Spatial distributions of glutathione and its endogenous conjugates in normal bovine lens and a model of lens aging

Nye-Wood, Mitchell G.; Spraggins, Jeffrey M.; Caprioli, Richard M.; Schey, Kevin L.; Donaldson, Paul J.; Grey, Angus C.

doi:10.1016/j.exer.2016.11.008

Cited by 33 publications

(33 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The mature form and the truncated form are most abundant in the outer cortex, but their signal extends into the inner cortical region. Interestingly, the glutathionylated form is intense in the very outer cortical region, where the glutathione levels are highest . βA3‐crystallin ( m/z 25 152) has a similar distribution as the mature βB2‐crystallin ( m/z 23 122).…”

Section: Resultsmentioning

confidence: 97%

MALDI imaging mass spectrometry of β‐ and γ‐crystallins in the ocular lens

et al. 2019

Self Cite

View full text Add to dashboard Cite

Lens crystallin proteins make up 90% of expressed proteins in the ocular lens and are primarily responsible for maintaining lens transparency and establishing the gradient of refractive index necessary for proper focusing of images onto the retina. Agerelated modifications to lens crystallins have been linked to insolubilization and cataractogenesis in human lenses. Matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) has been shown to provide spatial maps of such age-related modifications. Previous work demonstrated that, under standard protein IMS conditions, α-crystallin signals dominated the mass spectrum and agerelated modifications to α-crystallins could be mapped. In the current study, a new sample preparation method was optimized to allow imaging of βand γ-crystallins in ocular lens tissue. Acquired images showed that γ-crystallins were localized predominately in the lens nucleus whereas β-crystallins were primarily localized to the lens cortex. Age-related modifications such as truncation, acetylation, and carbamylation were identified and spatially mapped. Protein identifications were determined by top-down proteomics analysis of lens proteins extracted from tissue sections and analyzed by LC-MS/MS with electron transfer dissociation. This new sample preparation method combined with the standard method allows the major lens crystallins to be mapped by MALDI IMS.

show abstract

Section: Resultsmentioning

confidence: 97%

MALDI imaging mass spectrometry of β‐ and γ‐crystallins in the ocular lens

et al. 2019

Self Cite

View full text Add to dashboard Cite

show abstract

“…Different alterations in the refractive properties and transparency of the lens are produced during the development of presbyopia and cataract. Although it is not well understood how lens cellular structure and function initiate changes in refraction and transparency, a common underlying mechanism in the pathology of cortical and nuclear cataract can be attributed to the failure of the microcirculation system to regulate cell volume in the lens cortex, or deliver antioxidants [ 8 ], such as the Glutathione [ 9 , 10 ], to the lens nucleus [ 11 ]. Donaldson et al [ 11 ] rigorously described the physiological optics of the crystalline lens and the development of cataract, suggesting future possible treatments based on functionality changes at the cellular level.…”

Section: Aging Of the Crystalline Lensmentioning

confidence: 99%

From Presbyopia to Cataracts: A Critical Review on Dysfunctional Lens Syndrome

Fernández¹,

Rodríguez‐Vallejo²,

Martínez³

et al. 2018

Journal of Ophthalmology

View full text Add to dashboard Cite

Dysfunctional lens syndrome (DLS) is a term coined to describe the natural aging changes in the crystalline lens. Different alterations in the refractive properties and transparency of the lens are produced during the development of presbyopia and cataract, such as changes in internal high order aberrations or an increase in ocular forward scattering, with a potentially significant impact on clinical measures, including visual acuity and contrast sensitivity. Objective technologies have emerged to solve the limits of current methods for the grading of the lens aging, which have been linked to the DLS term. However, there is still not a gold standard or evidence-based clinical guidelines around these new technologies despite multiple research studies have correlated their results with conventional methods such as visual acuity or the lens opacification system (LOCS), with more scientific background around the ocular scattering index (OSI) and Scheimpflug densitometry. In either case, DLS is not a new evidence-based concept that leads to new knowledge about crystalline lens aging but it is a nomenclature change of two existing terms, presbyopia and cataracts. Therefore, this term should be used with caution in the scientific peer-reviewed literature.

