Protective Effects of Growth Arrest-Specific Protein 6 (Gas6) on Sepsis-Induced Acute Kidney Injury

MicroRNAs in septic acute kidney injury

Sepsis is a potentially fatal complication of burns and trauma that can cause acute kidney injury (AKI) with substantial morbidity and mortality, but this disease is poorly understood. Despite medical advances, effective therapeutic regimens for septic AKI remain uncommon. MicroRNAs (miRNAs) are endogenous non-coding RNAs that influence the translation of target messenger RNAs in a variety of biological processes. Emerging evidence has shown that miRNAs are intimately associated with septic AKI. The goal of this review was to summarize recent advances in the profound understanding of the functional role of miRNAs in septic AKI, as well as to provide new insights into miRNAs as feasible biomarkers and therapeutic targets for septic AKI.

Urinary proteome analysis of acute kidney injury in post-cardiac surgery patients using enrichment materials with high-resolution mass spectrometry

Background: Cardiac surgery-associated acute kidney injury (CSA-AKI) may increase the mortality and incidence rates of chronic kidney disease in critically ill patients. This study aimed to investigate the underlying correlations between urinary proteomic changes and CSA-AKI.

Methods: Nontargeted proteomics was performed using nano liquid chromatography coupled with Orbitrap Exploris mass spectrometry (MS) on urinary samples preoperatively and postoperatively collected from patients with CSA-AKI. Gemini C18 silica microspheres were used to separate and enrich trypsin-hydrolysed peptides under basic mobile phase conditions. Differential analysis was conducted to screen out urinary differential expressed proteins (DEPs) among patients with CSA-AKI for bioinformatics. Kyoto Encyclopedia of Genes and Genomes (KEGG) database analysis was adopted to identify the altered signal pathways associated with CSA-AKI.

Results: Approximately 2000 urinary proteins were identified and quantified through data-independent acquisition MS, and 324 DEPs associated with AKI were screened by univariate statistics. According to KEGG enrichment analysis, the signal pathway of protein processing in the endoplasmic reticulum was enriched as the most up-regulated DEPs, and cell adhesion molecules were enriched as the most down-regulated DEPs. In protein–protein interaction analysis, the three hub targets in the up-regulated DEPs were α-1-antitrypsin, β-2-microglobulin and angiotensinogen, and the three key down-regulated DEPs were growth arrest-specific protein 6, matrix metalloproteinase-9 and urokinase-type plasminogen activator.

Conclusion: Urinary protein disorder was observed in CSA-AKI due to ischaemia and reperfusion. The application of Gemini C18 silica microspheres can improve the protein identification rate to obtain highly valuable resources for the urinary DEPs of AKI. This work provides valuable knowledge about urinary proteome biomarkers and essential resources for further research on AKI.

Inhibition of Gas6 promotes crystalline silica-induced inflammatory response of macrophages via blocking autophagy flux

Inhalation of crystalline silica (CS) can cause silicosis, which is one of the most serious interstitial lung diseases worldwide. Autophagy dysfunction is an essential step in silicosis progression. In this study, we aim to identify the effect of growth arrest-specific protein 6 (Gas6) during autophagy induction and macrophage inflammatory response caused by CS. After RAW 264.7 macrophages exposed to CS, the levels of Gas6 and autophagy markers (p62, Beclin1, and LC3-II/LC3-I) were increased, accompanied with enhanced inflammatory cytokines secretion. Using autophagy activator (rapamycin) repressed, whereas autophagy inhibitor (3-methyladenine) promoted inflammatory cytokines release. Besides, inhibition of Gas6 aggravated CS-induced inflammatory response, and autophagy inhibition facilitated the promoted effect of Gas6 silencing, resulting in elevated expression of inflammatory cytokines. These findings reveal the protective effects of Gas6 and autophagy in macrophages in response to CS exposure, and highlight the autophagy regulated by Gas6 may be a potential prevention target for CS-induced lung inflammatory response.

