Loss of fibulin-2 protects against progressive ventricular dysfunction after myocardial infarction

Remodeling of the cardiac extracellular matrix (ECM) is an integral part of wound healing and ventricular adaptation after myocardial infarction (MI), but the underlying mechanisms remain incompletely understood. Fibulin-2 is an ECM protein upregulated during cardiac development and skin wound healing, yet mice lacking fibulin-2 do not display any identifiable phenotypic abnormalities. To investigate the effects of fibulin-2 deficiency on ECM remodeling after MI, we induced experimental MI by permanent coronary artery ligation in both fibulin-2 null and wild-type mice. Fibulin-2 expression was up-regulated at the infarct border zone of the wild-type mice. Acute myocardial tissue responses after MI, including inflammatory cell infiltration and ECM protein synthesis and deposition in the infarct border zone, were markedly attenuated in the fibulin-2 null mice. However, the fibulin-2 null mice had significantly better survival rate after MI compared to the wild-type mice as a result of less frequent cardiac rupture and preserved left ventricular function. Up-regulation of TGF-β signaling and ECM remodeling after MI were attenuated in both ischemic and non-ischemic myocardium of the fibulin-2 null mice compared to the wild type counterparts. Increase in TGF-β signaling in response to angiotensin II was also lessened in cardiac fibroblasts isolated from the fibulin-2 null mice. The studies provide the first evidence that absence of fibulin-2 results in decreased up-regulation of TGF-β signaling after MI and protects against ventricular dysfunction, suggesting that fibulin-2 may be a potential therapeutic target for attenuating the progression of ventricular remodeling.     

Fibronectin splice variation in human knee cartilage,meniscus and synovial membrane: Observations in osteoarthritic knee

Fibronectin (FN) is a widely expressed molecule that can participate in development of osteoarthritis (OA) affecting cartilage, meniscus, and synovial membrane (SM). The alternatively spliced isoforms of FN in joint tissues other than cartilage have not been extensively studied previously. The present study compares FN splice variation in patients with varying degrees of osteoarthritic change. Joint tissues were collected from asymptomatic donors and patients undergoing arthroscopic procedures. Total RNA was amplified by PCR using primers flanking alternatively spliced Extra Domain A (EDA), Extra Domain B (EDB) and Variable (V) regions. EDB⁺, EDB^? and EDA^? and V⁺ variants were present in all joint tissues, while the EDA⁺ variant was rarely detected. Expression levels of EDB⁺ and EDV⁺ variants were similar in cartilage, synovium, and meniscal tissues. Synovial expression of V⁺ FN in arthroscopy patients varied with degree of cartilage degeneration. Two V^? isoforms, previously identified in cartilage, were also present in SM and meniscus. Fibronectin splicing in meniscus and SM bears striking resemblance to that of cartilage. Expression levels of synovial V⁺ FN varied with degree of cartilage degeneration. V⁺ FN should be investigated as a potential biomarker of disease stage or progression in larger populations. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:556–562, 2015.

     

Post-ischemic myocardial fibrosis occurs independent of hemodynamic changes

OBJECTIVES: Myocardial fibrosis is a major component of ventricular remodeling after large myocardial infarction (MI). The present study tests the hypothesis that post-ischemic myocardial fibrosis can occur independent of hemodynamic changes. METHODS: A mouse model of distal left coronary artery ligation was established to induce a small infarct (less than 15% of the left ventricle) in order to avoid significant mechanical overload after permanent myocardial ischemia. Left heart catheterization was performed to evaluate the post-infarct hemodynamics. Tissues from both ischemic and non-ischemic myocardium were examined for mRNA and protein expression at 24, 72 h and 7 days after ligation. RESULTS: Heart/body weight ratio after ligation was increased by approximately 10% over sham control although there is no statistically significant difference in hemodynamic parameters between the two groups. Non-ischemic myocardium distant from the infarct site showed molecular evidence of myocardial fibrosis 72 h and 7 days after ligation. There was marked up-regulation of mRNAs for extracellular matrix (ECM) proteins and their cross-linking enzyme, such as collagens type I, III and VI, and lysyl oxidase. Immunohistochemical study confirmed that the expression of these ECM proteins was significantly increased in the non-ischemic myocardium after 7 days. TGF-beta1 was up-regulated after 72 h in both ischemic and non-ischemic myocardium. CONCLUSIONS: Molecular and histopathological findings demonstrate that abnormal myocardial fibrosis can be induced by a small infarct independent of secondary hemodynamic changes.     

