Breaking News
December 12, 2018 - Sacrificial immune cells alert body to infection
December 12, 2018 - Low-salt diet may be more beneficial for females than males
December 12, 2018 - Major soil organic matter compound battles chronic wasting disease
December 12, 2018 - Findings may open up new ways to treat dwarfism and other ER-stress-related conditions
December 12, 2018 - New computational model provides clearer picture of shape-changing cells’ structure and mechanics
December 12, 2018 - 10 Facts on Patient Safety
December 12, 2018 - Poorest dying nearly 10 years younger than the rich in ‘deeply worrying’ trend for UK
December 12, 2018 - Innovative care model for children with ASD reduces use of behavioral drugs in ED
December 12, 2018 - Spending time in and around Hong Kong’s waters linked to better health and wellbeing
December 12, 2018 - Simple measures to prevent weight gain over Christmas
December 12, 2018 - Research advances offer hope for patient-tailored AML treatment
December 12, 2018 - Researchers discover a ‘blind spot’ in atomic force microscopy
December 12, 2018 - Sprayable gel could help prevent recurrences of cancer after surgery
December 12, 2018 - SLU researchers explore how fetal exposure to inflammation can alter immunity in newborns
December 12, 2018 - How do patients want to discuss symptoms with clinicians?
December 12, 2018 - Zinc chelation may be able to deliver drug to insulin-producing cells
December 12, 2018 - Brigham researchers develop automated, low-cost tool to predict a woman’s ovulation
December 12, 2018 - Some people with Type 2 diabetes may be testing their blood sugar more often than needed
December 12, 2018 - Slow-growing type of glioma may be vulnerable to immunotherapy, suggests study
December 12, 2018 - Study provides new information regarding microRNA function in cellular homeostasis of zebrafish
December 12, 2018 - Study provides new understanding of mysterious ‘hereditary swelling’
December 12, 2018 - Researchers shed new light on how to combat Shiga and ricin toxins
December 12, 2018 - Pregnant Women Commonly Refuse Vaccines
December 12, 2018 - Drug treatment could offer new hope for some patients with brain bleeding
December 12, 2018 - Health care financial burden of animal-related injuries is growing, study says
December 12, 2018 - Macrophage cells could help repair the heart following a heart attack, study finds
December 12, 2018 - Researchers develop new system for efficiently producing human norovirus
December 12, 2018 - New artificial intelligence-based system to differentiate between different types of cancer cells
December 11, 2018 - Brazilian professors propose guidelines for therapeutic use of melatonin
December 11, 2018 - Healthy Lifestyle Lowers Odds of Breast Cancer’s Return
December 11, 2018 - New research identifies two genes linked to serious congenital heart condition
December 11, 2018 - NIH Director talks science, STEM careers with preteens
December 11, 2018 - Disabling a Cellular Antivirus System Could Improve Gene Therapy
December 11, 2018 - New tool swiftly provides accurate measure of patients’ cognitive difficulties
December 11, 2018 - NICE releases new guidelines for diagnosis and management of COPD
December 11, 2018 - Without Obamacare penalty, think it’ll be nice to drop your plan? Better think twice
December 11, 2018 - Researchers capture high-resolution X-ray and NMR image of key immune regulator
December 11, 2018 - Natural flavonoid is effective at treating leishmanisis infections, study shows
December 11, 2018 - Avoidant grievers unconsciously monitor and block mind-wandering contents, study shows
December 11, 2018 - Study identifies how hantaviruses infect lung cells
December 11, 2018 - Improving PTSD care through genetics
December 11, 2018 - Dermatology providers show interest in recommending cannabinoids to patients
December 11, 2018 - Researchers to study effects of electroconvulsive therapy on Alzheimer’s patients with aggression
December 11, 2018 - Four dried fruits have lower glycemic index than starchy foods, study finds
December 11, 2018 - Optimization of drug dose sizes can reduce pharmaceutical wastage
December 11, 2018 - Ultrarestrictive opioid prescribing strategy linked with reduction in number of pills dispensed
December 11, 2018 - PET scans to optimize tuberculosis meningitis treatments and personalize care, study finds
December 11, 2018 - Researchers aim to identify and target high blood pressure indicators
December 11, 2018 - Researchers identify immune cell subset that may drive chronic inflammation
December 11, 2018 - Ezogabine treatment reduces motor neuron excitability in ALS patients, study shows
December 11, 2018 - One implant, two prices. It depends on who’s paying.
December 11, 2018 - Standardizing feeding practices improves growth trends for micro-preemies
December 11, 2018 - COPD Tied to Obesity in Male, Female Never-Smokers
December 11, 2018 - Flossing: Information for Caregivers
December 11, 2018 - Does breastfeeding hormone protect against type 2 diabetes?
December 11, 2018 - Educating future doctors to prescribe physical activity for their patients
December 11, 2018 - Krystal 2000 microplate design improves fluorescence and luminescence measurement
December 11, 2018 - FDA clears mobile medical app to help increase retention in recovery program for opioid use disorder
December 11, 2018 - Overcoming Challenges in High-Speed Centrifugation Experiments
December 11, 2018 - Study shows link between neighborhoods’ socioeconomic status and dietary choices
December 11, 2018 - Lower BMI before obesity surgery predicts greater post-operative weight loss, study finds
December 11, 2018 - Obesity May Be Driving Rise in Uterine Cancers
December 11, 2018 - Antioxidants may prevent cognitive impairment in diabetes
December 11, 2018 - Study discovers link between meditation and how individuals respond to feedback
December 11, 2018 - Researchers identify potential diagnostic tool for Alzheimer’s disease
December 11, 2018 - Oral cancer prognostic signature identified
December 11, 2018 - How Can I Find Out What Caused My Miscarriage?
December 11, 2018 - Novel personalized medicine tool for assessing inherited colorectal cancer syndrome risk developed
December 11, 2018 - Study uncovers 11 new genes associated with epilepsy
December 11, 2018 - Filling research gaps could help develop more disability-inclusive workplaces
December 11, 2018 - Cartilage tissue engineering brings good news for patients with cartilage defects
December 11, 2018 - Novel 3D printing workflow helps predict leaky heart valves
December 11, 2018 - Imagination can help overcome fear and anxiety-related disorders, shows study
December 11, 2018 - Are caries linked to political regime?
December 11, 2018 - Leader in Diabetes Clinical Trials Wins Naomi Berrie Award
December 11, 2018 - Scientists discover cellular mechanism that triggers pneumonia in humans
December 11, 2018 - Increasing mental health problems related to drug use in over 55’s
December 11, 2018 - High-intensity interval exercise could help combat cognitive dysfunction in obese people
December 11, 2018 - Annual flu shot can save lives of heart failure patients
December 11, 2018 - Researchers compare health outcomes for VA and non-VA hospitals
Blood-vessel-on-a-chip provides insight into new anti-inflammatory drug candidate

