Fibroblast Growth Factor-9 Enhances M2 Macrophage Differentiation and Attenuates Adverse Cardiac Remodeling in the Infarcted Diabetic Heart

Inflammation has been implicated as a perpetrator of diabetes and its associated complications. Monocytes, key mediators of inflammation, differentiate into pro-inflammatory M1 macrophages and anti-inflammatory M2 macrophages upon infiltration of damaged tissue. However, the inflammatory cell types, which propagate diabetes progression and consequential adverse disorders, remain unclear. The current study was undertaken to assess monocyte infiltration and the role of fibroblast growth factor-9 (FGF-9) on monocyte to macrophage differentiation and cardioprotection in the diabetic infarcted heart. Db/db diabetic mice were assigned to sham, myocardial infarction (MI), and MI+FGF-9 groups. MI was induced by permanent coronary artery ligation and animals were subjected to 2D transthoracic echocardiography two weeks post-surgery. Immunohistochemical and immunoassay results from heart samples collected suggest significantly increased infiltration of monocytes (Mean +/- SEM; MI: 2.02% +/- 0.23% vs. Sham 0.75% +/- 0.07%; p \u3c 0.05) and associated pro-inflammatory cytokines (TNF-alpha, MCP-1, and IL-6), adverse cardiac remodeling (Mean +/- SEM; MI: 33% +/- 3.04% vs. Sham 2.2% +/- 0.33%; p \u3c 0.05), and left ventricular dysfunction (Mean +/- SEM; MI: 35.4% +/- 1.25% vs. Sham 49.19% +/- 1.07%; p \u3c 0.05) in the MI group. Importantly, treatment of diabetic infarcted myocardium with FGF-9 resulted in significantly decreased monocyte infiltration (Mean +/- SEM; MI+FGF-9: 1.39% +/- 0.1% vs. MI: 2.02% +/- 0.23%; p \u3c 0.05), increased M2 macrophage differentiation (Mean +/- SEM; MI+FGF-9: 4.82% +/- 0.86% vs. MI: 0.85% +/- 0.3%; p \u3c 0.05) and associated anti-inflammatory cytokines (IL-10 and IL-1RA), reduced adverse remodeling (Mean +/- SEM; MI+FGF-9: 11.59% +/- 1.2% vs. MI: 33% +/- 3.04%; p \u3c 0.05), and improved cardiac function (Fractional shortening, Mean +/- SEM; MI+FGF-9: 41.51% +/- 1.68% vs. MI: 35.4% +/- 1.25%; p \u3c 0.05). In conclusion, our data suggest FGF-9 possesses novel therapeutic potential in its ability to mediate monocyte to M2 differentiation and confer cardiac protection in the post-MI diabetic heart

Regulation of PTEN/Akt Pathway Enhances Cardiomyogenesis and Attenuates Adverse Left Ventricular Remodeling following Thymosin beta 4 Overexpressing Embryonic Stem Cell Transplantation in the Infarcted Heart

Thymosin beta 4 (T beta 4), a small G-actin sequestering peptide, mediates cell proliferation, migration, and angiogenesis. Whether embryonic stem (ES) cells, overexpressing T beta 4, readily differentiate into cardiac myocytes in vitro and in vivo and enhance cardioprotection following transplantation post myocardial infarction (MI) remains unknown. Accordingly, we established stable mouse ES cell lines, RFP-ESCs and T beta 4-ESCs, expressing RFP and an RFP-T beta 4 fusion protein, respectively. In vitro, the number of spontaneously beating embryoid bodies (EBs) was significantly increased in T beta 4-ESCs at day 9, 12 and 15, compared with RFP-ESCs. Enhanced expression of cardiac transcriptional factors GATA-4, Mef2c and Txb6 in T beta 4-EBs, as confirmed with real time-PCR analysis, was accompanied by the increased number of EB areas stained positive for sarcomeric alpha-actin in T beta 4-EBs, compared with the RFP control, suggesting a significant increase in functional cardiac myocytes. Furthermore, we transplanted T beta 4-ESCs into the infarcted mouse heart and performed morphological and functional analysis 2 weeks after MI. There was a significant increase in newly formed cardiac myocytes associated with the Notch pathway, a decrease in apoptotic nuclei mediated by an increase in Akt and a decrease in levels of PTEN. Cardiac fibrosis was significantly reduced, and left ventricular function was significantly augmented in the T beta 4-ESC transplanted group, compared with controls. It is concluded that genetically modified T beta 4-ESCs, potentiates their ability to turn into cardiac myocytes in vitro as well as in vivo. Moreover, we also demonstrate that there was a significant decrease in both cardiac apoptosis and fibrosis, thus improving cardiac function in the infarcted heart

