Differential Regulation of Matrix Metalloproteinase-2 and -9 Expression and Activity in Adult Rat Cardiac Fibroblasts in Response to Interleukin-1β

Matrix metalloproteinases (MMPs), a family of endoproteinases, are implicated in cardiac remodeling. Interleukin-1β (IL-1β), which is increased in the heart following myocardial infarction, increases expression and activity of MMP-2 (gelatinase A) and -9 (gelatinase B) in cardiac fibroblasts. Previously, we have shown that IL-1β activates ERK1/2, JNKs, and protein kinase C (PKC). However, signaling pathways involved in the regulation of MMP-2 and -9 expression and activity are not yet well understood. Using adult rat cardiac fibroblasts, we show that inhibition of ERK1/2 and JNKs inhibits IL-1β-stimulated increases in MMP-9, not MMP-2, expression and activity. Chelerythrine, an inhibitor of PKC, inhibited activation of ERK1/2 and JNKs and expression and activity of both MMPs. Selective inhibition of PKC-α/β1 using Gö6976 inhibited JNKs activation and the expression and activity of MMP-9, not MMP-2. Inhibition of PKC-θ and PKC-ζ using pseudosubstrates inhibited IL-1β-stimulated activation of ERK1/2 and JNKs and the expression and activity of MMP-2 and -9. Inhibition of PKC-ε had no effect. IL-1β activated NF-κB pathway as measured by increased phosphorylation of IKKα/β and Inhibition of ERK1/2, JNKs, and PKC-α/β1 had no effect on NF-κB activation, whereas inhibition of PKC-θ and PKC-ζ inhibited IL-1β-stimulated activation of NF-κB. SN50, NF-κB inhibitor peptide, inhibited IL-1β-stimulated increases in MMP-2 and -9 expression and activity. These observations suggest that 1) activation of ERK1/2 and JNKs plays a critical role in the regulation of MMP-9, not MMP-2, expression and activity; 2) PKC-α/β1 act upstream of JNKs, not ERK1/2; 3) PKC-ζ and -θ, not PKC-ε, act upstream of JNKs, ERK1/2, and NF-κB; and 4) activation of NF-κB stimulates expression and activity of MMP-2 and -9

Study of penetration depth as a function of temperature, in-plane hopping and single particle tunneling in cuprate superconductors

The present study deals with the study of penetration depth as a function of in-plane hopping matrix element, single particle tunneling between the layers and temperature in bilayer high temperature cuprate superconducting materials. For this purpose, a tight binding bilayer Hubbard Hamiltonian has been considered that includes the in-plane (within CuO2 plane) and out-of-plane interactions. Employing Green’s function technique, the expressions for superconducting order parameters, carrier density and penetration depth are obtained. The numerical analysis shows that in bilayer cuprates the penetration depth depends on in-plane hopping matrix element, single particle tunneling as well as on temperature in an essential way. Finally, we have compared our theoretical results on penetration depth with that of recent experimental results and found to be in qualitative agreement

β-Adrenergic Receptor-Stimulated Cardiac Myocyte Apoptosis: Role of β1 Integrins

Increased sympathetic nerve activity to the myocardium is a central feature in patients with heart failure. Accumulation of catecholamines plays an important role in the pathogenesis of heart disease. Acting via β-adrenergic receptors (β-AR), catecholamines (norepinephrine and isoproterenol) increase cardiac myocyte apoptosis in vitro and in vivo. Specifically, β1-AR and β2-AR coupled to Gαs exert a proapoptotic action, while β2-AR coupled to Gi exerts an antiapoptotic action. β1 integrin signaling protects cardiac myocytes against β-AR-stimulated apoptosis in vitro and in vivo. Interaction of matrix metalloproteinase-2 (MMP-2) with β1 integrins interferes with the survival signals initiated by β1 integrins. This paper will discuss background information on β-AR and integrin signaling and summarize the role of β1 integrins in β-AR-stimulated cardiac myocyte apoptosis

NF2 Signaling Pathway Plays a Pro-Apoptotic Role in β-Adrenergic Receptor Stimulated Cardiac Myocyte Apoptosis

