42 research outputs found
Position space formulation for Dirac fermions on honeycomb lattice
We study how to construct Dirac fermion defined on the honeycomb lattice in
position space. Starting from the nearest neighbor interaction in tight binding
model, we show that the Hamiltonian is constructed by kinetic term and second
derivative term of three flavor Dirac fermions in which one flavor has a mass
of cutoff order and the other flavors are massless. In this formulation the
structure of the Dirac point is simplified so that its uniqueness can be easily
shown even if we consider the next-nearest neighbor interaction. We also show
the chiral symmetry at finite lattice spacing, which protects the masslessness
of the Dirac fermion, and discuss the analogy with the staggered fermion
formulation.Comment: 19 pages, 7 figure
In vivo induction of activin A-producing alveolar macrophages supports the progression of lung cell carcinoma
Alveolar macrophages (AMs) are crucial for maintaining normal lung function. They are abundant in lung cancer tissues, but their pathophysiological significance remains unknown. Here we show, using an orthotopic murine lung cancer model and human carcinoma samples, that AMs support cancer cell proliferation and thus contribute to unfavourable outcome. Inhibin beta A (INHBA) expression is upregulated in AMs under tumor-bearing conditions, leading to the secretion of activin A, a homodimer of INHBA. Accordingly, follistatin, an antagonist of activin A is able to inhibit lung cancer cell proliferation. Single-cell RNA sequence analysis identifies a characteristic subset of AMs specifically induced in the tumor environment that are abundant in INHBA, and distinct from INHBA-expressing AMs in normal lungs. Moreover, postnatal deletion of INHBA/activin A could limit tumor growth in experimental models. Collectively, our findings demonstrate the critical pathological role of activin A-producing AMs in tumorigenesis, and provides means to clearly distinguish them from their healthy counterparts.Taniguchi S., Matsui T., Kimura K., et al. In vivo induction of activin A-producing alveolar macrophages supports the progression of lung cell carcinoma. Nature Communications 14, 143 (2023); https://doi.org/10.1038/s41467-022-35701-8