Highly Aromatic Norditerpenoid Heterodimers and Monomers from Trigonostemon fragilis

Four new norditerpenoid heterodimers with different dimerization patterns-namely,trigofragiloids A-C(denoted as compounds 1-3)and(+)-and(-)-trigofragiloid D(compound 4)-and three new phenanthrenone norditerpenoids-namely,trigofragiloids E-G(compounds 5-7)-were isolated from Trigonostemon fragilis.Compounds 1 and 2 feature a novel heterodimeric carbon skeleton formed by the conjugation of a tetra-norditerpenoid and an ennea-norditerpenoid;they have been identified as class 2 atropisomers by means of quantum chemical calculations.Compound 3 is an unprecedented phenylpropanoid-norditerpenoid adduct with a new dimerization pattern.Compounds(+)-and(-)-4 are the first example of S-shaped 1,4-dioxane-fused norditerpenoid dimers.Inspired by the structure elucidation of compound 4,two co-occurring analogues,actephilol A and epiactephilol A,were structurally revised as a pair of geometrical isomers and were identified as two pairs of enantiomers,(+)-and(-)-8 and(+)-and(-)-9,respectively.Their structures were characterized using a combined method.Notably,compound 7 exhibits remarkable adenosine triphosphate-citrate lyase(ACLY)inhibition with a halfmaximal inhibition concentration(IC50)value of(0.46±0.11)lmol·L^(-1),as active as the positive control BMS-303141,and a molecular docking study offers deep insight into the interaction between compound 7 and ACLY.

DNA end binding activity and Ku70/80 heterodimer expression in human colorectal tumor

AIM： TO determine the DNA binding activity and protein levels of the Ku70/80 heterodimer, the functional mediator of the NHEJ activity, in human colorectal carcinogenesis. METHODS： The Ku70/80 DNA-binding activity was determined by electrophoretic mobility shift assays in 20 colon adenoma and 15 colorectal cancer samples as well as matched normal colonic tissues. Nuclear and cytoplasmic protein expression was determined by immunohistochemistry and Western blot analysis. RESULTS： A statistical found in both adenomas y significant difference was and carcinomas as compared to matched normal colonic mucosa （P〈0.00）. However, changes in binding activity were not homogenous with approximately 50% of the tumors showing a clear increase in the binding activity, 30% displaying a modest increase and 15% showing a decrease of the activity.Tumors, with increased DNA-binding activity, also showed a statistically significant increase in Ku70 and Ku86 nuclear expression, as determined by Western blot and immunohistochemical analyses （P〈0.001）. Cytoplasmic protein expression was found in pathological samples, but not in normal tissues either from tumor patients or from healthy subjects. CONCLUSION： Overall, our DNA-binding activity and protein level are consistent with a substantial activation of the NHEJ pathway in colorectal tumors. Since the NHEJ is an error prone mechanism, its abnormal activation can result in chromosomal instability and ultimately lead to tumorigenesis.

Structure of Protonated Heterodimer of Proline and Phenylalanine:Revealed by Infrared Multiphoton Dissociation Spectroscopy and Theoretical Calculations

The infrared multiphoton dissociation(IRMPD)spectrum of the protonated heterodimer of Pro Phe H+,in the range of 2700-3700 cm^-1,has been obtained with a Fourier-transform ion cyclotron mass spectrometer combined with an IR OPO laser.The experimental spectrum shows one peak at 3565 cm^-1 corresponding to the free carboxyl O-H stretching vibration,and two broad peaks centered at 2935 and 3195 cm^-1.Theoretical calculations were performed on the level of M062 X/6-311++G(d,p).Results show that the most stable isomer is characterized by a charge-solvated structure in which the proton is bound to the unit of proline.Its predicted spectrum is in good agreement with the experimental one,although the coexistence of salt-bridged structures cannot be entirely excluded.

