Accumulation Of Very Long Chain Fatty Acids Research Articles

Dynamic relationships among pathways producing hydrocarbons and fatty acids of maize silk cuticular waxes.

The hydrophobic cuticle is the first line of defense between aerial portions of plants and the external environment. On maize (Zea mays L.) silks, the cuticular cutin matrix is infused with cuticular waxes, consisting of a homologous series of very long-chain fatty acids (VLCFAs), aldehydes, and hydrocarbons. Together with VLC fatty-acyl-CoAs (VLCFA-CoAs), these metabolites serve as precursors, intermediates and end-products of the cuticular wax biosynthetic pathway. To deconvolute the potentially confounding impacts of the change in silk microenvironment and silk development on this pathway, we profiled cuticular waxes on the silks of the inbreds B73 and Mo17, and their reciprocal hybrids. Multivariate interrogation of these metabolite abundance data demonstrates that VLCFA-CoAs and total free VLCFAs are positively correlated with the cuticular wax metabolome, and this metabolome is primarily affected by changes in the silk microenvironment and plant genotype. Moreover, the genotype effect on the pathway explains the increased accumulation of cuticular hydrocarbons with a concomitant reduction in cuticular VLCFA accumulation on B73 silks, suggesting that the conversion of VLCFA-CoAs to hydrocarbons is more effective in B73 than Mo17. Statistical modeling of the ratios between cuticular hydrocarbons and cuticular VLCFAs reveals a significant role of precursor chain length in determining this ratio. This study establishes the complexity of the product-precursor relationships within the silk cuticular wax-producing network by dissecting both the impact of genotype and the allocation of VLCFA-CoA precursors to different biological processes, and demonstrates that longer chain VLCFA-CoAs are preferentially utilized for hydrocarbon biosynthesis.

Integrated transcriptome and fatty acid profiling provide the insights into lipid metabolism during seed development of Acer truncatum

Owing to its numerous physiological effects, Acer truncatum seed oil (ATO) is increasingly popular as a novel source of edible oil in China. To explore the characteristics of ATO accumulation, the potential biosynthetic mechanisms of the main fatty acids (FAs) were investigated during the six different developmental stages of A. truncatum seeds (i.e., S1 - S6). The results indicated that the ATO yields significantly increased from S1 to S5, and then decreased (S6), whereby the ratio of unsaturated fatty acids reached up to 82.63–90.65% of the total ATO content. The highest content of nervonic acid was observed at S6. Dynamic transcriptome data analyses revealed that 38,932 genes were actively transcribed in the five seed developmental stages (i.e., S1-S5), 103 of which were related to lipid metabolism. Combining with the gene expression and FA profiling, the potential metabolism of the main FA was further explored. Notably, changes in C18:1-CoA transformation were observed at the later periods of A. truncatum seed development (especially from S4 to S5), which might be the key factor limiting the accumulation of very long-chain fatty acids (VLCFAs). Additionally, 24 key functional genes related to lipid metabolism were highly correlated with VLCFA biosynthesis. Finally, 11 potential transcription factors from the bHLH, GRAS, bZIP, AP2/ERF, and MADS families exhibited highly positive correlations with these key functional genes in lipid metabolism, all of which might play important roles in regulating of VLCFA accumulation.

MSC-Derived Small Extracellular Vesicles Exert Cardioprotective Effect Through Reducing VLCFAs and Apoptosis in Human Cardiac Organoid IRI Model.

Cardiovascular diseases (CVDs) are the leading cause of death worldwide, accounting for 31% of all deaths globally. Myocardial ischemia-reperfusion injury (IRI), a common complication of CVDs, is a major cause of mortality and morbidity. Studies have shown efficacious use of mesenchymal stem cells-derived small extracellular vesicles (MSCs-EVs) to mitigate IRI in animals, but few research has been done on human-related models. In this study, human embryonic stem cell-derived chambered cardiac organoid (CCO) was used as a model system to study the effects of MSC-EVs on myocardial IRI. The results revealed that MSC-EVs treatment reduced apoptosis and improved contraction resumption of the CCOs. Metabolomics analysis showed that this effect could be attributed to EVs' ability to prevent the accumulation of unsaturated very long-chain fatty acids (VLCFAs). This was corroborated when inhibition of fatty acid synthase, which was reported to reduce VLCFAs, produced a similar protective effect to EVs. Overall, this study uncovered the mechanistic role of MSC-EVs in mitigating IRI that involves preventing the accumulation of unsaturated VLCFA, decreasing cell death, and improving contraction resumption in CCOs.

