nNOS regulates ciliated cell polarity, ciliary beat frequency, and directional flow in mouse trachea.

Clearance of the airway is dependent on directional mucus flow across the mucociliary epithelium, and deficient flow is implicated in a range of human disorders. Efficient flow relies on proper polarization of the multiciliated cells and sufficient ciliary beat frequency. We show that NO, produced by nNOS in the multiciliated cells of the mouse trachea, controls both the planar polarity and the ciliary beat frequency and is thereby necessary for the generation of the robust flow. The effect of nNOS on the polarity of ciliated cells relies on its interactions with the apical networks of actin and microtubules and involves RhoA activation. The action of nNOS on the beat frequency is mediated by guanylate cyclase; both NO donors and cGMP can augment fluid flow in the trachea and rescue the deficient flow in nNOS mutants. Our results link insufficient availability of NO in ciliated cells to defects in flow and ciliary activity and may thereby explain the low levels of exhaled NO in ciliopathies

Neuronal nitric oxide synthase contributes to the regulation of hematopoiesis

Nitric oxide (NO) signaling is important for the regulation of hematopoiesis. However, the role of individual NO synthase (NOS) isoforms is unclear. Our results indicate that the neuronal NOS isoform (nNOS) regulates hematopolesis in vitro and in vivo. nNOS is expressed in adult bone marrow and fetal liver and is enriched in stromal cells. There is a strong correlation between expression of nNOS in a panel of stromal cell lines established from bone marrow and fetal liver and the ability of these cell lines to support hematopoietic stem cells; furthermore, NO donor can further increase this ability. The number of colonies generated in vitro from the bone marrow and spleen of nNOS-null mutants is increased relative to wild-type or inducible- or endothelial NOS knockout mice. These results describe a new role for nNOS beyond its action in the brain and muscle and suggest a model where nNOS, expressed in stromal cells, produces NO which acts as a paracrine regulator of hematopoietic stem cells

Behavior of adolescents of different experimental groups in the social interactions test.

<p>SDS – social defeat stress; PS – psychological stress; Light columns - empty cylinder; dark columns -unfamiliar partner is under cylinder. ***P<0.001 <i>vs</i> the controls of respective partners; +++P<0.001 <i>vs</i> SDS adolescents of respective partners; ##P<0.01; ###P<0.001 <i>vs</i> empty cylinder in respective groups (n = 10–12 per group).</p

Behavior of adolescents of different experimental groups in the partition test.

<p>SDS – social defeat stress; PS – psychological stress; Light columns - familiar partner; dark columns - unfamiliar partner; *P<0.05; **P<0.01; ***P<0.001 <i>vs</i> the controls of respective partners; +P<0.05; ++P<0.01; +++P<0.001 <i>vs</i> SDS adolescents of respective partners; #P<0.05; ##P<0.01; ###P<0.001 <i>vs</i> familiar partner in respective group (n = 10–12 per group).</p

Protocols for studying the effects of combined stress (SDS+SIS or CDS+SIS) on the behavior of adolescents (A) and adult mice stressed in adolescence (B).

<p>SDS - social defeat stress; CDS – communication deprivation stress; SIS – social instability stress. As a control age-matched groups of males living in littermate groups were used. Before being examined in a range of behavioral tests, control animals and adult mice at the period of 31–38 days (B) were placed in individual cages to facilitate behavioral testing and remove group housing effects. Experimental groups and age-matched control groups were tested simultaneously in the behavioral tests (one test per day). Details of protocol are described in section “Materials and methods”.</p

BrdU-positive cells in hippocampal subgranular zone of the dentate gyrus in SDS adolescents and in grown adolescents after 3 weeks of the rest.

<p>SDS – social defeat stress **P<0.01 - <i>vs</i> the controls (n = 6–7 per group).</p

Behavior of adolescents in the elevated plus-maze test.

<p>*P<0.05; **P<0.01 <i>vs</i> the control; ++P<0.01 <i>vs</i> SDS adolescents (n = 10–12 per group).</p

Behavior of adolescents of different experimental groups in the Porsolt test.

<p>SDS – social defeat stress; PS – psychological stress; **P<0.01 <i>vs</i> the controls. #P<0.05 <i>vs</i> SDS adolescents (n = 10–12 per group).</p