Swiprosin-1 deficiency impairs macrophage immune response of septic mice

EFHD2 regulates T cell receptor signaling and modulates T helper cell activation in early sepsis

EFHD2 (EF-hand domain family, member D2) has been identified as a calcium-binding protein with immunomodulatory effects. In this study, we characterized the phenotype of Efhd2-deficient mice in sepsis and examined the biological functions of EFHD2 in peripheral T cell activation and T helper (Th) cell differentiation. Increased levels of EFHD2 expression accompanied peripheral CD4+ T cell activation in the early stages of sepsis. Transcriptomic analysis indicated that immune response activation was impaired in Efhd2-deficient CD4+ T cells. Further, Efhd2-deficient CD4+ T cells isolated from the spleen of septic mice showed impaired T cell receptor (TCR)-induced Th differentiation, especially Th1 and Th17 differentiation. In vitro data also showed that Efhd2-deficient CD4+ T cells exhibit impaired Th1 and Th17 differentiation. In the CD4+ T cells and macrophages co-culture model for antigen presentation, the deficiency of Efhd2 in CD4+ T cells resulted in impaired formation of immunological synapses. In addition, Efhd2-deficient CD4+ T cells exhibited reduced levels of phospho-LCK and phospho-ZAP70, and downstream transcription factors including Nfat, Nfκb and Nur77 following TCR engagement. In summary, EFHD2 may promote TCR-mediated T cell activation subsequent Th1 and Th17 differentiation in the early stages of sepsis by regulating the intensity of TCR complex formation.

Innate immune activation restricts priming and protective efficacy of the radiation-attenuated PfSPZ malaria vaccine

A systems analysis was conducted to determine the potential molecular mechanisms underlying differential immunogenicity and protective efficacy results of a clinical trial of the radiation-attenuated whole-sporozoite PfSPZ vaccine in African infants. Innate immune activation and myeloid signatures at prevaccination baseline correlated with protection from P. falciparum parasitemia in placebo controls. These same signatures were associated with susceptibility to parasitemia among infants who received the highest and most protective PfSPZ vaccine dose. Machine learning identified spliceosome, proteosome, and resting DC signatures as prevaccination features predictive of protection after highest-dose PfSPZ vaccination, whereas baseline circumsporozoite protein-specific (CSP-specific) IgG predicted nonprotection. Prevaccination innate inflammatory and myeloid signatures were associated with higher sporozoite-specific IgG Ab response but undetectable PfSPZ-specific CD8+ T cell responses after vaccination. Consistent with these human data, innate stimulation in vivo conferred protection against infection by sporozoite injection in malaria-naive mice while diminishing the CD8+ T cell response to radiation-attenuated sporozoites. These data suggest a dichotomous role of innate stimulation for malaria protection and induction of protective immunity by whole-sporozoite malaria vaccines. The uncoupling of vaccine-induced protective immunity achieved by Abs from more protective CD8+ T cell responses suggests that PfSPZ vaccine efficacy in malaria-endemic settings may be constrained by opposing antigen presentation pathways.

Targeting EFHD2 Inhibits Interferon-γ Signaling and Ameliorates Non-Alcoholic Steatohepatitis

BACKGROUND & AIMS

The precise pathomechanisms underlying the development of nonalcoholic steatohepatitis (NASH, also known as metabolic dysfunction-associated steatohepatitis [MASH]) remain incompletely understood. This study investigates the potential role of EF-hand domain family member D2 (EFHD2), a novel molecule specific to immune cells, in NASH pathogenesis.

METHODS

Hepatic EFHD2 expression was characterized in NASH patients and two diet-induced NASH mouse models. Single-cell RNA-sequencing (scRNA-seq) and double-immunohistochemistry were employed to explore EFHD2 expression patterns in NASH livers. The effects of global and myeloid-specific EFHD2 deletion on NASH and NASH-related hepatocellular carcinoma (HCC) were assessed. Molecular mechanisms underlying EFHD2 function were investigated, along with its potential as a therapeutic target by chemical and genetic means.

