CD163-Knockout Pig Stem Cells Open New Door to Fighting PRRSV
Scientists engineer gene-edited porcine iPSCs lacking the PRRSV entry receptor, creating a powerful model for studying viral infection mechanisms.
Summary
Researchers at Northwest A&F University successfully generated CD163-knockout porcine induced pluripotent stem cells (iPSCs) by reprogramming ear fibroblasts from gene-edited pigs lacking the CD163 receptor — the primary gateway for Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) infection. Using a Tet-On lentiviral OSKM system, the team confirmed robust pluripotency via alkaline phosphatase staining, PCR, immunofluorescence, and RNA sequencing. The resulting cell line expressed key pluripotency markers (NANOG, SALL4, OCT4, ESRRB), downregulated somatic markers, and demonstrated multilineage differentiation capacity. This genetically defined, virus-resistant iPSC platform offers a valuable in vitro tool for dissecting PRRSV-host interactions and accelerating antiviral therapeutic development for a pathogen causing major global livestock losses.
Detailed Summary
Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) is one of the most economically devastating swine pathogens worldwide, responsible for significant reproductive failure and respiratory disease in pigs. CD163, a scavenger receptor expressed on macrophages, is the critical entry point for PRRSV, making it a prime genetic target for disease resistance strategies. Understanding exactly how the virus exploits this receptor requires sophisticated, genetically controlled cell models.
In this study, researchers reprogrammed porcine auricular marginal fibroblasts (PAMFs) isolated from previously established CD163-knockout transgenic pigs into induced pluripotent stem cells (iPSCs). They employed porcine-derived OSKM factors (OCT4, SOX2, KLF4, c-MYC) delivered via a Tet-On lentiviral system combined with an LBCSV reprogramming protocol — a methodologically rigorous approach to achieving stable reprogramming in a notoriously difficult species.
The resulting CD163-KO iPSC line demonstrated strong hallmarks of pluripotency: alkaline phosphatase positivity, upregulated NANOG and SALL4 at both mRNA and protein levels, downregulated somatic marker THY1, and RNA-seq confirmation of pluripotency gene activation alongside suppression of developmental genes. The cells also showed enhanced basal metabolic activity compared to porcine embryonic fibroblasts, consistent with metabolic reprogramming seen in true iPSCs.
Functional validation through embryoid body formation and primordial germ cell-like cell induction confirmed genuine multilineage differentiation potential and gene editing compatibility — qualities essential for downstream mechanistic studies.
This platform provides a powerful, reproducible in vitro system to study PRRSV infection biology, screen antiviral compounds, and potentially support the development of disease-resistant pig breeds. Caveats include the porcine-specific scope and the early-stage nature of the cell line's functional characterization.
Key Findings
- CD163-KO porcine iPSCs were successfully generated from transgenic pig fibroblasts using OSKM lentiviral reprogramming.
- Cells confirmed pluripotent via alkaline phosphatase staining, NANOG/SALL4 upregulation, and RNA-seq analysis.
- RNA-seq showed significant upregulation of pluripotency genes (OCT4, ESRRB) versus porcine embryonic fibroblasts.
- Embryoid body and primordial germ cell induction confirmed multilineage differentiation and gene editing compatibility.
- Platform enables in vitro investigation of PRRSV entry mechanisms without live virus infection risk.
Methodology
CD163-KO porcine auricular fibroblasts were reprogrammed using porcine OSKM factors via a Tet-On lentiviral system with LBCSV protocol. Pluripotency was validated by alkaline phosphatase staining, qPCR, semi-qPCR, immunofluorescence, Western blot, and RNA sequencing. Differentiation potential was assessed via embryoid body formation and primordial germ cell-like cell induction.
Study Limitations
This study is limited to porcine biology and does not directly translate to human applications. The iPSC line's long-term stability, full differentiation fidelity into alveolar macrophages (the natural PRRSV target), and PRRSV challenge validation are not yet reported. Findings require further in vivo confirmation.
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