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1.
Sensors (Basel) ; 23(21)2023 Oct 29.
Article in English | MEDLINE | ID: mdl-37960508

ABSTRACT

Sensors on autonomous vehicles have inherent physical constraints. To address these limitations, several studies have been conducted to enhance sensing capabilities by establishing wireless communication between infrastructure and autonomous vehicles. Various sensors are strategically positioned within the road infrastructure, providing essential sensory data to these vehicles. The primary challenge lies in sensor placement, as it necessitates identifying optimal locations that minimize blind spots while maximizing the sensor's coverage area. Therefore, to solve this problem, a method for positioning multiple sensor systems in road infrastructure is proposed. By introducing a voxel grid, the problem is formulated as an optimization challenge, and a genetic algorithm is employed to find a solution. Experimental findings using lidar sensors are presented to demonstrate the efficacy of this proposed approach.

2.
PLoS Genet ; 15(6): e1008214, 2019 06.
Article in English | MEDLINE | ID: mdl-31251738

ABSTRACT

Postpartum depression is a severe emotional and mental disorder that involves maternal care defects and psychiatric illness. Postpartum depression is closely associated with a combination of physical changes and physiological stress during pregnancy or after parturition in stress-sensitive women. Although postpartum depression is relatively well known to have deleterious effects on the developing fetus, the influence of genetic risk factors on the development of postpartum depression remains unclear. In this study, we discovered a novel function of T cell death-associated gene 51 (TDAG51/PHLDA1) in the regulation of maternal and depressive-like behavior. After parturition, TDAG51-deficient dams showed impaired maternal behavior in pup retrieving, nursing and nest building tests. In contrast to the normal dams, the TDAG51-deficient dams also exhibited more sensitive depressive-like behaviors after parturition. Furthermore, changes in the expression levels of various maternal and depressive-like behavior-associated genes regulating neuroendocrine factor and monoamine neurotransmitter levels were observed in TDAG51-deficient postpartum brain tissues. These findings indicate that TDAG51 plays a protective role against maternal care defects and depressive-like behavior after parturition. Thus, TDAG51 is a maternal care-associated gene that functions as a crucial regulator of maternal and depressive-like behavior after parturition.


Subject(s)
Depressive Disorder/genetics , Maternal Behavior , Parturition/genetics , Transcription Factors/genetics , Animals , Brain/metabolism , Depressive Disorder/physiopathology , Female , Gene Expression Regulation/genetics , Humans , Mice , Mice, Knockout , Neurotransmitter Agents/genetics , Parturition/physiology , Pregnancy
3.
Nanotechnology ; 31(3): 035304, 2020 Jan 17.
Article in English | MEDLINE | ID: mdl-31437819

ABSTRACT

Arrays of van der Waals gaps were manufactured by synthesizing the vertically aligned graphene layer stacked between two copper (Cu) catalytic films. The Cu-graphene-Cu laminated structure was obtained by directly synthesizing graphene on a patterned Cu film followed by depositing a second copper layer for optical measurements. The synthesis of graphene on the Cu surface was optimized by adjusting the synthesis temperatures and pre-annealing time using plasma enhanced chemical vapor deposition (PECVD). Resonant Raman spectroscopy measurements reveal that graphene can be synthesized on both bulk Cu foil and relatively thin Cu film under the same growth mechanism using PECVD. Structural and optical characterizations of the array of graphene van der Waals gaps were implemented by the transmission electron microscope and terahertz-time domain spectroscopy (THz-TDS). In THz-TDS, the measured THz amplitude transmitted through the graphene van der Waals gap slit array was constant regardless of the gap width determined by the number of graphene layers between the Cu thin films in a single slit. These results imply that the optical dielectric constant of graphene at THz frequencies in the out-of-plane direction is linearly proportional to the gap width. Our results of the manufacturing method can be adopted to investigate mechanical, electrical, and optical properties of other 2D materials such as h-BN, MoS2, and others. Furthermore, metal-graphene-metal structures with vertical orientations can be used in many electronic, optic, and optoelectronic applications.

