TLRs, NLRs and RLRs: a trinity of pathogen sensors that co-operate in innate immunity

The balance between antiviral and antibacterial responses during M. tuberculosis infection is regulated by the ubiquitin ligase CBL

As a first line of host defense, macrophages must be able to effectively sense and respond to diverse types of pathogens, and while a particular type of immune response may be beneficial in some circumstances, it can be detrimental in others. Upon infecting a macrophage, M. tuberculosis (Mtb) induces proinflammatory cytokines that activate antibacterial responses. Surprisingly, Mtb also triggers antiviral responses that actually hinder the ability of macrophages to control Mtb infection. The ubiquitin ligase CBL suppresses these antiviral responses and shifts macrophages toward a more antibacterial state during Mtb infection, however, the mechanisms by which CBL regulates immune signaling are unknown. We found that CBL controls responses to multiple stimuli and broadly suppresses the expression of antiviral effector genes. We then used mass-spectrometry to investigate potential CBL substrates and identified over 46,000 ubiquitylated peptides in Mtb-infected macrophages, as well as roughly 400 peptides with CBL-dependent ubiquitylation. We then performed genetic interaction analysis of CBL and its putative substrates, and identified the Fas associated factor 2 (FAF2) adapter protein as a key signaling molecule protein downstream of CBL. Together, these analyses identify thousands of new ubiquitin-mediated signaling events during the innate immune response and reveal an important new regulatory hub in this response.

Mayaro virus infection elicits a robust pro-inflammatory and antiviral response in human macrophages

Mayaro virus (MAYV), the etiological agent of Mayaro fever (MAYF), is an emergent arbovirus pathogen belonging to Togaviridae family. MAYF is characterized by high inflammatory component that can cause long-lasting arthralgia that persists for months. Macrophages are viral targets and reservoirs, key components of innate immunity and host response. Given the importance of this pathogen, our aim was to determine the inflammatory and antiviral response of human monocyte-derived macrophages (MDMs) infected with MAYV. First, we established the replication kinetics of the virus. Thereafter, we determined the expression of pattern recognition receptors, NF-ĸB complex, interferons (IFNs), two interleukin 27 (IL27) subunits, IFN-stimulated genes (ISGs), and the production of cytokines/chemokines. We found that human MDMs are susceptible to MAYV infection in vitro, with a peak of viral particles released between 24- and 48-hours post-infection (h.p.i) at MOI 0.5, and between 12 and 24 h.p.i at MOI 1. Interestingly, we observed a significant decline in the production of infectious viral particles at 72 h.p.i that was associated with the induction of antiviral response and high cytotoxic effect of MAYV infection in MDMs. We observed modulation of several genes after MAYV infection, as well, we noted the activation of antiviral detection and response pathways (Toll-like receptors, RIG-I/MDA5, and PKR) at 48 h.p.i but not at 6 h.p.i. Furthermore, MAYV-infected macrophages express high levels of the three types of IFNs and the two IL27 subunits at 48 h.p.i. Moreover, we found higher production of IL6, IL1β, CXCL8/IL8, CCL2, and CCL5 at 48 h.p.i as compared to 6 h.p.i. A robust antiviral response (ISG15, APOBEC3A, IFITM1, and MX2) was observed at 48 but not at 6 h.p.i. The innate and antiviral responses of MAYV-infected MDMs differ at 6 and 48 h.p.i. We conclude that MAYV infection induces robust pro-inflammatory and antiviral responses in human primary macrophages.

Macrophage Ontogeny, Phenotype, and Function in Ischemia Reperfusion-Induced Injury and Repair

AKI is characterized by a sudden, and usually reversible, decline in kidney function. In mice, ischemia-reperfusion injury (IRI) is commonly used to model the pathophysiologic features of clinical AKI. Macrophages are a unifying feature of IRI as they regulate both the initial injury response as well as the long-term outcome following resolution of injury. Initially, macrophages in the kidney take on a proinflammatory phenotype characterized by the production of inflammatory cytokines, such as CCL2 (monocyte chemoattractant protein 1), IL-6, IL-1 β , and TNF- α . Release of these proinflammatory cytokines leads to tissue damage. After resolution of the initial injury, macrophages take on a reparative role, aiding in tissue repair and restoration of kidney function. By contrast, failure to resolve the initial injury results in prolonged inflammatory macrophage accumulation and increased kidney damage, fibrosis, and the eventual development of CKD. Despite the extensive amount of literature that has ascribed these functions to M1/M2 macrophages, a recent paradigm shift in the macrophage field now defines macrophages on the basis of their ontological origin, namely monocyte-derived and tissue-resident macrophages. In this review, we focus on macrophage phenotype and function during IRI-induced injury, repair, and transition to CKD using both the classic (M1/M2) and novel (ontological origin) definition of kidney macrophages.

Septic acute kidney injury and gut microbiome: Should we change our approach?

Incidence of acute kidney injury (AKI) remained relatively stable over the last decade and the adjusted risks for it and mortality are similar across different continents and regions. Also, the mortality of septic-AKI can reach 70% in critically-ill patients. These sole facts can give rise to a question: is there something we do not understand yet? Currently, there are no specific therapies for septic AKI and the treatment aims only to maintain the mean arterial pressure over 65mmHg by ensuring a good fluid resuscitation and by using vasopressors, along with antibiotics. On the other hand, there is an increased concern about the different hemodynamic changes in septic AKI versus other forms and the link between the gut microbiome and the severity of septic AKI. Fortunately, progress has been made in the form of administration of pre- and probiotics, short chain fatty acids (SCFA), especially acetate, and also broad-spectrum antibiotics or selective decontaminants of the digestive tract in a successful attempt to modulate the microbial flora and to decrease both the severity of AKI and mortality. In conclusion, septic-AKI is a severe form of kidney injury, with particular hemodynamic changes and with a strong link between the kidney and the gut microbiome. By modulating the immune response we could not only treat but also prevent severe forms. The most difficult part is to categorize patients and to better understand the key mechanisms of inflammation and cellular adaptation to the injury, as these mechanisms can serve in the future as target therapies.

ADP-Hep-Induced Liquid Phase Condensation of TIFA-TRAF6 Activates ALPK1/TIFA-Dependent Innate Immune Responses

The ALPK1 (alpha-kinase 1)-TIFA (TRAF-interacting protein with fork head-associated domain)-TRAF6 signaling pathway plays a pivotal role in regulating inflammatory processes, with TIFA and TRAF6 serving as key molecules in this cascade. Despite its significance, the functional mechanism of TIFA-TRAF6 remains incompletely understood. In this study, we unveil that TIFA undergoes liquid-liquid phase separation (LLPS) induced by ALPK1 in response to adenosine diphosphate (ADP)-β-D-manno-heptose (ADP-Hep) recognition. The phase separation of TIFA is primarily driven by ALPK1, the pT9-FHA domain, and the intrinsically disordered region segment. Simultaneously, TRAF6 exhibits phase separation during ADP-Hep-induced inflammation, a phenomenon observed consistently across various inflammatory signal pathways. Moreover, TRAF6 is recruited within the TIFA condensates, facilitating lysine (K) 63-linked polyubiquitin chain synthesis. The subsequent recruitment, enrichment, and activation of downstream effectors within these condensates contribute to robust inflammatory signal transduction. Utilizing a novel chemical probe (compound 22), our analysis demonstrates that the activation of the ALPK1-TIFA-TRAF6 signaling pathway in response to small molecules necessitates the phase separation of TIFA. In summary, our findings reveal TIFA as a sensor for upstream signals, initiating the LLPS of itself and downstream proteins. This process results in the formation of membraneless condensates within the ALPK1-TIFA-TRAF6 pathway, suggesting potential applications in therapeutic biotechnology development.

