Novel in vivo imaging techniques to visualise renal morphology and function in acute kidney injury

Acute kidney injury (AKI) following Eastern Russell’s viper (Daboia siamensis) envenoming is a significant symptom in systemically envenomed victims. A number of venom components have been identified as causing the nephrotoxicity which leads to AKI. However, the precise mechanism of nephrotoxicity caused by these toxins is still unclear. In the present study, we purified two proteins from D. siamensis venom, namely RvPLA2 and RvMP. Protein identification using LCMS/MS confirmed the identity of RvPLA2 to be snake venom phospholipase A2 (SVPLA2) from Thai D. siamensis venom, whereas RvMP exhibited the presence of a factor X activator with two subunits. In vitro and in vivo pharmacological studies demonstrated myotoxicity and histopathological changes of kidney, heart, and spleen. RvPLA2 (3–10 µg/mL) caused inhibition of direct twitches of the chick biventer cervicis muscle preparation. After administration of RvPLA2 or RvMP (300 µg/kg, i.p.) for 24 h, diffuse glomerular congestion and tubular injury with minor loss of brush border were detected in envenomed mice. RvPLA2 and RvMP (300 µg/kg; i.p.) also induced congestion and tissue inflammation of heart muscle as well as diffuse congestion of mouse spleen. This study showed the significant roles of PLA2 and SVMP in snake bite envenoming caused by Thai D. siamensis and their similarities with observed clinical manifestations in envenomed victims. This study also indicated that there is a need to reevaluate the current treatment strategies for Thai D. siamensis envenoming, given the potential for irreversible nephrotoxicity.

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RIP3 impedes transcription factor EB to suppress autophagic degradation in septic acute kidney injury

Cell Death and Disease ◽

10.1038/s41419-021-03865-8 ◽

2021 ◽

Vol 12 (6) ◽

Author(s):

Ruizhao Li ◽

Xingchen Zhao ◽

Shu Zhang ◽

Wei Dong ◽

Li Zhang ◽

...

Keyword(s):

Acute Kidney Injury ◽

Transcription Factor ◽

Nuclear Translocation ◽

Kidney Injury ◽

Septic Acute Kidney Injury ◽

Transcription Factor Eb ◽

Autophagic Degradation ◽

Lps Treatment

AbstractAutophagy is an important renal-protective mechanism in septic acute kidney injury (AKI). Receptor interacting protein kinase 3 (RIP3) has been implicated in the renal tubular injury and renal dysfunction during septic AKI. Here we investigated the role and mechanism of RIP3 on autophagy in septic AKI. We showed an activation of RIP3, accompanied by an accumulation of the autophagosome marker LC3II and the autophagic substrate p62, in the kidneys of lipopolysaccharide (LPS)-induced septic AKI mice and LPS-treated cultured renal proximal tubular epithelial cells (PTECs). The lysosome inhibitor did not further increase the levels of LCII or p62 in LPS-treated PTECs. Moreover, inhibition of RIP3 attenuated the aberrant accumulation of LC3II and p62 under LPS treatment in vivo and in vitro. By utilizing mCherry-GFP-LC3 autophagy reporter mice in vivo and PTECs overexpression mRFP-GFP-LC3 in vitro, we observed that inhibition of RIP3 restored the formation of autolysosomes and eliminated the accumulated autophagosomes under LPS treatment. These results indicated that RIP3 impaired autophagic degradation, contributing to the accumulation of autophagosomes. Mechanistically, the nuclear translocation of transcription factor EB (TFEB), a master regulator of the lysosome and autophagy pathway, was inhibited in LPS-induced mice and LPS-treated PTECs. Inhibition of RIP3 restored the nuclear translocation of TFEB in vivo and in vitro. Co-immunoprecipitation further showed an interaction of RIP3 and TFEB in LPS-treated PTECs. Also, the expression of LAMP1 and cathepsin B, two potential target genes of TFEB involved in lysosome function, were decreased under LPS treatment in vivo and in vitro, and this decrease was rescued by inhibiting RIP3. Finally, overexpression of TFEB restored the autophagic degradation in LPS-treated PTECs. Together, the present study has identified a pivotal role of RIP3 in suppressing autophagic degradation through impeding the TFEB-lysosome pathway in septic AKI, providing potential therapeutic targets for the prevention and treatment of septic AKI.

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α2-Adrenoceptor agonist dexmedetomidine protects septic acute kidney injury through increasing BMP-7 and inhibiting HDAC2 and HDAC5

AJP Renal Physiology ◽

10.1152/ajprenal.00143.2012 ◽

2012 ◽

Vol 303 (10) ◽

pp. F1443-F1453 ◽

Cited By ~ 46

Author(s):

Chung-Hsi Hsing ◽

Chiou-Feng Lin ◽

Edmund So ◽

Ding-Ping Sun ◽

Tai-Chi Chen ◽

...