4.
J Biol Chem ; 291(39): 20643-60, 2016 09 23.
Article in English | MEDLINE | ID: mdl-27507811

ABSTRACT

The signaling pathway downstream of stimulation of receptor activator of nuclear factor κB (RANK) by RANK ligand is crucial for osteoclastogenesis. RANK recruits TNF receptor-associated factor 6 (TRAF6) to TRAF6-binding sites (T6BSs) in the RANK cytoplasmic tail (RANKcyto) to trigger downstream osteoclastogenic signaling cascades. RANKcyto harbors an additional highly conserved domain (HCR) that also activates crucial signaling during RANK-mediated osteoclastogenesis. However, the functional cross-talk between T6BSs and the HCR in the RANK signaling complex remains unclear. To characterize the cross-talk between T6BSs and the HCR, we screened TRAF6-interacting proteins using a proteomics approach. We identified Vav3 as a novel TRAF6 binding partner and evaluated the functional importance of the TRAF6-Vav3 interaction in the RANK signaling complex. We demonstrated that the coiled-coil domain of TRAF6 interacts directly with the Dbl homology domain of Vav3 to form the RANK signaling complex independent of the TRAF6 ubiquitination pathway. TRAF6 is recruited to the RANKcyto mutant, which lacks T6BSs, via the Vav3 interaction; conversely, Vav3 is recruited to the RANKcyto mutant, which lacks the IVVY motif, via the TRAF6 interaction. Finally, we determined that the TRAF6-Vav3 interaction resulting from cross-talk between T6BSs and the IVVY motif in RANKcyto enhances downstream NF-κB, MAPK, and NFATc1 activation by further strengthening TRAF6 signaling, thereby inducing RANK-mediated osteoclastogenesis. Thus, Vav3 is a novel TRAF6 interaction partner that functions in the activation of cooperative signaling between T6BSs and the IVVY motif in the RANK signaling complex.


Subject(s)
MAP Kinase Signaling System/physiology , Multiprotein Complexes/metabolism , Osteoclasts/metabolism , Proto-Oncogene Proteins c-vav/metabolism , Receptor Activator of Nuclear Factor-kappa B/metabolism , TNF Receptor-Associated Factor 6/metabolism , Amino Acid Motifs , Cell Line , Humans , Intracellular Signaling Peptides and Proteins , Multiprotein Complexes/genetics , NFATC Transcription Factors/genetics , NFATC Transcription Factors/metabolism , Osteoclasts/cytology , Proto-Oncogene Proteins c-vav/genetics , Receptor Activator of Nuclear Factor-kappa B/genetics , TNF Receptor-Associated Factor 6/genetics , Ubiquitination/physiology
5.
Protein Expr Purif ; 131: 34-41, 2017 03.
Article in English | MEDLINE | ID: mdl-27838376

ABSTRACT

Many pesticides and chemical warfare nerve agents are highly toxic organophosphorus compounds (OPs), which inhibit acetylcholinesterase activity. Human paraoxonase 1 (PON1) has demonstrated significant potential for use as a catalytic bioscavenger capable of hydrolyzing a broad range of OPs. However, there are several limitations to the use of human PON1 as a catalytic bioscavenger, including the relatively difficult purification of PON1 from human plasma and its dependence on the presence of hydrophobic binding partners to maintain stability. Therefore, research efforts to efficiently produce recombinant human PON1 are necessary. In this study, we developed a Drosophila S2 stable cell line expressing recombinant human PON1. The recombinant human PON1 was fused with the human immunoglobulin Fc domain (PON1-hFc) to improve protein stability and purification efficiency. We purified the recombinant human PON1-hFc from the S2 stable cell line and characterized its enzymatic properties for OP hydrolysis. We purified the recombinant human PON1-hFc from the S2 stable cell line and characterized its enzymatic properties for OP hydrolysis compared with those of the recombinant human PON1 derived from E. coli. We observed that the recombinant human PON1-hFc is functionally more stable for OP hydrolyzing activities compared to the recombinant human PON1. The catalytic efficiency of the recombinant PON1-hFc towards diisopropyl fluorophosphate (DFP, 0.26 × 106 M-1 min-1) and paraoxon hydrolysis (0.015 × 106 M-1 min-1) was 1.63- and 1.24-fold higher, respectively, than the recombinant human PON1. Thus, we report that the recombinant PON1-hFc exerts hydrolytic activity against paraoxon and DFP.


