Development of genetic therapy: world achievements

Development of genetic therapy: world achievements

I. Fundamentals of gene therapy: from concept to practice

1. Historical roots and early experiments:

   • The concept of genetic therapy, originated in the middle of the 20th century, was based on the idea of the possibility of correcting genetic defects by introducing a healthy copy of the gene into the cells of the body.
   • Early attempts by genetic therapy made in the 1970s and 1980s were limited by technological capabilities and understanding of biological processes.
   • The first officially approved clinical protocol of genetic therapy was implemented in 1990 in a girl suffering from adenosinezamine deficiency (ADA-Scid). This experience, although not without problems, has become an important step in the development of the region.
   • Failures in the early clinical trials associated with the inefficiency of vectors and the occurrence of undesirable side effects led to the revision of approaches and the intensification of research in the development of safer and more effective technologies.

2. Key concepts and terminology:

   • Gene therapy: the method of treatment of diseases based on the introduction of genetic material into the cells of the body in order to restore or modify their function.
   • Gene: DNA section containing information necessary for the synthesis of a certain protein.
   • Vector: a means of delivery of genetic material to cells. Viral vectors (adenoviruses, retroviruses, adenoassed viruses) and non -viral vectors (liposomes, plasmids) are used for this purpose.
   • Transication: the process of introducing genetic material into cells.
   • Transduction: the process of introducing genetic material into cells using viral vectors.
   • Gene expression: the process of protein synthesis based on information contained in the gene.
   • In vivo gene therapy: the introduction of a vector with a therapeutic genome directly into the patient’s body.
   • EX Vivo Gene therapy: Genetic modification of the patient’s cells outside the body, followed by transplantation of these cells back to the patient.
   • Directed genetic therapy: delivery of the therapeutic gene to certain tissues or target cells.
   • Genoma editing: the use of technologies such as CRISPR-CAS9 for accurately changing the sequence of DNA in the cells.

3. Types of genetic therapy:

   • General replacement therapy: The introduction of a functional copy of the gene to compensate for the deficit or lack of its own gene. It is used for monogenic diseases, such as cystic fibrosis or hemophilia.
   • Inhibitor gene therapy: The introduction of a genetic material that blocks the expression of an undesirable gene. It is used in the treatment of infectious diseases, oncological diseases and some hereditary diseases.
   • Gene therapy with an immunomodulating effect: The introduction of genes stimulating or suppressing the body’s immune response. It is used in the treatment of autoimmune diseases, oncological diseases and infectious diseases.
   • Genoma editing: The use of technologies, such as CRISPR-CAS9, for accurately changing the DNA sequence in cells. Open opportunities for correcting genetic defects and treating a wide range of diseases.

II. Vectors for genetic therapy: evolution and current state

1. Viral vectors:

   • Adenoviruses: They have high efficiency of transduction, but can cause an immune response. Used to treat cancer and vaccination.
   • Adenoassed viruses (AAV): Have low immunogenicity and the ability to prolonged expression of the gene. They are widely used in genetic therapy of hereditary diseases, such as spinal muscle atrophy (SMA) and LEBRAM AMAVROZ.
   • Retrovirus: Capable of integration in the genome of the host cell, which ensures prolonged expression of the gene. However, integration can occur in random places of the genome, which can lead to undesirable side effects. Used for genetic therapy of hematological diseases and oncological diseases.
   • Lentviruses: The subclass of retroviruses capable of transduciting both dividing and weekly cells. They are used for genetic therapy of a wide range of diseases, including HIV infection and hereditary diseases.
   • Herpes virus: They have a large container for genetic material and the ability to infect nerve cells. Used for genetic therapy of neurological diseases and oncological diseases.

2. Nevirus vectors:

   • Liposomes: Artificial lipid bubbles used to deliver DNA to cells. They have low toxicity and immunogenicity, but less effective than viral vectors.
   • Plasmids: Ring DNA molecules used to deliver genes to cells. They have low toxicity and simplicity of production, but less effective than viral vectors.
   • Electropolitan: The method of introducing DNA into the cells using an electric field.
   • Gene’s gun: The method of introducing DNA into cells using microscopic particles of gold coated with DNA.
   • Conjugates of polymers with DNA: The use of polymers to protect DNA from degradation and improve its delivery to cells.

3. Modern trends in the development of vectors:

   • Targeted vectors: Development of vectors that can selectively deliver genetic material to certain tissues or target cells. This allows you to reduce the risk of side effects and increase the effectiveness of gene therapy.
   • Improved viral vectors: Modification of viral vectors to reduce their immunogenicity and increase the efficiency of transduction.
   • Development of new non -viral vectors: Creation of non -viral vectors with improved characteristics of the delivery and expression of the gene.
   • Using nanotechnologies: The use of nanoparticles for the delivery of genetic material to cells.

