News

Under the Lens: Link Between Macular Degeneration and Retinitis Pigmentosa

By: 

Laurie Fickman
Retinitis pigmentosa and macular degeneration are both genetic disorders that can cause loss of vision and neither has a cure.
Retinitis pigmentosa and macular degeneration are both genetic disorders that can cause loss of vision and neither has a cure.
Married for 44 years, Muna Naash, left, and Muayyad Al Ubaidi are partners in the lab, too, where they are examining the protein peripherin2 and its link to blinding eye diseases.
Married for 44 years, Muna Naash, left, and Muayyad Al Ubaidi are partners in the lab, too, where they are examining the protein peripherin2 and its link to blinding eye diseases.

UH Research Team Examines Eye Disease with $2.5 Million Award

 

Four words you never want to hear from the eye doctor are retinitis pigmentosa and macular degeneration. Both are genetic disorders that can cause loss of vision and neither has a cure. A team of biomedical researchers at the University of Houston's Cullen College of Engineering is now tackling both eye diseases by exploring a protein in the retina that links them: peripherin2 (prph2).

“Mutations in peripherin 2 are associated with a variety of retinal degenerative diseases, including retinitis pigmentosa, cone-rod dystrophy and multiple forms of macular dystrophy,” said Muna Naash, John S. Dunn Endowed Professor of biomedical engineering and principal investigator. “Peripherin2 mutations can also cause secondary defects in adjacent tissues including the retinal pigment epithelium and choroid, which hampers the development of therapeutics for these diseases.”

When healthy, prph2 is essential for the structure and function of the outer segments of the retinal photoreceptors. The two types of photoreceptors involved in sight are rods, which work at low levels of light, and cones, which are used to see color. Damaged rods cause retinitis pigmentosa; degeneration of cones causes macular degeneration.

“We are focused on advancing current knowledge on the role of peripherin2 in outer segment rim and disc formation, and in understanding the pathogenic mechanisms of associated diseases,” said Muayyad Al Ubaidi, professor of biomedical engineering and project partner. The work is funded by a $2.5 million grant from the National Eye Institute.

“Periphen2 is an incredibly exciting protein to study and understand because, depending on which part of the protein has a mutation, it can cause different phenotypes in each patient,” said Al-Ubaidi.

Prph2 does not always work alone. It has a partner, a photoreceptor-specific gene called ROM1 (rod outer segment membrane protein 1). The two proteins combine in different ratios, subsequently causing different diseases.

In prior research, Naash found that by changing the ratio of prph2 and ROM1 she could convert cases of the more dangerous macular degeneration to the less severe retinitis pigmentosa.

“We found we could convert the pattern dystrophy or macular degeneration phenotype to retinitis pigmentosa phenotype by modulating ROM1 level,” said Naash. This suggests that elimination of the mutant protein will be a pre-requisite for any curative therapeutic strategy.

Naash and Al-Ubaidi will examine how different mutations in prph2 lead to different disease phenotypes; what contributes to variability among patients carrying the same mutation; what role ROM1 plays in these events; and, how to shift prph2-associated severe phenotypes to milder ones.

Click here for more information on Naash and Al Ubaidi’s 44-year marriage in life and in the lab.

Faculty: 

Department/Academic Programs: 

Tag: 

Related News Stories

New Technology Could Improve LASIK Surgery, Eye Disease Detection

Dr. Kirill Larin, University of Houston professor of biomedical engineering, is creating new technology to measure the elasticity of the cornea.

UH Professor to Create Ultrafast 3D Clinical Imaging System

LASIK eye surgery – a laser reshaping of the cornea to improve vision – is one of the most popular elective surgeries in the United States, and a University of Houston professor of biomedical engineering intends to improve upon it by giving surgeons more information about the cornea before they begin.  

Nearing a Treatment for Farsightedness

Kirill Larin, professor of biomedical engineering, has received $3 million from the National Eye Institute to create a new technology capable of precise noninvasive and depth-resolved quantitative measurements of the lens mechanical properties in a clinical setting.

UH Professor Developing New Technology to Detect Lens Elasticity

A biomedical researcher at the University of Houston's Cullen College of Engineering is developing new technology that will measure the stiffness of the lens in the eye, which is likely associated with presbyopia, or farsightedness, the inevitable and age-related loss of the ability to focus on nearby objects.