Extreme diversity, conservation, and convergence of spider silk fibroin sequences

Spiders (Araneae) spin high-performance silks from liquid fibroin proteins. Fibroin sequences from basal spider lineages reveal mosaics of amino acid motifs that differ radically from previously described spider silk sequences. The silk fibers of Araneae are constructed from many protein designs. Yet, the repetitive sequences of fibroins from orb-weaving spiders have been maintained, presumably by stabilizing selection, over 125 million years of evolutionary history. The retention of these conserved motifs since the Mesozoic and their convergent evolution in other structural superproteins imply that these sequences are central to understanding the exceptional mechanical properties of orb weaver silks.

Human eosinophils have prolonged survival, enhanced functional properties, and become hypodense when exposed to human interleukin 3

Human eosinophils were cultured in the presence of recombinant human IL-3 for up to 14 d and their biochemical, functional, and density properties were assessed. After 3 d of culture in 10 pM IL-3, eosinophils had a viability of 70% compared with only 10% in enriched medium alone. Neither IL-1 alpha, IL-2, IL-4, tumor necrosis factor, basic fibroblast growth factor, nor platelet-derived growth factor maintained eosinophil viability. The 7- and 14-d survival of the cultured eosinophils was 55 and 53%, respectively. No other cell type, including neutrophils, was present after culture. After 7 d of culture, the normodense eosinophils were converted to hypodense cells as assessed by density centrifugation. Eosinophils exposed to 1,000 pM IL-3 for 30 min or cultured in 10 pM IL-3 for 7 d generated approximately threefold more leukotriene C4 (LTC4) in response to calcium ionophore than freshly isolated cells. Furthermore, whereas freshly isolated eosinophils killed only 14% of the antibody-coated Schistosoma mansoni larvae, these eosinophils killed 54% of the larvae when exposed to 100 pM IL-3. The enhanced helminth cytotoxicity was maintained for 7 d when eosinophils were cultured in the presence of both 10 pM IL-3 and 3T3 fibroblasts, but not when eosinophils were cultured in the presence of IL-3 alone. IL-3 thus maintains the viability of eosinophils in vitro, augments the calcium ionophore-induced generation of LTC4, enhances cytotoxicity against antibody-sensitized helminths, and induces the eosinophils to become hypodense cells. These phenotypic changes in the eosinophil may be advantageous to host defense against helminthic infections but may be disadvantageous in conditions such as allergic disease.

Clinical characteristics with inflammation profiling of long COVID and association with 1-year recovery following hospitalisation in the UK: a prospective observational study

BACKGROUND

No effective pharmacological or non-pharmacological interventions exist for patients with long COVID. We aimed to describe recovery 1 year after hospital discharge for COVID-19, identify factors associated with patient-perceived recovery, and identify potential therapeutic targets by describing the underlying inflammatory profiles of the previously described recovery clusters at 5 months after hospital discharge.

METHODS

The Post-hospitalisation COVID-19 study (PHOSP-COVID) is a prospective, longitudinal cohort study recruiting adults (aged ≥18 years) discharged from hospital with COVID-19 across the UK. Recovery was assessed using patient-reported outcome measures, physical performance, and organ function at 5 months and 1 year after hospital discharge, and stratified by both patient-perceived recovery and recovery cluster. Hierarchical logistic regression modelling was performed for patient-perceived recovery at 1 year. Cluster analysis was done using the clustering large applications k-medoids approach using clinical outcomes at 5 months. Inflammatory protein profiling was analysed from plasma at the 5-month visit. This study is registered on the ISRCTN Registry, ISRCTN10980107, and recruitment is ongoing.

