Role of trace elements in senile cataract

Srivastava, Vinay Kumar; Varshney, N.K.; Pandey, DJ

doi:10.1111/j.1755-3768.1992.tb04898.x

Cited by 49 publications

(34 citation statements)

References 9 publications

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“…On the contrary, Zn levels in senile cataractous lenses were found to be elevated in some studies [28,29]. It was suggested that the increased Zn levels may be harmful for the lens deteriorating the permeability of the membrane by oxidation of sulfhydryls or by causing a rise in the metallothionein level [29]. It was showed that the levels of Zn in diabetic senile cataracts were significantly increased when compared to the senile cataracts [18].…”

Section: Discussionmentioning

confidence: 93%

“…In an animal study, those rats that were fed a low-Zn diet developed cataractogenesis [27]. On the contrary, Zn levels in senile cataractous lenses were found to be elevated in some studies [28,29]. It was suggested that the increased Zn levels may be harmful for the lens deteriorating the permeability of the membrane by oxidation of sulfhydryls or by causing a rise in the metallothionein level [29].…”

Section: Discussionmentioning

confidence: 95%

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The Evaluation of the Oxidative Stress Parameters in Nondiabetic and Diabetic Senile Cataract Patients

Yıldırım

Yildirim

Uçgun

et al. 2008

Biol Trace Elem Res

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The aim of the present study was to evaluate the copper (Cu), zinc (Zn), malondialdehyde (MDA), glutathione (GSH), and advanced oxidation protein products (AOPP) levels and superoxide dismutase (SOD) activities in diabetic senile cataract. Ten patients with diabetic senile cataract and ten patients with nondiabetic senile cataract (control group) were included in this study. AOPP, MDA, and GSH levels and SOD activity were measured by a spectrophotometric method. Serum, lens Cu, and Zn levels were measured by an atomic absorption spectrophotometric method. Both the lens and serum Zn and Cu levels between the two groups were not significantly different (p > 0.05). GSH, AOPP, and MDA levels and the SOD activities in the diabetic senile cataract group were significantly increased as compared to the control group (p < 0.05). Oxidative stress is one of the major factors which may lead to the early cataract formation. Oxidative events are of great importance in diabetic complications and, particularly in the lens, may have a role in the pathogenesis of cataract associated with diabetes mellitus as exhibited in this study.

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Section: Discussionmentioning

confidence: 93%

Section: Discussionmentioning

confidence: 95%

The Evaluation of the Oxidative Stress Parameters in Nondiabetic and Diabetic Senile Cataract Patients

Yıldırım

Yildirim

Uçgun

et al. 2008

Biol Trace Elem Res

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“…27,[35][36][37] Zinc is one of the most abundant metal ions known to play significant catalytic and structural roles in many proteins. 38 We reported that of the many divalent metal ions zinc ions produce the most significant changes in conformation and chaperone function of a-crystallin.…”

Section: Discussionmentioning

confidence: 99%

Stabilization of oligomeric structure of α‐crystallin by Zn⁺² through intersubunit bridging

Karmakar

Das

2010

Biopolymers

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α-Crystallin, the major protein of mammalian eye lens, is a member of the small heat shock protein family and is a molecular chaperone. We previously reported that its molecular chaperone function as well as stability increased in presence of Zn+². Despite the effect of Zn+² on the structure and function of α-crystallin, evidence for direct interaction between them remained elusive. We now present the MALDI mass spectrometric data that shows direct evidence of Zn+² binding to recombinant αA- and αB-crystallin. The binding stoichiometry was over three Zn+² per subunit of α-crystallin at zinc/protein molar ratio of 20. Observation of multiple Zn+² binding is consistent with the large increase in thermodynamic stability. Sequence-based analysis of αA- and αB-crystallin predicted both proteins to be nonzinc binding proteins. Our dynamic light scattering data shows that Zn+² stabilizes the oligomeric structure of α-crystallin by bridging neighboring subunits in multiple centers. Despite the low affinity binding, the intersubunit bridging by multiple Zn+² makes the oligomer so stable that oligomer breakdown does not occur even at 6M urea. The subunit bridging has been supported by our FRET data that showed absence of subunit exchange in presence of zinc. MALDI data also showed that the interaction of α-crystallin with Zn+² is quite different from other bivalent metal ions. Bound Zn+² could be easily removed by dialysis of the complex. The relevance of such weak interaction on the stability of the oligomeric structure of α-crystallin and its function in the eye lens has been discussed.

