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Biology Direct Sep 2023Peroxisomes play a central role in tuning metabolic and signaling programs in a tissue- and cell-type-specific manner. However, the mechanisms by which the status of...
Peroxisomes play a central role in tuning metabolic and signaling programs in a tissue- and cell-type-specific manner. However, the mechanisms by which the status of peroxisomes is communicated and integrated into cellular signaling pathways are not yet understood. Herein, we report the cellular responses to peroxisomal proteotoxic stress upon silencing the peroxisomal protease/chaperone LONP2. Depletion of LONP2 triggered the accumulation of its substrate TYSND1 protease, while the overall expression of peroxisomal proteins, as well as TYSND1-dependent ACOX1 processing appeared normal, reflecting early stages of peroxisomal proteotoxic stress. Consequently, the alteration of peroxisome size and numbers, and luminal protein import failure was coupled with induction of cell-specific cellular stress responses. Specific to COS-7 cells was a strong activation of the integrated stress response (ISR) and upregulation of ribosomal biogenesis gene expression levels. Common changes between COS-7 and U2OS cell lines included repression of the retinoic acid signaling pathway and upregulation of sphingolipids. Cholesterol accumulated in the endomembrane compartments in both cell lines, consistent with evidence that peroxisomes are required for cholesterol flux out of late endosomes. These unexpected consequences of peroxisomal stress provide an important insight into our understanding of the tissue-specific responses seen in peroxisomal disorders.
Topics: Signal Transduction; Endosomes; Ribosomes; Peptide Hydrolases; Up-Regulation
PubMed: 37736739
DOI: 10.1186/s13062-023-00416-3 -
Endocrine, Metabolic & Immune Disorders... Sep 2023Paediatric palliative care (PPC) has a significant role in improving the quality of life of children with life-limiting or life-threatening illnesses, diminishing...
INTRODUCTION
Paediatric palliative care (PPC) has a significant role in improving the quality of life of children with life-limiting or life-threatening illnesses, diminishing symptom burden, and providing holistic support to patients and families. Inherited metabolic diseases (IMD) are a group of heterogeneous diseases that often present with severe neurologic impairment, needing lifelong care and challenging symptom management.
OBJECTIVE
Our aim was to characterize the cohort of patients with IMD followed by the paediatric palliative care team (PPCT) and to describe the provision of care provided.
METHODS
The descriptive analysis of demographic, clinical, and care delivery data of a cohort of paediatric patients was carried out with a confirmed diagnosis of IMD, followed in a Reference Centre, in the care of PPCT between 2018 and 2023.
RESULTS
Thirteen (10%) of a total of 134 patients in the care of PPCT had a confirmed diagnosis of an IMD: 6 mitochondrial, 3 peroxisomal, 3 lysosomal, and 1 pterin metabolism disorder. The median age at referral was 9 years (0-18), the median duration of care was 2 years [2-4], median number of home visits in the last year was 2 [1-4], and median number of outpatient consults was 4 [2 -8]. Twelve patients (92%) had no autonomy in their activities of daily living. Neurologic (100%), gastrointestinal (92%), and respiratory (69%) symptoms were the main focus of care. All patients were polymedicated (5 or more different drugs). Nine (69%) had percutaneous gastrostomy and 2 (15%) had noninvasive ventilation. Median hospital admissions before and after starting care by PPCT were 4 and 1. Moreover, three patients died and one was at home.
CONCLUSION
Mitochondrial, lysosomal, and peroxisomal disorders are complex multisystemic diseases that very often have no treatment intended to cure. These patients have a heavy symptom burden and frequent intercurrences. Addressing these symptoms is challenging, but PPC has proven to reduce hospital admissions with consequent improvement in quality of life. In the future, PPC should be available for all children and families with life-threatening conditions.
PubMed: 37711121
DOI: 10.2174/1871530323666230914114425 -
Brain : a Journal of Neurology Apr 2024The acyl-CoA-binding domain-containing protein 6 (ACBD6) is ubiquitously expressed, plays a role in the acylation of lipids and proteins and regulates the...
