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1.
Pediatr Qual Saf ; 8(5): e696, 2023.
Article in English | MEDLINE | ID: mdl-37818202

ABSTRACT

Introduction: The American Academy of Pediatrics recommends using isotonic intravenous fluids (IVF) for maintenance needs to decrease the risk of hyponatremia. We conducted a quality improvement project to increase the use of isotonic maintenance IVF in pediatric patients admitted to three sites in a community hospital network to >85% within 12 months. Methods: We used improvement methodology to identify causes of continued hypotonic fluid use, which involved provider behavior and systems factors. We implemented interventions to address these factors including: (1) education; (2) clinical decision support; and (3) stocking automated medication dispensing systems with isotonic IVF. We compared isotonic IVF use before and after interventions in all admitted patients aged 28 days to 18 years who received maintenance IVFs at the rate of at least 10 mL/hour. We excluded admissions of patients with active chronic medical conditions like diabetic ketoacidosis. Balancing measures were the occurrence of adverse events from hypo- or hypernatremia. Data were analyzed using Laney P' statistical process control charts. Results: Isotonic IVF use among patients requiring maintenance fluids at all three sites surpassed the goal of >85% within 12 months. There were no reports of hypo- or hypernatremia or other adverse outcomes related to the use of isotonic IVF. Conclusion: A combination of interventions aimed at provider behavior and systems factors was critical to successfully adopting the American Academy of Pediatrics guideline regarding the use of maintenance isotonic IVF in hospitalized children.

2.
J Vet Dent ; 40(4): 298-306, 2023 Dec.
Article in English | MEDLINE | ID: mdl-36987700

ABSTRACT

A retrospective cohort study to describe a novel use of a mechanically retained, rigid obturator (RO) to manage maxillary and mandibular persistent pathologic oral communications (PPOCs). This study included 22 horses with PPOC with at least 6 months of follow-up after treatment with a RO. The RO was made with a flowable, bis-acryl-based composite resin. Medical records were analyzed, including case details, obtained imaging, surgical reports, and follow-up information. There were 10 horses that had follow-up examinations by the authors and 8 horses by the referring veterinarian; in 4 horses, follow-up information was obtained by informal telephone interviews with the owner. Complete resolution of clinical signs was obtained in 21 of 22 (95.5%) horses, with confirmed healing of the PPOC in 15 of 22 (68.2%) horses. Complications were noted in 7 of 22 (31.8%) cases. Complications included: complete loss of RO (2 horses), fracture/defect of the RO (2 horses), displaced/shifted RO (1 horse), and incomplete seal of the PPOC (2 horses). All complications were resolved by repairing or replacing the RO. The RO placement is a successful, noninvasive, easily repeatable treatment for PPOC.


Subject(s)
Horse Diseases , Humans , Horses , Animals , Retrospective Studies , Horse Diseases/surgery , Tooth Extraction/veterinary
3.
Front Cell Infect Microbiol ; 11: 718213, 2021.
Article in English | MEDLINE | ID: mdl-34631600

ABSTRACT

Pseudomonas aeruginosa is a major opportunistic human pathogen which employs a myriad of virulence factors. In people with cystic fibrosis (CF) P. aeruginosa frequently colonises the lungs and becomes a chronic infection that evolves to become less virulent over time, but often adapts to favour persistence in the host with alginate-producing mucoid, slow-growing, and antibiotic resistant phenotypes emerging. Cysteamine is an endogenous aminothiol which has been shown to prevent biofilm formation, reduce phenazine production, and potentiate antibiotic activity against P. aeruginosa, and has been investigated in clinical trials as an adjunct therapy for pulmonary exacerbations of CF. Here we demonstrate (for the first time in a prokaryote) that cysteamine prevents glycine utilisation by P. aeruginosa in common with previously reported activity blocking the glycine cleavage system in human cells. Despite the clear inhibition of glycine metabolism, cysteamine also inhibits hydrogen cyanide (HCN) production by P. aeruginosa, suggesting a direct interference in the regulation of virulence factor synthesis. Cysteamine impaired chemotaxis, lowered pyocyanin, pyoverdine and exopolysaccharide production, and reduced the toxicity of P. aeruginosa secreted factors in a Galleria mellonella infection model. Thus, cysteamine has additional potent anti-virulence properties targeting P. aeruginosa, further supporting its therapeutic potential in CF and other infections.


