Genetic polymorphisms of PRKAA1 (AMPKα1) and postherpetic pain susceptibility: Multicenter, randomized control, and haplotype analysis study.

Adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) is a pivotal regulatory protein in energy metabolism. In a pilot study, we found that AMPK-associated energy metabolism imbalance in neurons contributes to the occurrence and maintenance of neuropathic pain (NeP). This study aimed to explore the relationship between genetic polymorphisms of AMPK gene (Rs13361707, rs3792822, and rs10074991) in PRKAA1 and postherpetic neuralgia (PHN) in Chinese individuals. Hundred and thirty two patients with PHN and 118 control individuals were enrolled in this study. All blood samples were shuffled and blinded to the person performing the haplotype analysis. Rs13361707, rs3792822, and rs10074991 PRKAA1 genotypes were identified in all participants. Dominant and recessive models were used for evaluating the association between these nucleotide polymorphisms and PHN susceptibility. A haplotype analysis of PHN patients and healthy controls was performed. Clinical characteristics between the two groups were not significantly different (p > 0.05) except that the ages in control subjects were younger than the PHN patients (p < 0.05). Genotypes and allele frequencies are significantly different between the PHN patients and control subjects for the rs13361707 and rs10074991 polymorphisms (p < 0.05), but not for rs3792822 (p > 0.05). In addition, the CCG haplotype of rs13361707-rs3792822-rs10074991 correlated negatively with PHN occurrence, but TCA was positively correlated with PHN (p < 0.05). Our results indicate that PRKAA1 gene polymorphisms rs13361707 and rs10074991 were associated with a risk of PHN, and that the CCG haplotype of rs13361707-rs3792822-rs10074991 correlated negatively with PHN occurrence in haplotype analysis. TCA was positively associated with PHN in Chinese individuals.

Vagus nerve stimulation is a potential treatment for ischemic stroke.

Microglia are the brain's primary innate immune cells, and they are activated and affect pro-inflammatory phenotype or regulatory phenotype after ischemic stroke. Vagus nerve stimulation was shown to activate microglial phenotypic changes and exhibit neuroprotective effects in ischemia/reperfusion injury. In this study, we established rat models of ischemic stroke by occlusion of the middle cerebral artery and performed vagus nerve stimulation 30 minutes after modeling. We found that vagus nerve stimulation caused a shift from a pro-inflammatory phenotype to a regulatory phenotype in microglia in the ischemic penumbra. Vagus nerve stimulation decreased the levels of pro-inflammatory phenotype markers inducible nitric oxide synthase and tumor necrosis factor α and increased the expression of regulatory phenotype markers arginase 1 and transforming growth factor ß through activating α7 nicotinic acetylcholine receptor expression. Additionally, α7 nicotinic acetylcholine receptor blockade reduced the inhibition of Toll-like receptor 4/nuclear factor kappa-B pathway-associated proteins, including Toll-like receptor 4, myeloid differentiation factor 88, I kappa B alpha, and phosphorylated-I kappa B alpha, and also weakened the neuroprotective effects of vagus nerve stimulation in ischemic stroke. Vagus nerve stimulation inhibited Toll-like receptor 4/nuclear factor kappa-B expression through activating α7 nicotinic acetylcholine receptor and regulated microglial polarization after ischemic stroke, thereby playing a role in the treatment of ischemic stroke. Findings from this study confirm the mechanism underlying vagus nerve stimulation against ischemic stroke.

Effect of AMPK Subunit Alpha 2 Polymorphisms on Postherpetic Pain Susceptibility in Southwestern Han Chinese.

Introduction: Adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) can influence energy metabolism. Energy metabolism imbalance is closely associated with the occurrence of neuropathic pain (NeP). Rs10789038 and rs2796498 are genetic polymorphisms of PRKAA2, the gene encoding AMPK, which is closely related to energy metabolism imbalance. This study aimed to explore the relationship between PRKAA2 and postherpetic neuralgia (PHN) in the southwestern Chinese Han population. Methods: This study enrolled 132 PHN patients and 118 healthy subjects. The rs10789038 and rs2796498 PRKAA2 genotypes were identified in all participants. The association between these single nucleotide polymorphisms and PHN susceptibility was evaluated in the dominant and recessive models. Haplotype analysis of patients with PHN and healthy controls was performed. Results: The PHN patients were older than the healthy subjects (P < 0.05); however, the other clinical characteristics between two groups were not significantly different (all P >0.05). Genotypes and allele frequencies differed significantly between PHN patients and healthy subjects in the rs10789038 polymorphism (P < 0.05), but not in rs2796498 (P > 0.05). In addition, the GG haplotype of rs10789038-rs2796498 correlated negatively with PHN occurrence in haplotype analysis (P < 0.05). Conclusion: PHN occurrence may be related to the PRKAA2 rs10789038 A>G genetic polymorphism in the southwestern Chinese Han population.

