The Role of Neurotransmitters in Protection against Amyloid- β Toxicity by KiSS-1 Overexpression in SH-SY5Y Neurons

Intranasal Oxytocin Attenuates Cognitive Impairment, β-Amyloid Burden and Tau Deposition in Female Rats with Alzheimer's Disease: Interplay of ERK1/2/GSK3β/Caspase-3

Oxytocin is a neuropeptide hormone that plays an important role in social bonding and behavior. Recent studies indicate that oxytocin could be involved in the regulation of neurological disorders. However, its role in modulating cognition in Alzheimer’s disease (AD) has never been explored. Hence, the present study aims to investigate the potential of chronic intranasal oxytocin in halting memory impairment & AD pathology in aluminum chloride-induced AD in female rats. Morris water maze was used to assess cognitive dysfunction in two-time points throughout the treatment period. In addition, neuroprotective effects of oxytocin were examined by assessing hippocampal acetylcholinesterase activity, β-amyloid 1–42 protein, and Tau levels. In addition, ERK1/2, GSK3β, and caspase-3 levels were assessed as chief neurobiochemical mediators in AD. Hippocampi histopathological changes were also evaluated. These findings were compared to the standard drug galantamine alone and combined with oxytocin. Results showed that oxytocin restored cognitive functions and improved animals’ behavior in the Morris test. This was accompanied by a significant decline in acetylcholinesterase activity, 1–42 β-amyloid and Tau proteins levels. Hippocampal ERK1/2 and GSK3β were also reduced, exceeding galantamine effects, thus attenuating AD pathological hallmarks formation. Determination of caspase-3 revealed low cytoplasmic positivity, indicating the ceasing of neuronal death. Histopathological examination confirmed these findings, showing restored hippocampal cells structure. Combined galantamine and oxytocin treatment showed even better biochemical and histopathological profiles. It can be thus concluded that oxytocin possesses promising neuroprotective potential in AD mediated via restoring cognition and suppressing β-amyloid, Tau accumulation, and neuronal death.

Kisspeptin-10 Rescues Cholinergic Differentiated SHSY-5Y Cells from α-Synuclein-Induced Toxicity In Vitro

The neuropathological substrate of dementia with Lewy bodies (DLB) is defined by the inextricable cross-seeding accretion of amyloid-β (Aβ) and α-synuclein (α-syn)-laden deposits in cholinergic neurons. The recent revelation that neuropeptide kisspeptin-10 (KP-10) is able to mitigate Aβ toxicity via an extracellular binding mechanism may provide a new horizon for innovative drug design endeavors. Considering the sequence similarities between α-syn’s non-amyloid-β component (NAC) and Aβ’s C-terminus, we hypothesized that KP-10 would enhance cholinergic neuronal resistance against α-syn’s deleterious consequences through preferential binding. Here, human cholinergic SH-SY5Y cells were transiently transformed to upsurge the mRNA expression of α-syn while α-syn-mediated cholinergic toxicity was quantified utilizing a standardized viability-based assay. Remarkably, the E46K mutant α-syn displayed elevated α-syn mRNA levels, which subsequently induced more cellular toxicity compared with the wild-type α-syn in choline acetyltransferase (ChAT)-positive cholinergic neurons. Treatment with a high concentration of KP-10 (10 µM) further decreased cholinergic cell viability, while low concentrations of KP-10 (0.01–1 µM) substantially suppressed wild-type and E46K mutant α-syn-mediated toxicity. Correlating with the in vitro observations are approximations from in silico algorithms, which inferred that KP-10 binds favorably to the C-terminal residues of wild-type and E46K mutant α-syn with CDOCKER energy scores of −118.049 kcal/mol and −114.869 kcal/mol, respectively. Over the course of 50 ns simulation time, explicit-solvent molecular dynamics conjointly revealed that the docked complexes were relatively stable despite small-scale fluctuations upon assembly. Taken together, our findings insinuate that KP-10 may serve as a novel therapeutic scaffold with far-reaching implications for the conceptualization of α-syn-based treatments.

