SCHWANN CELLS MODULATE THE RELEASE OF CALCITONIN GENE-RELATED PEPTIDE FROM SENSORY NEURONS

poster abstractAn alteration in the interaction between Schwann cells and sensory neurons may be involved in inflammatory neuropathies associated with altered sensation and pain. The release of the peptide transmitter, calcitonin gene-related peptide (CGRP), is one method to monitor the sensitivity of a subclass of primary sensory neurons involved in pain signaling. We utilized an in vitro assay to investigate the interaction between Schwann cells and sensory neurons in an inflammatory state. Schwann cells and sensory neurons were isolated from adult mouse sciatic nerve and dorsal root ganglia, respectively, and maintained in culture. Schwann cells were exposed to HEPES buffer containing the inflammatory mediators histamine, prostaglandin E2, bradykinin, and serotonin (all 10-5 M), potassium (7 mM), and at pH 7.0 for 10 minutes. After this activation, the Schwann cells were incubated in HEPES buffer alone for 1 hour. This Schwann cell-conditioned buffer (SCCB) was collected and sensory neurons were exposed to three consecutive 10 minute incubations in HEPES buffer alone or SCCB. The amount of CGRP released during each of these incubations was measured using radioimmunoassay. Incubation with SCCB elicited a seven-fold increase in the release of CGRP compared to neurons exposed to HEPES buffer alone. The release of CGRP elicited by SCCB was abolished when neurons were exposed to SCCB containing no added calcium. After treatment with the inflammatory mediators detailed above for 10 minutes, Schwann cell lysates showed a significant decrease in six cytokines, while SCCB demonstrated an increase in interleukin-6 (IL-6) as measured by a cytokine array panel. These results suggest that during inflammation, Schwann cells release substances, which directly stimulate sensory neurons, as measured by an increase in CGRP release. These findings reinforce the importance of identifying the mechanisms underlying the interaction between Schwann cells and sensory neurons to discover novel therapeutics for treating inflammatory pain

The Need for Speed in Rodent Locomotion Analyses.

Locomotion analysis is now widely used across many animal species to understand the motor defects in disease, functional recovery following neural injury, and the effectiveness of various treatments. More recently, rodent locomotion analysis has become an increasingly popular method in a diverse range of research. Speed is an inseparable aspect of locomotion that is still not fully understood, and its effects are often not properly incorporated while analyzing data. In this hybrid manuscript, we accomplish three things: (1) review the interaction between speed and locomotion variables in rodent studies, (2) comprehensively analyze the relationship between speed and 162 locomotion variables in a group of 16 wild-type mice using the CatWalk gait analysis system, and (3) develop and test a statistical method in which locomotion variables are analyzed and reported in the context of speed. Notable results include the following: (1) over 90% of variables, reported by CatWalk, were dependent on speed with an average R2 value of 0.624, (2) most variables were related to speed in a nonlinear manner, (3) current methods of controlling for speed are insufficient, and (4) the linear mixed model is an appropriate and effective statistical method for locomotion analyses that is inclusive of speed-dependent relationships. Given the pervasive dependency of locomotion variables on speed, we maintain that valid conclusions from locomotion analyses cannot be made unless they are analyzed and reported within the context of speed

Adipose-derived stem cell conditioned medium impacts asymptomatic peripheral neuromuscular denervation in the mutant superoxide dismutase (G93A) transgenic mouse model of amyotrophic lateral sclerosis

Background:Amyotrophic lateral sclerosis (ALS) is devastating, leading to paralysis and death. Disease onset begins pre-symptomatically through spinal motor neuron (MN) axon die-back from musculature at ∼47 days of age in the mutant superoxide dismutase 1 (mSOD1G93A) transgenic ALS mouse model. This period may be optimal to assess potential therapies. We previously demonstrated that post-symptomatic adipose-derived stem cell conditioned medium (ASC-CM) treatment is neuroprotective in mSOD1G93A mice. We hypothesized that early disease onset treatment could ameliorate neuromuscular junction (NMJ) disruption. Objective:To determine whether pre-symptom administration of ASC-CM prevents early NMJ disconnection. Methods:We confirmed the NMJ denervation time course in mSOD1G93A mice using co-labeling of neurofilament and post-synaptic acetylcholine receptors (AchR) by α-bungarotoxin. We determined whether ASC-CM ameliorates early NMJ loss in mSOD1G93A mice by systemically administering 200μl ASC-CM or vehicle medium daily from post-natal days 35 to 47 and quantifying intact NMJs through co-labeling of neurofilament and synaptophysin with α-bungarotoxin in gastrocnemius muscle. Results:Intact NMJs were significantly decreased in 47 day old mSOD1G93A mice (p < 0.05), and daily systemic ASC-CM prevented disease-induced NMJ denervation compared to vehicle treated mice (p < 0.05). Conclusions:Our results lay the foundation for testing the long-term neurological benefits of systemic ASC-CM therapy in the mSOD1G93A mouse model of ALS

