Abstract 1228: Decreased Mitochondrial Biogenesis and Increased Pro-oxidant Activity Are Associated with Oxidative Impairment of Complex II in the Postischemic Heart

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Jingfeng Chen ◽  
Chwen-Lih Chen ◽  
Brian Palmer ◽  
Jay L Zweier ◽  
Yeong-Renn Chen

Increased O 2 ·− generated in mitochondria and NO is a key mechanism of cell death in the postischemic injury. Succinate ubiquinone reductase (SQR or Complex II) is a crucial segment of electron transport chain. Oxidative impairment of SQR has been observed in the postischemic myocardium. When rats are subjected to a 30 min coronary ligation, followed by a 24 h reperfusion, two polypeptides in tissue homogenate were found to react with the antibody against nuclear-encoded 29 kDa iron-sulfur protein (ISP) of SQR. One at 29 kDa corresponded to the mature form localized in mitochondria was present in normal amounts. The other with higher molecular weight 32 kDa corresponded to the precursor localized in cytosol was marked deficient. Similar results were observed when isolated heart was subjected to global ischemia (30min) and reperfusion (1h). Taken together, these results implicate mitochondria myopathy with an abnormality of biogenesis in the postischemic heart. The SQR mRNA level analyzed by quantitative real-time PCR was decreased 51%. Both mRNA and protein expressions of transcription coactivator PGC-1α were decreased in postischemic models 44% and 38% respectively, indicating a defect in the regulation and coordination of mitochondrial biogenesis. The mRNA levels of downstream transcription factors and antioxidant enzymes including NRF, TFAM, MnSOD, and UCP were similarly decreased; indicating that defect in mitochondrial biogenesis augments the oxidative stress in the postischemic heart. In addition, peroxynitrite formation was detected in the mitochondria of postischemic myocyte. The SQR isolated from myocardium was further used to study the interaction of NO with SQR in vitro . Under the conditions of enzyme turnover, SQR obtained after NO (25 fold excess) pretreatment gained catalytic function to generate hydroxyl radical detected by EPR spin trapping using DEPMPO. In the presence of catalase and iron chelator, the EPR signal of associated with DEPMPO/ · OH was completely abolished, suggesting the involvement of iron-H 2 O 2 dependent Fenton reaction. Direct EPR measurement at 77 °K indicated the formation of nonheme iron-NO complex, implying electron leakage to O 2 had occurred at the ISP of SQR and excess NO predisposed SQR to pro-oxidant activity.

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Jianjun Jiang ◽  
Yining Shi ◽  
Jiyu Cao ◽  
Youjin Lu ◽  
Gengyun Sun ◽  
...  

Abstract Background This study aimed to explore the effects of ceramide (Cer) on NLRP3 inflammasome activation and their underlying mechanisms. Methods Lipopolysaccharide (LPS)/adenosine triphosphate (ATP)-induced NLRP3 inflammasome activation in J774A.1 cells and THP-1 macrophages was used as an in vitro model of inflammation. Western blotting and real-time PCR (RT-PCR) were used to detect the protein and mRNA levels, respectively. IL-1β and IL-18 levels were measured by ELISA. ASM assay kit and immunofluorescence were used to detect ASM activity and Cer content. Results Imipramine, a well-known inhibitor of ASM, significantly inhibited LPS/ATP-induced activity of ASM and the consequent accumulation of Cer. Additionally, imipramine suppressed the LPS/ATP-induced expression of thioredoxin interacting protein (TXNIP), NLRP3, caspase-1, IL-1β, and IL-18 at the protein and mRNA level. Interestingly verapamil, a TXNIP inhibitor, suppressed LPS/ATP-induced activation of TXNIP/NLRP3 inflammasome but did not affect LPS/ATP-induced ASM activation and Cer formation. TXNIP siRNA and verapamil inhibited C2-Cer-induced upregulation of TXNIP and activation of the NLRP3 inflammasome. In addition, the pretreatment of cells with sulfo-N-succinimidyl oleate (SSO), an irreversible inhibitor of the scavenger receptor CD36, blocked Cer-induced upregulation of nuclear factor-κB (NF-κB) activity, TXNIP expression, and NLRP3 inflammasome activation. Inhibition of NF-κB activation by SN50 prevented Cer-induced upregulation of TXNIP and activation of the NLRP3 inflammasome but did not affect CD36 expression. Conclusion This study demonstrated that the ASM/Cer/TXNIP signaling pathway is involved in NLRP3 inflammasome activation. The results documented that the CD36-dependent NF-κB-TXNIP signaling pathway plays an essential role in the Cer-induced activation of NLRP3 inflammasomes in macrophages.


