ABSTRACT
In plants, vascular stem cells located in the cambium continuously undergo self-renewal and differentiation during secondary growth. Recent advancements in cell sorting techniques have enabled access to the transcriptional regulatory framework of cambial cells. However, mechanisms underlying the robust control of vascular stem cells remain unclear. Here, we identified a new cambium-related regulatory module through co-expression network analysis using multiple transcriptome datasets obtained from an ectopic vascular cell transdifferentiation system using Arabidopsis cotyledons, Vascular cell Induction culture System Using Arabidopsis Leaves (VISUAL). The cambium gene list included a gene encoding the transcription factor BES1/BZR1 Homolog 3 (BEH3), whose homolog BES1 negatively affects vascular stem cell maintenance. Interestingly, null beh3 mutant alleles showed a large variation in their vascular size, indicating that BEH3 functions as a stabilizer of vascular stem cells. Genetic analysis revealed that BEH3 and BES1 perform opposite functions in the regulation of vascular stem cells and the differentiation of vascular cells in the context of the VISUAL system. At the biochemical level, BEH3 showed weak transcriptional repressor activity and functioned antagonistically to other BES/BZR members by competing for binding to the brassinosteroid response element. Furthermore, mathematical modeling suggested that the competitive relationship between BES/BZR homologs leads to the robust regulation of vascular stem cells.
Subject(s)
Arabidopsis Proteins/genetics , Arabidopsis/growth & development , Arabidopsis/genetics , DNA-Binding Proteins/genetics , Arabidopsis Proteins/metabolism , Brassinosteroids/metabolism , Cambium/genetics , DNA-Binding Proteins/metabolism , Data Visualization , Databases, Genetic , Gene Expression Profiling/methods , Gene Expression Regulation, Plant , Gene Regulatory Networks , Hypocotyl/genetics , Hypocotyl/growth & development , Mutation , Phloem/genetics , Phylogeny , Plants, Genetically Modified , Response Elements , Xylem/geneticsABSTRACT
Regulatory T cells (Tregs) play an important role in creating an immunosuppressive microenvironment in cancer tissues. However, the mechanisms by which Tregs are activated and suppress cancer immunity remain unclear. To elucidate these mechanisms, we performed a T cell receptor (TCR) repertoire analysis of Tregs and conventional T cells in peripheral blood, draining lymph nodes (DLNs), and cancer tissues of patients with head and neck squamous cell cancer (HNSCC). We found that the TCR repertoire was skewed in cancer tissue and metastatic DLNs (M-DLNs) compared with non-metastatic DLNs, and TCR repertoire similarities in Tregs and CD8+ T cells between M-DLNs and cancer tissue were high compared with those at other sites. These results suggest that Tregs and CD8+ T cells are activated in M-DLNs and cancer tissues by cancer antigens, such as neoantigens, and shared antigens and Tregs suppress CD8+ T cell function in a cancer antigen-specific manner in M-DLNs and cancer tissue. Moreover, M-DLNs might be a source of Tregs and CD8+ T cells recruited into the cancer tissue. Therefore, targeting Tregs in M-DLNs in an antigen-specific manner is expected to be a novel immunotherapeutic strategy for HNSCCs.
