Vitamin D Metabolism in Leprosy

维生素D在麻风分枝杆菌（mLEP）的发病机制和治疗中的作用已被假定多年。患有进行性、杆菌丰富型麻风瘤（L-lep）的患者更可能缺乏维生素D，临床上可从紫外线B（阳光）照射或饮食补充维生素D中获益。这样的患者还处于疾病激活的巨噬细胞从循环25-羟基维生素D（25 D）过度产生活性维生素D代谢物1，25-二羟基维生素D（1，25 D）的失调的风险中。另一方面，在维生素D受体（VDR）水平上的细胞内1，25 D合成和作用对于对mLEP产生抗微生物应答至关重要。因此，控制麻风病中维生素D代谢和作用的机制是该病的关键组成部分。我们最近的体外研究清楚地证明了维生素D系统的功能元件的差异表达，包括CYP 27 B1-羟化酶和VDR分别在I型和II型干扰素驱动的T-lep和L-lep肉芽肿中。总之，这些临床和实验室发现使我们推测，mLEP感染和相应的T-lep或L-lep下游干扰素导向途径将不同地影响麻风宿主感染微环境中巨噬细胞和其他引发的表达VDR的炎性细胞中活性维生素D代谢物的合成、代谢和功能。为了检验这一假设，我们将进行三个概念新颖的，机械的目标。首先，将在单细胞水平上定量绘制T-lep和L-lep肉芽肿中的维生素D系统组分（CYP 2 R1，维生素D羟化酶; CYP 27 B1; CYP 24 A1，24-羟化酶;和VDR）。第二，T-lep或L-lep免疫应答分泌体以及相关的下游干扰素应答对人体炎症细胞中维生素D代谢和免疫作用的协调作用将使用项目1和3中开发的创新分子工具进行表征。第三，使用最近构思的RNA测序技术，将探讨人类宿主维生素D缺乏状态的功能后果，以及其在体外和体内对mLEP的免疫应答和杀伤的拯救。当与其他CORT项目的实验结果一起分析时，预计这项工作将为操纵人类维生素D平衡的实践奠定基础，以促进麻风病特异性和肉芽肿形成疾病的先天性和适应性免疫反应。

A role for vitamin D in the pathogenesis and treatment of Mycobacterium leprae (mLEP) has been presumed for many years. Pafients suffering from the progressive, bacilli-abundant lepromatous form (L-lep) ofthe disease are more likely to be vitamin D-deficient and benefit clinically from ultraviolet B (sunlight) irradiation or dietary supplementation vitamin D. Such patients are also at risk for developing dysregulated over- production of the active vitamin D metabolite 1,25-dihydroxyvitamin D (1,25D) from circulating 25- hydroxyvitamin D (25D) by disease-activated macrophages. On the other hand, intracellular 1,25D synthesis and action at the level of the vitamin D receptor (VDR) is crucial for mounting an antimicrobial response to mLEP. Therefore, the mechanism(s) that govern vitamin D metabolism and action in leprosy is a key component to the disease. Our recent studies In vitro clearly demonstrate the differential expression of the functional elements ofthe vitamin D system, including CYP27B1-hydroxylase and the VDR in Type I and II interferon-driven, T-lep and L-lep granulomas, respectively. Taken together, these clinical and laboratory findings lead us to theorize that mLEP Infection and the respective T-lep or L-lep downstream interferon- directed pathways, will differentially Impact the synthesis, metabolism and function of active vitamin D metabolites in the macrophage and other elicited, VDR-expressing inflammatory cells in the infectious microenvironment ofthe host with leprosy. To test this hypothesis, we will undertake three conceptually novel, mechanistic aims. First, the vitamin D system components (CYP2R1, vitamin D hydroxylase; CYP27B1; CYP24A1, 24-hydroxylase; and VDR) will be quantitatively mapped in T-lep and L-lep granulomas at the single cell level. Second, the orchestrated effects of T-lep or L-lep immune response secretomes, and associated downstream interferon responses, on the metabolism and immunoaction of vitamin D in human inflammatory cells will be characterized using innovative molecular tools developed in Projects 1 and 3. Third, using recently-conceived RNA sequencing technologies, the functional consequences ofthe human host vitamin D deficient state, and its rescue In vitro and in vivo, on immune responses to and killing of mLEP will be probed. When analyzed in concert with the experimental results of the other CORT projects, it is anticipated that this work will set the stage for the practice of manipulating human vitamin D balance in promotion ofthe innate and adaptive immune response in leprosy specifically and in granuloma-forming diseases in general.