Panoply™ Human PRLR Over-expressing Stable Cell Line

Here, researchers aimed to identify novel molecular subtypes of ulcerative colitis (UC) based on a large-scale cohort study and establish a clinically applicable subtype system to promote precision medicine treatment for this disease. Three stable molecular subtypes have been successfully identified. Immune cell infiltration analysis categorizes UC into innate immune activation (IIA), fully immune activation (WIA), and immune homeostasis-like (IHL). Notably, WIA patients have the lowest response rate to biologics (less than 10%), while IHL patients have the highest response rate, ranging from 42% to 60%. Among the subtype signature genes, the ratio of PRLR to TNFSF13B can effectively screen IHL UC subtypes suitable for biologic therapy. Furthermore, researchers demonstrated that PRLR expressed in epithelial cells can inhibit TNFSF13B expression in monocyte-derived macrophages through the CXCL1-NF-κB pathway.

Here, the researchers divided Caco-2 cells into two groups: overexpressing and wild-type PRLR (PRLR-OE or PRLR-WT), and stimulated them with 1 μg/mL LPS for 48 hours. The culture supernatants of these Caco-2 cells were then collected and used to stimulate THP-1 cells pretreated with PMA. As expected, the expression of TNFSF13B in THP-1 cells in the culture supernatant derived from PRLR-overexpressing Caco-2 was much lower than that in the culture supernatant derived from PRLR-WT Caco-2, which was confirmed at both the mRNA and protein levels (Figure 1a, b). The results showed that PRLR in epithelial cells was negatively correlated with TNFSF13B in macrophages. At the same time, RNA sequencing was performed on PRLR-WT and PRLR-overexpressing Caco-2 cells after 48 hours of LPS stimulation. Interestingly, KEGG enrichment analysis of significantly downregulated DEGs revealed that cytokine-cytokine receptor interaction was downregulated in the PRLR-overexpressing Caco-2 group compared with the PRLR-WT Caco-2 group (Figure 1c). Among the downregulated genes involved in the cytokine-cytokine receptor interaction pathway, CXCL1 had the largest fold change when comparing the PRLR-overexpressing Caco-2 group with the PRLR-WT Caco-2 group (Figure 1d). Furthermore, scRNA sequencing results from GSE182270 revealed that epithelial cells are one of the two major sources of CXCL1, while other cytokines are rarely expressed in epithelial cells (Figure 1e). Consistently, additional CXCL1, especially at a concentration of 100 nM, restored the expression level of TNFSF13B in THP-1 cells stimulated with PRLR-overexpressing Caco-2 supernatant (Figure 1f). Furthermore, treatment with the CXCR2 inhibitor SB225002 abolished the above phenomena, indicating that PRLR-mediated downregulation of TNFSF13B in THP-1 cells is dependent on the reduction of CXCL1 secretion in Caco-2 cells.

Figure 1. Epithelial PRLR inhibited TNFSF13B of macrophages through attenuated CXCL1-NF-κB signaling. (Mo S, et al., 2023)