Subject(s)
Pseudomonas Infections , Pseudomonas aeruginosa , Biofilms , Cysteamine , Glycine , Humans , Pseudomonas Infections/drug therapy , Virulence
4.
Cancer Chemother Pharmacol ; 88(3): 415-425, 2021 09.
Article in English | MEDLINE | ID: mdl-34043046

ABSTRACT

PURPOSE: Triple-negative breast cancer (TNBC) is an aggressive, lethal, heterogeneous type of breast cancer (BC). TNBC tends to have a lower response rate to chemotherapy and a lower 5-year survival rate than other types of BC due to recurrence and metastasis. Our previous study revealed that a combination of gemcitabine, romidepsin, and cisplatin was efficacious in controlling TNBC tumor development. In this study, we extended our investigation of gemcitabine + romidepsin + cisplatin in controlling TNBC tumor recurrence and metastasis. METHODS: We investigated the ability of gemcitabine + romidepsin + cisplatin to control cell survival and invasiveness using cell viability, soft agar colony formation, and transwell invasion assays. We determined the efficacy of gemcitabine + romidepsin + cisplatin in controlling tumor recurrence and metastasis using cell-derived xenograft animal models. We used immunoblotting to study signaling modulators regulated by gemcitabine + romidepsin + cisplatin in TNBC cells and tumor tissues. RESULTS: Treatment with gemcitabine + romidepsin + cisplatin reduced the TNBC MDA-MB231 and MDA-MB468 cell survival to ~ 50% and ~ 15%, as well as invasiveness to ~ 31% and ~ 13%, respectively. Gemcitabine + romidepsin + cisplatin suppressed modulators involved in epithelial-mesenchymal transition in an ROS-dependent manner. Controlling tumor recurrence, the Gem plus Rom + Cis regimen (~ 112%) was more efficacious than the Gem plus Cis regimen (~ 21%) in tumor growth inhibition. The Gem plus Rom + Cis regimen efficaciously reduced the development of metastatic nodules to 20% in animals. CONCLUSION: The gemcitabine plus romidepsin + cisplatin regimen was highly efficacious in controlling TNBC tumor development, recurrence, and metastasis in animals. The combination regimen should be poised for efficient translation into clinical trials for controlling the recurrence and metastasis, ultimately contributing to reducing mortality and improving TNBC patients' quality of life.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/administration & dosage , Epithelial-Mesenchymal Transition/drug effects , Reactive Oxygen Species/metabolism , Triple Negative Breast Neoplasms/drug therapy , Animals , Antineoplastic Combined Chemotherapy Protocols/pharmacology , Cell Line, Tumor , Cell Survival/drug effects , Cisplatin/administration & dosage , Deoxycytidine/administration & dosage , Deoxycytidine/analogs & derivatives , Depsipeptides/administration & dosage , Female , Humans , Mice , Mice, Nude , Neoplasm Metastasis/prevention & control , Neoplasm Recurrence, Local , Signal Transduction/drug effects , Triple Negative Breast Neoplasms/pathology , Xenograft Model Antitumor Assays , Gemcitabine
5.
Int J Mol Sci ; 22(8)2021 Apr 12.
Article in English | MEDLINE | ID: mdl-33921209

ABSTRACT

Gastrin, secreted by G-cells, and glucagon-like peptide-1 (GLP-1), secreted by L-cells, may participate in the regulation of sodium balance. We studied the effect of sodium in mice in vivo and mouse ileum and human L-cells, on GLP-1 secretion, and the role of NFAT5 and gastrin-releasing peptide receptor (GRPR) in this process. A high-sodium diet increases serum GLP-1 levels in mice. Increasing sodium concentration stimulates GLP-1 secretion from mouse ileum and L-cells. GRP enhances the high sodium-induced increase in GLP-1 secretion. High sodium increases cellular GLP-1 expression, while low and high sodium concentrations increase NFAT5 and GRPR expression. Silencing NFAT5 in L-cells abrogates the stimulatory effect of GRP on the high sodium-induced GLP-1 secretion and protein expression, and the sodium-induced increase in GRPR expression. GLP-1 and gastrin decrease the expression of Na+-K+/ATPase and increase the phosphorylation of sodium/hydrogen exchanger type 3 (NHE3) in human renal proximal tubule cells (hRPTCs). This study gives a new perspective on the mechanisms of GLP-1 secretion, especially that engendered by ingested sodium, and the ability of GLP-1, with gastrin, to decrease Na+-K+/ATPase expression and NHE3 function in hRPTCs. These results may contribute to the better utilization of current and future GLP-1-based drugs in the treatment of hypertension.


