BACKGROUND: Leptin, the adipocyte-secreted hormone that regulates weight, is 
known to link lipid metabolism with inflammation in various cell types. However, 
its role in human sebocytes has not yet been investigated.
OBJECTIVES: The purpose of this study was to investigate the effects of leptin 
in human sebaceous gland biology.
METHODS: Expression of the long form of the leptin receptor (Ob-Rb) was detected 
by real-time quantitative reverse transcriptase polymerase chain reaction 
(qRT-PCR) and immunochemistry. Lipid analysis was by high-performance thin-layer 
chromatography, gas chromatography-mass spectrometry and time-of-flight mass 
spectrometer mass detection. Lipid bodies were visualized by BODIPY staining 
using fluorescent microscopy and measured by flow cytometry. Interleukin (IL)-6 
and IL-8 mRNA levels were assessed by real-time qRT-PCR and their release was 
evaluated by enzyme-linked immunosorbent assay. Cyclooxygenase (COX)-2 and 
5-lipooxygenase (LOX) protein expression and phosphorylation of p65 and signal 
transducer and activator of transcription (STAT)-3 were determined by Western 
blot analysis.
RESULTS: Expression of Ob-Rb was detected in human sebaceous glands and in 
cultured human SZ95 sebocytes. The treatment of SZ95 sebocytes with leptin led 
to enlarged intracellular lipid bodies, increased ratios of 
unsaturated/saturated fatty acids and decreased vitamin E levels. Further 
supporting a proinflammatory role, leptin induced COX-2 and 5-LOX expression in 
SZ95 sebocytes and augmented the production of IL-6 and IL-8 cytokines. On 
leptin treatment, the STAT-3 and nuclear factor-κB pathways were activated, 
indicating that these known leptin signalling pathways are active in human 
sebocytes.
CONCLUSIONS: Our findings suggest that leptin signalling may be involved in the 
proinflammatory regulation of sebaceous lipid metabolism and the induction of 
inflammatory enzymes and cytokines.