医学翻译 中英翻译 干细胞
2021-01-19 17:45:43

Molecule guides stem cells to damaged brain tissue


Researchers altered a molecule that is naturally produced by the body to safely guide stem cells to damaged brain tissue.


Mice with a fatal brain disease had delayed onset of symptoms and improved survival when given the new molecule and neural stem cells.


With further development, the approach may have applications for human disease.



Neural stem cells maturing into brain cells called astrocytes (yellow). Sanford Burnham Prebys Medical Discovery Institute


Stem cells are part of the body’s repair system. They have the potential to replace specialized cells—such as muscle cells, blood cells, and brain cells—that have been damaged by injury or disease.


The amount of repair that stem cells do in the adult body is limited. Researchers have been looking for ways to draw more stem cells to injured areas and focus their work. Harnessing the body’s healing mechanisms in this way is called regenerative medicine.


To attract stem cells to injured tissues, the body naturally releases chemicals called chemokines. But chemokines also cause inflammation, and long-term inflammation in the brain and body can cause more harm than good. Therefore, it hasn’t been considered safe to use natural chemokines for regenerative medicine.


A research team led by Dr. Evan Snyder from the Sanford Burnham Prebys Medical Discovery Institute tested whether they could engineer a natural chemokine to attract stem cells without causing inflammation. They altered a chemokine called CXCL12, which can draw neural stem cells to sites of injury or disease in the brain and central nervous system. CXCL12 binds to a receptor called CXCR4 on the surface of these stem cells.

由桑福德·伯纳姆·普雷姆斯医学发现研究所的埃文·斯奈德(Evan Snyder)博士领导的研究小组测试了它们是否可以工程化天然趋化因子以吸引干细胞而不引起炎症。他们改变了一种称为CXCL12的趋化因子,它可以将神经干细胞吸引到大脑和中枢神经系统的损伤或疾病部位。 CXCL12与这些干细胞表面上称为CXCR4的受体结合。

When activated, CXCR4 can signal different reactions within the cells. Using computational methods, the researchers optimized the part of CXCL12 that initially binds CXCR4. They then replaced the portion that triggers CXCR4 to boost inflammation. The work was funded in part by NIH’s National Institute of General Medical Sciences (NIGMS). Results were published on November 20, 2020,in Proceedings of the National Academy of Sciences.


After testing different versions of the molecule in laboratory experiments, the team focused on one called SDV1a. SDV1a strongly encouraged neural stem cells to migrate towards its signal without activating genes associated with inflammation. Instead, it activated genes involved in tissue repair.

在实验室实验中测试了该分子的不同版本之后,该团队专注于开发一种名为SDV1a的分子。 SDV1a强烈鼓励神经干细胞向其信号迁移而不激活与炎症相关的基因。相反,它激活了参与组织修复的基因。

The team next tested their new molecule in the brains of healthy mice. When they injected SDV1a into one side of the brain and neural stem cells into the other, the cells migrated to the side with SDV1a. Both SDV1a and the stem cells remained active in the brain for weeks. The mice showed no inflammation or other side effects from treatment.

接下来,研究小组在健康小鼠的大脑中测试了他们的新分子。当他们将SDV1a注射到大脑的一侧,而将神经干细胞注射到另一侧时,这些细胞就会与SDV1a一起迁移到一侧。 SDV1a和干细胞在大脑中都保持活跃数周。小鼠从治疗中未显示出炎症或其他副作用。

Finally, the researchers gave the combination of SDV1a and neural stem cells to mice with a deadly degenerative brain disorder. SDV1a was injected into the brain’s cortex, and stem cells were implanted into ventricles—brain cavities filled with cerebrospinal fluid.


The stem cells spread throughout the brain and produced new neurons. Mice that received the treatment had slower onset of disease symptoms and lived longer.


“The ability to instruct a stem cell where to go in the body or to a particular region of a given organ is the Holy Grail for regenerative medicine,” Snyder says. “Now, for the first time ever, we can direct a stem cell to a desired location and focus its therapeutic impact.”

斯奈德说:指示干细胞进入人体或特定器官特定部位的能力是再生医学的圣杯。” “现在,有史以来第一次,我们可以将干细胞定向到所需位置并集中其治疗作用。

The team is now testing their approach in a mouse model of amyotrophic lateral sclerosis (ALS). Similar strategies may help improve stem cell therapy for spinal cord injury and stroke, as well as boost repair in other parts of the body.


—by Sharon Reynolds

莎朗·雷诺兹(Sharon Reynolds






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