Search Results (8)

Background/Objectives: Non-resolving inflammation in macrophage-like cells (MLCs) transdifferentiated from vascular smooth muscle cells and monocyte-derived macrophages aggravates atherosclerosis. We previously showed that polyphenolic protocatechuic acid (PCA) could reduce inflammation burden in monocyte-derived macrophages; however, it remains unknown how this compound affects MLCs inflammation. Methods: MLCs from the transdifferentiation of vascular smooth muscle cells induced by cholesterol and 30-week-old male ApoE^−/− mice fed a semi-purified AIN-93G diet containing either 0.003% (wt:wt) of PCA for a duration of 20 weeks were used to examine the impact of PCA on the inflammatory response of MLCs. Results: Physiologically achievable doses of PCA (0.25–1 μM) dose-dependently inhibited lipopolysaccharide-induced NF-κB activation and simultaneously reduced pro-inflammatory cytokine levels. Mechanistically, this effect was mediated by effecting exportin-1 function, promoting nuclear export of phosphorylated-p65, independent of NF-κB kinase inhibitor α/β/γ, NF-κB inhibitor α, or importin-mediated nuclear import of p-p65. PCA reduced the nucleocytoplasmic ratio of exportin-1 (44%) without altering its abundance. Importantly, dietary supplementation with PCA reduced interleukin-1β content within MLCs in atherosclerotic plaques of ApoE^−/− mice. In addition, dietary PCA reduced MLCs content in atherosclerotic plaques. Conclusions: PCA could attenuate inflammatory response in MLCs by targeting exportin-1 and also could inhibit the transdifferentiation of vascular smooth muscle cells into MLCs within atherosclerotic plaques, which might promote the translation from preclinical studies to clinical trials in patients with atherosclerosis. Full article

The intramuscular administration of polymerized type I collagen (PTIC) for adult symptomatic COVID-19 outpatients downregulated hyperinflammation and improved symptoms. We inferred that LAIR1 is a potential receptor for PTIC. Thus, a binding assay and surface plasmon resonance binding assay were performed to estimate the affinity of the interaction between LAIR1 and PTIC. M1 macrophages derived from THP-1 cells were cultured with 2–10% PTIC for 24 h. Lysates from PTIC-treated THP-1 cells, macrophage-like cells (MLCs), M1, M1 + IFN-γ, and M1 + LPS were analyzed by Western blot for NF-κB (p65), p38, STAT1, and pSTAT1 (tyrosine⁷⁰¹). Serum cytokine levels and monocyte LAIR1 expressions (Mo1 and Mo2) were analyzed by luminometry and flow cytometry in symptomatic COVID-19 outpatients on PTIC treatment. PTIC-bound LAIR1 had a similar affinity to collagen in M1 macrophages. It downregulated pSTAT1 in IFN-γ-induced M1. COVID-19 patients under PTIC treatment showed a significant decrease in Mo1 percentages and cytokines (IP-10/MIF/eotaxin/IL-8/IL-1RA/M-CSF) associated with STAT1 and an increase in the Mo2 subset. The inflammatory mediators and Mo1 downregulation were related to better oxygen saturation and decreased dyspnea, chest pain, cough, and chronic fatigue syndrome in the acute and long-term phase of infection. PTIC is an agonist of LAIR1 and downregulates STAT-1 phosphorylation. PTIC could be relevant for treating STAT1-mediated inflammatory diseases, including COVID-19 and long COVID. Full article