Inhibition of microRNA-665 Alleviates Septic Acute Kidney Injury by Targeting Bcl-2

Sepsis can easily cause acute kidney injury (AKI) and seriously endanger human health. This article aims to investigate and study the role of microRNA-665 (miR-665) in septic AKI and the underlying molecular mechanism. Lipopolysaccharide (LPS) was used to construct cell and animal models of septic AKI. The expression of miR-665 in cells and kidney tissues was detected by quantitative reverse-transcription polymerase chain reaction (RT-PCR). The contents of inflammatory factors (TNF-α, IL-1β, and IL-6) in the cell supernatant were detected using commercial kits. Renal tissue damage was observed by hematoxylin-eosin (HE) staining. Kidney function was assessed by serum Cr, serum BUN, and urine NAG levels. The apoptosis of HK-2 cells was analyzed by flow cytometry and TUNEL staining. Luciferase activity assay was performed for the verification of the target of miR-665. The expression of miR-665 was increased in the cell model and animal model of septic AKI constructed by LPS. By transfecting miR-665 inhibitor in HK-2 cells and injecting miR-665 antagomir (antagomiR-665) through the tail vein of rats, the expression of miR-665 in HK-2 cells and rat kidneys was remarkably reduced. Silencing miR-665 dramatically inhibited the expression of inflammatory factors (TNF-α, IL-1β, and IL-6) in LPS-induced HK-2 cells and reduced LPS-induced apoptosis in HK-2 cells. At the same time, the levels of serum Cr, serum BUN, and urine NAG decreased markedly, and the damage of the kidney was also alleviated. Finally, luciferase reporter experiments demonstrated that miR-665 directly targets Bcl-2. We revealed that miR-665 expression was increased in septic AKI, and silencing miR-665 could inhibit LPS-induced inflammation and apoptosis of the kidney by targeting Bcl-2, thereby improving renal function.

Bioprotective and Functional Effect of Carnosine on Sepsis Induced Renal Damage in Male Albino Rat Model through Targeting IL-1β and TNF-α Production

Acute kidney injury (AKI), one of the frequently diagnosed and serious sepsis induced complication has high morbidity and mortality. The present study investigated the bioprotective and functional effect of carnosine on AKI induced pathological damage in Male Albino rat model in vivo. AKI in Albino rats was induced by cecal ligation and puncture surgery where as TNF-α and IL-1β levels were detected using ELISA assay. Protein expression was examined by western blotting and pathological damage using hematoxylin and eosin (H&E). Treatment with carnosine suppressed AKI induced urea nitrogen and creatinine in Male Albino rat serum in dose-dependent manner. Development of sepsis mediated renal injury in Albino rats was also effectively prevented on treatment with carnosine. Secretion of AKI-induced IL-1β, IL-18, and TNF-α in renal tissues was alleviated significantly in Albino rats by carnosine treatment. Additionally, in carnosine-treated Albino rats renal tissues AKI induced Bax expression was alleviated while as Bcl-2 was promoted compared to AKI Albino rats. Carnosine treatment improved the survival rate of the Albino rats with AKI. Carnosine inhibits renal tissue damage and increases survival rate in AKI Albino rat model. The mechanism involves alleviation of inflammatory cytokine secretion and promotion of Bcl-2 expression. Thus, carnosine may be used as a therapeutic agent for treatment of AKI.

Resolving inflammation by TAM receptor activation

The control of inflammation is strictly regulated to ensure the adequate intensity and duration of an inflammatory response, enabling the removal of the trigger factors and the restoration of the integrity of the tissues and their functions. This process is coordinated by anti-inflammatory and pro-resolving mediators that regulate the cellular and molecular events necessary to restore homeostasis, and defects in this control are associated with the development of chronic and autoimmune diseases. The TAM family of receptor tyrosine kinases-Tyro3, Axl, and MerTK-plays an essential role in efferocytosis, a key process for the resolution of inflammation. However, new studies have demonstrated that TAM receptor activation not only reduces the synthesis of pro-inflammatory mediators by different cell types in response to some stimuli but also stimulates the production of anti-inflammatory and pro-resolving molecules that control the inflammation. This review provides a comprehensive view of TAM receptor family members as important players in controlling inflammatory responses through anti-inflammatory and pro-resolving actions.