A Structured Brain-wide and Genome-wide Association Study Using ADNI PET Images

A multi-stage variable selection method is introduced for detecting association signals in structured brain-wide and genome-wide association studies (brain-GWAS). Compared to conventional single-voxel-to-single-SNP approaches, our approach is more efficient and powerful in selecting the important signals by integrating anatomic and gene grouping structures in the brain and the genome, respectively. It avoids large number of multiple comparisons while effectively controls the false discoveries. Validity of the proposed approach is demonstrated by both theoretical investigation and numerical simulations. We apply the proposed method to a brain-GWAS using ADNI PET imaging and genomic data. We confirm previously reported association signals and also find several novel SNPs and genes that either are associated with brain glucose metabolism or have their association significantly modified by Alzheimer's disease status.

Nanoparticle encapsulated oxytocin increases resistance to induced seizures and restores social behavior in Scn1a-derived epilepsy

Oxytocin (OT) has broad effects in the brain and plays an important role in cognitive, social, and neuroendocrine function. OT has also been identified as potentially therapeutic in neuropsychiatric disorders such as autism and depression, which are often comorbid with epilepsy, raising the possibility that it might confer protection against the behavioral and seizure phenotypes in epilepsy. Dravet syndrome (DS) is an early-life encephalopathy associated with prolonged and recurrent early-life febrile seizures (FSs), treatment-resistant afebrile epilepsy, and cognitive and behavioral deficits. De novo loss-of-function mutations in the voltage-gated sodium channel SCN1A are the main cause of DS, while genetic epilepsy with febrile seizures plus (GEFS+), also characterized by early-life FSs and afebrile epilepsy, is typically caused by inherited mutations that alter the biophysical properties of SCN1A. Despite the wide range of available antiepileptic drugs, many patients with SCN1A mutations do not achieve adequate seizure control or the amelioration of associated behavioral comorbidities. In the current study, we demonstrate that nanoparticle encapsulation of OT conferred robust and sustained protection against induced seizures and restored more normal social behavior in a mouse model of Scn1a-derived epilepsy. These results demonstrate the ability of a nanotechnology formulation to significantly enhance the efficacy of OT. This approach will provide a general strategy to enhance the therapeutic potential of additional neuropeptides in epilepsy and other neurological disorders.

KISS1 in metastatic cancer research and treatment: potential and paradoxes

The significance of KISS1 goes beyond its original discovery as a metastasis suppressor. Its function as a neuropeptide involved in diverse physiologic processes is more well studied. Enthusiasm regarding KISS1 has cumulated in clinical trials in multiple fields related to reproduction and metabolism. But its cancer therapeutic space is unsettled. This review focuses on collating data from cancer and non-cancer fields in order to understand shared and disparate signaling that might inform clinical development in the cancer therapeutic and biomarker space. Research has focused on amino acid residues 68-121 (kisspeptin 54), binding to the KISS1 receptor and cellular responses. Evidence and counterevidence regarding this canonical pathway require closer look at the covariates so that the incredible potential of KISS1 can be realized.

Roles of the kisspeptin/GPR54 system in pathomechanisms of atherosclerosis

AIMS

Kisspeptin-10 (KP-10), a potent vasoconstrictor and inhibitor of angiogenesis, and its receptor, GPR54, have currently received much attention with respect to atherosclerosis, since both KP-10 and GPR54 are expressed at high levels in atheromatous plaques and restenotic lesions after wire-injury. The present review introduces the emerging roles of the KP-10/GPR54 system in atherosclerosis.

DATA SYNTHESIS

KP-10 suppresses migration and proliferation of human umbilical vein endothelial cells (HUVECs), and induces senescence in HUVECs. KP-10 increases adhesion of human monocytes to HUVECs. KP-10 also stimulates expression of interleukin-6, tumor necrosis factor-α, monocyte chemotactic protein-1, intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and E-selectin genes in HUVECs. KP-10 enhances oxidized low-density lipoprotein-induced foam cell formation associated with upregulation of CD36 and acyl-coenzyme A: cholesterol acyltransferase-1 in human monocyte-derived macrophages. In human aortic smooth muscle cells, KP-10 suppresses angiotensin II-induced migration and proliferation, however, it enhances apoptosis and activities of matrix metalloproteinase (MMP)-2 and MMP-9 by upregulation of extracellular signal-regulated kinase 1/2, p38, Bax, and caspase-3. Four-week-infusion of KP-10 into Apoe^-/- mice accelerates development of aortic atherosclerotic lesions with increased monocyte/macrophage infiltration and vascular inflammation, also, it decreases intraplaque vascular smooth muscle cell content. Proatherosclerotic effects of endogenous and exogenous KP-10 were completely attenuated upon infusion of P234, a GPR54 antagonist, in Apoe^-/- mice.