Identification of a resilient mouse facial motoneuron population following target disconnection by injury or disease

Background: When nerve transection is performed on adult rodents, a substantial population of neurons survives short-term disconnection from target, and the immune system supports this neuronal survival, however long-term survival remains unknown. Understanding the effects of permanent axotomy on cell body survival is important as target disconnection is the first pathological occurrence in fatal motoneuron diseases such as amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA). Objective: The goal of this study was to determine if facial motoneurons (FMN) could survive permanent target disconnection up to 26 weeks post-operation (wpo) after facial nerve axotomy (FNA). In addition, the potentially additive effects of immunodeficiency and motoneuron disease on post-axotomy FMN survival were examined. Methods: This study included three wild type (WT) mouse strains (C57BL/6J, B6SJL, and FVB/NJ) and three experimental models (RAG-2-/-: immunodeficiency; mSOD1: ALS; Smn-/-/SMN2+/+: SMA). All animals received a unilateral FNA, and FMN survival was quantified at early and extended post-operative timepoints. Results: In the C57BL/6J WT group, FMN survival significantly decreased at 10 wpo (55 ± 6%), and then remained stable out to 26 wpo (47 ± 6%). In the RAG-2-/- and mSOD1 groups, FMN death occurred much earlier at 4 wpo, and survival plateaued at approximately 50% at 10 wpo. The SMA model and other WT strains also exhibited approximately 50% FMN survival after FNA. Conclusion: These results indicate that immunodeficiency and motoneuron disease accelerate axotomy-induced neuron death, but do not increase total neuron death in the context of permanent target disconnection. This consistent finding of a target disconnection-resilient motoneuron population is prevalent in other peripheral nerve injury models and in neurodegenerative disease models as well. Characterization of the distinct populations of vulnerable and resilient motoneurons may reveal new therapeutic approaches for injury and disease

Identification of B6SJL mSOD1(G93A) mouse subgroups with different disease progression rates

Disease progression rates among patients with amyotrophic lateral sclerosis (ALS) vary greatly. Although the majority of affected individuals survive 3-5 years following diagnosis, some subgroups experience a more rapidly progressing form, surviving less than 1 year, and other subgroups experience slowly progressing forms, surviving nearly 50 years. Genetic heterogeneity and environmental factors pose significant barriers in investigating patient progression rates. Similar to the case for humans, variation in survival within the mSOD1 mouse has been well documented, but different progression rates have not been investigated. The present study identifies two subgroups of B6SJL mSOD1(G93A) mice with different disease progression rates, a fast progression group (FPG) and slow progression group, as evidenced by differences in the rate of motor function decline. In addition, increased disease-associated gene expression within the FPG facial motor nucleus confirmed the presence of a more severe phenotype. We hypothesize that a more severe disease phenotype could be the result of 1) an earlier onset of axonal disconnection with a consistent degeneration rate or 2) a more severe or accelerated degenerative process. We performed a facial nerve transection axotomy in both mSOD1 subgroups prior to disease onset as a method to standardize the axonal disconnection. Instead of leading to comparable gene expression in both subgroups, this standardization did not eliminate the severe phenotype in the FPG facial nucleus, suggesting that the FPG phenotype is the result of a more severe or accelerated degenerative process. We theorize that these mSOD1 subgroups are representative of the rapid and slow disease phenotypes often experienced in ALS

Health profiles of 996 melanoma survivors: the M. D. Anderson experience

BACKGROUND: The incidence and survival of melanoma are increasing, but little is known about its long-term health effects in adult survivors. METHODS: A health survey was available from 996 melanoma survivors (577 treated with surgery alone, and 391 with combined treatments). Their medical/physiologic and psychosocial responses were analyzed and compared with those of the survivors from other cancers. RESULTS: The melanoma survivors were 44.8 ± 12.8 years of age at diagnosis (significantly younger than the survivors of other cancers) and 63.7 ± 12.8 years at survey. Melanoma survivors were less likely to report that cancer had affected their health than survivors of other cancers (15.8% vs. 34.9%). The 577 individuals treated with surgery alone reported arthritis/osteoporosis, cataracts, and heart problems most frequently (less often than survivors of other cancers). The 391 individuals who had undergone combined treatments reported circulation problems and kidney problems generally as often as survivors of other cancers. Health problems were not associated with number of decades since diagnosis but with age at diagnosis, treatment modality, and family relationships. CONCLUSION: We present information from a large cohort of long-term survivors of melanoma. As a group, they were less likely to report that cancer had affected their overall health than survivors of other cancers; a number of disease related and psychosocial factors appear to influence their health profiles

