Luca Vedovelli

Bio: Luca Vedovelli is an academic researcher from University of Padua. The author has contributed to research in topics: Medicine & Lung. The author has an hindex of 12, co-authored 52 publications receiving 361 citations. Previous affiliations of Luca Vedovelli include Harvard University.

Aldosterone stimulates vacuolar H(+)-ATPase activity in renal acid-secretory intercalated cells mainly via a protein kinase C-dependent pathway.

Abstract: Urinary acidification in the collecting duct is mediated by the activity of H(+)-ATPases and is stimulated by various factors including angiotensin II and aldosterone. Classically, aldosterone effects are mediated via the mineralocorticoid receptor. Recently, we demonstrated a nongenomic stimulatory effect of aldosterone on H(+)-ATPase activity in acid-secretory intercalated cells of isolated mouse outer medullary collecting ducts (OMCD). Here we investigated the intracellular signaling cascade mediating this stimulatory effect. Aldosterone stimulated H(+)-ATPase activity in isolated mouse and human OMCDs. This effect was blocked by suramin, a general G protein inhibitor, and GP-2A, a specific G(αq) inhibitor, whereas pertussis toxin was without effect. Inhibition of phospholipase C with U-73122, chelation of intracellular Ca(2+) with BAPTA, and blockade of protein kinase C prevented the stimulation of H(+)-ATPases. Stimulation of PKC by DOG mimicked the effect of aldosterone on H(+)-ATPase activity. Similarly, aldosterone and DOG induced a rapid translocation of H(+)-ATPases to the luminal side of OMCD cells in vivo. In addition, PD098059, an inhibitor of ERK1/2 activation, blocked the aldosterone and DOG effects. Inhibition of PKA with H89 or KT2750 prevented and incubation with 8-bromoadenosine-cAMP mildly increased H(+)-ATPase activity. Thus, the nongenomic modulation of H(+)-ATPase activity in OMCD-intercalated cells by aldosterone involves several intracellular pathways and may be mediated by a G(αq) protein-coupled receptor and PKC. PKA and cAMP appear to have a modulatory effect. The rapid nongenomic action of aldosterone may participate in the regulation of H(+)-ATPase activity and contribute to final urinary acidification.

Effects of amniotic membrane extract on primary human corneal epithelial and limbal cells

Abstract: Background To assess the effects of amniotic membrane extract (AMX) on cellular activity of primary human corneal epithelial (HCE) cells under mechanical and oxidative stress, and on human limbal cells under oxidative stress. Methods Corneal mechanical stress was simulated with a linear scratch in confluent HCE cell plates, then incubated with 0.1% AMX for 48 and 72 h. Subjecting HCE cultures to 0.5 mmol/L tertiary-butylhydroperoxide for 1 h simulated an oxidative stress. 0.1% AMX-treated cultures were compared with controls at 24 and 48 h using cellular viability assay, along with 12-h AMX pretreatment and human limbal cell comparisons. Results Mechanical stress on HCE cultures revealed a statistically significant distance ratio at 48 and 72 h in favour of 0.1% AMX-treated cultures (P = 0.021 and 0.035, respectively). Oxidative stress did not reveal any significant difference in cellular viability of AMX-treated versus control cultures. Twelve hour AMX pre-treatment prior to oxidative stress revealed a significant difference after 24 h from oxidative injury (73.3% AMX vs. 66.0% control, P = 0.035), but not after 48 h. Human limbal cells demonstrated significantly improved oxidative viability compared with HCE cells, with (91.0% vs. 82.0% control, P = 0.017) and without 0.1% AMX pre-treatment (91.2% vs. 83.7% control, P = 0.019). Conclusions HCE cells treated with AMX healed faster after mechanical insult, suggesting a potential benefit in acute corneal injuries. Under oxidative stress, human limbal cells, a more proliferative cell type, showed superior viability compared with HCE cells.

Altered V-ATPase expression in renal intercalated cells isolated from B1 subunit-deficient mice by fluorescence-activated cell sorting.

Abstract: Unlike human patients with mutations in the 56-kDa B1 subunit isoform of the vacuolar proton-pumping ATPase (V-ATPase), B1-deficient mice (Atp6v1b1−/−) do not develop metabolic acidosis under basel...

