👤 Takashi Sakuma

Nucleoporins are increasingly recognized as tissue-specific regulators beyond their structural roles in the nuclear pore complex. Here, we identify nucleoporin Nup358 as a critical repressor of Wnt signaling required for intestinal epithelium integrity. Ablation of Nup358 in adult mice causes a catastrophic loss of crypt-villus architecture and disrupts the intestinal epithelial layer. Notably, while the intestinal stem cell (ISC) pool remains stable, the transit-amplifying (TA) progenitor compartment is depleted. Mechanistically, we show that the interaction of Nup358 with Dvl1 through its N-terminal domain inhibits Dvl1 spontaneous phase separation. In the absence of Nup358, Dvl1 biomolecular condensates promote Tankyrase-mediated degradation of Axin1, leading to the constitutive stabilization of β-catenin and ligand-independent Wnt activation, negatively impacting cell differentiation and TA progenitor survival. Our results demonstrate that Nup358 acts as a molecular safeguard that dampens Wnt signaling levels in intestinal crypts. By preventing Dvl1-mediated Wnt signal amplification, Nup358 allows ISCs to transition into the TA compartment and initiate the differentiation programs essential for intestinal homeostasis. Show less

Fatty liver index (FLI) calculated by using body mass index, waist circumference and levels of triglycerides and γ-glutamyl transpeptidase is a noninvasive biomarker for diagnosis of metabolic dysfunction-associated steatotic liver disease (MASLD), which is one of the high-risk conditions of atherosclerotic cardiovascular diseases. To compare the effects of pemafibrate and omega-3 fatty acid ethyl on FLI, we conducted a sub-analysis study of the Pemafibrate Reduction of triglyceride-rich lipoproteins compared with Omega-3 fatty acid ethyl for Unmet needs in Dyslipidemic patients on target to apoB-48 (PROUD48) study. 57 participants in the pemafibrate 0.4 mg per day treatment group (PEMA, men/women: 37/20, mean 64 years) and 60 participants in the omega-3 fatty acid ethyl 4 g per day treatment group (OMEGA-3, men/women: 35/25, mean 63 years) in the PROUD48 study were included in the present study. Changes in FLI and prevalence of MASLD from baseline to week 16 in PEMA and OMEGA-3 were investigated. Median FLI was significantly decreased by both PEMA (69.7 to 47.6, Pemafibrate is superior to omega-3 fatty acid ethyl in lowering effects of FLI and MASLD in patients with dyslipidemia receiving statin treatment, suggesting that pemafibrate is a beneficial agent for hypertriglyceridemia and reduction of the risk for MASLD. Show less

Histiocytic sarcoma (HS) is an incurable aggressive tumor, and no consensus has been made on the treatment due to its rare occurrence. Since dogs spontaneously develop the disease and several cell lines are available, they have been advocated as translational animal models. In the present study, therefore, we explored gene mutations and aberrant molecular pathways in canine HS by next generation sequencing to identify molecular targets for treatment. Whole exome sequencing and RNA-sequencing revealed gene mutations related to receptor tyrosine kinase pathways and activation of ERK1/2, PI3K-AKT, and STAT3 pathways. Analysis by quantitative PCR and immunohistochemistry revealed that fibroblast growth factor receptor 1 (FGFR1) is over-expressed. Moreover, activation of ERK and Akt signaling were confirmed in all HS cell lines, and FGFR1 inhibitors showed dose-dependent growth inhibitory effects in two of the twelve canine HS cell lines. The findings obtained in the present study indicated that ERK and Akt signaling were activated in canine HS and drugs targeting FGFR1 might be effective in part of the cases. The present study provides translational evidence that leads to establishment of novel therapeutic strategies targeting ERK and Akt signaling in HS patients. Show less