Immune modulation by complement receptor 3-dependent human monocyte TGF-β1-transporting vesicles

Complement receptor 3-dependent engagement by Candida glabrata β-glucan modulates dendritic cells to induce regulatory T-cell expansion

Candida glabrata is an important pathogen causing invasive infection associated with a high mortality rate. One mechanism that causes the failure of Candida eradication is an increase in regulatory T cells (Treg), which play a major role in immune suppression and promoting Candida pathogenicity. To date, how C. glabrata induces a Treg response remains unclear. Dendritic cells (DCs) recognition of fungi provides the fundamental signal determining the fate of the T-cell response. This study investigated the interplay between C. glabrata and DCs and its effect on Treg induction. We found that C. glabrata β-glucan was a major component that interacted with DCs and consequently mediated the Treg response. Blocking the binding of C. glabrata β-glucan to dectin-1 and complement receptor 3 (CR3) showed that CR3 activation in DCs was crucial for the induction of Treg. Furthermore, a ligand-receptor binding assay showed the preferential binding of C. glabrata β-glucan to CR3. Our data suggest that C. glabrata β-glucan potentially mediates the Treg response, probably through CR3-dependent activation in DCs. This study contributes new insights into immune modulation by C. glabrata that may lead to a better design of novel immunotherapeutic strategies for invasive C. glabrata infection.

The incorporation of acetylated LAP-TGF-β1 proteins into exosomes promotes TNBC cell dissemination in lung micro-metastasis

Triple-negative breast cancer (TNBC) stands as the breast cancer subtype with the highest recurrence and mortality rates, with the lungs being the common site of metastasis. The pulmonary microenvironment plays a pivotal role in the colonization of disseminated tumor cells. Herein, this study highlights the crucial role of exosomal LAP-TGF-β1, the principal form of exosomal TGF-β1, in reshaping the pulmonary vascular niche, thereby facilitating TNBC lung metastasis. Although various strategies have been developed to block TGF-β signaling and have advanced clinically, their significant side effects have limited their therapeutic application. This study demonstrates that in lung metastatic sites, LAP-TGF-β1 within exosomes can remarkably reconfigure the pulmonary vascular niche at lower doses, bolstering the extravasation and colonization of TNBC cells in the lungs. Mechanistically, under the aegis of the acetyltransferase TIP60, a non-canonical KFERQ-like sequence in LAP-TGF-β1 undergoes acetylation at the K304 site, promoting its interaction with HSP90A and subsequent transport into exosomes. Concurrent inhibition of both HSP90A and TIP60 significantly diminishes the exosomal burden of LAP-TGF-β1, presenting a promising therapeutic avenue for TNBC lung metastasis. This study not only offers fresh insights into the molecular underpinnings of TNBC lung metastasis but also lays a foundation for innovative therapeutic strategies.

The Promise of Complement Therapeutics in Solid Organ Transplantation

Transplantation is the ideal therapy for end-stage organ failure, but outcomes for all transplant organs are suboptimal, underscoring the need to develop novel approaches to improve graft survival and function. The complement system, traditionally considered a component of innate immunity, is now known to broadly control inflammation and crucially contribute to induction and function of adaptive T-cell and B-cell immune responses, including those induced by alloantigens. Interest of pharmaceutical industries in complement therapeutics for nontransplant indications and the understanding that the complement system contributes to solid organ transplantation injury through multiple mechanisms raise the possibility that targeting specific complement components could improve transplant outcomes and patient health. Here, we provide an overview of complement biology and review the roles and mechanisms through which the complement system is pathogenically linked to solid organ transplant injury. We then discuss how this knowledge has been translated into novel therapeutic strategies to improve organ transplant outcomes and identify areas for future investigation. Although the clinical application of complement-targeted therapies in transplantation remains in its infancy, the increasing availability of new agents in this arena provides a rich environment for potentially transformative translational transplant research.

Understanding yeast shells: structure, properties and applications

Background and purpose

The employment of yeasts for biomedical purposes has become increasingly frequent for the delivery of prophylactic and therapeutic products. Its structural components, such as β-glucans, mannan, and chitin, can be explored as immunostimulators that show safety and low toxicity. Besides, this system minimizes antigen degradation after administration, facilitating the delivery to the target cells.

Review approach

This review sought to present molecules derived from yeast, called yeast shells (YS), and their applications as carrier vehicles for drugs, proteins, and nucleic acids for immunotherapy purposes. Furthermore, due to the diversity of information regarding the production and immunostimulation of these compounds, a survey of the protocols and immune response profiles generated was presented.

Key results

The use of YS has allowed the development of strategies that combine efficiency and effectiveness in antigen delivery. The capsular structure can be recognized and phagocytized by dendritic cells and macrophages. In addition, the combination with different molecules, such as nanoparticles or even additional adjuvants, improves the cargo loading, enhancing the system. Activation by specific immune pathways can also be achieved by different administration routes.

Conclusion

Yeast derivatives combined in different ways can increase immunostimulation, enhancing the delivery of medicines and vaccine antigens. These aspects, combined with the simplicity of the production steps, make these strategies more accessible to be applied in the prevention and treatment of various diseases.

