Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019693 (HIV)
 170,526 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Leukocytes accumulate at sites of inflammation and microbial infection in direct response to locally produced chemotactic factors, which signal through specific G protein-coupled receptors. The first chemotactic factors to be structurally defined were the N-formyl peptides. Unlike other leukocyte chemoattractants, N-formyl peptides could originate from either an endogenous source, such as the mitochondrial proteins of ruptured host cells, or an exogenous source, such as the proteins of invading pathogens. This suggests that the formyl-peptide receptor (FPR) and its variant FPRL1 (FPR-like 1) are involved in host defense against bacterial infection and in the clearance of damaged cells. Recently, additional, more complex, roles for these receptors have been proposed because FPR, and to a greater extent FPRL1, have been found to interact with a menagerie of structurally diverse pro- and anti-inflammatory ligands associated with different diseases, including amyloidosis, Alzheimer's disease, prion disease and HIV. How these receptors recognize such diverse ligands, which are the most important in vivo, and how they contribute to disease pathogenesis and host defense are basic questions currently under investigation that could lead to new therapeutic targets.
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PMID:Formyl-peptide receptors revisited. 1240 7

Glutamate transport is central to neurotransmitter functions in the brain. Impaired glutamate transport induces neurotoxicity associated with numerous pathological processes, including stroke/ischemia, temporal lobe epilepsy, Alzheimer's disease, amyotrophic lateral sclerosis, Huntington's disease, HIV-1-associated dementia, and growth of malignant gliomas. Excitatory amino acid transporter-2 (EAAT2) is a major glutamate transporter in the brain expressed primarily in astrocytes. We presently describe the cloning and characterization of the human EAAT2 promoter, demonstrating elevated expression in astrocytes. Regulators of EAAT2 transport, both positive and negative, alter EAAT2 transcription, promoter activity, mRNA, and protein. These findings imply that transcriptional processes can regulate EAAT2 expression. Moreover, they raise the intriguing possibility that the EAAT2 promoter may be useful for targeting gene expression in the brain and for identifying molecules capable of modulating glutamate transport that could potentially inhibit, ameliorate, or prevent various neurodegenerative diseases.
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PMID:Insights into glutamate transport regulation in human astrocytes: cloning of the promoter for excitatory amino acid transporter 2 (EAAT2). 1257 75

The last decade has witnessed an effervescence of research interest in the development of potent inhibitors of various aspartic peptidases. As an enzyme family, aspartic peptidases are relatively a small group that has received enormous interest because of their significant roles in human diseases like involvement of renin in hypertension, cathepsin D in metastasis of breast cancer, beta-Secretase in Alzheimer's Disease, plasmepsins in malaria, HIV-1 peptidase in acquired immune deficiency syndrome, and secreted aspartic peptidases in candidal infections. There have been developments on clinically active inhibitors of HIV-1 peptidase, which have been licensed for the treatment of AIDS. The inhibitors of plasmepsins and renin are considered a viable therapeutic strategy for the treatment of malaria and hypertension. Relatively few inhibitors of cathepsin D have been reported, partly because of its uncertain role as a viable target for therapeutic intervention. The beta-secretase inhibitors OM99-2 and OM003 were designed based on the substrate specificity information. The present article is a comprehensive state-of-the-art review describing the aspartic peptidase inhibitors illustrating the recent developments in the area. In addition, the homologies between the reported inhibitor sequences have been analyzed. The understanding of the structure-function relationships of aspartic peptidases and inhibitors will have a direct impact on the design of new inhibitor drugs.
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PMID:Aspartic peptidase inhibitors: implications in drug development. 1274 95

The characterization of the enzymes responsible for amyloid beta-peptide (Abeta) production is considered to be a primary goal towards the development of future therapeutics for the treatment of Alzheimer's disease. Inhibitors of gamma-secretase activity were critical in demonstrating that the presenilins (PSs) likely comprised at least part of the active site of the gamma-secretase enzyme complex, with two highly conserved membrane aspartates presumably acting as catalytic residues. However, whether or not these aspartates are actually the catalytic residues of the enzyme complex or are merely essential for normal PS function and/or maturation is still unknown. In this paper, we report the development of reactive inhibitors of gamma-secretase activity that are functionally irreversible. Since such inhibitors have been shown to bind catalytic residues in other aspartyl proteases (e.g., HIV protease), they might be used to determine if the transmembrane aspartates of PSs are involved directly in substrate cleavage.
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PMID:Peptide-based, irreversible inhibitors of gamma-secretase activity. 1276 25

