Emilin2 marks the target region for mesenchymal cell accumulation in bone regeneration.

BACKGROUND: Regeneration of injured tissue is dependent on stem/progenitor cells, which can undergo proliferation and maturation processes to replace the lost cells and extracellular matrix (ECM). Bone has a higher regenerative capacity than other tissues, with abundant mesenchymal progenitor cells in the bone marrow, periosteum, and surrounding muscle. However, the treatment of bone fractures is not always successful; a marked number of clinical case reports have described nonunion or delayed healing for various reasons. Supplementation of exogenous stem cells by stem cell therapy is anticipated to improve treatment outcomes; however, there are several drawbacks including the need for special devices for the expansion of stem cells outside the body, low rate of cell viability in the body after transplantation, and oncological complications. The use of endogenous stem/progenitor cells, instead of exogenous cells, would be a possible solution, but it is unclear how these cells migrate towards the injury site. METHODS: The chemoattractant capacity of the elastin microfibril interface located protein 2 (Emilin2), generated by macrophages, was identified by the migration assay and LC-MS/MS. The functions of Emilin2 in bone regeneration were further studied using Emilin2-/- mice. RESULTS: The results show that in response to bone injury, there was an increase in Emilin2, an ECM protein. Produced by macrophages, Emilin2 exhibited chemoattractant properties towards mesenchymal cells. Emilin2-/- mice underwent delayed bone regeneration, with a decrease in mesenchymal cells after injury. Local administration of recombinant Emilin2 protein enhanced bone regeneration. CONCLUSION: Emilin2 plays a crucial role in bone regeneration by increasing mesenchymal cells. Therefore, Emilin2 can be used for the treatment of bone fracture by recruiting endogenous progenitor cells.

DOK7 Gene Therapy Enhances Neuromuscular Junction Innervation and Motor Function in Aged Mice.

Muscle denervation at the neuromuscular junction (NMJ), the essential synapse between motor neuron and skeletal muscle, is associated with age-related motor impairment. Therefore, improving muscle innervation at aged NMJs may be an effective therapeutic strategy for treating the impairment. We previously demonstrated that the muscle protein Dok-7 plays an essential role in NMJ formation, and, indeed, its forced expression in muscle enlarges NMJs. Moreover, therapeutic administration of an adeno-associated virus vector encoding human Dok-7 (DOK7 gene therapy) suppressed muscle denervation and enhanced motor activity in a mouse model of amyotrophic lateral sclerosis (ALS). Here, we show that DOK7 gene therapy significantly enhances motor function and muscle strength together with NMJ innervation in aged mice. Furthermore, the treated mice showed greatly increased compound muscle action potential (CMAP) amplitudes compared with the controls, suggesting enhanced neuromuscular transmission. Thus, therapies aimed at enhancing NMJ innervation have potential for treating age-related motor impairment.

Pathogenic Epigenetic Consequences of Genetic Alterations in IDH-Wild-Type Diffuse Astrocytic Gliomas.

Gliomas are classified by combining histopathologic and molecular features, including isocitrate dehydrogenase (IDH) status. Although IDH-wild-type diffuse astrocytic glioma (DAG) shows a more aggressive phenotype than IDH-mutant type, lack of knowledge regarding relevant molecular drivers for this type of tumor has hindered the development of therapeutic agents. Here, we examined human IDH-wild-type DAGs and a glioma mouse model with a mosaic analysis with double markers (MADM) system, which concurrently lacks p53 and NF1 and spontaneously develops tumors highly comparable with human IDH-wild-type DAG without characteristic molecular features of glioblastoma (DAG-nonMF). During tumor formation, enhancer of zeste homolog (EZH2) and the other polycomb repressive complex 2 (PRC2) components were upregulated even at an early stage of tumorigenesis, together with an increased number of genes with H3K27me3 or H3K27me3 and H3K4me3 bivalent modifications. Among the epigenetically dysregulated genes, frizzled-8 (Fzd8), which is known to be a cancer- and stem cell reprogramming-related gene, was gradually silenced during tumorigenesis. Genetic and pharmacologic inhibition of EZH2 in MADM mice showed reactivation of aberrant H3K27me3 target genes, including Fzd8, together with significant reduction of tumor size. Our study clarifies a pathogenic molecular pathway of IDH-wild-type DAG-nonMF that depends on EZH2 activity and provides a strong rationale for targeting EZH2 as a promising therapeutic approach for this type of glioma. SIGNIFICANCE: EZH2 is involved in the generation of IDH-wild-type diffuse astrocytic gliomas and is a potential therapeutic target for this type of glioma. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/79/19/4814/F1.large.jpg.

Generation of a transgenic mouse line for conditional expression of human IL-6.

IL-6 is a cytokine that is involved in various physiological and pathological conditions, and approaches using gain-of-function transgenic animals have contributed in elucidating IL-6 function. However, studies of the multiple functions of IL-6 in vivo are very time consuming because they require the generation of transgenic mice that harbor the gene encoding IL-6 under the control of specific promoters to mimic different pathologies. Here, we report the establishment of a conditional human IL-6 transgenic mouse, LGL-IL6, which conditionally expresses human IL-6 by taking advantage of the well-characterized Cre recombinase drivers.