In mammals, members of the transforming growth factor-beta (TGF-β) superfamily are known to have key roles in the regulation of follicular growth and development. The aim of the study was to evaluate the expression of TGF-β superfamily growth factors, their receptors, downstream SMAD signalling molecules and TGF-β/bone morphogenetic protein (BMP) antagonists during early human folliculogenesis. Human pre-antral follicles were enzymatically isolated from surplus ovarian tissue obtained from women having ovarian cortical tissue frozen for fertility preservation. A total of 348 human pre-antral follicles, ranging from 40 to 200 µm in diameter, were isolated from ovarian tissue obtained from 15 women, aged 24–34 years. Isolated pre-antral follicles were grouped according to diameter in five size-matched populations spanning the primordial, primary and secondary stage follicles and analysed by whole-genome microarray analysis. Selected proteins/genes were analysed by immunocytochemistry and quantitative RT–PCR. TGF-β superfamily genes with overall highest mRNA expressions levels included growth differentiation factors 9 (GDF9), BMP15, BMP6, BMP-receptor-2 (BMPR2), anti-Müllerian hormone receptor 2 (AMHR2), TGFβR3, inhibin-α (INHA) and intracellular SMAD3 and SMAD4. Moreover, genes which were differentially expressed from the primordial to the late secondary stage follicles included GDF9, BMP15, AMH, INHBB, TGFβR3, SMAD4 and antagonists Follistatin (FST) and GREM1. Collectively, these data indicate that the active TGF-β superfamily pathways in early human folliculogenesis consist of primarily GDF9 combined with possible synergistic effects of BMP15 through the BMPR2 and intracellular activation of SMAD3 and SMAD4, and that AMH and INHBB are engaged in intrafollicular events from the onset of follicular growth. Moreover, the presence of multiple TGF-β/BMP antagonists imply that certain growth factors are subjected to local regulation on different levels that address another important level of intraovarian regulation of follicle development in humans.

RNase T2 enzymes are produced by a wide range of organisms and have been implicated to function in diverse cellular processes, including stress-induced anticodon loop cleavage of mature tRNAs to generate tRNA halves. Here we describe a family of eight RNase T2 genes (RNT2A–RNT2H) in the ciliate Tetrahymena thermophila. We constructed strains lacking individual or combinations of these RNT2 genes that were viable but had distinct cellular and molecular phenotypes. In strains lacking only one Rnt2 protein or lacking a subfamily of three catalytically inactive Rnt2 proteins, starvation-induced tRNA fragments continued to accumulate, with only a minor change in fragment profile in one strain. We therefore generated strains lacking pairwise combinations of the top three candidates for Rnt2 tRNases. Each of these strains showed a distinct starvation-specific profile of tRNA and rRNA fragment accumulation. These results, the delineation of a broadened range of conditions that induce the accumulation of tRNA halves, and the demonstration of a predominantly ribonucleoprotein-free state of tRNA halves in cell extract suggest that ciliate tRNA halves are degradation intermediates in an autophagy pathway induced by growth arrest that functions to recycle idle protein synthesis machinery.

Novel therapies for the treatment of acute myeloid leukemia (AML) are urgently needed, because current treatments do not cure most patients with AML. We report a domain-focused, kinome-wide CRISPR-Cas9 screening that identified protein kinase targets for the treatment of AML, which led to the identification of Rio-kinase 2 (RIOK2) as a potential novel target. Loss of RIOK2 led to a decrease in protein synthesis and to ribosomal instability followed by apoptosis in leukemic cells, but not in fibroblasts. Moreover, the ATPase function of RIOK2 was necessary for cell survival. When a small-molecule inhibitor was used, pharmacological inhibition of RIOK2 similarly led to loss of protein synthesis and apoptosis and affected leukemic cell growth in vivo. Our results provide proof of concept for targeting RIOK2 as a potential treatment of patients with AML.

Twenty new compounds, targeting CYP17A1, were synthesized, based on our previous work on a benzimidazole scaffold, and their biological activity evaluated. Inhibition of CYP17A1 is an important modality in the treatment of prostate cancer, which remains the most abundant cancer type in men. The biological assessment included CYP17A1 hydroxylase and lyase inhibition, CYP3A4 and P450 oxidoreductase (POR) inhibition, as well as antiproliferative activity in PC3 prostate cancer cells. The most potent compounds were selected for further analyses including in silico modeling. This combined effort resulted in a compound (comp 2, IC₅₀ 1.2 µM, in CYP17A1) with a potency comparable to abiraterone and selectivity towards the other targets tested. In addition, the data provided an understanding of the structure–activity relationship of this novel non-steroidal compound class.

Ribosomopathies constitute a range of disorders associated with defective protein synthesis mainly affecting hematopoietic stem cells (HSCs) and erythroid development. Here, we demonstrate that deletion of poly-pyrimidine-tract-binding protein 1 (PTBP1) in the hematopoietic compartment leads to the development of a ribosomopathy-like condition. Specifically, loss of PTBP1 is associated with decreases in HSC self-renewal, erythroid differentiation, and protein synthesis. Consistent with its function as a splicing regulator, PTBP1 deficiency results in splicing defects in hundreds of genes, and we demonstrate that the up-regulation of a specific isoform of CDC42 partly mimics the protein-synthesis defect associated with loss of PTBP1. Furthermore, PTBP1 deficiency is associated with a marked defect in ribosome biogenesis and a selective reduction in the translation of mRNAs encoding ribosomal proteins. Collectively, this work identifies PTBP1 as a key integrator of ribosomal functions and highlights the broad functional repertoire of RNA-binding proteins.