| 5241. |
- Liu, Jianping, et al.
(författare)
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A human cell type similar to murine central nervous system perivascular fibroblasts
- 2021
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Ingår i: Experimental Cell Research. - : Elsevier. - 0014-4827 .- 1090-2422. ; 402:2
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Tidskriftsartikel (refereegranskat)abstract
- The brain vasculature has several specific features, one of them being the blood-brain barrier (BBB), which supports and protects the brain by allowing for the passage of oxygen and nutrients, while at the same time preventing passage of pathogens and toxins. The BBB also prevents efficient delivery of drugs to the brain, e.g. for treatment of brain tumors. In the murine brain, perivascular fibroblasts were recently identified as a novel potential constituent of the BBB. Here we present the existence of human cells that could be the equivalent to the murine brain perivascular fibroblasts. Using RNA sequencing, we show a similar transcriptomic profile of cultured human brain cells and murine perivascular fibroblasts. These data open up a window for new hypotheses on cell types involved in human CNS diseases.
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| 5242. |
- Liu, Jichao, et al.
(författare)
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Betanin inhibits PI3K/AKT/mTOR/S6 signaling pathway, cell growth and death in osteosarcoma MG-63 cells
- 2023
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Ingår i: Environmental Toxicology. - 1522-7278 .- 1520-4081. ; 38:9, s. 2173-2181
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Tidskriftsartikel (refereegranskat)abstract
- It is possible to develop new chemopreventive compounds so that cancer cells can be targeted in an exclusive manner. Bioactive natural compounds have demonstrated to be efficient chemotherapeutic agents, safe and cost-effective. Majority of anti-cancer medications are derived from natural sources, particularly of plant origins. Betanin (betanidin-5-O-β-glucoside) is the most common betacyanin with antioxidant, anti inflammatory and anticancer properties. The present study therefore investigated the effect of betanin onosteosarcoma MG-63 cells. The mechanistic pathway of inflammatory responses, cell proliferation and apoptosis were investigated. The MG-63 cells were treated with betanin for 24 h. Betanin actions on the appearance of cell arrangements, morphological changes, ROS induced Δψm, cell migration, cell adhesion and proliferative mechanistic marker expression of PI3K/AKT/mTOR/S6were analyzed. Betanin inhibited MG-63 cells at IC50 concentrations between 9.08 and 54.49 μM and induced apoptosis by triggering the ROS mechanism. Betanin inhibited proliferation and migration of MG-63 cells and induced DNA fragmentation. Betanin also modified the key mediator expression levels of PI3K/AKT/mTOR/S6 signaling pathways. Betanin can potentially be utilized in bone carcinoma therapeutics to inhibit, reverse or delay osteosarcoma.
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| 5243. |
- Liu, Jian, et al.
(författare)
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Quantitative proteomics approach reveals novel biomarkers and pathological mechanism of keloid
- 2022
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Ingår i: PROTEOMICS - Clinical Applications. - : John Wiley & Sons. - 1862-8346 .- 1862-8354. ; 16:4
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Tidskriftsartikel (refereegranskat)abstract
- Background Keloid is a pathological skin scar formation with complex and unclear molecular pathology mechanism. Novel biomarkers and associated mechanisms are needed to improve current therapies.Objectives To identify novel biomarkers and underlying pathological mechanisms of keloids.MethodsSix pairs of keloid scar tissues and corresponding normal skin tissues were quantitatively analyzed by a high-resolution label-free mass spectrometry-based proteomics approach. Differential protein expression data was further analyzed by a comprehensive bioinformatics approach to identify novel biomarkers and mechanistic pathways for keloid formation. Candidate biomarkers were validated experimentally.Results In total, 1359 proteins were identified by proteomic analysis. Of these, 206 proteins exhibited a significant difference in expression between keloid scar and normal skin tissues. RCN3 and CALU were significantly upregulated in keloids. RCN1 and PDGFRL were uniquely expressed in keloids. Pathway analysis suggested that the XBP1-mediated unfolded protein response (UPR) pathway was involved in keloid formation. Moreover, a PDGFRL centric gene coexpression network was constructed to illustrate its function in skin.Conclusions and Clinical Relevance Our study proposed four novel biomarkers and highlighted the role of XBP1-mediated UPR pathway in the pathology of keloids. It provided novel biological insights that contribute to develop novel therapeutic strategies for keloids.
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| 5244. |
- Liu, Jingyi, et al.
