1. Non-Physiological Amino Acid (NPAA) Therapy in Pahenu2 Mice Relevance to PKU Therapy
Mike Gibson, Professor and Head
Section of Clinical Pharmacology
Washington State University (WSU) Spokane
College of Pharmacy, Spokane WA
Disclosures: None

2. Mammalian System L Transporters Specific for LNAAs
Rationale and Goals
To Selectively Lower Brain Phenylalanine
NPAAs targeting L and A systems (BBB and gut)
Maintain Other LNAAs at or Near Normal Levels
Adjuvant Therapy, Target Cognitive Improvements
Mammalian System L Transporters Specific for LNAAs
Transporter Expression Amino AcidsTransported
LAT Li (fetal), BM, Br, Pl, Te L-I-V-F-Y-W-M-H
LAT Je, Ile, Ki, Pl, Br, Te, Sp L-F-W-T-N-I-C-S-Y-V-Q
LAT Pa, Li (fetal, adult), SM L-I-V-F
LAT Pl, Ki, Leuc L-F-I-M
Pa is pancreas; Y=tyrosine; N=asparagine; Q=glutamine

3. Non-Physiological Amino Acids
A=Norleucine
B=2-Aminoisobutyrate
C=N-Methyl-2-aminoisobutyrate
D=2-aminonorbornane-2-carboxylic acid
Only NL previously used
in a mammalian system
Km values of LNAAs for LAT(s) may lead to NPAA concentrations that selectively lower Phe while minimally altering other LNAAs

4. Brain Amino Acid Transport Systems
~ Amino Acid Specificity
Considerable Overlap
Glutamine (Q): Numerous
Na Dependent/Independent
A ~ Smaller Amino Acids
L ~ Larger Amino Acids

5. Approach Dietary Administration-Clinical Relevance
Control Nitrogen Load with Casein
Monitor Brain LNAAs and Monoamines
Monitor Behavior/Movement in Future
Blood Chemistries (Safety)
Assess Effects on Nitrogen Load
Develop Methods to Quantify NPAAs

6. LNAA Metabolic Roles

7. Pilot Studies-Effect on Phe/Tyr
Phenylalanine
Tyrosine

8. Results for Monoamines
Serotonin
Dopamine

9. Additional LNAA Outcomes
Tryptophan
Total Branched Chain AAs

10. Effects on 1-Methyl Transfer
Methionine
SAMe

11. Conclusions Proof-of-Principle: Feasibility
Phe Reduction with NL, NB and MAIB
Other LNAA Effects: Lower Levels of NL and NB
Movement Effects of 3-5% NL Prominent
First Use of These in an Murine PKU Model
MAIB is a Selective A System Inhibitor
Can Clearly Reduce Phe, However
Not Previously Documented
More Benign Effects than 5% NL, 0.5% NB

12. Goals in Future Studies
Different Concentrations of NPAAs
Combinatorial Administration (BBB-Gut)
NPAA Characterization in High/Low Protein
Address Variability in Some LNAA Levels
Evaluate Method of Sacrifice
Characterize Behavior during NPAA Intervention

13. Acknowledgements Colleagues/Funding Alliance Support Kara Vogel
Brandi Wasek
Erland Arning
Terry Bottiglieri
R01 HD 58553
U54 DK 83916