Exploring therapeutic avenues: mesenchymal stem/stromal cells and exosomes in confronting enigmatic biofilm-producing fungi

Fungal infections concomitant with biofilms can demonstrate an elevated capacity to withstand substantially higher concentrations of antifungal agents, contrasted with infectious diseases caused by planktonic cells. This inherent resilience intrinsic to biofilm-associated infections engenders a formidable impediment to effective therapeutic interventions. The different mechanisms that are associated with the intrinsic resistance of Candida species encompass drug sequestration by the matrix, drug efflux pumps, stress response cell density, and the presence of persister cells. These persisters, a subset of fungi capable of surviving hostile conditions, pose a remarkable challenge in clinical settings in virtue of their resistance to conventional antifungal therapies. Hence, an exigent imperative has arisen for the development of novel antifungal therapeutics with specific targeting capabilities focused on these pathogenic persisters. On a global scale, fungal persistence and their resistance within biofilms generate an urgent clinical need for investigating recently introduced therapeutic strategies. This review delves into the unique characteristics of Mesenchymal stem/stromal cells (MSCs) and their secreted exosomes, which notably exhibit immunomodulatory and regenerative properties. By comprehensively assessing the current literature and ongoing research in this field, this review sheds light on the plausible mechanisms by which MSCs and their exosomes can be harnessed to selectively target fungal persisters. Additionally, prospective approaches in the use of cell-based therapeutic modalities are examined, emphasizing the importance of further research to overcome the enigmatic fungal persistence.

Stress Conditions Affect the Immunomodulatory Potential of Candida albicans Extracellular Vesicles and Their Impact on Cytokine Release by THP-1 Human Macrophages

Human immune cells possess the ability to react complexly and effectively after contact with microbial virulence factors, including those transported in cell-derived structures of nanometer sizes termed extracellular vesicles (EVs). EVs are produced by organisms of all kingdoms, including fungi pathogenic to humans. In this work, the immunomodulatory properties of EVs produced under oxidative stress conditions or at host concentrations of CO2 by the fungal pathogen Candida albicans were investigated. The interaction of EVs with human pro-monocytes of the U-937 cell line was established, and the most notable effect was attributed to oxidative stress-related EVs. The immunomodulatory potential of tested EVs against human THP-1 macrophages was verified using cytotoxicity assay, ROS-production assay, and the measurement of cytokine production. All fungal EVs tested did not show a significant cytotoxic effect on THP-1 cells, although a slight pro-oxidative impact was indicated for EVs released by C. albicans cells grown under oxidative stress. Furthermore, for all tested types of EVs, the pro-inflammatory properties related to increased IL-8 and TNF-α production and decreased IL-10 secretion were demonstrated, with the most significant effect observed for EVs released under oxidative stress conditions.

Extracellular vesicles in bacterial and fungal diseases - Pathogenesis to diagnostic biomarkers

Intercellular communication among microbes plays an important role in disease exacerbation. Recent advances have described small vesicles, termed as "extracellular vesicles" (EVs), previously disregarded as "cellular dust" to be vital in the intracellular and intercellular communication in host-microbe interactions. These signals have been known to initiate host damage and transfer of a variety of cargo including proteins, lipid particles, DNA, mRNA, and miRNAs. Microbial EVs, referred to generally as "membrane vesicles" (MVs), play a key role in disease exacerbation suggesting their importance in pathogenicity. Host EVs help coordinate antimicrobial responses and prime the immune cells for pathogen attack. Hence EVs with their central role in microbe-host communication, may serve as important diagnostic biomarkers of microbial pathogenesis. In this review, we summarize current research regarding the roles of EVs as markers of microbial pathogenesis with specific focus on their interaction with host immune defence and their potential as diagnostic biomarkers in disease conditions.

Convergent and divergent roles of the glucose-responsive kinase SNF4 in Candida tropicalis

The sucrose non-fermenting 1 (SNF1) complex is a heterotrimeric protein kinase complex that is an ortholog of the mammalian AMPK complex and is evolutionally conserved in most eukaryotes. This complex contains a catalytic subunit (Snf1), a regulatory subunit (Snf4) and a scaffolding subunit (Sip1/Sip2/Gal73) in budding yeast. Although the function of AMPK has been well studied in Saccharomyces cerevisiae and Candida albicans, the role of AMPK in Candida tropicalis has never been investigated. In this study, we focused on SNF4 in C. tropicalis as this fungus cannot produce a snf1Δ mutant. We demonstrated that C. tropicalis SNF4 shares similar roles in glucose derepression and is necessary for cell wall integrity and virulence. The expression of both SNF1 and SNF4 was significantly induced when glucose was limited. Furthermore, snf4Δ strains exhibited high sensitivity to many surface-perturbing agents because the strains contained lower levels of glucan, chitin and mannan. Interestingly, in contrast to C. albicans sak1Δ and snf4Δ, C. tropicalis snf4Δ exhibited phenotypes for cell aggregation and pseudohypha production. These data indicate that SNF4 performs convergent and divergent roles in C. tropicalis and possibly other unknown roles in the C. tropicalis SNF1-SNF4 AMPK pathway.

