Mesenchymal stem cells alleviate rat diabetic nephropathy by suppressing CD103+ DCs-mediated CD8+ T cell responses.

Diabetic nephropathy (DN) as a kind of serious microvascular complication of Diabetes Mellitus (DM) usually causes the end-stage of renal disease (ESRD). Studies have demonstrated that CD103+ dendritic cells (DCs) exhibited a renal pathogenic effect in murine chronic kidney disease (CKD). Mesenchymal stem cells (MSCs) can alleviate DN and suppress the DCs maturation. To explore the role of CD103+ DCs and the potential mechanisms underlying MSCs-mediated protective effects in DN, we used bone marrow MSCs (BM-MSCs) to treat DN rats. MSCs transplantation considerably recovered kidney function and diminished renal injury, fibrosis and the population of renal CD103+ DCs in DN rat. The MSCs-treated DN rats had decreased mRNA expression levels of interleukin (IL)1ß, IL6, tumour necrosis factor alpha (TNF-α), monocyte chemotactic protein 1 (MCP-1) and reduced CD8 T cell infiltration in the kidney. MSCs significantly down-regulated the genes expression of transcription factors (Basic leucine zipper transcriptional factor ATF-like 3, Batf3 and DNA-binding protein inhibitor ID-2, Id2) and FMS-like tyrosine kinase-3 (Flt3) which are necessary for CD103+ DCs development. The protective effect of MSCs may be partly related to their immunosuppression of CD8+ T cell proliferation and activation mediated by CD103+ DCs in the kidney of DN rats.

Peritoneal M2 macrophage transplantation as a potential cell therapy for enhancing renal repair in acute kidney injury.

Acute kidney injury (AKI) is a clinical condition that is associated with high morbidity and mortality. Inflammation is reported to play a key role in AKI. Although the M2 macrophages exhibit antimicrobial and anti-inflammatory activities, their therapeutic potential has not been evaluated for AKI. This study aimed to investigate the protective effect of peritoneal M2 macrophage transplantation on AKI in mice. The macrophages were isolated from peritoneal dialysates of mice. The macrophages were induced to undergo M2 polarization using interleukin (IL)-4/IL-13. AKI was induced in mice by restoring the blood supply after bilateral renal artery occlusion for 30 minutes. The macrophages were injected into the renal cortex of mice. The changes in renal function, inflammation and tubular proliferation were measured. The M2 macrophages were co-cultured with the mouse primary proximal tubular epithelial cells (PTECs) under hypoxia/reoxygenation conditions in vitro. The PTEC apoptosis and proliferation were analysed. The peritoneal M2 macrophages effectively alleviated the renal injury and inflammatory response in mice with ischaemia-reperfusion injury (IRI) and promoted the PTEC proliferation in vivo and in vitro. These results indicated that the peritoneal M2 macrophages ameliorated AKI by decreasing inflammatory response and promoting PTEC proliferation. Hence, the peritoneal M2 macrophage transplantation can serve as a potential cell therapy for renal diseases.

Honokiol ameliorates cisplatin-induced acute kidney injury via inhibition of mitochondrial fission.

BACKGROUND AND PURPOSE: Mitochondrial damage and oxidative stress are crucial contributors to the tubular cell injury and death in acute kidney injury. Novel therapeutic strategies targeting mitochondria protection and halting the progression of acute kidney injury are urgently needed. Honokiol is a small-molecule polyphenol that exhibits extraordinary cytoprotective effects, such as anti-inflammatory and anti-oxidative. Thus, we investigated whether honokiol could ameliorate cisplatin-induced acute kidney injury via preventing mitochondrial dysfunction. EXPERIMENTAL APPROACH: Acute kidney injury was induced by cisplatin administration. Biochemical and histological analysis were used to determine kidney injury. The effect of honokiol on mitochondrial function and morphology were determined using immunohistochemistry, transmission electron microscopy, immunoblot and immunofluorescence. To investigate the mechanism by which honokiol alters mitochondrial dynamics, remodelling and resistance to apoptosis, we used transfection experiments, immunoblotting, immunoprecipitation and flow cytometry assay. KEY RESULTS: We demonstrated that the prominent mitochondrial fragmentation occurred in experimental models of cisplatin-induced nephrotoxicity, which was coupled to radical oxygen species (ROS) overproduction, deterioration of mitochondrial function, release of apoptogenic factors and the consequent apoptosis. Honokiol treatment caused notable reno-protection and attenuated of these cisplatin-induced changes. Mechanistically, honokiol treatment recovered the expression of SIRT3 and improved AMPK activity in tubular cells exposure to cisplatin, which preserved the Drp1 phosphorylation at Ser637 and blocked its translocation in mitochondria, consequently preventing mitochondrial fragmentation and subsequent cell injury and death. CONCLUSION AND IMPLICATIONS: Our results indicate that honokiol may protect against cisplatin-induced acute kidney injury by preserving mitochondrial integrity and function by SIRT3/AMPK-dependent mitochondrial dynamics remodelling.

Phloretin ameliorates hyperuricemia-induced chronic renal dysfunction through inhibiting NLRP3 inflammasome and uric acid reabsorption.

BACKGROUND: Hyperuricemia (HUA) is an important risk factor for renal diseases and contributes to renal fibrosis. It has been proved that phloretin has antioxidant and anti-inflammatory properties and could inhibit uric acid (UA) uptake in vitro. However, whether phloretin has a renal protective role in vivo remains unknown. PURPOSE: This study aims to evaluate the therapeutic effect of phloretin on HUA-induced renal injury in mice and to reveal its underlying mechanism. METHODS: Mice were induced hyperuricemic by oral gavage of adenine/potassium oxonate. The effects of phloretin on renal function, fibrosis, oxidative stress, inflammation, and UA metabolism in HUA mice were evaluated. The effect of phloretin on NLRP3 pathway was analyzed in human renal tubular cell lines (HK-2). RESULTS: HUA mice showed renal dysfunction with increased renal fibrosis, inflammation and mitochondrial stress. By contrast, phloretin reduced the level of serum blood urea nitrogen (BUN), urinary albumin to creatinine ratio (UACR), tubular necrosis, extracellular matrix (ECM) deposition and interstitial fibroblasts in HUA mice. The renal infiltration of inflammatory cells, cytokines such as NOD-like receptor family pyrin domain containing 3 (NLRP3) and interleukin-1ß (IL-1ß) release, mitochondrial reactive oxygen species (ROS) and morphological lesions in HUA mice also decreased. Furthermore, phloretin partly inhibited renal glucose transporter 9 (GLUT9) and promoted urinary UA excretion in HUA mice. In vitro, phloretin suppressed the NLPR3 pathway under LPS or UA stimulation in HK-2 cells. CONCLUSIONS: Phloretin could effectively attenuate UA-induced renal injury via co-inhibiting NLRP3 and UA reabsorption, and thus it might be a potential therapy to hyperuricemia-related renal diseases.