AIM: To evaluate the role of intestinal endotoxemia in the genesis of hepatopulmonary syndrome. METHODS: A rat model of cirrhosis was prepared with the method of compound factors. At the end of the eighth week, rats w...AIM: To evaluate the role of intestinal endotoxemia in the genesis of hepatopulmonary syndrome. METHODS: A rat model of cirrhosis was prepared with the method of compound factors. At the end of the eighth week, rats with cirrhosis were treated with 300 μg LPS/100 g body weight, and 1 g/rat of glycine about four h prior to LPS. After three h of LPS treatment, blood and tissues were collected for various measurements. Kupffer cells were isolated from male Wistar rats and cultured, and divided into five groups. Supernatant was harvested at 3 h after treatment with LPS for measurement of tumor necrosis factor-alpha (TNF-α). RESULTS: Our results showed that in rats with cirrhosis, slowed and deepened breath with occasional pause was. PaO2, PaCO2 and standard bicarbonate (SB) in arterial blood were decreased. Arterial O2 and actual bicarbonate (AB) were markedly decreased. There was a close correlation between decreased O2 and endotoxin. Metabolic acidosis accompanying respiratory alkalosis was the primary type of acid-base imbalance. The alveolar-arterial oxygen gradient was sharply widened. Massive accumulation of giant macrophages in the alveolar spaces and its wall and widened alveolar wall architecture were observed. The number of bacterial translocations in mesenteric lymph nodes increased. The ratio of TC99M-MAA brain-over-lung radioactivity rose. Endotoxin, and TNF-α, endothelin-1 (ET-1), nitric oxide (NO) in plasma and ET-1, carbon monoxide (CO) in lung homogenates increased. After administration of a given dosage of LPS in rats with cirrhosis, various pathological parameters worsened. Plasma level of endotoxin was related to TNF-α, ET-1, NO in plasma and ET-1, NO, CO in lung homogenates. TNF-α level was related to ET-1 and NO in plasma and lung homogenates and CO in lung homogenate as well. The level of TNF-α increased after infusion of LPS into culture supernatant of Kupffer cells in vitro. However, TNF-α significantly decreased after pretreatment with glycine, PD98059 and SB212850. Glycine could antagonize the effect of LPS in vivo and in vitro. CONCLUSION: Intestinal endotoxemia accompanying by cirrhosis may be an important mechanism in the development of hepatopulmonary syndrome in rats. Overproduction of TNF-α due to endotoxin stimulation of Kupffer cells via mitogen-activated protein kinase (MAPK) signal transduction pathway may be a major mechanism mediating the pathologic alterations of hepatopulmonary syndrome.展开更多
Upon activation, tumor necrosis factor alpha （TNF-α） receptor can engage apoptotic or survival pathways. Inhibition of macromolecular synthesis is known to sensitize cells to TNF-α-induced cell death. It is believ...Upon activation, tumor necrosis factor alpha （TNF-α） receptor can engage apoptotic or survival pathways. Inhibition of macromolecular synthesis is known to sensitize cells to TNF-α-induced cell death. It is believed that this sensitization is due to the transcriptional blockade of genes regulated by NF-κB. Nevertheless, such evidence has remained elusive in the nervous system. Here, we show that TNF-α cannot normally induce apoptosis in PC12 cells or cortical neurons. However, cells treated with Actinomycin D （ActD） become susceptible to TNF-α-induced cell death through the activation of caspase-8, generation of tBid and activation of caspase-9 and -3. Analysis of several proteins involved in TNF-α receptor signaling showed no significant downregulation of NF-κB target genes, such as IAPs or FLIP, under such conditions. However, Bcl-XL protein levels, but not those of Bcl-2, Bax and Bak, are reduced by ActD or TNF-α/ ActD treatments. Moreover, Bcl-xL overexpression fully protects cells against TNF-α/ActD-induced cell death. When endogenous levels of Bcl-XL are specifically downregulated by lentiviral-based RNAi, cells no longer require ActD to be sensitive to TNF-α-triggered apoptosis. Furthermore, Bcl-xL downregulation does not affect TNF-α-mediated NF-κB activation. Altogether, our results demonstrate that Bcl-XL, and not Bci-2, FLIP or IAPs, acts as the endogenous regulator of neuronal resistance/sensitivity to TNF-α-induced apoptosis in an NF-κB-independent manner.展开更多
