Aldh1l2 knockout mouse metabolomics links the loss of the mitochondrial folate enzyme to deregulation of a lipid metabolism observed in rare human disorder.

BACKGROUND: Mitochondrial folate enzyme ALDH1L2 (aldehyde dehydrogenase 1 family member L2) converts 10-formyltetrahydrofolate to tetrahydrofolate and CO2 simultaneously producing NADPH. We have recently reported that the lack of the enzyme due to compound heterozygous mutations was associated with neuro-ichthyotic syndrome in a male patient. Here, we address the role of ALDH1L2 in cellular metabolism and highlight the mechanism by which the enzyme regulates lipid oxidation. METHODS: We generated Aldh1l2 knockout (KO) mouse model, characterized its phenotype, tissue histology, and levels of reduced folate pools and applied untargeted metabolomics to determine metabolic changes in the liver, pancreas, and plasma caused by the enzyme loss. We have also used NanoString Mouse Inflammation V2 Code Set to analyze inflammatory gene expression and evaluate the role of ALDH1L2 in the regulation of inflammatory pathways. RESULTS: Both male and female Aldh1l2 KO mice were viable and did not show an apparent phenotype. However, H&E and Oil Red O staining revealed the accumulation of lipid vesicles localized between the central veins and portal triads in the liver of Aldh1l2-/- male mice indicating abnormal lipid metabolism. The metabolomic analysis showed vastly changed metabotypes in the liver and plasma in these mice suggesting channeling of fatty acids away from ß-oxidation. Specifically, drastically increased plasma acylcarnitine and acylglycine conjugates were indicative of impaired ß-oxidation in the liver. Our metabolomics data further showed that mechanistically, the regulation of lipid metabolism by ALDH1L2 is linked to coenzyme A biosynthesis through the following steps. ALDH1L2 enables sufficient NADPH production in mitochondria to maintain high levels of glutathione, which in turn is required to support high levels of cysteine, the coenzyme A precursor. As the final outcome, the deregulation of lipid metabolism due to ALDH1L2 loss led to decreased ATP levels in mitochondria. CONCLUSIONS: The ALDH1L2 function is important for CoA-dependent pathways including ß-oxidation, TCA cycle, and bile acid biosynthesis. The role of ALDH1L2 in the lipid metabolism explains why the loss of this enzyme is associated with neuro-cutaneous diseases. On a broader scale, our study links folate metabolism to the regulation of lipid homeostasis and the energy balance in the cell.

1-O-Alkylglycerol accumulation reveals abnormal ether glycerolipid metabolism in Sjögren-Larsson syndrome.

Sjögren-Larsson syndrome (SLS) is an inherited metabolic disease characterized by ichthyosis, spasticity, intellectual disability and deficient oxidation and accumulation of of fatty aldehydes and alcohols. We investigated whether excess fatty alcohols in SLS are diverted into biosynthesis of ether glycerolipids (eGLs) by measuring the 1-O-alkylglycerol (AG) backbone of eGLs in stratum corneum, plasma and red blood cells (RBCs). In all tissues, saturated and monounsaturated AGs were detected. In stratum corneum from SLS patients, saturated AGs (C15-C20) were increased 97-fold (range: 86- to 169-fold) compared to controls. AGs were largely (67 ± 9%) derived from neutral esterified eGLs (i.e. alkyl-diacylglyerol) and free non-esterified AGs (28 ± 10%), but very little from plasmalogens (3 ± 5%). Plasma from SLS patients had 2-fold more C18:0-AG (p < 0.005) and 40% less C16:1-AG (p < 0.01) than controls but the total concentration of AGs was not increased, and the AG profile in RBCs from SLS subjects was normal. All AGs were profoundly reduced in plasma and RBCs from patients with Zellweger spectrum disorder, who have impaired eGL (i.e. plasmalogen) synthesis. The striking accumulation of AGs in stratum corneum of SLS patients constitutes a novel lipid biomarker for this disease, and may contribute to the pathogenesis of the ichthyosis. Measurement of AGs is a simple and convenient method to assess global synthesis of eGLs and potentially identify patients with defects in their metabolism.

Disturbed brain ether lipid metabolism and histology in Sjögren-Larsson syndrome.

