A formyl peptide receptor agonist suppresses inflammation and bone damage in arthritis

BACKGROUND AND PURPOSE

Annexin A1 (AnxA1) is an endogenous anti-inflammatory protein and agonist of the formyl peptide receptor 2 (FPR2). However, the potential for therapeutic FPR ligands to modify immune-mediated disease has been little explored. We investigated the effects of a synthetic FPR agonist on joint disease in the K/BxN model of rheumatoid arthritis (RA) and RA fibroblast-like synoviocytes (FLS).

EXPERIMENTAL APPROACH

Arthritis was induced by injection of K/BxN serum at day 0 and 2 in wild-type (WT) or AnxA1(-/-) mice and clinical and histopathological manifestations measured 8-11 days later. WT mice were given the FPR agonist compound 43 (Cpd43) (6 or 30 mg·kg(-1) i.p.) for 4 days. Effects of AnxA1 and Cpd43 on RANKL-induced osteoclastogenesis were assessed in RAW 264.7 cells and human RA FLS and macrophages.

KEY RESULTS

Treatment with Cpd43 before or after the onset of arthritis reduced clinical disease severity and attenuated synovial TNF-α and osteoclast-associated gene expression. Deletion of AnxA1 in mice exacerbated arthritis severity in the K/BxN model. In vitro, Cpd43 suppressed osteoclastogenesis and NFAT activity elicited by RANKL, and inhibited IL-6 secretion by mouse macrophages. In human RA joint-derived FLS and monocyte-derived macrophages, Cpd43 treatment inhibited IL-6 release, while blocking FPR2 or silencing AnxA1 increased this release.

CONCLUSIONS AND IMPLICATIONS

The FPR agonist Cpd43 reduced osteoclastogenesis and inflammation in a mouse model of RA and exhibited anti-inflammatory effects in relevant human cells. These data suggest that FPR ligands may represent novel therapeutic agents capable of ameliorating inflammation and bone damage in RA.

Third-party tolerogenic dendritic cells reduce allo-reactivity in vitro and ameliorate the severity of acute graft-versus-host disease in allo-bone marrow transplantation

Tolerogenic dendritic cells (tDCs) potently induce and maintain tolerance based on their distinct characteristics compared with conventional DCs. Recent reports show that donor or host tDCs promote allograft survival in mice. In this study, the efficacy of third-party tDCs in the prevention of acute graft-versus-host disease (aGVHD) was evaluated. In vitro, tDCs derived from the bone marrow (BM) of D1 mice were induced by GM-CSF, IL-10 and TGF-β1. The phenotypes, expression of cytokines and suppression of tDCs were analysed. In vivo, the effects of adoptive transfer of third-party-tDCs were evaluated in an MHC-mismatched aGVHD mouse model. Survival, body weight, GVHD scoring, histopathological specimens and serum cytokines were analysed in tDC-treated mice and untreated controls. Tolerogenic DCs had low expression of MHC and co-stimulatory molecules, expressed high levels of 'immunosuppressive' cytokines and suppressed allo-CD4(+) T cell proliferation. In the B6→D2 mouse model, all aGVHD mice died within 18 days. Fortunately, third-party tDCs transferred at low doses (10(4)) effectively prolonged survival after allo-BMT. Furthermore, in the mice treated with 10(4) tDCs, serum levels of IL-10/TGF-β were significantly higher and the percentage of Foxp3(+) cells continually increased compared with the mice treated with other doses of tDCs. Third-party tDCs play a crucial role in reducing the severity of aGVHD by modulating the secretion of various cytokines and expanding Foxp3(+) regulatory T cells, which suggests the possibility of using third-party tDCs for therapeutic applications. Furthermore, special attention should be paid to the optimal range of tDCs for preventing allograft rejection.

Comparative Modeling of Drug Target Proteins☆

In this perspective, we begin by describing the comparative protein structure modeling technique and the accuracy of the corresponding models. We then discuss the significant role that comparative prediction plays in drug discovery. We focus on virtual ligand screening against comparative models and illustrate the state-of-the-art by a number of specific examples.

Genetic analysis of the TBX2 gene promoter in indirect inguinal hernia

PURPOSE

Inguinal hernia is a common disease, majority of which are indirect inguinal hernia (IIH). A positive family history indicates that genetic factors play important roles in the IIH development. To date, genetic causes for IIH remain unknown. T-box transcription factor 2 (TBX2) is a major regulator in the morphogenesis and organogenesis. The human TBX2 gene is widely expressed in fetal and adult tissues, including muscle and connective tissues. Therefore, we speculated that altered TBX2 gene expression may be involved in the IIH formation.

