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The Journal of Biological Chemistry Jun 2024Complement receptor 1 (CR1) is a membrane glycoprotein with a highly duplicated domain structure able to bind multiple ligands such as C3b and C4b, the activated...
Complement receptor 1 (CR1) is a membrane glycoprotein with a highly duplicated domain structure able to bind multiple ligands such as C3b and C4b, the activated fragments of complement components C3 and C4, respectively. We have previously used our knowledge of this domain structure to identify CSL040, a soluble extracellular fragment of CR1 containing the long homologous repeat (LHR) domains A, B, and C. CSL040 retains the ability to bind both C3b and C4b but is also a more potent complement inhibitor than other recombinant CR1-based therapeutics. To generate soluble CR1 variants with increased inhibitory potential across all three complement pathways, or variants with activity skewed to specific pathways, we exploited the domain structure of CR1 further by generating LHR domain duplications. We identified LHR-ABCC, a soluble CR1 variant containing a duplicated C3b binding C-terminal LHR-C domain that exhibited significantly enhanced alternative pathway inhibitory activity in vitro compared to CSL040. Another variant, LHR-BBCC, containing duplications of both LHR-B and LHR-C with four C3b binding sites, was shown to have reduced classical/lectin pathway inhibitory activity compared to CSL040, but comparable alternative pathway activity. Interestingly, multiplication of the C4b-binding LHR-A domain resulted in only minor increases in classical/lectin pathway inhibitory activity. The CR1 duplication variants characterized in these in vitro potency assays, as well as in affinity in solution C3b and C4b binding assays, not only provides an opportunity to identify new therapeutic molecules, but also additional mechanistic insights to the multiple interactions between CR1 and C3b/C4b.
PubMed: 38844131
DOI: 10.1016/j.jbc.2024.107451 -
BioRxiv : the Preprint Server For... May 2024Granzymes are a family of serine proteases mainly expressed by CD8 T cells, natural killer cells, and innate-like lymphocytes . Although their major role is thought to...
Granzymes are a family of serine proteases mainly expressed by CD8 T cells, natural killer cells, and innate-like lymphocytes . Although their major role is thought to be the induction of cell death in virally infected and tumor cells, accumulating evidence suggests some granzymes can regulate inflammation by acting on extracellular substrates . Recently, we found that the majority of tissue CD8 T cells in rheumatoid arthritis (RA) synovium, inflammatory bowel disease and other inflamed organs express granzyme K (GZMK) , a tryptase-like protease with poorly defined function. Here, we show that GZMK can activate the complement cascade by cleaving C2 and C4. The nascent C4b and C2a fragments form a C3 convertase that cleaves C3, allowing further assembly of a C5 convertase that cleaves C5. The resulting convertases trigger every major event in the complement cascade, generating the anaphylatoxins C3a and C5a, the opsonins C4b and C3b, and the membrane attack complex. In RA synovium, GZMK is enriched in areas with abundant complement activation, and fibroblasts are the major producers of complement C2, C3, and C4 that serve as targets for GZMK-mediated complement activation. Our findings describe a previously unidentified pathway of complement activation that is entirely driven by lymphocyte-derived GZMK and proceeds independently of the classical, lectin, or alternative pathways. Given the widespread abundance of -expressing T cells in tissues in chronic inflammatory diseases and infection, GZMK-mediated complement activation is likely to be an important contributor to tissue inflammation in multiple disease contexts.
PubMed: 38826230
DOI: 10.1101/2024.05.22.595315 -
Ecotoxicology and Environmental Safety Jul 2024Niclosamide (NIC) is a commonly used insecticide and molluscicide in the prevention and treatment of parasitic diseases in fish. The utilization of NIC has the potential...
