McCully Kilmer S
Pathology and Laboratory Medicine Service, Boston Veterans Affairs Medical Center, and Department of Pathology, Harvard Medical School, Boston, MA, USA
Ann Clin Lab Sci. 2019 Sep;49(4):425-438.
The purpose of this review is to elucidate how low blood cholesterol promotes mitochondrial dysfunction and mortality by the loss of thioretinaco ozonide from opening of the mitochondrial permeability transition pore (mPTP). Mortality from infections and cancer are both inversely associated with blood cholesterol, as determined by multiple cohort studies from 10 to 30 years earlier. Moreover, low-density lipoprotein (LDL) is inversely related to all-cause and/or cardiovascular mortality, as determined by followup study of elderly cohorts. LDL adheres to and inactivates most microorganisms and their toxins, causing aggregation of LDL and homocysteinylated autoantibodies which obstruct vasa vasorum and produce intimal microabscesses, the vulnerable atherosclerotic plaques. The active site of mitochondrial oxidative phosphorylation and adenosine triphosphate (ATP) biosynthesis is proposed to consist of thioretinaco, a complex of two molecules of thioretinamide with cobalamin, oxidized to the disulfonium thioretinaco ozonide and complexed with oxygen, nicotinamide adenine dinucleotide (NAD), phosphate, and ATP. Loss of the active site complex from mitochondria results from the opening of the mPTP and from decomposition of the disulfonium active site by electrophilic carcinogens, oncogenic viruses, microbes, and by reactive oxygen radicals from ionizing and non-ionizing radiation. Suppression of innate immunity is caused by the depletion of adenosyl methionine because of increased polyamine biosynthesis, resulting in inhibition of nitric oxide and peroxynitrite biosynthesis. Opening of the mPTP produces a loss of thioretinaco ozonide from mitochondria. This loss impairs ATP biosynthesis and causes the mitochondrial dysfunction observed in carcinogenesis, atherosclerosis, aging and dementia. Cholesterol inhibits the opening of the mPTP by preventing integration of the pro-apoptotic Bcl-2-associated X protein (BAX) in the outer mitochondrial membrane. This inhibition explains how elevated LDL reduces mitochondrial dysfunction by preventing loss of the active site of oxidative phosphorylation from mitochondria.
本综述的目的是阐明低血胆固醇如何通过线粒体通透性转换孔(mPTP)开放导致硫代视黄醇臭氧化物丧失,从而促进线粒体功能障碍和死亡。10至30年前的多项队列研究表明,感染和癌症导致的死亡率均与血胆固醇呈负相关。此外,老年队列的随访研究表明,低密度脂蛋白(LDL)与全因死亡率和/或心血管死亡率呈负相关。LDL能黏附并使大多数微生物及其毒素失活,导致LDL和同型半胱氨酸化自身抗体聚集,阻塞滋养血管并产生内膜微脓肿,即易损动脉粥样硬化斑块。线粒体氧化磷酸化和三磷酸腺苷(ATP)生物合成的活性位点被认为由硫代视黄醇组成,它是由两个硫代视黄酰胺分子与钴胺素形成的复合物,氧化为二硫鎓硫代视黄醇臭氧化物并与氧气、烟酰胺腺嘌呤二核苷酸(NAD)、磷酸盐和ATP结合。线粒体活性位点复合物的丧失是由于mPTP开放以及二硫鎓活性位点被亲电子致癌物、致癌病毒、微生物以及电离和非电离辐射产生的活性氧自由基分解所致。由于多胺生物合成增加导致腺苷甲硫氨酸耗竭,从而抑制了先天性免疫,导致一氧化氮和过氧亚硝酸盐生物合成受到抑制。mPTP开放导致线粒体中硫代视黄醇臭氧化物丧失。这种丧失损害了ATP生物合成,并导致在致癌作用、动脉粥样硬化、衰老和痴呆中观察到的线粒体功能障碍。胆固醇通过阻止促凋亡的Bcl-2相关X蛋白(BAX)整合到线粒体外膜中来抑制mPTP开放。这种抑制作用解释了升高的LDL如何通过防止线粒体氧化磷酸化活性位点丧失来减少线粒体功能障碍。