Phylactic role of anti-lipoarabinomannan IgM directed against mannan core during mycobacterial infection in macrophages

Mycobacteria enter host phagocytes, such as macrophages by binding to several receptors on phagocytes. Several mycobacterial species, including Mycobacterium tuberculosis have evolved systems to evade host bactericidal pathways. Lipoarabinomannan (LAM) is an essential mycobacterial molecule for both binding to phagocytes and escaping from bactericidal pathways. Integrin CD11b plays critical roles as a phagocytic receptor and contributes to host defense by mediating both nonopsonic and opsonic phagocytosis. However, the mechanisms by which CD11b-mediated phagocytosis associates with LAM and drives the phagocytic process of mycobacteria remain to be fully elucidated. We recently identified TMDU3 as anti-LAM IgM antibody against the mannan core of LAM. The present study investigated the roles of CD11b and TMDU3 in macrophage phagocytosis of mycobacteria and subsequent bactericidal lysosomal fusion to phagosomes. CD11b knockout cells generated by a CRISPR/Cas9 system showed significant attenuation of the ability to phagocytose non-opsonized mycobacteria and LAM-conjugated beads. Moreover, recombinant human CD11b protein was found to bind to LAM. TMDU3 markedly inhibited macrophage phagocytosis of non-opsonized mycobacteria. This antibody slightly increased the phagocytosis of mycobacteria under opsonized conditions, whereas it significantly enhanced CD11b-mediated bactericidal functions. Taken together, these results show a novel phylactic role of anti-LAM IgM during mycobacterial infection in macrophages.

Sequence Variation of Candida albicans Sap2 Enhances Fungal Pathogenicity via Complement Evasion and Macrophage M2-Like Phenotype Induction

Candida albicans (C. albicans) is an opportunistic pathogen increasingly causing candidiasis worldwide. This study aims to investigate the pattern of systemic immune responses triggered by C. albicans with disease associated variation of Sap2, identifying the novel evasion strategies utilized by clinical isolates. Specifically, a variation in clinical isolates is identified at nucleotide position 817 (G to T). This homozygous variation causes the 273rd amino acid exchange from valine to leucine, close to the proteolytic activation center of Sap2. The mutant (Sap2-273L) generated from SC5314 (Sap2-273V) background carrying the V273L variation within Sap2 displays higher pathogenicity. In comparison to mice infected with Sap2-273V strain, mice infected with Sap2-273L exhibit less complement activation indicated by less serum C3a generation and weaker C3b deposition in the kidney. This inhibitory effect is mainly achieved by Sap2_273L -mediated stronger degradation of C3 and C3b. Furthermore, mice infected with Sap2-273L strain exhibit more macrophage phenotype switching from M0 to M2-like and more TGF-β release which further influences T cell responses, generating an immunosuppressed cellular microenvironment characterized by more Tregs and exhausted T cell formation. In summary, the disease-associated sequence variation of Sap2 enhances pathogenicity by complement evasion and M2-like phenotype switching, promoting a more efficient immunosuppressed microenvironment.

Astrocyte-derived exosomal lncRNA 4933431K23Rik modulates microglial phenotype and improves post-traumatic recovery via SMAD7 regulation

Astrocyte-microglial interaction plays a crucial role in brain injury-associated neuroinflammation. Our previous data illustrated that astrocytes secrete microRNA, leading to anti-inflammatory effects on microglia. Long non-coding RNAs participate in neuroinflammation regulation after traumatic brain injury. However, the effect of astrocytes on microglial phenotype via long non-coding RNAs and the underlying molecular mechanisms remain elusive. We used long non-coding RNA sequencing on murine astrocytes and found that exosomal long non-coding RNA 4933431K23Rik attenuated traumatic brain injury-induced microglial activation in vitro and in vivo and ameliorated cognitive function deficiency. Furthermore, microRNA and messenger RNA sequencing together with binding prediction illustrated that exosomal long non-coding RNA 4933431K23Rik up-regulates E2F7 and TFAP2C expression by sponging miR-10a-5p. Additionally, E2F7 and TFAP2C, as transcription factors, regulated microglial Smad7 expression. Using Cx3cr1-Smad7 overexpression of adeno-associated virus, microglia specifically overexpressed Smad7 in the attenuation of neuroinflammation, resulting in less cognitive deficiency after traumatic brain injury. Mechanically, overexpressed Smad7 physically binds to IκBα and inhibits its ubiquitination, preventing NF-κB signaling activation. The Smad7 activator asiaticoside alleviates neuroinflammation and protects neuronal function in traumatic brain injury mice. This study revealed that an exosomal long non-coding RNA from astrocytes attenuates microglial activation after traumatic brain injury by up-regulating Smad7, providing a potential therapeutic target.

Doublecortin-like kinase 1 activates NF-κB to induce inflammatory responses by binding directly to IKKβ

Doublecortin-like kinase 1 (DCLK1), a microtubule-associated protein kinase, is involved in neurogenesis, and its levels are elevated in various human cancers. Recent studies suggest that DCLK1 may relate to inflammatory responses in the mouse model of colitis. However, cellular pathways engaged by DCLK1, and potential substrates of the kinase remain undefined. To understand how DCLK1 regulates inflammatory responses, we utilized the well-established lipopolysaccharide (LPS)-stimulated macrophages and mouse model. Through a range of macrophage-based and cell-free platforms, we discovered that DCLK1 binds directly with the inhibitor of κB kinase β (IKKβ) and induces IKKβ phosphorylation on Ser177/181 to initiate nuclear factor-κB (NF-κB) pathway. Deficiency in DCLK1, achieved by silencing or through pharmacological inhibition, prevented LPS-induced NF-κB activation and cytokine production in macrophages. We further show that mice with myeloid-specific DCLK1 knockout or DCLK1 inhibitor treatment are protected against LPS-induced acute lung injury and septic death. Our studies report a novel functional role of macrophage DCLK1 as a direct IKKβ regulator in inflammatory signaling and suggest targeted therapy against DCLK1 for inflammatory diseases.

