[Effects of litter thickness on natural regeneration of Larix principis-rupprechtii plantations]. / 枯落物厚度对华北落叶松人工林天然更新的影响.

In this study, we explored the thickness influence of undecomposed litter layer and semi-decomposed litter layer on the natural regeneration in an artificial pure forest of Larix principis-rupprechtii in the forest area of Guandi Mountain. We divided the litter into an undecomposed layer and a semi-decomposed layer, which was further divided into eight groups based on the thickness. The results showed that when the thickness of undecomposed layer was 0.32-0.83 cm, and that of semi-decomposed layer was 0.18-0.89 cm, the regeneration index was larger (≥0.15), and the regeneration was better. When the thickness of undecomposed layer was more than 1.1 cm and that of semi-decomposed layer was more than 0.5 cm, the regeneration index was smaller (≤0.07), and the rege-neration of understory was worse. Results of redundancy analysis showed that the undecomposed layer thickness of litter had a high and stable explanatory ability for natural regeneration, with a contribution rate of 38.7%, while the semi-decomposed layer thickness had no significant effect on natural regeneration. Structural equation modeling revealed that the thickness of undecomposed layer of litter increased the mechanical resistance to seed germination which had a negative direct effect on natural regeneration (-0.617), and a positive indirect effect on natural rege-neration by influencing the content of alkali-hydrolyzed nitrogen and available phosphorus (+0.178). The combined effects (-0.439) showed an inhibitory effect on the natural regeneration. In conclusion, the thickness of undecomposed layer of litter under L. principis-rupprechtii was most closely related to natural regeneration, and the thickness of semi-decomposed layer had a minimal effect on natural regeneration.

Natural chlorophyll: a review of analysis methods, health benefits, and stabilization strategies.

Chlorophyll (Chl) is a natural pigment, widely distributed ranging from photosynthetic prokaryotes to higher plants, with an annual yield of up to 1.2 billion tons worldwide. Five types of Chls are observed in nature, that can be distinguished and identified using spectroscopy and mass spectrometry. Chl is also used in the food industry owing to its bioactivities, including obesity prevention, inflammation reduction, viral infection inhibition, anticancer effects, anti-oxidation, and immunostimulatory properties. It has great potential of being applied as a colorant and dietary supplement in the food industry. However, Chl is unstable under various enzymatic, acidic, heat, and light conditions, which limit its application. Although some strategies, such as aggregation with other food components, microencapsulation, and metal cation replacement, have been proposed to overcome these limitations, they are still not enough to facilitate its widespread application. Therefore, stabilization strategies and bioactivities of Chl need to be expected to expand its application in various fields, thereby aiding in the sustainable development of mankind.

The relationship of MITF gene expression and promoter methylation with plumage colour in quail.

1. This study focused on the relationship between MITF mRNA expression and plumage colour in quail and the effect of promoter methylation on the expression of MITF mRNA.2. The CDS region of MITF mRNA was cloned by RT-PCR, followed by DNA sequencing. The RT-qPCR method was used to analyse the expression levels of MITF mRNA in dorsal skin tissue in Korean quail and Beijing white quail. The promoter region of the MITF gene was cloned, and the CpG island was predicted by the CpGplot program. The methylation levels of the CpG island were analysed using BS-PCR technology.3. Quail MITF mRNA contains a 1,476 bp complete ORF, which encodes a 492 amino acid residue protein. The MITF protein has no signal peptide or transmembrane region. The expression of MITF mRNA in dorsal tissue of Korean quail was significantly higher than that in Beijing white quail (p < 0.01). Abundant cis-elements and a 346 bp CpG island were found in the promoter region of the MITF gene. The average methylation level of the CpG island was 22 (22%) in Korean quail, and 46 (30%) in Beijing white quail (p < 0.05).4. The hypermethylation of the MITF gene promoter region in Beijing white quail resulted in a decrease in expression level, which was related to white feather colour.

