Improvement of plant resistance to geminiviruses via protein de-S-acylation

Geminiviruses are an important group of viruses that infect a variety of plants and result in heavy agricultural losses worldwide. The homologs of C4 (or L4) in monopartite geminiviruses and AC4 (or AL4) in bipartite geminiviruses are critical viral proteins. The C4 proteins from several geminiviruses are the substrates of S-acylation, a dynamic post-translational modification, for the maintenance of their membrane localization and function in virus infection. Here we initiated a screening and identified a plant protein ABAPT3 (Alpha/Beta Hydrolase Domain-containing Protein 17-like Acyl Protein Thioesterase 3) as the de-S-acylation enzyme of C4 encoded by BSCTV (Beet severe curly top virus). Overexpression of ABAPT3 reduced the S-acylation of BSCTV C4, disrupted its plasma membrane localization, inhibited its function in pathogenesis, and suppressed BSCTV infection. Because the S-acylation motifs are conserved among C4 from different geminiviruses, we tested the effect of ABAPT3 on the C4 protein of ToLCGdV (Tomato leaf curl Guangdong virus) from another geminivirus genus. Consistently, ABAPT3 overexpression also disrupted the S-acylation, subcellular localization, and function of ToLCGdV C4, and inhibited ToLCGdV infection. In summary, we provided a new approach to globally improve the resistance to different types of geminiviruses in plants via de-S-acylation of the viral C4 proteins and it can be extendedly used for suppression of geminivirus infection in crops.

Heat-induced SUMOylation differentially affects bacterial effectors in plant cells

Bacterial pathogens deliver effectors into host cells to suppress immunity. How host cells target these effectors is critical in pathogen-host interactions. SUMOylation, an important type of posttranslational modification in eukaryotic cells, plays a critical role in immunity, but its effect on bacterial effectors remains unclear in plant cells. In this study, using bioinformatic and biochemical approaches, we found that at least 16 effectors from the bacterial pathogen Pseudomonas syringae pv. tomato DC3000 are SUMOylated by the enzyme cascade from Arabidopsis thaliana. Mutation of SUMOylation sites on the effector HopB1 enhances its function in the induction of plant cell death via stability attenuation of a plant receptor kinase BRASSINOSTEROID INSENSITIVE 1 (BRI1)-ASSOCIATED RECEPTOR KINASE 1. By contrast, SUMOylation is essential for the function of another effector, HopG1, in the inhibition of mitochondria activity and jasmonic acid signaling. SUMOylation of both HopB1 and HopG1 is increased by heat treatment, and this modification modulates the functions of these 2 effectors in different ways in the regulation of plant survival rates, gene expression, and bacterial infection under high temperatures. Therefore, the current work on the SUMOylation of effectors in plant cells improves our understanding of the function of dynamic protein modifications in plant-pathogen interactions in response to environmental conditions.

S-acylation of a non-secreted peptide controls plant immunity via secreted-peptide signal activation

Small peptides modulate multiple processes in plant cells, but their regulation by post-translational modification remains unclear. ROT4 (ROTUNDIFOLIA4) belongs to a family of Arabidopsis non-secreted small peptides, but knowledge on its molecular function and how it is regulated is limited. Here, we find that ROT4 is S-acylated in plant cells. S-acylation is an important form of protein lipidation, yet so far it has not been reported to regulate small peptides in plants. We show that this modification is essential for the plasma membrane association of ROT4. Overexpression of S-acylated ROT4 results in a dramatic increase in immune gene expression. S-acylation of ROT4 enhances its interaction with BSK5 (BRASSINOSTEROID-SIGNALING KINASE 5) to block the association between BSK5 and PEPR1 (PEP RECEPTOR1), a receptor kinase for secreted plant elicitor peptides (PEPs), thereby activating immune signaling. Phenotype analysis indicates that S-acylation is necessary for ROT4 functions in pathogen resistance, PEP response, and the regulation of development. Collectively, our work reveals an important role for S-acylation in the cross-talk of non-secreted and secreted peptide signaling in plant immunity.

Childhood-Onset Lupus Nephritis in the Childhood Arthritis and Rheumatology Research Alliance Registry: Short-Term Kidney Status and Variation in Care

OBJECTIVE

The goal was to characterize short-term kidney status and describe variation in early care utilization in a multicenter cohort of patients with childhood-onset systemic lupus erythematosus (cSLE) and nephritis.

METHODS

We analyzed previously collected prospective data from North American patients with cSLE with kidney biopsy-proven nephritis enrolled in the Childhood Arthritis and Rheumatology Research Alliance (CARRA) Registry from March 2017 through December 2019. We determined the proportion of patients with abnormal kidney status at the most recent registry visit and applied generalized linear mixed models to identify associated factors. We also calculated frequency of medication use, both during induction and ever recorded.

RESULTS

We identified 222 patients with kidney biopsy-proven nephritis, with 64% class III/IV nephritis on initial biopsy. At the most recent registry visit at median (interquartile range) of 17 (8-29) months from initial kidney biopsy, 58 of 106 patients (55%) with available data had abnormal kidney status. This finding was associated with male sex (odds ratio [OR] 3.88, 95% confidence interval [95% CI] 1.21-12.46) and age at cSLE diagnosis (OR 1.23, 95% CI 1.01-1.49). Patients with class IV nephritis were more likely than class III to receive cyclophosphamide and rituximab during induction. There was substantial variation in mycophenolate, cyclophosphamide, and rituximab ever use patterns across rheumatology centers.

CONCLUSION

In this cohort with predominately class III/IV nephritis, male sex and older age at cSLE diagnosis were associated with abnormal short-term kidney status. We also observed substantial variation in contemporary medication use for pediatric lupus nephritis between pediatric rheumatology centers. Additional studies are needed to better understand the impact of this variation on long-term kidney outcomes.

Salicylic acid attenuates brassinosteroid signaling via protein de-S-acylation

Brassinosteroids (BRs) are important plant hormones involved in many aspects of development. Here, we show that BRASSINOSTEROID SIGNALING KINASEs (BSKs), key components of the BR pathway, are precisely controlled via de-S-acylation mediated by the defense hormone salicylic acid (SA). Most Arabidopsis BSK members are substrates of S-acylation, a reversible protein lipidation that is essential for their membrane localization and physiological function. We establish that SA interferes with the plasma membrane localization and function of BSKs by decreasing their S-acylation levels, identifying ABAPT11 (ALPHA/BETA HYDROLASE DOMAIN-CONTAINING PROTEIN 17-LIKE ACYL PROTEIN THIOESTERASE 11) as an enzyme whose expression is quickly induced by SA. ABAPT11 de-S-acylates most BSK family members, thus integrating BR and SA signaling for the control of plant development. In summary, we show that BSK-mediated BR signaling is regulated by SA-induced protein de-S-acylation, which improves our understanding of the function of protein modifications in plant hormone cross talk.

