p53-dependent crosstalk between DNA replication integrity and redox metabolism mediated through a NRF2-PARP1 axis.

Mechanisms underlying p53-mediated protection of the replicating genome remain elusive, despite the quintessential role of p53 in maintaining genomic stability. Here, we uncover an unexpected function of p53 in curbing replication stress by limiting PARP1 activity and preventing the unscheduled degradation of deprotected stalled forks. We searched for p53-dependent factors and elucidated RRM2B as a prime factor. Deficiency in p53/RRM2B results in the activation of an NRF2 antioxidant transcriptional program, with a concomitant elevation in basal PARylation in cells. Dissecting the consequences of p53/RRM2B loss revealed a crosstalk between redox metabolism and genome integrity that is negotiated through a hitherto undescribed NRF2-PARP1 axis, and pinpoint G6PD as a primary oxidative stress-induced NRF2 target and activator of basal PARylation. This study elucidates how loss of p53 could be destabilizing for the replicating genome and, importantly, describes an unanticipated crosstalk between redox metabolism, PARP1 and p53 tumor suppressor pathway that is broadly relevant in cancers and can be leveraged therapeutically.

The Wnt/Ca2+ pathway is involved in interneuronal communication mediated by tunneling nanotubes.

Tunneling nanotubes (TNTs) are actin-based transient tubular connections that allow direct communication between distant cells. TNTs play an important role in several physiological (development, immunity, and tissue regeneration) and pathological (cancer, neurodegeneration, and pathogens transmission) processes. Here, we report that the Wnt/Ca2+ pathway, an intracellular cascade that is involved in actin cytoskeleton remodeling, has a role in TNT formation and TNT-mediated transfer of cargoes. Specifically, we found that Ca2+ /calmodulin-dependent protein kinase II (CaMKII), a transducer of the Wnt/Ca2+ pathway, regulates TNTs in a neuronal cell line and in primary neurons. We identified the ß isoform of CaMKII as a key molecule in modulating TNT formation and transfer, showing that this depends on the actin-binding activity of the protein. Finally, we found that the transfer of vesicles and aggregated α-synuclein between primary neurons can be regulated by the activation of the Wnt/Ca2+ pathway. Our findings suggest that Wnt/Ca2+ pathway could be a novel promising target for therapies designed to impair TNT-mediated propagation of pathogens.

Global fitness landscapes of the Shine-Dalgarno sequence.

Shine-Dalgarno sequences (SD) in prokaryotic mRNA facilitate protein translation by pairing with rRNA in ribosomes. Although conventionally defined as AG-rich motifs, recent genomic surveys reveal great sequence diversity, questioning how SD functions. Here, we determined the molecular fitness (i.e., translation efficiency) of 49 synthetic 9-nt SD genotypes in three distinct mRNA contexts in Escherichia coli We uncovered generic principles governing the SD fitness landscapes: (1) Guanine contents, rather than canonical SD motifs, best predict the fitness of both synthetic and endogenous SD; (2) the genotype-fitness correlation of SD promotes its evolvability by steadily supplying beneficial mutations across fitness landscapes; and (3) the frequency and magnitude of deleterious mutations increase with background fitness, and adjacent nucleotides in SD show stronger epistasis. Epistasis results from disruption of the continuous base pairing between SD and rRNA. This "chain-breaking" epistasis creates sinkholes in SD fitness landscapes and may profoundly impact the evolution and function of prokaryotic translation initiation and other RNA-mediated processes. Collectively, our work yields functional insights into the SD sequence variation in prokaryotic genomes, identifies a simple design principle to guide bioengineering and bioinformatic analysis of SD, and illuminates the fundamentals of fitness landscapes and molecular evolution.

Evaluation of ESAT6-CFP10 Skin Test for Mycobacterium tuberculosis Infection among Persons Living with HIV in China.

