Biology subjects

Yamaguchi, M.

Publications and source records attributed to Yamaguchi, M..

At least 37 records · Page 2Linked to original sources

bioRxiv2024

An efficient inducible model for the control of gene expression in renin cells

BackgroundFate mapping and genetic manipulation of renin cells have relied on either non-inducible Cre lines that can introduce developmental effects of gene deletion or BAC transgene-based inducible models that may be prone to spurious and/or ectopic gene expression. MethodsWe generated an inducible mouse model in which CreERT2 is under the control of the endogenous Akr1b7 gene, an independent marker of renin cells. ResultsWe evaluated the pattern of Cre expression in Akr1b7CreERT2/+;R26RmTmG/+ mice in which Akr1b7+/renin+ cells become GFP+ upon tamoxifen administration. At E18.5 and P5, GFP was found in Juxtaglomerular cells, along the arterioles, and in the glomerular mesangium. In adult kidneys, GFP was present mainly in Juxtaglomerular cells. In mice treated with captopril and a low sodium diet to induce recruitment of renin cells, GFP extended along the afferent arterioles and in the mesangium. In addition, we deleted renin in adult mice and found a marked reduction in kidney renin expression and mean arterial pressure in mutant animals. When subjected to a homeostatic threat, mutant mice were unable to recruit renin+ cells. Most importantly, mice with renin deletion induced in the adult developed concentric vascular hypertrophy ruling out potential developmental effects on the vasculature due to the lack of renin. ConclusionsRenin can be efficiently and specifically deleted in renin cells in adult life using our conditional model. Akr1b7CreERT2 mice constitute an excellent model for the fate mapping of renin cells and for the spatial and temporal control of gene expression in renin cells.

physiology↗

bioRxiv2024

Kaempferol exerts anti-inflammatory effects by accelerating Treg development via AhR-mediated and PU.1/IRF4-dependent transactivation of the Aldh1a2/RALDH2 gene in dendritic cells

Retinaldehyde dehydrogenase 2 encoded in the Aldh1a2 gene (RALDH2) is expressed in intestinal dendritic cells (DCs) in mesenteric lymph nodes (MLNs) and plays a crucial role in Treg development by producing retinoic acid. In the present study, we screened food ingredients and identified kaempferol, a flavonoid, as the compound that most effectively up-regulated RALDH2 expression in DCs. The development of Foxp3+ cells from OT-II-derived naive CD4+ T cells was enhanced by a co-culture with OVA peptide-pulsed bone marrow-derived DCs (BMDCs) in the presence of kaempferol or by a pre-treatment of BMDCs with kaempferol. The involvement of the aryl hydrocarbon receptor (Ahr) in the effects of kaempferol on Aldh1a2 expression was demonstrated by in vitro experiments using siRNA and various agonistic or antagonistic compounds of AhR. AhR suppressed Aldh1a2 gene expression and kaempferol inhibited the AhR activity by functioning as an antagonist of AhR. The kaempferol treatment also increased the protein levels of PU.1 and IRF4, which are essential for transcription of the Aldh1a2 gene in DCs, and accelerated the subsequent recruitment of PU.1 to the Aldh1a2 gene. The kaempferol-induced increase in PU.1 protein levels occurred in an AhR-dependent and transcription-independent manner, whereas the kaempferol treatment transactivated the Irf4 gene in DCs. The frequency of DCs exhibiting RALDH2 activity in the MLNs of mice was increased by the intraperitoneally (i.p.) administration of an AhR antagonist or by the oral administration of astragalin, a 3-O-glucoside of kaempferol. We also observed an increase in Tregs in the Peyers patches of C57BL/6 mice i.p. administered kaempferol-treated BMDCs. We utilized an OVA-induced food allergy model of Balb/c mice to examine the effects of kaempferol in vivo and confirmed that the rapid decrease in body temperature and allergic diarrhea observed just after the OVA challenge were significantly suppressed in mice administered kaempferol.

immunology↗

bioRxiv2023

The similarities in microbial and chemical patterns of fermentation in two open environments were promoted by using 150-year-old Nukadoko as starters.

