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发信人: Marble (小石头哥哥), 信区: Biology
标 题: MCBJC(Neurogenesis/adult neural stem cell)
发信站: The unknown SPACE (Mon Apr 7 14:13:53 2003), 站内信件
this Nature paper (2002 417:39) addressed the mechanisms that
control fate of neural stem cells. astrocytes have been
thought merely as supportive cells in the central nervous
system, however, this work has demonstrated that astrocytes
isolated from adult hippocampus, but not spinal chord,
promoted neurogenesis (i.e., neuron fate) of the adult neural
stem cells in cell culture. this study has highlighted the
effects of the environment on the specification of stem cells.
for stem cell research, many labs try to identify the key
features for cells that have "stemness", and how they could
be induced to differentiate into different lineages, and
whether different lineages could "transdifferentiate". it is
rather new area with many things unknown, and even experiments
that had doubt on previously published data could get onto
top journals.
my questions for this paper:
1. what are the methodology they used to study differentiation
of neural stem cells? do you think there might be flaw for such
study (for example, primarily in vitro cell culture; counting
cells with differentiation marker really means that the cells
have differentiated into functional states)?
2. they proposed that cell-attached and diffusible factors from
astrocytes are essential to the neurogenesis of adult stem
cells. how would you like to identify and characterize such
factors biochemically and genetically?
3. btw, Dr. Song also had a publication on Nat Neuro 2002
5:438 in which he demonstrated that these stem cells had
functionally integrated into the system using electrophysiology.
i would think that in vivo transplantation and a long-term
project chasing the fate of the neural stem cells would be
more convincing.
--
※ 修改:．Marble 于 Apr 7 16:15:19 修改本文．[FROM: 128.118.]
※ 来源:．The unknown SPACE bbs.mit.edu．[FROM: 128.118.]
发信人: macromind (星雨), 信区: Biology
标 题: Re: MCBJC(Neurogenesis/adult neural stem cell)
发信站: The unknown SPACE (Mon Apr 7 20:26:27 2003), 站内信件
【 在 Marble (小石头哥哥) 的大作中提到: 】
: this Nature paper (2002 417:39) addressed the mechanisms that
: control fate of neural stem cells. astrocytes have been
: thought merely as supportive cells in the central nervous
: system, however, this work has demonstrated that astrocytes
: isolated from adult hippocampus, but not spinal chord,
: promoted neurogenesis (i.e., neuron fate) of the adult neural
: stem cells in cell culture. this study has highlighted the
: effects of the environment on the specification of stem cells.
: for stem cell research, many labs try to identify the key
: features for cells that have "stemness", and how they could
: be induced to differentiate into different lineages, and
: whether different lineages could "transdifferentiate". it is
: rather new area with many things unknown, and even experiments
: that had doubt on previously published data could get onto
: top journals.
: my questions for this paper:
: 1. what are the methodology they used to study differentiation
: of neural stem cells? do you think there might be flaw for such
: study (for example, primarily in vitro cell culture; counting
: cells with differentiation marker really means that the cells
: have differentiated into functional states)?
To study NSC differentiation, GFP and differentiation maker can be used in
vitro, which is relatively easy. In vivo differentiation
studies usually adopt 2 strategies: transplantation or retroviral injection
to trace the progenies of NSC. People have done that,
showing that different cell types are generated, but it's really hard to say
these different progenies are from the same SINGLE
ancestor. Till now, I think there is still NO convicing evidence to demostra
te NSC existence in vivo. Some people even think only
progenitors exist over there, and astrocytes are the bona fide stem cells.
You made a very good point arguing that those markers are not necessarily id
entities of specific cell types. Actually as many labs
show, MAPab can also react with astrocytes and/or oligodendrocytes. But in t
his experiment, MAPab+ cells are certainly not
GFAP+ or RIP+, suggesting that MAPab+ are mostly, although not exclusively,
neurons.
: 2. they proposed that cell-attached and diffusible factors from
: astrocytes are essential to the neurogenesis of adult stem
: cells. how would you like to identify and characterize such
: factors biochemically and genetically?
Biochemically, we can purify the factors from the conditioned medium and to
assay their activity to regulate neurogenesis. Actually
the same lab identified CCg which is required for NSC proliferation and neur
ogenesis. Obviously there are many other factors remain
unidentified. Microarray to compare SC- and Hippacampal astrocyte may get a
lot of information. I don't know and have interests in
listening your genetical approches.
: 3. btw, Dr. Song also had a publication on Nat Neuro 2002
: 5:438 in which he demonstrated that these stem cells had
: functionally integrated into the system using electrophysiology.
: i would think that in vivo transplantation and a long-term
: project chasing the fate of the neural stem cells would be
: more convincing.
