Disease Modelling

• Ex vivo gene therapy


  Can be used for haematopoietic stem cells
• In vivo gene therapy

  • Can use adenovirus
  • Can use adeno-associated virus
• Novel strategies


  • Therapeutic use of embryonic stem cells
  • Therapeutic use of induced pluripotent stem cells
  • Therapeutic genome editing
  • Germ-line gene therapy
• In vitro models are based on our knowledge about affected tissues and cell types and the ability to study these cells in culture
• Analysis of a single type of cells is often insufficient in pathophysiological context because interaction between cells of different types can be essential
• Co-culture systems may overcome this limitation
• Though advanced organoid cell culture systems have been developed, animal experiments are still needed to assess systemic effects before clinical tests can be started
• Embryonic development


  Stages of development from fertilized egg to fully formed organism
• Cell potential


  The ability of a cell to differentiate into different cell types
• How pluripotent stem cells are isolated

  1. Cells from healthy individuals: Embryonic stem cells isolated after IVF, cultured and gene edited or screened for spontaneous chromosome aberrations

  2. Cells from known mutation carriers: Embryonic stem cells isolated after pre-implantation analysis, generated by nuclear transfer, or somatic cells reprogrammed to induce pluripotency
• How pluripotent stem cells are induced

  1. Fibroblast nuclei reprogrammed to produce self-regenerating ES-like cells known as induced pluripotent stem (iPS) cells

  2. Skin fibroblasts transfected with genes encoding pluripotency associated transcription factors or transduced by a cocktail of the transcription factor proteins
• Induced pluripotent stem (iPS) cells


  • Can be directed to differentiate along various pathways to give diverse cell types with multiple biomedical applications including autologous cell therapy, ex vivo gene therapy, drug screening, and human cellular models of disease
• First steps in the molecular characterisation of diseases and pathways would be done in cell culture
• Cell culture allows high-throughput drug screening experiments if cellular changes can be studied in a systematic approach and if sufficient numbers of cells can be obtained and amplified
• Pluripotent stem cells offer vast opportunities for the generation of cellular models for genetic diseases
• Therapeutic cloning


  A cell nucleus is transplanted into an enucleated egg, and the resulting blastocyst will be genetically identical with that of the donating patient
• Cellular differentiation


  The process by which a less specialized cell becomes a more specialized cell type
• Induced pluripotent stem (iPS) cells


  • Essentially equivalent to embryonic stem cells
• Directed differentiation of pluripotent human cells

  • Can be engineered along the lines of naturally occurring reprogramming using defined growth factors and culture conditions
• Organoids


  • PSC-derived cell lines and mixtures of different cell types can be used to generate human organoids
• Rodent models are advantageous for studying monogenic diseases and testing treatments and systemic responses
• Animal models other than rodents are needed to study diseases affecting cognitive and/or social abilities, and to study more complex genetic and physiological parameters
• Important ethical questions may arise from gene (genome) cloning and targeting
• Pluripotent stem cells


  Stem cells that have the ability to differentiate into any cell type in the body, except for those that form the placenta.
• Induced pluripotent stem (iPS) cells

  Pluripotent stem cells that are generated in a laboratory by reprogramming the nuclei of adult cells, such as fibroblasts.