Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 178
Filter
Add more filters

Country/Region as subject
Publication year range
1.
Eur J Immunol ; 54(3): e2350836, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38234007

ABSTRACT

T lymphocytes are pivotal in adaptive immunity. The role of the trafficking protein particle complex (TRAPPC) in regulating T-cell development and homeostasis is unknown. Using CD4cre -Trappc1flox/flox (Trappc1 cKO) mice, we found that Trappc1 deficiency in T cells significantly decreased cell number of naive T cells in the periphery, whereas thymic T-cell development in Trappc1 cKO mice was identical as WT mice. In the culture assays and mouse models with adoptive transfer of the sorted WT (CD45.1+ CD45.2+ ) and Trappc1 cKO naive T cells (CD45.2+ ) to CD45.1+ syngeneic mice, Trappc1-deficient naive T cells showed significantly reduced survival ability compared with WT cells. RNA-seq and molecular studies showed that Trappc1 deficiency in naive T cells reduced protein transport from the endoplasmic reticulum to the Golgi apparatus, enhanced unfolded protein responses, increased P53 transcription, intracellular Ca2+ , Atf4-CHOP, oxidative phosphorylation, and lipid peroxide accumulation, and subsequently led to ferroptosis. Trappc1 deficiency in naive T cells increased ferroptosis-related damage-associated molecular pattern molecules like high mobility group box 1 or lipid oxidation products like prostaglandin E2, leukotriene B4, leukotriene C4, and leukotriene D4. Functionally, the culture supernatant of Trappc1 cKO naive T cells significantly promoted neutrophils to express inflammatory cytokines like TNFα and IL-6, which was rescued by lipid peroxidation inhibitor Acetylcysteine. Importantly, Trappc1 cKO mice spontaneously developed severe autoinflammatory disease 4 weeks after birth. Thus, intrinsic expression of Trappc1 in naive T cells plays an integral role in maintaining T-cell homeostasis to avoid proinflammatory naive T-cell death-caused autoinflammatory syndrome in mice. This study highlights the importance of the TRAPPC in T-cell biology.


Subject(s)
Ferroptosis , Hereditary Autoinflammatory Diseases , Mice , Animals , T-Lymphocytes , Mice, Knockout , Cell Differentiation
2.
EMBO Rep ; 24(2): e55503, 2023 02 06.
Article in English | MEDLINE | ID: mdl-36440617

ABSTRACT

Myeloid cell development in bone marrow is essential for the maintenance of peripheral immune homeostasis. However, the role of intracellular protein trafficking pathways during myeloid cell differentiation is currently unknown. By mining bioinformatics data, we identify trafficking protein particle complex subunit 1 (TRAPPC1) as continuously upregulated during myeloid cell development. Using inducible ER-TRAPPC1 knockout mice and bone marrow chimeric mouse models, we demonstrate that TRAPPC1 deficiency causes severe monocyte and neutrophil defects, accompanied by a selective decrease in common myeloid progenitors (CMPs) and subsequent cell subsets in bone marrow. TRAPPC1-deleted CMPs differentiate poorly into monocytes and neutrophils in vivo and in vitro, in addition to exhibiting enhanced endoplasmic reticulum stress and apoptosis via a Ca2+ -mitochondria-dependent pathway. Cell cycle arrest and senescence of TRAPPC1-deleted CMPs are mediated by the activation of pancreatic endoplasmic reticulum kinase and the upregulation of cyclin-dependent kinase inhibitor p21. This study reveals the essential role of TRAPPC1 in the maintenance and differentiation of CMPs and highlights the significance of protein processing and trafficking processes in myeloid cell development.


Subject(s)
Bone Marrow , Myeloid Progenitor Cells , Vesicular Transport Proteins , Animals , Mice , Bone Marrow/metabolism , Cell Differentiation , Mice, Knockout , Monocytes , Myeloid Progenitor Cells/metabolism , Neutrophils , Vesicular Transport Proteins/metabolism
3.
BMC Cancer ; 24(1): 849, 2024 Jul 17.
Article in English | MEDLINE | ID: mdl-39020276

ABSTRACT

BACKGROUND: Numerous meta-analyses and clinical studies have shown that subtypes of immune cells are associated with the development of skin cancer, but it is not clear whether this association is causal or biased. Mendelian randomization (MR) analysis reduces the effect of confounding factors and improves the accuracy of the results when compared to traditional studies. Thus, in order to examine the causal relationship between various immune cell and skin cancer, this study employs two-sample MR. METHODS: This study assesses the causal association between 731 immune cell characteristics and skin cancer using a two-sample Mendel randomization (MR) methodology. Multiple MR methods were used to bias and to derive reliable estimates of causality between instrumental variables and outcomes. Comprehensive sensitivity analyses were used to validate the stability, heterogeneity and horizontal multiplicity of the results. RESULTS: We discovered that potential causal relationships between different types of immune cells and skin cancer disease. Specifically, one type of immune cell as potentially causal to malignant melanoma of skin (MM), eight different types of immune cells as potentially causal to basal cell carcinoma (BCC), four different types of immune cells as potentially causal to actinic keratosis (AK), and no different types of immune cells were found to have a potential causal association with squamous cell carcinoma(SCC), with stability in all of the results. CONCLUSION: This study demonstrates the close connection between immune cells and skin cancer disease by genetic means, which enriches the current knowledge about the role of immune cells in skin cancer and also contributes to the design of therapeutic strategies from an immunological perspective.


