Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Key pathway”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7Linked to original sources
PubMed2003

Vitamin D analogs--drug design based on proteins involved in vitamin D signal transduction.

Vitamin D analogs have proven to be very valuable tools for the treatment of calcium-related diseases and certain hyperproliferative conditions such as renal osteodystrophy, psoriasis and cancer. In general, vitamin D analogs exploit the enzymic and receptor machinery of the 1alpha,25-dihydroxyvitamin D(3) (1alpha,25(OH)(2)D(3)) signal transduction pathway. Key proteins in this cascade include the vitamin D receptor (VDR), the vitamin D-binding protein (DBP) and three cytochrome P450s (CYP27A, CYP27B and CYP24) which effect the synthesis and breakdown of the natural hormone, 1alpha,25(OH)(2)D(3). Analogs have been designed which reduce or enhance the importance of each of these proteins in the signal transduction pathway. Vitamin D prodrugs require one or more steps of activation and overcome congenital or acquired blocks in the 1alpha-hydroxylation step. By far the biggest class of vitamin D analogs are the VDR agonists which directly mimic 1alpha,25(OH)(2)D(3) and trigger protein conformational changes in the receptor which lead to changes in the transcriptional machinery at vitamin D-responsive genes. Other emerging classes of molecules include the VDR antagonists and CYP24 inhibitors which target different events in the cascade. This review assesses the relative importance of each of the proteins of the vitamin D cascade, evaluates the success of these modifications in tailoring drugs in all classes for selected disease states and contemplates future directions for the field.

Animals↗
PubMed1997

Reexamination of the Intracellular Localization of de Novo Purine Synthesis in Cowpea Nodules.

Sucrose and Percoll density gradient centrifugation were used to separate organelles from the central zone tissue of cowpea (Vigna unguiculata L. Walp. cv Vita 3: Bradyrhizobium strain CB 756) nodules. Enzyme activity analysis has shown that both plastids and mitochondria have a full complement of enzymes for de novo purine synthesis. In vitro activities of individual component enzymes (glycinamide ribonucleotide synthetase, EC 6.3.4.13; glycinamide ribonucleotide transformylase, EC 2.1.2.2; aminoimidazole ribonucleotide synthetase, EC 6.3.3.1; aminoimidazole carboxamide ribonucleotide transformylase, EC 6.3.2.6; and adenylosuccinate-AMP lyase, EC 4.3.2.2) as well as of the whole purine pathway (from ribose-5-phosphate to inosine monophosphate) were similar in the two organelles. No significant cytosolic or bacteroidal activity of any of the purine pathway enzymes was detected on assay. These findings are contrary to earlier studies (M.J. Boland, K.R. Schubert [1983] Arch Biochem Biophys 220: 179-187; B.J. Shelp C.A. Atkins, P.J. Storer, D.T. Canvin [1983] Arch Biochem Biophys 224: 429-441) that concluded that enhanced expression of purine synthesis in nodules of ureide-forming species is localized to plastids. Significantly increased recovery of activity of key pathway enzymes (particularly of labile aminoimidazole ribonucleotide synthetase) coupled with improved assay methods and the use of Percoll in addition to sucrose for gradient centrifugation have together contributed to much higher reaction rates and more definitive analyses of particulate fractions.

Journal Article↗
PubMed2006

Characterization of a novel protein kinase D: Caenorhabditis elegans DKF-1 is activated by translocation-phosphorylation and regulates movement and growth in vivo.