Dynamic regulation of histone methylation/demethylation plays an important role during development. Mutations and truncations in human plant homeodomain （PHD） finger protein 8 （PHF8） are associated with X-linked m...Dynamic regulation of histone methylation/demethylation plays an important role during development. Mutations and truncations in human plant homeodomain （PHD） finger protein 8 （PHF8） are associated with X-linked mental retardation and facial anomalies, such as a long face, broad nasal tip, cleft lip/cleft palate and large hands, yet its molecular function and structural basis remain unclear. Here, we report the crystal structures of the catalytic core of PHF8 with or without α-ketoglutarate （α-KG） at high resolution. Biochemical and structural studies reveal that PHF8 is a novel histone demethylase specific for di- and mono-methylated histone H3 lysine 9 （H3K9me2/1）, but not for H3K9me3. Our analyses also reveal how human PHF8 discriminates between methylation states and achieves sequence specificity for methylated H3K9. The in vitro demethylation assay also showed that the F279S mutant observed in clinical patients possesses no demethylation activity, suggesting that loss of enzymatic activity is crucial for pathogenesis of PHF8 patients. Taken together, these results will shed light on the molecular mechanism underlying PHF8-associated developmental and neurological diseases.展开更多
Since 2003, the sites of the national environmental monitoring system （DNSE） of Niger, set up by the long term ecological monitoring observatories network （ROSELT） with the support of the Sahel and Sahara Observat...Since 2003, the sites of the national environmental monitoring system （DNSE） of Niger, set up by the long term ecological monitoring observatories network （ROSELT） with the support of the Sahel and Sahara Observatory （OSS）, were used to collect ecological data with harmonized methods for spatio-temporal comparisons purpose. Floristic and phytoecological data were collected using the phytosociological methodology of Braun-Blanquet （1932）. Ecosystem vital attributes used included the specific diversity, alpha diversity, equidistribution, biological types and herbaceous phytomass. At the whole system scale, the analysis revealed that the specific diversity, the alpha diversity and the phytomass values were higher in less disturbed biotopes of the north soudanian and south sahelian bioclimates where the rainfall rate is relatively high. Regarding the north sahelian and saharian bioclimates, the topography may play a critical role in the redistribution of this phytodiversity. Besides, the distribution of the biological types showed the prevalence of therophytes （56.8 ± 11%） regardless of the bioclimate and, to a lesser extent, the perennial species （26.5 ± 7.3%）, the later group showing higher values for the north soudanian bioclimate.展开更多
α-Ketoacids （KAs） are widely used in chronic kidney disease （CKD）, but their efficacy is not clear. Therefore, we conducted a systematic review of the benefits of KAs. Two reviewers independently searched MEDLINE...α-Ketoacids （KAs） are widely used in chronic kidney disease （CKD）, but their efficacy is not clear. Therefore, we conducted a systematic review of the benefits of KAs. Two reviewers independently searched MEDLINE, EMBASE, the Cochrane library （http：//www.cochrane.org）, CNKI, and Wan Fang databases from inception to May 31, 2016 for randomized controlled trials （RCTs） comparing K.As plus low protein diet （LPD） with LPD only on CKD patients. Statistical analyses were performed using both a random effects model and a fixed effects model with Rev Man 5.3, followed by sensitivity analysis. We identified 21 randomized controlled trials that enrolled a total of 1448 patients. 726 had received LPD plus KAs and 722 had received only LPD. Compared with simply using of LPD, combining with KAs could decrease serum creatinine （95% CI, 0.46-0.96; P〈0.00001）, serum cholesterol （95% CI, 0.24±3.77; P = 0.02）, serum LDL cholesterol （95% CI, 0.12-0.54; P = 0.31）, and serum triglyceride （95% CI, 0.28--0.83; P = 0.02） while increasing serum HDL cholesterol （95% CI, -1.73-0.07; P〈0.00001）. Likewise, a decrease in p3 （95% CI, 0.90-1.26; P〈0.00001） and PTH （95% CI, 0.70-1.21; P = 0.007） were observed. No hypercalcemia and other ARD or toxicity was reported, which indicated the safety of KAs. Nevertheless, the studies were pooled with considerable heterogeneity. In patients with CKD, there was low-quality evidence suggesting that KAs may perform an additive effect on the improvement of renal function, lipid profile, as well as the correction of calcium-phosphate metabolism disorders. On account of the considerable heterogeneity of the meta-analysis and the costly price and adherence of KAs administration, K.As＇ roles in the management of mild or moderate CKD patients may need more RCTs of large scale and high quality to confirm.展开更多
