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Cryptococcus neoformans is included in the World Health Organization fungal priority pathogen list, complied to expedite improved research and public-health interventions. The limited number of available antifungal drugs, their associated toxicity, and the emergence of drug-resistant strains make the development of new therapeutic strategies mandatory. Pattern-recognition receptors (PRRs) from the host's innate immune system constitute a potential source of new antimicrobial agents. CD5 and CD6 are lymphoid members of the ancient scavenger receptor cysteine-rich superfamily (SRCR-SF) which bind pathogen-associated molecular patterns (PAMPs) of fungal and bacterial origin. Evidence supports the concept that such binding maps to 11-mer sequences present in each of their three SRCR extracellular domains. Herein, we have designed synthetic peptides containing tandems of such 11-mer sequences (namely CD5-T and CD6-T) and analyzed their C. neoformans-binding properties in vitro. Our results show both inhibitory effects on fungal growth and an ability to impact capsule formation and titanization, two critical virulence factors of C. neoformans involved in immune evasion. These effects hold promise for CD5-T and CD6-T peptides as single or adjuvant therapeutic agents against cryptococcosis. [ABSTRACT FROM AUTHOR]

Purpose of the Review: Atherosclerotic plaques result from imbalanced lipid metabolism and maladaptive chronic immune responses. Class B scavenger receptors are lipid transporters and regulators of their metabolism. The purpose of this review is to explore recent structural findings of these membrane-associated receptors, with particular focus on their higher-order oligomeric organization and impact on lipid transport. Recent Findings: Class B scavenger receptors have evidence for oligomerization, with recent efforts placed on identifying residues and motifs responsible for mediating this process. The first studies correlating scavenger receptor oligomerization to function are described. Summary: This review highlights two emerging hypotheses regarding the function of scavenger receptor oligomerization. The first is a hydrophobic channel created by self-association of receptors to promote transport. The second hypothesis suggests that homo-oligomerization stabilizes receptors, prevents internalization and thereby promotes transport indirectly. Novel computational and in vitro experimental techniques with purified receptors are also described. [ABSTRACT FROM AUTHOR]

Lipopolysaccharide (LPS) in blood circulation causes endotoxemia and is linked to various disease conditions. Current treatments focus on preventing LPS from interacting with its receptor Toll-like receptor 4 (TLR4) and reducing inflammation. However, our body has a natural defense mechanism: reticuloendothelial cells in the liver rapidly degrade and inactivate much of the circulating LPS within minutes. But this LPS clearance mechanism is not perfect. Excessive LPS that escape this clearance mechanism cause systemic inflammatory damage through TLR4. Despite its importance, the role of reticuloendothelial cells in LPS elimination is not well-studied, especially regarding the specific cells, receptors, and mechanisms involved. This gap hampers the development of effective therapies for endotoxemia and related diseases. This review consolidates the current understanding of LPS clearance, narrates known and explores potential mechanisms, and discusses the relationship between LPS clearance and LPS signaling. It also aims to highlight key insights that can guide the development of strategies to reduce circulating LPS by way of bolstering host defense mechanisms. Ultimately, we seek to provide a foundation for future research that could lead to innovative approaches for enhancing the body's natural ability to clear LPS and thereby lower the risk of endotoxin-related inflammatory diseases, including sepsis. [ABSTRACT FROM AUTHOR]

The influence of chronic diseases on various facets of macrophage cellular senescence is poorly understood. This study evaluated the impact of chronic hyperglycemia on the induction of cellular senescence and subsequent immunosurveillance functions in RAW264.7 macrophages. Macrophages were cultured under normal glucose (NG; 5 mM), high glucose (HG; 20 mM), and very high glucose (VHG; 40 mM) conditions and assessed for markers of cellular senescence. Hyperglycemia induced strong upregulation of SA-β-gal activity, and loss of PCNA and Lamin B1 gene expression while markers of cell cycle arrest generally decreased. Non-significant changes in SASP-related proteins were observed while ROS levels slightly decreased and mitochondrial membrane potential increased. Protein concentration on the exosome membrane surface and their stability appeared to increase under hyperglycemic conditions. However, when macrophages were exposed to the secretory media (SM) of senescent preadipocytes, a dramatic increase in the levels of all inflammatory proteins was recorded especially in the VHG group that was also accompanied by upregulation of NF-κB and NLRP3 gene expression. SM treatment to hyperglycemic macrophages activated the TLR-2/Myd88 pathway but decreased the expression of scavenger receptors RAGE, CD36, and Olr-1 while CD44 and CXCL16 expression increased. On exposure to LPS, a strong upregulation in NO, ROS, and inflammatory cytokines was observed. Together, these results suggest that primary markers of cellular senescence are aberrantly expressed under chronic hyperglycemic conditions in macrophages with no significant SASP activation. Nonetheless, hyperglycemia strongly deregulates macrophage functions leading to impaired immunosurveillance of senescent cells and aggravation of inflamm-aging. This work provides novel insights into how hyperglycemia-induced dysfunctions can impact the potency of macrophages to manage senescent cell burden in aging tissues. [ABSTRACT FROM AUTHOR]

Background and Purpose: Atherosclerosis induced by cyclosporine A (CsA), an inhibitor of the calcineurin/nuclear factor of activated T cells (NFAT) pathway, is a major concern after organ transplantation. However, the atherosclerotic mechanisms of CsA remain obscure. We previously demonstrated that calcineurin/NFAT signalling inhibition contributes to atherogenesis via suppressing microRNA‐204 (miR‐204) transcription. We therefore hypothesised that miR‐204 is involved in the development of CsA‐induced atherosclerosis. Experimental Approach: ApoE−/− mice with macrophage‐miR‐204 overexpression were generated to determine the effects of miR‐204 on CsA‐induced atherosclerosis. Luciferase reporter assays and chromatin immunoprecipitation sequencing were performed to explore the targets mediating miR‐204 effects. Key Results: CsA alone did not significantly affect atherosclerotic lesions or serum lipid levels. However, it exacerbated high‐fat diet‐induced atherosclerosis and hyperlipidemia in C57BL/6J and ApoE−/− mice, respectively. miR‐204 levels decreased in circulating monocytes and plaque lesions during CsA‐induced atherosclerosis. The upregulation of miR‐204 in macrophages inhibited CsA‐induced atherosclerotic plaque formation but did not affect serum lipid levels. miR‐204 limited the CsA‐induced foam cell formation by reducing the expression of the scavenger receptors SR‐BII and CD36. SR‐BII was post‐transcriptionally regulated by mature miR‐204‐5p via 3′‐UTR targeting. Additionally, nuclear‐localised miR‐204‐3p prevented the CsA‐induced binding of Ago2 to the CD36 promoter, suppressing CD36 transcription. SR‐BII or CD36 expression restoration dampened the beneficial effects of miR‐204 on CsA‐induced atherosclerosis. Conclusion and Implications: Macrophage miR‐204 ameliorates CsA‐induced atherosclerosis, suggesting that miR‐204 may be a potential target for the prevention and treatment of CsA‐related atherosclerotic side effects. [ABSTRACT FROM AUTHOR]

