The TELOMERE REPEAT BINDING proteins TRB4 and TRB5 function as transcriptional activators of PRC2-controlled genes to regulate plant development

Plant-specific transcriptional regulators called TELOMERE REPEAT BINDING proteins (TRBs) combine two DNA-binding domains, the GH1 domain, which binds to linker DNA and is shared with H1 histones, and the Myb/SANT domain, which specifically recognizes the telobox DNA-binding site motif. TRB1, TRB2, and TRB3 proteins recruit Polycomb group complex 2 (PRC2) to deposit H3K27me3 and JMJ14 to remove H3K4me3 at gene promoters containing telobox motifs to repress transcription. Here, we demonstrate that TRB4 and TRB5, two related paralogs belonging to a separate TRB clade conserved in spermatophytes, regulate the transcription of several hundred genes involved in developmental responses to environmental cues. TRB4 binds to several thousand sites in the genome, mainly at transcription start sites and promoter regions of transcriptionally active and H3K4me3-marked genes, but, unlike TRB1, it is not enriched at H3K27me3-marked gene bodies. However, TRB4 can physically interact with the catalytic components of PRC2, SWINGER, and CURLY LEAF (CLF). Unexpectedly, we show that TRB4 and TRB5 are required for distinctive phenotypic traits observed in clf mutant plants and thus function as transcriptional activators of several hundred CLF-controlled genes, including key flowering genes. We further demonstrate that TRB4 shares multiple target genes with TRB1 and physically and genetically interacts with members of both TRB clades. Collectively, these results reveal that TRB proteins engage in both positive and negative interactions with other members of the family to regulate plant development through both PRC2-dependent and -independent mechanisms.

The UBP5 histone H2A deubiquitinase counteracts PRCs-mediated repression to regulate Arabidopsis development

Polycomb Repressive Complexes (PRCs) control gene expression through the incorporation of H2Aub and H3K27me3. In recent years, there is increasing evidence of the complexity of PRCs' interaction networks and the interplay of these interactors with PRCs in epigenome reshaping, which is fundamental to understand gene regulatory mechanisms. Here, we identified UBIQUITIN SPECIFIC PROTEASE 5 (UBP5) as a chromatin player able to counteract the deposition of the two PRCs' epigenetic hallmarks in Arabidopsis thaliana. We demonstrated that UBP5 is a plant developmental regulator based on functional analyses of ubp5-CRISPR Cas9 mutant plants. UBP5 promotes H2A monoubiquitination erasure, leading to transcriptional de-repression. Furthermore, preferential association of UBP5 at PRC2 recruiting motifs and local H3K27me3 gaining in ubp5 mutant plants suggest the existence of functional interplays between UBP5 and PRC2 in regulating epigenome dynamics. In summary, acting as an antagonist of the pivotal epigenetic repressive marks H2Aub and H3K27me3, UBP5 provides novel insights to disentangle the complex regulation of PRCs' activities.

Histone H1 protects telomeric repeats from H3K27me3 invasion in Arabidopsis

While the pivotal role of linker histone H1 in shaping nucleosome organization is well established, its functional interplays with chromatin factors along the epigenome are just starting to emerge. Here we show that, in Arabidopsis, as in mammals, H1 occupies Polycomb Repressive Complex 2 (PRC2) target genes where it favors chromatin condensation and H3K27me3 deposition. We further show that, contrasting with its conserved function in PRC2 activation at genes, H1 selectively prevents H3K27me3 accumulation at telomeres and large pericentromeric interstitial telomeric repeat (ITR) domains by restricting DNA accessibility to Telomere Repeat Binding (TRB) proteins, a group of H1-related Myb factors mediating PRC2 cis recruitment. This study provides a mechanistic framework by which H1 avoids the formation of gigantic H3K27me3-rich domains at telomeric sequences and contributes to safeguard nucleus architecture.

Open retropubic radical prostatectomy; still a well-established surgical technique for prostate cancer management

INTRODUCTION

The surgical treatment options for prostate cancer have changed rapidly, given the expansion of robotics. However, open retropubic radical prostatectomy (ORP) will continue to be performed in areas with financial limitations or with limited access to robotics. The purpose of this study was to determine the long-term oncological outcomes, to categorize complication rates and to examine the early continence rates in patients treated with ORP.