Subject(s)
Melanoma , Mendelian Randomization Analysis , Skin Neoplasms , Humans , Skin Neoplasms/genetics , Skin Neoplasms/immunology , Melanoma/genetics , Melanoma/immunology , Carcinoma, Basal Cell/genetics , Carcinoma, Basal Cell/immunology , Carcinoma, Squamous Cell/genetics , Carcinoma, Squamous Cell/immunology , Keratosis, Actinic/genetics , Keratosis, Actinic/immunology , Polymorphism, Single Nucleotide
4.
Physiol Plant ; 176(5): e14559, 2024.
Article in English | MEDLINE | ID: mdl-39377160

ABSTRACT

Litchi (Litchi chinensis Sonn.) has a desirable sweet taste and exotic aroma, making it popular in the markets. However, the biosynthesis of aroma volatiles in litchi fruit has rarely been investigated. In this study, the content and composition of volatile compounds were determined during litchi fruit ripening. In the mature green and mature red stages of litchi, 49 and 45 volatile compounds were detected, respectively. Monoterpenes were found to be the most abundant volatile compounds in mature red fruit, and their contents significantly increased compared to green fruit, mainly including citronellol, geraniol, myrcene, and D-limonene, which contributed to the aroma in litchi fruit. By comparing the expression profiles of the genes involved in the terpene synthesis pathway during fruit development, a terpene synthesis gene (LcTPS1-2) was identified and characterized as a major player in the synthesis of monoterpenes and sesquiterpenes. A subcellular localization analysis found LcTPS1-2 to be present in the plastid and cytoplasm. The recombinant LcTPS1-2 enzyme was able to catalyze the formation of three monoterpenes, myrcene, geraniol and citral, from geranyl pyrophosphate (GPP) and to convert farnesyl diphosphate (FPP) to a sesquiterpene, caryophyllene in vitro. Transgenic Arabidopsis thaliana plants overexpressing LcTPS1-2 exclusively released one monoterpene D-limonene, and three sesquiterpenes cis-thujopsene, (E)-ß-famesene and trans-ß-ionone. These results indicate that LcTPS1-2 plays an important role in the production of major volatile terpenes in litchi fruit and provides a basis for future investigations of terpenoid biosynthesis in litchi and other horticultural crops.


Subject(s)
Fruit , Litchi , Monoterpenes , Plant Proteins , Sesquiterpenes , Volatile Organic Compounds , Fruit/metabolism , Fruit/genetics , Fruit/growth & development , Litchi/genetics , Litchi/metabolism , Sesquiterpenes/metabolism , Monoterpenes/metabolism , Volatile Organic Compounds/metabolism , Plant Proteins/genetics , Plant Proteins/metabolism , Gene Expression Regulation, Plant , Terpenes/metabolism , Acyclic Monoterpenes/metabolism
5.
J Periodontal Res ; 59(2): 366-380, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38189472

ABSTRACT

BACKGROUND AND OBJECTIVE: As a chronic inflammatory disease, periodontitis threatens oral health and is a risk factor for Alzheimer's disease (AD). There is growing evidence that these two diseases are closely related. However, current research is still incomplete in understanding the common genes and common mechanisms between periodontitis and AD. In this study, we aimed to identify common genes in periodontitis and AD and analyze the relationship between crucial genes and immune cells to provide new therapeutic targets for clinical treatment. MATERIALS AND METHODS: We evaluated differentially expressed genes (DEGs) specific to periodontitis and AD. Co-expressed genes were identified by obtaining gene expression profile data from the Gene Expression Omnibus (GEO) database. Using the STRING database, protein-protein interaction (PPI) networks were constructed, and essential genes were identified. We also used four algorithms to identify critical genes and constructed regulatory networks. The association of crucial genes with immune cells and potential therapeutic effects was also assessed. RESULTS: PDGFRB, VCAN, TIMP1, CHL1, EFEMP2, and IGFBP5 were obtained as crucial common genes. Immune infiltration analysis showed that Natural killer cells and Myeloid-derived suppressor cells were significantly differentially expressed in patients with PD and AD compared with the normal group. FOXC1 and GATA2 are important TFs for PD and AD. MiR-23a, miR-23b, miR-23a, and miR-23b were associated with AD and PD. Finally, the hub genes retrieved from the DSigDB database indicate multiple drug molecule and drug-target interactions. CONCLUSION: This study reveals commonalities in common hub genes and immune infiltration between periodontitis and AD, and the analysis of six hub genes and immune cells may provide new insights into potential therapeutic directions for the pathogenesis of periodontitis complicated by AD.


