Objective To elucidate the molecular mechanism of sirtuin-3 (SIRT3) in regulating mitochondrial biogenesis in human renal tubular epithelial cells. Methods Cells were stimulated with different concentrations of H₂O₂ and divided into four groups: control (NC), 50 μmol/L H₂O₂, 110 μmol/L H₂O₂ and 150 μmol/L H₂O₂. SIRT3 protein expression was then measured. SIRT3 was knocked down with siRNA, and cells were further assigned to five groups: control (NC), negative-control siRNA (NCsi), SIRT3-siRNA (siSIRT3), NCsi+H₂O₂, and siSIRT3+H₂O₂. After 24 h, cellular adenosine triphosphate (ATP) and mitochondrial superoxide anion (O₂•⁻) levels were determined, together with mitochondrial expression of SIRT3, peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), nuclear respiratory factor 1 (NRF1), mitochondrial transcription factor A (TFAM), superoxide dismutase 2 (SOD2), acetylated-SOD2 and adenosine monophosphate activated protein kinase α1 (AMPKα1). Results The 110 and 150 μmol/L H₂O₂ decreased SIRT3 protein (both P<0.05). ATP and mitochondrial O₂•⁻ did not differ between NC and NCsi groups (both P>0.05). Compared to the NCsi group, the siSIRT3 group exhibited elevated O₂•⁻ level, decreased SIRT3 protein and increased expression levels of SOD2 and acetylated SOD2 protein (all P<0.05). Compared to the NCsi group, the NCsi+H₂O₂ group exhibited decreased cellular ATP levels, elevated mitochondrial O₂•⁻ levels, and reduced protein expression levels of SIRT3, SOD2, TFAM, AMPKα1, PGC-1α and NRF1 (all P<0.05). Compared with the siSIRT3 group, the siSIRT3+H₂O₂ group showed a decrease in cellular ATP levels, an increase in mitochondrial O₂•⁻ levels, a decrease in SIRT3, SOD2, TFAM, AMPKα1, PGC-1α and NRF1 protein expression levels and a decrease in acetylated SOD2 protein expression levels (all P<0.05). Compared with the NCsi+H₂O₂ group, the siSIRT3+H₂O₂ group showed a decrease in cellular ATP levels, an increase in mitochondrial O₂•⁻ levels, a decrease in SIRT3, AMPKα1, PGC-1α and NRF1, TFAM protein expression levels, and an increase in SOD2 and acetylated SOD2 protein expression levels (all P<0.05). Conclusions SIRT3 promotes mitochondrial biogenesis in tubular epithelial cells via the AMPK/PGC-1α/NRF1/TFAM axis, representing a key mechanism through which SIRT3 ameliorates oxidative stress-induced mitochondrial dysfunction.

Objective To investigate the effects of methionine restriction(MR)on macrophages in lipopolysaccharide(LPS)-induced acute lung injury(ALI)and to explore the underlying mechanism.Methods According to the random number table method,36 male C57BL/6J mice(6～8 weeks old,23±2 g)were divided into 3 groups with 12 mice in each group:the sham group,the LPS group and the LPS+MR group.HE staining and pathological scoring of lung injury were performed in lung tissues.The expression of LPS-binding protein(LBP)and Toll-like receptor-4(TLR4)was detected by RT-qPCR and Western blotting.Macrophage-colony stimulating factor(M-CSF),granulocyte-macrophage-colony stimulating factor(GM-CSF)and chemokine C-C motif ligand 3(CCL3)which are all macrophage-associated chemokines were analyzed by immunohistochemistry.Results Compared with the sham group,the pathological score of lung injury in the LPS group was significantly increased(P＜0.01);The mRNA and protein expression levels of LBP and TLR4 were significantly increased;The number of positive cells of CD11b,F4/80,M-CSF,GM-CSF and CCL3 were significantly increased(P＜0.01).MR significantly improved LPS-induced ALI,and decreased the pathological score of lung injury(P＜0.01);The mRNA and protein expression levels of LBP and TLR4 were decreased;Compared with the LPS group,the number of positive cells of CD11 b,F4/80,M-CSF,GM-CSF and CCL3 were reduced in the LPS+MR group(P＜0.01).Conclusion MR could attenuate LPS-induced ALI by inhibiting the expression of macrophage chemokines and preventing infiltration and activation of macrophage to lungs.

