Lecture 23 Review

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which type of stem cells are capable of becoming any cell type including the placenta?

Multipotent Stem Cells

Oligopotent Cells

Totipotent Cells (correct)

Pluripotent Stem Cells

What distinguishes multipotent stem cells from pluripotent stem cells?

Multipotent stem cells can become any cell type.

Pluripotent stem cells only differentiate into adult tissues.

Multipotent stem cells give rise to a limited set of cells. (correct)

Pluripotent stem cells are more limited in the types they can become.

Which of the following stem cells is considered a type of adult stem cell?

Totipotent Stem Cells

Induced Pluripotent Stem Cells

Hematopoietic Stem Cells (correct)

Embryonic Stem Cells

Induced Pluripotent Stem Cells (iPSCs) are derived from which source?

Adult somatic cells Signup and view all the answers

What term describes stem cells that are already committed to a specific lineage but are not yet terminally differentiated?

Oligopotent Cells Signup and view all the answers

What is a significant technical problem associated with therapeutic cloning?

Low success rate of nucleus transplantation Signup and view all the answers

Which of the following is NOT an ethical concern regarding therapeutic cloning?

Potential loss of genetic diversity Signup and view all the answers

Who was awarded the Nobel Prize in Physiology or Medicine in 2012 for the discovery of reprogramming mature cells to become pluripotent?

Shinya Yamanaka Signup and view all the answers

What are OSK transcription regulators necessary for?

Maintaining pluripotency in stem cells Signup and view all the answers

Which characteristic differentiates iPS cells from embryonic stem cells?

iPS cells are created from somatic cells, while ES cells are derived from embryos Signup and view all the answers

What must be done to the pluripotency factors in iPS cells for them to effectively differentiate?

They must be turned off Signup and view all the answers

What is one of the outcomes of the expression of ~1500 genes in response to pluripotency regulators?

Increased ability to differentiate into all cell types Signup and view all the answers

Which transcription factor is NOT part of the OSK group necessary for pluripotency?

Cdx2 Signup and view all the answers

What is a potential risk associated with using somatic cells to create iPS cells?

Damaging mutations Signup and view all the answers

What type of stem cells are commonly used in clinical settings for cancer treatment?

Adult hematopoietic stem cells Signup and view all the answers

What significant discovery related to mouse genetics resulted in a Nobel Prize in Physiology/Medicine in 2007?

Gene targeting using embryonic stem cells Signup and view all the answers

What role does leptin play in the body, as demonstrated by the leptin knockout experiment?

Regulates body fat and hunger sensation Signup and view all the answers

What technique involves using CRISPR/Cas9 with embryonic stem cells?

Gene knockout Signup and view all the answers

What is a challenge associated with the safety of reprogramming cells into iPS cells?

Uncertain effects of mutations Signup and view all the answers

Which process is involved in transplanting adult hematopoietic stem cells into a patient?

Chemotherapy or radiation Signup and view all the answers

How do cultivated ES or iPS cells contribute to organoid development?

By giving rise to a three-dimensional structure Signup and view all the answers

What is a primary characteristic of stem cells?

They can create both more stem cells and differentiated progeny. Signup and view all the answers

Which of the following accurately distinguishes embryonic stem cells from adult stem cells?

Embryonic stem cells can differentiate into cell types of all three germ layers, while adult stem cells are limited. Signup and view all the answers

What is the concept of the 'stem cell niche'?

An environment that supports and regulates stem cell behavior. Signup and view all the answers

What challenge is commonly associated with the use of adult stem cells in therapy?

They are often found in insufficient quantities. Signup and view all the answers

How can induced pluripotent stem cells (iPS cells) be generated?

By reprogramming differentiated cells into a pluripotent state. Signup and view all the answers

What potential utility of organoids is recognized in biomedical research?

They can be used for drug testing and disease modeling. Signup and view all the answers

Which of the following is a basic scientific promise of stem cell biology?

Control embryonic development. Signup and view all the answers

Which of the following diseases might benefit from stem cell therapy?

Diabetes Signup and view all the answers

What is the role of the stem cell niche?

It produces signals that regulate stem cell proliferation and differentiation. Signup and view all the answers

What is a primary challenge associated with the use of adult stem cells in therapy?

Their niche conditions are difficult to identify. Signup and view all the answers

Which of the following statements accurately describes embryonic stem cells?

They are pluripotent and can give rise to any cell type under appropriate conditions. Signup and view all the answers

What ethical concern is associated with the use of embryonic stem cells?

The creation of blastocysts solely for stem cell extraction. Signup and view all the answers

Why are adult stem cells considered challenging for therapy?

They show weak growth in culture and have limited expansion capability. Signup and view all the answers

What is a characteristic feature of the inner cell mass (ICM) in a blastocyst stage mammalian embryo?

It gives rise to all cells in the body (pluripotent). Signup and view all the answers

What is a common technical problem associated with embryonic stem cells?

The differentiation pathways are not well defined. Signup and view all the answers

Which statement about the scarcity of adult stem cells is true?

They account for roughly 1 in every 1000 cells in the body. Signup and view all the answers

Study Notes

Stem Cells

Stem cells are capable of self-renewal, creating more stem cells and differentiated progeny.
Stem cells demonstrate differences between embryonic and adult stem cells.
The stem cell niche is the environment that produces signals to regulate stem cell proliferation and differentiation.
Using adult stem cells or embryonic stem cells in therapy presents challenges.
Induced pluripotent stem cells (iPS cells) can be generated.
Organoids in biomedical research can be useful tools.

