bims-supasi 2024-12-01 papers

bims-supasi

Biomed News

on Sulfation pathways and signalling

Issue of 2024–12–01
twelve papers selected by
Jonathan Wolf Mueller, University of Birmingham

The diagnostic utility of glycosaminoglycans (GAGs) in the early detection of cancer: a systematic review.
The enhancement mechanisms of chondroitin sulfate on α-amylase activity: Exploring the interaction using in vitro and in silico studies.
Chondroitin sulfate alleviated lipopolysaccharide-induced arthritis in feline and canine articular chondrocytes through regulation of neurotrophic signaling pathways and apoptosis.
Heparan sulfate in cerebrospinal fluid as a biomarker to assess disease severity and for treatment monitoring in patients with Mucopolysaccharidosis Type II: a position statement.
IDH1 R132H and TP53 R248Q Mutations Modulate Glioma Cell Migration and Adhesion on Different ECM Components.
Exploring the Target Genes of Fucosylated Chondroitin Sulfate in Treating Lung Adenocarcinoma Based on the Integration of Bioinformatics Analysis, Molecular Docking, and Experimental Verification.
Effects of catechins, resveratrol, silymarin components and some of their conjugates on xanthine oxidase-catalyzed xanthine and 6-mercaptopurine oxidation.
The Determination of Endogenous Steroids in Hair and Fur: A Systematic Review of Methodologies.
Sulfated Galactan Derivative from Gracilaria fisheri Improves Histopathology and Alters Wound Healing-Related Proteins in the Skin of Excision Rats.
Incorporation of Silver into Sulfate Groups Enhances Antimicrobial and Antiviral Effects of Fucoidan.
AST-120 Protects Cognitive and Emotional Impairment in Chronic Kidney Disease Induced by 5/6 Nephrectomy.
Analysis of the quadruple lsu mutant reveals molecular determinants of the role of LSU proteins in sulfur assimilation in Arabidopsis.

PeerJ. 2024 ;12 e18486

The diagnostic utility of glycosaminoglycans (GAGs) in the early detection of cancer: a systematic review.

Sarah Douglah, Reem Khalil, Reem Kanaan, Moza Almeqbaali, Nada Abdelmonem, Marc Abdelmessih, Yousr Khairalla, Natheer H Al-Rawi.

   Background: Glycosaminoglycans (GAGs) are a family of polysaccharides found abundantly in the extracellular matrix (ECM) of tissues. Research has indicated that the dysregulation of ECM, including changes and disruptions in GAGs, contributes to various cancer hallmarks such as metabolic reprogramming, persistent growth signals, immunosuppression, angiogenesis, tumor invasion, and metastasis.
Objective: This systematic review aims to evaluate the diagnostic accuracy of GAGs, including heparan sulfate (HS), chondroitin sulfate (CS), and hyaluronic acid (HA), in early detection of cancer.
Method: Four databases (PubMed, Scopus, EBSCO, and Ovid) were searched for studies in English within the last 15 years, involving at least 50 human participants. Using a two-stage process: identification and screening, 11 articles were selected and critically appraised using Critical Appraisal Skills Programme (CASP) checklists and Newcastle-Ottawa Scale (NOS) appropriate for each study design.
Result: Eleven studies met the inclusion criteria, encompassing various cancers like renal cell carcinoma (RCC), upper GI cancer (UGI), ovarian cancer, prostate cancer, breast cancer, lung cancer, colorectal cancer and oral cancer. Methodological quality was assessed using two established tools, with no studies exhibiting a high risk of bias. Heparan sulfate levels showed diagnostic potential in renal cancer with a maximum accuracy of 98.9%, achieving 94.7% specificity and 100% sensitivity. Chondroitin sulfate disaccharides emerged as a promising diagnostic marker in ovarian cancer and showed potential as diagnostic markers in renal cancer. However, there were no statistically significant differences in urinary chondroitin sulfate levels between patients and controls in prostate cancer. In breast cancer, hyaluronic acid showed moderate accuracy (AUC = 0.792) in distinguishing metastatic from non-metastatic disease, and a composite score incorporating multiple markers, including HA, showed even higher accuracy (AUC = 0.901) in detecting metastatic breast cancer. HA demonstrated moderate diagnostic accuracy for UGI cancers. Serum HA levels were significantly elevated in patients with oral cancer and pleural malignant mesothelioma and associated with tumor progression in patients with lung cancer. Elevated low molecular weight form of hyaluronan (~6 k Da HA) levels were found in colorectal cancer tissues.
Conclusion: GAGs hold potential as early cancer detection biomarkers. Further validation with larger, diverse populations is needed to validate their diagnostic accuracy and clinical utility.

