Orosomucoid 1 is involved in the development of chronic allograft rejection after kidney transplantation

GGT1 is a SNP eQTL gene involved in STAT3 activation and associated with the development of Post-ERCP pancreatitis

Post-ERCP pancreatitis (PEP) is an acute pancreatitis caused by endoscopic-retrograde-cholangiopancreatography (ERCP). About 10% of patients develop PEP after ERCP. Here we show that gamma-glutamyltransferase 1 (GGT1)-SNP rs5751901 is an eQTL in pancreatic cells associated with PEP and a positive regulator of the IL-6 amplifier. More PEP patients had the GGT1 SNP rs5751901 risk allele (C) than that of non-PEP patients at Hokkaido University Hospital. Additionally, GGT1 expression and IL-6 amplifier activation were increased in PEP pancreas samples with the risk allele. A mechanistic analysis showed that IL-6-mediated STAT3 nuclear translocation and STAT3 phosphorylation were suppressed in GGT1-deficient cells. Furthermore, GGT1 directly associated with gp130, the signal-transducer of IL-6. Importantly, GGT1-deficiency suppressed inflammation development in a STAT3/NF-κB-dependent disease model. Thus, the risk allele of GGT1-SNP rs5751901 is involved in the pathogenesis of PEP via IL-6 amplifier activation. Therefore, the GGT1-STAT3 axis in pancreas may be a prognosis marker and therapeutic target for PEP.

External Validation of a Urinary Biomarker Risk Score for the Prediction of Steroid Responsiveness in Adults With Nephrotic Syndrome

Introduction

In idiopathic nephrotic syndrome, response to corticosteroids remains the best indicator of prognosis. Noninvasive markers to predict a patient's response to steroids would allow improved prognostication and a more personalized approach to management. We have previously derived a urinary biomarker risk score which can differentiate steroid sensitive nephrotic syndrome (SSNS) from steroid resistant nephrotic syndrome (SRNS) in children. The goal of this study was to validate this previously derived biomarker risk score in a cohort of steroid-naïve adult patients, to determine whether the panel could be used to predict steroid responsiveness at the time of initial diagnosis.

Methods

In this external validation study, clinical data, and urinary specimens (obtained before initiation of steroid treatment) from adult patients were used in the Nephrotic Syndrome Study Network (NEPTUNE) cohort. A panel of 5 previously identified and validated urinary biomarkers, including neutrophil gelatinase-associated lipocalin (NGAL), vitamin D binding protein (VDBP), Fetuin-A (FetA), Transthyretin (TTR), and alpha-1 acid glycoprotein 2 (AGP2) was measured. A summary risk score for steroid resistance was calculated based on biomarker concentrations. Receiver operating characteristic curves were created for each log-transformed biomarker concentration and for the individual and combined biomarker risk score.

Results

The urine biomarker risk score predicted development of steroid resistance, with optimal sensitivity and specificity of 0.74, and area under the receiver operating characteristic curve (AUC) of 0.79 using both absolute and creatinine-corrected concentrations.

Conclusion

This study validates the previously derived urinary biomarker risk score to predict steroid resistance in adult patients with nephrotic syndrome at initial diagnosis.

Identification of Potential Drug Targets for Antiplatelet Therapy Specifically Targeting Platelets of Old Individuals through Proteomic Analysis

Aging is a growing problem worldwide, and the prevalence and mortality of arterial and venous thromboembolism (VTE) are higher in the elderly than in the young population. To address this issue, various anticoagulants have been used. However, no evidence can confirm that antithrombotic agents are suitable for the elderly. Therefore, this study aims to investigate the platelet proteome of aged mice and identify antithrombotic drug targets specific to the elderly. Based on the proteome analysis of platelets from aged mice, 308 increased or decreased proteins were identified. Among these proteins, three targets were selected as potential antithrombotic drug targets. These targets are membrane proteins or related to platelet function and include beta-2-glycoprotein 1 (β2GP1, ApolipoproteinH (ApoH)), alpha-1-acid glycoprotein2 (AGP2, Orosomucoid-2 (Orm2)), and Ras-related protein (Rab11a).

