Lens Proteins Research Articles

Glycation and drug binding by serum albumin.

Accumulation of glycation products in patients with hyperglycaemic conditions can lead to their reaction with the proteins in the human system such as serum albumin, haemoglobin, insulin, plasma lipoproteins, lens proteins and collagen among others which have important biological functions. Therefore, it is important to understand if glycation of these proteins affects their normal action not only qualitatively, but also importantly quantitatively. Glycation of human serum albumin can easily be carried out over period of weeks and its drug transportability may be examined, in addition to characterisation of the amadori products. A combination of ultrasensitive isothermal titration calorimetry, differential scanning calorimetry, spectroscopy and chromatography provides structure-property-energetics correlations which are important to obtain mechanistic aspects of drug recognition, conformation of the protein, and role of amadori products under conditions of glycation. The role of advance glycation end products is important in recognition of antidiabetic drugs. Further, the extent of glycation of the protein and its implication on drug transportability investigated by direct calorimetric methods enables unravelling mechanistic insights into role of functionality on drug molecules in the binding process, and hinderance in the recognition process, if any, as a result of glycation. It is possible that the drug binding ability of the protein under glycation conditions may not be adversely affected, or may even lead to strengthened ability. Rigorous studies on such systems with diverse functionality on the drug molecules is required which is essential in deriving guidelines for improvements in the existing drugs or in the synthesis of new molecular entities directed towards addressing diabetic conditions.

Silicone Bubble Giving Double Trouble

Cataract formation following silicone oil (SO) implantation is a common entity following retinal intervention due to lens touch. Other causes of lens opacity are light toxicity, oxidation of lens protein, and use of intra-ocular gas in managing posterior segment pathology. We presented a case of secondary open-angle glaucoma in the right eye post SO infusion for retinal detachment, which eventually led to SO cataract after 10 months. The best corrected visual acuity was 1/60 in the right eye. Thereafter, with conservative management of high intra-ocular pressure, combined SO removal with phacoemulsification cataract surgery was done, which retrieved a visual acuity of 3/60 and an intra.ocular pressure of 12 mmHg with monotherapy.

Identification of new antioxidant drugs in a human in vitro model of ageing‐associated cataract

Aims/Purpose: Cataracts are a significant cause of global blindness, impacting millions (10.8 million patients), and their prevalence is expected to increase over the coming decades as our populations age. Oxidative stress disrupts ROS (reactive oxygen species) balance in lens fibre cells, leading to lens protein degradation and accumulation, developing age‐related cataracts. The lens has protective mechanisms, including high GSH levels and antioxidant enzymes like catalase, safeguarding lens health. While surgery is currently the only effective treatment, non‐invasive drug‐based approaches show potential by reducing risks and complications. With its potent antioxidant activity, resveratrol may protect lens cells and slow cataract development. However, the limited ability of resveratrol to penetrate lens tissue restricts its direct effects. Therefore, designing new molecules to improve ADME (absorption, distribution, metabolism and excretion) properties is required.Methods: In this study, we used an in vitro model of cataracts by inducing oxidative stress and cell death by adding hydrogen peroxide (H2O2) and luperox to lens epithelial cells to evaluate the protective effects of new molecules against oxidative stress and compared them with resveratrol. Our study assessed the cell viability, intracellular ROS level, mitochondrial function, catalase activity and GSH/GSSH level.Results: These compounds preserved cell viability, reduced ROS levels, maintained mitochondrial function and enhanced catalase activity and GSH levels in lens epithelial cells exposed to H2O2. The novel drugs, CAB‐C1 and CAB‐C2, demonstrated beneficial effects on cellular health.Conclusions: Developing drugs for cataract treatment enables early intervention, particularly for individuals with mild or moderate cataracts who may not require surgery yet. Such advancements might improve patients' quality of life and have implications for ocular science and age‐related eye diseases.

Molecular Insights into the Inhibitory Role of α-Crystallin against γD-Crystallin Aggregation.