Subject(s)
Alzheimer Disease , MicroRNAs , Periodontitis , Humans , Alzheimer Disease/genetics , Periodontitis/genetics , Periodontitis/therapy , Computational Biology , Databases, Factual , Gene Expression Profiling
6.
J Immunol ; 209(11): 2181-2191, 2022 12 01.
Article in English | MEDLINE | ID: mdl-36426981

ABSTRACT

Fatty acid binding protein 5 (FABP5) is mainly involved in the uptake, transport, and metabolism of fatty acid in the cytoplasm, and its role in immune cells has been recognized in recent years. However, the role of FABP5 in macrophage inflammation and its underlying mechanisms were not fully addressed. In our study, the acute liver injury and sepsis mouse models were induced by i.p. injection of LPS and cecal contents, respectively. Oleic acid (0.6 g/kg) was injected four times by intragastric administration every week, and this lasted for 1 wk before the LPS or cecal content challenge. We found that myeloid-specific deletion of FABP5 mitigated LPS-induced acute liver injury with reduced mortality of mice, histological liver damage, alanine aminotransferase, and proinflammatory factor levels. Metabolic analysis showed that FABP5 deletion increased the intracellular unsaturated fatty acids, especially oleic acid, in LPS-induced macrophages. The addition of oleic acid also decreased LPS-stimulated macrophage inflammation in vitro and reduced acute liver injury in LPS-induced or cecal content-induced sepsis mice. RNA-sequencing and molecular mechanism studies showed that FABP5 deletion or oleic acid supplementation increased the AMP/ATP ratio and AMP-activated protein kinase (AMPK) activation and inhibited the NF-κB pathway during the inflammatory response to LPS stimulation of macrophages. Inhibiting AMPK activation or expression by chemical or genetic approaches significantly rescued the decreased NF-κB signaling pathway and inflammatory response in LPS-treated FABP5-knockout macrophages. Our present study indicated that inhibiting FABP5 or supplementation of oleic acid might be used for the treatment of sepsis-caused acute liver injury.


Subject(s)
NF-kappa B , Sepsis , Mice , Animals , AMP-Activated Protein Kinases , Lipopolysaccharides , Signal Transduction , Macrophages , Inflammation , Oleic Acids , Neoplasm Proteins , Fatty Acid-Binding Proteins/genetics
7.
Cereb Cortex ; 33(13): 8352-8367, 2023 06 20.
Article in English | MEDLINE | ID: mdl-37083264

ABSTRACT

Numerous functional magnetic resonance imaging (fMRI) studies have examined the neural mechanisms of negative emotional words, but scarce evidence is available for the interactions among related brain regions from the functional brain connectivity perspective. Moreover, few studies have addressed the neural networks for negative word processing in bilinguals. To fill this gap, the current study examined the brain networks for processing negative words in the first language (L1) and the second language (L2) with Chinese-English bilinguals. To identify objective indicators associated with negative word processing, we first conducted a coordinate-based meta-analysis on contrasts between negative and neutral words (including 32 contrasts from 1589 participants) using the activation likelihood estimation method. Results showed that the left medial prefrontal cortex (mPFC), the left inferior frontal gyrus (IFG), the left posterior cingulate cortex (PCC), the left amygdala, the left inferior temporal gyrus (ITG), and the left thalamus were involved in processing negative words. Next, these six clusters were used as regions of interest in effective connectivity analyses using extended unified structural equation modeling to pinpoint the brain networks for bilingual negative word processing. Brain network results revealed two pathways for negative word processing in L1: a dorsal pathway consisting of the left IFG, the left mPFC, and the left PCC, and a ventral pathway involving the left amygdala, the left ITG, and the left thalamus. We further investigated the similarity and difference between brain networks for negative word processing in L1 and L2. The findings revealed similarities in the dorsal pathway, as well as differences primarily in the ventral pathway, indicating both neural assimilation and accommodation across processing negative emotion in two languages of bilinguals.


Subject(s)
Multilingualism , Humans , Brain Mapping , Language , Brain/diagnostic imaging , Brain/physiology , Emotions , Neural Pathways/diagnostic imaging , Neural Pathways/physiology , Magnetic Resonance Imaging
8.
Eur J Neurosci ; 57(5): 840-853, 2023 03.
Article in English | MEDLINE | ID: mdl-36656284

ABSTRACT

How speaking two languages affects executive functions has been a long-standing debate and the mechanisms underlying the observed cognitive advantages of bilingualism remain unspecified. Here, using multivariate pattern classification methods, we decoded spatial patterns of neural signals associated with Flanker task performance in mono-dialectal and bi-dialectal speakers of Chinese. While univariate approach to even-related potentials (ERPs) showed no between-group difference, decoding accuracy of ERPs was reduced in bi-dialectal as compared to mono-dialectal speakers in both congruent-neutral and incongruent-neutral classifications. There was no effect of bidialectalism, however, on decoding accuracy of alpha-band oscillations, an electrophysiological index implicated in inhibition. Behavioural data analysed using the Drift Diffusion Model (DDM) showed facilitating effects of bidialectalism on non-decision times but no effect on drift rates. These findings demonstrate that using two dialects on a daily basis enhances general attentional deployment rather than affecting specific component of executive functions such as inhibitory control. Given that the two dialects of Chinese differed almost exclusively in phonology, the bidialectalism effect was most likely motivated by resolving phonological competition at lexical processing level.