The spatiotemporal epidemiological study on human brucellosis in shenyang, China from 2013 to 2022.

Background: Epidemiological characteristics of human brucellosis (HB) have changed over the last decade. In this study, we depicted the spatiotemporal features of HB in Shenyang, China, from 2013 to 2022 and the objective was to visualise spatiotemporal patterns and identify high-risk regions with the purpose to provide evidence for HB prevention and control. Methods: We performed an observational epidemiological study using HB data obtained from the National Notifiable Disease Reporting System (NNDRS). Joinpoint regression analysis was employed to determine the changing trends in the annual incidence. A vector boundary map of Shenyang was used to visualise spatial distribution. Spatial autocorrelation was identified using both global and local Moran's autocorrelation coefficients, while hotspot areas were determined using the Getis-Ord statistic. Results: A combined sum of 4103 HB cases were analysed, and the average level of annual incidence of HB was 5.52 per 100,000. The incidence of HB showed obvious seasonality, with a notable peak observed from April to July (summer peak). The annual incidence in Shenyang has been on the rise since 2013, with an annual percentage change (APC) of 6.39% (95%CI 1.29%, 12.39%). Xinmin County exhibited the most elevated average annual incidence rate, with Faku County ranking second. The average annual incidence in rural areas exhibited a significantly greater disparity compared to suburban areas (P < 0.001), whereas the incidence rate in suburban areas demonstrated a significantly higher contrast when compared to urban areas (P < 0.001). A clustered distribution of the annual incidence of HB was observed for all years from 2013 to 2022. Abnormally high values were found in suburban areas, and no abnormally high values were found after 2017. The low-low clustering areas were found in urban as well as suburban areas from 2013 to 2022. Hotspots (P < 0.05) were located in rural areas, while cold spots (P < 0.05) were found in both urban and suburban areas. Since 2020, there have been no hotspots in Shenyang. Conclusions: Rural areas are high-risk areas for HB and may be key to controlling HB epidemics. Although the annual incidence of HB in rural areas has increased, owing to the stability of spatial relationships and the disappearance of hotspots, there is little possibility of outbreaks; however, stricter monitoring should be applied in rural areas to prevent the emergence of new transmission routes.

Risk stratification by systemic manifestations secondary to hemodynamic disorders of patients with severe tricuspid regurgitation.

BACKGROUND: Tricuspid regurgitation (TR) is a prevalent disease that triggers systemic pathological changes including cardiac, respiratory, hepatic and digestive, hematopoietic, renal and skin issues. The burden of extra-cardiac manifestations has not been well described in TR patients and the clinical impact is unknown. METHODS: Patients with severe or more-than-severe TR during hospitalization, who did not have any previous cardiac procedures, hemodynamically significant congenital heart disease or concomitant severe aortic or mitral valve disease, were retrospectively analyzed. Pre-specified criteria and diagnosis of baseline characteristics were used to evaluate the presence of extra-cardiac manifestations secondary to TR after excluding comorbidities that may also lead to corresponding abnormalities. Extra-cardiac involvements encompass respiratory, hepatic and, digestive, renal, hematopoietic and dermatic system. Staging criteria are defined as no extra-cardiac system involvement in Stage 1, one in Stage 2, at least two extra-cardiac involvements in Stage 3 and any end-stage organ failure in Stage 4. A telephone follow-up was conducted to record the composite endpoint namely all-cause death or cardiac rehospitalization after the index hospitalization. RESULTS: A total of 258 patients were identified with a median age of 73 (interquartile range [IQR]: 62-83) years and 52.3% were female. Severe TR and more-than-severe TR patients accounted for 92.6% and 7.4% of the cohort. There were 20.5%, 27.5%, 37.6% and 14.3% of patients from Stage 1 to 4 respectively. The follow-up time was at a median of 251 (IQR: 183-324) days. TR Patients in Stage 3&4 were at an increased risk with borderline statistical significance to experience the composite endpoint compared to patients in Stage 1&2 (odds ratio [OR] 1.9, 95% confidence interval [CI] 1.0 to 3.7, P = 0.049). CONCLUSIONS: Approximately half of patients with at least severe TR presented with two or more extra-cardiac systemic manifestations, which may incur a 1.9-fold higher risk of all-cause death or cardiac rehospitalization than TR patients with one or less extra-cardiac involvement.

