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1.
Br J Anaesth ; 131(6): 981-988, 2023 12.
Article in English | MEDLINE | ID: mdl-37838604

ABSTRACT

BACKGROUND: Reducing the need for blood transfusion among patients undergoing cardiac surgery FLA reduce postoperative complications and mortality. Our study aimed to assess the effects of administering preoperative i.v. ferric carboxymaltose on postoperative red cell transfusion requirements in patients without anaemia undergoing on-pump cardiac surgery. METHODS: This double-blind, randomised, placebo-controlled trial was conducted between October 2016 and November 2019, with a follow-up period of up to 6 weeks after surgery. Patients without anaemia who underwent on-pump cardiac surgery were included as participants and administered i.v. iron in the form of ferric carboxymaltose or placebo once, 24-72 h before surgery. The primary outcome was the number of red cell units transfused during the first four postoperative days, and the secondary outcome measures were blood haemoglobin concentrations at 4 days and 6 weeks after surgery. RESULTS: The 200 patients included were randomly assigned to the ferric carboxymaltose (n=102) and placebo (n=98) groups. By postoperative Day 4, a significantly lower mean number of red cell units were transfused in the ferric carboxymaltose than in the placebo group, 0.3 (0.8) vs 1.6 (4.4), respectively; P=0.007. The mean haemoglobin concentrations on postoperative Day 4 were 9.7 (1) g dl-1 and 9.3 (1) g dl-1, respectively (P=0.03). Corresponding values at 6 weeks after surgery were 12.6 (1.4) g dl-1 and 11.8 (1.5) g dl-1, respectively (P=0.012). CONCLUSIONS: In patients without anaemia undergoing on-pump cardiac surgery, treatment with a single dose of 1000 mg ferric carboxymaltose i.v. 1-3 days before surgery significantly reduced the need for red cell transfusions and increased the postoperative haemoglobin concentration. CLINICAL TRIAL REGISTRATION: NCT02939794.


Subject(s)
Anemia , Cardiac Surgical Procedures , Humans , Administration, Intravenous , Anemia/drug therapy , Erythrocyte Transfusion , Ferric Compounds/therapeutic use , Hemoglobins/analysis , Iron/therapeutic use , Maltose/therapeutic use , Double-Blind Method
2.
IEEE Trans Biomed Eng ; 68(7): 2110-2116, 2021 07.
Article in English | MEDLINE | ID: mdl-32960760

ABSTRACT

BACKGROUND: Peri-device leak (PDL) following left atrial appendage occlusion (LAAO) may lead to an increased risk of thrombosis. However, current modalities for PDL detection, such as trans-esophageal echo (TEE) and cardiac CT do not provide quantitative measures of PDL. OBJECTIVE: to use dielectric imaging (DI) to measure PDL from a Watchman (WM) LAAO device. METHODS: A conductivity contrast agent is injected into the left atrium (LA) through the WM delivery system, while making DI measurements. Recordings are analyzed with a two-compartment model and the flow from the left atrial appendage (LAA) characterized by a "% clearance / beat" (CPB) parameter. With ethics approval, four dogs (26 ± 1.8  kg) were anesthetized and ventilated. Body-surface electrodes were placed and impedance data continuously acquired. WM devices (0-35% oversized) were introduced and placed into the LAA. During the study, the WM was either fully or partial deployed. At each deployment level, 10 mL of conductivity contrast was injected through the WM delivery sheath. At twenty-two deployment conditions, Doppler-flow TEE measurements were made, and compared to the DI-based value. RESULTS: In all cases, CPB values correctly predicted the TEE-based assessment of PDL (100% sensitivity/specificity). The TEE leak size also corresponded to CPB values with a correlation of r = 0.914 (p 0.001). CONCLUSION: Using DI signals, the leak flow from the WM LAAO can be measured and yields comparative results to TEE for detection of PDL. The DI method requires no other imaging modality or ionizing radiation and iodine contrast agent injection.


