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Firstly, all the DHA that gets into the brain is heavily regulated by the MFSD2A protein:

Using cell-based assays and brain uptake studies in Mfsd2a−/− mice, they next show that Mfsd2a transports DHA and fatty acids into the brain across the BBB only in the form of esters with lysophosphatidylcholines (LPCs), but not as free unesterified fatty acids.

They also show that MSFD2A transport protein prefers long-chain fatty acids such as LPC-oleate and LPC-palmitate but does not transport LPCs with less than a 14-carbon acyl chain.

通过对Mfsd2a−/−小鼠的细胞分析和脑摄取研究，他们接下来表明，Mfsd2a仅以溶血磷脂酰胆碱酯(LPCs)的形式将DHA和脂肪酸转运到脑内，而不是以游离未酯化脂肪酸的形式。

他们还表明，MSFD2A转运蛋白更喜欢长链脂肪酸，如lpc-油酸酯和lpc-棕榈酸酯，但不转运少于14碳酰基链的lpc。

So DHA must be bound to lysophosphatidylcholine (LysoPC) to be taken up by the MFSD2A protein.

因此DHA必须与溶血磷脂酰胆碱(LysoPC)结合才能被MFSD2A蛋白摄取。

As an aside, it seems like Red Blood Cells also require DHA to be LysoPC for uptake, based on study 'Blood compartmental metabolism of docosahexaenoic acid (DHA) in humans after ingestion of a single dose of [13C]DHA in phosphatidylcholine'(Lemaitre-Delaunay et. al., 1999) – http://www.jlr.org/content/40/10/1867.full

说句题外话,似乎红细胞也为吸收需要LysoPC DHA,基于研究的血液区划的新陈代谢二十二碳六烯酸(DHA)在人类摄入一剂[13 c] DHA在磷脂酰胆碱。

普通饮食中的DHA是不行的。引用这项研究“海洋-3磷脂:新陈代谢和生物活动”

According to this review, the most predominant PLs in marine sources such as salmon, tuna, rainbow trout and mackerel, is PC, whereas PE is shown to be the second most abundant. Phosphatidylinositol (PI), phosphatidylserine (PS), lysophosphatidylcholine (lyso-PC), and sphingomyelin are found in smaller amounts.

根据这篇综述，在海洋资源中，最主要的PLs是PC，如鲑鱼，金枪鱼，虹鳟和鲭鱼，而PE显示是第二丰富的。磷脂酰肌醇(PI)、磷脂酰丝氨酸(PS)、溶血磷脂酰胆碱(lyso-PC)和鞘磷脂含量较低。

Fish roe is probably an exception though, with “38%–75% of their lipids in the form of phospholipids, with phosphatidylcholine being the predominant lipid class”

鱼卵可能是个例外，“它们38%-75%的脂质是磷脂，磷脂酰胆碱是主要的脂类。”

So most of dietary DHA isn't bound to LysoPC, so that's a process that has to happen after ingestion of DHA.

所以大多数饮食中的DHA并没有与溶血蛋白结合，所以这是一个在摄入DHA后必须发生的过程。

For one, LysoPC is made in the liver, and I wouldn't be surprised if the amount of DHA that ends up in our transport system to begin with is regulated by the liver somehow (I have no proof of this though). Anecdotally, a lot of people with poor liver function don't seem to do well with a lot of DHA in their diet.

首先，溶血蛋白是在肝脏中产生的，如果我们运输系统中DHA的数量以某种方式受到肝脏的控制，我不会感到惊讶(尽管我没有证据)。有趣的是，很多肝功能不佳的人在饮食中摄入大量DHA时似乎效果不佳。

sn-2 DHA seems to absorbed well in the Intestine. 'Intestinal absorption and lymphatic transport of eicosapentaenoic (EPA), docosahexaenoic (DHA), and decanoic acids: dependence on intramolecular triacylglycerol structure.'(Christensen et. al., 1995) – http://ajcn.nutrition.org/content/61/1/56.short

sn-2 DHA在肠内吸收良好。“二十碳五烯(EPA)、二十二碳六烯(DHA)和癸酸的肠道吸收和淋巴运输:依赖于分子内三酰基甘油结构。”

它也可能更好地传输到大脑，“含有dha的结构化磷脂(AceDoPC)的生物学特性，以靶向大脑”

Although the lyso species was purified by HPLC immediately prior to acetylation, around 20% of 1-docosahexaenoyl,2-acetyl-PC was obtained, presumably due to DHA migration to the sn-1 position during the chemical process.

