科学家证明器官再生需要多种细胞共同参与

FreeCell

; A4 D2 d/ U3 t9 C1 Z

; J0 J9 n; j' t  X. r+ ]Zebrafish Regrow Fins Using Multiple Cell Types, Not Identical Stem Cells+ L6 X6 z1 F6 G6 r2 c+ A& }
斑马鱼用多种细胞生成鳍片，而不是一种干细胞
- o0 D3 P5 J2 l& _2 e) h  `! |4 w* W1 X! p- H+ ]0 s: I0 \
用什么材料可以再生一个手臂？ 生物学家一直以为斑马鱼和蝾螈可以用干细胞再生任何组织，但是最新的研究表明需要多种细胞参与完成器官再生，至少在斑马鱼中是这样...7 g2 O. f* E, @1 q7 G" E
* Y! ]- h) a( r* G7 H  m3 T$ t+ J
ScienceDaily (May 16, 2011) — What does it take to regenerate a limb? Biologists have long thought that organ regeneration in animals like zebrafish and salamanders involved stem cells that can generate any tissue in the body. But new research suggests that multiple cell types are needed to regrow the complete organ, at least in zebrafish.
: l& M1 h+ R" v  O. N( J- B! U--------------------------------------------------------------------------------
* Y2 N/ T' Z; o$ A. A% }7 c5 c( _Researchers at Washington University School of Medicine in St. Louis have shown that cells capable of regenerating a zebrafish fin do not revert to stem cells that can form any tissue. Instead, the individual cells retain their original identities and only give rise to more of their own kind.
, i% c3 V& c" X+ J
4 P/ z3 I3 C* ^5 ?! [The findings support a recent shift in how biologists understand organ regeneration in organisms such as salamanders and zebrafish. Understanding regeneration in model organisms gives hope that it may one day be possible for amputees to regrow limbs or for heart attack patients to regrow healthy heart muscle.# B, [6 {4 L7 ]/ ~! h
8 U; d9 v, u9 @* J+ u
"Limb regeneration has long captured people's imaginations," says Stephen L. Johnson, PhD, associate professor of genetics at the School of Medicine. "Traditionally, when people have looked at how a limb regenerates, they see a group of cells forming at the amputation site and the cells all look the same. So they've imagined that these cells have lost their identities and can become anything else. Our results show that this is not the case in the zebrafish fin. And there is mounting evidence that this is not the case in the salamander limb."- T/ n8 [1 L. j2 g! y7 W' r4 r
; c- O, m1 }$ O4 b% x% Q7 _0 ~9 f
The study appears online May 16 in Developmental Cell.
) U; f% u. M, K( C8 zWhen a zebrafish loses its fin, a special group of cells forms on the remaining stump. These cells, which appear identical to one another, regrow the entire limb, complete with all cell types required for a complex organ. This has suggested that these cells may be "pluripotent" stem cells, capable of forming almost every tissue in the body.8 f0 O% u7 S; m! A. T
6 d& j5 n# [7 w) y  x
To determine if this was indeed the case, Johnson and postdoctoral research associate Shu Tu, PhD, who did this work for her doctoral thesis, used genetic techniques to label individual cells in the stump with a fragment of DNA that makes the cells glow green.
$ t2 ^3 y  @6 Q( e# t$ K* _1 G7 U; C7 X  l6 S  `
When a cell divides, it copies its DNA so that each daughter cell has a complete set of genetic material. Since Johnson and Tu's label is inserted into the cell's DNA, the cells also duplicate the label and pass it on to each daughter cell. By simply observing which cells glow green, Johnson and Tu could track the subsequent daughter cells and determine what cell types they become.
3 v1 F: \$ }$ n, z" y; Q1 {
" T  T0 z4 ^" m- w3 fFor example, they saw that when they had glowing skin cells in the stump, only skin cells glowed in the regenerated limb. Likewise, when a nerve cell glowed in the stump, only nerve cells glowed in the regenerated limb. In other words, they saw no evidence that a skin cell glowing in the stump could give rise to a nerve cell glowing later in the fin's development or regeneration.- c6 k$ x& s% I5 q7 w( v

& u/ n5 G8 `# E: s/ @. u, XUsing this technique, Johnson and Tu identified nine separate cell lineages present at the end of the stump that contribute to forming the fin's skin, nerves, pigment, blood vessels, bone and immune cells.4 C- M0 N6 n8 q/ j% |. |

% B9 j1 |3 K2 sJohnson points out possible implications for future regenerative medicine in humans.
' y$ ^( E6 v% Q. n& w; W  a5 t1 ]: a: q. P
"This is evidence that we can't necessarily do regenerative medicine by plopping in generalized stem cells," he says. "The key may be to induce the cells that are already there to grow again. We need to understand and account for every cell lineage and then convince them to play ball together."5 [0 L3 q  c  D. S# k0 m% {
- I2 ?/ j( [) k0 l' }
“这些证据表明我们不能只依赖通常意义上的的干细胞来完成再生医学使命，问题的关键也许在于诱导机体的内源性细胞恢复生长能力，我们需要很好地了解每种细胞谱系的特性，让他们共同参与这个“再生”游戏。“1 Z( P, k) @7 p/ E4 {# u
6 |: |2 Y, m# t# v
This work was funded by the National Institutes of Health (NIH).+ `5 n" T  k2 ]
--------------------------------------------------------------------------------
* s/ V" o$ ^' z) v' a# q) ZStory Source:
3 U# I3 I( ^5 I6 w: a& vThe above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Washington University School of Medicine. The original article was written by Julia Evangelou Strait.; _% e" H2 g2 \1 F
--------------------------------------------------------------------------------  Z; @  A$ x/ S% v
Journal Reference:
. q6 t/ ?! k5 q; c4 _Shu Tu, Stephen L. Johnson. Fate Restriction in the Growing and Regenerating Zebrafish Fin. Developmental Cell, Volume 20, Issue 5, 725-732, 17 May 2011 DOI: 10.1016/j.devcel.2011.04.013

张也行

很有意思，感谢分享

luoziwei

本来就是，器官本身就包含了多种不同的细胞

pauldong

呵呵，这个需要证明吗，除了单细胞动物，那个器官不包括很多种细胞的协调作用

wys7416

器官的发生本省就是多细胞的协同结果，关键是要了解他们如何协同的，如何发生和相互作用，从而为我们组织器官再造来服务，其实还有一个问题，可能这些细胞原先来源于一个干细胞，慢慢发展成一个多细胞芽基，再分化形成多种细胞类型，最后形成一个组织器官

hyde

个人觉得可能多种干细胞完成组织修复会比较容易，或者更符合某些潜在的发育规律。# ?  U- [! ~9 t7 u$ K3 K
个人觉得在现在的知识科技水平上无法完成的事并不一定不能完成……只是有没有能力去把它完成…………