Efficacy and safety of oral Chinese patent medicines in the treatment of coronary heart disease combined with hyperlipidemia: a systematic review and network meta-analysis of 78 trials

AIM OF THE STUDY

To evaluate the clinical efficacy and safety of commonly used oral Chinese patent medicines for the treatment of coronary heart disease combined with hyperlipidemia in clinical practice through a network meta-analysis.

MATERIALS AND METHODS

PubMed, Embase, Cochrane Library, Web of Science, Wanfang, VIP, SinoMed, and CNKI databases were searched for all published randomized controlled trials (RCTs) on the treatment of coronary heart disease combined with hyperlipidemia using Chinese patent medicines. NoteExpress software was used to screen the literature obtained from the databases according to the inclusion and exclusion criteria. The Cochrane risk of bias assessment tool was used to evaluate the quality of the included studies. A network meta-analysis was performed using R 4.2.1. Subgroup analyses of outcome indicators were made based on conventional treatment (CT) methods. The incidence of adverse events in the included RCTs was statistically analyzed. A funnel plot was drawn using RevMan 5.4.1 software for the assessment of bias in the total clinical effectiveness rate. Finally, the quality of evidence for interventions with statistically significant differences was evaluated using the GRADE system.

RESULTS

A total of 78 RCTs were included, involving 7,955 cases and 8 types of Chinese patent medicines, which were Tongxinluo Capsule, Naoxintong Capsule, Compound Danshen Dripping Pill, Shexiangbaoxin Pill, Songling Xuemaikang Capsule, Xuezhikang Capsule, Yindan Xinnaotong Capsule, and Zhibitai Capsule. A total of 24 RCTs reported the incidence of adverse events, but no statistically significant difference in the incidence of adverse events was found between the experimental and control groups in each study (P > 0.05). There was no obvious publication bias in all studies, but the overall quality of evidence in the included RCTs was low. Comparison of different intervention measures showed that Naoxintong Capsule + CT improved the cardiac index and cardiac output, and lowered the low-density lipoprotein cholesterol and total cholesterol levels. Tongxinluo Capsule + CT raised high-density lipoprotein cholesterol levels and reduced triglyceride levels. Xuezhikang Capsule + CT improved the total clinical effectiveness rate. Subgroup analyses showed that differences in CT did not cause heterogeneity in the results.

CONCLUSION

Compared with the use of CT alone, the combined use of Chinese patent medicines with CT can effectively improve the symptoms in patients with both coronary heart disease and hyperlipidemia.

Inulin-induced differences on serum extracellular vesicles derived miRNAs in dairy cows suffering from subclinical mastitis

MicroRNA (miRNA) profiles vary with the nutritional and pathological conditions of cattle. In this study, we aimed to investigate the effects of inulin supplement on miRNA profiles derived from serum extracellular vesicles (EVs). Our goal was to determine the differences in miRNA expressions and analyse the pathways in which they are involved. Based on the results of California mastitis test and milk somatic cell counts, ten lactating cows with subclinical mastitis were randomly divided into two groups: an inulin group and a control group (n = 5 in each group). The inulin group received a daily supplement of 300 g of inulin while the control group did not receive any supplementation. After a 5-week treatment period, serum-derived EV-miRNAs from each cow were isolated. High-throughput sequencing was conducted to identify differentially expressed miRNAs. GO and KEGG bioinformatics analysis was performed to examine the target genes of these differentially expressed miRNAs. The EV-RNA concentration and small RNA content were not affected by the inulin treatment. A total of 162 known miRNAs and 180 novel miRNAs were identified from 10 samples in the two groups. Among the known miRNAs, 23 miRNAs were found to be differentially expressed between the two groups, with 18 upregulated and five downregulated in the inulin group compared to the control group. Pathway analysis revealed the involvement of these differentially expressed miRNAs in the regulation of cell structure and function, lipid oxidation and metabolism, immunity and inflammation, as well as digestion and absorption of nutrients. Overall, our study provides a molecular-level explanation for the reported beneficial health effects of inulin supplementation in cows with subclinical mastitis.

Effect of different glucogenic to lipogenic nutrient ratios on rumen fermentation and bacterial community in vitro

Aims

This study was to investigate the effect of different ratios of glucogenic to lipogenic nutrients on rumen fermentation and the corresponding ruminal bacterial communities.

Methods and Results

Four diets, including glucogenic diet (G), lipogenic diet (L), two mixed diets: GL1 (G: L = 2 : 1) and GL2 (G:L = 1 : 2), served as substrates and were incubated with rumen fluid in vitro. The results revealed that the gas production, dry matter digestibility and propionate proportion were significantly increased by the G diet than others. The G diet increased the bacterial genera of Succinivibrionaceae_UCG_002, Succinivibrio, Selenomonas_1 and Ruminobacter but decreased some cellulolytic bacteria including the Eubacterium and several genera in family Ruminococcaceae than others.

