Takahito Miyake

Stimulation of transient receptor potential vanilloid 4 channel suppresses abnormal activation of microglia induced by lipopolysaccharide.

Microglia are intrinsic immune cells in the brain. In response to neurodegenerative events, excessively activated microglia change their shapes and release various cytokines leading to the pathogenesis of central nervous system (CNS) disease. Because the intracellular mechanisms of this process are still unclear, we have evaluated the functional roles of transient receptor potential vanilloid 4 (TRPV4) channel expressed in the microglia. Robust microglial activation after an injection of lipopolysaccharide (LPS) into the mouse cerebral ventricle was suppressed by concurrent administration of a selective TRPV4 agonist, 4α‐phorbol 12,13‐didecanoate (4α‐PDD). When the mechanism was further investigated using cultured rat microglia intrinsically expressing functional TRPV4, release of tumor necrosis factor‐α (TNF‐α) and expression of galectin‐3 were both increased by LPS. These increases were significantly suppressed by cotreatment with 4α‐PDD, and the inhibitory effects of 4α‐PDD were abolished by knockdown of TRPV4 or TRPV4 antagonists. The amplitude of voltage‐dependent K+ current, which is augmented during microglial activation, was also suppressed by 4α‐PDD treatment. Opening of TRPV4 channels with 4α‐PDD induced membrane depolarization mainly by increasing Na+ influx. In addition, mimicking depolarization with a high‐K+ solution suppressed LPS‐induced TNF‐α release and galectin‐3 upregulation. Both depolarizing treatments with 4α‐PDD and high‐K+ solution decreased store‐operated Ca2+ influx caused by thapsigargin. These results suggest that depolarization in response to opening of the TRPV4 channel attenuates the driving force for extracellular Ca2+ and suppresses microglial activation.

Transient Receptor Potential Canonical 3 Inhibitor Pyr3 Improves Outcomes and Attenuates Astrogliosis After Intracerebral Hemorrhage in Mice

Background and Purpose— Intracerebral hemorrhage (ICH) stems from the rupture of blood vessels in the brain, with the subsequent accumulation of blood in the parenchyma. Increasing evidence suggests that blood-derived factors induce excessive inflammatory responses that are involved in the progression of ICH-induced brain injury. Thrombin, a major blood-derived factor, leaks into the brain parenchyma on blood–brain barrier disruption and induces brain injury and astrogliosis. Furthermore, thrombin dynamically upregulates transient receptor potential canonical 3 channel, which contributes to pathological astrogliosis through a feed-forward upregulation of its own expression. The present study investigated whether Ethyl-1-(4-(2,3,3-trichloroacrylamide)phenyl)-5-(trifluoromethyl)-1H-pyrazole-4-carboxylate (Pyr3), a specific transient receptor potential canonical 3 inhibitor, can improve functional outcomes and attenuate astrogliosis after ICH in mice. Methods— Male C57BL6 mice received an intracerebral infusion of collagenase or autologous blood to induce ICH. Pyr3 was given both intracerebroventricularly and intraperitoneally after ICH induction. ICH-induced brain injury was evaluated by quantitative assessment of neurological deficits, brain swelling, and injury volume after ICH. Astrocyte activation was evaluated by immunohistochemical assessment of changes in S100 protein expression. Results— Neurological deficits, neuronal injury, brain edema, and astrocyte activation were all significantly improved by administration of Pyr3. Moreover, delayed administration of Pyr3 at 6 hours or 1 day after blood or collagenase infusion, respectively, also improved the symptoms. Conclusions— Pyr3, a specific inhibitor of transient receptor potential canonical 3, reduced the perihematomal accumulation of astrocytes and ameliorated ICH–induced brain injury. Therefore, transient receptor potential canonical 3 provides a new therapeutic target for the treatment of hemorrhagic brain injury.

TRPM2 contributes to LPS/IFNγ-induced production of nitric oxide via the p38/JNK pathway in microglia

Microglia are immune cells that maintain brain homeostasis at a resting state by surveying the environment and engulfing debris. However, in some pathological conditions, microglia can produce neurotoxic factors such as pro-inflammatory cytokines and nitric oxide (NO) that lead to neuronal degeneration. Inflammation-induced calcium (Ca(2+)) signaling is thought to underlie this abnormal activation of microglia, but the mechanisms are still obscure. We previously showed that combined application of lipopolysaccharide and interferon γ (LPS/IFNγ) induced-production of NO in microglia from wild-type (WT) mice is significantly reduced in microglia from transient receptor potential melastatin 2 (TRPM2)-knockout (KO) mice. Here, we found that LPS/IFNγ produced a late-onset Ca(2+) signaling in WT microglia, which was abolished by application of the NADPH oxidase inhibitor diphenylene iodonium (DPI) and ML-171. In addition, pharmacological blockade or gene deletion of TRPM2 channel in microglia did not show this Ca(2+) signaling. Furthermore, pharmacological manipulation and Western blotting revealed that Ca(2+) mobilization, the proline-rich tyrosine kinase 2 (Pyk2), p38 mitogen-activated protein kinase (p38 MAPK) and c-Jun NH2-terminal kinase (JNK) contributed to TRPM2-mediated LPS/IFNγ-induced activation, while the extracellular signal-regulated protein kinase (ERK) did not. These results suggest that LPS/IFNγ activates TRPM2-mediated Ca(2+) signaling, which in turn increases downstream p38 MAPK and JNK signaling and results in increased NO production in microglia.

