Transgenic Overexpression of LARGE Induces α-Dystroglycan Hyperglycosylation in Skeletal and Cardiac Muscle

BACKGROUND: LARGE is one of seven putative or demonstrated glycosyltransferase enzymes defective in a common group of muscular dystrophies with reduced glycosylation of α-dystroglycan. Overexpression of LARGE induces hyperglycosylation of α-dystroglycan in both wild type and in cells from dystroglycanopathy patients, irrespective of their primary gene defect, restoring functional glycosylation. Viral delivery of LARGE to skeletal muscle in animal models of dystroglycanopathy has identical effects in vivo, suggesting that the restoration of functional glycosylation could have therapeutic applications in these disorders. Pharmacological strategies to upregulate Large expression are also being explored. METHODOLOGY/PRINCIPAL FINDINGS: In order to asses the safety and efficacy of long term LARGE over-expression in vivo, we have generated four mouse lines expressing a human LARGE transgene. On observation, LARGE transgenic mice were indistinguishable from the wild type littermates. Tissue analysis from young mice of all four lines showed a variable pattern of transgene expression: highest in skeletal and cardiac muscles, and lower in brain, kidney and liver. Transgene expression in striated muscles correlated with α-dystroglycan hyperglycosylation, as determined by immunoreactivity to antibody IIH6 and increased laminin binding on an overlay assay. Other components of the dystroglycan complex and extracellular matrix ligands were normally expressed, and general muscle histology was indistinguishable from wild type controls. Further detailed muscle physiological analysis demonstrated a loss of force in response to eccentric exercise in the older, but not in the younger mice, suggesting this deficit developed over time. However this remained a subclinical feature as no pathology was observed in older mice in any muscles including the diaphragm, which is sensitive to mechanical load-induced damage. CONCLUSIONS/SIGNIFICANCE: This work shows that potential therapies in the dystroglycanopathies based on LARGE upregulation and α-dystroglycan hyperglycosylation in muscle should be safe

Congenital Anomalies of the Kidney and the Urinary Tract (CAKUT)

This article reviews the majority of Congenital Anomalies of the Kidney and Urinary Tract (CAKUT) with emphasis in Pediatric Pathology describing and illustrating lesions as varied as ureteral duplications, ureteropelvic junction obstruction, horseshoe kidney, posterior urethral valve and prune belly syndrome, obstructive renal dysplasia, nonmotile ciliopathies and several syndromes associated with renal malformations (Meckel–Joubert, short rib, Bardet–Biedl, asplenia/polysplenia, hereditary renal adysplasia, Zellweger, trisomies, VACTER-L, Potter, caudal dysplasia, and sirenomelia), as well as ADPK, and ARPK. The purpose of this review is not only to describe the congenital renal anomalies, but also to analyze the more recent therapeutic interventions that may modify the natural history of some of these severe conditions

Biogeochemical cycling of sulphur in karst and transfer into speleothem archives at Grotta di Ernesto, Italy

Trace amounts of sulphur in speleothems suggest that stalagmites may act as archives of sulphur deposition, thereby recording aspects of atmospheric variability in sulphur content. Accurate interpretation of this novel sulphur archive depends upon understanding how biogeochemical cycling in the soil and epikarst above the cave may modify the precursor atmospheric values of sulphur concentration and isotopic composition prior to incorporation into the speleothem record. Dual isotope analysis of δ34S-SO4 and δ18O-SO4 is used to trace biogeochemical transformations of atmospheric sulphur through the cave system at Grotta di Ernesto in the Italian Alps and builds towards a framework for interpretation of speleothem sulphur archives which depends on overlying ecosystem dynamics and karst hydrological properties. A three component model of atmospheric signal modification is proposed to be driven by 1. vegetation and soil cycling, 2. the degree of groundwater mixing in the karst aquifer; and 3. redox status. The relative influence of each process is specific to individual drip flow sites and associated stalagmites, rendering each suphur archive a unique signal of environmental conditions. Under conditions found in the soil and epikarst above Grotta di Ernesto, the dual isotope signatures of sulphate sulphur and oxygen incorporated into speleothem carbonate, closely reflect past conditions of industrial sulphur loading to the atmosphere and the extent of signal modification through biogeochemical cycling and aquifer mixing