Salt Mediated Cross Talk Between Lymphatic Vessels and Immune Cells in Kidney Disease

总结 淋巴管对于维持间质液稳态、免疫细胞运输和抗原表达至关重要。 间隙由于淋巴转运不足导致的无效清除是许多疾病的关键促进因素， 反映了淋巴管网络的数量、重吸收能力和收缩力不足。相比之下 对于血管，淋巴管对间质元素非常敏感，包括Na+， 在高血压环境中淋巴生长的强大调节剂。我们在高血压环境中的研究发现， Na+激活抗原呈递免疫中的高反应性脂质氧化产物异乌藨子素（IsoLG） 细胞（APC）通过上皮Na+通道（ENaC）。我们的新数据显示，蛋白尿肾病增加 肾内Na+，从而在肾实质内建立高Na+环境。就像免疫系统中的ENaC 细胞，Na+，而不是渗透压，调节钠钾氯化物协同转运蛋白（NKCC 1）的表达， 淋巴管内皮细胞（LECs）。蛋白尿动物和人类的尿IsoLG水平升高 加合至载脂蛋白AI（apoAI），以其在炎症、氧化应激和胆固醇中的作用而闻名 动脉粥样硬化性心脏病的治疗尽管肾脏疾病表现出与改良的 apoAI，关于这些对肾脏的影响知之甚少。我们首次发现肾损伤会促进 肾内IsoLG和IsoLG-apoAI上调LEC中NKCC 1。我们已经公布的和初步的 数据支持肾损伤导致肾Na+蓄积的假设， 淋巴管生成，激活LEC，削弱淋巴动力，促进免疫细胞 通过NKCC 1和IsoLG的Na+感知机制运输到肾皮质 通过LEC。我们的研究将确定肾内Na+蓄积如何调节淋巴网络， 我们假设肾组织化学和激活的免疫细胞之间的相互作用促进了间质停滞 潜在的有害分子和细胞以及随后的肾小管间质纤维化。为了验证这个假设，我们 提出三个机械化目标。目的1将检验损伤驱动的Na+在肾组织中蓄积的假设， 氚通过IsoLG-NKCC 1直接破坏肾淋巴网络的结构和功能 通路目的2将定义Na+激活的免疫细胞如何涉及IsoLG和血管收缩内皮素， 损害肾组织，从而增加肾间质停滞。在目标3中，我们将确定激活 来自CKD患者的具有高IsoLG的单核细胞使淋巴管生成变钝并减弱淋巴泵 在人源化小鼠中促进进行性肾纤维化。

SUMMARY Lymphatic vessels are essential to maintaining interstitial fluid homeostasis, immune cell trafficking and antigen clearance. Ineffectual clearance due to inadequate lymphatic transport is a key promoter of many diseases that reflects insufficient number, reabsorptive capacity and contractility of the lymphatic vascular network. In contrast to blood vessels, lymphatic vessels are exquisitely sensitive to interstitial elements, including Na+ which is a powerful regulator of lymphatic growth in hypertensive settings. Our studies in hypertensive settings, have found Na+ activates the highly reactive lipid oxidation product, isolevuglandin (IsoLG) in antigen presenting immune cells (APCs) via the epithelial Na+ channel (ENaC). Our new data reveal proteinuric kidney disease increases intrarenal Na+ and thus establish a high Na+ environment within the kidney parenchyma. Like ENaC in immune cells, Na+, not osmolality, modulates expression of the sodium potassium chloride co-transporter (NKCC1) in lymphatic endothelial cells (LECs). Proteinuric animals as well as humans have elevated levels of urinary IsoLG adducted to apolipoprotein AI (apoAI) best known for its role in inflammation, oxidative stress, and cholesterol handling in atherosclerotic heart disease. Although kidney disease manifests all co-morbidities linked to modified apoAI, little is understood about these effects on kidneys. We show for the first time that kidney injury promotes intrarenal IsoLG and that IsoLG-apoAI upregulates NKCC1 in LECs. Together, our published and preliminary data support the hypothesis that kidney injury leads to renal Na+ accumulation which stimulates lymphangiogenesis, activates LECs, weakens lymphatic dynamics that encourages immune cell trafficking into the renal interstitium through mechanisms that involve Na+ sensing via NKCC1 and IsoLG uptake by LECs. Our studies will define how intrarenal Na+ accumulation modulates the lymphatic network and crosstalk between renal lymphatics and activated immune cells which we postulate promote interstitial stagnation of potentially harmful molecules and cells and subsequent tubulointerstitial fibrosis. To test this hypothesis, we propose three mechanistic aims. Aim 1 will test the hypothesis that that injury-driven accumulation of Na+ in renal interstitium directly disrupts the structure and function of the renal lymphatic network via a IsoLG-NKCC1 pathway. Aim 2 will define how Na+ activated immune cells involve IsoLG and vasoconstricting endothelins to impair renal lymphatics thereby increasing renal interstitial stagnation. In Aim 3 we will determine that activated monocytes with high IsoLG from humans with CKD blunt lymphangiogenesis and weaken lymphatic pumping that promotes progressive kidney fibrosis in humanized mice.