Reproduction ◽  
2011 ◽  
Vol 142 (4) ◽  
pp. 581-591 ◽  
Author(s):  
Claire Glister ◽  
Leanne Satchell ◽  
Phil G Knight

Evidence supports local roles for transforming growth factor β superfamily members including activins and bone morphogenetic proteins (BMP) in follicle development. Access of these ligands to signalling receptors is likely modulated by extracellular binding proteins (BP). In this study, we comparedex vivoexpression of four BPs (chordin, gremlin, noggin and follistatin) in granulosal (GC) and theca interna (TC) compartments of developing bovine antral follicles (1–18 mm). Effects of FSH and IGF on BMP and BP expression by cultured GC, and effects of LH and BMPs on BP expression by cultured TC were also examined. Follicular expression of all four BP transcripts was higher in GC than TC compartments (P<0.001) a finding confirmed by immunohistochemistry. Follicle category affected (P<0.01) gremlin and follistatin mRNA abundance, with a significant cell-type×follicle category interaction for chordin, follistatin and noggin. Noggin transcript abundance was lower (P<0.05) in GC of large ‘E-active’ than ‘E-inactive’ follicles while follistatin mRNA level was higher (P<0.01). FSH enhanced CYP19, FSHR, INHBA and follistatin by GC without affecting BMP or BMP–BP expression. IGF increased CYP19 and follistatin, reduced BMP4, noggin and gremlin but did not affect chordin orFSHRmRNA levels. LH increased TC androgen secretion but had no effect on BMP or BP expression. BMPs uniformly suppressed TC androgen production whilst increasing chordin, noggin and gremlin mRNA levels up to 20-fold (P<0.01). These findings support the hypothesis that extracellular BP, mostly from GC, contribute to the regulation of intrafollicular BMP/activin signalling. Enhancement of thecal BP expression by BMP implies an autoregulatory feedback role to prevent excessive signalling.


Blood ◽  
2012 ◽  
Vol 120 (16) ◽  
pp. 3336-3344 ◽  
Author(s):  
Anu Laitala ◽  
Ellinoora Aro ◽  
Gail Walkinshaw ◽  
Joni M. Mäki ◽  
Maarit Rossi ◽  
...  

AbstractAn endoplasmic reticulum transmembrane prolyl 4-hydroxylase (P4H-TM) is able to hydroxylate the α subunit of the hypoxia-inducible factor (HIF) in vitro and in cultured cells, but nothing is known about its roles in mammalian erythropoiesis. We studied such roles here by administering a HIF-P4H inhibitor, FG-4497, to P4h-tm−/− mice. This caused larger increases in serum Epo concentration and kidney but not liver Hif-1α and Hif-2α protein and Epo mRNA levels than in wild-type mice, while the liver Hepcidin mRNA level was lower in the P4h-tm−/− mice than in the wild-type. Similar, but not identical, differences were also seen between FG-4497–treated Hif-p4h-2 hypomorphic (Hif-p4h-2gt/gt) and Hif-p4h-3−/− mice versus wild-type mice. FG-4497 administration increased hemoglobin and hematocrit values similarly in the P4h-tm−/− and wild-type mice, but caused higher increases in both values in the Hif-p4h-2gt/gt mice and in hematocrit value in the Hif-p4h-3−/− mice than in the wild-type. Hif-p4h-2gt/gt/P4h-tm−/− double gene-modified mice nevertheless had increased hemoglobin and hematocrit values without any FG-4497 administration, although no such abnormalities were seen in the Hif-p4h-2gt/gt or P4h-tm−/− mice. Our data thus indicate that P4H-TM plays a role in the regulation of EPO production, hepcidin expression, and erythropoiesis.