Protein kinase D (PKD) isoforms are protein kinase C (PKC) effectors in diacylglycerol (DAG)-regulated signaling pathways. Key physiological processes are placed under DAG control by the distinctive substrate specificity and intracellular distribution of PKDs. Comprehension of the roles of PKDs in homeostasis and signal transduction requires further knowledge of regulatory interplay among PKD and PKC isoforms, analysis of PKC-independent PKD activation, and characterization of functions controlled by PKDs in vivo. Caenorhabditis elegans and mammals share conserved signaling mechanisms, molecules, and pathways Thus, characterization of the C. elegans PKDs could yield insights into regulation and functions that apply to all eukaryotic PKDs. C. elegans DKF-1 (D kinase family-1) contains tandem DAG binding (C1) modules, a PH (pleckstrin homology) domain, and a Ser/Thr protein kinase segment, which are homologous with domains in classical PKDs. DKF-1 and PKDs have similar substrate specificities. Phorbol 12-myristate 13-acetate (PMA) switches on DKF-1 catalytic activity in situ by promoting phosphorylation of a single amino acid Thr(588) in the activation loop. DKF-1 phosphorylation and activation are unaffected when PKC activity is eliminated by inhibitors. Both phosphorylation and kinase activity of DKF-1 are extinguished by substituting Ala for Thr(588) or Gln for Lys(455) ("kinase dead") or incubating with protein phosphatase 2C. Thus, DKF-1 is a PMA-activated, PKC-independent D kinase. In vivo, dkf-1 gene promoter activity is evident in neurons. Both dkf-1 gene disruption (null phenotype) and RNA interference-mediated depletion of DKF-1 protein cause lower body paralysis. Targeted DKF-1 expression corrected this locomotory defect in dkf-1 null animals. Supraphysiological expression of DKF-1 limited C. elegans growth to approximately 60% of normal length.

Amino Acid Sequence↗
PubMed2006

The fatty acid oxidation pathway as a therapeutic target for insulin resistance.

It is recognised that obesity is a major driver for insulin resistance and Type 2 diabetes in both adult and young members of diverse societies. Weight loss strategies involving diet, exercise and behaviour modification work only for the minority of highly motivated individuals, but fail completely in the vast majority; yet weight loss is associated with benefits in metabolic health. Why is it so difficult to maintain weight loss in the longer term? Here, the authors explore the possibility that energy partitioning, especially of lipids, plays a key role in both weight recidivism and, by association, insulin resistance. Drug targets that address key pathways important in this process, where progress in drug discovery is apparent, are discussed.

Animals↗
PubMed2000

Fibroblast biology. Role of synovial fibroblasts in the pathogenesis of rheumatoid arthritis.

There is growing evidence that activated synovial fibroblasts, as part of a complex cellular network, play an important role in the pathogenesis of rheumatoid arthritis. In recent years, significant progress has been made in elucidating the specific features of these fibroblasts. It has been understood that although macrophage and lymphocyte secreted factors contribute to their activation, rheumatoid arthritis synovial fibroblasts (RA-SFs) do not merely respond to stimulation by pro-inflammatory cytokines, but show a complex pattern of molecular changes also maintained in the absence of external stimulation. This pattern of activation is characterized by alterations in the expression of regulatory genes and signaling cascades, as well as changes in pathways leading to apoptosis. These together result in the upregulation of adhesion molecules that mediate the attachment of RA-SFs to the extracellular matrix and in the overexpression of matrix degrading enzymes that mediate the progressive destruction of the joints. In addition, activated RA-SFs exert specific effects on other cell types such as macrophages and lymphocytes. While the initiating step in the activation of RA-SFs remains elusive, several key pathways of RA-SF activation have been identified. However, there is so far no single, specific marker for this phenotype of RA-SF. It appears that activated RA-SFs are characterized by a set of specific properties which together lead to their aggressive behavior.

Animals↗
PubMed2026

Common Molecular Mechanisms and Candidate Drug Targets in Type 2 Diabetes Mellitus and Atherosclerotic Cardiovascular Disease.

This study examined the mechanisms underlying the comorbidity between type 2 diabetes mellitus (T2DM) and atherosclerotic cardiovascular disease (ASCVD), while identifying potential therapeutic targets. Common differentially expressed genes (C-DEGs) between T2DM and ASCVD were extracted from the GSE78721 and GSE12288 datasets. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses, protein-protein interaction (PPI) network construction, hub gene identification, and Drug-Gene Interaction Database (DGIdb) analysis were conducted. The association between hub C-DEGs and immune-infiltrating cells was analyzed using the CIBERSORT method. Expression levels of hub C-DEGs were quantified through qRT-PCR and Western blot analyses. A total of 32 C-DEGs were identified, comprising 20 upregulated and 12 downregulated genes. C-DEGs were predominantly enriched in key pathways, including viral myocarditis, arrhythmogenic right ventricular cardiomyopathy, hypertrophic cardiomyopathy, and dilated cardiomyopathy. PPI analysis revealed 29 nodes and 39 edges, leading to the identification of eight hub C-DEGs (HSP90B1, PLAU, SLPI, TOP3A, NCF4, PRF1, TUBA1C, and CS) across both datasets. Furthermore, hub C-DEGs (TOP3A, SLPI, NCF4, PRF1, and PLAU) demonstrated significant correlations with immune-infiltrating cell levels. Drugs specifically targeting these hub C-DEGs present promising candidates for the treatment of T2DM and ASCVD. Additionally, the expression of hub C-DEGs at both mRNA and protein levels was validated in patients with T2DM and ASCVD. An integrated bioinformatics analysis facilitated the screening of candidate therapeutic targets, mechanisms, and drugs for T2DM and ASCVD, offering new insights into molecular therapies for these conditions.

