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Featured Article: Cholinergic immunolesioning produced tangle-like inclusions in TgCRND8 brain
Chauhan N (2007) Featured Article: Cholinergic immunolesioning produced tangle-like inclusions in TgCRND8 brain. Targeting Trends 8(1)
Related Products: mu p75-SAP (Cat. #IT-16)
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Effect of running on neurogenesis in cholinergic lesioned mice
Ho N, Han S, Dawe GS (2006) Effect of running on neurogenesis in cholinergic lesioned mice. Neuroscience 2006 Abstracts 318.5. Society for Neuroscience, Atlanta, GA.
Summary: Neurogenesis occurs mainly in two regions of the adult rodent brain, the dentate gyrus of the hippocampus and the subventricular zone. There are many factors which regulate neurogenesis, but voluntary exercise has consistently been shown to enhance neurogenesis. Exercise has been reported to specifically stimulate neural cell proliferation in the hippocampus but not the olfactory bulb. One of the major sources of afferents to the hippocampus are the septohippocampal projections, in which axons from the medial septum and diagonal band of Broca (MSDB) project to the hippocampus. Major components of the septohippocampal pathway that act as ‘pacemakers’ for hippocampal theta rhythm, which increases in conjunction with the voluntary running, are the cholinergic and GABAergic projections rising from cells in the MSDB. This present study investigates the effect of a partial cholinergic lesion in the basal forebrain and MSDB of mice, a partial model of the neurodegeneration that occurs in Alzheimer’s disease, on neural cell proliferation and neurogenesis. Murine p75-SAP, a conjugate of a p75 antibody that targets selectively cholinergic cells and cytotoxic saporin, was injected into the ventricles of female adult Swiss mice. After recovery from surgery mice were then administered bromodeoxyuridine (BrdU). BrdU immunopositive cells were quantified 24 hours and 4 weeks to assess for neural cell proliferation and survival of newly generated cells. Partial cholinergic denervation led to a decrease in the survival of new born cells in the dentate gyrus. We compared the effects of voluntary running for a period of 12 days in non-lesioned and lesioned mice under similar experimental conditions. Running resulted in an increase in neural cell proliferation for both the non-lesioned and lesioned groups. Running led to a marked increase in cell proliferation in lesioned mice compared to the controls, and also enhanced neurogenesis, as determined by the colocalization of BrdU and the neuronal nuclei marker NeuN in cells within the dentate gyrus. The present study suggests that voluntary running may have a positive effect on neurogenesis in neurodegenerative models in rodents. Further work needs to be done to elucidate the underlying mechanisms of exercise-induced neurogenesis.
Related Products: mu p75-SAP (Cat. #IT-16)
Cholinergic immunolesioning produced tangle-like inclusions in TgCRND8 brain
Chauhan NB (2006) Cholinergic immunolesioning produced tangle-like inclusions in TgCRND8 brain. Neuroscience 2006 Abstracts 271.8. Society for Neuroscience, Atlanta, GA.
Summary: Today’s Alzheimer’s disease (AD) research lacks a “complete” model that would represent both plaque and tangle pathology together with correlative memory deficits. Although currently developed transgenic model including APP/PS1/tau mutations do not “truly” represent AD because tangles observed in AD brain are independent of tau mutations. Subtly increased β-amyloid (Aβ) levels either due to familial mutations or sporadic causes, primarily targets pre-tangle cytopathology and degeneration of basal forebrain cholinergic neurons (BFCN) via deranged signaling of glygogen synthase kinase 3-beta (GSK3β)-, protein kinase A (PKA)-, and extracellular signal-regulated kinase (ERK2) of ERK-mitogen-activated protein kinase (MAPK) cascade, leading to reduced phosphorylation of cAMP responsive element binding protein (CREB) that results in synaptic and memory deficits much earlier than the emergence of classic AD-pathology. Thus, subtly elevated Aβ, together with BFCN deficits resulting from Aβ-induced deranged signaling, set up a vicious feedback loop to produce characteristic plaque- and tangle-pathology observed in AD. Based on these facts, we wished to test if selective lesioning of basal fore brain cholinergic neurons during the early stages of amyloid build-up will exacerbate tau phosphorylation and produce tangle-like inclusions in transgenic mice with APP mutations. We produced selective immunotoxic lesions of BFCN by injecting the BFCN-specific cholinergic immunotoxin, which is known to specifically target p75-expressing BFCN and spare p75-expressing cerebellar neurons (Mu-p75-Saporin, Advanced Targeting Systems, #IT-16), intracerebroventricularly (ICV) in TgCRND8 mice harboring Swedish (KM670/671NL) and Indiana (V717F) mutations. This model exhibited tangle-like inclusions, provoked already existing plaque pathology, and worsened already impaired behavioral deficits.
