ag-490 and Acute-Kidney-Injury

To explore AG490 (the inhibitor of Janus kinase (JAK) 2/signal transducer and activator of transcription (STAT) 3 pathway) in cisplatin (DDP)-induced acute kidney injury (AKI) in mice with lung cancer.. Mice were randomly divided into normal, model, AG490, DDP and DDP + AG490 groups. The lung cancer models were established except for Normal group. The levels of blood urea nitrogen (BUN) and creatinine and the status of oxidative stress were detected. Then, histological changes were assessed by HE and PAS staining and apoptosis by TUNEL experiment. The molecule expressions were detected by qRT-PCR and western blot, and immunohistochemistry, respectively.. DDP inhibited the tumor growth in mice with lung cancer, which was further promoted by the combination with AG490. Mice in the DDP group had elevated levels of BUN and creatinine than those in the Normal group with the increased inflammatory cytokines (TNF-α, IL-6, MCP-1 and CXCL-1) and malondialdehyde (MDA) level and the decreased glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT). In addition, DDP could activate the JAK2/STAT3 pathway to promote the apoptosis by upregulating Bax, cleaved caspase-9 and cleaved caspase-3 while downregulating the Bcl-2 in the kidney tissues. DDP + AG490 group showed the alleviated AKI and the improvements in oxidative stress, inflammatory responses and apoptosis in the kidney tissues, as compared to DDP group.. AG490 alleviated DDP-induced AKI in lung cancer mice with improved oxidative stress and inflammation, and the suppression of JAK2/STAT3 pathway.

Topics: Acute Kidney Injury; Animals; Apoptosis; Blood Urea Nitrogen; Carcinoma, Lewis Lung; Cisplatin; Creatinine; Female; Inflammation; Janus Kinase 2; Lung Neoplasms; Male; Mice; Mice, Inbred C57BL; Oxidative Stress; Signal Transduction; STAT3 Transcription Factor; Tyrphostins

The regeneration of tubular epithelial cells (TECs) after acute kidney injury (AKI) is crucial for the recovery of renal structure and function. The mechanism by which quiescent TECs re-obtain a potential to regenerate remains unknown. In this study, we observed a transient re-expression of embryonic gene Paired box 2 (Pax2) in adult rat TECs in vivo during ischemia-reperfusion induced AKI and most Pax2 positive TECs co-expressed kidney injury molecule-1 (KIM-1), a tubular injury marker. The re-expression of Pax2 was accompanied by increased levels of intrarenal Angiotensin II, which is a crucial injury factor of AKI. Furthermore, we also found a temporary re-expression of Pax2 in NRK-52E cells under the stimulation of Angiotensin II. This stimulatory effect could be blocked by PD123319 (Angiotensin II type 2 receptor (AT2R) inhibitor) and AG490 (Janus Kinase 2 (JAK2) inhibitor). As Pax2 is essential for the phenotypic conversion from mesenchymal stem cells to TECs during kidney development, we proposed that the re-expression of Pax2 in mature TECs may be an indicator of "atavistic" transition which mimics but reverses the processes of development of TECs. This could be proved by that a progenitor marker, CD24, was also found to be transiently expressed shortly after the expression of Pax2 in NRK-52E cells stimulated with Angiotensin II. The expression of CD24 was also suppressed by PD123319 and AG490. Moreover, knockdown of Pax2 by RNA interference could significantly reduce the expression of CD24 in NRK-52E cells stimulated with Angiotension II. Those findings suggest that mature TECs can trans-differentiate into progenitor-like cells by "atavistic transition", which may participate in the recovery of tissue structure and Pax2 may play a pivotal role in this process. That might have important implications for further understanding of tubular regeneration after injury.

Topics: Acute Kidney Injury; Angiotensin II; Animals; Antineoplastic Agents; CD24 Antigen; Cell Line; Epithelial Cells; Gene Expression Regulation; Imidazoles; Janus Kinase 2; Kidney Tubules; PAX2 Transcription Factor; Pyridines; Rats; Reperfusion Injury; Tyrphostins; Vasoconstrictor Agents

Erythropoietin (Epo) induces erythrocytosis by suppressing erythroid progenitor cell apoptosis through the Janus-activated kinase-signal transducers and activators of transcription (JAK-STAT) pathway. Since apoptosis contributes to cisplatin (CP)-induced nephrotoxicity and Epo receptors (EpoR) are expressed in the kidney, we examined the role of antiapoptosis in recombinant human erythropoietin (rHuEpo)-mediated renal protection. In human renal proximal tubular epithelial (RPTE) cells in culture, rHuEpo, but not inactive rHuEpo (I-rHuEpo), the receptor-binding sites of which are mutated, caused a significant reduction in CP-induced apoptosis at > or = 100 U/ml. rHuEpo, but not I-rHuEpo, increased STAT5 and Akt/PKB phosphorylation, demonstrating functional EpoR expression on RPTE cells. Furthermore, the JAK2 inhibitor tyrphostin AG-490 attenuated rHuEpo protection, suggesting a role of the JAK-STAT pathway in rHuEpo-mediated antiapoptosis. In rats, intravenous administration of 5,000 U/kg rHuEpo, but not an equivalent peptide mass of I-rHuEpo, before a single 5.5 mg/kg iv injection of CP, significantly increased hematocrit (Hct) and reduced the CP-induced increase in serum creatinine. Serum creatinine on day 4 was 3.4 +/- 0.3, 1.9 +/- 0.3, and 3.5 +/- 0.4 mg/dl in the CP, CP + rHuEpo, and CP + I-rHuEpo groups, respectively. Similarly, darbepoietin-alpha (DA), a hyperglycosylated analog of rHuEpo with prolonged in vivo activity when injected at 25 microg/kg iv before CP, significantly increased Hct and reduced serum creatinine. Renal clearance studies based on glomerular filtration rate and renal blood flow confirmed the significant renal protection by DA against CP. Tubular apoptosis and necrosis were significantly reduced in the kidneys of the CP + DA vs. the CP + saline group. Moreover, the equalization of Hct by venesection did not abrogate the DA-mediated renal protection. Administration of DA 48 h after CP injection also conferred significant renal protection. Thus our experiments confirm a role for erythropoiesis-stimulating proteins, including the new analog DA, in limiting CP-induced nephrotoxicity and suggest that antiapoptosis via the Epo-EpoR interaction is an important mechanism for renal protection.

Topics: Acute Kidney Injury; Animals; Antineoplastic Agents; Apoptosis; Cells, Cultured; Cisplatin; Darbepoetin alfa; Disease Models, Animal; Enzyme Inhibitors; Erythropoietin; Hematinics; Hematocrit; Humans; Janus Kinase 2; Kidney; Male; Necrosis; Phosphorylation; Proto-Oncogene Proteins c-akt; Rats; Rats, Sprague-Dawley; Receptors, Erythropoietin; Recombinant Proteins; STAT5 Transcription Factor; Tyrphostins