrington

Keyword(s):

Nonalcoholic Steatohepatitis ◽

Protein Level ◽

Mrna Levels ◽

Alcohol Metabolism ◽

Aldh Activity ◽

Nonalcoholic Fatty Liver ◽

Protein Levels ◽

Protein Adduct ◽

And Function ◽

Adh Activity

Abstract Alcohol metabolism is a well-characterized biological process that is dominated by the alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) families. Nonalcoholic steatohepatitis (NASH) is the advanced inflammatory stage of nonalcoholic fatty liver disease (NAFLD) and is known to alter the metabolism and disposition of numerous drugs. The purpose of this study was to investigate the alterations in alcohol metabolism processes in response to human NASH progression. Expression and function of ADHs, ALDHs, and catalase were examined in normal, steatosis, NASH (fatty) and NASH (not fatty) human liver samples. ALDH4A1 mRNA was significantly decreased in both NASH groups, while no significant changes were observed in the mRNA levels of other alcohol-related enzymes. The protein levels of ADH1A, ADH1B, and ADH4 were each decreased in the NASH groups, which was consistent with a decreased overall ADH activity. The protein level of ALDH2 was significantly increased in both NASH groups, while ALDH1A1 and ALDH1B1 were only decreased in NASH (fatty) samples. ALDH activity represented by oxidation of acetaldehyde was decreased in the NASH (fatty) group. The protein level of catalase was decreased in both NASH groups, though activity was unchanged. Furthermore, the significant accumulation of 4-hydroxynonenal protein adduct in NASH indicated significant oxidative stress and a potential reduction in ALDH activity. Collectively, ADH and ALDH expression and function are profoundly altered in the progression of NASH, which may have a notable impact on ADH- and ALDH-associated cellular metabolism processes and lead to significant alterations in drug metabolism mediated by these enzymes.

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Alteration of Fatty-Acid-Metabolizing Enzymes Affects Mitochondrial Form and Function in Hereditary Spastic Paraplegia

The American Journal of Human Genetics ◽

10.1016/j.ajhg.2012.11.001 ◽

2012 ◽

Vol 91 (6) ◽

pp. 1051-1064 ◽

Cited By ~ 120

Author(s):

Christelle Tesson ◽

Magdalena Nawara ◽

Mustafa A.M. Salih ◽

Rodrigue Rossignol ◽

Maha S. Zaki ◽

...

Keyword(s):

Fatty Acid ◽

Hereditary Spastic Paraplegia ◽

Spastic Paraplegia ◽

Metabolizing Enzymes ◽

Form And Function ◽

And Function

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Protrudin Regulates Endoplasmic Reticulum Morphology and Function Associated with the Pathogenesis of Hereditary Spastic Paraplegia

Journal of Biological Chemistry ◽

10.1074/jbc.m113.528687 ◽

2014 ◽

Vol 289 (19) ◽

pp. 12946-12961 ◽

Cited By ~ 35

Author(s):

Yutaka Hashimoto ◽

Michiko Shirane ◽

Fumiko Matsuzaki ◽

Shotaro Saita ◽

Takafumi Ohnishi ◽

...

Keyword(s):

Endoplasmic Reticulum ◽

Hereditary Spastic Paraplegia ◽

Spastic Paraplegia ◽

And Function

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Differential regulation of G protein expression in rat hearts exposed to chronic hypoxia

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1995.269.6.h1865 ◽

1995 ◽

Vol 269 (6) ◽

pp. H1865-H1873 ◽

Cited By ~ 15

Author(s):

R. Kacimi ◽

J. M. Moalic ◽

A. Aldashev ◽

D. E. Vatner ◽

J. P. Richalet ◽

...

Keyword(s):

Gene Expression ◽

G Protein ◽

Functional Activity ◽

Protein Level ◽

Chronic Hypoxia ◽

Mrna Level ◽

Mrna Levels ◽

Protein Levels ◽

Rat Hearts ◽

And Function

Chronic hypoxia impairs adrenergic responsiveness. A modulation of Gs and/or G1 protein alpha-subunits may be associated with the downregulation of the beta-adrenergic receptors previously found in chronic hypoxia. G protein gene expression and protein level and function in rat hearts exposed to a 30-day hypobaric chronic hypoxia were compared with control rat hearts. No change was observed in G alpha s mRNA levels in either right or left ventricles. In right ventricles, mRNA levels of G alpha i-2 increased by 40% (P < 0.05), but not in left ventricles. In both left and right ventricles, chronic hypoxia did not modify G alpha i-2 and G alpha s protein amounts, but significantly decreased functional activity of G alpha s. In conclusion, gene expression, protein levels of G alpha s and G alpha i-2, and activity of G alpha s do not change in parallel fashion with chronic hypoxia. In chronic hypoxic right ventricles, although the mRNA level of G alpha i-2 is increased, the protein level is unchanged. One potential mechanism of desensitization to catecholamines in chronic hypoxia appears to involve a decreased functional activity of G alpha s in spite of normal mRNA and protein levels

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