Cataracts, a major cause of global blindness, contribute significantly to the overall prevalence of blindness. The opacification of the lens, resulting in cataract formation, primarily occurs due to the aggregation of crystallin proteins within the eye lens. Despite the high concentration of these crystallins, they remarkably maintain the lens transparency and refractive index. α-Crystallins (α-crys), acting as chaperones, play a crucial role in preventing crystallin aggregation, although the exact molecular mechanism remains uncertain. In this study, we employed a combination of molecular docking, all-atom molecular dynamics simulations, and advanced free energy calculations to investigate the interaction between γD-crystallin (γD-crys), a major structural protein of the eye lens, and α-crystallin proteins. Our findings demonstrate that α-crys exhibits an enhanced affinity for the NTD2 and CTD4 regions of γD-crys. The NTD2 and CTD4 regions form the interface between the N-terminal domain (NTD) and the C-terminal domain (CTD) of the γD-crys protein. By binding to the interface region between the NTD and CTD of the protein, α-crys effectively inhibits the formation of domain-swapped aggregates and mitigates protein aggregation. Analysis of the Markov state models using molecular dynamics trajectories confirms that minimum free energy conformations correspond to the binding of the α-crystallin domain (ACD) of α-crys to NTD2 and CTD4 that form the interdomain interface.

Aβ in the Lens of the Eye: A Noninvasively Detectable Early Biomarker of Alzheimer’s Disease β‐Amyloidopathy in Humans and Transgenic Mouse Model

AbstractBackgroundAmyloid‐ß (Aß) accumulation in brain is an early hallmark of Alzheimer’s disease (AD). We discovered Aß deposition, ß‐amyloidopathy, and colocalizing supranuclear cataracts (SNC) in lenses from people with AD (Goldstein LE et al., Lancet, 2003) and Down syndrome (DS; Moncaster JA et al., PLoS One, 2010), but not other neurodegenerative diseases or normal aging. These findings spurred development of an investigational drug‐device lens Aß eye scanner (Sapphire II, Cognoptix) that combines an Aß‐binding fluorescent ligand (Aftobetin) and specialized laser scanning ophthalmoscope for noninvasive measurement of lens Aß (FDA Breakthrough Device, 2021). Early clinical results indicate that lens Aß is an ideal biomarker for early AD detection. Here, we investigated Aß accumulation and amyloidopathy in lens and brain.MethodTg2576 transgenic (Tg+) mice express Swedish mutant human amyloid precursor protein (hAPP‐Swe), human Aß (hAß), ß‐amyloidopathy, and cognitive deficits (Hsiao et al., Science, 1996). Non‐transgenic (Tg–) littermates were used as controls. Lenses were examined by ex vivo lens stereomicroscopy. Brains and lenses were analyzed by Aß immunohistochemistry, amyloid histopathology, anti‐Aß immunogold electron microscopy, tryptic digest mass spectrometry, anti‐hAß ELISA/immunoblotting. Quasi‐elastic light scattering hAß‐lens protein aggregation analysis.ResultTg2576 Tg+ mice, but not Tg– controls, age‐dependently express hAPP, accumulate hAß, and develop hAß molecular pathology in the lens and exhibit age‐dependent Aß supranuclear opacification that recapitulates lens pathology and SNC phenotype expression in human AD and DS. We detected hAß in conditioned medium from Tg+ but not Tg– lens explant cultures. hAß potently promotes mouse lens protein aggregation in vitro.ConclusionThese results support mechanistic (genotype‐phenotype) linkage between age‐dependent Aß pathology and AD‐related phenotypes in lens and brain. Collectively, our findings identify Aß pathology as the shared molecular etiology of age‐dependent supranuclear cataracts associated with two human diseases (AD, DS) and homologous murine cataracts in the Tg2576 transgenic mouse model of AD. These results represent the first evidence of AD‐related Aß pathology outside the brain and support lens Aß as an optically‐accessible biomarker for early detection and longitudinal monitoring of AD.