Subject(s)
Atrial Appendage , Atrial Fibrillation , Animals , Atrial Appendage/diagnostic imaging , Atrial Fibrillation/diagnostic imaging , Cardiac Catheterization , Dogs , Echocardiography, Transesophageal , Treatment Outcome
3.
Rambam Maimonides Med J ; 10(2)2019 Apr 18.
Article in English | MEDLINE | ID: mdl-30817267

ABSTRACT

OBJECTIVE: Extracorporeal membrane oxygenation is used to bypass the cardiopulmonary system in a severe heart or/and lung failure, mainly in intractable conditions where all other therapy options fail or are unfeasible. Extracorporeal membrane oxygenation (ECMO) is a well-established therapeutic option in such circumstances for neonatal, pediatric, and adult patients. Managing a patient with ECMO requires dedicated and specific management. The importance and necessity of this essential technology in life-threatening cardio-respiratory rescue prompted Rambam Health Care Campus to implement it and make it available as a service to the population in northern Israel. This article includes a brief review of extracorporeal life support and a report of our single-center experience since the establishment of the service. METHODS: The ECMO unit was established in 2014 under the responsibility of the Cardiac Surgery Department. The ECMO service was initiated by a well-planned program with consideration of all aspects including economics, education and training, the specialist team and equipment needed, strategies for medication, and ethical challenges. RESULTS: Between February 2014 and May 2018, 65 patients were treated with ECMO; 43 patients received veno-arterial ECMO for cardiac support (66%), while 22 received veno-venous ECMO for respiratory support (34%). The in-hospital mortality was 56%. CONCLUSIONS: Extracorporeal membrane oxygenation is an effective therapy that is constantly growing in use and provides a therapy that can replace previous options. To establish such a service requires a planned program and concerted effort. Our single-center experience presented a good learning curve and showed the feasibility as well as the efficacy of the ECMO procedure in life-threatening conditions.

4.
Asian Cardiovasc Thorac Ann ; 25(6): 425-431, 2017 Jul.
Article in English | MEDLINE | ID: mdl-28648116

ABSTRACT

Background Neurologic complications and neurocognitive impairment due to cerebral emboli are common following heart surgery. This study aimed to compare the number of emboli detected in the middle cerebral artery in open aortic valve replacement, apical and femoral transcatheter aortic valve replacement, and also to test for an association between the number of emboli captured in each procedure and changes in the patient's cognitive state. Methods Forty-four patients were enrolled in the study, 36 of whom were included in the final analyses: 14 underwent open aortic valve replacement, 2 had femoral transcatheter aortic valve replacement, and 10 had apical transcatheter aortic valve replacement. The number of emboli was detected by middle cerebral artery intraoperative transcranial Doppler ultrasound. The day before the elective surgery and 6-12 weeks later, all patients underwent neurocognitive evaluations by the Mini-Mental State Examination; the difference was tested for an association with the number of emboli. Results Open aortic valve replacement resulted in a significantly greater number of emboli (8555, range 2999-12489) than apical (1962, range 521-3850) or femoral (1220, range 948-1946) transcatheter approaches ( p = 0.003). Both transcatheter approaches yielded a comparable amount of emboli ( p = 0.798). No significant association was observed between the change in Mini-Mental State Examination score and the mean number of emboli ( r = 0.026; p = 0.907). Conclusions Compared to transcatheter aortic valve replacement, more cerebral emboli are detected during surgical aortic valve replacement; however, this does not appear to adversely affect a patient's cognitive state.


