Disentangling molecular and clinical stratification patterns in beta-galactosidase deficiency.

INTRODUCTION: This study aims to define the phenotypic and molecular spectrum of the two clinical forms of ß-galactosidase (ß-GAL) deficiency, GM1-gangliosidosis and mucopolysaccharidosis IVB (Morquio disease type B, MPSIVB). METHODS: Clinical and genetic data of 52 probands, 47 patients with GM1-gangliosidosis and 5 patients with MPSIVB were analysed. RESULTS: The clinical presentations in patients with GM1-gangliosidosis are consistent with a phenotypic continuum ranging from a severe antenatal form with hydrops fetalis to an adult form with an extrapyramidal syndrome. Molecular studies evidenced 47 variants located throughout the sequence of the GLB1 gene, in all exons except 7, 11 and 12. Eighteen novel variants (15 substitutions and 3 deletions) were identified. Several variants were linked specifically to early-onset GM1-gangliosidosis, late-onset GM1-gangliosidosis or MPSIVB phenotypes. This integrative molecular and clinical stratification suggests a variant-driven patient assignment to a given clinical and severity group. CONCLUSION: This study reports one of the largest series of b-GAL deficiency with an integrative patient stratification combining molecular and clinical features. This work contributes to expand the community knowledge regarding the molecular and clinical landscapes of b-GAL deficiency for a better patient management.

A thermolabile aldolase A mutant causes fever-induced recurrent rhabdomyolysis without hemolytic anemia.

Aldolase A deficiency has been reported as a rare cause of hemolytic anemia occasionally associated with myopathy. We identified a deleterious homozygous mutation in the ALDOA gene in 3 siblings with episodic rhabdomyolysis without hemolytic anemia. Myoglobinuria was always triggered by febrile illnesses. We show that the underlying mechanism involves an exacerbation of aldolase A deficiency at high temperatures that affected myoblasts but not erythrocytes. The aldolase A deficiency was rescued by arginine supplementation in vitro but not by glycerol, betaine or benzylhydantoin, three other known chaperones, suggesting that arginine-mediated rescue operated by a mechanism other than protein chaperoning. Lipid droplets accumulated in patient myoblasts relative to control and this was increased by cytokines, and reduced by dexamethasone. Our results expand the clinical spectrum of aldolase A deficiency to isolated temperature-dependent rhabdomyolysis, and suggest that thermolability may be tissue specific. We also propose a treatment for this severe disease.

Large-scale screening of lipase acid deficiency in at risk population.

BACKGROUND: Lysosomal acid lipase deficiency (LALD, OMIM#278000) is a rare lysosomal disorder with an autosomal recessive inheritance. The main clinical manifestations are related to a progressive accumulation of cholesteryl esters, triglycerides or both within the lysosome in different organs such as the liver, spleen, and cardiovascular system. A wide range of clinical severity is associated with LALD including a severe very rare antenatal/neonatal/infantile phenotype named Wolman disease and a late-onset form named cholesteryl ester storage disease (CESD). METHODS: This study aimed to investigate a cohort of at-risk patients (4174) presenting with clinical or biological signs consistent with LALD using the assessment of LAL activity on dried blood spots. RESULTS: LAL activity was lower than 0.05 nmol/punch/L (cut-off: 0.12) in 19 patients including 13 CESD and 6 Wolman. Molecular study has been conducted in 17 patients and succeeded in identifying 34 mutated alleles. Fourteen unique variants have been characterized, 7 of which are novel. CONCLUSION: This study allowed to identify a series of patients and expanded the molecular spectrum knowledge of LALD. Besides, a new screening criteria grid based on the clinical/biological data from our study and the literature has been proposed in order to enhance the diagnosis rate in at risk populations.

Early Prediction of Graft Outcomes After Kidney Transplantation From Donors After Circulatory Death: Biomarkers and Transplantation Characteristics.

BACKGROUND: This study aimed to identify transplantation characteristics and biomarkers that predict outcomes for kidney transplant (KT) patients from donors after circulatory death (DCDs). METHODS: Consecutive patients receiving a KT from a DCD in our center between 2014 and 2016 were included; the reference population was recipients with a living donor KT. The urinary tubular injury biomarker-to-creatinine ratio and serum lactate dehydrogenase (LDH) were measured at post-transplant days 1 and 3. The primary outcome was the occurrence of delayed graft function (DGF). Descriptive and receiver operating characteristic analyses were performed. RESULTS: Forty-one patients were included in the analysis: 15 (36.59%) DCD KTs (9 of which suffered from DGF) and 26 (63.41%) living donor KTs. For the primary endpoint, neutrophil gelatinase-associated lipocalin, N-acetyl-beta-D-glucosaminidase, urinary tubular injury biomarker-to-creatinine ratio, and LDH areas under the curve were 1 and 0.96 (95% confidence interval: 0.84-1.0), 1 and 0.92 (95% confidence interval: 0.73-1.0), respectively. Among the transplant characteristics, only the 30-minute resistive index on the perfusion machine was significantly higher in DCD KTs with DGF vs those without DGF (0.26 mm Hg/mL/min [0.20; 0.32] vs 0.14 mm Hg/mL/min [0.12; 0.16], P = .05). Median 3-month creatinine clearance among DGF DCD KTs was 49 mL/min/1.73 m2 [IQR: 42; 65] and 65 mL/min/1.73 m2 [IQR: 62; 66] among DCD KTs without DGF (P = .22). CONCLUSION: In the DCD KT population, clinical and biological markers were identified that provided predictive tools for DGF. Thus, systematic measurement of these biomarkers, particularly LDH, could improve the management of kidney graft recipients' immunosuppressive therapy.

