The Role of Interchain Heterodisulfide Formation in Activation of the Human Common β and Mouse βIL-3 Receptors

The cytokines, interleukin-3 (IL-3), interleukin-5 (IL-5), and granulocyte-macrophage colony-stimulating factor (GM-CSF), exhibit overlapping activities in the regulation of hematopoietic cells. In humans, the common β (βc) receptor is shared by the three cytokines and functions together with cytokine-specific α subunits in signaling. A widely accepted hypothesis is that receptor activation requires heterodisulfide formation between the domain 1 D-E loop disulfide in human βc (hβc) and unidentified cysteine residues in the N-terminal domains of the α receptors. Since the development of this hypothesis, new data have been obtained showing that domain 1 of hβc is part of the cytokine binding epitope of this receptor and that an IL-3Rα isoform lacking the N-terminal Ig-like domain (the “SP2” isoform) is competent for signaling. We therefore investigated whether distortion of the domain 1-domain 4 ligand-binding epitope in hβc and the related mouse receptor, β_IL-3, could account for the loss of receptor signaling when the domain 1 D-E loop disulfide is disrupted. Indeed, mutation of the disulfide in hβc led to both a complete loss of high affinity binding with the human IL-3Rα SP2 isoform and of downstream signaling. Mutation of the orthologous residues in the mouse IL-3-specific receptor, β_IL-3, not only precluded direct binding of mouse IL-3 but also resulted in complete loss of high affinity binding and signaling with the mouse IL-3Rα SP2 isoform. Our data are most consistent with a role for the domain 1 D-E loop disulfide of hβc and β_IL-3 in maintaining the precise positions of ligand-binding residues necessary for normal high affinity binding and signaling.     

Treatment of Nocturnal Asthma: the Role of Sustained-Release Theophylline and Oral β-2-Mimetics

In two double-blind, multiple-dose cross-over studies the therapeutic effects of SR theophylline preparations given once each night (mean 11.2mg/kg per day) versus twice daily in equal doses (mean 10.3 mg/kg per day) (study I) and SR-terbutaline in equal doses (mean 0.25 mg/kg per day) versus SR theophylline in unequally divided daily doses (mean 5.3 mg/kg morning dose, 10.6 mg/kg evening dose) study II) were compared in 19 patients with nocturnal asthma. At the end of each treatment period drug serum concentrations and PEFR were measured every 2 hr over a 24-hr period. With the twice-daily, equally divided regimen, serum theophylline concentrations were lower at night than during the day (mean 9.4 ±0.9 versus 11.3± 1.0mg/l). With the single evening administration, serum theophylline concentrations were considerably higher at night (C_max16.3 ±1.4 mg/1) and the circadian variation of PEFR was significantly reduced. PEFR was higher during night and early morning (283 ±14 versus 217 ± 11 l/min, P< 0.005). During daytime in study II, PEFR values were slightly higher with theophylline than terbutaline. There was no significant difference in peak flow between either treatment during the night and early morning. However, additional use of inhaled β-2-mimetics because of asthmatic attacks occurred more often during terbutaline (79 times in 8/10 patients) than theophylline treatment (29 times in 5/10 patients). Symptom scores, number of attacks and side-effects clearly favor the theophylline regimen. We conclude that for patients with nocturnal asthma a once-nightly dose of SR theophylline can be sufficient for stabilization of the airways.     

The Role of Viral Infection in Pest Control: A Mathematical Study

In this paper, we propose a mathematical model of viral infection in pest control. As the viral infection induces host lysis which releases more virus into the environment, on the average ‘κ’ viruses per host, κ∈(1,∞), so the ‘virus replication parameter’ is chosen as the main parameter on which the dynamics of the infection depends. There exists a threshold value κ ₀ beyond which the infection persists in the system. Still for increasing the value of κ, the endemic equilibrium bifurcates towards a periodic solution, which essentially indicates that the viral pesticide has a density-dependent ‘numerical response’ component to its action. Investigation also includes the dependence of the process on predation of natural enemy into the system. A concluding discussion with numerical simulation of the model is also presented.     

The Role of β-Hydroxypropionate in Ethylene Biosynthesis

To search precursors of ethylene in banana fruits, ethylene formation from acetate-2-¹⁴C and fumarate-2,3-¹⁴C by banana slices was studied. Ethylene-¹⁴C formation from acetate-2-^l4C was reduced by the addition of malonate or β-hydroxypropionate, and it was enhanced in a sealed chamber in comparison with the case in an aeration chamber. No label of fumarate-2,3-¹⁴C was incorporated into ethylene.

