RÉSUMÉ
BACKGROUND: The iStent (Glaukos Corporation; Laguna Hills, CA, USA) is one of the minimally invasive glaucoma devices. It can be inserted at the time of phacoemulsification or as a stand-alone procedure to lower the intraocular pressure (IOP). OBJECTIVE: Our aim was to conduct a systematic review and meta-analysis comparing the effect of iStent insertion at the time of phacoemulsification with phacoemulsification alone in patients with ocular hypertension or open-angle glaucoma. METHODS: We searched EMBASE, MEDLINE (OVID and PubMed), CINAHL, and Cochrane Library for articles published between 2008 and June 2022 (PRISMA 2020 for the checklist). Studies comparing the IOP-lowering effect of iStent with phacoemulsification versus phacoemulsification alone were included. The endpoints were IOP reduction (IOPR) and the mean reduction in the number of glaucoma drops. A quality-effects model was used to compare both surgical groups. RESULTS: Ten studies were included, reporting on 1,453 eyes. Eight hundred fifty three eyes had the combined iStent and phacoemulsification, and 600 eyes underwent phacoemulsification alone. IOPR was higher in the combined surgery at of 4.7 ± 2 mm Hg compared to 2.8 ± 1.9 mm Hg in phacoemulsification alone. A greater decrease in postoperative eye drops was noted in the combined group having a decrease of 1.2 ± 0.3 eye drops versus of 0.6 ± 0.6 drops in isolated phacoemulsification. The quality effect model showed an IOPR weighted mean difference (WMD) of 1.22 mm Hg (confidence interval [CI]: [-0.43, 2.87]; Q = 315.64; p < 0.01; I2 = 97%) and decreased eye drops WMD 0.42 drops (CI: [0.22, 0.62]; Q = 42.6; p < 0.01; I2 = 84%) between both surgical groups. Subgroup analysis shows that the new generation iStent may be more effective in reducing IOP. CONCLUSION: iStent has a synergetic effect with phacoemulsification. The reduction of IOP and glaucoma eye drops was higher when iStent is combined with phacoemulsification compared with isolated phacoemulsification.
Sujet(s)
Implants de drainage du glaucome , Glaucome à angle ouvert , Glaucome , Phacoémulsification , Humains , Phacoémulsification/méthodes , Glaucome à angle ouvert/complications , Glaucome à angle ouvert/chirurgie , Glaucome/chirurgie , Pression intraoculaire , Réseau trabéculaire de la sclère/chirurgie , Solutions ophtalmiquesRÉSUMÉ
Chemotherapy resistance is an obstacle to cancer therapy and is considered a major cause of recurrence. Thus, understanding the mechanisms of chemoresistance is critical to improving the prognosis of patients. Here, we have established a stepwise gemcitabine-resistant T24 bladder cancer cell line to understand the molecular mechanisms of chemoresistance within cancer cells. The characteristics of the stepwise chemoresistance cell line were divided into 4 phases (parental, early, intermediate, and late phases). These four phase cells showed increasingly aggressive phenotypes in vitro and in vivo experiments with increasing phases and revealed the molecular properties of the biological process from parent cells to phased gemcitabine-resistant cell line (GRC). Taken together, through the analysis of gene expression profile data, we have characterized gene set of each phase indicating the response to anticancer drug treatment. Specifically, we identified a multigene signature (23 genes including GATA3, APOBEC3G, NT5E, MYC, STC1, FOXD1, SMAD9) and developed a chemoresistance score consisting of that could predict eventual responsiveness to gemcitabine treatment. Our data will contribute to predicting chemoresistance and improving the prognosis of bladder cancer patients.