METHODS

IIH patients (n = 129) and ethnic-matched healthy subjects (n = 198) were recruited for this study. The human TBX2 gene promoters were generated with PCR and directly sequenced to identify DNA sequence variants (DSVs). Furthermore, biological functions of the DSVs were examined with reporter gene constructs in cultured cells.

RESULTS

Total six DSVs within the TBX2 gene promoter were identified. A heterozygous DSV (g.59476307G>C) was identified in an IIH patient, but in none of controls, which significantly decreased the TBX2 gene promoter activities. Another heterozygous DSV (g.59476704G>C) was only found in one control, which did not affect TBX2 gene promoter activities. Four DSVs, g.59476316C>A (rs73991913), g.59476415T>C (rs1476781), g.59476510G>C (rs4455026) and g.59476892C>T (rs2286524), all of which were single nucleotide polymorphisms, were found in both IIH patients and controls with similar frequencies.

CONCLUSIONS

Our data suggested that the DSV within the TBX2 gene promoter was implicated in the IIH development as a rare cause.

On the roles of dopants in LiF:Mg,Cu,Si thermoluminescent material

The 3D thermoluminescent spectra and glow curves of LiF:Mg,Cu,Si with various Mg, Cu and Si concentrations were measured. The shapes of the glow curves in LiF:Mg,Cu,Si, LiF:Mg,Cu and LiF:Mg,Si are similar and the glow curves have peaks at approximately the same temperatures, but with significantly different intensities. Neither the temperature of the glow peak nor the wavelength of the emission maximum changes with variation of dopants concentrations when Cu is more than 0.01 mol % in LiF:Mg,Cu,Si. The spectrum structure in LiF:Mg,Cu,Si, LiF:Mg,Cu and LiF:Mg,Si is similar in the 300-550 nm range. Some weak emissions around 610 nm are shown in LiF:Mg,Cu,Si with a Cu concentration of 0.01 mol % and in LiF:Mg,Si. It is concluded that Mg dopant mainly plays a role in the formation of trapping centres, both Cu and Si play a role in the main emission process and Cu also plays a role in reducing the emission around 610 nm.

Bioinformatics analyses combined microarray identify the desregulated microRNAs in lung cancer

BACKGROUND

MicroRNAs (miRNAs) play an important role in the regulation of cell growth, differentiation, apoptosis, and carcinogenesis. Deregulated miRNAs are found in blood cells of cancer patients recently.

AIM

This study aims to screen the differentially expressed miRNAs (DE-miRNAs) which could discriminate lung cancers from non-cancerous lung tissues as well as molecular signatures that differ in tumor histology.

MATERIALS AND METHODS

miRNA expression profiles of GSE17681 was downloaded from Gene Expression Omnibus database. Three test methods were used to identify DE-miRNAs between lung cancer tissue and healthy controls. Target genes of DE-miRNAs were retrieved from three databases and mapped to KEGG to investigate their roles in lung cancer. Further, a protein-protein interaction (PPI) network was constructed used STRING and Cytoscape.

RESULTS

A total of 17 DE-miRNAs were identified. Among them, hsa-miR-339-5p draw specific attention. Pathway analysis revealed that target genes of RASSF1 and KRAS play roles as oncogene or tumor suppressor gene in the progression of lung cancer. Besides, Target genes of RASSF1 and ERBB4 formed a module in the PPI network. Functional analysis suggested biological process of response to hypoxia was significantly enriched.

CONCLUSIONS

hsa-miR-339-5p play important role in the regulation of lung cancer and it may be potential to be used as biomarker to predict lung cancer progression.

Acinetobacter baumannii isolates associated with community-acquired pneumonia in West China

Acinetobacter baumannii has emerged as an important cause of community-acquired infection. To characterize the microbiological and genotypic features of community-associated Acinetobacter baumannii, 32 isolates associated with community-acquired pneumonia were collected. These isolates were diverse in resistance patterns and had multiple clonal origins. bla(OXA-23) was the main acquired oxacillinases-encoding gene detected.

Polymorphisms in the SLC11A1 gene and tuberculosis risk: a meta-analysis update

BACKGROUND

Polymorphisms in SLC11A1 gene have been extensively studied for an association with tuberculosis (TB); however, results from replication studies have been inconsistent.