Sjögren-Larsson syndrome (SLS) is a rare neurometabolic syndrome caused by deficient fatty aldehyde dehydrogenase. Patients exhibit intellectual disability, spastic paraplegia, and ichthyosis. The accumulation of fatty alcohols and fatty aldehydes has been demonstrated in plasma and skin but never in brain. Brain magnetic resonance imaging and spectroscopy studies, however, have shown an abundant lipid peak in the white matter of patients with SLS, suggesting lipid accumulation in the brain as well. Using histopathology, mass spectrometry imaging, and lipidomics, we studied the morphology and the lipidome of a postmortem brain of a 65-year-old female patient with genetically confirmed SLS and compared the results with a matched control brain. Histopathological analyses revealed structural white matter abnormalities with the presence of small lipid droplets, deficient myelin, and astrogliosis. Biochemically, severely disturbed lipid profiles were found in both white and gray matter of the SLS brain, with accumulation of fatty alcohols and ether lipids. Particularly, long-chain unsaturated ether lipid species accumulated, most prominently in white matter. Also, there was a striking accumulation of odd-chain fatty alcohols and odd-chain ether(phospho)lipids. Our results suggest that the central nervous system involvement in SLS is caused by the accumulation of fatty alcohols leading to a disbalance between ether lipid and glycero(phospho)lipid metabolism resulting in a profoundly disrupted brain lipidome. Our data show that SLS is not a pure leukoencephalopathy, but also a gray matter disease. Additionally, the histopathological abnormalities suggest that astrocytes and microglia might play a pivotal role in the underlying disease mechanism, possibly contributing to the impairment of myelin maintenance.

Comprehensive Molecular Profiles of Functionally Effective MSC-Derived Extracellular Vesicles in Immunomodulation.

Accumulating evidence indicates that mesenchymal stem/stromal cell-derived extracellular vesicles (MSC-EVs) exhibit immunomodulatory effects by delivering therapeutic RNAs and proteins; however, the molecular mechanism underlying the EV-mediated immunomodulation is not fully understood. In this study, we found that EVs from early-passage MSCs had better immunomodulatory potency than did EVs from late-passage MSCs in T cell receptor (TCR)- or Toll-like receptor 4 (TLR4)-stimulated splenocytes and in mice with ocular Sjögren's syndrome. Moreover, MSC-EVs were more effective when produced from 3D culture of the cells than from the conventional 2D culture. Comparative molecular profiling using proteomics and microRNA sequencing revealed the enriched factors in MSC-EVs that were functionally effective in immunomodulation. Among them, manipulation of transforming growth factor ß1 (TGF-ß1), pentraxin 3 (PTX3), let-7b-5p, or miR-21-5p levels in MSCs significantly affected the immunosuppressive effects of their EVs. Furthermore, there was a strong correlation between the expression levels of TGF-ß1, PTX3, let-7b-5p, or miR-21-5p in MSC-EVs and their suppressive function. Therefore, our comparative strategy identified TGF-ß1, PTX3, let-7b-5p, or miR-21-5p as key molecules mediating the therapeutic effects of MSC-EVs in autoimmune disease. These findings would help understand the molecular mechanism underlying EV-mediated immunomodulation and provide functional biomarkers of EVs for the development of robust EV-based therapies.

Sjögren-Larsson syndrome: a complex metabolic disease with a distinctive ocular phenotype.

Purpose: Sjögren-Larsson Syndrome (SLS) is a rare genetic disorder characterized by a distinctive crystalline maculopathy, congenital ichthyosis, spasticity and intellectual disability. We review the genetic, biochemical and clinical aspects of SLS with a particular focus on the ophthalmologic features of the disease.Methods: Published reports of SLS are combined with clinical experience to provide an overview of this disease.Results: SLS is caused by bi-allelic mutations in ALDH3A2, which codes for fatty aldehyde dehydrogenase, a key enzyme needed for the metabolism of long-chain aliphatic aldehydes and alcohols. SLS patients display perifoveal crystalline inclusions (glistening white dots) that appear in early childhood, vary from sparse to florid and are located in the inner retina. Other findings include retinal thinning, cystic macular degeneration, retinal pigment epithelium atrophy and deficiency of macular pigment. Photophobia is common. Visual evoked potentials are often absent or delayed, whereas electroretinography studies are usually normal. Mild-moderate deficits in visual acuity are common but vision is usually preserved into adulthood. The maculopathy is thought to be due to the accumulation of fatty aldehydes and/or alcohols, which alter membrane function. Defective macular pigment metabolism may also contribute to a unique susceptibility to photo-oxidative damage in the retina.Conclusions: The distinctive retinal phenotype, together with the neurologic and cutaneous symptoms, allows the ophthalmologist to reliably diagnose SLS. Although no effective treatment exists for the ocular symptoms, emerging insight into the pathogenic mechanisms at play in the eye promises to bring effective therapy for SLS in the future.

