Biology subjects

Fukushima, S.

Publications and source records attributed to Fukushima, S..

9 recordsLinked to original sources

bioRxiv2026

2-arm-PEG-oligocations transiently shield the liver sinusoids to mitigate off-target hepatic expression of mRNA lipid nanoparticles

Ionizable lipid nanoparticles (iLNPs) are powerful platforms for mRNA-based vaccines and immunotherapies; however, their intrinsic liver tropism compromises both safety and efficacy. Off-target hepatic protein expression from delivered mRNA raises safety concerns, and hepatic clearance limits efficient iLNP delivery to target organs. In this study, we address these challenges in mouse models by stealth-coating the liver sinusoidal endothelial (LSE) wall, the primary gateway for nanoparticle entry into the liver. Specifically, oligocations conjugated with two-armed PEG (2-arm-PEG-oligocations), a clinically relevant material used in oligonucleotide delivery trials, were employed to transiently anchor PEG to the LSE wall with balanced affinity, ensuring robust coating followed by gradual biliary clearance. This approach reduced hepatic protein expression from iLNPs, subsequently administered either systemically or locally, by more than tenfold. Importantly, the strategy preserved iLNP accumulation in the spleen, a key target organ for vaccines, effectively redirecting iLNPs from the liver to the spleen. Consequently, in vaccine applications, pre-injection of the 2-arm-PEG-oligocation preserved or even enhanced vaccination efficacy while minimizing concerns associated with antigen expression in the liver. In applications involving cytokine mRNA therapy, specifically intratumoral interleukin-12 (IL-12) mRNA administration, systemic pre-injection of the 2-arm-PEG-oligocation successfully reduced off-target hepatic IL-12 expression and subsequent systemic IL-12 exposure, while maintaining antitumor efficacy. Collectively, these results demonstrate that LSE-wall stealth coating is a generalizable strategy to improve both the safety and efficacy of iLNP-based mRNA vaccines and immunotherapies.

bioengineering↗

bioRxiv2026

Inflammatory IL-1 signaling remodels epidermal stem cell compartments by suppressing Wnt activity

The skin epidermis is maintained by spatially organized stem cell populations with distinct cellular dynamics; however, how inflammation affects this heterogeneity remains largely unknown. Here, we demonstrate that acute skin inflammation alters epidermal stem cell compartments through IL-1-mediated suppression of canonical Wnt signaling. Lineage tracing in inflamed mouse skin revealed that slow-cycling Dlx1+ epidermal stem cell clones persist, whereas fast-cycling Slc1a3+ clones decline through enhanced differentiation and lineage conversion, driving the reorganization of epidermal stem cell compartments. IL-1 signaling is both necessary and sufficient for this change: administration of IL-1/{beta} recapitulates these effects, while transgenic induction of the IL-1 decoy receptor preserves the balance of stem cell populations. IL-1 suppresses canonical Wnt activity in both the mouse epidermis and human keratinocytes, and Wnt ligand administration restores the fast-cycling compartment in vivo. Together, these results identify a reversible IL-1-Wnt axis that governs inflammation-induced stem cell plasticity and spatial tissue remodeling. HighlightO_LIInflammation induces reversible remodeling of epidermal stem cell compartments C_LIO_LIDistinct epidermal stem cell populations exhibit differential responses to inflammation C_LIO_LIIL-1 suppresses canonical Wnt signaling, thereby biasing fast-cycling stem cell behavior C_LIO_LIReactivation of Wnt signaling restores stem cell population balance under inflammatory conditions C_LI O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=132 SRC="FIGDIR/small/704488v1_ufig1.gif" ALT="Figure 1"> View larger version (50K): org.highwire.dtl.DTLVardef@e430e5org.highwire.dtl.DTLVardef@1464550org.highwire.dtl.DTLVardef@70ba1borg.highwire.dtl.DTLVardef@ca502c_HPS_FORMAT_FIGEXP M_FIG C_FIG

developmental biology↗

bioRxiv2025

Internal desynchrony of the circadian clock system in middle-aged mice under social jet lag-like conditions