CONCLUSION

These findings suggest that KP-10 may contribute to acceleration of progression and to the instability of atheromatous plaques, leading to rupture of plaques. This GPR54 antagonist may be useful for the prevention and treatment of atherosclerosis. Thus, the KP-10/GPR54 system may serve as a novel therapeutic target for atherosclerotic diseases.

Role of the tumor microenvironment in regulating the anti-metastatic effect of KISS1

KISS1, a metastasis suppressor gene, has been shown to block metastasis without affecting primary tumor formation. Loss of KISS1 leads to invasion and metastasis in multiple cancers, which is the leading cause of cancer morbidity and mortality. The discovery of KISS1 has provided a ray of hope for early clinical diagnosis and for designing effective treatments targeting metastatic cancer. However, this goal requires greater holistic understanding of its mechanism of action. In this review, we go back into history and highlight some key developments, from the discovery of KISS1 to its role in regulating multiple physiological processes including cancer. We discuss key emerging roles for KISS1, specifically interactions with tissue microenvironment to promote dormancy and regulation of tumor cell metabolism, acknowledged as some of the key players in tumor progression and metastasis. We finally discuss strategies whereby KISS1 might be exploited clinically to treat metastasis.

The kisspeptin derivative kissorphin reduces the acquisition, expression, and reinstatement of ethanol-induced conditioned place preference in rats

Research has shown that opioids are involved in the rewarding effects of ethanol. Neuropeptide FF (NPFF) has been described as an anti-opioid peptide because, in many cases, it inhibits opioid and ethanol effects in rodents. Kissorphin (KSO) is a new peptide derived from kisspeptin-10 with structural similarities to NPFF. This peptide possesses NPFF-like biological activity in vitro. The aim of the current study was to investigate whether KSO (Tyr-Asn-Trp-Asn-Ser-Phe-NH2) influences the acquisition, expression, and reinstatement of ethanol-induced conditioned place preference (ethanol-CPP) in rats. The ethanol-CPP was established (conditioning for 5 days) by intraperitoneal (i.p.) administration of ethanol (1 g/kg, 20%, w/v) using an unbiased procedure. After that, one group of rats was used in final post-conditioning testing (expression of CPP) and the other group received a priming injection of ethanol after 10 days of extinction (reinstatement of CPP). Our experiments showed that KSO, given intravenously (i.v.) at the doses of 1, 3, and 10 nmol before every ethanol administration, inhibited the acquisition and, given acutely before the post-conditioning test or before the priming dose of ethanol, inhibited the expression and reinstatement of ethanol-CPP, respectively, in a dose-dependent manner. KSO given by itself neither induced place preference nor aversion and did not alter locomotor activity and coordination of rats. These results suggest that KSO can alter rewarding/motivational effects of ethanol. These data suggest this peptide possesses an anti-opioid character.

Search of Neuroprotective Polyphenols Using the "Overlay" Isolation Method

Previous studies of the neuroprotective activity of polyphenols have used ununiform culture systems, making it difficult to compare their neuroprotective potency. We have established a new and simple method for preparing differentiated PC12 cells by removing the toxic coating step. Cells were induced to differentiate with the nerve growth factor (NGF) in a serum-free medium, without a medium change, but with a one-time overlay supplementation of NGF. The optimal inoculation density of the cells was 6–12 × 10³ cells/cm², and the presence of serum inhibited the differentiation. Neuroprotective activity could be quantified by the specific index (SI) value, that is, the ratio of the 50% cytotoxic concentration to the 50% effective concentration. Alkaline extract from the leaves of Sasa senanensis Rehder (SE), having had hormetic growth stimulation, showed the highest SI value, followed by epigallocatechin gallate. The SI value of curcumin and resveratrol was much lower. This simple overly method, that can prepare massive differentiated neuronal cells, may be applicable for the study of the differentiation-associated changes in intracellular metabolites, and the interaction between neuronal cells and physiological factors.

