Toll-like receptors as key mediators in innate antifungal immunity

Toll Like Receptors Promote High Glucose-Induced Vascular Endothelial Cell Dysfunction by Regulating Neutrophil Extracellular Traps Formation

Diabetic retinopathy (DR) is a major cause of blindness globally. Neutrophils and neutrophil extracellular traps (NETs) are believed to play a role in the development of DR. However, the specific contribution of NETs to hyperglycemia-induced vascular endothelial cell dysfunction remains unclear. In this study, we cocultured high glucose-activated neutrophils (HGNs) with human umbilical vein endothelial cells (HUVECs) to investigate the role of NETs in high glucose-induced HUVEC dysfunction. Our findings indicate that high glucose levels promote NETs formation, which can be inhibited by a toll-like receptor (TLR) 2 antagonist and a TLR4 antagonist. It was observed that reactive oxygen species production plays a role in TLR2- but not TLR4-mediated NETs formation. Additionally, HGNs were found to promote HUVEC proliferation through phagocytosis rather than NETs. We also discovered that NETs contribute to high glucose-induced HUVEC dysfunction by enhancing neutrophil-HUVEC adhesion, inhibiting HUVEC migration, and compromising the barrier function of the cells by reducing zonula occludens-1 expression. This dysfunction could be partially mitigated by TLR2 and TLR4 antagonists. In conclusion, high glucose stimulates NETs formation, leading to vascular endothelial cell damage, and TLRs may facilitate high glucose-induced endothelial dysfunction by modulating NETs formation.

From defense to offense: Modulating toll-like receptors to combat arbovirus infections

Arboviruses are a significant threat to global public health, with outbreaks occurring worldwide. Toll-like receptors (TLRs) play a crucial role in the innate immune response against these viruses by recognizing pathogen-associated molecular patterns and initiating an inflammatory response. Significantly, TLRs commonly implicated in the immune response against viral infections include TLR2, TLR4, TLR6, TLR3, TLR7, and TLR8; limiting or allowing them to replicate and spread within the host. Modulating TLRs has emerged as a promising approach to combat arbovirus infections. This review summarizes recent advances in TLR modulation as a therapeutic target in arbovirus infections. Studies have shown that the activation of TLRs can enhance the immune response against arbovirus infections, leading to increased viral clearance and protection against disease. Conversely, inhibition of TLRs can reduce the excessive inflammation and tissue damage associated with arbovirus infection. Modulating TLRs represents a potential therapeutic strategy to combat arbovirus infections.

Nonspecific lipid-transfer proteins trigger TLR2 and NOD2 signaling and undergo ligand-dependent endocytosis in epithelial cells

BACKGROUND

Allergens can cross the epithelial barrier to enter the body but how this cellular passage affects protein structures and the downstream interactions with the immune system are still open questions.

OBJECTIVE

We sought to show the molecular details and the effects of 3 nonspecific lipid transfer proteins (nsLTPs; Mal d 3 [allergenic nsLTP1 from apple], Cor a 8 [allergenic nsLTP1 from hazelnut], and Pru p 3 [allergenic nsLTP1 from peach]) on epithelial cell uptake and transport.

METHODS

We used fluorescent imaging, flow cytometry, and proteomic and lipidomic screenings to identify the mechanism involved in nsLTP cellular uptake and signaling on selected epithelial and transgenic cell lines.

RESULTS

nsLTPs are transported across the epithelium without affecting cell membrane stability or viability, and allergen uptake was largely impaired by inhibition of clathrin-mediated endocytosis. Analysis of the lipidome associated with nsLTPs showed a wide variety of lipid ligands predicted to bind inside the allergen hydrophobic cavity. Importantly, the internalization of nsLTPs was contingent on these ligands in the protein complex. nsLTPs were found to initiate cellular signaling via Toll-like receptor 2 but not the cluster of differentiation 1 protein receptor, despite neither being essential for nsLTP endocytosis. We also provide evidence that the 3 allergens induced intracellular stress signaling through activation of the NOD2 pathway.

CONCLUSIONS

Our work consolidates the current model on nsLTP-epithelial cell interplay and adds molecular details about cell transport and signaling. In addition, we have developed a versatile toolbox to extend these investigations to other allergens and cell types.

Structural properties, bioactivities, structure-activity relationships and bio-applications of polysaccharides from Auricularia auricula: A review

Auricularia auricula (A. auricula), is a medicinal and edible fungus in China for thousands of years with rich nutrition and delicious taste. The main active ingredient of A. auricula is polysaccharide, which has antitumor, hypoglycemic, antioxidant, and immune regulation bioactivities. It is widely recognized that the biological activity of polysaccharides is closely related to the chemical structure and advanced structure. In terms of polysaccharides extracted from A. auricula (AAPs), there were distinguished structures reported due to the different original resources and extraction methods, leading to various bioactivities. However, the structure-activity relationship of AAPs has scarcely been reviewed till now. In addition, polysaccharides were found to have specific self-assembly properties recently, together with their bioactivities, endowing them with unique physicochemical properties. Nowadays, an increasing number of polysaccharides, such as cellulose, chitin, and pectin, have been used to construct various functional materials in the fields of food, cosmetics, and biomedical materials. Therefore, the construction of functional materials by AAPs is of great research significance. This article aims to provide a systematic review of the structure-activity relationship of AAPs and summarize the functional materials constructed based on AAPs to provide theoretical references for further research and application of AAPs.

The role of platelets in central hubs of inflammation: A literature review

Platelets are increasingly recognized for their multifaceted roles in inflammation beyond their traditional involvement in haemostasis. This review consolidates knowledge on platelets as critical players in inflammatory responses. This study did an extensive search of electronic databases and identified studies on platelets in inflammation, focusing on molecular mechanisms, cell interactions, and clinical implications, emphasizing recent publications. Platelets contribute to inflammation via surface receptors, release of mediators, and participation in neutrophil extracellular trap formation. They are implicated in diseases like atherosclerosis, rheumatoid arthritis, and sepsis, highlighting their interaction with immune cells as pivotal in the onset and resolution of inflammation. Platelets are central to regulating inflammation, offering new therapeutic targets for inflammatory diseases. Future research should explore specific molecular pathways of platelets in inflammation for therapeutic intervention.

Functional immune boosters; the herb or its dead microbiome? Antigenic TLR4 agonist MAMPs found in 65 medicinal roots and algae's

Background

Humans have been consuming medicinal plants (as herbs/ spices) to combat illness for centuries while ascribing beneficial effects predominantly to the plant/phytochemical constituents, without recognizing the power of obligatory resident microorganism' communities (MOCs) (live/dead bacteria, fungus, yeast, molds etc.) which remain after industrial microbial reduction methods. Very little is known about the taxonomic identity of residual antigenic microbial associated molecular patterns (MAMPs) debris in our botanical over the counter (OTC) products, which if present would be recognized as foreign (non-self) antigenic matter by host pattern recognition receptors (PRRs) provoking a host immune response; this the basis of vaccine adjuvants. As of today, only few research groups have removed the herbal MAMP biomass from herbs, all suggesting that immune activation may not be from the plant but rather its microbial biomass; a hypothesis we corroborate.

Purpose

The purpose of this work was to conduct a high through put screening (HTPS) of over 2500 natural plants, OTC botanical supplements and phytochemicals to elucidate those with pro-inflammatory; toll like receptor 4 (TLR4) activating properties in macrophages.

