HCV 2

Question 1

HCV treatment indications

Answer 1

-chronic liver inflammation
-presence of hcv rna in the blood=active infection

Question 2

gola of hcv treatment

Answer 2

eliminate detectable ciral rna from the blood (viral clearance or sustained virological response =cure)

Question 3

all early protocols for HCV treatment were based on:

Answer 3

all early protocols for HCV treatment were based on IFN-⍺ administered by injection
- Modified (pegylated) form slows elimination (1/week)
* Treatments are for 24-48 weeks, hey had to do the treatments multiple times a week
* Severe side effects:
- Flu-like symptoms, depression, anxiety, restlessness, rashes,
insomnia, loss of appetite, anemia, etc.
* 30-40% of patients respond to peg-IFN⍺ alone

Question 4

Ribavirin

Answer 4

• Synthetic nucleoside
• looks like guanine (pseudobase)
• Side effects:
• Anemia, teratogenic, fatigue,
  headache, insomnia, nausea, anorexia,
  etc.
• Broadly antiviral, not effective against HCV
  when given alone

Question 5

Ribavirin + peg-IFN⍺

Answer 5

• ~50% sustained virological response (SVR)
• But: 10-20% of patients do not complete therapy due to side effects
• $4000 USD/week

Question 6

Direct acting antivirals: DAAS

Answer 6

facilited by out ability fo do cell cultures
-protease inhibitor
-ns5a inhibitor and polymerase inhibitor

Question 7

NS3 Protease Substrate-Based
Rational Inhibitor Design

Answer 7

N6terminal’product’inhibiGon’is’observed’for:’
‘
‘’’’’’’’’’'’D D I V P C (Ki’=’79’μM)

Question 8

Protease: NS3/4A inhibitors

Answer 8

select for substrate to block ns3
no cleaving of the polyproteins
-ex: boceprevir and telaprevir

Question 9

boceprevir and telaprevir

Answer 9

• Boceprevir and Telaprevir (FDA approved 2011)
• used in combination with
  peg-IFN⍺/RBV
• Significant side effects
• Specific for genotype 1
• Sustained response rates in 50-70%
• HCV is highly mutable!
• viral resistance can (quickly) emerge

Question 10

polymerase: NS5B inhibitors

Answer 10

• Sofosbuvir (FDA approved 2013)
• Nucleoside inhibitor (U analog)
• Mechanism: chain termination
• 12-wk duration; pan-genotypic
  ‣ ≥90% SVR for genotype 1, ~82% SVR for genotype 4
• Cost: ~$80,000/course of treatment

Question 11

True or false: resistance to sofosbuvir is rare

Answer 11

true

Question 12

NS5A inhibitirs

Answer 12

NS5A: Phosphoprotein, roles in inhibition of antiviral responses, RNA replication (interacts with 3’ end of the viral RNA and NS5B) and assembly
-precise mechanisms not clear
-ex: daclatasvir and ledipasvir

Question 13

daclatasvir and ledipasvir

Answer 13

• 12-wk duration; pan-genotypic
• Combination therapy (IFN-free)
• ≥94% SVR for genotype 1
• high barrier to resistance
• Cost ~$80,000/course of treatment

Question 14

which virus is the most mutable

Answer 14

hep c

Question 15

Selection of hcv drug resistance

Answer 15

Viral Turnover: 10 ^11-10^12 viruses/day x 10^-5 -10 ^-4 pol error rate x 104 nt

Base Variants: each base can mutate to 3 other (10^4 nt genome)

Question 16

genetic variation hcv

Answer 16

• HCV exists as a mixture of
  populations of genetically distinct,
  but closely related, virions in every
  patient (quasispecies)
• Most resistant viruses are relatively
  unfit and are undetectable prior to
  therapy

Question 17

Many factors determine the treatment response

Answer 17

• Virus: the genetic barrier is related to the number and type of mutations required to overcome the clinical activity of a regimen (mutations that decrease the viral fitness increase
  the resistance barrier)
• Drug(s): the pharmacologic barrier is increased by higher potency and higher drug levels
• Patient: tolerability of a regimen and patient adherence are critical to treatment success

Question 18

what is a barrier to hcv treatments

Answer 18

so expensivbe
shit healthcare
lack of education
touches more marginalized group
hard to diagnoase

Question 19

True or false: HCV exists as a quasispecies

Answer 19

true n
- resistant variants to antiviral drugs exist before treatment
- resistant variants can be selected/enriched during treatment
- drug resistance can occur during treatment with all (or any) antiviral drug
- resistance is a consequence of treatment failure (but not always the cause)

Question 20

WHAT ARE MICRORNA

Answer 20

• Small, non-coding RNAs (20-25 nt)
• Bind to partially complementary sites
  (seed sequences) in the 3’ end of
  mRNAs and block their translation
• Typically turn OFF gene expression
• Expressed in a tissue-specific
  manner
• Regulate ~50-60% of ALL human
  genes

Question 21

miR-122

Answer 21

• Evolutionarily conserved, liver-specific microRNA
• 70% of microRNAs in the liver (66 000 copies/cell)
• Regulates cholesterol synthesis and fatty acid metabolism

Question 22

mir-122 iteracts with what?

Answer 22

the 5’ utr of the hcv genome which is weird
-there are w microrna sites in proximity and this upregulates the virus when this happens where usually it should be downregulation it

Question 23

true or false: mir 122 downregulates hcv rna accumulation

Answer 23

false it promotes it
* Sequestration of miR-122 abolishes HCV RNA
accumulation
- Cell culture
- HCV-infected Chimpanzees
- HCV-infected patients

Question 24

mir 122 acts as a … to protect the HCV genome from degradation

Answer 24

as a cap so that pyrophosphatases and nucleases can’t reach the viral rna

Question 25

true or false: mir 122 alters the structure of the 5' end of the genome

Answer 25

facts it like makes these weird speudoknots so that nucleases can't reach it

Question 26

true or false: mir 122 promotes the hcv translaction

Answer 26

true it stabilizes the IRES

Question 27

how are the IRES made in hcv

Answer 27

mir 122 when the virus gets in the cell, site 1 and 2 are bp and then first mir 122 gets in and makes them go flat and you get and IRES and then a second comes in and then the IRES is stabilized

Question 28

Single-dose administration of RG-101(antisense miR-122 inhibitor)

Answer 28

Mean viral load reduction of 4.1 logs * 6/14 patients had viral RNA below the level of detection * Pan-genotypic activity * Side effects? - lowers cholesterol * Unique mechanism of targeting a host factor

Question 29

true or false: dogs can get infected by hcv

Answer 29

they can: canine hepacivirus

Question 30

from which animal might hcv come from

Answer 30

horseeee

Question 31

Non-primate hepacivirus (NPHV)

Answer 31

* Using CHV NS3 antigen, screened numerous mammalian species - 35% of horses seropositive - Renamed CHV = Non- primate hepacivirus (NPHV) * Tentative evidence for etiologic role of NPHV in hepatitis

Question 32

true or false: lots of animals can get hcv

Answer 32

true even sharks

Question 33

true or false: hcv might be a zoonotic virus

Answer 33

true

Question 34

Hypotheses regarding the origin of HCV

Answer 34

Hypothesis #1: Single cross-species transmission event between ancestral humans and a zoonotic host * Geographic populations * Global pattern of HCV diversity Hypothesis #2: Multiple independent zoonotic transmission events * RHVs: most genetically diverse (3 lineages, 8 clades), common ancestors with other animal hepacivirses, intermediate or original host? probs from rodents

Question 35

true or false: hepaciviruses could be transmissible via an insect vector or airborne

Answer 35

true