Protective effect of oleic acid against very long-chain fatty acid-induced apoptosis in peroxisome-deficient CHO cells

Very long-chain fatty acids (VLCFAs) are degraded exclusively in peroxisomes, as evidenced by the accumulation of VLCFAs in patients with certain peroxisomal disorders. Although accumulation of VLCFAs is considered to be associated with health issues, including neuronal degeneration, the mechanisms underlying VLCFAs-induced tissue degeneration remain unclear. Here, we report the toxic effect of VLCFA and protective effect of C18: 1 FA in peroxisome-deficient CHO cells. We examined the cytotoxicity of saturated and monounsaturated VLCFAs with chain-length at C20–C26, and found that longer and saturated VLCFA showed potent cytotoxicity at lower accumulation levels. Furthermore, the extent of VLCFA-induced toxicity was found to be associated with a decrease in cellular C18:1 FA levels. Notably, supplementation with C18:1 FA effectively rescued the cells from VLCFA-induced apoptosis without reducing the cellular VLCFAs levels, implying that peroxisome-deficient cells can survive in the presence of accumulated VLCFA, as long as the cells keep sufficient levels of cellular C18:1 FA. These results suggest a therapeutic potential of C18:1 FA in peroxisome disease and may provide new insights into the pharmacological effect of Lorenzo's oil, a 4:1 mixture of C18:1 and C22:1 FA.

Immune response of BV-2 microglial cells is impacted by peroxisomal beta-oxidation.

Microglia are crucial for brain homeostasis, and dysfunction of these cells is a key driver in most neurodegenerative diseases, including peroxisomal leukodystrophies. In X-linked adrenoleukodystrophy (X-ALD), a neuroinflammatory disorder, very long-chain fatty acid (VLCFA) accumulation due to impaired degradation within peroxisomes results in microglial defects, but the underlying mechanisms remain unclear. Using CRISPR/Cas9 gene editing of key genes in peroxisomal VLCFA breakdown (Abcd1, Abcd2, and Acox1), we recently established easily accessible microglial BV-2 cell models to study the impact of dysfunctional peroxisomal β-oxidation and revealed a disease-associated microglial-like signature in these cell lines. Transcriptomic analysis suggested consequences on the immune response. To clarify how impaired lipid degradation impacts the immune function of microglia, we here used RNA-sequencing and functional assays related to the immune response to compare wild-type and mutant BV-2 cell lines under basal conditions and upon pro-inflammatory lipopolysaccharide (LPS) activation. A majority of genes encoding proinflammatory cytokines, as well as genes involved in phagocytosis, antigen presentation, and co-stimulation of T lymphocytes, were found differentially overexpressed. The transcriptomic alterations were reflected by altered phagocytic capacity, inflammasome activation, increased release of inflammatory cytokines, including TNF, and upregulated response of T lymphocytes primed by mutant BV-2 cells presenting peptides. Together, the present study shows that peroxisomal β-oxidation defects resulting in lipid alterations, including VLCFA accumulation, directly reprogram the main cellular functions of microglia. The elucidation of this link between lipid metabolism and the immune response of microglia will help to better understand the pathogenesis of peroxisomal leukodystrophies.

Ataxia with giant axonopathy in Acbd5-deficient mice halted by adeno-associated virus gene therapy.