SUMO E3 ligase AtMMS21-dependent SUMOylation of AUXIN/INDOLE-3-ACETIC ACID 17 regulates auxin signaling

Changes in plant auxin levels can be perceived and converted into cellular responses by auxin signal transduction. AUXIN/INDOLE-3-ACETIC ACID (Aux/IAA) proteins are auxin transcriptional inhibitors that play important roles in regulating auxin signal transduction. The stability of Aux/IAA proteins is important for transcription initiation and downstream auxin-related gene expression. Here, we report that the Aux/IAA protein IAA17 interacts with the small ubiquitin-related modifier (SUMO) E3 ligase METHYL METHANESULFONATE-SENSITIVE 21 (AtMMS21) in Arabidopsis (Arabidopsis thaliana). AtMMS21 regulated the SUMOylation of IAA17 at the K41 site. Notably, root length was suppressed in plants overexpressing IAA17, whereas the roots of K41-mutated IAA17 transgenic plants were not significantly different from wild-type roots. Biochemical data indicated that K41-mutated IAA17 or IAA17 in the AtMMS21 knockout mutant was more likely to be degraded compared with nonmutated IAA17 in wild-type plants. In conclusion, our data revealed a role for SUMOylation in the maintenance of IAA17 protein stability, which contributes to improving our understanding of the mechanisms of auxin signaling.

SUMOylation facilitates the assembly of a Nuclear Factor-Y complex to enhance thermotolerance in Arabidopsis

Heat stress (HS) has serious negative effects on plant development and has become a major threat to agriculture. A rapid transcriptional regulatory cascade has evolved in plants in response to HS. Nuclear Factor-Y (NF-Y) complexes are critical for this mechanism, but how NF-Y complexes are regulated remains unclear. In this study, we identified NF-YC10 (NF-Y subunit C10), a central regulator of the HS response in Arabidopsis thaliana, as a substrate of SUMOylation, an important post-translational modification. Biochemical analysis showed that the SUMO ligase SIZ1 (SAP AND MIZ1 DOMAIN-CONTAINING LIGASE1) interacts with NF-YC10 and enhances its SUMOylation during HS. The SUMOylation of NF-YC10 facilitates its interaction with and the nuclear translocation of NF-YB3, in which the SUMO interaction motif (SIM) is essential for its efficient association with NF-YC10. Further functional analysis indicated that the SUMOylation of NF-YC10 and the SIM of NF-YB3 are critical for HS-responsive gene expression and plant thermotolerance. These findings uncover a role for the SIZ1-mediated SUMOylation of NF-YC10 in NF-Y complex assembly under HS, providing new insights into the role of a post-translational modification in regulating transcription during abiotic stress responses in plants.

The chromosome-scale assembly of the Salvia rosmarinus genome provides insight into carnosic acid biosynthesis

Rosemary (Salvia rosmarinus) is considered a sacred plant because of its special fragrance and is commonly used in cooking and traditional medicine. Here, we report a high-quality chromosome-level assembly of the S. rosmarinus genome of 1.11 Gb in size; the genome has a scaffold N50 value of 95.5 Mb and contains 40 701 protein-coding genes. In contrast to other diploid Labiataceae, an independent whole-genome duplication event occurred in S. rosmarinus at approximately 15 million years ago. Transcriptomic comparison of two S. rosmarinus cultivars with contrasting carnosic acid (CA) content revealed 842 genes significantly positively associated with CA biosynthesis in S. rosmarinus. Many of these genes have been reported to be involved in CA biosynthesis previously, such as genes involved in the mevalonate/methylerythritol phosphate pathways and CYP71-coding genes. Based on the genomes and these genes, we propose a model of CA biosynthesis in S. rosmarinus. Further, comparative genome analysis of the congeneric species revealed the species-specific evolution of CA biosynthesis genes. The genes encoding diterpene synthase and the cytochrome P450 (CYP450) family of CA synthesis-associated genes form a biosynthetic gene cluster (CPSs-KSLs-CYP76AHs) responsible for the synthesis of leaf and root diterpenoids, which are located on S. rosmarinus chromosomes 1 and 2, respectively. Such clustering is also observed in other sage (Salvia) plants, thus suggesting that genes involved in diterpenoid synthesis are conserved in the Labiataceae family. These findings provide new insights into the synthesis of aromatic terpenoids and their regulation.

Intraarticular steroids as DMARD-sparing agents for juvenile idiopathic arthritis flares: Analysis of the Childhood Arthritis and Rheumatology Research Alliance Registry

BACKGROUND

Children with juvenile idiopathic arthritis (JIA) who achieve a drug free remission often experience a flare of their disease requiring either intraarticular steroids (IAS) or systemic treatment with disease modifying anti-rheumatic drugs (DMARDs). IAS offer an opportunity to recapture disease control and avoid exposure to side effects from systemic immunosuppression. We examined a cohort of patients treated with IAS after drug free remission and report the probability of restarting systemic treatment within 12 months.

METHODS

We analyzed a cohort of patients from the Childhood Arthritis and Rheumatology Research Alliance (CARRA) Registry who received IAS for a flare after a period of drug free remission. Historical factors and clinical characteristics and of the patients including data obtained at the time of treatment were analyzed.

RESULTS

We identified 46 patients who met the inclusion criteria. Of those with follow up data available 49% had restarted systemic treatment 6 months after IAS injection and 70% had restarted systemic treatment at 12 months. The proportion of patients with prior use of a biologic DMARD was the only factor that differed between patients who restarted systemic treatment those who did not, both at 6 months (79% vs 35%, p < 0.01) and 12 months (81% vs 33%, p < 0.05).

CONCLUSION

While IAS are an option for all patients who flare after drug free remission, it may not prevent the need to restart systemic treatment. Prior use of a biologic DMARD may predict lack of success for IAS. Those who previously received methotrexate only, on the other hand, are excellent candidates for IAS.

A diRNA-protein scaffold module mediates SMC5/6 recruitment in plant DNA repair

In eukaryotes, the STRUCTURAL MAINTENANCE OF CHROMOSOME 5/6 (SMC5/6) complex is critical to maintaining chromosomal structures around double-strand breaks (DSBs) in DNA damage repair. However, the recruitment mechanism of this conserved complex at DSBs remains unclear. In this study, using Arabidopsis thaliana as a model, we found that SMC5/6 localization at DSBs is dependent on the protein scaffold containing INVOLVED IN DE NOVO 2 (IDN2), CELL DIVISION CYCLE 5 (CDC5), and ALTERATION/DEFICIENCY IN ACTIVATION 2B (ADA2b), whose recruitment is further mediated by DNA-damage-induced RNAs (diRNAs) generated from DNA regions around DSBs. The physical interactions of protein components including SMC5-ADA2b, ADA2b-CDC5, and CDC5-IDN2 result in formation of the protein scaffold. Further analysis indicated that the DSB localization of IDN2 requires its RNA-binding activity and ARGONAUTE 2 (AGO2), indicating a role for the AGO2-diRNA complex in this process. Given that most of the components in the scaffold are conserved, the mechanism presented here, which connects SMC5/6 recruitment and small RNAs, will improve our understanding of DNA repair mechanisms in eukaryotes.

