Research Terms
This antigen-specific microparticle therapy is a robust and highly efficacious, localized treatment for multiple sclerosis (MS) without provoking global immunosuppression. MS is the most common, potentially disabling, neurological disease typically affecting young adults. About 400,000 people in the United States and about 2.5 million worldwide are affected by MS. In MS, immune cells target and destroy the protective covering (myelin) around the nerve cells causing autoimmune demyelination, thereby causing symptoms such as numbness in the limbs that may extend to a complete inability to walk, tremors and vision loss, amongst several others. Current limited therapeutic options involve use of steroids, which can cause global immunosuppression, and other poorly tolerated, disease-modifying therapies.
Researchers at the University of Florida have developed a combinatorial dual-sized polymeric microparticles (dMP) system loaded with specific MS-relevant antigens and tolerizing agents to modulate the dendritic cells of the immune system. The combination of smaller-sized particles for intracellular delivery and larger-sized particles for extracellular delivery of agents in a controlled release manner demonstrated complete protection against disease in the mouse model of MS, namely experimental autoimmune encephalomyelitis (EAE). Importantly, this microparticle-based system provides immune modulation without global systemic immunosuppression.
Highly efficacious antigen-specific immunomodulating treatment for multiple sclerosis without global immune suppression
Researchers at the University of Florida have developed antigen-specific, tolerizing treatment for MS. This is a combinatorial dual-sized MP system (dMP), encapsulating, MS specific antigens and agents selected for their capacity to modulate DC function: both through intracellular delivery of agents in phagocytosable small MPs, and subcutaneous local deposition of agents for controlled release in MPs too large to phagocytose. Disease blocking in mouse model of MS was associated with a reduction of infiltrating CD4+ T cells, inflammatory cytokine-producing pathogenic CD4+ T cells, and activated macrophages and microglia in the central nervous system. Furthermore, CD4+ T cells isolated from dMP-treated mice were anergic in response to disease-specific, antigen-loaded splenocytes. Our findings highlight the efficacy of localized microparticle-based drug delivery to mediate antigen-specific tolerance to block MS without global immunosuppression.
Drug delivery systems utilizing microparticle blends that incorporate poly(propylacrylic acid) into poly(lactide-co-glycolide) improve intracellular cytosolic delivery of bioactive molecules. The therapeutic potential of bioactive molecules delivered by microparticles is reduced considerably when the microparticles accumulate in cellular lysosomal compartments without being released into the cytoplasm. Poly(propylacrylic acid) displays pH-dependent membrane disruptive functionality at endo- lysosomal pH values. However, poly(propylacrylic acid) alone cannot support a matrix that encapsulates bioactive molecules. Researchers at the University of Florida have developed micro or nano particles that incorporate poly(propylacrylic acid) into poly(lactide-co-glycolide), creating an efficient vehicle to deliver bioactive molecules. The particle will experience pH dependent disruption when inside the desired cell. These poly(propylacrylic acid) blended poly(lactide-co-glycolide) particles show enhanced cytosolic drug delivery and induce a specific immune response to the particle enclosed antigen.
These poly(propylacrylic acid) poly(lactide-co-glycolide) blended particles improve efficiency of bioactive molecule delivery into eukaryotic cells
Therapeutic potential of bioactive molecules delivered by particles can be reduced considerably due to the non-availability of the therapeutic agent as a result of the accumulation of the particles containing the bioactive molecules in cellular lysosomal compartments following internalization by endocytosis or phagocytosis. To prevent this loss, the incorporation of poly(propylacrylic acid) into poly(lactide-co-glycolide) has demonstrated pH-dependent disruption and release of bioactive molecules into the cytosol, without cellular toxicity. These blended particles are biocompatible, biodegradable, and non-toxic. They are taken into the cells in the same route as pure poly(lactide-co-glycolide) particles even when poly(propylacrylic acid) is incorporated, and the particle matrix is disrupted due to the pH in the endolysosomal compartment. This allows for more efficient cytosolic delivery of antigens and therapeutic responses. These poly(lactide-co-glycolide)/ poly(propylacrylic acid) based particles can be developed as a vehicle to deliver small molecular drugs, genes/peptides to produce a DNA vaccine/immunotherapy for autoimmune diseases and cancer.
These nontoxic biomedical implants stabilize fractures or temporarily assist the healing of damaged bone. The body safely absorbs these devices once they are no longer needed. Composed of a magnesium alloy that contains calcium and strontium, these implants not only mimic natural bone's mechanical properties, but also promote osteoblast cell function to speed recovery times. When certain orthopedic problems do not respond to conservative treatment, surgical implants can reduce pain and increase mobility. In developed countries, an aging population and increasing obesity rates fuel the need for more of these types of surgical interventions. Forecasts project the global orthopedic implants market to reach $6.2 billion by 2024. Researchers at the University of Florida have developed nontoxic implants that dissolve completely once the body has repaired itself. The implants also promote faster healing times and decreased risk to healthy bone tissue from "stress shielding," where overly rigid implants absorb the stress that bones need to retain their strength.
Nontoxic magnesium alloy implants that stabilize fractures and promote new bone growth before dissolving
University of Florida researchers have invented a nontoxic magnesium alloy for biomedical applications that contains smaller amounts of calcium and strontium. While pure magnesium’s softness causes premature degradation, adding too much calcium or strontium leads to an overly rigid implant. Careful design has resulted in a final product that accurately mimics real bone tissue’s mechanical properties.
