Efficient in planta production of amidated antimicrobial peptides that are active against drug-resistant ESKAPE pathogens.

Antimicrobial peptides (AMPs) are promising next-generation antibiotics that can be used to combat drug-resistant pathogens. However, the high cost involved in AMP synthesis and their short plasma half-life render their clinical translation a challenge. To address these shortcomings, we report efficient production of bioactive amidated AMPs by transient expression of glycine-extended AMPs in Nicotiana benthamiana line expressing the mammalian enzyme peptidylglycine α-amidating mono-oxygenase (PAM). Cationic AMPs accumulate to substantial levels in PAM transgenic plants compare to nontransgenic N. benthamiana. Moreover, AMPs purified from plants exhibit robust killing activity against six highly virulent and antibiotic resistant ESKAPE pathogens, prevent their biofilm formation, analogous to their synthetic counterparts and synergize with antibiotics. We also perform a base case techno-economic analysis of our platform, demonstrating the potential economic advantages and scalability for industrial use. Taken together, our experimental data and techno-economic analysis demonstrate the potential use of plant chassis for large-scale production of clinical-grade AMPs.

Construction of a Tandem Repeat Peptide Sequence with Pepsin Cutting Sites to Produce Recombinant α-Melanocyte-Stimulating Hormone.

The production of α-melanocyte-stimulating hormone (α-MSH), a peptide hormone composed of 13 amino acids, is attempted by recombinant expression using E. coli as the host. To achieve this aim, a synthetic gene containing eight tandem repeats of msh gene (8msh) was designed for ribosomal synthesis of 8 α-MSH. The merit of the strategy is to diminish the peptide toxicity against the host cell and to achieve a higher production yield. Pepsin cleavage sites are introduced between the peptides for enzymatic proteolysis to obtain the monomeric peptide of α-MSH. The constructed plasmid was transformed into different strains of E. coli hosts, and E. coli XL1-Blue with gene 8msh revealed the highest yield of 8 α-MSH. Although 8 α-MSH was fractionalized in the insoluble pellets after cell lysis, pepsin cleavage was able to produce soluble α-MSH peptide, as analyzed and confirmed by mass spectrometry and peptide activity assays. The production of α-MSH was quantified using HPLC with a yield of 42.9 mg/L of LB culture. This study demonstrates the feasibility of producing α-MSH using recombinant expression of tandem repeat gene. The production procedure involves minimal post-treatment and processing and can be scaled up for industrial application.

Stress-Inducible Gene Atf3 Dictates a Dichotomous Macrophage Activity in Chemotherapy-Enhanced Lung Colonization.

Previously, we showed that chemotherapy paradoxically exacerbated cancer cell colonization at the secondary site in a manner dependent on Atf3, a stress-inducible gene, in the non-cancer host cells. Here, we present evidence that this phenotype is established at an early stage of colonization within days of cancer cell arrival. Using mouse breast cancer models, we showed that, in the wild-type (WT) lung, cyclophosphamide (CTX) increased the ability of the lung to retain cancer cells in the vascular bed. Although CTX did not change the WT lung to affect cancer cell extravasation or proliferation, it changed the lung macrophage to be pro-cancer, protecting cancer cells from death. This, combined with the initial increase in cell retention, resulted in higher lung colonization in CTX-treated than control-treated mice. In the Atf3 knockout (KO) lung, CTX also increased the ability of lung to retain cancer cells. However, the CTX-treated KO macrophage was highly cytotoxic to cancer cells, resulting in no increase in lung colonization-despite the initial increase in cell retention. In summary, the status of Atf3 dictates the dichotomous activity of macrophage: pro-cancer for CTX-treated WT macrophage but anti-cancer for the KO counterpart. This dichotomy provides a mechanistic explanation for CTX to exacerbate lung colonization in the WT but not Atf3 KO lung.

