Objective-Myocardin is a cardiac-and smooth muscle-specific transcription co-factor that potently activates the expression of downstream target genes. Previously, we demonstrated that overexpression of myocardin inhibited the proliferation of smooth muscle cells (SMCs). Recently, myocardin was reported to induce the expression of microRNA-1 (miR-1) in cardiomyocytes. In this study, we investigated whether myocardin induces miR-1 expression to mediate its inhibitory effects on SMC proliferation. Methods and Results-Using tetracycline-regulated expression (T-REx) inducible system expressing myocardin in human vascular SMCs, we found that overexpression of myocardin resulted in significant induction of miR-1 expression and inhibition of SMC proliferation, which was reversed by miR-1 inhibitors. Consistently, introduction of miR-1 into SMCs inhibited their proliferation. We isolated spindle-shaped and epithelioid human SMCs and demonstrated that spindle-shaped SMCs were more differentiated and less proliferative. Correspondingly, spindle-shaped SMCs had significantly higher expression levels of both myocardin and miR-1 than epithelioid SMCs. We identified Pim-1, a serine/threonine kinase, as a target gene for miR-1 in SMCs. Western blot and luciferase reporter assays further confirmed that miR-1 targeted Pim-1 directly. Furthermore, neointimal lesions of mouse carotid arteries displayed downregulation of myocardin and miR-1 with upregulation of Pim-1. Conclusion-Our data demonstrate that miR-1 participates in myocardin-dependent of SMC proliferation inhibition.(Arterioscler Thromb Vasc Biol. 2011;31:368-375.)

Migration of immature neurons is essential for forming the cortical layers and nuclei. Impairment of migration results in aberrant neuronal cytoarchitecture, which leads to various neurological disorders. Neurons alter the mode, tempo and rate of migration when they translocate through different cortical layers, but little is known about the mechanisms underlying this process. Here we show that endogenous pituitary adenylate cyclase-activating polypeptide (PACAP) has short-term and cortical-layer-specific effects on granule cell migration in the early postnatal mouse cerebellum. Application of exogenous PACAP significantly slowed the migration of isolated granule cells and shortened the leading process in the microexplant cultures of the postnatal day (P)0-3 cerebella. Interestingly, in the cerebellar slices of P10 mice, application of exogenous PACAP significantly inhibited granule cell migration in the external granular layer (EGL) and molecular layer (ML), but failed to alter the movement in the Purkinje cell layer (PCL) and internal granular layer (IGL). In contrast, application of PACAP antagonist accelerated granule cell migration in the PCL, but did not change the movement in the EGL, ML and IGL. Inhibition of the cAMP signaling and the activity of phospholipase C significantly reduced the effects of exogenous PACAP on granule cell migration. The PACAP action on granule cell migration was transient, and lasted for approximately 2 h. The duration of PACAP action on granule cell migration was determined by the desensitization of its receptors and prolonged by inhibiting the protein kinase C. Endogenous PACAP was present sporadically in the bottom of the ML, intensively in the PCL, and throughout the IGL. Collectively, these results indicated that PACAP acts on granule cell migration as "a brake (stop signal) for cell movement." Furthermore, these results suggest that endogenous PACAP slows granule cell migration when the cells enter the PACAP-rich PCL, and 2 h later the desensitization of PACAP receptors allows the cells to accelerate the rate of migration and to actively move within the PACAP-rich IGL. Therefore, endogenous PACAP may provide a cue that regulates granule cell migration in a cerebellar cortical-layer-specific manner.

Stachybotrys (asexual Hypocreales) has a worldwide distribution. This genus inhabits substrates rich in cellulose and is closely related to Memnoniella. Classification of species has previously been based on morphology, with conidial characters being considered as important. This study reevaluates Stachybotrys and Memnoniella, which is shown to include at least seven species-groups; while Memnoniella is a synonym of Stachybotrys. The sexual genera Ornatispora and Melanopsamma are also synonyms of Stachybotrys. With the exception of Stachybotrys subsimplex, species formed a wellsupported monophyletic group in LSU data analysis belonging to Stachybotriaceae. Seventy-four accepted Stachybotrys species are discussed, while eight species are considered to belong to other genera or are doubtful in this paper and a key to these species provided. Twelve new combinations and 1 nomina nova is proposed. The status of Stachybotrys species on health, as human or animal pathogens, in indoor environments, and use as biocontrol agents and compound discovery are also discussed.

Myocardin, a cofactor of serum response factor (SRF), specifically induces the expression of contractile proteins to promote differentiation and contractile phenotype of smooth muscle cells (SMCs). SRF directly induces the transcription of microRNA-1 (miR-1) in cardiac and skeletal muscle precursor cells and miR-1 promotes the skeletal muscle differentiation and modulates cardiac hypertrophy. We aimed to examine whether miR-1 plays a role in the regulation of smooth muscle contractility. We found that miR-1 expression was induced by myocardin overexpression in human aortic SMCs. In a collagen lattice contraction assay using SMCs harboring a doxycycline-inducible expression system for myocardin, we found that myocardin expression increased the contractility of SMCs, which was significantly inhibited by exogenous miR-1. Our further studies revealed that exogenous miR-1, which did not affect myocardin or SRF expression, suppressed the expression of contractile proteins, such as alpha-SMA and SM22, and impaired the actin cytoskeletal organization. Taken together, our results have revealed that myocardin induces miR-1 expression, which represses the expression of contractile proteins and thereby inhibits the contractility of SMCs. Therefore, our findings suggest a role of miR-1 in the negative feedback loop in the regulation of contractility induced by myocardin.