Akhtar Md Naushad, Mishra Manish, Yadav Vinod, Yadav Manisha, Gujar Ravindra, Lal Sunaina, Kumar Raj, Khatri Neeraj, Sen Pradip
Division of Cell Biology and Immunology, Council of Scientific and Industrial Research- Institute of Microbial Technology, Chandigarh, India.
IMTECH-Centre for Animal Resources and Experimentation (iCARE), Council of Scientific and Industrial Research-Institute of Microbial Technology, Chandigarh, India.
PLoS Pathog. 2020 Dec 28;16(12):e1009136. doi: 10.1371/journal.ppat.1009136. eCollection 2020 Dec.
The level of CD40 expression on dendritic cells (DCs) plays a decisive role in disease protection during Leishmania donovani (LD) infection. However, current understanding of the molecular regulation of CD40 expression remains elusive. Using molecular, cellular and functional approaches, we identified a role for Runx1 and Runx3 transcription factors in the regulation of CD40 expression in DCs. In response to lipopolysaccharide (LPS), tumor necrosis factor alpha (TNFα) or antileishmanial drug sodium antimony gluconate (SAG), both Runx1 and Runx3 translocated to the nucleus, bound to the CD40 promoter and upregulated CD40 expression on DCs. These activities of Runx proteins were mediated by the upstream phosphatidylinositol 3-kinase (PI3K)-Akt pathway. Notably, LD infection attenuated LPS- or TNFα-induced CD40 expression in DCs by inhibiting PI3K-Akt-Runx axis via protein tyrosine phosphatase SHP-1. In contrast, CD40 expression induced by SAG was unaffected by LD infection, as SAG by blocking LD-induced SHP-1 activation potentiated PI3K-Akt signaling to drive Runx-mediated CD40 upregulation. Adoptive transfer experiments further showed that Runx1 and Runx3 play a pivotal role in eliciting antileishmanial immune response of SAG-treated DCs in vivo by promoting CD40-mediated type-1 T cell responses. Importantly, antimony-resistant LD suppressed SAG-induced CD40 upregulation on DCs by blocking the PI3K-Akt-Runx pathway through sustained SHP-1 activation. These findings unveil an immunoregulatory role for Runx proteins during LD infection.
树突状细胞（DCs）上CD40的表达水平在杜氏利什曼原虫（LD）感染期间的疾病保护中起决定性作用。然而，目前对CD40表达分子调控的理解仍然不清楚。通过分子、细胞和功能方法，我们确定了Runx1和Runx3转录因子在DCs中CD40表达调控中的作用。响应脂多糖（LPS）、肿瘤坏死因子α（TNFα）或抗利什曼原虫药物葡萄糖酸锑钠（SAG），Runx1和Runx3均易位至细胞核，与CD40启动子结合并上调DCs上的CD40表达。Runx蛋白的这些活性由上游磷脂酰肌醇3激酶（PI3K）-Akt途径介导。值得注意的是，LD感染通过蛋白酪氨酸磷酸酶SHP-1抑制PI3K-Akt-Runx轴，从而减弱DCs中LPS或TNFα诱导的CD40表达。相反，SAG诱导的CD40表达不受LD感染的影响，因为SAG通过阻断LD诱导的SHP-1激活增强PI3K-Akt信号传导，以驱动Runx介导的CD40上调。过继转移实验进一步表明，Runx1和Runx3通过促进CD40介导的1型T细胞反应，在体内引发SAG处理的DCs的抗利什曼原虫免疫反应中起关键作用。重要的是，抗锑LD通过持续激活SHP-1阻断PI3K-Akt-Runx途径，抑制DCs上SAG诱导的CD40上调。这些发现揭示了Runx蛋白在LD感染期间的免疫调节作用。
