The immune regulation and therapeutic potential of the SMAD gene family in breast cancer

Breast cancer is a serious threat to human health. The transforming growth factor-β signaling pathway is an important pathway involved in the occurrence and development of cancer. The SMAD family genes are responsible for the TGF-β signaling pathway. However, the mechanism by which genes of the SMAD family are involved in breast cancer is still unclear. Therefore, it is necessary to investigate the biological roles of the SMAD family genes in breast cancer. We downloaded the gene expression data, gene mutation data, and clinical pathological data of breast cancer patients from the UCSC Xena database. We used the Wilcox test to estimate the expression of genes of the SMAD family in cancers. And the biological functions of SMAD family genes using the DAVID website. The Pearson correlation method was used to explore the immune cell infiltration and drug response of SMAD family genes. We conducted in biological experiments vitro and vivo. In this study, we integrated the multi-omics data from TCGA breast cancer patients for analysis. The expression of genes of SMAD family was significantly dysregulated in patients with breast cancer. Except for SMAD6, the expression of other SMAD family genes was positively correlated. We also found that genes of the SMAD family were significantly enriched in the TGF-β signaling pathway, Hippo signaling pathway, cell cycle, and cancer-related pathways. In addition, SMAD3, SMAD6, and SMAD7 were lowly expressed in stage II breast cancer, while SMAD4 and SMAD2 were lowly expressed in stage III cancer. Furthermore, the expression of genes of the SMAD family was significantly correlated with immune cell infiltration scores. Constructing a xenograft tumor mouse model, we found that SMAD3 knockdown significantly inhibited tumorigenesis. Finally, we analyzed the association between these genes and the IC50 value of drugs. Interestingly, patients with high expression of SMAD3 exhibited significant resistance to dasatinib and staurosporine, while high sensitivity to tamoxifen and auranofin. In addition, SMAD3 knockdown promoted the apoptosis of BT-549 cells and decreased cell activity, and BAY-1161909 and XK-469 increased drug efficacy. In conclusion, genes of the SMAD family play a crucial role in the development of breast cancer.

The translocon protein FtsHi1 is an ATP-dependent DNA/RNA helicase that prevents R-loop accumulation in chloroplasts

R-loops, three-stranded nucleic acid structures consisting of a DNA: RNA hybrid and displaced single-stranded DNA, play critical roles in gene expression and genome stability. How R-loop homeostasis is integrated into chloroplast gene expression remains largely unknown. We found an unexpected function of FtsHi1, an inner envelope membrane-bound AAA-ATPase in chloroplast R-loop homeostasis of Arabidopsis thaliana. Previously, this protein was shown to function as a component of the import motor complex for nuclear-encoded chloroplast proteins. However, this study provides evidence that FtsHi1 is an ATP-dependent helicase that efficiently unwinds both DNA-DNA and DNA-RNA duplexes, thereby preventing R-loop accumulation. Over-accumulation of R-loops could impair chloroplast transcription but not necessarily genome integrity. The dual function of FtsHi1 in both protein import and chloroplast gene expression may be important to coordinate the biogenesis of nuclear- and chloroplast-encoded subunits of multi-protein photosynthetic complexes. This study suggests a mechanical link between protein import and R-loop homeostasis in chloroplasts of higher plants.

[Pathological evaluation of endoscopic submucosal dissection for early gastric cancer and precancerous lesion in 411 cases]

OBJECTIVE

To evaluate the pathological characteristics of endoscopic submucosal dissection (ESD) specimens for early gastric cancer and precancerous lesions, accumulating experience for clinical management and pathological analysis.

METHODS

A total of 411 cases of early gastric cancer or precancerous lesions underwent ESD. According to the Japanese guidelines for ESD treatment of early gastric cancer and classification of gastric carcinoma, the clinicopathological data, pathologic evaluation, concordance rate of pathological diagnosis between preoperative endoscopic forceps biopsies and their ESD specimens (in 400 cases), as well as the risk factors of non-curative resection of early gastric cancer, were analyzed retrospectively.

RESULTS

23.4% (96/411) of the 411 cases were adenoma/low-grade dysplasia and 76.6% (315/411) were early gastric cancer. The latter included 28.0% (115/411) non-invasive carcinoma/high-grade dysplasia and 48.7% (200/411) invasive carcinoma. The concordance rate of pathological diagnosis between endoscopic forceps biopsies and ESD specimens was 66.0% (264/400), correlating with pathological diagnosis and lesion location (P < 0.01). The rate of upgraded diagnosis and downgraded diagnosis after ESD was 29.8% (119/400) and 4.2% (17/400), respectively. Among the 315 cases of early gastric cancer, there were 277 cases (87.9%) of differentiated type and 38 cases (12.1%) of undifferentiated type. In the study, 262 cases (83.2%) met with absolute indication, while 53 cases (16.8%) met relative indication. En bloc and curative resection rates were 98.1% and 82.9%, respectively. Risk factors for non-curative resection included a long diameter >20 mm (OR=3.631, 95%CI: 1.170-11.270, P=0.026), tumor infiltration into submucosa (OR=69.761, 95%CI: 21.033-231.376, P < 0.001)and undifferentiated tumor histology (OR=16.950, 95%CI: 4.585-62.664, P < 0.001).

