The Journal of Immunology Prmt2 Regulates the Lipopolysaccharide-Induced Responses in Lungs and Macrophages Emilie Dalloneau,* Patricia Lopes Pereira,* Ve ´ronique Brault,* Elizabeth G. Nabel, † and Yann He ´rault* ,‡ Precise control of the LPS stimulation in the lung modulates inflammation and airway hyperresponsiveness involving the well- known TLR4/NF-kB pathway. As a consequence, the expression and secretion of proinflammatory cytokines is tightly regulated with the recruitment of neutrophils. Changes in the LPS-induced responses have been observed in the Prmt2-Col6a1 monosomic model, suggesting the presence of dosage-sensitive genes controlling LPS pathway in the mouse. In this article, we report that the Prmt2 regulates the LPS-induced lung responses in lungs and macrophages. We demonstrate that Prmt2 gene dosage influences the lung airway hyperresponsiveness, the recruitment of neutrophils, and the expression of proinflammatory cytokines, such as IL-6 and TNF-a. In addition, Prmt2 loss of function also altered the nuclear accumulation of NF-kB in stimulated macrophages. Prmt2 should be considered as a new member of the NF-kB pathway controlling LPS-induced inflammatory and lung responses in a dosage-dependent manner, certainly through regulating nuclear accumulation of NF-kB as shown already in fibroblasts. The Journal of Immunology, 2011, 187: 4826–4834. T he LPS after intranasal instillation induces a complex response in the lungs that is tightly regulated (1). The LPS binds adaptors and activates the TLR4, leading to the activation of different signaling pathways that will elicit the lung and the inflammatory responses. Part of the control is due to specific adaptor proteins that contribute to the integrated response. In the classical TLR4/MyD88 pathway, NF-kB is normally se- questered in the cytoplasm by an IkB complex (2–6), and the phosphorylation of IkB by inducible kinases, such as IkB kinase 1 (IkK1) and IkK2, leads to subsequent ubiquitination and degra- dation of these proteins. The released NF-kB then translocates to the nucleus, where it stimulates the transcription of genes involved in immune and inflammatory responses (7). NF-kB DNA binding and NF-kB–dependent transcription are attenuated by newly syn- thesized IkB-a in the nucleus, which associates with NF-kB/RelA complexes. As IkB-a accumulates in the nucleus, there is a pro- gressive reduction of both NF-kB DNA binding and NF-kB– dependent transcription (8), presumably by export of NF-kB/IkB-a complexes from the nucleus (9–11). An additional pathway, in- dependent of MyD88/MyD88-adaptor like and NF-kB, is regu- lated by TRAM and moderately by Toll/IL-1R domain containing adaptor inducing IFN-b (TRIF), leading to the late activation of NF-kB (12), and activates type I IFN synthesis (13). LPS-induced inflammation is the consequence of the activation of the reticuloendothelial system leading to the synthesis of various mediators that have a local but also a general action. The principal proinflammatory cytokines are the IL-1, the IL-6, and the TNF-a. Expressions of IL-6 and TNF-a are directly regulated by NF-kB (14, 15), and these molecules are responsible for the amplification of the inflammatory response and part of the systemic responses (16). In the course of our study to isolate mouse dosage-sensitive genes homologous to human chromosome 21 (Hsa21) genes, we developed a new mouse model of monosomy for the Prmt2-Col6a1 (noted Ms1Yah) genetic interval found on the mouse chromosome 10 (17). The Ms1Yah model is deleted for 14 genes corresponding to the telomeric end of Hsa21, which was shown to display several copy number variants, in particular some that affect the Prmt2, S100B, and the genes. The only phenotype of the Ms1Yah mice is an impaired airway response and an increased inflammatory re- sponse after LPS stimulation. Further investigations showed mac- rophages (MF) as an important cellular compartment for the in- creased production of proinflammatory cytokines. Several genes of the Pmrt2-Col6a1 region were found to be dosage sensitive in lungs and MF, and are probably involved in phenotypes observed in Ms1Yah mice (17). To further explain the increased production of IL-6 and TNF-a in Ms1Yah mice in response to LPS, we focused our attention on the Prmt2, which modifies arginine residues during posttranslational modification of proteins (18). PRMT2 is known to act as a nega- tive regulator of the NF-kB pathway in a dose-dependent manner. In fibroblasts, Prmt2 exerts its effect by causing nuclear accu- mulation of IkB-a, which concomitantly decreases nuclear NF-kB DNA binding (19). Thus, we hypothesized that the decrease in the copy number of this gene is at the origin of the increase of the inflammatory response observed in the Ms1Yah model. Indeed, the expression of proinflammatory cytokines IL-6 and TNF-a is NF-kB dependent and increases in Ms1Yah mice after stimula- tion with LPS. In this study, we demonstrated the involvement of Prmt2 in the inflammatory response and determined how Prmt2 heterozygotes could recapitulate the defects observed in Ms1Yah mice. The conclusion of this study is that Prmt2 is a dosage- sensitive gene contributing to the control of the LPS-induced *Centre National de la Recherche Scientifique, Institut de Ge ´ne ´tique Biologie Mole ´culaire et Cellulaire, INSERM, Universite ´ de Strasbourg, Unite ´ Mixte de Recherche 7104, Unite ´ Mixte de Recherche 964, 67404 Illkirch, France; † Na- tional Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892; and ‡ Institut Clinique de la Souris, 67404 Illkirch, France Received for publication April 15, 2011. Accepted for publication August 22, 2011. This work was supported by the National Centre for Scientific Research and the European commission with the AnEUploidy project (LSHG-CT-2006-037627). Address correspondence and reprint requests to Dr. Yann He ´rault, Institut de Ge ´ne ´t- ique Biologie Mole ´culaire et Cellulaire, CNRS, INSERM, Universite ´ de Strasbourg, UMR7104, UMR964, 1 rue Laurent Fries, 67404 Illkirch, France. E-mail address: herault@igbmc.fr Abbreviations used in this article: ADMA, asymmetric dimethylarginine; AHR, air- way hyperresponse; BALF, bronchoalveolar lavage fluid; IkK1, IkB kinase 1; MF, macrophage; MPO, myeloperoxidase; PenH, parameter of enhanced pause; TRIF, Toll/IL-1R domain containing adaptor inducing IFN-b; wt, wild-type. www.jimmunol.org/cgi/doi/10.4049/jimmunol.1101087