FINDINGS

2320 participants discharged from hospital between March 7, 2020, and April 18, 2021, were assessed at 5 months after discharge and 807 (32·7%) participants completed both the 5-month and 1-year visits. 279 (35·6%) of these 807 patients were women and 505 (64·4%) were men, with a mean age of 58·7 (SD 12·5) years, and 224 (27·8%) had received invasive mechanical ventilation (WHO class 7-9). The proportion of patients reporting full recovery was unchanged between 5 months (501 [25·5%] of 1965) and 1 year (232 [28·9%] of 804). Factors associated with being less likely to report full recovery at 1 year were female sex (odds ratio 0·68 [95% CI 0·46-0·99]), obesity (0·50 [0·34-0·74]) and invasive mechanical ventilation (0·42 [0·23-0·76]). Cluster analysis (n=1636) corroborated the previously reported four clusters: very severe, severe, moderate with cognitive impairment, and mild, relating to the severity of physical health, mental health, and cognitive impairment at 5 months. We found increased inflammatory mediators of tissue damage and repair in both the very severe and the moderate with cognitive impairment clusters compared with the mild cluster, including IL-6 concentration, which was increased in both comparisons (n=626 participants). We found a substantial deficit in median EQ-5D-5L utility index from before COVID-19 (retrospective assessment; 0·88 [IQR 0·74-1·00]), at 5 months (0·74 [0·64-0·88]) to 1 year (0·75 [0·62-0·88]), with minimal improvements across all outcome measures at 1 year after discharge in the whole cohort and within each of the four clusters.

INTERPRETATION

The sequelae of a hospital admission with COVID-19 were substantial 1 year after discharge across a range of health domains, with the minority in our cohort feeling fully recovered. Patient-perceived health-related quality of life was reduced at 1 year compared with before hospital admission. Systematic inflammation and obesity are potential treatable traits that warrant further investigation in clinical trials.

FUNDING

UK Research and Innovation and National Institute for Health Research.

Bronchodilator S-nitrosothiol deficiency in asthmatic respiratory failure

BACKGROUND

Nitric oxide (NO) gas concentrations are high in the expired air of individuals with asthma, but not consistently so in the expired air of people with pneumonia. S-nitrosothiols are naturally occurring bronchodilators, the concentrations of which are raised in the airways of patients with pneumonia. Airway S-nitrosothiols have not been studied in asthma.

METHODS

Tracheal S-nitrosothiol concentrations from eight asthmatic children in respiratory failure were compared with those of 21 children undergoing elective surgery.

RESULTS

Mean S-nitrosothiol concentrations in asthmatic children were lower than in normal children (65 [SD 45] nmol/L vs 502 [SD 429] nmol/L) and did not vary with inspired oxygen concentration or airway thiol concentration.

INTERPRETATION

Severe asthma is associated with low concentrations of airway S-nitrosothiols. This is the first reported deficiency of an endogenous bronchodilator in the human asthmatic airway lining fluid. We suggest that S-nitrosothiol metabolism may be a target for the development of new asthma therapies.

Glucagon receptor knockout mice are resistant to diet-induced obesity and streptozotocin-mediated beta cell loss and hyperglycaemia

AIMS/HYPOTHESIS

Under normal physiological conditions, glucagon signalling is important in glucose homeostasis. Hyperglucagonaemia or altered insulin:glucagon ratio plays a role in maintaining hyperglycaemia in subjects with type 2 diabetes. It has been reported that glucagon receptor knockout (Gcgr (-/-)) mice develop normally and have lower plasma glucose on a normal diet. The goal of the current research was to further investigate the role of glucagon signalling in metabolic control and glucose homeostasis.

METHODS

Gcgr (-/-) mice were challenged with a high-fat diet (HFD) and with streptozotocin, which induces beta cell damage. They were then analysed for whole-body and serum metabolic phenotypes as well as pancreatic islet morphology.

RESULTS

In comparison with wild-type mice, Gcgr (-/-) mice exhibited decreased body weight and food intake, reduced plasma glucose levels, and improved oral and intraperitoneal glucose tolerance. Elevated glucagon-like peptide-1 levels and reduced gastric emptying were also observed in Gcgr (-/-) mice, which also had reduced HFD-induced hyperinsulinaemia and hyperleptinaemia, and were resistant to the development of hepatic steatosis. In addition, Gcgr (-/-) mice were resistant to STZ-induced hyperglycaemia and pancreatic beta cell destruction.

CONCLUSIONS/INTERPRETATION

This study demonstrates that blocking glucagon signalling by targeted Gcgr gene deletion leads to an improvement in metabolic control in this mouse model.