ABA INSENSITIVE 5 confers geminivirus resistance via suppression of the viral promoter activity in plants

Geminiviruses are a large group of plant viruses that have been a serious threat to worldwide agriculture. Transcription of the virus-encoded genes is necessary for geminiviruses to complete their life cycle, but the host proteins which directly target geminivirus promoters for suppression of viral gene transcription remain to be identified. Using Beet severe curly top virus (BSCTV) which causes severe plant symptoms as a system, we performed a yeast one-hybrid screening and identified ABA INSENSITIVE 5 (ABI5), a critical transcription factor in Abscisic acid (ABA) signaling transduction, as an interactor with the viral promoter. Further data showed that an ABA-responsive element in the viral promoter is necessary for its interaction with ABI5 and symptom development. Overexpression of ABI5 suppresses the transcription activity of the viral promoter and BSCTV infection in Nicotiana benthamiana and Arabidopsis; whilst depletion of ABI5 enhances the infection of BSCTV in Arabidopsis. Taken together, our study uncovered the function of ABI5 in the plant-virus interaction and will provide us with a new strategy to protect crops from geminivirus infection.

Importation of chloroplast proteins under heat stress is facilitated by their SUMO conjugations

Chloroplasts are hypersensitive to heat stress (HS). SUMOylation, a critical post-translational modification, is conservatively involved in HS responses. However, the functional connection between SUMOylation and chloroplasts under HS remains to be studied. The bioinformatics, biochemistry, and cell biology analyses were used to detect the SUMOylation statuses of Arabidopsis nuclear-encoded chloroplast proteins and the effect of SUMOylation on subcellular localization of these proteins under HS. PSBR, a subunit of photosystem II, was used as an example for a detailed investigation of functional mechanisms. After a global SUMOylation site prediction of nuclear-encoded chloroplast proteins, biochemical data showed that most of the selected candidates are modified by SUMO3 in the cytoplasm. The chloroplast localization of these SUMOylation targets under long-term HS is partially maintained by the SUMO ligase AtSIZ1. The HS-induced SUMOylation on PSBR contributes to the maintenance of its chloroplast localization, which is dependent on its chloroplast importation efficiency correlated to phosphorylation. The complementation analysis provided evidence that SUMOylation is essential for the physiological function of PSBR under HS. Our study illustrated a general regulatory mechanism of SUMOylation in maintaining the chloroplast protein importation during HS and provided hints for further investigation on protein modifications associated with plant organelles under stress conditions.

Circ_0059354 aggravates the progression of papillary thyroid carcinoma by elevating ARFGEF1 through sponging miR-766-3p

BACKGROUND

Circular RNAs (circRNAs) have been identified as vital players in tumors, including papillary thyroid carcinoma (PTC). The purpose of this study is to explore the functions of circ_0059354 on PTC development.

METHODS

Quantitative real-time polymerase chain reaction (qRT-PCR) was conducted to examine the levels of circ_0059354, microRNA-766-3p (miR-766-3p) and ADP ribosylation factor guanine nucleotide exchange factor 1 (ARFGEF1). Cell Counting Kit-8 (CCK-8) assay and colony formation assay were proceeded for cell proliferation ability. Transwell assay was conducted for cell migration and invasion. Tube formation assay was employed to examine the angiogenesis ability. Flow cytometry analysis was adopted for cell apoptosis. Western blot assay was conducted for protein levels. Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were utilized to verify the relationships among circ_0059354, miR-766-3p and ARFGEF1. The murine xenograft model was constructed to analyze the function of circ_0059354 in vivo.

RESULTS

Circ_0059354 level was abnormally increased in PTC tissues and cells. Functionally, circ_0059354 silencing suppressed cell proliferation, migration, invasion and angiogenesis and facilitated apoptosis in PTC cells. Circ_0059354 was identified to sponge miR-766-3p, which directly targeted ARFGEF1. Moreover, circ_0059354 directly targeted miR-766-3p to positively regulated ARFGEF1 expression. MiR-766-3p inhibition reversed circ_0059354 knockdown-mediated effect of PTC cell malignant behaviors. Overexpression of miR-766-3p restrained the malignant behaviors of PTC cells, whereas ARFGEF1 elevation reversed the effects. Additionally, circ_0059354 deficiency blocked tumor growth in vivo.

CONCLUSION

Circ_0059354 served as an oncogene in PTC progression through regulating miR-766-3p/ARFGEF1 axis.

Social determinants of health influence disease activity and functional disability in Polyarticular Juvenile Idiopathic Arthritis

BACKGROUND

Social determinants of health (SDH) greatly influence outcomes during the first year of treatment in rheumatoid arthritis, a disease similar to polyarticular juvenile idiopathic arthritis (pJIA). We investigated the correlation of community poverty level and other SDH with the persistence of moderate to severe disease activity and functional disability over the first year of treatment in pJIA patients enrolled in the Childhood Arthritis and Rheumatology Research Alliance Registry.

METHODS

In this cohort study, unadjusted and adjusted generalized linear mixed effects models analyzed the effect of community poverty and other SDH on disease activity, using the clinical Juvenile Arthritis Disease Activity Score-10, and disability, using the Child Health Assessment Questionnaire, measured at baseline, 6, and 12 months.

RESULTS

One thousand six hundred eighty-four patients were identified. High community poverty (≥20% living below the federal poverty level) was associated with increased odds of functional disability (OR 1.82, 95% CI 1.28-2.60) but was not statistically significant after adjustment (aOR 1.23, 95% CI 0.81-1.86) and was not associated with increased disease activity. Non-white race/ethnicity was associated with higher disease activity (aOR 2.48, 95% CI: 1.41-4.36). Lower self-reported household income was associated with higher disease activity and persistent functional disability. Public insurance (aOR 1.56, 95% CI 1.06-2.29) and low family education (aOR 1.89, 95% CI 1.14-3.12) was associated with persistent functional disability.

CONCLUSION

High community poverty level was associated with persistent functional disability in unadjusted analysis but not with persistent moderate to high disease activity. Race/ethnicity and other SDH were associated with persistent disease activity and functional disability.

A223 THE CHAIR STAND TEST IS A RELIABLE FRAILTY METRIC FOR PREDICTING WAITLIST MORBIDITY AND MORTALITY IN PATIENTS WITH CIRRHOSIS

Background

Frailty is defined as a clinical state of increased vulnerability to health and age associated stressors. The liver frailty index (LFI), composed of grip strength, chair stand and balance testing, is an accepted predictor of morbidity and mortality in cirrhosis. With the need for COVID-19 related social distancing, many appointments are being carried out virtually. The chair stand subcomponent of the LFI has the potential to be evaluated virtually, with a high reliability as compared to in-person testing noted in other disease populations.

