Scavenger Receptor Research Articles

Chitosan oligosaccharides: A potential therapeutic agent for inhibiting foam cell formation in atherosclerosis

Foam cell formation is a key hallmark in atherosclerosis and associated cardiovascular diseases (CVDs). The potential anti-atherosclerotic potential of chitosan oligosaccharides (COS) was investigated using oxLDL-treated RAW264.7 murine cells. COS treatment led to a significant inhibition of lipid accumulation, as demonstrated by Oil Red O staining, and reduced levels of total cholesterol, free cholesterol, cholesterol esters, and triglycerides in.oxLDL-treated RAW264.7 cells. COS blocked cholesterol influx through down-regulating class A1 scavenger receptors (SR-A1) and cluster of differentiation 36 (CD36) expression and stimulated cholesterol efflux through up-regulating ABC transporters ABCA-1 and ABCG-1 expressions. Additionally, COS treatment stimulated nuclear signaling pathways involving peroxisome proliferator-activated receptor-γ (PPAR-γ) and liver X receptor α (LXR-α), and also led to the phosphorylation of AMP-activated protein kinase (AMPK). COS further demonstrated anti-inflammatory effects by inhibiting the production of pro-inflammatory cytokines and the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in oxLDL-treated RAW264.7 cells, through suppression of NF-κB signaling. Furthermore, COS alleviated oxidative stress induced by oxLDL by activating Nrf2 signaling and enhancing the expression of antioxidant genes, including heme oxygenase-1 (HO-1), superoxide dismutase (SOD), glutathione peroxidase (Gpx), and catalase (CAT). In conclusion, COS can be beneficial in preventing atherosclerosis and related diseases.

Rab5 regulates the antimicrobial phagocytosis of hemocytes through class B scavenger receptor in Procambarus clarkii

Rab5 regulates the antimicrobial phagocytosis of hemocytes through class B scavenger receptor in Procambarus clarkii

SPA Promotes Atherosclerosis Through Mediating Macrophage Foam Cell Formation-Brief Report.

Atherosclerosis is a progressive inflammatory disease in which macrophage foam cells play a central role in disease pathogenesis. SPA (surfactant protein A) is a lipid-associating protein involved with regulating macrophage function in various inflammatory diseases. However, the role of SPA in atherosclerosis and macrophage foam cell formation has not been investigated. SPA expression was assessed in healthy and atherosclerotic human coronary arteries and the brachiocephalic arteries of wild-type or ApoE-deficient mice fed high-fat diets for 4 weeks. Hypercholesteremic wild-type and SPA-deficient mice fed a high-fat diet for 6 weeks were investigated for atherosclerotic lesions in vivo. In vitro experiments using RAW264.7 macrophages, primary resident peritoneal macrophages extracted from wild-type or SPA-deficient mice, and human monocyte-derived macrophages from the peripheral blood of healthy donors determined the functional effects of SPA in macrophage foam cell formation. SPA expression was increased in atherosclerotic lesions in humans and ApoE-deficient mice and in response to a proatherosclerotic stimulus in vitro. SPA deficiency reduced the lipid profiles induced by hypercholesterolemia, attenuated atherosclerosis, and reduced the number of lesion-associated macrophage foam cells. In vitro studies revealed that SPA deficiency reduced intracellular cholesterol accumulation and macrophage foam cell formation. Mechanistically, SPA deficiency dramatically downregulated the expression of scavenger receptor CD36 (cluster of differentiation antigen 36) cellular and lesional expression. Importantly, SPA also increased CD36 expression in human monocyte-derived macrophages. Our results elucidate that SPA is a novel factor promoting atherosclerosis development. SPA enhances macrophage foam cell formation and atherosclerosis by increasing scavenger receptor CD36 expression, leading to increasing cellular OxLDL influx.