Efficacy of potential chemopreventive agents on rat colon aberrant crypt formation and progression

We assessed the effects of 78 potential chemopreventive agents in the F344 rat using two assays in which the inhibition of carcinogen-induced aberrant crypt foci (ACF) in the colon was the measure of efficacy. In both assays ACF were induced by the carcinogen azoxymethane (AOM) in F344 rats by two sequential weekly injections at a dose of 15 mg/kg. Two weeks after the last AOM injection, animals were evaluated for the number of aberrant crypts detected in methylene blue stained whole mounts of rat colon. In the initiation phase protocol agents were given during the period of AOM administration, whereas in the post-initiation assay the chemopreventive agent was introduced during the last 4 weeks of an 8 week assay, a time when ACF had progressed to multiple crypt clusters. The agents were derived from a priority listing based on reports of chemopreventive activity in the literature and/or efficacy data from in vitro models of carcinogenesis. During the initiation phase carboxyl amidoimidazole, p-chlorphenylacetate, chlorpheniramine maleate, D609, diclofenac, etoperidone, eicosatetraynoic acid, farnesol, ferulic acid, lycopene, meclizine, methionine, phenylhexylisothiocyanate, phenylbutyrate, piroxicam, 9-cis-retinoic acid, S-allylcysteine, taurine, tetracycline and verapamil were strong inhibitors of ACF. During the post-initiation phase aspirin, calcium glucarate, ketoprofen, piroxicam, 9-cis-retinoic acid, retinol and rutin inhibited the outgrowth of ACF into multiple crypt clusters. Based on these data, certain phytochemicals, antihistamines, non-steroidal anti-inflammatory drugs and retinoids show unique preclinical promise for chemoprevention of colon cancer, with the latter two drug classes particularly effective in the post-initiation phase of carcinogenesis.

The dynamin-dependent, arrestin-independent internalization of 5-hydroxytryptamine 2A (5-HT2A) serotonin receptors reveals differential sorting of arrestins and 5-HT2A receptors during endocytosis

5-Hydroxytryptamine 2A (5-HT2A) receptors, a major site of action of clozapine and other atypical antipsychotic medications, are, paradoxically, internalized in vitro and in vivo by antagonists and agonists. The mechanisms responsible for this paradoxical regulation of 5-HT2A receptors are unknown. In this study, the arrestin and dynamin dependences of agonist- and antagonist-mediated internalization were investigated in live cells using green fluorescent protein (GFP)-tagged 5-HT2A receptors (SR2-GFP). Preliminary experiments indicated that GFP tagging of 5-HT2A receptors had no effect on either the binding affinities of several ligands or agonist efficacy. Likewise, both the native receptor and SR2-GFP were internalized via endosomes in vitro. Experiments with a dynamin dominant-negative mutant (dynamin K44A) demonstrated that both agonist- and antagonist-induced internalization were dynamin-dependent. By contrast, both the agonist- and antagonist-induced internalization of SR2-GFP were insensitive to three different arrestin (Arr) dominant-negative mutants (Arr-2 V53D, Arr-2-(319-418), and Arr-3-(284-409)). Interestingly, 5-HT2A receptor activation by agonists, but not antagonists, induced greater Arr-3 than Arr-2 translocation to the plasma membrane. Importantly, the agonist-induced internalization of 5-HT2A receptors was accompanied by differential sorting of Arr-2, Arr-3, and 5-HT2A receptors into distinct plasma membrane and intracellular compartments. The agonist-induced redistribution of Arr-2 and Arr-3 into intracellular vesicles and plasma membrane compartments distinct from those involved in 5-HT2A receptor internalization implies novel roles for Arr-2 and Arr-3 independent of 5-HT2A receptor internalization and desensitization.

Distribution of HLA class 1 antigens in normal human tissue and in mammary cancer

With a monoclonal antibody which reacts with all HLA class 1 antigens it was found that these antigens are not uniformly distributed in all nucleated cells. Rather HLA class 1 antigens are restricted in their distribution to lymphoid cells, endothelial cells of small vessels, and certain epithelia including mammary duct cells. These antigens were not detected on hepatocytes, specialised cells of the central nervous system, or on the tumour cells of 8 out of 17 human mammary cancers. Given the hypothesis that T cells only respond to foreign antigens on cells which share a common major histocompatibility antigen, these results imply that the T cell responses to viral infections of hepatocytes--for example, hepatitis B virus and the CNS--for example, subacute sclerosing encephalitis, are mediated through an antigen system other than HLA class 1. The absence of HLA class 1 antigen on many mammary cancer cells may be of prognostic significance if T cell modulation of tumour growth is mediated through this class of antigens.

