alzheimers-disease

Blumenthal SA, Maness EBL, Fadel JR, Burk JA (2019) Effects of an orexin-2 receptor agonist on attention in rats following loss of cortical cholinergic projections. Neuroscience 2019 Abstracts 418.06. Society for Neuroscience, Chicago, IL.

Summary: Deterioration to the basal forebrain cholinergic system (BFCS) is linked to age-related cognitive impairment, specifically to the pathology of Alzheimer’s disease (AD). Animals with BFCS damage perform poorly on learning, memory, and attention tasks, indicating cognitive deficits. The orexin neuropeptide system, comprised of two neuropeptides (orexin A and orexin B), has also been implicated in the cognitive decline associated with aging, likely due to the role of orexins in promoting attention. Two orexin receptor subtypes exist, orexin 1 (Ox1R) and orexin 2 (Ox2R). Studies have examined the effects of stimulation and blockage of both receptors together and Ox1R alone on attention; but no studies have examined the role of Ox2Rs in attention through the use of Ox2R agonists. Ox2Rs may be implicated in attentional processes and the loss of orexin neurons seen in age-related cognitive decline. In order to examine the role of Ox2Rs in attention following BFCS deterioration, the present study administered the Ox2R agonist, YNT-185, to rats given intrabasalis infusions of either saline (n = 12) or 192 IgG saporin (n=11), an immunotoxin which selectively destroys the BFCS. Animals received infusions of YNT-185 to the lateral ventricle (LV) in doses of 0, 1, 10, and 100nM across four separate sessions and performance was then assessed on a sustained attention task requiring discrimination between signal and non-signal trials through lever presses. The 100nM dose of YNT-185 improved attentional performance, as compared to the 0nM dose, for rats given the immunotoxin, but worsened performance for rats given saline lesions. YNT-185 may be efficacious in aiding attentional function in animals with vulnerable cholinergic systems but may lead to overexcitation for those with intact cholinergic function.

Related Products: 192-IgG-SAP (Cat. #IT-01)

Cunningham C, Lowry JP (2019) In vivo monitoring of cholinergic neurotransmission with a microelectrochemical choline biosensor. Neuroscience 2019 Abstracts 614.03. Society for Neuroscience, Chicago, IL.

Summary: Acetylcholine acts as a key neuromodulator within the central nervous system, capable of altering neuronal excitability and coordinating neuronal firing patterns. Conversely, cholinergic neurotransmission plays a crucial role in a variety of cognitive functions, including the encoding of new memories. Cholinergic neuronal loss, and the resulting drop in cholinergic neurotransmission (collectively referred to as hypocholinergia), is closely associated with cognitive dysfunction in a number of chronic neurodegenerative disorders including Alzheimer’s disease. However, conventional analytical techniques for monitoring in vivo cholinergic neurotransmission lack the spatiotemporal resolution required to accurately detect endogenous cholinergic dynamics. Here we validate in mice a Pt-based electrochemical biosensor for selective monitoring of choline, a verified marker of cholinergic transmission. Enzymatic choline biosensors (modified with choline oxidase) were sterotaxically implanted in the medial prefrontal cortex (mPFC) and contralateral dorsal hippocampus (dHPC) of female C57Bl6J mice. Real-time choline current recordings over a period of several days revealed circadian fluctuations in both regions, with extracellular choline levels highest during light phases. Administration of pharmacological compounds known to induce central acetylcholine release, scopolamine (1mg/kg) and amphetamine (4mg/kg), evoked a robust increase in choline current. In contrast, peripheral injection of the reversible acetylcholinesterase inhibitor, donepezil (3mg/kg), produced a marked decrease in recorded choline current. The induction of systemic infammation with bacterial lipopolysaccharide (LPS; 500µg/kg) produced characteristic ‘sickness behaviour’ in mice and evoked a tonic rise in central choline levels in both the mPFC and dHPC. Furthermore, the induction of hypocholinergia in selected mice was preformed via intracerebroventricular injections of murine-p75-saporin immunotoxin (1.2µg). Evoked cholinergic neurotransmission was dramatically attenuated in lesioned (hypocholinergic) mice. Collectively, the data suggests that microelectrochemical choline biosensors may serve as a powerful tool for monitoring cholinergic neurotransmission across a number of behavioural and disease states.

Related Products: mu p75-SAP (Cat. #IT-16)

Verkhratsky A, Parpura V, Rodriguez-Arellano J, Zorec R (2019) Astroglia in Alzheimer’s Disease. (eds. Verkhratsky A, Ho M, Zorec R, Parpura V). In: Advances in Experimental Medicine and Biology: Neuroglia in Neurodegenerative Diseases. 1175:273-324. Springer, Singapore. doi: 10.1007/978-981-13-9913-8_11

Summary: A review of the tools for creating animal models of Alzheimer’s Disease. 192-IgG-SAP binds selectively and irreversibly to low-affinity nerve growth factor receptor interrupting cholinergic neuronal protein synthesis was employed. Anti-DBH-SAP binds dopamine-β-hydroxylase, which is not only localized mainly in the cytosol, but also at the plasma membrane surface of noradrenergic neurons. Anti-DBH-SAP produced specific and dose-dependent depletions of locus coeruleus neurons, with no effects on other cholinergic, dopaminergic or serotonergic neuronal populations. The possibility to induce a partial or total noradrenergic loss (by varying the injected dose) makes this immunotoxic approach an ideal model to study events within the noradrenergic projection system, as they occur during age-related demise of locus coeruleus in humans.

