Premium
Interleukin‐6 Mediated Regulation of ENaC via Time‐Dependent MAPK Family Activation
Author(s) -
Srinivasan Harini,
Moseley Auriel,
Song Chang,
Tansey Malu,
Yoshigi Masaaki,
Eaton Douglas,
Wynne Brandi
Publication year - 2021
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2021.35.s1.02462
Subject(s) - mapk/erk pathway , transcriptome , activator (genetics) , aldosterone , endocrinology , mineralocorticoid receptor , kinase , medicine , signal transduction , microbiology and biotechnology , biology , receptor , chemistry , gene expression , gene , biochemistry
Hypertension (HTN) is an inflammatory disease which can be attributed to excessive sodium (Na + ) reabsorption by cells in the aldosterone‐sensitive distal nephron (ASDN), resulting in decreased water excretion and a systemic increase in blood pressure. The need for rapid identification of new therapies is important, since anti‐hypertensive drugs are often unsuccessful in regulating blood pressure. Interleukin‐6 (IL6) levels are consistently increased in plasma from hypertensive individuals. Additionally, our previous data suggests that IL6 can activate the mineralocorticoid receptor (MR) both in vitro and in vivo , as well as increase blood pressure. However, the exact intracellular signaling pathways are unknown. We first utilized RNA sequencing (RNAseq) to uncover novel targets. These studies used the mDCT15 cell model for the DCT2; cells were treated with IL6 (100ng/mL, 24 hours) or vehicle (n=4, each), then total RNA isolated. Data from the Illumina‐sequenced transcriptome underwent comparative analysis to identify significant differentially expressed transcripts between vehicle and IL6 treated cells. These experiments revealed an intricate pathway for the family of mitogen‐activated protein kinases (MAPKs). We observed significant reductions in Map3k11 (padj, 0.01), along with Mapk8ip3 (padj, 0.02) expression following IL6 treatment. Both are important modulators of the JNK pathway. Map3k11 , also known as JNK‐activator, MLK3. Mapk8ip3 encodes for JNK‐scaffolding activator, JIP3. We hypothesized that the MAPK pathways are a downstream regulator of IL6. Using total protein from IL6 treated cells (15‐30min), we observed a strong increase in pERK1/2 expression, with no changes in total ERK1/2 levels. To explore the role for ERK1/2 in ENaC activation, we measured transepithelial voltage and resistance using a voltohmmeter, and calculated current in mDCT15 cells (n=3/group) following IL6 treatment (1hr) and with an ERK1/2 inhibitor. IL6 increased amiloride‐sensitive current, which was reduced with ERK1/2 inhibition. Together, these data suggest an immediate increase in pERK1/2 activation, which was followed with an increase in ENaC activation. Interestingly, we observed an inhibition in the JNK‐pathway members with 24hr IL6 stimulation, suggestion a negative feedback regulation. These data support a time‐sensitive role for IL6‐mediated ENaC activation via MAPKs in the distal tubule and represent novel targets for alternate IL6‐mediated MR activation.