Inhibition of suppressor of cytokine signaling 1 mediates the profibrotic effect of TWEAK/Fn14 signaling on kidney cells

SOCS-JAK-STAT inhibitors and SOCS mimetics as treatment options for autoimmune uveitis, psoriasis, lupus, and autoimmune encephalitis

Autoimmune diseases arise from atypical immune responses that attack self-tissue epitopes, and their development is intricately connected to the disruption of the JAK-STAT signaling pathway, where SOCS proteins play crucial roles. Conditions such as autoimmune uveitis, psoriasis, lupus, and autoimmune encephalitis exhibit immune system dysfunctions associated with JAK-STAT signaling dysregulation. Emerging therapeutic strategies utilize JAK-STAT inhibitors and SOCS mimetics to modulate immune responses and alleviate autoimmune manifestations. Although more research and clinical studies are required to assess their effectiveness, safety profiles, and potential for personalized therapeutic approaches in autoimmune conditions, JAK-STAT inhibitors and SOCS mimetics show promise as potential treatment options. This review explores the action, effectiveness, safety profiles, and future prospects of JAK inhibitors and SOCS mimetics as therapeutic agents for psoriasis, autoimmune uveitis, systemic lupus erythematosus, and autoimmune encephalitis. The findings underscore the importance of investigating these targeted therapies to advance treatment options for individuals suffering from autoimmune diseases.

Mesangial Cells in Lupus Nephritis

PURPOSE OF REVIEW

Mesangial cells are critical for the proper function of the glomerulus, playing roles in structural support and injury repair. However, they are also early responders to glomerular immune complex deposition and contribute to inflammation and fibrosis in lupus nephritis. This review highlights recent studies identifying signaling pathways and mediators in mesangial cell response to lupus-relevant stimuli.

RECENT FINDINGS

Anti-dsDNA antibodies, serum, or plasma from individuals with lupus nephritis, or specific pathologic factors activated multiple signaling pathways. These pathways largely included JAK/STAT/SOCS, PI3K/AKT, and MAPK and led to induction of proliferation and expression of multiple proinflammatory cytokines, growth factors, and profibrotic factors. NFκB activation was a common mediator of response. Mesangial cells proliferate and express a wide array of proinflammatory/profibrotic factors in response to a variety of lupus-relevant pathologic stimuli. While some of the responses are similar, the mechanisms involved appear to be diverse depending on the stimulus. Future studies are needed to fully elucidate these mechanisms with respect to the diverse milieu of stimuli.

Emerging role of TWEAK-Fn14 axis in lupus, a disease related to autoimmunity and fibrosis

Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder. Lupus nephritis (LN) is one of the severe clinical implications in SLE, and this was relates to fibrosis in the kidney. As an important marker in the tumor necrosis factor (TNF) superfamily, TNF-like weak inducer of apoptosis (TWEAK) has been given much attention with respect to its role in regulating pro-inflammatory immune response. Fibroblast growth factor-inducible 14 (Fn14), the sole receptor for TWEAK, has been found expressed in different immune and non-immune cells. TWEAK binds to Fn14, and then regulates inflammatory components production via downstream signaling pathways. To date, dysregulated expression of TWEAK, Fn14 has been reported in SLE, LN patients, and in vivo, in vitro studies have discussed the significant role of TWEAK-Fn14 axis in SLE, LN pathogenesis, partly through mediating the fibrosis process. In this review, we will discuss the association of TWEAK-Fn14 axis in lupus. Understanding the relationship will better realize the potential for making TWEAK-Fn14 as a marker for the diseases, and will help to give many clues for targeting them in treatment of lupus in the future.

Diagnostic value of TWEAK for predicting active lupus nephritis in patients with systemic lupus erythematosus: a systematic review and meta-analysis

Purpose

Accumulative studies showed that tumor necrosis factor (TNF)-like weak inducer of apoptosis (TWEAK) was up-regulated in the blood and urine from patients diagnosed with lupus nephritis (LN) and that it might be used as a novel biomarker for active LN. This meta-analysis aimed to determine the diagnostic value of TWEAK in active LN.

Methods

We searched the Cochrane Library, Embase, PubMed, Springer, Wanfang and CNKI databases for articles published up to 20 August 2020. The diagnostic capacity of TWEAK for active LN was assessed using pooled sensitivity and specificity, positive and negative likelihood ratios (PLR and NLR), diagnostic odds ratio (DOR), and area under the receiver operating characteristic curve (AUC). Quality assessment and publication bias were also evaluated. STATA 11.0 and Meta-Disc 1.4 were used to perform these analyses.

Results

Nine cross-sectional studies were included in this meta-analysis. The overall pooled sensitivity of TWEAK for the diagnosis of active LN was 0.69 (95% CI, 0.63–0.75), and specificity was 0.77 (95% CI, 0.71–0.82). The overall pooled PLR and NLR were 3.31 (95% CI, 2.05–5.35) and 0.38 (95% CI, 0.26–0.55), respectively, with a DOR of 10.89 (95% CI, 6.73–17.63) and AUC (SE) of 0.8276 (0.0289). Deeks’ funnel plot revealed that the publication bias was insignificant in the study (p = .32).