Cryptococcus neoformans is included in the World Health Organization fungal priority pathogen list, complied to expedite improved research and public-health interventions. The limited number of available antifungal drugs, their associated toxicity, and the emergence of drug-resistant strains make the development of new therapeutic strategies mandatory. Pattern-recognition receptors (PRRs) from the host’s innate immune system constitute a potential source of new antimicrobial agents. CD5 and CD6 are lymphoid members of the ancient scavenger receptor cysteine-rich superfamily (SRCR-SF) which bind pathogen-associated molecular patterns (PAMPs) of fungal and bacterial origin. Evidence supports the concept that such binding maps to 11-mer sequences present in each of their three SRCR extracellular domains. Herein, we have designed synthetic peptides containing tandems of such 11-mer sequences (namely CD5-T and CD6-T) and analyzed their C. neoformans-binding properties in vitro. Our results show both inhibitory effects on fungal growth and an ability to impact capsule formation and titanization, two critical virulence factors of C. neoformans involved in immune evasion. These effects hold promise for CD5-T and CD6-T peptides as single or adjuvant therapeutic agents against cryptococcosis.

Lipopolysaccharide (LPS) in blood circulation causes endotoxemia and is linked to various disease conditions. Current treatments focus on preventing LPS from interacting with its receptor Toll-like receptor 4 (TLR4) and reducing inflammation. However, our body has a natural defense mechanism: reticuloendothelial cells in the liver rapidly degrade and inactivate much of the circulating LPS within minutes. But this LPS clearance mechanism is not perfect. Excessive LPS that escape this clearance mechanism cause systemic inflammatory damage through TLR4. Despite its importance, the role of reticuloendothelial cells in LPS elimination is not well-studied, especially regarding the specific cells, receptors, and mechanisms involved. This gap hampers the development of effective therapies for endotoxemia and related diseases. This review consolidates the current understanding of LPS clearance, narrates known and explores potential mechanisms, and discusses the relationship between LPS clearance and LPS signaling. It also aims to highlight key insights that can guide the development of strategies to reduce circulating LPS by way of bolstering host defense mechanisms. Ultimately, we seek to provide a foundation for future research that could lead to innovative approaches for enhancing the body’s natural ability to clear LPS and thereby lower the risk of endotoxin-related inflammatory diseases, including sepsis.

Cancer management still requires more potent and safer treatments, of which immunomodulatory receptors on the lymphocyte surface have started to show promise in new cancer immunotherapies (e.g., CTLA-4 and PD-1). CD6 is a signal-transducing transmembrane receptor, mainly expressed by all T cells and some B and NK cell subsets, whose endogenous ligands (CD166/ALCAM, CD318/CDCP-1, Galectins 1 and 3) are overexpressed by malignant cells of different lineages. This places CD6 as a potential target for novel therapies against haematological and non-haematological malignancies. Recent experimental evidence for the role of CD6 in cancer immunotherapies is summarised in this review, dealing with diverse and innovative strategies from the classical use of monoclonal antibodies to soluble recombinant decoys or the adoptive transfer of immune cells engineered with chimeric antigen receptors. [ABSTRACT FROM AUTHOR]

Stabilin‐1 (Stab1) and Stabilin‐2 (Stab2) are two major scavenger receptors of liver sinusoidal endothelial cells that mediate removal of diverse molecules from the plasma. Double‐knockout mice (Stab‐DKO) develop impaired kidney function and a decreased lifespan, while single Stabilin deficiency or therapeutic inhibition ameliorates atherosclerosis and Stab1‐inhibition is subject of clinical trials in immuno‐oncology. Although POSTN and TFGBI have recently been described as novel Stabilin ligands, the dynamics and functional implications of these ligands have not been comprehensively studied. Immunofluorescence, Western Blotting and Simple Western™ as well as in situ hybridization (RNAScope™) and qRT‐PCR were used to analyze transcription levels and tissue distribution of POSTN and TGFBI in Stab‐KO mice. Stab‐POSTN‐Triple deficient mice were generated to assess kidney and liver fibrosis and function in young and aged mice. TGFBI and POSTN protein accumulated in liver tissue in Stab‐DKO mice and age‐dependent in glomeruli of Stabilin‐deficient mice despite unchanged transcriptional levels. Stab‐POSTN‐Triple KO mice showed glomerulofibrosis and a reduced lifespan comparable to Stab‐DKO mice. However, alterations of the glomerular diameter and vascular density were partially normalized in Stab‐POSTN‐Triple KO. TGFBI and POSTN are Stabilin‐ligands that are deposited in an age‐dependent manner in the kidneys and liver due to insufficient scavenging in the liver. Functionally, POSTN might partially contribute to the observed renal phenotype in Stab‐DKO mice. This study provides details on downstream effects how Stabilin dysfunction affects organ function on a molecular and functional level. [ABSTRACT FROM AUTHOR]

Atherosclerotic plaques develop from the accumulation of macrophage-derived foam cells via the uptake of modified low-density lipoprotein (LDL). CD36 and CD204 are the principal scavenger receptors responsible for the uptake of modified LDL. Although glucocorticoids are suspected to exacerbate atherosclerosis, the precise mechanisms have not been fully elucidated. We investigated the effects of long-term treatment (2 weeks) with both a natural glucocorticoid (hydrocortisone, HC, 1 μM) and a synthetic glucocorticoid (dexamethasone, Dex, 100 nM) on murine bone marrow-derived macrophages using flow cytometry and western blotting. Treatment with HC and Dex enhanced CD204 expression but not CD36 expression and acetylated LDL (Ac-LDL) uptake. Treatment with HC and Dex also induced the phosphorylation of extracellular signal-regulated kinase (ERK). The Dex-induced enhancement in CD204 expression and Ac-LDL uptake were suppressed by an inhibitor of the mitogen-activated protein kinase (MAPK)/ERK kinase. These results suggest that glucocorticoids activate the MAPK/ERK pathway, which enhances CD204 expression and results in increased uptake of Ac-LDL in macrophages. The MAPK/ERK pathway in macrophages might be a key target to prevent atherosclerosis that is worsened by glucocorticoids.

