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1.
Arterioscler Thromb Vasc Biol ; 43(7): 1219-1233, 2023 07.
Article in English | MEDLINE | ID: mdl-37165876

ABSTRACT

BACKGROUND: Lower plasma levels of LDL (low-density lipoprotein) cholesterol (LDL-C) can reduce the risk of atherosclerotic cardiovascular disease. The loss-of-function mutations in PCSK9 (proprotein convertase subtilisin/kexin type 9) have been known to associate with low LDL-C in many human populations. PCSK9 genetic variants in Chinese Uyghurs who are at high risk of atherosclerotic cardiovascular disease due to their dietary habits have not been reported. METHODS: The study involved the whole-exome and target sequencing of college students from Uyghur and other ethnic groups in Xinjiang, China, for the association of PCSK9 loss-of-function mutations with low plasma levels of LDL-C. The mechanisms by which the identified mutations affect the function of PCSK9 were investigated in cultured cells using biochemical and cell assays. The causal effects of the identified PCSK9 mutations on LDL-C levels were verified in mice injected with adeno-associated virus expressing different forms of PCSK9 and fed a high-cholesterol diet. RESULTS: We identified 2 PCSK9 mutations-E144K and C378W-in Chinese Uyghurs with low plasma levels of LDL-C. The E144K and C378W mutations impaired the maturation and secretion of the PCSK9 protein, respectively. Adeno-associated virus-mediated expression of E144K and C378W mutants in Pcsk9 KO (knockout) mice fed a high-cholesterol diet also hampered PCSK9 secretion into the serum, resulting in elevated levels of LDL receptor in the liver and reduced levels of LDL-C in the serum. CONCLUSIONS: Our study shows that E144K and C378W are PCSK9 loss-of-function mutations causing low LDL-C levels in mice and probably in humans as well.


Subject(s)
Atherosclerosis , Cardiovascular Diseases , Hypercholesterolemia , Humans , Mice , Animals , Proprotein Convertase 9/genetics , Cholesterol, LDL , Serine Endopeptidases/genetics , Proprotein Convertases/genetics , Proprotein Convertases/metabolism , Receptors, LDL/genetics , Receptors, LDL/metabolism , Mice, Knockout , Atherosclerosis/genetics , Atherosclerosis/prevention & control , Atherosclerosis/metabolism , Mutation
2.
Front Plant Sci ; 14: 1162372, 2023.
Article in English | MEDLINE | ID: mdl-37051084

ABSTRACT

Cadmium (Cd) pollution seriously reduces the yield and quality of vegetables. Reducing Cd accumulation in vegetables is of great significance for improving food safety and sustainable agricultural development. Here, using tomato as the material, we analyzed the effect of foliar spraying with zinc oxide nanoparticles (ZnO NPs) on Cd accumulation and tolerance in tomato seedlings. Foliar spraying with ZnO NPs improved Cd tolerance by increasing photosynthesis efficiency and antioxidative capacity, while it reduced Cd accumulation by 40.2% in roots and 34.5% in leaves but increased Zn content by 33.9% in roots and 78.6% in leaves. Foliar spraying with ZnO NPs also increased the contents of copper (Cu) and manganese (Mn) in the leaves of Cd-treated tomato seedlings. Subsequent metabonomic analysis showed that ZnO NPs exposure alleviated the fluctuation of metabolic profiling in response to Cd toxicity, and it had a more prominent effect in leaves than in roots. Correlation analysis revealed that several differentially accumulated metabolites were positively or negatively correlated with the growth parameters and physiol-biochemical indexes. We also found that flavonoids and alkaloid metabolites may play an important role in ZnO NP-alleviated Cd toxicity in tomato seedlings. Taken together, the results of this study indicated that foliar spraying with ZnO NPs effectively reduced Cd accumulation in tomato seedlings; moreover, it also reduced oxidative damage, improved the absorption of trace elements, and reduced the metabolic fluctuation caused by Cd toxicity, thus alleviating Cd-induced growth inhibition in tomato seedlings. This study will enable us to better understand how ZnO NPs regulate plant growth and development and provide new insights into the use of ZnO NPs for improving growth and reducing Cd accumulation in vegetables.