Computer model of IL-6-dependent rheumatoid arthritis in F759 mice

The interleukin-6 (IL-6) amplifier, which describes the simultaneous activation of signal transducer and activator of transcription 3 (STAT3) and NF-κb nuclear factor kappa B (NF-κB), in synovial fibroblasts causes the infiltration of immune cells into the joints of F759 mice. The result is a disease that resembles human rheumatoid arthritis. However, the kinetics and regulatory mechanisms of how augmented transcriptional activation by STAT3 and NF-κB leads to F759 arthritis is unknown. We here show that the STAT3-NF-κB complex is present in the cytoplasm and nucleus and accumulates around NF-κB binding sites of the IL-6 promoter region and established a computer model that shows IL-6 and IL-17 (interleukin 17) signaling promotes the formation of the STAT3-NF-κB complex followed by its binding on promoter regions of NF-κB target genes to accelerate inflammatory responses, including the production of IL-6, epiregulin, and C-C motif chemokine ligand 2 (CCL2), phenotypes consistent with in vitro experiments. The binding also promoted cell growth in the synovium and the recruitment of T helper 17 (Th17) cells and macrophages in the joints. Anti-IL-6 blocking antibody treatment inhibited inflammatory responses even at the late phase, but anti-IL-17 and anti-TNFα antibodies did not. However, anti-IL-17 antibody at the early phase showed inhibitory effects, suggesting that the IL-6 amplifier is dependent on IL-6 and IL-17 stimulation at the early phase, but only on IL-6 at the late phase. These findings demonstrate the molecular mechanism of F759 arthritis can be recapitulated in silico and identify a possible therapeutic strategy for IL-6 amplifier-dependent chronic inflammatory diseases.

Mechanism and treatment for chronic antibody-mediated rejection in kidney transplant recipients

Chronic antibody-mediated rejection of kidney transplantation is a major cause of late-stage graft loss. Donor-specific antibodies are the main cause of antibody-mediated rejection; in particular, de novo donor-specific antibodies are a risk factor for chronic active antibody-mediated rejection. The level of de novo donor-specific antibodies tends to increase with time throughout long-term graft survival. Donor-specific antibodies induce humoral rejection through complement activation, which results in tissue injury and coagulation. Additionally, complement activation promotes the migration of inflammatory cells through the innate immune response, causing endothelial injury. This inflammatory response may cause persistent glomerulitis and peritubular capillaritis, leading to fixed pathological lesions that impair graft function. No treatment has been established for chronic antibody-mediated rejection, a condition in which antibody-mediated rejection becomes irreversible. Thus, antibody-mediated rejection must be detected and treated while it is still reversible. In this review, we discuss the development of de novo donor-specific antibodies and the mechanisms leading to chronic antibody-mediated rejection and summarize the current treatment options and the latest biomarkers for detecting chronic antibody-mediated rejection at an earlier stage.

An inflammatory bowel disease-associated SNP increases local thyroglobulin expression to develop inflammation in miniature dachshunds

Inflammatory colorectal polyp (ICRP) in miniature dachshunds (MDs) is a chronic inflammatory bowel disease (IBD) characterized by granulomatous inflammation that consists of neutrophil infiltration and goblet cell hyperplasia in the colon. Recently, we identified five MD-associated single-nucleotide polymorphisms (SNPs), namely PLG, TCOF1, TG, COL9A2, and COL4A4, by whole-exome sequencing. Here, we investigated whether TG c.4567C>T (p.R1523W) is associated with the ICRP pathology. We found that the frequency of the T/T SNP risk allele was significantly increased in MDs with ICRP. In vitro experiments showed that TG expression in non-immune cells was increased by inducing the IL-6 amplifier with IL-6 and TNF-α. On the other hand, a deficiency of TG suppressed the IL-6 amplifier. Moreover, recombinant TG treatment enhanced the activation of the IL-6 amplifier, suggesting that TG is both a positive regulator and a target of the IL-6 amplifier. We also found that TG expression together with two NF-κB targets, IL6 and CCL2, was increased in colon samples isolated from MDs with the T/T risk allele compared to those with the C/C non-risk allele, but serum TG was not increased. Cumulatively, these results suggest that the T/T SNP is an expression quantitative trait locus (eQTL) of TG mRNA in the colon, and local TG expression triggered by this SNP increases the risk of ICRP in MDs via the IL-6 amplifier. Therefore, TG c.4567C>T is a diagnostic target for ICRP in MDs, and TG-mediated IL-6 amplifier activation in the colon is a possible therapeutic target for ICRP.