Aims

To determine if the chair stand test is an independent predictor of morbidity and mortality in patients with cirrhosis.

Methods

822 adult patients with cirrhosis were prospectively enrolled from five centers (3 in Canada, 1 in the United States, and 1 in India). Inclusion criteria included adult patients with cirrhosis. 787 of these patients completed a chair stand test at baseline, measured as the time (seconds) a patient takes to rise from sitting with their arms folded across their chest five times (measured in-person). The times were divided into 3 categories: >15 seconds, between 10 and 15 seconds, and <10 seconds. Patients who could not complete 5 chair stands were classified in the >15 seconds category. Primary outcome was all-cause mortality. Secondary outcome was unplanned all-cause hospital admission. Fine-Gray proportional hazard regression models were used to evaluate the association between the chair stand time and the outcomes. We adjusted for baseline age, sex, and MELD score and accounted for liver transplantation as a competing risk. Cumulative incidence functions were used to create a graphical representation of the survival analysis.

Results

Patients were divided into three groups: group 1, <10 seconds (n = 276); group 2, 10–15 seconds (n = 290); and group 3, >15 seconds (n = 221). Mortality was increased in group 3 in comparison to group 1 (HR 3.21, 95% CI: 2.16–4.78, p<0.001). Similarly, the hazard of non-elective hospitalizations was higher in group 3 in comparison to group 1 (HR 2.24, 95% CI: 1.73–2.91, p<0.001). Overall, patients with chair stand times greater than 15 seconds had increased all-cause mortality (HR 2.78, 95% CI 2.01–3.83, p<0.001) and non-elective hospitalizations (HR 1.84, 95% CI 1.48–2.29, p<0.001) when compared to patients with times less than 15 seconds.

Conclusions

A time to complete 5 chair stands of >15 seconds predicts morbidity and mortality in patients with cirrhosis. This test shows promise as a frailty measure that could be evaluated over a virtual platform.

Funding Agencies

None

Functional characterization of three maize SIZ/PIAS-type SUMO E3 ligases

SUMOylation is a critical post-translational modification that regulates the nature and activity of protein substrates. The reaction is usually enhanced by a SIZ/PIAS-type of SUMO E3 ligase, but the functions of its homologs in maize have not yet been reported. In this study, we functionally characterized three members of this family of SUMO ligases, ZmSIZ1a, ZmSIZ1b, and ZmSIZ1c, from Zea mays. These maize SIZ1 homologs harbor conserved domains and structures with AtSIZ1, suggesting that they are potential functional SUMO ligases, which is supported by further biochemical data. The expression of these maize SIZ1 genes was detectable ubiquitously in different maize tissues and was usually induced by abiotic stresses. Expression of ZmSIZ1 members complements the leaf developmental defects of the AtSIZ1 mutant, suggesting their conserved function in development regulation. Interestingly, overexpression of ZmSIZ1c, but not ZmSIZ1a or ZmSIZ1b, in the wild-type Arabidopsis resulted in early flowering, implying that these members differ in terms of flowering control. Besides, overexpression of these ZmSIZ1 genes also improved salt tolerance in Arabidopsis. Collectively, our functional characterization of the ZmSIZ1 members provides hints for further investigation on the functions of SUMOylation in the development and stress responses in maize.

Does geodemographic segmentation explain differences in route of cancer diagnosis above and beyond person-level sociodemographic variables?

BACKGROUND

Emergency diagnosis of cancer is associated with poorer short-term survival and may reflect delayed help-seeking. Optimal targeting of interventions to raise awareness of cancer symptoms is therefore needed.

METHODS

We examined the risk of emergency presentation of lung and colorectal cancer (diagnosed in 2016 in England). By cancer site, we used logistic regression (outcome emergency/non-emergency presentation) adjusting for patient-level variables (age, sex, deprivation and ethnicity) with/without adjustment for geodemographic segmentation (Mosaic) group.

RESULTS

Analysis included 36 194 and 32 984 patients with lung and colorectal cancer. Greater levels of deprivation were strongly associated with greater odds of emergency presentation, even after adjustment for Mosaic group, which nonetheless attenuated associations (odds ratio [OR] most/least deprived group = 1.67 adjusted [model excluding Mosaic], 1.28 adjusted [model including Mosaic], P < 0.001 for both, for colorectal; respective OR values of 1.42 and 1.18 for lung, P < 0.001 for both). Similar findings were observed for increasing age. There was large variation in risk of emergency presentation between Mosaic groups (crude OR for highest/lowest risk group = 2.30, adjusted OR = 1.89, for colorectal; respective values of 1.59 and1.66 for lung).

CONCLUSION

Variation in risk of emergency presentation in cancer patients can be explained by geodemography, additional to deprivation group and age. The findings support proof of concept for public health interventions targeting all the examined attributes, including geodemography.

An ABHD17-like hydrolase screening system to identify de-S-acylation enzymes of protein substrates in plant cells

Protein S-acylation is an important post-translational modification in eukaryotes, regulating the subcellular localization, trafficking, stability, and activity of substrate proteins. The dynamic regulation of this reversible modification is mediated inversely by protein S-acyltransferases and de-S-acylation enzymes, but the de-S-acylation mechanism remains unclear in plant cells. Here, we characterized a group of putative protein de-S-acylation enzymes in Arabidopsis thaliana, including 11 members of Alpha/Beta Hydrolase Domain-containing Protein 17-like acyl protein thioesterases (ABAPTs). A robust system was then established for the screening of de-S-acylation enzymes of protein substrates in plant cells, based on the effects of substrate localization and confirmed via the protein S-acylation levels. Using this system, the ABAPTs, which specifically reduced the S-acylation levels and disrupted the plasma membrane localization of five immunity-related proteins, were identified respectively in Arabidopsis. Further results indicated that the de-S-acylation of RPM1-Interacting Protein 4, which was mediated by ABAPT8, resulted in an increase of cell death in Arabidopsis and Nicotiana benthamiana, supporting the physiological role of the ABAPTs in plants. Collectively, our current work provides a powerful and reliable system to identify the pairs of plant protein substrates and de-S-acylation enzymes for further studies on the dynamic regulation of plant protein S-acylation.

SUMOylation: A critical transcription modulator in plant cells

Gene transcription is critical for various cellular processes and is precisely controlled at multiple levels, and posttranslational modification (PTM) is a fast and powerful way to regulate transcription factors (TFs). SUMOylation, which conjugates small ubiquitin-related modifier (SUMO) molecules to protein substrates, is a crucial PTM that modulates the activity, stability, subcellular localization, and partner interactions of TFs in plant cells. Here, we summarize the mechanisms of SUMOylation in the regulation of transcription in plant development and stress responses. We also discuss the crosstalk between SUMOylation and other PTMs, as well as the potential functions of SUMOylation in the regulation of transcription-associated complexes on plant chromatin. This summary and perspective will improve understanding of the molecular mechanism of PTMs in plant transcription regulation.

