ABSTRACT
CNS leukocytic invasion in experimental allergic encephalomyelitis (EAE) depends on alpha4beta1 integrin/vascular cell adhesion molecule-1 (VCAM-1) interactions. A small molecule inhibitor of alpha4beta1 integrin (CT301) was administered to guinea pigs in the chronic phase (>d40) of EAE for 10, 20, 30 or 40 days. CT301 elicited a rapid, significant improvement in the clinical and pathological scores that was maintained throughout the treatment period. A progressive loss of cells in the spinal cord of treated animals confirmed the resolution of inflammation associated with clinical recovery. Therefore, prolonged inhibition of alpha4beta1 integrin caused a sustained reversal of disease pathology in chronic EAE and may be similarly useful in MS.
Subject(s)
Encephalomyelitis, Autoimmune, Experimental/drug therapy , Integrin alpha4 , Animals , Chronic Disease , Cytokines/biosynthesis , Cytokines/genetics , Encephalomyelitis, Autoimmune, Experimental/diagnosis , Encephalomyelitis, Autoimmune, Experimental/pathology , Female , Flow Cytometry , Guinea Pigs , Kinetics , Polymerase Chain Reaction , RNA, Messenger/biosynthesis , Spinal Cord/pathologyABSTRACT
Converging lines of evidence implicate the beta-amyloid peptide (Ass) as causative in Alzheimer's disease. We describe a novel class of compounds that reduce A beta production by functionally inhibiting gamma-secretase, the activity responsible for the carboxy-terminal cleavage required for A beta production. These molecules are active in both 293 HEK cells and neuronal cultures, and exert their effect upon A beta production without affecting protein secretion, most notably in the secreted forms of the amyloid precursor protein (APP). Oral administration of one of these compounds, N-[N-(3,5-difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester, to mice transgenic for human APP(V717F) reduces brain levels of Ass in a dose-dependent manner within 3 h. These studies represent the first demonstration of a reduction of brain A beta in vivo. Development of such novel functional gamma-secretase inhibitors will enable a clinical examination of the A beta hypothesis that Ass peptide drives the neuropathology observed in Alzheimer's disease.
Subject(s)
Alzheimer Disease/metabolism , Amyloid beta-Peptides/metabolism , Brain/metabolism , Dipeptides/administration & dosage , Endopeptidases/metabolism , Administration, Oral , Alzheimer Disease/drug therapy , Alzheimer Disease/genetics , Amyloid Precursor Protein Secretases , Amyloid beta-Protein Precursor/genetics , Amyloid beta-Protein Precursor/metabolism , Animals , Aspartic Acid Endopeptidases , Brain/cytology , Brain/drug effects , Cells, Cultured , Disease Models, Animal , Dose-Response Relationship, Drug , Drug Evaluation, Preclinical , Endopeptidases/drug effects , Enzyme Inhibitors/administration & dosage , Female , Humans , Injections, Subcutaneous , Kidney/cytology , Kidney/drug effects , Kidney/metabolism , Male , Mice , Mice, Transgenic , Neurons/cytology , Neurons/drug effects , Neurons/metabolism , Peptide Fragments/metabolismABSTRACT
Several recent advances have provided new insights and possibilities in defining therapeutic targets for Alzheimer's disease. Of particular importance is the identification of the beta-secretase enzyme and the demonstration that immunization of a transgenic mouse model of Alzheimer's disease with Abeta(1-42) peptide can prevent or alleviate neuropathological features of the disease.