Renal Tissue Damage Induced by Acute Kidney Injury in Sepsis Rat Model Is Inhibited by Cynaropicrin via IL-1β and TNF-α Down-Regulation

Acute kidney injury (AKI), one of the frequently diagnosed and serious sepsis induced complication has high morbidity and mortality. The present study investigated the effect of cynaropicrin on AKI induced pathological damage in rat model in vivo. Treatment with cynaropicrin suppressed AKI induced urea nitrogen and creatinine in the rat serum in dose-dependent manner. Development of sepsis mediated renal injury in rats was also effectively prevented on treatment with cynaropicrin. Secretion of AKI-induced IL-1β and TNF-α in renal tissues was alleviated significantly in rats by cynaropicrin treatment. Additionally, in cynaropicrin-treated rats renal tissues AKI induced Bax expression was alleviated while as Bcl-2 was promoted compared to AKI rats. Cynaropicrin treatment improved the survival rate of the rats with AKI. Cynaropicrin inhibits renal tissue damage and increase survival rate in AKI rat model. The mechanism involves alleviation of inflammatory cytokine secretion and promotion of Bcl‑2 expression. Thus, cynaropicrin may be used as therapeutic agent for treatment of AKI.

Growth Arrest-Specific Gene 6 Administration Ameliorates Sepsis-Induced Organ Damage in Mice and Reduces ROS Formation In Vitro

Sepsis is a widespread life-threatening disease, with a high mortality rate due to inflammation-induced multiorgan failure (MOF). Thus, new effective modulators of the immune response are urgently needed to ameliorate the outcome of septic patients. As growth arrest-specific gene 6 (Gas6)/Tyro3, Axl, MerTK (TAM) receptors signaling has shown immunomodulatory activity in sepsis, here we sought to determine whether Gas6 protein injection could mitigate MOF in a cecal slurry mouse model of sepsis. Mice, divided into different groups according to treatment-i.e., placebo (B), ampicillin (BA), Gas6 alone (BG), and ampicillin plus Gas6 (BAG)-were assessed for vitality, histopathology and cytokine expression profile as well as inducible nitric oxide synthase (iNOS), ALT and LDH levels. BAG-treated mice displayed milder kidney and lung damage and reduced levels of cytokine expression and iNOS in the lungs compared to BA-treated mice. Notably, BAG-treated mice showed lower LDH levels compared to controls. Lastly, BAG-treated cells of dendritic, endothelial or monocytic origin displayed reduced ROS formation and increased cell viability, with a marked upregulation of mitochondrial activity. Altogether, our findings indicate that combined treatment with Gas6 and antibiotics ameliorates sepsis-induced organ damage and reduces systemic LDH levels in mice, suggesting that Gas6 intravenous injection may be a viable therapeutic option in sepsis.

Role of emerging vitamin K‑dependent proteins: Growth arrest‑specific protein 6, Gla‑rich protein and periostin (Review)

Vitamin K‑dependent proteins (VKDPs) are a group of proteins that need vitamin K to conduct carboxylation. Thus far, scholars have identified a total of 17 VKDPs in the human body. In this review, we summarize three important emerging VKDPs: Growth arrest‑specific protein 6 (Gas 6), Gla‑rich protein (GRP) and periostin in terms of their functions in physiological and pathological conditions. As examples, carboxylated Gas 6 and GRP effectively protect blood vessels from calcification, Gas 6 protects from acute kidney injury and is involved in chronic kidney disease, GRP contributes to bone homeostasis and delays the progression of osteoarthritis, and periostin is involved in all phases of fracture healing and assists myocardial regeneration in the early stages of myocardial infarction. However, periostin participates in the progression of cardiac fibrosis, idiopathic pulmonary fibrosis and airway remodeling of asthma. In addition, we discuss the relationship between vitamin K, VKDPs and cancer, and particularly the carboxylation state of VKDPs in cancer.

Therapeutic aspects of the Axl/Gas6 molecular system

Axl receptor tyrosine kinase (RTK) and its ligand, growth arrest-specific protein 6 (Gas6), are involved in several biological functions and participate in the development and progression of a range of malignancies and autoimmune disorders. In this review, we present this molecular system from a drug discovery perspective, highlighting its therapeutic implications and challenges that need to be addressed. We provide an update on Axl/Gas6 axis biology, exploring its role in fields ranging from angiogenesis, cancer development and metastasis, immune response and inflammation to viral infection. Finally, we summarize the molecules that have been developed to date to target the Axl/Gas6 molecular system for therapeutic and diagnostic applications.