Carnitine is an ammo acid derivative found in high energy demanding tissues (skeletal muscles, myocardium, the liver and the suprarenal glands). It is essential for the intermediary metabolism of fatty acids. Carnitine is indispensable for beta-oxidation of long-chain fatty acids in the mitochondria but also regulates CoA concentration and removal of the produced acyl groups. AcylCoAs act as restraining factor for several enzymes participating in intermediary metabolism. Transformation of AcylCoA into acylcarnitine is an important system for removing the toxic acyl groups. Although primary deficiency is unusual, depletion due to secondary causes, such as a disease or a medication side effect, can occur. Primary carnitine deficiency is caused by a defect in plasma membrane carnitine transporter in muscle and kidneys. Secondary carnitine deficiency is associated with several inborn errors of metabolism and acquired medical or iatrogenic conditions, for example in patients under valproate and zidovuline treatment. In cirrhosis and chronic renal failure, carnitine biosynthesis is impaired or carnitine is lost during hemodialysis. Other chronic conditions like diabetes mellitus, heart failure, Alzheimer disease may cause carnitine deficiency also observed in conditions with increased catabolism as in critical illness. Preterm neonates develop carnitine deficiency due to impaired proximal renal tubule carnitine re-absorption and immature carnitine biosynthesis. Carnitine stabilizes the cellular membrane and raises red blood cell osmotic resistance but has no metabolic influence on lipids in dialysis patients. L-Carnitine has been administered in senile dementia, metabolic nerve diseases, in HIV infection, tuberculosis, myopathies, cardiomyopathies, renal failure anemia and included in baby foods and milk.
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PMID:Carnitine metabolism and deficit--when supplementation is necessary? 1276 64

A series of new 7-substituted-4-chloro-3-alkoxy isocoumarin derivatives were synthesized and evaluated as inhibitors of representative classes of proteases: serine protease (alpha-chymotrypsin, trypsin), cysteine protease (Caspase-3), and aspartyl protease (HIV-protease), 20S proteasome and also as inhibitors of amyloid peptide gamma-secretase-mediated production. Protease inhibition selectivity is directly related to the structure of the substituent at the 7-position of the isocoumarin nucleus. 7-Nitro-isocoumarin derivatives (4c, 4d, 4f) are potent alpha-chymotrypsin inhibitors but slightly active or inactive on HIV-protease, as well as on cysteine protease. In contrast, only derivatives bearing a free amino (5d, 5f) or a substituted amino group (6f) at the 7-position of the isocoumarin nucleus, were found weakly active or inactive on alpha-chymotrypsin, trypsin, Caspase-3 and HIV-protease, but prevent gamma-secretase-mediated production of Abeta 40/42 amyloid peptides, which is known to be involved in Alzheimer's disease. Moreover, the most active compounds on beta-amyloid peptide production [JLK6 (5d), JLK2 (5f) and JLK7 (6f)] show only weak or moderate inhibitory activity on the 20S proteasome. The obtained results suggest that the described new isocoumarin analogues could be of interest, since compounds like JLK6 (5d), JLK2 (5f) and JLK7 (6f) can be considered as possible hits for the development of new agents directed towards Alzheimer's disease.
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PMID:Synthesis of new 3-alkoxy-7-amino-4-chloro-isocoumarin derivatives as new beta-amyloid peptide production inhibitors and their activities on various classes of protease. 1281 77

Recent in vitro studies suggest that the alpha chemokine stromal-derived factor-1alpha (SDF-1alpha) and its receptor CXCR-4 may contribute to neuronal apoptosis in HIV infection of the brain. The cellular and regional expression of this chemokine and its relationship to the AIDS dementia complex (ADC), however, have remained undetermined. Using immunohistochemistry and semiquantitative RT-PCR, we examined the expression of SDF-1alpha in the frontal cortex (FC), the adjacent deep white matter (DWM). and the basal ganglia (BG) of 17 patients with ADC and 5 normal controls, and the FC and temporal cortex of 6 patients with Alzheimer disease (AD). Additionally, SDF-1alpha expression was studied in 3 different neuronal cultures: differentiated SK-N-MC cells, primary human fetal neuronal, and mouse hippocampal cultures. SDF-1alpha staining was predominantly localized to astrocytes in all 3 groups in the gray matter of the FC and the BG, often in the vicinity of cortical and basal ganglia neurons, but was generally absent in the DWM. Further, the number of positive neurons was significantly greater in the BG of AIDS subjects with advanced brain disease compared to subjects with lesser disease (p = 0.029). All cultures showed prominent SDF-1alpha staining of neurons within the cytoplasm and in neurites, whereas preferential expression in GABA-ergic neurons was found in hippocampal cultures. This is the first study to show that SDF-1alpha is constitutively expressed in astrocytes of the deep and cortical gray matter as well as in neurons of the human brain. Its increased expression in basal ganglia neurons of patients with advanced HIV CNS disease suggests it may also contribute to pathogenesis.
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PMID:SDF-1alpha is expressed in astrocytes and neurons in the AIDS dementia complex: an in vivo and in vitro study. 1283 6