Atherosclerosis is caused by cholesterol accumulation within arteries. The intima is where atherosclerotic plaque accumulates and where lipid-laden foam cells reside. Intimal foam cells comprise of both monocyte-derived macrophages and macrophage-like cells (MLC) of vascular smooth muscle cell (VSMC) origin. Foam cells can remove cholesterol via apoAI-mediated cholesterol efflux and this process is regulated by the transporter ABCA1. The microRNA miR-33a-5p is thought to be atherogenic via silencing ABCA1 which promotes cholesterol retention and data has shown inhibiting miR-33a-5p in macrophages may be atheroprotective via enhancing apoAI-mediated cholesterol efflux. However, it is not entirely elucidated whether precisely inhibiting miR-33a-5p in MLC also increases ABCA1-dependent cholesterol efflux. Therefore, the purpose of this work is to test the hypothesis that inhibition of miR-33a-5p in cultured MLC enhances apoAI-mediated cholesterol efflux. In our study, we utilized the VSMC line MOVAS cells in our experiments, and cholesterol-loaded MOVAS cells to convert this cell line into MLC. Inhibition of miR-33a-5p was accomplished by transducing cells with a lentivirus that expresses an antagomiR directed at miR-33a-5p. Expression of miR-33a-5p was analyzed by qRT-PCR, ABCA1 protein expression was assessed via immunoblotting, and apoAI-mediated cholesterol efflux was measured using cholesterol efflux assays. In our results, we demonstrated that lentiviral vector-mediated knockdown of miR-33a-5p resulted in decreasing expression of this microRNA in cultured MLC. Moreover, reduction of miR-33a-5p in cultured MLC resulted in de-repression of ABCA1 expression, which caused ABCA1 protein upregulation in cultured MLC. Additionally, this increase in ABCA1 protein expression resulted in enhancing ABCA1-dependent cholesterol efflux through increasing apoAI-mediated cholesterol efflux in cultured MLC. From these findings, we conclude that inhibiting miR-33a-5p in MLC may protect against atherosclerosis by promoting ABCA1-dependent cholesterol efflux. Full article

Cholesterol-laden macrophages are recognized as a major contributor to atherosclerosis. However, recent evidence indicates that vascular smooth muscle cells (VSMC) that accumulate cholesterol and transdifferentiate into a macrophage-like cell (MLC) phenotype also play a role in atherosclerosis. Therefore, removing cholesterol from MLC may be a potential atheroprotective strategy. The two transporters which remove cholesterol from cells are ABCA1 and ABCG1, as they efflux cholesterol to apoAI and HDL, respectively. In this study, the well-characterized immortalized VSMC line MOVAS cells were edited to generate ABCA1- and ABCG1-knockout (KO) MOVAS cell lines. We cholesterol-loaded ABCA1-KO MOVAS cells, ABCG1-KO MOVAS cells, and wild-type MOVAS cells to convert cells into a MLC phenotype. When we measured apoAI- and HDL-mediated cholesterol efflux in these cells, we observed a drastic decrease in apoAI-mediated cholesterol efflux within ABCA1-KO MOVAS MLC, but HDL-mediated cholesterol efflux was only partially reduced in ABCG1-KO MOVAS cells. Since SR-BI also participates in HDL-mediated cholesterol efflux, we assessed SR-BI protein expression in ABCG1-KO MOVAS MLC and observed SR-BI upregulation, which offered a possible mechanism explaining why HDL-mediated cholesterol efflux remains maintained in ABCG1-KO MOVAS MLC. When we used lentivirus for shRNA-mediated knockdown of SR-BI in ABCG1-KO MOVAS MLC, this decreased HDL-mediated cholesterol efflux when compared to ABCG1-KO MOVAS MLC with unmanipulated SR-BI expression. Taken together, these major findings suggest that SR-BI expression in MLC of a VSMC origin plays a compensatory role in HDL-mediated cholesterol efflux when ABCG1 expression becomes impaired and provides insight on SR-BI demonstrating anti-atherogenic properties within VSMC/MLC. Full article

Macrophage-like cells (MLCs) are an emerging retinal biomarker. MLCs are increased in retinal vein occlusion (RVO) eyes, but their predictive value is unknown. This study investigated if MLCs can predict meaningful clinical outcomes. This prospective, cross-sectional study involved 46 eyes from 23 patients with unilateral RVO. Patients’ unaffected eyes were used as matched controls. MLCs were quantified to determine MLC density and percent image area. We collected demographic, clinical, ocular, and imaging characteristics at the time of MLC imaging. We additionally recorded best corrected visual acuity (BCVA) and number of intravitreal injections at 6 months and 12 months post-imaging. MLC density and percent area increased by 1.86 (p = 0.0266)- and 1.94 (p = 0.0415)-fold in RVO compared to control eyes. We found no significant correlation between MLC parameters and any baseline characteristic. MLC density was positively correlated with the number of intravitreal injections at 6 months (n = 12, r = 0.62, p = 0.03) and 12 months (n = 9, r = 0.80, p = 0.009) post-imaging. MLC percent area was correlated with LogMAR BCVA change over 12 months (n = 17, r = 0.57, p = 0.02). High MLC counts correlated with more future intravitreal injections and worse visual acuity outcomes, suggesting that MLCs are a biomarker for treatment resistant RVO eyes. Full article

