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To investigate the damage of rat alveolar type II epithelial cells(RLE-6 TN) caused by air fine particulate matter(PM_(2.5)) and its related mechanism.PM_(2.5) in the atmosphere of Weifang City in 2020 was collected and cell culture medium was used to prepare particulate suspension. RLE-6 TN cells were exposed to different concentrations(25, 50, 100, 200, 400 μg/mL) of particulate matter suspensions for 24 h. The morphological changes of RLE-6 TN cells were observed under inverted microscope, and the cell viability was determined by MTT method. The concentration of lactate dehydrogenase(LDH) in cell supernatant was determined by microplate method. DCFH-DA, Annexin V-FITC/PI, JC-1 probe and laser confocal fluorescence intensity were used to determine the levels of reactive oxygen species(ROS), apoptosis and mitochondrial membrane potential. Total superoxide dismutase(T-SOD), glutathione(GSH) and malondialdehyde(MDA) contents and activity levels in cells were determined by colorimetric method. Caspase-3 and Caspase-9 kit were used to detect the relative expression activity of apoptosis proteins.PM_(2.5) could lead to morphological changes of RLE-6 TN cells, enlarged cell space and decreased cell viability. Compared with the control group, there were statistically significant differences in each dose group(Plt;0.05). LDH concentration in the supernatant of ≥50 μg/mL infected group increased, and LDH concentration was ≥(377.82±29.84), which was significantly different from that of the control group(278.51±23.76)(Plt;0.05). The result of laser confocal detection of ROS showed that the intracellular green fluorescence increased gradually in the ≥50 μg/mL group, and the relative fluorescence intensity was ≥(2.77±0.18), which was statistically significant compared with the control group(Plt;0.05). The level of apoptosis was significantly increased compared with the control group(Plt;0.05). The level of mitochondrial membrane potential decreased gradually, and the level of mitochondrial membrane potential in the ≥25 μg/mL group was ≤(4.22±0.45), which was statistically different from that in the control group(6.16±0.49)(Plt;0.05). PM_(2.5) could reduce the levels of T-SOD and GSH, and the levels of T-SOD and GSH in ≥50 μg/mL exposed group were ≤(14.67±0.49) and ≤(433.29±39.24), respectively, significantly lower than those in control group((16.58±0.60) and(542.90±45.06))(Plt;0.05). MDA level increased with the increase of PM_(2.5) concentration. Compared with the control group(1.15±0.19), MDA level in ≥50 μg/mL exposed group was ≥(1.72±0.13), with statistical significance(Plt;0.05). The activity levels of Caspase-3 and Caspase-9 increased in ≥100 μg/mL group, and the activity levels were ≥(1.62±0.27) and ≥(1.23±0.06), respectively, compared with the control group, the differences were statistically significant(Plt;0.05).Exposure to a certain concentration of PM_(2.5) can induce oxidative stress of rat alveolar type II epithelial cells, reduce the membrane potential, and eventually lead to cell apoptosis.

Summary Bacterial vectors can be engineered to generate microscopic living therapeutics to produce and deliver anticancer agents. Escherichia coli Nissle 1917 (Nissle 1917) is a promising candidate with probiotic properties. Here, we used Nissle 1917 to develop a metabolic strategy to produce 5‐aminolevulinic acid (5‐ALA) from glucose as 5‐ALA plays an important role in the photodynamic therapy of cancers. The coexpression of hemAM and hemL using a low copy‐number plasmid led to remarkable accumulation of 5‐ALA. The downstream pathway of 5‐ALA biosynthesis was inhibited by levulinic acid (LA). Small‐scale cultures of engineered Nissle 1917 produced 300 mg l−1 of 5‐ALA. Recombinant Nissle 1917 was applied to deliver 5‐ALA to colorectal cancer cells, in which it induced the accumulation of antineoplastic protoporphyrin X (PpIX) and specific cytotoxicity towards colorectal cancer cells irradiated with a 630 nm laser. Moreover, this novel combination therapy proved effective in a mouse xenograft model and was not cytotoxic to normal tissues. These findings suggest that Nissle 1917 will serve as a potential carrier to effectively deliver 5‐ALA for cancer therapy.

