Discovery of a Novel Small-Molecule Modulator of C-X-C Chemokine Receptor Type 7 as a Treatment for Cardiac Fibrosis.

C-X-C chemokine receptor type 7 (CXCR7) is involved in cardiac and immune pathophysiology. We report the discovery of a novel 1,4-diazepine CXCR7 modulator, demonstrating for the first time the role of pharmacological CXCR7 intervention in cardiac repair. Structure-activity-relationship (SAR) studies demonstrated that a net reduction in lipophilicity (log D) and an incorporation of saturated ring systems yielded compounds with good CXCR7 potencies and improvements in oxidative metabolic stability in human-liver microsomes (HLM). Tethering an ethylene amide further improved the selectivity profile (e.g., for compound 18, CXCR7 Ki = 13 nM, adrenergic α 1a Kb > 10 000 nM, and adrenergic ß 2 Kb > 10 000 nM). The subcutaneous administration of 18 in mice led to a statistically significant increase in circulating concentrations of plasma stromal-cell-derived factor 1α (SDF-1α) of approximately 2-fold. Chronic dosing of compound 18 in a mouse model of isoproterenol-induced cardiac injury further resulted in a statistically significant reduction of cardiac fibrosis.

Altered regulation of aquaporin gene expression in allergen and IL-13-induced mouse models of asthma.

IL-13 is known to affect many processes that contribute to an asthmatic phenotype, including inflammation, fibrosis, and mucus production. Members of the aquaporin (AQP) family of transmembrane water channels are targets of regulation in models of lung injury and inflammation. Therefore, we examined AQP mRNA and protein expression in allergen and IL-13-induced mouse models of asthma. Lungs from ovalbumin sensitized and ovalbumin challenged (OVA/OVA) and IL-13 treated mice showed airway thickening, increased mucus production, and pulmonary eosinophilia. Pulmonary function tests showed a significant increase in methacholine-induced airway hyperreactivity in OVA/OVA and IL-13-treated mice as compared with controls. Quantitative PCR analysis revealed differential regulation of AQPs in these two models. AQP1 and AQP4 mRNA expression was downregulated in the OVA/OVA model, but not in the IL-13 model. AQP5 mRNA was reduced in both models, whereas AQP3 was upregulated only in the IL-13 model. Western analysis showed that diminished expression of an apically localized aquaporin, (AQP5), and concomitant upregulation of a basolateral aquaporin (AQP3 or AQP4) are characteristic features of both inducible asthma models. These results demonstrate that aquaporins are common targets of gene expression in both allergen and IL-13 induced mouse models of asthma.

TH1-mediated airway hyperresponsiveness independent of neutrophilic inflammation.

BACKGROUND: T(H)2-mediated allergic asthma is characterized by eosinophilia, mucus overproduction, and airway hyperresponsiveness (AHR). Although it is clear that T(H)2 cells and their cytokines play an important role in AHR, the roles of T(H)1 cells and neutrophils in AHR are controversial. OBJECTIVE: We sought to determine the roles of T(H)1 cells and neutrophils in AHR. METHODS: Ovalbumin-specific CD4(+) T cells were purified from DO11.10 mice, differentiated into T(H)1 cells, and injected into naive BALB/c, IL-4RalphaKO, or IL-8RKO mice. After ovalbumin antigen challenge, cytokine mRNA levels in lung samples, as well as inflammatory cell types and numbers in bronchoalveolar lavage fluid (BALF), were determined. AHR was assessed by measuring resistance in tracheostomized mice and enhanced pause in freely moving mice. RESULTS: T(H)1 cells induced AHR as robust as T(H)2 cells. They also induced lung inflammation dominated by neutrophils. Neither AHR nor inflammation were reduced when T(H)1 cells were transferred into IL-4RalphaKO mice. When IL-8RKO mice were used as recipients of T(H)1 cells, neutrophilia was greatly reduced, but the AHR was as strong as that seen in wild-type mice. On the other hand, dexamethasone treatment had no effect on neutrophilia but has significantly reduced AHR. Reduction in AHR was accompanied by a reduction in the numbers of lymphocytes and macrophages in BALF. CONCLUSIONS: T(H)1 cells can induce strong AHR independent of IL-4 and IL-13. The AHR is associated with the presence of lymphocytes and macrophages, but not neutrophils, in BALF. Our results point to a pathway whereby T(H)1 cells mediate AHR independent of neutrophilic inflammation.