Ultraviolet radiation, vitamin D, and COVID-19.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19), has become pandemic on March 11th, 2020. COVID-19 has a range of symptoms that includes fever, fatigue, dry cough, aches, and labored breathing to acute respiratory distress and possibly death. Health systems and hospitals have been completely rearranged since March 2020 in order to limit the high rate of virus spreading. Hence, a great debate on deferrable visits and treatments including phototherapy for skin diseases is developing. In particular, as regards phototherapy very few data are currently available regarding the chance to continue it, even if it may be a useful resource for treating numerous dermatological patients. However, phototherapy has an immunosuppressive action possibly facilitating virus infection. In the context of COVID-19 infection risk it is important to pointed out whether sunlight, phototherapy and in particular ultraviolet radiation (UV-R) constitute or not a risk for patients. In this review we aimed to focus on the relationship between UV-R, sunlight, phototherapy, and viral infections particularly focusing on COVID-19.

Toll-like receptor activation of equine mesenchymal stromal cells to enhance antibacterial activity and immunomodulatory cytokine secretion.

OBJECTIVE: To evaluate effects of Toll-like and nucleotide-binding oligomerization domain (NOD)-like receptor (TLR, NLR) ligand stimulation of equine mesenchymal stromal cells (MSCs) on antibacterial and immunomodulatory properties in vitro. STUDY DESIGN: Controlled laboratory study. SAMPLE POPULATION: Equine bone-marrow-derived MSCs (three horses). METHODS: MSCs were stimulated with TLR (polyinosinic:polycytidylic acid [pIC] and lipopolysaccharide [LPS]) and NLR agonists (γ-d-Glu-mDAP [IE-DAP]) for 2 h, and plated at 1 × 105 cells/well 24 h. MSC-conditioned media (MSC-CM) were collected and assessed for antimicrobial peptide cathelicidin/LL-37 production, bactericidal action against multidrug-resistant planktonic and biofilm Staphylococcus aureus and neutrophil phagocytosis. Bacterial growth was measured by plating bacteria and counting viable colonies, reading culture absorbance, and live-dead staining with confocal microscopy imaging. Following initial comparison of activating stimuli, TLR3-agonist pIC protocols (cell density during activation and plating, culture time, %serum) were further optimized for bactericidal activity and secretion of interleukin-8 (IL-8), monocyte-chemoattractant-protein (MCP-1), and cathelicidin/LL37. RESULTS: MSCs stimulation with pIC (p = .004) and IE-DAP (p = .03) promoted increased bactericidal activity, evidenced by reduced viable planktonic colony counts. PIC stimulation (2 × 106 cells/ml, 2 h, 10 µg/ml) further suppressed biofilm formation (p = .001), enhanced neutrophil bacterial phagocytosis (p = .009), increased MCP-1 secretion (p < .0001), and enhanced cathelicidin/LL-37 production, which was apparent when serum concentration in media was reduced to 1% (p = .01) and 2.5% (p = .05). CONCLUSION: TLR-3 pIC MSCs activation was most effective to enhance antibacterial and cytokine responses, which were affected by serum reduction. CLINICAL SIGNIFICANCE: In vitro TLR-3 activation of equine MSCs tested here may be a strategy to improve antibacterial properties of MSCs to treat antibiotic-resistant infections.

Steroid hormone modulates the production of cathelicidin and human ß-defensins in lung epithelial cells and macrophages promoting Mycobacterium tuberculosis killing.

Several studies have documented the interaction between the immune and endocrine systems as an effective defense strategy against tuberculosis, involving the production of several molecules and immunological processes. In this study, we determined the effect of cortisol and dehydroepiandrosterone (DHEA) on the production of antimicrobial peptides such as cathelicidin and human ß-defensin (HBD) -2, and HBD-3 and their effect on intracellular growth of Mycobacterium tuberculosis (Mtb) in lung epithelial cells and macrophages. Our results showed that DHEA promotes the production of these antimicrobial peptides in infected cells, correlating with the decrease of Mtb bacilli loads. These results suggest the use of exogenous DHEA as an adjuvant for tuberculosis therapy.