The heterodimeric structure of heterogeneous nuclear ribonucleoprotein C1/C2 dictates 1,25-dihydroxyvitamin D-directed transcriptional events in osteoblasts

Heterogeneous nuclear ribonucleoprotein （hnRNP） C plays a key role in RNA processing but also exerts a dominant negative effect on responses to 1,25-dihydroxyvitamin D （1,25（OH）2D） by functioning as a vitamin D response element-binding protein （VDRE-BP）. hnRNPC acts a tetramer of hnRNPC1 （huC1） and hnRNPC2 （huC2）, and organization of these subunits is critical to in vivo nucleic acid-binding. Overexpression of either huC1 or huC2 in human osteoblasts is sufficient to confer VDRE-BP suppression of 1,25（OH）2D-mediated transcription. However, huC1 or huC2 alone did not suppress 1,25（OH）2D-induced transcription in mouse osteoblastic cells. By contrast, overexpression of huC1 and huC2 in combination or transfection with a bone-specific polycistronic vector using a ＂self-cleaving＂ 2A peptide to co-express huC1/C2 suppressed 1,25D-mediated induction of osteoblast target gene expression. Structural diversity of hnRNPC between human/NWPs and mouse/rat/rabbit/dog was investigated by analysis of sequence variations within the hnRNP CLZ domain. The predicted loss of distal helical function in hnRNPC from lower species provides an explanation for the altered interaction between huC1/C2 and their mouse counterparts. These data provide new evidence of a role for hnRNPC1/C2 in 1,25（OH）2D-driven gene expression, and further suggest that species-specific tetramerization is a crucial determinant of its actions as a regulator of VDR-directed transactivation.

Identification of a Native Novel Oncolytic Immunoglobulin on Exfoliated Colon Epithelial Cells: A Bispecific Heterodimeric Chimera of IgA/IgG*

Understanding the nature of cell surface markers on exfoliated colonic cells is a crucial step in establishing criteria for a normally functioning mucosa. We have found that colonic cells isolated from stool samples (SCSR-010 Fecal Cell Isolation Kit, NonInvasive Technologies, Elkridge, MD), preserved at room temperature for up to one week, with viability of >85% and low levels of apoptosis (8% - 10%) exhibit two distinct cell size subpopulations, in the 2.5 μM - 5.0 μM and 5.0 μM - 8.0 μM range. In addition to IgA, about 60% of the cells expressed a novel heterodimeric IgA/IgG immunoglobulin that conferred a broad-spectrum cell mediated cytotoxicity against tumor cells. In a cohort of 58 subjects the exclusive absence of this immunoglobulin in two African-Americans was suggestive of a germline deletion. Serial cultures in stem cell medium retained the expression of this heterodimer. Since a majority of the cystic cells expressed the stem cell markers Lgr5 and Musashi-1 we termed these cells as gastrointestinal progenitor stem cells (GIP-C**). CXCR-4, the cytokine co-receptor for HIV was markedly expressed. These cells also expressed CD20, IgA, IgG, CD45, and COX-2. We assume that they originated from mature columnar epithelium by dedifferentiation. Our observations indicate that we have a robust noninvasive method to study mucosal pathophysiology and a direct method to create a database for applications in regenerative medicine.

Synthesis and properties of Au-Fe_3O_4 and Ag-Fe_3O_4 heterodimeric nanoparticles

Monodisperse Au-Fe3O4 heterodimeric nanoparticles （NPs） were prepared by injecting precursors into a hot reaction solution. The size of Au and Fe3O4 particles can be controlled by changing the injection temperature. UVis spectra show that the surface plasma resonance band of Au-Fe3O4 heterodimeric NPs was evidently red-shifted compared with the resonance band of Au NPs of similar size. The as-prepared heterodimeric Au-Fe3O4 NPs exhibited superparamagnetic properties at room temperature. The Ag-Fe3O4 heterodimeric NPs were also prepared by this synthetic method simply using AgNO3 as precursor instead of HAuCl4. It is indicated that the reported method can be readily extended to the synthesis of other noble metal conjugated heterodimeric NPs.

Role of opioid receptor heterodimerization in pain modulation and tolerance development

Protein to protein interactions leading to homo/heteromerization of receptor is well documented in literature. These interactions leading to dimeric/oligomers formation of receptors are known to modulate their function, particularly in case of G-protein coupled receptors. The opioid receptor heteromers having changed pharmacological properties than the constituent protomers provides preferences for novel drug targets that could lead to potential analgesicactivity devoid of tolerance and physical dependence. Heterodimerization of opioid receptors appears to generate novel binding properties with improved specificity and lack of side effects. Further the molecules which can interact simultaneously to both the protomers of the heteromer, or to both the binding sites(orthosteric and allosteric) of a receptor protein could be potential therapeutic molecules. This review highlights the recent advancements in exploring the plausible role of heteromerization of opioid receptors in induction of tolerance free antinociception.