Study Design

The HTPS was conducted on RAW 264.7 cells vs. lipopolysaccharide (LPS) E. coli 0111:B4, testing iNOS / nitric oxide production ( NO 2 - ) as a perimeter endpoint. The data show not a single drug/chemical/ phytochemical and approximately 98 % of botanicals to be immune idle (not effective) with only 65 pro-inflammatory (hits) in a potency range of LPS. Method validation studies eliminated the possibility of false artifact or contamination, and results were cross verified through multiple vendors/ manufacturers/lot numbers by botanical species. Lead botanicals were evaluated for plant concentration of LPS, 1,3:1,6-β-glucan, 1,3:1,4-β-D-glucan and α-glucans; where the former paralleled strength in vitro. LPS was then removed from plants using high-capacity endotoxin poly lysine columns, where bioactivity of LPS null "plant" extracts were lost. The stability of E.Coli 0111:B4 in an acid stomach mimetic model was confirmed. Last, we conducted a reverse culture on aerobic plate counts (APCs) from select hits, with subsequent isolation of gram-negative bacteria (MacConkey agar). Cultures were 1) heat destroyed (retested/ confirming bioactivity) and 2) subject to taxonomical identification by genetic sequencing 18S, ITS1, 5.8 s, ITS2 28S, and 16S.

Conclusion

The data show significant gram negative MAMP biomass dominance in A) roots (e.g. echinacea, yucca, burdock, stinging nettle, sarsaparilla, hydrangea, poke, madder, calamus, rhaponticum, pleurisy, aconite etc.) and B) oceanic plants / algae's (e.g. bladderwrack, chlorella, spirulina, kelp, and "OTC Seamoss-blends" (irish moss, bladderwrack, burdock root etc), as well as other random herbs (eg. corn silk, cleavers, watercress, cardamom seed, tribulus, duckweed, puffball, hordeum and pollen). The results show a dominance of gram negative microbes (e.g. Klebsilla aerogenes, Pantoae agglomerans, Cronobacter sakazakii), fungus (Glomeracaea, Ascomycota, Irpex lacteus, Aureobasidium pullulans, Fibroporia albicans, Chlorociboria clavula, Aspergillus_sp JUC-2), with black walnut hull, echinacea and burdock root also containing gram positive microbial strains (Fontibacillus, Paenibacillus, Enterococcus gallinarum, Bromate-reducing bacterium B6 and various strains of Clostridium).

Conclusion

This work brings attention to the existence of a functional immune bioactive herbal microbiome, independent from the plant. There is need to further this avenue of research, which should be carried out with consideration as to both positive or negative consequences arising from daily consumption of botanicals highly laden with bioactive MAMPS.

The subversion of toll-like receptor signaling by bacterial and viral proteases during the development of infectious diseases

Toll-like receptors (TLRs) are pattern recognition receptors (PRRs) that respond to pathogen-associated molecular patterns (PAMPs). The recognition of specific microbial ligands by TLRs triggers an innate immune response and also promotes adaptive immunity, which is necessary for the efficient elimination of invading pathogens. Successful pathogens have therefore evolved strategies to subvert and/or manipulate TLR signaling. Both the impairment and uncontrolled activation of TLR signaling can harm the host, causing tissue destruction and allowing pathogens to proliferate, thus favoring disease progression. In this context, microbial proteases are key virulence factors that modify components of the TLR signaling pathway. In this review, we discuss the role of bacterial and viral proteases in the manipulation of TLR signaling, highlighting the importance of these enzymes during the development of infectious diseases.

BG34-200 Immunotherapy of Advanced Melanoma

High levels of myeloid-derived cells are characteristic of the tumor microenvironment (TME) of advanced melanoma. These cells interact with tumor cells to suppress the development of antitumor immune responses, regulate tumor metastasis, and drive cancer's resistance to virtually all types of therapy. Therefore, methods to disrupt tumor-associated myeloid cell function are actively being sought to find a cure. Our team has recently developed a plant-derived carbohydrate molecule, BG34-200, that modulates tumor-associated myeloid cells by targeting the cell surface receptor CD11b. In this study, we found that BG34-200 IV administration could significantly inhibit tumor growth and improve survival in B16F10 mice with advanced melanoma. Our data supported a model that the entry of BG34-200 into circulating melanoma tumor-associated inflammatory monocytes (TAIMs) could trigger a sequential immune activation: the BG34-200⁺ TAIM subsets migrated to tumor and differentiated into monocyte-derived dendritic cells (mo-DCs); then, the BG34-200⁺ mo-DCs migrated to tumor draining lymph nodes, where they triggered the generation of tumor-antigen-specific T cells. Based upon these results, we combined BG34-200 treatment with adoptive transfer of TdLN-derived T cells to treat advanced melanoma, which significantly improved animal survival and helped tumor-free survivors be resistant to a second tumor-cell challenge. The scientific findings from this study will allow us to develop new technology and apply BG34-200-based immunotherapy to patients with advanced melanoma who have not responded to current standard of care therapies with and without immunotherapy.

Use of Secondary Metabolites of Wood-Decaying Fungi to Reduce Damping off Disease

Phytopathogenic fungi can cause plant diseases that are difficult to control, including mass mortality of some tree species. The Fusarium oxysporum complex (sensu lato) is one of the most dangerous groups of phytopathogenic fungi, causing the death of conifer species, including Pinus sylvestris seedlings in forest and ornamental nurseries. Recently, non-chemical methods of plant protection have become the basis of integrated pest management (IPM) in the European Union (EC Directive). The possibility of protection of pine seedlings against the pathogen F. oxysporum using active substances from wood-destroying fungi commonly found in forests was examined. Methanolic extracts of Fomitopsis pinicola, Ganoderma applanatum, and Trametes versicolor were found to contain substances effective in both prevention and treatment of infected seedlings. G. applanatum and T. versicolor showed particular biological activity in increasing plant resistance. Efficacy, especially of the extract of F. pinicola, increased with concentration. Further field trials are needed to confirm the results obtained in laboratory tests on plant protection.

Inhibition of myeloid-derived suppressor cell arginase-1 production enhances T-cell-based immunotherapy against Cryptococcus neoformans infection

Cryptococcosis is a potentially lethal disease that is primarily caused by the fungus Cryptococcus neoformans, treatment options for cryptococcosis are limited. Here, we show glucuronoxylomannan, the major polysaccharide component of C. neoformans, induces the recruitment of neutrophilic myeloid-derived suppressor cells in mice and patients with cryptococcosis. Depletion of neutrophilic myeloid-derived suppressor cells enhances host defense against C. neoformans infection. We identify C-type lectin receptor-2d recognizes glucuronoxylomannan to potentiate the immunosuppressive activity of neutrophilic myeloid-derived suppressor cells by initiating p38-mediated production of the enzyme arginase-1, which inhibits T-cell mediated antifungal responses. Notably, pharmacological inhibition of arginase-1 expression by a specific inhibitor of p38, SB202190, or an orally available receptor tyrosine kinase inhibitor, vandetanib, significantly enhances T-cell mediated antifungal responses against cryptococcosis. These data reveal a crucial suppressive role of neutrophilic myeloid-derived suppressor cells during cryptococcosis and highlight a promising immunotherapeutic application by inhibiting arginase-1 production to combat infectious diseases.

Cryptococcus neoformans causes opportunistic infection and potentially lethal immunopathology but therapeutic options are limited. Here the authors implicate myeloid derived suppressor cells during C. neoformans infection and suggest targeting arginase-1 production as a potential therapeutic strategy.