Promiscuous Installation of d-Amino Acids in Gene-Encoded Peptides.

d-Amino acids can have major effects on the structure, proteolytic stability, and bioactivity of peptides. Proteusin radical S-adenosyl methionine epimerases regioselectively install such residues in ribosomal peptides to generate peptides with the largest number of d-residues currently known in biomolecules. To study their utility in synthetic biology, we investigated the substrate tolerance and substrate-product relationships of the cyanobacterial model epimerase OspD using libraries of point mutants as well as distinct extended peptides that were fused to an N-terminal leader sequence. OspD was found to exhibit exceptional substrate promiscuity in E. coli, accepting 15 different amino acids and converting peptides with a broad range of compositions, secondary structures, and polarities. Diverse single and multiple epimerization patterns were identified that were dictated by the peptide sequence. The data suggest major potential in creating genetically encoded products previously inaccessible by synthetic biology.

IL-33 synergistically promotes the proliferation of lung cancer cells in vitro by inducing antibacterial peptide LL-37 and proinflammatory cytokines in macrophages.

Lung cancer is the primary cause of cancer-related deaths, and the persistent inflammation is inextricably linked with the lung cancer tumorigenesis. Pro-inflammatory cytokine interleukin-33 (IL-33) is able to serve as a potent modulator of cancer. Mounting evidence indicates IL-33 has significant effect on lung cancer progression by regulating host immune response, but the current opinions about the function and mechanism of IL-33 in lung cancer are still controversial. Meanwhile, antibacterial peptide LL-37 also exerts a momentous effect on immune responses to lung cancer. LL-37 is regarded as versatile, including antimicrobial activities, chemotaxis and immunoregulation. However, the immunomodulatory mechanism of IL-33 and LL-37 in lung cancer remains thoroughly not defined. Here, we determined the secretion of LL-37 was up-regulated in lung cancer serum samples. Similarly, the expression of CRAMP was enhancive in macrophages after co-cultured with lung cancer cells. Moreover, we expounded that IL-33 could up-regulate LL-37 secretion in macrophages, resulting in the massive releases of IL-6 and IL-1ß. Additionally, LL-37 cooperated with IL-33 to increase the phosphorylation of p38 MAPK and NF-κB p65 pathways, and augmented IL-6 and IL-1ß secretion, which resulting in the proliferation of lung cancer cells in vitro. In conclusion, our study identified that IL-33 aggravated the inflammation of lung cancer by increasing LL-37 expression in macrophages, thereby promoting lung cancer cell proliferation in vitro. It is contributed to our present understanding of the immunomodulatory relationship between pro-inflammatory cytokines and antibacterial peptides in the tumor immune response, and offer a novel perspective for controlling the progress of lung cancer.

MiR-196-5p involvement in selenium deficiency-induced immune damage via targeting of NFκBIA in the chicken trachea.