Aβ in the Lens of the Eye: A Noninvasively Detectable Early Biomarker of Alzheimer’s Disease β‐Amyloidopathy in Humans and Transgenic Mouse Model

AbstractBackgroundAmyloid‐β (Aβ) accumulation in brain is an early hallmark of Alzheimer’s disease (AD). We discovered Aβ deposition, β‐amyloidopathy, and colocalizing supranuclear cataracts (SNC) in lenses from people with AD (Goldstein LE et al., Lancet, 2003) and Down syndrome (DS; Moncaster JA et al., PLoS One, 2010), but not other neurodegenerative diseases or normal aging. These findings spurred development of an investigational drug‐device lens Aβ eye scanner (Sapphire II, Cognoptix) that combines an Aβ‐binding fluorescent ligand (Aftobetin) and specialized laser scanning ophthalmoscope for noninvasive measurement of lens Aβ (FDA Breakthrough Device, 2021). Early clinical results indicate that lens Aβ is an ideal biomarker for early AD detection. Here, we investigated Aβ accumulation and amyloidopathy in lens and brain.MethodTg2576 transgenic (Tg+) mice express Swedish mutant human amyloid precursor protein (hAPP‐Swe), human Aβ (hAβ), β‐amyloidopathy, and cognitive deficits (Hsiao et al., Science, 1996). Non‐transgenic (Tg–) littermates were used as controls. Lenses were examined by ex vivo lens stereomicroscopy. Brains and lenses were analyzed by Aβ immunohistochemistry, amyloid histopathology, anti‐Aβ immunogold electron microscopy, tryptic digest mass spectrometry, anti‐hAβ ELISA/immunoblotting. Quasi‐elastic light scattering hAβ‐lens protein aggregation analysis.ResultTg2576 Tg+ mice, but not Tg– controls, age‐dependently express hAPP, accumulate hAβ, and develop hAβ molecular pathology in the lens and exhibit age‐dependent Aβ supranuclear opacification that recapitulates lens pathology and SNC phenotype expression in human AD and DS. We detected hAβ in conditioned medium from Tg+ but not Tg– lens explant cultures. hAβ potently promotes mouse lens protein aggregation in vitro.ConclusionThese results support mechanistic (genotype‐phenotype) linkage between age‐dependent Aβ pathology and AD‐related phenotypes in lens and brain. Collectively, our findings identify Aβ pathology as the shared molecular etiology of age‐dependent supranuclear cataracts associated with two human diseases (AD, DS) and homologous murine cataracts in the Tg2576 transgenic mouse model of AD. These results represent the first evidence of AD‐related Aβ pathology outside the brain and support lens Aβ as an optically‐accessible biomarker for early detection and longitudinal monitoring of AD.

Baicalein improves Na2SeO3 induced cataract by enhancing the antioxidant capacity of juvenile Sprague Dawley Rat

Ethnopharmacological relevanceBaicalein (BAI) is the crucial flavonoid component in Scutellaria baicalensis Georgi, possessing biological functions such as anti-oxidant, anti-apoptotic, and anti-inflammatory. However, there is limited intensive pharmacological and mechanistic research on the therapeutic effects of BAI for cataract treatment. Aim of the studyThis study aimed to investigate the effects and mechanisms of BAI on Na2SeO3-induced cataract in juvenile rats. Materials and methodsThe cataract model was established by a single subcutaneous injection of 3.46 mg/kg Na2SeO3 on the back of 10-day-old rats. The BAI (25 mg/kg, 50 mg/kg, 100 mg/kg) was administered to the 8-day-old rats and continued until they reached 30 days of age, and the opacity of the lens was observed using a slit lamp microscope every 3 days. Pathological changes in the lens were observed using hematoxylin-eosin (HE) staining to investigate the effects of BAI on Na2SeO3-induced cataract in rats. The levels of antioxidant substances in rat serum and the lens, as well as the levels of soluble and insoluble proteins in rat lens, were measured by the reagent kit. Furthermore, the mechanism of BAI on Na2SeO3-induced cataract rats was analyzed by network pharmacology, molecular docking, and Western blot. ResultsBAI significantly increased the content of soluble proteins in the lens, mitigated the dense opacity of rat lens and reduced the damage to lens epithelial cells, reduced the levels of malondialdehyde (MDA) in rat serum and lens, increased the levels of total superoxide dismutase (T-SOD) and Glutathione peroxidase (GSH-PX). The improvement effects of BAI on Na2SeO3-induced cataract may related to the mitogen-activated protein kinase (MAPK) and the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling pathways. ConclusionIn conclusion, this study demonstrated that BAI could mitigate the dense opacity of rat lens in Na2SeO3-induced cataract rats, which may be achieved through the MAPK signaling pathway and the PI3K/AKT signaling pathway.

