Comprehensive network map of interferon gamma signaling

Exploring the impact of interferon-gamma single nucleotide polymorphisms on HTLV-1 infection: Unraveling genetic influences in viral pathogenesis

Human T-lymphotropic virus-1 (HTLV-1) induces neoplastic adult T-cell leukemia/lymphoma (ATLL) and neurological HTLV-1 associated myelopathy (HAM) in approximately 3 %-5 % of infected individuals. The precise factors that facilitate disease manifestation are still unknown; interaction between the virus and the host's immune response is key. Cytokines regulates physiological activities and their dysregulation may initiate the pathogenesis of various malignant and infectious diseases. Genetic variations, particularly polymorphisms in gene regulatory regions, lead to varying cytokine production patterns. Interferon-gamma (IFN-γ), a key cytokine in HTLV-1 infection, is a signature cytokine for T-helper 1 (Th1) cells that interferes with viral replication and enhances innate and adaptive immune responses during viral infections. The IFNG gene possesses several single nucleotide polymorphisms (SNPs), among which the + 874 A/T SNP has been widely studied for its functional role in HTLV-1 infection. The purpose of this review was to provide insight into the impact of IFNG SNPs on HTLV-1 Infection.

A review on multiple sclerosis: Unravelling the complexities of pathogenesis, progression, mechanisms and therapeutic innovations

Multiple sclerosis (MS) is a chronic, inflammatory demyelinating disorder of the central nervous system (CNS) targeting myelinated axons. Pathogenesis of MS entails an intricate genetic, environmental, and immunological interaction. Dysregulation of immune response i.e. autoreactive T & B-Cells and macrophage infiltration into the CNS leads to inflammation, demyelination, and neurodegeneration. Disease progression of MS varies among individuals transitioning from one form of relapsing-remitting to secondary progressive MS (SPMS). Research advances have unfolded various molecular targets involved in MS from oxidative stress to blood-brain barrier (BBB) disruption. Different pathways are being targeted so far such as inflammatory and cytokine signaling pathways to overcome disease progression. Therapeutic innovations have significantly transformed the management of MS, especially the use of disease-modifying therapies (DMTs) to reduce relapse rates and control disease progression. Advancements in research, neuroprotective strategies, and remyelination strategies hold promising results in reversing CNS damage. Various mice models are being adopted for testing new entities in MS research.

A Mutant of Africa Swine Fever Virus Protein p72 Enhances Antibody Production and Regulates the Production of Cytokines

African swine fever virus (ASFV) is a severe threat to the global pig industry, and domestic pigs mostly develop severe clinical manifestations upon viral invasion. Currently, there is no available vaccine against ASFV. Its capsid structural protein p72 is one of the immuno-dominant proteins. In this study, we unexpectedly obtained a p72 mutant protein (p72∆377-428) which deleted the aa 377-428 within p72 and had stable and high expression in E. coli. Using SWISS-MODEL 1.0 software, the prediction showed that p72∆377-428 was quite distinct from the wild-type p72 protein in structure. p72∆377-428 induced stronger antibody production in mice on day 42 and 56 post immunization and could recognize ASFV-infected swine sera. p72∆377-428 reduced IFN-γ production in the splenocytes from p72∆377-428-immunized mice and p72∆377-428-treated swine macrophages compared to p72. p72∆377-428 also decreased the production of pro-inflammatory cytokine genes, including IL-1β, IL-6, and IL-12, compared to p72 in mice. Further, we found that p72∆377-428 reduced the induction of pro-inflammatory cytokine genes by inhibiting AKT phosphorylation and HIF1α expression. Taken together, these findings have implications for immunological function and the corresponding mechanism of ASFV p72, and our study indicates that p72∆377-428 could serve as a novel candidate for ASFV vaccines and diagnostic reagents.

In silico assessment of CAR macrophages activity against SARS-CoV-2 infection

Macrophage engineering with chimeric antigen receptor is a promising technique first applied to the treatment of tumours and recently suggested as a possible immunotherapeutic route against the COVID-19 disease. Four immunotherapies based on engineered macrophages have been tested in vitro revealing promising, with one of them acting without increasing the cytokines level. We present a mathematical model aimed at the evaluation of both the SARS-CoV-2 virions dynamics and the cytokines production induced, while such newly developed constructs interact with the immune system once administered. The importance of the study lies both in monitoring the dynamics of the infection and in evaluating the cytokine production, since clinical studies show that in critical COVID-19 patients an abnormal cytokines production occurs, a concern to be accounted for in designing appropriate therapeutic strategies. The mathematical model was built in the context of the continuum approach of the mass conservation, while the numerical simulations have been performed introducing parameters deduced from the experiments, using the finite element method. The model simulations allow to analyse and to compare the immune mechanisms underlying the virus dynamics, deepening the investigation for two selected immunotherapies, suggesting that a synergistic work of involved cytokines with phagocytic activity of macrophages occurs. The best SARS-CoV-2 clearance relies not only on the phagocytic capacity of the engineered macrophages, but also on the production of T-lymphocytes, pro- and anti-inflammatory cytokines which in the two cases examined in depth can decrease by 99.7 %, 99.6 % and 69 % respectively, passing from the most effective immunotherapy to the least effective one. This study is the first mathematical model that analyses the dynamics of macrophages engineered to fight the COVID-19, and paves the way for their possible exploitation against such a challenging disease, going beyond existing models involving other immune cells.

Inflammatory pathways of Toxoplasmagondii infection in pregnancy

Toxoplasma gondii (T. gondii), an obligate intracellular parasite, is considered as an opportunistic infection and causes toxoplasmosis in humans and animals. Congenital toxoplasmosis can influence pregnancy and cause mild to severe consequences for the fetal and neonatal. During early T. gondii infection, neutrophils as the most abundant white blood cells provide a front line of defense mechanism against infection. The activated dendritic cells are then responsible for initiating an inflammatory response via T-helper 1 (Th1) cells. As part of its robust immune response, the infected host cells produce interferon (IFN-γ). IFN-γ inhibits T. gondii replication and promotes its transformation from an active form to tissue cysts. Although anti- T. gondii antibodies play an important role in infection control, T-helper 2 (Th2) immune response, can facilitate the growth and proliferation of T. gondii in the host cell. In pregnant women infected with T. gondii, the expression of cytokines may vary and in response diverse outcomes are expected. Cytokine profiles serve as valuable indicators for estimating the patho-immunological effects of T. gondii infection. This demonstrates the intricate relationship between pro-inflammatory and anti-inflammatory cytokines, as well as their influence on the various pregnancy outcomes in T. gondii infection.

Role of immune cells in mediating the effect of gut microbiota on Hashimoto's thyroiditis: a 2-sample Mendelian randomization study

Purpose

Hashimoto's thyroiditis (HT) is one of the most commonly encountered types of autoimmune thyroid disorders (AITDs), influenced by environmental factors, genetics, and the immune system. Previous research has shown a correlation between gut microbiota and HT, as well as the involvement of immune cells in its onset and progression. We aimed to investigate whether immune cells act as intermediaries in the causal relationship between gut microbiota and HT.

Methods

In this study, we conducted bidirectional two-sample Mendelian randomization (MR) analyses to explore the relationship between gut microbiota and HT using data from genome-wide association studies (GWAS) and the MiBioGen study. Subsequently, MR analyses were performed to investigate the interactions between 731 immune cells and gut microbiota. Additionally, an MR analysis was performed to examine the association between HT and these 731 immune cells, using a GWAS dataset that included 3,757 European subjects. This approach provided insights into the impact of 22 million genetic variants on 731 immune cell signatures.

Results

There was a causal relationship between the increase in the number of 15 gut microbiota and HT. We observed that the genus Akkermansia, family Alcaligenaceae, family Desulfovibrionaceae, family Verrucomicrobiaceae, class Verrucomicrobiae, order Verrucomicrobiales, phylum Verrucomicrobia, class Alphaproteobacteria, order Desulfovibrionales, genus Ruminococcus torques group, genus Butyrivibrio, and genus Coprococcus3 were negatively correlated with HT. In addition, the genus Intestinimonas, genus Turicibacter, and genus Anaerostipes were positively correlated with HT. We identified EM CD4 + T cells as a mediator between the gut microbiota and HT.

Conclusion

In conclusion, we presented causal associations between the EM CD4 + T cell-mediated gut microbiota and HT, as inferred from the MR findings derived from extensive aggregated GWAS data. Our research offers guidance and direction for treating and preventing HT.

Oligodendrocytes in central nervous system diseases: the effect of cytokine regulation

Cytokines including tumor necrosis factor, interleukins, interferons, and chemokines are abundantly produced in various diseases. As pleiotropic factors, cytokines are involved in nearly every aspect of cellular functions such as migration, survival, proliferation, and differentiation. Oligodendrocytes are the myelin-forming cells in the central nervous system and play critical roles in the conduction of action potentials, supply of metabolic components for axons, and other functions. Emerging evidence suggests that both oligodendrocytes and oligodendrocyte precursor cells are vulnerable to cytokines released under pathological conditions. This review mainly summarizes the effects of cytokines on oligodendrocyte lineage cells in central nervous system diseases. A comprehensive understanding of the effects of cytokines on oligodendrocyte lineage cells contributes to our understanding of central nervous system diseases and offers insights into treatment strategies.

Potential Application of Plant-Derived Compounds in Multiple Sclerosis Management

Multiple sclerosis (MS) is a chronic autoimmune disorder characterized by inflammation, demyelination, and neurodegeneration, resulting in significant disability and reduced quality of life. Current therapeutic strategies primarily target immune dysregulation, but limitations in efficacy and tolerability highlight the need for alternative treatments. Plant-derived compounds, including alkaloids, phenylpropanoids, and terpenoids, have demonstrated anti-inflammatory effects in both preclinical and clinical studies. By modulating immune responses and promoting neuroregeneration, these compounds offer potential as novel adjunctive therapies for MS. This review provides insights into the molecular and cellular basis of MS pathogenesis, emphasizing the role of inflammation in disease progression. It critically evaluates emerging evidence supporting the use of plant-derived compounds to attenuate inflammation and MS symptomology. In addition, we provide a comprehensive source of information detailing the known mechanisms of action and assessing the clinical potential of plant-derived compounds in the context of MS pathogenesis, with a focus on their anti-inflammatory and neuroprotective properties.

