BACKGROUND: Nephropathic cystinosis is a lysosomal storage disease that is caused by mutations in the CTNS gene encoding a cystine/proton symporter cystinosin and an isoform cystinosin-LKG which is generated by an alternative splicing of exon 12. We have investigated the physiological role of the cystinosin-LKG that is widely expressed in epithelial tissues. METHODS: We have analyzed the intracellular localization and the function of the cystinosin-LKG conjugated with DsRed (cystinosin-LKG-RFP) in Madin-Darby canine kidney cells (MDCK II) and in proximal tubular epithelial cells carrying a deletion of the CTNS gene (cystinotic PTEC), respectively. RESULTS: Cystinosin-LKG-RFP colocalized with markers of lysosomes, late endosomes and was also expressed on the apical surface of polarized MDCK II cells. Moreover, immune-electron microscopy images of MDCK II cells overexpressing cystinosin-LKG-RFP showed stacked lamellar membranes inside perinuclear lysosomal structures. To study the role of LKG-isoform, we have investigated cystine accumulation and apoptosis that have been described in cystinotic cells. Cystinosin-LKG decreased cystine levels by approximately 10-fold similarly to cystinosin-RFP. The levels of TNFα- and actinomycin D-inducted apoptosis dropped in cystinotic cells expressing LKG-isoform. This effect was also similar to the main isoform. CONCLUSION: Our results suggest that cystinosin-LKG and cystinosin move similar functional activities in cells.
BACKGROUND:Nephropathic cystinosis is a lysosomal storage disease that is caused by mutations in the CTNS gene encoding a cystine/proton symporter cystinosin and an isoform cystinosin-LKG which is generated by an alternative splicing of exon 12. We have investigated the physiological role of the cystinosin-LKG that is widely expressed in epithelial tissues. METHODS: We have analyzed the intracellular localization and the function of the cystinosin-LKG conjugated with DsRed (cystinosin-LKG-RFP) in Madin-Darby canine kidney cells (MDCK II) and in proximal tubular epithelial cells carrying a deletion of the CTNS gene (cystinotic PTEC), respectively. RESULTS:Cystinosin-LKG-RFP colocalized with markers of lysosomes, late endosomes and was also expressed on the apical surface of polarized MDCK II cells. Moreover, immune-electron microscopy images of MDCK II cells overexpressing cystinosin-LKG-RFP showed stacked lamellar membranes inside perinuclear lysosomal structures. To study the role of LKG-isoform, we have investigated cystine accumulation and apoptosis that have been described in cystinotic cells. Cystinosin-LKG decreased cystine levels by approximately 10-fold similarly to cystinosin-RFP. The levels of TNFα- and actinomycin D-inducted apoptosis dropped in cystinotic cells expressing LKG-isoform. This effect was also similar to the main isoform. CONCLUSION: Our results suggest that cystinosin-LKG and cystinosin move similar functional activities in cells.
Authors: Ahmed Reda; Koenraad Veys; Prashant Kadam; Anna Taranta; Laura Rita Rega; Bianca M Goffredo; Chelsea Camps; Martine Besouw; Daniel Cyr; Maarten Albersen; Carl Spiessens; Liesbeth de Wever; Robert Hamer; Mirian C H Janssen; Kathleen D'Hauwers; Alex Wetzels; Leo Monnens; Lambertus van den Heuvel; Ellen Goossens; Elena Levtchenko Journal: J Inherit Metab Dis Date: 2021-09-24 Impact factor: 4.750
Authors: Francesco Bellomo; Ester De Leo; Anna Taranta; Laura Giaquinto; Gianna Di Giovamberardino; Sandro Montefusco; Laura Rita Rega; Anna Pastore; Diego Luis Medina; Diego Di Bernardo; Maria Antonietta De Matteis; Francesco Emma Journal: Int J Mol Sci Date: 2021-11-27 Impact factor: 5.923
Authors: Domenico De Rasmo; Anna Signorile; Ester De Leo; Elena V Polishchuk; Anna Ferretta; Roberto Raso; Silvia Russo; Roman Polishchuk; Francesco Emma; Francesco Bellomo Journal: Int J Mol Sci Date: 2019-12-26 Impact factor: 5.923
Authors: Anna Taranta; Mohamed A Elmonem; Francesco Bellomo; Ester De Leo; Sara Boenzi; Manoe J Janssen; Amer Jamalpoor; Sara Cairoli; Anna Pastore; Cristiano De Stefanis; Manuela Colucci; Laura R Rega; Isabella Giovannoni; Paola Francalanci; Lambertus P van den Heuvel; Carlo Dionisi-Vici; Bianca M Goffredo; Rosalinde Masereeuw; Elena Levtchenko; Francesco Emma Journal: Cells Date: 2021-11-24 Impact factor: 6.600