Antigen delivery by alpha(2)-macroglobulin enhances the cytotoxic T lymphocyte response

The trajectory of vesicular proteomic signatures from HBV-HCC by chitosan-magnetic bead-based separation and DIA-proteomic analysis

Hepatocellular carcinoma (HCC) is a prevalent primary liver cancer often associated with chronic hepatitis B virus infection (CHB) and liver cirrhosis (LC), underscoring the critical need for biomarker discovery to improve patient outcomes. Emerging as a promising avenue for biomarker development, proteomic technology leveraging liquid biopsy from small extracellular vesicles (sEV) offers new insights. Here, we evaluated various methods for sEV isolation and identified polysaccharide chitosan (CS) as an optimal approach. Subsequently, we employed optimized CS-based magnetic beads (Mag-CS) for sEV separation from serum samples of healthy controls, CHB, LC, and HBV-HCC patients. Leveraging data-independent acquisition mass spectrometry coupled with machine learning, we uncovered potential vesicular protein biomarker signatures (KNG1, F11, KLKB1, CAPNS1, CDH1, CPN2, NME2) capable of distinguishing HBV-HCC from CHB, LC, and non-HCC conditions. Collectively, our findings highlight the utility of Mag-CS-based sEV isolation for identifying early detection biomarkers in HBV-HCC.

Construction of monocyte-related prognosis model based on comprehensive analysis of bulk RNA-seq and single-cell RNA-seq in high-grade serous ovarian cancer

High-grade serous ovarian cancer (HGSOC) is a common subtype of ovarian cancer with high mortality. Finding a new biomarker is useful for the diagnosis and treatment of HGSOC. The scRNA and bulk RNA data were obtained from The Cancer Genome Atlas and Gene Expression Omnibus databases. The monocyte-related clusters were identified and annotated by Seruat and SingleR package. The Kaplan-Meier and receiver operating characteristic curve was used to determine the prognosis. The differentially expressed genes were determined by limma. The single sample Gene Set Enrichment Analysis, Gene Set Enrichment Analysis, Gene Ontology, and Kyoto Encyclopedia of Genes and Genomes were used for the enrichment function. The correlation between drug activity and gene expression was assessed by rcellminer and rcellminer Data package. We identified 9 cell types and obtained 37 differentially expressed marker genes of monocyte. A2M, CD163, and FPR1 were screened out as hub genes and used to construct risk model in HGSOC through univariate and multivariate cox analysis. Single sample Gene Set Enrichment Analysis showed risk score was related to B cell and T cell signal pathways, and further analysis showed most immune checkpoint genes expressions were upregulated in high-risk score group. The Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis exhibited that hub gene related genes were involved in signal receptor binding and cytokine-cytokine interaction. Low A2M expression and high expression of CD163 and FPR1 were associated with poor prognosis. Gene Set Enrichment Analysis revealed that A2M promoted tumor development through enhancing immune cell related signal pathways, while CD163 and FPR1 inhibited tumor development through activated carcinogenic signal pathways. Drug sensitivity analysis revealed that these hub genes could be potential therapeutic targets for the treatment of HGSOC. We constructed a risk model for the overall survival and explored the potential mechanism of monocyte in HGSOC.

Interaction of Iron Oxide Nanoparticles with Macrophages Is Influenced Distinctly by "Self" and "Non-Self" Biological Identities

Upon contact with biological fluids like serum, a protein corona (PC) complex forms on iron oxide nanoparticles (IONPs) in physiological environments and the proteins it contains influence how IONPs act in biological systems. Although the biological identity of PC-IONP complexes has often been studied in vitro and in vivo, there have been inconsistent results due to the differences in the animal of origin, the type of biological fluid, and the physicochemical properties of the IONPs. Here, we identified differences in the PC composition when it was derived from the sera of three species (bovine, murine, or human) and deposited on IONPs with similar core diameters but with different coatings [dimercaptosuccinic acid (DMSA), dextran (DEX), or 3-aminopropyl triethoxysilane (APS)], and we assessed how these differences influenced their effects on macrophages. We performed a comparative proteomic analysis to identify common proteins from the three sera that adsorb to each IONP coating and the 10 most strongly represented proteins in PCs. We demonstrated that the PC composition is dependent on the origin of the serum rather than the nature of the coating. The PC composition critically affects the interaction of IONPs with macrophages in self- or non-self identity models, influencing the activation and polarization of macrophages. However, such effects were more consistent for DMSA-IONPs. As such, a self biological identity of IONPs promotes the activation and M2 polarization of murine macrophages, while a non-self biological identity favors M1 polarization, producing larger quantities of ROS. In a human context, we observed the opposite effect, whereby a self biological identity of DMSA-IONPs promotes a mixed M1/M2 polarization with an increase in ROS production. Conversely, a non-self biological identity of IONPs provides nanoparticles with a stealthy character as no clear effects on human macrophages were evident. Thus, the biological identity of IONPs profoundly affects their interaction with macrophages, ultimately defining their biological impact on the immune system.