ATF4 May Be Essential for Adaption of the Ocular Lens to Its Avascular Environment.

The late embryonic mouse lens requires the transcription factor ATF4 for its survival although the underlying mechanisms were unknown. Here, RNAseq analysis revealed that E16.5 Atf4 null mouse lenses downregulate the mRNA levels of lens epithelial markers as well as known markers of late lens fiber cell differentiation. However, a comparison of this list of differentially expressed genes (DEGs) with other known transcriptional regulators of lens development indicated that ATF4 expression is not directly controlled by the previously described lens gene regulatory network. Pathway analysis revealed that the Atf4 DEG list was enriched in numerous genes involved in nutrient transport, amino acid biosynthesis, and tRNA charging. These changes in gene expression likely result in the observed reductions in lens free amino acid and glutathione levels, which would result in the observed low levels of extractable lens protein, finally leading to perinatal lens disintegration. These data demonstrate that ATF4, via its function in the integrated stress response, is likely to play a crucial role in mediating the adaption of the lens to the avascularity needed to maintain lens transparency.

Topical ocular application of aggrelyte-2A reduces lens stiffness in mice.

Presbyopia is the progressive loss of the ability of the lens to focus on nearby objects due to its increased stiffness. It occurs in the mid-40s and continues to worsen until the mid-60s. The age-associated increase in protein cross-linking in the lens leads to protein aggregation and water insolubility, especially in the nuclear region, contributing to lens stiffness. This study reports the development of aggrelyte-2A (methyl S-acetyl-N-(3,3-dimethylbutanoyl) cysteinate, a derivative of our previously reported aggrelyte-2) for reversing the stiffness of aged lenses. Aggrelyte-2A showed minimal toxicity in cultured mouse lens epithelial cells (up to 2000 µM) and human lens epithelial cells (up to 250 µM). Lenses from aged mice (age: 24-25 months) treated with 1 mM aggrelyte-2A for 24h, and human lenses (age: 47-67 years) treated with 250 µM aggrelyte-2A for 48h showed 11-14% reductions in stiffness, accompanied by an increase in acetyllysine in lens proteins, and free-thiols in the lens. Topical application of aggrelyte-2A (40 mM, 5 µl twice daily for 4 weeks) on mouse eyes significantly reduced lens stiffness. The topical application showed no toxicity to the lens, cornea, or retina, as revealed by morphological examination, H&E staining, and optical coherence tomography. These data suggest that aggrelyte-2A could be developed as a presbyopia-reversing therapeutic.

Interaction of βL- and γ-Crystallin with Phospholipid Membrane Using Atomic Force Microscopy.