4.
Environ Int ; 170: 107646, 2022 12.
Article in English | MEDLINE | ID: mdl-36410239

ABSTRACT

Perfluorobutane sulfonate (PFBS) has oily and hydrophobic characteristics similar to those of perfluorooctane sulfonic acid (PFOS), which is an environmental organic pollutant and has gradually become the main substitute for PFOS in industry. Several studies have revealed the potential toxicity of PFBS in animals. PFBS can be taken up and accumulate in plants; however, whether and how PFBS affects plant growth remain largely unclear. A low concentration of PFBS did not affect plant growth, indicating that it had higher environmental safety than other perfluorinated compounds; however, a high concentration of PFBS (>1 mM) markedly inhibited primary root growth in Arabidopsis thaliana. Subsequently, we investigated the molecular mechanisms underlying plant growth mediated by high concentrations of PFBS. First, a genome-wide transcriptomic analysis revealed that PFBS altered the expression of genes associated with phytohormone signaling pathways. Combining physio-biochemical and genetic analyses, we next demonstrated that PFBS reduced the contents of indole-3-acetic acid (IAA) and abscisic acid (ABA), and disrupted the two signaling pathways in plants, finally inhibiting root growth. Moreover, a high concentration of PFBS also inhibited photosynthesis by comprehensively repressing the expression of genes related to the Calvin cycle and the photosynthetic apparatus. Such an understanding is helpful for elucidating the phytotoxicity of PFBS and provides a new strategy for toxicology research on organic pollutants in plants.


Subject(s)
Plants , Plants/metabolism
5.
Sci Total Environ ; 851(Pt 2): 158287, 2022 Dec 10.
Article in English | MEDLINE | ID: mdl-36030856

ABSTRACT

Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) are the most representative perfluoroalkyl substances that accumulate in the food chain and are harmful to the environment. The uptake, translocation and physiological effects of PFOA and PFOS in plants have been reported in recent years; however, the regulatory mechanisms underlying PFOA- and PFOS-mediated plant growth and development remain largely unclear. Here, using Arabidopsis thaliana as the study material, we showed that both PFOA and PFOS inhibited plant growth; PFOS showed a stronger inhibitory effect on primary root (PR) growth, whereas PFOA exerted a stronger inhibitory effect on photosynthesis. Transcriptome analysis revealed that PFOA- and PFOS-modulated plant growth and development were correlated with the phytohormones auxin and abscisic acid (ABA). Further genetic analyses using mutants related to auxin biosynthesis, receptors and transport and mutants related to ABA biosynthesis and signalling transduction revealed that both PFOA and PFOS inhibited PR growth by modulating auxin biosynthesis and signalling pathways, and the ABA signalling pathway was also involved in PFOS-mediated PR growth inhibition. Collectively, these results shed new light on the molecular mechanisms of PFOA- and PFOS-mediated root system growth and their effects on phytohormone signalling pathways in plants.


Subject(s)
Alkanesulfonic Acids , Arabidopsis , Fluorocarbons , Fluorocarbons/toxicity , Plant Growth Regulators/pharmacology , Arabidopsis/genetics , Abscisic Acid/pharmacology , Alkanesulfonic Acids/toxicity , Caprylates/toxicity , Plants , Indoleacetic Acids/pharmacology
6.
Nature ; 608(7922): 413-420, 2022 08.
Article in English | MEDLINE | ID: mdl-35922515

ABSTRACT

High cholesterol is a major risk factor for cardiovascular disease1. Currently, no drug lowers cholesterol through directly promoting cholesterol excretion. Human genetic studies have identified that the loss-of-function Asialoglycoprotein receptor 1 (ASGR1) variants associate with low cholesterol and a reduced risk of cardiovascular disease2. ASGR1 is exclusively expressed in liver and mediates internalization and lysosomal degradation of blood asialoglycoproteins3. The mechanism by which ASGR1 affects cholesterol metabolism is unknown. Here, we find that Asgr1 deficiency decreases lipid levels in serum and liver by stabilizing LXRα. LXRα upregulates ABCA1 and ABCG5/G8, which promotes cholesterol transport to high-density lipoprotein and excretion to bile and faeces4, respectively. ASGR1 deficiency blocks endocytosis and lysosomal degradation of glycoproteins, reduces amino-acid levels in lysosomes, and thereby inhibits mTORC1 and activates AMPK. On one hand, AMPK increases LXRα by decreasing its ubiquitin ligases BRCA1/BARD1. On the other hand, AMPK suppresses SREBP1 that controls lipogenesis. Anti-ASGR1 neutralizing antibody lowers lipid levels by increasing cholesterol excretion, and shows synergistic beneficial effects with atorvastatin or ezetimibe, two widely used hypocholesterolaemic drugs. In summary, this study demonstrates that targeting ASGR1 upregulates LXRα, ABCA1 and ABCG5/G8, inhibits SREBP1 and lipogenesis, and therefore promotes cholesterol excretion and decreases lipid levels.


