Cpd-A1 alleviates acute kidney injury by inhibiting ferroptosis.

Acute kidney injury (AKI) is defined as sudden loss of renal function characterized by increased serum creatinine levels and reduced urinary output with a duration of 7 days. Ferroptosis, an iron-dependent regulated necrotic pathway, has been implicated in the progression of AKI, while ferrostatin-1 (Fer-1), a selective inhibitor of ferroptosis, inhibited renal damage, oxidative stress and tubular cell death in AKI mouse models. However, the clinical translation of Fer-1 is limited due to its lack of efficacy and metabolic instability. In this study we designed and synthesized four Fer-1 analogs (Cpd-A1, Cpd-B1, Cpd-B2, Cpd-B3) with superior plasma stability, and evaluated their therapeutic potential in the treatment of AKI. Compared with Fer-1, all the four analogs displayed a higher distribution in mouse renal tissue in a pharmacokinetic assay and a more effective ferroptosis inhibition in erastin-treated mouse tubular epithelial cells (mTECs) with Cpd-A1 (N-methyl-substituted-tetrazole-Fer-1 analog) being the most efficacious one. In hypoxia/reoxygenation (H/R)- or LPS-treated mTECs, treatment with Cpd-A1 (0.25 µM) effectively attenuated cell damage, reduced inflammatory responses, and inhibited ferroptosis. In ischemia/reperfusion (I/R)- or cecal ligation and puncture (CLP)-induced AKI mouse models, pre-injection of Cpd-A1 (1.25, 2.5, 5 mg·kg-1·d-1, i.p.) dose-dependently improved kidney function, mitigated renal tubular injury, and abrogated inflammation. We conclude that Cpd-A1 may serve as a promising therapeutic agent for the treatment of AKI.

CHOP-mediated Gasdermin E expression promotes pyroptosis, inflammation, and mitochondrial damage in renal ischemia-reperfusion injury.

In clinical practice, renal ischemia-reperfusion injury (IRI) is a common cause of acute kidney injury (AKI), often leading to acute renal failure or end-stage renal disease (ESRD). The current understanding of renal IRI mechanisms remains unclear, and effective therapeutic strategies and clear targets are lacking. Therefore, the need to find explicit and effective ways to reduce renal IRI remains a scientific challenge. The current study explored pyroptosis, a type of inflammation-regulated programmed cell death, and the role of Gasdermins E (GSDME)-mediated pyroptosis, mitochondrial damage, and inflammation in renal IRI. The analysis of human samples showed that the expression levels of GSDME in normal human renal tissues were higher than those of GSDMD. Moreover, our study demonstrated that GSDME played an important role in mediating pyroptosis, inflammation, and mitochondrial damage in renal IRI. Subsequently, GSDME-N accumulated in the mitochondrial membrane, leading to mitochondrial damage and activation of caspase3, which generated a feed-forward loop of self-amplification injury. However, GSDME knockout resulted in the amelioration of renal IRI. Moreover, the current study found that the transcription factor CHOP was activated much earlier in renal IRI. Inhibition of BCL-2 by CHOP leaded to casapse3 activation, resulting in mitochondrial damage and apoptosis; not only that, but CHOP positively regulated GSDME thereby causing pyroptosis. Therefore, this study explored the transcriptional mechanisms of GSDME during IRI development and the important role of CHOP/Caspase3/GSDME mechanistic axis in regulating pyroptosis in renal IRI. This axis might serve as a potential therapeutic target.

Vaccarin alleviates cisplatin-induced acute kidney injury via decreasing NOX4-derived ROS.