Production of nitric oxide (NO) by LPS-activated macrophages is due to a complex cellular signaling initiated by TLR4 that leads to the transcription of IFN-β, which activates IRF-1 and STAT-1, as well as to the activation of NF-κB, required for iNOS transcription. High concentrations of LPS can also be uptaken by scavenger receptors (SRs), which, in concert with TLR4, leads to inflammatory responses. The mechanisms by which TLR4 and SRs interact, and the pathways activated by this interaction in macrophages are not elucidated. Therefore, our main goal was to evaluate the role of SRs, particularly SR-A, in LPS-stimulated macrophages for NO production. We first showed that, surprisingly, LPS can induce the expression of iNOS and the production of NO in TLR4−/− mice, provided exogenous IFN-β is supplied. These results indicate that LPS stimulate receptors other than TLR4. The inhibition of SR-A using DSS or neutralizing antibody to SR-AI showed that SR-A is essential for the expression of iNOS and NO production in stimulation of TLR4 by LPS. The restoration of the ability to express iNOS and produce NO by addition of rIFN-β to inhibited SR-A cells indicated that the role of SR-AI in LPS-induced NO production is to provide IFN-β, probably by mediating the internalization of LPS/TLR4, and the differential inhibition by DSS and neutralizing antibody to SR-AI suggested that other SRs are also involved. Our results reinforce that TLR4 and SR-A act in concert in LPS activation and demonstrated that, for the production of NO, it does mainly by synthesizing IRF-3 and also by activating the TRIF/IRF-3 pathway for IFN-β production, essential for LPS-mediated transcription of iNOS. Consequently STAT-1 is activated, and IRF-1 is expressed, which together with NF-κB from TLR4/MyD88/TIRAP, induce iNOS synthesis and NO production. TLR4 and SRs act in concert activating IRF-3 to transcribe IFN-β and activate STAT-1 to produce NO by LPS-activated macrophages. • LPS-activated TLR4-deficient cells are able to produce NO provided IFN-β is supplied. • SRs are indispensable for TLR4-mediated NO production in macrophages. • SR-AI acts in concert with TLR4 to internalize LPS and activate TRIF/IRF-3 pathway. • SR-AI is needed for TLR4-mediated expression of IFN-β, crucial for iNOS expression. • SR-AI is needed for activation of STAT-1 and expression of IRF-1, crucial for iNOS expression. [ABSTRACT FROM AUTHOR]

An active form of cathelicidin antimicrobial peptide, LL-37, has immunomodulatory and stimulatory effects, though the specific pathways are not clear. The purpose of this study was to identify the cellular pathways by which LL-37 amplifies the inflammation induced by damage-associated molecular patterns (DAMPs). We performed DNA microarray, reverse transcription polymerase chain reaction, immunoblotting, and proximity ligation assays using cultured keratinocytes treated with LL-37 and/or the DAMP poly(I:C), a synthetic double-stranded RNA. In contrast to the combination of LL-37 and poly(I:C), LL-37 alone induced genes related to biological metabolic processes such as VEGFA and PTGS2 (COX-2). Inhibition of FPR2, a known receptor for cathelicidin, partially suppressed the induction of VEGFA and PTGS2. Importantly, VEGFA and PTGS2 induced by LL-37 alone were diminished by the knockdown of scavenger receptors including SCARB1 (SR-B1), OLR1 (SR-E1), and AGER (SR-J1). Moreover, LL-37 alone, as well as the combination of LL-37 and poly(I:C), showed proximity to the scavenger receptors, indicating that LL-37 acts via scavenger receptors and intermediates between them and poly(I:C). These results showed that the broad function of cathelicidin is generally dependent on scavenger receptors. Therefore, inhibitors of scavenger receptors or non-functional mock cathelicidin peptides may serve as new anti-inflammatory and immunosuppressive agents. [ABSTRACT FROM AUTHOR]

Atherosclerosis is a chronic inflammation characterized by macrophage infiltration, lipid deposition, and arterial wall thickening. Prevention of atherosclerosis by nutraceuticals is gaining attention. Myricetin, a dietary flavonol, is claimed to possess anti-atherosclerosis properties. We studied myricetin's effect on the atherosclerosis-associated molecular mechanism. Cytotoxicity and proliferation testing to check the viability of myricetin-treated THP-1 macrophages and monocyte migration study in the presence and absence of myricetin was performed. The whole transcriptome analysis was conducted using the Affymetrix microarray platform. The Partek genomics suite for detecting differentially expressed genes (DEGs) and ingenuity pathway analysis was used to identify canonical pathways. Cytotoxicity assays exhibited no significant toxicity in THP-1 macrophages treated with different myricetin concentrations (10–200 μM). Genome-wide expression profiling revealed 58 DEGs (53 upregulated and 5 downregulated) in myricetin-treated THP-1 macrophages. Pathway analysis revealed inhibition of LXR/RXR activation and angiogenesis inhibition by thrombospondin-1 and activated phagocytosis in myricetin-treated THP-1 macrophages. The cytotoxicity assay shows myricetin as a safe phytochemical. In vitro and in silico pathway studies on THP-1 macrophages showed that they can inhibit THP-1 monocyte migration and alter the cholesterol efflux mediated via LXR/RXR signaling. Therefore, myricetin could help in the prevention of cell infiltration in atherosclerotic plaque with reduced risk of stroke or brain damage. [ABSTRACT FROM AUTHOR]

Abstract Scavenger receptors belong to a superfamily of proteins that are structurally heterogeneous and encompass the miscellaneous group of transmembrane proteins and soluble secretory extracellular domain. They are functionally diverse as they are involved in various disorders and biological pathways and their major function in innate immunity and homeostasis. Numerous scavenger receptors have been discovered so far and are apportioned in various classes (A-L). Scavenger receptors are documented as pattern recognition receptors and known to act in coordination with other co-receptors such as Toll-like receptors in generating the immune responses against a repertoire of ligands such as microbial pathogens, non-self, intracellular and modified self-molecules through various diverse mechanisms like adhesion, endocytosis and phagocytosis etc. Unlike, most of the scavenger receptors discussed below have both membrane and soluble forms that participate in scavenging; the role of a potential scavenging receptor Angiotensin-Converting Enzyme-2 has also been discussed whereby only its soluble form might participate in preventing the pathogen entry and replication, unlike its membrane-bound form. This review majorly gives an insight on the functional aspect of scavenger receptors in host defence and describes their mode of action extensively in various immune pathways involved with each receptor type. Video abstract