Subject(s)
Asialoglycoprotein Receptor , Cholesterol , Lipid Metabolism , AMP-Activated Protein Kinases/metabolism , ATP Binding Cassette Transporter 1 , ATP Binding Cassette Transporter, Subfamily G, Member 5 , ATP Binding Cassette Transporter, Subfamily G, Member 8 , Asialoglycoprotein Receptor/antagonists & inhibitors , Asialoglycoprotein Receptor/deficiency , Asialoglycoprotein Receptor/genetics , Asialoglycoprotein Receptor/metabolism , Asialoglycoproteins/metabolism , Atorvastatin/pharmacology , BRCA1 Protein , Cardiovascular Diseases/genetics , Cardiovascular Diseases/metabolism , Cholesterol/metabolism , Drug Synergism , Endocytosis , Ezetimibe/pharmacology , Humans , Lipids/analysis , Lipids/blood , Liver/metabolism , Liver X Receptors/metabolism , Lysosomes/metabolism , Mechanistic Target of Rapamycin Complex 1/antagonists & inhibitors , Sterol Regulatory Element Binding Protein 1 , Ubiquitin-Protein Ligases/metabolism
7.
iScience ; 24(11): 103228, 2021 Nov 19.
Article in English | MEDLINE | ID: mdl-34746697

ABSTRACT

Crosstalk among ABA, auxin, and ROS plays critical roles in modulating seed germination, root growth, and suberization. However, the underlying molecular mechanisms remain largely elusive. Here, MYB70, a R2R3-MYB transcription factor was shown to be a key component of these processes in Arabidopsis thaliana. myb70 seeds displayed decreased sensitivity, while MYB70-overexpressing OX70 seeds showed increased sensitivity in germination in response to exogenous ABA through MYB70 physical interaction with ABI5 protein, leading to enhanced stabilization of ABI5. Furthermore, MYB70 modulates root system development (RSA) which is associated with increased conjugated IAA content and H2O2/O2 ⋅- ratio but reduced root suberin deposition, consequently affecting nutrient uptake. In support of these data, MYB70 positively regulates the expression of auxin conjugation-related GH3, while negatively peroxidase-encoding and suberin biosynthesis-related genes. Our findings collectively revealed a previously uncharacterized component that modulates ABA and auxin signaling pathways, H2O2/O2 ⋅- balance, and suberization, consequently regulating RSA and seed germination.

8.
Protein Cell ; 12(4): 279-296, 2021 04.
Article in English | MEDLINE | ID: mdl-32666500

ABSTRACT

Sterol-regulatory element binding proteins (SREBPs) are the key transcriptional regulators of lipid metabolism. The activation of SREBP requires translocation of the SREBP precursor from the endoplasmic reticulum to the Golgi, where it is sequentially cleaved by site-1 protease (S1P) and site-2 protease and releases a nuclear form to modulate gene expression. To search for new genes regulating cholesterol metabolism, we perform a genome-wide CRISPR/Cas9 knockout screen and find that partner of site-1 protease (POST1), encoded by C12ORF49, is critically involved in the SREBP signaling. Ablation of POST1 decreases the generation of nuclear SREBP and reduces the expression of SREBP target genes. POST1 binds S1P, which is synthesized as an inactive protease (form A) and becomes fully mature via a two-step autocatalytic process involving forms B'/B and C'/C. POST1 promotes the generation of the functional S1P-C'/C from S1P-B'/B (canonical cleavage) and, notably, from S1P-A directly (non-canonical cleavage) as well. This POST1-mediated S1P activation is also essential for the cleavages of other S1P substrates including ATF6, CREB3 family members and the α/ß-subunit precursor of N-acetylglucosamine-1-phosphotransferase. Together, we demonstrate that POST1 is a cofactor controlling S1P maturation and plays important roles in lipid homeostasis, unfolded protein response, lipoprotein metabolism and lysosome biogenesis.