Subject(s)
CD8-Positive T-Lymphocytes , Head and Neck Neoplasms , Lymph Nodes , Squamous Cell Carcinoma of Head and Neck , T-Lymphocytes, Regulatory , T-Lymphocytes, Regulatory/immunology , Humans , Head and Neck Neoplasms/immunology , Head and Neck Neoplasms/pathology , Squamous Cell Carcinoma of Head and Neck/immunology , Squamous Cell Carcinoma of Head and Neck/pathology , Lymph Nodes/pathology , Lymph Nodes/immunology , CD8-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/pathology , Male , Tumor Microenvironment/immunology , Lymphatic Metastasis/pathology , Lymphatic Metastasis/immunology , Female , Middle Aged , Carcinoma, Squamous Cell/immunology , Carcinoma, Squamous Cell/pathology , Aged , Receptors, Antigen, T-Cell/immunologyABSTRACT
BACKGROUND: Cerebrovascular diseases in cancer patients significantly aggravate their condition and prognosis; therefore, prompt and accurate diagnosis and treatment are important. The purpose of this study was to investigate patient demographics, laboratory data, brain magnetic resonance imaging (MRI) findings, and prognosis among patients with stroke and cancer, especially cancer-associated ischemic stroke (CAIS). METHODS: We performed a retrospective, single-center study. We enrolled consecutive patients who had acute stroke and were admitted to our hospital between January 2011 and December 2021. We collected general demographic characteristics, cancer histopathological type, laboratory data, brain MRI findings, and prognosis data. RESULTS: Among 2040 patients with acute stroke, a total of 160 patients (7.8%) had active cancer. The types of strokes were cerebral infarction, cerebral hemorrhage, subarachnoid hemorrhage, and transient ischemic attack in 124, 25, 5, and 6 patients, respectively. Among the patients with ischemic stroke, there were 69 cases of CAIS. Pancreas and adenocarcinoma were the most frequent types of primary tumor and histopathology. Patients with adenocarcinoma and those with cerebral infarctions in both bilateral anterior and posterior cerebral circulation areas showed higher D-dimer levels. Pancreatic cancer and high plasma D-dimer levels were associated with poor survival rate. CONCLUSION: CAIS was seen more frequently in patients with pancreatic cancer and adenocarcinoma. Pancreatic cancer and high plasma D-dimer levels were potential factors of poor prognosis in patients with CAIS.
Subject(s)
Neoplasms , Humans , Male , Female , Retrospective Studies , Prognosis , Middle Aged , Aged , Neoplasms/complications , Magnetic Resonance Imaging , Stroke/diagnostic imaging , Stroke/complications , Stroke/etiology , Stroke/diagnosis , Ischemic Stroke/diagnostic imaging , Ischemic Stroke/complications , Adenocarcinoma/complications , Adenocarcinoma/diagnosis , Fibrin Fibrinogen Degradation Products/metabolism , Fibrin Fibrinogen Degradation Products/analysis , Pancreatic Neoplasms/complications , Aged, 80 and over , AdultABSTRACT
A new non-invasive screening profile has been realized that can aid in determining T-cell activation state at single-cell level. Production of activated T-cells with good specificity and stable proliferation is greatly beneficial for advancing adoptive immunotherapy as innate immunological cells are not effective in recognizing and eliminating cancer as expected. The screening method is realized by relating intracellular Ca2+ intensity and motility of T-cells interacting with APC (Antigen Presenting Cells) in a microfluidic chip. The system is tested using APC pulsed with OVA257-264 peptide and its modified affinities (N4, Q4, T4 and V4), and the T-cells from OT-1 mice. In addition, single cell RNA sequencing reveals the activation states of the cells and the clusters from the derived profiles can be indicative of the T-cell activation state. The presented system here can be versatile for a comprehensive application to proceed with T-cell-based immunotherapy and screen the antigen-specific T-cells with excellent efficiency and high proliferation.
