Extracellular vesicles from alveolar macrophages harboring phagocytosed methicillin-resistant Staphylococcus aureus induce necroptosis.

Methicillin-resistant Staphylococcus aureus (MRSA) infection, a major cause of hospital- and community-acquired pneumonia, still has a high mortality rate. Extracellular vesicles (EVs), as crucial mediators of intercellular communication, have a significant impact on infectious diseases. However, the role of EVs from alveolar macrophages (AMs) in MRSA pneumonia remains unclear. We report that AMs phagocytose MRSA and release more EVs in mice with MRSA pneumonia. EVs from AMs harboring phagocytosed MRSA exhibit significant proinflammatory effects and induce necroptosis by delivering tumor necrosis factor α (TNF-α) and miR-146a-5p. Mechanically, the upregulated miR-146a-5p in these EVs enhances the phosphorylation of RIPK1, RIPK3, and MLKL by targeting TNF receptor-associated factor 6 (TRAF6), thereby promoting TNF-α-induced necroptosis. The combination of a TNF-α antagonist and an miR-146a-5p antagomir effectively improves the outcomes of mice with MRSA pneumonia. Overall, we reveal the pronecrotic effect of EVs from MRSA-infected AMs and provide a promising target for the prevention and treatment of MRSA pneumonia.

Hypoxia and inflammation induce synergistic transcriptome turnover in macrophages.

Macrophages are effector immune cells that experience substantial changes to oxygenation when transiting through tissues, especially when entering tumors or infected wounds. How hypoxia alters gene expression and macrophage effector function at the post-transcriptional level remains poorly understood. Here, we use TimeLapse-seq to measure how inflammatory activation modifies the hypoxic response in primary macrophages. Nucleoside recoding sequencing allows the derivation of steady-state transcript levels, degradation rates, and transcriptional synthesis rates from the same dataset. We find that hypoxia produces distinct responses from resting and inflammatory macrophages. Hypoxia induces destabilization of mRNA transcripts, though inflammatory macrophages substantially increase mRNA degradation compared to resting macrophages. Increased RNA turnover results in the upregulation of ribosomal protein genes and downregulation of extracellular matrix components in inflammatory macrophages. Pathways regulated by mRNA decay in vitro are differentially regulated in tumor-associated macrophages implying that mixed stimuli could induce post-transcriptional regulation of macrophage function in solid tumors.

Induction cyclophosphamide with maintenance immunosuppression in high-risk myasthenia gravis: long-term follow-up and safety profile.

BACKGROUND: Patients with refractory or high-risk myasthenia gravis (MG) respond poorly to conventional immunosuppressive therapy, requiring rescue therapies and often experiencing treatment toxicity. Rescue and injectable therapies do not induce remission and require repetitive administration leading to significant constraints on patients and the healthcare system. This long-term follow-up study demonstrates cyclophosphamide as a rapidly effective and safe treatment in patients with refractory or high-risk MG. METHODS: Retrospective cohort study of MG patients treated with cyclophosphamide between January 2000 and June 2022 conducted at a quaternary neuroimmunology clinic in New South Wales, Australia. RESULTS: 31 patients were treated: mean age of 64 years; median follow-up 3.6 years (5 months to 11 years); 94% seropositive to acetylcholine receptor (AChR) antibodies and 45% had thymoma. A reduced intensity cyclophosphamide induction protocol followed by oral antiproliferative maintenance is described.Median myasthenia gravis composite scores reduced by >50% after the third cycle of cyclophosphamide. Complete cessation of prednisolone was possible in 11 patients while 20 remained on prednisolone with a median daily dose of 5 mg. Plasma exchange was ceased in 62% of patients and intravenous immunoglobulin ceased in 55%. Cyclophosphamide was generally well tolerated with mild cytopenias. There were no malignancies or cases of haemorrhagic cystitis. CONCLUSION: We describe a large cohort of high-risk MG patients treated with cyclophosphamide in a retrospective single-clinic cohort. We suggest cyclophosphamide should be considered for rapid remission induction, corticosteroid reduction and long-term freedom from recurrent injectable therapies in selected patients, typically those with AChR antibodies.

