Biology subjects

Higuchi, S.

Publications and source records attributed to Higuchi, S..

11 recordsLinked to original sources

bioRxiv2026

Polygenic evolution towards a morning chronotype in modern humans

Chronotype is a behavioural phenotype, and its phenotypic trend is considered to change at higher latitudes. In the current study, we performed a polygenic assessment of chronotype trend using associated single nucleotide polymorphisms identified by a genome wide-association study. We found that the phenotypic trend towards morningness increased drastically during the migration of anatomically modern humans above 20 degrees north. Furthermore, two types of latitudinal selection of morningness alleles contributed to establishing the trend towards the morning chronotype at higher latitudes. We propose that the trend towards morningness is stronger in present-day modern humans living above 20 degrees north than in Neanderthals.

evolutionary biology↗

bioRxiv2026

Manganese availability determines insulin sensitivity by enhancing Akt activity

Insulin signaling is a critical determinant of metabolic health, and impairments in insulin action contribute to the development of type 2 diabetes. The kinase Akt is a central mediator of insulin signaling and is required for insulin's suppression of hepatic glucose output. Although the regulation of Akt by the insulin receptor-PI3K pathway is well understood, there are instances in which signaling downstream of Akt is dissociated from proximal insulin signaling, for example in insulin resistance. Nonetheless, little is known about PI3K-independent mechanisms of Akt regulation. Here, we discovered that hepatocyte manganese concentrations are a key determinant of PI3K-independent Akt function in vivo. We further demonstrated that manganese increases Akt's catalytic efficiency, and quantitative phosphoproteomics revealed that manganese and insulin act additively to enhance Akt activity. Moreover, we uncovered that hepatic manganese concentrations fluctuate during fasting and feeding via carbohydrate-dependent transcriptional regulation of the manganese efflux transporter Slc30a10. This dynamic metal-signaling axis provides a mechanistic link between nutrient status and Akt activation, and suggests a molecular explanation for the glucose-lowering effects of manganese observed in humans. Our findings establish manganese as a physiologically regulated cofactor for Akt and position metal bioavailability as a previously unrecognized layer of insulin signaling control.

physiology↗

bioRxiv2026

Divergent mechanics of inner ear morphogenesis are coupled to developmental tempo over vertebrate evolution

Vertebrate embryos vary in size and developmental tempo based on reproductive strategies; however, organs of ancient origin, such as the eye and inner ear, remain highly conserved in structure and function. How both diverse embryonic traits and conserved organ development occur remains unclear. Here, we identify divergent morphogenetic mechanics of inner ear development, particularly in vesicular primordium expansion, in 12 species representing the major vertebrate lineages. Differences in cell volume regulation determine tissue growth mechanics, which diversify the expansion process but yield a conserved morphological outcome. Heterochronic shifts in organogenesis allow this regulation to evolve in coordination with a prolonged developmental period. These findings suggest that alternative morphogenetic mechanics mitigate the effects of diversified embryonic traits, thereby ensuring consistent morphological outcomes for highly conserved organs.

evolutionary biology↗

bioRxiv2025

Functional impact of pathogenic Runt domain mutations in Runx2 in vivo: Insights into the skeletal and dental anomalies of cleidocranial dysplasia

Runt-related transcription factor 2 (RUNX2) is essential for skeletogenesis, and mutations in its gene cause cleidocranial dysplasia (CCD), an autosomal dominant skeletal disorder. The evolutionarily conserved 128-amino acid Runt homology domain (RHD) of human RUNX2 is essential for DNA binding and heterodimerization, and serves as a mutation hotspot associated with severe CCD phenotypes. To elucidate the functional impact of pathogenic RHD mutations in vivo, we generated two novel mouse lines: one carrying a missense mutation, c.695G>A (p.R232Q) (Runx2m/+), corresponding to the human RUNX2 c.674G>A (p.R225Q), and the other harboring a frameshift mutation, c.697_698delGA (p.E233TfsTer9) (Runx2112/+), causing a premature stop codon. Homozygous Runx2m/mand Runx2112/112 mice lacked membranous ossification, whereas heterozygous Runx2m/+ and Runx2112/+ mice displayed typical CCD-like skeletal features, including an open anterior fontanelle and clavicle hypoplasia. Unexpectedly, heterozygotes carrying pathogenic mutations in RHD developed an accessory root-like protrusion at the furcation of three-rooted maxillary first molars, representing a previously unrecognized dental phenotype during root development. Dual luciferase assays revealed impaired transactivation of the p.R232Q mutant Runx2 on the osteocalcin enhancer/promoter. Wild-type Runx2 was robustly expressed in osteoblasts and hypertrophic chondrocytes during bone formation, but the mutant Runx2 exhibited reduced expression in hypertrophic chondrocytes and partially impaired nuclear localization, resulting in arrested osteoblast and chondrocyte maturation. Our mutant mouse model provides a valuable in vivo platform to study CCD pathogenesis, mechanisms of tooth root furcation, and therapeutic interventions targeting dysfunctional RHD.