Cryo-EM reveals structural basis for human AIM/CD5L recognition of polymeric immunoglobulin M

Cell surface scavenger receptors contribute to homoeostasis and the response to pathogens and products associated with damage by binding to common molecular features on a wide range of targets. Apoptosis inhibitor of macrophage (AIM/CD5L) is a soluble protein belonging to the scavenger receptor cysteine-rich (SRCR) superfamily that contributes to prevention of a wide range of diseases associated with infection, inflammation, and cancer. AIM forms complexes with IgM pentamers which helps maintain high-levels of circulating AIM in serum for subsequent activation on release from the complex. The structural basis for AIM recognition of IgM as well as other binding targets is unknown. Here we apply cryogenic electron microscopy imaging (cryo-EM) to show how interfaces on both of AIM’s C-terminal SRCR domains interact with the Fcμ constant region and J chain components of the IgM core. Both SRCR interfaces are also shown to contribute interactions important for AIM binding to damage-associated molecular patterns (DAMPs).

Biomimetic porphyrin-lipid nanoparticles - novel nanoscale theranostics for multimodal imaging and therapy in atherosclerotic cardiovascular disease

Abstract Background High-density lipoprotein (HDL) mimetic nanoagents have unrealized potential for atherosclerosis theranostics. Porphyrin-lipid HDL mimetic nanoparticles (Por-HDL-NPs) incorporate a porphyrin-lipid conjugate which permits near infrared fluorescence imaging and positron emission tomography (PET) through chelation of Copper-64 (64Cu). The outer shell contains apolipoprotein A-I mimetic peptide R4F designed to interact with scavenger receptor class B type I (SR-BI), enabling macrophage-targeting and therapeutic effects. Purpose To investigate the multimodal imaging, macrophage-targeting and therapeutic properties of Por-HDL-NPs and applications in atherosclerotic cardiovascular disease. Methods In vitro, the cholesterol efflux capacity of PBS (control), reconstituted HDL (rHDL) and Por-HDL-NPs was determined in immortalized bone marrow-derived macrophages (iBMDMs) loaded with [³H]-cholesterol. Real-time quantitative PCR (RT-qPCR) assessed mRNA levels of inflammatory mediators. ELISAs and Western blotting measured changes in protein levels. Apolipoprotein (Apo)e-/- mice were fed high-cholesterol diet (HCD) for 6 weeks, for early-stage plaque, and 13 weeks for the unstable plaque model in which two partial stenoses were made in the right carotid artery. PET and fluorescence (IVIS, flow cytometry, microscopy) imaging identified Por-HDL-NPs in plaques, circulating and aortic cells. Histological techniques assessed plaque area and composition in aortic sinus and carotid artery sections. Results Por-HDL-NPs were internalized by iBMDMs, visualized via fluorescence microscopy and flow cytometry. Por-HDL-NPs increased cholesterol efflux (49%, P<0.05), compared to rHDL. Por-HDL-NPs reduced macrophage mRNA levels of Il-1b (88%), Il-18 (54%) and Ccl5 (75%), and protein secretion of IL-1β (69%) and CCL5 (82%), P<0.05. Por-HDL-NPs suppressed inflammasome components Nlrp3 (69%) and Asc (36%), and activation of inflammatory transcription factor p65-NF-κB (53%), P<0.05. SR-BI siRNA knockdown and methyl-β-cyclodextrin, revealed that the anti-inflammatory properties of Por-HDL-NPs were independent of SR-BI and cholesterol efflux. In Apoe-/- mice, PET imaging showed 64Cu-Por-HDL-NPs localized in hearts and could detect increases in plaque size over time with HCD feeding. Por-HDL-NP fluorescence was detected within aortic sinus and unstable carotid plaques, co-localized with CD68+ macrophages. Por-HDL-NP-treated mice had smaller early-stage (22%) and unstable plaques (52%) than control PBS-treated mice, P<0.05. Por-HDL-NP mice had fewer circulating (32%) and aortic monocytes (81%), and a reduction in aortic arch Rela (26%), P<0.05. Conclusions Por-HDL-NPs present as potential nanoscale theranostics for atherosclerotic cardiovascular disease. Por-HDL-NPs can detect plaques using multiple imaging modalities and exhibit atheroprotective effects.Atherosclerosis imaging with Por-HDL-NPs

Monocyte response to mitochondrial DAMPs in elderly subjects: a possible contribution to chronic inflammation and atherosclerosis