Dietary selenium (Se) deficiency can induce multifarious immune injury in tissues, accompanied by inflammation and a decreased expression of selenoproteins. The results of previous studies indicated that these issues are associated with Se-mediated microRNAs involved in immune regulation, although the specific mechanisms associated with these interactions have not been reported in the trachea of chickens. To explore the effects of Se deficiency in the trachea of chickens and the role of miR-196-5p, we established correlational models of tracheal injury in chickens. One hundred broilers were divided into four groups, including a control group (C group), a Se deficient group (L group), a lipopolysaccharide (LPS)-induced control group (C + LPS group) and a LPS-induced Se deficient group (L + LPS group). Light microscopy observations indicated that the infiltration of inflammatory cells was the major histopathological change caused by Se deficiency. Furthermore, ultrastructural observation of the tracheal epithelium and ciliary showed typical inflammatory signs owing to Se deficiency. We determined the targeting relationship between miR-196-5p and NFκBIA by bioinformatics analysis. In the case of Se deficiency, the changes were detected as follows: 19 selenoproteins showed different degrees of decrease (p < 0.05). Significant inhibition of both antimicrobial peptides and immunoglobulin production were observed (p < 0.05). IκB-α (NFκBIA) expression degraded with the increasing miR-196-5p (p < 0.05), and the NF-κB pathway was activated. Thereafter, we can see a significant increase in the mRNA levels of inflammatory cytokines-related genes (tumor necrosis factor (TNF)-α, inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2, prostaglandin E (PTGE), interleukin (IL)-1ß, IL-6) and protein expression of NF-κB/iNOS pathway-related genes (NF-κB, iNOS, TNF-α, COX-2) (p < 0.05). The release of IL-2, interferon (IFN)-γ inhibited (p < 0.05) and the secretion of IL-4, IL-6 increased, suggesting the imbalance of Th1/Th2 (Th, helper T cell) cytokines. Compared to the control, the mRNA and protein expression levels of the anti-inflammatory system components with antioxidant activity (PPAR-γ/HO-1) were in an inhibitory state (p < 0.05). Antioxidases (SOD, CAT, GSH-Px) activities were suppressed. The activities of the peroxide markers (MDA, H2O2) were enhanced (p < 0.05). In addition, Se deficiency had a positive effect on the pathological changes of inflammation and the exceptional immunity in LPS-treated groups (p < 0.05). The results confirmed the relationship between miR-196-5p and NFκBIA in chickens, revealing that Se deficiency causes respiratory mucosal immune dysfunction via the miR-196-5p-NFκBIA axis, oxidative stress and inflammation. Moreover, Se deficiency exacerbates the inflammatory damage stimulated by LPS. Our work provides a theoretical basis for the prevention of tracheal injury owing to Se deficiency and can be used as a reference for comparative medicine. Furthermore, the targeted regulation of miR-196-5p and NFκBIA may contribute to the protection of the tracheal mucosa in chickens.

Does the Future of Antibiotics Lie in Secondary Metabolites Produced by Xenorhabdus spp.? A Review.

The over-prescription of antibiotics for treatment of infections is primarily to blame for the increase in bacterial resistance. Added to the problem is the slow rate at which novel antibiotics are discovered and the many processes that need to be followed to classify antimicrobials safe for medical use. Xenorhabdus spp. of the family Enterobacteriaceae, mutualistically associated with entomopathogenic nematodes of the genus Steinernema, produce a variety of antibacterial peptides, including bacteriocins, depsipeptides, xenocoumacins and PAX (peptide antimicrobial-Xenorhabdus) peptides, plus additional secondary metabolites with antibacterial and antifungal activity. The secondary metabolites of some strains are active against protozoa and a few have anti-carcinogenic properties. It is thus not surprising that nematodes invaded by a single strain of a Xenorhabdus species are not infected by other microorganisms. In this review, the antimicrobial compounds produced by Xenorhabdus spp. are listed and the gene clusters involved in synthesis of these secondary metabolites are discussed. We also review growth conditions required for increased production of antimicrobial compounds.

Maltose Induced Expression of Cecropin AD by SUMO Technology in Bacillus subtilis WB800N.

Cecropin AD (CAD) is a hybrid peptide composed of 37 amino acids with the characters of strong antibacterial, antitumor properties and no hemolytic activity, which was regarded as a promising antibiotic candidate. Thus, a safe method to produce Cecropin AD is necessary to be found. In the study, Bacillus subtilis WB800N was employed as host strain. The CAD coding sequence fused with the signal peptide of SPsacB, the 6 × His gene and the gene of small ubiquitin-like modifier were cloned into the maltose-inducible vector pGJ148. Under the induction by 6% maltose, the recombinant fusion protein was successfully expressed and detected in culture substrate. An optimized amount (26.4 mg/L) of the recombinant CAD was purified of culture supernatant. After purification and digestion, the recombinant CAD was harvested about 4.5 mg/L with a purity of 93%. Recombinant CAD exhibited similar antimicrobial activity with synthetic CAD. This shows that the production of CAD in maltose-induced Bacillus subtilis expression system is a relatively safe method, which is vital for the application of CAD in animal husbandry production.

A Type IIa crustin from the pink shrimp Farfantepenaeus paulensis (crusFpau) is constitutively synthesized and stored by specific granule-containing hemocyte subpopulations.

