PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Under the right conditions, peptide blocks HIV infection at multiple points along the way

Researchers: Findings about innate peptide may offer new avenue of research for combating HIV, other viruses

2012-07-25
(Press-News.org) Human defensins, aptly named antimicrobial peptides, are made in immune system cells and epithelial cells (such as skin cells and cells that line the gut). One of these peptides, human neutrophil peptide 1, under certain circumstances hinders HIV infection, but exactly how it works remains unclear.

HIV entry into mature T-helper cells (cells essential to the immune system) proceeds by attachment of the virus to specific targets on T-helper cells, uptake of the virus, fusion of its envelope with the cell membranes, and release of the virus into the cells. In a forthcoming Journal of Biological Chemistry Paper of the Week, Gregory Melikyan at Emory University and colleagues investigated the ability of human neutrophil peptide 1 to impede each step of this process.

Using model cell lines, Melikyan's group showed that human neutrophil peptide 1 effectively prevented HIV entry into cells in multiple ways. First, human neutrophil peptide 1 reduced the number of specific targets on the cells available for HIV attachment. Second, this defensin also bound to specific targets on both the HIV envelope and the cells, preventing early and late stages of HIV-cell fusion. Finally, human neutrophil peptide 1 prevented HIV uptake into the cells without compromising the general ability of the cells to engulf other molecules.

While human neutrophil peptide 1 hinders HIV entry into cells under these lab conditions, it does not do so as effectively in the presence of serum -- meaning that it may not be as successful at blocking HIV in our bodies. But Melikyan's team showed that human neutrophil peptide 1 remained attached to its specific targets in the presence of serum, despite its reduced efficacy. Their work suggests that the structure of human neutrophil peptide 1 is important for its anti-HIV activity, and they propose that serum may interfere with the ability of this defensin to form complexes, reducing its ability to block HIV.

"Our work provides new insights into the ability of defensins to recognize and neutralize diverse pathogens, including HIV," Melikyan says. This research reveals that human neutrophil peptide 1 can bind various viral and cellular targets and that a previously unappreciated feature is essential for its anti-HIV activity, possibly its propensity to form large complexes, Melikyan explains.

The team's findings suggest a new avenue of research for combatting HIV and viruses that infiltrate cells in a similar manner.

INFORMATION:

From the article: "Multifaceted mechanisms of HIV-1 entry inhibition by human alpha-defensin" by Lusine H. Demirkhanyan, Mariana Marin, Sergi Padilla-Parra, Changyou Zhan, Kosuke Miyauchi, Maikha Jean-Baptiste, Gennadiy Novitskiy, Wuyuan Lu, and Gregory B. Melikyan (to be published in the Aug. 17 issue of the Journal of Biological Chemistry and currently online as a Paper in Press at http://www.jbc.org/content/early/2012/06/25/jbc.M112.375949.full.pdf)

Corresponding author: Gregory B. Melikyan, Department of Pediatrics Infectious Diseases, Emory University in Atlanta, GA, USA; email: gmeliki@emory.edu

Written by Danielle Gutierrez

END



ELSE PRESS RELEASES FROM THIS DATE:

How chronic obstructive pulmonary disease increases risk of lung cancer

2012-07-25
In addition to the well-known risk factor of smoking, chronic obstructive pulmonary disease (COPD) increases lung cancer risk. A University of Colorado Cancer Center study published in the journal Cancer Prevention Research details one novel mechanism of this risk: long-term oxygen depletion stimulates signals that promote tumor growth. In addition, this early study – performed in animal models – shows that tumors fueled by these COPD-induced signals may be especially susceptible to prevention or perhaps even treatment with drugs that turn off these same signals, namely ...

Active forest management to reduce fire could help protect northern spotted owl

2012-07-25
CORVALLIS, Ore. – The northern spotted owl, a threatened species in the Pacific Northwest, would actually benefit in the long run from active management of the forest lands that form its primary habitat and are increasingly vulnerable to stand-replacing fire, researchers conclude in a recent study. Whatever short-term drawbacks there may be from logging, thinning, or other fuel reduction activities in areas with high fire risk would be more than offset by improved forest health and fire-resistance characteristics, the scientists said, which allow more spotted owl habitat ...

Feces fossils yield new insights into ancient diets and 'thrifty genes'

2012-07-25
Scientists have long speculated that high diabetes rates among Native Americans may have roots in the evolutionary past. "Thrifty" genes that helped ancient hunter-gatherers store fat for survival during famine may contribute to diabetes in modern times of plenty. But a new analysis of fossil feces from an Arizona cave suggests that the evolution of thrifty genes had little to do with famine and much more to do with the nature of the ancient feast. The research, reported in the August issue of Current Anthropology, shows that prehistoric hunter-gatherers in the Southwest ...

Pulling CO2 from air vital, say researchers

2012-07-25
Emerging techniques to pull carbon dioxide from the air and store it away to stabilize the climate may become increasingly important as the planet tips into a state of potentially dangerous warming, researchers from Columbia University's Earth Institute argue in a paper out this week. The upfront costs of directly taking carbon out of the air will likely be expensive, but such technology may well become cheaper as it develops and becomes more widely used, and cost should not be a deterrent to developing such a potentially valuable tool, the authors said. The techniques ...