In vivo tracing of the NSC fates by either transplantation or retroviral mak
er have been done previously. But those experiments are
hard to reveal the active regulatory role of astrocytes, because of the hete
rogenous nature of cell composition in neurogenic region of
DG. The massive astrocytic background in culture might, I guess, conveys som
e information of lack of functional neurons, thus
instructs NSC (probably SOME astrocytes themselves) to become neurons.
--
※ 来源:．The unknown SPACE bbs.mit.edu．[FROM: 162.129.]
发信人: Marble (小石头哥哥), 信区: Biology
标 题: Re: MCBJC(Neurogenesis/adult neural stem cell)
发信站: The unknown SPACE (Wed Apr 9 17:20:49 2003), 站内信件
【 在 macromind (星雨) 的大作中提到: 】
: 【 在 Marble (小石头哥哥) 的大作中提到: 】
: : this Nature paper (2002 417:39) addressed the mechanisms that
: : control fate of neural stem cells. astrocytes have been
: : thought merely as supportive cells in the central nervous
: : system, however, this work has demonstrated that astrocytes
: : isolated from adult hippocampus, but not spinal chord,
: : promoted neurogenesis (i.e., neuron fate) of the adult neural
: : stem cells in cell culture. this study has highlighted the
: : effects of the environment on the specification of stem cells.
: : for stem cell research, many labs try to identify the key
: : features for cells that have "stemness", and how they could
: : be induced to differentiate into different lineages, and
: : whether different lineages could "transdifferentiate". it is
: : rather new area with many things unknown, and even experiments
: : that had doubt on previously published data could get onto
: : top journals.
: : my questions for this paper:
: : 1. what are the methodology they used to study differentiation
: : of neural stem cells? do you think there might be flaw for such
: : study (for example, primarily in vitro cell culture; counting
: : cells with differentiation marker really means that the cells
: : have differentiated into functional states)?
: To study NSC differentiation, GFP and differentiation maker can be used in
: vitro, which is relatively easy. In vivo differentiation
: studies usually adopt 2 strategies: transplantation or retroviral injection
: to trace the progenies of NSC. People have done that,
: showing that different cell types are generated, but it's really hard to say
: these different progenies are from the same SINGLE
: ancestor. Till now, I think there is still NO convicing evidence to demostra
: te NSC existence in vivo. Some people even think only
: progenitors exist over there, and astrocytes are the bona fide stem cells.
: You made a very good point arguing that those markers are not necessarily id
: entities of specific cell types. Actually as many labs
: show, MAPab can also react with astrocytes and/or oligodendrocytes. But in t
: his experiment, MAPab+ cells are certainly not
: GFAP+ or RIP+, suggesting that MAPab+ are mostly, although not exclusively,
: neurons.
: : 2. they proposed that cell-attached and diffusible factors from
: : astrocytes are essential to the neurogenesis of adult stem
: : cells. how would you like to identify and characterize such
: : factors biochemically and genetically?
: Biochemically, we can purify the factors from the conditioned medium and to
: assay their activity to regulate neurogenesis. Actually
: the same lab identified CCg which is required for NSC proliferation and neur
very good points. while you have listed so many answers that
others could not participate, i have to ban you. hehe.
as for the functional analysis, i think a long-term in vivo
observation is important if the final goal is for clinics.
however, when i talked with Fred Gage, he did not seem to be
interested; one reason i think is that stem cell research is
not welcomed by the politicians and its clinical prospect is
still shaddowed. btw, there are too many unknowns, and it is
still not applicable for such bold exploration. to find the
molecules that are essential to astrocyte promoted neurogenesis,
i have also thought about analysis of the difference b/w
spinal chord and hippocampus. besides microarray (for total
RNA and polysomal RNA that is termed to being translated ),
i would like to screen for pharmcological molecules that
interrupt with this process (too risky). biochemical analysis
of the diffusible factors is quite important, as you have
mentioned. it may be interesting to fractionate such peptides
or hormones and test the effects on NSC, and determine the
dosage response. meanwhile, i would consider investigation
of genetically modified neural stem cell and astrocytes,
particularly if the expression of certain key genes could
be controlled during this process.
: ogenesis. Obviously there are many other factors remain
: unidentified. Microarray to compare SC- and Hippacampal astrocyte may get a
: lot of information. I don't know and have interests in
: listening your genetical approches.
: : 3. btw, Dr. Song also had a publication on Nat Neuro 2002
: : 5:438 in which he demonstrated that these stem cells had
: : functionally integrated into the system using electrophysiology.
: : i would think that in vivo transplantation and a long-term
: : project chasing the fate of the neural stem cells would be
: : more convincing.