Biocatalytic processes were used to prepare chiral intermediates for pharmaceuticals. These include the following processes. Enzymatic synthesis of [4S-(4a,7a,10ab)]1-octahydro-5-oxo-4-[[(phenylmethoxy) carbonyl]amino]-7H-pyrido-[2,1-b] [1,3]thiazepine-7-carboxylic acid methyl ester (BMS-199541-01), a key chiral intermediate for synthesis of a new vasopeptidase inhibitor. Enzymatic oxidation of the epsilon-amino group of lysine in dipeptide dimer N2-[N[[(phenylmethoxy)carbonyl] L-homocysteinyl] L-lysine)1,1-disulfide (BMS-201391-01) to produce BMS-199541-01 using a novel L-lysine epsilon-aminotransferase from S. paucimobilis SC16113 was demonstrated. This enzyme was overexpressed in E. coli, and a process was developed using recombinant enzyme. The aminotransferase reaction required alpha-ketoglutarate as the amine acceptor. Glutamate formed during this reaction was recycled back to alpha-ketoglutarate by glutamate oxidase from S. noursei SC6007. Synthesis and enzymatic conversion of 2-keto-6-hydroxyhexanoic acid 5 to L-6-hydroxy norleucine 4 was demonstrated by reductive amination using beef liver glutamate dehydrogenase. To avoid the lengthy chemical synthesis of ketoacid 5, a second route was developed to prepare the ketoacid by treatment of racemic 6-hydroxy norleucine (readily available from hydrolysis of 5-(4-hydroxybutyl) hydantoin, 6) with D-amino acid oxidase from porcine kidney or T. variabilis followed by reductive amination to convert the mixture to L-6-hydroxynorleucine in 98% yield and 99% enantiomeric excess. Enzymatic synthesis of (S)-2-amino-5-(1,3-dioxolan-2-yl)-pentanoic acid (allysine ethylene acetal, 7), one of three building blocks used for synthesis of a vasopeptidase inhibitor, was demonstrated using phenylalanine dehydrogenase from T. intermedius. The reaction requires ammonia and NADH. NAD produced during the reaction was recycled to NADH by oxidation of formate to CO2 using formate dehydrogenase. Efficient synthesis of chiral intermediates required for total chemical synthesis of a beta 3 receptor agonist was demonstrated. These include: (a) microbial reduction of 4-benzyloxy-3-methanesulfonylamino-2'-bromoacetophenone 9 to corresponding (R)-alcohol 10 by S. paucimobilis SC16113, (b) enzymatic resolution of racemic alpha-methyl phenylalanine amide 11 and alpha-methyl-4-hydroxyphenylalanine amide 13 by amidase from M. neoaurum ATCC 25795 to prepare corresponding (S)-amino acids 12 and 14, and (c) asymmetric hydrolysis of methyl-(4-methoxyphenyl)-propanedioic acid ethyl diester 15 to corresponding (S)-monoester 16 by pig liver esterase. (S)[1-(acetoxyl)-4-(3-phenyl)butyl]phosphonic acid diethyl ester 21, a key chiral intermediate required for total chemical synthesis of BMS-188494 (an anticholesterol drug) was prepared by stereoselective acetylation of racemic [1-(hydroxy)-4-(3-phenyl)butyl]phosphonic acid diethyl ester 22 using G. candidum lipase. Lipase-catalyzed stereoselective acetylation of racemic 7-[N,N'-bis-(benzyloxy-carbonyl)N-(guanidinoheptanoyl)]-alpha-hydroxy-glycine 24 to corresponding S-(-)-acetate 25 was demonstrated. S-(-)-acetate 25 is a key intermediate for total chemical synthesis of (-)-15-deoxyspergualin 23, an immunosuppressive agent and antitumor antibiotic. Stereoselective microbial reduction of (1S)[3-chloro-2-oxo-1-(phenyl-methyl)propyl] carbamic acid, 1,1-dimethyl-ethyl ester 26 to corresponding chiral alcohol 27a (a key chiral intermediate for HIV protease inhibitors) was also demonstrated. Stereospecific enzymatic hydrolysis of racemic epoxide RS-1-[2',3'-dihydro benzo[b]furan-4'-yl]-1,2-oxirane 29 the corresponding R-diol 30 and unreacted chiral S-epoxide 28 was demonstrated using R. glutinis and A. niger. Dynamic resolution of racemic diol RS-1-[2',3'-dihydrobenzo[b]furan-4'-yl]-ethane-1,2-diol 32 to corresponding S-diol S-1-[2',3'-dihydrobenzo[b]furan-4'-yl]-ethane-1,2-diol 31 was demonstrated using C. boidinii and P. methanolica. Chiral (S)-epoxide 28 and (S)-diol 31 are key intermediates for a new prospective circadian modulator drug. Enzymatic resolution of racemic 2-pentanol and 2-heptanol by lipase B from Candida antarctica was demonstrated. S-(+)-2-pentanol is a key chiral intermediate required for synthesis of anti-Alzheimer's drugs.
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PMID:Microbial/enzymatic synthesis of chiral drug intermediates. 1287 94

