Transcutaneous Electrical Acupoints Stimulation Improves Spontaneous Voiding Recovery After Laparoscopic Cholecystectomy: A Randomized Clinical Trial.

BACKGROUND: Facilitating the recurrence of spontaneous voiding is considered to be a way to prevent urinary retention after surgery, which is of great importance in cholecystectomy. This study aimed to assess the effect of transcutaneous electrical acupoint stimulation (TEAS) on spontaneous voiding recovery after laparoscopic cholecystectom. METHODS: Participants who underwent elective laparoscopic cholecystectomy were randomly assigned to either the TEAS group or the sham group. Active TEAS or sham TEAS at specific acupuncture points was conducted intraoperatively and postoperatively. The primary outcome was the recovery speed of spontaneous voiding ability after surgery and secondary outcomes included postoperative urinary retention (POUR), voiding dysfunction, pain, anxiety and depression, and early recovery after surgery. RESULTS: A total of 1,948 participants were recruited and randomized to TEAS (n = 975) or sham (n = 973) between August 2018 and June 2020. TEAS shortens the time delay of the first spontaneous voiding after laparoscopic cholecystectomy (5.6 h [IQR, 3.7-8.1 h] in the TEAS group vs 7.0 h [IQR, 4.7-9.7 h] in the sham group) (p < 0.001). The TEAS group experienced less POUR (p = 0.020), less voiding difficulty (p < 0.001), less anxiety and depression (p < 0.001), reduced pain (p = 0.007), and earlier ambulation (p = 0.01) than the sham group. CONCLUSIONS: Our results showed that TEAS is an effective approach to accelerate the recovery of spontaneous voiding and reduce POUR which facilitates recovery for patients after laparoscopic cholecystectomy.

Effect of grazing disturbance on floral display, pollen limitation and plant pollination efficiency in the desert steppe.

BACKGROUND: Grazing disturbance usually affects floral display and pollination efficiency in the desert steppe, which may cause pollen limitation in insect-pollinated plants. Effective pollination is essential for the reproductive success of insect-pollinated plants and insufficient pollen transfer may result in pollen limitation. Caragana microphylla Lam is an arid region shrub with ecological importance. Few studies have been conducted on how grazing disturbance influences pollen limitation and pollination efficiency of C. microphylla. Here, we quantify the effect of different grazing intensities on floral display, pollinator visitation frequency and seed production in the Urat desert steppe. RESULTS: In C. microphylla, supplemental hand pollination increased the seed set, and pollen limitation was the predominant limiting factor. As the heavy grazing significantly reduced the seed set in plants that underwent open-pollination, but there was no significant difference in the seed set between plants in the control plots and plants in the moderate grazing plots. Furthermore, there was a higher pollinator visitation frequency in plants in the control plots than in plants in the heavy grazing plots. CONCLUSIONS: We found that pollinator visitation frequency was significantly associated with the number of open flowers. Our findings also demonstrated that seed production is associated with pollinator visitation frequency, as indicated by increased seed production in flowers with higher pollinator visitation frequency. Therefore, this study provides insight into the effect of different grazing intensities on floral display that are important for influencing pollinator visitation frequency and pollination efficiency in desert steppes.

Carbon monoxide attenuates lipopolysaccharide-induced lung injury by mitofusin proteins via p38 MAPK pathway.

BACKGROUND: The protective effects of carbon monoxide against the lipopolysaccharide (LPS)-induced lung injury were attributed to maintenance of mitochondrial dynamics, but the mechanisms remain unexplored. MATERIALS AND METHODS: Using a rat model of acute lung injury induced by LPS and the LPS attacking cell model, we investigated the effects of pretreatment of carbon monoxide molecule-2 (CORM-2) on the acute lung injury and expressions of mitofusin proteins that play a critical role in mitochondrial dynamics. RESULTS: We found that preadministration of CORM-2, not the inactive form of CORM-2, significantly reduced the lung injury, levels of inflammatory cytokines, and the degree of oxidative stress caused by LPS. What was more, it increased the expressions of mitofusin proteins. Similar findings were also found in LPS-stimulating cell model. However, when the cells were treated in combination with LPS, CORM-2, and SB203580, it completely abolished the protection of CORM-2, reflected by increased levels of inflammatory cytokines and malonaldehyde, decreased activities of superoxide dismutase, along with the lower expressions of mitofusin proteins and the ratio of p-p38 mitogen activated protein kinase to p38 mitogen activated protein kinase. CONCLUSIONS: Our observations suggest that pretreatment with CORM-2 could attenuate LPS-induced lung injury by inducing the expressions of mitofusin proteins via p38 mitogen activated protein kinase pathway.