RÉSUMÉ
Sonodynamic therapy has shown promise as an effective alternative to conventional photodynamic therapy owing to its ability to treat deep-seated tumors. However, the development of stimuli-responsive sonosensitizers with high biocompatibility faces a significant challenge. Methods: In this study, we developed dual stimuli-responsive sonosensitizers with desirable biosafety using extracellular vesicles (EVs), a class of naturally occurring nanoparticles. Indocyanine green (ICG), which functions as both a sonosensitizer and photoacoustic (PA) imaging agent, was loaded into EVs, together with paclitaxel (PTX) and sodium bicarbonate (SBC), to achieve pH-responsive PA imaging-guided chemo-sonodynamic combination therapy. Results: The EVs significantly improved the cellular uptake of ICG, thus triggering enhanced sonodynamic effects in breast cancer cells. SBC-, ICG-, and PTX-loaded EV [SBC-EV(ICG/PTX)] efficiently released the PTX in response to acidic pH in the endo/lysosomes because CO2 bubbles generated from the SBC caused the EV membranes to burst. The drug release was further facilitated by ultrasound (US) treatment, demonstrating dual pH/US-responsive drug release. The ICG- and PTX-loaded EVs exhibited efficient anticancer activity against breast tumor cells owing to the combination of chemo-sonodynamic therapy. High-resolution PA imaging visualized the preferential tumor accumulation of SBC-EV(ICG/PTX) in tumor-bearing mice. Notably, a single intravenous injection of SBC-EV(ICG/PTX) with US irradiation significantly suppressed tumor growth in mice without systemic toxicity. Conclusions: Our findings demonstrate that dual stimuli-responsive SBC-EV(ICG/PTX) are promising sonotheranostic nanoplatforms for safe and efficient chemo-sonodynamic combination cancer therapy and photoacoustic imaging.
Sujet(s)
Vésicules extracellulaires , Nanoparticules , Tumeurs , Techniques photoacoustiques , Animaux , Lignée cellulaire tumorale , Libération de médicament , Humains , Vert indocyanine , Souris , Paclitaxel/pharmacologieRÉSUMÉ
PURPOSE: Cenegermin, (OXERVATE) a recently Food and Drug Administration-approved topical formulation of recombinant human nerve growth factor, has been used for the treatment of neurotrophic keratopathy (NK). Corneal deposits have been previously reported as a potential adverse effect; however, the clinical characteristics, visual significance, and treatment options have not been fully described. The purpose of this article is to better characterize corneal deposits occurring during treatment with cenegermin for neurotrophic keratopathy. METHODS: This was a retrospective, multicenter consecutive case series. RESULTS: We identified 5 patients from 3 institutions who developed a white opacity in varying layers of the cornea, consistent with calcium deposition, during treatment with cenegermin. In all cases, the opacity occurred rapidly over the course of a few weeks after initiation of treatment. Histopathologic examination of the cornea from one corneal patient demonstrated extensive calcification of the stroma extending to 90% depth. Before treatment, all patients had stage 2 or 3 NK (Mackie classification). The deposits were visually significant in all patients and did not resolve after cessation of cenegermin. There were no differences in age, sex, etiology of the NK, corneal transplant status, or concurrent medications between the patients who developed a deposit and 15 other patients with stage 2 or 3 NK who did not. One patient was successfully treated with superficial keratectomy with ethylenediaminetetraacetic acid chelation, one patient underwent penetrating keratoplasty, and one patient received a Boston keratoprosthesis. CONCLUSIONS: We report the rapid onset of a corneal opacity after initiation of treatment with cenegermin in patients with stage 2 or 3 NK, consistent with acute calcific band keratopathy. This visually significant adverse finding has not previously been described. We could not identify any risk factors for development. We recommend close monitoring of patients receiving cenegermin therapy because the opacity may be irreversible and may require keratoplasty for visual rehabilitation.
