Focal calcium channel modulation

Abstract

Disclosed is an invention for focally modulating the activity of a calcium channel in a mammal. In one aspect, the invention features a method that includes contacting a pre-determined tissue or organ region with a nucleic acid sequence encoding a GEM protein or a variant thereof to express the GEM protein or variant within the region. Typical methods further include expressing the GEM protein or variant so as to modulate the activity of the calcium channel. The invention has a wide spectrum of useful applications including treating a medical condition associated with unsuitable calcium channel activity.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]The present application claims priority to U.S. application Ser. No. 10 / 678,723 filed Oct. 2, 2003 U.S. Provisional Application No. 60 / 415,649 as filed on Oct. 2, 2002 the disclosure of which is incorporated herein by reference.STATEMENT OF U.S. GOVERNMENT INTEREST[0002]Funding for the present invention was provided in part by the Government of the United States by virtue of Grant Nos. R37 HL36957 and P50 HL52307 from the National Institutes of Health. Accordingly, the Government of the United States has certain rights in and to the invention claimed herein.FIELD OF THE INVENTION[0003]Calcium channels include electrically responsive proteins with many important biological functions. The present invention provides a composition, method and system for modulating calcium channels in a focal (rather than non-specific) manner. The invention has a wide spectrum of useful applications including treating a medical condition associated with undesir...

AI Technical Summary

Benefits of technology

[0022]The invention generally features a composition, method and system for modulating a calcium channel within a pre-determined region of interest. More particularly, the invention provides for focal delivery of a therapeutic protein that modulates the channel essentially at least near and preferably within the region. Preferred practice of the invention reduces or eliminates potential for unwanted modulation of calcium channel activity outside the region. Importantly, use of the invention does not rely on potentially harmful calcium channel blockers to modulate calcium channels focally.

[0024]We have also learned that cells have evolved a natural strategy for controlling calcium channel activity that employs a mammalian guanosine triphosphatase (GTPase) called Gem. It is an object of the present invention to administer the Gem protein (or a variant thereof) focally ie., to a pre-determined tissue or organ region so as to provide for specific and targeted modulation of calcium channel activity within the region. Without wishing to be bound to theory, we believe that focal delivery of the Gem protein by the invention can focally modulate calcium channel activity without significantly impacting calcium channel activity outside that region. Such targeted and specific delivery of the Gem protein (or variant) will reduce or in most cases eliminate need to employ potentially harmful calcium channel blockers. Accordingly, patient health and prognoses are expected to improve with use of the invention.

[0028]Practice of the foregoing method provides what is sometimes referred to herein as “genetic calcium channel blocker” activity. The phrase is intended to mean that the method harnesses the natural activity of the Gem protein in way that is genetically controllable by the user. Such activity is flexible and readily adapted to suit a particular therapeutic application. For instance, the method is generally intended to transfer genetic calcium blocker activity focally, that is, largely to the tissue or organ region in need of therapy. In most cases, significant modulation of channel proteins outside that region is substantially reduced and oftentimes avoided entirely. Importantly, focal transfer of the genetic calcium channel blocker of the invention substantially reduces or eliminates systemic sequelae that has overshadowed prior use of nearly all conventional calcium channel blockers. The invention thus provides caregivers with a rational approach for focally delivering a genetically controllable and naturally-occurring calcium channel blocker precisely where it is needed.

[0030]Thus in one embodiment, the invention provides a method for increasing or decreasing the activity of an L-type calcium channel in which the nucleic acid encoding the Gem protein or variant is contacted with the region along with at least one of a hydrophilic polymer and cationic liposome formulation. Preferably, such contact is under conditions sufficient to express the Gem protein or variant within the region; and expressing the GEM protein or variant encoded by the nucleic acid at a level sufficient to modulate the activity of the calcium channel within the region.

[0031]However in other embodiments, it will be useful to provide the nucleic acid encoding the Gem protein or variant as part of a recombinant animal virus. In these instances, use of the virus will provide significant reliability and flexibility as it can be designed to provide relatively high or low levels of the genetic calcium channel blocker activity as required to prevent or treat medical conditions of varying severity.

Problems solved by technology

We have observed that use of nearly all calcium channel blockers continues to be hindered by potentially life-threatening side-effects.

That is, we understand that the side-effects are often the unintended consequence of changing the activity of calcium channel proteins outside intended target areas.

These and other problems continue to plague use of a wide range of calcium channel blockers.

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