III. The use of genetic therapy in the treatment of hereditary diseases

1. Spinal muscle atrophy (SMA):

   • SMA is a genetic disease characterized by progressive muscle weakness and atrophy caused by a mutation in the SMN1 gene.
   • Genetic SMA therapy using the AAV vector, delivering a functional copy of the SMN1 gene, is one of the most successful examples of genetic therapy.
   • The drug Zolgensma (OnaseMnogene Abeparvovec) is approved for the treatment of SMA in children under two years of age and demonstrates high efficiency in improving motor functions and survival.

2. LEBRAM AMAVROZ:

   • Leber Amaurosis is a group of hereditary diseases of the retina leading to progressive loss of vision.
   • Genetical therapy of Leber Amaurosis, caused by a mutation in the RPE65 gene, using the AAV vector, delivering a functional copy of the RPE65 gene, demonstrated a significant improvement in vision in patients.
   • The drug Luxturna (Voretigene Neparvovec) is approved for the treatment of Leber Amavrosis and is the first genetotherapeutic drug approved for the treatment of a hereditary eye disease.

3. Hemophilia:

   • Hemophilia is a group of hereditary diseases characterized by a violation of blood coagulation caused by a deficiency of blood coagulation factors.
   • Genetical therapy of hemophilia using AAV vehicles delivering blood coagulation factors showed encouraging results in a decrease in the frequency of bleeding and improving the quality of life of patients.
   • Several genetotherapeutic drugs for the treatment of hemophilia undergoes clinical trials and demonstrate the potential to ensure a long -term remission of the disease.

4. MukoviScidoz:

   • Cycocidosis is a genetic disease characterized by a violation of the function of exocrine glands, leading to damage to the lungs, pancreas and other organs.
   • Gene therapy of cystic fibrosis is aimed at delivering the functional copy of the CFTR gene to the lung cells to restore the normal function of chloride channels.
   • Various approaches to genetic therapy of cystic fibrosis are developed, including the use of viral and non-viral vectors, as well as MRNA therapy.

5. Beta-Talassemia:

   • Beta-Talassemia is a hereditary blood disease characterized by a decrease or lack of synthesis of beta-globin, a hemoglobin component.
   • Gene therapy of beta-thalassemia includes the modification of hematopoietic stem cells of the patient EX Vivo using levvirus vector, delivering a functional copy of the beta-globin gene.
   • The drug Zynteglo (Betibeglogene Autotemcel) is approved for the treatment of beta-Talassemia and allows patients to abandon regular blood transfusion.

IV. Genetic therapy in oncology: new horizons of the fight against cancer

1. Oncolytic viruses:

   • Oncolytic viruses are genetically modified viruses that selectively infect and destroy cancer cells without damaging healthy cells.
   • Oncolytic viruses can cause the lysis of cancer cells, stimulate the immune response against cancer and deliver therapeutic genes to cancer cells.
   • Imlygic (Talimogene LaherparepVec) is an oncolytic virus approved for the treatment of melanoma.

2. Car-T-cell therapy:

   • CAR-T-cell therapy is a form of immunotherapy in which the patient’s T-lymphocytes are modified by EX Vivo for the expression of a chimeric antigenic receptor (CAR), which recognizes specific antigens on the surface of cancer cells.
   • Car-T cells are then introduced back to the patient, where they attack and destroy cancer cells.
   • Several Car-T cell drugs are approved for the treatment of lymphomas and leukemia.

3. Gene therapy with an immunomodulating effect:

   • Genetic therapy with an immunomodulating effect is aimed at stimulating an immune response against cancer by introducing genes encoding cytokines, trembleing molecules or cancer antigens.
   • This therapy can strengthen the ability of the immune system to recognize and destroy cancer cells.

4. Gene therapy to increase sensitivity to chemotherapy and radiation therapy:

   • Gene therapy can be used to increase the sensitivity of cancer cells to chemotherapy and radiation therapy by introducing genes that block the mechanisms of resistance to these treatment methods.

5. Gene therapy to prevent metastasis:

   • Gene therapy can be used to prevent cancer metastasis by introducing genes that block the processes involved in metastasis, such as cell adhesion, migration and angiogenesis.

