Microbiota regulate social behaviour via stress response neurons in the brain.

Social interactions among animals mediate essential behaviours, including mating, nurturing, and defence1,2. The gut microbiota contribute to social activity in mice3,4, but the gut-brain connections that regulate this complex behaviour and its underlying neural basis are unclear5,6. Here we show that the microbiome modulates neuronal activity in specific brain regions of male mice to regulate canonical stress responses and social behaviours. Social deviation in germ-free and antibiotic-treated mice is associated with elevated levels of the stress hormone corticosterone, which is primarily produced by activation of the hypothalamus-pituitary-adrenal (HPA) axis. Adrenalectomy, antagonism of glucocorticoid receptors, or pharmacological inhibition of corticosterone synthesis effectively corrects social deficits following microbiome depletion. Genetic ablation of glucocorticoid receptors in specific brain regions or chemogenetic inactivation of neurons in the paraventricular nucleus of the hypothalamus that produce corticotrophin-releasing hormone (CRH) reverse social impairments in antibiotic-treated mice. Conversely, specific activation of CRH-expressing neurons in the paraventricular nucleus induces social deficits in mice with a normal microbiome. Via microbiome profiling and in vivo selection, we identify a bacterial species, Enterococcus faecalis, that promotes social activity and reduces corticosterone levels in mice following social stress. These studies suggest that specific gut bacteria can restrain the activation of the HPA axis, and show that the microbiome can affect social behaviours through discrete neuronal circuits that mediate stress responses in the brain.

Secondary structure of the human mitochondrial genome affects formation of deletions.

BACKGROUND: Aging in postmitotic tissues is associated with clonal expansion of somatic mitochondrial deletions, the origin of which is not well understood. Such deletions are often flanked by direct nucleotide repeats, but this alone does not fully explain their distribution. Here, we hypothesized that the close proximity of direct repeats on single-stranded mitochondrial DNA (mtDNA) might play a role in the formation of deletions. RESULTS: By analyzing human mtDNA deletions in the major arc of mtDNA, which is single-stranded during replication and is characterized by a high number of deletions, we found a non-uniform distribution with a "hot spot" where one deletion breakpoint occurred within the region of 6-9 kb and another within 13-16 kb of the mtDNA. This distribution was not explained by the presence of direct repeats, suggesting that other factors, such as the spatial proximity of these two regions, can be the cause. In silico analyses revealed that the single-stranded major arc may be organized as a large-scale hairpin-like loop with a center close to 11 kb and contacting regions between 6-9 kb and 13-16 kb, which would explain the high deletion activity in this contact zone. The direct repeats located within the contact zone, such as the well-known common repeat with a first arm at 8470-8482 bp (base pair) and a second arm at 13,447-13,459 bp, are three times more likely to cause deletions compared to direct repeats located outside of the contact zone. A comparison of age- and disease-associated deletions demonstrated that the contact zone plays a crucial role in explaining the age-associated deletions, emphasizing its importance in the rate of healthy aging. CONCLUSIONS: Overall, we provide topological insights into the mechanism of age-associated deletion formation in human mtDNA, which could be used to predict somatic deletion burden and maximum lifespan in different human haplogroups and mammalian species.

Chaperonin counteracts diet-induced non-alcoholic fatty liver disease by aiding sirtuin 3 in the control of fatty acid oxidation.