This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication. β-adrenergic receptor (β-AR) stimulation induces cardiac myocyte apoptosis in vitro and in vivo. Neurofibromin 2 (NF2) is a member of the ezrin/radixin/moesin (ERM) family of proteins. Post-translational modifications such as phosphorylation and sumoylation affect NF2 activity, subcellular localization and function. Here, we tested the hypothesis that β-AR stimulation induces post-translational modifications of NF2, and NF2 plays a pro-apoptotic role in β-AR-stimulated myocyte apoptosis. Methods and results Treatment of adult rat ventricular myocytes (ARVMs) with β-AR agonist (isoproterenol) for 15 min increased phosphorylation (serine-518) and sumoylation of NF2. Co-immunoprecipi-tation assay confirmed β-AR-stimulated sumoylation of NF2. β-AR stimulation enhanced nuclear translocation of phosphorylated and sumoylated NF2. Specific inhibition of β1-AR and protein kinase A (PKA) decreased β-AR-stimulated increase in NF2 post-translational modifications, while inhibition of β2-AR had no effect. Activation of adenylyl cyclase using forskolin (FSK) mimicked the effects of β-AR stimulation. β-AR stimulation and expression of wild-type (WT)-NF2 using adenoviruses increased phosphorylation of mammalian sterile like kinase-1/2 (MST1/2) and yes activated protein (YAP), downstream targets of NF2. Knockdown of NF2 using siRNA in H9C2 cardiomyocytes decreased β-AR-stimulated increase in NF2 and YAP phosphorylation. siRNA-mediated knockdown of NF2 decreased β-AR-stimulated increase in apoptosis, while expression of WT-NF2 induced apoptosis in ARVMs. Expression of WT-NF2 stimulated the mitochondrial death pathway as evidenced by activation of c-Jun N-terminal Kinases (JNKs), and increase in cytosolic cytochrome c levels and Bax expression. Conclusion β-AR stimulation affects post-translational modifications of NF2 via the involvement β1-AR/PKA/cAMP pathway, and NF2 plays a pro-apoptotic role in β-AR-stimulated myocyte apoptosis via the phosphorylation (inactivation) of YAP and involvement of mitochondrial death pathway

Combined free flap and ilizarov bone reconstruction in complex lower limb trauma: our experience

Background: Reconstruction of complex lower limb trauma is a major concern for both plastic and Orthopedic surgeons. The use of free flap with Ilizarov method for soft tissue coverage and bone reconstruction not only gives the patient near normal shape and function but also allows early mobilization of the patient, even during the process of distraction with Ilizarov method.Methods: In this study patients with bone and soft tissue defects of the lower leg were included in the study. Our protocol was immediate wound debridement along with application of external fixator and early free flap coverage within 48-72 hours. After 3-4 weeks of the free flap transfer definitive bone reconstruction is done with Ilizarov method.Results: 122 flaps survived fully and distal flap necrosis occurred in 4 patients. Necrosis of flap occurred before the start of bone reconstruction with Ilizarov and was managed conservatively or with skin graft. Pin tract infection occurred in 45 (35.71%) patients and was treated by pin care and antibiotics. Other complications in treated patients included pain due to distraction (33.33%). delayed union at docking site (11.90%), discrepancy of limb size (9.52%) and union with deformity (6.35%). The functional outcome was satisfactory in majority of the cases.Conclusions: Combined use of free flap and Ilizarov provides a more reliable soft tissue coverage and bone reconstruction with almost near normal shape and function. It has advantages like regenerating same quality bone and allowing the early mobilization of the patient with acceptable rate of complications

Osteopontin: Role in Extracellular Matrix Deposition and Myocardial Remodeling Post-MI

Remodeling after myocardial infarction (MI) associates with left ventricular (LV) dilation, decreased cardiac function and increased mortality. The dynamic synthesis and breakdown of extracellular matrix (ECM) proteins play a significant role in myocardial remodeling post-MI. Expression of osteopontin (OPN) increases in the heart post-MI. Evidence has been provided that lack of OPN induces LV dilation which associates with decreased collagen synthesis and deposition. Inhibition of matrix metalloproteinases, key players in ECM remodeling process post-MI, increased ECM deposition (fibrosis) and improved LV function in mice lacking OPN after MI. This review summarizes — 1) signaling pathways leading to increased expression of OPN in the heart; 2) the alterations in the structure and function of the heart post-MI in mice lacking OPN; and 3) mechanisms involved in OPN-mediated ECM remodeling post-MI

Ataxia Telangiectasia Mutated Kinase Plays a Protective Role in β-Adrenergic Receptor-Stimulated Cardiac Myocyte Apoptosis and Myocardial Remodeling

β-Adrenergic receptor (β-AR) stimulation induces cardiac myocyte apoptosis and plays an important role in myocardial remodeling. Here we investigated expression of various apoptosis-related genes affected by β-AR stimulation, and examined first time the role of ataxia telangiectasia mutated kinase (ATM) in cardiac myocyte apoptosis and myocardial remodeling following β-AR stimulation. cDNA array analysis of 96 apoptosis-related genes indicated that β-AR stimulation increases expression of ATM in the heart. In vitro, RT-PCR confirmed increased ATM expression in adult cardiac myocytes in response to β-AR stimulation. Analysis of left ventricular structural and functional remodeling of the heart in wild-type (WT) and ATM heterozygous knockout mice (hKO) 28 days after ISO-infusion showed increased heart weight to body weight ratio in both groups. M-mode echocardiography showed increased percent fractional shortening (%FS) and ejection fraction (EF%) in both groups 28 days post ISO-infusion. Interestingly, the increase in %FS and EF% was significantly lower in the hKO-ISO group. Cardiac fibrosis and myocyte apoptosis were higher in hKO mice at baseline and ISO-infusion increased fibrosis and apoptosis to a greater extent in hKO-ISO hearts. ISO-infusion increased phosphorylation of p53 (Serine-15) and expression of p53 and Bax to a similar extent in both groups. hKO-Sham and hKO-ISO hearts exhibited reduced intact β1 integrin levels. MMP-2 protein levels were significantly higher, while TIMP-2 protein levels were lower in hKO-ISO hearts. MMP-9 protein levels were increased in WT-ISO, not in hKO hearts. In conclusion, ATM plays a protective role in cardiac remodeling in response to β-AR stimulation