Dupuytren's contracture-associated SNPs increase SFRP4 expression in non-immune cells including fibroblasts to enhance inflammation development

Dupuytren's contracture (DC) is an inflammatory fibrosis characterized by fibroproliferative disorders of the palmar aponeurosis, for which there is no effective treatment. Although several genome-wide association studies have identified risk alleles associated with DC, the functional linkage between these alleles and the pathogenesis remains elusive. We here focused on two single nucleotide polymorphisms (SNPs) associated with DC, rs16879765 and rs17171229, in secreted frizzled related protein 4 (SFRP4). We investigated the association of SRFP4 with the IL-6 amplifier, which amplifies the production of IL-6, growth factors and chemokines in non-immune cells and aggravates inflammatory diseases via NF-κB enhancement. Knockdown of SFRP4 suppressed activation of the IL-6 amplifier in vitro and in vivo, whereas the overexpression of SFRP4 induced the activation of NF-κB-mediated transcription activity. Mechanistically, SFRP4 induced NF-κB activation by directly binding to molecules of the ubiquitination SFC complex, such as IkBα and βTrCP, followed by IkBα degradation. Furthermore, SFRP4 expression was significantly increased in fibroblasts derived from DC patients bearing the risk alleles. Consistently, fibroblasts with the risk alleles enhanced activation of the IL-6 amplifier. These findings indicate that the IL-6 amplifier is involved in the pathogenesis of DC, particularly in patients harboring the SFRP4 risk alleles. Therefore, SFRP4 is a potential therapeutic target for various inflammatory diseases and disorders, including DC.

Identification of ORM1, vWF, SPARC, and PPBP as immune-related proteins involved in immune thrombocytopenia by quantitative LC-MS/MS

BACKGROUND

Immune thrombocytopenia (ITP) is a common autoimmune disease characterized by loss of immune tolerance to platelet autoantigens leading to excessive destruction and insufficient production of platelets.

METHOD

Quantitative liquid chromatography tandem mass spectrometry (LC-MS/MS) was performed to detect the differentially expressed proteins in bone marrow samples from active ITP patients and normal controls.

RESULT

Our bioinformatic analysis identified two upregulated proteins (ORM1 and vWF) and two downregulated proteins (PPBP and SPARC) related to immune function. The four proteins were all found to be related to the tumor necrosis factor (TNF) -α signalling pathway and involved in the pathogenesis of ITP in KEGG pathway analysis.

CONCLUSION

Bioinformatics analysis identified differentially expressed proteins in bone marrow that are involved in the TNF-α signalling pathway and are related to the activation of immune function in ITP patients. These findings could provide new ideas for research on the loss of immune tolerance in ITP patients.

Gateway reflexes are neural circuits that establish the gateway of immune cells to regulate tissue specific inflammation

INTRODUCTION

Tissue-specific inflammatory diseases are regulated by several mechanisms. The gateway reflex and IL-6 amplifier are two mechanisms involved in diseases that depend on the inflammatory cytokine IL-6. The gateway reflex activates specific neural pathways that cause autoreactive CD4+ T cells to pass through gateways in blood vessels toward specific tissues in tissue-specific inflammatory diseases. These gateways are mediated by the IL-6 amplifier, which describes enhanced NF-κB activation in nonimmune cells including endothelial cells at specific sites. In total, we have reported six gateway reflexes defined by their triggering stimulus: gravity, pain, electric stimulation, stress, light, and joint inflammation.

