Paeoniflorin Upregulates β-Defensin-2 Expression in Human Bronchial Epithelial Cell Through the p38 MAPK, ERK, and NF-κB Signaling Pathways

The Role of Innate Immunity in Healthy Aging Through Antimicrobial Peptides

In a super-aging society, the increase in the elderly population is closely tied to a rise in infectious diseases due to factors such as weakened immune systems and decreased vaccine efficacy in older adults. Various opportunistic pathogens commonly encountered in everyday life can cause infections and diseases when an individual's immune defence is weakened due to aging. These factors underscore the importance of preventive measures against pathogenic infections and the aging of immune systems in the elderly. The immune response acts as the defence mechanism against foreign substances, including pathogens and abnormal cells. Specifically, the innate immune response is the body's first line of defence, offering a rapid and nonspecific response to pathogens. Advances in the study of innate immunity's regulatory functions in both immune and non-immune cells have broadened our understanding of innate immune responses' impact on health. This includes a focus on immune effectors like antimicrobial peptides (AMPs) and their potential implications for health and longevity. This review summarises the common principles and evolutionary adaptations of innate immunity via AMPs, in mammals and invertebrates. Especially, this review discusses the conserved mechanisms regulating AMP production and the role of AMPs in modulating aging and diseases from invertebrate to human. Therefore, it highlights the potential role of innate immunity in addressing aging through AMPs.

Oleanolic acid improved intestinal immune function by activating and potentiating bile acids receptor signaling in E. coli-challenged piglets

BACKGROUND

Infection with pathogenic bacteria during nonantibiotic breeding is one of the main causes of animal intestinal diseases. Oleanolic acid (OA) is a pentacyclic triterpene that is ubiquitous in plants. Our previous work demonstrated the protective effect of OA on intestinal health, but the underlying molecular mechanisms remain unclear. This study investigated whether dietary supplementation with OA can prevent diarrhea and intestinal immune dysregulation caused by enterotoxigenic Escherichia coli (ETEC) in piglets. The key molecular role of bile acid receptor signaling in this process has also been explored.

RESULTS

Our results demonstrated that OA supplementation alleviated the disturbance of bile acid metabolism in ETEC-infected piglets (P < 0.05). OA supplementation stabilized the composition of the bile acid pool in piglets by regulating the enterohepatic circulation of bile acids and significantly increased the contents of UDCA and CDCA in the ileum and cecum (P < 0.05). This may also explain why OA can maintain the stability of the intestinal microbiota structure in ETEC-challenged piglets. In addition, as a natural ligand of bile acid receptors, OA can reduce the severity of intestinal inflammation and enhance the strength of intestinal epithelial cell antimicrobial programs through the bile acid receptors TGR5 and FXR (P < 0.05). Specifically, OA inhibited NF-κB-mediated intestinal inflammation by directly activating TGR5 and its downstream cAMP-PKA-CREB signaling pathway (P < 0.05). Furthermore, OA enhanced CDCA-mediated MEK-ERK signaling in intestinal epithelial cells by upregulating the expression of FXR (P < 0.05), thereby upregulating the expression of endogenous defense molecules in intestinal epithelial cells.

CONCLUSIONS

In conclusion, our findings suggest that OA-mediated regulation of bile acid metabolism plays an important role in the innate immune response, which provides a new diet-based intervention for intestinal diseases caused by pathogenic bacterial infections in piglets.

Mechanisms and regulation of defensins in host defense

As a family of cationic host defense peptides, defensins are mainly synthesized by Paneth cells, neutrophils, and epithelial cells, contributing to host defense. Their biological functions in innate immunity, as well as their structure and activity relationships, along with their mechanisms of action and therapeutic potential, have been of great interest in recent years. To highlight the key research into the role of defensins in human and animal health, we first describe their research history, structural features, evolution, and antimicrobial mechanisms. Next, we cover the role of defensins in immune homeostasis, chemotaxis, mucosal barrier function, gut microbiota regulation, intestinal development and regulation of cell death. Further, we discuss their clinical relevance and therapeutic potential in various diseases, including infectious disease, inflammatory bowel disease, diabetes and obesity, chronic inflammatory lung disease, periodontitis and cancer. Finally, we summarize the current knowledge regarding the nutrient-dependent regulation of defensins, including fatty acids, amino acids, microelements, plant extracts, and probiotics, while considering the clinical application of such regulation. Together, the review summarizes the various biological functions, mechanism of actions and potential clinical significance of defensins, along with the challenges in developing defensins-based therapy, thus providing crucial insights into their biology and potential clinical utility.