Subject(s)
Gastrins/genetics , Glucagon-Like Peptide 1/genetics , Glucagon-Like Peptide-1 Receptor/genetics , Hypertension/genetics , Transcription Factors/genetics , Animals , Gastrin-Secreting Cells/metabolism , Gene Expression Regulation/genetics , Gene Silencing , Humans , Hypertension/drug therapy , Hypertension/pathology , Kidney Tubules, Proximal/metabolism , Mice , Phosphorylation/drug effects , Sodium/metabolism , Sodium/pharmacology , Sodium-Hydrogen Exchanger 3/genetics , Sodium-Potassium-Exchanging ATPase/genetics
6.
Multidiscip Respir Med ; 16(1): 706, 2021 Jan 15.
Article in English | MEDLINE | ID: mdl-33569173

ABSTRACT

BACKGROUND: Cytomegalovirus (CMV) infection is extremely common after lung transplant and can be associated with significant morbidity and mortality. Current practice suggests the use of 900 mg daily of valganciclovir for CMV prophylaxis, but there is no literature assessing whether 450 mg daily of valganciclovir is sufficient in intermediate CMV risk lung transplant recipients. Therefore, we sought to assess the role of low-dose valganciclovir (LDV) versus high-dose valganciclovir (HDV) prophylaxis in intermediate-risk (R+) recipients. METHODS: We conducted a retrospective analysis on lung transplant recipients at the Norton Thoracic Institute in Phoenix, Arizona looking at intermediate-risk patients that received either valganciclovir 450 mg per day (LDV) or 900 mg/day (HDV). All patients were followed for 1 year post-transplant for incidence of CMV viremia. The primary outcome was the rate of CMV viremia as determined by a positive CMV polymerase chain reaction ([PCR] >2.7 log copies/mL). Secondary outcomes included rate of adverse events, acute cellular rejection, and mortality. RESULTS: The primary analysis included 103 patients (55 in the LDV group, 48 in the HDV group). In the LDV group, 9 patients (16.4%) developed CMV viremia compared to 4 (8.3%) in the HDV group (p=0.221) with no difference observed in adverse event rates between groups. CONCLUSION: There was no statistical difference between groups for the primary outcome. However, the effect size demonstrated in this analysis may be of clinical relevance and valganciclovir 450 mg daily would not be recommended in intermediate risk lung transplant recipients at this time. To confirm our results, further prospective studies enrolling larger patient populations are necessary.

7.
J Orthop Trauma ; 32(3): 116-123, 2018 03.
Article in English | MEDLINE | ID: mdl-29461445

ABSTRACT

OBJECTIVES: To determine the impact of anesthesia type on in-hospital mortality and morbidity for geriatric fragility hip fracture surgery. DESIGN: Retrospective cohort study. SETTING: Integrates health care delivery system across 38 facilities in the United States. PATIENTS/PARTICIPANTS: We identified 16,695 patients 65 years of age and older who underwent emergent hip fracture repairs between 2009 and 2014 through the Kaiser Permanente hip fracture registry and excluded pathologic or bilateral fractures. INTERVENTION: Hip fracture surgery with general or regional anesthesia. MAIN OUTCOMES MEASURES: Data on in-hospital mortality, time to death, discharge disposition, and length of stay (LOS) were analyzed among the following anesthesia types: general anesthesia (GA), regional anesthesia (RA), and intraoperative conversions from regional to general (Cv). RESULTS: Compared with RA, the hazard ratio for GA for in-hospital mortality was 1.38 and 2.23 for the Cv group; the time ratio for GA-associated time to death was 0.97 and 0.89 for the Cv group. The GA-associated time ratio for LOS before discharge was 1.01, and the hazard ratio for home discharge was 0.86, but no significance was found with the Cv group. CONCLUSIONS: RA may offer advantages over GA for fragility hip fracture surgeries when possible. In-hospital mortality, time to death, increased LOS, and discharge to an institute rather than home were all adversely influenced by GA. Furthermore, the previously understudied Cv group demonstrated adverse outcomes for in-hospital mortality and time to death. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.


