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

肾盂肾炎继续导致相当大的发病率、死亡率和医疗费用。为了开发新的治疗策略，需要更彻底地了解肾脏在肾脏和尿路固有防御中的作用。 我们的研究已经确定了一种小鼠插层细胞缺陷模型，该模型易患肾盂肾炎。我们还证明了人和小鼠的嵌合细胞产生和分泌抗菌肽。其他人已经证明，间质细胞是肾脏中第一个通过模式识别受体信号通路对革兰氏阴性生物做出反应的部位。因此，更多的证据表明，嵌入细胞在肾脏的天然防御中发挥着关键作用。 在以前的研究中，我们对人肾脏进行了单细胞mRNA测序，发现“吞噬小体成熟”是插入细胞的关键途径。然后，我们开发了可视化细菌吞噬细菌的方法，并实时演示了这一功能。我们推测，插层细胞利用吞噬细菌的过程来调节酸碱平衡，这种吞噬作用在尿路感染期间可能会增强。我们知道嵌入细胞可以吞噬细菌。我们将使用实时成像技术(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-ATPase在插层细胞吞噬中的作用。 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，并在高危人群中保护肾功能。这项拟议的研究将为将插层细胞的调节纳入肾盂肾炎的治疗提供基础，从而扩大抗生素以外的治疗范围。

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.