158 research outputs found
Riparto dei governi e delle comunita dello Stato pontificio : con i loro respettivi appodiati.
No full textSigned p. 140: "Dalla Segretaria di Stato ... E. Card. Consalvi."Mode of access: Internet
HDAC inhibitors for muscular dystrophies: progress and prospects
No full textHDAC inhibitors for muscular dystrophies: progress and prospects
Duchenne muscular dystrophy (DMD) is the most common and severe form of muscular dystrophy (MD) that affects 1 in 3500–6000 live male births. This lethal X-linked genetic disease is caused by muta- tions in dystrophin gene that leads to a complete absence of the protein, thereby compromising the structural and functional integrity of the dystrophin- associated protein complex (DAPC).[1] The DAPC links the actin cytoskeleton to the extracellular matrix and has an essential role in stabilizing the sarcolemma during repeated cycles of contraction.[2] As such, dystrophin-deficient muscles are vulnerable to mechanical damage and develop progressive muscu- lar weakness, as a consequence of muscle degenera- tion, leading to loss of myofibers, which are ultimately replaced by fibrotic scars and fat deposition.[3] There is still no available cure for DMD, but only palliative treatments that aim to counter muscle loss, thereby extending patient mobility and delaying the onset of respiratory and cardiac problems.[4]
The progression of DMD is highly influenced by the ability of dystrophin-deficient muscles to counter mus- cle loss by a regenerative response, which typically defines a clinical latency observed during the early stages of the disease. The gradual exhaustion of such compensatory response coincides with changes in the muscle tissue composition, leading to the progressive formation of fibrotic and adipose tissue in place of contractile fibers. This ‘restriction point’ in the natural history of DMD is due to alterations in the interactions between the cell types that contribute to promote regeneration, eventually culminating with a switch of muscle repair toward fibrotic and fat deposition.[5] In particular, studies in the last decade have revealed the importance of changes in the identity and functional properties of the cellular components of the muscle stem (satellite) cell (MuSC) niche. For instance, the inter- actions between inflammatory cells (e.g. macrophages), interstitial ‘support’ cells (e.g. fibro-adipogenic progeni- tors – FAPs) and MuSCs appear a key determinant to drive the skeletal muscle toward a regeneration or degeneration process.[6,7] This notion has inspired a number of current pharmacological strategies aimed at targeting these cells and the functional networks they establish,[8,9] as an alternative to gene replace- ment and cell-based strategies.
Among the pharmacological interventions that aim to slow down the disease progression by targeting key events downstream of the genetic defect, the histone deacetylase inhibitors (HDACi) have recently been translated into a clinical trial, based on the encouraging preclincial data generated in the mouse model of DMD – the mdx mice.[10,11]
In principle, the rationale for the use of HDACi in the treatment of DMD was provided by the finding that dystrophin-deficient muscles display an aberrant, con- stitutive activation of HDAC2, as a consequence of reduced nitric oxide (NO)-mediated NO-dependent S-nitrosylation in myofibers.[12] Moreover, recent stu- dies have revealed complex epigenetic networks tar- geted by HDACi in MuSCs and FAPs.[13,14] In particular, studies from Saccone et al. have identified an HDAC-regulated network that controls the func- tional phenotype of FAPs from dystrophic muscles. Treatment with HDACi promotes the expression of two core components of the myogenic transcriptional machinery, MyoD and BAF60c [15] and upregulates three myogenic microRNA involved into muscle differ- entiation (myomiRs; miR-1.2, miR-133 and miR-206) in FAPs. MyomiRs in turn target two alternative BAF60 variants – BAF60 A and B – that when incorporated into the Switch/Sucrose NonFermentable (SWI/SNF) chromatin-remodeling complex would otherwise pro- mote the activation of the fibro-adipogenic program. [14] Thus, HDACi-mediated selection of BAF60 C-based SWI/SNF complex appears to mediate a therapeutic switch of FAP phenotype from pro-fibroadipogenic to pro-myogenic one. Interestingly, FAPs from dystrophic muscles at advanced stage of disease are resistant to the beneficial effects of HDACi, accounting for the stage-specific effect of HDACi previously observed by Mozzetta et al.[9] Genome-wide studies of chromatin accessibility showed that at early stages of the disease, HDACi promote an extensive chromatin remodeling, which was not observed at late stage of the disease. [14] This finding indicates that pharmacological inter- ventions that target FAPs could be used to promote compensatory regeneration, while preventing fibro- adipogenic degeneration of DMD muscles. It also sug- gests that FAPs of dystrophic muscles at late stages of DMD progression might acquire a chromatin conforma- tion that confers resistance to treatments that are
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126 M. SANDONÁ ET AL.