n‐Type Copolymers with Fluorene and 1,3,4‐Heterodiazole Moieties

Summary: The successful realization of n‐channel field‐effect transistors requires the application of semiconducting polymers with high electron mobility (n‐type). However, reports on n‐type polymers are rather scarce in the literature. Therefore, the development of polymers with suitable electron transport properties is particularly challenging for the synthetic chemistry. Main chain polymers with strong acceptor units, such as 1,3,4‐heterodiazoles, are potential candidates for electron transport materials in electronic devices. The fluorene unit is another ring system with interesting physical and chemical properties, which is often used in rigid‐rod, main chain polymers. The present work introduces the synthesis of organo‐soluble copolymers consisting of alternating fluorene‐, 1,3,4‐heterodiazole, and, in some cases, additional 2,5‐dialkoxyphenylene units in the main chain. The reported synthesis involves modified classical polycondensation as well as the tetrazole route. We demonstrate the possibility of exchanging oxygen in the heteroaromatic ring with sulfur using Lawesson's reagent during the ring closure reaction. An alternative structure of the heterocyclic ring with N‐phenyl in the oxygen position is feasible using the tetrazole synthetic route. The chemical and electrochemical properties of the copolyfluorenes are investigated in detail. Some of the synthesized copolyfluorenes have also been used for the preparation of “electron‐only” devices enabling the calculation of the electron mobilities. Further, an organic field‐effect transistor (OFET) characteristic was shown.

OFET characteristics of the polymer 12b .     

HLA-specific B cells: I. A method for their detection, quantification, and isolation using HLA tetramers

BACKGROUND: The development of highly sensitive and specific assays for detecting and characterizing HLA-specific antibodies has contributed to an appreciation of the extensive involvement of those antibodies in graft injury and dysfunction. However, understanding the regulatory processes of the humoral response to transplantation and the mechanisms underlying therapeutic agents and protocols for preventing and treating sensitization requires a way to study HLA-specific B cells. METHODS: Lymphocyte preparations enriched for B cells were stained with one or more of three different HLA tetramers. Tetramer-positive (tet+) B cells were enumerated and evaluated for an association of their frequencies with known sensitization. In some cases, tet+ B cells were isolated and placed in culture with supplements known to activate B cells in a nonspecific fashion. RESULTS: For all tetramers used, the frequencies of tet+ B cells were significantly higher (4.1%-5.5%) among sensitized patients than among nonsensitized patients (1.6%-3.2%, P<0.001). Binding of the tetramers occurred by the surface immunoglobulin antigen receptor with little or no binding to antibody captured in the Fc receptor. Cultured tet+ B cells produced antibodies specific for epitopes of the tetramer antigen. There appeared to be a certain amount of crossreactivity in the binding of tetramers. The frequency of CD27+ cells among tet+ B cells was higher, on average (34.4%-38.8%) than among all B cells (26.2%) whereas the frequencies of CD38 were comparable in the two groups. CONCLUSIONS: Staining with HLA tetramers provides a means for identifying, quantifying, and isolating HLA-specific B cells.     

Persistent Moderate-to-Weak Mediterranean Diet Adherence and Low Scoring for Plant-Based Foods across Several Southern European Countries: Are We Overlooking the Mediterranean Diet Recommendations?

The Mediterranean diet (MD) has been sponsored worldwide as a healthy and sustainable diet. Our aim was to update and compare MD adherence and food choices across several Southern European countries: Spain (SP), Portugal (PT), Italy (IT), Greece (GR), and Cyprus (CY) (MED, Mediterranean), and Bulgaria (BG) and the Republic of North Macedonia (NMK) (non-MED, non-Mediterranean). Participants (N = 3145, ≥18 y) completed a survey (MeDiWeB) with sociodemographic, anthropometric, and food questions (14-item Mediterranean Diet Adherence Screener, 14-MEDAS). The MED and non-MED populations showed moderate (7.08 ± 1.96) and weak (5.58 ± 1.82) MD adherence, respectively, with significant yet small differences across countries (SP > PT > GR > IT > CY > BG > NMK, p-value < 0.001). The MED participants scored higher than the non-MED ones for most of the Mediterranean-typical foods, with the greatest differences found for olive oil (OO) and white meat preference. In most countries, ≥70% of the participants reported quantities of red meat, butter, sweet drinks, and desserts below the recommended cutoff points, whereas <50% achieved the targets for plant-based foods, OO, fish, and wine. Being a woman and increasing age were associated with superior adherence (p-value < 0.001), but differences were rather small. Our results suggest that the campaigns carried out to support and reinforce the MD and to promote plant-based foods have limited success across Southern Europe, and that more hard-hitting strategies are needed.     

