Decellularized Fetal Matrix Suppresses Fibrotic Gene Expression and Promotes Myogenesis in a Rat Model of Volumetric Muscle Loss.

BACKGROUND: Traumatic muscle loss often results in poor functional restoration. Skeletal muscle injuries cannot be repaired without substantial fibrosis and loss of muscle function. Given its regenerative properties, the authors evaluated outcomes of fetal tissue-derived decellularized matrix for skeletal muscle regeneration. The authors hypothesized that fetal matrix would lead to enhanced myogenesis and suppress inflammation and fibrosis. METHODS: Composite tissue composed of dermis, subcutaneous tissue, and panniculus carnosus was harvested from the trunk of New Zealand White rabbit fetuses on gestational day 24 and from Sprague-Dawley rats on gestational day 18 and neonatal day 3, and decellularized using a sodium dodecyl sulfate-based negative-pressure protocol. Six, 10-mm-diameter, full-thickness rat latissimus dorsi wounds were created for each treatment, matrix was implanted (excluding the defect groups), and the wounds were allowed to heal for 60 days. Analyses were performed to characterize myogenesis, neovascularization, inflammation, and fibrosis at harvest. RESULTS: Significant myocyte ingrowth was visualized in both allogeneic and xenogeneic fetal matrix groups compared to neonatal and defect groups based on myosin heavy chain immunofluorescence staining. Microvascular networks were appreciated within all implanted matrices. At day 60, expression of Ccn2, Col1a1, and Ptgs2 were decreased in fetal matrix groups compared to defect. Neonatal matrix-implanted wounds failed to show decreased expression of Col1a1 or Ptgs2, and demonstrated increased expression of Tnf, but also demonstrated a significant reduction in Ccn2 expression. CONCLUSIONS: Initial studies of fetal matrices demonstrate promise for muscle regeneration in a rat latissimus dorsi model. Further research is necessary to evaluate fetal matrix for future translational use and better understand its effects.

Artesunate inhibits myofibroblast formation via induction of apoptosis and antagonism of pro-fibrotic gene expression in human dermal fibroblasts.

The anti-malaria drug artesunate and other chemical analogs of artemisinin have demonstrated cytostatic and cytotoxic effects in bacterial and cancer cells. Artemisinin-derived compounds have also been demonstrated to attenuate fibrosis in preclinical animal models, but the mechanisms by which this inhibition occurs are not well-understood. We investigated the effects of artesunate on the emergence of the myofibroblast, which is causally implicated in pro-fibrotic pathologies. CRL-2097 human dermal fibroblasts were analyzed for protein and transcript expression after treatment with artesunate to analyze fibroblast activation. Proliferation and apoptosis were also evaluated following treatment with artesunate in this cell line. Treatment of human dermal fibroblasts with artesunate antagonized fibroblast activation and pro-fibrotic extracellular matrix (ECM) deposition, both at basal culture conditions and when cultured in the presence of exogenous transforming growth factor-ß1 (TGF-ß1), a major pro-fibrotic cytokine. Artesunate-treated fibroblasts also demonstrated decreased proliferation and increased apoptosis. Transcript analysis by quantitative real-time polymerase chain reaction demonstrated that artesunate downregulated expression of pro-fibrotic genes including canonical myofibroblast markers, ECM genes, and several TGF-ß receptors and ligands, and upregulated expression of cell cycle inhibitors and matrix-metalloproteinases. Together, these data demonstrate that artesunate antagonizes fibroblast activation and decreases expression of pro-fibrotic genes, while also promoting myofibroblast apoptosis, suggesting that these mechanisms may be responsible in part for the anti-fibrotic effects of artesunate described previously.

PRMT8 demonstrates variant-specific expression in cancer cells and correlates with patient survival in breast, ovarian and gastric cancer.

Recent emphasis has been placed on the role of epigenetic regulators and epigenetic marks as biomarkers for cancer diagnosis and prognosis, and as therapeutic targets for treatment. One such class of regulators is the protein arginine methyltransferase (PRMT) family. The present study examined available curated data regarding the expression and alteration of one of the least studied PRMT family members, PRMT8, in various types of cancer and cancer cell lines. Publicly available cancer data on PRMT8 expression were examined using the Human Protein Atlas and the Kaplan-Meier Plotter, and reverse transcription-polymerase chain reaction was used to screen a selection of human cell lines for variant-specific PRMT8 expression. High levels of PRMT8 expression in breast, ovarian and cervical cancer was observed. Additionally, in patients with breast and ovarian cancer, high PRMT8 expression was correlated with increased patient survival, whereas in gastric cancer, high PRMT8 expression was correlated with decreased patient survival. The present study also investigated the expression of PRMT8 variant 2, a novel transcript variant recently identified in our laboratory, in various cancer cell lines. Variant-specific expression of PRMT8 in numerous distinct cancer cell lines derived from different tissues, including the expression of the novel PRMT8 variant 2 in U87MG glioblastoma cells was demonstrated. The present study proposes the possibility of PRMT8 as a cancer biomarker, based on the high level of PRMT8 expression in various types of cancer, particularly in tissues that would not normally be expected to express PRMT8, and on the correlation of PRMT8 and patient lifespan in several cancer types. Variant-specific expression of PRMT8 in diverse cancer cell lines suggests the possibility of alternate PRMT8 isoforms to have diverse effects on cancer cell phenotypes.