Nukadoko, a fermented rice bran employed in traditional Japanese pickling, uses lactic acid bacteria to ferment vegetables. Here, we report the microbial and chemical data of a mixture of matured 150-year-old nukadoko and commercially available rice bran placed in two open environments over 29 days. Across the two environments, Loigolactobacillus was identified as the dominant microbial genera in the later stages of fermentation in nukadoko. The period of increase in the relative abundance of Loigolactobacillus correlated with a decrease in pH and Oxidation-Reduction Potential (ORP) values. While the two environments showed a difference in the rate of change in microbial diversity, they shared the common process through which Loigolactobacillus outcompeted adventitious bacteria in nukadoko, as indicated by the alpha and beta diversity index. Thus, the similarities in microbial and chemical data across two open environments during fermentation using starters indicate that starters contribute to the stability of fermentation in open environments.

microbiology↗

bioRxiv2023

Gut microbiota-mediated alleviation of dextran sulfate sodium-induced colitis in mice.

SummaryWe found a disease-resistant BALB/c substrain with lower susceptibility to DSS-induced colitis. Gut microbiota analysis using 16S rRNA analysis observed the expansion of butyrate-producing Roseburia species in mice with decreased susceptibility to the disease. Gut dysbiosis characterized by an imbalanced microbiota is closed involved in the pathogenesis of a widespread gastrointestinal inflammatory disorder, inflammatory bowel disease. However, it is unclear how the complex intestinal microbiota affects resistance to mucosal inflammation. Here, we showed differences in the susceptibility of inbred BALB/c mice from three main distributors of laboratory animals to colitis; clinical symptoms, such as weight loss, disease activity index score, and colon shortening were assessed. Analysis of the gut microbiota using 16S rRNA sequencing revealed clear separation of the gut microbial composition among mice from the vendors. Notably, the abundance of the phylum Actinobacteriota was strongly associated with disease activity. We also observed the expansion of butyrate-producing Roseburia species in mice with decreased susceptibility to the disease. Further cohousing experiments showed that variation in clinical outcomes was more correlated with the gut microbiota than genetic variants among substrains from different suppliers. Targeting butyrate-producing bacteria could have therapeutic potential for ulcerative colitis.

microbiology↗

bioRxiv2023

Human USP18 protects diverse cancer lineages from Type I Interferon independently of its canonical catalytic function

Precise temporal regulation of Type I interferon signaling is imperative to effectively fight infections and cancerous cells without triggering autoimmunity. The key negative regulator of Type I interferon signaling is ubiquitin-specific protease 18 (USP18). USP18 cleaves interferon-inducible ubiquitin-like modifications through its canonical catalytic function and directly inhibits interferon receptor signaling through its scaffold role. USP18 loss-of-function dramatically impacts autoimmune disease, viral susceptibility, and cancer cell survival. However, the relative contribution of catalytic versus scaffold function is unresolved and must be determined to design effective therapeutics targeting USP18. To precisely delineate individual contribution, we evaluated the functional impact of single amino acid mutations that disrupt catalytic or scaffold activity. Here we demonstrate catalytic activity does not contribute to cell autonomous Type I interferon sensitivity across multiple cancer cell lineages. Furthermore, introducing a patient-derived mutation that disrupts scaffold function is sufficient to inhibit cancer growth. These findings establish a fundamental mechanistic basis for USP18 therapeutic design across diseases. OVERVIEWO_LIUSP18 is the key negative regulator of Type I interferon signaling in humans, mediating autoimmune disease, viral susceptibility, and cancer cell survival. C_LIO_LIUSP18 cleaves interferon-inducible ubiquitin-like modifications through its canonical catalytic function and attenuates interferon receptor signaling through its scaffold role. C_LIO_LIDelineating the contribution of each function is critical to resolve the mechanistic basis of interferon regulation and enable the development of therapeutics targeting USP18. C_LIO_LIWe demonstrate that cell intrinsic interferon sensitivity is not mediated by loss of catalytic activity. However, disruption of scaffold function by a patient-specific mutation inhibits cancer cell growth. C_LIO_LIFurthermore, we discovered that canonical catalytic activity is surprisingly inefficient in human cells. C_LIO_LIThese results clarify a fundamental mechanism of immune regulation and cancer cell survival in humans. C_LI O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=117 SRC="FIGDIR/small/533924v3_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@d0a353org.highwire.dtl.DTLVardef@192a09dorg.highwire.dtl.DTLVardef@16eb296org.highwire.dtl.DTLVardef@8e98a3_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2023

