Table 2.
In vivo and in vitro studies of GRK4 modification or variants.
GRK4 modification or variants | Animal or cell | Type of GRK4 modification | Effects of GRK4 modification on blood pressure and related functions | References |
---|---|---|---|---|
In vivo studies of GRK4 modification or variants | ||||
GRK4 knockout | Knockout mice | Global knock mice | Decreases systolic and diastolic blood pressures | Wang et al., 2016 |
GRK4 siRNA | SHRs | Silencing renal GRK4 expression via UTMD-delivered GRK4 siRNA | Decreases blood pressure; increases sodium excretion and urine volume, reduces D1R phosphorylation and improves D1R-mediated sodium excretion; restores the adiponectin- or ETBR-mediated increase in sodium excretion | Huang et al., 2016; Yang et al., 2020; Zhang et al., 2020 |
GRK4 As-Odns | SHRs and WKY rats | Renal GRK4 depletion via the chronic renal cortical interstitial infusion of GRK4 As-Odns | Decreases D1R phosphorylation to a greater extent in SHRs than in WKY rats; increases sodium excretion and urine volume, attenuates the increase in arterial blood pressure with age, and decreases protein excretion in SHRs, but not WKY rats | Sanada et al., 2006; Yatabe et al., 2008 |
GRK4 and AT1R As-Odns | SHRs and WKY rats | Silencing both renal GRK4 and AT1R via intrarenal cortical infusion of both GRK4 and AT1R As-Odns | Decreases blood pressure and increases sodium excretion to a greater extent in SHRs than WKY rats; decreases circulating levels of renin, ang II, and aldosterone, reduces urine protein excretion and improves the GSI in SHRs and WKY rats; greater natriuresis and amelioration of hypertension in SHRs than the rats treated with either GRK4 or AT1R As-Odn | Yatabe et al., 2008 |
Overexpression of hGRK4γ142V | hGRK4γ WT and hGRK4γ 142 V transgenic mice | Global transgenic mice | Higher blood pressure and renal D1R phosphorylation, impaired D1R-mediated sodium excretion, increased renal AT1R expression and pressor response to Ang II in hGRK4γ 142 V transgenic mice than those in hGRK4γ WT transgenic mice; higher AT1R protein expression in the aorta of GRK4γ 142 V transgenic mice than hGRK4γ WT transgenic mice; hyperphosphorylation of renal ETBR and AdipoR1, impairment of ETBR or AdipoR1 function, less natriuresis and diuresis induced by endothelin or adiponectin in SHRs than WKY rats and GRK4γ 142 V transgenic mice than hGRK4γ WT transgenic mice | Felder et al., 2002; Yang et al., 2020; Wang et al., 2016; Wang et al., 2007; Zhang et al., 2020. |
Overexpression of hGRK4γ 486 V | hGRK4γ WT and hGRK4γ 486 V transgenic mice | Global transgenic mice | Impairs sodium excretion, increases renal oxidative stress, and increases blood pressure with high salt diet in hGRK4γ 486 V transgenic mice, relative to hGRK4γWT transgenic mice | Diao et al., 2017; Wang et al., 2006 |
Overexpression of hGRK4γ 65 L | hGRK4γ WT and hGRK4γ 65 L transgenic mice | Global transgenic mice | Increases blood pressure with high salt diet in hGRK4γ 65 L transgenic mice, relative to hGRK4γ WT transgenic mice | Asico and Jose, unpublished data |
In vitro studies of GRK4 modification or variants | ||||
Inhibition of GRK4 activity | RPT cells from normotensive humans | Treatment with heparin, an inhibitor of GRK activity | Decreases the expression of GRK2 and GRK4 and attenuates the desensitization of D1R, blunts p44/42 phosphorylation and mitogenesis induced by D3R stimulation in hRPTCs | Watanabe et al., 2002; Villar et al., 2009 |
