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To assess in individuals with traumatic spinal cord injury (TSCI) the relationship between mortality and need for ICU and early magnetic resonance imaging (MRI), analyzing spinal parenchymal alterations, disruption of vertebral ligaments (DVL) and spinal cord compression (SCC).Retrospective study.Third-level hospital, Spinal Cord Injury Unit and ICU.Individuals with acute TSCI between 2010 and 2019.Analysis of MRI performed in the first 72 h.Admission to ICU and mortality.269 cases collected. The pattern that demonstrated higher mortality was cord hemorrhage (16.7%) for 12.5% ​​of single-level edema and 6.5% of multilevel edema (p = 0.125). The same happened with ICU admissions: 69.0% in hemorrhage, 60.2% in multilevel edema and 46.3% in short edema (p = 0.018). Analyzing CCM, mortality was 13.4% with 59.2% of ICU admissions, for 2.2% and 42.2% of individuals without cord compression (p = 0.020 and p = 0.003). The figures of death and ICU admission among cord injuries with DVL were 15.0% and 67.3%, for 6.2% and 44.4% of the individuals without DLV (p 0.001 and p = 0.013).The presence of spinal cord hemorrhage, SCC and DVL was associated with a higher admission in ICU. A significant increase in mortality was observed in cases with SCC and DVL.

[Abstract] Objectives: To analyze the relationship between neurological progression following traumatic spinal cord injury and Spinal Cord Compression (SCC) and Spinal Ligamentous Injury (LI) by magnetic resonance imaging. Design: Retrospective observational study. Setting: Spinal Cord Injury Unit (A Coruña, Spain). Participants: Patients were admitted for traumatic spinal cord injury between January 2010 and December 2018 with a magnetic resonance imaging examination performed during the acute phase. Intervention: Evaluation of SCC and LI by magnetic resonance imaging. Outcome measures: Comparisons between neurological examination at admission and discharge were made, assessing ASIA Impairment Scale (AIS) grade and motor score. Results: Data from 296 patients were collected. A relationship between SCC and LI and complete injuries were found (P < 0.001). Improvement of the AIS grade was observed in 31.6% of patients with SCC and 31.3% with LI versus 42.7% and 37.8% of subjects without these complications, respectively. Regarding motor score, patients with SCC had lower mean values at the beginning (46.9 ± 26.8 versus 61.1 ± 29.9 in the control group, P < 0.001), as well as less improvement when assessed by the percentage of change (35.1 ± 37.5% versus 49.4 ± 38.1% in the control group, P = 0.010). Similar results were obtained in cases with LI: mean motor score at admission was 45.9 ± 26.7 versus 54.9 ± 29.4 in the control group (P = 0.014) and the percentage of change was 28.5 ± 37.1% in comparison to 46.0 ± 37.5% (P = 0.001) in the controls. Conclusions: There is a relationship between SCC and LI and complete spinal cord injury. This patient population has lower possibilities of improving their AIS grade and motor score.

Bioactive peptides are key molecules in health and medicine. Deep learning holds a big promise for the discovery and design of bioactive peptides. Yet, suitable experimental approaches are required to validate candidates in high throughput and at low cost. Here, we established a cell- free protein synthesis (CFPS) pipeline for the rapid and inexpensive production of antimicrobial peptides (AMPs) directly from DNA templates. To validate our platform, we used deep learning to design thousands of AMPs de novo. Using computational methods, we prioritized 500 candidates that we produced and screened with our CFPS pipeline. We identified 30 functional AMPs, which we characterized further through molecular dynamics simulations, antimicrobial activity and toxicity. Notably, six de novo-AMPs feature broad-spectrum activity against multidrug-resistant pathogens and do not develop bacterial resistance. Our work demonstrates the potential of CFPS for production and testing of bioactive peptides within less than 24 hours and