Regulation Of Notch 1 Signaling In Thp-1 Cells Enhances M2 Macrophage Differentiation

Macrophage polarization is emerging as an important area of research for the development of novel therapeutics to treat inflammatory diseases. Within the current study, the role of Notch1R in macrophage differentiation was investigated as well as downstream effects in THP-1 monocytes cultured in “inflammation mimicry” media. Interference of Notch signaling was achieved using either the pharmaceutical inhibitor DAPT or Notch1R small interfering RNA (siRNA), and Notch1R expression, macrophage phenotypes, and anti- and proinflammatory cytokine expression were evaluated. Data presented show that Notch1R expression on M1 macrophages as well as M1 macrophage differentiation is significantly elevated during cellular stress (P \u3c 0.05). However, under identical culture conditions, interference to Notch signaling via Notch1R inhibition mitigated these results as well as promoted M2 macrophage differentiation. Moreover, when subjected to cellular stress, macrophage secretion of proinflammatory cytokines was significantly heightened (P \u3c 0.05). Importantly, Notch1R inhibition not only diminished proinflammatory cytokine secretion but also enhanced anti-inflammatory protein release (P \u3c 0.05). Our data suggest that Notch1R plays a pivotal role in M1 macrophage differentiation and heightened inflammatory responses. Therefore, we conclude that inhibition of Notch1R and subsequent downstream signaling enhances monocyte to M2 polarized macrophage outcomes and promotes anti-inflammatory mediation during cellular stress

Fibroblast Growth Factor-8 Inhibits Oxidative Stress-Induced Apoptosis In H9C2 Cells

Fibroblast growth factors (FGFs) comprise a large family of signaling molecules that involve cell patterning, mobilization, differentiation, and proliferation. Various FGFs, including FGF-1, FGF-2, and FGF-5, have been shown to play a role in cytoprotection during adverse cardiac events; however, whether FGF-8 is a cytoprotective remains unclear. The current study was designed to evaluate the effect of FGF-8 treatment on oxidative stress-induced apoptosis in H9c2 cells. Cells were divided into three groups: control, H2O2 (400 µm H2O2), and H2O2 + FGF-8 (4 ng/ml FGF-8). Our results suggest apoptosis was significantly (p \u3c 0.05) enhanced in the H2O2 group relative to control. Moreover, a significant (p \u3c 0.05) decline in apoptosis was observed in the H2O2 + FGF-8 group compared to H2O2-treated cells as evidenced by TUNEL staining, a cell death detection ELISA, and cell viability. Levels of downstream apoptotic mediators, caspase-3 and caspase-9, were significantly (p \u3c 0.05) upregulated following H2O2 treatment but were abrogated following FGF-8 application. Expression levels of Forkhead box protein O1 (FoxO-1), MnSOD, catalase, pAKT, and p-mTOR were significantly (p \u3c 0.05) reduced in the H2O2 group (p \u3c 0.05). Notably, these levels were significantly (p \u3c 0.05) reversed following FGF-8 treatment. Our data, for the first time, suggest FGF-8 is an anti-apoptotic mediator in oxidative-stressed H9c2 cells. Furthermore, our data demonstrate that apoptotic inhibition by FGF-8 is consequent to FoxO-1 oxidative detoxification as well as augmentation to the PI3K/AKT cell survival pathway