V. General therapy in the treatment of infectious diseases

1. HIV infection:

   • Gene therapy of HIV infection is aimed at suppressing the replication of the virus, protecting cells from infection and stimulating an immune response against HIV.
   • Different approaches to genetic therapy of HIV infection include the use of antislay oligonucleotides, ribosims, dominant negative mutants and car-t cells specific to HIV.
   • Studies in the field of genetic therapy of HIV infection are aimed at achieving a functional cure, in which the virus is under control without the need for constant antiretroviral therapy.

2. Hepatitis B and C:

   • Genetic hepatitis B and C is aimed at suppressing the replication of the virus, stimulating the immune response against the virus and protecting the liver from damage.
   • Various approaches to genetic hepatitis B and C include the use of RNA interference, CRISPR-CAS9 and immunomodulating genes.

3. Other viral infections:

   • Gene therapy is developed for the treatment of other viral infections, such as flu, coronavirus infection and Ebola virus.
   • These approaches include the use of antivirus genes, immunomodulating genes and vaccines based on genetic material.

4. Bacterial infections:

   • Gene therapy can be used to treat bacterial infections by introducing genes encoding antimicrobial peptides or antibodies specific to bacteria.
   • The approaches to genetic therapy are also developed, aimed at increasing the immune response against bacteria.

VI. Genoma editing: CRISPR-CAS9 and other technologies

1. CRISPR-CAS9: The mechanism of action and application:

   • CRISPR-CAS9 is a genome editing technology based on the use of the CAS9 enzyme and the RNA guide (GRNA) for accurately changing the DNA sequence in the cells.
   • CAS9 is nuclease that cuts DNA in a place determined by GRNA.
   • After cutting the DNA, the cell tries to restore the gap using either a non -humorous compound of the ends (NHEJ), which can lead to mutations, or homologous recombination (HDR), which allows you to insert new genetic material.
   • CRISPR-CAS9 is used to correct genetic defects, shutdown genes, introduce new genes and create cellular models of diseases.

2. Other genome editing technologies: Talens, ZFNS:

   • Talens (transcription activator-like effector nucleases) and ZFNS (zinc fingers of nuclease) are other genome editing technologies based on the use of proteins binding to DNA to deliver nuclease to certain genome areas.
   • Talens and ZFNS have high specificity, but their development and production are more complex than CRISPR-CAS9.

3. Clinical testing of genome editing:

   • Clinical testing of the genome editing for the treatment of various diseases, including beta-talassemia, sickle cell anemia, HIV infection and oncological diseases are carried out.
   • The first results of the clinical testing of genome editing demonstrate the encouraging potential of this technology for the treatment of incurable diseases.

4. Ethical and regulatory aspects of the genome editing:

   • The genome editing serious ethical and regulatory issues related to safety, efficiency and justice of access to this technology.
   • Of particular concern is editing the genome of the germline, which can lead to transmission of genetic changes to offspring.
   • Strict ethical and regulatory frames are needed to ensure the responsible use of genome editing technology.

VII. Actual achievements and prospects of genetic therapy in the world

1. Approved genetotherapeutic drugs:

   • Zolgensma (OnaseMnogene Abeparvovec) for the treatment of spinal muscle atrophy (SMA).
   • Luxturna (Voretigene Neparvovec) for the treatment of LEBER amaurosis.
   • Zynteglo (Betibeglogene Autotemcel) for the treatment of beta-Talassemia.
   • Glybera (Alipogene Tiparvovec) for the treatment of lipoproteinlipase deficiency (LPLD) (currently withdrawn from the market).
   • Imlygic (Talimogene LaherparepVec) for the treatment of melanoma.
   • Kymriah (TisagenleCleucel) and Yescarta (Axicabtagene Ciloleucel) for the treatment of lymphomas.

2. Clinical trials of genetic therapy:

   • Numerous clinical trials of genetic therapy are carried out for the treatment of a wide range of diseases, including hereditary diseases, oncological diseases, infectious diseases and neurological diseases.
   • These tests are aimed at assessing safety, efficiency and long -term genetic therapy results.

3. New areas of research in genetic therapy:

   • Development of new vectors with improved characteristics of the delivery and expression of the gene.
   • The development of technologies of directed genetic therapy for the selective delivery of genetic material to certain tissues or target cells.
   • The use of nanotechnologies to deliver genetic material to cells.
   • Development of genetic therapy for the treatment of complex diseases, such as Alzheimer’s disease and diabetes.
   • The use of genome editing to correct genetic defects and create new treatment methods.

4. Problems and challenges in the development of genetic therapy:

   • High cost of genetotherapeutic drugs.
   • Limited accessibility of genetic therapy.
   • Potential side effects of genetic therapy, such as an immune response and outside the target editing of the genome.
   • Ethical