Quality control of fibrinogen secretion in the molecular pathogenesis of congenital afibrinogenemia

Congenital afibrinogenemia is a rare bleeding disorder characterized by the absence in circulation of fibrinogen, a hexamer composed of two sets of three polypeptides (Aα, Bβ and γ). Each polypeptide is encoded by a distinct gene, FGA, FGB and FGG, all three clustered in a region of 50 kb on 4q31. A subset of afibrinogenemia mutations has been shown to specifically impair fibrinogen secretion, but the underlying molecular mechanisms remained to be elucidated. Here, we show that truncation of the seven most C-terminal residues (R455-Q461) of the Bβ chain specifically inhibits fibrinogen secretion. Expression of additional mutants and structural modelling suggests that neither the last six residues nor R455 is crucial per se for secretion, but prevent protein misfolding by protecting hydrophobic residues in the βC core. Immunofluorescence and immuno-electron microscopy studies indicate that secretion-impaired mutants are retained in a pre-Golgi compartment. In addition, expression of Bβ, γ and angiopoietin-2 chimeric molecules demonstrated that the βC domain prevents the secretion of single chains and complexes, whereas the γC domain allows their secretion. Our data provide new insight into the mechanisms accounting for the quality control of fibrinogen secretion and confirm that mutant fibrinogen retention is one of the pathological mechanisms responsible for congenital afibrinogenemi

p63 is an alternative p53 repressor in melanoma that confers chemoresistance and a poor prognosis.

The role of apoptosis in melanoma pathogenesis and chemoresistance is poorly characterized. Mutations in TP53 occur infrequently, yet the TP53 apoptotic pathway is often abrogated. This may result from alterations in TP53 family members, including the TP53 homologue TP63. Here we demonstrate that TP63 has an antiapoptotic role in melanoma and is responsible for mediating chemoresistance. Although p63 was not expressed in primary melanocytes, up-regulation of p63 mRNA and protein was observed in melanoma cell lines and clinical samples, providing the first evidence of significant p63 expression in this lineage. Upon genotoxic stress, endogenous p63 isoforms were stabilized in both nuclear and mitochondrial subcellular compartments. Our data provide evidence of a physiological interaction between p63 with p53 whereby translocation of p63 to the mitochondria occurred through a codependent process with p53, whereas accumulation of p53 in the nucleus was prevented by p63. Using RNA interference technology, both isoforms of p63 (TA and ΔNp63) were demonstrated to confer chemoresistance, revealing a novel oncogenic role for p63 in melanoma cells. Furthermore, expression of p63 in both primary and metastatic melanoma clinical samples significantly correlated with melanoma-specific deaths in these patients. Ultimately, these observations provide a possible explanation for abrogation of the p53-mediated apoptotic pathway in melanoma, implicating novel approaches aimed at sensitizing melanoma to therapeutic agents

Rapporto 2007 su consumo e dipendenze da sostanze in Emilia-Romagna.

Report on the state of legal and illegal substances use in the territory of Emilia-Romagna Region.Il report analizza il fenomeno delle dipendenze nel territorio della Regione Emilia-Romagna. La descrizione del fenomeno si sviluppa intorno all\u27analisi degli indicatori individuati dall\u27Osservatorio Europeo delle Dipendenze di Lisbona (OEDT): 1-uso di sostanze nella popolazione generale (questo indicatore va a rilevare i comportamenti nei confronti di alcol e sostanze psicoattive da parte della popolazione generale); 2-prevalenza d\u27uso problematico delle sostanze psicoattive; 3-domanda di trattamento degli utilizzatori di sostanze; 4-mortalit? degli utilizzatori di sostanze; 5-malattie infettive. Altri due importanti indicatori che si stanno sviluppando, e che vengono qui illustrati, sono l\u27analisi delle Schede di Dimissione Ospedaliera (SDO) e gli indicatori relativi alle conseguenza sociali dell\u27uso di droghe (criminalit? droga correlata). Inoltre sono state applicate diverse metodologie standard di stima sia per quantificare la quota parte sconosciuta di utilizzatori di sostanze che non afferiscono ai servizi, sia per identificarne alcune caratteristiche

Quality control of fibrinogen secretion in the molecular pathogenesis of congenital afibrinogenemia