CGA alleviates LPS-induced inflammation and milk fat reduction in BMECs through the NF-κB signaling pathway.

Mastitis is an easy clinical disease in dairy cows, which seriously affects the milk yield and quality of dairy cows. Chlorogenic acid (CGA), a polyphenolic substance, is abundant in Eucommia ulmoides leaves and has anti-inflammatory and anti-oxidative stress effects. Here, we explore whether CGA attenuated lipopolysaccharide (LPS)-induced inflammation and decreased milk fat in bovine mammary epithelial cells (BMECs). 10 µg/mL LPS was used to induce mastitis in BMECs. QRT-PCR, Western blotting, oil red O staining, and triglyceride (TG) assay were used to examine the effects of CGA on BMECs, including inflammatory response, oxidative stress response, and milk fat synthesis. The results showed that CGA repaired LPS-induced inflammation in BMECs. The expression of IL-6, IL-8, TNF-α, IL-1ß, and iNOS was decreased, and the expression levels of CHOP, XCT, NRF2, and HO-1 were increased, which reduced the oxidative stress level of cells and alleviated the reduction of milk fat synthesis. In addition, the regulation of P65 phosphorylation by CGA suggests that CGA may exert its anti-inflammatory and anti-oxidative effects through the NF-κB signaling pathway. Our study showed that CGA attenuated LPS-induced inflammation and oxidative stress, and restored the decrease in milk fat content in BMECs by regulating the NF-κB signaling pathway.

Efficacy of COVID-19 vaccines in inflammatory bowel disease patients receiving anti-TNF therapy: A systematic review and meta-analysis.

Background and objectives: There are concerns about the serological responses to Coronavirus disease 2019 (COVID-19) vaccines in inflammatory bowel disease (IBD) patients, particularly those receiving anti-TNF therapy. This study aimed to systematically evaluate the efficacy of COVID-19 vaccines in IBD patients receiving anti-TNF therapy. Methods: Electronic databases were searched to identify relevant studies. We calculated pooled seroconversion rate after COVID-19 vaccination and subgroup analysis for vaccine types and different treatments were performed. Additionally, we estimated pooled rate of T cell response, neutralization response, and breakthrough infections in this population. Results: 32 studies were included in the meta-analysis. IBD patients receiving anti-TNF therapy had relatively high overall seroconversion rate after complete vaccination, with no statistical difference in antibody responses associated with different drug treatments. The pooled positivity rate of T cell response was 0.85 in IBD patients receiving anti-TNF therapy. Compared with healthy controls, the positivity of neutralization assays was significantly lower in IBD patients receiving anti-TNF therapy. The pooled rate of breakthrough infections in IBD patients receiving anti-TNF therapy was 0.04. Conclusions: COVID-19 vaccines have shown good efficacy in IBD patients receiving anti-TNF therapy. However, IBD patients receiving anti-TNF have a relatively high rate of breakthrough infections and a low level of neutralization response.

An ultrasensitive photo-driven self-powered aptasensor for microcystin-RR assay based on ZnIn2S4/Ti3C2 MXenes integrated with a matching capacitor for multiple signal amplification.