Multi-faceted role of LRP1 in the immune system

Graft versus host disease (GVHD) represents the major complication after allogeneic hematopoietic stem cell transplantation (Allo-SCT). GVHD-prone patients rely on GVHD prophylaxis (e.g. methotrexate) and generalized anti-GVHD medical regimen (glucocorticoids). New anti-GVHD therapy strategies are being constantly explored, however there is an urgent need to improve current treatment, since GVHD-related mortality reaches 22% within 5 years in patients with chronic GVHD. This review is an attempt to describe a very well-known receptor in lipoprotein studies - the low-density lipoprotein receptor related protein 1 (LRP1) - in a new light, as a potential therapeutic target for GVHD prevention and treatment. Our preliminary studies demonstrated that LRP1 deletion in donor murine T cells results in significantly lower GVHD-related mortality in recipient mice with MHC (major histocompatibility complex) -mismatched HSCT. Given the importance of T cells in the development of GVHD, there is a significant gap in scientific literature regarding LRP1's role in T cell biology. Furthermore, there is limited research interest and publications on this classical receptor molecule in other immune cell types. Herein, we endeavor to summarize existing knowledge about LRP1's role in various immune cells to demonstrate the possibility of this receptor to serve as a novel target for anti-GVHD treatment.

Alpha-2-Macroglobulin in Inflammation, Immunity and Infections

Alpha-2-macroglobulin is an extracellular macromolecule mainly known for its role as a broad-spectrum protease inhibitor. By presenting itself as an optimal substrate for endopeptidases of all catalytic types, alpha-2-macroglobulin lures active proteases into its molecular cage and subsequently ‘flags’ their complex for elimination. In addition to its role as a regulator of extracellular proteolysis, alpha-2-macroglobulin also has other functions such as switching proteolysis towards small substrates, facilitating cell migration and the binding of cytokines, growth factors and damaged extracellular proteins. These functions appear particularly important in the context of immune-cell function. In this review manuscript, we provide an overview of all functions of alpha-2-macroglobulin and place these in the context of inflammation, immunity and infections.

Identifying new molecular players in extracellular proteostasis

Proteostasis refers to a delicately tuned balance between the processes of protein synthesis, folding, localization, and the degradation of proteins found inside and outside cells. Our understanding of extracellular proteostasis is rather limited and largely restricted to knowledge of 11 currently established extracellular chaperones (ECs). This review will briefly outline what is known of the established ECs, before moving on to discuss experimental strategies used to identify new members of this growing family, and an examination of a group of putative new ECs identified using one of these approaches. An observation that emerges from an analysis of the expanding number of ECs is that all of these proteins are multifunctional. Strikingly, the armory of activities each possess uniquely suit them as a group to act together at sites of tissue damage, infection, and inflammation to restore homeostasis. Lastly, we highlight outstanding questions to guide future research in this field.

Metcalf Lecture Award: Applying niche biology to engineer T-cell regenerative therapies

The processes generating cells of adaptive immunity render them less amenable to the single cytokine signals used so effectively to regenerate myeloid cells. T-cell neogenesis begins in the bone marrow, where specific sets of late osteolineage cells govern the specification of hematopoietic cells capable of migrating to the thymus where differentiation is completed. Osteocalcin-expressing bone marrow stromal cells producing Dll4 serve as a progenitor niche enabling this T-competent cell production. Biocompatible alginate-based cryogels containing bone morphogenetic proteins (BMP-2) and the Notch ligand Dll4 were engineered to recapitulate the endogenous niche. These cryogels are highly pliable and can be injected under the skin of animals undergoing bone marrow transplantation. The result in mice is an ectopic niche fostering T-competent progenitor generation that results in improved T-cell numbers and receptor diversity. The recipients can generate neoantigen vaccine responses while having improved tolerance manifest by reduced graft-versus-host disease upon allogeneic transplant. Through emerging details of niches in the bone marrow, therapeutics more complex than those necessary for myeloid reconstitution are possible. Niche biology-guided bioengineered design offers the possibility of regenerative therapies for T lymphoid cells.

