BIOTECHNOLOGY AND MEDICINE Lecture 8

1. BIOTECHNOLOGY AND MEDICINELecture 8 Madam NoorulnajwaDiyanaYaacob PPK Bioproses

2. Lesson Contents 1. Detecting and Diagnosing Human Disease Conditions 2. Medical Products and Applications of Biotechnology 3. The Potential of Regenerative Medicine 4. Gene Therapy 5. The Human Genome Project

3. 1. Detecting and Diagnosing Human Disease Conditions Models of Human Disease • A number of human genetic diseases also occur in model organisms • Can therefore use model organisms to identify disease genes and test gene therapy and drug-based therapeutic approaches to check their effectiveness and safety in preclinical studies

4. 1. Detecting and Diagnosing Human Disease Conditions ……. cont. • Extremely important because we cannot manipulate human genetics for experimental purposes • Extremely important because we cannot manipulate human genetics for experimental purposes • Many genes in different species have been shown to be similar to human genes based on DNA sequence – called homologs

5. Detecting and Diagnosing Human Disease Conditions ……. cont.

6. Escherichia coli -  gram-negative model organism Mus musculus – house mouse

7. Male (left) and female Drosophila melanogaster

8. Detecting and Diagnosing Human Disease Conditions ……. cont. Biomarkers for Disease Detection • Early detection of disease is critical for providing the best treatment and improving the odds of survival • With the right diagnostic tools, may be possible to detect most every disease at an early stage • Biomarkers – typically proteins produced by diseased tissue or proteins whose production is increased when a tissue is diseased • PSA, prostate-specific antigen

9. Detecting and Diagnosing Human Disease Conditions ……. cont. Detecting Genetic Diseases • Testing for chromosome abnormalities • Amniocentesis - fetus is 16 weeks of age • Take a sample of amniotic fluid • Create a karyotype • Chronic villus sampling (CVS) – fetus is 8-10 weeks old • Remove a small portion of a layer of cells called the chronic villus that helps form the placenta • Create a karyotype

10. Detecting and Diagnosing Human Disease Conditions ……. cont.

11. Detecting and Diagnosing Human Disease Conditions ……. cont. Detecting Genetic Diseases • Testing for chromosome abnormalities • Fluorescence in situ hybridization (FISH) – new technique for karyotyping • Useful for identifying missing chromosomes and extra chromosomes, but much easier to detect defective chromosomes

12. Definition Karyotypes describe the number of chromosomes, and what they look like under a light microscope. A karyotype is an organized profile of a person's chromosomes. In a karyotype, chromosomes are arranged and numbered by size, from largest to smallest. This arrangement helps scientists quickly identify chromosomal alterations that may result in a genetic disorder.

13. Detecting and Diagnosing Human Disease Conditions ……. cont. Testing for chromosome abnormalities

14. 2.Medical Products & Applications of Biotechnology …….. cont. 1. Pharmacogenomics – Customized Medicine • Pharmacogenetics is referred to the study of genetics influence on individual respond to drugs. • Designing the most effective drug therapy and treatment strategies based on the specific genetic profile of a patient • Individuals can react differently to the same drugs • Different degrees of effectiveness and side effects because of genetic polymorphisms

15. 2.Medical Products & Applications of Biotechnology …….. cont.

16. 2.Medical Products & Applications of Biotechnology …….. cont. 2. Improved Drug Delivery • Maximize drug effectiveness • Drug solubility, drug breakdown, drug elimination • Microspheres – tiny particles that can be filled with drugs. • Average particle size from 1 to 50 microns • Made from materials that closely resemble lipids found in cell membranes • Mist sprayed in the nose to treat lung cancer and other respiratory illnesses; anticancer drugs; anesthetics for pain management

17. 2.Medical Products & Applications of Biotechnology …….. cont. • Nanotechnology and Nanomedicine • Nanotechnology – involved in designing, building, and manipulating structures at the nanometer scale • nm is 1 billionth of a meter • Nanomedicine – applications of nanotechnology to improve human health • Nanodevices to monitor blood pressure, blood oxygen levels, hormone concentrations • Nanoparticles that can unclog arteries, detect and eliminate cancer cells; smart drugs that could seek out and target specific cells

18. 2.Medical Products & Applications of Biotechnology …….. cont.