A comprehensive review on the dynamic role of toll-like receptors (TLRs) in frontier aquaculture research and as a promising avenue for fish disease management

Toll-like receptors (TLRs) represent a conserved group of germline-encoded pattern recognition receptors (PRRs) that recognize pathogen-associated molecular patterns (PAMPs) and play a crucial role in inducing the broadly acting innate immune response against pathogens. In recent years, the detection of 21 different TLR types in various fish species has sparked interest in exploring the potential of TLRs as targets for boosting immunity and disease resistance in fish. This comprehensive review offers the latest insights into the diverse facets of fish TLRs, highlighting their history, classification, architectural insights through 3D modelling, ligands recognition, signalling pathways, crosstalk, and expression patterns at various developmental stages. It provides an exhaustive account of the distinct TLRs induced during the invasion of specific pathogens in various fish species and delves into the disparities between fish TLRs and their mammalian counterparts, highlighting the specific contribution of TLRs to the immune response in fish. Although various facets of TLRs in some fish, shellfish, and molluscs have been described, the role of TLRs in several other aquatic organisms still remained as potential gaps. Overall, this article outlines frontier aquaculture research in advancing the knowledge of fish immune systems for the proper management of piscine maladies.

A circRNA therapy based on Rnf103 to inhibit Vibrio anguillarum infection

The losses caused by Vibrio infections in the aquaculture industry are challenging to quantify. In the face of antibiotic resistance, a natural and environmentally friendly alternative is urgently needed. In this study, we identify E3 ubiquitin-protein ligase RNF103 (rnf103) as a crucial target involved in immune evasion by Vibrio anguillarum. Our research demonstrates that Rnf103 promotes immune escape by inhibiting Traf6. Interestingly, we discover a circular RNA (circRNA), circRnf103, formed by reverse splicing of the Rnf103 gene. Predictive analysis and experimentation reveal that circRnf103 encodes Rnf103-177aa, a protein that competes with Rnf103 and binds to Traf6, preventing its degradation. Notably, circRnf103 therapy induces Rnf103-177aa protein production in zebrafish. In zebrafish models, circRnf103 exhibits significant effectiveness in treating V. anguillarum infections, reducing organ burden. These findings highlight the potential of circRNA therapy as a natural and innovative approach to combat infectious diseases sustainably, particularly in aquaculture and environmental management.

circCBL and its host gene CBL collaboratively enhance the antiviral immunity and antibacterial immunity by targeting MITA in fish

IMPORTANCE

Increasing evidence indicates that circular RNAs exert crucial functions in regulating gene expression in mammals. However, the function of circRNAs in lower vertebrates still needs further exploration. Our research results demonstrated that circRNA, namely circCBL, is involved in modulating antiviral and antibacterial immune responses in lower vertebrates. In addition, our study also found that circCBL can serve as a competing endogenous RNA to facilitate MITA expression, thereby modulating MITA-mediated innate immunity. Further research has proved that the host gene CBL also promotes the expression of MITA, enhancing antiviral and antibacterial immune responses. Our study not only elucidated the underlying biological mechanism of the circRNA-miRNA-mRNA axis in the innate immune response of lower vertebrates but also unveiled the synergistic antibacterial and antiviral mechanisms between circRNA and its host gene in lower vertebrates.

Use of single-cell technology to improve our understanding of the role of TLR2 in macrophage-Mycobacterium tuberculosis interaction

The interaction between Mycobacterium tuberculosis, the agent of tuberculosis (TB), and its host cell, the macrophage, is multifaceted, dynamic, and involves multiple molecular partners. A better understanding of this interaction could help researchers manipulate the immune system in order to design host-targeted immunotherapies and/or develop a novel vaccine protecting better adults against TB. Jani and coworkers studied the role of the macrophage receptor TLR2 in the response to M. tuberculosis using single-cell technologies (C. Jani, S. L. Solomon, J. M. Peters, and S. C. Pringle, et al., mSystems, https://doi.org/10.1128/msystems.00052-23, 2023). This work addresses the multiple challenges associated with such studies and shows how informative single-cell analysis can be for the study of heterogeneous and complex host-pathogen interactions.

RNA modification in mRNA cancer vaccines

RNA modification is manifested as chemically altered nucleotides, widely exists in diverse natural RNAs, and is closely related to RNA structure and function. Currently, mRNA-based vaccines have received great attention and rapid development as novel and mighty fighters against various diseases including cancer. The achievement of RNA vaccines in clinical application is largely attributed to some methodological innovations including the incorporation of modified nucleotides into the synthetic RNA. The selection of optimal RNA modifications aimed at reducing the instability and immunogenicity of RNA molecules is a very critical task to improve the efficacy and safety of mRNA vaccines. This review summarizes the functions of RNA modifications and their application in mRNA vaccines, highlights recent advances of mRNA vaccines in cancer immunotherapy, and provides perspectives for future development of mRNA vaccines in the context of personalized tumor therapy.

Isolation, Identification, Anti-Inflammatory, and In Silico Analysis of New Lignans from the Resin of Ferula sinkiangensis

Ferula sinkiangensis K. M. Shen (Apiaceae) is distributed in arid desert areas of Xinjiang, and its resin is a traditional Chinese medicine to treat gastrointestinal digestive diseases. To explore bioactive components from F. sinkiangensis, three new lignans and thirteen known components were isolated. The structural elucidation of the components was established utilizing spectroscopic analyses together with ECD calculations. Griess reaction results indicated new compounds 1 and 2 significantly decreased NO production in LPS-stimulated RAW 264.7 macrophages, and ELISA results indicated that they effectively attenuated LPS-induced inflammation by inhibiting TNF-α, IL-1β, and IL-6 expressions. The in silico approach confirmed that compound 1 docked into the receptors with strong binding energies of -5.84~-10.79 kcal/mol. In addition, compound 6 inhibited the proliferation of AGS gastric cancer cells with IC50 values of 15.2 μM by suppressing the cell migration and invasion. This study disclosed that F. sinkiangensis might be a promising potential resource for bioactive components.

Immune-Stimulating Potential of Lacticaseibacillus rhamnosus LM1019 in RAW 264.7 Cells and Immunosuppressed Mice Induced by Cyclophosphamide

Probiotics, including Lacticaseibacillus rhamnosus (L. rhamnosus), have gained recognition for their potential health benefits, such as enhancing immune function, maintaining gut health, and improving nutrient absorption. This study investigated the effectiveness of L. rhamnosus LM1019 (LM1019) in enhancing immune function. In RAW 264.7 cells, LM1019 demonstrated dose-dependent immune stimulation by increasing nitric oxide production, gene expression of proinflammatory cytokines, and the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). These effects were mediated through the activation of mitogen-activated protein kinases (MAPKs) and nuclear factor-kappa B (NF-κB) translocation without inducing cytotoxicity. Furthermore, orally administered LM1019 was evaluated in immunosuppressed mice induced by cyclophosphamide (CTX). High-dose administration of LM1019 significantly increased the subpopulations of lymphocytes, specifically helper T cells (CD4+), as well as two subtypes of natural killer (NK) cells, namely, IFN-γ+ and granzyme B+ NK cells. Additionally, LM1019 at a high dose led to elevated levels of proinflammatory cytokines, including IFN-γ and IL-12, compared to CTX-treated mice. These findings highlight the potential of LM1019 in enhancing the immune system. The study contributes to the growing body of research on the beneficial effects of probiotics on immune function.

