The inhibitory effect Polygonum Cillinerve polysaccharide on transmissible gastroenteritis virus of swine

Polygonum cuspidatum polysaccharide: A review of its extraction and purification, structure analysis, and biological activity

ETHNOPHARMACOLOGICAL RELEVANCE

Polygonum cuspidatum Sieb. et Zucc. is mainly distributed in Shanxi, Gansu, and Sichuan province of China. It is also found in Korea and Japan. Its dried roots and rhizomes are used as medicinal herbs and have been used to treat hyperglycemia and various inflammatory disorders.

AIM OF THE REVIEW

This paper aims to provide an up-to-date review of the developments in the studies involving the extraction and purification, structure analysis, pharmacological effects, and potential applications of polysaccharides obtained from Polygonum cuspidatum. Additionally, the possible future research directions of this plant are discussed.

MATERIALS AND METHODS

This article used "Polygonum cuspidatum polysaccharide (PCP)" and "Polygonum cuspidatum" as the keywords and gathered relevant data on Polygonum cuspidatum using electronic databases (Elsevier, PubMed, ACS, CNKI, Google Scholar, Baidu Scholar, Web of Science), relevant books, and classic literature about Chinese herb.

RESULTS

Excluding irrelevant and repetitive documents, 278 documents were finally included, of which 88 were in Chinese and 190 were in English. The CiteSpace software was used to visualize the trends and keywords in this research field. We concluded that the main extraction methods for Polygonum cuspidatum polysaccharide are water extraction and alcohol precipitation, microwave-assisted extraction, ultrasound-assisted extraction, and microjet extraction. High-performance liquid chromatography and column chromatography are also commonly used in the separation and purification of PCP. PCP has antitumor, immunomodulatory, hypoglycemic, and antioxidant effects. This paper provides an updated and deeper understanding of PCP, serving as a theoretical foundation for the further optimization of polysaccharide structures and the development of PCP as a novel functional material for clinical application.

Study on the immune-enhancing and inhabiting transmissible gastroenteritis virus effects of polysaccharides from Cimicifuga rhizoma

Cimicifugae rhizoma is a traditional Chinese herbal medicine in China, and modern pharmacological research showed that it has obvious antiviral activity. Many polysaccharides have been proved to have immune enhancement and antiviral activity, but there are few studies on the biological activity of Cimicifuga rhizoma polysaccharide (CRP). The aim was to explore the character of CRP and its effects on improving immune activity and inhibiting transmissible gastroenteritis virus (TGEV). The monosaccharide composition, molecular weight, fourier transform infrared spectra and electron microscopy analysis of CRP was measured. The effect of CRP on immune activity in lymphocytes and RAW264.7 cells were studied by colorimetry, FITC-OVA fluorescent staining and ELISA. The effect of CRP on TGEV-infected PK-15 cells was determined using Real-time PCR, Hoechst fluorescence staining, trypan blue staining, acridine orange staining, Annexin V-FITC/PI fluorescent staining, DCFH-DA loading probe, and JC-1 staining. Network pharmacology was used to predict the targets of CRP in enhancing immunity and anti-TGEV, and molecular docking was used to further analyze the binding mode between CPR and core targets. The results showed that CRP was mainly composed of glucose and galactose, and its molecular weight was 64.28 kDa. The content of iNOS and NO in CRP group were significantly higher than the control group. CRP (125 and 62.5 μg/mL) could significantly enhance the phagocytic capacity of RAW264.7 cells, and imprive the content of IL-1β content compared with control group. 250 μg/mL of CRP possessed the significant inhibitory effect on TGEV, which could significantly reduce the apoptosis compared to TGVE group and inhibit the decrease in mitochondrial membrane potential compared to TGVE group. The mRNA expression of TGEV N gene in CRP groups was significantly lower than TGEV group. PPI showed that the core targets of immune-enhancing were AKT1, MMP9, HSP90AA1, etc., and the core targets of TGE were CASP3, MMP9, EGFR, etc. Molecular docking show that CRP has binding potential with target. These results indicated that CRP possessed the better immune enhancement effect and anti-TGEV activity.