Effect of ATM on inflammatory response and autophagy in renal tubular epithelial cells in LPS-induced septic AKI

The aim of the present study was to explore the role of ataxia-telangiectasia mutated (ATM) in lipopolysaccharide (LPS)-induced in vitro model of septic acute kidney injury (AKI) and the association between ATM, tubular epithelial inflammatory response and autophagy. The renal tubular epithelial cell HK-2 cell line was cultured and passaged, with HK-2 cell injury induced by LPS. The effects of LPS on HK-2 cell morphology, viability, ATM expression and inflammation were observed. Lentiviral vectors encoding ATM shRNA were constructed to knock down ATM expression in HK-2 cells. The efficiency of ATM knockdown in HK-2 cells was detected by western blot analysis and reverse transcription-quantitative PCR (RT-qPCR). HK-2 cells transfected with the ATM shRNA lentivirus were used for subsequent experiments. Following ATM knockdown, corresponding controls were set up, and the effects of ATM on inflammation and autophagy were detected in HK-2 cells using RT-qPCR, western blotting and ELISA. After LPS stimulation, the HK-2 cells were rounded into a slender or fusiform shape with poorly defined outlines. LPS treatment reduced cell viability in a partly dose-dependent manner. LPS increased the expression of tumor necrosis factor-α, interleukin (IL)-1β and IL-6, with the levels reaching its highest value at 10 µg/ml. IL-6 and IL-1β expression increased with increasing LPS concentration. These findings suggest that LPS reduced HK-2 cell viability whilst increasing the expression of inflammatory factors. Following transfection with ATM shRNA, expression levels of key autophagy indicators microtubule associated protein 1 light chain 3α I/II ratio and beclin-1 in the two ATM shRNA groups were also significantly reduced compared with the NC shRNA group. In summary, downregulation of ATM expression in HK-2 cells reduced LPS-induced inflammation and autophagy in sepsis-induced AKI in vitro, suggesting that LPS may induce autophagy in HK-2 cells through the ATM pathway leading to the upregulation of inflammatory factors.

Gas6/TAM Axis in Sepsis: Time to Consider Its Potential Role as a Therapeutic Target

Tyrosine kinase receptors are transmembrane proteins involved in cell signaling and interaction. Among them, the TAM family (composed by Tyro 3, Axl, and Mer) represents a peculiar subgroup with an important role in many physiological and pathological conditions. Despite different mechanisms of activation (e.g., protein S and Galactin-3), TAM action is tightly related to their common ligand, a protein named growth arrest-specific 6 (Gas6). Since the expression of both TAM and Gas6 is widely distributed among tissues, any alteration of one of these components can lead to different pathological conditions. Moreover, as they are indispensable for homeostasis maintenance, in recent years a growing interest has emerged regarding their role in the regulation of the inflammatory process. Due to this involvement, many authors have demonstrated the pivotal role of the Gas6/TAM axis in both sepsis and the sepsis-related inflammatory responses. In this narrative review, we highlight the current knowledge as well as the last discoveries on TAM and Gas6 implication in different clinical conditions, notably in sepsis and septic shock. Lastly, we underline not only the feasible use of Gas6 as a diagnostic and prognostic biomarker in certain systemic acute conditions but also its potential therapeutic role in these life-threatening diseases.

Gas6 attenuates lipopolysaccharide‑induced TNF‑α expression and apoptosis in H9C2 cells through NF‑κB and MAPK inhibition via the Axl/PI3K/Akt pathway

