Biology subjects

Ying, W.

Publications and source records attributed to Ying, W..

At least 37 records · Page 2Linked to original sources

bioRxiv2020

Oxidative stress induces cell death partially by decreasing both mRNA and protein levels of nicotinamide phosphoribosyltransferase in PC12 cells

Numerous studies have indicated critical roles of NAD+ deficiency in both aging and multiple major diseases. It is critical to investigate the mechanisms underlying the NAD+ deficiency under the pathological conditions. It has been reported that there was a decreased level of Nicotinamide phosphoribosyltransferase (Nampt) - an important enzyme in the salvage pathway of NAD+ synthesis - under certain pathological conditions, while the mechanisms underlying the Nampt decrease require investigation. In this study we used differentiated PC12 cells as a cellular model to investigate the effects of oxidative stress on both the mRNA and protein levels of Nampt, as well as the role of this effect in oxidative stress-induced cell death: First, Nampt plays significant roles in both the NAD+ synthesis and survival of the cells under basal conditions; second, H2O2 produced significant decreases in both the mRNA levels and the protein levels of Nampt; and third, H2O2 induced cell death partially by producing the decreases in the mRNA and protein levels of Nampt, since the Nampt inhibitor or the Nampt activator significantly exacerbated or attenuated the H2O2-induced cell death, respectively. Collectively, our study has indicated that oxidative stress can decrease both the mRNA and protein levels of Nampt, which has indicated a novel mechanism underlying the NAD+ deficiency in aging and under multiple pathological conditions. Our study has also indicated that the decreased Nampt levels contribute to the H2O2-induced cell death, suggesting a new mechanism underlying oxidative cell death.

cell biology↗

bioRxiv2020

A fast numerical method for oxygen supply in tissue with complex blood vessel network

Oxygen field evaluation is important in modeling and simulation of many important physiological processes of animals, such as angiogenesis. However, numerical simulation of the oxygen field in animal tissue is usually limited by the unusual coupling of different mechanisms, the nonlinearity of the model, and the complex geometry of refined blood vessel networks. In this work, a fast numerical method is designed for the simulation of oxygen supply in tissue with a large-scale complex vessel network. This method employs an implicit finite-difference scheme to compute the oxygen field. By virtue of an oxygen source distribution technique from vessel center lines to mesh points and a corresponding post-processing technique that eliminate the local numerical error induced by source distribution, square mesh with relatively large mesh sizes can be applied while sufficient numerical accuracy is maintained. The new method has computational complexity which is slightly higher than linear with respect to the number of mesh points and has a convergence order which is slightly lower than second order with respect to the mesh size. As an example, the oxygen field of a tissue irrigated by a blood vessel network with more than four thousand blood vessels can be accurately computed within one minute with our new method. The new method will definitely promote further researches based on evaluation of oxygen field, such as modeling of angiogenesis and pathogenesis of many cardiovascular diseases.

physiology↗

bioRxiv2020

A Mild Keratin 1 Decrease Leads to Cell Death and Increased Oxidative Stress in B16-F10 Melanoma Cell Lines

Keratins play multiple significant biological roles in epithelium. K1 / keratin 10 (K10) heterodimer is a hallmarker for keratinocyte differentiation. While keratins are absent in normal melanocyte, keratins have been found in both melanoma cell lines and human melanoma. The biological significance of the keratins in melanoma cells has remained unclear. In our current study we applied K1 siRNA to investigate the biological significance of the K1 in B16-F10 melanoma cells. We found that as low as a 16% decrease in the K1 level led to significant increases in both apoptosis and necrosis of the cells. Moreover, the mild K1 decrease led to significant increases in both dichlorofluorescein (DCF) and ethidium signals - two indicators of oxidative stress - in the cells. Collectively, our findings have provided the first evidence indicating both a critical role of the K1 in maintaining the survival of melanoma cells and an important role of the K1 in modulating the oxidative stress state of the cells. These findings have exposed new functions of keratins in cancer cells, suggesting that K1 may become a novel therapeutic target for melanoma.