Cold sensitivity of TRPA1 is unveiled by the prolyl hydroxylation blockade-induced sensitization to ROS

Mammalian transient receptor potential ankyrin 1 (TRPA1) is a polymodal nociceptor that plays an important role in pain generation, but its role as a cold nociceptor is still controversial. Here, we propose that TRPA1 can sense noxious cold via transduction of reactive oxygen species (ROS) signalling. We show that inhibiting hydroxylation of a proline residue within the N-terminal ankyrin repeat of human TRPA1 by mutation or using a prolyl hydroxylase (PHD) inhibitor potentiates the cold sensitivity of TRPA1 in the presence of hydrogen peroxide. Inhibiting PHD in mice triggers mouse TRPA1 sensitization sufficiently to sense cold-evoked ROS, which causes cold hypersensitivity. Furthermore, this phenomenon underlies the acute cold hypersensitivity induced by the chemotherapeutic agent oxaliplatin or its metabolite oxalate. Thus, our findings provide evidence that blocking prolyl hydroxylation reveals TRPA1 sensitization to ROS, which enables TRPA1 to convert ROS signalling into cold sensitivity.

Activation of mitochondrial transient receptor potential vanilloid 1 channel contributes to microglial migration

Microglia, the resident immune cells in the brain, survey the environment of the healthy brain. Microglial migration is essential for many physiological and pathophysiological processes. Although microglia express some members of the transient receptor potential (TRP) channel family, there is little knowledge regarding the physiological roles of TRP channels in microglia. Here, we explored the role of TRP vanilloid 1 (TRPV1), a channel opened by capsaicin, heat, protons, and endovanilloids, in microglia. We found that application of capsaicin induced concentration‐dependent migration in microglia derived from wild‐type mice but not in those derived from TRPV1 knockout (TRPV1‐KO) mice. Capsaicin‐induced microglial migration was significantly inhibited by co‐application of the TRPV1 blocker SB366791 and the Ca2+ chelator BAPTA‐AM. Using RT‐PCR and immunocytochemistry, we validated that TRPV1 was expressed in microglia. Electrophysiological recording, intracellular Ca2+ imaging, and immunocytochemistry indicated that TRPV1 was localized primarily in intracellular organelles. Treatment with capsaicin induced an increase in intramitochondrial Ca2+ concentrations and mitochondrial depolarization. Furthermore, microglia derived from TRPV1‐KO mice showed delayed Ca2+ efflux compared with microglia derived from wild‐type mice. Capsaicin‐induced microglial migration was inhibited by membrane‐permeable antioxidants and MAPK inhibitors, suggesting that mitochondrial TRPV1 activation induced Ca2+‐dependent production of ROS followed by MAPK activation, which correlated with an augmented migration of microglia. Moreover, a mixture of three endovanilloids augmented microglial migration via TRPV1 activation. Together, these results indicate that mitochondrial TRPV1 plays an important role in inducing microglial migration. Activation of TRPV1 triggers an increase in intramitochondrial Ca2+ concentration and following depolarization of mitochondria, which results in mtROS production, MAPK activation, and enhancement of chemotactic activity in microglia. GLIA 2015;63:1870–1882

Significance of histologic pattern of carcinoma and sarcoma components on survival outcomes of uterine carcinosarcoma