Gut Microbiota and Cytokine Profile in Cirrhosis

Background and Aims

Gut dysbiosis and abnormal cytokine profiles are common in cirrhosis. This study aimed to evaluate the correlations between them.

Methods

In the blood plasma of cirrhosis patients and controls, 27 cytokines were examined using a multiplex assay. The plasma levels of nitrites (stable metabolites of the endothelial dysfunction biomarker nitric oxide) and lipopolysaccharide (LPS) were examined. The fecal microbiota was assessed by 16S rRNA gene sequencing.

Results

Levels of IL-1b, IL-2, IL-6, IL-13, IP-10, IFN-g, TNF-a, LPS, and nitrites were higher in cirrhosis patients than in controls, while levels of IL-4, IL-7, and PDGF-BB were lower. The LPS level was directly correlated with the levels of IL-1b, IL1-Ra, IL-9, IL-17, PDGF-BB, IL-6, TNF-a, and nitrites. The nitrite level was significantly directly correlated with the levels of TNF-a, GM-CSF, IL-17, and IL-12, and inversely correlated with the IL-7 level. TNF-a levels were directly correlated with ascites severity and the abundance of Negativicutes, Enterobacteriaceae, Veillonellaceae, and Klebsiella, while inversely correlated with the abundance of Firmicutes, Clostridia, and Subdoligranulum. IFN-g levels were directly correlated with the abundance of Bacteroidaceae, Lactobacillaceae, Bacteroides, and Megasphaera, and inversely correlated with the abundance of Verrucomicrobiota, Akkermansiaceae, Coriobacteriaceae, Akkermansia, Collinsella, and Gemella. IL-1b levels were directly correlated with the abundance of Comamonadaceae and Enterobacteriaceae and inversely correlated with the abundance of Marinifilaceae and Dialister. IL-6 levels were directly correlated with the abundance of Enterobacteriaceae, hepatic encephalopathy, and ascites severity, and inversely correlated with the abundance of Peptostreptococcaceae, Streptococcaceae, and Streptococcus.

Conclusions

The abundance of harmful gut microbiota taxa and endotoxinemia directly correlates with the levels of proinflammatory cytokines.

Immunological correlates of protection mediated by a whole organism, Cryptococcus neoformans, vaccine deficient in chitosan

The global burden of infections due to the pathogenic fungus Cryptococcus is substantial in persons with low CD4+ T-cell counts. Previously, we deleted three chitin deacetylase genes from Cryptococcus neoformans to create a chitosan-deficient, avirulent strain, designated as cda1∆2∆3∆, which, when used as a vaccine, protected mice from challenge with virulent C. neoformans strain KN99. Here, we explored the immunological basis for protection. Vaccine-mediated protection was maintained in mice lacking B cells or CD8+ T cells. In contrast, protection was lost in mice lacking α/β T cells or CD4+ T cells. Moreover, CD4+ T cells from vaccinated mice conferred protection upon adoptive transfer to naive mice. Importantly, while monoclonal antibody-mediated depletion of CD4+ T cells just prior to vaccination resulted in complete loss of protection, significant protection was retained in mice depleted of CD4+ T cells after vaccination but prior to challenge. Vaccine-mediated protection was lost in mice genetically deficient in interferon-γ (IFNγ), tumor necrosis factor alpha (TNFα), or interleukin (IL)-23p19. A robust influx of leukocytes and IFNγ- and TNFα-expressing CD4+ T cells was seen in the lungs of vaccinated and challenged mice. Finally, a higher level of IFNγ production by lung cells stimulated ex vivo correlated with lower fungal burden in the lungs. Thus, while B cells and CD8+ T cells are dispensable, IFNγ and CD4+ T cells have overlapping roles in generating protective immunity prior to cda1∆2∆3∆ vaccination. However, once vaccinated, protection becomes less dependent on CD4+ T cells, suggesting a strategy for vaccinating HIV+ persons prior to loss of CD4+ T cells.

IMPORTANCE

The fungus Cryptococcus neoformans is responsible for >100,000 deaths annually, mostly in persons with impaired CD4+ T-cell function such as AIDS. There are no approved human vaccines. We previously created a genetically engineered avirulent strain of C. neoformans, designated as cda1∆2∆3∆. When used as a vaccine, cda1∆2∆3∆ protects mice against a subsequent challenge with a virulent C. neoformans strain. Here, we defined components of the immune system responsible for vaccine-mediated protection. We found that while B cells and CD8+ T cells were dispensible, protection was lost in mice genetically deficient in CD4+ T cells and the cytokines IFNγ, TNFα, or IL-23. A robust influx of cytokine-producing CD4+ T cells was seen in the lungs of vaccinated mice following infection. Importantly, protection was retained in mice depleted of CD4+ T cells following vaccination, suggesting a strategy to protect persons who are at risk of future CD4+ T-cell dysfunction.

In-silico discovery of common molecular signatures for which SARS-CoV-2 infections and lung diseases stimulate each other, and drug repurposing

COVID-19 caused by SARS-CoV-2 is a global health issue. It is yet a severe risk factor to the patients, who are also suffering from one or more chronic diseases including different lung diseases. In this study, we explored common molecular signatures for which SARS-CoV-2 infections and different lung diseases stimulate each other, and associated candidate drug molecules. We identified both SARS-CoV-2 infections and different lung diseases (Asthma, Tuberculosis, Cystic Fibrosis, Pneumonia, Emphysema, Bronchitis, IPF, ILD, and COPD) causing top-ranked 11 shared genes (STAT1, TLR4, CXCL10, CCL2, JUN, DDX58, IRF7, ICAM1, MX2, IRF9 and ISG15) as the hub of the shared differentially expressed genes (hub-sDEGs). The gene ontology (GO) and pathway enrichment analyses of hub-sDEGs revealed some crucial common pathogenetic processes of SARS-CoV-2 infections and different lung diseases. The regulatory network analysis of hub-sDEGs detected top-ranked 6 TFs proteins and 6 micro RNAs as the key transcriptional and post-transcriptional regulatory factors of hub-sDEGs, respectively. Then we proposed hub-sDEGs guided top-ranked three repurposable drug molecules (Entrectinib, Imatinib, and Nilotinib), for the treatment against COVID-19 with different lung diseases. This recommendation is based on the results obtained from molecular docking analysis using the AutoDock Vina and GLIDE module of Schrödinger. The selected drug molecules were optimized through density functional theory (DFT) and observing their good chemical stability. Finally, we explored the binding stability of the highest-ranked receptor protein RELA with top-ordered three drugs (Entrectinib, Imatinib, and Nilotinib) through 100 ns molecular dynamic (MD) simulations with YASARA and Desmond module of Schrödinger and observed their consistent performance. Therefore, the findings of this study might be useful resources for the diagnosis and therapies of COVID-19 patients who are also suffering from one or more lung diseases.

Interleukin 27, Similar to Interferons, Modulates Gene Expression of Tripartite Motif (TRIM) Family Members and Interferes with Mayaro Virus Replication in Human Macrophages

BACKGROUND

The Tripartite motif (TRIM) family includes more than 80 distinct human genes. Their function has been implicated in regulating important cellular processes, including intracellular signaling, transcription, autophagy, and innate immunity. During viral infections, macrophages are key components of innate immunity that produce interferons (IFNs) and IL27. We recently published that IL27 and IFNs induce transcriptional changes in various genes, including those involved in JAK-STAT signaling. Furthermore, IL27 and IFNs share proinflammatory and antiviral pathways in monocyte-derived macrophages (MDMs), resulting in both common and unique expression of inflammatory factors and IFN-stimulated genes (ISGs) encoding antiviral proteins. Interestingly, many TRIM proteins have been recognized as ISGs in recent years. Although it is already very well described that TRIM expression is induced by IFNs, it is not fully understood whether TRIM genes are induced in macrophages by IL27. Therefore, in this study, we examined the effect of stimulation with IL27 and type I, II, and III IFNs on the mRNA expression profiles of TRIM genes in MDMs.

METHODS

We used bulk RNA-seq to examine the TRIM expression profile of MDMs treated with IFNs or IL27. Initially, we characterized the expression patterns of different TRIM subfamilies using a heatmap. Subsequently, a volcano plot was employed to identify commonly differentially expressed TRIM genes. Additionally, we conducted gene ontology analysis with ClueGO to explore the biological processes of the regulated TRIMs, created a gene-gene interaction network using GeneMANIA, and examined protein-protein interactions with the STRING database. Finally, RNA-seq data was validated using RT-qPCR. Furthermore, the effect of IL27 on Mayaro virus replication was also evaluated.

RESULTS

We found that IL27, similar to IFNs, upregulates several TRIM genes' expression in human macrophages. Specifically, we identified three common TRIM genes (TRIM19, 21, and 22) induced by IL27 and all types of human IFNs. Additionally, we performed the first report of transcriptional regulation of TRIM19, 21, 22, and 69 genes in response to IL27. The TRIMs involved a broad range of biological processes, including defense response to viruses, viral life cycle regulation, and negative regulation of viral processes. In addition, we observed a decrease in Mayaro virus replication in MDMs previously treated with IL27.

CONCLUSIONS

Our results show that IL27, like IFNs, modulates the transcriptional expression of different TRIM-family members involved in the induction of innate immunity and an antiviral response. In addition, the functional analysis demonstrated that, like IFN, IL27 reduced Mayaro virus replication in MDMs. This implies that IL27 and IFNs share many similarities at a functional level. Moreover, identifying distinct TRIM groups and their differential expressions in response to IL27 provides new insights into the regulatory mechanisms underlying the antiviral response in human macrophages.