METHODS

We identified all patients who underwent ORP at our institution between 2000 and 2020. A standardized pad test was used to determine the early continence rates upon catheter removal, the late continence around a year after surgery was determined by the number of pads per day. The Clavien-Dindo classification was used to report the complication rates. The biochemical recurrence (BCR)-free survival and overall survival (OS) rates were defined using the Kaplan-Meier method and log-rank analysis. Multivariable Cox-regression models were used to test the effect of different factors on biochemical recurrence.

RESULTS

We analyzed 1095 patients. The median follow-up was 93.4 months. An overall 10-year BCR-free survival and OS of 73% and 82% respectively was found. A complication rate for Clavien Dindo≥3 was seen in 4.8% of patients. The early continence rate was 81.4% and the late continence 89,1%. Preoperative PSA level, Gleason score sum, pT stage, lymph node status, and surgical margin status were independent predictors of BCR (p<0.001, 95% CI). Limitations include retrospective and single center study design.

CONCLUSIONS

ORP is a surgical procedure that provides excellent oncological- and early continence-rates.

OS03.7.A Clinical characteristics, treatment and long-term outcome of patients with brain metastases from thyroid cancer - an analysis of the Vienna Brain Metastasis Registry

Background

The incidence of brain metastases (BM) in patients with thyroid cancer (TC) depends on the histological subtype. About 1% of patients with differentiated (DTC), 3% with medullary (MTC) and up to 10% with anaplastic thyroid cancer (ATC) develop BM. The diagnosis of BM drastically worsens the prognosis of TC. Given the rare incidence, little is known about the presentation and outcome of this cohort.

Material and Methods

Patients with a histologically verified diagnosis of TC and BM were identified from the Vienna Brain Metastasis Registry, a comprehensive database managed by the Division of Oncology, Medical University of Vienna, including patients with cerebral metastasis since 1990. Data were obtained from medical records comprising clinicopathological features, treatment, BM-specific characteristics and outcome.

Results

20/6074 patients included in the registry had a diagnosis of TC and radiologically verified BM. 13/20 (65%) were female and the median age at diagnosis of TC and manifestation of BM was 56 years (range 21-75) and 68 years (range 45-75), respectively. In terms of histology, 18/20 (90%) had DTC, one MTC and one ATC. Interestingly, 10/18 DTC presented with follicular histology which underlines the more aggressive course of this rare subtype. 6/20 (30%) had BM at primary diagnosis (DTC n=5, ATC n=1), while the remaining developed BM during follow-up. The median time to diagnosis of BM was 2.6 years for DTC (range 0-42), 22 years in the MTC patient and 2 months for ATC. Regarding BM-specific characteristics, all but one patient had symptoms due to BM (neurological deficits n=11, increased intracranial pressure n=5, seizures n=3). Most patients (13/20) had a singular BM, commonly located in the left hemisphere (8/13), and only one had more than three BMs. Upfront treatment for BM was local therapy (resection n=9, stereotactic radiosurgery n=7, whole brain radiotherapy n=3); one patient received supportive care only. The median overall survival (mOS) from diagnosis of TC was 6 years for DTC (range 2.5 months-42 years), 33 years for the MTC and 9 months for the ATC. The mOS from diagnosis of BM was 14 months for DTC (1.8 months-16 years), 22 years for the MTC and 3 months for the ATC.

Conclusion

Few patients with TC develop BM, which present commonly as single lesion. While in general BM constitute a poor prognostic factor, individual patients experience long-term survival following local therapy. More information about the optimal management of BM in TC is needed to enable guideline recommendations.