AREAS COVERED

This review summarizes the gateway reflex and IL-6 amplifier for the development of tissue-specific inflammatory diseases.

EXPERT OPINION

We expect that the IL-6 amplifier and gateway reflex will lead to novel therapeutic and diagnostic methods for inflammatory diseases, particularly tissue-specific ones.

ATP spreads inflammation to other limbs through crosstalk between sensory neurons and interneurons

Neural circuits between lesions are one mechanism through which local inflammation spreads to remote positions. Here, we show the inflammatory signal on one side of the joint is spread to the other side via sensory neuron-interneuron crosstalk, with ATP at the core. Surgical ablation or pharmacological inhibition of this neural pathway prevented inflammation development on the other side. Mechanistic analysis showed that ATP serves as both a neurotransmitter and an inflammation enhancer, thus acting as an intermediary between the local inflammation and neural pathway that induces inflammation on the other side. These results suggest blockade of this neural pathway, which is named the remote inflammation gateway reflex, may have therapeutic value for inflammatory diseases, particularly those, such as rheumatoid arthritis, in which inflammation spreads to remote positions.

Sjögren's syndrome-associated SNPs increase GTF2I expression in salivary gland cells to enhance inflammation development

Sjögren's syndrome (SS) is an autoimmune disease characterized by inflammation with lymphoid infiltration and destruction of the salivary glands. Although many genome-wide association studies have revealed disease-associated risk alleles, the functions of the majority of these alleles are unclear. Here, we show previously unrecognized roles of GTF2I molecules by using two SS-associated single nucleotide polymorphisms (SNPs), rs73366469 and rs117026326 (GTF2I SNPs). We found that the risk alleles of GTF2I SNPs increased GTF2I expression and enhanced nuclear factor-kappa B (NF-κB) activation in human salivary gland cells via the NF-κB p65 subunit. Indeed, the knockdown of GTF2I suppressed inflammatory responses in mouse endothelial cells and in vivo. Conversely, the over-expression of GTF2I enhanced NF-κB reporter activity depending on its p65-binding N-terminal leucine zipper domain. GTF2I is highly expressed in the human salivary gland cells of SS patients expressing the risk alleles. Consistently, the risk alleles of GTF2I SNPs were strongly associated with activation of the IL-6 amplifier, which is hyperactivation machinery of the NF-κB pathway, and lymphoid infiltration in the salivary glands of SS patients. These results demonstrated that GTF2I expression in salivary glands is increased in the presence of the risk alleles of GTF2I SNPs, resulting in activation of the NF-κB pathway in salivary gland cells. They also suggest that GTF2I could be a new therapeutic target for SS.

PSMP Is Discriminative for Chronic Active Antibody-Mediated Rejection and Associate With Intimal Arteritis in Kidney Transplantation

Chronic active antibody-mediated rejection (CAAMR) is an intermediate process that occurs during the development of chronic antibody-mediated rejection (CAMR), which is a key problem associated with the long-term kidney grafts survival. This study investigated the role played by PC3-secreted microprotein (PSMP) in the progression of CAAMR and CAMR. We showed that CAAMR and CAMR patients’ allografts dysfunction with declined survival rate, which suggested that earlier diagnosis and treatment of CAAMR might be important to prevent irreversible chronic injury of CAMR progression. We found PSMP was an important factor in the development of chronic antibody-mediated rejection. The PSMP expression increased significantly in CAAMR biopsy samples but not in CAMR and control patients, which distinguished CAAMR patients from CAMR and non-rejection patients. Moreover, our results showed that infiltration of CD68⁺ macrophages in CAAMR increased, and the correlation between CD68⁺ macrophages and PSMP expression in CAAMR patients was significant. Additionally, our data also revealed that intimal arteritis (v-lesion) accompanied by increased macrophage infiltration might have contributed to more graft loss in CAAMR, and PSMP expression was significantly associated with the v-lesion score. These results indicated that PSMP played an important role in the recruitment of macrophages and promote intimal arteritis inducing allograft lost in CAAMR progression. In future study PSMP could be a potential histopathological diagnostic biomarker and treatment target for CAAMR in kidney transplantation.

