AKAP3-mediated type I PKA signaling is required for mouse sperm hyperactivation and fertility†.

The protein kinase A (PKA) signaling pathway, which mediates protein phosphorylation, is important for sperm motility and male fertility. This process relies on A-kinase anchoring proteins that organize PKA and its signalosomes within specific subcellular compartments. Previously, it was found that the absence of A-kinase anchoring protein 3 (AKAP3) leads to multiple morphological abnormalities in mouse sperm. But how AKAP3 regulates sperm motility is yet to be elucidated. AKAP3 has two amphipathic domains, here named dual and RI, in its N-terminus. These domains are responsible for binding regulatory subunits I alpha (RIα) and II alpha (RIIα) of PKA and for RIα only, respectively. Here, we generated mutant mice lacking the dual and RI domains of AKAP3. It was found that the deletion of these domains caused male mouse infertile, accompanied by mild defects in the fibrous sheath of sperm tails. Additionally, the levels of serine/threonine phosphorylation of PKA substrates and tyrosine phosphorylation decreased in the mutant sperm, which exhibited a defect in hyperactivation under capacitation conditions. The protein levels of PKA subunits remained unchanged. But, interestingly, the regulatory subunit RIα was mis-localized from principal piece to midpiece of sperm tail, whereas this was not observed for RIIα. Further protein-protein interaction assays revealed a preference for AKAP3 to bind RIα over RIIα. Collectively, our findings suggest that AKAP3 is important for sperm hyperactivity by regulating type-I PKA signaling pathway mediated protein phosphorylation via its dual and RI domains.

Use of the redox-dependent intein system for enhancing production of the cyclic green fluorescent protein.

To expand the reported redox-dependent intein system application, in this work, we used the split intein variant with highly trans-splicing efficiency and minimal extein dependence to cyclize the green fluorescent protein variant reporter in vitro. The CPG residues were introduced adjacent to the intein's catalytic cysteine for reversible formation of a disulfide bond to retard the trans-splicing reaction under the oxidative environment. The cyclized reporter protein in Escherichia coli cells was easily prepared by organic extraction and identified by the exopeptidase digestion. The amounts of extracted cyclized protein reporter in BL21 (DE3) cells were higher than those in hyperoxic SHuffle T7 coexpression system for facilitating the disulfide bond formation. The double His6-tagged precursor was purified for in vitro cyclization of the protein for 3 h. Compared with the purified linear counterpart, the cyclic reporter showed about twofold increase in fluorescence intensity, exhibited thermal and hydrolytic stability, and displayed better folding efficiency in BL21 (DE3) cells at the elevated temperature. Taken together, the developed redox-dependent intein system will be used for producing other cyclic disulfide-free proteins. The cyclic reporter is a potential candidate applied in certain thermophilic aerobes.

Acrolein, an endogenous aldehyde induces Alzheimer's disease-like pathologies in mice: A new sporadic AD animal model.

Alzheimer's disease (AD) is a common neurodegenerative disease that mainly affects elderly people. However, the translational research of AD is frustrating, suggesting that the development of new AD animal models is crucial. By gavage administration of acrolein, we constructed a simple sporadic AD animal model which showed classic pathologies of AD in 1 month. The AD-like phenotypes and pathological changes were as followed. 1) olfactory dysfunctions, cognitive impairments and psychological symptoms in C57BL/6 mice; 2) increased levels of Aß1-42 and Tau phosphorylation (S396/T231) in cortex and hippocampus; 3) astrocytes and microglia proliferation; 4) reduced levels of postsynaptic density 95(PSD95) and Synapsin1, as well as the density of dendritic spines in the CA1 and DG neurons of the hippocampus; 5) high-frequency stimulation failed to induce the long-term potentiation (LTP) in the hippocampus after exposure to acrolein for 4 weeks; 6) decreased blood oxygen level-dependent (BOLD) signal in the olfactory bulb and induced high T2 signals in the hippocampus, which matched to the clinical observation in the brain of AD patients, and 7) activated RhoA/ROCK2/ p-cofilin-associated pathway in hippocampus of acrolein-treated mice, which may be the causes of synaptic damage and neuroinflammation in acrolein mice model. Taken together, the acrolein-induced sporadic AD mouse model closely reflects the pathological features of AD, which will be useful for the research on the mechanism of AD onset and the development of anti-AD drugs.

