Patent Profile: Redpoint Bio Announces Issuance of Patent for Identifying Taste Signaling Modulators

    By Donald Zuhn --

Redpoint Bio Corp. announced earlier this month that the U.S. Patent and Trademark Office has issued U.S. Patent No. 7,341,842, which is directed to methods of methods for identifying modulators of the TRP8-mediated taste response.  Such modulators can be used as flavor enhancers in foods, beverages, or pharmaceuticals to either inhibit or promote the perception of bitterness or sweetness.  While the '842 patent is assigned to the Mount Sinai School of Medicine, Redpoint Bio notes that it has exclusively licensed the patent.

According to Redpoint Bio's statement, the '842 patent covers assay technology that can be used to identify modulators of the TRPM5 (formerly TRP8) ion channel).  The TRPM5 ion channel, which is highly expressed in taste receptor cells, is associated with the perception of bitter, sweet, and savory (umami) tastes.  Redpoint Bio CEO Dr. Raymond Salemme stated that the '842 patent would significantly strengthen the Ewing, N.J-based biotech company's intellectual property position with respect to taste modulators of TRPM5.  Redpoint Bio's pharmaceutical program uses a biochemical approach aimed at suppressing the bitterness of medicines, which has the potential to expand the range of formulation options and increase patient compliance.

Figure 14 of the '842 patent shows potential signal transduction pathways in the taste receptor cells of taste buds that involve TRPM5 (TRP8).  The '842 patent explains that responses to bitter compounds are initiated by binding to one or more gustducin-coupled receptors of the T2R/TBR family, which results in the release of that molecule's beta-gamma moiety, which in turn stimulates PLC-beta2, resulting in the production of inositol triphosphate (IP) and diacylglycerol (DAG).  IP binds to its receptors and causes the release of Ca++ from intracellular stores, triggering activation of TRP8 channels, which ultimately leads to the influx of Ca++ through TRP8 channels.  DAG may act directly on TRP8 to lead to Ca++ influx.

The '842 patent issued from U.S. Application No. 11/405,097, filed April 17, 2006, which is a divisional of U.S. Application No. 09/834,792, filed April 13, 2001, which claims the benefit of U.S. Provisional Application No. 60/197,491, filed April 17, 2000.  Representative claim 1 of the '842 patent recites:

1.  A method for identifying a compound that modulates TRP8 activity, said method comprising:
    (i) contacting a cell expressing the TRP8 channel protein of SEQ ID NO: 4 with a test compound and a compound or molecular complex that results in TRP8 activation, and measuring the level ofTRP8 activation;
    (ii) in a separate experiment, contacting a cell expressing the TRP8 channel protein of SEQ ID NO: 4 with a compound or molecular complex that results in TRP8 activation and measuring the level of TRP8 activation, where the conditions are essentially the same as in part (i); and
    (iii) comparing the level of TRP8 activation measured in part (i) with the level of TRP8 activation measured in part (ii),
    wherein said measuring the level of TRP8 activation comprises measuring the membrane potential of the cell, and
    wherein a decrease in the level of TRP8 activation in the presence of the test compound indicates that the test compound is a TRP8 inhibitor, and an increase in the level of TRP8 activation in the presence of the test compound indicates that the test compound is a TRP8 activator.