cancer biology↗

bioRxiv2020

Adipose tissue macrophages orchestrate β cell adaptation in obesity through secreting miRNA-containing extracellular vesicles

Obesity induces an adaptive expansion of β cell mass and insulin secretion abnormality. Here, we explore a novel role of adipose tissue macrophages (ATMs) in mediating obesity-induced β cell function and proliferation through releasing miRNA-containing extracellular vesicles (EVs). ATM EVs derived from obese mice notably suppress insulin secretion in both in vivo and in vitro experiments, whereas there are more proliferating β cells in the islets treated with obese ATM EVs. Depletion of miRNAs blunts the ability of obese ATM EVs to regulate β cell responses. miR-155, a highly enriched miRNA within obese ATM EVs, exerts profound regulation on β cell functions, as evidenced by impaired insulin secretion and increased β cell proliferation after miR-155 overexpression in β cells. By contrast, knockout of miR-155 can attenuate the regulation of obese ATM EVs on β cell responses. We further demonstrate that the miR-155-Mafb axis plays a critical role in controlling β cell responses. Taken together, these studies show a novel mechanism by which ATM-derived EVs act as endocrine cargoes delivering miRNAs and subsequently mediating β cell adaptation and functional dysfunction in obesity.Competing Interest StatementThe authors have declared no competing interest.View Full Text

physiology↗

bioRxiv2020

Catestatin (CST) is a key mediator of the immunoendocrine regulation of cardiovascular function

Hypertension (HTN) is associated with inflammation and excessive production of catecholamines. Hypertensive patients have reduced plasma levels of Catestatin (CST), a bioactive cleavage product of the prohormone Chromogranin A (CgA). In mouse models, HTN symptoms can be reduced by administration of CST, but the role of CST in the regulation of cardiovascular function is unknown. In this study, we generated mice with knockout (KO) of the region of the CgA gene coding for CST (CST-KO) and found that CST-KO mice are not only hypertensive as predicted, but also display left ventricular hypertrophy, have marked macrophage infiltration of the heart and adrenal gland, and have elevated levels of pro-inflammatory cytokines and catecholamines. Intraperitoneal injection with CST reversed these phenotypes, and ischemic pre-conditioning-induced cardioprotection was also abolished in CST-KO mice. Experiments with chlodronate depletion of macrophages and bone-marrow transfer showed that macrophages produce CST and that the anti-hypertensive effects of CST are mediated in part via CSTs immunosuppression of macrophages as a form of feedback inhibition. The data thus implicate CST as a key autocrine attenuator of the cardiac inflammation in HTN by reducing macrophage inflammation.

physiology↗

bioRxiv2020

High-fidelity base editor with no detectable genome-wide off-target effects

Base editors hold promise for correcting pathogenic mutations, while substantial single nucleotide variations (SNVs) on both DNA and RNA were generated by cytosine base editors (CBEs). Here we examined possibilities to reduce off-target effects by engineering cytosine deaminases. By screening 24 CBEs harboring various rAPOBEC1 (BE3) or human APOBEC3A (BE3-hA3A) mutations on the ssDNA or RNA binding domain, we found 8 CBE variations could maintain high on-target editing efficiency. Using Genome-wide Off-target analysis by Two-cell embryo Injection (GOTI) method and RNA sequencing analysis, we found DNA off-target SNVs induced by BE3 could be completely eliminated in BE3R126E but the off-target RNA SNVs was only slightly reduced. By contrast, BE3-hA3AY130F abolished the RNA off-target effects while could not reduce the DNA off-target effects. Notably, BE3R132E, BE3W90Y+R126E and BE3W90F+R126E achieved the elimination of off-target SNVs on both DNA and RNA, suggesting the feasibility of engineering base editors for high fidelity deaminases.

genomics↗

bioRxiv2020

Prediction of meiosis-essential genes based upon the dynamic proteomes responsive to spermatogenesis