Abstract Background Aging is an important risk factor for atherosclerosis and persists as an independent contributor when all other known factors are controlled. Circulating free mitochondrial DNA (cf-mtDNA) can activate immune cells, including monocytes, that promote plaque formation and produce proinflammatory cytokines [1]. Several receptors, including TLR9, AIM2, NLRP3, cGAS can bind cf-mtDNA and activate downstream pathways, leading to the activation of proinflammatory genes [2]. We previously showed that mtDNA increases with age, and at the highest concentrations observed in plasma, can enhance the pro-inflammatory effect of bacterial PAMPs [3]. Nevertheless, it is unknown if the pathways triggered by mtDNA are functionally preserved in elderly, and if it can synergize with oxidized low-density lipoproteins (ox-LDL), which are known to interact with TLR4 and TLR2, in concert with scavenger receptors to regulate the inflammatory microenvironment in atherosclerosis. Purpose This study aims to understand if and how the cf-mtDNA activates monocytes triggering an inflammatory response, if monocyte from young and old donors present a different response to mtDNA if age-related difference in the functional activity of these cells. Methods We selected 10 old subjects (74.4 ± 2.4 y.o.; 2M:8F) without a history of cardiovascular or peripheral arterial diseases, 4 ultranonagenarians (98.3 ± 4.7 y.o.; 1M:3F) and 9 sex-matched young controls (28.4 ± 7.3 y.o.; 0M:9F). Monocytes were isolated from blood samples, and inflammatory response to mtDNA alone or in combination with LPS was assessed, by analyzing TLR9 expression, NF-kB activation and the release in the supernatants of a panel of proinflammatory cytokines. Results Monocyte expression of the mtDNA receptor TLR9 showed a slight reduction with aging, and is similar in old subjects and ultranonagenarians. mtDNA was internalized only in cells pre-treated with LPS and co-localized with TLR9. When internalization occurred, monocytes treated with mtDNA+LPS, released pro-inflammatory cytokines at higher levels than cells treated with LPS alone. Monocytes from elderly subjects showed a partial impairment in mtDNA uptake, and a lower capability to activate TLR9 downstream pathway. However, the capability to secrete pro-inflammatory cytokines (TNF-α, IL-1β, IL-6) was not compromised, and NF-kB translocation into the nucleus after treatment with mtDNA is preserved, suggesting that compensatory mechanisms allowed mtDNA-driven activation of monocytes in elderly people. Conclusions The capability of mtDNA to promote an inflammatory response is preserved in elderly people and is still present in ultranonagenarians subjects. As mtDNA plasma levels increase with aging, mtDNA likely act as proinflammatory agents in aged people and can contribute to maintain inflammation in the atherosclerotic plaques. Further studies will clarify if mtDNA can act synergistically with ox-LDL to promote monocyte activation.

Targeting CD5 chimeric antigen receptor-engineered natural killer cells against T-cell malignancies

BackgroundChimeric antigen receptor engineered T cells (CAR-T) have demonstrated promising clinical efficacy in B-cell malignancies, and the approach has been extended to T-cell malignancies. However, the use of allogeneic T cells in CAR therapy poses a challenge due to the risk of graft-versus-host disease. Recently, natural killer (NK) cells have exhibited “off‑the‑shelf” availability. The nanobody-based CAR structures have attracted much attention for their therapeutic potential owing to the advantages of nanobody, including small size, optimal stability, high affinity and manufacturing feasibility. CD5, a common surface marker of malignant T cells, has three scavenger receptor cysteine-rich domains (D1-D3) in the extracellular region. The present study aims to construct “off‑the‑shelf” CAR-NK cells targeting the membrane-proximal domain of CD5 derived from nanobody against T-cell malignancies.MethodsAnti-CD5-D3 nanobody was screened by phage display technology, followed by constructing fourth-generation CAR plasmids ectopically producing IL-15 to generate CD5 CAR-NK cells derived from peripheral blood. And the second-generation CD5 CAR-T cells based on nanobody were generated, referred to as 5D.b CAR-T and 12 C.b CAR-T. Furthermore, CAR-NK cells without IL-15 (IL-15△ CAR-NK) were generated to assess the impact on cytotoxicity of CAR-NK cells. Cytotoxic activity against CD5+ hematologic malignant cell lines and normal T cells was exerted in vitro and NOD/ShiLtJGpt-Prkdcem26Cd52Il2rgem26Cd22/Gpt mouse model transplanted with Jurkat-Luc cells was used to evaluate the antitumor efficacy of CD5 CAR-NK cells in vivo.ResultsTwo nanobodies (5D and 12 C) competed for binding to the epitope of CD5-D3. 12 C CAR-NK cells were superior to 5D CAR-NK cells in antitumor potential and 12 C.b CAR-T cells exhibited superior cytotoxic activity than 5D CAR-T cells ex vivo. So, 12 C was regarded as the optimal nanobody. 12 C CAR-NK cells and IL-15△ CAR-NK cells exhibited robust cytotoxicity against CD5+ malignant cell lines and controlled disease progression in xenograft mouse model. 12 C CAR-NK cells demonstrated greater antitumor activity compared to that of IL-15△ CAR-NK cells in vitro and in vivo.ConclusionsTaken together, the fourth-generation nanobody-derived anti-CD5 CAR-NK cells may be a promising therapeutic against T-cell malignancies.