Immunological correlates of protection mediated by a whole organism Cryptococcus neoformans vaccine deficient in chitosan

The global burden of infections due to the pathogenic fungus Cryptococcus is substantial in persons with low CD4 + T cell counts. Previously, we deleted three chitin deacetylase genes from C. neoformans to create a chitosan-deficient, avirulent strain, designated cda1Δ2Δ3Δ which, when used as a vaccine, protected mice from challenge with virulent C. neoformans strain KN99. Here, we explored the immunological basis for protection. Vaccine-mediated protection was maintained in mice lacking B cells or CD8 + T cells. In contrast, protection was lost in mice lacking α/β T cells or CD4 + T cells. Moreover, CD4 + T cells from vaccinated mice conferred protection upon adoptive transfer to naive mice. Importantly, while monoclonal antibody-mediated depletion of CD4 + T cells just prior to vaccination resulted in complete loss of protection, significant protection was retained in mice depleted of CD4 + T cells after vaccination, but prior to challenge. Vaccine-mediated protection was lost in mice genetically deficient in IFNγ, TNFα, or IL-23p19. A robust influx of leukocytes and IFNγ- and TNFα-expressing CD4 + T cells was seen in the lungs of vaccinated and challenged mice. Finally, a higher level of IFNγ production by lung cells stimulated ex vivo correlated with lower fungal burden in the lungs. Thus, while B cells and CD8 + T cells are dispensable, IFNγ and CD4 + T cells have overlapping roles in generating protective immunity prior to cda1Δ2Δ3Δ vaccination. However, once vaccinated, protection becomes less dependent on CD4 + T cells, suggesting a strategy for vaccinating HIV + persons prior to loss of CD4 + T cells.

Importance

The fungus Cryptococcus neoformans is responsible for >100,000 deaths annually, mostly in persons with impaired CD4 + T cell function such as AIDS. There are no approved human vaccines. We previously created a genetically engineered avirulent strain of C. neoformans , designated cda1Δ2Δ3Δ . When used as a vaccine, cda1Δ2Δ3Δ protects mice against a subsequent challenge with a virulent C. neoformans strain. Here, we defined components of the immune system responsible for vaccine-mediated protection. We found that while B cells and CD8 + T cells were dispensible, protection was lost in mice genetically deficient in CD4 + T cells, and the cytokines IFNγ, TNFα, or IL-23. A robust influx of cytokine-producing CD4 + T cells was seen in the lungs of vaccinated mice following infection. Importantly, protection was retained in mice depleted of CD4 + T cells following vaccination, suggesting a strategy to protect persons who are at risk for future CD4 + T cell dysfunction.

Therapeutic role of interferon-γ in experimental autoimmune encephalomyelitis is mediated through a tolerogenic subset of splenic CD11b+ myeloid cells

Cumulative evidence has established that Interferon (IFN)-γ has both pathogenic and protective roles in Multiple Sclerosis and the animal model, Experimental Autoimmune Encephalomyelitis (EAE). However, the underlying mechanisms to the beneficial effects of IFN-γ are not well understood. In this study, we found that IFN-γ exerts therapeutic effects on chronic, relapsing-remitting, and chronic progressive EAE models. The frequency of regulatory T (Treg) cells in spinal cords from chronic EAE mice treated with IFN-γ was significantly increased with no effect on Th1 and Th17 cells. Consistently, depletion of FOXP3-expressing cells blocked the protective effects of IFN-γ, indicating that the therapeutic effect of IFN-γ depends on the presence of Treg cells. However, IFN-γ did not trigger direct in vitro differentiation of Treg cells. In vivo administration of blocking antibodies against either interleukin (IL)-10, transforming growth factor (TGF)-β or program death (PD)-1, revealed that the protective effects of IFN-γ in EAE were also dependent on TGF-β and PD-1, but not on IL-10, suggesting that IFN-γ might have an indirect role on Treg cells acting through antigen-presenting cells. Indeed, IFN-γ treatment increased the frequency of a subset of splenic CD11b+ myeloid cells expressing TGF-β-Latency Associated Peptide (LAP) and program death ligand 1 (PD-L1) in a signal transducer and activator of transcription (STAT)-1-dependent manner. Furthermore, splenic CD11b+ cells from EAE mice preconditioned in vitro with IFN-γ and myelin oligodendrocyte glycoprotein (MOG) peptide exhibited a tolerogenic phenotype with the capability to induce conversion of naïve CD4+ T cells mediated by secretion of TGF-β. Remarkably, adoptive transfer of splenic CD11b+ cells from IFN-γ-treated EAE mice into untreated recipient mice ameliorated clinical symptoms of EAE and limited central nervous system infiltration of mononuclear cells and effector helper T cells. These results reveal a novel cellular and molecular mechanism whereby IFN-γ promotes beneficial effects in EAE by endowing splenic CD11b+ myeloid cells with tolerogenic and therapeutic activities.

Regulatory mechanisms of PD-1/PD-L1 in cancers

Immune evasion contributes to cancer growth and progression. Cancer cells have the ability to activate different immune checkpoint pathways that harbor immunosuppressive functions. The programmed death protein 1 (PD-1) and programmed cell death ligands (PD-Ls) are considered to be the major immune checkpoint molecules. The interaction of PD-1 and PD-L1 negatively regulates adaptive immune response mainly by inhibiting the activity of effector T cells while enhancing the function of immunosuppressive regulatory T cells (Tregs), largely contributing to the maintenance of immune homeostasis that prevents dysregulated immunity and harmful immune responses. However, cancer cells exploit the PD-1/PD-L1 axis to cause immune escape in cancer development and progression. Blockade of PD-1/PD-L1 by neutralizing antibodies restores T cells activity and enhances anti-tumor immunity, achieving remarkable success in cancer therapy. Therefore, the regulatory mechanisms of PD-1/PD-L1 in cancers have attracted an increasing attention. This article aims to provide a comprehensive review of the roles of the PD-1/PD-L1 signaling in human autoimmune diseases and cancers. We summarize all aspects of regulatory mechanisms underlying the expression and activity of PD-1 and PD-L1 in cancers, including genetic, epigenetic, post-transcriptional and post-translational regulatory mechanisms. In addition, we further summarize the progress in clinical research on the antitumor effects of targeting PD-1/PD-L1 antibodies alone and in combination with other therapeutic approaches, providing new strategies for finding new tumor markers and developing combined therapeutic approaches.

Host Immune Response Modulation in Avian Coronavirus Infection: Tracheal Transcriptome Profiling In Vitro and In Vivo

Infectious bronchitis virus (IBV) is a highly contagious Gammacoronavirus causing moderate to severe respiratory infection in chickens. Understanding the initial antiviral response in the respiratory mucosa is crucial for controlling viral spread. We aimed to characterize the impact of IBV Delmarva (DMV)/1639 and IBV Massachusetts (Mass) 41 at the primary site of infection, namely, in chicken tracheal epithelial cells (cTECs) in vitro and the trachea in vivo. We hypothesized that some elements of the induced antiviral responses are distinct in both infection models. We inoculated cTECs and infected young specific pathogen-free (SPF) chickens with IBV DMV/1639 or IBV Mass41, along with mock-inoculated controls, and studied the transcriptome using RNA-sequencing (RNA-seq) at 3 and 18 h post-infection (hpi) for cTECs and at 4 and 11 days post-infection (dpi) in the trachea. We showed that IBV DMV/1639 and IBV Mass41 replicate in cTECs in vitro and the trachea in vivo, inducing host mRNA expression profiles that are strain- and time-dependent. We demonstrated the different gene expression patterns between in vitro and in vivo tracheal IBV infection. Ultimately, characterizing host-pathogen interactions with various IBV strains reveals potential mechanisms for inducing and modulating the immune response during IBV infection in the chicken trachea.

q-Diffusion leverages the full dimensionality of gene coexpression in single-cell transcriptomics

Unlocking the full dimensionality of single-cell RNA sequencing data (scRNAseq) is the next frontier to a richer, fuller understanding of cell biology. We introduce q-diffusion, a framework for capturing the coexpression structure of an entire library of genes, improving on state-of-the-art analysis tools. The method is demonstrated via three case studies. In the first, q-diffusion helps gain statistical significance for differential effects on patient outcomes when analyzing the CALGB/SWOG 80405 randomized phase III clinical trial, suggesting precision guidance for the treatment of metastatic colorectal cancer. Secondly, q-diffusion is benchmarked against existing scRNAseq classification methods using an in vitro PBMC dataset, in which the proposed method discriminates IFN-γ stimulation more accurately. The same case study demonstrates improvements in unsupervised cell clustering with the recent Tabula Sapiens human atlas. Finally, a local distributional segmentation approach for spatial scRNAseq, driven by q-diffusion, yields interpretable structures of human cortical tissue.

BTN1A1 is a novel immune checkpoint mutually exclusive to PD-L1

BACKGROUND

While Programmed cell death protein 1 (PD-1)/programmed cell death-ligand 1 (PD-L1) blockade is a potent antitumor treatment strategy, it is effective in only limited subsets of patients with cancer, emphasizing the need for the identification of additional immune checkpoints. Butyrophilin 1A1 (BTN1A1) has been reported to exhibit potential immunoregulatory activity, but its ability to function as an immune checkpoint remains to be systematically assessed, and the mechanisms underlying such activity have yet to be characterized.

METHODS

BTN1A1 expression was evaluated in primary tumor tissue samples, and its ability to suppress T-cell activation and T cell-dependent tumor clearance was examined. The relationship between BTN1A1 and PD-L1 expression was further characterized, followed by the development of a BTN1A1-specific antibody that was administered to tumor-bearing mice to test the amenability of this target to immune checkpoint inhibition.

