RESUMEN
BACKGROUND: Neuropathologically, Alzheimer's disease (AD) is characterized by the presence of senile plaques composed of beta-amyloid (Aß) and neurofibrillary tangles made of hyperphosphorylated tau. Aß and p-tau have been shown to impact endoplasmic reticulum homeostasis, DNA damage response and autophagic functions. Intriguingly, alterations in these systems have also been connected to dysfunctions in UFMylation, a ubiquitin-like posttranslational modification. Analogous to ubiquitin, UFM1, is conjugated to substrates via a catalytic cascade involving UFM1-specific set of E1 (UBA5), E2 (UFC1), and a complex that consists of E3 ligase (UFL1), DDRGK1 and CDK5RAP3. UFMylation is reversible, and this is mediated by UFSP2. The UFMylation pathway is essential for brain development as complete loss of function of any of its components result in severe neurodevelopmental disorders. However, alterations in UFMylation and their role in and significance for age-related AD remains unknown. METHOD: We performed Western blot and Meso Scale Discovery based ELISA to measure the protein level of UFM1, UFSP2, tau, p-tau and other UFMylation pathway components in human post-mortem brain. Analyses were performed with RIPA- and 2% SDS-soluble fraction from frontal cortex. To validate our finding in human tissues, we knocked out UFM1 and UFSP2 in ReN cells, a neural progenitor cell model that has already been used to study AD and that can be terminally differentiated in neurons. RESULT: We found a significant reduction of RIPA UFSP2, but an increase of RIPA and SDS UFM1 in AD compared to controls. Strikingly, RIPA UFSP2 had a strong negative correlation with both RIPA and SDS UFM1. Furthermore. UFM1 was significantly increased in UFSP2-KO neurons compared to WT, mirroring the negative correlation between UFM1 and UFSP2 observed in human brain. In addition, RIPA and SDS UFM1 had a strong positive correlation with p-tau, indicating that dysfunctional UFMylation might play an important role for disease pathogenesis. CONCLUSION: Reduction of RIPA soluble UFSP2 in human AD frontal cortex might result in the abnormal accumulation of UFM1 and this might further facilitate the AD pathogenesis. Because of its role for several central AD-relevant pathways, the UFMylation pathway might be a potential therapeutic target for AD.
Asunto(s)
Enfermedad de Alzheimer , Proteínas tau , Humanos , Enfermedad de Alzheimer/patología , Enfermedad de Alzheimer/metabolismo , Proteínas tau/metabolismo , Encéfalo/patología , Encéfalo/metabolismo , Anciano , Anciano de 80 o más Años , Femenino , Masculino , Animales , Enzimas Activadoras de Ubiquitina/metabolismo , Enzimas Activadoras de Ubiquitina/genética , Neuronas/metabolismo , Neuronas/patología , ProteínasRESUMEN
Plant glandular secretory trichomes (GSTs) produce various specialized metabolites. Increasing GST density represents a strategy to enhance the yield of these chemicals; however, the gene regulatory network that controls GST initiation remains unclear. In a previous study of Artemisia annua L., we found that a HD-ZIP IV transcription factor, AaHD1, promotes GST initiation by directly regulating AaGSW2. Here, we identified two AaHD1-interacting transcription factors, namely AaMIXTA-like 2 (AaMYB16) and AaMYB5. Through the generation and characterization of transgenic plants, we found that AaMYB16 is a positive regulator of GST initiation, whereas AaMYB5 has the opposite effect. Notably, neither of them regulates GST formation independently. Rather, they act competitively, by interacting and modulating AaHD1 promoter binding activity. Additionally, the phytohormone jasmonic acid (JA) was shown to be associated with the AaHD1-AaMYB16/AaMYB5 regulatory network through transcriptional regulation via a JASMONATE-ZIM DOMAIN (JAZ) protein repressor. These results bring new insights into the mechanism of GST initiation through regulatory complexes, which appear to have similar functions in a range of vascular plant taxa.
