Neuroprotective effect of low-dose paracetamol treatment against cognitive dysfunction in d-galactose-induced aging mice.

Background: Aging is closely associated to several deleterious conditions and cognitive impairment. Administration of low-dose paracetamol (APAP) has previously been reported to improve cognitive performance in both human and animal studies. However, the altered cognitive effects of low-dose APAP treatment in the aging brain have not been elucidated. Objectives: The purpose of this study was to determine whether low-dose APAP treatment improves cognitive dysfunction in a d-galactose (d-gal)-induced aging model. Materials and methods: APAP (15 and 50 mg/kg p.o.) and vitamin E (Vit E 100 mg/kg p.o.) were administered once daily to d-gal-injected mice (200 mg/kg s.c.) for 6 weeks. The elevated plus maze (EPM), open field, novel object recognition (NOR), and Morris water maze (MWM) tests, respectively, were used to measure altered neurobehavioral functions, including anxiety-like behavior and exploratory locomotor activity, as well as learning and memory performance. The gene transcription of brain-derived neurotrophic factor (BDNF)/tropomyosin receptor kinase B (TrkB) signaling in brain tissues was evaluated by real-time polymerase chain reaction. Results: Compared to the control, d-gal significantly decreased exploratory locomotor activity and NOR and MWM performance but did not significantly change the activity in the EPM test. However, APAP50 and Vit E significantly reversed the effects of d-gal injection on exploratory locomotor activity. In addition, low-dose APAP (15 and 50 mg/kg) and Vit E significantly improved the reduction in NOR and MWM performance induced by d-gal. Real-time polymerase chain reaction analysis revealed that the mRNA expression of BDNF, neurotrophic tyrosine receptor kinase (NTRK), which is the gene coding TrkB receptor, and cAMP response element-binding protein (CREB) was significantly decreased in the frontal cortex and hippocampus of the d-gal mice. However, APAP50 and Vit E significantly increased BDNF and NTRK mRNA expression in both the frontal cortex and the hippocampus. A lower dose of APAP (15 mg/kg) significantly elevated the mRNA expression of NTRK, but only in the hippocampus. Moreover, APAP50 significantly increased CREB mRNA expression in the frontal cortex and hippocampus. Conclusion: Low-dose APAP treatment has a neuroprotective effect on cognitive dysfunction in the d-gal aging model, and the underlying molecular mechanisms depend on the activation of BDNF/TrkB signaling.

Actin Polymerization Is Required for Filopodia Formation Supporting HSV-1 Entry into Activated T Cells.

Enhanced HSV-1 production is found in activated T-lymphocytes, but the mechanism is still unknown. In this paper, the HSV-1 entry step in CD3+CD4-CD8-Jurkat T lymphocytes was investigated. Observation under electron microscopy revealed the level of filopodia formation on the surface of activated Jurkat cells was significantly higher than that of non-activated Jurkat cells especially after adding HSV-1 for 15 min. A significant increase of actin protein was demonstrated in HSV-1 infected, activated Jurkat cells compared to HSV-1 infected, non-activated Jurkat cells. After the cells were treated with 2.5 and 5 µg/mL cytochalasin D, an inhibitor of actin polymerization that causes depolymerization of actin's filamentous form, the actin protein was decreased significantly, resulting in an absence of filopodia formation. In summary, this is the first study revealing that HSV-1 induced filopodia formation through actin polymerization in activated T cells similar to epithelial, mucosal and neuronal cells. This phenomenon supported the virus entry resulting to increased yield of HSV-1 production.

Alterations in Synaptic Plasticity and Oxidative Stress Following Long-Term Paracetamol Treatment in Rat Brain.

