Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.4.2.30 (PARP)
 13,611 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Endogenous ADP-ribosylation of proteins was studied in retina crude extract, membrane and cytosolic fractions of control and diabetic rats. ADP-ribosyltransferase activity is present in all cellular fractions, but protein ADP-ribosylation is reduced in diabetic rat retina. At least 6 proteins are labelled in the crude extract fraction and a similar number in the membrane preparation of control animals. In these preparations from diabetic retina, only two bands were labelled, the 85 K and 36 K for the crude extract, and the 97 K and 39 K for membranes. Labelling of 36 K and 39 K proteins was much less than in controls. In the cytosolic preparations of controls, two proteins of 85 K and 39 K are ADP-ribosylated, while in diabetic rat retina cytosol, only the 85 K is labelled. Treatment of diabetic rats with insulin normalized plasma glucose levels and prevented the alterations of the extent of ADP-ribosylation for the 38 K cytosolic, 39 K membrane and 36 K crude extracts proteins, but it failed to affect the other bands. These results suggest a hyperactivity of endogenous ADP-ribosylases in diabetic rat retina, so that the protein sites for ADP-ribosylation are no longer available. Since insulin treatment prevents the onset of neuropathy and of retinal G protein impairment (Abbracchio et al., J Neurosci Res 29:196-220, 1991) in diabetic rats and, in this study, normalizes ADP-ribosylation of 39 K, 38 K and 36 K proteins, we suggest that the abnormal endogenous ADP-ribosylation of these proteins might play a role in the onset of diabetic neuropathy.
 ...
PMID:Nitric oxide-sensitive protein ADP-ribosylation is altered in rat diabetic neuropathy. 774 37

This study monitored the extranuclear endogenous mono ADP-ribosylation of proteins. At least 10 proteins were ADP-ribosylated in a crude extract from control superior cervical ganglia, and 7 were labeled in control dorsal root ganglia; whereas in the diabetic rat the extent of labeling was reduced. These data suggest that proteins of peripheral ganglia are excessively ADP-ribosylated in vivo. Treatment of diabetic animals with silybin, a flavonoid with ADP-ribosyltransferase inhibitory activity, did not affect hyperglycemia, but prevented the alterations in the extent of mono-ADP-ribosylation of proteins. This effect was associated with the prevention of substance P-like immunoreactivity loss in the sciatic nerve. In the membrane fraction of sciatic nerve Schwann cells, at least 9 proteins were ADP-ribosylated, in diabetic rats the extent of labeling was increased. A comparable increase involving the same proteins was triggered by chronic nerve injury and by corticosteroid treatment. Silybin treatment of diabetic rats prevented such an increase. We propose that the inhibition of excessive protein mono-ADP-ribosylation by silybin prevented the onset of diabetic neuropathy, while the silybin effect on mono-ADP-ribosylation of Schwann cells is likely indirect and secondary to the improvement of diabetic axonopathy.
 ...
PMID:Alterations of protein mono-ADP-ribosylation and diabetic neuropathy: a novel pharmacological approach. 888 32

Oxidative and nitrosative stress play a key role in the pathogenesis of diabetic neuropathy, but the mechanisms remain unidentified. Here we provide evidence that poly(ADP-ribose) polymerase (PARP) activation, a downstream effector of oxidant-induced DNA damage, is an obligatory step in functional and metabolic changes in the diabetic nerve. PARP-deficient (PARP(-/-)) mice were protected from both diabetic and galactose-induced motor and sensory nerve conduction slowing and nerve energy failure that were clearly manifest in the wild-type (PARP(+/+)) diabetic or galactose-fed mice. Two structurally unrelated PARP inhibitors, 3-aminobenzamide and 1,5-isoquinolinediol, reversed established nerve blood flow and conduction deficits and energy failure in streptozotocin-induced diabetic rats. Sciatic nerve immunohistochemistry revealed enhanced poly(ADP-ribosyl)ation in all experimental groups manifesting neuropathic changes. Poly(ADP-ribose) accumulation was localized in both endothelial and Schwann cells. Thus, the current work identifies PARP activation as an important mechanism in diabetic neuropathy and provides the first evidence for the potential therapeutic value of PARP inhibitors in this devastating complication of diabetes.
 ...
PMID:Role of poly(ADP-ribose) polymerase activation in diabetic neuropathy. 1498 56

