Recombinant Protein Therapeutics Flashcards
What are biotherapeutics?
Therapies derived from living organisms used to treat chronic diseases
What’s a crucial incentive for innovation into new medicines?
Strong intellectual property rights
What is the central tenet of Biotherapeutics?
Patient need = disease pathology + treatment agent + MoA + treatment development + treatment manufacture = Performance in Pts
What is diabetes mellitus?
Chronic hyperglycemia due to insulin deficiency, resistance or both
What is a late stage complication of DM?
Macrovascular disease - CAD, peripheral vascular disease & stroke
What can microvascular damage lead to?
Diabetic nephropathy & retinopathy
What is insulin secreted by?
Beta cells of pancreatic islets
What is insulin required for?
Storage & controlled release of chemical energy available from food
What is insulin’s primary target organ?
Liver >50%
What does liver store glucose as?
Glycogen
maintains blood glucose at 3.5 - 8.0 mmol/L
What chains make up the insulin monomer?
B - 30aa
A -21aa
Why does the monomer have to stay in its specific shape?
Has to have this shape in order for it to be recognisable to insulin receptors on hepatocytes
How many aa does the insulin molecule contain?
51
When does the insulin molecule assemble into hexamers?
In the presence of zinc
Amitosole rings arise from side chains from histadines and circles around sphere of zinc
What is the hexamer?
Inactive form with long - term stability - keeps it protected
What is the hexamer-monomer conversion?
The central aspects of insulin formulations for injection
Where is prepro insulin cleaved into proinsulin?
Golgi
What does proinsulin travel as?
Exosomes
How many insulin pathways are there?
2
What happens when insulin binds to the receptor?
hyperphosphorylation of cytoplasmic domains (serine & thyrine) - intermediate signalling proteins activated
Is glucose membrane permeable?
No
How does insulin act in a fasting state?
Regulate glucose release by liver
How does insulin act in a postprandial state?
Facilitates glucose uptake by fat & muscle
What is type 1 caused by?
Autoantibodies against pancreatic islet proteins
What is Type 2 caused by?
Age
obesity
ethnicity
family history
What diseases are type 2 associated with?
Obesity
hypertension
decreased HDL
hypertriglycerideameia
insulin resistance
What are 3 therapeutic modalities for T2DM?
Incretins
short acting insulin
long acting insulin
What is the MoA of short acting?
Pre-meal injection (sub cutaneous)
absorbed slowly (peak at 60-90 mins after)
May last too long leading to hypoglycaemia
What are 3 sort acting insulins?
Insulin lispro
insulin aspart
insulin glulisine
What is the change in insulin aspart?
Switched proline for an aspartic acid (-vely charged)
poor hexamer structure = rapid dissociation
What is the change in insulin lispro?
Switched position of 2 aa - instability created
What is insulin structure modified to in long lasting?
Delay absorption to prolong duration of action eg. insulin glargine
What is insulin glargine soluble as?
In a vial at pH 4 but precipitates when SC injected
How is insulin glargine engineered?
Replace Asp at 21 of A chain with glycine & adds 2 asparg. to end of B chain
What does insulin detemir have?
fatty acid tail - binds to serum albumin - slow dissociation kinetics from bound state - prolonged action
What can lysine form?
Lysine has an amino side chain - can form an ionic bond with another moiety - as long as there is no other lysines in the chain
What is combination therapy?
Multiple injection regiment with short acting insulin
longer lasting at night
What has Oramed POD technology been designed to?
Protect orally delivered proteins from unwanted enzymatic activity within GIT
Enhance absorption across intestinal wall
What are incretins?
Insulin response due to release of 2 peptide hormones from L cells in the intestine
What are 2 types of incretins?
GLP-1
Glucose dependent insulinotropic peptide
What are 2 peptide analogues of GLP-1?
Exenatide
Liguratide
What is the Moa of exenatide?
Promotes insulin release & inhibits glucagon - reduce appetite & gastric emptying & slows postprandial increase in glucose
How long is glucagon?
180aa
~21kDA
What is semaglutide?
Potent, long-acting GLP-1 administered SC once weekly
94% homology with native GLP-1
What are 3 structuraly changes in semaglutide?
- substitution of Ala with Ab at position 8 increases enzymatic stability (protects from DPP-4 degradation)
- attachment of linker & C18 dl-acid at position 26 ( strong albumin binding)
- substitution of Lys with Arg at position 34 prevents C18 fatty acid binding at wrong site
What is GLP-1 RAs to be the 1st line therapy for?
CV risk reduction in patients with T2DM with very high/high risk
Which insulin strains were produced in e.coli?
Humulin
exubera
isulin lispro
insulin glusine
insulin glargin