genetics↗

bioRxiv2023

Sclerostin modulates the degree of mineralization and the stiffness profile of the fibrocartilaginous enthesis for mechanical tissue integrity

Fibrocartilaginous entheses consist of four graded tissue layers including tendon, the unmineralized and mineralized fibrocartilage, and subchondral bone with varying degrees of stiffness. Here we examined the functional role of sclerostin that is expressed in mature mineralized fibrochondrocytes. Following rapid mineralization of the unmineralized fibrocartilage and parallel replacement of epiphyseal hyaline cartilage by bone, the unmineralized fibrocartilage re-expanded after a decline in alkaline phosphatase activity at the mineralization front. Sclerostin was co-expressed with osteocalcin in the bottom of the mineralized fibrocartilage adjacent to subchondral bone. In Scx deficient mice with less mechanical loading due to defects of the Achilles tendon, the number of sclerostin+ fibrochondrocytes was significantly reduced in the defective enthesis where chondrocyte maturation was markedly impaired in both fibrocartilage and hyaline cartilage. Loss of the Sost gene, coding for sclerostin, caused increased mineral density in the mineralized zones of the fibrocartilaginous enthesis. Atomic force microscopy analysis revealed the higher stiffness of fibrocartilage. These lines of evidence suggest that sclerostin in mature mineralized fibrochondrocytes acts as a modulator for mechanical tissue integrity of the fibrocartilaginous enthesis.

developmental biology↗

bioRxiv2022

The python-derived 16α-hydroxylated bile acid, pythocholic acid decreases food intake and increases jejunal fatty acid ethanolamides in mice.

ObjectiveModulation of bile acid (BA) structure is a potential strategy for obesity and metabolic disease treatment. BAs act not only as signaling molecules involved in energy expenditure and glucose homeostasis, but also as regulators of food intake. The structure of BAs, particularly the position of the hydroxyl groups of BAs impacts food intake partly by intestinal effects: (1) modulating the activity of N-acyl phosphatidylethanolamine phospholipase D (NAPE-PLD), which produces the anorexigenic bioactive lipid oleoylethanolamide (OEA), or (2) regulating lipid absorption and the gastric emptying-satiation pathway. We hypothesized that 16-hydroxylated BAs uniquely regulate food intake, because of the long intermeal intervals in snake species in which these BAs are abundant. However, the effects of 16-hydroxylated BAs in mammals are completely unknown, because 16-hydroxylated BAs are not naturally found in mammals. To test the effect of 16-hydroxylated BAs on food intake, we isolated the 16-hydroxylated BA pythocholic acid from ball pythons (Python regius). MethodsPythocholic acid or deoxycholic acid (DCA) were given by oral gavage in mice. DCA is known to increase NAPE-PLD activity better than other mammalian BAs. We evaluated food intake, OEA levels and gastric emptying in mice. ResultsWe successfully isolated pythocholic acid from ball pythons for experimental use. Pythocholic treatment significantly decreased food intake compared with DCA treatment, and this was associated with increased jejunal OEA, but no change in gastric emptying or lipid absorption. ConclusionThe exogenous bile acid pythocholic acid is a novel regulator of food intake and the satiety signal OEA in the mouse intestine. HighlightsO_LIPythocholic acid decreases food intake. C_LIO_LIPythocholic acid increases intestinal OEA and other fatty acid ethanolamides. C_LIO_LIThe effects of pythocholic acid on OEA and hypophagia are greater than the effects of DCA. C_LIO_LIPythocholic acid does not affect lipid absorption or gastric emptying. C_LI

pathology↗

bioRxiv2022

Improving the Safety of Cultured Meat Using Basal Medium Prepared using Food Ingredients