Related Products: mu p75-SAP (Cat. #IT-16)
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Selective cholinergic immunolesioning in alpha7 nAChR KO mice: Anatomical, neurochemical and functional effects
Ledri M, Cusulin C, Novati A, Aztiria E, Leanza G (2006) Selective cholinergic immunolesioning in alpha7 nAChR KO mice: Anatomical, neurochemical and functional effects. FENS 2006 Abstracts 3:A1610.10. Federation of European Neuroscience Societies, Vienna, Austria.
Related Products: mu p75-SAP (Cat. #IT-16)
Immunolesion of p75 NGF receptor in the mouse SCN attenuated light-induced phase shift of the circadian wheel-running rhythm
Vijayakumar S, Masood A, Smith M, Clark JP, Nelson DE, Ding JM (2005) Immunolesion of p75 NGF receptor in the mouse SCN attenuated light-induced phase shift of the circadian wheel-running rhythm. Neuroscience 2005 Abstracts 766.18. Society for Neuroscience, Washington, DC.
Summary: Mammalian circadian rhythms are regulated by the suprachiasmatic nucleus (SCN) of the hypothalamus. Alhough the SCN can orchestrate these rhythms in the absence of external cues, it is entrained to environmental cycles through the retinohypothalamic tract. Light-induced phase shifts in circadian rhythm is a classic example of short-term environmental stimuli inducing lasting changes in intracellular signals and gene expression within the SCN cells that alter the phase of the SCN pacemaker and allow entraiment. Since neurotrophins are known to mediate neural plasticity, we investigated the role of brain-derived neurotrophic factor (BDNF) on resetting the phase of the SCN both in vitro and in vivo. We used the SCN brain slice model to study the direct effect of BDNF on the circadian rhythm. Briefly, coronal hypothalamic slices containing the SCN were prepared using 129B/6 mice. The circadian rhythm of the SCN neurons in the brain slice was monitored for 2-3 days by continuously sampling the spike frequencies with single-unit extracellular electrodes. Brief microdrop applications of BDNF (10 uM) induced robust phase delays at CT 16 and phase advances at CT 22. BDNF binds to neurotrophin receptors, including the low affinity p75NTR, which is localized in the SCN. When the toxin Saporin is conjugated to the antibody against p75NTR, it selectively destroys the cells expressing the p75NTR. Three weeks after the stereotaxic injection of the mu p75-Saporin (Advanced Targeting System) into the third ventricle (1 ul over 20 min), the p75NTR immunoreactivity in the mouse SCN is abolished. Immunolesion of the p75NTR in the SCN attenuated light-induced phase delays of the wheel running rhythm at CT16. Consistent with previous findings, our results support a role for BDNF and its receptor p75NTR, in resetting the circadian rhythm of the SCN in mice.
Related Products: mu p75-SAP (Cat. #IT-16)
Minocycline protects basal forebrain cholinergic neurons from mu p75-saporin immunotoxic lesioning.
Hunter CL, Quintero EM, Gilstrap L, Bhat NR, Granholm AC (2004) Minocycline protects basal forebrain cholinergic neurons from mu p75-saporin immunotoxic lesioning. Eur J Neurosci 19(12):3305-3316. doi: 10.1111/j.0953-816X.2004.03439.x
Summary: In Alzheimer’s disease basal cholinergic degeneration is accompanied by glial activation and the release of pro-inflammatory cytokines. To investigate whether neural events other than degeneration can cause effects of Alzheimer’s disease, the authors treated mice with minocycline after lesioning the basal forebrain with 3.6 µg of mu p75-SAP (Cat. #IT-16). Administration of minocycline reduced the loss of cholinergic neurons, reduced glial response to the lesion, and lessened the cognitive impairment due to mu p75-SAP lesions.
Related Products: mu p75-SAP (Cat. #IT-16)
The effects of ethanol and cholinergic lesions on anxiety in mice
Hummer TA, Johnson AD, Givens B (2003) The effects of ethanol and cholinergic lesions on anxiety in mice. Neuroscience 2003 Abstracts 859.16. Society for Neuroscience, New Orleans, LA.
Summary: Ethanol’s anxiolytic properties in mice are well-documented as measured with an elevated plus-maze. The effect of IP ethanol injections and cholinergic lesions on anxiety was investigated. Animals were injected with 0.5 µg of the cholinergic immunotoxin anti-murine-p75-saporin or control saline into the right lateral ventricle. After recovery (14-17 d), mice were given an IP 1.6 g/kg ethanol (10% v/v) or vehicle injection. After 60 min, animals were placed on the elevated plus-maze for a 10 min session and then perfused. Mice displayed increased open arm entries and time following ethanol. Saporin did not effect measures of anxiety nor interact with the effects of ethanol. Choline acetyltransferase staining was performed to confirm the extent of the cholinergic lesioning, and ethanol assays confirmed the presence or absence of ethanol in the blood stream. The research demonstrates that, as measured in the plus-maze, the basal forebrain cholinergic system has no significant involvement in anxiety nor in ethanol’s anxiolytic effects.
