Functional cyclophilin D moderates platelet adhesion, but enhances the lytic resistance of fibrin

In the course of thrombosis, platelets are exposed to a variety of activating stimuli classified as ‘strong’ (e.g. thrombin and collagen) or ‘mild’ (e.g. ADP). In response, activated platelets adhere to injured vasculature, aggregate, and stabilise the three-dimensional fibrin scaffold of the expanding thrombus. Since ‘strong’ stimuli also induce opening of the mitochondrial permeability transition pore (MPTP) in platelets, the MPTP-enhancer Cyclophilin D (CypD) has been suggested as a critical pharmacological target to influence thrombosis. However, it is poorly understood what role CypD plays in the platelet response to ‘mild’ stimuli which act independently of MPTP. Furthermore, it is unknown how CypD influences platelet-driven clot stabilisation against enzymatic breakdown (fibrinolysis). Here we show that treatment of human platelets with Cyclosporine A (a cyclophilin-inhibitor) boosts ADP-induced adhesion and aggregation, while genetic ablation of CypD in murine platelets enhances adhesion but not aggregation. We also report that platelets lacking CypD preserve their integrity in a fibrin environment, and lose their ability to render clots resistant against fibrinolysis. Our results indicate that CypD has opposing haemostatic roles depending on the stimulus and stage of platelet activation, warranting a careful design of any antithrombotic strategy targeting CypD

Skeletal Muscle NADPH Oxidase Is Increased and Triggers Stretch-Induced Damage in the mdx Mouse

Recent studies have shown that oxidative stress contributes to the pathogenesis of muscle damage in dystrophic (mdx) mice. In this study we have investigated the role of NADPH oxidase as a source of the oxidative stress in these mice. The NADPH oxidase subunits gp91phox, p67phox and rac 1 were increased 2–3 fold in tibilais anterior muscles from mdx mice compared to wild type. Importantly, this increase occurred in 19 day old mice, before the onset of muscle necrosis and inflammation, suggesting that NADPH oxidase is an important source of oxidative stress in mdx muscle. In muscles from 9 week old mdx mice, gp91phox and p67phox were increased 3–4 fold and NADPH oxidase superoxide production was 2 times greater than wild type. In single fibers from mdx muscle NADPH oxidase subunits were all located on or near the sarcolemma, except for p67phox,which was expressed in the cytosol. Pharmacological inhibition of NADPH oxidase significantly reduced the intracellular Ca2+ rise following stretched contractions in mdx single fibers, and also attenuated the loss of muscle force. These results suggest that NADPH oxidase is a major source of reactive oxygen species in dystrophic muscle and its enhanced activity has a stimulatory effect on stretch-induced Ca2+ entry, a key mechanism for muscle damage and functional impairment

Mitochondrial Injury and Protection in Ischemic Pre- and Postconditioning

Mitochondrial damage is a determining factor in causing loss of cardiomyocyte function and viability, yet a mild degree of mitochondrial dysfunction appears to underlie cardioprotection against injury caused by postischemic reperfusion. This review is focused on two major mechanisms of mitochondrial dysfunction, namely, oxidative stress and opening of the mitochondrial permeability transition pore. The formation of reactive oxygen species in mitochondria will be analyzed with regard to factors controlling mitochondrial permeability transition pore opening. Finally, these mitochondrial processes are analyzed with respect to cardioprotection afforded by ischemic pre- and postconditioning

Monoamine oxidase inhibition prevents mitochondrial dysfunction and apoptosis in myoblasts from patients with collagen VI myopathies

AbstractAlthough mitochondrial dysfunction and oxidative stress have been proposed to play a crucial role in several types of muscular dystrophy (MD), whether a causal link between these two alterations exists remains an open question. We have documented that mitochondrial dysfunction through opening of the permeability transition pore plays a key role in myoblasts from patients as well as in mouse models of MD, and that oxidative stress caused by monoamine oxidases (MAO) is involved in myofiber damage. In the present study we have tested whether MAO-dependent oxidative stress is a causal determinant of mitochondrial dysfunction and apoptosis in myoblasts from patients affected by collagen VI myopathies. We find that upon incubation with hydrogen peroxide or the MAO substrate tyramine myoblasts from patients upregulate MAO-B expression and display a significant rise in reactive oxygen species (ROS) levels, with concomitant mitochondrial depolarization. MAO inhibition by pargyline significantly reduced both ROS accumulation and mitochondrial dysfunction, and normalized the increased incidence of apoptosis in myoblasts from patients. Thus, MAO-dependent oxidative stress is causally related to mitochondrial dysfunction and cell death in myoblasts from patients affected by collagen VI myopathies, and inhibition of MAO should be explored as a potential treatment for these diseases

