Objective
The research team will pursue three interconnected objectives to test their hypothesis:
Objective 1: Preparing a library of insulin analogs using various Glut inhibitors for in vitro evaluation. Specifically, we
will synthesize/purchase up to 8 Glut inhibitors. Based on the specific chemical structures of these inhibitors, we
will further tailor their structures accordingly for facilitating their subsequent conjugation to insulin at various
positions (A1, B1, and/or B29). After obtaining these insulin analogs, the in vitro Glut- and IR-binding ability and
kinetics will be evaluated in various types of cells or cell membranes. Based on the in vitro study, insulin analogs
with suitable properties will be selected for further in vivo study.
Objective 2: Obtaining insulin analogs with significantly improved BG regulation ability and biocompatibility in
animal models. The in vivo BG regulation ability of the selected insulin analogs will be evaluated in both type 1
diabetic mice and healthy mice. The impact of insulin conjugates’ IR-binding ability, Glut-binding ability, and water
solubility on the glucose regulation ability and hypoglycemia risk will be investigated and used for guiding the
further optimization of insulin analog structure. Then, we will select the most promising insulin analogs and
evaluate them in type 1 diabetic minipigs.
Objective 3: Incorporating insulin conjugates into MN patch/or oral formulation with improved bioavailability. In this
aim, we will study MN patch/or oral formulation for delivering the optimized insulin analogs. Insulin analogs will be
loaded into a MN patch using an in-situ polymerization method. In type 1 diabetic mouse and minipig models, the in
vivo glucose regulation ability and hypoglycemia risk will be studied. Also, the biocompatibility of the MN patch will
be evaluated in animal models. Meanwhile, we will also apply various carriers or absorption enhancers, such as
ionic liquid to delivery insulin analogs orally.
Background Rationale
The PI is an expert in developing synthetic glucose-responsive insulin delivery systems, mimicking the function of pancreatic beta cells. Diabetes currently affects over 417 million people in the world. A glucose-responsive delivery system that is able to “secrete” insulin in response to blood-sugar level changes is highly desirable to improve health and quality of life for people with diabetes. So far, the PI's team has achieved significant accomplishments in this field. Particularly, the team invented “smart insulin patch” (PNAS, 2015), which was highlighted by both Science and Nature. This patch uses a painless microneedle-array loaded with glucose-responsive formulation/matrix. This smart patch can effectively regulate the blood glucose of diabetic mice and pigs (>25 kg) and reduce risk of hypoglycemia. Additionally, the team further engineered synthetic beta cells, for the first time, mimicking the cellular vesicle-fusion process for controlled drug delivery. Recently, the team developed a glucose-responsive insulin molecule by simply conjugating insulin and glucose transporter inhibitor together, especially for mitigating hypoglycemia. This proposal is based on the preliminary study associated with the glucose transporter (Glut) inhibitor-modified insulin analogs for glucose-responsive insulin delivery in mice and minipigs (Wang et al., PNAS, 22(10744)). The team will screen up to 8 different Glut inhibitors for synthesizing new insulin conjugates. A systemic study of this library of insulin analogs with varied Glut inhibitors at different modification sites will be performed to provide guidelines about the relationship between structures and properties. In addition, the team will study MN patch/or oral formulation for delivering the optimized insulin analogs.
Description of Project
For Type 1 diabetics, the frequent self-administration of multiple insulin injections through the day and regular monitoring of blood glucose (BG) levels is necessary to sustain life. This type of insulin therapy, known as open loop insulin delivery, cannot mimic normal physiological conditions in which the pancreas quickly releases insulin in response to a peak in BG levels commonly observed, for example, after a meal. A therapeutic system able to automatically regulate insulin continuously, and in proportion to BG levels is therefore a highly desirable alternative to insulin injections. The rationale of this proposal is based on our preliminary study for glucose-responsive insulin delivery based on the glucose transporter (Glut) inhibitor-modified insulin analogs. We will screen up to 8 different Glut inhibitors for synthesizing new insulin conjugates. Then, a systemic study of this library of insulin analogs with varied Glut inhibitors at different modification sites will be performed to provide guidelines about the relationship between structures and properties. In addition, a new preparation method of microneedle array patch will be developed to increase insulin analog loading content, making it applicable for mice and minipig study. Furthermore, oral delivery formation will also be designed and tested. The goal of this research is a breakthrough closed-loop system and next-generation artificial pancreases. The aims of this proposed research have a significant impact on improving the quality of life of Type 1 diabetics.
Anticipated Outcome
Our research design consists of four interconnected experimental components: A) Glut inhibitors and insulin
analogs synthesis; B) design and preparation of oral carrier/MN array patch integrated with insulin analogs; C) in
vitro test of insulin analogs; and D) in vivo evaluation of formulations and devices. The Glut inhibitors and insulin
analogs synthesis involves preparing various Glut-inhibitors with suitable functional groups and conjugating these
inhibitors to insulin. The design and preparation of oral carrier/MN array patch integrated with insulin analogs
include loading insulin analog into mesoporous silica particles (MSN)/ionic liquid capsule or MN array patch for oral
and transdermal administration, respectively. The in vitro test of insulin analogs measures the glucose-responsive
binding and glucose-responsive glucose-transport activity toward various cells or cell ghosts; The in vivo
component involves the use of the type 1 diabetic mice and minipigs to evaluate the performance of formulations
and devices, including BG regulation ability, pharmacokinetics, pharmacodynamics, GTT-response speed, and
biocompatibility.
Relevance to T1D
The proposed aims, when successfully realized, will be a significant upgrade over the current insulin-based therapy
options for Type 1 diabetics and dramatically improve patients’ life quality, and the relevant formulations/devices
will be immediately optimized and performed in clinical studies.