CONCLUSION

Several subjective and objective factors, such as the limitations of biopsy samples, the characteristics and distribution of the lesions, different pathological understanding, and the endoscopic sampling and observation, can lead to the differences between the preoperative and postoperative pathological diagnosis of ESD. In particular, the pathological upgrade of postoperative diagnosis was more significant and should receive more attention by endoscopists and pathologists. The curative resection rate of early gastric cancer in ESD was high. Non-curative resection was related to the long diameter, the depth of tumor invasion and histological classification. ESD can also be performed in undifferentiated early gastric cancer if meeting the indication criteria. The comprehensive and standardized pathological analysis of ESD specimens is clinically important to evaluate the curative effect of ESD operation and patient outcomes.

P-583 PCOS patients got better IVF/ICSI outcomes with “higher” progesterone level on hCG day: a retrospective study of Ten years data

Study question

We aimed to investigate whether serum Progesterone (P) on the day of hCG trigger can be used as a biomarker to predict the IVF/ICSI outcomes in PCOS patients.

Summary answer

PCOS patients got better IVF/ICSI outcomes with “higher” progesterone level (2.7-5.9mmol/L).

What is known already

There were several studies suggesting serum Progesterone (P) on the day of hCG trigger can be used as a biomarker to predict IVF outcomes, and to decide fresh cycle embryo transfer or frozen all. But there was few study focus on PCOS patients.

Study design, size, duration

This is a single-center retrospective cohort study in PCOS women undergoing the first transfer of an IVF cycle between January 1st 2010 and December 31th 2019. There were 141,539 oocyte retrieval cycles during the study period, and 97,189 cycles were their first IVF cycle. PCOS was diagnosed according to the Rotterdam criteria. Among them, 3,146 cycles full filled the inclusion and exclusion criteria, and all with two embryos transferred on Day 3.

Participants/materials, setting, methods

We compared the live birth rate of fresh embryo transfer, stratified for serum P level. We looked for interaction between serum P level and live birth rate of fresh cycles. The serum P level within normal range (&lt; 6nmol/L) on the day of hCG trigger day was divided into 4 quartiles. The four quartiles were defined as ≤ 1.35 nmol/L (Q1), &gt;1.35-1.93 nmol/L (Q2), &gt;1.93-2.7 nmol/L (Q3), &gt;2.7 nmol/L (Q4).

Main results and the role of chance

The baseline characteristics with no different between groups, except BMI. The patients in Q4 group with lowest BMI, significantly higher number of oocytes retrieved and live birth rate (P &lt; 0.05) . The Logistic regression analysis of the relative factors on live birth rate including BMI, basal LH and number of oocytes retrieved [P = 0.003, 0.030, 0.037 respectively, 95%CI (1.022, 1.111), (1.004, 1.076), (1.002, 1.082)].

Limitations, reasons for caution

Due to the retrospective nature of this study, a well-designed and matched large sample prospective study is needed. The definition of elevated P level and the method of hormonal assessments were different between studies, this limiting the comprehensive analysis of researches and the further verification of existing results.

Wider implications of the findings

PCOS patients who with normal range P level on hCG day, got better IVF/ICSI outcomes with “higher” progesterone level (2.7-5.9mmol/L). Weight control is important for PCOS patients accepting IVF treatment.

Trial registration number

NOT APPLICABLE

Functional redox links between lumen thiol oxidoreductase1 and serine/threonine-protein kinase STN7

In response to changing light quantity and quality, photosynthetic organisms perform state transitions, a process which optimizes photosynthetic yield and mitigates photo-damage. The serine/threonine-protein kinase STN7 phosphorylates the light-harvesting complex of photosystem II (PSII; light-harvesting complex II), which then migrates from PSII to photosystem I (PSI), thereby rebalancing the light excitation energy between the photosystems and restoring the redox poise of the photosynthetic electron transport chain. Two conserved cysteines forming intra- or intermolecular disulfide bonds in the lumenal domain (LD) of STN7 are essential for the kinase activity although it is still unknown how activation of the kinase is regulated. In this study, we show lumen thiol oxidoreductase 1 (LTO1) is co-expressed with STN7 in Arabidopsis (Arabidopsis thaliana) and interacts with the LD of STN7 in vitro and in vivo. LTO1 contains thioredoxin (TRX)-like and vitamin K epoxide reductase domains which are related to the disulfide-bond formation system in bacteria. We further show that the TRX-like domain of LTO1 is able to oxidize the conserved lumenal cysteines of STN7 in vitro. In addition, loss of LTO1 affects the kinase activity of STN7 in Arabidopsis. Based on these results, we propose that LTO1 helps to maintain STN7 in an oxidized active state in state 2 through redox interactions between the lumenal cysteines of STN7 and LTO1.

[Analysis of the self-conscious health status and influencing factors of greenhouse agricultural workers in Beijing suburb]