Experimental verification of principal losses in a regulatory particulate matter emissions sampling system for aircraft turbine engines

A sampling system for measuring emissions of nonvolatile particulate matter (nvPM) from aircraft gas turbine engines has been developed to replace the use of smoke number and is used for international regulatory purposes. This sampling system can be up to 35 m in length. The sampling system length in addition to the volatile particle remover (VPR) and other sampling system components lead to substantial particle losses, which are a function of the particle size distribution, ranging from 50 to 90% for particle number concentrations and 10-50% for particle mass concentrations. The particle size distribution is dependent on engine technology, operating point, and fuel composition. Any nvPM emissions measurement bias caused by the sampling system will lead to unrepresentative emissions measurements which limit the method as a universal metric. Hence, a method to estimate size dependent sampling system losses using the system parameters and the measured mass and number concentrations was also developed (SAE 2017; SAE 2019). An assessment of the particle losses in two principal components used in ARP6481 (SAE 2019) was conducted during the VAriable Response In Aircraft nvPM Testing (VARIAnT) 2 campaign. Measurements were made on the 25-meter sample line portion of the system using multiple, well characterized particle sizing instruments to obtain the penetration efficiencies. An agreement of ± 15% was obtained between the measured and the ARP6481 method penetrations for the 25-meter sample line portion of the system. Measurements of VPR penetration efficiency were also made to verify its performance for aviation nvPM number. The research also demonstrated the difficulty of making system loss measurements and substantiates the E-31 decision to predict rather than measure system losses.

DET1-mediated COP1 regulation avoids HY5 activity over second-site gene targets to tune plant photomorphogenesis

DE-ETIOLATED 1 (DET1) and CONSTITUTIVE PHOTOMORPHOGENESIS 1 (COP1) are two essential repressors of Arabidopsis photomorphogenesis. These proteins can associate with CULLIN4 to form independent CRL4-based E3 ubiquitin ligases that mediate the degradation of several photomorphogenic transcription factors, including ELONGATED HYPOCOTYL 5 (HY5), thereby controlling multiple gene-regulatory networks. Despite extensive biochemical and genetic analyses of their multi-subunit complexes, the functional links between DET1 and COP1 have long remained elusive. Here, we report that DET1 associates with COP1 in vivo, enhances COP1-HY5 interaction, and promotes COP1 destabilization in a process that dampens HY5 protein abundance. By regulating its accumulation, DET1 avoids HY5 association with hundreds of second-site genomic loci, which are also frequently targeted by the skotomorphogenic transcription factor PHYTOCHROME-INTERACTING FACTOR 3. Accordingly, ectopic HY5 chromatin enrichment favors local gene repression and can trigger fusca-like phenotypes. This study therefore shows that DET1-mediated regulation of COP1 stability tunes down the HY5 cistrome, avoiding hyper-photomorphogenic responses that might compromise plant viability.

DET1-mediated COP1 regulation avoids HY5 activity over second-site gene targets to tune plant photomorphogenesis

DE-ETIOLATED 1 (DET1) and CONSTITUTIVE PHOTOMORPHOGENESIS 1 (COP1) are two essential repressors of Arabidopsis photomorphogenesis. These proteins can associate with CULLIN4 to form independent CRL4-based E3 ubiquitin ligases that mediate the degradation of several photomorphogenic transcription factors, including ELONGATED HYPOCOTYL 5 (HY5), thereby controlling multiple gene-regulatory networks. Despite extensive biochemical and genetic analyses of their multi-subunit complexes, the functional links between DET1 and COP1 have long remained elusive. Here, we report that DET1 associates with COP1 in vivo, enhances COP1-HY5 interaction, and promotes COP1 destabilization in a process that dampens HY5 protein abundance. By regulating its accumulation, DET1 avoids HY5 association with hundreds of second-site genomic loci, which are also frequently targeted by the skotomorphogenic transcription factor PHYTOCHROME-INTERACTING FACTOR 3. Accordingly, ectopic HY5 chromatin enrichment favors local gene repression and can trigger fusca-like phenotypes. This study therefore shows that DET1-mediated regulation of COP1 stability tunes down the HY5 cistrome, avoiding hyper-photomorphogenic responses that might compromise plant viability.