Crustins are cysteine-rich antimicrobial peptides (AMPs) widely distributed across crustaceans. From the four described crustin Types (I to IV), crustins from the subtype IIa are the most abundant and diverse members found in penaeid shrimp. Despite the critical role of Type IIa crustins in shrimp antimicrobial defenses, there is still limited information about their synthesis and antimicrobial properties. Here, we report the subcellular localization and the antibacterial spectrum of crusFpau, a Type IIa crustin from the pink shrimp Farfantepenaeus paulensis. The recombinantly expressed crusFpau showed antimicrobial activity against both Gram-positive and Gram-negative bacteria at low concentrations. Results from immunofluorescence using anti-rcrusFpau antiserum revealed that crusFpau is synthetized and stored by both granular and semigranular hemocytes, but not by hyaline cells. Interestingly, not all granular and semigranular hemocytes stained for crusFpau, revealing that this crustin is produced by specific granule-containing hemocyte subpopulations. Finally, we showed that the granule-stored peptides are not constitutively secreted into the plasma of healthy animals.

Protective effects of seaweed supplemented diet on antioxidant and immune responses in European seabass (Dicentrarchus labrax) subjected to bacterial infection.

European seabass (Dicentrarchus labrax) production is often hampered by bacterial infections such as photobacteriosis caused by Photobacterium damselae subsp. piscicida (Phdp). Since diet can impact fish immunity, this work investigated the effect of dietary supplementation of 5% Gracilaria sp. aqueous extract (GRA) on seabass antioxidant capacity and resistance against Phdp. After infection, mortality was delayed in fish fed GRA, which also revealed increased lysozyme activity levels, as well as decreased lipid peroxidation, suggesting higher antioxidant capacity than in fish fed a control diet. Dietary GRA induced a down-regulation of hepatic stress-responsive heat shock proteins (grp-78, grp-170, grp-94, grp-75), while bacterial infection caused a down-regulation in antioxidant genes (prdx4 and mn-sod). Diet and infection interaction down-regulated the transcription levels of genes associated with oxidative stress response (prdx5 and gpx4) in liver. In head-kidney, GRA led to an up-regulation of genes associated with inflammation (il34, ccr9, cd33) and a down-regulation of genes related to cytokine signalling (mif, il1b, defb, a2m, myd88). Additionally, bacterial infection up-regulated immunoglobulins production (IgMs) and down-regulated the transcription of the antimicrobial peptide leap2 in head kidney. Overall, we found that GRA supplementation modulated seabass resistance to Phdp infection.

A novel nuclear factor Akirin regulating the expression of antimicrobial peptides in Chinese mitten crab Eriocheir sinensis.

Akirin, a recently discovered nuclear factor, participates in regulating various processes, including cell proliferation and differentiation, embryonic development, and immunity. In the present study, a novel Akirin was identified from Chinese mitten crab Eriocheir sinensis (designated as EsAkirin), and its primary functions in regulating antimicrobial peptides were explored. The open reading frame of EsAkirin was of 615 bp, encoding a polypeptide of 204 amino acid residues. The deduced amino acid sequence of EsAkirin shared high similarities ranging from 44.1% to 89.2% with other Akirins. In the phylogenetic tree, EsAkirin was firstly clustered with Akirins from shrimp and then assigned into the invertebrate branch. The mRNA transcripts of EsAkirin were constitutively expressed in all the tested tissues, with the highest expression level (5.07-fold compared to the stomach, p < 0.01) in hepatopancreas. The mRNA expression of EsAkirin in hemocytes was significantly increased at 6 h, and reached the maximum level at 24 h post stimulations with either lipopolysaccharide (LPS) (5.04-fold, p < 0.01) or Aeromonas hydrophila (3.10-fold, p < 0.01). After the injection of EsAkirin-dsRNA, the mRNA expressions of EsALF2, EsLYZ, EsCrus2 and EsDWD1 were significantly decreased (p < 0.01) upon LPS stimulation. EsAkirin protein was prominently distributed in the nucleus of E. sinensis hemocytes after LPS and A. hydrophila stimulations. The relative luciferase reporter system analysis revealed that the activity of nuclear factor-κB was significantly up-regulated (2.64-fold, p < 0.01) in human embryonic kidney (HEK293T) cells after the over-expression of EsAkirin. Collectively, these results suggested that EsAkirin might play an important role in the immune responses of E. sinensis by regulating the expression of antimicrobial peptides.