Frameshift mutation of Timm8a1 gene in mouse leads to an abnormal mitochondrial structure in the brain, correlating with hearing and memory impairment.

BACKGROUND: Deafness-dystonia-optic neuronopathy (DDON) syndrome is a progressive X-linked recessive disorder characterised by deafness, dystonia, ataxia and reduced visual acuity. The causative gene deafness/dystonia protein 1 (DDP1)/translocase of the inner membrane 8A (TIMM8A) encodes a mitochondrial intermembrane space chaperon. The molecular mechanism of DDON remains unclear, and detailed information on animal models has not been reported yet. METHODS AND RESULTS: We characterized a family with DDON syndrome, in which the affected members carried a novel hemizygous variation in the DDP1 gene (NM_004085.3, c.82C>T, p.Q28X). We then generated a mouse line with the hemizygous mutation (p.I23fs49X) in the Timm8a1 gene using the clustered regularly interspaced short palindromic repeats /Cas9 technology. The deficient DDP1 protein was confirmed by western blot assay. Electron microscopic analysis of brain samples from the mutant mice indicated abnormal mitochondrial structure in several brain areas. However, Timm8a1I23fs49X/y mutation did not affect the import of mitochondria inner member protein Tim23 and outer member protein Tom40 as well as the biogenesis of the proteins in the mitochondrial oxidative phosphorylation system and the manganese superoxide dismutase (MnSOD / SOD-2). The male mice with Timm8a1I23fs49X/y mutant exhibited less weight gain, hearing impairment and cognitive deficit. CONCLUSION: Our study suggests that frameshift mutation of the Timm8a1 gene in mice leads to an abnormal mitochondrial structure in the brain, correlating with hearing and memory impairment. Taken together, we have successfully generated a mouse model bearing loss-of-function mutation in Timm8a1.

Sex differences in growth performance are related to cecal microbiota in chicken.

In poultry industry, male chickens have a better growth performance than female ones under the same genetic background and diet. Emerging evidences proposed an important role of intestinal microbiota in chicken's growth performance. This study aimed to determine gut microbiota related gender based differences in the growth performance of chickens. Therefore, male and female chickens (n = 20) at 7-week age were used to carry out histomorphological, molecular, gene expression analysis with their liver, chest and leg muscle, as well as 16S rRNA sequencing analysis for gut microbiota. The results revealed that Bacteroides and Megamonas genera were more prominently colonized in the cecum of male chickens. The male chicken's cecal microbiota indicated a closer relation with glycan metabolism, while in the female chickens it was more related with lipid metabolism. Gene expression levels associated with glycan and lipid metabolism were different between male and female chickens. Further, using Spearman correlation analysis, we found a positive correlation between glycan and lipid metabolism, and the relative abundance of Bacteroides, Megamona and Lactobacillus in male chickens. Similarly, we also found a positive correlation between the lipid metabolism and the relative abundance of Ruminococcaceae and Enterococcus in female chickens. These findings revealed the association of chicken growth performance with cecal microbiota that contributed to the metabolism of glycan and lipid in a sex-dependent manner.

Combination of the mutations for improving activity of TEV protease in inclusion bodies.