Harnessing Nanomaterials for Cancer Sonodynamic Immunotherapy

Immunotherapy has made remarkable strides in cancer therapy over the past decade. However, such emerging therapy still suffers from the low response rates and immune-related adverse events. Various strategies have been developed to overcome these serious challenges. Therein, sonodynamic therapy (SDT), as a non-invasive treatment, has received ever-increasing attention especially in the treatment of deep-seated tumors. Significantly, SDT can effectively induce immunogenic cell death to trigger systemic anti-tumor immune response, termed sonodynamic immunotherapy. The rapid development of nanotechnology has revolutionized SDT effects with robust immune response induction. As a result, more and more innovative nanosonosensitizers and synergistic treatment modalities are established with superior efficacy and safe profile. In this review, the recent advances in cancer sonodynamic immunotherapy are summarized with a particular emphasis on how nanotechnology can be explored to harness SDT for amplifying anti-tumor immune response. Moreover, the current challenges in this field and the prospects for its clinical translation are also presented. It is anticipated that this review can provide rational guidance and facilitate the development of nanomaterials-assisted sonodynamic immunotherapy, helping to pave the way for next-generation cancer therapy and eventually achieve a durable response in patients.

Veillonella parvula promotes the proliferation of lung adenocarcinoma through the nucleotide oligomerization domain 2/cellular communication network factor 4/nuclear factor kappa B pathway

Enrichment of Veillonella parvula in the lung microbiota is strongly associated with non-small cell lung cancer (NSCLC) and induces the progression of lung adenocarcinoma in vivo, but its actual role and mechanism remain unexplored. This study analyzed the correlation between NSCLC and V. parvula abundance based on 16 s rRNA sequencing results. The effects of V. parvula on the progression of lung adenocarcinoma were observed in vivo and in vitro using a C57 bl/6j mouse tumor-bearing model, a bacterial cell co-culture model, combined with transcriptome sequencing, and a TCGA database to explore and validate the growth promotion of lung adenocarcinoma by V. parvula and its molecular mechanism. 16 s rRNA sequencing revealed that V. parvula was significantly enriched in lung adenocarcinoma. In vivo, V. parvula promoted the growth of lung adenocarcinoma in mice by suppressing the infiltration of tumor-associated T lymphocytes and peripheral T lymphocytes. It showed a higher affinity for lung adenocarcinoma in vitro and promoted lung adenocarcinoma cell proliferation through adhesion or intracellular invasion. Further analysis of differential gene expression and KEGG enrichment by transcriptome sequencing revealed that V. parvula induced CCN4 expression and activated NOD-like receptor and NF-κB signaling pathway in lung adenocarcinoma cells. Further analysis clarified that V. parvula promoted activation of the NF-κB pathway via Nod2/CCN4 signaling, which promoted lung adenocarcinoma cell proliferation. Thus, V. parvula mediates activation of the Nod2/CCN4/NF-κB signaling pathway to promote non-small cell lung adenocarcinoma progression, thereby providing a potential target for diagnosing and treating lung adenocarcinoma.

Association of IFIH1 and DDX58 genes polymorphism with susceptibility to COVID-19

Pattern recognition receptors of the innate immune system, such as RIG-I and MDA5, are responsible for recognizing viruses and inducing interferon production. Genetic polymorphisms in the coding regions of RLR may be associated with the severity of COVID-19. Considering the contribution of the RLR signaling in immune-mediated reactions, this study investigated the association between three SNP in the coding region of IFIH1 and DDX58 genes with the susceptibility to COVID-19 in the Kermanshah population, Iran. 177 patients with severe and 182 with mild COVID-19 were admitted for this study. Genomic DNA was extracted from peripheral blood leukocytes of patients to determine the genotypes of two SNPs, rs1990760(C>T) and rs3747517(T>C) IFIH1 gene and rs10813831(G>A) DDX58 gene using PCR-RFLP method. Our results showed that the frequency of the AA genotype of rs10813831(G>A) was associated with susceptibility to COVID-19 compared to the GG genotype (p = 0.017, OR = 2.593, 95% CI 1.173-5.736). We also observed a statistically significant difference in the recessive model for SNPs rs10813831 variant (AA versus GG + GA, p = 0.003, OR = 2.901, 95% CI 1.405-6.103). Furthermore, No significant association was found between rs1990760 (C>T) and rs3747517(T>C) of IFIH1 gene polymorphisms with COVID-19. Our findings suggest that DDX58 rs10813831(A>G) polymorphism may be associated with COVID-19 severity in the Kermanshah population, Iran.

Characterization analysis of TLR5a and TLR5b immune response after different bacterial infection in grass carp (Ctenopharyngodon idella)

Toll-like receptor (TLR) is an important pattern recognition receptor, which specifically recognizes microbial components, and TLR5 recognizes bacterial flagellin in vertebrates and invertebrates. In this study, two forms of TLR5 (TLR5a and TLR5b) were identified in grass carp (Ctenopharyngodon idella). Aeromonas hydrophila and Staphylococcus aureus were used to investigate the role of grass carp TLR5a and TLR5b against bacteria (flagellate and non-flagellate) in innate immunity, and the expression of TLR5a and TLR5b genes and proteins were detected in immune-related tissues. Quantitative real-time polymerase chain reaction results showed that TLR5a and TLR5b genes of grass carp were highly expressed in the liver, spleen, and head kidney, and their expression patterns were similar in tissues. Meanwhile, the TLR5b gene expression was higher than TLR5a in most tissues. Following exposure to A. hydrophila and S. aureus, the expression levels of TLR5a and TLR5b genes in the liver, spleen, and head kidney were up-regulated significantly. Moreover, the downstream gene, NF-κB, was up-regulated significantly. After A. hydrophila infection, the expression of TLR5a gene was up-regulated in the liver and spleen at 24 h, while TLR5b was up-regulated at 6 h. In the head kidney, TLR5a was up-regulated at 6 h, while TLR5b was up-regulated at 6 h and 12 h. After S. aureus infection, TLR5a and TLR5b were up-regulated at 6 h in the liver and 12 h in the spleen. However, in the head kidney, TLR5a was down-regulated, while TLR5b was up-regulated. Compared with TLR5a, TLR5b had a higher expression level and stronger response to pathogen stimulation. The immunofluorescence results showed that TLR5a and TLR5b proteins in the liver of grass carp infected with A. hydrophila and S. aureus were similar but different in the spleen and head kidney. The results indicated that TLR5a and TLR5b play a critical role in resisting bacterial infection, and TLR5a and TLR5b had obvious tissue and pathogen specificity. TLR5b may play a major role in immune tissues, while TLR5a may play an auxiliary regulatory role in early infection. In addition, TLR5a and TLR5b have an irreplaceable regulatory role in response to flagellate and non-flagellate bacteria. This lays a foundation to explore further the role of TLR5 in resisting flagellate and non-flagellate infections in fish and provides a reference for the innate immunity research of grass carp.