1997 ◽  
Vol 82 (6) ◽  
pp. 1926-1931 ◽  
Author(s):  
Nobuharu Fujii ◽  
Takeshi Shibata ◽  
Sachiko Homma ◽  
Haruo Ikegami ◽  
Kazuo Murakami ◽  
...  

Fujii, Nobuharu, Takeshi Shibata, Sachiko Homma, Haruo Ikegami, Kazuo Murakami, and Hitoshi Miyazaki. Exercise-induced changes in β-adrenergic-receptor mRNA level measured by competitive RT-PCR. J. Appl. Physiol. 82(6): 1926–1931, 1997.—Competitive reverse transcription-polymerase chain reaction (RT-PCR) analysis was used to clarify whether dynamic exercise-induced increases in β-adrenergic-receptor (β-AR) number in human lymphocytes are accompanied by increases in the β-AR mRNA level. Sixteen healthy subjects performed cycle ergometry until exhaustion. Before and immediately after exercise, peripheral blood was drawn from a forearm vein for preparation of lymphocytes. Both the β-AR mRNA level and the β-AR number were significantly increased by exercise. The changes in β-AR mRNA level and β-AR number were significantly correlated ( r = 0.63, P < 0.01). This finding suggests that a rapid increase in β-AR mRNA level might be an early adaptive response of the sympathetic nervous system to dynamic exercise. In vitro incubation of lymphocytes with epinephrine had no effect on β-AR mRNA levels, nor did adenosine 3′,5′-cyclic monophosphate, protein kinase C, or intracellular Ca2+ increase the β-AR mRNA level in vitro. Therefore, it appears that other mechanisms underlie the exercise-induced elevation of β-AR mRNA levels in human lymphocytes.


Blood ◽  
1990 ◽  
Vol 76 (6) ◽  
pp. 1150-1157 ◽  
Author(s):  
AR Migliaccio ◽  
G Migliaccio ◽  
M Brice ◽  
P Constantoulakis ◽  
G Stamatoyannopoulos ◽  
...  

Abstract We have studied the effects of recombinant hematopoietic growth factors, granulocyte-macrophage colony-stimulating factor (GM-CSF) and/or interleukin-3 (IL-3) on the globin program of adult human erythroid progenitors (BFUe) stimulated to terminal differentiation by erythropoietin under fetal bovine serum (FBS)-supplemented or FBS- deprived culture conditions. Fetal globin production by BFUe-derived erythroblasts was assessed at the protein and mRNA level and its cellular distribution was evaluated by immunofluorescence. Although hemoglobinization and maturation of BFUe-derived erythroblasts was by and large comparable in FBS-replete versus FBS-deprived cultures, the latter had significantly less (up to 20-fold) gamma-globin and gamma- globin mRNA levels. Reduced gamma-globin in serum-deprived cultures was also reflected by a smaller proportion of erythroblasts with detectable gamma-globin by immunofluorescence. Erythroid bursts induced by either GM-CSF or IL-3 produced similar levels of gamma-globin both in FBS- supplemented and in FBS-deprived cultures. These results, obtained even in cultures of highly enriched BFUe, suggest that GM-CSF and IL-3, although they significantly increase the number and size of erythroid bursts, do not by themselves exert a direct influence on the level of fetal globin synthesis. By contrast, factor(s) present in FBS appear to exert a dominant influence on fetal globin synthesis in vitro. Although FBS-deprived conditions appear to largely abrogate the in vitro activation of fetal hemoglobin (Hb F) in normal samples, they do support increased Hb F production in samples from patients with hereditary persistence of fetal hemoglobin or from cord blood.