Subject(s)
Membrane Proteins/metabolism , Signal Transduction , Sterol Regulatory Element Binding Proteins/metabolism , CRISPR-Cas Systems , HeLa Cells , Humans , Lipoproteins/biosynthesis , Lipoproteins/genetics , Lysosomes/genetics , Lysosomes/metabolism , Membrane Proteins/genetics , Sterol Regulatory Element Binding Proteins/genetics
9.
J Biol Chem ; 296: 100032, 2021.
Article in English | MEDLINE | ID: mdl-33154164

ABSTRACT

Inducible degrader of the low-density lipoprotein receptor (IDOL) is an E3 ubiquitin ligase mediating degradation of low-density lipoprotein (LDL) receptor (LDLR). IDOL also controls its own stability through autoubiquitination, primarily at lysine 293. Whether IDOL may undergo other forms of posttranslational modification is unknown. In this study, we show that IDOL can be modified by small ubiquitin-like modifier 1 at the K293 residue at least. The SUMOylation of IDOL counteracts its ubiquitination and augments IDOL protein levels. SUMOylation and the associated increase of IDOL protein are effectively reversed by SUMO-specific peptidase 1 (SENP1) in an activity-dependent manner. We further demonstrate that SENP1 affects LDLR protein levels by modulating IDOL. Overexpression of SENP1 increases LDLR protein levels and enhances LDL uptake in cultured cells. On the contrary, loss of SENP1 lowers LDLR levels in an IDOL-dependent manner and reduces LDL endocytosis. Collectively, our results reveal SUMOylation as a new regulatory posttranslational modification of IDOL and suggest that SENP1 positively regulates the LDLR pathway via deSUMOylation of IDOL and may therefore be exploited for the treatment of cardiovascular disease.


Subject(s)
Cysteine Endopeptidases/metabolism , Receptors, LDL/metabolism , Ubiquitin-Protein Ligases/metabolism , Cell Line , Humans , Protein Processing, Post-Translational , Sumoylation , Ubiquitination
10.
Nature ; 588(7838): 479-484, 2020 12.
Article in English | MEDLINE | ID: mdl-33177714

ABSTRACT

Cholesterol is an essential lipid and its synthesis is nutritionally and energetically costly1,2. In mammals, cholesterol biosynthesis increases after feeding and is inhibited under fasting conditions3. However, the regulatory mechanisms of cholesterol biosynthesis at the fasting-feeding transition remain poorly understood. Here we show that the deubiquitylase ubiquitin-specific peptidase 20 (USP20) stabilizes HMG-CoA reductase (HMGCR), the rate-limiting enzyme in the cholesterol biosynthetic pathway, in the feeding state. The post-prandial increase in insulin and glucose concentration stimulates mTORC1 to phosphorylate USP20 at S132 and S134; USP20 is recruited to the HMGCR complex and antagonizes its degradation. The feeding-induced stabilization of HMGCR is abolished in mice with liver-specific Usp20 deletion and in USP20(S132A/S134A) knock-in mice. Genetic deletion or pharmacological inhibition of USP20 markedly decreases diet-induced body weight gain, reduces lipid levels in the serum and liver, improves insulin sensitivity and increases energy expenditure. These metabolic changes are reversed by expression of the constitutively stable HMGCR(K248R). This study reveals an unexpected regulatory axis from mTORC1 to HMGCR via USP20 phosphorylation and suggests that inhibitors of USP20 could be used to lower cholesterol levels to treat metabolic diseases including hyperlipidaemia, liver steatosis, obesity and diabetes.


Subject(s)
Cholesterol/biosynthesis , Eating/physiology , Hydroxymethylglutaryl CoA Reductases/metabolism , Mechanistic Target of Rapamycin Complex 1/metabolism , Ubiquitin Thiolesterase/metabolism , Animals , Cell Line , Glucose/metabolism , Humans , Insulin/metabolism , Liver/metabolism , Male , Metabolic Diseases/genetics , Metabolic Diseases/metabolism , Metabolism/genetics , Mice , Mice, Inbred C57BL , Phosphorylation , Phosphoserine/metabolism , Ubiquitin Thiolesterase/antagonists & inhibitors , Ubiquitin Thiolesterase/chemistry , Ubiquitin Thiolesterase/deficiency , Ubiquitination , Weight Gain
11.
PLoS Genet ; 16(8): e1008955, 2020 08.
Article in English | MEDLINE | ID: mdl-32776921