: In vivo tracing of the NSC fates by either transplantation or retroviral mak
: er have been done previously. But those experiments are
: hard to reveal the active regulatory role of astrocytes, because of the hete
: rogenous nature of cell composition in neurogenic region of
: DG. The massive astrocytic background in culture might, I guess, conveys som
: e information of lack of functional neurons, thus
: instructs NSC (probably SOME astrocytes themselves) to become neurons.
--
※ 来源:．The unknown SPACE bbs.mit.edu．[FROM: 128.118.]
发信人: macromind (星雨), 信区: Biology
标 题: Re: MCBJC(Neurogenesis/adult neural stem cell)
发信站: The unknown SPACE (Wed Apr 9 19:48:02 2003), 站内信件
screen for pharmacologic molecues seem unrealistic here? I'm not familiar with
this approach at all. maybe you can teach me some commonsenses.hehe
actually microarray has fished several molecules and they are gonna to publish
one of them. I have less interests in identifying any more molecules like CCg.
and you may notice in the fraction of CM, only one salient bind exists...
btw, are you interested in doing a postdoc in Gage lab? huge lab
【 在 Marble (小石头哥哥) 的大作中提到: 】
: 【 在 macromind (星雨) 的大作中提到: 】
: : To study NSC differentiation, GFP and differentiation maker can be used in
: : vitro, which is relatively easy. In vivo differentiation
: : studies usually adopt 2 strategies: transplantation or retroviral injection
: : to trace the progenies of NSC. People have done that,
: : showing that different cell types are generated, but it's really hard to say
: : these different progenies are from the same SINGLE
: : ancestor. Till now, I think there is still NO convicing evidence to demostra
: : te NSC existence in vivo. Some people even think only
: : progenitors exist over there, and astrocytes are the bona fide stem cells.
: : You made a very good point arguing that those markers are not necessarily id
: : entities of specific cell types. Actually as many labs
: : show, MAPab can also react with astrocytes and/or oligodendrocytes. But in t
: : his experiment, MAPab+ cells are certainly not
: : GFAP+ or RIP+, suggesting that MAPab+ are mostly, although not exclusively,
: : neurons.
: : Biochemically, we can purify the factors from the conditioned medium and to
: : assay their activity to regulate neurogenesis. Actually
: : the same lab identified CCg which is required for NSC proliferation and neur
: very good points. while you have listed so many answers that
: others could not participate, i have to ban you. hehe.
: as for the functional analysis, i think a long-term in vivo
: observation is important if the final goal is for clinics.
: however, when i talked with Fred Gage, he did not seem to be
: interested; one reason i think is that stem cell research is
: not welcomed by the politicians and its clinical prospect is
: still shaddowed. btw, there are too many unknowns, and it is
: still not applicable for such bold exploration. to find the
: molecules that are essential to astrocyte promoted neurogenesis,
: i have also thought about analysis of the difference b/w
: spinal chord and hippocampus. besides microarray (for total
: RNA and polysomal RNA that is termed to being translated ),
: i would like to screen for pharmcological molecules that
: interrupt with this process (too risky). biochemical analysis
: of the diffusible factors is quite important, as you have
: mentioned. it may be interesting to fractionate such peptides
: or hormones and test the effects on NSC, and determine the
: dosage response. meanwhile, i would consider investigation
: of genetically modified neural stem cell and astrocytes,
: particularly if the expression of certain key genes could
: be controlled during this process.
: : ogenesis. Obviously there are many other factors remain
: : unidentified. Microarray to compare SC- and Hippacampal astrocyte may get a
: : lot of information. I don't know and have interests in
: : listening your genetical approches.
: : In vivo tracing of the NSC fates by either transplantation or retroviral mak
: : er have been done previously. But those experiments are
: : hard to reveal the active regulatory role of astrocytes, because of the hete
: : rogenous nature of cell composition in neurogenic region of
: : DG. The massive astrocytic background in culture might, I guess, conveys som
: : e information of lack of functional neurons, thus
: : instructs NSC (probably SOME astrocytes themselves) to become neurons.
--
※ 来源:．The unknown SPACE bbs.mit.edu．[FROM: 162.129.]
发信人: assasin (冷血---何时能被加热？), 信区: Biology
标 题: Re: MCBJC(Neurogenesis/adult neural stem cell)
发信站: The unknown SPACE (Thu Apr 10 22:01:58 2003) WWW-POST
【 在 macromind (星雨) 的大作中提到: 】
: 【 在 Marble (小石头哥哥) 的大作中提到: 】
: : this Nature paper (2002 417:39) addressed the mechanisms that
: : control fate of neural stem cells. astrocytes have been
: : thought merely as supportive cells in the central nervous
: : system, however, this work has demonstrated that astrocytes
: : isolated from adult hippocampus, but not spinal chord,
: : promoted neurogenesis (i.e., neuron fate) of the adult neural
: : stem cells in cell culture. this study has highlighted the
: : effects of the environment on the specification of stem cells.