Poly(ADP-ribose) polymerase (PARP) inhibition has recently been identified as a novel approach to treatment of experimental peripheral diabetic neuropathy (PDN). However, long-term inhibition of PARP, an enzyme involved in DNA repair, can potentially result in premature aging, loss of genome stability, and other side effects. This study evaluated potential synergistic interactions between low doses of the potent and specific PARP inhibitor 1,5-isoquinolinediol (ISO) and one of two vasodilators, the ACE inhibitor lisinopril (LIS) and the beta2-adrenoceptor agonist salbutamol (SAL) in the model of early PDN. Control and streptozotocin (STZ)-induced diabetic rats were treated with either ISO plus LIS or ISO plus SAL for 2 weeks after an initial 2 weeks without treatment. ISO (intraperitoneally) and LIS and SAL (both in the drinking water) were used in subtherapeutic doses, resulting in a minor correction of diabetes-associated sciatic motor and hind-limb digital sensory nerve conduction deficits when administered as monotherapies. Both combination treatments corrected endoneurial blood flow and vascular conductance deficits in STZ-induced diabetic rats. ISO plus SAL corrected all other changes of PDN, i.e., motor nerve conduction velocity (MNCV) and sensory nerve conduction velocity (SNCV) deficits as well as thermal and mechanical hyperalgesia. With ISO plus LIS, no significant correction of MNCV was observed, and the effect on thermal hyperalgesia was quite modest. SNCV and mechanical hyperalgesia were corrected. In vitro studies in human endothelial and Schwann cells showed early accumulation of poly(ADP-ribosyl)ated proteins (Western blot analysis) in response to high glucose, thus suggesting the importance of PARP activation in human PDN. In conclusion, low-dose PARP inhibitor-containing combination therapies may constitute a new approach for treatment of PDN.
 ...
PMID:Low-dose poly(ADP-ribose) polymerase inhibitor-containing combination therapies reverse early peripheral diabetic neuropathy. 1585 40

Poly(ADP-ribose) polymerase (PARP) activation is emerging as a fundamental mechanism in the pathogenesis of diabetes complications including diabetic neuropathy. This study evaluated the role of PARP in diabetic sensory neuropathy. The experiments were performed in control and streptozotocin-induced diabetic rats treated with or without the PARP inhibitor 1,5-isoquinolinediol (ISO; 3 mg x kg(-1) x day(-1) i.p.) for 2 weeks after 2 weeks without treatment. Diabetic rats developed thermal hyperalgesia (assessed by paw-withdrawal and tail-flick tests), mechanical hyperalgesia (von Frey anesthesiometer/rigid filaments and Randall-Sellito tests), tactile allodynia (flexible von Frey filaments), and increased flinching behavior in phases 1 and 2 of the 2% formalin pain test. They also had clearly manifest increase in nitrotyrosine and poly(ADP-ribose) immunoreactivities in the sciatic nerve and increased superoxide formation (hydroxyethidine method) and nitrotyrosine immunoreactivity in vasa nervorum. ISO treatment alleviated abnormal sensory responses, including thermal and mechanical hyperalgesia and tactile allodynia as well as exaggerated formalin flinching behavior in diabetic rats, without affecting the aforementioned variables in the control group. Poly(ADP-ribose) and, to a lesser extent, nitrotyrosine abundance in sciatic nerve, as well as superoxide and nitrotyrosine formation in vasa nervorum, were markedly reduced by ISO therapy. Apoptosis in dorsal root ganglion neurons (transferase-mediated dUTP nick-end labeling assay) was not detected in any of the groups. In conclusion, PARP activation contributes to early diabetic sensory neuropathy by mechanisms that may include oxidative stress but not neuronal apoptosis.
 ...
PMID:Poly(ADP-ribose) polymerase inhibition alleviates experimental diabetic sensory neuropathy. 1673 31