The impact of hypoxia on extracellular vesicle secretome profile of cancer

Extracellular vesicles (EVs) are emerging as key mediators of cell-to-cell communications and signal transporters between tumor and stroma, and hypoxia is a critical characteristic of tumor microenvironment (TME) in solid cancers. Hypoxia stimulates tumor cells to generate and secrete more EVs, and the EVs shed from cancer transfer biological information to boost hypoxia and hypoxia inducible factor (HIF) functionality. Hypoxia alters EV secretome profile to carry pro-tumorigenic factors for promoting numerous tumor-related processes including increased cancer cell proliferation and survival, immune escape, aberrant angiogenesis, and invasion and metastasis. Exosomal hypoxia inducible factor (HIF)-1α is an essential driver of epithelial-mesenchymal transition (EMT) and stemness profile in cancer. Hypoxic cancer-derived EVs are also contributed to therapy resistance. In fact, EVs are messengers of hypoxic tolerance in cancer, which enable adaptation of tumor cells to changes occurring within TME for their further resistance and metastasis. Tracing EVs shed from hypoxic tumor cells into plasma provide important information about the genomic signature of cancer. In this review, we aimed to discuss about key tumorigenic events promoted by inter-connections between hypoxia and EVs, mainly exosomes, secreted into tumor area focusing on key hallmarks of cancer.

Protective role of Nrf2 in zinc oxide nanoparticles-induced lung inflammation in female mice and sexual dimorphism in susceptibility

BACKGROUND

Zinc oxide nanoparticles (ZnO-NPs) are currently employed in various products such as rubber, paint, and cosmetics. Our group reported recently that Nrf2 protein provides protection against pulmonary inflammation induced by ZnO-NPs in male mice. The current study investigated the effect of Nrf2 deletion on the lung inflammatory response in female mice exposed to ZnO-NPs.

METHODS

An equal number of female Nrf2^-/- mice and female Nrf2^+/+ mice (24 each) were allocated into three equal groups, and each was exposed to ZnO-NPs at either 0, 10 or 30 µg ZnO-NPs/mouse through pharyngeal aspiration. Bronchoalveolar lavage fluid (BALF) and lungs were examined 14 days later to determine the number of inflammatory cells, the protein level, and for scoring inflammation histopathologically. The mRNA levels of Nrf2-dependent antioxidant enzymes and proinflammatory cytokine in lung tissue were also measured.

RESULTS

Exposure to ZnO-NPs increased all types of BALF cells and lung inflammation scores in both of female Nrf2-null (Nrf2^-/-) and wild-type (Nrf2^+/+) mice, and Nrf2 deletion enhanced ZnO-NPs-induced increase in the number of eosinophils in BALF. Exposure to ZnO-NPs dose-dependently increased the level of oxidized glutathione (GSSG), and mRNA levels of proinflammatory cytokines/chemokines; KC, MIP-2, IL-6, IL-1β and MCP-1 only in wild-type mice. Nrf2 deletion decreased total glutathione levels and basal mRNA levels of SOD1 and NQO1, and increased the basal mRNA level of above proinflammatory cytokines/chemokines. Nrf2 deletion enhanced ZnO-NPs-induced downregulation of GcLc, GR and TGF-β and upregulation of HO-1 and TNF-α. Taken together with our previous results in male mice, our results showed a lower susceptibility of females to lung tissue inflammation, relative to males, irrespective of Nrf2 deletion, and that enhancement of ZnO-NPs-induced upregulation of HO-1 and TNF-α and downregulation of GcLc, GR and TGF-β by deletion of Nrf2 is specific to female mice.

CONCLUSION

We conclude that Nrf2 provides protection in female mice against increase in BALF eosinophils, probably through down-regulation of proinflammatory cytokines/chemokines and upregulation of oxidative stress-related genes. The study also suggests lower susceptibility to lung tissue inflammation in female mice relative to their male counterparts and the synergistic effects of Nrf2 and exposure to ZnO-NPs on mRNA expression of GcLc, GR, HO-1, TGF-β or TNF-α in female mice.

Antimicrobial Effect of Extracellular Vesicles Derived From Human Oral Mucosal Epithelial Cells on Candida albicans

Candida albicans (C. albicans) is a commensal microorganism that colonizes the mucosal surfaces of healthy individuals. Changes in the host or environment can lead to overgrowth of C. albicans and infection of the host. Extracellular vesicles (EVs) are released by almost all cell types and play an increasingly recognized role in fighting microbial infection. The aim of the present study was to assess whether EVs derived from human oral mucosal epithelial (Leuk-1) cells can suppress the growth and invasion of C. albicans. The in vitro efficacy of Leuk-1-EVs against C. albicans was assessed by optical microscopy, laser scanning confocal microscopy, scanning electron microscopy, and transmission electron microscopy. The germ tube formation rate, the percentage of hyphae and the microcolony optical density were also used to analyze the growth of C. albicans in a coculture model with Leuk-1 cells and EVs or after inhibition of the secretion of EVs. A mouse model of oral candidiasis was established and submucosal injection of Leuk-1-EVs in the tongue was performed. Macroscopic observation, H&E staining, PAS staining, and scanning electron microscopy were used to assess antifungal effects of Leuk-1-EVs in vivo. The in vitro results showed that the growth of C. albicans was inhibited and that the morphology and ultrastructure were changed following Leuk-1-EVs treatment. The in vivo results exhibited that white lesions of the tongue, C. albicans infection, and oral mucosal inflammation of the infected mice were significantly alleviated after Leuk-1-EVs treatment. We thus reveal an antifungal capability of EVs derived from oral epithelial cells against C. albicans that is mediated by direct damage effects and potential synergy between EVs and human oral mucosal epithelial cells. This finding offers an intriguing, previously overlooked method of antifungal defense against C. albicans.