Mammalian meiosis is a specific cell division process during sexual reproduction, whereas a comprehensive proteome of the different meiotic stages has not been systematically investigated. Here, we isolated different types of spermatocytes from the testes of spermatogenesis-synchronized mice and quantified the corresponding proteomes with high-resolution mass spectrometry. A total of 8,002 proteins were identified in nine types of germ cells, and the protein signatures of spermatogenesis were characterized using the dynamic proteomes. A supervised machine learning package, FuncProFinder, was developed to predict meiosis-essential candidate genes based on changes in their protein abundance. Of the candidates without functional annotation, four of the ten genes with the highest prediction scores, Zcwpw1, Tesmin, 1700102P08Rik, and Kctd19, were validated as meiosis-essential genes using knockout mouse models. The proteomic analysis of spermatogenic cells provides a solid foundation for studying the mechanism of mammalian meiosis.

developmental biology↗

bioRxiv2019

Mitochondrial Electron Transport Chain Inhibition Suppresses LPS-Induced Inflammatory Responses via TREM1/STAT3 Pathway in BV2 Microglia

Mitochondrial damage and neuroinflammation belong to two of the most important pathological factors in multiple neurological disorders. However, the effect of mitochondrial damage of microglia on microglial activation under pathological conditions has remained unclear. In our current study, we used BV2 microglia as a cellular model to determine the effects of mitochondrial electron transport chain (ETC) inhibitors on LPS-induced inflammatory responses of microglia. We found that all of the three mitochondrial ETC inhibitors, including rotenone, sodium azide and antimycin A, significantly inhibited LPS-induced inflammatory responses of the microglia, assessed by determinations of the protein or mRNA levels of IL-1{beta}, IL-6, TNF-, iNOS and COX2. Nuclear translocation of NF-{kappa}B p65 subunit does not appear to play an important role in the mitochondrial ETC inhibition-produced suppression of microglial activation. Instead, our study found that the mitochondrial ETC inhibitors significantly attenuated not only the LPS-induced increase in the TREM1 levels - an amplifier of inflammatory process, but also the LPS-induced increase in the ratio of phosphorylated STAT3 / STAT3. In summary, our study has suggested that mitochondrial ETC inhibition of microglia can lead to suppression of LPS-induced microglial activation, which may be mediated by the inhibitory effects of mitochondrial ETC inhibition on the LPS-induced increases in the level of TREM1 and the ratio of p-STAT3 / STAT3. These findings have provided valuable information for elucidating the relationships between mitochondrial damage and neuroinflammation in multiple neurological diseases.

immunology↗

bioRxiv2019

Epidermal green autofluorescence intensity is significantly associated with the serum levels of multiple cytokines of LPS-exposed mice

Inflammation plays various crucial pathological and physiological roles, in which a number of pro-inflammatory and anti-inflammatory cytokines are important mediators. It is of great scientific and clinical significance to search for non-invasive approaches for evaluating cytokine levels in the blood. Our previous study reported that epidermal green autofluorescence (AF) intensity of LPS-exposed mice is highly correlated with LPS doses. In our current study, we determined if epidermal green AF intensity is associated with the serum levels of various cytokines in the LPS-exposed mice. We found that both epidermal green AF intensity and LPS doses are significantly associated with the serum levels of key cytokines including interleukin-1{beta} (IL-1{beta}), IL-6 and IL-10. Both epidermal green AF intensity and LPS doses are also significantly associated with the pro-inflammatory factors including IL-2, IL-12(p40), monocyte chemoattractant protein-1 (MCP-1), MIP-1, MIP-1{beta}, and regulated on activation, normal T cell expressed and secreted (RANTES/CCL5), as well as anti-inflammatory factors including IL-5 and granulocyte colony stimulating factor (G-CSF). Our findings have suggested that detection of epidermal green AF intensity may become first approach for non-invasive evaluation of certain cytokine levels in human body, which could profoundly enhance our capacity to evaluate inflammation levels for monitoring health state, disease state and therapeutic effects.

immunology↗

bioRxiv2019

Keratin-Based Epidermal Green Autofluorescence is a Common Biomarker of Organ Injury

