Lecture 21 - Stem Cell Therapy for Hereditary Diseases

Question 1

What are the three classes of stem cells?

Answer 1

1. ES cells 2. iPS cells 3. tissue-specific cells *Note: “transit amplifying cells” (TA cells also are featured as treatment.

Question 2

What is the distinguishing feature of the cells on the far left and at the top of the image?

Answer 2

iPS cells and ES cells can divide indefinitely, a property known as self renewal.

Question 3

_____________ stem cells can also self-renew, but have a more limited differentiation potential than ES or iPS cells.

Answer 3

Tissue-specific stem cells

Question 4

The property of “self-renewal” in embryonic stem cells and induced pluripotent stem cells reflects what two features of these cells?

Answer 4

1. Expression of specific genes (cell-intrinsic molecules, such as transcription factors)
2. Cell location in “stem cell niches” - restricted regions that contain extrinsic molecules required to maintain stem cells

Question 5

What are “stem cell niches”?

Answer 5

Restricted regions that contain extrinsic molecules required to maintain stem cells.

Question 6

Tissue-specific stem cells are present in _______ as well as many adult tissues, where they contribute to continuous replacement of cells.

Answer 6

embryos

Question 7

_________ cells can divide a limited number of times and can produce only one or a few types of cells in any specific tissue.

Answer 7

Transit amplifying precursor cells

Question 8

_____ cells have stopped dividing, or have a very limited capacity to divide.

Answer 8

Somatic cells

Question 9

Somatic cells have a very limited capacity to divide unless they are manipulated by ___(a)___ or ___(b)___ to become ____(c)___ cells?

Answer 9

a) gene transfer
b) environmental factors
c) iPS cells

Question 10

Both intrinsic and extrinsic molecules critical for the maintenance of different types of stem cells has been achieved using what two important approaches?

Answer 10

1. Gene expression profiling - comparing stem cells to more differentiated cells
2. Gain or loss of function assays in vitro

Question 11

How is “gene expression profiling” defined?

Answer 11

Comparing stem cells to more differentiated cells

Question 12

Gene expression profiling and gain-of-function/loss-of-function assays are techniques that have provided critical information regarding the mechanism of generating ______ cells.

Answer 12

iPS (induced pluripotent) stem cells

Question 13

Introducing a small number of genes (i.e. Oct4/Sox2/lin-28/Klf4) to derive iPS cells from somatic cells of embryos or adults is a process known as ____________.

Answer 13

reprogramming

Question 14

Cells that had become restricted to divide a limited number of times and generate just one type of cell can acquire many of the properties of ______ cells via the process of reprogramming.

Answer 14

ES cells

Question 15

Although ES and iPS cells are pluripotent, different lines of ES/iPS cells derived from specific types of ___________ cells may exhibit hiases in their tendency to generate specific types of cells.

Answer 15

somatic cells

Question 16

What are 3 general ways stem cells can be manipulated before they are transplanted?

Answer 16

1. Cell sorting (via expression of cell-surface markers)
2. In-vitro propagation (used with iPS, ES, and tissue-specific cells)
3. Gene-specific targeting (i.e. CRISPR technology)

Question 17

An example of gene-specific targeting that makes genome editing in human cells more feasible is ________.

Answer 17

CRISPR technology

Question 18

Neural stem cells from the human CNS have the ______ phenotype, allowing them to be used with a panel of antibodies and cell sorting (i.e. flow cytometry or FACS) to be selected from a heterogenous cell mixture.

Answer 18

antigenic phenotype

Question 19

An alternative to stem cells is ________, also called transdifferentiation.

Answer 19

direct lineage conversion

Question 20

What does direct lineage conversion accomplish?

Answer 20

conversion of one type of somatic cell into another type of somatic cell

Question 21

With the transdifferentiation approach, a fibroblast can be turned into a neuron using a combination of __________ without going through a stem cell intermediate.

Answer 21

transcription factors

Question 22

What are the two advantages of direct lineage conversion (“transdifferentiation”)?

Answer 22

1. Faster than reprograming
2. Cells can maintain features of “adult” stages

Question 23

What is the main disadvantage of direct lineage conversion (“transdifferentiation”)?

Answer 23

the number of appropriate cells generated is limited

Question 24

What mode of inheritance is the hereditary disease “infantile neuronal ceroid lipofuscinosis” (INCL)?

Answer 24

autosomal recessive (mutation in CLN1 gene, which encodes PPT1 enzyme)

Question 25

Advantages of using neural stem cells (there are four listed in syllabus!) include that they:

Answer 25

1. migrated extensively from sites of injection 2. differentiate in a region appropriate manner 3. integrate into the host tissue 4. did not form tumors

Question 26

Disadvantages of using neural stem cells is that they are:

Answer 26

1. obtained from human embryos 2. not matched immunologically to the patient (possibility)

Question 27

Which type of cells would eliminate the histocompatibility problem of using neural stem cells in stem cell transplantation therapy for clinical trials of INCL?

Answer 27

use of **iPS cells** would have eliminated the histocompatability problem \*Note: if **ES cells** had been used instead, histocompatability would have still been an issue (embryonic stem cells can have unique immunological features)

Question 29

Huntington's disease is a late-onset, autosomal dominant neurological disease associated with loss of ______ in the \_\_\_\_\_\_.

Answer 29

loss of **medium spiny neurons (MSNs)** in the **striatum**

Question 30

One alternative to human fetal tissue is ________ cells induced to differentiate into the precursors of MSNs.

Answer 30

human ES (hES)

Question 31

hES cells would requrie immune suppression when induced to differentiate into the precursors of MSNs. ________ would not.

Answer 31

iPS cells

Question 32

Order the following cells from MOST proliferation and differentiation potential to LEAST: A. iPS cell B. Somatic cell C. Tissue-specific stem cell D. Transit amplifying cell

Answer 32

A\>C\>D\>B

Question 33

The best type of cell for transplantation therapy to treat sickle cell disease is:

Answer 33

**Hematopoietic stem cells** derived from the **sickle cell disease patient's iPS cells** that have been **genome-edited** to correct the beta-globin mutation.

Question 34

Induced pluripotent cells are the product of: A. Germ cell proliferation B. Embryonic cell differentiation C. Somatic cell reprogramming D. Stem cell division

Answer 34

C.

Question 35

Transit-amplifying cells are the product of: A. Germ cell proliferation B. Embryonic cell differentiation C. Somatic cell reprogramming D. Tissue-specific stem cell division

Answer 35

D.