Anti-nociceptive actions of CART II in chemotherapy-induced peripheral neuropathy

项目总结 近70%接受抗肿瘤药物治疗的患者出现化疗所致的周围神经病变(CIPN) 肿瘤药物并在停止治疗后持续存在，从而影响患者的生活质量。反- 镇静剂度洛西汀(5-羟色胺和去甲肾上腺素摄取的选择性抑制剂)缓解疼痛的效果有限，而 长期使用阿片类药物治疗慢性疼痛存在安全风险。因此，需要新型非阿片类镇痛剂来治疗 癌症患者的疼痛管理。我们的发现表明，脊椎上(大脑)递送可卡因和 苯丙胺调节转录肽II(CART II)逆转男性和女性的痛样行为(触觉) 感染CIPN的小鼠。多个行为输出将提供临床表面有效性，并增强可译性 给定靶点，从而全面评估CART II在慢性疼痛中的抗痛觉过敏效果 在两性慢性疼痛的多个终点处，两性的CART II状态是有根据的。以前的研究 已经发现了CART II的更广泛的药理作用和神经肽的全身给药 可能会带来挑战，因此确定CART II的神经化学信号机制至关重要 在CIPN中。虽然缺乏已知的CART II受体阻碍了这种机制研究，但我们发现 溶血磷脂酸受体2(LPAR2)是脑内CART II的高亲和力受体。我们用手机- 基于分析和体内药理学工具显示脊髓上LPAR2是CART II诱导的必需的 急性止痛。然而，LPAR2在慢性疼痛状态中的作用尚未得到评估。我们的发现还包括 证明治疗剂量的脊髓上CART II增加腹外侧区谷氨酸的释放 幼稚小鼠中脑导水管周围灰质(VlPAG)和伏隔核(NAcc)，以前的工作显示兴奋 对这些大脑部位的输入可以缓解神经病理性疼痛状态。然而，CIPN期间的神经传递在 VlPAG和NAcc尚未完全建立。这一提议的中心假设是CART II产生了 其抗痛敏作用是通过激活LPAR2和增加谷氨酸释放来实现的。因此，我们建议充分 研究这一信号通路在vlPAG和NAcc中的抗痛觉过敏作用 独立但又相互关联的目标。目标1将综合评价剂量依赖的抗痛觉过敏药物 棘上CART II在4种不同行为输出指标(触觉、冷感、焦虑、抑郁)中的作用 询问CIPN治疗潜力的性别差异。正变构调节剂的掺入 基因敲除的小鼠将揭示LPAR2是否是CART II抗痛敏作用的必要条件和充分条件。 目的2将研究CART II介导的神经传递作为其抗痛觉过敏的作用机制 对CIPN的影响。总体而言，预期成果将解决对 神经病理性疼痛状态下的脊髓上机制和作为一个新的询问CART II/LPAR2轴 逆转已建立的CIPN的治疗策略。

PROJECT SUMMARY Chemotherapy-induced peripheral neuropathy (CIPN) manifests in nearly 70% of patients treated with anti- neoplastic drugs and persists after treatment discontinuation, thereby impacting patient quality of life. The anti- depressant duloxetine (selective inhibitor of serotonin and norepinephrine uptake) offers limited pain relief, while long-term use of opioids for chronic pain carries safety risks. Thus, novel non-opioid analgesics are needed for pain management in cancer patients. Our findings show that supraspinal (in the brain) delivery of cocaine and amphetamine-regulated transcript peptide II (CART II) reverses pain-like behaviors (tactile) in male and female mice with CIPN. Multiple behavioral outputs would provide clinical face validity and bolster translatability of a given target, thus a comprehensive dose-evaluation of CART II anti-hyperalgesic effects during chronic pain states of CART II in both sexes at multiple endpoints of chronic pain in both sexes is warranted. Previous studies have uncovered broader pharmacological actions of CART II and systemic administration of a neuropeptide likely will impose a challenge, so it is critical to determine the neurochemical signaling mechanisms of CART II in CIPN. While the lack of a known receptor for CART II has prevented such mechanistic studies, we discovered that Lysophosphatidic Acid Receptor 2 (LPAR2) is a high affinity receptor for CART II in the brain. We used cell- based assays and in vivo pharmacology tools to show that supraspinal LPAR2 is necessary CART II-induced acute analgesia. However, the role of LPAR2 in chronic pain states has not been evaluated. Our findings also demonstrate that therapeutic doses of supraspinal CART II increase glutamate release in ventrolateral periaqueductal gray (vlPAG) and nucleus accumbens (NAcc) in naïve mice, and previous work shows excitatory inputs into these brain sites can relieve neuropathic pain states. However, neurotransmission during CIPN in the vlPAG and NAcc has not been fully established. The central hypothesis in this proposal is that CART II produces its anti-hyperalgesic effects via activation of LPAR2 and increased glutamate release. Thus, we propose to fully examine anti-hyperalgesic actions of this signaling pathway in vlPAG and NAcc in males and females via two independent yet interconnected aims. Aim 1 will comprehensively evaluate dose-dependent anti-hyperalgesic effects of supraspinal CART II in 4 different behavioral output measures (tactile, cold, anxiety, depression) to interrogate any sex differences in therapeutic potential for CIPN. Incorporation of a positive allosteric modulator and knockout mice will reveal if LPAR2 is necessary and sufficient for the anti-hyperalgesic actions of CART II. Aim 2 will examine CART II-mediated neurotransmission as a mechanism of action for its anti-hyperalgesic effects in CIPN. Collectively, the expected results will address significant gaps in understanding of the supraspinal mechanisms underlying neuropathic pain states and interrogate the CART II/LPAR2 axis as a novel therapeutic strategy in reversing already established CIPN.