Conclusions

Our results suggest that TWEAK might be a potential biomarker for patients with active LN. Future cross-sectional and longitudinal studies are needed to confirm its diagnostic value, as well as to establish more definite cutoff for active LN.

Inhibition of fibroblast growth factor-inducible 14 attenuates experimental tubulointerstitial fibrosis and profibrotic factor expression of proximal tubular epithelial cells

BACKGROUND AND AIM

As a proinflammatory cytokine, tumor necrosis factor-like weak inducer of apoptosis (TWEAK) participates in the progression of renal fibrosis by binding to its receptor, fibroblast growth factor-inducible 14 (Fn14). However, the effect of Fn14 inhibition on tubular epithelial cell-mediated tubulointerstitial fibrosis remains unclear. This study aimed to elucidate the role of TWEAK/Fn14 interaction in the development of experimental tubulointerstitial fibrosis as well as the protective effect of Fn14 knockdown on proximal tubular epithelial cells.

METHODS

A murine model of unilateral ureteral obstruction was constructed in both wild-type and Fn14-deficient BALB/c mice, followed by observation of the tubulointerstitial pathologies.

RESULTS

Fn14 deficiency ameliorated the pathological changes, including inflammatory cell infiltration and cell proliferation, accompanied by reduced production of profibrotic factors and extracellular matrix deposition. In vitro experiments showed that TWEAK dose-dependently enhanced the expression of collagen I, fibronectin, and α-smooth muscle actin in proximal tubular epithelial cells. Interestingly, TWEAK also upregulated the expression levels of Notch1/Jagged1. Fn14 knockdown and Notch1/Jagged1 inhibition also mitigated the effect of TWEAK on these cells.

CONCLUSIONS

In conclusion, TWEAK/Fn14 signals contributed to tubulointerstitial fibrosis by acting on proximal tubular epithelial cells. Fn14 inhibition might be a therapeutic strategy for protecting against renal interstitial fibrosis.

TWEAK/Fn14 axis is an important player in fibrosis

Fibrosis is a common pathological condition associated with abnormal repair after tissue injury. However, the etiology and molecular mechanisms of fibrosis are still not well-understood. Tumor necrosis factor (TNF)-like weak inducer of apoptosis (TWEAK) belongs to the TNF superfamily and acts by binding to its receptor, fibroblast growth factor-inducible 14 (Fn14), thereby activating a variety of intracellular signal transduction pathways in various types of cells. Besides promoting the expression of growth factors, activation of TWEAK/Fn14 signaling after tissue injury can promote the expression of pro-inflammatory cytokines, which trigger the immune response, thereby exacerbating the injury. Severe or repetitive injury leads to a dysregulated tissue repair process, in which the TWEAK/Fn14 axis promotes the activation and proliferation of myofibroblasts, induces the secretion of the extracellular matrix, and regulates profibrotic mediators to further perpetuate and sustain the fibrotic process. In this review, we summarize the available experimental evidence on the underlying molecular mechanisms by which the TWEAK/Fn14 pathway mediates the development and progression of fibrosis. In addition, we discuss the therapeutic potential of the TWEAK/Fn14 pathway in fibrosis-associated diseases based on evidence derived from multiple models and cells from injured tissue and fibrotic tissue.

Fibroblast growth factor inducible 14 signaling facilitates anti-dsDNA IgG penetration into mesangial cells

Anti-double-stranded DNA (dsDNA) antibodies induce renal damage in patients with systemic lupus erythematosus by triggering fibrotic processes in kidney cells. However, the precise mechanism underlying penetration of anti-dsDNA immunoglubolin G (IgG) into cells remains unclear. This study was designed to investigate the effect of tumor necrosis factor-like weak inducer of apoptosis (TWEAK)/fibroblast growth factor inducible 14 (Fn14) signaling on anti-dsDNA IgG penetration into cells. Mesangial cells were cultured in vitro, and stimulated with TWEAK and anti-dsDNA IgG. The results revealed that TWEAK dose-dependently enhanced cellular internalization of anti-dsDNA IgG and the expression of high-mobility group box 1 (HMGB1). In addition, TWEAK and anti-dsDNA IgG synthetically downregulate suppressor of cytokine signaling 1, and induce the expression of various fibrotic factors. Furthermore, inhibition of HMGB1 attenuates the enhancement effect of TWEAK on anti-dsDNA IgG internalization. The TWEAK upregulation of HMGB1 involves the nuclear factor-κB and phosphatidylinositide 3-kinase/protein kinase B pathways. Therefore, TWEAK/Fn14 signaling contributes to the penetration of anti-dsDNA IgG and relevant fibrotic processes in mesangial cells.