Biology subjects

Watanabe, H.

Publications and source records attributed to Watanabe, H..

At least 55 records · Page 3Linked to original sources

bioRxiv2022

Cyb5r3-based mechanism and reversal of secondary failure to sulfonylurea

Sulfonylureas (SU) are effective and affordable anti-diabetic drugs. But chronic use leads to secondary failure, limiting their utilization. The mechanism of secondary failure is unknown. Here we identify Cyb5r3 downregulation as a mechanism of SU failure and successfully reverse it. Chronic exposure to SU impairs Cyb5r3 levels and reduces islet glucose utilization with a metabolomics signature characterized by low acetyl-CoA and amino acid levels. Cyb5r3 engages in a glucose-dependent interaction that stabilizes glucokinase (Gck) to maintain glucose utilization. Accordingly, activating Gck mutations in patients with hyperinsulinemia reduce Cyb5r3 binding, whereas inactivating MODY mutations increase it, providing evidence for a role of Cyb5r3 in determining flux through Gck. The Cyb5r3 activator tetrahydroindenoindole (THII) rescues secondary failure to SU in an animal model of chronic SU treatment and restores insulin secretion from ex vivo islets. We conclude that Cyb5r3 loss-of-function is a key factor in the secondary failure to SU and a potential target for its prevention, which may lead to a rehabilitation of SU use in diabetes.

physiology↗

bioRxiv2022

N1-methylpseudouridine-incorporated mRNA enhances exogenous protein expression and suppresses immunogenicity in primary human fibroblast-like synoviocytes

Studies conducted using murine arthritis models have indicated that the use of in vitro-transcribed messenger RNA (IVT mRNA) is an effective therapeutic approach for joint diseases. However, the use of IVT mRNA in human synovial cells has not been widely studied. Recently, the outbreak of the novel coronavirus disease has accelerated the development of innovative mRNA vaccines such as those containing a modified nucleic acid, N1-methylpseudouridine-5'-triphosphate (m1{psi}). IVT mRNA is an attractive tool for biological experiments and drug discovery. To verify the protein expression of IVT mRNA in vitro, primary cultured human fibroblast-like synoviocytes (FLS) were transfected with enhanced green fluorescent protein (EGFP) mRNA with or without m1{psi} incorporation. EGFP was detected using western blotting and fluorescence microscopy. A multiplex assay was performed to comprehensively understand IVT mRNA-induced immunogenicity. FLS transfected EGFP mRNA containing m1{psi} generated higher levels of EGFP than unmodified EGFP mRNA or control RNAs. The multiplex assay of the FLS culture supernatant revealed that concentrations of IL-6, TNF-, and CXCL10 were upregulated by unmodified EGFP mRNA, whereas they were suppressed by EGFP mRNA with m1{psi}. Overall, m1{psi} incorporation enhanced protein expression and decreased cytokine expressions in primary cultured FLS. The findings may contribute to arthritis research.

molecular biology↗

bioRxiv2022

Triple Notch/Tgfβ/FoxO1 blockade converts multiple intestinal sub-lineages into β-like cells and lowers glycemia in diabetic animals

Insulin is the essential treatment of Type 1 (T1D) and is often used in Type 2 Diabetes. For nearly five decades, efforts have been focused on replenishing {beta}-cells in T1D patients as a more durable treatment. Gut endocrine cells can be converted into insulin-producing cells, but their numbers are limited. In this study we report that insulin-immunoreactive cells with Paneth/goblet cell features are present in human fetal intestine, in addition to enteroendocrine cells. Accordingly, lineage tracing experiments show that, besides enterochromaffin cells, the Paneth/goblet lineage can undergo conversion to the insulin lineage upon genetic or pharmacologic Foxo1 ablation in mice. We leveraged these data to design a screening platform in organoids to accurately quantitate {beta}-like cell reprogramming and fine-tune a combination treatment to increase the efficiency of the conversion process by expanding the intestinal secretory lineage. We identified a triple blockade of FoxO1, Notch, and Tgf{beta} that, when tested in insulin-deficient diabetic animals resulted in a near-normalization of glucose levels, associated with the appearance of gut insulin-producing cells. The findings illustrate a therapeutic approach to replace insulin treatment in diabetes.