A photo-driven self-powered aptasensor was constructed based on a matching capacitor and the ZnIn2S4/Ti3C2 heterojunction as the photoanode and Cu2O as the photocathode in a dual-photoelectrode sensing matrix for multiple signal amplification for the ultrasensitive detection of microcystin-RR (MC-RR). The introduction of Ti3C2 MXene nanosheets on the photoanode surface can not only accelerate the transfer and separation of photoinduced electron/hole pairs, thus enhancing the output signal of the photo-driven self-powered system, but also provide a larger specific surface area for the immobilization of the bio-recognition unit aptamer. More importantly, for a portable and miniaturized device, a micro-workstation with the size of a universal serial bus (USB) disk and a novel short-circuit current access was proposed to capture the instantaneous output electrical signal for real-time data tracking. In such a way, a sensitivity of 2.7 mA pM-1 was achieved when the matching capacitor was integrated into the self-powered system, which was 22 times that without a capacitor. After the interaction between MC-RR and the corresponding aptamer, a 'signal-off' detection configuration was formed via the steric hindrance effect. Therefore, such a multiple signal amplification system realized the ultrasensitive and selective determination of MC-RR successfully. Under optimal conditions, the linear range of the self-powered aptasensor was 0.1 to 100 pM and the detection limit was 0.033 pM (S/N = 3). The aptasensor was applied to the detection of MC-RR in fish, exhibiting good reproducibility (≈3.88%), paving the way for detecting microcystins in real-life samples.

Imaging PIP2 and BCR microclusters in B cell immunological synapse.

The humoral immune response is dependent on B cell activation and differentiation, which is typically triggered by the formation of immunological synapses at the interface between B cells and the antigen presenting surfaces. However, due to the highly dynamic and transient feature of immunological synapses, it has been difficult to capture and investigate the molecular events that occur within them. The planar lipids bilayer (PLB) supported antigen presenting surface combined with high-resolution high-speed total internal reflection fluorescence microscope (TIRFM) live cell imaging system has been proved to be a powerful tool that allows us to visualize the dynamic events in immunological synapse. In addition, the phospholipid phosphatidylinositol-(4,5)-biphosphate (PIP2) plays a unique role in B cell activation, and it is difficult to investigate the synaptic dynamics of PIP2 molecules. Hence, we describe here the general procedures for the utilization of a PLB based antigen presenting system combining TIRFM based imaging methods to visualize the spatial-temporal co-distribution of PIP2 and BCR microcluster within the B cell immunological synapse.

WITHDRAWN: RNA binding protein Musashi2 regulates dairy cows' mastitis by activating the TGFß signaling pathway.

This article has been withdrawn at the request of the editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/policies/article-withdrawal.

Puerarin Alleviates H2O2-Induced Oxidative Stress and Blood-Milk Barrier Impairment in Dairy Cows.

During the perinatal period, the bovine mammary epithelial cells of dairy cows exhibit vigorous metabolism and produce large amounts of reactive oxygen species (ROS). The resulting redox balance disruption leads to oxidative stress, one of the main causes of mastitis. Puerarin (PUE) is a natural flavonoid in the root of PUE that has attracted extensive attention as a potential antioxidant. This study first investigated whether PUE could reduce oxidative damage and mastitis induced by hydrogen peroxide (H2O2) in bovine mammary epithelial cells in vitro and elucidated the molecular mechanism. In vitro, BMECs (Bovine mammary epithelial cells) were divided into four treatment groups: Control group (no treatment), H2O2 group (H2O2 stimulation), PUE + H2O2 group (H2O2 stimulation before PUE rescue) and PUE group (positive control). The growth of BMECs in each group was observed, and oxidative stress-related indices were detected. Fluorescence quantitative PCR (qRT-PCR) was used to detect the expression of tightly linked genes, antioxidant genes, and inflammatory factors. The expression of p65 protein was detected by Western blot. In vivo, twenty cows with an average age of 5 years having given birth three times were divided into the normal dairy cow group, normal dairy cow group fed PUE, mastitis dairy cow group fed PUE, and mastitis dairy cow group fed PUE (n = 5). The contents of TNF-α, IL-6, and IL-1ß in milk and serum were detected. In BMECs, the results showed that the PUE treatment increased the activities of glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), and total antioxidant capacity (T-AOC); ROS and malondialdehyde (MDA) levels were reduced. Thus, PUE alleviated H2O2-induced oxidative stress in vitro. In addition, the PUE treatment eliminated the inhibition of H2O2 on the expression of oxidation genes and tight junction genes, and the enrichment degree of NRF-2, HO-1, xCT, and tight junctions (claudin4, occludin, ZO-1 and symplekin) increased. The PUE treatment also inhibited the expression of NF-κB-associated inflammatory factors (IL-6 and IL-8) and the chemokine CCL5 in H2O2-induced BMECs. In vivo experiments also confirmed that feeding PUE can reduce the expression of inflammatory factors in the milk and serum of lactating dairy cows. In conclusion, PUE can effectively reduce the oxidative stress of bovine mammary epithelial cells, enhance the tight junctions between cells, and play an anti-inflammatory role. This study provides a theoretical basis for PUE prevention and treatment of mastitis and oxidative stress. The use of PUE should be considered as a feed additive in future dairy farming.

