Harnessing the acid-base cellular machinery of intercalated cells in the bacterial defense of the kidney

肾盂肾炎持续导致相当大的发病率、死亡率和卫生保健费用。 为了开发新的治疗策略，需要更深入地了解肾脏在肾脏和泌尿道先天防御中的作用。 我们的研究已经确定了一个小鼠闰细胞缺陷模型，是易感肾盂肾炎。我们还证明了人类和小鼠的嵌入细胞产生和分泌抗菌肽。其他人已经证明，嵌入细胞作为肾脏中的第一个位点，通过模式识别受体信号通路对革兰氏阴性生物体做出反应。因此，大量证据表明，闰细胞在肾脏的先天防御中起着关键作用。 在先前的研究中，我们在用致尿病性大肠杆菌刺激后对人肾脏进行了单细胞mRNA测序。杆菌 “吞噬体成熟”是一个关键的插入细胞途径。然后，我们开发了可视化细菌吞噬细菌的方法，并实时演示了这种功能。我们推测，闰细胞采用的过程来吞噬细菌，他们利用调节酸碱平衡，这种吞噬作用可能会在UTI增强。我们知道闰细胞可以吞噬细菌。我们将使用活体小鼠真实的时间成像（Aim 1a）、互补流式细胞术研究（Aim 1b）和肾盂肾炎易感性研究（Aim 1c）来探索碳酸酐酶和V-ATP酶在嵌入细胞吞噬中的作用。 我们的长期研究目标是开发新的肾盂肾炎治疗策略，减少抗生素暴露，保护高危人群的肾功能。拟议的研究将提供基础，包括在肾盂肾炎管理的闰细胞的调制，从而扩大治疗范围超越抗生素。

Pyelonephritis continues to result in considerable morbidity, mortality and health care expense.  To develop new treatment strategies, a more thorough understanding of the kidney’s role in the innate defense of the kidney and urinary tract is needed.  Our research has identified a murine intercalated cell deficiency model that is susceptible to pyelonephritis. We have also demonstrated that human and murine intercalated cells produce and secrete antimicrobial peptides. Others have demonstrated that intercalated cells act as the first site in the kidney that responds to Gram-negative organisms via pattern recognition receptor signaling pathways. Thus, surmounting evidence suggests that intercalated cells perform a critical role in the innate defense of the kidney.  In prior studies we performed single cell mRNA sequencing on human kidneys following stimulation with uropathogenic E. coli.  “Phagosome maturation” was a key intercalated cell pathway. We then developed methodology to visualize bacteria phagocytosing bacteria and demonstrated this function in real-time. We hypothesize that intercalated cells employ the processes to phagocytose bacteria that they utilize to regulate acid-base balance and that this phagocytosis may be enhanced during UTI. We know that intercalated cells can phagocytose bacteria. We will explore the role of carbonic anhydrase and V-ATPase in intercalated cell phagocytosis using real time imaging in live mice (Aim 1a), complementary flow cytometry studies (Aim 1b) and on pyelonephritis susceptibility (Aim 1c)  Our long-term research goal is to develop new pyelonephritis treatment strategies that reduce antibiotic exposure and preserve renal function in populations at risk. The proposed research will provide the foundation to include modulation of intercalated cells in pyelonephritis management, thereby expanding treatment scope beyond antibiotics.