Inhibition of protein-protein interactions (PPIs) via designed peptides is an effective strategy to interfere with their biological functions. The Elongin BC heterodimer (ELOB/C) is involved in transcription elongation and protein turnover by PPIs that involve the so-called BC-box. ELOB and ELOC are commonly upregulated in cancer and essential for cancer cell growth, making them attractive drug targets. However, no strategy has been established to inhibit their functions in cells, so far. Here, we report a peptide that mimics a high-affinity BC-box and tightly binds to the ELOB/C dimer (kD= 0.45 ± 0.03 nM). Our peptide blocks the association of ELOB/C with its interaction partners, both in vitro and in the cellular environment. Cancer cells treated with this peptide inhibitor show decreased cell viability, altered cell cycle and increased apoptosis. Therefore, our work proposes that blocking the BC-box binding pocket of ELOB/C is a feasible strategy to impair the function of the ELOB/C heterodimer and inhibit cancer cell growth. Our peptide inhibitor promises novel mechanistic insights into the biological function of the ELOB/C dimer and offers a starting point for therapeutics linked to ELOB/C dysfunction.

Manipulation of RNA splicing machinery has emerged as a drug modality. Here, we illustrate the potential of this novel paradigm to correct aberrant splicing events focused on the recent therapeutic advances in spinal muscular atrophy (SMA). SMA is an incurable neuromuscular disorder and at present the primary genetic cause of early infant death. This Review summarizes the exciting journey from the first reported SMA cases to the currently approved splicing-switching treatments, i.e., antisense oligonucleotides and small-molecule modifiers. We emphasize both chemical structures and molecular bases for recognition. We briefly discuss the advantages and disadvantages of these treatments and include the remaining challenges and future directions. Finally, we also predict that these success stories will contribute to further therapies for human diseases by RNA-splicing control.

Cytoreductive surgery (CRS) in combination with hyperthermic intraperitoneal chemotherapy (HIPEC) is an option in advanced peritoneal sarcomatosis. Nevertheless, CRS and HIPEC are not successful in all patients. An enhancement of HIPEC using photodynamic therapy (PDT) might be beneficial. Therefore, a combination of the photosensitizer hypericin (HYP) with HIPEC was evaluated in an animal model.An established HIPEC animal model for rhabdomyosarcoma (NOD/LtSz-scid IL2Rγnullmice, n = 80) was used. All groups received HYP (100 μg/200 μl) intraperitoneally with and without cisplatin-based (30 or 60 mg/mHYP uptake was detected even in smallest tumor nodes (1 mm) with improved tumor detection during PDD (PCI with PDD vs. PCI without PDD: 8.5 vs. 7, p .001***). Apoptotic effects after PDT without HIPEC were limited to the tumor surface, whereas PDT after HIPEC (60 mg/mHYP as fluorescent photosensitizer offers an intraoperative diagnostic advantage detecting intraperitoneal tumor dissemination. The combination of HYP and cisplatin-based HIPEC was feasible in vivo, showing enhanced effects on tumor proliferation and apoptosis induction across the tumor surface. Further studies combining HYP and HIPEC will follow to establish a clinical application.

Photodynamic therapy (PDT) leads to cancer remission via the production of cytotoxic species under photosensitizer (PS) irradiation. However, concomitant damage and dark toxicity can both hinder its use. With this in mind, we have implemented a versatile peptide‐based platform of bioorthogonally activatable BODIPY‐tetrazine PSs. Confocal microscopy and phototoxicity studies demonstrated that the incorporation of the PS, as a bifunctional module, into a peptide enabled spatial and conditional control of singlet oxygen (1O2) generation. Comparing subcellular distribution, PS confined in the cytoplasmic membrane achieved the highest toxicities (IC50=0.096±0.003 μm) after activation and without apparent dark toxicity. Our tunable approach will inspire novel probes towards smart PDT., Modular peptide‐based platform for organelle‐confinement of the photodynamic effect. We report a general approach capable of directing the bioorthogonal activation of tetrazine‐BODIPY photosensitizers to specific subcellular organelles.

The complexity of the world’s current grand challenges demands interdisciplinary approaches. The education of future scientists must cross the silos of the traditional disciplines; however, there i...