ABSTRACT

Non-alcoholic fatty liver disease (NAFLD) is a metabolic disorder characterized by excess lipid accumulation in the liver without significant consumption of alcohol. The transmembrane 6 superfamily member 2 (TM6SF2) E167K missense variant strongly associates with NAFLD in humans. The E167K mutation destabilizes TM6SF2, resulting in hepatic lipid accumulation and low serum lipid levels. However, the molecular mechanism by which TM6SF2 regulates lipid metabolism remains unclear. By using tandem affinity purification in combination with mass spectrometry, we found that apolipoprotein B (APOB), ER lipid raft protein (ERLIN) 1 and 2 were TM6SF2-interacting proteins. ERLINs and TM6SF2 mutually bound and stabilized each other. TM6SF2 bound and stabilized APOB via two luminal loops. ERLINs did not interact with APOB directly but still increased APOB stability through stabilizing TM6SF2. This APOB stabilization was hampered by the E167K mutation that reduced the protein expression of TM6SF2. In mice, knockout of Tm6sf2 and knockdown of Tm6sf2 or Erlins decreased hepatic APOB protein level, causing lipid accumulation in the liver and lowering lipid levels in the serum. We conclude that defective APOB stabilization, as a result of ERLINs or TM6SF2 deficiency or E167K mutation, is a key factor contributing to NAFLD.


Subject(s)
Apolipoprotein B-100/genetics , Membrane Proteins/genetics , Nerve Tissue Proteins/genetics , Non-alcoholic Fatty Liver Disease/genetics , Animals , Cholesterol/genetics , Cholesterol/metabolism , Genetic Predisposition to Disease , Genotype , Humans , Immunoprecipitation , Lipid Metabolism/genetics , Lipids/blood , Lipids/genetics , Mice , Mice, Knockout , Multiprotein Complexes/genetics , Non-alcoholic Fatty Liver Disease/blood , Non-alcoholic Fatty Liver Disease/metabolism , Non-alcoholic Fatty Liver Disease/pathology , Polymorphism, Single Nucleotide/genetics , Protein Binding/genetics , Transfection
12.
Plant Cell Environ ; 43(8): 1925-1943, 2020 08.
Article in English | MEDLINE | ID: mdl-32406163

ABSTRACT

Salt stress activates defence responses in plants, including changes in leaf surface structure. Here, we showed that the transcriptional activation of cutin deposition and antioxidant defence by the R2R3-type MYB transcription factor AtMYB49 contributed to salt tolerance in Arabidopsis thaliana. Characterization of loss-of-function myb49 mutants, and chimeric AtMYB49-SRDX-overexpressing SRDX49 transcriptional repressor and AtMYB49-overexpressing (OX49) overexpressor plants demonstrated a positive role of AtMYB49 in salt tolerance. Transcriptome analysis revealed that many genes belonging to the category "cutin, suberin and wax biosyntheses" were markedly up-regulated and down-regulated in OX49 and SRDX49 plants, respectively, under normal and/or salt stress conditions. Some of these differentially expressed genes, including MYB41, ASFT, FACT and CYP86B1, were also shown to be the direct targets of AtMYB49 and activated by AtMYB49. Biochemical analysis indicated that AtMYB49 modulated cutin deposition in the leaves. Importantly, cuticular transpiration, chlorophyll leaching and toluidine blue-staining assays revealed a link between increased AtMYB49-mediated cutin deposition in leaves and enhanced salt tolerance. Additionally, increased AtMYB49 expression elevated Ca2+ level in leaves and improved antioxidant capacity by up-regulating genes encoding peroxidases and late embryogenesis abundant proteins. These results suggest that genetic manipulation of AtMYB49 may provide a novel way to improve salt tolerance in plants.


Subject(s)
Arabidopsis Proteins/metabolism , Arabidopsis/physiology , Salt Tolerance/physiology , Transcription Factors, General/metabolism , Antioxidants/metabolism , Arabidopsis Proteins/genetics , Gene Expression Regulation, Plant , Hydrogen Peroxide/metabolism , Lipids/physiology , Membrane Lipids/biosynthesis , Plant Leaves/metabolism , Plant Roots/metabolism , Plant Stomata/physiology , Plants, Genetically Modified , Seeds/metabolism , Seeds/ultrastructure , Transcription Factors, General/genetics
13.
Environ Sci Technol ; 54(7): 4409-4420, 2020 04 07.
Article in English | MEDLINE | ID: mdl-32182044

