scholarly journals Spermidine/spermine-N1-acetyltransferase-2 (SSAT2) acetylates thialysine and is not involved in polyamine metabolism

2004 ◽  
Vol 384 (1) ◽  
pp. 139-148 ◽  
Author(s):  
Catherine S. COLEMAN ◽  
Bruce A. STANLEY ◽  
A. Daniel JONES ◽  
Anthony E. PEGG
Keyword(s):  
Urinary Metabolites ◽  
Polyamine Metabolism ◽  
Polyamine Analogues ◽  
Naturally Occurring ◽  
Polyamine Content ◽  
Turn Over ◽  
Nih 3T3 ◽  
The Brain ◽  
Acetylpolyamine Oxidase ◽  
Catabolic Enzyme

Spermidine/spermine-N1-acetyltransferase (SSAT1) is a short-lived polyamine catabolic enzyme inducible by polyamines and polyamine analogues. Induction of SSAT1 plays an important role in polyamine homoeostasis, since the N1-acetylated polyamines can be excreted or oxidized by acetylpolyamine oxidase. We have purified a recombinant human acetyltransferase (SSAT2) that shares 45% identity and 61% homology with human SSAT1, but is only distally related to other known members of the GNAT (GCN5-related N-acetyltransferase) family. Like SSAT1, SSAT2 is widely expressed, but did not turn over rapidly, and levels were unaffected by treatments with polyamine analogues. Despite similarity in sequence to SSAT1, polyamines were found to be poor substrates of purified SSAT2, having Km values in the low millimolar range and kcat values of <0.01 s−1. The kcat/Km values for spermine and spermidine for SSAT2 were <0.0003% those of SSAT1. Expression of SSAT2 in NIH-3T3 cells was not detrimental to growth, and did not reduce polyamine content or increase acetylpolyamines. These results indicate that SSAT2 is not a polyamine catabolic enzyme, and that polyamines are unlikely to be its natural intracellular substrates. A promising candidate for the physiological substrate of SSAT2 is thialysine [S-(2-aminoethyl)-L-cysteine], which is acetylated predominantly at the ε-amino group with Km and kcat values of 290 μM and 5.2 s−1. Thialysine is a naturally occurring modified amino acid that can undergo metabolism to form cyclic ketimine derivatives found in the brain and as urinary metabolites, which can undergo further reaction to form antioxidants. SSAT2 should be renamed ‘thialysine Nε-acetyltransferase’, and may regulate this pathway.

scholarly journals A perspective of polyamine metabolism

2003 ◽  
Vol 376 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Heather M. WALLACE ◽  
Alison V. FRASER ◽  
Alun HUGHES
Keyword(s):  
Tumour Cells ◽  
Polyamine Metabolism ◽  
Parasitic Infections ◽  
Proof Of Concept ◽  
Compensatory Mechanisms ◽  
Polyamine Analogues ◽  
Cellular Effects ◽  
Current Thinking ◽  
Polyamine Content ◽  
And Function

Polyamines are essential for the growth and function of normal cells. They interact with various macromolecules, both electrostatically and covalently and, as a consequence, have a variety of cellular effects. The complexity of polyamine metabolism and the multitude of compensatory mechanisms that are invoked to maintain polyamine homoeostasis argue that these amines are critical to cell survival. The regulation of polyamine content within cells occurs at several levels, including transcription and translation. In addition, novel features such as the +1 frameshift required for antizyme production and the rapid turnover of several of the enzymes involved in the pathway make the regulation of polyamine metabolism a fascinating subject. The link between polyamine content and human disease is unequivocal, and significant success has been obtained in the treatment of a number of parasitic infections. Targeting the polyamine pathway as a means of treating cancer has met with limited success, although the development of drugs such as DFMO (α-difluoromethylornithine), a rationally designed anticancer agent, has revolutionized our understanding of polyamine function in cell growth and provided ‘proof of concept’ that influencing polyamine metabolism and content within tumour cells will prevent tumour growth. The more recent development of the polyamine analogues has been pivotal in advancing our understanding of the necessity to deplete all three polyamines to induce apoptosis in tumour cells. The current thinking is that the polyamine inhibitors/analogues may also be useful agents in the chemoprevention of cancer and, in this area, we may yet see a revival of DFMO. The future will be in adopting a functional genomics approach to identifying polyamine-regulated genes linked to either carcinogenesis or apoptosis.

