Department of Medicinal Chemistry, The University of Kansas, Lawrence, KS 66045, U.S.A.
ASN Neuro. 2010 Aug 11;2(4):e00040. doi: 10.1042/AN20100015.
Increasing the expression of Hsp70 (heat-shock protein 70) can inhibit sensory neuron degeneration after axotomy. Since the onset of DPN (diabetic peripheral neuropathy) is associated with the gradual decline of sensory neuron function, we evaluated whether increasing Hsp70 was sufficient to improve several indices of neuronal function. Hsp90 is the master regulator of the heat-shock response and its inhibition can up-regulate Hsp70. KU-32 (N-{7-[(2R,3R,4S,5R)-3,4-dihydroxy-5-methoxy-6,6-dimethyl-tetrahydro-2H-pyran-2-yloxy]-8-methyl-2-oxo-2H-chromen-3-yl}acetamide) was developed as a novel, novobiocin-based, C-terminal inhibitor of Hsp90 whose ability to increase Hsp70 expression is linked to the presence of an acetamide substitution of the prenylated benzamide moiety of novobiocin. KU-32 protected against glucose-induced death of embryonic DRG (dorsal root ganglia) neurons cultured for 3 days in vitro. Similarly, KU-32 significantly decreased neuregulin 1-induced degeneration of myelinated Schwann cell DRG neuron co-cultures prepared from WT (wild-type) mice. This protection was lost if the co-cultures were prepared from Hsp70.1 and Hsp70.3 KO (knockout) mice. KU-32 is readily bioavailable and was administered once a week for 6 weeks at a dose of 20 mg/kg to WT and Hsp70 KO mice that had been rendered diabetic with streptozotocin for 12 weeks. After 12 weeks of diabetes, both WT and Hsp70 KO mice developed deficits in NCV (nerve conduction velocity) and a sensory hypoalgesia. Although KU-32 did not improve glucose levels, HbA1c (glycated haemoglobin) or insulin levels, it reversed the NCV and sensory deficits in WT but not Hsp70 KO mice. These studies provide the first evidence that targeting molecular chaperones reverses the sensory hypoalgesia associated with DPN.
增加热休克蛋白 70(Hsp70)的表达可以抑制轴突切断后感觉神经元的变性。由于 DPN(糖尿病周围神经病变)的发作与感觉神经元功能的逐渐下降有关,我们评估了增加 Hsp70 是否足以改善神经元功能的几个指标。Hsp90 是热休克反应的主要调节剂,其抑制作用可以上调 Hsp70。KU-32(N-[(2R,3R,4S,5R)-3,4-二羟基-5-甲氧基-6,6-二甲基四氢-2H-吡喃-2-基氧基]-8-甲基-2-氧代-2H-色烯-3-基]乙酰胺)是一种新型的、基于新生霉素的、C 端 Hsp90 抑制剂,其增加 Hsp70 表达的能力与新生霉素的苯甲酰胺部分的取代基为乙酰氨基有关。KU-32 可防止在体外培养 3 天的胚胎 DRG(背根神经节)神经元因葡萄糖诱导而死亡。同样,KU-32 显著减少了神经调节蛋白 1 诱导的 WT(野生型)小鼠骨髓鞘施万细胞 DRG 神经元共培养物的变性。如果共培养物是从 Hsp70.1 和 Hsp70.3 KO(敲除)小鼠中制备的,则这种保护就会丢失。KU-32 易于生物利用,每周给药一次,连续 6 周,剂量为 20mg/kg,用于链脲佐菌素 12 周诱导糖尿病的 WT 和 Hsp70 KO 小鼠。糖尿病 12 周后,WT 和 Hsp70 KO 小鼠的 NCV(神经传导速度)和感觉性痛觉减退均出现缺陷。尽管 KU-32 没有改善血糖、HbA1c(糖化血红蛋白)或胰岛素水平,但它逆转了 WT 小鼠的 NCV 和感觉缺陷,但没有逆转 Hsp70 KO 小鼠的 NCV 和感觉缺陷。这些研究首次提供了靶向分子伴侣可逆转与 DPN 相关的感觉性痛觉减退的证据。