Recent global guidelines recommend Mycobacterium tuberculosis antigen-based skin tests, such as the ESAT6-CFP10 (EC) skin test, as acceptable alternatives to the tuberculin skin test (TST) and the QuantiFERON-TB Gold In-Tube test (QFT). However, the diagnostic value of these tests among persons living with HIV (PLHIV) is unknown. We aimed to assess the diagnostic accuracy of the EC among a cohort of PLHIV in China. We recruited PLHIV in Jiangsu Province, China, to assess sensitivity and specificity of the EC test. Participants were tested with the QFT, TST, and EC skin test. Results were stratified by age, M. tuberculosis BCG vaccination, and CD4 count. The sensitivity and specificity of the EC skin test was assessed using distinct cutoffs of the QFT and TST. Of 350 PLHIV enrolled in the study, 58 (16.6%), 89 (25.4%), and 59 (16.9%) tested positive with the EC test, the QFT, and the TST, respectively. Positivity increased with CD4 count; however, these trends were similar across tests. At a 5-mm cutoff, EC skin test specificity was high (99.6%, 95% confidence interval [CI] 95% CI = 97.7 to 100.0); however, sensitivity was moderate (81.4%; 95% CI = 66.6 to 91.6). After stratifying by BCG, the sensitivity and specificity were 86.4% (95% CI = 65.1 to 97.1) and 99.1% (95% CI = 95.0 to 100.0) among vaccinated PLHIV and 76.2% (95% CI = 52.8 to 91.8) and 100.0% (95% CI = 97.2 to 100.0) among unvaccinated PLHIV, respectively. Among PLHIV, the diagnostic value of the EC skin test remained high, regardless of BCG vaccination or CD4 count. The EC skin test performed comparably to TST and may be a valid alternative diagnostic test to use in settings or populations with high HIV prevalence and BCG vaccination. To our knowledge, this is the first study to evaluate the novel ESAT6-CFP10 skin test among PLHIV. Among 350 PLHIV, the test displayed high specificity and sensitivity, a finding which did not markedly differ based on BCG vaccination and CD4 count.

Comparison of long-term effects of exergaming (Xbox one kinet) and companionship programs on attitude towards dementia and the older adults among adolescents: a quasi-experimental longitudinal study.

BACKGROUND: Many studies have been performed on the use of intergenerational programs to improve the negative attitudes and misunderstandings of adolescents toward older people with dementia. However, the findings of these studies are inconclusive. The aim of this study was to compare the long-term effects of exergaming (Kinect) and companionship programs on attitudes toward dementia and the elderly among adolescents. METHODS: A quasi-experimental longitudinal design was used. A total of 200 adolescents aged 12-18 years old were recruited from nine schools in northern Taiwan. The adolescents were assigned to five different groups, namely, a 5-week exergaming group, a 5-week companion group, an 8-week exergaming group, an 8-week companion group, and a control group, using a single blinding procedure. Data collection was performed pretest, post-test and at 1, 3 and 6 months after the post-test. The long-term effects of the two programs (i.e., exergaming and companionship) were analyzed using a generalized estimating equation. RESULTS: Regarding attitudes toward dementia, the 8-week exergaming group had a significantly better attitude than the control group at the 6-month follow-up (p < 0.001). Similarly, the results of the 8-week companion group also showed a significantly improved attitude compared with the control group at the 6-month follow-up (p = 0.041). Regarding attitudes toward the elderly, the 8-week exergaming group had a significantly better attitude than the control group at the 6-month follow-up (p < 0.001). The 8-week companion group had a similar effect on better attitude compared with the control group at the 6-month follow-up (p = 0.016). Furthermore, the 5-week companion group showed a significant improvement compared with the control group at the 6-month follow-up (p = 0.004). CONCLUSIONS: Spending companionship time with older adults is beneficial for improving the attitudes of adolescents toward the elderly. Furthermore, exergaming improves the attitudes of adolescents toward both dementia and older adults. TRIAL REGISTRATION: Chinese Clinical Trial Registry: ChiCTR2100053003 . Retrospectively registered on 07/11/2021.

The QseEF Two-Component System-GlmY Small RNA Regulatory Pathway Controls Swarming in Uropathogenic Proteus mirabilis.