From these facts it was suggested that acetate-2-¹⁴C was incorporated into ethylene via malonate and β-hydroxypropionate. Participation of fumarate in ethylene biosynthesis of banana fruits was ruled out. β-Hydroxypropionate was postulated as an effective precursor of ethylene formation from acetate-2-^l4C.     

The Role of External Irradiation in the Treatment of Transitional Cell Carcinoma of the Bladder—A Review of Fifty Cases

Of 100 patients with carcinoma of the bladder seen in the Section of Therapeutic Radiology, University of California, San Francisco, between 1957 and 1962, 59 were accepted for radiation treatment. Fifty had transitional cell carcinoma and were treated with supervolt therapy (1 mev or cobalt-60).Two types of tumors were again found suitable for external irradiation: Papillary carcinomas Grades II and III, as long as they have not, or at least have not massively, invaded muscle; and undifferentiated carcinomas, Grade IV, regardless of degree of extension through the pelvis. The former type, if single, is treated by irradiation for the first recurrence after one attempt with radical transurethral resection. In the presence of multiple lesions at the first examination, radiation therapy is given immediately. The latter type is treated by radiation therapy without any attempt at surgical removal.Of 37 patients, Stages A to C, treated more than three years ago, 14 (38 per cent) lived more than three years and eight (22 per cent) had no cystoscopic or clinical signs of active disease and had normal bladder function. Of 23 patients treated more than five years ago, eight were alive after five years (35 per cent) and four (17 per cent) remained controlled by radiation therapy alone, with normal bladder function.No major complications were observed. In particular, no fibrosis of the bladder occurred. Doses ranged from 5,000 r in five and a half weeks to 6,000 r in seven weeks.A close cooperation between urologic surgeons and radiotherapists during recent years permits long-range treatment planning from the time of diagnosis, which is essential in the effective therapy of carcinoma of the bladder.     

MENTAL DISORDERS OF THE AGED—The Role of the State Hospital in the Treatment; Report of a Pilot Study

The number of patients age 65 and over at the Agnews State Hospital now constitutes over one-third of the resident population. The geriatric population is increasing in all California state hospitals.Because this is a relatively new area of concern for the psychiatric institution, the role of the state hospital in the care of the aged is not yet clearly defined.A pilot study of admissions in this age group committed from one county during a 12-month period was undertaken, with an attempt made to evaluate the suitability of the patient for commitment, as well as special problems in admission, treatment during hospitalization, and release from the hospital. The study indicated 42 per cent of persons admitted were considered unsuitable for commitment. Physical illness was found to be a major factor in precipitating admission and a predominating factor in the treatment program after admission. Almost 40 per cent of the patients died within a year after admission.     

Changes in the Prevalence,Treatment and Control of Hypertension in Germany? A Clinical-Epidemiological Study of 50.000 Primary Care Patients

Introduction

Medical societies have developed guidelines for the detection, treatment and control of hypertension (HTN). Our analysis assessed the extent to which such guidelines were implemented in Germany in 2003 and 2001.

Methods

Using standardized clinical diagnostic and treatment appraisal forms, blood pressure levels and patient questionnaires for 55,518 participants from the cross-sectional Targets and Essential Data for Commitment of Treatment (DETECT) study (2003) were analyzed. Physician’s diagnosis of hypertension (HTN_doc) was defined as coding hypertension in the clinical appraisal questionnaire. Alternative definitions used were physician’s diagnosis or the patient’s self-reported diagnosis of hypertension (HTN_doc,pat), physician’s or patient’s self-reported diagnosis or a BP measurement with a systolic BP≥140 mmHg and/or a diastolic BP≥90 (HTN_doc,pat,bp) and diagnosis according to the National Health and Nutrition Examination Survey (HTN_NHANES). The results were compared with the similar German HYDRA study to examine whether changes had occurred in diagnosis, treatment and adequate blood pressure control (BP below 140/90 mmHg) since 2001. Factors associated with pharmacotherapy and control were determined.

