isolation-of-murine-valve-endothelial-cells

Isolation of Murine Valve Endothelial Cells

Normal valve structures consist of stratified layers of specialized extracellular matrix (ECM) interspersed with valve interstitial cells (VICs) and ...

The Ohio State University

The Research Institute at Nationwide Children's Hospital

Charcot-Marie-Tooth disease type 1A (CMT1A) is caused by a 1.4 Mb duplication on chromosome 17p11.2, which contains the peripheral myelin protein-22 (PMP22) gene. Increased levels of PMP22 in compact myelin of peripheral nerves have been demonstrated and presumed to cause the phenotype of CMT1A. The objective of the present study was to determine whether an extra copy of the PMP22 gene in CMT1A disrupts the normally coordinated expression of PMP22 protein in peripheral nerve myelin and to evaluate PMP22 over-expression in patients with CMT1A and determine whether levels of PMP22 are molecular markers of disease severity. PMP22 expression was measured by taking skin biopsies from patients with CMT1A (n = 20) and both healthy controls (n = 7) and patients with Hereditary Neuropathy with liability to Pressure Palsies (HNPP) (n = 6), in which patients have only a single copy of PMP22. Immunological electron microscopy was performed on the skin biopsies to quantify PMP22 expression in compact myelin. Similar biopsies were analysed by real time PCR to measure PMP22 mRNA levels. Results were also correlated with impairment in CMT1A, as measured by the validated CMT Neuropathy Score. Most, but not all patients with CMT1A, had elevated PMP22 levels in myelin compared with the controls. The levels of PMP22 in CMT1A were highly variable, but not in HNPP or the controls. However, there was no correlation between neurological disabilities and the level of over-expression of PMP22 protein or mRNA in patients with CMT1A. The extra copy of PMP22 in CMT1A results in disruption of the tightly regulated expression of PMP22. Thus, variability of PMP22 levels, rather than absolute level of PMP22, may play an important role in the pathogenesis of CMT1A.

PMP22 expression in dermal nerve myelin from patients with CMT1A.

Huntington disease (HD) is a disorder characterized by chorea, dystonia, bradykinesia, cognitive decline and psychiatric comorbidities. Balance and gait impairments, as well as falls, are common manifestations of the disease. The importance of compensatory rapid stepping to maintain equilibrium in older adults is established, yet little is known of the role of stepping response times (SRTs) in balance control in people with HD. SRTs and commonly-used clinical measures of balance and mobility were evaluated in fourteen symptomatic participants with HD, and nine controls at a university mobility research laboratory. Relative and absolute reliability, as well as minimal detectable change in SRT were quantified in the HD participants. HD participants exhibited slower SRTs and poorer dynamic balance, mobility and motor performance than controls. HD participants also reported lower balance confidence than controls. Deficits in SRT were associated with low balance confidence and impairments on clinical measures of balance, mobility, and motor performance in HD participants. Measures of relative and absolute reliability indicate that SRT is reliable and reproducible across trials in people with HD. A moderately low percent minimal detectable change suggests that SRT appears sensitive to detecting real change in people with HD. SRT is impaired in people with HD and may be a valid and objective marker of disease progression.

Deficits in stepping response time are associated with impairments in balance and mobility in people with Huntington disease.

Charcot-Marie-Tooth disease (CMT) affects 1 in 2,500 people and is caused by mutations in more than 30 genes. Identifying the genetic cause of CMT is often necessary for family planning, natural history studies, and for entry into clinical trials. However genetic testing can be both expensive and confusing to patients and physicians.

Charcot-Marie-Tooth disease subtypes and genetic testing strategies.

Mutations in MPZ cause CMT1B, the second most frequent cause of CMT1. Elegant studies with Ser63del mice suggest that Ser63del MPZ is retained in the ER where it activates the unfolded protein response (UPR) that contributes to the neuropathy. Clinical information about patients with this mutation is limited. We present clinical and electrophysiological data on a large multigenerational family with CMT1B caused by Ser63del MPZ. The patients have a classical CMT1 phenotype that is much less severe than that of patients with Arg98Cys MPZ that also activates the UPR. These results suggest that clinical presentation along cannot predict which MPZ mutations will be retained in the ER and activate the UPR.

Phenotypic presentation of the Ser63Del MPZ mutation.

CMT1A is the most common form of Charcot-Marie-Tooth disease (CMT), a slowly progressive neuropathy in which impairment is length dependent. Fibular nerve conduction studies to the anterior tibialis muscle (AT) may serve as a physiological marker of disease progression in patients with CMT1A. The objective of this study is to determine whether the AT compound muscle action potential (CMAP) amplitude correlates with impairment in patients with CMT1A.

Anterior tibialis CMAP amplitude correlations with impairment in CMT1A.

Formation of the epicardium requires several cellular processes including migration, transformation, invasion, and differentiation in order to give rise to fibroblast, smooth muscle, coronary endothelial and myocyte cell lineages within the developing myocardium. Snai1 is a zinc finger transcription factor that plays an important role in regulating cell survival and fate during embryonic development and under pathological conditions. However, its role in avian epicardial development has not been examined.

Snai1 is important for avian epicardial cell transformation and motility.

No current medications improve neuropathy in subjects with Charcot-Marie-Tooth disease type 1A (CMT1A). Ascorbic acid (AA) treatment improved the neuropathy of a transgenic mouse model of CMT1A and is a potential therapy. A lower dosage (1.5 g/d) did not cause improvement in humans. It is unknown whether a higher dosage would prove more effective.

Article	Year
PMP22 expression in dermal nerve myelin from patients with CMT1A. Brain : a journal of neurology\| PubMed ID: 19447823	2009
Deficits in stepping response time are associated with impairments in balance and mobility in people with Huntington disease. Journal of the neurological sciences\| PubMed ID: 20804986	2010
Charcot-Marie-Tooth disease subtypes and genetic testing strategies. Annals of neurology\| PubMed ID: 21280073	2011
Phenotypic presentation of the Ser63Del MPZ mutation. Journal of the peripheral nervous system : JPNS\| PubMed ID: 22734905	2012
Anterior tibialis CMAP amplitude correlations with impairment in CMT1A. Muscle & nerve\| PubMed ID: 23456782	2013
Snai1 is important for avian epicardial cell transformation and motility. Developmental dynamics : an official publication of the American Association of Anatomists\| PubMed ID: 23553854	2013
High-dosage ascorbic acid treatment in Charcot-Marie-Tooth disease type 1A: results of a randomized, double-masked, controlled trial. JAMA neurology\| PubMed ID: 23797954	2013

Lindsey J. Miller

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