A PrP EGFR signaling axis controls neural stem cell senescence through modulating cellular energy pathways.

Mis-folding of the prion protein (PrP) is known to cause neurodegenerative disease; however, the native function of this protein remains poorly defined. PrP has been linked with many cellular functions, including cellular proliferation and senescence. It is also known to influence epidermal growth factor receptor (EGFR) signaling, a pathway that is itself linked with both cell growth and senescence. Adult neural stem cells (NSCs) persist at low levels in the brain throughout life and retain the ability to proliferate and differentiate into new neural lineage cells. KO of PrP has previously been shown to reduce NSC proliferative capacity. We used PrP KO and WT NSCs from adult mouse brain to examine the influence of PrP on cellular senescence, EGFR signaling, and the downstream cellular processes. PrP KO NSCs showed decreased cell proliferation and increased senescence in in vitro cultures. Expression of EGFR was decreased in PrP KO NSCs compared with WT NSCs and additional supplementation of EGF was sufficient to reduce senescence. RNA-seq analysis confirmed that significant changes were occurring at the mRNA level within the EGFR signaling pathway and these were associated with reduced expression of mitochondrial components and correspondingly reduced mitochondrial function. Metabolomic analysis of cellular energy pathways showed that blockages were occurring at critical sites for production of energy and biomass, including catabolism of pyruvate. We conclude that, in the absence of PrP, NSC growth pathways are downregulated as a consequence of insufficient energy and growth intermediates.

Perforated peptic ulcer disease in transferred patients is associated with significant increase in length of stay.

BACKGROUND: Perforated peptic ulcer disease (PPUD) has a prevalence of 0.004-0.014% with mortality of 23.5% (Tarasconi et al. in World J Emerg Surg 15(PG-3):3, 2020). In this single center study, we examined the impact associated with patient transfer from outside facilities to our center for definitive surgical intervention (exploratory laparotomy). METHODS: Using EPIC report workbench, we identified 27 patients between 2018 and 2021 undergoing exploratory laparotomy with a concurrent diagnosis of peptic ulcer disease, nine of which were transferred to our institution for care. We queried this population for markers of disease severity including mortality, length of stay, intensive care unit (ICU) length of stay, and readmission rates. Manual chart reviews were performed to examine these outcomes in more detail and identify patients who had been transferred to our facility for surgery from an outside hospital. RESULTS: A total of 27 patients were identified undergoing exploratory laparotomy for definitive treatment of PPUD. The majority of patients queried underwent level A operations, the most urgent level of activation. In our institution, a Level A operation needs to go to the operating room within one hour of arrival to the hospital. Average mortality for this patient population was 14.8%. The readmission rate was 40.1%, and average length of ICU stay post-operatively was 16 days, with 83% of non-transfer patients requiring ICU admission and 100% of transfer patients requiring ICU admission, although this was not found to be statistically significant. Average length of hospital stay was 27 days overall. For non-transfer patients and transfer patients, LOS was 20 days and 41 days, respectively, which was statistically significant by one-sided t-test (p = 0.05). CONCLUSION: Patients transferred for definitive care of PPUD in a population otherwise notable for high mortality and high readmission rates: their average length of stay compared to non-transfer patients was over twice the length, which was statistically significant. Transferred patients also had higher rates of ICU care requirement although this was not statistically significant. Further inquiry to identify modifiable variables to facilitate the care of transferred patients is warranted, especially in the context of improving quality metrics known to enhance patient outcomes, satisfaction, and value.

Strategies for the Management of Patients with Pancreatic Cancer with PARP Inhibitors.

A subset of patients with pancreatic adenocarcinomas (PDAC) harbor mutations that are exploitable in the context of DNA-damage response and repair (DDR) inhibitory strategies. Between 8-18% of PDACs harbor specific mutations in the DDR pathway such as BRCA1/2 mutations, and a higher prevalence exists in high-risk populations (e.g., Ashkenazi Jews). Herein, we will review the current trials and data on the treatment of PDAC patients who harbor such mutations and who appear sensitive to platinum and/or poly ADP ribose polymerase inhibitor (PARPi) based therapies due to a concept known as synthetic lethality. Although this current best-in-class precision treatment shows clinical promise, the specter of resistance limits the extent of therapeutic responses. We therefore also evaluate promising pre-clinical and clinical approaches in the pipeline that may either work with existing therapies to break resistance or work separately with combination therapies against this subset of PDACs.

