DHA and EPA inhibit porcine coronavirus replication by alleviating ER stress.

IMPORTANCE: Porcine epidemic diarrhea caused by porcine coronaviruses remains a major threat to the global swine industry. Fatty acids are extensively involved in the whole life of the virus. In this study, we found that docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) significantly reduced the viral load of porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis virus (TGEV), and porcine delta coronavirus (PDCoV) and acted on the replication of the viruses rather than attachment and entry. We further confirmed that DHA and EPA inhibited PEDV replication by alleviating the endoplasmic reticulum stress. Meanwhile, DHA and EPA alleviate PEDV-induced inflammation and reactive oxygen species (ROS) levels and enhance the cellular antioxidant capacity. These data indicate that DHA and EPA have antiviral effects on porcine coronaviruses and provide a molecular basis for the development of new fatty acid-based therapies to control porcine coronavirus infection and transmission.

Salmonella Infection Causes Hyperglycemia for Decreased GLP-1 Content by Enteroendocrine L Cells Pyroptosis in Pigs.

Inflammatory responses have been shown to induce hyperglycemia, yet the underlying mechanism is still largely unclear. GLP-1 is an important intestinal hormone for regulating glucose homeostasis; however, few studies have investigated the influence of digestive tract Salmonella infection on enteroendocrine L cell secretions. In this study, we established a model of Salmonella-infected piglets by oral gavage in order to analyze the effects of Salmonella infection on enteroendocrine L cell function. Furthermore, in vitro lipopolysaccharide (LPS) was administered to STC-1 cells to clarify its direct effect on GLP-1 secretion. The results showed that significantly increased blood glucose in the group of Salmonella-infected piglets was observed, and Salmonella infection decreased blood GLP-1 content. Then, ileal epithelium damage was observed by histological detection, and this was further verified by TUNEL staining. We identified activation of TLR signaling demonstrating up-regulated expressions of TLR4 and nuclear factor-kappa B (NF-ΚB). Furthermore, it was shown that Salmonella induced pyroptosis of enteroendocrine L cells and enhanced the secretion of IL-1ß through augmenting gene and protein expressions of NOD-like receptor protein 3 (NLRP3), apoptosis-associated speck-like protein containing a carboxyl-terminal CARD (ASC), Caspase 1, and gasdermin D (GSDMD). Meanwhile, in vitro LPS treatment induced the pyroptosis of STC-1 cells and reduced the secretion of GLP-1. Altogether, the results demonstrated that Salmonella infection can reduce secretion of GLP-1 by inducing pyroptosis of intestinal L cells, which may eventually result in hyperglycemia. The results provided evidence for the cause of hyperglycemia induced by inflammation and shed new light on glucose homeostasis regulation.

5-HEPE reduces obesity and insulin resistance by promoting adipose tissue browning through GPR119/AMPK/PGC1α activation.

AIMS: Activating thermogenic program in brown adipocytes serves as a potential therapeutic target for increasing energy expenditure during the treatment of metabolic diseases. 5(S)-hydroxy-eicosapentaenoic acid (5-HEPE), an omega-3 unsaturated fatty acid metabolite, has been shown to enhance insulin secretion in vitro. However, its role in modulating obesity-related diseases remains largely unclear. MAIN METHODS: To investigate this further, mice were fed with a high-fat diet for 12 weeks and then injected intraperitoneally every other day with 5-HEPE for 4 additional weeks. KEY FINDINGS: In vivo, our results demonstrated that 5-HEPE alleviated the HFD-induced obesity and insulin resistance, leading to a significant decrease in subcutaneous fat and epididymal fat index and an increase in brown fat index. Compared to the HFD group, the 5-HEPE group mice had lower ITT and GTT AUC and lower HOMA-IR. Moreover, 5HEPE effectively increased energy expenditure of mice. 5-HEPE also significantly promoted brown adipose tissue (BAT) activation and browning in white adipose tissue (WAT) by up-regulating genes and proteins expression of UCP1, Prdm16, Cidea, and PGC1α. In vitro, we found 5-HEPE significantly promoted 3T3-L1 browning. Mechanistically, 5-HEPE acts by activating the GPR119/AMPK/PGC1α pathway. In conclusion, this study emphasizes a critical role of 5-HEPE in improving body energy metabolism and adipose tissue browning in HFD-fed mice. SIGNIFICANCE: Our results suggest that 5-HEPE intervention may be an effective target for preventing obesity-related metabolic diseases.