Cisplatin is a chemotherapeutant widely used in treating solid tumors, with the common side effect of acute kidney injury (AKI). Developing effective useful agent for preventing or treating cisplatin-induced AKI is of great importance. In this study, we investigate the protective effect of vaccarin, a chemical entity of flavonoid glycoside, against cisplatin-induced AKI. Cisplatin-treated C57BL/6J mice and human kidney-2 (HK-2) cells were used as the model of cisplatin-induced AKI. The levels of blood urea nitrogen (BUN) and creatine (Cr) levels and periodic acid-Schiff staining (PAS) scores decreased when vaccarin was administrated. Vaccarin had no impact on renal platinum accumulation, which was detected by the ICP-MS 6 h after cisplatin injection. Moreover, vaccarin can significantly alleviate the product of reactive oxygen species and the expression of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 4 (NOX4) in cisplatin-induced AKI, both in vivo and in vitro. In addition, vaccarin decreased the receptor-interacting protein kinase 1 (RIPK1) related programmed necrosis (necroptosis), cell apoptosis (shown by the protein levels of cleaved-caspase3 and flow cytometry) and inflammation (shown by the decreased levels of NLRP3, p-P65 and the mRNA of several inflammatory factors). NOX4 inhibitor GLX351322 (GLX) and NOX4 kowndown by siRNA have equivalent protective effect of vaccarin in vitro. When vaccarin was administered together with GLX or NOX4 siRNA, this protective effect of vaccarin did not further increase, as indicating by the index of oxidative stress, cell viability, necroptosis and apoptosis. In conclusion, vaccarin can alleviate cisplatin-induced AKI via inhibiting NOX4.

Novel insights into STAT3 in renal diseases.

Signal transducer and activator of transcription 3 (STAT3) is a cell-signal transcription factor that has attracted considerable attention in recent years. The stimulation of cytokines and growth factors can result in the transcription of a wide range of genes that are crucial for several cellular biological processes involved in pro- and anti-inflammatory responses. STAT3 has attracted considerable interest as a result of a recent upsurge in study because of their role in directing the innate immune response and sustaining inflammatory pathways, which is a key feature in the pathogenesis of many diseases, including renal disorders. Several pathological conditions which may involve STAT3 include diabetic nephropathy, acute kidney injury, lupus nephritis, polycystic kidney disease, and renal cell carcinoma. STAT3 is expressed in various renal tissues under these pathological conditions. To better understand the role of STAT3 in the kidney and provide a theoretical foundation for STAT3-targeted therapy for renal disorders, this review covers the current work on the activities of STAT3 and its mechanisms in the pathophysiological processes of various types of renal diseases.

Caveolin-1 ameliorates acetaminophen-aggravated inflammatory damage and lipid deposition in non-alcoholic fatty liver disease via the ROS/TXNIP/NLRP3 pathway.

The overuse of acetaminophen (APAP) may cause more severe hepatotoxicity in patients with non-alcoholic fatty liver disease (NAFLD). Caveolin-1 (CAV1), is an essential regulator of metabolic function, which can alleviate liver damage by scavenging reactive oxygen species (ROS). Evidence suggests that the NOD-like receptor family pyrin domain-containing 3 (NLRP3) -mediated pyroptosis is involved in the development of NAFLD. Moreover, thioredoxin-interactive protein (TXNIP) activation is a key event linking ROS to NLRP3 inflammasome. However, whether CAV1 alleviates APAP-aggravated hepatotoxicity in NAFLD via the ROS/TXNIP/NLRP3 pathway remains unclear. An in vivo fatty liver model was established by feeding mice a high-fat diet for 56 days. Additionally, using in vitro approach, AML-12 cells were incubated with free fatty acids for 48 h and APAP was added during the last 24 h. We found that the overuse of APAP in NAFLD not only induced oxidative stress, but also increased TXNIP expression, NLRP3-mediated pyroptosis, and lipid deposition. In addition to inhibiting ROS generation and lipid deposition, overexpression of CAV1 reduced the elevated levels of TXNIP expression and NLRP3-mediated pyroptosis. However, the effect of CAV1 on TXNIP expression, NLRP3-mediated pyroptosis, and lipid deposition was reversed by CAV1 small interfering RNA (siRNA) intervention. Finally, N-acetyl cysteine (NAC) treatment reduced CAV1 siRNA-mediated changes in TXNIP expression and NLRP3-mediated pyroptosis levels. These results demonstrate that the inhibitory effect of CAV1 on NLRP3-mediated pyroptosis may be mediated through the ROS/TXNIP axis. Moreover, the current study provides novel mechanistic insights into the protective effects of CAV1 on APAP-aggravated hepatotoxicity in NAFLD.

Epigallocatechin Gallate Attenuates Gentamicin-Induced Nephrotoxicity by Suppressing Apoptosis and Ferroptosis.