虽然溶酶体在乙酰化前立即被高效液相色谱纯化，但仍获得了约20%的1-二十二碳六烯基，2-乙酰- pc，可能是由于DHA在化学过程中迁移到sn-1位置。

So migration from the sn-2 position to the sn-1 or sn-3 position may offset some of the oxidative resilience seen at sn-2. 'Docosahexaenoic Acid is More Stable to Oxidation when Located at the sn-2 Position of Triacylglycerol Compared to sn-1(3)' (Wijesundera et. al., 2008) – http://link.springer.com/article/10.1007/s11746-008-1224-z

因此，从sn-2位点向sn-1或sn-3位点的迁移可能会抵消一些sn-2位点的氧化弹性。与sn-1相比，二十二碳六烯酸位于三酰基甘油的sn-2位置时更稳定的氧化(3)

As for dietary sources, Farmed Atlantic Salmon still has 80% of it's DHA in the sn-2 position according to 'Positional Distribution of Fatty Acids in Triacylglycerols and Phospholipids from Fillets of Atlantic Salmon (Salmo Salar) Fed Vegetable and Fish Oil Blends' (Ruiz-Lopez et. al., 2015) – http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4515615/

至于饮食来源，养殖大西洋鲑鱼仍然有80%的DHA在sn-2位置，根据“从用蔬菜和鱼油喂养的大西洋鲑鱼(Salmo Salar)鱼片中三酰基甘油和磷脂中脂肪酸的位置分布”

Still, we've got a complex chain of regulation and control over DHA. It's definitely not a question about eating more of it to “get better brain function”.

尽管如此，我们对DHA还是有一个复杂的管理和控制链。这绝对不是一个吃更多咖啡来“改善大脑功能”的问题。

And of course, malfunctions anywhere along the chain, be it a stressed out liver, or malfunctioning MFSD2A, will lead to dys-regulation of the amount of DHA that can get to important tisuses like the brain.

当然，链条上任何地方的故障，无论是肝脏的压力过大，还是MFSD2A的故障，都会导致DHA数量的失调，而DHA可以到达大脑等重要组织。

There is very little difference in plasma DHA levels regardless of the method of delivery based on 'Comparison of the effects of fish and fish-oil capsules on the n 3 fatty acid content of blood cells and plasma phospholipids.' (Harris WS et. al., 2007) – http://www.ncbi.nlm.nih.gov/pubmed/18065578

根据“比较鱼和鱼油胶囊对血细胞中n - 3脂肪酸含量和血浆磷脂的影响”的研究结果，无论使用哪种方式，血浆中DHA含量的差异都很小。

If brain DHA delivery is rate-limited in any case, then for practical measures, would it be “easier” for people to just take a good DHA supplement, while eating other foodstuffs?

如果脑内DHA的供给在任何情况下都是有限的，那么对于实际的措施来说，对人们来说，只吃一份好的DHA补充剂，而吃其他食物是否会“更容易”?

Of course, seafood generally contains a lot more nutrients than just DHA, so it's probably “better” in that sense. However, strictly in terms of DHA delivery, it's hard to make a direct case for seafood. Seafood also suffers simlar DHA oxidised.

当然，海鲜通常含有比DHA多得多的营养成分，所以从这个意义上说，它可能“更好”。然而，严格地说，就DHA的输送而言，很难对海鲜做出直接的解释。海鲜也遭受类似的DHA氧化。

Closing Rant: Preganancy and Early Developmental Needs do not Necessary Reflect other Contexts

It is clear that for Preganant and Breastfeeding mothers, as well as Infants, that no amount of endogneous DHA production is going to supply the needed amounts of DHA for development.

很明显，对于孕妇和哺乳期母亲以及婴儿来说，再多的内生DHA生产也不能满足发育所需的DHA。

However, once those developmental needs are met, can we really say that it is DHA deficiency that is the problem?

然而，一旦这些发育需要得到满足，我们真的能说DHA缺乏是问题所在吗?