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Calcinose/induit chimiquement , Cornée/effets des médicaments et des substances chimiques , Dystrophies héréditaires de la cornée/traitement médicamenteux , Opacité cornéenne/induit chimiquement , Facteur de croissance nerveuse/effets indésirables , Maladie aigüe , Adulte , Sujet âgé , Sujet âgé de 80 ans ou plus , Calcinose/diagnostic , Cornée/anatomopathologie , Opacité cornéenne/diagnostic , Femelle , Humains , Mâle , Facteur de croissance nerveuse/usage thérapeutique , Pronostic , Protéines recombinantes/effets indésirables , Protéines recombinantes/usage thérapeutique , Études rétrospectives , Biomicroscopie/méthodes , Tomographie par cohérence optique/méthodesRÉSUMÉ
Background: Glioblastoma (GBM) is one of the most aggressive types of brain cancer. GBM progression is closely associated with microglia activation; therefore, understanding the regulation of the crosstalk between human GBM and microglia may help develop effective therapeutic strategies. Elucidation of efficient delivery of microRNA (miRNA) via extracellular vesicles (EVs) and their intracellular communications is required for therapeutic applications in GBM treatment. Methods: We used human GBM cells (U373MG) and human microglia. MiRNA-124 was loaded into HEK293T-derived EVs (miR-124 EVs). Various anti-tumor effects (proliferation, metastasis, chemosensitivity, M1/M2 microglial polarization, and cytokine profile) were investigated in U373MG and microglia. Anti-tumor effect of miR-124 EVs was also investigated in five different patient-derived GBM cell lines (SNU-201, SNU-466, SNU-489, SNU-626, and SNU-1105). A three-dimensional (3D) microfluidic device was used to investigate the interactive microenvironment of the tumor and microglia. Results: MiR-124 EVs showed highly efficient anti-tumor effects both in GBM cells and microglia. The mRNA expression levels of tumor progression and M2 microglial polarization markers were decreased in response to miR-124 EVs. The events were closely related to signal transducer and activator of transcription (STAT) 3 signaling in both GBM and microglia. In 3D microfluidic experiments, both U373MG and microglia migrated to a lesser extent and showed less-elongated morphology in the presence of miR-124 EVs compared to the control. Analyses of changes in cytokine levels in the microfluidic GBM-microglia environment showed that the treatment with miR-124 EVs led to tumor suppression and anti-cancer immunity, thereby recruiting natural killer (NK) cells into the tumor. Conclusions: In this study, we demonstrated that EV-mediated miR-124 delivery exerted synergistic anti-tumor effects by suppressing the growth of human GBM cells and inhibiting M2 microglial polarization. These findings provide new insights toward a better understanding of the GBM microenvironment and provide substantial evidence for the development of potential therapeutic strategies using miRNA-loaded EVs.
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Glioblastome/génétique , microARN/génétique , Microglie/métabolisme , Tumeurs du cerveau/anatomopathologie , Lignée cellulaire tumorale , Systèmes de délivrance de médicaments/méthodes , Vésicules extracellulaires/génétique , Vésicules extracellulaires/métabolisme , Glioblastome/métabolisme , Cellules HEK293 , Humains , Activation des macrophages , Macrophages/métabolisme , microARN/métabolisme , Microfluidique , Microglie/physiologie , Microenvironnement tumoralRÉSUMÉ
There are extensive studies on the applications of extracellular vesicles (EVs) produced in cell culture for therapeutic drug development. However, large quantities of EVs are needed for in vivo applications, which requires high production costs and time. Thus, the development of new EV sources is essential to facilitate their use. Accordingly, plant-derived exosome-like nanovesicles are an emerging alternative for culture-derived EVs. Until now, however, few studies have explored their biological functions and uses. Therefore, it is necessary to elucidate biological activities of plant-derived exosome-like nanovesicles and harness vesicles for biomedical applications. Herein, cabbage and red cabbage were used as nanovesicle sources owing to their easy cultivation. First, an efficient method for nanovesicle isolation from cabbage (Cabex) and red cabbage (Rabex) was developed. Furthermore, isolated nanovesicles were characterized, and their biological functions were assessed. Both Cabex and Rabex promoted mammalian cell proliferation and, interestingly, suppressed inflammation in immune cells and apoptosis in human keratinocytes and fibroblasts. Finally, therapeutic drugs were encapsulated in Cabex or Rabex and successfully delivered to human cells, demonstrating the potential of these vesicles as alternative drug delivery vehicles. Overall, the current results provide strong evidence for the wide application of Cabex and Rabex as novel therapeutic biomaterials.