Asunto(s)
Artemisia annua , Artemisia annua/genética , Artemisia annua/metabolismo , Regulación de la Expresión Génica de las Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Tricomas/metabolismoRESUMEN
Glandular secreting trichomes (GSTs) synthesize and secrete large quantities of secondary metabolites, some of which have well-established commercial value. An example is the anti-malarial compound artemisinin, which is synthesized in the GSTs of Artemisia annua. Accordingly, there is considerable interest in understanding the processes that regulate GST density as a strategy to increase artemisinin production. In this study, we identified a GST-specific WRKY transcription factor from A. annua, AaGSW2, which is positively regulated by the direct binding of the homeodomain proteins AaHD1 and AaHD8 to the L1-box of the AaGSW2 promoter. Overexpression of AaGSW2 in A. annua significantly increased GST density, while AaGSW2 knockdown lines showed impaired GST initiation. Ectopic expression of AaGSW2 homologs from two mint cultivars, Mentha spicata and Mentha haplocalyx, in A. annua also induced GST formation. These results reveal a molecular mechanism involving homeodomain and WRKY proteins that controls glandular trichome initiation, at least part of which is shared by A. annua and mint.
Asunto(s)
Artemisia annua , Artemisia annua/genética , Artemisia annua/metabolismo , Regulación de la Expresión Génica de las Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Tricomas/metabolismoRESUMEN
Artemisia annua is well known for biosynthesizing the antimalarial drug artemisinin. Here, a global proteomic profiling of A. annua is conducted with identification of a total of 13 403 proteins based on the genome sequence annotation database. Furthermore, a spectral library is generated to perform quantitative proteomic analysis using data independent acquisition mass spectrometry. Specifically, proteins between two chemotypes that produce high (HAP) and low (LAP) artemisinin content, respectively, are comprehensively quantified and compared. 182 proteins are identified with abundance significantly different between these two chemotypes means after the statistic use the p-value and fold change it is found 182 proteins can reach the demand conditions which represent the expression are significantly different between the high artemisnin content plants (HAPs) and the low artemisnin content plants (LAPs). Data are available via ProteomeXchange with identifier PXD015547. Overall, this current study globally identifies the proteome of A. annua and quantitatively compares the targeted sub-proteomes between the two cultivars of HAP and LAP, providing systematic information on metabolic pathways of A. annua.
Asunto(s)
Artemisia annua/genética , Artemisininas/metabolismo , Proteoma/genética , Proteómica , Artemisia annua/metabolismo , Regulación de la Expresión Génica de las Plantas/genética , Espectrometría de MasasRESUMEN
Genetic mutations in TAR DNA-binding protein 43 (TDP-43) cause amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Importantly, TDP-43 proteinopathy, characterized by aberrant phosphorylation, ubiquitination, cleavage or nuclear depletion of TDP-43 in neurons and glial cells, is a common prominent pathological feature of various major neurodegenerative diseases including ALS, FTD, and Alzheimer's disease (AD). Although the pathomechanisms underlying TDP-43 proteinopathy remain elusive, pathologically relevant TDP-43 has been repeatedly shown to be present in either the inside or outside of mitochondria, and functionally involved in the regulation of mitochondrial morphology, trafficking, and function, suggesting mitochondria as likely targets of TDP-43 proteinopathy. In this review, we first describe the current knowledge of the association of TDP-43 with mitochondria. We then review in detail multiple mitochondrial pathways perturbed by pathological TDP-43, including mitochondrial fission and fusion dynamics, mitochondrial trafficking, bioenergetics, and mitochondrial quality control. Lastly, we briefly discuss how the study of TDP-43 proteinopathy and mitochondrial abnormalities may provide new avenues for neurodegeneration therapeutics.
Asunto(s)
Mitocondrias/metabolismo , Proteinopatías TDP-43/metabolismo , Animales , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Humanos , Mitocondrias/patología , Recambio Mitocondrial , Neuronas/metabolismo , Neuronas/patología , Proteinopatías TDP-43/genética , Proteinopatías TDP-43/patologíaRESUMEN
Artemisinin, the frontline drug against malaria, is a sesquiterpenoid extracted from Artemisia annua. Light has been proposed to play an important role in the activation of artemisinin biosynthesis. Here, we report the basic leucine zipper transcription factor (TF) AaHY5 as a key regulator of light-induced biosynthesis of artemisinin. We show that AaHY5 transcription overlaps with that of artemisinin biosynthesis genes in response to light and in A. annua tissues. Analysis of AaHY5 overexpression and RNAi-suppression lines suggests that AaHY5 is a positive regulator of the expression of artemisinin biosynthesis genes and accumulation of artemisinin. We show that AaHY5 complements the hy5 mutant in Arabidopsis thaliana. Our data further suggest that AaHY5 interacts with AaCOP1, the ubiquitin E3 ligase CONSTITUTIVE PHOTOMORPHOGENIC1 in A. annua. In yeast one-hybrid and transient expression assays, we demonstrate that AaHY5 acts via the TF GLANDULAR TRICHOME-SPECIFIC WRKY 1 (AaGSW1) in artemisinin regulation. In summary, we present a novel regulator of artemisinin gene expression and propose a model in which AaHY5 indirectly controls artemisinin production in response to changing light conditions.