Tobacco etch virus protease (TEVp) is an enzymatic reagent to remove fusion tag, but additional purification steps are required for removing the TEVp after cleavage reaction is finished. Use of carrier-free and dependent TEVp immobilizates can eliminate protease contamination. In this work, we identified that, among the four constructed missense variants, the insoluble variant with the highest activity was correspondent with the soluble one tested formerly. The activities of the insoluble 15 codon variants were assayed and the variant with highest activity was selected. The K45F and/or E106G mutations have been reported on slightly improving protein stability of the wild-type TEVp, but only E106G mutation enhanced soluble production and activity of the selected TEVp variant, and it increased soluble amounts of two codon variants with the impaired folding. The decreased activity and use efficiency of the optimized TEVp variant in inclusion bodies was balanced by the determined high level production, lower leaking amounts of the protein, the enhanced resistance to the limited proteolysis mediated by protease K and trypsin, and the increased inhibition of auto-cleavage, as comparison to those of the immobilized soluble one. Thus, the TEVp construct is a potential alternate for simplifying protein purification protocols after tag-removal.

Pseudorabies virus encephalitis in humans: a case series study.

Pseudorabies virus (PRV) is known to cause severe encephalitis in juvenile pigs and various non-native hosts; recent evidences suggest that PRV might cause encephalitis in humans. In a multicenter cohort study in China, next-generation sequencing of cerebrospinal fluid (CSF) was performed to detect pathogens in all patients with clinically suspected central nervous system infections. This study involved all the patients whose CSF samples were positive for PRV-DNA; their clinical features were evaluated, and species-specific PCR and serological tests were sequentially applied for validation. Among the 472 patients tested from June 1, 2016, to December 1, 2018, six were positive for PRV-DNA, which were partially validated by PCR and serological tests. Additionally, we retrospectively examined another case with similar clinical and neuroimaging appearance and detected the presence of PRV-DNA. These patients had similar clinical manifestations, including a rapid progression of panencephalitis, and similar neuroimaging features of symmetric lesions in the basal ganglia and bilateral hemispheres. Six of the patients were engaged in occupations connected with swine production. PRV infection should be suspected in patients with rapidly progressive panencephalitis and characteristic neuroimaging features, especially with exposure to swine.

Site-Specific Incorporation of Multiple Thioamide Substitutions into a Peptide Backbone via Solid Phase Peptide Synthesis.

Among various peptide modification strategies, thioamide substitution by replacing the carbonyl oxygen atom of an amide bond with a sulfur atom constitutes an invaluable tool for chemical biology, for use in peptide drug discovery and protein structure-function studies. However, the thioamide substitution effect has not been well studied because of the lack of synthetic methods for site-specifically incorporating a thioamide bond into a peptide backbone, particularly introducing multiple thioamide substitutions into peptide on a solid support. Herein, we report a highly efficient method for incorporating a thioamide bond into the peptide backbone in a site-specific manner by employing α-thioacyloxyenamides, which are formed from the addition of N-protected monothioamino acids and ynamides, as novel thioacylating reagents in solid phase peptide synthesis. This method is amenable for 19 of 20 proteinogenic amino acids, His being the exception. One to multiple thioamide substitutions could be incorporated into a growing peptide with no epimerization or a low level of epimerization. By using this method, a fully thioamide-substituted hexapeptide containing up to five continuous thioamide bonds could be synthesized smoothly. This synthetic methodology will spur the application of the thioamide substitution tool for protein engineering and peptide drug discovery.

Vibrio vulnificus meningoencephalitis in a patient with thalassemia and a splenectomy.

Vibrio vulnificus usually causes wound infection, gastroenteritis, and septicemia. However, it is a rare conditional pathogen causing meningoencephalitis. We report a case of a young, immunocompromised man presenting with severe sepsis after exposure to sea water and consumption of seafood. The patient subsequently developed meningoencephalitis, and Vibrio vulnificus was isolated from his blood culture. The sequence was confirmed by Next-generation sequencing of a sample of cerebrospinal fluid, as well as from a bacteria culture. After the pathogen was detected, the patient was treated with ceftriaxone, doxycycline, and moxifloxacin for 6 weeks, which controlled his infection. In this case, we acquired his clinical and dynamic MRI presentations, which were never reported. Physicians should consider Vibrio vulnificus infections when they see a similar clinical course, brain CT and MRI findings, susceptibility factors and recent seafood ingestion or exposure to seawater. Due to high mortality, the early diagnosis and treatment of Vibrio vulnificus infections are crucial. Next-generation sequencing was found to be useful for diagnosis.