[Abstract] Study design: Retrospective observational study. Objectives: Assess the relationship between Magnetic Resonance (MR) image patterns and neurological recovery in patients with Traumatic Spinal Cord Injury (TSCI). Setting: Spinal cord injury unit in Spain. Methods: Patients admitted for acute TSCI between January 2010 and December 2018 with a MR exam performed in the acute phase were selected. Five patterns were established: normal, single-level edema, multilevel edema, hemorrhage, and spinal cord transection. Comparisons between the ASIA Injury Severity (AIS) score and Motor Index (MI) at admission and at discharge were made. Results: Collected 296 patients. Normal and cord transection patterns were excluded due to the low number of cases. Single-level edema pattern was primarily observed in cases with incomplete injuries, hemorrhage pattern in complete injuries, and multilevel edema pattern at similar percentages in complete and incomplete lesions. Improvement of the AIS score was found in 40.9% of single-level edema, 20.2% of multilevel edema, and 19.0% of hemorrhage (p = 0.042) patterns. By excluding the AIS grade D from the analyses, the figures increased to 70.3%, 52.2%, and 19.4% respectively (p < 0.001). This significant relationship was confirmed by multivariate analysis, although it was not as relevant as the examination according to ASIA-ISCoS performed at admission (p = 0.005 vs p < 0.001). Mean variation of the MI was also significantly different (p < 0.001) between the three groups: 22.6 ± 21.4 for single-level edema, 16.9 ± 21.1 for multilevel edema, and 4.5 ± 8.4 for hemorrhage. Conclusion: MR injury patterns observed at the acute phase are associated with the possibility of improvement of the AIS score and MI.

ACS central science 8(1), 57 - 66 (2022). doi:10.1021/acscentsci.1c00434, Optical control has enabled functional modulation in cell culture with unparalleled spatiotemporal resolution. However, current tools for in vivo manipulation are scarce. Here, we design and implement a genuine on-off optochemical probe capable of achieving hematopoietic control in zebrafish. Our photopharmacological approach first developed conformationally strained visible light photoswitches (CS-VIPs) as inhibitors of the histone methyltransferase MLL1 (KMT2A). In blood homeostasis MLL1 plays a crucial yet controversial role. CS-VIP 8 optimally fulfils the requirements of a true bistable functional system in vivo under visible-light irradiation, and with unprecedented stability. These properties are exemplified via hematopoiesis photoinhibition with a single isomer in zebrafish. The present interdisciplinary study uncovers the mechanism of action of CS-VIPs. Upon WDR5 binding, CS-VIP 8 causes MLL1 release with concomitant allosteric rearrangements in the WDR5/RbBP5 interface. Since our tool provides on-demand reversible control without genetic intervention or continuous irradiation, it will foster hematopathology and epigenetic investigations. Furthermore, our workflow will enable exquisite photocontrol over other targets inhibited by macrocycles., Published by ACS Publ., Washington, DC

COVID-19; Heart disease; Persistent COVID 19; Malaltia cardíaca; Persistent COVID-19; Enfermedad cardíaca; Persistente Background: Heart disease is linked to worse acute outcomes after coronavirus disease 2019 (COVID-19), although long-term outcomes and prognostic factor data are lacking. We aim to characterize the outcomes and the impact of underlying heart diseases after surviving COVID-19 hospitalization. Methods: We conducted an analysis of the prospective registry HOPE-2 (Health Outcome Predictive Evaluation for COVID-19-2, NCT04778020). We selected patients discharged alive and considered the primary end-point all-cause mortality during follow-up. As secondary main end-points, we included any readmission or any post-COVID-19 symptom. Clinical features and follow-up events are compared between those with and without cardiovascular disease. Factors with p < 0.05 in the univariate analysis were entered into the multivariate analysis to determine independent prognostic factors. Results: HOPE-2 closed on 31 December 2021, with 9299 patients hospitalized with COVID-19, and 1805 died during this acute phase. Finally, 7014 patients with heart disease data were included in the present analysis, from 56 centers in 8 countries. Heart disease (+) patients were older (73 vs. 58 years old), more frequently male (63 vs. 56%), had more comorbidities than their counterparts, and suffered more frequently from post-COVID-19 complications and higher mortality (OR heart disease: 2.63, 95% CI: 1.81–3.84). Vaccination was found to be an independent protector factor (HR all-cause death: 0.09; 95% CI: 0.04–0.19). Conclusions: After surviving the acute phase, patients with underlying heart disease continue to present a more complex clinical profile and worse outcomes including increased mortality. The COVID-19 vaccine could benefit survival in patients with heart disease during follow-up. Non-conditioned grant (Fundación Interhospitalaria para la Investigación cardiovascular, FIC. Madrid, Spain). This nonprofit institution had no role in the study design; collection, analysis, or interpretation of data; in the writing of the report; nor in the decision to submit the paper for publication.

