targeted-toxins

Cho J, Lee J, Jeong D, Kim H, Chang W, Moon J, Chang J (2016) Placenta-derived mesenchymal stem cells facilitate neural and cognitive recovery in dementia rat model. Neuroscience 2016 Abstracts 38.10 / G29. Society for Neuroscience, San Diego, CA.

Summary: Introduction: Dementia is a term that encompasses various types of neurodegenerative diseases of the brain that cause a gradual decline in mental abilities. Loss of cholinergic neurons in the brain cholinergic system including the hippocampus is a hallmark of many dementia cases. In this study, we report the therapeutic effects of administration of human placenta-derived mesenchymal stem cells (pMSCs) in dementia model Sprague-Dawley (SD) rats using two different cell injection methods: intracerebroventricular (ICV) and intravenous (IV) injections. Methods: Dementia modeling was carried out by intraventricular injection of 192 IgG saporin, which causes lesion of cholinergic neurons. Fifty male SD rats were divided into four groups: normal (n=9), lesion (n=9), ICV (n=12) and IV (n=12). All rats were then subject to Morris water maze test and subsequent immunostaining analyses using markers for human cytoplasm, acetylcholinesterase (AChE), choline acetyltransferase (ChAT) and microglial cells at the hippocampus. Results: Lesioned rats showed poor performance in the Morris water maze test compared to the normal rats. Both ICV and IV pMSC administration allowed significant cognitive recovery compared to the lesioned rats. AChE was also significantly recovered back to normal levels at the hippocampus in rats injected with pMSCs post-lesion. ChAT did not co-localize with pMSCs, showing that pMSCs did not directly differentiate into cholinergic cells. Stem cell count showed a significantly greater number of pMSCs at the hippocampal dentate gyrus in IV group rats compared to ICV group rats. Number of microglial cells increased in lesioned rats, and was significantly reduced back to normal levels after pMSC injection. Discussion: Our results demonstrate that injection of pMSCs facilitates recovery of cholinergic neuronal population and function, as well as cognitive behavior. The mechanism through which such recovery happens does not seem to be direct differentiation of injected pMSCs into cholinergic neurons, but rather seems to be through paracrine effects that resemble microglial function. Further research will be necessary for elucidation of the exact mechanisms involved and establishment of optimal parameters for successful cell homing. Acknowledgements: This study was supported by the grant from the Yonsei University Future-leading Research Initiative (Yonsei Challenge) of 2015 (2015-22-0137) and Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning (2015R1C1A1A02036851).

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

Urquhart M, Reyes BAS, Thomas SA, Mackie K, Van Bockstaele EJ (2016) Diacylglycerol lipase-α expression increases in the coeruleo-cortical pathway in dopamine-β-hydroxylase knockout mice as well as rats treated with DSP-4. Neuroscience 2016 Abstracts 77.09 / AAA24. Society for Neuroscience, San Diego, CA.

Summary: Endocannabinoids are involved in the regulation of many physiological processes including behavioral responses to stress. Endocannabinoids modulate norepinephrine (NE) signaling primarily via involvement of CB1 cannabinoid receptors (CB1r). Our previous studies have shown that acute and repeated administration of a CB1r agonist increases multiple indices of noradrenergic activity involving the locus coeruleus (LC)-frontal cortex (FC) pathway. Diacylglycerol lipase-α (DGL-α), a key enzyme in the biosynthesis of the endocannabinoid 2-arachidonoylglycerol (2-AG) is localized to both the FC and the LC. Using electron microscopy, we have recently shown that in the rat FC DGL-α is localized in postsynaptic profiles that are targeted by dopamine-β-hydroxylase (DβH), the enzyme that converts dopamine to norepinephrine and represents a marker of noradrenergic neurons (Hartman et al., 1972). In this study, we also described interactions between DGL-α, CB1r and DβH in the FC using confocal microscopy. In the present study, we investigated expression levels of DGL-α under two conditions of NE deletion: in a rat model using a systemic injection of saporin conjugated with antibody against DβH (DSP-4) and in a genetically engineered mouse that lacked the enzyme DβH (DβH-knockout, KO). We compared expression levels of DGL-α to either control rats or wild type (WT) mice using Western blot analysis. Protein extracts from micropunches of FC and LC were obtained and probed for DGL-α. Results showed that DGL-α expression was significantly increased in FC (P < 0.05) of both DSP-4 treated rats and DβHKO mice when compared to WT mice. DGL-α expression was also significantly increased in the LC (P < 0.05) of DβHKO when compared to WT mice. These data add to the accumulating evidence that dysregulation of NE transmission results in significant adaptations in the brain endocannabinoid system.

