Discovery of Zika virus host dependency factors in trophoblasts using CRISPR/Cas9 screening

Emerging mosquito-borne RNA viruses cause massive health complications worldwide. The Zika virus (ZIKV), in particular, has spread dramatically since 2007 and has provoked epidemics in the Americas and the South Pacific. The lack of antiviral therapy and vaccination has focused research on the investigation of ZIKV-host interactions, in order to understand underlying molecular infection mechanisms. We have established an approach for the analysis of ZIKV host dependency factors in a human trophoblast cell line and applied genome-wide CRISPR/Cas9 knockout mutagenesis. The presented method is especially of value for the identification of factors that are essential for placental infection with the potential to serve as targets for antiviral treatment.

Cardioprotection by placenta-derived stromal cells in a murine myocardial infarction model

BACKGROUND

Autologous cells for cell therapy of ischemic cardiomyopathy often display age- and disease-related functional impairment, whereas an allogenic immunotolerant cell product would allow off-the-shelf application of uncompromised donor cells. We investigated the cardiac regeneration potential of a novel, clinical-grade placenta-derived human stromal cell product (PLX-PAD).

METHODS

PLX-PAD cells derived from human donor placentas and expanded in a three-dimensional bioreactor system were tested for surface marker expression, proangiogenic, anti-inflammatory, and immunomodulatory properties in vitro. In BALB/C mice, the left anterior descending artery was ligated and PLX-PAD cells (n = 10) or vehicle (n = 10) were injected in the infarct border zone. Four weeks later, heart function was analyzed by two-dimensional and M-mode echocardiography. Scar size, microvessel density, extracellular matrix composition, myocyte apoptosis, and PLX-PAD cell retention were studied by histology.

RESULTS

In vitro, PLX-PAD cells displayed both proangiogenesis and anti-inflammatory properties, represented by the secretion of both vascular endothelial growth factor and angiopoietin-1 that was upregulated by hypoxia, as well as by the capacity to suppress T-cell proliferation and augment IL-10 secretion when co-cultured with peripheral blood mononuclear cells. Compared with control mice, PLX-PAD-treated hearts had better contractile function, smaller infarct size, greater regional left ventricular wall thickness, and less apoptosis after 4 wk. PLX-PAD stimulated both angiogenesis and arteriogenesis in the infarct border zone, and periostin expression was upregulated in PLX-PAD-treated hearts.

CONCLUSIONS

Clinical-grade PLX-PAD cells exert beneficial effects on ischemic myocardium that are associated with improved contractile function, and may be suitable for further evaluation aiming at clinical pilot trials of cardiac cell therapy.