RESULTS

BTN1A1 was confirmed to suppress T-cell activation in vitro and in vivo. Robust BTN1A1 expression was detected in a range of solid tumor tissue samples, and BTN1A1 expression was mutually exclusive with that of PD-L1 as a consequence of its inhibition of Janus-activated kinase/signal transducer and activator of transcription signaling-induced PD-L1 upregulation. Antibody-mediated BTN1A1 blockade suppressed tumor growth and enhanced immune cell infiltration in syngeneic tumor-bearing mice.

CONCLUSION

Together, these results confirm that the potential of BTN1A1 is a bona fide immune checkpoint and a viable immunotherapeutic target for the treatment of individuals with anti-PD-1/PD-L1 refractory or resistant disease, opening new avenues to improving survival outcomes for patients with a range of cancers.

Interferon gamma in the pathogenesis of hypertension - recent insights

PURPOSE OF REVIEW

The mounting body of evidence underscores the pivotal role of interferon gamma (IFNγ) in the pathogenesis of hypertension, prompting exploration of the mechanisms by which this cytokine fosters a pro-inflammatory immune milieu, subsequently exacerbating hypertension. In this review, we delve into recent preclinical and clinical studies from the past two years to elucidate how IFNγ participates in the progression of hypertension.

RECENT FINDINGS

IFNγ promotes renal CD8 + T cell accumulation by upregulating tubular PDL1 and MHC-I, intensifying cell-to-cell interaction. Intriguingly, a nucleotide polymorphism in LNK, predisposing towards hypertension, correlates with augmented T cell IFNγ production. Additionally, anti-IFNγ treatment exhibits protective effects against T cell-mediated inflammation during angiotensin II infusion or transverse aortic constriction. Moreover, knockout of the mineralocorticoid receptor in T cells protects against cardiac dysfunction induced by myocardial infarction, correlating with reduced IFNγ and IL-6, decreased macrophage recruitment, and attenuated fibrosis. Interestingly, increased IFNγ production correlates with elevated blood pressure, impacting individuals with type 2 diabetes, nondiabetics, and obese hypertensive patients.

SUMMARY

These revelations spotlight IFNγ as the critical mediator bridging the initial phase of blood pressure elevation with the sustained and exacerbated pathology. Consequently, blocking IFNγ signaling emerges as a promising therapeutic target to improve the management of this 'silent killer.'

Deregulation of interferon-gamma receptor 1 expression and its implications for lung adenocarcinoma progression

Interferon-gamma (IFN-γ) plays a dual role in cancer; it is both a pro- and an antitumorigenic cytokine, depending on the type of cancer. The deregulation of the IFN-γ canonic pathway is associated with several disorders, including vulnerability to viral infections, inflammation, and cancer progression. In particular, the interplay between lung adenocarcinoma (LUAD) and viral infections appears to exist in association with the deregulation of IFN-γ signaling. In this mini-review, we investigated the status of the IFN-γ signaling pathway and the expression level of its components in LUAD. Interestingly, a reduction in IFNGR1 expression seems to be associated with LUAD progression, affecting defenses against viruses such as severe acute respiratory syndrome coronavirus 2. In addition, alterations in the expression of IFNGR1 may inhibit the antiproliferative action of IFN-γ signaling in LUAD.

LATS1/2 loss promote tumor immune evasion in endometrial cancer through downregulating MHC-I expression

BACKGROUND

LATS1/2 are frequently mutated and down-regulated in endometrial cancer (EC), but the contributions of LATS1/2 in EC progression remains unclear. Impaired antigen presentation due to mutations or downregulation of the major histocompatibility complex class I (MHC-I) has been implicated in tumor immune evasion. Herein, we elucidate the oncogenic role that dysregulation of LATS1/2 in EC leads to immune evasion through the down-regulation of MHC-I.

METHODS

The mutation and expression as well as the clinical significance of LATS1/2 in EC was assessed in the TCGA cohort and our sample cohort. CRISPR-Cas9 was used to construct knockout cell lines of LATS1/2 in EC. Differentially expressed genes were analyzed by RNA-seq. The interaction between LATS1/2 and STAT1 was verified using co-immunoprecipitation and GST pull-down assays. Mass spectrometry, in vitro kinase assays, ChIP-qPCR, flow cytometry, immunohistochemistry, immunofluorescence and confocal microscopy were performed to investigate the regulation of LATS1/2 on MHC-I through interaction with and phosphorylate STAT1. The killing effect of activated PBMCs on EC cells were used to monitor anti-tumor activity.

RESULTS

Here, we demonstrate that LATS1/2 are frequently mutated and down-regulated in EC. Moreover, LATS1/2 loss was found to be associated with a significant down-regulation of MHC-I, independently of the Hippo-YAP pathway. Instead, LATS1/2 were found to directly interact with and phosphorylate STAT1 at Ser727, a crucial transcription factor for MHC-I upregulation in response to interferon-gamma (IFN-γ) signaling, to promote STAT1 accumulating and moving into the nucleus to enhance the transcriptional activation of IRF1/NLRC5 on MHC-I. Additionally, the loss of LATS1/2 was observed to confer increased resistance of EC cells to immune cell-mediated killing and this resistance could be reversed by over-expression of MHC-I.

CONCLUSION

Our findings indicate that dysregulation of LATS1/2 in EC leads to immune evasion through the down-regulation of MHC-I, leading to the suppression of infiltrating activated CD8 + T cells and highlight the importance of LATS1/2 in IFN-γ signaling-mediated tumor immune response, suggesting that LATS1/2 is a promising target for immune checkpoint blockade therapy in EC.

Cytokine Storm Syndrome Associated with Systemic Juvenile Idiopathic Arthritis

The cytokine storm syndrome (CSS) associated with systemic juvenile idiopathic arthritis (sJIA) has widely been referred to as macrophage activation syndrome (MAS). In this chapter, we use the term sJIA-associated CSS (sJIA-CSS) when referring to this syndrome and use the term MAS when referencing publications that specifically report on sJIA-associated MAS.

Discovering common pathogenetic processes between COVID-19 and tuberculosis by bioinformatics and system biology approach

Introduction

The coronavirus disease 2019 (COVID-19) pandemic, stemming from the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has persistently threatened the global health system. Meanwhile, tuberculosis (TB) caused by Mycobacterium tuberculosis (M. tuberculosis) still continues to be endemic in various regions of the world. There is a certain degree of similarity between the clinical features of COVID-19 and TB, but the underlying common pathogenetic processes between COVID-19 and TB are not well understood.

Methods

To elucidate the common pathogenetic processes between COVID-19 and TB, we implemented bioinformatics and systematic research to obtain shared pathways and molecular biomarkers. Here, the RNA-seq datasets (GSE196822 and GSE126614) are used to extract shared differentially expressed genes (DEGs) of COVID-19 and TB. The common DEGs were used to identify common pathways, hub genes, transcriptional regulatory networks, and potential drugs.

Results

A total of 96 common DEGs were selected for subsequent analyses. Functional enrichment analyses showed that viral genome replication and immune-related pathways collectively contributed to the development and progression of TB and COVID-19. Based on the protein-protein interaction (PPI) network analysis, we identified 10 hub genes, including IFI44L, ISG15, MX1, IFI44, OASL, RSAD2, GBP1, OAS1, IFI6, and HERC5. Subsequently, the transcription factor (TF)-gene interaction and microRNA (miRNA)-gene coregulatory network identified 61 TFs and 29 miRNAs. Notably, we identified 10 potential drugs to treat TB and COVID-19, namely suloctidil, prenylamine, acetohexamide, terfenadine, prochlorperazine, 3'-azido-3'-deoxythymidine, chlorophyllin, etoposide, clioquinol, and propofol.

Conclusion

This research provides novel strategies and valuable references for the treatment of tuberculosis and COVID-19.

SARS-CoV-2 vaccination enhances the effector qualities of spike-specific T cells induced by COVID-19

T cells are critical for immune protection against severe COVID-19, but it has remained unclear whether repeated exposure to SARS-CoV-2 antigens delivered in the context of vaccination fuels T cell exhaustion or reshapes T cell functionality. Here, we sampled convalescent donors with a history of mild or severe COVID-19 before and after SARS-CoV-2 vaccination to profile the functional spectrum of hybrid T cell immunity. Using combined single-cell technologies and high-dimensional flow cytometry, we found that the frequencies and functional capabilities of spike-specific CD4+ and CD8+ T cells in previously infected individuals were enhanced by vaccination, despite concomitant increases in the expression of inhibitory receptors such as PD-1 and TIM3. In contrast, CD4+ and CD8+ T cells targeting non-spike proteins remained functionally static and waned over time, and only minimal effects were observed in healthy vaccinated donors experiencing breakthrough infections with SARS-CoV-2. Moreover, hybrid immunity was characterized by elevated expression of IFN-γ, which was linked with clonotype specificity in the CD8+ T cell lineage. Collectively, these findings identify a molecular hallmark of hybrid immunity and suggest that vaccination after infection is associated with cumulative immunological benefits over time, potentially conferring enhanced protection against subsequent episodes of COVID-19.

Immunoregulation mechanism of VEGF signaling pathway inhibitors and its efficacy on the kidney

Angiogenesis and immunosuppression are closely related pathophysiologic processes. Widely prescribed in malignant tumor and proliferative retinal lesions, VEGF signaling pathway inhibitors may cause hypertension and renal injury in some patients, presenting with proteinuria, nephrotic syndrome, renal failure and thrombotic microangiopathy. VEGF signaling pathway inhibitors block the action of both VEGF-A and VEGF-C. However, VEGF-A and VEGF-C produced by podocytes are vital to maintain the physiological function of glomerular endothelial cells and podocytes. There is still no effective treatment for kidney disease associated with VEGF signaling pathway inhibitors and some patients have progressive renal failure even after withdrawal of the drug. Recent studies reveal that blocking of VEGF-A and VEGF-C can activate CD4 +and CD8+ T cells, augment antigen-presenting function of dendritic cells, enhance cytotoxicity of macrophages and initiate complement cascade activation. VEGF and VEGFR are expressed in immune cells, which are involved in the immunosuppression and cross-talk among immune cells. This review summarizes the expression and function of VEGF-A and VEGF-C in the kidney. The current immunoregulation mechanisms of VEGF signaling pathway inhibitors are reviewed. Finally, combinate strategies are summarized to highlight the proposal for VEGF signaling pathway inhibitors.