BACKGROUNDnTo examine the effect of the histology of carcinoma and sarcoma components on survival outcome of uterine carcinosarcoma.nnnPATIENTS AND METHODSnA multicenter retrospective study was conducted to examine uterine carcinosarcoma cases that underwent primary surgical staging. Archived slides were examined and histologic patterns were grouped based on carcinoma (low-grade versus high-grade) and sarcoma (homologous versus heterologous) components, correlating to clinico-pathological demographics and outcomes.nnnRESULTSnAmong 1192 cases identified, 906 cases were evaluated for histologic patterns (carcinoma/sarcoma) with high-grade/homologous (40.8%) being the most common type followed by high-grade/heterologous (30.9%), low-grade/homologous (18.0%), and low-grade/heterologous (10.3%). On multivariate analysis, high-grade/heterologous (5-year rate, 34.0%, P = 0.024) and high-grade/homologous (45.8%, P = 0.017) but not low-grade/heterologous (50.6%, P = 0.089) were independently associated with decreased progression-free survival (PFS) compared with low-grade/homologous (60.3%). In addition, older age, residual disease at surgery, large tumor, sarcoma dominance, deep myometrial invasion, lymphovascular space invasion, and advanced-stage disease were independently associated with decreased PFS (all, P < 0.01). Both postoperative chemotherapy (5-year rates, 48.6% versus 39.0%, P < 0.001) and radiotherapy (50.1% versus 44.1%, P = 0.007) were significantly associated with improved PFS in univariate analysis. However, on multivariate analysis, only postoperative chemotherapy remained an independent predictor for improved PFS [hazard ratio (HR) 0.34, 95% confidence interval (CI) 0.27-0.43, P < 0.001]. On univariate analysis, significant treatment benefits for PFS were seen with ifosfamide for low-grade carcinoma (82.0% versus 49.8%, P = 0.001), platinum for high-grade carcinoma (46.9% versus 32.4%, P = 0.034) and homologous sarcoma (53.1% versus 38.2%, P = 0.017), and anthracycline for heterologous sarcoma (66.2% versus 39.3%, P = 0.005). Conversely, platinum, taxane, and anthracycline for low-grade carcinoma, and anthracycline for homologous sarcoma had no effect on PFS compared with non-chemotherapy group (all, P > 0.05). On multivariate analysis, ifosfamide for low-grade/homologous (HR 0.21, 95% CI 0.07-0.63, P = 0.005), platinum for high-grade/homologous (HR 0.36, 95% CI 0.22-0.60, P < 0.001), and anthracycline for high-grade/heterologous (HR 0.30, 95% CI 0.14-0.62, P = 0.001) remained independent predictors for improved PFS. Analyses of 1096 metastatic sites showed that carcinoma components tended to spread lymphatically, while sarcoma components tended to spread loco-regionally (P < 0.001).nnnCONCLUSIONnCharacterization of histologic pattern provides valuable information in the management of uterine carcinosarcoma.

Second-line chemotherapy for advanced or recurrent endometrial carcinoma previously treated with paclitaxel and carboplatin, with or without epirubicin

PurposeA combined chemotherapy of taxane and platinum, with or without anthracycline, has been used as a standard first-line regimen. The purpose of this study was to investigate the effectiveness of second-line chemotherapy for treatment of advanced or recurrent endometrial carcinoma previously treated with a combined chemotherapy of taxane and platinum, with or without anthracycline.MethodsDuring the 2000–2008 study period, 723 patients were diagnosed with endometrial cancer at the Departments of Obstetrics and Gynecology of the Osaka University and the Osaka Rosai Hospitals, Osaka, Japan. The subset of these cases that eventually required treatment by second-line chemotherapy was retrospectively analyzed.ResultsResponse rate to second-line chemotherapy was 25%. Treatment-free interval (TFI) of ≥xa0orxa0<6xa0months was demonstrated to be significantly associated with the response to second-line chemotherapy (Pxa0=xa00.0026), progression-free survival (Pxa0=xa00.0003) and overall survival (Pxa0=xa00.025). The second-line chemotherapy similar to the first-line regimen was ineffective in all the 7 cases (100%) whose TFI was shorter than 6xa0months. Multivariate analysis showed that TFI was the most significantly important factor predicting the effectiveness of second-line chemotherapy (the adjusted hazard ratio of TFI on PFS and OS: 3.482, 95% CI, 1.641–7.388, Pxa0=xa00.0012, and 2.341, 95% CI, 1.034–5.301, Pxa0=xa00.042, respectively).ConclusionsOur present study provides, for the first time, evidence that the majority of refractory or recurrent diseases, if they occur within 6xa0months of a first-line chemotherapy using taxane and platinum with or without anthracycline, are non-responsive to the current regimens of second-line chemotherapy.