Mannan-decorated pathogen-like polymeric nanoparticles as nanovaccine carriers for eliciting superior anticancer immunity

Using nanotechnology for cancer vaccine design holds great promise because of the intrinsic feature of nanoparticles in being captured by antigen-presenting cells (APCs). However, there are still obstacles in current nanovaccine systems in achieving efficient tumor therapeutic effects, which could partially be attributed to the unsatisfactory vaccine carrier design. Herein, we report a mannan-decorated pathogen-like polymeric nanoparticle as a protein vaccine carrier for eliciting robust anticancer immunity. This nanovaccine was constructed as a core-shell structure with mannan as the shell, polylactic acid-polyethylenimine (PLA-PEI) assembled nanoparticle as the core, and protein antigens and Toll-like receptor 9 (TLR9) agonist CpG absorbed onto the PLA-PEI core via electrostatic interactions. Compared to other hydrophilic materials, mannan decoration could greatly enhance the lymph node draining ability of the nanovaccine and promote the capturing by the CD8⁺ dendritic cells (DCs) in the lymph node, while PLA-PEI as the inner core could enhance antigen endosome escape thus promoting the antigen cross-presentation. In addition, mannan itself as a TLR4 agonist could synergize with CpG for maximally activating the DCs. Excitingly, we observed in several murine tumor models that using this nanovaccine alone could elicit robust immune response in vivo and result in superior anti-tumor effects with 50% of mice completely cured. This study strongly evidenced that mannan decoration and a rationally designed nanovaccine system could be quite robust in tumor vaccine therapy.

Elevated levels of interleukins, leukocyte protein and cathelicidin antimicrobial peptide are strongly associated with early to mid-stage of Pythium insidiosum infection in rabbit corneas

PURPOSE

Corneal infection in humans caused by Pythium insidiosum can lead to blindness and the host ocular immune response to it is less studied. Herein, we investigate the expression of mediators of innate and adaptive immune responses in a rabbit model.

METHODS

P. insidiosum zoospores were injected intracorneally in right eye of the nine New Zealand White rabbits while left eye was injected with 1XPBS. RT-qPCR and multiplex ELISA (mELISA) were used to study the expression of antimicrobial peptides (AMPs) and immune mediators in infected cornea on 3rd, 7^th and 9^th day of post-infection(PI). STRING-11.0 analysis was used to predict the interactions of immune mediators. mRNA expressions of pathogen recognition receptors (PRRs) were determined in human corneal epithelial cells (HCECs) stimulated with P. insidiosum zoospores. Data was analyzed using one-way ANOVA with Post-Hoc Tukey HSD test and p-value <0.05 was considered significant.

RESULTS

mRNA expression assay for IL-1β, IL-6, IL-8 and Cathelicidin antimicrobial peptide (CAP)-18 showed significant upregulation (p-value <0.05) on 7^thday post-infection (PI) compared to 3^rd and 9^thday while Leukocyte protein (LeukoP) was elevated significantly on 3^rd day followed by 7^th and 9^th day PI . Only IL-17A among other adaptive immune cytokines showed significant upregulation on 7^thday compared to 9^thday PI. Expressed in pg/mL, mELISA showed significant higher levels (p-value <0.05) of IL-1β, IL-8 in infected tissue in each of the time points compared to control. STRING analysis revealed co-expression of IL-1β, IL-8 and IL-6. Among PRRs, Dectin 1 and TLR4 showed significant upregulation in HCECs at 12hrs compared to 6hrs.

CONCLUSION

In the rabbit P. insidiosum keratitis model, innate immune mediators: IL-1β, IL-8, IL-6, AMPs: LeukoP and CAP-18 are strongly associated in early to mid-stage of corneal infection. Dectin 1 and TLR4 were observed to be associated with recognition of P. insidiosum.

A Model in Female Rats With Phenotypic Features Similar to Interstitial Cystitis/Bladder Pain Syndrome

This report describes methodological and exploratory investigations of the zymosan-induced neonatal bladder inflammation (NBI) model of interstitial cystitis/bladder pain syndrome (IC/BPS) in female rats. These results validate and extend the currently employed model by evaluating critical timepoints for obtaining treatment effects and identified that a second insult as an adult including repeat intravesical zymosan, intravesical lipopolysaccharide, acute footshock stress, neuropathic nociception (facial) or somatic inflammation (hindpaw) all resulted in magnified visceromotor responses to urinary bladder distension (UBD) in rats which had experienced NBI when compared with their controls. NBI also resulted in increased tone and reactivity of pelvic floor musculature to UBD, as well as increased responsiveness to intravesical potassium chloride solutions, abnormal anxiety measures (elevated plus maze) and an increased number of submucosal petechial hemorrhages following 30 min of hydrodistension of the bladder. These phenotypic findings have correlates to the clinical features of IC/BPS in humans and so support use of this model system to examine mechanisms of and treatments for IC/BPS.

Antagonistic and plant growth promotion effects of Mucor moelleri, a potential biocontrol agent

With the increasing demand for high quality and environmentally safe or green food, Biological Control Agents (BCAs) are playing critical roles in green agriculture, which in turn has paved the way for the requirement of effective, appropriate microbial antagonists. In this study, Mucor moelleri AA1 was isolated and investigated for its growth promotion and antagonism against Athelia rolfsii and Colletotrichum gloeosporiodes. The results showed a high antagonistic activity of M. moelleri against A. rolfsii and C. gloeosporiodes with percentage inhibitions of 73 % and 86 % respectively using the dual plate method, and the same antagonistic activity was also observed in liquid cocultures. A pot study analysis showed significant suppression of the diseases as well as growth promotion on tomato. Scanning electron microscopy (SEM) indicated that M. moelleri inhibited the growth of mycelium and the production of web-like materials. Based on headspace-solid phase microextraction (HS-SPME) analysis, microbial volatile compounds were determined, which were mainly aromatic compounds and alkaloids. Also, several antagonistic enzymes, such as β-1, 3- glucanase, proteases, catalase and ACC deaminase as well as the phytohormone IAA, were found to be produced by M. moelleri. Overall, these results combine to make M. moelleri a good prospective candidate for biological control and as a plant growth-promoting agent. The present study appears to be the first report identifying M. moelleri as a biological control agent.

Beta-Glucans from Fungi: Biological and Health-Promoting Potential in the COVID-19 Pandemic Era

Beta-glucans comprise a group of polysaccharides of natural origin found in bacteria, algae, and plants, e.g., cereal seeds, as well as microfungi and macrofungi (mushrooms), which are characterized by diverse structures and functions. They are known for their metabolic and immunomodulatory properties, including anticancer, antibacterial, and antiviral. Recent reports suggest a potential of beta-glucans in the prevention and treatment of COVID-19. In contrast to β-glucans from other sources, β-glucans from mushrooms are characterized by β-1,3-glucans with short β-1,6-side chains. This structure is recognized by receptors located on the surface of immune cells; thus, mushroom β-glucans have specific immunomodulatory properties and gained BRM (biological response modifier) status. Moreover, mushroom beta-glucans also owe their properties to the formation of triple helix conformation, which is one of the key factors influencing the bioactivity of mushroom beta-glucans. This review summarizes the latest findings on biological and health-promoting potential of mushroom beta-glucans for the treatment of civilization and viral diseases, with particular emphasis on COVID-19.

