Citations

Deletion of the major adenylate kinase AK1 isoform, which catalyzes adenine nucleotide exchange, disrupts cellular energetic economy and compromises metabolic signal transduction. However, the consequences of deleting the AK1 gene on cardiac energetic dynamics and performance in the setting of ischemia-reperfusion have not been determined. Here, at the onset of ischemia, AK1 knockout mice hearts displayed accelerated loss of contractile force compared with wild-type controls, indicating reduced tolerance to ischemic stress. On reperfusion, AK1 knockout hearts demonstrated reduced nucleotide salvage, resulting in lower ATP, GTP, ADP, and GDP levels and an altered metabolic steady state associated with diminished ATP-to-Piand creatine phosphate-to-Piratios. Postischemic AK1 knockout hearts maintained ∼40% of β-phosphoryl turnover, suggesting increased phosphotransfer flux through remaining adenylate kinase isoforms. This was associated with sustained creatine kinase flux and elevated cellular glucose-6-phosphate levels as the cellular energetic system adapted to deletion of AK1. Such metabolic rearrangements, along with sustained ATP-to-ADP ratio and total ATP turnover rate, maintained postischemic contractile recovery of AK1 knockout hearts at wild-type levels. Thus deletion of the AK1 gene reveals that adenylate kinase phosphotransfer supports myocardial function on initiation of ischemic stress and safeguards intracellular nucleotide pools in postischemic recovery.

The aerial parts of Amphoricarpos neumayeri ssp. murbeckii afforded eleven guaianolides with the same relative (1αH,4β H,5αH,7αH) configuration of the basic skeleton. All of them contained a CH2OX (X = H, acetyl or isovaleroyl) group in 4α-position, typical for amphoricarpolides. Four compounds (1 - 4) were isolated before from the same species, originating from different localities. Guaianolides 5 - 11 are new compounds. Compounds 7 and 8 were epoxidized at the 10α(14)-position. Instead of the Δ11(13)-double bond, observed in all previously isolated guaianolides from the same species, the four lactones contained 11α,13-diol (8 - 10) or 11α-OH,13-chloro (11) moieties respectively.

PurposeArchived formalin‐fixed paraffin‐embedded (FFPE) tissue collections represent a valuable informational resource for numerous studies. However, there is no NMR signal from FFPE specimens at room temperature. To obtain MR images and enable comparison of magnetic resonance microscopy (MRM) and histology studies we propose to image FFPE tissue at elevated temperature.MethodsA FFPE tissue block was imaged at 7 Tesla (T) and 16.4T at 70–80°C using T2‐weighting methods. The only difference from standard MR microscopy (MRM) is elevated temperature at which the embedding medium melts.ResultsUsing FFPE murine brain tissue, we were able to demonstrate the feasibility of tissue MRM from paraffin embedded specimens. Histology images taken from the specimen after MRM demonstrate that keeping the FFPE specimen in paraffin melt at 70–80°C for dozens of hours does not affect subsequent histology analysis.ConclusionMRM of FFPE tissue from paraffin melt opens new avenues for analyzing archived histological specimens (biopsies, post mortem, etc.) and for correlating MR images with histology (optical microscopy). In addition, 3D MRM of FFPE specimens could guide histology in search for appropriate regions of interest and subsequently minimize occurrences of false negatives in tissue analysis. Magn Reson Med 71:1989–1994, 2014. © 2014 Wiley Periodicals, Inc.

We propose to use organic and mixed solvents for nuclear magnetic resonance microscopy of fixed tissue as a means for improving image information content. NMR properties of some standard solvents (methanol, acetone, DMSO) and solvents in use for tissue processing in pathology (xylenes, paraffin, ?Clearify?) have been measured, reviewed, and analyzed. It was found that DMSO and paraffin are very useful solvents that provide images of better quality than those obtained in water (neutralized formalin buffer). This is illustrated on the formalin fixed mouse brain sections imaged at 16.4 teslas (700 MHz).

Next-generation screening of disease-related metabolomic phenotypes requires monitoring of both metabolite levels and turnover rates. Stable isotope18O-assisted31P nuclear magnetic resonance (NMR) and mass spectrometry uniquely allows simultaneous measurement of phosphometabolite levels and turnover rates in tissue and blood samples. The18O labeling procedure is based on the incorporation of one18O into Pifrom [18O]H2O with each act of ATP hydrolysis and the distribution of18O-labeled phosphoryls among phosphate-carrying molecules. This enables simultaneous recording of ATP synthesis and utilization, phosphotransfer fluxes through adenylate kinase, creatine kinase, and glycolytic pathways, as well as mitochondrial substrate shuttle, urea and Krebs cycle activity, glycogen turnover, and intracellular energetic communication. Application of expanded18O-labeling procedures has revealed significant differences in the dynamics of G-6-P[18O] (glycolysis), G-3-P[18O] (substrate shuttle), and G-1-P[18O] (glycogenolysis) between human and rat atrial myocardium. In human atria, the turnover of G-3-P[18O], which defects are associated with the sudden death syndrome, was significantly higher indicating a greater importance of substrate shuttling to mitochondria. Phosphometabolomic profiling of transgenic hearts deficient in adenylate kinase (AK1−/−), which altered levels and mutations are associated to human diseases, revealed a stress-induced shift in metabolomic profile with increased CrP[18O] and decreased G-1-P[18O] metabolic dynamics. The metabolomic profile of creatine kinase M-CK/ScCKmit−/−-deficient hearts is characterized by a higher G-6-[18O]P turnover rate, G-6-P levels, glycolytic capacity, γ/β-phosphoryl of GTP[18O] turnover, as well as β-[18O]ATP and β-[18O]ADP turnover, indicating altered glycolytic, guanine nucleotide, and adenylate kinase metabolic flux. Thus,18O-assisted gas chromatography-mass spectrometry and31P NMR provide a suitable platform for dynamic phosphometabolomic profiling of the cellular energetic system enabling prediction and diagnosis of metabolic diseases states.

Abstract Genomic perturbations that challenge normal signaling at the pluripotent stage may trigger unforeseen ontogenic aberrancies. Anticipatory systems biology identification of transcriptome landscapes that underlie latent phenotypes would offer molecular diagnosis before the onset of symptoms. The purpose of this study was to assess the impact of calreticulin-deficient embryonic stem cell transcriptomes on molecular functions and physiological systems. Bioinformatic surveillance of calreticulin-null stem cells, a monogenic insult model, diagnosed a disruption in transcriptome dynamics, which re-prioritized essential cellular functions. Calreticulin-calibrated signaling axes were uncovered, and network-wide cartography of undifferentiated stem cell transcripts suggested cardiac manifestations. Calreticulin-deficient stem cell-derived cardiac cells verified disorganized sarcomerogenesis, mitochondrial paucity, and cytoarchitectural aberrations to validate calreticulin-dependent network forecasts. Furthermore, magnetic resonance imaging and histopathology detected a ventricular septal defect, revealing organogenic manifestation of calreticulin deletion. Thus, bioinformatic deciphering of a primordial calreticulin-deficient transcriptome decoded at the pluripotent stem cell stage a reconfigured multifunctional molecular registry to anticipate predifferentiation susceptibility toward abnormal cardiophenotype.