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大家好
Hello,

我是 Ludovic Tailleux
I am Ludovic Tailleux.

我在巴斯德研究院工作
I work at the Pasteur Institute

研究结核病期间宿主和病原体之间的
and I work on host-pathogen interactions

相互作用
during tuberculosis.

今天
Today,

我将谈论结核分枝杆菌
I will talk about how Mycobacterium tuberculosis

如何破坏先天性免疫反应
subverts the innate immune response

重点是人体巨噬细胞
with particular emphasis on the human macrophages.

结核病根本上是肺部疾病
Tuberculosis is primarily a pulmonary disease

当含有结核分枝杆菌的液滴吸入肺泡时
but it is initiated when Mycobacterium tuberculosis containing droplets

肺结核就开始了
are inhaled into the alveoli.

巨噬细胞是结核分枝杆菌的主要靶细胞
Macrophages are the main cell target of Mycobacterium tuberculosis.

感染后
Upon infection,

这些细胞可以分泌细胞因子和趋化因子
these cells can secrete cytokines and chemokines

从而使一些炎症细胞聚集
that will allow the recruitment of some inflammatory cells.

另一种在结核病早期阶段发挥关键作用的
Dendritic cells are another cell type that plays a key role

细胞是树突状细胞
during the early stages of tuberculosis.

这些细胞可以被感染
These cells can be infected

也可以吞噬分枝杆菌抗原
or they can phagocytose Mycobacterial antigens.

激活后
Upon activation,

这些细胞迁移到引流淋巴结
these cells migrate to the draining lymph nodes

并激活初始T细胞
and they activate naive T cells.

活化的T细胞迁移到感染部位
The activated T cells then migrate to the site of infection.

这种宿主反应导致肉芽肿的形成
This host response results in the formation of granulomas.

肉芽肿中央是被感染的巨噬细胞层
Granulomas consist in concentric layers of infected macrophages

周围是形成巨噬细胞和巨细胞
in the middle surrounded by forming macrophages, giant cells,

被活化的T细胞和B细胞包围
and surrounded by activated T and B cells.

在90％的病例中
In 90% of the cases,

这种反应足以控制感染
this response is sufficient to control the infection

不会患上结核病
and there is no disease, no tuberculosis.

但在10％的病例中
But in 10% of the cases,

细菌增殖
the bacteria proliferates,

巨噬细胞死亡
the macrophages die,

肉芽肿坏死
and the granulomas become necrotic,

释放细菌到细胞外介质
and release the bacteria in the extracellular medium.

要了解结核分枝杆菌如何进入宿主细胞
To understand how Mycobacterium tuberculosis enters the host cells,

了解分枝杆菌包膜的结构
it is very important to have an overview of the structure

是非常必要的
of the mycobacterial envelope.

分枝杆菌包膜有丰富的聚合物
The mycobacterial envelope is very rich in monoconjugates

由三个大分子组成 肽聚糖
and it consists in three macromolecules, the peptidoglycan,

阿拉伯半乳聚糖和被蛋白质
the arabinogalactan and the mycolic acids

和多糖包裹的霉菌酸
surrounded by a capsule of proteins and polysaccharides.

文献中已经描述过
Many Mtb receptors have been described

许多结核分枝杆菌（Mycobacterium tuberculosis，简称"Mtb"）受体
in the literature.

不出所料
Unsurprisingly,

结核分枝杆菌（Mycobacterium tuberculosis，简称"Mtb"）可以结合C型凝集素
Mtb can bind C-type lectins,

如甘露糖受体
such as the mannose receptor,

DC-SIGN
DC-SIGN,

mincle受体或dectin-1
mincle, or dectin-1.

其他受体有补体受体
The other receptors are the complement receptors,

CR3和CR4
the CR3 and CR4.

Fc-γ受体
The Fc-gamma receptors,

Toll样受体
the Toll-like receptors,

TLR-1,2,4,6
TLR-1, 2, 4, 6,

9
and 9,

清道夫受体
the scavenger receptors,

如MARCO和NOD样受体
such as MARCO, and the NOD-like receptors,

主要是NOD2
mainly NOD2.

了解结核分枝杆菌如何在巨噬细胞内
It is important to understand how Mycobacterium tuberculosis

生存和增殖是很重要的
survives and replicates inside the macrophages

因为巨噬细胞通常可以杀灭微生物
because macrophages can usually kill microbes.

所以结核分枝杆菌（Mycobacterium tuberculosis，简称"Mtb"）主要存在于液泡中
So Mtb resides mainly in a vacuole.

有些论文说结核分枝杆菌（Mycobacterium tuberculosis，简称"Mtb"）能从液泡中出来
There are some papers saying that Mtb can get out of these vacuoles

但其生物学意义还是有争议的
but the biological significance is still a matter of debate.

