Mouse Anti Human DMPK Hybridoma [NBOEN22 7C7]

Objective We aimed to determine whether 3D imaging reconstruction allows identifying molecular:clinical associations in myotonic dystrophy type 1 (DM1). Methods We obtained myoblasts from 6 patients with DM1 and 6 controls. We measured cytosine-thymine-guanine (CTG) expansion and detected RNA foci and muscleblind like 1 (MBNL1) through 3D reconstruction. We studied dystrophia myotonica protein kinase (DMPK) expression and splicing alterations of MBNL1, insulin receptor, and sarcoplasmic reticulum Ca(2+)-ATPase 1. Results Three-dimensional analysis showed that RNA foci (nuclear and/or cytoplasmic) were present in 45%-100% of DM1-derived myoblasts we studied (range: 0-6 foci per cell). RNA foci represented <0.6% of the total myoblast nuclear volume. CTG expansion size was associated with the number of RNA foci per myoblast (r= 0.876 [95% confidence interval 0.222-0.986]) as well as with the number of cytoplasmic RNA foci (r= 0.943 [0.559-0.994]). Although MBNL1 colocalized with RNA foci in all DM1 myoblast cell lines, colocalization only accounted for 1% of total MBNL1 expression, with the absence of DM1 alternative splicing patterns. The number of RNA foci was associated with DMPK expression (r= 0.967 [0.079-0.999]). On the other hand, the number of cytoplasmic RNA foci was correlated with the age at disease onset (r= -0.818 [-0.979 to 0.019]). Conclusions CTG expansion size modulates RNA foci number in myoblasts derived from patients with DM1. MBNL1 sequestration plays only a minor role in the pathobiology of the disease in these cells. Higher number of cytoplasmic RNA foci is related to an early onset of the disease, a finding that should be corroborated in future studies.

This review emphasizes the benefits of ultra-high-pressure liquid chromatography (UHPLC) in the context of in-vitro drug-metabolism and pharmacokinetics (DMPK) studies. The analysis throughput afforded by UHPLC is particularly useful during the early DMPK stages, when rapid, reliable data must be generated on a large number of new chemical entities (NCEs) to select the most appropriate drug candidates. UHPLC also offers high chromatographic resolution, an important feature for the identification of unknown metabolites that are potentially generated from NCEs by a few dozen biochemical enzymes and combinations of them. Most DMPK studies require selectivity and peak-assignment certainty that is only afforded by mass spectrometry (MS) detectors. We therefore thoroughly discuss the use of UHPLC-MS and UHPLC-tandem MS with regard to DMPK, highlighting the coupling of UHPLC with quadrupole-based MS analyzers, time-of-flight MS analyzers and hybrid analyzers. (C) 2014 Elsevier B.V. All rights reserved.