Biology subjects

Pan, G.

Publications and source records attributed to Pan, G..

36 records · Page 2Linked to original sources

bioRxiv2023

Enterocytozoon hepatopenaei Proliferate in Procambarus clarkii: A Warning for Crayfish and Shrimp Aquaculture

The pacific whiteleg shrimp (Litopenaeus vannamei) and the crayfish (Procambarus clarkii) are the most productive aquatic animals in the world. The prevalence of the microsporidium Enterocytozoon hepatopenaei (EHP), an intracellular spore-forming unicellular parasite which leading retarded growth of L. vannamei, has caused severe economic losses in most shrimp farming country. In this study, we found that the wild P. clarkii, living in shrimp ponds with EHP outbreak, excreted white faeces after temporary laboratory culture. The hepatopancreas (HP) of symptomatic crayfish exhibited a lighter color and severely atrophied. H&E-stain showed tissue lesions in both hepatopancreas and intestine, and clustered microsporidian spores were filled in the cytoplasm of the cells. PCR using EHPptp2 and two microsporidian-universal primers sets demonstrated the existence of EHP in the hepatopancreas, intestine and the white feces of P. clarkii. The EHP loads of 103-104 copies of EHPptp2/50 ng HPgDNA were detected by qPCR. Developing stages and mature spores of EHP were observed in hepatopancreas of P. clarkii through indirect-immunofluorescence assay (IFA) and transmission electron microscopy (TEM). Considering the large-scale cultivation of L. vannamei and P. clarkii, overlap farming areas between these two species as well as the ability of crayfish to crawl on land and water, our finding indicates the potential role of P. clarkii in the transmission of EHP, and it is an early warning for crayfish and shrimp farming.

microbiology↗

bioRxiv2023

A muscle hypertrophy-derived myokine reprograms the stromal vascular fractions differentiation towards thermogenic adipocytes in subcutaneous adipose tissue

Skeletal muscle plays a significant role in both local and systemic energy metabolism; however, the cross-talk between skeletal muscle and adipose tissue remains largely unexplored. In this study, we identify the HIF2-Bambi-Thbs4 axis as a critical driver of muscle hypertrophy and metabolic improvement. Deletion of Bambi induces muscle hypertrophy and oxidative switching, thereby enhancing local and systemic metabolism under conditions of rodent chow and high-fat diets (HFD). Other than the metabolic regulation of skeletal muscle hypertrophy, we hypothesize that a portion of this improvement may be attributed to the metabolic reprogramming of the stromal vascular fraction (SVFs) of iWAT, promoting the development of beige adipocytes. Leveraging multi-omics approaches, we establish Thbs4 as a newly identified, muscle hypertrophy-derived myokine that serves as an essential regulator of this metabolic reprogramming. Thbs4 is upregulated in skeletal muscle during hypertrophy and aerobic exercise, localizes to the iWAT membrane, and facilitates the transformation of white adipocytes into beige adipocytes under conditions such as cold exposure, muscle hypertrophy, or aerobic exercise. Moreover, overexpression of Thbs4 elevates its plasma levels and leads to the transformation of white to beige adipocytes, therefore offering long-term protection against HFD-induced metabolic disorders. Conversely, Thbs4 knockout (Thbs4-KO) disrupts the metabolic reprogramming of SVFs and exacerbates metabolic syndromes induced by an HFD, mirroring the observed decline in Thbs4 levels in aged mice. Therefore, our findings underscore Thbs4s potential as both a long-term metabolic protective factor and a therapeutic target for the treatment of metabolic disorders. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=197 HEIGHT=200 SRC="FIGDIR/small/558627v1_ufig1.gif" ALT="Figure 1"> View larger version (63K): org.highwire.dtl.DTLVardef@1178e6org.highwire.dtl.DTLVardef@1184d4eorg.highwire.dtl.DTLVardef@7b592aorg.highwire.dtl.DTLVardef@1b0b03_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIBambi, a direct target gene of HIF2 in skeletal muscle, when deleted, triggers muscle hypertrophy and the transformation of white into beige adipocytes, improving systemic energy metabolism. C_LIO_LIThe metabolic reprogramming of stromal vascular fractions (SVFs) contributes to the observed improvements in energy metabolism and adipocyte hyperplasia. C_LIO_LIThbs4, a novel myokine produced in skeletal muscle during hypertrophy and aerobic exercise, plays a key role in the transformation of white into beige adipocytes. C_LIO_LIOverexpression of Thbs4 provides enduring protection against high-fat diet (HFD)-induced metabolic disorders, demonstrating its potential as a therapeutic target. C_LIO_LIThbs4 deletion abrogates the beneficial metabolic reprogramming of SVFs and exacerbates HFD-induced metabolic syndromes, further underlining its crucial role in metabolic regulation. C_LI