Asunto(s)
Artemisia annua/metabolismo , Artemisininas/metabolismo , Luz , Artemisia annua/efectos de la radiación , Regulación de la Expresión Génica de las Plantas/efectos de la radiación , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Modificadas Genéticamente/metabolismo , Plantas Modificadas Genéticamente/efectos de la radiación , Factores de TranscripciónRESUMEN
Artemisinin is a sesquiterpene lactone produced by the Chinese traditional herb Artemisia annua and is used for the treatment of malaria. It is known that salicylic acid (SA) can enhance artemisinin content but the mechanism by which it does so is not known. In this study, we systematically investigated a basic leucine zipper family transcription factor, AaTGA6, involved in SA signaling to regulate artemisinin biosynthesis. We found specific in vivo and in vitro binding of the AaTGA6 protein to a 'TGACG' element in the AaERF1 promoter. Moreover, we demonstrated that AaNPR1 can interact with AaTGA6 and enhance its DNA-binding activity to its cognate promoter element 'TGACG' in the promoter of AaERF1, thus enhancing artemisinin biosynthesis. The artemisinin contents in AaTGA6-overexpressing and RNAi transgenic plants were increased by 90-120% and decreased by 20-60%, respectively, indicating that AaTGA6 plays a positive role in artemisinin biosynthesis. Importantly, heterodimerization with AaTGA3 significantly inhibits the DNA-binding activity of AaTGA6 and plays a negative role in target gene activation. In conclusion, we demonstrate that binding of AaTGA6 to the promoter of the artemisinin-regulatory gene AaERF1 is enhanced by AaNPR1 and inhibited by AaTGA3. Based on these findings, AaTGA6 has potential value in the genetic engineering of artemisinin production.
Asunto(s)
Artemisia annua/metabolismo , Artemisininas/metabolismo , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Proteínas de Plantas/metabolismo , Ácido Salicílico/metabolismo , Artemisia annua/genética , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/genética , Regulación de la Expresión Génica de las Plantas/genética , Regulación de la Expresión Génica de las Plantas/fisiología , Proteínas de Plantas/genéticaRESUMEN
Glandular trichomes and cuticles are both specialized structures that cover the epidermis of aerial plant organs. The former are commonly regarded as 'biofactories' for producing valuable natural products. The latter are generally considered as natural barriers for defending plants against abiotic and biotic stresses. However, the regulatory network for their formation and relationship remains largely elusive. Here we identify a homeodomain-leucine zipper (HD-ZIP) IV transcription factor, AaHD8, directly promoting the expression of AaHD1 for glandular trichome initiation in Artemisia annua. We found that AaHD8 positively regulated leaf cuticle development in A. annua via controlling the expression of cuticle-related enzyme genes. Furthermore, AaHD8 interacted with a MIXTA-like protein AaMIXTA1, a positive regulator of trichome initiation and cuticle development, forming a regulatory complex and leading to enhanced transcriptional activity in regulating the expression of AaHD1 and cuticle development genes. Our results reveal a molecular mechanism by which a novel HD-ZIP IV/MIXTA complex plays a significant role in regulating epidermal development, including glandular trichome initiation and cuticle formation.
Asunto(s)
Artemisia annua/crecimiento & desarrollo , Complejos Multiproteicos/metabolismo , Epidermis de la Planta/crecimiento & desarrollo , Proteínas de Plantas/metabolismo , Tricomas/crecimiento & desarrollo , Artemisia annua/genética , Artemisia annua/ultraestructura , Secuencia de Bases , Vías Biosintéticas , Regulación de la Expresión Génica de las Plantas , Modelos Biológicos , Epidermis de la Planta/genética , Epidermis de la Planta/ultraestructura , Proteínas de Plantas/genética , Unión Proteica , Transcripción Genética , Tricomas/genética , Tricomas/ultraestructuraRESUMEN
The glandular secretory trichomes (GSTs) on Artemisia annua leaves have the capacity to secrete and store artemisinin, a compound which is the most effective treatment for uncomplicated malaria. An effective strategy to improve artemisinin content is therefore to increase the density of GSTs in A. annua. However, the formation mechanism of GSTs remains poorly understood. To explore the mechanisms of GST initiation in A. annua, we screened myeloblastosis (MYB) transcription factor genes from a GST transcriptome database and identified a MIXTA transcription factor, AaMIXTA1, which is expressed predominantly in the basal cells of GST in A. annua. Overexpression and repression of AaMIXTA1 resulted in an increase and decrease, respectively, in the number of GSTs as well as the artemisinin content in transgenic plants. Transcriptome analysis and cuticular lipid profiling showed that AaMIXTA1 is likely to be responsible for activating cuticle biosynthesis. In addition, dual-luciferase reporter assays further demonstrated that AaMIXTA1 could directly activate the expression of genes related to cuticle biosynthesis. Taken together, AaMIXTA1 regulated cuticle biosynthesis and prompted GST initiation without any abnormal impact on the morphological structure of the GSTs and so provides a new way to improve artemisinin content in this important medicinal plant.
