In vitro and in vivo effects of SerpinA1 on the modulation of Transthyretin proteolysis

Transthyretin (TTR) proteolysis has been recognized as a complementary mechanism contributing to transthyretin-related amyloidosis (ATTR amyloidosis). Accordingly, amyloid deposits can be composed mainly of full-length TTR or contain a mixture of both cleaved and full-length TTR, particularly in the heart. The fragmentation pattern at Lys48 suggests the involvement of a serine protease, such as plasmin. The most common TTR variant, TTR V30M, is susceptible to plasmin-mediated proteolysis, and the presence of TTR fragments facilitates TTR amyloidogenesis. Recent studies revealed that the serine protease inhibitor, SerpinA1, was differentially expressed in hepatocyte-like cells (HLCs) from ATTR patients. In this work, we evaluated the effects of SerpinA1 on in vitro and in vivo modulation of TTR V30M proteolysis, aggregation, and deposition. We found that plasmin-mediated TTR proteolysis and aggregation are partially inhibited by SerpinA1. Furthermore, in vivo downregulation of SerpinA1 increased TTR levels in mice plasma and deposition in the cardiac tissue of older animals. The presence of TTR fragments was observed in the heart of young and old mice but not in other tissues following SerpinA1 knockdown. Increased proteolytic activity, particularly plasmin activity, was detected in mice plasmas. Overall, our results indicate that SerpinA1 modulates TTR proteolysis and aggregation in vitro and in vivo.This research was funded by COMPETE 2020 of PT2020 through the European Regional Development Fund (ERDF), “NETDIAMOND—New Targets in DIAstolic heart failure: from coMOrbidities to persoNalizeD medicine” project financed by the European Structural and Investment Funds (ESIF), through the Programa Operacional Regional (POCI-01-0145-FEDER-016385) and HEALTHUNORTE: Setting-up biobanks and regenerative medicine strategies to boost research in cardiovascular, musculoskeletal, neurological, oncological, immunological, and infectious diseases, NORTE- 01-0145-FEDER-000039. FB was supported by FCT—Fundação para a Ciência e Tecnologia/MEC— Ministério da Educação e Ciência with a PhD fellowship (SFRH/BD/123674/2016)

Paramiloidosis in Portugal:reflection on the hepatic transplantation paradigm motivated by an actual case

A Polineuropatia Amiloidótica Familiar de tipo português (PAF) ou ATTR V30M é uma doença hereditária cuja prevalência em Portugal é elevada, sendo diagnosticados cerca de 60 novos casos todos os anos. Uma doente com PAF submeteu-se a um segundo transplante hepático de um dador cadavérico depois de se ter constatado que o primeiro dador era portador de TTR V30M. Com este artigo breve pretende-se realizar uma reflexão sobre o interesse, a prática e o enquadramento legal que condicionam a realização de testes genéticos preditivos em dadores de fígado na transplantação de doentes com paramiloidose. A determinação da presença (ou não) de proteína mutada no soro do segundo dador foi realizada por espectrometria de massa precedida de imunoprecipitação da proteína transtirretina. A realização de testes genéticos que permitam determinar a condição de portador de TTR V30M em dadores de fígado, deveria ser considerada no quadro das políticas de transplante em Portugal.Familial Amyloidotic Polyneuropathy, Portuguese type (FAP), ATTR V30M, is a hereditary disease with high prevalence in Portugal, where 60 new cases are diagnosed each year. An FAP patient underwent a second liver transplantation from a cadaveric donor to treat her condition, after it was discovered that the first donor was a TTR V30M carrier. The purpose of this brief report is to contribute to a reflection on the interest, the procedures and the legal framework that steers the use of predictive genetic tests of liver donors in the transplantation of FAP patients. The presence or absence of the mutated protein in the donor serum was established by immunoprecipitation of TTR followed by mass spectrometry analysis. The implementation of predictive TTR V30M genetic tests, directed at liver donors in the transplantation of FAP patients, should be considered in the framework of the Portuguese transplant policies

The prevalence and distribution of the amyloidogenic transthyretin (TTR) V122I allele in Africa

Transthyretin (TTR) pV142I (rs76992529-A) is one of the 113 variants in the human TTR gene associated with systemic amyloidosis. It results from a G to A transition at a CG dinucleotide in the codon for amino acid 122 of the mature protein (TTR V122I). The allele frequency is 0.0173 in African Americans

A possible role for miRNA silencing in disease phenotype variation in Swedish transthyretin V30M carriers

Our results are the first to show the presence of a 3'UTR polymorphism on the V30M haplotype in Swedish carriers, which can serve as a miRNA binding site potentially leading to down-regulated expression from the mutated TTR allele. This finding may be related to the low penetrance and high age at onset of the disease observed in the Swedish patient population

A narrative review and expert recommendations on the assessment of the clinical manifestations, follow-up, and management of post-OLT patients with ATTRv amyloidosis