Expired nitric oxide as a marker for childhood asthma

Expression of the inflammatory isoform of the enzyme nitric oxide synthase (NOS) is increased in airway-lining cells of patients with asthma. The NOS product nitric oxide (NO.) was measured in the expired gas of children with asthma. Vital capacity expirates from 21 control subjects and 13 subjects with asthma were assayed by chemiluminescence. Measurements were highly reproducible (coefficient of variation, 2.6% +/- 1.1%) and did not vary with age, sex, height, or weight. Patients with asthma had mean NO. levels (16.3 parts per billion) that were more than threefold higher than those of control subjects (5.05 ppb; p < 0.001). Expired NO. decreased as airflow obstruction improved during corticosteroid treatment (r2 = 0.77; n = 7; p < 0.001) but remained higher than normal (13.5 ppb; n = 5; p < 0.01) even after airflow obstruction resolved. We demonstrate the use of a reproducible test for asthma in children that is independent of measures of airflow obstruction. We speculate that expired NO assays may prove to be a more sensitive measure of childhood asthma than spirometry.

Peroxisome proliferator-activated receptor gamma is induced during differentiation of colon epithelium cells

Peroxisome proliferator-activated receptor gamma (PPARgamma), a fatty acid-activated nuclear receptor, is implicated in adipocyte differentiation and insulin sensitisation. In view of the association of dietary fat intake and bowel disease, the expression of PPARgamma in rodent and human intestine was studied. Expression of PPARgamma mRNA was examined by Northern blot hybridisation, RNase protection, and/or competitive RT-PCR assays, whereas PPARgamma protein levels were evaluated by immunoblotting and immunohistochemistry. PPARgamma mRNA and protein were abundantly expressed in colon relative to the small intestine both in rodents and in man. Interestingly, expression of PPARgamma was primarily localised in the more differentiated epithelial cells in the colon. The level of expression of PPARgamma in colon was similar to the levels seen in adipose tissue. Expression of PPARgamma increased from proximal to distal segments of the colon in man. In Caco-2 and HT-29 human adenocarcinoma cells, PPARgamma expression increased upon differentiation, consistent with PPARgamma being associated with a differentiated epithelial phenotype. High-level expression of PPARgamma was observed in the colon, but not in the small intestine, suggesting a potential role of this nuclear receptor in the colon.

The role of lithotripsy and its side effects

The relative roles of extracorporeal shock wave lithotripsy and percutaneous nephrostolithotomy currently are being debated. Both treatment modalities are applicable to most upper urinary tract calculi. However, there are some important distinctions between the 2 techniques. Over-all, extra-corporeal shock wave lithotripsy is associated with significantly lower morbidity than percutaneous nephrostolithotomy but stone-free rates are lower for extracorporeal shock wave lithotripsy than for percutaneous nephrostolithotomy. This difference is slight for kidneys containing minimal stone burden but increases in direct proportion to increasing stone burden. The morbidity of extracorporeal shock wave lithotripsy also increases with increasing stone burden. When applied to the treatment of staghorn calculi the morbidity of both techniques is comparable but the stone-free rates are significantly better with percutaneous nephrostolithotomy. Treatment with extracorporeal shock wave lithotripsy produces changes in the kidney similar to that of renal trauma, consisting primarily of intraparenchymal and perirenal hemorrhage and edema. While the acute effects of extracorporeal shock wave lithotripsy are well tolerated by most patients, the long-term sequela of this form of therapy is not well established. Potential long-term adverse effects reported include loss of renal function, hypertension and an increased rate of new stone occurrence. The effect of shock waves on renal parenchyma in experimental animals is dose-dependent (number of shock waves). Magnetic resonance imaging of patients treated with extracorporeal shock wave lithotripsy demonstrates morphological abnormalities in or around the kidney in 63 to 85 per cent of the cases (average number of shock waves 1,200). Despite these observations the safe limits of extracorporeal shock wave lithotripsy in humans have yet to be established. Further study regarding this issue and the potential long-term adverse effects of extracorporeal shock wave lithotripsy is needed urgently.