Src heterodimerically activates Lyn or Fyn to serve as targets for the diagnosis and treatment of esophageal squamous cell carcinoma

Although Src is one of the oldest and most investigated oncoproteins,its function in tumor malignancy remains to be defined further.In this study,we demonstrated that the inhibition of Src activity by ponatinib effectively suppressed several malignant phenotypes of esophageal squamous cell carcinoma(ESCC)both in vitro and in vivo,whereas it did not produce growthinhibitory effects on normal esophageal epithelial cells(NEECs).Importantly,we combined phosphoproteomics and several cellular and molecular biologic strategies to identify that Src interacted with the members of Src-family kinases(SFKs),such as Fyn or Lyn,to form heterodimers.Src interactions with Fyn and Lyn phosphorylated the tyrosine sites in SH2(Fyn Tyr^(185)or Lyn Tyr^(183))and kinase domains(Fyn Tyr^(420) or Lyn Tyr^(397)),which critically contributed to ESCC development.By contrast,Src could not form heterodimers with Fyn or Lyn in NEECs.We used RNA sequencing to comprehensively demonstrate that the inhibition of Src activity effectively blocked several critical tumor-promoting pathways,such as JAK/STAT,mTOR,stemness-related,and metabolism-related pathways.Results of the real-time polymerase chain reaction(RT-PCR)assay confirmed that Lyn and Fyn were critical effectors for the Src-mediated expression of tumor growth or metastasis-related molecules.Furthermore,results of the clinical ESCC samples showed that the hyperactivation of pSrc Tyr^(419),Fyn Tyr^(185) or Tyr^(420),and Lyn Tyr^(183)or Tyr^(397)could be biomarkers of ESCC prognosis.This study illustrates that Src/Fyn and Src/Lyn heterodimers serve as targets for the treatment of ESCC.

Metformin:A promising clinical therapeutical approach for BPH treatment via inhibiting dysregulated steroid hormones-induced prostatic epithelial cells proliferation

The occurrence of benign prostate hyperplasia(BPH)was related to disrupted sex steroid hormones,and metformin(Met)had a clinical response to sex steroid hormone-related gynaecological disease.However,whether Met exerts an antiproliferative effect on BPH via sex steroid hormones remains unclear.Here,our clinical study showed that along with prostatic epithelial cell(PEC)proliferation,sex steroid hormones were dysregulated in the serum and prostate of BPH patients.As the major contributor to dysregulated sex steroid hormones,elevated dihydrotestosterone(DHT)had a significant positive relationship with the clinical characteristics of BPH patients.Activation of adenosine 5'-monophosphate(AMP)-activated protein kinase(AMPK)by Met restored dysregulated sex steroid hormone homeostasis and exerted antiproliferative effects against DHT-induced proliferation by inhibiting the formation of androgen receptor(AR)-mediated Yes-associated protein(YAP1)-TEA domain transcription factor(TEAD4)heterodimers.Met’s anti-proliferative effects were blocked by AMPK inhibitor or YAP1 overexpression in DHT-cultured BPH-1 cells.Our findings indicated that Met would be a promising clinical therapeutic approach for BPH by inhibiting dysregulated steroid hormone-induced PEC proliferation.

The dopaminergic system and Alzheimer's disease

Alzheimer's disease is a common neurodegenerative disorder in older adults.Despite its prevalence,its pathogenesis remains unclea r.In addition to the most widely accepted causes,which in clude excessive amyloid-beta aggregation,tau hyperphosphorylation,and deficiency of the neurotransmitter acetylcholine,numerous studies have shown that the dopaminergic system is also closely associated with the occurrence and development of this condition.Dopamine is a crucial catecholaminergic neurotransmitter in the human body.Dopamine-associated treatments,such as drugs that target dopamine receptor D and dopamine analogs,can improve cognitive function and alleviate psychiatric symptoms as well as ameliorate other clinical manifestations.Howeve r,therapeutics targeting the dopaminergic system are associated with various adverse reactions,such as addiction and exacerbation of cognitive impairment.This review summarizes the role of the dopaminergic system in the pathology of Alzheimer's disease,focusing on currently available dopamine-based therapies for this disorder and the common side effects associated with dopamine-related drugs.The aim of this review is to provide insights into the potential connections between the dopaminergic system and Alzheimer's disease,thus helping to clarify the mechanisms underlying the condition and exploring more effective therapeutic options.

