Investigation of a wide spectrum of inherited metabolic disorders by 13C NMR spectroscopy

High-resolution (1)H NMR spectroscopy of body fluids has proved to be very useful in diagnostics of inherited metabolic diseases, whereas (13)C NMR remains almost unexploited. In this paper the application of (13)C NMR spectroscopy of fivefold concentrated urine samples for diagnosis of selected metabolic diseases is reported. Various marker metabolites were identified in test urine samples from 33 patients suffering from 10 different diseases, providing information which could be crucial for their diagnoses. Spectra were accumulated for 2 h or overnight when using spectrometers operating at 9.4 or 4.7 T magnetic fields, respectively. Interpretation of the measurement results was based on a comparison of the peak positions in the measured spectrum with reference data. The paper contains a table with (13)C NMR chemical shifts of 73 standard compounds. The method can be applied individually or as an auxiliary technique to (1)H NMR or any other analytical method.     

Role of autophagy in inherited metabolic and endocrine myopathies

The prevalence of cardiometabolic disease has reached an exponential rate of rise over the last decades owing to high fat/high caloric diet intake and satiety life style. Although the presence of dyslipidemia, insulin resistance, hypertension and obesity mainly contributes to the increased incidence of cardiometabolic diseases, population-based, clinical and genetic studies have revealed a rather important role for inherited myopathies and endocrine disorders in the ever-rising metabolic anomalies. Inherited metabolic and endocrine diseases such as glycogen storage and lysosomal disorders have greatly contributed to the overall prevalence of cardiometabolic diseases. Recent evidence has demonstrated an essential role for proteotoxicity due to autophagy failure and/or dysregulation in the onset of inherited metabolic and endocrine disorders. Given the key role for autophagy in the degradation and removal of long-lived or injured proteins and organelles for the maintenance of cellular and organismal homeostasis, this mini-review will discuss the potential contribution of autophagy dysregulation in the pathogenesis of inherited myopathies and endocrine disorders, which greatly contribute to an overall rise in prevalence of cardiometabolic disorders. Molecular, clinical, and epidemiological aspects will be covered as well as the potential link between autophagy and metabolic anomalies thus target therapy may be engaged for these comorbidities.     

Laterally transferred genomic islands in Xanthomonadales related to pathogenicity and primary metabolism.

Lateral gene transfer (LGT) is considered as one of the drivers in bacterial genome evolution, usually associated with increased fitness and/or changes in behavior, especially if one considers pathogenic vs. non-pathogenic bacterial groups. The genomes of two phytopathogens, Xanthomonas campestris pv. campestris and Xanthomonas axonopodis pv. citri, were previously inspected for genome islands originating from LGT events, and, in this work, potentially early and late LGT events were identified according to their altered nucleotide composition. The biological role of the islands was also assessed, and pathogenicity, virulence and secondary metabolism pathways were functions highly represented, especially in islands that were found to be recently transferred. However, old islands are composed of a high proportion of genes related to cell primary metabolic functions. These old islands, normally undetected by traditional atypical composition analysis, but confirmed as product of LGT by atypical phylogenetic reconstruction, reveal the role of LGT events by replacing core metabolic genes normally inherited by vertical processes.     

Genistein-mediated inhibition of glycosaminoglycan synthesis, which corrects storage in cells of patients suffering from mucopolysaccharidoses, acts by influencing an epidermal growth factor-dependent pathway

Background  

Mucopolysaccharidoses (MPS) are inherited metabolic disorders caused by mutations leading to dysfunction of one of enzymes involved in degradation of glycosaminoglycans (GAGs). Due to their impaired degradation, GAGs accumulate in cells of patients, which results in dysfunction of tissues and organs. Substrate reduction therapy is one of potential treatment of these diseases. It was demonstrated previously that genistein (4', 5, 7-trihydroxyisoflavone) inhibits synthesis and reduces levels of GAGs in cultures of fibroblasts of MPS patients. Recent pilot clinical study indicated that such a therapy may be effective in MPS III (Sanfilippo syndrome).     

Inherited prion disease (PrP lysine 200) in Britain: two case reports.

