A & P Informational Literacy

The purpose of this project is for undergraduate pre-health students to think critically about the health information available to the public and their future communication with patients. Students will pick a piece of media - news article, blog post, social media meme, YouTube or TikTok video, etc. - that is aimed at the general public that makes some claim about human health. This is open ended on purpose, so students should do some searching and are encouraged to follow their interests or track down something related to health advice they heard recently or chose something that has come across their social media feeds. Students should NOT pick something for this that is from a highly recognizable name in health research - do NOT pick things from the CDC, John\u27s Hopkins, The Mayo Clinic, etc. - that is not the point, pick something you may kind of suspect of not having the best information. Students will then analyze this piece of media

Working a second job: Cell adhesion proteins that moonlight in the nucleus

Cells are adept at sensing changes in their environment, transmitting signals internally to coordinate responses to external stimuli, and thereby influencing adaptive changes in cell states and behavior. Often, this response involves modulation of gene expression in the nucleus, which is seen largely as a physically separated process from the rest of the cell. Mechanosensing, whereby a cell senses physical stimuli, and integrates and converts these inputs into downstream responses including signaling cascades and gene regulatory changes, involves the participation of several macromolecular structures. Of note, the extracellular matrix (ECM) and its constituent macromolecules comprise an essential part of the cellular microenvironment, allowing cells to interact with each other, and providing both structural and biochemical stimuli sensed by adhesion transmembrane receptors. This highway of information between the ECM, cell adhesion proteins, and the cytoskeleton regulates cellular behavior, the disruption of which results in disease. Emerging evidence suggests a more direct role for some of these adhesion proteins in chromatin structure and gene regulation, RNA maturation and other non-canonical functions. While many of these discoveries were previously limited to observations of cytoplasmic-nuclear transport, recent advances in microscopy, and biochemical, proteomic and genomic technologies have begun to significantly enhance our understanding of the impact of nuclear localization of these proteins. This review will briefly cover known cell adhesion proteins that migrate to the nucleus, and their downstream functions. We will outline recent advances in this very exciting yet still emerging field, with impact ranging from basic biology to disease states like cancer

Matrix metalloproteinase-14 is a mechanically regulated activator of secreted MMPs and invasion

Matrix metalloproteinases (MMPs) are extracellular matrix (ECM) degrading enzymes and have complex and specific regulation networks. This includes activation interactions, where one MMP family member activates another. ECM degradation and MMP activation can be initiated by several different stimuli including changes in ECM mechanical properties or intracellular contractility. These mechanical stimuli are known enhancers of metastatic potential. MMP-14 facilitates local ECM degradation and is well known as a major mediator of cell migration, angiogenesis and invasion. Recently, function blocking antibodies have been developed to specifically block MMP-14, providing a useful tool for research as well as therapeutic applications. Here we utilize a selective MMP-14 function blocking antibody to delineate the role of MMP-14 as an activator of other MMPs in response to changes in cellular contractility and ECM stiffness. Inhibition using function blocking antibodies reveals that MMP-14 activates soluble MMPs like MMP-2 and -9 under various mechanical stimuli in the pancreatic cancer cell line, Panc-1. In addition, inhibition of MMP-14 abates Panc-1 cell extension into 3D gels to levels seen with non-specific pan-MMP inhibitors at higher concentrations. This strengthens the case for MMP function blocking antibodies as more potent and specific MMP inhibition therapeutics

A survey-based analysis of the academic job market

Many postdoctoral researchers apply for faculty positions knowing relatively little about the hiring process or what is needed to secure a job offer. To address this lack of knowledge about the hiring process we conducted a survey of applicants for faculty positions: the survey ran between May 2018 and May 2019, and received 317 responses. We analyzed the responses to explore the interplay between various scholarly metrics and hiring outcomes. We concluded that, above a certain threshold, the benchmarks traditionally used to measure research success - including funding, number of publications or journals published in - were unable to completely differentiate applicants with and without job offers. Respondents also reported that the hiring process was unnecessarily stressful, time-consuming, and lacking in feedback, irrespective of outcome. Our findings suggest that there is considerable scope to improve the transparency of the hiring process