Subject(s)
Executive Function , Multilingualism , Executive Function/physiology , Language , Attention/physiology
9.
Eur J Immunol ; 52(11): 1789-1804, 2022 11.
Article in English | MEDLINE | ID: mdl-35908180

ABSTRACT

Thymic epithelial cells (TECs) are important for T cell development and immune tolerance establishment. Although comprehensive molecular regulation of TEC development has been studied, the role of transport protein particle complexes (Trappcs) in TECs is not clear. Using TEC-specific homozygous or heterozygous Trappc1 deleted mice model, we find that Trappc1 deficiency cause severe thymus atrophy with decreased cell number and blocked maturation of TECs. Mice with a TEC-specific Trappc1 deletion show poor thymic T cell output and have a greater percentage of activated/memory T cells, suffered from spontaneous autoimmune disorders. Our RNA-seq and molecular studies indicated that the decreased endoplasmic reticulum (ER) and Golgi apparatus, enhanced unfolded protein response (UPR) and subsequent Atf4-CHOP-mediated apoptosis, and reactive oxygen species (ROS)-mediated ferroptosis coordinately contributed to the reduction of Trappc1-deleted TECs. Additionally, reduced Aire+ mTECs accompanied by the decreased expression of Irf4, Irf8, and Tbx21 in Trappc1 deficiency mTECs, may further coordinately block the tissue-restricted antigen expression. In this study, we reveal that Trappc1 plays an indispensable role in TEC development and maturation and provide evidence for the importance of inter-organelle traffic and ER homeostasis in TEC development.


Subject(s)
Epithelial Cells , Thymus Gland , Mice , Animals , Cell Differentiation , Homeostasis , Endoplasmic Reticulum
10.
Hum Brain Mapp ; 44(15): 5065-5078, 2023 10 15.
Article in English | MEDLINE | ID: mdl-37515386

ABSTRACT

Adopting highly sensitive multivariate electroencephalography (EEG) and alpha-band decoding analyses, the present study investigated proactive and reactive language control during bilingual language production. In a language-switching task, Chinese-English bilinguals were asked to name pictures based on visually presented cues. EEG and alpha-band decoding accuracy associated with switch and non-switch trials were used as indicators for inhibition over the non-target language. Multivariate EEG decoding analyses showed that the decoding accuracy in L1 but not in L2, was above chance level shortly after cue onset. In addition, alpha-band decoding results showed that the decoding accuracy in L1 rose above chance level in an early time window and a late time window locked to the stimulus. Together, these asymmetric patterns of decoding accuracy indicate that both proactive and reactive attentional control over the dominant L1 are exerted during bilingual word production, with a possibility of overlap between two control mechanisms. We addressed theoretical implications based on these findings for bilingual language control models.


Subject(s)
Multilingualism , Humans , Language , Electroencephalography , Attention/physiology , Cues , Evoked Potentials/physiology
11.
J Immunol ; 207(8): 2039-2050, 2021 10 15.
Article in English | MEDLINE | ID: mdl-34535574

ABSTRACT

Thymic epithelial cells (TECs) are critical for the development and generation of functionally competent T cells. Until now, the mechanism that regulates the survival of TECs is poorly understood. In the current study, we found that Tsc1 controls the homeostasis of medullary TECs (mTECs) by inhibiting lysosomal-mediated apoptosis pathway in mice. TEC-specific deletion of Tsc1 predominately decreased the cell number of mTECs and, to a lesser content, affected the development cortical TECs. The defect of mTECs caused by Tsc1 deficiency in mice impaired thymocyte development and peripheral T cell homeostasis. Mechanistically, Tsc1 deficiency did not affect the cell proliferation of mTECs but increased the apoptosis of mTECs significantly. RNA-sequencing analysis showed that pathways involved in lysosomal biogenesis, cell metabolism, and apoptosis were remarkably elevated in Tsc1-deficient mTECs compared with their wild-type counterparts. Tsc1-deficient mTECs exhibited overproduction of reactive oxygen species and malfunction of lysosome, with lysosome membrane permeabilization and the release of cathepsin B and cathepsin L to the cytosol, which then lead to Bid cleaved into active truncated Bid and subsequently intrinsic apoptosis. Finally, we showed that the impaired development of mTECs could be partially reversed by decreasing mTORC1 activity via haploinsufficiency of Raptor Thus, Tsc1 is essential for the homeostasis of mTECs by inhibiting lysosomal-mediated apoptosis through mTORC1-dependent pathways.