Pharmacological agents for prevention of pruritus in women undergoing Caesarean delivery with neuraxial morphine: a systematic review and Bayesian network meta-analysis.

BACKGROUND: Neuraxial opioids provide effective analgesia for Caesarean delivery, however, pruritus can be a troubling side-effect. Effective agents to prevent pruritus are needed. Our objective was to perform an updated systematic review and network meta-analysis to provide clinicians with a comparison of relative efficacy of available interventions to reduce the incidence of pruritus, induced by either intrathecal or epidural single-shot morphine, in women undergoing Caesarean delivery. METHODS: Databases systematically searched (up to January 2022) included PubMed MEDLINE, Web of Science, EBSCO CINAHL, Embase, LILACS, and two Cochrane databases. We included randomised, controlled trials involving adult female patients undergoing Caesarean delivery. We pooled trials comparing interventions used for preventing pruritus after Caesarean delivery and performed a Bayesian model network meta-analysis. RESULTS: The final primary network included data from comparisons of 14 distinct interventions (including placebo) used to reduce the incidence of pruritus in 6185 participants. We judged five interventions to be 'definitely superior' to placebo: propofol, opioid agonist-antagonists (neuraxial), opioid antagonists, opioid agonist-antagonists (systemic), and serotonin antagonists. For the network evaluating the incidence of severe pruritus (warranting additional therapeutic treatment of pruritus), data were available for 14 interventions (including placebo) in 4489 patients. For this outcome, we judged three interventions to be 'definitely superior' to placebo: dopamine antagonists (neuraxial) and systemic and neuraxial opioid agonist-antagonists. CONCLUSION: Our analysis found several interventions to be effective in reducing the incidence of pruritus. Although sub-hypnotic doses of propofol appear to have an antipruritic effect, replication of this finding and further investigation of optimal dosing are warranted. SYSTEMATIC REVIEW PROTOCOL: PROSPERO (CRD42022367058).

Paediatric pancreatic trauma in North Queensland: a 10-year retrospective review.

PURPOSE: To establish the incidence of pancreatic trauma in North Queensland to the region's only tertiary paediatric referral centre, and to determine the patient's outcomes based on their management. METHODS: A single centre, retrospective cohort study of patients < 18 years with pancreatic trauma from 2009 to 2020 was performed. There were no exclusion criteria. RESULTS: Between 2009 and 2020 there were 145 intra-abdominal trauma cases, 37% from motor vehicle accidents (MVA), 18.6% motorbike or quadbike, and 12.4% bicycle or scooter accidents. There were 19 cases of pancreatic trauma (13%), all from blunt trauma and with associated injuries. There were 5 AAST grade I, 3 grade II, 3 grade III, 3 grade IV injuries, and 4 with traumatic pancreatitis. Twelve patients were managed conservatively, 2 were managed operatively for another reason, and 5 were managed operatively for the pancreatic injury. Only 1 patient with a high grade AAST injury was successfully managed non-operatively. Complications included pancreatic pseudocyst (n = 4/19; 3 post-op), pancreatitis (n = 2/19; 1 post op), and post-operative pancreatic fistula (POPF) (n = 1/19). CONCLUSION: Due to North Queensland's geography, diagnosis and management of traumatic pancreatic injury is often delayed. Pancreatic injuries requiring surgery are at high risk for complications, prolonged length of stay, and further interventions.

Resveratrol increases tear production and ocular pain after corneal abrasion in male, but not female, rats using a photorefractive keratectomy model.

Photorefractive keratectomy (PRK) is an alternative to LASIK and can cause intense acute pain that is often not relieved by standard treatments. To assess potential therapeutics for this type of acute pain, appropriate preclinical models are needed. We describe a preclinical corneal abrasion rat model that simulates the initial stages of PRK surgery and demonstrates similar pain and tear dysfunction as seen clinically. We used both behavioral and homeostatic assays to determine the therapeutic potential of resveratrol on pain and tear production. Studies were conducted in male and female Sprague-Dawley rats. Heptanol was applied to one eye and the superficial corneal epithelium was removed, mimicking the abrasion used in PRK. Spontaneous pain was assessed with orbital tightening (OT) scores for 7 days. Topical resveratrol increased OT scores sex-specifically in abraded males, but not females, at 72 h and 1 week after abrasion. Resveratrol increased tear production in abraded males, with no effect in abraded females. There was no correlation between OT score at 1 week and tear production measurements, demonstrating no relationship between spontaneous ocular pain and tear dysfunction in this model. These findings demonstrate the usefulness of our corneal abrasion preclinical PRK model for the assessment of ocular pain therapeutics and indicate that topical resveratrol may not be useful for managing PRK-induced pain.