Niclosamide (NIC) is a commonly used insecticide and molluscicide in the prevention and treatment of parasitic diseases in fish. The utilization of NIC has the potential to disrupt the microbial community present on the mucosal tissue of fish, leading to localized inflammatory responses. The objective of this study was to evaluate the impact of NIC on the immune system and bacterial populations within the gill and gut of Mylopharyngodon piceus. Fish were subjected to varying concentrations of NIC, including a control group (0 μg/L), a low NIC group (15% 96 h LC50, LNG, 9.8 μg/L), and a high NIC group (80% 96 h LC50, HNG, 52.5 μg/L). Gill and gut samples were collected 28 days post-exposure for analysis. The findings revealed that the 96-h LC for NIC was determined to be 65.7 μg/L, and histopathological examination demonstrated that exposure to NIC resulted in gill filament subepithelial edema, exfoliation, degeneration, and a decrease in gill filament length. Furthermore, the gut exhibited apical enterocyte degeneration and leucocyte infiltration following NIC exposure. Additionally, NIC exposure led to a significant elevation in the levels of immunoglobulin M (IgM), complement component 3 (C3), and complement component 4 (C4) in both gill and gut tissues. Moreover, the activity of lysozyme (LYZ) was enhanced in the gill, while the activities of peroxidase (POD) and immunoglobulin T (IgT) were increased in gut tissue. The exposure to NIC resulted in enhanced mRNA expression of c3, c9, tnfα, il6, il8, and il11 in the gill tissue, while decreasing c3 and il8 expression in the gut tissue. Furthermore, the natural resistance-associated macrophage protein (nramp) mRNA increased, and liver-expressed antimicrobial peptide 2 (leap2) mRNA decreased in gill and gut tissues. And hepcidin (hepc) mRNA levels rose in gill but fell in gut tissue. NIC exposure also led to a decrease in gill bacterial richness and diversity, which significantly differed from the control group, although this separation was not significant in the gut tissue. In conclusion, the administration of NIC resulted in alterations in both the immune response and mucosal microbiota of fish. Furthermore, it was noted that gills displayed a heightened vulnerability to sublethal effects of NIC in comparison to gut tissues.
Topics: Animals; Gills; Water Pollutants, Chemical; Larva; Carps; Gastrointestinal Microbiome; Insecticides; Microbiota
PubMed: 38805826
DOI: 10.1016/j.ecoenv.2024.116512 -
Life (Basel, Switzerland) May 2024The interaction between IgM and C1q represents the first step of the classical pathway of the complement system in higher vertebrates. To identify the significance of...
The interaction between IgM and C1q represents the first step of the classical pathway of the complement system in higher vertebrates. To identify the significance of particular IgM/C1q interactions, recombinant IgMs were used in both hexameric and pentameric configurations and with two different specificities, along with C1q derived from human serum (sC1q) and two recombinant single-chain variants of the trimeric globular region of C1q. Interaction and complement activation assays were performed using the ELISA format, and bio-layer interferometry measurements to study kinetic behavior. The differences between hexameric and pentameric IgM conformations were only slightly visible in the interaction assay, but significant in the complement activation assay. Hexameric IgM requires a lower concentration of sC1q to activate the complement compared to pentameric IgM, leading to an increased release of C4 compared to pentameric IgM. The recombinant C1q mimetics competed with sC1q in interaction assays and were able to inhibit complement activation. The bio-layer interferometry measurements revealed K values in the nanomolar range for the IgM/C1q interaction, while the C1q mimetics exhibited rapid on and off binding rates with the IgMs. Our results make C1q mimetics valuable tools for developing recombinant C1q, specifically its variants, for further scientific studies and clinical applications.
PubMed: 38792658
DOI: 10.3390/life14050638 -
Life (Basel, Switzerland) Apr 2024Niclosamide (NIC) is a potent salicylanilide molluscicide/helminthicide commonly utilized for parasite and mollusc control in aquatic environments. Due to its persistent...