More simple, efficient and accurate food research promoted by intermolecular interaction approaches: A review.

The investigation of intermolecular interactions has become increasingly important in many studies, mainly by combining different analytical approaches to reveal the molecular mechanisms behind specific experimental phenomena. From spectroscopic analysis to sophisticated molecular simulation techniques like molecular docking, molecular dynamics (MD) simulation, and quantum chemical calculations (QCC), the mechanisms of intermolecular interactions are gradually being characterized more clearly and accurately, leading to revolutionary advances. This article aims to review the progression in the main techniques involving intermolecular interactions in food research and the corresponding experimental results. Finally, we discuss the significant impact that cutting-edge molecular simulation technologies may have on the future of conducting deeper exploration. Applications of molecular simulation technology may revolutionize the food research, making it possible to design new future foods with precise nutrition and desired properties.

Inhibitory effects of chlorophylls and its derivative on starch digestion in vitro.

Chlorophylls (Chls) have been shown to help regulate blood glucose levels. In this study, the effects of Chls and its derivative, pheophytin a (Phe a), on starch digestion in vitro were investigated. Chls significantly decreased starch hydrolysis while increasing resistant starch content (p < 0.05). SEM revealed that Chls either existed in free form or was absorbed and embedded on the surface of starch granules. Spectroscopic analysis and molecular docking demonstrated that Chls had a dual effect: (1) the phytol chain of Chls formed a double helix structure with starch, which may hinder the starch-enzyme contacts; and (2) the porphyrin ring of Chls interacted with amino acid residues of α-amylase and α-glucosidase to change the characteristics of enzymes, thereby inhibiting their activities. The investigation may serve as motivation for developing healthful starchy foods rich in Chls and enhancing the selection of foods for diabetics and hyperglycemias.

Protein C-Terminal Tyrosine Conjugation via Recyclable Immobilized BmTYR.

Protein modification plays an essential role in biological and pharmaceutical research. Due to the ordinary selectivity and inevitable damage to proteins of chemical synthetic methods, increased efforts were focused on biocatalysts which exhibited high regioselectivity and mild reaction conditions. However, separation of the biocatalysts and modified proteins remained a problem, especially when scaling up. Here, we developed a simple method for site-specific protein modification with a recyclable biocatalyst. The immobilizing tyrosinase (BmTYR) on magnetic beads can oxidize C-terminal tyrosine residues of the target protein to o-quinone, followed by the spontaneous addition of different nucleophiles (e.g., aniline derivatives), resulting in a C-terminal modified protein. Compared to the homogeneous biocatalytic system reported before, this heterogeneous system leads to an easier separation. Furthermore, the solid-phase biocatalyst can be regenerated during separation, providing reusability and lower costs.

Correlation analysis between characteristics under gastroscope and image information of tongue in patients with chronic gastriti.

