1.
Two Liters a Day Keep the Doctor Away? Considerations on the Pathophysiology of Suboptimal Fluid Intake in the Common Population.
Lang, F, Guelinckx, I, Lemetais, G, Melander, O
Kidney & blood pressure research. 2017;(3):483-494
Abstract
Suboptimal fluid intake may require enhanced release of antidiuretic hormone (ADH) or vasopressin for the maintenance of adequate hydration. Enhanced copeptin levels (reflecting enhanced vasopressin levels) in 25% of the common population are associated with enhanced risk of metabolic syndrome with abdominal obesity, type 2 diabetes, hypertension, coronary artery disease, heart failure, vascular dementia, cognitive impairment, microalbuminuria, chronic kidney disease, inflammatory bowel disease, cancer, and premature mortality. Vasopressin stimulates the release of glucocorticoids which in turn up-regulate the serum- and glucocorticoid-inducible kinase 1 (SGK1). Moreover, dehydration upregulates the transcription factor NFAT5, which in turn stimulates SGK1 expression. SGK1 is activated by insulin, growth factors and oxidative stress via phosphatidylinositide-3-kinase, 3-phosphoinositide-dependent kinase PDK1 and mTOR. SGK1 is a powerful stimulator of Na+/K+-ATPase, carriers (e.g. the Na+,K+,2Cl- cotransporter NKCC, the NaCl cotransporter NCC, the Na+/H+ exchanger NHE3, and the Na+ coupled glucose transporter SGLT1), and ion channels (e.g. the epithelial Na+ channel ENaC, the Ca2+ release activated Ca2+ channel Orai1 with its stimulator STIM1, and diverse K+ channels). SGK1 further participates in the regulation of the transcription factors nuclear factor kappa-B NFκB, p53, cAMP responsive element binding protein (CREB), activator protein-1, and forkhead transcription factor FKHR-L1 (FOXO3a). Enhanced SGK1 activity fosters the development of hypertension, obesity, diabetes, thrombosis, stroke, inflammation including inflammatory bowel disease and autoimmune disease, cardiac fibrosis, proteinuria, renal failure as well as tumor growth. The present brief review makes the case that suboptimal fluid intake in the common population may enhance vasopressin and glucocorticoid levels thus up-regulating SGK1 expression and favouring the development of SGK1 related pathologies.
2.
[WNK-SPAK-SLC12A signal cascade is a new therapeutic target for hypertension].
Kikuchi, E, Mori, T, Uchida, S
Nihon rinsho. Japanese journal of clinical medicine. 2015;(9):1597-605
Abstract
WNK-oxidative stress-responsive 1 (OSR1) /STE20/SPS1-related proline-alanine-rich protein kinase(SPAK)-SLC12A transporters cascade regulates blood pressure through NaCl reabsorption in kidney and vasoconstriction. Furthermore, we recently reported that this cascade is positively regulated by insulin, which may contribute to hypertension in patients with hyperinsulinemia. Therefore, drugs that inhibit this signal cascade could become new antihypertensive drugs that have dual effects as a diuretic and vasodilator and be particularly beneficial for patients with hyperinsulinemia such as metabolic syndrome and obesity. In this review, we provide an overview about the current understanding about WNK-SPAK-SLC12A signal cascade and show some prospects for drug discovery that blocks this signal cascade.
3.
Advances in WNK signaling of salt and potassium metabolism: clinical implications.
Arroyo, JP, Gamba, G
American journal of nephrology. 2012;(4):379-86
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Abstract
Recent evidence due to the discovery of a family of kinases implicated in arterial hypertension now points to the underlying molecular mechanisms that dictate Na(+), K(+) and water handling in the nephron. These new key players need to be understood in order to fully comprehend the pathophysiology, manifestations, and treatment of common clinical entities such as hypovolemic shock, congestive heart failure, primary hyperaldosteronism, nephrotic syndrome and hypertension. It is through the analysis of the volume status and electrolyte abnormalities that commonly present with these diseases that we can begin to create a link between the abstract concept of a kinase regulation and how a patient will respond to a particular treatment. This review is an attempt to bridge that gap.
4.
The long and winding road to rational treatment of cancer associated with LKB1/AMPK/TSC/mTORC1 signaling.
van Veelen, W, Korsse, SE, van de Laar, L, Peppelenbosch, MP
Oncogene. 2011;(20):2289-303
Abstract
The liver kinase B1 (LKB1)/adenosine mono-phosphate-activated protein kinase (AMPK)/tuberous sclerosis complex (TSC)/mammalian target of rapamycin (mTOR) complex (mTORC1) cassette constitutes a canonical signaling pathway that integrates information on the metabolic and nutrient status and translates this into regulation of cell growth. Alterations in this pathway are associated with a wide variety of cancers and hereditary hamartoma syndromes, diseases in which hyperactivation of mTORC1 has been described. Specific mTORC1 inhibitors have been developed for clinical use, and these drugs have been anticipated to provide efficient treatment for these diseases. In the present review, we provide an overview of the metabolic LKB1/AMPK/TSC/mTORC1 pathway, describe how its aberrant signaling associates with cancer development, and indicate the difficulties encountered when biochemical data are extrapolated to provide avenues for rational treatment of disease when targeting this signaling pathway. A careful examination of preclinical and clinical studies performed with rapamycin or derivatives thereof shows that although results are encouraging, we are only half way in the long and winding road to design rationale treatment targeted at the LKB1/AMPK/TSC/mTORC1 pathway. Inherited cancer syndromes associated with this pathway such as the Peutz-Jeghers syndrome and TSC, provide perfect models to study the relationship between genetics and disease phenotype, and to delineate the complexities that underlie translation of biochemical and genetical information to clinical management, and thus provide important clues for devising novel rational medicine for cancerous diseases in general.