Biology subjects

Sugiyama, K.

Publications and source records attributed to Sugiyama, K..

5 recordsLinked to original sources

bioRxiv2026

β-Adrenergic inhibition of exocytotic surface deposition of MHCII molecules in reactive astrocytes is mediated by amisyn

Degeneration of the locus coeruleus, a noradrenergic nucleus, reduces noradrenaline bioavailability in the central nervous system and promotes neuroinflammation via reactive astrocytes, although the underlying mechanisms remain unclear. We investigated whether interferon-{gamma}-induced expression of major histocompatibility complex class II (MHCII), a marker of pro-inflammatory reactive astrocytes, is regulated by adrenergic receptors and amisyn. {beta}-Adrenergic, but not -adrenergic, stimulation increased cyclic adenosine monophosphate (cAMP) and reduced MHCII expression, as detected immunocytochemically, in human and rat astrocytes. {beta}-Adrenergic treatment altered transient exocytosis of lysosome-like vesicles, increasing event frequency and reducing fusion-pore conductance and dwell time, thereby limiting MHCII surface expression. Overexpression of wild-type amisyn inhibited surface expression of MHCII and the lysosomal marker CD63 and reduced fusion-pore conductance and dwell time. Conversely, amisyn knockdown enhanced full fusion exocytosis of larger vesicles and abolished {beta}-adrenergic effects, indicating that amisyn mediates {beta}-adrenergic inhibition of exocytosis and MHCII surface deposition.

neuroscience↗

bioRxiv2026

Osteopontin Upregulation Defines a Pre-Rupture State in Thoracic Aortic Aneurysms in Mice and Humans

BackgroundThoracic aortic aneurysm (TAA) is a life-threatening condition with an unpredictable lisk of rupture. Current clinical parameters have limited ability to accurately predict imminent rupture. Osteopontin (OPN) has been implicated in aortic aneurysm pathology, however, it role as a marker of imminent rupture remains. unclear. We investigated the dynamics of OPN expression dynamics in a mouse model with predictable rupture timing and validated our findings in human TAA. MethodsOne-month-old fibrillin-1 hypomorphic (Fbn1mgR/mgR) mice were used as a TAA model; with wild-type (WT) mice served as controls. Angiotensin II (AngII) was administered to Fbn1mgR/mgR to induce acute aortic rupture. Single-section transcriptome analysis and immunofluorescence staining were performed on ascending aortic tissue at 24 and 72 hours after AngII infusion, with pre-treatment Fbn1mgR/mgR and WT mice serving as controls. To determine conservation in human disease, we reanalyzed publicly available single-cell RNA sequencing data from ascending thoracic aortic aneurysm (ATAA) patients. ResultsAngII infusion induced progressive mortality beginning at 24 hours, with approximately 60% survival at 72 hours and nearly no survival by 8 days in Fbn1mgR/mgR mice. At this pre-rupture time point, OPN showed prominent upregulation at both mRNA and protein levels in ascending aortic tissues compared to controls. Immunofluorescence staining revealed increased OPN expression in the aortic wall, particularly in regions exhibiting structural deterioration. Reanalysis of human ATAA single-cell data showed elevated OPN expression compared to controls, with enrichment in immune cell populations, especially macrophages. Within the macrophage compartment, subcluster analysis identified a stress-responsive subpopulation (MC1) that was markedly expanded and almost exclusively composed of ATAA-derived cells, representing the primary source of OPN upregulation. ConclusionsOPN upregulation represents a conserved molecular signature of the pre-rupture state in TAA across mice and humans. Our mode, which enables predictable rupture timing, allowed the capture of acute pre-rupture molecular changes, suggesting OPN as a potential biomarker for predicting imminent aortic rupture.

molecular biology↗

bioRxiv2026

Label-free Raman imaging defines distinct cell populations in human skin

Understanding cellular heterogeneity in human skin is crucial for regenerative medicine and tissue engineering. In this study, we applied label-free Raman imaging to visualize molecular features corresponding to the three-dimensional architecture of the epidermis. Spatially resolved Raman spectra, combined with multivariate data analysis, enabled the identification of cell-layer-specific molecular signatures. Based on the region-specific spectra analysis, component C5 was predominantly localized to the basal layer within rete ridges and was characterized by {beta}-sheet-enriched keratin features. This spatially restricted distribution reflects the molecular microenvironment of epidermal stem cell niches, suggesting that C5 may serve as a biomarker for basal stem cell populations associated with skin undulations. These findings provide insight into the molecular basis of epidermal architecture and demonstrate the potential of Raman spectroscopy as a label-free tool for evaluating stem cell localization and differentiation status.

