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.

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Bajo V, Leach N, Cordery P, Nodal F, King A (2014) The cholinergic basal forebrain in the ferret and its inputs to the auditory cortex. Eur J Neurosci 40:2922-2940. doi: 10.1111/ejn.12653 PMID: 24945075

Summary: The ferret has become a more common animal model in auditory neuroscience. Unlike rodent models, however, anatomical data describing the organization of the basal forebrain cholinergic system and its projections to the auditory cortex have not been well characterized. Using a variety of methods the authors mapped the architecture of the ferret basal forebrain. IHC was done with several antibodies including anti-ChAT (Cat. #AB-N34AP; 1:1000) and anti-NGFr (Cat. #AB-N07; 1:500). Animals also received 17 μg of ME20.4-SAP (Cat. #IT-15) in a total of 17 injections into the ectosylvian gyrus. The results indicate that acetylcholine is most likely involved in modulation of auditory processing.

Related Products: Choline Acetyltransferase Rabbit Polyclonal, affinity-purified (Cat. #AB-N34AP), NGFr (ME20.4, p75) Mouse Monoclonal (Cat. #AB-N07), ME20.4-SAP (Cat. #IT-15)

Nodal FR, Leach ND, Keating P, Dahmen JC, King AJ, Bajo VM (2013) Spatial processing in the primary auditory cortex following cholinergic lesions of the basal forebrain in ferrets. Neuroscience 2013 Abstracts 353.09. Society for Neuroscience, San Diego, CA.

Summary: Cortical acetylcholine release has been implicated in different cognitive functions, including perceptual learning. We have recently shown that cortical cholinergic innervation is necessary for normal sound localization accuracy in ferrets, as well as for their ability to adapt with training to altered spatial cues (Leach et al., 2013, J Neurosci 33:6659-71). To explore whether these behavioral deficits are associated with changes in the spatial sensitivity of cortical neurons, we recorded neural activity in the primary auditory cortex (A1) from three animals in which cholinergic inputs had previously been reduced by making bilateral injections of the immunotoxin ME20.4-SAP in the nucleus basalis (NB). Neural activity was recorded from 146 penetrations in the left and right A1 under anesthesia (medetomidine/ketamine) using Neuronexus multi-site silicon probes. Histological analysis after the recording sessions revealed a mean loss of cholinergic neurons in the NB of 89.3±7.1% when compared to control animals, as well as a significant reduction in cholinergic fiber density across the auditory cortex, including the middle ectosylvian gyrus where A1 is located. On the basis of the location of the penetrations and electrophysiological characterization of the neural responses, which typically exhibited a mean latency of ≤20 ms, frequency tuning and onset responses with occasional weaker offset responses, we were able to assign the recordings to A1. The distribution of unit best frequencies was used to ensure that the tonotopic axis of A1 was evenly sampled. Spatial tuning was determined using virtual acoustic space stimuli comprising 200 ms broadband noise presented at three different levels (56, 70 and 84 dB SPL) from 12 locations separated by 30° in azimuth. Most of the units were broadly tuned, responding to all the virtual sound locations tested. Their spatial preferences were quantified by calculating the centroid direction vector from the variation in spike count with stimulus location within the onset response. This revealed a contralateral preference for most units, with the majority of the centroid azimuths located within the frontal hemifield. These data are consistent with the distribution of azimuth tuning previously described in the ferret, and initial comparisons with control animals have not shown any differences in spatial sensitivity in the animals with cholinergic lesions. Reduced cholinergic release therefore does not appear to influence the spatial response properties of A1 neurons in anesthetized animals, suggesting that any effects on sensory coding may only become apparent during behavior.