RÉSUMÉ
Sonodynamic therapy (SDT), wherein sonosensitizers irradiated with ultrasound (US) produce cytotoxic reactive oxygen species (ROS), has garnered great attention as a promising alternative to photodynamic therapy owing to the significantly increased depth of tissue penetration. The development of nanocarriers that can selectively deposit sonosensitizers into tumor tissues without systemic toxicity is crucial to facilitate the translation of SDT to clinical use. In this study, exosomes, a class of naturally occurring nanoparticles, were utilized as nanocarriers for safe and cancer-targeted delivery of a sonosensitizer, indocyanine green (ICG). The exosomes were surface-engineered with an active cancer-targeting ligand, folic acid (FA), to increase the cancer specificity of the ICG-loaded exosomes (ExoICG). The FA-conjugated, ICG-loaded exosomes (FA-ExoICG) greatly improved aqueous stability and cellular uptake of ICG, resulting in significantly increased ROS generation in breast cancer cells. As a result, the FA-ExoICG demonstrated greater sonotoxicity against cancer cells than ExoICG and free ICG. The in vivo study revealed that compared to ExoICG, more FA-ExoICG accumulated in tumors, and their pharmacokinetic properties were superior. Notably, tumor growth in mice was significantly suppressed, without systemic toxicity, by a single intravenous injection of the FA-ExoICG and subsequent US irradiation. Therefore, this study demonstrated that active cancer-targeted FA-ExoICG could serve as effective nanosonosensitizers for safe and targeted cancer treatment.
Sujet(s)
Antinéoplasiques/administration et posologie , Tumeurs du sein/traitement médicamenteux , Exosomes , Acide folique/administration et posologie , Vert indocyanine/administration et posologie , Nanoparticules/administration et posologie , Ultrasonothérapie/méthodes , Animaux , Apoptose , Tumeurs du sein/métabolisme , Tumeurs du sein/anatomopathologie , Mouvement cellulaire , Prolifération cellulaire , Femelle , Acide folique/composition chimique , Humains , Vert indocyanine/composition chimique , Souris , Souris de lignée BALB C , Souris nude , Nanoparticules/composition chimique , Espèces réactives de l'oxygène/métabolisme , Cellules cancéreuses en culture , Complexe vitaminique B/administration et posologie , Complexe vitaminique B/composition chimique , Tests d'activité antitumorale sur modèle de xénogreffeRÉSUMÉ
Non-small cell lung cancer (NSCLC) is one of the leading causes of death from cancer worldwide. The delivery and controlled regulation of miRNAs via exosomes is known as a potential therapeutic approach in the treatment of cancer. In this study, human cell-derived exosomes were used as delivery vehicles for miRNAs, and we investigated their anti-tumor and anti-angiogenic effects on NSCLCs that were cultured in 2D and 3D microfluidic devices. We demonstrated that exosomes that contained miRNA-497 (miR-497) effectively suppressed tumor growth and the expression of their associated genes, i.e., yes-associated protein 1 (YAP1), hepatoma-derived growth factor (HDGF), cyclin E1 (CCNE1), and vascular endothelial growth factor-A (VEGF-A), in A549 cells. Also, the level of VEGF-A-mediated angiogenic sprouting was decreased drastically in human umbilical vein endothelial cells (HUVECs) cultured in a microfluidic device. To mimic the in vivo-like tumor microenvironment of NSCLC, A549 cells were co-cultured with HUVECs in a single device, and miR-497-loaded exosomes were delivered to both types of cells. As a result, both the tube formation of endothelial cells and the migration of tumor decreased dramatically compared to the control. This indicated that miR-497 has synergistic inhibitory effects that target tumor growth and angiogenesis, so exosome-mediated miRNA therapeutics combined with the microfluidic technology could be a predictive, cost-efficient translational tool for the development of targeted cancer therapy.