Subject(s)
Aortic Valve Stenosis/surgery , Aortic Valve/surgery , Cognition Disorders/etiology , Cognition , Heart Valve Prosthesis Implantation/adverse effects , Infarction, Middle Cerebral Artery/etiology , Intracranial Embolism/etiology , Transcatheter Aortic Valve Replacement/adverse effects , Aged , Aged, 80 and over , Cognition Disorders/diagnosis , Cognition Disorders/psychology , Female , Humans , Infarction, Middle Cerebral Artery/diagnostic imaging , Intracranial Embolism/diagnostic imaging , Male , Mental Status and Dementia Tests , Psychiatric Status Rating Scales , Risk Factors , Treatment Outcome , Ultrasonography, Doppler, Transcranial
5.
J Thorac Cardiovasc Surg ; 151(5): 1302-8.e1, 2016 May.
Article in English | MEDLINE | ID: mdl-26832208

ABSTRACT

OBJECTIVE: To verify the rate of thromboembolic and hemorrhagic complications during the first 6 months after mitral valve repair and to assess whether the type of antithrombotic therapy influenced clinical outcome. METHODS: Retrospective data were retrieved from 19 centers. Inclusion criteria were isolated mitral valve repair with ring implantation. Exclusion criteria were ongoing or past atrial fibrillation and any combined intraoperative surgical procedures. The study cohort consisted of 1882 patients (aged 58 ± 15 years; 36% women), and included 1517 treated with an oral anticoagulant (VKA group) and 365 with antiplatelet drugs (APLT group). Primary efficacy outcome was the incidence of arterial thromboembolic events within 6 months and primary safety outcome was the incidence of major bleeding within 6 months. Propensity matching was performed to obtain 2 comparable cohorts (858 vs 286). RESULTS: No differences were detected for arterial embolic complications in matched cohort (1.6% VKA vs 2.1% APLT; P = .50). Conversely, patients in the APLT group showed lower incidence of major bleeding complications (3.9% vs 0.7%; P = .01). Six-month mortality rate was significantly higher in the VKA group (2.7% vs 0.3%; P = .02). Multivariable analysis in the matched cohort found VKA as independent predictor of major bleeding complications and mortality at 6 months. CONCLUSIONS: Vitamin K antagonist therapy was not superior to antiplatelet therapy to prevent thromboembolic complications after mitral valve repair. Our data suggest that oral anticoagulation may carry a higher bleeding risk compared with antiplatelet therapy, although these results should be confirmed in an adequately powered randomized controlled trial.


Subject(s)
Anticoagulants/administration & dosage , Heart Valve Prosthesis Implantation/adverse effects , Hemorrhage/prevention & control , Mitral Valve Insufficiency/surgery , Platelet Aggregation Inhibitors/administration & dosage , Thromboembolism/prevention & control , Administration, Oral , Adult , Age Factors , Aged , Anticoagulants/adverse effects , Cohort Studies , Databases, Factual , Female , Follow-Up Studies , Heart Valve Prosthesis Implantation/methods , Hemorrhage/chemically induced , Humans , Injections, Subcutaneous , Male , Middle Aged , Mitral Valve Insufficiency/diagnostic imaging , Multivariate Analysis , Platelet Aggregation Inhibitors/adverse effects , Postoperative Complications/drug therapy , Postoperative Complications/prevention & control , Predictive Value of Tests , ROC Curve , Retrospective Studies , Risk Assessment , Sex Factors , Statistics, Nonparametric , Survival Rate , Thromboembolism/drug therapy , Treatment Outcome , Ultrasonography , Vitamin K/administration & dosage , Vitamin K/antagonists & inhibitors
6.
Breast Cancer Res ; 17: 78, 2015 Jun 04.
Article in English | MEDLINE | ID: mdl-26040280