Orthotopic liver transplantation (OLT) was the first treatment able to modify the natural course of hereditary transthyretin (ATTRv) amyloidosis, which is a rare and fatal disorder caused by the accumulation of misfolded transthyretin (TTR) variants in different organs and tissues and which leads to a progressive and multisystem dysfunction. Because the liver is the main source of TTR, OLT dramatically reduces the production of the pathogenic TTR variant, which should prevent amyloid formation and halt disease progression. However, amyloidosis progression may occur after OLT due to wild-type TTR deposition, especially in the nerves and heart. In this review, we discuss the disease features influencing OLT outcomes and the clinical manifestations of ATTRv amyloidosis progression post-OLT to improve our understanding of disease worsening after OLT and optimize the follow-up and clinical management of these patients. By conducting a literature review on the PubMed database, we identified patient characteristics that have been associated with worse post-OLT outcomes, including late-onset V50M and non-V50M variants, age >40 years, long disease duration, advanced neuropathy and autonomic dysfunction, and malnutrition. Regarding post-OLT mortality, deaths occurring within the first year after OLT were mainly associated with fatal graft complications and infectious diseases, whereas cardiovascular-related deaths usually occurred later. Considering the diverse clinical manifestations of ATTRv amyloidosis progression post-OLT, including worsening neuropathy and/or cardiomyopathy, autonomic dysfunction, and oculoleptomeningeal involvement, we present advice on the most relevant tests for assessing disease progression post-OLT. Finally, we discuss the use of new therapies based on TTR stabilizers and TTR mRNA silencers for the treatment of ATTRv amyloidosis patients post-OLT

C1QA and C1QC modify age-at-onset in familial amyloid polyneuropathy patients

Objectives: Transthyretin (TTR) familial amyloid polyneuropathy (FAP) (OMIM 176300) shows a variable age-at-onset (AO), including within families. We hypothesized that variants in C1QA and C1QC genes, might also act as genetic modifiers of AO in TTR-FAP Val30Met Portuguese patients. Methods: We analyzed DNA samples of 267 patients (117 families). To search for variants, all exons and flanking regions were genotyped by automated sequencing. We used generalized estimating equations (GEEs) to take into account the nonindependency of AO among relatives. Intensive in silico analyses were performed, using various software to assess miRNAs target sites, splicing sites, transcription factor binding sites alterations, and gene–gene interactions. Results: Two variants for C1QA gene, GA genotype of rs201693493 (P < 0.001) and CT genotype of rs149050968 (P < 0.001), were significantly associated with later AO. In silico analysis demonstrated, that rs201693493 may alter splicing activity. Regarding C1QC, we found three statistically significant results: GA genotype of rs2935537 (P = 0.003), GA genotype of rs201241346 (P < 0.001) and GA genotype of rs200952686 (P < 0.001). The first two were associated with earlier AO, whereas the third was associated with later-onset. Interpretation: C1QA was associated with later onset, whereas C1QC may have a double role: variants may confer earlier or later AO. As found in a study in Cyprus, we confirmed the role of complement C1Q genes (and thus of inflammation) as modulator of AO in Portuguese patients with TTR-FAP Val30Met.We would like to thank FEDER funds, through the Programa Operacional Factores de Competitividade – COMPETE 2020 and by Nacional funds through the FCT – Fundação para a Ciência e a Tecnologia [COMPETE: POCI-01-0145-FEDER-007440]. This work was supported by grants of Fundação para a Ciência e Tecnologia, FCT [PTDC/SAU GMG/100240/2008 and PEsT], co-funded by ERDF and COMPETE; and by Financiamento Plurianual de Unidades de Investigac¸a˜ o (FCT). DS is the recipient of a FCT fellowship [SFRH/BD/91160/2012]. MAF is recipient of a FCT fellowship [SFRH/BD/101352/2014]

Marked biochemical difference in amyloid proportion between intra- and extraocular tissues in a liver-transplanted patient with hereditary ATTR amyloidosis（肝移植後FAP患者の眼内・眼外沈着アミロイドにおけるアミロイド蛋白組成の顕著な生化学的相違）

信州大学(Shinshu university)博士（医学）雑誌に発表。Amyloid. 24(1):17-23 (2017); doi:10.1080/13506129.2016.1276055.Thesis吉長　恒明. Marked biochemical difference in amyloid proportion between intra- and extraocular tissues in a liver-transplanted patient with hereditary ATTR amyloidosis（肝移植後FAP患者の眼内・眼外沈着アミロイドにおけるアミロイド蛋白組成の顕著な生化学的相違）. 信州大学, 2017, 博士論文.doctoral thesi

In silico analysis of TTR gene (coding and non-coding regions, and interactive network) and its implications in transthyretin-related amyloidosis.

Introduction: Transthyretin (TTR)-related amyloidosis is a life-threatening disease. Currently, several questions about the pathogenic mechanisms of TTR-related amyloidosis remain unanswered. Methods: We have investigated various TTR-related issues using different in silico approaches. Results: Using an amino acid similarity-based analysis, we have indicated the most relevant TTR secondary structures in determining mutation impact. Our amyloidogenic propensity analysis of TTR missense substitutions has highlighted a similar pattern for wild-type and mutated TTR amino b acid sequences. However, some mutations present differences with respect to the general distribution. We have identified non-coding variants in cis-regulatory elements of the TTR gene, and our analysis on V122I-related haplotypes has indicated differences in non-coding regulatory variants, suggesting differences among V122I carriers. The analysis of methylation status indicated CpG sites that may affect TTR expression. Finally, our interactive network analysis revealed functional partners of TTR that may play a modifier role in the pathogenesis of TTR-related amyloidosis. Discussion and conclusion: Our data provided new insights into the pathogenesis of TTR-related amyloidosis that, if they were to be confirmed through experimental investigations, could significantly improve our understanding of the disease

Coexistence of transthyretin- and Aβ-type cerebral amyloid angiopathy in a patient with hereditary transthyretin V30M amyloidosis

金沢大学附属病院神経内科Embargo Period 12 month