The Role of Canonical and Non-canonical Autophagy in B Cell Immunity

B细胞在人类健康中发挥着核心作用，它通过产生 高亲和力抗体和能够进行抗原召回的长寿命记忆细胞。B细胞函数的摄动 不仅会导致抵抗感染的能力降低和疫苗接种无效，而且还会导致以下情况 白血病和自身免疫性疾病。因此，了解有助于 最佳的B细胞功能对于新疗法和疫苗接种策略的产生是极其重要的。 这项提议的主要目标是研究自噬，一种溶酶体的降解途径，有许多 生理和病理生理作用，塑造B细胞免疫反应。规范的归纳法 自噬通常需要下调生物合成的激酶mTORC1。然而，在B细胞中， BCR刺激自噬和mTORC1活性同时上调，提示B细胞 自噬很可能是mTORC1独立的。我们的实验室最近表明，从基本的 在幼稚、抗原缺乏经验的B细胞中典型的自噬为非常规的、mTORC1非依赖的、非 生发中心(GC)B细胞在抗原刺激下的典型活性。GCS是决定因素 高亲和力、类别转换的抗体产生，因此对驱动这些抗体的机制的研究 高质量的免疫反应在开发下一代疫苗、治疗性疫苗方面至关重要 单抗和自身免疫性疾病的治疗。 我们的工作假设是，非典型自噬在B细胞增殖过程中很重要，并将 与影响抗体质量的GC生物学有关，而规范的自噬对于长期记忆是重要的 影响抗体持久性的细胞和浆细胞。为了验证这一假设，我们将评估GC和长期 携带已知影响平衡的新自噬基因遗传消融的小鼠的免疫反应 在典型自噬和非典型自噬之间，即Wipi1、Wipi2和Rubcon。我们还将确定 这些基因的缺失影响抗原呈递和激发T细胞帮助的机制。最后， 因为自噬与线粒体的完整性和新陈代谢相交，我们将确定这些基因是如何 缺失控制GC B细胞、记忆和浆细胞调节ROS产生、线粒体的能力 动态平衡和代谢状态，并可能影响B细胞的命运。 我们设想，成功完成这些实验目标不仅将提供更好的 对B细胞功能的理解，以及对如何调节自噬以影响体液的机械性见解 免疫-在免疫衰老等情况下增强免疫，或在自身免疫情况下下调免疫 疾病。

B cells play a central role in human health by protecting us against infections through their ability to produce high-affinity antibodies and long-lived memory cells capable of antigenic recall. Perturbations in B cell function can not only lead to lowered ability to fight infections and inefficacy of vaccinations, but also to conditions such as leukemia, and autoimmune diseases. Thus, understanding the molecular mechanisms that contribute to optimal B cell function is extremely important for the generation of new therapeutics and vaccination strategies. The major goal of this proposal is to study how autophagy, a lysosomal degradative pathway with numerous physiological and pathophysiological roles, shapes B cell immunoresponses. The induction of canonical autophagy typically requires the downregulation of the biosynthetic kinase, mTORC1. However, in B cells upon BCR stimulation both autophagy and mTORC1 activity are simultaneously upregulated, suggesting that B cell autophagy is likely to be mTORC1 independent. Our lab has recently shown that there is a switch from basal canonical autophagy in naïve, antigen-inexperienced B cells to an unconventional, mTORC1-independent, non- canonical activity in the germinal center (GC) B cells upon antigenic stimulation. GCs are the determinants of high affinity, class switched antibody generation, and therefore the study of the mechanisms that drive these high-quality immunoresponses is vitally important in the development of next-generation vaccines, therapeutic monoclonal antibodies and in the treatment of autoimmune diseases. Our working hypothesis is that non-canonical autophagy is important during B cell proliferation and will be relevant to GC biology affecting antibody quality, while canonical autophagy is important for long-lived memory cells and plasma cells influencing antibody durability. To test this hypothesis, we will evaluate GC and long-term immune responses in mice bearing genetic ablations of novel autophagy genes that we know affect the balance between canonical and non-canonical autophagy, namely Wipi1, Wipi2 and Rubicon. We will also determine the mechanisms by which the deletions of these genes affect antigen presentation and in eliciting T cell help. Finally, because autophagy intersects with mitochondrial integrity and metabolism, we will determine how these gene deletions control the capacity of GC B cells, memory and plasma cells to regulate ROS production, mitochondrial homeostasis and metabolic status and potentially influence B cell fate. We envision that the successful completion of these experimental aims will not only provide a better understanding of B cell function, but also mechanistic insights into how to modulate autophagy to affect humoral immunity – augment it in cases such as immunosenescence, or downregulate it in instances of autoimmune diseases.