Macrophages from Rosa26-Integrated Cas9-Expressing C57BL/6J Mice Have a Putative TRIF-Mediated Defect in the TLR-3/4 Signaling

In this study, we report that the TLR4 ligand, LPS, and TLR3 ligand polyinosinic:polycytidylic acid failed to activate IRF3 or STAT1 in bone marrow-derived macrophages (BMMs) isolated from two independently generated lines of Rosa26-integrated Cas9-expressing C57BL/6J (B6) mice. RNA-sequencing analysis reveals that hundreds to thousands of genes including IFN-stimulated genes were differentially expressed in BMMs from these Cas9 strains compared with B6 upon LPS stimulation. Furthermore, the NF-κB signaling axis and TRIF-mediated necroptosis were also strongly reduced in response to LPS and polyinosinic:polycytidylic acid. In contrast, there were no defects in the responses of BMMs to ligands of the RIG-I, STING, TLR2, TLR9, and IFN receptors. Defects in TLR3 and TLR4 signaling were observed in mice with the B6 but not 129 background, and when Cas9 was integrated at the Rosa26 but not H11 locus. However, integration at the Rosa26 site, CAG promoter-driven Cas9 or eGFP were not individually sufficient to cause the defect. Taken together, the results of this study suggest a putative TRIF-mediated defect in TLR-3/4 signaling in BMMs from commercially available and widely used B6-Cas9-expressing mice.

Achyranthes bidentata Polysaccharide Activates Nuclear Factor-Kappa B and Promotes Cytokine Production in J774A.1 Cells Through TLR4/MyD88 Signaling Pathway

Achyranthes bidentata Blume, a traditional Chinese medicine, is widely acknowledged for its function of invigorating the liver and kidneys and as a stranguria-relieving diuretic and used in the treatment of edema, gonorrhea, and other diseases. Polysaccharide (ABPS), isolated from Achyranthes bidentata Blume, has been demonstrated to have multiple biological activities including immunomodulatory effects. However, the mechanisms underlying the effects of ABPS have not been fully investigated. The present study is conducted to explore the underlying mechanism of immunomodulatory activities of ABPS. Results showed that ABPS significantly increased the secretion of IL-1β and TNF-α in J744 A.1 cells. Nitric oxide (NO) also significantly increased after ABPS treatment. The special antibodies (Toll-like receptor 4 (TLR4) antibody and CD14/TLR4 antibody) significantly decreased the activation, while the Toll-like receptor 2 (TLR2) antibody could not abolish this activation. Meanwhile, pyrrolidine dithiocarbamate (PDTC), a specific inhibitor of NF-κB, remarkably inhibited the secretion of IL-1β and TNF-α induced by ABPS in J744 A.1 cells. Western blotting (WB) and confocal laser scanning microscopy (CLSM) showed that ABPS promoted NF-κB translocation into the nucleus. Furthermore, the mRNA and protein expression of TLR4 and MyD88 were significantly increased after ABPS treatment. Taken together, these findings suggested that the immunomodulatory mechanism of ABPS was associated with the secretion of cytokines by stimulating the NF-κB pathway through TLR4/MyD88 signaling.

Competing Bioaerosols May Influence the Seasonality of Influenza-Like Illnesses, including COVID-19. The Chicago Experience

Data from Chicago confirm the end of flu season coincides with the beginning of pollen season. More importantly, the end of flu season also coincides with onset of seasonal aerosolization of mold spores. Overall, the data suggest bioaerosols, especially mold spores, compete with viruses for a shared receptor, with the periodicity of influenza-like illnesses, including COVID-19, a consequence of seasonal factors that influence aerosolization of competing species.

NADPH Oxidase Limits Collaborative Pattern-Recognition Receptor Signaling to Regulate Neutrophil Cytokine Production in Response to Fungal Pathogen-Associated Molecular Patterns

Chronic granulomatous disease (CGD) is a primary immunodeficiency caused by genetic defects in leukocyte NADPH oxidase, which has both microbicidal and immunomodulatory roles. Hence, CGD is characterized by recurrent bacterial and fungal infections as well as aberrant inflammation. Fungal cell walls induce neutrophilic inflammation in CGD; yet, underlying mechanisms are incompletely understood. This study investigated the receptors and signaling pathways driving aberrant proinflammatory cytokine production in CGD neutrophils activated by fungal cell walls. Although cytokine responses to β-glucan particles were similar in NADPH oxidase-competent and NADPH oxidase-deficient mouse and human neutrophils, stimulation with zymosan, a more complex fungal particle, induced elevated cytokine production in NADPH oxidase-deficient neutrophils. The dectin-1 C-type lectin receptor, which recognizes β-glucans (1-3), and TLRs mediated cytokine responses by wild-type murine neutrophils. In the absence of NADPH oxidase, fungal pathogen-associated molecular patterns engaged additional collaborative signaling with Mac-1 and TLRs to markedly increase cytokine production. Mechanistically, this cytokine overproduction is mediated by enhanced proximal activation of tyrosine phosphatase SHP2-Syk and downstream Card9-dependent NF-κB and Card9-independent JNK-c-Jun. This activation and amplified cytokine production were significantly decreased by exogenous H₂O₂ treatment, enzymatic generation of exogenous H₂O₂, or Mac-1 blockade. Similar to zymosan, Aspergillus fumigatus conidia induced increased signaling in CGD mouse neutrophils for activation of proinflammatory cytokine production, which also used Mac-1 and was Card9 dependent. This study, to our knowledge, provides new insights into how NADPH oxidase deficiency deregulates neutrophil cytokine production in response to fungal cell walls.

Inhibitory affinity modulation of FcγRIIA ligand binding by glycosphingolipids by inside-out signaling

The interaction of the human FcγRIIA with immune complexes (ICs) promotes neutrophil activation and thus must be tightly controlled to avoid damage to healthy tissue. Here, we demonstrate that a fungal-derived soluble β-1,3/1,6-glucan binds to the glycosphingolipid long-chain lactosylceramide (LacCer) to reduce FcγRIIA-mediated recruitment to immobilized ICs under flow, a process requiring high-affinity FcγRIIA-immunoglobulin G (IgG) interactions. The inhibition requires Lyn phosphorylation of SHP-1 phosphatase and the FcγRIIA immunotyrosine-activating motif. β-glucan reduces the effective 2D affinity of FcγRIIA for IgG via Lyn and SHP-1 and, in vivo, inhibits FcγRIIA-mediated neutrophil recruitment to intravascular IgG deposited in the kidney glomeruli in a glycosphingolipid- and Lyn-dependent manner. In contrast, β-glucan did not affect FcγR functions that bypass FcγR affinity for IgG. In summary, we have identified a pathway for modulating the 2D affinity of FcγRIIA for ligand that relies on LacCer-Lyn-SHP-1-mediated inhibitory signaling triggered by β-glucan, a previously described activator of innate immunity.

Okubo et al. demonstrate that β-glucan binding to the glycosphingolipid lactosylceramide engages a Lyn kinase to SHP-1 phosphatase pathway that reduces FcγRIIA binding propensity for IgG, which suggests FcγRIIA affinity regulation by “inside-out” signaling. The β-glucan-lactosylceramide-Lyn axis prevents FcγRIIA-dependent neutrophil recruitment in vitro and to intravascular IgG deposits following glomerulonephritis.

β-glucan, "the knight of health sector": critical insights on physiochemical heterogeneities, action mechanisms and health implications

β-glucans, the class of biological response modifier has unceasing attention, not only for its immune stimulating but also for its role as prebiotics, modulator of physiological events etc. and is widely used in the treatment of cancer, diabetes, gastrointestinal disorders, cardiovascular diseases etc. However, β-glucan with different physiochemical properties is found to have discrete clinical functions and thus careful selection of the types of β-glucan plays pivotal role in providing significant and expected clinical outcome. Herein this review, we presented the factors responsible for diverse functional properties of β-glucan, their distinct mode of actions in regulating human health etc. Further, clinical aspects of different β-glucans toward the management of wound care, metabolic dysbiosis, fatty liver disorders and endurance training associated energy metabolism were compiled and exhibited in detail.