Acyl-CoA binding domain containing 5 (ACBD5) is a critical player in handling very long chain fatty acids (VLCFA) en route for peroxisomal β-oxidation. Mutations in ACBD5 lead to the accumulation of VLCFA and patients present retinal dystrophy, ataxia, psychomotor delay and a severe leukodystrophy. Using CRISPR/Cas9, we generated and characterized an Acbd5 Gly357* mutant allele. Gly357* mutant mice recapitulated key features of the human disorder, including reduced survival, impaired locomotion and reflexes, loss of photoreceptors, and demyelination. The ataxic presentation of Gly357* mice involved the loss of cerebellar Purkinje cells and a giant axonopathy throughout the CNS. Lipidomic studies provided evidence for the extensive lipid dysregulation caused by VLCFA accumulation. Following a proteomic survey, functional studies in neurons treated with VLCFA unravelled a deregulated cytoskeleton with reduced actin dynamics and increased neuronal filopodia. We also show that an adeno-associated virus-mediated gene delivery ameliorated the gait phenotypes and the giant axonopathy, also improving myelination and astrocyte reactivity. Collectively, we established a mouse model with significance for VLCFA-related disorders. The development of relevant neuropathological outcomes enabled the understanding of mechanisms modulated by VLCFA and the evaluation of the efficacy of preclinical therapeutic interventions.

X-linked adrenoleukodystrophy and primary adrenal insufficiency.

X-linked adrenoleukodystrophy (X-ALD; OMIM:300100) is a progressive neurodegenerative disorder caused by a congenital defect in the ATP-binding cassette transporters sub-family D member 1 gene (ABCD1) producing adrenoleukodystrophy protein (ALDP). According to population studies, X-ALD has an estimated birth prevalence of 1 in 17.000 subjects (considering both hemizygous males and heterozygous females), and there is no evidence that this prevalence varies among regions or ethnic groups. ALDP deficiency results in a defective peroxisomal β-oxidation of very long chain fatty acids (VLCFA). As a consequence of this metabolic abnormality, VLCFAs accumulate in nervous system (brain white matter and spinal cord), testis and adrenal cortex. All X-ALD affected patients carry a mutation on the ABCD1 gene. Nevertheless, patients with a defect on the ABCD1 gene can have a dramatic difference in the clinical presentation of the disease. In fact, X-ALD can vary from the most severe cerebral paediatric form (CerALD), to adult adrenomyeloneuropathy (AMN), Addison-only and asymptomatic forms. Primary adrenal insufficiency (PAI) is one of the main features of X-ALD, with a prevalence of 70% in ALD/AMN patients and 5% in female carriers. The pathogenesis of X-ALD related PAI is still unclear, even if a few published data suggests a defective adrenal response to ACTH, related to VLCFA accumulation with progressive disruption of adrenal cell membrane function and ACTH receptor activity. The reason why PAI develops only in a proportion of ALD/AMN patients remains incompletely understood. A growing consensus supports VLCFA assessment in all male children presenting with PAI, as early diagnosis and start of therapy may be essential for X-ALD patients. Children and adults with PAI require individualized glucocorticoid replacement therapy, while mineralocorticoid therapy is needed only in a few cases after consideration of hormonal and electrolytes status. Novel approaches, such as prolonged release glucocorticoids, offer potential benefit in optimizing hormonal replacement for X-ALD-related PAI. Although the association between PAI and X-ALD has been observed in clinical practice, the underlying mechanisms remain poorly understood. This paper aims to explore the multifaceted relationship between PAI and X-ALD, shedding light on shared pathophysiology, clinical manifestations, and potential therapeutic interventions.

Differential roles for ACBD4 and ACBD5 in peroxisome–ER interactions and lipid metabolism

