Sang Xiaohong, Jiao Haizhan, Meng Qian, Fang Xiong, Sundaram Kartik S, Zhou Jiao, Xu Yan, Alvarado Asuka I W, Nuryyev Ruslan L, Ourenik Jitka, Ourednik Vaclav, Huang Iris S, Liu Xiang, Mei Yuheng, Qian Tingli, Ciechanover Aaron, Pizzo Donald P, Lane Michael A, Zholudeva Lyandysha V, An Jing, Snyder Evan Y, Hu Hongli, Huang Ziwei
Ciechanover Institute of Precision and Regenerative Medicine, School of Medicine, The Chinese University of Hong Kong, Shenzhen 518172, China.
Kobilka Institute of Innovative Drug Discovery, School of Medicine, The Chinese University of Hong Kong, Shenzhen 518172, China.
bioRxiv. 2025 Jul 11:2025.07.08.663251. doi: 10.1101/2025.07.08.663251.
G-protein coupled receptors (GPCRs) are transmembrane proteins that mediate a range of signaling functions and, therefore, offer targets for a number of therapeutic interventions. Chemokine receptor CXCR4, a GPCR, plays versatile roles in normal and abnormal physiological processes. Synthetic CXCR4 antagonists have been extensively studied and approved for the clinical treatment of cancer and other diseases. We recently elucidated the structural mechanisms underlying CXCR4 antagonism using cryogenic electron microscopy (cryo-EM). CXCR4 agonism by synthetic molecules is an unanticipated therapeutic intervention we recently unveiled. The structural mechanisms underlying those actions remain poorly understood yet could help elucidate a new class of drugs. Here we demonstrate a synthetic dual-moiety strategy that combines simplified agonistic and antagonistic moieties taken from natural agonistic and antagonistic chemokines, respectively, to design de novo peptide mimics of biological function of natural CXCR4 agonist SDF-1α. Two peptides so generated, SDV1a and SDVX1 were shown to mimic the action of SDF-1α in activating CXCR4 signaling pathways and cell migration. The structural mechanism of these peptides in the mimicry of CXCR4 agonism was illustrated by cryo-EM structures of CXCR4 bound and activated by the peptides in the presence of G protein, revealing common interactions with the receptor by these peptides in comparison with SDF-1α that explain their close mimicry and conformational changes leading to CXCR4 signal activation. The therapeutic benefit of one of these peptides, SDV1a, was demonstrated in the SOD1 mouse model of the spinal motor neuron degenerative disease, amyotrophic lateral sclerosis (ALS) wherein the success of neuroprotective actions of transplanted human neural stem cells (hNSCs) is directly correlated with the expanse of diseased neuroaxis traversed by the donor cells; SDV1a enabled broader neuroprotective coverage while also permitting a much less invasive route of cell administration for extending life. Taken together, these results provide insights into the structural determinants of therapeutic CXCR4 agonism which may allow the design of adjunctive drugs that improve cell-based treatments of central nervous system (CNS) diseases.
G蛋白偶联受体（GPCRs）是介导一系列信号功能的跨膜蛋白，因此为多种治疗干预提供了靶点。趋化因子受体CXCR4作为一种GPCR，在正常和异常生理过程中发挥着多种作用。合成的CXCR4拮抗剂已得到广泛研究，并被批准用于癌症和其他疾病的临床治疗。我们最近利用低温电子显微镜（cryo-EM）阐明了CXCR4拮抗作用的结构机制。合成分子对CXCR4的激动作用是我们最近发现的一种意外的治疗干预措施。这些作用的结构机制仍知之甚少，但可能有助于阐明一类新型药物。在此，我们展示了一种合成双部分策略，该策略分别结合了取自天然激动性和拮抗性趋化因子的简化激动和拮抗部分，以从头设计天然CXCR4激动剂SDF-1α生物功能的肽模拟物。所产生的两种肽SDV1a和SDVX1被证明可模拟SDF-1α激活CXCR4信号通路和细胞迁移的作用。通过在G蛋白存在下肽与CXCR4结合并激活后的cryo-EM结构，阐明了这些肽模拟CXCR4激动作用的结构机制，揭示了与SDF-1α相比这些肽与受体的共同相互作用，解释了它们的紧密模拟以及导致CXCR4信号激活的构象变化。其中一种肽SDV1a在脊髓运动神经元退行性疾病肌萎缩侧索硬化症（ALS）的SOD1小鼠模型中显示出治疗益处，在该模型中，移植的人类神经干细胞（hNSCs）神经保护作用的成功与供体细胞穿越的患病神经轴范围直接相关；SDV1a实现了更广泛的神经保护覆盖，同时还允许采用侵入性小得多的细胞给药途径来延长寿命。综上所述，这些结果为治疗性CXCR4激动作用的结构决定因素提供了见解，这可能有助于设计辅助药物，改善中枢神经系统（CNS）疾病的细胞治疗。