Distinct toll-like receptor signaling in the salamander response to tissue damage

BACKGROUND

Efficient wound healing or pathogen clearance both rely on balanced inflammatory responses. Inflammation is essential for effective innate immune-cell recruitment; however, excessive inflammation will result in local tissue destruction, pathogen egress, and ineffective pathogen clearance. Sterile and nonsterile inflammation operate with competing functional priorities but share common receptors and overlapping signal transduction pathways. In regenerative organisms such as the salamander, whole limbs can be replaced after amputation while exposed to a nonsterile environment. In mammals, exposure to sterile-injury Damage Associated Molecular Patterns (DAMPS) alters innate immune-cell responsiveness to secondary Pathogen Associated Molecular Pattern (PAMP) exposure.

RESULTS

Using new phospho-flow cytometry techniques to measure signaling in individual cell subsets we compared mouse to salamander inflammation. These studies demonstrated evolutionarily conserved responses to PAMP ligands through toll-like receptors (TLRs) but identified key differences in response to DAMP ligands. Co-exposure of macrophages to DAMPs/PAMPs suppressed MAPK signaling in mammals, but not salamanders, which activate sustained MAPK stimulation in the presence of endogenous DAMPS.

CONCLUSIONS

These results reveal an alternative signal transduction network compatible with regeneration that may ultimately lead to the promotion of enhanced tissue repair in mammals.

The Adjuvant Effects on Vaccine and the Immunomodulatory Mechanisms of Polysaccharides From Traditional Chinese Medicine

Vaccination is still the most successful strategy to prevent and control the spread of infectious diseases by generating an adequate protective immune response. However, vaccines composed of antigens alone can only stimulate weak immunogenicity to prevent infection in many cases. Adjuvant can enhance the immunogenicity of the antigens. Therefore, adjuvant is urgently needed to strengthen the immune response of the vaccines. An ideal adjuvant should be safe, cheap, biodegradable and biologically inert. In addition to having a long shelf life, it can also promote cellular and humoral immune responses. Traditional Chinese medicine (TCM) has many different ingredients, such as glycosides, polysaccharides, acids, terpenes, polyphenols, flavonoids, alkaloids, and so on. TCM polysaccharides are one of the main types of biologically active substances. They have a large range of pharmacological activities, especially immunomodulatory. TCM polysaccharides can regulate the immune system of animals by binding to multiple receptors on the surface of immune cells and activating different signal pathways. This review focuses on a comprehensive summary of the most recent developments in vaccine adjuvant effects of polysaccharides from many important TCM, such as Artemisia rupestris L., Cistanche deserticola, Pinus massoniana, Chuanminshen violaceum, Astragalus, Ganoderma lucidum, Codonopsis pilosula, Lycium barbarum, Angelica, Epimedium, and Achyranthes bidentata. Moreover, this review also introduces their immunomodulatory effects and the molecular mechanisms of action on animal bodies, which showed that TCM polysaccharides can activate macrophages, the signal pathway of T/B lymphocytes, regulate the signal pathway of natural killer cells, activate the complement system, and so on.

Review on Auricularia auricula-judae as a Functional Food: Growth, Chemical Composition, and Biological Activities

Although the application of Auricularia auricula-judae (AAJ) for health purposes has a long tradition in Asia, there is a lack of research on the functional nutrition of AAJ; the current research focused on polysaccharides has been too unitary compared to other mushrooms in recent years. Identification, extraction, and large-scale production of biologically active substances have emerged as critical determinants that determine AAJ becoming a functional food. AAJ is being treated in a restrained manner, despite having significant potential as a drug or a source of pure bioactive substances. Functional ingredients of mushrooms and AAJ have emerged as a new impetus for researchers interested in developing functional foods. This review presents an overview of current studies relevant to nutrition and the application of AAJ. The physiological conditions of AAJ and the corresponding functional ingredients beneficial to human health are reviewed to better understand the function and mechanisms of different nutrient contents. Relevant methods for evaluating the efficiency of extraction are also summarized. Finally, current limitations and the future scope for functional ingredients of AAJ are identified and discussed.

Fungal natural products galaxy: Biochemistry and molecular genetics toward blockbuster drugs discovery

Secondary metabolites synthesized by fungi have become a precious source of inspiration for the design of novel drugs. Indeed, fungi are prolific producers of fascinating, diverse, structurally complex, and low-molecular-mass natural products with high therapeutic leads, such as novel antimicrobial compounds, anticancer compounds, immunosuppressive agents, among others. Given that these microorganisms possess the extraordinary capacity to secrete diverse chemical scaffolds, they have been highly exploited by the giant pharma companies to generate small molecules. This has been made possible because the isolation of metabolites from fungal natural sources is feasible and surpasses the organic synthesis of compounds, which otherwise remains a significant bottleneck in the drug discovery process. Here in this comprehensive review, we have discussed recent studies on different fungi (pathogenic, non-pathogenic, commensal, and endophytic/symbiotic) from different habitats (terrestrial and marines), the specialized metabolites they biosynthesize, and the drugs derived from these specialized metabolites. Moreover, we have unveiled the logic behind the biosynthesis of vital chemical scaffolds, such as NRPS, PKS, PKS-NRPS hybrid, RiPPS, terpenoids, indole alkaloids, and their genetic mechanisms. Besides, we have provided a glimpse of the concept behind mycotoxins, virulence factor, and host immune response based on fungal infections.

Synthesis of the pentasaccharide repeating unit from Ruminococcus gnavus and measurement of its inflammatory properties

The roles played by the gut microbiome in human health are increasingly recognized, and the prevalence of specific microorganisms has been correlated with different diseases. For example, blooms of the Gram-positive bacterium Ruminococcus gnavus have been correlated with inflammatory bowel disease, and recently a polysaccharide produced by this organism was shown to stimulate release of inflammatory cytokines. This stimulation was proposed to signal through toll-like receptor 4 (TLR4). We have synthesized the pentasaccharide repeating unit of this polysaccharide and showed that it stimulates TNF-α and IL-6 release from bone marrow-derived dendritic cells (BMDCs) in a TLR4-dependent manner. A related glycan does not stimulate significant cytokine release, demonstrating TLR4 selectivity in glycan recognition.

The roles played by the gut microbiome in human health are increasingly recognized, and the prevalence of specific microorganisms has been correlated with different diseases.

Toll-like receptor-mediated innate immunity against herpesviridae infection: a current perspective on viral infection signaling pathways

Background

In the past decades, researchers have demonstrated the critical role of Toll-like receptors (TLRs) in the innate immune system. They recognize viral components and trigger immune signal cascades to subsequently promote the activation of the immune system.

Main body

Herpesviridae family members trigger TLRs to elicit cytokines in the process of infection to activate antiviral innate immune responses in host cells. This review aims to clarify the role of TLRs in the innate immunity defense against herpesviridae, and systematically describes the processes of TLR actions and herpesviridae recognition as well as the signal transduction pathways involved.

Conclusions

Future studies of the interactions between TLRs and herpesviridae infections, especially the subsequent signaling pathways, will not only contribute to the planning of effective antiviral therapies but also provide new molecular targets for the development of antiviral drugs.

Microbial interactions and immunity response in oral Candida species

Oral candidiasis are among the most common noncommunicable diseases, related with serious local and systemic illnesses. Although these infections can occur in all kinds of patients, they are more recurrent in immunosuppressed ones such as patients with HIV, hepatitis, cancer or under long antimicrobial treatments. Candida albicans continues to be the most frequently identified Candida spp. in these disorders, but other non-C. albicans Candida are rising. Understanding the immune responses involved in oral Candida spp. infections is a key feature to a successful treatment and to the design of novel therapies. In this review, we performed a literature search in PubMed and WoS, in order to examine and analyze common oral Candida spp.-bacteria/Candida-Candida interactions and the host immunity response in oral candidiasis.