Bacterial sensing of environmental signals through the two-component system (TCS) plays a key role in modulating virulence. In the search for the host hormone-sensing TCS, we identified a conserved qseEGF locus following glmY, a small RNA (sRNA) gene in uropathogenic Proteus mirabilis. Genes of glmY-qseE-qseG-qseF constitute an operon, and QseF binding sites were found in the glmY promoter region. Deletion of glmY or qseF resulted in reduced swarming motility and swarming-related phenotypes relative to the wild-type and the respective complemented strains. The qseF mutant had decreased glmYqseEGF promoter activity. Both glmY and qseF mutants exhibited decreased flhDC promoter activity and mRNA level, while increased rcsB mRNA level was observed in both mutants. Prediction by TargetRNA2 revealed cheA as the target of GlmY. Then, construction of the translational fusions containing various lengths of cheA 5'UTR for reporter assay and site-directed mutagenesis were performed to investigate the cheA-GlmY interaction in cheA activation. Notably, loss of glmY reduced the cheA mRNA level, and urea could inhibit swarming in a QseF-dependent manner. Altogether, this is the first report elucidating the underlying mechanisms for modulation of swarming motility by a QseEF-regulated sRNA GlmY, involving expression of cheA, rcsB and flhDC in uropathogenic P. mirabilis.

Postvaccinal Encephalopathy Presenting with Amnesia and Seizure After ChAdOx1 nCov-19 Vaccination: A Case Report.

PURPOSE: Because of the COVID-19 pandemic and resulting widespread vaccination, many related neurological disorders, including autoimmune encephalopathy, have emerged. The pathophysiological mechanism underlying the COVID-19 vaccination and autoimmune encephalopathy remains unclear; more case reports and further investigation are required. CASE REPORT: We report a clinical case of a 38-year-old woman who presented with acute-onset amnesia, language disturbance, and seizure. We suspected autoimmune encephalopathy triggered by the ChAdOx1 nCoV-19 vaccine. Brain magnetic resonance imaging revealed a subacute infarction at the right internal capsule and irregular vascular contour, which indicated a vasculopathy, such as vasculitis. Cerebrospinal fluid analysis revealed inflammation without pleocytosis, and electroencephalography detected diffuse background slowing with sharp transients at the right temporal region. Although autoantibody tests were negative, we initiated steroid pulse therapy. The patient's symptoms improved rapidly. The patient was discharged without neurological deficit or sequelae. CONCLUSION: Clinicians should be mindful of postvaccinal encephalopathy and suspect this condition in patients with acute onset of psychosis or mental change, higher cortical dysfunction, and seizure within 2 weeks of vaccination. Early diagnosis is key, and immune treatment, such as steroid pulse therapy or immunosuppressants, may dramatically improve patients'symptoms.

Controllable ion transport induced by pH gradient in a thermally crosslinked submicrochannel heterogeneous membrane.

Solid-state nanochannels have attracted considerable attention for their similar ion transport properties to biological ion channels. The construction of porous ion channels with good stability at the submicro/micrometer scale is very beneficial to develop large-area ion channel devices. In this manuscript, based on in-situ thermal crosslinking of a small organic molecule containing triphenylamine and styrene groups, we construct a heterogeneous membrane with asymmetrical charge and wettability on cylindrical anodic aluminum oxide (AAO) channels (D ≈ 319 nm). This heterogeneous membrane has typical ion current rectification characteristics with a high rectification ratio of 36.9 and good stability. This work provides an effective strategy for the construction of submicrochannel heterogeneous membranes and also broadens the application range of bionic ion channels.

Percutaneous Interstitial Nd:YAG Laser Therapy for Axillary Osmidrosis.