An ability of poorly differentiated cells of different genesis, including tumor stem-like cells (TSCs), to internalize extracellular double-stranded DNA (dsDNA) fragments was revealed in our studies. Using the models of Krebs-2 murine ascites carcinoma and EBV-induced human B-cell lymphoma culture, we demonstrated that dsDNA internalization into the cell consists of several mechanistically distinct phases. The primary contact with cell membrane factors is determined by electrostatic interactions. Firm contacts with cell envelope proteins are then formed, followed by internalization into the cell of the complex formed between the factor and the dsDNA probe bound to it. The key binding sites were found to be the heparin-binding domains, which are constituents of various cell surface proteins of TSCs—either the C1q domain, the collagen-binding domain, or domains of positively charged amino acids. These results imply that the interaction between extracellular dsDNA fragments and the cell, as well as their internalization, took place with the involvement of glycocalyx components (proteoglycans/glycoproteins (PGs/GPs) and glycosylphosphatidylinositol-anchored proteins (GPI-APs)) and the system of scavenger receptors (SRs), which are characteristic of TSCs and form functional clusters of cell surface proteins in TSCs. The key provisions of the concept characterizing the principle of organization of the "group-specific" cell surface factors of TSCs of various geneses were formulated. These factors belong to three protein clusters: GPs/PGs, GIP-APs, and SRs. For TSCs of different tumors, these clusters were found to be represented by different members with homotypic functions corresponding to the general function of the cluster to which they belong. [ABSTRACT FROM AUTHOR]

Scavenger receptors are part of a complex surveillance system expressed by host cells to efficiently orchestrate innate immune response against bacterial infections. Stabilin-1 (STAB-1) is a scavenger receptor involved in cell trafficking, inflammation, and cancer; however, its role in infection remains to be elucidated. Listeria monocytogenes (Lm) is a major intracellular human food-borne pathogen causing severe infections in susceptible hosts. Using a mouse model of infection, we demonstrate here that STAB-1 controls Lm-induced cytokine and chemokine production and immune cell accumulation in Lm-infected organs. We show that STAB-1 also regulates the recruitment of myeloid cells in response to Lm infection and contributes to clear circulating bacteria. In addition, whereas STAB-1 appears to promote bacterial uptake by macrophages, infection by pathogenic Listeria induces the down regulation of STAB-1 expression and its delocalization from the host cell membrane. We propose STAB-1 as a new SR involved in the control of Lm infection through the regulation of host defense mechanisms, a process that would be targeted by bacterial virulence factors to promote infection.

Background and Objectives: Cardiovascular (CV) risk is elevated in rheumatoid arthritis (RA). RA patient plasma causes pro-atherogenic derangements in cholesterol transport leading to macrophage foam cell formation (FCF). The TARGET randomized clinical trial compares CV benefits of 2 RA drug regimens. Hydoxychloroquine (HCQ) is a key medication used in TARGET. This study examines effects of HCQ on lipid transport to elucidate mechanisms underlying TARGET outcomes and as an indicator of likely HCQ effects on atherosclerosis in RA. Materials and Methods: THP1 human macrophages were exposed to media alone, IFNγ (atherogenic cytokine), HCQ, or HCQ + IFNγ. Cholesterol efflux protein and scavenger receptor mRNA levels were quantified by qRT-PCR and corresponding protein levels were assessed by Western blot. FCF was evaluated via Oil-Red-O and fluorescent-oxidized LDL. Intracellular cholesterol and efflux were quantified with Amplex Red assay. Results: With the exception of a decrease in the efflux protein cholesterol 27-hydroxylase in the presence IFNγ at all HCQ concentrations, no significant effect on gene or protein expression was observed upon macrophage exposure to HCQ and this was reflected in the lack of change in FCF and oxidized LDL uptake. Conclusions: HCQ did not significantly affect THP1 macrophage cholesterol transport. This is consistent with TARGET, which postulates superior effects of anti-TNF agents over sulfasalazine + HCQ. [ABSTRACT FROM AUTHOR]

The study aimed to achieve enhanced targeted cytotoxicity and cell-internalization of cisplatin-loaded deoxyribonucleic acid-nanothread (CPT-DNA-NT), mediated by scavenger receptors into HeLa cells. DNA-NT was developed with stiff-topology utilizing circular-scaffold to encapsulate CPT. Atomic force microscopy (AFM) characterization of the DNA-NT showed uniformity in the structure with a diameter of 50–150 nm and length of 300–600 nm. The successful fabrication of the DNA-NT was confirmed through native-polyacrylamide gel electrophoresis analysis, as large the molecular-weight (polymeric) DNA-NT did not split into constituting strands under applied current and voltage. The results of cell viability confirmed that blank DNA-NT had the least cytotoxicity at the highest concentration (512 nM) with a viability of 92% as evidence of its biocompatibility for drug delivery. MTT assay showed superior cytotoxicity of CPT-DNA-NT than that of the free CPT due to the depot release of CPT after DNA-NT internalization. The DNA-NT exhibited targeted cell internalizations with the controlled intracellular release of CPT (from DNA-NT), as illustrated in confocal images. Therefore, in vitro cytotoxicity assessment through flow cytometry showed enhanced apoptosis (72.7%) with CPT-DNA-NT (compared to free CPT; 64.4%). CPT-DNA-NT, being poly-anionic, showed enhanced endocytosis via scavenger receptors.

DNA-nanotechnology-based nano-architecture scaffolds based on circular strands were designed in the form of DNA-nanowires (DNA-NWs) as a polymer of DNA-triangles. Circularizing a scaffold strand (84-NT) was the critical step followed by annealing with various staple strands to make stiff DNA-triangles. Atomic force microcopy (AFM), native polyacrylamide gel electrophoresis (PAGE), UV-analysis, MTT-assay, flow cytometry, and confocal imaging were performed to assess the formulated DNA-NWs and cisplatin (CPT) loading. The AFM and confocal microscopy images revealed a uniform shape and size distribution of the DNA-NWs, with lengths ranging from 2 to 4 μm and diameters ranging from 150 to 300 nm. One sharp band at the top of the lane (500 bp level) with the loss of electrophoretic mobility during the PAGE (native) gel analysis revealed the successful fabrication of DNA-NWs. The loading efficiency of CPT ranged from 66.85% to 97.35%. MTT and flow cytometry results showed biocompatibility of the blank DNA-NWs even at 95% concentration compared with the CPT-loaded DNA-NWs. The CPT-loaded DNA-NWs exhibited enhanced apoptosis (22%) compared to the apoptosis (7%) induced by the blank DNA-NWs. The release of CPT from the DNA-NWs was sustained at < 75% for 6 h in the presence of serum, demonstrating suitability for systemic applications. The IC50 of CPT@DNA-NWs was reduced to 12.8 nM CPT, as compared with the free CPT solution exhibiting an IC50 of 51.2 nM. Confocal imaging revealed the targetability, surface binding, and slow internalization of the DNA-NWs in the scavenger-receptor-rich cancer cell line (HepG2) compared with the control cell line.