Subject(s)
Microfluidics , T-Lymphocytes , Mice , Animals , Antigens , Antigen-Presenting Cells , Lymphocyte ActivationABSTRACT
OBJECTIVE: The present study investigated the relationships between the preoperative and operative findings of solitary fibrous tumour (SFT) and between preoperative findings and prognosis. METHODS: We reviewed 50 SFT patients treated at our musculoskeletal oncology hospital group. We analyzed preoperative clinical findings, particularly MRI imaging findings, and intraoperative information as well as the relationship between preoperative findings and outcomes. RESULTS: Mean age was 48.9 years and the mean follow-up was 51.8 months. Prior to surgery, needle biopsy was performed on 27 patients and open biopsy on 14. T2-weighted images showed a high signal intensity in 24 patients and heterogeneous signal intensity in 20. Tumours had polylobular contours in 17 patients and smooth and round contours in 27. Collateral feeding vessels were detected in 22 patients. Gd-enhanced MRI was performed on 23 patients, and showed 15 with homogeneous enhancement and 8 with heterogeneous enhancement. Surgical times were significantly longer in patients with a retroperitoneal origin, a tumour of 10 cm or more, and polylobular-type tumours. Intraoperative blood loss was significantly greater in patients with a retroperitoneal origin and heterogeneous Gd-MRI-enhanced tumours. In histopathological evaluations, surgical margins were positive in 12 patients. Local recurrence was observed in one patient. Distant metastasis was noted in eight patients, four of whom had pulmonary metastases. Positive surgical margins were more common in polylobular-type tumours. Distant metastases were more likely to appear in patients with observable collateral feeding vessels and heterogeneous Gd-MRI enhancement. CONCLUSION: The present results suggest that preoperative clinical findings in SFT patients predict longer surgical times and the risk of increased intraoperative blood loss. Moreover, the risk of a positive surgical margin and postoperative distant metastases may be predicted based on preoperative MRI.
Subject(s)
Blood Loss, Surgical , Solitary Fibrous Tumors , Humans , Middle Aged , Magnetic Resonance Imaging/methods , Margins of Excision , Multicenter Studies as Topic , Prognosis , Retrospective Studies , Solitary Fibrous Tumors/diagnostic imaging , Solitary Fibrous Tumors/surgery , Solitary Fibrous Tumors/pathologyABSTRACT
BACKGROUND: Rosai-Dorfman disease (RDD) involving the central nervous system (CNS) is rare and observed in 5% of all patients with extranodal RDD. According to a previous report, gross total resection is curative; however, we encountered a case of recurrence following gross total resection. We discuss our case and review previous reports on recurrent RDD. CASE DESCRIPTION: A 68-year-old woman came to the hospital complaining of left parietal mass. A tumor that had partially eroded the frontal bone was found. As the lesion was suspected to be malignant, we performed a total resection. Pathology results were indicative of an RDD. We did not prescribe adjuvant therapy because total resection was performed. However, after a year, abnormal accumulation in the left parietal bone was observed on FDG-PET. This was considered as recurrence, and re-excision was performed. Pathological assessments confirmed the recurrence of RDD. CONCLUSIONS: Our case demonstrated the recurrence of RDD following total resection. Future reports should assess these peculiarities. This will facilitate discussions on the risk factors and the effectiveness of treatment methods.
Subject(s)
Histiocytosis, Sinus , Female , Humans , Aged , Histiocytosis, Sinus/pathology , Positron-Emission TomographyABSTRACT
Preoperative intra-arterial chemoradiotherapy (IACRT) can improve the outcome and reduce the extent of surgery in patients with advanced oral cancer. However, the response to this regimen varies among patients, which may be related to the immune status of the tumor. We investigated the effects of proteins involved in tumor immunity on the outcomes of combined IACRT and surgery for oral cancer. We examined CD8 + and FoxP3 + tumor-infiltrating lymphocytes (TILs) and programmed death ligand 1 (PD-L1) expression on immune cells and tumor cells in pretreatment biopsy samples from 69 patients diagnosed with oral cancer treated with IACRT at our institution during 2000-2020. Patients with abundant CD8 + TILs had significantly better 5-year disease-specific survival (DSS) compared to that of patients with less infiltration of these cells (P = 0.016). Patients with higher FoxP3 + T-cells invasion had significantly better DSS compared to that of less FoxP3 (P = 0.005). Patients with high PD-L1 expression in tumor cells and immune cells had significantly better DSS than that of patients with low PD-L1 expression in these cells (P = 0.009 and P = 0.025, respectively). Collectively, these results suggest that the tumor immune microenvironment could affect outcomes of IACRT treatment in oral cancer.
