The Role of RIPK1 Pathways in Obesity and Circadian Rhythm Regulation

Abstract

RIPK1 and MLKL are best known for executing necroptosis, yet emerging evidence implicates them in metabolic control. We tested whether modulating these proteins reshapes adipose biology and glucose regulation through non-lethal signalling. Using complementary in vivo and in vitro approaches, we combined adipose-targeted genetic manipulation with longitudinal metabolic phenotyping, depot-level endpoints, 3T3-L1 adipogenesis assays, and circadian profiling of hepatic clock-linked transcripts. Attenuating RIPK1 signalling aligned with reduced inflammatory tone in adipose tissue and indices consistent with improved insulin sensitivity, in keeping with RIPK1’s scaffolding of NF-κB pathways that antagonise insulin signalling. Effects on fat distribution favoured a relative reduction in visceral depots rather than a simple fall in total adiposity, suggesting qualitative remodelling of adipose function. MLKL influenced adipocyte programs beyond cell death: loss of MLKL impaired differentiation in vitro and pointed to altered lipid-handling pathways in vivo. Rhythmic analyses supported genotype-dependent modulation of hepatic transcripts, compatible with feedback between lipid status and clock-controlled transcription. Together, these data support a model in which RIPK1 and MLKL shape immunometabolic signalling and insulin sensitivity via context-dependent, non-necroptotic functions. The findings motivate depot-aware and time-of-day interventions and prioritise follow-up experiments coupling RIPK1 inhibition or MLKL manipulation with direct measures of PPARγ targets, adiponectin multimers, and responses to inflammatory challenge.