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Goto, T.

Publications and source records attributed to Goto, T..

17 recordsLinked to original sources

A single-nucleus and spatial transcriptomic atlas of the Syrian hamster preoptic area across hibernation states

Hibernation is an extreme physiological state in certain mammals that is characterized by a reversible reduction in metabolic and thermogenic demands. Although the preoptic area has been implicated in the regulation of hibernation, comprehensive molecular and spatial resources for this brain region in hibernating mammals remain limited. Here, we present an integrated transcriptomic resource of the preoptic area generated using single-nucleus RNA sequencing (snRNA-seq) and Xenium-based spatial transcriptomics in a mammalian hibernator, Syrian hamster. The resource includes cross-species transcriptomic annotations relative to mouse preoptic area datasets, seasonal snRNA-seq datasets obtained under non-hibernating and hibernating conditions, and spatially resolved cell-type annotations generated from Xenium profiling. Together, these datasets provide a reference framework for identifying neuronal populations, examining molecular conservation across species and conditions, and integrating transcriptomic identity with spatial organization.

neuroscience↗

Hypothermic Conditions Impair GnRH Pulse Generator Activity and Gametogenesis

Mammalian reproductive function is driven by arcuate kisspeptin neurons, pacemakers of gonadotropin secretion. During energy shortages, animals reallocate resources from reproduction to survival; however, the underlying neural mechanisms remain elusive. Here we used fiber photometry to chronically monitor synchronized episodes of arcuate kisspeptin neuron activity (SEskiss) in adult mice under various energy-saving conditions. In both sexes, SEskiss frequency was markedly suppressed during fasting-induced torpor and pharmacologically induced hypothermia, whereas hypometabolism alone had no discernible effect. A Q neuron-induced hypothermic state (QIH) robustly suppressed SEskiss, leading to impaired gamete maturation, whereas warming the body temperature during QIH fully restored SEskiss frequency. These findings demonstrate that hypothermia, rather than hypometabolism, is the primary driver of suppression of the hypothalamic reproductive axis during energy-saving conditions. This study provides insights into how thermal signals act as critical gatekeepers in the mammalian reproductive system.

neuroscience↗

Sulfoquinovosylacylpropanediol monotherapy suppresses canine hemangiosarcoma patient-derived xenograft models with vascular remodeling

Canine hemangiosarcoma (HSA) is an aggressive endothelial malignancy with limited therapeutic options, and its progression is closely associated with vascular architecture, stromal remodeling, and inflammatory cell recruitment. Sulfoquinovosylacylpropanediol (SQAP) is a sulfoquinovosyl lipid radiosensitizer reported to affect angiogenic and tumor-microenvironmental pathways, but its effects in canine HSA are unknown. Here, we evaluated SQAP in canine HSA cell lines and patient-derived xenograft (PDX) models. SQAP showed minimal direct cytotoxicity against HSA cell lines in vitro, whereas it significantly suppressed tumor growth in three canine HSA PDX models. Transcriptome analysis of SQAP-treated HSA PDX tumors detected more SQAP-responsive genes in mouse host-derived cells than in canine tumor cells. Gene-set enrichment analysis of the mouse host-derived fraction showed positive enrichment of angiogenesis, hypoxia, and stromal remodeling-related gene sets after SQAP treatment. Subsequent tissue analysis showed that SQAP reduced host-derived CD31-positive vascular area and increased -smooth muscle actin coverage of remaining vessels in two of the three PDX models, while altering macrophage-associated marker profiles in a model-dependent manner. These findings indicate that SQAP suppresses canine HSA PDX growth primarily through vascular and macrophage-associated remodeling of the tumor microenvironment rather than direct tumor-cell cytotoxicity.

cancer biology↗

Lactate dehydrogenase is associated with cholesterol/lipid metabolism, and fluvastatin plus dipyridamole suppresses canine hemangiosarcoma growth in patient-derived xenograft models

