👤 Alessandro Maloberti

Mitogen-activated protein kinase (MAPK) phosphatases [MKPs, also known as dual-specificity phosphatases (DUSPs)] regulate MAPKs -key mediators of cellular processes such as proliferation, differentiation, and survival- by dephosphorylating the threonine and tyrosine residues required for MAPK activation. MKP-3/DUSP6 is an ERK-selective phosphatase that has also been reported to regulate the transcription factor FOXO1. The full-length MKP-3 transcript has been shown to encode the MKP-3L protein, whereas alternative splicing gives rise to the shorter isoform MKP-3S. However, the available information regarding the functional differences between these variants is limited. By combining biochemical and bioinformatic approaches, we demonstrate that these isoforms differ significantly in subcellular localization and enzymatic activity. Structural analysis and molecular docking reveal that while MKP-3S retains functional binding domains and recognizes ERK2 similarly to the full-length isoform. However, the absence of critical catalytic motifs in MKP-3S leads to a structural uncoupling where the protein retains its ability to bind ERK2 but fails to induce dephosphorylation, suggesting a non-canonical role as a molecular scaffold. The results obtained demonstrate significant variations in subcellular localization, enzymatic activity, and the capacity to modulate FOXO1 transcriptional activity. This, in turn, affects the expression of genes such as p21. In conclusion, the findings indicate that MKP-3 variants exhibit distinct functional behaviours, which may result in differential regulation of a wide range of cellular processes. Show less

Testicular adult granulosa cell tumors (AGCTs) are rare and show several clinical, pathological, and molecular differences with their ovarian counterparts. FOXL2 p.Cys134Trp, the ubiquitous molecular driver of ovarian AGCTs, is infrequent (~ 7%) in testicular AGCTs. Recently, FGFR1 hotspot mutations were reported as a potentially "alternative molecular driver" in FOXL2-wild type (WT) ovarian AGCTs. A systematic assessment of FGFR1 status has not been performed in testicular AGCTs. Recently, our group analyzed a series of twenty testicular AGCTs using two NGS panels that lacked coverage of FGFR1. Among twelve cases analyzed successfully, none harbored pathogenic FOXL2 variants. In this study, we reassessed the tumors from our prior series with an NGS panel that covers FGFR1. Among the 14 tumors (70%) that were sequenced successfully, none harbored pathogenic FGFR1 variants. Considering the AGCTs assessed in this study and those previously reported in the literature, none of the 24 tumors analyzed to date have shown pathogenic FGFR1 variants. The present study reinforces the concept that testicular sex cord-stromal tumors classified as AGCTs are different from ovarian counterparts. Show less

Elevated lipoprotein(a) [Lp(a)] levels have been strongly related to cardiovascular (CV) risk. However, its association with Hypertension Mediated Organ Damage (HMOD) and CV events in the primary prevention setting remains unclear. To evaluate in these patients, the correlation between Lp(a) levels and: (i) heart, vessels and kidney HMOD and; (ii) CV events and all-cause mortality in a primary prevention setting. 747 low CV risk subjects were recruited between 2009 and 2014. HMOD was assessed through Pulse Wave Velocity, carotid Intima-Media Thickness (IMT), presence of carotid plaques, Left Ventricular Hypertrophy (LVH) and Ejection Fraction and glomerular filtration rate. All-cause mortality and CV events up to 2021 were retrieved by electronic health records, for a median follow-up time of 10 years (I-III quartiles 9.6-11.1). Mean age was 50.8 ± 13.0 years and 63.5% of the subjects were men. The prevalence of hypertension was 37.9%, dyslipidemia 67.2%, smoking 17.8%, and diabetes mellitus 8.7%. Median Lp(a) value was 17 mg/dL (5.9-56.0), and 26.5% of patients had values above 50 mg/dL. Regarding HMOD, 10.3% subjects had arterial stiffness, 7.2% increased IMT, 19.8% carotid plaques while only 0.7% had LVH. No significant correlation was found between Lp(a) levels and indices of subclinical HMOD. Furthermore, no relationship was found between CV events and all-cause mortality and Lp(a) levels. In this primary prevention cohort, elevated Lp(a) levels were not associated with significant structural damage to the heart, carotid arteries, or increased aortic stiffness and were not associated with CV events and all-cause mortality. Show less

