Initial Characterization of the Viridisins' Biological Properties.

Viridisin A1 and A2 were previously heterologously expressed, purified, and characterized as ribosomally produced and post-translationally modified lanthipeptides. Such lanthipeptide operons are surprisingly common in Gram-negative bacteria, although their expression seems to be predominantly cryptic under laboratory conditions. However, the bioactivity and biological role of most lanthipeptide operons originating from marine-associated Pseudomonadota, such asThalassomonas viridans XOM25T, have not been described. Therefore, marine-associated Gram-negative lanthipeptide operons represent an untapped resource for novel structures, biochemistries, and bioactivities. Here, the upscaled production of viridisin A1 and A2 was performed for (methyl)lanthionine stereochemistry characterization, antibacterial, antifungal, and larval zebrafish behavioral screening. While antimicrobial activity was not observed, the VirBC modification machinery was found to install both dl- and ll-lanthionine stereoisomers. The VdsA1 and VdsA2 peptides induced sedative and stimulatory effects in zebrafish larvae, respectively, which is a bioactivity not previously reported from lanthipeptides. When combined, VdsA1 and VdsA2 counteracted the sedative and stimulatory effects observed when used individually.

Potential of bone morphogenetic protein-7 in treatment of lupus nephritis: addressing the hurdles to implementation.

Up to 50% of systemic lupus erythematosus (SLE) patients world-wide develop lupus nephritis (LN). In low to middle income countries and in particular in sub-Saharan Africa, where SLE is prevalent with a more aggressive course, LN and end stage renal disease is a major cause of mortality. While developed countries have the funding to invest in SLE and LN research, patients of African descent are often underrepresented in clinical trials. Thus, the complex influence of ethnicity and genetic background on outcome of LN and SLE as a whole, is not fully understood. Several pathophysiological mechanisms including major role players driving LN have been identified. A large body of literature suggest that prevention of fibrosis-which contributes to chronicity of LN-may significantly improve long-term prognosis. Bone morphogenetic protein-7 (BMP-7) was first identified as a therapeutic option in this context decades ago and evidence of its benefit in various conditions, including LN, is ever-increasing. Despite these facts, BMP-7 is not being implemented as therapy in the context of renal disease. With this review, we briefly summarise current understanding of LN pathology and discuss the evidence in support of therapeutic potential of BMP-7 in this context. Lastly, we address the obstacles that need to be overcome, before BMP-7 may become available as LN treatment.

Therapeutic Benefit in Rheumatoid Cachexia Illustrated Using a Novel Primary Human Triple Cell Coculture Model.

Background: The loss of muscle mass in rheumatoid arthritis (RA), termed rheumatoid cachexia, is predicted to result from the complex interactions between different cell types involved in the maintenance of skeletal muscle mass, namely, myoblasts, fibroblasts, and macrophages. The complexity within the muscle is further highlighted by the incidence of nonresponsiveness to current RA treatment strategies. Method: This study aimed at determining differences in the cellular responses in a novel human primary cell triple coculture model exposed to serum collected from nonarthritic controls (NC), RA treatment naïve (RATN), and RA treatment-nonresponding (RATNR) patients. Bone morphogenetic protein-7 (BMP-7) was investigated as a treatment option. Results: Plasma analysis indicated that samples were indeed representative of healthy and RA patients-notably, the RATNR patients additionally exhibited dysregulated IL-6/IL-10 correlations. Coculture exposure to serum from RATNR patients demonstrated increased cellular growth (p < 0.001), while both hepatocyte growth factor (p < 0.01) and follistatin (p < 0.001) were reduced when compared to NC. Furthermore, decreased concentration of markers of extracellular matrix formation, transforming growth factor-ß (TGF-ß; p < 0.05) and fibronectin (p < 0.001), but increased collagen IV (p < 0.01) was observed following RATNR serum exposure. Under healthy conditions, BMP-7 exhibited potentially beneficial results in reducing fibrosis-generating TGF-ß (p < 0.05) and fibronectin (p < 0.05). BMP-7 further exhibited protective potential in the RA groups through reversing the aberrant tendencies observed especially in the RATNR serum-exposed group. Conclusion: Exposure of the triple coculture to RATN and RATNR serum resulted in dysregulated myoblast proliferation and growth, and ECM impairment, which was reversed by BMP-7 treatment.