Subject(s)
Anesthesia, Conduction/mortality , Anesthesia, General/mortality , Hip Fractures/surgery , Hospital Mortality , Aged , Aged, 80 and over , Female , Frail Elderly/statistics & numerical data , Hip Fractures/mortality , Humans , Length of Stay , Male , Morbidity , Osteoporotic Fractures/mortality , Osteoporotic Fractures/surgery , Registries , Retrospective Studies
8.
Perm J ; 21: 16-081, 2017.
Article in English | MEDLINE | ID: mdl-28241902

ABSTRACT

CONTEXT: Hip fracture registries offer an opportunity to identify and to monitor patients with rare conditions and outcomes, including hip fractures in pediatric patients. OBJECTIVE: To report patient demographics and surgical outcomes of pediatric patients treated surgically for hip fractures in a large integrated health care system. DESIGN: Pediatric patients (< 21 years old at the time of fracture) with hip fractures were identified between 2009 and 2012 using our health care system's hip fracture registry. MAIN OUTCOME MEASURES: Patient characteristics, type of fracture, surgical treatment, and short-term complications. RESULTS: Among 39 patients identified, 31 (79.5%) were male, and the median age was 15 years old (interquartile range: 11-17 years). Most patients were Hispanic (n = 17, 43.6%) or white (n = 14, 35.9%). There were 8 patients (20.5%) with 15 comorbidities. Delbet Type IV (intertrochanteric) fractures were the most common fracture type (n = 22, 56.4%), and fixation method was equally distributed between intramedullary, screw and sideplate, and screws (n = 12, 30.8% for each). Most surgeries were performed by medium-volume surgeons (n = 22, 56.4%) at medium- and high-volume hospitals (n = 37, 94.9%). Three 90-day readmissions (7.7%), 1 infection (2.6%), 1 malunion (2.6%), and 1 revision (2.6%) were observed in this cohort during the study period. CONCLUSION: In our series using registry data, hip fractures younger than age 21 years were more common in boys and Hispanic patients. Intertrochanteric fractures (Delbet Type IV) were the most frequently observed type in our community-based hip fracture registry. Short-term complications were infrequent.


Subject(s)
Hip Fractures/surgery , Hip/surgery , Orthopedic Procedures , Adolescent , Bone Screws , California/epidemiology , Child , Cohort Studies , Demography , Female , Hip Fractures/epidemiology , Hispanic or Latino , Hospitals , Humans , Male , Postoperative Complications , Registries , Surgeons , Treatment Outcome
9.
Sci Rep ; 6: 31782, 2016 08 22.
Article in English | MEDLINE | ID: mdl-27545104

ABSTRACT

Components of the type II CRISPR-Cas complex in bacteria have been used successfully in eukaryotic cells to facilitate rapid and accurate cell line engineering, animal model generation and functional genomic screens. Such developments are providing new opportunities for drug target identification and validation, particularly with the application of pooled genetic screening. As CRISPR-Cas is a relatively new genetic screening tool, it is important to assess its functionality in a number of different cell lines and to analyse potential improvements that might increase the sensitivity of a given screen. To examine critical aspects of screening quality, we constructed ultra-complex libraries containing sgRNA sequences targeting a collection of essential genes. We examined the performance of screening in both haploid and hypotriploid cell lines, using two alternative guide design algorithms and two tracrRNA variants in a time-resolved analysis. Our data indicate that a simple adaptation of the tracrRNA substantially improves the robustness of guide loss during a screen. This modification minimises the requirement for high numbers of sgRNAs targeting each gene, increasing hit scoring and creating a powerful new platform for successful screening.