Disruption of AT-hook 1 domain in MeCP2 protein caused behavioral abnormality in mice.

MECP2 is the causative gene for autism spectrum disorders, including Rett syndrome, a regressive neurodevelopmental rare disease mainly occurring in girls. Except for the distinct methyl-CpG binding domain and the transcriptional repression domain in MeCP2, three AT-hook-like domains have recently been identified. Several mutations in AT-hook 1 domain have been reported in autism cases or Rett database. However, the role of AT-hook 1 domain is still unclear. In this study, we generated a mouse line carrying deletion of eight conserved amino acids in AT-hook 1 domain by clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 technology. Mecp2ΔAT-hook1/y mutant male mice exhibited low locomotor activity, motor incoordination and cognitive deficit. In addition, these mutant mice exhibited increased anxiety. Moreover, pain insensitivity was noted in the mutant males. However, the social interactions were unaffected in AT-hook 1 mutant mice. Thinner CA1 region of the hippocampus was observed in the mutant mice. On the molecular basis, Western blot analysis showed increased expression of mutant MeCP2 protein in the cortex. Additionally, several genes expressed specifically in inhibitory neurons were markedly changed in the cerebrum. Taken together, these data demonstrate that disruption of AT-hook 1 domain in MeCP2 caused behavioral abnormality in mice, which suggests that AT-hook 1 is a critical region for the function of MeCP2 protein.

Cell permeable HMGB1-binding heptamer peptide ameliorates neurovascular complications associated with thrombolytic therapy in rats with transient ischemic stroke.

BACKGROUND: Blood-brain barrier (BBB) breakdown and inflammatory responses are the major causes of tissue-type plasminogen activator (tPA)-induced hemorrhagic transformation (HT), while high-mobility group box 1 (HMGB1) exacerbates inflammatory damage to BBB during the process of brain ischemia/reperfusion. This study aimed to investigate the change of HMGB1 after thrombolytic therapy and whether blocking HMGB1 could ameliorate the neurovasculature complications secondary to tPA treatment in stroke rats. METHODS: Sera from acute stroke patients and rats with thrombolytic therapy were collected to investigate HMGB1 secretion. Male Sprague-Dawley rats with 2 h or 4.5 h middle cerebral artery occlusion were continuously infused with tPA followed by administration of membrane permeable HMGB1-binding heptamer peptide (HBHP). The mortality rate, neurological score, HT, brain swelling, BBB permeability, and inflammatory factors were determined. RESULTS: The results revealed that HMGB1 levels were elevated in both stroke patients and rats after tPA treatment. Blocking HMGB1 signaling by HBHP in the rat model of 4.5 h brain ischemia significantly attenuated tPA-related complications, including mortality rate, the degree of hemorrhage, brain swelling, neurological deficits, BBB impairment, microglia activation, and the expressions of inflammatory cytokines. CONCLUSIONS: tPA treatment might induce HMGB1 secretion while blocking HMGB1 with HBHP could markedly reduce the risk of thrombolysis-associated brain hemorrhage and mortality through attenuating BBB damage and inflammatory reactions. These results indicate that HMGB1 may potentiate the risk of HT in tPA administration and that blocking HMGB1 signaling would be helpful in preventing complications brought by thrombolysis in ischemic stroke. TRIAL REGISTRATION: http://www.chictr.org.cn . Unique identifier: ChiCTR-OOC-16010052. Registered 30 November 2016.

Salmonella infection may alter the expression of toll like receptor 4 and immune related cells in chicken bursa of Fabricius.