Yeast cell wall polysaccharides enhanced expression of T helper type 1 and 2 cytokines profile in chicken B lymphocytes exposed to LPS challenge and enzyme treatment

1. The objective of this study was to investigate the potential immunomodulatory effects of yeast (Saccharomyces cerevisiae) and yeast-derived products treated with a cell wall lytic enzyme mixture on the gene expression of toll-like receptors and cytokines of chicken B cell line (DT 40) stimulated with lipopolysaccharide. 2. The effect of brewer's yeast (Y), yeast cell wall (YCW), distilled dried grains with solubles (DDGS) and a processed yeast + nucleotide-rich product (PY/N) treated with a yeast cell wall lytic enzyme (E) was assessed using a chicken B cells and LPS challenge model. 3. Relative gene expression of toll-like receptors (TLRs) and cytokines was investigated. Treatment of cells with Y, YCW, YCW + E and PY/N upregulated the expression of TLR2b following LPS challenge. Gene expression of TLR4 was downregulated in E, YCW and YCW + E treatments compared to control, while adding DDGS and PY/N upregulated the expression of TLR4 either before or after enzyme treatment. Following LPS challenge, expression of IL-4 and IL-10 was upregulated in cells treated with YCW and PY/N, both pre and post enzyme incubation. Adding YCW and PY/N to the cells challenged with LPS upregulated the expression of IFN-γ and IL-12 before and after enzyme treatment. Treatment of cells with YCW, DDGS and PY/N increased the expression of IL-6 prior to LPS challenge. 4. In conclusion, the results suggested that yeast-derived products affected immunomodulatory activities by changing the expression of cytokines involved in the innate immune response.

Therapeutic Effect of Corneal Crosslinking on Fungal Keratitis: Efficacy of Corneal Collagen Crosslinking as an Adjuvant Therapy for Fungal Keratitis in a Tertiary Eye Hospital in South India

PURPOSE

To evaluate the efficacy of CXL in treating fungal keratitis as an adjuvant therapy.

METHODS

Detailed clinical examination microbiological investigation was performed. Twenty fungal keratitis patients were recruited and randomized into two groups: group 1 (n= 11, standard antifungal), group 2 (n=9, corneal collagen crosslinking with standard antifungal). Corneal scraping and tear samples collected were subjected to real-time PCR targeting ITS, TLR analysis and cytokine analysis.

RESULTS

The mean time for complete resolution of ulcer for group 2 was significantly shorter compared to group 1 and the final mean BCVA was better for group 2. Expression of IL-1β, IL-8, IFN-γ significantly decreased immediately post CXL in group 2 patients. Significant downregulation of TLR 6, TLR-3, TLR-4 was observed 3-days post CXL compared to group 1 patients.

CONCLUSION

Adjuvant effect of CXL was significant in treating fungal keratitis compared to standalone antifungal treatment.

Toll-like receptors (TLRs) respond to tributyltin chloride (TBT-Cl) exposure in the river pufferfish (Takifugu obscurus): Evidences for its toxic injury function

Tributyltin chloride (TBT-Cl) residual in water body had become a noticeable ecological problem for aquatic ecosystems. Toll-like receptors (TLRs) are an ancient family of pattern recognition receptors that play key roles in detecting nonself antigens and immune system activation. In this study, we explored the effect of TBT-Cl exposure on four TLRs expression in river pufferfish, Takifugu obscurus. The four T. obscurus Toll-like receptors (To-TLRs) contained different types of domains such as leucine-rich repeats (LRRs), leucine-rich repeats, typical subfamily (LRR_TYP) and other special domains. The To-TLRs mRNA transcripts expressed in all tissues, also To-TLR2 was investigated with higher level in kidney, as well as To-TLR3 in kidney, while To-TLR18 in liver and To-TLR22 in intestine. After the acute and chronic exposure of TBT-Cl, To-TLR2 and To-TLR3 mRNA transcripts were significantly down-regulated in gill. However, To-TLR18 and To-TLR22 were significantly up-regulated in gill and liver. Moreover, the histology and immunohistochemistry (IHC) results showed the different injury degrees of TBT-Cl in liver and gill and implied the cytoplasm reorganization after TBT-Cl stress and the function of immunoregulation for To-TLRs to TBT-Cl exposure. All the results indicated that To-TLRs might involve in sensing and mediating innate immune responses caused by TBT-Cl for keeping detoxification homeostasis.

Mitochondrial DNA: A Key Regulator of Anti-Microbial Innate Immunity

During the last few years, mitochondrial DNA has attained much attention as a modulator of immune responses. Due to common evolutionary origin, mitochondrial DNA shares various characteristic features with DNA of bacteria, as it consists of a remarkable number of unmethylated DNA as 2′-deoxyribose cytidine-phosphate-guanosine (CpG) islands. Due to this particular feature, mitochondrial DNA seems to be recognized as a pathogen-associated molecular pattern by the innate immune system. Under the normal physiological situation, mitochondrial DNA is enclosed in the double membrane structure of mitochondria. However, upon pathological conditions, it is usually released into the cytoplasm. Growing evidence suggests that this cytosolic mitochondrial DNA induces various innate immune signaling pathways involving NLRP3, toll-like receptor 9, and stimulator of interferon genes (STING) signaling, which participate in triggering downstream cascade and stimulating to produce effector molecules. Mitochondrial DNA is responsible for inflammatory diseases after stress and cellular damage. In addition, it is also involved in the anti-viral and anti-bacterial innate immunity. Thus, instead of entire mitochondrial importance in cellular metabolism and energy production, mitochondrial DNA seems to be essential in triggering innate anti-microbial immunity. Here, we describe existing knowledge on the involvement of mitochondrial DNA in the anti-microbial immunity by modulating the various immune signaling pathways.

Inflammatory Bowel Disease: A Potential Result from the Collusion between Gut Microbiota and Mucosal Immune System

Host health depends on the intestinal homeostasis between the innate/adaptive immune system and the microbiome. Numerous studies suggest that gut microbiota are constantly monitored by the host mucosal immune system, and any slight disturbance in the microbial communities may contribute to intestinal immune disruption and increased susceptibility to inflammatory bowel disease (IBD), a chronic relapsing inflammatory condition of the gastrointestinal tract. Therefore, maintaining intestinal immune homeostasis between microbiota composition and the mucosal immune system is an effective approach to prevent and control IBD. The overall theme of this review is to summarize the research concerning the pathogenesis of IBD, with particular focus on the factors of gut microbiota-mucosal immune interactions in IBD. This is a comprehensive and in-depth report of the crosstalk between gut microbiota and the mucosal immune system in IBD pathogenesis, which may provide insight into the further evaluation of the therapeutic strategies for IBD.

GSP-2, a polysaccharide extracted from Ganoderma sinense, is a novel toll-like receptor 4 agonist

Ganoderma sinense is a Chinese unique medicinal fungus that has been used in folk medicine for thousands of years. Polysaccharides are considered to be biologically active ingredients due to their immune-modulating functions. Previously we found that GSP-2, a new polysaccharide isolated from Ganoderma sinense, exerts an immunomodulatory effect in human peripheral blood mononuclear cells but the underlying mechanism is unclear. The present study aimed to investigate how GSP-2 triggers immunologic responses and the implicated signaling pathways. GSP-2 effects were investigated both in a macrophagic cell line, RAW264.7, and in primary macrophages. Moreover, the molecular basis of GSP-2 recognition by immune cells, and the consequent activation of signaling cascades, were explored by employing recombinant human HEK293-TLR-Blue clones, individually overexpressing various Toll-like receptors. GSP-2 dose-dependently induced the overexpression of Toll-like receptor 4 (TLR4) but did not affect the expression of other TLRs. Moreover, GSP-2 induced TNFα secretion in primary macrophages from wild-type, but not TLR4-knockout mice. In addition, GSP-2 upregulated TLR4 protein expression and activated the MAPK pathway in RAW246.7 macrophages. Finally, GSP-2 induced the production of the cytokines TNFα, IL1β, and IL6. Our data demonstrated that GSP-2 was specifically recognized by TLR4, promoting cytokine secretion and immune modulation in macrophages.