Innate immune receptors co-recognition of polysaccharides initiates multi-pathway synergistic immune response

The law and mechanism of the interaction between polysaccharides and pattern recognition receptors (PRRs) has been unclear. Herein, three glucomannans with different structures were selected to explore the universal mechanism for PRRs to recognize glucomannans. Screening results showed that the silence of TLR4 but not TLR2 severely blocked the production of inflammatory cytokines and the transduction of signal pathways. In-depth results revealed that the participation of myeloid differentiation protein 2 (MD2) and CD14 and the dimerization of the TLR4-MD2 complex were required for glucomannan-activated TLR4 signal transduction. Mannose receptor (MR) was also engaged in glucomannan-induced respiratory burst, endocytosis, and inflammatory signaling pathways in a spleen tyrosine kinase-dependent manner. The internalization of glucomannans into the cytoplasm by MR directly initiated complex intracellular signaling cascades. Finally, molecular docking characterized the binding energy and binding sites between glucomannans and multiple receptors from other perspectives. The essence of glucomannans recognized by PRRs was the non-covalent interaction of multiple receptors and the subsequent transmission of the signal cascade was triggered in a multi-channel and cooperative manner. As a result, the hypothesis that "Innate immune receptors co-recognition of polysaccharides initiates multi-pathway synergistic immune response" was proposed to outline these meaningful phenomena.

Disease mechanisms as subtypes: Microbiome

Abnormalities in gut microbiota have been suggested to be involved in the pathophysiology and progression of Parkinson's disease (PD). Gastrointestinal nonmotor symptoms often precede the onset of motor features in PD, suggesting a role for gut dysbiosis in neuroinflammation and α-synuclein (α-syn) aggregation. In the first part of this chapter, we analyze critical features of healthy gut microbiota and factors (environmental and genetic) that modify its composition. In the second part, we focus on the mechanisms underlying the gut dysbiosis and how it alters anatomically and functionally the mucosal barrier, triggering neuroinflammation and subsequently α-syn aggregation. In the third part, we describe the most common alterations in the gut microbiota of PD patients, dividing the gastrointestinal system in higher and lower tract to examine the association between microbiota abnormalities and clinical features. In the final section, we report on current and future therapeutic approaches to gut dysbiosis aiming to either reduce the risk for PD, modify the disease course, or improve the pharmacokinetic profile of dopaminergic therapies. We also suggest that further studies will be needed to clarify the role of the microbiome in PD subtyping and of pharmacological and nonpharmacological interventions in modifying specific microbiota profiles in individualizing disease-modifying treatments in PD.

Circular RNA circPlce1 regulates innate immune response in miiuy croaker, Miichthys miiuy

In recent years, more and more researchers have devoted to the study of circular RNAs (circRNAs) in noncoding RNAs. As an important regulator in a variety of biological processes, circRNAs are relatively abundant in the study of mammals, while research in lower vertebrates is still lacking. In this study, we found a circRNA, circPlce1, related to innate immune response in Miichthys miiuy (miiuy croaker). The experimental results confirmed that circPlce1 could promote the production of antiviral genes and inflammatory response under the stimulation of poly (I: C) and LPS. We also confirmed that circPlce1 can promote NF-κB and IRF3 pathways through luciferase reporter assay experiment. In addition, we also found that circPlce1 can promote cell proliferation and improve cell viability. In conclusion, our results showed that circPlce1 plays an active role in regulating inflammatory response, cell proliferation and cell viability, providing a foundation for the study of the biological function of circRNAs in the innate immune response in teleost fish.

Relationship between histopathological lesions and oxidative stress in mice infected with Angiostrongylus costaricensis

This study describes changes in oxidative stress (OS) parameters in mice experimentally infected with Angiostrongylus costaricensis, which causes abdominal angiostrongyliasis. For this, 28 Swiss mice were used, divided into two groups (G1 and G2), with 14 animals each. Of these, eight were infected with ten infective larvae each, by gavage, and six were used as a control group. Mice from G1 and G2 were euthanized at 14 days and 24 days post-infection, respectively. Tissue samples were used for histopathological analysis and blood (serum) samples were taken to assess the levels of proteins, non-protein thiols (NPTs) and nitric oxide (NO), from centrifugation and subsequent collection of aliquots of the supernatant. Among OS parameters, infected mice in both groups had higher NO levels than the control group, due to the presence of: eosinophil infiltrate in the liver and intestine; pancreatitis; and intestinal granuloma. However, the infected mice of both groups showed a reduction in the levels of NPTs, in relation to the control group, due to the presence of: eosinophilic infiltrate in the liver and intestine; and intestinal granuloma. Our results suggest that A. costaricensis infection has important effects on the intestine, liver and pancreas, and the analyses were performed from the tissue of these organs. The mechanisms for these changes are related to the decrease in the body's main antioxidant defences, as demonstrated by the reduction of NPTs, thus contributing to the development of more severe tissue damage. Thus, the objective of the present study was to evaluate the relationship between histopathological lesions and markers for OS.

Toll-like Receptor 4 in Acute Kidney Injury

Acute kidney injury (AKI) is a common and devastating pathologic condition, associated with considerable high morbidity and mortality. Although significant breakthroughs have been made in recent years, to this day no effective pharmacological therapies for its treatment exist. AKI is known to be connected with intrarenal and systemic inflammation. The innate immune system plays an important role as the first defense response mechanism to tissue injury. Toll-like receptor 4 (TLR4) is a well-characterized pattern recognition receptor, and increasing evidence has shown that TLR4 mediated inflammatory response, plays a pivotal role in the pathogenesis of acute kidney injury. Pathogen-associated molecular patterns (PAMPS), which are the conserved microbial motifs, are sensed by these receptors. Endogenous molecules generated during tissue injury, and labeled as damage-associated molecular pattern molecules (DAMPs), also activate pattern recognition receptors, thereby offering an understanding of sterile types of inflammation. Excessive, uncontrolled and/or sustained activation of TLR4, may lead to a chronic inflammatory state. In this review we describe the role of TLR4, its endogenous ligands and activation in the inflammatory response to ischemic/reperfusion-induced AKI and sepsis-associated AKI. The potential regeneration signaling patterns of TLR4 in acute kidney injury, are also discussed.

Transcriptome sequencing reveals improved ammonia nitrogen tolerance in Zebra II strain of the Manila clam Ruditapes philippinarum

In this research, we identified genes associated with ammonia nitrogen (TAN) stress response and resistance in juveniles of the Zebra II strain and a wild population of the Manila clam Ruditapes philippinarum. Both groups were subjected to a 96 h acute toxicity test using TAN concentrations of 17.617 ± 0.634 and 16.670 ± 0.7 mg/l, respectively. We then collected samples, conducted transcriptome sequencing and screened the sequences for differentially expressed genes (DEGs) related to TAN stress response. We identified 2908 and 2861 DEGs in the Zebra II and wild clam groups, respectively, and the two groups had 626 DEGs in common. The verified DEGs had less of a detoxification effect in the wild population than that in the Zebra II group. Gene Ontology database analysis showed that Zebra II juveniles were mainly enriched in protein phosphorylation, purine nucleoside binding, and kinase activity, whereas the wild population juveniles were primarily enriched in oxidases activity, organic acid metabolic processes, and extracellular regions. Kyoto Encyclopedia of Genes and Genomes pathway analysis mainly highlighted aminoacyl tRNA biosynthesis in Zebra II juveniles and sphingolipid metabolism, FOXO signaling, biosynthesis of aminoacyl tRNA, and other pathways in the wild population. These results show that the toxic effect of TAN on the Manila clam is related to a variety of pathways, which are mainly related to immune response, inflammatory response, metabolic pathways, and nerve conduction. This study provides basic data and theoretical reference for revealing the molecular regulation mechanism of the improved TAN tolerance of Zebra II strain as compared with the wild population of Ruditapes philippinarum.