Phloretin inhibits transmissible gastroenteritis virus proliferation via multiple mechanisms

Transmissible gastroenteritis virus (TGEV), an enteropathogenic coronavirus, has caused huge economic losses to the pig industry, with 100% mortality in piglets aged 2 weeks and intestinal injury in pigs of other ages. However, there is still a shortage of safe and effective anti-TGEV drugs in clinics. In this study, phloretin, a naturally occurring dihydrochalcone glycoside, was identified as a potent antagonist of TGEV. Specifically, we found phloretin effectively inhibited TGEV proliferation in PK-15 cells, dose-dependently reducing the expression of TGEV N protein, mRNA, and virus titer. The anti-TGEV activity of phloretin was furthermore refined to target the internalization and replication stages. Moreover, we also found that phloretin could decrease the expression levels of proinflammatory cytokines induced by TGEV infection. In addition, we expanded the potential key targets associated with the anti-TGEV effect of phloretin to AR, CDK2, INS, ESR1, ESR2, EGFR, PGR, PPARG, PRKACA, and MAPK14 with the help of network pharmacology and molecular docking techniques. Furthermore, resistant viruses have been selected by culturing TGEV with increasing concentrations of phloretin. Resistance mutations were reproducibly mapped to the residue (S242) of main protease (Mpro). Molecular docking analysis showed that the mutation (S242F) significantly disrupted phloretin binding to Mpro, suggesting Mpro might be a potent target of phloretin. In summary, our findings indicate that phloretin is a promising drug candidate for combating TGEV, which may be helpful for developing pharmacotherapies for TGEV and other coronavirus infections.

Polygonum cillinerve polysaccharide inhibits transmissible gastroenteritis virus by regulating microRNA-181

Transmissible gastroenteritis virus (TGEV) is an important pathogen capable of altering the expression profile of cellular miRNA. In this study, the potential of Polygonum cillinerve polysaccharide (PCP) to treat TGEV-infected piglets was evaluated through in vivo experiments. High-throughput sequencing technology was employed to identify 9 up-regulated and 17 down-regulated miRNAs during PCP-mediated inhibition of TGEV infection in PK15 cells. Additionally, miR-181 was found to be associated with target genes of key proteins in the apoptosis pathway. PK15 cells were treated with various concentrations of PCP following transfection with miR-181 mimic or inhibitor. Real-time PCR assessed the impact on TGEV replication, while electron microscopy (TEM) and Hoechst fluorescence staining evaluated cellular functionality. Western blot analysis was utilized to assess the expression of key signaling factors-cytochrome C (cyt C), caspase 9, and P53-in the apoptotic signaling pathway. The results showed that compared with the control group, 250 μg/mL PCP significantly inhibited TGEV gRNA replication and gene N expression (P < 0.01). Microscopic examination revealed uniform cell morphology and fewer floating cells in PCP-treated groups (250 and 125 μg/mL). TEM analysis showed no typical virus structure in the 250 μg/mL PCP group, and apoptosis staining indicated a significant reduction in apoptotic cells at this concentration. Furthermore, PCP may inhibit TGEV-induced apoptosis via the Caspase-dependent mitochondrial pathway following miR-181 transfection. These findings provide a theoretical basis for further exploration into the mechanism of PCP's anti-TGEV properties.

Effect of miR-17 on Polygonum Cillinerve polysaccharide against transmissible gastroenteritis virus