Synthesis and cytotoxic evaluation of benzoxazole/benzothiazole-2-imino-coumarin hybrids and their coumarin analogues as potential anticancer agents

Two series of 2-imino-coumarin based hybrids: 3-(benzoxazol-2-yl)-2H-chromen-2-imines 3-9 (series A-I) and 3-(benzothiazol-2-yl)-2H-chromen-2-imines 10-16 (series A-II), as well as their coumarin analogues: 3-(benzoxazol-2-yl)-2H-chromen-2-ones 17-21 (series B-I) and 3-(benzothiazol-2-yl)-2H-chromen-2-ones 22-28 (series B-II) were prepared as potential antitumor agents. The in vitro cytotoxic potency of the synthesized compounds was evaluated against five human cancer cell lines: DAN-G, A-427, LCLC-103H, RT-4 and SISO, and relationships between structure and anticancer activity are discussed. Among the compounds tested, 3-(benzo[d] oxazol-2-yl)-N,N-diethyl-2-imino-2H-chromen-7-amine (6, series A-I) and 3-(benzo[d]thiazol-2-yl)-6-fluoro-2H-chromen-2-one (26, series B-II) exhibited the most potent cytotoxic activity with IC₅₀ values ranging from <0.01 μM to 1.1 μM. In particular, compound 6 demonstrated remarkable cytotoxicity against the A-427 ovarian cancer, the lung cancer LCLC-103H, urinary bladder cancer RT-4 and cervical cancer SISO cell lines with IC₅₀ <0.01-0.30μM, inducing apoptosis in two representative cell lines.

Effect of zileuton on osteoporotic bone and its healing, expression of bone, and brain genes in rats

Estrogen deficiency and aging are associated with osteoporosis, impaired bone healing, and lower cognitive performance. Close functional and physical connections occur between bone and the central nervous system. An anti-inflammatory drug, zileuton (which is an inhibitor of arachidonate 5-lipoxygenase), is known to have a positive effect on bone tissue repair and brain ischemia. We studied the effect of zileuton on osteopenic bone and its healing and on the genes considered to be crucial for the cross talks between bone and brain. Three-month-old Sprague-Dawley rats were ovariectomized or left untreated. After 8 wk, bilateral metaphyseal tibia osteotomy with plate osteosynthesis was performed in all rats. Ovariectomized rats were fed with food containing zileuton (1, 10, or 100 mg/kg body wt) for 5 wk. In tibiae, bone volume, callus and cortical volume, and gene expression of osteocalcin and alkaline phosphatase were enhanced by zileuton (10 or 100 mg); biomechanical properties and bone density were not changed. In femur, zileuton enlarged cortical volume distal and trabecular volume proximal, decreasing their density. The expression level of brain Sema3a, known to regulate bone mass positively, was downregulated after ovariectomy. In contrast, bone Sema4d, a negative regulator of bone mass, was upregulated in the tibia callus after ovariectomy, whereas zileuton treatment (10 or 100 mg) resulted in reverse effects. Here, we describe for the first time the expression of Rbbp4 mRNA and its increase in tibia after ovariectomy. Zileuton caused downregulation of Rbbp4 in the hippocampus and had an effect on bone healing, changed the expression of genes involved in cross talk between bones and brain, and may be a potent drug for further examination in estrogen deficiency-related dysfunction(s). NEW & NOTEWORTHY Zileuton, a 5-lipoxygenase inhibitor, increased bone volume, callus and cortical volume in osteotomized tibia, and trabecular and cortical volume in femur. Although the expression of Sema3a (positively regulating bone mass) in brain was downregulated and Sema4d (negatively regulating bone mass) was upregulated in tibia callus after ovariectomy, zileuton could counteract these effects. Rbbp4 (involved in age-related memory loss) was increased in tibia callus after ovariectomy.

[Epidermal aging and anti-aging strategies]

Epithelial senescence is a complex process depending on intrinsic as well as extrinsic factors (e.g., UV or IR light, tobacco smoke) and must be seen in the context of the aging process especially of the corium and the subcutis. Morphological alterations become apparent in the form of epithelial atrophy, structural changes within the basal membrane, and a decrease in cell count of melanocytes and Langerhans cells. Signs of cellular senescence are reduced proliferation of keratinocytes, cumulation of dysplastic keratinocytes, various mutations (e.g., c-Fos/c-Jun, STAT3, FoxO1), as well as multiple lipid or amino acid metabolic aberrations (e.g., production of advanced glycation endproducts). This causes functional changes within the physical (lipid deficiency, water distribution dysfunction, lack of hygroscopic substances), chemical (pH conditions, oxygen radicals), and immunological barrier. Prophylactically, barrier-protective care products, antioxidant substances (e.g., vitamin C, B3, E, polyphenols, flavonoids), sunscreen products/measurements, and retinoids are used. For correcting alterations in aged epidermis, chemical peelings (fruit acids, β-hydroxy acid, trichloroacetic acid, phenolic compounds), non-ablative (IPL, PDL, Nd:YAG) as well as ablative (CO2, Erbium-YAG) light-assisted methods are used.