THREE GROUPS OF PRIMARY INFLAMMATORY MUSCLE DISEASES: The primary inflammatory muscle diseases comprise three main subsets: polymyositis (PM), dermatomyositis (DM) and inclusion body myositis (IBM). PM and DM are characterized by a proximal weakness that develops along weeks to months and by elevated creatine phosphokinase levels. Cutaneous involvement including both erythema and edema and infantile or adult onset are DM specific. PM and IBM only concern adults. Several PM/DM manifestations must be searched for because of their severity: swallowing disorders, various mechanisms of respiratory dysfunction (swallowing pneumopathies, interstitial lung disease, respiratory muscle deficiency) and cardiac involvement. DIAGNOSTIC ELEMENTS FOR PM AND DM: Two investigations, beside biopsy, are particularly useful: muscle MRI imaging showing inflammatory pattern and specific detection of antisynthetase autoantibodies (PM/DM with interstitial lung disease) and anti-Mi-1 and 2 in DM. PHYSIOPATHOLOGICAL DATA: PM and DM differ in their histological and physiopathological characteristics: perivascular B and CD4 lymphocyte infiltrates and complement deposits at the origin of humoral induced vascular disease in DM and perimysial CD8 lymphocytes inducing a cellular mediated cytotoxic injury in PM. Class I HLA antigen expression on the muscle fibers and production of cytokines play a crucial role in the pathogenesis of these two diseases. PM and DM may be associated with cancers, connective-tissue disease (overlap syndrome). Some PM are secondary to HIV, HTLV1 virus and toxoplasmosis infection. CHARACTERISTICS OF INCLUSION BODY MYOSITIS: IBM, the most frequent acquired myopathy after 50 years of age, is characterized by particular features: not only clinical (late onset, selective weakness, early distal involvement, slow course, unresponsiveness to corticosteroid and immunosuppressant agents); but also histological (rimmed vacuoles, filamentous inclusions) and pathogenic (cytotoxic and degenerative inflammatory process, similar to Alzheimer's disease, with beta-amyloid protein accumulation).
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PMID:[Polymyositis, dermatomyositis and inclusion body myositis, nosological aspects]. 1463 Dec 70

Neurodegenerative diseases of the human brain comprise a variety of disorders that affect an increasing percentage of the population. Some of these are age dependent (e.g. Alzheimer's and Parkinson's diseases) and some are infection dependent, e.g. human immunodeficiency virus (HIV/AIDS). The vulnerable brain regions in HIV/AIDS individuals include the dentate nucleus in the cerebellum, the red nucleus, substantia nigra (SN) in the mid-brain, the subthalamic nucleus, thalamic fasciculus in the diencephalons, the globus pallidus and striatum (or neostriatum, which consists of caudate and putamen) in the forebrain. Lesion in these regions may lead to progressive dementia, which is similar to what is observed in Alzheimer's disease and Parkinson's disease. The entry of calcium into the cytoplasm of cells at concentrations that can activate oxidative enzymes such as phospholipase A(2) and xanthine oxidase, deplete cells of cysteine and glutathione, cause mitochondrial release of free radicals and cell death. Glutamate and its receptors are key molecular elements at the interface between neurons and glia. Dietary factors can modulate physiological functions (including brain function) thereby increasing the economic productivity of a population as a function of health. A greater understanding of the molecular mechanisms of neuroprotection, oxidative stress and immune function will facilitate definition of the prophylactic potentials of diet, nutritional/food supplements, medicinal plants and herbal extracts.
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PMID:Neuroprotection by bioactive components in medicinal and food plant extracts. 1464 22


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