Venoms of Iranian Scorpions (Arachnida, Scorpiones) and Their Potential for Drug Discovery.

Scorpions, a characteristic group of arthropods, are among the earliest diverging arachnids, dating back almost 440 million years. One of the many interesting aspects of scorpions is that they have venom arsenals for capturing prey and defending against predators, which may play a critical role in their evolutionary success. Unfortunately, however, scorpion envenomation represents a serious health problem in several countries, including Iran. Iran is acknowledged as an area with a high richness of scorpion species and families. The diversity of the scorpion fauna in Iran is the subject of this review, in which we report a total of 78 species and subspecies in 19 genera and four families. We also list some of the toxins or genes studied from five species, including Androctonus crassicauda, Hottentotta zagrosensis, Mesobuthus phillipsi, Odontobuthus doriae, and Hemiscorpius lepturus, in the Buthidae and Hemiscorpiidae families. Lastly, we review the diverse functions of typical toxins from the Iranian scorpion species, including their medical applications.

Duodenal expression of antimicrobial peptides in dogs with idiopathic inflammatory bowel disease and intestinal lymphoma.

Although antimicrobial peptides (AMPs) play an integral role in the regulation of intestinal microbiota and homeostasis, their expression in canine gastrointestinal diseases, including idiopathic inflammatory bowel disease (IBD) and intestinal lymphoma, remains unknown. The objective of this study was to investigate the intestinal expression of AMPs in dogs with IBD or intestinal lymphoma. IBD was diagnosed in 44 dogs, small cell intestinal lymphoma in 25 dogs, and large cell intestinal lymphoma in 19 dogs. Twenty healthy beagles were used as normal controls. Duodenal mRNA expression of six representative AMPs - lactoferrin, lysozyme, cathelicidin, secretory leukocyte peptidase inhibitor (SLPI), bactericidal/permeability increasing protein (BPI), and canine beta defensin (CBD103) - was quantified by real-time reverse transcription polymerase chain reaction. The relative expression of BPI, lactoferrin, and SLPI was significantly higher in dogs with IBD and intestinal lymphomas than in healthy controls. Interestingly, the expression patterns of AMPs differed between dogs with IBD and those with intestinal lymphomas, especially small cell lymphoma. Increased expression of BPI differentiated IBD from dogs with small cell intestinal lymphoma, with a sensitivity of 93.2%, a specificity of 100%, and an area under the curve of 0.955. These results suggest that the expression patterns of AMP aid in the diagnosis of canine IBD and intestinal lymphoma, although it remains uncertain whether the altered AMP expression is the cause or effect of mucosal inflammation.

Role of Lipid Composition, Physicochemical Interactions, and Membrane Mechanics in the Molecular Actions of Microbial Cyclic Lipopeptides.

Several experimental and theoretical studies have extensively investigated the effects of a large diversity of antimicrobial peptides (AMPs) on model lipid bilayers and living cells. Many of these peptides disturb cells by forming pores in the plasma membrane that eventually lead to the cell death. The complexity of these peptide-lipid interactions is mainly related to electrostatic, hydrophobic and topological issues of these counterparts. Diverse studies have shed some light on how AMPs act on lipid bilayers composed by different phospholipids, and how mechanical properties of membranes could affect the antimicrobial effects of such compounds. On the other hand, cyclic lipopeptides (cLPs), an important class of microbial secondary metabolites, have received comparatively less attention. Due to their amphipathic structures, cLPs exhibit interesting biological activities including interactions with biofilms, anti-bacterial, anti-fungal, antiviral, and anti-tumoral properties, which deserve more investigation. Understanding how physicochemical properties of lipid bilayers contribute and determining the antagonistic activity of these secondary metabolites over a broad spectrum of microbial pathogens could establish a framework to design and select effective strategies of biological control. This implies unravelling-at the biophysical level-the complex interactions established between cLPs and lipid bilayers. This review presents, in a systematic manner, the diversity of lipidated antibiotics produced by different microorganisms, with a critical analysis of the perturbing actions that have been reported in the literature for this specific set of membrane-active lipopeptides during their interactions with model membranes and in vivo. With an overview on the mechanical properties of lipid bilayers that can be experimentally determined, we also discuss which parameters are relevant in the understanding of those perturbation effects. Finally, we expose in brief, how this knowledge can help to design novel strategies to use these biosurfactants in the agronomic and pharmaceutical industries.