(författare)
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Secreted Giardia intestinalis cysteine proteases disrupt intestinal epithelial cell junctional complexes and degrade chemokines
- 2018
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Ingår i: Virulence. - : Informa UK Limited. - 2150-5594 .- 2150-5608. ; 9:1, s. 879-894
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Tidskriftsartikel (refereegranskat)abstract
- Giardiasis is a common diarrheal disease caused by the protozoan parasite Giardia intestinalis. Cysteine proteases (CPs) are acknowledged as virulence factors in Giardia but their specific role in the molecular pathogenesis of disease is not known. Herein, we aimed to characterize the three main secreted CPs (CP14019, CP16160 and CP16779), which were identified by mass spectrometry in the medium during interaction with intestinal epithelial cells (IECs) in vitro. First, the CPs were epitope-tagged and localized to the endoplasmic reticulum and cytoplasmic vesicle-like structures. Second, we showed that recombinant CPs, expressed in Pichia pastoris, are more active in acidic environment (pH 5.5-6) and we determined the kinetic parameters using fluorogenic substrates. Third, excretory-secretory proteins (ESPs) from Giardia trophozoites affect the localization of apical junctional complex (AJC) proteins and recombinant CPs cleave or re-localize the AJC proteins (claudin-1 and -4, occludin, JAM-1, beta-catenin and E-cadherin) of IECs. Finally, we showed that the ESPs and recombinant CPs can degrade several chemokines, including CXCL1, CXCL2, CXCL3, IL-8, CCL2, and CCL20, which are up-regulated in IECs during Giardia-host cell interactions. This is the first study that characterizes the role of specific CPs secreted from Giardia and our results collectively indicate their roles in the disruption of the intestinal epithelial barrier and modulating immune responses during Giardia infections.
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| 5245. |
- Liu, Jing-Xia, et al.
(författare)
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A novel type of multiterminal motor endplate in human extraocular muscles
- 2018
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Ingår i: Investigative Ophthalmology and Visual Science. - Rockville : The Association for Research in Vision and Ophthalmology. - 0146-0404 .- 1552-5783. ; 59:1, s. 539-548
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To investigate the relation between type of motor endplate, acetylcholine receptor (AChR) subunit composition, and fiber types in human extraocular muscles (EOMs).Methods: EOM samples collected from subjects aged 34 to 82 years were serially sectioned and processed for immunohistochemistry, with specific antibodies against different myosin heavy chain (MyHC) isoforms, neurofilament, synaptophysin, and adult epsilon (ε) and fetal gamma (γ) AChR subunits as well as α-bungarotoxin.Results: A novel type of motor endplate consisting of large, multiterminal en plaque endings was found in human EOMs, in addition to the previously well-described single en plaque and multiple en grappe endplates. Such novel endplates were abundant but exclusively observed in myofibers lacking MyHC slow and fast IIa but containing MyHC extraocular (MyHCeom), isoforms. Multiple en grappe endings were found only in myofibers containing MyHC slow-tonic isoform and contained fetal γ AChR subunit. Adult ε and fetal γ AChR subunits, alone or combined, were found in the multiterminal endplates. Distinct AChR subunits were present in adjacent motor endplates of a given myofiber containing MyHCeom.Conclusions: Human EOMs have a more complex innervation pattern than previously described, comprising also a novel type of multiterminal motor endplate present in myofibers containing MyHCeom. The heterogeneity in AChR subunit composition in a given myofiber suggests the possible presence of polyneuronal innervation in human EOMs.
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| 5246. |
- Liu, Jing-Xia, et al.
(författare)
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Distribution of SERCA isoforms in human intrafusal fibers
- 2003
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Ingår i: Histochemistry and Cell Biology. - : Springer. - 0948-6143 .- 1432-119X. ; 120:4, s. 299-306
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Tidskriftsartikel (refereegranskat)abstract
- The sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) is a membrane protein that plays a crucial role in muscle relaxation by transporting cytosolic Ca2+ into the lumen of the sarco/endoplasmic reticulum. In this study, the presence of SERCA1 and SERCA2 was investigated in human intrafusal fibers by immunocytochemistry. Nuclear bag1 fibers contained both SERCA1 and SERCA2 isoforms, with predominant staining seen with SERCA2 in the A and B regions. Most nuclear bag2 fibers also contained SERCA1 and SERCA2 isoforms and their coexistence frequently occurred in the A region. SERCA1 was present whereas SERCA2 was generally absent in the nuclear chain fibers. The staining intensity seen with the SERCA1 monoclonal antibody varied in the order of chain>bag1>bag2. The expression of SERCA1 isoform was found to correlate with the presence of fast myosin heavy chain (MyHC) isoform in nuclear chain fibers, whereas for nuclear bag fibers there was no such apparent correlation between patterns of expression of SERCA and MyHC isoforms. The phenotype revealed for the human bag fibers was very sophisticated and adapted to attain a very wide range of contraction and relaxation velocities.
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| 5247. |
- Liu, Jing-Xia, et al.
(författare)
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Fiber content and myosin heavy chain composition of muscle spindles in aged human biceps brachii
- 2005
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Ingår i: Journal of Histochemistry and Cytochemistry. - Baltimore : Williams & Wilkins Co.. - 0022-1554 .- 1551-5044. ; 53:4, s. 445-454
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Tidskriftsartikel (refereegranskat)abstract
- The present study investigated potential age-related changes in human muscle spindles with respect to the intrafusal fiber-type content and myosin heavy chain (MyHC) composition in biceps brachii muscle. The total number of intrafusal fibers per spindle decreased significantly with aging, due to a significant reduction in the number of nuclear chain fibers. Nuclear chain fibers in old spindles were short and some showed novel expression of MyHC alpha-cardiac. The expression of MyHC alpha-cardiac in bag1 and bag2 fibers was greatly decreased in the A region. The expression of slow MyHC was increased in nuclear bag1 fibers and that of fetal MyHC decreased in bag2 fibers whereas the patterns of distribution of the remaining MyHC isoforms were generally not affected by aging. We conclude that aging appears to have an important impact on muscle spindle composition. These changes in muscle spindle phenotype may reflect an age-related deterioration in sensory and motor innervation and are likely to have an impact in motor control in the elderly.