Fusobacterium nucleatum subsp. nucleatum RadD binds Siglec-7 and inhibits NK cell-mediated cancer cell killing.

Fusobacterium nucleatum is an oral commensal bacterium that can colonize extraoral tumor entities, such as colorectal cancer and breast cancer. Recent studies revealed its ability to modulate the immune response in the tumor microenvironment (TME), promoting cancer progression and metastasis. Importantly, F. nucleatum subsp. animalis was shown to bind to Siglec-7 via lipopolysaccharides, leading to a pro-inflammatory profile in human monocyte-derived dendritic cells. In this study, we show that F. nucleatum subsp. nucleatum RadD binds to Siglec-7 on NK cells, thereby inhibiting NK cell-mediated cancer cell killing. We demonstrate that this binding is dependent on arginine residue R124 in Siglec-7. Finally, we determine that this binding is independent of the known interaction of RadD with IgA. Taken together, our findings elucidate the targeting of Siglec-7 by F. nucleatum subsp. nucleatum RadD as a means to modulate the NK cell response and potentially promoting immune evasion and tumor progression.

Erythropoietin induces tumour progression and CD39 expression on immune cells in a preclinical model of triple-negative breast cancer.

The adverse effects observed in some cancer patients treated with erythropoiesis-stimulating agents such as erythropoietin (EPO) might be due to the latter's well-known immunosuppressive functions. Here, we used a mouse model of syngeneic triple-negative breast cancer to explore EPO's immunomodulatory role in a tumour setting. Our results showed that EPO treatment promotes tumour growth, exacerbates the 'immune desert', and results in a 'cold tumour'. EPO treatment changed the immune cell distribution in peripheral blood, secondary lymphoid organs, and the tumour microenvironment (TME). Our in-depth analysis showed that EPO mainly impacts CD4 T cells by accelerating their activation in the spleen and thus their subsequent exhaustion in the TME. This process is accompanied by a general elevation of CD39 expression by several immune cells (notably CD4 T cells in the tumour and spleen), which promotes an immunosuppressive TME. Lastly, we identified a highly immunosuppressive CD39+ regulatory T cell population (ICOS+, CTLA4+, Ki67+) as a potential biomarker of the risk of EPO-induced tumour progression. EPO displays pleiotropic immunosuppressive functions and enhances mammary tumour progression in mice.

Lymphotoxin ß receptor and tertiary lymphoid organs shape acute and chronic allograft rejection.

Solid organ transplantation remains the life-saving treatment for end-stage organ failure, but chronic rejection remains a major obstacle to long-term allograft outcomes and has not improved substantially. Tertiary lymphoid organs (TLO) are ectopic lymphoid structures that form under conditions of chronic inflammation, and evidence from human transplantation suggests that TLO regularly form in allografts undergoing chronic rejection. In this study, we utilized a mouse renal transplantation model and manipulation of the lymphotoxin alpha (LTα) - lymphotoxin beta receptor (LTßR) pathway, which is essential for TLO formation, to define the role of TLO in transplantation. We showed that intragraft TLO are sufficient to activate the alloimmune response and mediate graft rejection in a model where the only lymphoid organs are TLO in the allograft. When transplanted to recipients with a normal set of secondary lymphoid organs, the presence of graft TLO or LTα overexpression accelerated rejection. If the LTßR pathway was disrupted in the donor graft, TLO formation was abrogated, and graft survival prolonged. Intravital microscopy of renal TLO demonstrated that local T and B cell activation in TLOs is similar to that observed in secondary lymphoid organs. In summary, we demonstrated that immune activation in TLO contributes to local immune responses, leading to earlier allograft failure. TLO and the LTαß-LTßR pathway are therefore prime targets to limit local immune responses and prevent allograft rejection. These findings are applicable to other diseases such as autoimmunity or tumors, where either limiting or boosting local immune responses is beneficial and improves disease outcomes.

Iron capture through CD71 drives perinatal and tumor-associated Treg expansion.

