Epigenetic regulation contributes to urocortin-enhanced midbrain dopaminergic neuron differentiation.

The production of midbrain dopaminergic (mDA) neurons requires precise extrinsic inductive signals and intrinsic transcriptional cascade at a specific time point in development. Urocortin (UCN) is a peptide of the corticotropin-releasing hormone family that mediates various responses to stress. UCN was first cloned from adult rat midbrain. However, the contribution of UCN to the development of mDA neurons is poorly understood. Here, we show that UCN is endogenously expressed in the developing ventral midbrain (VM) and its receptors are exhibited in Nurr1(+) postmitotic mDA precursors and TH(+) neurons, suggesting possible roles in regulating their terminal differentiation. UCN treatment increased DA cell numbers in rat VM precursor cultures by promoting the conversion of Nurr1(+) precursors into DA neurons. Furthermore, neutralization of secreted UCN with anti-UCN antibody resulted in a reduction in the number of DA neurons. UCN induced an abundance of acetylated histone H3 and enhanced late DA regulator Nurr1, Foxa2, and Pitx3 expressions. Using pharmacological and RNA interference approaches, we further demonstrated that histone deacetylase (HDAC) inhibition and late transcriptional factors upregulation contribute to UCN-mediated DA neuron differentiation. Chromatin immunoprecipitation analyses revealed that UCN promoted histone acetylation of chromatin surrounding the TH promoter by directly inhibiting HDAC and releasing of methyl CpG binding protein 2-CoREST-HDAC1 repressor complex from the promoter, ultimately leading to an increase in Nurr1/coactivators-mediated transcription of TH gene. Moreover, UCN treatment in vivo also resulted in increased DA neuron differentiation. These findings suggest that UCN might contribute to regulate late mDA neuron differentiation during VM development.

Histone deacetylase inhibition mediates urocortin-induced antiproliferation and neuronal differentiation in neural stem cells.

During cortical development, cell proliferation and cell cycle exit are carefully regulated to ensure that the appropriate numbers of cells are produced. Urocortin (UCN) is a member of the corticotrophin releasing hormone (CRH) family of neuropeptides that regulates stress responses. UCN is widely distributed in adult rat brain. However, the expression and function of UCN in embryonic brain is, as yet, unclear. Here, we show that UCN is endogenously expressed in proliferative zones of the developing cerebral cortex and its receptors are exhibited in neural stem cells (NSCs), thus implicating the neuropeptide in cell cycle regulation. Treatment of cultured NSCs or organotypic slice cultures with UCN markedly reduced cell proliferation. Furthermore, blocking of endogenous UCN/CRHRs system either by treatment with CRHRs antagonists or by neutralization of secreted UCN with anti-UCN antibody increased NSCs proliferation. Cell cycle kinetics analysis demonstrated that UCN lengthened the total cell cycle duration via increasing the G1 phase and accelerated cell cycle exit. UCN directly inhibited the histone deacetylase (HDAC) activity and induced a robust increase in histone H3 acetylation levels. Using pharmacological and RNA interference approaches, we further demonstrated that antiproliferative action of UCN appeared to be mediated through a HDAC inhibition-induced p21 upregulation. Moreover, UCN treatment in vitro and in vivo led to an increase in neuronal differentiation of NSCs. These findings suggest that UCN might contribute to regulate NSCs proliferation and differentiation during cortical neurogenesis.

Health-Related Quality of Life and Medical Resource Use in Patients with Osteoporosis and Depression: A Cross-Sectional Analysis from the National Health and Nutrition Examination Survey.

Background: Patients with either osteoporosis or depression are prone to develop other diseases and require more medical resources than do the general population. However, there are no studies on health-related quality of life (HRQoL) and medical resource use by osteoporosis patients with comorbid depression. We conducted this study for clarifying it. Methods: This cross-sectional study from 2005 to 2010 (6 years) analyzed 9776 National Health and Nutrition Examination Survey (NHANES) patients > 40 years old. Each patient was assigned to one of four groups: osteoporosis-positive(+) and depression-positive(+) (O+/D+); O+/D-; O-/D+; O-/D-. We used multivariate linear and logistic regression model to analyze the HRQoL and medical resource use between groups. Results: The O+/D+ group reported more unhealthy days of physical health, more unhealthy days of mental health, and more inactive days during a specified 30 days. The adjusted odds ratios (AORs) of O+/D+ patients who had poor general health (7.40, 95% CI = 4.80-11.40), who needed healthcare (3.25, 95% CI = 2.12-5.00), and who had been hospitalized overnight (2.71, 95% CI = 1.89-3.90) were significantly highest. Conclusions: Low HRQoL was significantly more prevalent in D+/O+ patients. We found that depression severity more significantly affected HRQoL than did osteoporosis. However, both diseases significantly increased the risk of high medical resource use.