Nutrients ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3727
Author(s):  
Petey W. Mumford ◽  
Shelby C. Osburn ◽  
Carlton D. Fox ◽  
Joshua S. Godwin ◽  
Michael D. Roberts

There is evidence in rodents to suggest that theacrine-based supplements modulate tissue sirtuin activity as well as other biological processes associated with aging. Herein, we examined if a theacrine-based supplement (termed NAD3) altered sirtuin activity in vitro while also affecting markers of mitochondrial biogenesis. The murine C2C12 myoblast cell line was used for experimentation. Following 7 days of differentiation, myotubes were treated with 0.45 mg/mL of NAD3 (containing ~2 mM theacrine) for 3 and 24 h (n = 6 treatment wells per time point). Relative to control (CTL)-treated cells, NAD3 treatments increased (p < 0.05) Sirt1 mRNA levels at 3 h, as well as global sirtuin activity at 3 and 24 h. Follow-up experiments comparing 24 h NAD3 or CTL treatments indicated that NAD3 increased nicotinamide phosphoribosyltransferase (NAMPT) and SIRT1 protein levels (p < 0.05). Cellular nicotinamide adenine dinucleotide (NAD+) levels were also elevated nearly two-fold after 24 h of NAD3 versus CTL treatments (p < 0.001). Markers of mitochondrial biogenesis were minimally affected. Although these data are limited to select biomarkers in vitro, these preliminary findings suggest that a theacrine-based supplement can modulate select biomarkers related to NAD+ biogenesis and sirtuin activity. However, these changes did not drive increases in mitochondrial biogenesis. While promising, these data are limited to a rodent cell line and human muscle biopsy studies are needed to validate and elucidate the significance of these findings.


2004 ◽  
Vol 08 (01) ◽  
pp. 1-12 ◽  
Author(s):  
Andrea L. Clark ◽  
Linda Mills ◽  
David A Hart ◽  
Walter Herzog

Mechanical loading of articular cartilage affects the synthesis and degradation of matrix macromolecules. Much of the work in this area has involved mechanical loading of articular cartilage explants or cells in vitro and assessing biological responses at the mRNA and protein levels. In this study, we developed a new experimental technique to load an intact patellofemoral joint in vivo using muscle stimulation. The articular cartilages were cyclically loaded for one hour in a repeatable and measurable manner. Cartilage was harvested from central and peripheral regions of the femoral groove and patella, either immediately after loading or after a three hour recovery period. Total RNA was isolated from the articular cartilage and biological responses were assessed on the mRNA level using the reverse transcriptase-polymerase chain reaction. Articular cartilage from intact patellofemoral joints demonstrated heterogeneity at the mRNA level for six of the genes assessed independent of the loading protocol. Cyclical loading of cartilage in its native environment led to alterations in mRNA levels for a subset of molecules when assessed immediately after the loading period. However, the increases in TIMP-1 and decreases in bFGF mRNA levels were transient; being present immediately after load application but not after a three hour recovery period.


Blood ◽  
1990 ◽  
Vol 76 (6) ◽  
pp. 1150-1157 ◽  
Author(s):  
AR Migliaccio ◽  
G Migliaccio ◽  
M Brice ◽  
P Constantoulakis ◽  
G Stamatoyannopoulos ◽  
...  

We have studied the effects of recombinant hematopoietic growth factors, granulocyte-macrophage colony-stimulating factor (GM-CSF) and/or interleukin-3 (IL-3) on the globin program of adult human erythroid progenitors (BFUe) stimulated to terminal differentiation by erythropoietin under fetal bovine serum (FBS)-supplemented or FBS- deprived culture conditions. Fetal globin production by BFUe-derived erythroblasts was assessed at the protein and mRNA level and its cellular distribution was evaluated by immunofluorescence. Although hemoglobinization and maturation of BFUe-derived erythroblasts was by and large comparable in FBS-replete versus FBS-deprived cultures, the latter had significantly less (up to 20-fold) gamma-globin and gamma- globin mRNA levels. Reduced gamma-globin in serum-deprived cultures was also reflected by a smaller proportion of erythroblasts with detectable gamma-globin by immunofluorescence. Erythroid bursts induced by either GM-CSF or IL-3 produced similar levels of gamma-globin both in FBS- supplemented and in FBS-deprived cultures. These results, obtained even in cultures of highly enriched BFUe, suggest that GM-CSF and IL-3, although they significantly increase the number and size of erythroid bursts, do not by themselves exert a direct influence on the level of fetal globin synthesis. By contrast, factor(s) present in FBS appear to exert a dominant influence on fetal globin synthesis in vitro. Although FBS-deprived conditions appear to largely abrogate the in vitro activation of fetal hemoglobin (Hb F) in normal samples, they do support increased Hb F production in samples from patients with hereditary persistence of fetal hemoglobin or from cord blood.