physiology↗

bioRxiv2023

Microsporidia Ser/Thr Protein Phosphatase PP1 Targets DCs MAPK Pathway and Impair Immune Functions

Microsporidia are difficult to completely eliminate. Their persistence may disrupt host cell functions. Here in this study, we aimed to elucidate the impairing effects and consequences of microsporidia infection upon dendritic cells (DCs). We used the zoonotic microsporidia species, Enterocytozoon hellem, in our studies. In vivo experiments showed that E. hellem-infected mice were more susceptible to further pathogenic challenges. DCs were identified as the most affected group of cells. In vitro assays revealed that E. hellem infection impaired the immune functions of DCs as reflected by down-regulation of cytokine expression, lower extent of maturation and antigen presentation. E. hellem infection decreased the ability of DCs to prime and stimulate T cells, thereby hampering host immune cell functions. We further demonstrate that E. hellem Ser/Thr protein phosphatase PP1 directly interacts with host p38(MAPK14) to manipulate the p38 (MAPK14)/NFAT-5 axis of the MAPK pathway. Our study is the first to elucidate the molecular mechanisms of the impairing effects of microsporidia on host DCs immune functions. The emerging of microsporidiosis may be great threat to public health. HighlightsO_LIPersistence of Microsporidia within host impairs dendritic cell functions such as phagocytosis, maturation, antigen presentation and T cell priming, thereby disrupting both innate and adaptive immunities and making the host more vulnerable to secondary infections C_LIO_LIMicrosporidia impairs DCs function via Serine/Threonine Protein Phosphatase PP1 directly targeting DCs p38/MAPK pathway C_LIO_LILatent Microsporidia infection and persistence is a great threat to public health when assessing acute and emerging pathogen risk C_LI

microbiology↗

bioRxiv2023

Screening of the Pandemic Response Box identifies anti-microsporidia compounds

Microsporidia are fungi obligate intracellular pathogens, which infect most animals and cause microsporidiosis. Despite the serious threat that microsporidia pose to humans and agricultural animals, few drugs are available for the treatment and control of microsporidia. To identify novel inhibitors, we took advantage of the model organism Caenorhabditis elegans infected with its natural microsporidian Nematocida parisii. We used this system to screen the Pandemic Response Box, a collection of 400 diverse compounds with known antimicrobial activity. After testing these compounds in a 96-well format at high (100 M) and low (40 M) concentrations, we identified four inhibitors that restored the ability of C. elegans to produce progeny in the presence of N. parisii. All four compounds reduced the pathogen load of both N. parisii and Pancytospora epiphaga, a C. elegans-infecting microsporidia related to human-infecting species. One of these compounds, a known inhibitor of a viral protease, MMV1006203, inhibited invasion and prevented the firing of spores. A bis-indole derivative, MMV1593539, decreased spore viability. An albendazole analog, MMV1782387, inhibited proliferation of N. parisii. We tested albendazole as well as 5 other analogs and observed that MMV1782387 was amongst the strongest inhibitors of N. parisii and displayed the least host toxicity. Our study further demonstrates the effectiveness of the C. elegans-N. parisii system for discovering microsporidia inhibitors and the compounds we identified provide potential scaffolds for anti-microsporidia drug development.

microbiology↗

bioRxiv2023

Microsporidia dressing up: the spore polaroplast transport through the polar tube and transformation into the sporoplasm membrane