19. MRI contrast agent is a group of contrast media/substance used to improve the visibility of internal body structures in medical imaging, e.g. magnetic resonance imaging (MRI) • Therapeutic: Relating to drug/medicine used for disease treatment.

20. 2.Medical Products & Applications of Biotechnology …….. cont. • Vaccines and Therapeutic Antibodies • Cancer vaccines – injected with cancer cell antigens to stimulate immune system to attack cancer cells • Vaccine for Alzheimer’s disease • Monoclonal Antibodies – purified antibodies that are very specific for certain molecules • Cancer cells, arthritis, and Alzheimer’s Disease • Treat addiction to harmful drugs

21. 2.Medical Products & Applications of Biotechnology …….. cont.

22. Antibodies - Are proteins found in blood serum which have specific reactivity with the corresponding antigen. • Antigens - Are substances that when introduced into the body stimulates the production of an antibody. Antigens include toxins, bacteria, foreign blood cells, and the cells of transplanted organs. • Monoclonal antibody - Monoclonal antibodies are proteins produced in the laboratory from a single clone of a B cell, the type of cells of the immune system that make antibodies

23. 3. Regenerative Medicine • Regenerative Medicine – growing cells and tissues that can be used to replace or repair defective tissues and organs

24. 3. Regenerative Medicine 1. Cell and Tissue Transplant • Fetal tissue grafts • Organ transplantation • Cellular therapeutics

25. 3. Regenerative Medicine • Fetal tissue graft/implant is a therapy where tissue from fetus is implanted to a patient for treatment of disease. • Fetal tissue is unique since it is fast growing and has a lower possibility of rejection from the host's cells. • Use for treating Parkinson’s disease, Alzheimer’s disease

26. 3. Regenerative Medicine 2. Tissue Engineering • May provide tissues and organs that can be used to replace damaged or diseased tissues • 1990s Dr. Charles Vacanti revealed a mouse with an engineered ear growing on its back • Seeded with cells from a cow • Just the outer ear without the inner ear structures that actually detect sound • Human bladders, rudimentary kidney

28. Cell therapy - describes the process of introducing new cells into a tissue in order to treat a disease. Cell therapies often focus on the treatment of hereditary diseases.

29. 4. Regenerative Medicine Stem Cell Technologies • What are stem cells? • Fertilization of egg by sperm results in a zygote • Zygote divides rapidly to form a compact ball of cells called a morula • Morula develops into embyro consisting of a small hollow cluster of cells called a blastocyst

30. A morula is an embryo at an early stage of embryonic development.

31. What are stem cells? • Two layers to the blastocyst • Outer layer forms the placenta • Inner cell mass is the source of human embryonic stem cells (hESCs) • hESCs have the ability to undergo differentiation • Maturation process in which cells develop specialized functions • Eventually can differentiate to form all of the more than 200 cell types in the human body hESCs - human embryonic stem cells

32. The blastocyst is a structure formed in the early embryogenesis, after the formation of the morula.

33. What are stem cells? • Source of hESCs • Embryos left over from IVF • Embryos created by IVF from sperm and egg cells donated for the purpose of providing embryos for research materials • hESCs can self-renew indefinitely to produce more stem cells • Create cell lines

34. Can adult stem cells do everything embryonic stem cells can do? • Cells of matured adult tissue can also be cultured and differentiated to produce other cell types • Small in number and not yet discovered in all adult tissues • Can differentiate into another different specialized cell type, but may not be as good as hESCs

35. Potential Applications of Stem Cells • Using stem cells to make white blood cells is becoming an effective way to treat leukemia • Stem cells from umbilical cord blood used to treat sickle cell anemia and other blood deficiencies • Stem cells from fat have been used to form bone tissue in the human skull • Repair of heart cells • Adult stem cells isolated from brain and used to make neurons in culture

36. What Is Sickle Cell Anemia? • Sickle cell anemia (uh-NEE-me-uh) is the most common form of sickle cell disease (SCD). SCD is a serious disorder in which the body makes sickle-shaped red blood cells. “Sickle-shaped” means that the red blood cells are shaped like a crescent.

