Profiling Dopamine-Induced Oxidized Proteoforms of β-synuclein by Top-Down Mass Spectrometry

The formation of multiple proteoforms by post-translational modifications (PTMs) enables a single protein to acquire distinct functional roles in its biological context. Oxidation of methionine residues (Met) is a common PTM, involved in physiological (e.g., signaling) and pathological (e.g., oxidative stress) states. This PTM typically maps at multiple protein sites, generating a heterogeneous population of proteoforms with specific biophysical and biochemical properties. The identification and quantitation of the variety of oxidized proteoforms originated under a given condition is required to assess the exact molecular nature of the species responsible for the process under investigation. In this work, the binding and oxidation of human β-synuclein (BS) by dopamine (DA) has been explored. Native mass spectrometry (MS) has been employed to analyze the interaction of BS with DA. In a second step, top-down fragmentation of the intact protein from denaturing conditions has been performed to identify and quantify the distinct proteoforms generated by DA-induced oxidation. The analysis of isobaric proteoforms is approached by a combination of electron-transfer dissociation (ETD) at each extent of modification, quantitation of methionine-containing fragments and combinatorial analysis of the fragmentation products by multiple linear regression. This procedure represents a promising approach to systematic assessment of proteoforms variety and their relative abundance. The method can be adapted, in principle, to any protein containing any number of methionine residues, allowing for a full structural characterization of the protein oxidation states

Rare occurrence of pseudomyxoma peritonei (PMP) syndrome arising from a malignant transformed ovarian primary mature cystic teratoma treated by cytoreductive surgery and HIPEC: a case report

Background: Pseudomyxoma peritonei (PMP) syndrome is a disease process that typically occurs from ruptured appendiceal mucocele neoplasms. PMP syndrome arising from malignant transformation of an ovarian primary mature cystic teratoma (MCT) is a pathogenesis rarely encountered. Case presentation: Herein, we report a 28-year-old patient evaluated and treated for a right ovarian mass and large volume symptomatic abdominopelvic mucinous ascites. Molecular profiling and genetic analysis revealed mutations in ATM, GNAS, and KRAS proteins while IHC demonstrated gastrointestinal-specific staining for CK20, CDX2, CK7, and SATB2. Peritoneal cytology showed paucicellular mucin. Diffuse peritoneal adenomucinosis (DPAM) variant of PMP arising from a ruptured ovarian primary MCT after malignant transformation to a low-grade appendiceal-like mucinous neoplasm was ultimately confirmed. Treatment included staged therapeutic tumor debulking and right salpingo-oophorectomy followed by cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC). Conclusions: Our report builds upon the existing literature supporting this aggressive treatment option reserved for advanced abdominal malignancies utilized in this patient with a rare clinical entity

Methionine oxidation in α-synuclein inhibits its propensity for ordered secondary structure.

α-Synuclein (AS) is an intrinsically disordered protein highly expressed in dopaminergic neurons. Its amyloid aggregates are the major component of Lewy bodies, a hallmark of Parkinson's disease (PD). AS is particularly exposed to oxidation of its methionine residues, both in vivo and in vitro. Oxidative stress has been implicated in PD and oxidized α-synuclein has been shown to assemble into soluble, toxic oligomers, rather than amyloid fibrils. However, the structural effects of methionine oxidation are still poorly understood. In this work, oxidized AS was obtained by prolonged incubations with dopamine (DA) or epigallocatechin-3-gallate (EGCG), two inhibitors of AS aggregation, indicating that EGCG promotes the same final oxidation product as DA. The conformational transitions of the oxidized and non-oxidized protein were monitored by complementary biophysical techniques, including MS, ion mobility (IM), CD and FTIR spectroscopy assays. Although the two variants displayed very similar structures under conditions that stabilize highly disordered or highly ordered states, differences emerged in the intermediate points of transitions induced by organic solvents, such as trifluoroethanol (TFE) and methanol (MeOH), indicating a lower propensity of the oxidized protein for forming either α- or β-type secondary structure. Furthermore, oxidized AS displayed restricted secondary-structure transitions in response to dehydration and slightly amplified tertiary-structure transitions induced by ligand binding. This difference in susceptibility to induced folding could explain the loss of fibrillation potential observed for oxidized AS

The smart city as urban eco-modernisation: the case of Masdar City in Abu Dhabi

This chapter explores the notion and practice of the smart city with a geographical focus on Abu Dhabi, the capital city of the United Arab Emirates. Smart-city projects are understood and discussed as the product of overarching political economies related to fast-track urbanisation. The case of Abu Dhabi shows that smart-city initiatives are connected to the state’s goals of changing its economic base and preserving the political status quo, through the development and commercialization of smart-clean technology. In this sense, the smart city, as a living laboratory meant to produce new cleantech products such as smart grids and state-of-the-art solar power stations, becomes the physical locus where new strands of the regional economy are cultivated. Through the example of Masdar City, a new high-tech city under construction in Abu Dhabi, the chapter unpacks and critiques the contradictions between the economic imperatives that underpin so-called smart interventions and their overall sustainability, revealing that, as in most cases of ecological modernisation, socio-environmental concerns are overshadowed by business interests. We conclude that, in addition to being ineffective against the social and the environmental problems caused by cities, by supporting transnational machines of production and consumption, smart-city solutions risk to backfire and exacerbate the same vicious circle that they should be breaking.

New Methods for Studying Transnational Urbanism and Architecture: A primer

Thanks to new technological advancements and due to global economic arrangements, today architectural firms simultaneously practice in multiple countries. Extremely complex projects, such as iconic museums or tall skyscrapers are often awarded to architects who are internationally known. The role and contribution of such architectural and urban projects in contemporary cities have been heatedly debated in both scholarly and public arenas for quite some time now. Nonetheless no one has collected systematic evidence regarding the magnitude of transnational projects, their histories and geographical trajectories, the strategies of multinational design firms and how cities plan such projects. This paper provides an early account of ongoing research activities for constituting the first spatial database dedicated to mapping transnational projects and to developing qualitative and quantitative methods