Microsporidia are obligate intracellular parasites that infect a wide variety of hosts, including humans. Microsporidian spores possess a unique, highly specialized invasion apparatus involving the polar filament, polaroplast and posterior vacuole. During spore germination, the polar filament is discharged out of the spore forming the hollow polar tube that transports the sporoplasm components including nucleus into the host cell to achieve the invasion. Due to the complicated topological changes occurring in this process, the formation of sporoplasm is unclear. Here, electron microscopy observation and DiI staining confirmed that during spore germination, a large number of vesicles derived from the polaroplast, nucleus and other cytoplasm were transported out via the polar tube. Meanwhile, the posterior vacuole and plasma membrane remained in the empty spore coat. In addition, there was no DiI-labeled membrane around the nucleus in mature spores, whereas a DiI-labeled limit membrane wrapping nucleus was found at the tip of the extruded polar tube, suggesting that the membrane of sporoplasm was formed outside the mature spore. Two Nosema bombycis sporoplasm surface proteins (NbTMP1 and NoboABCG1.1) were located at the polaroplast in mature spores, in the extruded polar tube and on the sporoplasm membrane, which indicated that the polaroplast transported via the polar tube finally became the limiting membrane of the sporoplasm. Golgi-tracker green and Golgi marker protein syntaxin 6 were also found the same model, which was consistent with the transported polaroplast derived from Golgi transformed into the novel sporoplasm membrane during spore germination. ImportanceMicrosporidia, obligate intracellular pathogenic organisms, cause huge economic losses in agriculture and even threaten human health. The key to successful infection of microsporidia is its unique invasion apparatus which includes the polar filament, polaroplast and posterior vacuole. When the spore is activated to geminate, the polar filament uncoils and undergoes a rapid transition into the hollow polar tube that will transport the sporoplasm components including nucleus into a host cell to achieve the invasion. Knowledge of structure difference between polar filament and polar tube, the process of cargo transport in extruded polar tube, and the formation of the sporoplasm membrane are still poorly understood. Herein, we verify that the polar filament evaginates to form the polar tube, which serves as a conduit for transporting elongated nucleus and other sporoplasm components. And we confirm that the transported polaroplast finally transforms into the novel sporoplasm membrane during spore germination. Our study provides new insights into the cargo transportation process of polar tube and origin of the sporoplasm membrane, which serve as foundations for clarifying the microsporidian infection mechanism.

pathology↗

bioRxiv2023

The maize PLASTID TERMINAL OXIDASE (PTOX) gene controls the carotenoid content of kernels.

O_LICarotenoids perform a broad range of important functions in humans; therefore, carotenoid biofortification of maize (Zea mays L.), one of the most highly produced cereal crops worldwide, would have a global impact on human health. C_LIO_LIPLASTID TERMINAL OXIDASE (PTOX) genes play an important role in carotenoid metabolism; however, the possible function of PTOX in carotenoid biosynthesis in maize has not yet been explored. In this study, we identified the maize PTOX gene ZmPTOX1 by forward genetic screening. C_LIO_LIWhile most higher plant species possess a single copy of the PTOX gene, maize carries two tandemly duplicated copies of ZmPTOX. Characterization of Zmptox1 mutants revealed that disrupting one copy of ZmPTOX1 was enough to impair carotenoid biosynthesis, indicating that ZmPTOX1 is essential for carotenoid biosynthesis in maize kernels. Remarkably, overexpression of ZmPTOX1 significantly improved the content of carotenoids, especially {beta}-carotene (provitamin A), which was increased by ~3-fold, in maize kernels. C_LIO_LIOverall, our study shows that ZmPTOX1 plays a crucial role in carotenoid biosynthesis in maize kernels and suggests that fine-tuning the expression of this gene could improve the nutritional value of cereal grains. C_LI

plant biology↗

bioRxiv2022

Multimodal electrocorticogram active electrode array based on zinc oxide-thin film transistors