Subject(s)
B7-H1 Antigen , Mouth Neoplasms , Humans , B7-H1 Antigen/metabolism , Chemoradiotherapy , Mouth Neoplasms/drug therapy , Forkhead Transcription Factors/metabolism , Tumor MicroenvironmentABSTRACT
A concise, modular synthesis of the novel antibiotic darobactin A is disclosed. The synthesis successfully forges the hallmark strained macrocyclic ring systems in a sequential fashion. Key transformations include two atroposelective Larock-based macrocyclizations, one of which proceeds with exquisite regioselectivity despite bearing an unprotected alkyne. The synthesis is designed with medicinal chemistry considerations in mind, appending key portions of the molecule at a late stage. Requisite unnatural amino acid building blocks are easily prepared in an enantiopure form using C-H activation and decarboxylative cross-coupling tactics.
Subject(s)
Alkynes , Amino Acids , Alkynes/chemistry , Cyclization , PhenylpropionatesABSTRACT
INTRODUCTION: Denosumab has been shown to be highly effective at suppressing the progression of giant cell tumor of bone (GCTB). However, recent studies have observed a potential increased risk of local recurrence after surgery following the use of denosumab, raising concerns on the use of this agent against GCTB in combination with surgery. METHODS: We retrospectively reviewed the medical records of 234 patients with GCTB who were surgically treated at multiple institutions from 1990 to 2017. Patient background, tumor characteristics, treatment methods, local recurrence-free survival rate, distant metastasis rate, oncologic outcome, and limb function at final follow-up were analyzed and compared between cases treated with and without denosumab. RESULTS: The 3-year local recurrence-free survival rate was significantly lower in patients who underwent preoperative denosumab therapy (35.3%) compared with those treated without denosumab (79.9%) (P < 0.001). Among patients who were preoperatively treated with denosumab, those who had a local recurrence all underwent curettage surgery. CONCLUSIONS: Preoperative denosumab therapy in combination with curettage surgery was significantly associated with an increased risk of local recurrence in Campanacci grade 3 tumors. Our data suggest that clinicians seeing GCTB patients should be aware to this increased risk when planning preoperative denosumab therapy.
Subject(s)
Bone Density Conservation Agents , Bone Neoplasms , Giant Cell Tumor of Bone , Bone Density Conservation Agents/adverse effects , Bone Density Conservation Agents/therapeutic use , Bone Neoplasms/drug therapy , Bone Neoplasms/pathology , Bone Neoplasms/surgery , Curettage/adverse effects , Denosumab/adverse effects , Denosumab/therapeutic use , Giant Cell Tumor of Bone/drug therapy , Giant Cell Tumor of Bone/pathology , Giant Cell Tumor of Bone/surgery , Humans , Neoplasm Recurrence, Local/pathology , Retrospective StudiesABSTRACT
Challenges in the selective manipulation of functional groups (chemoselectivity) in organic synthesis have historically been overcome either by using reagents/catalysts that tunably interact with a substrate or through modification to shield undesired sites of reactivity (protecting groups). Although electrochemistry offers precise redox control to achieve unique chemoselectivity, this approach often becomes challenging in the presence of multiple redox-active functionalities. Historically, electrosynthesis has been performed almost solely by using direct current (DC). In contrast, applying alternating current (AC) has been known to change reaction outcomes considerably on an analytical scale but has rarely been strategically exploited for use in complex preparative organic synthesis. Here we show how a square waveform employed to deliver electric current-rapid alternating polarity (rAP)-enables control over reaction outcomes in the chemoselective reduction of carbonyl compounds, one of the most widely used reaction manifolds. The reactivity observed cannot be recapitulated using DC electrolysis or chemical reagents. The synthetic value brought by this new method for controlling chemoselectivity is vividly demonstrated in the context of classical reactivity problems such as chiral auxiliary removal and cutting-edge medicinal chemistry topics such as the synthesis of PROTACs.