Assessing the performance of the Cell Painting assay across different imaging systems

Quantitative microscopy is a powerful method for performing phenotypic screens from which image-based profiling can extract a wealth of information, termed profiles. These profiles can be used to elucidate the changes in cellular phenotypes across cell populations from different patient samples or following genetic or chemical perturbations. One such image-based profiling method is the Cell Painting assay, which provides morphological insight through the imaging of eight cellular compartments. Here, we examine the performance of the Cell Painting assay across multiple high-throughput microscope systems and find that all are compatible with this assay. Furthermore, we determine independently for each microscope system the best performing settings, providing those who wish to adopt this assay an ideal starting point for their own assays. We also explore the impact of microscopy setting changes in the Cell Painting assay and find that few dramatically reduce the quality of a Cell Painting profile, regardless of the microscope used.

cell biology↗

bioRxiv2022

Wsc1 acts as a piezosensor in Saccharomyces cerevisiae, enhancing glycerol efflux via aquaglyceroporin Fps1 in response to high hydrostatic pressure

The fungal cell wall is the initial barrier for the fungi against diverse external stresses, such as osmolarity changes, harmful drugs, and mechanical injuries. This study explores the roles of osmoregulation and the cell wall integrity (CWI) pathway in response to high hydrostatic pressure in the yeast Saccharomyces cerevisiae. We demonstrate the roles of the transmembrane mechanosensor Wsc1 and aquaglyceroporin Fps1 in a general mechanism to maintain cell growth under high-pressure regimes. The promotion of water influx into cells at 25 MPa, as evident by an increase in cell volume and a loss of the plasma membrane eisosome structure, promotes the activation of Wsc1, an activator of the CWI pathway. The downstream mitogen-activated protein kinase Slt2 was hyperphosphorylated at 25 MPa. Glycerol efflux increases via Fps1 phosphorylation, which is initiated by downstream components of the CWI pathway and contributes to the reduction in intracellular osmolarity under high pressure. The elucidation of the mechanisms underlying adaption to high pressure through the well-established CWI pathway could potentially translate to mammalian cells and provide novel insights into cellular mechanosensation.

cell biology↗

bioRxiv2022

Posteromedial cortical networks encode visuomotor prediction errors.

Predicting future events based on internal models is essential for animal survival. Predictive coding postulates that errors between prediction and observation in lower-order areas update predictions in higher-order areas through the hierarchy. However, it is unclear how predictive coding is implemented in the hierarchy of the brain. Herein, we report the neural mechanism of the hierarchical processing and transmission of bottom-up prediction error signals in the mouse cortex. Ca2+ imaging and electrophysiological recording in virtual reality revealed responses to visuomotor mismatches in the retrosplenial, dorsal visual, and anterior cingulate cortex. These mismatch responses were attenuated when mismatches became predictable through experience. Optogenetic inhibition of bottom-up signals reduced a behavioral indicator for prediction errors. Moreover, cellular-level mismatch responses were modeled by Bayesian inference using a state-space model. This study demonstrates hierarchical circuit organization underlying prediction error propagation, advancing the understanding of predictive coding in sensory perception and learning in the brain. O_FIG O_LINKSMALLFIG WIDTH=188 HEIGHT=200 SRC="FIGDIR/small/504075v2_ufig1.gif" ALT="Figure 1"> View larger version (82K): org.highwire.dtl.DTLVardef@1f03960org.highwire.dtl.DTLVardef@46df08org.highwire.dtl.DTLVardef@dc97ccorg.highwire.dtl.DTLVardef@7200ae_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2020

GP96 drives exacerbation of secondary bacterial pneumonia following influenza A virus infection