cell biology↗

bioRxiv2022

Transcriptional circuitry of NKX2-1 and SOX1 defines an unrecognized lineage subtype of small cell lung cancer

RationaleThe current molecular classification of small cell lung cancer (SCLC) based on expression of four lineage transcription factors still leaves its major subtype SCLC-A as a heterogeneous group, necessitating more precise characterization of lineage subclasses. ObjectivesTo refine the current SCLC classification with epigenomic profiles and to identify features of the re-defined SCLC subtypes. MethodsWe performed unsupervised clustering of epigenomic profiles on 25 SCLC cell lines. Functional significance was evaluated by cell growth, apoptosis and xenograft using CRISPR-Cas9-mediated deletion. The specific cistromic profiles by ChIP-seq and its functional transcriptional partners using co-immunoprecipitation followed by mass spectrometry were determined. Rb1fl/flTrp53fl/fl and Rb1fl/flNkx2-1fl/fl mouse models were engineered to explore the function of Nkx2-1 in tumor initiation and differentiation. H3K27ac profiles were analyzed to reveal 6 human SCLC specimen and 20 mice tumors epigenomic landscapes. Measurements and Main ResultsWe identified an epigenomic subclusters of the major SCLC-A subtype, named SCLC-A and SCLC-A{sigma}. SCLC-A was characterized by the presence of a super-enhancer at the NKX2-1 locus, which was observed in human SCLC specimens and a murine SCLC model. We found NKX2-1, a dual lung and neural lineage factor, is uniquely relevant in SCLC-A. We further found maintenance of this neural identity in SCLC-A is mediated by collaborative transcriptional activity with another neuronal transcriptional factor SOX1. ConclusionsWe comprehensively describe an additional epigenomic heterogeneity of the major SCLC-A subtype, and define SCLC-A subtype by the core regulatory circuitry representing NKX2-1 and SOX1 super-enhancers and their functional collaborations to maintain neuronal linage state.

molecular biology↗

bioRxiv2022

Entamoeba histolytica EHD1 is involved in mitosome-endosome contact

Inter-organellar crosstalk is often mediated by membrane contact sites (MCSs), which are zones where participating membranes come within a proximity of 30 nm. MCSs have been found in organelles including the endoplasmic reticulum, Golgi bodies, endosomes, and mitochondria. Despite its seeming ubiquity, reports of MCS involving mitochondrion-related organelles (MROs) present in a few anaerobic parasitic protozoa remain lacking. Entamoeba histolytica, the etiological agent of amoebiasis, possesses an MRO called mitosome. We previously discovered several Entamoeba-specific transmembrane mitosomal proteins (ETMPs) from in silico and cell biological analyses. One of them, ETMP1 (EHI_175060), was predicted to have one transmembrane domain and two coiled-coil regions, and was demonstrated to be mitosome membrane-integrated based on carbonate fractionation and immunoelectron microscopy (IEM) data. Immunoprecipitation analysis detected a candidate interacting partner, EH-domain containing protein (EHD1, EHI_105270). We expressed HA-tagged EHD1 in E. histolytica and subsequent immunofluorescence and IEM data indicated an unprecedented MCS between the mitosome and the endosome. Live imaging of GFP-EHD1 expressing strain demonstrated that EHD1 is involved in early endosome formation, and is observed in MCS between endosomes of various sizes. In vitro assay using recombinant His-EHD1 demonstrated ATPase activity. MCSs are involved in lipid transfer, ion homeostasis, and organelle dynamics. The serendipitous discovery of the ETMP1 interacting partner EHD1, led to the observation of the mitosome-endosome contact site in E. histolytica. It opened a new view of how the relic mitochondria of Entamoeba may likewise be involved in organelle crosstalk, a conserved feature of mitochondria and other organelles in general.

cell biology↗

bioRxiv2021

Genomic characteristics of recently recognized Vibrio cholerae El Tor lineages associated with cholera in Bangladesh, 1991-2017