Molecular analysis of Each participating institution was requested to apply its own diagnostic testing strategy on 8 sections obtained from artificial reference specimens built to harbor Overall, cell resuspension yielded higher amounts of DNA and RNA (SNU16 61.5 ng/µl, 38100.0 pg/µl; RT112 118.0/µl, 2140.0 pg/µl, respectively) in comparison with SNU16+ RT112 mixing cell block (0.7 ng/µl DNA and 412.0 pg/µl RNA). Moreover, FFPE samples showed a higher fragmentation index (DIN 1.2 and RIN not calculated) compared with cell line resuspension (DIN 2.2 and 9.5 for SNU16 and RT112; RIN 3.9 and 6.8 for SNU16 and RT112). All participating institutions identified NGS represents the most suitable approach in molecular profiling of Show less

MAPK phosphatases (MKP) downregulate the activity of mitogen-activated protein kinases (MAPK), such as ERK1/2, and modulate the processes regulated by these kinases. ERK1/2 participate in a wide range of processes including tissue-specific hormone-stimulated steroidogenesis. H295R cells are a suitable model for the study of human adrenal cortex functions, particularly steroid synthesis, and respond to angiotensin II (Ang II) triggering ERK1/2 phosphorylation in a transient fashion. MKP-3 dephosphorylates ERK1/2 and, as recently reported, forkhead box protein 1 (FOXO1). Here, we analyzed MKP-3 expression in H295R cells and its putative regulation by Ang II. Results showed the expression of MKP-3 full length (L) and a short splice variant (S), and the upregulation of both isoforms by Ang II. L and S messenger and protein levels increased 30 min after Ang II stimulation and declined over the next 3 h, a temporal frame compatible with ERK1/2 dephosphorylation. In addition, FOXO1 activation is known to include its dephosphorylation and nuclear translocation. Therefore, we analyzed the effect of Ang II on FOXO1 modulation. Ang II induced FOXO1 transient phosphorylation and translocation and also the induction of p21, a FOXO1-dependent gene, whereas MKP-3 knock-down reduced both FOXO1 translocation and p21 induction. These data suggest that, through MKP-3, Ang II counteracts its own effects on ERK1/2 activity and also triggers the activation of FOXO-1 and the induction of cell cycle inhibitor p21. Taken together, the current findings reveal the participation of MKP-3 not only in turn-off but also in turn-on signals which control important cellular processes. Show less

Treatment of overt form of hypertrophic cardiomyopathy (HCM) is often unsuccessful. Efforts are focused on a possible early identification in order to prevent or delaying the development of hypertrophy. Our aim was to find an echocardiographic marker able to distinguish mutation carriers without left ventricular hypertrophy (LVH) from healthy subjects. We evaluated 28 patients, members of eight families. Three types of mutation were recognized: MYBPC3 (five families), MYH7 (two families) and TNNT2 (one family). According to genetic (G) and phenotypic (Ph) features, patients were divided in three groups: Group A (10 patients), mutation carriers with LVH (G+/Ph+); Group B (9 patients), mutation carriers without LVH (G+/Ph-); Group C (9 patients), healthy subjects (G-/Ph-). Echocardiography examination was performed acquiring standard 2D, DTI and 2D-strain imaging. Global longitudinal strain (GLS) and global radial strain (GRS) at basal and mid-level were measured. GRS was significantly different between group B and C at basal level (32.18% ± 9.6 vs. 44.59% ± 12.67 respectively; p-value < 0.0001). In basal posterior and basal inferior segments this difference was particularly evident. ROC curves showed for both the involved segments good AUCs (0.931 and 0.861 for basal posterior and inferior GRS respectively) with the best predictive cut-off for basal posterior GRS at 43.65%, while it was 38.4% for basal inferior GRS. Conversely, GLS values were similar in the three group. 2D longitudinal strain is a valid technique to study HCM. Radial strain and particularly basal posterior and inferior segmental reduction could be able to identify mutation carriers in a pre-clinical phase of disease. Show less