Pattern recognition receptors (PRR), toll-like receptors (TLR), and nucleotide-oligomerization domain containing proteins (NOD) play critical roles in mediating inflammation and modulating functions in white adipocytes in obesity. However, the role of PRR activation in brown adipocytes, which are recently found to be present in adult humans, has not been studied. Here we report that mRNA of TLR4, TLR2, NOD1 and NOD2, are up-regulated, paralleled with up-regulated mRNA of inflammatory cytokine and chemokine in BAT of the obese mice. During brown adipocyte differentiation, mRNA and protein expression of NOD1and TLR4, but not TLR2 and NOD2, are also increased. Activation of TLR4, TLR2, or NOD1 in brown adipocytes induces activation of NF-B and MAPK signaling pathways, leading to inflammatory cytokines/chemokine mRNA expression and/or protein secretion. Moreover, activation of TLR4, TLR2, or NOD1, attenuates both basal and isoproterenol-induced uncoupling protein 1 expression without affecting mitochondrial biogenesis and lipid accumulation in brown adipocytes. Cellular bioenergetics measurements confirm that attenuation of UCP-1 expression by PRR activation is accompanied by suppression of both basal and isoproterenol-stimulated oxygen consumption rates, isoproterenol-induced uncoupled respiration from proton leak and coupling efficiency; however, maximal respiration and ATP-coupled respiration are not changed. Further, the attenuation of UCP-1 by PRR activation appears to be mediated through downregulation of the UCP-1 promoter activities. Taken together, our results demonstrate the role of selected PRR activation in inducing inflammation and down-regulation of UCP-1 expression and mitochondrial respiration in brown adipocytes. Our results uncover novel targets in BAT for obesity treatment and prevention.