Factors Released From Embryonic Stem Cells Inhibit Apoptosis In H9C2 Cells Through Pi3K/Akt But Not Erk Pathway

We recently reported that embryonic stem cells-conditioned medium (ES-CM) contains antiapoptotic factors that inhibit apoptosis in the cardiac myoblast H9c2 cells. However, the mechanisms of inhibited apoptosis remain elusive. In this report, we provide evidence for the novel mechanisms involved in the inhibition of apoptosis provided by ES-CM. ES-CM from mouse ES cells was generated. Apoptosis was induced after exposure with H2O2 (400 μm) in H9c2 cells followed by the replacement with ES-CM or culture medium. H9c2 cells treated with H2O2 were exposed to ES-CM, and ES-CM plus cell survival protein phosphatidylinositol 3-kinase/Akt inhibitor, LY-294002, or extracellular signal-regulated kinase (ERK1/2) inhibitor, PD-98050. After 24 h, H9c2 cells treated with ES-CM demonstrated a significant increase in cell survival. ES-CM significantly inhibited (P \u3c 0.05) apoptosis determined by terminal deoxynucleotidyl transferase dUTP-mediated nickend labeling staining, apoptotic ELISA, and caspase-3 activity. Importantly, enhanced cell survival and inhibited apoptosis with ES-CM was abolished with LY-294002. In contrast, PD-98050 shows no effect on ES-CM-increased cell survival. Furthermore, H2O2-induced apoptosis is associated with decreased levels of phosphorylated (p)Akt activity. Following treatment with ES-CM, we observed a decrease in apoptosis with an increase in pAkt, and the increased activity was attenuated with the Akt inhibitor, suggesting that the Akt pathway is involved in the decreased apoptosis and cell survival provided by ES-CM. In contrast, we observed no change in ES-CM-decreased apoptosis or pERK with PD-98050. In conclusion, we suggest that ES-CM inhibited apoptosis and is mediated by Akt but not the ERK pathway. Copyright © 2008 the American Physiological Society

Factors released from embryonic stem cells inhibit apoptosis in H9c2 cells through PI3K/Akt but not ERK pathway

We recently reported that embryonic stem cells-conditioned medium (ES-CM) contains antiapoptotic factors that inhibit apoptosis in the cardiac myoblast H9c2 cells. However, the mechanisms of inhibited apoptosis remain elusive. In this report, we provide evidence for the novel mechanisms involved in the inhibition of apoptosis provided by ES-CM. ES-CM from mouse ES cells was generated. Apoptosis was induced after exposure with H2O2 (400 μm) in H9c2 cells followed by the replacement with ES-CM or culture medium. H9c2 cells treated with H2O2 were exposed to ES-CM, and ES-CM plus cell survival protein phosphatidylinositol 3-kinase/Akt inhibitor, LY-294002, or extracellular signal-regulated kinase (ERK1/2) inhibitor, PD-98050. After 24 h, H9c2 cells treated with ES-CM demonstrated a significant increase in cell survival. ES-CM significantly inhibited (P < 0.05) apoptosis determined by terminal deoxynucleotidyl transferase dUTP-mediated nick-end labeling staining, apoptotic ELISA, and caspase-3 activity. Importantly, enhanced cell survival and inhibited apoptosis with ES-CM was abolished with LY-294002. In contrast, PD-98050 shows no effect on ES-CM-increased cell survival. Furthermore, H2O2-induced apoptosis is associated with decreased levels of phosphorylated (p)Akt activity. Following treatment with ES-CM, we observed a decrease in apoptosis with an increase in pAkt, and the increased activity was attenuated with the Akt inhibitor, suggesting that the Akt pathway is involved in the decreased apoptosis and cell survival provided by ES-CM. In contrast, we observed no change in ES-CM-decreased apoptosis or pERK with PD-98050. In conclusion, we suggest that ES-CM inhibited apoptosis and is mediated by Akt but not the ERK pathway