Highly concentrated lens proteins, mostly β- and γ-crystallin, are responsible for maintaining the structure and refractivity of the eye lens. However, with aging and cataract formation, β- and γ-crystallin are associated with the lens membrane or other lens proteins forming high-molecular-weight proteins, which further associate with the lens membrane, leading to light scattering and cataract development. The mechanism by which β- and γ-crystallin are associated with the lens membrane is unknown. This work aims to study the interaction of β- and γ-crystallin with the phospholipid membrane with and without cholesterol (Chol) with the overall goal of understanding the role of phospholipid and Chol in β- and γ-crystallin association with the membrane. Small unilamellar vesicles made of Chol/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (Chol/POPC) membranes with varying Chol content were prepared using the rapid solvent exchange method followed by probe tip sonication and then dispensed on freshly cleaved mica disk to prepare a supported lipid membrane. The βL- and γ-crystallin from the cortex of the bovine lens was used to investigate the time-dependent association of βL- and γ-crystallin with the membrane by obtaining the topographical images using atomic force microscopy. Our study showed that βL-crystallin formed semi-transmembrane defects, whereas γ-crystallin formed transmembrane defects on the phospholipid membrane. The size of semi-transmembrane defects increases significantly with incubation time when βL-crystallin interacts with the membrane. In contrast, no significant increase in transmembrane defect size was observed in the case of γ-crystallin. Our result shows that Chol inhibits the formation of membrane defects when βL- and γ-crystallin interact with the Chol/POPC membrane, where the degree of inhibition depends upon the amount of Chol content in the membrane. At a Chol/POPC mixing ratio of 0.3, membrane defects were observed when both βL- and γ-crystallin interacted with the membrane. However, at a Chol/POPC mixing ratio of 1, no association of γ-crystallin with the membrane was observed, which resulted in a defect-free membrane, and the severity of the membrane defect was decreased when βL-crystallin interacted with the membrane. The semi-transmembrane or transmembrane defects formed by the interaction of βL- and γ-crystallin on phospholipid membrane might be responsible for light scattering and cataract formation. However, Chol suppressed the formation of such defects in the membrane, likely maintaining lens membrane homeostasis and protecting against cataract formation.

Design and Characterization of Model Systems that Promote and Disrupt Transparency of Vertebrate Crystallins In Vitro.

Positioned within the eye, the lens supports vision by transmitting and focusing light onto the retina. As an adaptive glassy material, the lens is constituted primarily by densely-packed, polydisperse crystallin proteins that organize to resist aggregation and crystallization at high volume fractions, yet the details of how crystallins coordinate with one another to template and maintain this transparent microstructure remain unclear. The role of individual crystallin subtypes (α, β, and γ) and paired subtype compositions, including how they experience and resist crowding-induced turbidity in solution, is explored using combinations of spectrophotometry, hard-sphere simulations, and surface pressure measurements. After assaying crystallin combinations, β-crystallins emerged as a principal component in all mixtures that enabled dense fluid-like packing and short-range order necessary for transparency. These findings helped inform the design of lens-like hydrogel systems, which are used to monitor and manipulate the loss of transparency under different crowding conditions. When taken together, the findings illustrate the design and characterization of adaptive materials made from lens proteins that can be used to better understand mechanisms regulating transparency.

Dehydroalanine and dehydrobutyrine in aging and cataractous lenses reveal site-specific consequences of spontaneous protein degradation.

Protein post-translational modifications (PTMs) have been associated with aging and age-related diseases. PTMs are particularly impactful in long-lived proteins, such as those found in the ocular lens, because they accumulate with age. Two PTMs that lead to protein-protein crosslinks in aged and cataractous lenses are dehydroalanine (DHA) and dehydrobutyrine (DHB); formed from cysteine/serine and threonine residues, respectively. The purpose of this study was to quantitate DHA and DHB in human lens proteins as a function of age and cataract status. Human lenses of various ages were divided into five donor groups: transparent lenses (18-22-year-old, 48-64-year-old, and 70-93-year-old) and cataractous human lenses of two age groups (48-64-year-old lenses, and 70-93-year-old lenses) and were subjected to proteomic analysis. Relative DHA and DHB peptide levels were quantified and compared to their non-modified peptide counterparts. For most lens proteins containing DHA or DHB, higher amounts of DHA- and DHB-modified peptides were detected in aged and cataractous lenses. DHA-containing peptides were classified into three groups based on abundance changes with age and cataract: those that (1) increased only in age-related nuclear cataract (ARNC), (2) increased in aged and cataractous lenses, and (3) decreased in aged lenses and ARNC. There was no indication that DHA or DHB levels were dependent on lens region. In most donor groups, proteins with DHA and DHB were more likely to be found among urea-insoluble proteins rather than among water- or urea-soluble proteins. DHA and DHB formation may induce structural effects that make proteins less soluble in water that leads to age-related protein insolubility and possibly aggregation and light scattering.