Tumor cells commonly exhibit aerobic glycolysis and produce lactate despite oxygen availability. Lactate dehydrogenase (LDH) catalyzes pyruvate-lactate interconversion and regulates intracellular lactate levels. Endothelial cells also depend on glycolysis for ATP production, which prompted us to investigate LDH in canine hemangiosarcoma (HSA), a malignant endothelial tumor. We inhibited LDH with (R)-GNE-140 or sodium oxamate in two canine HSA cell lines (HU-HSA-2 and HU-HSA-3) and generated HU-HSA-3 clones with knockout of LDHA or LDHB to evaluate the effects of LDH perturbation. (R)-GNE-140 and sodium oxamate suppressed proliferation and reduced global histone lactylation levels in both cell lines. mRNA-sequencing (mRNA-seq) of (R)-GNE-140-treated HU-HSA-2 cells identified cholesterol/lipid metabolism-related gene sets among the top negatively enriched pathways. Representative cholesterol/lipid metabolism genes responded differently depending on cell lines and inhibitors. (R)-GNE-140 decreased these genes in HU-HSA-2 but not HU-HSA-3, whereas sodium oxamate decreased them in HU-HSA-3 with limited effects in HU-HSA-2. In HU-HSA-3, LDHA and LDHB knockout clones decreased SREBP2 expression and reduced the number of lipid droplets. Fluvastatin, a cholesterol metabolism inhibitor, inhibited HSA cell growth in vitro but did not significantly suppress tumor growth in two HSA patient-derived xenograft (PDX) models. In contrast, combined fluvastatin and dipyridamole treatment inhibited proliferation in vitro and tumor growth in PDX models. Collectively, these results suggest a context-dependent association between LDH and cholesterol/lipid metabolism in canine HSA cell lines and provide a rationale for further evaluation of combined cholesterol pathway inhibition.

cancer biology↗

Cyclophilin A-mediated cis/trans isomerization modulates RIN4 to control intracellular rhizobial infection in legumes

In most legume-rhizobium symbioses, rhizobial colonization occurs through host-derived intracellular infection threads, which enable recruitment of compatible rhizobia while presumably modulating the host immune system to prevent rejection. To investigate how legumes regulate immune responses through post-translational mechanisms during the infection, we focused on Cyclophilin A (CyPA), a peptidyl-prolyl cis/trans isomerase. The model legume Lotus japonicus encodes three canonical CyPA genes. Among them, LjCyPA1 was characterized through CRISPR/Cas9-mediated knockout analysis and shown to be important for normal intracellular infection of compatible rhizobia. A gain-of-function LjCyPA1 variant in a soybean cultivar was able to promote symbiosis with not only compatible but also incompatible rhizobia. Structural modeling followed by genetic analysis demonstrated a functional interaction between LjCyPA1 and the immune hub protein LjRIN4. The cis conformation of LjRIN4 promoted intracellular rhizobial infection, while the trans conformation suppressed it. LjCyPA1 acted with the rhizobial type III secretion system (T3SS) which exhibited a cooperative role between host and symbiont in facilitating infection. Phylogenomic analysis showed that conservation of the CyPA1 orthologue is correlated with the trait of intracellular infection in legumes. Our results contribute to the understanding of how legumes accept symbiotic partners while balancing immune responses.

plant biology↗

Methionine oxidation of TRPV2 regulates thermogenesis in brown adipocytes

Transient receptor potential vanilloid 2 (TRPV2) is a non-selective cation channel activated by mechanical stimuli and temperatures above 52{degrees}C. Although we have previously reported that TRPV2 regulates non-shivering thermogenesis through facilitating the expression of genes related to thermogenesis, how TRPV2 activity is regulated in brown adipocytes under physiological conditions remains unclear. Recently, it was reported that methionine oxidation was shown to reduce the temperature threshold of TRPV2 for activation to core body temperature or lower. In the present study, we investigated whether methionine oxidation activates TRPV2 and regulates thermogenesis in the differentiated brown adipocytes. As a result, treatment with Chloramine-T (ChT, a methionine oxidant) activated TRPV2 at temperatures of >30{degrees}C in mouseTRPV2-expressing HEK293T cells and in the differentiated brown adipocytes. Moreover, ChT treatment enhanced the expression of genes related to thermogenesis in the differentiated brown adipocytes. These results suggest that methionine oxidation might activate TRPV2 at around body temperature and increase thermogenesis-related gene expression.