Niclosamide (NIC) is a potent salicylanilide molluscicide/helminthicide commonly utilized for parasite and mollusc control in aquatic environments. Due to its persistent presence in water bodies, there is growing concern regarding its impact on aquatic organisms, yet this remains inadequately elucidated. Consequently, this study aims to assess the hepatotoxic effects and detoxification capacity of black carp () in a semi-static system, employing various parameters for analysis. NIC was applied to juvenile black carp at three different concentrations (0, 10 and 50 μg/L) for 28 days in an environmentally realistic manner. Exposure to 50 μg/L NIC resulted in an increase in hepatic lysozyme (LYZ), alkaline phosphatase (ALP), and complement 4 (C4) levels while simultaneously causing a decrease in peroxidase (POD) activity. Additionally, NIC exposure exhibited a dose-dependent effect on elevating serum levels of LYZ, ALP, complement 3 (C3), C4, and immunoglobulin T (IgT). Notably, the mRNA levels of immune-related genes , , and , as well as and , were upregulated in fish exposed to NIC. RNA-Seq analysis identified 219 differentially expressed genes (DEGs) in after NIC exposure, with 94 upregulated and 125 downregulated genes. KEGG and GO analyses showed enrichment in drug metabolism pathways and activities related to oxidoreductase, lip oprotein particles, and cholesterol transport at 50 μg/L NIC. Additionally, numerous genes associated with lipid metabolism, oxidative stress, and innate immunity were upregulated in NIC-exposed . Taken together, these findings indicate that NIC has the potential to cause hepatotoxicity and immunotoxicity in . This research offers important insights for further understanding the impact of molluscicide/helminthicide aquatic toxicity in ecosystems.
PubMed: 38792567
DOI: 10.3390/life14050544 -
Biomedicines Apr 2024Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder identified by hematological abnormalities including anemia, leukopenia, and thrombocytopenia....
Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder identified by hematological abnormalities including anemia, leukopenia, and thrombocytopenia. Complement system disturbance is implicated in the pathogenesis of SLE. In this work, we aim to study how a full assessment of the complement system, which includes the evaluation of its three pathways, relates to blood cell counts in a population of patients with SLE. New-generation functional assays of the classical, alternative, and lectin pathways of the complement system were conducted in 284 patients with SLE. Additionally, serum levels of inactive molecules (C1q, C2, C3, C4, factor D) and activated molecules (C3a), as well as regulators (C1-inhibitor and factor H), were evaluated. Complete blood cell counts were analyzed. Multivariable linear regression analysis was performed to study the relationship of hematological profiles with this full characterization of the complement system. After multivariable adjustments that included age, sex, SLICC-DI (damage), and SLEDAI (activity) scores, as well as the use of aspirin, prednisone, methotrexate, azathioprine, and mycophenolate mofetil, several relationships were observed between the C pathways and the individual products and blood cells profile. Lower values of C1q and C2 were associated with lower hemoglobin levels. Lower leukocyte counts showed significantly lower values of C4, C1 inhibitor, C3, factor D, and alternative pathway functional levels. Neutrophil counts showed significant negative relationships only with the alternative pathway and C1-inh. In the case of lymphocytes, associations were found, especially with functional tests of the classical and alternative pathways, as well as with C2, C4, C3, and C3a. On the contrary, for platelets, significance was only observed, after multivariable adjustment, with lower C2 concentrations. In conclusion, the serum complement system and hematological profile in SLE are independently linked, after adjustment for disease activity and damage. These relationships are basically negative and are predominantly found in lymphocytes.
PubMed: 38790929
DOI: 10.3390/biomedicines12050967 -
Diseases (Basel, Switzerland) Apr 2024Although lymphoma is the most frequent malignancy in common variable immunodeficiency (CVID), solid tumors, especially affected by oncogenic viruses, are not considered....
Role of B Cells beyond Antibodies in HBV-Induced Oncogenesis: Fulminant Cancer in Common Variable Immunodeficiency-Clinical and Immunotransplant Implications with a Review of the Literature.