Regulation of Notch 1 signaling in THP-1 cells enhances M 2

Macrophage polarization is emerging as an important area of research for the development of novel therapeutics to treat inflammatory diseases. Within the current study, the role of Notch1R in macrophage differentiation was investigated as well as downstream effects in THP-1 monocytes cultured in “inflammation mimicry” media. Interference of Notch signaling was achieved using either the pharmaceutical inhibitor DAPT or Notch1R small interfering RNA (siRNA), and Notch1R expression, macrophage phenotypes, and anti- and proinflammatory cytokine expression were evaluated. Data presented show that Notch1R expression on M(1) macrophages as well as M(1) macrophage differentiation is significantly elevated during cellular stress (P < 0.05). However, under identical culture conditions, interference to Notch signaling via Notch1R inhibition mitigated these results as well as promoted M(2) macrophage differentiation. Moreover, when subjected to cellular stress, macrophage secretion of proinflammatory cytokines was significantly heightened (P < 0.05). Importantly, Notch1R inhibition not only diminished proinflammatory cytokine secretion but also enhanced anti-inflammatory protein release (P < 0.05). Our data suggest that Notch1R plays a pivotal role in M(1) macrophage differentiation and heightened inflammatory responses. Therefore, we conclude that inhibition of Notch1R and subsequent downstream signaling enhances monocyte to M(2) polarized macrophage outcomes and promotes anti-inflammatory mediation during cellular stress

Factors Released From Embryonic Stem Cells Stimulate C-Kit-Flk-1 \u3csup\u3e+Ve\u3c/sup\u3e Progenitor Cells And Enhance Neovascularization

We examined whether factors released from embryonic stem (ES) cells inhibit cardiac and vascular cell apoptosis and stimulate endogenous progenitor cells that enhance neovascularization with improved cardiac function. We generated and transplanted ES-conditioned medium (CM) in the infarcted heart to examine effects on cardiac and vascular apoptosis, activation of endogenous c-kit and FLK-1+ve cells, and their role in cardiac neovascularization. TUNEL, caspase-3 activity, immunohistochemistry, H&E, and Masson\u27s trichrome stains were used to determine the effect of transplanted ES-CM on cardiac apoptosis and neovascularization. TUNEL staining and caspase-3 activity confirm significantly (p\u3c0.05) reduced apoptosis in MI+ES-CM compared with MI+ cell culture medium. Immunohistochemistry demonstrated increased (p\u3c0.05, 53%) c-kit+ve and FLK-1+ve positive cells, as well as increased (p\u3c0.05, 67%) differentiated CD31-positive cells in ES-CM groups compared with respective controls. Furthermore, significantly (p\u3c0.05) increased coronary artery vessels were observed in ES-CM transplanted hearts compared with control. Heart function was significantly improved following ES-CM transplantation. Next, we observed significantly increased (p\u3c0.05) levels of c-kit activation proteins (HGF and IGF-1), anti-apoptosis factors (IGF-1 and total antioxidants), and neovascularization protein (VEGF). In conclusion, we suggest that ES-CM following transplantation in the infarcted heart inhibits apoptosis, activates cardiac endogenous c-kit and FLK-1+ve cells, and differentiates them into endothelial cells (ECs) that enhances neovascularization with improved cardiac function. © 2010 Mary Ann Liebert, Inc

Factors Released from Embryonic Stem Cells Stimulate c-kit-FLK-1+ve Progenitor Cells and Enhance Neovascularization