ABSTRACT

INTRODUCTION: Breast tumors are comprised of distinct cancer cell populations which differ in their tumorigenic and metastatic capacity. Characterization of cell surface markers enables investigators to distinguish between cancer stem cells and their counterparts. CD24 is a well-known cell surface marker for mammary epithelial cells isolation, recently it was suggested as a potential prognostic marker in a wide variety of malignancies. Here, we demonstrate that CD24(+) cells create intra-tumor heterogeneity, and display highly metastatic properties. METHODS: The mammary carcinoma Mvt1 cells were sorted into CD24(-) and CD24(+) cells. Both subsets were morphologically and phenotypically characterized, and tumorigenic capacity was assessed via orthotopic inoculation of each subset into the mammary fat pad of wild-type and MKR mice. The metastatic capacity of each subset was determined with the tail vein metastasis assay. The role of CD24 in tumorigenesis was further examined with shRNA technology. GFP-labeled cells were monitored in vivo for differentiation. The genetic profile of each subset was analyzed using RNA sequencing. RESULTS: CD24(+) cells displayed a more spindle-like cytoplasm. The cells formed mammospheres in high efficiency and CD24(+) tumors displayed rapid growth in both WT and MKR mice, and were more metastatic than CD24- cells. Interestingly, CD24-KD in CD24+ cells had no effect both in vitro and in vivo on the various parameters studied. Moreover, CD24(+) cells gave rise in vivo to the CD24(-) that comprised the bulk of the tumor. RNA-seq analysis revealed enrichment of genes and pathways of the extracellular matrix in the CD24(+) cells. CONCLUSION: CD24(+) cells account for heterogeneity in mammary tumors. CD24 expression at early stages of the cancer process is an indication of a highly invasive tumor. However, CD24 is not a suitable therapeutic target; instead we suggest here new potential targets accounting for early differentiated cancer cells tumorigenic capacity.


Subject(s)
Breast Neoplasms/metabolism , Breast Neoplasms/pathology , CD24 Antigen/metabolism , Animals , Biomarkers , Breast Neoplasms/genetics , CD24 Antigen/genetics , Cell Line, Tumor , Cell Transformation, Neoplastic/metabolism , Disease Models, Animal , Extracellular Matrix/genetics , Extracellular Matrix/metabolism , Female , Gene Expression Profiling , Gene Expression Regulation, Neoplastic , Gene Knockout Techniques , Immunophenotyping , Mice , Neoplasm Metastasis , Neoplastic Stem Cells/metabolism , Phenotype , Tumor Burden
7.
Endocr Relat Cancer ; 22(2): 145-57, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25694511

ABSTRACT

Accumulating evidence from clinical trials indicates that specific targeting of the IGF1 receptor (IGF1R) is not efficient as an anti-breast cancer treatment. One possible reason is that the mitogenic signals from the insulin receptor (IR) can be processed independently or as compensation to inhibition of the IGF1R. In this study, we highlight the role of the IR in mediating breast tumor progression in both WT mice and a hyperinsulinemic MKR mouse model by induction of Ir (Insr) or Igf1r knockdown (KD) in the mammary carcinoma Mvt-1 cell line. By using the specific IR antagonist-S961, we demonstrated that Igf1r-KD induces elevated responses by the IR to IGF1. On the other hand, Ir-KD cells generated significantly smaller tumors in the mammary fat pads of both WT and MKR mice, as opposed to control cells, whereas the Igf1r-KD cells did not. The tumorigenic effects of insulin on the Mvt-1 cells were also demonstrated using microarray analysis, which indicates alteration of genes and signaling pathways involved in proliferation, the cell cycle, and apoptosis following insulin stimulation. In addition, the correlation between IR and the potential prognostic marker for aggressive breast cancer, CD24, was examined in the Ir-KD cells. Fluorescence-activated cell sorting (FACS) analysis revealed more than 60% reduction in CD24 expression in the Ir-KD cells when compared with the control cells. Our results also indicate that CD24-expressing cells can restore, at least in part, the tumorigenic capacity of Ir-KD cells. Taken together, our results highlight the mitogenic role of the IR in mammary tumor progression with a direct link to CD24 expression.