Comparative genomic analysis of Vibrio cholerae El Tor associated with endemic cholera in Asia revealed two distinct lineages, one dominant in Bangladesh and the other in India. An in depth whole genome study of V. cholerae El Tor clinical strains isolated during endemic cholera in Bangladesh (1991 - 2017) included reference genome sequence data obtained online. Core genome phylogeny established using single nucleotide polymorphisms (SNPs) showed V. cholerae El Tor strains comprised two lineages, BD-1 and BD-2, which, according to Bayesian phylodynamic analysis, originated from paraphyletic group BD-0 around 1981. BD-1 and BD-2 lineages overlapped temporally but were negatively associated as causative agents of cholera 2004-2017. Genome wide association study (GWAS) revealed 140 SNPs and 31 indels, resulting in gene alleles unique to BD-1 and BD-2. Regression analysis of root to tip distance and year of isolation indicated early BD-0 strains at the base, whereas BD-1 and BD-2 subsequently emerged and progressed by accumulating SNPs. Pangenome analysis provided evidence of gene acquisition by both BD-1 and BD-2, of which six crucial proteins of known function were predominant in BD-2. BD-1 and BD-2 diverged and have distinctively different genomic traits, namely heterogeneity in VSP-2, VPI-1, mobile elements, toxin encoding elements, and total gene abundance. In addition, the observed phage-inducible chromosomal island-like element (PLE1), and SXT ICE elements (ICETET) in BD-2 presumably provided a fitness advantage for the lineage to outcompete BD-1 as the etiological agent of the endemic cholera in Bangladesh, with implications for global cholera epidemiology. ImportanceCholera is a global disease with specific reference to the Bay of Bengal Ganges Delta where Vibrio cholerae O1 El Tor, causative agent of the disease showed two circulating lineages, one dominant in Bangladesh and the other in India. Results of in-depth genomic study of V. cholerae associated with endemic cholera during the past 27 years (1991 - 2017) indicate emergence and succession of the two lineages, BD-1 and BD-2, arising from a common ancestral paraphylatic group, BD-0, comprising the early strains and short-term evolution of the bacterium in Bangladesh. Among the two V. cholerae lineages, BD-2 supersedes BD-1 and is predominant in the most recent endemic cholera in Bangladesh. The BD-2 lineage contained significantly more SNPs and indels, and showed richness in gene abundance, including antimicrobial resistance genes, gene cassettes, and PLE to fight against bacteriophage infection, acquired over time. These findings have important epidemic implications at a global scale.

genomics↗

bioRxiv2021

Stress-impaired reward pathway promotes distinct feeding behavior patterns

Psychosocial stress can impact feeding behavior outcomes. Although many studies have examined alterations to food intake, little is known about how stress affects feeding behavior patterns. To determine the impact of psychological stress on feeding behavior patterns, mice were subjected to various psychosocial stressors (social isolation, intermittent high-fat-diet, or physical restraint) prior to timed observations in a feeding arena that incorporated multiple bait loci. In addition, in vivo microdialysis was used to assess the effects of stressors on the reward system by measuring dopamine levels in the nucleus accumbens (NAcc) shell. Impaired feeding behavior patterns characterized by significant deviations in bait selection (i.e. fixated feeding) and prolonged periods of eating (i.e. protracted feeding) were observed in stressed mice relative to non-stressed controls. In addition to clear behavioral effects, the stressors also negatively impacted dopamine levels at the nucleus accumbens shell. Normalization of dopamine reversed the fixated feeding behavior, whereas specifically inhibiting neuronal activity in the dopaminergic neurons of the ventral tegmental area that project to the nucleus accumbens shell caused similar impairments in feeding. Given that the deviations were not consistently accompanied by changes in the amount of bait consumed, body weight, or metabolic factors, the qualitative effects of psychosocial stressors on feeding behavior likely reflect perturbations to a critical pathway in the mesolimbic dopamine system. These findings provide compelling evidence that aberrations in feeding behavior patterns can be developed as sensitive biomarkers of psychosocial stress and possibly a prodromal state of neuropsychiatric diseases. Significance StatementFeeding behavior can be affected by neuropsychiatric disorders including psychosocial stressors, and the evaluation of eating behavior was mainly based on food intake. However, it is speculated that not only food intake but also feeding behavior patterns can be affected in such disorders. The biological processes underlying the feeding behavior patterns have not been clarified yet. We found that aberrant feeding behaviors in mice characterized by fixated feeding were provoked by psychosocial stressors. The qualitative effects of psychosocial stressors on feeding behavior reflect perturbations in the mesolimbic dopamine system. These findings provide compelling evidence that aberrations in feeding behavior patterns can be developed as sensitive biomarkers of psychosocial stress and possibly a prodromal state of neuropsychiatric diseases.