Innate immune responses after stimulation with Toll-like receptor agonists in ex vivo microglial cultures and an in vivo model using mice with reduced microglia.

BACKGROUND: Past experiments studying innate immunity in the central nervous system (CNS) utilized microglia obtained from neonatal mouse brain, which differ developmentally from adult microglia. These differences might impact our current understanding of the role of microglia in CNS development, function, and disease. METHODS: Cytokine protein secretion was compared in ex vivo P3 and adult microglial cultures after exposure to agonists for three different toll-like receptors (TLR4, lipopolysaccharide [LPS]; TLR7, imiquimod [IMQ]; and TLR9, CpG Oligodeoxynucleotide [CpG-ODN] 1585). In addition, changes in inflammatory gene expression in ex vivo adult microglia in response to the TLR agonists was assessed. Furthermore, in vivo experiments evaluated changes in gene expression associated with inflammation and TLR signaling in brains of mice with or without treatment with PLX5622 to reduce microglia. RESULTS: Ex vivo adult and P3 microglia increased cytokine secretion when exposed to TLR4 agonist LPS and to TLR7 agonist IMQ. However, adult microglia decreased expression of numerous genes after exposure to TLR 9 agonist CpG-ODN 1585. In contrast, in vivo studies indicated a core group of inflammatory and TLR signaling genes increased when each of the TLR agonists was introduced into the CNS. Reducing microglia in the brain led to decreased expression of various inflammatory and TLR signaling genes. Mice with reduced microglia showed extreme impairment in upregulation of genes after exposure to TLR7 agonist IMQ. CONCLUSIONS: Cultured adult microglia were more reactive than P3 microglia to LPS or IMQ exposure. In vivo results indicated microglial influences on neuroinflammation were agonist specific, with responses to TLR7 agonist IMQ more dysregulated in mice with reduced microglia. Thus, TLR7-mediated innate immune responses in the CNS appeared more dependent on the presence of microglia. Furthermore, partial responses to TLR4 and TLR9 agonists in mice with reduced microglia suggested other cell types in the CNS can compensate for their absence.

Takotsubo cardiomyopathy complicating acute pancreatitis: a case report.

BACKGROUND: Acute pancreatitis as a trigger of Takotsubo cardiomyopathy has been infrequently described in the literature. Misdiagnosis of this phenomenon can often occur due to overlap in symptomology, particularly in those outside of the usual patient demographic. CASE PRESENTATION: A 27-year-old man with a history of alcohol abuse presented with epigastric and chest pain. Electrocardiography showed ischemic changes, and laboratory workup revealed elevated lipase and troponin. He was diagnosed with acute pancreatitis and managed presumptively as acute coronary syndrome. Subsequent coronary angiography was negative for obstructive coronary artery disease, and left ventriculography demonstrated basal hyperkinesis and apical akinesis, characteristic of Takotsubo cardiomyopathy. CONCLUSIONS: Takotsubo cardiomyopathy is a rare complication of acute pancreatitis. Increased awareness of this phenomenon is required to prevent delays in diagnosis and avoid unnecessary interventions and complications.

Cost-effectiveness of photobiomodulation therapy for the prevention and management of cancer treatment toxicities: a systematic review.