: : for stem cell research, many labs try to identify the key
: : features for cells that have "stemness", and how they could
: : be induced to differentiate into different lineages, and
: : whether different lineages could "transdifferentiate". it is
: : rather new area with many things unknown, and even experiments
: : that had doubt on previously published data could get onto
: : top journals.
: : my questions for this paper:
: : 1. what are the methodology they used to study differentiation
: : of neural stem cells? do you think there might be flaw for such
: : study (for example, primarily in vitro cell culture; counting
: : cells with differentiation marker really means that the cells
: : have differentiated into functional states)?
: To study NSC differentiation, GFP and differentiation maker can be used in
: vitro, which is relatively easy. In vivo differentiation
: studies usually adopt 2 strategies: transplantation or retroviral injection
: to trace the progenies of NSC. People have done that,
: showing that different cell types are generated, but it's really hard to say
: these different progenies are from the same SINGLE
: ancestor. Till now, I think there is still NO convicing evidence to demostra
: te NSC existence in vivo. Some people even think only
: progenitors exist over there, and astrocytes are the bona fide stem cells.
: You made a very good point arguing that those markers are not necessarily id
: entities of specific cell types. Actually as many labs
: show, MAPab can also react with astrocytes and/or oligodendrocytes. But in t
: his experiment, MAPab+ cells are certainly not
: GFAP+ or RIP+, suggesting that MAPab+ are mostly, although not exclusively,
: neurons.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
I am wondering, is there a way to label dividing NSC or such a cell in adult
hippocampus with GFP and follow its division and differentiation pattern in
isolated slice?
: : 2. they proposed that cell-attached and diffusible factors from
: : astrocytes are essential to the neurogenesis of adult stem
: : cells. how would you like to identify and characterize such
: : factors biochemically and genetically?
: Biochemically, we can purify the factors from the conditioned medium and to
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
is it easy to get enough, pure protein factor from the conditioned medium?
: assay their activity to regulate neurogenesis. Actually
: the same lab identified CCg which is required for NSC proliferation and neur
: ogenesis. Obviously there are many other factors remain
: unidentified. Microarray to compare SC- and Hippacampal astrocyte may get a
: lot of information. I don't know and have interests in
: listening your genetical approches.
: : 3. btw, Dr. Song also had a publication on Nat Neuro 2002
: : 5:438 in which he demonstrated that these stem cells had
--
※ 来源:．The unknown SPACE bbs.mit.edu．[FROM: 136.152.]
发信人: macromind (星雨), 信区: Biology
标 题: Re: MCBJC(Neurogenesis/adult neural stem cell)
发信站: The unknown SPACE (Tue Apr 15 17:59:43 2003), 转信
【 在 assasin (冷血---何时能被加热？) 的大作中提到: 】
: 【 在 macromind (星雨) 的大作中提到: 】
: : To study NSC differentiation, GFP and differentiation maker can be used in
: : vitro, which is relatively easy. In vivo differentiation
: : studies usually adopt 2 strategies: transplantation or retroviral injection
: : to trace the progenies of NSC. People have done that,
: : showing that different cell types are generated, but it's really hard to say
: : these different progenies are from the same SINGLE
: : ancestor. Till now, I think there is still NO convicing evidence to demostra
: : te NSC existence in vivo. Some people even think only
: : progenitors exist over there, and astrocytes are the bona fide stem cells.
: : You made a very good point arguing that those markers are not necessarily id
: : entities of specific cell types. Actually as many labs
: : show, MAPab can also react with astrocytes and/or oligodendrocytes. But in t
: : his experiment, MAPab+ cells are certainly not
: : GFAP+ or RIP+, suggesting that MAPab+ are mostly, although not exclusively,
: : neurons.
: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
: I am wondering, is there a way to label dividing NSC or such a cell in adult
: hippocampus with GFP and follow its division and differentiation pattern in
: isolated slice?
Time-lapse recording may be the ultimate solution.hehe
: : Biochemically, we can purify the factors from the conditioned medium and to
: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
: is it easy to get enough, pure protein factor from the conditioned medium?
It's easy to get enough conditioned medium.
: : assay their activity to regulate neurogenesis. Actually
: : the same lab identified CCg which is required for NSC proliferation and neur
: : ogenesis. Obviously there are many other factors remain
: : unidentified. Microarray to compare SC- and Hippacampal astrocyte may get a
: : lot of information. I don't know and have interests in
: : listening your genetical approches.
--
※ 来源:．The unknown SPACE bbs.mit.edu．[FROM: 162.129.]
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