Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Short-chain dehydrogenases/reductases (SDR) form a large, functionally heterogeneous protein family presently with about 3000 primary and about 30 3D structures deposited in databases. Despite low sequence identities between different forms (about 15-30%), the 3D structures display highly similar alpha/beta folding patterns with a central beta-sheet, typical of the Rossmann-fold. Based on distinct sequence motifs functional assignments and classifications are possible, making it possible to build a general nomenclature system. Recent mutagenetic and structural studies considerably extend the knowledge on the general reaction mechanism, thereby establishing a catalytic tetrad of Asn-Ser-Tyr-Lys residues, which presumably form the framework for a proton relay system including the 2'-OH of the nicotinamide ribose, similar to the mechanism found in horse liver ADH. Based on their cellular functions, several SDR enzymes appear as possible and promising pharmacological targets with application areas spanning hormone-dependent cancer forms or metabolic diseases such as obesity and diabetes, and infectious diseases.
 ...
PMID:Short-chain dehydrogenases/reductases (SDR): the 2002 update. 1260 10

Literature data and original experience of the authors with 6890 cases of respiratory sarcoidosis (stage I-III) suggest that diabetes ipsipidus in respiratory sarcoidosis (RS) can present as hypothalamic-hypophysial form (observed at the stage I-II by physicians since 1935) and a new form--nephrogenic (vasopressin-resistant) at stage II of pulmonary sarcoidosis. The latter form is little known. It was found that in stage III sarcoidosis patients who have severe fibrosis of the lungs and a long history of corticosteroid hormone treatment the nephrogenic form of the pathogenesis is caused by defects in calcium metabolism leading to nephrocalcinosis with low sensitivity of renal tubular receptors to ADH. Adiurecrine treatment is unefficient. It is recommended to use chlorpropamide which raises sensitivity of the tubules to ADH.
 ...
PMID:[Stage I-III pulmonary sarcoidosis complicated by nephrogenic (vasopressin-resistant) form of diabetes insipidus]. 1269 55

Aldo-keto reductases (AKRs) are NAD(P)H-dependent oxidoreductases that catalyse the reduction of a variety of carbonyl compounds, such as carbohydrates, aliphatic and aromatic aldehydes and steroids. We have studied the retinal reductase activity of human aldose reductase (AR), human small-intestine (HSI) AR and pig aldehyde reductase. Human AR and HSI AR were very efficient in the reduction of all- trans -, 9- cis - and 13- cis -retinal ( k (cat)/ K (m)=1100-10300 mM(-1).min(-1)), constituting the first cytosolic NADP(H)-dependent retinal reductases described in humans. Aldehyde reductase showed no activity with these retinal isomers. Glucose was a poor inhibitor ( K (i)=80 mM) of retinal reductase activity of human AR, whereas tolrestat, a classical AKR inhibitor used pharmacologically to treat diabetes, inhibited retinal reduction by human AR and HSI AR. All- trans -retinoic acid failed to inhibit both enzymes. In this paper we present the AKRs as an emergent superfamily of retinal-active enzymes, putatively involved in the regulation of retinoid biological activity through the assimilation of retinoids from beta-carotene and the control of retinal bioavailability.
 ...
PMID:Human aldose reductase and human small intestine aldose reductase are efficient retinal reductases: consequences for retinoid metabolism. 1273 97

Aldose-, aldehyde and renal specific oxido reductase (RSOR) belong to the family of aldo-keto reductases (AKRs). They are monomeric (alpha/beta)8-barrel proteins with a molecular weight ranging from 30 to 40 kDa, and at present include more than 60 members. Except for RSOR, they are expressed in a wide variety of animal and plant species and in various tissues. They catalyze NADPH-dependent reduction of various aliphatic and aromatic aldehyde and ketones. During the past three decades aldehyde reductase (AKR1A) and aldose reductase (AKR1B) have been extensively investigated, and the gene regulation of AKR1B has been noted to be heavily influenced by hyperglycemic state and high glucose ambience in various culture systems. AKR1B catalyzes the conversion of glucose to sorbitol in concert with a coenzyme, NADPH. The newly discovered RSOR has certain structural and functional similarities to AKR1B and seems to be relevant to the renal complications of diabetes mellitus. Like other AKRs, it has a NADPH binding motif, however, it is located at the N-terminus and it probably undergoes N-linked glycosylation in order to achieve functional substrate specificity. Besides the AKR3 motif, it has very little nucleotide or protein sequence homology with other members of the AKR family. Nevertheless, gene regulation of RSOR, like AKR1B, is heavily modulated by carbonyl, oxidative and osmotic stresses, and thus it is anticipated that its discovery would lead to the development of new inhibitors as well as gene therapy targets to alleviate the complications of diabetes mellitus in the future.
 ...
PMID:Gene regulation of aldose-, aldehyde- and a renal specific oxido reductase (RSOR) in the pathobiology of diabetes mellitus. 1287 Nov 37