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Leach ND, Nodal FR, Cordery PM, King AJ, Bajo VM (2013) Cortical cholinergic input is required for normal auditory perception and experience-dependent plasticity in adult ferrets. J Neurosci 33(15):6659-6671. doi: 10.1523/JNEUROSCI.5039-12.2013

Summary: In order to study how cholinergic input from the nucleus basalis affects auditory perception and learning, the authors injected a total of 35.2 ng of ME20.4-SAP (Cat. #IT-15) into the nucleus basalis in each hemisphere of ferrets. Based on several learning tasks, the data suggest that these cholinergic inputs aid in the perception of sound source location and aid in the adaptation of the auditory system to changes in spatial cues.

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Croxson PL, Browning PG, Gaffan D, Baxter MG (2012) Acetylcholine facilitates recovery of episodic memory after brain damage. J Neurosci 32(40):13787-13795. doi: 10.1523/JNEUROSCI.2947-12.2012

Summary: Episodic memory is controlled by several interconnected brain structures. The order in which these structures sustain damage can affect the processes lost. In this work the authors performed numerous bilateral injections of ME20.4-SAP (Cat. #IT-15) into the infero-temporal cortex, the medial surface of the temporal lobe, the perirhinal and entorhinal cortex, and the temporal pole of monkeys. These injections totaled 2.2-2.5 μg of conjugate. The results indicate that loss of cortical acetylcholine function will interfere with adaptation to memory impairments caused by structural damage in episodic memory centers.

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Croxson PL, Kyriazis DA, Baxter MG (2011) Cholinergic modulation of a specific memory function of prefrontal cortex. Nat Neurosci 14(12):1510-1512. doi: 10.1038/nn.2971

Summary: The authors investigated loss of acetylcholine in the large and highly differentiated PFC’s of rhesus monkeys. The monkeys received 80-92 20-ng injections of ME20.4-SAP (Cat. #IT-15) per hemisphere. Lesioned animals were severely impaired on tasks involving spatial working memory.

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Bajo Lorenzana VM Leach ND, Cordery PM, Nodal FR, King AJ (2011) The cholinergic basal forebrain in the ferret and its inputs to the auditory cortex. IBRO 2011 Abstracts International Brain Research Organization, Florence, Italy.

Summary: Projections from the NB to the auditory cortex were investigated by injecting tracers into the NB itself (n=5), or by applying tracer deposits to the surface of the auditory cortex (n=4). Tracers included Rhodamine, Fluorescein, Cascade Blue, as well as the cholinergic immunotoxin ME20.4-SAP. Both ME20.4-SAP injections in the auditory cortex and epipial tracer deposits revealed that NB provides the main cholinergic input to the cortex, and that this projection is predominantly ipsilateral.

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Croxson PL, Baxter MG (2009) Multiple neuromodulator depletion interacts with fornix transection to impair episodic memory in monkeys. Neuroscience 2009 Abstracts 98.4/EE128. Society for Neuroscience, Chicago, IL.

Summary: Acetylcholine may play an important role in some aspects of cognitive function, and in particular in episodic memory. However, the role of other neuromodulatory (NM) substances, such as noradrenaline, dopamine, and serotonin, in episodic memory is less well-defined. We tested monkeys on a model of episodic memory in monkeys and carried out specific depletions of different neuromodulators within inferotemporal cortex (IT). Six rhesus macaque monkeys (five male) were trained on an object-in-place scene learning task that models key features of human episodic memory, because learning occurs rapidly (often in a single trial) in the contaxt of unique background scenes. After preoperative testing three monkeys were given injections into IT of the immunotoxin ME20.4-saporin interleaved with injections of 6-hydroxydopamine and 5,7-dihydroxytryptamine. This resulted in depletion of acetylcholine, dopamine, noradrenaline and serotonin throughout IT (group NM+ACh). Three monkeys received the same treatment but omitting the ME20.4-saporin, thus depleting dopamine, noradrenaline and serotonin, but sparing acetylcholine (group NM). Neither group of monkeys (NM+ACh or NM) were impaired in postoperative scene learning. We found previously that addition of fornix transection to depletion of ACh from IT severely impaired scene learning relative to fornix transection alone (Browning et al. 2009, Cerebral Cortex). Therefore we gave each monkey in groups NM and NM+ACh a bilateral fornix transection and performed a further postoperative performance test. As expected, monkeys in group NM+ACh were severely impaired in scene learning following fornix transection. However, monkeys in group NM were also severely impaired in scene learning following fornix transection, despite having no visible damage to cholinergic innervation. Depletion of cholinergic, dopaminergic, adrenergic and serotoninergic innervation of inferotemporal cortex, therefore, is not sufficient to impair monkeys’ performance on an episodic memory task. Furthermore, there is a synergistic interaction between the NM depletion and fornix transection in this task, like that between ACh depletion and fornix transection. This may be due to a general reduction in cortical function after NM depletion, albeit not sufficient to cause episodic memory impairment on its own, which exacerbates the effect of fornix transection. It may point to one or more of these neuromodulators having a role in post-lesion plasticity, a role that is also played by ACh. Importantly, these data suggest that intact cholinergic innervation is not sufficient for post-lesion plasticity.

