A new therapeutic target for systemic lupus erythematosus: The current landscape for drug development of a toll-like receptor 7/8 antagonist through academia-industry …

Nature Communications

Periodontitis, which is induced by repeated bacterial invasion and the ensuing immune reactions that follow, is the leading cause of tooth loss. Periodontal tissue is comprised of four different components, each with potential role in pathogenesis, however, most studies on immune responses focus on gingival tissue. Here, we present a modified ligature-induced periodontitis model in male mice to analyze the pathogenesis, which captures the complexity of periodontal tissue. We find that the inflammatory response in the peri-root tissues and the expression of IL-6 and RANKL by Thy-1.2− fibroblasts/stromal cells are prominent throughout the bone destruction phase, and present already at an early stage. The initiation phase is characterized by high levels of ST2 (encoded by Il1rl1) expression in the peri-root tissue, suggesting that the IL-33/ST2 axis is involved in the pathogenesis. Both Il1rl1- and Il33-deficient mice …

Rheumatology

Objectives Platelets and low-density neutrophils (LDNs) are major players in the immunopathogenesis of SLE. Despite evidence showing the importance of platelet–neutrophil complexes (PNCs) in inflammation, little is known about the relationship between LDNs and platelets in SLE. We sought to characterize the role of LDNs and Toll-like receptor 7 (TLR7) in clinical disease. Methods Flow cytometry was used to immunophenotype LDNs from SLE patients and controls. The association of LDNs with organ damage was investigated in a cohort of 290 SLE patients. TLR7 mRNA expression was assessed in LDNs and high-density neutrophils (HDNs) using publicly available mRNA sequencing datasets and our own cohort using RT-PCR. The role of TLR7 in platelet binding was evaluated in platelet–HDN mixing studies using TLR7-deficient mice and Klinefelter syndrome …

Nutrients

The cellular and molecular mechanisms of atherosclerosis are still unclear. Type 2 innate lymphocytes (ILC2) exhibit anti-inflammatory properties and protect against atherosclerosis. This study aimed to elucidate the pathogenesis of atherosclerosis development using atherosclerosis model mice (ApoE KO mice) and mice deficient in IL-33 receptor ST2 (ApoEST2 DKO mice). Sixteen-week-old male ApoE KO and ApoEST2 DKO mice were subjected to an 8-week regimen of a high-fat, high-sucrose diet. Atherosclerotic foci were assessed histologically at the aortic valve ring. Chronic inflammation was assessed using flow cytometry and real-time polymerase chain reaction. In addition, saturated fatty acids (palmitic acid) and IL-33 were administered to human aortic endothelial cells (HAECs) to assess fatty acid metabolism. ApoEST2 DKO mice with attenuated ILC2 had significantly worse atherosclerosis than ApoE KO mice. The levels of saturated fatty acids, including palmitic acid, were significantly elevated in the arteries and serum of ApoEST2 DKO mice. Furthermore, on treating HAECs with saturated fatty acids with or without IL-33, the Oil Red O staining area significantly decreased in the IL-33-treated group compared to that in the non-treated group. IL-33 potentially prevented the accumulation of saturated fatty acids within atherosclerotic foci.

medRxiv

Objectives To evaluate the safety, tolerability, pharmacokinetics (PK), biomarker response, and efficacy of E6742 in a phase 1/2 study in patients with systemic lupus erythematosus (SLE). Methods Two sequential cohorts of SLE patients were enrolled and randomized to 12 weeks of twice-daily treatment with E6742 (100 or 200 mg; n = 8 or 9) or placebo (n = 9). Results The proportion of patients with any treatment-emergent adverse events (TEAEs) was 58.8% in the E6742 group (37.5% for 100 mg; 77.8% for 200 mg) and 66.7% in the placebo group. No Common Terminology Criteria for Adverse Events ≥ Grade 3 TEAEs occurred. PK parameter levels were similar between SLE patients and healthy adults in previous phase 1 studies. The interferon gene signature (IGS) and levels of proinflammatory cytokines (interleukin-1β, interleukin-6, tumor necrosis factor-α) after ex-vivo challenge with a Toll-like receptor 7/8 agonist were immediately decreased by E6742 treatment. Dose-dependent improvements in the British Isles Lupus Assessment Group-based Composite Lupus Assessment response were observed at Week 12 in the E6742 (37.5% for 100 mg; 57.1% for 200 mg) and placebo (33.3%) groups. E6742 also had therapeutic effects on other symptoms, including skin inflammation, arthritis, and levels of anti-double-stranded DNA antibodies and complements. Conclusions E6742 had a favorable safety profile and was well tolerated, with marked IGS responses and sufficient efficacy signals in patients with SLE. These results provide the first clinical evidence to support E6742 in the treatment of SLE, and support larger, longer-term clinical trials.