Orosomucoid 1 Attenuates Doxorubicin-Induced Oxidative Stress and Apoptosis in Cardiomyocytes via Nrf2 Signaling

Doxorubicin (DOX) is an effective anticancer drug, but its therapeutic use is limited by its cardiotoxicity. The principal mechanisms of DOX-induced cardiotoxicity are oxidative stress and apoptosis in cardiomyocytes. Orosomucoid 1 (ORM1), an acute-phase protein, plays important roles in inflammation and ischemic stroke; however, the roles and mechanisms of ORM1 in DOX-induced cardiotoxicity remain unknown. Therefore, in the present study, we aimed to investigate the function of ORM1 in cardiomyocytes experiencing DOX-induced oxidative stress and apoptosis. A DOX-induced cardiotoxicity animal model was established in C57BL/6 mice by administering an intraperitoneal injection of DOX (20 mg/kg), and the control group was intraperitoneally injected with the same volume of sterilized saline. The effects were assessed after 7 d. Additionally, H9c2 cells were stimulated with DOX (10 μM) for 24 h. The results showed decreased ORM1 and increased oxidative stress and apoptosis after DOX stimulation in vivo and in vitro. ORM1 overexpression significantly reduced DOX-induced oxidative stress and apoptosis in H9c2 cells. ORM1 significantly increased the expression of nuclear factor-like 2 (Nrf2) and its downstream protein heme oxygenase 1 (HO-1) and reduced the expression of the lipid peroxidation end product 4-hydroxynonenal (4-HNE) and the level of cleaved caspase-3. In addition, Nrf2 silencing reversed the effects of ORM1 on DOX-induced oxidative stress and apoptosis in cardiomyocytes. In conclusion, ORM1 inhibited DOX-induced oxidative stress and apoptosis in cardiomyocytes by regulating the Nrf2/HO-1 pathway, which might provide a new treatment strategy for DOX-induced cardiotoxicity.

Different glycoforms of alpha-1-acid glycoprotein contribute to its functional alterations in platelets and neutrophils

Alpha-1-acid glycoprotein (AGP-1) is a positive acute phase glycoprotein with uncertain functions. Serum AGP-1 (sAGP-1) is primarily derived from hepatocytes and circulates as 12-20 different glycoforms. We isolated a glycoform secreted from platelet-activating factor (PAF)-stimulated human neutrophils (nAGP-1). Its peptide sequence was identical to hepatocyte-derived sAGP-1, but nAGP-1 differed from sAGP-1 in its chromatographic behavior, electrophoretic mobility, and pattern of glycosylation. The function of these 2 glycoforms also differed. sAGP-1 activated neutrophil adhesion, migration, and neutrophil extracellular traps (NETosis) involving myeloperoxidase, peptidylarginine deiminase 4, and phosphorylation of ERK in a dose-dependent fashion, whereas nAGP-1 was ineffective as an agonist for these events. Furthermore, sAGP-1, but not nAGP-1, inhibited LPS-stimulated NETosis. Interestingly, nAGP-1 inhibited sAGP-1-stimulated neutrophil NETosis. The discordant effect of the differentially glycosylated AGP-1 glycoforms was also observed in platelets where neither of the AGP-1 glycoforms alone stimulated aggregation of washed human platelets, but sAGP-1, and not nAGP-1, inhibited aggregation induced by PAF or ADP, but not by thrombin. These functional effects of sAGP-1 correlated with intracellular cAMP accumulation and phosphorylation of the protein kinase A substrate vasodilator-stimulated phosphoprotein and reduction of Akt, ERK, and p38 phosphorylation. Thus, the sAGP-1 glycoform limits platelet reactivity, whereas nAGP-1 glycoform also limits proinflammatory actions of sAGP-1. These studies identify new functions for this acute phase glycoprotein and demonstrate that the glycosylation of AGP-1 controls its effects on 2 critical cells of acute inflammation.