Conclusions

When the glucogenic nutrient was above 1/3 of the dietary energy source among the four diets, the in vitro incubation had a higher feed digestibility and lower acetate to propionate ratio. Bacterial genera, including Selenomonas, Succinivibrio, Ruminobacter, certain genera in Ruminococcaceae, Christensenellaceae_R‐7_group and Eubacterium, were more sensitive to the glucogenic to lipogenic nutrients ratio.

Significance and Impact of the Study

The present study provides a new perspective about the effect of dietary glucogenic to lipogenic ingredient ratios on rumen metabolism by comparing end‐products, gas production and bacterial composition via an in vitro technique.

Blockage of PAK1 alleviates the proliferation and invasion of NSCLC cells via inhibiting ERK and AKT signaling activity

PURPOSE

P21-activated kinase 1 (PAK1), a serine/threonine protein kinase which functions downstream of RAC and CDC42 GTPase, is activated by a variety of stimuli, including RAS and other growth signaling factors. The extracellular signal kinase (ERK) and protein kinase B (AKT) signal pathways have been implicated in the pathogenesis of cancers. Whether PAK1 is sensitive to KRAS mutation signals and plays a role through ERK and AKT signaling pathways in NSCLC needs to be studied.

METHODS

The expression of PAK1, ERK and AKT was detected in both lung cancer cell lines and clinical samples. PAK1 RNA interference and specific inhibitor of PAK1(IPA-3) were applied to lung cancer cell lines and mouse xenograft tumors. Cell growth was measured by MTT and colony formation assays. Cell migration and invasion were detected by wound healing and transwell assays. RAS mutation was detected by Taqman probe method. Correlation between KRAS, PAK1, ERK and AKT activities was analyzed in lung cancer patients.

RESULTS

PAK1 was highly expressed not only in RAS mutant but also in RAS wild-type lung cancer cells. Using specific inhibitor of PAK1, IPA-3 and PAK1 RNA interference, cell proliferation, migration and invasion of lung cancer cells were reduced significantly, accompanied by decreased activities of ERK and AKT. Dual inhibition of ERK and AKT suppressed these cellular processes to levels comparable to those achieved by reduction in PAK1 expression. In NSCLC patients, PAK1 was not correlated with KRAS mutation but was significantly positively correlated with pERK and pAKT.

CONCLUSION

PAK1 played roles in NSCLC proliferation and invasion via ERK and AKT signaling and suggested a therapeutic target for NSCLC.

Obesity inversely correlates with prostate-specific antigen levels in a population with normal screening results of prostate cancer in northwestern China

Serum prostate-specific antigen (PSA) is a diagnostic biomarker of prostate cancer and is possibly associated with obesity. This study aimed to explore the relationships between obesity indicators [body mass index (BMI) and waist circumference (WC)] with PSA in Chinese men. A cross-sectional study of men aged 30-85 years undergoing prostate cancer screening was conducted from August 2008 to July 2013 in Xi'an, China. Data were obtained from clinical reports, condition was recorded based on self-report including demographics, weight, height, and WC (>90 cm=obese). Fasting blood glucose (FBG) and prostate volume (PV) were assessed clinically. Patients were grouped by BMI (normal=22.9, overweight=23-27.4, obese≥27.5 kg/m²). PSA parameters of density (PSAD), PSA serum level, and PSA increasing rate per year (PSAR) were calculated per BMI and age groups (30-40, 41-59, 60-85 years). Obesity indicators (BMI and WC) and PSA parameter relationships were modeled by age-stratified linear regression. Of 35,632 Chinese men surveyed, 13,084 were analyzed, including 13.44% obese, 57.44% overweight, and 29.12% normal weight, according to BMI; 25.84% were centrally (abdominally) obese according to WC. BMI and WC were negatively associated with all PSA parameters, except PSAD and PSAR [P<0.05, BMI: β=-0.081 (95%CI=-0.055 to -0.036), WC: β=-0.101 (-0.021 to -0.015)], and independent of FBG and PV (P<0.05) in an age-adjusted model. In conclusion, obesity was associated with lower PSA in Chinese men. Therefore, an individual's BMI and WC should be considered when PSA is used to screen for prostate cancer.

[Let-7 miRNA silencing promotes Kaposi's sarcoma-associated herpesvirus lytic replication via activating mitogen-activated protein kinase kinase kinase kinase 4 and its downstream factors]

OBJECTIVE

To explore the effect of let-7 miRNA silencing on Kaposi's sarcoma-associated herpesvirus (KSHV) lytic replication and the underling mechanism.