Background: Cytoreductive surgery (CRS) in combination with hyperthermic intraperitoneal chemotherapy (HIPEC) is an option in advanced peritoneal sarcomatosis. Nevertheless, CRS and HIPEC are not successful in all patients. An enhancement of HIPEC using photodynamic therapy might be beneficial. Therefore, a combination of the photosensitizer Hypericin (HYP) with HIPEC was evaluated in an animal model. Procedure: An established HIPEC animal model for rhabdomyosarcoma (NOD/LtSz-scid IL2Rγnullmice, n=80) was used. All groups received HYP (100 µg/200 µl) intraperitoneally with and without cisplatin-based (30 or 60 mg/m2) HIPEC (37 or 42 °C, for 60 min) (five groups, each n=16). Tumor dissemination was documented visually and by using HYP-based fluorescence guidance. HYP-based photodynamic therapy (PDT) of the tumor was performed. Finally, tissue samples were evaluated regarding proliferation (Ki-67) and apoptosis (TUNEL). Results: HYP uptake even in smallest tumor nodes (< 1 mm) was found. HYP-based fluorescence guidance allowed a better tumor detection in comparison to visual inspection. Immunohistochemistry revealed HYP penetration across the tumor surface. HYP-based PDT without HIPEC induced marginal apoptotic effects at the tumor surface. Combining HYP with HIPEC revealed cisplatin concentration dependent decrease in proliferation capacity and induction of apoptosis across determined cell layers of the tumor surfaces. Conclusion: HYP as fluorescent photosensitizer offers an intraoperative diagnostic advantage detecting intraperitoneal tumor dissemination. The combination of HYP and cisplatin-based HIPEC was feasible in vivo showing enhanced effects on tumor proliferation and apoptosis induction across the tumor surface. Further studies combining HYP and HIPEC will follow to establish a clinical application.

International audience; The European Federation for Medicinal chemistry and Chemical biology (EFMC) is a federation of learned societies. It groups organizations of European scientists working in a dynamic field spanning chemical biology and medicinal chemistry. New ideas, tools, and technologies emerging from a wide array of scientific disciplines continuously energize this rapidly evolving area. Medicinal chemistry is the design, synthesis, and optimization of biologically active molecules aimed at discovering new drug candidatesa mission that in many ways overlaps with the scope of chemical biology. Chemical biology is by now a mature field of science for which a more precise definition of what it englobes, in the frame of EFMC, is timely. This article discusses chemical biology as currently understood by EFMC, including all activities dealing with the design and synthesis of biologically active chemical tools and their use to probe, characterize, or influence biological systems.

We report a high-affinity photoswitchable DNA binder, which displays different nucleosome-binding capacities upon visible-light irradiation. Both photochemical and DNA-recognition properties were examined by UV-Vis, HPLC, CD spectroscopy, NMR, FID assays, EMSA and DLS. Our probe sets the basis for developing new optoepigenetic tools for conditional modulation of nucleosomal DNA accessibility.