Beside suppressing immune responses, regulatory T cells (Tregs) maintain tissue homeostasis and control systemic metabolism. Whether iron is involved in Treg-mediated tolerance is completely unknown. Here, we showed that the transferrin receptor CD71 was upregulated on activated Tregs infiltrating human liver cancer. Mice with a Treg-restricted CD71 deficiency spontaneously developed a scurfy-like disease, caused by impaired perinatal Treg expansion. CD71-null Tregs displayed decreased proliferation and tissue-Treg signature loss. In perinatal life, CD71 deficiency in Tregs triggered hepatic iron overload response, characterized by increased hepcidin transcription and iron accumulation in macrophages. Lower bacterial diversity, and reduction of beneficial species, were detected in the fecal microbiota of CD71 conditional knock-out neonates. Our findings indicate that CD71-mediated iron absorption is required for Treg perinatal expansion and related to systemic iron homeostasis and bacterial gut colonization. Therefore, we hypothesize that Tregs establish nutritional tolerance through competition for iron during bacterial colonization after birth.

Evaluation of soluble co-inhibitors and co-stimulators levels of the immune response in gastric cancer.

BACKGROUND: Co-inhibitor and co-stimulator mediators trigger actions that result in immunological homeostasis and are being evaluated as potential therapeutic targets in gastric cancer (GC). OBJECTIVE: To evaluate the soluble levels of sPD-1, sPD-L1, sPD-L2, sTIM-3, sGal9, sGITR, and sGITRL in GC patients. METHODS: The cross-sectional study was carried out at the Hospital de Cancer de Pernambuco, Brazil between 2017 and 2018. A total of 74 GC patients and 30 healthy controls were included. RESULTS: Low levels of sPD1 (p = 0.0179), sPDL2 (p = 0.0003), and sGal9 (p < 0.0001), and higher levels of sPDL1 (p = 0.004), sTIM-3 (p = 0.0072), sGITR (p = 0.0179), and sGITRL (p = 0.0055) compared to the control group. High sPD-1, sTIM-3, and sGal9 levels in stage IV compared I/II and III (p < 0.05). High sPDL1, sGal9, and sGITRL levels in esophagogastric junction compared to body and Pylorus/Antrum groups (p < 0.05). No significant differences were observed in sPD1, sPDL1, sPDL2, sTIM3, sGal9, sGITR, and sGITRL levels between the intestinal, diffuse, and mixed GC groups. Low sGITR levels in GC patients who died within the first 24 months compared to the who survived (p = 0.0332). CONCLUSIONS: There is an association of sPD1, sTIM-3, and sGal9 with disease progression and sGITR with death, these mediators may be potential prognostic biomarkers in GC.

Regulation of IFN-γ production by ZFP36L2 in T cells is time-dependent.

CD8+ T cells kill target cells by releasing cytotoxic molecules and proinflammatory cytokines, such as TNF and IFN-γ. The magnitude and duration of cytokine production are defined by posttranscriptional regulation, and critical regulator herein are RNA-binding proteins (RBPs). Although the functional importance of RBPs in regulating cytokine production is established, the kinetics and mode of action through which RBPs control cytokine production are not well understood. Previously, we showed that the RBP ZFP36L2 blocks the translation of preformed cytokine encoding mRNA in quiescent memory T cells. Here, we uncover that ZFP36L2 regulates cytokine production in a time-dependent manner. T cell-specific deletion of ZFP36L2 (CD4-cre) had no effect on T-cell development or cytokine production during early time points (2-6 h) of T-cell activation. In contrast, ZFP36L2 specifically dampened the production of IFN-γ during prolonged T-cell activation (20-48 h). ZFP36L2 deficiency also resulted in increased production of IFN-γ production in tumor-infiltrating T cells that are chronically exposed to antigens. Mechanistically, ZFP36L2 regulates IFN-γ production at late time points of activation by destabilizing Ifng mRNA in an AU-rich element-dependent manner. Together, our results reveal that ZFP36L2 employs different regulatory nodules in effector and memory T cells to regulate cytokine production.

Preexisting maternal immunity to AAV but not Cas9 impairs in utero gene editing in mice.