Sujet(s)
Antinéoplasiques/pharmacologie , Carcinome pulmonaire non à petites cellules/traitement médicamenteux , Exosomes/métabolisme , Laboratoires sur puces , Tumeurs du poumon/traitement médicamenteux , microARN/pharmacologie , Techniques d'analyse microfluidique , Cellules A549 , Antinéoplasiques/métabolisme , Carcinome pulmonaire non à petites cellules/métabolisme , Carcinome pulmonaire non à petites cellules/anatomopathologie , Mouvement cellulaire/effets des médicaments et des substances chimiques , Prolifération cellulaire/effets des médicaments et des substances chimiques , Tests de criblage d'agents antitumoraux , Humains , Tumeurs du poumon/métabolisme , Tumeurs du poumon/anatomopathologie , microARN/métabolismeRÉSUMÉ
PURPOSE: To characterize the clinical features of patients with direct immunofluorescence (DIF)-negative mucous membrane pemphigoid (MMP). DESIGN: Retrospective case series. METHODS: Thirty-six patients who underwent a conjunctival biopsy for suspected MMP were included. Demographic and clinical information was collected. Main outcome measures included visual acuity, Foster stages, presence of extraocular involvement, history of autoimmune disease, and durations of follow-up. RESULTS: Thirty-two patients had a negative DIF. Of those, 2 had a positive DIF on repeat biopsy. Eleven showed progression of conjunctival scarring during a median follow-up of 42 months (range, 8-100 months) and were diagnosed with biopsy-negative MMP. Another 11 patients with a median follow-up of 54 months (range, 15-138 months) were diagnosed with cicatrizing conjunctivitis of other causes. The median visual acuity of patients with biopsy-negative MMP at presentation was significantly lower compared to patients with cicatrizing conjunctivitis of other causes (20/400 vs 20/40, P = .02). Conjunctival scarring score at presentation in both biopsy-positive and biopsy-negative MMP groups was significantly higher compared to patients with cicatrizing conjunctivitis of other causes (median Foster stage, 3 vs 1, P = .009; and 3 vs 1, P = .01, respectively). CONCLUSIONS: Patients with progressive cicatrizing conjunctivitis likely have MMP in the absence of alternate diagnoses. Our findings emphasize that suspicion for MMP must remain high for patients who have Foster stage 3 conjunctival scarring on presentation or worsening of scarring during follow-up, even in the setting of negative DIF.
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Maladies auto-immunes/diagnostic , Cicatrice/diagnostic , Conjonctivite/diagnostic , Technique d'immunofluorescence directe/méthodes , Pemphigoïde bénigne des muqueuses/diagnostic , Adulte , Sujet âgé , Sujet âgé de 80 ans ou plus , Antibiotiques antinéoplasiques/usage thérapeutique , Maladies auto-immunes/traitement médicamenteux , Maladies auto-immunes/physiopathologie , Biopsie , Cicatrice/traitement médicamenteux , Cicatrice/physiopathologie , Conjonctivite/traitement médicamenteux , Conjonctivite/physiopathologie , Cyclophosphamide/usage thérapeutique , Évolution de la maladie , Femelle , Études de suivi , Humains , Immunosuppresseurs/usage thérapeutique , Mâle , Adulte d'âge moyen , Acide mycophénolique/usage thérapeutique , Pemphigoïde bénigne des muqueuses/traitement médicamenteux , Pemphigoïde bénigne des muqueuses/physiopathologie , Études rétrospectives , Coloration et marquage/méthodes , Acuité visuelle/physiologieRÉSUMÉ
In vivo confocal microscopy (IVCM) has become a widely accepted imaging technique to study the human living cornea. It provides a unique opportunity to visualize the corneal tissue at the cellular level without damage and longitudinally observe its pathologic and normative changes. With rapidly evolving technology, there has been an abundance of interest in maximizing its potential to better understand the human cornea in health and disease. This is evidenced by a growing literature analyzing acquired and inherited corneal and also systemic diseases using corneal IVCM. This article provides a narrative review of IVCM and its applications. [Full article available at http://rimed.org/rimedicaljournal-2016-06.asp, free with no login].
