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IntroductionShwachman-Diamond Syndrome (SDS) is a rare bone marrow (BM) failure disorder. SDS BM biopsies show tortuous and collapsed vessels, highlighting angiogenic abnormalities. Our group previously demonstrated that SDS BM mesenchymal stromal cells (MSCs) have in vitroand in vivoimpaired angiogenic potential compared to healthy donors (HD)-MSCs.

One of the clinical features of cystic fibrosis (CF) is a deep inflammatory process, which is characterized by production and release of cytokines and chemokines, among which interleukin 8 (IL-8) represents one of the most important. Accordingly, there is a growing interest in developing therapies against CF to reduce the excessive inflammatory response in the airways of CF patients. Since transcription factor NF-kappaB plays a critical role in IL-8 expression, the transcription factor decoy (TFD) strategy might be of interest. In order to demonstrate that TFD against NF-kappaB interferes with the NF-kappaB pathway we proved, by chromatin immunoprecipitation (ChIP) that treatment with TFD oligodeoxyribonucleotides of cystic fibrosis IB3–1 cells infected with Pseudomonas aeruginosaleads to a decrease occupancy of the Il-8 gene promoter by NF-kappaB factors. In order to develop more stable therapeutic molecules, peptide nucleic acids (PNAs) based agents were considered. In this respect PNA-DNA-PNA (PDP) chimeras are molecules of great interest from several points of view: (1) they can be complexed with liposomes and microspheres; (2) they are resistant to DNases, serum and cytoplasmic extracts; (3) they are potent decoy molecules. By using electrophoretic mobility shift assay and RT-PCR analysis we have demonstrated that (1) the effects of PDP/PDP NF-kappaB decoy chimera on accumulation of pro-inflammatory mRNAs in P.aeruginosainfected IB3–1 cells reproduce that of decoy oligonucleotides; in particular (2) the PDP/PDP chimera is a strong inhibitor of IL-8 gene expression; (3) the effect of PDP/PDP chimeras, unlike those of ODN-based decoys, are observed even in the absence of protection with lipofectamine. These informations are of great impact, in our opinion, for the development of stable molecules to be used in non-viral gene therapy of cystic fibrosis.

In the Shwachman-Diamond syndrome (SDS), mutations of the gene encoding for the SBDS protein causes several hematological disorders, including neutropenia and myelodysplastic syndrome (MDS), with high risk of acute myeloid leukemia (AML).MicroRNAs (miRNAs) are small noncoding RNAs regulating gene expression by sequence-selective targeting of mRNAs, leading to translational repression or mRNA degradation. Low miRNA expression is associated with the accumulation of target mRNAs; high miRNA content causes low expression of target mRNAs. In almost all hematological disorders microRNAs were found dysregulated, and often these alterations of miRNAlevels are associated with the phenotype of the disease and tumor onset and progression.

Bezzerri: Marco Cipolli, Valentino Bezzerri, Baroukh Maurice Assael: Patents & Royalties: WO2018/050706 A1 "Method of treatment of Shwachman-Diamond syndrome". Cipolli:Marco Cipolli, Valentino Bezzerri, Baroukh Maurice Assael: Patents & Royalties: WO2018/050706 A1 "Method of treatment of Shwachman-Diamond syndrome".

Bezzerri: Marco Cipolli, Valentino Bezzerri, Baroukh Maurice Assael: Patents & Royalties: WO2018/050706 A1 "Method of treatment of Shwachman-Diamond syndrome". Cipolli:Marco Cipolli, Valentino Bezzerri, Baroukh Maurice Assael: Patents & Royalties: WO2018/050706 A1 "Method of treatment of Shwachman-Diamond syndrome".

No relevant conflicts of interest to declare.

Shwachman-Diamond syndrome (SDS) is a rare autosomal recessive disease which affects 1/168,000 newborns in Italy with a mean of 3.0 new cases/year. SDS is caused by mutations in the Shwachman-Bodian-Diamond syndrome (SBDS) gene, which encodes for the homonymous protein SBDS, whose exact function is still unknown. SBDS protein has been reported to play a role in eukaryotic ribosome biogenesis. Thus, SDS is considered a ribosomopathy. The pathology is characterized by multiple-organ impairment involving bone marrow failure, exocrine pancreatic insufficiency, skeletal malformations, hepatic and cognitive disorders. Neutropenia and impaired neutrophil chemotaxis, which in turn cause recurrent infections, are reported in young children. Furthermore, 15-20% of SDS patients develop myelodysplastic syndrome (MDS), with increased risk of acute myeloid leukemia (AML) progression, which represent the main cause of mortality. However, the exact pathologic mechanism whereby loss of SDBS function could lead to the specific SDS hematological issues remains unclear. We recently reported, for the first time to the best of our knowledge, that the mammalian Target of Rapamycin (mTOR) and Signal Transducer and Activator of Transcription (STAT)-3 pathways are hyper-activated in B cells, PMNs and, mostly, in monocytes obtained from SDS patients (Bezzerri V et al, Sci Rep2016, in press). Since mTOR and STAT3 activation are associated with neutrophil development and AML, this finding could at least partially explain the onset of the hematological issues. Here we show a further Phospho flow analysis of mTOR and STAT3 pathways activation in otherlymphocytes subsets,in particular in CD8+/CD4+ T cells and NK cells obtained from five SDS patients. We found that STAT3 S727 is the most phosphorylated site in CD8+ and CD4+ T cells (more than twice than the healthy control cells, each). Furthermore, mTOR (S2448) is hyper-phosphorylated in CD8+ and CD4+ T cells derived from SDS patients. Median fluorescence intensity shifted from 220 ± 25 (healthy controls) to 405 ± 29 (SDS patients) in CD8+ T cells and from 350 ± 132 (healthy controls) to 590 ± 150 (SDS patients) in CD4+ T cells, similarly to results obtained from Monocytes and B cells. NK seems to be less responsive to mTOR/STAT3 activation than B and T cells. Importantly, mTOR inhibitor rapamycin is able to reduce both mTOR and STAT3 activation, with different efficacy, in a cell type-dependent manner. In particular, rapamycin strongly reduces both mTOR and STAT3 S727 phosphorylation in CD8+ and CD4+ T cells. Thus, these results suggest a role of mTOR/STAT3 pathways in both myeloid and lymphoid lineages of SDS blood cells. Since several drugs approved by FDA and EMA targeting the JAK-STAT and mTOR pathways have been currently evaluated for the treatment of different forms of hematological malignancies, this work could open a wider scenario into the current SDS therapeutic approaches.