Transmissible gastroenteritis virus (TGEV) could cause diarrhea, vomiting, dehydration and even death in piglets, miRNA played an important role in the interaction between virus and cell. The study aimed to investigate the impact of miR-17 on the polysaccharide of Polygonum Cillinerve (PCP) in combating TGEV. miR-17 was screened and transfection validation was performed by Real-time PCR. The function of miR-17 on PK15 cells infected with TGEV and treated with PCP was investigated by DCFH-DA loading probe, JC-1 staining and Hoechst fluorescence staining. Furthermore, the effect of miR-17 on PCP inhibiting TGEV replication and apoptosis signaling pathways during PCP against TGEV infection was measured through Real-time PCR and Western blot. The results showed that miR-17 mimic and inhibitor could be transferred into PK15 cells and the expression of miR-17 significantly increased and decreased respectively compared with miR-17 mimic and inhibitor (P < 0.05). A total 250 μg/mL of PCP could inhibit cells apoptosis after transfection with miR-17. PCP (250 μg/mL and 125 μg/mL) significantly inhibited the decrease in mitochondrial membrane potential induced by TGEV after transfection with miR-17 (P < 0.05). After transfection of miR-17 mimic, PCP at concentrations of 250 μg/mL and 125 μg/mL significantly promoted the mRNA expression of P53, cyt C and caspase 9 (P < 0.05). Compared with the control group, the replication of TGEV gRNA and gene N was significantly inhibited by PCP at concentrations of 250 μg/mL and 125 μg/mL after transfection of both miR-17 mimic and inhibitor (P < 0.05). PCP at 62.5 μg/mL significantly inhibited the replication of gene S following transfection with miR-17 inhibitor (P < 0.05). These results suggested that PCP could inhibit the replication of TGEV and apoptosis induced by TGEV by regulating miR-17.

All-trans retinoic acid alleviates transmissible gastroenteritis virus-induced intestinal inflammation and barrier dysfunction in weaned piglets

BACKGROUND

Transmissible gastroenteritis virus (TGEV) is one of the main pathogens causing severe diarrhea of piglets. The pathogenesis of TGEV is closely related to intestinal inflammation. All-trans retinoic acid (ATRA) is the main active metabolite of vitamin A, which has immunomodulatory and anti-inflammatory properties. However, it is unclear whether ATRA can alleviate TGEV-induced intestinal inflammation and barrier dysfunction in piglets. This study aimed to investigate the effects of ATRA on growth performance, diarrhea, intestinal inflammation and intestinal barrier integrity of TGEV-challenged piglets.

METHODS

In a 19-d study, 32 weaned piglets were randomly divided into 4 treatments: Control group (basal diet), TGEV group (basal diet + TGEV challenge), TGEV + ATRA5 group (basal diet + 5 mg/d ATRA + TGEV challenge) and TGEV + ATRA15 group (basal diet + 15 mg/d ATRA + TGEV challenge). On d 14, piglets were orally administered TGEV or the sterile medium.

RESULTS

Feeding piglets with 5 and 15 mg/d ATRA alleviated the growth inhibition and diarrhea induced by TGEV (P < 0.05). Feeding piglets with 5 and 15 mg/d ATRA also inhibited the increase of serum diamine oxidase (DAO) activity and the decrease of occludin and claudin-1 protein levels in jejunal mucosa induced by TGEV, and maintained intestinal barrier integrity (P < 0.05). Meanwhile, 5 mg/d ATRA feeding increased the sucrase activity and the expressions of nutrient transporter related genes (GLUT2 and SLC7A1) in jejunal mucosa of TGEV-challenged piglets (P < 0.05). Furthermore, 5 mg/d ATRA feeding attenuated TGEV-induced intestinal inflammatory response by inhibiting the release of interleukin (IL)-1β, IL-8 and tumor necrosis factor-α (TNF-α), and promoting the secretion of IL-10 and secretory immunoglobulin A (sIgA) (P < 0.05). Feeding 5 mg/d ATRA also down-regulated the expressions of Toll-like receptors and RIG-I like receptors signaling pathway related genes (TLR3, TLR4, RIG-I, MyD88, TRIF and MAVS) and the phosphorylation level of nuclear factor-κB-p65 (NF-κB p65), and up-regulated the inhibitor kappa B alpha (IκBα) protein level in jejunal mucosa of TGEV-challenged piglets (P < 0.05).

CONCLUSIONS

ATRA alleviated TGEV-induced intestinal barrier damage by inhibiting inflammatory response, thus improving the growth performance and inhibiting diarrhea of piglets. The mechanism was associated with the inhibition of NF-κB signaling pathway mediated by TLR3, TLR4 and RIG-I.

