RESUMEN
Key Clinical Message: In non-healing ulcers with a previous history of burns, clinicians should have a high index of suspicion for Marjolin's ulcer and a low threshold for biopsy, irrespective of age. Abstract: Marjolin's ulcer is a rare malignancy arising from chronic inflammation and commonly manifests in burn scars. Thus, in cases of chronic wounds or non-healing ulcers, health professionals should have a high index of suspicion and a low threshold for biopsy, irrespective of age. Early diagnosis and timely management of tumors can improve the prognosis and overall survival rate. Moreover, further studies are needed to develop an evidence-based management approach for Marjolin's ulcer.
RESUMEN
A 35 years old male patient presented in the hospital with complaints of left-sided facial swelling, blindness in the left eye, and left eye proptosis. He had a concomitant history of diabetic ketoacidosis. Magnetic resonance imaging was advised, which revealed infected tissue of the left cheek, optic nerve infarction, intracranial extension, and leptomeningeal involvement by the disease process.
RESUMEN
Double cortex syndrome is an uncommon familial syndrome with X-linked dominant inheritance and most commonly presents with developmental delay and seizures. We present a case of a 14-year-old girl who came to neurology department of the hospital with severe generalized tonic-clonic fits and loss of consciousness. The mother of child gave history of uneventful antenatal period and labor. There was history of immediate cry and normal APGAR score. She was achieving milestones normally until at the age of 3 years when she suffered decline in her speech and vision. She had problems with learning with lack of concentration during her schooling. Physical examination was also unremarkable. Her lab values including complete blood count, serum calcium, and arterial blood gas tests, all were within normal limits. Electroencephalogram showed significant changes suggestive of epilepsy. Magnetic resonance imaging of brain showed continuous band of gray matter that was located deep and paralleling the cortex in both cerebral hemispheres suggestive of band heterotopia or double cortex syndrome. She was discharged and prescribed antiepileptics; and was advised regular outpatient follow-up.
RESUMEN
Joubert syndrome is a rare neurological and developmental malfunction represented by decreased muscle tone, ataxia, and delayed developmental milestones. Joubert syndrome-related disorders, besides central nervous system, can involve other systems and thus can lead to multi-organ malfunction. We report a case of pure Joubert syndrome who presented with developmental delay, decreased muscle tone, and ataxia. Identification of molar tooth sign on magnetic resonance imaging studies assisted to make a definitive diagnosis. Detailed examination revealed no other significant findings of any organ of the body. Patient was managed conservatively with symptomatic treatment. Although these types of cases are rarely encountered, they can lead to multiple organ disabilities. Therefore, clinicians should always keep this diagnosis in mind whenever an infant presents with the aforementioned neurodevelopmental symptoms.
RESUMEN
BMP2 signaling and RUNX2 regulatory pathways converge for transcriptional control of bone formation in vivo. SMAD proteins are recruited to RUNX2 regulatory complexes via an overlapping nuclear matrix targeting signal/Smad interacting domain sequence (391-432) in Runx2. To establish the contribution of RUNX2-SMAD interaction to osteoblastogenesis, we characterized a number of point mutants. Only a triple mutation of amino acids 426-428 (HTY-AAA) results in loss of RUNX2 interactions with either BMP2- or TGF-beta- responsive SMADs and fails to integrate the BMP2/TGF-beta signal on target gene promoters. In a Runx2 null cell reconstitution assay, the HTY mutant did not activate the program of osteoblast differentiation (alkaline phosphatase, collagen type 1, osteopontin, bone sialoprotein and osteocalcin) in response to BMP2 signaling. Thus, subnuclear targeting function and formation of a RUNX2-SMAD osteogenic complex are functionally inseparable. Taken together, these studies provide direct evidence that RUNX2 is essential for execution and completion of BMP2 signaling for osteoblast differentiation.