BACKGROUND AND OBJECTIVES: To investigate the effects of percutaneous interstitial Nd:YAG laser irradiation on the apocrine glands and molecules involved in odor production (apolipoprotein [ApoD], androgen receptor [AR]) in the subcutaneous tissue of a pig. STUDY DESIGN/MATERIALS AND METHODS: Skin on the back of healthy adult miniature pigs was exposed to pulsed Nd:YAG laser irradiation at 5 or 10 W, or continuous Nd:YAG laser irradiation at 10 W. Samples were taken 1 hour, 1 week, and 1 month after treatment for histology, western blot, and real-time quantitative polymerase chain reaction (qRT-PCR) analysis. RESULTS: One week and 1 month after irradiation, the apocrine glands in pigskin became rounded, glandular cells were shorter, and the glandular cavities were larger compared with controls, but there were no obvious changes in fat cell distribution of collagen around the apocrine glands. One month after irradiation at 10 W in continuous mode, there was a significant decrease in ApoD expression in apocrine cells and ApoD and AR protein and expression levels in pigskin compared with controls. There were also significant differences in ApoD and AR protein and expression levels between treatments. CONCLUSIONS: Percutaneous interstitial Nd:YAG laser irradiation has potential as a safe and efficacious treatment for axillary osmidrosis as it may decrease the production of volatile unsaturated fatty acids, steroids, and associated unpleasant odors in the axilla. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.

The efficacy of pentosan polysulfate monotherapy for preventing recurrent urinary tract infections in women: A multicenter open-label randomized controlled trial.

BACKGROUND/PURPOSE: Pentosan polysulfate sodium (PPS), a semi-synthetic polysaccharide that adheres to bladder mucosa, is effective in treating interstitial cystitis. We evaluated the clinical benefit of PPS for the prevention of recurrent urinary tract infection (UTI) in women. METHODS: We conducted a multicenter, open-label, prospective, phase II, randomized controlled trial enrolling women with recurrent UTI ≥ 2 times in the past 6 months or ≥ 3 times in the past 12 months. Patients received oral PPS monotherapy for 16 weeks in treatment group. All patients were followed every 28 days until UTI recurrence or up to 112 days. The primary endpoint was the UTI recurrence-free survival. Adverse events were recorded as secondary endpoint. RESULTS: A total of 26 women were eligible for analysis. In the PPS group, none (0%) of the 12 patients had UTI recurrence during the study period. However, 9 (64%) of 14 patients had UTI recurrence in the control group. The UTI recurrence-free survival was significantly higher in the PPS group than in the control group (log-rank test p = 0.0004). One adverse event which led to discontinuation of the trial regimen was regarded as irrelevance of PPS treatment. The limitation was the small number of cases. CONCLUSION: Among women with recurrent UTI, 16-week PPS monotherapy significantly reduced UTI recurrence when compared with the control group.

Altered inhibition and excitation in neocortical circuits in congenital microcephaly.

Congenital microcephaly is highly associated with intellectual disability. Features of autosomal recessive primary microcephaly subtype 3 (MCPH3) also include hyperactivity and seizures. The disease is caused by biallelic mutations in the Cyclin-dependent kinase 5 regulatory subunit-associated protein 2 gene CDK5RAP2. In the mouse, Cdk5rap2 mutations similar to the human condition result in reduced brain size and a strikingly thin neocortex already at early stages of neurogenesis that persists through adulthood. The microcephaly phenotype in MCPH arises from a neural stem cell proliferation defect. Here, we report a novel role for Cdk5rap2 in the regulation of dendritic development and synaptogenesis of neocortical layer 2/3 pyramidal neurons. Cdk5rap2-deficient murine neurons show poorly branched dendritic arbors and an increased density of immature thin spines and glutamatergic synapses in vivo. Moreover, the excitatory drive is enhanced in ex vivo brain slice preparations of Cdk5rap2 mutant mice. Concurrently, we show that pyramidal neurons receive fewer inhibitory inputs. Together, these findings point towards a shift in the excitation - inhibition balance towards excitation in Cdk5rap2 mutant mice. Thus, MCPH3 is associated not only with a neural progenitor proliferation defect but also with altered function of postmitotic neurons and hence with altered connectivity.

High-Throughput, Sensitive LC-MS Quantification of Biotherapeutics and Biomarkers Using Antibody-Free, Peptide-Level, Multiple-Mechanism Enrichment via Strategic Regulation of pH and Ionic and Solvent Strengths.

