DIABETES STORY LSSI Alum, 2015 Shawn Hurley, San Diego Miramar College

What is diabetes? Physiological condition in which the cells of the body are not able to obtain glucose circulating in the blood Caused by an endocrine disorder in which the body does not properly use or produce sufficient quantities of the hormone known as insulin Hyperglycemia is one of first symptoms – requires constant monitoring of blood-glucose levels

How your body uses glucose The process of digestion chemically breaks down starch (complex carbohydrate) into the simple sugar known as glucose Glucose is next absorbed by cells of the gastrointestinal tract and then enters into the bloodstream where it is distributed to all cells of the body and used as fuel

How your body uses glucose (cont’d.) When glucose enters cells, it is metabolized (enzymatically broken down) in the presence of oxygen to make ATP (while releasing carbon dioxide and water) ATP = energy currency of the cell – used to perform work that keeps cells alive C 6 H 12 O 6 + O 2 ATP + CO 2 + H 2 O glucose oxygen adenosine carbon water (from food) (in air) triphosphate dioxide (fluid balance) (energy) (exhaled waste)

The importance of insulin Chemical messenger (hormone) produced by the pancreas (beta cells) Binds to receptors on the surface of cells triggering a signal pathway that results in the aggregation of glucose-transport proteins (GLUT 4) that create channels through which glucose can diffuse from blood into cells Summary: Without insulin/receptor binding, glucose cannot get from blood into cells resulting in energy deprivation and death

Type 1 diabetes Formerly known as insulin-dependent diabetes Results from destruction of pancreatic beta cells (due to autoimmunity) Insulin production of the pancreas is little to none Most common among individuals from northern European descent Onset usually before the age of 20 Treated with insulin injections

Type 2 diabetes Formerly known as non-insulin-dependent diabetes Results from 1) decreased insulin production or 2) desensitization of target cells to insulin Many type 2 diabetics have normal insulin levels Most common among obese individuals over the age of 35 Constitutes more than 90% of all diabetes cases Controlled through diet, weight loss, medications that lower blood glucose, or insulin injection

Sources of insulin – in the beginning For 60 years ( ) the only sources of insulin for use by diabetics were porcine (pig) and bovine (cow) – virtually identical to human insulin Initially, impurities in animal-derived insulin resulted in side effects (allergic reactions) With increased quality/purification, supply & demand became a concern in later years Thus, scientists began searching for new ways to synthesize human insulin efficiently in large quantities

Sources of insulin – a new era In 1982, scientists genetically engineered E. coli bacteria to produce human insulin Using recombinant DNA technology, the DNA sequence coding for human insulin protein was isolated and inserted into bacterial plasmid The recombinant DNA was then introduced into bacterial host cells Genetically modified microbes are currently primary source for commercially-synthesized human insulin produced in mass quantities

Making insulin in bacteria: a summary

A success story Although not a cure, recombinant human insulin serves as an excellent example of the utility and promise of genetic engineering as it is practically applied in the field of medicine Within the last four decades, genetic engineering has helped to advance agricultural, medical, and environmental sciences increased food production treatments for disorders/diseases bioremediation

Using insulin as a model The steps in recombinant insulin production serve as a template regarding the methodologies used in the Amgen lab series Plasmid restriction enzyme Digested plasmid foreign gene + ligase Recombinant plasmid recombinant plasmid Introduced into host “Transformed” E. coli cell cell divides Transcription & translation yields protein product from gene insert lyse cells; separate product from bacterial proteins Purified Protein Product

Additional Resources tes/abe.edc.org/files/abe_english_student_all _sequences_ pdf (pgs. A-7 through A- 12) tes/abe.edc.org/files/abe_english_student_all _sequences_ pdf