OBJECTIVE

To comprehensively evaluate the genetic risk of polymorphisms (D543N, 3'UTR TGTG ins/del, INT4, [GT]n) in the SLC11A1 gene for TB.

METHODS

A meta-analysis was carried out to analyse the association between SLC11A1 polymorphisms and TB risk.

RESULTS

A total of 82 case-control studies in 35 articles were included in the meta-analysis. The results showed that these four polymorphisms were associated with an increased risk of TB (D543N OR 1.31, 95%CI 1.11-1.55; 3'UTR TGTG ins/del OR 1.45, 95%CI 1.25-1.68; INT4 OR 1.27, 95%CI 1.09-1.49; [GT]n OR 1.35, 95%CI 1.14-1.61). In further stratified analyses by ethnicity and TB forms, significant increased risks were found in subgroups of Asians and in pulmonary TB (PTB) for all four polymorphisms, while an increased risk of extra-pulmonary TB (EPTB) was found for D543N polymorphism.

CONCLUSIONS

This meta-analysis suggests that polymorphisms in the SLC11A1 gene contribute to TB (both PTB and EPTB), particularly in Asians.

CD28 superagonist antibody treatment attenuated obliterative bronchiolitis in rat allo-orthotopic tracheal transplantation by preferentially expanding Foxp3-expressing regulatory T cells

Obliterative airway disease (OAD) due to chronic alloantigen rejection remains a major challenge for long-term graft survival in lung transplantation. It is known that superagonistic CD28-specific monoclonal antibody JJ316 (supCD28 MAb) has the ability to induce regulatory T cells (Tregs) efficiently. Here we used a rat orthotopic tracheal transplantation model to investigate the effects of supCD28 MAb on expanding Tregs in vivo and its application in suppression of acute and chronic airway allograft rejection. SupCD28 MAb administration revealed a significant increase in the CD4+CD25+ T cells, CD4+FoxP3+ T cells, and CD4+CD25+ FoxP3+ T cells population among CD4+ T cells in spleen, peripheral blood, as well as cervical lymph nodes. The allografts from animals treated with supCD28 MAb showed significantly less airway obliteration and rejection of the respiratory epithelium compared with allografts of the mouse immunoglobulin G-treated group on the 5th day and the 60th day after transplantation. Overall, our data demonstrated that an intraperitoneally administrated low dose of supCD28 MAb was sufficient to induce Treg cell expansion in vivo and was effective in protecting the airway graft from early rejection and chronic OAD development. These findings provide the basis for new therapies to prevent OAD and perhaps rejection of allografts in other human transplantations.

MTSS1, a novel target of DNA methyltransferase 3B, functions as a tumor suppressor in hepatocellular carcinoma

DNA methyltransferase 3B (DNMT3B) mediates gene silencing via epigenetic mechanisms during hepatocellular carcinoma (HCC) progression. We aimed to identify novel targets of DNMT3B and their potential regulatory mechanisms in HCC. Metastasis suppressor 1 (MTSS1) was one of the DNMT3B targets and selected for further study. DNMT3B overexpression was detected in 81.25% of clinical HCC specimens and was negatively associated with MTSS1 in HCC cells and clinical samples. The underlying mechanism by which DNMT3B silences MTSS1 was studied using a combination of methylation-specific polymerase chain reaction (PCR) and bisulfite genome sequencing, chromatin immunoprecipitation-PCR and luciferase reporter assays. We found that the MTSS1 promoter region was sparsely methylated, and the methylation inhibitors failed to abolish DNMT3B-mediated MTSS1 silencing. DNMT3B protein bound directly to the 5'-flanking region (-865/-645) of the MTSS1 gene to inhibit its transcription. The functional role of MTSS1 was investigated using in vitro and in vivo tumorigenicity assays. As a result, MTSS1 exerted tumor suppressor effects and arrested cells in the G2/M phase, but not the G1/S phase of the cell cycle when it was depleted or overexpressed in HCC cells. Taken together, MTSS1, a novel target of DNMT3B, is repressed by DNMT3B via a DNA methylation-independent mechanism. MTSS1 was further characterized as a novel tumor suppressor gene in HCC. These findings highlight how DNMT3B regulates MTSS1, and such data may be useful for the development of new treatment options for HCC.