Epstein-Barr virus-encoded latent membrane protein 1 modulates cyclin D1 by c-Jun/Jun B heterodimers

In our recent studies, we found that LMP1 encoded by Epstein-Barr virus could accelerate the formation of active c-Jun/Jun B heterodimer. We studied the regulation of cyclinD1 by c-Jun/Jun B heterodimers by laser scanning confocal influorescence microscopy, Western blot, luciferase activity assay, super-EMSA and flow cytometry in the Tet-on-LMP1 HNE2 cell line, in which LMP1 expression was regulated by Tet-on system. c-Jun/Jun B heterodimers induced by LMP1 could up regulate cyclin D1 promoter activity and expression. Overexpression of cy-clinD1 accelerated the progression of cell cycle.

Heterodimer formation between c-Jun and Jun B proteins mediated by Epstein Barr virus encoded latent membrane protein 1

Epstein-Barr virus (EBV) encoded latent membrane protein 1 (LMP1) may trigger the transcription factor AP-1 including c-Jun and c-fos. In this report, using a Tet-on LMP1 HNE2 cell line which is a dual-stable LMP1 integrated nasopharyngeal carcinoma (NPC) cell line and the expression of LMP1 in which could be regulated by the Tet-on system, we show that Jun B can efficiently form a new heterodimeric complex with the c-Jun protein under the regulation of LMP1, phosphorylation of c-Jun (ser 63, ser 73) and Jun B is involved in the process of the new heterodimeric formation. We also find that this heterodimeric form can bind to the AP-1 consensus sequence. Transfection studies suggest that JNK interaction protein (JIP) could inhibit the heterodimer formation of c-Jun and Jun B through blocking the AP-1 signaling pathway triggered by LMP1. The interaction and function between c-Jun protein and Jun B protein increase the repertoire of possible regulatory complexes by LMP1 that could play an important role in the regulation of transcription of specific cellular genes in the process of genesis of nasopharyngeal carcinoma.

Recyclable magnetite-silver heterodimer nanocomposites with durable antibacterial performance

There is a significant need for magnetite-silver nanocomposites that exhibit durable and recyclable antimicrobial activity.In this study,magnetic iron oxide nanoparticles(Fe3O4 NPs)coated with ethylenediamine-modified chitosan/polyacrylic acid copolymeric layer(Fe3O4@ECS/PAA)were fabricated.Subsequently,directly deposited silver(Ag)NPs procedure was carried out to form the antibacterial heterodimers of Fe3O4@ECS/PAA-Ag NPs.The composition and morphology of the resultant nanostructures were confirmed by FT-IR,XRD,TEM and TGA.The overall length of the heterodimers was approximately 45 nm,in which the mean diameter of Fe3O4@ECS/PAA NPs reached up to 35 nm,and that of Ag NPs was around 15 nm.The mass fraction of silver NPs in the nanocomposites was about 63.1%.The obtained Fe3O4@ECS/PAA NPs exhibited good colloidal stability,and excellent response to additional magnetic field,making the NPs easy to recover after antibacterial tests.In particular,the Fe3O4@ECS/PAAAg NPs retained nearly 100%biocidal efficiency(106e107 CFU/mg nanoparticles)for both Gram-negative bacteria E.coli and Gram-positive bacteria S.aureus throughout ten cycles without washing with any solvents or water,exhibiting potent and durable antibacterial activity.