Efficacy and tolerability of pale sulfonated shale oil cream 4% in the treatment of mild to moderate atopic eczema in children: a multicentre, randomized vehicle-controlled trial

BACKGROUND

Reports on controlled trials on the efficacy and tolerability of sulfonated shale oils in atopic eczema are not available so far. The aim of this study was to investigate whether topically applied, specially prepared pale sulfonated shale oil (PSSO) cream is capable of improving symptoms/signs of mild to moderate atopic eczema in children more efficaciously than a corresponding vehicle cream.

PATIENTS AND METHODS

A total of 99 children suffering from mild to moderate atopic eczema were enrolled in this multicentre, randomized, vehicle-controlled study. Verum or vehicle cream was applied to the affected skin area three times a day over 4 weeks. As the primary outcome parameter served the reduction of the total score after 4 weeks of treatment, compared with the initial examination. Secondary outcome parameters were addressed as well. Tolerability was judged by investigators and patients/parents, and adverse events were documented.

RESULTS

After 4 weeks of treatment, the total score declined from 13.4 ± 3.7 to 4.5 ± 7.4 score points in the verum group and from 13.0 ± 3.1 to 11.7 ± 8.6 score points in the vehicle group (P < 0.0001). The superiority of verum regarding total score was already apparent after a treatment period of 1 week (reduction by 5.6 ± 4.3 vs. 1.3 ± 5.9 score points; P < 0.0001). Tolerability was found superior at the end of the treatment in the verum when compared with the control group--both by investigators (P < 0.0001) and patients/parents (P = 0.0051).

CONCLUSION

Pale sulfonated shale oil cream 4% is capable to treat mild to moderate atopic eczema in children more efficaciously than vehicle and is well tolerated. PSSO thus represents a valuable addition to our therapeutic armamentarium. PSSO should be considered in particular when valid alternatives for topical glucocorticoids are sought for.

Overexpression/enhanced kinase activity of BCR/ABL and altered expression of Notch1 induced acute leukemia in p210BCR/ABL transgenic mice

Chronic myelogenous leukemia (CML) is a hematopoietic disorder, which begins as indolent chronic phase but inevitably progresses to fatal blast crisis. p210BCR/ABL, a constitutively active tyrosine kinase, is responsible for disease initiation but molecular mechanism(s) underlying disease evolution remains largely unknown. To explore this process, we employed retroviral insertional mutagenesis to CML-exhibiting p210BCR/ABL transgenic mice (Tg). Virus infection induced acute lymphoblastic leukemia (ALL) in p210BCR/ABL Tg with a higher frequency and in a shorter latency than wild-type littermates, and inverse PCR detected two retrovirus common integration sites (CISs) in p210BCR/ABL Tg tumors. Interestingly, one CIS was the transgene itself, where retrovirus integrations induced upregulation of p210BCR/ABL and production of truncated BCR/ABL with an enhanced kinase activity. Another CIS was Notch1 gene, where retrovirus integrations resulted in overexpression of Notch1 and generation of Notch1 lacking the C-terminal region (Notch1DeltaC) associated with stable expression of its activated product, C-terminal-truncated Notch intracellular domain (NICD Delta C). In addition, generation of Tg for both p210BCR/ABL and Notch1DeltaC developed ALL in a shortened period with Stat5 activation, demonstrating the cooperative oncogenicity of Notch1DeltaC/NICD Delta C with p210BCR/ABL involving Stat5-mediated pathway. These results demonstrated that overexpression/enhanced kinase activity of BCR/ABL and altered expression of Notch1 induces acute leukemia in a transgenic model for CML.