Mitophagy in Astrocytes Is Required for the Health of Optic Nerve.

Mitochondrial dysfunction in astrocytes has been implicated in the development of various neurological disorders. Mitophagy, mitochondrial autophagy, is required for proper mitochondrial function by preventing the accumulation of damaged mitochondria. The importance of mitophagy, specifically in the astrocytes of the optic nerve (ON), has been little studied. We introduce an animal model in which two separate mutations act synergistically to produce severe ON degeneration. The first mutation is in Cryba1, which encodes βA3/A1-crystallin, a lens protein also expressed in astrocytes, where it regulates lysosomal pH. The second mutation is in Bckdk, which encodes branched-chain ketoacid dehydrogenase kinase, which is ubiquitously expressed in the mitochondrial matrix and involved in the catabolism of the branched-chain amino acids. BCKDK is essential for mitochondrial function and the amelioration of oxidative stress. Neither of the mutations in isolation has a significant effect on the ON, but animals homozygous for both mutations (DM) exhibit very serious ON degeneration. ON astrocytes from these double-mutant (DM) animals have lysosomal defects, including impaired mitophagy, and dysfunctional mitochondria. Urolithin A can rescue the mitophagy impairment in DM astrocytes and reduce ON degeneration. These data demonstrate that efficient mitophagy in astrocytes is required for ON health and functional integrity.

Некоторые биохимические изменения хрусталика в процессе старения.

The goal is to study some biochemical changes in the lens of rats and humans during aging. Materials and methods. Experiments were carried out on 25 rats. We also examined 84 patients with initial nuclear cataract. Results. diverse dynamics of the content of total lipids in the lenses of rats was revealed. There is a noticeable decrease in the content of products of oxidative modification of lipids in the lens tissue between 12 and 24 months and a slight increase in the period from 24 to 36 months. A 2-fold decrease in the content of the total protein level was revealed when comparing groups of 5 months and 36 months and an increase in total protein content with age. When comparing the parameters of oxidative degradation, cl in the lens tissue of rats and humans with age, similar indicators of dynamics were obtained. Conclusion. The data obtained indicate changes in the parameters of lipids and proteins in the lens tissue of rats during postnatal ontogenesis. The fact that there is a balance between damage and protection of proteins in the transparent lens was revealed. When comparing data on protein oxidation in the lens tissue of rats and humans with age, similar indicators were obtained. Keywords: lens, aging, biochemical changes

Binding of βL-Crystallin with Models of Animal and Human Eye Lens-Lipid Membrane.

Several discoveries show that with age and cataract formation, β-crystallin binds with the lens membrane or associates with other lens proteins, which bind with the fiber cell plasma membrane, accompanied by light scattering and cataract formation. However, how lipids (phospholipids and sphingolipids) and cholesterol (Chol) influence β-crystallin binding to the membrane is unclear. This research aims to elucidate the role of lipids and Chol in the binding of β-crystallin to the membrane and the membrane's physical properties (mobility, order, and hydrophobicity) with β-crystallin binding. We used electron paramagnetic resonance (EPR) spin-labeling methods to investigate the binding of βL-crystallin with a model of porcine lens-lipid (MPLL), model of mouse lens-lipid (MMLL), and model of human lens-lipid (MHLL) membrane with and without Chol. Our results show that βL-crystallin binds with all of the investigated membranes in a saturation manner, and the maximum parentage of the membrane surface occupied (MMSO) by βL-crystallin and the binding affinity (Ka) of βL-crystallin to the membranes followed trends: MMSO (MPLL) > MMSO (MMLL) > MMSO (MHLL) and Ka (MHLL) > Ka (MMLL) ≈ Ka (MPLL), respectively, in which the presence of Chol reduces the MMSO and Ka for all membranes. The mobility near the headgroup regions of the membranes decreases with an increase in the binding of βL-crystallin; however, the decrease is more pronounced in the MPLL and MMLL membranes than the MHLL membrane. In the MPLL and MMLL membranes, the membranes become slightly ordered near the headgroup with an increase in βL-crystallin binding compared to the MHLL membrane. The hydrophobicity near the headgroup region of the membrane increases with βL-crystallin binding; however, the increase is more pronounced in the MPLL and MMLL membranes than the MHLL membrane, indicating that βL-crystallin binding creates a hydrophobic barrier for the passage of polar molecules, which supports the barrier hypothesis in cataract formation. However, in the presence of Chol, there is no significant increase in hydrophobicity with βL-crystallin binding, suggesting that Chol prevents the formation of a hydrophobic barrier, possibly protecting against cataract formation.