Objective: To explore the self-conscious health status and related influencing factors of greenhouse agricultural workers in Beijing suburb, so as to provide scientific basis for developing strategies to improve and promote the occupational health conditions of those workers. Methods: According to the production characteristics and scale of the main agricultural districts or counties in the suburb of Beijing, 182 agricultural production personnel were randomly selected to investigate the general situation, occupational situation and self-conscious health status during June 2018 to December 2019. The relevant factors which may affect the self-conscious health conditions were also analyzed by statistical methods. Results: The detection or reported rate of self-conscious health problems was 51.6% (94/182) , among which 29.1% (53/182) workers reported musculoskeletal disorder diseases and 21.4% (39/182) workers reported nervous system diseases. And the self-conscious health status of greenhouse agricultural workers were statistically different in household registration, gender, marital status, working years, mixing or spraying pesticides, smoking or eating in the greenhouse (P<0.05) . Moreover, gender, mixing or spraying pesticide, eating and smoking behavior in the workplace all had an impact on the risk of self-conscious health status of greenhouse agricultural workers (P< 0.05) . Specifically, male is the protective factor to reduce the occurrence of self-conscious symptoms of greenhouse agricultural workers (OR=0.447, 95%CI: 0.234~0.852) , while mixing or spraying pesticides and smoking or eating behaviors in the workplace are the risk factors (OR=1.055, 2.524; 95%CI: 0.503~2.210, 1.107~5.755) . Conclusion: Reducing pesticide use from the source thus minimize related exposure opportunities, strengthening occupational health education thus foster good hygienic habits and improve individual protection consciousness are of great significance for the health protection of greenhouse agricultural workers in Beijing suburb.

Endothelin-1 induces chondrocyte senescence and cartilage damage via endothelin receptor type B in a post-traumatic osteoarthritis mouse model

OBJECTIVES

This study aimed to investigate the role of endothelin-1 (ET-1), originally known as the potent vasoconstrictor, and its receptors in chondrocyte senescence and osteoarthritis (OA) development.

METHOD

Temporal changes of ET-1 and its receptors with OA development were characterized in a posttraumatic OA (PTOA) mouse model at time zero, 1-month and 4-month after surgical induction via destabilization of medial meniscus (DMM). A transgenic ET-1 overexpression (TET-1) mouse model was deployed to assess the impact of upregulated ET-1 on chondrocyte senescence and cartilage degradation. Effects of endothelin receptor blockade on chondrocyte senescence and OA development were further examined both in vitro and in vivo.

RESULTS

Local expression of ET-1 in subchondral bone and synovium upregulated after DMM with an increase of plasma ET-1 level from 3.18 ± 0.21 pg/ml at time zero to 6.47 ± 0.34 pg/ml at 4-month post-surgery. Meanwhile, endothelin type B receptor (ET_BR) (53.31 ± 2.42% to 83.8 ± 2.65%) and p16^INK4a (10.91 ± 1.07% to 28.2 ± 1.0%) positve chondrocytes accumulated in articular cartilage since 1-month prior to cartilage loss at 4-month post-surgery. Overexpressed ET-1 promoted p16^INK4a-positive senescent chondrocytes accumulation and cartilage degradation in TET-1 mice. Selective blockade of ET_BR, but not ET_AR, lowered the expression of p16^INK4a in ET-1 or H₂O₂-induced chondrocyte senescence model, and mitigated the severity of murine PTOA. Intriguingly, reactive oxygen species (ROS) scavenger, Vitamin C, could rescue ET-1-induced chondrocyte senescence in vitro associated with restoration of mitochondrial dynamics.

CONCLUSION

ET-1 could induce chondrocytes senescence and cartilage damages via ET_BR in PTOA.

Liquid-Liquid Phase Transition Drives Intra-chloroplast Cargo Sorting

In eukaryotic cells, organelle biogenesis is pivotal for cellular function and cell survival. Chloroplasts are unique organelles with a complex internal membrane network. The mechanisms of the migration of imported nuclear-encoded chloroplast proteins across the crowded stroma to thylakoid membranes are less understood. Here, we identified two Arabidopsis ankyrin-repeat proteins, STT1 and STT2, that specifically mediate sorting of chloroplast twin arginine translocation (cpTat) pathway proteins to thylakoid membranes. STT1 and STT2 form a unique hetero-dimer through interaction of their C-terminal ankyrin domains. Binding of cpTat substrate by N-terminal intrinsically disordered regions of STT complex induces liquid-liquid phase separation. The multivalent nature of STT oligomer is critical for phase separation. STT-Hcf106 interactions reverse phase separation and facilitate cargo targeting and translocation across thylakoid membranes. Thus, the formation of phase-separated droplets emerges as a novel mechanism of intra-chloroplast cargo sorting. Our findings highlight a conserved mechanism of phase separation in regulating organelle biogenesis.

[Clinical short-term and long-term efficacy of endoscopic submucosal dissection in the treatment of early low rectal cancer and precancerous lesions]

Objective: To evaluate the short-term and long-term efficacy of endoscopic submucosal dissection (ESD) in the treatment of early low rectal cancer and precancerous lesions. Methods: Inclusion criteria: (1) Distance from the lower margin of tumor to the anal was ≤ 5 cm. (2) Early low rectal cancers were any size rectal epithelial tumors with infiltration depth limited to the mucosa and submucosa, which were diagnosed by postoperative pathology as high-grade intraepithelial neoplasia or adenocarcinoma of the rectum with infiltration depth of intramucosal or submucosal cancer (M or SM stage). (3) Precancerous lesions included adenoma and low-grade intraepithelial neoplasia of the rectum. (4) Patients received ESD treatment. Patients with tumor invasion depth over submucosa by pathology were excluded. From January 2008 to January 2018, 63 patients meeting the above criteria in Peking University First Hospital were enrolled in this descriptive cohort study. The disease characteristics, clinical manifestations, pathological types, treatment time, hospitalization time, en bloc resection rate (resection of the whole lesion), complete resection rate (both the horizontal and vertical incision margins were negative), postoperative complications and follow-up results were analyzed. Cummulative survival rate was calculated by Kaplan-Meier. Results: The diameter of the lesion was (29.0±23.4) mm and the distance from the lesion to the anus was (2.7±1.8) cm. The median operation time was 45.0 (range, 10.0 to 360.0) minutes, the median hospitalization time was 3.0 (range, 2.0 to 12.0) days, en bloc resection rate was 100%, complete resection rate was 96.8% (61/63), and 1 case (1.6%) had postoperative bleeding. The follow-up rate was 87.3% (55/63) and the median follow-up time was 57.9 (range, 15.6 to 121.1) months. No local recurrence was found during the follow-up period and the 5-year survival rate was 100%. Conclusion: Short- and long-term efficacy of ESD are quite good in the treatment of patients with early low rectal cancer and precancerous lesions.