Learning Objectives

Understanding stem cells' capacity for self-renewal and differentiation.
Differentiating between embryonic and adult stem cells.
Understanding the stem cell niche concept.
Recognizing challenges of using stem cells in therapy.
Understanding induced pluripotent stem cell generation.
Recognizing organoids' potential as biomedical tools.

BIOMG1350 Course Information

Prelim 4: December 9, 2024 (sections L19-24, S10-11). Room assignments available by Saturday, practice prelim will be uploaded, review sessions with TAs are scheduled (1-4 PM Saturday/Sunday in G01 Biotech).
Final Exam: Saturday, December 14, 2024, 9:00 AM, at Barton Hall (BTN100CENT, BTN100EAST). Practice prelims may be available for review. Review sessions with TAs scheduled (1-3 PM) December 12th (Thursday) in Racker room G01 and December 13th (tentatively Warren Hall 101). Make-up exam requests due Wednesday, Dec 4th.

Quotes, Quotes, Quotes

Quote by Alan Spradling (2001): People are fascinated with stem cells due to the potential of perpetual motion machines and the fountain of youth. Understanding stem cells could help realize their mythic promise. (Nature 414:98).

Stem Cell Excitement

Basic science promise: The promises of stem cell biology include tissue homeostasis, controlling embryonic development, and regeneration, as well as dealing with aging.
Clinical applications promise: Diabetes, cardiovascular diseases, Parkinson's, Alzheimer's, severe burns, spinal cord injuries, and more.

Stem Cell Definition

Stem cell: A cell with a high capacity for self-renewal, creating more stem cells and differentiated progeny (offspring).

Types of Stem Cells

Totipotent Cells: Makes all embryo cells and placenta.
Pluripotent Stem Cells: Embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs).
Adult/Tissue Stem cells: Hematopoietic stem cells (HSCs), epidermal stem cells (EpSCs), Neural stem cells (NSCs)
Multipotent Stem Cells: a type of stem cell with the ability to differentiate into a limited number of related cell types.

Adult Stem Cells

Committed stem cells.
Give rise to limited sets of cells and tissue types (multipotent).
Examples include hematopoietic, epidermal, neural, hair, and melanocytes.
Present throughout the life of the individual.
Rare, difficult to isolate (approximately 1/1000 cells).

Stem Cell Niche

Regulatory environment for adult stem cells.
Produces signals that regulate stem cell proliferation and differentiation.
Factors include niche cells, adhesive molecules, extracellular matrix (ECM) and basement membrane.

Stem Cell Niche in the Mammalian Intestine – Specialized environments

Location of stem cells within the small intestine.
Processes of stem cell proliferation and differentiation, including location in the crypt and the passage to the villus

Challenges Using Adult Stem Cells in Therapy

Scarcity of adult stem cells to isolate.
Need different kinds of adult stem cells for different treatments.
Identifying the niche conditions necessary to maintain and differentiate adult stem cells.
Adult stem cells grow poorly in culture and are difficult to expand.

Embryonic Stem (ES) Cells

Derived from cells in embryogenesis.
Can be cultured and maintained in a undifferentiated state.
Can differentiate into any cell type in the body under appropriate conditions.
Derived from a blastocyst (a pre-embryo stage).
Inner cell mass (ICM) and trophoblast are parts of the blastocyst
ICM gives rise to all cells of the developing embryo. Trophoblast gives rise to extra-embryonic tissues (like the placenta).

ES Cell Therapeutic Potential

ES cells have remarkable therapeutic potential, despite obstacles.

Problems Associated with ES Cells in Therapy

Technical problems:
- Histo-incompatibility (patient rejection).
- Unsure pathways to follow in differentiation.
Ethical problems:
- Morality of creating human blastocysts for research. -Blastocyst status as a human individual

Induced Pluripotent Stem (iPS) Cells

Mature cells, reprogrammed to become pluripotent.
Nobel Prize in Physiology or Medicine (2012).
Significant technique for producing iPS cells is culturing fibroblasts (skin) and introducing key transcription regulators (e.g. Oct4, Sox2, Klf4, c-Myc).

iPS Cell Uses

Used in various research, particularly in genetic diseases.
Creating iPS cells from patients with genetic diseases allows cell-based models to screen potential therapies for the disease.

iPS Therapy Challenges:

Turning off pluripotency factors to permit differentiation to avoid tumorigenesis.
iPS cells are not the same, due to variations in epigenetic marks.
Stem cells can also have mutations.
Reprogramming safety isn't fully clear yet.
While seemingly straightforward, the process still has many challenges.

Nuclear Transfer Stem Cells (NTSCs)

"Therapeutic cloning" technique.
Uses cells from adult tissues and unfertilized eggs.
Involved processes like cell fusion or nuclear injection.
Results in personalized embryonic stem cells (ESCs).

Therapeutic Cloning Problems

Low success rates need many donated eggs.
Ethics surrounding human blastocyst creation.

Gene Knockout Experiments in Mice

Researchers use gene knockouts in mice to investigate the role of specific genes.
A gene knockout removes or disables a specific gene to see what happens without that gene.
In the example cited, removing a gene that controls leptin production leads to obesity.

Stem Cells and Cancer

Stem cells are potential cancer targets.
Long lifespan and high proliferative capacity can increase mutation potential leading to transformation.
Cancer stem cells are rare tumor cells and can rebuild a tumour.
Stem cell regulatory signals, including quiescence, activation, and differentiation signals usually play a role in cancer, although how that role manifests depends on the cancer type.

Stem Cell Renewal and Pro-Cancer Pathways

The processes for stem cell renewal are intertwined with pathways linked to cancer.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on the different types of stem cells, their characteristics, and ethical considerations in stem cell research. This quiz covers key concepts including pluripotent and multipotent stem cells, therapeutic cloning, and notable scientific discoveries in the field.