Peroxisomes and the endoplasmic reticulum (ER) are intimately linked subcellular organelles, physically connected at membrane contact sites. While collaborating in lipid metabolism, for example, of very long-chain fatty acids (VLCFAs) and plasmalogens, the ER also plays a role in peroxisome biogenesis. Recent work identified tethering complexes on the ER and peroxisome membranes that connect the organelles. These include membrane contacts formed via interactions between the ER protein VAPB (vesicle-associated membrane protein-associated protein B) and the peroxisomal proteins ACBD4 and ACBD5 (acyl-coenzyme A-binding domain protein). Loss of ACBD5 has been shown to cause a significant reduction in peroxisome-ER contacts and accumulation of VLCFAs. However, the role of ACBD4 and the relative contribution these two proteins make to contact site formation and recruitment of VLCFAs to peroxisomes remain unclear. Here, we address these questions using a combination of molecular cell biology, biochemical, and lipidomics analyses following loss of ACBD4 or ACBD5 in HEK293cells. We show that the tethering function of ACBD5 is not absolutely required for efficient peroxisomal β-oxidation of VLCFAs. We demonstrate that loss of ACBD4 does not reduce peroxisome-ER connections or result in the accumulation of VLCFAs. Instead, the loss of ACBD4 resulted in an increase in the rate of β-oxidation of VLCFAs. Finally, we observe an interaction between ACBD5 and ACBD4, independent of VAPB binding. Overall, our findings suggest that ACBD5 may act as a primary tether and VLCFA recruitment factor, whereas ACBD4 may have regulatory functions in peroxisomal lipid metabolism at the peroxisome-ER interface.

Abcd1 deficiency accelerates cuprizone-induced oligodendrocyte loss and axonopathy in a demyelinating mouse model of X-linked adrenoleukodystrophy

X-linked adrenoleukodystrophy (X-ALD), the most frequent, inherited peroxisomal disease, is caused by mutations in the ABCD1 gene encoding a peroxisomal lipid transporter importing very long-chain fatty acids (VLCFAs) from the cytosol into peroxisomes for degradation via β-oxidation. ABCD1 deficiency results in accumulation of VLCFAs in tissues and body fluids of X-ALD patients with a wide range of phenotypic manifestations. The most severe variant, cerebral X-ALD (CALD) is characterized by progressive inflammation, loss of the myelin-producing oligodendrocytes and demyelination of the cerebral white matter. Whether the oligodendrocyte loss and demyelination in CALD are caused by a primary cell autonomous defect or injury to oligodendrocytes or by a secondary effect of the inflammatory reaction remains unresolved. To address the role of X-ALD oligodendrocytes in demyelinating pathophysiology, we combined the Abcd1 deficient X-ALD mouse model, in which VLCFAs accumulate without spontaneous demyelination, with the cuprizone model of toxic demyelination. In mice, the copper chelator cuprizone induces reproducible demyelination in the corpus callosum, followed by remyelination upon cuprizone removal. By immunohistochemical analyses of oligodendrocytes, myelin, axonal damage and microglia activation during de-and remyelination, we found that the mature oligodendrocytes of Abcd1 KO mice are more susceptible to cuprizone-induced cell death compared to WT mice in the early demyelinating phase. Furthermore, this effect was mirrored by a greater extent of acute axonal damage during demyelination in the KO mice. Abcd1 deficiency did not affect the function of microglia in either phase of the treatment. Also, the proliferation and differentiation of oligodendrocyte precursor cells and remyelination progressed at similar rates in both genotypes. Taken together, our findings point to an effect of Abcd1 deficiency on mature oligodendrocytes and the oligodendrocyte-axon unit, leading to increased vulnerability in the context of a demyelinating insult.

Severe Pressure Ulcers in Two Patients With Adrenoleukodystrophy

Adrenoleukodystrophy (ALD) is a rare X-linked disease that affects the metabolism of very long-chain fatty acids (VLCFAs), leading to cognitive deterioration, progressive spastic paraplegia, sensory disturbance, adrenocortical insufficiency, and bladder and bowel abnormalities. Although the symptoms of ALD correspond to the risk of developing pressure ulcers, a pressure ulcer has never been listed as a complication of ALD. We present two cases of ALD with severe pressure ulcers in the pelvic region and feet. The first case was a 27-year-old male patient with adolescent cerebral-type ALD who had pressure ulcers with bone exposure on the sacral and bilateral greater trochanter region. The second case was a 64-year-old male patient with adrenomyeloneuropathy (AMN) phenotype who had pressure ulcers on the sacral region and both feet. Both patients had VLCFA accumulation and a likely pathogenic variant in the ABCD1 gene, the causative gene of ALD. These cases indicate that ALD patients with immobility and incontinence have a higher risk of developing severe pressure ulcers, which requires the proactive identification of ALD patients and early multidisciplinary intervention for patients and their families to prevent the development of pressure ulcers.