Subject(s)
Aryldialkylphosphatase , Gene Expression , Immunoglobulin Fc Fragments , Recombinant Fusion Proteins , Animals , Aryldialkylphosphatase/biosynthesis , Aryldialkylphosphatase/chemistry , Aryldialkylphosphatase/genetics , Aryldialkylphosphatase/isolation & purification , Cell Line , Drosophila melanogaster , Humans , Immunoglobulin Fc Fragments/biosynthesis , Immunoglobulin Fc Fragments/chemistry , Immunoglobulin Fc Fragments/genetics , Recombinant Fusion Proteins/biosynthesis , Recombinant Fusion Proteins/chemistry , Recombinant Fusion Proteins/genetics , Recombinant Fusion Proteins/isolation & purification
6.
J Biol Chem ; 290(15): 9660-73, 2015 Apr 10.
Article in English | MEDLINE | ID: mdl-25716317

ABSTRACT

The signaling pathway downstream of TNF receptor (TNFR) is involved in the induction of a wide range of cellular processes, including cell proliferation, activation, differentiation, and apoptosis. TNFR-associated factor 2 (TRAF2) is a key adaptor molecule in TNFR signaling complexes that promotes downstream signaling cascades, such as nuclear factor-κB (NF-κB) and mitogen-activated protein kinase activation. TRAF-interacting protein (TRIP) is a known cellular binding partner of TRAF2 and inhibits TNF-induced NF-κB activation. Recent findings that TRIP plays a multifunctional role in antiviral response, cell proliferation, apoptosis, and embryonic development have increased our interest in exploring how TRIP can affect the TNFR-signaling pathway on a molecular level. In our current study, we demonstrated that TRIP is negatively involved in the TNF-induced inflammatory response through the down-regulation of proinflammatory cytokine production. Here, we demonstrated that the TRAF2-TRIP interaction inhibits Lys(63)-linked TRAF2 ubiquitination by inhibiting TRAF2 E3 ubiquitin (Ub) ligase activity. The TRAF2-TRIP interaction inhibited the binding of sphingosine 1-phosphate, which is a cofactor of TRAF2 E3 Ub ligase, to the TRAF2 RING domain. Finally, we demonstrated that TRIP functions as a negative regulator of proinflammatory cytokine production by inhibiting TNF-induced NF-κB activation. These results indicate that TRIP is an important cellular regulator of the TNF-induced inflammatory response.


Subject(s)
Lysophospholipids/metabolism , Sphingosine/analogs & derivatives , TNF Receptor-Associated Factor 2/metabolism , Tumor Necrosis Factor Receptor-Associated Peptides and Proteins/metabolism , Ubiquitin/metabolism , Binding Sites/genetics , Cytokines/genetics , Cytokines/metabolism , Gene Expression , HEK293 Cells , HeLa Cells , Humans , Immunoblotting , Lysine/genetics , Lysine/metabolism , NF-kappa B/metabolism , Protein Binding , RNA Interference , Reverse Transcriptase Polymerase Chain Reaction , Signal Transduction/drug effects , Sphingosine/metabolism , TNF Receptor-Associated Factor 2/genetics , Tumor Necrosis Factor Receptor-Associated Peptides and Proteins/genetics , Tumor Necrosis Factor-alpha/genetics , Tumor Necrosis Factor-alpha/metabolism , Tumor Necrosis Factor-alpha/pharmacology , Ubiquitination
7.
J Biol Chem ; 289(52): 35868-81, 2014 Dec 26.
Article in English | MEDLINE | ID: mdl-25359771

ABSTRACT

Genetic mutations in osteoclastogenic genes are closely associated with osteopetrotic bone diseases. Genetic defects in OSTM1 (osteopetrosis-associated transmembrane protein 1) cause autosomal recessive osteopetrosis in humans. In particular, OSTM1 mutations that exclude the transmembrane domain might lead to the production of a secreted form of truncated OSTM1. However, the precise role of the secreted form of truncated OSTM1 remains unknown. In this study, we analyzed the functional role of truncated OSTM1 in osteoclastogenesis. Here, we showed that a secreted form of truncated OSTM1 binds to the cell surface of osteoclast (OC) precursors and inhibits the formation of multinucleated OCs through the reduction of cell fusion and survival. Truncated OSTM1 significantly inhibited the expression of OC marker genes through the down-regulation of the BLIMP1 (B lymphocyte-induced maturation protein 1)-NFATc1 (nuclear factor of activated T cells c1) axis. Finally, we demonstrated that truncated OSTM1 reduces lipopolysaccharide-induced bone destruction in vivo. Thus, these findings suggest that autosomal recessive osteopetrosis patients with an OSTM1 gene mutation lacking the transmembrane domain produce a secreted form of truncated OSTM1 that inhibits osteoclastogenesis.