SummaryThe ATP-dependent nucleosome remodeller Mi-2/CHD4 broadly modulates epigenetic landscapes to repress transcription and to maintain genome integrity. Here we use individual nucleotide resolution crosslinking and immunoprecipitation (iCLIP) to show that Drosophila Mi-2 associates with thousands of mRNA molecules in vivo. Biochemical data reveal that recombinant dMi-2 preferentially binds to G-rich RNA molecules using two intrinsically disordered regions of previously undefined function. Pharmacological inhibition of transcription and RNase digestion approaches establish that RNA inhibits the association of dMi-2 with chromatin. We also show that RNA inhibits dMi-2-mediated nucleosome mobilization by competing with the nucleosome substrate. Importantly, this activity is shared by CHD4, the human homolog of dMi-2, strongly suggesting that RNA-mediated regulation of remodeller activity is an evolutionary conserved mechanism. Our data support a model in which RNA serves to protect actively transcribed regions of the genome from dMi-2/CHD4- mediated establishment of repressive chromatin structures.

Despite the risks associated with the use of new forms of tobacco consumption, such as electronic cigarettes or heated tobacco products such as IQOS (I Quit Ordinary Smoking), few studies have estimated the prevalence of use at the population level. The aims of this study were to describe, in Galicia, the evolution of the prevalence of the use of electronic cigarettes and the reasons for its use in the period 2014-2018, and, the use and knowledge of IQOS in 2018.The information analyzed comes from 4 cross-sectional surveys conducted in 2014 (n=7,874), 2015 (n=7,908), 2017 (n=7,841) and 2018 (n=7,853) within the framework of the Information System on Risk Behaviors (SICRI), being the target population Galicians aged 16 and over. Estimates of prevalence of consumption, the devices knowledge and reasons for use are shown accompanied with 95% confidence intervals (95% CI), globally, by gender, age group and tobacco consumption.In the period under study, the prevalence of electronic cigarette use remained stable. In 2018 it was estimated at 0.7% (0.5-0.9). In 2017, the only year in which changes were observed, it fell to 0.3% (0.2-0.4). Prevalence of electronic cigarette use among the population aged 16 to 24 increased from 0.8% in 2014 to 2.1% in 2018. The main reason for using electronic cigarettes was to quit smoking. The prevalence of the IQOS use at the time study (2018) was 0.1% (0.01-0.15) and 4.2% (3.7-4.7) of the Galicians knew what the IQOS was.In Galicia, the prevalence of electronic cigarette and IQOS use is low, although an increase was observed among the population aged 16-24 between 2014 and 2018. Surveillance of use at the population level should not be neglected.A pesar de los riesgos asociados al uso de nuevas formas de consumo de tabaco, como los cigarrillos electrónicos o los productos de tabaco calentado como los IQOS (I Quit Ordinary Smoking), son pocos los estudios que han estimado su prevalencia de uso a nivel poblacional. Los objetivos de este trabajo fueron describir, en Galicia, la evolución de la prevalencia y las razones de uso de cigarrillos electrónicos en el periodo 2014-2018; y el uso y conocimiento del IQOS en 2018.La información analizada procede de 4 estudios transversales que se realizaron en 2014 (n=7.874), 2015 (n=7.908), 2017 (n=7.841) y 2018 (n=7.853) en el marco del Sistema de Información sobre Conductas de Riesgo (SICRI), siendo la población objetivo la población gallega de 16 años y más. Se presentan estimaciones puntuales de prevalencia de consumo y de conocimiento de los dispositivos y razones de uso acompañadas de intervalos de confianza al 95% (IC95%), en global, en función del sexo, el grupo de edad y el consumo de tabaco.En el periodo a estudio la prevalencia de uso de cigarrillos electrónicos se mantuvo estable. En 2018 se estimó en el 0,7% (0,5-0,9). En 2017, único año en el que se observaron cambios, se redujo al 0,3% (0,2-0,4). La prevalencia de uso de cigarrillos electrónicos entre la población de 16 a 24 años pasó del 0,8% en 2014 al 2,1% en 2018. El principal motivo de su uso de cigarrillos electrónicos fue dejar de fumar. La prevalencia de uso de IQOS en el momento del estudio (2018) fue del 0,1% (0,01-0,15) y el 4,2% (3,7-4,7) de los gallegos sabían lo que era el IQOS.En Galicia, la prevalencia de uso de cigarrillos electrónicos e IQOS es baja, aunque se observó un aumento entre la población de 16 a 24 años entre 2014 y 2018. No se debe descuidar la vigilancia del uso a nivel poblacional.