Osteopontin Inhibits Interleukin-1β-Stimulated Increases in Matrix Metalloproteinase Activity in Adult Rat Cardiac Fibroblasts: Role of Protein Kinase C-ζ

We have shown that osteopontin (OPN), an extracellular matrix protein, plays an important role in post myocardial infarction (MI) remodeling by promoting collagen synthesis and accumulation. Interleukin-1β (IL-1β), increased in the heart following MI, increases matrix metalloproteinase (MMP) activity in cardiac fibroblasts in vitro. Here, we show that OPN alone has no effect on MMP activity or expression. However, it reduces IL-1β-stimulated increases in MMP activity and expression in adult rat cardiac fibroblasts. Pretreatment with bovine serum albumin had no effect on MMP activity or protein content, whereas GRGDS (glycine-arginine-glycine-aspartic acid-serine)- pentapeptide (which interrupts binding of RGD-containing proteins to cell surface integrins) and monoclonal antibody m7E3 (a rat β3 integrins antagonist) inhibited the effects of OPN. Inhibition of PKC using chelerythrine inhibited the activities of both MMP-2 and MMP-9. Stimulation of cells using IL-1β increased phosphorylation and translocation of PKC to membrane fractions, which was inhibited by OPN. OPN inhibited IL-1β-stimulated increases in translocation of PKC-ζ from cytosolic to membrane fractions. Furthermore, the levels of phospho-PKC-ζ were lower in the cytosolic fractions of OPN knock-out mice hearts as compared with wild type 6 days post-MI. Inhibition of PKC-ζ using PKC-ζ pseudosubstrate inhibited IL-1β-stimulated increases in MMP-2 and MMP-9 activities. These observations suggest that OPN, acting via 3 integrins, inhibits IL-1β-stimulated increases in MMP-2 and MMP-9 activity, at least in part, via the involvement of PKC-ζ. Thus, OPN may play a key role in collagen deposition during myocardial remodeling following MI by modulating cytokine-stimulated MMP activity

β-Adrenergic Receptor Stimulation Induces Endoplasmic Reticulum Stress in Adult Cardiac Myocytes: Role in Apoptosis

Accumulation of misfolded proteins and alterations in calcium homeostasis induces endoplasmic reticulum (ER) stress, leading to apoptosis. In this study, we tested the hypothesis that β-AR stimulation induces ER stress, and induction of ER stress plays a pro-apoptotic role in cardiac myocytes. Using thapsigargin and brefeldin A, we demonstrate that ER stress induces apoptosis in adult rat ventricular myocytes (ARVMs). β-AR-stimulation (isoproterenol; 3h) significantly increased expression of ER stress proteins, such as GRP-78, Gadd-153, and Gadd-34, while activating caspase-12 in ARVMs. In most parts, these effects were mimicked by thapsigargin. β-AR stimulation for 15 min increased PERK and eIF-2α phosphorylation. PERK phosphorylation remained higher, while eIF-2α phosphorylation declined thereafter, reaching to ∼50% below basal levels at 3 h after β-AR stimulation. This decline in eIF-2a phosphorylation was prevented by β1-AR, not by β2-AR antagonist. Forskolin, adenylyl cyclase activator, simulated the effects of ISO on eIF-2α phosphorylation. Salubrinal (SAL), an ER stress inhibitor, maintained eIF-2α phosphorylation and inhibited β-ARstimulated apoptosis. Furthermore, inhibition of caspase-12 using z-ATAD inhibited β-AR-stimulated and thapsigargininduced apoptosis. In vivo, β-AR stimulation induced ER stress in the mouse heart as evidenced by increased expression of GRP-78 and Gadd-153, activation of caspase-12, and dephosphorylation of eIF-2α. SAL maintained phosphorylation of eIF-2α, inhibited activation of caspase-12, and decreased β-AR-stimulated apoptosis in the heart. Thus, β-AR stimulation induces ER stress in cardiac myocytes and in the heart, and induction of ER stress plays a pro-apoptotic role

Research Output and Citation Analysis of Leading Global Engineering Research Countries during 2002-16

In the present study, output and citation analysis of research activities in engineering in the world are mapped during 2002-2016.The study aims to promote the awareness of the global research output in engineering. With this aim, Scimago Journal & Country Rank data (Scopus® database of Elsevier) has been accessed for obtaining the required scholarly publication data. An attempt for evaluation on different qualitative and quantitative parameters like number of publications, citation analysis, research output, and h-index has been done. With these indicators in the research, analysis and assessment of total 7252275 publications from engineering field were done. The results show that out of the total research output, China stands first with 22.22% share of the research and is followed by United States (17.78%) and Japan (6.04%). Outstanding countries in engineering research have significant impact and 68.93% of the total global engineering research has been done in 10 leading countries. During the period of study, the research output of engineering has improved considerably with an average annual growth of 6.88