Subject(s)
Mammary Neoplasms, Animal/metabolism , Receptor, Insulin/metabolism , Animals , CD24 Antigen/metabolism , Cell Line, Tumor , Female , Gene Expression Regulation, Neoplastic , Insulin/pharmacology , Mammary Neoplasms, Animal/pathology , Mice , Mice, Transgenic , Mitogen-Activated Protein Kinases/metabolism , Oligonucleotide Array Sequence Analysis , Phosphatidylinositol 3-Kinases/metabolism , Proto-Oncogene Proteins c-akt/metabolism , Receptor, IGF Type 1/metabolism , Signal Transduction , Tumor Burden
8.
Endocrinology ; 154(5): 1701-10, 2013 May.
Article in English | MEDLINE | ID: mdl-23515289

ABSTRACT

Epidemiological and experimental studies have identified hyperinsulinemia as an important risk factor for breast cancer induction and for the poor prognosis in breast cancer patients with obesity and type 2 diabetes. Recently it was demonstrated that both the insulin receptor (IR) and the IGF-IR mediate hyperinsulinemia's mitogenic effect in several breast cancer models. Although IGF-IR has been intensively investigated, and anti-IGF-IR therapies are now in advanced clinical trials, the role of the IR in mediating hyperinsulinemia's mitogenic effect remains to be clarified. Here we aimed to explore the potential of IR inhibition compared to dual IR/IGF-IR blockade on breast tumor growth. To initiate breast tumors, we inoculated the mammary carcinoma Mvt-1 cell line into the inguinal mammary fat pad of the hyperinsulinemic MKR female mice, and to study the role of IR, we treated the mice bearing tumors with the recently reported high-affinity IR antagonist-S961, in addition to the well-documented IGF-IR inhibitor picropodophyllin (PPP). Although reducing IR activation, with resultant severe hyperglycemia and hyperinsulinemia, S961-treated mice had significantly larger tumors compared to the vehicle-treated group. This effect maybe secondary to the severe hyperinsulinemia mediated via the IGF-1 receptor. In contrast, PPP by partially inhibiting both IR and IGF-IR activity reduced tumor growth rate with only mild metabolic consequences. We conclude that targeting (even partially) both IR and IGF-IRs impairs hyperinsulinemia's effects in breast tumor development while simultaneously sparing the metabolic abnormalities observed when targeting IR alone with virtual complete inhibition.


Subject(s)
Breast Neoplasms/therapy , Carcinoma/therapy , Cell Proliferation/drug effects , Hyperinsulinism/drug therapy , Insulin/adverse effects , Molecular Targeted Therapy/methods , Animals , Breast Neoplasms/complications , Breast Neoplasms/genetics , Breast Neoplasms/pathology , Carcinoma/complications , Carcinoma/genetics , Carcinoma/pathology , Cell Line, Tumor , Disease Models, Animal , Female , Growth Substances/adverse effects , Hyperinsulinism/complications , Hyperinsulinism/genetics , Hyperinsulinism/pathology , Mammary Neoplasms, Experimental/complications , Mammary Neoplasms, Experimental/genetics , Mammary Neoplasms, Experimental/pathology , Mammary Neoplasms, Experimental/therapy , Mice , Mice, Transgenic , Peptides/therapeutic use , Podophyllotoxin/analogs & derivatives , Podophyllotoxin/therapeutic use , Receptor, IGF Type 1/antagonists & inhibitors , Receptor, IGF Type 1/genetics , Therapies, Investigational/methods
9.
Int J Biol Sci ; 7(7): 1003-15, 2011.
Article in English | MEDLINE | ID: mdl-21912508

ABSTRACT

Since the incidence of the metabolic syndrome is on the rise in the western world, its coherence to cancer is becoming more apparent. In this review we discuss the different potential factors involved in the increase of cancer in the metabolic syndrome including obesity, dyslipidemia and Type 2 Diabetes Mellitus (T2DM) as well as inflammation and hypoxia. We especially focus on the insulin and IGF systems with their intracellular signaling cascades mediated by different receptor subtypes, and suggest that they may play major roles in this process. Understanding the mechanisms involved will be helpful in developing potential therapeutics.