AIMS/HYPOTHESIS: The mitochondrial chaperonin heat shock protein (HSP) 60 is indispensable in protein folding and the mitochondrial stress response; however, its role in nutrient metabolism remains uncertain. This study investigated the role of HSP60 in diet-induced non-alcoholic fatty liver disease (NAFLD). METHODS: We studied human biopsies from individuals with NAFLD, murine high-fat-diet (HFD; a diet with 60% energy from fat)-induced obesity (DIO), transgenic (Tg) mice overexpressing Hsp60 (Hsp60-Tg), and human HepG2 cells transfected with HSP60 cDNA or with HSP60 siRNA. Histomorphometry was used to assess hepatic steatosis, biochemistry kits were used to measure insulin resistance and glucose tolerance, and an automated home cage phenotyping system was used to assess energy expenditure. Body fat was assessed using MRI. Macrophage infiltration, the lipid oxidation marker 4-hydroxy-2-nonenal (4-HNE) and the oxidative damage marker 8-hydroxy-2'-deoxyguanosine (8-OHdG) were detected using immunohistochemistry. Intracellular lipid droplets were evaluated by Nile red staining. Expression of HSP60, and markers of lipogenesis and fatty acid oxidation were quantified using RT-PCR and immunoblotting. Investigations were analysed using the two-way ANOVA test. RESULTS: Decreased HSP60 expression correlated with severe steatosis in human NAFLD biopsies and murine DIO. Hsp60-Tg mice developed less body fat, had reduced serum triglyceride levels, lower levels of insulin resistance and higher serum adiponectin levels than wild-type mice upon HFD feeding. Respiratory quotient profile indicated that fat in Hsp60-Tg mice may be metabolised to meet energy demands. Hsp60-Tg mice showed amelioration of HFD-mediated hepatic steatosis, M1/M2 macrophage dysregulation, and 4-HNE and 8-OHdG overproduction. Forced HSP60 expression reduced the mitochondrial unfolded protein response, while preserving mitochondrial respiratory complex activity and enhancing fatty acid oxidation. Furthermore, HSP60 knockdown enhanced intracellular lipid formation and loss of sirtuin 3 (SIRT3) signalling in HepG2 cells upon incubation with palmitic acid (PA). Forced HSP60 expression improved SIRT3 signalling and repressed PA-mediated intracellular lipid formation. SIRT3 inhibition compromised HSP60-induced promotion of AMP-activated protein kinase (AMPK) phosphorylation and peroxisome proliferator-activated receptor α (PPARα levels), while also decreasing levels of fatty acid oxidation markers. CONCLUSION/INTERPRETATION: Mitochondrial HSP60 promotes fatty acid oxidation while repressing mitochondrial stress and inflammation to ameliorate the development of NAFLD by preserving SIRT3 signalling. This study reveals the hepatoprotective effects of HSP60 and indicates that HSP60 could play a fundamental role in the development of therapeutics for NAFLD or type 2 diabetes.

Impact of the m.13513G>A Variant on the Functions of the OXPHOS System and Cell Retrograde Signaling.

Mitochondria are involved in many vital functions in living cells, including the synthesis of ATP by oxidative phosphorylation (OXPHOS) and regulation of nuclear gene expression through retrograde signaling. Leigh syndrome is a heterogeneous neurological disorder resulting from an isolated complex I deficiency that causes damage to mitochondrial energy production. The pathogenic mitochondrial DNA (mtDNA) variant m.13513G>A has been associated with Leigh syndrome. The present study investigated the effects of this mtDNA variant on the OXPHOS system and cell retrograde signaling. Transmitochondrial cytoplasmic hybrid (cybrid) cell lines harboring 50% and 70% of the m.13513G>A variant were generated and tested along with wild-type (WT) cells. The functionality of the OXPHOS system was evaluated by spectrophotometric assessment of enzyme activity and high-resolution respirometry. Nuclear gene expression was investigated by RNA sequencing and droplet digital PCR. Increasing levels of heteroplasmy were associated with reduced OXPHOS system complex I, IV, and I + III activities, and high-resolution respirometry also showed a complex I defect. Profound changes in transcription levels of nuclear genes were observed in the cell lines harboring the pathogenic mtDNA variant, indicating the physiological processes associated with defective mitochondria.

Butterflies in the gut: the interplay between intestinal microbiota and stress.

Psychological stress is a global issue that affects at least one-third of the population worldwide and increases the risk of numerous psychiatric disorders. Accumulating evidence suggests that the gut and its inhabiting microbes may regulate stress and stress-associated behavioral abnormalities. Hence, the objective of this review is to explore the causal relationships between the gut microbiota, stress, and behavior. Dysbiosis of the microbiome after stress exposure indicated microbial adaption to stressors. Strikingly, the hyperactivated stress signaling found in microbiota-deficient rodents can be normalized by microbiota-based treatments, suggesting that gut microbiota can actively modify the stress response. Microbiota can regulate stress response via intestinal glucocorticoids or autonomic nervous system. Several studies suggest that gut bacteria are involved in the direct modulation of steroid synthesis and metabolism. This review provides recent discoveries on the pathways by which gut microbes affect stress signaling and brain circuits and ultimately impact the host's complex behavior.

Microbial metabolites regulate social novelty via CaMKII neurons in the BNST.