otherwise effective at early stages of disease. Understanding the molecular basis of such resistance could reveal novel targets for interventions aimed at restoring the ability of FAPs to support muscle regen- eration rather than fibrosis and fat infiltration in a larger population of patients.
Conclusion
As preclinical evidence supported the rationale for the use of HDACi in the treatment of DMD, the HDACi Givinostat has been launched as the first epigenetic drug tested in a Phase I/II clinical trial on DMD boys between 8 and 10 years of age that is currently under investigation. Given the potential of HDACi to promote regeneration at the expense of fibro-adipogenic degen- eration, one predicted effect of Givinostat on DMD muscles is to extend the compensatory regeneration and delay the disease progression in patients at early stages of disease progression, Future research should evaluate the efficacy of Givinostat in a larger population of DMD patients and identify molecular criteria and noninvasive biomarkers that define patient responsive- ness and eventually inspire further interventions that sensitize to HDACi unresponsive patients.
Expert opinion
Three fundamental aspects for the future development of HDACi-based therapies concern a) the identification of biomarkers that help selecting patients for clinical studies and monitoring their responsiveness to the treatments, b) the discovery of complementary approaches that synergize with HDACi to provide an optimal combined therapeutic intervention and c) the potential extension of HDACi-based treatments to other forms of muscular dystrophies.
While the analysis of muscle biopsies is currently regarded as the most reliable readout of the histologi- cal effects of HDACi, this procedure is invasive, is lim- ited to one specific muscle and cannot be repeated multiple times during the course of clinical trials. As such, it is currently missing an effective readout of the efficacy of treatment with HDACi or similar pharmaco- logical approaches. Identification of circulating biomar- kers and/or setting noninvasive or semi-invasive procedures for the evaluation of the effects of pharma- cological interventions is clearly a fundamental step to further move forward pro-clinical and clinical research on DMD.
Moreover, beyond the beneficial effects on muscle histology, the clinical efficacy of HDACi treatment needs to be correlated with functional tests. Studies with
HDACi in mdx mice demonstrated that the morpholo- gical recovery is accompanied by increased muscle strength and exercise performance.[10,11] Thus, match- ing functional tests, such as 6 Minute Walk Test (6MWT) and North Star Ambulatory Assessment, with the histo- logical evaluation of treated muscles, will be mandatory to reveal the efficacy of HDACi and other pharmacolo- gical interventions in DMD patients.
Regarding the identification of complementary approaches that synergize with HDACi, the most urgent questions relate to the functional interactions between HDACi and steroids – the standard treatment currently used in the treatment of DMD. In this case, it is inter- esting to note that steroids are typically acting through a nuclear receptor – the glucocorticoid receptor (GR) – whose activity is negatively regulated by an HDAC- containing repressive complex. Moreover, the possibi- lity to combine HDACi-based treatment with emerging strategies toward re-introducing functional dystrophin in DMD muscles (i.e. exon skipping or future CRISPR- based interventions) is supported by a strong rationale consisting of the necessity to protect the newly formed myofibers, induced by HDACi-promoted regeneration, from contraction-mediated regeneration, via dystrophin re-expression.