Active electrocorticogram (ECoG) electrodes can amplify the weak electrophysiological signals and improve the anti-interference ability, but the traditional active electrodes are so opaque that cannot realize photoelectric collaborative observation. Here an active and fully-transparent ECoG array based on zinc oxide-thin film transistors (ZnO-TFTs) was developed as the local neural signal amplifier for electrophysiological monitoring. The transparency of the proposed ECoG array was up to 85% which is superior to previous reported active electrode array. Various electrical characterizations demonstrated its ability of electrophysiological signal recording, with a higher signal-to-noise ratio of 19.9 dB compared to the Au grid one (13.2 dB). The high transparency of ZnO-TFT electrode array allowed the collecting electrophysiological signals under direct light stimulation on optogenetic mice brain concurrently. The ECoG array could also work under 7-Tesla magnetic resonance imaging to record local brain signal without affecting brain tissue imaging. As the most transparent active ECoG array to date, it provides a powerful multimodal tool for brain observation, including recording brain activity under synchronized optical modulation and 7-Tesla magnetic resonance imaging.

bioengineering↗

bioRxiv2022

Generating Functional Cells Through Enhanced Interspecies Chimerism with Human Pluripotent Stem Cells

Obtaining functional human cells through interspecies chimerism with human pluripotent stem cells (hPSCs) remains unsuccessful due to its extreamly low efficiency. Here, we show that hPSCs failed to differentiate and contribute teratoma in presence of mouse PSCs (mPSCs). While, MYCN, a pro-growth factor dramatically promotes hPSC contribution in teratoma co-formation by hPSCs/mPSCs. MYCN combined with BCL2 (M/B) greatly enhanced conventional hPSCs to integrate into preimplantation embryos of different species, such as mice, rabbits and pigs and substrantially contributed to mouse post-implantation chimera in embryonic and extra-embyonic tissues. Strikingly, M/B-hPSCs injected into preimplantation Flk-1+/- mouse embryos show further enhanced chimerism that allows obtaining live human CD34+ blood progenitor cells from chimeras through cell sorting. The chimera derived human CD34+ cells further gave rise to various subtype blood cells in typical colony forming unit(CFU) assay. Thus, we proof the concept to obtain functional human cells through enchanced interspecies chimerism with hPSCs.

cell biology↗

bioRxiv2021

A lineage-specific epigenetic memory of inflammation potentiates Kras-driven pancreatic tumorigenesis

Inflammation is essential to the disruption of tissue homeostasis, and, in the pancreas, can destabilize the identity of terminally differentiated acinar cells. Herein we employ lineage-traced mouse models to delineate the chromatin dynamics that accompany the cycle of metaplasia and regeneration following pancreatitis, and unveil the presence of an epigenetic memory of inflammation in the pancreatic acinar cell compartment. We observe that despite histologic resolution of pancreatitis, acinar cells fail to return to their molecular baseline after several months, representing an incomplete cell fate decision. In vivo, this epigenetic memory controls lineage plasticity, with diminished metaplasia in response to a second inflammatory insult but increased tumorigenesis with an oncogenic Kras mutation. We demonstrate that both persistent chromatin and transcriptional changes constituting memory are recalled with oncogenic stress. Together, our findings define the dynamics and recall of an epigenetic memory of inflammation that impacts cell fate decisions in a context-dependent manner.

cancer biology↗

bioRxiv2021

Organ-specific metabolic pathways distinguish prediabetes, type 2 diabetes and normal tissues

Defects in pancreatic islets and the progression of multi-tissue insulin resistance in combination with environmental factors are the main causes of type 2 diabetes (T2D). Mass spectrometry-based proteomics of five key-metabolic tissues on a cohort of 42 multi-organ donors provided deep coverage of the proteomes of pancreatic islets, visceral adipose tissue (VAT), liver, skeletal muscle and serum. Enrichment analysis of gene ontology (GO) terms built a tissue-specific map of the chronological order of altered biological processes across healthy controls (CTRL), pre-diabetes (PD) and T2D subjects. This unique dataset allowed us to explore alterations of entire biological pathways and individual proteins in multiple tissues. We confirmed the significant decrease of the citric acid cycle and the respiratory electron transport in VAT and muscle of T2D and we provided a thorough visual representation of the complete set of downregulated proteins. Importantly, we found widespread novel alterations in relevant biological pathways including the increase in hemostasis in pancreatic islets of PD, the increase in the complement cascade in liver and pancreatic islets of PD and the elevation in cholesterol biosynthesis in liver of T2D. Overall, our findings suggest inflammatory, immune and vascular impairments in pancreatic islets as potentially causal factors of insufficient insulin production and increased glucagon levels in the early stages of T2D. In contrast alterations in lipid metabolism and mitochondrial function in the liver and VAT/muscle, respectively, became evident later in manifest T2D. This first multi-tissue proteomic map indicates the temporal order of tissue-specific metabolic dysregulation in T2D development.