Social novelty is a cognitive process that is essential for animals to interact strategically with conspecifics based on their prior experiences. The commensal microbiome in the gut modulates social behavior through various routes, including microbe-derived metabolite signaling. Short-chain fatty acids (SCFAs), metabolites derived from bacterial fermentation in the gastrointestinal tract, have been previously shown to impact host behavior. Herein, we demonstrate that the delivery of SCFAs directly into the brain disrupts social novelty through distinct neuronal populations. We are the first to observe that infusion of SCFAs into the lateral ventricle disrupted social novelty in microbiome-depleted mice without affecting brain inflammatory responses. The deficit in social novelty can be recapitulated by activating calcium/calmodulin-dependent protein kinase II (CaMKII)-labeled neurons in the bed nucleus of the stria terminalis (BNST). Conversely, chemogenetic silencing of the CaMKII-labeled neurons and pharmacological inhibition of fatty acid oxidation in the BNST reversed the SCFAs-induced deficit in social novelty. Our findings suggest that microbial metabolites impact social novelty through a distinct neuron population in the BNST.

Dabigatran or Aspirin in East Asian Patients With Embolic Stroke of Undetermined Source: RE-SPECT ESUS Subgroup Analysis.

BACKGROUND AND PURPOSE: We assessed the outcomes of dabigatran versus aspirin in a prespecified subgroup analysis of East Asian patients with embolic stroke of undetermined source in the RE-SPECT ESUS trial (Randomized, Double-Blind, Evaluation in Secondary Stroke Prevention Comparing the Efficacy and Safety of the Oral Thrombin Inhibitor Dabigatran Etexilate Versus Acetylsalicylic Acid in Patients With Embolic Stroke of Undetermined Source). METHODS: Patients with a recent embolic stroke of undetermined source were randomized to dabigatran (150 or 110 mg BID) or aspirin (100 mg QD). The primary efficacy outcome was recurrent stroke; the primary safety outcome was major bleeding. The East Asia cohort was compared with patients from all other countries (non-East Asia cohort). RESULTS: Overall, 988 of 5390 patients (18%) were randomized in East Asia. During a median follow-up of 18.8 months, there was no statistically significant difference in recurrent stroke (hazard ratio, 0.65 [95% CI, 0.41-1.03]) or major bleeding (hazard ratio, 1.04 [95% CI, 0.57-1.91]) in East Asian patients receiving dabigatran versus aspirin. Death from any cause occurred more often in the dabigatran versus the aspirin group (hazard ratio, 3.98 [95% CI, 1.32-12.01]). CONCLUSIONS: The treatment effect of dabigatran versus aspirin was consistent between cohorts, with no apparent superiority for dabigatran over aspirin in preventing recurrent stroke in patients with embolic stroke of undetermined source. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02239120.

miR-21-5p Under-Expression in Patients with Obstructive Sleep Apnea Modulates Intermittent Hypoxia with Re-Oxygenation-Induced-Cell Apoptosis and Cytotoxicity by Targeting Pro-Inflammatory TNF-α-TLR4 Signaling.

The purpose of this study is to explore the anti-inflammatory role of microRNAs (miR)-21 and miR-23 targeting the TLR/TNF-α pathway in response to chronic intermittent hypoxia with re-oxygenation (IHR) injury in patients with obstructive sleep apnea (OSA). Gene expression levels of the miR-21/23a, and their predicted target genes were assessed in peripheral blood mononuclear cells from 40 treatment-naive severe OSA patients, and 20 matched subjects with primary snoring (PS). Human monocytic THP-1 cell lines were induced to undergo apoptosis under IHR exposures, and transfected with miR-21-5p mimic. Both miR-21-5p and miR-23-3p gene expressions were decreased in OSA patients as compared with that in PS subjects, while TNF-α gene expression was increased. Both miR-21-5p and miR-23-3p gene expressions were negatively correlated with apnea hypopnea index and oxygen desaturation index, while TNF-α gene expression positively correlated with apnea hypopnea index. In vitro IHR treatment resulted in decreased miR-21-5p and miR-23-3p expressions. Apoptosis, cytotoxicity, and gene expressions of their predicted target genes-including TNF-α, ELF2, NFAT5, HIF-2α, IL6, IL6R, EDNRB, and TLR4-were all increased in response to IHR, while all were reversed with miR-21-5p mimic transfection under IHR condition. The findings provide biological insight into mechanisms by which IHR-suppressed miRs protect cell apoptosis via inhibit inflammation, and indicate that over-expression of the miR-21-5p may be a new therapy for OSA.

Peroxisome Proliferator-Activated Receptor γ Coactivator 1α Activates Vascular Endothelial Growth Factor That Protects Against Neuronal Cell Death Following Status Epilepticus through PI3K/AKT and MEK/ERK Signaling.