Therapeutic agents used to treat sepsis‑induced cardiac dysfunction are designed to suppress tumor necrosis factor (TNF)‑α release and inhibit cell apoptosis. Exogenous administration of growth arrest‑specific 6 (Gas6) exerts several biological and pharmacological effects; however, the role of Gas6 in sepsis‑induced myocardial dysfunction remains unclear. In this study, H9C2 cardiomyocytes were stimulated with LPS (10 µg/ml) to mimic septic cardiac dysfunction and Gas6 (100 ng/ml) was applied exogenously. Subsequently, mitogen‑activated protein kinase (MAPK) and nuclear factor (NF)‑κB activation, TNF‑α expression, and apoptosis in the presence or absence of TP‑0903 (15 nM) and Wortmannin (3 nM) were evaluated. The morphological alterations of H9C2 cells were visualized by phase‑contrast microscopy. Cell viability was determined using the Cell Counting kit 8 assay and lactate dehydrogenase release, and TNF‑α release was analyzed by ELISA analysis. Cell apoptosis was analyzed by flow cytometry and TUNEL assay. Nuclear morphological alterations were detected by Hoechst staining and caspase‑3 activity was measured using biochemical methods. The expression levels of Bax and Bcl‑2, and the phosphorylation and expression levels of Axl, Akt, IκB‑α, p65, c‑Jun N‑terminal protein kinase (JNK), extracellular signal‑regulated kinase (ERK) and p38 were determined by western blotting. Furthermore, immunofluorescence analysis was performed to visualize translocation of NF‑κB p65. The results demonstrated that Gas6 suppressed TNF‑α release and inhibited cell apoptosis, and attenuated nuclear factor (NF)‑κB and mitogen‑activated protein kinase (MAPK) activation via the Axl/PI3K/Akt pathway. Furthermore, the cardioprotective properties of Gas6 on the suppression of LPS‑induced TNF‑α release and apoptosis were abolished by treatment with TP‑0903 (an Axl inhibitor) and Wortmannin (a PI3K inhibitor). Pretreatment with TP‑0903 and Wortmannin abrogated the effects of Gas6 on phosphorylated‑IκB‑α, IκB‑α, NF‑κB, ERK1/2, JNK and p38 MAPK. These findings suggested that activation of Axl/PI3K/Akt signaling by Gas6 may inhibit LPS‑induced TNF‑α expression and apoptosis, as well as MAPK and NF‑κB activation.

Gas6 Attenuates Sepsis-Induced Tight Junction Injury and Vascular Endothelial Hyperpermeability via the Axl/NF-κB Signaling Pathway

Vascular endothelial functional dysregulation and barrier disruption are involved the initiation and development of sepsis. Growth arrest-specific protein 6 (Gas6), one of the endogenous ligands of TAM receptors (Tyro3, Axl, and Mertk), is confirmed to have beneficial functions in hemostasis, inflammation, and cancer growth. Here, we demonstrated the protective effects of Gas6 on multi-organ dysfunction syndrome (MODS) in sepsis and the underlying mechanisms. We investigated Gas6-ameliorated MODS by inhibiting vascular endothelial hyperpermeability in a mouse model of sepsis. Additionally, in vitro, under lipopolysaccharide (LPS) stimulation in vascular endothelial cells, Gas6 attenuated vascular endothelial hyperpermeability by reinforcing the tight junction proteins occludin, zonula occludens-1 (ZO-1), and claudin5. Furthermore, Gas6 substantially suppressed NF-κB p65 activation. In addition, blocking the Gas6 receptor, Axl, partially reduced the protective effect of Gas6 on the vascular endothelial barrier and diminished the inhibitive effect of Gas6 on NF-κB p65 activation. Taken together, this study suggests that Gas6 has a protective effect on MODS in sepsis by inhibiting the vascular endothelial hyperpermeability and alteration of tight junction and that the Axl/NF-κB signaling pathway underlies these effects.

Poricoic acid A enhances melatonin inhibition of AKI-to-CKD transition by regulating Gas6/AxlNFκB/Nrf2 axis