A Novel Ratiometric Oxygen Sensor Based On a Sextuple Hydrogen-Bonding Self-Assembly Molecular Heterodimer

A novel sextuple hydrogen-bonding （HB） self-assembly molecular heterodimer bearing an iridium complex as the indicator dye and two carbazoles as the reference dye, namely 6HB-Irbt-Cz, was synthesized, and its molecular structure was confirmed by ^1H NMR, ^13CNMR, TOF-MS and 2D NMR. Because of the inefficient energy transfer process between the carbazole and iridium complex units, 6HB-Irbt-Cz exhibits distinct fluorescence/ phosphorescence dual emission in neat film state. More importantly, the neat film sample of 6HB-Irbt-Cz could display linear ratiometric optical response toward oxygen in the full oxygen concentration range from 0 to 100 vol%, together with good stability, reversibility and rapid response-recovery times. Note that this represents the first discovery of neat-film-based oxygen sensor capable of showing strictly linear ratiometric Stem-Volmer behavior in the oxygen concentration of 0- 100 vol%.

Ergochaeglobosins A—E, Unprecedented Heterodimers of Cytochalasan and Ergosterol from Chaeglobosin globosum P2-2-2

Five novel heterodimers of cytochalasan and ergosterol,ergochaeglobosins A—E,were isolated from an endophytic fungus Chaetomium globosum P2-2-2.Ergochaeglobosin A(1) possesses an unprecedented 5/6/13/6/5/6/6/6 fused octacyclic ring system,and ergochaeglobosins B(2) and C(3) form a unique 5/6/13/6/6/6/6/5 fused octacyclic ring system,whereas ergochaeglobosins D(4) and F(5) are the first cytochalasan heterodimers formed via a N-1′/C-3′′single bond.Their structures with absolute configurations were established by extensive spectroscopic analyses,single-crystal X-ray diffraction,and ECD calculations.The plausible biogenetic pathway of 1—5 was postulated.Compound 1 exhibited inhibitory effects against ConA-induced T cells and LPS-induced B cells proliferation with IC50 values of 19.2 and 14.1μmol/L,respectively.Co-treatment of 3(20μmol/L)with TRAIL(150 ng/mL)could significantly decrease the cell viability of A549 by 24.9%comparing with monotherapy of 3(20μmol/L).

Self-assembly of Hydrazide-based Heterodimers Driven by Hydrogen Bonding and Donor-Acceptor Interaction

A new series of hydrogen bonding-driven heterodimers have been self-assembled in chloroform from hydrazide-based monomers. Additional intermolecular donor-acceptor interaction between the electron-rich bis（p-phenylene）-34-crown-10 unit and the electron-deficient naphthalene diimide unit has been utilized to increase the stability of the dimmers, and pronounced cooperativity of the two discrete non-covalent forces to stabilize the dimer has been revealed by the quantitative ^1H （2D） NMR and UV-Vis experiments.

Synthesis and photophysical properties of porphyrin-phthalocyanine heterodimer linked by piperazine

A porphyrin-phthalocyanine heterodimer linked by piperazine has been synthesized and characterized by spectroscopic methods. UV-visible absorption spectra indicated the presence of weak intramolecular interaction between the two chromophores. Selective excitation of the porphyrin moiety leads to energy transfer process to the phthalocyanine subunit. Furthermore, on the bases of the solvent-dependent fluorescence data, a competing electron transfer reaction is shown to occur in this heterodimer. The efficiency of both photophysical processes depends strongly on solvent polarity and is related to the separation distance of the two chromophores and their relative orientation. The value of ΔG obtained using the Rehm-Weller equation clearly indicates that the heterodimer exists preferably in the “boat form” upon excitation in good agreement with the experimental results of co-occurence of energy and electron transfer process observed for the heterodimer.

TLR4 signaling and the inhibition of liver hepcidin expression by alcohol

AIM: To understand the role of toll-like receptor 4 (TLR4) signaling in the regulation of iron-regulatory hormone, hepcidin by chronic alcohol consumption.