The acyl-CoA-binding domain-containing protein 6 (ACBD6) is ubiquitously expressed, plays a role in the acylation of lipids and proteins and regulates the N-myristoylation of proteins via N-myristoyltransferase enzymes (NMTs). However, its precise function in cells is still unclear, as is the consequence of ACBD6 defects on human pathophysiology. Using exome sequencing and extensive international data sharing efforts, we identified 45 affected individuals from 28 unrelated families (consanguinity 93%) with bi-allelic pathogenic, predominantly loss-of-function (18/20) variants in ACBD6. We generated zebrafish and Xenopus tropicalis acbd6 knockouts by CRISPR/Cas9 and characterized the role of ACBD6 on protein N-myristoylation with myristic acid alkyne (YnMyr) chemical proteomics in the model organisms and human cells, with the latter also being subjected further to ACBD6 peroxisomal localization studies. The affected individuals (23 males and 22 females), aged 1-50 years, typically present with a complex and progressive disease involving moderate-to-severe global developmental delay/intellectual disability (100%) with significant expressive language impairment (98%), movement disorders (97%), facial dysmorphism (95%) and mild cerebellar ataxia (85%) associated with gait impairment (94%), limb spasticity/hypertonia (76%), oculomotor (71%) and behavioural abnormalities (65%), overweight (59%), microcephaly (39%) and epilepsy (33%). The most conspicuous and common movement disorder was dystonia (94%), frequently leading to early-onset progressive postural deformities (97%), limb dystonia (55%) and cervical dystonia (31%). A jerky tremor in the upper limbs (63%), a mild head tremor (59%), parkinsonism/hypokinesia developing with advancing age (32%) and simple motor and vocal tics were among other frequent movement disorders. Midline brain malformations including corpus callosum abnormalities (70%), hypoplasia/agenesis of the anterior commissure (66%), short midbrain and small inferior cerebellar vermis (38% each) as well as hypertrophy of the clava (24%) were common neuroimaging findings. Acbd6-deficient zebrafish and Xenopus models effectively recapitulated many clinical phenotypes reported in patients including movement disorders, progressive neuromotor impairment, seizures, microcephaly, craniofacial dysmorphism and midbrain defects accompanied by developmental delay with increased mortality over time. Unlike ACBD5, ACBD6 did not show a peroxisomal localization and ACBD6-deficiency was not associated with altered peroxisomal parameters in patient fibroblasts. Significant differences in YnMyr-labelling were observed for 68 co- and 18 post-translationally N-myristoylated proteins in patient-derived fibroblasts. N-myristoylation was similarly affected in acbd6-deficient zebrafish and X. tropicalis models, including Fus, Marcks and Chchd-related proteins implicated in neurological diseases. The present study provides evidence that bi-allelic pathogenic variants in ACBD6 lead to a distinct neurodevelopmental syndrome accompanied by complex and progressive cognitive and movement disorders.
Topics: Animals; Female; Humans; Male; ATP-Binding Cassette Transporters; Intellectual Disability; Microcephaly; Movement Disorders; Nervous System Malformations; Neurodevelopmental Disorders; Tremor; Zebrafish; Infant; Child, Preschool; Child; Adolescent; Young Adult; Adult; Middle Aged
PubMed: 37951597
DOI: 10.1093/brain/awad380 -
Ophthalmology Dec 2023Individuals with Zellweger spectrum disorder (ZSD) manifest a spectrum of clinical phenotypes but almost all have retinal degeneration leading to blindness. The onset,... (Review)
Review
PURPOSE
Individuals with Zellweger spectrum disorder (ZSD) manifest a spectrum of clinical phenotypes but almost all have retinal degeneration leading to blindness. The onset, extent, and progression of retinal findings have not been well described. It is crucial to understand the natural history of vision loss in ZSD to define reliable endpoints for future interventional trials. Herein, we describe ophthalmic findings in the largest number of ZSD patients to date.
DESIGN
Retrospective review of longitudinal data from medical charts and review of cross-sectional data from the literature.
PARTICIPANTS
Sixty-six patients with ZSD in the retrospective cohort and 119 patients reported in the literature, divided into 4 disease phenotypes based on genotype or clinical severity.
METHODS
We reviewed ophthalmology records collected from the retrospective cohort (Clinicaltrials.gov NCT01668186) and performed a scoping review of the literature for ophthalmic findings in patients with ZSD. We extracted available ophthalmic data and analyzed by age and disease severity.
MAIN OUTCOME MEASURES
Visual acuity (VA), posterior and anterior segment descriptions, nystagmus, refraction, electroretinography findings, visual evoked potentials, and OCT results and images.