Change in Anticancer Drug Sensitivity During Neuronal Differentiation of PC12 Cells

BACKGROUND/AIM

Although there are many reports of anticancer drug-induced neurotoxicity, most previous data have been derived from neuronal cell models grown in a variety of culture conditions. This has prevented accurate assessment of the potency of their neurotoxicity and of changes in drug sensitivity of neuronal cells during differentiation. In this study, a simple neuronal differentiation induction system was established and the relative potency of neurotoxicity of eight anticancer drugs was compared during neuronal cell differentiation.

MATERIALS AND METHODS

Rat PC12 cells were induced to differentiate into neuronal cells by 50 ng/ml nerve growth factor in serum-free Dulbecco's modified Eagle's medium, followed by overlay of fresh nutrients at day 3, without medium change. Cell viability was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method.

RESULTS

During differentiation, PC12 cells became 1.1-to more than 10,000-fold resistant to anticancer drugs. Topoisomerase inhibitors (doxorubicin, SN-38, etoposide) were the most toxic to differentiated PC12 cells, followed by docetaxel, gefitinib, melphalan, 5-fluorouracil and methotrexate. Docetaxel showed the highest cytotoxicity against undifferentiated PC12 cells, but its cytotoxicity was dramatically reduced during differentiation.

CONCLUSION

The present study demonstrated considerable variation in the neurotoxicity of anticancer drugs during the cell differentiation process. The present simple assay system may be useful to search for neuroprotective substances.

Change in Anticancer Drug Sensitivity During Neuronal Differentiation of PC12 Cells

BACKGROUND/AIM

Although there are many reports of anticancer drug-induced neurotoxicity, most previous data have been derived from neuronal cell models grown in a variety of culture conditions. This has prevented accurate assessment of the potency of their neurotoxicity and of changes in drug sensitivity of neuronal cells during differentiation. In this study, a simple neuronal differentiation induction system was established and the relative potency of neurotoxicity of eight anticancer drugs was compared during neuronal cell differentiation.

MATERIALS AND METHODS

Rat PC12 cells were induced to differentiate into neuronal cells by 50 ng/ml nerve growth factor in serum-free Dulbecco's modified Eagle's medium, followed by overlay of fresh nutrients at day 3, without medium change. Cell viability was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method.

RESULTS

During differentiation, PC12 cells became 1.1-to more than 10,000-fold resistant to anticancer drugs. Topoisomerase inhibitors (doxorubicin, SN-38, etoposide) were the most toxic to differentiated PC12 cells, followed by docetaxel, gefitinib, melphalan, 5-fluorouracil and methotrexate. Docetaxel showed the highest cytotoxicity against undifferentiated PC12 cells, but its cytotoxicity was dramatically reduced during differentiation.

CONCLUSION

The present study demonstrated considerable variation in the neurotoxicity of anticancer drugs during the cell differentiation process. The present simple assay system may be useful to search for neuroprotective substances.

Protection of Differentiating Neuronal Cells from Amyloid β Peptide-induced Injury by Alkaline Extract of Leaves of Sasa senanensis Rehder

BACKGROUND/AIM

We have previously reported the protection of doxorubicin-induced keratinocyte toxicity by alkaline extract of the leaves of Sasa senanensis Rehder (SE). In order to extend the generality of the cell protective effect of SE, we investigated whether it also protects rat PC12 and human SH-SY5Y neuron model cells from amyloid β-peptide (Aβ)-induced injury.

MATERIALS AND METHODS

Viability of cells was determined by the MTT method. Cytotoxicity was evaluated by the concentration that reduces the cell viability by 50% (CC50). Protection from Aβ-induced cytotoxicity was evaluated by the concentration that reversed the Aβ-induced reduction of viability by 50% (EC50). The selectivity index (SI) of neuroprotective activity was defined as the ratio of EC50 to CC50 Aβ1-42 aggregation was assayed using Aβ1-42 ammonium hydroxide.