Although lymphoma is the most frequent malignancy in common variable immunodeficiency (CVID), solid tumors, especially affected by oncogenic viruses, are not considered. Furthermore, in vitro genetic studies and cell cultures are not adequate for immune system and HBV interaction. We adopted a previously introduced clinical model of host-virus interaction (i.e., infectious process in immunodeficiency) for analysis of B cells and the specific IgG role (an observational study of a CVID patient who received intravenous immunoglobulin (IVIG). Suddenly, the patient deteriorated and a positive results of for HBs and HBV-DNA (369 × 10 copies) were detected. Despite lamivudine therapy and IVIG escalation (from 0.3 to 0.4 g/kg), CT showed an 11 cm intrahepatic tumor (hepatocellular carcinoma). Anti-HBs were positive in time-lapse analysis (range 111-220 IU/mL). Replacement therapy intensification was complicated by an immune complex disease with renal failure. Fulminant HCC in CVID and the development of a tumor as the first sign is of interest. Unfortunately, treatment with hepatitis B immune globulins (HBIG) plays a major role in posttransplant maintenance therapy. Anti-HB substitution has not been proven to be effective, oncoprotective, nor safe. Therefore, immunosuppression in HBV-infected recipients should be carefully minimized, and patient selection more precise with the exclusion of HBV-positive donors. Our clinical model showed an HCC pathway with important humoral host factors, contrary to epidemiological/cohort studies highlighting risk factors only (e.g., chronic hepatitis). The lack of cell cooperation as well as B cell deficiency observed in CVID play a crucial role in high HBV replication, especially in carcinogenesis.
PubMed: 38785735
DOI: 10.3390/diseases12050080 -
Current Issues in Molecular Biology May 2024Hematopoietic stem cell transplantation (HSCT) remains a cornerstone in the management of patients with hematological malignancies. Endothelial injury syndromes, such as... (Review)
Review
Hematopoietic stem cell transplantation (HSCT) remains a cornerstone in the management of patients with hematological malignancies. Endothelial injury syndromes, such as HSCT-associated thrombotic microangiopathy (HSCT-TMA), veno-occlusive disease/sinusoidal obstruction syndrome (SOS/VOD), and capillary leak syndrome (CLS), constitute complications after HSCT. Moreover, endothelial damage is prevalent after immunotherapy with chimeric antigen receptor-T (CAR-T) and can be manifested with cytokine release syndrome (CRS) or immune effector cell-associated neurotoxicity syndrome (ICANS). Our literature review aims to investigate the genetic susceptibility in endothelial injury syndromes after HSCT and CAR-T cell therapy. Variations in complement pathway- and endothelial function-related genes have been associated with the development of HSCT-TMA. In these genes, , , , , , , , , , and are included. Thus, patients with these variations might have a predisposition to complement activation, which is also exaggerated by other factors (such as acute graft-versus-host disease, infections, and calcineurin inhibitors). Few studies have examined the genetic susceptibility to SOS/VOD syndrome, and the implicated genes include , and . Finally, specific mutations have been associated with the onset of CRS (, ) and ICANS (, , , ). More research is essential in this field to achieve better outcomes for our patients.
PubMed: 38785556
DOI: 10.3390/cimb46050288 -
Psychiatry and Clinical... Jun 2023There are increasing investigations about the potential role of the complement system in disorders affecting the central nervous system, including schizophrenia....
BACKGROUND
There are increasing investigations about the potential role of the complement system in disorders affecting the central nervous system, including schizophrenia. Therefore, we aim to evaluate the levels of complement 3 and complement 4 and the factors affecting treatment resistance in schizophrenia patients.
METHODS
This cross-sectional study was conducted between January 2020 and January 2021 and included schizophrenia patients resistant to treatment or in remission and healthy controls. The Structured Clinical Interview for Diagnostic and Statistical Manual-5 was used to confirm the diagnosis according to Diagnostic and Statistical Manual -5 criteria. We evaluated the patients with some scales and forms. The complement 3 and complement 4 levels were measured from blood samples.