Keywords:  Cancer; Chondroitin sulfate; Gycosaminoglycans; Heparan sulfate; Hyaluronic acid

DOI:  https://doi.org/10.7717/peerj.18486
Food Chem. 2024 Nov 26. pii: S0308-8146(24)03880-9. [Epub ahead of print]466 142230

The enhancement mechanisms of chondroitin sulfate on α-amylase activity: Exploring the interaction using in vitro and in silico studies.

Yuhang Liu, Shuangyan Zhou, Zhe Qiang, Shuyi Wu, Chunyan Zhang, Quan Sun, Xiaohong He, Pingan Chang, Huimin Pang.

  Glycosaminoglycans (GAG) are bioactive polysaccharide rich in -SO3- and -COO- groups, also known as acidic mucopolysaccharides. In this study, the feasibility of three structurally distinct forms of chondroitin sulfate (CS-A, CS-C, and CS-D) from the GAG family was explored as a potential strategy to enhance industrial α-amylase activity. All three CSs were found to increase α-amylase activity to varying degrees, with CS-D showing the most significant increase, exceeding 78 %. Furthermore, fluorescence quenching experiments indicated that the interaction between CS and α-amylase is primarily driven by hydrophobic interactions. In silico, molecular docking revealed that the sulfate groups of all three CSs form hydrogen bonds with α-amylase, with CS-D exhibiting the lowest binding energy due to its two sulfate groups. Kinetic simulations further suggested that binding to CS increases the flexibility of key active site residues (Asp197, Glu233, and Asp300), modifies the secondary structure, and enlarges the substrate-binding pocket, thereby promoting α-amylase's hydrolytic activity. Thus, this work revealed CS as an α-amylase activator and further elucidated its interaction mechanism using in vitro and in silico studies, which may be beneficial to apply CS in pharmaceutical or food industry.

Keywords:  Activation mechanism; Chondroitin sulfate; Dynamics simulation; Molecular docking; α-Amylase

DOI:  https://doi.org/10.1016/j.foodchem.2024.142230
Tissue Cell. 2024 Nov 26. pii: S0040-8166(24)00343-4. [Epub ahead of print]91 102642

Chondroitin sulfate alleviated lipopolysaccharide-induced arthritis in feline and canine articular chondrocytes through regulation of neurotrophic signaling pathways and apoptosis.

Huasong Bai, Tong Liu, Hengyan Wang, Yunliang Li, Zhanzhong Wang.