A SUMO ligase OsMMS21 regulates rice development and auxin response

SUMOylation, which transfers the Small Ubiquitin-related Modifier (SUMO) polypeptides to target proteins, regulates diverse cellular processes in eukaryotes. The SUMO conjugation reaction is usually promoted by SUMO E3 ligases, but the molecular functions of this type of enzymes remain unclear in cereal crops. Here, OsMMS21, a SUMO E3 ligase, was functionally characterized in rice (Oryza sativa). Bioinformatics analysis showed that OsMMS21 harbors a conserved SP-RING domain that is essential for the activity of SUMO ligases. Biochemical data indicated that this protein is auto-SUMOylated. Besides, overexpression of OsMMS21 rescued the developmental defects of the AtMMS21 mutant, supporting that OsMMS21 is a functional homolog of the Arabidopsis SUMO ligase AtMMS21. The OsMMS21 rice T-DNA mutant displays a short-root and dwarfism phenotype. RNA-seq data revealed that the expression levels of many genes involved in signaling transduction of hormones, including auxin, are altered in the OsMMS21 mutant. Further results under the auxin treatment showed that the OsMMS21 mutant is insensitive to auxin. Collectively, our results demonstrated the molecular features of OsMMS21 and uncovered the roles of this SUMO ligase in development and auxin response, providing hints for further studies on protein SUMOylation in rice.

Selective optogenetic stimulation of glutamatergic, but not GABAergic, vestibular nuclei neurons induces immediate and reversible postural imbalance in mice

Glutamatergic and GABAergic neurons represent the neural components of the medial vestibular nuclei. We assessed the functional role of glutamatergic and GABAergic neuronal pathways arising from the vestibular nuclei (VN) in the maintenance of gait and balance by optogenetically stimulating the VN in VGluT2-cre and GAD2-cre mice. We demonstrate that glutamatergic, but not GABAergic VN neuronal subpopulation is responsible for immediate and strong posturo-locomotor deficits, comparable to unilateral vestibular deafferentation models. During optogenetic stimulation, the support surface dramatically increased in VN^VGluT2+ mice, and rapidly fell back to baseline after stimulation, whilst it remained unchanged during similar stimulation of VN^GAD2+ mice. This effect persisted when vestibular tactilo kinesthesic plantar inputs were removed. Posturo-locomotor alterations evoked in VN^VGluT2+ animals were still present immediately after stimulation, while they disappeared 1 h later. Overall, these results indicate a fundamental role for VN^VGluT2+ neurons in balance and posturo-locomotor functions, but not for VN^GAD2+ neurons, in this specific context. This new optogenetic approach will be useful to characterize the role of the different VN neuronal populations involved in vestibular physiology and pathophysiology.

Protein modification: A critical modulator in the interaction between geminiviruses and host plants

Geminiviruses are a large group of single-stranded DNA viruses that infect plants and cause severe agricultural losses worldwide. Given geminiviruses only have small genomes that encode a few proteins, viral factors have to interact with host components to establish an environment suitable for virus infection, whilst the host immunity system recognizes and targets these viral components during infection. Post-translational protein modifications, such as phosphorylation, lipidation, ubiquitination, SUMOylation, acetylation and methylation, have been reported to be critical during the interplay between host plants and geminiviruses. Here we summarize the research progress, including phosphorylation and lipidation which usually control the activity and localization of viral factors; as well as ubiquitination and histone modification which are predominantly interfered with by viral components. We also discuss the dynamic competition on protein modifications between host defence and geminivirus efficient infection, as well as potential applications of protein modifications in geminivirus resistance. The summary and perspective of this topic will improve our understanding on the mechanism of geminivirus-plant interaction and contribute to further protection of plants from virus infection.

Evaluating OzHarvest's primary-school Food Education and Sustainability Training (FEAST) program in 10-12-year-old children in Australia: protocol for a pragmatic cluster non-randomized controlled trial

Background

The promotion of healthy eating is a public health priority. Poor dietary behaviours, including low fruit and vegetable (F&V) consumption are of particular concern among children. Novel nutrition promotion strategies are needed to improve F&V consumption. Sustainability education could be used to support nutrition education within the school context. The purpose of this paper is to report the protocol for impact and process evaluation of the school-based Food Education and Sustainability Training (FEAST) program, designed to educate children about sustainability, food waste and nutrition, using hands-on cooking activities.

Methods

A pragmatic, parallel, cluster non-randomized controlled trial with pre- and post-measures, will be implemented among 20 primary schools (10 intervention vs 10 wait-list-control) within NSW, Australia, involving children in Grades 5–6. FEAST is a curriculum-aligned program, delivered as a 1.5-h lesson/week, for a 10-week unit of inquiry, incorporating theory and cooking. FEAST was developed using theoretical frameworks which included Social Cognitive Theory and the Precede-Proceed Planning model. Primary outcomes include children’s self-reported F&V intakes (serves/day). Food literacy constructs such as: nutrition knowledge, food preparation and cooking skills, self-efficacy and behaviours, food waste knowledge and behaviours and food production knowledge, will be assessed as secondary outcomes. Process evaluation will assess program reach, adoption, implementation, maintenance, satisfaction and perceived benefits by teachers and students. An online survey (including quantitative and qualitative questions) was developed for administration at baseline (impact evaluation) and immediately post-intervention (impact and process evaluation). Intervention effects on quantitative study outcomes will be estimated with ​generalised linear mixed models, including random effects and will follow the intention-to-treat principles. Open-ended questions embedded within the surveys will be analysed qualitatively using content and thematic analyses.

Discussion

Results from this trial will provide valuable information on the value of adding environmental sustainability strategies to nutrition education in schools. Results will inform the design of future research and programs focused on primary-school children’s nutrition, sustainability-related behaviours and experiential school-based interventions.

Trial registration

Trial registered 14th December 2020 with the Australian and New Zealand Clinical Trials Registry (ACTRN12620001347954).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-10302-0.

Association of prurigo nodularis and infectious disease hospitalizations: a national cross-sectional study

BACKGROUND

Prurigo nodularis (PN) is associated with a variety of systemic comorbidities, including infectious diseases such as HIV and viral hepatitis. There are limited data on other infectious disease comorbidities in patients with PN.

AIM

To characterize infectious disease hospitalizations among patients with PN and the associated cost burden.

METHODS

We searched the 2016-2017 National Inpatient Sample, a cross-sectional sample of 20% of all US hospitalizations, for infectious disease hospitalizations among patients with PN. Associations of PN with infections and related costs were determined using multivariable logistic and linear regression, adjusting for age, race, sex and insurance type.