Results

The overall prevalence rate for hypertension was 35.5% according to HTN_doc and 56.0% according to NHANES criteria. Among those defined by NHANES criteria, treatment and control rates were 56.0% and 20.3% in 2003, and these rates had improved from 55.3% and 18.0% in 2001. Significant predictors of receiving antihypertensive medication were: increasing age, female sex, obesity, previous myocardial infarction and the prevalence of comorbid conditions such as coronary heart disease (CHD), hyperlipidemia and diabetes mellitus (DM). Significant positive predictors of adequate blood pressure control were CHD and antihypertensive medication. Inadequate control was associated with increasing age, male sex and obesity.

Conclusions

Rates of treated and controlled hypertension according to NHANES criteria in DETECT remained low between 2001 and 2003, although there was some minor improvement.     

A Potential Link between the C5a Receptor 1 and the β1-Adrenoreceptor in the Mouse Heart

Purpose

Inflammation may contribute to the pathogenesis of specific cardiovascular diseases, but it is uncertain if mediators released during the inflammatory process will affect the continued efficacy of drugs used to treat clinical signs of the cardiac disease. We investigated the role of the complement 5a receptor 1 (C5aR1/CD88) in the cardiac response to inflammation or atenolol, and the effect of C5aR1 deletion in control of baseline heart rate in an anesthetized mouse model.

Methods

An initial study showed that PMX53, an antagonist of C5aR1 in normal C57BL6/J (wild type, WT) mice reduced heart rate (HR) and appeared to have a protective effect on the heart following induced sepsis. C5aR1 knockout (CD88-/-) mice had a lower HR than wild type mice, even during sham surgery. A model to assess heart rate variability (HRV) in anesthetized mice was developed to assess the effects of inhibiting the β₁-adrenoreceptor (β₁-AR) in a randomized crossover study design.

Results

HR and LF Norm were constitutively lower and SDNN and HF Norm constitutively higher in the CD88-/- compared with WT mice (P< 0.001 for all outcomes). Administration of atenolol (2.5 mg/kg) reduced the HR and increased HRV (P< 0.05, respectively) in the wild type but not in the CD88-/- mice. There was no shift of the sympathovagal balance post-atenolol in either strains of mice (P> 0.05), except for the reduced LF/HF (Lower frequency/High frequency) ratio (P< 0.05) at 60 min post-atenolol, suggesting increased parasympathetic tone of the heart due to the effect of atenolol administration. The HR of the WT mice were lower post atenolol compared to the CD88-/- mice (P = 0.001) but the HRV of CD88-/- mice were significantly increased (P< 0.05), compared with WT mice.

Conclusion

Knockout of the C5aR1 attenuated the effect of β₁-AR in the heart, suggesting an association between the β₁-AR and C5aR1, although further investigation is required to determine if this is a direct or causal association.     

Targeting of β-Arrestin2 to the Centrosome and Primary Cilium: Role in Cell Proliferation Control

Background

The primary cilium is a sensory organelle generated from the centrosome in quiescent cells and found at the surface of most cell types, from where it controls important physiological processes. Specific sets of membrane proteins involved in sensing the extracellular milieu are concentrated within cilia, including G protein coupled receptors (GPCRs). Most GPCRs are regulated by β-arrestins, βarr1 and βarr2, which control both their signalling and endocytosis, suggesting that βarrs may also function at primary cilium.

Methodology/Principal Findings

In cycling cells, βarr2 was observed at the centrosome, at the proximal region of the centrioles, in a microtubule independent manner. However, βarr2 did not appear to be involved in classical centrosome-associated functions. In quiescent cells, both in vitro and in vivo, βarr2 was found at the basal body and axoneme of primary cilia. Interestingly, βarr2 was found to interact and colocalize with 14-3-3 proteins and Kif3A, two proteins known to be involved in ciliogenesis and intraciliary transport. In addition, as suggested for other centrosome or cilia-associated proteins, βarrs appear to control cell cycle progression. Indeed, cells lacking βarr2 were unable to properly respond to serum starvation and formed less primary cilia in these conditions.

Conclusions/Significance

Our results show that βarr2 is localized to the centrosome in cycling cells and to the primary cilium in quiescent cells, a feature shared with other proteins known to be involved in ciliogenesis or primary cilium function. Within cilia, βarr2 may participate in the signaling of cilia-associated GPCRs and, therefore, in the sensory functions of this cell “antenna”.     