Sensitive and high-throughput measurement of biotherapeutics and biomarkers in plasma and tissues is critical for protein-drug development. Enrichment of target signature peptide (SP) after sample digestion permits sensitive LC-MS-based protein quantification and carries several prominent advantages over protein-level enrichment; however, developing high-quality antipeptide antibodies is challenging. Here we describe a novel, antibody-free, peptide-level-enrichment technique enabling high-throughput, sensitive, and robust quantification of proteins in biomatrices, by highly selective removal of matrix peptides and components via cation-exchange (CX) reversed-phase (RP) SPE with strategically regulated pH and ionic and organic strengths. Multiple-mechanism washing and elution achieved highly selective separation despite the low plate number of the SPE cartridge. We first investigated the adsorption-desorption behaviors of peptides on CX-RP sorbent and the coexisting, perplexing effects of pH, and ionic and organic strengths on the selectivity for SP enrichment, which has not been previously characterized. We demonstrated that the selectivity for separating target SPs from matrix peptides was closely associated with buffer pH relative to the pI of the SP, and pH values of pI - 2, pI, and pI + 2 respectively provided exceptional specificity for the ionic wash, the hydrophobic wash, and selective elution. Furthermore, desorption of peptides from the mixed-mode sorbent showed exponential and linear dependence, respectively, on organic-solvent percentage and salt percentage. On the basis of these findings, we established a streamlined procedure for rapid and robust method development. Quantification of biotherapeutics, targets, and biomarkers in plasma and tissues was used as the model system. Selective enrichment of target SPs was achieved along with elimination of 87-95% of matrix peptides, which improved the LOQ by 20-fold (e.g., 2 ng per gram of tissue). Application was demonstrated by sensitive quantification of time courses of mAb (T84.66) and target (CEA) in plasma and tumor tissues from a low-dose mouse PK study. For the first time, down-regulation of membrane-associated antigen following mAb treatment was observed. The CX-RP enrichment is robust, high-throughput, and universally applicable and thus is highly valuable for ultrasensitive, large-scale measurement of target protein in plasma and tissues.

Comparison of single and tandem ureteral stenting for malignant ureteral obstruction: a prospective study of 104 patients.

OBJECTIVES: The aim of this study was to compare single and tandem ureteral stenting in the management of malignant ureteral obstruction (MUO). METHODS: Our hospital's institutional review board approved this prospective study. Between November 2014 and June 2017, single ureteral stenting was performed in 56 patients (94 renal units) and tandem ureteral stenting in 48 patients (63 renal units) for MUO. A comparative analysis of the technical success rate, patient survival, stent patency, and complications was performed. RESULTS: Similar demographic data were observed in patients receiving either single or tandem ureteral stenting. The technical success rate was 93.6% (88/94) for single ureteral stenting and 95.2% (60/63) for tandem ureteral stenting. There was no difference in overall survival between patients receiving single or tandem ureteral stenting (p = 0.41), but the duration of stent patency in tandem ureteral stenting was significantly longer (p = 0.022). The mean patency time was 176.7 ± 21.3 days for single ureteral stenting, and 214.7 ± 21.0 days for tandem ureteral stenting. The complications of ureteral stenting were urinary tract infection (n = 18), lower urinary tract symptoms (n = 5), haematuria (n = 3), and stent migration (n = 1). CONCLUSIONS: Tandem ureteral stenting is a safe and feasible treatment for MUO, and had better efficacy compared to single ureteral stenting. KEY POINTS: • Ureteral stenting is an established treatment for the management of malignant ureteral obstruction (MUO) • Prospective single-centre study showed that tandem ureteral stenting is a safe and feasible treatment for MUO • Tandem ureteral stenting provides longer stent patency compared to single ureteral stenting in patient with MUO.

The application of p2PSA% and prostate health index in prostate cancer detection: A prospective cohort in a Tertiary Medical Center.