RESULTS

PN was associated with any infection overall (OR = 2.98, 95% CI 2.49-3.56), and with HIV, cutaneous, hepatobiliary, central nervous system, bacterial, viral and fungal/parasitic infections and for sepsis. Patients with PN had a higher mean cost of care (US$11 667 vs. US$8893, P < 0.001) and length of stay (5.5 vs. 4.2 days, P < 0.001) for any infection overall and for 7 of 13 other infections. Adjusting for age, race, sex and insurance coverage, PN was associated with higher cost (+30%, 95% CI +17 to +44%) and higher length of stay (+30%, 95% CI +18 to +44%) for any infection overall, and for several specific infections. These associations remained with alternate regression models adjusting for severity of illness.

CONCLUSION

There is a high infectious disease burden among patients with PN, corresponding to higher healthcare utilization and spending. Clinicians must be aware of these associations when treating these patients with immunomodulatory drugs.

A223 FRAILTY INCREASES THE RISK OF CIRRHOSIS DISEASE PROGRESSION, DEATH, AND HOSPITALIZATION IN CIRRHOSIS

Background

In cirrhosis, frailty is associated with increased risk of morbidity and mortality, including an increased risk of hospitalization. While frailty is established as a prognostic marker in cirrhosis, its impact on the progression of cirrhosis, especially in earlier stages of disease, remains unclear.

Aims

To determine the relationship between frailty and risk of cirrhosis progression, mortality, and unplanned hospitalizations in patients with cirrhosis across the spectrum of disease.

Methods

Adult patients with cirrhosis from two centers in North America and one in India were included in this retrospective review of prospectively collected data. Frailty was measured at baseline using the Liver Frailty Index (LFI), comprising grip strength, chair stands, and balance testing. Progression of cirrhosis was defined by an increase from one ordinal stage to the next using the D’Amico classification. Factors associated with progression, mortality, and hospitalizations were evaluated using multivariate competing risk regression models, with transplant as a competing risk.

Results

In total, 822 patients with cirrhosis were included. The median MELD score was 15.5 ± 6.0. Of these patients, 201 (24.5%), 488 (59.4%), and 133 (16.2%) were classified as frail, pre-frail, and robust, respectively. Over a median follow up time of 1.2 years, 60 (7.3%) patients developed progression of cirrhosis, 187 (22.7%) died, 233 (28.3%) underwent liver transplantation, and 342 (41.6%) were alive without cirrhosis progression or transplant. Adjusting for age, sex, and MELD at baseline, being frail was associated with an increased risk of progression to the next cirrhosis stage or to death as compared to being robust (HR 2.47, 95% CI 1.63–3.76, p&lt;0.001). As a continuous variable, every increase in the LFI by 0.1 unit increased the risk of decompensation or death by 1.05-fold (95% CI 1.04–1.07, p&lt;0.001). Similarly, patients who were frail were more likely to be hospitalized as compared to patients who were robust (HR 2.88, 95% CI 2.08–3.98, p&lt;0.001).

Conclusions

Frailty was associated with an increased risk of cirrhosis progression or death, and hospitalization, independent of MELD at baseline. Future studies are needed to evaluate the possibility of slowing cirrhosis disease progression by reversing or preventing frailty.

Funding Agencies

None

Association of MICA gene polymorphisms with thionamide-induced agranulocytosis

BACKGROUND

Thionamide-induced agranulocytosis (TIA), namely antithyroid drug (ATD)-induced agranulocytosis, is one of the most feared adverse effect of ATDs. It is defined as a granulocyte count of less than 0.5 × 10⁹/L after ATD administration. Several studies reported that TIA is associated with human leukocyte antigen (HLA) and nearby genes. Our previous study found that the susceptibility genes of TIA are similar in north China and European populations.

METHODS

We evaluated the associations of 23 candidate single nucleotide polymorphisms (SNPs) in 37 patients with TIA and 254 patients with Graves' disease (GD) as controls by iPLEX MassARRAY system.

RESULTS

Five SNPs in the MHC class I polypeptide-related sequence A(MICA) genes [rs4349859 (p = 1.43E-7); rs145575084 (p = 5.79E-6); rs116135464 (p = 3.70E-5); rs148015908 (p = 3.79E-5) and rs189600525 (p = 2.15E-4)] were found to be significantly associated with TIA after Bonferroni correction. After combining with previous data of rs4349859 and HLA-B*27:05, the haplotype analysis showed that patients carrying P-A-C-A-T-T-A haplotype have a higher risk of TIA (p = 9.76E-7; OR = 14.85, 95% CI 3.63-60.77).

CONCLUSION

Our findings suggest that five high linked SNPs of MICA gene are significantly associated with susceptibility to TIA.

Chromatin-associated SUMOylation controls the transcriptional switch between plant development and heat stress responses

The post-translational protein modification known as SUMOylation has conserved roles in the heat stress responses of various species. The functional connection between the global regulation of gene expression and chromatin-associated SUMOylation in plant cells is unknown. Here, we uncovered a genome-wide relationship between chromatin-associated SUMOylation and transcriptional switches in Arabidopsis thaliana grown at room temperature, exposed to heat stress, and exposed to heat stress followed by recovery. The small ubiquitin-like modifier (SUMO)-associated chromatin sites, characterized by whole-genome ChIP-seq, were generally associated with active chromatin markers. In response to heat stress, chromatin-associated SUMO signals increased at promoter-transcriptional start site regions and decreased in gene bodies. RNA-seq analysis supported the role of chromatin-associated SUMOylation in transcriptional activation during rapid responses to high temperature. Changes in SUMO signals on chromatin were associated with the upregulation of heat-responsive genes and the downregulation of growth-related genes. Disruption of the SUMO ligase gene SIZ1 abolished SUMO signals on chromatin and attenuated rapid transcriptional responses to heat stress. The SUMO signal peaks were enriched in DNA elements recognized by distinct groups of transcription factors under different temperature conditions. These observations provide evidence that chromatin-associated SUMOylation regulates the transcriptional switch between development and heat stress response in plant cells.

Antiretroviral Adherence, Drug Resistance, and the Impact of Social Determinants of Health in HIV-1 Patients in the US

Adherence to antiretroviral therapy (ART) is critical to achieving viral suppression. However, social determinants of health (SDoH) can undermine patient adherence to ART, resulting in drug resistance that compromises future treatment options. We assessed ART adherence and HIV-1 drug resistance at the national and state levels in the US and investigated their associations with SDoH and other HIV-related outcomes. Data were obtained from Symphony Health's Integrated Dataverse (IDV), Monogram/LabCorp Database, as well as national and publicly available databases, including Centers for Disease Control and Prevention (CDC), American Community Survey (ACS), and J. Kaiser Family Foundation (KFF). Inferential analyses were performed to investigate associations using patient-level data, and the results were reported by state and overall within the nation. Correlations between continuous variables were estimated by the Spearman's test, and that between continuous variable and categorical variable were estimated using one-way analysis of variance (ANOVA). State-level rates of poor adherence and resistance ranged from 26 to 55% and 20 to 54%, respectively. Female gender, non-white race, low education, poverty, and unemployment were associated with poor adherence; female gender was associated with drug resistance. Both adherence and resistance were correlated to HIV prevalence rates. Our findings suggest that US patients living with HIV face great challenges associated with poor ART adherence and HIV-1 drug resistance.

