1,25-Dihydroxyvitamin D3 Negatively Regulates the Inflammatory Response to Porcine Epidemic Diarrhea Virus Infection by Inhibiting NF-κB and JAK/STAT Signaling Pathway in IPEC-J2 Porcine Epithelial Cells.

Porcine epidemic diarrhea virus (PEDV) infection causes watery diarrhea and vomiting in piglets. The pathogenesis of PEDV infection is related to intestinal inflammation. It is known that 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) has potent anti-inflammatory activity, but it is unknown whether 1,25(OH)2D3 can inhibit the PEDV-induced inflammatory response and the underlying mechanism. We used transcriptome analysis, gene and protein expression, RNA interference and overexpression, and other techniques to study the anti-inflammatory effects of 1,25(OH)2D3 on PEDV infection in IPEC-J2 cells. The results showed that interleukin 19 (IL-19) and C-C motif chemokine ligand 20 (CCL20) gene expression were enhanced with the increase in PEDV infection time in IPEC-J2 cells. Interestingly, 1,25(OH)2D3 supplementation obviously inhibited IL-19 and CCL20 expression induced by PEDV. Meanwhile, we also found that 1,25(OH)2D3 reduced p-NF-κB, p-STAT1, and p-STAT3 protein levels induced by PEDV at 24 h post-infection. IκBα and SOCS3, NF-κB, and STAT inhibitor respectively, were increased by 1,25(OH)2D3 supplementation upon PEDV infection. In addition, 1,25(OH)2D3 supplementation inhibited ISG15 and MxA expression induced by PEDV. Although 1,25(OH)2D3 suppressed the JAK/STAT signal pathway and antiviral gene expression, it had no significant effects on PEDV replication and IFN-α-induced antiviral effects. In addition, when the vitamin D receptor (VDR) was silenced by siRNA, the anti-inflammatory effect of 1,25(OH)2D3 was inhibited. Meanwhile, the overexpression of VDR significantly downregulated IL-19 and CCL20 expression induced by PEDV infection. Together, our results provide powerful evidence that 1,25(OH)2D3 could alleviate PEDV-induced inflammation by regulating the NF-κB and JAK/STAT signaling pathways through VDR. These results suggest that vitamin D could contribute to inhibiting intestinal inflammation and alleviating intestinal damage in PEDV-infected piglets, which offers new approaches for the development of nutritional strategies to prevent PEDV infection in piglets.

1,25-Dihydroxyvitamin D3 inhibits porcine epidemic diarrhea virus replication by regulating cell cycle resumption in IPEC-J2 porcine epithelial cells.

Porcine epidemic diarrhea virus (PEDV) infection causes heavy economic losses in the pig industry. Currently, the lack of effective treatments prompts new antiviral researches. We have shown that 25-hydroxyvitamin D3 supplementation alleviated PEDV infection in weaned pigs before. However, it is not clear whether vitamin D inhibits PEDV replication. In this study, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) inhibited PEDV induced mitochondria damage and cell apoptosis. In addition, 1,25(OH)2D3 treatment decreased PEDV nucleocapsid gene and protein levels in IPEC-J2 cells. Transcriptomic data showed that PEDV infection altered the expression of 5316 genes (2498 up, 2818 down) in IPEC-J2 cells. The differentially expressed genes were mainly involved in cell cycle process, ribonucleoprotein complex biogenesis, mitotic nuclear division, and other biological processes. Then we examined the effects of PEDV infection on cell cycle progression in IPEC-J2 cells, and the results showed that PEDV induced G0/G1 phase arrest. G0/G1-phase arrest was also conducive to PEDV replication. However, 1,25(OH)2D3 treatment decreased G0/G1 phase percentage induced by PEDV. Cyclin D and cyclin E mRNA expression were also increased by 1,25(OH)2D3 supplementation upon PEDV infection. Moreover, the regulation of 1,25(OH)2D3 on cell cycle progression was abrogated by ERK1/2 inhibitor, as well as the mRNA expression of cyclin D. The inhibition of 1,25(OH)2D3 on PEDV replication was also eliminated by ERK1/2 inhibitor. Taken together, these results demonstrated that 1,25(OH)2D3 supplementation inhibited PEDV replication, and the anti-virus effect of 1,25(OH)2D3 was mediated in part by regulating cell cycle progression through ERK1/2 signaling pathway.

