Protein synthesis modulation as a therapeutic approach for amyotrophic lateral sclerosis and frontotemporal dementia

Protein synthesis is essential for cells to perform life metabolic processes.Pathological alterations of protein content can lead to particular diseases.Cells have an intrinsic array of mechanisms and pathways that are activated when protein misfolding,accumulation,aggregation or mislocalization occur.Some of them(like the unfolded protein response)represent complex interactions between endoplasmic reticulum sensors and elongation factors that tend to increase expression of chaperone proteins and/or repress translation in order to restore protein homeostasis(also known as proteostasis).This is even more important in neurons,as they are very susceptible to harmful effects associated with protein overload and proteostatic mechanisms are less effective with age.Several neurodegenerative pathologies such as Alzheimer’s,Parkinson’s,and Huntington’s diseases,amyotrophic lateral sclerosis and frontotemporal dementia exhibit a particular molecular signature of distinct,unbalanced protein overload.In amyotrophic lateral sclerosis and frontotemporal dementia,the majority of cases present intracellular inclusions of ubiquitinated transactive response DNA-binding protein of 43 kDa(TDP-43).TDP-43 is an RNA binding protein that participates in RNA metabolism,among other functions.Dysregulation of TDP-43(e.g.aggregation and mislocalization)can dramatically affect neurons,and this has been linked to disease development.Expression of amyotrophic lateral sclerosis/frontotemporal dementia TDP-43-related mutations in cellular and animal models has been shown to recapitulate key features of the amyotrophic lateral sclerosis/frontotemporal dementia disease spectrum.These variants can be causative of degeneration onset and progression.Most neurodegenerative diseases(including amyotrophic lateral sclerosis and frontotemporal dementia)have no cure at the moment;however,modulating translation has recently emerged as an attractive approach that can be performed at several steps(i.e.regulating activation of initiation and elongation factors,inhibiting unfolded protein response activation or inducing chaperone expression and activity).This review focuses on the features of protein imbalance in neurodegenerative disorders and the relevance of developing therapeutical compounds aiming at restoring proteostasis.We strive to highlight the importance of research on drugs that,not only restore protein imbalance without compromising translational activity of cells,but are also as safe as possible for the patients.

家族性肌萎缩侧索硬化症10型的临床特征和基因突变分析

【目的】探讨家族性肌萎缩侧索硬化症10型患者的临床特点、分子遗传学特征。【方法】对2013年中山大学附属第一医院神经科门诊就诊发现的该病家系行高通量测序法检测其TARDBP基因外显子突变类型。【结果】该家系中3代共5例患者,每代均有患者且男女都有发病,符合常染色体显性遗传特征。该家系患者于50岁左右起病,病情进展迅速,从出现临床症状到最终死亡仅为8~18个月左右。TARDBP基因检测结果显示,先证者的exon6发生了c.892 G>A的杂合突变,另在第3代家系其他成员中,检测发现了3人携带与先证者相同的突变类型,但目前尚未发病。【结论】家族性肌萎缩侧索硬化症10型是一类病情进展迅速、生存时期短暂的运动神经元疾病。目前无有效治疗方法,对患者进行遗传咨询并对其下一代的出生进行产前诊断,遗传咨询和中断遗传链是防治该病的关键措施。