A proteomics analysis reveals that A2M might be regulated by STAT3 in persistent allergic rhinitis

BACKGROUND

Proteomics tools can be used to identify the differentially expressed proteins related to allergic rhinitis (AR). However, the large numbers of proteins related to AR have not yet been explored using an advanced quantitative proteomics approach, known as isobaric tags for relative and absolute quantitation (iTRAQ).

OBJECTIVES

To identify differentially expressed proteins in persistent AR patients and to explore the regulatory signalling pathways involving the identified proteins.

METHODS

Forty-five persistent AR patients and 20 healthy controls were recruited for this study. iTRAQ was used to identify the proteins that were differentially expressed between these two groups, and a bioinformatics analysis was then conducted to identify the signalling pathways associated with the identified proteins. Immunofluorescence labelling was performed to detect alpha-2-macroglobulin (A2M), STAT3, p-STAT3 and IL17 in the nasal mucosa.

RESULTS

A total of 133 differentially expressed proteins were identified. We then determined the top 10 regulatory pathways associated with these proteins and found that the blood coagulation pathway had the most significant association. A2M, a protein involved in the blood coagulation pathway, was found to be differentially expressed in the serum of AR patients. The bioinformatics analysis indicated that STAT3 is an upstream transcription factor that might regulate A2M expression. An immunofluorescence study further confirmed that STAT3 and A2M are co-localized in nasal mucosa cells. Additionally, A2M, STAT3, p-STAT3, and IL17 are elevated in AR patients. The expressional level of A2M is positively related to IL17 and the symptom of the congestion in AR subjects.

CONCLUSIONS

The blood coagulation pathway may be a key regulatory network pathway contributing to the allergic inflammatory response in AR patients. A2M, which is regulated by STAT3, may be an important protein in the pathogenesis of allergic rhinitis in AR patients.

Enhancement of antigen-specific CD4+ and CD8+ T cell responses using a self-assembled biologic nanolipoprotein particle vaccine

To address the need for vaccine platforms that induce robust cell-mediated immunity, we investigated the potential of utilizing self-assembling biologic nanolipoprotein particles (NLPs) as an antigen and adjuvant delivery system to induce antigen-specific murine T cell responses. We utilized OT-I and OT-II TCR-transgenic mice to investigate the effects of NLP-mediated delivery of the model antigen ovalbumin (OVA) on T cell activation. Delivery of OVA with the TLR4 agonist monophosphoryl lipid A (MPLA) in the context of NLPs significantly enhanced the activation of both CD4⁺ and CD8⁺ T cells in vitro compared to co-administration of free OVA and MPLA. Upon intranasal immunization of mice harboring TCR-transgenic cells, NLPs enhanced the adjuvant effects of MPLA and the in vivo delivery of OVA, leading to significantly increased expansion of CD4⁺ and CD8⁺ T cells in lung-draining lymph nodes. Therefore, NLPs are a promising vaccine platform for inducing T cell responses following intranasal administration.

LDL receptor-related protein-1 regulates NFκB and microRNA-155 in macrophages to control the inflammatory response