Immune Cell-Derived Extracellular Vesicles in the Face of Pathogenic Infections

Extracellular Vesicles (EVs) are a collection of vesicles released from cells that play an important role in intercellular communication. Microbial infections are known as one of the major problems in the medical field. Considering the increasing resistance of strains to routine drug treatments, the need for new therapies seems to be more than ever. Recent studies have shown that the EVs released from immune cells during microbial infections had anti-microbial effects or were able to induce neighbouring cells to display anti-microbial effects. This mini-review aimed to explore the latest studies on immune cell-derived EVs in viral, bacterial, fungal, and parasitic infections. Review of the literature demonstrated that specific cargos in EVs were involved in the fight against pathogenic infections. Additionally, the transport of appropriate bioactive molecules including miRNAs, mRNAs, and proteins via EVs could mediate the anti-microbial process. Thus, it could be a proof-of-principle that therapeutic approaches based on EVs derived from immune cells could offer a promising path forward, which is still in early stages and needs further assessments.

RNA-based therapeutics to treat human fungal infections

In recent decades, RNA-based therapeutics have transitioned from a near impossibility to a compelling treatment alternative for genetic disorders and infectious diseases. The mRNA vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are truly groundbreaking, and new adaptations are already being proposed to fight other microbes. Unfortunately, the potential of RNA-based therapeutics to treat human fungal infections has remained mostly absent from the conversation, despite the fact that invasive fungal infections kill as many per year as tuberculosis and even more than malaria. Here, we argue that RNA-based therapeutics should be investigated for the treatment of human fungal infections and discuss several major roadblocks and potential circumventions that may allow for the realization of RNA-based therapies against human fungal pathogens.

Role of Complement System in Kidney Transplantation: Stepping From Animal Models to Clinical Application

Kidney transplantation is a life-saving strategy for patients with end-stage renal diseases. Despite the advances in surgical techniques and immunosuppressive agents, the long-term graft survival remains a challenge. Growing evidence has shown that the complement system, part of the innate immune response, is involved in kidney transplantation. Novel insights highlighted the role of the locally produced and intracellular complement components in the development of inflammation and the alloreactive response in the kidney allograft. In the current review, we provide the updated understanding of the complement system in kidney transplantation. We will discuss the involvement of the different complement components in kidney ischemia-reperfusion injury, delayed graft function, allograft rejection, and chronic allograft injury. We will also introduce the existing and upcoming attempts to improve allograft outcomes in animal models and in the clinical setting by targeting the complement system.

Secretome Profiling of Atlantic Salmon Head Kidney Leukocytes Highlights the Role of Phagocytes in the Immune Response to Soluble β-Glucan

β‐Glucans (BG) are glucose polymers which are produced in bacteria and fungi but not in vertebrate organisms. Being recognized by phagocytic leukocytes including macrophages and neutrophils through receptors such as dectin-1 and Complement receptor 3 (CR3), the BG are perceived by the innate immune system of vertebrates as foreign substances known as Pathogen Associated Molecular Patterns (PAMPs). The yeast-derived BG has been recognized for its potent biological activity and it is used as an immunomodulator in human and veterinary medicine. The goal of the current study was to characterize the immunostimulatory activity of soluble yeast BG in primary cultures of Atlantic salmon (Salmo salar) head kidney leukocytes (HKLs) in which phagocytic cell types including neutrophils and mononuclear phagocytes predominate. The effect of BG on the secretome of HKL cultures, including secretion of extracellular vesicles (EVs) and soluble protein55s was characterized through western blotting and mass spectrometry. The results demonstrate that, along with upregulation of proinflammatory genes, BG induces secretion of ubiquitinated proteins (UbP), MHCII-containing EVs from professional antigen presenting cells as well as proteins derived from granules of polymorphonuclear granulocytes (PMN). Among the most abundant proteins identified in BG-induced EVs were beta-2 integrin subunits, including CD18 and CD11 homologs, which highlights the role of salmon granulocytes and mononuclear phagocytes in the response to soluble BG. Overall, the current work advances the knowledge about the immunostimulatory activity of yeast BG on the salmon immune system by shedding light on the effect of this PAMP on the secretome of salmon leukocytes.