This is going to be highly context dependent. For example, if a person was raised DHA deficient to begin with and is now 15 years old with neurological disorders, then yes, adding some DHA transiently is probably going to do well to create the DHA stores needed, which then need to be endogenously regulated and deposited in the right amounts in the right tissues.

这将是高度依赖上下文的。举个例子,如果一个人从小就开始DHA缺乏与神经障碍,现在15岁,那么是的,添加一些DHA是暂时性的DHA可能做好创建存储需要,然后需要从内部监管,把正确的数量在正确的组织。

Even in this case, it is not a simple matter of “eat more DHA and get fixed”. I will guarantee that keeping said sick teenager in a high nn-EMF with adequate DHA will get DHA into their tissues, but still leave them with the same (if not more) problems due to the failure of all other systems.

即使在这种情况下，也不是简单的“多吃DHA并得到修复”。我将保证，保持说生病的青少年在一个高nn-EMF与充足的DHA将DHA进入他们的组织，但仍然留给他们相同的(如果不是更多的)问题，由于所有其他系统的失败。

Or put differently, DHA is not a “stress-reliever” in any sense. It is a critical compound needed to get other critical compounds to the right places for critical function, and requires other critical systems to be working efficiently to perform its task.

或者换句话说，DHA在任何意义上都不是一种“减压剂”。它是一个关键化合物，需要其他关键化合物到正确的位置，以实现关键功能，并需要其他关键系统有效工作，以完成它的任务。

Now take the best case scenario, whereby you have a healthy person under low stress. Will this person benefit from DHA? Maybe 200mg of DHA a week is no problem. But beyond that? Brain requirements don't seem to be that high, and responses to stress seem to be made fragile by extra DHA (see later sections on immune and mitochondrial effects of DHA).

现在假设最好的情况，你有一个健康的人压力很低。这个人会从DHA中受益吗?也许一周200毫克的DHA没有问题。但除此之外呢?大脑的需求似乎没有那么高，额外的DHA似乎会使压力反应变得脆弱(见后面关于DHA的免疫和线粒体作用的部分)。

In any case, we cannot use “DHA is needed during development” to mean “DHA is always needed”. DHA is still critical for young humans, but the beneficial effects on older humans are dubious.

无论如何，我们不能用“DHA是在开发过程中需要的”来表示“DHA总是需要的”。DHA对年轻人仍然至关重要，但对老年人的有益影响值得怀疑。

I'm not going to discuss the rest of the PUFAs other than DHA and EPA. The reader can do an easy search for the harmful effects of excess PUFA – there is almost no way to spin a story supporting consumption of PUFAs beyond whatever minute quantities found in low-PUFA foods.

除了DHA和EPA，我不打算讨论其他的不饱和脂肪酸。读者可以很容易地搜索过量的多不饱和脂肪酸的有害影响——几乎没有办法编造一个故事来支持摄入多不饱和脂肪酸，超过低不饱和脂肪酸食品中的微量。

In fact, you probably don't need any dietary PUFA at all except DHA. Apparent adipocytes can make all the fatty acids that the body needs via DNL. 'De novo lipogenesis in the differentiating human adipocyte can provide all fatty acids necessary for maturation' (Collins et. al., 2011) –http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3151688/

事实上，除了DHA，你可能根本不需要任何多不饱和脂肪酸。显然，脂肪细胞可以通过DNL制造身体所需的所有脂肪酸。“分化中的人类脂肪细胞的从头脂肪生成可以提供成熟所必需的所有脂肪酸”

In separate experiments, the following substrates were used: 1 mM [1-13C]acetate, D-[U-13C]glucose, 0.5 mM [U-13C]pyruvate, and 2 mM [U-13C]glutamine.

在单独的实验中，使用以下底物:1 mM [1- 13c]醋酸酯、D-[U-13C]葡萄糖、0.5 mM [U-13C]丙酮酸酯和2 mM [U-13C]谷氨酰胺。

DHA was not shown in the graph, but since it can be then used to make DHA, it is possible for full endogenous synthesis of DHA from the DNAL process. The efficiency is not known, though it must be somewhat significant to explain the relatively good levels of DHA in populations which do not consume any DHA.