Sujet(s)
Cornée/imagerie diagnostique , Kératite/imagerie diagnostique , Microscopie confocale/méthodes , Neuropathies périphériques/imagerie diagnostique , HumainsRÉSUMÉ
IMPORTANCE: Considering the potential clinical importance of focal lamina cribrosa (LC) defects as a characteristic structural feature in glaucoma and a risk factor for glaucomatous visual field progression, it may be helpful to know the structure of focal LC defects and the spatial relationship between them and glaucomatous optic disc changes such as neuroretinal rim thinning/notching and acquired pits of the optic nerve (APON). OBJECTIVE: To investigate structural and spatial relationships between focal LC defects and glaucomatous neuroretinal rim thinning/notching and APON. DESIGN: In a cross-sectional analysis of data from an ongoing, prospective, longitudinal study, serial enhanced-depth imaging (EDI) optical coherence tomographic (OCT) images of the optic nerve head were obtained from patients with glaucoma and reviewed for focal LC defects (laminar holes or disinsertions). Anterior laminar insertion points and edges of laminar holes or disinsertions were marked in EDI-OCT images, reconstructed 3-dimensionally, and superimposed on optic disc photographs. SETTING: A glaucoma referral practice. PARTICIPANTS: Two hundred thirty-nine eyes (120 patients) were examined. Fifty-four eyes were excluded because of an incomplete horizontal or vertical set of serial EDI-OCT images or poor-quality EDI-OCT images owing to media opacity, irregular tear film, or poor patient cooperation. Among the remaining 185 eyes, 40 (from 31 patients) had laminar holes or disinsertions and were included for analysis. MAIN OUTCOME MEASURES: Presence, extent, and location of laminar holes or disinsertions. RESULTS: Among 185 eyes, 11 laminar holes and 36 laminar disinsertions were found in 40 eyes. Superimposed images of the 3-dimensionally reconstructed focal LC defects and disc photographs showed that the outline of the LC defect corresponded almost precisely to that of clinical APON for 6 laminar holes and that the LC defect was much larger than and enclosed APON for 10 laminar disinsertions. The remaining 5 laminar holes and 26 laminar disinsertions corresponded to focal neuroretinal rim loss, with no evidence of APON in disc photographs. CONCLUSIONS AND RELEVANCE: Focal LC defects (laminar holes or disinsertions) are associated with neuroretinal rim loss and APON. The extent of LC defects can be visualized more effectively on EDI-OCT images than by clinical examination.
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Glaucome/diagnostic , Neurofibres/anatomopathologie , Papille optique/anatomopathologie , Atteintes du nerf optique/diagnostic , Cellules ganglionnaires rétiniennes/anatomopathologie , Adulte , Sujet âgé , Sujet âgé de 80 ans ou plus , Antihypertenseurs/usage thérapeutique , Études transversales , Femelle , Études de suivi , Glaucome/traitement médicamenteux , Humains , Traitement d'image par ordinateur , Imagerie tridimensionnelle , Pression intraoculaire , Mâle , Adulte d'âge moyen , Atteintes du nerf optique/traitement médicamenteux , Études prospectives , Tomographie par cohérence optique , Troubles de la vision/diagnostic , Champs visuelsRÉSUMÉ
Schwannoma is a proliferation of neoplastic Schwann cells. Whereas schwannomas of the head and neck region are common, intraocular tissues are rarely affected. Uveal schwannoma has been aptly called a "pseudomelanoma", reflecting the difficulty in its clinical distinction from uveal malignant melanoma. Most of our current knowledge on intraocular schwannoma is limited to case reports, short case series, and non-comprehensive literature reviews. Three isolated reports of uveal schwannoma with extrascleral extension exist in literature, but the prognostic significance of this growth pattern is unknown. We present a patient with choroidal schwannoma with extrascleral extension and review 46 previously reported cases of uveal schwannomas to delineate clinical and pathologic characteristics of these intraocular tumors with a specific emphasis on schwannoma with extraocular extension.
