. Wnt-induced secreted protein-1 is a prohypertrophic and profibrotic growth factor. Am J Physiol Heart Circ Physiol 293: H1839-H1846, 2007. First published July 6, 2007; doi:10.1152/ajpheart.00428.2007.-Wnt1-induced secreted protein-1 (WISP-1) is a member of the cysteine-rich 61, connective tissue growth factor, and nephroblastoma overexpressed (CCN) family of growth factors and is expressed in the heart at low basal levels. The purpose of this study was to investigate whether WISP-1 is upregulated in postinfarct myocardium and whether WISP-1 exerts prohypertrophic and mitogenic effects stimulating myocyte hypertrophy, cardiac fibroblast (CF) proliferation, and collagen expression. Male C57Bl/6 (25 g) mice underwent permanent occlusion of the left anterior descending coronary artery. mRNA and protein levels were analyzed by Northern and Western blot analyses. Cardiomyocyte hypertrophy was quantified by protein and DNA synthesis. CF proliferation was quantified by CyQuant assay, and soluble collagen release by Sircol assay. A time-dependent increase in WISP-1 expression was detected in vivo in the noninfarct zone of the left ventricle, which peaked at 24 h (3.1-fold, P Ͻ 0.01). Similarly, biglycan expression was increased by 3.71-fold (P Ͻ 0.01). IL-1␤ and TNF-␣ expression preceded WISP-1 expression in vivo and stimulated WISP-1 expression in neonatal rat ventricular myocytes in vitro. WISP-1-induced cardiomyocyte hypertrophy was evidenced by increased protein (2.78-fold), but not DNA synthesis, and enhanced Akt phosphorylation and activity. Treatment of primary CF with WISP-1 significantly stimulated proliferation at 48 h (6,966 Ϯ 264 vs. 5,476 Ϯ 307 cells/well, P Ͻ 0.01) and enhanced collagen release by 72 h (18.4 Ϯ 3.1 vs. 8.4 Ϯ 1.0 ng/cell, P Ͻ 0.01). Our results demonstrate for the first time that WISP-1 and biglycan are upregulated in the noninfarcted myocardium in vivo, suggesting a positive amplification of WISP-1 signaling. WISP-1 stimulates cardiomyocyte hypertrophy, fibroblast proliferation, and ECM expression in vitro. These results suggest that WISP-1 may play a critical role in post-myocardial infarction remodeling.cysteine-rich 61, connective tissue growth factor, and nephroblastoma overexpressed family; myocardial infarction; myocardial remodeling; Akt; cardiomyocyte hypertrophy WNT1-INDUCED secreted protein-1 (WISP-1) is a member of the cysteine-rich 61, connective tissue growth factor (CTGF), and nephroblastoma overexpressed (CCN) family of growth factors shown to play a role in cellular growth, transformation, and survival (24,26,52,57). Because of the limited regenerative capacity of the heart, any structural adaptations of the myocardium occurring in response to chronic changes in hemodynamic loading conditions typically require alterations in the size of myocytes and composition of the interstitial components (46). When the stimulus is chronic pressure overload, as in hypertension or aortic stenosis, cardiac myocytes increase in diameter and there is increased deposition of interstitial col...

Reperfusion after a brief period of ischemia caused induction of myocardial C/EBP (beta-subunit). The rapid and sustained production of IL-6 with concomitant expression of IL-6 receptor and gp130 suggest that these factors may participate in a local inflammatory cascade after myocardial ischemia and reperfusion.

The life-prolonging effects of calorie restriction (CR) may be due to reduced damage from cumulative oxidative stress. Our goal was to determine the long-term effects of moderate dietary CR on the myocardial response to reperfusion after a single episode of sublethal ischemia. Male Fisher 344 rats were fed either an ad libitum (AL) or CR (40% less calories) diet. At age 12 mo the animals were anaesthetized and subjected to thoracotomy and a 15-min left-anterior descending coronary artery occlusion. The hearts were reperfused for various periods. GSH and GSSG levels, nuclear factor-kappaB (NF-kappaB) DNA binding activity, cytokine, and antioxidant enzyme expression were assessed in the ischemic zones. Sham-operated animals served as controls. Compared with the AL diet, chronic CR limited oxidative stress as seen by rapid recovery in GSH levels in previously ischemic myocardium. CR reduced DNA binding activity of NF-kappaB. The kappaB-responsive cytokines interleukin-1beta and tumor necrosis factor-alpha were transiently expressed in the CR group but persisted longer in the AL group. Furthermore, expression of manganese superoxide dismutase, a key antioxidant enzyme, was significantly delayed in the AL group. Collectively these data indicate that CR significantly attenuates myocardial oxidative stress and the postischemic inflammatory response.