Gentamicin (GEN) is a kind of aminoglycoside antibiotic with the adverse effect of nephrotoxicity. Currently, no effective measures against the nephrotoxicity have been approved. In the present study, epigallocatechin gallate (EG), a useful ingredient in green tea, was used to attenuate its nephrotoxicity. EG was shown to largely attenuate the renal damage and the increase of malondialdehyde (MDA) and the decrease of glutathione (GSH) in GEN-injected rats. In NRK-52E cells, GEN increased the cellular ROS in the early treatment phase and ROS remained continuously high from 1.5 H to 24 H. Moreover, EG alleviated the increase of ROS and MDA and the decrease of GSH caused by GEN. Furthermore, EG activated the protein levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1). After the treatment of GEN, the protein level of cleaved-caspase-3, the flow cytometry analysis and the JC-1 staining, the protein levels of glutathione peroxidase 4 (GPX4) and SLC7A11, were greatly changed, indicating the occurrence of both apoptosis and ferroptosis, whereas EG can reduce these changes. However, when Nrf2 was knocked down by siRNA, the above protective effects of EG were weakened. In summary, EG attenuated GEN-induced nephrotoxicity by suppressing apoptosis and ferroptosis.

Caveolin-1 Alleviates Acetaminophen-Induced Hepatotoxicity in Alcoholic Fatty Liver Disease by Regulating the Ang II/EGFR/ERK Axis.

Acetaminophen (APAP) is a widely used antipyretic analgesic which can lead to acute liver failure after overdoses. Chronic alcoholic fatty liver disease (AFLD) appears to enhance the risk and severity of APAP-induced liver injury, and the level of angiotensin II (Ang II) increased sharply at the same time. However, the underlying mechanisms remain unclear. Caveolin-1 (CAV1) has been proven to have a protective effect on AFLD. This study aimed to examine whether CAV1 can protect the APAP-induced hepatotoxicity of AFLD by affecting Ang II or its related targets. In vivo, the AFLD model was established according to the chronic-plus-binge ethanol model. Liver injury and hepatic lipid accumulation level were determined. The levels of Angiotensin converting enzyme 2 (ACE2), Ang II, CAV1, and other relevant proteins were evaluated by western blotting. In vitro, L02 cells were treated with alcohol and oleic acid mixture and APAP. CAV1 and ACE2 expression was downregulated in APAP-treated AFLD mice compared to APAP-treated mice. The overexpression of CAV1 in mice and L02 cells alleviated APAP-induced hepatotoxicity in AFLD and downregulated Ang II, p-EGFR/EGFR and P-ERK/ERK expression. Immunofluorescence experiments revealed interactions between CAV1, Ang II, and EGFR. The application of losartan (an Ang II receptor antagonist) and PD98059 (an ERK1/2 inhibitor) alleviated APAP-induced hepatotoxicity in AFLD. In conclusion, our findings verified that CAV1 alleviates APAP-aggravated hepatotoxicity in AFLD by downregulating the Ang II /EGFR/ERK axis, which could be a novel therapeutic target for its prevention or treatment.

Insulin-like growth factor binding protein 7 promotes acute kidney injury by alleviating poly ADP ribose polymerase 1 degradation.

The novel biomarker, insulin-like growth factor binding protein 7 (IGFBP7), is used clinically to predict different types of acute kidney injury (AKI) and has drawn significant attention as a urinary biomarker. However, as a secreted protein in the circulation of patients with AKI, it is unclear whether IGFBP7 acts as a key regulator in AKI progression, and if mechanisms underlying its upregulation still need to be determined. Here we found that IGFBP7 is highly expressed in the blood and urine of patients and mice with AKI, possibly via a c-Jun-dependent mechanism, and is positively correlated with kidney dysfunction. Global knockout of IGFBP7 ameliorated kidney dysfunction, inflammatory responses, and programmed cell death in murine models of cisplatin-, kidney ischemia/reperfusion-, and lipopolysaccharide-induced AKI. IGFBP7 mainly originated from kidney tubular epithelial cells. Conditional knockout of IGFBP7 from the kidney protected against AKI. By contrast, rescue of IGFBP7 expression in IGFBP7-knockout mice restored kidney damage and inflammation. IGFBP7 function was determined in vitro using recombinant IGFBP7 protein, IGFBP7 knockdown, or overexpression. Additionally, IGFBP7 was found to bind to poly [ADP-ribose] polymerase 1 (PARP1) and inhibit its degradation by antagonizing the E3 ubiquitin ligase ring finger protein 4 (RNF4). Thus, IGFBP7 in circulation acts as a biomarker and key mediator of AKI by inhibiting RNF4/PARP1-mediated tubular injury and inflammation. Hence, over-activation of the IGFBP7/PARP1 axis represents a promising target for AKI treatment.