Toll like receptor 4 (TLR4), eosinophils and mast cells play significant role in host immunity during several pathogenic infections. However in vivo tissue expression of TLR4 and distribution pattern of eosinophils and mast cells in chicken bursa of Fabricius (BF) during Salmonella enterica serovar Typhimurium (STm) infection is poorly studied. Therefore, herein, following immunostaining, we found localization of TLR4 in follicular cortex and medulla and its expression was statistical increased after 36 h and 72 h of STm stimulation. Chromotrope 2R staining revealed that eosinophils were mostly distributed in follicular cortex, inter-follicular spaces and in or around blood vessels and their number in BF were statistical increased after 72 h of STm stimulation. The presence of eosinophils was confirmed using immunostaining with anti-rabbit eosinophil cationic protein antibody. Toluidine blue stained mast cells were mostly distributed in connective tissues between inter-follicular spaces while some were also present in follicular cortex of BF. However, STm stimulation illustrated non-significant effect on the number of mast cells or their de-granulation, instead their number were gradually decreased in BF with advancement in age of chickens. Hence, this study provided novel information about in vivo tissue distribution of TLR4, eosinophils and mast cells in BF during STm infection.

Adeno-associated virus 9-mediated Cdk5 inhibitory peptide reverses pathologic changes and behavioral deficits in the Alzheimer's disease mouse model.

Cyclin-dependent kinase 5 (Cdk5), which binds to and is activated by p35, phosphorylates multiple substrates and plays an essential role in the development and function of the CNS; however, proteolytic production of p25 from p35 under stress conditions leads to the inappropriate activation of Cdk5 and contributes to hyperphosphorylation of τ and other substrates that are related to the pathogenesis of Alzheimer's disease. Selective inhibition of aberrant Cdk5 activity via genetic overexpression of Cdk5 inhibitory peptide (CIP) reduces pathologic changes and prevents brain atrophy and memory loss in p25-transgenic mice. In the present study, we delivered adeno-associated virus 9 carrying green fluorescent protein-CIP (AAV9-GFP-CIP) to brain cells via intracerebroventricular infusion in amyloid precursor protein/presenilin 1 (APP/PS1) double-transgenic 3-mo-old mice after the occurrence of ß-amyloid (Aß) aggregation and the hyperphosphorylation of τ. Three months of treatment of AAV9-GFP-CIP reduced pathologic changes, including τ hyperphosphorylation, (Aß) deposit, astrocytosis, and microgliosis, which were correlated with the reversal of memory loss and anxiety-like behavior observed in APP/PS1 mice. The neuroprotection effect of AAV9-GFP-CIP lasted an additional 7 mo-the end point of the study. These findings provide a novel strategy to selectively target Cdk5 for the treatment of Alzheimer's disease.-He, Y., Pan, S., Xu, M., He, R., Huang, W., Song, P., Huang, J., Zhang, H.-T., Hu, Y. Adeno-associated virus 9-mediated Cdk5 inhibitory peptide reverses pathologic changes and behavioral deficits in the Alzheimer's disease mouse model.

Toll like receptor 4 signaling pathway participated in Salmonella lipopolysaccharide-induced spleen injury in young chicks.

Spleen is one of the crucial sites for cellular and humoral immunity but it easily damaged during pathogenic infections resulting in immunosuppression. The current study was therefore performed to explore the mechanism of acute spleen injury induced by salmonella lipopolysaccharide (LPS) in young chicks. Healthy one-day-old Cobb strain broiler chicks were intra-peritoneally injected with saline or LPS. LPS treatment caused significant decreases in body and spleen weights at 36 and 72 h. Histological analysis showed the changes of ellipsoid structures with beginning of nuclear pyknosis and karyolysis similar to steatosis at 12 h, maximum histopathological lesions were seen at 36 h, however these were disappeared at 72 h post LPS stimulation. Cell proliferation was decreased (low PCNA positivity) and apoptosis increased (high ssDNA positivity) in the spleen at 12 and 36 h after LPS treatment. The expression levels of mRNA for caspase-3, caspase-8, B-cell lymphoma 2 (BCL-2), tumor protein p53 or p53 and Bcl-2 homologous antagonist killer (BAK) showed slight increase at some time points following LPS stimulation. LPS treatment also induced significant up-regulation in toll like receptor 4 (TLR4) at 36 h post LPS stimulation and slight increase in expressions of its downstream molecules (MyD88 and NF-κB) at 12 h post LPS treatment. The keystone cytokines (TNF-α and IL-6) exhibited significant up-regulation at 12 h following LPS stimulation. Our findings provided novel information about the histopathological as well as apoptotic and proliferative alterations in spleen mediated by TLR4 signaling induced by Salmonella LPS in avian species.