Finally, future research should determine the poten- tial efficacy of HDACi on other forms of muscular dys- trophies that share pathogenic events with DMD, e.g. the shift from compensatory regeneration to fibrosis and fat deposition.
Declaration of interest
Funding has been received from AFM Telethon and Duchenne Parent Project (DPP-NL). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock owner- ship or options, expert testimony, grants or patents received or pending, or royalties.
References
Papers of special note have been highlighted as either of interest (•) or of considerable interest (••) to readers.
1. Dalkilic I, Kunkel LM. Muscular dystrophies: genes to pathogenesis. Curr Opin Genet Dev. 2003;13(3):231–238. 2. Petrof BJ, Shrager JB, Stedman HH, et al. Dystrophin protects the sarcolemma from stresses developed during muscle
contraction. Proc Natl Acad Sci USA. 1993;90(8):3710–3714. 3. Straub V, Campbell KP. Muscular dystrophies and the dystrophin-glycoprotein complex. Curr Opin Neurol.
1997;10(2):168–175.
4. Mercuri E, Muntoni F. Muscular dystrophy: new chal-
lenges and review of the current clinical trials. Curr
Opin Pediatr. 2013;25(6):701–707. DOI:10.1097/
MOP.0b013e328365ace5.
5. Serrano AL, Mann CJ, Vidal B, et al. Cellular and molecular
mechanisms regulating fibrosis in skeletal muscle repair and disease. Curr Top Dev Biol. 2011;96:167–201. DOI:10.1016/B978-0-12-385940-2.00007-3.
6. Farup J, Madaro L, Puri PL, et al. Interactions between muscle stem cells, mesenchymal-derived cells and immune cells in muscle homeostasis, regeneration and disease. Cell Death Dis. 2015;6:e1830. DOI:10.1038/ cddis.2015.198.
7. Judson RN, Zhang RH, Rossi FM. Tissue-resident mesenchymal stem/progenitor cells in skeletal muscle: collaborators or saboteurs? Febs J. 2013;280 (17):4100–4108. DOI:10.1111/febs.12370.
8. Lemos DR, Babaeijandaghi F, Low M, et al. Nilotinib reduces muscle fibrosis in chronic muscle injury by promoting TNF-mediated apoptosis of fibro/adipogenic progenitors. Nat Med. 2015;21(7):786–794. DOI:10.1038/nm.3869.
9. Mozzetta C, Consalvi S, Saccone V, et al. Fibroadipogenic progenitors mediate the ability of HDAC inhibitors to promote regeneration in dystrophic muscles of young, but not old Mdx mice. EMBO Mol Med. 2013;5 (4):626–639. DOI:10.1002/emmm.201202096.
• Exciting paper studying the fibroadipogenic pro- genitors (FAPs) as cellular determinants of the ben- eficial effects of HDAC inhibitors. FAPs mediate HDACi effects promoting muscles regeneration in a stage-specific manner.
10. Minetti GC, Colussi C, Adami R, et al. Functional and morphological recovery of dystrophic muscles in mice treated with deacetylase inhibitors. Nat Med. 2006;12 (10):1147–1150.
• Interesting paper describing the functional and mor- phological effects of HDAC inhibitors treatments. HDAC inhibitors increase myofiber size and counter the functional decline of dystrophic muscles
11. Consalvi S, Mozzetta C, Bettica P, et al. Preclinical studies in the mdx mouse model of Duchenne muscular dystro- phy with the histone deacetylase inhibitor Givinostat. Mol Med. 2013;19:79–87. DOI:10.2119/molmed.2013.00011.
•• Excellentpaperdemonstratingtheeffectivenessofa long-term treatment with Givinostat. The findings of this paper provide preclinical basis for a translation on DMD patients.
