The cell’s capacity to integrate and respond to spatial information is a crucial feature of morphogenesis and development. The Planar Cell Polarity (PCP) pathway is a signaling mechanism, widely conserved across metazoans, providing spatial orientation along the plane of an epithelium in morphogenic processes ranging from insect wing patterning to mammalian cochleae. Although the core genes involved in the PCP pathway have been molecularly identified in the 1990s, the PCP signaling mechanism remains controversial. In this article I discuss the main players and previous models of PCP signaling reported in the literature, and propose a new model. According to it PCP is established through an homophobic signal by transmembrane protein Frizzled (Fz): 1) a Fz signal in one cell repeals Fz itself in the adjacent cell, thereby generating symmetry breaking; 2) the instructive PCP signal is conveyed through Fz interaction with atypical cadherin Flamingo (Fmi). More broadly, homophobic signaling may represent a novel mechanism for cell-cell signaling of spatial information through modulation of cell adhesion rather than canonical ligand-receptor binding.

2-(4-Benzyloxy-3-methoxyphenyl)-5-(carbethoxyethylene)-7-methoxy-benzofuran (BMBF), a benzofuran derivative, is an intermediate found in the process of total synthesis of ailanthoidol. Benzofuran derivatives are a class of compounds that possess various biological and pharmacological activities. The present study explored the anti-metastasis effects in hepatocellular carcinoma (HCC). Our preliminary findings indicate that BMBF suppresses the proliferation and changes the morphology of Huh7, an HCC cell line with a mutated p53 gene (Y220C). According to scratching motility assay, noncytotoxic concentrations of BMBF significantly inhibited the motility and migration in Huh7 cells. BMBF upregulated the expression of E-cadherin and downregulated the expression of vimentin, Slug, and MMP9, which are associated with epithelial-mesenchymal-transition (EMT) and metastasis in Huh7 cells. BMBF decreased the expression of integrin α7 and deactivated its downstream signal FAK/AKT and inhibited p53 protein levels. Cell transfection with p53 siRNA resulted in prevention of cell invasion because of the reduced expression of integrin α7, Slug, and MMP-9 in Huh7 cells. BMBF had anti-metastatic effects in PLC/PRF/5, an HCC cell line with R249S, a mutated p53 gene. Our findings indicate that BMBF has anti-metastatic effects in that it downregulates p53 and mediates the suppression of integrin α7, EMT, and MMP-9 in HCC cells with mutated p53 gene.

Our prior studies have shown that B type Natriuretic Peptide (BNP) decreases absorption from the gastrointestinal (GI) tract. Since non-muscle myosin-type II (NMM-II) is known to have a role in epithelial tight junction regulation, we aimed to test whether BNP has an effect on the localization and expression of NMM-II in the intestinal villi. We treated wild type mice with a 10 ng/g intravenous bolus of BNP followed by infusion of BNP at 1ng/g/minute vs. vehicle control. The mice were then euthanized and intestinal tissue isolated and sectioned. The tissue was immune-stained for NMM-II and examined using fluorescence microscopy. The tissue section not treated with antibody to NMM-II was used as a methodological control to evaluate the non-specific binding. Scanning electron micrographic images were taken to compare structural differences between the two groups. Western blotting was performed to compare the regional protein expression of NMM-II and associated proteins including smooth muscle actin, kinesin, and E cadherin in small intestinal tissue between BNP vs. vehicle infused mice. Fluorescence microscopy revealed markedly increased localization of NMM-II at the crypts and core of intestinal villi of the jejunum, ileum and colon of BNP treated mice compared to vehicle. Transmission electron microscopy revealed that the microvilli of BNP treated mice assumed the distinctive appearance of ‘relaxed’ microvilli compared to vehicle. Such decrease in contractility was previously shown to decrease para-cellular permeability of epithelia. Our observation indicates that BNP alters the localization of NMM-II in intestinal villi and makes the intestinal villi structures assume a state of decreased permeability of the apical junctional complex. Further characterization of this process and understanding the specific mediators involved could lead to the identification of novel therapeutic targets for various disease states such as heart failure and malabsorption.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), an RNA virus, is responsible for coronavirus disease 2019 (COVID-19) pandemic of 2020. Experimental evidence suggests that microRNA can mediate an intracellular defence mechanism against some RNA viruses. The purpose of this study was to identify microRNA with predicted binding sites in the SARS-CoV-2 genome, compare these to their microRNA expression profiles in lung epithelial tissue and make inference towards possible roles for microRNA in mitigating coronavirus infection. We hypothesize that high expression of specific coronavirus-targeting microRNA in lung epithelia may protect against infection and viral propagation, conversely low expression may confer susceptibility to infection. We have identified 128 human microRNA with potential to target the SARS-CoV-2 genome, most of which have very low expression in lung epithelia. Six of these 128 microRNA are differentially expressed upon in vitro infection of SARS-CoV-2. Twenty-eight and 23 microRNA also target the SARS-CoV and MERS-CoV, respectively. In addition, 48 and 32 microRNA are commonly identified in two other studies. Further research into identifying bona fide coronavirus targeting microRNA will be useful in understanding the importance of microRNA as cellular defence mechanism against pathogenic coronavirus infections.