Induction of Endogenous Antimicrobial Peptides to Prevent or Treat Oral Infection and Inflammation

Antibiotics are often used to treat oral infections. Unfortunately, excessive antibiotic use can adversely alter oral microbiomes and promote the development of antibiotic-resistant microorganisms, which can be difficult to treat. An alternate approach could be to induce the local transcription and expression of endogenous oral antimicrobial peptides (AMPs). To assess the feasibility and benefits of this approach, we conducted literature searches to identify (i) the AMPs expressed in the oral cavity; (ii) the methods used to induce endogenous AMP expression; and (iii) the roles that expressed AMPs may have in regulating oral inflammation, immunity, healing, and pain. Search results identified human neutrophil peptides (HNP), human beta defensins (HBD), and cathelicidin AMP (CAMP) gene product LL-37 as prominent AMPs expressed by oral cells and tissues. HNP, HBD, and LL-37 expression can be induced by micronutrients (trace elements, elements, and vitamins), nutrients, macronutrients (mono-, di-, and polysaccharides, amino acids, pyropeptides, proteins, and fatty acids), proinflammatory agonists, thyroid hormones, and exposure to ultraviolet (UV) irradiation, red light, or near infrared radiation (NIR). Localized AMP expression can help reduce infection, inflammation, and pain and help oral tissues heal. The use of a specific inducer depends upon the overall objective. Inducing the expression of AMPs through beneficial foods would be suitable for long-term health protection. Additionally, the specialized metabolites or concentrated extracts that are utilized as dosage forms would maintain the oral and intestinal microbiome composition and control oral and intestinal infections. Inducing AMP expression using irradiation methodologies would be applicable to a specific oral treatment area in addition to controlling local infections while regulating inflammatory and healing processes.

Preventing Respiratory Viral Diseases with Antimicrobial Peptide Master Regulators in the Lung Airway Habitat

The vast surface area of the respiratory system acts as an initial site of contact for microbes and foreign particles. The whole respiratory epithelium is covered with a thin layer of the airway and alveolar secretions. Respiratory secretions contain host defense peptides (HDPs), such as defensins and cathelicidins, which are the best-studied antimicrobial components expressed in the respiratory tract. HDPs have an important role in the human body's initial line of defense against pathogenic microbes. Epithelial and immunological cells produce HDPs in the surface fluids of the lungs, which act as endogenous antibiotics in the respiratory tract. The production and action of these antimicrobial peptides (AMPs) are critical in the host's defense against respiratory infections. In this study, we have described all the HDPs secreted in the respiratory tract as well as how their expression is regulated during respiratory disorders. We focused on the transcriptional expression and regulation mechanisms of respiratory tract HDPs. Understanding how HDPs are controlled throughout infections might provide an alternative to relying on the host's innate immunity to combat respiratory viral infections.

Current knowledge of leptin in wound healing: A collaborative review

Efficacious wound healing is still a major concern for global healthcare due to the unsatisfactory outcomes under the current treatments. Leptin, an adipocyte-derived hormone, mainly acts in the hypothalamus and plays crucial roles in various biological processes. Recently, an increasing number of researches have shown that leptin played an important role in the wound healing process. In this review, we presented a first attempt to capture the current knowledge on the association between leptin and wound healing. After a comprehensive review, the molecular mechanisms underlying leptin in wound healing were speculated to be correlated to the regulation of inflammation of the macrophage and lymphocytes, angiogenesis, re-epithelialization, proliferation, and differentiation of fibroblasts. The affected genes and the signal pathways were multiple. For example, leptin was reported to ameliorate wound healing by its anti-inflammatory action, which might be correlated to the activation STAT1 and STAT3 via p38 MAPK or JAK2. However, the understanding of the specific role in each process (e.g., inflammatory, proliferative, and maturation phase) of wound repair is not entirely clear, and further studies are still warranted in both macrostructural and microscale factors. Therefore, identifying and validating the biological mechanisms of leptin in wound healing is of great significance to develop potential therapeutic targets for the treatment of wound healing in clinical practice.