neuroscience↗

bioRxiv2021

Chemical induction of gut β-like-cells by combined FoxO1/Notch inhibition as a glucose-lowering treatment for diabetes

Lifelong insulin replacement remains the mainstay of type 1 diabetes treatment. Genetic FoxO1 ablation promotes enteroendocrine cell (EECs) conversion into glucose-responsive {beta}-like cells. Here, we tested whether chemical FoxO1 inhibitors can generate {beta}-like gut cells. Pan-intestinal epithelial FoxO1 ablation expanded the EEC pool, induced {beta}-like cells, and improved glucose tolerance in Ins2Akita/+ mice. This genetic effect was phenocopied by small molecule FoxO1 inhibitor, Cpd10. Cpd10 induced {beta}-like cells that released insulin in response to glucose in mouse gut organoids, and this effect was strengthened by the Notch inhibitor, DBZ. In Ins2Akita/+ mice, a five-day course of either Cpd10 or DBZ induced insulin-immunoreactive {beta}-like cells in the gut, lowered glycemia, and increased plasma insulin levels without apparent adverse effects. These results provide proof of principle of gut cell conversion into {beta}-like cells by a small molecule FoxO1 inhibitor, paving the way for clinical applications. One Sentence SummaryOrally available small molecule FoxO1 inhibitor phenocopied genetic FoxO1 ablation in generating gut {beta}-like cells

developmental biology↗

bioRxiv2021

Vibrio cholerae El Tor strains linked to global cholera are homogeneous by pulsed-field gel electrophoresis

Vibrio cholerae O1 El Tor, causative agent of the ongoing seventh cholera pandemic, is native to the aquatic environment of the Ganges Delta, Bay of Bengal (GDBB). Recent studies traced pandemic strains to the GDBB and proposed global spread of cholera had occurred via intercontinental transmission. In the research presented here, NotI-digested genomic DNA extracted from V. cholerae O1 clinical and environmental strains isolated in Bangladesh during 2004 - 2014 was analyzed by pulsed-field gel electrophoresis (PFGE). Results of cluster analysis showed 94.67% of the V. cholerae isolates belonged to clade A and included the majority of clinical isolates of spatio-temporal origin and representing different cholera endemic foci. The rest of the strains were estuarine, all environmental isolates from Mathbaria, Bangladesh, and occurred as singletons, clustered in clades B and C, or in the small clades D and E. Cluster analysis of the Bangladeshi strains and including 157 El Tor strains from thirteen countries in Asia, Africa, and the Americas revealed 85% of the total set of isolates belonged to clade A, indicating all were related, yet did not form an homogeneous cluster. Overall, 15% of the global strains comprised multiple small clades or segregated as singletons. Three sub-clades could be discerned within the major clade A, reflecting distinct lineages of V. cholerae El Tor associated with cholera in Asia, Africa, and the Americas. The presence in Asia and the Americas of non-pandemic V. cholerae El Tor populations differing by PFGE and from strains associated with cholera globally suggests different ecotypes are resident in distant geographies. Author SummaryCholera is a major health threat, especially in the Ganges Delta, Bay of Bengal (GDBB). Vibrio cholerae, causative agent of cholera, is native to the GDBB aquatic environment. Recent genomic studies suggest GDBB is the cholera hotspot where the disease spreads globally via human activity. Pulsed-field gel electrophoresis (PFGE) of NotI-digested genomic DNA from V. cholerae El Tor endemic cholera strains was done, including Bangladesh aquatic environment and clinical strains from distant geographical regions representing three cholera-prone continents. Results showed the majority of pandemic strains belonged to a major cluster, suggesting clonal relatedness. Ecotypes were detected, indicating geographically specific lineages. It is concluded that epidemic strains in Bangladesh and thirteen countries of Asia, Africa, and the Americas are geographically adapted, with independent evolution of the bacterium in respective geographical regions.