Sorbitol dehydrogenase (SDH), a member of the medium-chain dehydrogenase/reductase protein family and the second enzyme of the polyol pathway of glucose metabolism, converts sorbitol to fructose strictly using NAD(+) as coenzyme. SDH is expressed almost ubiquitously in all mammalian tissues. The enzyme has attracted considerable interest due to its implication in the development of diabetic complications and thus its tertiary structure may facilitate the development of drugs for the treatment of diabetes sufferers. Modelling studies suggest that SDH is structurally homologous to mammalian alcohol dehydrogenase with respect to conserved zinc binding motif and a hydrophobic substrate-binding pocket. Recently, the three-dimensional (3-D) structure of a mammalian SDH was solved, and it was found that while the overall 3-D structures of SDH and alcohol dehydrogenase are similar, the zinc coordination in the active sites of the two enzymes is different. The available structural and biochemical information of SDH are currently being utilized in a structure-based approach to develop drugs for the treatment or prevention of the complications of diabetes. This review provides an overview of the recent advances in the structure, function and drug development fields of sorbitol dehydrogenase.
 ...
PMID:Sorbitol dehydrogenase: structure, function and ligand design. 1496 27

The crystal structures of porcine and human aldehyde reductase, an enzyme implicated in complications of diabetes, have been determined by X-ray diffraction methods. The crystallographic R factor for the refined porcine aldehyde reductase model is 0.19 at 2.8 A resolution. There are two molecules in the asymmetric unit related by a local non-crystallographic twofold axis. The human aldehyde reductase model has been refined to an R factor of 0.21 at 2.48 A resolution. The amino-acid sequence of porcine aldehyde reductase revealed a remarkable homology with human aldehyde reductase. The coenzyme-binding site residues are conserved and adopt similar conformations in human and porcine aldehyde reductase apo-enzymes. The tertiary structures of aldhyde reductase and aldose reductase are similar and consist of a beta/alpha-barrel, with the coenzyme-binding site located at the carboxy-terminus end of the strands of the barrel. The crystal structure of porcine and human aldehyde reductase should allow in vitro mutagenesis to elucidate the mechanism of action for this enzyme and facilitate the effective design of specific inhibitors.
 ...
PMID:Structures of human and porcine aldehyde reductase: an enzyme implicated in diabetic complications. 1529 53

Oxidation of ethanol via alcohol dehydrogenase (ADH) explains various metabolic effects of ethanol but does not account for the tolerance. This fact, as well as the discovery of the proliferation of the smooth endoplasmic reticulum (SER) after chronic alcohol consumption, suggested the existence of an additional pathway which was then described by Lieber and DeCarli, namely the microsomal ethanol oxidizing system (MEOS), involving cytochrome P450. The existence of this system was initially challenged but the effect of ethanol on liver microsomes was confirmed by Remmer and his group. After chronic ethanol consumption, the activity of the MEOS increases, with an associated rise in cytochrome P450, especially CYP2E1, most conclusively shown in alcohol dehydrogenase negative deer mice. There is also cross-induction of the metabolism of other drugs, resulting in drug tolerance. Furthermore, the conversion of hepatotoxic agents to toxic metabolites increases, which explains the enhanced susceptibility of alcoholics to the adverse effects of various xenobiotics, including industrial solvents. CYP2E1 also activates some commonly used drugs (such as acetaminophen) to their toxic metabolites, and promotes carcinogenesis. In addition, catabolism of retinol is accelerated resulting in its depletion. Contrasting with the stimulating effects of chronic consumption, acute ethanol intake inhibits the metabolism of other drugs. Moreover, metabolism by CYP2E1 results in a significant release of free radicals which, in turn, diminishes reduced glutathione (GSH) and other defense systems against oxidative stress which plays a major pathogenic role in alcoholic liver disease. CYP1A2 and CYP3A4, two other perivenular P450s, also sustain the metabolism of ethanol, thereby contributing to MEOS activity and possibly liver injury. CYP2E1 has also a physiologic role which comprises gluconeogenesis from ketones, oxidation of fatty acids, and detoxification of xenobiotics other than ethanol. Excess of these physiological substrates (such as seen in obesity and diabetes) also leads to CYP2E1 induction and nonalcoholic fatty liver disease (NAFLD), which includes nonalcoholic fatty liver and nonalcoholic steatohepatitis (NASH), with pathological lesions similar to those observed in alcoholic steatohepatitis. Increases of CYP2E1 and its mRNA prevail in the perivenular zone, the area of maximal liver damage. CYP2E1 up-regulation was also demonstrated in obese patients as well as in rat models of obesity and NASH. Furthermore, NASH is increasingly recognized as a precursor to more severe liver disease, sometimes evolving into "cryptogenic" cirrhosis. The prevalence of NAFLD averages 20% and that of NASH 2% to 3% in the general population, making these conditions the most common liver diseases in the United States. Considering the pathogenic role that up-regulation of CYP2E1 also plays in alcoholic liver disease (vide supra), it is apparent that a major therapeutic challenge is now to find a way to control this toxic process. CYP2E1 inhibitors oppose alcohol-induced liver damage, but heretofore available compounds are too toxic for clinical use. Recently, however, polyenylphosphatidylcholine (PPC), an innocuous mixture of polyunsaturated phosphatidylcholines extracted from soybeans (and its active component dilinoleoylphosphatidylcholine), were discovered to decrease CYP2E1 activity. PPC also opposes hepatic oxidative stress and fibrosis. It is now being tested clinically.
 ...
PMID:The discovery of the microsomal ethanol oxidizing system and its physiologic and pathologic role. 1555 33