Asunto(s)
Artemisia annua/metabolismo , Artemisininas/metabolismo , Factores de Transcripción/metabolismo , Tricomas/metabolismo , Secuencia de Aminoácidos , Artemisia annua/genética , Artemisia annua/ultraestructura , Regulación de la Expresión Génica de las Plantas , Especificidad de Órganos , Filogenia , Epidermis de la Planta/genética , Epidermis de la Planta/metabolismo , Epidermis de la Planta/ultraestructura , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Modificadas Genéticamente , Alineación de Secuencia , Factores de Transcripción/genética , Tricomas/genética , Tricomas/ultraestructuraRESUMEN
Glandular trichomes are generally considered biofactories that produce valuable chemicals. Increasing glandular trichome density is a very suitable way to improve the productivity of these valuable metabolites, but little is known about the regulation of glandular trichome formation. Phytohormone jasmonate (JA) promotes glandular trichome initiation in various plants, but its mechanism is also unknown. By searching transcription factors regulated by JA in Artemisia annua, we identified a novel homeodomain-leucine zipper transcription factor, HOMEODOMAIN PROTEIN 1 (AaHD1), which positively controls both glandular and nonglandular trichome initiations. Overexpression of AaHD1 in A. annua significantly increased glandular trichome density without harming plant growth. Consequently, the artemisinin content was improved. AaHD1 interacts with A. annua jasmonate ZIM-domain 8 (AaJAZ8), which is a repressor of JA, thereby resulting in decreased transcriptional activity. AaHD1 knockdown lines show decreased sensitivity to JA on glandular trichome initiation, which indicates that AaHD1 plays an important role in JA-mediated glandular trichome initiation. We identified a new transcription factor that promotes A. annua glandular trichome initiation and revealed a novel molecular mechanism by which a homeodomain protein transduces JA signal to promote glandular trichome initiation. Our results also suggested a connection between glandular and nonglandular trichome formations.
Asunto(s)
Artemisia annua/embriología , Artemisia annua/metabolismo , Ciclopentanos/farmacología , Oxilipinas/farmacología , Proteínas de Plantas/metabolismo , Tricomas/embriología , Tricomas/metabolismo , Artemisia annua/efectos de los fármacos , Técnicas de Silenciamiento del Gen , Modelos Biológicos , Organogénesis/efectos de los fármacos , Filogenia , Hojas de la Planta/ultraestructura , Proteínas de Plantas/química , Plantas Modificadas Genéticamente , Dominios Proteicos , Transcripción Genética/efectos de los fármacos , Tricomas/efectos de los fármacos , Tricomas/ultraestructuraRESUMEN
Artemisinin is a type of sesquiterpene lactone well known as an antimalarial drug, and is specifically produced in glandular trichomes of Artemisia annua. However, the regulatory network for the artemisinin biosynthetic pathway remains poorly understood. Exploration of trichome-specific transcription factors would facilitate the elucidation of regulatory mechanism of artemisinin biosynthesis. The WRKY transcription factor GLANDULAR TRICHOME-SPECIFIC WRKY 1 (AaGSW1) was cloned and analysed in A. annua. AaGSW1 exhibited similar expression patterns to the trichome-specific genes of the artemisinin biosynthetic pathway and AP2/ERF transcription factor AaORA. A ß-glucuronidase (GUS) staining assay further demonstrated that AaGSW1 is a glandular trichome-specific transcription factor. AaGSW1 positively regulates CYP71AV1 and AaORA expression by directly binding to the W-box motifs in their promoters. Overexpression of AaGSW1 in A. annua significantly improves artemisinin and dihydroartemisinic acid contents; moreover, AaGSW1 can be directly regulated by AaMYC2 and AabZIP1, which are positive regulators of jasmonate (JA)- and abscisic acid (ABA)-mediated artemisinin biosynthetic pathways, respectively. These results demonstrate that AaGSW1 is a glandular trichome-specific WRKY transcription factor and a positive regulator in the artemisinin biosynthetic pathway. Moreover, we propose that two trifurcate feed-forward pathways involving AaGSW1, CYP71AV1 and AaMYC2/AabZIP1 function in the JA/ABA response in A. annua.
