Breaking News
April 20, 2018 - A potential “male pill” without side effects
April 20, 2018 - Researchers discover new information related to rare form of leukemia
April 20, 2018 - Researchers find crucial links between dopamine and avoidance behavior
April 20, 2018 - UGA scientist creates system for efficient detection of foodborne pathogens
April 20, 2018 - Social Support of Autonomy Tied to Better Glycemic Control in DM
April 20, 2018 - Study reports use of nutritional ketosis with mobile app intervention could reverse Type 2 diabetes
April 20, 2018 - New microscopy techniques allow quasi-biochemical studies on living T cells
April 20, 2018 - Study shows connection between muscular strength and brain health
April 20, 2018 - Ecolab introduces Life Sciences cleanroom program in North America
April 20, 2018 - Male fruit flies like sex and alcohol
April 20, 2018 - Improving job prospects unlikely to control opioid epidemic
April 20, 2018 - Skin Sensor Might Someday Track Alcoholics’ Booze Intake
April 20, 2018 - The relevance of GABA for diabetes highlighted in two new studies
April 20, 2018 - Novel method enables fast and noninvasive assessment of tumor status
April 20, 2018 - IU psychologist receives NIH grant to study earliest phases of language learning in children
April 20, 2018 - Walking fast lowers risk of hospitalization in heart patients, shows study
April 20, 2018 - Young victims of cyberbullying twice as likely to attempt suicide and enact suicidal behavior
April 20, 2018 - Role of UBE3A enzyme in Angelman syndrome
April 20, 2018 - NovaDigm Therapeutics initiates NDV-3A Phase 2a study for reduction of S. aureus in military trainees
April 20, 2018 - High-tech microscope reveals how cancer-causing virus anchors itself to human DNA
April 20, 2018 - Experimental compound reduces destructive inflammation to improve stroke outcome
April 20, 2018 - The May issue of Drug Discovery Today is a Special Issue and will be published very soon
April 20, 2018 - Larger families linked to heightened tooth loss risk for moms
April 20, 2018 - Scientists develop tiny fluorescent probe that seeks out GLUT5 and detects cancer cells
April 20, 2018 - The Swedish Childhood Cancer Foundation awards grant to KI researchers
April 20, 2018 - AMSBIO’s MC-Easy minicircle technology allows sustained transgene expression in quiescent cells and tissues
April 20, 2018 - Researchers use optogenetics to treat chronic pain
April 20, 2018 - Discovery of 100 new genes may aid research into pigmentation
April 20, 2018 - AYOXXA introduces new LUNARIS Mouse 12-Plex Th17 Kit for quantitative analysis of Th17 cell biology
April 20, 2018 - Compound derived from immune cells treats psoriasis in mice
April 20, 2018 - GABA-transaminase deficiency – Genetics Home Reference
April 20, 2018 - Key heart risks decline for older Americans
April 20, 2018 - UD professor wins $2.3 million grant from NIH for research on Achilles tendinopathy
April 20, 2018 - Researchers discover unique protein in malaria parasite that could be new drug target
April 20, 2018 - Bio-Techne expands automation capabilities of popular RNAscope ISH technology
April 20, 2018 - Smartphone app effective in promoting proper child car seat practices
April 20, 2018 - Nutraceuticals could play an important role in preventing heart disease
April 20, 2018 - FDA Alert: Certain Kratom-Containing Powder Products by Viable Solutions: Recall -Possible Salmonella Contamination
April 20, 2018 - What is heart failure?
April 20, 2018 - TIP Biosystems introduces handheld UV-Visible spectrophotometer for photometric measurements
April 20, 2018 - Inactivity of astronauts during spaceflights may have more pronounced effect on skeletal muscle than hypoxia
April 20, 2018 - New SIDS Info app seeks to reduce infant sleep-related deaths
April 20, 2018 - Wide-scale distribution of naloxone effectively prevents overdose deaths, study finds
April 20, 2018 - Triple-negative breast cancer found to be chemoresistant prior to treatment
April 20, 2018 - ACL tears occur the same way in women and men, study finds
April 20, 2018 - UT Southwestern researchers identify 170 potential therapeutic targets for lung cancer
April 20, 2018 - Finding the ‘keyhole’ to beat obesity at the cellular level
April 20, 2018 - Long-term exposure to cold temperatures reduces diabetes and obesity, shows study
April 20, 2018 - Metabolic Syndrome Common With Chronic Hep B Infection
April 20, 2018 - Tracking quality of life during prostate cancer treatment
April 20, 2018 - Study shows presence of beta-amyloid dimers in the brains of Alzheimer’s patients
April 20, 2018 - Researchers identify link between physical inactivity and increased risk of dying from cancer
April 20, 2018 - Breathtaking evolution amongst Indonesian tribe
April 20, 2018 - Study shows testosterone deficiency in men is associated with chronic diseases
April 20, 2018 - Simple one-page form helps improve satisfaction of patients with care
April 20, 2018 - Researchers evaluate accuracy of simple blood test to predict lung cancer
April 20, 2018 - Study looks at sperm producing ability in testicular cancer patients
April 20, 2018 - Exercise In, Vitamin D Out for Preventing Falls: U.S. Panel
April 20, 2018 - Skin cancers associated with decreased risk of developing AD
April 20, 2018 - Preserving fertility during chemotherapy
April 20, 2018 - Teva and Procter & Gamble Company terminate PGT Healthcare partnership
April 20, 2018 - People diagnosed with traumatic brain injury may have increased risk of Parkinson’s disease, shows study
April 20, 2018 - Researchers use smartphone to diagnose people infected with Loa loa worm
April 20, 2018 - College students with autism have high rate of suicidal thoughts
April 20, 2018 - Study sheds light on how the HSC niche is maintained
April 20, 2018 - Drug test spurs frank talk between hypertension patients and doctors
April 19, 2018 - Low-cost deworming drug improves female farmers’ physical fitness
April 19, 2018 - Genome editing identifies neural circuit behind leptin’s anti-obesity and anti-diabetes effects
April 19, 2018 - Many European countries lack comprehensive policy to eliminate viral hepatitis
April 19, 2018 - Young people with ADHD ‘more likely’ to come from deprived neighbourhoods
April 19, 2018 - SLU professor discovers new biomarkers for chlorine gas exposure
April 19, 2018 - Study proposes new mechanism that may contribute to gender differences in weight control
April 19, 2018 - Sleep restriction therapy does not interfere with insomnia patient’s driving ability, research shows
April 19, 2018 - Deep brain stimulation offers relief to UTHealth patient with treatment-resistant depression
April 19, 2018 - Study shows fatty fish and camelina oil boost HDL and IDL cholesterol
April 19, 2018 - FDA Alert: Euphoric Capsules by Epic Products: Recall
April 19, 2018 - Researchers identify peptide produced during cartilage deterioration as a potential source of osteoarthritis pain
April 19, 2018 - New breakthrough may allow scientists to orchestrate tissue regeneration in humans
April 19, 2018 - SYGNIS AG introduces new TruePrime apoptotic cell free DNA amplification kit
April 19, 2018 - Innovative device shows promise in capturing and releasing circulating tumor cells
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