RESUMEN
Megalin is a multiligand, endocytic receptor that is important for the normal, proximal tubule reabsorption of filtered proteins, hormones, enzymes, essential nutrients, and nephrotoxins. Megalin dysfunction has been associated with acute, as well as chronic kidney diseases. Tubular proteinuria has been observed following unilateral ureteral obstruction (UUO), suggesting megalin dysfunction; however, the pathophysiological mechanism has not been determined. To identify potential regulators of megalin expression, we examined renal microRNAs (miRNAs) expression and observed an upregulation of microRNA-148b (miR-148b) in obstructed mouse kidneys 7 days after UUO, which was associated with a significant reduction in proximal tubule megalin expression and accumulation of megalin ligands. By in silico miRNA target prediction analysis, we identified megalin messenger RNA (mRNA) as a potential target of miR-148b and confirmed using a dual-luciferase reporter assay that miR-148b targeted the 3'-untranslated region of the megalin gene. Transfection of LLC-PK1 cells with miR-148b mimic reduced endogenous megalin mRNA and protein levels in a concentration-dependent manner, while transfection with miR-148b inhibitor resulted in an increase. Our findings suggest that miR-148b directly downregulates megalin expression and that miR-148b negatively regulates megalin expression in UUO-induced kidney injury. Furthermore, the identification of a miRNA regulating megalin expression may allow for targeted interventions to modulate megalin function and proximal tubule uptake of proteins, as well as other ligands.
Asunto(s)
Enfermedades Renales/metabolismo , Túbulos Renales Proximales/metabolismo , Proteína 2 Relacionada con Receptor de Lipoproteína de Baja Densidad/metabolismo , MicroARNs/metabolismo , Obstrucción Ureteral/complicaciones , Regiones no Traducidas 3' , Animales , Sitios de Unión , Modelos Animales de Enfermedad , Regulación hacia Abajo , Células HEK293 , Humanos , Enfermedades Renales/etiología , Enfermedades Renales/genética , Enfermedades Renales/patología , Túbulos Renales Proximales/patología , Células LLC-PK1 , Ligandos , Proteína 2 Relacionada con Receptor de Lipoproteína de Baja Densidad/genética , Masculino , Ratones Endogámicos C57BL , MicroARNs/genética , ARN Mensajero/genética , ARN Mensajero/metabolismo , Porcinos , Factores de Tiempo , Transcripción Genética , TransfecciónRESUMEN
In this work, a theranostic nanoparticle was developed for multimodal imaging and siRNA delivery. The core of the nanoparticles (NP) was formed by encapsulation of superparamagnetic iron oxides and indocyanine green in a PLGA matrix to serve as a multimodal probe for near-infrared (NIFR) and magnetic resonance (MR) imaging. The surface of the particle was coated with polyethylenimine (PEI) for siRNA delivery. Macrophages efficiently took up the nanoparticles and emitted strong NIFR and MR contrast. When transfected with siRNA targeting the pro-inflammatory enzyme cyclooxygenase-2 (COX-2), significant down-regulation of COX-2 was achieved in activated macrophages. Furthermore, after injection into a unilateral ureteral obstruction (UUO)-induced kidney injury model, NIFR and MRI imaging revealed accumulation of nanoparticles in the injury kidney. In addition, in vivo silencing of COX-2 was achieved by NP/PEI/siCOX-2, which further attenuated kidney injury. Our theranostic platform represents a promising approach for simultaneous diagnosis and treatment of inflammatory diseases.
Asunto(s)
Portadores de Fármacos/química , Ácido Láctico/química , Nanopartículas/química , Ácido Poliglicólico/química , ARN Interferente Pequeño/administración & dosificación , Insuficiencia Renal/terapia , Animales , Ciclooxigenasa 2/genética , Macrófagos/metabolismo , Imagen por Resonancia Magnética/métodos , Masculino , Ratones , Nanopartículas/ultraestructura , Imagen Óptica/métodos , Copolímero de Ácido Poliláctico-Ácido Poliglicólico , Células RAW 264.7 , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/uso terapéutico , Tratamiento con ARN de Interferencia/métodos , Insuficiencia Renal/genética , Nanomedicina Teranóstica/métodos , Transfección/métodosRESUMEN
A syndemic is the co-existence of two or more health problems (including both social and biological features) that adversely influence each other with negative consequences on disease outcomes and perpetuation of inequalities. The syndemic approach can be applied to better understand the course of rheumatic musculoskeletal diseases (RMD) involving the study of adverse biological pathways and social determinants of health (SDH) all under the same framework. Identifying if a syndemic exists within RMDs may include investigating the synergic interactions between comorbidity (e.g., diabetes, obesity, chronic kidney diseases) and the concomitant of other adverse conditions (e.g., drug non-adherence, substance abuse), along with SDHs such as low household income, unemployment, low education, limited access to health care, as well as racial/ethnic discrimination. For decades, the understanding of RMDs progression has been based on causality, rather than investigating the kaleidoscopic web of connections that can potentially influence a disease course. The co-existence of health burdens in vulnerable populations, including those with RMD, specifically in certain socioeconomic groups, calls for new ways and strategies of thinking to improve our understanding of risk factors and co-morbidities to offer tailored interventions for clinical medicine and public health policy.