physiology↗

Isotope analysis of bird eye lens provides early-life information

Early-life environment has a long-lasting effect on later life, though its estimation is often prevented in the wild because of a lack of available methods. Recently, isotope analysis of eye lenses has attracted considerable interest as a means to reconstruct the environmental conditions experienced by animals during the developmental period. This analysis has mostly been confined to fish for practical reasons and remains to be resolved for application to other animals. In this study, we broadened its applicability by developing a novel approach and verifying its usability for the reconstruction of early-life environments. We performed a feeding experiment using Japanese quail (Coturnix japonica), in which we administered two diets: one composed mainly of C3 plants (low{delta} 13C and high{delta} 15N) and the other of C4 plants (high{delta} 13C and low{delta} 15N). Quails in the control group were continuously fed a C3-based diet from hatching until 200 days old, whereas those in the treatment groups (T10, T15, T20, and T40) were switched from the C3 to the C4-based diet at 10, 15, 20, and 40 days after hatching, respectively. We found that the{delta} 13C in the eye lenses of the treatment groups decreased from the center layer to the middle layer of the lens and then increased toward the outer layer, thus reflecting the diet change. In contrast, those of the control group exhibited a decreasing trend and equilibrated at the middle layer of the eye lens, with no increase thereafter. This novel approach revealed the postnatal feeding histories of the diet-shift experiment. The high{delta} 13C values observed in the center of the eye lenses would reflect the prenatal feeding environment, i.e., the C4-based diet consumed by their mothers, which is further reinforced by higher{delta} 15N values at this position due to the consumption of egg yolk-derived nutrition. These results indicate that the avian eye lens can be used as an "isotopic chronicle," which is a useful tool for reconstructing chronological isotopic information about their early-life history.

ecology↗

Selective Vulnerability of Parvocellular Oxytocin Neurons in Social Dysfunction

Selective vulnerability offers a conceptual framework for understanding neurodegenerative disorders, such as Parkinsons disease, where specific neuronal types are selectively affected while adjacent ones are spared. The applicability of this framework to neurodevelopmental disorders remains uncertain, particularly those characterized by atypical social behaviors such as autism spectrum disorder. Here, employing a single-cell transcriptome analysis in mice, we show that an embryonic disturbance known to induce social dysfunction preferentially impairs gene expressions crucial for neural functions in parvocellular oxytocin (OT) neurons--a subtype linked to social rewards--while neighboring cell types experience a lesser impact. Chemogenetic stimulation of OT neurons at the neonatal stage ameliorated social deficits in early adulthood, concurrent with a cell-type-specific sustained recovery of the pivotal gene expressions within parvocellular OT neurons. Collectively, our data shed light on the transcriptomic selective vulnerability within the hypothalamic social behavioral center and provide a potential therapeutic target through specific neonatal neurostimulation.

neuroscience↗

Orientation-Independent-DIC imaging reveals that a transient rise in macromolecular crowding contributes to mitotic chromosome condensation

