Modulation of functional pendant chains within poly(ethylene glycol) hydrogels for refined control of protein release

Hydrogels are highly attractive delivery vehicles for therapeutic proteins. Their innate biocompatibility, hydrophilicity and aqueous permeability allow stable encapsulation and release of proteins. The release rates also can be controlled simply by altering the crosslinking density of the polymeric network. However, the crosslinking density also influences the mechanical properties of hydrogels, generally opposite to the permeability. In addition, the release of larger proteins may be hindered below critically diminished porosity determined by the crosslinking density. Herein, the physical properties of the hydrogels are tuned by presenting functional pendant chains, independent of crosslinking density. Heterobifunctional poly(ethylene glycol) monomethacrylate (PEGMA) with various end functional groups is synthesized and copolymerized with PEG dimethacrylate (PEGDA) to engineer PEG hydrogels with pendant PEG chains. The pendant chains of the PEG hydrogels consisting of sulfonate, trimethylammonium chloride, and phenyl groups are utilized to provide negative charge, positive charge and hydrophobicity, respectively, to the hydrogels. The release rates of proteins with different isoelectric points are controlled in a wide range by the type and the density of functional pendant chains via electrostatic and hydrophobic interactions

Experimental models of dermatological diseases

This review presents analysis of experimental models of atopic dermatitis, psoriasis, skin symptoms of autoimmune systemic connective tissue diseases, and blistering skin diseases. Presented in the review are experimental models of atopic dermatitis which reproduce various stages and types of disease that allows the investigation of disease pathogenesis. Atopic dermatitis can develop spontaneously in Nc/Nga mice. There are atopic dermatitis models initiated by monoclonal IgE injection or epicutant sensitization under dermal barrier disfunction imitation. Genetically modified atopic dermatitis models - transgenic and knockout mice – are convenient for investigation of disease stages, cytokines, antigen-presenting cells and T-cells influence. We show that the psoriasis models created by genetic engineering methods are the most convenient for investigation of the role of particular cell types and specific factors in the disease development. Up-regulation of adhesion molecules, cytokines, transcription factors, inflammation mediators in both keratinocytes and immune cells of transgenic mice reveals their influence on psoriasis pathogenesis. There are descriptions of skin symptom models of autoimmune systemic connective tissue diseases and blistering skin disease models with and without genetic modifications. Each model demonstrates some peculiarities of pathogenesis and disease symptoms, whereas combined use of the models will allow to study the mechanisms of development of atopic dermatitis, psoriasis, blistering skin diseases and skin lesions under autoimmune systemic connective tissue diseases, that will contribute to the development of modern effective methods of treatment

\u3ci\u3eDrosophila\u3c/i\u3e Muller F Elements Maintain a Distinct Set of Genomic Properties Over 40 Million Years of Evolution

The Muller F element (4.2 Mb, ~80 protein-coding genes) is an unusual autosome of Drosophila melanogaster; it is mostly heterochromatic with a low recombination rate. To investigate how these properties impact the evolution of repeats and genes, we manually improved the sequence and annotated the genes on the D. erecta, D. mojavensis, and D. grimshawi F elements and euchromatic domains from the Muller D element. We find that F elements have greater transposon density (25–50%) than euchromatic reference regions (3–11%). Among the F elements, D. grimshawi has the lowest transposon density (particularly DINE-1: 2% vs. 11–27%). F element genes have larger coding spans, more coding exons, larger introns, and lower codon bias. Comparison of the Effective Number of Codons with the Codon Adaptation Index shows that, in contrast to the other species, codon bias in D. grimshawi F element genes can be attributed primarily to selection instead of mutational biases, suggesting that density and types of transposons affect the degree of local heterochromatin formation. F element genes have lower estimated DNA melting temperatures than D element genes, potentially facilitating transcription through heterochromatin. Most F element genes (~90%) have remained on that element, but the F element has smaller syntenic blocks than genome averages (3.4–3.6 vs. 8.4–8.8 genes per block), indicating greater rates of inversion despite lower rates of recombination. Overall, the F element has maintained characteristics that are distinct from other autosomes in the Drosophila lineage, illuminating the constraints imposed by a heterochromatic milieu