cGAS is a cytosolic DNA sensor that activates innate immune responses through production of the second messenger 2’3’-cGAMP, which activates the adaptor STING. cGAS senses dsDNA in a length-dependent but sequence-independent manner, and it cannot discriminate self-DNA from foreign DNA. In normal physiological conditions, cellular DNA is sequestered in the nucleus by nuclear envelope and in mitochondria by mitochondrial membrane. When self-DNA leaks into the cytosol during cellular stress, or during mitosis, the cGAS can be exposed to self-DNA and be activated. Recently, many studies have investigated how cGAS keeps inactive and avoids to be aberrantly activated by self-DNA. Thus, the aim of this narrative review is to summarize the mechanisms by which cGAS avoids to sense self-DNA under normal physiological conditions.

African swine fever virus (ASFV) is a large double stranded DNA arbovirus that is highly contagious and seriously endangers the lives of domestic and wild pigs. In the past decade, African swine fever (ASF) has spread in many countries in the Caucasus, Russian Federation, Eastern Europe and Asia, causing significant losses to the pig industry. At present, there is a lack of effective vaccine and treatment for ASF. Therefore, the rapid and accurate detection is crucial for ASF prevention and control. In this study, we have developed a portable lateral flow strip (LFS) detection method mediated by recombinase polymerase amplification (RPA) and DNA enzyme (LwCas13a), which is performed at 37 ℃ and visualized by eyes without the need for complex instruments. This RPA-LwCas13a-LFS is based on the ASFV structural protein p17 gene (D117L), with a detection sensitivity up to 2 gene copies. This method is highly specific and has no cross reactivity to 7 other pig viruses. In the detection of 33 clinical samples, the p17 (D117L) RPA-LwCas13a-LFS had 100% coincidence with conventional quantitative PCR (qPCR). These findings demonstrate the potential of this simple, rapid, sensitive, and specific ASFV detection method for on-site ASFV detection.

Porcine epidemic diarrhea virus (PEDV) has caused great damage to the global pig industry. The innate immunity plays a significant role in resisting viral infection, however, the exact role of innate immunity in the anti-PEDV response has not been fully elucidated. In this study, we observed that various porcine innate immune signaling adaptors are involved in the anti-PEDV activity. Among these, TRIF and MAVS showed the strongest anti-PEDV activity. The endogenous TRIF, MAVS and STING were selected for further examination of anti-PEDV activity. Agonist stimulation experiments showed that TRIF, MAVS and STING signaling all have obvious anti-PEDV activity. The siRNA knockdown assay showed that TRIF, MAVS and STING are also all involved in anti-PEDV response, and their remarkable effects on PEDV replication were confirmed in TRIF-/-, MAVS-/- and STING-/- Vero cells. For further verification, the anti-PEDV activity of TRIF, MAVS and STING could be reproduced in porcine IPEC-DQ cells. In summary, this study reveals that multiple pattern recognition receptor (PRR) signaling pathways of porcine innate immunity play an important role in the anti-PEDV infection, providing new and useful antiviral knowledge for prevention and control of PEDV spreading.

Bovine respiratory disease is still a major concern in feedlots and has major economic impact. Another consequence of respiratory infections is the use of antimicrobial molecules to control bacterial pathogens. This can participate to the emergence and shedding of antimicrobial re-sistance that can threaten animal as well as human health. Appeasing pheromones with their capacity to reduce stress and thus their ability to preserve the functions of the immune system have been proposed to reduce the use of antimicrobial substances. In the current report we as-sessed the effect of appeasing pheromone administration on bovine health and performance during the fattening period. Zootechnical and health parameters as well as whole blood immune transcript expressions were measured over weeks in young bulls to determine the effect of the pheromone. We observed a reduction of clinical signs at day 30 in young bulls who received the pheromone and a higher expression of interleukin 8 transcripts in this group than in the control group. Our results are in line with previous reports in bovine and other mammals and ask for further studies to shed more light on the beneficial impact of appeasing pheromones and to de-cipher their exact mechanisms of action.

The innate immune system is the first line of host defense sensing viral infection. Manganese (Mn) has recently been found to be involved in the activation of innate immune DNA sensing cGAS-STING pathway and subsequent anti-DNA virus function. However, whether Mn2+ mediates host defense against RNA viruses is still unclear. In the current study, we demonstrated that Mn2+ exhibited antiviral effects against various animal and human viruses including RNA viruses such as PRRSVs and the VSV as well as a DNA virus such as the HSV1 in a dose-dependent manner. Moreover, cGAS and STING were both investigated in the Mn2+ mediated antiviral roles using the knockout cells made by CRISPR-Cas9 approach. Unexpectedly, the results revealed that neither cGAS knockout nor STING knockout had any effect on Mn2+ mediated antiviral functions. Nevertheless, we verified that Mn2+ promoted the activation of cGAS-STING signaling pathway. These findings suggest that Mn2+ has broad spectrum antiviral activities in a cGAS-STING pathway independent manner. This study also provides significant insights into redundant mechanisms participating in the Mn2+ antiviral functions and also indicates new target for Mn2+ antiviral therapeutics.