Prevalence of depressive symptoms and its correlates among medical students in China: a national survey in 33 universities.

We conducted a national survey among medical students in China to estimate the prevalence of depressive symptoms and explore associated risk factors based on an established questionnaire composed of demographic information, life events in the past four weeks before survey, and the validated Chinese version of the 21-item Beck's Depression Inventory (BDI). The mean age of enrolled 9010 students was 20.7 (standard deviation: 1.6) years. BDI scores indicated that 19.9% had depressive symptoms based on the cut-off score of 14. Socioeconomic factors and student characteristics such as male sex, low monthly income per capita, father's poor education background, and higher year of study were associated with higher prevalence of depressive symptoms among medical students. Students who studied in comprehensive universities were more likely to have depressive symptoms compared with those from medical universities. Habitual smoking and alcohol drinking, sleep deprivation, and hospitalization or medication for one week or more in the last four weeks also predisposed students to higher risk of depressive symptoms. Our results indicate that depressive symptoms are becoming a highly prevalent health problem among Chinese medical students. Primary and secondary prevention should be prioritized to tackle this issue based on potential risk factors.

Generation of fully pluripotent female murine-induced pluripotent stem cells.

The high quality of induced pluripotent stem cells (iPSCs) has been determined to be high-grade chimeras that are competent for germline transmission, and viable mice can be generated through tetraploid complementation. Most of the high-quality iPSCs described to date have been male. Female iPSCs, especially fully pluripotent female iPSCs, are also essential for clinical applications and scientific research. Here, we show, for the first time, that a gender-mixed induction strategy could lead to a skewed sex ratio of iPSCs. After reprogramming, 50%, 70%, and 90% female initiating mouse embryonic fibroblasts at different male ratios resulted in 14.1 ± 6.8% (P < 0.05), 31.8 ± 5.4% (P < 0.05), and 80.1 ± 2.8% (P < 0.05) female iPSCs, respectively. Furthermore, these female iPSCs had pluripotent properties typical of embryonic stem cells. Importantly, these fully pluripotent female iPSCs could generate viable mice by tetraploid complementation. These findings indicate that high-quality female iPSCs could be derived effectively, and suggest that clinical application of female iPSCs is feasible.

Melatonin improves the reprogramming efficiency of murine-induced pluripotent stem cells using a secondary inducible system.

This study focused on the effect of melatonin on reprogramming with specific regard to the generation of induced pluripotent stem cells (iPSCs). Here, a secondary inducible system, which is more accurate and suitable for studying the involvement of chemicals in reprogramming efficiency, was used to evaluate the effect of melatonin on mouse iPSC generation. Secondary fibroblasts collected from all-iPSC mice through tetraploid complementation were cultured in induction medium supplemented with melatonin at different concentrations (0, 10(-6), 10(-7), 10(-8), 10(-9), or 10(-10 )m) or with vitamin C (50 µg/mL) as a positive control. Compared with untreated group (0.22 ± 0.04% efficiency), 10(-8) (0.81 ± 0.04%), and 10(-9 )m (0.83 ± 0.08%) melatonin supplementation significantly improved reprogramming efficiency (P < 0.05). Moreover, we verified that the iPSCs induced by melatonin treatment (MiPSCs) had the same characteristics as typical embryonic stem cells (ESCs), including expression of the pluripotency markers Oct4, Sox2, and Nanog, the ability to form teratomas and all three germ layers of the embryo, as well as produce chimeric mice with contribution to the germ line. Interestingly, only the melatonin receptor MT2 was detected in secondary fibroblasts, while MiPSCs and ESCs expressed MT1 and MT2 receptors. Furthermore, during the early stage of reprogramming, expression of the apoptosis-related genes p53 and p21 was lower in the group treated with 10(-9) m melatonin compared with the untreated controls. In conclusion, melatonin supplementation enhances the efficiency of murine iPSC generation. These beneficial effects may be associated with inhibition of the p53-mediated apoptotic pathway.

[Effect of miR-15a on induction of apoptosis in breast cancer MCF-7 cells].