molecular biology↗

bioRxiv2021

Predictive regulation of cardiovascular system on emergence of auditory-motor interaction in young infants

Humans develop auditory-motor interaction to produce a variety of rhythmic sounds using body movements, which are often produced and amplified with tools, such as drumming. The extended production of sounds allows us to express a wide range of emotions, accompanied by physiological changes. According to previous studies, even young infants enhance movements in response to auditory feedback. However, their exhibition of physiological adaptation on emergence of auditory-motor interaction is unclear. We investigated the movement and cardiac changes associated with auditory feedback to spontaneous limb movements in 3-month-old infants. The results showed that infants increased the frequency of limb movements inducing auditory feedback, while they exhibited the more regular rhythm of the limb movements. Furthermore, heart rate increase associated with the limb movement was first inhibited immediately after the timing of the auditory feedback, which may reflect sustained attention to the auditory stimuli. Then, through auditory-motor experience, the heart rate increase was inhibited even prior to the auditory feedback, leading to suppression on the peak intensity of the heart rate increase. These findings suggest that young infants regulate the cardiovascular system as well as limb movements in anticipation of the auditory feedback. The anticipatory regulation associated with movement and attentional changes may contribute to reduced cardiovascular stress in auditory-motor interaction, and provide a developmental basis for more sophisticated goal-directed behavior of producing rhythmic sounds.

neuroscience↗

bioRxiv2021

m6A demethylase ALKBH5 promotes tumor cell proliferation by destabilizing IGF2BPs target genes and worsens the prognosis of patients with non-small cell lung cancer

The modification of N6-methyladenosine (m6A) in RNA and its eraser ALKBH5, an m6A demethylase, play important roles across various steps of human carcinogenesis. However, the involvement of ALKBH5 in non-small cell lung cancer (NSCLC) development remains to be completely elucidated. The current study revealed that the expression of ALKBH5 were increased in NSCLC and increased expression of ALKBH5 worsened the prognosis of patients with NSCLC. In vitro study revealed that ALKBH5 knockdown suppressed cell proliferation ability of PC9 and A549 cells as well as promoted G1 arrest and increased the number of apoptotic cells. Furthermore, ALKBH5 overexpression increased the cell proliferation ability of the immortalized cell lines. Microarray analysis and western blotting revealed that the expression of CDKN1A or TIMP3 were increased by ALKBH5 knockdown. These alterations were offset by a double knockdown of both ALKBH5 and one of the IGF2BPs. The decline of mRNAs was, at least partly, owing to the destabilization of these mRNAs by one of the IGF2BPs. In conclusions, the ALKBH5-IGF2BPs axis promotes cell proliferation and tumorigenicity, which in turn causes the unfavorable prognosis of NSCLC.

cancer biology↗

bioRxiv2021

Inhibition of N-myristoyltransferase Promotes Naive Pluripotency in Mouse and Human Pluripotent Stem Cells

Naive and primed states are distinct states of pluripotency during early embryonic development that can be captured and converted to each other in vitro. To elucidate the regulatory mechanism of pluripotency, we performed a recessive genetic screen of homozygous mutant mouse embryonic stem cells (mESCs) and found that suppression of N-myristoyltransferase (Nmt) promotes naive pluripotency. Disruption of Nmt1 in mESCs conferred resistance to differentiation. Suppression of Nmt in mouse epiblast stem cells (mEpiSCs) promoted the conversion from the primed to the naive state. This effect was independent of Src, which is a major substrate of Nmt and is known to promote differentiation of mESCs. Suppression of Nmt in naive-state human induced pluripotent stem cells (hiPSCs) increased the expression of the naive-state marker. These results indicate that Nmt is a novel target for the regulation of naive pluripotency conserved between mice and humans.

developmental biology↗

bioRxiv2021

Desiccation-induced fibrous condensation of CAHS protein from an anhydrobiotic tardigrade

