Publications

Each of the 24 known integrin subunits has now been inactivated in mice, and a growing number of conditional null lines are becoming available. Lines of mice expressing null mutations in integrin subunit genes have taught us a great deal about the remarkably diverse functions that integrins perform in vivo in mammals. Thorough evaluation of the phenotypes manifested by these lines has also revealed a number of previously unexpected integrin ligands and signaling partners. In this article, we review approaches that can contribute to optimal use of this valuable resource.

The transforming growth factor (TGF)-beta-inducible integrin alpha v beta6 is preferentially expressed at sites of epithelial remodeling and has been shown to bind and activate latent precursor TGF-beta. Herein, we show that alpha v beta6 is overexpressed in human kidney epithelium in membranous glomerulonephritis, diabetes mellitus, IgA nephropathy, Goodpasture's syndrome, and Alport syndrome renal epithelium. To assess the potential regulatory role of alpha v beta6 in renal disease, we studied the effects of function-blocking alpha v beta6 monoclonal antibodies (mAbs) and genetic ablation of the beta6 subunit on kidney fibrosis in Col4A3-/- mice, a mouse model of Alport syndrome. Expression of alpha v beta6 in Alport mouse kidneys was observed primarily in cortical tubular epithelial cells and in correlation with the progression of fibrosis. Treatment with alpha v beta6-blocking mAbs inhibited accumulation of activated fibroblasts and deposition of interstitial collagen matrix. Similar inhibition of renal fibrosis was observed in beta6-deficient Alport mice. Transcript profiling of kidney tissues showed that alpha v beta6-blocking mAbs significantly inhibited disease-associated changes in expression of fibrotic and inflammatory mediators. Similar patterns of transcript modulation were produced with recombinant soluble TGF-beta RII treatment, suggesting shared regulatory functions of alpha v beta6 and TGF-beta. These findings demonstrate that alpha v beta6 can contribute to the regulation of renal fibrosis and suggest this integrin as a potential therapeutic target.

Interleukin 4 receptor alpha (IL-4Ralpha) is essential for effective clearance of gastrointestinal nematode infections. Smooth muscle cells are considered to play a role in the type 2 immune response-driven expulsion of gastrointestinal nematodes. Previous studies have shown in vitro that signal transducer and activator of transcription 6 signaling in response to parasitic nematode infection significantly increases smooth muscle cell contractility. Inhibition of the IL-4Ralpha pathway inhibits this response. How this response manifests itself in vivo is unknown. In this study, smooth muscle cell IL-4Ralpha-deficient mice (SM-MHC(Cre)IL-4Ralpha(-/lox)) were generated and characterized to uncover any role for IL-4/IL-13 in this non-immune cell type in response to Nippostrongylus brasiliensis infection. IL-4Ralpha was absent from alpha-actin-positive smooth muscle cells, while other cell types showed normal IL-4Ralpha expression, thus demonstrating efficient cell-type-specific deletion of the IL-4Ralpha gene. N. brasiliensis-infected SM-MHC(Cre)IL-4Ralpha(-/lox) mice showed delayed ability to resolve infection with significantly prolonged fecal egg recovery and delayed worm expulsion. The delayed expulsion was related to a delayed intestinal goblet cell hyperplasia, reduced T helper 2 cytokine production in the mesenteric lymph node, and reduced M3 muscarinic receptor expression during infection. Together, these results demonstrate that in vivo IL-4Ralpha-responsive smooth muscle cells are beneficial for N. brasiliensis expulsion by coordinating T helper 2 cytokine responses, goblet hyperplasia, and acetylcholine responsiveness, which drive smooth muscle cell contractions.