Protecting intestinal epithelial cells against deoxynivalenol and E. coli damage by recombinant porcine IL-22.

Pigs suffer enteritis induced by pathogenic bacteria infection and toxins in the moldy feed, which cause intestinal epithelial damage and diarrhea through the whole breeding cycle. Interleukin-22 (IL-22) plays a critical role in maintaining intestinal mucosal barrier function through repairing intestinal epithelial damage. However, little was known about the effects of IL-22 against apoptosis caused by toxins and infection of intestinal pathogens in the intestinal epithelium, especially in pigs. In this study, we had successfully used prokaryotic expression system to produce recombinant porcine interleukin-22. Meanwhile, purified rIL-22 could activate STAT3 signal pathway and have been demonstrated to be safe to IPEC-J2 cells by increasing E-cadherin expression, without proinflammatory cytokines changes. Furthermore, rIL-22 reversed apoptosis induced by deoxynivalenol (DON) and played a vital part in repairing the intestinal injury. We also found that rIL-22 stimulated epithelial cells to secrete pBD-1 against enterotoxigenic E. coli (ETEC) K88 infection, as well as alleviating apoptosis ratio. This study provided a theoretical basis for curing intestinal inflammation caused by ETEC infection and epithelial apoptosis induced by DON with rIL-22 in pigs.

4-Hydroxybutyrate Promotes Endogenous Antimicrobial Peptide Expression in Macrophages.

IMPACT STATEMENT: This study evaluated the biological activity of hydroxylated derivatives of butyrate as inductors of antimicrobial peptides (AMPs) in murine bone marrow-derived macrophages in vitro. A differential modulation of AMP expression by the hydroxylated derivatives of butyrate is shown. The ability of sodium 4-hydroxybutyrate to upregulate AMP expression through a histone deacetylase inhibitory-independent mechanism, and to promote increased resistance to bacterial contamination in vivo are also shown. The findings provide an alternative for prevention of bacterial contamination of implanted biomaterials. Functionalization of biomaterials with hydroxylated derivatives of butyrate can enhance the endogenous antimicrobial activity of the immune system through increased production of AMPs by host cells, thus providing protection against bacterial contamination.

Statins influence epithelial expression of the anti-microbial peptide LL-37/hCAP-18 independently of the mevalonate pathway.

Anti-microbial resistance increases among bacterial pathogens and new therapeutic avenues needs to be explored. Boosting innate immune mechanisms could be one attractive alternative in the defence against infectious diseases. The cholesterol-lowering drugs, statins, have been demonstrated to also affect the immune system. Here we investigate the effect of statins on the expression of the human cathelicidin anti-microbial peptide (CAMP) LL-37/hCAP-18 [encoded by the CAMP gene] and explore the underlying mechanisms in four epithelial cell lines of different origin. Simvastatin induced CAMP expression in bladder epithelial cells telomerase-immortalized uroepithelial cells (TERT-NHUCs), intestinal cells HT-29 and keratinocytes HEKa, but not in airway epithelial cells A549. Gene induction in HEKa cells was reversible by mevalonate, while this effect was independent of the cholesterol biosynthesis pathway in TERT-NHUCs. Instead, inhibition of histone deacetylases by simvastatin seems to be involved. For HT-29 cells, both mechanisms may contribute. In addition, simvastatin increased transcription of the vitamin D-activating enzyme CYP27B1 which, in turn, may activate LL-37/hCAP-18 production. Taken together, simvastatin is able to promote the expression of LL-37/hCAP-18, but cell line-specific differences in efficacy and the involved signalling pathways exist.