OBJECTIVE: To investigate the effect and mechanism of miR-15a on the induction of apoptosis in breast cancer cells. METHODS: To detect the expression level of miR-15a in breast cancer cell line MCF-7 cells and human mammary gland epithelial cell line MCF-10A cells by quantitative PCR. The target point of MCF-7 was predicted by software and was validated by luciferase report gene system. MiR-15a was transfected into MCF-7 cells with liposomes. The expression of Bcl-2 in MCF-7 cells was detected by Western blotting and the apoptosis rate of MCF-7 cells was detected by flow cytometry. RESULTS: The expression level of miR-15a in MCF-7 cells was lower than that in the MCF-10A cells (0.253:1, P < 0.0001). The expression of MiR-15a was significantly inhibited by Bcl-2 (P < 0.05). Compared with the control, Bcl-2 expression was significantly decreased in the MCF-7 cells. The results of flow cytometry showed that the apoptosis rate was 13.4% in non-transfected MCF-7 cells, 15.9% in MCF-7 cells transfected with control RNA, and 31.5% in MCF-7 cells transfected with miR-15a (P < 0.05), indicating an evident induction of apoptosis in the MCF-7 cells. CONCLUSION: miR-15a may have a potential application value in breast carcinoma biotherapy.

Maternally administered lipopolysaccharide (LPS) upregulates the expression of heme oxygenase-1 in fetal liver: the role of reactive oxygen species.

Heme oxygenase-1 (HO-1) is an inducible enzyme that catalyzes the rate-limiting step in the degradation of heme to biliverdin, carbon monoxide and iron. Previous studies have demonstrated that lipopolysaccharide (LPS) upregulates the expression of HO-1 in adult mouse liver. The present study aimed to investigate the effects of maternal LPS exposure on the expression of HO-1 in fetal liver. The pregnant mice were intraperitoneally injected with different doses of LPS (1, 10, 75 microg/kg) on gestational day 17. Results showed that the expression of HO-1 in fetal liver was increased, beginning 2h after LPS, being at the highest level 24h after LPS, and remaining elevated up to 48h after LPS, whereas HO-2, the constitutive form, did not change at the various time points observed. LPS-induced upregulation of HO-1 was blocked by alpha-phenyl-N-t-butylnitrone (PBN), a free radical spin trapping agent. Correspondingly, PBN pretreatment significantly attenuated LPS-induced lipid peroxidation and glutathione (GSH) depletion in fetal liver. However, aminoguanidine (AG), a selective inhibitor of inducible nitric oxide synthase (iNOS), and pentoxifylline (PTX), an inhibitor of tumor necrosis factor alpha (TNF-alpha) synthesis, had no effect on LPS-induced upregulation of HO-1 in fetal liver. In conclusion, reactive oxygen species (ROS), rather than TNF-alpha or nitric oxide (NO), are involved in LPS-induced upregulation of HO-1 in fetal liver. These results provide new evidence that maternal LPS exposure results in oxidative stress in fetuses, which may contribute to LPS-induced developmental toxicity.

Maternally-administered lipopolysaccharide (LPS) increases tumor necrosis factor alpha in fetal liver and fetal brain: its suppression by low-dose LPS pretreatment.

Lipopolysaccharide (LPS) has been associated with adverse developmental outcome, including intra-uterine fetal death (IUFD), intra-uterine growth retardation (IUGR) and neurological injury. In the LPS model, tumor necrosis factor alpha (TNF-alpha) is the major mediator leading to IUFD, IUGR and neurological injury. In the present study, we investigated the effect of maternally-administered LPS on TNF-alpha in maternal serum, amniotic fluid, fetal liver and fetal brain. The timed pregnant mice were intraperitoneally (i.p.) injected with a single dose of LPS (500microg/kg) on gestational day 17. As expected, TNF-alpha was obviously increased in maternal serum and amniotic fluid in response to LPS. Although maternally-administered LPS also increased the level of TNF-alpha protein in fetal liver and brain, no significant difference in TNF-alpha mRNA level in fetal liver and brain was observed among different groups, suggesting that the increased TNF-alpha protein in fetal liver and brain may be transferred from either the maternal circulation or amniotic fluid or placenta. When the pregnant mice were pretreated with a low-dose LPS (10microg/kg, i.p.) at 4, 12, 24 or 48h before LPS (500microg/kg, i.p.), LPS-evoked TNF-alpha in maternal serum and amniotic fluid was significantly inhibited. Importantly, low-dose LPS pretreatment also greatly attenuated LPS-induced increases in TNF-alpha protein in fetal liver and fetal brain. Taken together, these results indicate that perinatal exposure to low-dose LPS induces a reduced sensitivity to subsequent LPS challenge.

Tumor necrosis factor alpha partially contributes to lipopolysaccharide-induced downregulation of CYP3A in fetal liver: its repression by a low dose LPS pretreatment.