RESULTS
Visual acuity was worse at younger ages in those with severe disease compared with older patients with intermediate to mild disease for all 78 participants analyzed, with a median VA of 0.93 logarithm of the minimum angle of resolution (Snellen 20/320). Longitudinal VA data revealed slow loss over time and legal blindness onset at an average age of 7.8 years. Funduscopy showed retinal pigmentation, macular abnormalities, small or pale optic discs, and attenuated vessels with higher prevalence in milder severity groups and did not change with age. Electroretinography waveforms were diminished in 91% of patients, 46% of which were extinguished and did not change with age. OCT in milder patients revealed schitic changes in 18 of 23 individuals (age range 1.8 to 30 years), with evolution or stable macular edema.
CONCLUSIONS
In ZSD, VA slowly deteriorates and is associated with disease severity, serial electroretinography is not useful for documenting vision loss progression, and intraretinal schitic changes may be common. Multiple systematic measures are required to assess retinal dystrophy accurately in ZSD, including functional vision measures.
FINANCIAL DISCLOSURE(S)
Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.
Topics: Humans; Child; Infant; Child, Preschool; Adolescent; Young Adult; Adult; Cross-Sectional Studies; Evoked Potentials, Visual; Retrospective Studies; Zellweger Syndrome; Blindness; Retina
PubMed: 37541626
DOI: 10.1016/j.ophtha.2023.07.026 -
Human Molecular Genetics Nov 2023X-linked adrenoleukodystrophy is a severe demyelinating neurodegenerative disease mainly affecting males. The severe cerebral adrenoleukodystrophy (cALD) phenotype has a...
X-linked adrenoleukodystrophy is a severe demyelinating neurodegenerative disease mainly affecting males. The severe cerebral adrenoleukodystrophy (cALD) phenotype has a poor prognosis and underlying mechanism of onset and progression of neuropathology remains poorly understood. In this study we aim to integrate metabolomic and microRNA (miRNA) datasets to identify variances associated with cALD. Postmortem brain tissue samples from five healthy controls (CTL) and five cALD patients were utilized in this study. White matter from ALD patients was obtained from normal-appearing areas, away from lesions (NLA) and from the periphery of lesions- plaque shadow (PLS). Metabolomics was performed by gas chromatography coupled with time-of-flight mass spectrometry and miRNA expression analysis was performed by next generation sequencing (RNAseq). Principal component analysis revealed that among the three sample groups (CTL, NLA and PLS) there were 19 miRNA, including several novel miRNA, of which 17 were increased with disease severity and 2 were decreased. Untargeted metabolomics revealed 13 metabolites with disease severity-related patterns with 7 increased and 6 decreased with disease severity. Ingenuity pathway analysis of differentially altered metabolites and miRNA comparing CTL with NLA and NLA with PLS, identified several hubs of metabolite and signaling molecules and their upstream regulation by miRNA. The transomic approach to map the crosstalk between miRNA and metabolomics suggests involvement of specific molecular and metabolic pathways in cALD and offers opportunity to understand the complex underlying mechanism of disease severity in cALD.
Topics: Male; Humans; Adrenoleukodystrophy; MicroRNAs; Neurodegenerative Diseases; Brain; Phenotype; Metabolomics
PubMed: 37656183
DOI: 10.1093/hmg/ddad144 -
Analytica Chimica Acta Apr 2024Correct identification and quantification of different sterol biomarkers can be used as a first-line diagnostic approach for inherited metabolic disorders (IMD). The...
Correct identification and quantification of different sterol biomarkers can be used as a first-line diagnostic approach for inherited metabolic disorders (IMD). The main drawbacks of current methodologies are related to lack of selectivity and sensitivity for some of these compounds. To address this, we developed and validated two sensitive and selective assays for quantification of six cholesterol biosynthesis pathway intermediates (total amount (free and esterified form) of 7-dehydrocholesterol (7-DHC), 8-dehydrocholesterol (8-DHC), desmosterol, lathosterol, lanosterol and cholestanol), two phytosterols (total amount (free and esterified form) of campesterol and sitosterol) and free form of two oxysterols (7-ketocholesterol (7-KC) and 3β,5α,6β-cholestane-triol (C-triol). For quantification of four cholesterol intermediates we based our analytical approach on sterol derivatization with 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD). Quantification of all analytes is performed using UPLC coupled to an Orbitrap high resolution mass spectrometry (HRMS) system, with detection of target ions through full scan acquisition using positive atmospheric pressure chemical ionization (APCI) mode. UPLC and MS parameters were optimized to achieve high sensitivity and selectivity. Analog stable isotope labeled for each compound was used for proper quantification and correction for recovery, matrix effects and process efficiency. Precision (2.4%-12.3% inter-assay variation), lower limit of quantification (0.027 nM-50.5 nM) and linearity (5.5 μM (R 0.999) - 72.3 μM (R 0.997)) for phyto- and oxysterols were determined. The diagnostic potential of these two assays in a cohort of patients (n = 31, 50 samples) diagnosed with IMD affecting cholesterol and lysosomal/peroxisomal homeostasis is demonstrated.