It is critical to discover biomarkers for non-invasive evaluation of the levels of inflammation and oxidative stress in human body - two key pathological factors in numerous diseases. Our study has indicated keratin 1-based epidermal autofluorescence (AF) as a biomarker of this type: Inducers of both inflammation and oxidative stress dose-dependently increased epidermal green AF with polyhedral structure in mice, with the AF intensity being highly associated with the dosages of the inducers. Lung cancer also induced increased epidermal green AF of mice, which was mediated by inflammation. Significant and asymmetrical increases in green AF intensity with polyhedral structure were found in the Dorsal Index Fingers skin of acute ischemic stroke (AIS) patients. While the AF intensity of the subjects with high risk for developing AIS, ischemic stroke patients in recovery phase and lung cancer patients was significantly higher than that of healthy controls, both AF intensity and AF asymmetry of these four groups were markedly lower than those of the AIS patients, which have shown promise for AIS diagnosis. Several lines of evidence have indicated K1 as an origin of the AF, e.g., K1 siRNA administration attenuated the oxidative stress-induced AF increase of mice. Collectively, our study has indicated K1-based epidermal AF as a biomarker for non-invasive evaluation of the levels of inflammation and oxidative stress in the body. These findings have established a basis for novel keratins AF-based biomedical imaging technology for non-invasive, efficient and economic diagnosis and screening of such inflammation- and oxidative stress-associated diseases as AIS.

biophysics↗

bioRxiv2019

Professional Swimmers and Normal Populations have Different Patterns of Epidermal Green Autofluorescence

Our recent studies have suggested that green autofluorescence of the fingernails and certain regions of skin may be novel biomarkers for disease diagnosis and evaluation of the injury state of cardiovascular system. Our study has also suggested that oxidative stress may produce the increased epidermal green AF by altering keratin 1. Since athletes body may have increased oxidative stress and inflammation, we proposed our hypothesis that athletes may have increased green AF in their fingernails and certain regions of their skin. In current study we tested this hypothesis by determining the green AF of professional swimmers. We found that compared with age-matched controls, both the green AF intensity and AF asymmetry in both right and left antebrachium and Ventriantebrachium of the professional swimmers is significantly higher. In left Dorsal Centremetacarpus, the green AF intensity of the professional swimmers is significantly higher than that of the age-matched controls. In contrast, the green AF intensity or AF asymmetry of the professional swimmers is not significantly different from that of the age-matched controls in Centremetacarpus, Ventroforefinger, Dorsal Index Finger and Index Fingernails. Collectively, our study has provided first evidence suggesting that athletes have increased green AF intensity and asymmetry in certain regions of their skin. Based on this finding, we may evaluate non-invasively the levels of oxidative damage and inflammation in athletes body.

biophysics↗

bioRxiv2019

The green autofluorescence intensity and asymmetry of older men is significantly higher than those of older women in their fingernails and certain regions of skin

Our recent studies have suggested that the patients of multiple diseases have characteristic Pattern of Autofluorescence (AF) in their skin and fingernails, which may become novel biomarkers for both disease diagnosis and evaluation of health state. Since male populations may have higher levels of oxidative stress and inflammation than female population, in our current study we tested our hypothesis that the green AF intensity of older men is higher than that of older women in their fingernails and skin. We found that in both left and right Index Fingernails, the green AF intensity of the men of both the age group of 61 - 70 years of old and the age group of 71 - 80 years of old is significantly higher than that of the women of the same age groups. At both left Dorsal Centremetacarpus and left Centremetacarpus, the green AF intensity of the men at the age between 71 - 80 years of old is also significantly higher than that of the women of the same age group. Moreover, in Index Fingernails, Dorsal Centremetacarpus and Centremetacarpus, the green AF asymmetry of the older men of certain age groups is significantly higher than that of the women of the same age groups. Collectively, our study has provided the first evidence indicating the gender difference between the green AF intensity and asymmetry of older men and those of older women in their fingernails and certain regions of skin, which is valuable for establishing the AF-based diagnostic method.

biophysics↗

bioRxiv2018

Lipopolysaccharide (LPS) induces increased epidermal green autofluorescence of mouse