TLR4 promotes smooth muscle cell-derived foam cells formation by inducing receptor-independent macropinocytosis.

Foam cells are primarily formed through scavenger receptors that mediate the uptake of various modified low-density lipoproteins (LDL) into cells. In addition to the receptor-dependent pathway, macropinocytosis is an essential non-receptor endocytic pathway for vascular smooth muscle cells (VSMCs) to take up lipids. However, the molecular mechanisms underlying this process remain unclear. Primary cultured VSMCs were stimulated with 200 ng/ml lipopolysaccharide (LPS) and 200 μg/ml native LDL (nLDL). We observed a significant increase in TLR4 protein expression and a significant activation of macropinocytosis, which correlated with the highest uptake of nLDL and intracellular lipid deposition in WT VSMCs. However, macropinocytosis was inhibited and lipid accumulation decreased after treatment with macropinocytosis inhibitors and Syk inhibitors in WT VSMCs. Consistently, TLR4 knockout significantly suppressed macropinocytosis and lipid droplets accumulation in VSMCs. Taken together, our findings suggest a critical role of TLR4/Syk signaling in promoting receptor-independent macropinocytosis leading to VSMC-derived foam cells formation.

CD36 deficiency protects lipopolysaccharide-induced sepsis via inhibiting CerS6-mediated endoplasmic reticulum stress

The type 2 scavenger receptor CD36 functions not only as a long chain fatty acid transporter, but also as a pro-inflammatory mediator. Ceramide is the simple N-acylated form of sphingosine and exerts distinct biological activity depending on its acyl chain length. Six ceramide synthases (CerS) in mammals determine the chain length of ceramide species, and CerS6 mainly produces C16-ceramide. Endotoxin-induced septic shock shows high mortality, but the pathophysiologic role of sphingolipids involved in this process has been hardly investigated. This paper aims to highlight the different role of CerS isoforms in endotoxin-induced inflammatory responses and the regulatory role of CD36 in CerS6 protein degradation with an emphasis as the potential therapeutic candidates in humans. Lipopolysaccharide (LPS), the endotoxin of the Gram-negative bacterial cell wall, was treated to induce endotoxin-induced inflammation both in vitro and in vivo. CerS6-derived C16-ceramide propagated LPS-induced inflammatory responses activating various intracellular signaling pathways, such as mitogen-activated protein kinase and nuclear factor-κB, resulting in the formation of inflammasome complex and pro-inflammatory cytokines. Mechanistically, CerS6-derived C16-ceramide augmented inflammatory responses via endoplasmic reticulum stress, and CerS6 protein stability was regulated by CD36. Finally, CerS6 protein expression and LPS-induced lethality were strikingly reduced in CD36 knockout mice. Collectively, our findings show that CerS6-derived C16-ceramide plays a pivotal role in endotoxin-induced inflammation and suggest CerS6 and its regulator CD36 as possible targets for therapy under life-threatening inflammation such as septic shock.

Characterization of cellular and molecular immune components of the painted white sea urchin Lytechinus pictus in response to bacterial infection.