BACKGROUND/PURPOSE: Prostate specific antigen (PSA) with low specificity that causes unnecessary prostate biopsies increases clinical morbidities, psychological stress, and medical expenses. We aimed to test the accuracy and cutoff value of Prostate Health Index (PHI) in men for prostate cancer detection. METHODS: We prospectively enrolled 213 men who underwent prostate biopsy with PSA≦10 ng/ml or abnormal findings on digital rectal examination. Total PSA (tPSA), free PSA (fPSA) and p2PSA levels were measured by serum samples before prostate biopsy. PHI was calculated as (p2PSA/fPSA) × âˆštPSA. Multivariable logistic regression analyses were used to predict the risk of cancer and detect clinically significant prostate cancer. RESULTS: 33 (27.0%) patients were confirmed with the diagnoses of prostate cancer by prostate biopsy. The levels of p2PSA, %p2PSA, and PHI showed statistically significant differences between prostate cancer patients and non-cancer patients. %p2PSA and PHI had the highest area under the receiver operating characteristic curve (AUC) of 0.723 and 0.772 (both p < 0.001), respectively, predicting cancer detection at biopsy than other predictors (tPSA, fPSA, %fPSA, and PSA density (AUC: 0.544, 0.538, 0.593, and 0.664, respectively). In multivariable logistic regression, %p2PSA had a statistical significant odds ratio 8.51 (p = 0.003) and PHI had an odds ratio with marginal significance 4.18 (p = 0.06). CONCLUSION: %p2PSA and PHI increased the diagnostic accuracy with significantly greater sensitivity and specificity than tPSA. We determined an optimal cut-off value of PHI among Taiwanese population. These findings support the usefulness in the decisional process of prostate biopsy.

Sensitive, High-Throughput, and Robust Trapping-Micro-LC-MS Strategy for the Quantification of Biomarkers and Antibody Biotherapeutics.

For LC-MS-based targeted quantification of biotherapeutics and biomarkers in clinical and pharmaceutical environments, high sensitivity, high throughput, and excellent robustness are all essential but remain challenging. For example, though nano-LC-MS has been employed to enhance analytical sensitivity, it falls short because of its low loading capacity, poor throughput, and low operational robustness. Furthermore, high chemical noise in protein bioanalysis typically limits the sensitivity. Here we describe a novel trapping-micro-LC-MS (T-µLC-MS) strategy for targeted protein bioanalysis, which achieves high sensitivity with exceptional robustness and high throughput. A rapid, high-capacity trapping of biological samples is followed by µLC-MS analysis; dynamic sample trapping and cleanup are performed using pH, column chemistry, and fluid mechanics separate from the µLC-MS analysis, enabling orthogonality, which contributes to the reduction of chemical noise and thus results in improved sensitivity. Typically, the selective-trapping and -delivery approach strategically removes >85% of the matrix peptides and detrimental components, markedly enhancing sensitivity, throughput, and operational robustness, and narrow-window-isolation selected-reaction monitoring further improves the signal-to-noise ratio. In addition, unique LC-hardware setups and flow approaches eliminate gradient shock and achieve effective peak compression, enabling highly sensitive analyses of plasma or tissue samples without band broadening. In this study, the quantification of 10 biotherapeutics and biomarkers in plasma and tissues was employed for method development. As observed, a significant sensitivity gain (up to 25-fold) compared with that of conventional LC-MS was achieved, although the average run time was only 8 min/sample. No appreciable peak deterioration or loss of sensitivity was observed after >1500 injections of tissue and plasma samples. The developed method enabled, for the first time, ultrasensitive LC-MS quantification of low levels of a monoclonal antibody and antigen in a tumor and cardiac troponin I in plasma after brief cardiac ischemia. This strategy is valuable when highly sensitive protein quantification in large sample sets is required, as is often the case in typical biomarker validation and pharmaceutical investigations of antibody therapeutics.

Distinct Functions of Syntaxin-1 in Neuronal Maintenance, Synaptic Vesicle Docking, and Fusion in Mouse Neurons.