Brucella Cyclic β-1,2-Glucan Plays a Critical Role in the Induction of Splenomegaly in Mice

Brucella, the etiological agent of animal and human brucellosis, is a bacterium with the capacity to modulate the inflammatory response. Cyclic β-1,2-glucan (CβG) is a virulence factor key for the pathogenesis of Brucella as it is involved in the intracellular life cycle of the bacteria. Using comparative studies with different CβG mutants of Brucella, cgs (CβG synthase), cgt (CβG transporter) and cgm (CβG modifier), we have identified different roles for this polysaccharide in Brucella. While anionic CβG is required for bacterial growth in low osmolarity conditions, the sole requirement for a successful Brucella interaction with mammalian host is its transport to periplasmic space. Our results uncover a new role for CβG in promoting splenomegaly in mice. We showed that CβG-dependent spleen inflammation is the consequence of massive cell recruitment (monocytes, dendritics cells and neutrophils) due to the induction of pro-inflammatory cytokines such as IL-12 and TNF-α and also that the reduced splenomegaly response observed with the cgs mutant is not the consequence of changes in expression levels of the characterized Brucella PAMPs LPS, flagellin or OMP16/19. Complementation of cgs mutant with purified CβG increased significantly spleen inflammation response suggesting a direct role for this polysaccharide.     

The Role of Crowding Forces in Juxtaposing β-Globin Gene Domain Remote Regulatory Elements in Mouse Erythroid Cells

The extremely high concentration of macromolecules in a eukaryotic cell nucleus indicates that the nucleoplasm is a crowded macromolecular solution in which large objects tend to gather together due to crowding forces. It has been shown experimentally that crowding forces support the integrity of various nuclear compartments. However, little is known about their role in control of chromatin dynamics in vivo. Here, we experimentally addressed the possible role of crowding forces in spatial organization of the eukaryotic genome. Using the mouse β-globin domain as a model, we demonstrated that spatial juxtaposition of the remote regulatory elements of this domain in globin-expressing cells may be lost and restored by manipulation of the level of macromolecular crowding. In addition to proving the role of crowding forces in shaping interphase chromatin, our results suggest that the folding of the chromatin fiber is a major determinant in juxtaposing remote genomic elements.     

Role of β-Hairpin Formation in Aggregation: The Self-Assembly of the Amyloid-β(25-35) Peptide

The amyloid-β(25-35) peptide plays a key role in the etiology of Alzheimer's disease due to its extreme toxicity even in the absence of aging. Because of its high tendency to aggregate and its low solubility in water, the structure of this peptide is still unknown. In this work, we sought to understand the early stages of aggregation of the amyloid-β(25-35) peptide by conducting simulations of oligomers ranging from monomers to tetramers. Our simulations show that although the monomer preferentially adopts a β-hairpin conformation, larger aggregates have extended structures, and a clear transition from compact β-hairpin conformations to extended β-strand structures occurs between dimers and trimers. Even though β-hairpins are not present in the final architecture of the fibril, our simulations indicate that they play a critical role in fibril growth. Our simulations also show that β-sheet structures are stabilized when a β-hairpin is present at the edge of the sheet. The binding of the hairpin to the sheet leads to a subsequent destabilization of the hairpin, with part of the hairpin backbone dangling in solution. This free section of the peptide can then recruit an extra monomer from solution, leading to further sheet extension. Our simulations indicate that the peptide must possess sufficient conformational flexibility to switch between a hairpin and an extended conformation in order for β-sheet extension to occur, and offer a rationalization for the experimental observation that overstabilizing a hairpin conformation in the monomeric state (for example, through chemical cross-linking) significantly hampers the fibrillization process.     

A Role for DNA Polymerase μ in the Emerging DJH Rearrangements of the Postgastrulation Mouse Embryo

