Anti-Tyrosine polyclonal antibody

Several lines of evidence suggest that the aggregation and deposition of amyloid-beta peptide (A beta) initiate the pathology of Alzheimer's disease (AD). Recently, a genome-wide association study demonstrated that a single-nucleotide polymorphism proximal to the EPHA4 gene, which encodes a receptor tyrosine kinase, is associated with AD risk. However, the molecular mechanism of EphA4 in the pathogenesis of AD, particularly in A beta production, remains unknown. Here, we performed several pharmacological and biological experiments both in vitro and in vivo and demonstrated that EphA4 is responsible for the regulation of A beta production. Pharmacological inhibition of EphA4 signaling and knockdown of Epha4 led to increased A beta levels accompanied by increased expression of beta-site APP cleaving enzyme 1 (BACE1), which is an enzyme responsible for A beta production. Moreover, EPHA4 overexpression and activation of EphA4 signaling via ephrin ligands decreased A beta levels. In particular, the sterile-alpha motif domain of EphA4 was necessary for the regulation of A beta production. Finally, EPHA4 mRNA levels were significantly reduced in the brains of AD patients, and negatively correlated with BACE1 mRNA levels. Our results indicate a novel mechanism of A beta regulation by EphA4, which is involved in AD pathogenesis.

Interleukin-17 receptor D (IL-17RD), also known as similar expression to Fgf genes (SEF), is proposed to act as a signaling hub that negatively regulates mitogenic signaling pathways, like the ERK1/2 MAP kinase pathway, and innate immune signaling. The expression of IL-17RD is downregulated in certain solid tumors, which has led to the hypothesis that it may exert tumor suppressor functions. However, the role of IL-17RD in tumor biology remains to be studied in vivo. Here, we show that genetic disruption of Il17rd leads to the increased formation of spontaneous tumors in multiple tissues of aging mice. Loss of IL-17RD also promotes tumor development in a model of colitis-associated colorectal cancer, associated with an exacerbated inflammatory response. Colon tumors from IL-17RD-deficient mice are characterized by a strong enrichment in inflammation-related gene signatures, elevated expression of pro-inflammatory tumorigenic cytokines, such as IL-17A and IL-6, and increased STAT3 tyrosine phosphorylation. We further show that RNAi depletion of IL-17RD enhances Toll-like receptor and IL-17A signaling in colon adenocarcinoma cells. No change in the proliferation of normal or tumor intestinal epithelial cells was observed upon genetic inactivation of IL-17RD. Our findings establish IL-17RD as a tumor suppressor in mice and suggest that the protein exerts its function mainly by limiting the extent and duration of inflammation.