We have previously reported that induction of nuclear factor-kappa B (NF-kappa B) occurs in a biphasic manner in postischemic myocardium. Because interleukin-1 (IL-1), IL-6, tumor necrosis factor-alpha (TNF-alpha), and inducible nitric-oxide synthase (iNOS) contain kappa B-response elements, and since transforming growth factor-beta 1 (TGF-beta 1) down-modulates both cytokine and iNOS expression, we studied their temporal expression during myocardial ischemia/reperfusion (I/R). Northern and Western analyses showed low levels of IL-6 and no signal for IL-1 beta, TNF-alpha and iNOS under basal conditions. Their expression rose significantly over sham-operated controls by 1 h reperfusion, and persisted high for various periods. Under basal conditions, low levels of TGF-beta 1 were detected, which rose significantly at 3 h reperfusion, and remained high until 24 h reperfusion. Administration of diethyldithiocarbamate (DDC) inhibited induction of NF-kappa B and concomitantly the expression of IL-1 beta, IL-6, TNF-alpha as well as iNOS. However, expression of TGF-beta was not altered. Our results indicate that ischemia/reperfusion induces NF-kappa B, and upregulates kappa B-response genes. Administration of DDC inhibits NF-kappa B levels, and attenuates expression of inflammatory cytokines and iNOS.

Stimulated production of reactive oxygen species (ROS) by plasma membrane-associated nicotinamide adenine dinucleotide phosphate oxidases (Nox) in non-phagocytic cells regulates a number of biological processes including growth, vessel tone, and oxygen sensing. The purpose of this study was to investigate H 2 O 2 -stimulated ROS production in primary adult cardiac fibroblasts (CF). Results demonstrate that CF express an H 2 O 2 -inducible oxidant generating system that is inhibitable by diphenylene iodonium (DPI) and sensitive to antioxidants. In addition to H 2 O 2 , generation of ROS was stimulated potently by 1-oleoyl-2-acetyl-sn-glycerol (OAG) and arachidonic acid (AA) in a protein kinase C-independent manner. Pretreatment with arachidonyl trifluoromethyl ketone was nearly as effective as DPI at reducing H 2 O 2 -and OAG-stimulated oxidant generation indicating a central role for phospholipase A 2 (PLA 2 ) in this signaling pathway. Co-stimulation with H 2 O 2 and OAG did not increase ROS generation as compared to OAG alone suggesting both agonists signal through a shared, rate-limited enzymatic pathway involving PLA 2 . Co-stimulation with H 2 O 2 and AA had additive effects indicating these two agonists stimulate oxidant production through a parallel activation pathway. Reverse transcriptase-coupled polymerase chain reaction and Western blotting demonstrate primary cardiac fibroblasts express transcripts and protein for Nox4, p22, p47, and p67 phox. Transfections with Nox4 small inhibitory ribonucleic acid oligonucleotides or p22 phox antisense oligonucleotides significantly downregulated stimulated Nox activity. Inhibitors of nitric oxide synthases were without effect. We conclude adult CF express Nox4/p22 phox-containing oxidant generating complex activated by H 2 O 2 , OAG, and AA through a pathway that requires activation of PLA 2 .

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Interleukin (IL)-18 is a cardiotropic proinflammatory cytokine chronically elevated in the serum of patients with cardiac hypertrophy (LVH). The purpose of this study was to examine the role of IL-18 in pressure-overload hypertrophy using wild type (WT) and IL-18 −/− (null) mice. Adult male C57Bl/ 6 mice underwent transaortic constriction (TAC) for 7 days or sham surgery. Heart weight/body weight ratios showed blunted hypertrophy in IL-18 null TAC mice compared to WT TAC animals. Microarray analyses indicated differential expression of hypertrophy-related genes in WT versus IL-18 nulls. Northern, Western, and EMSA analyses showed Akt and GATA4 were increased in WT but unchanged in IL-18 null mice. Our results demonstrate blunted hypertrophy with reduced expression of contractile-, hypertrophy-, and remodeling-associated genes following pressure overload in IL-18 null mice, and suggest that IL-18 plays a critical role in the hypertrophic response.

The objective of this study was to determine whether heme oxygenase-1 (HO-1) or heme metabolites exert cytoprotective effects on interleukin-18-mediated endothelial cell (EC) death. Treatment with IL-18 increased NF-κB activation, PTEN induction, suppressed Akt activation, and stimulated EC death. While ectopic expression of p65 enhanced PTEN transcription, adenoviral transduction of dnIκB-α, dnp65, or dnIKKβ was inhibitory. Furthermore, IL-18 suppressed HO-1 mRNA expression via enhanced mRNA degradation. Overexpression of HO-1, treatment with HO-1 inducer hemin or the CO donor Cobalt (III) protoporphyrin IX all reversed IL-18-mediated NF-κB activation, PTEN induction, Akt suppression, and EC death. Furthermore, hemin induced HO-1 expression, and HO-1 knockdown, HO-1 inhibition, or CO scavengers all reversed the pro-survival effects of hemin. In addition, the CO donors CORM-1 and CORM-3 and the heme metabolites biliverdin and bilirubin attenuated IL-18-induced EC death via a similar signaling pathway. IL-18 induced p38α MAPK activation, and suppressed p38β isoform expression. While p38α knockdown attenuated, p38β knockdown potentiated IL-18-mediated EC death. Hemin and HO-1 reversed IL-18-mediated p38α induction, and restored p38β levels. These results demonstrate that IL-18 suppresses HO-1 expression and induces EC death. HO-1 overexpression, HO-1 induction, or treatment with heme metabolites all reverse IL-18-mediated p38α MAPK and NF-κB activation, PTEN induction, Akt suppression, and EC death. Thus, HO-1 inducers and CO donors may have the therapeutic potential to effectively block IL-18 signaling and reduce IL-18-dependent vascular injury and inflammation.