NSSR1 is regulated by testosterone in the mouse uterus and extensively expressed in endometrial carcinoma

SRSF10-mediated IL1RAP alternative splicing regulates cervical cancer oncogenesis via mIL1RAP-NF-κB-CD47 axis

High-risk human papillomavirus oncoproteins E6 and E7 are the major etiological factors of cervical cancer but are insufficient for malignant transformation of cervical cancer. Dysregulated alternative splicing, mainly ascribed to aberrant splicing factor levels and activities, contributes to most cancer hallmarks. However, do E6 and E7 regulate the expression of splicing factors? Does alternative splicing acts as an “accomplice” of E6E7 to promote cervical cancer progression? Here, we identified that the splicing factor SRSF10, which promotes tumorigenesis of cervix, was upregulated by E6E7 via E2F1 transcriptional activation. SRSF10 modulates the alternate terminator of interleukin-1 receptor accessory protein exon 13 to increase production of the membrane form of interleukin-1 receptor accessory protein. SRSF10-mediated mIL1RAP upregulates the expression of the “don’t eat me” signal CD47 to inhibit macrophage phagocytosis by promoting nuclear factor-κB activation, which is pivotal in inflammatory, immune, and tumorigenesis processes. Altogether, these data reveal a close relationship among HPV infection, alternative splicing and tumor immune evasion, and also suggests that the SRSF10-mIL1RAP-CD47 axis could be an attractive therapeutic target for the treatment of cervical cancer.

Dephosphorylated NSSR1 is induced by androgen in mouse epididymis and phosphorylated NSSR1 is increased during sperm maturation

NSSR1 (Neural salient serine/arginine rich protein 1, alternatively SRp38) is a newly identified RNA splicing factor and predominantly expressed in neural tissues. Here, by Western blot analysis and immunofluorescent staining, we showed that the expression of dephosphorylated NSSR1 increased significantly during development of the caput epididymis. In adult mice, phosphorylated NSSR1 was mainly expressed in the apical side of epithelial cells, and dephosphorylated NSSR1 in caput epididymis was upregulated in a testosterone dependent manner. In addition, subcellular immunoreactive distribution of NSSR1 varied in different regions of the epididymis. With respect to the sperm, phosphorylated NSSR1 was detected in the mid-piece of the tail as well as the acrosome. Furthermore, NSSR1 was released from the sperm head during the capacitation and acrosome reaction. These findings for the first time provide the evidence for the potential roles of NSSR1 in sperm maturation and fertilization.