Congenital afibrinogenemia is a rare bleeding disorder characterized by the absence in circulation of fibrinogen, a hexamer composed of two sets of three polypeptides (Aalpha, Bbeta and gamma). Each polypeptide is encoded by a distinct gene, FGA, FGB and FGG, all three clustered in a region of 50 kb on 4q31. A subset of afibrinogenemia mutations has been shown to specifically impair fibrinogen secretion, but the underlying molecular mechanisms remained to be elucidated. Here, we show that truncation of the seven most C-terminal residues (R455-Q461) of the Bbeta chain specifically inhibits fibrinogen secretion. Expression of additional mutants and structural modelling suggests that neither the last six residues nor R455 is crucial per se for secretion, but prevent protein misfolding by protecting hydrophobic residues in the betaC core. Immunofluorescence and immuno-electron microscopy studies indicate that secretion-impaired mutants are retained in a pre-Golgi compartment. In addition, expression of Bbeta, gamma and angiopoietin-2 chimeric molecules demonstrated that the betaC domain prevents the secretion of single chains and complexes, whereas the gammaC domain allows their secretion. Our data provide new insight into the mechanisms accounting for the quality control of fibrinogen secretion and confirm that mutant fibrinogen retention is one of the pathological mechanisms responsible for congenital afibrinogenemia

Neurodegenerative VPS41 variants inhibit HOPS function and mTORC1-dependent TFEB/TFE3 regulation

Contains fulltext : 233577.pdf (Publisher’s version ) (Open Access

Model of Care for Microelimination of Hepatitis C Virus Infection among People Who Inject Drugs

Background: People who inject drugs (PWID) are the largest group at risk for HCV infection. Despite the direct acting antivirals (DAA) advancements, HCV elimination has been hindered by real-life difficulties in PWID. Aims: This study aimed to assess the impact of a multidisciplinary intervention strategy where HCV screening, treatment and follow-up were performed at the same location on efficacy and safety of DAA-therapy in real-life PWID population. Methods: All HCV-infected PWID referred to five specialized outpatient centers for drug addicts (SerDs) in Northern Italy were prospectively enrolled from May 2015 to December 2019. Hepatologists and SerDs healthcare workers collaborated together in the management of PWID inside the SerDs. Sustained virologic response (SVR), safety of treatment, proportion of patients lost to follow-up and reinfection rate were evaluated. Results: A total of 358 PWID started antiviral treatment. About 50% of patients had advanced fibrosis/cirrhosis, 69% received opioid substitution treatment, and 20.7% self-reported recent injecting use. SVR was achieved in 338 (94.4%) patients. Two patients died during treatment; one prematurely discontinued, resulting in a non-responder; twelve were lost during treatment/follow-up; and five relapsed. No serious adverse events were reported. SVR was lower in recent PWID than in former ones (89.2% vs. 95.8%; p = 0.028). Seven reinfections were detected, equating to an incidence of 1.25/100 person-years. Reinfection was associated with recent drug use (OR 11.07, 95%CI 2.10–58.38; p = 0.005). Conclusion: Our embedded treatment model could be appropriate to increase the linkage to care of HCV-infected PWID. In this setting, DAA regimens are well tolerated and highly effective, achieving a lower rate of reinfection

Neurodegenerative VPS41 variants inhibit HOPS function and mTORC1‐dependent TFEB/TFE3 regulation

Abstract Vacuolar protein sorting 41 (VPS41) is as part of the Homotypic fusion and Protein Sorting (HOPS) complex required for lysosomal fusion events and, independent of HOPS, for regulated secretion. Here, we report three patients with compound heterozygous mutations in VPS41 (VPS41S285P and VPS41R662*; VPS41c.1423‐2A>G and VPS41R662*) displaying neurodegeneration with ataxia and dystonia. Cellular consequences were investigated in patient fibroblasts and VPS41‐depleted HeLa cells. All mutants prevented formation of a functional HOPS complex, causing delayed lysosomal delivery of endocytic and autophagic cargo. By contrast, VPS41S285P enabled regulated secretion. Strikingly, loss of VPS41 function caused a cytosolic redistribution of mTORC1, continuous nuclear localization of Transcription Factor E3 (TFE3), enhanced levels of LC3II, and a reduced autophagic response to nutrient starvation. Phosphorylation of mTORC1 substrates S6K1 and 4EBP1 was not affected. In a C. elegans model of Parkinson’s disease, co‐expression of VPS41S285P/VPS41R662* abolished the neuroprotective function of VPS41 against α‐synuclein aggregates. We conclude that the VPS41 variants specifically abrogate HOPS function, which interferes with the TFEB/TFE3 axis of mTORC1 signaling, and cause a neurodegenerative disease