Asunto(s)
Artemisia annua/metabolismo , Artemisininas/metabolismo , Vías Biosintéticas , Proteínas de Plantas/metabolismo , Ácido Abscísico/metabolismo , Artemisia annua/genética , Vías Biosintéticas/genética , Ciclopentanos/metabolismo , Regulación de la Expresión Génica de las Plantas , Genes de Plantas , Glucuronidasa/metabolismo , Modelos Biológicos , Especificidad de Órganos , Oxilipinas/metabolismo , Filogenia , Proteínas de Plantas/genética , Plantas Modificadas Genéticamente , Regiones Promotoras Genéticas , Unión Proteica/genética , Factores de Transcripción/metabolismo , Transcripción Genética , Tricomas/metabolismoRESUMEN
There are many biosynthetic pathways competing for the metabolic flux with the artemisinin biosynthetic pathway in Artemisia annua L. To study the relationship between genes encoding enzymes at branching points and the artemisinin biosynthetic pathway, ß-caryophyllene, ß-farnesene and squalene were sprayed on young seedlings of A. annua. Transient expression assays indicated that the transcription levels of ß-caryophyllene synthase (CPS), ß-farnesene synthase (BFS) and squalene synthase (SQS) were inhibited by ß-caryophyllene, ß-farnesene and squalene, respectively, while expression of some artemisinin biosynthetic pathway genes increased. Thus, inhibition of these genes encoding enzymes at branching points may be helpful to improve the artemisinin content. For further study, the expression levels of four branch pathway genes CPS, BFS, germacrene A synthase (GAS) and SQS were down-regulated by the antisense method in A. annua. In anti-CPS transgenic plants, mRNA levels of BFS and ADS were increased, and the contents of ß-farnesene, artemisinin and dihydroartemisinic acid (DHAA) were increased by 212, 77 and 132%, respectively. The expression levels of CPS, SQS, GAS, amorpha-4,11-diene synthase (ADS), amorphadiene 12-hydroxylase (CYP71AV1) and aldehyde dehydrogenase 1 (ALDH1) were increased in anti-BFS transgenic plants and, at the same time, the contents of artemisinin and DHAA were increased by 77% and 54%, respectively, and the content of squalene was increased by 235%. In anti-GAS transgenic plants, mRNA levels of CPS, BFS, ADS and ALDH1 were increased. The contents of artemisinin and DHAA were enhanced by 103% and 130%, respectively. In anti-SQS transgenic plants, the transcription levels of BFS, GAS, CPS, ADS, CYP71AV1 and ALDH1 were all increased. Contents of artemisinin and DHAA were enhanced by 71% and 223%, respectively, while ß-farnesene was raised to 123%. The mRNA level of artemisinic aldehyde Δ11(13) reductase (DBR2) had changed little in almost all transgenic plants.
Asunto(s)
Artemisia annua/metabolismo , Artemisininas/metabolismo , Vías Biosintéticas , Lactonas/metabolismo , Artemisia annua/efectos de los fármacos , Artemisia annua/enzimología , Artemisia annua/genética , Artemisininas/química , Vías Biosintéticas/efectos de los fármacos , Vías Biosintéticas/genética , Farnesil Difosfato Farnesil Transferasa/antagonistas & inhibidores , Farnesil Difosfato Farnesil Transferasa/metabolismo , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Genes de Plantas , Lactonas/química , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Modificadas Genéticamente , Sesquiterpenos Policíclicos , Pirofosfatasas/antagonistas & inhibidores , Pirofosfatasas/metabolismo , Sesquiterpenos/farmacología , Escualeno/farmacología , Terpenos/farmacologíaRESUMEN
The plant Artemisia annua is well known due to the production of artemisinin, a sesquiterpene lactone that is widely used in malaria treatment. Phytohormones play important roles in plant secondary metabolism, such as jasmonic acid (JA), which can induce artemisinin biosynthesis in A. annua. Nevertheless, the JA-inducing mechanism remains poorly understood. The expression of gene AaMYC2 was rapidly induced by JA and AaMYC2 binds the G-box-like motifs within the promoters of gene CYP71AV1 and DBR2, which are key structural genes in the artemisinin biosynthetic pathway. Overexpression of AaMYC2 in A. annua significantly activated the transcript levels of CYP71AV1 and DBR2, which resulted in an increased artemisinin content. By contrast, artemisinin content was reduced in the RNAi transgenic A. annua plants in which the expression of AaMYC2 was suppressed. Meanwhile, the RNAi transgenic A. annua plants showed lower sensitivity to methyl jasmonate treatment than the wild-type plants. These results demonstrate that AaMYC2 is a positive regulator of artemisinin biosynthesis and is of great value in genetic engineering of A. annua for increased artemisinin production.
