In the recessive aminoaciduria Lysinuric Protein Intolerance (LPI), mutations of SLC7A7/y+LAT1 impair system y+L transport activity for cationic amino acids. A severe complication of LPI is a form of Pulmonary Alveolar Proteinosis (PAP), in which alveolar spaces are filled with lipoproteinaceous material because of the impaired surfactant clearance by resident macrophages. The pathogenesis of LPI-associated PAP remains still obscure. The present study investigates for the first time the expression and function of y+LAT1 in monocytes and macrophages isolated from a patient affected by LPI-associated PAP. A comparison with mesenchymal cells from the same subject has been also performed. METHODS: Monocytes from peripheral blood were isolated from a 21-year-old patient with LPI. Alveolar macrophages and fibroblastic-like mesenchymal cells were obtained from a whole lung lavage (WLL) performed on the same patient. System y+L activity was determined measuring the 1-min uptake of [3H]-arginine under discriminating conditions. Gene expression was evaluated through qRT-PCR. RESULTS: We have found that: 1) system y+L activity is markedly lowered in monocytes and alveolar macrophages from the LPI patient, because of the prevailing expression of SLC7A7/y+LAT1 in these cells; 2) on the contrary, fibroblasts isolated from the same patient do not display the transport defect due to compensation by the SLC7A6/y+LAT2 isoform; 3) in both normal and LPI monocytes, GM-CSF induces the expression of SLC7A7, suggesting that the gene is a target of the cytokine; 4) GM-CSF-induced differentiation of LPI monocytes is comparable to that of normal cells, demonstrating that GM-CSF signalling is unaltered; 5) general and respiratory conditions of the patient, along with PAP-associated parameters, markedly improved after GM-CSF therapy through aerosolization. CONCLUSIONS: Monocytes and macrophages, but not fibroblasts, derived from a LPI patient clearly display the defect in system y+L-mediated arginine transport. The different transport phenotypes are referable to the relative levels of expression of SLC7A7 and SLC7A6. Moreover, the expression of SLC7A7 is regulated by GM-CSF in monocytes, pointing to a role of y+LAT1 in the pathogenesis of LPI associated PAP.

In Lysinuric Protein Intolerance system y+Lactivity is defective in monocytes and inGM-CSF-differentiated macrophages / Barilli, Amelia; Rotoli, Bianca Maria; Visigalli, Rossana; Bussolati, Ovidio; Gazzola, Giancarlo; Z., Kadija; G., Rodi; F., Mariani; M. L., Ruzza; M., Luisetti; Dall'Asta, Valeria. - In: ORPHANET JOURNAL OF RARE DISEASES. - ISSN 1750-1172. - 5:(2010), pp. 32-42. [10.1186/1750-1172-5-32]

In Lysinuric Protein Intolerance system y+Lactivity is defective in monocytes and inGM-CSF-differentiated macrophages

BARILLI, Amelia;ROTOLI, Bianca Maria;VISIGALLI, Rossana;BUSSOLATI, Ovidio;GAZZOLA, Giancarlo;DALL'ASTA, Valeria
2010-01-01

Abstract

In the recessive aminoaciduria Lysinuric Protein Intolerance (LPI), mutations of SLC7A7/y+LAT1 impair system y+L transport activity for cationic amino acids. A severe complication of LPI is a form of Pulmonary Alveolar Proteinosis (PAP), in which alveolar spaces are filled with lipoproteinaceous material because of the impaired surfactant clearance by resident macrophages. The pathogenesis of LPI-associated PAP remains still obscure. The present study investigates for the first time the expression and function of y+LAT1 in monocytes and macrophages isolated from a patient affected by LPI-associated PAP. A comparison with mesenchymal cells from the same subject has been also performed. METHODS: Monocytes from peripheral blood were isolated from a 21-year-old patient with LPI. Alveolar macrophages and fibroblastic-like mesenchymal cells were obtained from a whole lung lavage (WLL) performed on the same patient. System y+L activity was determined measuring the 1-min uptake of [3H]-arginine under discriminating conditions. Gene expression was evaluated through qRT-PCR. RESULTS: We have found that: 1) system y+L activity is markedly lowered in monocytes and alveolar macrophages from the LPI patient, because of the prevailing expression of SLC7A7/y+LAT1 in these cells; 2) on the contrary, fibroblasts isolated from the same patient do not display the transport defect due to compensation by the SLC7A6/y+LAT2 isoform; 3) in both normal and LPI monocytes, GM-CSF induces the expression of SLC7A7, suggesting that the gene is a target of the cytokine; 4) GM-CSF-induced differentiation of LPI monocytes is comparable to that of normal cells, demonstrating that GM-CSF signalling is unaltered; 5) general and respiratory conditions of the patient, along with PAP-associated parameters, markedly improved after GM-CSF therapy through aerosolization. CONCLUSIONS: Monocytes and macrophages, but not fibroblasts, derived from a LPI patient clearly display the defect in system y+L-mediated arginine transport. The different transport phenotypes are referable to the relative levels of expression of SLC7A7 and SLC7A6. Moreover, the expression of SLC7A7 is regulated by GM-CSF in monocytes, pointing to a role of y+LAT1 in the pathogenesis of LPI associated PAP.
2010
In Lysinuric Protein Intolerance system y+Lactivity is defective in monocytes and inGM-CSF-differentiated macrophages / Barilli, Amelia; Rotoli, Bianca Maria; Visigalli, Rossana; Bussolati, Ovidio; Gazzola, Giancarlo; Z., Kadija; G., Rodi; F., Mariani; M. L., Ruzza; M., Luisetti; Dall'Asta, Valeria. - In: ORPHANET JOURNAL OF RARE DISEASES. - ISSN 1750-1172. - 5:(2010), pp. 32-42. [10.1186/1750-1172-5-32]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11381/2336368
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