DHA没有显示在图中，但由于它可以用来制造DHA，因此可以从DNAL过程中完全内源性合成DHA。这种功效目前还不清楚，但这一定对解释不摄入任何DHA的人群中DHA含量相对较高有一定意义。

顺便说一句，这可以很好地解释为什么极低脂肪饮食不会导致健康问题，正如丹尼斯·明格尔(Denise Minger)的这篇文章所讨论的。

EPA and DHA don't form ordinary prostaglandins, though the isoprostanes and neuroprostanes they produce during lipid peroxidation behave in many ways like the more common prostaglandins, and their enzymically formed eicosanoids have some functions similar to those of the common prostaglandins. The brain contains a very high concentration of these unstable fatty acids, and they are released in synapses by ordinary excitatory process.

EPA和DHA不能形成普通的前列腺素，尽管它们在脂质过氧化过程中产生的异前列腺素和神经前列腺素在许多方面的行为与更常见的前列腺素类似，而且它们通过酶的方式形成的二十烷类化合物具有与普通前列腺素类似的功能。大脑中含有非常高浓度的不稳定脂肪酸，它们通过普通的兴奋过程在突触中释放。

Well, here's one paper, 'Isoprostanes and Neuroprostanes as Biomarkers of Oxidative Stress in Neurodegenerative Diseases'(Miiler et. al., 2014) – http://www.hindawi.com/journals/omcl/2014/572491/

这里有一篇论文，“异前列腺素和神经前列腺素作为神经退行性疾病中氧化应激的生物标志物”

The literature data indicate that in vivo or postmortem cerebrospinal fluid and brain tissue levels of F2-isoprostanes (F2-IsoPs) especially F4-neuroprotanes (F4-NPs) are significantly increased in some neurodegenerative diseases: multiple sclerosis, Alzheimer's disease, Huntington's disease, and Creutzfeldt-Jakob disease.

文献资料表明，在体内或死后脑脊液和脑组织中，f2 -异前列腺素(F2-IsoPs)特别是f4 -神经蛋白(F4-NPs)水平在某些神经退行性疾病中显著升高，如多发性硬化、阿尔茨海默病、亨廷顿病、克雅氏病等。

This review focuses on the relationship between F2-IsoPs and F4-NPs as biomarkers of oxidative stress and neurodegenerative diseases. We summarize the knowledge of these novel biomarkers of oxidative stress and the advantages of monitoring their formation to better define the involvement of oxidative stress in neurological diseases.

本文就F2-IsoPs和F4-NPs作为氧化应激和神经退行性疾病的生物标志物之间的关系作一综述。我们总结了这些新的氧化应激生物标志物的知识，以及监测其形成的优势，以更好地界定氧化应激在神经系统疾病中的参与。

PUFAs are the most susceptible to free radical attack and, in general, oxidizability increases as the number of double bonds increases.

PUFAs最容易受到自由基的攻击，一般来说，氧化性随着双键数量的增加而增加。

So, the oxidizability of PUFAs can be estimated by the linear increase in the rate of oxidation with the increasing number of active methylene groups located between two bonds. From such correlation, the oxidizability of each PUFA is increased for about twofold for each active methylene group.

因此，PUFAs的可氧化性可以通过氧化速率随键间活性亚甲基数目的增加而线性增加来估计。从这种关联可以看出，每一个活性亚甲基使每一个PUFA的氧化性提高了约两倍。

Thus, the oxidizability of common fatty acids is as follows: linoleic acid (18:2) < arachidonic acid (20:4, n-6) < eicosapentaenoic acid (EPA, 20:5, n-3) < docosahexaenoic acid (DHA, 22:6, n-3)

因此，常见脂肪酸的氧化性如下:亚油酸(18:2)<花生四烯酸(20:4,n-6) <二十碳五烯酸(EPA, 20:5, n-3) <二十二碳六烯酸(DHA, 22:6, n-3)

By the peroxidation of the omega-3 PUFA, EPA and DHA, F-ring IsoPs have been generated. The IsoPs-like compounds generated from this acid are named NeuroPs.