The ATP-dependent nucleosome remodeller Mi-2/CHD4 broadly modulates epigenetic landscapes to repress transcription and to maintain genome integrity. Here we use individual nucleotide resolution crosslinking and immunoprecipitation (iCLIP) to show that Drosophila Mi-2 associates with thousands of mRNA molecules in vivo. Biochemical data reveal that recombinant dMi-2 preferentially binds to G-rich RNA molecules using two intrinsically disordered regions of previously undefined function. Pharmacological inhibition of transcription and RNase digestion approaches establish that RNA inhibits the association of dMi-2 with chromatin. We also show that RNA inhibits dMi-2-mediated nucleosome mobilization by competing with the nucleosome substrate. Importantly, this activity is shared by CHD4, the human homolog of dMi-2, strongly suggesting that RNA-mediated regulation of remodeller activity is an evolutionary conserved mechanism. Our data support a model in which RNA serves to protect actively transcribed regions of the genome from dMi-2/CHD4mediated establishment of repressive chromatin structures.

A persisting obstacle in human immunology is that blood-derived leukocytes are notoriously difficult to manipulate at the RNA level. Therefore, our knowledge about immune-regulatory RNA-networks is largely based on tumour cell-line and rodent knockout models, which do not fully mimic human leukocyte biology. Here, we exploit straightforward cell penetrating peptide (CPP) chemistry to enable efficient loss-of-function phenotyping of regulatory RNAs in primary human blood-derived cells. The classical CPP octaarginine (R8) enabled antisense peptide-nucleic-acid (PNA) oligomer delivery into nearly 100% of human blood-derived macrophages without apparent cytotoxicity even up to micromolar concentrations. In a proof-of-principle experiment, we successfully de-repressed the global microRNA-155 regulome in primary human macrophages using a PNA-R8 oligomer, which phenocopies a CRISPR-Cas9 induced gene knockout. Interestingly, although it is often believed that fairly high concentrations (μM) are needed to achieve antisense activity, our PNA-R8 was effective at 200 nM. RNA-seq characterized microRNA-155 as a broad-acting riboregulator, feedback restraining a late myeloid differentiation-induced pro-inflammatory network, comprising MyD88-signalling and ubiquitin-proteasome components. Our results highlight the important role of the microRNA machinery in fine-control of blood-derived human phagocyte immunity and open the door for further studies on regulatory RNAs in difficult-to-transfect primary human immune cells.

The ATP-dependent nucleosome remodeler Mi-2/CHD4 broadly modulates chromatin landscapes to repress transcription and to maintain genome integrity. Here we use individual nucleotide resolution crosslinking and immunoprecipitation (iCLIP) to show that Drosophila Mi-2 associates with thousands of mRNA molecules in vivo. Biochemical data reveal that recombinant dMi-2 preferentially binds to G-rich RNA molecules using two intrinsically disordered regions of unclear function. Pharmacological inhibition of transcription and RNase digestion approaches establish that RNA inhibits the association of dMi-2 with chromatin. We also show that RNA inhibits dMi-2-mediated nucleosome mobilization by competing with the nucleosome substrate. Importantly, this activity is shared by CHD4, the human homolog of dMi-2, strongly suggesting that RNA-mediated regulation of remodeler activity is an evolutionary conserved mechanism. Our data support a model in which RNA serves to protect actively transcribed regions of the genome from dMi-2/CHD4-mediated establishment of repressive chromatin structures.

