撰文 | Fice

责编 | Lee

A new study shows how spike protein crosses the blood-brain barrier

More and more evidence is coming out that people with COVID-19 are suffering from cognitive effects, such as brain fog and fatigue.

一项新的研究揭示了刺突蛋白是如何穿过血脑屏障的

越来越多的证据表明，COVID-19患者存在脑雾、脑疲劳等认知影响。

And researchers are discovering why. The SARS-CoV-2 virus, like many viruses before it, is bad news for the brain. In a study published Dec.16 in Nature Neuroscience, researchers found that the spike protein, often depicted as the red arms of the virus, can cross the blood-brain barrier in mice.

研究人员正在寻找原因。SARS-CoV-2病毒和之前的许多病毒一样，对大脑来说是个坏消息。在12月16日发表在《自然神经科学》(Nature Neuroscience)杂志上的一项研究中，研究人员发现，通常被描述为病毒红臂的刺突蛋白可以穿过小鼠的血脑屏障。

This strongly suggests that SARS-CoV-2, the cause of COVID-19, can enter the brain.

这强烈表明，引起COVID-19的SARS-CoV-2可以进入大脑。

The spike protein, often called the S1 protein, dictates which cells the virus can enter. Usually, the virus does the same thing as its binding protein, said corresponding author William A. Banks, a professor of medicine at the University of Washington School of Medicine and a Puget Sound Veterans Affairs Healthcare System physician and researcher. Banks said binding proteins like S1 usually by themselves cause damage as they detach from the virus and cause inflammation.

刺突蛋白通常被称为S1蛋白，它决定了病毒可以进入哪些细胞。通常，病毒和它的结合蛋白做同样的事情，通讯作者威廉·a·班克斯说，他是华盛顿大学医学院的医学教授，也是普吉特Sound退伍军人事务医疗保健系统的医生和研究员。班克斯说，像S1这样的结合蛋白在脱离病毒并引起炎症时，通常本身就会造成损害。

"The S1 protein likely causes the brain to release cytokines and inflammatory products," he said.

“S1蛋白可能导致大脑释放细胞因子和炎症产物，”他说。

In science circles, the intense inflammation caused by the COVID-19 infection is called a cytokine storm. The immune system, upon seeing the virus and its proteins, overreacts in its attempt to kill the invading virus. The infected person is left with brain fog, fatigue and other cognitive issues.

在科学界，COVID-19感染引起的强烈炎症被称为细胞因子风暴。免疫系统在看到病毒及其蛋白质后，在试图杀死入侵的病毒时反应过度。感染者会出现脑雾、疲劳和其他认知问题。

Banks and his team saw this reaction with the HIV virus and wanted to see if the same was happening with SARS CoV-2.

班克斯和他的团队在艾滋病毒上看到了这种反应，并想看看SARS CoV-2是否也发生了同样的情况。

Banks said the S1 protein in SARS-CoV2 and the gp 120 protein in HIV-1 function similarly. They are glycoproteins -- proteins that have a lot of sugars on them, hallmarks of proteins that bind to other receptors. Both these proteins function as the arms and hand for their viruses by grabbing onto other receptors. Both cross the blood-brain barrier and S1, like gp120, is likely toxic to brain tissues.

班克斯说，SARS-CoV2中的S1蛋白和HIV-1中的gp 120蛋白功能相似。它们是糖蛋白——一种含有大量糖的蛋白质，是与其他受体结合的蛋白质的标志。这两种蛋白质通过抓住其他受体来充当病毒的手臂和手。无论是通过血脑屏障还是S1，比如gp120，都可能对脑组织有毒。

"It was like déjà vu," said Banks, who has done extensive work on HIV-1, gp120, and the blood-brain barrier.

“这就像曾经（déjà vu），”班克斯说，他在HIV-1、gp120和血脑屏障方面做了大量工作。

The Banks' lab studies the blood-brain barrier in Alzheimer's, obesity, diabetes, and HIV. But they put their work on hold and all 15 people in the lab started their experiments on the S1 protein in April. They enlisted long-time collaborator Jacob Raber, a professor in the departments of Behavioral Neuroscience, Neurology, and Radiation Medicine, and his teams at Oregon Health & Science University.

班克斯的实验室研究阿尔茨海默病、肥胖、糖尿病和艾滋病的血脑屏障。但他们暂时搁置了这项工作，实验室的所有15人在4月份开始了S1蛋白质的实验。他们招募了长期合作的行为神经科学、神经学和放射医学系教授Jacob Raber和他在俄勒冈健康与科学大学的团队。

The study could explain many of the complications from COVID-19.

这项研究可以解释COVID-19的许多并发症。

"We know that when you have the COVID infection you have trouble breathing and that's because there's infection in your lung, but an additional explanation is that the virus enters the respiratory centers of the brain and causes problems there as well," said Banks.

班克斯说:“我们知道，当你感染了新冠病毒，你会呼吸困难，这是因为你的肺部受到了感染，但另一种解释是，病毒进入了大脑的呼吸中枢，也在那里引发了问题。”

Raber said in their experiments transport of S1 was faster in the olfactory bulb and kidney of males than females. This observation might relate to the increased susceptibility of men to more severe COVID-19 outcomes.

雷波说，在他们的实验中，S1在男性嗅球和肾脏中的转运速度比女性快。这一观察结果可能与男性对更严重COVID-19结果的易感性增加有关。

As for people taking the virus lightly, Banks has a message:

对于那些对病毒掉以轻心的人，班克斯给出了一个信息:

"You do not want to mess with this virus," he said. "Many of the effects that the COVID virus has could be accentuated or perpetuated or even caused by virus getting in the brain and those effects could last for a very long time."

他说:“你不会想搅乱这种病毒的。”“新冠病毒的许多影响可能会加重或延续，甚至是病毒进入大脑引起的，这些影响可能会持续很长时间。”

This study was partially supported by a National Institute on Aging-funded COVID-19 supplement to a shared RF1 grant of Banks and Raber.

本研究部分由国家老龄问题研究所资助的COVID-19补充基金支持，该补充基金由银行和Raber共同提供RF1资助。