Anhydrobiosis is one of the most extensively studied forms of cryptobiosis that is induced in certain organisms as a response to desiccation. Anhydrobiotic species has been hypothesized to produce substances that can protect their biological components and/or cell membranes without water. In extremotolerant tardigrades, highly hydrophilic and heat-soluble protein families, cytosolic abundant heat-soluble (CAHS) proteins, have been identified, which are postulated to be integral parts of the tardigrades response to desiccation. However, the molecular mechanisms underlying these protein functions remain to be fully elucidated. In this study, we perfomed in vitro and in vivo characterizations of the self-assembling property of CAHS1 protein, a major isoform of CAHS proteins from Ramazzottius varieornatus, using a series of spectroscopic and microscopic techniques. Our in vitro observations showed that CAHS1 proteins homo-oligomerized via the C-terminal -helical region and formed a hydrogel as their concentration increased, and that these molecular assembling processes were reversible. Furthermore, our in vivo observations demonstrated that the overexpressed CAHS1 proteins formed condensates under desiccation-mimicking conditions. These data strongly suggested that, upon drying, the CAHS1 proteins form oligomers and eventually underwent sol-gel transition in tardigrade cytosols. Thus, it is proposed that the CAHS1 proteins form the cytosolic fibrous condensates, which presumably have variable mechanisms for the desiccation tolerance of tardigrades. These findings provide insights into the protective mechanisms involved in the anhydrobiosis of tardigrades.

biochemistry↗

bioRxiv2020

CLOCK/BMAL1 interferes with segmentation clock oscillation in mouse embryonic organoids

In mammals, circadian clocks are strictly suppressed during early embryonic stages as well as pluripotent stem cells, by the lack of CLOCK/BMAL1 mediated circadian feedback loops. During ontogenesis, the innate circadian clocks emerge gradually at a late developmental stage, then, with which the circadian temporal order is invested in each cell level throughout a body. Meanwhile, in the early developmental stage, a segmented body plan is essential for an intact developmental process and somitogenesis is controlled by another cell-autonomous oscillator, the segmentation clock, in the posterior presomitic mesoderm (PSM). In the present study, focusing upon the interaction between circadian key components and the segmentation clock, we investigated the effect of the CLOCK/BMAL1 on the segmentation clock Hes7 oscillation, revealing that the expression of functional CLOCK/BMAL1 severely interferes with the ultradian rhythm of segmentation clock in induced PSM and gastruloids. RNA sequencing analysis showed that the premature expression of CLOCK/BMAL1 affects the Hes7 transcription and its regulatory pathways. These results suggest that the suppression of CLOCK/BMAL1-mediated transcriptional regulation during the somitogenesis may be inevitable for intact mammalian development.

developmental biology↗

bioRxiv2020

Key Nucleation Stages and Associated Molecular Determinants and Processes in pH-Induced Formation of Amyloid Beta Oligomers as Revealed by High-Speed AFM

Non-fibrillar oligomers formed via nucleation from amyloid beta (AB) peptides are currently implicated in the neurotoxicity of Alzheimers disease. Thus, shedding light on the molecular mechanisms underlying their formation is important for identifying targets for drug therapies. This is however an enduring challenge due to the inability to detect AB nucleation processes in the lag phase from bulk kinetic assays, while time-course analyses using a series of peptide solutions involve the discontinuous observation of dynamic nucleation processes and pathways. In this study, by adjusting the pH of AB42 peptide samples while simultaneously imaging with high-speed atomic force microscopy (HS-AFM), we show the in-situ, continuous visualization of dynamic AB42 nucleation at the molecular level. The process reveals a pH-induced saturation regime, enabling a critical monomer substrate concentration to initiate the birth of nucleation. A number of key nucleation phases are identified, including pre-nucleation, saturation regime (mass surface adsorption), nucleation and post-nucleation growth, eventually leading to the formation of predominately oligomer species. HS-AFM observations further reveal the distinct, molecular processes associated with each nucleation phase that constitute the path-dependent formation of different AB species, namely an intial monomer "diffuse-like" surface layer, followed by the emergence of nuclei and then subsequent formation and growth of new complexes and oligomers. In particular, the ability of individual nuclei to undergo surface diffusion and establish new complexes via binding interactions with other species encountered in the system was found to be a significant mechanism influencing the growth of oligomers. Herein, the study contributes to current AB nucleation theories by ascribing new molecular mechanisms. More generally, the knowledge gained from single molecule techniques can greatly assist in our current understanding of various biological processes of AB peptide such as nucleation, growth, aggregation and their related kinetic pathways.