Effect of paeoniflorin on acute lung injury induced by influenza A virus in mice. Evidences of its mechanism of action

BACKGROUND

Influenza often leads to acute lung injury (ALI). Few therapeutics options such as vaccines and other antiviral drugs are available. Paeoniflorin is a monoterpene glucoside isolated from the roots of Paeonia lactiflora Pall. that has showed good anti-inflammatory and anti-fibrotic effects. However, it is not known whether paeoniflorin has an effect on influenza virus-induced ALI.

PURPOSE

To investigative the protective effect and potential mechanism of paeoniflorin on ALI induced by influenza A virus (IAV).

STUDY DESIGN AND METHODS

The anti-influenza activity of paeoniflorin in vitro was investigated. Influenza virus A/FM/1/47 was intranasally infected in mice to induce ALI, and paeoniflorin (50 and 100 mg/kg) was given orally to mice during 5 days, beginning 2 h after infection. On day 6 post-infection, body and lung weights, histology and survival were observed, and the lungs were examined for viral load, cytokine and cellular pathway protein expression.

RESULTS

Results showed that paeoniflorin (50 and 100 mg/kg) reduced IAV-induced ALI. It reduces pulmonary oedema and improves histopathological changes in the lung, and also diminishes the accumulation of inflammatory cells in the lung. It was shown that paeoniflorin (50 and 100 mg/kg) alleviated IAV-induced ALI, as evidenced by improved survival in infected mice (40% and 50%, respectively), reduced viral titer in lung tissue, improved histological changes, and reduced lung inflammation. Paeoniflorin also improves pulmonary fibrosis by reducing the levels of pulmonary fibrotic markers (collagen type IV, alpha-smooth muscle actin, hyaluronic acid, laminin, and procollagen type III) and downregulating the expression levels of type I collagen (Col I) and type III collagen (Col III) in the lung tissues. Additionally, paeoniflorin inhibits the expression of αvβ3, TGF-β1, Smad2, NF-κB, and p38MAPK in the lung tissues.

CONCLUSION

The results showed that paeoniflorin (50 and 100 mg/kg) protected against IAV-induced ALI, and the underlying mechanism may be related to the reduction of pro-inflammatory cytokine production and lung collagen deposition through down-regulation of activation of αvβ3/TGF-β1 pathway in lung tissue.

Phytopharmaceuticals mediated Furin and TMPRSS2 receptor blocking: can it be a potential therapeutic option for Covid-19?

BACKGROUND

Currently, novel coronavirus disease (Covid-19) outbreak creates global panic across the continents, as people from almost all countries and territories have been affected by this highly contagious viral disease. The scenario is deteriorating due to lack of proper & specific target-oriented pharmacologically safe prophylactic agents or drugs, and or any effective vaccine. drug development is urgently required to back in the normalcy in the community and to combat this pandemic.

PURPOSE

Thus, we have proposed two novel drug targets, Furin and TMPRSS2, as Covid-19 treatment strategy. We have highlighted this target-oriented novel drug delivery strategy, based on their pathophysiological implication on SARS-CoV-2 infection, as evident from earlier SARS-CoV-1, MERS, and influenza virus infection via host cell entry, priming, fusion, and endocytosis. STUDY DESIGN &  METHODS: An earlier study suggested that Furin and TMPRSS2 knockout mice had reduced level of viral load and a lower degree of organ damage such as the lung. The present study thus highlights the promise of some selected novel and potential anti-viral Phytopharmaceutical that bind to Furin and TMPRSS2 as target.

RESULT

Few of them had shown promising anti-viral response in both preclinical and clinical study with acceptable therapeutic safety-index.

CONCLUSION

Hence, this strategy may limit life-threatening Covid-19 infection and its mortality rate through nano-suspension based intra-nasal or oral nebulizer spray, to treat mild to moderate SARS-COV-2 infection when Furin and TMPRSS2 receptor may initiate to express and activate for processing the virus to cause cellular infection by replication within the host cell and blocking of host-viral interaction.