Influenza A virus (IAV) infection predisposes the host to secondary bacterial pneumonia, known as a major cause of morbidity and mortality during influenza epidemics. Analysis of interactions between IAV-infected human epithelial cells and Streptococcus pneumoniae revealed that infected cells ectopically exhibited the endoplasmic reticulum chaperon GP96 on the surface. Importantly, efficient pneumococcal adherence to epithelial cells was imparted by interactions with extracellular GP96 and integrin V, with the surface expression mediated by GP96 chaperone activity. Furthermore, abrogation of adherence was gained by chemical inhibition or genetic knockout of GP96, as well as addition of RGD peptide. Direct binding of extracellular GP96 and pneumococci was shown to be mediated by pneumococcal oligopeptide permease components. Additionally, IAV infection induced activation of calpains and Snail1, which are responsible for degradation and transcriptional repression of junctional proteins in the host, respectively, indicating increased bacterial translocation across the epithelial barrier. Notably, treatment of IAV-infected mice with the GP96 inhibitor enhanced pneumococcal clearance from lung tissues and ameliorated lung pathology. Taken together, the present findings indicate a viral-bacterial synergy in relation to disease progression and suggest a paradigm for developing novel therapeutic strategies tailored to inhibit pneumococcal colonization in an IAV-infected respiratory tract.

microbiology↗

bioRxiv2020

Sphingobium sp. SYK-6 syringate O-demethylase gene is regulated by DesX, unlike other vanillate and syringate catabolic genes regulated by DesR

Syringate and vanillate are the major metabolites of lignin biodegradation. In Sphingobium sp. strain SYK-6, syringate is O demethylated to gallate by consecutive reactions catalyzed by DesA and LigM, and vanillate is O demethylated to protocatechuate by a reaction catalyzed by LigM. The gallate ring is cleaved by DesB, and protocatechuate is catabolized via the protocatechuate 4,5-cleavage pathway. The transcriptions of desA, ligM, and desB are induced by syringate and vanillate, while that of ligM and desB are negatively regulated by the MarR-type transcriptional regulator DesR, which is not involved in desA regulation. Here we clarified the regulatory system for desA transcription by analyzing the IclR-type transcriptional regulator desX, located downstream of desA. Quantitative reverse transcription (RT)-PCR analyses of a desX mutant indicates that the transcription of desA was negatively regulated by DesX. In contrast, DesX was not involved in the regulation of ligM and desB. The ferulate catabolic genes (ferBA) under the control of a MarR-type transcriptional regulator FerC are located upstream of desA. RT-PCR analyses suggest that the ferB-ferA-SLG_25010-desA gene cluster consists of the ferBA operon and the SLG_25010-desA operon. Promoter assays reveal that a syringate- and vanillate-inducible promoter is located upstream of SLG_25010. Purified DesX bound to this promoter region, which overlaps with an 18-bp-inverted repeat sequence that appears to be essential for the DNA binding of DesX. Syringate and vanillate inhibited the DNA binding of DesX, indicating that these compounds are effector molecules of DesX. IMPORTANCESyringate is a major degradation product in the microbial and chemical degradation of syringyl lignin. Along with other low-molecular-weight aromatic compounds, syringate is produced by chemical lignin depolymerization. Converting this mixture into value-added chemicals using bacterial metabolism (i.e., biological funneling) is a promising option for lignin valorization. To construct an efficient microbial lignin conversion system, it is necessary to identify and characterize the genes involved in the uptake and catabolism of lignin-derived aromatic compounds and elucidate their transcriptional regulation. In this study, we found that the transcription of desA, encoding syringate O-demethylase in SYK-6, is regulated by an IclR-type of transcriptional regulator, DesX. The findings of this study, combined with our previous results on desR (a MarR transcriptional regulator that controls the transcription of ligM and desB), provide an overall picture of the transcriptional regulatory systems for syringate and vanillate catabolism in SYK-6.

microbiology↗

bioRxiv2020

Three-dimensional understanding of the morphological complexity of the human uterine endometrium

SummaryThe histological basis of the human uterine endometrium has been established by 2D observation. However, the fundamental morphology of endometrial glands is not sufficiently understood because these glands have complicated winding and branching patterns. To construct a big picture of endometrial gland structure, we performed tissue-clearing-based 3D imaging of human uterine endometrial tissue. Our 3D immunohistochemistry and 3D layer analyses revealed that endometrial glands formed a plexus network in the stratum basalis, similar to the rhizome of grass. We then extended our method to assess the 3D morphology of adenomyosis, a representative “endometrium-related disease”, and observed 3D morphological features including direct invasion of endometrial glands into the myometrium and an ant colony-like network of ectopic endometrial glands within the myometrium. Thus, 3D analysis of the human endometrium and endometrium-related diseases will be a promising approach to better understand the pathologic physiology of the human endometrium.Competing Interest StatementThe authors have declared no competing interest.View Full Text

pathology↗

bioRxiv2020

Genetic characterization of Streptococcus pyogenes emm 89 strains isolated in Japan from 2011 to 2019