38. 3. Gene Therapy • Gene therapy is the delivery of therapeutic genes into the human body to correct disease conditions created by a faulty gene or genes • How are genes delivered? • How can genes be sent to the proper tissues and organs? • Can it be effective and safe?

39. Different Delivery Systems are Available • In vivo versus ex vivo • In vivo = delivery of genes takes place in the body • Ex vivo = delivery takes place out of the body, and then cells are placed back into the body

40. 11.3 Gene Therapy • How is it done? • Two primary strategies • Ex vivo gene therapy • Cells are removed from the patient, treated with techniques similar to transformation, and then reintroduced to the person • In vivo gene therapy • Introducing genes directly into tissues and organs in the body • Challenge is delivering genes only to intended tissues and not tissues throughout the body

41. 11.3 Gene Therapy

42. 11.3 Gene Therapy • Vectors for Gene Delivery • Rely on viruses as vectors • Use viral genome to carry a therapeutic gene or genes and use virus itself to infect human cells, introducing the gene • Adenovirus (common cold) • Influenza virus (flu) • Herpes virus (cold sores, some cause STD) • Must make sure the virus has been genetically engineered so that it can neither produce disease nor spread throughout the body

43. 11.3 Gene Therapy • Viral Infection of Human Cells • Bind to and enter cells; release genetic material (usually DNA) into nucleus or cytoplasm • Human cell now acts as a host to reproduce the viral genome and to produce viral RNA and proteins • Make Good Vectors • Efficient at infecting many types of human cells • Retroviruses (HIV) permanently insert their DNA into host cell genome • Some viruses infect only certain types of cells – good for targeted gene therapy

44. 11.3 Gene Therapy • Other Gene Delivery Options • Naked DNA – DNA by itself that is injected directly into body tissues • Liposomes – small, hollow particles made of lipid molecules • Packaged with gene and injected or sprayed into tissues

45. 11.3 Gene Therapy • Antisense RNA Technology • A way to block translation of mRNA molecules to silence gene expression • Called RNA or gene silencing • Promising way to turn off disease genes • Used successfully in cell culture, but has yet to live up to its promise as a treatment for disease

46. 11.3 Gene Therapy • RNA interference (RNAi) • Double-stranded RNA molecules are delivered into cells where the enzyme Dicer chops them into 21-nt-long pieces called small interfering RNAs (siRNAs) • siRNAs join with an enzyme complex called the RNA-induced silencing complex (RISC) • RISC shuttles the siRNAs to their target mRNA where they bind • siRNA-bound mRNAs are degraded so they cannot be translated into a protein

47. 11.3 Gene Therapy

48. 11.3 Gene Therapy • First human gene therapy – SCID patient in 1990 • SCID is severe combined immunodeficiency • Defect in gene called adenosine deaminase (ADA) • Produces an enzyme involved in the metabolism of nucleotide dATP • Accumulation of dATP is toxic to T cells • Without T cells, B cells cannot recognize antigen and make antibodies • Ex vivo gene therapy successful

49. 11.3 Gene Therapy • Cystic Fibrosis – two defective copies of a gene encoding a protein called cystic fibrosis transmembrane conductance regulator (CFTR) • Normal protein serves as a pump to remove chloride ions from cell • Produced by many cells in the body – skin, pancreas, liver, digestive tract, male reproductive tract, and respiratory tract • Extremely thick sticky mucus in airways; infertility; extremely salty sweat

50. 11.3 Gene Therapy