通过n-3多不饱和脂肪酸、EPA和DHA的过氧化作用，生成f环IsoPs。由这种酸生成的类似isops的化合物被命名为NeuroPs。

F3-IsoPs are formed in abundance in vitro and in vivo from EPA nonenzymatically peroxidation, while DHA may be oxidized nonenzymatically into F4-, D4-, E4-, A4-, and J4-neuroprostanes (F4-, D4-, E4-, A4-, and J4-NeuroPs)

EPA在体外和体内通过非酶性过氧化大量形成F3-IsoPs，而DHA可被非酶氧化成F4-、D4-、E4-、A4-和j4 -神经前列腺素(F4-、D4-、E4-、A4-和j4 -神经前列腺素)。

Unlike AA, DHA is highly concentrated in neuronal membranes to the exclusion of other cell types. Moreover, F4-NeuroPs are by far the most abundant products of this pathway in the brain. The quantification of F4-NeuroPs provides a highly selective quantitative window for neuronal oxidative damage in vivo.

与AA不同的是，DHA在神经元膜中高度集中，排除了其他类型的细胞。此外，到目前为止，F4-NeuroPs是该通路在大脑中最丰富的产物。F4-NeuroPs的量化为体内神经元氧化损伤提供了一个高度选择性的定量窗口。

The rest of the paper just goes on to talk about how the Isoprostanes are likely suitable in vivo markers of Neurological conditions.

论文的其余部分将继续讨论异前列腺素是如何适用于神经系统疾病的体内标记物的。

I bring up that paper just to highlight that oxidised DHA is not good. This doesn't say anything about:

•(a) if eating more DHA will lead to excess stores in tissues which are prone to oxidative damage.

多吃DHA是否会导致组织中储存过多的DHA，而这些组织容易受到氧化损伤。

It's more the case that if oxidative damage happens to occur where there is DHA present, then that DHA breaks down into substances we can measure.

更确切地说，如果氧化损伤发生在DHA存在的地方，那么DHA就会分解成我们可以测量的物质。

Another way of arguing for the use of fish oil or other omega-3 fats is to show a correlation between disease and a decreased amount of EPA, DHA, or arachidonic acid in the tissues, and to say “these oils are deficient, the disease is caused by a deficiency of essential fatty acids.”

另一种主张使用鱼油或其他ω- 3脂肪是指相关性疾病和减少数量的EPA, DHA,或组织中花生四烯酸,说“这些油不足,疾病是由于缺乏必需脂肪酸。”

Their “deficiency” in the tissues frequently corresponds to the intensity of oxidative stress and lipid peroxidation; it is usually their presence, rather than their deficiency, that created the disposition for the disease.

它们在组织中的“缺陷”往往与氧化应激和脂质过氧化的强度相对应;通常是它们的存在，而不是缺乏，造成了这种疾病的倾向。

So basically he's saying that the more DHA you have, the more prone that DHA is to oxidative damage, and to oxidative damage of the organism as a whole.

他的意思是DHA越多，DHA就越容易产生氧化损伤，对整个机体也越容易产生氧化损伤。

This is plausible, since DHA would be stored in adipose tissue like any other fatty acid, and would be mobilised like any other fatty acid (though some say that PUFAs are mobilised more readily than more saturated fatty acids).

这是有道理的，因为DHA会像其他脂肪酸一样储存在脂肪组织中，也会像其他脂肪酸一样被调动(尽管有人说不饱和脂肪酸比更多的饱和脂肪酸更容易调动)。

Free DHA in the serum would then be free to be oxidised in the serum (not good), transported to various places in the body (not good), used in mitochondrial ECT, with all the insulin sensitising effect and loss of ROS generation feedback loops (amoungst other bad effects).

血清中的游离DHA会在血清中被氧化(不好)，被运输到身体的各个地方(不好)，用于线粒体ECT，具有胰岛素增敏效应和ROS生成反馈回路的缺失(以及其他不好的影响)。

二十二碳六烯酸在体内形成类异前列腺素化合物(神经前列腺素)

This study focused on the same F4 neuroprostanes (NP) and F2 Isoprostances (IsoPs) mentioned above.

本研究主要针对上述F4神经前列腺素(NP)和F2等前列腺素(IsoPs)。

•In vitro oxidation of equal molar amounts of DHA and Arachidonic Acid (AA) together using iron/ADP/ascorbate. 3.4 times more F4-NPs than F2-IsoPs were formed.