Interferon-γ couples CD8+ T cell avidity and differentiation during infection

Effective responses to intracellular pathogens are characterized by T cell clones with a broad affinity range for their cognate peptide and diverse functional phenotypes. How T cell clones are selected throughout the response to retain a breadth of avidities remains unclear. Here, we demonstrate that direct sensing of the cytokine IFN-γ by CD8+ T cells coordinates avidity and differentiation during infection. IFN-γ promotes the expansion of low-avidity T cells, allowing them to overcome the selective advantage of high-avidity T cells, whilst reinforcing high-avidity T cell entry into the memory pool, thus reducing the average avidity of the primary response and increasing that of the memory response. IFN-γ in this context is mainly provided by virtual memory T cells, an antigen-inexperienced subset with memory features. Overall, we propose that IFN-γ and virtual memory T cells fulfil a critical immunoregulatory role by enabling the coordination of T cell avidity and fate.

TCR-Engineered Lymphocytes Targeting NY-ESO-1: In Vitro Assessment of Cytotoxicity against Tumors

Adoptive T-cell therapies tailored for the treatment of solid tumors encounter intricate challenges, necessitating the meticulous selection of specific target antigens and the engineering of highly specific T-cell receptors (TCRs). This study delves into the cytotoxicity and functional characteristics of in vitro-cultured T-lymphocytes, equipped with a TCR designed to precisely target the cancer-testis antigen NY-ESO-1. Flow cytometry analysis unveiled a notable increase in the population of cells expressing activation markers upon encountering the NY-ESO-1-positive tumor cell line, SK-Mel-37. Employing the NanoString platform, immune transcriptome profiling revealed the upregulation of genes enriched in Gene Ontology Biological Processes associated with the IFN-γ signaling pathway, regulation of T-cell activation, and proliferation. Furthermore, the modified T cells exhibited robust cytotoxicity in an antigen-dependent manner, as confirmed by the LDH assay results. Multiplex immunoassays, including LEGENDplex™, additionally demonstrated the elevated production of cytotoxicity-associated cytokines driven by granzymes and soluble Fas ligand (sFasL). Our findings underscore the specific targeting potential of engineered TCR T cells against NY-ESO-1-positive tumors. Further comprehensive in vivo investigations are essential to thoroughly validate these results and effectively harness the intrinsic potential of genetically engineered T cells for combating cancer.

Isolating salient variations of interest in single-cell data with contrastiveVI

Single-cell datasets are routinely collected to investigate changes in cellular state between control cells and the corresponding cells in a treatment condition, such as exposure to a drug or infection by a pathogen. To better understand heterogeneity in treatment response, it is desirable to deconvolve variations enriched in treated cells from those shared with controls. However, standard computational models of single-cell data are not designed to explicitly separate these variations. Here, we introduce contrastive variational inference (contrastiveVI; https://github.com/suinleelab/contrastiveVI ), a framework for deconvolving variations in treatment-control single-cell RNA sequencing (scRNA-seq) datasets into shared and treatment-specific latent variables. Using three treatment-control scRNA-seq datasets, we apply contrastiveVI to perform a variety of analysis tasks, including visualization, clustering and differential expression testing. We find that contrastiveVI consistently achieves results that agree with known ground truths and often highlights subtle phenomena that may be difficult to ascertain with standard workflows. We conclude by generalizing contrastiveVI to accommodate joint transcriptome and surface protein measurements.

Effect of pro-inflammatory cytokine priming and storage temperature of the mesenchymal stromal cell (MSC) secretome on equine articular chondrocytes

Context: Osteoarthritis (OA) is an invalidating articular disease characterized by cartilage degradation and inflammatory events. In horses, OA is associated with up to 60% of lameness and leads to reduced animal welfare along with extensive economic losses; currently, there are no curative therapies to treat OA. The mesenchymal stromal cell (MSC) secretome exhibits anti-inflammatory properties, making it an attractive candidate for improving the management of OA. In this study, we determined the best storage conditions for conditioned media (CMs) and tested whether priming MSCs with cytokines can enhance the properties of the MSC secretome. Methods: First, properties of CMs collected from bone-marrow MSC cultures and stored at -80°C, -20°C, 4°C, 20°C or 37°C were assessed on 3D cultures of equine articular chondrocytes (eACs). Second, we primed MSCs with IL-1β, TNF-α or IFN-γ, and evaluated the MSC transcript levels of immunomodulatory effectors and growth factors. The primed CMs were also harvested for subsequent treatment of eACs, either cultured in monolayers or as 3D cell cultures. Finally, we evaluated the effect of CMs on the proliferation and the phenotype of eACs and the quality of the extracellular matrix of the neosynthesized cartilage. Results: CM storage at -80°C, -20°C, and 4°C improved collagen protein accumulation, cell proliferation and the downregulation of inflammation. The three cytokines chosen for the MSC priming influenced MSC immunomodulator gene expression, although each cytokine led to a different pattern of MSC immunomodulation. The cytokine-primed CM had no major effect on eAC proliferation, with IL-1β and TNF-α slightly increasing collagen (types IIB and I) accumulation in eAC 3D cultures (particularly with the CM derived from MSCs primed with IL-1β), and IFN-γ leading to a marked decrease. IL-1β-primed CMs resulted in increased eAC transcript levels of MMP1, MMP13 and HTRA1, whereas IFNγ-primed CMs decreased the levels of HTRA1 and MMP13. Conclusion: Although the three cytokines differentially affected the expression of immunomodulatory molecules, primed CMs induced a distinct effect on eACs according to the cytokine used for MSC priming. Different mechanisms seemed to be triggered by each priming cytokine, highlighting the need for further investigation. Nevertheless, this study demonstrates the potential of MSC-CMs for improving equine OA management.

Molecular and Cellular Mechanisms of Action of Cannabidiol

Cannabidiol (CBD) is the primary non-psychoactive chemical from Cannabis Sativa, a plant used for centuries for both recreational and medicinal purposes. CBD lacks the psychotropic effects of Δ9-tetrahydrocannabinol (Δ9-THC) and has shown great therapeutic potential. CBD exerts a wide spectrum of effects at a molecular, cellular, and organ level, affecting inflammation, oxidative damage, cell survival, pain, vasodilation, and excitability, among others, modifying many physiological and pathophysiological processes. There is evidence that CBD may be effective in treating several human disorders, like anxiety, chronic pain, psychiatric pathologies, cardiovascular diseases, and even cancer. Multiple cellular and pre-clinical studies using animal models of disease and several human trials have shown that CBD has an overall safe profile. In this review article, we summarize the pharmacokinetics data, the putative mechanisms of action of CBD, and the physiological effects reported in pre-clinical studies to give a comprehensive list of the findings and major effects attributed to this compound.

IFNγ is a central node of cancer immune equilibrium

Tumors in immune equilibrium are held in balance between outgrowth and destruction by the immune system. The equilibrium phase defines the duration of clinical remission and stable disease, and escape from equilibrium remains a major clinical problem. Using a non-replicating HSV-1 vector expressing interleukin-12 (d106S-IL12), we developed a mouse model of therapy-induced immune equilibrium, a phenomenon previously seen only in humans. This immune equilibrium was centrally reliant on interferon-γ (IFNγ). CD8+ T cell direct recognition of MHC class I, perforin/granzyme-mediated cytotoxicity, and extrinsic death receptor signaling such as Fas/FasL were all individually dispensable for equilibrium. IFNγ was critically important and played redundant roles in host and tumor cells such that IFNγ sensing in either compartment was sufficient for immune equilibrium. We propose that these redundant mechanisms of action are integrated by IFNγ to protect from oncogenic or chronic viral threats and establish IFNγ as a central node in therapy-induced immune equilibrium.

Expression of Human Endogenous Retrovirus Group K (HERV-K) HML-2 Correlates with Immune Activation of Macrophages and Type I Interferon Response

Human endogenous retroviruses (HERVs) comprise about 8.3% of the human genome and are capable of producing RNA molecules that can be sensed by pattern recognition receptors, leading to the activation of innate immune response pathways. The HERV-K (HML-2) subgroup is the youngest HERV clade with the highest degree of coding competence. Its expression is associated with inflammation-related diseases. However, the precise HML-2 loci, stimuli, and signaling pathways involved in these associations are not well understood or defined. To elucidate HML-2 expression on a locus-specific level, we used the retroelement sequencing tools TEcount and Telescope to analyze publicly available transcriptome sequencing (RNA-seq) and chromatin immunoprecipitation (ChIP) sequencing data sets of macrophages treated with a wide range of agonists. We found that macrophage polarization significantly correlates with modulation of the expression of specific HML-2 proviral loci. Further analysis demonstrated that the provirus HERV-K102, located in an intergenic region of locus 1q22, constituted the majority of the HML-2 derived transcripts following pro-inflammatory (M1) polarization and was upregulated explicitly in response to interferon gamma (IFN-γ) signaling. We found that signal transducer and activator of transcription 1 and interferon regulatory factor 1 interact with a solo long terminal repeat (LTR) located upstream of HERV-K102, termed LTR12F, following IFN-γ signaling. Using reporter constructs, we demonstrated that LTR12F is critical for HERV-K102 upregulation by IFN-γ. In THP1-derived macrophages, knockdown of HML-2 or knockout of MAVS, an adaptor of RNA-sensing pathways, significantly downregulated genes containing interferon-stimulated response elements (ISREs) in their promoters, suggesting an intermediate role of HERV-K102 in the switch from IFN-γ signaling to the activation of type I interferon expression and, therefore, in a positive feedback loop to enhance pro-inflammatory signaling. IMPORTANCE The human endogenous retrovirus group K subgroup, HML-2, is known to be elevated in a long list of inflammation-associated diseases. However, a clear mechanism for HML-2 upregulation in response to inflammation has not been defined. In this study, we identify a provirus of the HML-2 subgroup, HERV-K102, which is significantly upregulated and constitutes the majority of the HML-2 derived transcripts in response to pro-inflammatory activation of macrophages. Moreover, we identify the mechanism of HERV-K102 upregulation and demonstrate that HML-2 expression enhances interferon-stimulated response element activation. We also demonstrate that this provirus is elevated in vivo and correlates with interferon gamma signaling activity in cutaneous leishmaniasis patients. This study provides key insights into the HML-2 subgroup and suggests that it may participate in enhancing pro-inflammatory signaling in macrophages and probably other immune cells.