RESULTS

EFHD2 expression was significantly elevated in liver tissue macrophages/monocytes in both NASH patients and mice. Deletion of EFHD2, either globally or specifically in myeloid cells, improved hepatic steatosis, reduced immune cell infiltration, inhibited lipid peroxidation-induced ferroptosis, and attenuated fibrosis in NASH. Additionally, it hindered the development of NASH-related HCC. Specifically, deletion of myeloid EFHD2 prevented the replacement of TIM4+ resident Kupffer cells by infiltrated monocytes and reversed the decreases in patrolling monocytes and CD4+/CD8+ T cell ratio in NASH. Mechanistically, our investigation revealed that EFHD2 in myeloid cells interacts with cytosolic YWHAZ (14-3-3ζ), facilitating the translocation of interferon-γ receptor-2 (IFNγR2) onto the plasma membrane. This interaction mediates IFNγ signaling, which triggers immune and inflammatory responses in macrophages during NASH. Finally, a developed stapled α-helical peptide targeting EFHD2 demonstrated its efficacy in protecting against NASH pathology in mice.

CONCLUSION

Our study reveals a pivotal immunomodulatory and inflammatory role of EFHD2 in NASH, underscoring EFHD2 as a promising druggable target for NASH treatment.

IMPACT AND IMPLICATIONS

Nonalcoholic steatohepatitis (NASH) represents an advanced stage of non-alcoholic fatty liver disease (NAFLD); however, not all NAFLD patients progress to NASH. A key challenge is identifying the factors triggering inflammation, which propels the transition from simple fatty liver to NASH. Our research pinpointed EFHD2 as a pivotal driver of NASH, orchestrating the over-activation of IFNγ signaling within the liver during NASH progression. A stapled peptide designed to target EFHD2 exhibited therapeutic promise in NASH mice. These findings suggest EFHD2 as a promising target for drug development aimed at NASH treatment.

The functions of EF-hand proteins from host and zoonotic pathogens

EF-hand proteins not only regulate biological processes, but also influence immunity and infection. In this review, we summarize EF-hand proteins' functions in host and zoonotic pathogens, with details in structures, Ca2+ affinity, downstream targets and functional mechanisms. Studies entitled as EF-hand-related but with less solid features were also discussed. We believe it could raise cautions and facilitate proper research strategy for researchers.

Clinical characterization of EFHD2 (swiprosin-1) in Glioma-associated macrophages and its role in regulation of immunosuppression

Glioblastoma has been extensively studied due to its high mortality and short survival. The evolution mechanism of tumor-associated macrophages (TAMs) to Glioma-associated microglia and macrophages (GAMs) in the tumor microenvironment (TME) remains to be elucidated. The tumor cell-to-cell interaction patterns have not been well defined yet. The EF-Hand Domain Family Member D2 (EFHD2) has been reported to be differentially expressed as an immunomodulatory molecule in a variety of cancers. But large-scale clinical data from multiple ethnic communities have not been used to investigate the role of EFHD2 in glioma. RNA-seq data from 313 or 657 glioma patients from the Chinese Glioma Genome Atlas (CGGA) database and 603 glioma patients from the Cancer Genome Atlas (TCGA) database were analyzed retrospectively. Cell localization was performed using single-cell sequencing data from the CGGA database and the GSE131928 dataset. Mouse glioma cell lines and primary macrophages isolated from Efhd2 knockout mice were co-cultured to validate the immunomodulatory effects of EFHD2 on macrophages and the remodeling of TME of glioblastoma. EFHD2 is enriched in high-grade gliomas, isocitrate dehydrogenase wild-type, and 1p/19q non-co-deficient gliomas. It is a potential biomarker of glioma-proneuronal subtypes and an independent prognostic factor for overall survival in patients with malignant glioblastoma. EFHD2 regulates the monocyte-macrophage system function and positively correlates with immunosuppressive checkpoints. Further experimental data demonstrates that Efhd2 influences the polarization state of GAMs and inhibits the secretion of TGF-β1. In vitro experiments have revealed that macrophages lacking Efhd2 suppress the vitality of two glioma cell lines and decelerate the growth of glioma xenografts. In conclusion, EFHD2 promises to be a key target for TME-related immunotherapy.

