Evaluation of anti-oxidant treatments in an in vitro model of alkaptonuric ochronosis

Braconi, Daniela; Laschi, Marcella; Amato, Loredana; Bernardini, Giulia; Millucci, Lia; Marcolongo, Roberto; Cavallo, Giovanni; Spreafico, Adriano; Santucci, Annalisa

doi:10.1093/rheumatology/keq175

Cited by 44 publications

(58 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although the molecular mechanisms underlying alkaptonuria and especially ochronotic arthropathy have not been fully elucidated, we provided evidences suggesting an important role for oxidative stress induced by HGA auto-oxidation into BQA (Braconi et al 2010a;Braconi et al 2010b;Tinti et al 2010), corroborating very early in vitro studies demonstrating the production of ROS such as H 2 O 2 e O 2¯˙d uring this reaction (Martin and Batkoff 1987).…”

Section: Resultssupporting

confidence: 78%

See 1 more Smart Citation

Redox‐proteomics of the effects of homogentisic acid in an in vitro human serum model of alkaptonuric ochronosis

Braconi

Bianchini

Bernardini

et al. 2011

J of Inher Metab Disea

Self Cite

View full text Add to dashboard Cite

Alkaptonuria (AKU) is a rare inborn error of metabolism associated with a deficient activity of homogentisate 1,2-dioxygenase (HGO), an enzyme involved in tyrosine and phenylalanine metabolism. Such a deficiency leads to the accumulation of homogentisic acid (HGA) and its oxidized/polymerized products in connective tissues, where melanin-like pigments accumulate (ochronosis). Ochronosis involves especially joints, where an ochronotic arthropathy develops. Little is known on the molecular mechanisms leading to ochronosis and ochronotic arthropathy in AKU. Previous works of ours showed that HGA in vitro propagates oxidative stress through its conversion into benzoquinone acetate (BQA). We hence used an in vitro model consisting of human serum treated with HGA and evaluated the activities of glutathione related anti-oxidant enzymes and levels of compounds indexes of oxidative stress. Proteomics and redox-proteomics were used to identify oxidized proteins and proteins more likely able to bind BQA. Overall, we found that the production of ochronotic pigment in HGA-treated serum is accompanied by lipid peroxidation, decreased activity of the enzyme glutathione peroxidase and massive depletion of thiol groups, together with increased protein carbonylation and thiol oxidation. We also found that BQA was likely to bind carrier proteins and naturally abundant serum proteins, eventually altering their chemico-physical properties. Concluding, our work points towards a critical importance of thiol compounds in counteracting HGA- and BQA- mediated stress in AKU, so that future research for disease biomarkers and pharmacological treatments for AKU and ochronosis will be more easily addressed.

show abstract

Section: Resultssupporting

confidence: 78%

“…The HGA concentration we tested in our model, 0.33 mM (Braconi et al 2010a;Braconi et al 2010b;Tinti et al 2010), is in the range of circulating HGA in AKU patients' serum (between 50 and 400 μM) (Angeles et al 1989). …”

Section: Resultsmentioning

confidence: 99%

Redox‐proteomics of the effects of homogentisic acid in an in vitro human serum model of alkaptonuric ochronosis

Braconi

Bianchini

Bernardini

et al. 2011

J of Inher Metab Disea

Self Cite

View full text Add to dashboard Cite

show abstract

“…From our observations, HGA significantly preserved lipoproteins and liposomes from oxidative damage induced by Cu 2+ ions, and showed remarkable protective effect on the reduction of the levels of total PUFA/cholesterol, inhibiting the increase of their oxidative products. Several evidences suggest that the accumulation of HGA and benzoquinone acetate, a by-product of HGA oxidation, is implicated in inflammation and tissue degeneration observed in alkaptonuria (Braconi et al, 2010;Phornphutkul et al, 2002). Despite the controversial literature results, HGA, in our experimental conditions, showed a significant in vitro protective effect in different systems of oxidative stress, inhibiting the degradation of biological molecules (cholesterol and unsaturated fatty acids).…”