African Swine Fever Virus Infection and Cytokine Response In Vivo: An Update

African swine fever (ASF) is a hemorrhagic viral disease of domestic pigs and wild suids (all Sus scrofa) caused by the ASF virus (ASFV). The disease is spreading worldwide without control, threatening pig production due to the absence of licensed vaccine or commercially available treatments. A thorough understanding of the immunopathogenic mechanisms behind ASFV infection is required to better fight the disease. Cytokines are small, non-structural proteins, which play a crucial role in many aspects of the immune responses to viruses, including ASFV. Infection with virulent ASFV isolates often results in exacerbated immune responses, with increased levels of serum pro-inflammatory interleukins (IL-1α, IL-1β, IL-6), TNF and chemokines (CCL2, CCL5, CXCL10). Increased levels of IL-1, IL-6 and TNF are often detected in several tissues during acute ASFV infections and associated with lymphoid depletion, hemorrhages and oedemas. IL-1Ra is frequently released during ASFV infection to block further IL-1 activity, with its implication in ASFV immunopathology having been suggested. Increased levels of IFN-α and of the anti-inflammatory IL-10 seem to be negatively correlated with animal survival, whereas some correlation between virus-specific IFN-γ-producing cells and protection has been suggested in different studies where different vaccine candidates were tested, although future works should elucidate whether IFN-γ release by specific cell types is related to protection or disease development.

Prognostic biomarker GSTK1 in head and neck squamous cell carcinoma and its correlation with immune infiltration and DNA methylation

Background: Glutathione S-transferase kappa 1 (GSTK1) is critical in sarcoma and breast cancer (BRCA) development. However, the clinical significance of GSTK1 in head and neck squamous cell carcinoma (HNSC) remains unclear. This study is the first investigation into the role of GSTK1 in HNSC. Methods: All original data were downloaded from the Cancer Genome Atlas (TCGA) dataset and verified by R Base Package 4.2.0. The expression of GSTK1 in various cancers was explored with TIMER and TCGA databases. Prognostic value of GSTK1 was analyzed via survival module of Kaplan-Meier plotter and Human Protein Atlas database and Cox regression analysis. The association between GSTK1 and clinical features was evaluated by Wilcoxon signed-rank test and logistic regression analysis. The relationship between GSTK1 and immune infiltration and methylation level was further explored. The expression of GSTK1 and its correlation with immune cell infiltration was verified by Immunohistochemical staining (IHC). Results: GSTK1 was lower in HNSC, BRCA, Lung squamous cell carcinoma, and Thyroid carcinoma than in para-carcinoma. Low GSTK1 expression was associated with worse overall survival in Bladder urothelial carcinoma, Kidney renal papillary cell carcinoma, BRCA, and HNSC. However, only in BRCA and HNSC, GSTK1 expression in tumors was lower than that in normal tissues. Cox regression analyses confirmed that GSKT1 was an independent prognostic factor of overall survival in HNSC patients. The decrease in GSTK1 expression in HNSC was significantly correlated with high T stage and smoker history. IHC showed that the expression level of GSTK1 in HNSC was lower than that in para-carcinoma. In addition, GSEA showed that three pathways related to immune infiltration were positively correlated, while two pathways related to DNA methylation were negatively correlated with expression of GSTK1. Further analysis showed that GSTK1 was moderately positively correlated with the infiltration level of T cells and Cytotoxic cells, which was further confirmed by IHC. The methylation level of GSTK1 was associated with prognosis in patients with HNSC. Conclusion: Low GSTK1 expression may be a potential molecular marker for poor prognosis in HNSC and provide new insight for the development of diagnostic marker or therapeutic target.

IFN-γ Contributes to the Immune Mechanisms of Hypertension

Hypertension is the leading cause of cardiovascular disease and the primary risk factor for mortality worldwide. For more than half a century, researchers have demonstrated that immunity plays an important role in the development of hypertension; however, the precise mechanisms are still under investigation. The current body of knowledge indicates that proinflammatory cytokines may play an important role in contributing to immune-related pathogenesis of hypertension. Interferon gamma (IFN-γ), in particular, as an important cytokine that modulates immune responses, has been recently identified as a critical regulator of blood pressure by several groups, including us. In this review, we focus on exploring the role of IFN-γ in contributing to the pathogenesis of hypertension, outlining the various immune producers of this cytokine and described signaling mechanisms involved. We demonstrate a key role for IFN-γ in hypertension through global knockout studies and related downstream signaling pathways that IFN-γ production from CD8+ T cell (CD8T) in the kidney promoting CD8T-stimulated salt retention via renal tubule cells, thereby exacerbating hypertension. We discuss potential activators of these T cells described by the current literature and relay a novel hypothesis for activation.

Interferon-gamma modulates articular chondrocyte and osteoblast metabolism through protein kinase R-independent and dependent mechanisms

Osteoarthritis (OA) affects multiple tissues of the synovial joint and is characterised by articular cartilage degeneration and bone remodelling. Interferon-γ (IFN-γ) is implicated in osteoarthritis pathology exerting its biological effects via various mechanisms including activation of protein kinase R (PKR), which has been implicated in inflammation and arthritis. This study investigated whether treatment of articular cartilage chondrocytes and osteoblasts with IFN-γ could induce a degradative phenotype that was mediated through the PKR signalling pathway. IFN-γ treatment of chondrocytes increased transcription of key inflammatory mediators (TNF-α, IL-6), matrix degrading enzymes (MMP-13), the transcription factor STAT1, and PKR. Activation of PKR was involved in the regulation of TNF-α, IL-6, and STAT1. In osteoblasts, IFN-γ increased human and mouse STAT1, and human IL-6 through a mechanism involving PKR. ALP, COL1A1 (human and mouse), RUNX2 (mouse), and PHOSPHO1 (mouse) were decreased by IFN-γ. The number of PKR positive cells were increased in post-traumatic OA (PTOA). This study has revealed that IFN-γ propagates inflammatory and degenerative events in articular chondrocytes and osteoblasts via PKR activation. Since IFN-γ and PKR signalling are both activated in early PTOA, these mechanisms are likely to contribute to joint degeneration after injury and might offer attractive targets for therapeutic intervention.

•IFN-γ treatment of chondrocytes increased transcription of TNF-α, IL-6, and STAT1 via PKR activation.

•In osteoblasts, IFN-γ increased STAT1 and IL-6 via PKR activation.

•The number of PKR positive cells were increased in post-traumatic OA (PTOA).

•IFN-γ propagates inflammatory and degenerative events in articular chondrocytes and osteoblasts via PKR activation.

•IFN-γ and PKR signalling are both activated in early PTOA and are likely to contribute to joint degeneration after injury.

Efficacy and safety of tofacitinib for treatment of alopecia areata in children: A systematic review and meta-analysis

BACKGROUND

Tofacitinib, a potent JAK inhibitor, has gained increasing interest, in recent years, among dermatologists for the management of refractory alopecia areata. Despite a growing number of studies on its safety and efficacy, there is still a lack of clarity, especially in the pediatric population, in treatment considerations such as proper dosage, treatment duration, side-effect profile, and therapeutic strategies to guide clinicians.

METHODS

Multiple databases were systematically searched. Following the PRISMA diagram, of a pool of 601 papers, seven met a checklist of inclusion criteria. These were observational studies including a total of 59 patients from four to 19 years of age.

RESULTS

In the evaluated studies, tofacitinib was administered either orally at a 2.5 to 15 mg daily (mostly 5 mg twice a day) dosage for 2 to 38 months or in the form of a 2% topical solution for 3-17 months. Metanalysis showed that 49% (95% CI: 29%-69%, I²  = 59.94%) of patients experienced a reversal of alopecia after a minimum of 3 to 9 months of therapy. Fifty-five percent (95% CI: 23%-86%, I²  = 75.07%) and 41% (95% CI: 23%-59%, I²  = 0.00%) showed Good/complete and partial response rates, respectively. Oral administration was significantly more efficacious than topical application (73% vs 23%, p-Value = 0.04). Few side effects such as diarrhea and mild liver transaminases abnormalities were noted in several patients.

CONCLUSION

Results of this review suggest that tofacitinib at 2.5-15 mg daily (especially 5 mg twice daily) oral formulation or 2% topical solution can be regarded as a viable alternative or adjunct to the conventional treatment options for moderate to severe forms of alopecia areata in children owing to its acceptable efficacy and side-effect profile. However, uncertainties continue to exist around treatment strategies including initial and maintenance dosages, route of administration, dose adjustments, the timing of tapering or discontinuation, and associated treatment modalities.