Same adaptations evolve across different insects

2012-07-25
The famous biologist Stephen J. Gould once asked: If we rerun the tape of life, would the outcome of evolution be the same? For years, scientists have questioned whether evolution is predictable, or whether chance events make such predictability unlikely. A study published online July 23 in the Proceedings of the National Academy of Sciences finds that in the case of insects that developed resistance to a powerful plant toxin, the same adaptations have occurred independently, in separate species in different places and times. The paper examines 18 insect species across ...

New probe provides vital assist in brain cancer surgery

2012-07-25
A new probe developed collaboratively at Norris Cotton Cancer Center and Dartmouth College's Thayer School of Engineering uses an innovative fluorescence-reading technology to help brain surgeons distinguish cancerous tissue from normal tissue. The probe tool, now already in use at the Cancer Center for brain surgery, may one day be used for surgeries for a variety of cancers. Performing surgery to remove a brain tumor requires surgeons to walk a very fine line. If they leave tumor tissue behind, the tumor is likely to regrow; if they cut out too much normal tissue, they ...

Yoga reduces stress; now it's known why

2012-07-25
Six months ago, researchers at UCLA published a study that showed using a specific type of yoga to engage in a brief, simple daily meditation reduced the stress levels of people who care for those stricken by Alzheimer's and dementia. Now they know why. As previously reported, practicing a certain form of chanting yogic meditation for just 12 minutes daily for eight weeks led to a reduction in the biological mechanisms responsible for an increase in the immune system's inflammation response. Inflammation, if constantly activated, can contribute to a multitude of chronic ...

Human papillomavirus types do not replace others after large-scale vaccination

2012-07-25
Vaccines against human papillomavirus (HPV) are now recommended by the Centers for Disease Control and Prevention for both teenage boys and girls. The vaccine protects against the two most common types of the virus that cause cervical cancer: HPV 16 and 18. Is there a chance that the increased number of people vaccinated might result in an increase of other types of HPV that cause cancer? A UNC-led international team of scientists studied this question in a group of 2228 Kenyan men as a "nested" trial in a larger trial. Their first paper in the Journal of Infectious ...

To understand childhood obesity, researchers look to inactive, fat rats

2012-07-25
BETHESDA, Md. (July 24, 2012)—Childhood obesity has nearly tripled in the past three decades, and by 2009, 17 percent of those 2-19 years of age were classified as obese. If actions against childhood obesity do not take place it is likely that today's children could be the first generation in over a century to experience a decline in life expectancy due to the epidemic of childhood obesity which leads to complications in later life. While little is known about how inactivity and obesity lead to undesirable side effects such as diabetes, cardiovascular disease and some cancers, ...

How a common fungus knows when to attack

2012-07-25
BOSTON—The opportunistic fungal pathogen Candida albicans inconspicuously lives in our bodies until it senses that we are weak, when it quickly adapts to go on the offensive. The fungus, known for causing yeast and other minor infections, also causes a sometimes-fatal infection known as candidemia in immunocompromised patients. An in vivo study, published in mBio, demonstrates how C. albicans can distinguish between a healthy and an unhealthy host and alter its physiology to attack. "The ability of the fungus to sense the immune status of its host may be key to its ability ...

LAST 30 PRESS RELEASES:

Forest trees and microbes choreograph their hunt for a ‘balanced diet’ under elevated CO2

Beyond health: The political effects of infectious disease outbreaks

For tastier and hardier citrus, researchers built a tool for probing plant metabolism

Stay hydrated: New sensor knows when you need a drink

Quantum internet meets space-time in this new ingenious idea

Soil erosion in mountain environments accelerated by agro-pastoral activities for 3,800 years

Optogenetic platform illuminates new antiviral strategies

A new theory explaining oscillations in tunnel magnetoresistance (TMR)

Early antibiotics alter immune function in infants

With the second grant to therapy

Research center developing digital twins for manufacturing

Colombia’s biofortified rice has untapped potential to improve nutrition. And consumers want it

Study shows pregnancy can significantly worsen risk of serious brain injury in women with arteriovenous malformations

Mapping important infrastructure could aid emergency response after hurricanes

Nighttime pistachio snacking may reshape gut microbiome in prediabetic adults

Friendship promotes neural and behavioral similarity

Neural pathway for nicotine withdrawal symptoms

How your DNA reveals your true age with astonishing accuracy

First electronic–photonic quantum chip created in commercial foundry

High-performance scientific computing can compute molecule ground-state energy

Cryo-electron microscopy – Reaction cycle of an enzyme for CO2 fixation decoded

Feeling more extroverted? Study finds you may have learned how to handle daily stress better

Kindness counts—even to a five-day-old baby

Endocrine Society guideline calls for increased screening for common cause of high blood pressure

Macromolecular gene delivery systems: advancing non-viral therapeutics with synthetic and natural polymers

Study finds political instability, environmental conditions, and social inequality accelerate aging

New insights into malaria: Proteins in the blood can reveal the severity of the disease

Delayed hypertension diagnosis and its association with cardiovascular treatment and outcomes

GLP-1 receptor agonists in idiopathic intracranial hypertension

Integrating diet and physical activity when prescribing GLP-1s—lifestyle factors remain crucial

[Press-News.org] Under the right conditions, peptide blocks HIV infection at multiple points along the way
Researchers: Findings about innate peptide may offer new avenue of research for combating HIV, other viruses