Subject(s)
Metabolic Syndrome/complications , Neoplasms/complications , Dyslipidemias/complications , Dyslipidemias/metabolism , Incidence , Insulin/metabolism , Insulin-Like Growth Factor Binding Proteins/metabolism , Insulin-Like Growth Factor Binding Proteins/physiology , Insulin-Like Growth Factor I/metabolism , Insulin-Like Growth Factor I/physiology , Metabolic Syndrome/metabolism , Models, Biological , Neoplasms/metabolism , Obesity/complications , Obesity/metabolism , Receptor, Insulin/metabolism , Receptor, Insulin/physiology , Risk Factors , Signal Transduction , TOR Serine-Threonine Kinases/metabolism , TOR Serine-Threonine Kinases/physiology
10.
Rambam Maimonides Med J ; 2(2): e0043, 2011 Apr.
Article in English | MEDLINE | ID: mdl-23908801

ABSTRACT

Patients with type 2 diabetes (T2D) are at increased risk of developing cancer. This evidence arises from numerous epidemiologic studies that relate a positive association between T2D and cancer. In-vitro and several in-vivo experiments have attempted to discern the potential mechanistic factors involved in this relationship. Candidates include hyperinsulinemia, insulin-like growth factor-1 (IGF-1), and insulin-like growth factor-2 (IGF-2) signaling. These studies demonstrated that increased insulin, IGF-1, and IGF-2 signaling through the insulin receptor and IGF-1 receptor can induce cancer development and progression.

11.
Mol Cancer ; 9: 54, 2010 Mar 09.
Article in English | MEDLINE | ID: mdl-20214788

ABSTRACT

BACKGROUND: The AP-1 transcription factor plays a major role in cell proliferation, apoptosis, differentiation and developmental processes. AP-1 proteins are primarily considered to be oncogenic. Gene disruption studies placed c-Jun as an oncogene at the early stage of a mouse model of hepatocellular carcinoma. Mice lacking c-Jun display reduced number and size of hepatic tumors attributed to elevated p53 expression and increased apoptosis. This suggests that c-Jun inhibition may serve as a therapeutic target for liver cancer. The c-Jun dimerization protein 2, JDP2 is an AP-1 repressor protein that potently inhibits AP-1 transcription. On the other hand, the JDP2 locus was found at a recurring viral integration site in T-cell lymphoma. We sought to examine the potential of JDP2 to inhibit c-Jun/AP-1 oncogenic activity in mice. Towards this end, we generated a tetracycline inducible transgenic mouse expressing JDP2 specifically in the liver. We used diethylnitrosamine (DEN) injection to initiate liver cancer in mice and assessed the extent of liver cancer in JDP2-transgenic and wild type control mice by biochemical and molecular biology techniques. RESULTS: JDP2-transgenic mice display normal liver function. JDP2-transgenic mice displayed potentiation of liver cancer, higher mortality and increased number and size of tumors. The expression of JDP2 at the promotion stage was found to be the most critical for enhancing liver cancer severity. CONCLUSIONS: This study suggests that JDP2 expression may play a critical role in liver cancer development by potentiating the compensatory proliferative response and increased inflammation in the DEN liver cancer model.


Subject(s)
Carcinoma, Hepatocellular/pathology , Liver Neoplasms/pathology , Repressor Proteins/metabolism , Transcription Factor AP-1/metabolism , Animals , Carcinoma, Hepatocellular/genetics , Diethylnitrosamine , Gene Expression Profiling , Gene Expression Regulation, Neoplastic , Liver/metabolism , Liver/pathology , Liver Neoplasms/genetics , Mice , Mice, Transgenic , Organ Specificity , Repressor Proteins/genetics , Survival Analysis , Transcription Factor AP-1/genetics
12.
Nucleic Acids Res ; 36(11): 3608-19, 2008 Jun.
Article in English | MEDLINE | ID: mdl-18463134