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

Benn A, Robinson E (2017) Differential roles for cortical versus sub-cortical noradrenaline and modulation of impulsivity in the rat. Psychopharmacology (Berl) 234:255-266.. doi: 10.1007/s00213-016-4458-8

Summary: Atomoxetine is a noradrenaline re-uptake inhibitor licensed for the treatment of adult and childhood attention deficit hyperactivity disorder. Although atomoxetine has established efficacy, the mechanisms which mediate its effects are not well understood. In this study, the authors investigated the role of cortical versus sub-cortical noradrenaline by using focal dopamine beta hydroxylase-saporin-induced lesions, to the prefrontal cortex (PFC) or nucleus accumbens shell (NAcSh). Male Lister hooded rats received bilateral lesions by using stereotaxic injections of the immunotoxin Anti-DβH-SAP (Cat. #IT-03), 0.02 μg in 0.5 μL per injection into the PFC and 0.004 μg in 0.2 μL per injection for NAcSh lesions. The data suggest that noradrenaline in the nucleus accumbens shell plays an important role in the effects of atomoxetine. Under these conditions, prefrontal cortex noradrenaline did not appear to contribute to atomoxetine’s effects suggesting a lack of cortical-mediated “top-down” modulation. Noradrenaline in the prefrontal cortex appears to contribute to the modulation of impulsive responding in amphetamine-treated animals, with a loss of noradrenaline associated with potentiation of its effects. These data demonstrate a potential dissociation between cortical and sub-cortical noradrenergic mechanisms and impulse control in terms of the actions of atomoxetine and amphetamine.

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

Kaushal R, Taylor B, Jamal A, Zhang L, Ma F, Donahue R, Westlund K (2016) GABA-A receptor activity in the noradrenergic locus coeruleus drives trigeminal neuropathic pain in the rat; contribution of NAα1 receptors in the medial prefrontal cortex. Neuroscience 334:148-159. doi: 10.1016/j.neuroscience.2016.08.005

Summary: The goal of this study was to investigate the role of the locus coeruleus (LC) in a rat orofacial pain model of trigeminal neuropathy induced by chronic constrictive injury of the infraorbital nerve (CCI-ION). Mechanical thresholds to von Frey filaments were tested on whisker pads to evaluate neuropathic pain behavior; pain was indicated by development of mechanical hypersensitivity. Noradrenergic (NA) neurons were lesioned with 5-mcg injections of Anti-DBH-SAP (Cat. #IT-03) into the left lateral ventricle. Mouse-IgG-SAP (Cat. #IT-18) was used as a control. After ablation of NA neurons there was a notable increase in the mechanical threshold compared to control animals. They also targeted coeruleotrigeminal NA neurons by injecting Anti-DBH-SAP into the trigeminal brainstem nuclei bilaterally in one animal and saw similar results. Injecting a GABAA receptor antagonist into the LC after injury had an inhibitory effect on nerve injury induced hypersensitivity. Injection of a NAα1 receptor antagonist, but not a NAα2 receptor antagonist, into the medial prefrontal cortex (mPFC) alleviates mechanical hypersensitivity. They conclude that GABAA-mediated activation of NA neurons during CCI-ION can facilitate hypersensitivity through NAα1 receptors in the mPFC, and that the LC is a chronic pain generator.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Mouse IgG-SAP (Cat. #IT-18)

Nam H, Kerman I (2016) A2 noradrenergic neurons regulate forced swim test immobility. Physiol Behav 165:339-349. doi: 10.1016/j.physbeh.2016.08.020

Summary: Wistar-Kyoto rats are often used as a model of depression, and exhibit high levels of immobility when subjected to a forced swim test (FST). Researchers discovered relative hyperactivation in the locus coeruleus of WKY rats compared to the genetically related Wistar rats when exposed to one- and two-day FSTs. Lesser activation of A2 noradrenergic cell group was seen by diminished levels of FOS after both days of the FST. A2 noradrenergic neurons of Winstar rats were lesioned by injecting 2.2 ug of Anti-DBH-SAP (Cat. #IT-03) into the nucleus tractus solitaris (NTS). Lesioned rats exhibited increased FST immobility on both days of the test, similar to natural WKY behavior in the same test. These data indicate that the A2 noradrenergic cell group regulates FST behavior and that its hypoactivation may contribute to the unique behavioral phenotype of WKY rats.

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

Paban V, Valable S, Baril N, Gilbert V, Chambon C, & Alescio-Lautier B (2016) Neuronal and glial changes in rat hippocampal formation after cholinergic deafferentation. J Biomol Res Ther 5(3):1000147. doi: 10.4172/2167-7956.1000147

Summary: The effects of cholinergic insult were studied in the hippocampal formation of cholinergic lesioned rats at metabolic and cellular levels by in vivo nuclear magnetic resonance spectrometry and immuno-histochemical approaches.