In utero gene editing (IUGE) is a potential treatment for inherited diseases that cause pathology before or soon after birth. Preexisting immunity to adeno-associated virus (AAV) vectors and Cas9 endonuclease may limit postnatal gene editing. The tolerogenic fetal immune system minimizes a fetal immune barrier to IUGE. However, the ability of maternal immunity to limit fetal gene editing remains a question. We investigated whether preexisting maternal immunity to AAV or Cas9 impairs IUGE. Using a combination of fluorescent reporter mice and a murine model of a metabolic liver disease, we demonstrated that maternal anti-AAV IgG antibodies were efficiently transferred from dam to fetus and impaired IUGE in a maternal titer-dependent fashion. By contrast, maternal cellular immunity was inefficiently transferred to the fetus, and neither maternal cellular nor humoral immunity to Cas9 impaired IUGE. Using human umbilical cord and maternal blood samples collected from mid- to late-gestation pregnancies, we demonstrated that maternal-fetal transmission of anti-AAV IgG was inefficient in midgestation compared with term, suggesting that the maternal immune barrier to clinical IUGE would be less relevant at midgestation. These findings support immunologic advantages for IUGE and inform maternal preprocedural testing protocols and exclusion criteria for future clinical trials.

Allergies and risk of head and neck cancer: a case-control study.

Although the relationship between allergies and cancer has been investigated extensively, the role of allergies in head and neck cancer (HNC) appears less consistent. It is unclear whether allergies can independently influence the risk of HNC in the presence of substantial environmental risk factors, including consumption of alcohol, betel quid, and cigarettes. This study aims to find this association. We examined the relationship between allergies and HNC risk in a hospital-based case-control study with 300 cases and 375 matched controls. Logistic regression models were used to estimate odds ratios (OR) and 95% confidence intervals, controlling for age, sex, tobacco smoking and opium usage history, alcohol consumption, and socioeconomic status. Our study showed a significant reduction in the risk of HNC associated with allergy symptoms after adjusting for confounders. The risk of HNC was greatly reduced among those with any type of allergy (OR 0.42, 95% CI 0.28, 0.65). The ORs were considerably reduced by 58-88% for different kinds of allergies. The risk of HNC reduction was higher in allergic women than in allergic men (71% vs. 49%). Allergies play an influential role in the risk of HNC development. Future studies investigating immune biomarkers, including cytokine profiles and genetic polymorphisms, are necessary to further delineate the relationship between allergies and HNC. Understanding the relationship between allergies and HNC may help to devise effective strategies to reduce and treat HNC.

ER-to-lysosome Ca2+ refilling followed by K+ efflux-coupled store-operated Ca2+ entry in inflammasome activation and metabolic inflammation.

We studied lysosomal Ca2+ in inflammasome. Lipopolysaccharide (LPS) + palmitic acid (PA) decreased lysosomal Ca2+ ([Ca2+]Lys) and increased [Ca2+]i through mitochondrial ROS, which was suppressed in Trpm2-KO macrophages. Inflammasome activation and metabolic inflammation in adipose tissue of high-fat diet (HFD)-fed mice were ameliorated by Trpm2 KO. ER→lysosome Ca2+ refilling occurred after lysosomal Ca2+ release whose blockade attenuated LPS + PA-induced inflammasome. Subsequently, store-operated Ca2+entry (SOCE) was activated whose inhibition suppressed inflammasome. SOCE was coupled with K+ efflux whose inhibition reduced ER Ca2+ content ([Ca2+]ER) and impaired [Ca2+]Lys recovery. LPS + PA activated KCa3.1 channel, a Ca2+-activated K+ channel. Inhibitors of KCa3.1 channel or Kcnn4 KO reduced [Ca2+]ER, attenuated increase of [Ca2+]i or inflammasome activation by LPS + PA, and ameliorated HFD-induced inflammasome or metabolic inflammation. Lysosomal Ca2+ release induced delayed JNK and ASC phosphorylation through CAMKII-ASK1. These results suggest a novel role of lysosomal Ca2+ release sustained by ER→lysosome Ca2+ refilling and K+ efflux through KCa3.1 channel in inflammasome activation and metabolic inflammation.

Monoclonal antibody biosimilars for cancer treatment.