The generation of lineage-specific gene expression programmes that alter proliferation capacity, metabolic profile and cell type-specific functions during differentiation from multipotent stem cells to specialised cell types is crucial for development. During differentiation gene expression programmes are dynamically modulated by a complex interplay between sequence-specific transcription factors, associated cofactors and epigenetic regulators. Here, we study U-shaped (Ush), a multi-zinc finger protein that maintains the multipotency of stem cell-like hemocyte progenitors during Drosophila hematopoiesis. Using genomewide approaches we reveal that Ush binds to promoters and enhancers and that it controls the expression of three gene classes that encode proteins relevant to stem cell-like functions and differentiation: cell cycle regulators, key metabolic enzymes and proteins conferring specific functions of differentiated hemocytes. We employ complementary biochemical approaches to characterise the molecular mechanisms of Ush-mediated gene regulation. We uncover distinct Ush isoforms one of which binds the Nucleosome Remodeling and Deacetylation (NuRD) complex using an evolutionary conserved peptide motif. Remarkably, the Ush/NuRD complex specifically contributes to the repression of lineage-specific genes but does not impact the expression of cell cycle regulators or metabolic genes. This reveals a mechanism that enables specific and concerted modulation of functionally related portions of a wider gene expression programme. Finally, we use genetic assays to demonstrate that Ush and NuRD regulate enhancer activity during hemocyte differentiation in vivo and that both cooperate to suppress the differentiation of lamellocytes, a highly specialised blood cell type. Our findings reveal that Ush coordinates proliferation, metabolism and cell type-specific activities by isoform-specific cooperation with an epigenetic regulator., Author summary In multicellular organisms common progenitors differentiate into various kinds of specialised cells. During differentiation metabolic profiles and proliferation potentials are progressively adjusted and cell type-specific traits are established by the coordinated activation and inactivation of genes. Here we study U-shaped (Ush), a conserved gene regulator that acts during macrophage differentiation in Drosophila melanogaster. We uncover that Ush coordinates the activation and inactivation of three differentiation-related gene groups, thereby modulating lipid metabolism, promoting cell division and maintaining a progenitor state. These functions are conferred by different Ush protein isoforms and their associated co-factors. One such co-factor, the nucleosome remodeling and deacetylation complex dNuRD, contributes to progenitor state maintenance but is not required for other Ush-regulated processes. This exemplifies how a single gene regulator can simultaneously influence different aspects of cellular differentiation by employing protein isoforms and isoform-specific co-regulator interactions.

DNA-binding polyamides are synthetic oligomers of pyrrole/imidazole units with high specificity and affinity for double-stranded DNA. To increase their synthetic diversity, we report a mild methodology based on 4-methyltrityl (Mtt) solid phase peptide synthesis (SPPS), whose building blocks are more accessible than the standard Fmoc and Boc SPPS ones. We demonstrate the robustness of the approach by preparing and studying a hairpin with all precursors. Importantly, our strategy is orthogonal and compatible with sensitive molecules and could be readily automated.

We describe a cell-permeable photoswitchable probe capable of modulating epigenetic cellular states by disruption of an essential protein–protein interaction within the MLL1 methyltransferase core complex. Our azobenzene-containing peptides selectively block the WDR5-MLL1 interaction by binding to WDR5 with high affinity (Ki = 1.25 nM). We determined the co-crystal structure of this photoswitchable peptiomimetic with WDR5 to understand the interaction at the atomic level. Importantly, the photoswitchable trans and cis conformers of the probe display a clear difference in their inhibition of MLL1. We further demonstrate that the designed photo-controllable azo-peptidomimetics affect the transcription of the MLL1-target gene Deptor, which regulates hematopoiesis and leukemogenesis, and inhibit the growth of leukemia cells. This strategy demonstrates the potential of photopharmacological inhibition of methyltransferase protein–protein interactions as a novel method for external epigenetic control, providing a new toolbox for controlling epigenetic states.