  Osteoarthritis (OA) is a pervasive degenerative joint disease affecting companion animals, characterized by chronic inflammation and cartilage degradation. However, the effectiveness of chondroitin sulfate (CS) in treating OA in dogs and cats remains controversial. This study aimed to determine the therapeutic effects and molecular mechanisms of CS on lipopolysaccharide (LPS)-induced inflammation in feline and canine articular chondrocytes (FAC and CAC) at the cellular level in vitro. Our findings demonstrated that CS treatment (800 µg/mL) significantly enhanced cell viability and reduced oxidative stress in FAC and CAC, as evidenced by decreased levels of reactive oxygen species and increased activities of antioxidant enzymes. Furthermore, CS treatment effectively suppressed LPS-induced secretion of pro-inflammatory cytokines, including interleukin-1, tumor necrosis factor-α, interleukin-8, interleukin-10, and matrix metalloproteinases-3, and reduced apoptosis, as confirmed by fluorescence staining and flow cytometry. Transcriptomic analysis revealed that CS upregulated neurotrophic signaling pathways, promoting cell survival and proliferation. Metabolomic analysis indicated that CS treatment upregulated metabolites associated with glycerophospholipid and purine metabolism, suggesting enhanced membrane integrity and energy metabolism. Conversely, pathways involved in protein catabolism and arachidonic acid metabolism were downregulated, indicating a reduction in inflammatory mediators. Collectively, these findings elucidate the multifaceted role of CS in modulating chondrocyte metabolism and inflammatory responses, highlighting its potential to alleviate OA.

Keywords:  Canine chondrocytes; Chondroitin sulfate; Feline chondrocytes; Inflammation; Osteoarthritis; Transcriptomics

DOI:  https://doi.org/10.1016/j.tice.2024.102642
Orphanet J Rare Dis. 2024 Nov 26. 19(1): 436

Heparan sulfate in cerebrospinal fluid as a biomarker to assess disease severity and for treatment monitoring in patients with Mucopolysaccharidosis Type II: a position statement.

Roberto Giugliani, Ana Cecília Menezes de Siqueira, Emerson Santana Santos, Emília Katiane E A Leão, Gerson da Silva Carvalho, Mara Lúcia Schmitz Ferreira Santos, Salmo Raskin, Ana Maria Martins.

  Patients with mucopolysaccharidosis type II (MPS II) can present with a severe neuronopathic phenotype or an attenuated non-neuronopathic phenotype. In the light of the recent development of drugs that cross the blood-brain barrier for treatment of neurologic MPS II symptoms, it is critical to define biomarkers that objectively differentiate phenotypes and monitor therapeutic outcomes of advanced treatments. In December 2023, a panel of Brazilian experts discussed the potential of quantifying heparan sulfate (HS) in the cerebrospinal fluid (CSF) as a biomarker for assessing neurological impairment in patients with MPS II, as well as the potential of the molecule as an objective parameter for therapeutic monitoring. Based on scientific evidence, the experts concluded that HS in CSF is predominantly derived from the brain and reflects neurological impairment in patients with MPS II. CSF HS levels may help differentiate between neuronopathic and non-neuronopathic forms of MPS II, with preliminary observations suggesting a potential threshold around 4,000 ng/mL when HS quantification is performed using the same method described in clinical studies of pabinafusp alfa. According to the authors, monitoring HS levels in CSF can serve as an objective parameter for assessing the effectiveness of treatment with drugs that cross the blood-brain barrier. The recommended timing of HS evaluations in CSF of patients with the severe phenotype is: (i) before treatment; (ii) six months after starting treatment; and (iii) two years after starting treatment. The same monitoring scheme is recommended for patients with the attenuated MPS II phenotype, however, after two years of treatment, the physician may elect to perform regular neurocognitive evaluations instead of measuring HS in CSF. Lastly, the authors reinforced the importance of evaluating adherence to treatment, including interruptions, to provide a more meaningful assessment of the treatment's real-world impact and to determine the ideal timing of CSF collection for therapeutic monitoring.

Keywords:  Biomarkers; Blood-brain barrier; Cerebrospinal fluid; Heparan sulfate; Mucopolysaccharidosis type II

DOI:  https://doi.org/10.1186/s13023-024-03463-9
Int J Mol Sci. 2024 Nov 13. pii: 12178. [Epub ahead of print]25(22):

IDH1 R132H and TP53 R248Q Mutations Modulate Glioma Cell Migration and Adhesion on Different ECM Components.

Mikhail E Shmelev, Andrei A Pilnik, Nikita A Shved, Alina O Penkova, Valeriia S Gulaia, Vadim V Kumeiko.