ECD1 functions as an RNA-editing trans-factor of rps14-149 in plastids and is required for early chloroplast development in seedlings

Chloroplast development is a highly complex process and the regulatory mechanisms have not yet been fully characterized. In this study, we identified Early Chloroplast Development 1 (ECD1), a chloroplast-localized pentatricopeptide repeat protein (PPR) belonging to the PLS subfamily. Inactivation of ECD1 in Arabidopsis led to embryo lethality, and abnormal embryogenesis occurred in ecd1/+ heterozygous plants. A decrease in ECD1 expression induced by RNAi resulted in seedlings with albino cotyledons but normal true leaves. The aberrant morphology and under-developed thylakoid membrane system in cotyledons of RNAi seedlings suggests a role of ECD1 specifically in chloroplast development in seedlings. In cotyledons of ECD1-RNAi plants, RNA-editing of rps14-149 (encoding ribosomal protein S14) was seriously impaired. In addition, dramatically decreased plastid-encoded RNA polymerase-dependent gene expression and abnormal chloroplast rRNA processing were also observed. Taken together, our results indicate that ECD1 is indispensable for chloroplast development at the seedling stage in Arabidopsis.

Protease sensitivity and redistribution of CD71 and glycophorin A on K562 cells

Transmembrane proteins are delivered to plasma membrane from the endoplasmic reticulum and Golgi complex by vesicular transport along with the cytoskeletal network. Disruption of this process likely affects transmembrane protein expression. K562 cells were digested with Streptomyces griseus protease for different periods of time, and then re-cultured with different cytoskeletal and glycosylation inhibitors. Cell viability and surface expression of transferrin receptor (CD71) and glycophorin A (GPA) were analyzed before and after re-culture by flow cytometry. We found that digestion with protease almost completely removed extracellular CD71 and GPA but their expression recovered to the initial levels after re-culture for 8 h and 24 h, respectively. The microtubule depolymerizer colchicine promoted cell surface recovery of CD71 but inhibited that of GPA; the microtubule stabilizer paclitaxel inhibited cell surface recovery of CD71 but promoted that of GPA; the microfilament depolymerizer cytochalasin D had no effect on cell surface recovery of CD71 and GPA; the microfilament stabilizer phalloidin inhibited cell surface recovery of GPA. The glycosylation inhibitor tunicamycin inhibited the recovery of both CD71 and GPA, and BADGP inhibited the recovery of GPA. These studies show differential sensitivities of surface proteins on K562 cells to proteases, and suggest molecular mechanisms of transmembrane protein transport and cycling.

Answers to if the Lead Aprons are Really Helpful in Nuclear Medicine from the Perspective of Spectroscopy

Wearing lead X-ray-protective aprons is a routine in nuclear medicine department in parts of China. However, the staff are often perplexed by questions such as if it is imperative to wear aprons when injecting radioactive drugs, how much radiation dosage can be shielded and if the apron will produce secondary radiation instead? To answer these questions, a semiconductor detector was employed to record different gamma and X-ray spectra with and without the lead apron or lead sheet. Then, we could estimate the signal shielding ratio to different photons for the lead apron and compare with the hospitals measured data. In general, the two results coincided well. The spectral results showed that the detrimental secondary X-rays irradiation rises when the energy of gamma rays exceeds the K absorption edge of lead (88 keV). Moreover, the aprons are not so effective for gamma rays of 364 keV emitted from 131I and 511 keV emitted from the positron radioactive nuclides. This work is purely a physical measurement in the laboratory. To the best of our knowledge, this is the first quantitative study on the level of gamma rays protection offered by the medical lead aprons and the importance of the spectroscopic measurements is discussed in this paper.

Sirt 1 activator attenuates the bleomycin-induced lung fibrosis in mice via inhibiting epithelial-to-mesenchymal transition (EMT)

OBJECTIVE

The aim of this study was to investigate the effect of resveratrol on the idiopathic bleomycin (BLM)-induced pulmonary fibrosis, which is increasingly recognized as an epithelial-to-mesenchymal transition (EMT)-associated disease.

MATERIALS AND METHODS

We evaluated the effect of resveratrol on the BLM-induced fibrosis in a mouse model, via monitoring the pathological chance in mice lung, the mice body weight change and the mice death. And we also explored the regulation by BLM on (and) resveratrol on the expression and activity of Sirt 1 and on the expression of epithelial-to-mesenchymal transition (EMT)-associated markers in mice lung.

RESULTS

It was demonstrated that resveratrol ameliorated the BLM-induced fibrosis-like pathological change in mice lung, inhibited BLM-induced mice body weight loss and death. Moreover, resveratrol also inhibited the BLM-induced EMT-associated molecular events, such as reduced E-cadherin and elevated Collagen I and α-SMA. We also confirmed the amelioration by resveratrol on the BLM-mediated inhibition of Sirt 1 in expression and activity in mice lung.