Mixed-surface, lipid-tethered quantum dots for targeting cells and tissues

Quantum dots (QDs), with their variable luminescent properties, are rapidly transcending traditional labeling techniques in biological imaging and hold vast potential for biosensing applications. An obstacle in any biosensor development is targeted specificity. Here we report a facile procedure for creating QDs targeted to the cell membrane with the goal of cell-surface protease biosensing. This procedure generates water-soluble QDs with variable coverage of lipid functional groups. The resulting hydrophobicity is quantitatively controlled by the molar ratio of lipids per QD. Appropriate tuning of the hydrophobicity ensures solubility in common aqueous cell culture media and while providing affinity to the lipid bilayer of cell membranes. The reaction and exchange process was directly evaluated by measuring UV-vis absorption spectra associated with dithiocarbamate formation. Cell membrane binding was assessed using flow cytometry and total internal reflection fluorescence imaging with live cells, and tissue affinity was measured using histochemical staining and fluorescence imaging of frozen tissue sections. Increases in cell and tissue binding were found to be regulated by both QD hydrophobicity and surface charge, underlying the importance of QD surface properties in the optimization of both luminescence and targeting capability.NOTICE: This is the author’s version of a work that was accepted for publication in Colloids and Surfaces B: Biointerfaces. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Colloids and Surfaces B: Bioinerfaces, 94, 1, (2012): doi: 10.1016/j.colsurfb.2012.01.015.</p

Microenvironment regulation of matrix metalloproteinase activity in pancreatic cancer cells

Currently there are no reliable treatment options for cancer metastasis. The complex cascade of events leading to metastasis reveals a multitude of therapeutic targets, but few of these targets are extensively involved in as many steps as the matrix metalloproteinases (MMPs). The MMP family is the major extracellular matrix (ECM) remodeling enzymes utilized by normal and cancerous cell alike. A therapeutic technique aimed at MMPs has been the subject of much research, but remains elusive due to two major concerns: 1) MMPs are post-translationally activated, usually by other MMPs, resulting in convoluted catalytic networks where activity does not equate expression, and 2) lack of knowledge of both the specific and redundant roles of MMPs in particular microenvironments. Here I address both these concerns by using specific MMP activity probes and inhibitors to study how MMP activity is regulated by a variety of microenvironmental conditions including modulating both the ECM and the signaling factors available to the cells. With this study I have been able to demonstrate novel regulation of MMP activity by ECM stiffness and cellular contractility in pancreatic cancer cells. This response is mediated through a specific MMP, membrane-tethered one MMP (MT1-MMP), which activates secreted MMPs in response to mechanical stimulation. Finally I have shown that MMP activities are differentially modulated by growth factor stimulation and that whole cell MMP activity does not always correlate with localized ECM degradation. These findings bring cancer metastasis research another step closer to being able to effectively target MMPs for therapy.</p

Cellular contractility and extracellular matrix stiffness regulate matrix metalloproteinase activity in pancreatic cancer cells