Impact of adjuvant therapy on recurrence patterns in stage I uterine carcinosarcoma

BACKGROUNDnTo examine recurrence patterns in women with stage I uterine carcinosarcoma (UCS) stratified by adjuvant therapy pattern.nnnMETHODSnWe examined 443 cases of stage I UCS derived from a retrospective cohort of 1192 UCS cases from 26 institutions. Adjuvant therapy patterns after primary hysterectomy-based surgery were correlated to recurrence patterns.nnnRESULTSnThe most common adjuvant therapy was chemotherapy alone (41.5%) followed by chemotherapy/radiotherapy (15.8%) and radiotherapy alone (8.4%). Distant-recurrence was the most common recurrence pattern (5-year cumulative rate, 28.1%) followed by local-recurrence (13.3%). On multivariate analysis, chemotherapy but not radiotherapy remained an independent prognostic factor for decreased risk of local-recurrence (5-year cumulative rates 8.7% versus 19.8%, adjusted-hazard ratio [HR] 0.46, 95% confidence interval [CI] 0.25-0.83, P=0.01) and distant-recurrence (21.2% versus 38.0%, adjusted-HR 0.41, 95%CI 0.27-0.62, P<0.001). The chemotherapy/radiotherapy group had a lower 5-year cumulative local-recurrence rate compared to the chemotherapy alone group but it did not reach statistical significance (5.1% versus 10.1%, adjusted-HR 0.46, 95%CI 0.13-1.58, P=0.22). Radiotherapy significantly decreased local-recurrence when tumors had high-grade carcinoma, sarcoma component dominance, and deep myometrial tumor invasion (all, P<0.05); and combining radiotherapy with chemotherapy was significantly associated with decreased local-recurrence compared to chemotherapy alone in the presence of multiple risk factors (5-year cumulative rates, 2.5% versus 21.8%, HR 0.12, 95%CI 0.02-0.90; P=0.013) but not in none/single factor (P=0.36).nnnCONCLUSIONnAdjuvant chemotherapy appears to be effective to control both local- and distant-recurrences in stage I UCS; adding radiotherapy to chemotherapy may be effective to control local-recurrence when the tumor exhibits multiple risk factors.

Postpartum Outcome of Cervical Intraepithelial Neoplasia in Pregnant Women Determined by Route of Delivery

Cervical intraepithelial neoplasia (CIN) has its highest incidence during women’s reproductive years. During 2 sequential 7-year periods, 1994 to 2000 and 2001 to 2007, 3695 and 3894 deliveries were performed, respectively, at Osaka University Hospital. CIN was detected in 21 cases (0.57%) during 1994-2000 and in 43 cases (1.1%) during 2001-2007. By comparison, cervical intraepithelial neoplasia—complicated pregnancies increased significantly in the latter period (P = .015 by Fisher exact test, Odds ratio = 1.95; 95%CI: 1.16-3.30). We observed CIN regression in 34 (76%) of 45 cases of vaginal delivery and in 6 (50%) of 12 cases of cesarean delivery, indicating that the outcome of an initially diagnosed CIN and the delivery routes appeared not to be significantly related. However, a different result was obtained when only those patients whose CIN lesions persisted until the delivery were analyzed. Among the 35 such cases in the vaginal delivery group, 24 cases (69%) regressed after the delivery; in 8 such cases from the cesarean delivery group, only 2 cases (25%) regressed afterward. Our study clearly shows that pregnancy complicated with CIN is increasing rapidly in Japan. We also find that there is a significantly more frequent postpartum regression of biopsy-proven CIN lesions following a vaginal delivery compared to cesarean section (P = .042 by Fisher exact test, Odds ratio = 6.55; 95% CI: 1.13-37.8).

Hypoxia-induced sensitisation of TRPA1 in painful dysesthesia evoked by transient hindlimb ischemia/reperfusion in mice

Dysesthesia is an unpleasant abnormal sensation, which is often accompanied by peripheral neuropathy or vascular impairment. Here, we examined the roles of transient receptor potential ankyrin 1 (TRPA1) in dysesthesia-like behaviours elicited by transient hindlimb ischemia (15–60u2009min) by tightly compressing the hindlimb, and reperfusion by releasing the ligature. The paw-withdrawal responses to tactile stimulation were reduced during ischemia and lasted for a while after reperfusion. Hindlimb ischemia/reperfusion elicited spontaneous licking of the ischemic hindpaw that peaked within 10u2009min. The licking was inhibited by reactive oxygen species (ROS) scavengers, a TRPA1 antagonist, or TRPA1 deficiency, but not by TRPV1 deficiency. In human TRPA1-expressing cells as well as cultured mouse dorsal root ganglion neurons, the H2O2-evoked TRPA1 response was significantly increased by pretreatment with hypoxia (80u2009mmHg) for 30u2009min. This hypoxia-induced TRPA1 sensitisation to H2O2 was inhibited by overexpressing a catalytically-inactive mutant of prolyl hydroxylase (PHD) 2 or in a TRPA1 proline mutant resistant to PHDs. Consistent with these results, a PHD inhibitor increased H2O2-evoked nocifensive behaviours through TRPA1 activation. Our results suggest that transient hindlimb ischemia/reperfusion-evoked spontaneous licking, i.e. painful dysesthesia, is caused by ROS-evoked activation of TRPA1 sensitised by hypoxia through inhibiting PHD-mediated hydroxylation of a proline residue in TRPA1.