OBJECTIVE--To identify cases of inherited prion diseases in Britain and to assess their phenotypic features. DESIGN--Screening study of patients suspected clinically to have Creutzfeldt-Jakob disease and other neurodegenerative diseases by prion protein gene analysis. SETTING--Biochemical research department. SUBJECTS--Patients suspected to have Creutzfeldt-Jakob disease and other neurodegenerative diseases. RESULTS--Two patients with symptoms characteristic of sporadic Creutzfeldt-Jakob disease were found to have inherited prion protein disease (PrP lysine 200), with a mutation at codon 200 of the prion protein gene. Both were homozygous at codon 129 of the gene. One patient was a man aged 58 of British descent while the other was of Libyan Jewish origin. CONCLUSION--Two foci of inherited prion disease are known, among Libyan Jews and in Slovakia. A separate British focus of the disease may also exist. Heterozygosity at codon 129 may lead to reduced penetrance of the mutation.     

Mucopolysaccharidoses--biochemical mechanisms of diseases and therapeutic possibilities

Mucopolysaccharidoses (MPS) are inherited metabolic diseases from the group of lysosomal storage disorders (LSD). They are caused by genetic defects resulting in the absence or severe deficiency in one of lysosmal hydrolases involved in degradation of glycosaminoglycans (GAG). Partially degraded GAGs are accumulated in lysosomes, causing dysfunction of cells, tissues and organs. Last years did bring some breakthrough discoveries, which were important to understand biochemical mechanisms of MPS appearance and course, as well as to develop therapeutic procedures for these inherited metabolic disorders.     

Successful prediction of substrate-binding pocket in SLC17 transporter sialin

Secondary active transporters from the SLC17 protein family are required for excitatory and purinergic synaptic transmission, sialic acid metabolism, and renal function, and several members are associated with inherited neurological or metabolic diseases. However, molecular tools to investigate their function or correct their genetic defects are limited or absent. Using structure-activity, homology modeling, molecular docking, and mutagenesis studies, we have located the substrate-binding site of sialin (SLC17A5), a lysosomal sialic acid exporter also recently implicated in exocytotic release of aspartate. Human sialin is defective in two inherited sialic acid storage diseases and is responsible for metabolic incorporation of the dietary nonhuman sialic acid N-glycolylneuraminic acid. We built cytosol-open and lumen-open three-dimensional models of sialin based on weak, but significant, sequence similarity with the glycerol-3-phosphate and fucose permeases from Escherichia coli, respectively. Molecular docking of 31 synthetic sialic acid analogues to both models was consistent with inhibition studies. Narrowing the sialic acid-binding site in the cytosol-open state by two phenylalanine to tyrosine mutations abrogated recognition of the most active analogue without impairing neuraminic acid transport. Moreover, a pilot virtual high-throughput screening of the cytosol-open model could identify a pseudopeptide competitive inhibitor showing >100-fold higher affinity than the natural substrate. This validated model of human sialin and sialin-guided models of other SLC17 transporters should pave the way for the identification of inhibitors, glycoengineering tools, pharmacological chaperones, and fluorescent false neurotransmitters targeted to these proteins.     

Peroxisome biogenesis disorders: genetics and cell biology

Zellweger syndrome, neonatal adrenoleukodystrophy, infantile Refsum disease and rhizomelic chondrodysplasia punctata are progressive disorders characterized by loss of multiple peroxisomal metabolic functions. These diseases are inherited in an autosomal recessive manner, are caused by defects in the import of peroxisomal matrix proteins and are referred to as the peroxisome biogenesis disorders (PBDs). Recent studies have identified the PEX genes that are mutated in 11 of the 12 known complementation groups of PBD patients. This article reviews these advances in PBD genetics and discusses how studies of human PEX genes, their protein products and PBD cell lines are shaping current models of peroxisome biogenesis.     