Autophagic reprogramming of bone marrow–derived macrophages

Macro-autophagy is a highly conserved catabolic process among eukaryotes affecting macrophages. This work studies the genetic regulatory network involving the interplay between autophagy and macrophage polarization (activation). Autophagy-related genes (Atgs) and differentially expressed genes (DEGs) of macrophage polarization (M1–M2) were predicted, and their regulatory networks constructed. Naïve (M0) mouse bone marrow–derived monocytes were differentiated into M1 and M2a. Validation of the targets of Smad1, LC3A and LC3B, Atg16L1, Atg7, IL-6, CD68, Arg-1, and Vamp7 was performed in vitro. Immunophenotyping by flow cytometry revealed three macrophage phenotypes: M0 (IL-6 + /CD68 +), M1 (IL-6 + /CD68 + /Arg-1 +), and M2a (CD68 + /Arg-1). Confocal microscopy revealed increased autophagy in both M1 and M2a and a significant increase in the pre-autophagosomes size and number. Bafilomycin A increased the expression of CD68 and Arg-1 in all cell lineages. In conclusion, our approach predicted the protein targets mediating the interplay between autophagy and macrophage polarization. We suggest that autophagy reprograms macrophage polarization via CD68, arginase 1, Atg16L1-1, and Atg16L1-3. The current findings provide a foundation for the future use of macrophages in immunotherapy of different autoimmune disorders.

Transcriptome profiling based on protein-protein networks provides a core set of genes for understanding blood immune response mechanisms against LPS stress in Amphioctopus fangsiao

Gram-negative bacteria are significant pathogens in the ocean, posing serious threats to marine organisms. Lipopolysaccharide (LPS) is a characteristic chemical constituent in Gram-negative bacteria that can be recognized by the pattern recognition receptor (PRR) of immune cells. This system is often used to simulate the invasion of bacteria. Blood is a transport channel for immune cells, and its transcriptome information obtained from Amphioctopus fangsiao stimulated by LPS is essential for understanding the antibacterial biological mechanisms of this species. In this study, we analyzed the gene expression profiles of A. fangsiao blood within 24h under LPS stress and found 778 and 561 differentially expressed genes (DEGs) at 6 and 24h, respectively. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment analyses were performed to search for immune-related DEGs. The relationships among immune genes were examined by constructing a protein-protein interaction (PPI) network. Finally, 16 hub genes were identified based on the PPI network and KEGG enrichment analysis. The expression profiles of these genes were verified using quantitative RT-PCR (qRT-PCR). This research provides valuable resources for the healthy culture of A. fangsiao and helps us understand the molecular mechanisms of innate immunity.

Tumor Necrosis Factor: What Is in a Name?

Tumor Necrosis Factor was one of the first cytokines described in the literature as a soluble mediator of cytotoxicity to tumors. Over the years, more extensive research that tried to employ Tumor Necrosis Factor in cancer treatments showed nevertheless that it mainly functioned as a proinflammatory cytokine. However, this did not stop the search for the holy grail of cancer research: A cytokine that could act as a one-stop treatment for solid tumors and lymphomas. This review will summarize the long experimental history of Tumor Necrosis Factor that caused the initial observations of a tumor necrotizing cytokine that could serve as a potential cancer treatment and discuss the current state of research into this side of the activities of Tumor Necrosis Factor.

Detection of innate immune response modulating impurities (IIRMI) in therapeutic peptides and proteins: Impact of excipients

Unintended immunogenicity can affect the safety and efficacy of therapeutic proteins and peptides, so accurate assessments of immunogenicity risk can aid in the selection, development, and regulation of biologics. Product- and process- related impurities can act as adjuvants that activate the local or systemic innate immune response increasing the likelihood of product immunogenicity. Thus, assessing whether products have innate immune response modulating impurities (IIRMI) is a key component of immunogenicity risk assessments. Identifying trace levels of individual IIRMI can be difficult and testing individually for all potential impurities is not feasible. Therefore, to mitigate the risk, cell-based assays that use human blood cells or monocyte-macrophage reporter cell lines are being developed to detect minute quantities of impurities capable of eliciting innate immune activation. As these are cell-based assays, there is concern that excipients could blunt the cell responses, masking the presence of immunogenic IIRMI. Here, we explore the impact of frequently used excipients (non-ionic detergents, sugars, amino acids, bulking agents) on the sensitivity of reporter cell lines (THP-1- and RAW-Blue cells) and fresh human blood cells to detect purified TLR agonists as model IIRMI. We show that while excipients do not modulate the innate immune response elicited by TLR agonists in vivo, they can impact on the sensitivity of cell-based IIRMI assays. Reduced sensitivity to detect LPS, FSL-1, and other model IIRMI was also evident when testing 3 different recombinant drug products, product A (a representative mAb), B (a representative growth factor), C (a representative peptide), and their corresponding formulations. These results indicate that product formulations need to be considered when developing and validating cell-based assays for assessing clinically relevant levels of IIRMI in therapeutic proteins. Optimization of reporter cells, culture conditions and drug product concentration appear to be critical to minimize the impact of excipients and attain sensitive and reproducible assays.

The Pathophysiology of Sepsis-Associated AKI

Sepsis-associated AKI is a life-threatening complication that is associated with high morbidity and mortality in patients who are critically ill. Although it is clear early supportive interventions in sepsis reduce mortality, it is less clear that they prevent or ameliorate sepsis-associated AKI. This is likely because specific mechanisms underlying AKI attributable to sepsis are not fully understood. Understanding these mechanisms will form the foundation for the development of strategies for early diagnosis and treatment of sepsis-associated AKI. Here, we summarize recent laboratory and clinical studies, focusing on critical factors in the pathophysiology of sepsis-associated AKI: microcirculatory dysfunction, inflammation, NOD-like receptor protein 3 inflammasome, microRNAs, extracellular vesicles, autophagy and efferocytosis, inflammatory reflex pathway, vitamin D, and metabolic reprogramming. Lastly, identifying these molecular targets and defining clinical subphenotypes will permit precision approaches in the prevention and treatment of sepsis-associated AKI.

TRIM56 overexpression restricts porcine epidemic diarrhoea virus replication in Marc-145 cells by enhancing TLR3-TRAF3-mediated IFN-β antiviral response

Infection with the porcine epidemic diarrhoea virus (PEDV) causes severe enteric disease in suckling piglets, causing massive economic losses in the swine industry worldwide. Tripartite motif-containing 56 (TRIM56) has been shown to augment type I IFN response, but whether it affects PEDV replication remains uncharacterized. Here we investigated the role of TRIM56 in Marc-145 cells during PEDV infection. We found that TRIM56 expression was upregulated in cells infected with PEDV. Overexpression of TRIM56 effectively reduced PEDV replication, while knockdown of TRIM56 resulted in increased viral replication. TRIM56 overexpression significantly increased the phosphorylation of IRF3 and NF-κB P65, and enhanced the IFN-β antiviral response, while silencing TRIM56 did not affect IRF3 activation. TRIM56 overexpression increased the protein level of TRAF3, the component of the TLR3 pathway, thereby significantly activating downstream IRF3 and NF-κB signalling. We demonstrated that TRIM56 overexpression inhibited PEDV replication and upregulated expression of IFN-β, IFN-stimulated genes (ISGs) and chemokines in a dose-dependent manner. Moreover, truncations of the RING domain, N-terminal domain or C-terminal portion on TRIM56 were unable to induce IFN-β expression and failed to restrict PEDV replication. Together, our results suggested that TRIM56 was upregulated in Marc-145 cells in response to PEDV infection. Overexpression of TRIM56 inhibited PEDV replication by positively regulating the TLR3-mediated antiviral signalling pathway. These findings provide evidence that TRIM56 plays a positive role in the innate immune response during PEDV infection.