Three synaptic components contributing to robust network synchronization

Robust synchronized activity is widely observed in real neural systems. However, a mechanism for robust synchronization that can be understood analytically, and has a clear physical meaning, remains elusive. This paper considers such a mechanism by formalizing three synaptic components contributing to robust synchronization in networks with heterogeneous external drive currents and conductance-based synapses. The first component arises from the assumption that the aggregate post-synaptic potential of a neuron decays more if it fires later within a spike volley. The second component results because neurons with smaller drives have reached a lower membrane potential at the time when the volley of inputs arrives than that reached by neurons with larger drives. The third component arises from the assumption that neurons firing later in the previous volley have had less time to integrate their drives than neurons firing earlier have had, again causing a lower membrane potential at the time when the volley of inputs arrives. Because of the voltage-dependent properties of synaptic currents, either of the last two components will cause smaller inhibitions for the later-firing neurons if the synapses are inhibitory. This smaller inhibition causes the later-firing neurons to fire earlier in the next cycle, thereby forcing them toward synchrony. With these three synaptic components, we discuss the relationship between the robustness of the synchrony and the parameters, search for the optimal parameter set for the robust network synchronization of a certain frequency band, and demonstrate the key role of the voltage-dependent properties of synaptic currents in robust or stable synchronization.

The I/D polymorphism of angiotensin-converting enzyme gene and asthma risk: a meta-analysis

BACKGROUND

  The insertion/deletion (I/D) polymorphism of angiotensin-converting enzyme (ACE) gene has been implicated in susceptibility to asthma, but a large number of studies have reported inconclusive results. The aim of this study is to investigate the association between the I/D polymorphism of ACE gene and asthma risk by meta-analysis.

METHODS

  We searched Medline (Ovid), Pubmed, CNKI, Wanfang, and Weipu database, covering all papers until March 12, 2010. Statistical analysis was performed by using the software revman 4.2 (The Cochrane Collaboration, http://www.cochrane.org) and stata 10.0 (StataCorp, College Station, TX, USA, http://www.stata.com).

RESULTS

  A total of 1946 cases and 2152 controls in 18 case-control studies were included in this meta-analysis. The results indicated that the DD homozygote carriers had a 59% increased risk of asthma, when compared with the homozygotes II and heterozygote DI [odds ratio (OR)=1.59, 95% confidence interval (CI): 1.16-2.18]. In the subgroup analysis by ethnicity, significant elevated risks were associated with DD homozygote carriers in Asians (OR=2.02 and 95% CI: 1.29-3.16 for DD vs DI+II) but not in Caucasians (OR=1.14 and 95% CI: 0.76-1.72 for DD vs DI+II). In the subgroup analysis by age, significant elevated risks were associated with DD homozygote carriers in children (OR=2.44 and 95% CI: 1.36-4.38 for DD vs II+DI) but not in adults (OR=1.54 and 95% CI: 0.94-2.51 for DD vs II+DI).

CONCLUSIONS

  This meta-analysis suggested that the I/D polymorphism of ACE gene would be a risk factor of asthma. To further evaluate gene-to-gene and gene-to-environment interactions between polymorphisms of ACE gene and asthma risk, more studies with large groups of patients are required.

Abstract P1-02-07: Real-Time Functional Imaging of Tumor Vascular Normalization by Anti-Angiogenic Agents

Background: We describe here new technology that enables non-invasive imaging of normalization of tumor blood vessels by anti-angiogenic agents in real time.

Materials and Methods: Variable-magnification in vivo-fluorescence imaging as well as fluorescence tomography were used to visualize vessel normalization.

Results: Morphological changes in the same vessel prior to and after drug treatment were imaged with high resolution in real time. Differences in vascular responses to the mTOR inhibitor rapamycin and to an anti-VEGF antibody were functionally imaged. Tumor vessel normalization was demonstrated by significantly reduced leakiness and subsequent improved tumor delivery of Paclitaxel-BODPY as well as by normalized morphology. The tumor vascular pool agent, AngioSense750, was retained in tumors after both anti-VEGF antibody and rapamycin treatment as visualized by noninvasive fluorescence tomography. The anti-angiogenic therapy normalized vessels, which significantly enhanced the antitumor efficacy of Paclitaxel due to increased drug penetration throughout the tumor. Discussion: The optical imaging technology described here is thus a powerful real-tool imaging tool of functional and morphological tumor vessel normalization and its therapeutic consequences.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-02-07.

Hypothalamus syndrome in opticospinal multiple sclerosis

This study describes a case of a patient with OSMS who presented with somnolence, periodic fever, memory impairment, and amenorrhea. Serum prolactin levels were found to be higher than normal. MR imaging showed a bilateral involvement of the hypothalamus. The clinical presentation, laboratory examination, and MR imaging findings suggested a diagnosis of hypothalamus syndrome in this patient.