The scavenger receptors (SRs) gene family is considered as the membrane-associated pattern recognition receptors that plays important roles in the immune responses of organisms. However, there is currently limited research on the systematic identification of the SRs gene family in teleost and their role in the innate immunity of S. schegelii. In this study, we identified and annotated 15 SRs genes in S. schegelii. Through phylogenetic analysis, analysis of conserved domains, gene structure, and motif composition, we found that SRs gene family within different classes were relatively conserved. Additionally, we used qRT-PCR to analyze the expression patterns of SRs genes in immune-related tissues from healthy and Acinetobacter johnsonii -infected S. schegelii. The results showed that SRs genes exhibited different tissue expression patterns and the expression of SRs genes significantly changed after A. johnsonii infection. These results provided a valuable basis for further understanding of the functions of SRs in the innate immune response of S. schegelii. • 15 SRs genes from eight classes were identified for the first time in black rockfish (Sebastes schlegelii). • Revealed the relative conservatism of the SRs gene family in Sebastes schlegelii. • SRs genes exhibited different tissue expression patterns. • The expression of some SRs genes significantly changed after Acinetobacter johnsonii infection. [ABSTRACT FROM AUTHOR]

Deposition of fibrillar forms of amyloid β-protein (Aβ) is commonly found in patients with Alzheimer's disease (AD) associated with cognitive decline. Impaired clearance of Aβ species is thought to be a major cause of late-onset sporadic AD. Aβ secreted into the extracellular milieu can be cleared from the brain through multiple pathways, including cellular uptake in neuronal and non-neuronal cells. Recent studies have showed that the naturally-occurring polyphenol amentoflavone (AMF) exerts anti-amyloidogenic effects. However, its effects on metabolism and cellular clearance of Aβ remain to be tested. In the present study, we demonstrated that AMF significantly increased the cellular uptake of both Aβ1-40 and Aβ1-42, but not inverted Aβ42-1 in mouse neuronal N2a cells. Though AMF promoted internalization of cytotoxic Aβ1-42, it significantly reduced cell death in our assay condition. Our data further revealed that the internalized Aβ is translocated to lysosomes and undergoes enzymatic degradation. The saturable kinetic of Aβ uptake and our pharmacologic experiments showed the involvement of receptor-mediated endocytosis, in part, through the class A scavenger receptors as a possible mechanism of action of AMF. Taken together, our findings indicate that AMF can lower the levels of extracellular Aβ by increasing their cellular uptake and clearance, suggesting the therapeutic potential of AMF for the treatment of AD. [ABSTRACT FROM AUTHOR]

Oxidative stress and inflammation cannot be considered as diseases themselves; however, they are major risk factors for the development and progression of the pathogenesis underlying many illnesses, such as cancer, neurological disorders (including Alzheimer's disease and Parkinson's disease), autoimmune and metabolic disorders, etc. According to the results obtained from extensive studies, oxidative stress–induced biomolecules, such as advanced oxidation protein products, advanced glycation end products, and advanced lipoxidation end products, are critical for an accelerated level of inflammation and oxidative stress–induced cellular damage, as reflected in their strong affinity to a wide range of scavenger receptors. Based on the limitations of antioxidative and anti-inflammatory molecules in practical applications, targeting such interactions between harmful molecules and their cellular receptors/signaling with advances in gene engineering technology, such as CRISPR or TALEN, may prove to be a safe and effective alternative. In this review, we summarize the findings of recent studies focused on the deletion of scavenger receptors under oxidative stress as a development in the therapeutic approaches against the diseases linked to inflammation and the contribution of advanced glycation end products (AGEs), advanced lipid peroxidation products (ALEs), and advanced oxidation protein products (AOPPs). [ABSTRACT FROM AUTHOR]

Scavenger receptors (SR) are not only pattern recognition receptors involved in the immune response against pathogens but are also important receptors exploited by different virus to enter host cells, and thus represent targets for antiviral therapy. The high mutation rates of viruses, as well as their small genomes are partly responsible for the high rates of virus resistance and effective treatments remain a challenge. Most currently approved formulations target viral-encoded factors. Nevertheless, host proteins may function as additional targets. Thus, there is a need to explore and develop new strategies aiming at cellular factors involved in virus replication and host cell entry. SR-virus interactions have implications in the pathogenesis of several viral diseases and in adenovirus-based vaccination and gene transfer technologies, and may function as markers of severe progression. Inhibition of SR could reduce adenoviral uptake and improve gene therapy and vaccination, as well as reduce pathogenesis. In this review, we will examine the crucial role of SR play in cell entry of different types of human virus, which will allow us to further understand their role in protection and pathogenesis and its potential as antiviral molecules. The recent discovery of SR-B1 as co-factor of SARS-Cov-2 (severe acute respiratory syndrome coronavirus 2) entry is also discussed. Further fundamental research is essential to understand molecular interactions in the dynamic virus-host cell interplay through SR for rational design of therapeutic strategies. [ABSTRACT FROM AUTHOR]

The retinal phagocytic machinery resembles the one used by macrophages to clear apoptotic cells. However, in the retina, the permanent contact between photoreceptor outer segments (POS) and retinal pigment epithelial (RPE) cells requires a tight control of this circadian machinery. In addition to the known receptors synchronizing POS internalization, several others are expressed by RPE cells. Notably, scavenger receptor CD36 has been shown to intervene in the internalization speed. We thus investigated members of the scavenger receptor family class A SR-AI and MARCO and class B CD36, SR-BI and SR-B2/LIMP-2 using immunoblotting, immunohisto- and immunocytochemistry, lipid raft flotation gradients, phagocytosis assays after siRNA/antibody inhibition, RT-qPCR and western blot analysis along the light:dark cycle. All receptors were expressed by RPE cell lines and tissues and colocalized with POS, except SR-BI. All receptors were associated with lipid rafts, and even more upon POS challenge. SR-B2/LIMP-2 inhibition suggested a role in the control of the internalization speed similar to CD36. In vivo, MARCO and CD36 displayed rhythmic gene and protein expression patterns concomitant with the phagocytic peak. Taken together, our results indicate that CD36 and SR-B2/LIMP-2 play a direct regulatory role in POS phagocytosis dynamics, while the others such as MARCO might participate in POS clearance by RPE cells either as co-receptors or via an indirect process. [ABSTRACT FROM AUTHOR]