Genomic information must be faithfully transmitted into two daughter cells during mitosis. To ensure the transmission process, interphase chromatin is further condensed into mitotic chromosomes. Although protein factors like condensins and topoisomerase II are involved in the assembly of mitotic chromosomes, the physical bases of the condensation process remain unclear. Depletion force/macromolecular crowding, an effective attractive force that arises between large structures in crowded environments around chromosomes, may contribute to the condensation process. To approach this issue, we investigated the "chromosome milieu" during mitosis of living human cells using orientation-independent-differential interference contrast (OI-DIC) module combined with a confocal laser scanning microscope, which is capable of precisely mapping optical path differences and estimating molecular densities. We found that the molecular density surrounding chromosomes increased with the progression from prometaphase to anaphase, concurring with chromosome condensation. However, the molecular density went down in telophase, when chromosome decondensation began. Changes in the molecular density around chromosomes by hypotonic or hypertonic treatment consistently altered the condensation levels of chromosomes. In vitro, native chromatin was converted into liquid droplets of chromatin in the presence of cations and a macromolecular crowder. Additional crowder made the chromatin droplets stiffer and more solid-like, with further condensation. These results suggest that a transient rise in depletion force, likely triggered by the relocation of macromolecules (proteins, RNAs and others) via nuclear envelope breakdown and also by a subsequent decrease in cell-volumes, contributes to mitotic chromosome condensation, shedding light on a new aspect of the condensation mechanism in living human cells. Significance StatementMitotic chromosome condensation is an essential process to transmit replicated chromosomes into two daughter cells during cell division. To study the underlying physical principles of this process, we focused on depletion force/macromolecular crowding, which is a force that attracts large structures in crowded cell environments. Using newly developed special light microscopy, which can image the molecular density of cellular environments, we found that crowding around chromosomes increases during cell division. In vitro, higher concentrations of macromolecules condense chromatin and make it stiffer and more solid-like. Our results suggest that the rise in depletion force renders chromosomes more rigid, ensuring accurate chromosome transmission during cell division.

cell biology↗

Dietary Availability Acutely Governs Puberty Onset via Hypothalamic Neural Circuit

Reproduction poses a substantial burden, especially for mammalian females. Puberty onset serves as a vital checkpoint, regulated based on the bodys energy state, to prevent inappropriate reproductive activity under malnutrition. However, the neural basis of this puberty checkpoint remains poorly understood. Here, we demonstrate that peripubertal malnutrition in female mice reduces the synchronous activity episodes of arcuate kisspeptin neurons (SEskiss), which are critical regulators of the gonadotropin axis. Improved dietary availability boosts SEskiss frequency, facilitating puberty onset. Using a viral-genetic approach, we show that the activating agouti-related protein neurons in the arcuate nucleus (ARCAgrp neurons), a hunger center, suppresses SEskiss, even with enough food. Conversely, loss-of-function of ARCAgrp neurons enhances SEskiss during malnutrition, partly promoting irregular sexual maturation. Collectively, a neural circuit connecting feeding to reproductive centers is responsible for disinhibiting SEskiss frequency based on dietary availability, which sheds light on the neural basis of puberty checkpoint. HighlightsO_LIThe pulsatile activity of arcuate kisspeptin neurons emerges and grows before vaginal opening. C_LIO_LIPubertal impairment resulting from malnutrition is associated with a reduction in the pulsatile activity of kisspeptin neurons. C_LIO_LIPubertal recovery by food availability follows the elevated pulsatile activity of kisspeptin neurons during catch-up growth. C_LIO_LIThe arcuate Agrp neurons suppress the frequency of pulsatile activity of kisspeptin neurons under negative energy balance. C_LI

neuroscience↗

PlantServation: time-series phenotyping using machine learning revealed seasonal pigment fluctuation in diploid and polyploid Arabidopsis

Long-term field monitoring of leaf pigment content is informative for understanding plant responses to environments distinct from regulated chambers, but is impractical by conventional destructive measurements. We developed PlantServation, a method incorporating robust image-acquisition hardware and deep learning-based software to analyze field images, where the plant shape, color, and background vary over months. We estimated the anthocyanin contents of small individuals of four Arabidopsis species using color information and verified the results experimentally. We obtained >4 million plant images over three field seasons to study anthocyanin fluctuations. We found significant effects of past radiation, coldness, and precipitation on the anthocyanin content in the field. The synthetic allopolyploid A. kamchatica recapitulated the fluctuations of natural polyploids by integrating diploid responses. The data support a long-standing hypothesis stating that allopolyploids can inherit and combine the traits of progenitors. PlantServation pipeline facilitates the study of plant responses to complex environments termed "in natura."