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| 5248. |
- Liu, Jing-Xia, et al.
(författare)
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Muscle spindles in the deep muscles of the human neck : a morphological and immunocytochemical study
- 2003
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Ingår i: Journal of Histochemistry and Cytochemistry. - : Sage Publications. - 0022-1554 .- 1551-5044. ; 51:2, s. 175-186
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Tidskriftsartikel (refereegranskat)abstract
- Muscle spindle density is extremely high in the deep muscles of the human neck. However, there is a paucity of information regarding the morphology and immunoreactivity of these muscle spindles. The objective of this study was to investigate the intrafusal fiber content and to assess the myosin heavy chain (MyHC) composition of muscle spindles from human deep neck muscles. In addition to the conventional spindles containing bag(1), bag(2), and chain fibers (b(1)b(2)c spindle), we observed a number of spindles lacking bag(1) (b(2)c spindle) or bag(2) (b(1)c spindle) fibers. Both bag(1) and bag(2) fibers contained slow tonic MyHCs along their entire fiber length and MyHCI, MyHCIIa, embryonic, and alpha-cardiac MyHC isoforms along a variable length of the fibers. Fetal MyHC was present in bag(2) fibers but not in bag(1) fibers. Nuclear chain fibers contained MyHCIIa, embryonic, and fetal isoforms with regional variations. We also compared the present data with our previous results obtained from muscle spindles in human biceps brachii and the first lumbrical muscles. The allotment of numbers of intrafusal fibers and the MyHC composition showed some muscle-related differences, suggesting functional specialization in the control of movement among different human muscles.
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| 5249. |
- Liu, Jing-Xia, et al.
(författare)
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Myosin heavy chain composition of muscle spindles in human biceps brachii
- 2002
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Ingår i: Histochem Cell Biol. ; 50:2, s. 171-184
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Tidskriftsartikel (refereegranskat)abstract
- Data on the myosin heavy chain (MyHC) composition of human muscle spindles are scarce in spite of the well-known correlation between MyHC composition and functional properties of skeletal muscle fibers. The MyHC composition of intrafusal fibers from 36 spindles of human biceps brachii muscle was studied in detail by immunocytochemistry with a large battery of antibodies. The MyHC content of isolated muscle spindles was assessed with SDS-PAGE and immunoblots. Four major MyHC isoforms (MyHCI, IIa, embryonic, and intrafusal) were detected with SDS-PAGE. Immunocytochemistry revealed very complex staining patterns for each intrafusal fiber type. The bag(1) fibers contained slow tonic MyHC along their entire fiber length and MyHCI, alpha-cardiac, embryonic, and fetal isoforms along a variable part of their length. The bag(2) fibers contained MyHC slow tonic, I, alpha-cardiac, embryonic, and fetal isoforms with regional variations. Chain fibers contained MyHCIIa, embryonic, and fetal isoforms throughout the fiber, and MyHCIIx at least in the juxtaequatorial region. Virtually each muscle spindle had a different allotment of numbers of bag(1), bag(2) and chain fibers. Taken together, the complexity in intrafusal fiber content and MyHC composition observed indicate that each muscle spindle in the human biceps has a unique identity.
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| 5250. |
- Liu, Ka‐Cheuk, et al.
(författare)
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Inhibition of Cdk5 Promotes β-Cell Differentiation From Ductal Progenitors
- 2017
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Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 67:1, s. 58-70
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Tidskriftsartikel (refereegranskat)abstract
- Inhibition of notch signaling is known to induce differentiation of endocrine cells in zebrafish and mouse. After performing an unbiased in vivo screen of ∼2,200 small molecules in zebrafish, we identified an inhibitor of Cdk5 (roscovitine), which potentiated the formation of β-cells along the intrapancreatic duct during concurrent inhibition of notch signaling. We confirmed and characterized the effect with a more selective Cdk5 inhibitor, (R)-DRF053, which specifically increased the number of duct-derived β-cells without affecting their proliferation. By duct-specific overexpression of the endogenous Cdk5 inhibitors Cdk5rap1 or Cdkal1 (which previously have been linked to diabetes in genome-wide association studies), as well as deleting cdk5, we validated the role of chemical Cdk5 inhibition in β-cell differentiation by genetic means. Moreover, the cdk5 mutant zebrafish displayed an increased number of β-cells independently of inhibition of notch signaling, in both the basal state and during β-cell regeneration. Importantly, the effect of Cdk5 inhibition to promote β-cell formation was conserved in mouse embryonic pancreatic explants, adult mice with pancreatic ductal ligation injury, and human induced pluripotent stem (iPS) cells. Thus, we have revealed a previously unknown role of Cdk5 as an endogenous suppressor of β-cell differentiation and thereby further highlighted its importance in diabetes.
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