HLA-specific B cells: II. Application to transplantation

BACKGROUND: Differences in the antibody response to allogeneic transplantation exist between groups defined by race or gender. These differences may reflect differences in immune competency and/or exposure to alloantigens. We have investigated the frequencies and phenotypes of HLA-specific B cells to address those possibilities. METHODS: HLA-specific B cells were identified by staining with HLA tetramers (tet) as described previously and the distribution of CD27 and CD38 among those cells were measured in groups defined by various parameters. Possible correlation between frequencies of HLA-specific B cells and production of HLA-specific antibody after transplantation was also investigated. RESULTS: We found no correlation between the frequencies of CD27+tet+ (33%-44% vs. 34%-36%) or CD38+tet+ (57%-65% vs. 59%-66%) B cells and a previous mismatch for the HLA antigen of the tetramer. However, there was an increase in CD38+tet+ B cells among patients making antibody to the tetramer antigen (67%-72% vs. 53%-56%). Blacks had lower frequencies of CD27+ B cells than did whites (11.8% vs. 28.9%, P=0.003), but had greater increases of these cells among tet+ cells than did whites. There was a higher frequency of tet+ B cells among patients who developed "new" antibody to the HLA antigen (3.9%-8.6%) of the tetramer after transplantation than among those who did not (1.1%-3.7%). CONCLUSIONS: The phenotype of HLA-specific B cells reflects current or historic sensitization to HLA and may reflect inherent differences between groups defined by race and/or gender. The frequencies of HLA-specific B cells may predict patients at risk for production of donor-specific antibody after transplantation.     

Selective and nonselective benzodiazepine agonists have different effects on motor cortex excitability

Transcranial magnetic stimulation (TMS) is a useful method to study pharmacological effects on motor cortex excitability. Zolpidem is a selective agonist of the benzodiazepine receptor subtype BZ1 and has a distinct pharmacological profile compared to diazepam. To study the different effects of these two drugs on the cortical inhibitory system, TMS was performed before and after administration of a single oral dose of zolpidem (10 mg) and diazepam (5 mg) in six healthy volunteers. TMS tests included the determination of resting and active motor threshold (MT) and measurements of the amplitudes of motor evoked potentials, intracortical facilitation (ICF), short-latency intracortical inhibition (SICI), and long-latency intracortical inhibition (LICI), and determination of the cortical silent period (CSP). Both drugs were without effect on the active or resting MT and decreased the ICF. Prolongation of the CSP and enhancement of LICI only in the presence of zolpidem point to a specific BZ1-related mechanism underlying the long-lasting component of cortical inhibition. This selective modulation of the CSP and the LICI points to a specific role of BZ1 receptors in the control of inhibitory neuronal loops within the primary motor cortex.     

Inhibition of HIV type 1 replication in CD4+ and CD14+ cells purified from HIV type 1-infected individuals by the 2-5A agonist immunomodulator, 2-5A(N6B)

Two major interferon (IFN)-mediated antiviral defense enzymes are double-stranded (ds)RNA-dependent 2',5'-oligoadenylate (2-5A) synthetase (2-5OAS) and p68 kinase (PKR). When activated by dsRNA, 2-5OAS synthesizes 2-5A, which binds to and activates RNase L. Activated RNase L hydrolyzes single-stranded viral RNA, thereby inhibiting viral protein synthesis. HIV-1 inhibits the IFN-mediated intracellular antiviral pathways. We have reported the synthesis and characterization of a nuclease-resistant 2-5A agonist (2-5A(N6B)) that overcomes the HIV-1 induced blockades by restoring the 2-5OAS/RNase L antiviral pathway (Homan JW, et al., J Acquir Immune Defic Syndr 2002;30:9-20). The objective of this study was to test the effect of 2-5A(N6B) on chronically infected CD4(+) T lymphocytes and CD14(+) monocytes derived from HIV-1-seropositive individuals. Wild-type HIV-1 replication was effectively inhibited by 2-5A(N6B) in CD4(+) T lymphocytes and CD14(+) monocytes purified from HIV-1 seropositive individuals (n = 18) compared to untreated cells. We also assessed the cytotoxicity of 2-5A(N6B) and report that 2-5A(N6B) exerts its anti-HIV-1 activity with no evidence of cytotoxicity (IC(90) > 100,000 nM). Furthermore, 2-5A(N6B) did not alter the cellular RNA profile, affect CCR5 or CXCR4 coreceptor expression, or activate caspase-dependent apoptosis. Evidence is also provided to show that 2-5A(N6B), and naturally occurring 2-5A(4), act as ligands to activate human Toll-like receptor 4. These results indicate that the 2-5A agonist 2-5A(N6B) has the potential to enhance host cell innate and acquired immune defense mechanisms against HIV-1 infection.