BME Seminar Series - Abdulaziz Fakhouri, Chris Bobba, & Lin Qi
"Development of a High Throughput 3D Hydrogel Encapsulation Assay to Measure Protease Activity in Breast Cancer Patients"
Three dimensional (3D) cell culture systems more closely mimic the in vivo cellular microenvironment than traditional two dimensional (2D) cell culture methods, making them a valuable tool in drug screening assays. However, 3D environments often make analysis of cellular responses more difficult, so most high throughput 3D assays have been limited to measurements of cell viability. Yet many other cell functions contribute to disease and are important pharmacological targets. Therefore, there is a need for new technologies that enable high throughput (HT) measurements of a wider range of cell functions for drug screening. We have developed a high throughput hydrogel system that enables cells to be cultured in a 3D environment and allows for the simultaneous detection of matrix metalloproteinase (MMP) and metabolic activities. MMPs are critical regulators of tissue homeostasis and are upregulated in many diseases, such as arthritis and cancer. This system was then characterized for utility in HT screening approaches, and validated utilizing a variety of cell types and human MMPs. Multiple drugs that are known to alter MMP activity were utilized in a range of concentrations with fibrosarcoma cell line to demonstrate the feasibility of the assay for HT applications. To measure MMP activity in breast cancer patients, adipose tissue dissections and fine needle aspirate biopsies (FNAB) were taken from patients undergoing breast lumpectomy or mastectomy surgeries and encapsulated in our 3D hydrogel system. Our high throughput 3D assay maintained viability for tissue samples and MMP and metabolic activity were measured, paving the road towards studying drugs effects on MMP and metabolic activity.
"Biomimetic hierarchic topographies with switchable superwettabilities for flow resistance modulation"
Superhydrophobic plant surfaces with various degrees of isotropic or anisotropic flow resistance are attracting great research interests. The unique wetting properties originate from the plant surfaces with low surface energy and hierarchic surface topographies. It is found that the difference of flow resistance/adhesion between the superhydrophobic plant surfaces is mainly due to their distinct topography characteristic dimensions. Therefore, when an engineering surface allows the modulation of topography dimensions, the surface wetting properties can be dynamically switched. This is beyond nature and enables new functions in various applications.
"miR-146a regulates alveolar macrophage mechanotransduction in ventilator induced lung injury"
Mechanical ventilation is an increasingly common intervention in the ICU and today about half of all patients receive it. Though critical for maintaining blood oxygenation, mechanical ventilation subjects the lung to high forces that cause damage. This is known as ventilator induced lung injury (VILI). VILI triggers inflammation and gross tissue damage, exacerbating the already precarious state of ICU patients. Previous work identified a novel mechanosensitive microRNA (miR-146a) in epithelial cells subjected to high mechanical force in vitro. Alveolar macrophages (AMs) are the resident immune cells in the lung and likely contribute to VILI. When subjected to injurious oscillatory pressure or stretching in vitro, AMs increase secretion of pro-inflammatory cytokines and increased their expression of miR-146a. Subsequent studies of VILI in vivo utilizing wild-type and miR-146a knockout mice revealed that AMs contribute to the injurious response seen in lungs during VILI and their response is significantly worse when they lack miR-146a. Overexpression of miR-146a via liposomal delivery dampened the injurious response. Taken together these findings demonstrate that alveolar macrophages directly and independently respond to high mechanical forces in a process regulated in part by miR-146a. These data warrant further study as miR-146a may serve as a potential therapy or biomarker for VILI.