Streptococcal toxic shock syndrome (STSS) caused by Streptococcus pyogenes emm89 strains has been increasing in several countries and reported to be linked with a recently emerged clade of emm89 strains, designated clade 3. In Japan, epidemiological and genetic information for emm89 strains remains elusive. In this study, we utilized emm89 strains isolated from both STSS (89 isolates) and non-STSS (72 isolates) infections in Japan from 2011 to 2019, and conducted whole-genome sequencing and comparative analysis, which resulted in classification of a large majority into clade 3 regardless of disease severity. In addition, STSS-associated genes and SNPs were found in clade 3 strains, including mutations of streptokinase (Ska), control of virulence sensor (CovS), serum opacity factor (SOF), sortase (SrtB), and fibronectin-binding protein F1 (PrtF1), and absence of the hylP1 gene encoding hyaluronidase. These findings provide insights into notable genetic features of emm89 strains.

microbiology↗

bioRxiv2019

Dual Role of Jam3b in Early Hematopoietic and Vascular Development

In order to efficiently derive hematopoietic stem cells (HSCs) from pluripotent precursors, it is crucial to understand how mesodermal cells acquire hematopoietic or endothelial identity due to their close developmental connection. Although Npas4 has been recently identified as a conserved master regulator of hemato-vascular development, the molecular mechanisms underlying the cell fate divergence between hematopoietic and vascular endothelial cells are still unclear. Here, we show in zebrafish that the divergence of hematopoietic and vascular endothelial cells in mesodermal cells is regulated by Junctional adhesion molecule 3b (Jam3b) via two independent signaling pathways. Mutation of jam3b led to the reduction of npas4l expression in the posterior lateral plate mesoderm and defect of both hematopoietic and vascular development. Mechanistically, we uncover that Jam3b promotes endothelial specification by regulating npas4l expression through the repression of the Rap1a-Erk signaling cascade. Jam3b subsequently promotes hematopoietic development including HSCs by regulating lrrc15 expression in endothelial precursors through the activation of an integrin-dependent signaling cascade. Our data provide insight into the divergent mechanisms for instructing hematopoietic or vascular fates from mesodermal cells.

developmental biology↗

bioRxiv2019

Transcriptomic profiling of Streptococcus pyogenes M1T1 strain in a mouse model of necrotizing fasciitis

Streptococcus pyogenes is a major cause of necrotizing fasciitis, a life-threatening subcutaneous soft-tissue infection. At the host infection site, the local environment and interaction between host and bacteria affect bacterial gene-expression profiles, but the S. pyogenes gene-expression pattern in necrotizing fasciitis remains unknown. In this study, we used a mouse model of necrotizing fasciitis and performed RNA-sequencing (RNA-seq) analysis of S. pyogenes M1T1 strain 5448 by using infected hindlimbs obtained at 24, 48, and 96 h post-infection. The RNA-seq analysis identified 483 bacterial genes whose expression was consistently altered in the infected hindlimbs as compared to their expression under in vitro conditions. The consistently enriched genes during infection included 306 genes encoding molecules involved in virulence, carbohydrate utilization, amino acid metabolism, trace-metal transport and vacuolar ATPase transport system. Surprisingly, drastic upregulation of 3 genes, encoding streptolysin S precursor (sagA), cysteine protease (speB), and secreted DNase (spd), was noted in the mouse model of necrotizing fasciitis (log2 fold-change values: >6.0, >9.4, and >7.1, respectively). Conversely, the consistently downregulated genes included 177 genes, containing genes associated with oxidative-stress response and cell division. These results suggest that S. pyogenes in necrotizing fasciitis changes its metabolism, decreases cell proliferation, and upregulates the expression of major toxins. Our findings could provide critical information for developing novel treatment strategies and vaccines for necrotizing fasciitis.\n\nAuthor summaryNecrotizing fasciitis, a life-threatening subcutaneous soft-tissue infection, principally caused by a Streptococcus pyogenes. At infection sites in hosts, bacterial pathogens are exposed to drastically changing environmental conditions and alter global gene expression patterns for survival and pathogenesis. However, there is no previous report about transcriptomic profiling of S. pyogenes in the necrotizing fasciitis. Here, we conducted comprehensive gene-expression analyses of S. pyogenes in the mouse model of necrotizing fasciitis at three distinct time points during infection. Our results indicated that S. pyogenes drastically upregulates the expression of virulence-associated genes and shifts metabolic-pathway usage during infection. The high-level expressions in particular of toxins, such as cytolysins, proteases, and nucleases, were observed at infection sites. In addition, the consistently enriched genes identified here included genes for metabolism of arginine and histidine, and carbohydrate uptake and utilization. Conversely, the genes associated with oxidative-stress response and cell division were consistently downregulated in the mouse model of necrotizing fasciitis. These data will provide useful information necessary for establishing novel treatment strategies (166 words).