OBJECTIVE: To explore the correlation between diagnostic information of tongue and gastroscopy results of patients with chronic gastritis. METHODS: Frequent pattern growth (FP-Growth), SPSS Modeler was used to analyze the correlation rules between the image information of tongue parameters and the characteristics of the stomach and duodenum seen under gastroscopy. RESULTS: Ranking in order of confidence: cyanotic tongue, slippery fur, yellow fur and spotted tongue were sequently associated with both gastric antrum mucosal hyperemia or edema and gastric antrum mucosal erythema/macula. L, one value of tongue coating color, which counted among (30, 60), tooth-marked tongue and b, one value of tongue coating color, which counted in the range of (5, 20) were sequently associated with gastric antrum mucosal erythema /macula. A, one value of tongue body color, which counted in the range of (0, 20), was related to both gastric antrum mucosal hyperemia or edema and gastric antrum mucosal erythema /macula. a, one value of tongue coating color, which counted in the range of (15, 35), was associated with gastric antrum mucosal erythema / macula. There are a total of 9 strong correlation rules. CONCLUSIONS: Cyanotic tongue, slippery fur, yellow fur, the CIE Lab value of tongue coating, a, the value of tongue body color, spotted tongue, and tooth-marked tongue are all related to the gastric antrum mucosal hyperemia or edema and gastric antrum mucosal erythema / macula. The conditions of gastric mucosa could be predicted by the examination of the above related image information of tongue.

Tensor-based basis function learning for three-dimensional sound speed fields.

Basis function learning is the stepping stone towards effective three-dimensional (3D) sound speed field (SSF) inversion for various acoustic signal processing tasks, including ocean acoustic tomography, underwater target localization/tracking, and underwater communications. Classical basis functions include the empirical orthogonal functions (EOFs), Fourier basis functions, and their combinations. The unsupervised machine learning method, e.g., the K-singular value decomposition (K-SVD) algorithm, has recently tapped into the basis function design, showing better representation performance than the EOFs. However, existing methods do not consider basis function learning approaches that treat 3D SSF data as a third-order tensor, and, thus, cannot fully utilize the 3D interactions/correlations therein. To circumvent such a drawback, basis function learning is linked to tensor decomposition in this paper, which is the primary drive for recent multi-dimensional data mining. In particular, a tensor-based basis function learning framework is proposed, which can include the classical basis functions (using EOFs and/or Fourier basis functions) as its special cases. This provides a unified tensor perspective for understanding and representing 3D SSFs. Numerical results using the South China Sea 3D SSF data have demonstrated the excellent performance of the tensor-based basis functions.

Facile Azabenz-Annulations through UV-induced Photocyclization: A Promising Method for Perylenediimide-Based Organic Semiconductors.

The derivatization of perylenediimides (PDIs) by bay decoration is essential for the development of PDI-based semiconductors owing to their excellent photoelectric properties. Herein, four bis-azabenz-annulated PDIs (bis-AzaBPDIs) are concisely synthesized in high yields through ultraviolet-induced photocyclization, where the reaction processes including aldimine condensation, cyclization, and oxidative re-aromatization are investigated. The optical characterizations and theoretical simulation reveal that the unique properties of the four bis-AzaBPDIs are comparable to their parent PDI. Organic field effect transistors with compounds 2, 3, or 4 as active layers indicated that all compounds showed unipolar electron transport properties with the mobilities of 1.1×10-3 , 5.8×10-4 , and 8.5×10-6  cm2  V-1 s-1 , respectively. These results suggest the great potential of bis-AzaBPDIs as organic semiconductors. The easy preparation approach reported in this work would renew research interest in developing bis-AzaBPDI-based optoelectronic molecules.

Analysis of ferroptosis-associated genes in Crohn's disease based on bioinformatics.