EGCG induces β-defensin 3 against influenza A virus H1N1 by the MAPK signaling pathway

Epigallocatechin gallate (EGCG) is the main component of green tea, which has been proven to inhibit a variety of viruses, including influenza A virus. However, the mechanism of EGCG against influenza virus remains to be further explored. The mechanism of EGCG against influenza virus was studied. The results showed that EGCG significantly increased the levels of HBD3 mRNA and protein, while the levels of phosphorylation of (p)-p38 MAPK, ERK and JNK after EGCG treatment were significantly up-regulated. p38 MAPK, ERK and JNK inhibitors significantly inhibited the expression of HBD3 induced by EGCG. On the other hand, EGCG significantly inhibited the expression of HA and NP proteins in influenza A virus H1N1, but attenuated the anti-influenza A virus effect of EGCG after silencing HBD3. Thus, the anti-influenza virus effect of EGCG is related to the induction of HBD3 expression. In addition, the expression of EGCG-induced HBD3 is related to the p38 MAPK, ERK and JNK signaling pathways. The research data show that EGCG can induce HBD3 expression through p38 MAPK, ERK and JNK signaling pathway to inhibit the replication of influenza A virus H1N1, providing a new and effective candidate drug for influenza virus.

Inducible expression of defensins and cathelicidins by nutrients and associated regulatory mechanisms

Host defense peptides (HDPs) are crucial components of the body's first line of defense that protect organisms from infections and mediate immune responses. Defensins and cathelicidins are the two most important families of HDPs in mammals. In this review, we summarize the nutrients that are involved in inducible expression of endogenous defensins and cathelicidins. In addition, the mitogen-activated protein kinases (MAPK), nuclear factor kappa B (NF-κB) and histone deacetylase (HDAC) signaling pathways that play vital roles in the induction of defensin and cathelicidin expression are highlighted. Endogenous defensins and cathelicidins induced by nutrients may be potential alternatives to antibiotic treatments against infection and diseases. This review mainly focuses on the inducible expression and regulatory mechanisms of defensins and cathelicidins in multiple species by different nutrients and the potential applications of defensin- and cathelicidin-inducing nutrients.

Saccharomyces cerevisiae β-glucan-induced SBD-1 expression in ovine ruminal epithelial cells is mediated through the TLR-2-MyD88-NF-κB/MAPK pathway

Ovine ruminal epithelial cells (ORECs) not only have a physical barrier function but also can secrete host defence peptides (HDPs), such as sheep β-defensin-1 (SBD-1). As a feed additive, Saccharomyces cerevisiae can enhance the host's innate immunity. β-glucan, a cell wall component of Saccharomyces cerevisiae, can stimulate innate immune responses and trigger the up-regulation of SBD-1 in ORECs. The signaling mechanisms involved in β-glucan-induced SBD-1 expression are not completely understood. The aim of this study was to identify the receptors and intracellular pathways involved in the up-regulation of SBD-1 induced by β-glucan. ORECs were cultured, and the regulatory mechanisms of β-glucan-induced up-regulation of SBD-1 were detected using quantitative real-time PCR (qPCR), enzyme-linked immunosorbent assay (ELISA), and western blotting. TLR-2 and MyD88 knockdown or inhibition attenuated β-glucan-induced SBD-1 expression. We also showed that inhibition of MAPK and NF-κB pathways significantly reduced β-glucan-induced SBD-1 expression. These results demonstrate that β-glucan-induced SBD-1 expression is TLR-2-MyD88-dependent and may be regulated by both MAPK and NF-κB pathways. Since NF-κB inhibition had a greater effect on the down-regulation of β-glucan-induced SBD-1 expression, the NF-κB pathway may be the dominant signaling pathway involved in the regulation of defensin expression. Our studies demonstrate that β-glucan-induced SBD-1 expression is mediated through the TLR-2-MyD88-NF-κB/MAPK pathway. Our results would contribute to the understanding of immunological modulations in the gastrointestinal tract triggered by probiotic yeast cell wall components.