cell biology↗

bioRxiv2021

Genome assembly of the maize inbred line A188 provides a new reference genome for functional genomics

Heretofore, little is known about the mechanism underlying the genotype-dependence of embryonic callus (EC) induction, which has severely inhibited the development of maize genetic engineering. Here, we report the genome sequence and annotation of a maize inbred line with high EC induction ratio, A188, which is assembled from single-molecule sequencing and optical genome mapping. We assembled a 2,210 Mb genome with a scaffold N50 size of 11.61 million bases (Mb), compared to those of 9.73 Mb for B73 and 10.2 Mb for Mo17. Comparative analysis revealed that [~]30% of the predicted A188 genes had large structural variations to B73, Mo17 and W22 genomes, which caused considerable protein divergence and might lead to phenotypic variations between the four inbred lines. Combining our new A188 genome, previously reported QTLs and RNA sequencing data, we reveal 8 large structural variation genes and 4 differentially expressed genes playing potential roles in EC induction. HighlightOur manuscript presents a high-quality reference genome of the inbred line A188, and provides new insights into candidate genes underlying maize embryonic callus induction and other maize agronomic traits.

genetics↗

bioRxiv2020

Transferrin receptor (Tfr1) ablation in satellite cells impacts skeletal muscle regeneration through the activation of ferroptosis

Satellite cells (SCs) are critical to the postnatal development and skeletal muscle regeneration. Inactivation of SCs is linked with the skeletal muscle loss. Leveraging on the RNAseq screening, transferrin receptor (Tfr1) is identified to be associated with muscle/SC ageing and the declined regeneration potential. Muscle-specific deletion of Tfr1 results in the growth retardation, metabolic disorder and lethality, shedding light on the importance of Tfr1 in skeletal muscle physiology. Here, our investigation reported that conditional SC-ablation of Tfr1 leads to the SCs inactivation and skeletal muscle regeneration defects, followed by the labile iron accumulation, de novo lipogenesis via fibroadipogenic progenitors (FAPs) and Gpx4/Nrf2-mediated ROS-scavenger defects. These abnormal phenomena, such as Hmox1-mediated myoglobin degradation, Tfr1-Slc39a14 functional switch and the activation of unsaturated fatty acid biosynthesis pathway are orchestrated with the occurrence of ferroptosis in skeletal muscle. Ferroptosis may further prevent SC proliferation and skeletal muscle regeneration. Ferrostatin-1, a ferroptosis inhibitor could not rescue Tfr1-ablation induced ferroptosis. However, intramuscular administration of lentivirus expressing Tfr1 could partially reduce labile iron accumulation, decrease de novo lipogenesis and promote skeletal muscle regeneration. Most importantly, Tfr1/Slc39a14 functional switch, labile iron accumulation and fatty acid biosynthesis are recapitulated in aged skeletal muscle of rodents, indicating that ferroptosis occurs in the skeletal muscles of aged rodents. The present study also bridges the gap between pathogenesis of iron and functional defects in the skeletal muscle, providing mechanistic information to develop anti-aging strategies. One Sentence SummaryConditional ablation of Tfr1 in satellite cells (SCs) results in the SC inactivation, skeletal muscle regeneration defects, labile iron accumulation, and unsaturated fatty acid biosynthesis, leading to the activation of ferroptosis, which is recapitulated in skeletal muscles of aged rodents to be a new cell death form identified in skeletal muscle and sheds light on the development of novel anti-ageing strategies.

cell biology↗

bioRxiv2020

Robust range of auditory periphery development, eye opening, and brain gene expression in Wistar rat pups that experience variation in maternal backgrounds