The protective effect of rabeprazole on cisplatin-induced apoptosis and necroptosis of renal proximal tubular cells.

Nephrotoxicity is a major adverse reaction of cisplatin-based chemotherapy. Organic cation transporter 2 (OCT2) which is located on the basement membrane of human proximal renal tubules is responsible for the renal accumulation of cisplatin and its nephrotoxicity. This study aimed to investigate the protective effect of PPIs to CP-induced nephrotoxicity. Three kinds of PPIs including lansoprazole, omeprazole and rabeprazole (Rab) were co-administrated with CP to mice. In addition, OCT2-overexpressed HEK293, HK-2 and A549 cells were co-incubated with CP and PPIs. The results showed that PPIs can attenuate CP-induced increase of CRE, BUN and histological damage of kidney. Among the three PPIs, Rab was found with a superior protective effect. It significantly reduced the accumulation of CP in OCT2-overexpressed HEK293 cells and in the renal cortex tissues of mice, but not in HK-2 cells. Moreover, Rab reduced the expression levels of cleaved-caspase-3, RIPK1, RIPK3, MLKL and p-MLKL and the apoptosis rate of renal tubular cells induced by CP in vivo, but not in HK-2 cells. However, Rab increased the viability of CP-treated cells in a concentration-dependent manner and attenuated CP-induced apoptosis and necroptosis in OCT2 over-expressed HEK293 cells. Finally, we demonstrated that Rab have no influence on the antitumor effect of CP. In conclusion, Rab attenuate CP-induced nephrotoxicity mainly through inhibiting OCT2-mediated CP uptake, without interfering with its anti-tumor property of inducing apoptosis and necroptosis.

METTL3-mediated m6A modification of TIMP2 mRNA promotes podocyte injury in diabetic nephropathy.

Epigenetic changes are present in many physiological and pathological processes. The N6-methyladenosine (m6A) modification is the most common modification in eukaryotic mRNA. However, the role of m6A modification in diabetic nephropathy (DN) remains elusive. Here, we found that m6A modification was significantly upregulated in the kidney of type 1 and type 2 diabetic mice, which was caused by elevated levels of METTL3. Moreover, METTL3 is increased in podocyte of renal biopsy from patients with DN, which is related to renal damage. METTL3 knockout significantly reduced the inflammation and apoptosis in high glucose (HG)-stimulated podocytes, while its overexpression significantly aggravated these responses in vitro. Podocyte-conditional knockout METTL3 significantly alleviated podocyte injury and albuminuria in streptozotocin (STZ)-induced diabetic mice. Therapeutically, silencing METTL3 with adeno-associated virus serotype-9 (AAV9)-shMETTL3 in vivo mitigated albuminuria and histopathological injury in STZ-induced diabetic mice and db/db mice. Mechanistically, METTL3 modulated Notch signaling via the m6A modification of TIMP2 in an insulin-like growth factor 2 mRNA binding protein 2 (IGF2BP2)-dependent manner and exerted pro-inflammatory and pro-apoptotic effects. In summary, this study suggested that METTL3-mediated m6A modification is an important mechanism of podocyte injury in DN. Targeting m6A through the writer enzyme METTL3 is a potential approach for the treatment of DN.

Caveolin-1 Alleviates Acetaminophen-Induced Fat Accumulation in Non-Alcoholic Fatty Liver Disease by Enhancing Hepatic Antioxidant Ability via Activating AMPK Pathway.