CONCLUSIONS

Our study confirmed the inhibitory role of resveratrol in the BLM-induced pulmonary fibrosis in a mouse model. Resveratrol ameliorated the BLM-induced pathological change of fibrosis, mice body weight loss and death. And such amelioration might be associated with the activation of Sirt 1 in mice lung. The present study implied that resveratrol might be a promising agent for effective control the pulmonary fibrosis.

Characterization and molecular mapping of stripe rust resistance gene Yr61 in winter wheat cultivar Pindong 34

We report a new stripe rust resistance gene on chromosome 7AS in wheat and molecular markers useful for transferring it to other wheat genotypes. Several new races of the stripe rust pathogen have established throughout the wheat growing regions of China in recent years. These new races are virulent to most of the designated seedling resistance genes limiting the resistance sources. It is necessary to identify new genes for diversification and for pyramiding different resistance genes in order to achieve more durable resistance. We report here the identification of a new resistance gene, designated as Yr61, in Chinese wheat cultivar Pindong 34. A mapping population of 208 F2 plants and 128 derived F2:3 lines in a cross between Mingxian 169 and Pindong 34 was evaluated for seedling stripe rust response. A genetic map consisting of eight resistance gene analog polymorphism (RGAP), two sequence-tagged site (STS) and four simple sequence repeat (SSR) markers was constructed. Yr61 was located on the short arm of chromosome 7A and flanked by RGAP markers Xwgp5467 and Xwgp5765 about 1.9 and 3.9 cM in distance, which were successfully converted into STS markers STS5467 and STS5765b, respectively. The flanking STS markers could be used for marker-assisted selection of Yr61 in breeding programs.

Translational control of the activation of transcription factor NF-κB and production of type I interferon by phosphorylation of the translation factor eIF4E

Type I interferon is an integral component of the antiviral response, and its production is tightly controlled at the levels of transcription and translation. The eukaryotic translation-initiation factor eIF4E is a rate-limiting factor whose activity is regulated by phosphorylation of Ser209. Here we found that mice and fibroblasts in which eIF4E cannot be phosphorylated were less susceptible to virus infection. More production of type I interferon, resulting from less translation of Nfkbia mRNA (which encodes the inhibitor IκBα), largely explained this phenotype. The lower abundance of IκBα resulted in enhanced activity of the transcription factor NF-κB, which promoted the production of interferon-β (IFN-β). Thus, regulated phosphorylation of eIF4E has a key role in antiviral host defense by selectively controlling the translation of an mRNA that encodes a critical suppressor of the innate antiviral response.

p53-dependent translational control of senescence and transformation via 4E-BPs

eIF4E, the mRNA 5' cap-binding translation initiation factor, is overexpressed in numerous cancers and is implicated in mechanisms underlying oncogenesis and senescence. 4E-BPs (eIF4E-binding proteins) inhibit eIF4E activity, and thereby act as suppressors of eIF4E-dependent pathways. Here, we show that tumorigenesis is increased in p53 knockout mice that lack 4E-BP1 and 4E-BP2. However, primary fibroblasts lacking 4E-BPs, but expressing p53, undergo premature senescence and resist oncogene-driven transformation. Thus, the p53 status governs 4E-BP-dependent senescence and transformation. Intriguingly, the 4E-BPs engage in senescence via translational control of the p53-stabilizing protein, Gas2. Our data demonstrate a role for 4E-BPs in senescence and tumorigenesis and highlight a p53-mediated mechanism of senescence through a 4E-BP-dependent pathway.

Insulin-like growth factor II mRNA binding protein 1 modulates Rev-dependent human immunodeficiency virus type 1 RNA expression

Human immunodeficiency virus type 1 (HIV-1) needs to overcome cellular counter mechanisms such as to successfully propagate itself. Results of our recent studies show that overexpression of insulin-like growth factor II mRNA binding protein 1 (IMP1) inhibits production of infectious HIV-1 particles through adversely affecting virus maturation. Here, we report that IMP1 interacts with HIV-1 Rev protein and its ectopic expression causes relocation of Rev from the nucleus to the cytoplasm. In accordance with this observation, ectopic expression of IMP1 severely diminishes Rev-dependent expression of CAT enzyme and disturbs HIV-1 RNA expression by causing accumulation of the multiple spliced viral RNA. Results of mutagenesis analysis further reveal that the KH4 domain represents the key element of IMP1 in modulating HIV-1 RNA expression. Taken together, these data suggest, in addition to hampering virus assembly, that IMP1 also has an effect on Rev-dependent viral RNA expression.

Fragile X mental retardation protein restricts replication of human immunodeficiency virus type 1

Gag protein is the major structural component of human immunodeficiency virus type 1 (HIV-1) particles and drives virus assembly on cellular membranes. This function of Gag is attributed to its intrinsic self-multimerization ability as well as its interaction with cellular factors such as TSG101 that binds to the PTAP sequence in the p6 region of Gag and promotes HIV-1 budding through recruiting the ESCRT (endosomal sorting complex required for transport). As a result of its essential role in virus assembly, Gag also becomes the target of cellular restriction factors such as APOBEC3G and Trim5alpha. In this study, we report that the fragile X mental retardation protein (FMRP) interacts with HIV-1 Gag and is packaged into virus particles. Although knockdown of FMRP does not markedly affect production of virus particles, infectivity of HIV-1 virions was significantly decreased. Consistent with this observation, overexpression of the wild type FMRP, but not the FMRP mutants that lack the KH1 or the KH2 domains, led to 2- to 3-fold reduction of virus infectivity. Together, these results suggest that FMRP diminishes HIV-1 infectivity through association with viral Gag protein and virus particles.