Asunto(s)
Aminoácidos/metabolismo , Proteína Morfogenética Ósea 2/farmacología , Diferenciación Celular/efectos de los fármacos , Subunidad alfa 1 del Factor de Unión al Sitio Principal/química , Subunidad alfa 1 del Factor de Unión al Sitio Principal/metabolismo , Osteoblastos/citología , Proteínas Smad/metabolismo , Secuencia de Aminoácidos , Animales , Células HeLa , Humanos , Ratones , Datos de Secuencia Molecular , Proteínas Mutantes/metabolismo , Señales de Localización Nuclear/metabolismo , Osteoblastos/efectos de los fármacos , Osteoblastos/metabolismo , Transducción de Señal/efectos de los fármacos , Relación Estructura-Actividad , Factor de Crecimiento Transformador beta/metabolismoRESUMEN
Two regulatory pathways, bone morphogenetic protein (BMP)/transforming growth factor-beta (TGFbeta) and the transcription factor RUNX2, are required for bone formation in vivo. Here we show the interdependent requirement of these pathways to induce an osteogenic program. A panel of Runx2 deletion and point mutants was used to examine RUNX2-SMAD protein-protein interaction and the biological consequences on BMP2-induced osteogenic signaling determined in Runx2 null cells. These cells do not respond to BMP2 signal in the absence of Runx2. We established that a triple mutation in the C-terminal domain of RUNX2, HTY (426-428), disrupts the RUNX2-SMAD interaction, is deficient in its ability to integrate the BMP2/TGFbeta signal on promoter reporter assays, and is only marginally functional in promoting early stages of osteoblast differentiation. Furthermore, the HTY mutation overlaps the unique nuclear matrix targeting signal of Runx factors and exhibits reduced subnuclear targeting. Thus, formation of a RUNX2-SMAD osteogenic complex and subnuclear targeting are structurally and functionally inseparable. Our results establish the critical residues of RUNX2 for execution and completion of BMP2 signaling for osteoblastogenesis through a mechanism that requires RUNX2-SMAD transcriptional activity.
Asunto(s)
Proteínas Morfogenéticas Óseas/metabolismo , Subunidad alfa 1 del Factor de Unión al Sitio Principal/metabolismo , Osteogénesis , Transducción de Señal , Proteínas Smad/metabolismo , Factor de Crecimiento Transformador beta/metabolismo , Secuencia de Aminoácidos , Animales , Biomarcadores , Proteína Morfogenética Ósea 2 , Diferenciación Celular , Subunidad alfa 1 del Factor de Unión al Sitio Principal/química , Subunidad alfa 1 del Factor de Unión al Sitio Principal/deficiencia , Subunidad alfa 1 del Factor de Unión al Sitio Principal/genética , Células HeLa , Humanos , Ratones , Ratones Noqueados , Datos de Secuencia Molecular , Mutación/genética , Osteoblastos/citología , Osteoblastos/metabolismo , Fenotipo , Unión ProteicaRESUMEN
We have developed new, synthetic vector formulations that display high efficiency of gene transfer to vascular cells and tissues. The formulations comprise cationic liposomes and cationic, receptor-targeting peptides that self assemble on mixing with plasmid DNA into receptor-targeted nanocomplexes (RTNs). One such RTN formulation was optimal for transfection of primary smooth muscle cells (LYD-1), while a second was optimal for transfection of rabbit aortic explants (LYD-2). In both RTNs, the peptide was a 16-lysine motif linked to the targeting sequence CYGLPHKFCG via a short spacer sequence. The major difference between LYD-1 and LYD-2 lay in the cationic lipid component, where LYD-1 contained ditetradecyl trimethyl ammonium (DTDTMA), an unsaturated, cationic lipid with a 14-carbon alkyl tail, whereas LYD-2 contained 2,3-dioleyloxypropyl-1-trimethyl ammonium chloride (DOTMA), a cationic lipid with an 18-carbon unsaturated alkyl tail. LYD-2 transfections of aortic explants were effective with incubations performed at room temperature for as little as 30 minutes, with either saline or glucose-based solutions. Transgene expression in the explants peaked at 5 days and persisted for 14 days. The kinetics of transfected gene expression, along with the efficacy of transfection with short incubation times, indicate that these new formulations may be useful tools in the development of molecular therapies for cardiovascular diseases.