Subject(s)
CRISPR-Cas Systems , Gene Editing/methods , Gene Targeting/methods , Genetic Engineering/methods , Genetic Testing/methods , Base Sequence , Cell Line, Tumor , HEK293 Cells , HL-60 Cells , Humans , RNA, Guide, Kinetoplastida/genetics , Reproducibility of Results
10.
Perm J ; 19(3): 29-36, 2015.
Article in English | MEDLINE | ID: mdl-26057682

ABSTRACT

Cases of hip fracture recorded from 1/2009 to 12/2011 were ascertained using the Kaiser Permanente Hip Fracture Registry. The registry collects information on patient, procedure, surgeon, facility, and surgical outcomes. The population (N = 12,562) was predominantly white, women, and older (≥ 75 years), and 32% had at least 5 comorbidities. The average length of follow-up was 1.1 years. Hemiarthroplasty was the most common procedure (33.1%). Most fractures were treated by medium-volume surgeons at high-volume facilities. The 90-day readmission rate was 22.1%, and the mortality rate was 12.3%.


Subject(s)
Hip Fractures , Outcome Assessment, Health Care/methods , Registries , Aged , Aged, 80 and over , Arthroplasty, Replacement, Hip/methods , Arthroplasty, Replacement, Hip/statistics & numerical data , Comorbidity , Female , Hip Fractures/epidemiology , Hip Fractures/surgery , Hospital Mortality , Humans , Length of Stay/statistics & numerical data , Male , Middle Aged , Postoperative Complications/epidemiology , United States/epidemiology
11.
Dis Model Mech ; 7(8): 953-61, 2014 Aug.
Article in English | MEDLINE | ID: mdl-25056698

ABSTRACT

Cyclosporin A (CsA) has direct effects on neural stem and progenitor cells (together termed neural precursor cells; NPCs) in the adult central nervous system. Administration of CsA in vitro or in vivo promotes the survival of NPCs and expands the pools of NPCs in mice. Moreover, CsA administration is effective in promoting NPC activation, tissue repair and functional recovery in a mouse model of cortical stroke. The mechanism(s) by which CsA mediates this cell survival effect remains unknown. Herein, we examined both calcineurin-dependent and calcineurin-independent pathways through which CsA might mediate NPC survival. To examine calcineurin-dependent pathways, we utilized FK506 (Tacrolimus), an immunosuppressive molecule that inhibits calcineurin, as well as drugs that inhibit cyclophilin A-mediated activation of calcineurin. To evaluate the calcineurin-independent pathway, we utilized NIM811, a non-immunosuppressive CsA analog that functions independently of calcineurin by blocking mitochondrial permeability transition pore formation. We found that only NIM811 can entirely account for the pro-survival effects of CsA on NPCs. Indeed, blocking signaling pathways downstream of calcineurin activation using nNOS mice did not inhibit CsA-mediated cell survival, which supports the proposal that the effects are calcinuerin-independent. In vivo studies revealed that NIM811 administration mimics the pro-survival effects of CsA on NPCs and promotes functional recovery in a model of cortical stroke, identical to the effects seen with CsA administration. We conclude that CsA mediates its effect on NPC survival through calcineurin-independent inhibition of mitochondrial permeability transition pore formation and suggest that this pathway has potential therapeutic benefits for developing NPC-mediated cell replacement strategies.


Subject(s)
Calcineurin/metabolism , Cyclosporine/pharmacology , Neural Stem Cells/cytology , Neural Stem Cells/metabolism , Signal Transduction/drug effects , Animals , Cell Count , Cell Survival/drug effects , Cyclosporine/administration & dosage , Male , Mice, Inbred C57BL , Neural Stem Cells/drug effects , Neural Stem Cells/enzymology , Nitric Oxide Synthase Type I/metabolism , Recovery of Function/drug effects , Spheroids, Cellular/cytology , Spheroids, Cellular/drug effects , Stroke/physiopathology , Tacrolimus/pharmacology , bcl-Associated Death Protein/metabolism
12.
J Clin Microbiol ; 50(1): 127-33, 2012 Jan.
Article in English | MEDLINE | ID: mdl-22075595