A Comprehensive Comparison of Bovine and Porcine Decellularized Pericardia: New Insights for Surgical Applications.

Abstract: Xenogeneic pericardium-based substitutes are employed for several surgical indications after chemical shielding, limiting their biocompatibility and therapeutic durability. Adverse responses to these replacements might be prevented by tissue decellularization, ideally removing cells and preserving the original extracellular matrix (ECM). The aim of this study was to compare the mostly applied pericardia in clinics, i.e., bovine and porcine tissues, after their decellularization, and obtain new insights for their possible surgical use. Bovine and porcine pericardia were submitted to TRICOL decellularization, based on osmotic shock, detergents and nuclease treatment. TRICOL procedure resulted in being effective in cell removal and preservation of ECM architecture of both species’ scaffolds. Collagen and elastin were retained but glycosaminoglycans were reduced, significantly for bovine scaffolds. Tissue hydration was varied by decellularization, with a rise for bovine pericardia and a decrease for porcine ones. TRICOL significantly increased porcine pericardial thickness, while a non-significant reduction was observed for the bovine counterpart. The protein secondary structure and thermal denaturation profile of both species’ scaffolds were unaltered. Both pericardial tissues showed augmented biomechanical compliance after decellularization. The ECM bioactivity of bovine and porcine pericardia was unaffected by decellularization, sustaining viability and proliferation of human mesenchymal stem cells and endothelial cells. In conclusion, decellularized bovine and porcine pericardia demonstrate possessing the characteristics that are suitable for the creation of novel scaffolds for reconstruction or replacement: differences in water content, thickness and glycosaminoglycans might influence some of their biomechanical properties and, hence, their indication for surgical use.

Influence of Diet On the Distribtion of Nitrogen Isotopes in Animals

Abstract: The influence of diet on the distribution of nitrogen isotopes in animals was investigated by analyzing animals grown in the laboratory on diets of constant nitrogen isotopic composition. The isotopic composition of the nitrogen in an animal reflects the nitrogen isotopic composition of its diet. The δ^(15)N values of the whole bodies of animals are usually more positive than those of their diets. Different individuals of a species raised on the same diet can have significantly different δ^(15)N values. The variability of the relationship between the δ^(15)N values of animals and their diets is greater for different species raised on the same diet than for the same species raised on different diets. Different tissues of mice are also enriched in ^(15)N relative to the diet, with the difference between the δ^(15)N values of a tissue and the diet depending on both the kind of tissue and the diet involved. The δ^(15)N values of collagen and chitin, biochemical components that are often preserved in fossil animal remains, are also related to the δ^(15)N value of the diet. The dependence of the δ^(15)N values of whole animals and their tissues and biochemical components on the δ^(15)N value of diet indicates that the isotopic composition of animal nitrogen can be used to obtain information about an animal's diet if its potential food sources had different δ^(15)N values. The nitrogen isotopic method of dietary analysis probably can be used to estimate the relative use of legumes vs non-legumes or of aquatic vs terrestrial organisms as food sources for extant and fossil animals. However, the method probably will not be applicable in those modern ecosystems in which the use of chemical fertilizers has influenced the distribution of nitrogen isotopes in food sources. The isotopic method of dietary analysis was used to reconstruct changes in the diet of the human population that occupied the Tehuacan Valley of Mexico over a 7000 yr span. Variations in the δ^(15)C and δ^(15)N values of bone collagen suggest that C_4 and/or CAM plants (presumably mostly corn) and legumes (presumably mostly beans) were introduced into the diet much earlier than suggested by conventional archaeological analysis.

V‐ATPase Interacts with ARNO and Arf6 in Early Endosomes and Regulates the Protein Degradative Pathway

Abstract: The recruitment of the small GTPase Arf6 and ARNO from cytosol to endosomal membranes is driven by V-ATPase-dependent intra-endosomal acidification. The molecular mechanism that mediates this pH-sensitive recruitment and its role are unknown. Here, we demonstrate that Arf6 interacts with the c-subunit, and ARNO with the a2-isoform of V-ATPase. The a2-isoform is targeted to early endosomes, interacts with ARNO in an intra-endosomal acidification-dependent manner, and disruption of this interaction results in reversible inhibition of endocytosis. Inhibition of endosomal acidification abrogates protein trafficking between early and late endosomal compartments. These data demonstrate the crucial role of early endosomal acidification and V-ATPase/ARNO/Arf6 interactions in the regulation of the endocytic degradative pathway. They also indicate that V-ATPase could modulate membrane trafficking by recruiting and interacting with ARNO and Arf6; characteristics that are consistent with the role of V-ATPase as an essential component of the endosomal pH-sensing machinery.