Several studies have recently revealed that cognitive function can be affected by paracetamol (APAP) treatment. However, the exact impact of this drug treatment on learning and memory has not been clarified. This study aimed to investigate the effect of APAP treatment on the alteration of synapses and oxidative stress in the rat frontal cortex and hippocampus. APAP at a dose of 200 mg/kg bw was fed to adult male Wistar rats through either acute (n = 10), 15-day (n = 10), or 30-day (n = 10) treatment regimens. The synaptic ultrastructure and proteins, synaptophysin (SYP) and postsynaptic density-95 (PSD-95), were monitored. The amount of protein carbonyl oxidation (PCO) and glutathione (GSH) levels were examined. Our results demonstrated that acute treatment with APAP had no effect on synapses and oxidative stress. However, the synapses obtained from rats with 15-day APAP treatment showed a marked shortening of active zones and widening of the synaptic cleft. Decrement of SYP and PSD-95 proteins were demonstrated in these rats as well. With 30-day APAP treatment, the alteration of the synaptic ultrastructure and proteins was more evident. Moreover, the depletion of GSH and the elevation of PCO levels were demonstrated in the rats treated with APAP for 30 days. These results suggest that long-term APAP treatment can induce synaptic degeneration in the hippocampus and frontal cortex. The increase in oxidative stress in these brain areas may be due to the deleterious effect of this drug.

Study of Bernard-Soulier Syndrome Megakaryocytes and Platelets Using Patient-Derived Induced Pluripotent Stem Cells.

Bernard-Soulier syndrome (BSS) is a hereditary macrothrombocytopenia caused by defects in the glycoprotein (GP) Ib-IX-V complex. The mechanism of giant platelet formation remains undefined. Currently, megakaryocytes (MKs) can be generated from induced pluripotent stem cells (iPSCs) to study platelet production under pharmacological or genetic manipulations. Here, we generated iPSC lines from two BSS patients with mutations in different genes (GP1BA and GP1BB: termed BSS-A and BSS-B, respectively). The iPSC-derived MKs and platelets were examined under electron microscopy and stained by immunofluorescence to observe proplatelet formation and measure platelet diameters which were defined by circumferential tubulin. BSS-iPSCs produced abnormal proplatelets with thick shafts and tips. In addition, compared with the normal iPSCs, the diameters were larger in platelets derived from BSS-A and BSS-B with the means ± standard deviations of 4.34 ± 0.043 and 3.88 ± 0.045 µm, respectively (wild-type iPSCs 2.61 ± 0.025 µm, p < 0.001). Electron microscopy revealed giant platelets with the abnormal demarcation membrane system. Correction of BSS-A and BSS-B-iPSCs using lentiviral vectors containing respective GP1BA and GP1BB genes improved proplatelet structures and platelet ultrastructures as well as reduced platelets sizes. In conclusion, the iPSC model can be used to explore molecular mechanisms and potential therapy for BSS.

Upregulation of Pro-inflammatory Cytokine Expression Following Chronic Paracetamol Treatment in Astrocyte.

The present study aimed to investigate the effect of APAP treatment on the expression of pro-inflammatory cytokines in the astrocytes. The mouse astrocyte cells (C8-D1A) were treated with APAP at the concentration of 100 µM for 24 h, 16 and 28 days. The expressions of pro-inflammatory cytokines and NF-kB were determined using western blot analysis. Furthermore, the expression and localization of phosphorylation of NF-kB were detected by immunohistochemical and immunofluorescent analysis. The ultrastructure of C8-D1A cells was as well monitored. The results revealed that acute APAP treatment (24 h) had no effect on the expression of pro-inflammatory cytokines and pNF-kB. This treatment did not alter the ultrastructure of C8-D1A cells when compared with those in the control cells. However, the results obtained from the study on chronic APAP-treated cells (16 and 28 days) showed the different effect of APAP treatment. The results obtained from western blot analysis showed the increment of pro-inflammatory cytokine (IL-1ß and TNF-α) expressions and the activation of NF-kB signaling pathway. Nuclear translocation of pNF-kB and alteration of several cell structures were well observed in the C8-D1A cells with chronic APAP treatment. The results obtained from this study suggest that chronic APAP treatment can induce an upregulation of pro-inflammatory cytokines (IL-1ß and TNFα) in astrocytes. This alteration implies the involvement of the activation of NF-kB signaling pathway.