Diabetes Mellitus, Type 2↗
PubMed2026

Phase 3 Trial of Oral Infigratinib in Children with Achondroplasia.

BACKGROUND: Achondroplasia is a genetic skeletal condition caused by FGFR3 pathogenic variants. Infigratinib, an oral FGFR1-3 tyrosine kinase inhibitor, down-regulates key pathways in the pathogenesis of achondroplasia. METHODS: In this phase 3, multicenter, double-blind, placebo-controlled trial, we randomly assigned children with achondroplasia (3 to 17 years of age) in a 2:1 ratio to receive infigratinib (at a dose of 0.25 mg per kilogram of body weight) or placebo once daily for 52 weeks. The primary end point was the change from baseline in the annualized height velocity in the infigratinib group as compared with the placebo group at week 52. Key secondary end points were the change from baseline in the height z score and in the upper-to-lower body segment ratio at week 52. The primary analysis evaluated the treatment effect at week 52 in the full analysis population, with missing data handled with a prespecified imputation approach. RESULTS: In all, 114 patients underwent randomization: 75 patients to receive infigratinib (with 1 withdrawal before treatment) and 39 patients to receive placebo. The difference between infigratinib and placebo in the least-squares mean change from baseline to week 52 was 1.74 cm per year (95% confidence interval [CI], 1.31 to 2.17; P<0.001) for the annualized height velocity, 0.32 (96% CI, 0.23 to 0.41; P<0.001) for the height z score, and -0.02 (96% CI, -0.06 to 0.01) for the upper-to-lower body segment ratio. Adverse events occurred in 71 of 74 patients (96%) in the infigratinib group and in 37 of 39 patients (95%) in the placebo group; serious adverse events occurred in 4 of 74 patients (5%) and 1 of 39 patients (3%), respectively. No serious adverse events or adverse events leading to treatment discontinuation were considered by the investigator to be related to infigratinib or placebo. CONCLUSIONS: In children with achondroplasia, treatment with once-daily oral infigratinib for 52 weeks resulted in a significantly greater increase from baseline in the annualized height velocity than placebo. (Funded by BridgeBio Pharma; PROPEL 3 ClinicalTrials.gov number, NCT06164951; EudraCT number, 2023-506130-67.).

Adolescent↗
PubMed2005

Precocious metamorphosis in transgenic silkworms overexpressing juvenile hormone esterase.

Insect growth and development are intricately regulated by the titers of juvenile hormones (JHs) and ecdysteroids (and/or their metabolites) in the insect hemolymph. Hydrolysis of the methyl ester of JH by a JH-specific esterase (JHE) is a key pathway for the degradation of JH. Here, we generate transgenic silkworm strains that overexpress JHE by using the binary GAL4/UAS system. Overexpression of JHE from the embryonic stage resulted in larval-pupal metamorphosis after the third stadium, two stadia earlier than that observed in wild-type insects. This precocious metamorphosis suggests that JHs are not critical for normal development of embryo or larva before the second molt in Lepidoptera (moths and butterflies). Our transgenic approach allowed us to dissect the function of key physiological events that occur from embryogenesis. Until now, these types of studies were possible only in later larval stadia by using physical techniques such as allatectomy or the application of JH analogues. We believe that our system will allow further pioneering studies in insect physiology.

Animals↗
PubMed2026

Carrot Juice Intake Modulates Oncogenic and Inflammatory Pathways in Advanced Colorectal Adenomas: A Pilot Feasibility Study.