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Browning PG, Gaffan D, Croxson PL, Baxter MG (2010) Severe scene learning impairment, but intact recognition memory, after cholinergic depletion of inferotemporal cortex followed by fornix transection. Cereb Cortex 20(2):282-293. doi: 10.1093/cercor/bhp097

Summary: In this work the authors investigated the link between connections carried by the fornix and cholinergic input to the inferotemporal cortex in scene learning. Monkeys received 56-64 0.02-µg injections of ME20.4-SAP (Cat. #IT-15) into the inferotemporal cortex, and entorhinal cortices. There was a marked impairment in memory for lesioned animals that also received a fornix transection, indicating a synergistic interaction between connections carried by the fornix and cholinergic input to the inferotemporal cortex for episodic memory.

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Croxson PL, Browning PGF, Gaffan D, Baxter MG (2008) Cholinergic depletion of the inferior temporal cortex interferes with recovery from episodic memory deficits. Neuroscience 2008 Abstracts 292.7/SS20. Society for Neuroscience, Washington, DC.

Summary: Cholinergic innervation of the temporal lobe has been suggested to have a role in episodic memory, a function which is also disrupted by lesions or disconnections of the medial temporal lobe circuit. Acetylcholine may be necessary for the specific function of some brain regions. Alternatively, it may be necessary for cortical plasticity and remodeling in those conditions in which the animal has to adapt following new task demands or injury. To investigate the role of cholinergic projections to inferotemporal cortex in episodic memory, and how loss of these projections might interact with damage to other brain structures necessary for normal memory function, we trained monkeys preoperatively on object-in-place scene discrimination problems until they could rapidly learn many problems within a testing session. Because learning occurs rapidly, mostly in a single trial, and depends on the presentation of discrimination problems in unique background scenes, this task models key features of human episodic memory. For the first stage of the experiment, the monkeys then received either a fornix transection or mammillary body ablation, both of which are known to impair learning in this task. All of the monkeys were impaired at scene learning after fornix or mammillary body lesions compared to their preoperative performance, consistent with previous results. In the second stage of the experiment, the monkeys underwent a second surgery in which we used the immunotoxin ME20.4-saporin to selectively deplete cholinergic inputs to the inferotemporal cortex. We then re-tested the monkeys on scene learning, and they were no more impaired than they were after their first surgery. This result is in striking contrast to an earlier finding by our laboratory that the effect of fornix transection is greatly exacerbated by prior depletion of acetylcholine from inferotemporal cortex (Browning et al. 2008, in press). The key difference between these two experiments is the order in which the lesions were placed: cholinergic depletion of inferotemporal cortex before fornix transection results in severe amnesia, whereas severe amnesia does not occur if the lesions are sustained in the opposite order. This finding suggests that monkeys require acetylcholine in inferotemporal cortex in order to adjust to the effects of a fornix lesion on episodic memory. This is consistent with a role for cholinergic input to neocortex in cortical plasticity and remodelling, rather than a specific role in certain brain functions such as episodic memory.

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