UNLABELLED: Neurotransmitter release requires the formation of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complexes by SNARE proteins syntaxin-1 (Stx1), synaptosomal-associated protein 25 (SNAP-25), and synaptobrevin-2 (Syb2). In mammalian systems, loss of SNAP-25 or Syb2 severely impairs neurotransmitter release; however, complete loss of function studies for Stx1 have been elusive due to the functional redundancy between Stx1 isoforms Stx1A and Stx1B and the embryonic lethality of Stx1A/1B double knock-out (DKO) mice. Here, we studied the roles of Stx1 in neuronal maintenance and neurotransmitter release in mice with constitutive or conditional deletion of Stx1B on an Stx1A-null background. Both constitutive and postnatal loss of Stx1 severely compromised neuronal viability in vivo and in vitro, indicating an obligatory role of Stx1 for maintenance of developing and mature neurons. Loss of Munc18-1, a high-affinity binding partner of Stx1, also showed severely impaired neuronal viability, but with a slower time course compared with Stx1A/1B DKO neurons, and exogenous Stx1A or Stx1B expression significantly delayed Munc18-1-dependent lethality. In addition, loss of Stx1 completely abolished fusion-competent vesicles and severely impaired vesicle docking, demonstrating its essential roles in neurotransmission. Putative partial SNARE complex assembly with the SNARE motif mutant Stx1A(AV) (A240V, V244A) was not sufficient to rescue neurotransmission despite full recovery of vesicle docking and neuronal survival. Together, these data suggest that Stx1 has independent functions in neuronal maintenance and neurotransmitter release and complete SNARE complex formation is required for vesicle fusion and priming, whereas partial SNARE complex formation is sufficient for vesicle docking and neuronal maintenance. SIGNIFICANCE STATEMENT: Syntaxin-1 (Stx1) is a component of the synaptic vesicle soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex and is essential for neurotransmission. We present the first detailed loss-of-function characterization of the two Stx1 isoforms in central mammalian neurons. We show that Stx1 is fundamental for maintenance of developing and mature neurons and also for vesicle docking and neurotransmission. We also demonstrate that neuronal maintenance and neurotransmitter release are regulated by Stx1 through independent functions. Furthermore, we show that SNARE complex formation is required for vesicle fusion, whereas partial SNARE complex formation is sufficient for vesicle docking and neuronal maintenance. Therefore, our work provides insights into differential functions of Stx1 in neuronal maintenance and neurotransmission, with the latter explored further into its functions in vesicle docking and fusion.

Borna disease virus-induced neuronal degeneration dependent on host genetic background and prevented by soluble factors.

Infection of newborn rats with Borne disease virus (BDV) results in selective degeneration of granule cell neurons of the dentate gyrus (DG). To study cellular countermechanisms that might prevent this pathology, we screened for rat strains resistant to this BDV-induced neuronal degeneration. To this end, we infected hippocampal slice cultures of different rat strains with BDV and analyzed for the preservation of the DG. Whereas infected cultures of five rat strains, including Lewis (LEW) rats, exhibited a disrupted DG cytoarchitecture, slices of three other rat strains, including Sprague-Dawley (SD), were unaffected. However, efficiency of viral replication was comparable in susceptible and resistant cultures. Moreover, these rat strain-dependent differences in vulnerability were replicated in vivo in neonatally infected LEW and SD rats. Intriguingly, conditioned media from uninfected cultures of both LEW and SD rats could prevent BDV-induced DG damage in infected LEW hippocampal cultures, whereas infection with BDV suppressed the availability of these factors from LEW but not in SD hippocampal cultures. To gain further insights into the genetic basis for this rat strain-dependent susceptibility, we analyzed DG granule cell survival in BDV-infected cultures of hippocampal neurons derived from the F1 and F2 offspring of the crossing of SD and LEW rats. Genome-wide association analysis revealed one resistance locus on chromosome (chr) 6q16 in SD rats and, surprisingly, a locus on chr3q21-23 that was associated with susceptibility. Thus, BDV-induced neuronal degeneration is dependent on the host genetic background and is prevented by soluble protective factors in the disease-resistant SD rat strain.