Topics: Humans; Sterols; Chromatography, High Pressure Liquid; Mass Spectrometry; Phytosterols; Oxysterols
PubMed: 38401937
DOI: 10.1016/j.aca.2024.342347 -
Frontiers in Endocrinology 2023PM can cause adverse health effects via several pathways, such as inducing pulmonary and systemic inflammation, penetration into circulation, and activation of the...
PM can cause adverse health effects via several pathways, such as inducing pulmonary and systemic inflammation, penetration into circulation, and activation of the autonomic nervous system. In particular, the impact of PM exposure on the liver, which plays an important role in metabolism and detoxification to maintain internal environment homeostasis, is getting more attention in recent years. In the present study, C57BL/6J mice were randomly assigned and treated with PM suspension and PBS solution for 8 weeks. Then, hepatic tissue was prepared and identified by metabolomics analysis and transcriptomics analysis. PM exposure can cause extensive metabolic disturbances, particularly in lipid and amino acids metabolic dysregulation.128 differential expression metabolites (DEMs) and 502 differently expressed genes (DEGs) between the PM exposure group and control group were detected. The Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses showed that DEGs were significantly enriched in two disease pathways, non-alcoholic fatty liver disease (NAFLD) and type II diabetes mellitus (T2DM), and three signaling pathways, which are TGF-beta signaling, AMPK signaling, and mTOR signaling. Besides, further detection of acylcarnitine levels revealed accumulation in liver tissue, which caused restricted lipid consumption. Furthermore, lipid droplet accumulation in the liver was confirmed by Oil Red O staining, suggesting hepatic steatosis. Moreover, the aberrant expression of three key transcription factors revealed the potential regulatory effects in lipid metabolic disorders, the peroxisomal proliferative agent-activated receptors (PPARs) including PPARα and PPARγ is inhibited, and the activated sterol regulator-binding protein 1 (SREBP1) is overexpressed. Our results provide a novel molecular and genetic basis for a better understanding of the mechanisms of PM exposure-induced hepatic metabolic diseases, especially in lipid metabolism.
Topics: Mice; Animals; Diabetes Mellitus, Type 2; Mice, Inbred C57BL; Non-alcoholic Fatty Liver Disease; Lipid Metabolism Disorders; Particulate Matter; Lipids
PubMed: 37780625
DOI: 10.3389/fendo.2023.1212291 -
Science China. Life Sciences Aug 2023Peroxisomal disorders (PDs) are a heterogenous group of diseases caused by defects in peroxisome biogenesis or functions. X-linked adrenoleukodystrophy is the most...
Peroxisomal disorders (PDs) are a heterogenous group of diseases caused by defects in peroxisome biogenesis or functions. X-linked adrenoleukodystrophy is the most prevalent form of PDs and results from mutations in the ABCD1 gene, which encodes a transporter mediating the uptake of very long-chain fatty acids (VLCFAs). The curative approaches for PDs are very limited. Here, we investigated whether cholesterol accumulation in the lysosomes is a biochemical feature shared by a broad spectrum of PDs. We individually knocked down fifteen PD-associated genes in cultured cells and found ten induced cholesterol accumulation in the lysosome. 2-Hydroxypropyl-β-cyclodextrin (HPCD) effectively alleviated the cholesterol accumulation phenotype in PD-mimicking cells through reducing intracellular cholesterol content as well as promoting cholesterol redistribution to other cellular membranes. In ABCD1 knockdown cells, HPCD treatment lowered reactive oxygen species and VLCFA to normal levels. In Abcd1 knockout mice, HPCD injections reduced cholesterol and VLCFA sequestration in the brain and adrenal cortex. The plasma levels of adrenocortical hormones were increased and the behavioral abnormalities were greatly ameliorated upon HPCD administration. Together, our results suggest that defective cholesterol transport underlies most, if not all, PDs, and that HPCD can serve as a novel and effective strategy for the treatment of PDs.