分枝杆菌吞噬体的一个主要特征
One major characteristic of the mycobacterial phagosome

是没有与溶酶体融合
is that there is no fusion with lysosomes

也没有酸化
and no acidification

酸化对酶活性非常重要
which is very important for the activity of mini enzymes.

为了说明这一现象
To illustrate this phenomenon,

我们用荧光蛋白标记的
we have infected human macrophages

结核分枝杆菌感染人类巨噬细胞
with a GFP expressing Mycobacterium tuberculosis,

如绿色字体所示
here in green..

对细胞染色是为了使用DAMP
And we stain the cell for DAMP.

DAMP是低pH有机体的探针
DAMP is a probe for low pH organisms.

这里
Here,

当我们用活菌感染细胞时
there is no colocalization between TB

细菌和DAMP之间没有共定位
and the DAMP when we infect the cells with live bacteria.

但是当我们用死菌感染时
But when we treat the cells with killed TB,

DAMP和细菌之间有一个完美的共定位
there is a perfect colocalization between the DAMP and the bacteria.

分枝杆菌吞噬体的pH约为6.3
The pH of the mycobacterial phagosome is around 6.3,

而溶酶体的pH约为5
whereas the pH of the lysosome is around 5.

已经发现了许多不同的因子
There are many different factors

可以抑制吞噬体成熟
that have been described to inhibit the phagosome maturation.

比如ESAT-6 / CFP-10蛋白质
Some of them are the ESAT-6/CFP-10 proteins,

SecA
the SecA,

PknG
the PknG,

脂阿拉伯甘露聚糖以及索状因子
the lipoarabinomannan,

索状因子也被称为海藻糖二霉菌酸酯
and the cord factor also called trehalose dimycolate.

此外
In addition,

为了抑制吞噬体成熟
to inhibit phagosome maturation,

结核分枝杆菌（Mycobacterium tuberculosis，简称"Mtb"）有不同的方法破坏巨噬细胞的反应
Mtb has developed different strategies to subvert

从而生存并扩散
the macrophage response to survive and to disseminate.

在下一张幻灯片中
In the next slide,

我会举三个例子
I will give you three examples:

自噬 宿主细胞死亡和血管生成
autophagy, host cell death and angiogenesis.

自噬是一个涉及细胞成分的破坏
Autophagy is a process that involves the destruction

和再循环的过程
and recycling of cellular components.

延伸来讲
By extension,

异体自噬是传染性粒子（如细菌和病毒）的
xenophagy is the autophagic degradation of infectious particles,

自噬降解
such as bacteria and viruses.

自噬始于隔离膜或吞噬泡的形成
Autophagy begins with the formation of an isolation membrane, or phagophore.

随着吞噬泡的扩大
As the phagophore expands,

细胞内容物
the intracellular contents,

如线粒体
such as mitochondria,

聚集的蛋白质
aggregated proteins,

细菌和病毒被分散开
bacteria and viruses, are unwrapped.

这导致自噬体的形成
It results in the formation of the autophagosomes.

这些自噬体可以与溶酶体融合并
These autophagosomes can fuse with lysosomes

形成自噬溶酶体
and form autolysosomes.

这时内容物被降解
At this step, the content is degraded.

结核分枝杆菌（Mycobacterium tuberculosis，简称"Mtb"）抑制自噬的方法
Mtb has developed different strategies to inhibit the autophagy

是抑制自噬体的形成
by inhibiting the formation of autophagosomes

或与溶酶体的融合
or the fusion with lysosomes.

但用维生素D处理
However, it is possible to induce autophagy

被结核分枝杆菌（Mycobacterium tuberculosis，简称"Mtb"）感染的巨噬细胞
in Mtb-infected macrophages

可能会诱发自噬
by treating the cell with vitamin D.

宿主细胞死亡是结核病的一个重要特征
Host cell death is an important feature of tuberculosis.

这里有一个肉芽肿
Here, you have a granuloma.

就像之前说的
As I told you before,

随着一步步的感染
as the infection progresses,

肉芽肿的中心慢慢坏死
the center of the granuloma becomes necrotic.

于是细胞发生凋亡或坏死
So the cell can die by apoptosis or by necrosis.

细胞凋亡是细胞的一种非炎症死亡方式
Apoptosis is a non-inflammatory type of cell death.

细胞内容物保留
And the intracellular contents

在被称为凋亡小体的囊泡内
are maintained inside vesicles called apoptotic bodies.

这些凋亡细胞或小体
These apoptotic cells or bodie

可以被其他细胞
s can be phagocytosed by other cells,

（如巨噬细胞或树突细胞）吞噬
such as macrophages or dendritic cells.

在这种情况下
Mtb, in this case,

结核分枝杆菌（Mycobacterium tuberculosis，简称"Mtb"）可以被胞吞作用杀死
can be killed by a phenomenon called efferocytosis

因为凋亡小体内的细菌
because TB inside apoptotic bodies

不能抑制与溶酶体的融合
cannot inhibit the fusion with lysosomes.