Functional characterization of a chloroplast-localized Mn2+(Ca2+)/H+ antiporter, ZmmCCHA1 from Zea mays ssp. mexicana L

The annual Zea mays ssp. mexicana L. is a member of the teosinte group and a close wild relative of maize. Thus, Zea mays ssp. mexicana L. can be effectively used in maize breeding. AtCCHA1 is a Mn2+ and/or Ca2+/H+ antiporter localized in chloroplasts in Arabidopsis. In this study, its homolog from Zea mays ssp. mexicana L., ZmmCCHA1, was isolated and characterized. The transcriptional level of ZmmCCHA1 in Zea mays ssp. mexicana L. was repressed in response to excessive Ca2+ or Mn2+. Heterologous functional complementation assays using yeast mutants showed that ZmmCCHA1 mediates Ca2+ and Mn2+ transport. The ZmmCCHA1 protein was localized in the chloroplasts when expressed in tobacco leaves. Furthermore, ectopic overexpression of ZmmCCHA1 in the Arabidopsis ccha1 mutant rescued the mutant defects on growth and the photosynthetic proteins in the thylakoid membranes. Moreover, the photosynthetic phenotypes of Arabidopsis ccha1 mutant at steady-state were greatly but not completely complemented by the overexpression of ZmmCCHA1. In addition, overexpressing the ZmmCCHA1 rescued the sensitives of PSII in the Arabidopsis ccha1 mutant to Mn2+ deficiency or high Ca2+ condition. These results indicate that the isolated ZmmCCHA1 is the homolog of AtCCHA1 and plays a conserved role in maintaining the Mn2+ and/or Ca2+ homeostasis in chloroplasts which is critical for the function of PSII in photosynthesis.

Characteristics and impacts of itch in children with inflammatory skin disorders

BACKGROUND

Itch is a cardinal feature of paediatric disorders and can impair quality of life. However, few studies have addressed symptoms and impacts of itch in paediatric patients.

OBJECTIVES

We focused on understanding the child's experience of itch and the impact of itch specifically on affected children, including comparison with the adult experience.

METHODS

Semistructured interviews (nine parents, 15 children with itch) explored concerns related to paediatric itch experiences and effects. Themes were compared with those of previous adult interviews. Literature was reviewed to identify the need for a more comprehensive measure of paediatric itch.

RESULTS

Itch quality, intensity, duration and environmental triggers (sweating, climate change, stress and certain fabrics) are important aspects of the child's itch experience. Skin disruption, physical function, concentration, emotional reactions, stigma and relationships/social effects are itch impact themes that emerged. No paediatric-specific scale comprehensively captures the paediatric patient itch experience. However, differences between child and adult reports of itch-related pain, functional limitations, fatigue and restlessness, emotional reactions to itch, and treatment effects emphasize the need for a paediatric-specific measurement tool.

CONCLUSIONS

Children and parents endorse the importance of capturing the paediatric-focused characteristics and impacts of itch in measuring disease severity and response to intervention.

Danger peptide signaling enhances internalization of a geminivirus symptom determinant in plant cells during infection

Geminiviruses are DNA viruses that cause severe diseases in diverse species of plants, resulting in considerable agricultural losses worldwide. C4 proteins are a major symptom determinant in several geminiviruses, including Beet severe curly top virus (BSCTV). Here, we uncovered a novel mechanism by which danger peptide signaling enhances the internalization of BSCTV C4 in plant cells. Previous studies showed that this signaling is important for activation of bacterium- and fungus-triggered immune responses, but its function in plant-virus interactions was previously unknown. Pep1 RECEPTOR1 (PEPR1) and PEPR2 are receptor kinases recognized by Peps (plant elicitor peptides) in the danger peptide pathway. We found that BSCTV C4 up-regulated and interacted with PEPR2 but not PEPR1. The Pep1-PEPR2 complex stimulated the internalization of C4 in both Arabidopsis and Nicotiana benthamiana cells. Furthermore, C4 induced callus formation in Arabidopsis, which was suppressed by PEPR2 overexpression but enhanced in the pepr2 mutants. In the presence of Pep1, overexpression of PEPR2 suppressed BSCTV infection in N. benthamiana. Exogenous Pep1 also reduced BSCTV infection in Arabidopsis in a PEPR2-dependent manner. Thus, PEPR2 recognizes the symptom determinant C4 and enhances its internalization mediated by danger peptides, suppressing BSCTV infection.

SUMOylation Stabilizes the Transcription Factor DREB2A to Improve Plant Thermotolerance

Heat stress (HS) has serious effects on plant development, resulting in heavy agricultural losses. A critical transcription factor network is involved in plant adaptation to high temperature. DEHYDRATION RESPONSIVE ELEMENT-BINDING PROTEIN2A (DREB2A) is a key transcription factor that functions in plant thermotolerance. The DREB2A protein is unstable under normal temperature and is degraded by the 26S proteasome; however, the mechanism by which DREB2A protein stability dramatically increases in response to HS remains poorly understood. In this study, we found that the DREB2A protein of Arabidopsis (Arabidopsis thaliana) is stabilized under high temperature by the posttranslational modification SUMOylation. Biochemical data indicated that DREB2A is SUMOylated at K163, a conserved residue adjacent to the negative regulatory domain during HS. SUMOylation of DREB2A suppresses its interaction with BPM2, a ubiquitin ligase component, consequently increasing DREB2A protein stability under high temperature. In addition, analysis of plant heat tolerance and marker gene expression indicated that DREB2A SUMOylation is essential for its function in the HS response. Collectively, our data reveal a role for SUMOylation in the maintenance of DREB2A stability under high temperature, thus improving our understanding of the regulatory mechanisms underlying HS response in plant cells.

Randomized phase III study of docetaxel plus bavituximab in previously treated advanced non-squamous non-small-cell lung cancer

Background

Bavituximab is a monoclonal antibody that targets phosphatidylserine in the presence of β2 glycoprotein 1 (β2GP1) to exert an antitumor immune response. This phase III trial determined the efficacy of bavituximab combined with docetaxel in patients with previously treated advanced non-small-cell lung cancer (NSCLC).

Patients and methods

Key eligibility criteria included advanced non-squamous NSCLC with disease progression after treatment with platinum-based doublet chemotherapy, evidence of disease control after at least two cycles of first-line therapy, presence of measurable disease, ECOG performance status 0 or 1, adequate bone marrow and organ function, and no recent history of clinically significant bleeding. Eligible patients were randomized 1 : 1 to receive up to six 21-day cycles of docetaxel plus either weekly bavituximab 3 mg/kg or placebo until progression or toxicity. The primary end point was overall survival (OS).

