Role of neuropilin-2 in the immune system

Neuropilins (NRPs) are single transmembrane receptors with short cytoplasmic tails and are dependent on receptors like VEGF receptors or Plexins for signal transduction. NRPs are known to be important in angiogenesis, lymphangiogenesis, and axon guidance. The Neuropilin-family consists of two members, Neuropilin-1 (NRP1) and Neuropilin-2 (NRP2). They are up to 44 % homologous and conserved in all vertebrates. High levels of NRP2 are found on immune cells. Current research is very limited regarding the functions of NRP2 on these cells. Recent evidence suggests that NRP2 is important for migration, antigen presentation, phagocytosis and cell-cell contact within the immune system. Additionally, posttranslational NRP2 modifications like polysialylation are crucial for the function of some immune cells. This review is an overview about expression and functions of NRP2 in the immune system.

Neuropilin-2 and its ligand VEGF-C predict treatment response after transurethral resection and radiochemotherapy in bladder cancer patients

The standard treatment for invasive bladder cancer is radical cystectomy. In selected patients, bladder-sparing therapy can be performed by transurethral resection (TURBT) and radio-chemotherapy (RCT) or radiotherapy (RT). Our published in vitro data suggest that the Neuropilin-2 (NRP2)/VEGF-C axis plays a role in therapy resistance. Therefore, we studied the prognostic impact of NRP2 and VEGF-C in 247 bladder cancer patients (cN0M0) treated with TURBT and RCT (n = 198) or RT (n = 49) and a follow-up time up to 15 years. A tissue microarray was analyzed by immunohistochemistry. NRP2 expression emerged as a prognostic factor in overall survival (OS; HR: 3.42; 95% CI: 1.48 - 7.86; p = 0.004) and was associated with a 3.85-fold increased risk of an early cancer specific death (95% CI: 0.91 - 16.24; p = 0.066) in multivariate analyses. Cancer specific survival (CSS) dropped from 166 months to 85 months when NRP2 was highly expressed (p = 0.037). Patients with high VEGF-C expression have a 2.29-fold increased risk of shorter CSS (95% CI: 1.03-5.35; p = 0.043) in univariate analysis. CSS dropped from 170 months to 88 months in the case of high VEGF-C expression (p = 0.041). Additionally, NRP2 and VEGF-C coexpression is a prognostic marker for OS in multivariate models (HR: 7.54; 95% CI: 1.57-36.23; p = 0.012). Stratification for muscle invasiveness (T1 vs. T2-T4) confirmed the prognostic role of NRP2 and NRP2/VEGF-C co-expression in patients with T2-T4 but also with high risk T1 disease. In conclusion, immunohistochemistry for NRP2 and VEGF-C has been determined to predict therapy outcome in bladder cancer patients prior to TURBT and RCT.