Monoclonal antibodies are important cancer medicines. The European Medicines Agency (EMA) approved 48 and the Food and Drug Administration (FDA) 56 anticancer monoclonal antibody-based therapies. Their high prices burden healthcare systems and hamper global drug access. Biosimilars could retain costs and expand the availability of monoclonal antibodies. In Europe, five rituximab biosimilars, six trastuzumab biosimilars, and eight bevacizumab biosimilars are available as anti-cancer drugs. To gain insight into the biosimilar landscape for cancer treatment, we performed a literature search and analysis. In this review, we summarize cancer monoclonal antibodies' properties crucial for the desired pharmacology and point out sources of variability. The analytical assessment of all EMA-approved bevacizumab biosimilars is highlighted to illustrate this variability. The global landscape of investigational and approved biosimilars is mapped, and the challenges for access to cancer biosimilars are identified.

A single gene determines allorecognition in hydrozoan jellyfish Cladonema radiatum inbred lines.

Allorecognition-the ability of an organism to discriminate between self and nonself-is crucial to colonial marine animals to avoid invasion by other individuals in the same habitat. The cnidarian hydroid Hydractinia has long been a major research model in studying invertebrate allorecognition, establishing a rich knowledge foundation. In this study, we introduce a new cnidarian model Cladonema radiatum (C. radiatum). C. radiatum is a hydroid jellyfish which also forms polyp colonies interconnected with stolons. Allorecognition responses-fusion or regression of stolons-are observed when stolons encounter each other. By transmission electron microscopy, we observe rapid tissue remodeling contributing to gastrovascular system connection in fusion. Meanwhile, rejection responses are regulated by reconstruction of the chitinous exoskeleton perisarc, and induction of necrotic and autophagic cellular responses at cells in contact with the opponent. Genetic analysis identifies allorecognition genes: six Alr genes located on the putative allorecognition complex and four immunoglobulin superfamily genes on a separate genome region. C. radiatum allorecognition genes show notable conservation with the Hydractinia Alr family. Remarkedly, stolon encounter assays of inbred lines reveal that genotypes of Alr1 solely determine allorecognition outcomes in C. radiatum.

Hepatocyte-derived FGL1 accelerates liver metastasis and tumor growth by inhibiting CD8+ T and NK cells.

Fibrinogen-like protein 1 (FGL1) contributes to the proliferation and metabolism of hepatocytes; however, as a major ligand of the immune checkpoint, its role in the liver regional immune microenvironment is poorly understood. Hepatocytes specifically and highly expressed FGL1 under normal physiological conditions. Increases in hepatic CD8+ T and NK cell numbers and functions were found in Fgl1-deficient (Fgl1-/-) mice, but not in the spleen or lymph node, similar to findings in anti-FGL1 mAb-treated wild-type mice. Furthermore, Fgl1 deficiency or anti-FGL1 mAb blockade restrained liver metastasis and slowed the growth of orthotopic tumors, with significantly prolonged survival of tumor-bearing mice. Tumor-infiltrating hepatic CD8+ T and NK cells upregulated the expression of lymphocyte activation gene-3 (LAG-3) and exhibited stronger antitumor activities after anti-FGL1 treatment. The antitumor efficacy of FGL1 blockade depended on cytotoxic T lymphocytes and NK cells, demonstrated by using a cell-deficient mouse model and cell transfer in vivo. In vitro, FGL1 directly inhibited hepatic T and NK cells related to the receptor LAG-3. In conclusion, hepatocyte-derived FGL1 played critical immunoregulatory roles in the liver and contributed to liver metastasis and tumor growth by inhibiting CD8+ T and NK cell functions via the receptor LAG-3, providing a new strategy for liver cancer immunotherapy.

Decoding immune-related gene-signatures in colorectal neoplasia.

Background: Colorectal cancer (CRC) is a significant health issue, with notable incidence rates in Norway. The immune response plays a dual role in CRC, offering both protective effects and promoting tumor growth. This research aims to provide a detailed screening of immune-related genes and identify specific genes in CRC and adenomatous polyps within the Norwegian population, potentially serving as detection biomarkers. Methods: The study involved 69 patients (228 biopsies) undergoing colonoscopy, divided into CRC, adenomatous polyps, and control groups. We examined the expression of 579 immune genes through nCounter analysis emphasizing differential expression in tumor versus adjacent non-tumorous tissue and performed quantitative reverse transcription polymerase chain reaction (RT-qPCR) across patient categories. Results: Key findings include the elevated expression of CXCL1, CXCL2, IL1B, IL6, CXCL8 (IL8), PTGS2, and SPP1 in CRC tissues. Additionally, CXCL1, CXCL2, IL6, CXCL8, and PTGS2 showed significant expression changes in adenomatous polyps, suggesting their early involvement in carcinogenesis. Conclusions: This study uncovers a distinctive immunological signature in colorectal neoplasia among Norwegians, highlighting CXCL1, CXCL2, IL1B, IL6, CXCL8, PTGS2, and SPP1 as potential CRC biomarkers. These findings warrant further research to confirm their role and explore their utility in non-invasive screening strategies.

