Transcription factor Fli-1 impacts the expression of CXCL13 and regulates immune cell infiltration into the kidney in MRL/lpr mouse

Abstract

ObjectiveFriend leukaemia virus integration 1 (Fli-1) regulates chemokine/cytokine expression and thus plays an important role in the development of lupus nephritis. Chemokine CXC ligand 13 (CXCL13) is a chemokine that promotes the formation of ectopic lymphoid structures and has been reported to be associated with the pathogenesis of lupus nephritis. The relationship between Fli-1 and CXCL13 is unknown. This study aims to elucidate whether Fli-1 impacts CXCL13 expression and contributes to the progression of lupus-like nephritis in adult MRL/lpr mouse.MethodsSerum CXCL13 levels were measured in adult wild-type (WT) MRL/lpr mice and Fli-1 heterozygote knockout (Fli-1+/−) MRL/lpr mice (4 months old or older) using ELISA. Renal mRNA expression (CXCL13 and related molecules) was measured using real-time PCR method. Kidneys were removed, stained and evaluated using a pathology scoring system. The grade of CXCL13 or CXC-chemokine receptor type 5 (CXCR5)-positive immune cell infiltration into the kidney was evaluated using immunostaining with anti-CXCL13 or anti-CXCR5 antibodies. We also used immunofluorescence staining with CXCL13- and CD11b-specific antibodies to detect the infiltration of CXCL13/CD11b double-positive immune cells.ResultsSerum CXCL13 levels in Fli-1+/−MRL/lpr mice were significantly lower than that in WT MRL/lpr mice (545.5 and 960.5 pg/mL, p=0.02). Renal expression of CXCL13 mRNA and SRY-related HMG box4 (Sox4) (an important factor for B-cell development) levels were significantly lower in Fli-1+/−MRL/lpr mice. Renal histology scores in WT MRL/lpr mice revealed significantly increased glomerular inflammation. Despite similar interstitial immune cell infiltration into the kidney, the number of CXCL13- and CXCR5-positive cells was significantly lower in Fli-1+/−MRL/lpr mice than in WT mice. Furthermore, immunofluorescence staining revealed that Fli-1+/-MRL/lpr mice had significantly fewer CXCL13/CD11b double-positive immune cells.ConclusionFli-1 regulates renal Sox4 mRNA expression and infiltration of CXCR5-positive cells as well as CXCL13/CD11b double-positive immune cells into the kidney, which affects CXCL13 expression and lupus-like nephritis.

Targeting Fli‐1 and chemokine axis CXCL10/CXCL13/CXCR3 in systemic lupus erythematosus and lupus nephritis

“…In Fli-1 +/− MRL/lpr mice, there was low level of CCL2, CCL3, CCL4, CCL5, STAT3, CXCR3, CXCR5, CXCL9, CXCL10, CXCL13, SRY-related HMG box4 (Sox4), neuraminidase 1 (NEU1), NEU3, and each of the major lactosylceramide (LacCer) species (C16, C22, C24, and C24:1), total LacCer in the kidney relative to those in controls. 1,2,[23][24][25][26] There were reduced serum levels of total IgG, IgG1, and IgG3, CXCL13, IL-6, IL-17A, anti-dsDNA, decreased urine protein levels in lupus mice, and serum concentrations of anti-dsDNA were positively related to IL-6 levels. 2,21,23,25,27 Interestingly, there were severe glomerular inflammation in Fli-1 +/+ group when compared to that in Fli-1 to levels of CCL4, CCL5 from kidney in Fli-1 +/− group.…”

“…1,2,[23][24][25][26] There were reduced serum levels of total IgG, IgG1, and IgG3, CXCL13, IL-6, IL-17A, anti-dsDNA, decreased urine protein levels in lupus mice, and serum concentrations of anti-dsDNA were positively related to IL-6 levels. 2,21,23,25,27 Interestingly, there were severe glomerular inflammation in Fli-1 +/+ group when compared to that in Fli-1 to levels of CCL4, CCL5 from kidney in Fli-1 +/− group. 25 Moreover, migration of the inflammatory cells (CD3 + IL-17A + T cells, CD19 + B cells, CD11b + CXCL13 + cells) in Fli-1 +/− group in response to CCL2, CCL4, CCL5 reduced in relative to the migration in control mice.…”

“…Kidney of Fli-1 +/− group revealed less CXCL13 + cells in tertiary lymphoid structure (TLS) lesions and interstitial inflammatory lesions as well as limited IL-17A positive cells in the tubulointerstitial lesion. It is notable that infiltration of CD11b + CCL20 + monocytes, CXCR3 + T cells, CD19 + B cells, CD11b + CXCL13 + cells in kidneys was noted in control mice, whereas there was no infiltration of CD11b + CCL20 + monocytes, CXCR3 + T cells, CD19 + B cells, CD11b + CXCL13 + cells from Fli-1 +/− group, and glomerular histological score was positively related to proportion of CD11b + CXCL13 + cells in kidneys 2,[23][24][25][26][27]. Number of inflammatory cells CD3 + IL-17A + T cells, CD11b + CXCL13 + cells from kidneys was related…”

Tertiary lymphoid structures as local perpetuators of organ-specific immune injury: implication for lupus nephritis

“…Subsequently, transcriptomic studies of LN kidneys in MRL/lpr and BXSB models showed increased cxcl13/cxcr5 along with upregulated expression signature associated with TLS formation (63), suggesting a role of CXCL13/CXCR5 in TLS formation in LN. In animal studies, BAFF, TLR7 signaling, and Fli-1 have also been suggested to play a role in TLS formation (54, 65,71). These and other molecular and cellular mechanisms associated with TLS formation in lupus are described in Table 3.…”

USP25 attenuates anti-GBM nephritis in mice by negative feedback regulation of Th17 cell differentiation

“…(4) When wild-type mice with nephritis are treated with anti-IL-17F neutralizing antibodies, histological damage scores are significantly reduced compared to those treated with isotype antibody [ 12 ]. (5) IL-17F-deficient lupus mice exhibit reduced mortality and albuminuria compared to regular lupus mice [ 13 ]. (6) RORγt, a crucial transcription factor in Th17-cell development, has been shown to promote CGN [ 14 ].…”