Clinical evidence of herb-drug interactions: a systematic review by the natural standard research collaboration

To evaluate the pharmacokinetics and adverse effects of medicinal herbs, as well as clinical evidence of herb-drug interactions.

METHODS

Electronic searches were conducted in multiple databases, including MEDLINE, EMBASE, the Cochrane Library, CINAHL, NAPRALERT, International Pharmaceutical Abstracts, CANCERLIT, CISCOM, and HerbMed. Search terms used included common names, scientific names, and synonyms for the herbs and their primary active constituents. Bibliographies of relevant articles were also searched by hand to obtain additional references. No restrictions were placed on language or quality of publications. All literature collected pertained to adverse effects, pharmacokinetics, and suspected or confirmed cases of herb-drug interactions.

RESULTS

Over 80 herbs or botanicals (including plants, fungi, algae, and common constituents) were identified that had clinically significant interactions with prescription and over-the-counter drugs. Interestingly, herbs beginning with the letter "g" (garlic, ginger, ginkgo, and grapefruit) were among the herbs most commonly involved in herb-drug interactions. Drugs with anticoagulant/antiplatelet activity (e.g. warfarin, aspirin) were frequently implicated in herb-drug interactions, with documented interactions with over 30 herbs and herbal products. Because many herbs have demonstrated adverse effects on the liver, the potential for interaction with hepatotoxic agents (such as acetaminophen) is also significant. Clinical outcomes of reported herb-drug interactions ranged from mild to severe. Of note, fatalities (though rare) have occurred with concomitant ephedra and caffeine use.

CONCLUSION

As herbal products (and dietary supplements in general) continue to grow in popularity, patients and health care providers should be vigilant of potential herb-drug interactions.

Expression of expanded repeat androgen receptor produces neurologic disease in transgenic mice

Spinal and bulbar muscular atrophy (SBMA) is a motor neuron disease caused by the expansion of a polyglutamine tract within the androgen receptor. This disease is unusual among the polyglutamine diseases in that it involves lower motor and sensory neurons, with relative sparing of other brain structures. We describe the development of transgenic mice, created with a truncated, highly expanded androgen receptor driven by the neurofilament light chain promoter, which develop many of the motor symptoms of SBMA. In addition, transgenic mice created with the prion protein promoter develop widespread neurologic disease, reminiscent of juvenile forms of other polyglutamine diseases. Thus, in these experiments, the distribution of neurologic symptoms depends on the expression level and pattern of the promoter used, rather than on specific characteristics of androgen receptor metabolism or function. The transgenic mice described here develop neuronal intranuclear inclusions (NIIs), a hallmark of SBMA and the other polyglutamine diseases. We have shown these inclusions to be ubiquitinated and to sequester molecular chaperones, components of the 26S proteasome and the transcriptional activator CREB-binding protein. Apart from the presence of NIIs, evidence of neuropathology or neurogenic muscle atrophy was absent, suggesting that the neurologic phenotypes observed in these mice were the result of neuronal dysfunction rather than neuronal degeneration. These mice will provide a useful resource for characterizing specific aspects of motor neuron dysfunction, and for testing therapeutic strategies for this and other polyglutamine diseases.

New anti-lung-cancer antibody cluster 12 reacts with human folate receptors present on adenocarcinoma