利用铁/ADP/抗坏血酸，在体外氧化等量DHA和花生四烯酸(AA)。形成的F4-NPs是F2-IsoPs的3.4倍。

F4-NPs dominate in pigs, and F2-IsoPs dominate in Rats. Mechanism for differences unknown, and sameple size was tiny.

猪以F4-NPs为主，大鼠以F2-IsoPs为主。差异机制未知，相同大小很小。

•Examine F4-NP levels in cerebrospinal fluid obtained from four patients with Alzheimer’s disease and three age-matched control subjects.

检查从4名阿尔茨海默病患者和3名年龄匹配的对照组获得的脑脊液中F4-NP水平。

F4-NPs were detected in 1–2 ml of cerebrospinal fluid from the control subjects at a level of 64 ± 8 pg/ml.

Concentrations measured in the patients with Alzheimer’s disease were significantly higher (110 ± 12 pg/ml) (p < 0.05)

在阿尔茨海默病患者中检测到的浓度明显更高(110±12 pg/ml) (p < 0.05)。

Again, it is likely that DHA is “spontaenously” and non-enzymatically broken down to these compounds.

Autooxidation of DHA occurs so readily that oxidation products are commonly found in DHA even after minimal handling

(based on 'Lipid peroxidation products are elevated in fish oil diets even in the presence of added antioxidants'. (Gonzalez MJ et. al, 1992))

DHA的自动氧化作用非常容易发生，即使在少量的处理后，氧化产物也普遍存在于DHA中

(基于“即使在添加抗氧化剂的情况下，鱼油饮食中的脂质过氧化产物也会升高”。(冈萨雷斯·乔丹等，1992))

One of the authors of that paper, Jason Morrow, followed up with proposed mechanisms of Neuroprostanes 10 years later in 'Electrophilic Cyclopentenone Neuroprostanes Are Anti-inflammatory Mediators Formed from the Peroxidation of the ω-3 Polyunsaturated Fatty Acid Docosahexaenoic Acid' (Musiek et. al., 2008) – http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2459280/

那篇论文的作者之一Jason Morrow在10年后的“亲电环戊酮神经前列腺素是ω-3多不饱和脂肪酸二十二碳六烯酸的过氧化形成的抗炎介质”中提出了神经前列腺素的机制。

This paper focused on A4-NPs and J4-NPs. Rat Macrophages (white blood cells) were used as the target.

本文重点研究了A4-NPs和J4-NPs。以大鼠巨噬细胞(白细胞)为靶点。

One class of endogenous NPs, the A4/J4-NPs, have been described, which are analogous in structure to the anti-inflammatory cyclopentenone PGs PGA2 and PGJ2.

已经描述了一类内源性NPs, A4/J4-NPs，其结构类似于抗炎环戊酮PGs PGA2和PGJ2。

These molecules contain an electrophilic α,β-unsaturated carbonyl moiety that readily forms adducts with cellular thiols via Michael addition.

这些分子包含亲电的α，β不饱和羰基部分，容易通过迈克尔加成与细胞硫醇形成加合物。

As the authors note, in vivo formation of such neuroprostanes occurs readily – 'Formation of highly reactive A-ring and J-ring isoprostane-like compounds (A4/J4-neuroprostanes) in vivo from docosahexaenoic acid' (Fam et. al., 2002)

作者指出，这种神经前列腺素在体内很容易形成——“在体内由二十二碳六烯酸形成高度反应的a环和j环类异前列腺素化合物(A4/ j4神经前列腺素)”(Fam et al.， 2002)。

Because of their structural similarities to anti-inflammatory cyclopentenone PGs and IsoPs, we hypothesize that A4/J4-NPs exert anti-inflammatory actions and may mediate some of the bioactivity of DHA.

由于A4/J4-NPs与抗炎环戊酮PGs和IsoPs的结构相似，我们推测A4/J4-NPs具有抗炎作用，并可能介导DHA的一些生物活性。

0.5mM showed 25% inhibition. 1.0mM showed about 40% inhibition, 5mM showed almost 90% inhibition. Looks like we've got a linear effect going on here. More A4-NP, less iNOS and COX-2.

