A web of imprinting in stem cells

Imprinted genes are the prototypical epigenetically regulated genes. On the basis of findings in adult lung stem cells, Zacharek et?al. (2011) suggest in this issue of Cell Stem Cell that epigenetic silencing of imprinted genes is a common requirement for maintaining self-renewal in adult stem cell populations.     

Pluripotency takes off without Blimp1

The innate capacity of adult somatic cells has many potential applications in regenerative medicine. In this issue of Cell Stem Cell, Salero et al. (2012) describe an adult retinal stem cell population capable of generating neural and mesenchymal cell lineages.     

Waste management and adult neurogenesis

Dying cells are common in adult neurogenic niches, but how these cells are cleared remains uncertain. In this issue of Cell Stem Cell, Sierra et al. (2010) show that unactivated microglia assume the role of waste managers to eliminate cellular debris from apoptosing newborn cells in the hippocampus.     

Adult neurogenesis: VCAM stems the tide

In this issue of Cell Stem Cell, Kokovay et?al. uncover that VCAM1 expression in neural stem cells regulates adult neurogenesis. Cerebrospinal fluid-borne IL-1β upregulates VCAM1 expression, which in turn regulates the architecture of the stem cell niche, redox homeostasis, and neurogenesis.     

Self-renewal in the fly kidney

Tissue stem cells are typically rare and located in niches that prescribe low rates of cell division and survival. In the latest issue of Cell Stem Cell, Singh et al. (2007) demonstrate that, in the adult fly, epithelial cells exist that are neither in niches nor in small numbers, divide at high rates, and are multipotent.     

The pessimist's and optimist's views of adult neurogenesis

The reports by Bonaguidi et?al. (in this issue of Cell) and Encinas et?al. (in Cell Stem Cell) come to differing conclusions about whether and how the proliferation of radial glia-like stem cells of the adult hippocampus impacts their long-term potential for neurogenesis.     

Rewind to recover: dedifferentiation after cardiac injury

In adult mammals, cardiomyocytes are known to reactivate an embryonic gene-expression program after injury. In this issue of Cell Stem Cell, Kubin et al. (2011) show that oncostatin M regulates this dedifferentiation which, while beneficial for recovery from acute injury, if persistent results in heart failure in both rodents and humans.     

Committing to a hairy fate: epigenetic regulation of hair follicle stem cells

Chromatin modifications are important for embryonic stem cell (ESC) pluripotency, but their functions in adult stem cells are less clear. In this issue of Cell Stem Cell, Lien et?al. (2011) delineate histone methylation patterns in hair follicle stem cells and show that these marks differ from those of ESCs.     

Kinship and Descent: Redefining the Stem Cell Compartment in the Adult Hippocampus

Identifying multipotent, self-renewing neural stem cells (NSCs) within the adult hippocampus in vivo has been somewhat elusive. In this issue of Cell Stem Cell, Suh et al. (2007) show that Sox2-expressing cells in the subgranular zone (SGZ) of the dentate gyrus not only have NSC characteristics but also display an unexpected degree of heterogeneity.     

Tracing the life of the kidney tubule- re-establishing dogma and redirecting the options

Renal pathology suggests that tubular repair results from tubular proliferation. In contrast, recent studies propose that postnatal kidney repair may involve renal stem cells. In this issue of Cell Stem Cell, Humphreys et al. (2008) use lineage tracing to genetically assess contribution of adult nontubular cells (potentially stem cells) to repair of damaged renal tubules.     

Aging within the Stem Cell niche

Decreased adult stem cell function is thought to play a primary role in organismal aging. Two recent papers in Cell Stem Cell demonstrate the importance of signaling from the stem cell niche in the aging of Drosophila germline stem cells.     

The hormone of love attracts a partner for life

Neurovascular integration during embryonic development is essential for adult physiology. In this issue of Developmental Cell, Gutnick et?al. (2011) report that hypothalamic neurons secrete oxytocin as a guidance cue for endothelial cells to establish their vascular supply-a prerequisite for neuroendocrine secretion from the neurohyophysis in adult life.     

Hope for a broken heart?

Heated debate has surrounded the issue of whether adult stem cells can differentiate into cardiac myocytes and contribute to the function of the heart. In this issue of Cell, demonstrate stem cells in the adult rat heart that differentiate into cardiac myocytes in vitro and, when injected into the adult rat heart, can reconstitute the injured myocardium and improve function. These findings should weigh heavily in future debates about the existence of stem cells in the adult heart and their capacity for functional repair after injury.     

Intraperineural localization of lamellated sensory corpuscles in the skin and oral mucosae of the adult cat and miniature pig

Brain Cell Biology - Lamellated sensory corpuscles in the perioral tissues of the adult cat and the adult miniature pig were studied by light and electron microscopy. In the cat lip, over half of...     

Three-dimensional scanning electron microscopic study of the normal hamster olfactory epithelium

Brain Cell Biology - The olfactory epithelium of the adult hamster (Mesocricetus auratus) was studied using the scanning electron microscope. A method that produced fractures in the epithelium...     

Home is where the heart is: via the FROUNT

In this issue of Cell Stem Cell, Belema-Bedada et al. (2008) describe a novel mechanism by which bone marrow-derived adult mesenchymal stem cells migrate to sites of damaged heart tissue. This process is dependent on the intracellular adaptor molecule FROUNT, which interacts with the chemokine receptor CCR2.     

Emerging parallels in the generation and regeneration of skeletal muscle

Previously, skeletal muscle regeneration appeared to be very different from embryonic specification of muscle, but in this issue of Cell, Polesskaya et al. show that Wnt signaling induces myogenesis in adult muscle stem cells in a manner analogous to muscle induction in the somite.     

Insulin induces changes in the subcellular distribution of actin and 5′-nucleotidase

The present study utilized a cultured adult myocardial cell model to examine the arachidonic acid metabolism under different cell-damaging and normoxic conditions. Cell injury was caused by short-time hypoxia, calcium ionophore A 23187-triggered cell-damage under hypoxia and cell disruption by freezing and thawing. The current study demonstrates that under the cell-damaging conditions cultured adult heart myocytes resemble myocardial cells under normoxic conditions in metabolizing arachidonic acid into triacylglycerols and phospholipids as the major route (a), in formation of ETYA-inhibitable indomethacin-resistant lipid metabolites in minor amounts (b) and in being independent of calcium overload in the metabolic pathways of arachidonic acid metabolism (c). The ETYA-inhibitable components were resolved by HPLC. There was no evidence in formation of lipoxygenase products. The results were supported by negative hybridisation experiments of the total mRNA isolated from adult myocardial cells with a cDNA probe of a red-cell-specific lipoxygenase mRNA. We conclude from these observations that cell injury does not result in expression of lipoxygenase activities in heart myocytes.Abbreviations HETE Hydroxyeicosatetraenoic acid - DiHETE Dihydroxyeicosatetraenoic acid - ETYA 5.8.11.14-Eicosatetraynoic acid - TLC Thin-Layer Chromatography - NP-HPLC Normal Phase-High Performance Liquid Chromatography - RBC Red Blood Cell - LOX Lipoxygenase