Evolution of toll-like receptor gene family in amphibians

The evolutionary position and lifestyle of amphibians highlights the important roles of the immune system in adaptive radiation and their adaptation to a complex pathogenic environment. Toll-like receptors (TLRs) are membrane-like sensors that recognize and bind conserved molecular motifs in pathogens to initiate downstream immune responses. To understand the evolutionary patterns of TLRs in amphibians, we analyzed TLR genes from the genomes and transcriptomes of 102 amphibian species. Phylogenetic results showed that 578 intact amphibian TLR sequences belonged to 16 TLR genes and were divided into seven subfamilies. The TLR4 subfamily was only identified in the Anura. Purification selection plays a leading role in amphibian TLR evolution and mean ω (dN/dS) values ranged from 0.252 for TLR7 to 0.381 for TLR19. Furthermore, the ω values of different domains were significantly different. We found positive selection patterns for 141 of 12,690 codons (1.1%) in all amphibian TLRs, most of which were located in leucine-rich repeats (LRRs). We also observed low to moderate levels of single-nucleotide polymorphisms (SNPs) in Pelophylax nigromaculatus and Bombina orientalis. This study provided critical primers, meaningful information regarding TLR gene family evolution in amphibians, and insights into the complex evolutionary patterns and implications of TLR polymorphisms.

Differential Effect of Dietary Fibers in Intestinal Health of Growing Pigs: Outcomes in the Gut Microbiota and Immune-Related Indexes

Although dietary fibers (DFs) have been shown to improve intestinal health in pigs, it is unclear whether this improvement varies according to the type/source of DF. In the current study, we investigated the impact of dietary supplement (15%) of pea-hull fiber (PF), oat bran (OB), and their mixture (MIX, PF, and OB each accounted for 7.5%) in the growth performance as well as intestinal barrier and immunity-related indexes in growing pigs. Twenty-four cross-bred pigs (32.42 ± 1.95 kg) were divided into four groups: CON (basal diet with no additional DF), PF, OB, and MIX. After 56 days of feeding, we found that the growth performance of PF pigs was decreased (p < 0.05) compared with pigs in other groups. Results of real-time polymerase chain reaction and Western blot showed that the improvement of immune-related indexes (e.g., interleukin 10 [IL-10]) in OB and MIX pigs mainly presented in the ileum, whereas the improvement of intestinal barrier–related indexes (e.g., MUC1 and MUC2) mainly presented in the colon. Whether in the ileum or colon, such improvement of immune function may be dependent on NOD rather than TLR-associated pathways. Amplicon sequencing results showed that PF and MIX pigs shared a similar bacterial community, such as lower abundance of ileal Clostridiaceae and colonic Streptoccocus than that of CON pigs (p < 0.05). Our results indicate that OB and MIX, rather than PF, benefit the intestinal health in growing pigs, and multiple-sourced DF may reduce the adverse effect of single-soured DF on the growth performance and gut microbiota in pigs.

Peramivir, an Anti-Influenza Virus Drug, Exhibits Potential Anti-Cytokine Storm Effects

Coronavirus Disease 2019 (COVID-19) infected by Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) has been declared a public health emergency of international concerns. Cytokine storm syndrome (CSS) is a critical clinical symptom of severe COVID-19 patients, and the macrophage is recognized as the direct host cell of SARS-CoV-2 and potential drivers of CSS. In the present study, peramivir was identified to reduce TNF-α by partly intervention of NF-κB activity in LPS-induced macrophage model. In vivo, peramivir reduced the multi-cytokines in serum and bronchoalveolar lavage fluid (BALF), alleviated the acute lung injury and prolonged the survival time in mice. In human peripheral blood mononuclear cells (hPBMCs), peramivir could also inhibit the release of TNF-α. Collectively, we proposed that peramivir might be a candidate for the treatment of COVID-19 and other infections related CSS.

The long noncoding RNA MIR122HG is a precursor for miR-122-5p and negatively regulates the TAK1-induced innate immune response in teleost fish

Long noncoding RNAs (lncRNAs) are a diverse subset of RNA species of noncoding transcripts that are usually longer than 200 nt. However, the biological role and function of many lncRNAs have not been fully identified. It has been shown that one potential function of lncRNAs is to act as a precursor miRNA and promote the production of multiple miRNAs. However, the function of the miiuy croaker lncRNA MIR122HG has not been explored. In the present study, we show that this differentially expressed teleost fish lncRNA can act as the host gene of miR-122-5p, regulate its expression, and indirectly regulate the expression of potential inflammatory target protein transforming growth factor-β–activated kinase 1. We show that MIR122HG can negatively regulate the transforming growth factor-β–activated kinase 1–triggered NF-κB and interferon regulatory factor 3 signaling pathways and subsequently attenuate the innate immune response. In addition, MIR122HG can promote the replication of Siniperca chuatsi rhabdovirus and exacerbate the pathological effects caused by viral infection. We conclude that the study of lncRNA–miRNA–mRNA interaction through bioinformatics analysis or experimental-supported analysis can provide information for further elucidation of the functions of fish lncRNAs in innate immunity.

The Emerging Role of RNA Modifications in the Regulation of Antiviral Innate Immunity

Posttranscriptional modifications have been implicated in regulation of nearly all biological aspects of cellular RNAs, from stability, translation, splicing, nuclear export to localization. Chemical modifications also have been revealed for virus derived RNAs several decades before, along with the potential of their regulatory roles in virus infection. Due to the dynamic changes of RNA modifications during virus infection, illustrating the mechanisms of RNA epigenetic regulations remains a challenge. Nevertheless, many studies have indicated that these RNA epigenetic marks may directly regulate virus infection through antiviral innate immune responses. The present review summarizes the impacts of important epigenetic marks on viral RNAs, including N6-methyladenosine (m⁶A), 5-methylcytidine (m⁵C), 2ʹ-O-methylation (2ʹ-O-Methyl), and a few uncanonical nucleotides (A-to-I editing, pseudouridine), on antiviral innate immunity and relevant signaling pathways, while highlighting the significance of antiviral innate immune responses during virus infection.

Biocompatibility in vivo of elastic cartilage treated in alkaline solutions

ABSTRACT This study verified the in vivo biocompatibility of bovine elastic cartilage decellularized with alkaline solution in relation to the non-decellularized cartilage implanted in rats. Fifty Wistar rats were divided into two groups, with the experimental group (EG) receiving subcutaneous implants of cartilage treated in alkaline solution and the control group (CG) receiving subcutaneous implants of untreated cartilage. In both groups, the implants were removed on days 3, 7, 14, 21 and 42 with the preparation of histological slides stained with Hematoxylin and Eosin for the quantification of inflammatory cells, fibroblasts, angiogenesis, and cartilage degradation. The results showed that EG presented a less intense inflammatory infiltrate and better organization of collagen fibers compared to CG. It was concluded that the alkaline treatment provided better biocompatibility for elastic cartilage when implanted subcutaneously in rats.

