targeted-toxins

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)

Coradazzi M, Gulino R, Fieramosca F, Falzacappa L, Riggi M, Leanza G (2016) Selective noradrenaline depletion impairs working memory and hippocampal neurogenesis. Neurobiol Aging 48:93-102. doi: 10.1016/j.neurobiolaging.2016.08.012

Summary: Neuronal loss in the locus coeruleus (LC) of Alzheimer’s patients is well known, but the contribution of LC-derived noradrenergic afferents to learning and memory function is unknown. To model noradrenergic neuron degeneration in the LC, rats were bilaterally injected directly into the LC with 0.2 ug of Anti-DBH-SAP (Cat. #IT-03). Lesioned and sham-lesioned animals were tested behaviorally and exhibited robust working memory deficits but lesioning did not affect reference memory. They concluded that ascending noradrenergic afferents might be involved in more complex aspects of working memory, possibly via newly generated progenitors in the hippocampus.

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

Kucinski A, de Jong IEM, Sarter M (2017) Reducing falls in Parkinson’s disease: interactions between donepezil and the 5‐HT6 receptor antagonist idalopirdine on falls in a rat model of impaired cognitive control of complex movements. Eur J Neurosci 45:217-231.. doi: 10.1111/ejn.13354

Objective: To assess the effects of treatment on MCMCT performance and attention in DL rats. The combined treatment of the acetylcholinesterase inhibitor donepezil and the 5-HT6 receptor antagonist idalopirdine (Lu AE58054) was use because it has been reported to exhibit synergistic pro-cholinergic activity in rats and improved cognition in patients with moderate Alzheimer’s disease.

Summary: This treatment may reduce fall propensity in patients.

Usage: 192-IgG-SAP aCSF infused bilaterally (120 ng/uL; 0.5 uL/hemisphere).

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

Araldi D, Ferrari L, Levine J (2016) Gi-protein-coupled 5-HT1B/D receptor agonist sumatriptan induces type I hyperalgesic priming. Pain 157:1773-1782. doi: 10.1097/j.pain.0000000000000581

Summary: The present study explored the possibility that, like MOR and A1-adenosine receptor agonists, triptans would also induce type II hyperalgesic priming. In addition, they explored the 5-HT receptor subtypes at which triptans act (5-HT1B, 5-HT1D and 5-HT7) to induce priming. They report that while sumatriptan, a prototypical 5-HT1B/D receptor agonist induces hyperalgesic priming, this priming meets the criteria for type I rather than type II priming. Isolectin B4 (IB4)-saporin (Cat. #IT-10), was diluted in saline, and a dose of 3.2 μg, in a volume of 20 μL was administered intrathecally to rats. The neurotoxin [Sar9,Met(O2) 11]-substance P-saporin (SSP-Saporin, Cat. #IT-11) was diluted in saline, and a dose of 100 ng, in a volume of 20 μL was administered intrathecally. In a model of pain chronification, sumatriptan induces both mechanical hyperalgesia at the site of injection and type I hyperalgesic priming, in nociceptors innervating the cutaneous injection site.

Related Products: IB4-SAP (Cat. #IT-10), SSP-SAP (Cat. #IT-11)

Ngo M, Han A, Lakatos A, Sahoo D, Hachey S, Weiskopf K, Beck A, Weissman I, Boiko A (2016) Antibody therapy targeting CD47 and CD271 effectively suppresses melanoma metastasis in patient-derived xenografts. Cell Rep 16:1701-1716. doi: 10.1016/j.celrep.2016.07.004

Summary: The high rate of metastasis and recurrence among melanoma patients indicates the presence of cells within melanoma that have the ability to both initiate metastatic programs and bypass immune recognition. The authors identified CD47 as a regulator of melanoma tumor metastasis and immune evasion. The study involved antibody-mediated blockade of CD47 coupled with targeting of CD271+ melanoma cells by way of ME20.4-SAP (Cat. #IT-15). Mice bearing human melanoma tumor (M213 or M727) were randomized into four treatment groups with one of those groups receiving treatment with ME20.4-SAP. 1 ug in 50 ul volumes were injected directly into the center mass of the tumor once every 2 days. A therapeutic effect was observed where tumor metastasis in patient-derived xenografts was strongly inhibited when treated with the combination of antibody-mediated blockade of CD47 and targeted with ME20.4-SAP.

Related Products: ME20.4-SAP (Cat. #IT-15)

Kumar J, Rajkumar R, Lee L, Dawe G (2016) Nucleus incertus contributes to an anxiogenic effect of buspirone in rats: Involvement of 5-HT1A receptors. Neuropharmacology 110:1-14. doi: 10.1016/j.neuropharm.2016.07.019

Summary: The nucleus incertus (NI) is involved in stress and anxiety responses. The NI is a cluster of GABAergic neurons in the brainstem, and coexpresses CRF, 5-HT1A and D2 receptors. Buspirone is a partial agonist of 5-HT1A receptors, an antagonist of D2 receptors, and activates the NI. Buspirone is an anti-anxiety drug, but preclinical studies showed that it induces anxiety at high doses. To see if the NI is necessary for the anxiogenic effects of high doses of buspirone, rats were bilaterally injected with 86 ng of CRF-SAP (Cat. #IT-13) into the NI. Blank-SAP (Cat. #IT-21) was used as a control. NI lesioning alone had an anxiogenic effect in several anxiety screening tests compared to sham-lesioned rats, which suggests that the NI reduces anxiety physiologically. Lesioning with CRF-SAP reduced the anxiogenic effects of intra-NI injections of buspirone. No significant difference in the anxiety screening tests resulted from injecting quinpiole, a D2 agonist, which suggests that the 5HT1A receptors in the NI are involved in the anxiogenic effects of buspirone.

Related Products: CRF-SAP (Cat. #IT-13), Blank-SAP (Cat. #IT-21)

Read the featured article in Targeting Trends.

Gilabert-Oriol R, Thakur M, Haussmann K, Niesler N, Bhargava C, Görick C, Fuchs H, Weng A (2016) Saponins from Saponaria officinalis L. augment the efficacy of a Rituximab-immunotoxin. Planta Med 82:1525-1531. doi: 10.1055/s-0042-110495

Summary: It is known that triterpenoidal saponins that come from Saponaria officinalis, the plant that saporin comes from, increases the cytotoxicity of saporin by modulating its intracellular trafficking. Investigators wanted to know if this could increase the therapeutic affect of Rituximab-Saporin. In the presence of saponins, Rituximab-Saporin had a 700-fold increase in efficacy. Concentrations of 0.0001-1nM of Anti-CD22-SAP (Cat. #IT-37) and 0.001-10nM of Anti-CD25-SAP (Cat. #IT-24) were also tested in vitro with saponins for comparison. They saw a 170-fold and 25-fold increase in cytotoxicity, respectively. All conjugates were tested on Ramos cells, and differing levels of receptor expression could explain the drastic differences in cytotoxicity enhancement.

Related Products: Anti-CD22-SAP human (Cat. #IT-37), Anti-CD25-SAP human (Cat. #IT-24)