Acute effects of nicotine on restraint stress-induced anxiety-like behavior, c-Fos expression, and corticosterone release in mice.

Clinical evidence suggests that nicotine reduces anxiety in stressful situations. In the present study, we investigated the effect of nicotine on restraint-enhanced anxiety-like behavior, c-Fos expression, an index of neuronal activation in the brain, and plasma corticosterone. Two-hour restraint stress-enhanced anxiety-like behavior in the elevated plus-maze (EPM) and nicotine hydrogen tartrate (0.25 mg/kg, i.p.) attenuated the stress-induced changes. Pretreatment with the centrally acting nicotinic antagonist, mecamylamine (2 mg/kg), blocked nicotine's effects. In addition, restraint led to significant increases of c-Fos expression in several brain regions related to stress or anxiety including paraventricular hypothalamic nucleus (PVN), lateral hypothalamic area (LH), central amygdaloid nucleus (CeA), medial amygdaloid nucleus (MeA) and cingulate and retrosplenial cortices (Cg/RS), paraventricular thalamic nucleus (PVT), and basolateral amygdaloid nucleus (BLA). Nicotine attenuated the restraint-induced expression of c-Fos in the PVN, LH, CeA, MeA, and Cg/RS, while leaving the BLA and PVT unaffected. In contrast, nicotine did not reverse the increased levels of plasma corticosterone induced by restraint. These findings suggest that nicotine may modify the stress-induced behavioral changes via regulating the neuronal activation in selected brain regions rather than affecting hypothalamo-pituitary-adrenocortical axis hormone responses.

Behavioural and toxic interaction profile of ketamine in combination with caffeine.

Ketamine street tablets often contain several other compounds in addition to ketamine, among them is caffeine. The purpose of this study was to examine whether caffeine interacts with ketamine-induced behavioural and toxic effects. Male ICR mice were treated with ketamine alone or ketamine combined with various doses of caffeine, then the locomotor activity, rotarod test, prepulse inhibition of acoustic startle, loss of righting reflex, and mortality rate were examined. Caffeine enhanced the locomotor hyperactivity, caused disruption of the rotarod performance, and mortality rates due to ketamine, whereas prepulse inhibition deficits and anaesthesia remained unaffected. These findings demonstrate that use of ketamine in combination with caffeine enhances its stimulant responses and lethal risk, suggesting that a potentially toxic interaction exists between ketamine and caffeine.

Transdermal delivery of proteins mediated by non-covalently associated arginine-rich intracellular delivery peptides.

Plasma membranes of animal cells are generally impermeable to macromolecules. Protein transduction mediated by protein transduction domains (PTDs) covalently cross-linked to cargoes for cellular internalization has previously been demonstrated. Peptides with PTDs could be an effective way to deliver proteins into living cells or tissues in vitro. In this report, we demonstrate that arginine-rich intracellular delivery (AID) peptides are able to facilitate the delivery of proteins into animal cells and to penetrate skin tissues rapidly. This cellular internalization and transdermal delivery of proteins is mediated by non-toxic AID peptides in a non-fusion protein and non-conjugation dependent manner. The efficiency of intracellular transport is further increased in the presence of chemical enhancer oleic acid. The mechanism of the AID-mediated cellular entry may involve macropinocytosis and actin rearrangement. Thus, we confirm that direct delivery of bioactive proteins into living cells and tissues mediated by non-covalent actions of AID peptides represents a useful strategy in pharmaceutics, therapeutics and cosmetics.

Arginine-rich intracellular delivery peptides noncovalently transport protein into living cells.

Plasma membranes of plant or animal cells are generally impermeable to peptides or proteins. Many basic peptides have previously been investigated and covalently cross-linked with cargoes for cellular internalization. In the current study, we demonstrate that arginine-rich intracellular delivery (AID) peptides are able to deliver fluorescent proteins or beta-galactosidase enzyme into animal and plant cells, as well as animal tissue. Cellular internalization and transdermal delivery of protein could be mediated by effective and nontoxic AID peptides in a neither fusion protein nor conjugation fashion. Therefore, noncovalent AID peptides may provide a useful strategy to have active proteins function in living cells and tissues in vivo.