Non-alcoholic fatty liver disease (NAFLD) is an independent risk factor for acute liver injury caused by overuse of acetaminophen (APAP). Caveolin-1 (CAV1), a regulator of hepatic energy metabolism and oxidative stress, was found to have a protective effect against NAFLD in our previous study. However, it remains unclear whether CAV1 has a protective effect against APAP-induced hepatotoxicity in NAFLD. The aim of this study was to determine whether CAV1 inhibits oxidative stress through the AMPK/Nrf2/HO-1 pathway to protect the liver from fat accumulation exacerbated by APAP in NAFLD. In this study, seven-week-old C57BL/6 male mice (18-20 g) were raised under similar conditions for in vivo experiment. In vitro, L02 cells were treated with A/O (alcohol and oleic acid mixture) for 48 h, and APAP was added at 24 h for further incubation. The results showed that the protein expression of the AMPK/Nrf2 pathway was enhanced after CAV1 upregulation. The effects of CAV1 on fat accumulation, ROS, and the AMPK/Nrf2 anti-oxidative pathway were reduced after the application of CAV1-siRNA. Finally, treatment with compound C (an AMPK inhibitor) prevented CAV1 plasmid-mediated alleviation of oxidative stress and fat accumulation and reduced the protein level of Nrf2 in the nucleus, demonstrating that the AMPK/Nrf2/HO-1 pathway was involved in the protective effect of CAV1. These results indicate that CAV1 exerted a protective effect against APAP-aggravated lipid deposition and hepatic injury in NAFLD by inhibiting oxidative stress. Therefore, the upregulation of CAV1 might have clinical benefits in reducing APAP-aggravated hepatotoxicity in NAFLD.

Rutaecarpine derivative Cpd-6c alleviates acute kidney injury by targeting PDE4B, a key enzyme mediating inflammation in cisplatin nephropathy.

Acute kidney injury (AKI), characterized by a rapid decline in renal function, is triggered by an acute inflammatory response that leads to kidney damage. An effective treatment for AKI is lacking. Using in vitro and in vivo AKI models, our laboratory has identified a series of anti-inflammatory molecules and their derivatives. In the current study, we identified the protective role of rutaecarpine (Ru) on renal tubules. We obtained a series of 3-aromatic sulphonamide-substituted Ru derivatives exhibiting enhanced renoprotective and anti-inflammatory function. We identified Compound-6c(Cpd-6c) as having the best activity and examined its protective effect against cisplatin nephropathy both in vivo and in vitro in cisplatin-stimulated tubular epithelial cells (TECs). Our results showed that Cpd-6c restored renal function more effectively than Ru, as evidenced by reduced blood urea nitrogen and serum creatinine levels in mice. Cpd-6c alleviated tubular injury, as shown by PAS staining and molecular analysis of kidney injury molecule-1 (KIM-1), with both prevention and treatment protocols in cisplatin-treated mice. Moreover, Cpd-6c decreased kidney inflammation, oxidative stress and programmed cell death. These results have also been confirmed in cisplatin-treated TECs. Using web-prediction algorithms, molecular docking, and cellular thermal shift assay (CETSA), we identified phosphodiesterase 4B (PDE4B) as a Cpd-6c target. In addition, we firstly found that PDE4B was up-regulated significantly in the serum of AKI patients. After identifying the function of PDE4B in cisplatin-treated tubular epithelial cells by siRNA transfection or PDE4 inhibitor rolipram, we showed that Cpd-6c treatment did not protect against cisplatin-induced injury in PDE4B knockdown TECs, thus indicating that Cpd-6c exerts its renoprotective and anti-oxidative effects via the PDE4B-dependent pathway. Collectively, Cpd-6c might serve as a potential therapeutic agent for AKI and PDE4B may be highly involved in the initiation and progression of AKI.

Smad3 promotes AKI sensitivity in diabetic mice via interaction with p53 and induction of NOX4-dependent ROS production.