RESULTS

SE showed hormetic growth stimulation at lower concentrations in both neuron precursors and differentiated cells. SE reproducibly inhibited Aβ-induced cytotoxicity against both undifferentiated and differentiated neuron cells. Both the extent of differentiation induction and viability depended on the cell density, suggesting the release of growth and differentiation stimulation substances into culture supernatant. Higher concentrations of SE partially reduced the Aβ1-42 aggregation.

CONCLUSION

Hormetic growth stimulation and inhibition of aggregation may be involved in the neuroprotective activity of SE.

Nitric oxide-heat shock protein axis in menopausal hot flushes: neglected metabolic issues of chronic inflammatory diseases associated with deranged heat shock response

BACKGROUND

Although some unequivocal underlying mechanisms of menopausal hot flushes have been demonstrated in animal models, the paucity of similar approaches in humans impedes further mechanistic outcomes. Human studies might show some as yet unexpected physiological mechanisms of metabolic adaptation that permeate the phase of decreased oestrogen levels in both symptomatic and asymptomatic women. This is particularly relevant because both the severity and time span of hot flushes are associated with increased risk of chronic inflammatory disease. On the other hand, oestrogen induces the expression of heat shock proteins of the 70 kDa family (HSP70), which are anti-inflammatory and cytoprotective protein chaperones, whose expression is modulated by different types of physiologically stressful situations, including heat stress and exercise. Therefore, lower HSP70 expression secondary to oestrogen deficiency increases cardiovascular risk and predisposes the patient to senescence-associated secretory phenotype (SASP) that culminates in chronic inflammatory diseases, such as obesities, type 2 diabetes, neuromuscular and neurodegenerative diseases.

OBJECTIVE AND RATIONALE

This review focuses on HSP70 and its accompanying heat shock response (HSR), which is an anti-inflammatory and antisenescent pathway whose intracellular triggering is also oestrogen-dependent via nitric oxide (NO) production. The main goal of the manuscript was to show that the vasomotor symptoms that accompany hot flushes may be a disguised clue for important neuroendocrine alterations linking oestrogen deficiency to the anti-inflammatory HSR.

SEARCH METHODS

Results from our own group and recent evidence on hypothalamic control of central temperature guided a search on PubMed and Google Scholar websites.

OUTCOMES

Oestrogen elicits rapid production of the vasodilatory gas NO, a powerful activator of HSP70 expression. Whence, part of the protective effects of oestrogen over cardiovascular and neuroendocrine systems is tied to its capacity of inducing the NO-elicited HSR. The hypothalamic areas involved in thermoregulation (infundibular nucleus in humans and arcuate nucleus in other mammals) and whose neurons are known to have their function altered after long-term oestrogen ablation, particularly kisspeptin-neurokinin B-dynorphin neurons, (KNDy) are the same that drive neuroprotective expression of HSP70 and, in many cases, this response is via NO even in the absence of oestrogen. From thence, it is not illogical that hot flushes might be related to an evolutionary adaptation to re-equip the NO-HSP70 axis during the downfall of circulating oestrogen.

WIDER IMPLICATIONS

Understanding of HSR could shed light on yet uncovered mechanisms of menopause-associated diseases as well as on possible manipulation of HSR in menopausal women through physiological, pharmacological, nutraceutical and prebiotic interventions. Moreover, decreased HSR indices (that can be clinically determined with ease) in perimenopause could be of prognostic value in predicting the moment and appropriateness of starting a HRT.

Re-evaluation of Culture Condition of PC12 and SH-SY5Y Cells Based on Growth Rate and Amino Acid Consumption

BACKGROUND/AIM

Most of the previous investigators have used various types of media for the culture of nerve cells. In order to optimize the culture conditions, we compared the growth rate and amino acid consumption by two popular neuron models, rat PC12 and human SH-SY5Y, grown in DMEM or DMEM: Ham's F-12 (1:1): non-essential amino acids, supplemented with 10% fetal bovine serum (referred to DMEM and Mix, respectively).