Related Products: 192-IgG-SAP (Cat. #IT-01), Anti-DBH-SAP (Cat. #IT-03)

Veening-Griffioen DH, Ferreira GS, van Meer PJK, Boon WPC, Gispen-de Wied CC, Moors EHM, Schellekens H (2019) Are some animal models more equal than others? A case study on the translational value of animal models of efficacy for Alzheimer’s disease. Eur J Pharmacol 859:172524. doi: 10.1016/j.ejphar.2019.172524 PMID: 31291566

Related Products: 192-IgG-SAP (Cat. #IT-01)

Nizari S, Carare RO, Romero IA, Hawkes CA (2019) 3D reconstruction of the neurovascular unit reveals differential loss of cholinergic innervation in the cortex and hippocampus of the adult mouse brain. Front Aging Neurosci 11:172. doi: 10.3389/fnagi.2019.00172

Objective: To further characterize the effect of the loss of cholinergic innervation on the NVU (neurovascular unit) in Alzheimer’s Disease.

Summary: Significantly less ChAT staining was detected in the medial septum of saporin-treated mice at 45 days post-surgery. This was accompanied by a significant decrease in cholinergic nerve fiber density in the hippocampus and the cortex. As expected, p75 NTR-negative neurons in the striatum were not affected by mu p75-SAP treatment.

Usage: In this study, the mu-p75-SAP was used to induce death of basal forebrain cholinergic neurons and their fiber projections. mu p75-SAP 0.5 µL (0.596 µg/µL) or 0.9% saline (n = 19) was injected into each ventricle.

Related Products: mu p75-SAP (Cat. #IT-16)

Moreno-Rodriguez M, Martinez-Gardeazabal J, Llorente-Ovejero A, Lombardero L, Manuel I, Rodriguez-Puertas R (2018) Learning and memory improvement mediated by CB1 cannabinoid receptors in animal models of cholinergic dysfunction. Neuroscience 2018 Abstracts 049.05 / S3. Society for Neuroscience, San Diego, CA.

Summary: The selective vulnerability of the basal forebrain cholinergic system (BFCS) is responsible for most of the clinical alterations in learning and memory processes that are characteristic of the Alzheimer’s disease (AD). The loss of cholinergic neurons and muscarinic receptors (MR) in the nucleus basalis of Meynert have been reported in AD. The endocannabinoid system is a neuromodulator of the BFCS, but there are controversial reports regarding the cannabinoid effects in learning and memory processes. The animal models of cholinergic impairment mimic the main histopathological and behavioral effects observed in patients. The MR antagonism, e.g. using scopolamine (SCOP), is used as a model of amnesia in rodents. The intraparenchymal administration of 192-IgG-saporin (SAP) in the nucleus basalis magnocellularis eliminates cholinergic neurons leading to learning and memory deficits. Then, the present study evaluates the modulation of spatial and working memory with the Barnes Maze following a subchronic treatment with a low dose (0.5 mg/kg) of WIN55,212-2 (WIN) in both the SCOP and SAP models of learning and memory deficit. In the SCOP model, the administration of WIN protects learning and memory impairment during the probe trial, recorded as the time spent in the target quadrant (WIN + SCOP: 78 ± 13 sec vs VEH + SCOP: 45 ± 3 sec; p < 0.001). A similar effect of the treatment was observed in the SAP model (SAP: 50 ± 3 sec vs SAP + WIN: 82 ± 7 sec; p < 0.001). This effect was specifically mediated by CB1 receptors, since it was blocked by the co-administration of the specific CB1 antagonist, SR141716A (0.5 mg/kg) (SAP: 49 ± 3 sec vs SAP + WIN + SR: 48 ± 5 sec). However, higher doses of WIN (3 mg/kg) induced negative effects in learning and memory in control (C) rats, but positive and comparable to the lower dose in the SAP model (C: 89 ± 3 sec, C + WIN-3 mg/kg: 48 ± 3 sec; SAP: 49 ± 3; SAP + WIN-3 mg/kg: 80 ± 12 sec; p < 0.001). The CB1 receptor activation by low doses of the cannabinoid agonist WIN are able to block the amnesic effects induced by SCOP and also the learning and memory impairment produced by the BFCS pathway degeneration. CB1 agonists could contribute to improve the clinical symptoms of AD. International application patent PCT/EP2018/054525.

