Diclofenac prodrugs nanoparticles: An alternative and efficient treatment for rheumatoid arthritis?

We have synthesized new lipidic prodrugs of diclofenac by grafting aliphatic chains (C10, C12, C16 and C18) to diclofenac through an ester bond. Their molecular formulas were confirmed through HR-MS and the formation of ester bond by FTIR and NMR spectroscopy. Nanoparticles of the different prodrugs were successfully formulated using emulsion evaporation method and DSPE-PEG2000 as the only excipient. All nanoparticles were spherical and had a size between 110 and 150 nm, PdI ≤ 0.2 and negative Zeta potential values from -30 to -50 mV. In addition, they were stable upon storage at 4 °C up to 30-35 days. The encapsulation efficiency of the prodrug was above 90 % independently of the aliphatic chain length grafted. Nanoparticles did not induce any toxicity on LPS-activated THP-1 cells up to a concentration of 100 µg/mL (equivalent diclofenac) whereas diclofenac sodium salt IC50 was around 20 µg/mL. Following incubation of nanoparticles with LPS-activated THP-1 cells, a dose dependent inhibition of TNF-α was observed comparable to standard diclofenac sodium. Based on in vitro studies representative nanoparticles, Prodrug 3 NPs (C16 aliphatic chain) were selected for further in vitro and in vivo studies. Upon incubation in murine plasma, Prodrug 3 NPs underwent an enzymatic cleavage and almost 70 % of diclofenac was released from nanoparticles in 8 h. In vivo studies on a collagen induced arthritis murine model showed contrasted results: on one hand Prodrug 3 NPs led to a significant decrease of arthritis score and of paw volume compared to PBS after the second injection, on the other hand the third injection induced an important hepatic toxicity with the death of half of the mice from the NP group. To promote the reduction of inflammation while avoiding hepatic toxicity using NPs would require to precisely study the No Observable Adverse Effect Level and the schedule of administration in the future.

Short tandem repeats are important contributors to silencer elements in T cells.

The action of cis-regulatory elements with either activation or repression functions underpins the precise regulation of gene expression during normal development and cell differentiation. Gene activation by the combined activities of promoters and distal enhancers has been extensively studied in normal and pathological contexts. In sharp contrast, gene repression by cis-acting silencers, defined as genetic elements that negatively regulate gene transcription in a position-independent fashion, is less well understood. Here, we repurpose the STARR-seq approach as a novel high-throughput reporter strategy to quantitatively assess silencer activity in mammals. We assessed silencer activity from DNase hypersensitive I sites in a mouse T cell line. Identified silencers were associated with either repressive or active chromatin marks and enriched for binding motifs of known transcriptional repressors. CRISPR-mediated genomic deletions validated the repressive function of distinct silencers involved in the repression of non-T cell genes and genes regulated during T cell differentiation. Finally, we unravel an association of silencer activity with short tandem repeats, highlighting the role of repetitive elements in silencer activity. Our results provide a general strategy for genome-wide identification and characterization of silencer elements.

Current pandemic COVID-19 vaccine strategies and development: a comprehensive review

The coronavirus disease-19 pandemic with the characteristics of asymptomatic condition, long incubation period and poor treatment has influenced the entire globe. Coronaviruses are important emergent pathogens, specifically, the recently emerged sever acute respiratory syndrome coronavirus 2, the causative virus of the current COVID-19 pandemic. To mitigate the virus and curtail the infection risk, vaccines are the most hopeful solution. The protein structure and genome sequence of SARS-CoV-2 were processed and provided in record time; providing feasibility to the development of COVID-19 vaccines. In an unprecedented scientific and technological effort, vaccines against SARS-CoV-2 have been developed in less than one year. This review addresses the approaches adopted for SARS-CoV-2 vaccine development and the effectiveness of the currently approved vaccines(AU)

La pandemia de COVID-19, con sus características de condición asintomática, largo periodo de incubación y escaso tratamiento, ha tenido un impacto global. Los coronavirus son importantes patógenos emergentes, específicamente, el coronavirus del síndrome respiratorio agudo severo 2 descubierto recientemente, virus causal de la actual pandemia de COVID-19. Para mitigar el virus y reducir el riesgo de infección, las vacunas son la solución más esperanzadora. La estructura de la proteína y la secuencia del genoma del SARS-CoV-2 se procesaron y proporcionaron en un tiempo récord, lo que ha permitido el desarrollo de las vacunas contra el COVID-19. En un esfuerzo científico y tecnológico sin precedentes, se han desarrollado vacunas contra el SARS-CoV-2 en menos de un año. Esta revisión aborda los enfoques adoptados para el desarrollo de la vacuna contra el SARS-CoV-2 y la eficacia de las vacunas actualmente aprobadas(AU)

Epromoters function as a hub to recruit key transcription factors required for the inflammatory response.

Gene expression is controlled by the involvement of gene-proximal (promoters) and distal (enhancers) regulatory elements. Our previous results demonstrated that a subset of gene promoters, termed Epromoters, work as bona fide enhancers and regulate distal gene expression. Here, we hypothesized that Epromoters play a key role in the coordination of rapid gene induction during the inflammatory response. Using a high-throughput reporter assay we explored the function of Epromoters in response to type I interferon. We find that clusters of IFNa-induced genes are frequently associated with Epromoters and that these regulatory elements preferentially recruit the STAT1/2 and IRF transcription factors and distally regulate the activation of interferon-response genes. Consistently, we identified and validated the involvement of Epromoter-containing clusters in the regulation of LPS-stimulated macrophages. Our findings suggest that Epromoters function as a local hub recruiting the key TFs required for coordinated regulation of gene clusters during the inflammatory response.

Integration of high-throughput reporter assays identify a critical enhancer of the Ikzf1 gene.

The Ikzf1 locus encodes the lymphoid specific transcription factor Ikaros, which plays an essential role in both T and B cell differentiation, while deregulation or mutation of IKZF1/Ikzf1 is involved in leukemia. Tissue-specific and cell identity genes are usually associated with clusters of enhancers, also called super-enhancers, which are believed to ensure proper regulation of gene expression throughout cell development and differentiation. Several potential regulatory regions have been identified in close proximity of Ikzf1, however, the full extent of the regulatory landscape of the Ikzf1 locus is not yet established. In this study, we combined epigenomics and transcription factor binding along with high-throughput enhancer assay and 4C-seq to prioritize an enhancer element located 120 kb upstream of the Ikzf1 gene. We found that deletion of the E120 enhancer resulted in a significant reduction of Ikzf1 mRNA. However, the epigenetic landscape and 3D topology of the locus were only slightly affected, highlighting the complexity of the regulatory landscape regulating the Ikzf1 locus.