Respuesta inmune y terapia gó©nica con vectores virales adenoasociados / Immune response and gene therapy with adenoassociated viral vectors

En los ó;ºltimos aó;±os la terapia gó;©nica se ha posicionado como una opció;n real y segura en el desarrollo de alternativas terapó;©uticas para la cura y la prevenció;n de diferentes enfermedades. Consiste en la inserció;n de material genó;©tico en un tejido o có;©lula defectuosa, mediante el uso de un vector. Existen varias consideraciones para seleccionar el vector más apropiado, incluyendo el potencial de unió;n y entrada a la có;©lula diana, la capacidad de transferencia del material genó;©tico al nó;ºcleo, la habilidad de expresió;n del inserto y la ausencia de toxicidad. En el panorama actual, los vectores virales más utilizados son los derivados de los virus adenoasociados (AAV). Características como su bioseguridad, baja toxicidad y tropismo selectivo, han posibilitado su evaluació;n como opció;n terapó;©utica en un amplio nó;ºmero de enfermedades monogó;©nicas o complejas. A pesar de sus ventajas, los vectores AAV presentan inconvenientes, siendo el más importante la respuesta inmune del paciente al vector, especialmente la respuesta mediada por anticuerpos neutralizantes (NAb). Los NAb disminuyen la transducció;n del vector e impiden la expresió;n del gen que transporta, limitando su aplicació;n clínica. Por lo tanto, identificar y cuantificar la presencia y actividad de los NAbs, es el primer paso en cualquier protocolo de terapia gó;©nica con vectores AAV. La presencia de NAb depende principalmente de la exposició;n al virus en la naturaleza y varía drásticamente segó;ºn edad, localizació;n geográfica y estado de salud de la persona evaluada.

In recent years, gene therapy has been positioned as a real and safe option in the development of therapeutic alternatives for the cure and prevention of different diseases. It consists in the insertion of genetic material in a defective tissue or cell, through the use of a vector. There are several considerations for selecting the most appropriate vector, including the potential for binding and entry to the target cell, the ability of the genetic material to transfer to the nucleus, the ability to express the insert, and the absence of toxicity. In the current scenario, the most commonly used viral vectors are those derived from adeno-associated viruses (AAV). Characteristics such as biosafety, low toxicity and selective tropism have enabled its evaluation as a therapeutic option in many monogenic or complex diseases. Despite their advantages, AAV vectors have drawbacks, the most important being the patient’s immune response to the vector, especially the response mediated by neutralizing antibodies (NAb). NAbs decrease the transduction of the vector and prevent the expression of the gene it transports, limiting its clinical application. Therefore, identifying and quantifying the presence and activity of NAbs is the first step in any gene therapy protocol with AAV vectors. The presence of NAbs depends mainly on exposure to the virus in nature and varies drastically according to age, geographic location and health status of the person evaluated.

Efficiency of Gene Transfection with Adeno-associated Viral Vector or Lentiviral Vector in Bone Marrow Derived Mesenchymal Stem Cells / 中国康复理论与实践

Objective To compare 2 kinds of commonly used viral vectors, adeno-associated viral (AAV) vector and lentiviral (LV) vec-tor in the gene transfection for bone marrow derived mesenchymal stem cells (MSCs). Methods MSCs were isolated with density gradient (lymphocytes seperation) and identified with HE staining and immunocytochemistory staining for Nestin. The proliferation of BMSCs was detected with BrdU labeling. AAV mediated gene transfection was carried out through recombinant AAV-LacZ viral particles. For LV medi-ated gene transfection, the LV particles were used directly. The transfection efficiency was estimated withβ-gal staining and green fluores-cent protein under the fluorescent microscope respectively. Results MSCs was successfully isolated from the bone marrow. HE staining showed that MSCs was with big nucleus, 1-3 nucleoli, and high nucleocytoplasmic ratio. BrdU labeling suggested that MSCs were prolifer-ating. Some MSCs expressed Nestin. The gene transfection efficiency mediated with AAV vector was 49.1%, and it was 91.4%with LV vec-tor (P<0.01). Conclusion The LV vector is more efficient on gene transfection than AAV vector.

Hope for the patients with retinitis pigmentosa / 中华实验眼科杂志

Retinitis pigmentosa (RP) is a hereditary disease characterized by the progressive loss of photoreceptor cells. Disease pathology primarily affects rod photoreceptor cells first but light-insensitive cone photoreceptor bodies can survivor longer. Delivered by adeno-associated viral vector or lentiviral vector, expression of microbial-type rhodopsin, channelrhodopsin-2 or archaebacterial halorhodopsin in the survived retinal cells can substitute for the native phototransduction cascade in mouse models of retinitis pigmentosa. It can also restore light sensitivity and activate all retinal cone pathways and drive sophisticated retinal circuit functions. Thus, expression of channelrhodopsins or halorhodopsin might be a potential strategy for the restoration vision of patients with RP.