Evidence that poly(ADP-ribose) polymerase (PARP) activation plays an important role in diabetic complications is emerging. This study evaluated the role of PARP in rat and mouse models of advanced diabetic neuropathy. The orally active PARP inhibitor 10-(4-methylpiperazin-1-ylmethyl)-2H-7-oxa-1,2-diaza-benzo[de]anthracen-3-one (GPI-15427; formulated as a mesilate salt, 30 mg kg(-1) day(-1) in the drinking water for 10 weeks after the first 2 weeks without treatment) at least partially prevented PARP activation in peripheral nerve and DRG neurons, as well as thermal hypoalgesia, mechanical hyperalgesia, tactile allodynia, exaggerated response to formalin, and, most importantly, intraepidermal nerve fiber degeneration in streptozotocin-diabetic rats. These findings are consistent with the lack of small sensory nerve fiber dysfunction in diabetic PARP -/- mice. Furthermore, whereas diabetic PARP +/+ mice displayed approximately 46% intraepidermal nerve fiber loss, diabetic PARP -/- mice retained completely normal intraepidermal nerve fiber density. In conclusion, PARP activation is an important contributor to intraepidermal nerve fiber degeneration and functional changes associated with advanced Type 1 diabetic neuropathy. The results support a rationale for the development of potent and low-toxicity PARP inhibitors and PARP inhibitor-containing combination therapies.
 ...
PMID:PARP inhibition or gene deficiency counteracts intraepidermal nerve fiber loss and neuropathic pain in advanced diabetic neuropathy. 1819 75

Poly(ADP-ribose) polymerase-1 (PARP-1) is an ubiquitous DNA-binding protein involved in the cellular response to various genotoxic agents. Excessive PARP-1 activation is known to lead to the depletion of intracellular NAD+ and ATP pools and hence to threat cell survival. Therefore, PARP-1 could be involved in neuronal death and contribute to the development of diabetic polyneuropathy (DPN). This study addressed the association of Leu54Phe and Val762Ala polymorphisms of PARP-1 with DPN in Russian type 1 diabetic (T1D) patients. Eighty-six T1D patients with severe DPN and 93 T1D patients with no clinical signs of DPN have been studied by a polymerase chain reaction restriction fragment length polymorphism approach. Using Fisher's exact test revealed the association of the Phe54 and Val762 variants of PARP-1 (odds ratio (OR), 1.66 and 2.88, respectively) with increased risk of DPN in T1D. These results suggest that the PARP1 gene is involved in the pathogenesis of diabetic neuropathy in a Russian population. Additionally, a logistic regression analysis revealed a significant association between the neurological variances such as vibration detection threshold (OR, 2.08), vibration and temperature perception thresholds (OR, 1.32 and 1.67, respectively), and sensory and motor nerve conduction velocities (OR, 2.34 and 2.58, respectively), with DPN.
 ...
PMID:Leu54Phe and Val762Ala polymorphisms in the poly(ADP-ribose)polymerase-1 gene are associated with diabetic polyneuropathy in Russian type 1 diabetic patients. 1805 8