Human folate receptor (hFR, folate-binding protein) is a single-chain glycoprotein with high specific affinity for folic acid and methotrexate. We have created 4 monoclonal antibodies (MAbs) to hFR, all of which react specifically with purified hFR in Western blots. Flow cytometry indicated that the antibodies all had patterns of reactivity against epithelial cell lines similar to that of antibody MW207 (workshop antibody 12), labeling 2 breast-tumor cell lines and 2 of 5 SCLC without labeling the one non-small-cell carcinoma tested. We used the antibodies to trace the in situ distribution of hFR in histologically normal tissues and in lung tumors by a sensitive alkaline-phosphatase-anti-alkaline-phosphatase immunohistochemical technique. In frozen sections of normal lung, hFR was diffusely distributed on cell membranes of type-1 and type-2 pneumocytes and mucociliary and basilar respiratory epithelial cells of distal bronchi. The receptor was focally expressed by mucociliary cells of proximal respiratory mucosa and by macrophages, but was not detected in stromal smooth muscle, fibroblasts or lymphoid cells. In tumors, hFR was heavily and diffusely expressed on cell membranes of 9 of 10 pulmonary adenocarcinomas, 5 of 5 bronchioloalveolar carcinomas and 2 of 2 carcinoid tumors. It was focally expressed in 3 of 5 large-cell lung carcinomas and was absent from 4 of 5 small-cell carcinomas, 18 of 22 invasive squamous carcinomas, 2 of 2 in situ squamous carcinomas, and 13 of 13 squamous dysplasias of bronchial mucosa. We conclude that hFR is heavily expressed in situ by normal alveolar and bronchial epithelium and by adenocarcinoma of lung. It is usually absent from small-cell carcinoma and squamous tumors at levels detectable by immunohistochemistry.

Effects of time of insemination relative to ovulation on pregnancy rate and embryonic-loss rate in mares

The effects of pre-ovulatory and post ovulatory insemination on pregnancy rate and embryonic-loss rate were studied in 268 mares in two experiments. Within each experiment mares were randomised within replicates as follows: to be inseminated on the day the pre-ovulatory follicle reached 35 mm (pre-ovulatory group), to be inseminated on the day of ovulation (Day 0 group), and to be inseminated on the day after ovulation (Day 1 group). Ultrasonic pregnancy diagnoses were performed on Days 11, 12, 13 and 14 (Experiment 1) and Days 11, 12, 13, 14, 15, 20 and 40 (Experiment 2). Combined for the two experiments, pregnancy rates were different (P less than 0.01) among the three groups. For Experiment 2, pregnancy rate within the pre-ovulatory group was lower (P less than 0.05) for insemination 4 days or more before ovulation than for up to 3 days before ovulation. Pregnancy rate was lower (P less than 0.05) for the Day 0 group than for the pre-ovulatory group inseminated up to 3 days before ovulation. In Experiment 2, ovulation was detected by examinations every 6 h; pregnancy rate was greater (P less than 0.05) for mares inseminated 0 to 6 h after ovulation than for mares inseminated at 18 to 24 h. No pregnancies occurred when mares were inseminated 30 h or more after ovulation. The mean day of first detection of the embryonic vesicle was different (P less than 0.0001) among the three groups. Diameter of embryonic vesicle averaged over Days 11 to 15 also differed (P less than 0.0001) among groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Aggression and fighting behavior among African-American adolescents: individual and family factors

OBJECTIVES

This study examined the extent to which individual and family factors are associated with aggression and fighting behavior among African-American middle school adolescents.

METHODS

Four hundred thirty-six African-American boys and girls from two middle schools in a predominantly low-income North Carolina school system were surveyed and their school records examined. Information was collected concerning students' aggression levels, school fighting behavior, school suspensions for fighting, attitudes toward violence, perceptions of their families' attitudes toward violence, weapon-carrying behavior, and sociodemographics. Multivariate analyses were employed to predict the students' aggression levels, fighting behavior, and school suspensions.

RESULTS

Factors related to the individual adolescents, such as gender, age, weapon-carrying behavior, and attitudes toward violence, were associated with students' reports of aggression and fighting behavior. Factors related to family and school were associated with school suspension for fighting.

CONCLUSIONS

This study suggests that violence prevention programs set in our elementary and middle schools may reduce aggression and fighting among our youth. School teachers and public health practitioners are encouraged to work together in understanding and preventing adolescent violence.

Preclinical development of CAT-354, an IL-13 neutralizing antibody, for the treatment of severe uncontrolled asthma

BACKGROUND AND PURPOSE

IL-13 is a pleiotropic Th2 cytokine considered likely to play a pivotal role in asthma. Here we describe the preclinical in vitro and in vivo characterization of CAT-354, an IL-13-neutralizing IgG4 monoclonal antibody (mAb), currently in clinical development.