BNP protects against diabetic cardiomyopathy by promoting Opa1-mediated mitochondrial fusion via activating the PKG-STAT3 pathway

Brain natriuretic peptide (BNP) belongs to the family of natriuretic peptides, which are responsible for a wide range of actions. Diabetic cardiomyopathy (DCM) is often associated with increased BNP levels. This present research intends to explore the role of BNP in the development of DCM and the underlying mechanisms. Diabetes was induced in mice using streptozotocin (STZ). Primary neonatal cardiomyocytes were treated with high glucose. It was found that the levels of plasma BNP started to increase at 8 weeks after diabetes, which preceded the development of DCM. Addition of exogenous BNP promoted Opa1-mediated mitochondrial fusion, inhibited mitochondrial oxidative stress, preserved mitochondrial respiratory capacity and prevented the development of DCM, while knockdown of endogenous BNP exacerbated mitochondrial dysfunction and accelerated DCM. Opa1 knockdown attenuated the aforementioned protective action of BNP both in vivo and in vitro. BNP-induced mitochondrial fusion requires the activation of STAT3, which facilitated Opa1 transcription by binding to its promoter regions. PKG, a crucial signaling biomolecule in the BNP signaling pathway, interacted with STAT3 and induced its activation. Knockdown of NPRA (the receptor of BNP) or PKG blunted the promoting effect of BNP on STAT3 phosphorylation and Opa1-mediated mitochondrial fusion. The results of this study demonstrate for the first time that there is a rise in BNP during the early stages of DCM as a compensatory protection mechanism. BNP is a novel mitochondrial fusion activator in protecting against hyperglycemia-induced mitochondrial oxidative injury and DCM through the activation of NPRA-PKG-STAT3-Opa1 signaling pathway.

Swip-1 promotes exocytosis of glue granules in the exocrine Drosophila salivary gland

Exocytosis is a fundamental cellular process by which cells secrete cargos from their apical membrane into the extracellular lumen. Cargo release proceeds in sequential steps that depend on coordinated assembly and organization of an actin cytoskeletal network. Here, we identified the conserved actin-crosslinking protein Swip-1 as a novel regulator controlling exocytosis of glue granules in the Drosophila salivary gland. Real-time imaging revealed that Swip-1 is simultaneously recruited with F-actin onto secreting granules in proximity to the apical membrane. We observed that Swip-1 is rapidly cleared at the point of secretory vesicle fusion and colocalizes with actomyosin network around the fused vesicles. Loss of Swip-1 function impairs secretory cargo expulsion, resulting in strongly delayed secretion. Thus, our results uncover a novel role of Swip-1 in secretory vesicle compression and expulsion of cargo during regulated exocytosis. Remarkably, this function neither requires Ca2+ binding nor dimerization of Swip-1. Our data rather suggest that Swip-1 regulates actomyosin activity upstream of Rho-GTPase signaling to drive proper vesicle membrane crumpling and expulsion of cargo.