Nutritional status of children affected by X-linked adrenoleukodystrophy.

Adrenoleukodystrophy (ALD) is a rare X-linked metabolic disorder that causes the accumulation of very-long-chain fatty acids (VLCFAs) (C26:0) and the subsequent variety of clinical and neurological symptoms. Little is known about nutritional status and dietary habits of children affected by ALD, and so the present study aimed to assess nutritional status and food intake in children with ALD, also exploring the relationship between food intake and the consumption of disease-specific dietary supplements to reduce blood C26:0 concentrations and increase monounsaturated fatty acids (C26:1). All patients underwent a clinical and neurological evaluation and a comprehensive nutritional assessment. The association of VLCFA concentrations with dietary lipids was assessed. Nine boys (11.49 ± 3.61 years) were enrolled in a cross-sectional study. All patients were normal weight, with normal resting energy expenditure. Only six of nine patients followed the low-fat diet and dietary supplements. An inverse association was found between the food intake of polyunsaturated lipids and C26:0; conversely, the C26:0 was positively associated with the dietary saturated lipids. When consumed, dietary supplement consumption correlated positively with C26:1 (ρ = 0.917, p = 0.029) and no correlation was found with C26:0 (ρ = 0.410, p = 0,493). No children were found to be malnourished or overweight or obese; however, half of the children reported excessive body fat, probably as a result of the pharmacotherapies. A low-fat diet could be adjuvant in the management of the accumulation of VLCFAs, but poor dietary compliance to disease-specific nutritional guidelines appears to be a major problem of this condition and underlines the need for a structured and personalised nutritional management in ALD disease.

Two Single Nucleotide Deletions in the ABCD1 Gene Causing Distinct Phenotypes of X-Linked Adrenoleukodystrophy

X-linked adrenoleukodystrophy (X-ALD) is a rare inborn error of the peroxisomal metabolism caused by pathologic variants in the ATP-binding cassette transporter type D, member 1 (ABCD1) gene located on the X-chromosome. ABCD1 protein, also known as adrenoleukodystrophy protein, is responsible for transport of the very long chain fatty acids (VLCFA) from cytoplasm into the peroxisomes. Therefore, altered function or lack of the ABCD1 protein leads to accumulation of VLCFA in various tissues and blood plasma leading to either rapidly progressive leukodystrophy (cerebral ALD), progressive adrenomyeloneuropathy (AMN), or isolated primary adrenal insufficiency (Addison's disease). We report two distinct single nucleotide deletions in the ABCD1 gene, c.253delC [p.Arg85Glyfs*18] in exon 1, leading to both cerebral ALD and to AMN phenotype in one family, and c.1275delA [p.Phe426Leufs*15] in exon 4, leading to AMN and primary adrenal insufficiency in a second family. For the latter variant, we demonstrate reduced mRNA expression and a complete absence of the ABCD1 protein in PBMC. Distinct mRNA and protein expression in the index patient and heterozygous carriers does not associate with VLCFA concentration in plasma, which is in line with the absence of genotype-phenotype correlation in X-ALD.