Blood-vessel-on-a-chip provides insight into new anti-inflammatory drug candidate

image_pdfDownload PDFimage_print
Credit: Wyss Institute at Harvard University

One of the most important and fraught processes in the human body is inflammation. Inflammatory responses to injury or disease are crucial for recruiting the immune system to help the body heal, but inflammation can also cause an increase in the production of thrombin, which can lead to dangerous blood clots and other conditions. Activated protein C (APC) is a naturally occurring anti-coagulant protein with anti-inflammatory and other protective effects that has been used medically to treat severe blood infections and wounds; however, its use is limited because its inhibition of thrombin also impacts the blood’s ability to clot, increasing bleeding risk.

Now, a collaborative team of researchers from the Division of Hemostasis and Thrombosis at Beth Israel Deaconess Medical Center (BIDMC) and the Wyss Institute at Harvard University have discovered that synthetic APC-mimicking small molecules called “parmodulins” provide anti-inflammatory and anti-thrombotic protection to endothelial cells on par with APC’s without interfering with blood clotting, making them attractive new drug candidates. This work was enabled by leveraging the Institute’s Organ-on-a-Chip technology to model coagulation within a human blood vessel in vitro. The results are reported in this week’s issue of Proceedings of the National Academy of Sciences.

“We essentially performed a mini pre-clinical trial of parmodulins’ effect on the endothelium, and not only determined the pathway through which parmodulins function, but also demonstrated that they help protect endothelial cells from inflammatory damage,” says former Wyss postdoc Abhishek Jain, Ph.D., who is now an Assistant Professor and director of the the Bioinspired Translational Microsystems lab at Texas A&M University.

The target protein on which both APC and parmodulins act is the transmembrane protein protease-activated receptor 1 (PAR1), which is present on both endothelial cells that line blood vessels and platelets that circulate through the blood and promote clotting, making mechanistic analysis difficult. PAR1 was originally identified as a receptor for thrombin, which is a crucial part of the inflammatory process. However, when PAR1 is activated by APC on endothelium, it triggers anti-inflammatory, anti-apoptotic, and barrier-fortifying pathways, all of which help protect cells from the negative effects of inflammation.