The incidence and severity of acute kidney injury (AKI) is increased yearly in diabetic patients. Although the mechanisms for this remain unclear, the prevention of AKI in diabetic nephropathy is feasible and of value. As we detected highly activation of TGF-ß/Smad3 signaling in both human biopsy and mouse model of diabetic nephropathy, we hypothesized that Smad3 activation in diabetic kidneys may increase AKI sensitivity. We tested our hypothesis in vitro using TGF-ß type II receptor (TGF-ßRII) disrupted tubular epithelial cells (TECs) and in vivo in mice with streptozotocin (STZ)-induced diabetic nephropathy before the induction of ischemia/reperfusion (I/R) injury. We found that high glucose (HG)-cultured TECs showed increased inflammation, apoptosis and oxidative stress following hypoxia/reoxygenation (H/R) injury. Disruption of TGF-ßRII attenuated cell injury induced by H/R in HG-treated TECs. Consistently, Smad3 knockdown in diabetic kidney attenuated I/R-induced AKI. Mechanistically, Smad3 binds to p53 and enhances p53 activity in cells treated with HG and H/R, which may lead to TECs apoptosis. Additionally, ChIP assay showed that Smad3 bound with the promoter region of NOX4 and induced ROS production and inflammation. In conclusion, our results demonstrate that Smad3 promotes AKI susceptibility in diabetic mice by interacting with p53 and NOX4.

Cadmium exposure enhances organic cation transporter 2 trafficking to the kidney membrane and exacerbates cisplatin nephrotoxicity.

Renal accumulation and exposure of cadmium originating from pollution in agricultural land and the prevalence of cigarette smoking remains an unneglectable human health concern. Whereas cadmium exposure has been correlated with increased incidence of a variety of kidney diseases, little is known pertaining to its effect on renal drug disposition and response in patients. Here, we report that cadmium exposure significantly increased the activity of organic cation transporter 2 (OCT2), a critical renal drug transporter recommended in United States Federal Drug Administration guidance for assessment during drug development. Cadmium enhanced OCT2 trafficking to the cell membrane both in vitro and in vivo. Mechanistically cadmium-mediated OCT2 translocation was found to involve protein-protein interaction between serine/threonine-protein kinase AKT2, calcium/calmodulin and the AKT substrate AS160 in in vitro cellular studies. The formed protein complex could selectively facilitate phosphorylation of AKT2 at T309, which induced translocation of OCT2 to the plasma membrane. Moreover, cadmium exposure markedly exacerbated nephrotoxicity induced by cisplatin, an OCT2 substrate, by increasing its accumulation in the mouse kidney. Consistently, there was a significant correlation between plasma cadmium level and alteration of renal function in cervical cancer patients who underwent chemotherapy with cisplatin. Thus, our studies suggest that membrane transporter distribution induced by cadmium exposure is a previously unrecognized factor for the broad variation in renal drug disposition and response.

Alcohol promotes renal fibrosis by activating Nox2/4-mediated DNA methylation of Smad7.

Alcohol consumption causes renal injury and compromises kidney function. The underlying mechanism of the alcoholic kidney disease remains largely unknown. In the present study, an alcoholic renal fibrosis animal model was first employed which mice received liquid diet containing alcohol for 4 to 12 weeks. The Masson's Trichrome staining analysis showed that kidney fibrosis increased at week 8 and 12 in the animal model that was further confirmed by albumin assay, Western blot, immunostaining and real-time PCR of fibrotic indexes (collagen I and α-SMA). In vitro analysis also confirmed that alcohol significantly induced fibrotic response (collagen I and α-SMA) in HK2 tubular epithelial cells. Importantly, both in vivo and in vitro studies showed alcohol treatments decreased Smad7 and activated Smad3. We further determined how the alcohol affected the balance of Smad7 (inhibitory Smad) and Smad3 (regulatory Smad). Genome-wide methylation sequencing showed an increased DNA methylation of many genes and bisulfite sequencing analysis showed an increased DNA methylation of Smad7 after alcohol ingestion. We also found DNA methylation of Smad7 was mediated by DNMT1 in ethyl alcohol (EtOH)-treated HK2 cells. Knockdown of Nox2 or Nox4 decreased DNMT1 and rebalanced Smad7/Smad3 axis, and thereby relieved EtOH-induced fibrotic response. The inhibition of reactive oxygen species by the intraperitoneal injection of apocynin attenuated renal fibrosis and restored renal function in the alcoholic mice. Collectively, we established novel in vivo and in vitro alcoholic kidney fibrosis models and found that alcohol induces renal fibrosis by activating oxidative stress-induced DNA methylation of Smad7. Suppression of Nox-mediated oxidative stress may be a potential therapy for long-term alcohol abuse-induced kidney fibrosis.