Keyword(s):

Acute Kidney Injury ◽

Histone Deacetylases ◽

Trichostatin A ◽

Histone H3 ◽

Cecal Ligation ◽

Kidney Injury ◽

Protective Effects ◽

Tnf Α

Bone morphogenetic protein (BMP)-7 protects sepsis-induced acute kidney injury (AKI). Dexmedetomidine (DEX), an α2-adrenoceptor (α2-AR) agonist, has anti-inflammatory effects. We investigated the protective effects of DEX on sepsis-induced AKI and the expression of BMP-7 and histone deacetylases (HDACs). In vitro , the effects of DEX or trichostatin A (TSA, an HDAC inhibitor) on TNF-α, monocyte chemotactic protein (MCP-1), BMP-7, and HDAC mRNA expression in LPS-stimulated rat renal tubular epithelial NRK52E cells, was determined using real-time PCR. In vivo, mice were intraperitoneally injected with DEX (25 μg/kg) or saline immediately and 12 h after cecal ligation and puncture (CLP) surgery. Twenty-four hours after CLP, we examined kidney injury and renal TNF-α, MCP-1, BMP-7, and HDAC expression. Survival was monitored for 120 h. LPS increased HDAC2, HDAC5, TNF-α, and MCP-1 expression, but decreased BMP-7 expression in NRK52E cells. DEX treatment decreased the HDAC2, HDAC5, TNF-α, and MCP-1 expression, but increased BMP-7 and acetyl histone H3 expression, whose effects were blocked by yohimbine, an α2-AR antagonist. With DEX treatment, the LPS-induced TNF-α expression and cell death were attenuated in scRNAi-NRK52E but not BMP-7 RNAi-NRK52E cells. In CLP mice, DEX treatment increased survival and attenuated AKI. The expression of HDAC2, HDAC5, TNF-α, and MCP-1 mRNA in the kidneys of CLP mice was increased, but BMP-7 was decreased. However, DEX treatment reduced those changes. DEX reduces sepsis-induced AKI by decreasing TNF-α and MCP-1 and increasing BMP-7, which is associated with decreasing HDAC2 and HDAC5, as well as increasing acetyl histone H3.

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Investigating the blood–spinal cord barrier in preclinical models: a systematic review of in vivo imaging techniques

Spinal Cord ◽

10.1038/s41393-021-00623-7 ◽

2021 ◽

Author(s):

Joshua Bakhsheshian ◽

Ben A. Strickland ◽

William J. Mack ◽

Berislav V. Zlokovic

Keyword(s):

Systematic Review ◽

Spinal Cord ◽

In Vivo Imaging ◽

Imaging Techniques ◽

Preclinical Models ◽

Blood Spinal Cord Barrier

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In Vivo Imaging of Peripheral Benzodiazepine Receptors in Mouse Lungs: A Biomarker of Inflammation

Molecular Imaging ◽

10.2310/7290.2005.05133 ◽

2005 ◽

Vol 4 (4) ◽

pp. 7290.2005.05133 ◽

Cited By ~ 19

Author(s):

Matthew J. Hardwick ◽

Ming-Kai Chen ◽

Kwamena Baidoo ◽

Martin G. Pomper ◽

Tomás R. Guilarte

Keyword(s):

In Vivo Imaging ◽

Ex Vivo ◽

Inflammatory Diseases ◽

Imaging Techniques ◽

Benzodiazepine Receptors ◽

Small Animal ◽

Small Animal Pet ◽

Planar Imaging ◽

Peripheral Benzodiazepine Receptors

The ability to visualize the immune response with radioligands targeted to immune cells will enhance our understanding of cellular responses in inflammatory diseases. Peripheral benzodiazepine receptors (PBR) are present in monocytes and neutrophils as well as in lung tissue. We used lipopolysaccharide (LPS) as a model of inflammation to assess whether the PBR could be used as a noninvasive marker of inflammation in the lungs. Planar imaging of mice administrated 10 or 30 mg/kg LPS showed increased [123I]-( R)-PK11195 radioactivity in the thorax 2 days after LPS treatment relative to control. Following imaging, lungs from control and LPS-treated mice were harvested for ex vivo gamma counting and showed significantly increased radioactivity above control levels. The specificity of the PBR response was determined using a blocking dose of nonradioactive PK11195 given 30 min prior to radiotracer injection. Static planar images of the thorax of nonradioactive PK11195 pretreated animals showed a significantly lower level of radiotracer accumulation in control and in LPS-treated animals ( p < .05). These data show that LPS induces specific increases in PBR ligand binding in the lungs. We also used in vivo small-animal PET studies to demonstrate increased [11C]-( R)-PK11195 accumulation in the lungs of LPS-treated mice. This study suggests that measuring PBR expression using in vivo imaging techniques may be a useful biomarker to image lung inflammation.

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Towards in vivo imaging of photoreceptor morphology and function

10.1364/biomed.2008.bmb3 ◽

2008 ◽

Author(s):

B. Hermann ◽

C. Torti ◽

E.J. Fernández ◽

P. Ahnelt ◽

B. Považay ◽

...