To investigate the renal injury induced by cadmium chloride(CdCl_2) and the protective effect of vitamin C(VC) in mice.Forty healthy clean grade male Kunming mice were randomly divided into 4 groups: control group(double distilled water gavage and intraperitoneal injection), VC group(200 mg/kg VC gavage and double distilled water intraperitoneal injection), CdCl_2 group(double distilled water gavage and 2 mg/kg CdCl_2 intraperitoneal injection), VC+CdCl_(2 )group(200 mg/kg VC gavage and 2 mg/kg CdCl_2 intraperitoneal injection). Exposure for 30 days.24 hours after the last exposure, the eyeballs were taken out for blood, and the renal tissue was immediately taken out to calculate kidney coefficient and then separate renal cells. The levels of reactive oxygen species(ROS) were detected by DCFH-DA kit and flow cytometry. Blood urea nitrogen(BUN), serum creatinine(Scr)and β2 microglobulin(β2-MG), cystatin C(Cys C), superoxide dismutase(SOD), glutathione peroxidase(GSH-Px), malondialdehyde(MDA), Caspase3 and Caspase9 kits were used to detect the corresponding indicators respectively. The contents of Cd~(2+) and Zn~(2+) in serum and kidney were detected by graphite furnace atomic absorption spectrometry.The levels of kidney coefficient and BUN, Scr, β2-MG were 1.36±0.10, (19.34±0.63)mmol/L, (61.30±2.04)mmol/L and(1.02±0.10)g/mL respectively in CdCl_(2 )group, which were higher than those in the control group and VC group(Plt;0.05). The levels of the above four indexes in VC+CdCl_(2 )group were 1.09±0.10, (9.65±0.50)mmol/L, (41.85±1.27)mmol/L and(0.61±0.01)g/mL respectively, which were lower than those in CdCl_2 group(Plt;0.05). CdCl_2 exposure resulted in unclear glomerular contour, swelling of renal tubules, interstitial hyperemia, and exfoliated epithelial cells in the lumen. VC pretreatment could improve the above changes. The levels of Cd~(2+) in serum and renal tissue of mice in CdCl_2 group were(4.36±0.07)μg/L, (18.6±1.95)μg/g respectively, which were higher than that of control group and VC group(Plt;0.05), in VC+CdCl_2 group, the level were(2.12±0.06)μg/L and(2.18±0.09)μg/g, they were lower than that of CdCl_2 group(Plt;0.05). The level of serum Zn~(2+ )in CdCl_2 group was(11.35±1.03)μg/L, that was lower than control group(Plt;0.05). The level of serum Zn~(2+) in VC+CdCl_2 group was(26.98±3.13)μg/L, which was higher than that of CdCl_2 group(Plt;0.05). The levels of ROS, MDA, Caspase3 and Caspase9 in kidney tissue of mice in CdCl_2 group were(1.86±0.13), (4.78±0.15)nmol/mg, 1.50±0.24 and 1.69±0.17 respectively, which were higher than those in control group(Plt;0.05). And the level of GSH-Px was(261.3±23.36)U/mg, it was lower than that in control group(Plt;0.05). Compared with the CdCl_2 group, the levels of ROS, MDA, Caspase3 and Caspase9 in VC+CdCl_2 group decreased, and the level of GSH-Px increased, the difference was statistically significant(Plt;0.05).CdCl_2 exposure can lead to oxidative stress, damage of glomerulus and renal tubules, imbalance of zinc ion homeostasis, and damage of renal function. VC pretreatment can reduce the damage caused by CdCl_2 to a certain extent.

Neuroinflammation is a key mechanism underlying the cognitive impairment induced by PM

The hexavalent form of chromium, Cr (VI), has been associated with various diseases in humans. In this study, we examined the mechanisms underlying the effect of Cr (VI) on glucose and lipid metabolism in vivo and in vitro. We found that Cr (VI) induced abnormal liver function, increased fasting blood glucose (FBG), as well as glucose and insulin intolerance in mice. Furthermore, Cr (VI) decreased glucose-6-phosphate (G6P) level and glucose transporter-2 (GLUT2) expression, increased the levels of triglyceride (TG), low-density lipoprotein-cholesterol (LDL-C), reduced high-density lipoprotein-cholesterol (HDL-C), and increased sterol regulatory element-binding proteins 1 (SREBP1) and fat synthase (FAS) in vitro and in vivo. Moreover, Cr (VI) promoted intracellular ROS production in vitro, and induced reduction of antioxidant enzyme level and Nrf2/HO-1 expression in vitro and in vivo. Also, N-acetyl cysteine (NAC, effective antioxidant and free radical scavenger) pretreatment inhibited the production of intracellular ROS, significantly suppressed Cr (VI)-induced oxidative stress, lipid accumulation, decreased G6P and GLUT2, and improved impaired glucose tolerance and glucose and insulin intolerance caused by Cr (VI) in mice. Dh404 activated expression of Nrf2 decreased ROS level, increased HO-1 expression, ameliorated activity of the antioxidant enzyme, inhibited Cr (VI) increase of SREBP1, FAS level, and reduction of G6P and GLUT2. To sum up, these data suggest that dysregulation of ROS/Nrf2/HO-1 has an important role in Cr (VI)-induced glucose/lipid metabolic disorder.