Syntaxin 1B is important for mouse postnatal survival and proper synaptic function at the mouse neuromuscular junctions.

STX1 is a major neuronal syntaxin protein located at the plasma membrane of the neuronal tissues. Rodent STX1 has two highly similar paralogs, STX1A and STX1B, that are thought to be functionally redundant. Interestingly, some studies have shown that the distribution patterns of STX1A and STX1B at the central and peripheral nervous systems only partially overlapped, implying that there might be differential functions between these paralogs. In the current study, we generated an STX1B knockout (KO) mouse line and studied the impact of STX1B removal in neurons of several brain regions and the neuromuscular junction (NMJ). We found that either complete removal of STX1B or selective removal of it from forebrain excitatory neurons in mice caused premature death. Autaptic hippocampal and striatal cultures derived from STX1B KO mice still maintained efficient neurotransmission compared with neurons from STX1B wild-type and heterozygous mice. Interestingly, examining high-density cerebellar cultures revealed a decrease in the spontaneous GABAergic transmission frequency, which was most likely due to a lower number of neurons in the STX1B KO cultures, suggesting that STX1B is essential for neuronal survival in vitro. Moreover, our study also demonstrated that although STX1B is dispensable for the formation of the mouse NMJ, it is required to maintain the efficiency of neurotransmission at the nerve-muscle synapse.

High Physical Activity is Associated with an Improved Lipid Profile and Resting Heart Rate among Healthy Middle-aged Chinese People.

OBJECTIVE: To investigate the effects of physical activity (PA) on dyslipidemia and elevated resting heart rate (RHR) in a large-scale cross-sectional study in China. METHODS: We recruited community-based individuals who were 40-60 years old using a cluster sampling method. The PA levels of the participants were classified as low, moderate, or high, using the International Physical Activity Questionnaire. Dyslipidemia was defined as the detection of abnormalities in lipid indicators, and 4 lipid parameters were evaluated using fasting blood samples. Multivariate logistic regression analyses were used to evaluate the associations of PA with dyslipidemia and RHR. RESULTS: A total of 10,321 participants (38.88% men) were included in this study. The percentages of individuals with high, moderate, and low PA levels were 46.5%, 43.9%, and 9.6%, respectively. In both men and women, high PA provided odds ratios of 0.88 [95% confidence interval (CI): 0.83, 0.94] for dyslipidemia and 0.82 (95% CI: 0.73, 0.92) for elevated RHR, compared to participants with low PA. CONCLUSION: Our data suggested that substantial health benefits (related to dyslipidemia and elevated RHR) occurred at higher intensity PA, with greater energy consumption, in middle-aged Chinese people, and particularly in men.

Titration of Syntaxin1 in mammalian synapses reveals multiple roles in vesicle docking, priming, and release probability.

Synaptic vesicles undergo sequential steps in preparation for neurotransmitter release. Individual SNARE proteins and the SNARE complex itself have been implicated in these processes. However, discrete effects of SNARE proteins on synaptic function have been difficult to assess using complete loss-of-function approaches. We therefore used a genetic titration technique in cultured mouse hippocampal neurons to evaluate the contribution of the neuronal SNARE protein Syntaxin1 (Stx1) in vesicle docking, priming, and release probability. We generated graded reductions of total Stx1 levels by combining two approaches, namely, endogenous hypomorphic expression of the isoform Stx1B and RNAi-mediated knockdown. Proximity of synaptic vesicles to the active zone was not strongly affected. However, overall release efficiency of affected neurons was severely impaired, as demonstrated by a smaller readily releasable pool size, slower refilling rate of primed vesicles, and lower release probability. Interestingly, dose-response fitting of Stx1 levels against readily releasable pool size and vesicular release probability showed similar Kd (dissociation constant) values at 18% and 19% of wild-type Stx1, with cooperativity estimates of 3.4 and 2.5, respectively. This strongly suggests that priming and vesicle fusion share the same molecular stoichiometry, and are governed by highly related mechanisms.