microbiology↗

bioRxiv2019

Towards HCP-Style Macaque Connectomes: 24-Channel 3T Multi-Array Coil, MRI Sequences and Preprocessing

Macaque monkeys are an important model species for understanding cortical organization of primates, yet tools and methods for noninvasive image acquisition (e.g. MRI RF coils and pulse sequence protocols) and image data preprocessing have lagged behind those developed for humans. To resolve the structural and functional characteristics of the relatively thin macaque cortex, high spatial, temporal, and angular resolutions are required while maintaining high signal-to-noise ratio to ensure good image quality. To address these challenges, we developed a macaque 24-channel receive coil for 3-T MRI with parallel imaging capabilities. This coil enabled adaptation of the Human Connectome Project (HCP) image acquisition protocols to the macaque brain. We also adapted HCP preprocessing methods optimized for the macaque brain, including spatial minimal preprocessing of structural, functional MRI (fMRI), and diffusion MRI (dMRI). The coil provided high signal-to-noise ratio and high efficiency in data acquisition, allowing four- and five-fold acceleration for dMRI and fMRI, respectively. Automated parcellation of cortex, reconstruction of cortical surface, removal of artefacts and nuisance signals in fMRI, and distortion correction of dMRI performed well, and the overall quality of basic neurobiological measures was comparable with those for the HCP. The resulting HCP-style in vivo macaque MRI data show considerable promise for analyzing cortical architecture and functional and structural connectivity using advanced methods that have previously only been available for humans.\n\nHighlights[tpltrtarr] 24-channel 3T MR receive coil designed for the smaller macaque brain.\n[tpltrtarr]In vivo macaque imaging protocols adapted according to guidelines from the HCP.\n[tpltrtarr]Parallel imaging yields five- and four-fold acceleration in fMRI and dMRI sampling.\n[tpltrtarr]HCPs minimal preprocessing and denoising pipelines adapted for macaques.\n[tpltrtarr]The multi-modal MRI data show considerable promise for HCP-style analyses.

neuroscience↗

bioRxiv2019

Streptococcus pneumoniae evades host cell phagocytosis and limits host mortality through its cell wall anchoring protein PfbA

Streptococcus pneumoniae is a Gram-positive bacterium belonging to the oral streptococcus species, mitis group. This pathogen is a leading cause of community-acquired pneumonia, which often evades host immunity and causes systemic diseases, such as sepsis and meningitis. Previously, we reported that PfbA is a {beta}-helical cell surface protein contributing to pneumococcal adhesion to and invasion of human epithelial cells in addition to its survival in blood. In the present study, we investigated the role of PfbA in pneumococcal pathogenesis. Phylogenetic analysis indicated that the pfbA gene is specific to S. pneumoniae within the mitis group. Our in vitro assays showed that PfbA inhibits neutrophil phagocytosis, leading to pneumococcal survival. We found that PfbA activates NF-{kappa}B through TLR2, but not TLR4. In addition, TLR2/4 inhibitor peptide treatment of neutrophils enhanced the survival of the S. pneumoniae {Delta}pfbA strain as compared to a control peptide treatment, whereas the treatment did not affect survival of a wild-type strain. In a mouse pneumonia model, the host mortality and level of TNF- in bronchoalveolar lavage fluid were comparable between wild-type and {Delta}pfbA-infected mice, while deletion of pfbA increased the bacterial burden in bronchoalveolar lavage fluid. In a mouse sepsis model, the {Delta}pfbA strain demonstrated significantly increased host mortality and TNF- levels in plasma, but showed reduced bacterial burden in lung and liver. These results indicate that PfbA may contribute to the success of S. pneumoniae species by inhibiting host cell phagocytosis, excess inflammation, and mortality.\n\nImportanceStreptococcus pneumoniae is often isolated from the nasopharynx of healthy children, but the bacterium is also a leading cause of pneumonia, meningitis, and sepsis. In this study, we focused on the role of a cell wall anchoring protein, PfbA, in the pathogenesis of S. pneumoniae-related disease. We found that PfbA is a pneumococcus-specific anti-phagocytic factor that functions as a TLR2 ligand, indicating that PfbA may represent a pneumococcal-specific therapeutic target. However, a mouse pneumonia model revealed that PfbA deficiency reduced the bacterial burden, but did not decrease host mortality. Furthermore, in a mouse sepsis model, PfbA deficiency increased host mortality. These results suggest that S. pneumoniae optimizes reproduction by regulating host mortality through PfbA; therefore, PfbA inhibition would not be an effective strategy for combatting pneumococcal infection. Our findings underscore the challenges involved in drug development for a bacterium harboring both commensal and pathogenic states.