RESULTS
In the treatment-resistant schizophrenia group, complement 3 ( = .001) and complement 4 (001) levels were significantly higher compared to schizophrenia patients in remission and healthy controls. While the Brief Psychiatric Rating Scale (001), the Positive and Negative Syndrome Scale-positive (001), the Positive and Negative Syndrome Scale-negative (001), the Positive and Negative Syndrome Scale-psychopathology (001), the Positive and Negative Syndrome Scale-total (001), and the Clinical Global Impression Scale-Severity (001) scores were significantly higher in treatment-resistant schizophrenia patients, the General Assessment of Functioning (001), and Beck Cognitive Insight Scale (001) scores were significantly lower compared to the other groups. In schizophrenia patients, complement 3 levels were positively correlated with the Positive and Negative Syndrome Scale-negative (046), the Positive and Negative Syndrome Scale-psychopathology (001), the Positive and Negative Syndrome Scale -total (025), and Clinical Global Impression Scale-Severity of Disease (004). Also, complement 4 levels were positively correlated with Brief Psychiatric Rating Scale (004), the Positive and Negative Syndrome Scale-positive (003), the Positive and Negative Syndrome Scale -negative (014), the Positive and Negative Syndrome Scale-psychopathology (001), the Positive and Negative Syndrome Scale-total (002), and Clinical Global Impression Scale-Severity of Disease (001) in patients with schizophrenia. It was determined that a higher C4 level increased the risk of treatment resistance (odds ratio: 1.133, 95% CI: 1.012-1.268; 030), while a higher Beck Cognitive Insight Scale score decreased the risk of treatment resistance (odds ratio: 0.317, 95% CI: 0.191-0.526; 001).
CONCLUSION
In light of the analyses, it can be said that complement concentration increases in certain stages of schizophrenia, and its imbalance may be associated with symptom severity and treatment resistance.
PubMed: 38765923
DOI: 10.5152/pcp.2023.22580 -
Frontiers in Immunology 2024Kidney transplant recipients often experience significant alterations in their immune system, which can lead to increased susceptibility to infections. This study aimed...
INTRODUCTION
Kidney transplant recipients often experience significant alterations in their immune system, which can lead to increased susceptibility to infections. This study aimed to analyze time-dependent changes in serum immunoglobulin and complement levels and determine the risk factors associated with infection.
METHODS
A retrospective analysis of serum samples from 192 kidney transplant recipients who received transplantations between August 2016 and December 2019 was conducted. The serum samples were obtained at preoperative baseline (T0), postoperative 2 weeks (T1), 3 months (T2), and 1 year (T3). The levels of serum C3, C4, IgG, IgA, and IgM were measured to evaluate immune status over time.
RESULTS
The analysis revealed significant decreases in IgG and IgA levels at T1. This period was associated with the highest occurrence of hypogammaglobulinemia (HGG) and hypocomplementemia (HCC), as well as an increased incidence of severe infection requiring hospitalization and graft-related viral infections. Using a time-dependent Cox proportional hazards model adjusted for time-varying confounders, HGG was significantly associated with an increased risk of infection requiring hospitalization (HR, 1.895; 95% CI: 1.871-1.920, P-value<0.001) and graft-related viral infection (HR, 1.152; 95% CI: 1.144-1.160, P-value<0.001).
DISCUSSION
The findings suggest that monitoring serum immunoglobulin levels post-transplant provides valuable insights into the degree of immunosuppression. Hypogammaglobulinemia during the early post-transplant period emerges as a critical risk factor for infection, indicating that serum immunoglobulins could serve as feasible biomarkers for assessing infection risk in kidney transplant recipients.
Topics: Humans; Kidney Transplantation; Male; Female; Middle Aged; Retrospective Studies; Adult; Time Factors; Immunoglobulins; Risk Factors; Agammaglobulinemia; Biomarkers; Infections
PubMed: 38707898
DOI: 10.3389/fimmu.2024.1374535