Scavenger receptors form a superfamily of membrane-bound receptors that bind and internalize different types of ligands, including pro-atherogenic oxidized low-density lipoproteins (oxLDLs). In vitro studies have indicated a role for the liver sinusoidal endothelial cell receptors stabilin 1 (stab1) and 2 (stab2) in oxLDL clearance. In this study, we evaluated the potential role of stab1 and stab2 in lipoprotein uptake in zebrafish, an upcoming model for studying cholesterol metabolism and atherosclerosis. Lipoproteins were injected in the duct of Cuvier of wild-type (ABTL) or stab1 and stab2 mutant (stab1 −/− stab2 −/−) zebrafish larvae at 3 days post-fertilization. To examine the effect of stabilin deficiency on lipoprotein and cholesterol metabolism, zebrafish larvae were challenged with a high cholesterol diet (HCD; 4% w/w) for 10 days. Lipoprotein injections showed impaired uptake of both LDL and oxLDL into the vessel wall of caudal veins of stab1 −/− stab2 −/− zebrafish, which was paralleled by redistribution to tissue macrophages. Total body cholesterol levels did not differ between HCD-fed stab1 −/− stab2 −/− and ABTL zebrafish. However, stab1 −/− stab2 −/− larvae exhibited 1.4-fold higher mRNA expression levels of ldlra involved in (modified) LDL uptake, whereas the expression levels of scavenger receptors scarb1 and cd36 were significantly decreased. We have shown that stabilins 1 and 2 have an important scavenging function for apolipoprotein B-containing lipoproteins in zebrafish and that combined deficiency of these two proteins strongly upregulates the clearance of lipoproteins by macrophages within the caudal vein. Our current study highlights the use of zebrafish as model to study lipoprotein metabolism and liver sinusoidal endothelial cell function. [Display omitted] • Stabilin 1 and 2 are key players in zebrafish lipoprotein metabolism. • Stabilin 1 and 2 double deficiency induces macrophage oxidized low-density lipoproteins (oxLDLs) uptake in zebrafish. • Stabilin 1/2 double knockout zebrafish are resistant to vascular lipid deposition. • Zebrafish are a good model to study liver sinusoidal endothelial cell function. [ABSTRACT FROM AUTHOR]

The scavenger receptor superfamily represents a highly diverse collection of evolutionarily-conserved receptors which are known to play key roles in host homeostasis, the most prominent of which is the clearance of unwanted endogenous macromolecules, such as oxidized low-density lipoproteins, from the systemic circulation. Members of this family have also been well characterized in their binding and internalization of a vast range of exogenous antigens and, consequently, are generally considered to be pattern recognition receptors, thus contributing to innate immunity. Several studies have implicated scavenger receptors in the pathophysiology of several inflammatory diseases, such as Alzheimer's and atherosclerosis. Hepatic resident cellular populations express a diverse complement of scavenger receptors in keeping with the liver's homeostatic functions, but there is gathering interest in the contribution of these receptors to hepatic inflammation and its complications. Here, we review the expression of scavenger receptors in the liver, their functionality in liver homeostasis, and their role in inflammatory liver disease and cancer. [ABSTRACT FROM AUTHOR]

Scavenger receptors belong to a superfamily of proteins that are structurally heterogeneous and encompass the miscellaneous group of transmembrane proteins and soluble secretory extracellular domain. They are functionally diverse as they are involved in various disorders and biological pathways and their major function in innate immunity and homeostasis. Numerous scavenger receptors have been discovered so far and are apportioned in various classes (A-L). Scavenger receptors are documented as pattern recognition receptors and known to act in coordination with other co-receptors such as Toll-like receptors in generating the immune responses against a repertoire of ligands such as microbial pathogens, non-self, intracellular and modified self-molecules through various diverse mechanisms like adhesion, endocytosis and phagocytosis etc. Unlike, most of the scavenger receptors discussed below have both membrane and soluble forms that participate in scavenging; the role of a potential scavenging receptor Angiotensin-Converting Enzyme-2 has also been discussed whereby only its soluble form might participate in preventing the pathogen entry and replication, unlike its membrane-bound form. This review majorly gives an insight on the functional aspect of scavenger receptors in host defence and describes their mode of action extensively in various immune pathways involved with each receptor type. 3f-xEqHrhf6veVkmRMaLjV Video abstract [ABSTRACT FROM AUTHOR]

Abstract Functional kleptoplasty is a photosymbiotic relationship, in which photosynthetically active chloroplasts serve as an intracellular symbiont for a heterotrophic host. Among Metazoa, functional kleptoplasty is only found in marine sea slugs belonging to the Sacoglossa and recently described in Rhabdocoela worms. Although functional kleptoplasty has been intensively studied in Sacoglossa, the fundamentals of the specific recognition of the chloroplasts and their subsequent incorporation are unknown. The key to ensure the initiation of any symbiosis is the ability to specifically recognize the symbiont and to differentiate a symbiont from a pathogen. For instance, in photosymbiotic cnidarians, several studies have shown that the host innate immune system, in particular scavenger receptors (SRs) and thrombospondin‐type‐1 repeat (TSR) protein superfamily, is playing a major role in the process of recognizing and differentiating symbionts from pathogens. In the present study, SRs and TSRs of three Sacoglossa sea slugs, Elysia cornigera, Elysia timida, and Elysia chlorotica, were identified by translating available transcriptomes into potential proteins and searching for receptor specific protein and/or transmembrane domains. Both receptors classes are highly diverse in the slugs, and many new domain arrangements for each receptor class were found. The analyses of the gene expression of these three species provided a set of species‐specific candidate genes, that is, SR‐Bs, SR‐Es, C‐type lectins, and TSRs, that are potentially relevant for the recognition of kleptoplasts. The results set the base for future experimental studies to understand if and how these candidate receptors are indeed involved in chloroplast recognition.