Recent efforts to identify treatments for chronic diabetic complications have resulted in the discovery of a novel series of highly potent and selective 3-[(benzothiazol-2-yl)methyl]indole-N-alkanoic acid aldose reductase inhibitors. The lead candidate, 3-[(4,5,7-trifluorobenzothiazol-2-yl)methyl]indole-N-acetic acid (lidorestat, 9) inhibits aldose reductase with an IC(50) of 5 nM, while being 5400 times less active against aldehyde reductase, a related enzyme involved in the detoxification of reactive aldehydes. It lowers nerve and lens sorbitol levels with ED(50)'s of 1.9 and 4.5 mg/kg/d po, respectively, in the 5-day STZ-induced diabetic rat model. In a 3-month diabetic intervention model (1 month of diabetes followed by 2 months of drug treatment at 5 mg/kg/d po), it normalizes polyols and reduces the motor nerve conduction velocity deficit by 59% relative to diabetic controls. It has a favorable pharmacokinetic profile (F, 82%; t(1/2), 5.6 h; Vd, 0.694 L/kg) with good drug penetration in target tissues (C(max) in sciatic nerve and eye are 2.36 and 1.45 mug equiv/g, respectively, when dosed with [(14)C]lidorestat at 10 mg/kg po).
 ...
PMID:Discovery of 3-[(4,5,7-trifluorobenzothiazol-2-yl)methyl]indole-N-acetic acid (lidorestat) and congeners as highly potent and selective inhibitors of aldose reductase for treatment of chronic diabetic complications. 1585 20

Sialadenosis, also referred to as sialosis, is a disease of unknown aetiology. It regularly manifests itself as a massive swelling in both parotid regions involving the major salivary glands, preferably the parotid glands and is characterized by lack of any detectable, underlying pathologies. In this case report we describe a 24-year-old white female patient with diabetes insipidus who developed sialadenosis of the major salivary glands during a period of enhanced water requirement, which the patient tried to compensate for by more frequent nasal ADH application. Since ADH acts on aquaporins (AQPs) in the kidney, we were interested if AQP expression in the patients salivary glands was affected. Surprisingly, compared to normal control tissues we observed an extensively high signal for AQP5, which is the dominant AQP found in salivary acinar cells. Interestingly, previous studies on AQP5 knock out mice found AQP5 to be required for cell volume regulation. We therefore suggest that aquaporin water channels and antidiuretic hormone together with a disturbance in the body's water household are potential key-factors in the pathophysiological events leading to the development of the disease entity called sialadenosis.
Exp Clin Endocrinol Diabetes 2005 Apr
PMID:Sialadenosis of the major salivary glands in a patient with central diabetes insipidus--implications of aquaporin water channels in the pathomechanism of sialadenosis. 1589 55

The biguanides metformin and buformin, which are clinically used for diabetes mellitus, are known to improve resistance to insulin in patients. Biguanides were reported to cause lactic acidosis as a side effect. Since the mechanism of the side effect still remains obscure, we have examined genes whose expression changes by treating HepG2 cells with buformin in order to elucidate the mechanisms of the side effect. A subtraction cDNA library was constructed by the method of suppressive subtractive hybridization and the screening of the library was performed with cDNA probes prepared from HepG2 cells treated with or without buformin for 12 h. The expression of the gene and the protein obtained by the screening was monitored by real-time RT-PCR with specific primers and Western blotting with specific antibody. The amounts of ATP and NAD+ were determined with luciferase and alcohol dehydrogenase, respectively. We found that expression of the glyceraldehyde 3-phosphate dehydrogenase (GAPD) gene was suppressed by treating HepG2 cells with 0.25 mM buformin for 12 h as a result of the library screening. The decrease in the expression depended on the treatment period. The amount of GAPD protein also decreased simultaneously with the suppression of the gene expression by the treatment with buformin. The amount of ATP and NAD+ in the HepG2 cells treated with buformin decreased to 10 and 20% of the control, respectively. These observations imply that the biguanide causes deactivation of the glycolytic pathway and subsequently the accumulation of pyruvate and NADH and a decrease in NAD+. Therefore, the reaction equilibrium catalyzed by lactate dehydrogenase leans towards lactate production and this may result in lactic acidosis.
 ...
PMID:Buformin suppresses the expression of glyceraldehyde 3-phosphate dehydrogenase. 1665 35


<< Previous 1 2 3 4 5 6 7 8 Next >>