Chemogenetic activation of glutamatergic neurons in the motor cortex promotes functional recovery after ischemic stroke in rats.

Ischemic stroke is a major cause of disability and mortality worldwide, while no unequivocally efficacious drug is currently available to treat post-stroke functional impairments. Animal and clinical investigations suggest that the motor cortex stimulation constitutes a particularly promising approach for promoting function recovery after stroke. However, the cell types and mechanisms involved in stimulation-induced recovery are not well understood. Here, we used chemogenetic technique to selectively activate glutamatergic neurons in the primary motor cortex and investigated whether activation of glutamatergic neurons in the primary motor cortex can promote functional recovery after ischemic stroke in rats. The results showed that chemogenetic activation of the motor cortex glutamatergic neurons significantly decreased the neurological deficit scores, as well as significantly increased the grip test scores and the hanging time. Moreover, the glutamatergic neuronal activation also significantly decreased the escape latencies, increased the swimming speed, target quadrant time, and numbers of crossing platform position in the Morris water maze test. These results demonstrate that selective activation of the glutamatergic neurons in primary motor cortex is sufficient to promote functional recovery after ischemic stroke, and may be of importance in understanding the neural cellular mechanisms underlying the motor cortex stimulation-induced functional recovery.

Inhibition of breast cancer cell growth by methyl pyropheophenylchlorin photodynamic therapy is mediated though endoplasmic reticulum stress-induced autophagy in vitro and vivo.

Autophagy and ER stress participated in the inhibition of MPPa-PDT on tumor growth, but the molecular links between them remain undefined. We just explore the molecular mechanism between them in vitro and vivo. CCK-8 assay and flow cytometer were used to detect the cytotoxicity and mode of cell death after MPPa-PDT. Furthermore, the role of autophagy was verified in MPPa-PDT. Confocal microscopy was used to show the intracellular distribution of MPPa. ER stress markers and PERK signaling pathway were detected by western blot. While in vivo, tumor histology and immunohistochemistry were performed to show the effect of MPPa-PDT in mice. After MPPa-PDT, cells viability decreased in dose-dependent manner. Besides, the cell apoptosis increased along with the increasing of Beclin-1and LC3B II but declining of P62. When pretreated with 3-MA, LC3B II formation and the cytotoxicity declined. MPPa-PDT caused increasing of ER stress markers (GRP78, CHOP) as MPPa accumulated in ER. However, pretreatment with ER stress inhibitor 4PBA, the expression of GRP78 and LC3B II was blocked but the PERK signaling pathway activated and the expression of P62 increased. In vivo, the tumor growth was significantly inhibited by MPPa-PDT. Besides, the appearance of ER stress and autophagy was further demonstrated by immunohistochemistry. Our findings demonstrate that autophagy mediated by MPPa-PDT was regulated by ER stress, via PERK signaling pathway, to kill MDA-MB-231 cells in vitro and vivo.

Local injection of Lenti-Olig2 at lesion site promotes functional recovery of spinal cord injury in rats.

AIMS: Olig2 is one of the most critical factors during CNS development, which belongs to b-HLH transcription factor family. Previous reports have shown that Olig2 regulates the remyelination processes in CNS demyelination diseases models. However, the role of Olig2 in contusion spinal cord injury (SCI) and the possible therapeutic effects remain obscure. This study aims to investigate the effects of overexpression Olig2 by lentivirus on adult spinal cord injury rats. METHODS: Lenti-Olig2 expression and control Lenti-eGFP vectors were prepared, and virus in a total of 5 µL (108 TU/mL) was locally injected into the injured spinal cord 1.5 mm rostral and caudal near the epicenter. Immunostaining, Western blot, electron microscopy, and CatWalk analyzes were employed to investigate the effects of Olig2 on spinal cord tissue repair and functional recovery. RESULTS: Injection of Lenti-Olig2 significantly increased the number of oligodendrocytes lineage cells and enhanced myelination after SCI. More importantly, the introduction of Olig2 greatly improved hindlimb locomotor performances. Other oligodendrocyte-related transcription factors, which were downregulated or upregulated after injury, were reversed by Olig2 induction. CONCLUSIONS: Our findings provided the evidence that overexpression Olig2 promotes myelination and locomotor recovery of contusion SCI, which gives us more understanding of Olig2 on spinal cord injury treatment.

Enhancement of the Effect of Methyl Pyropheophorbide-a-Mediated Photodynamic Therapy was Achieved by Increasing ROS through Inhibition of Nrf2-HO-1 or Nrf2-ABCG2 Signaling.