Inhibition of GRK4 expression | RPT cells from hypertensive humans | Treatment with antibody recognizing GRK4γ/δ isoforms | Blocks the stimulatory effect of the D1-like receptor agonist, fenoldopam, on GRK activity | Felder et al., 2002 |
GRK4 As-Odns | RPT cells from hypertensive humans | GRK4 knockdown with its specific As-Odns | Blocks the D1R phosphorylation, blunts fenoldopam-induced D1R desensitization, and restores the D1-like receptor-mediated cAMP production | Felder et al., 2002 |
GRK4 siRNA | RPT cells from SHRs | GRK4 knockdown with its specific siRNA | Recovers the impaired inhibitory effect of ETBR on Na+/K+-ATPase activity | Yang et al., 2020 |
GRK4 siRNA | RPT cells from normotensive humans | RPT cells transfected with GRK4 siRNA | Blunts the D3R-mediated mitogenesis | Villar et al., 2009 |
Inhibition of GRK4 activity | Rat intestinal epithelial cells | Treatment with heparin, an inhibitor of GRK activity | Heparin prevents the loss of inhibition of NHE activity caused by 25 min exposure to SKF-38393, a D1-like receptor agonist | Fraga et al., 2004 |
Inhibition of GRK4 expression | Rat intestinal epithelial cells | Treatment with the anti-GRK4–6 antibody | Restores the loss of inhibition of NHE activity and stimulation of AC activity caused by 25 min exposure to SKF-38393, a D1-like agonist | Fraga et al., 2004 |
Overexpression of GRK4 variants | CHO cells | Transfected with GRK4γ with SNPs (A142V, R65L, A486V or combined R65L and A486V) | Increases basal D1R phosphorylation and impairs D1R-mediated cAMP accumulation | Felder et al., 2002 |
Overexpression of GRK4 splice variants | CHO cells | Transfected with GRK4α, GRK4β, GRK4γ or GRK4δ | GRK4γ and GRK4α increase the phosphorylation of D3R compared with untreated control cells; activation of D3R results in a 3-fold and 2-fold increase in D3R phosphorylation in cells expressing GRK4γ and GRK4α, respectively | Villar et al., 2009 |
Overexpression of hGRK4γ 142 V | RPT cells from normotensive humans | RPT cells transfected with hGRK4γ 142 V and GRK4γ WT plasmids | Increases activity of Agtr1 and AT1R protein expression | Wang et al., 2016 |
Overexpression of hGRK4γ 142 V | VSMCs | Transfected with hGRK4γ 142 V and GRK4γ WT plasmids | Higher AT1R protein and mRNA expressions, lower AT1R phosphorylation and protein degradation, higher AT1R-mediated intracellular calcium concentration after stimulation with Ang II in hGRK4γ 142 V than in GRK4γ WT cells | Chen et al., 2014 |
Overexpression of GRK4 | HEK293 cells | Transfected with full-length GRK4 plasmid | Induces cellular senescence, halts cell proliferation | Xiao et al., 2017; Luo et al., 2019 |
Abbreviations: AC, adenylyl cyclase; AdipoR1, adiponectin receptor 1; Ang II, angiotensin II; As-Odns, antisense oligodeoxynucleotides; AT1R, angiotensin II receptor type 1; cAMP, cyclic adenosine monophosphate; CHO, Chinese hamster ovary; D1R, dopamine D1 receptor; D3R, dopamine D3 receptor; ETBR, endothelin receptor type B; GRK4, G protein-coupled receptor kinase 4; GSI, glomerular sclerosis index; hRPTCs: human renal proximal tubules cells; NHE: sodium-hydrogen exchanger; RPT, renal proximal tubule; SHRs, spontaneously hypertensive rats; siRNA, small interfering RNA; UTMD, ultrasound-targeted microbubble destruction; VSMCs, vascular smooth muscle cells; WKY, Wistar-Kyoto; WT, wild-type.