plant biology↗

Dynamics of Pulsatile Activities of Arcuate Kisspeptin Neurons in Aging Female Mice

Reproductive senescence is broadly observed across mammalian females, including humans, eventually leading to a loss of fertility. The pulsatile secretion of gonadotropin-releasing hormone (GnRH), which is essential for gonad function, is primarily controlled by kisspeptin neurons in the hypothalamic arcuate nucleus (ARCkiss), the pulse generator of GnRH. The pulsatility of GnRH release, as assessed by the amount of circulating gonadotropin, is markedly reduced in aged animals, suggesting that the malfunctions of ARCkiss may be responsible for reproductive aging and menopause-related disorders. However, the activity dynamics of ARCkiss during the natural transition to reproductive senescence remain unclear. Herein, we introduce chronic in vivo Ca2+ imaging of ARCkiss in female mice by fiber photometry to monitor the synchronous episodes of ARCkiss (SEskiss), a known hallmark of GnRH pulse generator activity, from the fully reproductive to acyclic phase over 1 year. During the reproductive phase, we find that not only the frequency, but also the intensities and waveforms of individual SEskiss, vary depending on the stage of the estrus cycle. During the transition to reproductive senescence, the integrity of SEskiss patterns, including the frequency and waveforms, remains mostly unchanged, whereas the intensities tend to decline. These data illuminate the temporal dynamics of ARCkiss activities in aging female mice. More generally, our findings demonstrate the utility of fiber-photometry-based chronic imaging of neuroendocrine regulators in the brain to characterize aging-associated malfunction. Significance StatementThe transition to reproductive senescence significantly impacts the quality of life of women, but the underlying neural mechanisms remain poorly characterized. Goto and Miyamichi establish long-term (from the reproductive to acyclic phase) chronic imaging of the central pacemaker activities of reproductive functions by fiber photometry in female mice. In particular, they focus on kisspeptin neurons in the arcuate nucleus of the hypothalamus. Their data reveal that during the transition to reproductive senescence, the pulsatile activities of kisspeptin neurons show unexpected robustness in terms of frequency, but a tendency for the intensity to decline. Their findings exhibit the power of direct chronic visualization of hormonal regulators in the brain, which is generally applicable to facilitate studies of aging-associated malfunctions in neuroendocrine systems.

neuroscience↗

Biased re-orientation in the chemotaxis of peritrichous bacteria

Many kinds of peritrichous bacteria that repeat runs and tumbles by using multiple flagella exhibit chemotaxis by sensing a difference in the concentration of the attractant or repellent between two adjacent time points. If a cell senses that the concentration of an attractant has increased, their flagellar motors decrease the switching frequency from counterclockwise to clockwise direction of rotation, which causes a longer run in swimming up the concentration gradient than swimming down. We investigated the turn angle in tumbles of peritrichous bacteria swimming across the concentration gradient of a chemoattractant because the change in the switching frequency in the rotational direction may affect the way tumbles. We tracked several hundreds of runs and tumbles of single Salmonella typhimurium cells in the concentration gradient of L-serine, and found that the turn angle depends on the concentration gradient that the cell senses just before the tumble. The turn angle is biased toward a smaller value when the cells swim up the concentration gradient, whereas the distribution of the angle is almost uniform (random direction) when the cells swim down the gradient. The effect of the observed bias in the turn angle on the degree of chemotaxis was investigated by random walk simulation. In the concentration field where attractants diffuse concentrically from the point source, we found that this angular distribution clearly affects the reduction of the mean square displacement of the cell that has started at the attractant source, that is, the bias in the turn angle distribution contributes to chemotaxis in peritrichous bacteria. Statement of SignificanceWe found another aspect in the chemotactic behavior of peritrichous bacteria. Chemotactic behaviors in peritrichous bacteria were predicted to be observed at the turn angles during tumbles motion as well as at the duration of runs; smaller changes in the swimming direction of cells swimming up the attractants gradient can be observed. This behavior is appropriate because the nature of bacterial chemotaxis changes the switching rate of the rotational direction of the flagellar motors according to the environment. Cells swimming upward reduce the turn angle by switching fewer flagellar motors to loosen flagellar filaments from the bundle during tumbles. We have shown that this prediction is correct.

