Missense mutations in UBQLN2 cause X-linked dominant inheritance of amyotrophic lateral sclerosis with frontotemporal dementia (ALS/FTD). UBQLN2 belongs to a family of four highly homologous proteins expressed in humans that play diverse roles in maintaining proteostasis, but whether one isoform can substitute for another is not known. Here, we tested whether overexpression of UBQLN1 can alleviate disease in the P497S UBQLN2 mouse model of ALS/FTD by crossing transgenic (Tg) mouse lines expressing the two proteins and characterizing the resulting genotypes using a battery of pathologic and behavioral tests. The pathologic findings revealed UBQLN1 overexpression dramatically reduced the burden of UBQLN2 inclusions, neuronal loss and disturbances in proteostasis in double Tg mice compared to single P497S Tg mice. The beneficial effects of UBQLN1 overexpression were primarily confirmed by behavioral improvements seen in rotarod performance and grip strength in male, but not female mice. Paradoxically, although UBQLN1 overexpression reduced pathologic signatures of disease in P497S Tg mice, female mice had larger percentage of body weight loss than males, and this correlated with a corresponding lack of behavioral improvements in the females. These findings lead us to speculate that methods to upregulate UBQLN1 expression may reduce pathogenicity caused by UBQLN2 mutations, but may also lead to gender-specific outcomes that will have to be carefully weighed with the therapeutic benefits of UBQLN1 upregulation.

中文翻译：

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UBQLN1的过表达减少了ALS / FTD的P497S UBQLN2小鼠模型的神经病理

UBQLN2的错义突变导致肌萎缩性侧索硬化与额颞痴呆（ALS / FTD）的X连锁显性遗传。UBQLN2属于人类表达的四种高度同源蛋白家族，在维持蛋白稳态中起着多种作用，但尚不清楚一种同工型是否可以替代另一种。在这里，我们测试了UBQLN1的过表达是否可以通过跨表达两种蛋白质的转基因（Tg）小鼠品系并使用一系列病理学和行为学测试来表征所产生的基因型，从而缓解ALS / FTD的P497S UBQLN2小鼠模型中的疾病。病理结果表明，与单只P497S Tg小鼠相比，双Tg小鼠的UBQLN1过表达显着降低了UBQLN2内含物的负担，神经元丢失和蛋白稳态障碍。UBQLN1过表达的有益作用主要由雄性小鼠的轮转性能和抓地力方面的行为改善所证实，而雌性小鼠却没有。矛盾的是，尽管UBQLN1过表达减少了P497S Tg小鼠的疾病病理特征，但雌性小鼠的体重减轻百分比高于雄性，这与雌性缺乏相应的行为改善有关。这些发现使我们推测，上调UBQLN1表达的方法可能会减少UBQLN2突变​​引起的致病性，但也可能导致针对性别的特定结局，必须仔细权衡UBQLN1上调的治疗益处。矛盾的是，尽管UBQLN1过表达减少了P497S Tg小鼠的疾病病理特征，但雌性小鼠的体重减轻百分比高于雄性，这与雌性缺乏相应的行为改善有关。这些发现使我们推测，上调UBQLN1表达的方法可能会减少UBQLN2突变​​引起的致病性，但也可能导致针对性别的特定结局，必须仔细权衡UBQLN1上调的治疗益处。矛盾的是，尽管UBQLN1过表达减少了P497S Tg小鼠的疾病病理特征，但雌性小鼠的体重减轻百分比高于雄性，这与雌性缺乏相应的行为改善有关。这些发现使我们推测，上调UBQLN1表达的方法可能会减少UBQLN2突变​​引起的致病性，但也可能导致针对性别的特定结局，必须仔细权衡UBQLN1上调的治疗益处。