Factor H-related protein 1 (FHR-1) is associated with atherosclerotic cardiovascular disease

Atherosclerotic cardiovascular disease (ACVD) is a lipid-driven inflammatory disease and one of the leading causes of death worldwide. Lipid deposits in the arterial wall lead to the formation of plaques that involve lipid oxidation, cellular necrosis, and complement activation, resulting in inflammation and thrombosis. The present study found that homozygous deletion of the CFHR1 gene, which encodes the plasma complement protein factor H-related protein 1 (FHR-1), was protective in two cohorts of patients with ACVD, suggesting that FHR-1 accelerates inflammation and exacerbates the disease. To test this hypothesis, FHR-1 was isolated from human plasma and was found to circulate on extracellular vesicles and to be deposited in atherosclerotic plaques. Surface-bound FHR-1 induced the expression of pro-inflammatory cytokines and tissue factor in both monocytes and neutrophils. Notably, plasma concentrations of FHR-1, but not of factor H, were significantly (p < 0.001) elevated in patients with ACVD, and correlated with the expression of the inflammation markers C-reactive protein, apolipoprotein serum amyloid protein A, and neopterin. FHR-1 expression also significantly correlated with plasma concentrations of low-density lipoprotein (LDL) (p < 0.0001) but not high-density lipoprotein (HDL). Taken together, these findings suggest that FHR-1 is associated with ACVD.

Application of Exosomes-Derived Mesenchymal Stem Cells in Treatment of Fungal Diseases: From Basic to Clinical Sciences

Fungal diseases such as candidiasis are some of the deadliest diseases among immunocompromised patients. These fungi naturally exist on human skin and throughout the digestive system. When the microbiota balance becomes upset, these fungi become pathogenic and potentially lethal. At the pathogenesis of fungal diseases, host immune system response is diverse. At the early stages of fungal pathogenesis such as Candida albicans, it was shown that these fungi use the immune cells of the host body and cause malfunction the early induction of proinflammatory cytokines of the host body leading to a reduction in their numbers. However, at some stages of fungal diseases, the immune response is severe. Despite many treatments already being available, it seems that one of the best treatments could be an immune-stimulatory agent. Some of the subsets of MSCs and exosome-derived cells, as a cell-to-cell communicator agent, have many roles in the human body, including anti-inflammatory and immune-modulatory effects. However, the TLR4-primed and IL-17+ subsets of MSCs have been shown to have immune-stimulatory effects. These subsets of the MSCs produce pro-inflammatory cytokines and reduce immunosuppressive cytokines and chemokines. Thus, they could trigger inflammation and stop fungal pathogenesis. As some biological activities and molecules inherit elements of their exosomes from their maternal cells, the exosome-derived TLR4-primed and IL-17+ subsets of MSCs could be a good candidate for fighting against fungal diseases. The applications of exosomes in human diseases are well-known and expanding. It is time to investigate the exosomes application in fungal diseases. In this review, the probable role of exosomes in treating fungal diseases is explored.

Novel Discoveries in Immune Dysregulation in Inborn Errors of Immunity

With the expansion of our knowledge on inborn errors of immunity (IEI), it gradually becomes clear that immune dysregulation plays an important part. In some cases, autoimmunity, hyperinflammation and lymphoproliferation are far more serious than infections. Thus, immune dysregulation has become significant in disease monitoring and treatment. In recent years, the wide application of whole-exome sequencing/whole-genome sequencing has tremendously promoted the discovery and further studies of new IEI. The number of discovered IEI is growing rapidly, followed by numerous studies of their pathogenesis and therapy. In this review, we focus on novel discovered primary immune dysregulation diseases, including deficiency of SLC7A7, CD122, DEF6, FERMT1, TGFB1, RIPK1, CD137, TET2 and SOCS1. We discuss their genetic mutation, symptoms and current therapeutic methods, and point out the gaps in this field.

Activation of Cph1 causes ß(1,3)-glucan unmasking in Candida albicans and attenuates virulence in mice in a neutrophil-dependent manner

Masking the immunogenic cell wall epitope ß(1,3)-glucan under an outer layer of mannosylated glycoproteins is an important virulence factor deployed by Candida albicans during infection. Consequently, increased ß(1,3)-glucan exposure (unmasking) reveals C. albicans to the host's immune system and attenuates its virulence. We have previously shown that activation of the Cek1 MAPK pathway via expression of a hyperactive allele of an upstream kinase (STE11ΔN467) induced unmasking. It also increased survival of mice in a murine disseminated candidiasis model and attenuated kidney fungal burden by ≥33 fold. In this communication, we utilized cyclophosphamide-induced immunosuppression to test if the clearance of the unmasked STE11ΔN467 mutant was dependent on the host immune system. Suppression of the immune response by cyclophosphamide reduced the attenuation in fungal burden caused by the STE11ΔN467 allele. Moreover, specific depletion of neutrophils via 1A8 antibody treatment also reduced STE11ΔN467-dependent fungal burden attenuation, but to a lesser extent than cyclophosphamide, demonstrating an important role for neutrophils in mediating fungal clearance of unmasked STE11ΔN467 cells. In an effort to understand the mechanism by which Ste11ΔN467 causes unmasking, transcriptomics were used to reveal that several components in the Cek1 MAPK pathway were upregulated, including the transcription factor CPH1 and the cell wall sensor DFI1. In this report we show that a cph1ΔΔ mutation restored ß(1,3)-glucan exposure to wild-type levels in the STE11ΔN467 strain, confirming that Cph1 is the transcription factor mediating Ste11ΔN467-induced unmasking. Furthermore, Cph1 is shown to induce a positive feedback loop that increases Cek1 activation. In addition, full unmasking by STE11ΔN467 is dependent on the upstream cell wall sensor DFI1. However, while deletion of DFI1 significantly reduced Ste11ΔN467-induced unmasking, it did not impact activation of the downstream kinase Cek1. Thus, it appears that once stimulated by Ste11ΔN467, Dfi1 activates a parallel signaling pathway that is involved in Ste11ΔN467-induced unmasking.