Discovery of SNP in exon 14 of the <i>ADD1</i> gene and its association with fatness traits in four meat-type duck populations (Brief Report)

Abstract. Fatness traits are important economically traits in meat producing animals including duck (WU et al. 2008a, b). In human, the α-Adducin (ADD1) gene polymorphism was associated with blood pressure and other subsequent negative effects related to obesity, cardiovascular and renal failure. In fact, there was some relationship between obesity and hypertension. Thus the ADD1 gene is a candidate gene for fatness traits and the study aims to invest the relationship between the polymorphism of the ADD1 gene and fatness and growth traits.

Induction of subcutaneous adipose proliferation by olanzapine in rodents

Weight gain induced by atypical antipsychotics causes a serious health concern in the treatment of schizophrenic patients. In the present study chronic treatment of female Wistar rats with olanzapine caused weight gain, but limited effect on food intake. A dramatic drug-induced morphological change of the subcutaneous adipose tissue was observed, i.e. development of a pinkish coloration with the appearance of a "fish egg"-like texture. Histological examination revealed a massive increase in the proliferation of undifferentiated adipocytes. Such proliferation was detected as early as the third day after olanzapine treatment. The changes progressed in a time- and dose-dependent manner. The proliferation of adipose tissue was detected in rats treated with olanzapine independent of increases in weight gain. Protein profiles of the adipose tissue were also altered by olanzapine. These results suggest that olanzapine-induced weight gain may be not solely due to an effect on behavioural satiety. The potential involvement of adipose neuronal input and proliferation are discussed.

Postural epigastric pain as a sign of cytomegalovirus gastritis in renal transplant recipients: a case-based review

BACKGROUND

Cytomegalovirus (CMV) infection is a common cause of morbidity and mortality among patients receiving chronic maintenance immunosuppression and is often considered the most important infection in renal transplantation. CMV gastritis has been reported in transplant recipients. Symptoms are usually considered nonspecific, and gastroscopy with biopsy is usually performed to establish the diagnosis.

METHODS

We report a case of primary CMV gastritis in a renal transplant recipient. A 34-year-old man presented 4 months after renal transplantation with a 1-week history of epigastric pain that decreased in supine position, increased while sitting, and further increased when standing or walking. The immunosuppressive regimen consisted of tacrolimus, mycophenolate mofetil, and prednisone. Evaluation revealed CMV viremia with a high viral load and CMV gastritis was confirmed using gastroscopy and histopathologic examination. Intravenous ganciclovir was started and continued for 3 weeks. The epigastric pain completely resolved after treatment with ganciclovir.

CONCLUSIONS

Postural epigastric pain as a sign of CMV gastritis is fairly rare in renal transplant recipients. To our knowledge this is the third article presented in the literature so far.

A phospholipid-PEG2000 conjugate of a vascular endothelial growth factor receptor 2 (VEGFR2)-targeting heterodimer peptide for contrast-enhanced ultrasound imaging of angiogenesis

The transition of a targeted ultrasound contrast agent from animal imaging to testing in clinical studies requires considerable chemical development. The nature of the construct changes from an agent that is chemically attached to microbubbles to one where the targeting group is coupled to a phospholipid, for direct incorporation to the bubble surface. We provide an efficient method to attach a heterodimeric peptide to a pegylated phospholipid and show that the resulting construct retains nanomolar affinity for its target, vascular endothelial growth factor receptor 2 (VEGFR2), for both the human (kinase insert domain-containing receptor - KDR) and the mouse (fetal liver kinase 1 - Flk-1) receptors. The purified phospholipid-PEG-peptide isolated from TFA-based eluents is not stable with respect to hydrolysis of the fatty ester moieties. This leads to the time-dependent formation of the lysophospholipid and the phosphoglycerylamide derived from the degradation of the product. Purification of the product using neutral eluent systems provides a stable product. Methods to prepare the lysophospholipid (hydrolysis product) are also included. Biacore binding data demonstrated the retention of binding of the lipopeptide to the KDR receptor. The phospholipid-PEG2000-peptide is smoothly incorporated into gas-filled microbubbles and provides imaging of angiogenesis in a rat tumor model.

Visual computing in electron crystallography

VEC is a program package for Visual computing in Electron Crystallography. The program is written mainly in C++ and Fortran and is for running under MS Windows 95, 98, NT and 2000. Apart from its user-friendly interface, sophisticated text-sensitive online helps and tutorials, VEC includes same unique crystallographic methods. They are direct-method image-processing techniques, ab-initio solution of incommensurate crystal structures and algorithms for searching one-dimensionally modulated atoms in 4-dimensional Fourier maps. Examples are given in details.