PURPOSE: To identify and summarize the evidence on the cost-effectiveness of photobiomodulation (PBM) therapy for the prevention and treatment of cancer treatment-related toxicities. METHODS: This systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement (PRISMA) and Meta-analysis Of Observational Studies in Epidemiology (MOOSE). Scopus, MEDLINE/PubMed, and Embase were searched electronically. RESULTS: A total of 1490 studies were identified, and after a two-step review, 4 articles met the inclusion criteria. The included studies analyzed the cost-effectiveness of PBM therapy used in the context of lymphedema for breast cancer and oral mucositis (OM) induced by chemotherapy and radiotherapy. Better outcomes were associated with PBM therapy. The incremental cost-effectiveness ratio ranged from 3050.75 USD to 5592.10 USD per grade 3-4 OM case prevented. PBM therapy cost 21.47 USD per percentage point reduction in lymphedema in comparison with 80.51 USD for manual lymph drainage and physical therapy. CONCLUSION: There is limited evidence that PBM therapy is cost-effective in the prevention and treatment of specific cancer treatment-related toxicities, namely, OM and breast cancer-related lymphedema. Studies may have underreported the benefits due to a lack of a comprehensive cost evaluation. This suggests a wider acceptance of PBM therapy at cancer treatment centers, which has thus far been limited by the number of robust clinical studies that demonstrate cost-effectiveness for the prevention and treatment of toxicities.

Photobiomodulation effects on head and neck squamous cell carcinoma (HNSCC) in an orthotopic animal model.

BACKGROUND: Photobiomodulation (PBM) has shown efficacy in preventing and treating cancer therapy-induced mucositis and dermatitis. However, there is contradictory information regarding the effect of PBM on (pre)malignant cells, which has led to questions regarding the safety of this technique. We address this issue using an orthotopic mouse model (Cal-33) with human squamous cell carcinoma of the oral cavity. METHODS: Mice with actively growing orthotopic Cal-33 head and neck carcinoma tumors were divided into 4 groups: control, PBM only, radiation therapy (RT) only, and PBM + RT. We performed three experiments: (1) PBM at 660 nm, 18.4 J/cm2, and 5 RT × 4 Gy doses delivered daily; (2) PBM at 660 nm, 18.4 J/cm2, and 1 × 15 Gy RT; and (3) PBM at 660 nm + 850 nm, 45 mW/cm2, 3.4 J/cm2, and 1 × 15 Gy RT. Mice were weighed daily and tumor volumes were evaluated by IVIS. Survival time was also evaluated. RESULTS: Animals treated with RT survived significantly longer and had significantly smaller tumor volume when compared with the control and PBM-only treatment groups. No significant differences were noted between the RT alone and PBM + RT groups in any of the experiments. CONCLUSION: Our results suggest that PBM at the utilized parameters does not provide protection to the tumor from the killing effects of RT.

Wind Turbine Gearbox Condition Monitoring Based on Class of Support Vector Regression Models and Residual Analysis.

The intelligent condition monitoring of wind turbines reduces their downtime and increases reliability. In this manuscript, a feature selection-based methodology that essentially works on regression models is used for identifying faulty scenarios. Supervisory control and data acquisition (SCADA) data with 1009 samples from one year and one month before failure are considered. Gearbox oil and bearing temperatures are treated as target variables with all the other variables used for the prediction model. Neighborhood component analysis (NCA) as a feature selection technique is employed to select the best features and prediction performance for several machine learning regression models is assessed. The results reveal that twin support vector regression (99.91%) and decision trees (98.74%) yield the highest accuracy for gearbox oil and bearing temperatures respectively. It is observed that NCA increases the accuracy and thus reliability of the condition monitoring system. Furthermore, the residuals from the class of support vector regression (SVR) models are tested from a statistical point of view. Diebold-Mariano and Durbin-Watson tests are carried out to establish the robustness of the tested models.

Interlaboratory Comparison of Hydrogen-Deuterium Exchange Mass Spectrometry Measurements of the Fab Fragment of NISTmAb.