Pathophysiology and Treatment Options for Hepatic Fibrosis: Can It Be Completely Cured?

Hepatic fibrosis is a dynamic process that occurs as a wound healing response against liver injury. During fibrosis, crosstalk between parenchymal and non-parenchymal cells, activation of different immune cells and signaling pathways, as well as a release of several inflammatory mediators take place, resulting in inflammation. Excessive inflammation drives hepatic stellate cell (HSC) activation, which then encounters various morphological and functional changes before transforming into proliferative and extracellular matrix (ECM)-producing myofibroblasts. Finally, enormous ECM accumulation interferes with hepatic function and leads to liver failure. To overcome this condition, several therapeutic approaches have been developed to inhibit inflammatory responses, HSC proliferation and activation. Preclinical studies also suggest several targets for the development of anti-fibrotic therapies; however, very few advanced to clinical trials. The pathophysiology of hepatic fibrosis is extremely complex and requires comprehensive understanding to identify effective therapeutic targets; therefore, in this review, we focus on the various cellular and molecular mechanisms associated with the pathophysiology of hepatic fibrosis and discuss potential strategies to control or reverse the fibrosis.

Candida albicans Induces Cross-Kingdom miRNA Trafficking in Human Monocytes To Promote Fungal Growth

In response to infections, human immune cells release extracellular vesicles (EVs) that carry a situationally adapted cocktail of proteins and nucleic acids, including microRNAs (miRNAs), to coordinate the immune response. In this study, we identified hsa-miR-21-5p and hsa-miR-24-3p as the most common miRNAs in exosomes released by human monocytes in response to the pathogenic fungus Candida albicans. Functional analysis of miRNAs revealed that hsa-miR-24-3p, but not hsa-miR-21-5p, acted across species and kingdoms, entering C. albicans and inducing fungal cell growth by inhibiting translation of the cyclin-dependent kinase inhibitor Sol1. Packaging of hsa-miR-24-3p into monocyte exosomes required binding of fungal soluble β-glucan to complement receptor 3 (CR3) and binding of mannan to Toll-like receptor 4 (TLR4), resulting in receptor colocalization. Together, our in vitro and in vivo findings reveal a novel cross-species evasion mechanism by which C. albicans exploits a human miRNA to promote fungal growth and survival in the host. IMPORTANCE Over the last decade, communication between immune cells by extracellular vesicle-associated miRNAs has emerged as an important regulator of the coordinated immune response. Therefore, a thorough understanding of the conversation occurring via miRNAs, especially during infection, may provide novel insights into both the host reaction to the microbe as well as the microbial response. This study provides evidence that the pathogenic fungus C. albicans communicates with human monocytes and induces the release of a human miRNA that promotes fungal growth. This mechanism represents an unexpected cross-species interaction and implies that an inhibition of specific miRNAs offers new possibilities for the treatment of human fungal infections.

Fungal Polysaccharides Promote Protective Immunity

Fungal pathogens represent a rising threat against immunocompromised patients. By using Aspergillus fumigatus, Briard et al. showed that the cell wall galactosaminogalactan (GAG) triggers macrophage inflammasome activation, promoting protective immunity. This provides new insights into the role of GAG in host-pathogen interactions and also perspectives for developing GAG-based anti-inflammatory therapeutics.

Asparanin A inhibits cell migration and invasion in human endometrial cancer via Ras/ERK/MAPK pathway

Asparanin A (AA), a natural compound present in vegetables and medicinal herbs like Asparagus officinalis L., has been investigated extensively for its pharmacological attributes. So far, the effect of AA on endometrial cancer (EC) cell migration and invasion has not been explored. Herein, we elucidated the anti-metastasis mechanism of AA on Ishikawa cells based on miRNA-seq and mRNA-seq integrated analyses. AA treatment led to altered miRNAs expression in Ishikawa cells and inhibited the cell wound healing, cell migration and invasion. Gene Ontology and KEGG enrichment analyses showed that the target genes of different expression miRNAs were significantly enriched in Ras, Rap1 and MAPK signaling pathways. Further verification of these changes via qRT-PCR and Western blot assays in vitro and in vivo demonstrated that AA could suppress human EC cell migration and invasion through Ras/ERK/MAPK pathway. Furthermore, top two miRNAs (miR-6236-p5 and miR-12136_R+8) and top three target genes (KITLG, PDGFD, and NRAS) were identified as functional hub miRNAs and genes through miRNA-target gene network analysis. Our data presented a holistic approach to comprehend the anti-metastatic role of AA in EC after in vitro and in vivo analyses.

Immune Sensing of Candida albicans

Candida albicans infections range from superficial to systemic and are one of the leading causes of fungus-associated nosocomial infections. The innate immune responses during these various infection types differ, suggesting that the host environment plays a key role in modulating the host–pathogen interaction. In addition, C. albicans is able to remodel its cell wall in response to environmental conditions to evade host clearance mechanisms and establish infection in niches, such as the oral and vaginal mucosa. Phagocytes play a key role in clearing C. albicans, which is primarily mediated by Pathogen Associated Molecular Pattern (PAMP)–Pattern Recognition Receptor (PRR) interactions. PRRs such as Dectin-1, DC-SIGN, and TLR2 and TLR4 interact with PAMPs such as β-glucans, N-mannan and O-mannan, respectively, to trigger the activation of innate immune cells. Innate immune cells exhibit distinct yet overlapping repertoires of PAMPs, resulting in the preferential recognition of particular Candida morphotypes by them. The role of phagocytes in the context of individual infection types also differs, with neutrophils playing a prominent role in kidney infections, and dendritic cells playing a prominent role in skin infections. In this review, we provide an overview of the key receptors involved in the detection of C. albicans and discuss the differential innate immune responses to C. albicans seen in different infection types such as vulvovaginal candidiasis (VVC) and oral candidiasis.