GPAT3 regulates the synthesis of lipid intermediate LPA and exacerbates Kupffer cell inflammation mediated by the ERK signaling pathway.

In the process of inflammatory activation, macrophages exhibit lipid metabolism disorders and accumulate lipid droplets. Kupffer cells (KCs) are the resident hepatic macrophage with critical defense functions in the pathogenesis of several types of liver disease. How dysregulated lipid metabolism contributes to perturbed KCs functions remains elusive. Here we report that glycerol-3-phosphate acyltransferase 3 (GPAT3) plays a key role in KCs inflammation response. Our findings indicate that lipopolysaccharide (LPS)-mediated inflammatory activation markedly increased lipid droplets (LDs) accumulation in KCs. This increase could be attributed to significantly up-regulated GPAT3. The loss of GPAT3 function obviously reduced KCs inflammation reaction both in vivo and in vitro, and was accompanied by improved mitochondrial function and decreased production of lysophosphatidic acid (LPA), in turn inhibiting extracellular regulated protein kinases (ERK) signaling pathway. Overall, this study highlights the role of GPAT3 in inflammatory activation of KCs and could thus be a potential therapeutic target for the treatment of inflammation-related liver disease.

Gondoic acid alleviates LPS­induced Kupffer cells inflammation by inhibiting ROS production and PKCθ/ERK/STAT3 signaling pathway.

Kupffer cells (KCs) is the main macrophage in liver, and its inflammation is related to liver diseases. It has been shown that inflammatory macrophages are accompanied by changes in monounsaturated fatty acid (MUFA) content. However, the effect of gondoic acid (GA) on inflammation and its underlying mechanism have not been described. In the current study, we demonstrated that GA significantly inhibited the expression of pro-inflammatory factors in LPS-exposed KCs. Further research found that GA reduced lipopolysaccharide (LPS)-stimulated reactive oxygen species (ROS) levels and enhanced the expression of antioxidant genes. Meanwhile, GA obviously blocked the LPS-stimulated PKCθ/ERK/STAT3 signaling pathways to alleviate the inflammatory responses. These results demonstrated for the first time that GA improves KCs inflammation through the inhibition of ROS production and PKCθ/ERK/STAT3 signaling pathway, the results assist in the potential development of functional foods or prodrugs based on the GA rich plant oils.

ELISA and Chemiluminescent Enzyme Immunoassay for Sensitive and Specific Determination of Lead (II) in Water, Food and Feed Samples.

Lead is a heavy metal with increasing public health concerns on its accumulation in the food chain and environment. Immunoassays for the quantitative measurement of environmental heavy metals offer numerous advantages over other traditional methods. ELISA and chemiluminescent enzyme immunoassay (CLEIA), based on the mAb we generated, were developed for the detection of lead (II). In total, 50% inhibitory concentrations (IC50) of lead (II) were 9.4 ng/mL (ELISA) and 1.4 ng/mL (CLEIA); the limits of detection (LOD) were 0.7 ng/mL (ic-ELISA) and 0.1 ng/mL (ic-CLEIA), respectively. Cross-reactivities of the mAb toward other metal ions were less than 0.943%, indicating that the obtained mAb has high sensitivity and specificity. The recovery rates were 82.1%-108.3% (ic-ELISA) and 80.1%-98.8% (ic-CLEIA), respectively. The developed methods are feasible for the determination of trace lead (II) in various samples with high sensitivity, specificity, fastness, simplicity and accuracy.