A neuron-specific Isca1 knockout rat developments multiple mitochondrial dysfunction syndromes

Background:Multiple mitochondrial dysfunction syndromes(MMDS)are rare mitochondrial diseases caused by mutation of mitochondrial iron–sulfur cluster synthesis proteins.This study established a rat model simulating MMDS5 disease in the nervous system to investigate its pathological features and neuronal death.Methods:We generated neuron-specific Isca1 knockout rat(Isca1 flox/flox-NeuN-Cre)using CRISPR-Cas9 technology.The brain structure changes of CKO rats were studied with MRI,and the behavior abnormalities were analyzed through gait analysis and open field tests,Y maze tests and food maze tests.The pathological changes of neurons were analyzed through H&E staining,Nissl staining,and Golgi staining.Mitochondrial damage was assessed by TEM,western blot and ATP assay,and the morphology of neurons was assessed by WGA immunofluorescence to detect the death of neurons.Results:This study established the disease model of MMDS5 in the nervous system for the first time,and found that after Isca1 loss,the rats suffered from developmental retardation,epilepsy,memory impairment,massive neuronal death,reduced number of Nissl bodies and dendritic spines,mitochondrial fragmentation,cristae fracture,reduced content of respiratory chain complex protein,and reduced production of ATP.Isca1 knockout caused neuronal oncosis.Conclusions:This rat model can be used to study the pathogenesis of MMDS.In addition,compared with human MMDS5,the rat model can survive up to 8 weeks of age,effectively extending the window of clinical treatment research,and can be used for the treatment of neurological symptoms in other mitochondrial diseases.

Intermittent Theta Burst Stimulation Attenuates Cognitive Deficits and Alzheimer’s Disease-Type Pathologies via ISCA1-Mediated Mitochondrial Modulation in APP/PS1 Mice

Intermittent theta burst stimulation(iTBS),a time-saving and cost-effective repetitive transcranial magnetic stimulation regime,has been shown to improve cognition in patients with Alzheimer’s disease(AD).However,the specific mechanism underlying iTBS-induced cognitive enhancement remains unknown.Previous studies suggested that mitochondrial functions are modulated by magnetic stimulation.Here,we showed that iTBS upregulates the expression of iron-sulfur cluster assembly 1(ISCA1,an essential regulatory factor for mitochondrial respiration)in the brain of APP/PS1 mice.In vivo and in vitro studies revealed that iTBS modulates mitochondrial iron-sulfur cluster assembly to facilitate mitochondrial respiration and function,which is required for ISCA1.Moreover,iTBS rescues cognitive decline and attenuates AD-type pathologies in APP/PS1 mice.The present study uncovers a novel mechanism by which iTBS modulates mitochondrial respiration and function via ISCA1-mediated iron-sulfur cluster assembly to alleviate cognitive impairments and pathologies in AD.We provide the mechanistic target of iTBS that warrants its therapeutic potential for AD patients.

隐花色素蛋白和铁硫簇蛋白相互作用及其在褐飞虱发育与生殖中的作用

【目的】在真核生物中验证隐花色素蛋白(Cryptochrome)/铁硫簇蛋白(Iron-sulfur cluster assembly1)的相互作用,研究2种蛋白在褐飞虱Nilaparvata lugens发育和生殖过程中的作用,为二者在磁感受机制中的协同作用及磁场对昆虫生理状态的调控机制提供依据和新的研究方向。【方法】通过酵母双杂交系统对褐飞虱Ⅰ型隐花色素蛋白/Ⅱ隐花色素蛋白与铁硫簇蛋白的相互作用进行验证。在褐飞虱3龄若虫和羽化第1天成虫中建立Ⅰ型隐花色素蛋白和铁硫簇蛋白基因RNAi(RNA interference)沉默模型,并采用RT-qPCR检测2个基因沉默效率,统计沉默虫体的若虫历期和产卵量。【结果】褐飞虱Ⅰ型隐花色素蛋白与铁硫簇蛋白存在相互作用,而Ⅱ隐花色素蛋白与铁硫簇蛋白不存在相互作用。褐飞虱3龄若虫和羽化第1天成虫中成功建立Ⅰ型隐花色素蛋白和铁硫簇蛋白基因RNAi沉默模型,在注射dsRNA后第2天、第4天和第6天时,2个基因的沉默效率均能达到70%以上。Ⅰ型隐花色素蛋白和铁硫簇蛋白基因沉默虫体的若虫历期无明显变化,但是产卵量受到显著性抑制。【结论】褐飞虱Ⅰ型隐花色素蛋白和铁硫簇蛋白存在相互作用,二者在褐飞虱生殖过程中发挥重要作用。