  Mutations in IDH1 and TP53 have a significant impact on glioma prognosis and progression; however, their roles in tumor cell invasion in terms of interactions with particular components of the extracellular matrix (ECM) are still unclear. Using gene editing protocol based on CRISPR-Cas 9 with cytidine deaminase, we introduced point mutations into U87MG glioblastoma cells to establish modified cell lines with heterozygous IDH1 R132H, homozygous TP53 R248Q and heterozygous IDH1 R132H, homozygous TP53 R248Q genotypes. A comparative study of cell migration on major ECM components was carried out by high-content microscopy. IDH1 R132H mutation introduced to U87MG glioblastoma cells was shown to decrease the migration speed on Matrigel and collagen IV substrates compared to the wild-type. This data were supported by cell adhesion quantification via the lateral shift assay performed by atomic force microscopy (AFM). TP53 R248Q mutation increased cell adhesion to various substrates and significantly promoted cell migration on hyaluronic acid and chondroitin sulfate but did not change the migration rates on laminin and collagens IV and I. A double-mutant genotype produced by consequently introducing IDH1 R132H and TP53 R248Q to parental glioblastoma cells was characterized by the highest migration among all the cell lines, with particularly faster motility on chondroitin sulfate. These findings underscore the complex interactions between glioma cells, with the most important driver mutations and specific ECM components regulating cancer cell migration, offering valuable insights for potential therapeutic targets in glioma treatment.

Keywords:  Matrigel; atomic force microscopy; brain matrix; chondroitin sulfate; collagen I; collagen IV; hyaluronic acid; laminin

DOI:  https://doi.org/10.3390/ijms252212178
ACS Omega. 2024 Nov 19. 9(46): 46312-46322

Exploring the Target Genes of Fucosylated Chondroitin Sulfate in Treating Lung Adenocarcinoma Based on the Integration of Bioinformatics Analysis, Molecular Docking, and Experimental Verification.

Nana Li, Xinhong Zhu, Hua Zhang, Xiaohui Yang, Mingju Shao, Shichao Cui, Cunzhi Lin.

Fucosylated chondroitin sulfate (FCS), extracted from sea cucumbers' body walls, has been found to inhibit the proliferation of lung adenocarcinoma (LUAD) cells. However, there have been few studies of the associated drug targets. This study combined bioinformatics analysis and molecular docking to screen the main targets of FCS intervention in LUAD. Moreover, an experimental validation was performed. First, we downloaded the LUAD gene data set from The Cancer Genome Atlas (TCGA) database and the cisplatin (DDP) resistance gene data set of LUAD A549 cells from the Gene Expression Omnibus (GEO) database. Nine significant genes (PLK1, BUB1, CDK1, CDC20, CCNB1, BUB1B, KIF11, CCNB2, and DLAGP5) were identified by bioinformatics analysis, and these nine genes overlapped in both data sets. Then, molecular docking results showed that FCS had a better affinity with target proteins BUB1 and PLK1. Further experimental verification revealed that FCS inhibited the growth of A549 cells and increased the sensitivity of A549 cells to DDP. Quantitative real-time polymerase chain reaction (qRT-PCR) revealed that A549 cells treated with FCS exhibited down-regulated BUB1 and PLK1 mRNA expression. At the same time, FCS+DDP treatment resulted in a more significant reduction in BUB1 and PLK1 mRNA expression than DDP or FCS treatment alone. These findings reveal potential targets of FCS for LUAD and provide clues for the development of FCS as a potential anticancer agent.

DOI: https://doi.org/10.1021/acsomega.4c07295
J Sci Food Agric. 2024 Nov 28.

Effects of catechins, resveratrol, silymarin components and some of their conjugates on xanthine oxidase-catalyzed xanthine and 6-mercaptopurine oxidation.

Tímea Bencsik, Orsolya Balázs, Róbert G Vida, Balázs Z Zsidó, Csaba Hetényi, Kateřina Valentová, Miklós Poór.

