Ahmed Mohammad Ejaz, Suhail Hamid, Nematullah Mohammad, Hoda Md Nasrul, Giri Shailendra, Ahmad Abdullah Shafique
Department of Neurology, Henry Ford Health, Detroit, MI 48202.
bioRxiv. 2024 Jun 28:2024.06.25.600422. doi: 10.1101/2024.06.25.600422.
Traumatic brain injury (TBI) is a significant public health concern characterized by a complex cascade of cellular events. TBI induces adenosine monophosphate-activated protein kinase (AMPK) dysfunction impairs energy balance activates inflammatory cytokines and leads to neuronal damage. AMPK is a key regulator of cellular energy homeostasis during inflammatory responses. Recent research has revealed its key role in modulating the inflammatory process in TBI. Following TBI the activation of AMPK can influence various important pathways and mechanisms including metabolic pathways and inflammatory signaling. Our study investigated the effects of post-TBI loss of AMPK function on functional outcomes inflammasome activation, and inflammatory cytokine production. Male C57BL/6 adult wild-type (WT) and AMPK knockout (AMPK-KO) mice were subjected to a controlled cortical impact (CCI) model of TBI or sham surgery. The mice were tested for behavioral impairment at 24 h post-TBI thereafter, mice were anesthetized, and their brains were quickly removed for histological and biochemical evaluation. we investigated inflammasome activation in mixed glial cells stimulated with lipopolysaccharides+ Interferon-gamma (LI) (0.1 μg/20 ng/ml LPS/IFNg) for 6 h to induce an inflammatory response. Estimating the nucleotide-binding domain, leucine-rich-containing family pyrin domain containing western blotting ELISA and qRT-PCR performed 3 (NLRP3) inflammasome activation and cytokine production. Our findings suggest that TBI leads to reduced AMPK phosphorylation in WT mice and that the loss of AMPK correlates with worsened behavioral deficits at 24 h post-TBI in AMPK-KO mice as compared to WT mice. Moreover compared with the WT mice AMPK-KO mice exhibit exacerbated NLRP3 inflammasome activation and increased expression of proinflammatory mediators such as IL-1b IL-6 TNF-a iNOS and Cox 2. These results align with the studies using brain glial cells under inflammatory conditions, demonstrating greater activation of inflammasome components in AMPK-KO mice than in WT mice. Our results highlighted the critical role of AMPK in TBI outcomes. We found that the absence of AMPK worsens behavioral deficits and heightens inflammasome-mediated inflammation thereby exacerbating brain injury after TBI. Restoring AMPK activity after TBI could be a promising therapeutic approach for alleviating TBI-related damage.
创伤性脑损伤（TBI）是一个重大的公共卫生问题，其特征是一系列复杂的细胞事件。TBI会导致单磷酸腺苷激活的蛋白激酶（AMPK）功能障碍，损害能量平衡，激活炎性细胞因子，并导致神经元损伤。AMPK是炎症反应期间细胞能量稳态的关键调节因子。最近的研究揭示了其在调节TBI炎症过程中的关键作用。TBI后，AMPK的激活可影响各种重要途径和机制，包括代谢途径和炎症信号传导。我们的研究调查了TBI后AMPK功能丧失对功能结局、炎性小体激活和炎性细胞因子产生的影响。雄性C57BL/6成年野生型（WT）和AMPK基因敲除（AMPK-KO）小鼠接受TBI的控制性皮质撞击（CCI）模型或假手术。在TBI后24小时对小鼠进行行为损伤测试，此后，将小鼠麻醉，并迅速取出其大脑进行组织学和生化评估。我们研究了用脂多糖+干扰素-γ（LI）（0.1μg/20ng/ml LPS/IFNg）刺激混合神经胶质细胞6小时以诱导炎症反应时炎性小体的激活情况。通过蛋白质印迹法、酶联免疫吸附测定法和定量逆转录聚合酶链反应评估含核苷酸结合结构域、富含亮氨酸的家族pyrin结构域3（NLRP3）炎性小体的激活和细胞因子的产生。我们的研究结果表明，TBI导致WT小鼠中AMPK磷酸化降低，并且与WT小鼠相比，AMPK-KO小鼠在TBI后24小时AMPK的缺失与行为缺陷恶化相关。此外，与WT小鼠相比，AMPK-KO小鼠表现出NLRP3炎性小体激活加剧以及促炎介质如白细胞介素-1β、白细胞介素-6、肿瘤坏死因子-α、诱导型一氧化氮合酶和环氧化酶-2的表达增加。这些结果与在炎症条件下使用脑胶质细胞的研究一致，表明AMPK-KO小鼠中炎性小体成分的激活比WT小鼠中更强烈。我们的结果突出了AMPK在TBI结局中的关键作用。我们发现，AMPK的缺失会使行为缺陷恶化，并加剧炎性小体介导的炎症，从而加重TBI后的脑损伤。TBI后恢复AMPK活性可能是减轻TBI相关损伤的一种有前景的治疗方法。