Subject(s)
Epithelial Cells/metabolism , Mechanistic Target of Rapamycin Complex 1/metabolism , Thymus Gland/cytology , Tuberous Sclerosis Complex 1 Protein/metabolism , Animals , Apoptosis , Cell Differentiation , Cell Proliferation , Cell Survival , Cells, Cultured , Epithelial Cells/cytology , Feedback, Physiological , Haploinsufficiency , Homeostasis , Mice , Mice, Knockout , Reactive Oxygen Species/metabolism , Regulatory-Associated Protein of mTOR/genetics , Tuberous Sclerosis Complex 1 Protein/genetics
12.
Cereb Cortex ; 33(1): 35-49, 2022 12 15.
Article in English | MEDLINE | ID: mdl-35226917

ABSTRACT

The cognitive function of the human cerebellum could be characterized as enigmatic. However, researchers have attempted to detail the comprehensive role of the cerebellum in several cognitive processes in recent years. Here, using functional magnetic resonance imaging (fMRI) and transcranial direct current stimulation (tDCS), we revealed different functions of bilateral cerebellar lobules in bilingual language production. Specifically, brain activation showed the bilateral posterolateral cerebellum was associated with bilingual language control, and an effective connectivity analysis built brain networks for the interaction between the cerebellum and the cerebral cortex. Furthermore, anodal tDCS over the right cerebellum significantly optimizes language control performance in bilinguals. Together, these results reveal a precise asymmetrical functional distribution of the cerebellum in bilingual language production, suggesting that the right cerebellum is more involved in language control. In contrast, its left counterpart undertakes a computational role in cognitive control function by connecting with more prefrontal, parietal, subcortical brain areas.


Subject(s)
Transcranial Direct Current Stimulation , Humans , Transcranial Direct Current Stimulation/methods , Cerebellum/diagnostic imaging , Cerebellum/physiology , Language , Cognition/physiology , Brain Mapping , Magnetic Resonance Imaging/methods
13.
J Neuroinflammation ; 19(1): 163, 2022 Jun 21.
Article in English | MEDLINE | ID: mdl-35729645

ABSTRACT

BACKGROUND: Hydrocephalus is a severe complication of intracerebral hemorrhage with ventricular extension (ICH-IVH) and causes cerebrospinal fluid (CSF) accumulation. The choroid plexus epithelium plays an important role in CSF secretion and constitutes the blood-CSF barrier within the brain-immune system interface. Although the NLRP3 inflammasome, as a key component of the innate immune system, promotes neuroinflammation, its role in the pathogenesis of hydrocephalus after hemorrhage has not been investigated. Therefore, this study aimed to investigate the potential mechanism of NLRP3 in hydrocephalus to discover a potential marker for targeted therapy. METHODS: A rat model of hydrocephalus after ICH-IVH was developed through autologous blood infusion in wild-type and Nlrp3-/- rats. By studying the features and processes of the model, we investigated the relationship between the NLRP3 inflammasome and CSF hypersecretion in the choroid plexus. RESULTS: The ICH-IVH model rats showed ventricular dilation accompanied by CSF hypersecretion for 3 days. Based on the choroid plexus RNA-seq and proteomics results, we found that an inflammatory response was activated. The NLRP3 inflammasome was investigated, and the expression levels of NLRP3 inflammasome components reached a peak at 3 days after ICH-IVH. Inhibition of NLRP3 by an MCC950 inflammasome inhibitor or Nlrp3 knockout decreased CSF secretion and ventricular dilation and attenuated neurological deficits after ICH-IVH. The mechanism underlying the neuroprotective effects of NLRP3 inhibition involved decreased phosphorylation of NKCC1, which is a major protein that regulates CSF secretion by altering Na+- and K+-coupled water transport, via MCC950 or Nlrp3 knockout. In combination with the in vitro experiments, this experiment confirmed the involvement of the NLRP3/p-NKCC1 pathway and Na+ and K+ flux. CONCLUSIONS: This study demonstrates that NKCC1 phosphorylation in the choroid plexus epithelium promotes NLRP3 inflammasome-mediated CSF hypersecretion and that NLRP3 plays an important role in the pathogenesis of hydrocephalus after hemorrhage. These findings provide a new therapeutic strategy for treating hydrocephalus.