We examined whether factors released from embryonic stem (ES) cells inhibit cardiac and vascular cell apoptosis and stimulate endogenous progenitor cells that enhance neovascularization with improved cardiac function. We generated and transplanted ES-conditioned medium (CM) in the infarcted heart to examine effects on cardiac and vascular apoptosis, activation of endogenous c-kit and FLK-1+ve cells, and their role in cardiac neovascularization. TUNEL, caspase-3 activity, immunohistochemistry, H&E, and Masson's trichrome stains were used to determine the effect of transplanted ES-CM on cardiac apoptosis and neovascularization. TUNEL staining and caspase-3 activity confirm significantly (p < 0.05) reduced apoptosis in MI+ES-CM compared with MI+ cell culture medium. Immunohistochemistry demonstrated increased (p < 0.05, 53%) c-kit+ve and FLK-1+ve positive cells, as well as increased (p < 0.05, 67%) differentiated CD31-positive cells in ES-CM groups compared with respective controls. Furthermore, significantly (p < 0.05) increased coronary artery vessels were observed in ES-CM transplanted hearts compared with control. Heart function was significantly improved following ES-CM transplantation. Next, we observed significantly increased (p < 0.05) levels of c-kit activation proteins (HGF and IGF-1), anti-apoptosis factors (IGF-1 and total antioxidants), and neovascularization protein (VEGF). In conclusion, we suggest that ES-CM following transplantation in the infarcted heart inhibits apoptosis, activates cardiac endogenous c-kit and FLK-1+ve cells, and differentiates them into endothelial cells (ECs) that enhances neovascularization with improved cardiac function. Antioxid. Redox Signal. 13, 1857–1865

Fibroblast growth factor-9 enhances M2 macrophage differentiation and attenuates adverse cardiac remodeling in the infarcted diabetic heart.

Inflammation has been implicated as a perpetrator of diabetes and its associated complications. Monocytes, key mediators of inflammation, differentiate into pro-inflammatory M1 macrophages and anti-inflammatory M2 macrophages upon infiltration of damaged tissue. However, the inflammatory cell types, which propagate diabetes progression and consequential adverse disorders, remain unclear. The current study was undertaken to assess monocyte infiltration and the role of fibroblast growth factor-9 (FGF-9) on monocyte to macrophage differentiation and cardioprotection in the diabetic infarcted heart. Db/db diabetic mice were assigned to sham, myocardial infarction (MI), and MI+FGF-9 groups. MI was induced by permanent coronary artery ligation and animals were subjected to 2D transthoracic echocardiography two weeks post-surgery. Immunohistochemical and immunoassay results from heart samples collected suggest significantly increased infiltration of monocytes (Mean ± SEM; MI: 2.02% ± 0.23% vs. Sham 0.75% ± 0.07%; p<0.05) and associated pro-inflammatory cytokines (TNF-α, MCP-1, and IL-6), adverse cardiac remodeling (Mean ± SEM; MI: 33% ± 3.04% vs. Sham 2.2% ± 0.33%; p<0.05), and left ventricular dysfunction (Mean ± SEM; MI: 35.4% ± 1.25% vs. Sham 49.19% ± 1.07%; p<0.05) in the MI group. Importantly, treatment of diabetic infarcted myocardium with FGF-9 resulted in significantly decreased monocyte infiltration (Mean ± SEM; MI+FGF-9: 1.39% ± 0.1% vs. MI: 2.02% ± 0.23%; p<0.05), increased M2 macrophage differentiation (Mean ± SEM; MI+FGF-9: 4.82% ± 0.86% vs. MI: 0.85% ± 0.3%; p<0.05) and associated anti-inflammatory cytokines (IL-10 and IL-1RA), reduced adverse remodeling (Mean ± SEM; MI+FGF-9: 11.59% ± 1.2% vs. MI: 33% ± 3.04%; p<0.05), and improved cardiac function (Fractional shortening, Mean ± SEM; MI+FGF-9: 41.51% ± 1.68% vs. MI: 35.4% ± 1.25%; p<0.05). In conclusion, our data suggest FGF-9 possesses novel therapeutic potential in its ability to mediate monocyte to M2 differentiation and confer cardiac protection in the post-MI diabetic heart