Calcium bursts allow rapid reorganization of EFhD2/Swip-1 cross-linked actin networks in epithelial wound closure

Changes in cell morphology require the dynamic remodeling of the actin cytoskeleton. Calcium fluxes have been suggested as an important signal to rapidly relay information to the actin cytoskeleton, but the underlying mechanisms remain poorly understood. Here, we identify the EF-hand domain containing protein EFhD2/Swip-1 as a conserved lamellipodial protein strongly upregulated in Drosophila macrophages at the onset of metamorphosis when macrophage behavior shifts from quiescent to migratory state. Loss- and gain-of-function analysis confirm a critical function of EFhD2/Swip-1 in lamellipodial cell migration in fly and mouse melanoma cells. Contrary to previous assumptions, TIRF-analyses unambiguously demonstrate that EFhD2/Swip-1 proteins efficiently cross-link actin filaments in a calcium-dependent manner. Using a single-cell wounding model, we show that EFhD2/Swip-1 promotes wound closure in a calcium-dependent manner. Mechanistically, our data suggest that transient calcium bursts reduce EFhD2/Swip-1 cross-linking activity and thereby promote rapid reorganization of existing actin networks to drive epithelial wound closure.

Role of Swiprosin-1/EFHD2 as a biomarker in the development of chronic diseases

Swiprosin-1 or EFHD2, is a Ca²⁺ binding actin protein and its expression has been shown to be distinct in various cell types. The expression of swiprosin-1 is upregulated during the activation of immune cells, epithelial and endothelial cells. The expression of swiprosin-1 is regulated by diverse signaling pathways that are contingent upon the specific type of cells. The aim of this review is to summarize and provide an overview of the role of swiprosin-1 in pathophysiological conditions of cancers, cardiovascular diseases, diabetic nephropathy, neuropsychiatric diseases, and in the process of inflammation, immune response, and inflammatory diseases. Novel approaches for the targeting of swiprosin-1 as a biomarker in the early detection and prevention of various development of chronic diseases are also explored.

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

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

Swiprosin-1 deficiency in macrophages alleviated atherogenesis

Macrophages play a vital role in the development of atherosclerosis. Previously, we have found that swiprosin-1 was abundantly expressed in macrophages. Here, we investigated the role of swiprosin-1 expressed in macrophages in atherogenesis. Bone marrow transplantation was performed from swiprosin-1-knockout (Swp-/-) mice and age-matched ApoE-/- mice. Atherosclerotic lesion, serum lipid, and interleukin-β (IL-β) levels were detected. In vitro, the peritoneal macrophages isolated from Swp-/- and wild-type mice were stimulated with oxidized low-density lipoprotein (ox-LDL) and the macrophage of foam degree, cellular lipid content, apoptosis, inflammatory factor, migration, and autophagy were determined. Our results showed that swiprosin-1 was mainly expressed in macrophages of atherosclerotic plaques in aorta from ApoE-/- mice fed with high-cholesterol diet (HCD). The expression of swiprosin-1 in the foaming of RAW264.7 macrophages gradually increased with the increase of the concentration and time stimulated with ox-LDL. Atherosclerotic plaques, accumulation of macrophages, collagen content, serum total cholesterol, LDL, and IL-β levels were decreased in Swp-/- → ApoE-/- mice compared with Swp+/+ → ApoE-/- mice fed with HCD for 16 weeks. The macrophage foam cell formation and cellular cholesterol accumulation were reduced, while the lipid uptake and efflux increased in macrophages isolated from Swp-/- compared to wild-type mice treated with ox-LDL. Swiprosin-1 deficiency in macrophages could inhibit apoptosis, inflammation, migration, and promote autophagy. Taken together, our results demonstrated that swiprosin-1 deficiency in macrophages could alleviate the development and progression of AS. The role of swiprosin-1 may provide a promising new target for ameliorating AS.

Cargo-specific recruitment in clathrin- and dynamin-independent endocytosis

Spatially controlled, cargo-specific endocytosis is essential for development, tissue homeostasis and cancer invasion. Unlike cargo-specific clathrin-mediated endocytosis, the clathrin- and dynamin-independent endocytic pathway (CLIC-GEEC, CG pathway) is considered a bulk internalization route for the fluid phase, glycosylated membrane proteins and lipids. While the core molecular players of CG-endocytosis have been recently defined, evidence of cargo-specific adaptors or selective uptake of proteins for the pathway are lacking. Here we identify the actin-binding protein Swiprosin-1 (Swip1, EFHD2) as a cargo-specific adaptor for CG-endocytosis. Swip1 couples active Rab21-associated integrins with key components of the CG-endocytic machinery-Arf1, IRSp53 and actin-and is critical for integrin endocytosis. Through this function, Swip1 supports integrin-dependent cancer-cell migration and invasion, and is a negative prognostic marker in breast cancer. Our results demonstrate a previously unknown cargo selectivity for the CG pathway and a role for specific adaptors in recruitment into this endocytic route.