Asunto(s)
Artemisia annua/genética , Artemisininas/metabolismo , Reguladores del Crecimiento de las Plantas/farmacología , Factores de Transcripción/metabolismo , Acetatos/farmacología , Artemisia annua/metabolismo , Vías Biosintéticas , Ciclopentanos/farmacología , Expresión Génica , Oxilipinas/farmacología , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Modificadas Genéticamente , Regiones Promotoras Genéticas/genética , Interferencia de ARN , Factores de Transcripción/genéticaRESUMEN
Artemisinin, a sesquiterpene lactone isolated from Artemisia annua L. (sweet wormwood), is extensively used in the treatment of malaria. In order to better understand the metabolism of terpenes in A. annua and the influence of terpene synthases on artemisinin yield, the expression pattern of a monoterpene alcohol dehydrogenase (ADH2) has been studied using transgenic plants expressing promoter-ß-glucuronidase (GUS) fusion. ADH2 played a major role in monoterpenoid biosynthesis including carveol, borneol, and artemisia ketone through in vitro biochemical analysis. In this study, the ADH2 promoter was cloned by the genome walking method. A number of putative cis-acting elements were predicted in promoter region, suggesting that the ADH2 is driven by a complex regulation mechanism. ADH2 gene was highly expressed in old leaves, whereas the artemisinin biosynthetic genes were mainly expressed in bud and young leaves. The expression of ADH2 gene increased quickly during leaf development, revealed by qRT-PCR. GUS expression analysis in different tissues of transgenic A. annua demonstrates that ADH2 expression is exclusively located to T-shaped trichome, not glandular secretory trichome.
Asunto(s)
Transferasas Alquil y Aril/genética , Artemisia annua/genética , Regulación de la Expresión Génica de las Plantas , Glucuronidasa/genética , Regiones Promotoras Genéticas/genética , Proteínas Recombinantes de Fusión/genética , Tricomas/genética , Artemisia annua/citología , Secuencia de Bases , Clonación Molecular , Genómica , Especificidad de Órganos , Hojas de la Planta/genética , Plantas Modificadas GenéticamenteRESUMEN
Artemisinin, the endoperoxide sesquiterpene lactone, is an effective antimalarial drug isolated from the Chinese medicinal plant Artemisia annua L. Due to its effectiveness against multi-drug-resistant cerebral malaria, it becomes the essential components of the artemisinin-based combination therapies which are recommended by the World Health Organization as the preferred choice for malaria tropica treatments. To date, plant A. annua is still the main commercial source of artemisinin. Although semi-synthesis of artemisinin via artemisinic acid in yeast is feasible at present, another promising approach to reduce the price of artemisinin is using plant metabolic engineering to obtain a higher content of artemisinin in transgenic plants. In the past years, an Agrobacterium-mediated transformation system of A. annua has been established by which a number of genes related to artemisinin biosynthesis have been successfully transferred into A. annua plants. In this review, the progress on increasing artemisinin content in A. annua by transgenic approach and its future prospect are summarized and discussed.