Section: Resultsmentioning

confidence: 60%

“…doi:10.1016/j.foodchem.2011.05.072 effects and it appears to occur through an oxidative mechanism based on the ability of this compound to undergo autoxidation, leading to quinone formation with the production of reactive oxygen species (Hiraku, Yamasaki, & Kawanishi, 1998;Urios et al, 2003). The accumulation of HGA in connective tissues, the formation of its oxidised/polymerised products and oxygen radical generation have been implicated in aetiology of ochronosis, inflammation and tissue degeneration observed in patients with alkaptonuria, a rare genetic disease associated with deficient homogentisate 1,2-dioxygenase activity in the liver (Braconi et al, 2010;Phornphutkul et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

Antioxidant profile of strawberry tree honey and its marker homogentisic acid in several models of oxidative stress

et al. 2011

View full text Add to dashboard Cite

“…Our previous work (Braconi et al, 2010,b; Tinti et al, 2010; Tinti et al, 2011a,2011b; Braconi et al, 2012; Laschi et al, 2012; Millucci et al, 2012; Braconi et al, 2013; Spreafico et al, 2013) suggested that morphological changes of chondrocytes in AKU cartilage may be attributed to apoptosis, but until now no in depth study exists to elucidate if chondroptosis may occur in AKU. Moreover, ultra‐structural observations were complemented with biochemical and proteomic characterization of chondrocytes isolated from the ochronotic cartilage of AKU patients, indicating that AKU chondrocytes are characterized by HGA‐induced apoptosis, protein aggregation, nitric oxide release, and oxidative stress (Tinti et al, 2011a; Laschi et al, 2012; Millucci et al, 2012; Braconi et al, 2013; Spreafico et al, 2013).…”

mentioning

confidence: 99%

Chondroptosis in Alkaptonuric Cartilage

Millucci

Giorgetti

Viti

et al. 2015

Journal Cellular Physiology

Self Cite

View full text Add to dashboard Cite

Alkaptonuria (AKU) is a rare genetic disease that affects the entire joint. Current standard of treatment is palliative and little is known about AKU physiopathology. Chondroptosis, a peculiar type of cell death in cartilage, has been so far reported to occur in osteoarthritis, a rheumatic disease that shares some features with AKU. In the present work, we wanted to assess if chondroptosis might also occur in AKU. Electron microscopy was used to detect the morphological changes of chondrocytes in damaged cartilage distinguishing apoptosis from its variant termed chondroptosis. We adopted histological observation together with Scanning Electron Microscopy and Transmission Electron Microscopy to evaluate morphological cell changes in AKU chondrocytes. Lipid peroxidation in AKU cartilage was detected by fluorescence microscopy. Using the above‐mentioned techniques, we performed a morphological analysis and assessed that AKU chondrocytes undergo phenotypic changes and lipid oxidation, resulting in a progressive loss of articular cartilage structure and function, showing typical features of chondroptosis. To the best of our knowledge, AKU is the second chronic pathology, following osteoarthritis, where chondroptosis has been documented. Our results indicate that Golgi complex plays an important role in the apoptotic process of AKU chondrocytes and suggest a contribution of chondroptosis in AKU pathogenesis. These findings also confirm a similarity between osteoarthritis and AKU. J. Cell. Physiol. 230: 1148–1157, 2015. © 2014 The Authors. Journal of Cellular Physiology Published by Wiley Periodicals, Inc.

show abstract

Evaluation of anti-oxidant treatments in an in vitro model of alkaptonuric ochronosis

Abstract: Our model allows the opening of new anti-oxidant therapeutic strategies to treat alkaptonuric ochronosis.

Cited by 44 publications

References 42 publications

Redox‐proteomics of the effects of homogentisic acid in an in vitro human serum model of alkaptonuric ochronosis

Redox‐proteomics of the effects of homogentisic acid in an in vitro human serum model of alkaptonuric ochronosis

Antioxidant profile of strawberry tree honey and its marker homogentisic acid in several models of oxidative stress

Chondroptosis in Alkaptonuric Cartilage

Contact Info

Product

Resources

About