International Immunology

Transforming growth factor-β-activated kinase 1 (TAK1) plays a pivotal role in innate and adaptive immunity. TAK1 is essential for the activation of mitogen-activated protein kinases (MAPKs) and nuclear factor (NF)-κB pathways downstream of diverse immune receptors, including Toll-like receptors (TLRs). Upon stimulation with TLR ligands, TAK1 is activated via recruitment to lysine 63-linked polyubiquitin chain through TAK1-binding proteins (TAB) 2 and TAB3. However, the physiological importance of TAB2 and TAB3 in macrophages is still controversial. A previous study has shown that mouse bone marrow-derived macrophages (BMDMs) isolated from mice double deficient for TAB2 and TAB3 produced tumor necrosis factor (TNF)-α and interleukin (IL)-6 to the similar levels as control wild-type BMDMs in response to TLR ligands such as lipopolysaccharide (LPS) or Pam3CSK4, indicating that TAB2 and …

Nature

The immune system has a critical role in orchestrating tissue healing. As a result, regenerative strategies that control immune components have proved effective 1, 2. This is particularly relevant when immune dysregulation that results from conditions such as diabetes or advanced age impairs tissue healing following injury 2, 3. Nociceptive sensory neurons have a crucial role as immunoregulators and exert both protective and harmful effects depending on the context 4, 5, 6, 7, 8, 9, 10, 11, 12. However, how neuro–immune interactions affect tissue repair and regeneration following acute injury is unclear. Here we show that ablation of the Na V 1.8 nociceptor impairs skin wound repair and muscle regeneration after acute tissue injury. Nociceptor endings grow into injured skin and muscle tissues and signal to immune cells through the neuropeptide calcitonin gene-related peptide (CGRP) during the healing process …

Journal of Experimental & Clinical Cancer Research

BackgroundPancreatitis is known to be an important risk factor for pancreatic ductal adenocarcinoma (PDAC). However, the exact molecular mechanisms of how inflammation promotes PDAC are still not fully understood. Regnase-1, an endoribonuclease, regulates immune responses by degrading mRNAs of inflammation-related genes. Herein, we investigated the role of Regnase-1 in PDAC.MethodsClinical significance of intratumor Regnase-1 expression was evaluated by immunohistochemistry in 39 surgically-resected PDAC patients. The functional role of Regnase-1 was investigated by pancreas-specific Regnase-1 knockout mice and Kras-mutant Regnase-1 knockout mice. The mechanistic studies with gene silencing, RNA immunoprecipitation sequencing (RIP-seq) and immune cell reconstitution were performed in human/mouse PDAC cell lines and a syngeneic orthotopic tumor transplantation model of …

Cardiovascular Research

Aims Microsomal prostaglandin E synthase-1 (mPGES-1)/prostaglandin E2 (PGE2) induces angiogenesis through the prostaglandin E2 receptor (EP1–4). Among immune cells, regulatory T cells (Tregs), which inhibit immune responses, have been implicated in angiogenesis, and PGE2 is known to modulate the function and differentiation of Tregs. We hypothesized that mPGES-1/PGE2-EP signalling could contribute to recovery from ischaemic conditions by promoting the accumulation of Tregs. Methods and results Wild-type (WT), mPGES-1-deficient (mPges-1−/−), and EP4 receptor-deficient (Ep4−/−) male mice, 6–8 weeks old, were used. Hindlimb ischaemia was induced by femoral artery ligation. Recovery from ischaemia was suppressed in mPges-1−/− mice and compared with WT mice. The number of accumulated forkhead box protein P3 (FoxP3)+ cells in ischaemic …

Immunity

Lung infection during severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) via the angiotensin-I-converting enzyme 2 (ACE2) receptor induces a cytokine storm. However, the precise mechanisms involved in severe COVID-19 pneumonia are unknown. Here, we showed that interleukin-10 (IL-10) induced the expression of ACE2 in normal alveolar macrophages, causing them to become vectors for SARS-CoV-2. The inhibition of this system in hamster models attenuated SARS-CoV-2 pathogenicity. Genome-wide association and quantitative trait locus analyses identified a IFNAR2-IL10RB readthrough transcript, COVID-19 infectivity-enhancing dual receptor (CiDRE), which was highly expressed in patients harboring COVID-19 risk variants at the IFNAR2 locus. We showed that CiDRE exerted synergistic effects via the IL-10-ACE2 axis in alveolar macrophages and functioned as a decoy receptor for type I …