scholarly journals Effect of a Bis-Benzyl Polyamine Analogue onPneumocystis carinii

2000 ◽  
Vol 44 (2) ◽  
pp. 337-343 ◽  
Author(s):  
Salim Merali ◽  
Muhamed Sarić ◽  
Kevin Chin ◽  
Allen B. Clarkson
Keyword(s):  
Mammalian Cells ◽  
Pneumocystis Carinii ◽  
Specific Treatment ◽  
Polyamine Metabolism ◽  
Biosynthetic Enzyme ◽  
Polyamine Biosynthesis ◽  
Polyamine Analogues ◽  
Polyamine Content ◽  
Polyamine Analogue ◽  
Polyamine Transporter

ABSTRACT Pneumocystis carinii is the causative agent of P. carinii pneumonia (PCP), an opportunistic infection associated with AIDS and other immunosuppressed conditions. Although polyamine metabolism of this fungus has been shown to be a chemotherapeutic target, this metabolism has not been thoroughly investigated. Reported here is the effect of one polyamine analogue,N,N′-bis{3-[(phenylmethyl)amino]propyl}-1,7-diaminoheptane (BBS), on P. carinii. BBS inhibits the growth of P. carinii in culture, but at concentrations higher than those required to inhibit the growth of other pathogens. However, BBS is at least as active in an animal model of PCP as in other models of diseases studied. BBS causes some reduction in P. cariniipolyamine content and polyamine biosynthetic enzyme activities, but the effect is less than that observed with other pathogens and very much less than the effect of the polyamine biosynthesis inhibitordl-α-difluoromethylornithine. BBS enters P. carinii cells via a polyamine transporter, unlike all other cells that have been studied. P. carinii cells do not remove the benzyl groups of BBS, as is reported for mammalian cells. The most likely mode of action is displacement of natural polyamines. Overall, the activity of BBS provides further evidence that polyamines and polyamine metabolism are rational targets for the development of drugs to treat PCP. Because the details of BBS-P. cariniiinteraction differ from those of other cells studied, polyamine analogues may provide a highly specific treatment for PCP.

scholarly journals Polyamine analogues: potent inducers of nucleosomal array oligomerization and inhibitors of yeast cell growth

2007 ◽  
Vol 405 (3) ◽  
pp. 541-545 ◽  
Author(s):  
Lenny M. Carruthers ◽  
Laurence J. Marton ◽  
Craig L. Peterson
Keyword(s):  
Cell Growth ◽  
Yeast Cell ◽  
Higher Order ◽  
Polyamine Metabolism ◽  
Polyamine Analogues ◽  
Naturally Occurring ◽  
Nucleosomal Array ◽  
Carcinogenic Process

Polyamines are naturally occurring intracellular polycations that are essential for viability and growth of eukaryotes. Dysregulation of polyamine metabolism is a hallmark of cancer and the carcinogenic process, and consequently development of polyamine analogues has emerged as a viable strategy for therapeutic intervention. Previously, we showed that the naturally occurring polyamines spermidine and spermine were quite effective at inducing the oligomerization of nucleosomal arrays in vitro, suggesting that polyamines may play a key role in regulating higher order chromatin structures in vivo. Here, we analyse the ability of a number of synthetic polyamine analogues to potentiate formation of higher order chromatin structures in vitro. We find that a class of long-chain polyamines called oligoamines are potent inducers of nucleosomal array oligomerization in vitro and that these same polyamine analogues rapidly block yeast cell growth.