MATERIALS AND METHODS

Cell growth was monitored by the MTT method. Amino acids in the culture medium were quantitated by amino acid analysis after deproteinization.

RESULTS

Efficient cell attachment could be achieved even if PC12 cells were inoculated at extreme lower cell density in a non-coated plain dish, without addition of its condition medium. Both PC12 and SH-SY5Y cells proliferated up to slightly higher cell density in DMEM than in Mix. Approximately 2-fold higher utilization rate of glutamine and essential amino acids was observed in DMEM. Amyloid peptides such as Aβ_1-42 and Aβ_25-35 suppressed their growth nearly by 50%.

CONCLUSION

The present study suggests the usefulness of DMEM for the study of searching neuroprotective substances, based on its favorable effects on cell attachment, cell growth and amino acid utilization as well as amyloid peptide sensitivity.

The new kisspeptin derivative - kissorphin (KSO) - attenuates acute hyperlocomotion and sensitization induced by ethanol and morphine in mice

Kissorphin (KSO) is a new peptide derived from kisspeptin-10. This peptide possesses neuropeptide FF (NPFF)-like biological activity in vitro; NPFF, in many cases, inhibits opioid and ethanol effects in rodents. Therefore, the current study explored the influence of KSO on acute ethanol- and morphine-induced hyperactivity, and on the development and expression of locomotor sensitization induced by these drugs. In the present study, sensitization to locomotor effects was induced by repeated exposure to ethanol (2.4 g/kg, intraperitoneally [i.p.], 1 × 4 days) or morphine (10 mg/kg, subcutaneously [s.c.], 1 × 7 days). We found that KSO (1-10 nmol/300 μL, intravenously [i.v.]) did not have an impact on locomotor activity of naïve mice. However, it reduced both acute ethanol- (10 nmol/300 μL) and morphine-induced hyperactivity (3 and 10 nmol/300 μL). Pretreatment of animals with KSO (10 nmol/300 μL), before every ethanol or morphine injection during development of sensitization or before the ethanol or morphine challenge, attenuated the development, as well as the expression of locomotor sensitization to both substances. Moreover, prior administration of the NPFF receptor antagonist RF9 (10 nmol/300 μL, i.v.) inhibited the ability of KSO (10 nmol/300 μL) to reduce the expression of ethanol and morphine sensitization. KSO given alone, at all used doses, did not influence the motor coordination measured via the rotarod test. The results from this study show that KSO effectively attenuated acute and repeated effects of ethanol and morphine. Thus, KSO possesses NPFF-like anti-opioid activity in these behavioral studies.

NEUROPROTECTIVE EFFECT OF AMORPHOPHALLUS CAMPANULATUS IN STZ INDUCED ALZHEIMER RAT MODEL

Background:

The present investigation deals with the assessment of neuroprotective effect Amorphophallus campanulatus (AC) tuber in alzheimer diseased (AD) rat and also postulates its possible mechanism of action.

Material and Methods:

AD was induced by administering streptozotocin i.e. STZ (3 mg/kg, ICV) day one and 3^rd day after surgery. Surgery was performed on anesthetized rats by the help of stereotaxic apparatus. STZ induced AD rats were treated with petroleum ether extract of AC (100, 200 and 500 mg/kg, p.o.) for 14 days. Effect of AC tuber in AD rats were assessed by estimating the alteration in the behavior (Y maze apparatus and single trail passive avoidance), biochemical parameter in the brain tissue {Oxidative stress parameters (SOD, CAT and LPO), amyloid β peptide (Aβ) and acetylcholinesterase (AchE)} and histopathological study of brain tissue.

Result:

Treatment with AC shows significant (p<0.01) increased in the % of alteration in the behavior and step through latency in Y maze task and single trial passive avoidance test compared to AD rats. AC significantly (p<0.01) decreases the Aβ1-40, Aβ1-42 peptides and AchE in the brain tissue compared to AD rats. Whereas, treatment with AC significantly reduces the oxidative stress level in AD rats. Histopathological study reveals that treatment with AC extract reduces the amyloid plaque formation in the brain tissue of AD rat.