Peroxisomes attenuate cytotoxicity of very long-chain fatty acids

One of the major functions of peroxisomes in mammals is oxidation of very long-chain fatty acids (VLCFAs). Genetic defects in peroxisomal β-oxidation result in the accumulation of VLCFAs and lead to a variety of health problems, such as demyelination of nervous tissues. However, the mechanisms by which VLCFAs cause tissue degeneration have not been fully elucidated. Recently, we found that the addition of small amounts of isopropanol can enhance the solubility of saturated VLCFAs in an aqueous medium. In this study, we characterized the biological effect of extracellular VLCFAs in peroxisome-deficient Chinese hamster ovary (CHO) cells, neural crest-derived pheochromocytoma cells (PC12), and immortalized adult Fischer rat Schwann cells (IFRS1) using this solubilizing technique. C20:0 FA was the most toxic of the C16–C26 FAs tested in all cells. The basis of the toxicity of C20:0 FA was apoptosis and was observed at 5 μM and 30 μM in peroxisome-deficient and wild-type CHO cells, respectively. The sensitivity of wild-type CHO cells to cytotoxic C20:0 FA was enhanced in the presence of a peroxisomal β-oxidation inhibitor. Further, a positive correlation was evident between cell toxicity and the extent of intracellular accumulation of toxic FA. These results suggest that peroxisomes are pivotal in the detoxification of apoptotic VLCFAs by preventing their accumulation.

Antioxidant Response in Human X-Linked Adrenoleukodystrophy Fibroblasts.

Redox imbalance, mitochondrial dysfunction, and inflammation play a major role in the pathophysiology of X-linked adrenoleukodystrophy (X-ALD), an inherited neurodegenerative disease caused by mutations in the ABCD1 gene, encoding the protein responsible for peroxisomal import and degradation of very long chain fatty acids (VLCFAs). Therefore, VLCFAs accumulate in tissues and plasma, constituting a pathognomonic biomarker for diagnosis. However, the precise role of VLCFA accumulation on the diverse clinical phenotypes of X-ALD and the pathogenic link between VLCFAs and oxidative stress remain currently unclear. This study proposes ferroptosis as a crucial contributor to the disease development and progression. The expression profiles of "GPX4-glutathione" and "NQO1-CoQ10" ferroptosis pathways have been analyzed in fibroblasts of one patient with AMN, the late onset and slowly progressive form of X-ALD, and in two patients with cALD, the cerebral inflammatory demyelinating form of early childhood. Furthermore, as no effective treatments are currently available, especially for the rapidly progressing form of X-ALD (cALD), the efficacy of NAC treatment has also been evaluated to open the way toward novel combined therapies. Our findings demonstrate that lipid peroxides accumulate in X-ALD fibroblasts and ferroptosis-counteracting enzymes are dysregulated, highlighting a different antioxidant response in patients with AMN and cALD.

Class A lysophosphatidic acid acyltransferase 2 from Camelina sativa promotes very long-chain fatty acids accumulation in phospholipid and triacylglycerol.

Very long-chain fatty acids (VLCFAs) are important industrial raw materials and can be produced by genetically modified oil plants. For a long time, class A lysophosphatidic acid acyltransferase (LPAT) was considered unable to promote the accumulation of VLCFA in oil crops. The bottlenecks that the transgenic high VLCFA lines have an oil content penalty and the low amount of VLCFA in phosphatidylcholine remains intractable. In the present study, a class A LPAT2 from Camelina sativa (CsaLPAT2) promoting VLCFAs accumulation in phospholipid was found. Overexpression of CsaLPAT2 alone in Arabidopsis seeds significantly increased the VLCFA content in triacylglycerol, including C20:0, C20:2, C20:3, C22:0, and C22:1. The proportion of phosphatidic acid molecules containing VLCFAs in transgenic seeds reached up to 45%, which was 2.8-fold greater than that in wild type. The proportion of phosphatidylcholine and diacylglycerol molecules containing VLCFAs also increased significantly. Seed size in CsaLPAT2 transgenic lines showed a slight increase without an oil content penalty. The total phospholipid content in the seed of the CsaLPAT2 transgenic line was significantly increased. Furthermore, the function of class A LPAT in promoting the accumulation of VLCFAs is conserved in the representative oil crops of Brassicaceae, such as C. sativa, Arabidopsis thaliana, Brassica napus, Brassica rapa, and Brassica oleracea. The findings of this study provide a promising gene resource for the production of VLCFAs.

