CRISPR/Cas9 system and Gene editing therapy

Gene therapy, to be brief, is delivering corrective gene materials into cells to treat or alleviate the symptom of disease, so far, including gene editing therapy mediated by CRISPR/Cas sytem, ZFN or TALEN etc., and gene replacement, such as lentivirus/adenovirus/AAV-mediated gene expression.

What is gene transfection

In general, transfection is the process of delivering nucleic acids, such as DNA and RNA into eukaryotic cells, resulting in the expression or production of proteins or down-regulation of the targeted protein. 

Transfection in vitro

Transfection in vitro can be mediated by the non-viral reagents (such as polymer, liposome, nano-particle) or viral vectors (such as lentivirus, adenovirus and AAV).

Transfection in vivo

Transfection in vitro can be mediated by the non-viral reagents (such as liposome, polymer, nano-particle) or viral vectors (such as lentiviruses, adenovirus and AAV).

Small interfering RNA (siRNA) transfection

Small interfering RNA (siRNA) contains 21-25 nucleotides, specific for target RNA. Once entry into cells, siRNAs can be recruited into a multi-protein complex, known as RNA induced silencing complex (RISC), which interacts with the target RNA to mediate mRNA degradation, thus knock-down or suppress the expression of target gene.

How to achieve accurate and efficient gene transfection of animal target-organs?

Gene Transfection, in layman's words, mainly refers to the increase and decline of gene expression (i.e. gain of function OR loss of function). A classic animal model of gene intervention--genetically engineered mice.Genetically engineered mice included transgenic mice (TG mouse), Knockout mice (KO mouse), and typed mice (KI mouse). In the introduction of CRE-LOXP system, the tissue-specific TG and KO mice were developed.

What is the difference between Ex vivo, In vivo and In vitro?

In vitro (Latin: in glass) studies in experimental biology are those that are conducted using components of an organism that have been isolated from their usual biological surroundings in order to permit a more detailed or more convenient analysis than can be done with whole organisms. Colloquially, these experiments are commonly called "test tube experiments". In contrast, in vivo work is that which is conducted with living organisms in their normal, intact state, while ex vivo studies are conducted on functional organs that have been removed from the intact organism.