Related Products: mu p75-SAP (Cat. #IT-16)
Neuroinflammatory response to mu p75-saporin immunotoxin-induced degeneration of basal forebrain cholinergic neurons
Hunter CL, Quintero EM, Gilstrap L, Bhat NR, Granholm AE (2003) Neuroinflammatory response to mu p75-saporin immunotoxin-induced degeneration of basal forebrain cholinergic neurons. Neuroscience 2003 Abstracts 527.15. Society for Neuroscience, New Orleans, LA.
Summary: Basal forebrain cholinergic neurons, which provide the major cholinergic innervation to the cortical regions and play a key role in the processing of information involved in cognitive processes, degenerate during both normal aging and Alzheimer’s disease. Neuroinflammation, specifically the activation of microglia, is known to affect the progression of neuronal degeneration. Activated microglia produce inflammatory mediators that have neuropathic as well as neuroprotective actions, and it has been suggested that inflammatory mediators produced by activated microglia may play a role in the decline of specific neuronal sub-types in neurodegenerative diseases. The immunotoxin mu p75-SAP has been shown to selectively destroy cholinergic neurons in the basal forebrain of mice, resulting in reduced choline acetyl-transferase activity and cognitive impairments. To characterize the inflammatory response to mu p75-SAP lesions, 3 month-old mice received icv injections of mu p75-SAP (3.6 mg) followed by treatment with an anti-inflammatory agent, minocycline (45 mg/kg i.p.), or saline. Seven days after lesioning, immunohistochemistry was used to analyze markers for cholinergic and non-cholinergic neurons and inflammation. Cholinergic lesioning resulted in a dramatic increase in CD45, a microglial marker, but no change in GFAP, an astroglial marker, in the basal forebrain region. Lesioned animals had elevated levels of phosphorylated p38, a MAP kinase protein involved in inflammatory pathways. Minocycline treatment reduced this inflammatory response. Furthermore, preliminary results suggest that animals treated with minocycline after mu p75-SAP lesioning are partially protected from cholinergic degeneration.
Related Products: mu p75-SAP (Cat. #IT-16)
The efficacy of intraparenchymal anti-p75 immunotoxin on medial septal cholinergic neurons in mice
Schaevitz LR, Baxter MG, Stearns NA, Huang YY, Lappi DA, Berger-Sweeney J (2002) The efficacy of intraparenchymal anti-p75 immunotoxin on medial septal cholinergic neurons in mice. Neuroscience 2002 Abstracts 778.11. Society for Neuroscience, Orlando, FL.
Summary: We have shown previously that anti-murine-p75-SAP (saporin conjugated to a rat monoclonal antibody against the mouse p75 nerve growth factor receptor) selectively destroys basal forebrain cholinergic neurons in vivo after intracerebroventricular injections (J. Neurosci. 21:8164-73). Cholinergic neuronal loss was more extensive in the medial septum (MS) than the nucleus basalis magnocellularis; it is unclear whether this distinction is due to toxin diffusion from the ventricles or differential sensitivity of the neuronal populations. Intraparenchymal (IPC) injections to specific targets can help resolve the issue. Here, we examine the efficacy of anti-murine-p75-SAP IPC injections on cholinergic neurons. Saline or different doses of toxin (0.1, 0.2, 0.4, 0.9, 4.7, and 9.4 microg/microL) were injected into the MS of adult male C57BL/6J mice. Ten days post lesion, brain sections were stained for choline acetyltransferase and p75 (cholinergic markers) to determine toxin efficacy, and calbindin and parvalbumin (non-cholinergic markers) to determine toxin specificity. Toxin doses below 1.0 microg/microL had no effect on cholinergic or non-cholinergic neurons, while doses above 4.7 microg/microL resulted in the complete destruction of both cholinergic and non-cholinergic neurons. More thorough testing of doses between 1 and 4 microg/microL will be required to determine the optimal toxin dose for IPC injections.
Related Products: mu p75-SAP (Cat. #IT-16)
Selective immunolesions of cholinergic neurons in mice: effects on neuroanatomy, neurochemistry, and behavior.
Berger-Sweeney JE, Stearns NA, Murg SL, Floerke-Nashner LR, Lappi DA, Baxter MG (2001) Selective immunolesions of cholinergic neurons in mice: effects on neuroanatomy, neurochemistry, and behavior. J Neurosci 21(20):8164-8173. doi: 10.1523/JNEUROSCI.21-20-08164.2001
Summary: 192-Saporin (Cat. #IT-01) has long been an effective agent for elimination of cholinergic neurons in the basal forebrain of rats. Until the development of mu p75-SAP (Cat. #IT-16) there was no equivalent agent for use in mice. The authors tested mu p75-SAP in vitro and in vivo (1.8-3.6 µg in right lateral ventricle), using cytotoxic, histochemical, and behavioral assays. The data shows that mu p75-SAP is a highly selective and efficacious lesioning agent for cholinergic neurons in the mouse. The authors conclude that mu p75-SAP will be a powerful tool to use in combination with genetic modification to investigate cholinergic damage in mouse models of Alzheimer’s disease.
Related Products: mu p75-SAP (Cat. #IT-16), 192-IgG-SAP (Cat. #IT-01)