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Local synthesis of interferon-alpha in lupus nephritis is associated with type I interferons signature and LMP7 induction in renal tubular epithelial cells.

Castellano G, Cafiero C, Divella C, Sallustio F, Gigante M, Pontrelli P, De Palma G, Rossini M, Grandaliano G, Gesualdo L - Arthritis Res. Ther. (2015)

Bottom Line: Type I interferons signature was characterized by MXA-specific staining in renal tubular epithelial cells; in addition, in situ hybridization showed that renal tubular epithelial cells were the major producers of interferon-alpha, indicating a potential autocrine effect.Whole-genome expression profile showed interferon-alpha induced up-regulation of genes involved in innate immunity, protein ubiquitination and switching to immunoproteasome.Our data indicate that type I interferons might have a pathogenic role in lupus nephritis characterized by an autocrine effect of interferon-alpha on renal tubular epithelial cells.

View Article: PubMed Central - PubMed

Affiliation: Renal, Dialysis and Transplantation Unit, Department of Emergency and Organ Transplantation, University of Bari, Piazza Giulio Cesare 11, 70124, Bari, Italy. giuseppe.castellano@uniba.it.

ABSTRACT

Introduction: Type I interferons are pivotal in the activation of autoimmune response in systemic lupus erythematous. However, the pathogenic role of interferon-alpha in patients affected by lupus nephritis remains uncertain. The aim of our study was to investigate the presence of a specific interferon signature in lupus nephritis and the effects of interferon-alpha at renal level.

Methods: We performed immunohistochemical analysis for MXA-protein and in situ hybridization to detect interferon-alpha signature and production in human lupus nephritis. Through microarray studies, we analyzed the gene expression profile of renal tubular epithelial cells, stimulated with interferon-alpha. We validated microarray results through real-time polymerase chain reaction, flow cytometry on renal tubular epithelial cells, and through immunohistochemical analysis and confocal microscopy on renal biopsies.

Results: Type I interferons signature was characterized by MXA-specific staining in renal tubular epithelial cells; in addition, in situ hybridization showed that renal tubular epithelial cells were the major producers of interferon-alpha, indicating a potential autocrine effect. Whole-genome expression profile showed interferon-alpha induced up-regulation of genes involved in innate immunity, protein ubiquitination and switching to immunoproteasome. In accordance with the in vitro data, class IV lupus nephritis showed up-regulation of the immunoproteasome subunit LMP7 in tubular epithelial cells associated with type I interferon signature.

Conclusions: Our data indicate that type I interferons might have a pathogenic role in lupus nephritis characterized by an autocrine effect of interferon-alpha on renal tubular epithelial cells. Therefore we hypothesize that inhibition of type I interferons might represent a therapeutic target to prevent tubulo-interstitial damage in patients with lupus nephritis.

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Identification of IFN-alpha mRNA in renal tubular epithelial cells of patients affected by lupus nephritis. (A) ß-actin and (B) scramble mRNA expression on seriate sections of patients affected by class IV lupus nephritis, representing the positive and negative controls of the ISH reaction, respectively. (C,D,E). ISH mRNA detection on renal biopsies showed that IFN-alpha mRNA was highly expressed in epithelial cells of proximal tubules in patients with class IV lupus nephritis but it was absent in glomeruli, blood vessels and distal tubules. On the contrary, (F) IFN-alpha mRNA was marginally expressed in class I lupus nephritis. ISH analysis was performed on renal biopsies of four patients for each group, as described on Methods section. ISH, in situ hydridization.
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Fig2: Identification of IFN-alpha mRNA in renal tubular epithelial cells of patients affected by lupus nephritis. (A) ß-actin and (B) scramble mRNA expression on seriate sections of patients affected by class IV lupus nephritis, representing the positive and negative controls of the ISH reaction, respectively. (C,D,E). ISH mRNA detection on renal biopsies showed that IFN-alpha mRNA was highly expressed in epithelial cells of proximal tubules in patients with class IV lupus nephritis but it was absent in glomeruli, blood vessels and distal tubules. On the contrary, (F) IFN-alpha mRNA was marginally expressed in class I lupus nephritis. ISH analysis was performed on renal biopsies of four patients for each group, as described on Methods section. ISH, in situ hydridization.

Mentions: To investigate the possible local synthesis of IFN-alpha, we performed in situ hybridization to detect specific mRNA expression (Figure 2). We found that IFN-alpha mRNA was particularly expressed in tubular epithelial cells at the intracellular level (Figure 2C,D; arrows) but also on the luminal side of the tubules in the brush border (Figure 2E; arrows) in patients with class IV lupus nephritis. On the contrary, IFN-alpha mRNA expression was absent in class I/II (Figure 2F).Figure 2


Local synthesis of interferon-alpha in lupus nephritis is associated with type I interferons signature and LMP7 induction in renal tubular epithelial cells.