Hydrogen-deuterium exchange mass spectrometry (HDX-MS) is an established, powerful tool for investigating protein-ligand interactions, protein folding, and protein dynamics. However, HDX-MS is still an emergent tool for quality control of biopharmaceuticals and for establishing dynamic similarity between a biosimilar and an innovator therapeutic. Because industry will conduct quality control and similarity measurements over a product lifetime and in multiple locations, an understanding of HDX-MS reproducibility is critical. To determine the reproducibility of continuous-labeling, bottom-up HDX-MS measurements, the present interlaboratory comparison project evaluated deuterium uptake data from the Fab fragment of NISTmAb reference material (PDB: 5K8A ) from 15 laboratories. Laboratories reported ∼89 800 centroid measurements for 430 proteolytic peptide sequences of the Fab fragment (∼78 900 centroids), giving ∼100% coverage, and ∼10 900 centroid measurements for 77 peptide sequences of the Fc fragment. Nearly half of peptide sequences are unique to the reporting laboratory, and only two sequences are reported by all laboratories. The majority of the laboratories (87%) exhibited centroid mass laboratory repeatability precisions of ⟨ sLab⟩ ≤ (0.15 ± 0.01) Da (1σx̅). All laboratories achieved ⟨sLab⟩ ≤ 0.4 Da. For immersions of protein at THDX = (3.6 to 25) °C and for D2O exchange times of tHDX = (30 s to 4 h) the reproducibility of back-exchange corrected, deuterium uptake measurements for the 15 laboratories is σreproducibility15 Laboratories( tHDX) = (9.0 ± 0.9) % (1σ). A nine laboratory cohort that immersed samples at THDX = 25 °C exhibited reproducibility of σreproducibility25C cohort( tHDX) = (6.5 ± 0.6) % for back-exchange corrected, deuterium uptake measurements.

Microglia Are Critical in Host Defense against Prion Disease.

Microglial cells in the central nervous system play important roles in neurodevelopment and resistance to infection, yet microglia can become neurotoxic under some conditions. An early event during prion infection is the activation of microglia and astrocytes in the brain prior to damage or death of neurons. Previous prion disease studies using two different strategies to manipulate signaling through the microglial receptor CSF-1R reported contrary effects on survival from prion disease. However, in these studies, reductions of microglial numbers and function were variable, thus confounding interpretation of the results. In the present work, we used oral treatment with a potent inhibitor of CSF-1R, PLX5622, to eliminate 78 to 90% of microglia from cortex early during the course of prion infection. Oral drug treatment early after infection with the RML scrapie strain significantly accelerated vacuolation, astrogliosis, and deposition of disease-associated prion protein. Furthermore, drug-treated mice had advanced clinical disease requiring euthanasia 31 days earlier than untreated control mice. Similarly, PLX5622 treatment during the preclinical phase at 80 days postinfection with RML scrapie also accelerated disease and resulted in euthanasia of mice 33 days earlier than infected controls. PLX5622 also accelerated clinical disease after infection with scrapie strains ME7 and 22L. Thus, microglia are critical in host defense during prion disease. The early accumulation of PrPSc in the absence of microglia suggested that microglia may function by clearing PrPSc, resulting in longer survival.IMPORTANCE Microglia contribute to many aspects of health and disease. When activated, microglia can be beneficial by repairing damage in the central nervous system (CNS) or they can turn harmful by becoming neurotoxic. In prion and prionlike diseases, the involvement of microglia in disease is unclear. Previous studies suggest that microglia can either speed up or slow down disease. In this study, we infected mice with prions and depleted microglia from the brains of mice using PLX5622, an effective CSF-1R tyrosine kinase inhibitor. Microglia were markedly reduced in brains, and prion disease was accelerated, so that mice needed to be euthanized 20 to 33 days earlier than infected control mice due to advanced clinical disease. Similar results occurred when mice were treated with PLX5622 at 80 days after infection, which was just prior to the start of clinical signs. Thus, microglia are important for removing prions, and the disease is faster when microglia are depleted.

Prion Strain Differences in Accumulation of PrPSc on Neurons and Glia Are Associated with Similar Expression Profiles of Neuroinflammatory Genes: Comparison of Three Prion Strains.

Misfolding and aggregation of host proteins are important features of the pathogenesis of neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, frontotemporal dementia and prion diseases. In all these diseases, the misfolded protein increases in amount by a mechanism involving seeded polymerization. In prion diseases, host prion protein is misfolded to form a pathogenic protease-resistant form, PrPSc, which accumulates in neurons, astroglia and microglia in the CNS. Here using dual-staining immunohistochemistry, we compared the cell specificity of PrPSc accumulation at early preclinical times post-infection using three mouse scrapie strains that differ in brain regional pathology. PrPSc from each strain had a different pattern of cell specificity. Strain 22L was mainly associated with astroglia, whereas strain ME7 was mainly associated with neurons and neuropil. In thalamus and cortex, strain RML was similar to 22L, but in substantia nigra, RML was similar to ME7. Expression of 90 genes involved in neuroinflammation was studied quantitatively using mRNA from thalamus at preclinical times. Surprisingly, despite the cellular differences in PrPSc accumulation, the pattern of upregulated genes was similar for all three strains, and the small differences observed correlated with variations in the early disease tempo. Gene upregulation correlated with activation of both astroglia and microglia detected in early disease prior to vacuolar pathology or clinical signs. Interestingly, the profile of upregulated genes in scrapie differed markedly from that seen in two acute viral CNS diseases (LaCrosse virus and BE polytropic Friend retrovirus) that had reactive gliosis at levels similar to our prion-infected mice.