In addition to activating PAR1, APC also independently inhibits the generation of thrombin, which is an essential component of healthy blood clotting – but inhibiting thrombin too much leads to uncontrolled bleeding. Knowing that parmodulins bind to PAR1, the team of scientists and clinicians set out to find a way to activate endothelial PAR1 and reduce thrombic responses without thinning the blood, and thus provide a better alternative to APC.

To evaluate the activity of parmodulins on endothelium, Karen De Ceunynck, Ph.D., postdoctoral research fellow at BIDMC and first author of the paper, incubated human endothelial cells with parmodulin 2 in vitro for 4 hours and then exposed them to the thrombin-inducing inflammatory agents lipopolysaccharide (LPS) or tumor necrosis factor-α (TNF-α). In the parmodulin-exposed cells, both agents’ ability to generate thrombin was reduced by over 50% compared with non-parmodulin-exposed cells. However, parmodulin 2 did not inhibit the activity of factor V or factor X, proteins that function in blood coagulation. “We were intrigued by the notion that parmodulin 2 inhibited LPS- and TNF-mediated prothrombotic effects on the endothelial surface without impairing blood clotting” says De Ceunynck.

Credit: Wyss Institute at Harvard University

To confirm this theory, the team used a Wyss-developed blood-vessel-on-a-chip consisting of microfluidic channels embedded in a clear polymer chip, coated with collagen, and lined by human endothelial cells. Whole blood was perfused through the chip to simulate the flow conditions within human blood vessels, to which were added different pro- and anti-inflammatory compounds to evaluate the response of the endothelium.

When the endothelial cells were exposed to TNF-α before being perfused with whole blood, platelets accumulated on the endothelium in a typical inflammatory response; if the cells were first exposed to parmodulin 2 and then TNF-α, platelet accumulation was inhibited and the endothelium resumed its normal function. These results indicated that parmodulin exposure blocks the thrombotic response of endothelium to inflammatory stimuli without affecting blood coagulation in humans – a significant improvement over APC.

A series of tests in vitro performed by co-first author Christian Peters, Ph.D. at BIDMC, confirmed that parmodulin 2’s activation of PAR1 also induces cytoprotective responses in endothelial cells by inhibiting apoptosis (programmed cell death) induced by thrombin, TNF-α, and the apoptotic alkaloid staurosporine through a signaling pathway that begins with parmodulin 2’s binding to a specific site on the cytoplasmic side of PAR1. “We observed that the cytoprotective response induced by parmodulin 2 happened very quickly, and confirmed its rapid onset in time course and gene expression assays,” says Peters.

Furthermore, in vivo studies in mice showed that parmodulin 2 reduces the binding of white blood cells to blood vessels and impairs platelet and fibrin accumulation at injury sites during the inflammatory response, confirming the anti-thrombotic and anti-coagulant activity of parmodulin 2 observed in vitro. Additionally, parmodulins do not interact with many of APC’s other binding partners, making it much more targeted to PAR1 and reducing other side effects.

“The discovery of an anti-inflammatory molecule that prevents endothelial thrombosis but also preserves normal blood coagulation is a major step toward an alternative and better approach to treating inflammatory disease,” says Rob Flaumenhaft, M.D., Ph.D., Professor of Medicine at Harvard Medical School, Chief of the Division of Hemostasis and Thrombosis at BIDMC, and corresponding author of the paper. “Furthermore, nearly all other pharmaceuticals that target G-protein coupled receptors like PAR1 bind to the exterior of the receptor; parmodulin 2 represents a paradigm shift for compounds targeting GPCRs because it acts on internal domains. We are excited to see if we can advance it to clinical trials.”

“This work provides another example of how organ-on-a-chip technology can enable faster and safer development and evaluation of drugs that could help patients around the world,” says co-author and Wyss Institute Founding Director Donald Ingber, M.D., Ph.D., who is also the Judah Folkman Professor of Vascular Biology at HMS and the Vascular Biology Program at Boston Children’s Hospital, as well as Professor of Bioengineering at Harvard’s John A. Paulson School of Engineering and Applied Sciences (SEAS).


Explore further:
Pulmonary Thrombosis-on-a-Chip provides new avenue for drug development

More information:
Karen De Ceunynck el al., “PAR1 agonists stimulate APC-like endothelial cytoprotection and confer resistance to thromboinflammatory injury,” PNAS (2018). www.pnas.org/cgi/doi/10.1073/pnas.1718600115

Journal reference:
Proceedings of the National Academy of Sciences

Provided by:
Harvard University

Tagged with:

About author

Related Articles