Potential of GJA8 gene variants in predicting age-related cataract: A comparison of supervised machine learning methods.

Cataracts are the problems associated with the crystallins proteins of the eye lens. Any perturbation in the conformity of these proteins results in a cataract. Age-related cataract is the most common type among all cataracts as it accounts for almost 80% of cases of senile blindness worldwide. This research study was performed to predict the role of single nucleotide polymorphisms (SNPs) of the GJA8 gene with age-related cataracts in 718 subjects (400 age-related cataract patients and 318 healthy individuals). A comparison of supervised machine learning classification algorithm including logistic regression (LR), random forest (RF) and Artificial Neural Network (ANN) were presented to predict the age-related cataracts. The results indicated that LR is the best for predicting age-related cataracts. This successfully developed model after accounting different genetic and demographic factors to predict cataracts will help in effective disease management and decision-making medical practitioner and experts.

Targeting LGSN restores sensitivity to chemotherapy in gastric cancer stem cells by triggering pyroptosis

Gastric cancer (GC) is notoriously resistant to current therapies due to tumor heterogeneity. Cancer stem cells (CSCs) possess infinite self-renewal potential and contribute to the inherent heterogeneity of GC. Despite its crucial role in chemoresistance, the mechanism of stemness maintenance of gastric cancer stem cells (GCSCs) remains largely unknown. Here, we present evidence that lengsin, lens protein with glutamine synthetase domain (LGSN), a vital cell fate determinant, is overexpressed in GCSCs and is highly correlated with malignant progression and poor survival in GC patients. Ectopic overexpression of LGSN in GCSC-derived differentiated cells facilitated their dedifferentiation and treatment resistance by interacting with vimentin and inducing an epithelial-to-mesenchymal transition. Notably, genetic interference of LGSN effectively suppressed tumor formation by inhibiting GCSC stemness maintenance and provoking gasdermin-D-mediated pyroptosis through vimentin degradation/NLRP3 signaling. Depletion of LGSN combined with the chemo-drugs 5-fluorouracil and oxaliplatin could offer a unique and promising approach to synergistically rendering this deadly cancer eradicable in vivo. Our data place focus on the role of LGSN in GCSC regeneration and emphasize the critical importance of pyroptosis in battling GCSC.

Evaluation of cataract formation in fish exposed to environmental radiation at Chernobyl and Fukushima

Recent studies apparently finding deleterious effects of radiation exposure on cataract formation in birds and voles living near Chernobyl represent a major challenge to current radiation protection regulations. This study conducted an integrated assessment of radiation exposure on cataractogenesis using the most advanced technologies available to assess the cataract status of lenses extracted from fish caught at both Chernobyl in Ukraine and Fukushima in Japan. It was hypothesised that these novel data would reveal positive correlations between radiation dose and early indicators of cataract formation.The structure, function and optical properties of lenses were analysed from atomic to millimetre length scales. We measured the short-range order of the lens crystallin proteins using Small Angle X-Ray Scattering (SAXS) at both the SPring-8 and DIAMOND synchrotrons, the profile of the graded refractive index generated by these proteins, the epithelial cell density and organisation and finally the focal length of each lens.The results showed no evidence of a difference between the focal length, the epithelial cell densities, the refractive indices, the interference functions and the short-range order of crystallin proteins (X-ray diffraction patterns) in lens from fish exposed to different radiation doses. It could be argued that animals in the natural environment which developed cataract would be more likely, for example, to suffer predation leading to survivor bias. But the cross-length scale study presented here, by evaluating small scale molecular and cellular changes in the lens (pre-cataract formation) significantly mitigates against this issue.