Renal ischemia-reperfusion injury (IRI) is a complex syndrome, which causes chronic kidney disease (CKD) after recovery from IRI-mediated acute kidney injury (AKI). There is no single therapy that could effectively prevent the renal injury after ischemia. In this study, the effects of melatonin or poricoic acid A (PAA) and their combination were investigated in protecting against AKI-to-CKD transition in rats and hypoxia/reoxygenation (H/R)-induced injury in cultured renal NRK-52E cells. Melatonin and PAA significantly reduced the magnitude of rise in serum creatinine and urea levels in IRI rats at days 3 and 14. Our results further showed that treatment with melatonin and PAA ameliorated renal fibrosis and podocyte injury by attenuating oxidative stress and inflammation via regulation of nuclear factor-kappa B (NF-κB) and nuclear factor-erythroid-2-related factor 2 (Nrf2) pathways in IRI rats. Melatonin and PAA protected against AKI-to-CKD transition by regulating growth arrest-specific 6 (Gas6)/AxlNFκB/Nrf2 signaling cascade. Melatonin and PAA initiallyupregulated Gas6/Axl signaling to reduce oxidative stress and inflammation in AKI and subsequently downregulated Gas6/Axl signaling to attenuate renal fibrosis and progression to CKD. Melatonin and PAA inhibited expression of extracellular matrix proteins. Poricoic acid A enhances melatonin-mediated inhibition of AKI-to-CKD transition by the regulating Gas6/AxlNFκB/Nrf2 signaling cascade. Notably, our study first identified Axl as a promising therapeutic target for prevention of AKI-to-CKD transition.

Vitamin K Dependent Proteins in Kidney Disease

Patients with chronic kidney disease (CKD) have an increased risk of developing vascular calcifications, as well as bone dynamics impairment, leading to a poor quality of life and increased mortality. Certain vitamin K dependent proteins (VKDPs) act mainly as calcification inhibitors, but their involvement in the onset and progression of CKD are not completely elucidated. This review is an update of the current state of knowledge about the relationship between CKD and four extrahepatic VKDPs: matrix Gla protein, osteocalcin, growth-arrest specific protein 6 and Gla-rich protein. Based on published literature in the last ten years, the purpose of this review is to address fundamental aspects about the link between CKD and circulating VKDPs levels as well as to raise new topics about how the interplay between molecular weight and charge could influence the modifications of circulating VKDPs at the glomerular level, or whether distinct renal etiologies have effect on VKDPs. This review is the output of a systematic literature search and may open future research avenues in this niche domain.

Protective Effects of a Rho Kinase Inhibitor on Paraquat-Induced Acute Lung Injuries in Rats

Fasudil, a rock kinase inhibitor, can inhibit systemic inflammation and prevent paraquat (PQ)-induced acute lung injuries in rats; however, the mechanisms for these protective effects remain elusive. This study investigated how the Rho/ROCK signaling pathway enables fasudil to protect against acute lung injuries in PQ-treated rats. Wistar rats (n = 240) were pretreated with fasudil (10 and 30 mg/kg, i.p.) 1 h prior to PQ administration. When compared to rats with PQ-induced lung injuries, rats pretreated with fasudil had significantly fewer polymorphonuclear neutrophils and lower concentrations of protein, TNF-α, IL-1β, and IL-6 in their bronchoalveolar lavage fluid. Moreover, fasudil also reduced the Evans Blue content, wet-to-dry weight ratio, lung injury scores, and levels malondialdehyde and 8-hydroxy-2 deoxyguanosine, but increased superoxide dismutase activity in lung tissue. Furthermore, Rho, ROCK1 expression and the levels of phosphorylated MYPT-1 in lung tissues were drastically decreased in fasudil-treated rats, whereas ZO-1 protein expression was significantly increased (p < 0.05). We found that fasudil downregulated bax and activated caspase-3 mRNA expression but upregulated Bcl-2 mRNA expression. In vitro experiments showed that the levels of TNF-α, IL-1β, and IL-6 secreted by human pulmonary microvascular endothelial cells treated with PQ were attenuated by fasudil. Fasudil inhibited the upregulation Rho and ROCK protein expression and downregulation of ZO-1 protein expression in HPMVECs induced with PQ. Higher concentrations of fasudil produced greater affects than lower concentrations. Fasudil improved endothelial permeability and inhibited inflammation, oxidative stress, and cell apoptosis to alleviate acute lung injuries in PQ-treated rats. Fasudil exerted these therapeutic effects by inhibiting the Rho/ROCK signaling pathway.