Subject(s)
Membrane Proteins/metabolism , NFATC Transcription Factors/metabolism , Osteoclasts/physiology , Transcription Factors/metabolism , Animals , Bone Resorption/immunology , Bone Resorption/metabolism , Cell Differentiation , Cell Fusion , Cell Survival , Cells, Cultured , Down-Regulation , Gene Expression , Lipopolysaccharides/pharmacology , Male , Membrane Proteins/genetics , Mice, Inbred C57BL , Osteoclasts/immunology , Osteoporosis/immunology , Osteoporosis/metabolism , Positive Regulatory Domain I-Binding Factor 1 , Signal Transduction
8.
Health Sci Rep ; 5(6): e856, 2022 Nov.
Article in English | MEDLINE | ID: mdl-36210871

ABSTRACT

Background and aims: Despite global vaccination efforts, the number of confirmed cases of coronavirus disease 2019 (COVID-19) remains high. To overcome the crisis precipitated by the ongoing pandemic, characteristic studies such as virus diagnosis, isolation, and genome analysis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are necessary. Herein, we report the isolation and molecular characterization of SARS-CoV-2 from the saliva of patients who had tested positive for COVID-19 at Proving Ground in Taean County, Republic of Korea, in 2020. Methods: We analyzed the whole-genome sequence of SARS-CoV-2 isolated from the saliva samples of patients through next-generation sequencing. We also successfully isolated SARS-CoV-2 from the saliva samples of two patients by using cell culture, which was used to study the cytopathic effects and viral replication in Vero E6 cells. Results: Whole-genome sequences of the isolates, SARS-CoV-2 ADD-2 and ADD-4, obtained from saliva were identical, and phylogenetic analysis using Bayesian inference methods showed SARS-CoV-2 GH clade (B.1.497) genome-specific clustering. Typical coronavirus-like particles, with diameters of 70-120 nm, were observed in the SARS-CoV-2 infected Vero E6 cells using transmission electron microscopy. Conclusion: In conclusion, this report provides insights into the molecular diagnosis, isolation, genetic characteristics, and diversity of SARS-CoV-2 isolated from the saliva of patients. Further studies are needed to explore and monitor the evolution and characteristics of SARS-CoV-2 variants.

9.
Pathogens ; 11(9)2022 Sep 14.
Article in English | MEDLINE | ID: mdl-36145479

ABSTRACT

Seoul virus (SEOV), an etiological agent for hemorrhagic fever with renal syndrome, poses a significant public health threat worldwide. This study evaluated the feasibility of a mobile Biomeme platform for facilitating rapid decision making of SEOV infection. A total of 27 Rattus norvegicus were collected from Seoul Metropolitan City and Gangwon Province in Republic of Korea (ROK), during 2016-2020. The serological and molecular prevalence of SEOV was 5/27 (18.5%) and 2/27 (7.4%), respectively. SEOV RNA was detected in multiple tissues of rodents using the Biomeme device, with differences in Ct values ranging from 0.6 to 2.1 cycles compared to a laboratory benchtop system. Using amplicon-based next-generation sequencing, whole-genome sequences of SEOV were acquired from lung tissues of Rn18-1 and Rn19-5 collected in Gangwon Province. Phylogenetic analysis showed a phylogeographical diversity of rat-borne orthohantavirus collected in Gangwon Province. We report a novel isolate of SEOV Rn19-5 from Gangwon Province. Our findings demonstrated that the Biomeme system can be applied for the molecular diagnosis of SEOV comparably to the laboratory-based platform. Whole-genome sequencing of SEOV revealed the phylogeographical diversity of orthohantavirus in the ROK. This study provides important insights into the field-deployable diagnostic assays and genetic diversity of orthohantaviruses for the rapid response to hantaviral outbreaks in the ROK.