With embryonic development, fetal hepatocytes gradually express various types of cytochromes P450 (CYPs) that play a key role in the detoxification of xenobiotics. In the present study, we showed that maternal lipopolysaccharide (LPS) exposure downregulated cyp3a11 mRNA and CYP3A protein in fetal liver. The increased level of TNF-alpha protein in fetal liver, transferred from either the maternal circulation or amniotic fluid, seems to be associated with LPS-induced downregulation of cyp3a11 mRNA and CYP3A protein in fetal liver. Interestingly, a low dose LPS (10mug/kg) pretreatment attenuated LPS-induced downregulation of cyp3a11 mRNA and CYP3A protein in fetal liver. Correspondingly, a low dose LPS pretreatment attenuated LPS-induced downregulation of pregnane X receptor (pxr) in fetal liver. Additional experiment showed that a low dose LPS pretreatment decreased the level of TNF-alpha in maternal serum and amniotic fluid and counteracted LPS-induced expression of TNF-alpha mRNA in maternal liver and placenta. Although a low dose LPS pretreatment alleviated LPS-induced increase in TNF-alpha in fetal liver, it had little effect on TNF-alpha mRNA in fetal liver. These results suggest that a low dose LPS pretreatment protects fetuses against LPS-induced downregulation of hepatic cyp3a11 and pxr expression through the repression of maternally sourced TNF-alpha production.

[Methylation of H19 gene in ES mice and embryonic stem cells].

To investigate the relationship between the methylation status of imprinted gene H19 and the development of mice derived completely from Embryonic stem cells (ES) by tetraploid embryo complementation. The methylation status of two loci at 5'UTR region in imprinted gene H19 in normal adult control mice, 22 adult ES mice, 8 newborn dead ES mice and embryonic stem (ES) cells with different passage number were detected by using of methylation-sensitive restriction endonuclease-PCR technique. The results indicated that the methylation status of the imprinted gene H19 in adult ES mice were identical to that of adult control mice. However, some significant differences in the methylation status of the imprinted gene H19 were found among newborn dead ES mice, adult ES mice and normal adult control mice. Furthermore, the methylation status of the imprinted gene H19 in ES cells were probably different from that of adult ES mice and normal adult control mice.

[Determination of inorganic elements in rat serum, and vegetable and fruit ferment liquid by ICP-MS].

In the present paper, the contents of thirteen inorganic elements in rat serum, and vegetable and fruit ferment liquid (VFFL) were measured by ICP-MS in order to study the anti-tumor effect of VFFL. Serum or VFFL was digested in nitric and perchloric acids at room temperature and then heated until dryness. The residue was dissolved with 1% (phi) nitric acid prior to ICP-MS analysis. The element contents were quantitated by using 45Sc, 103Rh and 187Re as the internal standards, respectively, according to the rule of close mass number. Certificate references bovine serum (GBW(E)090006) and tea (GBW070605) were employed to validate the proposed method, and the analysis results of most elements in two certificate references were in agreement with their reference values. The intra-day and inter-day precisions of the method in terms of relative standard deviation (RSD) were mainly below 10% and below 15%, respectively. The spiked recoveries for most of studied elements were 80%-110% in rat serum and 90%-120% in VFFL. This method was rapid, highly sensitive, and especially suitable to being applied to small quantity of biological samples with greatly different elements contents. Therefore, we measured the content of thirteen elements in the sera of rats, where in were induced liver cancer by revulsant, and the rate were fed with different dosage of VFFL in intragastric infusion at the same time. It was preliminarily found that the concentrations of some elements in sera of different experiment groups of rats were significantly different, implying the potential anti-tumor effects of VFFL.

Determination of morphine and codeine in urine using poly(dimethylsiloxane) microchip electrophoresis with electrochemical detection.

In this paper, a poly(dimethylsiloxane) (PDMS) microchip with electrochemical (EC) detection was developed for rapid separation and detection of morphine and codeine. It was found that morphine and codeine were well separated within 140 s in phosphate buffer solution (PBS) (pH 6.6, 40 mM)-beta-cyclodextrin (beta-CD) (20 mM)-acetonitrile (30%, v/v). The detection limit was 0.2 microM for morphine and 1 microM for codeine. The protocol was successfully applied to monitoring the amount of morphine and codeine in human urine. Compared with the conventional methods, the presented method had many advantages such as lower instrument cost, less reagent consumption and shorter analysis time.