12. Colussi C, Mozzetta C, Gurtner A, et al. HDAC2 blockade by nitric oxide and histone deacetylase inhibitors reveals
a common target in Duchenne muscular dystrophy treatment. Proc Natl Acad Sci USA. 2008;105 (49):19183–19187. DOI:10.1073/pnas.0805514105.
13. Cacchiarelli D, Martone J, Girardi E, et al. MicroRNAs involved in molecular circuitries relevant for the Duchenne muscular dystrophy pathogenesis are controlled by the dystrophin/nNOS pathway. Cell Metab. 2010;12(4):341–351. DOI:10.1016/j. cmet.2010.07.008.
14. Saccone V, Consalvi S, Giordani L, et al. HDAC-regulated myomiRs control BAF60 variant exchange and direct the functional phenotype of fibro-adipogenic progenitors in dystrophic muscles. Genes Dev. 2014;28(8):841–857. DOI:10.1101/gad.234468.113.
• Fascinating paper determines the molecular mechan- ism that controls the FAPs switch from a fibroadipo- genic to a myogenic phenotype after HDACi treatment.
15. Forcales SV, Albini S, Giordani L, et al. Signal-dependent incorporation of MyoD-BAF60c into Brg1-based SWI/SNF chromatin-remodelling complex. Embo J. 2012;31(2):301–316. DOI:10.1038/emboj. 2011.391.
M. Sandoná
IRCCS Fondazione Santa Lucia, Rome, Italy DAHFMO, Unit of Histology and Medical Embryology, Sapienza University of Rome, Rome, Italy
S. Consalvi
IRCCS Fondazione Santa Lucia, Rome, Italy
L. Tucciarone
IRCCS Fondazione Santa Lucia, Rome, Italy
P. L. Puri
IRCCS Fondazione Santa Lucia, Rome, Italy Muscle Development and Regeneration Program, Sanford Children’s Health Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
V. Saccone
IRCCS Fondazione Santa Lucia, Rome, Ital
Epigenetic reprogramming of muscle progenitors: inspiration for clinical therapies
No full textIn the context of regenerative medicine, based on the potential of stem cells to restore diseased tissues, epigenetics is becoming a pivotal area of interest. Therapeutic interventions that promote tissue and organ regeneration have as primary objective the selective control of gene expression in adult stem cells. This requires a deep understanding of the epigenetic mechanisms controlling transcriptional programs in tissue progenitors. This review attempts to elucidate the principle epigenetic regulations responsible of stem cells differentiation. In particular we focus on the current understanding of the epigenetic networks that regulate differentiation of muscle progenitors by the concerted action of chromatin-modifying enzymes and noncoding RNAs. The novel exciting role of exosome-bound microRNA in mediating epigenetic information transfer is also discussed. Finally we show an overview of the epigenetic strategies and therapies that aim to potentiate muscle regeneration and counteract the progression of Duchenne Muscular Dystrophy (DMD)
THE AMINO ACID SEQUENCE OF GLUTAMATE DEHYDROGENASE FROM Pyrococcus furiosus, A HYPERTERMOPHILIC ARCHAEBACTERIUM .
