Automated Measurements of Key Morphological Features of Human Embryos for IVF

A major challenge in clinical In-Vitro Fertilization (IVF) is selecting the highest quality embryo to transfer to the patient in the hopes of achieving a pregnancy. Time-lapse microscopy provides clinicians with a wealth of information for selecting embryos. However, the resulting movies of embryos are currently analyzed manually, which is time consuming and subjective. Here, we automate feature extraction of time-lapse microscopy of human embryos with a machine-learning pipeline of five convolutional neural networks (CNNs). Our pipeline consists of (1) semantic segmentation of the regions of the embryo, (2) regression predictions of fragment severity, (3) classification of the developmental stage, and object instance segmentation of (4) cells and (5) pronuclei. Our approach greatly speeds up the measurement of quantitative, biologically relevant features that may aid in embryo selection.

Processing of the insulin-like growth factor-II-mannose 6-phosphate receptor in isolated liver subcellular fractions

A truncated, soluble form of the insulin-like growth factor-II-mannose 6-phosphate (IGF-II-M6P) receptor has been identified in serum and shown to be released from cultured tissues and cells, liver being the main contributor to serum receptor in adult rats. In the present study, the processing of the IGF-II-M6P receptor has been characterized in isolated liver subcellular fractions using ligand binding, affinity crosslinking, and Western immunoblotting techniques. The receptor in plasma membrane fractions differed from that in Golgi-endosomal fractions by: (i) a lower molecular size upon reducing polyacrylamide gel electrophoresis (245 vs. 255 kDa); (ii) a less tight membrane association as judged upon extractibility by NaCI; and (iii) the inability to recognize antibody anti-22C, directed against the cytoplasmic domain of the receptor. Incubation of cell fractions at 30 degrees C led to a pH- and time-dependent release of the receptor into the medium. The pH optimum for release was 5.5 in the Golgi-endosomal fraction and 7.5 in plasma membrane fractions; at this pH, approximately 2% and 20%-30% of total receptors were released per hour, respectively. Receptor release was inhibited in a dose-dependent manner by aprotinin, benzamidine, and leupeptin in the Golgi-endosomal fraction, and by 1,10 phenanthroline in plasma membrane fractions, although high concentrations were required for inhibition. The receptor released from Golgi-endosomes showed a 5-10 kDa reduction in size and a loss of ability to recognize antibody anti-22C, but that released from plasma membranes showed little or no changes in size. We conclude that soluble, carboxy-terminally truncated forms of the IGF-II-M6P receptor are generated from the intact receptor in isolated Golgi-endosomal and plasma membrane fractions. However, receptor processing in these fractions exhibits different properties, suggesting the involvement of different proteases.

Mutation of Cys672 allows recombinant expression of activatible macrophage-stimulating protein

We readily produced recombinant pro-macrophage stimulating protein in a mammalian expression system, but it was only weakly active after proteolytic activation. Active macrophage stimulating protein is a disulfide-bonded heterodimer, but in our hands, the subunits of recombinant macrophage stimulating protein were mostly not disulfide bonded. Molecular modeling of the serine proteinase domain of macrophage stimulating protein based on homology to human trypsin suggested that macrophage stimulating protein, but not plasminogen or hepatocyte growth factor, has a Cys residue (672) in close proximity to the Cys residue (578) that forms the intersubunit disulfide link with the other subunit. We hypothesized that Cys672 might interfere with intersubunit disulfide formation by forming an intrasubunit disulfide with Cys578 and therefore mutated Cys672 to Ala. After kallikrein activation, the subunits of Cys672 --> Ala macrophage stimulating protein were fully disulfide linked, and the mutant macrophage stimulating protein had 10-20-fold higher specific activity than the wild type recombinant macrophage stimulating protein.