Peroxisomal very long-chain fatty acid transport is targeted by herpesviruses and the antiviral host response

Very long-chain fatty acids (VLCFA) are critical for human cytomegalovirus replication and accumulate upon infection. Here, we used Epstein-Barr virus (EBV) infection of human B cells to elucidate how herpesviruses target VLCFA metabolism. Gene expression profiling revealed that, despite a general induction of peroxisome-related genes, EBV early infection decreased expression of the peroxisomal VLCFA transporters ABCD1 and ABCD2, thus impairing VLCFA degradation. The mechanism underlying ABCD1 and ABCD2 repression involved RNA interference by the EBV-induced microRNAs miR-9-5p and miR-155, respectively, causing significantly increased VLCFA levels. Treatment with 25-hydroxycholesterol, an antiviral innate immune modulator produced by macrophages, restored ABCD1 expression and reduced VLCFA accumulation in EBV-infected B-lymphocytes, and, upon lytic reactivation, reduced virus production in control but not ABCD1-deficient cells. Finally, also other herpesviruses and coronaviruses target ABCD1 expression. Because viral infection might trigger neuroinflammation in X-linked adrenoleukodystrophy (X-ALD, inherited ABCD1 deficiency), we explored a possible link between EBV infection and cerebral X-ALD. However, neither immunohistochemistry of post-mortem brains nor analysis of EBV seropositivity in 35 X-ALD children supported involvement of EBV in the onset of neuroinflammation. Collectively, our findings indicate a previously unrecognized, pivotal role of ABCD1 in viral infection and host defence, prompting consideration of other viral triggers in cerebral X-ALD.

A man with Erb’s disease

A man, currently aged 72, developed a spastic paraparesis without sensory abnormalities progressing to wheel-chair dependence and late urinary incontinence over 14 years. Apart from a history of type 2 diabetes mellitus, he was otherwise well. Extensive blood and CSF investigations including screening for HIV, HTLV1, syphilis, and Lyme disease were normal or negative. There was no evidence of neuropathy or denervation on EMG. MRI showed mild non-specific white matter signal change in both cerebral hemi- spheres. A provisional diagnosis of primary lateral sclerosis (PLS) was revised with the finding of elevated Very Long Chain Fatty Acids (VLCFAs). Genetic testing revealed a novel missense variant c.1771C>Gp. (Arg591Gly) in exon 7 of the ABCD1 gene. Mutation in ABCD1 transporter leads to accumulation of VLCFAs in the peroxisomes and cytosol which is toxic, causing oxidative stress and demyelination in the CNS and PNS. Literature review did not reveal reports of AMN mimicking PLS. Our patient highlights the importance of screening VLCFAs (abnormal in ~99% of men with AMN) in suspected PLS, a diagnosis of exclusion. Diagnosis of ALD/AMN allows genetic counselling, screening for adrenal failure, and access to stem cell therapy for children with asymptomatic cerebral onset ALD.sara.leddy1@nhs.net

EgMYB108 regulates very long-chain fatty acid (VLCFA) anabolism in the mesocarp of oil palm.

EgMYB108 regulates VLCFA anabolism in oil palm. Very long-chain fatty acids (VLCFAs), which are fatty acids with more than 18 C, can not only be used as a form of triglyceride (TAG) but also provide precursors for the biosynthesis of cuticle wax, and they exist in plant epidermal cells in the form of wax in higher plants. However, which and how transcriptional factors (TFs) regulate this process is largely unknown in oil palm. In this study, a MYB transcription factor (EgMYB108) with high expression in the mesocarp of oil palm fruit was characterized. Overexpression of EgMYB108 promoted not only total lipid content but also VLCFA accumulation in oil palm embryoids. Subsequently, transient transformation in protoplasts and qRT-PCR analysis indicated that the EgKCS5 and EgLACS4 genes were significantly increased with the overexpression of EgMYB108. Furthermore, yeast one‑hybrid assays, dual-luciferase assays and EMSAs demonstrated that EgMYB108 binds to the promoters of EgKCS5 and EgLACS4 and regulates their transcription. Finally, EgMYB108 interacts with the promoters of EgLACS and EgKCS simultaneously and finally improves the VLCFA and total lipid contents; a pathway summarizing this interaction was depicted.. The results provide new insight into the mechanism by which EgMYB108 regulates lipid and VLCFA accumulation in oil palm.

