Studies on the Citric Acid Cycle and its Portion of Glucose Breakdown by Calf and Bovine Lenses in vitro

Hockwin, O.; Blum, Gary N.; Körte, I.; Murata, Takao; W, Radetzki; Rast, F.

doi:10.1159/000264555

Cited by 13 publications

(5 citation statements)

References 1 publication

(1 reference statement)

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“…Lens physiology is dramatically affected by degradation of mitochondria via mitophagy regulated by BCL2-interacting protein 3-like (Bnip3l, Nix) [ 228 ] as a prerequisite of the OFZ formation [ 62 , 63 , 229 ]. Thus, the majority of the lens requires anaerobic glycolysis, while oxidative phosphorylation is limited to outer regions of the lens fiber cell compartment [ 230 , 231 ]. In addition, the posterior vitreous contains a lower concentration of oxygen compared to the anterior aqueous humor chamber [ 232 ].…”

Section: 3d-eye Organoids: Experimental Challenges and In Vitro Model...mentioning

confidence: 99%

Generation of Lens Progenitor Cells and Lentoid Bodies from Pluripotent Stem Cells: Novel Tools for Human Lens Development and Ocular Disease Etiology

Cvekl

Camerino

2022

Cells

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In vitro differentiation of human pluripotent stem cells (hPSCs) into specialized tissues and organs represents a powerful approach to gain insight into those cellular and molecular mechanisms regulating human development. Although normal embryonic eye development is a complex process, generation of ocular organoids and specific ocular tissues from pluripotent stem cells has provided invaluable insights into the formation of lineage-committed progenitor cell populations, signal transduction pathways, and self-organization principles. This review provides a comprehensive summary of recent advances in generation of adenohypophyseal, olfactory, and lens placodes, lens progenitor cells and three-dimensional (3D) primitive lenses, “lentoid bodies”, and “micro-lenses”. These cells are produced alone or “community-grown” with other ocular tissues. Lentoid bodies/micro-lenses generated from human patients carrying mutations in crystallin genes demonstrate proof-of-principle that these cells are suitable for mechanistic studies of cataractogenesis. Taken together, current and emerging advanced in vitro differentiation methods pave the road to understand molecular mechanisms of cataract formation caused by the entire spectrum of mutations in DNA-binding regulatory genes, such as PAX6, SOX2, FOXE3, MAF, PITX3, and HSF4, individual crystallins, and other genes such as BFSP1, BFSP2, EPHA2, GJA3, GJA8, LIM2, MIP, and TDRD7 represented in human cataract patients.

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Section: 3d-eye Organoids: Experimental Challenges and In Vitro Model...mentioning

confidence: 99%

Generation of Lens Progenitor Cells and Lentoid Bodies from Pluripotent Stem Cells: Novel Tools for Human Lens Development and Ocular Disease Etiology

Cvekl

Camerino

2022

Cells

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“…Aerobik glikoliz için gerekli olan sitrik asit döngüsü enzimleri sadece lensin ön kısmında bulunan epitel hücrelerinde mevcuttur. Yapılmış bir hayvan çalışmasında gösterildiği üzere, sitrik asit döngüsünün enerji verimliliği çok daha yüksek olduğu için, lensteki glikozun sadece %3'ünü kullanmasına rağ-men, lenste glikolizden sağlanan total enerjinin %20 -30 kadarını sağlar (48).…”