文摘AIM: To evaluate the role of intestinal endotoxemia in the genesis of hepatopulmonary syndrome. METHODS: A rat model of cirrhosis was prepared with the method of compound factors. At the end of the eighth week, rats with cirrhosis were treated with 300 μg LPS/100 g body weight, and 1 g/rat of glycine about four h prior to LPS. After three h of LPS treatment, blood and tissues were collected for various measurements. Kupffer cells were isolated from male Wistar rats and cultured, and divided into five groups. Supernatant was harvested at 3 h after treatment with LPS for measurement of tumor necrosis factor-alpha (TNF-α). RESULTS: Our results showed that in rats with cirrhosis, slowed and deepened breath with occasional pause was. PaO2, PaCO2 and standard bicarbonate (SB) in arterial blood were decreased. Arterial O2 and actual bicarbonate (AB) were markedly decreased. There was a close correlation between decreased O2 and endotoxin. Metabolic acidosis accompanying respiratory alkalosis was the primary type of acid-base imbalance. The alveolar-arterial oxygen gradient was sharply widened. Massive accumulation of giant macrophages in the alveolar spaces and its wall and widened alveolar wall architecture were observed. The number of bacterial translocations in mesenteric lymph nodes increased. The ratio of TC99M-MAA brain-over-lung radioactivity rose. Endotoxin, and TNF-α, endothelin-1 (ET-1), nitric oxide (NO) in plasma and ET-1, carbon monoxide (CO) in lung homogenates increased. After administration of a given dosage of LPS in rats with cirrhosis, various pathological parameters worsened. Plasma level of endotoxin was related to TNF-α, ET-1, NO in plasma and ET-1, NO, CO in lung homogenates. TNF-α level was related to ET-1 and NO in plasma and lung homogenates and CO in lung homogenate as well. The level of TNF-α increased after infusion of LPS into culture supernatant of Kupffer cells in vitro. However, TNF-α significantly decreased after pretreatment with glycine, PD98059 and SB212850. Glycine could antagonize the effect of LPS in vivo and in vitro. CONCLUSION: Intestinal endotoxemia accompanying by cirrhosis may be an important mechanism in the development of hepatopulmonary syndrome in rats. Overproduction of TNF-α due to endotoxin stimulation of Kupffer cells via mitogen-activated protein kinase (MAPK) signal transduction pathway may be a major mechanism mediating the pathologic alterations of hepatopulmonary syndrome.
文摘Upon activation, tumor necrosis factor alpha （TNF-α） receptor can engage apoptotic or survival pathways. Inhibition of macromolecular synthesis is known to sensitize cells to TNF-α-induced cell death. It is believed that this sensitization is due to the transcriptional blockade of genes regulated by NF-κB. Nevertheless, such evidence has remained elusive in the nervous system. Here, we show that TNF-α cannot normally induce apoptosis in PC12 cells or cortical neurons. However, cells treated with Actinomycin D （ActD） become susceptible to TNF-α-induced cell death through the activation of caspase-8, generation of tBid and activation of caspase-9 and -3. Analysis of several proteins involved in TNF-α receptor signaling showed no significant downregulation of NF-κB target genes, such as IAPs or FLIP, under such conditions. However, Bcl-XL protein levels, but not those of Bcl-2, Bax and Bak, are reduced by ActD or TNF-α/ ActD treatments. Moreover, Bcl-xL overexpression fully protects cells against TNF-α/ActD-induced cell death. When endogenous levels of Bcl-XL are specifically downregulated by lentiviral-based RNAi, cells no longer require ActD to be sensitive to TNF-α-triggered apoptosis. Furthermore, Bcl-xL downregulation does not affect TNF-α-mediated NF-κB activation. Altogether, our results demonstrate that Bcl-XL, and not Bci-2, FLIP or IAPs, acts as the endogenous regulator of neuronal resistance/sensitivity to TNF-α-induced apoptosis in an NF-κB-independent manner.
基金Supplementary information is linked to the online version of the paper on the Cell Research website.Acknowledgments We thank Dr Dawei Li （China Agricultural University） for generously providing us with the experimental conditions during the early stages of this project. We thank Dr Ruiming Xu （Institute of Biophysics, Chinese Academy of Sciences） for critical reading of this manuscript and advice. We thank Dr Pinchao Mei （Chinese Academy of Medical Sciences and Peking Union Medical College）, Xinqi Liu （Nankai University） and Jiemin Wong （East China Normal University） for discussions and advice. The synchrotronradiation experiments were performed at Shanghai Synchrotron Radiation Facility （SSRF） and NE3A in the Photon Factory. Z.C. is supported by the National Basic Research Program of China （973 Program, 2009CB825501）, the National Natural Science Foundation of China （30870494 and 90919043）, the New Century Excellent Talents in University （NCET-07-0808） and the Innovative Project of SKLAB. S. H. is supported by the National Key Laboratory Special Fund 2060204. Z. D. is supported by the National Natural Science Foundation of China （J0730639）.