Subject(s)
Choroid Plexus , Hydrocephalus , Animals , Cerebral Hemorrhage/pathology , Choroid Plexus/metabolism , Hydrocephalus/complications , Hydrocephalus/metabolism , Inflammasomes/metabolism , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , Rats , Solute Carrier Family 12, Member 2
14.
Bioorg Med Chem ; 68: 116880, 2022 08 15.
Article in English | MEDLINE | ID: mdl-35714535

ABSTRACT

l-Threonine aldolases (LTAs) employing pyridoxal phosphate (PLP) as cofactor can convert low-cost achiral substrates glycine and aldehyde directly into valuable ß-hydroxy-α-amino acids such as (2R,3S)-2-amino-3-hydroxy-3-(4-nitrophenyl) propanoic acid ((R,S)-AHNPA), which is utilized broadly as crucial chiral intermediates for bioactive compounds. However, LTAs' stereospecificity towards the ß carbon is rather moderate and their activity and stability at high substrate load is low, which limits their industrial application. Here, computer-aided directed evolution was applied to improve overall activity, selectivity and stability under desired process conditions of a l-threonine aldolase in the asymmetric synthesis of (R,S)-AHNPA. Selectivity and stability determining regions were computationally identified for structure-guided directed evolution of LTA-variants under efficient biocatalytic process conditions using 40% ethanol as cosolvent. We applied molecular modeling to rationalize selectivity improvement and design focused libraries targeting the substrate binding pocket, and we also used MD simulations in nonaqueous process environment as an effective and promising method to predict potential unstable loop regions near the tetramer interface which are hot-spots for cosolvent resistance. An excellent LTA variant EM-ALDO031 with 18 mutations was obtained, which showed âˆ¼ 30-fold stability improvement in 40% ethanol and diastereoselectivity (de) raised from 31.5% to 85% through a three-phase evolution campaign. Our fast and efficient data-driven methodology utilizing a combination of experimental and computational tools enabled us to evolve an aldolase variant to achieve the target of 90% conversion at up to 150 g/L substrate load in 40% ethanol, enabling the biocatalytic production of ß-hydroxy-α-amino acids from cheap achiral precursors at multi-ton scale.


Subject(s)
Chloramphenicol , Glycine Hydroxymethyltransferase , Amino Acids/chemistry , Computers , Ethanol , Glycine Hydroxymethyltransferase/chemistry , Glycine Hydroxymethyltransferase/genetics , Glycine Hydroxymethyltransferase/metabolism , Hydrolases/metabolism , Substrate Specificity
15.
Int J Mol Sci ; 24(1)2022 Dec 28.
Article in English | MEDLINE | ID: mdl-36613975

ABSTRACT

The fruit of Litchi chinensis contains high levels of proanthocyanidins (PAs) in the pericarp. These substances can serve as substrates of laccase-mediated rapid pericarp browning after the fruit is harvested. In this study, we found that the major PAs in litchi pericarp were (-)-epicatechin (EC) and several procyanidins (PCs), primarily PC A2, B2, and B1, and the EC and the PC content decreased with the development of the fruit. RNA-seq analysis showed that 43 early and late structure genes related to flavonoid/PA biosynthesis were expressed in the pericarp, including five ANTHOCYANIDIN REDUCTASE (ANR), two LEUCOANTHOCYANIDIN REDUCTASE (LAR), and two ANTHOCYANIDIN SYNTHASE (ANS) genes functioning in the PA biosynthesis branch of the flavonoid pathway. Among these nine PA biosynthesis-related genes, ANR1a, LAR1/2, and ANS1 were highly positively correlated with changes in the EC/PC content, suggesting that they are the key PA biosynthesis-related genes. Several transcription factor (TF) genes, including MYB, bHLH, WRKY, and AP2 family members, were found to be highly correlated with ANR1a, LAR1/2, and ANS1, and their relevant binding elements were detected in the promoters of these target genes, strongly suggesting that these TF genes may play regulatory roles in PA biosynthesis. In summary, this study identified the candidate key structure and regulatory genes in PA biosynthesis in litchi pericarp, which will assist in understanding the accumulation of high levels of browning-related PA substances in the pericarp.


Subject(s)
Litchi , Proanthocyanidins , Fruit/metabolism , Proanthocyanidins/metabolism , Litchi/chemistry , Transcriptome , Flavonoids/metabolism , Oxidoreductases/metabolism , Plant Proteins/metabolism , Gene Expression Regulation, Plant
16.
Int J Mol Sci ; 23(19)2022 Oct 03.
Article in English | MEDLINE | ID: mdl-36233017

ABSTRACT

Recent studies have confirmed that chlorophyllase (CLH), a long-found chlorophyll (Chl) dephytylation enzyme for initiating Chl catabolism, has no function in leaf senescence-related Chl breakdown. Yet, CLH is considered to be involved in fruit degreening and responds to external and hormonal stimuli. The purpose of this work was to elucidate in detail the biochemical, structural properties, and gene expression of four CLHs from the Solanum lycopersicum genome so as to understand the roles of Solanum lycopersicum chlorophyllases (SlCLHs). SlCLH1/4 were the predominantly expressed CLH genes during leaf and fruit development/ripening stages, and SlCLH1 in mature green fruit was modulated by light. SlCLH1/2/3/4 contained a highly conserved GHSXG lipase motif and a Ser-Asp-His catalytic triad. We identified Ser159, Asp226, and His258 as the essential catalytic triad by site-directed mutagenesis in recombinant SlCLH1. Kinetic analysis of the recombinant enzymes revealed that SlCLH1 had high hydrolysis activities against Chl a, Chl b, and pheophytin a (Phein a), but preferred Chl a and Chl b over Phein a; SlCLH2/3 only showed very low activity to Chl a and Chl b, while SlCLH4 showed no Chl dephytylation activity. The recombinant SlCLH1/2/3 had different pH stability and temperature optimum. Removal of the predicted N-terminal processing peptide caused a partial loss of activity in recombinant SlCLH1/2 but did not compromise SlCLH3 activity. These different characteristics among SlCLHs imply that they may have different physiological functions in tomato.