B Cell Speed and B-FDC Contacts in Germinal Centers Determine Plasma Cell Output via Swiprosin-1/EFhd2

Plasma cells secreting affinity-matured antibodies develop in germinal centers (GCs), where B cells migrate persistently and directionally over defined periods of time. How modes of GC B cell migration influence plasma cell development remained unclear. Through genetic deletion of the F-actin bundling protein Swiprosin-1/EF-hand domain family member 2 (EFhd2) and by two-photon microscopy, we show that EFhd2 restrains B cell speed in GCs and hapten-specific plasma cell output. Modeling the GC reaction reveals that increasing GC B cell speed promotes plasma cell generation. Lack of EFhd2 also reduces contacts of GC B cells with follicular dendritic cells in vivo. Computational modeling uncovers that both GC output and antibody affinity depend quantitatively on contacts of GC B cells with follicular dendritic cells when B cells migrate more persistently. Collectively, our data explain how GC B cells integrate speed and persistence of cell migration with B cell receptor affinity.

Schisandrin C attenuates renal damage in diabetic nephropathy by regulating macrophage polarization

This study aimed to investigate the protective effects of Schisandrin C during diabetic nephropathy (DN) treatment. After DN induction, mice were treated with Schisandrin C, and diabetic metabolic parameters and renal function-associated factors were measured. Renal structural damage was evaluated by hematoxylin and eosin (HE) and Masson's trichrome staining. Macrophage polarization and macrophage-mediated inflammatory factors were detected in the kidneys by immunohistochemistry (IHC) and enzyme-linked immunosorbent assay (ELISA), respectively. The Swiprosin-1/interferon (IFN)-γ-Rβ pathway was evaluated by western blot (WB) analysis. The preliminary effects of Schisandrin C in high-glucose-stimulated macrophages from DN mice were verified by flow cytometry, ELISA, and WB analyses. These results indicated that Schisandrin C significantly regulated physiological parameters in DN. Renal structural damage was mitigated by Schisandrin C. In Schisandrin-C-treated groups, the expression levels of CD86, tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1β decreased, whereas CD206, IL-10, and transforming growth factor (TGF)-β expression levels increased. In vitro experiments indicated that among CD86⁺ cells, TNF-α, IL-6, and IL-1β expression levels significantly decreased, whereas among CD206⁺ cells, IL-10 and TGF-β expression increased following Schisandrin-C-treatment. Finally, Schisandrin C inhibited the expression of Swiprosin-1, IFN-γ-Rβ, phospho-Janus kinase 2 (p-JAK2), phospho-signal transducer and activator of transcription 1 (p-STAT1), and p-STAT3, in both DN model mice and high-glucose-stimulated RAW264.7 cells. The present study indicated a novel use for Schisandrin C to suppress DN progression, by promoting M1 to M2 macrophage polarization. Schisandrin C exerted protective effects against DN by regulating the polarization-dependent Swiprosin-1/IFN-γ-Rβ signaling pathway in macrophages.

