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Introduction: β-thalassemia is caused by autosomal mutations in the β-globin gene, which induce the absence or low-level synthesis of β-globin in erythroid cells. It is widely accepted that a high production of fetal hemoglobin (HbF) is beneficial for patients with β-thalassemia. Sirolimus, also known as rapamycin, is a lipophilic macrolide isolated from a strain of Streptomyces hygroscopicusthat serves as a strong HbF inducer in vitroand in vivo. In this study, we report biochemical, molecular, and clinical results of a sirolimus-based NCT03877809 clinical trial (a personalized medicine approach for β-thalassemia transfusion-dependent patients: testing sirolimus in a first pilot clinical trial, Sirthalaclin).Methods: Accumulation of γ-globin mRNA was analyzed using reverse-transcription quantitative polymerase chain reaction (PCR), while the hemoglobin pattern was analyzed using high-performance liquid chromatography (HPLC). The immunophenotype was analyzed using a fluorescence-activated cell sorter (FACS), with antibodies against CD3, CD4, CD8, CD14, CD19, CD25 (for analysis of peripheral blood mononuclear cells), or CD71 and CD235a (for analysis of in vitrocultured erythroid precursors).Results: The results were obtained in eight patients with the β+/β+and β+/β0genotypes, who were treated with a starting dosage of 1 mg/day sirolimus for 24–48 weeks. The first finding of this study was that the expression of γ-globin mRNA increased in the blood and erythroid precursor cells isolated from β-thalassemia patients treated with low-dose sirolimus. This trial also led to the important finding that sirolimus influences erythropoiesis and reduces biochemical markers associated with ineffective erythropoiesis (excess free α-globin chains, bilirubin, soluble transferrin receptor, and ferritin). A decrease in the transfusion demand index was observed in most (7/8) of the patients. The drug was well tolerated, with minor effects on the immunophenotype, and an only side effect of frequently occurring stomatitis.Conclusion: The data obtained indicate that low doses of sirolimus modify hematopoiesis and induce increased expression of γ-globin genes in a subset of patients with β-thalassemia. Further clinical trials are warranted, possibly including testing of the drug in patients with less severe forms of the disease and exploring combination therapies.

We have recently shown that open reading frame Rv1086 of the Mycobacterium tuberculosisH37Rv genome sequence encodes a unique isoprenyl diphosphate synthase. The product of this enzyme, ω,E,Z-farnesyl diphosphate, is an intermediate for the synthesis of decaprenyl phosphate, which has a central role in the biosynthesis of most features of the mycobacterial cell wall, including peptidoglycan, arabinan, linker unit galactan, and lipoarabinomannan. We have now purified Z-farnesyl diphosphate synthase to near homogeneity using a novel mycobacterial expression system.Z-Farnesyl diphosphate synthase catalyzed the addition of isopentenyl diphosphate to ω,E-geranyl diphosphate or ω,Z-neryl diphosphate yieldingω,E,Z-farnesyl diphosphate andω,Z,Z-farnesyl diphosphate, respectively. The enzyme has an absolute requirement for a divalent cation, an optimal pH range of 7–8, and Kmvalues of 124 µmfor isopentenyl diphosphate, 38 µmfor geranyl diphosphate, and 16 µmfor neryl diphosphate. Inhibitors of the Z-farnesyl diphosphate synthase were designed and chemically synthesized as stable analogs ofω,E-geranyl diphosphate in which the labile diphosphate moiety was replaced with stable moieties. Studies with these compounds revealed that the active site of Z-farnesyl diphosphate synthase differs substantially from E-farnesyl diphosphate synthase from pig brain (Sus scrofa).

The synthesis of the two enantiomers of 3-(3,4-dimethylphenyl)-1-propylpiperidine 1, a potent and selective D4 dopaminergic ligand, was performed. The 3-(3,4-dimethylphenyl)-1-propylpiperidine with the Rconfiguration showed an affinity for the D4 receptors 6-fold higher than the corresponding enantiomer with the Sconfiguration. Furthermore, the (R)-1enantiomer proved to be highly selective for D4 receptors with respect to D2–D3 receptors, with a Kiratio higher than 25,000, while the (S)-1enantiomer was about 100-fold less selective than the (R)-1one

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".