Currently, meat production involves environmental issues and high costs; one solution to address this may be to produce meat via cell culture. Therefore, there is an urgent demand for the development of cell culture methods that replace raw materials with food materials to produce cultured meat as food. In this study, we designed food-grade-Dulbeccos Modified Eagles Medium (FG-DMEM); when the cells cultured in FG-DMEM and regular DMEM were compared, there was no significant difference in cell growth or differentiation. Therefore, FG-DMEM can be used for research and safe production of cultured meat.

cell biology↗

bioRxiv2021

Absence of muricholic acid due to Cyp2c-deficiency protects against high fat diet-induced obesity in male mice but promotes liver damage

ObjectiveMurine-specific muricholic acids (MCAs) are reported to protect against obesity and associated metabolic disorders. However, the response of mice with genetic depletion of MCA to an obesogenic diet has not been evaluated. We used Cyp2c-deficient (Cyp2c-/-) mice, which lack MCAs and thus have a human-like bile acid (BA) profile, to directly investigate the potential role of MCAs in diet-induced obesity. MethodsMale and female Cyp2c-/- mice and wild-type controls were fed a standard chow diet or a high fat diet (HFD) for 18 weeks. We measured BA composition from a pool of liver, gallbladder, and intestine, as well as weekly body weight, food intake, lean and fat mass, systemic glucose homeostasis, energy expenditure, intestinal lipid absorption, fecal lipid, and energy content. ResultsCyp2c deficiency depleted MCAs and caused other changes in BA composition, namely a decrease in the ratio of 12-hydroxylated (12-OH) BAs to non-12-OH BAs, without altering the total BA levels. While wild-type male mice became obese after HFD-feeding, Cyp2c-/- male mice were protected from obesity and associated metabolic dysfunctions. Cyp2c-/- male mice also showed reduced intestinal lipid absorption and increased lipid excretion, which was reversed by oral gavage with the 12-OH BA, taurocholic acid. Cyp2c-/- mice also showed increased liver damage, which appeared stronger in females. ConclusionMCA does not protect against diet-induced obesity but may protect against liver injury. Reduced lipid absorption in Cyp2c-deficient male mice is potentially due to a reduced ratio of 12-OH/non-12-OH BAs.

physiology↗

bioRxiv2020

Fat Mass Regain in Middle-Aged Mice after Sleeve Gastrectomy is divergent from plasma leptin levels

BackgroundSome degree of weight regain is typically observed in human patients who undergo Sleeve Gastrectomy (SG), even if the majority of them do not return to their presurgical body weight. Although the majority of bariatric surgery patients are middle aged, most preclinical models of bariatric surgery utilize juvenile male mice. A long-term characterization of the response of mature, wild type, obese male mice to SG has not been performed. MethodsEight-month old C57bl/6J obese male mice were randomized to undergo SG, sham surgery without caloric restriction (SH) or sham surgery with caloric restriction to match body weight to the SG group (SWM). Body weight, body composition and glucose tolerance were matched at baseline. Mice were followed for 60 days following their respective surgeries. ResultsSG mice had a more pronounced percent weight loss than the SH group in the first post-operative month (p<0.05), along with fat mass loss (p<0.01). By the second post-operative month, the SG group started to regain fat mass, although it continued to be statistically lower than the SH group (p<0.05). Cumulative food intake was significantly lower in the SG group compared to SH group only in the first post-operative week (p<0.05), with both groups having similar cumulative food intake thereafter (p>0.05). SWM group had a significantly lower cumulative food intake throughout the study, except for week 1 (p<0.01). Glucose tolerance was only demonstrably better in the SG group compared to SH group at 8 weeks post-operatively (p<0.01). Plasma leptin was significantly lower in the SG group compared to both SWM and SH groups group by the second post-operative month (p<0.01), in spite of SGs increasing fat mass accumulation. In the second post-operative month, both FGF-21 and GDF-15 were increased in the SH group compared to the SG and SWM groups (p<0.05), while there was no difference in plasma insulin among the three groups. Heat production was surprisingly higher in the SH group compared to the other two groups (p<0.05), even though brown adipose tissue Peroxisome Proliferator-Activated Receptor Gamma (PPARg) and Cidea mRNA expression were significantly higher in SG and SWM compared to SH (p<0.01). There was no change in BAT UCP-1 mRNA expression among the groups (p>0.05). There was also no change in fecal lipid content among the groups (p>0.05). ConclusionsSG in obese, middle aged male mice leads is accompanied by fat mass regain in the second post-operative month, while plasma leptin levels continue to be significantly lower. This raises the question of whether the observed fat mass regain consists mostly of visceral adipose tissue.

