Hi, Ken,
9/02/00 0:06
Somewhere amongst all this Ken raised the idea of searching for something
specific about the death of motoneurons. While not specifically addressing
his question, the paper below touches on this matter in another way
The Journal of Neuroscience, January 1, 1998, 18(1):104-111
Motoneuron Apoptosis Is Blocked by CEP-1347 (KT 7515), a Novel
Inhibitor of the JNK Signaling Pathway
Anna C. Maroney,1 Marcie A. Glicksman,1 Alie N. Basma,1 Kevin M. Walton,1
Ernest Knight Jr,1
Carol A. Murphy,1 Becky A. Bartlett,1 James P. Finn,1 Thelma Angeles,1
Yuzuru Matsuda,2 Nicola T. Neff,1 and
Craig A. Dionne 1
Abstract:
"Neurons undergoing apoptosis can be rescued by trophic fac-tors that
simultaneously increase the activity of extracellular signal-regulated
kinase (ERK) and decrease c-Jun N-terminal kinase (JNK) and p38. We
identified a molecule, CEP-1347 (KT7515), that rescues motoneurons
undergoing apoptosis and investigated its effect on ERK1 and JNK1 activity.
Cultured rat embryonic motoneurons, in the absence of trophic factor, be-gan
to die 24-48 hr after plating. During the first 24 hr ERK1 activity was
unchanged, whereas JNK1 activity increased four-fold. CEP-1347 completely
rescued motoneurons for at least 72 hr with an EC50 of 20 6 2 nM. CEP-1347
did not alter ERK1 activity but rapidly inhibited JNK1 activation. The IC50
of CEP-1347 for JNK1 activation was the same as the EC50 for mo-toneuron
survival. Inhibition of JNK1 activation by CEP-1347 was not selective to
motoneurons. CEP-1347 also inhibited JNK1 activity in Cos7 cells under
conditions of ultraviolet irra-diation, osmotic shock, and inhibition of
glycosylation. Inhibi-tion by CEP-1347 of the JNK1 signaling pathway
appeared to be selective, because CEP-1347 did not inhibit p38-regulated
mitogen-activated protein kinase-activated protein kinase-2 (MAPKAP2)
activity in Cos7 cells subjected to osmotic shock. The direct molecular
target of CEP-1347 was not JNK1, be-cause CEP-1347 did not inhibit JNK1
activity in Cos7 cells cotransfected with MEKK1 and JNK1 cDNA constructs.
This is the first demonstration of a small organic molecule that pro-motes
motoneuron survival and that simultaneously inhibits the JNK1 signaling
cascade. Key words: motoneurons; indolocarbazole; CEP-1347; sur-vival;
apoptosis; c-Jun N-terminal kinase; mitogen-activated protein kinase; p38"
Quick extracts
"In an effort to identify small molecules that promote neuronal survival, we
selected CEP-1347, also known as KT7515, for its ability to induce choline
acetyl transferase (ChAT) activity in cultures prepared from embryonic
spinal cord and basal forebrain tissue (Kaneko et al., 1997)."
------
"The morphology of motoneuron cultures was assessed in the presence of
CEP-1347. In contrast to control cultures that rapidly underwent neurite
retraction and cellular fragmentation, those cells treated with CEP-1347
displayed a flattened cell body mor-phology with extensive neuritic
processes for at least 5 d (Fig. 3a,b). To determine whether cells in
control cultures were dying by apoptosis, we examined chromatin condensation
by staining the DNA with fluorescent Hoechst dye. By 48 hr a significant
proportion of untreated motoneurons exhibited clear hallmarks of chromatin
condensation, consistent with a previous report that cultures of enriched
motoneurons in the absence of neurotrophic factors die in an apoptotic
manner (Fig. 3c) (Comella et al., 1994; Milligan et al., 1994). In contrast,
CEP-1347-treated cultures exhibited diff use nuclear staining, consistent
with the survival activity detected by the calcein assay (Fig. 3d)."
Acetylcholine promoting survival??? This protective effect is selective, but
neurons other than motoneurons are involved. Good guess John.
Now Ken, do you know if the ocular motoneurons are always saved or just take
longer to die?
Thanks,
John.
kenneth Collins <kpaulc at earthlink.net> wrote in message
news:3897A68B.46C96485 at earthlink.net...
> hi, John.