Non-small cell lung cancer clinical trials requiring biopsies with biomarker-specific results for enrollment provide unique challenges.

BACKGROUND: Clinical trials in lung cancer increasingly require patients to provide fresh tumor tissue as a prerequisite to enrollment. The effects of this requirement on enrollment rates, enrollment durations, and patient selection have not been fully elucidated. METHODS: The authors retrospectively reviewed data generated by patients who consented to 1 or more interventional lung cancer clinical trials at the University of California-Los Angeles Jonsson Comprehensive Cancer Center between January 2013 and December 2014. Trials were considered to require a biopsy when enrollment was conditional on the procurement of tissue without intervening therapy between procurement and enrollment. RESULTS: In total, 311 patients underwent 368 screening incidents for 1 or more of 19 trials. Trials that required a new biopsy had a longer median screening duration (34 vs 14 days) than trials that did not require a biopsy (P < .001). Trials that required a biopsy had a greater screen failure rate (49.1% vs 26.5%; P < .001), which was largely driven by patients who did not undergo the required biopsy or lacked the required biomarker. Worsening performance status led to the majority of screen failures (56.5%) among biomarker-eligible patients. CONCLUSIONS: Although the scientific benefits of obtaining a new biopsy and requiring specific results for trial enrollment are clear, these requirements lead to a lengthening of the screening period, which, in some patients, is associated with clinical decline before enrollment. Implications for the interpretation of data from studies of this design should be explored. Cancer 2017;123:4800-7. © 2017 American Cancer Society.

Statins are ineffective at reducing neuroinflammation or prolonging survival in scrapie-infected mice.

Neuroinflammation is a prominent component of several neurodegenerative diseases, including multiple sclerosis, Alzheimer's disease, Parkinson's disease, tauopathies, amyotrophic lateral sclerosis and prion diseases. In such conditions, the ability to decrease neuroinflammation by drug therapy may influence disease progression. Statins have been used to treat hyperlipidemia as well as reduce neuroinflammation and oxidative stress in various tissues. In previous studies, treatment of scrapie-infected mice with the type 1 statins, simvastatin or pravastatin, showed a small beneficial effect on survival time. In the current study, to increase the effectiveness of statin therapy, we treated infected mice with atorvastatin, a type 2 statin that has improved pharmacokinetics over many type 1 statins. Treatments with either simvastatin or pravastatin were tested for comparison. We evaluated scrapie-infected mice for protease-resistant PrP (PrPres) accumulation, gliosis, neuroinflammation and time until advanced clinical disease requiring euthanasia. All three statin treatments reduced total serum cholesterol ≥40 % in mice. However, gliosis and PrPres deposition were similar in statin-treated and untreated infected mice. Time to euthanasia due to advanced clinical signs was not changed in statin-treated mice relative to untreated mice, a finding at odds with previous reports. Expression of 84 inflammatory genes involved in neuroinflammation was also quantitated. Seven genes were reduced by pravastatin, and one gene was reduced by atorvastatin. In contrast, simvastatin therapy did not reduce any of the tested genes, but did slightly increase the expression of Ccl2 and Cxcl13. Our studies indicate that none of the three statins tested were effective in reducing scrapie-induced neuroinflammation or neuropathogenesis.

Knockout of fractalkine receptor Cx3cr1 does not alter disease or microglial activation in prion-infected mice.

Microglial activation is a hallmark of the neuroimmunological response to Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis and prion disease. The CX3C chemokine axis consists of fractalkine (CX3CL1) and its receptor (CX3CR1); these are expressed by neurons and microglia respectively, and are known to modulate microglial activation. In prion-infected mice, both Cx3cr1 and Cx3cl1 are altered, suggesting a role in disease. To investigate the influence of CX3C axis signalling on prion disease, we infected Cx3cr1 knockout (Cx3cr1-KO) and control mice with scrapie strains 22L and RML. Deletion of Cx3cr1 had no effect on development of clinical signs or disease incubation period. In addition, comparison of brain tissue from Cx3cr1-KO and control mice revealed no significant differences in cytokine levels, spongiosis, deposition of disease-associated prion protein or microglial activation. Thus, microglial activation during prion infection did not require CX3C axis signalling.

