Grazia Serino1, Fabio Sallustio2, Claudia Curci3, Sharon N Cox4, Francesco Pesce5, Giuseppe De Palma3, Francesco P Schena6. 1. Department of Emergency and Organ Transplantation, University of Bari, Bari, Italy C.A.R.S.O. Consortium, University of Bari, Valenzano (Ba), Italy. 2. C.A.R.S.O. Consortium, University of Bari, Valenzano (Ba), Italy Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali (DiSTeBA), Università del Salento, Monteroni, Lecce, Italy. 3. C.A.R.S.O. Consortium, University of Bari, Valenzano (Ba), Italy. 4. Department of Emergency and Organ Transplantation, University of Bari, Bari, Italy. 5. Department of Emergency and Organ Transplantation, University of Bari, Bari, Italy Cardiovascular Genetics and Genomics, National Heart and Lung Institute, Imperial College London, London, UK. 6. C.A.R.S.O. Consortium, University of Bari, Valenzano (Ba), Italy Schena Foundation, Research Center for Kidney Diseases, Valenzano (Ba), Italy.
Abstract
BACKGROUND: IgA nephropathy (IgAN) is characterized by aberrant O-glycosylation in the hinge region of IgA1. The early step in O-glycan formation is the attachment of N-acetylgalactosamine (GalNAc) to the serine/threonine of the hinge region; the process is catalysed by UDP-N-acetyl-α-d-galactosamine:polypeptide N-acetylgalactosaminyltransferase 2 (GALNT2). In our previous work, the microarray analysis on peripheral blood mononuclear cells (PBMCs) identified an upregulated miRNA called let-7b. METHODS: To study the molecular mechanisms in which let-7b was involved, we performed a bioinformatic analysis to predict their target genes. To validate biologically let-7b targets, we performed transient transfection experiments ex vivo using PBMCs from an independent group of IgAN patients and healthy blood donors (HBDs). RESULTS: Bioinformatic analysis revealed that GALNT2 is the potential target of let-7b. We found this miRNA significantly upregulated in PBMCs of IgAN patients compared with HBDs. Then, we demonstrated in ex-vivo experiments that let-7b decreased GALNT2 levels in PBMCs of IgAN patients, whereas the loss of let-7b function in PBMCs of HBDs led to an increase of GALNT2 mRNA and its protein level. Finally, we found that upregulation of let-7b occurred also in B-lymphocytes from IgAN patients. CONCLUSIONS: Our results give novel additional information on the abnormal O-glycosylation process of IgA1 in IgAN patients. This study provides evidence for another important miRNA-based regulatory mechanism of the O-glycosylation process in which the deregulated expression of let-7b is associated with altered expression of GALNT2. This finding could be taken into consideration for new therapeutic approaches in IgAN because other serum glycosylated proteins do not display abnormal glycosylation.
BACKGROUND:IgA nephropathy (IgAN) is characterized by aberrant O-glycosylation in the hinge region of IgA1. The early step in O-glycan formation is the attachment of N-acetylgalactosamine (GalNAc) to the serine/threonine of the hinge region; the process is catalysed by UDP-N-acetyl-α-d-galactosamine:polypeptide N-acetylgalactosaminyltransferase 2 (GALNT2). In our previous work, the microarray analysis on peripheral blood mononuclear cells (PBMCs) identified an upregulated miRNA called let-7b. METHODS: To study the molecular mechanisms in which let-7b was involved, we performed a bioinformatic analysis to predict their target genes. To validate biologically let-7b targets, we performed transient transfection experiments ex vivo using PBMCs from an independent group of IgANpatients and healthy blood donors (HBDs). RESULTS: Bioinformatic analysis revealed that GALNT2 is the potential target of let-7b. We found this miRNA significantly upregulated in PBMCs of IgANpatients compared with HBDs. Then, we demonstrated in ex-vivo experiments that let-7b decreased GALNT2 levels in PBMCs of IgANpatients, whereas the loss of let-7b function in PBMCs of HBDs led to an increase of GALNT2 mRNA and its protein level. Finally, we found that upregulation of let-7b occurred also in B-lymphocytes from IgANpatients. CONCLUSIONS: Our results give novel additional information on the abnormal O-glycosylation process of IgA1 in IgANpatients. This study provides evidence for another important miRNA-based regulatory mechanism of the O-glycosylation process in which the deregulated expression of let-7b is associated with altered expression of GALNT2. This finding could be taken into consideration for new therapeutic approaches in IgAN because other serum glycosylated proteins do not display abnormal glycosylation.
Authors: Taylor Person; R Glenn King; Dana V Rizk; Jan Novak; Todd J Green; Colin Reily Journal: J Interferon Cytokine Res Date: 2022-07-06 Impact factor: 3.657
Authors: Clemens L Bockmeyer; Karen Säuberlich; Juliane Wittig; Marc Eßer; Sebastian S Roeder; Udo Vester; Peter F Hoyer; Putri A Agustian; Philip Zeuschner; Kerstin Amann; Christoph Daniel; Jan U Becker Journal: Sci Rep Date: 2016-08-24 Impact factor: 4.379