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Tumeurs de la choroïde/anatomopathologie , Neurinome/anatomopathologie , Maladies de la sclérotique/anatomopathologie , Marqueurs biologiques tumoraux/analyse , Tumeurs de la choroïde/imagerie diagnostique , Énucléation oculaire , Femelle , Humains , Imagerie par résonance magnétique , Imagerie multimodale , Invasion tumorale , Neurinome/imagerie diagnostique , Tomographie par émission de positons , Maladies de la sclérotique/imagerie diagnostique , Tomodensitométrie , Échographie , Acuité visuelle/physiologie , Jeune adulteRÉSUMÉ
Plasmacytomas are plasma cell neoplasms that rarely involve ocular adnexal tissues as a primary lesion or secondary manifestation of plasma cell myeloma. Only one case of plasmacytoma involving the lacrimal drainage system, to our knowledge, is described in the literature. The clinical presentation of ocular adnexal primary plasmacytoma typically relates to its mass effect. In this clinicopathologic report, we describe an unusual presentation of primary plasmacytoma of the lacrimal canaliculus as infectious canaliculitis.
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Actinomyces/isolement et purification , Actinomycose/diagnostic , Dacryocystite/diagnostic , Infections bactériennes de l'oeil/diagnostic , Tumeurs de l'oeil/anatomopathologie , Maladies de l'appareil lacrymal/anatomopathologie , Plasmocytome/anatomopathologie , Actinomycose/microbiologie , Actinomycose/thérapie , Sujet âgé , Marqueurs biologiques tumoraux/analyse , Association thérapeutique , Dacryocystite/microbiologie , Dacryocystite/thérapie , Infections bactériennes de l'oeil/microbiologie , Infections bactériennes de l'oeil/thérapie , Humains , Maladies de l'appareil lacrymal/microbiologie , Maladies de l'appareil lacrymal/thérapie , Mâle , Plasmocytome/microbiologie , Plasmocytome/thérapie , Dosimétrie en radiothérapie , Radiothérapie de haute énergieRÉSUMÉ
Calmodulin (CaM) is a ubiquitous transducer of intracellular Ca(2+) signals and plays a key role in the regulation of the function of all cells. The interaction of CaM with a specific target is determined not only by the Ca(2+)-dependent affinity of calmodulin but also by the proximity to that target in the cellular environment. Although a few reports of stimulus-dependent nuclear targeting of CaM have appeared, the mechanisms by which CaM is targeted to non-nuclear sites are less clear. Here, we investigate the hypothesis that MARCKS is a regulator of the spatial distribution of CaM within the cytoplasm of differentiated smooth-muscle cells. In overlay assays with portal-vein homogenates, CaM binds predominantly to the MARCKS-containing band. MARCKS is abundant in portal-vein smooth muscle ( approximately 16 microM) in comparison to total CaM ( approximately 40 microM). Confocal images indicate that calmodulin and MARCKS co-distribute in unstimulated freshly dissociated smooth-muscle cells and are co-targeted simultaneously to the cell interior upon depolarization. Protein-kinase-C (PKC) activation triggers a translocation of CaM that precedes that of MARCKS and causes multisite, sequential MARCKS phosphorylation. MARCKS immunoprecipitates with CaM in a stimulus-dependent manner. A synthetic MARCKS effector domain (ED) peptide labelled with a photoaffinity probe cross-links CaM in smooth-muscle tissue in a stimulus-dependent manner. Both cross-linking and immunoprecipitation increase with increased Ca(2+) concentration, but decrease with PKC activation. Introduction of a nonphosphorylatable MARCKS decoy peptide blocks the PKC-mediated targeting of CaM. These results indicate that MARCKS is a significant, PKC-releasable reservoir of CaM in differentiated smooth muscle and that it contributes to CaM signalling by modulating the intracellular distribution of CaM.