Dietary 25-Hydroxyvitamin D3 Supplementation Alleviates Porcine Epidemic Diarrhea Virus Infection by Improving Intestinal Structure and Immune Response in Weaned Pigs.

We conducted this experiment to determine if feeding 25-hydroxyvitamin D3 (25(OH)D3) to weaned pigs would alleviate porcine epidemic diarrhea virus (PEDV) infection and immune response. Forty-two weaned pigs were allotted to 1 of 6 dietary 25(OH)D3 treatments (5.5, 5.5, 43.0, 80.5, 118.0, 155.5 µg 25(OH)D3/kg diet) for 26 days. On day 22 of the trial, all the treatments were orally administrated with PEDV except for one of the 5.5 µg 25(OH)D3/kg treatments, which was challenged with the same volume of sterile saline and served as control. Another 5.5 µg 25(OH)D3/kg group for PEDV challenge was named CON-PEDV. Average daily gain (p < 0.05) was reduced by PEDV infection. PEDV administration also induced severe diarrhea (p < 0.05), reduction of villous height and the ratio of villous height to crypt depth, and increase of crypt depth and serum diamine oxidase activity (p < 0.05). Serum IgM and complement component 4 levels were increased by PEDV challenge. However, 155.5 µg 25(OH)D3/kg supplementation alleviated intestinal damage (p < 0.05) compared with CON-PEDV. Furthermore, 155.5 µg 25(OH)D3/kg supplementation downregulated the mRNA abundance of inflammatory cytokines and interferon signal pathway-related genes (p < 0.05) compared with CON-PEDV. These results suggested that dietary supplementation of 155.5 µg 25(OH)D3/kg could alleviate intestinal damage and protect against PEDV-induced inflammatory status.

Effects of dietary 25-hydroxyvitamin D3 supplementation on growth performance, immune function and antioxidative capacity in weaned piglets.

The study evaluated the effects of different doses of 25-hydroxyvitamin D3 (25(OH)D3) on growth performance, immune function and antioxidative capacity in piglets. In a 21-d trial, 35 weaned pigs were divided into five groups and diets were supplemented with 5.5 (control), 43.0, 80.5, 118.0 and 155.5 µg 25(OH)D3/kg, respectively. No treatment effects were observed for average daily gain, average daily feed intake and feed to gain ratio. Increasing dietary 25(OH)D3 levels increased serum 25(OH)D3 concentrations linearly (p < 0.01), decreased the frequency of CD3+CD4+ and CD3+CD8+ T cells (p < 0.01), and the serum level of complement component 3 (p < 0.05). Supplementation of 80.5 and 118.0 µg 25(OH)D3/kg enhanced the activity of serum glutathione peroxidase (p < 0.05) and addition of 43.0 µg 25(OH)D3/kg increased the malondialdehyde concentration (p < 0.05). Overall, feeding high-dose 25(OH)D3 to weaned pigs partly improved immune functions and the antioxidative capacity.

[Effects of Icariin on ovariectomized osteoporotic rats].

OBJECTIVE: To observe the effects of Icariin on ovariectomized osteoporotic rats. METHODS: Female Wistar rats were ovariectomized and administered different dosage of Icariin and 17beta-estradiol for eight weeks. Bone mineral density (BMD), indexes of biomechanics and bone metabolism-associated biochemical markers were measured. RESULTS: Icariin increased the BMD, maximum load and flexural rigidity in the osteoporotic rats. The activities of serum tartrate-resistant acid phosphatase (TRACP) and bone alkaline phosphatase (BALP) were decreased in the Icraiin-fed ovariectomized rats. CONCLUSION: Icariin 225mg/kg per day could increase the BMD and improve indexes of bone biomechanics in ovariectomized osteoporotic rats. It was effective in preventing bone loss induced by ovariectomy.