Subject(s)
Organic ChemicalsABSTRACT
The site-specific oxidation of strong C(sp3)-H bonds is of uncontested utility in organic synthesis. From simplifying access to metabolites and late-stage diversification of lead compounds to truncating retrosynthetic plans, there is a growing need for new reagents and methods for achieving such a transformation in both academic and industrial circles. One main drawback of current chemical reagents is the lack of diversity with regard to structure and reactivity that prevents a combinatorial approach for rapid screening to be employed. In that regard, directed evolution still holds the greatest promise for achieving complex C-H oxidations in a variety of complex settings. Herein we present a rationally designed platform that provides a step toward this challenge using N-ammonium ylides as electrochemically driven oxidants for site-specific, chemoselective C(sp3)-H oxidation. By taking a first-principles approach guided by computation, these new mediators were identified and rapidly expanded into a library using ubiquitous building blocks and trivial synthesis techniques. The ylide-based approach to C-H oxidation exhibits tunable selectivity that is often exclusive to this class of oxidants and can be applied to real-world problems in the agricultural and pharmaceutical sectors.
Subject(s)
Ammonium Compounds/chemistry , Electrochemical Techniques , Molecular Structure , Oxidation-ReductionABSTRACT
BACKGROUND: Although the unpredictable malignant behavior of solitary fibrous tumors (SFTs) has been recognized, the clinical features and prognosis of metastatic SFTs have not been well documented due to the extreme rarity of these cases. The aim of this study is to investigate the clinical features, prognostic factors, and optimal management of patients with metastatic SFTs. PATIENTS AND METHODS: Sixty patients with metastatic SFT were retrospectively reviewed. Univariate and multivariate analyses were performed to identify the factors associated with survival. Time to next treatment (TNT) was used to evaluate the effects of various chemotherapy regimens. RESULTS: A total of 34 male and 26 female patients (median age 55 years, range, 23-87 years) were included in the study. The median follow-up period after metastasis was 32 months (range 1-126 months). Tumor location and local recurrence were correlated with late metastasis. The 3- and 5-year overall survival rates were 72.7% and 49.2%, respectively. Primary tumor location, number of metastases, and metastasectomy were significantly associated with survival. Metastasectomy was the only significant variable on multivariate analysis. The TNT was significantly different among the various regimens. CONCLUSIONS: Patients with metastatic SFTs had relatively longer survival periods compared with those with other metastatic soft-tissue sarcomas. Tumor location and number of metastases was associated with survival. Surgical resection of the metastatic lesions offers the best chance of survival, however further studies are warranted to define patients who would benefit from metastasectomy, and the most effective chemotherapeutic regimen for patients with metastatic SFTs remains unknown.
Subject(s)
Neoplasm Recurrence, Local , Solitary Fibrous Tumors , Female , Humans , Japan , Male , Middle Aged , Prognosis , Retrospective Studies , Solitary Fibrous Tumors/surgeryABSTRACT
PURPOSE: Penetration enhancers are necessary to overcome a formidable barrier function of the stratum corneum in the development of topical formulations. Recently, non-lamella liquid crystal (NLLC)-forming lipids such as glycerol monooleate and phytantriol (PHY) are gaining increasing attention as a novel skin permeation enhancer. In the present study, fluorescein sodium (FL-Na) was used as a model hydrophilic drug, and acryl-base pressure-sensitive adhesive (PSA) tape containing NLLC forming lipids, mono-O-(5,9,13-trimethyl-4-tetradecenyl) glycerol ester (MGE) or PHY, was prepared to enhance drug permeation through the skin. METHODS: A PSA patch containing FL-Na was prepared by mixing FL-Na entrapped in NLLC and acrylic polymer. FL permeation through excised hairless rat skin, and also human skin, was investigated. Changes in lipid structure, folding/unfolding state of keratin in the stratum corneum, and penetration of MGE into the stratum corneum were investigated using confocal Raman microscopy. RESULTS: Enhanced FL permeation was observed by the application of a PSA patch containing MGE and PHY. Especially, dramatically enhancement effect was confirmed by 15% of MGE contained formulation. Penetration of MGE provided diminished orthorhombic crystal structure and a peak shift of the aliphatic CH3 vibration of keratin chains toward lower wavenumbers. CONCLUSION: The present results suggested that the formulation development by adding MGE may be useful for improving the skin permeation of mal-permeable drugs such as hydrophilic drugs.