Carrots are a rich dietary source of carotenoids and polyacetylenes, bioactive compounds with demonstrated anti-inflammatory and anticancer properties in experimental models. Epidemiological evidence suggests that carrot consumption is associated with a reduced risk of colorectal cancer; however, clinical data linking carrot intake to molecular changes in premalignant colorectal tissue remain limited. In this pilot intervention study, 20 patients with advanced colorectal adenomas were enrolled. Fifteen participants consumed carrot juice daily for 21&#x2009;days, while five served as untreated controls. Paired adenoma biopsies were collected before and after the intervention and were analyzed using gene expression microarrays to assess transcriptional responses. Carrot juice intake was well tolerated, with adherence exceeding 95% and no reported adverse events. Transcriptomic analysis revealed modulation of key pathways implicated in colorectal carcinogenesis, including downregulation of the WNT, PI3K-AKT, and MAPK signaling pathways, as well as cyclooxygenase-2-related inflammatory pathways and cytokine signaling. These changes were consistent with reduced oncogenic signaling and attenuation of inflammatory activity within adenoma tissue. In summary, short-term carrot juice consumption was associated with coordinated suppression of molecular pathways involved in colorectal adenoma progression. These findings provide preliminary clinical evidence that a whole-food dietary intervention may influence early carcinogenic processes and support the need for larger controlled studies evaluating clinical outcomes.

Journal Article↗
PubMed2001

An integrated hypothesis that considers drusen as biomarkers of immune-mediated processes at the RPE-Bruch's membrane interface in aging and age-related macular degeneration.

Age-related macular degeneration (AMD) is a blinding disease that afflicts millions of adults in the Western world. Although it has been proposed that a threshold event occurs during normal aging which leads to AMD, the sequelae of biochemical, cellular, and/or molecular events leading to the development of AMD are poorly understood. Although available data provide strong evidence that a significant proportion of AMD has a genetic basis, no gene(s) has yet been identified that causes a significant proportion of AMD. Moreover, no major molecular pathways involved in the etiology of this disease have been elucidated.Drusen, pathological deposits that form between the retinal pigmented epithelium (RPE) and Bruch's membrane, are significant risk factors for the development of AMD. In our view, the development of testable new hypotheses of drusen origins has been hindered significantly by the absence of a comprehensive profile of their molecular composition. In this review, we describe an integrated ultrastructural, histochemical, molecular biological, and biochemical approach to identify specific molecular pathways associated with drusen biogenesis. The implicit assumption underlying these recent investigations has been that a thorough understanding of the composition of drusen and source(s) of drusen-associated material is likely to provide fresh insight into the pathobiology underlying AMD. Significantly, these studies have revealed that proteins associated with inflammation and immune-mediated processes are prevalent among drusen-associated constituents. Transcripts that encode a number of these molecules have been detected in retinal, RPE, and choroidal cells. These data have also lead to the observations that dendritic cells, potent antigen-presenting cells, are intimately associated with drusen development and that complement activation is a key pathway that is active both within drusen and along the RPE-choroid interface. We propose herein a unifying hypothesis of drusen biogenesis that attempts to incorporate a large body of new and previously published structural, histochemical, and molecular data pertaining to drusen composition and development. This theory is put forth with the acknowledgment that numerous AMD genotypes may exist. Thus, only some aspects of the proposed hypothesis may be involved in any given AMD genotype. Importantly, this hypothesis invokes, for the first time, the potential for a direct role of cell- and immune-mediated processes in drusen biogenesis. We acknowledge that the proposed hypothesis clearly represents a paradigm shift in our conceptualization pertaining to pathways that participate in the development of drusen and age-related macular degeneration. It is our hope that other investigators will test, validate and/or refute various aspects of this hypothesis, and in so doing, increase our overall understanding of the biological pathways associated with early AMD.

Aging↗
PubMed2005

Regulation of bidirectional melanosome transport by organelle bound MAP kinase.

Regulation of intracellular transport plays a role in a number of processes, including mitosis, determination of cell polarity, and neuronal growth. In Xenopus melanophores, transport of melanosomes toward the cell center is triggered by melatonin, whereas their dispersion throughout the cytoplasm is triggered by melanocyte-stimulating hormone (MSH), with both of these processes mediated by cAMP-dependent protein kinase A (PKA) activity [1, 2]. Recently, the ERK (extracellular signal-regulated kinase) pathway has been implicated in regulating organelle transport and signaling downstream of melatonin receptor [3, 4]. Here, we directly demonstrate that melanosome transport is regulated by ERK signaling. Inhibition of ERK signaling by the MEK (MAPK/ERK kinase) inhibitor U0126 blocks bidirectional melanosome transport along microtubules, and stimulation of ERK by constitutively active MEK1/2 stimulates transport. These effects are specific because perturbation of ERK signaling has no effect on the movement of lysosomes, organelles related to melanosomes [5]. Biochemical analysis demonstrates that MEK and ERK are present on melanosomes and transiently activated by melatonin. Furthermore, this activation correlates with an increase in melanosome transport. Finally, direct inhibition of PKA transiently activates ERK, demonstrating that ERK acts downstream of PKA. We propose that signaling of organelle bound ERK is a key pathway that regulates bidirectional, microtubule-based melanosome transport.