Conclusion:

The present study concludes the neuroprotective effect of AC extract in AD rats by reducing oxidative stress, Aβ and AchE in the brain tissue.

Endogenous opiates and behavior: 2013

This paper is the thirty-sixth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2013 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia; stress and social status; tolerance and dependence; learning and memory; eating and drinking; alcohol and drugs of abuse; sexual activity and hormones, pregnancy, development and endocrinology; mental illness and mood; seizures and neurologic disorders; electrical-related activity and neurophysiology; general activity and locomotion; gastrointestinal, renal and hepatic functions; cardiovascular responses; respiration and thermoregulation; and immunological responses.

Immunocytochemical staining of endogenous nuclear proteins with the HIS-1 anti-poly-histidine monoclonal antibody: a potential source of error in His-tagged protein detection

Histidine-tagged proteins are widely used in biochemical studies and frequently detected with antibodies specific for the histidine tag. Immunocytochemistry is widely used in studies with overexpressed proteins to determine cellular localization and in the case of histidine-tagged proteins can be carried out with anti-polyhistidine antibodies. Recent studies have suggested that polyhistidine sequences are present within a small number of human proteins and may direct expression to the nucleus and nuclear speckles compartments of the cell. In this study immunocytochemical staining of human SH-SY5Y neuroblastoma cell lines with the HIS-1 anti-polyhistidine monoclonal antibody were determined. Results showed that the HIS-1 anti-polyhistidine monoclonal antibody stained endogenous nuclear proteins in SH-SY5Y cells. The stained proteins were contained within the nuclear membrane, but were not directly linked to DNA. In a histidine-tagged catalase overexpressing cell line the HIS-1 anti-polyhistidine monoclonal antibody showed nuclear staining, whilst staining with the CAT-505 anti-catalase monoclonal antibody showed primarily cytoplasmic staining. These results suggest that anti-polyhistidine antibody staining shows significant cross-reactivity with endogenous nuclear proteins in SH-SY5Y neuroblastoma cells and may not be suitable for localization studies of histidine-tagged proteins. Immunocytochemical studies with anti-polyhistidine antibodies and localization of histidine-tagged proteins must be confirmed with protein specific antibodies or other methodology.

Benzothiazole aniline tetra(ethylene glycol) and 3-amino-1,2,4-triazole inhibit neuroprotection against amyloid peptides by catalase overexpression in vitro

Alzheimer's disease, Familial British dementia, Familial Danish dementia, Type 2 diabetes mellitus, plus Creutzfeldt-Jakob disease are associated with amyloid fibril deposition and oxidative stress. The antioxidant enzyme catalase is a neuroprotective amyloid binding protein. Herein the effects of catalase overexpression in SH-SY5Y neuronal cells on the toxicity of amyloid-β (Aβ), amyloid-Bri (ABri), amyloid-Dan (ADan), amylin (IAPP), and prion protein (PrP) peptides were determined. Results showed catalase overexpression was neuroprotective against Aβ, ABri, ADan, IAPP, and PrP peptides. The catalase inhibitor 3-amino-1,2,4-triazole (3-AT) and catalase-amyloid interaction inhibitor benzothiazole aniline tetra(ethylene glycol) (BTA-EG4) significantly enhanced neurotoxicity of amyloid peptides in catalase overexpressing neuronal cells. This suggests catalase neuroprotection involves breakdown of hydrogen peroxide (H2O2) plus a direct binding interaction between catalase and the Aβ, ABri, ADan, IAPP, and PrP peptides. Kisspeptin 45-50 had additive neuroprotective actions against the Aβ peptide in catalase overexpressing cells. The effects of 3-AT had an intracellular site of action, while catalase-amyloid interactions had an extracellular component. These results suggest that the 3-AT and BTA-EG4 compounds may be able to inhibit endogenous catalase mediated neuroprotection. Use of BTA-EG4, or compounds that inhibit catalase binding to amyloid peptides, as potential therapeutics for Neurodegenerative diseases may therefore result in unwanted effects.