Keyword(s):

In Vivo Imaging ◽

And Function

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MiR-22-3p suppresses sepsis-induced acute kidney injury by targeting PTEN

Bioscience Reports ◽

10.1042/bsr20200527 ◽

2020 ◽

Vol 40 (6) ◽

Author(s):

Xudong Wang ◽

Yali Wang ◽

Mingjian Kong ◽

Jianping Yang

Keyword(s):

Acute Kidney Injury ◽

Inflammatory Response ◽

Periodic Acid ◽

Kidney Injury ◽

Luciferase Reporter ◽

Tunel Staining ◽

Tnf Α

Abstract Background: Septic acute kidney injury is considered as a severe and frequent complication that occurs during sepsis. The present study was performed to understand the role of miR-22-3p and its underlying mechanism in sepsis-induced acute kidney injury. Methods: Rats were injected with adenovirus carrying miR-22-3p or miR-NC in the caudal vein before cecal ligation. Meanwhile, HK-2 cells were transfected with the above adenovirus following LPS stimulation. We measured the markers of renal injury (blood urea nitrogen (BUN), serum creatinine (SCR)). Histological changes in kidney tissues were examined by hematoxylin and eosin (H&E), Masson staining, periodic acid Schiff staining and TUNEL staining. The levels of IL-1β, IL-6, TNF-α and NO were determined by ELISA assay. Using TargetScan prediction and luciferase reporter assay, we predicted and validated the association between PTEN and miR-22-3p. Results: Our data showed that miR-22-3p was significantly down-regulated in a rat model of sepsis-induced acute kidney injury, in vivo and LPS-induced sepsis model in HK-2 cells, in vitro. Overexpression of miR-22-3p remarkably suppressed the inflammatory response and apoptosis via down-regulating HMGB1, p-p65, TLR4 and pro-inflammatory factors (IL-1β, IL-6, TNF-α and NO), both in vivo and in vitro. Moreover, PTEN was identified as a target of miR-22-3p. Furthermore, PTEN knockdown augmented, while overexpression reversed the suppressive role of miR-22-3p in LPS-induced inflammatory response. Conclusions: Our results showed that miR-22-3p induced protective role in sepsis-induced acute kidney injury may rely on the repression of PTEN.

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TRPV4-mediated Ca2+ influx is essential to glomerular endothelial inflammation in sepsis associated acute kidney injury

10.21203/rs.3.rs-1031344/v1 ◽

2021 ◽

Author(s):

Xia Wang ◽

Yinhua Wang ◽

Guo Zhou ◽

Yi Li ◽

Huanhuan Huo ◽

...

Keyword(s):

Acute Kidney Injury ◽

Endothelial Cells ◽

Cell Injury ◽

Cecal Ligation ◽

Kidney Injury ◽

Blood Perfusion ◽

High Morbidity ◽

Endothelial Inflammation ◽

Glomerular Endothelial Cells

Abstract Background Sepsis-associated acute kidney injury (S-AKI) is a frequent complication of critical patients and is associated with high morbidity and mortality. The glomerular endothelial cell injury is the main characteristics during S-AKI. Ca2+ influx is a key step in the establishment of endothelial injury. Transient receptor vanilloid subtype 4 (TRPV4) ion channels are permeable to Ca2+ and are widely expressed in endothelial cells. However, the role of TRPV4 on glomerular endothelial inflammation in S-AKI has remained elusive. Methods Mouse glomerular endothelial cells (MRGEC) were used to test the molecular mechanism of TRPV4 on LPS-induced glomerular endothelial inflammation. The cecal-ligation-and-puncture (CLP) model was established by ligation of cecum with 4-0 suture and punctured with a 21-gauge needle. Then 0.2mL faeces was extruded from the puncture site to trigger peritoneal inflammation. Results In the present study, we found that blocking TRPV4 diminishes LPS-induced cytosolic Ca2+-elevations, which are essential for glomerular endothelial inflammation and barrier function. Furthermore, TRPV4 regulated LPS-induced phosphorylation and translocation of NF-κB and IRF-3 in mouse glomerular endothelial cells (MRGEC). Clamping intracellular Ca2+ mimics the LPS-induce response seen in the absence of TRPV4. In vivo, pharmacological blockade or knock down of TRPV4 reduced the inflammatory response of glomerular endothelial cells, inhibited translocation of NF-κB and IRF-3, increased survival rate and improved renal function in CLP-induced sepsis but without altering renal cortical blood perfusion. Conclusions Taken together, these results suggested that inhibition of TRPV4 ameliorates glomerular endothelial inflammation, kidney dysfunction, and increased mortality via mediating Ca2+ overload and NF-κB/IRF-3 activation. These discoveries may provide novel pharmacological strategies for the treatment of glomerular endothelial dysfunction and kidney injury during endotoxemia, sepsis, and other inflammatory diseases.

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