Simultaneous retention index analysis of urinary amino acids and carboxylic acids for graphic recognition of abnormal state

Simultaneous profiling analysis of urinary amino acids (AAs) and carboxylic acids (CAs) was combined with retention index (I) analysis for graphic recognition of abnormal metabolic state. The temperature-programmed I values of the AA and CA standards measured as ethoxycarbonyl (EOC)/methoxime (MO)/tert-butyldimethylsilyl (TBDMS) derivatives were used as the reference I values. Urine samples were subjected to the sequential EOC, MO and TBDMS reactions for the analysis by gas chromatography (GC) and GC-mass spectrometry. The complex GC profiles were then transformed into their respective I patterns in bar graphic forms by plotting the normalized peak area ratios (%) of the identified AAs and CAs against their reference I values as the identification numbers. When the present method was applied to infant urine specimens from normal controls and patients with inherited metabolic diseases such as phenylketonuria, maple syrup urine disease, methylmalonic aciduria or isovaleric aciduria, each I pattern of bar graph more distinctly displayed quantitative abundances of urinary AAs and CAs in qualitative I scale, thus allowing graphic discrimination between normal and abnormal states.     

ALG1-CDG: A new case with early fatal outcome

Congenital disorders of glycosylation (CDG) are a growing group of inherited metabolic disorders where enzymatic defects in the formation or processing of glycolipids and/or glycoproteins lead to variety of different diseases.     

Quantitative Analysis of Orotic Acid in Urine by RP-HPLC

Abstract

we describe a new RP-HPLC assay to measure orotate concentration in urine. The method is rapid, sensitive and precise. It is particularly suitable for the diagnosis of inherited metabolic diseases and deranged orotate metabolism.     

Therapies and therapeutic approaches in Congenital Disorders of Glycosylation

Inborn errors in glycoconjugate biosynthesis termed ‘Congenital Disorders of Glycosylation’ (CDG) comprise a rapidly expanding group of metabolic diseases in man. Up till now more than 60 different inherited disorders in N- and O-glycosylation pathways have been identified. They affect the biosynthesis of glycan moieties linked to proteins as well as lipids. Due to failures in protein glycosylation, CDG patients suffer from multi systemic disorders, which mostly present with severe psychomotor and mental retardations, muscular impairment, ataxia, failure to thrive and developmental delay. Although improved biochemical and genetic investigations led to identification of a variety of new molecular defects in glycoconjugate biosynthesis, effective therapies for most types of the CDG are so far not available. Therefore, intensive investigations on treatment options for this group of diseases have been carried out in recent years.     

l-carnitine supplementation as a potential antioxidant therapy for inherited neurometabolic disorders

In recent years increasing evidence has emerged suggesting that oxidative stress is involved in the pathophysiology of a number of inherited metabolic disorders. However the clinical use of classical antioxidants in these diseases has been poorly evaluated and so far no benefit has been demonstrated. l-Carnitine is an endogenous substance that acts as a carrier for fatty acids across the inner mitochondrial membrane necessary for subsequent beta-oxidation and ATP production. Besides its important role in the metabolism of lipids, l-carnitine is also a potent antioxidant (free radical scavenger) and thus may protect tissues from oxidative damage. This review addresses recent findings obtained from patients with some inherited neurometabolic diseases showing that l-carnitine may be involved in the reduction of oxidative damage observed in these disorders. For some of these diseases, reduced concentrations of l-carnitine may occur due to the combination of this compound to the accumulating toxic metabolites, especially organic acids, or as a result of protein restricted diets. Thus, l-carnitine supplementation may be useful not only to prevent tissue deficiency of this element, but also to avoid oxidative damage secondary to increased production of reactive species in these diseases. Considering the ability of l-carnitine to easily cross the blood–brain barrier, l-carnitine supplementation may also be beneficial in preventing neurological damage derived from oxidative injury. However further studies are required to better explore this potential.     

Chaperone Therapy for GM2 Gangliosidosis: Effects of Pyrimethamine on β-Hexosaminidase Activity in Sandhoff Fibroblasts

Sphingolipidoses are inherited genetic diseases due to mutations in genes encoding proteins involved in the lysosomal catabolism of sphingolipids. Despite a low incidence of each individual disease, altogether, the number of patients involved is relatively high and resolutive approaches for treatment are still lacking. The chaperone therapy is one of the latest pharmacological approaches to these storage diseases. This therapy allows the mutated protein to escape its natural removal and to increase its quantity in lysosomes, thus partially restoring the metabolic functions. Sandhoff disease is an autosomal recessive inherited disorder resulting from β-hexosaminidase deficiency and characterized by large accumulation of GM2 ganglioside in brain. No enzymatic replacement therapy is currently available, and the use of inhibitors of glycosphingolipid biosynthesis for substrate reduction therapy, although very promising, is associated with serious side effects. The chaperone pyrimethamine has been proposed as a very promising drug in those cases characterized by a residual enzyme activity. In this review, we report the effect of pyrimethamine on the recovery of β-hexosaminidase activity in cultured fibroblasts from Sandhoff patients.     

