No abstract

Background: Curcumin, the active ingredient in curcuma rhizomes, has a wide range of therapeutic effects. However, its atheroprotective activity in human acute monocytic leukemia THP-1 cells remains unclear. We investigated the activity and molecular mechanism of action of curcumin in polarized macrophages. Methods: Phorbol myristate acetate (PMA)-treated THP-1 cells were differentiated to macrophages, which were further polarized to M1 cells by lipopolysaccharide (LPS; 1 µg/ml) and interferon (IFN)-γ (20 ng/ml) and treated with varying curcumin concentrations. [³H]thymidine (³H-TdR) incorporation assays were utilized to measure curcumin-induced growth inhibition. The expression of tumor necrosis factor-a (TNF-a), interleukin (IL-6), and IL-12B (p40) were measured by quantitative real-time polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA). Macrophage polarization and its mechanism were evaluated by flow cytometry and western blot. Additionally, toll-like receptor 4 (TLR4) small interfering RNA and mitogen-activated protein kinase (MAPK) inhibitors were used to further confirm the molecular mechanism of curcumin on macrophage polarization. Results: Curcumin dose-dependently inhibited M1 macrophage polarization and the production of TNF-a, IL-6, and IL-12B (p40). It also decreased TLR4 expression, which regulates M1 macrophage polarization. Furthermore, curcumin significantly inhibited the phosphorylation of ERK, JNK, p38, and nuclear factor (NF)-γB. In contrast, SiTLR4 in combination with p-JNK, p-ERK, and p-p38 inhibition reduced the effect of curcumin on polarization. Conclusions: Curcumin can modulate macrophage polarization through TLR4-mediated signaling pathway inhibition, indicating that its effect on macrophage polarization is related to its anti-inflammatory and atheroprotective effects. Our data suggest that curcumin could be used as a therapeutic agent in atherosclerosis.

Background: Since December 2019, an outbreak of Coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2) initially emerged in Wuhan, China, and has spread worldwide now. Clinical features of patients with COVID-19 have been described. However, risk factors leading to in-hospital deterioration and poor prognosis in COVID-19 patients with severe disease have not been well identified. Methods: In this retrospective, single-center cohort study, 1190 adult inpatients (≥ 18 years old) with laboratoryconfirmed COVID-19 and determined outcomes (discharged or died) were included from Wuhan Infectious Disease Hospital from December 29, 2019 to February 28, 2020. The final follow-up date was March 2, 2020. Clinical data including characteristics, laboratory and imaging information as well as treatments were extracted from electronic medical records and compared. A multivariable logistic regression model was used to explore the potential predictors associated with in-hospital deterioration and death. Results: 1190 patients with confirmed COVID-19 were included. Their median age was 57 years (interquartile range 47-67 years). Two hundred and sixty-one patients (22%) developed a severe illness after admission. Multivariable logistic regression demonstrated that higher SOFA score (OR 1.32, 95% CI 1.22-1.43, per score increase, p < 0.001 for deterioration and OR 1.30, 95% CI 1.11-1.53, per score increase, p = 0.001 for death), lymphocytopenia (OR 1.81, 95% CI 1.13-2.89 p = 0.013 for deterioration; OR 4.44, 95% CI 1.26-15.87, p = 0.021 for death) on admission were independent risk factors for in-hospital deterioration from not severe to severe disease and for death in severe patients. On admission D-dimer greater than 1 μg/L (OR 3.28, 95% CI 1.19-9.04, p = 0.021), leukocytopenia (OR 5.10, 95% CI 1.25-20.78), thrombocytopenia (OR 8.37, 95% CI 2.04-34.44) and history of diabetes (OR 11.16, 95% CI 1.87-66.57, p = 0.008) were also associated with higher risks of in-hospital death in severe COVID-19 patients. Shorter time interval from illness onset to non-invasive mechanical ventilation in the survivors with severe disease was observed compared with non-survivors (10.5 days, IQR 9.25-11.0 vs. 16.0 days, IQR 11.0-19.0 days, p = 0.030). Treatment with glucocorticoids increased the risk of progression from not severe to severe disease (OR 3.79, 95% CI 2.39-6.01, p < 0.001). Administration of antiviral drugs especially oseltamivir or ganciclovir is associated with a decreased risk of death in severe patients (OR 0.17, 95% CI 0.05-0.64, p < 0.001).

Acclimation to irradiance was measured in terms of light-saturated photosynthetic carbon assimilation rates (P max ), Rubisco, and pigment content in mature field-grown rice (Oryza sativa) plants in tropical conditions. Measurements were made at different positions within the canopy alongside irradiance and daylight spectra. These data were compared with a second experiment in which acclimation to irradiance was assessed in uppermost leaves within whole-plant shading regimes (10% low light [LL], 40% medium light [ML], and 100% high light [HL] of full natural sunlight). Two varieties, japonica (tropical; new plant type [NPT]) and indica (IR72) were compared. Values for Rubisco amount, chlorophyll a/b, and P max all declined from the top to the base of the canopy. In the artificial shading experiment, acclimation of P max (measured at 350 L L Ϫ1 CO 2 ) occurred between LL and ML for IR72 with no difference observed between ML and HL. The Rubisco amount increased between ML and HL in IR72. A different pattern was seen for NPT with higher P max (measured at 350 L L Ϫ1 CO 2 ) at LL than IR72 and some acclimation of this parameter between ML and HL. Rubisco levels were higher in NPT than IR72 contrasting with P max . Comparison of data from both experiments suggests a leaf aging effect between the uppermost two leaf positions, which was not a result of irradiance acclimation. Results are discussed in terms of: (a) acclimation of photosynthesis and radiation use efficiency at high irradiance in rice, and (b) factors controlling photosynthetic rates of leaves within the canopy.A plant's light environment will commonly exhibit large changes in both intensity and spectral quality. In response, there are alterations in the composition of chloroplasts that adjust photosynthesis to the prevailing conditions. This is termed photosynthetic acclimation (Anderson et al., 1995) and results in optimization of light utilization and protects against the potential stress from excess light (Anderson and Osmond, 1987). Differences in anatomy can also be observed between high light-and low light-grown leaves (Weston et al., 2000). A correlation has been shown between the capacity of a plant species for acclimation and the range of habitats in which it is found (Murchie and Horton, 1997), and species inhabiting extreme environments may express particular aspects of acclimation to an exaggerated extent (Maxwell et al., 1999).On a chloroplast level, most plant species acclimate to irradiance over the long term by altering relative amounts of photosynthetic enzymes and pigmentprotein complexes. Growth or long-term presence in high irradiance results in a progressive loss of lightharvesting pigment proteins and a synthesis of electron transport and carbon assimilation components, compared with leaves exposed to low light (Anderson and Osmond, 1987; Anderson et al., 1995). As a result, the photosynthetic capacity (P max ) of high light-acclimated leaves is often consistently higher than low light leaves. Acclimation maintains ambient photo...