Social jet lag (SJL) refers to the discrepancy in sleep patterns between weekdays and weekends, leading to a misalignment between the internal clock and social time. In this study, we investigated the effects of weekly shifts in light-dark (LD) conditions: two days per week with 6-h delayed LD cycles (simulating Saturday and Sunday), followed by a 6-h advance on Monday. Core body temperature rhythms rapidly entrained to the delayed LD cycles on weekends, and these delayed rhythms persisted even after the LD cycle was advanced on Monday. In contrast, plasma corticosterone rhythms on Mondays were aligned with the LD cycle but exhibited reduced amplitude. In the livers of SJL mice on Monday, the expression rhythms of Per1, Per2, and Hsp70 were delayed by 3-5 h compared to that in the controls, whereas Rev-erb expression rhythms remained comparable to those of the controls. The expression of lipid and glucose metabolism-related genes in the liver showed either delayed rhythms or no significant changes. To determine whether the dissociation of gene expression rhythms resulted from gene-specific responses to circadian body temperature and hormonal signals, we conducted ex vivo culture experiments using mouse liver slices. High-temperature stimulation induced Per2 and Hsp70 expression, while dexamethasone induced Per1 expression. High temperature and dexamethasone affected distinct sets of metabolic genes, whereas insulin induced only minor changes. Moreover, these responses were strongly influenced by the age and light exposure of the mice. We also examined the effect of weekly housing by providing environmental enrichment (EE), which had minimal impact on circadian parameters but promoted anti-aging effects on bone density and behavior. Overall, our findings indicate that weekly shifts in LD cycles induce internal desynchronization within the hepatic molecular clock and metabolic pathways by uncoupling core body temperature rhythms, hormonal rhythms, and gene-specific responses to stimuli.

physiology↗

bioRxiv2023

The genetic evolution of acral melanoma

Acral melanoma is an aggressive type of melanoma with unknown origins, arising on the sole, palm, or nail apparatus. It is the most common type of melanoma in individuals with dark skin and is notoriously challenging to treat. Our study examined exome sequencing data from 139 tissue samples, spanning different progression stages, collected from 37 patients. We found that 78.4% of the melanomas displayed one or more clustered copy number transitions with focal amplifications, recurring predominantly on chromosomes 5, 11, 12, and 22. These genomic "hailstorms" were typically shared across all progression stages within individual patients. Genetic alterations known to activate TERT also arose early. By contrast, mutations in the MAP- kinase pathway appeared later during progression, often leading to different tumor areas harboring non-overlapping driver mutations. We conclude that the evolutionary trajectories of acral melanomas substantially diverge from those of melanomas on sun-exposed skin, where MAP-kinase pathway activation initiates the neoplastic cascade followed by immortalization later. The punctuated formation of hailstorms, paired with early TERT activation, suggests a unique mutational mechanism underlying the origins of acral melanoma. Our findings highlight an essential role for telomerase, likely in re-stabilizing tumor genomes after hailstorms have initiated the tumors. The marked genetic heterogeneity, in particular of MAP-kinase pathway drivers, may partly explain the limited success of targeted and other therapies in treating this melanoma subtype.

cancer biology↗

bioRxiv2023

Phylogeographical evidence for historical long-distance dispersal in the flightless stick insect Ramulus mikado

Exploring how organisms overcome geographical barriers to dispersal is a fundamental question in biology. Passive long-distance dispersal events, although infrequent and unpredictable, have a considerable impact on species range expansions. Despite limited active dispersal capabilities, many stick insect species have vast geographical ranges, indicating that passive long-distance dispersal is vital for their distribution. A potential mode of passive dispersal in stick insects is via the egg stage within avian digestive tracts, as suggested by experimental evidence. However, detecting such events under natural conditions is challenging due to their rarity. To indirectly assess the importance of historical avian-mediated dispersal, we examined the population genetic structure of the flightless stick insect Ramulus mikado based on a multifaceted molecular approach (COI haplotypes, nuclear SSR markers, and genome-wide SNPs). Subsequently, we identified unique phylogeographic patterns, including the discovery of identical COI genotypes spanning considerable distances, which substantiates the notion of passive long-distance genotypic dispersal. Overall, all the molecular data revealed low and mostly non-significant genetic differentiation among populations, with identical or very similar genotypes across distant populations. We propose that long-distance dispersal facilitated by birds is the most plausible explanation for the unique phylogeographic pattern observed in this flightless stick insect.

evolutionary biology↗

bioRxiv2023

The role of hnRNP A3 on age-related increased expression of FIX in the Liver

HnRNP A3 is a protein that binds the age-related increase element (AIE) of blood coagulation factor IX (FIX) and that plays critical roles in age-related gene expression, likely through an epigenetic mechanism as yet unidentified. In a previous study, we found that Ser359 phosphorylated hnRNP A3 proteins do not bind to the AIE of FIX although both unphosphorylated and Ser359 phosphorylated hnRNP proteins exist in the liver. In the present study, to explore the relationship between hnRNP A3 and FIX, we examined the age-related expression pattern of 14 single spots of hnRNP A3 detected by 2DE and subsequent MALDI-TOF/TOF/MS analyses in mouse liver. We found that the level of all four Ser359 phosphorylated hnRNP A3 proteins increased with age (from 1-21 months), while the 10 unphosphorylated hnRNP A3 proteins showed various expression patterns with age. We then examined the functional role of hnRNP A3 in FIX expression using siRNA knockdown technology targeting the hnRNP A3 gene in aged mice (12-17 months old). Inhibition of hnRNP A3 expression induced an increase in the circulating FIX level in aged mice. These results suggested that hnRNP A3 inhibits age-related FIX protein expression and that age-dependent modification of hnRNP A3, including its phosphorylation at Ser359, might be involved in the age-dependent increase in FIX expression in vivo.