Results

A total of 597 patients were enrolled. Median OS was 10.5 months in the docetaxel + bavituximab arm and was 10.9 months in the docetaxel + placebo arm (HR 1.06; 95% CI 0.88-1.29; P = 0.533). There was no difference in progression-free survival (HR 1.00; 95% CI 0.82-1.22; P = 0.990). Toxicities were manageable and similar between arms. In subset analysis, among patients with high baseline serum β2GP1 levels ≥200 µg/ml, a nonsignificant OS trend favored the bavituximab arm (HR 0.82; 95% CI 0.63-1.06; P = 0.134). Among patients who received post-study immune checkpoint inhibitor therapy, OS favored the bavituximab arm (HR 0.46; 95% CI 0.26-0.81; P = 0.006).

Conclusions

The combination of bavituximab plus docetaxel is not superior to docetaxel in patients with previously treated advanced NSCLC. The addition of bavituximab to docetaxel does not meaningfully increase toxicity. The potential benefit of bavituximab observed in patients with high β2GP1 levels and in patients subsequently treated with immune checkpoint inhibitors requires further investigation.

Clinical trial number

NCT01999673.

Chinese version of the Rotator Cuff Quality of Life questionnaire: Cross-cultural adaptation and validation in rotator cuff-impaired patients in Hong Kong

Purpose:

To adapt the Rotator Cuff Quality of Life (RC-QOL) questionnaire into traditional Chinese (Chi-RC-QOL) and to evaluate the validity and reliability in patients suffering from rotator cuff pathologies in Hong Kong.

Methods:

The Chi-RC-QOL will be constructed using the forward-translation followed by the backward-translation method. Thirty consecutive patients with clinically and radiologically confirmed rotator cuff pathology were recruited. Descriptive statistics will be followed by validity assessment using comparison with the Constant Shoulder (CS) score, University of California Los Angeles (UCLA) Shoulder Rating Scale, and Western Ontario Rotator Cuff (WORC) score. Parametric data will be tested using Pearson’s correlation coefficient for the total scores. Reliability was assessed using a test–retest interval of 30 min. The Cronbach’s α and intraclass correlation coefficient were calculated.

Results:

Cronbach’s α and internal consistency scores were high for all parts of the Chi-RC-QOL, with Cronbach’s α ranging between 0.89 and 0.98. Internal consistency scores range from 0.82 to 0.92, which can be regarded as an excellent correlation. Test–retest reliability was excellent for all parts of the Chi-RC-QOL with good absolute reliability. Chi-RC-QOL correlates well with the CS score, UCLA Shoulder Rating Scale, and the WORC score, with all being statistically significant.

Conclusions:

The current study adapted the RC-QOL to traditional Chinese version. The analysis confirmed the validity and reliability of the Chi-RC-QOL questionnaire.

Level of Evidence:

III.

C-07 Global Precedence: Examining Contributing Effects of Age and Cognitive Functioning

Objective

Global precedence (GP) is an individual’s ability to readily identify global (gestalt) features when both global and local (internal) details are presented. Prior research shows that both age and neurodegenerative diseases, such as Alzheimer’s, affect GP. The goal of the current study is to examine differences in GP between individuals with early-onset Alzheimer’s disease (EOAD; before age 65) and healthy controls (HC).

Method

Fourteen EOAD patients and 6 HC’s recruited from Behavioral Neurology at an academic medical center were included in the current analysis. EOAD participants were diagnosed by clinical history, routine labs, neuroimaging, and neurological examination. Exclusion criteria included unstable medical conditions and history of severe head injury, psychotic disorder, or psychoactive substance use. All participants completed a Mini Mental Status Examination (MMSE) to assess overall cognitive functioning and a 4-item Navon's paradigm task (consisting of a larger letter whose shape is composed of smaller repeats of a different letter) to assess for GP.

Results

Linear regression analysis was performed, with the total score on Navon task as the dependent variable and age, MMSE score, and study group as predictor variables. Analysis yielded significant findings, suggesting a difference in GP performance between the two groups. However, coefficients suggested that while age did not contribute to the between-group difference, MMSE scores significantly accounted for our findings. In fact, when effects of MMSE scores were controlled, the between-group difference was no longer significant.

Conclusion

Findings suggest that individuals with EOAD perform worse on tasks of GP, which may be secondary to overall cognitive decline.

Functional characterization of DiMMS21, a SUMO ligase from Desmodium intortum

SUMOylation is an important protein modification that regulates the properties of substrate proteins in a variety of cellular processes. SUMOylation is catalyzed via a cascade of enzymes and is usually stimulated by SUMO E3 ligases. However, the molecular functions and regulatory mechanisms of SUMOylation in forage crops are unknown. Here, we isolated and functionally characterized DiMMS21, a homolog of the Arabidopsis thaliana SUMO ligase AtMMS21, from the forage legume Desmodium intortum. DiMMS21 is expressed ubiquitously in various D. intortum organs and its encoded protein is found in the cytoplasm and nucleus. Bioinformatics analysis indicated that DiMMS21 contains a conserved SP-RING domain that is required for its activity. Biochemical evidence supports the notion that this protein is a functional SUMO ligase. When expressed in an Arabidopsis mms21 mutant, DiMMS21 completely rescued the defects in root, leaf, and silique development. The results from cotyledon greening and marker gene expression suggested that DiMMS21 can only partially complements the role of AtMMS21 in abscisic acid (ABA) responses. In summary, we characterized the molecular features of DiMMS21 and uncovered potential roles of this SUMO ligase in development and ABA responses, increasing our understanding on the function of SUMOylation in forage crops.

A SUMO ligase AtMMS21 regulates activity of the 26S proteasome in root development

The 26S proteasome is a multi-subunit protease controlling most of the cytosolic and nuclear protein turnover, regulating many cellular events in eukaryotes. However, functional modification on this complex remains unclear. Here, we showed a novel mechanism that a SUMO ligase AtMMS21 regulates activity of the 26S proteasome in root development of Arabidopsis. Our in vitro and in vivo data supported that AtMMS21 interacts with RPT2a, a subunit of the 26S proteasome. The mutants of AtMMS21 and RPT2a display similar developmental defect of roots, suggesting their association in this process. In addition, RPT2a is modified by SUMO3, potentially related to AtMMS21. During development, the activity of the 26S proteasome is lower in both mutants of AtMMS21 and RPT2a, compared with that of wild type. Furthermore, the protein level but not the RNA level of RPT2a is decreased in the absence of AtMMS21, implying stability regulation of the proteasome complex through the AtMMS21-RPT2a interaction. Taken together, the current study would improve our understanding on the regulatory mechanism of the 26S proteasome via protein modification in root development.

Abstract P6-14-07: Not presented

This abstract was not presented at the conference.

Citation Format: Lai J, Antill Y, Richardson G, Vereker M, David S. Not presented [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-14-07.