文摘Dynamic regulation of histone methylation/demethylation plays an important role during development. Mutations and truncations in human plant homeodomain （PHD） finger protein 8 （PHF8） are associated with X-linked mental retardation and facial anomalies, such as a long face, broad nasal tip, cleft lip/cleft palate and large hands, yet its molecular function and structural basis remain unclear. Here, we report the crystal structures of the catalytic core of PHF8 with or without α-ketoglutarate （α-KG） at high resolution. Biochemical and structural studies reveal that PHF8 is a novel histone demethylase specific for di- and mono-methylated histone H3 lysine 9 （H3K9me2/1）, but not for H3K9me3. Our analyses also reveal how human PHF8 discriminates between methylation states and achieves sequence specificity for methylated H3K9. The in vitro demethylation assay also showed that the F279S mutant observed in clinical patients possesses no demethylation activity, suggesting that loss of enzymatic activity is crucial for pathogenesis of PHF8 patients. Taken together, these results will shed light on the molecular mechanism underlying PHF8-associated developmental and neurological diseases.
文摘Since 2003, the sites of the national environmental monitoring system （DNSE） of Niger, set up by the long term ecological monitoring observatories network （ROSELT） with the support of the Sahel and Sahara Observatory （OSS）, were used to collect ecological data with harmonized methods for spatio-temporal comparisons purpose. Floristic and phytoecological data were collected using the phytosociological methodology of Braun-Blanquet （1932）. Ecosystem vital attributes used included the specific diversity, alpha diversity, equidistribution, biological types and herbaceous phytomass. At the whole system scale, the analysis revealed that the specific diversity, the alpha diversity and the phytomass values were higher in less disturbed biotopes of the north soudanian and south sahelian bioclimates where the rainfall rate is relatively high. Regarding the north sahelian and saharian bioclimates, the topography may play a critical role in the redistribution of this phytodiversity. Besides, the distribution of the biological types showed the prevalence of therophytes （56.8 ± 11%） regardless of the bioclimate and, to a lesser extent, the perennial species （26.5 ± 7.3%）, the later group showing higher values for the north soudanian bioclimate.
文摘α-Ketoacids （KAs） are widely used in chronic kidney disease （CKD）, but their efficacy is not clear. Therefore, we conducted a systematic review of the benefits of KAs. Two reviewers independently searched MEDLINE, EMBASE, the Cochrane library （http：//www.cochrane.org）, CNKI, and Wan Fang databases from inception to May 31, 2016 for randomized controlled trials （RCTs） comparing K.As plus low protein diet （LPD） with LPD only on CKD patients. Statistical analyses were performed using both a random effects model and a fixed effects model with Rev Man 5.3, followed by sensitivity analysis. We identified 21 randomized controlled trials that enrolled a total of 1448 patients. 726 had received LPD plus KAs and 722 had received only LPD. Compared with simply using of LPD, combining with KAs could decrease serum creatinine （95% CI, 0.46-0.96; P〈0.00001）, serum cholesterol （95% CI, 0.24±3.77; P = 0.02）, serum LDL cholesterol （95% CI, 0.12-0.54; P = 0.31）, and serum triglyceride （95% CI, 0.28--0.83; P = 0.02） while increasing serum HDL cholesterol （95% CI, -1.73-0.07; P〈0.00001）. Likewise, a decrease in p3 （95% CI, 0.90-1.26; P〈0.00001） and PTH （95% CI, 0.70-1.21; P = 0.007） were observed. No hypercalcemia and other ARD or toxicity was reported, which indicated the safety of KAs. Nevertheless, the studies were pooled with considerable heterogeneity. In patients with CKD, there was low-quality evidence suggesting that KAs may perform an additive effect on the improvement of renal function, lipid profile, as well as the correction of calcium-phosphate metabolism disorders. On account of the considerable heterogeneity of the meta-analysis and the costly price and adherence of KAs administration, K.As＇ roles in the management of mild or moderate CKD patients may need more RCTs of large scale and high quality to confirm.
