New Clues To Hereditary Blinding Disease Found

Discussion in 'Optometry Archives' started by Roman Bystrianyk, Aug 24, 2004.


    "New Clues To Hereditary Blinding Disease Found", Science Daily,
    August 24, 2004,

    Seeking a cure for an inherited disease that causes blindness in over
    one million people worldwide, Dartmouth Medical School researchers
    have discovered a critical role for zinc in retinitis pigmentosa. The
    amount of zinc, a trace metal naturally absorbed by the body, can
    determine whether a key protein for vision functions normally or
    misfolds, they found.

    An inability to successfully bind zinc to rhodopsin, a light receptor
    protein in the eye, can trigger retinitis pigmentosa (RP), a
    degenerative disease that leaves many patients legally blind by the
    age of 40. The findings parallel similar progress in harnessing
    essential trace metals in the body to treat several neurodegenerative
    diseases including Alzheimer's, Parkinson's and Lou Gehrig's Disease.

    The research, appearing as the "Paper of the Week" in the August 20
    issue of the Journal of Biological Chemistry (JBC), is the first
    confirmation that zinc is present and plays a significant role in the
    normal folding and functions of rhodopsin, and if defective, leads to
    retinal degeneration.

    "We have found if there is not enough zinc in the body or there is a
    mutation in the zinc binding site, the protein rhodopsin will misfold
    and break down, triggering cell death, degeneration of the retina and
    eventually blindness," said John Hwa, MD, PhD, assistant professor of
    pharmacology and toxicology at Dartmouth Medical School. "What is
    especially exciting about this new direction in our research is that
    this characteristic of rhodopsin is very similar to other proteins
    implicated in many neurodegenerative and human diseases. The fact that
    a trace metal can have such a critical impact on rhodopsin's ability
    to function properly may point to significant advances for research in
    other devastating illnesses as well."

    The principles of the protein rhodopsin may be extended to its
    relatives: G-protein coupled receptors that mediate numerous functions
    in the body including sight, taste, smell and many important hormonal
    responses in the body.

    "Rhodopsin is a prototypical G-protein coupled receptor," said
    Aleksandar Stojanovic, a graduate student at DMS who co-authored the
    article with Hwa and Jeremiah Stitham at DMS. "The fact that it is so
    susceptible to misfolding and breakdown based on the level of zinc
    could open new frontiers of research for many diseases."

    Hwa and colleagues discovered a cluster of RP mutations localized
    within and around the area where zinc is supposed to bind with
    rhodopsin. They investigated different amounts of zinc at the
    rhodopson binding site to determine what amount leads to a successful
    binding and what causes the protein to misfold. According to Hwa, zinc
    has a strong presence in the body; the average person has 2.3 grams of
    zinc, making it the second most prevalent trace metal behind iron.

    "We are slowly figuring out the importance of everyday elements, like
    zinc, in maintaining normal function of proteins in the body," said
    Hwa. "In addition to rhodopsin, I predict that scientists will find
    that more and more proteins and receptors are impacted by trace metals
    and may open new areas in the treatment of neurodegenerative and other
    types of human diseases."
    Roman Bystrianyk, Aug 24, 2004
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.