Objective To investigate the impact and mechanism of efaproxiral (RSR13),a hemoglobin allosteric agent,on lung injury in rats caused by explosion-induced shock waves in plateau areas. Methods Eighty-two healthy male SD rats (8-week-old,transferred from an altitude of 2 880 m to 4700 m within 6 h)were randomly divided into blast injury group and RSR13+blast injury group (intraperitoneal injection of 150 mg/kg RSR132 h before explosion).Sixty rats were positioned at 5 m from the explosion source and divided into 5-m blast injury group (n=30)and 5-m RSR13+blast injury group (n=30). Additionally,16 rats were positioned at 6 m from the explosion source and then assigned into 6-m blast injury group (n=8)and 6-m RSR13+blast injury group (n=8).The left 6 rats served as control (n=6).Survival outcomes of each rat group positioned 5 m from the explosion source were observed over a 24-hour period.HE staining was used to evaluate the pathological score of the surviving rats positioned at 6 m from the explosion source in 24 h after explosion,along with arterial blood gas analysis.The contents of glutathione (GSH),malondialdehyde (MDA ) and superoxide dismutase (SOD ) in the lung tissues were determined by colorimetry.Western blotting was conducted to measure the expression levels of cleaved caspase-3 and occludin in the lung tissue.Results RSR13 pretreatment increased the survival rate immediately after explosion (93.3％ vs 46.7％,P<0.01 )and at 1 h after explosion (86.7％ vs 46.7％,P<0.01 )in plateau areas of 5 m from the explosion source.At high altitude,RSR13 pretreatment reduced the pathological score of lung injury in rats 6 m away from the explosion source (8.27±0.93 vs 13.70±0.78,P<0.01 ),but had no significant effect on the results of arterial blood gas analysis in rats with lung blast injury (P>0.05 ).In addition,RSR13 pretreatment also increased GSH content (40.27±12.47 vs 22.62±10.88 μg/g,P<0.05),but showed no obvious effect on MDA content and SOD activity (P>0.05 ),decreased the protein level of cleaved caspase-3 (P<0.01 )and increased that of occludin (P<0.05 )in the lung tissues.Conclusion RSR13 exerts significant protective effect on lung injury in rats caused by explosion-induced shock waves in high-altitude environment,which may be related to its increasing antioxidant capacity,reducing cell apoptosis and decreasing barrier permeability of lung ventilation.

Objective:To investigate the expression levels of interferon-α receptor (IFNAR), interferon-stimulated gene factor 3(ISGF3), double-stranded RNA-activated protein kinase(PKR) and ribonuclease L (RNase L) in patients with chronic hepatitis B (CHB) treated with interferon.Methods:From July 2014 to June 2017, 41 treatment naive CHB patients were enrolled in the Department of Infectious Diseases, First Affiliated Hospital of Nanchang University. Eighteen patients were treated with polyethylene glycol interferon α-2b, and 23 patients were treated with conventional interferon. The mRNA and protein expression levels of IFNAR1, IFNAR2, ISGF3, PKR and RNase L in peripheral blood mononuclear cells (PBMC) were detected by reverse transcription polymerase chain reaction and Western blot, respectively. The differences of these molecular expression levels in PBMC between the effective and ineffective groups were compared. The data were analyzed by t test. Results:After 24 weeks of treatment, 25 cases were effective, while 16 cases were ineffective. At four weeks of treatment, the mRNA expression levels of IFNAR1, IFNAR2 and PKR in PBMC of the effective group were 0.748±0.129, 1.169±0.125 and 1.047±0.091, respectively, which were all higher than those in the ineffective group (0.591±0.021, 0.689±0.059 and 0.791±0.033, respectively). The differences were statistically significant ( t=-4.304, 16.482 and -5.346, respectively, all P<0.01). The mRNA expressions of ISGF3 and RNase L in PBMC of the effective group were 0.739±0.159 and 0.780±0.140, respectively, while those in the ineffective group were 0.690±0.035 and 0.733±0.122, respectively, which were not significantly different ( t=-0.160 and -1.443, respectively, both P>0.05). The mRNA expression levels of IFNAR1, IFNAR2, ISGF3, PKR and RNase L at baseline, week eight, 12 and 24 of treatment in the effective group were all higher than those in the ineffective group (all P<0.01). The protein expression levels of IFNAR1, IFNAR2, ISGF3, PKR and RNase L in the effective group were all higher than those in the ineffective group (all P<0.01). Conclusion:After interferon treatment, the mRNA and protein expression levels of IFNAR1, IFNAR2, ISGF3, PKR and RNase L in PBMC of CHB patients are all increased, especially IFNAR2 and PKR levels increase in the early stage of treatment (four weeks).