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Questions and Answers
ما هو تخصص الدكتور أحمد دغيدي؟
ما هو تخصص الدكتور أحمد دغيدي؟
أي جامعة ينتمي إليها الدكتور أحمد دغيدي؟
أي جامعة ينتمي إليها الدكتور أحمد دغيدي؟
ما هو رقم المحاضرة المذكور في المحتوى؟
ما هو رقم المحاضرة المذكور في المحتوى؟
ما هو المجال الأكاديمي للدكتور أحمد دغيدي؟
ما هو المجال الأكاديمي للدكتور أحمد دغيدي؟
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من أين حصل الدكتور أحمد دغيدي على درجة الدكتوراه؟
من أين حصل الدكتور أحمد دغيدي على درجة الدكتوراه؟
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ما هي الوظيفة الرئيسية لكل من Sox2 و Oct4 في الخلايا الجذعية؟
ما هي الوظيفة الرئيسية لكل من Sox2 و Oct4 في الخلايا الجذعية؟
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أي من المعلومات التالية صحيحة بخصوص Sox2 و Oct4؟
أي من المعلومات التالية صحيحة بخصوص Sox2 و Oct4؟
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ما هي نتيجة تنشيط Sox2 و Oct4 في الخلايا الجذعية؟
ما هي نتيجة تنشيط Sox2 و Oct4 في الخلايا الجذعية؟
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أي من العوامل التالية تعزز قدرة Sox2 و Oct4 على الحفاظ على pluripotency؟
أي من العوامل التالية تعزز قدرة Sox2 و Oct4 على الحفاظ على pluripotency؟
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كيف تسهم Sox2 و Oct4 في عملية نشوء الخلايا الجذعية؟
كيف تسهم Sox2 و Oct4 في عملية نشوء الخلايا الجذعية؟
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Study Notes
Induced Pluripotent Stem Cells (iPSCs)
- iPSCs are artificially derived pluripotent stem cells from non-pluripotent cells (typically adult somatic cells).
- They are created by inducing the expression of specific genes.
- First produced in 2006 from mouse cells and in 2007 from human cells.
Methods of Reprogramming Somatic Cells to iPSCs
- Somatic Cell Nuclear Transfer (SCNT): Involves transferring the nucleus of a somatic cell into an enucleated egg cell.
- Cell Fusion: Two cells are fused to combine their genetic material.
- Treatment with Pluripotent Stem Cell Extract: Using a substance from pluripotent stem cells.
- Stable Expression of Defined Factors: Achieving a stable expression of specific genes.
iPSCs Production Details
- Typically derived by transfecting specific stem cell-associated genes into non-pluripotent cells, like adult fibroblasts.
- Transfection is commonly performed using viral vectors (like retroviruses).
- After 3-4 weeks, some transfected cells morph and become chemically similar to pluripotent stem cells.
- Isolation can be achieved through morphological selection, doubling time, reporter genes, or antibiotic selection.
First Generation of iPSCs (2006)
- Developed by Shinya Yamanaka's team at Kyoto University.
- Used four key pluripotency genes: Oct-3/4, Sox2, c-Myc, and Klf4.
- Retroviruses were used to introduce the genes into mouse fibroblasts.
- Isolated cells by antibiotic selection using Fbx15.
Second Generation of iPSCs (2007)
- Developed by the same team.
- Used the same four key pluripotency genes but instead of Fbx15 used Nanog .
- DNA methylation patterns and viable chimeras demonstrated Nanog as a major determinant of cellular pluripotency.
Limitations of iPSC Production
- One of the four genes used (c-Myc) has oncogenic potential.
- 20% of chimeric mice developed cancer.
- In a later study, it was possible to create iPSCs without c-Myc, although the process was less efficient and the resulting chimeras did not develop cancer.
Human iPSCs (2007)
- Created using similar methodology to mouse models using four same crucial genes.
- Human fibroblasts were transformed into pluripotent stem cells.
- A retroviral system was employed for introducing these genes.
Applications of iPSCs
- Disease Modeling: Studying disease mechanisms in vitro using patient-specific iPSCs.
- Drug Screening: Testing drug efficacy and toxicity on patient-specific iPSC-derived cells.
- Toxicological Testing: Evaluating the toxicity of new drugs and chemicals.
- Regenerative Medicine: Creating tissues and organs for transplantation.
- Stem Cell Therapy: Treating various diseases, including Parkinson's disease, sickle cell anemia, heart disease, rheumatoid arthritis and Type 1 diabetes. Using iPSCs to generate specific cells for treatment which may circumvent ethical concerns and transplant rejection.
- Mouse Kidney Creation: Creating mouse kidneys utilising iPSCs.
- Tissue Repair: Regenerating damaged tissues, such as the spinal cord and cardiac tissue.
Conclusion
- SCNT and cell fusion methods can generate pluripotent cells, but practically these are mostly used in animal models only.
- iPSC technology holds significant promise for addressing ethical concerns and transplant rejection issues.
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Description
الخلايا الجذعية متعددة القدرات المستحثة (iPSCs) تُشتق من خلايا جسمية غير متعددة القدرات. يتم إنتاجها من خلال طرق مثل نقل النواة أو اندماج الخلايا. اكتُشفت لأول مرة في عام 2006 من خلايا الفأر وفي عام 2007 من خلايا الإنسان.