biophysics↗

Targeting Vitamin-D receptor (VDR) by a small molecule antagonist MeTC7 inhibits PD-L1 but controls THMYCN neuroblastoma growth PD-L1 independently

Vitamin-D receptor (VDR) mRNA is enriched in malignant lung, ovarian and pancreatic tissues and showed poor prognoses. Calcitriol and stable or CRISPR-directed VDR upregulation increased PD-L1mRNA and protein expression in cancer cells in-vitro. A ChIP assay showed the binding of VDR with VDREPD-L1. Stattic, a STAT3 phosphorylation inhibitor blocked calcitriol or VDR overexpression induced PD-L1 upregulation. MeTC7, a VDR antagonist developed by us, reduced PD-L1 expression on macrophages, ovarian, lung, breast, and pancreatic cancer cells in-vitro. In radiotherapy inducible PD-L1 model of orthotopic MC38 murine colon cancer, MeTC7 decreased PD-L1 surface expression, suppressed inflammatory monocytes (IMs) population and increased intra-tumoral CD69+PD1+CD8+T-cells. Intriguingly, MeTC7 reduced TH-MYCN transgenic neuroblastoma tumor growth without affecting PD-L1 and tumor immune milieu. In summary, Vitamin-D/VDR drives PD-L1 expression on cancer cells via STAT-3. Inhibiting VDR exhibited anti-checkpoint effects in orthotopic colon tumors, whereas PDL1-independent and anti-VDR/MYCN effects controlled growth of transgenic neuroblastoma and xenografted tumors. SummaryVitamin-D/VDR induces PD-L1 expression on cancer cells via STAT-3; and targeting VDR by a novel small molecule antagonist MeTC7 exhibits both anti-PD-L1 and anti-VDR/MYCN effects in tumor models.

cancer biology↗

Expression of ACE2 and TMPRSS2 proteins in the upper and lower aerodigestive tracts of rats

Objective Patients with coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), exhibit not only respiratory symptoms but also symptoms of chemo-sensitive disorders and kidney failure. Cellular entry of SARS-CoV-2 depends on the binding of its spike protein to a cellular receptor named angiotensin-converting enzyme 2 (ACE2), and the subsequent spike protein-priming by host cell proteases, including transmembrane protease serine 2 (TMPRSS2). Thus, high expression of ACE2 and TMPRSS2 are considered to enhance the invading capacity of SARS-CoV-2.Methods To elucidate the underlying histological mechanisms of the aerodigestive disorders caused by SARS-CoV-2, we investigated the expression of ACE2 and TMPRSS2 proteins in the aerodigestive tracts of the tongue, hard palate with partial nasal tissue, larynx with hypopharynx, trachea, esophagus, lung, and kidney of rats through immunohistochemistry.Results Strong co-expression of ACE2 and TMPRSS2 proteins was observed in the nasal respiratory epithelium, trachea, bronchioles, alveoli, kidney, and taste buds of the tongue. Remarkably, TMPRSS2 expression was much stronger in the peripheral alveoli than in the central alveoli. These results coincide with the reported clinical symptoms of COVID-19, such as the loss of taste, loss of olfaction, respiratory dysfunction, and acute nephropathy.Conclusions A wide range of organs have been speculated to be affected by SARS-CoV-2 depending on the expression levels of ACE2 and TMPRSS2. Differential distribution of TMPRSS2 in the lung indicated the COVID-19 symptoms to possibly be exacerbated by TMPRSS2 expression. This study might provide potential clues for further investigation of the pathogenesis of COVID-19.Level of Evidence NACompeting Interest StatementThe authors have declared no competing interest.View Full Text

pathology↗

Metabolomic analyses of plasma and liver of mice fed with immature Citrus tumida peel