Over-Expression of PTEN Suppresses the Proliferation and Migration of Fibroblast-Like Synoviocytes in Adjuvant-Induced Arthritis.

BACKGROUND/AIMS: Rheumatoid arthritis (RA) is characterized by a tumor-like expansion of the synovium and the subsequent destruction of adjacent articular cartilage and bone. Recent studies have shown that phosphatase and tension homolog deleted on chromosome 10 (PTEN) might contribute to the surviva of fibroblast-like synoviocytes (FLSs) and the production of pro-inflammatory cytokines in RA. The purpose of this study was to explore the functions and underlying mechanisms of PTEN in the proliferation and migration of FLSs. METHODS: FLSs were obtained from adjuvant-induced arthritis (AIA) and normal rats. The expression levels of PTEN, c-Myc, cyclin D1, PCNA, and MMP-9 were detected by quantitative-real-time-PCR and western blot assay. A BrdU proliferation assay, cell cycle analysis, and a wound-healing assay were used to study the role of PTEN in FLSs treated with PTEN inhibitor bpv, specific small interfering RNA targeting PTEN (PTEN-RNAi) or a PTEN over-expression vector (PTEN-GV141). Chromatin immunoprecipitation and methylation-special PCR assays were used to study the expression of PTEN mRNA in the presence of DNA methylation. RESULTS: PTEN expression was downregulated in AIA FLSs in comparison to normal rats. Moreover, inhibition of PTEN expression by bpv or PTEN-RNAi could promote the proliferation and migration of FLSs, and increase the expression of c-Myc, cyclin D1, PCNA, and MMP-9 in AIA FLSs, but had no effect on TIMP-1 expression.In addition, transfection of AIA FLSs with PTEN-GV141 reduced their proliferation and migration. Further study indicated that DNA methylation could regulate PTEN expression in AIA. CONCLUSION: Our findings suggest that PTEN might play a pivotal role in the proliferation and migration of FLSs through the activation of the AKT signaling pathway. Additionally, PTEN expression may be regulated by DNA methylation in the pathogenesis of AIA.

hsa-miR-500a-3P alleviates kidney injury by targeting MLKL-mediated necroptosis in renal epithelial cells.

MLKL is a central mediator for necroptosis. Its knockout significantly relieves acute kidney injury (AKI). However, its upstream regulatory mechanism in AKI has not been fully elucidated. We recently reviewed how microRNAs (miRNAs), a type of well-studied epigenetic regulator, play critical roles in AKI. Here, we evaluated miRNAs that potentially target MLKL and evaluated their function in human tubular epithelial cells in response to toxic and ischemic insults. TargetScan analysis showed that miR-194-5P, miR-338-3P, miR-500a-3P, and miR-577 had MLKL binding sites. Although all 4 miRNAs are reduced in AKI, our data show that only hsa-miR-500a-3P was significantly suppressed in cisplatin-treated human tubular epithelial (HK2) cells. We further found that hsa-miR-500a-3P alleviated cisplatin-induced HK2 cell death, which was confirmed by transmission electron microscopy and flow cytometry. In addition, overexpression of hsa-miR-500a-3P decreased kidney injury molecule-1 mRNA and protein levels. Real-time PCR, ELISA, and immunofluorescence data show that hsa-miR-500a-3P protected against inflammatory response, evidenced by decreased monocyte chemotactic protein-1 and proinflammatory cytokines TNF-α and IL-8. Further, hsa-miR-500a-3P attenuated P65 NF-κB phosphorylation and promoter activity. Mechanistically, luciferase reporter assay showed that hsa-miR-500a-3P bound the 3'UTR of MLKL, thereby suppressing phosphorylation and membrane translocation of MLKL. In agreement with these findings, we identified that overexpression of hsa-miR-500a-3P attenuated cell injury and the inflammatory response in response to sodium azide treatment in an in vitro model. Results show that circulating exosomes from patients with AKI down-regulated miR-500a-3P, which suppressed cell injury and inflammation in HK2 cells. hsa-miR-500a-3P alleviated toxic and ischemic insults that were triggered by cell necroptosis and the inflammatory response in human HK2 cells by targeting MLKL. This may serve as a novel therapeutic target for treatment of AKI.-Jiang, L., Liu, X.-Q., Ma, Q., Yang, Q., Gao, L., Li, H.-D., Wang, J.-N., Wei, B., Wen, J., Li, J., Wu, Y.-G., Meng, X.-M. hsa-miR-500a-3P alleviates kidney injury by targeting MLKL-mediated necroptosis in renal epithelial cells.