Subject(s)
Alzheimer Disease/therapy , Alzheimer Disease/enzymology , Amyloid Precursor Protein Secretases , Amyloid beta-Peptides/immunology , Amyloid beta-Protein Precursor/metabolism , Animals , Aspartic Acid Endopeptidases/metabolism , Disease Models, Animal , Endopeptidases , Humans , Immunization , Mice , Mice, Transgenic , Molecular Structure , Peptide Fragments/immunology , Plaque, Amyloid/metabolismABSTRACT
A series of inhibitors of angiotensin converting enzyme (ACE, dipeptidyl carboxypeptidase, EC 3.4.15.1) is described which addresses certain conformational aspects of the enzyme-inhibitor interaction. In this study the alanylproline portion of the potent ACE inhibitor enalaprilat (2) is replaced by a series of monocyclic lactams containing the required recognition and binding elements. In order to more fully assess the lactam ring conformations and the key backbone angle psi as defined in 3 with respect to possible enzyme-bound conformations, a series of model lactams was investigated with use of molecular mechanics. The results point to a correlation between inhibitor potency (IC50) and the computed psi angle for the lowest energy conformation of the model compounds. Thus the psi angle as defined in 3 is an important determinant in the binding of inhibitors to ACE. The inhibition data in conjunction with the computational data have served to define a window of psi angles from 130 degrees to 170 degrees which seems to be acceptable to the ACE active site.
Subject(s)
Angiotensin-Converting Enzyme Inhibitors , Enalapril/analogs & derivatives , Enalapril/pharmacology , Enalaprilat , Molecular Conformation , Structure-Activity Relationship , X-Ray DiffractionABSTRACT
A class of potent inhibitors of angiotensin-converting enzyme (dipeptidyl carboxypeptidase, E.C. 3.4.15.1) is reported, in which an alpha-aza substitution into the substituted N-carboxymethyl dipeptide structure of enalapril is made. The inhibitors 2 exhibit striking alterations in their conformational and acid-base properties due to the aza substitution, as is clear from pKa data and the x-ray crystal structure of a model azapeptide. In spite of this, they bind tightly to the enzyme, with inhibitor potency comparable to that of captopril.
Subject(s)
Angiotensin-Converting Enzyme Inhibitors , Aza Compounds/chemical synthesis , Peptides/chemical synthesis , Aza Compounds/pharmacology , Indicators and Reagents , Peptides/pharmacology , Protein Conformation , Structure-Activity RelationshipABSTRACT
A series of potent inhibitors of angiotensin-converting enzyme (dipeptidyl carboxypeptidase, E.C. 3.4.15.1) derived from benzofused 1-carboxyalkyl-3-(1-carboxy-3-phenyl-propylamino) lactams (III) is described. In the most effective inhibitors (I50 2-4 X 10(-9)M) the lactam is 7 or 8 membered and the N-1 side chain is carboxymethyl or carboxyethyl. Conformational and steric factors pertinent to binding to the enzyme are discussed.
Subject(s)
Angiotensin-Converting Enzyme Inhibitors , Lactams/chemical synthesis , Indicators and Reagents , Lactams/pharmacology , Molecular Conformation , Structure-Activity RelationshipABSTRACT
Several phosphonamides, phosphoramides, and phosphates having the general structure R-Y-P(O)(OH)-X-CH(CH3)-CO-Pro have been synthesized and tested for inhibition of angiotensin-converting enzyme (dipeptidyl carboxypeptidase; peptidyl-dipeptide hydrolase, EC 3.4.15.1). Inhibition was found to depend on the nature of R, Y, and X such that the maximal effect was observed when X = NH, Y = CH2, and R = phi CH2 (50% inhibition at 7 nM). Substitution of CH2 or O at X and O at Y produced significantly less potent inhibitors. Groups shorter or longer than R = phi CH2 led to less active inhibitors, presumably due to nonoptimal interaction of the side chain with the S1 subsite.
Subject(s)
Angiotensin-Converting Enzyme Inhibitors , Glycopeptides/pharmacology , Organophosphorus Compounds/pharmacology , Enzyme Inhibitors , Phosphates/pharmacology , Structure-Activity Relationship , Substrate SpecificityABSTRACT
Much current attention focuses on the renin-angiotensin system in relation to mechanisms controlling blood pressure and renal function. Recent demonstrations (ref. 1, ref. 2 and refs therein) that angiotensin-converting enzyme inhibitors show promising clinical antihypertensive properties have been of particular interest. We now report on the design of a novel series of substituted N-carboxymethyl-dipeptides which are active in inhibiting angiotensin-converting enzyme at nanomolar levels. We suggest that these compounds are transition-state inhibitors and that extensions of this design to other metalloendopeptidases merit further study.