Síndrome de Sjögren-Larsson: Reporte de caso pediátrico / Sjögren-Larsson syndrome: Pediatric case report

El síndrome de Sjogren-Larsson se caracteriza por retardo mental, ictiosis congènita y diplejía o cuadriplejía espástica. El defecto primario en este síndrome es la mutación del gen ALDH3A2, que codifica la enzima aldehído deshidrogenasa grasa y causa una deficiencia enzimática que produce una acumulación de alcoholes y aldehídos grasos en los tejidos que comprometen la integridad de la membrana celular, cuyos efectos pueden observarse en la piel, los ojos y el sistema nervioso central. El diagnóstico se realiza por medio de la cuantificación de la actividad de la enzima. Se describe el caso de una paciente con signos clínicos patognomónicos del síndrome de Sjogren-Larsson, cuyo diagnóstico se realizó por medio de la cuantificación de la actividad enzimática en un cultivo de fibroblastos. Además, tomando en cuenta el árbol genealógico de la paciente, se realizó el estudio en los padres y un hermano con signos sugestivos del síndrome de Sjogren-Larsson.

Sjogren-Larsson syndrome is characterized by congenital ichthyosis, mental retardation and spastic diplegia or quadriplegia. The primary defect in this syndrome is mutation of ALDH3A2 gen that codes for the fatty aldehyde dehydrogenase. Deficiency of this enzyme causes an accumulation of fatty alcohols and fatty aldehydes, leading to altered cell-membrane integrity. Skin, eyes, and the central nervous system are affected latter. The diagnosis is carried out through the cuantification of the enzyme activity.

Late-Stage Sjögren-Larsson Syndrome Maculopathy Imaged With OCT Angiography.

Three adult siblings with Sjögren-Larsson syndrome (SLS) demonstrated signs of late-stage SLS maculopathy, including intraretinal crystals, atrophic changes, and lipofuscin deposition. This first report of SLS maculopathy imaged with optical coherence tomography angiography revealed decreased retinal capillary density, vessel dilation, and increased flow voids in the superficial and deep capillary plexuses. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:e78-e82.].

Sequence variants in nine different genes underlying rare skin disorders in 10 consanguineous families.

BACKGROUND: Genodermatoses represent genetic anomalies of skin tissues including hair follicles, sebaceous glands, eccrine glands, nails, and teeth. Ten consanguineous families segregating various genodermatosis phenotypes were investigated in the present study. METHODS: Homozygosity mapping, exome, and Sanger sequencing were employed to search for the disease-causing variants in the 10 families. RESULTS: Exome sequencing identified seven homozygous sequence variants in different families, including: c.27delT in FERMT1; c.836delA in ABHD5; c.2453C>T in ERCC5; c.5314C>T in COL7A1; c.1630C>T in ALOXE3; c.502C>T in PPOX; and c.10G>T in ALDH3A2. Sanger sequencing revealed three homozygous variants: c.1718 + 2A>G in FERMT1; c.10459A>T in FLG; and c.92delT in the KRT14 genes as the underlying genetic cause of skin phenotypes. CONCLUSION: This study supports the use of exome sequencing as a powerful, efficient tool for identifying genes that underlie rare monogenic skin disorders.

Intrathecal Baclofen Therapy for the Treatment of Spasticity in Sjögren-Larsson Syndrome.

