-The transmembrane glycoprotein CD38 in airway smooth muscle is the source of cyclic-ADP ribose, an intracellular calcium-releasing molecule, and is subject to regulatory effects of cytokines such as interleukin (IL)-13, a cytokine implicated in asthma. We investigated the role of CD38 in airway hyperresponsiveness using a mouse model of IL-13-induced airway disease. Wild-type (WT) and CD38-deficient (CD38KO) mice were intranasally challenged with 5 g of IL-13 three times on alternate days under isoflurane anesthesia. Lung resistance (RL) in response to inhaled methacholine was measured 24 h after the last challenge in pentobarbital-anesthetized, tracheostomized, and mechanically ventilated mice. Bronchoalveolar cytokines, bronchoalveolar and parenchymal inflammation, and smooth muscle contractility and relaxation using tracheal segments were also evaluated. Changes in methacholine-induced R L were significantly greater in the WT than in the CD38KO mice following intranasal IL-13 challenges. Airway reactivity after IL-13 exposure, as measured by the slope of the methacholine dose-response curve, was significantly higher in the WT than in the CD38KO mice. The rate of isometric force generation in tracheal segments (e.g., smooth muscle reactivity) was greater in the WT than in the CD38KO mice following incubation with IL-13. IL-13 treatment reduced isoproterenol-induced relaxations to similar magnitudes in tracheal segments obtained from WT and CD38KO mice. Both WT and CD38KO mice developed significant bronchoalveolar and parenchymal inflammation after IL-13 challenges compared with naïve controls. The results indicate that CD38 contributes to airway hyperresponsiveness in lungs exposed to IL-13 at least partly by increasing airway smooth muscle reactivity to contractile agonists. interleukin-13; inflammation; asthma; eosinophil; airway smooth muscle CD38 IS A MULTIFUNCTIONAL ECTOENZYME that catalyzes the conversion of ␤-nicotinamide adenine dinucleotide to cyclic ADP-ribose (cADPR) and ADP-ribose (16). Both CD38 and its product cADPR are present in airway smooth muscle (ASM) cells and other mammalian cell types (8,26,32,39). Together with inositol 1,4,5-trisphosphate, cADPR is an important mediator of intracellular calcium ([Ca 2ϩ ] i ) release in smooth muscle cells including that of the airways (7,20,31). The dynamics of [Ca 2ϩ ] i responses to stimuli are central in the regulation of ASM contraction, bronchomotor tone, and airway caliber (33). cADPR induces Ca 2ϩ release from the sarcoplasmic reticulum through activation of ryanodine receptor channels in ASM cells (31). The [Ca 2ϩ ] i responses of human ASM cells exposed to acetylcholine, thrombin, and bradykinin are reduced by the competitive cADPR antagonist 8-bromo-cADPR in a magnitude that correlates positively with the level of CD38 expression (6).CD38-deficient (CD38KO) mice have been used to elucidate the role of CD38 in the function of several organs. CD38-generated cADPR plays a critical role in Ca 2ϩ -induced insulin secretion (21), os...

PV isolation and lesion completeness were improved with Arctic Front Advance, while no unexpected findings were found related to safety.

CD38 is involved in normal airway function, IL-13-induced airway hyperresponsiveness (AHR), and is also regulated by tumor necrosis factor (TNF)-α in airway smooth muscle (ASM) cells. This study aimed to determine whether TNF-α-induced CD38 upregulation in ASM cells contributes to AHR, a hallmark of asthma. We hypothesized that AHR would be attenuated in TNF-α-exposed CD38-deficient (CD38KO) mice compared with wild-type (WT) controls. Mice ( n = 6–8/group) were intranasally challenged with vehicle control or TNF-α (50 ng) once and every other day during 1 or 4 wk. Lung inflammation and AHR, measured by changes in lung resistance after inhaled methacholine, were assessed 24 h following the last challenge. Tracheal rings were incubated with TNF-α (50 ng/ml) to assess contractile changes in the ASM. While a single TNF-α challenge caused no airway inflammation, both multiple-challenge protocols induced equally significant inflammation in CD38KO and WT mice. A single intranasal TNF-α challenge induced AHR in the WT but not in the CD38KO mice, whereas both mice developed AHR after 1 wk of challenges. The AHR was suppressed by extending the challenges for 4 wk in both mice, although to a larger magnitude in the WT than in the CD38KO mice. TNF-α increased ASM contractile properties in tracheal rings from WT but not from CD38KO mice. In conclusion, CD38 contributes to TNF-α-induced AHR after a brief airway exposure to the cytokine, likely by mediating changes in ASM contractile responses, and is associated with greater AHR remission following chronic airway exposure to TNF-α. The mechanisms involved in this remission remain to be determined.

CD38 is a cell-surface protein involved in calcium signaling and contractility of airway smooth muscle. It has a role in normal airway responsiveness and in airway hyperresponsiveness (AHR) developed following airway exposure to IL-13 and TNF-α but appears not to be critical to airway inflammation in response to the cytokines. CD38 is also involved in T cell-mediated immune response to protein antigens. In this study, we assessed the contribution of CD38 to AHR and inflammation to two distinct allergens, ovalbumin and the epidemiologically relevant environmental fungus Alternaria. We also generated bone marrow chimeras to assess whether Cd38(+/+) inflammatory cells would restore AHR in the CD38-deficient (Cd38(-/-)) hosts following ovalbumin challenge. Results show that wild-type (WT) mice develop greater AHR to inhaled methacholine than Cd38(-/-) mice following challenge with either allergen, with comparable airway inflammation. Reciprocal bone marrow transfers did not change the native airway phenotypic differences between WT and Cd38(-/-) mice, indicating that the lower airway reactivity of Cd38(-/-) mice stems from Cd38(-/-) lung parenchymal cells. Following bone marrow transfer from either source and ovalbumin challenge, the phenotype of Cd38(-/-) hosts was partially reversed, whereas the airway phenotype of the WT hosts was preserved. Airway inflammation was similar in Cd38(-/-) and WT chimeras. These results indicate that loss of CD38 on hematopoietic cells is not sufficient to prevent AHR and that the magnitude of airway inflammation is not the predominant underlying determinant of AHR in mice.

Cryptococcus neoformans var. grubii was identified at necropsy in a case of bilateral otitis interna in a 7-year-old, female, domestic shorthair cat with a 9-day history of acute onset of vestibular disease. Gross examination, including that of the middle and inner ears, was unremarkable. Histologically, the auricular vestibuli, cochleae, and semicircular canals were bilaterally affected by granulomatous inflammation with extracellular and intrahistiocytic yeasts. The yeasts and associated inflammation obstructed and disrupted perilymphatic and endolymphatic spaces of the inner ears. Disruption of the saccular and utricular maculae, cristae ampularis, and organ of Corti, as well as changes in the endolymphatic and perilymphatic fluids, probably impaired the vestibular and auditory functions of this cat. The route of infection was most likely hematogenous.