Linking the microbiome and immune-checkpoint in melanoma by RNF5

项目摘要 该应用程序旨在定义一种控制肠道微生物的新机制-免疫检查点 泛素连接酶RNF 5的相互作用，以及这种调节对黑色素瘤发展的影响 和对治疗的反应尽管在临床管理方面取得了最令人兴奋和重大的进展， 黑色素瘤通过免疫检查点为基础的临床试验，其控制机制， 对不同疗法的敏感性（或不敏感）是尚未解决的基本问题之一。在这里， 我们提供的数据支持了一个模型，即免疫检查点受肠道微生物组的调节， 由泛素连接酶RNF 5定义。我们发现Braf/Pten突变型黑色素瘤的生长受损， 与同窝出生的Rnfwt小鼠相比，同基因Rnf 5-/-小鼠与增强的肿瘤浸润有关， 肿瘤中的浸润性淋巴细胞（TIL）（CD 4和CD 8阳性）、巨噬细胞和树突状细胞， 在Rnf 5-/-小鼠中发展明显较慢。引人注目的是，共同圈养Rnf 5-/-和Rnfwt动物或 肠道微生物群的抗生素消融导致上述表型的丧失-肿瘤生长不再是 减毒的和基于免疫检查点的表型大量丢失。肠道微生物组评估 揭示了细菌物种的不同子集，其将Rnf 5-/-小鼠与其WT同窝出生的小鼠区分开（所有 “纯的”内部维持的C57 BL/6菌株）。值得注意的是，不同RNF 5-微生物组的共同点是细菌 产生选择的短链脂肪酸子集的物种。这些观察为以下方面提供了基础： 我们假设RNF 5控制影响免疫检查点的肠道微生物群， 这反过来又会影响黑色素瘤的发展。我们建议的研究将（i）定义RNF 5 对肠道微生物组-肿瘤相互作用的影响，（ii）确定调节中的微生物组依赖性变化 肿瘤免疫检查点控制RNF 5，和（iii）建立生理意义和影响 RNF 5对不同小鼠品系、年龄和性别的黑色素瘤发生的微生物组和免疫检查点的控制 在选择的联合疗法下。我们高度综合的研究将确定基本机制， 作为肠道微生物组和免疫检查点调节的基础，从而为以下方面提供新的见解： 黑色素瘤和其他癌症的治疗方式。

Project Summary This application is set to define a novel mechanism underlying the control of gut microbiota-immune checkpoint interactions by the ubiquitin ligase RNF5, and the implications of such regulation to melanoma development and response to therapy. Despite the most exciting and significant advances made in clinical management of melanoma via the immune-checkpoint based clinical trials, mechanisms underlying their control, the susceptibility to distinct therapies (or not), are among the fundamental questions that remain unsolved. Here, we provide data to support a model whereby immune checkpoints are regulated by gut microbiome, which is defined by the ubiquitin ligase RNF5. Our discovery of impaired growth of Braf/Pten mutant melanoma in syngeneic Rnf5–/– mice, compared with Rnfwt littermates, was linked with enhanced infiltration of tumor- infiltrating lymphocytes (TILs) (CD4 and CD8 positive), macrophages and dendritic cells in the tumors that developed significantly slower in the Rnf5–/– mice. Strikingly, co-housing the Rnf5–/– and Rnfwt animals or antibiotic ablation of the gut microbiota resulted in loss of the above phenotypes—tumor growth was no longer attenuated and immune checkpoint-based phenotypes were largely lost. Assessment of the gut microbiome revealed a distinct subset of bacterial species, which distinguish Rnf5–/– mice from their WT littermates (all “pure” in-house maintained C57BL/6 strain). Notably, common to the distinct RNF5-microbiome are bacterial species that generate select subset of short chain fatty acids. These observations provide the foundation for our hypothesis that RNF5 controls the intestinal microbiota that affects immune checkpoint mechanisms, which in turn impacts melanoma development. Our proposed studies will (i) define RNF5 effect on the gut microbiome–tumor interactions, (ii) identify microbiome-dependent changes in the regulation of tumor immune checkpoint control by RNF5, and (iii) establish the physiological significance and impact of RNF5 control of microbiome and immune checkpoint on melanomagenesis in different mouse strains, age, and under select combination therapies. Our highly integrated studies will define the fundamental mechanisms that underlie the regulation of both gut microbiome and immune checkpoints, thereby providing new insights into therapeutic modalities for melanoma and other cancers.