Brain Drug Delivery: Overcoming the Blood-brain Barrier to Treat Tauopathies

2020 ◽  
Vol 26 (13) ◽  
pp. 1448-1465 ◽  
Author(s):  
Jozef Hanes ◽  
Eva Dobakova ◽  
Petra Majerova
Keyword(s):  
Drug Delivery ◽  
Blood Brain Barrier ◽  
Neurodegenerative Disorders ◽  
Brain Barrier ◽  
Neuronal Function ◽  
Brain Drug Delivery ◽  
Naturally Occurring ◽  
Blood Brain ◽  
Traditional Approaches ◽  
The Brain

Tauopathies are neurodegenerative disorders characterized by the deposition of abnormal tau protein in the brain. The application of potentially effective therapeutics for their successful treatment is hampered by the presence of a naturally occurring brain protection layer called the blood-brain barrier (BBB). BBB represents one of the biggest challenges in the development of therapeutics for central nervous system (CNS) disorders, where sufficient BBB penetration is inevitable. BBB is a heavily restricting barrier regulating the movement of molecules, ions, and cells between the blood and the CNS to secure proper neuronal function and protect the CNS from dangerous substances and processes. Yet, these natural functions possessed by BBB represent a great hurdle for brain drug delivery. This review is concentrated on summarizing the available methods and approaches for effective therapeutics’ delivery through the BBB to treat neurodegenerative disorders with a focus on tauopathies. It describes the traditional approaches but also new nanotechnology strategies emerging with advanced medical techniques. Their limitations and benefits are discussed.

Role of Flavonoids in Neurodegenerative Disorders with Special Emphasis on Tangeritin

2019 ◽  
Vol 18 (8) ◽  
pp. 581-597 ◽  
Author(s):  
Ambreen Fatima ◽  
Yasir Hasan Siddique
Keyword(s):  
Medicinal Plants ◽  
Mechanism Of Action ◽  
Neurodegenerative Disorders ◽  
Treatment Strategies ◽  
Dietary Supplementation ◽  
Plant Polyphenols ◽  
Promising Candidate ◽  
Naturally Occurring ◽  
The Brain

Flavonoids are naturally occurring plant polyphenols found universally in all fruits, vegetables and medicinal plants. They have emerged as a promising candidate in the formulation of treatment strategies for various neurodegenerative disorders. The use of flavonoid rich plant extracts and food in dietary supplementation have shown favourable outcomes. The present review describes the types, properties and metabolism of flavonoids. Neuroprotective role of various flavonoids and the possible mechanism of action in the brain against the neurodegeneration have been described in detail with special emphasis on the tangeritin.

scholarly journals The Potential Effects of Phytoestrogens: The Role in Neuroprotection

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2954
Author(s):  
Justyna Gorzkiewicz ◽  
Grzegorz Bartosz ◽  
Izabela Sadowska-Bartosz
Keyword(s):  
Neuroprotective Effect ◽  
Antioxidant Properties ◽  
Estrogen Therapy ◽  
Neuroprotective Effects ◽  
Potential Health ◽  
Naturally Occurring ◽  
Epigenetic Effects ◽  
Estrogen Synthesis ◽  
Health Promoting ◽  
The Brain

Phytoestrogens are naturally occurring non-steroidal phenolic plant compounds. Their structure is similar to 17-β-estradiol, the main female sex hormone. This review offers a concise summary of the current literature on several potential health benefits of phytoestrogens, mainly their neuroprotective effect. Phytoestrogens lower the risk of menopausal symptoms and osteoporosis, as well as cardiovascular disease. They also reduce the risk of brain disease. The effects of phytoestrogens and their derivatives on cancer are mainly due to the inhibition of estrogen synthesis and metabolism, leading to antiangiogenic, antimetastatic, and epigenetic effects. The brain controls the secretion of estrogen (hypothalamus-pituitary-gonads axis). However, it has not been unequivocally established whether estrogen therapy has a neuroprotective effect on brain function. The neuroprotective effects of phytoestrogens seem to be related to both their antioxidant properties and interaction with the estrogen receptor. The possible effects of phytoestrogens on the thyroid cause some concern; nevertheless, generally, no serious side effects have been reported, and these compounds can be recommended as health-promoting food components or supplements.

scholarly journals Conceptual and Practical Issues in the Pharmacological Treatment of Brain Injury

1993 ◽  
Vol 4 (3) ◽  
pp. 227-237 ◽  
Author(s):  
Donald G. Stein ◽  
Marylou M. Glasier ◽  
Stuart W. Hoffman
Keyword(s):  
Central Nervous System ◽  
Brain Injury ◽  
Time Course ◽  
Chemical Activity ◽  
Behavioral Testing ◽  
Naturally Occurring ◽  
New Information ◽  
Definition Of ◽  
Injury And Repair ◽  
The Brain