SRSF1 acts as an IFN-I-regulated cellular dependency factor decisively affecting HIV-1 post-integration steps

Efficient HIV-1 replication depends on balanced levels of host cell components including cellular splicing factors as the family of serine/arginine-rich splicing factors (SRSF, 1-10). Type I interferons (IFN-I) play a crucial role in the innate immunity against HIV-1 by inducing the expression of IFN-stimulated genes (ISGs) including potent host restriction factors. The less well known IFN-repressed genes (IRepGs) might additionally affect viral replication by downregulating host dependency factors that are essential for the viral life cycle; however, so far, the knowledge about IRepGs involved in HIV-1 infection is very limited. In this work, we could demonstrate that HIV-1 infection and the associated ISG induction correlated with low SRSF1 levels in intestinal lamina propria mononuclear cells (LPMCs) and peripheral blood mononuclear cells (PBMCs) during acute and chronic HIV-1 infection. In HIV-1-susceptible cell lines as well as primary monocyte-derived macrophages (MDMs), expression levels of SRSF1 were transiently repressed upon treatment with specific IFNα subtypes in vitro. Mechanically, 4sU labeling of newly transcribed mRNAs revealed that IFN-mediated SRSF1 repression is regulated on early RNA level. SRSF1 knockdown led to an increase in total viral RNA levels, but the relative proportion of the HIV-1 viral infectivity factor (Vif) coding transcripts, which is essential to counteract APOBEC3G-mediated host restriction, was significantly reduced. In the presence of high APOBEC3G levels, however, increased LTR activity upon SRSF1 knockdown facilitated the overall replication, despite decreased vif mRNA levels. In contrast, SRSF1 overexpression significantly impaired HIV-1 post-integration steps including LTR transcription, alternative splice site usage, and virus particle production. Since balanced SRSF1 levels are crucial for efficient viral replication, our data highlight the so far undescribed role of SRSF1 acting as an IFN-modulated cellular dependency factor decisively regulating HIV-1 post-integration steps.

The Expression of the Immunoproteasome Subunit PSMB9 Is Related to Distinct Molecular Subtypes of Uterine Leiomyosarcoma

Simple Summary

Uterine leiomyosarcoma (uLMS) is a rare, aggressive, and highly heterogeneous tumor. Knockout female mice for the catalytic subunit of the immunoproteasome PSMB9 develops spontaneous uLMS. In this study, we used molecular data from 3 non-related uLMS cohorts that were integrated and analyzed by proteotranscriptomics. We observed overexpression of the immunoproteasome pathway in uLMS, and then further classified the samples as low or high PSMB9 gene expression levels and we provide evidence that; (i) in the group high there is an enrichment of pathways related to the immune system and in the group low, the ECM formation; (ii) samples with high CD8+/PSMB9 ratio shows better OS; and (iii) the main regulator in the high group is IFNγ and in the low, the proto-oncogene SRC. These findings contribute to the understanding of potential therapeutic or prognostic markers in uLMS.

Abstract

Background: Uterine leiomyosarcoma (uLMS) are rare and malignant tumors that arise in the myometrium cells and whose diagnosis is based on histopathological features. Identifying diagnostic biomarkers for uLMS is a challenge due to molecular heterogeneity and the scarcity of samples. In vivo and in vitro models for uLMS are urgently needed. Knockout female mice for the catalytic subunit of the immunoproteasome PSMB9 (MIM:177045) develop spontaneous uLMS. This study aimed to analyze the role of PSMB9 in uLMS tumorigenesis and patient outcome. Methods: Molecular data from 3 non-related uLMS cohorts were integrated and analyzed by proteotranscriptomic using gene expression and protein abundance levels in 68 normal adjacent myometrium (MM), 66 uterine leiomyoma (LM), and 67 uLMS. Results: the immunoproteasome pathway is upregulated and the gene PMSB9 shows heterogeneous expression values in uLMS. Quartile group analysis showed no significant difference between groups high and low PSMB9 expression groups at 3-years overall survival (OS). Using CYBERSORTx analysis we observed 9 out of 17 samples in the high group clustering together due to high M2 macrophages and CD4 memory resting, and high CD8+/PSMB9 ratio was associated with better OS. The main pathway regulated in the high group is IFNγ and in the low is the ECM pathway dependent on the proto-oncogene SRC. Conclusion: these findings suggest 2 subtypes of uLMS (immune-related and ECM-related) with different candidate mechanisms of malignancy.

Role of interferon-gamma (IFN-γ) and IFN-γ receptor 1/2 (IFNγR1/2) in regulation of immunity, infection, and cancer development: IFN-γ-dependent or independent pathway

IFN-γ, a soluble cytokine being produced by T lymphocytes, macrophages, mucosal epithelial cells, or natural killer cells, is able to bind to the IFN-γ receptor (IFNγR) and in turn activate the Janus kinase (JAK)-signal transducer and transcription protein (STAT) pathway and induce expression of IFN-γ-stimulated genes. IFN-γ is critical for innate and adaptive immunity and aberrant IFN-γ expression and functions have been associated with different human diseases. However, the IFN-γ/IFNγR signaling could be a double-edged sword in cancer development because the tissue microenvironments could determine its anti- or pro-tumorigenic activities. The IFNγR protein consists of two IFNγR1 and IFNγR2 chains, subunits of which play different roles under certain conditions. This review assessed IFNγR polymorphisms, expression and functions in development and progression of various human diseases in an IFN-γ-dependent or independent manner. This review also discussed tumor microenvironment, microbial infection, and vital molecules in the IFN-γ upstream signaling that might regulate IFNγR expression, drug resistance, and druggable strategy, to provide evidence for further application of IFNγR.

Comprehensive Serum Proteome Profiling of Cytokine Release Syndrome and Immune Effector Cell-Associated Neurotoxicity Syndrome Patients with B-Cell ALL Receiving CAR T19

PURPOSE

To study the biology and identify markers of severe cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) in children after chimeric antigen receptor T-cell (CAR T) treatment.

EXPERIMENTAL DESIGN

We used comprehensive proteomic profiling to measure over 1,400 serum proteins at multiple serial timepoints in a cohort of patients with B-cell acute lymphoblastic leukemia treated with the CD19-targeted CAR T CTL019 on two clinical trials.

RESULTS

We identified fms-like tyrosine kinase 3 (FLT3) and mast cell immunoglobulin-like receptor 1 (MILR1) as preinfusion predictive biomarkers of severe CRS. We demonstrated that CRS is an IFNγ-driven process with a protein signature overlapping with hemophagocytic lymphohistiocytosis (HLH). We identified IL18 as a potentially targetable cytokine associated with the development of ICANS.

CONCLUSIONS

We identified preinfusion biomarkers that can be used to predict severe CRS with a sensitivity, specificity, and accuracy superior to the current gold standard of disease burden. We demonstrated the fundamental role of the IFNγ pathway in driving CRS, suggesting CRS and carHLH are overlapping rather than distinct phenomena, an observation with important treatment implications. We identified IL18 as a possible targetable cytokine in ICANS, providing rationale for IL18 blocking therapies to be translated into clinical trials in ICANS.

A STAT5-Smad3 dyad regulates adipogenic plasticity of visceral adipose mesenchymal stromal cells during chronic inflammation

Adipogenic differentiation of visceral adipose tissue-resident multipotent mesenchymal stromal cells (VA-MSC) into adipocytes is metabolically protective. Under chronic inflammatory stress, this neoadipogenesis process is suppressed by various pro-inflammatory cytokines and growth factors. However, the underlying mechanism(s) regulating VA-MSC plasticity remains largely unexplored. Using an adipogenic differentiation screen, we identified IFNγ and TGFβ as key inhibitors of primary human VA-MSC differentiation. Further studies using human and mouse VA-MSCs and a chronic high-fat diet-fed murine model revealed that IFNγ/JAK2-activated STAT5 transcription factor is a central regulator of VA-MSC differentiation under chronic inflammatory conditions. Furthermore, our results indicate that under such conditions, IFNγ-activated STAT5 and TGFβ-activated Smad3 physically interact via Smad4. This STAT5-Smad4-Smad3 complex plays a crucial role in preventing the early adipogenic commitment of VA-MSCs by suppressing key pro-adipogenic transcription factors, including CEBPδ, CEBPα, and PPARγ. Genetic or pharmacological disruption of IFNγ-TGFβ synergy by inhibiting either STAT5 or Smad3 rescued adipogenesis under chronic inflammatory stress. Overall, our study delineates a central mechanism of MSC plasticity regulation by the convergence of multiple inflammatory signaling pathways.

Serum interferon-α2 measured by single-molecule array associates with systemic disease manifestations in Sjögren's syndrome

OBJECTIVES

Type I IFN (IFN-I) activation is a prominent feature of primary SS (pSS), SLE and SSc. Ultrasensitive single-molecule array (Simoa) technology has facilitated the measurement of subfemtomolar concentrations of IFNs. Here we aimed to measure IFN-α2 in serum from pSS, SLE and SSc using a Simoa immunoassay and correlate these levels to blood IFN-stimulated gene (ISG) expression and disease activity.

METHODS

Serum IFN-α2 was measured in patients with pSS (n = 85 and n = 110), SLE (n = 24) and SSc (n = 23) and healthy controls (HCs; n = 68) using an IFN-α Simoa assay on an HD-X analyser. IFN-I pathway activation was additionally determined from serum by an IFN-I reporter assay and paired samples of whole blood ISG expression of IFI44, IFI44L, IFIT1, IFIT3 and MxA by RT-PCR or myxovirus resistance protein 1 (MxA) protein ELISA.

RESULTS

Serum IFN-α2 levels were elevated in pSS (median 61.3 fg/ml) compared with HCs (median ≤5 fg/ml, P < 0.001) and SSc (median 11.6 fg/ml, P = 0.043), lower compared with SLE (median 313.5 fg/ml, P = 0.068) and positively correlated with blood ISG expression (r = 0.66-0.94, P < 0.001). Comparable to MxA ELISA [area under the curve (AUC) 0.93], IFN-α2 measurement using Simoa identified pSS with high ISG expression (AUC 0.90) with 80-93% specificity and 71-84% sensitivity. Blinded validation in an independent pSS cohort yielded a comparable accuracy. Multiple regression indicated independent associations of autoantibodies, IgG, HCQ treatment, cutaneous disease and a history of extraglandular manifestations with serum IFN-α2 concentrations in pSS.