No full textThe complete amino acid sequence of glutamate dehydrogenase from the archaebacterium Pyrococcus furiosus has been determined. The sequence was reconstructed by automated sequence analysis of peptides obtained after cleavage with cyanogen bromide, Asp-N endoproteinase, trypsin, or pepsin. The enzyme subunit is composed of 420 amino acid residues yielding a molecular mass of 47,122D. In the recently determined primary structure of glutamate dehydrogenase from another thermophilic archaebacterium, Sulfolobus solfataricus, the presence of some methylated lysines was detected and the possible role of this posttranslational modification in enhancing the thermostability of the enzyme was discussed (Maras, B., Consalvi, V., Chiaraluce, R., Politi, L., De Rosa, M., Bossa, F., Scandurra, R., and Barra, D. (1992), fur. J. Biochem. 203, 81-87). In the primary structure reported here, such posttranslational modification has not been found, indicating that the role of lysine methylation should be revisited. Comparison of the sequence of glutamate dehydrogenase from Pyrococcus furiosus with that of S. solfataricus shows a 43.7% similarity, thus indicating a common evolutionary pathway
La questione religiosa negli anni del congresso di Vienna
No full textLa relazione discute criticamente le varie posizioni emerse al congresso di Vienna sul problema religioso, soffermandosi in particolare sui dibattiti che animarono la redazione della costituzione del Deutscher Bund e sull'azione diplomatica del cardinale Consalvi
COVALENTLY BOUND PYRUVATE IN PHOSPHOPANTOTHENOYLCYSTEINE DECARBOXYLASE FROM HORSE LIVER
No full textHorse liver phosphopantothenoylcysteine decarboxylase (EC 4.1.1.36) incorporates nonexchangeable tritium from borotritide with a decrease of the activity. Substrate prevents both tritium incorporation and the decrease in activity. Acid and base hydrolysis of the tritiated protein releases labeled lactate identified by high-voltage paper electrophoresis, paper chromatography and silicic acid chromatography. These results indicate the presence of pyruvate covalently bound through an ester to phosphopantothenoylcysteine decarboxylase which is then another example of a mammalian enzyme in which pyruvate is involved in a catalytic activity
The complex impact of cancer-related missense mutations on the stability and on the biophysical and biochemical properties of MAPK1 and MAPK3 somatic variants
No full textMitogen-activated protein kinases 1 and 3 (MAPK1 and MAPK3), also called extracellular regulated kinases (ERK2 and ERK1), are serine/threonine kinase activated downstream by the Ras/Raf/MEK/ERK signal transduction cascade that regulates a variety of cellular processes. A dysregulation of MAPK cascade is frequently associated to missense mutations on its protein components and may be related to many pathologies, including cancer. In this study we selected from COSMIC database a set of MAPK1 and MAPK3 somatic variants found in cancer tissues carrying missense mutations distributed all over the MAPK1 and MAPK3 sequences. The proteins were expressed as pure recombinant proteins, and their biochemical and biophysical properties have been studied in comparison with the wild type. The missense mutations lead to changes in the tertiary arrangements of all the variants. The thermodynamic stability of the wild type and variants has been investigated in the non-phosphorylated and in the phosphorylated form. Significant differences in the thermal stabilities of most of the variants have been observed, as well as changes in the catalytic efficiencies. The energetics of the catalytic reaction is affected for all the variants for both the MAPK proteins. The stability changes and the variation in the enzyme catalysis observed for most of MAPK1/3 variants suggest that a local change in a residue, distant from the catalytic site, may have long-distance effects that reflect globally on enzyme stability and functions
EXTREMELY THERMOSTABLE GLUTAMATE DEHYDROGENASE FROM THE HYPERTHERMOPHILIC ARCHAEBACTERIUM Pyrococcus furiosus
No full textThe hyperthermophilic archaebacterium Pyrococcus furiosus contains high levels of NAD(P)-dependent glutamate dehydrogenase activity. The enzyme could be involved in the first step of nitrogen metabolism, catalyzing the conversion of 2-oxoglutarate and ammonia to glutamate. The enzyme, purified to homogeneity, is a hexamer of 290 kDa (subunit mass 48 kDa). Isoelectric-focusing analysis of the purified enzyme showed a pI of 4.5. The enzyme shows strict specificity for 2-oxoglutarate and L-glutamate but utilizes both NADH and NADPH as cofactors. The purified enzyme reveals an outstanding thermal stability (the half-life for thermal inactivation at 100-degrees-C was 12 h), totally independent of enzyme concentration. P. furiosus glutamate dehydrogenase represents 20% of the total protein; this elevated concentration raises questions about the roles of this enzyme in the metabolism of P. furiosus
Refolding of glutamate dehydrogenase from Bacillus acidocaldarius after guanidinium chloride-induced unfolding
No full textI.F.= 0.79
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