Renal function can be impaired in children with primary hyperoxaluria type 3.

BACKGROUND: Primary hyperoxaluria type 3 (PH3) is characterized by mutations in the 4-hydroxy-2-oxoglutarate aldolase (HOGA1) gene. PH3 patients are believed to present with a less severe phenotype than those with PH1 and PH2, but the clinical characteristics of PH3 patients have yet to be defined in sufficient detail. The aim of this study was to report our experience with PH3. METHODS: Genetic analysis of HOGA1 was performed in patients with a high clinical suspicion of PH after the presence of mutations in the alanine-glyoxylate aminotransferase gene had been ruled out. Clinical, biochemical and genetic data of the seven patients identified with HOGA1 mutations were subsequently retrospectively reviewed. RESULTS: Among the seven patients identified with HOGA1 mutations the median onset of clinical symptoms was 1.8 (range 0.4-9.8) years. Five patients initially presented with urolithiasis, and two other patients presented with urinary tract infection. All patients experienced persistent hyperoxaluria. Seven mutations were found in HOGA1, including two previously unreported ones, c.834 + 1G > T and c.3G > A. At last follow-up, two patients had impaired renal function based on estimated glomerular filtration rates (GFRs) of 77 and 83 mL/min per 1.73 m(2), respectively. CONCLUSIONS: We found that the GFR was significantly impaired in two of our seven patients with PH3 diagnosed during childhood. This finding is in contrast to the early-impaired renal function in PH1 and PH2 and appears to refute to preliminary reassuring data on renal function in PH3.

Oficines Heineken

Award-winning

Sorcin links pancreatic β cell lipotoxicity to ER Ca2+ stores.

NlmCategory="UNASSIGNED">Preserving β cell function during the development of obesity and insulin resistance would limit the worldwide epidemic of type 2 diabetes (T2DM). Endoplasmic reticulum (ER) calcium (Ca(2+)) depletion induced by saturated free fatty acids and cytokines causes β cell ER stress and apoptosis, but the molecular mechanisms behind these phenomena are still poorly understood. Here, we demonstrate that palmitate-induced sorcin (SRI) down-regulation, and subsequent increases in glucose-6-phosphatase catalytic subunit-2 (G6PC2) levels contribute to lipotoxicity. SRI is a calcium sensor protein involved in maintaining ER Ca(2+) by inhibiting ryanodine receptor activity and playing a role in terminating Ca(2+)-induced Ca(2+) release. G6PC2, a GWAS gene associated with fasting blood glucose, is a negative regulator of glucose-stimulated insulin secretion (GSIS). High fat feeding in mice and chronic exposure of human islets to palmitate decreases endogenous SRI expression while levels of G6PC2 mRNA increase. Sorcin null mice are glucose intolerant, with markedly impaired GSIS and increased expression of G6pc2. Under high fat diet, mice overexpressing SRI in the β cell display improved glucose tolerance, fasting blood glucose and GSIS, whereas G6PC2 levels are decreased and cytosolic and ER Ca(2+) are increased in transgenic islets. SRI may thus provide a target for intervention in T2DM.

De concoctione ventriculi

Invocatio: Sanctissimi Jehovae ductu! - Esipuhe.

Secretion of Streptomyces tendae antifungal protein 1 by Lactococcus lactis

Lactococcus lactis, the model lactic acid bacterium, is a good candidate for heterologous protein production in both foodstuffs and the digestive tract. We attempted to produce Streptomyces tendae antifungal protein 1 (Afp1) in L. lactis with the objective of constructing a strain able to limit fungal growth. Since Afp1 activity requires disulfide bond (DSB) formation and since intracellular redox conditions are reportedly unfavorable for DSB formation in prokaryotes, Afp1 was produced as a secreted form. An inducible expression-secretion system was used to drive Afp1 secretion by L. lactis; Afp1 was fused or not with LEISSTCDA, a synthetic propeptide (LEISS) that has been described to be a secretion enhancer. Production of Afp1 alone was not achieved, but production of LEISS-Afp1 was confirmed by Western blot and immunodetection with anti-Afp1 antibodies. This protein (molecular mass: 9.8 kDa) is the smallest non-bacteriocin heterologous protein ever reported to be secreted in L. lactis via the Sec-dependent pathway. However, no anti-fungal activity was detected, even in concentrated samples of induced supernatant. This could be due to a too low secretion yield of Afp1 in L. lactis, to the absence of DSB formation, or to an improper DSB formation involving the additional cysteine residue included in LEISS propeptide. This raises questions about size limits, conformation problems, and protein secretion yields in L. lactis.