Involvement of cysteinyl leukotrienes in angiotensin II-induced contraction in isolated aortas from transgenic (mRen-2)27 rats.

OBJECTIVES: We have previously reported that 5-lipoxygenase-derived products, and particularly the cysteinyl leukotrienes (CysLTs), were involved in angiotensin II (Ang II)-induced contractions in isolated aortas from spontaneously hypertensive rats. DESIGN: The aim of this study was to assess the role of CysLTs in the vascular response to Ang II in an Ang II-dependent model of hypertension, the (mRen-2)27 transgenic rats (TGs). METHODS: Intact aortic rings from TG and normotensive Sprague-Dawley rats (SDs) were suspended in organ chambers for isometric tension development in response to Ang II. In addition, the release of CysLTs in response to Ang II (0.3 micromol/l) was measured by enzyme immunoassay. RESULTS: In isolated aortas from TG rats, pretreatment with the 5-lipoxygenase inhibitor (AA861, 10 micromol/l) or the CysLT1 receptor antagonist (MK571, 1 micromol/l) significantly (P < 0.05) reduced Ang II-induced contractions by 52 and 42%, respectively. In addition, Ang II induced a 2.6-fold increase in CysLT release (pg/mg dry weight tissue: 58.3 +/- 17.9 (Ang II, n = 7) versus 22.5 +/- 5.9 (basal, n = 7) P < 0.05), which was inhibited by the AT1 receptor antagonist losartan (1 micromol/l). In contrast, in aortas from SD rats, pretreatment with AA861 or MK571 did not alter Ang II-induced contraction and CysLT production remained unchanged after exposure to Ang II. CONCLUSION: These data suggest that CysLTs are involved in the contractile responses to Ang II in isolated aortas from TG but not from SD rats.

Cellular and molecular mechanisms activating the cell death processes by chalcones: Critical structural effects.

Chalcones are naturally occurring compounds with diverse pharmacological activities. Chalcones derive from the common structure: 1,3-diphenylpropenone. The present study aims to better understand the mechanistic pathways triggering chalcones anticancer effects and providing evidences that minor structural difference could lead to important difference in mechanistic effect. We selected two recently investigated chalcones (A and B) and investigated them on glioblastoma cell lines. It was found that chalcone A induced an apoptotic process (type I PCD), via the activation of caspase-3, -8 and -9. Chalcone A also increased CDK1/cyclin B ratios and decreased the mitochondrial transmembrane potential (ΔΨm). Chalcone B induced an autophagic cell death process (type II PCD), ROS-related but independent of both caspases and protein synthesis. Both chalcones increased Bax/Bcl2 ratios and decreased Ki67 and CD71 antigen expressions. The present investigation reveals that despite the close structure of chalcones A and B, significant differences in mechanism of effect were found.

Changing the conformation state of cytochrome b558 initiates NADPH oxidase activation: MRP8/MRP14 regulation.

Phagocyte NADPH oxidase generates O2. for defense mechanisms and cellular signaling. Myeloid-related proteins MRP8 and MRP14 of the S100 family are EF-hand calcium-binding proteins. MRP8 and MRP14 were co-isolated from neutrophils on an anti-p47phox matrix with oxidase cytosolic factors and identified by mass spectrometry. MRP8 and MRP14 are absent from Epstein-Barr virus-immortalized B lymphocytes, and, coincidentally, these cells display weak oxidase activity compared with neutrophils. MRP8/MRP14 that was purified from neutrophils enhanced oxidase turnover of B cells in vitro, suggesting that MRP8/MRP14 is involved in the activation process. This was confirmed ex vivo by co-transfection of Epstein-Barr virus-transformed B lymphocytes with genes encoding MRP8 and MRP14. In a semi-recombinant cell-free assay, recombinant MRP8/MRP14 increased the affinity of p67phox for cytochrome b558 synergistically with p47phox. Moreover, MRP8/MRP14 initiated oxidase activation on its own, through a calcium-dependent specific interaction with cytochrome b558 as shown by atomic force microscopy and a structure-function relationship investigation. The data suggest that the change of conformation in cytochrome b558, which initiates the electron transfer, can be mediated by effectors other than oxidase cytosolic factors p67phox and p47phox. Moreover, MRP8/MRP14 dimer behaves as a positive mediator of phagocyte NADPH oxidase regulation.