Status epilepticus may cause molecular and cellular events, leading to hippocampal neuronal cell death. Peroxisome proliferator-activated receptor γ coactivator 1-α (PGC-1α) is an important regulator of vascular endothelial growth factor (VEGF) and VEGF receptor 2 (VEGFR2), also known as fetal liver kinase receptor 1 (Flk-1). Resveratrol is an activator of PGC-1α. It has been suggested to provide neuroprotective effects in epilepsy, stroke, and neurodegenerative diseases. In the present study, we used microinjection of kainic acid into the left hippocampal CA3 region in Sprague Dawley rats to induce bilateral prolonged seizure activity. Upregulating the PGC-1α pathway will increase VEGF/VEGFR2 (Flk-1) signaling and further activate some survival signaling that includes the mitogen activated protein kinase kinase (MEK)/mitogen activated protein kinase (ERK) and phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling pathways and offer neuroprotection as a consequence of apoptosis in the hippocampal neurons following status epilepticus. Otherwise, downregulation of PGC-1α by siRNA against pgc-1α will inhibit VEGF/VEGFR2 (Flk-1) signaling and suppress pro-survival PI3K/AKT and MEK/ERK pathways that are also accompanied by hippocampal CA3 neuronal cell apoptosis. These results may indicate that the PGC-1α induced VEGF/VEGFR2 pathway may trigger the neuronal survival signaling, and the PI3K/AKT and MEK/ERK signaling pathways. Thus, the axis of PGC-1α/VEGF/VEGFR2 (Flk-1) and the triggering of downstream PI3K/AKT and MEK/ERK signaling could be considered an endogenous neuroprotective effect against apoptosis in the hippocampus following status epilepticus.

The Overcrowded Crossroads: Mitochondria, Alpha-Synuclein, and the Endo-Lysosomal System Interaction in Parkinson's Disease.

Parkinson's disease (PD) is the second most common neurodegenerative disorder worldwide, mainly affecting the elderly. The disease progresses gradually, with core motor presentations and a multitude of non-motor manifestations. There are two neuropathological hallmarks of PD, the dopaminergic neuronal loss and the alpha-synuclein-containing Lewy body inclusions in the substantia nigra. While the exact pathomechanisms of PD remain unclear, genetic investigations have revealed evidence of the involvement of mitochondrial function, alpha-synuclein (α-syn) aggregation, and the endo-lysosomal system, in disease pathogenesis. Due to the high energy demand of dopaminergic neurons, mitochondria are of special importance acting as the cellular powerhouse. Mitochondrial dynamic fusion and fission, and autophagy quality control keep the mitochondrial network in a healthy state. Should defects of the organelle occur, a variety of reactions would ensue at the cellular level, including disrupted mitochondrial respiratory network and perturbed calcium homeostasis, possibly resulting in cellular death. Meanwhile, α-syn is a presynaptic protein that helps regulate synaptic vesicle transportation and endocytosis. Its misfolding into oligomeric sheets and fibrillation is toxic to the mitochondria and neurons. Increased cellular oxidative stress leads to α-syn accumulation, causing mitochondrial dysfunction. The proteasome and endo-lysosomal systems function to regulate damage and unwanted waste management within the cell while facilitating the quality control of mitochondria and α-syn. This review will analyze the biological functions and interactions between mitochondria, α-syn, and the endo-lysosomal system in the pathogenesis of PD.

