NOX4 inhibition promotes the remodeling of dystrophic muscle

The muscular dystrophies (MDs) are genetic muscle diseases that result in progressive muscle degeneration followed by the fibrotic replacement of affected muscles as regenerative processes fail. Therapeutics that specifically address the fibrosis and failed regeneration associated with MDs represent a major unmet clinical need for MD patients, particularly those with advanced stage disease progression. The current study investigates targeting NAD(P)H oxidase (NOX) 4 as a potential strategy to reduce fibrosis and promote regeneration in disease-burdened muscle that models Duchenne muscular dystrophy (DMD). NOX4 is elevated in the muscles of dystrophic mice and DMD patients, localizing primarily to interstitial cells located between muscle fibers. Genetic and pharmacological targeting of NOX4 significantly reduces fibrosis in dystrophic respiratory and limb muscles. Mechanistically, NOX4 targeting decreases the number of fibrosis-depositing cells (myofibroblasts) and restores the number of muscle-specific stem cells (satellite cells) to their physiological niche, thereby, rejuvenating muscle regeneration. Furthermore, acute inhibition of NOX4 is sufficient to induce apoptotic clearing of myofibroblasts within dystrophic muscle. These data indicate that targeting NOX4 is an effective strategy to promote the beneficial remodeling of disease-burdened muscle representative of DMD and, potentially, other MDs and muscle pathologies.

Macrophage-Derived Exosomes Promote Bone Mesenchymal Stem Cells Towards Osteoblastic Fate Through microRNA-21a-5p

The effective healing of a bone defect is dependent on the careful coordination of inflammatory and bone-forming cells. In the current work, pro-inflammatory M1 and anti-inflammatory M2 macrophages were co-cultured with primary murine bone mesenchymal stem cells (BMSCs), in vitro, to establish the cross-talk among polarized macrophages and BMSCs, and as well as their effects on osteogenesis. Meanwhile, macrophages influence the osteogenesis of BMSCs through paracrine forms such as exosomes. We focused on whether exosomes of macrophages promote osteogenic differentiation. The results indicated that M1 and M2 polarized macrophage exosomes all can promote osteogenesis of BMSCs. Especially, M1 macrophage-derived exosomes promote osteogenesis of BMSCs through microRNA-21a-5p at the early stage of inflammation. This research helps to develop an understanding of the intricate interactions among BMSCs and macrophages, which can help to improve the process of bone healing as well as additional regenerative processes by local sustained release of exosomes.

Development of Wound Dressing for Regenerative Medicine

The understanding of the pathophysiological mechanisms of the wound process deepened with the development of science. The technological base that was creating has enabled to serve the clinical needs of tissue repair. These factors, combined with the growing need for healing of infected and chronic wounds, have led to the expansion of the market for wound dressings materials supplies. In this connection, there is a need to generalize and update information about new types of dressings. This review provides an up-to-date understanding of the wound process: cellular and signaling mechanisms of repair, characteristics of the optimal microclimate of the wound bed, morphofunctional re-arrangements of tissues during the healing process. Based on these data, the requirements for the modern wound dressings are formulated. Existing wound dressings have been classified as interacting with body tissue. The bio-functional characteristics of the synthetic and natural polymers used in the dressing are described, including their effect on regenerative processes. A classification of the active medicinal ingredients used in the manufacture of dressings is given, the characteristics of their use on the background of the pathological wound process are considered.

Rehabilitation aspects of nutritional correction after extensive combined sequity resection

The purpose is the tactics of nutritional rehabilitation after extensive intestinal resection. The metabolic characteristics of the short intestine syndrome and the consequences of combined fine-binding resections, as well as the adaptive and regenerative capabilities of the bowel, are presented. The optimal scheme of nutritional correction for the consequences of combined bowel resections is presented.Conclusion. To stimulate adaptive-regenerative processes in the intestine, it is advisable to use teduglutide (analogue of GLP-2); if ineffective, surgical rehabilitation can be recommended.

Regeneration in Echinoderms: Molecular Advancements

Which genes and gene signaling pathways mediate regenerative processes? In recent years, multiple studies, using a variety of animal models, have aimed to answer this question. Some answers have been obtained from transcriptomic and genomic studies where possible gene and gene pathway candidates thought to be involved in tissue and organ regeneration have been identified. Several of these studies have been done in echinoderms, an animal group that forms part of the deuterostomes along with vertebrates. Echinoderms, with their outstanding regenerative abilities, can provide important insights into the molecular basis of regeneration. Here we review the available data to determine the genes and signaling pathways that have been proposed to be involved in regenerative processes. Our analyses provide a curated list of genes and gene signaling pathways and match them with the different cellular processes of the regenerative response. In this way, the molecular basis of echinoderm regenerative potential is revealed, and is available for comparisons with other animal taxa.

Functional Roles for CD26/DPP4 in Mediating Inflammatory Responses of Pulmonary Vascular Endothelial Cells

Excessive inflammation in the lung is a primary cause of acute respiratory distress syndrome (ARDS). CD26/dipeptidyl peptidase-4 (DPP4) is a transmembrane protein that is expressed in various cell types and exerts multiple pleiotropic effects. We recently reported that pharmacological CD26/DPP4 inhibition ameliorated lipopolysaccharide (LPS)-induced lung injury in mice and exerted anti-inflammatory effects on human lung microvascular endothelial cells (HLMVECs), in vitro. However, the mechanistic roles of CD26/DPP4 in lung injury and its effects on HLMVECs remain unclear. In this study, transcriptome analysis, followed by various confirmation experiments using siRNA in cultured HLMVECs, are performed to evaluate the role of CD26/DPP4 in response to the pro-inflammatory involved in inflammation, barrier function, and regenerative processes in HLMVECs after pro-inflammatory stimulation. These are all functions that are closely related to the pathophysiology and repair process of lung injury. Confirmatory experiments using flow cytometry; enzyme-linked immunosorbent assay; quantitative polymerase chain reaction; dextran permeability assay; WST-8 assay; wound healing assay; and tube formation assay, reveal that the reduction of CD26/DPP4 via siRNA is associated with altered parameters of inflammation, barrier function, and the regenerative processes in HLMVECs. Thus, CD26/DPP4 can play a pathological role in mediating injury in pulmonary endothelial cells. CD26/DPP4 inhibition can be a new therapeutic strategy for inflammatory lung diseases, involving pulmonary vascular damage.