Animals↗
PubMed2006

A CK2-dependent mechanism for degradation of the PML tumor suppressor.

The PML tumor suppressor controls key pathways for growth suppression, induction of apoptosis, and cellular senescence. PML loss occurs frequently in human tumors through unknown posttranslational mechanisms. Casein kinase 2 (CK2) is oncogenic and frequently upregulated in human tumors. Here we show that CK2 regulates PML protein levels by promoting its ubiquitin-mediated degradation dependent on direct phosphorylation at Ser517. Consequently, PML mutants that are resistant to CK2 phosphorylation display increased tumor-suppressive functions. In a faithful mouse model of lung cancer, we demonstrate that Pml inactivation leads to increased tumorigenesis. Furthermore, CK2 pharmacological inhibition enhances the PML tumor-suppressive property in vivo. Importantly, we found an inverse correlation between CK2 kinase activity and PML protein levels in human lung cancer-derived cell lines and primary specimens. These data identify a key posttranslational mechanism that controls PML protein levels and provide therapeutic means toward PML restoration through CK2 inhibition.

Amino Acid Sequence↗
PubMed2006

Activation of cyclic AMP pathway prevents CD34(+) cell apoptosis.

OBJECTIVE: Although cAMP is involved in a number of physiologic functions, its role in hematopoietic cell fate decision remains poorly understood. We have recently demonstrated that in CD34(+)-derived megakaryocytes, cAMP-related agents prevent apoptosis. In this study we addressed the question of whether cAMP also regulates survival of their precursors, CD34(+) cells. METHODS: Apoptosis was evaluated by fluorescence microscopy, and detection of hypodiploid or annexin V(+) cells by flow cytometry. Mitochondrial membrane potential and bcl-xL or caspase-3 expression were assessed by flow cytometry. Colony-forming units were studied by clonogenic assays in methylcellulose. RESULTS: We found that two different cAMP analogs such as Dibutiril-cAMP and sp-5,6-DCl-BIMPS (BIMPS) promoted survival of human umbilical cord-derived CD34(+) cells by suppressing apoptosis induced by either nitric oxide (NO) or serum deprivation. Involvement of PKA and PI3K pathway was demonstrated by the ability of their specific inhibitors Rp-cAMP and Wortmannin or LY294002 respectively to reverse the antiapoptotic effect of BIMPS. Treatment of CD34(+) cell with BIMPS not only restrained the bcl-xL downregulation but also suppressed the loss of mitochondrial membrane potential and caspase-3 activation induced by serum starvation. While thrombopoietin (TPO), granulocyte colony-stimulating factor (G-CSF) or stem cell factor (SCF) were not able to increase cAMP levels, the antiapoptotic activity exerted by these growth factors was blocked by inhibition of the adenylate cyclase and synergized by BIMPS. Cyclic AMP analogs suppressed the decreased colony formation in cells exposed to NO or serum deprivation. CONCLUSION: Altogether, our results strongly suggest that cAMP appears to be not only a key pathway controlling CD34(+) survival, but also a mediator of the TPO-, G-CSF- and SCF-mediated cytoprotection.

Antigens, CD34↗
PubMed2006

Metabolic insights into the hepatoprotective role of N-acetylcysteine in mouse liver.