BACKGROUND: Emerging evidence indicates that the transcription factor nuclear factor-E2-related factor 2 (Nrf2) plays an essential role in cellular defense against oxidative stress; its activation has been related to cytoprotection. OBJECTIVE: Here, we investigated the role of Nrf2 in improving the efficacy of methyl pyropheophorbide-amediated photodynamic therapy (Mppa-PDT) via the downregulation of Nrf2. METHOD: Human ovarian cancer A2780 cells and SKOV3 cells were treated with Mppa-PDT and siRNA transfection was performed to inhibit Nrf2. After treated with siRNA and Mppa-PDT, the cell viability was examined with CCK-8 assay; cell apoptosis was detected tested by flow cytometry with Annexin V-FITC/PI; the celluar reactive oxygen species (ROS) and mitochondrial membrane potential were measured with DCFHDA and JC-1 staining; expression of protein was assessed by western blot analysis. RESULTS: We found that Nrf2 translocated from the cytoplasm to the nucleus in vitro and in vivo, and the expression of Nrf2 and P-Nrf2 increased through a possible mechanism regulated by mitogen-activated protein kinase (MAPK) after Mppa-PDT treatment. Furthermore, cytotoxicity and apoptosis induced by Mppa-PDT increased after Nrf2down-regulation. Nrf2 down -regulation increased reactive oxygen species (ROS) levels by attenuating antioxidants or pumping Mppa out of cells,which resulted from the inhibition of Nrf2-HO-1 or Nrf2- ABCG2 signaling. In addition, SKOV3 cells exhibited increased resistance to Mppa-PDT, and the expression levels of P-Nrf2 and ABCG2 were higher in SKOV3 cells than in A2780 cells, suggesting that Nrf2-ABCG2 signaling might be involved in the intrinsic resistanceto Mppa-PDT. CONCLUSION: These results provided evidence that Nrf2 down-regulation can enhance the effect of Mppa-PDT.

Preventive treatment of astaxanthin provides neuroprotection through suppression of reactive oxygen species and activation of antioxidant defense pathway after stroke in rats.

Astaxanthin, a natural antioxidant carotenoid, has been shown to reduce cerebral ischemic injury in rodents. However, there have not been any studies specifically addressing whether preventive administration of astaxanthin can protect against cerebral ischemia. The purpose of this study was to examine whether pretreatment of astaxanthin can protect against ischemic injuries in the adult rats. The rats were pre-administered intragastrically with astaxanthin for seven days (once a day), and middle cerebral artery occlusion was performed at 1h after the final administration. It was found that astaxanthin prevented neurological deficits and reduced cerebral infarction volume. To evaluate the mechanisms underlying this protection, brain tissues were assayed for free radical damage, antioxidant gene expression, cell apoptosis and regeneration. The results showed that the mechanisms involved suppression of reactive oxygen species, activation of antioxidant defense pathway, and inhibition of apoptosis as well as promotion of neural regeneration. Astaxanthin did not alter body weights and the protective effect was found to be dose-dependent. Collectively, our data suggest that pretreatment of astaxanthin can protect against ischemia-related damages in brain tissue through multiple mechanisms, hinting that astaxanthin may have significant protective effects for patients vulnerable or prone to ischemic events.

Exploring a Novel Target Treatment on Breast Cancer: Aloe-emodin Mediated Photodynamic Therapy Induced Cell Apoptosis and Inhibited Cell Metastasis.

Photodynamic therapy (PDT) as a clinical cancer therapy, is a mild therapy, which involves application of photosensitizers (PSs) located in target cells and then irradiated by corresponding wavelength. The activation of PSs generates radical oxygen species (ROS) to exert a selective cytotoxic activity for the target cells. Aloe-emodin (AE) has been found to be an anti-tumor agent in many studies, and has also been demonstrated as a photosensitizer, in the recent years. In order to study the mechanisms of aloe-emodin as a photosensitizer, we investigated the mechanisms of photo-cytotoxicity induced by aloe-emodin in breast cancer MCF-7 cells in the present study. Analysis of cell proliferation evidenced that there was a drastic depression after photodynamic treatment with a series of aloe-emodin concentrations and light doses. We observed changes in apoptosis and demonstrated that the mechanisms of apoptosis were involved in mitochondrial and endoplasmic reticulum death pathways. The capacity of adhesion, migration and invasion of breast cells was measured using WST8 and transwell assay and demonstrated that AE-PDT significantly inhibited adhesion, migration and invasion of MCF-7cells. The expression of MMP2, MMP9, VEGF and Nrf2 demonstrated that the metastasis was related to oxidative stress. Analysis of changes in cytoskeleton components (F-actin) evidenced cytoskeleton disorganization after treatment with AE-PDT. Taken together, the present results indicated that PDT with aloe-emodin effectively suppressed cancer development in MCF-7cells, suggesting the potential of AE as a new photosensitizer in PDT which can provide a new modility for treating cancer.