METHODS

The pEGFP-C2-let-7 sponge vector was transfected into BCBL-1 and 293T cells with Lipofectamine 2000 to silence the expression of let-7 miRNAs. Quantitative real-time PCR (qRT-PCR) was used to quantify the expression of let-7 miRNAs, the transcriptional levels of mitogen-activated protein kinase kinase kinase kinase 4 (MAP4K4), cyclooxygenase-2 (COX-2) and matrix metalloproteinase 13 (MMP-13), and the DNA copy numbers of KSHV open reading frame 50 (ORF50) and open reading frame 72 (ORF72). Western blot was used to detect the total and phosphorylated protein levels of MAP4K4, COX-2, extracellular regulated protein kinases (ERK1/2), c-Jun N-terminal kinase (JNK) and p38 MAPK.

RESULTS

The expression of let-7 miRNAs was dramatically decreased in the let-7 sponge transfected BCBL-1 and 293T cells compared with that in the vector-transfected cells (P<0.05 for all). The gene copy number and mRNA transcriptional level of KSHV ORF50 were significantly increased in the let-7 sponge transfected BCBL-1 cells compared with that in the vector-transfected cells (1.00±0.10 vs. 2.33±0.18 and 1.08±0.48 vs 3.22±0.27, respectively,P<0.001 for both). The gene copy number and mRNA transcriptional level of KSHV ORF72 were also significantly increased in let-7 sponge transfected BCBL-1 cells compared with those in the vector-transfected cells(1.07±0.49 vs 1.67±0.45 and 1.01±0.19 vs 1.54±0.11, respectively,P<0.05 for both). Furthermore, the mRNA transcriptional levels of MAP4K4, COX-2 and MMP-13 were significantly increased in the let-7 sponge transfected BCBL-1 cells compared with those in the vector-transfected cells (1.00±0.05 vs 5.73±0.96, 1.00±0.05 vs 2.68±0.19, 1.00±0.02 vs 2.69±0.25, respectively,P<0.001 for all). Let-7 miRNAs silencing also increased the protein expression levels of MAP4K4, COX-2 and phospho-ERK1/2, while the phospho-JNK and phospho-p38 were not changed in the BCBL-1 and 293T cells.

CONCLUSIONS

Let-7 silencing may activate the replication of KSHV, possibly through up-regulating MAP4K4 and its downstream molecules COX-2, MMP-13, and phosphorylation of ERK1/2, finally results in the progression of Kaposi sarcoma.

HPV genotype analysis for women in Shaanxi Province of China

The aim of this study was to examine the subtype distribution of human papilloma virus (HPV) in women in the Shaanxi Province of China. A DNA chip, along with polymerase chain reaction amplification and reverse dot blot technology, was adopted to analyze the HPV genotypes of 22,937 cases of cervical cell specimens. The HPV infection rate was 18.70%, wherein high-risk, low-risk, and high- and low-risk multiple infection rates were 15.75, 2.96 and 1.91%, respectively. High-risk infections accounted for 84.20% of total infections. The rate of HPV infection in women with rural residence, high school education or less, a low income, or age over 40 years was significantly higher than that in the control group (negative HPV infection women). Of the 18 detected high-risk HPV subtypes, the most common in single infections were, in the order of prevalence, HPV16, 58, 18, 52, 33, and 56. For multiple high-risk infections, the most common subtypes in the order of prevalence were HPV16, 52, 58, 18, 56, and 33. Age was a factor in the rate of infection, as the 41-50-year age group had a significantly higher risk of infection than the other groups (P < 0.05). In multiple infections, double infections were common, accounting for 77.10% of multiple infections, and triple or more infections were more common in women aged 51-60 years. In Shaanxi Province, high-risk HPV infection in women was mainly attributed to rural residence, age over 40 years, low income, and low education level.

Low levels of serum miR-99a is a predictor of poor prognosis in breast cancer

MicroRNA (miRNA) deregulation has been previously linked to the initiation and development of breast cancer. Although miR-99a is aberrantly expressed in many types of cancers, including breast cancer, the serum miR-99a expression level in breast cancer and its clinical significance remains unknown. Blood samples were obtained from 72 patients with breast cancer and 40 healthy volunteers, and subjected to real-time polymerase chain reaction to evaluate the level of expression of serum miR-99a in the study participants. Furthermore, we investigated the association between serum miR-99a and the clinical outcome of breast cancer. Serum miR-99a expression was significantly downregulated in patients with breast cancer, compared to that in healthy controls (P < 0.01). Moreover, the serum miR-99a was correlated with various clinical parameters of breast cancer, including lymph node metastasis (P = 0.0194), distant metastasis (P = 0.0037), Ki67 intensity (P = 0.0164), TNM stage (P = 0.0096), and histological grade (P = 0.0051) of cancer. Additionally, breast cancer patients displaying lower miR-99a levels showed poorer overall survival rates (P = 0.0411). The serum miR-99a level was also found to be an independent risk factor for breast cancer (hazard ratio = 3.176, 95% confidence interval = 1.543-7.360, P = 0.023). Our data indicated that serum miR-99a expression was downregulated in breast cancer patients; moreover, this downregulation was associated with poor prognosis, suggesting that serum miR-99a could function as a tumor suppressor in breast cancer.