Sea urchins are basal deuterostomes that share key molecular components of innate immunity with vertebrates. They are a powerful model for the study of innate immune system evolution and function, especially during early development. Here we characterize the morphology and associated molecular markers of larval immune cell types in a newly developed model sea urchin, Lytechinus pictus. We then challenge larvae through infection with an established pathogenic Vibrio and characterize phenotypic and molecular responses. We contrast these to the previously described immune responses of the purple sea urchin Strongylocentrotus purpuratus. The results revealed shared cellular morphologies and homologs of known pigment cell immunocyte markers (PKS, srcr142) but a striking absence of subsets of perforin-like macpf genes in blastocoelar cell immunocytes. We also identified novel patterning of cells expressing a scavenger receptor cysteine rich (SRCR) gene in the coelomic pouches of the larva (the embryonic stem cell niche). The SRCR signal becomes further enriched in both pouches in response to bacterial infection. Collectively, these results provide a foundation for the study of immune responses in L. pictus. The characterization of the larval immune system of this rapidly developing and genetically enabled sea urchin species will facilitate more sophisticated studies of innate immunity and the crosstalk between the immune system and development.

Elucidating macrophage scavenger receptor 1's mechanistic contribution as a shared molecular mediator in obesity and thyroid cancer pathogenesis via bioinformatics analysis.

Obesity is a disease characterized by the excessive accumulation of fat. Concurrently, thyroid carcinoma (THCA) stands as the foremost endocrine malignancy. Despite the observed escalation in concurrent prevalence of both conditions, the underlying interconnections remain elusive. This indicates the need to identify potential biomarkers to predict the pathways through which obesity and THCA coexist. The study employed a variety of methods, including differential gene expression analysis, Weighted Gene Co-expression Network Analysis (WGCNA), and gene enrichment analysis. It was also supplemented with immunohistochemical data from the Human Protein Atlas (HPA), advanced machine learning techniques, and related experiments such as qPCR, to identify important pathways and key genes shared between obesity and THCA. Through differential gene expression analysis, WGCNA, and machine learning methods, we identified three biomarkers (IL6R, GZMB, and MSR1) associated with obesity. After validation analysis using THCA-related datasets and biological experiments, we selected Macrophage Scavenger Receptor 1 (MSR1) as a key gene for THCA analysis. The final analysis revealed that MSR1 is closely related to the degree of immune cell infiltration in patients with obesity and THCA, suggesting that this gene may be a potential intervention target for both obesity and THCA. Our research indicates that MSR1 may influence the occurrence and development of obesity and THCA by regulating the infiltration level of immune cells. This lays the foundation for future research on targeted therapies based on their shared mechanisms.

Erratum: Letter to the Editor: Scavenger receptor a is a major homeostatic regulator that restrains drug-induced liver injury.

Erratum: Letter to the Editor: Scavenger receptor a is a major homeostatic regulator that restrains drug-induced liver injury.

Nanoparticle-Directed Antioxidant Therapy Can Ameliorate Disease Progression in a Novel, Diet-Inducible Model of Coronary Artery Disease.

Oxidative stress plays a crucial role in the pathogenesis of coronary artery disease. In cardiovascular research using murine models, the generation and maintenance of models with robust coronary arterial atherosclerosis has been challenging. We characterized a new mouse model in which the last 3 amino acids of the carboxyl terminus of the HDL (high-density lipoprotein) receptor (SR-B1 [scavenger receptor class B, member 1]) were deleted in a low-density lipoprotein receptor knockout (LDLR-/-) mouse model (SR-B1ΔCT/LDLR-/-) fed an atherogenic diet. We also tested the therapeutic effects of an oxidative stress-targeted nanoparticle in atherogenic diet-fed SR-B1ΔCT/LDLR-/- mice. The SR-B1ΔCT/LDLR-/- mice fed an atherogenic diet had occlusive coronary artery atherosclerosis, impaired cardiac function, and a dramatically lower survival rate, compared with LDLR-/- mice fed the same diet. As SR-B1ΔCT/LDLR-/- mice do not exhibit female infertility or low pup yield, they are far easier and less costly to use than the previously described SR-B1-based models of coronary artery disease. We found that treatment with the targeted nanoparticles improved the cardiac functions and corrected hematologic abnormalities caused by the atherogenic diet in SR-B1ΔCT/LDLR-/- mice but did not alter the distinctive plasma lipid levels. The SR-B1ΔCT/LDLR-/- mice developed diet-inducible, fatal atherosclerotic coronary artery disease, which could be ameliorated by targeted nanoparticle therapy. Our study provides new tools for the development of cardiovascular therapies.