Role of the Rho/ROCK signaling pathway in the protective effects of fasudil against acute lung injury in septic rats

Fasudil, which is primarily prescribed to treat cerebral vasospasm, may also inhibit systemic inflammation and prevent sepsis-induced acute lung injury (ALI) in rats, although the mechanisms remain elusive. The purpose of the present study was to investigate the role of the rhodopsin (Rho)/Rho-associated protein kinase (ROCK) signaling pathway in the protective effects of fasudil on ALI in septic rats. A total of 60 Wistar rats were pretreated with fasudil (30 mg/kg) through intraperitoneal injections 1 h prior to cecal ligation and puncture. Administration of fasudil led to reductions in polymorphonuclear neutrophil counts, and the protein concentrations of tumor necrosis factor-α, interleukin (IL)-1β and IL-6 in the bronchoalveolar lavage fluid of rats with sepsis-induced ALI. The results demonstrated that fasudil decreased sepsis-induced bacteremia. In addition, fasudil effectively reduced the Evans blue content, wet/dry lung weight ratio, lung injury score, and expression levels of malondialdehyde and myeloperoxidase. However, the superoxide dismutase activity in the lung tissue of the rats was increased. Activated caspase-3 activity in lung tissue was reduced to 29% by fasudil. Furthermore, the expression of Rho and ROCK1 was significantly downregulated, and the phosphorylation of myosin phosphatase-targeting subunit 1 in lung tissues was markedly decreased, whereas the protein expression levels of zonula occludens 1 were increased in fasudil-treated rats (P<0.05). In the in vitro experiments, vascular endothelial growth factor, intracellular adhesion molecule 1 and vascular cell adhesion molecule 1 secreted from human pulmonary microvascular endothelial cells treated with lipopolysaccharide (LPS) were attenuated by fasudil. Fasudil also reduced the fluorescence intensity of filamentous actin induced by LPS. Taken together, the results of the present study demonstrated that fasudil was able to improve endothelial permeability and inhibit inflammation, oxidative stress and cellular apoptosis in order to alleviate ALI in septic rats through inhibition of the Rho/ROCK signaling pathway.

Klotho ameliorates sepsis-induced acute kidney injury but is irrelevant to autophagy

Background

The role of Klotho (KL) in sepsis-induced acute kidney injury (AKI) and the potential relationship between KL and autophagy in septic AKI were investigated.

Materials and methods

A murine model of sepsis-induced AKI was established by cecal ligation and puncture (CLP). Mice undergoing CLP and immortalized proximal tubular epithelial human HK-2 cells that were exposed to lipopolysaccharide (LPS) were treated with recombinant KL, autophagy stimulator rapamycin (Rap), and autophagy suppressor 3-methyladenine (3-MA).

Results

Autophagy activation and KL reduction reached maximum levels in mice 24 hours after CLP. Recombinant KL and/or Rap significantly attenuated CLP-induced renal dysfunction (P<0.05) and partially restored endogenous renal KL expression (P<0.05). Recombinant KL had no impact on CLP-induced autophagy and apoptosis, whereas Rap significantly stimulated autophagy and reduced apoptosis in mice. 3-MA significantly exacerbated renal dysfunction, increased apoptosis, and inhibited autophagy in mice with CLP-induced AKI (all P<0.05). In LPS-treated HK-2 cells, Rap significantly enhanced autophagy and reduced apoptosis (all P<0.05), whereas recombinant KL had no impact, and 3-MA inhibited autophagy and significantly increased apoptosis (P<0.05).

Conclusion

Recombinant KL alleviates renal dysfunction and restores renal KL expression in mice with sepsis-induced AKI, but the underlying mechanism may not be related to autophagy induction.

Pterostilbene attenuates acute kidney injury in septic mice

Acute kidney injury (AKI) is a severe complication of sepsis with a high mortality and morbidity. Pterostilbene (Pte) has been suggested to confer anti-apoptotic and anti-inflammatory effects. In the current study, the effects of Pte on AKI were evaluated in septic mice. Cecal ligation and puncture surgery was performed to induce sepsis. The results suggested that Pte administration significantly decreased the levels of serum urea nitrogen and creatinine, and improved the survival rate of septic mice. Additionally, the renal injury induced by sepsis was attenuated by pterostilbene treatment. Notably, pterostilbene reduced Bcl-2-associated X protein expression, and levels of interleukin-1β and tumor necrosis factor-α, and upregulated B-cell lymphoma 2 expression. The results indicate that pterostilbene may serve as a potential therapeutic candidate for the treatment of AKI induced by sepsis.