ABSTRACT

The purpose of this study was to evaluate the impact of real-time PCR reporting both on timely identification of clustered Gram-positive cocci (GPC) in blood cultures and on appropriate antibiotic treatment. This retrospective, interventional cohort study evaluated inpatients with blood cultures positive for GPC in the pre-PCR (15 January 2009 to 14 January 2010) and post-PCR (15 January 2010 to 14 January 2011) periods. Post-PCR implementation, laboratory services completed batched PCR; results other than methicillin-resistant Staphylococcus aureus (MRSA) were reported in the electronic medical record without additional interventions. The assay's sensitivity and specificity, time to identification of staphylococcal bacteremia, and clinically relevant outcomes, including time to optimal antibiotic therapy, were evaluated. Demographic information was also collected and analyzed. Sixty-eight and 58 patients with Staphylococcus aureus bacteremia from the pre- and post-PCR periods, respectively, met inclusion criteria. Similar numbers of consecutive patients with coagulase-negative staphylococci were analyzed for comparison. The time to identification was significantly reduced post-PCR implementation (mean, 13.2 h; 95% confidence interval [95% CI], 10.5 to 15.9 h; P < 0.0001). However, the time to optimal antibiotic therapy was not significantly reduced. We conclude that implementation of a PCR assay demonstrated the potential to improve appropriate antibiotic use based on clinically meaningful and statistically significant reductions in the time to microbiologic identification. However, in order to realize this potential benefit, processes must be optimized and additional interventions initiated to facilitate providers' use of the PCR result.


Subject(s)
Bacteremia/diagnosis , Bacteremia/microbiology , Molecular Diagnostic Techniques/methods , Real-Time Polymerase Chain Reaction/methods , Staphylococcal Infections/diagnosis , Staphylococcal Infections/microbiology , Staphylococcus aureus/isolation & purification , Aged , Anti-Bacterial Agents/administration & dosage , Bacteremia/drug therapy , Bacteriological Techniques/methods , Cohort Studies , Female , Humans , Male , Middle Aged , Retrospective Studies , Sensitivity and Specificity , Staphylococcal Infections/drug therapy , Staphylococcus aureus/genetics , Time Factors
13.
J Pain Symptom Manage ; 41(5): 836-47, 2011 May.
Article in English | MEDLINE | ID: mdl-21276700

ABSTRACT

CONTEXT: Although prayer potentially serves as an important practice in offering religious/spiritual support, its role in the clinical setting remains disputed. Few data exist to guide the role of patient-practitioner prayer in the setting of advanced illness. OBJECTIVES: To inform the role of prayer in the setting of life-threatening illness, this study used mixed quantitative-qualitative methods to describe the viewpoints expressed by patients with advanced cancer, oncology nurses, and oncology physicians concerning the appropriateness of clinician prayer. METHODS: This is a cross-sectional, multisite, mixed-methods study of advanced cancer patients (n=70), oncology physicians (n=206), and oncology nurses (n=115). Semistructured interviews were used to assess respondents' attitudes toward the appropriate role of prayer in the context of advanced cancer. Theme extraction was performed based on interdisciplinary input using grounded theory. RESULTS: Most advanced cancer patients (71%), nurses (83%), and physicians (65%) reported that patient-initiated patient-practitioner prayer was at least occasionally appropriate. Furthermore, clinician prayer was viewed as at least occasionally appropriate by the majority of patients (64%), nurses (76%), and physicians (59%). Of those patients who could envision themselves asking their physician or nurse for prayer (61%), 86% would find this form of prayer spiritually supportive. Most patients (80%) viewed practitioner-initiated prayer as spiritually supportive. Open-ended responses regarding the appropriateness of patient-practitioner prayer in the advanced cancer setting revealed six themes shaping respondents' viewpoints: necessary conditions for prayer, potential benefits of prayer, critical attitudes toward prayer, positive attitudes toward prayer, potential negative consequences of prayer, and prayer alternatives. CONCLUSION: Most patients and practitioners view patient-practitioner prayer as at least occasionally appropriate in the advanced cancer setting, and most patients view prayer as spiritually supportive. However, the appropriateness of patient-practitioner prayer is case specific, requiring consideration of multiple factors.