Distinct roles of size-defined HDL subpopulations in cardiovascular disease.

Doubts about whether high-density lipoprotein-cholesterol (HDL-C) levels are causally related to atherosclerotic cardiovascular disease (CVD) risk have stimulated research on identifying HDL-related metrics that might better reflect its cardioprotective functions. HDL is made up of different types of particles that vary in size, protein and lipid composition, and function. This review focuses on recent findings on the specific roles of HDL subpopulations defined by size in CVD. Small HDL particles are more effective than larger particles at promoting cellular cholesterol efflux because apolipoprotein A-I on their surface better engages ABCA1 (ATP binding cassette subfamily A member 1). In contrast, large HDL particles bind more effectively to scavenger receptor class B type 1 on endothelial cells, which helps prevent LDL from moving into the artery wall. The specific role of medium-sized HDL particles, the most abundant subpopulation, is still unclear. HDL is made up of subpopulations of different sizes of particles, with selective functional roles for small and large HDLs. The function of HDL may depend more on the size and composition of its subpopulations than on HDL-C levels. Further research is required to understand how these different HDL subpopulations influence the development of CVD.

The GPI sidechain of Toxoplasma gondii inhibits parasite pathogenesis.

Glycosylphosphatidylinositols (GPIs) are highly conserved anchors for eukaryotic cell surface proteins. The apicomplexan parasite, Toxoplasma gondii, is a widespread intracellular parasite of warm-blooded animals whose plasma membrane is covered with GPI-anchored proteins, and free GPIs called GIPLs. While the glycan portion is conserved, species differ in sidechains added to the triple mannose core. The functional significance of the Glcα1,4GalNAcβ1- sidechain reported in Toxoplasma gondii has remained largely unknown without understanding its biosynthesis. Here we identify and disrupt two glycosyltransferase genes and confirm their respective roles by serology and mass spectrometry. Parasites lacking the sidechain on account of deletion of the first glycosyltransferase, PIGJ, exhibit increased virulence during primary and secondary infections, suggesting it is an important pathogenesis factor. Cytokine responses, antibody recognition of GPI-anchored SAGs, and complement binding to PIGJ mutants are intact. By contrast, the scavenger receptor CD36 shows enhanced binding to PIGJ mutants, potentially explaining a subtle tropism for macrophages detected early in infection. Galectin-3, which binds GIPLs, exhibits an enhancement of binding to PIGJ mutants, and the protection of galectin-3 knockout mice from lethality suggests that Δpigj parasite virulence in this context is sidechain dependent. Parasite numbers are not affected by Δpigj early in the infection in wild-type mice, suggesting a breakdown of tolerance. However, increased tissue cysts in the brains of mice infected with Δpigj parasites indicate an advantage over wild-type strains. Thus, the GPI sidechain of T. gondii plays a crucial and diverse role in regulating disease outcomes in the infected host.IMPORTANCEThe functional significance of sidechain modifications to the glycosylphosphatidylinositol (GPI) anchor in parasites has yet to be determined because the glycosyltransferases responsible for these modifications have not been identified. Here we present identification and characterization of both Toxoplasmsa gondii GPI sidechain-modifying glycosyltransferases. Removal of the glycosyltransferase that adds the first GalNAc to the sidechain results in parasites without a sidechain on the GPI, and increased host susceptibility to infection. Loss of the second glycosyltransferase results in a sidechain with GalNAc alone, and no glucose added, and has negligible effect on disease outcomes. This indicates GPI sidechains are fundamental to host-parasite interactions.