The hepatoprotective mechanisms of N-acetylcysteine (NAC) in non-acetaminophen-induced liver injury have not been studied in detail. We investigated the possibility that NAC could affect key pathways of hepatocellular metabolism with or without changes in glutathione (GSH) synthesis. Hepatocellular metabolites and high-energy phosphates were quantified from mouse liver extracts by 1H- and 31P-NMR (nuclear magnetic resonance) spectroscopy. 13C-NMR-isotopomer analysis was used to measure [U-13C]glucose metabolism through pyruvate dehydrogenase (PDH) and pyruvate carboxylase (PC). NAC (150-1,200 mg/kg) increased liver concentrations of GSH from 8.60 +/- 0.48 to a maximum of 12.95 +/- 1.03 micromol/g ww, whereas hypotaurine (HTau) concentrations increased from 0.05 +/- 0.02 to 9.95 +/- 1.12 micromol/g ww. The limited capacity of NAC to increase GSH synthesis was attributed to impaired glucose metabolism through PC. However, 300 mg/kg NAC significantly increased the fractional 13C-enrichment in Glu (from 2.08% +/- 0.26% to 4.00% +/- 0.44%) synthesized through PDH, a key enzyme for mitochondrial energy metabolism. This effect could be uncoupled from GSH synthesis and was associated with the prevention of liver injury induced by tert-butylhydroperoxide and 3-nitropropionic acid. In conclusion, NAC (1) has a limited capacity to elevate GSH synthesis; (2) increases HTau formation linearly; and (3) improves mitochondrial tricarboxylic acid (TCA) cycle metabolism by stimulation of carbon flux through PDH. This latter effect is independent of the capacity of NAC to replete GSH stores. These metabolic actions, among other yet unknown effects, are critical for NAC's therapeutic value and should be taken into account when deciding on a wider use of NAC.

Acetylcysteine↗
PubMed2002

p14(ARF) regulates E2F activity.

The ARF protein product of the ink4a/arf locus is induced by a variety of oncogenic signals. ARF facilitates growth arrest through the p53 pathway by hindering the down-regulation of p53 activity mediated by MDM2, through the formation of a protein complex with MDM2. Here we have explored the possibility that human p14(ARF) activity is integrated with growth regulating pathways other than p53, and report our results that p14(ARF) can control the activity of the E2F transcription factor. p14(ARF) regulates E2F activity in different cell-types, including p53(-/-)/mdm(-/-) MEFs, thus excluding that the effects of p14(ARF) are indirectly caused through MDM2 modulation. p14(ARF) down-regulates E2F-dependent transcription, and in cells undergoing E2F-dependent apoptosis prompts cell cycle arrest. p14(ARF) possesses multiple binding domains for E2F-1, one of which resides within the N-terminal region and coincides with the regulation of E2F activity. A mutational analysis of p14(ARF) indicates that the E2F-1 and MDM2 binding domains can be distinguished. These results highlight the potential interplay between p14(ARF) and E2F, and establish p14(ARF) as a pleiotrophic regulator of cell growth that acts by targetting at least two key pathways in the control of proliferation, namely E2F and p53.

Animals↗
PubMed2005

Glutathione-S-transferase M1, obesity, statins, and autonomic effects of particles: gene-by-drug-by-environment interaction.

RATIONALE: Air pollution by particulate matter (PM) has been associated with cardiovascular deaths, although the mechanism of action is unclear. One proposed pathway is through disturbances of the autonomic control of the heart. OBJECTIVES: We tested the hypothesis that such disturbances are mediated by PM increasing oxidative stress by examining the association between PM and the high-frequency (HF) component of heart rate variability as modified by the presence or absence of the allele for glutathione-S-transferase M1 (GSTM1) and the use of statins, obesity, high neutrophil counts, higher blood pressure, and older age. METHODS: We examined the association between particles less than 2.5 microM in aerodiameter (PM2.5) and HF in 497 participants in the Normative Aging Study, using linear regression controlling for covariates. MAIN RESULTS: A 10-microg/m3 increase in PM2.5 during the 48 h before HF measurement was associated with a 34% decrease in HF, 95% confidence interval (-9%, -52%), in subjects without the allele, but had no effect in subjects with GSTM1 present. Among GSTM1-null subjects, the use of statins eliminated the effect of PM2.5. Obesity and high neutrophil counts also worsened the PM effects with or without GSTM1. CONCLUSION: The effects of PM2.5 on HF appear to be mediated by reactive oxygen species. This may be a key pathway for the adverse effects of combustion particles.

Age Factors↗
PubMed2003

Cardioplegic arrest induces apoptosis signal-pathway in myocardial endothelial cells and cardiac myocytes.