Asunto(s)
Artemisia annua/genética , Artemisininas/metabolismo , Genómica/métodos , Artemisia annua/enzimología , Vías Biosintéticas/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Modificadas GenéticamenteRESUMEN
Background: Alzheimer's disease (AD) is characterized by the presence of neurofibrillary tangles made of hyperphosphorylated tau and senile plaques composed of beta-amyloid. These pathognomonic deposits have been implicated in the pathogenesis, although the molecular mechanisms and consequences remain undetermined. UFM1 is an important, but understudied ubiquitin-like protein that is covalently attached to substrates. This UFMylation has recently been identified as major modifier of tau aggregation upon seeding in experimental models. However, potential alterations of the UFM1 pathway in human AD brain have not been investigated yet. Methods: Here we used frontal and temporal cortex samples from individuals with or without AD to measure the protein levels of the UFMylation pathway in human brain. We used multivariable regression analyses followed by Bonferroni correction for multiple testing to analyze associations of the UFMylation pathway with neuropathological characteristics, primary biochemical measurements of tau and additional biochemical markers from the same cases. We further studied associations of the UFMylation cascade with cellular stress pathways using Spearman correlations with bulk RNAseq expression data and functionally validated these interactions using gene-edited neurons that were generated by CRISPR-Cas9. Results: Compared to controls, human AD brain had increased protein levels of UFM1. Our data further indicates that this increase mainly reflects conjugated UFM1 indicating hyperUFMylation in AD. UFMylation was strongly correlated with pathological tau in both AD-affected brain regions. In addition, we found that the levels of conjugated UFM1 were negatively correlated with soluble levels of the deUFMylation enzyme UFSP2. Functional analysis of UFM1 and/or UFSP2 knockout neurons revealed that the DNA damage response as well as the unfolded protein response are perturbed by changes in neuronal UFM1 signaling. Conclusions: There are marked changes in the UFMylation pathway in human AD brain. These changes are significantly associated with pathological tau, supporting the idea that the UFMylation cascade might indeed act as a modifier of tau pathology in human brain. Our study further nominates UFSP2 as an attractive target to reduce the hyperUFMylation observed in AD brain but also underscores the critical need to identify risks and benefits of manipulating the UFMylation pathway as potential therapeutic avenue for AD.
RESUMEN
The ubiquitin kinase-ligase pair PINK1-PRKN identifies and selectively marks damaged mitochondria for elimination via the autophagy-lysosome system (mitophagy). While this cytoprotective pathway has been extensively studied in vitro upon acute and complete depolarization of mitochondria, the significance of PINK1-PRKN mitophagy in vivo is less well established. Here we used a novel approach to study PINK1-PRKN signaling in different energetically demanding tissues of mice during normal aging. We demonstrate a generally increased expression of both genes and enhanced enzymatic activity with aging across tissue types. Collectively our data suggest a distinct regulation of PINK1-PRKN signaling under basal conditions with the most pronounced activation and flux of the pathway in mouse heart compared to brain or skeletal muscle. Our biochemical analyses complement existing mitophagy reporter readouts and provide an important baseline assessment in vivo, setting the stage for further investigations of the PINK1-PRKN pathway during stress and in relevant disease conditions.
RESUMEN
The ubiquitin (Ub) kinase-ligase pair PINK1-PRKN mediates the degradation of damaged mitochondria by macroautophagy/autophagy (mitophagy). PINK1 surveils mitochondria and upon stress accumulates on the mitochondrial surface where it phosphorylates serine 65 of Ub to activate PRKN and to drive mitochondrial turnover. While loss of either PINK1 or PRKN is genetically linked to Parkinson disease (PD) and activating the pathway seems to have great therapeutic potential, there is no formal proof that stimulation of mitophagy is always beneficial. Here we used biochemical and cell biological methods to study single nucleotide variants in the activation loop of PINK1 to modulate the enzymatic function of this kinase. Structural modeling and in vitro kinase assays were used to investigate the molecular mechanism of the PINK1 variants. In contrast to the PD-linked PINK1G411S mutation that diminishes Ub kinase activity, we found that the PINK1G411A variant significantly boosted Ub phosphorylation beyond levels of PINK1 wild type. This resulted in augmented PRKN activation, mitophagy rates and increased viability after mitochondrial stress in midbrain-derived, gene-edited neurons. Mechanistically, the G411A variant stabilizes the kinase fold of PINK1 and transforms Ub to adopt the preferred, C-terminally retracted conformation for improved substrate turnover. In summary, we identify a critical role of residue 411 for substrate receptivity that may now be exploited for drug discovery to increase the enzymatic function of PINK1. The genetic substitution of Gly411 to Ala increases mitophagy and may be useful to confirm neuroprotection in vivo and might serve as a critical positive control during therapeutic development.Abbreviations: ATP: adenosine triphosphate; CCCP: carbonyl cyanide m-chlorophenyl hydrazone; Ub-CR: ubiquitin with C-terminally retracted tail; CTD: C-terminal domain (of PINK1); ELISA: enzyme-linked immunosorbent assay; HCI: high-content imaging; IB: immunoblot; IF: immunofluorescence; NPC: neuronal precursor cells; MDS: molecular dynamics simulation; PD: Parkinson disease; p-S65-Ub: ubiquitin phosphorylated at Ser65; RMSF: root mean scare fluctuation; TOMM: translocase of outer mitochondrial membrane; TVLN: ubiquitin with T66V and L67N mutation, mimics Ub-CR; Ub: ubiquitin; WT: wild-type.
