药物抑制肉毒碱棕榈酰转移酶 1 可恢复三功能蛋白缺乏型成纤维细胞中线粒体氧化磷酸化。
Pharmacological inhibition of carnitine palmitoyltransferase 1 restores mitochondrial oxidative phosphorylation in human trifunctional protein deficient fibroblasts.
机构信息
CHU de Tours, Médecine Pédiatrique, Tours, France, and INSERM U1069, Université François Rabelais, Tours, France.
CHU de Tours, Médecine Pédiatrique, Tours, France, and INSERM U1069, Université François Rabelais, Tours, France.
出版信息
Biochim Biophys Acta Mol Basis Dis. 2017 Jun;1863(6):1292-1299. doi: 10.1016/j.bbadis.2017.04.005. Epub 2017 Apr 6.
BACKGROUND
Mitochondrial Trifunctional Protein deficiency (TFPD) is a severe genetic disease characterized by altered energy metabolism and accumulation of long-chain (LC) acylcarnitines in blood and tissues. This accumulation could impair the mitochondrial oxidative phosphorylation (OxPhos), contributing to the non-optimal outcome despite conventional diet therapy with medium-chain triglycerides (MCT).
METHOD
Acylcarnitine and OxPhos parameters were measured in TFPD-fibroblasts obtained from 8 children and cultured in medium mimicking fasting (LCFA) or conventional treatment (MCT), with or without Etomoxir (ETX) an inhibitor of carnitine palmitoyltransferase 1 (CPT1) activity, and were compared to results obtained with fibroblasts from 5 healthy-control children. The effects of various acylcarnitines were also tested on control fibroblasts.
RESULTS
In the LCFA-condition, TFPD-fibroblasts demonstrated a large accumulation of LC-acylcarnitines associated with decreased O-consumption (63±3% of control, P<0.001) and ATP production (67±5%, P<0.001) without modification of coupling efficiency. A dose-dependent decrease in O-consumption was reproduced in control fibroblasts by addition of increasing dose of LC-acylcarnitines, while it was almost preserved with MC-acylcarnitines. The MCT-condition reduced LC-acylcarnitine accumulation and partially improved O-consumption (80±3%, P<0.01) in TFPD-fibroblasts. The addition of ETX in both LCFA- and MCT-conditions normalized acylcarnitine profiles and restored O-consumption and ATP production at the same levels than control.
CONCLUSION
Accumulation of LC-acylcarnitines plays a major role in the pathophysiology of TFPD, reducing OxPhos capacities. These deleterious effects could be partially prevented by MCT-therapy and totally corrected by ETX. Inhibition of CPT1 may be view as a new therapeutic target for patients with a severe form of TFPD.
背景
线粒体三功能蛋白缺乏症（TFPD）是一种严重的遗传性疾病，其特征为能量代谢改变和血液及组织中长链酰基辅酶 A（LCAC）的积累。这种积累可能会损害线粒体氧化磷酸化（OxPhos），导致尽管采用中链甘油三酯（MCT）进行常规饮食治疗，仍无法获得理想的结果。
方法
从 8 名患儿中获取 TFPD 成纤维细胞并进行培养，模仿禁食（LCFA）或常规治疗（MCT）条件，分别用或不用肉碱棕榈酰转移酶 1（CPT1）活性抑制剂 Etomoxir（ETX）处理，测量酰基辅酶 A 和 OxPhos 参数，并与 5 名健康对照儿童的成纤维细胞的结果进行比较。还测试了各种酰基辅酶 A 对对照成纤维细胞的影响。
结果
在 LCFA 条件下，TFPD 成纤维细胞表现出 LCAC 的大量积累，伴随着 O 消耗减少（对照的 63±3%，P<0.001）和 ATP 生成减少（对照的 67±5%，P<0.001），而耦合效率没有改变。在对照成纤维细胞中，随着 LCAC 剂量的增加，O 消耗呈剂量依赖性下降，而 MCAC 则几乎保持不变。在 TFPD 成纤维细胞中，MCT 条件减少了 LCAC 的积累，并部分改善了 O 消耗（80±3%，P<0.01）。在 LCFA 和 MCT 条件下添加 ETX 可使酰基辅酶 A 谱正常化，并将 O 消耗和 ATP 生成恢复到与对照相同的水平。
结论
LCAC 的积累在 TFPD 的病理生理学中起主要作用，降低了 OxPhos 能力。MCT 治疗可部分预防这些有害影响，而 ETX 则可完全纠正。CPT1 的抑制作用可能被视为严重 TFPD 患者的新治疗靶点。
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