Subject(s)
Solanum lycopersicum , Carboxylic Ester Hydrolases , Chlorophyll/metabolism , Gene Expression Regulation, Plant , Kinetics , Lipase/metabolism , Solanum lycopersicum/metabolism
17.
J Cell Physiol ; 236(6): 4725-4737, 2021 06.
Article in English | MEDLINE | ID: mdl-33269476

ABSTRACT

The differentiation of mature medullary thymic epithelial cells (mTECs) is critical for the induction of central immune tolerance. Although the critical effect of mechanistic target of rapamycin complex 1 (mTORC1) in shaping mTEC differentiation has been studied, the regulatory role of mTORC2 in the differentiation and maturation of mTECs is poorly understood. We herein reported that TEC-specific ablation of a rapamycin-insensitive companion of mTOR (RICTOR), a key component of mTORC2, significantly decreased the thymus size and weight, the total cell number of TECs, and the cell number of mTECs with a smaller degree of reduced cortical thymic epithelial cells. Interestingly, RICTOR deficiency significantly accelerated the mTEC maturation process, as indicated by the increased ratios of mature mTECs (MHCIIhi , CD80+ , and Aire+ ) to immature mTECs (MHCIIlo , CD80- , and Aire- ) in Rictor-deficient mice. The RNA-sequencing assays showed that the upregulated nuclear factor-κB (NF-κB) signaling pathway in Rictor-deficient mTECs was one of the obviously altered pathways compared with wild-type mTECs. Our studies further showed that Rictor-deficient mTECs exhibited upregulated expression of receptor activator of NF-κB (RANK) and lymphotoxin ß receptor (LTßR), as well as increased activity of canonical and noncanonical NF-κB signaling pathways as determined by ImageStream and Simple Western. Finally, our results showed that inhibition of NF-κB signaling pathways could partially reverse the accelerated maturation of mTECs in Rictor conditional KO mice. Thus, mTORC2 negatively controls the kinetics of the mTEC maturation process by inhibiting the LTßR/RANK-NF-κB signal axis.


Subject(s)
Cell Differentiation , Epithelial Cells/enzymology , Lymphotoxin beta Receptor/metabolism , Mechanistic Target of Rapamycin Complex 2/metabolism , NF-kappa B/metabolism , Rapamycin-Insensitive Companion of mTOR Protein/metabolism , Receptor Activator of Nuclear Factor-kappa B/metabolism , Thymus Gland/enzymology , Animals , Epithelial Cells/pathology , Gene Expression Regulation , Kinetics , Lymphotoxin beta Receptor/genetics , Mechanistic Target of Rapamycin Complex 2/genetics , Mice, Knockout , Rapamycin-Insensitive Companion of mTOR Protein/genetics , Receptor Activator of Nuclear Factor-kappa B/genetics , Signal Transduction , Thymocytes/enzymology , Thymocytes/pathology , Thymus Gland/pathology
18.
Invest New Drugs ; 38(4): 1031-1043, 2020 08.
Article in English | MEDLINE | ID: mdl-31758360

ABSTRACT

Chemotherapy has always been the first therapeutic option for patients with advanced non-small cell lung cancer (NSCLC) with untreatable oncogenic mutations. However, chemotherapy has demonstrated limited success and is associated with severe side effects. This research aimed to investigate the antitumor efficacy and cytotoxic safety of the conjugate ZHER2:V2-pemetrexed, a novel targeted chemotherapeutic drug. In this context, human epidermal growth factor receptor 2 (HER2) + A549 lung xenografts were treated using ZHER2:V2-pemetrexed, pemetrexed or physiological saline. Therapeutic efficacy was monitored by single photon emission computed tomography (SPECT) imaging using the 99mTc-labeled ZHER2:V2-pemetrexed conjugate and further confirmed by performing apoptosis assays using flow cytometry analysis and hematoxylin-eosin (H&E) staining. To evaluate the expression of HER2 in tumor tissues, immunohistochemistry was performed, accompanied by quantitative analysis using flow cytometry. A toxicological evaluation was also conducted. Imaging with 99mTc-ZHER2:V2-pemetrexed demonstrated that in HER2+ A549 models, ZHER2:V2-pemetrexed showed better antineoplastic effects than pemetrexed. Compared with pemetrexed, the results from the pathological and flow cytometry analyses also revealed that ZHER2:V2-pemetrexed exhibits high antitumor activity against A549 tumors, inducing necrosis, apoptosis and cell cycle arrest. In addition, the clinical signs of toxicity in the ZHER2:V2-pemetrexed treated group were reduced compared with those in the pemetrexed treated group. These data revealed that the ZHER2:V2-pemetrexed conjugate encompasses promising targeted antitumor activity against HER2-positive lung adenocarcinoma, with reduced side effects compared with pemetrexed. Thus, the ZHER2:V2-pemetrexed conjugate may serve as a novel molecular agent with tremendous clinical breakthrough potential in the diagnosis and treatment of HER2-positive lung adenocarcinoma.