   BACKGROUND: Over the past two decades, the global incidence of gout has markedly increased, affecting people worldwide. Considering the side effects of xanthine oxidase (XO) inhibitor drugs (e.g. allopurinol and febuxostat) used in the treatment of hyperuricemia and gout, the potential application of phytochemicals has been widely studied. In addition, XO also takes part in the elimination of certain drugs, including 6-mercaptopurine. In the current explorative study, we aimed to examine the potential effects of tea catechins, resveratrol, silymarin flavonolignans and some of their conjugated metabolites on XO-catalyzed xanthine and 6-mercaptopurine oxidation, applying in vitro assays and modeling studies.
RESULTS: Catechins, resveratrol and resveratrol conjugates exerted no or only weak inhibitory effects on XO. Silybin A, silybin B and isosilybin A were weak, silychristin was a moderate, while 2,3-dehydrosilychristin was a potent inhibitor of the enzyme. Sulfate metabolites of silybin A, silybin B and isosilybin A were considerably stronger inhibitors compared to the parent flavonolignans, and the sulfation of 2,3-dehydrosilychristin slightly increased its inhibitory potency. Silychristin was the sole flavonolignan tested, where sulfate conjugation decreased its inhibitory effect.
CONCLUSION: 2,3-Dehydrosilychristin seems to be a promising candidate for examining its in vivo antihyperuricemic effects, because both the parent compound and its sulfate conjugate are highly potent inhibitors of XO. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Keywords:  catechins; enzyme inhibition; resveratrol; silymarin; sulfate conjugates; xanthine oxidase

DOI:  https://doi.org/10.1002/jsfa.14045
J Steroid Biochem Mol Biol. 2024 Nov 27. pii: S0960-0760(24)00197-3. [Epub ahead of print] 106649

The Determination of Endogenous Steroids in Hair and Fur: A Systematic Review of Methodologies.

Padraig Maher, Martin Healy, Eamon Laird, Jelena Marunica Karšaj, Wei Gao, Lina Zgaga.

   BACKGROUND: Endogenous steroid hormone assessment is essential for clinical practice. These are typically measured in blood. However, the measurement of these hormones in hair samples is becoming more popular so we have reviewed the methodologies used for this to-date.
METHODS: Ovid Medline, CINAHL, Psychinfo, and EMBASE were searched to identify manuscripts that analysed cortisol, testosterone, androstenedione, 17-hydroxyprogesterone (17OHP), dehydroepiandrosterone sulphate (DHEAS), and/or 25-hydroxyvitamin D (25(OH)D), in hair or fur. Data related to measurement procedures were extracted and analysed.
RESULTS: The systematic review included a total of 180 papers, with 80% published in the past 8 years, 67% in human and 33% animal studies. Cortisol was by far the most common analyte. Incomplete reporting on sample harvest, preparation, and measurement procedures was common. Typically, samples were collected from posterior vertex of humans or back/neck of animals, weighing between 11-50mg (with a range of 1.25-1000mg). Samples were usually stored at room temperature, often using aluminium foil. Isopropanol was the most common cleaning solution. Hair was normally powdered or segmented prior to extraction. Extraction was typically carried out over 18-24hours using methanol. Validation and precision information was provided in 47% of studies.
CONCLUSIONS: This systematic review highlights the lack of standardisation in the analysis of endogenous steroids in hair. Reporting was typically incomplete, and assay validations were partial or absent. Together, these limit the value of these exciting new methods and hold back transition to clinical use.

Keywords:  17-hydroxyprogesterone (17OHP); androstenedione; cortisol; dehydroepiandrosterone sulphate (DHEAS); hair; hair analysis; steroids; testosterone; vitamin D

DOI:  https://doi.org/10.1016/j.jsbmb.2024.106649
Front Biosci (Landmark Ed). 2024 Nov 19. 29(11): 388

Sulfated Galactan Derivative from Gracilaria fisheri Improves Histopathology and Alters Wound Healing-Related Proteins in the Skin of Excision Rats.