Deuterium- and Tritium-Labelled Compounds: Applications in the Life Sciences

Abstract: Hydrogen isotopes are unique tools for identifying and understanding biological and chemical processes. Hydrogen isotope labelling allows for the traceless and direct incorporation of an additional mass or radioactive tag into an organic molecule with almost no changes in its chemical structure, physical properties, or biological activity. Using deuterium-labelled isotopologues to study the unique mass-spectrometric patterns generated from mixtures of biologically relevant molecules drastically simplifies analysis. Such methods are now providing unprecedented levels of insight in a wide and continuously growing range of applications in the life sciences and beyond. Tritium (3 H), in particular, has seen an increase in utilization, especially in pharmaceutical drug discovery. The efforts and costs associated with the synthesis of labelled compounds are more than compensated for by the enhanced molecular sensitivity during analysis and the high reliability of the data obtained. In this Review, advances in the application of hydrogen isotopes in the life sciences are described.

Altered surfactant function andstructure inSP-Agene targeted mice

Abstract: Thesurfactant protein A (SP-A) genewas disrupted byhomologous recombination inembryonic stem cells thatwereusedtogenerate homozygous SP-A-deficient mice. SP-AmRNAandprotein werenotdetectable inthelungs ofSP-A(-/-) mice, andperinatal survival ofSP-A(-/-) micewasnotaltered compared withwild-type mice. Lung morphology, surfactant proteins B-D,lungtissue, alveolar phospholipid pool sizes andcomposition, andlungcompliance inSP-A(-/-) micewereunaltered. Atthehighest concen- tration tested, surfactant fromSP-A(-/-) miceproduced the samesurface tension as(+/+)mice. Atlower concentrations, minimumsurface tensions werehigher forSP-A(-/-) mice. Attheultrastructural level, typeIIcell morphology wasthe sameinSP-A(+/+) and(-/-) mice. Whilealveolar phos- pholipid poolsizes wereunperturbed, tubular myelin figures weredecreased inthelungsofSP-A(-/-) mice.A null mutation ofthemurine SP-Ageneinterferes withtheforma- tionoftubular myelin without detectably altering postnatal survival orpulmonary function. Surfactant protein A (SP-A) isanabundant, phospholipid- associated protein inpulmonary surfactant. MurineSP-Ais encoded byasingle genelocated onchromosome 14,atasite syntenic withtheSP-Alocus onchromosome 10inhumans(1). SP-Aissynthesized andsecreted primarily bytypeIIand bronchiolar cells intherespiratory epithelium. Inthealveolus, SP-Aformslarge oligomers andisclosely associated with tubular myelin, themajor extracellular formofsurfactant (for areview, seeref. 2).SP-Acontains a10-kDa collagen-like amino-terminal domainandaglobular carboxyl-terminal do- mainwithstructural homology toSP-D,mannosebinding protein, Clq,andother membersofthecollectin family of mammalian lectins (3). Various functions related tosurfactant havebeenascribed toSP-A,basedprimarily oninvitro findings, whichinclude enhancing phospholipid uptake (4), inhibiting surfactant secretion byisolated typeIIepithelial cells (5,6),contributing totubular myelin formation (7), enhancing surfactant spreading, stabilizing phospholipid mix- tures (8)andconferring resistance toprotein mediated inac- tivation ofsurfactant (9). Evidence hasalso accumulated that supports aroleforSP-Ainhostdefense. SP-Abinds and increases theuptake ofavariety ofbacterial andviral patho- gensbyalveolar macrophages, activates alveolar macrophage metabolism, andenhances theuptake ofbacterial pathogens bybothmacrophages andmonocytes invitro (10-13). Inspite oftheextensive invitro evidence thatSP-Aisinvolved in surfactant homeostasis andfunction, thereislittle direct evidence that SP-Aplays acritical role insurfactant function invivo. Totest therole ofSP-Ainvivo, themouseSP-Agene