Castellano G, Cafiero C, Divella C, Sallustio F, Gigante M, Pontrelli P, De Palma G, Rossini M, Grandaliano G, Gesualdo L - Arthritis Res. Ther. (2015)

Identification of IFN-alpha mRNA in renal tubular epithelial cells of patients affected by lupus nephritis. (A) ß-actin and (B) scramble mRNA expression on seriate sections of patients affected by class IV lupus nephritis, representing the positive and negative controls of the ISH reaction, respectively. (C,D,E). ISH mRNA detection on renal biopsies showed that IFN-alpha mRNA was highly expressed in epithelial cells of proximal tubules in patients with class IV lupus nephritis but it was absent in glomeruli, blood vessels and distal tubules. On the contrary, (F) IFN-alpha mRNA was marginally expressed in class I lupus nephritis. ISH analysis was performed on renal biopsies of four patients for each group, as described on Methods section. ISH, in situ hydridization.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4389585&req=5

Fig2: Identification of IFN-alpha mRNA in renal tubular epithelial cells of patients affected by lupus nephritis. (A) ß-actin and (B) scramble mRNA expression on seriate sections of patients affected by class IV lupus nephritis, representing the positive and negative controls of the ISH reaction, respectively. (C,D,E). ISH mRNA detection on renal biopsies showed that IFN-alpha mRNA was highly expressed in epithelial cells of proximal tubules in patients with class IV lupus nephritis but it was absent in glomeruli, blood vessels and distal tubules. On the contrary, (F) IFN-alpha mRNA was marginally expressed in class I lupus nephritis. ISH analysis was performed on renal biopsies of four patients for each group, as described on Methods section. ISH, in situ hydridization.
Mentions: To investigate the possible local synthesis of IFN-alpha, we performed in situ hybridization to detect specific mRNA expression (Figure 2). We found that IFN-alpha mRNA was particularly expressed in tubular epithelial cells at the intracellular level (Figure 2C,D; arrows) but also on the luminal side of the tubules in the brush border (Figure 2E; arrows) in patients with class IV lupus nephritis. On the contrary, IFN-alpha mRNA expression was absent in class I/II (Figure 2F).Figure 2

Bottom Line: Type I interferons signature was characterized by MXA-specific staining in renal tubular epithelial cells; in addition, in situ hybridization showed that renal tubular epithelial cells were the major producers of interferon-alpha, indicating a potential autocrine effect.Whole-genome expression profile showed interferon-alpha induced up-regulation of genes involved in innate immunity, protein ubiquitination and switching to immunoproteasome.Our data indicate that type I interferons might have a pathogenic role in lupus nephritis characterized by an autocrine effect of interferon-alpha on renal tubular epithelial cells.

View Article: PubMed Central - PubMed

Affiliation: Renal, Dialysis and Transplantation Unit, Department of Emergency and Organ Transplantation, University of Bari, Piazza Giulio Cesare 11, 70124, Bari, Italy. giuseppe.castellano@uniba.it.

ABSTRACT

Introduction: Type I interferons are pivotal in the activation of autoimmune response in systemic lupus erythematous. However, the pathogenic role of interferon-alpha in patients affected by lupus nephritis remains uncertain. The aim of our study was to investigate the presence of a specific interferon signature in lupus nephritis and the effects of interferon-alpha at renal level.

Methods: We performed immunohistochemical analysis for MXA-protein and in situ hybridization to detect interferon-alpha signature and production in human lupus nephritis. Through microarray studies, we analyzed the gene expression profile of renal tubular epithelial cells, stimulated with interferon-alpha. We validated microarray results through real-time polymerase chain reaction, flow cytometry on renal tubular epithelial cells, and through immunohistochemical analysis and confocal microscopy on renal biopsies.

Results: Type I interferons signature was characterized by MXA-specific staining in renal tubular epithelial cells; in addition, in situ hybridization showed that renal tubular epithelial cells were the major producers of interferon-alpha, indicating a potential autocrine effect. Whole-genome expression profile showed interferon-alpha induced up-regulation of genes involved in innate immunity, protein ubiquitination and switching to immunoproteasome. In accordance with the in vitro data, class IV lupus nephritis showed up-regulation of the immunoproteasome subunit LMP7 in tubular epithelial cells associated with type I interferon signature.

Conclusions: Our data indicate that type I interferons might have a pathogenic role in lupus nephritis characterized by an autocrine effect of interferon-alpha on renal tubular epithelial cells. Therefore we hypothesize that inhibition of type I interferons might represent a therapeutic target to prevent tubulo-interstitial damage in patients with lupus nephritis.

Show MeSH
Related in: MedlinePlus