Light is unsurpassed in its ability to modulate biological interactions. Since their discovery, chemists have been fascinated by photosensitive molecules capable of switching between isomeric forms, known as photoswitches. Photoswitchable peptides have been recognized for many years; however, their functional implementation in biological systems has only recently been achieved. Peptides are now acknowledged as excellent protein–protein interaction modulators and have been important in the emergence of photopharmacology. In this review, we briefly explain the different classes of photoswitches and summarize structural studies when they are incorporated into peptides. Importantly, we provide a detailed overview of the rapidly increasing number of examples, where biological modulation is driven by the structural changes. Furthermore, we discuss some of the remaining challenges faced in this field. These exciting proof-of-principle studies highlight the tremendous potential of photocontrollable peptides as optochemical tools for chemical biology and biomedicine.

We report the use of bioorthogonal reactions as an original strategy in photodynamic therapy to achieve conditional phototoxicity and specific subcellular localization simultaneously. Our novel halogenated BODIPY-tetrazine probes only become efficient photosensitizers (ΦΔ ≈0.50) through an intracellular inverse-electron-demand Diels-Alder reaction with a suitable dienophile. Ab initio computations reveal an activation-dependent change in decay channels that controls 1 O2 generation. Our bioorthogonal approach also enables spatial control. As a proof-of-concept, we demonstrate the feasibility of the selective activation of our dormant photosensitizer in cellular nuclei, causing cancer cell death upon irradiation. Thus, our dual biorthogonal, activatable photosensitizers open new venues to combat current limitations of photodynamic therapy.

Life relies on a myriad of carefully orchestrated processes, in which proteins and their direct interplay ultimately determine cellular function and disease. Modulation of this complex crosstalk has recently attracted attention, even as a novel therapeutic strategy. Herein, we describe the synthesis and characterization of two visible-light-responsive peptide backbone photoswitches based on azobenzene derivatives, to exert optical control over protein-protein interactions (PPI). The novel peptidomimetics undergo fast and reversible isomerization with low photochemical fatigue under alternatively blue-/green-light irradiation cycles. Both bind in the nanomolar range to the protein of interest. Importantly, the best peptidomimetic displays a clear difference between isomers in its protein-binding capacity and, in turn, in its potential to inhibit enzymatic activity through PPI disruption. In addition, crystal structure determination, docking and molecular dynamics calculations allow a molecular interpretation and open up new avenues in the design and synthesis of future photoswitchable PPI modulators.

Native chemical ligation (NCL) is a powerful method for the convergent synthesis of proteins and peptides. In its original format, NCL between a peptide containing a C-terminal thioester and another peptide offering an N-terminal cysteine has been used to enable protein synthesis of unprotected peptide fragments. However, the applications of NCL extend beyond the scope of protein synthesis. For instance, NCL can be put under the control of template molecules. In such a scenario, NCL enables the design of conditional reaction systems in which, peptide bond formation occurs only when a specific third party molecule is present. In this review, we will show how templates can be used to control the reactivity and chemoselectivity of NCL reactions. We highlight peptide and nucleic-acid-templated NCL reactions and discuss potential applications in nucleic acid diagnosis, origin-of-life studies and gene-expression-specific therapies. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.

We describe a RNA-programmed peptidyl transfer reaction, which triggers the formation of a cytotoxic, cell permeant 14-mer peptide–PNA conjugate from inactive fragments. Turnover in the RNA template is required to evoke the bioactivity. HeLa cells enabled the read-out of the reaction, which proceeded rapidly when it was performed on matched RNA templates.

Efficient targeting of DNA by designed molecules requires not only careful fine-tuning of their DNA-recognition properties, but also appropriate cell internalization of the compounds so that they can reach the cell nucleus in a short period of time. Previous observations in our group on the relatively high affinity displayed by conjugates between distamycin derivatives and bZIP basic regions for A-rich DNA sites, led us to investigate whether the covalent attachment of a positively charged cell-penetrating peptide to a distamycin-like tripyrrole might yield high affinity DNA binders with improved cell internalization properties. Our work has led to the discovery of synthetic tripyrrole-octa-arginine conjugates that are capable of targeting specific DNA sites that contain A-rich tracts with low nanomolar affinity; they simultaneously exhibit excellent membrane and nuclear translocation properties in living HeLa cells.