The experience of variation in maternal licking and grooming (LG) is considered a critical influence in neurodevelopment related to stress and cognition, but little is known about its relationship to early sensory development. In this study, we used a maternal selection approach to test the hypothesis that differences in LG during the first week of life influence the timing of hearing onset in Wistar rat pups. We performed a range of tests, including auditory brainstem responses (ABR), tracking of eye opening (EO), micro-CT X-ray tomography, and qRT-PCR to monitor neurodevelopmental changes in the female and male progeny of low-LG and high-LG dams. Our results show that variation in maternal LG is not overtly associated with different timing of ABR onset and EO in the progeny. However, the data provide insight on the delay between hearing onset and EO, on key functional and structural properties that define hearing onset at the auditory periphery, and on changes in brain gene expression that include the first evidence that: a) the hypoxia-sensitive pathway is regulated in subcortical and cortical auditory brain regions before hearing onset, and b) implicates maternal LG in regulation of Bdnf signaling in auditory cortex after hearing onset. Altogether, these findings provide a baseline to evaluate how factors that severely disrupt the early maternal environment may affect the expression of robust developmental sensory programs. SIGNIFICANCE STATEMENTEarly life experience during sensitive developmental periods can induce long-term effects on the neurobiological development of the offspring. In the present work we tested the hypothesis that variation in maternal licking and grooming (LG) affects the timing of hearing onset in Wistar rat pups. To our surprise the results did not support the hypothesis. Instead, we found a robust range of early and late auditory development that was independent of maternal LG. Nevertheless, the study provides new findings on the delay between hearing onset and eye opening, on key functional and structural properties that define hearing onset at the auditory periphery, and the first evidence that a) the hypoxia-sensitive pathway is regulated in the central auditory system during the sensitive period before hearing onset, and b) maternal LG is implicated in regulation of Bdnf signaling during the sensitive period after hearing onset. These findings provide a baseline to evaluate how factors that severely disrupt the early maternal environment may affect the expression of robust developmental sensory programs.

neuroscience↗

bioRxiv2020

Dscam gene triplication causes neocortical overinhibition in Down syndrome

A growing number of molecules have been identified as regulators of inhibitory synapse development, but whether dysregulated expression of these molecules contribute to brain disorders is poorly understood. Here we show that Down syndrome cell adhesion molecule (Dscam) regulates the inhibition of neocortical pyramidal neurons (PyNs) in a level-dependent fashion. Loss of Dscam impairs inhibitory neuron development and function. In the Ts65Dn mouse model for Down syndrome, where Dscam is overexpressed, GABAergic innervation of cortical PyNs by chandelier and basket cells is increased. Genetic normalization of Dscam expression rescues the excessive GABAergic innervation and the increased inhibition of PyNs. These findings demonstrate excessive GABAergic innervation and inhibition in the neocortex of Down syndrome mouse model and identify Dscam overexpression as the cause. They also implicate dysregulated Dscam levels as a potential pathogenic driver in related neurological disorders.

neuroscience↗

bioRxiv2019

Frameshift mutations of YPEL3 alter the sensory circuit function in Drosophila

A frameshift mutation in Yippee-like (YPEL) 3 was recently found from a rare human disorder with peripheral neurological conditions including hypotonia and areflexia. The YPEL gene family is highly conserved from yeast to human, but their functions are poorly defined. Moreover, the pathogenicity of the human YPEL3 variant is completely unknown. To tackle these issues, we generated a Drosophila model of human YPEL3 variant by CRISPR-mediated In-del mutagenesis. Gene-trap analysis suggests that Drosophila YPEL3 (dYPEL3) is predominantly expressed in subsets of neurons, including nociceptors. Analysis on chemical nociception induced by allyl-isothiocyanate (AITC), a natural chemical stimulant, revealed a reduced nociceptive response in dYPEL3 mutants. Subsequent circuit analysis showed a reduction in the activation of second-order neurons (SONs) in the pathway without affecting nociceptor activation upon AITC treatment. Although the gross axonal and dendritic development of nociceptors was not affected, the synaptic contact between nociceptors and SONs were decreased by dYPEL3 mutations. Together, these suggest that the frameshift mutation in human YPEL3 causes neurological conditions by weakening synaptic connection through presynaptic mechanisms.