在一些其他情况下
In some other cases,

结核分枝杆菌（Mycobacterium tuberculosis，简称"Mtb"）可以存活并感染这些细胞
Mtb can survive and infect these cells.

坏死被定义为细胞裂解
Necrosis is defined as cell lysis.

血浆内容物释放到细胞外介质
It is very inflammatory because the plasmic content

非常容易引发炎症
is released in the extracellular medium.

它被识别为DAMP
And it is recognized as a DAMP,

一种损伤相关分子模式
a damage-associated molecular pattern.

结核分枝杆菌（Mycobacterium tuberculosis，简称"Mtb"）可以通过依赖ESX1的方式
Mtb can induce necrosis in macrophages

诱导巨噬细胞坏死
by an ESX1-dependent manner.

当巨噬细胞坏死时
When macrophages die by necrosis,

它们会在介质中释放出
they release in the medium bacteria

能感染许多细胞的细菌
that can infect many cells.

在最后一个例子中
In the last example,

我将讨论血管生成
I will talk about angiogenesis

展示结核分枝杆菌（Mycobacterium tuberculosis，简称"Mtb"）如何使用巨噬细胞进行传播
and I will show you how Mtb can use macrophages to disseminate.

几年前
A few years ago,

我们分析了感染结核分枝杆菌（Mycobacterium tuberculosis，简称"Mtb"）的巨噬细胞的转录组
we analyzed a transcriptome of Mtb-infected macrophages.

每个方块代表一个捐助者
Each square represents one donor,

一共有八个捐助者
so we have eight donors.

我们分析了感染后4 18
And we analyzed the transcriptome after 4,

和48小时的转录组
18 and 48 hours post-infection.

蓝色代表下调的基因
So blue represents downregulated genes

红色代表上调的基因
and red represents upregulated genes.

我们确定了约20个涉及血管生成的分子
We identified about 20 molecules involved in angiogenesis.

这些分子中有生长因子
These molecules are growth factors,

如血管内皮生长因子（vascular endothelial growth factor，简称“VEGF”）
such as the VEGF,

最有效的血管生成因子
with probably the most potent angiogenic factor.

也有金属蛋白酶
These molecules also include metalloproteinases,

一些基质金属蛋白酶
some MMPs.

这些酶参与细胞外基质的降解
These enzymes are involved in the degradation of the extracellular matrix

并且在血管发生的起始阶段起重要作用
and are important for the initiation of the angiogenesis.

还有一些涉及祖细胞募集的
And some chemokines which are involved

趋化因子
in the recruitment of progenitors.

结核病中血管生成的作用是什么呢
What could be the role of angiogenesis during tuberculosis?

我们假设它可能发挥形成转移酶作用
We hypothesize that it could play a similar role

就像在癌症中一样
as in cancer for the formation of metastases.

为了验证这一假设
To test this hypothesis,

我们用结核分枝杆菌感染小鼠
we infect mice with Mycobacterium tuberculosis

并用针对血管内皮生长因子（vascular endothelial growth factor，简称“VEGF”）受体2的抗体治疗它们
and we treat them with an antibody against the VEGF receptor 2.

每周治疗三次
We treat the mice three times a week

持续两周
for two weeks.

两周后杀死小鼠
After two weeks,we sacrifice the mice

并计算不同器官（如脾脏）内的
and we count the number of bacteria inside different organs,

细菌数量
such as the spleen.

如您所见
As you can see here,

当我们用抗血管内皮生长因子（vascular endothelial growth factor，简称“VEGF”）受体2治疗小鼠时
when we treat the mice with anti-VEGF receptor 2,

可以减少脾内细菌的传播
we can decrease the dissemination of the bacteria inside the spleen.

这项研究表明
So this study shows

结核分枝杆菌（Mycobacterium tuberculosis，简称"Mtb"）诱导新血管的形成
that Mtb induces the formation of new blood vessels

并利用这些血管在宿主体内传播
and uses these blood vessels to disseminate inside the host.

这个视频的总结如下
To conclude this video,

巨噬细胞是结核分枝杆菌的主要靶细胞
macrophages are the main cell target of Mycobacterium tuberculosis.

所以结核分枝杆菌主要存在于液泡中
So M.tuberculosis resides predominantly in a vacuole,

它不酸化
which does not acidify

不与溶酶体融合
and does not fuse with lysosomes.

它可以抑制自噬
It can inhibit autophagy.

也可以抑制细胞凋亡并诱导坏死
It can inhibit apoptosis and induce necrosis.

并且可以促进新血管的形成来传播
Finally, Mtb can exploit the formation of new blood vessels to disseminate.

感谢您的关注
Thank you for your attention.