Linda McLoon, PhD

Dr. McLoon received her PhD from the Department of Anatomy at the University of Illinois Medical Center, followed by postdoctoral studies with Dr. Ray Lund at the University of Washington and Medical University of South Carolina. She is a tenured Professor in the Department of Ophthalmology and Visual Neurosciences. She studies pharmacologic approaches to the treatment of eye movement disorders in children, specifically strabismus and nystagmus. She is focused on the cell biology and muscle stem cell populations within the muscles that move the eyes in the orbit, the extraocular muscles, to understand their sparing in diseases such as Duchenne muscular dystrophy and what goes awry in eye movement disorders. Recently she has added an interest in sex differences in retinal function and how this relates to neuropsychiatric disease

• Member of the Editorial Boards of Scientific Reports, Investigative Ophthalmology and Visual Science, and the Journal of the American Association for Pediatric Ophthalmology and Strabismus (JAPPOS)
• Scientific Review Committee, Fight for Sight, 2011-present
• Honorary Member (one of 6 so honored), American Association for Pediatric Ophthalmology and Strabismus, 2012-present
• Elected to Board of Trustees, Association for Research in Vision and Ophthalmology, 2011-2016
• Gold Fellow, Association for Research in Vision and Ophthalmology, 2009-present
• Lew Wasserman Mid-Career Merit Award, Research to Prevent Blindness, 2005-06
• American Society of Ophthalmic Plastic and Reconstructive Surgery Research Award for the most outstanding research published in the journal in 2002.

Research Summary/Interests

My laboratory focuses on understanding the potential mechanisms for two types of eye movement disorders: strabismus and nystagmus. Untreated these result in decreased visual acuity. Both involve the ocular motor system and the specialized skeletal muscles that move the eye, the extraocular muscles (EOM). We focus on the ability of retrogradely transported neurotrophic factors to alter the function and structure of the ocular motor system with the goal of developing a permanent therapeutic approach for these movement disorders. We have used RNAseq data to identify potential new therapeutic targets for development of treatments.

A second focus is the study of the muscle stem cell populations in the EOM that cause their differential sparing in degenerative disorders such as muscular dystrophy and amyotrophic lateral sclerosis. We have identified a specific stem cell, expressing Pitx2, which we have implicated in this differential sparing. Further work will focus on using these stem cells to prevent limb muscle degeneration in these currently untreatable diseases.

Finally, we have started a new project looking at the electroretinogram (ERG) in various mouse models of disease. Our recent studies show a significant difference in ERG characteristics in a mouse model of schizophrenia compared to controls, suggesting a specific method by which differences in the brain can be measured in the retina.

Research interests:

• Development of pharmacologic treatments for strabismus and infantile nystagmus syndrome
• Extraocular muscle cell biology
• Sparing of the extraocular muscles in muscular dystrophies
• Molecular control of extraocular muscle properties and how these are affected in strabismus and nystagmus
• Sex differences in the electroretinogram

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Rudell JC, Fleuriet J, Mustari MJ, McLoon LK. Childhood onset strabismus: a neurotrophic factor hypothesis. Invited review. PMID: 33872122. J. Binocul. Vis. Ocul. Motil. 2021;Apr 19:1-6.

Hampe CS, Wesley J, Lund TC, Orchard PJ, Polgreen LE, Eisengart JB, McLoon LK, Cureoglu S, Schachern P, McIvor RS. Mucopolysaccharidosis type I: Current treatments, limitations, and prospects for improvement. PMID: 33572941. Biomolecules. 2021;Jan 29;11(2):189.

Fleuriet J, Willoughby CL, Kueppers RB, Mustari MJ, McLoon LK. Eye alignment changes caused by sustained GDNF treatment of an extraocular muscle in infant non-human primates. PMC7368047. Sci. Rep. 2020;10:11927.

Rudell JC, Stager DR, Felius J, McLoon LK. Morphological differences in inferior oblique muscles from subjects with over-elevation in adduction.PMC7415317. Invest. Ophthalmol. Vis. Sci. 2020;61(6):33.

Torres Jimenez N, Lines J, Kueppers RB, Rankila A,Wei H, Kofuji P, Coyle J, Miller RF, McLoon LK. Electroretinographic abnormalities and sex differences detected with mesopic adaptation in a mouse model of schizophrenia: A and B wave analysis. Investigative Ophthalmology and Visual Science. 2020 Feb 7;61(2):16. https://www.ncbi.nlm.nih.gov/pubmed/32053730

Moghimi P*, Torres Jimenez N*, McLoon LK, Netoff TI, Lee MS, MacDonald III, A, Miller RG. Electroretinographic evidence of altered retinal function in schizophrenia. Schizophrenia Research. 2019 Oct 12. pii: S0920-9964(19)30414-1 *: co-first author. https://www.ncbi.nlm.nih.gov/pubmed/31615740

Verma M, Asakura Y, Murakonda BSR, Pengo T, Latroche C, Chazaud B, McLoon LK, Asakura A 2018, 'Muscle satellite cell cross-talk with a vascular niche maintains quiescence via VEGF and notch signaling. Cell Stem Cell. 2018;23:530-543.e9. https://doi.org/10.1016/j.stem.2018.09.007