Gestational exposure to PM

Alzheimer’s disease (AD) is a type of neurodegenerative disorder and the most common form of dementia. MicroRNA (miRNA) has been shown to play a role in various diseases, including AD. It also has been reported to regulate autophagy. We extracted miRNA from blood samples and constructed an miRNA-101a lentivirus vector. In this study we found the level of miRNA-101a was significantly reduced in the plasma of patients with AD and APPswe/PS1ΔE9 transgenic mice. The relative expression of miRNA-101a exhibited a relatively high diagnostic performance (area under receiver operating characteristic curve: 0.8725) in the prediction of AD with a sensitivity of 0.913 and a specificity of 0.733 at the threshold of 0.6463. Under electron microscopy, autophagic vacuoles in AD-related cells numbered more than the cells up-regulating miRNA-101a in the in vitro experiments. Dual-luciferase reporter assay and Western blot results proved that the MAPK1 pathway plays a role in the formation of autophagic vacuoles in AD. This study found that the autophagy phenomenon regulated by miRNA-101a via the MAPK pathway might be a new mechanism in AD. This could provide new insights into AD formation and treatment.

Air pollution is a serious environmental health problem closely related to the occurrence of central nervous system diseases. Exposure to particulate matter with an aerodynamic diameter less than or equal to 2.5 µm (PM2.5) during pregnancy may affect the growth and development of infants. The present study was to investigate the effects of maternal exposure to PM2.5 during pregnancy on brain development in mice offspring. Pregnant mice were randomly divided into experimental groups of low-, medium-, or high-dosages of PM2.5, a mock-treated group which was treated with the same amount of phosphate buffer solution (PBS), and acontrol group which was untreated. The ethology of offspring mice on postnatal days 1, 7, 14, 21, and 30, along with neuronal development and apoptosis in the cerebral cortex were investigated. Compared with the control, neuronal mitochondrial cristae fracture, changed autophagy characteristics, significantly increased terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) positive cell rate, and mRNA levels of apoptosis-related caspase-8 and caspase-9 were found in cerebral cortex of mice offspring from the treatment groups, with mRNA levels of Bcl-2 and ratio of Bcl-2 to Bax decreased. Treatment groups also demonstrated enhanced protein expressions of apoptosis-related cleaved caspase-3, cleaved caspase-8 and cleaved caspase-9, along with declined proliferating cell nuclear antigen (PCNA), Bcl-2, and ratio of Bcl-2 to Bax. Open field experiments and tail suspension experiments showed that exposure to high dosage of PM2.5 resulted in decreased spontaneous activities but increased static accumulation time in mice offspring, indicating anxiety, depression, and social behavioral changes. Our results suggested that maternal exposure to PM2.5 during pregnancy might interfere with cerebral cortex development in mice offspring by affecting cell apoptosis.

The objective of this study was to observe the effects of moderate-intensity training on the activity of heme oxygenase (HO) and expression of HO-1 mRNA in the aorta and the cardiac muscle of spontaneously hypertensive rats (SHRs). After 9 weeks of swimming exercise, the activity of HO and expression of HO-1 mRNA in the SHRs were measured. The resting blood pressure in the exercise group was increased by 1.7% (P > 0.05), whereas it was significantly elevated by 10.3% (P < 0.01) in the SHR rats. Compared with animals in the control and sedentary groups, the expression level of HO-1 mRNA of aorta and cardiac muscle in the exercise group was significantly enhanced (P < 0.01). The HO activity and the content of plasma carbon monoxide (CO) in the sedentary group were dramatically decreased (P < 0.05 and P < 0.01, respectively) compared with the control group. HO activity and content of plasma CO in the exercise group were significantly higher compared with those in the sedentary group (P < 0.05 and P < 0.01, respectively). The HO/CO metabolic pathway might be involved in the regulation of blood pressure of the SHR models.