Expression of the leptin receptor outside of bone marrow-derived cells regulates tuberculosis control and lung macrophage MHC expression.

TitleExpression of the leptin receptor outside of bone marrow-derived cells regulates tuberculosis control and lung macrophage MHC expression.
Publication TypeJournal Article
Year of Publication2011
AuthorsLemos MP, Rhee KY, McKinney JD
JournalJ Immunol
Volume187
Issue7
Pagination3776-84
Date Published2011 Oct 01
ISSN1550-6606
KeywordsAnimals, Bacterial Load, Bone Marrow Cells, Cell Separation, Chemotaxis, Leukocyte, Flow Cytometry, Lung, Macrophages, Alveolar, Major Histocompatibility Complex, Mice, Mice, Inbred C57BL, Mice, Mutant Strains, Receptors, Leptin, Reverse Transcriptase Polymerase Chain Reaction, Th1 Cells, Tuberculosis
Abstract

Leptin is a pleiotropic hormone proposed to link nutritional status to the development of strong Th1 immunity. Because Mycobacterium tuberculosis control is affected by starvation and diabetes, we studied the role of the leptin receptor in regulating distinct immune cells during chronic infection. Infected db/db mice, bearing a natural mutation in the leptin receptor, have a markedly increased bacterial load in their lungs when compared with that of their wild-type counterparts. In response to M. tuberculosis infection, db/db mice exhibited disorganized granulomas, neutrophilia, and reduced B cell migration to the lungs, correlating with dysfunctional lung chemokine responses that include XCL1, CCL2, CXCL1, CXCL2, and CXCL13. In a db/db lung, myeloid cells were delayed in their production of inducible NO synthase and had reduced expression of MHC I and II. Although the Th1 cell response developed normally in the absence of leptin signaling, production of pulmonary IFN-γ was delayed and ineffective. Surprisingly, a proper immune response took place in bone marrow (BM) chimeras lacking leptin receptor exclusively in BM-derived cells, indicating that leptin acts indirectly on immune cells to modulate the antituberculosis response and bacterial control. Together, these findings suggest that the pulmonary response to M. tuberculosis is affected by the host's nutritional status via the regulation of non-BM-derived cells, not through direct action of leptin on Th1 immunity.

DOI10.4049/jimmunol.1003226
Alternate JournalJ Immunol
PubMed ID21859958
PubMed Central IDPMC3178734
Grant ListR01 HL088906 / HL / NHLBI NIH HHS / United States
R01 HL088906-04 / HL / NHLBI NIH HHS / United States
R01 HL088906-05 / HL / NHLBI NIH HHS / United States
R01 HL088906-06 / HL / NHLBI NIH HHS / United States