Hsa-miRNA-31 regulates epithelial cell barrier function by inhibiting TNFSF15 expression

Ulcerative colitis (UC) is characterized by epithelial barrier disruption and alterations in immune regulation but with the etiology unknown. MicroRNA-31 is the most consistent differentially expressed miRNA in ulcerative colitis tissue. The aim of this project is to study the important roles of miRNA-31 in regulation of intestinal epithelial barrier function. We found that expression of miRNA-31 is proportional to the proliferation of Caco2-BBE cells and overexpression of miRNA-31 can increase its trans-epithelial resistance (TER) by decreasing the transepithelial permeability. miRNA-31 can directly bind to the 3-UTR of TNFSF15, thereafter negatively regulating its expression in Caco2-BBE cells. BrdU and TUNEL analysis demonstrated that transfection of miRNA-31 stimulates proliferation or apoptosis-resistance. Taken together, these results revealed a novel mecha-nism underlying the regulation of epithelial barrier function by miRNA-31 during its regulation on proliferation of epithelial cells.

Prevalence of human papillomavirus genotypes among women with cervical lesions in the Shaanxi Province of China

This study aimed to investigate human papilloma virus (HPV) genotypes among women with cervical lesions in Shaanxi Province, China, to obtain information regarding cervical lesion prevention and treatment. The study included 4508 HPV-positive subjects; cervical swab specimens were collected and tested for HPV infection status and HPV genotypes using polymerase chain reaction and reverse dot-blot hybridization. Women positive for HPV with cervical lesions, including chronic cervicitis, cervical intraepithelial neoplasia, and cervical squamous cell carcinoma (SCC), were examined; HPV-positive women with no cervical lesions were controls. Data were pooled and weighted estimates have been presented. For women with no cervical lesions and positive for one HPV genotype, HPV 52, 16, 58, 81, 33, and 56 were the most common; for multiple-HPV genotype infection, HPV 16, 52, 6, 18, 58, and 66 were the most common. Collectively, HPV 16, 58, 52, 18, 33, and 81 were the most common in women with cervical lesions. HPV 16 comprised 26.71% of single-genotype and 15.64% of multiple-genotype infections. The proportion of HPV-16-positive cases was 29.15%, which was the highest among all HPV genotypes (P < 0.01). Single-HPV genotype infection was the most common in cervical HPV infection (77.48%); infection with two HPV genotypes comprised 72.22% of multiple-genotype infections. The proportion of single-low-risk HPV genotype infections decreased with increase in cervical lesion severity; there were no single- or multiple-low-risk genotype HPV infections in cervical SCC patients. The proportion of multiple-genotype HPV infections with at least one high-risk genotype increased with cervical lesion severity.

TRAF3IP3, a novel autophagy up-regulated gene, is involved in marginal zone B lymphocyte development and survival

Tumour necrosis factor receptor-associated factor 3 (TRAF3) interacting protein 3 (TRAF3IP3; also known as T3JAM) is expressed specifically in immune organs and tissues. To investigate the impact of TRAF3IP3 on immunity, we generated Traf3ip3 knock-out (KO) mice. Interestingly, these mice exhibited a significant reduction in the number of common lymphoid progenitors (CLPs) and inhibition of B cell development in the bone marrow. Furthermore, Traf3ip3 KO mice lacked marginal zone (MZ) B cells in the spleen. Traf3ip3 KO mice also exhibited a reduced amount of serum natural antibodies and impaired T cell-independent type II (TI-II) responses to trinitrophenol (TNP)-Ficoll antigen. Additionally, our results showed that Traf3ip3 promotes autophagy via an ATG16L1-binding motif, and MZ B cells isolated from mutant mice showed a diminished level of autophagy and a high rate of apoptosis. These results suggest that TRAF3IP3 contributes to MZ B cell survival by up-regulating autophagy, thereby promoting the TI-II immune response.

Corticotropin Releasing Hormone Modulates Endotoxin-Induced Inflammatory Cytokine Expression in Human Trophoblast Cells

Recent studies have suggested a significant increase in corticotropin releasing hormone (CRH) in maternal plasma and placenta during the course of maternal infection. The aim of this study was to examine the possible role of CRH in lipopolysaccharide (LPS)-induced pro-inflammatory cytokine expression using the well-established human extravillous trophoblast cell line HTR-8/SVneo. Exposure of the HTR-8/SVneo cells to LPS resulted in increased secretion of tumour necrosis factor alpha (TNF-alpha) and interleukin (IL)-8. Pre-treatment of the cells with CRH prior to LPS exposure significantly enhanced LPS induced TNF-alpha and IL-8 secretion. This effect was inhibited by the CRH antagonist astressin. Stimulation of the cells with CRH caused a rapid and transient phosphorylation of p38/MAPK while CRH had no effect on ERK1/2 activation. The effect of CRH on p38/MAPK activation was suppressed by astressin and by the p38/MAPK inhibitor SB203580. Exposure of the cells to CRH resulted in increased expression of TLR-4 and this effect was also inhibited by astressin. Taken together, these findings suggest that CRH augments LPS induced cytokine secretion in human trophoblast cells. Modulation of LPS induced immune responses by CRH may be mediated through regulation of TLR-4 and selective activation of the p38/MAPK signalling pathway.