Programmable Circular Multivalent Nanobody‐Targeting Chimeras (mNbTACs) for Multireceptor‐Mediated Protein Degradation and Targeted Drug Delivery

Multispecific therapeutics hold significant promise in drug delivery, protein degradation, and cell recruitment to address clinical issues of tumor heterogeneity, resistance, and immune evasion. However, their modular engineering remains challenging. We developed a targeted degradation platform, termed multivalent nanobody‐targeting chimeras (mNbTACs), by encoding diverse nanobody codons on a circular template using DNA printing technology. The homo‐ or hetero‐ mNbTACs specifically recognized membrane targets in a multivalent manner and simultaneously recruited scavenger receptors to favor clathrin‐/caveolae‐dependent endocytosis and lysosomal degradation of multiple proteins with high efficiency and selectivity. We demonstrated that a bispecific doxorubicin‐loaded mNbTAC, named Doxo‐mvNbsPPH, passively accumulated at tumor sites, specifically interacted with PD‐L1 and HER2 targets, and was rapidly transported into lysosome, inducing potent immunogenic cell death and alleviating immune checkpoint evasion. The synergistic boosting of innate and adaptive immunity promoted the infiltration and proliferation of CD8+ T cells in tumor microenvironment (an 11‐fold increase) with high toxicity and low exhaustion, eventually enhancing antitumor efficacy. Our mNbTAC platform provides multispecific therapeutics with variable valences and programmed species, whereas it induces targeted protein degradation through multireceptor‐mediated endocytosis and lysosomal degradation without the need for lysosome‐targeting receptors, representing a general and modular tool to harness extracellular proteome for disease treatment.

Programmable Circular Multivalent Nanobody-Targeting Chimeras (mNbTACs) for Multireceptor-Mediated Protein Degradation and Targeted Drug Delivery.

Multispecific therapeutics hold significant promise in drug delivery, protein degradation, and cell recruitment to address clinical issues of tumor heterogeneity, resistance, and immune evasion. However, their modular engineering remains challenging. We developed a targeted degradation platform, termed multivalent nanobody-targeting chimeras (mNbTACs), by encoding diverse nanobody codons on a circular template using DNA printing technology. The homo- or hetero- mNbTACs specifically recognized membrane targets in a multivalent manner and simultaneously recruited scavenger receptors to favor clathrin-/caveolae-dependent endocytosis and lysosomal degradation of multiple proteins with high efficiency and selectivity. We demonstrated that a bispecific doxorubicin-loaded mNbTAC, namedDoxo-mvNbsPPH, passively accumulated at tumor sites, specifically interacted with PD-L1and HER2targets, and was rapidly transported into lysosome, inducing potent immunogenic cell death and alleviating immune checkpoint evasion. The synergistic boosting of innate and adaptive immunity promoted the infiltration and proliferation of CD8+T cells in tumor microenvironment (an 11-fold increase) with high toxicity and low exhaustion, eventually enhancing antitumor efficacy. Our mNbTAC platform provides multispecific therapeutics with variable valences and programmed species, whereas it induces targeted protein degradation through multireceptor-mediated endocytosis and lysosomal degradation without the need for lysosome-targeting receptors, representing a general and modular tool to harness extracellular proteome for disease treatment.

Mating behaviour and cholesterol nutritional strategies promoted ovarian development of female swimming crab (Portunus trituberculatus).

Female crabs enter a stage of rapid ovarian development after mating, and cholesterol is a substrate for steroid hormone synthesis. Therefore, in this experiment, an 8-week feeding trial was conducted to investigate the effects of mating treatments (mated crab and unmated crab) and three dietary cholesterol levels (0·09 %, 0·79 % and 1·40 %) on ovarian development, cholesterol metabolism and steroid hormones metabolism of adult female swimming crab (Portunus trituberculatus). The results indicated that crabs fed the diet with 0·79 % cholesterol significantly increased gonadosomatic index (GSI) and vitellogenin (VTG) content than other treatments in the same mating status. Moreover, mated crabs had markedly increased GSI and VTG content in the ovary and hepatopancreas than unmated crabs. The histological observation found that exogenous vitellogenic oocytes appeared in the mated crabs, while previtellogenic oocytes and endogenous vitellogenic oocytes were the primary oocytes in unmated crabs. The transmission electron microscopy analysis showed that when fed diet with 0·79 % cholesterol, the unmated crabs contained more rough endoplasmic reticulum and mated crabs had higher yolk content than other treatments. Furthermore, mating treatment and dietary 0·79 % cholesterol level both promoted cholesterol deposition by up-regulation of the mRNA and protein expression levels of class B scavenger receptors 1 (Srb1), while stimulating the secretion of steroid hormones by up-regulation of the mRNA and protein expression of steroidogenic acute regulatory protein (Star). Overall, the present results indicated that mating behaviour plays a leading role in promoting ovarian development, and dietary 0·79 % cholesterol level can further promote ovarian development after mating.