2017 Taiwan lipid guidelines for high risk patients.

In Taiwan, the prevalence of hyperlipidemia increased due to lifestyle and dietary habit changes. Low density lipoprotein cholesterol (LDL-C) and non-high density lipoprotein cholesterol (non-HDL-C) are all significant predicting factors of coronary artery disease in Taiwan. We recognized that lipid control is especially important in patients with existed atherosclerotic cardiovascular diseases (ASCVD), including coronary artery disease (CAD), ischemic stroke and peripheral arterial disease (PAD). Because the risk of ASCVD is high in patients with diabetes mellitus (DM), chronic kidney disease (CKD) and familial hypercholesterolemia (FH), lipid control is also necessary in these patients. Lifestyle modification is the first step to control lipid. Weight reduction, regular physical exercise and limitation of alcohol intake all reduce triglyceride (TG) levels. Lipid-lowering drugs include HMG-CoA reductase inhibitors (statins), cholesterol absorption inhibitors (ezetimibe), proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, nicotinic acids (niacin), fibric acids derivatives (fibrates), and long-chain omega-3 fatty acids. Statin is usually the first line therapy. Combination therapy with statin and other lipid-lowering agents may be considered in some clinical settings. For patients with acute coronary syndrome (ACS) and stable CAD, LDL-C < 70 mg/dL is the major target. A lower target of LDL-C <55 mg/dL can be considered in ACS patients with DM. After treating LDL-C to target, non-HDL-C can be considered as a secondary target for patients with TG ≥ 200 mg/dL. The suggested non-HDL-C target is < 100 mg/dL in ACS and CAD patients. For patients with ischemic stroke or transient ischemic attack presumed to be of atherosclerotic origin, statin therapy is beneficial and LDL-C < 100 mg/dL is the suggested target. For patients with symptomatic carotid stenosis or intracranial arterial stenosis, in addition to antiplatelets and blood pressure control, LDL-C should be lowered to < 100 mg/dL. Statin is necessary for DM patients with CV disease and the LDL-C target is < 70 mg/dL. For diabetic patients who are ≥ 40 years of age, or who are < 40 years of age but have additional CV risk factors, the LDL-C target should be < 100 mg/dL. After achieving LDL-C target, combination of other lipid-lowering agents with statin is reasonable to attain TG < 150 mg/dL and HDL-C >40 in men and >50 mg/dL in women in DM. LDL-C increased CV risk in patients with CKD. In adults with glomerular filtration rate (GFR) < 60 mL/min/1.73m2 without chronic dialysis (CKD stage 3-5), statin therapy should be initiated if LDL-C ≥ 100 mg/dL. Ezetimibe can be added to statin to consolidate the CV protection in CKD patients. Mutations in LDL receptor, apolipoprotein B and PCSK9 genes are the common causes of FH. Diagnosis of FH usually depends on family history, clinical history of premature CAD, physical findings of xanthoma or corneal arcus and high levels of LDL-C. In addition to conventional lipid lowering therapies, adjunctive treatment with mipomersen, lomitapide, or PCSK9 inhibitors become necessary to further reduce LDL-C in patients with FH. Overall, these recommendations are to help the health care professionals in Taiwan to treat hyperlipidemia with current scientific evidences. We hope the prescription rate of lipid lowering drugs and control rate of hyperlipidemia in high risk patients could be increased by implementation of the clinical guidelines. The major purpose is to improve clinical outcomes of these high risk patients through the control of hyperlipidemia.

mtDNA as a Mediator for Expression of Hypoxia-Inducible Factor 1α and ROS in Hypoxic Neuroblastoma Cells.

Mitochondria consume O2 to produce ATP and are critical for adaption of hypoxia, but the role of mitochondria in HIF-1α pathway is as yet unclear. In this study, mitochondrial DNA (mtDNA) enriched (SK-N-AS) and depleted (ρ°) cells of neuroblastoma were cultured in a hypoxic chamber to simulate a hypoxic condition and then the major components involved in mitochondrial related pathways, hypoxia-inducible factor 1α (HIF-1α) and reactive oxygen species (ROS) were measured. The results showed that hypoxia-stimulated exposure elevated expression of HIF-1α, which was additionally influenced by level of generated ROS within the cytosol. Moreover, elevation of HIF-1α also resulted in increases of lactate dehydrogenase A (LDH-A) and pyruvate dehydrogenase kinase 1 (PDK1) in both hypoxic cells. The expression of mitochondrial biogenesis related proteins and metabolic components were noted to increase significantly in hypoxic SK-N-AS cells, indicating that mtDNA was involved in mitochondrial retrograde signaling and metabolic pathways. An analysis of dynamic proteins found elevated levels of HIF-1α causing an increased expression of dynamin-related protein 1 (DRP1) during hypoxia; further, the existence of mtDNA also resulted in higher expression of DRP1 during hypoxia. By using siRNA of HIF-1α or DRP1, expression of DRP1 decreased after suppression of HIF-1α; moreover, the expression of HIF-1α was also affected by the suppression of DRP1. In this study, we demonstrated that mtDNA is a mediator of HIF-1α in eliciting metabolic reprogramming, and mitochondrial biogenesis. Identification of a mutual relationship between HIF-1α and DRP1 may be a critical tool in the future development of clinical applications.

Peroxisome proliferator-activated receptor-gamma dependent pathway reduces the phosphorylation of dynamin-related protein 1 and ameliorates hippocampal injury induced by global ischemia in rats.

