tautomycin and Disease-Models--Animal

Wound healing is a complex sequence of cellular and molecular processes such as inflammation, cell migration, proliferation and differentiation. ROCK is a widely investigated Ser/Thr kinase with important roles in rearranging the actomyosin cytoskeleton. ROCK inhibitors have already been approved to improve corneal endothelial wound healing. The purpose of this study was to investigate the functions of myosin phosphatase (MP or PPP1CB), a type-1 phospho-Ser/Thr-specific protein phosphatase (PP1), one of the counter enzymes of ROCK, in skin homeostasis and wound healing. To confirm our hypotheses, we applied tautomycin (TM), a selective PP1 inhibitor, on murine skin that caused the arrest of wound closure. TM suppressed scratch closure of HaCaT human keratinocytes without having influence on the survival of the cells. Silencing of, the regulatory subunit of MP (MYPT1 or PPP1R12A), had a negative impact on the migration of keratinocytes and it influenced the cell-cell adhesion properties by decreasing the impedance of HaCaT cells. We assume that MP differentially activates migration and differentiation of keratinocytes and plays a key role in the downregulation of transglutaminase-1 in lower layers of skin where no differentiation is required. MAPK Proteome Profiler analysis on human ex vivo biopsies with MYPT1-silencing indicated that MP contributes to the mediation of wound healing by regulating the Akt signaling pathway. Our findings suggest that MP plays a role in the maintenance of normal homeostasis of skin and the process of wound healing.

Topics: Animals; Cell Adhesion; Cell Differentiation; Cell Line; Cell Movement; Cell Proliferation; Disease Models, Animal; Homeostasis; Humans; Keratinocytes; Mice; Myosin-Light-Chain Phosphatase; Protein Phosphatase 1; Proto-Oncogene Proteins c-akt; Pyrans; Signal Transduction; Spiro Compounds; Transglutaminases; Wound Healing

Protein kinases and phosphatases can alter the impact of excitotoxicity resulting from ischemia by concurrently modulating apoptotic/survival pathways. Here, we show that protein phosphatase 1 (PP1), known to constrain neuronal signaling and synaptic strength (Mansuy et al., 1998; Morishita et al., 2001), critically regulates neuroprotective pathways in the adult brain. When PP1 is inhibited pharmacologically or genetically, recovery from oxygen/glucose deprivation (OGD) in vitro, or ischemia in vivo is impaired. Furthermore, in vitro, inducing LTP shortly before OGD similarly impairs recovery, an effect that correlates with strong PP1 inhibition. Conversely, inducing LTD before OGD elicits full recovery by preserving PP1 activity, an effect that is abolished by PP1 inhibition. The mechanisms of action of PP1 appear to be coupled with several components of apoptotic pathways, in particular ERK1/2 (extracellular signal-regulated kinase 1/2) whose activation is increased by PP1 inhibition both in vitro and in vivo. Together, these results reveal that the mechanisms of recovery in the adult brain critically involve PP1, and highlight a novel physiological function for long-term potentiation and long-term depression in the control of brain damage and repair.

Topics: Animals; Animals, Genetically Modified; Brain Ischemia; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Disease Models, Animal; Dose-Response Relationship, Drug; Dose-Response Relationship, Radiation; Doxycycline; Electric Stimulation; Enzyme Inhibitors; Gene Expression Regulation; Glucose; Hippocampus; Hypoxia; In Vitro Techniques; Long-Term Synaptic Depression; Mice; Mice, Inbred C57BL; Neuronal Plasticity; Protein Phosphatase 1; Proteins; Pyrans; Recovery of Function; Spiro Compounds