Curdlan, zymosan and a yeast-derived β-glucan reshape tumor-associated macrophages into producers of inflammatory chemo-attractants

Anti-cancer T-cell responses are often halted due to the immune-suppressive micro-environment, in part related to tumor-associated macrophages. In the current study, we assessed indigestible β-glucans (oatβG, curdlan, grifolan, schizophyllan, lentinan, yeast whole glucan particles (yWGP), zymosan and two additional yeast-derived β-glucans a and b) for their physicochemical properties as well as their effects on the plasticity of human monocyte-derived macrophages that were polarized with IL-4 to immune-suppressive macrophages. Beta-glucans were LPS/LTA free, and tested for solubility, molecular masses, protein and monosaccharide contents. Curdlan, yeast-b and zymosan re-polarized M(IL-4) macrophages towards an M1-like phenotype, in particular showing enhanced gene expression of CCR7, ICAM1 and CD80, and secretion of TNF-α and IL-6. Notably, differential gene expression, pathway analysis as well as protein expressions demonstrated that M(IL-4) macrophages treated with curdlan, yeast-b or zymosan demonstrated enhanced production of chemo-attractants, such as CCL3, CCL4, and CXCL8, which contribute to recruitment of monocytes and neutrophils. The secretion of chemo-attractants was confirmed when using patient-derived melanoma-infiltrating immune cells. Taken together, the bacterial-derived curdlan as well as the yeast-derived β-glucans yeast-b and zymosan have the unique ability to preferentially skew macrophages towards a chemo-attractant-producing phenotype that may aid in anti-cancer immune responses.

Juglone, a novel activator of ferroptosis, induces cell death in endometrial carcinoma Ishikawa cells

Ferroptosis is a novel iron-dependent cell death pathway mainly caused by an abnormal redox state and associated with various diseases including cancer. Recently, much attention has been paid to natural compounds that are involved in its activation and inhibition. This is the first ever study to demonstrate the role of juglone isolated from Carya cathayensis green peel in inducing autophagy and inhibiting endometrial cancer (EC) cell migration. Subsequently, Fe2+ accumulation, lipid peroxidation, GSH depletion, the upregulation of HMOX1, and heme degradation to Fe2+ were reported. Juglone was involved in inducing autophagy and inhibiting cell migration and endoplasmic reticulum stress, which are the new hallmarks of cancer treatment. Collectively, our data indicate that juglone as a functional food ingredient induces the programmed cell death of EC cells by activating oxidative stress and suggest a novel therapeutic approach for the treatment and prevention of EC.

Multi-omics reveals the anticancer mechanism of asparagus saponin-asparanin A on endometrial cancer Ishikawa cells

Multi-omics reveals that AA not only induced apoptosis, but also triggered autophagy in Ishikawa cells through ER stress and DNA damage-related pathways.

Extracellular Vesicles: New Bullets to Fight Fungal Infections

While behaving as a commensal yeast in healthy people, Candida albicans remains the deadliest fungal pathogen in immunocompromised patients. Halder et al. deciphered unprecedented immunomodulatory properties of monocyte extracellular vesicles in response to Candida infections, paving the way to consider therapeutic innovations for fungal infections but also inflammatory diseases.

Candida and Complement: New Aspects in an Old Battle

Candida is a dominant fungal pathogen in immunocompromised hosts, leading to opportunistic infections. Complement with its multifaceted functions is involved in the immune defense against this yeast, and recently several novel aspects have emerged in this old battle. It is clear that Candida can adopt both roles as a colonizer or as a pathogen. In our article, we focus on the molecular mechanisms of the Candida-complement interplay, which occur in disseminated disease as well as locally on skin or on mucous membranes in mouth and vagina; the mechanisms can be supposed to be the same. Activation of the complement system by Candida is facilitated by directly triggering the three dominant pathways, but also indirectly via the coagulation and fibrinolysis systems. The complement-mediated anti-Candida effects induced thereby clearly extend chemotaxis, opsonization, and phagocytosis, and even the membrane attack complex formed on the fungal surface plays a modulatory role, although lysis of the yeast per se cannot be induced due to the thick fungal cell wall. In order to avoid the hostile action of complement, several evasion mechanisms have evolved during co-evolution, comprising the avoidance of recognition, and destruction. The latter comes in many flavors, in particular the cleavage of complement proteins by yeast enzymes and the exploitation of regulatory proteins by recruiting them on the cell wall, such as factor H. The rationale behind that is that the fluid phase regulators on the fungal cell surface down-regulate complement locally. Interestingly, however, evasion protein knockout strains do not necessarily lead to an attenuated disease, so it is likely more complex in vivo than initially thought. The interactions between complement and non-albicans species also deserve attention, especially Candida auris, a recently identified drug-resistant species of medical importance. This is in particular worth investigating, as deciphering of these interactions may lead to alternative anti-fungal therapies directly targeting the molecular mechanisms.