BACKGROUND: Dynamin-related protein 1 (Drp1) is a mitochondrial fission protein that, upon phosphorylation at serine 616 (p-Drp1(Ser616)), plays a pivotal role in neuronal death after ischemia. In the present study, we hypothesized that peroxisome proliferator-activated receptor-gamma (PPARγ)-dependent pathway can reduce the expression of p-Drp1(Ser616) and ameliorate hippocampal injury induced by global ischemia in rats. RESULTS: We found that pretreatment of the rats with Mdivi-1, a selective Drp1 inhibitor, decreased the level of transient global ischemia (TGI)-induced p-Drp1(Ser616) and reduced cellular contents of oxidized proteins, activated caspase-3 expression as well as the extent of DNA fragmentation. Delivery of siRNA against Drp1 attenuated the expression of p-Drp1(Ser616) that was accompanied by alleviation of the TGI-induced protein oxidation, activated caspase-3 expression and DNA fragmentation in hippocampal proteins. Exogenous application of pioglitazone, a PPARγ agonist, reduced the p-Drp1(Ser616) expression, decreased TGI-induced oxidative stress and activated caspase-3 expression, lessened the extents of DNA fragmentation, and diminished the numbers of TUNEL-positive neuronal cells; all of these effects were reversed by GW9662, a PPARγ antagonist. CONCLUSIONS: Our findings thus indicated that inhibition of TGI-induced p-Drp1(Ser616) expression by Drp1 inhibitor and Drp1-siRNA can decrease protein oxidation, activated caspase-3 expression and neuronal damage in the hippocampal CA1 subfield. PPARγ agonist, through PPARγ-dependent mechanism and via decreasing p-Drp1(Ser616) expression, can exert anti-oxidative and anti-apoptotic effects against ischemic neuronal injury.

Associations of mitochondrial haplogroups b4 and e with biliary atresia and differential susceptibility to hydrophobic bile Acid.

Mitochondrial dysfunction has been implicated in the pathogenesis of biliary atresia (BA). This study aimed to determine whether a specific mitochondrial DNA haplogroup is implicated in the pathogenesis and prognosis of BA. We determined 40 mitochondrial single nucleotide polymorphisms in 15 major mitochondrial haplogroups by the use of 24-plex PCR and fluorescent beads combined with sequence-specific oligonucleotide probes in 71 patients with BA and in 200 controls in the Taiwanese population of ethnic Chinese background. The haplogroup B4 and E prevalence were significantly lower and higher respectively, in the patients with BA than in the controls (odds ratios, 0.82 [p = 0.007] and 7.36 [p = 0.032] respectively) in multivariate logistic-regression analysis. The 3-year survival rate with native liver was significantly lower in haplogroup E than the other haplogroups (P = 0.037). A cytoplasmic hybrid (cybrid) was obtained from human 143B osteosarcoma cells devoid of mtDNA (ρ(0) cell) and was fused with specific mtDNA bearing E and B4 haplogroups donated by healthy Taiwanese subjects. Chenodeoxycholic acid treatment resulted in significantly lower free radical production, higher mitochondrial membrane potential, more viable cells, and fewer apoptotic cybrid B4 cells than parental 143B and cybrid E cells. Bile acid treatment resulted in a significantly greater protective mitochondrial reaction with significantly higher mitochondrial DNA copy number and mitofusin 1 and 2 concentrations in cybrid B4 and parental cells than in cybrid E cells. The results of the study suggested that the specific mitochondrial DNA haplogroups B4 and E were not only associated with lower and higher prevalence of BA respectively, in the study population, but also with differential susceptibility to hydrophobic bile acid in the cybrid harboring different haplogroups.

Roles of PTEN-induced putative kinase 1 and dynamin-related protein 1 in transient global ischemia-induced hippocampal neuronal injury.

Recent studies showed that increased mitochondrial fission is an early event of cell death during cerebral ischemia and dynamin-related protein 1 (Drp1) plays an important role in mitochondrial fission, which may be regulated by PTEN-induced putative kinase 1 (PINK1), a mitochondrial serine/threonine-protein kinase thought to protect cells from stress-induced mitochondrial dysfunction and regulate mitochondrial fission. However, the roles of PINK1 and Drp1 in hippocampal injury caused by transient global ischemia (TGI) remain unknown. We therefore tested the hypothesis that TGI may induce PINK1 causing downregulation of Drp1 phosphorylation to enhance hippocampal neuronal survival, thus functioning as an endogenous neuroprotective mechanism. We found progressively increased PINK1 expression in the hippocampal CA1 subfield1-48 h following TGI, reaching the maximal level at 4 h. Despite lack of changes in the expression level of total Drp1 and phosphor-Drp1 at Ser637, TGI induced a time-dependent increase of Drp1 phosphorlation at Ser616 that peaked after 24 h. Notably, PINK1-siRNA increased p-Drp1(Ser616) protein level in hippocampal CA1 subfield 24 h after TGI. The PINK1 siRNA also aggravated the TGI-induced oxidative DNA damage with an increased 8-hydroxy-deoxyguanosine (8-OHdG) content in hippocampal CA1 subfield. Furthermore, PINK1 siRNA also augmented TGI-induced apoptosis as evidenced by the increased numbers of TUNEL-positive staining and enhanced DNA fragmentation. These findings indicated that PINK1 is an endogenous protective mediator vital for neuronal survival under ischemic insult through regulating Drp1 phosphorylation at Ser616.