Section: Lens Metabolizmasıunclassified

Lens Proteinleri ve Fizyolojisi - Derleme

Alikma

Erkul

Unsal

2018

SDÜ Tıp Fakültesi Dergisi

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Vücudumuzda bulunan bazı doku ve organlar dışında genel itibari ile beslenme damar yolu ile olur. Fenestralı kılcal damarlar doku içerisine yayılarak dokunun ihtiyaç duyduğu oksijeni eritrositler, besin maddelerini de kanın serum kısmı ile taşır. Doku ihtiyacı olan metabolitleri aldıktan sonra artıklarını da yine fenestralı kılcal damarlar ve lenf damaları sayesinde geri verir. Lens vücutta kan dolaşımının aktif olarak bulunmadığı ve canlılığını koruyan nadir yapılardan bir tanesidir. Beslenmesini ve artık boşaltımını aköz hümöre bağımlı olarak gerçekleştirir. Lensin metabolizması bu yüzden özelleşmiş bir döngüye sahiptir. Vücuttaki tüm organ ve dokuların temel yapı taşı proteindir. Lens vücutta hacim başına en fazla protein olan dokulardan biridir. İçeriğindeki yüksek protein miktarı lensin ihtiyaç duyduğu yüksek kırıcılık indeksine ve refraktif indeksin oluşmasını sağlar. Aynı zamanda lensin saydamlığının korunmasında da lens proteinleri önemli görevler üstlenir. Bununla birlikte lens hücrelerinin birbiri ile madde alışverişi sağlayabilmesi için de fonksiyonlar görür. Lens hücreleri içerisindeki proteinler ise hücre şeklinin korunmasında görev yaparlar.

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“…Because of its greater efficiency, the citric acid cycle provides 20–30% of the total lens while consuming only roughly 3% of the glucose. 190,191 Although the lens can control its ion balance, maintain high-energy phosphate levels, and carry out protein synthesis in the absence of oxygen, blocking the Embden–Meyerhof pathway by exposing the lens to iodoacetate, which inhibits 3-phosphoglyceraldehyde dehydrogenase, causes ionic changes with accompanying swelling and cataracts. 192,193 Conversely, exposure of cultured lenses to oxidative stress induced by exposure to hydrogen peroxide 194 or hyperbaric oxygen 195 increases hexokinase activity and thus stimulates the pentose phosphate pathway.…”

Section: Lens Metabolismmentioning

confidence: 99%

Lens Biology and Biochemistry

Hejtmancik

Riazuddin

McGreal

et al. 2015

Progress in Molecular Biology and Translational Science

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The primary function of the lens resides in its transparency and ability to focus light on the retina. These require both that the lens cells contain high concentrations of densely packed lens crystallins to maintain a refractive index constant over distances approximating the wavelength of the light to be transmitted, and a specific arrangement of anterior epithelial cells and arcuate fiber cells lacking organelles in the nucleus to avoid blocking transmission of light. Because cells in the lens nucleus have shed their organelles, lens crystallins have to last for the lifetime of the organism, and are specifically adapted to this function. The lens crystallins comprise two major families: the βγ-crystallins are among the most stable proteins known and the α-crystallins, which have a chaperone-like function. Other proteins and metabolic activities of the lens are primarily organized to protect the crystallins from damage over time and to maintain homeostasis of the lens cells. Membrane protein channels maintain osmotic and ionic balance across the lens, while the lens cytoskeleton provides for the specific shape of the lens cells, especially the fiber cells of the nucleus. Perhaps most importantly, a large part of the metabolic activity in the lens is directed toward maintaining a reduced state, which shelters the lens crystallins and other cellular components from damage from UV light and oxidative stress. Finally, the energy requirements of the lens are met largely by glycolysis and the pentose phosphate pathway, perhaps in response to the avascular nature of the lens. Together, all these systems cooperate to maintain lens transparency over time.

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Studies on the Citric Acid Cycle and its Portion of Glucose Breakdown by Calf and Bovine Lenses in vitro

Cited by 13 publications

References 1 publication

Generation of Lens Progenitor Cells and Lentoid Bodies from Pluripotent Stem Cells: Novel Tools for Human Lens Development and Ocular Disease Etiology

Generation of Lens Progenitor Cells and Lentoid Bodies from Pluripotent Stem Cells: Novel Tools for Human Lens Development and Ocular Disease Etiology

Lens Proteinleri ve Fizyolojisi - Derleme

Lens Biology and Biochemistry

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