Up-regulation of calcitonin gene-related peptide in trigeminal ganglion following chronic exposure to paracetamol in a CSD migraine animal model.

Previously, our group has demonstrated that chronic paracetamol (APAP) treatment induces alterations to the trigeminovascular nociceptive system in the cortical spreading depression (CSD) migraine animal model. The calcitonin gene related peptide (CGRP) is a key neuropeptide involved in the activation of the trigeminovascular nociceptive system. Therefore, this study examined the expression levels of CGRP in the trigeminal ganglion (TG) after chronic APAP exposure (0, 15, and 30 days) using a CSD model. Rats were divided into control, CSD only, APAP only and APAP treatment with CSD groups. A single injection (i.p.) of APAP (200 mg/kg body weight) was given to the 0-day APAP-treated groups, while the other APAP-treated groups received daily injections for 15 and 30 days. CSD was induced by the topical application of KCl to the parietal cortex. The protein expression of CGRP in the TG was evaluated by immunohistochemistry, and the CGRP mRNA level was investigated by real-time quantitative reverse transcription polymerase chain reaction. The results revealed that the induction of CSD significantly increased the level of CGRP protein but had no effect on CGRP mRNA level. Pretreatment with APAP 1 hour before CSD activation significantly reduced CGRP expression induced by CSD. In contrast, chronic treatment with APAP (15 and 30 days) significantly enhanced CGRP expression in both protein and mRNA levels when compared with the control groups. In combination with CSD, the expression of CGRP further increased in the animal with 30 day treatment. These findings indicate that chronic treatment with APAP induces an increase of CGRP expression in the TG. This alteration may be associated with the increased trigeminovascular nociception observed in our previous studies.

Wiskott-Aldrich syndrome iPS cells produce megakaryocytes with defects in cytoskeletal rearrangement and proplatelet formation.

Wiskott-Aldrich syndrome (WAS) is an X-linked recessive disorder characterised by microthrombocytopenia, complex immunodeficiency, autoimmunity, and haematologic malignancies. It is caused by mutations in the gene encoding WAS protein (WASP), a regulator of actin cytoskeleton and chromatin structure in various blood cell lineages. The molecular mechanisms underlying microthrombocytopenia caused by WASP mutations remain elusive. Murine models of WASP deficiency exhibited only mild thrombocytopenia with normal-sized platelets. Here we report on the successful generation of induced pluripotent stem cell (iPSC) lines from two patients with different mutations in WASP (c.1507T>A and c.55C>T). When differentiated into early CD34+ haematopoietic and megakaryocyte progenitors, the WAS-iPSC lines were indistinguishable from the wild-type iPSCs. However, all WAS-iPSC lines exhibited defects in platelet productionin vitro. WAS-iPSCs produced platelets with more irregular shapes and smaller sizes. Immunofluorescence and electron micrograph showed defects in cytoskeletal rearrangement, F-actin distribution, and proplatelet formation. Proplatelet defects were more pronounced when using culture systems with stromal feeders comparing to feeder-free culture condition. Overexpression of WASP in the WAS-iPSCs using a lentiviral vector improved proplatelet structures and increased the platelet size. Our findings substantiate the use of iPSC technology to elucidate the disease mechanisms of WAS in thrombopoiesis.

Serotonin depletion can enhance the cerebrovascular responses induced by cortical spreading depression via the nitric oxide pathway.