Recent investigations point to an important role for peptidases in regulating transcellular ion transport by the epithelial Na(+) channel, ENaC. Several peptidases, including furins and proteasomal hydrolases, modulate ENaC maturation and disposal. More idiosyncratically, apical Na(+) transport by ENaC in polarized epithelia of kidney, airway, and gut is stimulated constitutively by one or more trypsin-family serine peptidases, as revealed by inhibition of amiloride-sensitive Na(+) transport by broad-spectrum antipeptidases, including aprotinin and bikunin/SPINT2. In vitro, the transporting activity of aprotinin-suppressed ENaC can be restored by exposure to trypsin. The prototypical channel-activating peptidase (CAP) is a type 1 membrane-anchored tryptic peptidase first identified in Xenopus kidney cells. Frog CAP1 strongly upregulates Na(+) transport when coexpressed with ENaC in oocytes. The amphibian enzyme's apparent mammalian orthologue is prostasin, otherwise known as CAP1, which is coexpressed with ENaC in a variety of epithelia. In airway cells, prostasin is the major basal regulator of ENaC activity, as suggested by inhibition and knockdown experiments. Other candidate regulators of mature ENaC include CAP2/TMPRSS4 and CAP3/matriptase (also known as membrane-type serine protease 1/ST14). Mammalian CAPs are potential targets for treatment of ENaC-mediated Na(+) hyperabsorption by the airway in cystic fibrosis (CF) and by the kidney in hypertension. CAPs can be important for mammalian development, as indicated by embryonic lethality in mice with null mutations of CAP1/prostasin. Mice with selectively knocked out expression of CAP1/prostasin in the epidermis and mice with globally knocked out expression of CAP3/matriptase exhibit phenotypically similar defects in skin barrier function and neonatal death from dehydration. In rats, transgenic overexpression of human prostasin disturbs salt balance and causes hypertension. Thus, several converging lines of evidence indicate that ENaC function is regulated by peptidases, and that such regulation is critical for embryonic development and adult function of organs such as skin, kidney, and lung.

INTRODUCTION

Little is known about behaviors linked to gamma hydroxybutyrate (GHB) morbidity.

METHODS

We surveyed 131 GHB users, using logistic regression to test the associations between the high risk behaviors and hospital treatment for GHB (26 [20%] of subjects).

RESULTS

Increased risk of GHB hospital treatment was associated with: co-ingestion of ethanol (OR 5.2; 95% CI 1.7-16), driving under the influence of GHB (OR 3.2; 95%, CI 1.3-7.8),use of GHB to treat withdrawal symptoms (OR 2.9; 95% CI 1.1-7.9), and co-ingestion of ketamine (OR 2.7; 95% CI 1.1-6.7).

CONCLUSION

Targeted prevention activities could focus on selected high-risk behaviors.

The Phase III Aspreva Lupus Management Study (ALMS) will investigate mycophenolate mofetil (MMF) therapy for lupus nephritis (LN). Eligibility criteria include: 12-75 years of age; diagnosis of systemic lupus erythematosus according to revised American College of Rheumatology criteria; and biopsy-demonstrated LN (Class III-V). Randomized patients will receive open-label induction therapy with MMF or cyclophosphamide in combination with corticosteroids for 24 weeks. The primary efficacy endpoint is treatment response [decreased proteinuria and stabilized (within 25% of baseline) or improved serum creatinine level]. Patients achieving response or complete remission (normalization of all parameters) will be rerandomized to double-blind, placebo-controlled maintenance treatment with MMF or azathioprine, both plus corticosteroids. The maintenance phase primary endpoint is time to treatment failure. To detect a 15% rate improvement in the MMF group compared with cyclophosphamide, and to provide 90% power, a total of 358 patients will be required for the induction phase. On the basis of a projected 278 rerandomized patients, the maintenance phase will have 90% power to detect a difference between treatment groups assuming azathioprine and MMF three-year failure rates of 59.5% and 40.7%, respectively. Aspreva Lupus Management Study may provide invaluable comparative data on the efficacy and safety of MMF as LN induction and maintenance therapy.

BACKGROUND

Inflammation underlies many chronic diseases. The goal of nutritional support in such diseases is to provide adequate energy and nutrients to meet the increased requirements for synthesis of acute phase proteins, inflammatory mediators, antioxidant defenses and the promotion of tissue repair and restoration of cellular function.

CONCLUSIONS

Systemic inflammation alters utilization of various nutrients (fats, carbohydrates and protein) and promotes increased cellular consumption of key antioxidant vitamins and minerals. Some nutrients play a direct role in the resolution of inflammation. These relationships necessitate consideration of the adjunctive role of diet in the natural history of periodontitis.

CLINICAL IMPLICATIONS

Little is known about the role of nutrition in periodontitis. With rapid advances in molecular biology and nutritional genomics in particular, oral health scientists can address this important area of study.

This paper aims to reconcile the use of Palliative Performance Scale (PPSv2) for survival prediction in palliative care through an international collaborative study by five research groups. The study involves an individual patient data meta-analysis on 1,808 patients from four original datasets to reanalyze their survival patterns by age, gender, cancer status, and initial PPS score. Our findings reveal a strong association between PPS and survival across the four datasets. The Kaplan-Meier survival curves show each PPS level as distinct, with a strong ordering effect in which higher PPS levels are associated with increased length of survival. Using a stratified Cox proportional hazard model to adjust for study differences, we found females lived significantly longer than males, with a further decrease in hazard for females not diagnosed with cancer. Further work is needed to refine the reporting of survival times/probabilities and to improve prediction accuracy with the inclusion of other variables in the models.