Co-upregulation of Toll-like receptors 2 and 6 on peripheral blood cells in patients with obstructive sleep apnea.

PURPOSE: Toll-like receptor (TLR) 2 can heterodimerise with TLR6 to detect diacylated lipoproteins. Hypoxia inducible factor-1 α co-ordinates selective induction of TLR2 and TLR6 during persistent hypoxia. We hypothesized that TLR 2/6 co-expression may be upregulated by chronic intermittent hypoxia with re-oxygenation (IHR) in obstructive sleep apnea (OSA). METHODS: TLR2/6 expressions on blood immune cells were measured in 144 patients with sleep-disordered breathing (SDB), including primary snoring (PS, n = 24), moderate to severe OSA (MSO, n = 60), very severe OSA (VSO, n = 36), and very severe OSA on continuous positive airway pressure (CPAP) treatment (VSOC, n = 24). An in vitro IHR experiment was also undertaken. RESULTS: Patients in both the MSO and VSO groups had increased TLR2/6 co-expression on CD16(+) neutrophil than those in the PS group. Patients in the VSOC group had reduced TLR2/6 co-expression on neutrophil than those in either the MSO or VSO group. Blood absolute neutrophil count was positively but weakly correlated with TLR2/6 co-expression on neutrophil. TLR2/6 co-expressions on both CD14(+) monocyte and CD3(+)CD4(+)T helper cell, and TLR2 expressions on both monocyte and T helper cell in SDB patients with low Minimum SaO2 (≦70%) were all higher than those with high Minimum SaO2. In vitro IHR for 1-4 days resulted in TLR2/6 co-upregulation on both neutrophil and monocyte. CONCLUSIONS: OSA patients had increased TLR2/6 co-expressions on blood immune cells, which were related to their immune cell counts and could be reversed with CPAP treatment. In vitro IHR could induce TLR2/6 co-upregulation.

Roles of Sestrin2 and Ribosomal Protein S6 in Transient Global Ischemia-Induced Hippocampal Neuronal Injury.

Recent studies suggested that sestrin2 is a crucial modulator for the production of reactive oxygen species (ROS). In addition, sestrin2 may also regulate ribosomal protein S6 (RpS6), a molecule important for protein synthesis, through the effect of mammalian target of rapamycin (mTOR) complex that is pivotal for longevity. However, the roles of sestrin2 in cerebral ischemia, in which oxidative stress is one of the major pathogenic mechanisms, are still less understood. In this study, we hypothesized that sestrin2 may protect hippocampal CA1 neurons against transient global ischemia (TGI)-induced apoptosis by regulating RpS6 phosphorylation in rats. We found that sestrin2 expression was progressively increased in the hippocampal CA1 subfield 1-48 h after TGI, reaching the maximal level at 24 h, and declined thereafter. Further, an increased extent of RpS6 phosphorylation, but not total RpS6 protein level, was observed in the hippocampal CA1 subfield after TGI. The sestrin2 siRNA, which substantially blocked the expression of TGI-induced sestrin2, also abolished RpS6 phosphorylation. TGI with reperfusion may induce oxidative stress with the resultant formation of 8-hydroxy-deoxyguanosine (8-OHdG). We found that sestrin2 siRNA further augmented the formation of 8-OHdG induced by TGI with reperfusion for 4 h. Consistently, sestrin2 siRNA also enhanced apoptosis induced by TGI with reperfusion for 48 h based on the analysis of DNA fragmentation by agarose gel electrophoresis, DNA fragmentation sandwich ELISA, and the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay. Together these findings indicated that TGI-induced sestrin2 expression contributed to RpS6 phosphorylation and neuroprotection against ischemic injury in the hippocampal CA1 subfield.

BNG-1 in the Recovery of Acute Ischemic Stroke: A phase 2, Double-blind, Placebo-controlled Randomized Trial.