Gelatinolytic activity of matrix metalloproteinase-2 and matrix metalloproteinase-9 in rat brain after implantation of 9L rat glioma cells

The matrix metalloproteinases (MMPs) have come to be highlighted by their close relation to the cell invasion of gliomas. The inhibitors of MMPs have undergone extensive development because of its effectiveness against tumor invasion and angiogenesis. Therefore, a suitable animal model is necessary for searching new MMPs inhibitors against gliomas. In this study, we established an experimental model by implanting 9L glioma cells stereotactically into Fisher344 (F344) rat's brain, and the expression and enzymatic activity of MMP-2 and MMP-9 in 9L glioma cells and in tumor tissue was determined by means of reverse transcription polymerase chain reaction (RT-PCR), sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) zymography, in situ film zymography and immunostaining. The results of RT-PCR showed that the mRNA level of MMP-2 in 9L glioma cells was higher than that of MMP-9, and the mRNA expression of MMP-9 was increased along with the growth of malignant gliomas. SDS-PAGE zymography revealed that the expression of MMP-2 and MMP-9 were significantly increased in tumor tissues, and the MMP-9 wasn't detected in normal tissue. The positive stain of MMP-2 and MMP-9 was enhanced with the growth of malignant gliomas, especially for MMP-9. The expression of active gelatinase was found in tumor tissue. In conclusion, the expression of active MMP-2 and MMP-9 was increased in 9L/F344 rat brain during the growth of malignant gliomas at different time intervals, which indicate that 9L/F344 animal model may be a prospective animal model to test new MMPs inhibitors.

Development of an Ad7 cosmid system and generation of an Ad7deltaE1deltaE3HIV(MN) env/rev recombinant virus

A strategy to circumvent immune responses to adenovirus (Ad) resulting from natural infection or repeated vector administrations involves sequential use of vectors from different Ad serotypes. To further develop an Ad-HIV recombinant AIDS vaccine approach, a replication-defective recombinant Ad from a non-subgroup C virus was required. Using a cosmid system, we generated an Ad7deltaE1deltaE3HIV(MN) env/rev recombinant virus and compared expression of the inserted HIV genes with a similarly constructed replication-competent Ad7deltaE3HIV(MN)env/rev recombinant. Ad7deltaE1deltaE3HIV(MN)env/rev expressed both HIV env and rev gene products. The envelope protein was correctly processed and functional, mediating syncytia formation of Ad7deltaE1deltaE3HIV(MN) env/rev-infected cells and CD4(+) T lymphocytes. Ad7deltaE1deltaE3HIV(MN)env/rev could be amplified on 293-ORF6 cells, containing the E4 ORF6 gene, shown earlier to support production of an Ad7 vector lacking the E1a gene. The utility of this cell line is now extended to the production of replication-defective Ad7 recombinants lacking E1a, E1b, and protein IX genes. Sequential immunizations with Ad-HIV recombinants based in different Ad serotypes have been shown to effectively elicit both humoral and cellular HIV-specific immune responses. The recombinant Ad7deltaE1deltaE3HIV(MN)env/rev will be useful in such AIDS vaccine strategies. Further, these studies have created new cosmid vectors that can be applied to generation of single- or double-deleted Ad7 recombinants with foreign genes inserted into the E1 and/or E3 regions.

[Clinical application of three-dimensional spiral CT in the complex maxillofacial fractures]

OBJECTIVE

The aim of this study was to evaluate the clinical application of the three-dimensional spiral CT in the complex maxillofacial fractures.

METHODS

A total of 26 patients with complex maxillofacial fractures were examined using spiral CT with the slice thickness of 3 to 5 mm. The surface shaded display (SSD) method was used for reconstruction of the three-dimensional (3D) images. The three-dimensional images of maxillofacial fractures were obtained by using various rotations. Before the three-dimensional images were reconstructed, the drawing and deleting way was used for these mandibular fractures.

RESULTS

The method demonstrated clearly the three-dimensional anatomy and their relationships of the fractures; using the drawing and deleting way, location and move condition of mandibular fractures, especially condylar fractures, were showed clearly.

CONCLUSION

The three-dimensional CT is important in evaluating complex maxillofacial fractures. It could be used to demonstrate clearly locations and move conditions of complex maxillofacial fractures and operative plans.