The molecular complexes involved in the nonhomologous end-joining process that resolves recombination-activating gene (RAG)-induced double-strand breaks and results in V(D)J gene rearrangements vary during mammalian ontogeny. In the mouse, the first immunoglobulin gene rearrangements emerge during midgestation periods, but their repertoires have not been analyzed in detail. We decided to study the postgastrulation DJ_H joints and compare them with those present in later life. The embryo DJ_H joints differed from those observed in perinatal life by the presence of short stretches of nontemplated (N) nucleotides. Whereas most adult N nucleotides are introduced by terminal deoxynucleotidyl transferase (TdT), the embryo N nucleotides were due to the activity of the homologous DNA polymerase μ (Polμ), which was widely expressed in the early ontogeny, as shown by analysis of Polμ^−/− embryos. Based on its DNA-dependent polymerization ability, which TdT lacks, Polμ also filled in small sequence gaps at the coding ends and contributed to the ligation of highly processed ends, frequently found in the embryo, by pairing to internal microhomology sites. These findings show that Polμ participates in the repair of early-embryo, RAG-induced double-strand breaks and subsequently may contribute to preserve the genomic stability and cellular homeostasis of lymphohematopoietic precursors during development.The adaptive immune system is characterized by the great diversity of its antigen receptors, which result from the activities of enzymatic complexes that cut and paste the genomic DNA of antigen receptor loci. The nonhomologous end-joining (NHEJ) machinery is then recruited to repair the double-strand DNA breaks (DSBs) inflicted by the products of the recombination-activating genes (RAGs) (45, 65). Within B cells, each immunoglobulin (Ig) receptor represents a singular shuffling of two heavy (H) and two light (L) chains, which are derived from the recombination of V, D, and J gene segments of the IgH locus and of V and J for IgL (71). Besides these combinatorial possibilities, most Ig variability derives from extensive processing of the coding ends, including exonucleolytic trimming of DNA ends, together with the addition of palindromic (P) nucleotides templated by the adjacent germ line sequence and of nontemplated (N) nucleotides secondary to the activity of the terminal deoxynucleotidyl transferase (TdT), a lymphoid-specific member of family X of DNA polymerases (reviewed in reference 56). During B-lineage differentiation, IgH rearrangements occur before those of the IgL locus, and D-to-J_H rearrangements precede V-to-DJ_H rearrangements (62). DJ_H joints are formed in any of the three open reading frames (ORFs). ORF1 is predominantly used in mature Igs, ORF2 is transcribed as a Dμ protein that provides negative signals to the B-cell precursors, and ORF3 frequently leads to stop codons (32, 33, 37). Germ line V, D, and J gene segments display short stretches of mutually homologous nucleotides (SSH), which are frequently used in gene rearrangements during perinatal periods, when N additions are absent (27, 32, 55, 57). The actual Ig V-region repertoires represent both the results of the NHEJ process associated with genomic VDJ recombination and those of antigen-independent and -dependent selection events. Although the core NHEJ components (Ku-Artemis-DNA-PK and XLF-XRCC4-DNA ligase IV) are by themselves able to join RAG-induced, incompatible DNA ends, family X DNA polymerases can be recruited to fill gaps created by imprecise coding ends with 3′ overhangs (DNA polymerase μ [Polμ] and Polλ) and/or to promote diversity through the addition of N nucleotides (TdT) (34, 56).The lymphoid differentiation pathways and clonotypic repertoires are developmentally regulated and differ between the embryo-fetal and adult periods (2, 44, 68). The perinatal B cells result from a wave of B lymphopoiesis occurring during the last third of mouse gestation (13, 14, 21, 70). Perinatal V_H gene usage differs from that predominating in the adult (1, 69), and the former VDJ joints rarely display N additions, leading to V-region repertoires enriched in multi- and self-reactive specificities (36, 40). The program of B-cell differentiation starts at embryonic days 10 to 11 (E10 to E11) in embryo hematopoietic sites, after the emergence of multipotent progenitors (at E8.5 to E9.5) (18, 19, 23, 31, 51, 73). DJ_H rearrangements were detected in these early embryos, whereas full VDJ_H sequences were not observed before E14 (14, 18, 51, 66), when VJκ rearrangements were also found (63). The earliest mouse DJ_H/VDJ_H Ig sequences analyzed to date corresponded to late fetuses (E16) (14, 53). We reasoned that the true baseline of the Ig rearrangement process occurs in midgestation embryos, when the first DJ_Hs are not yet transcribed and, consequently, not subjected to selection and are conditioned only for the evolutionarily established and developmentally regulated usage of distinct NHEJ machineries.We report here the sequence profiles of the earliest embryo E10 to E12 DJ_H joints. Unexpected frequencies of embryonic DJ_H joints bearing N nucleotides, in the absence of detectable TdT expression, were found. Moreover, the embryo DJ_H joints lacking N nucleotides (N⁻) used fewer SSH to recombine than newborn DJ_Hs, and these SSH were widely dispersed along the embryo D sequences, in contrast to the most joint-proximal ones, which predominated in newborn DJ_Hs. Considering that Polμ is the closest relative of TdT (42% amino acid identity) (22), which is able to introduce N nucleotides in vitro (4, 22, 34, 39, 49) and to join DNA ends with minimal or even null complementarity (17, 58), and that it is expressed in early-embryo organs, we decided to investigate its putative contribution to the first embryo DJ_H joints. The DJ_H joints obtained from Polμ^−/− embryos (48) showed a significant reduction of N nucleotides compared to wild-type (WT) embryos. Moreover, highly preserved DJ_H joints (with <3 deleted nucleotides) were selectively depleted in the Polμ^−/− mouse embryos, while the remaining DJ_Hs preferentially relied upon longer stretches of homology for end ligation. These findings support the idea that Polμ is active during early-embryo DJ_H rearrangements and that both its template-dependent and -independent ambivalent functions may be used to fill in small nucleotide gaps generated after asymmetric hairpin nicking and also to extend coding ends via a limited TdT-like activity.     