Differential Expression of Antimicrobial Peptides in Streptococcus pneumoniae Keratitis and STAT3-Dependent Expression of LL-37 by Streptococcus pneumoniae in Human Corneal Epithelial Cells

Streptococcus pneumoniae is the leading cause of bacterial keratitis in the developing world with a growing trend of acquiring resistance against various antibiotics. In the current study, we determined the expression of different antimicrobial peptides (AMPs) in response to S. pneumoniae in patients, as well as in primary and immortalized human corneal epithelial cells. We further focused on LL-37 and determined its expression in human cornea infected with S. pneumoniae and studied the killing ability of LL-37 against S. pneumoniae. The expression of AMPs was determined by quantitative PCR and the phosphorylation of signaling proteins was evaluated by immunoblot analysis. LL-37 expression was also determined by immunofluorescence and Western blot method and the killing ability of LL-37 against S. pneumoniae was determined by colony-forming units. Differential expression of antimicrobial peptides was observed in patients with S. pneumoniae keratitis. Although S. pneumoniae induced expression of the AMPs in human corneal epithelial cells (HCEC), it did not induce AMP expression in U937, a human monocyte cell line. S. pneumoniae also caused activation of nuclear factor kappa-light-chain enhancer of activated B cells (NF-κB)and mitogen activated protein kinase (MAPK) pathways in corneal epithelial cells. LL-37 was found to be effective against both laboratory and clinical strains of S. pneumoniae. LL-37 induction by S. pneumoniae in human corneal epithelial cells was mediated by signal transducer and activator of transcription 3 (STAT3) activation, and inhibition of STAT3 activation significantly reduced LL-37 expression. Our study determines an extensive profile of AMPs expressed in the human cornea during S. pneumoniae infection, and suggests the potential of LL-37 to be developed as an alternative therapeutic intervention to fight increasing antibiotic resistance among bacteria.

Saccharomyces cerevisiae mannan induces sheep beta-defensin-1 expression via Dectin-2-Syk-p38 pathways in ovine ruminal epithelial cells

The rumen epithelium of sheep serves as an immune interface with the environment and secretes antimicrobial peptides with bactericidal function against various pathogens. Sheep beta-defensin-1 (SBD-1), an antimicrobial peptide, is secreted from ovine ruminal epithelial cells (OREC) in response to microbial infections. Mannan, the main component of the Saccharomyces cerevisiae cell wall can stimulate innate and regulatory immune responses that could improve the gastrointestinal environment. We aimed at investigating the effects of mannan on SBD-1 expression and the downstream signaling pathways stimulated in OREC. We cultured OREC; assessed the effects of mannan on SBD-1 expression by qPCR and ELISA; and then investigated the underlying signaling pathways using qPCR, ELISA, Western blotting, immunohistochemistry, and immunohistofluorescence. Interestingly, mannan markedly upregulated SBD-1 expression in a concentration- and time-dependent manner. Dectin-2 Mouse mAb, Syk specific inhibitor R406, and specific inhibitors of the p38, ERK1/2, JNK, and NF-κB pathways attenuated mannan-induced SBD-1 expression to varying degrees. These results demonstrate that SBD-1 is upregulated by mannan via the Dectin-2-Syk axis, and this is regulated to a large extent through the mitogen-activated protein kinase (MAPK) p38 and less so through the ERK1/2 and JNK or the NF-κB pathway. Our findings highlight the immunomodulatory effects of mannan on OREC in terms of mannan-induced SBD-1 expression.

Astragalus polysaccharides exerts anti-infective activity by inducing human cathelicidin antimicrobial peptide LL-37 in respiratory epithelial cells

Astragalus polysaccharides (APS), one of the major active components in Astragalus membranaceus, is an effective immunomodulator used in the treatment of immunological diseases in China. However, the anti-infective action and mechanism of APS is not fully known. In the present study, we found that APS induced the expression of human cathelicidin antimicrobial peptide LL-37, a key host anti-infective molecule, in both mRNA and protein levels in respiratory epithelial cells HBE16 and A549. Furthermore, the lysate and supernatant from APS-treated HBE16 cells both exhibited an obvious antibacterial action, which was partially neutralizated by LL-37 monoclonal antibody. In addition, APS also significantly elevated the phosphorylation of p38 MAPK and JNK and caused the degradation of IκBα. Specific inhibitors of p38 MAPK, JNK, or NF-κB obviously abolished APS-induced LL-37 synthesis and antibacterial activity, respectively. Taken together, our results confirmed the enhancement of APS on LL-37 induction and antibacterial action in respiratory epithelial cells, which may be attributed to activation of p38 MAPK/JNK and NF-κB pathways. Furthermore, these results also supported the clinical application of APS in the treatment of infectious diseases.

