Medindia LOGIN REGISTER
Medindia
Advertisement

Leprosy Pathogen Eludes Vital Vitamin D-Dependent Immune Response

by Nancy Needhima on January 31, 2012 at 11:03 PM
Leprosy Pathogen Eludes Vital Vitamin D-Dependent Immune Response

The pathogen responsible for leprosy has an unusual ability to evade the human immune system by restraining the antimicrobial responses crucial to our defenses, reveals a new study.

In one of the first laboratory studies of its kind, researchers discovered that the leprosy pathogen Mycobacterium leprae was able to reduce and evade immune activity that is dependent on vitamin D, a natural hormone that plays an essential role in the body's fight against infections.

Advertisement

The pathogen manipulated micro-RNAs, tiny molecules made of ribonucleic acids that carry information and that help regulate genes to direct cell activity, including immune system defenses.

Micro-RNAs are short RNAs that do not code information for proteins, which carry out all cell activity; rather, they bind to the RNAs that do code for proteins and block them.
Advertisement

The new findings demonstrated how an infectious disease pathogen like M. leprae can use micro-RNAs to impact the immune system's fight response.

"We may find that these tiny micro-RNAs can be exploited by pathogens to weaken our immune response," said the study's first author, Dr. Philip T. Liu, an assistant professor of medicine at the Orthopaedic Hospital Research Center and in the department of dermatology at the David Geffen School of Medicine at UCLA.

"By better understanding how pathogens can escape our immune cells, we can design more effective therapies to boost our immune responses to these difficult to treat infections like leprosy."

Leprosy, one of the world's oldest known diseases, is a chronic infectious disease that affects the skin, the peripheral nerves, the upper respiratory tract and the eyes and can lead to disfigurement of the hands, face and feet.

For the study, researchers compared the micro-RNAs in human skin lesions from two types of leprosy: tuberloid leprosy, a milder infection that is more easily contained, and lepromatous leprosy, which is more serious and causes widespread infection throughout the body.

In the lab, the scientists identified 13 micro-RNAs that differed between the two types of leprosy. The micro-RNAs that were found to be more common in lepromatous leprosy seemed to target the genes important for directing key immune system cells, including macrophages and T cells.

The team found that a particular micro-RNA, hsa-mir-21, inhibited the gene activity of the vitamin D-dependent immune pathway used to help fight infection. When researchers neutralized the activity of hsa-mir-21 in macrophages, the cells were able to kill the bacteria again.

"The leprosy pathogen was able to effectively evade the host's immune response by regulating critical immune system genes," said senior investigator Dr. Robert Modlin, UCLA's Klein Professor of Dermatology and chief of dermatology at the Geffen School of Medicine.

"It's like having the enemy sending a decoy message to your combat troops and telling them to lower their weapons."

To test the significance of this micro-RNA with other infectious diseases, the researchers also introduced hsa-mir-21 to human macrophages that were then infected with tuberculosis in the lab. Researchers found that the micro-RNA similarly blocked the ability of the macrophages to kill the bacteria.

In addition, the team showed that this micro-RNA was found in human immune cells only 18 hours after the onset of leprosy infection. The presence of the micro-RNA so early in the infection suggests it might play a role in actual disease development, the researchers said.

"We may find that a combination of vitamin D supplementation with a genetically targeted therapy could provide an optimal treatment approach to leprosy and possibly other chronic infectious diseases," said Modlin, who also serves as vice chair for cutaneous medicine and dermatological research at UCLA and is a distinguished professor of medicine and of microbiology, immunology and molecular genetics.

The study has been published in the online edition of the journal Nature Medicine.

Source: ANI
Font : A-A+

Advertisement

Advertisement
Advertisement

Recommended Readings

Latest Research News

Confronting the Painful Realities of Racial Bias in Health
Painful realities of racial discrimination and bias are increasingly acknowledged as harmful to the well-being.
Intricate Dance of Flaxseed, Gut Microbiome, and Breast Cancer Genes
Role of flaxseed in the relationship between gut microorganisms and mammary gland microRNAs has been uncovered by a new study.
MRNA Therapy's Promise for Chronic and Acute Liver Disease
New mRNA stem cell therapy, akin to COVID-19 vaccine tech, shows potential against chronic and acute liver diseases.
Could Light Therapy Be a Breakthrough for Alzheimer's?
Light therapy enhances sleep and psycho-behavioral symptoms in Alzheimer's patients with minimal side effects.
Does Twice Daily Stimulation Enhance Alzheimer's Mental Functions?
Electrical stimulation improves Alzheimer's patients' cognitive function and correlates with restored cortical plasticity.
View All
This site uses cookies to deliver our services.By using our site, you acknowledge that you have read and understand our Cookie Policy, Privacy Policy, and our Terms of Use  Ok, Got it. Close
×

Leprosy Pathogen Eludes Vital Vitamin D-Dependent Immune Response Personalised Printable Document (PDF)

Please complete this form and we'll send you a personalised information that is requested

You may use this for your own reference or forward it to your friends.

Please use the information prudently. If you are not a medical doctor please remember to consult your healthcare provider as this information is not a substitute for professional advice.

Name *

Email Address *

Country *

Areas of Interests