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“…Previous studies have shown that lens α-crystallins bind Cu(II) and prevent the formation of Cu(II)-mediated reactive oxygen species [71–73]. Mini-αA chaperone indeed functions like an antioxidant by preventing Cu(II)-mediated oxidation of ascorbic acid [74].…”

Section: Antioxidant Action Of Mini-αa-chaperonementioning

confidence: 99%

Alpha-crystallin-derived peptides as therapeutic chaperones

Raju

Santhoshkumar

Sharma

2016

Biochimica et Biophysica Acta (BBA) - General Subjects

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Background The demonstration of chaperone-like activity in peptides (mini-chaperones) derived from α-crystallin’s chaperone region has generated significant interest in exploring the therapeutic potential of peptide chaperones in diseases of protein aggregation. Recent studies in experimental animals show that mini-chaperones could reach intended targets and alter the disease phenotype. Although mini-chaperones show potential benefits against protein aggregation diseases, they do tend to form aggregates on storage. There is thus a need to fine-tune peptide chaperones to increase their solubility, pharmacokinetics and biological efficacy. Scope of Review This review summarizes the properties and the potential therapeutic roles of mini-chaperones in protein aggregation diseases and highlights some of the refinements needed to increase the stability and biological efficacy of mini-chaperones while maintaining or enhancing their chaperone-like activity against precipitation of unfolding proteins. Major conclusions Mini-chaperones suppress the aggregation of proteins, block amyloid fibril formation, stabilize mutant proteins, sequester metal ions and exhibit antiapoptotic properties. Much work must be done to fine-tune mini-chaperones and increase their stability and biological efficacy. Peptide chaperones could have a great therapeutic value in diseases associated with protein aggregation and apoptosis. General significance Accumulation of misfolded proteins is a primary cause for many age-related diseases, including cataract, macular degeneration and various neurological diseases. Stabilization of native proteins is a logical therapeutic approach for such diseases. Mini-chaperones, with their inherent antiaggregation and antiapoptotic properties, may represent an effective therapeutic molecule to prevent the cascade of protein conformational disorders. Future studies will further uncover the therapeutic potential of mini-chaperones.

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Role of trace elements in senile cataract

Abstract: The contents of copper, zinc and protein were determined in cortex and nucleus sections of cortical and nuclear cataracts. The results show that copper and zinc content increased in both types of cataracts, although more in the cortex than nucleus sections of the cataractous lenses.

Cited by 49 publications

References 9 publications

The Evaluation of the Oxidative Stress Parameters in Nondiabetic and Diabetic Senile Cataract Patients

The Evaluation of the Oxidative Stress Parameters in Nondiabetic and Diabetic Senile Cataract Patients

Stabilization of oligomeric structure of α‐crystallin by Zn⁺² through intersubunit bridging

Alpha-crystallin-derived peptides as therapeutic chaperones

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Role of trace elements in senile cataract

Abstract: The contents of copper, zinc and protein were determined in cortex and nucleus sections of cortical and nuclear cataracts. The results show that copper and zinc content increased in both types of cataracts, although more in the cortex than nucleus sections of the cataractous lenses.

Cited by 49 publications

References 9 publications

The Evaluation of the Oxidative Stress Parameters in Nondiabetic and Diabetic Senile Cataract Patients

The Evaluation of the Oxidative Stress Parameters in Nondiabetic and Diabetic Senile Cataract Patients

Stabilization of oligomeric structure of α‐crystallin by Zn+2 through intersubunit bridging

Alpha-crystallin-derived peptides as therapeutic chaperones

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Stabilization of oligomeric structure of α‐crystallin by Zn⁺² through intersubunit bridging