Nasopharyngeal cancer in non-endemic areas: Impact of treatment intensity within a large retrospective multicentre cohort

60siAim: Recommendations for managing patients with nasopharyngeal carcinoma (NPC) in non-endemic areas are largely derived from studies conducted in endemic areas. We analysed the impact of treatment approaches on survival in non-endemic areas. Methods: In an international, multicentre, retrospective study, we analyse consecutive patients with NPC diagnosed between 2004 and 2017 in 36 hospitals from 11 countries. Treatment was categorised as non-intensive (NIT), including radiotherapy alone or concomitant chemoradiotherapy (cCRT), and intensive (IT) including cCRT preceded by and/or followed by chemotherapy (CT). The impact of IT on overall survival (OS) and disease-free survival (DFS) was adjusted for all the available potential confounders. Results: Overall, 1021 and 1113 patients were eligible for overall survival (OS) and disease-free survival (DFS) analyses, respectively; 501 and 554 with Epstein Barr-encoded RNA (EBER) status available. In the whole group, 5-year OS was 84% and DFS 65%. The use of NIT was associated with a risk of death or recurrence 1.37 times higher than patients receiving IT. Patients submitted to NIT and induction CT + concurrent concomitant chemo and three-dimensional Conformal Radiation Therapy (3DCRT) had a risk of death or recurrence 1.5 and 1.7 times higher than patients treated with induction CT + cCRT with intensity-modulated radiotherapy (IMRT), respectively. The IT had no impact on OS in neither patients with EBER+ nor in patients with EBER-; IT showed better DFS in EBER+ but not in patients with EBER-. Conclusions: In low-incidence areas, patients with NPC treated with induction CT followed by concurrent IMRT cCRT achieved the highest DFS rate. The benefit of IT on DFS was restricted to patients with EBER+, suggesting that additional therapy offers no advantages in EBER- cases.restrictedrestrictedBossi P.; Trama A.; Bernasconi A.; Grisanti S.; Mohamad I.; Galiana I.L.; Ozyar E.; Franco P.; Vecchio S.; Bonomo P.; Cirauqui B.C.; El-Sherify M.; Ursino S.; Argiris A.; Pan J.; Wittekindt C.; D'Angelo E.; Costa L.; Buglione M.; Johnson J.; Airoldi M.; Mesia R.; Resteghini C.; Licitra L.; Orlandi E.; Martin M.; Battaglia P.; Turri-Zanoni M.; Lionello M.; Azzarello G.; Boscolo G.; Moro C.; Maffioletti L.; Iannacone E.; Garassino I.; Baatenburg de Jong R.J.; Hardillo J.; Mastromauro C.; Menazza S.; Secondino S.; Montagnani B.F.; Zustovich F.; Da Corte D.; De Renzi F.; Aprile G.; Pancheri F.; Rossetto C.; Ghiani M.; Carta P.; Dessi A.; Cau M.C.; Ramos S.; Charoula H.; Giannakopoulou E.; Verstraete H.; Nevens D.; Velasco M.; Bonfill T.; Restoy E.M.; Franzetti-Pellanda A.Bossi, P.; Trama, A.; Bernasconi, A.; Grisanti, S.; Mohamad, I.; Galiana, I. L.; Ozyar, E.; Franco, P.; Vecchio, S.; Bonomo, P.; Cirauqui, B. C.; El-Sherify, M.; Ursino, S.; Argiris, A.; Pan, J.; Wittekindt, C.; D'Angelo, E.; Costa, L.; Buglione, M.; Johnson, J.; Airoldi, M.; Mesia, R.; Resteghini, C.; Licitra, L.; Orlandi, E.; Martin, M.; Battaglia, P.; Turri-Zanoni, M.; Lionello, M.; Azzarello, G.; Boscolo, G.; Moro, C.; Maffioletti, L.; Iannacone, E.; Garassino, I.; Baatenburg de Jong, R. J.; Hardillo, J.; Mastromauro, C.; Menazza, S.; Secondino, S.; Montagnani, B. F.; Zustovich, F.; Da Corte, D.; De Renzi, F.; Aprile, G.; Pancheri, F.; Rossetto, C.; Ghiani, M.; Carta, P.; Dessi, A.; Cau, M. C.; Ramos, S.; Charoula, H.; Giannakopoulou, E.; Verstraete, H.; Nevens, D.; Velasco, M.; Bonfill, T.; Restoy, E. M.; Franzetti-Pellanda, A