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Woo, W. L.

Publications and source records attributed to Woo, W. L..

3 recordsLinked to original sources

In silico prediction of cellular organelles from computationally super-resolved (SR) phase-modulated optical micrographs

Differential interference contrast (DIC) & phase contrast microscopy (PCM) represent 2 widely-assimilated optical microscopical imaging modalities often employed for live cell imaging (LCI) applications. Although both of these approaches have marked advantages over traditional brightfield (BF) microscopy (they dont require staining and provide real time visualization of cellular dynamics & metabolomics), there is a need to often supplement these modalities with epifluorescent microscopical imaging for the detection of specific organelles and structures in vivo (a process known as fluorescence combination/colocalization microscopy). Nonetheless, epifluorescent microscopy (both widefield and confocal) rely on the use of fluorophores (specialized fluorescent molecules and/or fluorescent proteins) for labelling key structures and features in the cell, which are prone to several issues, including photobleaching or cross-talk (amongst others). In this context, we seek to develop a novel deep neural network (DNN)-based approach aimed at predicting the location of 3 specific organelles (the cell nucleus, mitochondria & Golgi Apparatus) from acquired PCM & DIC images which have been super-resolved (SR) using our previously developed (& published) O-Net & {Theta}-Net model architectures. The model-generated images depict relatively close correlation with the ground truth images, implying that the O-Net & {Theta}-Net model architectures serve as viable frameworks for DNN model sculpting and training for both the purposes of image SR in optical microscopy as well as feature localization in these SR micrographs. We thus surmise on the potentiality of our proposed O-Net & {Theta}-Net DNN architectures for the development of models to be deployed in fully-automated image analysis pipelines in biomedical and healthcare diagnostics in the near future.

bioinformatics↗

{Theta}-Net: Achieving Enhanced Phase-Modulated Optical Nanoscopy in silico through a computational 'string of beads' architecture

We present herein a triplet string of concatenated O-Net ( bead) architectures (formulated as discussed in our previous study) which we term {Theta}-Net as a means of improving the viability of generated super-resolved (SR) images in silico. In the present study, we assess the quality of the afore-mentioned SR images with that obtained via other popular frameworks (such as ANNA-PALM, BSRGAN and 3D RCAN). Models developed from our proposed framework result in images which more closely approach the gold standard of the SEM-verified test sample as a means of resolution enhancement for optical microscopical imaging, unlike previous DNNs. In addition, cross-domain (transfer) learning was also utilized to enhance the capabilities of models trained on DIC datasets, where phasic variations are not as prominently manifested as amplitude/intensity differences in the individual pixels [unlike phase contrast microscopy (PCM)]. The present study thus demonstrates the viability of our current multi-paradigm architecture in attaining ultra-resolved images under poor signal-to-noise ratios, while eliminating the need for a priori PSF & OTF information. Due to the wide-scale use of optical microscopy for inspection & quality analysis in various industry sectors, the findings of this study would be anticipated to exhibit a far-ranging impact on several engineering fronts.

bioinformatics↗

Protective functions of ZO-2/Tjp2 expressed in hepatocytes and cholangiocytes against liver injury and cholestasis

BACKGROUND & AIMSTight junctions (TJs) establish tissue barriers that maintain osmotic homeostasis and, in the liver, isolate bile flow from the blood circulation. ZO-2/Tjp2 is a scaffold protein that tethers TJ transmembrane proteins to the actin cytoskeleton. Missense mutations in Tjp2 have recently been shown to cause progressive cholestatic liver disease in humans. However, the underlying mechanisms still remain elusive. To study the role of Tjp2 in cholestatic liver disease, we generated and characterized mice lacking Tjp2 in hepatocytes, cholangiocytes, or both. METHODSTjp2 was inactivated in the mouse liver (both in hepatocytes and cholangiocytes) or hepatocytes or cholangiocytes only. Liver function tests were carried out by biochemical analysis of plasma and liver samples and liver tissue was evaluated by immunohistochemistry and histology. The mice were also subjected to cholic acid (CA) diet to assess their susceptibility to liver insults. RESULTSDeletion of Tjp2 in the mouse liver did not result in apparent changes in TJ structure and composition, but lead to progressive cholestasis with lower expression levels of the bile acid (BA) transporter ABCB11/Bsep and the detoxification enzyme Cyp2b10. Feeding a CA diet that is well tolerated by control mice caused severe cholestasis and necrotic liver injury in mice lacking hepatic Tjp2. Administration of a CAR agonist, TCPOBOP, protected these mice from CA induced injury by enhancing the expression of the detoxifying enzyme Cyp2b10 in hepatocytes. Mice lacking Tjp2 in only hepatocytes or in only cholangiocytes showed less severe CA diet induced liver injury. CONCLUSIONLoss of Tjp2 from hepatocytes and cholangiocytes both contribute to progressive cholestatic liver disease and higher susceptibility to liver injury. In hepatocytes, Tjp2 exerts a protective role by regulating expression levels of BA transporters and detoxification enzymes. The mice may provide a new animal model for cholestatic liver disease linked to Tjp2 mutations in humans.

physiology↗