Cell compaction is not required for the development of gradient refractive index profiles in the embryonic chick lens

Wang, Kehao; Hoshino, Masato; Uesugi, Kentaro; Yagi, Naoto; Young, Robert D.; Frost, Bethany E.; Regini, Justyn Wiktor; Quantock, Andrew J.; Pierscionek, Barbara K.

doi:10.1016/j.exer.2020.108112

Cited by 8 publications

(4 citation statements)

References 52 publications

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“…Optical parameters of the ocular samples were analyzed using X-ray phase tomography based on the X-ray Talbot interferometry at beamline BL20B2 in SPring-8. 32 – 35 , 43 The X-ray beam was fine-tuned to 25 keV by a Si(111) double-crystal monochromator and passed through two transmission gratings, phase grating (G1) made of Ni and absorption grating (G2) made of Au, with respective pattern thicknesses of 4.35 µm and 110 µm, a pitch of 4.8 µm, and a pattern size area of 50 × 50 mm 2 . Moiré fringe patterns generated by passage of the X-ray beam through the sample, G1, and G2 were detected by a visible-light conversion type X-ray imaging detector.…”

Section: Methodsmentioning

confidence: 99%

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Oxysterol Compounds in Mouse Mutant αA- and αB-Crystallin Lenses Can Improve the Optical Properties of the Lens

Wang

Hoshino

Uesugi

et al. 2022

Invest. Ophthalmol. Vis. Sci.

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Purpose To investigate how cataract-linked mutations affect the gradient refractive index (GRIN) and lens opacification in mouse lenses and whether there is any effect on the optics of the lens from treatment with an oxysterol compound. Methods A total of 35 mice including wild-type and knock-in mutants ( Cryaa -R49C and Cryab -R120G) were used in these experiments: 26 mice were treated with topical VP1-001, an oxysterol, in one eye and vehicle in the other, and nine mice were untreated controls. Slit lamp biomicroscopy was used to analyze the lens in live animals and to provide apparent cataract grades. Refractive index in the lenses of 64 unfixed whole mouse eyes was calculated from measurements with X-ray phase tomography based on X-ray Talbot interferometry with a synchrotron radiation source. Results Heterozygous Cryaa -R49C lenses had slightly irregularly shaped contours in the center of the GRIN and distinct disturbances of the gradient index at the anterior and posterior poles. Contours near the lens surface were denser in homozygous Cryab -R120G lenses. Treatment with topical VP1-001, an oxysterol, showed an improvement in refractive index profiles in 61% of lenses and this was supported by a reduction in apparent lens opacity grade by 1.0 in 46% of live mice. Conclusions These results indicate that α-crystallin mutations alter the refractive index gradient of mouse lenses in distinct ways and suggest that topical treatment with VP1-001 may improve lens transparency and refractive index contours in some lenses with mutations.

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Section: Methodsmentioning

confidence: 99%

“…A refractive increment applicable to proteins (0.18 mL/g) was used to calculate the refractive index of each lens, which positively correlates to protein concentration. 32 , 43 , 44 …”

Section: Methodsmentioning

confidence: 99%

Oxysterol Compounds in Mouse Mutant αA- and αB-Crystallin Lenses Can Improve the Optical Properties of the Lens

Wang

Hoshino

Uesugi

et al. 2022

Invest. Ophthalmol. Vis. Sci.

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“…Distinguishing the shapes of individual lens cells in vivo can be challenging, making it difficult to determine the degree, location and time course of fibre cell compaction. Some researchers have even suggested that compaction may not be involved in lens growth [ 13 , 14 ]. To determine whether cellular compaction is a feature of lens development, we devised a block-face imaging technique that allowed us to visualize the size and shape of cells located in the various strata of the lens.…”

Section: Introductionmentioning

confidence: 99%

The effect of fibre cell remodelling on the power and optical quality of the lens

Rodriguez,

Tan,

Šikić

et al. 2023

J. R. Soc. Interface.

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Vertebrate eye lenses are uniquely adapted to form a refractive index gradient (GRIN) for improved acuity, and to grow slowly in size despite constant cell proliferation. The mechanisms behind these adaptations remain poorly understood. We hypothesize that cell compaction contributes to both. To test this notion, we examined the relationship between lens size and shape, refractive characteristics and the cross-sectional areas of constituent fibre cells in mice of different ages. We developed a block-face imaging method to visualize cellular cross sections and found that the cross-sectional areas of fibre cells rose and then decreased over time, with the most significant reduction occurring in denucleating cells in the adult lens cortex, followed by cells in the embryonic nucleus. These findings help reconcile differences between the predictions of lens growth models and empirical data. Biomechanical simulations suggested that compressive forces generated from continuous deposition of fibre cells could contribute to cellular compaction. However, optical measurements revealed that the GRIN did not mirror the pattern of cellular compaction, implying that compaction alone cannot account for GRIN formation and that additional mechanisms are likely to be involved.

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“…139,353 In regards to the lens, it is important to note that the compaction of fiber cells does not contribute to the refractive capabilities of the tissue. 418 As we experience, the human eye is adept at light transmission, refraction, and image generation. Light is refracted at four points in the human eye, upon the entrance and exit of both the cornea and lens.…”

Section: Light Refractionmentioning

confidence: 99%

Illuminating assembly dynamics regulating short-range order optics in extremely long-lived proteins

Bergman

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To those that feel they need to follow a path -you don'tLast, but most importantly, I want to thank my partner, Jenna Marie Kremer, for all her love and support over the years. She believed in myself more than I ever could and without her, none of this would have been possible. From the very first moment we met, she encouraged and supported me. After my acceptance into the PhD program at Northeastern University, she made the decision to move across the country with me -and proved how sometimes the best plans are the ones we do not make ourselves. There have been many challenges since, both expected and very unexpected, but we have faced them together. Those who have obtained a PhD undoubtedly know that it not only contains trials of intelligence, but also those of spirit. The resilience needed to finish a dissertation, both the research and the writing, is more than I would have ever predicted.Jenna has been my pillar the entire time; I survived the trials of spirit, the difficulties of research, with her to listen, comfort, challenge, and encourage, every step of the way. She makes me want to strive for the best I can, in every aspect of life, and I have accomplished more than I expected during my time as a graduate student, and it is with much thanks to her.

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Cell compaction is not required for the development of gradient refractive index profiles in the embryonic chick lens

Cited by 8 publications

References 52 publications

Oxysterol Compounds in Mouse Mutant αA- and αB-Crystallin Lenses Can Improve the Optical Properties of the Lens

Oxysterol Compounds in Mouse Mutant αA- and αB-Crystallin Lenses Can Improve the Optical Properties of the Lens

The effect of fibre cell remodelling on the power and optical quality of the lens

Illuminating assembly dynamics regulating short-range order optics in extremely long-lived proteins

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