Infection in the Developing Brain: The Role of Unique Systemic Immune Vulnerabilities

Central nervous system (CNS) infections remain a major burden of pediatric disease associated with significant long-term morbidity due to injury to the developing brain. Children are susceptible to various etiologies of CNS infection partly because of vulnerabilities in their peripheral immune system. Young children are known to have reduced numbers and functionality of innate and adaptive immune cells, poorer production of immune mediators, impaired responses to inflammatory stimuli and depressed antibody activity in comparison to adults. This has implications not only for their response to pathogen invasion, but also for the development of appropriate vaccines and vaccination strategies. Further, pediatric immune characteristics evolve across the span of childhood into adolescence as their broader physiological and hormonal landscape develop. In addition to intrinsic vulnerabilities, children are subject to external factors that impact their susceptibility to infections, including maternal immunity and exposure, and nutrition. In this review we summarize the current evidence for immune characteristics across childhood that render children at risk for CNS infection and introduce the link with the CNS through the modulatory role that the brain has on the immune response. This manuscript lays the foundation from which we explore the specifics of infection and inflammation within the CNS and the consequences to the maturing brain in part two of this review series.

Insights into Modern Therapeutic Approaches in Pediatric Acute Leukemias

Pediatric cancers predominantly constitute lymphomas and leukemias. Recently, our knowledge and awareness about genetic diversities, and their consequences in these diseases, have greatly expanded. Modern solutions are focused on mobilizing and impacting a patient’s immune system. Strategies to stimulate the immune system, to prime an antitumor response, are of intense interest. Amid those types of therapies are chimeric antigen receptor T (CAR-T) cells, bispecific antibodies, and antibody–drug conjugates (ADC), which have already been approved in the treatment of acute lymphoblastic leukemia (ALL)/acute myeloid leukemia (AML). In addition, immune checkpoint inhibitors (ICIs), the pattern recognition receptors (PRRs), i.e., NOD-like receptors (NLRs), Toll-like receptors (TLRs), and several kinds of therapy antibodies are well on their way to showing significant benefits for patients with these diseases. This review summarizes the current knowledge of modern methods used in selected pediatric malignancies and presents therapies that may hold promise for the future.

miR-10c Facilitates White Spot Syndrome Virus Infection by Targeting Toll3 in Litopenaeus vannemei

Toll-like receptors (TLRs) are canonical cell membrane receptors functioning to recognize pathogens and transduce signals to activate immune responses. It has been known that Toll3 in Pacific white shrimp Litopenaeus vannamei (LvToll3) plays a critical role in antiviral immunity by inducing the transcription of interferon regulatory factor (IRF), which mediates a signaling axis that is similar to the interferon system of vertebrates. However, the regulatory mechanism of the Toll3-IRF signaling is still unclear. In this study, a novel microRNA (miRNA) of miR-10 family, temporarily named as miR-10c, was identified from L. vannamei. miR-10c may play a nonnegligible regulatory role in shrimp immune responses since it was constitutively expressed in all detected tissues and transcriptionally induced by immune stimulation. Functional analysis validated that miR-10c could target LvToll3 to inhibit its expression, through which miR-10c blocked the nuclear translocation of IRF and facilitated white spot syndrome virus (WSSV) infection. To our knowledge, the present study revealed the first report of a Toll targeted by miRNA in crustaceans and provided a solid evidence base for supporting the role of LvToll3 in antiviral defense by activating IRF signaling in L. vannamei. Identification of the miR-10c/Toll3/IRF regulatory axis in shrimp provides new insights into the participation of miRNA in the regulation of immune responses and contributes to in-depth understanding of the mechanisms of Toll-induced immune responses in L. vannamei.

Acute Exposure to the Food-Borne Pathogen Listeria monocytogenes Does Not Induce α-Synuclein Pathology in the Colonic ENS of Nonhuman Primates

INTRODUCTION

Gastrointestinal (GI) inflammation elicited by environmental factors is proposed to trigger Parkinson's disease (PD) by stimulating accumulation of pathological α-synuclein (α-syn) in the enteric nervous system (ENS), which then propagates to the central nervous system via the vagus nerve. The goal of this study was to model, in nonhuman primates, an acute exposure to a common food-borne pathogen in order to assess whether the related acute GI inflammation could initiate persistent α-syn pathology in the ENS, ultimately leading to PD.

METHODS

Adult female cynomolgus macaques were inoculated by oral gavage with 1×108 colony-forming units (CFUs) Listeria monocytogenes (LM, n=10) or vehicle (mock, n=3) and euthanized 2 weeks later. Evaluations included clinical monitoring, blood and fecal shedding of LM, and postmortem pathological analysis of colonic and cecal tissues.

RESULTS

LM inoculation of healthy adult cynomolgus macaques induced minimal to mild clinical signs of infection; LM shedding in feces was not seen in any of the animals nor was bacteremia detected. Colitis varied from none to moderate in LM-treated subjects and none to minimal in mock-treated subjects. Expression of inflammatory markers (HLA-DR, CD3, CD20), oxidative stress (8-OHDG), α-syn, and phosphorylated-α-syn in the enteric ganglia was not significantly different between treatment groups.

DISCUSSION

Our results demonstrate that cynomolgus macaques orally inoculated with LM present with a clinical response that resembles human LM exposure. They also suggest that acute exposure to food-borne pathogens is not sufficient to induce significant and persistent α-syn changes in healthy adult female subjects. Based on the results of this limited experimental setting, we propose that, if LM has a role in PD pathology, other underlying factors or conditions, such as male sex, inflammatory bowel disease, exposure to toxins, dysbiosis, and/or aging, are needed to be present.

Innate Immunity Modulating Impurities and the Immunotoxicity of Nanobiotechnology-Based Drug Products

Innate immunity can be triggered by the presence of microbial antigens and other contaminants inadvertently introduced during the manufacture and purification of bionanopharmaceutical products. Activation of these innate immune responses, including cytokine secretion, complement, and immune cell activation, can result in unexpected and undesirable host immune responses. These innate modulators can also potentially stimulate the activation of adaptive immune responses, including the formation of anti-drug antibodies which can impact drug effectiveness. To prevent induction of these adverse responses, it is important to detect and quantify levels of these innate immunity modulating impurities (IIMIs) that may be present in drug products. However, while it is universally agreed that removal of IIMIs from drug products is crucial for patient safety and to prevent long-term immunogenicity, there is no single assay capable of directly detecting all potential IIMIs or indirectly quantifying downstream biomarkers. Additionally, there is a lack of agreement as to which of the many analytical assays currently employed should be standardized for general IIMI screening. Herein, we review the available literature to highlight cellular and molecular mechanisms underlying IIMI-mediated inflammation and its relevance to the safety and efficacy of pharmaceutical products. We further discuss methodologies used for direct and indirect IIMI identification and quantification.

The journey of SARS-CoV-2 in human hosts: a review of immune responses, immunosuppression, and their consequences

Coronavirus disease 2019 (COVID-19) is a highly infectious viral disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Laboratory findings from a significant number of patients with COVID-19 indicate the occurrence of leukocytopenia, specifically lymphocytopenia. Moreover, infected patients can experience contrasting outcomes depending on lymphocytopenia status. Patients with resolved lymphocytopenia are more likely to recover, whereas critically ill patients with signs of unresolved lymphocytopenia develop severe complications, sometimes culminating in death. Why immunodepression manifests in patients with COVID-19 remains unclear. Therefore, the evaluation of clinical symptoms and laboratory findings from infected patients is critical for understanding the disease course and its consequences. In this review, we take a logical approach to unravel the reasons for immunodepression in patients with COVID-19. Following the footprints of the virus within host tissues, from entry to exit, we extrapolate the mechanisms underlying the phenomenon of immunodepression.