The biological functions of the methyl-CpG-binding protein MeCP2 and its implication in Rett syndrome

Methylation of DNA is essential for development in the mouse and plays an important role in inactivation of the X-chromosome, genomic imprinting and gene silencing. The properties of the methyl-CpG binding proteins (MeCPs) are being proved to be the key to interpreting the connection between DNA methylation and transcriptional repression. The founder member of the family, MeCP2, consists of a single polypeptide that contains both a methyl-CpG binding domain (MBD) and transcriptional repression domain (TRD). MBD binds to a single symmetrically methylated CpG site and is responsible for chromatin localization of the protein. NMR studies have revealed that the MBD adopts a wedge-shaped molecular structure. The TRD interacts with Sin3, which is known to form complexes with histone deacetylases. MeCP2-mediated transcriptional repression may involve two distinct mechanisms, one being dependent on chromatin modification by histone deacetylation and the other being chromatin independent. Mutations in MeCP2 gene cause the X-linked neurodevelopmental disease Rett syndrome. The spectrum of mutations reflects the importance of the MBD and TRD domains. We speculate that abnormal gene expression in Rett patients leads to dysfunction of the central nervous system. We propose a genetic therapeutic approach based on activation of the wild type copy of the MeCP2 gene located in the inactive X chromosome.

Expression and postnatal changes of adrenergic receptor subtype mRNA in rat submandibular glands

Adrenergic receptors (ARs) are involved in regulating saliva secretion and composition in salivary glands. Nine AR subtypes, including three alpha1-ARs (alpha1a-, alpha1b- and alpha1d-ARs), three alpha2-ARs (alpha2A-, alpha2B- and alpha2C-ARs) and three beta-ARs (beta1,beta2- and beta3-ARs), have been identified through molecular cloning. The five subtype genes, alpha1a-, alpha1b-, alpha2A-, beta1-, and beta2-ARs, were expressed in rat submandibular glands. In contrast, the other four subtype mRNAs, alpha1d-, alpha2B-, alpha2C- and beta3-ARs, were not detected by reverse transcription-polymerase chain reaction (RT-PCR). The steady-state mRNA expression for the five AR subtypes in rat submandibular glands was measured by quantitative competitive RT-PCR using synthetic DNA as internal standard at different stages of postnatal development. The relative rank order of AR subtype mRNA expression was alpha1a>beta2>beta1>alpha2A>alpha1b at all stages except that beta1- and alpha2A-subtypes were reversed at 2 weeks of age. The gene expression of alpha1a-AR subtype relative to total AR was low at 2 weeks of age and increased and reached a maximum at 6 weeks of age, whereas those patterns of alpha2A-, beta1- and beta2-AR subtypes were similar to each other and their gene expressions were high at 2 weeks of age and then decreased. On the other hand, the gene expression of alpha1b-AR subtype did not change over the different stages in relation to that of a housekeeping gene, glyceraldehyde 3-phosphate dehydrogenase, and to total AR. Although rat submandibular glands contain the five AR subtype mRNAs, distinct subtype-specific expression is evident.

Effect of MCI-154, a calcium sensitizer, on calcium sensitivity of myocardial fibers in endotoxic shock rats

This study was designed to investigate the effect of a calcium sensitizer on the Ca2+ sensitivity of myocardial fibers in endotoxic shock rats. Right ventricular papillary muscles from sham shock or endotoxic shock rats were skinned by incubation in saponin solution. Forces of the skinned muscles were recorded when they were activated sequentially by different pCa (-log[Ca2+]) activating solutions with or without positive inotropic agents. Tension-pCa relationship curve of skinned fibers delineated the affinity of troponin C(TnC) for Ca2+ and the medium value pCa50 (pCa required for producing 50% of maximal Ca2+-activated tension) was taken as the quantitative index of Ca2+ sensitivity of TNC. It was found that the maximal Ca2+ activated tension (Tmax) was lower, tension-pCa relationship curve was shifted rightward, and the pCa50 was reduced significantly in endotoxic shock group compared with that of sham shock group. Milrinone could not counteract the above abnormalities. However, when skinned right ventricular papillary fibers from endotoxic shock rats were dealt with activating solutions containing 1 x 10(-5) M MCI-154, the Tmax was significantly increased, the tension-pCa relationship curve was shifted leftward. The pCa50 in MCI-154 group was increased to an extent similar to that of sham shock group and markedly higher than the values of endotoxic shock group and milrinone group. Furthermore, such effects of MCI-154 were concentration dependent. It can been concluded that the sensitivity of cardiac contractile proteins to Ca2+ in endotoxic shock rats is decreased. MCI-154, a calcium sensitizer, can significantly reverse the decreased sensitivity and increase Tmax of myocardial muscles from endotoxic shock rats.

