CLN1 disease (OMIM #256730) is an inherited neurological disorder of early childhood with epileptic seizures and premature death. It is associated with mutations in CLN1 coding for Palmitoyl-Protein Thioesterase 1 (PPT1), a lysosomal enzyme which affects the recycling and degradation of lipid-modified (S-acylated) proteins by removing palmitate residues. Transcriptomic evidence from a neuronal-like cellular model derived from differentiated SH-SY5Y cells disclosed the potential negative roles of CLN1 overexpression, affecting the elongation of neuronal processes and the expression of selected proteins of the synaptic region. Bioinformatic inquiries of transcriptomic data pinpointed a dysregulated expression of several genes coding for proteins related to voltage-gated ion channels, including subunits of calcium and potassium channels (VGCC and VGKC). In SH-SY5Y cells overexpressing CLN1 (SH-CLN1 cells), the resting potential and the membrane conductance in the range of voltages close to the resting potential were not affected. However, patch-clamp recordings indicated a reduction of Ba²⁺ currents through VGCC of SH-CLN1 cells; Ca²⁺ imaging revealed reduced Ca²⁺ influx in the same cellular setting. The results of the biochemical and morphological investigations of CACNA2D2/α₂δ-2, an accessory subunit of VGCC, were in accordance with the downregulation of the corresponding gene and consistent with the hypothesis that a lower number of functional channels may reach the plasma membrane. The combined use of 4-AP and NS-1643, two drugs with opposing effects on K_v11 and K_v12 subfamilies of VGKC coded by the KCNH gene family, provides evidence for reduced functional K_v12 channels in SH-CLN1 cells, consistent with transcriptomic data indicating the downregulation of KCNH4. The lack of compelling evidence supporting the palmitoylation of many ion channels subunits investigated in this study stimulates inquiries about the role of PPT1 in the trafficking of channels to the plasma membrane. Altogether, these results indicate a reduction of functional voltage-gated ion channels in response to CLN1/PPT1 overexpression in differentiated SH-SY5Y cells and provide new insights into the altered neuronal excitability which may underlie the severe epileptic phenotype of CLN1 disease. It remains to be shown if remodeling of such functional channels on plasma membrane can occur as a downstream effect of CLN1 disease.

CLN1疾病（OMIM＃256730）是儿童早期的遗传性神经系统疾病，伴有癫痫发作和过早死亡。它与突变有关CLN1编码棕榈酰蛋白质硫酯酶1（PPT1）的溶酶体酶，可通过去除棕榈酸酯残基来影响脂质修饰（S-酰化）蛋白的回收和降解。来自分化的SH-SY5Y细胞的神经元样细胞模型的转录组证据显示，其潜在的负面作用CLN1过度表达，影响神经元过程的延伸和突触区域所选蛋白的表达。转录组数据的生物信息学查询指出了编码与电压门控离子通道（包括钙和钾通道的亚基）（VGCC和VGKC）相关的蛋白质的几个基因的表达失调。在SH-SY5Y细胞中过表达CLN1 （SH-CLN1静息电位和接近静息电位的电压范围内的膜电导不受影响。然而，膜片钳记录表明通过SH-的VGCC减少了Ba ²⁺电流CLN1细胞; Ca ²⁺成像显示在相同的细胞环境中Ca ^2+内流减少。CACNA2D2的生物化学和形态的调查/α的结果₂ δ-2，VGCC的附件子单元，分别按照与相应的基因的下调和与假设一致，即功能性的信道的较低数目可以达到质膜。联合使用4-AP和NS-1643，这两种药物对VGKC的K _v 11和K _v 12亚家族有相反的作用，国民党基因家族，为减少SH-中功能性K _v 12通道提供证据CLN1 细胞，与表明其下调的转录组数据一致 氯化钾4。缺乏令人信服的证据支持本研究中研究的许多离子通道亚基的棕榈酰化，激发了人们对PPT1在通道向质膜运输中的作用的疑问。总而言之，这些结果表明，响应于CLN1/ PPT1在分化的SH-SY5Y细胞中过度表达，并为神经元兴奋性改变提供了新的见解，而神经兴奋性改变可能是CLN1疾病的严重癫痫表型的基础。质膜上这种功能性通道的重塑是否会作为CLN1疾病的下游效应而发生，还有待证明。