Preconditioning with recombinant high-mobility group box 1 induces ischemic tolerance in a rat model of focal cerebral ischemia-reperfusion.

Preconditioning with ligands of toll-like receptors (TLRs) is a powerful neuroprotective approach whereby a low dose of stimulus confers significant protection against subsequent substantial brain damage by reprogramming the ischemia-activated TLRs signaling. Herein, we aim to explore whether preconditioning with recombinant high-mobility group box 1 (rHMGB1), one of the TLRs ligands, decreases cerebral ischemia-reperfusion injury (IRI). Rats were intracerebroventricularly pretreated with rHMGB1, 1 or 3 days before induction of middle cerebral artery occlusion. Results showed that preconditioning with rHMGB1 1 day, but not 3 days, prior to ischemia dramatically reduced neurological deficits, infarct size, brain swelling, cell apoptosis, and blood-brain barrier permeability. Interleukin-1R-associated kinase-M (IRAK-M), a critical negative regulator of TLRs signaling, was robustly increased in response to brain IRI and was further elevated by rHMGB1 pretreatment, indicating its role associated with the rHMGB1 preconditioning-mediated ischemic tolerance. In vitro and in vivo assays indicated that the induced IRAK-M expression was localized in microglia. In addition, TLR4 specific inhibitor TAK-242 abolished the neuroprotective effects and the induction of IRAK-M offered by rHMGB1 preconditioning. Collectively, our study demonstrates that rHMGB1 preconditioning is neuroprotective during cerebral IRI, which is associated with activated TLR4/IRAK-M signaling in microglia. We found that high-mobility group box 1 (HMGB1) pretreatment conditioned the brain against subsequent ischemia-reperfusion injury. We propose the following mechanism for HMGB1 preconditioning-mediated ischemic tolerance: through toll-like receptor TLR4, HMGB1 preconditioning magnifies the up-regulation of interleukin-1R-associated kinase-M (IRAK-M) induced by ischemia-reperfusion in microglia, resulting in the decreased phosphorylation of IRAK-1. These findings are helpful in understanding the endogenous mechanisms that counteract ischemic insults.

Hypothermia followed by rapid rewarming exacerbates ischemia-induced brain injury and augments inflammatory response in rats.

Hypothermia followed by slow rewarming is neuroprotective for ischemic stroke. However, slow rewarming causes patients' longer stay in intensive care unit and increases the risk of hypothermic complications. Hypothermia followed by rapid rewarming (HTRR) is more convenient; but it exacerbates intracranial hypertension for patients with massive hemispheric infarcts. The present study aims to investigate in detail how HTRR exacerbates ischemic brain injury and what are underlying mechanisms. Rats subjected to transient focal ischemia by middle cerebral artery occlusion were treated with normothermia or hypothermia followed by rapid rewarming. Neurological outcome, neuronal injury, blood-brain barrier integrity and expressions of inflammatory cytokines were observed. Results showed that HTRR at a rate of 3 °C/20 min increased both neurological deficit score and Longa score, enhanced the loss of neurons and the plasma level of neuron-specific enolase. Rapid rewarmed rats also displayed increased Evans blue dye extravasation, matrix metalloproteinase 9 level and tight junction impairment. Meanwhile, interleukin-1ß, -6, tumor necrosis factor α and cyclooxygenase-2 were markedly elevated in rapid rewarmed rats. Anti-inflammatory agent minocycline suppressed HTRR-induced elevation of inflammatory cytokines and improved neurological outcome. These results indicated that HTRR significantly impaired neurovascular unit and augmented proinflammatory response in stroke.