Kamonwan Jongsomchai, Arnon Pudgerd, Waraporn Sakaew, Kanokpan Wongprasert, José Kovensky, Tawut Rudtanatip.

   BACKGROUND: The biological activities of sulfated polysaccharides (SP) are well-documented, especially regarding wound healing. Sulfated galactan (SG), a type of SP extracted from the red seaweed Gracilaria fisheri, has been identified as having multiple therapeutic properties related to its wound healing capacity. Recent research indicates that degraded SG (DSG) from G. fisheri, when combined with octanoyl ester (DSGO), can improve wound healing in fibroblasts. However, the effectiveness of natural products in clinical settings often differs from in vitro results. This study aimed to develop and evaluate ointments containing DSG and DSGO for skin repair in an animal model.
METHODS: Twenty-four Wistar rats were divided into four groups: (1) normal control, (2) ointment control, (3) DSG ointment, and (4) DSGO ointment. After inducing full-thickness excision wounds, these ointments were applied to the wounds. Wound contraction rate, histopathology, and protein related wound healing expression were then elucidated.
RESULTS: Our findings showed that both DSG and DSGO ointments significantly enhanced wound closure compared to the control groups. Histopathological and biochemical analyses indicated increased extracellular matrix production and fibroblasts, marked by improved fibroblast activity, neovascularization, and collagen deposition. Furthermore, immunohistochemistry and immunoblot analysis revealed that the ointments altered the expression of Ki67, α-smooth muscle actin (α-SMA), E-cadherin, vimentin, collagen, and components of the Smad signaling pathway, all of which are crucial for wound healing. The results also suggested that the DSGO ointment was marginally more effective in promoting wound healing in this model.
CONCLUSIONS: These results indicate that ointment supplemented with DSG and DSGO have the potential to enhance skin repair by improving histopathology and altering wound healing-related proteins.

Keywords:  developed ointment; excision model; extracellular matrix; sulfated galactan derivative; wound healing

DOI:  https://doi.org/10.31083/j.fbl2911388
Mar Drugs. 2024 Oct 29. pii: 486. [Epub ahead of print]22(11):

Incorporation of Silver into Sulfate Groups Enhances Antimicrobial and Antiviral Effects of Fucoidan.

Akira Iwata, Mayuko Yamamoto-Fujimura, Suzuka Fujiwara, Saya Tajima, Takahide Shigeyama, Moriya Tsukimoto, Tatsuya Ibuki, Akito Kataoka-Kato.

  The COVID-19 pandemic has significantly impacted our daily lives. Routine infection-control measures present an effective preventive strategy for a new infectious disease outbreak. Fucoidan, a fucose-rich sulfated polysaccharide found in brown algae, exhibits antiviral activity. Moreover, fucoidan exerts an antimicrobial effect; however, it requires considerably higher concentrations than those needed for its antiviral effect. In this study, we aimed to enhance the antimicrobial activity of fucoidan and prepared a fucoidan silver salt (Ag-Fuc) by incorporating silver ions into the sulfate groups of Yakult Fucoidan derived from Cladosiphon okamuranus Tokida. The fucoidan exhibited a weak inhibitory effect on Escherichia coli growth at significantly higher concentrations, whereas Ag-Fuc inhibited the growth of E. coli and Staphylococcus epidermidis at concentrations comparable to those required for its antiviral effects. Moreover, Ag-Fuc inhibited the growth of Cladosporium cladosporioides. Infections of human cells with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza A virus were more effectively inhibited by lower concentrations of Ag-Fuc compared with fucoidan. Overall, silver ions added to the sulfate groups induced strong antimicrobial activity and enhanced the antiviral effect of fucoidan. We suggest a wide application of Ag-Fuc as a routine preventive material to avoid new infectious disease pandemics.