Drug repurposing of anti-infective clinical drugs: Discovery of two potential anti-cytokine storm agents

Coronavirus Disease 2019 (COVID-19) caused by Severe Acute Respiratory Syndrome Coronavirus -2 (SARS-CoV-2) has been widely spread in the world with a high mortality. Cytokine storm syndrome (CSS) and acute lung injury caused by SARS-CoV-2 infection severely threaten the patients. With the purpose to find effective and low-toxic drugs to mitigate CSS, entecavir and imipenem were identified to reduce TNF-α using a LPS-induced macrophage model from the anti-infective drug library. Entecavir and imipenem efficiently suppressed the release of inflammatory cytokines by partly intervention of NF-κB activity. The acute lung injury was also alleviated and the survival time was prolonged in mice. In addition, entecavir and imipenem inhibited the release of TNF-α and IL-10 in human peripheral blood mononuclear cells (hPBMCs). Collectively, we proposed that entecavir and imipenem might be candidates for the treatment of CSS.

Berberine functions as a negative regulator in lipopolysaccharide -induced sepsis by suppressing NF-κB and IL-6 mediated STAT3 activation

Sepsis is a deadly complication raised by bacterial pathogens-induced dysregulated innate inflammatory response. Thus, anti-inflammatory is a potential therapeutic treatment for septic patients. Numerous evidence exhibited that berberine possesses potent anti-inflammatory, anti-apoptotic and anti-oxidative activities. However, the effect of berberine on sepsis is not fully understood. The anti-inflammatory effect of berberine was evaluated using lipopolysaccharide (LPS)-induced macrophages differentiation model in vitro and using LPS/D-galactosamine-challenged septic mice model in vivo. The secreted protein levels were determined by ELISA assay. The multiple targets mRNA and protein levels were measured by quantitative RT-PCR and western blot assay, respectively. Our study demonstrated that administration of berberine significantly attenuated lung tissue injury, and potently increased the survival rate of septic mice by modulating excessive inflammatory response with negligible side-effects. We further found that berberine inhibited the expression of tumor necrosis factor (TNF)-α, interleukin-(IL)-1β and IL-6 via suppressing nuclear factor kappa B subunit 1 (NF-κB) signaling activation. Our study strongly supported the concept that berberine may serve as a single drug or a promising adjuvant that can be used in conjunction with other medications for the treatment of septic patients.

EFHD2 contributes to non-small cell lung cancer cisplatin resistance by the activation of NOX4-ROS-ABCC1 axis

Recurrence and metastasis remain the major cause of cancer mortality. Even for early-stage lung cancer, adjuvant chemotherapy yields merely slight increase to patient survival. EF-hand domain-containing protein D2 (EFHD2) has recently been implicated in recurrence of patients with stage I lung adenocarcinoma. In this study, we investigated the correlation between EFHD2 and chemoresistance in non-small cell lung cancer (NSCLC). High expression of EFHD2 was significantly associated with poor overall survival of NSCLC patients with chemotherapy in in silica analysis. Ectopic EFHD2 overexpression increased cisplatin resistance, whereas EFHD2 knockdown improved chemoresponse. Mechanistically, EFHD2 induced the production of NADPH oxidase 4 (NOX4) and in turn the increase of intracellular reactive oxygen species (ROS), consequently activating membrane expression of the ATP-binding cassette subfamily C member 1 (ABCC1) for drug efflux. Non-steroidal anti-inflammatory drug (NSAID) ibuprofen suppressed EFHD2 expression by leading to the proteasomal and lysosomal degradation of EFHD2 through a cyclooxygenase (COX)-independent mechanism. Combining ibuprofen with cisplatin enhanced antitumor responsiveness in a murine xenograft model in comparison with the individual treatment. In conclusion, we demonstrate that EFHD2 promotes chemoresistance through the NOX4-ROS-ABCC1 axis and therefore developing EFHD2-targeting strategies may offer a new avenue to improve adjuvant chemotherapy of lung cancer.

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EFHD2 increases resistance of lung cancer to cisplatin.

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EFHD2 enhances the NOX4-ROS-ABCC1signalingfor cisplatin efflux.