Aims Our previous study demonstrated that Ca2+ influx through the Orai1 store-operated Ca2+ channel in macrophages contributes to foam cell formation and atherosclerosis via the calcineurin–ASK1 pathway, not the classical calcineurin–nuclear factor of activated T-cell (NFAT) pathway. Moreover, up-regulation of NFATc3 in macrophages inhibits foam cell formation, suggesting that macrophage NFATc3 is a negative regulator of atherogenesis. Hence, this study investigated the precise role of macrophage NFATc3 in atherogenesis. Methods and results Macrophage-specific NFATc3 knockout mice were generated to determine the effect of NFATc3 on atherosclerosis in a mouse model of adeno-associated virus-mutant PCSK9 -induced atherosclerosis. NFATc3 expression was decreased in macrophages within human and mouse atherosclerotic lesions. Moreover, NFATc3 levels in peripheral blood mononuclear cells from atherosclerotic patients were negatively associated with plaque instability. Furthermore, macrophage-specific ablation of NFATc3 in mice led to the atherosclerotic plaque formation, whereas macrophage-specific NFATc3 transgenic mice exhibited the opposite phenotype. NFATc3 deficiency in macrophages promoted foam cell formation by potentiating SR-A- and CD36-meditated lipid uptake. NFATc3 directly targeted and transcriptionally up-regulated miR-204 levels. Mature miR-204-5p suppressed SR-A expression via canonical regulation. Unexpectedly, miR-204-3p localized in the nucleus and inhibited CD36 transcription. Restoration of miR-204 abolished the proatherogenic phenotype observed in the macrophage-specific NFATc3 knockout mice, and blockade of miR-204 function reversed the beneficial effects of NFATc3 in macrophages. Conclusion Macrophage NFATc3 up-regulates miR-204 to reduce SR-A and CD36 levels, thereby preventing foam cell formation and atherosclerosis, indicating that the NFATc3/miR-204 axis may be a potential therapeutic target against atherosclerosis. [ABSTRACT FROM AUTHOR]

Scavenger receptors are part of a complex surveillance system expressed by host cells to efficiently orchestrate innate immune response against bacterial infections. Stabilin-1 (STAB-1) is a scavenger receptor involved in cell trafficking, inflammation, and cancer; however, its role in infection remains to be elucidated. Listeria monocytogenes (Lm) is a major intracellular human food-borne pathogen causing severe infections in susceptible hosts. Using a mouse model of infection, we demonstrate here that STAB-1 controls Lm-induced cytokine and chemokine production and immune cell accumulation in Lm-infected organs. We show that STAB-1 also regulates the recruitment of myeloid cells in response to Lm infection and contributes to clear circulating bacteria. In addition, whereas STAB-1 appears to promote bacterial uptake by macrophages, infection by pathogenic Listeria induces the down regulation of STAB-1 expression and its delocalization from the host cell membrane. We propose STAB-1 as a new SR involved in the control of Lm infection through the regulation of host defense mechanisms, a process that would be targeted by bacterial virulence factors to promote infection. [ABSTRACT FROM AUTHOR]

• Silica nanoparticles (SiNP) induce IL-6, CXCL8, IL-1α and IL-1β and TGF-α responses in epithelial lung cells. • The scavenger-receptors SR-B1, LOX-1 and CXCL16 are involved in the SiNP-induced cytokine and TGF-α responses. • The SR-B1-induced responses are mediated via MAP-kinase- and NF-κB-independent mechanisms. A major challenge in nanoparticle (NP) research is to elucidate how NPs activate initial targets in cells, leading to cytotoxicity and inflammation. We have previously shown that silica (Si)NPs induce pro-inflammatory responses in bronchial epithelial cells (BEAS-2B) via mechanisms involving transforming growth factor (TGF)-α release, and activation of MAP-kinase p38 and JNK besides NF-κB (p65). In the present study, the roles of scavenger receptors (SRs) in SiNP-induced cytokine responses in BEAS-2B cells were examined by siRNA silencing. Cells exposed to Si10 and Si50 (nominal sizes 10 and 50 nm) showed marked interleukin (IL)-6, CXCL8, IL-1α, IL-1β responses. Transient knockdown of SR-B1, LOX-1 and CXCL16 reduced the Si10- and Si50-induced cytokine responses, to a different magnitude dependent on the particle size, SR and cytokine. Si10-induced TGF-α responses were also markedly reduced by knockdown of SR-B1 and CXCL16. Furthermore, the role of SR-B1 in Si10-induced phosphorylations of p65 and MAP-kinases p38 and JNK were examined, and no significant reductions were observed upon knockdown of SR-B1. In conclusion, LOX-1 and CXCL16 and especially SR-B1 seem to have important roles in mediating cytokine responses and TGF-α release due to SiNP exposure in BEAS-2B cells, without a down-stream role of MAP-kinase and NF-κB. [ABSTRACT FROM AUTHOR]

Scavenger receptors are pattern recognition receptors that recognize both foreign and self-ligands, and initiate different mechanisms of cellular activation, often as co-receptors. The function of scavenger receptor CD36 in the immune system has mostly been studied in macrophages but it is also highly expressed by innate type B cells where its function is less explored. Here we report that CD36 is involved in macro-autophagy/autophagy in B cells, and in its absence, the humoral immune response is impaired. We found that CD36-deficient B cells exhibit a significantly reduced plasma cell formation, proliferation, mitochondrial mobilization and oxidative phosphorylation. These changes were accompanied by impaired initiation of autophagy, and we found that CD36 regulated autophagy and colocalized with autophagosome membrane protein MAP1LC3/LC3 (microtubule-associated protein 1 light chain 3). When we investigated T-cell-dependent immune responses, we found that mice with CD36 deficiency, specifically in B cells, exhibited attenuated germinal center responses, class switching, and antibody production as well as autophagosome formation. These findings establish a critical role for CD36 in B cell responses and may also contribute to our understanding of CD36-mediated autophagy in other cells as well as in B cell lymphomas that have been shown to express the receptor. Abbreviations: AICDA/AID: activation-induced cytidine deaminase; ATG5: autophagy related 5; ATP: adenosine triphosphate; BCR: B-cell receptor; CPG: unmethylated cytosine-guanosine; CQ: chloroquine; DC: dendritic cells; FOB: follicular B cells; GC: germinal center; Ig: immunoglobulin; LPS: lipopolysaccharide; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; MFI: mean fluorescence intensity; MZB: marginal zone B cells; NP-CGG: 4-hydroxy-3-nitrophenylacetyl-chicken gamma globulin; OCR: oxygen consumption rate; oxLDL: oxidized low-density lipoprotein; PC: plasma cells; Rapa: rapamycin; SQSTM1/p62: sequestosome 1; SRBC: sheep red blood cells; Tfh: follicular helper T cells; TLR: toll-like receptor. [ABSTRACT FROM AUTHOR]

