No abstract

CXCL14 is a relatively novel chemokine with a wide spectrum of biological activities. The present study was designed to investigate whether CXCL14 overexpression attenuates sepsis-associated acute kidney injury (AKI) in mice. Sepsis model has been established by cecal ligation and puncture (CLP). CLP induced AKI in mice as assessed by increased renal neutrophil gelatinase-associated lipocalin (NGAL) expression and serum creatinine levels. We found that renal CXCL14 expression in the kidney was significantly decreased at 12 hours after CLP. Correlation analysis demonstrated a negative association between renal CXCL14 expression and AKI markers including serum creatinine and renal NGAL. Moreover, CXCL14 overexpression reduced cytokine (TNF-α, IL-6, and IL-1β) production and NGAL expression in the kidney and decreased serum creatinine levels. In vivo and in vitro experiments found that CXCL14 overexpression inhibited M1 macrophage polarization but increased M2 polarization. Together, these results suggest that CXCL14 overexpression attenuates sepsis-associated AKI probably through the downregulation of macrophages-derived cytokine production. However, further studies are required to elucidate the underlying mechanism.

Background. It has been reported that signaling from the nerve growth factor (NGF) pathway associated with peripheral nerves is able to contribute to perineural invasion (PNI) of pancreatic cancer (PC). Nevertheless, the underlying mechanism by which NGF leads to PNI remained poorly understood. Methods. Western blotting was employed to determine NGF level in PC and paracarcinoma tissues and in PC cell lines as well as pancreatic ductal epithelial cells. MiaPaCa-2 and CFPAC-1 cells were treated with 100 ng/ml of NGF or the NGF inhibitor Tanezumab for 24 h, CCK-8 and Transwell assays were employed to test cell proliferation, invasion, and migration, respectively. TrkA expression was knocked down in MiaPaCa-2 and dorsal root ganglion (DRG) cells treated with NGF to determine its effect on the Warburg effect. To reveal that the NGF-TrkA signaling pathway was closely associated with PC PNI, in vitro neuroinvasion model was established by using MiaPaCa-2 cells via coculturing DRG cells in Matrigel. Further, exosomes were extracted from PC cells and identified by examining the levels of specific markers for exosomes. Then RT-qPCR was applied to test miR-21-5p level in tumor derived exosomal (TDE-miR-21-5p). RIP assay was performed to validate NGF and miR-21 binding ability in MiaPaCa-2 cells. Rescue experiments were performed by using coprocessing of Tanezumab and miR-21-5p mimic on MiaPaCa-2 cells, followed by coculture with DRG cells. Subsequently, we used a model of neuroinvasion in nude mice to assess the effect of NGF in vivo on tumor nerve invasion as well as on nociceptive transmission. Results. NGF level was preeminently higher in PC tissues and cell lines than in paracarcinoma tissues and normal pancreatic epithelial cell lines. NGF promoted MiaPaCa-2 and CFPAC-1 cell invasion and migration, while Tanezumab treatment showed the opposite results. Besides, NGF binding to TrkA receptors encouraged the intracellular Warburg effect in PC and DRG cells. TrkA blocking-up could restrain NGF induced PC cell migration and neural invasion. Mechanistically, NGF could upregulate TDE-miR-21-5p levels, and DRG cells took up TDE to activate the Warburg effect and stimulate nociceptor gene expression. miR-21-5p inhibitor could abolish the facilitative effect of NGF on PNI in MiaPaCa-2 cells. In vivo tumorigenesis experiments, Tanezumab markedly alleviated nerve invasion of PC cells as well as relieved nociceptive conduction in animal models. Conclusions. These findings displayed that NGF/TrkA encouraged the neuroinvasive potential of PC cells by activating the Warburg effect in DRG cells through upregulation of TDE-miR-21-5p expression.