Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized by amyloid-β (Aβ) peptide accumulation, leading to neuroinflammation and neurodegeneration. In early AD stages, neurodegeneration of basal forebrain cholinergic neurons occurs. Microglia, which are brain immune cells, contribute to Aβ clearance and neuroinflammation. This study investigated the therapeutic effects of PNU282987, a selective full agonist of α7 nicotinic acetylcholine receptor (nAChR), using human models of microglia (hiMacs) and basal forebrain cholinergic neurons (hiBFChNs), both differentiated from human induced pluripotent stem cells (hiPSCs). Our findings indicated that PNU282987 markedly enhanced Aβ phagocytosis by microglia and extracellular Aβ clearance. Furthermore, PNU282987 injection reduced Aβ accumulation in the brain of a mouse model. Treatment of hiMacs with PNU282987 upregulated the expressions of efferocytosis-related genes, such as ASAP2, OSM, and THBD. Efferocytosis-like activation by PNU282987 in hiMacs was further suggested by an increased release of the anti-inflammatory cytokine interleukin-10 (IL-10), along with suppression of the pro-inflammatory cytokine IL-1β produced from microglia with Aβ treatment. This indicates a transformation from Aβ-induced inflammatory phagocytosis to an efferocytosis-like anti-inflammatory phagocytosis. PNU282987 also exerted direct neuroprotective effects on hiBFChNs against Aβ and tumor necrosis factor-α. Furthermore, PNU282987 changed the extracellular contents released from Aβ-treated hiMacs and attenuated the neurotoxicity. These results suggest that α7 nAChR stimulation by PNU282987 enhances the therapeutic effects against AD by promoting Aβ clearance with anti-neuroinflammatory regulation in the microglia and providing direct protection to neurons, thereby addressing the inflammatory and neurodegenerative aspects of AD.

In this study, to identify novel compounds that inhibit severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replication by targeting its protease, we screened an U.S. Food and Drug Administration (FDA)-approved drug library to determine their effects on SARS-CoV-2 3CL protease (3CL^pro) activity using a cellular- and green fluorescent protein (GFP) reporter-based 3CL^pro assay, called the FlipGFP-3CL^pro assay. Among the hit compounds, 5 compounds (auranofin, endoxifen, netupitant, pimozide, and regorafenib) were selected for further analysis. We found that 3 compounds (auranofin, endoxifen, and pimozide) showed dose-dependent inhibition of 3CL^pro activity using both the FlipGFP-3CL^pro assay and fluorescence-based in vitro 3CL^pro assays. We then tested the effect of these compounds on SARS-CoV-2 replication in cultured cells and found that all 5 compounds inhibited viral replication in a dose-dependent manner. Interestingly, 4 of them, except for auranofin, significantly suppressed human norovirus (HuNoV) replication in human intestinal organoids. In brief, we identified several FDA-approved drugs that inhibit SARS-CoV-2 and HuNoV replication, which warrant further investigation.

The farnesoid X receptor (FXR), a nuclear receptor activated by endogenous bile acids, regulates not only bile acid synthesis but also lipid and carbohydrate metabolism. Therefore, FXR ligands, including FXR antagonists, show potential as therapeutic agents for various metabolic diseases. However, the mechanism by which FXR antagonists influence FXR activity is unclear. We previously synthesized an FXR antagonist, FLG249, which reduced the expression of several FXR target genes in the mouse ileum when orally administered and improved lipid metabolism in the liver and ileum of high-fat diet-induced obese mice. In the present study, we aimed to characterize the mechanism by which FLG249 inhibits the interaction of FXR with its coactivators and corepressors. The LanthaScreen^TM time-resolved fluorescence energy transfer assay and two-hybrid assay were used to evaluate the effect of FLG249 on FXR. We found that, upon binding, FLG249 reduced the interaction of FXR with both coactivators and corepressors. This result suggests that the mechanism of FLG249 as a nuclear receptor modulator is distinct from that of previously reported neutral antagonists and inverse agonists of nuclear receptors.

Mesenchymal stem cell (MSC) sheet therapies are effective in treating intractable diseases. Aligned and oriented bone-marrow-derived MSC sheets have been developed using stripe-patterned thermoresponsive cell culture dishes to increase the effectiveness of MSC therapies compared with unaligned MSC sheets. However, adipose-tissue- and umbilical-cord-derived MSCs (ADMSCs and UCMSCs, respectively) have not yet been used for preparing aligned cell sheets. Therefore, we prepared aligned cell sheets comprising ADMSCs and UCMSCs. We produced a patterned cell culture dish by modifying polyacrylamide into a striped pattern on a commercially available poly(N-isopropylacrylamide)-modified dish. Aligned cell sheets comprising ADMSCs and UCMSCs were successfully prepared in these culture dishes.

The dose-limiting nephrotoxicity of cisplatin (CDDP) is attributed to its accumulation in renal epithelial cells, mediated by uptake via human organic cation transporter 2 (hOCT2) and efflux via human multidrug and toxin extrusion 1 (hMATE1), followed by apoptosis induction via p38 phosphorylation. Recently, we demonstrated that the incidence of CDDP-induced nephrotoxicity was significantly lower in patients receiving palonosetron, a 5-hydroxytryptamine 3 receptor antagonist (5-HT₃RA), than in those receiving other 5-HT₃RAs (ondansetron, ramosetron, and granisetron). However, the underlying mechanism through which palonosetron induces a renoprotective effect remains unclear. In this study, we investigated the effects of 5-HT₃RAs (palonosetron, ondansetron, ramosetron, and granisetron) on hOCT2- and hMATE1-mediated transport of CDDP, as well as on CDDP-induced cytotoxicity. In the CDDP uptake study, none of these 5-HT₃RAs inhibited hOCT2-mediated transport of CDDP at concentrations of 0.1 and 1 μM, except for 10 μM (above clinical concentration). However, ondansetron and ramosetron, unlike palonosetron or granisetron, potently inhibited the hMATE1-mediated transport of CDDP at concentrations of 0.1 and 1 μM. In human embryonic kidney (HEK293) and porcine kidney (LLC-PK₁) epithelial cells, all the tested 5-HT₃RAs (1 μM), except granisetron, reduced CDDP-induced cytotoxicity. Moreover, co-incubation with palonosetron, ondansetron, and ramosetron suppressed CDDP-induced p38 phosphorylation in HEK293 cells. Thus, these findings suggest that concomitant treatment with palonosetron reduces CDDP-induced cytotoxicity by inhibiting p38 phosphorylation, but does not inhibit the hOCT2-mediated transport of CDDP. The present findings provide novel insights into the reduction of CDDP-induced cytotoxicity through concomitant palonosetron treatment.