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In search of . . . treatments for retinal diseases: Hemant Khanna, PhD

July 12, 2011

On Tuesdays, the Daily Voice features a first-person narrative from a researcher explaining the science behind a recent grant, and the inspiration or impetus behind becoming a scientist at UMass Medical School. If you know of a researcher you’d like to see profiled, send an email to UMMScommunications@umassmed.edu


Name: Hemant Khanna, PhD, assistant professor of ophthalmology 

Project names and amounts: 

X-linked Retinitis Pigmentosa
, National Eye Institute; three years, $864,486 
Molecular Mechanism of pathogenesis and possible treatment strategies for X-linked retinal degenerative diseases, Foundation Fighting Blindness; five years, $225,000 
Midwest Eye Banks and Transplantation Center; two years, $30,000

Hemant_Khanna 

 
Inherited diseases of the retina are a major cause of untreatable blindness worldwide. The retina harbors our photosensory neurons, called photoreceptors, which account for more than 65 percent of all cell types. Photoreceptors develop distinct membranous structures called inner segment (IS) and light-sensitive outer segment (OS). The OS develops as a coin-stack shaped structure of membranous discs loaded with proteins necessary to carry out the visual cycle. During the lifetime, the OS periodically sheds their distal discs and new discs have to be continuously added at the base. This process requires transport of proteins and lipids from the IS to the OS. Research in my laboratory focuses on understanding how the transport of proteins in photoreceptors modulates the formation and function of OS. We specifically focus on delineating the function of three retinal disease proteins: CEP290 (centrosomal protein of 290 kilo Daltons), RPGR (retinitis pigmentosa GTPase regulator) and RP2 (retinitis pigmentosa 2), which are involved in various aspects of transport cascades of photoreceptors. 

Inherited forms of retinal degenerative diseases affect one in 3,000 people worldwide. These diseases range from diabetic retinopathy, childhood onset blindness (Leber congenital amaurosis) and early adulthood disease (such as retinitis pigmentosa) to blindness over the age of 65 (age-related macular degeneration). The majority of these diseases occur due to different degree of effect on the transport of proteins. The goal of our research is to reveal novel insights into how protein transport pathways regulate the formation and function of photoreceptors. As the next step in accomplishing our objective, we have identified a new protein, RKIP (Raf-1 Kinase Inhibitory protein), which interacts with CEP290 and negatively regulates transport functions in photoreceptors. Our studies provide an opportunity to not only delineate the role of negative regulators of transport processes in photoreceptors but also explore the possibility of down regulating the function of RKIP as a treatment strategy for CEP290-associated blindness. 

I have always been curious about science and discovery but my real interest in science developed during my high school molecular biology and genetics classes. I then followed my interests in molecular and cellular biology and biochemistry of neuronal development and function. 

The scientific environment at UMass Medical School is exceptional. I am impressed with the high quality of science, mentorship and collaborative spirit of UMMS faculty and students. This was a major driving force for my move from University of Michigan to UMMS in July 2010. 

The most exciting aspect of my job is constant challenges with difficult yet interesting problems of science. I am also looking forward to the follow up work of our research that has the potential to turn into real treatments for human disorders.