2004 ◽  
Vol 286 (5) ◽  
pp. C1053-C1061 ◽  
Author(s):  
Damien Freyssenet ◽  
Isabella Irrcher ◽  
Michael K. Connor ◽  
Martino Di Carlo ◽  
David A. Hood

Cytochrome c expression and mitochondrial biogenesis can be invoked by elevated intracellular Ca2+ in muscle cells. To characterize the potential role of Ca2+ as a messenger involved in mitochondrial biogenesis in muscle, we determined the effects of the Ca2+ ionophore A-23187 on the expression of nuclear- and mitochondrially encoded genes. Treatment of myotubes with 1 μM A-23187 for 48–96 h increased nuclear-encoded β-subunit F1ATPase and malate dehydrogenase (MDH) mRNA levels by 50–100% ( P < 0.05) but decreased mRNA levels of glutamate dehydrogenase (GDH) by 19% ( P < 0.05). mRNA levels of the cytochrome c oxidase (COX) nuclear-encoded subunits IV, Vb, and VIc were unchanged, whereas the mitochondrially encoded subunits COX II and COX III were decreased by 30 and 70%, respectively ( P < 0.05). This was paralleled by a 20% decrease ( P < 0.05) in COX activity. These data suggest that cytoplasmic Ca2+ differentially regulates the mRNA level of nuclear and mitochondrial genes. The decline in COX II and III mRNA may be mediated by Tfam, because A-23187 modestly reduced Tfam levels by 48 h. A-23187 induced time-dependent increases in Egr-1 mRNA, along with the activation of ERK1/2 and AMP-activated protein kinase. MEK inhibition with PD-98059 attenuated the increase in Egr-1 mRNA. A-23187 also increased Egr-1, serum response factor, and Sp1 protein expression, transcription factors implicated in mitochondrial biogenesis. Egr-1 overexpression increased nuclear-encoded cytochrome c transcriptional activation by 1.5-fold ( P < 0.05) and reduced GDH mRNA by 37% ( P < 0.05) but had no effect on MDH or β-subunit F1ATPase mRNA. These results indicate that changes in intracellular Ca2+ can modify mitochondrial phenotype, in part via the involvement of Egr-1.


2001 ◽  
Vol 170 (3) ◽  
pp. 513-520 ◽  
Author(s):  
G Aust ◽  
M Steinert ◽  
C Boltze ◽  
S Kiessling ◽  
C Simchen

Thyroid glands affected by Graves' disease (GD) show striking leukocytic infiltration, mainly by T-cells. The mechanisms by which the various leukocytes are maintained in the thyroid are unknown. Growth-regulated oncogene-alpha (GRO-alpha) in interaction with its receptor CXCR2 is a chemoattractant for both T-cells and neutrophils and may be one of the chemokines involved in the cell maintenance. GRO-alpha and CD18 mRNA as a marker of leukocytic infiltration were quantified in thyroid tissue using competitive RT-PCR. We found very high GRO-alpha mRNA levels in all thyroid tissues. In GD patients (n=16), the GRO-alpha mRNA did not correlate with the CD18 mRNA level or thyroid peroxidase and TSH-receptor antibodies in patients' sera. In thyroid autonomy (n=10), the GRO-alpha mRNA levels were significantly lower in autonomous single adenomas compared with the corresponding normal tissue. In order to define the cellular source of GRO-alpha mRNA and protein, we examined various thyroid-derived cells. Thyrocytes, thyroid-derived leukocytes and fibroblasts showed basal GRO-alpha mRNA and protein expression, which was remarkably upregulated by different stimuli in vitro. The expression of GRO-alpha by thyroid carcinoma cell lines confirms that thyrocytes may actually produce GRO-alpha. As shown by flow cytometry and immunohistology, CD68+ monocytes/macrophages are the only cell population strongly expressing CXCR2 in the thyroid.


Sign in / Sign up

Export Citation Format

Share Document