Intrathecal baclofen therapy is widely accepted as a treatment option for patients with severe spasticity. The current treatment of spasticity in patients with Sjögren-Larsson syndrome is largely symptomatic, given that no effective causal therapy treatments are available. We report the outcome of 2 patients with Sjögren-Larsson syndrome who had pump implantation for intrathecal baclofen. We observed a positive response, with a decrease of spasticity, reflecting in the Modified Ashworth Scale, and parents and caregivers observed a functional improvement in both patients. One patient experienced skin irritation 15 months after surgery, necessitating pump repositioning. No infection occurred. Our report shows that intrathecal baclofen therapy can have a positive therapeutic effect on spasticity in patients with Sjögren-Larsson syndrome, and therefore may be a promising addition to current treatments.

Unusual presentation Of Sjögren-associated neuropathy with plasma cell-rich infiltrate.

INTRODUCTION: Sjögren syndrome is thought to be a lymphocyte-driven process. Peripheral nervous system involvement occurs in about 20%-25% of patients. A sensory-predominant, large-fiber peripheral neuropathy is most common, and it is usually associated with a subacute to chronic presentation. METHODS: We report a rare case of an acute Sjögren-associated, sensory predominant, length-dependent peripheral neuropathy mimicking Guillain-Barré syndrome. The patient presented with sensory ataxia preceded by fever and polyarthralgia. She gave a history of years of dry eyes and dry mouth. RESULTS: She had a positive Shirmer test, abnormal salivary gland scan, and positive SS-A and SS-B antibodies. A sural nerve biopsy showed an unusual, dense, non-IgG4, polyclonal, plasma-cell perivascular infiltrate. The patient responded to treatment with weekly pulse intravenous methylprednisolone. CONCLUSIONS: Sjögren syndrome can present with acute-onset, sensory predominant peripheral neuropathy. The role of plasma cells in Sjögren syndrome is unexplored and deserves further study. Muscle Nerve 55: 605-608, 2017.

Inherited ichthyosis: Syndromic forms.

Among diseases that cause ichthyosis as one of the symptoms, there are some diseases that induce abnormalities in organs other than the skin. Of these, diseases with characteristic signs are regarded as syndromes. Although these syndromes are very rare, Netherton syndrome, Sjögren-Larsson syndrome, Conradi-Hünermann-Happle syndrome, Dorfman-Chanarin syndrome, ichthyosis follicularis, atrichia and photophobia (IFAP) syndrome, and Refsum syndrome have been described in texts as representative ones. It is important to know the molecular genetics and pathomechanisms in order to establish an effective therapy and beneficial genetic counseling including a prenatal diagnosis.

Ocular manifestations of genetic skin disorders.

Genetic skin diseases, or genodermatoses, often have extracutaneous manifestations. Ocular manifestations in particular can have significant clinical implications, like blindness. Other manifestations, such as the corneal opacities that occur in X-linked ichthyosis, are asymptomatic but characteristic of a particular genodermatosis. Ophthalmologic examination can aid in diagnosis when characteristic findings are seen. The genodermatoses with ocular manifestations will be reviewed, but neurocutaneous, syndromes, genetic pigmentary disorders, and genetic metabolic diseases are not included because they are covered elsewhere in this issue.

Ictiosis sindrómicas / Syndromic ichthyosis

Las ictiosis hereditarias son un grupo de desórdenes mendelianos, con manifestaciones clínicas y alteraciones genéticas heterogéneas caracterizadas por la presencia de escamas y/o hiperqueratosis. Las ictiosis sindrómicas son aquellas en las que el defecto genético se manifiesta en la piel y también en otros órganos. Presentamos 7 pacientes con ictiosis sindrómicas: un síndrome IFAP (ictiosis folicular, atriquia, fotofobia), un síndrome de Conradi-Hünermann-Happle (CHH), dos síndromes de Netherton (SN), dos síndromes de Sjögren-Larsson (SSL) y un síndrome KID (queratitis, ictiosis, sordera). Se analizan las características clínicas y diagnósticas de nuestros pacientes (AU)

Inherited ichthyosis are a group of clinical and genetic heterogeneous disorders characterized by the presence of scales, hyperkeratosis or both. In syndromic ichthyosis, the genetic defect involves the skin and other organs. We present 7 patients with syndromic ichthyosis: a case of IFAP syndrome (ichthyosis follicularis with alopecia and photophobia), a case of Conradi-Hünermann-Happle (CHH) syndrome, two cases of Netherton syndrome, two cases of Sjögren-Larsson syndrome and a case of KID syndrome (keratitis, ichthyosis and deafness). We analyze the diagnostic and clinical features of our patients (AU)

Changes in the Submandibular Salivary Gland Epithelial Cell Subpopulations During Progression of Sjögren's Syndrome-Like Disease in the NOD/ShiLtJ Mouse Model.