Asunto(s)
Aorta/citología , Músculo Liso Vascular/metabolismo , Nanopartículas/química , Receptores de Superficie Celular/genética , Animales , Células Cultivadas , Técnicas de Transferencia de Gen , Vectores Genéticos/genética , Humanos , Cinética , Liposomas/química , Masculino , Músculo Liso Vascular/citología , Técnicas de Cultivo de Órganos , Péptidos/química , Plásmidos/química , Plásmidos/genética , Reacción en Cadena de la Polimerasa , Conejos , Porcinos , Transfección/métodosRESUMEN
The coordinated activity of Runx2 and BMP/TGFbeta-activated Smads is critical for formation of the skeleton, but the precise structural basis for the Runx2/Smad interaction has not been resolved. By deletion mutagenesis, we have defined the Runx2 motif required for physical and functional interaction with either BMP or TGFbeta responsive Smads. Smad responsive transcriptional activity was retained upon deletion of the C-terminus to amino acid (aa) 432 but lost with deletion to aa 391. Thus the Smad interacting domain (SMID) of Runx2 (432-391) is embedded in the well-defined nuclear matrix targeting signal (NMTS) that mediates intranuclear trafficking. The SMID suffices as an interacting module when fused to the heterologous Gal-4 protein. Formation of the Runx2 and Smad complex is dependent on Runx2 phosphorylation through the MAPK signaling pathway, as determined by co-immunoprecipitation studies. We established that all SMID/NMTS deficient Runx2 mutants do not show in situ association with Smad in the nucleus nor do they support BMP2-mediated osteogenic induction of the mesenchymal C2C12 cell line. Thus, we provide direct evidence that the SMID/NMTS domain (391-432) of Runx2 is essential for BMP2-mediated osteoblast differentiation. Our findings suggest that TGFbeta/ BMP2 signaling, MAPK dependent phosphorylation, and Runx2 subnuclear targeting converge to induce the osteogenic phenotype.
Asunto(s)
Proteínas Morfogenéticas Óseas/metabolismo , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Osteocitos/fisiología , Fosfoproteínas/metabolismo , Células Madre Pluripotentes/fisiología , Transactivadores/metabolismo , Factores de Transcripción/genética , Factor de Crecimiento Transformador beta/metabolismo , Animales , Proteína Morfogenética Ósea 2 , Proteínas Morfogenéticas Óseas/genética , Linaje de la Célula , Núcleo Celular/metabolismo , Subunidad alfa 1 del Factor de Unión al Sitio Principal , Proteínas de Unión al ADN/química , Eliminación de Gen , Células HeLa , Humanos , Riñón/citología , Ratones , Mutagénesis , Osteocitos/citología , Células Madre Pluripotentes/citología , Mutación Puntual , Estructura Terciaria de Proteína , Transducción de Señal/efectos de los fármacos , Transducción de Señal/fisiología , Proteína Smad5 , Factor de Transcripción AP-2 , Factores de Transcripción/química , Factores de Transcripción/metabolismo , Transcripción Genética/efectos de los fármacos , Transcripción Genética/fisiología , Factor de Crecimiento Transformador beta/genéticaRESUMEN
It has been shown previously that osteoblast differentiation and maintenance of bone mass are impaired in endothelial nitric oxide synthase gene knockout mice. The present study shows by analysis of messenger RNA expression that the transcription factor Cbfa-1/Runx-2 and the bone matrix protein osteocalcin, which are fundamental to osteoblast differentiation, are significantly reduced in neonatal calvarial osteoblasts from these gene knockout mice. Expression of these genes could be restored to wild-type levels by exogenous supply of the photoactivatable nitric oxide donor potassium nitrosylpentachlorouthenate, but this was dependent on the timing of its activation and recovery in gene expression was only evident during the latter stages of osteoblast differentiation associated with its mineralizing activity. Calvarial, femoral/pelvic, spinal, and total bone mineral density, together with bone microhardness and expression of osteocalcin in whole femurs, were all reduced significantly in gene knockout mice at 8 weeks of age, but not at 12 weeks, where all of these indices of bone integrity were comparable to wild type. In accordance with these temporal effects, reduced bone mineral density, bone microhardness, and osteocalcin expression could be restored to normal, wild-type values after 21 days in vivo administration of the nitric oxide donor glyceryl trinitrate to 4-week-old endothelial nitric oxide synthase knockout mice, but there was no significant effect in older animals. Taken together, these results further demonstrate the importance of endothelial nitric oxide synthase in the regulation of osteoblast metabolism. In particular, they show that nitric oxide is involved in co-ordinating specific phases of osteoblast differentiation and bone formation: this could be relevant to its therapeutic actions on bone turnover.