microbiology↗

bioRxiv2018

Opposing roles of dopamine receptor D1- and D2-expressing neurons in the anteromedial olfactory tubercle in acquisition of place preference in mice

Olfaction induces adaptive motivated behaviors. Odors associated with food induce attractive behavior, whereas those associated with dangers induce aversive behavior. We previously reported that learned odor-induced attractive and aversive behaviors accompany activation of the olfactory tubercle (OT) in a domainand cell type-specific manner. Odor cues associated with a sugar reward induced attractive behavior and c-fos expression in the dopamine receptor D1-expressing neurons (D1 neurons) in the anteromedial OT. In contrast, odor cues associated with electrical shock induced aversive behavior and c-fos expression in the D2 neurons in the anteromedial OT, as well as the D1 neurons in the lateral OT. Here, we investigated whether the D1 and D2 neurons in the anteromedial OT play distinct roles in attractive or aversive behaviors, using optogenetic stimulation and real-time place preference (RTPP) tests. Mice expressing ChETA (ChR2/E123T)-EYFP in the D1 neurons in the anteromedial OT spent a longer time in the photo-stimulation side of the place preference chamber than the control mice expressing EYFP. On the other hand, upon optogenetic stimulation of the D2 neurons in the anteromedial OT, the mice spent a shorter time in the photo-stimulation side than the control mice. Local neural activation in the anteromedial OT during the RTPP tests was confirmed by c-fos mRNA expression. These results suggest that the D1 and D2 neurons in the anteromedial OT play distinct roles in attractive and aversive behaviors, respectively.

neuroscience↗

bioRxiv2018

GABAergic neurons in the olfactory cortex projecting to the lateral hypothalamus in mice

Olfaction guides goal-directed behaviours including feeding. To investigate how central olfactory neural circuits control feeding behaviour in mice, we performed retrograde tracing from the lateral hypothalamus (LH), an important feeding centre. We observed a cluster of retrogradely labelled cells distributed in the posteroventral region of the olfactory peduncle. Histochemical analyses revealed that a majority of these retrogradely labelled projection neurons expressed glutamic acid decarboxylase 65/67 (GAD65/67), but not vesicular glutamate transporter 1 (VGluT1). We named this region with GABAergic projection neurons the ventral olfactory nucleus (VON) to discriminate it from the conventional olfactory peduncle. VON neurons were less immunoreactive for DARPP-32, a striatal neuron marker, in comparison to those in the olfactory tubercle and nucleus accumbens, which distinguished the VON from the ventral striatum. Fluorescent labelling confirmed synaptic contacts between VON neurons and olfactory bulb projection neurons. Rabies-virus-mediated trans-synaptic labelling revealed that VON neurons received synaptic inputs from the olfactory bulb, other olfactory cortices, horizontal limb of the diagonal band, and prefrontal cortex. Collectively, these results identified novel GABAergic projection neurons in the olfactory cortex that can integrate olfactory sensory and top-down inputs and send inhibitory output to the LH, which may contribute to forming odour-guided LH-related behaviours.

neuroscience↗