PURPOSE: Few strategies have been approved for acute therapy of ischemic stroke in Western medicine. Hundreds of traditional Chinese medicines (TCMs) have been used for stroke therapy and were rarely tested by qualified studies. To evaluate the efficacy and safety of BNG-1, a novel mixture of TCMs, in patients with acute ischemic stroke, we conducted the clinical trial. METHODS: This was a Phase 2, double-blind, placebo-controlled study in which the safety and efficacy of orally administered BNG-1 based on oral aspirin 100 mg daily for consecutive 14 days were measured in patients with acute ischemic stroke within 10 days after onset. The primary efficacy endpoint was the functional status assessed by the Barthel Index. The safety was evaluated by the incidence of adverse events and significant changes in vital signs, parameters of physical and laboratory examinations. RESULTS: There were 42 patients randomized for the intention-to-treat efficacy analysis. The study failed to prove the significantly statistical difference of efficacy assessment between patients receiving BNG- 1 and placebo in the recovery of acute ischemic stroke. The clinical and laboratory safety profiles had no significant difference between two groups. CONCLUSIONS: BNG-1 trial was feasible, safe and well tolerated for patients with acute ischemic stroke based on the treatment of aspirin, though there was no statistically significant difference of efficacy between BNG-1 and placebo groups. A further large Phase 3 trial of BNG-1 is needed before recommending such treatments for general clinical use.

Heat shock protein 70 protects against seizure-induced neuronal cell death in the hippocampus following experimental status epilepticus via inhibition of nuclear factor-κB activation-induced nitric oxide synthase II expression.

Status epilepticus induces subcellular changes that may eventually lead to neuronal cell death in the hippocampus. Based on an animal model of status epilepticus, our laboratory showed previously that sustained hippocampal seizure activity activates nuclear factor-κB (NF-κB) and upregulates nitric oxide synthase (NOS) II gene expression, leading to apoptotic neuronal cell death in the hippocampus. The present study examined the potential modulatory role of heat shock protein 70 (HSP70) on NF-κB signaling in the hippocampus following experimental status epilepticus. In Sprague-Dawley rats, kainic acid (KA) was microinjected unilaterally into the hippocampal CA3 subfield to induce prolonged bilateral seizure activity. Expression of HSP70 was elevated as early as 1h after the elicitation of sustained seizure activity, followed by a progressive elevation that peaked at 24h. Pretreatment with an antisense oligonucleotide against hsp70 decreased the HSP70 expression, and significantly augmented IκB kinase (IKK) activity and phosphorylation of IκBα, alongside enhanced nuclear translocation and DNA binding activity of NF-κB in the hippocampal CA3 neurons and glial cells. These cellular events were followed by enhanced upregulation of NOS II and peroxynitrite expression 3h after sustained seizure activity that led to an increase of caspase-3 and DNA fragmentation in the hippocampal CA3 neurons 7days after experimental status epilepticus. We concluded that HSP70 protects against apoptotic cell death induced by NF-κB activation and NOS II-peroxynitrite signaling cascade in the hippocampal CA3 and glial cells following experimental status epilepticus via suppression of IKK activity and deactivation of IκBα.

High frequency of SPG4 in Taiwanese families with autosomal dominant hereditary spastic paraplegia.

BACKGROUND: Hereditary spastic paraplegias (HSPs) are a group of neurodegenerative diseases characterized by progressive spasticity and weakness of the lower limbs. SPG4, SPG3A and SPG31 are the three leading causes of autosomal dominant (AD) HSPs. METHODS: A total of 20 unrelated AD-HSP families were recruited for clinical and genetic assessment. Detection of mutations in SPG4, SPG3A and SPG31 genes was conducted according to a standard protocol. Genotype-phenotype correlations and determinants for disease severity and progression were analyzed. RESULTS: Mutations in the SPG4 gene (SPAST) were detected in 18 (90%) of the AD-HSP families. Mutations in SPG4, SPG3A and SPG31 genes were not detected in the remaining two families. Considerable variations in clinical features were noted, even for mutation carriers from the same family. Mutations causing complete loss of the spastin AAA cassette were associated with earlier onset of disease (20 ± 18 years) compared with those with preservation of partial or total AAA cassette (32 ± 19 years, p = 0.041). For those with SPG4 mutations, disease severity was related to the patients' current age, and the progression rate of disease was positively correlated with age at onset. CONCLUSIONS: SPG4 accounts for most of the AD-HSP cases in Taiwanese, with a frequency significantly higher than in other populations. SPAST mutations which predict complete loss of the spastin AAA cassette were associated with an earlier onset of disease.