Generation of immune cells from induced pluripotent stem cells (iPSCs): Their potential for adoptive cell therapy.

Advances in human stem cell technologies enable induced pluripotent stem cells (iPSCs) to be explored as potent candidates for treating various diseases, such as malignancies, autoimmunity, immunodeficiencies, and allergic reactions. iPSCs with infinite self-renewal ability can be derived from different types of somatic cells without the ethical issues associated with embryonic stem cells. To date, numerous cell types, including various immune cell subsets [CD4+ and CD8+ T cells, gamma delta T (γδ T) cells, regulatory T cells, dendritic cells, natural killer cells, macrophages, and neutrophils] have successfully been generated from iPSCs paving the way for effective adoptive cell transfer therapy, drug development, and disease modeling. Herein, we review various iPSC-derived immune cells and their possible application in immunotherapy.

Glutamine metabolic competition drives immunosuppressive reprogramming of intratumour GPR109A+ myeloid cells to promote liver cancer progression.

OBJECTIVE: The metabolic characteristics of liver cancer drive considerable hurdles to immune cells function and cancer immunotherapy. However, how metabolic reprograming in the tumour microenvironment impairs the antitumour immune response remains unclear. DESIGN: Human samples and multiple murine models were employed to evaluate the correlation between GPR109A and liver cancer progression. GPR109A knockout mice, immune cells depletion and primary cell coculture models were used to determine the regulation of GPR109A on tumour microenvironment and identify the underlying mechanism responsible for the formation of intratumour GPR109A+myeloid cells. RESULTS: We demonstrate that glutamine shortage in liver cancer tumour microenvironment drives an immunosuppressive GPR109A+myeloid cells infiltration, leading to the evasion of immune surveillance. Blockade of GPR109A decreases G-MDSCs and M2-like TAMs abundance to trigger the antitumour responses of CD8+ T cells and further improves the immunotherapy efficacy against liver cancer. Mechanistically, tumour cells and tumour-infiltrated myeloid cells compete for glutamine uptake via the transporter SLC1A5 to control antitumour immunity, which disrupts the endoplasmic reticulum (ER) homoeostasis and induces unfolded protein response of myeloid cells to promote GPR109A expression through IRE1α/XBP1 pathway. The restriction of glutamine uptake in liver cancer cells, as well as the blockade of IRE1α/XBP1 signalling or glutamine supplementation, can eliminate the immunosuppressive effects of GPR109A+ myeloid cells and slow down tumour progression. CONCLUSION: Our findings identify the immunometabolic crosstalk between liver cancer cells and myeloid cells facilitates tumour progression via a glutamine metabolism/ER stress/GPR109A axis, suggesting that GPR109A can be exploited as an immunometabolic checkpoint and putative target for cancer treatment.

Organoids as regenerative medicine for inflammatory bowel disease.

Inflammatory bowel disease (IBD) is a chronic disorder with an increasing global prevalence. Managing disease activity relies on various pharmacological options. However, the effectiveness of current therapeutics is limited and not universally applicable to all patients and circumstances. Consequently, developing new management strategies is necessary. Recent advances in endoscopically obtained intestinal biopsy specimens have highlighted the potential of intestinal epithelial organoid transplantation as a novel therapeutic approach. Experimental studies using murine and human organoid transplantations have shown promising outcomes, including tissue regeneration and functional recovery. Human trials with organoid therapy have commenced; thus, this article provides readers with insights into the necessity and potential of intestinal organoid transplantation as a new regenerative therapeutic option in clinical settings and explores its associated challenges.