The Role of IRE1α in the Degradation of Insulin mRNA in Pancreatic β-Cells

Background

The endoplasmic reticulum (ER) is a cellular compartment for the biosynthesis and folding of newly synthesized secretory proteins such as insulin. Perturbations to ER homeostasis cause ER stress and subsequently activate cell signaling pathways, collectively known as the Unfolded Protein Response (UPR). IRE1α is a central component of the UPR. In pancreatic β-cells, IRE1α also functions in the regulation of insulin biosynthesis.

Principal Findings

Here we report that hyperactivation of IRE1α caused by chronic high glucose treatment or IRE1α overexpression leads to insulin mRNA degradation in pancreatic β-cells. Inhibition of IRE1α signaling using its dominant negative form prevents insulin mRNA degradation. Islets from mice heterozygous for IRE1α retain expression of more insulin mRNA after chronic high glucose treatment than do their wild-type littermates.

Conclusions/Significance

These results reveal a role of IRE1α in insulin mRNA expression under ER stress conditions caused by chronic high glucose. The rapid degradation of insulin mRNA could provide immediate relief for the ER and free up the translocation machinery. Thus, this mechanism would preserve ER homeostasis and help ensure that the insulin already inside the ER can be properly folded and secreted. This adaptation may be crucial for the maintenance of β-cell homeostasis and may explain why the β-cells of type 2 diabetic patients with chronic hyperglycemia stop producing insulin in the absence of apoptosis. This mechanism may also be involved in suppression of the autoimmune type 1 diabetes by reducing the amount of misfolded insulin, which could be a source of “neo-autoantigens.”     

A Novel Role for the Centrosomal Protein,Pericentrin, in Regulation of Insulin Secretory Vesicle Docking in Mouse Pancreatic β-cells

The centrosome is important for microtubule organization and cell cycle progression in animal cells. Recently, mutations in the centrosomal protein, pericentrin, have been linked to human microcephalic osteodysplastic primordial dwarfism (MOPD II), a rare genetic disease characterized by severe growth retardation and early onset of type 2 diabetes among other clinical manifestations. While the link between centrosomal and cell cycle defects may account for growth deficiencies, the mechanism linking pericentrin mutations with dysregulated glucose homeostasis and pre-pubertal onset of diabetes is unknown. In this report we observed abundant expression of pericentrin in quiescent pancreatic β-cells of normal animals which led us to hypothesize that pericentrin may have a critical function in β-cells distinct from its known role in regulating cell cycle progression. In addition to the typical centrosome localization, pericentrin was also enriched with secretory vesicles in the cytoplasm. Pericentrin overexpression in β-cells resulted in aggregation of insulin-containing secretory vesicles with cytoplasmic, but not centrosomal, pericentriolar material and an increase in total levels of intracellular insulin. RNAi- mediated silencing of pericentrin in secretory β-cells caused dysregulated secretory vesicle hypersecretion of insulin into the media. Together, these data suggest that pericentrin may regulate the intracellular distribution and secretion of insulin. Mice transplanted with pericentrin-depleted islets exhibited abnormal fasting hypoglycemia and inability to regulate blood glucose normally during a glucose challenge, which is consistent with our in vitro data. This previously unrecognized function for a centrosomal protein to mediate vesicle docking in secretory endocrine cells emphasizes the adaptability of these scaffolding proteins to regulate diverse cellular processes and identifies a novel target for modulating regulated protein secretion in disorders such as diabetes.     