The effect of clomipramine on wake/sleep and orexinergic expression in rats

We have previously found that neonatal treatment with clomipramine (CLI) induced a decrease in brain orexins during the juvenile period and that these changes were reversed at adulthood. This study investigated the effect of CLI on the orexinergic component and sleep/wake states. Two groups of adult male rats were conducted for 48-h polysomnographic recording. One group of rats was treated with CLI (20 mg/kg every 12 h), and a second group was treated with equivolume of saline (SAL) simultaneously after the first 24 h of polysomnographic recording. Rats were killed 2 h after the third dose of treatment. Brain tissues were collected for radioimmunoassay quantification of orexins and real-time PCR analysis of prepro-orexin and orexin receptor mRNA. The CLI group had significantly shorter rapid eye movement (REM) sleep and longer REM latency compared with both the baseline day and the SAL group and had significantly less active wake and more quiet wake. Compared with the control rats, the CLI rats had significantly higher mRNA expression of prepro-orexin in the hypothalamus and the frontal cortex, but not in the hippocampus. The CLI rats also had significantly less orexin B in the hypothalamus than the control rats. These results suggest that suppression of active wake and orexin B by CLI may be a factor responsible for CLI-induced depression and that the increase of prepro-orexin mRNA may be a sign of increased brain orexins found in this model.

Plasma ghrelin levels and weight loss in Chinese Uygur patients with chronic obstructive pulmonary disease

Ghrelin is an important orexigenic hormone that reduces fat oxidation and increases adiposity. This study investigated plasma ghrelin levels in Chinese Uygur patients with chronic obstructive pulmonary disease (COPD). Plasma ghrelin and anabolic and catabolic factors were measured in 38 patients and 24 control subjects. COPD patients were divided into two groups based on body mass index (BMI): underweight (BMI < 20 kg/m(2), n = 18) or normoweight (BMI > or = 20 kg/m(2), n = 20). Plasma ghrelin levels were found to be significantly higher in underweight than in normoweight patients or healthy controls. Circulating tumour necrosis factor-alpha and interleukin-6 concentrations were significantly higher in underweight than in normoweight patients, whereas insulin concentrations were significantly lower. Plasma ghrelin levels correlated negatively with forced expiratory volume in 1 s (FEV(1); r = 0.35), but did not significantly correlate with FEV(1)/forced vital capacity. Plasma ghrelin levels were elevated in underweight COPD patients and were associated with cachexia and abnormal pulmonary function.

Feedback mechanism in network dynamics with preferential flow

We study complex systems or networks in which each node holds an internal dynamics and interacts with other nodes through some kinds of topologies. Collective behavior with dynamical fluctuations is analyzed in complex systems. The dynamical fluctuations of a node can be divided into two parts: one is the internal dynamical fluctuation of the node and the other is the external dynamical fluctuation caused by other nodes. Based on a theoretical analysis, a hidden feedback mechanism is identified in complex systems, which is illustrated in a macroeconomic network and in a city-population network. Furthermore, we study the effect of the topology of the networks on the feedback mechanism. The feedback mechanism is preserved for hub nodes in the networks with a scale-free topology as well as in the networks with an evolving topology. By the hidden feedback mechanism, the observation data can be utilized to judge directly whether the system of each node is with positive feedback or with negative feedback even without knowing its dynamical model.

Multicommunity weight-driven bipartite network model

Community structure and rewiring phenomena exist in many complex networks, particularly in bipartite networks. We construct a model for the degree distribution of the rewiring problem in a multicommunity weight-driven bipartite network (MCWBN). The network consists of many interconnected communities, each of which holds a bipartite graph. The bipartite graph consists of two sets of nodes. We name each node in one set a "producer" and each node in the other set a "consumer." A weight value matrix defining the trade barrier between any two communities is used to characterize the structure of the communities, which ensures the higher preferential attachment probability in intracommunity than in intercommunity. The size of one producer is defined as the number of consumers connected to it. We find that the nonlinear dynamics of the scale of production, or the total size of all producers in each community is dependent only on the initial scale of production in each community, and independent of the distribution of the producer size. Furthermore, if the nonlinear system of the scale of production in each community is at an equilibrium state, the distribution of the producer size in each community of the MCWBN model is equivalent to that in a one-community model.