0.5mM的抑制率为25%。1.0mM的抑制率约为40%，5mM的抑制率约为90%。看起来这里有一个线性效应。更多的A4-NP，更少的iNOS和COX-2。

A4-NP also completely blocked NF-κB activation induced by the pro-inflammatory cytokines TNFα and IL-1β (Fig. 3B)

LPS, TNFα, and IL-1β activate NF-κB via distinct receptors and signaling pathways, which converge at the level of IκB kinase complex (IKK) activation

This finding demonstrates that A4-NP-mediated inhibition of NF-κB signaling does not occur at the receptor level.

A4-NP还完全阻断了促炎细胞因子TNFα和IL-1β诱导的NF-κB活化(图3B)

LPS、TNFα和IL-1β通过不同的受体和信号通路激活NF-κB，这些受体和信号通路集中于IκB激酶复合物(IKK)的激活水平。

这一发现表明，a4 - np介导的NF-κB信号抑制并不发生在受体水平。

NF-κB-mediated transcription requires translocation of p50/p65 heterodimers from the cytosol to the nucleus.

Immunostaining of RAW264.7 cells demonstrated NF-κB p65 confined to the cytoplasm, whereas LPS stimulation resulted in intense nuclear p65 accumulation after 30 min (Fig. 4A). Phosphorylation of IκBα at Ser-32 and -36 by IKK precedes its dissociation from p65/p50 and proteasomal degradation.

LPS caused pronounced IκBα phosphorylation at 10 min, which was almost completely abrogated by A4-NP (Fig. 4C). A4-NP also substantially inhibited IκBα phosphorylation after 20 min of LPS exposure.

These results, coupled with the ability of A4-NP to suppress NF-κB activation triggered by TNFα and IL-1β, suggest that A4-NP may inhibit NF-κB signaling at the level of the IKK complex.

Mutation of IKKβ Cysteine 179 Impairs the Ability of A4-NPs to Inhibit NF-κB Signaling.

RAW264.7细胞的免疫染色显示，NF-κB p65局限于细胞质，而LPS刺激在30分钟后导致核p65的强烈积累(图4A)。IKK可使IκBα在Ser-32和-36位点磷酸化，使其从p65/p50解离并降解蛋白酶体。

LPS可引起IκBα在10min时的显著磷酸化，而这一磷酸化几乎被A4-NP完全消除(图4C)。在LPS处理20分钟后，A4-NP也显著抑制IκBα磷酸化。

这些结果，再加上A4-NP抑制TNFα和IL-1β触发的NF-κB激活的能力，表明A4-NP可能在IKK复合物水平上抑制NF-κB信号通路。

Cys-179 in IKKβ contains a thiol group susceptible to Michael adduction, and cyclopentenone PGs are known to inhibit NF-κB signaling via adduction of this residue.

Overexpression of WT or mutant C179A IKKβ caused a marked increase in NF-κB-luc reporter activity in HEK293 cells in the absence of LPS signaling. A4-NP suppressed this increase significantly by a mean of 62% in WT IKKβ cells (p < 0.05) but did not significantly decrease NF-κB activation in C179A mutant cells.

IKKβ中的Cys-179包含一个易受Michael内收的硫醇基团，环戊酮PGs已知可通过该残基的内收抑制NF-κB信号通路。

在缺乏LPS信号的情况下，过表达WT或突变C179A IKKβ可导致HEK293细胞NF-κB-luc报告因子活性的显著增加。在WT IKKβ细胞中，A4-NP显著抑制了这种增加，平均抑制率为62% (p < 0.05)，但在C179A突变细胞中NF-κB的活化没有显著降低。

•Oxidation of DHA Increases A4/J4-NP Content and Anti-inflammatory Potency in Parallel

As shown in Fig. 6A, treatment with unoxidized DHA did not affect LPS-induced nitrite production in RAW cells in the acute setting (30 min of preincubation), whereas oxidized DHA (which had been subjected to 10 h of oxidation with 5 mm AAPH) caused a dose-dependent inhibition of nitric oxide production.

oxDHA also inhibited LPS-stimulated NF-κB reporter activity at similar concentrations in immortalized murine macrophages (Fig. 6B)

oxDHA subjected to solid phase extraction on a C18 SepPak, which removes unoxidized DHA from the mixture but preserves A4/J4-NPs, retained its anti-inflammatory potency.