[DNA methylation and development abnormalities in cloned animals].

Most cloned animals by nuclear transfer were dead before their births, and only a few can develop to their late gestation or adulthood. Although some cloned offsprings can survive, they often have some development disfigurements and abnormal phenotypes in various degrees. DNA methylation is an important modifiable manner of epigenetic dominating the correct expression of gene. It is a main instrument of regulating genome function and plays a prominent part in the embryonic normal development. Through researching the pattern of DNA methylation, we found that there were many abnormal DNA methylation patterns in cloned animals, which might be the primary reasons for inducing premature death of cloned embryos and development abnormalities of cloned animals. This article discusses the function of DNA methylation, the aberrant DNA methylation patterns in cloned animals, and the reasons of inducing abnormal DNA methylation in cloned animals.

[Therapeutic effect of compositive rehabilitation on lumber disc herniation].

OBJECTIVE: To observe the curative effect of different physical rehabilitation techniques on patients with lumbar disc herniation. METHODS: Eighty-four patients were randomly divided into Group A, Group B and Group C. Group A were treated with the computerized pelvis traction and ultrashort wave, Group B were treated with the computerized pelvis traction only, while Groups C were treated with the computerized pelvis traction, the ultrashort wave and the traditional Chinese medicine iontophoresis. The outcome was measured with the Japanese Orthopaedics Association Score (JOA score) about lower back pain (LBP). RESULTS: Compared with before the treatment, the JOA score of all the 3 groups increase markedly after the treatment (P<0.001). Compared with group B, the JOA score of Groups A and Group C significantly increased (P<0.05). Compared with Group A, the JOA score in Group C significantly increased (P<0.05). CONCLUSION: The curative effect of comprehensive rehabilitation on lumbar disc herniation is better than that of the single rehabilitation.

[Influence of Minkeqing oral liquid on IL-6, IL-8, ET-1, TX-B2 in blood and to observe bronchoalveolar lavage fluid of the rat with inhalating ovalbumin].

OBJECTIVE: To observe the effect on infantile allergic cough with Minkeqing oral liquid (Minkeqing) and to study its cell molecular biologic mechanism. METHOD: The rat model was induced by inhalating ovalbumin; then the effects of Minkeqing on IL-6, IL-8, ET-1, TX-B2 in the blood and the bronchoalveolar lavage fluid (BALF) of the animal model were observed. RESULT: Minkeqing could reduce the levels of IL-6,IL-8,ET-1,Tx-B2 in the blood and BALF of the animal model. CONCLUSION: Minkeqing has the significant function of inhibiting the release of inflammatory mediums.

Acupuncture reduced apoptosis and up-regulated BDNF and GDNF expression in hippocampus following hypoxia-ischemia in neonatal rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Acupuncture attenuates neuronal damages following ischemia. AIM OF THE STUDY: The purpose of the present study was to investigate the beneficial effects of acupuncture on hypoxia-ischemia induced brain damages in neonatal rats. MATERIALS AND METHODS: Male postnatal 7 days rats were randomly divided into 3 groups: sham control (sham), hypoxia-ischemia (HI), and HI plus acupuncture treatment (HI+Acu). The rats in HI and HI+Acu groups were submitted to model of neonatal HI, established by occluding the left common carotid artery followed by a 3.5h period of hypoxia (8% O2-92% N2). At 24h after HI, animals were stimulated by acupuncture treatment once a day and the treatment continued during 4 weeks, 5days/week. Behavioral functions, learning and memory ability, and body weight were observed at different time-points after HI. DNA fragmentation assay were performed with TUNEL staining to evaluate apoptosis and expression levels of mitochondrial Bcl-2, mitochondrial Bax, Cleaved caspase 3, Cleaved caspase 9 in the damaged hippocampus were detected by western blotting 28 days following HI. GDNF, BDNF levels in hippocampus were also determined. RESULTS: The results showed that acupuncture significantly promoted growth and development, improved neurobehavioral function, learning and memory ability after 20 days' treatment. Furthermore, we obtained one interesting finding that acupuncture attenuated cellular apoptosis and up-regulated GDNF and BDNF levels in hippocampus. CONCLUSIONS: All of these results suggest that acupuncture as a potential treatment may exert neuroprotective effects via inhibiting cellular apoptosis, increased GDNF and BDNF expression levels in rat hippocampus experiencing HI.

Acemannan accelerates cell proliferation and skin wound healing through AKT/mTOR signaling pathway.