Abnormal DNA-PKcs and Ku 70/80 expression may promote malignant pathological processes in gastric carcinoma

AIM:To determine the expression of the catalytic subunit of DNA-dependent protein kinase(DNA-PKcs)and the Ku70/Ku80 heterodimer(Ku 70/80)in gastric carcinoma.METHODS:Gastric biopsies were obtained from 146gastric carcinoma patients[Helicobacter pylori(H.pylori)-negative:89 and H.pylori-positive:57]and 34from normal subjects(H.pylori-negative:16 and H.pylori-positive:18)via surgery and endoscopic detection from April 2011 to August 2012 at the First Affiliated Hospital of Nanchang University.Pathological diagnosis and classification were made according to the criteria of the World Health Organization and the updated Sydney system.An‘‘in-house’’rapid urease test and modified Giemsa staining were employed to detect H.pylori infection.The expression of DNA-PKcs and the Ku 70/80protein was detected by immunohistochemistry.RESULTS:Overall,the positive rates of both DNA-PKcs and Ku 70/80 were significantly increased in gastric cancer(χ2=133.04,P<0.001 for DNA-PKcs andχ2=13.06,P<0.01 for Ku)compared with normal gastric mucosa.There was hardly any detectable expression of DNA-PKcs in normal gastric mucosa,and the positive rate of DNA-PKcs protein expression in patients with a normal gastric mucosa was 0%(0/34),whereas the rate in gastric cancer(GC)was 93.8%(137/146).The difference between the two groups was statistically significant.Additionally,the positive rate of Ku 70/80 was79.4%(27/34)in normal gastric mucosa and 96.6%(141/146)in gastric cancer.The DNA-PKcs protein level was significantly increased in gastric cancer(MannWhitney U=39.00,P<0.001),compared with normal gastric mucosa.In addition,there was a significant difference in the expression of Ku 70/80(Mann-Whitney U=1117.00,P<0.001)between gastric cancer and normal gastric mucosa.There was also a significant difference in Ku70/80 protein expression between GC patients with and without H.pylori infection(P<0.05).Spearman analysis showed a negative correlation between tumor differentiation and DNA-PKcs expression(r=-0.447,P<0.05).Moreover,Ku70/80 expression was negatively correlated with both clinical stage(r=-0.189,P<0.05)and H.pylori colonization(r=-0.168,P<0.05).CONCLUSION:Overall,this research demonstrated that enhanced DNA-PKcs and Ku 70/80 expression may be closely associated with gastric carcinoma.

Carrier frequency of HLA-DQB1*02 allele in patients affected with celiac disease:A systematic review assessing the potential rationale of a targeted allelic genotyping as a first-line screening

BACKGROUND Celiac Disease(CD)is an immune-mediated disorder,in which the HLA immunogenetic background(DQ2 and DQ8 heterodimers)and environmental trigger(gluten)are well established.Indeed,both factors are necessary–but not sufficient–to develop CD.However,it is very likely that CD is underdiagnosed in both developing and developed countries,due to several aspects,including the fact that a lot of patients present mild and/or atypical symptoms,without the presence of any recognized risk factors.Therefore,the possibility and feasibility of widened screening strategies to identify CD patients are debated.AIM To provide further evidence of the main epidemiological importance of HLADQB1*02 allele in the population of CD patients.METHODS We performed a systematic search in PubMed,EMBASE,Cochrane,Web of Science and Scopus databases,in order to produce a systematic review assessing the carrier frequency of HLA-DQB1*02 allele in the celiac population.Following the PRISMA guidelines,we retrieved all the original articles describing CD patients’HLA-DQB1 genotype in such a way that could allow to assess the HLADQB1*02 carrier frequency among CD patients,along with the evidence of the appropriate diagnostic work-up to achieve a correct and final diagnosis of CD.RESULTS The final output of this systematic search in the medical literature consisted of 38 studies providing the appropriate HLA-DQB1 genotype information of the respective CD population.According to this systematic review,including a pool of 4945 HLA-DQ genotyped CD patients,the HLA-DQB1*02 carrier frequency was 94.94%,meaning that only 5.06%of CD patients were completely lacking this allelic variant.Interestingly,if we consider only the studies whereby the prevalence of CD patients affected with type 1 diabetes mellitus was supposed or clearly established to be very low,the frequency of non-HLA-DQB1*02 carriers among CD patients dropped to 3.65%.CONCLUSION Such a high carrier frequency of the HLA-DQB1*02 allelic variant(which is>95%-96%in CD patients without risk factors,like type 1 diabetes mellitus comorbidity)might be exploited to consider a cost-effective and widened screening approach.If a sustainable strategy could be implemented through a low-cost targeted genetic test to detect the individual presence of HLA-DQB1*02 allele,an appropriate algorithm for serological screening in individuals resulting to be genetically predisposed to CD,might be considered.