Xiaochuan Tang

Fatty liver hemorrhagic syndrome (FLHS) is a common metabolic disorder in laying hens that severely impacts the poultry industry by reducing egg production and causing sudden mortality. To investigate the genetic factors underlying fatty liver development in chickens, we generated transgenic chimeric chickens by adenoviral injection into embryos and induced angiopoietin-like 3 (ANGPTL3) overexpression using a Tet-On system. The role of ANGPTL3 in the pathogenesis of FLHS was subsequently examined. Our results demonstrated that ANGPTL3 overexpression markedly increased liver weight and lipid deposition, aggravated oxidative stress and inflammatory responses, and altered the expression of lipid metabolism–related genes. These findings highlight a pivotal role of ANGPTL3 in the development of fatty liver in chickens and provide new insights into the molecular mechanisms underlying FLHS, offering potential targets for prevention and therapeutic intervention.

Increasingly complex epidemics of animal infectious diseases have emerged as a major risk to livestock production and human health. However, current detection methods for animal infectious diseases suffer from shortcomings such as insufficient sensitivity, complicated operation, and reliance on skilled personnel, highlighting the urgent need for novel sensing platforms. CRISPR/Cas systems are adaptive immune systems found in many prokaryotes. Owing to their ability to precisely and reliably target and cleave nucleic acids, the CRISPR/Cas-based nucleic acid detection technology is considered a promising new detection method. When leveraged with a pre-amplification step and established readout methods, CRISPR/Cas-based sensing platforms can achieve a high sensitivity of single-base resolution or attomolar levels on-site. In this review, we first outline the history, working principles, and nucleic acid detection platforms derived from various CRISPR/Cas systems. Next, we evaluate the advantages and limitations of different nucleic acid pre-amplification methods integrated with CRISPR/Cas systems, followed by a discussion of readout methods employed in CRISPR/Cas-based sensing platforms. Additionally, we highlight recent applications of CRISPR/Cas-based sensing platforms in identifying animal infectious diseases. Finally, we address the challenges and prospects of CRISPR/Cas-based sensing platforms for the early and accurate diagnosis of animal infectious diseases.

In this study, efficient knock-in (KI) of human epidermal growth factor (hEGF) cDNA at the ovalbumin (OV) locus in cultured chicken cells was achieved using adenovirus as a delivery for CRISPR/Cas9 elements and optimizing donor vector construction. The strategy of recruiting donor DNA to the insertion site further improved the KI efficiency. The inserted hEGF cDNA can expressed in primary oviduct cells and secreted hEGF promoted proliferation of Hela cells. Moreover, we achieved efficient KI in blastoderm cells without altering their induction in vitro and obtained germline chimeric KI chicken embryos by transplanting KI blastoderm cells as well as injecting adenovirus directly, in vivo. Our results provided an efficient KI method for chicken cells and embryos, and lay the foundation for more convenient production of KI chicken at the OV locus, which will promote the development of oviduct-specific bioreactor.

Producing transgenic chickens with chicken blastodermal cells (cBCs) is inefficient due to the extremely low germline transmission capacity of cBCs. As chicken primordial germ cells (PGCs) have been reported as an efficient method for producing transgenic chickens, the inefficiency of cBCs could potentially be resolved by inducing them to differentiate into germ cells. However, whether chemical inducers are able to enhance cBCs germline competence in vitro is unknown and the molecular mechanisms of differentiation of chicken pluripotent cells into germ cells are poorly understood. We cultured cBCs with a monolayer morphology in E8 medium, a xeno- and feeder-free medium. We showed that retinoic acid (RA) treatment increased expression of germ cell-specific genes in cBCs. Using western blot, we determined that RA stimulated Smad1/5 phosphorylation. Moreover, Smad1/5 activation regulates the expression of germ cell-specific genes, as co-treatment with a Smad1/5 phosphorylation inhibitor or activator alters expression of these genes. We also demonstrate that Smad1/5 is required for RA-induced differentiation by RNA interference knockdown. Our results demonstrated that E8 medium is able to maintain cBC growth for weeks and RA treatment induced germ cell differentiation of cBCs through the BMP-Smad1/5 signaling pathway.