Targeted theranostic photoactivation on atherosclerosis

Background Photoactivation targeting macrophages has emerged as a therapeutic strategy for atherosclerosis, but limited targetable ability of photosensitizers to the lesions hinders its applications. Moreover, the molecular mechanistic insight to its phototherapeutic effects on atheroma is still lacking. Herein, we developed a macrophage targetable near-infrared fluorescence (NIRF) emitting phototheranostic agent by conjugating dextran sulfate (DS) to chlorin e6 (Ce6) and estimated its phototherapeutic feasibility in murine atheroma. Also, the phototherapeutic mechanisms of DS-Ce6 on atherosclerosis were investigated. Results The phototheranostic agent DS-Ce6 efficiently internalized into the activated macrophages and foam cells via scavenger receptor-A (SR-A) mediated endocytosis. Customized serial optical imaging-guided photoactivation of DS-Ce6 by light illumination reduced both atheroma burden and inflammation in murine models. Immuno-fluorescence and -histochemical analyses revealed that the photoactivation of DS-Ce6 produced a prominent increase in macrophage-associated apoptotic bodies 1 week after laser irradiation and induced autophagy with Mer tyrosine-protein kinase expression as early as day 1, indicative of an enhanced efferocytosis in atheroma. Conclusion Imaging-guided DS-Ce6 photoactivation was able to in vivo detect inflammatory activity in atheroma as well as to simultaneously reduce both plaque burden and inflammation by harmonic contribution of apoptosis, autophagy, and lesional efferocytosis. These results suggest that macrophage targetable phototheranostic nanoagents will be a promising theranostic strategy for high-risk atheroma. Graphical abstract

Class A Scavenger Receptor-Mediated Phagocytosis of Bovine Milk Exosomes in Murine Bone Marrow-Derived Macrophages

Objectives Bovine milk exosomes (BMEs) are promising candidates for delivering drugs to brain tumors because they are scalable, bioavailable after oral administration, and cross the blood-brain barrier. The use of BMEs in drug delivery is limited by their rapid elimination by macrophages. The objectives of this study were to identify the BME transporter and assess BME transport kinetics in murine bone marrow-derived macrophages (BMDMs) as a first step toward developing strategies that decrease the elimination of drug-loaded BMEs. Methods BMEs were isolated by differential centrifugation from skim milk. For transport studies, proteins and lipids on the BME surface were labeled with HiLyte™ Fluor 750 hydrazide and PKH26, respectively, and RNAs in BMEs were labeled with Exo-Red; unlabeled BMEs were used to assess background noise. Bone marrow cells were isolated from the femur and tibia of both C57BL/6J and scavenger receptor A-I/II knockout mice and differentiated ex vivo into BMDMs for use in transport studies. ANOVA, Dunnett's and Kruskal-Wallis test, Dunn's post-hoc test, unpaired t-test, and two-tailed Mann–Whitney U tests were used for statistical analysis; P < 0.05 was considered statistically significant. Results The uptake of BME was not saturated at the highest concentration used (4.3 × 1011 BMEs/mL) and the longest incubation time (53 h) tested. Chemical inhibition of phagocytosis by cytochalasin D led to a 69 ± 18% decrease in BME uptake compared to solvent controls (P ˂ 0.05), whereas inhibition of macropinocytosis, caveolar-dependent endocytosis, and endocytosis of clathrin-coated vesicles had no significant effect on BME uptake (11%-33% decrease compared to controls; P > 0.05). Treatment with inhibitors of class A scavenger receptor (CASR), fucoidan and dextran sulfate caused a 70 ± 8.1% and 70 ± 18% decrease (P ˂ 0.05), respectively, in BME uptake. The role of CASR in BME uptake was confirmed by using a genetics approach: the uptake of BMEs by BMDMs from scavenger receptor A-I/II knockout mice decreased by 58 ± 23% compared to BMDMs from wild-type mice (P ˂ 0.05). Conclusions BME uptake is facilitated by CASR in BMDMs and uptake cannot be saturated under physiological conditions. Funding Sources NIH 1P20GM104320, and NIFA 2016–67,001-25,301 and 2020–67,017-30,834, USDA Hatch-1,011,996, and USDA W4002 (all to J.Z.). J.Z is a consultant for PureTech Health, Inc.

New laboratory biomarkers of rheumatoid arthritis

The review presents data on new biomarkers for the diagnosis of rheumatoid arthritis, considers the diagnostic parameters of antibodies to carbamylated proteins, antibodies to peptidyl arginine deaminase, antibodies to homocysteinylated α1-antitrypsin, 14-3-3η, macrophage soluble scavenger receptor A. The use of new biomarkers can improve the diagnosis of RA in the early stages, as well as stratify patients based on the prognosis of the disease and provide a rational selection of therapy.

TAp73 represses NF-κB–mediated recruitment of tumor-associated macrophages in breast cancer

Infiltration of tumor-promoting immune cells is a strong driver of tumor progression. Especially the accumulation of macrophages in the tumor microenvironment is known to facilitate tumor growth and to correlate with poor prognosis in many tumor types. TAp73, a member of the p53/p63/p73 family, acts as a tumor suppressor and has been shown to suppress tumor angiogenesis. However, what role TAp73 has in regulating immune cell infiltration is unknown. Here, we report that low levels of TAp73 correlate with an increased NF-κB–regulated inflammatory signature in breast cancer. Furthermore, we show that loss of TAp73 results in NF-κB hyperactivation and secretion of Ccl2, a known NF-κB target and chemoattractant for monocytes and macrophages. Importantly, TAp73-deficient tumors display an increased accumulation of protumoral macrophages that express the mannose receptor (CD206) and scavenger receptor A (CD204) compared to controls. The relevance of TAp73 expression in human breast carcinoma was further accentuated by revealing that TAp73 expression correlates negatively with the accumulation of protumoral CD163+ macrophages in breast cancer patient samples. Taken together, our findings suggest that TAp73 regulates macrophage accumulation and phenotype in breast cancer through inhibition of the NF-κB pathway.