increasing evidence suggests that in Amyotrophic Lateral Sclerosis (ALS) mutated RnA binding proteins acquire aberrant functions, leading to altered RNA metabolism with significant impact on encoded protein levels. Here, by taking advantage of a human induced pluripotent stem cell-based model, we aimed to gain insights on the impact of ALS mutant fUS on the motoneuron proteome. Label-free proteomics analysis by mass-spectrometry revealed upregulation of proteins involved in catabolic processes and oxidation-reduction, and downregulation of cytoskeletal proteins and factors directing neuron projection. Mechanistically, proteome alteration does not correlate with transcriptome changes. Rather, we observed a strong correlation with selective binding of mutant fUS to target mRNAs in their 3′UtR. novel validated targets, selectively bound by mutant fUS, include genes previously involved in familial or sporadic ALS, such as VCP, and regulators of membrane trafficking and cytoskeleton remodeling, such as ASAP1. These findings unveil a novel mechanism by which mutant fUS might intersect other pathogenic pathways in ALS patients' motoneurons. The motoneuron disease Amyotrophic Lateral Sclerosis (ALS) has been linked to mutations in several RNA binding proteins (RBPs) and altered RNA metabolism 1,2. ALS mutations affecting nuclear localization of the RBP FUS are regarded as a primary event, eventually leading to motoneuron death by unknown mechanisms 3,4. Accordingly, FUS mutations that cause higher levels of mislocalization in the cytoplasm (such as the P525L) are associated to more aggressive and juvenile ALS pathology 5. However, little is known about the effects of abnormal FUS accumulation in the cytoplasm on its RNA targets. A change in the translatome has been previously observed in neurons derived from mouse embryonic stem cells ectopically overexpressing human FUS-R495X protein, which is another mutant FUS mislocalized to the cytoplasm 6. Alteration of protein translation was also studied upon oxidative stress and ectopic expression of wild-type (WT) or R495X mutant FUS in neuroblastoma cells 7. However, overexpression of WT FUS at non-physiological levels is known to produce toxic effects per se 8. Moreover, since ALS specifically affects motoneurons 9 , disease-relevant targets might be missed in in vitro models based on non-motoneuronal cells. The effect of mutant FUS on the proteome of human motoneurons remains unexplored.

Sperm motility is the most important parameter involved in the fertilization process and it is strictly required for reproductive success. Although sperm movements are essential for the physiologic fertilization process, the data, deriving from studies focused on the research of altered cell pathways involved in asthenozoospermia, offer only limited information about the molecular mechanism underlying sperm motility. The aim of this study was to identify proteins involved in human sperm motility deficiency by using label-free mass-spectrometry liquid chromatography (LC−MS/MS). For this purpose, we selected sperm samples with three different classes of progressive motility: low, medium (asthenozoospermic samples) and high (normozoospermic samples). We found that several differential expressed proteins in asthenozoospermic samples were related to energetic metabolism, suggesting an interesting link between bioenergetics pathways and the regulation of sperm motility, necessary for the flagellum movement. Therefore, our results provide strong evidence that mass spectrometry-based proteomics represents an integrated approach to detect novel biochemical markers of sperm motility and quality with diagnostic relevance for male infertility and unravel the molecular etiology of idiopathic cases.

Physical exercise stimulates adult hippocampal neurogenesis and is considered a relevant strategy for preventing age-related cognitive decline in humans. The underlying mechanisms remains controversial. Here, we show that exercise increases proliferation of neural precursor cells (NPCs) of the mouse dentate gyrus (DG) via downregulation of microRNA 135a-5p (miR-135a). MiR-135a inhibition stimulates NPC proliferation leading to increased neurogenesis, but not astrogliogenesis, in DG of resting mice, and intriguingly it reactivates NPC proliferation in aged mice. We identify 17 proteins (11 putative targets) modulated by miR-135 in NPCs. Of note, inositol 1,4,5-trisphosphate (IP3) receptor 1 and inositol polyphosphate-4-phosphatase type I are among the modulated proteins, suggesting that IP3 signaling may act downstream miR-135. miR-135 is the first noncoding RNA essential modulator of the brain's response to physical exercise. Prospectively, the miR-135-IP3 axis might represent a novel target of therapeutic intervention to prevent pathological brain aging.

Cells respond to starvation by shutting down protein synthesis and by activating catabolic processes, including autophagy, to recycle nutrients. This two-pronged response is mediated by the integrated stress response (ISR) through phosphorylation of eIF2α, which represses protein translation, and by inhibition of mTORC1 signaling, which promotes autophagy also through a stress-responsive transcriptional program. Implementation of such a program, however, requires protein synthesis, thus conflicting with general repression of translation. How is this mismatch resolved? We found that the main regulator of the starvation-induced transcriptional program, TFEB, counteracts protein synthesis inhibition by directly activating expression of GADD34, a component of the protein phosphatase 1 complex that dephosphorylates eIF2α. We discovered that GADD34 plays an essential role in autophagy by tuning translation during starvation, thus enabling lysosomal biogenesis and a sustained autophagic flux. Hence, the TFEB-GADD34 axis integrates the mTORC1 and ISR pathways in response to starvation.

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