10.
PLoS Negl Trop Dis ; 16(9): e0010763, 2022 09.
Article in English | MEDLINE | ID: mdl-36094957

ABSTRACT

BACKGROUND: Whole-genome sequencing plays a critical role in the genomic epidemiology intended to improve understanding the spread of emerging viruses. Dabie bandavirus, causing severe fever with thrombocytopenia syndrome (SFTS), is a zoonotic tick-borne virus that poses a significant public health threat. We aimed to evaluate a novel amplicon-based nanopore sequencing tool to obtain whole-genome sequences of Dabie bandavirus, also known as SFTS virus (SFTSV), and investigate the molecular prevalence in wild ticks, Republic of Korea (ROK). PRINCIPAL FINDINGS: A total of 6,593 ticks were collected from Gyeonggi and Gangwon Provinces, ROK in 2019 and 2020. Quantitative polymerase chain reaction revealed the presence of SFSTV RNA in three Haemaphysalis longicornis ticks. Two SFTSV strains were isolated from H. longicornis captured from Pocheon and Cheorwon. Multiplex polymerase chain reaction-based nanopore sequencing provided nearly full-length tripartite genome sequences of SFTSV within one hour running. Phylogenetic and reassortment analyses were performed to infer evolutionary relationships among SFTSVs. Phylogenetic analysis grouped SFTSV Hl19-31-4 and Hl19-31-13 from Pocheon with sub-genotype B-1 in all segments. SFTSV Hl20-8 was found to be a genomic organization compatible with B-1 (for L segment) and B-2 (for M and S segments) sub-genotypes, indicating a natural reassortment between sub-genotypes. CONCLUSION/SIGNIFICANCE: Amplicon-based next-generation sequencing is a robust tool for whole-genome sequencing of SFTSV using the nanopore platform. The molecular prevalence and geographical distribution of SFTSV enhanced the phylogeographic map at high resolution for sophisticated prevention of emerging SFTS in endemic areas. Our findings provide important insights into the rapid whole-genome sequencing and genetic diversity for the genome-based diagnosis of SFTSV in the endemic outbreak.


Subject(s)
Bunyaviridae Infections , Nanopore Sequencing , Phlebovirus , Severe Fever with Thrombocytopenia Syndrome , Ticks , Animals , Bunyaviridae Infections/epidemiology , Genetic Variation , Multiplex Polymerase Chain Reaction , Phlebovirus/genetics , Phylogeny , RNA , Republic of Korea/epidemiology
11.
J Microbiol Biotechnol ; 31(1): 144-153, 2021 Jan 28.
Article in English | MEDLINE | ID: mdl-33144547

ABSTRACT

Organophosphorus nerve agents (OPNAs), including both G- and V-type nerve agents such as sarin, soman, tabun and VX, are extremely neurotoxic organophosphorus compounds. Catalytic bioscavengers capable of hydrolyzing OPNAs are under development because of the low protective effects and adverse side effects of chemical antidotes to OPNA poisoning. However, these bioscavengers have certain limitations for practical application, including low catalytic activity and narrow specificity. In this study, we generated a fusion-hybrid form of engineered recombinant human paraoxonase 1 (rePON1) and bacterial organophosphorus hydrolase (OPH), referred to as GV-hybrids, using a flexible linker to develop more promising catalytic bioscavengers against a broad range of OPNAs. These GV-hybrids were able to synergistically hydrolyze both G-type OPNA analogs (paraoxon: 1.7 ~ 193.7-fold, p-nitrophenyl diphenyl phosphate (PNPDPP): 2.3 ~ 33.0-fold and diisopropyl fluorophosphates (DFP): 1.4 ~ 22.8-fold) and V-type OPNA analogs (demeton-Smethyl (DSM): 1.9 ~ 34.6-fold and malathion: 1.1 ~ 4.2-fold above) better than their individual enzyme forms. Among the GV-hybrid clones, the GV7 clone showed remarkable improvements in the catalytic activity toward both G-type OPNA analogs (kcat/Km (106 M-1 min-1): 59.8 ± 0.06 (paraoxon), 5.2 ± 0.02 (PNPDPP) and 47.0 ± 6.0 (DFP)) and V-type OPNA analogs (kcat/Km (M-1 min-1): 504.3 ± 48.5 (DSM) and 1324.0 ± 47.5 (malathion)). In conclusion, we developed GV-hybrid forms of rePON1 and bacterial OPH mutants as effective and suitable catalytic bioscavengers to hydrolyze a broad range of OPNA analogs.


