Pancreatic cancer-associated inflammation drives dynamic regulation of p35 and Ebi3.
B cells are important modulators of immune responses both in autoimmunity and cancer. We have previously shown that B regulatory (Breg) cells promote pancreatic cancer via production of IL35, a heterodimeric cytokine comprised of the subunits p35 (Il12a) and Ebi3. However, it is not known how production of IL35 is regulated in vivo in the context of cancer-associated inflammation. To begin addressing this question, we have generated a knock-in mouse model, Il12aGFP, where an IRES-emGFP gene was inserted within the 3' UTR of the Il12a locus. EmGFP signal in B cells from the Il12aGFP mice correlated with expression of p35 mRNA and protein. Using this model, we observed that in addition to Bregs, expression of GFP (p35) is upregulated in several other B cell subtypes in response to cancer. We assessed the expression of the other IL35 subunit, Ebi3, using a published tdTomato reporter model. We determined that Ebi3 expression was more tightly regulated in vivo and in vitro, suggesting that stimuli affecting Ebi3 upregulation are more likely to result in production of full IL35 heterodimer. We were also able to detect GFP and Tomato signal in myeloid & T cell lineages suggesting that these reporter models could also be used for tracking IL12-, IL27- and IL35-producing cells. Furthermore, using primary B cells isolated from reporter mice, we identified BCR, CD40 and TLR pathways as potential drivers of IL35 expression. These findings highlight the importance of pancreatic cancer-associated inflammatory processes as drivers of cytokine expression and provide a tool to dissect both disease-associated regulation of IL12- and IL35-competent lineage cells as well as establish assays for pharmacological targeting of individual subunits of heterodimeric IL12 family cytokines.
['Michaud|Daniel|D|', 'Mirlekar|Bhalchandra|B|', 'Bischoff|Steven|S|', 'Cowley|Dale O|DO|', 'Vignali|Dario A A|DAA|', 'Pylayeva-Gupta|Yuliya|Y|']
D000818:Animals D060151:B-Lymphocytes, Regulatory D019013:CD40 Antigens D045744:Cell Line, Tumor D005434:Flow Cytometry D015972:Gene Expression Regulation, Neoplastic D007249:Inflammation D053765:Interleukin-12 Subunit p35 D007378:Interleukins D051379:Mice D018345:Mice, Knockout D015778:Minor Histocompatibility Antigens D010190:Pancreatic Neoplasms D051562:Proto-Oncogene Proteins c-bcr D018121:Receptors, Cytokine D051193:Toll-Like Receptors D015854:Up-Regulation
Pancreatic cancer Reporter model IL35 cytokine Regulatory B cell