The pathogenesis of cancer is often driven by local invasion and metastasis. Recently, mechanical properties of the tumor microenvironment have been identified as potent regulators of invasion and metastasis, while matrix metalloproteinases (MMPs) are classically known as significant enhancers of cancer cell migration and invasion. Here we have been able to sensitively measure MMP activity changes in response to specific extracellular matrix (ECM) environments and cell contractility states. A pancreatic cancer cell line, Panc-1 cells, up-regulate MMP activities between 3- and 10- fold with increased cell contractility. Conversely, they down-regulate MMP activities when contractility is blocked to levels seen with pan-MMP activity inhibitors. Similar, albeit attenuated responses are seen in other pancreatic cancer cell lines: BxPC-3 and AsPC-1 cells. In addition, MMP activity was modulated by substrate stiffness, collagen gel concentration and the degree of collagen crosslinking, when cells were plated on collagen gels ranging from 0.5-5 mg/ml that span the physiological range of substrate stiffness (50-2000 Pa). Panc-1 cells showed enhanced MMP activity on stiffer substrates, whereas BxPC-3 and AsPC-1 cells showed diminished MMP activity. In addition, eliminating heparan sulfate proteoglycans using heparinase completely abrogated the mechanical induction of MMP activity. These results demonstrate the first functional link between MMP activity, contractility and ECM stiffness and provide an explanation as to why stiffer environments result in enhanced cell migration and invasion.This is a manuscript of an article from FASEB Journal 28 (2014): 3589, doi: 10.1096/fj.13-245613. Posted with permission.</p

Matrix metalloproteinase-14 is a mechanically regulated activator of secreted MMPs and invasion

Matrix metalloproteinases (MMPs) are extracellular matrix (ECM) degrading enzymes and have complex and specific regulation networks. This includes activation interactions, where one MMP family member activates another. ECM degradation and MMP activation can be initiated by several different stimuli including changes in ECM mechanical properties or intracellular contractility. These mechanical stimuli are known enhancers of metastatic potential. MMP-14 facilitates local ECM degradation and is well known as a major mediator of cell migration, angiogenesis and invasion. Recently, function blocking antibodies have been developed to specifically block MMP-14, providing a useful tool for research as well as therapeutic applications. Here we utilize a selective MMP-14 function blocking antibody to delineate the role of MMP-14 as an activator of other MMPs in response to changes in cellular contractility and ECM stiffness. Inhibition using function blocking antibodies reveals that MMP-14 activates soluble MMPs like MMP-2 and -9 under various mechanical stimuli in the pancreatic cancer cell line, Panc-1. In addition, inhibition of MMP-14 abates Panc-1 cell extension into 3D gels to levels seen with non-specific pan-MMP inhibitors at higher concentrations. This strengthens the case for MMP function blocking antibodies as more potent and specific MMP inhibition therapeutics.This is a manuscript of an article published as Haage, Amanda, Dong Hyun Nam, Xin Ge, and Ian C. Schneider. "Matrix metalloproteinase-14 is a mechanically regulated activator of secreted MMPs and invasion." Biochemical and biophysical research communications 450, no. 1 (2014): 213-218. DOI: 10.1016/j.bbrc.2014.05.086 . Copyright 2014 Elsevier Inc. Posted with permission.</p

Mixed-surface, Lipid-tethered Quantum Dots for Targeting Cells and Tissues

Quantum dots (QDs), with their variable luminescent properties, are rapidly transcending traditional labeling techniques in biological imaging and hold vast potential for biosensing applications. An obstacle in any biosensor development is targeted specificity. Here we report a facile procedure for creating QDs targeted to the cell membrane with the goal of cell-surface protease biosensing. This procedure generates water-soluble QDs with variable coverage of lipid functional groups. The resulting hydrophobicity is quantitatively controlled by the molar ratio of lipids per QD. Appropriate tuning of the hydrophobicity ensures solubility in common aqueous cell culture media and while providing affinity to the lipid bilayer of cell membranes. The reaction and exchange process was directly evaluated by measuring UV-vis absorption spectra associated with dithiocarbamate formation. Cell membrane binding was assessed using flow cytometry and total internal reflection fluorescence imaging with live cells, and tissue affinity was measured using histochemical staining and fluorescence imaging of frozen tissue sections. Increases in cell and tissue binding were found to be regulated by both QD hydrophobicity and surface charge, underlying the importance of QD surface properties in the optimization of both luminescence and targeting capability.NOTICE: This is the author’s version of a work that was accepted for publication in Colloids and Surfaces B: Biointerfaces. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Colloids and Surfaces B: Bioinerfaces, 94, 1, (2012): doi: 10.1016/j.colsurfb.2012.01.015.</p