Fig. 6

Aberrant Cx43 hemichannel activity regulates NLRP3 priming and activation via P2X7R in hPTECs. To investigate if NLRP3 priming/activation is driven by a Cx43 mediated ATP-P2X7R signalling axis, we established a role for non-hydrolysable ATPγS in increasing expression of the NLRP3 inflammasome and associated downstream mediators, e.g., IL1β, IL6, caspase 1 and caspase 1 (a). Analysis of published transcriptome datasets determined that P2X7R is upregulated in patients with CKD (b) (n = 48 patients). Evidenced by increased IL1β (c), IL18 (d), and NLRP3 transcription (e), qRT-PCR analysis determined that treatment of hPTECS with TGF-β1 induced NLRP3 priming. Inflammasome activation was blunted when TGF-β1 treated hPTECS were pre-incubated with a P2X7R antagonist (A438079), as evidenced by a reduction in protein expression of NLRP3 signalling mediators (f) and caspase 1 activity (g). All groups are n = 3–4. ANOVA and a Tukey post-test was used for experimental comparisons except for transcriptomic data where Welch’s correction was used. *P < 0.05, **P < 0.01, ***P < 0.001 and ****P < 0.0001