Obesity is associated with inflammation that can drive metabolic defects such as 
hyperlipidemia and insulin resistance. Specific metabolites can contribute to 
inflammation, but nutrient intake and obesity are also associated with altered 
bacterial load in metabolic tissues (i.e. metabolic endotoxemia). These 
bacterial cues can contribute to obesity-induced inflammation. The specific 
bacterial components and host receptors that underpin altered metabolic 
responses are emerging. We previously showed that Nucleotide-binding 
oligomerization domain-containing protein 1 (NOD1) activation with bacterial 
peptidoglycan (PGN) caused insulin resistance in mice. We now show that PGN 
induces cell-autonomous lipolysis in adipocytes via NOD1. Specific bacterial PGN 
motifs stimulated lipolysis in white adipose tissue (WAT) explants from WT, but 
not NOD1⁻/⁻mice. NOD1-activating PGN stimulated mitogen activated protein 
kinases (MAPK),protein kinase A (PKA), and NF-κB in 3T3-L1 adipocytes. The 
NOD1-mediated lipolysis response was partially reduced by inhibition of ERK1/2 
or PKA alone, but not c-Jun N-terminal kinase (JNK). NOD1-stimulated lipolysis 
was partially dependent on NF-κB and was completely suppressed by inhibiting 
ERK1/2 and PKA simultaneously or hormone sensitive lipase (HSL). Our results 
demonstrate that bacterial PGN stimulates lipolysis in adipocytes by engaging a 
stress kinase, PKA, NF-κB-dependent lipolytic program. Bacterial NOD1 activation 
is positioned as a component of metabolic endotoxemia that can contribute to 
hyperlipidemia, systemic inflammation and insulin resistance by acting directly 
on adipocytes.