Propionate Decreases Microglial Activation but Impairs Phagocytic Capacity in Response to Aggregated Fibrillar Amyloid Beta Protein.

Microglia, the innate immune cell of the brain, are a principal player in Alzheimer's disease (AD) pathogenesis. Their surveillance of the brain leads to interaction with the protein aggregates that drive AD pathogenesis, most notably Amyloid Beta (Aβ). Microglia attempt to clear and degrade Aβ using phagocytic machinery, spurring damaging neuroinflammation in the process. Thus, modulation of the microglial response to Aβ is crucial in mitigating AD pathophysiology. SCFAs, microbial byproducts of dietary fiber fermentation, are blood-brain barrier permeable molecules that have recently been shown to modulate microglial function. It is unclear whether propionate, one representative SCFA, has beneficial or detrimental effects on microglia in AD. Thus, we investigated its impact on microglial Aβ response in vitro. Using a multiomics approach, we characterized the transcriptomic, metabolomic, and lipidomic responses of immortalized murine microglia following 1 h of Aβ stimulation, as well as characterizing Aβ phagocytosis and secretion of reactive nitrogen species. Propionate blunted the early inflammatory response driven by Aβ, downregulating the expression of many Aβ-stimulated immune genes, including those regulating inflammation, the immune complement system, and chemotaxis. Further, it reduced the expression of Apoe and inflammation-promoting Aβ-binding scavenger receptors such as Cd36 and Msr1 in favor of inflammation-dampening Lpl, although this led to impaired phagocytosis. Finally, propionate shifted microglial metabolism, altering phospholipid composition and diverting arginine metabolism, resulting in decreased nitric oxide production. Altogether, our data demonstrate a modulatory role of propionate on microglia that may dampen immune activation in response to Aβ, although at the expense of phagocytic capacity.

Blue Mussel-Derived Bioactive Peptides PIISVYWK (P1) and FSVVPSPK (P2): Promising Agents for Inhibiting Foam Cell Formation and Inflammation in Cardiovascular Diseases.

Atherosclerosis is a key etiological event in the development of cardiovascular diseases (CVDs), strongly linked to the formation of foam cells. This study explored the effects of two blue mussel-derived bioactive peptides (BAPs), PIISVYWK (P1) and FSVVPSPK (P2), on inhibiting foam cell formation and mitigating inflammation in oxLDL-treated RAW264.7 macrophages. Both peptides significantly suppressed intracellular lipid accumulation and cholesterol levels while promoting cholesterol efflux by downregulating cluster of differentiation 36 (CD36) and class A1 scavenger receptors (SR-A1) and upregulating ATP binding cassette subfamily A member 1 (ABCA-1) and ATP binding cassette subfamily G member 1 (ABCG-1) expressions. The increased expression of peroxisome proliferator-activated receptor-gamma (PPAR-γ) and liver X receptor-alpha (LXR-α) further validated their role in enhancing cholesterol efflux. Additionally, P1 and P2 inhibited foam cell formation in oxLDL-treated human aortic smooth muscle cells and exerted anti-inflammatory effects by reducing pro-inflammatory cytokines, nitric oxide (NO), prostaglandin E2 (PGE2), inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2), primarily through inhibiting NF-κB activation. Furthermore, P1 and P2 alleviated oxidative stress by activating the Nrf2/HO-1 pathway. Our findings demonstrate that P1 and P2 have significant potential in reducing foam cell formation and inflammation, both critical factors in atherosclerosis development. These peptides may serve as promising therapeutic agents for the prevention and treatment of CVDs associated with oxidative stress and inflammation.