Subject(s)
Aryldialkylphosphatase/genetics , Aryldialkylphosphatase/pharmacology , Genetic Engineering/methods , Nerve Agents/chemistry , Recombinant Fusion Proteins/genetics , Antidotes , Aryldialkylphosphatase/chemistry , Catalysis , Humans , Hydrolysis , Organophosphates , Organophosphorus Compounds/chemistry , Organophosphorus Compounds/pharmacology , Phosphoric Triester Hydrolases , Substrate Specificity
12.
Mol Cells ; 44(1): 1-12, 2021 01 31.
Article in English | MEDLINE | ID: mdl-33335079

ABSTRACT

The nuclear receptor peroxisome proliferator-activated receptor γ (PPARγ) is the master transcriptional regulator in adipogenesis. PPARγ forms a heterodimer with another nuclear receptor, retinoid X receptor (RXR), to form an active transcriptional complex, and their transcriptional activity is tightly regulated by the association with either coactivators or corepressors. In this study, we identified T-cell death-associated gene 51 (TDAG51) as a novel corepressor of PPARγ-mediated transcriptional regulation. We showed that TDAG51 expression is abundantly maintained in the early stage of adipogenic differentiation. Forced expression of TDAG51 inhibited adipocyte differentiation in 3T3-L1 cells. We found that TDAG51 physically interacts with PPARγ in a ligand-independent manner. In deletion mutant analyses, large portions of the TDAG51 domains, including the pleckstrin homology-like, glutamine repeat and proline-glutamine repeat domains but not the proline-histidine repeat domain, are involved in the interaction with the region between residues 140 and 506, including the DNA binding domain, hinge, ligand binding domain and activation function-2 domain, in PPARγ. The heterodimer formation of PPARγ-RXRα was competitively inhibited in a ligand-independent manner by TDAG51 binding to PPARγ. Thus, our data suggest that TDAG51, which could determine adipogenic cell fate, acts as a novel negative regulator of PPARγ by blocking RXRα recruitment to the PPARγ-RXRα heterodimer complex in adipogenesis.


Subject(s)
Adipogenesis , PPAR gamma/metabolism , Protein Multimerization , Retinoid X Receptor alpha/metabolism , T-Lymphocytes/cytology , T-Lymphocytes/metabolism , Transcription Factors/genetics , 3T3-L1 Cells , Adipocytes/cytology , Adipocytes/metabolism , Animals , Cell Death , Fatty Acid-Binding Proteins/genetics , Fatty Acid-Binding Proteins/metabolism , Mice , Promoter Regions, Genetic/genetics , Protein Binding , Transcription Factors/metabolism
13.
Immune Netw ; 18(1): e8, 2018 Feb.
Article in English | MEDLINE | ID: mdl-29503739

ABSTRACT

Cytokines play a pivotal role in maintaining bone homeostasis. Osteoclasts (OCs), the sole bone resorbing cells, are regulated by numerous cytokines. Macrophage colony-stimulating factor and receptor activator of NF-κB ligand play a central role in OC differentiation, which is also termed osteoclastogenesis. Osteoclastogenic cytokines, including tumor necrosis factor-α, IL-1, IL-6, IL-7, IL-8, IL-11, IL-15, IL-17, IL-23, and IL-34, promote OC differentiation, whereas anti-osteoclastogenic cytokines, including interferon (IFN)-α, IFN-ß, IFN-γ, IL-3, IL-4, IL-10, IL-12, IL-27, and IL-33, downregulate OC differentiation. Therefore, dynamic regulation of osteoclastogenic and anti-osteoclastogenic cytokines is important in maintaining the balance between bone-resorbing OCs and bone-forming osteoblasts (OBs), which eventually affects bone integrity. This review outlines the osteoclastogenic and anti-osteoclastogenic properties of cytokines with regard to osteoimmunology, and summarizes our current understanding of the roles these cytokines play in osteoclastogenesis.