Prolonged hypothermia exposure diminishes neuroprotection for severe ischemic-hypoxic primary neurons.

This study aimed to identify optimal mild hypothermic (MH) condition that would provide the best protection for neuronal cells undergoing severe ischemia and hypoxia. We also sought to determine if longer exposure to mild hypothermia would confer greater protection to severe ischemia and hypoxia in these cells. We designed a primary neuronal cell model for severe glucose and oxygen deprivation/reoxygenation (OGD/R) to simulate the hypoxic-ischemic condition of patients with severe stroke, trauma, or hypoxic-ischemic encephalopathy. We evaluated the viability of these neurons following 3 h of OGD/R and variable MH conditions including different temperatures and durations of OGD/R exposure. We further explored the effects of the optimal MH condition on several parts which are associated with mitochondrial apoptosis pathway: intracellular calcium, reactive oxygen species (ROS), and mitochondrial transmembrane potential (MTP). The results of this study showed that the apoptosis proportion (AP) and cell viability proportion (CVP) after OGD/R significantly varied depending on which MH condition cells were exposed to (p < 0.001). Further, our findings showed that prolonged MH reduced the neuroprotection to AP and CVP. We also determined that the optimal MH conditions (34 °C for 4.5 h) reduced intracellular calcium, ROS, and recovered MTP. These findings indicate that there is an optimal MH treatment strategy for severely hypoxia-ischemic neurons, prolonged duration might diminish the neuroprotection, and that MH treatment likely initiates neuroprotection by inhibiting the mitochondrial apoptosis pathway.

Glibenclamide Improves Survival and Neurologic Outcome After Cardiac Arrest in Rats.

OBJECTIVES: Glibenclamide confers neuroprotection in animal models as well as in retrospective clinical studies. This study determines whether glibenclamide improves outcome after cardiac arrest in rats. DESIGN: Prospective randomized laboratory study. SETTING: University research laboratory. SUBJECTS: Male Sprague-Dawley rats (n = 126). INTERVENTIONS: Rats successfully resuscitated from 8-minute asphyxial cardiac arrest were randomized to glibenclamide or vehicle group. Rats in the glibenclamide group were intraperitoneally administered glibenclamide with a loading dose of 10 µg/kg at 10 minutes and a maintenance dose of 1.2 µg at 6, 12, 18, and 24 hours after return of spontaneous circulation, whereas rats in the vehicle group received equivalent volume of vehicle solution. MEASUREMENTS AND MAIN RESULTS: Survival was recorded every day, and neurologic deficit scores were assessed at 24, 48, and 72 hours and 7 days after return of spontaneous circulation (n = 22 in each group). Results showed that glibenclamide treatment increased 7-day survival rate, reduced neurologic deficit scores, and prevented neuronal loss in the hippocampal cornu ammonis 1 region. To investigate the neuroprotective effects of glibenclamide in acute phase, we observed neuronal injury at 24 hours after return of spontaneous circulation and found that glibenclamide significantly decreased the rate of neuronal necrosis and apoptosis. In addition, glibenclamide reduced the messenger RNA expression of tumor necrosis factor-α and monocyte chemoattractant protein-1 in the cortex after return of spontaneous circulation. Furthermore, the sulfonylurea receptor 1 and transient receptor potential M4 heteromers, the putative therapeutic targets of glibenclamide, were up-regulated after cardiac arrest and cardiopulmonary resuscitation, indicating that they might be involved in neuroprotective effect of glibenclamide. CONCLUSIONS: Glibenclamide treatment substantially improved survival and neurologic outcome throughout a 7-day period after return of spontaneous circulation. The salutary effects of glibenclamide were associated with suppression of neuronal necrosis and apoptosis, as well as inflammation in the brain.