Control of eIF4E cellular localization by eIF4E-binding proteins, 4E-BPs

Eukaryotic initiation factor (eIF) 4E, the mRNA 5'-cap-binding protein, mediates the association of eIF4F with the mRNA 5'-cap structure to stimulate cap-dependent translation initiation in the cytoplasm. The assembly of eIF4E into the eIF4F complex is negatively regulated through a family of repressor proteins, called the eIF4E-binding proteins (4E-BPs). eIF4E is also present in the nucleus, where it is thought to stimulate nuclear-cytoplasmic transport of certain mRNAs. eIF4E is transported to the nucleus via its interaction with 4E-T (4E-transporter), but it is unclear how it is retained in the nucleus. Here we show that a sizable fraction (approximately 30%) of 4E-BP1 is localized to the nucleus, where it binds eIF4E. In mouse embryo fibroblasts (MEFs) subjected to serum starvation and/or rapamycin treatment, nuclear 4E-BPs sequester eIF4E in the nucleus. A dramatic loss of nuclear 4E-BP1 occurs in c-Ha-Ras-expressing MEFs, which fail to show starvation-induced nuclear accumulation of eIF4E. Therefore, 4E-BP1 is a regulator of eIF4E cellular localization.

The requirement of the DEAD-box protein DDX24 for the packaging of human immunodeficiency virus type 1 RNA

RNA helicases play important roles in RNA metabolism. Human immunodeficiency virus type 1 (HIV-1) does not carry its own RNA helicase, the virus thus needs to exploit cellular RNA helicases to promote the replication of its RNA at various steps such as transcription, folding and transport. In this study, we report that knockdown of a DEAD-box protein named DDX24 inhibits the packaging of HIV-1 RNA and thus diminishes viral infectivity. The decreased viral RNA packaging as a result of DDX24-knockdown is observed only in the context of the Rev/RRE (Rev response element)-dependent but not the CTE (constitutive transport element)-mediated nuclear export of viral RNA, which is explained by the specific interaction of DDX24 with the Rev protein. We propose that DDX24 acts at the early phase of HIV-1 RNA metabolism prior to nuclear export and the consequence of this action extends to the viral RNA packaging stage during virus assembly.

The packaging of human immunodeficiency virus type 1 RNA is restricted by overexpression of an RNA helicase DHX30

RNA helicases are a large family of proteins that are able to unwind RNA duplex and remodel the structure of RNA-protein (RNP) complexes using energy derived from hydrolysis of nucleotide triphosphates (NTPs). Every step of cellular RNA metabolism involves the activity of RNA helicases. Not surprisingly, more and more RNA helicases are reported to participate in the replication of viruses including the human immunodeficiency virus type 1 (HIV-1). Here, we provide evidence that overexpression of an RNA helicase named DHX30 enhances HIV-1 gene expression, but leads to the generation of viruses that package significantly low levels of viral RNA and exhibit severely decreased infectivity. These data reveal the complex roles of DHX30 in HIV-1 replication and implicate an inhibitory activity of DHX30 in HIV-1 RNA packaging.

Immunotherapy, phase I study of immunotherapy with carcinoembryonic antigen peptide -pulsed, autologous human cultured dendritic cells in patients with advanced non-small cell lung cancer

12517

Background: To study toxicity tolerance and dose-effect relationship of carcinoembryuonic antigen peptide-pulsed dendritic cells in patients with advanced lung cancer. Methods: cells preparations enriched for autologous DCs were generated from the patients plastic adherent peripheral blood mononuclear cells in media supplemented with granulocyte macrophage colony -stimulating factor and interleukin-4. 37C0, 5%CO2 culture for 7–10. The DCs were loaded with carcinoembryonic antigen(CEA) in day 7, Groups of three to six patients received four weekly or biweekly i.v. infusions of the CAP-1-loaded DC in escalating dose levels of 1 × 106, 1 × 107, and 1 × 108 cells/dose. Patients with lung cancer received iv injections DCs. There were no toxicities directly referable to the treatments. Results: Total 22 patients with lung cancer received DCs immunotherapy. DCs infusion were 2.5×106-9.6×107,means 15.03×106. The early clinical trials suggest that vaccination with CEA vaccines is safe, producing few side-effects, and can lead to CEA-specific immunity. Conclusions: We conclude that it is feasible and safe to generate and administer large numbers of DCs loaded with CEA peptide to patients with lung cancer.

No significant financial relationships to disclose.

eIF4E--from translation to transformation

Over the years, studies have focused on the transcriptional regulation of oncogenesis. More recently, a growing emphasis has been placed on translational control. The Ras and Akt signal transduction pathways play a critical role in regulating mRNA translation and cellular transformation. The question arises: How might the Ras and Akt signaling pathways affect translation and mediate transformation? These pathways converge on a crucial effector of translation, the initiation factor eIF4E, which binds the 5'cap of mRNAs. This review focuses on the role of eIF4E in oncogenesis. eIF4E controls the translation of various malignancy-associated mRNAs which are involved in polyamine synthesis, cell cycle progression, activation of proto-oncogenes, angiogenesis, autocrine growth stimulation, cell survival, invasion and communication with the extracellular environment. eIF4E-mediated translational modulation of these mRNAs plays a pivotal role in both tumor formation and metastasis. Interestingly, eIF4E activity is implicated in mitosis, embryogenesis and in apoptosis. Finally, the finding that eIF4E is overexpressed in several human cancers makes it a prime target for anticancer therapies.