14.
Exp Mol Med ; 49(11): e400, 2017 11 24.
Article in English | MEDLINE | ID: mdl-29170473

ABSTRACT

B lymphocytes are produced from hematopoietic stem cells (HSCs) through the highly ordered process of B lymphopoiesis, which is regulated by a complex network of cytokines, chemokines and cell adhesion molecules derived from the hematopoietic niche. Primary osteoblasts function as an osteoblastic niche (OBN) that supports in vitro B lymphopoiesis. However, there are significant limitations to the use of primary osteoblasts, including their relative scarcity and the consistency and efficiency of the limited purification and proliferation of these cells. Thus, development of a stable osteoblast cell line that can function as a biomimetic or artificial OBN is necessary. In this study, we developed a stable osteoblastic cell line, designated OBN4, which functions as an osteoblast-based artificial niche that supports in vitro B lymphopoiesis. We demonstrated that the production of a B220+ cell population from Lineage- (Lin-) Sca-1+ c-Kit+ hematopoietic stem and progenitor cells (HSPCs) was increased ~1.7-fold by OBN4 cells relative to production by primary osteoblasts and OP9 cells in coculture experiments. Consistently, OBN4 cells exhibited the highest production of B220+ IgM+ cell populations (6.7±0.6-13.6±0.6%) in an IL-7- and stromal cell-derived factor 1-dependent manner, with higher production than primary osteoblasts (3.7±0.5-6.4±0.6%) and OP9 cells (1.8±0.6-3.9±0.5%). In addition, the production of B220+ IgM+ IgD+ cell populations was significantly enhanced by OBN4 cells (15.4±1.1-18.9±3.2%) relative to production by primary osteoblasts (9.5±0.6-14.6±1.6%) and OP9 cells (9.1±0.5-10.3±1.8%). We conclude that OBN4 cells support in vitro B lymphopoiesis of Lin- Sca-1+ c-Kit+ HSPCs more efficiently than primary osteoblasts or OP9 stromal cells.


Subject(s)
B-Lymphocytes/cytology , B-Lymphocytes/metabolism , Cell Differentiation , Lymphopoiesis , Animals , Biomarkers , Cell Line , Cell Separation , Hematopoietic Stem Cells/cytology , Hematopoietic Stem Cells/metabolism , Immunophenotyping , Male , Mice , Osteoblasts/cytology , Osteoblasts/metabolism , Stem Cell Niche
15.
Protein Pept Lett ; 24(7): 617-625, 2017.
Article in English | MEDLINE | ID: mdl-28462712

ABSTRACT

BACKGROUND: Human prolidase has weak hydrolytic activity for toxic organophosphorus compounds including diisopropyl fluorophosphates (DFP), chemical warfare nerve agents and pesticides. OBJECTIVES: In order to use human prolidase as a catalytic bioscavenger against toxic organophosphorus compound exposure, protein engineering is an important issue to improve the catalytic activity of human prolidase towards the hydrolysis of toxic organophosphorus compounds. METHOD: We developed two human prolidase mutants, A252R and P365R, with a single amino acid substitution using in silico analysis based on the sequence, protein structure and stability to improve the catalytic activity of human prolidase towards DFP hydrolysis. RESULTS: Our results showed that the catalytic efficiencies of A252R and P365R towards DFP hydrolysis were 1.23- and 1.36-fold increases, respectively, than that of the wild type, while the prolidase activities of A252R and P365R towards Leu-Pro hydrolysis were 0.88- and 0.78-fold decreases that of the wild type, respectively, indicating that substitution mutations of A252R and P365R in human prolidase show improved hydrolytic activity for toxic organophosphorus compounds. CONCLUSION: We report here that by introducing either the A252R or P365R substitution mutation, the structural changes affecting catalytic turnover rate and substrate binding affinity are valuable in improving the catalytic activity of human prolidase towards toxic organophosphorus compound hydrolysis.


Subject(s)
Catalysis , Dipeptidases/chemistry , Mutant Proteins/chemistry , Amino Acid Substitution , Chemical Warfare Agents/chemistry , Chemical Warfare Agents/toxicity , Dipeptidases/genetics , Humans , Hydrolysis , Mutant Proteins/genetics , Organophosphorus Compounds/chemistry , Organophosphorus Compounds/toxicity , Protein Engineering
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