Keywords:  SARS-CoV-2; antibacterial activity; antifungal activity; antiviral activity; fucoidan; influenza virus; silver

DOI:  https://doi.org/10.3390/md22110486
Brain Sci. 2024 Oct 22. pii: 1043. [Epub ahead of print]14(11):

AST-120 Protects Cognitive and Emotional Impairment in Chronic Kidney Disease Induced by 5/6 Nephrectomy.

Yeon Hee Yu, Hyuna Im, Samel Park, Beomjong Song, Dae-Kyoon Park, Duk-Soo Kim, Hyo-Wook Gil.

   BACKGROUND: Uremic toxins resulting from chronic kidney disease (CKD) can cause cognitive and emotional disorders, as well as cardiovascular diseases. Indoxyl sulfate (IS) and p-cresol are notable uremic toxins found in patients with CKD. However, few studies have investigated whether reducing uremic toxins can alleviate cognitive and emotional disorders associated with CKD.
METHODS: We studied the effects of AST-120, which lowers IS levels, through behavioral tests, local field potentials, field excitatory postsynaptic potentials, and histological experiments in a 5/6 nephrectomy CKD model.
RESULTS: We confirmed AST-120's effectiveness in CKD by measuring serum creatinine, blood urea nitrogen, and IS levels and performing renal tissue staining. Behavioral phenotypes indicated an alleviation of cognitive and anxiety disorders following AST-120 treatment in CKD-induced rats, which was further validated through local field potentials and field excitatory postsynaptic potential recordings. Double immunofluorescence staining for aquaporin-4 and glial fibrillary acidic protein in the hippocampus of CKD rats treated with AST-120 showed reduced coexpression.
CONCLUSIONS: Our findings demonstrate the potential therapeutic effects of AST-120 in lowering IS levels and improving cognitive and emotional impairments associated with CKD.

Keywords:  AST-120; blood–brain barrier; chronic kidney disease; cognitive phenotypes; indoxyl sulfate

DOI:  https://doi.org/10.3390/brainsci14111043
Plant J. 2024 Nov 29.

Analysis of the quadruple lsu mutant reveals molecular determinants of the role of LSU proteins in sulfur assimilation in Arabidopsis.

Justyna Piotrowska, Anna Wawrzyńska, Marcin Olszak, Michal Krzyszton, Anastasia Apodiakou, Saleh Alseekh, José María López Ramos, Rainer Hoefgen, Stanislav Kopriva, Agnieszka Sirko.

  Because plants are immobile, they have developed intricate mechanisms to sense and absorb nutrients, adjusting their growth and development accordingly. Sulfur is an essential macroelement, but our understanding of its metabolism and homeostasis is limited. LSU (RESPONSE TO LOW SULFUR) proteins are plant-specific proteins with unknown molecular functions and were first identified during transcriptomic studies on sulfur deficiency in Arabidopsis. These proteins are crucial hubs that integrate environmental signals and are involved in the response to various stressors. Herein, we report the direct involvement of LSU proteins in primary sulfur metabolism. Our findings revealed that the quadruple lsu mutant, q-lsu-KO, which was grown under nonlimiting sulfate conditions, exhibited a molecular response resembling that of sulfur-deficient wild-type plants. This led us to explore the interactions of LSU proteins with sulfate reduction pathway enzymes. We found that all LSU proteins interact with ATPS1 and ATPS3 isoforms of ATP sulfurylase, all three isoforms of adenosine 5´ phosphosulfate reductase (APR), and sulfite reductase (SiR). Additionally, in vitro assays revealed that LSU1 enhances the enzymatic activity of SiR. These results highlight the supportive role of LSU proteins in the sulfate reduction pathway.

Keywords:  Arabidopsis thaliana; LSU (RESPONSE TO LOW SULFUR); sulfate deficiency; sulfite reductase; sulfur metabolism

DOI:  https://doi.org/10.1111/tpj.17155