SR Ca2+ handling in unbranched, immediately post-necrotic fast-twitch mdx fibres is similar to wt littermates

There is a lack of consensus in the literature regarding the effects of dystrophin deficiency on the Ca2+ handling properties of the sarcoplasmic reticulum (SR) in mdx mice, an animal model of Duchenne muscular dystrophy. One possible reason for this is that only a few studies control for the presence of branched fibres. Fibre branching, a consequence of degenerative-regenerative processes such as muscular dystrophy, has in itself a significant influence on the function of the SR. In our present study we attempt to detect early effects of dystrophin deficiency on SR Ca2+ handling by using unbranched fibres from the immediate post-necrotic stage in mdx mice (just regenerated following massive necrosis). Using kinetically-corrected Fura-2 fluorescence signals measured during twitch and tetanus, we analysed the amplitude, rise time and decay time of Δ[Ca2+]i in unfatigued and fatigued fibres. Decay was also resolved into SR pump and SR leak components. Fibres from mdx mice were similar in all respects to fibres from wt littermates apart from: (i) a longer rise time and slower rate of rise of [Ca2+]i during a tetanus; and (ii) a mitigation of the fall in Δ[Ca2+]i amplitude during the course of fatigue. Our findings suggest that the early effects of a loss of dystrophin on SR Ca2+ handling are only slight, and differ from the widely held view that there is significant Ca2+ pathology in mdx mice. It may be that Ca2+pathology is magnified by progressive branching and degeneration.

SKIN CONDITION IN EXPERIMENTAL INFECTION OF SHEEP WITH CONTAGIOUS DERMATITIS

As a result of the study, it was found that with contagious pustular dermatitis, the damage affects the epidermis and dermis of the skin. The most severe damage is recorded in the epidermis on day 9, fragments of organelles and viroplast clusters are observed in the cytoplasm. On the 22nd day, regenerative and regenerative processes prevail in the epidermis and dermis, in the form of proliferation, cell differentiation and organization of intercellular substance.

Directed Evolution and Discovery of Nitroreductase Enzymes for Targeted Cell Ablation

<p>Nitroreductase enzymes are a superfamily of bacterial flavoproteins that can catalyze the reduction of aromatic nitro groups. The reduction of an aromatic nitro group, a highly electronegative functionality, causes a large electronic shift that can profoundly affect the activity of other substituents on the aromatic ring. For example, upon nitroreduction, initially non-toxic compounds known as prodrugs can be converted into a cytotoxic form. The ability of nitroreductases to alter the activity of compounds has lead to their development as tools for multiple biotechnological applications. Of particular note is the use of nitroreductase enzymes in combination with a nitroaromatic prodrug to study the role of specific cell populations in zebrafish (Danio rerio). Zebrafish are used as model organisms to study processes such as embryonic development and tissue regeneration. By expressing a nitroreductase enzyme in a specific tissue of a zebrafish, it is possible to selectively ablate that tissue upon administration of a prodrug. The subsequent phenotypic change induced by the ablation can provide information on the physiological role of the ablated tissue, or of the regenerative processes that can be recruited to repair the damage. The goal of this thesis was to engineer or discover new nitroreductase enzymes that could expand the capabilities of cell ablation studies in zebrafish. In particular, this work sought to develop a system that would enable the dual, or multiplexed, ablation of two tissues independently within the same organism. Control over the ablation of two distinct tissues could be useful for studying tissue interactions during developmental or regenerative processes. For this to be achievable, two different nitroreductase enzymes, each possessing distinct and non-overlapping prodrug selectivities would be required. Previous studies in the Ackerley lab had identified NfsA from Escherichia coli (NfsA_Ec) and NfsA from Pseudomonas putida (NfsA_Pp) as nitroreductase enzymes that were slightly more selective for the prodrug tinidazole compared than metronidazole. In contrast the NfsB nitroreductase from Vibrio vulnificus (NfsB_Vv) was substantially more selective for metronidazole than tinidazole. To further improve the tinidazole selectivity of the NfsA enzymes, directed evolution was employed as a tool to further enhance the substrate selectivity of each enzyme. The primary outcome of this work was the evolution of an NfsA_Ec mutant that was 12 fold more selective for tinidazole over metronidazole than wild type NfsA_Ec. In addition to engineering new enzymes for cell ablation experiments, this work also sought to discover new nitroreductase enzymes from unculturable bacteria, a previously unplumbed source. The genes and gene products of unculturable bacteria can be identified and studied by expressing fragments of their DNA in a readily culturable host such as E. coli. A variety of different screening methodologies were tested for identifying nitroreductase enzymes from eDNA inserts. The compound 4-nitroimidazole was found to be capable of detecting nitroreductase expression at the level of a single colony. While no novel nitroreductase enzymes were discovered in the scope of this work, the preliminary results are encouraging that a screening strategy centred on 4-nitroimidazole in particular could successfully do so in the near future.</p>