The nucleolar protein 2 gene encodes a protein specific for the nucleolus. It is assumed that it plays a role in the synthesis of ribosomes and regulation of the cell cycle. Due to its link to cell proliferation, higher expression of Nop2 indicates a worse tumor prognosis. In this work we used Nop2(gt1gaj) gene trap mouse strain. While lethality of homozygous animals suggested a vital role of this gene, heterozygous animals allowed the detection of expression of Nop2 in various tissues, including mouse brain. Histochemistry, immunohistochemistry and immunoelectron microscopy techniques, applied to a mature mouse brain, human brain and on mouse neural stem cells revealed expression of Nop2 in differentiating cells, including astrocytes, as well as in mature neurons. Nop2 was detected in various regions of mouse and human brain, mostly in large pyramidal neurons. In the human, Nop2 was strongly expressed in supragranular and infragranular layers of the somatosensory cortex and in layer III of the cingulate cortex. Also, Nop2 was detected in CA1 and the subiculum of the hippocampus. Subcellular analyses revealed predominant location of Nop2 within the dense fibrillar component of the nucleolus. To test if Nop2 expression correlates to cell proliferation occurring during tissue regeneration, we induced strokes in mice by middle cerebral artery occlusion. Two weeks after stroke, the number of Nop2/nestin double positive cells in the region affected by ischemia and the periventricular zone substantially increased. Our findings suggest a newly discovered role of Nop2 in both mature neurons and in cells possibly involved in the regeneration of nervous tissue.

Non-alcoholic fatty liver disease (NAFLD), the leading cause of chronic liver disease in Western countries, has been identified as a possible risk factor for COVID-19 severity. However, the immunological mechanisms by which NAFLD exacerbates COVID-19 remain unknown. Transforming growth factor-beta 1 (TGF-β1) has an important immunomodulatory and pro-fibrotic role, which has already been described in NAFLD. However, the role of TGF-β1 in COVID-19 remains unclear, and could also be the pathophysiology link between these two conditions. The aim of this case–control study was to analyze the expression of TGF-β1 in COVID-19 patients depending on the presence of NAFLD and COVID-19 severity. Serum TGF-β1 concentrations were measured in 60 hospitalized COVID-19 patients (30 with NAFLD). NAFLD was associated with higher serum TGF-β1 concentrations that increased with disease severity. Admission TGF-β1 concentrations showed good discriminative accuracy in predicting the development of critical disease and COVID-19 complications (need for advanced respiratory support, ICU admission, time to recovery, development of nosocomial infections and mortality). In conclusion, TGF-β1 could be an efficient biomarker for predicting COVID-19 severity and adverse outcomes in patients with NAFLD.