Early Life Respiratory Syncytial Virus Infection and Asthmatic Responses

The infant's developing immune response is central to establishing a balanced system that reacts appropriately to infectious stimuli, but does not induce altered disease states with potential long-term sequelae. Respiratory syncytial virus may alter the immune system, affecting future responses. Early infection may have direct effects on the lung itself. Other early life processes contribute to the development of immune responses including assembly of the microbiome, which seems to have a particularly important role for establishing the immune environment. This review covers studies that have set up important paradigms and discusses recent data that direct research toward informative hypotheses.

Identification and characterization of an atypical RIG-I encoded by planarian Dugesia japonica and its essential role in the immune response

Retinoic acid-inducible gene I (RIG-I), an RNA sensor with a conserved structure, activates the host interferon (IFN) system to produce IFNs and cytokines for eliminating pathogens upon recognizing PAMPs. However, the biological functions and the mechanism by which RIG-I regulates the innate immunity response in invertebrates are still unknown at present. Here we identified an atypical RIG-I in planarian Dugesia japonica. Sequence analysis, 3D structure modeling and phylogenetic analysis showed that this atypical protein was clustered into a single clade at the base of the tree in invertebrates, suggesting that DjRIG-I is an ancient and unique protein of the RIG-I-like receptors (RLRs). In situ hybridization analysis revealed that the DjRIG-I mRNAs were predominantly expressed in the pharynx and head of the adult and regenerative planarians. Stimulation with PAMPs induced the over-expression of DjRIG-I in planarians. The molecular simulation demonstrated that DjRIG-I formed a large hole-structure for the docking of dsRNAs, and the pull-down assay confirmed the interaction between DjRIG-I and viral analog poly(I:C). Importantly, some representative antiviral/antibacterial genes in the RIG-I-mediated IFN and P38 signaling pathway, TBK1, IRF-3, Mx, and P38, were significantly upregulated in planarians stimulated with PAMPs. Interference of the DjRIG-I expression by RNAi, inhibited the PAMPs-induced over-expression, suggesting that DjRIG-I is a key player for downstream signaling events. These results indicate that DjRIG-I triggered the intracellular signaling cascades independent of the classical CARD domains and played an essential role in the virus/bacteria-induced innate immunity of planarian.

TLR10 and NFKBIA contributed to the risk of hip osteoarthritis: systematic evaluation based on Han Chinese population

Multiple lines of evidence have confirmed the importance of genetic factors for hip osteoarthritis (HOA). Our study aimed to investigate the associations of TLR10 and NFKBIA with respect to the HOA risk in Han Chinese individuals. A total of 1,043 HOA patients and 2,664 controls were recruited. Then, 23 tag single-nucleotide polymorphisms (SNPs) in the TLR10 and NFKBIA genes were selected for genotyping. Genetic association analyses were conducted in both single-marker and haplotype-based ways. Gene by gene, two-way interactions were analysed using a case-only method. Multiple bioinformatics tools were utilised to examine the potential functional significance of the SNPs. Two significant SNPs, rs11096957 (OR = 1.26, P = 1.35 × 10⁻⁵) and rs2273650 (OR = 1.2, P = 1.57 × 10⁻³), were significantly associated with HOA risk. Rs11096957 was also associated with the severity of the HOA. Bioinformatics analysis indicated that the allele T of rs2273650 would create new miRNA/SNP target duplexes, which suggests that rs2273650 could alter the NFKBIA expression by affecting the miRNA/SNP target duplexes. Our study identified significant association signals from NFKBIA with HOA for the first time, and it also confirmed the contribution of TLR10 to the HOA risk. These findings would provide clues for identifying individuals at high risk of HOA.

Selective constraint acting on TLR2 and TLR4 genes of Japanese Rana frogs

Toll-like receptors (TLRs) are an important component of innate immunity, the first line of pathogen defence. One of the major roles of TLRs includes recognition of pathogen-associated molecular patterns. Amphibians are currently facing population declines and even extinction due to chytridiomycosis caused by the Batrachochytrium dendrobatidis (Bd) fungus. Evidence from other vertebrates shows that TLR2 and TLR4 are involved in innate immunity against various fungi. Such genes therefore may play a functional role in amphibian-chytridiomycosis dynamics. Frogs from East Asia appear to be tolerant to Bd, so we examined the genetic diversity that underlies TLR2 and TLR4 from three Japanese Ranidae frog species, Rana japonica, R. ornativentris and R. tagoi tagoi (n = 5 per species). We isolated 27 TLR2 and 20 TLR4 alleles and found that these genes are evolutionarily conserved, with overall evidence supporting purifying selection. In contrast, site-by-site analysis of selection identified several specific codon sites under positive selection, some of which were located in the variable leucine rich repeat domains. In addition, preliminary expression levels of TLR2 and TLR4 from transcriptome data showed overall low expression. Although it remains unclear whether infectious pathogens are a selective force acting on TLRs of Japanese frogs, our results support that certain sites in TLRs of these species may have experienced pathogen-mediated selection.

Potential of Mushroom Compounds as Immunomodulators in Cancer Immunotherapy: A Review

Since time immemorial, plants and their compounds have been used in the treatment and management of various ailments. Currently, most of conventional drugs used for treatment of diseases are either directly or indirectly obtained from plant sources. The fungal group of plants is of significance, which not only provides food directly to man but also has been source of important drugs. For instance, commonly used antibiotics are derived from fungi. Fungi have also been utilized in the food industry, baking, and alcohol production. Apart from the economic importance of the microfungi, macrofungi have been utilized directly as food, which is usually got from their fruiting bodies, commonly known as mushrooms. Due to their richness in proteins, minerals, and other nutrients, mushrooms have also been associated with boosting the immune system. This makes mushrooms an important food source, especially for vegetarians and immunosuppressed individuals including the HIV/AIDS persons. In complementary and alternative medicines (CAMs), mushrooms are increasingly being accepted for treatment of various diseases. Mushrooms have been shown to have the ability to stimulate the immune system, modulate humoral and cellular immunity, and potentiate antimutagenic and antitumorigenic activity, as well as rejuvenating the immune system weakened by radiotherapy and chemotherapy in cancer treatment. This potential of mushrooms, therefore, qualifies them as candidates for immunomodulation and immunotherapy in cancer and other diseases' treatment. However, a critical review on mushroom's immune modulating potential in cancer has not been sufficiently addressed. This review puts forward insights into the immune activities of mushroom associated with anticancer activities.

Modulation of ovine SBD-1 expression by Saccharomyces cerevisiae in ovine ruminal epithelial cells

Background

The ovine rumen is involved in host defense responses and acts as the immune interface with the environment. The ruminal mucosal epithelium plays an important role in innate immunity and secretes antimicrobial innate immune molecules that have bactericidal activity against a variety of pathogens. Defensins are cationic peptides that are produced by the mucosal epithelia and have broad-spectrum antimicrobial activity. Sheep β-defensin-1 (SBD-1) is one of the most important antibacterial peptides in the rumen. The expression of SBD-1 is regulated by the probiotic, Saccharomyces cerevisiae (S.c); however, the regulatory mechanism has not yet been elucidated. In the current study, the effects of S.c on the expression and secretion of SBD-1 in ovine ruminal epithelial cells were investigated using quantitative real-time PCR (qPCR) and enzyme-linked immunosorbent assay (ELISA). In addition, specific inhibitors were used to block the nuclear factor kappa-light-chain enhancer of activated B cells (NF-κB), p38, JNK, and ERK1/2 signalling pathways separately or simultaneously, to determine the regulatory mechanism(s) governing S.c-induced SBD-1 upregulation.