Neurosyphilis complicated by anti-γ-aminobutyric acid-B receptor encephalitis: A case report.

BACKGROUND: Syphilis is an infectious disease caused by Treponema pallidum that can invade the central nervous system, causing encephalitis. Few cases of anti-N-methyl-D-aspartate receptor autoimmune encephalitis (AE) secondary to neurosyphilis have been reported. We report a neurosyphilis patient with anti-γ-aminobutyric acid-B receptor (GABABR) AE. CASE SUMMARY: A young man in his 30s who presented with acute epileptic status was admitted to a local hospital. He was diagnosed with neurosyphilis, according to serum and cerebrospinal fluid (CSF) tests for syphilis. After 14 d of antiepileptic treatment and anti-Treponema pallidum therapy with penicillin, epilepsy was controlled but serious cognitive impairment, behavioral, and serious psychiatric symptoms were observed. He was then transferred to our hospital. The Mini-Mental State Examination (MMSE) crude test results showed only 2 points. Cranial magnetic resonance imaging revealed significant cerebral atrophy and multiple fluid-attenuated inversion recovery high signals in the white matter surrounding both lateral ventricles, left amygdala and bilateral thalami. Anti-GABABR antibodies were discovered in CSF (1:3.2) and serum (1:100). The patient was diagnosed with neurosyphilis complicated by anti-GABABR AE, and received methylprednisolone and penicillin. Following treatment, his mental symptoms were alleviated. Cognitive impairment was significantly improved, with a MMSE of 8 points. Serum anti-GABABR antibody titer decreased to 1:32. The patient received methylprednisolone and penicillin after discharge. Three months later, the patient's condition was stable, but the serum anti-GABABR antibody titer was 1:100. CONCLUSION: This patient with neurosyphilis combined with anti-GABABR encephalitis benefited from immunotherapy.

Secondary immunoreaction in patients with neurosyphilis and its relevance to clinical outcomes.

Background and purpose: Several reported cases of autoimmune conditions such as anti-NMDAR encephalitis and neuromyelitis optica (AQP4) have been considered to be potentially secondary to Treponema pallidum infection. Since the role of immune impairment in neurosyphilis is unclear, in this retrospective study, we examined the correlation of the immune impairment in patients with neurosyphilis with their clinical characteristics and outcomes. Methods: Clinical information was collected from patients with neurosyphilis in our center from January 2019 to December 2021. Cerebrospinal fluid (CSF) samples were subjected to indirect immunofluorescence tissue-based assay (IIF-TBA) on mouse brain sections and cell-based assay (CBA). The clinical characteristics and treatment outcomes of TBA-positive and-negative patients were compared. Results: A total number of 81 patients diagnosed with neurosyphilis were included. The results of the CBA tests showed that three cases had anti-NMDAR, AQP4, or GAD65 antibodies, respectively. By TBA test, 38 patients (38/81, 46.9%) had positive immunostains, including staining of neuronal cells in 21 cases (21/38, 55.3%), glial cells in 11 cases (11/38, 28.9%), and neuronal and glial cells in six cases (6/38, 15.8%). We then compared the clinical characteristics and treatment outcomes between the TBA-positive and-negative patients and found that TBA-positive staining was significantly correlated with syphilis antibody titers (p = 0.027 for serum and p = 0.006 for CSF) and head MRI abnormalities (p < 0.001 for parenchymal abnormalities and p = 0.013 for white matter lesions). The cognitive prognosis of TBA-positive neurosyphilis patients was significantly worse than that of TBA-negative patients (p < 0.001). Conclusion: The correlation between the TBA results and clinical data of our neurosyphilis patients imply the presence of secondary immune damage, which affected their prognosis. Therefore, TBA can be used as an additional biomarker for neurosyphilis patient prognosis.