A “Pedi” Cures All: Toenail Trimming and the Treatment of Ulcerative Dermatitis in Mice

Ulcerative Dermatitis (UD) is the most common cause of unplanned euthanasia in mice used in research, with prevalence rates reported between 4 and 21%. UD is characterized by a deep, ulcerative lesion that appears most commonly over the dorsal neck and is attendant with an intense pruritus. The underlying cause of UD is currently unknown, and as a consequence, there are no directed therapies that resolve lesions reliably. However, there is a growing body of evidence that suggests a behavioral component to the onset, maintenance, and progression of UD lesions. Scratching behavior in response to the intense pruritus associated with UD lesions may be an effective target for interventional therapies. We hypothesized that interfering with scratching behavior by trimming the toenails of mice with UD, would resolve UD lesions. To test this hypothesis, we first evaluated the efficacy of toenail trims with a single application of Vetericyn at the time of treatment versus our previous standard of care, topical Tresaderm applied daily. We found that toenail trims were significantly more effective at resolving lesions (n = 39 toenail trims, n = 100 Tresaderm, p<0.0001) with 93.3% of animals healing by 14 days (median time to lesion resolution). Furthermore, dorsal neck lesions did not recur by 42 days after a single toenail trim (n = 54); however, flank lesions did not resolve and the outcome of the two lesion distributions following treatment were significantly different (p<0.0001). Finally, we implemented toenail trims at an institutional level and found similar efficacies (approximately 90%) for toenail trims regardless of one-time topical supplement used (triple antibiotic ointment, Tresaderm, and Vetericyn, n = 55, 58, 18, p = 0.63). This is the first report of a highly effective treatment for one of the most serious welfare issues in laboratory mice.     

Role of Asp102 in the enzymatic reaction of bovine β-trypsin: A molecular orbital study

Using the X-ray structure of the complex of bovine β-trypsin with the basic pancreatic trypsin inhibitor, the hydrogen-bond structure consisting of Ser195, His57 and Asp102 is clarified in relation to the mechanism of the enzymatic reaction from an ab initio quantum chemical point of view. Under the influence of the inhibitor, of the three hydrogen bonds involving Ser214, His57 and Ala56 around Asp102, and of the other ionic amino acid residues, Asp102 plays a significant role in lowering the barrier height of the proton transfer from Ser195 to His57 without accepting a proton from His57. The principal cause of the barrier height lowering is the electrostatic interaction.     

Total Lignans of Schisandra chinensis Ameliorates Aβ1-42-Induced Neurodegeneration with Cognitive Impairment in Mice and Primary Mouse Neuronal Cells

Lignan compounds extracted from Schisandra chinensis (Turcz.) Baill. have been reported to possess various biological activities, and have potential in the treatment of Alzheimer’s disease. This study was designed to investigate the effects of total lignans of Schisandra chinensis (TLS) on cognitive function and neurodegeneration in the model of AD induced by Aβ_1–42 in vivo and in vitro. It was found that intragastric infusion with TLS (50 and 200 mg/kg) to Aβ_1–42-induced mice significantly increased the number of avoidances in the shuttle-box test and swimming time in the target quadrant in the Morris water maze test. TLS at dose of 200 mg/kg significantly restored the activities of total antioxidant capacity (T-AOC), as well as the level of malondialdehyde (MDA) both in the hippocampus and cerebral cortex in mice. Results of histopathological examination indicated that TLS noticeably ameliorated the neurodegeneration in the hippocampus in mice. On the other hand, TLS (100 μM) could protect the Aβ_1–42-induced primary mouse neuronal cells by blocking the decrease of mitochondrial membrane potential (MMP), change the expressions of Bcl-2 (important regulator in the mitochondria apoptosis pathway). Moreover, TLS also decreased the activity of β-secretase 1 (BACE1), crucial protease contributes to the hydrolysis of amyloid precursor protein (APP), and inhibited the expression of JKN/p38, which involved in the MAPKs signaling pathways in both mice and primary mouse neuronal cells. In summary, TLS might protect against cognitive deficits and neurodegeneration by releasing the damage of oxidative stress, inhibiting the expression of BACE1 and the MAPKs inflammatory signaling pathways.