Mutations in EXTL3 Cause Neuro-immuno-skeletal Dysplasia Syndrome.

EXTL3 regulates the biosynthesis of heparan sulfate (HS), important for both skeletal development and hematopoiesis, through the formation of HS proteoglycans (HSPGs). By whole-exome sequencing, we identified homozygous missense mutations c.1382C>T, c.1537C>T, c.1970A>G, and c.2008T>G in EXTL3 in nine affected individuals from five unrelated families. Notably, we found the identical homozygous missense mutation c.1382C>T (p.Pro461Leu) in four affected individuals from two unrelated families. Affected individuals presented with variable skeletal abnormalities and neurodevelopmental defects. Severe combined immunodeficiency (SCID) with a complete absence of T cells was observed in three families. EXTL3 was most abundant in hematopoietic stem cells and early progenitor T cells, which is in line with a SCID phenotype at the level of early T cell development in the thymus. To provide further support for the hypothesis that mutations in EXTL3 cause a neuro-immuno-skeletal dysplasia syndrome, and to gain insight into the pathogenesis of the disorder, we analyzed the localization of EXTL3 in fibroblasts derived from affected individuals and determined glycosaminoglycan concentrations in these cells as well as in urine and blood. We observed abnormal glycosaminoglycan concentrations and increased concentrations of the non-sulfated chondroitin disaccharide D0a0 and the disaccharide D0a4 in serum and urine of all analyzed affected individuals. In summary, we show that biallelic mutations in EXTL3 disturb glycosaminoglycan synthesis and thus lead to a recognizable syndrome characterized by variable expression of skeletal, neurological, and immunological abnormalities.

Plasma and urinary glycosaminoglycans in the course of juvenile idiopathic arthritis.

OBJECTIVES: The aim of the study was to perform analyses of plasma and urinary glycosaminoglycan isolated from juvenile idiopathic arthritis (JIA). METHODS, RESULTS: Chondroitin/dermatan sulfate (CS/DS), heparan sulfate/heparin (HS/H) and hyaluronic acid (HA) were evaluated in samples obtained from JIA patients before and after treatment. Electrophoretic analysis of GAGs identified the presence of CS, DS and HS/H in plasma of healthy subjects and JIA patients. CS were the predominant plasma GAGs constituent in all investigated subject. The plasma CS level in untreated patients was significantly decreased. Therapy resulted in an increase in this glycan level. However, plasma CS concentration still remained higher than in controls. Increased levels of DS and HA in untreated JIA patients were recorded. Anti-inflammatory treatment led to normalization of these parameters concentrations. Plasma and urinary concentrations of HS/H were similar in all groups of individuals. Urinary CS/DS and HA were decreased only in untreated patients. CONCLUSIONS: The data presented indicate that changes in plasma and urinary glycosaminoglycan occur in the course of JIA. There are probably the expression of both local articular cartilage matrix and systemic changes in connective tissue remodeling.

[Modifications of chemical composition of blood serum in chronic nitrate intoxication (experimental research)].

Nitrates (salts of nitric acid) are very common substances in nature and are present in almost all living organisms. Relevance of research about features of various pathological processes in chronic nitric intoxication significantly associated with the fact that the intake of nitro compounds has significantly increased in recent years, especially in rural areas where local water sources are used. Investigations were carried out on 20 white Wistar rats. Two series of the experiment ware held: Group I - intact animals (10 animals); Group II - animals after administration of sodium nitrate at a dose of 200 mg/kg in the form of an aqueous solution intragastrically for 60 days (10 animals). Chronic nitrate intoxication leads to a significant increase of the level of serum chondroitin rats with permanent indicators glycoproteins indicates that the products disorganization of proteoglycans from the bone to the blood serum. Increasing of overall level glycosaminoglycans and the third fraction (heparan sulfate), and reducing of the 2-nd fraction (chondroitin-4-sulfate) glycosaminoglycans in serum may be indicative of a chronic lesion of sodium nitrite intoxication general connective tissue (including bone tissues and liver parenchymal).

Genome-scale metabolic modelling of hepatocytes reveals serine deficiency in patients with non-alcoholic fatty liver disease.

Several liver disorders result from perturbations in the metabolism of hepatocytes, and their underlying mechanisms can be outlined through the use of genome-scale metabolic models (GEMs). Here we reconstruct a consensus GEM for hepatocytes, which we call iHepatocytes2322, that extends previous models by including an extensive description of lipid metabolism. We build iHepatocytes2322 using Human Metabolic Reaction 2.0 database and proteomics data in Human Protein Atlas, which experimentally validates the incorporated reactions. The reconstruction process enables improved annotation of the proteomics data using the network centric view of iHepatocytes2322. We then use iHepatocytes2322 to analyse transcriptomics data obtained from patients with non-alcoholic fatty liver disease. We show that blood concentrations of chondroitin and heparan sulphates are suitable for diagnosing non-alcoholic steatohepatitis and for the staging of non-alcoholic fatty liver disease. Furthermore, we observe serine deficiency in patients with NASH and identify PSPH, SHMT1 and BCAT1 as potential therapeutic targets for the treatment of non-alcoholic steatohepatitis.

Use of glucosamine and chondroitin supplements and risk of colorectal cancer.