physiology↗

bioRxiv2022

Tethering designer short double-stranded RNA to mRNA for co-delivery of molecularly-targeted adjuvants and antigens towards cancer vaccination

Integrating antigen-encoding mRNA and immunostimulatory adjuvant into a single formulation is a promising approach to potentiating the efficacy of mRNA vaccines. Here, we developed a scheme based on RNA engineering to integrate adjuvancy directly into antigen-encoding mRNA strands without hampering the ability to express antigen proteins. Short double-stranded RNA (dsRNA) was designed to target retinoic acid-inducible gene-I (RIG-I), an innate immune receptor, for effective cancer vaccination and then tethered onto mRNA strand via hybridization. Tuning the dsRNA structure and microenvironment by changing its length and sequence enabled the determination of the structure of dsRNA-tethered mRNA efficiently stimulating RIG-I. Eventually, the formulation loaded with dsRNA-tethered mRNA of the optimal structure effectively activated mouse and human dendritic cells and drove them to secrete a broad spectrum of proinflammatory cytokines without increasing the secretion of anti-inflammatory cytokines. Notably, the immunostimulating intensity was tunable by modulating the number of dsRNA along mRNA strand, which prevents excessive immunostimulation. Versatility in the applicable formulation is a practical advantage of the dsRNA-tethered mRNA. Its formulation with three existing systems, i.e., anionic lipoplex, ionizable lipid-based lipid nanoparticles, and polyplex micelles, induced appreciable cellular immunity in the mice model. Of particular interest, dsRNA-tethered mRNA encoding ovalbumin (OVA) formulated in anionic lipoplex used in clinical trials exerted a significant therapeutic effect in the mouse lymphoma (E.G7-OVA) model. In conclusion, the system developed here provides a simple and robust platform to supply the desired intensity of immunostimulation in various formulations of mRNA cancer vaccines.

bioengineering↗

bioRxiv2020

Behavioural cue reactivity to alcohol and non-alcohol-related stimuli among individuals with severe alcohol use disorder: an fMRI study with a visual task

Patients with alcohol use disorder (AUD) have difficulties controlling alcohol cravings and thus exhibit increased use and earlier relapse. Although patients tend to respond more strongly to alcohol-related images compared with non-alcohol-related images, few researchers examined the factors that modulate cravings. Here, we examined whole-brain blood oxygen level-dependent (BOLD) responses to behavioural cues in individuals with AUD and healthy controls (HCs). The participants included 24 patients with severe AUD and 15 HCs. We presented four beverage images (juice, drinking juice, sake, and drinking sake) and compared participant BOLD responses between the two groups. Multiple comparisons revealed that the AUD group had lower BOLD responses compared with the HC group to images of drinking juice in the left precuneus (p = 0.036) and the left posterior cingulate cortex (PCC) (p = 0.044) and higher BOLD responses to images of drinking sake in the left PCC (p = 0.044). Furthermore, compared to the HCs, the AUD patients had decreased BOLD responses associated with cue reactivity to drinking juice in the left precuneus during the period from 15 to 18 s (p = 0.004, df = 37) and 18 to 21 s (p = 0.002, df = 37). Using the Spearman correlation, we found a significant negative correlation between BOLD responses in the left PCC of the AUD patients and Mini-Mental State Examination (MMSE) scores (r = -0.619, p = 0.001). Our findings suggest that HCs and severe AUD patients differ in their responses not to images of alcoholic beverages but those related to alcohol drinking behavior. Thus, these patients appear to have different patterns of brain activity. This information may aid clinicians in developing treatments for patients with AUD.

neuroscience↗

bioRxiv2018

Excitable dynamics of Ras triggers self-organized PIP3 signaling for spontaneous cell migration

Spontaneous cell movement is underpinned by an asymmetric distribution of signaling molecules including small G proteins and phosphoinositides on the cell membrane. A fundamental question is the molecular mechanism for the spontaneous symmetry breaking. Here we report that GTP bound Ras (Ras-GTP) breaks the symmetry due to excitability even in the absence of extracellular spatial cues and cytoskeletal polarity as well as downstream signaling activities. A stochastic excitation of local and transient Ras activation induced PIP3 accumulation via direct interaction with PI3K, causing tightly coupled traveling waves propagating along the membrane. Comprehensive phase analysis of the waves of Ras-GTP and PIP3 metabolism-related molecules revealed the network structure of the excitable system including positive feedback regulation of Ras-GTP by PIP3. A mathematical model reconstituted a series of the observed symmetry breaking phenomena, illustrating an essential involvement of excitability in the cellular decision-making process.\n\nAuthor contributionsS.F. conducted the experiments; all authors analyzed the data and wrote the manuscript.

cell biology↗