It is only within the last ten years that research on treatment for central nervous system (CNS) recovery after injury has become more focused on the complexities involved in promoting recovery from brain injury when the CNS is viewed as an integrated and dynamic system. There have been major advances in research in recovery over the last decade, including new information on the mechanics and genetics of metabolism and chemical activity, the definition of excitotoxic effects and the discovery that the brain itself secretes complex proteins, peptides and hormones which are capable of directly stimulating the repair of damaged neurons or blocking some of the degenerative processes caused by the injury cascade. Many of these agents, plus other nontoxic naturally occurring substances, are being tested as treatment for brain injury. Further work is needed to determine appropriate combinations of treatments and optimum times of administration with respect to the time course of the CNS disorder. In order to understand the mechanisms that mediate traumatic brain injury and repair, there must be a merging of findings from neurochemical studies with data from intensive behavioral testing.

The topography, structure and incidence of mineralized bodies in the basal ganglia of the brain of cynomolgus monkeys (Macaca fascicularis)

1995 ◽  
Vol 29 (3) ◽  
pp. 276-281 ◽  
Author(s):  
P. F. Wadsworth ◽  
H. B. Jones ◽  
J. B. Cavanagh
Keyword(s):  
Basal Ganglia ◽  
Natural Occurrence ◽  
Optic Chiasma ◽  
Cynomolgus Monkeys ◽  
Small Vessels ◽  
Mammillary Bodies ◽  
Naturally Occurring ◽  
Toxicological Studies ◽  
One Year ◽  
The Brain

Whole coronal slices from 6 levels of the brain of 16 cynomolgus monkeys (8 control and 8 treated by daily gavage with a novel pharmaceutical agent for one year) were examined histologically. Mineralized bodies were identified only in coronal sections passing through the optic chiasma and mammillary bodies. Identical mineralized structures were present in the basal ganglia of both control and treated animals. The majority were seen in the globus pallidus, occasionally in the putamen and once in the nearby caudate nucleus. These structures were partially ferruginated and also partially calcified. They appeared to arise in relation to small vessels. They are part of the naturally occurring background pathology of several species of non-human primates and the incidence in this study (3/8 control and 5/8 treated) was approximately what might be expected from reports in the literature. Mineralized bodies of the basal ganglia of primates represent a spontaneous lesion with a characteristic distribution. They may cause confusion in interpretation of toxicological studies if their natural occurrence is not appreciated.

scholarly journals STUDIES ON THE PATHOGENESIS OF KERNICTERUS

1953 ◽  
Vol 98 (5) ◽  
pp. 509-520 ◽  
Author(s):  
F. Stephen Vogel
Keyword(s):  
Blood Brain Barrier ◽  
Neuronal Damage ◽  
Nerve Cells ◽  
Brain Barrier ◽  
Maximum Absorption ◽  
Naturally Occurring ◽  
Blood Brain ◽  
Absorption Of Light ◽  
The Brain

Kernicteric pigment was extracted by means of chloroform from the brains of 3 infants. Solutions of it gave a positive diazo reaction, and, as determined electrophotometrically, gave maximum absorption of light having a wavelength of 425 mµ, being identical in these properties with chloroform solutions of crystalline mesobilirubin. Experimental kernicterus was regularly induced by injecting crystalline mesobilirubin intracerebrally in newborn kittens, the pigment staining the cerebral tissues a bright canary-yellow and being deposited abundantly in the nerve cells, as microscopic examinations showed, although these latter were otherwise intact. Bilirubin, likewise injected intracerebrally in newborn kittens, had no such effects. The possibility is discussed that the blood-brain barrier is altered in some infants with hyperbilirubinemia in such a way that bilirubin crosses it and is then reduced within the brain to mesobilirubin thus giving rise to the cerebral pigmentation of kernicterus. The fact that the pigment itself does not seem to damage the neurons, as the present studies show, makes it necessary to seek some other cause for the neuronal damage that is sometimes seen, in association with the pigmentation, in the naturally occurring disease.

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