Olson RM, Mokhtarzadeh A, McLoon LK, Harrison AR. Effects of repeated eyelid injections with botulinum toxin A on innervation of treated muscles in patients with blepharospasm. Current Eye Research. 2019;44:257-263. https://doi.org/10.1080/02713683.2018.1543707

Fleuriet J, McLoon LK. Visualizing neuronal adaptation over time after treatment of strabismus. Investigative Ophthalmology and Visual Science. 2018;59:5022-5024. https://doi.org/10.1167/iovs.18-25651

Fitzpatrick KR, Cucak A, McLoon LK. Changing muscle function with sustained glial derived neurotrophic factor treatment of rabbit extraocular muscle. PLoS One. 2018;13,e0202861. https://doi.org/10.1371/journal.pone.0202861

McLoon LK, Vicente A, Fitzpatrick KR, Lindström M, Pedrosa Domellöf F. Composition, architecture, and functional implications of the connective tissue network of the extraocular muscles. Investigative Ophthalmology and Visual Science. 2018;59:322-329. https://doi.org/10.1167/iovs.17-23003

Hebert SL, Fitzpatrick KR, McConnell SA, Cucak A, Yuan C, McLoon LK. Effects of retinoic acid signaling on extraocular muscle myogenic precursor cells in vitro. Experimental Cell Research. 2017;361:101-111. https://doi.org/10.1016/j.yexcr.2017.10.007

Verma, M, Asakura, Y, Murakonda, BSR, Pengo, T, Latroche, C, Chazaud, B, McLoon, LK & Asakura, A 2018, 'Muscle Satellite Cell Cross-Talk with a Vascular Niche Maintains Quiescence via VEGF and Notch Signaling' Cell Stem Cell, vol. 23, no. 4, pp. 530-543.e9. https://doi.org/10.1016/j.stem.2018.09.007

Fleuriet, J & McLoon, LK 2018, 'Visualizing neuronal adaptation over time after treatment of strabismus' Investigative Ophthalmology and Visual Science, vol. 59, no. 12, pp. 5022-5024. https://doi.org/10.1167/iovs.18-25651

Fitzpatrick, KR, Cucak, A & McLoon, LK 2018, 'Changing muscle function with sustained glial derived neurotrophic factor treatment of rabbit extraocular muscle' PLoS One, vol. 13, no. 8, e0202861. https://doi.org/10.1371/journal.pone.0202861

McLoon, LK, Vicente, A, Fitzpatrick, KR, Lindström, M & Pedrosa Domellöf, F 2018, 'Composition, architecture, and functional implications of the connective tissue network of the extraocular muscles' Investigative Ophthalmology and Visual Science, vol. 59, no. 1, pp. 322-329. https://doi.org/10.1167/iovs.17-23003

Olson, RM, Mokhtarzadeh, A, McLoon, LK & Harrison, AR 2019, 'Effects of Repeated Eyelid Injections with Botulinum Toxin A on Innervation of Treated Muscles in Patients with Blepharospasm' Current Eye Research, vol. 44, no. 3, pp. 257-263. https://doi.org/10.1080/02713683.2018.1543707

Hebert, SL, Fitzpatrick, KR, McConnell, SA, Cucak, A, Yuan, C & McLoon, LK 2017, 'Effects of retinoic acid signaling on extraocular muscle myogenic precursor cells in vitro' Experimental Cell Research, vol. 361, no. 1, pp. 101-111. https://doi.org/10.1016/j.yexcr.2017.10.007

McLoon, LK, Christiansen, SP, Ghose, GM, Das, VE & Mustari, MJ 2016, 'Improvement of Eye Alignment in Adult Strabismic Monkeys by Sustained IGF-1 Treatment' Investigative ophthalmology & visual science, vol. 57, no. 14, pp. 6070-6078. https://doi.org/10.1167/iovs.16-19739

Nelson, KR, Stevens, SM & McLoon, LK 2016, 'Prolongation of relaxation time in extraocular muscles with brain derived neurotrophic factor in adult rabbit' Investigative Ophthalmology and Visual Science, vol. 57, no. 13, pp. 5834-5842. https://doi.org/10.1167/iovs.16-19679

Yuan, C, Bothun, ED, Hardten, DR, Tolar, J & McLoon, LK 2016, 'A novel explanation of corneal clouding in a bone marrow transplant-treated patient with Hurler syndrome' Experimental Eye Research, vol. 148, pp. 83-89. https://doi.org/10.1016/j.exer.2016.05.022

McLoon, LK, Willoughby, CL, Anderson, JS, Bothun, ED, Stager, D, Felius, J, Lee, H & Gottlob, I 2016, 'Abnormally small neuromuscular junctions in the extraocular muscles from subjects with idiopathic nystagmus and nystagmus associated with albinism' Investigative Ophthalmology and Visual Science, vol. 57, no. 4, pp. 1912-1920. https://doi.org/10.1167/iovs.16-19129