Journal of Clinical Microbiology

Because nontuberculous mycobacterial pulmonary disease is a considerable health burden, a simple and clinically applicable analytical protocol enabling the identification of subspecies and drug-resistant disease is required to determine the treatment strategy. We aimed to develop a simplified workflow consisting only of direct sequencing of mycobacterial growth indicator tube cultures (MGIT-seq). In total, 138 patients were prospectively enrolled between April 2021 and May 2022, and culture-positive MGIT broths were subjected to sequencing using MinION, a portable next-generation sequencer. Sequence analysis was conducted to identify species using core genome multilocus sequence typing and to predict macrolide and amikacin (AMK) resistance based on previously reported mutations in rrl, rrs, and erm(41). The results were compared to clinical tests for species identification and drug susceptibility. A …

Journal of Experimental Medicine

Loss-of-function mutations in the lysosomal nucleoside transporter SLC29A3 cause lysosomal nucleoside storage and histiocytosis: phagocyte accumulation in multiple organs. However, little is known about the mechanism by which lysosomal nucleoside storage drives histiocytosis. Herein, histiocytosis in Slc29a3−/− mice was shown to depend on Toll-like receptor 7 (TLR7), which senses a combination of nucleosides and oligoribonucleotides (ORNs). TLR7 increased phagocyte numbers by driving the proliferation of Ly6Chi immature monocytes and their maturation into Ly6Clow phagocytes in Slc29a3−/− mice. Downstream of TLR7, FcRγ and DAP10 were required for monocyte proliferation. Histiocytosis is accompanied by inflammation in SLC29A3 disorders. However, TLR7 in nucleoside-laden splenic monocytes failed to activate inflammatory responses. Enhanced production of proinflammatory cytokines was …

International Immunopharmacology

Alcaligenes faecalis was previously identified as an intestinal lymphoid tissue-resident commensal bacteria, and our subsequent studies showed that lipopolysaccharide and its core active element (i.e., lipid A) have a potent adjuvant activity to promote preferentially antigen-specific Th17 response and antibody production. Here, we compared A. faecalis lipid A (ALA) with monophosphoryl lipid A, a licensed lipid A–based adjuvant, to elucidate the immunological mechanism underlying the adjuvant properties of ALA. Compared with monophosphoryl lipid A, ALA induced higher levels of MHC class II molecules and costimulatory CD40, CD80, and CD86 on dendritic cells (DCs), which in turn resulted in strong T cell activation. Moreover, ALA more effectively promoted the production of IL-6 and IL-23 from DCs than did monophosphoryl lipid A, thus leading to preferential induction of Th17 and Th1 cells. As underlying …

The EMBO Journal

Tight regulation of Toll‐like receptor (TLR)‐mediated inflammatory responses is important for innate immunity. Here, we show that T‐cell death‐associated gene 51 (TDAG51/PHLDA1) is a novel regulator of the transcription factor FoxO1, regulating inflammatory mediator production in the lipopolysaccharide (LPS)‐induced inflammatory response. TDAG51 induction by LPS stimulation was mediated by the TLR2/4 signaling pathway in bone marrow‐derived macrophages (BMMs). LPS‐induced inflammatory mediator production was significantly decreased in TDAG51‐deficient BMMs. In TDAG51‐deficient mice, LPS‐ or pathogenic Escherichia coli infection‐induced lethal shock was reduced by decreasing serum proinflammatory cytokine levels. The recruitment of 14‐3‐3ζ to FoxO1 was competitively inhibited by the TDAG51‐FoxO1 interaction, leading to blockade of FoxO1 cytoplasmic translocation and thereby …

Periodontitis, which is induced by repeated bacterial invasion and the ensuing immune reactions that follow, is the leading cause of tooth loss. However, studies on immune responses are usually based on gingival tissue, although periodontal tissue is actually comprised of four different components. Here, we have developed a novel model to analyze the pathogenesis of periodontitis with different periodontal tissue components. We have found that the inflammatory response in the peri-root tissues and the expression of interleukin (IL)-6 and nuclear factor κ-Β ligand (RANKL) by Thy-1.2–fibroblasts/stromal cells were prominent during the course of bone destruction. Furthermore, a comprehensive analysis of the initiation phase confirmed these findings while revealing a high level of expression of ST2 (also known as IL33R and encoded by Il1rl1) in the peri-root tissue. Il1rl1 and Il33 deficient mice exhibited exacerbated bone loss in the acute phase of periodontitis, demonstrating the protective role of the IL-33/ST2 axis in acute inflammation. Thus, the findings obtained with this novel model show the crucial role of the peri-root tissue and advance our understanding of the etiology of periodontitis.