Usage: Cholinergic deafferentation was induced by injection of the cholinergic immunotoxin 192-IgG-SAP into the medial septum (37.5 ng/side).

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

Kumar JR, Rajkumar R, Lee LC, Dawe GS (2016) Featured Article: Targeted lesioning reveals role of nucleus incertus in the anxiogenic effect of buspirone. Targeting Trends 17(4)

Related Products: CRF-SAP (Cat. #IT-13)

Read the featured article in Targeting Trends.

See Also:

• Kumar J et al. Nucleus incertus contributes to an anxiogenic effect of buspirone in rats: Involvement of 5-HT1A receptors. Neuropharmacology 110:1-14, 2016.

Cai Y, Chew C, Muñoz F, Sengelaub D (2017) Neuroprotective effects of testosterone metabolites and dependency on receptor action on the morphology of somatic motoneurons following the death of neighboring motoneurons. Dev Neurobiol 77:691-707.. doi: 10.1002/dneu.22445

Summary: In this study the authors examined whether the protective effects of testosterone could be mediated via its androgenic or estrogenic metabolites and if these neuroprotective effects were mediated through steroid hormone receptors. Analysis was done using receptor antagonists to attempt to prevent the neuroprotective effects of hormones after partial motoneuron depletion. These motoneurons were selectively killed by intramuscular injection of CTB-SAP (2 ul, 0.1%) (Cat. #IT-14). Compared with intact normal animals, partial motoneuron depletion resulted in decreased dendritic length in remaining quadriceps motoneurons. Dendritic atrophy was attenuated with both dihydrotestosterone and estradiol treatment to a degree similar to that seen with testosterone and attenuation of atrophy was prevented by receptor blockade. Together, the results suggest that neuroprotective effects on motoneurons can be mediated by either androgenic or estrogenic hormones and require action via steroid hormone receptors, further supporting a role for hormones as neurotherapeutic agents in the injured nervous system.

Related Products: CTB-SAP (Cat. #IT-14)

Young J (2016) Hunger, thirst, sex, and sleep: How the brain controls our passions. Rowman & Littlefield Publishers.

Summary: The author reviews what has been learned about feeding, “Other clever techniques have confirmed that leptin specifically acts upon NPY-containing neurons to depress feeding. One technique is to infuse the hypothalamus with a form of NPY that is linked to a poisonous molecule called saporin. Neurons that normally contain NPY usually release it into their surroundings and then specifically take it back up into the cell so that it is not wasted. When NPY-containing neurons are tricked into taking up NPY linked to saporin, they die but leave other adjacent neurons completely unaffected. Rats treated in this way become completely insensitive to the feeding-restraining effects of leptin because they lack NPY-containing neurons in the arcuate nucleus.”

Related Products: Blank-SAP (Cat. #IT-21), NPY-SAP (Cat. #IT-28)

See Also:

• Bugarith K et al. Basomedial hypothalamic injections of neuropeptide Y conjugated to saporin selectively disrupt hypothalamic controls of food intake. Endocrinology 146(3):1179-1191, 2005.

Silva T, Takakura A, Moreira T (2016) Acute hypoxia activates hypothalamic paraventricular nucleus-projecting catecholaminergic neurons in the C1 region. Exp Neurol 285:1-11. doi: 10.1016/j.expneurol.2016.08.016

Summary: Catecholaminergic C1 cells reside in the rostral and intermediate portions of the ventrolateral medulla (RVLM) and can be activated by hypoxia. These neurons regulate the hypothalamic pituitary axis via direct projections to the hypothalamic paraventricular nucleus (PVH) and regulate the autonomic nervous system via projections to sympathetic and parasympathetic preganglionic neurons. The present results suggest that catecholaminergic C1-PVH projection is hypoxia-sensitive and the pathway between these two important brain areas can be one more piece in the complex puzzle of neural control of autonomic regulation during hypoxia. Male Wistar rats were injected with the targeted toxin Anti-DβH-SAP (Cat. #IT-03), 21 ng/100 nl, or saline, unilaterally into the PVH using the following coordinates: 1.2 mm caudal to bregma, 0.4 mm lateral to the midline and 7.8 mm below the dura mater. The author’s work adds a piece in the complex puzzle of the physiological role of the C1 cells by showing that this catecholaminergic group of cells must be activated only in emergency situations such as acute hypoxia, producing autonomic, metabolic, and neuroendocrine responses designed to help the organism survive major acute physical stresses.

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