LDL receptor-related protein-1 (LRP1) is an endocytic and cell-signaling receptor. In mice in which LRP1 is deleted in myeloid cells, the response to lipopolysaccharide (LPS) was greatly exacerbated. LRP1 deletion in macrophages in vitro, under the control of tamoxifen-activated Cre-ER(T) fusion protein, robustly increased expression of proinflammatory cytokines and chemokines. In LRP1-expressing macrophages, proinflammatory mediator expression was regulated by LRP1 ligands in a ligand-specific manner. The LRP1 agonists, α2-macroglobulin and tissue-type plasminogen activator, attenuated expression of inflammatory mediators, even in the presence of LPS. The antagonists, receptor-associated protein (RAP) and lactoferrin (LF), and LRP1-specific antibody had the entirely opposite effect, promoting inflammatory mediator expression and mimicking LRP1 deletion. NFκB was rapidly activated in response to RAP and LF and responsible for the initial increase in expression of proinflammatory mediators. RAP and LF also significantly increased expression of microRNA-155 (miR-155) after a lag phase of about 4 h. miR-155 expression reflected, at least in part, activation of secondary cell-signaling pathways downstream of TNFα. Although miR-155 was not involved in the initial induction of cytokine expression in response to LRP1 antagonists, miR-155 was essential for sustaining the proinflammatory response. We conclude that LRP1, NFκB, and miR-155 function as members of a previously unidentified system that has the potential to inhibit or sustain inflammation, depending on the continuum of LRP1 ligands present in the macrophage microenvironment.

Specific deletion of LDL receptor-related protein on macrophages has skewed in vivo effects on cytokine production by invariant natural killer T cells

Expression of molecules involved in lipid homeostasis such as the low density lipoprotein receptor (LDLr) on antigen presenting cells (APCs) has been shown to enhance invariant natural killer T (iNKT) cell function. However, the contribution to iNKT cell activation by other lipoprotein receptors with shared structural and ligand binding properties to the LDLr has not been described. In this study, we investigated whether a structurally related receptor to the LDLr, known as LDL receptor-related protein (LRP), plays a role in iNKT cell activation. We found that, unlike the LDLr which is highly expressed on all immune cells, the LRP was preferentially expressed at high levels on F4/80+ macrophages (MΦ). We also show that CD169+ MΦs, known to present antigen to iNKT cells, exhibited increased expression of LRP compared to CD169- MΦs. To test the contribution of MΦ LRP to iNKT cell activation we used a mouse model of MΦ LRP conditional knockout (LRP-cKO). LRP-cKO MΦs pulsed with glycolipid alpha-galactosylceramide (αGC) elicited normal IL-2 secretion by iNKT hybridoma and in vivo challenge of LRP-cKO mice led to normal IFN-γ, but blunted IL-4 response in both serum and intracellular expression by iNKT cells. Flow cytometric analyses show similar levels of MHC class-I like molecule CD1d on LRP-cKO MΦs and normal glycolipid uptake. Survey of the iNKT cell compartment in LRP-cKO mice revealed intact numbers and percentages and no homeostatic disruption as evidenced by the absence of programmed death-1 and Ly-49 surface receptors. Mixed bone marrow chimeras showed that the inability iNKT cells to make IL-4 is cell extrinsic and can be rescued in the presence of wild type APCs. Collectively, these data demonstrate that, although MΦ LRP may not be necessary for IFN-γ responses, it can contribute to iNKT cell activation by enhancing early IL-4 secretion.

α-2-Macroglobulin: a physiological guardian

Alpha macroglobulins are large glycoproteins which are present in the body fluids of both invertebrates and vertebrates. Alpha-2-macroglobulin (α2 M), a key member of alpha macroglobulin superfamily, is a high-molecular weight homotetrameric glycoprotein. α2 M has many diversified and complex functions, but it is primarily known by its ability to inhibit a broad spectrum of proteases without the direct blockage of the protease active site. α2 M is also known to be involved in the regulation, transport, and a host of other functions. For example, apart from inhibiting proteinases, it regulates binding of transferrin to its surface receptor, binds defensin and myelin basic protein, etc., binds several important cytokines, including basic fibroblast growth factor (bFGF), platelet-derived growth factor (PDGF), nerve growth factor (NGF), interleukin-1β (IL-1β), and interleukin-6 (IL-6), and modify their biological activity. α2 M also binds a number of hormones and regulates their activity. α2 M is said to protect the body against various infections, and hence, can be used as a biomarker for the diagnosis and prognosis of a number of diseases. However, this multipurpose antiproteinse is not "fail safe" and could be damaged by reactive species generated endogenously or exogenously, leading to various pathophysiological conditions.