Subject(s)
Drug Delivery Systems/instrumentation , Epidermis/metabolism , Glycerol/pharmacology , Skin Absorption/drug effects , Transdermal Patch , Adhesives/chemistry , Administration, Cutaneous , Animals , Epidermis/drug effects , Fluorescein/administration & dosage , Fluorescein/pharmacokinetics , Glycerol/analogs & derivatives , Glycerol/chemistry , Humans , Hydrophobic and Hydrophilic Interactions , Liquid Crystals/chemistry , Permeability/drug effects , RatsABSTRACT
A 37-year-old pregnant woman who had undergone three previous cesarean sections was diagnosed as having placenta percreta. We decided to perform cesarean hysterectomy with bilateral common iliac artery balloon occlusion (CIABO). The duration of surgery was 2 h and 2 min and total estimated blood loss was 2600 mL. Surgery was completed without any surgical complications, but the pulse oximeter waveform of the left leg became undetectable during surgery. We immediately performed angiography after closure of laparotomy and found abnormal pooling of contrast media at the left common iliac artery in the region in which the balloon was positioned. We made a diagnosis of left common iliac artery dissection caused by CIABO. We performed emergent revascularization by intravascular stenting. We conclude that CIABO can cause common iliac artery dissection by mechanical stimulation of the inflated balloon. Careful intraoperative evaluation of limb ischemia and preparation of intravascular treatment is needed for a safe procedure.
Subject(s)
Balloon Occlusion , Placenta Accreta , Adult , Balloon Occlusion/adverse effects , Blood Loss, Surgical , Dissection , Female , Humans , Hysterectomy , Iliac Artery/diagnostic imaging , Iliac Artery/surgery , Placenta Accreta/surgery , PregnancyABSTRACT
Here we report the improved Cyclo olefin polymer (COP) microfluidic chip and polymerase chain reaction (PCR) amplification system for point-of-care testing (POCT) in rapid detection of Carbapenem-resistant Enterobacteriaceae (CRE). The PCR solution and thermal cycling is controlled by the relative gravitational acceleration (7G) only and is expected to pose minimal problem in operation by non-expert users. Detection is based on identifying the presence of carbapenemase encoding gene through the corresponding fluorescence signal after amplification. For preliminary tests, the device has been demonstrated to detect blaIMP-6 from patients stool samples. From the prepared samples, 96.4 fg/µL was detected with good certainty within 15 min (~106 thermocycles,) which is significantly faster than the conventional culture plate method. Moreover, the device is expected to detect other target genes in parallel as determination of the presence of blaNDM-1 and blaOXA-23 from control samples has also been demonstrated. With the rising threat of drug-resistant bacteria in global healthcare, this technology can greatly aid the health sector by enabling the appropriate use of antibiotics, accelerating the treatment of carriers, and suppressing the spread.
Subject(s)
Convection , Pharmaceutical Preparations , Polymerase Chain Reaction , Acceleration , Anti-Bacterial Agents/therapeutic use , Bacterial Proteins , Humans , Microbial Sensitivity TestsABSTRACT
A mild and chemoselective method for the thioacylation of amines using α-keto acids and elemental sulfur has been developed. The key to the success of this transformation is the nucleophilic activation of elemental sulfur by thiols such as 1-dodecanethiol. A variety of functional groups, including unprotected hydroxyl, carboxyl, amide, sulfide, and tertiary amine moieties, are tolerated under the applied reaction conditions. To demonstrate the advantages of this method compared with conventional O-S exchange reactions using Lawesson's reagent or P2S5, thioamide moieties were introduced site-specifically into biologically active compounds.