Results

Incubation with S.c induced release of SBD-1 by ovine ruminal epithelial cells, with SBD-1 expression peaking after 12 h of incubation. The highest SBD-1 expression levels were achieved after treatment with 5.2 × 10⁷ CFU∙mL^− 1 S.c. Treatment with S.c resulted in significantly increased NF-κB, p38, JNK, ERK1/2, TLR2, and MyD88 mRNA expression. Whereas inhibition of mitogen-activated protein kinases (MAPKs) and NF-κB gene expression led to a decrease in SBD-1 expression.

Conclusions

S.c was induced SBD-1 expression and the S.c-induced up-regulation of SBD-1 expression may be related to TLR2 and MyD88 in ovine ruminal epithelial cells. This is likely simultaneously regulated by the MAPKs and NF-κB pathways with the p38 axis of the MAPKs pathway acting as the primary regulator. Thus, the pathways regulating S.c-induced SBD-1 expression may be related to TLR2-MyD88-NF-κB/MAPKs, with the TLR2-MyD88-p38 component of the TLR2-MyD88-MAPKs signalling acting as the main pathway.

Atomic Force Microscopy: A Promising Tool for Deciphering the Pathogenic Mechanisms of Fungi in Cystic Fibrosis

During the past decades, atomic force microscopy (AFM) has emerged as a powerful tool in microbiology. Although most of the works concerned bacteria, AFM also permitted major breakthroughs in the understanding of physiology and pathogenic mechanisms of some fungal species associated with cystic fibrosis. Complementary to electron microscopies, AFM offers unprecedented insights to visualize the cell wall architecture and components through three-dimensional imaging with nanometer resolution and to follow their dynamic changes during cell growth and division or following the exposure to drugs and chemicals. Besides imaging, force spectroscopy with piconewton sensitivity provides a direct means to decipher the forces governing cell-cell and cell-substrate interactions, but also to quantify specific and non-specific interactions between cell surface components at the single-molecule level. This nanotool explores new ways for a better understanding of the structures and functions of the cell surface components and therefore may be useful to elucidate the role of these components in the host-pathogen interactions as well as in the complex interplay between bacteria and fungi in the lung microbiome.

Effect of the Addition of Saccharomyces Cerevisiae Yeast Cell Walls to Diets with Mycotoxins on the Performance and Immune Responses of Broilers

This study was conducted to evaluate the effect of Saccharomyces cerevisiae yeast cell walls (YCWs) in diets with low doses of aflatoxin B1 (AFB1) and ochratoxin A (OTA), alone or in combination, on broiler performance and immune response. A total of 210 male broilers aged 1-21 days were used. Broilers were completely randomized into seven treatments with five replicates of six broilers each, as follows: 1) control diet; 2) control + 350 µg/kg AFB1; 3) Control + 350 µg/kg OTA; 4) Control + 350 µg/kg AFB1 and 350 µg/kg OTA; 5) Control + 350 µg/kg AFB1 and 1.5 kg/ton YCW; 6) control + 350 µg/kg OTA and 1.5 kg/ton YCW; 7) control + 350 µg/kg AFB1, 350 µg/kg OTA, and 1.5 kg/ton YCW. The broilers were housed under environmentally controlled conditions in Petersime battery cages. Weight gain, feed intake, and feed conversion index were measured. The relative weights of the thymus, spleen, and bursa of Fabricius (BF) were evaluated. The local immune response was assessed by quantifying the level of intestinal immunoglobulin A (IgA). The cellular immune response was evaluated using a delayed hypersensitivity test. Hemograms and blood cell counts were also performed. The results showed that mycotoxins decreased performance and reduced the immune response (p<0.05) of broilers. Weight gain and feed conversion improved in the groups receiving YCWs. The YCWs increased (p<0.05) intestinal IgAs and the cellular immune response (p<0.05). The addition of YCWs also affected the relative weight of the thymus, spleen, and BF (p<0.05), and the leukocyte, lymphocyte, and heterophil counts (p<0.05). The addition of YCWs can be an alternative to counterage the negative effect of low doses of AFB1 and OTA in broilers diets.

Cell type-specific regulatory effects of glucocorticoids on cutaneous TLR2 expression and signalling

Glucocorticoids (GCs) induce Toll-like receptor (TLR) 2 expression and synergistically upregulate TLR2 with pro-inflammatory cytokines or bacteria. These paradoxical effects have drawn attention to the inflammatory initiating or promoting effects of GCs, as GC treatment can provoke inflammatory skin diseases. Here, we aimed to investigate the regulatory effects of GCs in human skin cells of different epidermal and dermal layers. We found that Dex induced TLR2 expression mainly in undifferentiated and less in calcium-induced differentiated keratinocytes but not in HaCaT cells or fibroblasts, however, Dex reduced TLR1/6 expression. Stimulation with Dex under inflammatory conditions further increased TLR2 but not TLR1 or TLR6 levels in keratinocytes. Increased ligand-induced interaction of TLR2 with MyD88 and expression of the adaptor protein TRAF6 indicated enhanced TLR2 signalling, whereas TLR2/1 or TLR2/6 signalling was not increased in Dex-pretreated keratinocytes. GC-increased TLR2 expression was negatively regulated by JNK MAPK signalling when stimulated with Propionibacterium acnes. Our results provide novel insights into the molecular mechanisms of glucocorticoid-mediated expression and function of TLR2 in human skin cells and the understanding of the mechanisms of corticosteroid side effects.

Multiple roles of filopodial dynamics in particle capture and phagocytosis and phenotypes of Cdc42 and Myo10 deletion

Macrophage filopodia, finger-like membrane protrusions, were first implicated in phagocytosis more than 100 years ago, but little is still known about the involvement of these actin-dependent structures in particle clearance. Using spinning disk confocal microscopy to image filopodial dynamics in mouse resident Lifeact-EGFP macrophages, we show that filopodia, or filopodia-like structures, support pathogen clearance by multiple means. Filopodia supported the phagocytic uptake of bacterial (Escherichia coli) particles by (i) capturing along the filopodial shaft and surfing toward the cell body, the most common mode of capture; (ii) capturing via the tip followed by retraction; (iii) combinations of surfing and retraction; or (iv) sweeping actions. In addition, filopodia supported the uptake of zymosan (Saccharomyces cerevisiae) particles by (i) providing fixation, (ii) capturing at the tip and filopodia-guided actin anterograde flow with phagocytic cup formation, and (iii) the rapid growth of new protrusions. To explore the role of filopodia-inducing Cdc42, we generated myeloid-restricted Cdc42 knock-out mice. Cdc42-deficient macrophages exhibited rapid phagocytic cup kinetics, but reduced particle clearance, which could be explained by the marked rounded-up morphology of these cells. Macrophages lacking Myo10, thought to act downstream of Cdc42, had normal morphology, motility, and phagocytic cup formation, but displayed markedly reduced filopodia formation. In conclusion, live-cell imaging revealed multiple mechanisms involving macrophage filopodia in particle capture and engulfment. Cdc42 is not critical for filopodia or phagocytic cup formation, but plays a key role in driving macrophage lamellipodial spreading.