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C4b-binding protein rescues beta-cells from islet amyloid polypeptide induced cytotoxicity

Byman, Elin (2015) MOBT01 20142
Degree Projects in Molecular Biology
Abstract
Type 2 diabetes is characterized by hyperglycemia and insulin resistance, which leads to increased production of insulin. Together with insulin the hormone peptide islet amyloid polypeptide (IAPP) is secreted, which is thought to be the cause of beta-cell death in later stages of type 2 diabetes. C4b-binding protein (C4BP) has been shown to upregulate IAPP fibrillation, which would lead to more mature fibrils that is a safer form of IAPP compared to IAPP oligomers. Treatment of rat pancreatic beta-cells (INS-1 832/13) with IAPP and the complement inhibitor protein C4BP resulted in increased cell survival of cells treated with C4BP and IAPP compared to only IAPP. Cell viability assays were performed by staining cells for apoptosis with... (More)
Type 2 diabetes is characterized by hyperglycemia and insulin resistance, which leads to increased production of insulin. Together with insulin the hormone peptide islet amyloid polypeptide (IAPP) is secreted, which is thought to be the cause of beta-cell death in later stages of type 2 diabetes. C4b-binding protein (C4BP) has been shown to upregulate IAPP fibrillation, which would lead to more mature fibrils that is a safer form of IAPP compared to IAPP oligomers. Treatment of rat pancreatic beta-cells (INS-1 832/13) with IAPP and the complement inhibitor protein C4BP resulted in increased cell survival of cells treated with C4BP and IAPP compared to only IAPP. Cell viability assays were performed by staining cells for apoptosis with Annexin V and for necrosis with Via-Probe and analyzed in flow cytometer. We have also seen that INS-1 832/13 cells treated with labeled IAPP and C4BP, analyzed in confocal microscopy, takes up IAPP and also C4BP together with IAPP in aggregates. From our results we can conclude that C4BP rescues beta-cells from IAPP cytotoxicity and the mechanism behind could be upregulation of IAPP fibrillation by C4BP or C4BP regulation gene transcription, which leads to cell survival. (Less)
Popular Abstract
Dying pancreas can be rescued by human produced protein

There is a worrying tendency around the world with increasing number of individuals that are diagnosed with type 2 diabetes. Type 2 diabetes develops with an unhealthy life style, where the cells in the body cannot take up and use sugar from the blood. Many other diseases are linked to type 2 diabetes like high blood pressure. There is a great interest to find the mechanisms behind the development of and during the disease to be able to find targets for new therapies.

Type 2 diabetes is a disease that usually develops later in life and is often caused by obesity. People with type 2 diabetes suffer from high blood sugar, which is due to the cells in the body are resistant against... (More)
Dying pancreas can be rescued by human produced protein

There is a worrying tendency around the world with increasing number of individuals that are diagnosed with type 2 diabetes. Type 2 diabetes develops with an unhealthy life style, where the cells in the body cannot take up and use sugar from the blood. Many other diseases are linked to type 2 diabetes like high blood pressure. There is a great interest to find the mechanisms behind the development of and during the disease to be able to find targets for new therapies.

Type 2 diabetes is a disease that usually develops later in life and is often caused by obesity. People with type 2 diabetes suffer from high blood sugar, which is due to the cells in the body are resistant against insulin and therefore cannot take up glucose. Insulin is a hormone that is produced by the cells in the pancreas called beta-cells. The same cells also produce another type of hormone called islet amyloid polypeptide or IAPP. This hormone is thought to be toxic to the cells in the pancreas in type 2 diabetes patients.

A protein called C4b-binding protein (C4BP), that is part of the innate immune system has been seen to bind to the toxic IAPP. We wanted to test if C4BP can rescue beta-cells from toxic IAPP by treating these cells with both C4BP and IAPP and investigate the amount of live and dead cells after treatment. Pictures of the beta-cells were also taken with microscope where C4BP has been labeled with a molecule that appears in green and IAPP has been labelled and appears in red.

C4BP rescues beta-cells
From our experiments we can see that C4BP added together with IAPP to beta-cells lead to better cell survival compared to beta-cell with only IAPP. With C4BP in the samples we could see that cells got recued up to 50%. We could also see from our microscopy pictures that IAPP can go inside of beta-cells, which also happens with IAPP in aggregates with C4BP. C4BP alone do not go inside of beta-cells.

We think that C4BP can have several effects on beta-cells that lead to increased cell survival with IAPP. IAPP is known to make pores in cells, which leads to cell death. By binding of C4BP to IAPP this pore formation may be inhibited. Aggregates of C4BP and IAPP that are taken up into beta-cells were observed and may indicate that C4BP can save cells from IAPP, even from the inside of the cell. This new data gives a border insight in the disease development of type 2 diabetes and how we may rescue beta-cells from dying and save many patients from suffering.



Advisor: Sara Nilsson, PhD
Degree project 60 credits in: Molecular biology with specialization in Medical biology, 2015
Department of Biology, Lund University (Less)
Please use this url to cite or link to this publication:
author
Byman, Elin
supervisor
organization
course
MOBT01 20142
year
type
H2 - Master's Degree (Two Years)
subject
language
English
id
7756560
date added to LUP
2015-08-07 14:57:58
date last changed
2015-08-07 14:57:58
@misc{7756560,
  abstract     = {Type 2 diabetes is characterized by hyperglycemia and insulin resistance, which leads to increased production of insulin. Together with insulin the hormone peptide islet amyloid polypeptide (IAPP) is secreted, which is thought to be the cause of beta-cell death in later stages of type 2 diabetes. C4b-binding protein (C4BP) has been shown to upregulate IAPP fibrillation, which would lead to more mature fibrils that is a safer form of IAPP compared to IAPP oligomers. Treatment of rat pancreatic beta-cells (INS-1 832/13) with IAPP and the complement inhibitor protein C4BP resulted in increased cell survival of cells treated with C4BP and IAPP compared to only IAPP. Cell viability assays were performed by staining cells for apoptosis with Annexin V and for necrosis with Via-Probe and analyzed in flow cytometer. We have also seen that INS-1 832/13 cells treated with labeled IAPP and C4BP, analyzed in confocal microscopy, takes up IAPP and also C4BP together with IAPP in aggregates. From our results we can conclude that C4BP rescues beta-cells from IAPP cytotoxicity and the mechanism behind could be upregulation of IAPP fibrillation by C4BP or C4BP regulation gene transcription, which leads to cell survival.},
  author       = {Byman, Elin},
  language     = {eng},
  note         = {Student Paper},
  title        = {C4b-binding protein rescues beta-cells from islet amyloid polypeptide induced cytotoxicity},
  year         = {2015},
}