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Ibuprofen suppresses EFHD2 through both proteasomal and lysosomal degradationmechanisms

Selective inhibition of interleukin-1 receptor-associated kinase 1 ameliorates lipopolysaccharide-induced sepsis in mice

Interleukin-1 receptor-associated kinases (IRAKs), particularly IRAK1 and IRAK4, are important in transducing signal from Toll-like receptor 4. We interrogated if a selective inhibition of IRAK1 could alleviate lipopolysaccharide (LPS)-induced sepsis. In this study, we tested the impact of a novel selective IRAK1 inhibitor Jh-X-119-01 on LPS-induced sepsis in mice. Survival at day 5 was 13.3% in control group where septic mice were treated by vehicle, while the values were 37.5% (p = 0.046, vs. control) and 56.3% (p = 0.003, vs. control) for 5 mg/kg and 10 mg/kg Jh-X-119-01-treated mice. Jh-X-119-01 alleviated lung injury and reduced production of TNFα and IFNγ in peritoneal macrophages. Jh-X-119-01 decreased phosphorylation of NF-κB and mRNA levels of IL-6 and TNFα in LPS-treated macrophages in vitro. Jh-X-119-01 selectively inhibited IRAK1 phosphorylation comparing with a non-selective IRAK1/4 inhibitor which simultaneously inhibited phosphorylation of IRAK1 and IRAK4. Both Jh-X-119-01 and IRAK1/4 inhibitor increased survival of septic mice, but Jh-X-119-01-treated mice had higher blood CD11b⁺ cell counts than IRAK1/4 inhibitor-treated ones [24 h: (1.18 ± 0.26) × 10⁶/ml vs. (0.79 ± 0.20) × 10⁶/ml, p = 0.001; 48 h: (1.00 ± 0.30) × 10⁶/ml vs. (0.67 ± 0.23) × 10⁶/ml, p = 0.042]. IRAK1/4 inhibitor induced more apoptosis of macrophages than Jh-X-119-01 did in vitro. IRAK1/4 inhibitor decreased protein levels of anti-apoptotic BCL-2 and MCL-1 in RAW 264.7 and THP-1 cells, an effect not seen in Jh-X-119-01-treated cells. In conclusion, Jh-X-119-01 selectively inhibited activation of IRAK1 and protected mice from LPS-induced sepsis. Jh-X-119-01 showed less toxicity on macrophages comparing with a non-selective IRAK1/4 inhibitor.

Label-Free Proteomic Analysis Reveals Parasite-Specific Protein Alterations in Macrophages Following Leishmania amazonensis, Leishmania major, or Leishmania infantum Infection

Leishmania is an obligate intracellular parasite known to modulate the host cell to survive and proliferate. However, the complexity of host-parasite interactions remains unclear. Also, the outcome of the disease has been recognized to be species-specific and dependent on the host's immune responses. Proteomics has emerged as a powerful tool to investigate the host-pathogen interface, allowing us to deepen our knowledge about infectious diseases. Quantification of the relative amount of proteins in a sample can be achieved using label-free proteomics, and for the first time, we have used it to quantify Leishmania-specific protein alterations in macrophages. Protein extracts were obtained and digested, and peptides were identified and quantified using nano-LC coupled with tandem mass spectrometry analyses. Protein expression was validated by Western blot analysis. Integrated Proteomics Pipeline was used for peptide/protein identification and for quantification and data processing. Ingenuity Pathway Analysis was used for network analysis. In this work, we investigated how this intracellular parasite modulates protein expression on a host macrophage by comparing three different Leishmania species- L. amazonensis, one of the causative agents of cutaneous disease in the Amazon region; L. major, another causative agent of cutaneous leishmaniasis in Africa, the Middle East, China, and India; L. infantum, the causative agent of visceral leishmaniasis affecting humans and dogs in Latin America-and lipopolysaccharide stimulated macrophages as an in vitro inflammation model. Our results revealed that Leishmania infection downregulates apoptosis pathways while upregulating the activation of phagocytes/leukocytes and lipid accumulation.