Protein crystallization by using porous glass substrate

The effects of a commercially available porous glass substrate (Corning Porous Glass No.7930) on the heterogeneous nucleation of proteins [hen egg-white lysozyme (HEWL), thaumatin and apoferritin] have been investigated in order to develop an improved method to facilitate the nucleation of protein crystals. It was found that the porous glass substrate could promote the nucleation at lower supersaturations. The induction time for nucleation decreased, and the crystals obtained from porous glass substrates were larger than those from normal glass substrates. Many pores and channels of 10-100 nm in diameter were observed on the porous glass surface by atomic force microscopy (AFM). It is believed that these pores and channels are crucial for facilitating the nucleation process in this work.

Deletion of stem-loop 3 is compensated by second-site mutations within the Gag protein of human immunodeficiency virus type 1

Encapsidation of human immunodeficiency virus type 1 (HIV-1) RNA involves specific interactions between viral Gag proteins and viral RNA elements located at the 5' untranslated region (UTR). These RNA elements are termed packaging (psi) or encapsidation (E) signals and mainly comprise the stem-loop 1 (SL1) and SL3 RNA structures. We have previously shown that deletion of the SL1 sequences is compensated by second-site mutations within Gag. Similar studies are now extended to SL3 and the results demonstrate that deletion of this RNA structure is rescued by two point mutations, i.e., A11V in p2 and I12V in nucleocapsid (NC). These two compensatory mutations are different from those associated with the rescue of SL1 deletion, suggesting that SL1 and SL3 may bind to different residues of Gag during viral RNA packaging. Analysis of virion-derived RNA in native agarose gels shows that deletion of SL3 leads to decreases in both viral RNA packaging and dimerization. These defects are corrected by the compensatory mutations A11V and I12V. Yet, defects in viral RNA dimerization at an early stage that were caused by the SL3 deletion in the context of a viral protease-negative mutation cannot be overcome by these two suppressor mutations. Therefore, the positive effects of A11V and I12V on dimerization of the SL3-deleted RNA must have taken place at the maturation stage.

RAGE is a multiligand receptor of the immunoglobulin superfamily: implications for homeostasis and chronic disease

Receptor for AGE (RAGE) is a member of the immunoglobulin superfamily that engages distinct classes of ligands. The biology of RAGE is driven by the settings in which these ligands accumulate, such as diabetes, inflammation, neurodegenerative disorders and tumors. In this review, we discuss the context of each of these classes of ligands, including advance glycation end-products, amyloid beta peptide and the family of beta sheet fibrils, S100/calgranulins and amphoterin. Implications for the role of these ligands interacting with RAGE in homeostasis and disease will be considered.

The Tat protein of human immunodeficiency virus type 1 (HIV-1) can promote placement of tRNA primer onto viral RNA and suppress later DNA polymerization in HIV-1 reverse transcription

Human immunodeficiency virus type-1 Tat has been proposed to play a role in the regulation of reverse transcription. We previously demonstrated that wild-type Tat can augment viral infectivity by suppressing the reverse transcriptase (RT) reaction at late stages of the viral life cycle in order to prevent the premature synthesis of potentially deleterious viral DNA products. Here we have performed a detailed analysis of the cell-free reverse transcription reaction to elucidate the mechanism(s) whereby Tat can affect this process. Our results show that Tat can suppress nonspecific DNA elongation while moderately affecting the specific initiation stage of reverse transcription. In addition, Tat has an RNA-annealing activity and can promote the placement of tRNA onto viral RNA. This points to a functional homology between Tat and the viral nucleocapsid (NC) protein that is known to be directly involved in this process. Experiments using a series of mutant Tat proteins revealed that the cysteine-rich and core domains of Tat are responsible for suppression of DNA elongation, while each of the cysteine-rich, core, and basic domains, as well as a glutamine-rich region in the C-terminal domain, are important for the placement of tRNA onto the viral RNA genome. These results suggest that Tat can play at least two different roles in the RT reaction, i.e., suppression of DNA polymerization and placement of tRNA onto viral RNA. We believe that the first of these activities of Tat may contribute to the overall efficiency of reverse transcription of the viral genome during a new round of infection as well as to enhanced production of infectious viral particles. We hypothesize that the second activity, illustrating functional homology between Tat and NC, suggests a potential role for NC in the displacement of Tat during viral maturation.

Structural and functional properties of the HIV-1 RNA-tRNA(Lys)3 primer complex annealed by the nucleocapsid protein: comparison with the heat-annealed complex

The conversion of the single-stranded RNA genome into double-stranded DNA by virus-coded reverse transcriptase (RT) is an essential step of the retrovirus life cycle. In human immunodeficiency virus type 1 (HIV-1), RT uses the cellular tRNA(Lys)3 to initiate the (-) strand DNA synthesis. Placement of the primer tRNA(Lys)3 involves binding of its 3'-terminal 18 nt to a complementary region of genomic RNA termed PBS. However, the PBS sequence is not the unique determinant of primer usage and additional contacts are important. This placement is believed to be achieved in vivo by the nucleocapsid domain of Gag or by the mature protein NCp. Up to now, structural information essentially arose from heat-annealed primer-template complexes (Isel et al., J Mol Biol, 1995, 247:236-250; Isel et al., EMBO J, 1999, 18:1038-1048). Here, we investigated the formation of the primer-template complex mediated by NCp and compared structural and functional properties of heat- and NCp-annealed complexes. We showed that both heat- and NCp-mediated procedures allow comparable high yields of annealing. Then, we investigated structural features of both kinds of complexes by enzymatic probing, and we compared their relative efficiency in (-) strong stop DNA synthesis. We did not find any significant differences between these complexes, suggesting that information derived from the heat-annealed complex can be transposed to the NCp-mediated complex and most likely to complexes formed in vivo.