Subject(s)
Attitude of Health Personnel , Faith Healing/statistics & numerical data , Neoplasms/epidemiology , Neoplasms/nursing , Palliative Care/statistics & numerical data , Patient Satisfaction/statistics & numerical data , Terminal Care/statistics & numerical data , Adult , Boston/epidemiology , Female , Humans , Male , Middle Aged , Nurse-Patient Relations , Physician-Patient Relations , Prevalence
14.
PLoS One ; 5(10): e13322, 2010 Oct 12.
Article in English | MEDLINE | ID: mdl-20967285

ABSTRACT

The Raf/ERK (Extracellular Signal Regulated Kinase) signal transduction pathway controls numerous cellular processes, including growth, differentiation, cellular transformation and senescence. ERK activation is thought to involve complex spatial and temporal regulation, to achieve a high degree of specificity, though precisely how this is achieved remains to be confirmed. We report here that prolonged activation of a conditional form of c-Raf-1 (BXB-ER) leads to profound changes in the level and distribution of a heterochromatic histone mark. In mouse fibroblasts, the heterochromatic trimethylation of lysine 9 in histone H3 (H3K9Me3) is normally confined to pericentromeric regions. However, following ERK activation a genome-wide redistribution of H3K9Me3 correlates with loss of the histone modification from chromocentres and the appearance of numerous punctuate sites throughout the interphase nucleus. These epigenetic changes during interphase correlate with altered chromosome structure during mitosis, where robust H3K9Me3 signals appear within telomeric heterochromatin. This pattern of heterochromatinization is distinct from previously described oncogene induced senescence associated heterochromatin foci (SAHF), which are excluded from telomeres. The H3K9Me3 histone mark is known to bind the major heterochromatin protein HP1 and we show that the alterations in the distribution of this histone epistate correlate with redistribution of HP1ß throughout the nucleus. Interestingly while ERK activation is fully reversible, the observed chromatin changes induced by epigenetic modifications are not reversible once established. We describe for the first time a link from prolonged ERK activation to stable changes in genome organization through redistribution of heterochromatic domains involving the telomeres. These epigenetic changes provide a possible mechanism through which prolonged activation of Raf/ERK can lead to growth arrest or the induction of differentiation, senescence and cancer.


Subject(s)
Extracellular Signal-Regulated MAP Kinases/metabolism , Heterochromatin/genetics , Signal Transduction , raf Kinases/metabolism , 3T3 Cells , Animals , Enzyme Activation , Mice
15.
J Neurosci ; 30(8): 2888-96, 2010 Feb 24.
Article in English | MEDLINE | ID: mdl-20181586

ABSTRACT

Multipotent, self-renewing neural stem cells and their progeny [collectively referred to as neural precursor cells (NPCs)] represent a population of cells with great promise for CNS repair. To effectively harness their potential for therapeutic applications, the factors that regulate NPC behavior and/or fate must be well understood. The ability of immunomodulatory molecules to affect NPC behavior is of interest because of recent work elucidating the complex interactions between the immune system and nervous system. Herein, we examined the effects of cyclosporin A, a commonly used immunosuppressive molecule, on NPC proliferation kinetics, survival, and fate using in vitro assays at the population level and at the single-cell level. The use of pure populations of NPCs revealed a direct effect of cyclosporin A on cell survival, resulting in increased numbers and larger colonies, with no effect on proliferation kinetics. Cyclosporin A did not alter the differentiation profile of NPC colonies, indicating that it did not promote selective survival of a particular neural lineage. Additionally, we observed decreased cell-cell adhesions in developing cyclosporin A-treated NPC colonies. Consistent with the in vitro observations, in vivo administration of cyclosporin A to adult animals increased the numbers of NPCs within the neurogenic niche lining the lateral ventricles. Together, our findings establish that cyclosporin A has direct effects on NPCs both in vitro and in vivo, making it a promising candidate molecule for developing clinically relevant strategies to stimulate NPCs for brain repair.


Subject(s)
Cyclosporine/pharmacology , Nerve Regeneration/drug effects , Neurogenesis/drug effects , Neurons/drug effects , Stem Cells/drug effects , Telencephalon/drug effects , Animals , Brain Diseases/therapy , Cell Adhesion/drug effects , Cell Adhesion/physiology , Cell Differentiation/drug effects , Cell Differentiation/physiology , Cell Lineage/drug effects , Cell Lineage/physiology , Cell Movement/drug effects , Cell Movement/physiology , Cell Proliferation/drug effects , Cell Survival/drug effects , Cell Survival/physiology , Immunosuppressive Agents/pharmacology , Lateral Ventricles/cytology , Male , Mice , Nerve Regeneration/physiology , Neurogenesis/physiology , Neurons/physiology , Stem Cells/physiology , Telencephalon/cytology , Telencephalon/physiology
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