Antiwrinkle Cream Ingredient May Reduce Parkinson's Risk

Pauline Anderson

August 22, 2013

Kinetin, a cellular repair molecule found in antiwrinkle creams, might restore enzyme activity related to a protein called PINK1, mutations to which raise the risk for an autosomal-recessive form of early-onset Parkinson's disease (PD), a new study suggests.

The molecule has already been shown to be well-tolerated in human trials (for familial dysautonomia, an unrelated rare, genetic, neurological disease) and in mice to cross the blood–brain barrier and achieve pharmacologically significant concentrations.

In biochemical and cellular experiments, scientists manipulated kinase-dependent cellular processes via a specifically targeted neosubstrate to turn on the action of PD-related mutant PINK1.

The research "marks a pharmacologic milestone as the first highly specific targeting of a member of an important class of enzymes called kinases to increase rather than to inhibit their activity," said the study's senior scientist, Kevan Shokat, PhD, a chemist at the Howard Hughes Medical Institute, University of California at San Francisco (UCSF), in a press release.

The approach may eventually lead to an effective treatment for patients who have mutant PINK1 that reduces kinase activity and causes the inherited form of PD.

Their findings were published in the August 15 issue of Cell.

Important Therapeutic Insights

"Although mutations in PINK1 are a rare cause of PD, the development of an effective disease-modifying therapy for any neurodegenerative disease would be a tremendous advance and could provide important therapeutic insights into disease-modifying strategies for other types of PD," said the study authors, led by Nicholas T. Hertz, PhD, a graduate student at the Howard Hughes Medical Institute, UCSF.

In PD, poorly performing mitochondria have been associated with the death of dopamine-producing nerve cells in the substantia nigra. Loss of these cells is a hallmark of PD disease, which is characterized by symptoms such as rigidity and tremor.

The PINK1 protein typically attaches to the membrane of damaged mitochondria inside cells, causing another protein, Parkin, to be recruited to cover the mitochondria and help keep the cell alive. In people with PINK1 mutations, though, Parkin is not recruited, leading to a greater amount of neuronal death.

In their efforts to somehow turn on this PINK1 function, researchers began investigating how PINK1 binds to ATP, another form of chemical energy used by cells. In experimenting with different ATP analogs, they found that one, kinetin triphosphate, or KTP, succeeded in cranking up PINK1 activity both in vitro and in cells. Kinetin, the KTP precursor, can also be applied to neurons to enhance PINK1 activity.

"We found that a small molecule, called KTP, speeds chemical reactions catalyzed by PINK1 better than ATP, the natural substrate," said Dr. Shokat in the release. "That kind of better-than-natural response is essentially unheard of."

The researchers also showed that kinetin boosts enzyme activity in nerve cells with normal PINK1. According to the authors, this finding may be relevant for the most common forms of PD, in which PINK1 is not mutated.

The research team is now testing this therapeutic approach in animal models of PD.

Although many drugs that inhibit the activity of kinases have been developed during the last decade, including 15 currently approved to treat cancer, none has yet been marketed to directly boost activity of a kinase.

The results of this research also raise the question of whether similar pharmaceutical strategies might be used for combatting diseases other than PD, including diabetes and cancer.

Cell. 2013;154:737-747. Abstract

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