ABSTRACT
Lactic acidosis is a common condition observed in a patient after cardiac surgery. It is important to identify the pathogenesis of lactic acidosis since the delay of an appropriate treatment leads to high mortality. Metformin overdose has been known as a risk of lactic acidosis, and previous reports have demonstrated that continuous renal replacement therapy(CRRT) is effective. However, it has yet to be known if metformin-related lactic acidosis after cardiac surgery is treatable with CRRT. We, herein, report a case of 64-year-old diabetic male who had been on metformin treatment until 1 day before surgery. He presented lactic acidosis postoperatively and was successfully treated with CRRT. This case suggests that it is necessary to discontinue metformin no later than 2 days before surgery and that CRRT is of use for perioperative lactic acidosis in a patient on metformin.
Subject(s)
Acidosis, Lactic , Cardiac Surgical Procedures , Metformin , Continuous Renal Replacement Therapy , Humans , Hypoglycemic Agents , Male , Middle Aged , PatientsABSTRACT
Cell differentiation is a complex process involving multiple steps, from initial cell fate specification to final differentiation. Procambial/cambial cells, which act as vascular stem cells, differentiate into both xylem and phloem cells during vascular development. Recent studies have identified regulatory cascades for xylem differentiation. However, the molecular mechanism underlying phloem differentiation is largely unexplored due to technical challenges. Here, we established an ectopic induction system for phloem differentiation named Vascular Cell Induction Culture System Using Arabidopsis Leaves (VISUAL). Our results verified similarities between VISUAL-induced Arabidopsis thaliana phloem cells and in vivo sieve elements. We performed network analysis using transcriptome data with VISUAL to dissect the processes underlying phloem differentiation, eventually identifying a factor involved in the regulation of the master transcription factor gene APL Thus, our culture system opens up new avenues not only for genetic studies of phloem differentiation, but also for future investigations of multidirectional differentiation from vascular stem cells.
Subject(s)
Arabidopsis/cytology , Arabidopsis/metabolism , Plant Leaves/cytology , Plant Leaves/metabolism , Arabidopsis Proteins/metabolism , Cell Differentiation/genetics , Cell Differentiation/physiology , Gene Expression Regulation, Plant/genetics , Gene Expression Regulation, Plant/physiology , Phloem/cytology , Phloem/metabolism , Xylem/cytology , Xylem/metabolismABSTRACT
The reactions of thioamides with ortho-nitro-substituted iodonium ylides proceeded under mild conditions to give enaminones or thiazoles, depending on the iodonium ylide used. This protocol allowed the use of protic solvents, including aqueous solutions, and therefore coupling reactions with complex molecules such as peptides or steroids were possible. A mild and efficient method for the synthesis of various iodonium ylides was established. DFT calculations suggested that the halogen bonding between a thioamide and iodonium ylide was important in this chemoselective coupling reaction. The potential use of enaminones conjugated with pharmaceuticals as prodrugs was also demonstrated.
ABSTRACT
Vascular development is a good model for studying cell differentiation in plants. Two conductive tissues, the xylem and phloem, are derived from common stem cells known as procambial/cambial cells. Glycogen synthase kinase 3 proteins (GSK3s) play crucial roles in maintaining procambial/cambial cells by suppressing their differentiation into xylem or phloem cells. We previously designed an in vitro culture system for analyzing vascular cell differentiation named VISUAL (Vascular cell Induction culture System Using Arabidopsis Leaves). Using this system, we found that the transcription factor BRI1-EMS-SUPPRESSOR 1 (BES1) functions as a downstream target of GSK3s during xylem differentiation. However, the function of BES1 in vascular development remains largely unknown. Here, we found that, in addition to xylem differentiation, BES1 positively regulates phloem differentiation downstream of GSK3s. Transcriptome analysis using VISUAL confirmed that BES1 promotes bi-directional differentiation of procambial cells into xylem and phloem cells. Genetic analysis of loss-of-function mutants newly generated using the CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9) system revealed that BRASSINAZOLE RESISTANT 1 (BZR1), the closest homolog of BES1, functions in vascular development redundantly with BES1. Notably, BZR1 has a weaker impact on vascular cell differentiation than BES1, suggesting that they contribute differentially to this process. In conclusion, our findings indicate that BES1 and BZR1 are key regulators of both xylem and phloem cell differentiation from vascular stem cells.