Related Products: 192-IgG-SAP (Cat. #IT-01)

Kong C, Shin J, Lee J, Koh C, Sim J, Na Y, Chang W, Chang J (2018) Improvements of cognitive function by focused ultrasound associated with adult hippocampal neurogenesis in immunotoxin 192-Saporin rat model of cholinergic degeneration. Neuroscience 2018 Abstracts 174.27 / JJJ31. Society for Neuroscience, San Diego, CA.

Summary: Introduction: Alzheimer’s disease is irreversible, progressive neurodegenerative disorder that destroys memory and cognitive function. Recently, focused ultrasound (FUS) has been demonstrated that FUS-mediated BBB opening induces an increase in hippocampal neurogenesis in adult rodents. In this study, we investigated the effects of FUS on memory and cognitive function after 192 IgG-saporin lesion. Materials and Methods: The present study utilized adult male Sprague-Dawley rats (200-250 g). Animals were divided into the three groups: Sham group (PBS injection), Lesion group (saporin injection), FUS group (saporin + FUS treatment). Lesion groups were injected bilaterally into the lateral ventricle. Rats were sonicated using a single-element transducer with microbubble. The acoustic parameters used for each sonication are: pressure amplitude 0.3 MPa, pulse length 10 ms, burst repetition frequency 1 Hz, and a duration of 120 s. BrdU was intraperitoneally injected two times per day for 4 consecutive days starting 24 hours after sonication. Two weeks after IgG-saporin administration, spatial memory was tested with the Morris water maze training. Results: In the water maze test, the FUS groups were significantly increased in number of crossing and platform zone, compared to the lesion group. We confirmed that the number of BrdU+, DCX+, and NeuN+ were significantly increased in the dentate gyrus following FUS sonication, compared to the lesion groups. Also, we found that the expression level of BDNF and TrkB increased in FUS group. Conclusion: Our results suggest that FUS treatments led to spatial memory improvement in cholinergic deficits rat model. Therefore, this provides evidence that the behavior changes may be mediated by increased acetylcholine activity and neuronal plasticity. Furthermore, FUS may represent a promising treatment for neurodegenerative disease, including Alzheimer’s disease because neurogenesis is associated with memory and cognitive function.

Related Products: 192-IgG-SAP (Cat. #IT-01)

Qian L, Milne MR, Shepheard S, Rogers ML, Medeiros R, Coulson EJ (2019) Removal of p75 neurotrophin receptor expression from cholinergic basal forebrain neurons reduces amyloid-β plaque deposition and cognitive impairment in aged APP/PS1 mice. Mol Neurobiol 56(7):4639-4652. doi: 10.1007/s12035-018-1404-2

Objective: To investigate the contribution of CBF neuronal p75NTR to the progression of Alzheimer’s Disease

Summary: Data indicate that a direct interaction between CBF-expressed p75NTR and Aβ does not contribute significantly to the regulation of Aβ load.

Usage: To lesion CBF neurons, a single infusion of mu p75-SAP or control Rabbit IgG-SAP (0.4 mg/ml) was stereotaxically-injected into the basal forebrain.

Related Products: mu p75-SAP (Cat. #IT-16), Rabbit IgG-SAP (Cat. #IT-35)

Pitake S, Ralph PC, DeBrecht J, Mishra SK (2018) Atopic dermatitis linked cytokine interleukin-31 induced itch mediated via a neuropeptide natriuretic polypeptide b. Acta Derm Venereol 98:795-796. doi: 10.2340/00015555-2977

Objective: To determine if NPPB is involved as a neuropeptide in IL-31-mediated itch in atopic dermatitis (AD) via natriuretic polypeptide receptor A (NPRA) in the spinal cord.

Summary: This study reveals an important role of neuropeptide NPPB in AD that could provide a therapeutic target for alleviating chronic itch associated with AD.

Usage: To further demonstrate the IL-31-mediated itch response by NPRA receptors expressed in the spinal cord, Nppb-SAP (5 μg) was used to eliminate neurons expressing NPRA receptors in the spinal cord.

Related Products: Nppb-SAP (Cat. #IT-69)

Leanza G, Gulino R, Zorec R (2018) Noradrenergic hypothesis linking neurodegeneration-based cognitive decline and astroglia. Front Mol Neurosci 11:254. doi: 10.3389/fnmol.2018.00254

Objective: To examine noradrenergic dysfunction in AD-related cognitive decline in humans and its potential involvement in AD pathology and disease progression.

Summary: The authors discuss noradrenergic dysfunction in AD-related cognitive decline. The research focuses on animal models to allow the validation of the noradrenergic hypothesis of AD, including those based upon the Anti-DBH-SAP-mediated ablation of LC. The article also addresses how astrocytes may participate in the regulation of neurogenesis, a new strategy for preventing LC neuron loss.

Usage: DBH (–/–) knockout mice do not seem to offer the possibility to obtain partial or graded neurotransmitter depletions. In light of these limitations, the authors used Anti-DBH-SAP which is able to target noradrenergic neurons in the LC with unprecedented selectivity and efficiency. Anti-DBH-SAP was injected bilaterally into the LC.

Related Products: Anti-DBH-SAP (Cat. #IT-03)