Our recent studies have suggested that characteristic Pattern of Autofluorescence (AF) of each disease could be a novel biomarker for non-invasive diagnosis of multiple major diseases such as acute ischemic stroke. It is necessary to determine if increased epidermal green AF may be produced by major pathological factors such as inflammation. In our current study, we used C57BL/6Slac mice exposed to LPS to test our hypothesis that inflammation may induce increased epidermal green AF: LPS rapidly induced significant increases in the epidermal green AF of the mices ears at 1 hr after LPS injection. LPS also dose-dependently increased the epidermal green AF. The AF intensity had a linear relationship with the LPS dosages at both 3 and 7 days after the LPS administration. The AF images exhibited the characteristic structure of the keratinocytes in Stratum Spinosum, suggesting that the origin of the increased AF was keratin 1 and/or keratin 10. Collectively, our current study has provided the first evidence indicating that inflammation can rapidly and dose-dependently induce increased epidermal green AF, suggesting that the green AF may be the first biomarker for non-invasive and rapid detection of systemic inflammation. Since inflammation is a key pathological factor of numerous diseases, our finding has highlighted the value of the epidermal AF as a novel diagnostic biomarker for numerous diseases.

biophysics↗

bioRxiv2018

NAD+ treatment can increase directly the antioxidant capacity of rotenone-treated differentiated PC12 cells

NAD+ administration can produce profound beneficial effects in the animal models of aging and a number of diseases. Since oxidative stress plays key pathological roles in aging and multiple major disorders, it is crucial to elucidate the mechanisms underlying the protective effects of NAD+ administration on oxidative stress-induced cell death. Previous studies have suggested that NAD+ treatment can decrease oxidative cell death indirectly by such mechanisms as preventing mitochondrial permeability transition, while it is unclear if NAD+ administration may decrease oxidative cell death by increasing directly the antioxidant capacity of the cells. Our current study used rotenone-treated differentiated PC12 cells as a cellular model to test our hypothesis that NAD+ treatment may increase directly the antioxidant capacity of the cells exposed to oxidative stress. Our study has indicated that NAD+ treatment can significantly attenuate the rotenone-induced increase in oxidative stress in the cells. Moreover, NAD+ treatment can significantly enhance the GSH/GSSG ratio - a major index of antioxidant capacity - of rotenone-treated cells. Collectively, our study has provided the first evidence indicating that NAD+ treatment can increase directly the antioxidant capacity of cells exposed to oxidative stress. These findings have suggested a novel mechanism underlying the profound protective effects of NAD+ administration in numerous disease models: NAD+ administration can decrease oxidative stress-induced cell death by enhancing directly the antioxidant capacity of the cells. Our finding has also highlighted the nutritional potential of NAD+.

cell biology↗

bioRxiv2018

SIRT2, ERK and Nrf2 mediate NAD+ treatment-induced increase in the antioxidant capacity of differentiated PC12 cells under basal conditions

NAD+ administration is highly beneficial in numerous models of diseases and aging. It is becoming increasingly important to determine if NAD+ treatment may increase directly the antioxidant capacity of cells under basal conditions. In current study we tested our hypothesis that NAD+ can enhance directly antioxidant capacity of cells under basal conditions by using differentiated PC12 cells as a cellular model. We found that NAD+ treatment can increase the GSH/GSSG ratios in the cells under basal conditions. NAD+ can also increase both the mRNA and protein level of {gamma}-glutamylcysteine ligase - a key enzyme for glutathione synthesis, which appears to be mediated by the NAD+-induced increase in Nrf2 activity. These NAD+-induced changes can be prevented by both SIRT2 siRNA and the SIRT2 inhibitor AGK2. The NAD+-induced changes can also be blocked by the ERK signaling inhibitor U0126. Moreover, the NAD+-induced ERK activation can be blocked by both SIRT2 siRNA and AGK2. Collectively, our study has provided the first evidence that NAD+ can enhance directly the antioxidant capacity of the cells under basal conditions, which is mediated by SIRT2, ERK, and Nrf2. These findings have suggested not only the great nutritional potential of NAD+, but also a novel mechanism underlying the protective effects of the NAD+ administration in the disease models: The NAD+ administration can enhance the resistance of the normal cells to oxidative insults by increasing the antioxidant capacity of the cells.