These cell-based arrays use a small sampling of cells to help isolate and identify a patient’s sensitivity to chemotherapeutic drugs in vitro, potentially personalizing treatment of cancer. The cancer stem cell hypothesis postulates that a minute fraction of cells within a tumor, termed cancer stem cells, possess the tumor-initiating capacity that propels tumor growth. Targeting tumor-initiating cells could be a viable clinical strategy to combating cancer, but these cells are extremely rare, necessitating new methods for rapid and robust screening. Researchers at the University of Florida have developed a miniaturized platform to investigate chemosensitivity of patient-derived tumor-initiating cells using limited cell numbers, potentially personalizing treatment of cancer. These cell-based arrays can predict the success of various combination treatments from one cancer patient to the next using just a small number of cells, thus enabling clinical adoption of personalized approaches to cancer.
Arrays to screen drug efficacy on rare cell populations, such as patient-derived colon cancer stem cells
Cancer stem cells with the greatest tumor-initiating and metastatic potential are exceptionally rare and difficult to isolate. The various embodiments of the arrays in this platform can perform chemosensitivity screens on patient-derived colon cancer stem cells using just a limited number of cells. University of Florida researchers found the results of using these structures and arrays indicate that colon cancer stem cells vary considerably in their response to drugs; this chemosensitivity screening on patient-derived cells can lead to valuable information regarding chemotherapy decisions. In addition to facilitating personalized medicine for treating colon cancer, any cancer stem cell or rare cellular population in which identifying responsiveness to drug combinations is paramount can adopt the same approach.
This bifunctional fusion protein resets the immune system to promote healthy tissue function by anchoring enzymes to the site of inflammation. Biologic drugs used to treat inflammatory diseases are a market that exceeds $30 billion annually. Available treatments to suppress inflammation are systemic, affecting unintended tissue and causing significant side effects. Localizing immunosuppressive drugs to sites of inflammation eliminates those problems.
Researchers at the University of Florida have developed a new approach to localize immunosuppressive enzymes to sites of inflammation. This technology platform is known as Galectin Anchors for Therapeutic Enzyme Retention. Specifically, they create a bifunctional fusion of an enzyme and galectin-3, a protein that binds to sugars decorating every tissue in our bodies. By binding to tissue sugars, Galectin-3 anchors the enzyme at the injection site. This prevents enzyme diffusion into surrounding tissue or entry into circulation. Their data show anchored enzyme formulations that persist at sites of inflammation for up to 2 weeks. Anchoring enzymes at the site of inflammation eliminates the side-effects that result from systemic distribution of drugs throughout the entire body.
The immunosuppressive enzyme utilized is indoleamine 2,3-dioxygenase (IDO), which breaks down the essential amino acid tryptophan into kynurenines. IDO naturally regulates the immune system in various contexts. For example, IDO establishes local maternal tolerance to the fetus to protect from immune attack without increasing host vulnerability to infection. Our bifunctional fusion protein resets the immune system to promote healthy tissue function by anchoring IDO to the site of inflammation, where it is administered. Restricting distribution of IDO avoids off-target side-effects and systemic immunosuppression.
Bifunctional fusion protein of galectin-3 and indoleamine 2,3-dioxygenase locally suppress inflammation
The bifunctional fusion protein, Gal3-IDO binds to tissue glycans to anchor the immunosuppressive enzyme at sites of inflammation. The inventors have demonstrated in in vivo models of osteoarthritis that Gal3-IDO can reduce inflammation, relieve pain, and restore gait. The inventors have demonstrated in in vivo models of periodontal disease that Gal3-IDO- can reduce inflammation and prevent the bone loss that leads to the need for tooth extraction. The inventors have demonstrated in in vivo models of bacterial endotoxin challenge that Gal3-IDO can shut down inflammation locally without systemic suppression.
This cell-based microarray allows testing of a wide range of biological or pharmaceutical agents on small numbers of cells from rare populations. Patient-derived cells such as cancer cells, stem cells and precancerous cells are difficult and expensive to obtain. Inefficient existing technologies only allow testing a few agents at a time on small populations of these rare cells, preventing large-scale testing. For example, colon cancer stem cells, recently identified as a potential cause of colon cancer, are of interest to many doctors and researchers who want to test the cells’ response to drugs. Because they are rare, researchers and drug companies can’t conduct large-scale testing on these cells. University of Florida researchers have developed a tool that allows the testing of multiple combinations of biological or pharmaceutical agents on small numbers of cells. Researchers will be able to test more agents without wasting these precious and expensive cells, reducing costs and increasing efficiency. The microarray separates the cells on a glass slide, allowing the user to test many agents at once: each agent targets just a portion of the cells on the slide.
A microarray for the application of multiple agents on a small amount of reagent cells
A microarray is a support (in this case, a glass slide) onto which molecules are attached in a regular pattern for use in biochemical or genetic analysis. In the microarray developed by UF researchers, thin films of timed-release polymer are loaded with testing agents and microarrayed onto solid substrates, providing a background that resists cell adhesion. This tool permits the testing of multiple biological and/or pharmaceutical agents and their various combinations on rare cell populations that are present in small quantities. On a given glass slide more than 1,000 spots can be arrayed, allowing for as many agents to be applied to the cell population of interest. Then, non-adherent or non-reactive cells are removed, leaving separated areas of the cells that showed adherence. Researchers can measure cellular response including proliferation and differentiation, through immunostaining or by using contrast agents.
