Abstract: ObjectiveTo investigate the effect of high glucose (HG)-treated Raw264.7 macrophage derived exosomes
(Exos) on the podocyte injury, and to explore whether its mechanism is related to the inhibition of autophagy. Methods
The exosomes from high glucose-treated Raw264.7 cells (HG-Exos) and primary podocyte cells were incubated for 24 h, and
the internalization of Exos in primary podocyte cells was detected. Primary podocytes were treated with different doses of
Exos (0, 7, 14, 28, 56 and 112 mg/L) extracted by HG to investigate the effects of HG-Exos on podocyte survival and
autophagy. The primary podocytes were divided into control group, HG-Exos group, chloroquine group, HG-Exos +
chloroquine group, rapamycin group and HG-Exos + rapamycin group. The formation of autophagy was observed by
transmission electron microscopy. The effects of HG-Exos on the proliferation of primary podocyte cells were evaluated by
CCK-8 assay. The expressions of LC3B, Beclin 1 and Nephrin protein were detected by Western blot assay. Results
Raw264.7 cells treated by the HG produced an increased number of Exos compared to Raw264.7 cells treated with normal
glucose (P＜0.05). Confocal laser microscopy showed that PKH67-labeled Exos were localized to the perinuclear region of
podocytes. CCK-8 assay showed that the podocyte viability reduced dose- and time-dependently after exposure to HGExos. Western blot assay showed that HG-Exos decreased the accumulation of Nephrin, Beclin 1 and the conversion of
LC3- Ⅰ to LC3- Ⅱ in podocytes. Compared to 0 mg/L HG-Exos group, the autophagic double-membrane compartments
containing lamellar structures in podocytes were significantly increased in the 7, 14 and 28 mg/L HG-Exos groups (P＜ 0.05). The expressions of Nephrin, Beclin 1 and LC3B, and the number of autophagosomes were significantly higher in
rapamycin group and HG-Exos group + rapamycin group than those of HG-Exos group, chloroquine group and HG-Exos +
chloroquine group (P＜0.05). ConclusionHG-treated macrophage derived exosomes can decrease podocyte activity and
increase podocyte damage, and its mechanism is related to the reduction of podocyte autophagy.

Key words: macrophages, exosomes, podocytes, autophagy, high glucose