Asunto(s)
Enfermedad de Parkinson , Proteínas Quinasas , Humanos , Proteínas Quinasas/genética , Proteínas Quinasas/metabolismo , Enfermedad de Parkinson/genética , Ubiquitina-Proteína Ligasas/genética , Ubiquitina-Proteína Ligasas/metabolismo , Autofagia , Ubiquitina/metabolismoRESUMEN
Alzheimer's disease (AD) is characterized by amyloid plaques and progressive cerebral atrophy. Here, we report FAM222A as a putative brain atrophy susceptibility gene. Our cross-phenotype association analysis of imaging genetics indicates a potential link between FAM222A and AD-related regional brain atrophy. The protein encoded by FAM222A is predominantly expressed in the CNS and is increased in brains of patients with AD and in an AD mouse model. It accumulates within amyloid deposits, physically interacts with amyloid-ß (Aß) via its N-terminal Aß binding domain, and facilitates Aß aggregation. Intracerebroventricular infusion or forced expression of this protein exacerbates neuroinflammation and cognitive dysfunction in an AD mouse model whereas ablation of this protein suppresses the formation of amyloid deposits, neuroinflammation and cognitive deficits in the AD mouse model. Our data support the pathological relevance of protein encoded by FAM222A in AD.
Asunto(s)
Enfermedad de Alzheimer/genética , Péptidos beta-Amiloides/metabolismo , Proteínas Amiloidogénicas/genética , Disfunción Cognitiva/genética , Proteínas del Tejido Nervioso/genética , Placa Amiloide/genética , Agregación Patológica de Proteínas/genética , Anciano , Anciano de 80 o más Años , Enfermedad de Alzheimer/diagnóstico por imagen , Enfermedad de Alzheimer/patología , Proteínas Amiloidogénicas/metabolismo , Animales , Atrofia/diagnóstico por imagen , Atrofia/genética , Atrofia/patología , Encéfalo/diagnóstico por imagen , Encéfalo/patología , Disfunción Cognitiva/patología , Conjuntos de Datos como Asunto , Modelos Animales de Enfermedad , Femenino , Predisposición Genética a la Enfermedad , Estudio de Asociación del Genoma Completo , Humanos , Masculino , Ratones , Ratones Transgénicos , Persona de Mediana Edad , Proteínas del Tejido Nervioso/metabolismo , Placa Amiloide/patología , Polimorfismo de Nucleótido Simple , Agregación Patológica de Proteínas/diagnóstico por imagen , Agregación Patológica de Proteínas/patologíaRESUMEN
Artemisinin is an important drug for malaria treatment, which is exclusively produced in Artemisia annua. It's important to dissect the regulatory mechanism of artemisinin biosynthesis by diverse plant hormones and transcription factors. Our study shows ethylene, a plant hormone which accelerates flower and leaf senescence and fruit ripening, suppressed the expression of genes encoding three key enzymes ADS, DBR2, CYP71AV1, and a positive regulator AaORA involved in artemisinin biosynthesis. Then we isolated the gene encoding ETHYLENE-INSENSITIVE3 (EIN3), a key transcription factor in ethylene signaling pathway, by screening the transcriptome and genome database from Artemisia annua, named AaEIN3. Overexpressing AaEIN3 suppressed artemisinin biosynthesis, while repressing its expression with RNAi enhanced artemisinin biosynthesis in Artemisia annua, indicating AaEIN3 negatively regulates artemisinin biosynthesis. Further study showed the downregulation of artemisinin biosynthesis by ethylene required the mediation of AaEIN3. AaEIN3 could accelerate leaf senescence, and leaf senescence attenuated the expression of ADS, DBR2, CYP71AV1, and AaORA that are involved in artemisinin biosynthesis. Collectively, our study demonstrated a negative correlation between ethylene signaling and artemisinin biosynthesis, which is ascribed to AaEIN3-induced senescence process of leaves. Our work provided novel knowledge on the regulatory network of plant hormones for artemisinin metabolic pathway.