Control of Renal Inflammation in Hypertension

PROJECT SUMMARY By 2025, an estimated 1.6 billion people around the world will be hypertensive. This estimate may be higher given recently modified guidelines for hypertension that are inclusive of millions of additional patients. What is concerning is that almost 20% of all hypertensive patients are resistant to current therapies. Better understanding of the underlying mechanisms involved in the pathogenesis of hypertension is required in order to identify new and effective therapeutic strategies. Chronic renal inflammation is suspected to be a causal mechanism of resistant hypertension. The objective of this grant proposal is to examine the the control of renal inflammation using a model of chronic inflammatory disease. Systemic lupus erythematosus (SLE) is a chronic autoimmune inflammatory in which renal inflammation precedes the development of hypertension in SLE; therefore, it is an appropriate disease model to use to elucidate mechanisms involved in the inflammatory origins of hypertension. Endogenous neuro-immunoregulatory systems like the novel cholinergic anti-inflammatory pathway are involved in the normal control of excessive inflammation. Our data indicate that boosting this vagus nerve-to-spleen pathway via systemic pharmacological approaches reduces renal inflammation and blood pressure in an experimental mouse model of SLE. Based on this, we hypothesize that active neuroimmune pathways protect the kidney by suppressing renal inflammation and preventing the subsequent development of hypertension. In Aim 1 of this proposal, we will determine if central stimulation of the vagus nerve via both chemogenetic and pharmacological techniques reduces renal inflammation through the cholinergic anti- inflammatory pathway, and is antihypertensive in SLE. Studies in this aim will elucidate central nuclei involved in the regulation of renal inflammation that if left unchecked can result in hypertension in SLE. In Aim 2, we will determine whether inhibiting the cholinergic anti-inflammatory pathway by blocking its nodes of neurotransmission exacerbates SLE hypertension. Studies in this aim will determine critical neural/peripheral components necessary for proper neuroimmune regulation. In Aim 3, we will determine if an intrinsic renal anti- inflammatory pathway works in parallel with the spleen-centric cholinergic anti-inflammatory pathway. Studies in this aim will examine the anti-inflammatory potential of local acetylcholine in renal immune cells in hypertension- prone SLE mice using in vitro studies and innovative sniffer cell technoogy. Overall, the proposed studies will explain how homeostatic neuroimmune mechanisms control renal inflammation in health, as well as offer therapeutic options for controlling renal inflammation in hypertension and other chronic inflammatory diseases.