Sjögren's syndrome (SS), an autoimmune exocrinopathy, is associated with dysfunction of the secretory salivary gland epithelium, leading to xerostomia. The etiology of SS disease progression is poorly understood as it is typically not diagnosed until late stage. Since mouse models allow the study of disease progression, we investigated the NOD/ShiLtJ mouse to explore temporal changes to the salivary epithelium. In the NOD/ShiLtJ model, SS presents secondary to autoimmune diabetes, and SS disease is reportedly fully established by 20 weeks. We compared epithelial morphology in the submandibular salivary glands (SMG) of NOD/ShiLtJ mice with SMGs from the parental strain at 12, 18, and 22 weeks of age and used immunofluorescence to detect epithelial proteins, including the acinar marker, aquaporin 5, ductal cell marker, cytokeratin 7, myoepithelial cell marker, smooth muscle α-actin, and the basal cell marker, cytokeratin 5, while confirming immune infiltrates with CD45R. We also compared these proteins in the labial salivary glands of human SS patients with control tissues. In the NOD/ShiLtJ SMG, regions of lymphocytic infiltrates were not associated with widespread epithelial tissue degradation; however, there was a decrease in the area of the gland occupied by secretory epithelial cells in favor of ductal epithelial cells. We observed an expansion of cells expressing cytokeratin 5 within the ducts and within the smooth muscle α-actin(+) basal myoepithelial population. The altered acinar/ductal ratio within the NOD/ShiLtJ SMG likely contributes to salivary hypofunction, while the expansion of cytokeratin 5 positive-basal cells may reflect loss of function or indicate a regenerative response.

Method to simultaneously determine the sphingosine 1-phosphate breakdown product (2E)-hexadecenal and its fatty acid derivatives using isotope-dilution HPLC-electrospray ionization-quadrupole/time-of-flight mass spectrometry.

Sphingosine 1-phosphate (S1P), a bioactive lipid involved in various physiological processes, can be irreversibly degraded by the membrane-bound S1P lyase (S1PL) yielding (2E)-hexadecenal and phosphoethanolamine. It is discussed that (2E)-hexadecenal is further oxidized to (2E)-hexadecenoic acid by the long-chain fatty aldehyde dehydrogenase ALDH3A2 (also known as FALDH) prior to activation via coupling to coenzyme A (CoA). Inhibition or defects in these enzymes, S1PL or FALDH, result in severe immunological disorders or the Sjögren-Larsson syndrome, respectively. Hence, it is of enormous importance to simultaneously determine the S1P breakdown product (2E)-hexadecenal and its fatty acid metabolites in biological samples. However, no method is available so far. Here, we present a sensitive and selective isotope-dilution high performance liquid chromatography-electrospray ionization-quadrupole/time-of-flight mass spectrometry method for simultaneous quantification of (2E)-hexadecenal and its fatty acid metabolites following derivatization with 2-diphenylacetyl-1,3-indandione-1-hydrazone and 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide. Optimized conditions for sample derivatization, chromatographic separation, and MS/MS detection are presented as well as an extensive method validation. Finally, our method was successfully applied to biological samples. We found that (2E)-hexadecenal is almost quantitatively oxidized to (2E)-hexadecenoic acid, that is further activated as verified by cotreatment of HepG2 cell lysates with (2E)-hexadecenal and the acyl-CoA synthetase inhibitor triacsin C. Moreover, incubations of cell lysates with deuterated (2E)-hexadecenal revealed that no hexadecanoic acid is formed from the aldehyde. Thus, our method provides new insights into the sphingolipid metabolism and will be useful to investigate diseases known for abnormalities in long-chain fatty acid metabolism, e.g., the Sjögren-Larsson syndrome, in more detail.