CONCLUSION

Simoa serum IFN-α2 reflects blood ISG expression in pSS, SLE and SSc. In light of IFN-targeting treatments, Simoa could potentially be applied for patient stratification or retrospective analysis of historical cohorts.

IFNγ Regulates NAD+ Metabolism to Promote the Respiratory Burst in Human Monocytes

IFNγ is an essential and pleiotropic activator of human monocytes, but little is known about the changes in cellular metabolism required for IFNγ-induced activation. We sought to elucidate the mechanisms by which IFNγ reprograms monocyte metabolism to support its immunologic activities. We found that IFNγ increased oxygen consumption rates (OCR) in monocytes, indicative of reactive oxygen species generation by both mitochondria and NADPH oxidase. Transcriptional profiling revealed that this oxidative phenotype was driven by IFNγ-induced reprogramming of NAD+ metabolism, which is dependent on nicotinamide phosphoribosyltransferase (NAMPT)-mediated NAD+ salvage to generate NADH and NADPH for oxidation by mitochondrial complex I and NADPH oxidase, respectively. Consistent with this pathway, monocytes from patients with gain-of-function mutations in STAT1 demonstrated higher than normal OCR. Whereas chemical or genetic disruption of mitochondrial complex I (rotenone treatment or Leigh Syndrome patient monocytes) or NADPH oxidase (DPI treatment or chronic granulomatous disease (CGD) patient monocytes) reduced OCR. Interestingly, inhibition of NAMPT in healthy monocytes completely abrogated the IFNγ-induced oxygen consumption, comparable to levels observed in CGD monocytes. These data identify an IFNγ-induced, NAMPT-dependent, NAD+ salvage pathway that is critical for IFNγ activation of human monocytes.

APOE4 confers transcriptomic and functional alterations to primary mouse microglia

Common genetic variants in more than forty loci modulate risk for Alzheimer's disease (AD). AD risk alleles are enriched within enhancers active in myeloid cells, suggesting that microglia, the brain-resident macrophages, may play a key role in the etiology of AD. A major genetic risk factor for AD is Apolipoprotein E (APOE) genotype, with the ε4/ε4 (E4) genotype increasing risk for AD by approximately 15 fold compared to the most common ε3/ε3 (E3) genotype. However, the impact of APOE genotype on microglial function has not been thoroughly investigated. To address this, we cultured primary microglia from mice in which both alleles of the mouse Apoe gene have been humanized to encode either human APOE ε3 or APOE ε4. Relative to E3 microglia, E4 microglia exhibit altered morphology, increased endolysosomal mass, increased cytokine/chemokine production, and increased lipid and lipid droplet accumulation at baseline. These changes were accompanied by decreased translation and increased phosphorylation of eIF2ɑ and eIF2ɑ-kinases that participate in the integrated stress response, suggesting that E4 genotype leads to elevated levels of cellular stress in microglia relative to E3 genotype. Using live-cell imaging and flow cytometry, we also show that E4 microglia exhibited increased phagocytic uptake of myelin and other substrates compared to E3 microglia. While transcriptomic profiling of myelin-challenged microglia revealed a largely overlapping response profile across genotypes, differential enrichment of genes in interferon signaling, extracellular matrix and translation-related pathways was identified in E4 versus E3 microglia both at baseline and following myelin challenge. Together, our results suggest E4 genotype confers several important functional alterations to microglia even prior to myelin challenge, providing insight into the molecular and cellular mechanisms by which APOE4 may increase risk for AD.

SLAMF7 engagement superactivates macrophages in acute and chronic inflammation

Macrophages regulate protective immune responses to infectious microbes, but aberrant macrophage activation frequently drives pathological inflammation. To identify regulators of vigorous macrophage activation, we analyzed RNA-seq data from synovial macrophages and identified SLAMF7 as a receptor associated with a superactivated macrophage state in rheumatoid arthritis. We implicated IFN-γ as a key regulator of SLAMF7 expression and engaging SLAMF7 drove a strong wave of inflammatory cytokine expression. Induction of TNF-α after SLAMF7 engagement amplified inflammation through an autocrine signaling loop. We observed SLAMF7-induced gene programs not only in macrophages from rheumatoid arthritis patients but also in gut macrophages from patients with active Crohn's disease and in lung macrophages from patients with severe COVID-19. This suggests a central role for SLAMF7 in macrophage superactivation with broad implications in human disease pathology.

Human Immune System Diseasome Networks and Female Oviductal Microenvironment: New Horizons to be Discovered

Human hypofertility and infertility are two worldwide conditions experiencing nowadays an alarming increase due to a complex ensemble of events. The immune system has been suggested as one of the responsible for some of the etiopathogenic mechanisms involved in these conditions. To shed some light into the strong correlation between the reproductive and immune system, as can be inferred by the several and valuable manuscripts published to date, here we built a network using a useful bioinformatic tool (DisGeNET), in which the key genes involved in the sperm-oviduct interaction were linked. This constitutes an important event related with Human fertility since this interaction, and specially the spermatozoa, represents a not-self entity immunotolerated by the female. As a result, we discovered that some proteins involved in the sperm-oviduct interaction are implicated in several immune system diseases while, at the same time, some immune system diseases could interfere by using different pathways with the reproduction process. The data presented here could be of great importance to understand the involvement of the immune system in fertility reduction in Humans, setting the basis for potential immune therapeutic tools in the near future.

Cytokine Receptors-Regulators of Antimycobacterial Immune Response

Cytokine receptors are critical regulators of the antimycobacterial immune response, playing a key role in initiating and coordinating the recruitment and activation of immune cells during infection. They recognize and bind specific cytokines and are involved in inducing intracellular signal transduction pathways that regulate a diverse range of biological functions, including proliferation, differentiation, metabolism and cell growth. Due to mutations in cytokine receptor genes, defective signaling may contribute to increased susceptibility to mycobacteria, allowing the pathogens to avoid killing and immune surveillance. This paper provides an overview of cytokine receptors important for the innate and adaptive immune responses against mycobacteria and discusses the implications of receptor gene defects for the course of mycobacterial infection.

Selenium-Enriched Yeast Relieves Hexavalent Chromium Toxicity by Inhibiting NF-κB Signaling Pathway in Broiler Spleens

Simple Summary

Hexavalent chromium is a common environmental pollution. It has been reported that hexavalent chromium threatens the health of humans and animals, so it is necessary to develop new, effective mitigation methods. Selenium is an indispensable micronutrient recently shown to be able to resist the toxicity of heavy metals. Selenium-enriched yeast has a high content of total selenium, which has the advantages of a high absorption rate and safety. Potassium dichromate and selenium-enriched yeast were used to construct single hexavalent chromium and combined selenium/hexavalent-chromium-exposed broiler models. Additionally, the ability to relieve the hexavalent chromium toxicity of selenium along with the molecular mechanisms focusing on inflammation induced by the NF-κB signaling pathway was investigated in this study. Histopathological assessment, serum biochemical tests, oxidative stress kits, enzyme-linked immunosorbent assay, quantitative real-time PCR, and Western blotting were used to detect indicators. We found that the oxidative stress induced by hexavalent chromium triggers NF-κB pathway-driven inflammatory responses in the broiler spleen and further reduces the immune function of broilers. Selenium-enriched yeast protects the spleen from the toxicity of hexavalent chromium exposure through inhibiting the NF-κB signaling pathway.

Abstract

This study was conducted to investigate the molecular mechanisms of selenium (Se) antagonism of hexavalent chromium (Cr⁶⁺)-induced toxicity. Potassium dichromate (K₂Cr₂O₇) and selenium-enriched yeast (SeY) were used to construct the single Cr⁶⁺ and combined Se/Cr⁶⁺ exposure broiler models, and then the broilers were randomly divided into four groups (C group, Se group, Se/Cr⁶⁺ group, and Cr⁶⁺ group). After a 42-day experiment, the spleen tissues of broilers were excised and weighted. The antagonistic mechanisms of Se and Cr⁶⁺ were evaluated using histopathological assessment, serum biochemical tests, oxidative stress kits, ELISA, qPCR, and Western blotting. On the whole, there were no significant changes between the C and Se groups. The spleen organ index in the Cr⁶⁺ group was significantly decreased, but SeY increased spleen organ index to a certain extent. The levels of SOD and GSH were reduced, and the MDA content was elevated by Cr⁶⁺; however, these changes were mitigated by Se/Cr⁶⁺ exposure. Importantly, Cr⁶⁺ exposure induced a series of histopathological injuries in broiler spleen tissues, while these symptoms were significantly relieved in the Se/Cr⁶⁺group. Furthermore, Cr⁶⁺ significantly decreased the levels of T-globulin, IgA, IgM, and IgG in serum. Contrarily, dramatically more T-globulin IgA, IgM, and IgG were found in the Se/Cr⁶⁺group than in the Cr⁶⁺ group. Revealed by the results of qPCR and WB, the expressions of NF-κB, IκBα, and p-IκBα were upregulated in Cr⁶⁺ groups, while they were downregulated in Se/Cr⁶⁺ group compared to that in Cr⁶⁺ group. Besides IFN-γ and IL-2, the expressions of pro-inflammatory cytokines were significantly increased by Cr⁶⁺ exposure, but the SeY supplement relived the expression levels mediated by Cr⁶⁺ exposure. In conclusion, our findings suggest SeY has biological activity that can protect broiler spleens from immunosuppression and inflammation induced by Cr⁶⁺, and we speculate that the NF-κB signaling pathway is one of its mechanisms.