Topics: Mice; Animals; ATP-Binding Cassette Transporters; 2-Hydroxypropyl-beta-cyclodextrin; Fatty Acids; Adrenoleukodystrophy; Cholesterol; Lysosomes; ATP Binding Cassette Transporter, Subfamily D, Member 1
PubMed: 36971991
DOI: 10.1007/s11427-022-2260-4 -
The Journal of Clinical Endocrinology... Oct 2023Males with adrenoleukodystrophy (ALD) have an 80% lifetime risk of developing adrenal insufficiency (AI), which can be life-threatening when undetected. Newborn...
CONTEXT
Males with adrenoleukodystrophy (ALD) have an 80% lifetime risk of developing adrenal insufficiency (AI), which can be life-threatening when undetected. Newborn screening (NBS) for ALD has been implemented in 29 states, yet the impact of NBS upon clinical management has not been reported.
OBJECTIVE
To investigate whether the implementation of NBS has altered the time to diagnosis of AI in children with ALD.
DESIGN
We conducted a retrospective medical chart review of pediatric patients with ALD.
SETTING
All patients were seen in a leukodystrophy clinic in an academic medical center.
PATIENTS
We included all pediatric patients with ALD who were seen between May 2006 and January 2022. We identified 116 patients (94% boys).
MAIN OUTCOME MEASURES
We extracted information about ALD diagnosis in all patients and AI surveillance, diagnosis, and treatment in boys with ALD.
RESULTS
Thirty-one (27%) patients were diagnosed with ALD by NBS, and 85 (73%) were diagnosed outside the newborn period. The prevalence of AI among boys in our patient population was 74%. AI diagnosis was made significantly earlier in boys diagnosed with ALD by NBS than in boys diagnosed outside the newborn period (median [IQR] age of diagnosis = 6.7 [3.9, 12.12] months vs 6.05 [3.74, 8.35] years) (P < .001). When maintenance dose of glucocorticoids were initiated, there were significant differences in ACTH and peak cortisol levels in patients diagnosed by NBS and outside the newborn period.
CONCLUSIONS
Our results suggest that implementing NBS for ALD leads to significantly earlier detection of AI and earlier initiation of glucocorticoid supplementation in boys affected by ALD.
Topics: Male; Infant, Newborn; Humans; Child; Female; Adrenoleukodystrophy; Retrospective Studies; Neonatal Screening; Adrenal Insufficiency; Early Diagnosis
PubMed: 37220095
DOI: 10.1210/clinem/dgad286 -
Molecular Therapy : the Journal of the... May 2024X-linked adrenoleukodystrophy (ALD), an inherited neurometabolic disorder caused by mutations in ABCD1, which encodes the peroxisomal ABC transporter, mainly affects the...
X-linked adrenoleukodystrophy (ALD), an inherited neurometabolic disorder caused by mutations in ABCD1, which encodes the peroxisomal ABC transporter, mainly affects the brain, spinal cord, adrenal glands, and testes. In ALD patients, very-long-chain fatty acids (VLCFAs) fail to enter the peroxisome and undergo subsequent β-oxidation, resulting in their accumulation in the body. It has not been tested whether in vivo base editing or prime editing can be harnessed to ameliorate ALD. We developed a humanized mouse model of ALD by inserting a human cDNA containing the pathogenic variant into the mouse Abcd1 locus. The humanized ALD model showed increased levels of VLCFAs. To correct the mutation, we tested both base editing and prime editing and found that base editing using ABE8e(V106W) could correct the mutation in patient-derived fibroblasts at an efficiency of 7.4%. Adeno-associated virus (AAV)-mediated systemic delivery of NG-ABE8e(V106W) enabled robust correction of the pathogenic variant in the mouse brain (correction efficiency: ∼5.5%), spinal cord (∼5.1%), and adrenal gland (∼2%), leading to a significant reduction in the plasma levels of C26:0/C22:0. This established humanized mouse model and the successful correction of the pathogenic variant using a base editor serve as a significant step toward treating human ALD disease.
PubMed: 38796705
DOI: 10.1016/j.ymthe.2024.05.027