Genes to Cells

The RNA‐binding protein (RBP) Regnase‐1 is an endonuclease that regulates immune responses by modulating target mRNA stability. Regnase‐1 degrades a group of inflammation‐associated mRNAs, which contributes to a balanced immune response and helps prevent autoimmune diseases. Regnase‐1 also cleaves its own mRNA by binding stem‐loop (SL) RNA structures in its 3′UTR. To understand how this autoregulation is important for immune responses, we generated mice with a 2‐bp genome deletion in the target SL of the Regnase‐1 3′‐untranslated region (3′UTR). Deletion of these nucleotides inhibited SL formation and limited Regnase‐1‐mediated mRNA degradation. Mutant mice had normal hematopoietic cell differentiation. Biochemically, mutation of the 3′UTR SL increased Regnase‐1 mRNA stability and enhanced both Regnase‐1 mRNA and protein levels in mouse embryonic …

The EMBO Journal

Mitochondrial DNA (mtDNA) leakage into the cytoplasm can occur when cells are exposed to noxious stimuli. Specific sensors recognize cytoplasmic mtDNA to promote cytokine production. Cytoplasmic mtDNA can also be secreted extracellularly, leading to sterile inflammation. However, the mode of secretion of mtDNA out of cells upon noxious stimuli and its relevance to human disease remain unclear. Here, we show that pyroptotic cells secrete mtDNA encapsulated within exosomes. Activation of caspase‐1 leads to mtDNA leakage from the mitochondria into the cytoplasm via gasdermin‐D. Caspase‐1 also induces intraluminal membrane vesicle formation, allowing for cellular mtDNA to be taken up and secreted as exosomes. Encapsulation of mtDNA within exosomes promotes a strong inflammatory response that is ameliorated upon exosome biosynthesis inhibition in vivo. We further show that monocytes …

Hepatology

Conclusions:Our study identified that IL‐33 is pro‐regenerative in a noninjurious model of liver resection. The underlying mechanism involved IL‐33/ST2‐induced increase of serotonin release from enterochromaffin cells to portal blood and subsequent HTR2A/p70S6K activation in hepatocytes by serotonin. The findings implicate the potential of targeting the IL‐33/ST2/serotonin pathway to reduce the risk of post‐hepatectomy liver failure and small‐for‐size syndrome.

Journal of Investigative Dermatology

The relationship between chronic inflammation and carcinogenesis has been controversial, despite known clinical evidence such as development of squamous cell carcinoma (SCC) from chronic skin ulcer. We previously demonstrated that a ribonuclease Regnase-1 (Reg1) in keratinocytes, played a down-modulator of skin inflammation in a cross-regulatory fashion with proinflammatory signals. Here, we addressed whether Reg1 had a protective role in skin carcinogenesis. The two-stage carcinogenesis protocol allowed keratinocyte-specific Reg1 KO mice (K5. Cre+ Reg1 fl/fl: Reg1-cKO) mice developed 10 or more papillomas and several SCCs per head, while almost no tumor emerged in controls (Reg1 fl/fl). By repeated exposure to ultraviolet B irradiation, Reg1-cKO mice showed marked acanthosis and atypical epidermis resembling solar keratosis at much earlier timing compared with controls. These data …

Infection of the lungs with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) via the angiotensin I converting enzyme 2 (ACE2) receptor induces a type of systemic inflammation known as a cytokine storm. However, the precise mechanisms involved in severe coronavirus disease 2019 (COVID-19) pneumonia are unknown. Here, we show that interleukin-10 (IL-10) changed normal alveolar macrophages into ACE2-expressing M2c-type macrophages that functioned as spreading vectors for SARS-CoV-2 infection. The depletion of alveolar macrophages and blockade of IL-10 attenuated SARS-CoV-2 pathogenicity. Furthermore, genome-wide association and quantitative trait locus analyses identified novel mRNA transcripts in human patients, COVID-19 infectivity enhancing dual receptor (CiDRE), which has unique synergistic effects within the IL-10-ACE2 system in M2c-type macrophages. Our results demonstrate that alveolar macrophages stimulated by IL-10 are key players in severe COVID-19. Collectively, CiDRE expression levels are potential risk factors that predict COVID-19 severity, and CiDRE inhibitors might be useful as COVID-19 therapies.