Deptartmen of Neural and Pain Sciences, University of Maryland School of Dentistry, Baltimore, MD, United States.
UM Center to Advance Chronic Pain Research, Baltimore, MD, United States.
Pain. 2024 Jul 1;165(7):1531-1549. doi: 10.1097/j.pain.0000000000003158. Epub 2024 Jan 23.
Metabolism is inextricably linked to every aspect of cellular function. In addition to energy production and biosynthesis, metabolism plays a crucial role in regulating signal transduction and gene expression. Altered metabolic states have been shown to maintain aberrant signaling and transcription, contributing to diseases like cancer, cardiovascular disease, and neurodegeneration. Metabolic gene polymorphisms and defects are also associated with chronic pain conditions, as are increased levels of nerve growth factor (NGF). However, the mechanisms by which NGF may modulate sensory neuron metabolism remain unclear. This study demonstrated that intraplantar NGF injection reprograms sensory neuron metabolism. Nerve growth factor suppressed mitochondrial pyruvate oxidation and enhanced lactate extrusion, requiring 24 hours to increase lactate dehydrogenase A and pyruvate dehydrogenase kinase 1 (PDHK1) expression. Inhibiting these metabolic enzymes reversed NGF-mediated effects. Remarkably, directly disrupting mitochondrial pyruvate oxidation induced severe, persistent allodynia, implicating this metabolic dysfunction in chronic pain. Nanopore long-read sequencing of poly(A) mRNA uncovered extensive transcriptomic changes upon metabolic disruption, including altered gene expression, splicing, and poly(A) tail lengths. By linking metabolic disturbance of dorsal root ganglia to transcriptome reprogramming, this study enhances our understanding of the mechanisms underlying persistent nociceptive sensitization. These findings imply that impaired mitochondrial pyruvate oxidation may drive chronic pain, possibly by impacting transcriptomic regulation. Exploring these metabolite-driven mechanisms further might reveal novel therapeutic targets for intractable pain.
代谢与细胞功能的各个方面都密切相关。除了能量产生和生物合成外,代谢在调节信号转导和基因表达方面也起着至关重要的作用。已经表明,改变的代谢状态可以维持异常的信号和转录,导致癌症、心血管疾病和神经退行性疾病等疾病。代谢基因多态性和缺陷也与慢性疼痛状况有关,神经生长因子 (NGF) 水平升高也是如此。然而,NGF 可能调节感觉神经元代谢的机制仍不清楚。本研究表明,足底内注射 NGF 可重新编程感觉神经元代谢。NGF 抑制线粒体丙酮酸氧化并增强乳酸盐外排,需要 24 小时才能增加乳酸脱氢酶 A 和丙酮酸脱氢酶激酶 1 (PDHK1) 的表达。抑制这些代谢酶可逆转 NGF 介导的作用。值得注意的是,直接破坏线粒体丙酮酸氧化会引起严重且持续的痛觉过敏,表明这种代谢功能障碍与慢性疼痛有关。聚(A)mRNA 的纳米孔长读测序揭示了代谢干扰后广泛的转录组变化,包括基因表达、剪接和聚(A)尾长度的改变。通过将背根神经节的代谢紊乱与转录组重编程联系起来,本研究增强了我们对持续伤害感受敏化潜在机制的理解。这些发现表明,线粒体丙酮酸氧化受损可能会导致慢性疼痛,可能通过影响转录组调节。进一步探索这些代谢物驱动的机制可能会为难治性疼痛揭示新的治疗靶点。