ABSTRACT

The c-Jun dimerization protein 2, JDP2, is a member of the activating protein 1 (AP-1) family of transcription factors. Overexpression of JDP2 has been shown to result in repression of AP-1-dependent transcription and inhibition of cellular transformation. Other studies suggested that JDP2 may function as an oncogene. Here we describe the identification of CHOP10, a member of the CCAAT enhancer binding proteins, as a protein associating with JDP2. In contrast to the inhibition of transcription by JDP2, JDP2-CHOP complex strongly enhances transcription from promoters containing TPA response elements (TRE), but not from those containing cyclic AMP response elements (CRE). The association between JDP2 and CHOP10 involves the leucine zipper motifs of both proteins, whereas, the basic domain of CHOP10 contributes to the association of the JDP2-CHOP10 complex with the DNA. DNA binding of JDP2-CHOP complex is observed both in vitro and in vivo. Finally, overexpression of JDP2 results in increased cell viability following ER stress and counteracts CHOP10 pro-apoptotic activity. JDP2 expression may determine the threshold for cell sensitivity to ER stress. This is the first report describing TRE-dependent activation of transcription by JDP2 and thus may provide an explanation for the as yet unexplored oncogenic properties of JDP2.


Subject(s)
Repressor Proteins/metabolism , Response Elements , Transcription Factor CHOP/metabolism , Transcriptional Activation , Animals , DNA/metabolism , Endoplasmic Reticulum/metabolism , HeLa Cells , Humans , Immunoprecipitation , Mice , NIH 3T3 Cells , Protein Structure, Tertiary , Proto-Oncogene Proteins p21(ras)/metabolism , Rats , Recombinant Fusion Proteins/metabolism , Repressor Proteins/genetics , Tetradecanoylphorbol Acetate/pharmacology , Transcription Factor CHOP/chemistry , Transcription Factor CHOP/genetics , Two-Hybrid System Techniques
13.
Mol Cell Biol ; 26(20): 7791-805, 2006 Oct.
Article in English | MEDLINE | ID: mdl-16923969

ABSTRACT

Endocytosis is important for a variety of functions in eukaryotic cells, including the regulation of signaling cascades via transmembrane receptors. The internalization of bone morphogenetic protein (BMP) receptor type I (BRI) and type II (BRII) and its relation to signaling were largely unexplored. Here, we demonstrate that both receptor types undergo constitutive endocytosis via clathrin-coated pits (CCPs) but that only BRII undergoes also caveola-like internalization. Using several complementary approaches, we could show that (i) BMP-2-mediated Smad1/5 phosphorylation occurs at the plasma membrane in nonraft regions, (ii) continuation of Smad signaling resulting in a transcriptional response requires endocytosis via the clathrin-mediated route, and (iii) BMP signaling leading to alkaline phosphatase induction initiates from receptors that fractionate into cholesterol-enriched, detergent-resistant membranes. Furthermore, we show that BRII interacts with Eps15R, a constitutive component of CCPs, and with caveolin-1, the marker protein of caveolae. Taken together, the localization of BMP receptors in distinct membrane domains is prerequisite to their taking different endocytosis routes with specific impacts on Smad-dependent and Smad-independent signaling cascades.


Subject(s)
Bone Morphogenetic Protein Receptors, Type II/metabolism , Bone Morphogenetic Protein Receptors, Type I/metabolism , Bone Morphogenetic Proteins/metabolism , Endocytosis , Signal Transduction , Animals , Bone Morphogenetic Protein Receptors, Type II/genetics , Calcium-Binding Proteins/genetics , Calcium-Binding Proteins/metabolism , Caveolae/metabolism , Caveolin 1/metabolism , Cell Line , Chlorocebus aethiops , Cholesterol/metabolism , Genetic Variation/genetics , Humans , Mice , Microscopy, Electron , Mutation/genetics , Phosphoproteins/genetics , Phosphoproteins/metabolism , Phosphorylation , Protein Binding , RNA Splicing , Smad Proteins/metabolism
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