Background: Ferroptosis, a novel mode of apoptosis has recently been shown to be associated with fibrosis, tumor, cardiovascular, and other diseases. In this study, using bioinformatic analysis, we identified ferroptosis genes associated with Crohn's disease (CD) and performed biological function analysis, identified potential drug targets, and provided new directions for the future treatment of CD. Methods: Differential expression analysis was performed using the GSE186582 dataset from the Gene Expression Omnibus (GEO) database. Ferroptosis-associated genes were downloaded from the FerrDB database, and overlapping genes associated with CD and ferroptosis were extracted. Then, we performed functional enrichment analysis, constructed a protein-protein interaction network (PPI), identified the correlation between hub genes and immune infiltration, performed external validation using a second and third dataset (GSE102133, GSE95095), and identified potential therapeutic agents. Finally, we validated the protein expression levels of the identified hub genes by immunohistochemical staining in the colon tissues from CD and healthy participants. Results: A total of 28 ferroptosis-associated genes associated with CD were identified in our analysis, which included 22 up-regulated and 6 down-regulated genes. Gene Ontology (GO) analysis showed that these genes are essential for the apical plasma membrane and amide transport, and Metascape analysis showed that these genes mainly act on IL-4 and IL-13 signaling pathways. Five hub genes, PTGS2, IL6, IL1B, NOS2, and IDO1, were identified by a protein interaction network, and external validation of these hub genes showed statistically significant differences in expression between the CD patients and normal participants (p < 0.05), and all AUC values were greater than 0.8. Further, we predicted the top 10 drugs used to treat CD. Immune infiltration results suggest that Hub gene is related to T cells, macrophages, dendritic cells, and other immune cells. Finally, the results of immunohistochemical experiments showed that the protein expression of the hub gene was higher in CD colon tissue than in normal subjects (p < 0.05). Conclusion: Bioinformatics analysis showed that ferroptosis is closely related to the development of CD, and the prediction of potential drugs provides new targets for the treatment of CD. Moreover, five hub genes identified are potentially new and effective markers for the diagnosis of CD.

Porcine RIG-I and MDA5 Signaling CARD Domains Exert Similar Antiviral Function Against Different Viruses.

The RIG-I-like receptors (RLRs) RIG-I and MDA5 play critical roles in sensing and fighting viral infections. Although RIG-I and MDA5 have similar molecular structures, these two receptors have distinct features during activation. Further, the signaling domains of the N terminal CARD domains (CARDs) in RIG-I and MDA5 share poor similarity. Therefore, we wonder whether the CARDs of RIG-I and MDA5 play similar roles in signaling and antiviral function. Here we expressed porcine RIG-I and MDA5 CARDs in 293T cells and porcine alveolar macrophages and found that MDA5 CARDs exhibit higher expression and stronger signaling activity than RIG-I CARDs. Nevertheless, both RIG-I and MDA5 CARDs exert comparable antiviral function against several viruses. Transcriptome analysis showed that MDA5 CARDs are more effective in regulating downstream genes. However, in the presence of virus, both RIG-I and MDA5 CARDs exhibit similar effects on downstream gene transcriptions, reflecting their antiviral function.

Analysis of Porcine RIG-I Like Receptors Revealed the Positive Regulation of RIG-I and MDA5 by LGP2.

The RLRs play critical roles in sensing and fighting viral infections especially RNA virus infections. Despite the extensive studies on RLRs in humans and mice, there is a lack of systemic investigation of livestock animal RLRs. In this study, we characterized the porcine RLR members RIG-I, MDA5 and LGP2. Compared with their human counterparts, porcine RIG-I and MDA5 exhibited similar signaling activity to distinct dsRNA and viruses, via similar and cooperative recognitions. Porcine LGP2, without signaling activity, was found to positively regulate porcine RIG-I and MDA5 in transfected porcine alveolar macrophages (PAMs), gene knockout PAMs and PK-15 cells. Mechanistically, LGP2 interacts with RIG-I and MDA5 upon cell activation, and promotes the binding of dsRNA ligand by MDA5 as well as RIG-I. Accordingly, porcine LGP2 exerted broad antiviral functions. Intriguingly, we found that porcine LGP2 mutants with defects in ATPase and/or dsRNA binding present constitutive activity which are likely through RIG-I and MDA5. Our work provided significant insights into porcine innate immunity, species specificity and immune biology.