Subject(s)
Adenocarcinoma of Lung/drug therapy , Antineoplastic Agents/therapeutic use , Lung Neoplasms/drug therapy , Pemetrexed/therapeutic use , Receptor, ErbB-2/genetics , Recombinant Fusion Proteins/therapeutic use , A549 Cells , Adenocarcinoma of Lung/diagnostic imaging , Adenocarcinoma of Lung/pathology , Animals , Apoptosis/drug effects , Cell Cycle Checkpoints/drug effects , Female , Humans , Lung Neoplasms/diagnostic imaging , Lung Neoplasms/pathology , Mice, Inbred BALB C , Mice, Nude , Tomography, Emission-Computed, Single-Photon , Tumor Burden/drug effects , Xenograft Model Antitumor Assays
19.
Eur J Nucl Med Mol Imaging ; 47(5): 1137-1146, 2020 05.
Article in English | MEDLINE | ID: mdl-31728587

ABSTRACT

PURPOSE: To assess the predictive power of pre-therapy 18F-FDG PET/CT-based radiomic features for epidermal growth factor receptor (EGFR) mutation status in non-small cell lung cancer. METHODS: Two hundred and forty-eight lung cancer patients underwent pre-therapy diagnostic 18F-FDG PET/CT scans and were tested for genetic mutations. The LIFEx package was used to extract 47 PET and 45 CT radiomic features reflecting tumor heterogeneity and phenotype. The least absolute shrinkage and selection operator (LASSO) algorithm was used to select radiomic features and develop a radiomics signature. We compared the predictive performance of models established by radiomics signature, clinical variables, and their combinations using receiver operating curves (ROCs). In addition, a nomogram based on the radiomics signature score (rad-score) and clinical variables was developed. RESULTS: The patients were divided into a training set (n = 175) and a validation set (n = 73). Ten radiomic features were selected to build the radiomics signature model. The model showed a significant ability to discriminate between EGFR mutation and EGFR wild type, with area under the ROC curve (AUC) equal to 0.79 in the training set, and 0.85 in the validation set, compared with 0.75 and 0.69 for the clinical model. When clinical variables and radiomics signature were combined, the AUC increased to 0.86 (95% CI [0.80-0.91]) in the training set and 0.87 (95% CI [0.79-0.95]) in the validation set, thus showing better performance in the prediction of EGFR mutations. CONCLUSION: The PET/CT-based radiomic features showed good performance in predicting EGFR mutation in non-small cell lung cancer, providing a useful method for the choice of targeted therapy in a clinical setting.


Subject(s)
Carcinoma, Non-Small-Cell Lung , Lung Neoplasms , Carcinoma, Non-Small-Cell Lung/diagnostic imaging , Carcinoma, Non-Small-Cell Lung/genetics , ErbB Receptors/genetics , Fluorodeoxyglucose F18 , Humans , Lung Neoplasms/diagnostic imaging , Lung Neoplasms/genetics , Mutation , Positron Emission Tomography Computed Tomography
20.
Neuroimage ; 199: 454-465, 2019 10 01.
Article in English | MEDLINE | ID: mdl-31200066

ABSTRACT

For bilinguals, language control is needed for selecting the target language during language production. Numerous studies have examined the neural correlates of language control and shown a close relationship between language control and domain-general cognitive control. However, it remains unknown how these brain regions coordinate with each other when bilinguals exert cognitive control over linguistic and nonlinguistic representations. We addressed this gap using an extended unified structural equation modeling (euSEM) approach. Sixty-five Chinese-English bilinguals performed language switching and nonverbal switching tasks during functional magnetic resonance imaging (fMRI) scanning. The results showed that language control was served by a cooperative brain network, including the frontal lobe, the parietal cortex, subcortical areas, and the cerebellum. More importantly, we found that language control recruited more subcortical areas and connections from frontal to subcortical areas compared with domain-general cognitive control, demonstrating a reconfigurable brain network. In addition, the reconfiguration efficiency of the brain network was mainly determined by general cognitive ability but was also mediated by second language (L2) proficiency. These findings provide the first data-driven connectivity model that specifies the brain network for language control in bilinguals and also shed light on the relationship between language control and domain-general cognitive control.


Subject(s)
Brain/physiology , Connectome/methods , Executive Function/physiology , Multilingualism , Nerve Net/physiology , Adult , Brain/diagnostic imaging , Female , Humans , Magnetic Resonance Imaging , Male , Psycholinguistics , Young Adult
SELECTION OF CITATIONS
SEARCH DETAIL