Cardiovascular Health 3.3 (Heart): New Frontiers in micro RNA therapies

Question 1

Are miRNAs associated with disease?

Answer 1

Yes.

Question 2

What are miRNAs?

Answer 2

Short RNA strands that arent involved in protein production.

Question 3

Where do miRNAs bind?

Answer 3

To the 3’ complementary region of mRNA, at the seed region.

Question 4

What is the effect of miRNA binding to mRNA?

Answer 4

Can cause mRNA degredation or protein synthesis inhibition.

Question 5

Can one miRNA target more than one mRNA?

Answer 5

Yes, hundreds.

Question 6

Can many miRNAs target the same mRNA?

Answer 6

Yes.

Question 7

What happens when the Dicer gene is deleted? Is there a cure?

Answer 7

Heart is enlarged in its absence, thin walls, poor blood pumping and premature death.
No cure, treatment slows progression.

Question 8

What happens when miRNAs are disregulated?

Answer 8

A disease.

Question 9

What is pathological hypertrophy?

Answer 9

Occurs when a diseased, such as high blood pressure. Increases fibrosis and apoptosis.

Question 10

What is physiological hypertrophy?

Answer 10

Is cardioprotective, with no apoptosis or fibrosis.

Associated with good heart function.

Question 11

Is PI3K cardioprotective?

Answer 11

Yes.

Question 12

What happens when PI3K is up/downregulated?

Answer 12

When subject to a heart disease, upregulated PI3K hearts were cardioprotected.
Downregulated hearts were more susceptible to pathology.

Question 13

What effects does PI3K have on heart pathology?

Answer 13

Prevents fibrosis, excessive heart growth, and heart dysfunction.

Question 14

How can a cardiovascular disease be treated via PI3K?

Answer 14

Associated miRNA needs to be found.

Question 15

How can the PI3K miRNA be found?

Answer 15

Obtain a spectrum of heart tissue, with varying heart pathology.
Use microarray to find miRNA.

Question 16

When using microarrays to find miRNA associated with PI3K, what must its levels be in healthy vs damaged heart tissue?

Answer 16

Low in healthy, but high in susceptible and damaged heart tissue.

Question 17

Once miRNAs are found, what must be done to treat the cardiovascular disease?

Answer 17

Block them using miRNA blockers.

Question 18

How can miRNA blocker effeciveness be evaluated?

Answer 18

Induce pressure overload heart failure.

Question 19

What happens to miRNA after delivering? Are they stable when delivered?

Answer 19

Turn into locked nucleic acids.

Stable, no need for vectors.

Question 20

Are miRNAs toxic?

Answer 20

No.

Question 21

What effect did miRNA blockers have?

Answer 21

Prevented heart growth and improved function and weight.

Question 22

How can luciferase be used for target validation?

Answer 22

A plasmid vector is used to carry the miRNA and target plasmid.
When they arent bound, luciferase activity present, decreased activity when they bind.
Photometer used to evaluate.

Question 23

Are miRNA blockers (lna inhibitors) tissue specific?

Answer 23

No.

Question 24

Do miRNA blockers associated with caridovascular diseases affect other organs? What is a potential consequence?

Answer 24

No,doesn’t affect their weight, and their morphology appears normal. Are involved in anti-tumour mechanisms however, blocking systemically could lead to oncogenesis. Also associated with healthy brain function.

Question 25

What is an miRNA sponge?

Answer 25

Molecule with multiple miRNA binding sites, competitive inhibitors to miRNA.

Question 26

What kind of miRNA do miRNA sponges target?

Answer 26

Soaks endogenous niRNA.

Question 27

How many binding sites does an miRNA sponge have, and how can it be delivered?

Answer 27

4-10 binding sites.

Can be delivered using AAVs.