Prion infection of mouse brain reveals multiple new upregulated genes involved in neuroinflammation or signal transduction.

UNLABELLED: Gliosis is often a preclinical pathological finding in neurodegenerative diseases, including prion diseases, but the mechanisms facilitating gliosis and neuronal damage in these diseases are not understood. To expand our knowledge of the neuroinflammatory response in prion diseases, we assessed the expression of key genes and proteins involved in the inflammatory response and signal transduction in mouse brain at various times after scrapie infection. In brains of scrapie-infected mice at pre- and postclinical stages, we identified 15 previously unreported differentially expressed genes related to inflammation or activation of the STAT signal transduction pathway. Levels for the majority of differentially expressed genes increased with time postinfection. In quantitative immunoblotting experiments of STAT proteins, STAT1α, phosphorylated-STAT1α (pSTAT1α), and pSTAT3 were increased between 94 and 131 days postinfection (p.i.) in brains of mice infected with strain 22L. Furthermore, a select group of STAT-associated genes was increased preclinically during scrapie infection, suggesting early activation of the STAT signal transduction pathway. Comparison of inflammatory markers between mice infected with scrapie strains 22L and RML indicated that the inflammatory responses and gene expression profiles in the brains were strikingly similar, even though these scrapie strains infect different brain regions. The endogenous interleukin-1 receptor antagonist (IL-1Ra), an inflammatory marker, was newly identified as increasing preclinically in our model and therefore might influence scrapie pathogenesis in vivo. However, in IL-1Ra-deficient or overexpressor transgenic mice inoculated with scrapie, neither loss nor overexpression of IL-1Ra demonstrated any observable effect on gliosis, protease-resistant prion protein (PrPres) formation, disease tempo, pathology, or expression of the inflammatory genes analyzed. IMPORTANCE: Prion infection leads to PrPres deposition, gliosis, and neuroinflammation in the central nervous system before signs of clinical illness. Using a scrapie mouse model of prion disease to assess various time points postinoculation, we identified 15 unreported genes that were increased in the brains of scrapie-infected mice and were associated with inflammation and/or JAK-STAT activation. Comparison of mice infected with two scrapie strains (22L and RML), which have dissimilar neuropathologies, indicated that the inflammatory responses and gene expression profiles in the brains were similar. Genes that increased prior to clinical signs might be involved in controlling scrapie infection or in facilitating damage to host tissues. We tested the possible role of the endogenous IL-1Ra, which was increased at 70 days p.i. In scrapie-infected mice deficient in or overexpressing IL-1Ra, there was no observable effect on gliosis, PrPres formation, disease tempo, pathology, or expression of inflammatory genes analyzed.

Multiple Posttranslational Modifications of Leptospira biflexa Proteins as Revealed by Proteomic Analysis.

The saprophyte Leptospira biflexa is an excellent model for studying the physiology of the medically important Leptospira genus, the pathogenic members of which are more recalcitrant to genetic manipulation and have significantly slower in vitro growth. However, relatively little is known regarding the proteome of L. biflexa, limiting its utility as a model for some studies. Therefore, we have generated a proteomic map of both soluble and membrane-associated proteins of L. biflexa during exponential growth and in stationary phase. Using these data, we identified abundantly produced proteins in each cellular fraction and quantified the transcript levels from a subset of these genes using quantitative reverse transcription-PCR (RT-PCR). These proteins should prove useful as cellular markers and as controls for gene expression studies. We also observed a significant number of L. biflexa membrane-associated proteins with multiple isoforms, each having unique isoelectric focusing points. L. biflexa cell lysates were examined for several posttranslational modifications suggested by the protein patterns. Methylation and acetylation of lysine residues were predominately observed in the proteins of the membrane-associated fraction, while phosphorylation was detected mainly among soluble proteins. These three posttranslational modification systems appear to be conserved between the free-living species L. biflexa and the pathogenic species Leptospira interrogans, suggesting an important physiological advantage despite the varied life cycles of the different species.