cell biology↗

bioRxiv2018

Base editing generates substantial off-target single nucleotide variants

Genome editing tools including CRISPR/Cas9 and base editors hold great promise for correcting pathogenic mutations. Unbiased genome-wide off-target effects of the editing in mammalian cells is required before clinical applications, but determination of the extent of off-target effects has been difficult due to the existence of single nucleotide polymorphisms (SNPs) in individuals. Here, we developed a method named GOTI (Genome-wide Off-target analysis by Two-cell embryo Injection) to detect off-target mutations without interference of SNPs. We applied GOTI to both the CRISPR-Cas9 and base editing (BE3) systems by editing one blastomere of the two-cell mouse embryo and then compared whole genome sequences of progeny-cell populations at E14.5 stage. Sequence analysis of edited and non-edited cell progenies showed that undesired off-target single nucleotide variants (SNVs) are rare (average 10.5) in CRISPR-edited mouse embryos, with a frequency close to the spontaneous mutation rate. By contrast, BE3 editing induced over 20-fold higher SNVs (average 283), raising the concern of using base-editing approaches for biomedical application.

genomics↗

bioRxiv2018

Effects of age on the green autofluorescence of the skin and fingernails of healthy persons

Our recent studies have suggested that altered Pattern of Autofluorescence (AF) of skin and fingernails are novel biomarkers of multiple major diseases. The age of all of the subjects in these studies ranges from 50 to 80 years of old. For future studies on the potential diagnostic value of green AF for age-independent diseases, it is required to answer the following question: Are there differences in the green AF of healthy persons of various age populations? In our current study, we determined the green AF of the skin and fingernails of healthy persons in several age populations, showing significant age dependence of the AF: First, the green AF intensity of the age group between 15 to 20 years of old is significantly higher than that of the age group between 50 to 80 years of old at both right and left Centremetacarpus, right Dorsal Centremetacarpus, and right Dorsal Index Finger. Second, for the green AF intensity of the age groups of 15 to 20 years of old, 60 to 70 years of old, 70 to 80 years of old, and 81 to 85 years of old, the green AF intensity is negatively correlated with the age at both right and left Centremetacarpus and right Dorsal Centremetacarpus. Collectively, our study has provided first evidence indicating the age dependence of the AF intensity of humans skin, which has established essential basis for the studies that determine the diagnostic value of the green AF for the age-independent diseases.

physiology↗

bioRxiv2018

Green autofluorescence intensity of skin and fingernails: A novel biomarker for non-invasive evaluation of pathological state of blood vessels

Stroke and myocardial infarction (MI) are two leading causes of death around the world. It is of great significance to establish novel and non-invasive approaches for evaluating pathological state of blood vessels, so that early interventions may be carried out to prevent incidence of stroke or MI. Our recent studies have suggested that altered Pattern of Autofluorescence (AF) of skin and fingernails are novel biomarkers of acute ischemic stroke (AIS) and MI. In particular, our studies have shown characteristic increases in the green AF intensity of the fingernails and certain regions of the skin of AIS patients and MI patients. By determining the skins green AF of the Healthy Group, the Low-Risk Group for Developing AIS, and the High-Risk Group for Developing AIS, our current study has indicated that the green AF intensity in the fingernails and certain regions of the skin, including the right and left Dorsal Index Fingers, Ventroforefingers, Dorsal Antebrachium and Index Fingernails as well as right Dorsal Centremetacarpus, is highly correlated with the risk to develop AIS. There is also evidence suggesting that increased oxidative stress may account for the increased AF intensity in the Low-Risk Group for Developing AIS and the High-Risk Group for Developing AIS. These findings have suggested that the green AF intensity of the fingernails and certain regions of the skin is a novel biomarker for non-invasive evaluation of the pathological state of blood vessels and the risk for developing AIS or MI.

pathology↗