The team, which includes researchers at Washington University School of Medicine, the United States National Institutes of Health, the United States Food and Drug Administration as well as other researchers at Virginia Tech, has characterized HDP and demonstrated that it plays a major role in protecting Plasmodium as the pathogen pursues infection of its host. The findings were published April 25th in the open-access journal PLoS Pathogens.*
Worldwide, the annual death toll of malaria exceeds 1 million, and children under the age of five are its major victims. The Plasmodium parasite that causes malaria in humans is transmitted through the bites of infected mosquitoes. Once inside the human body, the parasite initially develops in the liver and subsequently, upon release, infects red blood cells. After infecting host red blood cells, a rapid growth ensues, supported by the parasite’s consumption of hemoglobin, the oxygen-transporting protein that constitutes a massive 90% of the total protein present inside each red blood cell.
Destruction on this scale releases large quantities of heme, the prosthetic group responsible for oxygen transport in hemoglobin. Free heme is extremely damaging and to protect itself from this toxic onslaught, the parasite utilizes a novel mechanism where it rapidly converts heme into a crystalline material known as hemozoin.
Dr. Dharmendar Rathore, Assistant Professor at VBI, remarked: “We discovered HDP as part of a functional genomics initiative that is focused on the identification of malaria proteins involved in disease pathology. A combination of cellular and biochemical approaches allowed us to rigorously characterize HDP. It appears that HDP has a number of striking features that make it a promising candidate as a drug target.
HDP is not only capable of rapidly converting heme into its non-toxic counterpart hemozoin, but it is highly conserved in all the species of the parasite and also appears to be critical for its survival.” He added: “The beauty of this discovery is that, while HDP has robust interactions with heme, it lacks homology to any of the known heme-binding proteins and has therefore eluded detection during previous attempts by several groups to identify parasite factors responsible for hemozoin formation.”
The conversion of heme into hemozoin is regarded as one of the weakest links in the lifecycle of the Plasmodium parasite. For example, chloroquine, the most widely used malaria drug, works by interacting with heme and preventing its detoxification into hemozoin. However drugs are not yet available that target any of the parasite-specific molecules involved in this process.
Dr. Rana Nagarkatti, research scientist at VBI, commented: “The identification of new drug targets is an essential step in the development of next-generation drugs for treating malaria. Drugs that specifically interact with HDP and inhibit its detoxification activities could potentially have drastic effects on the viability of the malaria parasite.” Dr. Dewal Jani, a member of the VBI research team, remarked: “The identification of HDP fills an important gap in our understanding of the mechanism of hemozoin production in the malaria parasite. We have also established the route by which the HDP is transported out of Plasmodium and into the red blood cell before it subsequently returns to the parasite food vacuole where hemozoin is synthesized. This gives us an interesting insight into the inner workings of the parasite.”
Dr. Rathore concluded: “New drugs are urgently needed to address the huge public health burden posed by malaria across the globe. We have recently undertaken a high-throughput screening of chemical libraries to identify compounds that can inhibit the activity of HDP. Several lead compounds were identified and have been characterized in our laboratory at VBI and subsequently validated at the Swiss Tropical Institute in Basel, Switzerland. We see considerable potential in developing these lead compounds into new drugs that can act by blocking the function of HDP in the parasite.”
Otto Folkerts, Associate Director of Technology Development at VBI, added: “Virginia Tech Intellectual Properties Inc. has filed patents that cover the intellectual property behind this discovery. We are actively seeking partners who are interested in licensing this intellectual property or jointly pursuing the development of potential malaria drug candidates that may arise from this work.”
Barry Whyte | EurekAlert!
The balancing act: An enzyme that links endocytosis to membrane recycling
07.12.2016 | National Centre for Biological Sciences
Transforming plant cells from generalists to specialists
07.12.2016 | Duke University
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
07.12.2016 | Health and Medicine
07.12.2016 | Life Sciences
07.12.2016 | Health and Medicine