Total mRNA and primary human myoblasts' in vitro cell cycle progression distinguishes between clones.

Satellite cells are generally quiescent in vivo. Once activated, progression through the cell cycle begins. Immortalised myoblasts from a single cell line are fairly homogenous in culture, but primary human myoblasts (PHMs) demonstrate heterogeneity. This phenomenon is poorly understood however may impact on PHM expansion. This study aimed to evaluate cell cycle transition from growth to synthesis phases of the cell cycle (G1 to S phase) and total mRNA relevant to this transition in PHM clones derived from 2 donor biopsies. Proportions of cells transitioning from G1 to S phase were evaluated at 2-hourly intervals for 24 h (n = 3 for each) and total mRNA quantified. Both PHM clones revealed an exponential transition from G1 to S phase over time, with a significantly slower rate for PHMs from S9.1 compared to S6.3, which had a higher proportion of PHMs in S phase for most time-points (p < 0.05). After 24 h the proportion of PHMs in S phase was ∼13% (S6.3) compared to ∼22% (S9.1). Gene transcription increased as cells progressed from G1 to S phase. Although total RNA increased with similar linearity in both clones, S6.3 PHMs had consistently (10 out of 12 time points) significantly higher concentrations. Validating the 2-hourly assessment over 24 h, a 4-hourly assessment from 8 to 32 h revealed similar differences but included the beginning of a plateau. This study demonstrates that PHMs from different donors differ in both cell cycle progression and overall transcriptome revealing new aspects in the heterogeneity of isolated satellite cells in vitro.

Advances in fluorescence microscopy can reveal important new aspects of tissue regeneration.

Advances in fluorescence microscopy can greatly facilitate research in regenerative health. Specifically, live cell imaging is a powerful tool to understand the underlying mechanisms of tissue regeneration, which is characterised by a dynamic interplay at cellular and molecular level. Recent advances in microscopy have aimed to overcome some of the most challenging limitations, such as slow acquisition speed, the resolution limit of light, low signal to noise ratio in thick samples, as well as photobleaching and phototoxicity. In applications such as lightsheet fluorescence microscopy and intra-vital multi-photon microscopy, improved deep tissue imaging have been achieved, and super-resolution technologies have shown to improve optical resolution far beyond the diffraction limit of light for better visualisation at the cellular and molecular level. By combining certain techniques, researchers can now image live samples at much higher resolution for a prolonged time. Advances in analytical technologies will enable researchers to gain an even better understanding of the processes involved to ultimately translate stem cell research into therapeutic interventions.

Unresolved intramuscular inflammation, not diminished skeletal muscle regenerative capacity, is at the root of rheumatoid cachexia: insights from a rat CIA model.

Rheumatoid arthritis targets numerous organs in patients, including the skeletal muscle, resulting in rheumatoid cachexia. In the muscle niche, satellite cells, macrophages, and myofibroblasts may be affected and the factors they release altered. This study aimed to assess these cell types, cytokines, and growth factors and their relationships to muscle fiber size and number in a rodent collagen-induced arthritis (CIA) model, in order to identify new therapeutic targets. Fiber cross-sectional area (CSA) was 57% lower in CIA than controls (p < 0.0001), thus smaller but more fibers visible per field of view. Immunostaining indicated the increased presence of satellite cells, macrophages, myofibroblasts, and myonuclei per field of view in CIA (p < 0.01), but this finding was not maintained when taking fiber number into consideration. Western blots of gastrocnemius samples indicated that tumor necrosis factor-α was significantly elevated (p < 0.01) while interleukin-10 (IL-10) was decreased (p < 0.05) in CIA. This effect was maintained (and heightened for IL-10) when expressed per fiber number. Myogenic regulatory factors (MyoD and myogenin), transforming growth factor-ß and inhibitor of differentiation were significantly elevated in CIA muscle and levels correlated significantly with CSA. Several of these factors remained elevated, but bone morphogenetic protein-7 decreased when considering fiber number per area. In conclusion, CIA-muscle demonstrated a good regenerative response. Myoblast numbers per fiber were not elevated, suggesting their activity results from the persistent inflammatory signaling which also significantly hampered maintenance of muscle fiber size. A clearer picture of signaling events at cellular level in arthritis muscle may be derived from expressing data per fiber.