Pietro Salvatore Carollo

Nonsense mutations affect about 11% of patients with Cystic Fibrosis and produce a premature termination codon in Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) mRNA causing early termination of the polypeptide translation. A potential therapy for nonsense mutations allows small molecules to overcome the premature termination codon (PTC) by a readthrough mechanism leading to the synthesis of a complete CFTR protein. However, the efficiency of the readthrough molecules is limited by a quality control cellular pathway known as Nonsense-mediated mRNA Decay (NMD). This pathway provides the degradation of the mRNA harboring a premature termination codon, to prevent the production of altered polypeptides. In contrast, the activity of this pathway interferes with the effectiveness of the readthrough drugs, limiting the CFTR mRNA amount to the rescue. In this work, we reduced the activity of the NMD pathway, silencing the Upf1 protein, one of the main components of the pathway. Our strategy was to increase the amount of the mRNA target to improve the efficiency of readthrough of TRIDs (Translational Readthrough Inducing Drugs) molecules in cells that ectopically express the W1282X-CFTR mRNA. The reduction of the Upf1 expression/activity was correlated with the increase of the efficiency of readthrough and so the increase of CFTR protein rescue.

Nonsense mutations cause several genetic diseases such as cystic fibrosis, Duchenne muscular dystrophy, β-thalassemia, and Shwachman–Diamond syndrome. These mutations induce the formation of a premature termination codon (PTC) inside the mRNA sequence, resulting in the synthesis of truncated polypeptides. Nonsense suppression therapy mediated by translational readthrough-inducing drugs (TRIDs) is a promising approach to correct these genetic defects. TRIDs generate a ribosome miscoding of the PTC named “translational readthrough” and restore the synthesis of full-length and potentially functional proteins. The new oxadiazole-core TRIDs NV848, NV914, and NV930 (NV) showed translational readthrough activity in nonsense-related in vitro systems. In this work, the possible off-target effect of NV molecules on natural termination codons (NTCs) was investigated. Two different in vitro approaches were used to assess if the NV molecule treatment induces NTC readthrough: (1) a study of the translational-induced p53 molecular weight and functionality; (2) the evaluation of two housekeeping proteins’ (Cys-C and β2M) molecular weights. Our results showed that the treatment with NV848, NV914, or NV930 did not induce any translation alterations in both experimental systems. The data suggested that NV molecules have a specific action for the PTCs and an undetectable effect on the NTCs.

Nonsense mutations cause several genetic diseases such as Cystic fibrosis, Duchenne muscular dystrophy, β-thalassemia, and Shwachman-Diamond syndrome. These mutations induce the formation of a premature termination codon (PTC) inside the mRNA sequence that leads to the aberrant translation, resulting in the synthesis of truncated polypeptides. Nonsense suppression therapy mediated by translational readthrough-inducing drugs (TRIDs) is a promising approach to correct these genetic defects. TRIDs generate a ribosome miscoding of the PTC named “translational readthrough” and restore the synthesis of full-length and potentially functional protein. The new oxadiazole-core TRIDs NV848, NV914, and NV930 showed translational readthrough activity in nonsense-related in vitro systems. In this work, the possible off-target effect of NV molecules on natural termination codons (NTCs) was investigated. Two different in vitro approaches were used to assess if the NV molecules treatment induce NTCs readthrough: 1) A study of translational induced p53 molecular weight and functionality; 2) the evaluation of two housekeeping proteins (Cys-C and β2M) molecular weights. Our results showed that the treatment with NV848, NV914, or NV930 do not induce any translation alterations in both experimental systems. Data suggested that NV molecules have a specific action for the PTCs and an undetectable effect on the NTCs.

Cystic Fibrosis (CF) is an autosomal recessive genetic disease caused by mutations in the CFTR gene, coding for the CFTR chloride channel. About 10% of the CFTR gene mutations are “stop” mutations that generate a premature termination codon (PTC), thus synthesizing a truncated CFTR protein. A way to bypass PTC relies on ribosome readthrough, which is the ribosome’s capacity to skip a PTC, thus generating a full-length protein. “TRIDs” are molecules exerting ribosome readthrough; for some, the mechanism of action is still under debate. We investigate a possible mechanism of action (MOA) by which our recently synthesized TRIDs, namely NV848, NV914, and NV930, could exert their readthrough activity by in silico analysis and in vitro studies. Our results suggest a likely inhibition of FTSJ1, a tryptophan tRNA-specific 2′-O-methyltransferase.

During embryonic development, stem cells undergo the differentiation process so that they can specialize for different functions within the organism. Complex programs of gene transcription are crucial for this process to happen. Epigenetic modifications and the architecture of chromatin in the nucleus, through the formation of specific regions of active as well as inactive chromatin, allow the coordinated regulation of the genes for each cell fate. In this mini-review, we discuss the current knowledge regarding the regulation of three-dimensional chromatin structure during neuronal differentiation. We also focus on the role the nuclear lamina plays in neurogenesis to ensure the tethering of the chromatin to the nuclear envelope.

During embryonic development stem cells undergo the differentiation process so that they can specialise for different functions within the organism. Complex programs of gene transcription are crucial for this process to happen. Epigenetic modifications and the architecture of chromatin in the nucleus, by the formation of specific regions of active as well as inactive chromatin, allow the coordinated regulation of the genes for each cell fate. In this mini review, we discuss the current knowledge regarding the regulation of three-dimensional chromatin structure during neuronal differentiation. We also focus on the role played in neurogenesis by the nuclear lamina that ensures the tethering of the chromatin to the nuclear envelope.

Cystic Fibrosis (CF) is an autosomal recessive genetic disease caused by mutations in the CFTR gene, coding for the CFTR chloride channel. About 10% of the CFTR gene mutations are "stop" mutations, which generate a Premature Termination Codon (PTC), thus synthesizing a truncated CFTR protein. A way to bypass PTC relies on ribosome readthrough, which is the ribosome’s capacity to skip a PTC, thus generating a full-length protein. “TRIDs” are molecules exerting ribosome readthrough; for some, the mechanism of action is still under debate. We investigate a possible mechanism of action (MOA) by which our recently synthesized TRIDs, namely NV848, NV914, and NV930, could exert their readthrough activity by in silico analysis and in vitro studies. Our results suggest a likely inhibition of FTSJ1, a tryptophan tRNA-specific 2’-O-methyltransferase.

Background: Induced senescence could be exploited to selectively counteract the proliferation of cancer cells and target them for senolysis. We examined the cellular senescence induced by curcumin and whether it could be targeted by fisetin and quercetin, flavonoids with senolytic activity. Methods: Cell-cycle profiles, chromosome number and structure, and heterochromatin markers were evaluated via flow cytometry, metaphase spreads, and immunofluorescence, respectively. The activation of p21^waf1/cip1 was assessed via RT-qPCR and immunoblotting. Senescent cells were detected via SA-β-Galactosidase staining. Results: We report that curcumin treatment specifically triggers senescence in cancer cells by inducing mitotic slippage and DNA damage. We show that curcumin-induced senescence is p21^waf1/cip1-dependent and characterized by heterochromatin loss. Finally, we found that flavonoids clear curcumin-induced senescent cancer cells. Conclusions: Our findings expand the characterization of curcumin-induced cellular senescence in cancer cells and lay the foundation for the combination of curcumin and flavonoids as a possible anti-cancer therapy.