Effects of MCI-154, a calcium sensitizer, on cardiac dysfunction in endotoxic shock in rabbits

This study was designed to observe the effects of MCI-154, a calcium sensitizer, on cardiac dysfunction after endotoxic shock in rabbits. Ten hours after the rabbits were given injection of 1.0 mg/kg endotoxin (Escherichia coli, O111:B4) via marginal ear veins, 0.1 mg/kg MCI-154 was injected intravenously and then 50 mL/kg normal saline (NS) + 0.1 mg/kg MCI-154 was infused continuously at a rate of 0.7 mL/min. During this process, the parameters of cardiac function were measured. It was found that 10 h after the endotoxin injection, heart rate (HR) was increased significantly while the mean arterial blood pressure (MAP), left ventricular systolic pressure (LVSP), isovolumetric pressure (IP), myocardial contractility (MC), and the area of p-dp/dt(max) vector loop (Lo) all were markedly decreased. Treatment with 50 mL/kg NS alone had slight effects on these parameters. On the contrary, LVSP, IP, MC, and Lo all were increased significantly while HR was not obviously changed and left ventricular end-diastolic pressure (LVEDP) was reduced remarkably following MCI-154 administration in endotoxic shock rabbits. The parameters of myocardial contractility were improved nearly to the values in sham shock group and were markedly higher than that in NS alone-treated group. It can be concluded that MCI-154 can exert significant therapeutic effects on cardiac dysfunction after endotoxic shock, for it improves cardiac function, dilates peripheral blood vessels, and slightly affects HR.

The solution structure of the domain from MeCP2 that binds to methylated DNA

MeCP2 is an abundant mammalian protein that binds methylated CpG (mCpG) sequences within double-stranded DNA, represses transcription by recruiting histone deacetylases, and is essential for embryonic development. It is one of a family of proteins which mediate the biological consequences of DNA methylation. These proteins each possess a sequence motif of about 70 residues which, in MeCP2, form a domain necessary and sufficient for binding to mCpG. The solution structure of the mCpG-binding domain (MBD) from MeCP2 has been solved and the DNA-binding surface of the domain mapped using NMR spectroscopy. Residues 95-162 of MeCP2 adopt a novel fold forming a wedge-shaped structure. An N-terminal four-stranded antiparallel beta-sheet forms one face of the wedge, while the other face is formed mainly by a C-terminal helical region. The thin end of the wedge is extended by a long loop between beta-strands B and C containing many basic residues. The B-C loop together with residues in strands B, C and D, and at the N terminus of the alpha-helix, appears to form an interface with methylated DNA. Unstructured residues at the NH2 terminus of the domain are also involved in formation of the complex. The presence of numerous arginine and lysine side-chains on the DNA-binding surface of MBD is consistent with the requirement for the mCpG site to be flanked by non-specific sequences of base-pairs. The absence of symmetry in the domain implies that recognition does not exploit the symmetry of the binding site. A conserved hydrophobic pocket containing the side-chains of Tyr123 and Ile125 on the positively charged beta-sheet face is a candidate for the region of contact with the methyl-groups of the modified cytosine residues.

Transcriptional repression by the methyl-CpG-binding protein MeCP2 involves a histone deacetylase complex

Cytosine residues in the sequence 5'CpG (cytosine-guanine) are often postsynthetically methylated in animal genomes. CpG methylation is involved in long-term silencing of certain genes during mammalian development and in repression of viral genomes. The methyl-CpG-binding proteins MeCP1 and MeCP2 interact specifically with methylated DNA and mediate transcriptional repression. Here we study the mechanism of repression by MeCP2, an abundant nuclear protein that is essential for mouse embryogenesis. MeCP2 binds tightly to chromosomes in a methylation-dependent manner. It contains a transcriptional-repression domain (TRD) that can function at a distance in vitro and in vivo. We show that a region of MeCP2 that localizes with the TRD associates with a corepressor complex containing the transcriptional repressor mSin3A and histone deacetylases. Transcriptional repression in vivo is relieved by the deacetylase inhibitor trichostatin A, indicating that deacetylation of histones (and/or of other proteins) is an essential component of this repression mechanism. The data suggest that two global mechanisms of gene regulation, DNA methylation and histone deacetylation, can be linked by MeCP2.

Gene silencing by methyl-CpG-binding proteins

An important consequence of CpG methylation is the local silencing of gene expression. In part this can be mediated by direct interference of methylation with the binding of transcription factors. The major component of silencing, however, appears to be the binding of repressors that have an affinity for methyl-CpG. We have studied two proteins that bind to methylated DNA, methyl-CpG-binding protein 1 (MeCP1) and MeCP2. MeCP2 is a relatively abundant chromosomal protein whose localization in the nucleus is primarily dependent on CpG methylation. We find that MeCP2 is a potent transcriptional repressor with a genome-wide distribution. MeCP1 requires multiple methylated CpGs for binding and has previously been implicated as a methyl-CpG-dependent transcriptional repressor. Recent cloning of a candidate gene for a component of MeCP1 may provide clues to its mechanism of action.