ABSTRACT

Carbon-based nanomaterials have potential applications in nanoenabled agriculture. However, the physiological and molecular mechanisms underlying single-walled carbon nanohorn (SWCNH)-mediated plant growth remain unclear. Here, we investigated the effects of SWCNHs on Arabidopsis grown in 1/4-strength Murashige and Skoog medium via physiological, genetic, and molecular analyses. Treatment with 0.1 mg/L SWCNHs promoted primary root (PR) growth and lateral root (LR) formation; 50 and 100 mg/L SWCNHs inhibited PR growth. Treatment with 0.1 mg/L SWCNHs increased the lengths of the meristematic and elongation zones, and transcriptomic and genetic analyses confirmed the positive effects of SWCNHs on root tip stem cell niche activity and meristematic cell division potential. Increased expression of YUC3 and YUC5 and increased PIN2 abundance improved PR growth and LR development in 0.1 mg/L SWCNH-treated seedlings. Metabolomic analyses revealed that SWCNHs altered the levels of sugars, amino acids, and organic acids, suggesting that SWCNHs reprogrammed carbon/nitrogen metabolism in plants. SWCNHs also regulate plant growth and development by increasing the levels of several secondary metabolites; transcriptomic analyses further supported these results. The present results are valuable for continued use of SWCNHs in agri-nanotechnology, and these molecular approaches could serve as examples for studies on the effects of nanomaterials in plants.


Subject(s)
Arabidopsis Proteins , Arabidopsis , Carbon , Cytochrome P-450 Enzyme System , Gene Expression Profiling , Indoleacetic Acids , Plant Roots , Seedlings , Transcriptome
14.
Environ Sci Technol ; 53(8): 4235-4244, 2019 04 16.
Article in English | MEDLINE | ID: mdl-30871319

ABSTRACT

Zinc oxide (ZnO) nanoparticles (nZnO) are among the most commonly used nanoparticles (NPs), and they have been shown to have harmful effects on plants. However, the molecular mechanisms underlying nZnO tolerance and root sensing of NP stresses have not been elucidated. Here, we compared the differential toxic effects of nZnO and Zn2+ toxicity on plants during exposure and recovery using a combination of transcriptomic and physiological analyses. Although both nZnO and Zn2+ inhibited primary root (PR) growth, nZnO had a stronger inhibitory effect on the growth of elongation zones, whereas Zn2+ toxicity had a stronger toxic effect on meristem cells. Timely recovery from stresses is critical for plant survival. Despite the stronger inhibitory effect of nZnO on PR growth, nZnO-exposed plants recovered from stress more rapidly than Zn2+-exposed plants upon transfer to normal conditions, and transcriptome data supported these results. In contrast to Zn2+ toxicity, nZnO induced endocytosis and caused microfilament rearrangement in the epidermal cells of elongation zones, thereby repressing PR growth. nZnO also repressed PR growth by disrupting cell wall organization and structure through both physical interactions and transcriptional regulation. The present study provides new insight into the comprehensive understanding and re-evaluation of NP toxicity in plants.


Subject(s)
Nanoparticles , Zinc Oxide , Transcriptome
15.
Plant Physiol ; 180(1): 529-542, 2019 05.
Article in English | MEDLINE | ID: mdl-30782964

ABSTRACT

Abscisic acid (ABA) reduces accumulation of potentially toxic cadmium (Cd) in plants. How the ABA signal is transmitted to modulate Cd uptake remains largely unclear. Here, we report that the basic region/Leu zipper transcription factor ABSCISIC ACID-INSENSITIVE5 (ABI5), a central ABA signaling molecule, is involved in ABA-repressed Cd accumulation in plants by physically interacting with a previously uncharacterized R2R3-type MYB transcription factor, MYB49. Overexpression of the Cd-induced MYB49 gene in Arabidopsis (Arabidopsis thaliana) resulted in a significant increase in Cd accumulation, whereas myb49 knockout plants and plants expressing chimeric repressors of MYB49:ERF-associated amphiphilic repression motif repression domain (SRDX49) exhibited reduced accumulation of Cd. Further investigations revealed that MYB49 positively regulates the expression of the basic helix-loop-helix transcription factors bHLH38 and bHLH101 by directly binding to their promoters, leading to activation of IRON-REGULATED TRANSPORTER1, which encodes a metal transporter involved in Cd uptake. MYB49 also binds to the promoter regions of the heavy metal-associated isoprenylated plant proteins (HIPP22) and HIPP44, resulting in up-regulation of their expression and subsequent Cd accumulation. On the other hand, as a feedback mechanism to control Cd uptake and accumulation in plant cells, Cd-induced ABA up-regulates the expression of ABI5, whose protein product interacts with MYB49 and prevents its binding to the promoters of downstream genes, thereby reducing Cd accumulation. Our results provide new insights into the molecular feedback mechanisms underlying ABA signaling-controlled Cd uptake and accumulation in plants.