PURPOSE: Glucosamine and chondroitin are non-vitamin, non-mineral supplements which have anti-inflammatory properties. These supplements are typically used for joint pain and osteoarthritis and are commonly taken as either glucosamine alone or glucosamine plus chondroitin. An exploratory analysis conducted within the VITamins And Lifestyle (VITAL) study observed any use of glucosamine and chondroitin to be associated with reduced risk of colorectal cancer (CRC) after 5 years of follow-up. METHODS: With two additional years of follow-up, we have studied these associations in greater depth, including associations by frequency/duration of use and by formulation, and have evaluated whether observed associations are modified by factors associated with inflammation. Participants include 75,137 western Washington residents aged 50-76 who completed the mailed VITAL questionnaire between 2000 and 2002. Use of glucosamine and chondroitin was ascertained by questions about supplement use during the 10-year period prior to baseline, and participants were followed for CRC through 2008 (n = 557). Cox regression was used to estimate hazard ratios (HRs) and 95 % confidence intervals (CIs). RESULTS: Persons reporting use of glucosamine + chondroitin on 4+ days/week for 3+ years had a non-statistically significant 45 % lower CRC risk than non-users (HR: 0.55; 95 % CI 0.30-1.01; p-trend: 0.16). This association varied by body mass index (p-interaction: 0.006), with inverse association observed among the overweight/obese (p-trend: 0.02), but not among the underweight/normal weight. Use of glucosamine alone was not significantly associated with CRC risk. CONCLUSIONS: There is great need to identify safe and effective cancer preventive strategies, suggesting that glucosamine and chondroitin may merit further attention as a potential chemopreventive agent.

Increased release of matrix components from articular cartilage in experimental canine osteoarthritis.

The release rates of specific components of the proteoglycan aggregates (G1 domain, the chondroitin sulfate and keratan sulfate containing portion of the protein core, and link protein) of the articular cartilage of mature beagles were studied at early stages of canine experimental osteoarthritis (OA), generated by transection of the anterior cruciate ligament. Analysis of cartilage explants and synovial fluids indicates that at early stages of experimental OA, there is increased release of the proteoglycan aggregates of the articular cartilage. This involves a release from the tissue of the components of the proteoglycan that are specifically involved with aggregation together with the glycosaminoglycans of the proteoglycan. These components were detected at elevated levels in the media of explants of cartilage from the operated joint, and in the synovial fluids of the operated joints.

[Glycosaminoglycans in leukocytes in myeloproliferative disorders]. / Glikozaminoglikany leikotsitov pri mieloproliferativnykh zabolevaniiakh.

Content and composition of glycosaminoglycans (GAG) was studied in leukocytes of 30 healthy persons and of patients with different types of myeloproliferative disorders: 32 patients with chronic myeloid leukemia (CML), 10 patients with polycythemia vera (PV), 5 patients with idiopathic myeloid fibrosis (IMF) and 10 patients with acute myelo blast leukemia (AML). The total content of GAG in healthy persons was 97.7 +/- 3.9 micrograms of uronic acid per 100 mg of dry cells, in CML and IMF it was 2-4-fold increased, in PV it was elevated by 20%, in AML it was diminished 3-5-fold. The elevated level of GAG in CML and IMF was due to presence of basophils and considerable quantity of immature cell forms: promyelocytes and myelocytes. In these cells changes in GAGs composition and their properties were shown: an increase of chondroitins deficient in sulfate groups and of heparan sulfate content, especially in basophils. The observed changes in GAG content and composition may be important for biological activity of the leukemic cells.

Effects of acute cartilaginous injury on serum and cartilage lysozyme levels.

Acute cartilage degradation was produced in rabbits by the intravenous injection of crude papain. This resulted in a significant rise in serum lysozyme in 97% of the animals, as well as a fall in the residual lysozyme content of auricular and costal cartilage. The rise in serum lysozyme paralleled the rise in serum chondroitin sulfate. The source of the rise in lysozyme appeared to be the release of extracellular, nonlysosomal lysozyme from the cartilage matrix. Serum lysozyme elevation in arthritic disorders may reflect cartilage degradation.

Mucopolysaccharides in peripheral leucocytes of cancer patients.

The presence of mucopolysaccharides (MPS) in leucocytes of peripheral blood of 19 cancer patients, 13 patients with pulmonary tuberculosis and 14 normal controls, was studied histochemically. MPS was revealed in different proportions in polynuclears and mononuclears. According to the staining technics, the MPS appear to be mainly carboxylated and contain hyaluronic acid and chondroitinsulphate groups.The quantitative analysis revealed that MPS appeared only in around 3% of leucocytes of normal controls, while in the cancer patients 56% of polynuclear and 90% of mononuclears contained it. In the tuberculous patients, 90% of polynuclears and 86% of the mononuclears revealed MPS. The differences between the prevalence of leucocytes containing MPS in controls and in cancer or tuberculous patients are highly significant.The possibility that the difference in MPS content of leucocytes is related with low inmunological activity is postulated.

Mucopolysaccharide in the blood of a patient with neuroblastoma.

In a case of neuroblastoma the presence of an abnormal blood constituent was suspected from the raised erythrocyte sedimentation rate, sludging of the red cells, marked rouleaux formation, an atypical Leishman stain, increased plasma viscosity, and a distorted protein electrophoresis pattern. The abnormal constituent was shown to be a mucopolysaccharide which was either hyaluronic acid or chondroitin sulphate.