Scavenger receptors play a critical role in innate immunity by acting as the pattern-recognition receptors. There are six class B scavenger receptors homologs in C. elegans. However, it remains unclear whether they are required for host defense against bacterial pathogens. Here, we show that, of the six SCAV proteins, only loss of function scav-5 protect C. elegans against pathogenic bacteria S. typhimurium SL1344 and P. aeruginosa PA14 by different mechanism. scav-5 mutants are resistant to S. typhimurium SL1344 due to dietary restriction. While scav-5 acts upstream of or in parallel to tir-1 in conserved PMK-1 p38 MAPK pathway to upregulate the innate immune response to defend worms against P. aeruginosa PA14. This is the first demonstration of a role for SCAV-5 in host defense against pathogenic bacteria. Our results provide an important basis for further elucidating the underlying molecular mechanism by which scav-5 regulates innate immune responses.

Scavenger receptors play a critical role in innate immunity by acting as the pattern-recognition receptors. There are six class B scavenger receptors homologs in C. elegans. However, it remains unclear whether they are required for host defense against bacterial pathogens. Here, we show that, of the six SCAV proteins, only loss of function scav-5 protect C. elegans against pathogenic bacteria S. typhimurium SL1344 and P. aeruginosa PA14 by different mechanism. scav-5 mutants are resistant to S. typhimurium SL1344 due to dietary restriction. While scav-5 acts upstream of or in parallel to tir-1 in conserved PMK-1 p38 MAPK pathway to upregulate the innate immune response to defend worms against P. aeruginosa PA14. This is the first demonstration of a role for SCAV-5 in host defense against pathogenic bacteria. Our results provide an important basis for further elucidating the underlying molecular mechanism by which scav-5 regulates innate immune responses. [ABSTRACT FROM AUTHOR]

Lipids released from circulating lipoproteins by intravascular action of lipoprotein lipase (LpL) reach parenchymal cells in tissues with a non-fenestrated endothelium by transfer through or around endothelial cells. The actions of LpL are controlled at multiple sites, its synthesis and release by myocytes and adipocytes, its transit and association with the endothelial cell luminal surface, and finally its activation and inhibition by a number of proteins and by its product non-esterified fatty acids. Multiple pathways mediate endothelial transit of lipids into muscle and adipose tissues. These include movement of fatty acids via the endothelial cell fatty acid transporter CD36 and movement of whole or partially LpL-hydrolyzed lipoproteins via other apical endothelial cell receptors such as SR-B1and Alk1. Lipids also likely change the barrier function of the endothelium and operation of the paracellular pathway around endothelial cells. This review summarizes in vitro and in vivo support for the key role of endothelial cells in delivery of lipids and highlights incompletely understood processes that are the focus of active investigation. [Display omitted] • Endothelial cell (EC) lipoprotein lipase (LpL) originates in adipocytes and myocytes. • Glycosylphosphatidylinositol-anchored HDL binding protein 1 (GPIHBP1) anchors and stabilizes LpL. • Fatty acids and angiopoietin-like proteins inhibit LpL. • Fatty acids from chylomicrons, very low density lipoproteins and adipose tissue have different routes for tissue uptake. • Transcytosis of lipids across ECs involves receptors – CD36, SR-B1, Alk1. [ABSTRACT FROM AUTHOR]

Abstract Background Oxidized low-density lipoproteins and scavenger receptors (SRs) play an important role in the formation and development of atherosclerotic plaques. However, little is known about their presence in epicardial adipose tissue (EAT). The objective of the study was to evaluate the mRNA expression of different SRs in EAT of patients with ischemic heart disease (IHD), stratifying by diabetes status and its association with clinical and biochemical variables. Methods We analyzed the mRNA expression of SRs (LOX-1, MSR1, CXCL16, CD36 and CL-P1) and macrophage markers (CD68, CD11c and CD206) in EAT from 45 patients with IHD (23 with type 2 diabetes mellitus (T2DM) and 22 without T2DM) and 23 controls without IHD or T2DM. Results LOX-1, CL-P1, CD68 and CD11c mRNA expression were significantly higher in diabetic patients with IHD when compared with those without T2DM and control patients. MSR1, CXCL16, CD36 and CD206 showed no significant differences. In IHD patients, LOX-1 (OR 2.9; 95% CI 1.6–6.7; P = 0.019) and CD68 mRNA expression (OR 1.7; 95% CI 0.98–4.5; P = 0.049) were identified as independent risk factors associated with T2DM. Glucose and glycated hemoglobin were also shown to be risk factors. Conclusions SRs mRNA expression is found in EAT. LOX-1 and CD68 and were higher in IHD patients with T2DM and were identified as a cardiovascular risk factor of T2DM. This study suggests the importance of EAT in coronary atherosclerosis among patients with T2DM.

Background and Objectives: Cardiovascular (CV) risk is elevated in rheumatoid arthritis (RA). RA patient plasma causes pro-atherogenic derangements in cholesterol transport leading to macrophage foam cell formation (FCF). The TARGET randomized clinical trial compares CV benefits of 2 RA drug regimens. Hydoxychloroquine (HCQ) is a key medication used in TARGET. This study examines effects of HCQ on lipid transport to elucidate mechanisms underlying TARGET outcomes and as an indicator of likely HCQ effects on atherosclerosis in RA. Materials and Methods: THP1 human macrophages were exposed to media alone, IFNγ (atherogenic cytokine), HCQ, or HCQ + IFNγ. Cholesterol efflux protein and scavenger receptor mRNA levels were quantified by qRT-PCR and corresponding protein levels were assessed by Western blot. FCF was evaluated via Oil-Red-O and fluorescent-oxidized LDL. Intracellular cholesterol and efflux were quantified with Amplex Red assay. Results: With the exception of a decrease in the efflux protein cholesterol 27-hydroxylase in the presence IFNγ at all HCQ concentrations, no significant effect on gene or protein expression was observed upon macrophage exposure to HCQ and this was reflected in the lack of change in FCF and oxidized LDL uptake. Conclusions: HCQ did not significantly affect THP1 macrophage cholesterol transport. This is consistent with TARGET, which postulates superior effects of anti-TNF agents over sulfasalazine + HCQ.