Peripheral diabetic neuropathy is a heterogeneous group of disorders, and is known to affect 50-60% of diabetic patients. Poly (ADP-ribose) polymerase (PARP) activation has been identified as one of the key components in the pathogenesis of diabetic neuropathy. In the present study we have targeted PARP overactivation in diabetic neuropathy using a known PARP inhibitor, 4 amino 1, 8-napthalimide (4-ANI). Streptozotocin induced diabetic rats developed neuropathy within 6 weeks, which was evident from significant reduction in motor nerve conduction velocity (MNCV), nerve blood flow (NBF) along with neuropathic pain and abnormal sensory perception. Six weeks after diabetes induction Sprague Dawley rats were treated with 4-ANI (3 and 10 mg/kg, p.o.) for a period of two weeks (seventh and eighth weeks). Two week treatment with 4-ANI showed improvement in nerve conduction, nerve blood flow and reduction in tail flick responses and mechanical allodynia in diabetic animals. 4-ANI also attenuated PAR immunoreactivity and NAD depletion in nerves of diabetic animals. Results of present study suggest the potential of PARP inhibitors like 4-ANI in the treatment of diabetic neuropathy.
 ...
PMID:Protective effects of 4-amino1,8-napthalimide, a poly (ADP-ribose) polymerase inhibitor in experimental diabetic neuropathy. 1826 71

Peroxynitrite mediated nitrosative stress, an indisputable initiator of DNA damage and overactivation of poly(ADP-ribose) polymerase (PARP), a nuclear enzyme activated after sensing DNA damage, are two crucial pathogenetic mechanisms in diabetic neuropathy. The intent of the present study was to investigate the effect of combination of a peroxynitrite decomposition catalyst (PDC), FeTMPyP and a PARP inhibitor, 4-ANI against diabetic peripheral neuropathy. The end points of evaluation of the study included motor nerve conduction velocity (MNCV) and nerve blood flow (NBF) for evaluating nerve functions; thermal hyperalgesia and mechanical allodynia for assessing nociceptive alterations, malondialdehyde and peroxynitrite levels to detect oxidative stress-nitrosative stress; NAD concentration in sciatic nerve to assess overactivation of PARP. Additionally immunohistochemical studies for nitrotyrosine and Poly(ADP-ribose) (PAR) was also performed. Treatment with the combination of FeTMPyP and 4-ANI led to significant improvement in nerve functions and pain parameters and also attenuated the oxidative-nitrosative stress markers. Further, the combination also reduced the overactivation of PARP as evident from increased NAD levels and decreased PAR immunopositivity in sciatic nerve microsections. Thus, it can be concluded that treatment with the combination of a PDC and PARP inhibitor attenuates alteration in peripheral nerves in diabetic neuropathy (DN).
 ...
PMID:Concurrent targeting of nitrosative stress-PARP pathway corrects functional, behavioral and biochemical deficits in experimental diabetic neuropathy. 1990 Apr 2

Oxidative stress resulting in excessive generation of ROS is a compelling initiator of DNA damage along with damage to various cellular proteins and other macromolecules. Poly(ADP-ribose) polymerase (PARP) activation in response to DNA damage, stirs an energy-consuming cellular metabolic cycle; culminating into cell death. The present study was designed to determine the effect of combining an antioxidant, Melatonin and a PARP inhibitor, Nicotinamide on the hallmark deficits developing in diabetic neuropathy (DN). Streptozotocin (STZ, 55 mg/kg, i.p.) was administered to induce diabetes. Six weeks post diabetes induction, two week treatment with Melatonin (3 and 10 mg/kg) and Nicotinamide (100 and 300 mg/kg) either alone or in combination was given. Effect of these interventions on the functional, behavioral and biochemical changes caused by hyperglycemia were studied in treated animals. Melatonin and Nicotinamide alone as well as in combination ameliorated the functional deficits along with improvement in pain parameters. The combination also demonstrated an essential reversal of biochemical alterations. Nitrotyrosine and Poly ADP Ribose (PAR) immunopositivity was significantly decreased in sciatic nerve micro-sections of treatment group. The results of this study advocate that simultaneous inhibition of oxidative stress-PARP activation cascade may prove useful for the pharmacotherapy of DN.
 ...
PMID:Functional and biochemical evidence indicating beneficial effect of Melatonin and Nicotinamide alone and in combination in experimental diabetic neuropathy. 2000 37


1 2 Next >>