Activation of the kidney sodium chloride cotransporter by the β2-adrenergic receptor agonist salbutamol increases blood pressure

Abstract

The thiazide-sensitive sodium-chloride-cotransporter (NCC) in the kidney distal convoluted tubule (DCT) plays an essential role in sodium and potassium homeostasis. Here, we demonstrate that NCC activity is increased by the b2adrenoceptor agonist salbutamol, a drug prevalently used to treat asthma. Relative to b1-adrenergic receptors, the b2-adrenergic receptors were greatly enriched in mouse DCT cells. In mice, administration of salbutamol increased NCC phosphorylation (indicating increased activity) within 30 minutes but also caused hypokalemia, which also increases NCC phosphorylation. In ex vivo kidney slices and isolated tubules, salbutamol increased NCC phosphorylation in the pharmacologically relevant range of 0.01-10 mM, an effect observed after 15 minutes and maintained at 60 minutes. Inhibition of the inwardly rectifying potassium channel (Kir) 4.1 or the downstream with-no-lysine kinases (WNKs) and STE20/SPS1-related proline alanine-rich kinase (SPAK) pathway greatly attenuated, but did not prevent, salbutamol-induced NCC phosphorylation. Salbutamol increased cAMP in tubules, kidney slices and mpkDCT cells (model of DCT). Phosphoproteomics indicated that protein phosphatase 1 (PP1) was a key upstream regulator of salbutamol effects. A role for PP1 and the PP1 inhibitor 1 (I1) was confirmed in tubules using inhibitors of PP1 or kidney slices from I1 knockout mice. On normal and high salt diets, salbutamol infusion increased systolic blood pressure, but this increase was normalized by thiazide suggesting a role for NCC. Thus, b2-adrenergic receptor signaling modulates NCC activity via I1/PP1 and WNK-dependent pathways, and chronic salbutamol administration may be a risk factor for hypertension.

Activation of the Thiazide-Sensitive Sodium-Chloride Cotransporter by Beta3-Adrenoreceptor in the Distal Convoluted Tubule

“…On the other hand, Terker et al showed that acute adrenergic stimulation increased the abundance of pNCC via BAR1 stimulation in mice (Terker et al, 2014). More recently, it has been shown that pharmacological stimulation of BAR2 with salbutamol increases both NCC phosphorylation and systolic blood pressure, the latter effect blunted by thiazide (Poulsen et al, 2021). In the present study, we demonstrated that also BAR3 plays an additional, crucial role in NCC modulation.…”

“…Our hypothesis is indeed that the reduction of WNK-SPAK signaling in the kidney upon BAR3 ko induces the reduction of NCC phosphorylation and activity in these mice. Although BAR2 is also involved in the activation of SPAK and WNK (Poulsen et al, 2021), in the kidney of BAR1/2 ko mice, the activity of SPAK and WNK resulted almost normal or slightly upregulated compared to their controls, thus suggesting that BAR3 alone is sufficient to preserve the WNK-SPAK pathway activation in the kidney under sympathetic stimulation.…”

“…Here, we focused on the possible functional role of BAR3 in DCT where it localized at the basolateral membrane of epithelial cells expressing the thiazide-sensitive sodium-chloride cotransporter (NCC) at the apical side (Procino et al, 2016;Poulsen et al, 2021). NCC tightly tunes renal sodium reabsorption in DCT to fit blood pressure changes.…”

Dissecting the Effects of Aldosterone and Hypokalemia on the Epithelial Na+ Channel and the NaCl Cotransporter

“…Tubules were then allowed to sediment whereafter media was removed and replaced by 3 ml media with the desired aldosterone and K + concentrations. Tubules were then incubated at 37°C and 5% CO 2 for 21 h. Preincubation of tubules for 21 h and subsequent exposure to 10 µM salbutamol for 2 h (Selleckchem, Houston, TX) increased pT58-NCC [ Supplementary Figure S4 ( Poulsen et al, 2021 ),], thus documenting the viability of the tubules.…”

Potassium Effects on NCC Are Attenuated during Inhibition of Cullin E3–Ubiquitin Ligases

“…Altered plasma K + levels per se observed during altered K + intake also modulate NCC abundance and phosphorylation by the modulation of the WNK–SPAK/OSR1 pathway [ 7 ]. To study the contribution of cullins in mediating the K + effects on NCC independent of other systemic factors, we used our extensively characterized ex vivo renal tubule preparations [ 24 , 43 , 44 ] and incubated them in different concentrations of K + (2.5, 3.5, or 6 mM) for 30 min or 24 h ( Figure 4 ). After 30 min, compared with 3.5 mM K + , pT58NCC and phosphorylated SPAK levels were significantly increased and decreased after incubation in low or high K + media, respectively ( Figure 4 A,B).…”