An anti-nucleic acid antibody delivers antigen to the cross-presentation pathway in dendritic cells and potentiates therapeutic antitumor effects

Cross-presentation is important for initiating CTL responses against tumors. Delivery of exogenous Ags to the cross-presentation pathway in dendritic cells (DCs), using a number of different carriers, has been attempted to further understand the mechanisms underlying cross-presentation and to develop therapeutic tumor vaccines. The present study reports a new antigenic carrier molecule: a single-chain V region fragment (scFv) of a nucleic acid-hydrolyzing Ab, 3D8. A fusion protein comprising 3D8 scFv and the CTL epitope OVA(250-264) (chicken OVA aa 250-264) was internalized by DC2.4 DCs and processed via a proteasome-dependent, brefeldin- and cycloheximide-sensitive, chloroquine- and primaquine-insensitive pathway, resulting in loading of the CTL epitope onto H-2K(b). In vivo cross-presentation and cross-priming were efficient, even without adjuvant; injection of mice with 3D8 scFv-OVA(250-264) induced cross-presentation of the CTL epitope by draining lymph node CD11c(+) B7.1(+) MHC class II(high) DCs, elicited a CTL response, and suppressed the growth of tumors expressing the OVA epitope. This report shows that an anti-nucleic acid Ab is used to deliver exogenous Ag to the cross-presentation pathway and inhibit in vivo tumor growth.

[Macroglobulin signaling system]

This review will focus on the systematization of knowledge about structure of macroglobulin signaling system, which includes macroglobulin family proteins (alpha-2-macroglobulin, alpha-2-glycoprotein, pregnancy associated plasma protein A), their receptors (LRP, grp78), ligands (proteinases, cytokines, hormones, lipids, et al.) transforming and transcriptional factors for regulation of macroglobulins synthesis. After reviewing the functions of macroglobulin signaling system, and mechanisms of their realization, we discuss the complex and significant role of this system in different physiological and pathological processes.

Low-dose curcumin leads to the inhibition of tumor growth via enhancing CTL-mediated antitumor immunity

Curcumin, a yellow pigment extracted from turmeric, is widely used to inhibit tumor progression. Since it can either promote or suppress the immune system, how curcumin affects the immune system in tumor-bearing bodies is not yet clear. Our study found that tumor-bearing mice treated consecutively once a day with low-dose curcumin for ten days led to a retarded tumor growth and a longer survival, which might be contributed to T cell-mediated adaptive immune response. The in vitro study also showed that a high-dose curcumin decreases T cells whereas a low-dose increases T cells derived from 3LL tumor-bearing mice, especially CD8+ T cells. Accordingly, these increased CD8+ T cells exhibited the enhancement of IFN-γ secretion, proliferation and cytotoxicity specifically against 3LL tumor cells, which may result in the success of antitumor immunity. Our research demonstrated a beneficial effect of curcumin on CD8+ T cells derived from tumor-bearing mice, which can provide a potential application in anti-tumor therapy.

Re-examination of CD91 function in GRP94 (glycoprotein 96) surface binding, uptake, and peptide cross-presentation

GRP94 (gp96)-peptide complexes can be internalized by APCs and their associated peptides cross-presented to yield activation of CD8(+) T cells. Investigations into the identity (or identities) of GRP94 surface receptors have yielded conflicting results, particularly with respect to CD91 (LRP1), which has been proposed to be essential for GRP94 recognition and uptake. To assess CD91 function in GRP94 surface binding and endocytosis, these parameters were examined in mouse embryonic fibroblast (MEF) cell lines whose expression of CD91 was either reduced via RNA interference or eliminated by genetic disruption of the CD91 locus. Reduction or loss of CD91 expression abrogated the binding and uptake of receptor-associated protein, an established CD91 ligand. Surface binding and uptake of an N-terminal domain of GRP94 (GRP94.NTD) was unaffected. GRP94.NTD surface binding was markedly suppressed after treatment of MEF cell lines with heparin, sodium chlorate, or heparinase II, demonstrating that heparin sulfate proteoglycans can function in GRP94.NTD surface binding. The role of CD91 in the cross-presentation of GRP94-associated peptides was examined in the DC2.4 dendritic cell line. In DC2.4 cells, which express CD91, GRP94.NTD-peptide cross-presentation was insensitive to the CD91 ligands receptor-associated protein or activated α(2)-macroglobulin and occurred primarily via a fluid-phase, rather than receptor-mediated, uptake pathway. These data clarify conflicting data on CD91 function in GRP94 surface binding, endocytosis, and peptide cross-presentation and identify a role for heparin sulfate proteoglycans in GRP94 surface binding.