Paeoniflorin inhibits proliferation of endometrial cancer cells via activating MAPK and NF-κB signaling pathways

Paeoniflorin (PAE), a principal bioactive component of Paeonia lactiflora Pall., appears to have antitumor properties. However, the pharmacological activity of PAE in endometrial cancer and the specific mechanisms have remained largely elusive. The present study aimed to determine the antitumor activity of PAE in the human endometrial cancer cell line RL95-2 and explore the potential mechanisms. Cell proliferation was assessed to evaluate the antitumor effect of PAE towards RL95-2 cells via a Cell Counting Kit-8 assay. Protein expression was examined to investigate changes in the signaling pathways of p38 mitogen-activated protein kinase (MAPK), c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK) and nuclear factor (NF)-κB in RL95-2 cells during PAE treatment by western blot analysis. The results revealed that PAE significantly and dose- and time-dependently inhibited the proliferation of RL95-2 cells. In addition, PAE activated MAPK signaling pathways (p38, JNK and ERK) and the NF-κB signaling pathway. Furthermore, p38 MAPK and NF-κB inhibitors (SB203580 and MG-132, respectively) prevented PAE-induced proliferative inhibition in RL95-2 cells. However, ERK and JNK inhibitors (PD98059 and BI-78D3, respectively) did not produce such an inhibition. In conclusion, the present study demonstrated that PAE exerts its anti-proliferative activity via activating p38 MAPK and NF-κB signaling pathways in endometrial cancer cells, providing a potential new drug of choice for endometrial cancer therapy.

Reduction of Ischemic Brain Edema by Combined use of Paeoniflorin and Astragaloside IV via Down-Regulating Connexin 43

Paeoniflorin (PF) and astragaloside IV (AS-IV) have protective effects on cerebral ischemia. We aimed to test the effects of combined use of PF and AS-IV on ischemic brain edema and investigate whether the effects were dependent on connexin43 (Cx43). We detected the expression of Cx43 induced by PF and AS-IV after cerebral ischemia. We also examined the effects of combined use of PF and AS-IV on ischemic edema and further investigated the related pathways. We demonstrated PF and AS-IV decreased Cx43 and aquaporin4 (AQP4) associating with reduction of brain edema by dry-wet weight and brain-specific gravity methods after cerebral ischemia. Administration of PF and AS-IV displayed a further attenuation of brain edema with lower Cx43 levels. Meanwhile, Cx43 blockade inhibited AQP4 down-regulation by the two drugs. Moreover, phosphorylation of C-Jun amino-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) were increased by PF and AS-IV, respectively. The effects of PF and AS-IV to down-regulate Cx43 were suppressed by JNK and ERK inhibitors, respectively. Our data indicate that PF and AS-IV alleviate ischemic brain edema, which has close relation to Cx43 down-regulation causing decrease of AQP4 via JNK and ERK pathways activation, respectively. Combined administration elicits synergistic effects on brain edema reduction. Copyright © 2017 John Wiley & Sons, Ltd.