Supplementing food with functional small molecules has been shown to prevent diseases and improve the quality of life, especially in elderly people. Citrus fruits and citrus fruit-products are popular food supplements across the world. In this study, we focused on a Japanese citrus fruit, Citrus tumida hort. ex Tanaka (C. tumida), and elucidated the effects of supplementation of the peels of immature C. tumida (PIC) on food intake, body and fat tissue weights, and metabolic profiles of plasma and liver in mice. Supplementation with 5% (w/w) PIC for 4 weeks significantly suppressed body weight gain and decreased adipose tissue weight, including that of the epididymal, perirenal, and subcutaneous fats. Metabolome analyses using capillary electrophoresis time-of-flight mass spectrometry showed that the level of 2-hydroxyvaleric acid was reduced in the blood plasma of mice fed with PIC. Supplementation with PIC significantly elevated the levels of dipeptides (Thr-Asp, Ser-Glu, and Ala-Ala), glucuronic acid (and/or galacturonic acid-2), and S-methylglutathione, and significantly reduced the levels of betaine aldehyde in the liver. In conclusion, PIC supplementation affects the metabolism of fatty acids, pectin, glutathione, and choline. Our study demonstrates the potential beneficial effects of PIC, especially in metabolic syndrome and obesity. PIC may be developed as a functional food and used in the treatment of these diseases. Nutritional and metabolome studies are effective in studying the effects of specific dietary supplements and will contribute to the development of functional foods.

biochemistry↗

The administration of high-mobility group box 1 fragment prevents deterioration of cardiac performance by enhancement of bone marrow mesenchymal stem cell homing in the delta-sarcoglycan-deficient hamster

ObjectivesWe hypothesized that systemic administration of high-mobility group box 1 fragment attenuates the progression of myocardial fibrosis and cardiac dysfunction in a hamster model of dilated cardiomyopathy by recruiting bone marrow mesenchymal stem cells thus causing enhancement of a self-regeneration system.\n\nMethodsTwenty-week-old J2N-k hamsters, which are {delta}-sarcoglycan-deficient, were treated with systemic injection of high-mobility group box 1 fragment (HMGB1, n=15) or phosphate buffered saline (control, n=11). Echocardiography for left ventricular function, cardiac histology, and molecular biology were analyzed. The life-prolonging effect was assessed separately using the HMGB1 and control groups, in addition to a monthly HMGB1 group which received monthly systemic injections of high-mobility group box 1 fragment, 3 times (HMGB1, n=11, control, n=9, monthly HMGB1, n=9).\n\nResultsThe HMGB1 group showed improved left ventricular ejection fraction, reduced myocardial fibrosis, and increased capillary density. The number of platelet-derived growth factor receptor-alpha and CD106 positive mesenchymal stem cells detected in the myocardium was significantly increased, and intra-myocardial expression of tumor necrosis factor stimulating gene 6, hepatic growth factor, and vascular endothelial growth factor were significantly upregulated after high-mobility group box 1 fragment administration. Improved survival was observed in the monthly HMGB1 group compared with the control group.\n\nConclusionsSystemic high-mobility group box 1 fragment administration attenuates the progression of left ventricular remodeling in a hamster model of dilated cardiomyopathy by enhanced homing of bone marrow mesenchymal stem cells into damaged myocardium, suggesting that high-mobility group box 1 fragment could be a new treatment for dilated cardiomyopathy.

molecular biology↗