A component of the transcriptional repressor MeCP1 shares a motif with DNA methyltransferase and HRX proteins

Methylation of cytosines within the sequence CpG is essential for mouse development and has been linked to transcriptional suppression in vertebrate systems. Methyl-CpG binding proteins (MeCPs) 1 and 2 bind preferentially to methylated DNA and can inhibit transcription. The gene for MeCP2 has been cloned and a methyl-CpG binding domain (MBD) within it has been defined. A search of DNA sequence databases with the MBD sequence identified a human cDNA with potential to encode an MBD-like region. Sequencing of the complete cDNA revealed that the open reading frame also encodes two cysteine-rich domains that are found in animal DNA methyltransferases (DNMTs) and in the mammalian HRX protein (also known as MLL and All-1). HRX is related to Drosophila trithorax. The protein, known as Protein Containing MBD (PCM1), was expressed in bacteria and shown to bind specifically to methylated DNA. PCM1 also repressed transcription in vitro in a methylation-dependent manner. A polyclonal antibody raised against the protein was able to 'supershift' the native MeCP11 complex from HeLa cells, indicating that PCM1 is a component of mammalian MeCP1.

MeCP2 is a transcriptional repressor with abundant binding sites in genomic chromatin

MeCP2 is an abundant mammalian protein that binds to methylated CpG. We have found that native and recombinant MeCP2 repress transcription in vitro from methylated promoters but do not repress nonmethylated promoters. Repression is nonlinearly dependent on the local density of methylation, becoming significant at the density found in bulk vertebrate genomic DNA. Transient transfection using fusions with the GAL4 DNA binding domain identified a region of MeCP2 that is capable of long-range repression in vivo. Moreover, MeCP2 is able to displace histone H1 from preassembled chromatin that contains methyl-CpG. These properties, together with the abundance of MeCP2 and the high frequency of its 2 bp binding site, suggest a role as a global transcriptional repressor in vertebrate genomes.

DNA methylation specifies chromosomal localization of MeCP2

MeCP2 is a chromosomal protein that is concentrated in the centromeric heterochromatin of mouse cells. In vitro, the protein binds preferentially to DNA containing a single symmetrically methylated CpG. To find out whether the heterochromatic localization of MeCP2 depended on DNA methylation, we transiently expressed MeCP2-LacZ fusion proteins in cultured cells. Intact protein was targeted to heterochromatin in wild-type cells but was inefficiently localized in mutant cells with low levels of genomic DNA methylation. Deletions within MeCP2 showed that localization to heterochromatin required the 85-amino-acid methyl-CpG binding domain but not the remainder of the protein. Thus MeCP2 is a methyl-CpG-binding protein in vivo and is likely to be a major mediator of downstream consequences of DNA methylation.

Studies of DNA methylation in animals

We have been studying the evolution and function of DNA methylation in vertebrate animals using three related approaches. The first is to further characterise proteins that bind to methylated DNA. Such proteins can be viewed as 'receptors' of the methyl-CpG 'ligand' that mediate downstream consequences of DNA modification. The second approach involves CpG islands. These patches of non-methylated DNA coincide with most gene promoters, but their origin and functional significance have only recently become the subject of intensive study. The third approach is to trace the evolution of DNA methylation. Genomic methylation patterns of vertebrates are strikingly different from those of invertebrates. By studying methylation in animals that diverged from common ancestors near to the invertebrate/vertebrate boundary, we will assess the possibility that changes in DNA methylation contributed causally to the evolution of the complex vertebrate lineage.

Purification of CpG islands using a methylated DNA binding column

CpG islands are short stretches of DNA containing a high density of non-methylated CpG dinucleotides, predominantly associated with coding regions. We have constructed an affinity matrix that contains the methyl-CpG binding domain from the rat chromosomal protein MeCP2, attached to a solid support. A column containing the matrix fractionates DNA according to its degree of CpG methylation, strongly retaining those sequences that are highly methylated. Using this column, we have developed a procedure for bulk isolation of CpG islands from human genomic DNA. As CpG islands overlap with approximately 60% of human genes, the resulting CpG island library can be used to isolate full-length cDNAs and to place genes on genomic maps.

Dissection of the methyl-CpG binding domain from the chromosomal protein MeCP2

MeCP2 is a chromosomal protein which binds to DNA that is methylated at CpG. In situ immunofluorescence in mouse cells has shown that the protein is most concentrated in pericentromeric heterochromatin, suggesting that MeCP2 may play a role in the formation of inert chromatin. Here we have isolated a minimal methyl-CpG binding domain (MBD) from MeCP2. MBD is 85 amino acids in length, and binds exclusively to DNA that contains one or more symmetrically methylated CpGs. MBD has negligable non-specific affinity for DNA, confirming that non-specific and methyl-CpG specific binding domains of MeCP2 are distinct. In vitro footprinting indicates that MBD binding can protect a 12 nucleotide region surrounding a methyl-CpG pair, with an approximate dissociation constant of 10(-9) M.

Transcriptional repression by methylation of CpG

Methylated DNA in mammals is associated with transcriptional repression and nuclease resistant chromatin. In this review we discuss how these effects may be mediated by proteins that bind to methylated DNA.