ascorbic acid and fibroblasts
Bryan L. Ford
fordb at bcc.orst.edu
Mon Mar 3 01:34:06 EST 1997
Leonid A. Sadofiev wrote:
> In his letter Dr. Bijur wrote:
> >Is there anybody out there who knows if ascorbic acid (vitamin C) causes
> >differentiation of fibroblasts. It has been established that ascobate does
> >induce the synthesis of collagen.
> >Gautam Bijur
> Dear Gautam,
> Sorry, but something is wrong. Ascorbic acid does't induce the collagen synthesis.
> During collagen formation there are some posttranslational
> modification occures. One of them is hydroxylation of some proline
> residies in the chain giving 4- or 3-hydroxyproline.
> Such a process is absolutely neccessary for collagen formation.
> This hydroxylation is an enzymatic process and requers the presence
> of ascorbic acid. Without vitamin C this reaction does't occur.
> So, ascorbic acid does't affect collagen genes transcription, but
> only give the ability to build normal, mature collagen.
Leonid A. Sadofiev
Something may be wrong, but it appears not to be the assertion (and
question) of Gautam Bijur. Please see: S. Kurata, H. Senoo and R. Hata
in Exp. Cell Res. 206, 63-71 (1993) "Transcriptional activation of type
I collagen genes by ascorbic acid-2-phosphate in human skin fibroblasts
and its failure in cells from a patient with alpha 2(I)-chain-defective
Ehlers-Danlos Syndrome". The article also ascribes similar activity to
Such a relationship should not be too surprising considering the
necessities of integrating complex biochemical and cellular events. One
frequently finds that a rate-limiting cofactor, metablic intermediate or
substrate in a biosynthetic pathway will itself strongly regulate one or
more of the critical genes of that same biosynthetic pathway. Very
"handy" from teleological standpoint, I would think. Since ascorbate is
also involved in type II collagen maturation one should not be surprised
to see that it also regulated transcription of these genes as well.
I regret that I can't shed much if any light on the original issue of
fibroblast differentiation, but I would say the question is still at
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