Featured Research

from universities, journals, and other organizations

45 years on: How serotonin makes schistosome parasites move

Date:
January 16, 2014
Source:
Public Library of Science
Summary:
Schistosoma mansoni and its close relatives are parasitic flatworms that affect millions worldwide and kill an estimated 250,000 people a year. A study identifies a new part of the molecular pathway that controls parasite movement. And because coordinated movement is essential for the schistosome life cycle in its human host, this protein is a promising new drug target.

This is the expression of a serotonin receptor (bright green) in the Schistosoma mansoni nervous system. The muscles of the oral sucker and the muscular lining of the digestive tract appear in red.
Credit: Nidhi Sharma, Institute of Parasitology, McGill University

Schistosoma mansoni and its close relatives are parasitic flatworms that affect millions worldwide and kill an estimated 250,000 people a year. A study published on January 16 in PLOS Pathogens identifies a new part of the molecular pathway that controls parasite movement. And because coordinated movement is essential for the schistosome life cycle in its human host, this protein is a promising new drug target.

Related Articles


"We know that many anti-parasitic drugs act on the worm's nervous system," says Paula Ribeiro from McGill University in Montreal, Canada, the lead author of the new study, "and have known for over 40 years that the neurotransmitter serotonin controls schistosome movement. As schistosomes are becoming resistant to the only effective drug we have, it was time to go after their serotonin receptor."

Serotonin is a signaling molecule that is used across species, including man, mouse, and worm. It exerts its function through specific serotonin receptors that span the membranes of nerve cells. When these receptors pick-up serotonin the nerve cells become activated. In some cases, this activation in turn activates muscle cells, eventually resulting in movement.

As nobody had discovered a schistosome serotonin receptor yet, Ribeiro and colleagues started by a computer (or "in silico") search for DNA sequences from S. mansoni that looked similar to known serotonin receptor genes. They found a candidate and verified that the corresponding protein, which they called Schistosoma mansoni 5HTR, or Sm5HTR, is indeed a serotonin receptor. When cells that have the protein embedded in their membrane get exposed to serotonin on the outside, the scientists could measure a typical response inside these cells.

The scientists then went on to examine where in the parasite Sm5HTR is present, and report that the receptor is found widely on nerve cells in both larvae and adult worms. When they used various ways to interfere with receptor function, they found that larval and adult schistosomes were greatly inhibited in their movement. For example, when schistosome larvae are bathed in serotonin, they become twitchy and hyperactive. Larvae which have many fewer receptors don't show that response. And adult worms with fewer receptors move much less than those with normal numbers.

These studies suggest that even if schistosomes have additional serotonin receptors (and the in silico analysis suggests that there is at least one other), Sm5HTR is a major mediator of serotonin-controlled worm movement.

The authors conclude "We know from previous studies that locomotion is critical for survival of the parasite and that drug-induced paralysis is an effective way of clearing worm infections. Having identified Sm5HTR allows us to begin searching for selective receptor inhibitors that cause paralysis of the worm and may be suitable for therapeutic use."


Story Source:

The above story is based on materials provided by Public Library of Science. Note: Materials may be edited for content and length.


Journal Reference:

  1. Nicholas Patocka, Nidhi Sharma, Mohammed Rashid, Paula Ribeiro. Serotonin Signaling in Schistosoma mansoni: A Serotonin–Activated G Protein-Coupled Receptor Controls Parasite Movement. PLoS Pathogens, 2014; 10 (1): e1003878 DOI: 10.1371/journal.ppat.1003878

Cite This Page:

Public Library of Science. "45 years on: How serotonin makes schistosome parasites move." ScienceDaily. ScienceDaily, 16 January 2014. <www.sciencedaily.com/releases/2014/01/140116190313.htm>.
Public Library of Science. (2014, January 16). 45 years on: How serotonin makes schistosome parasites move. ScienceDaily. Retrieved December 19, 2014 from www.sciencedaily.com/releases/2014/01/140116190313.htm
Public Library of Science. "45 years on: How serotonin makes schistosome parasites move." ScienceDaily. www.sciencedaily.com/releases/2014/01/140116190313.htm (accessed December 19, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Friday, December 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Navy Unveils Robot Fish

Navy Unveils Robot Fish

Reuters - Light News Video Online (Dec. 18, 2014) The U.S. Navy unveils an underwater device that mimics the movement of a fish. Tara Cleary reports. Video provided by Reuters
Powered by NewsLook.com
Kids Die While Under Protective Services

Kids Die While Under Protective Services

AP (Dec. 18, 2014) As part of a six-month investigation of child maltreatment deaths, the AP found that hundreds of deaths from horrific abuse and neglect could have been prevented. AP's Haven Daley reports. (Dec. 18) Video provided by AP
Powered by NewsLook.com
When You Lose Weight, This Is Where The Fat Goes

When You Lose Weight, This Is Where The Fat Goes

Newsy (Dec. 17, 2014) Can fat disappear into thin air? New research finds that during weight loss, over 80 percent of a person's fat molecules escape through the lungs. Video provided by Newsy
Powered by NewsLook.com
The Hottest Food Trends for 2015

The Hottest Food Trends for 2015

Buzz60 (Dec. 17, 2014) Urbanspoon predicts whicg food trends will dominate the culinary scene in 2015. Mara Montalbano (@maramontalbano) has the story. Video provided by Buzz60
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins