Antidepressants with different mechanisms of action show different chronopharmacological profiles in the tail suspension test in mice.

The circadian system regulates sleep/wake cycles, metabolism, mood, and other functions. It also influences medication efficacy. In this study, we studied the chronopharmacological profiles of antidepressants with various modes of action. We also investigated the effects of dosing time on the pharmacological activity of several antidepressants acting on serotonergic, noradrenergic, and/or dopaminergic neurons. C57BL/6 mice were intraperitoneally administered fluoxetine, imipramine, venlafaxine, or bupropion at 08:00 h (morning), 14:00 h (mid-day), 20:00 h (evening), or 02:00 h (mid-night). Antidepressant activity was evaluated by the tail suspension test. All antidepressants reduced immobility, and their activities varied according to the dosing time. Fluoxetine and imipramine induced relatively strong rhythms with high amplitudes. Their maximal effects were observed in the morning and evening, respectively. Venlafaxine and bupropion induced weak rhythms with maximal effects in the evening and dawn, respectively. These results suggest that the antidepressant activity is associated with circadian fluctuation, and antidepressants with different modes of action have different chronopharmacological profiles. They affect locomotor activity in animals placed in novel (unfamiliar) environments. Fluoxetine, imipramine, and venlafaxine reduced locomotor activity, whereas bupropion increased it. The effects on locomotor activity also vary with circadian rhythm, and the tested drugs showed a maximal effect during the light phase. The peak time was different from that in TST. Plasma and brain levels of all drugs were slightly higher in the morning than in the evening. The dosing time dependency of the antidepressant activity did not correlate with the sedative/stimulatory activity or tissue drug level. Therefore, these latter two factors may have only a small impact on circadian antidepressant activity fluctuations. The relative activity of the serotonergic, noradrenergic, and dopaminergic systems may determine the chronopharmacological profiles of each drug. These results suggest the possibility that drug therapy be optimized by considering the dosing time when the antidepressant activity is high and other pharmacological activities leading to adverse effects are low. Further studies using animal models of depression and in clinical settings are necessary to confirm the effects of dosing time on depressed subjects.

High Expression of p62 Protein Is Associated with Poor Prognosis and Aggressive Phenotypes in Endometrial Cancer.

High expression of SQSTM1/p62 (p62) protein, which functions as a hub of oncogenic signaling pathways, has been detected in several human cancers. However, the clinicopathological and functional contribution of p62 expression is largely unknown in endometrial cancers (ECs). In this study, we assessed the expression status of p62 in primary ECs (n = 194) by immunohistochemistry and analyzed its clinical significance. Although p62 was expressed in the cytoplasm and/or nucleus in primary ECs, we observed that an expression subtype, high expression of cytoplasmic p62 but low expression of nuclear p62 (cytoplasm(High)/nucleus(Low)), significantly correlated with nonendometrioid types (P = 0.002), high grade (P < 0.001), deep myometrial invasion (P = 0.025), vascular invasion (P = 0.012), and poor prognosis (P < 0.001), and may be an independent prognostic marker of ECs (P = 0.011). Furthermore, RNA interference-mediated inhibition of p62 expression in the HEC-1A EC cell line led to the reduction of invasiveness and resistance to oxidative stress in vitro, as well as the suppression of in vivo tumor growth in an orthotopic mouse model of ECs. High expression of cytoplasmic p62 is a novel prognostic biomarker of ECs, and excess p62 expression may functionally contribute to the acquirement of malignant phenotypes in EC cells.

High Expression of SQSTM1/p62 Protein Is Associated with Poor Prognosis in Epithelial Ovarian Cancer.

High expression of SQSTM1/p62 (p62) protein, which functions as a hub for various cellular signaling pathways, has been detected in several human cancers. However, the clinicopathological impact of high p62 expression is largely unknown in epithelial ovarian cancer (EOC). Here, the expression level of p62 in primary EOCs (n=266) was assessed by immunohistochemistry, and its clinical significance was analyzed. Univariate and multivariate analyses were used to determine the impact of p62 expression on overall survival. p62 was expressed in the cytoplasm (Cyto) and/or nucleus (Nuc) in primary EOCs, and an expression subtype (Cyto(High)/Nuc(Low)), showing high expression in the cytoplasm but low expression in the nucleus, was significantly correlated with serous carcinoma (P<0.001), advanced stage (P=0.005), presence of residual tumor (P<0.001), and low overall survival rate (P=0.013). Furthermore, in serous carcinomas (n=107), the p62 Cyto(High)/Nuc(Low) subtype was significantly correlated with low overall survival rate (P=0.019) as an independent factor (P=0.044). Thus, our findings suggest that high expression of cytoplasmic p62 may be a novel prognostic biomarker in EOC, particularly in serous carcinoma.

Impairment of heme biosynthesis induces short circadian period in body temperature rhythms in mice.

It has been demonstrated that the function of mammalian clock gene transcripts is controlled by the binding of heme in vitro. To examine the effects of heme on biological rhythms in vivo, we measured locomotor activity (LA) and core body temperature (T(b)) in a mouse model of porphyria with impaired heme biosynthesis by feeding mice a griseofulvin (GF)-containing diet. Mice fed with a 2.0% GF-containing diet (GF2.0) transiently exhibited phase advance or phase advance-like phenomenon by 1-3 h in terms of the biological rhythms of T(b) or LA, respectively (both, P < 0.05) while mice were kept under conditions of a light/dark cycle (12 h:12 h). We also observed a transient, ~0.3 h shortening of the period of circadian T(b) rhythms in mice kept under conditions of constant darkness (P < 0.01). Interestingly, the observed duration of abnormal circadian rhythms in GF2.0 mice lasted between 1 and 3 wk after the onset of GF ingestion; this finding correlated well with the extent of impairment of heme biosynthesis. When we examined the effects of therapeutic agents for acute porphyria, heme, and hypertonic glucose on the pathological status of GF2.0 mice, it was found that the intraperitoneal administration of heme (10 mg·kg(-1)·day(-1)) or glucose (9 g·kg(-1)·day(-1)) for 7 days partially reversed (50%) increases in urinary δ-aminolevulinic acids levels associated with acute porphyria. Treatment with heme, but not with glucose, suppressed the phase advance (-like phenomenon) in the diurnal rhythms (P < 0.05) and restored the decrease of heme (P < 0.01) in GF2.0 mice. These results suggest that impairments of heme biosynthesis, in particular a decrease in heme, may affect phase and period of circadian rhythms in animals.

Manifestation of psychiatric behaviors in a mouse model of griseofulvin-induced hepatic porphyria.

Most patients with hepatic porphyria exhibit neuropsychiatric symptoms, including abdominal pain, peripheral neuropathy, confusion, insomnia and mental disturbances such as anxiety and depression. Although heme deficiency and accumulation of heme precursors are thought to be responsible for neuropsychiatric manifestations in patients with acute porphyria, the pathogenetic mechanisms remain poorly understood. In the present study, we observed psychiatric behaviors in mice with hepatic porphyria induced by the ingestion of a griseofulvin (GF)-containing diet over a period of 12 weeks. GF ingestion by the mice caused an accumulation of porphyrins in the feces and a decrease in heme in the liver; these effects were observed throughout the entire duration of the experiment, with maximum levels observed after circa 1 week of ingestion of this diet. In addition, the mice developed enlargement of the liver, hepatocyte injury, and cholestasis. Mice with hepatic porphyria manifested an anxiety-like behavior by the long-term treatment (over 5 weeks) in a GF-dose and duration dependent manner. The hepatic porphyria mice also manifested depression-like behaviors by the short-term treatment (3 weeks) of GF2.0, which was reversed by administration of anti-depressant, imipramine. In conclusion, this study for the first time demonstrated psychiatric manifestations in GF-induced hepatic porphyria mice. The present results suggest that model animals could be useful for elucidating the mechanisms underlying psychiatric manifestations in syndromes such as hepatic porphyria and hepatic encephalopathy that are associated with the impairment of hepatic function.