HIV-1 nucleocapsid protein and the secondary structure of the binary complex formed between tRNA(Lys.3) and viral RNA template play different roles during initiation of (-) strand DNA reverse transcription

In human immunodeficiency virus type 1 (HIV-1), the tRNA(Lys.3) primer and viral RNA template can form a specific complex that is characterized by extensive inter- and intramolecular interactions. Initiation of reverse transcription from this complex has been shown to be distinguished from subsequent elongation by early pausing events, such as at the +1 and +3 nucleotide positions. One major concern regarding the biological relevance of these results is that most kinetic studies of HIV-1 reverse transcription have been performed using tRNA(Lys.3)-viral (v) RNA complexes that were formed by heat annealing. In contrast, tRNA(Lys.3) in viruses is placed onto the primer binding site by nucleocapsid (NC) sequences of the Gag protein. In this study, we have further characterized the initiation features of reverse transcription in the presence of HIV-1 NC protein. In contrast to results obtained with a heat-annealed tRNA(Lys.3).vRNA complex, we found that polymerization reactions catalyzed by HIV-1 reverse transcriptase did not commonly pause at the +1 nucleotide position when a NC-annealed RNA complex was used, and that this was true regardless whether NC was actually still present during reverse transcription. This activity of NC required both zinc finger motifs, as demonstrated by experiments that employed zinc finger-mutated forms of NC protein (H23C NC and ddNC), supporting the involvement of the zinc fingers in the RNA chaperone activity of NC. However, NC was not able to help reverse transcriptase to escape the +3 pausing event. Mutagenesis of a stem structure within the tRNA(Lys.3). vRNA complex led to disappearance of the +3 pausing event as well as to significantly reduced rates of reverse transcription. Thus, this stem structure is essential for optimal reverse transcription, despite its role in promotion of the +3 pausing event.

Hydrophobic amino acids in the human immunodeficiency virus type 1 p2 and nucleocapsid proteins can contribute to the rescue of deleted viral RNA packaging signals

An RNA fragment of 75 nucleotides, which is located between the primer binding site and the 5' major splice donor site in human immunodeficiency virus type 1, has been shown to participate in specific encapsidation of viral RNA. Compensation studies have identified two second-site mutations, namely, MP2 (a T12I substitution in p2) and MNC (a T24I substitution in the nucleocapsid [NC] protein) that were involved in the rescue of various deletions in the aforementioned RNA region (i.e., BH-D1, BH-D2, and BH-LD3). To study whether the MP2 and MNC point mutations exert their compensatory effects in a cis manner, production of Gag proteins was blocked by insertion of stop codons into LD3, LD3-MP2-MNC, and wild-type BH10 such that the constructs generated, i.e., LD3-DG, LD3-MP2-MNC-DG, and BH-DG, only provided RNA transcripts for packaging. The results of cotransfection experiments showed that the LD3-MP2-MNC-DG viral RNA was packaged as inefficiently as LD3-DG; in contrast, BH-DG was efficiently packaged. Therefore, nucleotide substitutions in MP2 and MNC did not act in a cis manner to correct the packaging deficits in LD3. Next, we deliberately changed the T12 in p2 or the T24 in the NC to each of 19 other amino acids. We found that amino acids with long hydrophobic side chains, i.e., V, L, I, and M, were favored at either position 12 in p2 or at position 24 in NC to compensate for the above-mentioned deletions. Further studies showed that only a few amino acids could not be used at these two sites by the wild-type virus due to decreased RNA levels in the virion or abnormal Gag protein processing. In this case, W, D, and E could not substitute for T12 in p2, and S, D, and N could not substitute for T24 in NC, without affecting viral infectivity. Therefore, the long hydrophobic side chains of V, L, I, and M are necessary for these amino acids to rescue the BH-D1, BH-D2, and BH-LD3 mutated viruses.

A novel microphysiometer based on MLAPS for drugs screening

This paper presents a novel microphysiometer for simultaneous measurements of several extracellular ions concentrations in living cells based on MLAPS (multi-light addressable potentiometric sensor). In the microphysiometer, different sensitive membranes are illuminated in parallel with n light sources at different frequencies, the response amplitudes of each frequency component can be measured on-line by parallel processing algorithm. By the experiments, we can analyze the relations of the extracellular environmental H(+), Na(+), K(+), Ca(2+) under the effects of western medicines (dilantin, phenobarbital sodium, penicillin sodium) and Chinese drugs (scutellaria, medlar, hemlock parsley), and estimate the effects of several drugs. As the novel microphysiometer works under regular cell culture conditions, cells can be repeatedly simulated with drugs to complete dose-response curve within a few hours. With the detection of a general parameter (extruded protons and ions), the system can be used to monitor the real-time process of the cells' metabolism, observe the functional responses of different kinds of membrane-bound receptors, evaluate the drugs.