Ret-dependent and Ret-independent mechanisms of Gfl-induced sensitization

Abstract Background The GDNF family ligands (GFLs) are regulators of neurogenic inflammation and pain. We have previously shown that GFLs increase the release of the sensory neuron neuropeptide, calcitonin gene-related peptide (CGRP) from isolated mouse DRG. Results Inhibitors of the mitogen-activated protein kinase (MAPK) pathway abolished the enhancement of CGRP release by GDNF. Neurturin-induced enhancement in the stimulated release of CGRP, used as an indication of sensory neuronal sensitization, was abolished by inhibition of the phosphatidylinositol-3 kinase (PI-3K) pathway. Reduction in Ret expression abolished the GDNF-induced sensitization, but did not fully inhibit the increase in stimulus-evoked release of CGRP caused by neurturin or artemin, indicating the presence of Ret-independent GFL-induced signaling in sensory neurons. Integrin β-1 and NCAM are involved in a component of Ret-independent GFL signaling in sensory neurons. Conclusions These data demonstrate the distinct and variable Ret-dependent and Ret-independent signaling mechanisms by which GFLs induce sensitization of sensory neurons. Additionally, there is a clear disconnect between intracellular signaling pathway activation and changes in sensory neuronal function.</p

Locomotor analysis identifies early compensatory changes during disease progression and subgroup classification in a mouse model of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis is a motoneuron degenerative disease that is challenging to diagnose and presents with considerable variability in survival. Early identification and enhanced understanding of symptomatic patterns could aid in diagnosis and provide an avenue for monitoring disease progression. Use of the mSOD1G93A mouse model provides control of the confounding environmental factors and genetic heterogeneity seen in amyotrophic lateral sclerosis patients, while investigating underlying disease-induced changes. In the present study, we performed a longitudinal behavioral assessment paradigm and identified an early hindlimb symptom, resembling the common gait abnormality foot drop, along with an accompanying forelimb compensatory mechanism in the mSOD1G93A mouse. Following these initial changes, mSOD1 mice displayed a temporary hindlimb compensatory mechanism resembling an exaggerated steppage gait. As the disease progressed, these compensatory mechanisms were not sufficient to sustain fundamental locomotor parameters and more severe deficits appeared. We next applied these initial findings to investigate the inherent variability in B6SJL mSOD1G93A survival. We identified four behavioral variables that, when combined in a cluster analysis, identified two subpopulations with different disease progression rates: a fast progression group and a slow progression group. This behavioral assessment paradigm, with its analytical approaches, provides a method for monitoring disease progression and detecting mSOD1 subgroups with different disease severities. This affords researchers an opportunity to search for genetic modifiers or other factors that likely enhance or slow disease progression. Such factors are possible therapeutic targets with the potential to slow disease progression and provide insight into the underlying pathology and disease mechanisms

Labels, identity, and narratives in children with primary speech and language impairments

Over time, the labels used for various speech and language impairments change. For example, language impairment in children has been called developmental dysphasia/aphasia, language impairment/ disorder/delay/difficulties (Bishop, 2013). Changes in labels reflect our evolving understanding of the nature of a disorder but also the changing social context and mores. Currently a number of terms are in use for speech and language impairments which may be used differently by practitioners and researchers in education and health contexts. For example, the phrase ‘speech, language, and communication needs’ (SLCN) was coined in the UK by the Bercow review to encompass the widest range of these impairments. However the term is used and understood in a variety of ways by different professionals and not used at all by parents (Dockrell, Lindsay, Roulstone, & Law, 2014; Roulstone & Lindsay, 2012). The use of other labels such as specific language impairment or language delay is by no means straightforward as recent debates have illustrated (Bishop, 2014; Reilly et al., 2014). That debate reflected the views of academics, clinicians, educators, and parents (Bishop, 2014; Huneke & Lascelles, 2014; Lauchlan & Boyle, 2014). While professionals debate the best label to describe language impairments, it is evident that language impairments are not well understood in the public domain when compared with other diagnostic categories such as Autism, and ADHD (Kamhi, 2004)