Mathematical analysis for spatial distribution of vessels, mast cells and adipocytes in superficial fascia

Activation of aryl hydrocarbon receptor ameliorates degranulation of LL-37 induced mast cells in rosacea through enhancing autophagy

BACKGROUND

Activation of the aryl hydrocarbon receptor (AhR) ameliorates LL-37-induced rosacea-like dermatitis in mice, whereas mast cells and cytokine overexpression are prominent features in rosacea skin.

OBJECTIVE

To evaluate the potential mechanisms of AhR activation on autophagy and degranulation of mast cells in rosacea.

METHODS

LL-37 treated mast cells were used to mimic rosacea. An AhR agonist (tapinarof) was applied to LL-37 induced mast cells. Furthermore, an autophagy agonist (RAPA) and an inhibitor (CQ) was added to investigate the mechanisms of autophagy. Western blot and RT-qPCR assessed cell degranulation (Cma1, Tpsab1) and cytokines (MMP9, TNF-α, and IL-6). Changes in cell morphology were observed under a microscope. Autophagy markers (LC3 and p62) were examined using Western blot and cellular immunofluorescence.

RESULTS

LL-37 upregulated the expressions of Cma1, Tpsab1, MMP9, TNF-α, and IL-6, which were then reduced by tapinarof treatment for 24 h. LC3B-I was converted to LC3B-II and p62 was reduced gradually with increasing concentration of tapinarof, indicating that autophagy was enhanced. RAPA enhanced the expression of LC3B-II on LL-37-induced mast cells, similar to tapinarof, while CQ partially inhibited the ability of tapinarof to induce autophagy in mast cells. Moreover, CQ reversed tapinarof's suppression of Cma1, Tpsab1, MMP9, TNF-α and IL-6 on LL-37 treated mast cells.

CONCLUSION

The present study showed that activation of AhR ameliorated degranulation of LL-37-induced mast cells in rosacea through enhancing autophagy, offering a new option for rosacea treatment.

Suramin, an antiparasitic drug, stimulates adipocyte differentiation and promotes adipogenesis

BACKGROUND

Previous studies demonstrated that mast cells with their degranulated component heparin are the major endogenous factors that stimulate preadipocyte differentiation and promote fascial adipogenesis, and this effect is related to the structure of heparin. Regarding the structural and physiological properties of the negatively charged polymers, hexasulfonated suramin, a centuries-old medicine that is still used for treating African trypanosomiasis and onchocerciasis, is assumed to be a heparin-related analog or heparinoid. This investigation aims to elucidate the influence of suramin on the adipogenesis.

METHODS

To assess the influence exerted by suramin on adipogenic differentiation of primary white adipocytes in rats, this exploration was conducted both in vitro and in vivo. Moreover, it was attempted to explore the role played by the sulfonic acid groups present in suramin in mediating this adipogenic process.

RESULTS

Suramin demonstrated a dose- and time-dependent propensity to stimulate the adipogenic differentiation of rat preadipocytes isolated from the superficial fascia tissue and from adult adipose tissue. This stimulation was concomitant with a notable upregulation in expression levels of pivotal adipogenic factors as the adipocyte differentiation process unfolded. Intraperitoneal injection of suramin into rats slightly increased adipogenesis in the superficial fascia and in the epididymal and inguinal fat depots. PPADS, NF023, and NF449 are suramin analogs respectively containing 2, 6, and 8 sulfonic acid groups, among which the last two moderately promoted lipid droplet formation and adipocyte differentiation. The number and position of sulfonate groups may be related to the adipogenic effect of suramin.

CONCLUSIONS

Suramin emerges as a noteworthy pharmaceutical agent with the unique capability to significantly induce adipocyte differentiation, thereby fostering adipogenesis.