Subject(s)
Arabidopsis Proteins/metabolism , Arabidopsis/metabolism , Cadmium/pharmacokinetics , Transcription Factors, General/metabolism , Abscisic Acid/metabolism , Arabidopsis/genetics , Arabidopsis Proteins/genetics , Basic Helix-Loop-Helix Transcription Factors/genetics , Basic Helix-Loop-Helix Transcription Factors/metabolism , Basic-Leucine Zipper Transcription Factors/genetics , Basic-Leucine Zipper Transcription Factors/metabolism , Cadmium/metabolism , Feedback, Physiological , Gene Expression Regulation, Plant , Plants, Genetically Modified , Promoter Regions, Genetic , Transcription Factors/genetics , Transcription Factors/metabolism , Transcription Factors, General/genetics
16.
Plant Cell Physiol ; 60(5): 999-1010, 2019 May 01.
Article in English | MEDLINE | ID: mdl-30690513

ABSTRACT

Studies have indicated that the carbon starvation response leads to the reprogramming of the transcriptome and metabolome, and many genes, including several important regulators, such as the group S1 basic leucine zipper transcription factors (TFs) bZIP1, bZIP11 and bZIP53, the SNAC-A TF ATAF1, etc., are involved in these physiological processes. Here, we show that the SNAC-A TF ANAC032 also plays important roles in this process. The overexpression of ANAC032 inhibits photosynthesis and induces reactive oxygen species accumulation in chloroplasts, thereby reducing sugar accumulation and resulting in carbon starvation. ANAC032 reprograms carbon and nitrogen metabolism by increasing sugar and amino acid catabolism in plants. The ChIP-qPCR and transient dual-luciferase reporter assays indicated that ANAC032 regulates trehalose metabolism via the direct regulation of TRE1 expression. Taken together, these results show that ANAC032 is an important regulator of the carbon/energy status that represses photosynthesis to induce carbon starvation.


Subject(s)
Arabidopsis Proteins/metabolism , Arabidopsis/metabolism , Plants, Genetically Modified/metabolism , Transcription Factors/metabolism , Amino Acids/metabolism , Arabidopsis/genetics , Gene Expression Regulation, Plant/genetics , Gene Expression Regulation, Plant/physiology , Plants, Genetically Modified/genetics , Reactive Oxygen Species/metabolism , Signal Transduction/genetics , Signal Transduction/physiology , Trehalose/metabolism
17.
Nat Metab ; 1(5): 570-583, 2019 05.
Article in English | MEDLINE | ID: mdl-32694855

ABSTRACT

Metabolism in mammals is regulated by complex interplay among different organs. Fatty acid synthesis is increased in white adipose tissue (WAT) when it is inhibited in the liver. Here we identify glycoprotein non-metastatic melanoma protein B (Gpnmb) as one liver-WAT cross-talk factor involved in lipogenesis. Inhibition of the hepatic sterol regulatory element-binding protein pathway leads to increased transcription of Gpnmb and promotes processing of the membrane protein to a secreted form. Gpnmb stimulates lipogenesis in WAT and exacerbates diet-induced obesity and insulin resistance. In humans, Gpnmb is tightly associated with body mass index and is a strong risk factor for obesity. Gpnmb inhibition by a neutralizing antibody or liver-specific knockdown improves metabolic parameters, including weight gain reduction and increased insulin sensitivity, probably by promoting the beiging of WAT. These results suggest that Gpnmb is a liver-secreted factor regulating lipogenesis in WAT, and that Gpnmb inhibition may provide a therapeutic strategy in obesity and diabetes.


Subject(s)
Adipose Tissue, White/metabolism , Eye Proteins/metabolism , Insulin Resistance , Liver/metabolism , Membrane Glycoproteins/metabolism , Obesity/metabolism , Animals , Eye Proteins/genetics , Eye Proteins/physiology , Homeostasis , Intracellular Signaling Peptides and Proteins/genetics , Intracellular Signaling Peptides and Proteins/metabolism , Lipid Metabolism , Lipogenesis/genetics , Lipogenesis/physiology , Membrane Glycoproteins/genetics , Membrane Glycoproteins/physiology , Membrane Proteins/genetics , Membrane Proteins/metabolism , Mice , Mice, Knockout , Receptors, Autocrine Motility Factor/genetics , Receptors, Autocrine Motility Factor/metabolism , Up-Regulation
18.
BMC Plant Biol ; 18(1): 362, 2018 Dec 18.
Article in English | MEDLINE | ID: mdl-30563469