Aim: To study the macrophage-like cells (MLC) of the inner retinal surface in eyes with retinal vein occlusions (RVO) and the association of MLC with clinical characteristics of RVO. Methods: In this retrospective cross-sectional study, the medical records and multimodal imaging data of treatment-naïve patients with unilateral RVO and no abnormalities of vitreoretinal interface electronic were reviewed and analyzed. To visualize MLC, structural projections of optical coherence tomography (OCT) angiography scans within a slab between two inner limiting membrane segmentation lines (with 0 and −9 µm offset) were evaluated. The density of MLC was calculated and compared between affected and fellow eyes of each patient with regards to OCT and clinical characteristics of RVO. Results: Thirty-six eyes (twenty-eight branch RVO and eight central RVO) of 36 patients (21 males and 15 females, mean age 48.9 ± 9.8 years) were included. The density of MLC in affected eye was statistically significantly higher than that of the fellow eye, 8.5 ± 5.5 and 4.0 ± 3.6 cells/mm², respectively (p < 0.001). The MLC density in the affected eye had a statistically significantly correlation with that of the fellow eye (r = 0.76, p = 0.0001), but with none of the OCT and clinical characteristics of the affected eye apart from the presence of subfoveal fluid. Eyes with subfoveal fluid had a statistically significantly higher mean number of MLC than that of eyes without subfoveal fluid, 12.6 ± 6.3 and 6.9 ± 4.0 cells/mm²_, respectively (p = 0.009). Conclusion: The number of MLC on the inner retinal surface increases in RVO eyes which may reflect the activation of inflammatory pathways. Full article

Macrophage-like cells (MLCs) are potential inflammatory biomarkers. We previously showed that MLCs are increased in proliferative diabetic retinopathy (PDR) eyes. Vision-threatening diabetic retinopathy (VTDR) includes PDR, severe non-PDR (NPDR), and diabetic macular edema (DME). No prior data exist on MLCs in eyes with severe NPDR or DME. This prospective, cross-sectional optical coherence tomography-angiography (OCT-A) imaging study included 40 eyes of 37 participants who had NPDR classified as non-VTDR (n = 18) or VTDR (n = 22). Repeated OCT-A images were registered, averaged, and used to quantify the main outcome measures: MLC density and percent area. MLC density and percent area were correlated with clinical characteristics, NPDR stage, presence of DME, and OCT central subfield thickness (CST). In VTDR eyes, MLC density (2.6-fold, p < 0.001) and MLC percent area (2.5-fold, p < 0.01) were increased compared with non-VTDR eyes. Multiple linear regression analysis between MLC metrics and clinical characteristics found that MLC density was positively correlated with worse NPDR severity (p = 0.023) and higher CST values (p = 0.010), while MLC percent area was only positively associated with increased CST values (p = 0.006). MLCs are increased in patients with VTDR. Macular edema is the most strongly associated factor with increased MLC numbers in NPDR eyes. Full article

Objectives: to quantitatively analyze macrophage-like cells (MLCs) at the vitreoretinal interface in retinal vein occlusion (RVO) using swept-source optical coherence tomography angiography (SS-OCTA) and en face optical coherence tomography (OCT). Methods: The study included 72 RVO patients, with 43 acute patients and 29 chronic patients. For a normal control, 64 fellow eyes were included. MLCs were visualized in a 5 μm en face OCT slab above the vitreoretinal interface centered on the fovea. After semi-automatic binarization and quantification, we evaluated the MLC count and density among groups. We also investigated the MLC density and distribution relative to retinal edema. Results: Morphological changes and congregation of MLCs appeared in RVO eyes. The MLC density of both the acute and chronic groups was significantly higher than that of the control eyes (p < 0.001). In the acute group, the MLC density of the edematous region was lower than both the non-edematous region (p < 0.001) and the whole image (p < 0.01). The MLC density in acute eyes was negatively correlated to central fovea thickness (CFT) (r = −0.352, p < 0.05). The MLC density in chronic eyes was positively correlated to CFT and mean retina thickness (MRT) (r = 0.406, p < 0.05; r = 0.412, p < 0.05, respectively). Conclusions: SS-OCTA is a viable and simple method for the characterization of MLCs at the vitreoretinal interface. A significant increase in the MLC density in both acute and chronic eyes implicates the activation and recruitment of MLCs in RVO and that the MLC density and distribution can be affected by retinal edema. Full article