Serotonin (5-HT) is an important neurotransmitter involved in the control of neural and vascular responses. 5-HT depletion can induce several neurological disorders, including migraines. Studies on a cortical spreading depression (CSD) migraine animal model showed that the cortical neurons sensitivity, vascular responses, and nitric oxide (NO) production were significantly increased in 5-HT depletion. However, the involvement of NO in the cerebrovascular responses in 5-HT depletion remains unclear. This study aimed to investigate the role of NO in the CSD-induced alterations of cerebral microvessels in 5-HT depletion. Rats were divided into four groups: control, control with L-NAME treatment, 5-HT depleted, and 5-HT depleted with L-NAME treatment. 5-HT depletion was induced by intraperitoneal injection with para-chlorophenylalanine (PCPA) 3 days before the experiment. The CSD was triggered by KCl application. After the second wave of CSD, N-nitro-l-arginine methyl ester (L-NAME) or saline was intravenously injected into the rats with or without L-NAME treatment groups, respectively. The intercellular adhesion molecules-1 (ICAM-1), cell adhesion molecules-1 (VCAM-1), and the ultrastructural changes of the cerebral microvessels were examined. The results showed that 5-HT depletion significantly increased ICAM-1 and VCAM-1 expressions in the cerebral cortex. The number of endothelial pinocytic vesicles and microvilli was higher in the 5-HT depleted group when compared to the control. Interestingly, L-NAME treatment significantly reduced the abnormalities observed in the 5-HT depleted group. The results of this study demonstrated that an increase of NO production is one of the mechanisms involved in the CSD-induced alterations of the cerebrovascular responses in 5-HT depletion.

Chronic paracetamol treatment increases alterations in cerebral vessels in cortical spreading depression model.

Recently, a number of non-beneficial effects of chronic treatment with paracetamol (APAP) have been reported in several systems, including circulatory system. In this study, the effects of acute (1 hour) and chronic (30 days) APAP treatments on cerebral microvessels in a cortical spreading depression (CSD) migraine animal model were investigated. Rats were divided into control, CSD only, and APAP treatment with or without CSD groups. A single dose (200 mg/kg body weight) or once-daily APAP treatment over 30 days was intraperitoneally injected into the acute and chronic APAP treated groups, respectively. CSD was induced by topical application of potassium chloride on the parietal cortex. Ultrastructural alterations and the expressions of cell adhesion molecules (ICAM-1 and VCAM-1) of the cerebral microvessels were monitored in all experimental groups. The results demonstrated that the induction of CSD caused ultrastructural alterations of the cerebral endothelial cells, as indicated by increases in microvillous and pinocytic formations and swelling of the astrocytic foot plates. The expression of ICAM-1 was significantly elevated in the CSD groups as compared with the control groups. Pretreatment with APAP 1 hour prior to CSD activation attenuated the alterations induced by CSD. However, chronic APAP treatment resulted in an enhancement of the ultrastructural alterations and the expressions of cell adhesion molecules in the cerebral microvessels that were induced by CSD. Interestingly, the rats that received chronic APAP treatment alone exhibited higher degrees of ultrastructural alterations and ICAM-1 expression than those in the control group. Based on these results, we suggest that short-term treatment with APAP has no effect on cerebral microvessels and that chronic APAP treatment can alter cerebral microvasculature, especially when combined with CSD activation.

The role of calcitonin gene-related peptide on the increase in transient receptor potential vanilloid-1 levels in trigeminal ganglion and trigeminal nucleus caudalis activation of rat.

Calcitonin gene-related peptide (CGRP) and transient receptor potential vanilloid-1 (TRPV1) play an important role in the development of pain and migraine pathogenesis. Increase in plasma CGRP levels is associated with delayed migraine-like attacks in migraine patients. Although several lines of evidence have indicated a key role of CGRP in migraine pain, its mechanisms remain unclear. In this study, we aimed to investigate the functional role of CGRP on trigeminal nociceptive pathway by determining the alteration in TRPV1 levels in trigeminal ganglion (TG) and the activation of trigeminal nucleus caudalis (TNC) of rat. Post intravenous injection of CGRP (600ng/kg) at 60min significantly increased the levels of TRPV1, CGRP, phosphorylated protein kinase C and phosphorylated cyclic AMP responsive element-binding protein in TG of rats. The number of small and medium TRPV1 and CGRP positive immunostaining neurons accompanying with co-localization of TRPV1 with CGRP neurons were significantly increased in TG of CGRP-injected rats. The sustained increase in c-Fos expression in TNC neurons was also observed in CGRP-injected rats. These results indicate that CGRP may participate in trigeminal nociceptive system sensitization by induced increase in TRPV1 and CGRP levels in TG neurons and activation of the central neurons in TNC.