neuroscience↗

bioRxiv2018

Intra- and inter-individual metabolic profiling highlights carnitine and lysophosphatidylcholine pathways as key molecular defects in type-2 diabetes

Type-2 diabetes (T2D) mellitus is a complex metabolic disease commonly caused by insulin resistance in several tissues. We performed a matched two-dimensional metabolic screening in tissue samples from a cohort of 43 multi-organ donors. The intra-individual analysis was assessed across five key-metabolic tissues (serum, adipose tissue, liver, pancreatic islets and muscle), and the inter-individual across three different groups reflecting T2D progression. We identified 92 metabolites differing significantly between non-diabetes and T2D subjects. Carnitines were significantly higher in liver, while lysophosphatidylcholines significantly lower in muscle and serum. An investigation of the progression to overt T2D showed that deoxycholic acid glycine conjugate was significantly higher in liver of pre-diabetes samples while additional increase in T2D was insignificant. A subset of lysophosphatidylcholines were significantly lower in the muscle of pre-diabetes subjects. Overall, the analysis of this unique dataset can increase the understanding of the metabolic interplay between organs in the development of T2D.

physiology↗

bioRxiv2018

Baculovirus utilizes cholesterol transporter Niemann-Pick C1 for host cell entry

The dual roles of baculovirus for the control of natural insect populations as an insecticide, and for foreign gene expression and delivery, have called for a comprehensive understanding of the molecular mechanisms governing viral infection. Here, we demonstrate that the Bombyx mori Niemann-Pick C1 (BmNPC1) is essential for baculovirus infection in insect cells. Both pretreatment of Bombyx mori embryonic cells (BmE) with NPC1 antagonists (imipramine or U18666A) and down-regulation of NPC1 expression resulted in a significant reduction in baculovirus BmNPV (Bombyx mori nuclear polyhedrosis virus) infectivity. Furthermore, we show that the major glycoprotein gp64 of BmNPV, responsible for both receptor binding and fusion, is able to interact predominantly with the BmNPC1 C domain, with an enhanced binding capacity at low pH conditions, indicating that NPC1 most likely plays a role during viral fusion in endosomal compartments. Our results, combined with previous studies identifying an essential role of hNPC1 in filovirus infection, suggest that the glycoprotein of several enveloped viruses possess a shared strategy of exploiting host NPC1 proteins during virus intracellular entry events.\n\nIMPORTANCEBmNPV is one of the most important members of the Baculoviridae; many viruses in this family have been frequently employed as viral vectors for foreign gene delivery or expression and as biopesticides, but their host receptors still remain unclear. Here, we describe that the intracellular cholesterol transporter BmNPC1 is indispensable for BmNPV infection in insect cells, and it interacts with the major viral glycoprotein gp64. Our study on the role of BmNPC1 in baculovirus infection has further expanded the list of the enveloped viruses that require host NPC1 proteins for entry, and will ultimately help us to uncover the molecular mechanism of the involvement of NPC1 proteins in the entry process of many enveloped viruses.

microbiology↗

bioRxiv2017

Resolution of Reprogramming Transition States by Single Cell RNA-Sequencing

The Yamanaka factors convert mouse embryonic fibroblasts (MEFs) into induced pluripotent stem cells (iPSCs) through a highly heterogeneous process. Here we profile single cells undergoing an optimized 7-day reprogramming process and show that cells start reprogramming relatively in sync, but diverge into two branches around day 2. The first branch of cells expressing Cd34/Fxyd5/Psca become nonpluripotent. The second one contains cells that are first Oct4+, then Dppa5a+ and pluripotent. We show that IFN-{gamma} blocks this late transition. Our results reveal the heterogeneous nature of somatic cell reprogramming, identify Dppa5a as a marker for pluripotent and innate immunity as a potential barrier for reprogramming.\n\nOne Sentence SummarySingle cell RNA sequencing reveals a continuum of cell fates from somatic to pluripotent and Dppa5a as a marker for chimera-competent iPSCs.

cell biology↗