Huaiqihuang granule attenuate renal injury in IgA vasculitis nephritis by activating AMPK/mTOR-mediated autophagy

Ethnopharmacological relevance: Huaiqihuang granule (HQH) is a traditional Chinese herbal formula comprising Trametes robiniophila Murr., Lycii Fructus., and Polygonatum sibiricum Red. This granule can nourish Qi and Yin, improve blood circulation and remove blood stasis. HQH has been extensively used to improve immune-mediated kidney diseases, such as IgA vasculitis nephritis (IgAVN). However, its renal protective mechanism remains elusive.

Aim of the study: This study investigated whether HQH ameliorates IgAVN by modulating the AMPK/mTOR-mediated Autophagy pathway.

Materials and methods: The IgAVN mouse model was established using gliadin sensitization and India ink-mediated reticuloendothelial blockade (n = 10/group). The model mice were then treated for 4 weeks with low/high-dose HQH (4/8 g/kg/day) or dexamethasone (2.5 mg/kg/day). For in vitro analyses, human mesangial cells (HMCs) were first stimulated with aggregated IgA1 (aIgA1, 25 μg/mL) and then treated with the optimal concentration of HQH-containing serum (40 %). Furthermore, biochemical indices assays, renal histopathology, and immunofluorescence analysis of IgA deposition were performed. Moreover, Autophagy levels were evaluated by assessing the expression of autophagy-related proteins, MDC staining, and mCherry-EGFP-LC3 transfection. Western blot and immunofluorescence were carried out to assess the levels of the AMPK/mTOR pathway proteins and proliferation markers.

Results: The results showed that HQH treatment significantly reduced 24-h urinary protein and serum IgA levels, but improved renal histopathology in IgAVN mice. Furthermore, HQH activated Autophagy by upregulating p-AMPKα, LC3-Ⅱ/LC3-Ⅰ, and Beclin1, while inhibiting p-mTOR/mTOR and p62. Moreover, in HMCs, 40 % HQH-containing serum optimally inhibited aIgA1-induced mesangial proliferation and increased autophagic levels, as evidenced by the quantitative increase in Autophagy activity and mean fluorescence intensity of MDC. However, these effects were blocked by AMPK inhibition.

Conclusion: This study showed that HQH alleviates IgAVN by upregulating AMPK/mTOR-mediated Autophagy, inhibiting mesangial cell proliferation, and mitigating renal injury. These findings suggest that HQH has therapeutic potential for IgAVN and link Autophagy modulation to IgAVN treatment.

AMPK/mTOR pathway; Autophagy; Huaiqihuang granule (HQH); IgA vasculitis nephritis (IgAVN); Mesangial cell proliferation.