BACKGROUND: Acemannan is a bioactive polysaccharides promoting tissue repair. However, the roles of acemannan in skin wound healing and the underlying molecular mechanisms are largely unclear. OBJECTIVE: The goal of this study is to investigate the positive role of acemannan in cutaneous wound healing and its mechanism. METHODS: Mouse skin wound model and skin primary fibroblasts were used to demonstrate the positive effect of acemannan on cutaneous wound healing. The expressions of cell proliferation nuclear antigen ki-67, cyclin D1 and activity of AKT/mTOR signaling were analyzed in acemannan-treated fibroblasts and mice. Rapamycin and AKT inhibitor VIII were used to determine the key role of AKT/mTOR signaling in acemannan-promoting cutaneous wound healing. RESULTS: We found that acemannan significantly accelerated skin wound closure and cell proliferation. Acemannan promoted the expression of cyclin D1 in cultured fibroblasts, which was mediated by AKT/mTOR signal pathway leading to enhanced activity of the eukaryotic translation initiation factor-4F (eIF4F) and increased translation of cyclin D1. In contrast, pharmaceutical blockade of AKT/mTOR signaling by mTOR inhibitor rapamycin or AKT inhibitor VIII abolished acemannan-induced cyclin D1 translation and cell proliferation. In vivo studies confirmed that the activation of AKT/mTOR by acemannan played a key role in wound healing, which could be reversed by rapamycin. CONCLUSION: Acemannan promoted skin wound healing partly through activating AKT/mTOR-mediated protein translation mechanism, which may represent an alternative therapy approach for cutaneous wound.

Enhanced Neuroprotective Effects of Coadministration of Tetrandrine with Glutathione in Preclinical Model of Parkinson's Disease.

Aim. In this study we examined the influence of tetrandrine (Tet) on the neuroprotective effects of glutathione (GSH) in the 6-hydroxydopamine- (6-OHDA-) lesioned rat model of Parkinson's disease (PD). Methods. Levels in the redox system, dopamine (DA) metabolism, dopaminergic neuronal survival, and apoptosis of the substantia nigra (SN) and striatum, as well as the rotational behavior of animals were examined after a 50-day administration of GSH + Tet (or GSH) and/or L-3,4-dihydroxyphenylalanine (L-dopa) to PD rats. Ethics Committee of Huashan Hospital, Fudan University approved the protocol (number SYXK2009-0082). Results. Administration of GSH or Tet alone did not show any significant effects on the factors evaluated in the PD rats. However, in the GSH + Tet group, we observed markedly decreased oxidative damage, inhibition of DA metabolism and enhanced DA synthesis, increased tyrosine hydroxylase- (TH-) immunopositive neuronal survival, and delayed apoptosis of dopaminergic neurons in the SN. Animal rotational behavior was improved in the GSH + Tet group. Additionally, coadministration of GSH + Tet appeared to offset the possible oxidative neurotoxicity induced by L-dopa. Conclusion. In this study, we demonstrated that tetrandrine allowed occurrence of the neuroprotective effect of glutathione probably due to inhibition of P-glycoprotein on 6-hydroxydopamine-lesioned rat models of Parkinson's disease, including rats undergoing long-term L-dopa treatment.

SUMO-2 promotes mRNA translation by enhancing interaction between eIF4E and eIF4G.

Small ubiquitin-like modifier (SUMO) proteins regulate many important eukaryotic cellular processes through reversible covalent conjugation to target proteins. In addition to its many well-known biological consequences, like subcellular translocation of protein, subnuclear structure formation, and modulation of transcriptional activity, we show here that SUMO-2 also plays a role in mRNA translation. SUMO-2 promoted formation of the active eukaryotic initiation factor 4F (eIF4F) complex by enhancing interaction between Eukaryotic Initiation Factor 4E (eIF4E) and Eukaryotic Initiation Factor 4G (eIF4G), and induced translation of a subset of proteins, such as cyclinD1 and c-myc, which essential for cell proliferation and apoptosis. As expected, overexpression of SUMO-2 can partially cancel out the disrupting effect of 4EGI-1, a small molecule inhibitor of eIF4E/eIF4G interaction, on formation of the eIF4F complex, translation of the cap-dependent protein, cell proliferation and apoptosis. On the other hand, SUMO-2 knockdown via shRNA partially impaired cap-dependent translation and cell proliferation and promoted apoptosis. These results collectively suggest that SUMO-2 conjugation plays a crucial regulatory role in protein synthesis. Thus, this report might contribute to the basic understanding of mammalian protein translation and sheds some new light on the role of SUMO in this process.