Identification of NF-κB as Determinant of Posttraumatic Stress Disorder and Its Inhibition by the Chinese Herbal Remedy Free and Easy Wanderer

Posttraumatic stress disorder (PTSD) is a mental disorder developing after exposure to traumatic events. Although psychotherapy reveals some therapeutic effectiveness, clinically sustainable cure is still uncertain. Some Chinese herbal formulae are reported to work well clinically against mental diseases in Asian countries, but the safety and their mode of action are still unclear. In this study, we investigated the mechanisms of Chinese remedy free and easy wanderer (FAEW) on PTSD. We used a reverse pharmacology approach combining clinical data to search for mechanisms of PTSD with subsequent in vitro verification and bioinformatics techniques as follows: (1) by analyzing microarray-based transcriptome-wide mRNA expression profiling of PTSD patients; (2) by investigating the effect of FAEW and the antidepressant control drug fluoxetine on the transcription factor NF-κB using reporter cell assays and western blotting; (3) by performing molecular docking and literature data mining based on phytochemical constituents of FAEW. The results suggest an involvement of inflammatory processes mediated through NF-κB in the progression of PTSD. FAEW was non-cytotoxic in vitro and inhibited NF-κB activity and p65 protein expression. FAEW's anti-inflammatory compounds, i.e., paeoniflorin, isoliquiritin, isoliquiritin apioside and ononin were evaluated for binding to IκK and p65-RelA in a molecular docking approach. Paeoniflorin, albiflorin, baicalin, isoliquiritin and liquiritin have been reported to relieve depression in vivo or in clinical trials, which might be the active ingredients for FAEW against PTSD.

Paeoniflorin ameliorates ANIT-induced cholestasis by activating Nrf2 through an PI3K/Akt-dependent pathway in rats

Cholestasis causes hepatic accumulation of bile acids leading to liver injury, fibrosis and liver failure. Paeoniflorin, the major active compound isolated from the roots of Paeonia lactiflora pall and Paeonia veitchii Lynch, is extensively used for liver diseases treatment in China. However, the mechanism of paeoniflorin's hepatoprotective effect on cholestasis has not been investigated yet. In this study, we administered paeoniflorin to rats for 3 days prior to alpha-naphthylisothiocyanate (ANIT) administration for once, then went on administering paeoniflorin to rats for 3 days. The data demonstrated that paeoniflorin significantly prevented ANIT-induced change in serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphates (ALP), serum total bilirubin (TBIL), direct bilirubin (DBIL), total bile acid (TBA) and gamma-glutamyl transpeptidase (γ-GT). Histology examination revealed that paeoniflorin treatment rats relieved more liver injury and bile duct proliferation than ANIT-administered rats. Moreover, our data indicated that paeoniflorin could restore glutathione (GSH) and its related synthase glutamate-cysteine ligase catalytic subunit (GCLc) and glutamate-cysteine ligase modifier subunit (GCLm) in ANIT-treated group. In addition, the RNA and protein expression of Akt and nuclear factor-E2-related factor-2 (Nrf2) were also activated by paeoniflorin in ANIT-induced rats. These findings indicated that paeoniflorin protected ANIT-induced cholestasis and increased GSH synthesis by activating Nrf2 through PI3K/Akt-dependent pathway. Therefore, paeoniflorin might be a potential therapeutic agent for cholestasis.

Dehydroandrographolide enhances innate immunity of intestinal tract through up-regulation the expression of hBD-2

Background

Dehydroandrographolide (DA) is one of major active components in the well-known oriental herbal medicine Andrographis paniculata (Burm.f) Nees which belongs to the Acanthaceae family. DA is used for the treatment of infections in China. However, DA has not been found to significantly inhibit bacterial and viral growth directly. The current study investigates the effect of DA on the expression of human β –defensin-2 (hBD-2) in human intestinal epithelial cells and the possible signaling pathways.

Methods

Human intestinal epithelial HCT-116 cells were incubated with 1–100 μM DA for 2–24 h. RT–PCR and Western blot were used to assess the expression of hBD-2. The specific inhibitors were used and the levels of phosphorylation of signaling molecules were detected for dissecting the signaling pathways leading to the induction of hBD-2.

Results

MTT assay showed there was no obvious cytotoxicity for HCT-116 cells by 1–100 μM DA treatment. RT-PCR and Western blot assays showed that DA (1–100 μM) could up-regulate the expression of hBD-2, and the effect lasted longer than 24 h. By using SB203580 and SB202190 (inhibitors of p38), the enhancement of hBD-2 expression were significantly attenuated. However, inhibitor of ERK and inhibitor of JNK could not block the effect of DA. Furthermore, Western blot found activation of p38 but not ERK and JNK in DA-treated HCT-116 cells.