EXPERIMENTAL APPROACH

In vitro the potency, specificity and species selectivity of CAT-354 was assayed in TF-1 cells, human umbilical vein endothelial cells and HDLM-2 cells. The ability of CAT-354 to modulate disease-relevant mechanisms was tested in human cells measuring bronchial smooth muscle calcium flux induced by histamine, eotaxin generation by normal lung fibroblasts, CD23 upregulation in peripheral blood mononuclear cells and IgE production by B cells. In vivo CAT-354 was tested on human IL-13-induced air pouch inflammation in mice, ovalbumin-sensitization and challenge in IL-13 humanized mice and antigen challenge in cynomolgus monkeys.

KEY RESULTS

CAT-354 has a 165 pM affinity for human IL-13 and functionally neutralized human, human variant associated with asthma and atopy (R130Q) and cynomolgus monkey, but not mouse, IL-13. CAT-354 did not neutralize human IL-4. In vitro CAT-354 functionally inhibited IL-13-induced eotaxin production, an analogue of smooth muscle airways hyperresponsiveness, CD23 upregulation and IgE production. In vivo in humanized mouse and cynomolgus monkey antigen challenge models CAT-354 inhibited airways hyperresponsiveness and bronchoalveolar lavage eosinophilia.

CONCLUSIONS AND IMPLICATIONS

CAT-354 is a potent and selective IL-13-neutralizing IgG4 mAb. The preclinical data presented here support the trialling of this mAb in patients with moderate to severe uncontrolled asthma.

Role of skeletal muscle in thiazolidinedione insulin sensitizer (PPARgamma agonist) action

Thiazolidinedione (TZD) insulin sensitizers are specific agonists of peroxisome proliferator activated receptor (PPAR)gamma. However, their mechanism of action and the in vivo target tissue(s) that mediate insulin sensitization remain poorly defined. Although PPARgamma messenger RNA expression has been reported in skeletal muscle, the expression of PPARgamma within myocytes in intact muscle tissue has not been examined. An antipeptide PPARgamma antibody was generated; immunohistochemistry was then used to demonstrate that PPARgamma is present within nuclei of myocytes [in both skeletal (white and red fibers) and cardiac tissue (rodent and human)]. The effect of insulin sensitizer treatment on muscle insulin action was studied using ob/ob mice after 4 days dosing with a potent (6 nM PPARgamma Kd) TZD (10 mg/kg x day). 2-deoxyglucose (2-DOG) uptake was then assessed in freshly isolated soleus muscles from lean vs. ob/ob vs. TZD-treated ob/ob mice. In lean mouse muscles, 2-DOG uptake was stimulated by 82%, 95%, 165% (with 25, 100, 2000 microU/ml insulin); muscles from ob/ob were severely insulin resistant (<80% stimulation with 2000 microU/ml insulin). Muscles from TZD-treated ob/ob displayed a normal insulin response with 100 (71%) or 2000 (158%) microU/ml insulin. Additional studies were performed using ZDF rats treated with/without TZD for 7 days. In vivo 2-DOG glucose uptake into soleus, gastrocnemius, and diaphragm muscles was measured during euglycemic-hyperinsulinemic clamp. Compared with lean rats, muscle 2-DOG uptake in ZDF was reduced by 52% (soleus) or 71% (diaphragm). Partial (40-60%) normalization of the reduced 2-DOG uptake was evident in TZD-treated ZDF rats. In contrast to the effect of in vivo treatment on muscle insulin action, preincubation of isolated soleus muscles from naive lean or ob/ob mice for 5 h with 100 nM TZD did not affect insulin-stimulated 2-DOG uptake. We conclude: 1) PPARgamma is expressed in myocytes within skeletal and cardiac muscle. 2) In vivo activation of PPARgamma by treatment of insulin-resistant mice/rats with a potent TZD corrects impaired muscle insulin action. 3) The lack of a direct effect on muscle after 5 h in vitro TZD incubation suggests that changes in insulin action may require a longer duration of PPARgamma activation or that improved muscle insulin sensitivity may result from an indirect in vivo effect of PPARgamma activation (e.g. changes in systemic lipid metabolism).