Nox4 in renal diseases: An update.

Reactive oxygen species derived from NADPH oxidase contribute to a wide variety of renal diseases. Nox4, the major NADPH isoform in kidney, produces mainly H2O2 that regulates physiological functions. Nox4 contributes to redox processes involved in diabetic nephropathy, acute kidney injury, obstructive nephropathy, hypertensive nephropathy, renal cell carcinoma and other renal diseases by activating multiple signaling pathways. Although Nox4 is found in a variety of cell types, including epithelial cells, podocytes, mesangial cells, endothelial cells and fibroblasts, its role is not clear and even controversial. In some conditions, Nox4 protects cells by promoting cell survival in response to harmful stimuli. In other scenarios it induces cell apoptosis, inflammation or fibrogenesis. This functional variability may be attributed to distinct cell types, subcellular localization, molecular concentrations, disease type or stage, and other factors yet unexplored. In this setting, we reviewed the function and mechanism of Nox4 in renal diseases, highlighted the contradictions in Nox4 literature, and discussed promising therapeutic strategies targeting Nox4 in the treatment of certain types of renal diseases.

Metastasis-associated in colon cancer 1: A promising biomarker for the metastasis and prognosis of colorectal cancer.

Colorectal cancer (CRC) is the fourth most frequent type of malignancy in the world. Metastasis accounts for >90% mortalities in patients with CRC. The metastasis-associated in colon cancer 1 (MACC1) gene has been identified as a novel biomarker for the prediction of metastasis and disease prognosis, particularly for patients with early-stage disease. Previous clinical studies demonstrated that MACC1 expression and polymorphisms in CRC tissues were indicators of metastasis, and that circulating transcripts in plasma were also significantly associated with the survival of patients. The present review describes the use of MACC1 beyond its utility in the clinic. By elucidating the upstream and downstream signal pathways of MACC1, the well-known mechanisms of MACC1-mediated cell proliferation, invasion, migration and epithelial-mesenchymal transition (EMT) are summarized, as well as the potential signaling pathways. Furthermore, the underlying mechanisms by which the overexpression of MACC1 causes cisplatin resistance are emphasized.

Aging increases the susceptibility of cisplatin-induced nephrotoxicity.

Cisplatin (CDDP) nephrotoxicity is one of the most common side effects in cancer treatment, causing the disruption of chemotherapy. In this study, we analyzed the influence of nongenetic factors on CDDP-induced nephrotoxiciy using the data from 182 CDDP-treated and 52 carboplatin (CBP)-treated patients. The mean change of eGFR (100% to baseline) in CDDP-treated patients was -9.2%, which was significantly lower than that in the population with CBP therapy. By using the chi-squared test and multivariate logistic regression analysis, age (≥50 years) is found associated with CDDP-induced nephrotoxicity, with odds ratio (OR) of 9.167 and 11.771, respectively. Three- and 18-month-old mice were employed to study the age-dependent susceptibility of CDDP-induced nephrotoxicity. Biochemical parameters, histopathogical examination, and mRNA biomarkers indicated that old mice were subjected to more severe kidney injury. In addition, old mice accumulated more CDDP in kidney than young mice, and the protein level of CDDP efflux transporter, MATE1, in aged mice kidney was 35% of that in young mice. Moreover, inflammatory receptor TLR4 was higher in the kidney of old mice, indicating the alteration of inflammatory signaling in old mice. After CDDP administration, the induced alterations of TNF-α, ICAM-1, and TLR4 were more extensive in old mice. To summarize, aging increased the susceptibility of CDDP-induced renal function decline or nephrotoxicity.