Nervonic Acid Attenuates Accumulation of Very Long-Chain Fatty Acids and is a Potential Therapy for Adrenoleukodystrophy.

Adrenoleukodystrophy (ALD) is an X-linked inherited peroxisomal disorder due to mutations in theALD protein and characterized by accumulation of very long-chain fatty acids (VLCFA), specifically hexacosanoic acid (C26:0). This can trigger other pathological processes such as mitochondrial dysfunction, oxidative stress, and inflammation, which if involves the brain tissues can result in a lethal form of the disease called childhood cerebral ALD. With the recent addition of ALD to the Recommended Uniform Screening Panel, there is an increase in the number of individuals who are identified with ALD. However, currently, there is no approved treatment for pre-symptomatic individuals that can arrest or delay symptom development. Here, we report our observations investigating nervonic acid, a monounsaturated fatty acid as a potential therapy for ALD. Using ALD patient-derived fibroblasts, we examined whether nervonic acid can reverse VLCFA accumulation similar to erucic acid, the active ingredient in Lorenzo's oil, a dietary intervention believed to alter disease course. We have shown that nervonic acid can reverse total lipid C26:0 accumulation in a concentration-dependent manner in ALD cell lines. Further, we show that nervonic acid can protect ALD fibroblasts from oxidative insults, presumably by increasing intracellular ATP production. Thus, nervonic acid can be a potential therapeutic for individuals with ALD, which can alter cellular biochemistry and improve its function.

Isoprostanoid Plasma Levels Are Relevant to Cerebral Adrenoleukodystrophy Disease.

Cerebral adrenoleukodystrophy (ALD) is a rare neuroinflammatory disorder characterized by progressive demyelination. Mutations within the ABCD1 gene result in very long-chain fatty acid (VLCFA) accumulation within the peroxisome, particularly in the brain. While this VLCFA accumulation is known to be the driving cause of the disease, oxidative stress can be a contributing factor. For patients with early cerebral disease, allogeneic hematopoietic stem cell transplantation (HSCT) is the standard of care, and this can be supported by antioxidants. To evaluate the involvement of fatty acid oxidation in the disease, F2-isoprostanes (F2-IsoPs), F2-dihomo-isoprostanes (F2-dihomo-IsoPs) and F4-neuroprostanes (F4-NeuroPs)—which are oxygenated metabolites of arachidonic (ARA), adrenic (AdA) and docosahexaenoic (DHA) acids, respectively—in plasma samples from ALD subjects (n = 20)—with various phenotypes of the disease-were measured. Three ALD groups were classified according to patients with: (1) confirmed diagnosis of ALD but without cerebral disease; (2) cerebral disease in early period post-HSCT (<100 days post-HSCT) and on intravenous N-acetyl-L-cysteine (NAC) treatment; (3) cerebral disease in late period post-HSCT (beyond 100 days post-HSCT) and off NAC therapy. In our observation, when compared to healthy subjects (n = 29), in ALD (i), F2-IsoPs levels were significantly (p < 0.01) increased in all patients, with the single exception of the early ALD and on NAC subjects; (ii) significant elevated (p < 0.0001) amounts of F2-dihomo-IsoPs were detected, with the exception of patients with a lack of cerebral disease; (iii), a significant increase (p < 0.003) in F4-NeuroP plasma levels was detected in all ALD patients. Moreover, F2-IsoPs plasma levels were significantly higher (p = 0.038) in early ALD in comparison to late ALD stage, and F4-NeuroPs were significantly lower (p = 0.012) in ALD subjects with a lack of cerebral disease in comparison to the late disease stage. Remarkably, plasma amounts of all investigated isoprostanoids were shown to discriminate ALD patients vs. healthy subjects. Altogether, isoprostanoids are relevant to the phenotype of X-ALD and may be helpful in predicting the presence of cerebral disease and establishing the risk of progression.