OBJECTIVE: Myocardial ischemia-reperfusion is associated with free radical-mediated injury and may be involved in cardiac apoptosis. The purpose of our study was to investigate (1) if cardioplegia-induced ischemia-reperfusion initiates cardiac apoptosis signal pathway, and (2) if this is mediated by free radicals. METHODS: We subjected 13 pigs (56+/-10 kg) to 1 h of cold crystalloid cardioplegic arrest (CA) on cardiopulmonary bypass (CPB), and collected five transmural LV biopsies: prior to CPB (baseline), at 60 min CA, at 15 and 30 min reperfusion on CPB, and at 120 min post CPB. Two additional pigs were subjected to CPB but not CA and two further pigs were neither subjected to CPB nor CA and served as sham-operated time controls. LV specimens were cut at 7 microm and immunocytochemically stained against active caspase-3 and 85 kDa poly(ADP-ribose) polymerase (PARP) as apoptosis signal-pathway key enzymes, nitrotyrosine as indicator for peroxynitrite (ONOO(-))-mediated tissue injury, and 8-iso-prostaglandin-F(2)alpha as indicator for oxygen free radical-mediated lipid peroxidation. Specimen were assessed using a scale of 0 (negative) to 3 (highly positive), and cardiomyocytes were quantitatively investigated using TV densitometry. RESULTS: At 60 min CA, caspase-3 was increased by 9.2+/-3.7 gray units and remained on this level until 2 h post CPB (P</=0.003 vs. baseline); nitrotyrosine increased over time to reach a maximum of +8.5+/-8.1 gray units at 120 min post CPB (P=0.016); and there was a trend for increased 8-iso-prostaglandin-F(2)alpha at 60 min CA (+3.6+/-4.7 gray units; P=0.089). At 60 min CA, 92% of the hearts showed active caspase-3, only 42% demonstrated nitrotyrosine formation, and 58% exhibited 8-iso-prostaglandin-F(2)alpha. At 120 min post CPB, most hearts positive for caspase-3 were also positive for nitrotyrosine (83%), and 8-iso-prostaglandin-F(2)alpha (75%), but no heart showed PARP cleavage. Hearts subjected to CPB but not CA as well as time controls remained negative for all variables. CONCLUSIONS: Our data show that CA initiates apoptosis signal-pathway in myocardial endothelium and myocytes; however, this did not result in apoptotic cell death as we did not find PARP cleavage. Further, the data suggest that CA-induced apoptosis signal pathway activation is not mediated by free radicals as caspase-3 activation preceded both nitrotyrosine and 8-iso-prostaglandin-F(2)alpha formation.

Animals↗
PubMed2005

Transfer pathways between the ovaries and the uterus in the cebus monkeys (Cebus apella).

The aim of this work was to study, in the Cebus apella monkey, the developmental changes in the microanatomy of the utero-ovarian ligament (UOL) and whether their vascular and neural elements might be involved in the transfer of signals between the ovaries and uterus. Sections including uterus, UOL, and ovary obtained from two foetuses, two prepubertal, and four cycling monkeys, two of them treated with a neuron-axonal tracer, diamidino yellow (DY) into the corpus luteum (CL) and the remaining two into the endometrium, were analyzed for the expression of neurofilament protein (NFP) and tracer distribution. Eight regularly cycling females were used to investigate the transfer to the CL of pulses of prostaglandin F(2alpha) (PGF(2alpha)) (n=4) or its vehicle (n=4) given intra-uterus. A convoluted artery, in conjunction with various vein channels, passed over the UOL allowing for a direct communication between uterus and ovaries. The artery acquired prominence during adulthood, in a manner well suited with the ovarian status. Immunohistochemical analysis revealed that NFP expression by the oocyte and by the endometrial epithelial cells was a highly conserved feature during development, whereas the appearance of NFP fibers in the ovaries, UOL, and uterus was a late event in the ontogenesis, likely regulated by the hormonal environment. Neurons, as an obvious source for these NFP fibers, were not recognized at any developmental stage, although some neuron-like cells were observed within the CL. The pattern displayed by the tracer DY, further suggested a reciprocal axonal transport among endometrial cells and follicular and luteal cells of both ovaries and between the ovaries themselves. The functionality of the utero-ovarian connection was assessed after injecting PGF(2alpha) intra-uterus. A short exposition to PGF(2alpha) pulses was required for lowering ovarian and peripheral progesterone concentrations causing luteolysis, indicating that transport mechanism operating between uterus and ovary must be very efficient. The results suggest that the vessels and axons contained in the UOL of the Capuchin monkeys might be two combined key pathways underlying the reciprocal transfer of signals controlling utero-ovarian homeostasis.

Amidines↗