Presentation Title

Analysis of the Effects of Human and Chicken IAPP on Pancreatic β-cells

Faculty Mentor

Dr. Luiza Nogaj

Start Date

17-11-2018 10:30 AM

End Date

17-11-2018 10:45 AM

Location

C161

Session

Oral 2

Type of Presentation

Oral Talk

Subject Area

biological_agricultural_sciences

Abstract

The aggregation of the 37-amino acid polypeptide human Islet Amyloid Polypeptide (hIAPP), as either insoluble amyloid or as small oligomers, appears to play a direct role in the death of pancreatic β-islet cells in type 2 diabetes. Whether this toxicity is a cause of type 2 diabetes or merely a side-effect remains unclear. If IAPP aggregation into toxic amyloid is on-path for developing Type 2 Diabetes, IAPP aggregation would likely need to play a similar role within other organisms known to develop the disease. Humans and chickens are organisms known to both aggregate IAPP and develop diabetes. Despite the significant amount of information available, no study has been conducted to correlate IAPP aggregation between two organisms known to both aggregate IAPP and develop diabetes, and the mechanism of damage by which cell viability decreases.

To study these potential mechanisms of damage, MTT Cell Viability and LDH Cytotoxicity assays were performed on HeLa and ASPC-1 cells treated with either Human or Chicken IAPP. The aggregation potentials between Human and Chicken IAPPs were also compared. In addition, the expression of protein targets involved in the Unfolded Protein Response (UPR) was studied using qPCR. Our results show that both human and chicken IAPP have a toxic effect on both cell lines. Both IAPP sequences also have the ability to aggregate. However, mixing of human and chicken IAPPs prevents cell toxicity and saves the cells from cell death. To examine the molecular mechanism behind this phenomenon, we analyzed the expression of UPR targets upon addition of human and chicken IAPPs. Our preliminary results suggest an upregulation of some UPR targets upon addition of chicken IAPP but not in the presence of human IAPP. Further analysis is necessary to determine the role the UPR targets play in human and chicken IAPP aggregation.

Summary of research results to be presented

HeLa and ASPC-1 cells were treated with Human IAPP, Chicken IAPP, or an equal mixture of both. MTT Cell Viability and LDH Cytotoxicity Assays were performed on these treated cells. It was found that Human IAPP alone dramatically reduced viability, and posed a great amount of cytotoxicity on both cell lines. Chicken IAPP reduced viability and increased cytotoxicity to a far lesser extent.

Upon addition of both Human and Chicken IAPP, cell viability and cytotoxicity levels were in a similar range as to when cells were treated with Chicken IAPP alone. It appears that Chicken IAPP "rescues" both cell lines from the toxic effects imposed by the Human IAPP.

In addition to the aforementioned cell viability and cytotoxicity results, we also have preliminary quantitative PCR results. We investigated the upregulation of gene targets involved in Unfolded Protein Response, including PERK, CHOP, GRP78 and XBP1. We have found that cells treated with Chicken IAPP alone undergo a higher upregulation of certain gene targets than cells treated with Human IAPP alone.

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Nov 17th, 10:30 AM Nov 17th, 10:45 AM

Analysis of the Effects of Human and Chicken IAPP on Pancreatic β-cells

C161

The aggregation of the 37-amino acid polypeptide human Islet Amyloid Polypeptide (hIAPP), as either insoluble amyloid or as small oligomers, appears to play a direct role in the death of pancreatic β-islet cells in type 2 diabetes. Whether this toxicity is a cause of type 2 diabetes or merely a side-effect remains unclear. If IAPP aggregation into toxic amyloid is on-path for developing Type 2 Diabetes, IAPP aggregation would likely need to play a similar role within other organisms known to develop the disease. Humans and chickens are organisms known to both aggregate IAPP and develop diabetes. Despite the significant amount of information available, no study has been conducted to correlate IAPP aggregation between two organisms known to both aggregate IAPP and develop diabetes, and the mechanism of damage by which cell viability decreases.

To study these potential mechanisms of damage, MTT Cell Viability and LDH Cytotoxicity assays were performed on HeLa and ASPC-1 cells treated with either Human or Chicken IAPP. The aggregation potentials between Human and Chicken IAPPs were also compared. In addition, the expression of protein targets involved in the Unfolded Protein Response (UPR) was studied using qPCR. Our results show that both human and chicken IAPP have a toxic effect on both cell lines. Both IAPP sequences also have the ability to aggregate. However, mixing of human and chicken IAPPs prevents cell toxicity and saves the cells from cell death. To examine the molecular mechanism behind this phenomenon, we analyzed the expression of UPR targets upon addition of human and chicken IAPPs. Our preliminary results suggest an upregulation of some UPR targets upon addition of chicken IAPP but not in the presence of human IAPP. Further analysis is necessary to determine the role the UPR targets play in human and chicken IAPP aggregation.