neuroscience↗

bioRxiv2020

Endocrine signaling mediates asymmetric motor deficits after unilateral brain injury

A paradigm in neurology is that brain injury-induced motor deficits (e.g. hemiparesis and hemiplegia) arise due to aberrant activity of descending neural pathways. We discovered that a unilateral injury of the hindlimb sensorimotor cortex of rats with completely transected thoracic spinal cord produces hindlimb postural asymmetry with contralateral flexion, and asymmetric changes in nociceptive hindlimb withdrawal reflexes and gene expression patterns in lumbar spinal cord. The injury-induced postural effects were abolished by prior hypophysectomy and were mimicked by transfusion of serum from animals with unilateral brain injury. Antagonists of the opioid and vasopressin receptors blocked formation of hindlimb postural asymmetry suggesting that these neurohormones mediate effects of brain injury on lateralized motor responses. Our data indicate that descending neural control of spinal circuits is complemented by a previously unknown humoral signaling from injured brain to the contra- and ipsilesional hindlimbs, and suggest the existence of a body side-specific neuroendocrine regulation in bilaterally symmetric animals.

neuroscience↗

bioRxiv2019

Forelimb movements evoked by optogenetic stimulation of the macaque motor cortex

Optogenetics has become an indispensable tool for investigating brain functions. Although non-human primates are particularly useful models for understanding the functions and dysfunctions of the human brain, application of optogenetics to non-human primates is still limited. In the present study, we generated an effective adeno-associated viral vector serotype DJ to express channelrhodopsin-2 (ChR2) under the control of a strong ubiquitous CAG promoter and injected into the somatotopically identified forelimb region of the primary motor cortex in macaque monkeys. ChR2 was strongly expressed around the injection sites, and optogenetic intracortical microstimulation (oICMS) through a homemade optrode induced prominent cortical activity: Even single-pulse, short duration oICMS evoked long-lasting repetitive firings of cortical neurons. In addition, oICMS elicited distinct forelimb movements and muscle activity, which were comparable to those elicited by conventional electrical ICMS. The present study removed obstacles to optogenetic manipulation of neuronal activity and behaviors in non-human primates.

neuroscience↗

bioRxiv2019

Integrative genomic and epigenomic analyses identify a distinct role of c-Myc and L-Myc for lineage determination in small cell lung cancer

Comprehensive genomic analyses of small cell lung cancer (SCLC), the most aggressive form of lung cancer, have revealed near universal loss of tumor suppressors (RB1 and TP53) and frequent genomic amplification of all three MYC family members. The amplification of each Myc family member is mutually exclusive; hence it had been long suggested that they are functionally equivalent. However, their expression has more recently been associated with specific neuroendocrine markers and distinct histopathology. In this study, we explored a novel role of c-Myc and L-Myc as lineage determining factors contributing to SCLC molecular subtypes and histology. Integrated analyses of a gene regulatory network generated from mRNA expression of primary SCLC tumor and chromatin state profiling of SCLC cell lines showed that Myc family members impart distinct transcriptional programs associated with lineage state; wherein the L-Myc signature was enriched for neuronal pathways while the c-Myc signature was enriched for Notch signaling and epithelial-to-mesenchymal transition. We investigated the functional redundancy and distinction of c-Myc and L-Myc, and noted the insufficiency of L-Myc to induce lineage switch in contrast to the potential of c-Myc to induce trans-differentiation. c-Myc rewires the Myc-accessible landscape and activates neuron al repressor, Rest to mediate transition from ASCL1-SCLC to NeuroD1-SCLC characterized by distinct LCNEC-like histopathology. Collectively, our findings reveal a previously undescribed role of historically defined general oncogenes, c-Myc and L-Myc, for regulating lineage plasticity across molecular subtypes as well as histological subclasses.

cancer biology↗