Conclusion

The results suggested that DA enhanced innate immunity of intestinal tract by up-regulating the expression of hBD-2 through the p38 MAPK pathways.

Porcine β-defensin 2 attenuates inflammation and mucosal lesions in dextran sodium sulfate-induced colitis

Intestinal permeability plays a critical role in the etiopathogenesis of ulcerative colitis. Defensins, including porcine β-defensin (pBD)2, are crucial antimicrobial peptides for gut protection owing to their antibacterial and immunomodulatory activities. The purpose of this study was to investigate the protective effects of pBD2 on mucosal injury and the disruption of the epithelial barrier during the pathological process of dextran sodium sulfate (DSS)-induced colitis. The effects and mechanism of pBD2 were evaluated both using a DSS-induced C57BL/6 mouse model and, in vitro, using Caco-2 and RAW264.7 cells. DSS-induced colitis was characterized by higher disease activity index, shortened colon length, elevated activities of myeloperoxidase and eosinophil peroxidase, histologic evidence of inflammation, and increased expression levels of TNF-α, IL-6, and IL-8. pBD2 increased the expression of zonula occludens-1, zonula occludens-2, claudin-1, mucin-1, and mucin-2 mRNA and proteins, and it decreased permeability to FITC-D, as well as apoptosis, in DSS-treated mice. pBD2 also decreased inflammatory infiltrates of the colon epithelium. In Caco-2 cells, pBD2 increased transepithelial electrical resistance and mucin mRNA expression, and it decreased the permeability of FITC-D while preserving the structural integrity of the tight junctions. The effects of pBD2 appeared to be through upregulation of the expression of genes associated with tight junctions and mucins, and by suppressing DSS-induced increases in inflammation, inducible NO synthase, cyclooxygenase-2, and apoptosis. These results show that pBD2 improves DSS-induced changes in mucosal lesions and paracellular permeability, possibly by affecting the activation of NF-κB signaling. The present study demonstrates that intrarectal administration of pBD2 may be a novel preventive option for ulcerative colitis.

Human antimicrobial peptides and proteins

As the key components of innate immunity, human host defense antimicrobial peptides and proteins (AMPs) play a critical role in warding off invading microbial pathogens. In addition, AMPs can possess other biological functions such as apoptosis, wound healing, and immune modulation. This article provides an overview on the identification, activity, 3D structure, and mechanism of action of human AMPs selected from the antimicrobial peptide database. Over 100 such peptides have been identified from a variety of tissues and epithelial surfaces, including skin, eyes, ears, mouths, gut, immune, nervous and urinary systems. These peptides vary from 10 to 150 amino acids with a net charge between -3 and +20 and a hydrophobic content below 60%. The sequence diversity enables human AMPs to adopt various 3D structures and to attack pathogens by different mechanisms. While α-defensin HD-6 can self-assemble on the bacterial surface into nanonets to entangle bacteria, both HNP-1 and β-defensin hBD-3 are able to block cell wall biosynthesis by binding to lipid II. Lysozyme is well-characterized to cleave bacterial cell wall polysaccharides but can also kill bacteria by a non-catalytic mechanism. The two hydrophobic domains in the long amphipathic α-helix of human cathelicidin LL-37 lays the basis for binding and disrupting the curved anionic bacterial membrane surfaces by forming pores or via the carpet model. Furthermore, dermcidin may serve as ion channel by forming a long helix-bundle structure. In addition, the C-type lectin RegIIIα can initially recognize bacterial peptidoglycans followed by pore formation in the membrane. Finally, histatin 5 and GAPDH(2-32) can enter microbial cells to exert their effects. It appears that granulysin enters cells and kills intracellular pathogens with the aid of pore-forming perforin. This arsenal of human defense proteins not only keeps us healthy but also inspires the development of a new generation of personalized medicine to combat drug-resistant superbugs, fungi, viruses, parasites, or cancer. Alternatively, multiple factors (e.g., albumin, arginine, butyrate, calcium, cyclic AMP, isoleucine, short-chain fatty acids, UV B light, vitamin D, and zinc) are able to induce the expression of antimicrobial peptides, opening new avenues to the development of anti-infectious drugs.