show abstract

“…Imaging mass spectrometry (IMS) allows the spatial characterization of thousands of proteins and other small molecules in a tissue in situ during a single experiment [60] (for review, see [61]). This technique has been utilized in investigations of the cornea [62], retinal lipids [63, 64], and lens GSH [65, 66], lipids [67–69], UV-filters [70], and proteins [71, 72]. To our knowledge, our study is the first to use IMS in a microphthalmia mouse model.…”

Section: Discussionmentioning

confidence: 99%

Gclc deletion in surface-ectoderm tissues induces microphthalmia

Thompson

Chen

Philippe

et al. 2019

Preprint

View full text Add to dashboard Cite

Glutamate cysteine ligase catalytic subunit (Gclc) is the catalytic subunit for the glutamate-cysteine ligase (Gcl) enzyme. Gcl catalyzes the rate limiting step in glutathione (GSH) synthesis. Gclc is highly expressed in the developing eye. To define the regulatory role of Gclc in eye development, we developed a novel, Le-Cre transgene-driven, Gclc knockout mouse model. Gclc f/f /Le-Cre Tg/mice present with deformation of the retina, cornea, iris, and lens, consistent with a microphthalmia phenotype. Controlling for the microphthalmia phenotype of Gclc wt/wt /Le-Cre Tg/mice revealed that Gclc f/f /Le-Cre Tg/mice have a more severe microphthalmia phenotype. Thus, the loss of Gclc expression exacerbates the microphthalmia phenotype in Le-Cre mice.Gclc f/f /Le-Cre Tg/eyes present with reduced retinal and lens epithelium proliferation and increased lens cell death. Imaging mass spectrometry of ocular tissues revealed changes in the intensity and distribution of several lipid species and proteins in the retina and corneas of Gclc f/f /Le-Cre Tg/eyes. Lastly, using splice-blocking morpholinos and CRISPR/Cas9, we created two gclc knockdown zebrafish models, both of which display a microphthalmia phenotype. Combined, the mouse and zebrafish results indicate that, in chordates, Gclc has a conserved role in regulating eye development. In summary, these novel animal models are useful tools for elucidating the mechanisms involved in microphthalmia development.≈ 11% of the cases [1]. Currently, there is no cure for the severe loss of vision associated with microphthalmia. While surgical treatments exist, they only address the cosmetic abnormalities associated with microphthalmia [15]. However, recent research demonstrating the efficacy of nonsense suppression (inhibiting the effect of a nonsense mutation by pharmacologically increasing the likelihood of a near cognate aminoacyl-tRNA substitution) to rescue lens development when administered postnatally in a Pax6-deficient mouse model has provided hope that treatments for microphthalmia can be developed [16]. Clearly, a more complete understanding of the mechanisms regulating lens development should accelerate the discovery of preventative strategies and/or novel therapeutic treatments for microphthalmia. Glutathione (GSH), an intracellular antioxidant, is highly abundant in the eye, with concentrations of 20mM or more occurring in the lens cortex and epithelium [17, 18]. It is important for physiological detoxification of electrophiles and oxidants in the lens cortex and epithelium [19]. Through these functions, GSH maintains lens clarity and, as such, a decline in GSH levels is associated with cataract development [20, 21]. GSH biosynthesis involves a two-step enzymatic process [22] involving glutamate-cysteine ligase (GCL) followed by glutathione synthase (GSS). GCL, the rate limiting step in GSH synthesis, comprises a catalytic subunit (GCLC) and a modifier subunit (GCLM). Impaired GCLC or GCLM function limits GSH synthesis and reduces intracellular GSH concentrations. Th...

show abstract

Spatial distributions of glutathione and its endogenous conjugates in normal bovine lens and a model of lens aging

Cited by 33 publications

References 48 publications

MALDI imaging mass spectrometry of β‐ and γ‐crystallins in the ocular lens

MALDI imaging mass spectrometry of β‐ and γ‐crystallins in the ocular lens

From Presbyopia to Cataracts: A Critical Review on Dysfunctional Lens Syndrome

Gclc deletion in surface-ectoderm tissues induces microphthalmia

Contact Info

Product

Resources

About