physiology↗

bioRxiv2020

Sleeve gastrectomy promotes sustained weight loss while increasing heat production in middle aged, obese female mice

BackgroundSleeve gastrectomy (SG) is currently the most frequently performed bariatric surgery in the United States. The majority of patients undergoing SG are middle aged women. Most preclinical models of bariatric surgery, however, utilize juvenile male mice. A long-term characterization of the response of mature wild type, obese female mice to SG has not been performed. Thus, we set out to characterize the response of middle aged obese female mice to SG. MethodsTen-month old C57bl/6J obese female mice were randomized to undergo SG, sham surgery without caloric restriction (SH) or sham surgery with caloric restriction to match body weight to the SG group (SWM). Body weight, body composition and glucose tolerance were matched at baseline. Mice were followed for 60 days following their respective surgeries. ResultsThe SG group had a more pronounced percent weight loss than the SH and SWM control groups (p<0.05), while consuming more calories than the SWM group (p<0.05). The SG group had a significant improvement in glucose tolerance compared to the SH control group (p<0.05). Plasma leptin was significantly decreased in the SG and SWM group, compared to the SH group (p<0.01). Unexpectedly, FGF-21 was increased in the SH group compared to the SG and SWM groups (p<0.01), while there was no difference in plasma insulin among the three groups. Heat production was increased in the SG group compared to SWM and SH groups (p<0.001). SG also had a significantly increased mRNA expression of Uncoupling Protein 1 (UCP-1), Adiponectin and Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha (PGC1-alpha) in brown adipose tissue (BAT), compared to SWM and SH groups. Both SG and SWM groups had increased fecal lipid excretion (p<0.05), compared to the SH group. ConclusionsSG in obese, middle aged female mice leads to sustained weight loss and blood glucose improvement. It appears that increased metabolism in BAT may be linked to these effects.

physiology↗

bioRxiv2020

Bile acid composition regulates the manganese transporter Slc30a10 in intestine

Bile acids (BAs) comprise heterogenous amphipathic cholesterol-derived molecules that carry out physicochemical and signaling functions. A major site of BA action is the terminal ileum, where enterocytes actively reuptake BAs and express high levels of BA-sensitive nuclear receptors. BA pool size and composition are affected by changes in metabolic health, and vice versa. One of several factors that differentiate BAs is the presence of a hydroxyl group on C12 of the steroid ring. 12a-hydroxylated BAs (12HBAs) are altered in multiple disease settings, but the consequences of 12HBA abundance are incompletely understood. We employed mouse primary ileum organoids to investigate the transcriptional effects of varying 12HBA abundance in BA pools. We identified Slc30a10 as one of the top genes differentially induced by BA pools with varying 12HBA abundance. SLC30A10 is a manganese (Mn) efflux transporter critical for whole-body manganese excretion. We found that BA pools, especially those low in 12HBAs, induce cellular manganese efflux, and that Slc30a10 induction by BA pools is driven primarily by lithocholic acid signaling via the vitamin D receptor. Administration of lithocholic acid or a vitamin D receptor agonist resulted in increased Slc30a10 expression in mouse ileum epithelia. These data demonstrate a previously unknown role for BAs in intestinal control of Mn homeostasis.

cell biology↗