Salmonella Typhimurium and inflammation: a pathogen-centric affair

Microbial infections are controlled by host inflammatory responses that are initiated by innate immune receptors after recognition of conserved microbial products. As inflammation can also lead to disease, tissues that are exposed to microbial products such as the intestinal epithelium are subject to stringent regulatory mechanisms to prevent indiscriminate signalling through innate immune receptors. The enteric pathogen Salmonella enterica subsp. enterica serovar Typhimurium, which requires intestinal inflammation to sustain its replication in the intestinal tract, uses effector proteins of its type III secretion systems to trigger an inflammatory response without the engagement of innate immune receptors. Furthermore, S. Typhimurium uses a different set of effectors to restrict the inflammatory response to preserve host homeostasis. The S. Typhimurium-host interface is a remarkable example of the unique balance that emerges from the co-evolution of a pathogen and its host.

Inflammation: improving understanding to prevent or ameliorate kidney diseases

Inflammatory processes are believed to play an important role in immune response to maintain tissue homeostasis by activating cellular signaling pathways and releasing inflammatory mediators in the injured tissue. Although acute inflammation can be considered protective, an uncontrolled inflammation may evolve to tissue damage, leading to chronic inflammatory diseases. Inflammation can be considered the major factor involved in the pathological progression of acute and chronic kidney diseases. Functional characteristics of this organ increase its vulnerability to developing various forms of injuries, including acute kidney injury (AKI) and chronic kidney disease (CKD). In view of translational research, several discoveries should be considered regarding the pathogenesis of the inflammatory process, which results in the validation of biomarkers for early detection of kidney diseases. Biomarkers enable the identification of proinflammatory mediators in kidney affections, based on laboratory research applied to clinical practice. Some inflammatory molecules can be useful biomarkers for the detection and diagnosis of kidney diseases, such as neutrophil gelatinase-associated lipocalin, kidney injury molecule-1 and interleukin 18.

The circular RNA circBCL2L1 regulates innate immune responses via microRNA-mediated downregulation of TRAF6 in teleost fish

Growing numbers of studies have shown that circular RNAs (circRNAs) can function as regulatory factors to regulate the innate immune response, cell proliferation, cell migration, and other important processes in mammals. However, the function and regulatory mechanism of circRNAs in lower vertebrates are still unclear. Here, we discovered a novel circRNA derived from the gene encoding Bcl-2-like protein 1 (BCL2L1) gene, named circBCL2L1, which was related to the innate immune responses in teleost fish. Results indicated that circBCL2L1 played essential roles in host antiviral immunity and antibacterial immunity. Our study also identified a microRNA, miR-30c-3-3p, which could inhibit the innate immune response by targeting inflammatory mediator TRAF6. And TRAF6 is a key signal transduction factor in innate immune response mediated by TLRs. Moreover, we also found that the antiviral and antibacterial effects inhibited by miR-30c-3-3p could be reversed with the expression of circBCL2L1. Our data revealed that circBCL2L1 functioned as a competing endogenous RNA (ceRNA) of TRAF6 by competing for binding with miR-30c-3-3p, leading to activation of the NF-κB/IRF3 inflammatory pathway and then enhancing the innate immune responses. Our results suggest that circRNAs can play an important role in the innate immune response of teleost fish.

Effect of Papaya Leaves (<i>Carica papaya</i> L.) Extract on Immune Response (TLR-7, TLR-9) and Inflammation (COX-2) in Rats Induces DMBA (7,12-Dimethylbenz[a]antrasen)

BACKGROUND AND OBJECTIVE

TLR is known to regulate the immune system in cancer. TLR-7 and TLR-9 can enhance the antitumor immune system in many types of solid tumors. Cyclooxygenase-2 (COX-2) is a biomarker of inflammation. This study aimed to investigate the effect of papaya leaves extract on immune response (TLR 7, TLR 9) and inflammation (COX-2) in rats induced DMBA.

MATERIALS AND METHODS

This experimental study used Sprague dawley female rats of age more less 50 days. Rats were divided into 4 groups: Negative Control (NC), Positive Control (PC), Cancer Drug Doxorubicin (DOXO) and Papaya Leaves Extract (PLE). The study was conducted for 13 weeks. DMBA induction performed for 5 weeks with administration of 2 times per week.

RESULTS

the expression of TLR-7 of PLE and DOXO was higher than PC groups significantly different (p<0.05). The expression of TLR-9 of PLE was higher than NC, PC and DOXO groups but not significantly different (p>0.05) while the expression of COX-2 of PLE and DOXO groups was lower than NC and PC groups but not significantly different (p>0.05).

CONCLUSION

It can be concluded that papaya leaves extract can improve the immune system and reduce inflammation. It shows that papaya leaves extract has potent as anti-cancer.

IFP35 family proteins promote neuroinflammation and multiple sclerosis

Excessive activation of T cells and microglia represents a hallmark of the pathogenesis of human multiple sclerosis (MS). However, the regulatory molecules overactivating these immune cells remain to be identified. Previously, we reported that extracellular IFP35 family proteins, including IFP35 and NMI, activated macrophages as proinflammatory molecules in the periphery. Here, we investigated their functions in the process of neuroinflammation both in the central nervous system (CNS) and the periphery. Our analysis of clinical transcriptomic data showed that expression of IFP35 family proteins was up-regulated in patients with MS. Additional in vitro studies demonstrated that IFP35 and NMI were released by multiple cells. IFP35 and NMI subsequently triggered nuclear factor kappa B-dependent activation of microglia via the TLR4 pathway. Importantly, we showed that both IFP35 and NMI activated dendritic cells and promoted naïve T cell differentiation into Th1 and Th17 cells. Nmi-/- , Ifp35-/- , or administration of neutralizing antibodies against IFP35 alleviated the immune cells' infiltration and demyelination in the CNS, thus reducing the severity of experimental autoimmune encephalomyelitis. Together, our findings reveal a hitherto unknown mechanism by which IFP35 family proteins facilitate overactivation of both T cells and microglia and propose avenues to study the pathogenesis of MS.

Photothermal therapy combined with neoantigen cancer vaccination for effective immunotherapy against large established tumors and distant metastasis

Photothermal therapy (PTT) and neoantigen cancer vaccine each offers minimally invasive and highly specific cancer therapy; however, they are not effective against large established tumors due to physical and biological barriers that attenuate thermal ablation and abolish anti-tumor immunity. Here, we designed and performed comparative study using small (~ 50 mm3) and large (> 100 mm3) tumors to examine how tumor size affects the therapeutic efficiency of PTT and neoantigen cancer vaccine. We show that spiky gold nanoparticle (SGNP)-based PTT and synergistic dual adjuvant-based neoantigen cancer vaccine can efficiently regress small tumors as a single agent, but not large tumors due to limited internal heating and immunosuppressive tumor microenvironment (TME). We report that PTT sensitizes tumors to neoantigen cancer vaccination by destroying and compromising the TME via thermally induced cellular and molecular damage, while neoantigen cancer vaccine reverts local immune suppression induced by PTT and shapes residual TME in favor of anti-tumor immunity. The combination therapy efficiently eradicated large local tumors and also exerted strong abscopal effect against pre-established distant tumors with robust systemic anti-tumor immunity. Thus, PTT combined with neoantigen cancer vaccine is a promising nano-immunotherapy for personalized therapy of advanced cancer.