活体生物药的应用及在遗传性代谢缺陷病治疗中的展望

活体生物药(live biotherapeutic products,LBPs)是指来自于人体肠道内或自然界中能够治疗人类疾病的活性菌。但天然筛选的活菌存在治疗效果不明显、差异性较大等缺点,难以满足个性化诊疗的需要。近年来,随着合成生物学的发展,研究者利用生命科学及工程科学手段,设计并构建了若干可响应外界复杂环境信号的工程菌株,加快了活体生物药的研发和应用过程。遗传性代谢缺陷病(inherited metabolic disease)是因体内某些酶的遗传缺陷致使体内相应的代谢物不能正常代谢而引发一系列临床症状的一类疾病,因此利用合成生物学技术,针对特定缺陷的酶设计重组活体生物药,未来有希望用于遗传性代谢缺陷病的治疗。本综述以活体生物药为切入点,并结合国内外文献综述,来探讨活体生物药在疾病治疗中的应用,以及对遗传性代谢缺陷病治疗的潜力。     

Application of in silico positional cloning and bioinformatic mutation analysis to the study of eye diseases

A vast amount of DNA and protein sequence is now available and a plethora of programs have been developed to analyse the data. The bewildering variety of analyses that can be performed via the World-Wide Web can deter researchers from applying bioinformatics to augment their traditional genetic research. Focusing on the inherited eye diseases, this paper provides a guide to the appropriate software required for identification of candidate genes through to the detection and analysis of mutations.     

Genetic therapies for RNA mis-splicing diseases

RNA mis-splicing diseases account for up to 15% of all inherited diseases, ranging from neurological to myogenic and metabolic disorders. With greatly increased genomic sequencing being performed for individual patients, the number of known mutations affecting splicing has risen to 50-60% of all disease-causing mutations. During the past 10years, genetic therapy directed toward correction of RNA mis-splicing in disease has progressed from theoretical work in cultured cells to promising clinical trials. In this review, we discuss the use of antisense oligonucleotides to modify splicing as well as the principles and latest work in bifunctional RNA, trans-splicing and modification of U1 and U7 snRNA to target splice sites. The success of clinical trials for modifying splicing to treat Duchenne muscular dystrophy opens the door for the use of splicing modification for most of the mis-splicing diseases.     

A review of physiological and metabolic effects of essential amino acids

Summary The authors review ten essential amino acids with regard to their metabolic, physiologic and therapeutic effects throughout the human body. Physical properties of these biologically active compounds are discussed as a foundation for their diverse roles in special nitrogen containing products, neurotransmitters, and as alternative energy sources. Both normal and abnormal amino acid metabolism are considered in the areas of digestion, elimination of metabolic products, metabolic intermediates, and defects in these systems. Recent developments in therapeutic applications are further examined for clinical utility and as an economical alternative to traditional clinical treatment modalities.     

Metabolic syndrome in rheumatic diseases: epidemiology,pathophysiology, and clinical implications

Subjects with metabolic syndrome–a constellation of cardiovascular risk factors of which central obesity and insulin resistance are the most characteristic–are at increased risk for developing diabetes mellitus and cardiovascular disease. In these subjects, abdominal adipose tissue is a source of inflammatory cytokines such as tumor necrosis factor-alpha, known to promote insulin resistance. The presence of inflammatory cytokines together with the well-documented increased risk for cardiovascular diseases in patients with inflammatory arthritides and systemic lupus erythematosus has prompted studies to examine the prevalence of the metabolic syndrome in an effort to identify subjects at risk in addition to that conferred by traditional cardiovascular risk factors. These studies have documented a high prevalence of metabolic syndrome which correlates with disease activity and markers of atherosclerosis. The correlation of inflammatory disease activity with metabolic syndrome provides additional evidence for a link between inflammation and metabolic disturbances/vascular morbidity.