Quantification of Human Swiprosin-1/EFhd2 Expression on Protein and RNA Level

Many Ca²⁺-binding proteins are differentially regulated under pro-inflammatory conditions in different organs. Specific quantification of RNA and protein expression of those proteins demands validated protocols. Peripheral blood mononuclear cells (PBMC) can mirror an inflammatory status originating from several organs and can therefore be an important diagnostic tool. Swiprosin-1/EFhd2 (EFhd2) is a ~30 kDa Ca²⁺ and F-actin binding, cytoskeletal protein with two central EF hands and a C-terminal coiled-coil domain. Unbiased gene expression analyses and proteomics revealed that EFhd2 is regulated under pro-inflammatory conditions in several cell types and tissues. Here we describe validated protocols to quantify the expression of the human orthologue of Swiprosin-1/EFhd2 on RNA and protein level in PBMC. Both methods reveal that EFhd2 is stronger expressed in monocytes than in B cells of healthy donors. Thus, initial experiments relying on qPCR are likely to provide results with functional relevance. The higher expression of EFhd2 in monocytes could be related to monocyte migration under inflammatory conditions.

Conserved Noncoding Sequences Boost ADR1 and SP1 Regulated Human Swiprosin-1 Promoter Activity

Swiprosin-1 is expressed in various types of cells or tissues of different species. To investigate the mechanisms underlying Swiprosin-1 expression pattern, we analyzed the promoter activity of 2-kilobase genomic sequences located at 5′ flanking region of the Swiprosin-1 gene. The −2000/+41 bp of 5′ flanking untranslated promoter region of Swiprosin-1 gene was constitutively transactivated without significant effect of PMA, A23187, or PMA/A23187 stimulation in Jurkat T cells. Further, we identified 5′ deletant of proximal promoter region (−100/+41 to −70/+41) plays a pivotal role in activating the Swiprosin-1 gene in Jurkat T cells. Our studies also verified that ADR1 and Sp1 transcription factors were located between −70 and -100 locus of 5′ flanking proximal promoter region, which is critical for the Swiprosin-1 promoter activity. ADR1 and Sp1 were shown to bind the regions of −82, −79, −76, −73 and −70 and; −79, −78 and −77, respectively, within the proximal promoter region of Swiprosin-1. Finally conserved noncoding sequences (CNS) -1, -2 and -3 were located between the exon 1 and exon 2 of Swiprosin-1 gene and synergistically transactivated the Swiprosin-1 promoter. In summary, Swiprosin-1 was constitutively expressed in Jurkat T cells by the coordinate action of ADR1 and SP1 transcription factors at the transcriptional level and CNS further boost the proximal region of Swiprosin-1 promoter activity. Our findings provide novel insights that the transcriptional regulation of Swiprosin-1 by targeting ADR1 and Sp1 binding sites may be helpful in exploring novel therapeutic strategies for advanced immune or other disorders.

EF Hand Domain Family Member D2 Is Required for T Cell Cytotoxicity

Programmed cell death 1 (PD-1) is a major coinhibitory receptor and a member of the immunological synapse (IS). To uncover proteins that regulate PD-1 recruitment to the IS, we searched for cytoskeleton-related proteins that also interact with PD-1 using affinity purification mass spectrometry. Among these proteins, EF hand domain family member D2 (EFHD2), a calcium binding adaptor protein, was functionally and mechanistically analyzed for its contribution to PD-1 signaling. EFHD2 was required for PD-1 to inhibit cytokine secretion, proliferation, and adhesion of human T cells. Interestingly, EFHD2 was also required for human T cell-mediated cytotoxicity and for mounting an antitumor immune response in a syngeneic murine tumor model. Mechanistically, EFHD2 contributed to IS stability, lytic vesicles trafficking, and granzyme B secretion. Altogether, EFHD2 is an important regulator of T cell cytotoxicity and further studies should evaluate its role in T cell-mediated inflammation.