Plantago asiatica L. polysaccharides: Physiochemical properties, structural characteristics, biological activity and application prospects: A review

Plantago asiatica L. (PAL), a traditional herb, has been used in East Asia for thousands of years. In recent years, polysaccharides extracted from PAL have garnered increased attention due to their outstanding pharmacological and biological properties. Previous research has established that PAL-derived polysaccharides exhibit antioxidant, anti-inflammatory, antidiabetic, antitumor, antimicrobial, immune-regulatory, intestinal health-promoting, antiviral, and other effects. Nevertheless, a comprehensive summary of the research related to Plantago asiatica L. polysaccharides (PALP) has not been reported to date. In this paper, we review the methods for isolation and purification, physiochemical properties, structural features, and biological activities of PALP. To provide a foundation for research and application in the fields of medicine and food, this review also outlines the future development prospects of plantain polysaccharides.

A Review of Bioactive Compounds against Porcine Enteric Coronaviruses

Pig diarrhea is a universal problem in the process of pig breeding, which seriously affects the development of the pig industry. Porcine enteric coronaviruses (PECoVs) are common pathogens causing diarrhea in pigs, currently including transmissible gastroenteritis virus (TGEV), porcine epidemic diarrhea virus (PEDV), porcine deltacoronavirus (PDCoV) and swine acute diarrhea syndrome coronavirus (SADS-CoV). With the prosperity of world transportation and trade, the spread of viruses is becoming wider and faster, making it even more necessary to prevent PECoVs. In this paper, the host factors required for the efficient replication of these CoVs and the compounds that exhibit inhibitory effects on them were summarized to promote the development of drugs against PECoVs. This study will be also helpful in discovering general host factors that affect the replication of CoVs and provide references for the prevention and treatment of other CoVs.

Eugenol Attenuates Transmissible Gastroenteritis Virus-Induced Oxidative Stress and Apoptosis Via ROS-NRF2-ARE Signaling

Transmissible gastroenteritis virus (TGEV), a coronavirus that causes severe diarrhea due to oxidative stress in the piglet intestine, is a major cause of economic loss in the livestock industry. However, limited interventions have been shown to be effective in the treatment of TGEV. Here, we demonstrate the therapeutic activity of eugenol in TGEV-induced intestinal oxidative stress and apoptosis. Our data show that eugenol supplementation protects intestine and IPEC-J2 cells from TGEV-induced damage. Mechanistically, eugenol reduces TGEV-induced oxidative stress in intestinal epithelial cells by reducing reactive oxygen species levels. Interestingly, eugenol also inhibits TGEV-induced intestinal cell apoptosis in vitro and in vivo. In conclusion, our data suggest that eugenol prevents TGEV-induced intestinal oxidative stress by reducing ROS-mediated damage to antioxidant signaling pathways. Therefore, eugenol may be a promising therapeutic strategy for TGEV infection.

Antiviral Activity of Plantago asiatica Polysaccharide against Pseudorabies Virus In Vitro

Pseudorabies (PR) is an acute infectious disease of various domestic animals and wild animals caused by pseudorabies virus (PRV). It is mainly characterized by fever, itching, encephalomyelitis, and respiratory and neurological disorders. Plantago asiatica polysaccharide (PLP), extracted from the whole plant of Plantago asiatica L., showed immunomodulatory and antioxidation effects, but the antiviral activity had not been reported. In this study, the inhibitory effect of PLP on PRV infection was studied. Our study first revealed that PLP could inhibit PRV infection in a dose-dependent manner. By adding PLP at different stages of the virus's life cycle, we revealed that PLP could reduce the attachment and penetration of PRV into PK15 cells. The inhibition of PRV attachment was better than inhibition of PRV penetration. However, PLP did not affect PRV replication and inactivation. In addition, PLP decreased the intracellular ROS levels in infected cells significantly, and ROS scavenger NAC decreased PRV infection. Therefore, our study provided preliminary data of anti-PRV activity of PLP, which was established to be a novel anti-PRV infection agent.