Sjögren-Larsson syndrome: phenotypic variability in two brothers with a neurocutaneous disorder.

Sjögren-Larsson syndrome (SLS) is a rare autosomal recessively inherited neurocutaneous disorder caused by mutations in the ALDH3A2 gene that encodes fatty aldehyde dehydrogenase, an enzyme that catalyzes the oxidation of fatty aldehyde to fatty acid. It is characterized by an unusual combination of cutaneous and neurologic signs and symptoms. The authors describe two brothers of consanguineous parents with SLS, one of whom was born from a dizygotic twin pregnancy (with an apparently normal sister), and they focus on the variability of the clinical findings of the syndrome even among siblings and twins.

Sjögren-Larsson syndrome: novel mutations in the ALDH3A2 gene in a French cohort.

Sjogren-Larsson syndrome (SLS) is a rare autosomal recessive disorder characterized by ichthyosis, spastic di- or tetraplegia and mental retardation due a defect of the fatty aldehyde dehydrogenase (FALDH), related to mutations in the ALDH3A2 gene. In this study, we screened a French cohort of patients with Sjögren-Larsson syndrome (SLS) for mutations in the ALDH3A2 gene. The five unrelated patients with typical SLS all present mutations in this gene. Three novel mutations were identified whereas three other ones were previously described. We also realized functional analyses at the mRNA level for two splice site mutations to study their deleterious consequences. Two of the previously described mutations had already been identified in the same region of Europe, suggesting a putative founder effect. We suggest that, (1) when clinical and MR features are present, direct sequencing of the ALDH3A2 gene in SLS is of particular interest without necessity of a skin biopsy for enzymatic assay in order to propose genetic counsel and (2) identification of mutations already described in the same population with putative founder effects may simplify genetic analysis in this context.

Síndrome Sjögren - Larsson / Sjögren - Larsson syndrome

Relatam-se os casos de dois irmãos consanguíneos com síndrome de Sjögren- Larsson, enfatizando a importância clínica do exame oftalmológico. BPLS, masculino, 11 anos e MBLS, feminino, 10 anos, irmãos de pais não-consanguíneos, apresentando ictiose congênita, diplegia espástica e retardo mental. Ao exame oftalmológico, apresentavam miopia, fotofobia, baixa acuidade visual. A fundoscopia, presença de cristais branco-amarelados em área foveal e parafoveal em ambos os olhos. Aconselhamento genético foi realizado. O manejo foi de suporte. A Síndrome de Sjögren-Larsson é uma rara doença autossômica recessiva em que há 100 por cento de penetrância. Síndrome de Sjögren-Larsson é classicamente caracterizada por ictiose, espasticidade e deficiência mental. A doença é causada por mutações no gene aldeído desidrogenase. As alterações oculares observadas são geralmente bilaterais, cristais branco-amarelados em área retiniana, que aparecem nos dois primeiros anos de vida e que vão aumentando em número com a idade. As anormalidades oculares não têm relação com a severidade da ictiose ou com as anormalidades neurológicas. Acredita-se que as lesões oftalmológicas sejam um sinal patognomônico da síndrome. É necessário enfatizar a importância do diagnóstico precoce e possibilidades de tratamento dietético.

Sjogren - Larsson syndrome is a rare autosomal recessively inherited neurocutaneous disorder which occurs with 100 percent penetrance and is classically characterized by ichthyosis, spasticity and mental handicap. The disease is caused by mutations in the aldehyde dehydrogenase gene. The ocular manifestations are highly characteristic bilateral, glistening yellow-white retinal dots from the age of 1 to 2 years onward. The number of dots increases whit age. The extent of the macular abnormality does not correlate with the severity of the ichthyosis or with the severity of the neurological abnormalities. We report the clinical characteristics and ocular manifestations associated with the Sjögren-Larsson syndrome in two siblings, emphasizing the clinical importance of the ophthalmological examination of the Sjögren-Larsson syndrome. BPLS, a eleven year old boy and MPLS, a ten year old girl from non-consanguinous parents, presenting congenital ichthyosis, spastic diplegia and mental retardation. Miopia, fotofobia, subnormal visual acuity and glistening yellow-white crystalline deposits that were located in the foveal and parafoveal area were found in the ophthalmologic examination.