The Aqueous Stem Bark Extract of Alstonia boonei Exhibits Anticataract Activity in Sprague Dawley Rat.

In Africa, Alstonia boonei is used folklorically for the management of the multitude of conditions including cataract, which accounts for 50% of cases of blindness in the region. The current study set out to probe the traditional use of the aqueous extract of Alstonia boonei stem bark (ABE) as an anticataract remedy using Sprague Dawley rat models. We investigated the probable phytochemical constituents in the extract, in vitro antioxidant potential, and its in vitro aldose reductase inhibition. For the anticataract investigations, diabetic cataract was induced using galactose in 3-week-old Sprague Dawley rats, and age-related cataract was induced by the administration of sodium selenite to 10-day-old rat pups. Cataract scores in both models were determined after treatment with 30, 100, and 300 mgkg-1 doses of ABE and 10 mlkg-1 of distilled water. Lens glutathione, total lens protein, soluble lens proteins (alpha-A) crystallin, and aquaporin 0 levels in the enucleated lens homogenates were determined. Changes in lens to body weight were also determined with histopathological analysis done on the lenses in the selenite-induced cataract model. The presence of alkaloids, tannins, flavonoids, glycosides, and triterpenoids was identified in the extract. The extract inhibited aldose reductase activity with IC50 of 92.30 μgml-1. The 30, 100, and 300 mgkg-1ABE-treated rats recorded significantly (p < 0.05) reduced cataract scores indicating a delay in cataractogenesis in galactose-induced cataract and in selenite-induced cataractogenesis as well. Markers of lens transparency such as AQP0, alpha-A crystallin, and total lens proteins and lens glutathione levels were significantly (p < 0.05) preserved. In conclusion, this study establishes the anticataract potential of the aqueous stem bark extract of Alstonia boonei in Sprague Dawley rat models.

A Novel CRYBB2 Silent Variant in Autosomal Dominant Congenital Cataracts (ADCC) in Pakistani families.

Congenital Cataract is a type of ophthalmic genetic disorder that appears at birth or in early childhood. Among 30 genes, CRYBB2 is one of the most common and a water-soluble protein of lens's that code for the βB2-crystallin. This study aimed to investigate the novel silent mutation in CRYBB2 of exon six in the Pakistani families of Autosomal Dominant Congenital Cataracts (ADCC). It is a family-based study that presents three to five-generations of two Pakistani families. Data and blood samples from the families were collected from January to August 2019 from LRBT (Layton Rahmatullah Benevolent Trust) Hospital, Mansehra, Pakistan. We only included patients >15 years old. Before enrollment in the current study, each patient obtained a thorough optical examination. Samples were moved to the molecular lab using the collection and storage method. The phenol-chloroform technique was used to extract the DNA. The technique of Sanger sequencing was used to find any potential mutation in some of the selected families. Statistical and bioinformatics analysis were carried out. By using bioinformatics tools, the novel silent mutation was identified. Heterozygous silent mutation of CRYBB2 of exon 6 (c. 495G>A) was detected by the alignment of sequences. Computational prediction program did not predict the silent mutation. This study investigated a novel important sequence variant in the beta-crystalline protein that causes autosomal dominant congenital cataract (ADCC) in Pakistani families. Thus, our study enlarges the CRYBB2 mutation spectrum and associated phenotypes to help clinical diagnosis of human genetic diseases.