bioengineering↗

bioRxiv2024

The disruption of CtBP regulates DUX-dependent and -independent genetic program for the 2-cell-like state in murine embryonic stem cells

After fertilization, maternally deposited mRNA is cleared, and de novo mRNA is transcribed from the zygotic genome through zygotic genome activation (ZGA), a process known as maternal-to-zygotic transition (MZT) occurring in the mouse at 2-cell (2C) stage. 2C-like cells (2CLCs) marked by MERVL expression are transcriptionally similar to 2C embryos spontaneously emerge from mouse embryonic stem cells (mESCs). Although the emergence of 2CLCs completely depends on DUX function, a recent knockout study clearly showed that DUX is dispensable for mouse embryos, suggesting that DUX-independent molecular pathways are not recapitulated in 2CLCs. We present here that the disruption of C-terminal binding protein 1/2 (Ctbp1/2) activates DUX-dependent and -independent molecular pathway associated with the development of early mouse embryos mediated by the upregulation of Preferentially expressed antigen of melanoma family-like 7 (PRAMEL7). Furthermore, the abnormality of the gene expression profile caused by Dux KO is partially rescued by the overexpression of PRAMEL7 in mESCs. Our study provides new insights into the DUX-independent molecular pathway for the activation of early embryonic genes in mESCs.

cell biology↗

bioRxiv2023

Novel Insights into the Aortic Mechanical Properties of Mice Modeling Hereditary Aortic Diseases

OBJECTIVEHereditary aortic diseases (hADs) increase the risk of aortic dissections and ruptures. Recently, we have established an objective approach to measure the rupture force of the murine aorta, thereby explaining the outcomes of clinical studies and assessing the added value of approved drugs in vascular Ehlers-Danlos syndrome (vEDS). Here, we applied our approach to six additional mouse hAD models. APPROACH AND RESULTWe used two mouse models of Marfan syndrome (MFS) as well as one smooth-muscle-cell-specific knockout (SMKO) of Efemp2 and three CRISPR/Cas9-engineered knock-in models (Ltbp1, Mfap4, and Timp1). One of the two MFS models was subjected to 4-week-long losartan treatment. Per mouse, three rings of the thoracic aorta were prepared, mounted on a tissue puller, and uniaxially stretched until rupture. The aortic rupture force of the SMKO and both MFS models was significantly lower compared with wild-type mice but in both MFS models higher than in mice modeling vEDS. In contrast, the Ltbp1, Mfap4, and Timp1 knock-in models presented no impaired aortic integrity. As expected, losartan treatment reduced aneurysm formation but surprisingly had no impact on the aortic rupture force of our MFS mice. CONCLUSIONSOur read-out system can characterize the aortic biomechanical integrity of mice modeling not only vEDS but also related hADs, allowing the aortic-rupture-force- focused comparison of mouse models. Furthermore, aneurysm progression alone may not be a sufficient read-out for aortic rupture, as antihypertensive drugs reducing aortic dilatation might not strengthen the weakened aortic wall. Our results may enable identification of improved medical therapies of hADs. HighlightsO_LIAssay to measure the aortic rupture force as read-out for the biomechanical integrity identified weakened murine thoracic aorta prior to micro- and macroscopic changes in Fbn1+/C1041G mice. C_LIO_LIDespite reducing aneurysm growth, losartan treatment did not have any impact on the aortic rupture force of Fbn1mgR/mgR mice modeling MFS. C_LIO_LISmooth-muscle-cell-knock-out of Efemp2 significantly impaired the rupture force of the murine ascending aorta. C_LIO_LIAortic rupture force measurements could clarify the causality of novel candidate gene(s)/variant(s) in mouse models of aortic diseases. C_LI Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=139 SRC="FIGDIR/small/553452v2_ufig1.gif" ALT="Figure 1"> View larger version (32K): org.highwire.dtl.DTLVardef@a29d79org.highwire.dtl.DTLVardef@10a272org.highwire.dtl.DTLVardef@19071forg.highwire.dtl.DTLVardef@122ab40_HPS_FORMAT_FIGEXP M_FIG C_FIG

pathology↗