ABSTRACT

BACKGROUND: Melatonin and serotonin are well-known signaling molecules that mediate multiple physiological activities in plants, including stress defense, growth, development, and morphogenesis, but their underlying mechanisms have not yet been thoroughly elucidated. In this study, we investigated the roles of melatonin and serotonin in modulating plant growth and defense by integrating physiological and transcriptome analyses in Arabidopsis. RESULTS: Moderate concentrations of melatonin and serotonin did not affect primary root (PR) growth but markedly induced lateral root (LR) formation. Both melatonin and serotonin locally induced the expression of the cell-wall-remodeling-related genes LBD16 and XTR6, thereby inducing LR development. Our data support the idea that melatonin and serotonin lack any auxin-like activity. Treatment with 50 µM serotonin significantly improved PSII activity, and the transcriptome data supported this result. Melatonin and serotonin slightly affected glycolysis and the TCA cycle; however, they markedly regulated the catabolism of several key amino acids, thereby affecting carbon metabolism and energy metabolism. Melatonin and serotonin improved iron (Fe) deficiency tolerance by inducing Fe-responsive gene expression. CONCLUSIONS: Overall, our results from the physiological and transcriptome analyses reveal the roles of melatonin and serotonin in modulating plant growth and stress responses and provide insight into novel crop production strategies using these two phytoneurotransmitters.


Subject(s)
Arabidopsis/growth & development , Arabidopsis/metabolism , Melatonin/metabolism , Serotonin/metabolism , Arabidopsis/drug effects , Arabidopsis/genetics , Carbon/metabolism , Disease Resistance/drug effects , Disease Resistance/physiology , Gene Expression Profiling , Gene Expression Regulation, Plant/drug effects , Iron/metabolism , Melatonin/pharmacology , Nitrogen/metabolism , Photosynthesis/drug effects , Plant Leaves/drug effects , Plant Leaves/physiology , Plant Roots/drug effects , Plant Roots/physiology , Plants, Genetically Modified , Seedlings/drug effects , Seedlings/genetics , Serotonin/pharmacology
19.
Cell Rep ; 19(13): 2823-2835, 2017 06 27.
Article in English | MEDLINE | ID: mdl-28658628

ABSTRACT

Proper intracellular cholesterol trafficking is critical for cellular function. Two lysosome-resident proteins, NPC1 and NPC2, mediate the egress of low-density lipoprotein-derived cholesterol from lysosomes. However, other proteins involved in this process remain largely unknown. Through amphotericin B-based selection, we isolated two cholesterol transport-defective cell lines. Subsequent whole-transcriptome-sequencing analysis revealed two cell lines bearing the same mutation in the vacuolar protein sorting 53 (Vps53) gene. Depletion of VPS53 or other subunits of the Golgi-associated retrograde protein (GARP) complex impaired NPC2 sorting to lysosomes and caused cholesterol accumulation. GARP deficiency blocked the retrieval of the cation-independent mannose 6-phosphate receptor (CI-MPR) to the trans-Golgi network. Further, Vps54 mutant mice displayed reduced cellular NPC2 protein levels and increased cholesterol accumulation, underscoring the physiological role of the GARP complex in cholesterol transport. We conclude that the GARP complex contributes to intracellular cholesterol transport by targeting NPC2 to lysosomes in a CI-MPR-dependent manner.


Subject(s)
Cholesterol/metabolism , Lysosomes/metabolism , Membrane Proteins/genetics , Vesicular Transport Proteins/metabolism , Animals , Biological Transport , Humans , Membrane Proteins/metabolism , Mice
20.
Zhong Yao Cai ; 35(10): 1541-6, 2012 Oct.
Article in Chinese | MEDLINE | ID: mdl-23627115

ABSTRACT

OBJECTIVE: To lay foundation of strains selection through primary selection of 44 strains of Lycium barbarum. METHODS: Used the single plant selection. RESULTS: Screened out 22 strains of Lycium barbarum by preliminary determination of germination rates and seeding rates of hardwood cutting, the growth potential of 2009-26, 2009-21, 2009-17, 2009-29, 2009-2 were better than those of others strains. CONCLUSION: 2009-26 has better growth potential except the length of root, the result provides a basis for further screening can focus on research for 2009-26.


Subject(s)
Agriculture/methods , Germination , Lycium/anatomy & histology , Lycium/growth & development , Biomass , Lycium/physiology , Plant Roots/anatomy & histology , Plant Roots/growth & development , Plant Stems/anatomy & histology , Plant Stems/growth & development , Plants, Medicinal/growth & development , Plants, Medicinal/physiology , Seasons , Seedlings/growth & development , Temperature
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