如图6所示,治疗未氧化的DHA并不影响LPS-induced原始细胞急性亚硝酸盐生产设置预孵化(30分钟),而氧化DHA(曾受到10 h与5毫米AAPH)氧化剂量依赖性抑制一氧化氮引起的生产。

在相同浓度下，oxDHA也能抑制lps刺激的NF-κB报告细胞活性(图6B)。

在C18 SepPak上进行固相萃取，从混合物中去除未氧化的DHA，但保留了A4/J4-NPs，保留了其抗炎效力。

•Bioactivity of Both A4-NPs and oxDHA Is Independent of PPARγ and Is Eliminated by Chemical Reduction or Conjugation to GSH.

4-nps和oxDHA的生物活性都不依赖于PPARγ，并通过化学还原或与GSH结合而消除。

We observed that two molecularly distinct PPARγ receptor antagonists, GW9662 and T0070907, used at concentrations well above their respective IC50 values, failed to inhibit the anti-inflammatory effects of A4-NP (Fig. 7A), suggesting that PPARγ is not crucially involved

We also observed that PPARγ antagonists had no effect on the anti-inflammatory effect of oxDHA.

我们观察到，两种分子上截然不同的PPARγ受体拮抗剂，GW9662和T0070907，在其浓度远高于各自的IC50值时，未能抑制A4-NP的抗炎作用(图7A)，这表明PPARγ并不是关键因素

Incubation of RAW cells with 10 μm A4-NP for 1 h also did not alter cellular levels of GSH (data not shown), demonstrating that A4-NPs mechanism of action is not reliant on the depletion of intracellular GSH

Taken together, these results suggest that the bioactivity of A4-NP is mediated largely by its chemical reactivity and ability to form thiol adducts with proteins,

This is consistent with a role for cyclopentenone NPs in the anti-inflammatory effect of oxDHA, although the inactivation of other reactive compounds present in the oxDHA mixture cannot be ruled out.

用10 μm A4-NP孵育RAW细胞1小时也没有改变细胞内谷胱甘肽水平(数据未显示)，这表明A4-NP的作用机制并不依赖于细胞内谷胱甘肽的消耗。

综上所述，这些结果表明，A4-NP的生物活性主要是由其化学反应性和与蛋白质形成硫醇加合物的能力介导的，这与环戊酮NPs在oxDHA抗炎作用中的作用是一致的，尽管不能排除oxDHA混合物中存在的其他活性化合物的失活。

•A4/J4-NPs Are Found Abundantly in Human Brain Specimens from Patients with Alzheimer Disease

We obtained frontal cortex brain samples from pathologically confirmed AD and age-matched control patients and examined levels of A4/J4-NPs by GC/MS.

As shown in Fig. 8, esterified levels of A4/J4-NPs were ∼3-fold greater in AD brain than controls. The average level of A4/J4-NPs in an AD brain sample was 295 ng/g brain tissue, which roughly converts to 950 nM A4/J4-NPs.

500 nM A4-NP exerted significant anti-inflammatory effects in our cell culture system, showing that A4/J4-NPs are found in biologically relevant concentrations in humans in vivo.

我们从病理证实的AD患者和年龄匹配的对照组患者的额叶皮质脑样本中提取A4/J4-NPs，并用GC/MS检测A4/J4-NPs水平。

如图8所示，AD患者大脑中A4/J4-NPs的酯化水平比对照组高出约3倍。AD脑组织中A4/J4-NPs的平均水平为295 ng/g脑组织，大致转换为950 nM A4/J4-NPs。

500nm A4- np在我们的细胞培养体系中具有显著的抗炎作用，表明A4/ j4 - np在人体内存在生物学相关浓度。

OK, so that was a lot of details … but I only bring them up because I think they are exactly the details supporting why suppression of NF-kB and other “inflammatory” agents is a BAD thing. This is precisely why oxidised DHA and it's resultant products can be considered to be an “immune system suppressent”.

好了，这就是很多细节……但我之所以提到它们，是因为我认为它们正是支持为什么抑制NF-kB和其他“炎症”因子是一件坏事的细节。这就是为什么氧化的DHA和它产生的产品可以被认为是“免疫系统抑制”。

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16/12/2015-tyw-Docosahexaenoic Acid (DHA)（1）