>> John H. wrote:
> >
> > Thanks Dag and Austin,
> >
> > I remembered the article so will cite it here (good read for me):
> >
> > "Sealing one's fate: control of cell death in neurons"
> > Louise Bergeron and Junying Yuan
> >
> > Current Opinion in Neurobiology 1998, 8:55-63
> >
> > p 60
> > In humans, ALS is characterized by the progressive loss of motor neurons
int
> > he brain stem and spinal cord [ain't that great news Ken],
>> yes, thanks for posting this stuff.
>> >leading to muscle
> > weakness and atrophy followed by paralysis and death. While most cases
are
> > sporadic, 5-10% are familial (FALS). A breakthrough came ... SOD1. ...
> > Kostic et al crossed transgenic mice overexpressing BCL-2 neurons with
mice
> > carrying the FALS SOD1 mutation. BCL-2 was effective at delaying the
onset
> > of the disease, thus increasing lifespan of themice by about 19%;
however,
> > once symptoms appeared, progression to paralysis and death remained
> > unchanged. BCL-2 delayed both the loss of motor neurons and theincrease
in
> > expression oftyhe early markers of cell injury, c-Jun and ubiquitin. ...
"
>> from the perspect of the hypothesis i've been discussing, i expect that
> what the adminstered agents are doing is augmenting the neurons'
> abilities to cope with 'excito-toxic' conditions that're generated by
> the decrease of type II synchronization.
>> what's actually needed is a tracking-doen of the 'lesion' through which
> the interminable TD E/I(up) condition is being interjected into the
> supersystem, and fixing things at the 'lesion' site.
>> of course, if, contrry to the hypothesis i've been discussing, the
> 'lesion' is, in fact, a genetic 'lesion' that's distributed theougout
> the supersystem, then it seems that the only way to possibly attack the
> 'lesion' would be through globally-distributed chemo approach, with
> respect to which, i'm out of my depth.
>> it's just that it doesn't seem to be globally-distributed because
> sensory fx is unaffected. and, on the motor side, things are obviously
> 'chained', with both feedback and feed-forward dynamics, so the
> possibility of finding a low-'level', relatively-'discrete' TD E/I(up)
> interjecting site, at which dysfunction can be 'fixed', is real.
>> k. p. collins
>> >
> > BCL-2 can useful in delaying apoptosis in other pathologies also. A
paper I
> > read recently suggested that the p53 gene may regulate apoptosis via the
> > BCL-2\BAX etc ratios. So I'm not sure how significant this BCL-2 delay
is,
> > except for the possibility that mitachondrial membrane permeability or
> > dysfunction is probably involved. Once cytochrome c and AIF are away in
the
> > cytoplasm and the caspase cascade is away I think cell death is
inevitable.
> > (?)
> >
> > Perhaps BCL-2, at least in motor neurons, is particularly sensitive to
some
> > type of oxidative stress.
> > I need to brush up, find out if oxidative stress alone can activate
> > procapase 9. Haven't even looked at motor neurons though.
> >
> > Little by little,
> >
> > John H.
> >
> > Austin P. So (Hae-Jin) <haejin at netinfo.ubc.caX> wrote in message
> > news:3895CA2F.2A802315 at netinfo.ubc.caX...> > > Familial ALS has been linked to SOD mutations....but that accounts for
<
> > 5% of
> > > all ALS cases, so in fact the field is still very wide open.
> > >
> > > So...mitochondrial dysfunction is a good candidate, as is an
autoimmune
> > response
> > > (Llinas touted this for a while before the FALS/SOD link was
> > found...antibodies
> > > against the P-type channel). People have speculated on a glutamate
> > excitotoxic
> > > source....but again nothing concrete.
> > >
> > >
> > > "John H." wrote:
> > >
> > > > I thought it may have been a SOD problem, but haven't managed to
have a
> > > > close look at it yet. Isn't there a familial tendency here also?
> > > >
> > > > Would someone more knowledgeable than the current authors in this
thread
> > > > care to enlighten? I know something about apoptosis etc but ALS ....
.
> > >
> > > --
> > > ---
> > > Austin P. So (Hae Jin)
> > >
> > > I.I.S.G.P.
> > > Biotechnology Laboratory
> > > University of British Columbia
> > >
> > > E-mail: haejin at netinfo.ubc.ca> > >
> > > http://www.interchange.ubc.ca/haejin/index.html (under construction)
> > >
> > >
